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1

Platinum Nanoclusters Out-Perform Single Crystals  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Platinum Nanoclusters Out-Perform Single Crystals Print Platinum Nanoclusters Out-Perform Single Crystals Print When it comes to metal catalysts, platinum is the standard. However, at about $2,000 an ounce, the high cost of the raw material presents major challenges for the future wide-scale use of platinum in fuel cells. Berkeley Lab research suggests that one possible way to meet these challenges is to think small. Researchers from Berkeley Lab's Materials Sciences Division have found that under high pressure-comparable to the pressures at which many industrial technologies operate-platinum surfaces can change their structure dramatically in response to the presence of high-coverage reactants. High-pressure scanning tunneling microscopes (STM) and ambient-pressure x-ray photoelectron spectroscopy (AP-XPS) at ALS Beamlines 9.3.2 and 11.0.2 allowed researchers to study catalysts' structure and composition under realistic conditions.

2

Platinum Nanoclusters Out-Perform Single Crystals  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Platinum Nanoclusters Out-Perform Single Crystals Print Platinum Nanoclusters Out-Perform Single Crystals Print When it comes to metal catalysts, platinum is the standard. However, at about $2,000 an ounce, the high cost of the raw material presents major challenges for the future wide-scale use of platinum in fuel cells. Berkeley Lab research suggests that one possible way to meet these challenges is to think small. Researchers from Berkeley Lab's Materials Sciences Division have found that under high pressure-comparable to the pressures at which many industrial technologies operate-platinum surfaces can change their structure dramatically in response to the presence of high-coverage reactants. High-pressure scanning tunneling microscopes (STM) and ambient-pressure x-ray photoelectron spectroscopy (AP-XPS) at ALS Beamlines 9.3.2 and 11.0.2 allowed researchers to study catalysts' structure and composition under realistic conditions.

3

Platinum Nanoclusters Out-Perform Single Crystals  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Platinum Nanoclusters Out-Perform Single Crystals Print Platinum Nanoclusters Out-Perform Single Crystals Print When it comes to metal catalysts, platinum is the standard. However, at about $2,000 an ounce, the high cost of the raw material presents major challenges for the future wide-scale use of platinum in fuel cells. Berkeley Lab research suggests that one possible way to meet these challenges is to think small. Researchers from Berkeley Lab's Materials Sciences Division have found that under high pressure-comparable to the pressures at which many industrial technologies operate-platinum surfaces can change their structure dramatically in response to the presence of high-coverage reactants. High-pressure scanning tunneling microscopes (STM) and ambient-pressure x-ray photoelectron spectroscopy (AP-XPS) at ALS Beamlines 9.3.2 and 11.0.2 allowed researchers to study catalysts' structure and composition under realistic conditions.

4

Platinum Nanoclusters Out-Perform Single Crystals  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Platinum Nanoclusters Out-Perform Single Crystals Print Platinum Nanoclusters Out-Perform Single Crystals Print When it comes to metal catalysts, platinum is the standard. However, at about $2,000 an ounce, the high cost of the raw material presents major challenges for the future wide-scale use of platinum in fuel cells. Berkeley Lab research suggests that one possible way to meet these challenges is to think small. Researchers from Berkeley Lab's Materials Sciences Division have found that under high pressure-comparable to the pressures at which many industrial technologies operate-platinum surfaces can change their structure dramatically in response to the presence of high-coverage reactants. High-pressure scanning tunneling microscopes (STM) and ambient-pressure x-ray photoelectron spectroscopy (AP-XPS) at ALS Beamlines 9.3.2 and 11.0.2 allowed researchers to study catalysts' structure and composition under realistic conditions.

5

Platinum Nanoclusters Out-Perform Single Crystals  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Platinum Nanoclusters Out-Perform Single Crystals Print Platinum Nanoclusters Out-Perform Single Crystals Print When it comes to metal catalysts, platinum is the standard. However, at about $2,000 an ounce, the high cost of the raw material presents major challenges for the future wide-scale use of platinum in fuel cells. Berkeley Lab research suggests that one possible way to meet these challenges is to think small. Researchers from Berkeley Lab's Materials Sciences Division have found that under high pressure-comparable to the pressures at which many industrial technologies operate-platinum surfaces can change their structure dramatically in response to the presence of high-coverage reactants. High-pressure scanning tunneling microscopes (STM) and ambient-pressure x-ray photoelectron spectroscopy (AP-XPS) at ALS Beamlines 9.3.2 and 11.0.2 allowed researchers to study catalysts' structure and composition under realistic conditions.

6

Platinum Nanoclusters Out-Perform Single Crystals  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Platinum Nanoclusters Out-Perform Single Crystals Print Platinum Nanoclusters Out-Perform Single Crystals Print When it comes to metal catalysts, platinum is the standard. However, at about $2,000 an ounce, the high cost of the raw material presents major challenges for the future wide-scale use of platinum in fuel cells. Berkeley Lab research suggests that one possible way to meet these challenges is to think small. Researchers from Berkeley Lab's Materials Sciences Division have found that under high pressure-comparable to the pressures at which many industrial technologies operate-platinum surfaces can change their structure dramatically in response to the presence of high-coverage reactants. High-pressure scanning tunneling microscopes (STM) and ambient-pressure x-ray photoelectron spectroscopy (AP-XPS) at ALS Beamlines 9.3.2 and 11.0.2 allowed researchers to study catalysts' structure and composition under realistic conditions.

7

Platinum Nanoclusters Out-Perform Single Crystals  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Platinum Nanoclusters Out-Perform Single Platinum Nanoclusters Out-Perform Single Crystals Platinum Nanoclusters Out-Perform Single Crystals Print Wednesday, 27 October 2010 00:00 When it comes to metal catalysts, platinum is the standard. However, at about $2,000 an ounce, the high cost of the raw material presents major challenges for the future wide-scale use of platinum in fuel cells. Berkeley Lab research suggests that one possible way to meet these challenges is to think small. Researchers from Berkeley Lab's Materials Sciences Division have found that under high pressure-comparable to the pressures at which many industrial technologies operate-platinum surfaces can change their structure dramatically in response to the presence of high-coverage reactants. High-pressure scanning tunneling microscopes (STM) and ambient-pressure x-ray photoelectron spectroscopy (AP-XPS) at ALS Beamlines 9.3.2 and 11.0.2 allowed researchers to study catalysts' structure and composition under realistic conditions.

8

SINGLE CRYSTAL NEUTRON DIFFRACTION.  

SciTech Connect (OSTI)

Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

KOETZLE,T.F.

2001-03-13T23:59:59.000Z

9

PHOTOCATALYTIC AND PHOTOELECTROCHEMICAL HYDROGEN PRODUCTION ON STRONTIUM TITANATE SINGLE CRYSTALS  

E-Print Network [OSTI]

HYDROGEN PRODUCTION ON STRONTIUM TITANATE SINGLE CRYSTALS F.HYDROGEN PRODUCTION ON STRONTIUM TITANATE SINGLE CRYSTALS

Wagner, F.T.

2012-01-01T23:59:59.000Z

10

Photon tunnelling microscopy of polyethylene single crystals  

E-Print Network [OSTI]

Photon tunnelling microscopy of polyethylene single crystals Mohan Srinivasarao* and Richard S:photon tunnellingmicroscopy;single crystals; polyethylene) INTRODUCTION The study of morphology of polymers is an area

Srinivasarao, Mohan

11

Nanoscale Calorimetry of Isolated Polyethylene Single Crystals  

E-Print Network [OSTI]

Nanoscale Calorimetry of Isolated Polyethylene Single Crystals A. T. KWAN, M. YU. EFREMOV, E. A-film differential scanning calorimetry to investigate the melt- ing of isolated polyethylene single crystals of lamellar single crystals of polyethylene (PE). We obtain thickness, diffraction, and calorimetry data

Allen, Leslie H.

12

Ames Lab 101: Single Crystal Growth  

SciTech Connect (OSTI)

Ames Laboratory scientist Deborah Schlagel talks about the Lab's research in growing single crystals of various metals and alloys. The single crystal samples are vital to researchers' understanding of the characteristics of a materials and what gives these materials their particular properties.

Schlagel, Deborah

2013-09-27T23:59:59.000Z

13

Development of single crystal filaments. Final report  

SciTech Connect (OSTI)

The program just completed addresses a route to a more efficient longer-lasting electric light bulb filament. All current filaments for light bulbs are metallic in nature. They are subject to embrittlement with age (large grain growth) and relatively high vapor pressures which limits their operating temperature. There is evidence which suggests advantages to using high temperature refractory single crystal fibers as a filament for a light bulb. These refractory materials may include materials such as hafnium or tantalum carbide which have melting points about 500{degrees}C higher than tungsten. Another advantage is that single crystal fibers have a very high degree of crystalline perfection with very few voids and dislocations. Without these imperfections, the atomic mobility at high temperatures is highly restricted. Thus single crystal fibers are very stable at high temperature and will last longer. The efficiencies result from running these single crystal ceramic fiber filaments at higher temperatures and the higher emissivity of the carbide filaments compared to tungsten. The amount of visible light is proportional to the 4the power of the temperature thus a 500{degrees}C higher operating give about a 3-fold increase in radiation in the visible range. The program accomplishments can be summarized as follows: (1) Single crystal fibers of JfC sufficient crystal quality for light bulb filament applications were made. (2) The HfC fiber furnace growth chamber, power control and data collection system was developed for the laboratory scale plant. (3) method for mounting and apparatuses for testing the single crystal fiber filaments were developed and built.

Milewski, J.V.; Shoultz, R.A.; Bourque-McConnell, M.M.

1995-04-01T23:59:59.000Z

14

Neutron detection with single crystal organic scintillators  

SciTech Connect (OSTI)

Detection of high-energy neutrons in the presence of gamma radiation background utilizes pulse-shape discrimination (PSD) phenomena in organics studied previously only with limited number of materials, mostly liquid scintillators and single crystal stilbene. The current paper presents the results obtained with broader varieties of luminescent organic single crystals. The studies involve experimental tools of crystal growth and material characterization in combination with the advanced computer modeling, with the final goal of better understanding the relevance between the nature of the organic materials and their PSD properties. Special consideration is given to the factors that may diminish or even completely obscure the PSD properties in scintillating crystals. Among such factors are molecular and crystallographic structures that determine exchange coupling and exciton mobility in organic materials and the impurity effect discussed on the examples of trans-stilbene, bibenzyl, 9,10-diphenylanthracene and diphenylacetylene.

Zaitseva, N; Newby, J; Hamel, S; Carman, L; Faust, M; Lordi, V; Cherepy, N; Stoeffl, W; Payne, S

2009-07-15T23:59:59.000Z

15

Transverse acoustic actuation of Ni-Mn-Ga single crystals  

E-Print Network [OSTI]

Two methods for the transverse acoustic actuation of {110}-cut Ni-Mn-Ga single crystals are discussed. In this actuation mode, crystals are used that have the {110}- type twinning planes parallel to the base of the crystal. ...

Simon, Jesse Matthew

2007-01-01T23:59:59.000Z

16

Copper diffusion in single-crystal ?-Zr  

Science Journals Connector (OSTI)

Tracer diffusion of Cu64 in ?-Zr single crystals has been measured in the temperature range (615-860)°C. The temperature dependences of the Cu64 diffusion coefficients in directions parallel to and perpendicular to the c axis are given by D?=0.40e-1.54 eVkT and D?=0.25e-1.60 eVkT cm2/sec, respectively. The results are discussed in terms of an interstitial diffusion mechanism.

G. M. Hood and R. J. Schultz

1975-05-15T23:59:59.000Z

17

Solar cell structure incorporating a novel single crystal silicon material  

DOE Patents [OSTI]

A novel hydrogen rich single crystal silicon material having a band gap energy greater than 1.1 eV can be fabricated by forming an amorphous region of graded crystallinity in a body of single crystalline silicon and thereafter contacting the region with atomic hydrogen followed by pulsed laser annealing at a sufficient power and for a sufficient duration to recrystallize the region into single crystal silicon without out-gassing the hydrogen. The new material can be used to fabricate semiconductor devices such as single crystal silicon solar cells with surface window regions having a greater band gap energy than that of single crystal silicon without hydrogen.

Pankove, Jacques I. (Princeton, NJ); Wu, Chung P. (Trenton, NJ)

1983-01-01T23:59:59.000Z

18

Magnetoplasticity and diffusion in silicon single crystals  

SciTech Connect (OSTI)

The effect of static magnetic fields on the dynamics of surface dislocation segments, as well as the diffusion mobility of a dopant in silicon single crystals, has been analyzed. It has been experimentally found that the preliminary treatment of p-type silicon plates (the dopant is boron with a concentration of 10{sup 16} cm{sup -3}) in the static magnetic field (B = 1 T, a treatment time of 30 min) leads to an increase in the mobility of surface dislocation segments. The characteristic times of observed changes (about 80 h) and the threshold dopant concentration (10{sub 15} cm{sup -3}) below which the magneto-optical effect in silicon is not fixed have been determined. It has been found that diffusion processes in dislocation-free silicon are magnetically sensitive: the phosphorus diffusion depth in p-type silicon that is preliminarily aged in the static magnetic field increases (by approximately 20%) compared to the reference samples.

Skvortsov, A. A., E-mail: SkvortsovAA2009@yandex.ru; Karizin, A. V. [Moscow State Technical University 'MAMI' (Russian Federation)

2012-01-15T23:59:59.000Z

19

Nuclear magnetic resonance in a thallium single crystal.  

E-Print Network [OSTI]

??Nuclear magnetic resonance studies in single crystals of thallium have been performed for the first time. The resonance frequency, line width and second moment were… (more)

Schratter, Jacob Jack

2012-01-01T23:59:59.000Z

20

Single crystal Processing and magnetic properties of gadolinium nickel  

SciTech Connect (OSTI)

GdNi is a rare earth intermetallic material that exhibits very interesting magnetic properties. Spontaneous magnetostriction occurs in GdNi at T{sub C}, on the order of 8000ppm strain along the c-axis and only until very recently the mechanism causing this giant magnetostriction was not understood. In order to learn more about the electronic and magnetic structure of GdNi, single crystals are required for anisotropic magnetic property measurements. Single crystal processing is quite challenging for GdNi though since the rare-earth transition-metal composition yields a very reactive intermetallic compound. Many crystal growth methods are pursued in this study including crucible free methods, precipitation growths, and specially developed Bridgman crucibles. A plasma-sprayed Gd{sub 2}O{sub 3} W-backed Bridgman crucible was found to be the best means of GdNi single crystal processing. With a source of high-quality single crystals, many magnetization measurements were collected to reveal the magnetic structure of GdNi. Heat capacity and the magnetocaloric effect are also measured on a single crystal sample. The result is a thorough report on high quality single crystal processing and the magnetic properties of GdNi.

Shreve, Andrew John [Ames Laboratory

2012-11-02T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Constitutive modeling of creep of single crystal superalloys  

E-Print Network [OSTI]

In this work, a constitutive theory is developed, within the context of continuum mechanics, to describe the creep deformation of single crystal superalloys. The con- stitutive model that is developed here is based on the fact that as bodies deform...

Prasad, Sharat Chand

2006-10-30T23:59:59.000Z

22

Ge-Au eutectic bonding of Ge {100} single crystals  

Science Journals Connector (OSTI)

We present preliminary results on the eutectic bonding between two {100} Ge single crystal surfaces using thin films of ... Au sample show epitaxial growth of Ge. In sections of the bond, lattice continuity...

W. B. Knowlton; K. M. Itoh; J. W. Beeman; J. H. Emes…

1993-11-01T23:59:59.000Z

23

Anisotropy of Laser-Induced Bulk Damage of Single Crystals  

E-Print Network [OSTI]

The regularities of laser-induced damage of anisotropic materials, such as LiNbO3 and KDP dielectric single crystals, are experimentally studied. It is revealed that the shape of laser-induced damage in the dielectric crystals depends on the elastic symmetry of crystal and the propagation direction of the laser beam. When the beam propagates along the optic axis of crystals, the figures of the laser damage are six-path stars for LiNbO3 and four-path ones for KDP crystals. For the direction parallel to X and Y axes in KDP crystal, the damage has initially cross-like configuration, with further splitting of Z-oriented crack into two cracks in the process of damage evolution, leading to transformation of orthogonal-type damage to a hexagonal-type one.

Krupych, O; Smaga, I; Vlokh, R

2005-01-01T23:59:59.000Z

24

Epitaxial Single Crystal Nanostructures for Batteries & PVs ...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Electrode Channel Flow DEMS Cell Sulfur@Carbon Cathodes for Lithium Sulfur Batteries Better Ham & Cheese: Enhanced Anodes and Cathodes for Fuel Cells Epitaxial Single...

25

SINGLE CRYSTAL NIOBIUM TUBES FOR PARTICLE COLLIDERS ACCELERATOR CAVITIES  

SciTech Connect (OSTI)

The objective of this research project is to produce single crystal niobium (Nb) tubes for use as particle accelerator cavities for the Fermi laboratory’s International Linear Collider project. Single crystal Nb tubes may have superior performance compared to a polycrystalline tubes because the absence of grain boundaries may permit the use of higher accelerating voltages. In addition, Nb tubes that are subjected to the high temperature, high vacuum crystallization process are very pure and well annealed. Any impurity with a significantly higher vapor pressure than Nb should be decreased by the relatively long exposure at high temperature to the high vacuum environment. After application of the single crystal process, the surfaces of the Nb tubes are bright and shiny, and the tube resembles an electro polished Nb tube. For these reasons, there is interest in single crystal Nb tubes and in a process that will produce single crystal tubes. To convert a polycrystalline niobium tube into a single crystal, the tube is heated to within a few hundred ?C of the melting temperature of niobium, which is 2477 ?C. RF heating is used to rapidly heat the tube in a narrow zone and after reaching the operating temperature, the hot zone is slowly passed along the length of the tube. For crystallization tests with Nb tubes, the traverse rate was in the range of 1-10 cm per hour. All the crystallization tests in this study were performed in a water-cooled, stainless steel chamber under a vacuum of 5 x10-6 torr or better. In earliest tests of the single crystal growth process, the Nb tubes had an OD of 1.9 cm and a wall thickness of 0.15 mm. With these relatively small Nb tubes, the single crystal process was always successful in producing single crystal tubes. In these early tests, the operating temperature was normally maintained at 2200 ?C, and the traverse rate was 5 cm per hour. In the next test series, the Nb tube size was increased to 3.8 cm OD and the wall thickness was increased 0.18 mm and eventually to 0.21 mm. Again, with these larger tubes, single crystal tubes were usually produced by the crystallization process. The power supply was generally operated at full output during these tests, and the traverse rate was 5 cm per hour. In a few tests, the traverse rate was increased to 10 cm per hour, and at the faster traverse rate, single crystal growth was not achieved. In these tests with a faster traverse rate, it was thought that the tube was not heated to a high enough temperature to achieve single crystal growth. In the next series of tests, the tube OD was unchanged at 3.8 cm and the wall thickness was increased to 0.30 mm. The increased wall thickness made it difficult to reach an operating temperature above 2,000 ?C, and although the single crystal process caused a large increase in the crystal grains, no single crystal tubes were produced. It was assumed that the operating temperature in these tests was not high enough to achieve single crystal growth. In FY 2012, a larger power supply was purchased and installed. With the new power supply, temperatures above the melting point of Nb were easily obtained regardless of the tube thickness. A series of crystallization tests was initiated to determine if indeed the operating temperature of the previous tests was too low to achieve single crystal growth. For these tests, the Nb tube OD remained at 3.8 cm and the wall thickness was 0.30 mm. The first test had an operating temperature of 2,000 ?C. and the operating temperature was increased by 50 ?C increments for each successive test. The final test was very near the Nb melting temperature, and indeed, the Nb tube eventually melted in the center of the tube. These tests showed that higher temperatures did yield larger grain sizes if the traverse rate was held constant at 5 cm per hour, but no single crystal tubes were produced even at the highest operating temperature. In addition, slowing the traverse rate to as low as 1 cm per hour did not yield a single crystal tube regardless of operating temperature. At this time, it

MURPHY, JAMES E [University of Nevada, Reno] [University of Nevada, Reno

2013-02-28T23:59:59.000Z

26

Shock Driven Twinning in Tantalum Single Crystals  

SciTech Connect (OSTI)

Recovery based observations of high pressure material behavior generated under high explosively driven flyer based loading conditions are reported. Two shock pressures, 25, and 55 GPa and four orientations {l_brace}(100), (110), (111), (123){r_brace} were considered. Recovered material was characterized using electron backscatter diffraction along with a limited amount of transmission electron microscopy to assess the occurrence of twinning under each test condition. Material recovered from 25 GPa had a very small fraction of twinning for the (100), (110), and (111) oriented crystals while a more noticeable fraction of the (123) oriented crystal was twinned. Material recovered from 55 GPa showed little twinning for (100) orientation slightly more for the (111) orientation and a large area fraction for the (123) orientation. The EBSD and TEM observations of the underlying deformation substructure are rationalized by comparing with previous static and dynamic results.

McNaney, J M; HSUING, L M; Barton, N R; Kumar, M

2009-07-20T23:59:59.000Z

27

Method for harvesting rare earth barium copper oxide single crystals  

DOE Patents [OSTI]

A method of preparing high temperature superconductor single crystals is disclosed. The method of preparation involves preparing precursor materials of a particular composition, heating the precursor material to achieve a peritectic mixture of peritectic liquid and crystals of the high temperature superconductor, cooling the peritectic mixture to quench directly the mixture on a porous, wettable inert substrate to wick off the peritectic liquid, leaving single crystals of the high temperature superconductor on the porous substrate. Alternatively, the peritectic mixture can be cooled to a solid mass and reheated on a porous, inert substrate to melt the matrix of peritectic fluid while leaving the crystals melted, allowing the wicking away of the peritectic liquid. 2 figs.

Todt, V.R.; Sengupta, S.; Shi, D.

1996-04-02T23:59:59.000Z

28

Modelling of Heat Transfer in Single Crystal Growth  

E-Print Network [OSTI]

An attempt is made to review the heat transfer and the related problems encountered in the simulation of single crystal growth. The peculiarities of conductive, convective and radiative heat transfer in the different melt, solution, and vapour growth methods are discussed. The importance of the adequate description of the optical crystal properties (semitransparency, specular reflecting surfaces) and their effect on the heat transfer is stresses. Treatment of the unknown phase boundary fluid/crystal as well as problems related to the assessment of the quality of the grown crystals (composition, thermal stresses, point defects, disclocations etc.) and their coupling to the heat transfer/fluid flow problems is considered. Differences between the crystal growth simulation codes intended for the research and for the industrial applications are indicated. The problems of the code verification and validation are discussed; a brief review of the experimental techniques for the study of heat transfer and flow structu...

Zhmakin, Alexander I

2014-01-01T23:59:59.000Z

29

Growth and characterization of lithium yttrium borate single crystals  

SciTech Connect (OSTI)

Single crystals of 0.1% Ce doped Li{sub 6}Y(BO{sub 3}){sub 3} have been grown using the Czochralski technique. The photoluminescence study of these crystals shows a broad emission at ? 420 nm corresponding to Ce{sub 3+} emission from 5d?4f energy levels. The decay profile of this emission shows a fast response of ? 28 ns which is highly desirable for detector applications.

Singh, A. K.; Singh, S. G.; Tyagi, M.; Desai, D. G.; Sen, Shashwati [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai- 400085 (India)

2014-04-24T23:59:59.000Z

30

Electronic conduction through single crystals of polyethylene  

E-Print Network [OSTI]

May, 1966 Major Subjects Physics ELECTRONIC CONDUCTION THROUGH SINGLE CRYSTRLS OF POLYETHYLENE k Thesis By Gerald Maurice Samson Approved as to style and content by: naen of the Committee ad of the D artment ber ber c- The autho. u... talc o Polyot! ylone . -y, i'oo Gerald !':cur"' co Samson Directed by: Zr. Joe S. The predominant conduction mechani m through single cryo' mls op polyethylene is shown to be Schott!cy ( hernal) oui "sion . or tompora- o tu. es - bove 0 C. . "or...

Samson, Gerald Maurice

1966-01-01T23:59:59.000Z

31

Lithium niobate single-crystal and photo-functional device  

DOE Patents [OSTI]

Provided are lithium niobate single-crystal that requires a low voltage of not larger than 10 kV/nm for its ferroelectric polarization inversion and of which the polarization can be periodically inverted with accuracy even at such a low voltage, and a photo-functional device comprising the crystal. The crystal has a molar fraction of Li.sub.2 O/(Nb.sub.2 O.sub.5 +Li.sub.2 O) of falling between 0.49 and 0.52. The photo-functional device can convert a laser ray being incident thereon.

Gopalan, Venkatraman (State College, PA); Mitchell, Terrence E. (Los Alamos, NM); Kitamura, Kenji (Tsukuba, JP); Furukawa, Yasunori (Tsukuba, JP)

2001-01-01T23:59:59.000Z

32

TOPAZ: the Single Crystal Diffractometer at SNS | ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

TOPAZ-Single-Crystal Diffractometer TOPAZ-Single-Crystal Diffractometer TOPAZ instrument scientist Christina Hoffmann and scientific associate Matt Frost at TOPAZ. TOPAZ instrument scientist Christina Hoffmann and scientific associate Matt Frost at TOPAZ. TOPAZ is an elastic scattering instrument that allows for probing of material structures and responses under controlled environmental conditions. It enables neutron measurement of the same single-crystal samples that is possible with x-ray diffraction. Data are collected on samples of 0.1 mm3 or less. Resolution is such that an average unit cell size of [50 × 50 × 50] Å3 for compounds of moderate complexity can be easily accommodated. This includes inorganic large and porous framework and guest-host materials, metal (in-)organic cluster and

33

Elastic constants of single crystal Hastelloy X at elevated temperatures  

SciTech Connect (OSTI)

An acoustic time of flight technique is described in detail for measuring the elastic constants of cubic single crystals that allows for the constants to be determined at elevated temperature. Although the overall technique is not new, various aspects of the present work may prove extremely useful to others interested in finding these values, especially for aerospace materials applications. Elastic constants were determined for the nickel based alloy, Hastelloy X from room temperature to 1,000 C. Accurate elastic constants were needed as part of an effort to predict both polycrystal mechanical properties and the nature of grain induced heterogeneous mechanical response. The increased accuracy of the acoustically determined constants resulted in up to a 15% change in the predicted stresses in individual grains. These results indicate that the use of elastic single crystal constants of pure nickel as an approximation for the constants of gas turbine single crystal alloys, which is often done today, is inaccurate.

Canistraro, H.A. [Univ. of Hartford, CT (United States). Dept. of Mechanical and Audio Engineering Technology; Jordan, E.H.; Shi Shixiang [Univ. of Connecticut, Storrs, CT (United States); Favrow, L.H.; Reed, F.A. [United Technologies Research Center, East Hartford, CT (United States)

1998-07-01T23:59:59.000Z

34

NANO-SCALE CALORIMETRY OF ISOLATED POLYETHYLENE SINGLE CRYSTALS  

E-Print Network [OSTI]

#12;NANO-SCALE CALORIMETRY OF ISOLATED POLYETHYLENE SINGLE CRYSTALS BY ALEX TAN KWAN B.S., Stanford) device, the nanocalorimeter, it was possible to investigate the melting of isolated polyethylene (PE, a simple Ni-foil calorimeter, to measure the heat capacity of a thin polyethylene film to verify

Allen, Leslie H.

35

Low temperature magnetic transitions of single crystal HoBi  

SciTech Connect (OSTI)

We present resistivity, specific heat and magnetization measurements in high quality single crystals of HoBi, with a residual resistivity ratio of 126. We find, from the temperature and field dependence of the magnetization, an antiferromagnetic transition at 5.7 K, which evolves, under magnetic fields, into a series of up to five metamagnetic phases.

Fente, A. [Universidad Autonoma de Madrid; Suderow, H. [Universidad Autonoma de Madrid; Vieira, S. [Universidad Autonoma de Madrid; Nemes, N. M. [Instituto de Ciencia de Materiales de Madrid; Garcia-Hernandez, M. [Instituto de Ciencia de Materiales de Madrid; Budko, Sergei L. [Ames Laboratory; Canfield, Paul C. [Ames Laboratory

2013-09-04T23:59:59.000Z

36

Photo- and Semi-conductance in Molecular Single Crystals  

Science Journals Connector (OSTI)

... (1) Photo-conductance1 in molecular single crystals of the anthracene type is not an effect due primarily ... anthracene type is not an effect due primarily to impurity centres, since the dependence of photo-conductance on wave-length reproduces all inflexions of the ultra-violet absorption curve of the ...

D. J. CARSWELL; J. FERGUSON; L. E. LYONS

1954-04-17T23:59:59.000Z

37

E-Print Network 3.0 - acid single crystals Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of Chemistry single crystal X-ray diffraction. Consequently, the crystal structure... and methanol, followed by slow evaporation at room temperature ... Source: de Gispert, Adri...

38

Single crystal to single crystal transition in (10, 3)-d framework with pyrazine-2-carboxylate ligand: Synthesis, structures and magnetism  

SciTech Connect (OSTI)

Assembling of pyrazine-2-carboxylate (Pzc) acid with nickel chlorine under solvothermal condition with MeOH as solvent gave a porous complex 1 {l_brace}[Ni(Pzc)ClH{sub 2}O]{center_dot}MeOH{r_brace}{sub n} with 1D channels. In 1 the ligands and metal ions are connected by three of each other and a rare (10,3)-d topology net is gained. The MeOH molecules filled in the 1D channels as guests. It is interesting that 1 undergoes a single-crystal-to-single-crystal transformation to another complex 2 when the guest MeOH molecules in the channels are exchanged by water molecules. Magnetic study indicates anti-ferromagnetic couplings exist in the two complexes and the guest exchange in the complex has little influence on the magnetism. - Graphical abstract: A porous complex 1 with rare (10,3)-d net was gained, and 1 underwent a single-crystal-to-single-crystal transformation to another phase 2. Highlights: Black-Right-Pointing-Pointer New (10,3)-d net was obtained with pyrazine-2-carboxylate ligands as a triangular node. Black-Right-Pointing-Pointer The complex 1 has a 1D channel filled with methanol molecules as guests. Black-Right-Pointing-Pointer 1 could undergo SCSC structural transition to 2 after guests exchanged. Black-Right-Pointing-Pointer Antiferromagnetic interactions were found in 1 and 2.

Yang, Qian [School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin 300384 (China) [School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin 300384 (China); Department of Chemistry, Tianjin Key Lab on Metal and Molecule-based Material Chemistry, Nankai University, Tianjin 300071 (China); Zhao, Jiong-Peng, E-mail: horryzhao@yahoo.com [School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin 300384 (China)] [School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin 300384 (China); Liu, Zhong-Yi [College of Chemistry, Tianjin Key Laboratory of Structure and Performance for Functional Molecules, Tianjin Normal University, Tianjin 300387 (China)] [College of Chemistry, Tianjin Key Laboratory of Structure and Performance for Functional Molecules, Tianjin Normal University, Tianjin 300387 (China)

2012-12-15T23:59:59.000Z

39

Ultrafast dynamics of excitons in tetracene single crystals  

SciTech Connect (OSTI)

Ultrafast exciton dynamics in free standing 200 nm thin tetracene single crystals were studied at room temperature by femtosecond transient absorption spectroscopy in the visible spectral range. The complex spectrally overlapping transient absorption traces of single crystals were systematically deconvoluted. From this, the ultrafast dynamics of the ground, excited, and transition states were identified including singlet exciton fission into two triplet excitons. Fission is generated through both, direct fission of higher singlet states S{sub n} on a sub-picosecond timescale, and thermally activated fission of the singlet exciton S{sub 1} on a 40 ps timescale. The high energy Davydov component of the S{sub 1} exciton is proposed to undergo fission on a sub-picoseconds timescale. At high density of triplet excitons their mutual annihilation (triplet-triplet annihilation) occurs on a <10 ps timescale.

Birech, Zephania; Schwoerer, Heinrich, E-mail: heso@sun.ac.za [Laser Research Institute, Stellenbosch University, Stellenbosch 7600 (South Africa)] [Laser Research Institute, Stellenbosch University, Stellenbosch 7600 (South Africa); Schwoerer, Markus [Department of Physics, University of Bayreuth, Bayreuth (Germany)] [Department of Physics, University of Bayreuth, Bayreuth (Germany); Schmeiler, Teresa; Pflaum, Jens [Experimental Physics VI, University of Würzburg and Bavarian Center for Applied Energy Research, Würzburg (Germany)] [Experimental Physics VI, University of Würzburg and Bavarian Center for Applied Energy Research, Würzburg (Germany)

2014-03-21T23:59:59.000Z

40

Diamond turning of Si and Ge single crystals  

SciTech Connect (OSTI)

Single-point diamond turning studies have been completed on Si and Ge crystals. A new process model was developed for diamond turning which is based on a critical depth of cut for plastic flow-to-brittle fracture transitions. This concept, when combined with the actual machining geometry for single-point turning, predicts that {open_quotes}ductile{close_quotes} machining is a combined action of plasticity and fracture. Interrupted cutting experiments also provide a meant to directly measure the critical depth parameter for given machining conditions.

Blake, P.; Scattergood, R.O.

1988-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Method for thermal processing alumina-enriched spinel single crystals  

DOE Patents [OSTI]

A process for age-hardening alumina-rich magnesium aluminum spinel to obtain the desired combination of characteristics of hardness, clarity, flexural strength and toughness comprises selection of the time-temperature pair for isothermal heating followed by quenching. The time-temperature pair is selected from the region wherein the precipitate groups have the characteristics sought. The single crystal spinel is isothermally heated and will, if heated long enough pass from its single phase through two pre-precipitates and two metastable precipitates to a stable secondary phase precipitate within the spinel matrix. Quenching is done slowly at first to avoid thermal shock, then rapidly. 12 figs.

Jantzen, C.M.

1995-05-09T23:59:59.000Z

42

Performance of Large grain and Single Crystal Niobium Cavities  

SciTech Connect (OSTI)

We have fabricated and tested several single and one multi-cell cavity made from large grain niobium of four different ingots. Two cavities at a frequency of ~ 2.2 GHz were made from single crystal sheets. Large grain material was used for four single cell cavities of the HG â and OC shapes, a 7-cell cavity of the HG â shape â all resonating at 1500 MHz â and an ILC_LL single cell cavity at 1300 MHz. We began to explore also different chemical polishing baths such as a 1:1:1 and a 1:1:2 buffered solution and explored the change of cavity performance as a function of material removal. The results from these preliminary investigations are reported in this contribution.

Kneisel, Peter; Ciovati, Gianluigi; Sekutowicz, Jacek

2006-07-01T23:59:59.000Z

43

Acoustic studies of single?crystal high?temperature superconductors  

Science Journals Connector (OSTI)

The acoustic properties of single crystals of the high?temperature superconductor YBa 2 Cu 3 O 7 have been measured at temperatures between 0.1 and 300 K for frequencies near 103 and 109 Hz. In the GHz regime longitudinal modes have been studied for propagation directions parallel and perpendicular to the c axis. At Tc there is a discontinuity in the soundvelocities and their temperature derivatives from which the anisotropic strain dependences of Tc are obtained. In the kHz regime resonant excitation of flexural modes in thin reeds of YBa 2 Cu 3 O 7 crystals has permitted precise measurement of acoustic damping and dispersion. The temperature?dependent damping is characterized by at least five features associated with the relaxation of defects. At temperatures below 1 K the velocity of sound is consistent with the presence of a broad “glasslike” distribution of tunneling modes.

Brage Golding; W. H. Haemmerle; L. F. Schneemeyer

1988-01-01T23:59:59.000Z

44

Epitaxial graphene prepared by chemical vapor deposition on single crystal thin iridium films on sapphire  

E-Print Network [OSTI]

Epitaxial graphene prepared by chemical vapor deposition on single crystal thin iridium films Cedex 9, France (Dated: 15 March 2011) Uniform single layer graphene was grown on single-crystal Ir. These graphene layers have a single crystallographic orientation and a very low density of defects, as shown

Boyer, Edmond

45

Cleavage crack-tip deformation in single-crystal zinc  

Science Journals Connector (OSTI)

Dislocation distribution ahead of a cleavage crack tip in single crystal Zn is observed by using the etch pit technique. The results show that the distribution has the feature predicted by the DFZ models, and both X1, the distance from the crack tip to the first dislocation and N0, the total number of dislocations ahead of the crack tip, agree with Majumdar and Burns's DFZ theory. The problems of dislocation emission from the crack tip and dislocation shielding effects on the crack tip are also discussed based on the experimental results.

Fu Ran; Q Y Long; T Y Zhang; C W Lung

1989-01-01T23:59:59.000Z

46

NETL: Gasification - Single-Crystal Sapphire Optical Fiber Sensor  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Gasifier Optimization and Plant Supporting Systems Gasifier Optimization and Plant Supporting Systems Single-Crystal Sapphire Optical Fiber Sensor Instrumentation Virginia Polytechnic Institute and State University Center for Photonics Technology Project Number: DE-FC26-99FT40685 Project Description Phase I - The Photonics Laboratory at Virginia Tech has successfully developed a novel temperature sensor capable of operating at temperatures up to 1600 °C and in harsh conditions. The sensor uses single-crystal sapphire to make an optically-based measurement and will fulfill the need for the real-time monitoring of high temperatures created in gasification processes. Phase II - Based on a successful Phase I laboratory demonstration of a Broadband Polarimetric Differential Interferometric (BPDI) temperature sensor, Virginia Tech's Phase II development objective is to further the development of the sensor for industrial use in slagging coal gasifiers. This will include ruggedizing the design of the sensor and creation of a suitable protective housing such that it can be placed into existing ports of coal gasifiers. The potential industrial use of the sensor will be determined through full-scale testing and development. The sensor design and fabrication has been completed and is undergoing testing. Overall performance and survivability of the sensor will be determined.

47

Growth and properties of Lithium Salicylate single crystals  

SciTech Connect (OSTI)

An attractive feature of {sup 6}Li containing fluorescence materials that determines their potential application in radiation detection is the capture reaction with slow ({approx}< 100 keV) neutrons: {sup 6}Li + n = {sup 4}He + {sup 3}H + 4.8MeV. The use of {sup 6}Li-salicylate (LiSal, LiC{sub 6}H{sub 5}O{sub 3}) for thermal neutron detection was previously studied in liquid and polycrystalline scintillators. The studies showed that both liquid and polycrystalline LiSal scintillators could be utilized in pulse shape discrimination (PSD) techniques that enable separation of neutrons from the background gamma radiation. However, it was found that the efficiency of neutron detection using LiSal in liquid solutions was severely limited by its low solubility in commonly used organic solvents like, for example, toluene or xylene. Better results were obtained with neutron detectors containing the compound in its crystalline form, such as pressed pellets, or microscopic-scale (7-14 micron) crystals dispersed in various media. The expectation drown from these studies was that further improvement of pulse height, PSD, and efficiency characteristics could be reached with larger and more transparent LiSal crystals, growth of which has not been reported so far. In this paper, we present the first results on growth and characterization of relatively large, a cm-scale size, single crystals of LiSal with good optical quality. The crystals were grown both from aqueous and anhydrous (methanol) media, mainly for neutron detection studies. However, the results on growth and structural characterization may be interesting for other fields where LiSal, together with other alkali metal salicylates, is used for biological, medical, and chemical (as catalyst) applications.

Zaitseva, N; Newby, J; Hull, G; Saw, C; Carman, L; Cherepy, N; Payne, S

2009-02-13T23:59:59.000Z

48

E-Print Network 3.0 - alpha-zr single crystals Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

3 4 5 > >> 1 X-Ray Production Using Stacked Pyroelectric Crystals Andrew Kovanen, Yaron Danon, Don Gillich Summary: approximately double that of a single crystal.1 This research...

49

Bruker Workshop on Single Crystal X-Ray Diffraction  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Diagnosis and Treatment of Problem Structures: Diagnosis and Treatment of Problem Structures: A Bruker Workshop on Single Crystal X-Ray Diffraction May 30, 2008 Chemistry Department University of Tennessee Knoxville, TN This meeting focuses on the scientific resources of four ORNL user facilities funded by the DOE Office of Basic Energy Sciences. Who Should Attend Synopsis Goals Scheduled Agenda Workshop Materials Confirmed Speakers Important Dates Registration - now open Location - Directions and Map Sponsors Organizing and Local Committee Contacts Relevant Literature, References, Websites Local Information Bruker - UT Workshop Who Should Attend? The Workshop is directed to the newcomer as well as the experienced user of a Bruker Apex / Apex-II system and SHELX software. It will concentrate on hard to solve and/or refine problem structures. We envision it to be

50

Shock compression experiments on Lithium Deuteride single crystals.  

SciTech Connect (OSTI)

S hock compression exper iments in the few hundred GPa (multi - Mabr) regime were performed on Lithium Deuteride (LiD) single crystals . This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17 - 32 km/s. Measurements included pressure, density, and temperature between ~200 - 600 GPa along the Principal Hugoniot - the locus of end states achievable through compression by large amplitude shock waves - as well as pressure and density of re - shock states up to ~900 GPa . The experimental measurements are compared with recent density functional theory calculations as well as a new tabular equation of state developed at Los Alamos National Labs.

Knudson, Marcus D.; Desjarlais, Michael P.; Lemke, Raymond W.

2014-10-01T23:59:59.000Z

51

Oxidation of magnesium single crystals and evaporated films  

Science Journals Connector (OSTI)

The oxidation of (001) and (100) faces of pure magnesium single crystals at 2.5 mm Hg oxygen pressure was measured at 400°C and 440°C by means of an all-quartz, high vacuum microbalance. In a first approximation a parabolic oxidation law is observed. The oxidation rate on the basal plane is initially higher than on the prismatic plane. Electron diffraction patterns and photomicrographs indicate that the oxide has a preferred orientation on the basal plane, even for a thickness of about 1000 Å. The oxidation of evaporated magnesium films at room temperature was also investigated. After an induction period a logarithmic oxidation law is observed, where the limiting thickness is dependent on the oxygen pressure.

R.R Addiss Jr.

1963-01-01T23:59:59.000Z

52

Superconductivity in SrNi2P2 single crystals  

SciTech Connect (OSTI)

Heat capacity, magnetic susceptibility, and resistivity of SrNi{sub 2}P{sub 2} single crystals are presented, illustrating the structural transition at 325 K, and bulk superconductivity at 1.4 K. The magnitude of {Tc}, fits to the heat capacity data, the small upper critical field H{sub c2} = 390 Oe, and {kappa} = 2.1 suggests a conventional fully gapped superconductor. With applied pressure we find that superconductivity persists into the so-called 'collapsed tetragonal' phase, although the transition temperature is monotonically suppressed with increasing pressure. This argues that reduced dimensionality can be a mechanism for increasing the transition temperatures of layered NiP, as well as layered FeAs and NiAs, superconductors.

Ronning, Filip [Los Alamos National Laboratory; Bauer, Eric D [Los Alamos National Laboratory; Park, Tuscon [Los Alamos National Laboratory; Thompson, Joe D [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

53

Single crystal metal wedges for surface acoustic wave propagation  

DOE Patents [OSTI]

An ultrasonic testing device has been developed to evaluate flaws and inhomogeneities in the near-surface region of a test material. A metal single crystal wedge is used to generate high frequency Rayleigh surface waves in the test material surface by conversion of a slow velocity, bulk acoustic mode in the wedge into a Rayleigh wave at the metal-wedge test material interface. Particular classes of metals have been found to provide the bulk acoustic modes necessary for production of a surface wave with extremely high frequency and angular collimation. The high frequency allows flaws and inhomogeneities to be examined with greater resolution. The high degree of angular collimation for the outgoing ultrasonic beam permits precision angular location of flaws and inhomogeneities in the test material surface.

Fisher, E.S.

1980-05-09T23:59:59.000Z

54

Inelastic neutron scattering from single crystal Zn under high pressure  

Science Journals Connector (OSTI)

Inelastic neutron-scattering experiments have been performed for single crystals of Zn under pressures up to 8.8 GPa at 300 K. The phonon modes q/qmax=?=0.075 and ?=0.10 were measured in the transverse acoustic branch ?3, where q=0 corresponds with the elastic constant C44. The phonon energy showed a substantial hardening with increasing pressure. The experimental data below 6.8 GPa for ?=0.075 yield a constant Grüneisen mode ?i=-ln?i/lnV of 2.25 in good agreement with a previous calculation [H. Ledbetter, Phys. Status Solidi B 181, 81 (1994)]. Above 6.8 GPa, there is a very rapid increase of ?i which is indicative of the presence of a giant Kohn anomaly. This rapid divergence at high pressure indicates that a phonon softening may occur at pressures higher than 8.8 GPa caused by the collapse of the giant Kohn anomaly via an electronic topological transition (ETT). In an earlier Mössbauer Zn study at 4 K [W. Potzel et al., Phys. Rev. Lett. 74, 1139 (1994)], a drastic drop of the Lamb-Mössbauer factor was observed at 6.6 GPa, which was interpreted as being due to phonon softening, indicating this ETT had occurred. This paper also compares the compressibility data for single crystal Zn and Zn powder using neutron scattering. The results were found to be similar to an earlier x-ray Zn powder experiment [O. Schulte et al., High Pressure Res. 6, 169 (1991)]. © 1996 The American Physical Society.

J. G. Morgan; R. B. Von Dreele; P. Wochner; S. M. Shapiro

1996-07-01T23:59:59.000Z

55

Growth and characterization of isotopically enriched {sup 70}Ge and {sup 74}Ge single crystals  

SciTech Connect (OSTI)

Isotopically enriched {sup 70}Ge and {sup 74}Ge single crystals were successfully gown by a newly developed vertical Bridgman method. The system allows us to reliably grow high purity Ge single crystals of approximately 1 cm{sup 3} volume. To our knowledge, we have grown the first {sup 70}Ge single crystal. The electrically active chemical impurity concentration for both crystals was found to be {approximately}2 {times} cm{sup {minus}3} which is two order of magnitude better that of {sup 74}Ge crystals previously grown by two different groups. Isotopic enrichment of the {sup 70}Ge and the {sup 74}Ge crystals is 96.3% and 96.8%, respectively. The residual chemical impurities present in both crystals were identified as phosphorus, copper, aluminum, and indium. A wide variety of experiments which take advantage of the isotopic purity of our crystals are discussed.

Itoh, K.

1992-10-01T23:59:59.000Z

56

Growth and characterization of isotopically enriched [sup 70]Ge and [sup 74]Ge single crystals  

SciTech Connect (OSTI)

Isotopically enriched [sup 70]Ge and [sup 74]Ge single crystals were successfully gown by a newly developed vertical Bridgman method. The system allows us to reliably grow high purity Ge single crystals of approximately 1 cm[sup 3] volume. To our knowledge, we have grown the first [sup 70]Ge single crystal. The electrically active chemical impurity concentration for both crystals was found to be [approximately]2 [times] cm[sup [minus]3] which is two order of magnitude better that of [sup 74]Ge crystals previously grown by two different groups. Isotopic enrichment of the [sup 70]Ge and the [sup 74]Ge crystals is 96.3% and 96.8%, respectively. The residual chemical impurities present in both crystals were identified as phosphorus, copper, aluminum, and indium. A wide variety of experiments which take advantage of the isotopic purity of our crystals are discussed.

Itoh, K.

1992-10-01T23:59:59.000Z

57

Ductility and chemical reactions at the interface between nickel and magnesium oxide single crystals.  

E-Print Network [OSTI]

??An investigation was conducted on the interaction between nickel metal and single crystals of magnesium oxide. The nickel was cleaned with purified hydrogen gas at… (more)

Hasselman, Didericus Petrus Hermannus

2011-01-01T23:59:59.000Z

58

Polymorphic single crystal {r_reversible} single crystal transition in K{sub 0.975}Rb{sub 0.025}NO{sub 3}  

SciTech Connect (OSTI)

Polymorphic transformations in K{sub 0.975}Rb{sub 0.025}NO{sub 3} single crystals have been investigated by optical microscopy and X-ray diffraction. The equilibrium temperature between modifications II and III has been determined. It is established that the crystal growth at II {r_reversible} III polymorphic transitions is accompanied by the formation and growth of daughter-modification nuclei in the matrix crystal.

Asadov, Yu. G., E-mail: yusifasadov@rambler.ru; Nasirov, E. V. [Azerbaijan National Academy of Sciences, Institute of Physics (Azerbaijan)

2010-09-15T23:59:59.000Z

59

SINGLE-CRYSTAL SAPPHIRE OPTICAL FIBER SENSOR INSTRUMENTATION  

SciTech Connect (OSTI)

Accurate measurement of temperature is essential for the safe and efficient operation and control of a wide range of industrial processes. Appropriate techniques and instrumentation are needed depending on the temperature measurement requirements in different industrial processes and working environments. Harsh environments are common in many industrial applications. These harsh environments may involve extreme physical conditions, such as high-temperature, high-pressure, corrosive agents, toxicity, strong electromagnetic interference, and high-energy radiation exposure. Due to these severe environmental conditions, conventional temperature sensors are often difficult to apply. This situation has opened a new but challenging opportunity for the sensor society to provide robust, high-performance, and cost-effective temperature sensors capable of operating in those harsh environments. The focus of this research program has been to develop a temperature measurement system for temperature measurements in the primary and secondary stages of slagging gasifiers. For this application the temperature measurement system must be able to withstand the extremely harsh environment posed by the high temperatures and corrosive agents present in these systems. Real-time, accurate and reliable monitoring of temperature for the coal gasification process is important to realize the full economic potential of these gasification systems. Long life and stability of operation in the high temperature environment is essential for the temperature measurement system to ensure the continuous running of the coal gasification system over the long term. In this high temperature and chemically corrosive environment, rather limited high temperature measurement techniques such as high temperature thermocouples and optical/acoustic pyrometers are available, each with their own limitations. In this research program, five different temperature sensing schemes based on the single crystal sapphire material were thoroughly investigated to determine an optimal approach for on-line, real-time, reliable, long-term monitoring of temperatures inside the coal gasification environment. Among these were a sapphire fiber extrinsic Fabry-Perot interferometric (EFPI) sensor; an intensity-measurement based polarimetric sapphire sensor and a broadband polarimetric differential interferometric (BPDI) sapphire sensor. Based on the current evaluation and analysis of the experimental results, the broadband polarimetric differential interferometric (BPDI) sensor system was chosen for further prototype instrumentation development because of it's superior performance compared to the other systems. This approach is based on the self-calibrating measurement of the optical path length differences in a single-crystal sapphire disk, which is a function of both the temperature dependent birefringence and the temperature dependent dimensional changes.

A. Wang; G. Pickrell; R. May

2002-09-10T23:59:59.000Z

60

SINGLE-CRYSTAL SAPPHIRE OPTICAL FIBER SENSOR INSTRUMENTATION  

SciTech Connect (OSTI)

Accurate measurement of temperature is essential for the safe and efficient operation and control of a wide range of industrial processes. Appropriate techniques and instrumentation are needed depending on the temperature measurement requirements in different industrial processes and working environments. Harsh environments are common in many industrial applications. These harsh environments may involve extreme physical conditions, such as high-temperature, high-pressure, corrosive agents, toxicity, strong electromagnetic interference, and high-energy radiation exposure. Due to these severe environmental conditions, conventional temperature sensors are often difficult to apply. This situation has opened a new but challenging opportunity for the sensor society to provide robust, high-performance, and cost-effective temperature sensors capable of operating in those harsh environments. The focus of this research program has been to develop a temperature measurement system for temperature measurements in the primary and secondary stages of slagging gasifiers. For this application the temperature measurement system must be able to withstand the extremely harsh environment posed by the high temperatures and corrosive agents present in these systems. Real-time, accurate and reliable monitoring of temperature for the coal gasification process is important to realize the full economic potential of these gasification systems. Long life and stability of operation in the high temperature environment is essential for the temperature measurement system to ensure the continuous running of the coal gasification system over the long term. In this high temperature and chemically corrosive environment, rather limited high temperature measurement techniques such as high temperature thermocouples and optical/acoustic pyrometers are available, each with their own limitations. In this research program, five different temperature sensing schemes based on the single crystal sapphire material were thoroughly investigated to determine an optimal approach for on-line, real-time, reliable, long-term monitoring of temperatures inside the coal gasification environment. Among these were a sapphire fiber extrinsic Fabry-Perot interferometric (EFPI) sensor; an intensity-measurement based polarimetric sapphire sensor and a broadband polarimetric differential interferometric (BPDI) sapphire sensor. Based on the current evaluation and analysis of the experimental results, the BPDI sensor system was chosen for further prototype instrumentation development because of it's superior performance compared to the other systems. This approach is based on the self-calibrating measurement of the optical path length differences in a single-crystal sapphire disk, which is a function of both the temperature dependent birefringence and the temperature dependent dimensional changes.

A. Wang; G. Pickrell; R. May

2002-10-18T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Microhardness of Czochralski-grown single crystals of VB{sub 2}  

SciTech Connect (OSTI)

Single crystals of congruent melting hexagonal VB{sub 2} were grown used a triarc furnace applying the Czochralski technique. Orientation dependent microhardness measurements on a single crystal reveal quasi similar hardness in the crystallographic directions <00.1> and <10.0>, whereas the <10.1> shows slightly lower values.

Bulfon, C.; Sassik, H. [Institut fuer Experimentalphysik, Wien (Austria)] [Institut fuer Experimentalphysik, Wien (Austria); Leithe-Jasper, A.; Rogl, P. [Universitaet Wien (Austria)] [Universitaet Wien (Austria)

1997-10-01T23:59:59.000Z

62

Growth and electrochromic properties of single-crystal V2O5 nanorod arrays  

E-Print Network [OSTI]

Growth and electrochromic properties of single-crystal V2O5 nanorod arrays Katsunori Takahashi reports a study on the template-based growth and electrochromic properties of single-crystal vanadium demonstrated significantly enhanced electrochromic properties; both the larger change of transmittance

Cao, Guozhong

63

Oxygen diffusion in titanite: Lattice diffusion and fast-path diffusion in single crystals  

E-Print Network [OSTI]

Oxygen diffusion in titanite: Lattice diffusion and fast-path diffusion in single crystals X June 2006 Editor: P. Deines Abstract Oxygen diffusion in natural and synthetic single-crystal titanite was characterized under both dry and water-present conditions. For the dry experiments, pre-polished titanite

Watson, E. Bruce

64

Single Crystal Diamond Beam Position Monitors with Radiofrequency Electronic Readout  

SciTech Connect (OSTI)

Over the energy range 5{approx}30 keV a suitably contacted, thin ({approx}100 {mu}m) diamond plate can be operated in situ as a continuous monitor of X-ray beam intensity and position as the diamond absorbs only a small percentage of the incident beam. Single crystal diamond is a completely homogeneous material showing fast (ns), spatially uniform signal response and negligible (

Solar, B.; Graafsma, H.; Potdevin, G.; Trunk, U. [Hasylab, Deutsches Elektronen Synchroton, Hamburg (Germany); Morse, J.; Salome, M. [Instrumentation Services and Development Division, European Synchroton Radiation Facility, Grenoble (France)

2010-06-23T23:59:59.000Z

65

Comparative studies of mercury cadmium telluride single crystal and epitaxial  

Science Journals Connector (OSTI)

We have carried out a systematic study of mercurycadmium telluride (MCT) bulk single crystal and epilayers using electrolyte electroreflectance (EER). Our results and others discussed here suggest that much of the unusual properties of this material are due to structural microdomains. Under mechanical stresses or chemical attack the walls of these domains tend to move via the generation and propagation of defects associated with cationic diffusion. A typical consequence is the creation of n?type zones within a p?type matrix. We have calibrated our etch rate so as to be able to apply EER to the study of the profiles of epilayers with a depth resolution of 200 Å. The technique was applied to more than 100 samples of all origins. The results are summarized here in qualitative terms such as typical profile features as well as in quantitative terms such as compositional variations and defect densities. EER results are integrated within the conceptual framework introduced above and compared to SIMS and microprobe results.

Paul M. Raccah; U. Lee

1983-01-01T23:59:59.000Z

66

DEVELOPMENT OF PROTECTIVE COATINGS FOR SINGLE CRYSTAL TURBINE BLADES  

SciTech Connect (OSTI)

Turbine blades in coal derived syngas systems are subject to oxidation and corrosion due to high steam temperature and pressure. Thermal barrier coatings (TBCs) are developed to address these problems. The emphasis is on prime-reliant design and a better coating architecture, having high temperature and corrosion resistance properties for turbine blades. In Phase I, UES Inc. proposed to develop, characterize and optimize a prime reliant TBC system, having smooth and defect-free NiCoCrAlY bond layer and a defect free oxide sublayer, using a filtered arc technology. Phase I work demonstrated the deposition of highly dense, smooth and defect free NiCoCrAlY bond coat on a single crystal CMSX-4 substrate and the deposition of alpha-alumina and yttrium aluminum garnet (YAG) sublayer on top of the bond coat. Isothermal and cyclic oxidation test and pre- and post-characterization of these layers, in Phase I work, (with and without top TBC layer of commercial EB PVD YSZ) revealed significant performance enhancement.

Amarendra K. Rai

2006-12-04T23:59:59.000Z

67

Radiation tolerance of piezoelectric bulk single-crystal aluminum nitride  

SciTech Connect (OSTI)

For practical use in harsh radiation environments, we pose selection criteria for piezoelectric materials for nondestructive evaluation (NDE) and material characterization. Using these criteria, piezoelectric aluminum nitride is shown to be an excellent candidate. The results of tests on an aluminumnitride-based transducer operating in a nuclear reactor are also presented. We demonstrate the tolerance of single-crystal piezoelectric aluminum nitride after fast and thermal neutron fluences of 1.85 × 1018 neutron/cm2 and 5.8 × 1018 neutron/cm2, respectively, and a gamma dose of 26.8 MGy. The radiation hardness of AlN is most evident from the unaltered piezoelectric coefficient d33, which measured 5.5 pC/N after a fast and thermal neutron exposure in a nuclear reactor core for over 120 MWh, in agreement with the published literature value. The results offer potential for improving reactor safety and furthering the understanding of radiation effects on materials by enabling structural health monitoring and NDE in spite of the high levels of radiation and high temperatures, which are known to destroy typical commercial ultrasonic transducers.

David A. Parks; Bernhard R. Tittmann

2014-07-01T23:59:59.000Z

68

Diffusion in single crystals of melilite: I. Oxygen  

SciTech Connect (OSTI)

Diffusion profiles of {sup 18}O tracer in single crystals of gehlenite and akermanite following annealing at 1,000{degree}-1,300{degree}C have been determined by a depth-profiling technique using secondary ion mass spectrometry. From the {sup 18}O depth profiling the lattice diffusion coefficients for oxygen along the crystallographic axes in gehlenite and akermanite, D{sup 1}{sub geh}//c, D{sup 1}{sub ak}//{alpha} and D{sup 1}{sub ak}//c, respectively, are given by three different equations. Present results are two to four orders of magnitude lower than those previously reported for melilite solid solutions. These high diffusion rates in melilite solid solutions and the heterogeneous distribution of O isotopes in the Allende Ca, Al-rich inclusions (CAIs) have been examined considering the contribution of fast diffusion along dislocations and possible changes in diffusion rate with gehlenite-akermanite ratios in melilite. For this purpose, diffusion coefficients of O along dislocations were calculated by analyzing tailing of the O-diffusion profiles. From the effective diffusion rate in melilite solid solution obtained by lattice and dislocation diffusion rates, it is unlikely that the O-isotope differences in the Allende CAI minerals are the result of diffusion processes during a postcrystallization thermal event.

Yurimoto, Hisayoshi (Univ. of Tsukuba, Ibaraki (Japan)); Morioka, Masana (Univ. of Tokyo (Japan)); Nagasawa, Hiroshi (Gakushuin Univ., Tokyo (Japan))

1989-09-01T23:59:59.000Z

69

The crystal structure of {pi}-ErBO{sub 3}: New single-crystal data for an old problem  

SciTech Connect (OSTI)

Single crystals of the orthoborate {pi}-ErBO{sub 3} were synthesized from Er{sub 2}O{sub 3} and B{sub 2}O{sub 3} under high-pressure/high-temperature conditions of 2 GPa and 800 {sup o}C in a Walker-type multianvil apparatus. The crystal structure was determined on the basis of single-crystal X-ray diffraction data, collected at room temperature. The title compound crystallizes in the monoclinic pseudowollastonite-type structure, space group C2/c, with the lattice parameters a=1128.4(2) pm, b=652.6(2) pm, c=954.0(2) pm, and {beta}=112.8(1){sup o} (R{sub 1}=0.0124 and wR{sub 2}=0.0404 for all data). -- graphical abstract: The first satisfying single-crystal structure determination of {pi}-ErBO{sub 3} sheds light on the extensively discussed structure of {pi}-orthoborates. The application of light pressure during the solid state synthesis yielded in high-quality crystals, due to pressure-induced crystallization. Research highlights: {yields} High-quality single crystals of {pi}-ErBO{sub 3} were prepared via high-pressure-induced crystallization. {yields} At least five different space groups for the rare-earth {pi}-orthoborates are reported. {yields} {pi}-ErBO{sub 3} is isotypic to the pseudowollastonite-type CaSiO{sub 3}. {yields} Remaining ambiguities regarding the structure of the rare-earth {pi}-orthoborates are resolved.

Pitscheider, Almut [Institut fuer Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Universitaet Innsbruck, Innrain 52a, A-6020 Innsbruck (Austria); Kaindl, Reinhard [Institut fuer Mineralogie und Petrographie, Leopold-Franzens-Universitaet Innsbruck, Innrain 52, A-6020 Innsbruck (Austria); Oeckler, Oliver [Department Chemie, Ludwig-Maximilians-Universitaet Muenchen, Butenandtstrasse 5-13, D-81377 Muenchen (Germany); Huppertz, Hubert, E-mail: Hubert.Huppertz@uibk.ac.a [Institut fuer Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Universitaet Innsbruck, Innrain 52a, A-6020 Innsbruck (Austria)

2011-01-15T23:59:59.000Z

70

Single shot ultrafast dynamic ellipsometry (UDE) of laser-driven shocks in single crystal explosives  

SciTech Connect (OSTI)

We report on the first experiments to measure states in shocked energetic single crystals with dynamic ellipsometry. We demonstrate that these ellipsometric techniques can produce reasonable Hugoniot values using small amounts of crystalline RDX and PETN. Pressures, particle velocities and shock velocities obtained using shocked ellipsometry are comparable to those found using gas-gun flyer plates and molecular dynamics calculations. The adaptation of the technique from uniform thin films of polymers to thick non-perfect crystalline materials was a significant achievement. Correct sample preparation proved to be a crucial component. Through trial and error, we were able to resolve polishing issues, sample quality problems, birefringence effects and mounting difficulties that were not encountered using thin polymer films.

Whitley, Von H [Los Alamos National Laboratory; Mcgrane, Shawn D [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory; Eakins, Dan E [Los Alamos National Laboratory; Bolme, Cindy A [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

71

E-Print Network 3.0 - acetate single crystals Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: precipitate Total crystals Only crystalb 1 30% MPD Na Acetate pH 4.6 0.02 M CaCl2 5.06 197 540 17 1 2 0.4 M K... a single crystal from 755 samples. Note that had the...

72

Increasing 13C CP-MAS NMR Resolution Using Single Crystals: Applicatio...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the resolution in solid state NMR, we investigated the use of single crystals in CP-MAS. Model compounds used were octaethyl porphyrins (NiOEP, H 2 OEP, ZnOEP). Over 200%...

73

Anisotropic dewetting in ultra-thin single-crystal silicon-on-insulator films  

E-Print Network [OSTI]

The single crystal silicon-on-insulator thin film materials system represents both an ideal model system for the study of anisotropic thin film dewetting as well as a technologically important system for the development ...

Danielson, David T. (David Thomas)

2008-01-01T23:59:59.000Z

74

Collecting and Processing Neutron Fibre Diffraction Data from a Single-Crystal Diffractometer  

Science Journals Connector (OSTI)

An optimum strategy for collecting fibre diffraction data from a neutron single-crystal diffractometer is proposed. Methods for processing data collected using this strategy are described and illustrated by studies on cellulose.

Langan, P.

1996-08-01T23:59:59.000Z

75

Observation of Inhomogeneous Spatial Conductivity on YBCO Single Crystal by LT-UHV-STM  

Science Journals Connector (OSTI)

We demonstrated that the current mode STM measurement can be used to reveal the inhomogeneous spatial conductivity of a flat surface. Utilizing this mode on an atomically flat YBCO single crystal with a specif...

R. Itti; Wu Ting; H. Sakai; Y. Yamada; Y. Ishimaru…

1995-01-01T23:59:59.000Z

76

Modelling of high-temperature mechanical behaviour of a single crystal superalloy  

Science Journals Connector (OSTI)

...Introduction The development of single crystal...materials for modern gas turbines has been one of...necessary to develop strategies to extrapolate...particular, the development of an appropriate...creep and R is the gas constant. The...

1997-01-01T23:59:59.000Z

77

Photoionization spectra of silver dimers adsorbed on the surface of a ZnS single crystal  

Science Journals Connector (OSTI)

We use the photostimulated luminescence flash method to measure photoionization spectra of Ag2 clusters adsorbed on the surface of a ZnS single crystal. Adsorbed dimers of silver are prepared by treatment of the ...

O. V. Ovchinnikov; D. A. Minakov; M. S. Smirnov…

2007-07-01T23:59:59.000Z

78

Single-Crystal Sapphire Optical Fiber Sensor Instrumentation for Coal Gasifiers  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Single-Crystal Sapphire Optical Fiber Single-Crystal Sapphire Optical Fiber Sensor Instrumentation for Coal Gasifiers Description Accurate temperature measurement inside a coal gasifier is essential for safe, efficient, and cost-effective operation. However, current sensors are prone to inaccurate readings and premature failure due to harsh operating conditions like high temperature (1,200-1,600 °C), high pressure (up to 500 pounds per square inch gauge [psig]),

79

Single crystal growth and characterization of ilmenite, FeTiO?, for electronic applications  

E-Print Network [OSTI]

SINGLE CRYSTAL GROWTH AND CHARACTERIZATION OF ILMENITE, FeTi03, FOR ELECTRONIC APPUCATIONS A Thesis by BRIAN LEONARD GRIES Submitted to the Office of Graduate Studies Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE December 1988 Major Subject: Electrical Engineering SINGLE CRYSTAL GROWTH AND CHARACTERIZATION OF ILMENITE, FeT)Oq, FOR ELECTRONIC APPLICATIONS A Thesis by BRIAN LEONARD GRIES Approved as to style and content by...

Gries, Brian Leonard

2012-06-07T23:59:59.000Z

80

Modeling the elastic and plastic response of single crystals and polycrystalline aggregates  

E-Print Network [OSTI]

MODELING THE ELASTIC AND PLASTIC RESPONSE OF SINGLE CRYSTALS AND POLYCRYSTALLINE AGGREGATES A Thesis by PARAG VILAS PATWARDHAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 2003 Major Subject: Mechanical Engineering MODELING THE ELASTIC AND PLASTIC RESPONSE OF SINGLE CRYSTALS AND POLYCRYSTALLINE AGGREGATES A Thesis by PARAG VILAS...

Patwardhan, Parag Vilas

2005-02-17T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

OPTIMIZATION OF THE PARAMETERS IN THE RHIC SINGLE CRYSTAL HEAVY ION COLLIMATION.  

SciTech Connect (OSTI)

In the framework of the project to design and test a collimation system prototype using bent channeling crystal for cleaning of the RHIC heavy ion beam halo, we have studied the optimal length and bending angle of a silicon (110) single crystal proposed to be a primary element situated upstream of the traditional heavy amorphous collimator. Besides the matters of the channeling and collimation efficiency, we also looked into the impact the crystal may have on the non-channeled particles that go on circulating in the ring, so as to reduce the momentum offset of the particles scattered of the crystal.

BIRYUKOV,V.M.; CHESNOKOV,Y.A.; KOTOV,V.I.; TRBOJEVIC,D.; STEVENS,A.

1999-03-29T23:59:59.000Z

82

Growth and characterization of nonlinear optical ?-glycine single crystal from lithium acetate as solvent  

Science Journals Connector (OSTI)

Single crystals of organic nonlinear optical material, ?-glycine were grown by slow evaporation technique from aqueous solutions of glycine and lithium acetate. The ?-phase was confirmed by single crystal XRD and powder XRD analysis. Presence of various functional groups was identified by FTIR spectrum analysis. Thermal analysis was performed to study the thermal stability of the grown crystals. The dielectric and microhardness studies of the crystals were determined. The optical analysis shows that UV cut-off of ?-glycine is at 240 nm and it has a wide transparency window. The second harmonic generation relative efficiency of the grown crystals was measured by Kurtz and Perry powder technique using Nd:YAG laser and was observed to be 3.4 times that of potassium dihydrogen orthophosphate.

P.V. Dhanaraj; N.P. Rajesh

2009-01-01T23:59:59.000Z

83

Molecular dynamics simulations of the nano-scale room-temperature oxidation of aluminum single crystals  

E-Print Network [OSTI]

Molecular dynamics simulations of the nano-scale room-temperature oxidation of aluminum single Abstract The oxidation of aluminum single crystals is studied using molecular dynamics (MD) simulations with dynamic charge transfer between atoms. The simulations are performed on three aluminum low-index surfaces

Southern California, University of

84

Plasma synthesis of single-crystal silicon nanoparticles for novel electronic device applications  

Science Journals Connector (OSTI)

Single-crystal nanoparticles of silicon, several tens of nanometres in diameter, may be suitable as building blocks for single-nanoparticle electronic devices. Previous studies of nanoparticles produced in low-pressure plasmas have demonstrated the synthesis of nanocrystals 2–10?nm diameter but larger particles were amorphous or polycrystalline. This work reports the use of a constricted, filamentary capacitively coupled low-pressure plasma to produce single-crystal silicon nanoparticles with diameters between 20 and 80?nm. Particles are highly oriented with predominantly cubic shape. The particle size distribution is rather monodisperse. Electron microscopy studies confirm that the nanoparticles are highly oriented diamond-cubic silicon.

Ameya Bapat; Curtis Anderson; Christopher R Perrey; C Barry Carter; Stephen A Campbell; Uwe Kortshagen

2004-01-01T23:59:59.000Z

85

One-dimensional SnF{sub 2} single crystals in the inner channels of single-wall carbon nanotubes: I. Preparation and basic characterization  

SciTech Connect (OSTI)

One-dimensional (1D) SnF{sub 2} single crystals have been obtained by crystallization from melt in the inner channels of single-wall carbon nanotubes (SWCNTs). SWCNTs with an inner diameter of 1.02-1.4 nm, synthesized by electric-arc discharge and chemically purified, were used for incorporation. The synthesized 1D SnF{sub 2} single crystal-SWCNT composites are basically characterized by X-ray diffraction, energy-dispersive analysis, electron microscopy, and chemical analysis. The characteristic motifs of tin cation distribution in the SWCNT inner channel confirm the formation of SnF{sub 2} single crystals.

Zakalyukin, R. M., E-mail: ruslan@ns.crys.ras.ru; Demyanets, L. N.; Kiselev, N. A.; Kumskov, A. S. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Kislov, M. B.; Krestinin, A. V. [Russian Academy of Sciences, Institute of Problems of Chemical Physics (Russian Federation); Hutchison, J. L. [Department of Materials at Oxford University (United Kingdom)

2010-05-15T23:59:59.000Z

86

E-Print Network 3.0 - alpha-in2se3 single crystals Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

3 4 5 > >> 1 X-Ray Production Using Stacked Pyroelectric Crystals Andrew Kovanen, Yaron Danon, Don Gillich Summary: approximately double that of a single crystal.1 This research...

87

Electrical and mechanical studies of high purity aluminum single crystals at 4.2 K under cyclic strain  

E-Print Network [OSTI]

The objective of this research is to investigate the effects of orientation on strain hardening and resistivity degradation in high purity aluminum single crystals resulting from uniaxial cyclic strain at 4.2 K. Aluminum crystals with various...

Zou, Hong

2012-06-07T23:59:59.000Z

88

Low cost, single crystal-like substrates for practical, high efficiency solar cells  

SciTech Connect (OSTI)

It is well established that high efficiency (20%) solar cells can be routinely fabricated using single crystal photovoltaic (PV) materials with low defect densities. Polycrystalline materials with small grain sizes and no crystallographic texture typically result in reduced efficiences. This has been ascribed primarily to the presence of grain boundaries and their effect on recombination processes. Furthermore, lack of crystallographic texture can result in a large variation in dopant concentrations which critically control the electronic properties of the material. Hence in order to reproducibly fabricate high efficiency solar cells a method which results in near single crystal material is desirable. Bulk single crystal growth of PV materials is cumbersome, expensive and difficult to scale up. We present here a possible route to achieve this if epitaxial growth of photovoltaic materials on rolling-assisted-biaxially textured-substrates (RABiTS) can be achieved. The RABiTS process uses well-established, industrially scaleable, thermomechanical processing to produce a biaxially textured or single-crystal-like metal substrate with large grains (50-100 {mu}m). This is followed by epitaxial growth of suitable buffer layers to yield chemically and structurally compatible surfaces for epitaxial growth of device materials. Using the RABiTS process it should be possible to economically fabricate single-crystal-like substrates of desired sizes. Epitaxial growth of photovoltaic devices on such substrates presents a possible route to obtaining low-cost, high performance solar cells.

Goyal, A.; Specht, E.D.; List, F.A. [and others

1997-09-01T23:59:59.000Z

89

Surface structure of cleaved (001) USb2 single crystal surface  

SciTech Connect (OSTI)

We have achieved what we believe to be the first atomic resolution scanning tunneling microscopy (STM) images for a uranium compound USb2 taken at room temperature. The a, b, and c lattice parameters in the images confirm that the tetragonal USb2 crystals cleave on the (001) basal plane as expected. Our calculations indicate a symmetric cut between Sb planes to be the most favorable cleavage plane and U atoms to be responsible for most of the density of states measured by STM. Since the spacing between Sb atoms and between U atoms is the same, STM topography alone cannot unambiguously identify the surface atom species.

Chen, Shao-ping [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

90

Diffusion in single crystals of melilite: 2. Cations  

SciTech Connect (OSTI)

Diffusion coefficients of divalent cations, Ni, Co, Fe, Mn, Ca, Sr, and Ba, in synthetic akermanite were determined by tracer-diffusion experiments. Diffusion coefficients of cation paris, Al + Al-Mg + Si, Al + Al-Co + Si, and Mg-Co in melilite solid-solution systems, were determined by coupled annealing of synthetic melilites of endmember compositions. Cobalt tracer diffuses slower along the c-crystallographic axis than along the a-axis by a factor of about three, possibly due to the anisotropic sheet-like arrangement of oxygen ions parallel to the (001) plane which is perpendicular to the c-axis in the crystal structure of melilite. In the coupled diffusion experiments, the cation pairs interdiffuse complementary, as expected for conservation of material and ionic charge balance in the substitution. The observed trend in the inter-diffusion coefficient vs. melting temperature relations is similar to those observed for alloys and consistent with an empirical rule for self-diffusion coefficient-melting temperature relation. In the diffusion coefficient vs. ionic radius diagram for divalent cation diffusion in akermanite, smooth curves were observed as in the case of olivine systems. However, the shapes of the curves were significantly different from those observed in olivine systems. The observed trend of diffusion coefficients with ionic radius can be explained on the basis of crystal structure-controlled diffusion in akermanite.

Morioka, Masana (Univ. of Tokyo Yayoi (Japan)); Nagasawa, Hiroshi (Gakushiun Univ. Mejiro, Tokyo (Japan))

1991-03-01T23:59:59.000Z

91

Induced crystallization of single-chain polyethylene on a graphite surface: Molecular dynamics simulation  

Science Journals Connector (OSTI)

Molecular dynamics (MD) simulations have been carried out on the crystallization of single-chain polyethylene (PE) which was adsorbed on a graphite (001) surface on one side and exposed to vacuum on the other at different temperatures. The MD simulation data have been analyzed to provide information about the crystallization process of polymer adsorbed on the solid substrate. The isothermal crystallization of PE proceeds in two steps: (1) adsorption and (2) orientation. The results detail the radial density distribution function, ordered parameters, local bond-orientational order parameters, and the local properties displayed in layers of the polymer parallel to the graphite and vacuum interfaces. It was also shown that the film thickness affected the critical crystallization temperature of the adsorbed polymer on the substrate surface. Furthermore, the influence of the graphite surface area on the crystallization of PE is discussed by comparing the crystallinity evolution of PE on graphite with different coverage.

Hua Yang (??); Xiao Jun Zhao (???); Miao Sun (??)

2011-07-14T23:59:59.000Z

92

Oscillatory Hall Effect, Magnetoresistance, and Magnetic Susceptibility of a Graphite Single Crystal  

Science Journals Connector (OSTI)

The Hall coefficient, magnetoresistance, and magnetic susceptibility of a graphite single crystal have been measured at liquid helium temperatures and in magnetic fields up to 25 kilogauss. All three phenomena are periodic functions of reciprocal field and exhibit the same period for like orientations of the crystal axes with respect to the magnetic field. The phases however are different. Where possible, experiment and theory have been compared.

Ted G. Berlincourt and M. C. Steele

1955-05-15T23:59:59.000Z

93

Thermographic analyses of the growth of Cd1-xZnxTe single crystals  

SciTech Connect (OSTI)

Bulk Cd1-xZnxTe (0single crystals for gamma-ray detectors are grown mainly from near-stoichiometric melts. We discuss the influence of the thermal pre-history of the melts (superheating, thermo-cycling, and cooling rate) on various physical properties based on our thermographic analyses, electrical conductivity and viscosity measurements. Increasing the Zn content causes non-monotonic dependencies in the quality of the crystals structure.

Kopach, O.V.; Bolotnikov, A.; Shcherbak, Larysa P.; Fochuk, Petro M.; and James, Ralph B.

2010-08-01T23:59:59.000Z

94

Coherence length of the KY(WO4)2 single crystal  

Science Journals Connector (OSTI)

The coherence scattering lengths of a KY(WO4)2 single crystal in the directions parallel and perpendicular to the growth directions were estimated from the broadening of X-ray reflections. Qualitative analysis of the shape of the diffracted peaks and the intensity distribution in reciprocal space maps indicated the presence of dislocations and volume defects, which introduced a negative dilation into the crystal host.

Shalimov, A.

2008-05-15T23:59:59.000Z

95

Single-Molecule Orientations in Dyed Salt Crystals Kristin L. Wustholz, Bart Kahr,* and Philip J. Reid*  

E-Print Network [OSTI]

Single-Molecule Orientations in Dyed Salt Crystals Kristin L. Wustholz, Bart Kahr,* and Philip J-1700 ReceiVed: June 7, 2005; In Final Form: July 8, 2005 We present single-molecule confocal microscopy is observed, demonstrating that single-molecule studies on mixed crystals need not be restricted

Reid, Philip J.

96

Physical properties of BeAl{sub 6}O{sub 10} single crystals  

SciTech Connect (OSTI)

Single crystals of BeAl{sub 6}O{sub 10}, beryllium hexaaluminate, were grown by the Czochralski method. The optical, acousto-optical, elastic, and a number of thermo-mechanical properties of bulk crystals of BeAl{sub 6}O{sub 10} were investigated in comparison with crystal of BeAl{sub 2}O{sub 4}, chrysoberyl. It has been demonstrated that this material is the promising host for active media of tunable solid state lasers. {copyright} {ital 1997 American Institute of Physics.}

Pestryakov, E.V.; Petrov, V.V.; Zubrinov, I.I.; Semenov, V.I.; Trunov, V.I.; Kirpichnikov, A.V. [Department of Quantum Electronics, Institute of Semiconductor Physics, Novosibirsk 630090 (Russia)] [Department of Quantum Electronics, Institute of Semiconductor Physics, Novosibirsk 630090 (Russia); Alimpiev, A.I. [Design and Technological Institute of Monocrystals, Novosibirsk 630058 (Russia)] [Design and Technological Institute of Monocrystals, Novosibirsk 630058 (Russia)

1997-10-01T23:59:59.000Z

97

Specific features of utilizing bismuth antimony chalcogenide single crystals in miniature coolers  

SciTech Connect (OSTI)

A procedure for growing perfect single crystals of bismuth antimony chalcogenide solid solutions by the Czochralski technique with melt feeding from a floating crucible was developed at the Baikov Institute of Metallurgy. Given that the single crystals in question readily split along the cleavage planes, the problem of acceptable yield of suitable products in the manufacture of thermoelements and cooling modules arises. To solve this problem, investigations were undertaken along two lines: (1) development of nondestructive, damage-free technologies; and (2) development of methods for making low-resistance antidiffusion contacts on the end faces of the thermoelements.

Semenyuk, V.A. [Odessa State Academy of Cold, (Ukraine); Ivanova, L.D.; Svechnikova, T.E. [Baikov Institute of Metallurgy, Moscow (Russian Federation)

1995-01-01T23:59:59.000Z

98

Poly(ethylene oxide) Crystallization in Single Walled Carbon Nanotube Based Nanocomposites: Kinetics and Structural Consequences  

SciTech Connect (OSTI)

The overall isothermal crystallization behavior of poly(ethylene oxide) (PEO) in single walled carbon nanotube (SWNT) based nanocomposites is studied with a focus on growth kinetics and morphological evolution of PEO using differential scanning calorimetry and in-situ small angle x-ray scattering measurements respectively. The characteristic time for crystallization of PEO increases due to the presence of lithium dodecyl sulfate (LDS) stabilized carbon nanotubes. Further, analysis of crystallization data using the Lauritzen-Hoffman regime theory of crystal growth shows the PEO chains stiffen in presence of LDS with an increased energy barrier associated with the nucleation and crystal growth, and the nanotubes further act as a barrier to chain transport or enhance the efficacy of the LDS action. The energy penalty and diffusional barrier to chain transport in the nanocomposites disrupt the crystalline PEO helical conformation. This destabilization leads to preferential growth of local nuclei resulting in formation of thinner crystal lamellae and suggests that the crystallization kinetics is strongly affected by the nucleation and crystal growth events. This study is particularly interesting considering the suppression of the PEO crystallinity in presence of small fraction of Lithium ion based surfactant and carbon nanotubes.

T Chatterjee; A Lorenzo; R Krishnamoorti

2011-12-31T23:59:59.000Z

99

Elasticity, strength, and toughness of single crystal silicon carbide, ultrananocrystalline diamond, and hydrogen-free tetrahedral amorphous  

E-Print Network [OSTI]

Elasticity, strength, and toughness of single crystal silicon carbide, ultrananocrystalline diamond carbide 3C-SiC , ultrananocrystalline diamond, and hydrogen-free tetrahedral amorphous carbon

Espinosa, Horacio D.

100

Synthesis and characterization of single-crystal indium nitride nanowires  

E-Print Network [OSTI]

in visible light range, and high-efficiency solar cells.2 Furthermore, InN has distinct advantages over Ga-solid (VLS) approach using a single-zone furnace at 500 °C,6 and a diameter distribution from 40 to 80 nm-zone furnace for InN nanowire synthe- sis. This technique allowed us to use a high-temperature zone (700 °C

Zhou, Chongwu

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Single crystal growth and characterization of nearly stoichiometric LiVO{sub 2}  

SciTech Connect (OSTI)

LiVO{sub 2} undergoes an imperfectly understood orbital ordering transition near 500 K resulting in a loss of magnetic moment below the transition. Studies of the transition have been hampered by a lack of high-quality stoichiometric single crystals. Here we report the growth and basic characterization of large, nearly stoichiometric LiVO{sub 2} single crystals. The crystals were characterized by magnetic susceptibility, electrical resistivity, differential scanning calorimetry, and specific heat measurements over a temperature range from 2 to 650 K. A first-order phase transition with large hysteresis near T{sub t}{approx}500 K was observed in all measurements. An anisotropy of the order of 100 was observed in the in-plane versus out-of-plane resistivity, and the inferred semiconducting energy gap was 0.18 eV for Tsingle crystals at temperatures below and above T{sub t}. Superlattice reflections were observed below T{sub t} and disappeared upon heating above the phase transition temperature. Upon cooling below T{sub t}, the supperlattice spots reappeared. Bright field electron micrographs indicate that the crystals develop a roughly hexagonal network of cracks.

Tian, W.; Chisholm, M.F.; Khalifah, P.G.; Jin, R.; Sales, B.C.; Nagler, S.E.; Mandrus, D

2004-07-02T23:59:59.000Z

102

Structures with three dimensional nanofences comprising single crystal segments  

DOE Patents [OSTI]

An article includes a substrate having a surface and a nanofence supported by the surface. The nanofence includes a multiplicity of primary nanorods and branch nanorods, each of the primary nanorods being attached to said substrate, and each of the branch nanorods being attached to a primary nanorods and/or another branch nanorod. The primary and branch nanorods are arranged in a three-dimensional, interconnected, interpenetrating, grid-like network defining interstices within the nanofence. The article further includes an enveloping layer supported by the nanofence, disposed in the interstices, and forming a coating on the primary and branch nanorods. The enveloping layer has a different composition from that of the nanofence and includes a radial p-n single junction solar cell photovoltaic material and/or a radial p-n multiple junction solar cell photovoltaic material.

Goyal, Amit; Wee, Sung-Hun

2013-08-27T23:59:59.000Z

103

A low-temperature sample orienting device for single crystal spectroscopy at the SNS  

SciTech Connect (OSTI)

A low temperature sample orientation device providing three axes of rotation has been successfully built and is in testing for use on several spectrometers at the spallation neutron source (SNS). Sample rotation about the vertical ({omega}) axis of nearly 360{sup o} and out of plane tilts ({phi} and {nu}) of from -3.4{sup o} to 4.4{sup o} and from -2.8{sup o} to 3.5{sup o}, respectively, are possible. An off-the-shelf closed cycle refrigerator (CCR) is mounted on a room temperature sealed rotary flange providing {omega} rotations of the sample. Out-of-plane tilts are made possible by piezoelectric actuated angular positioning devices mounted on the low temperature head of the CCR. Novel encoding devices based on magnetoresistive sensors have been developed to measure the tilt stage angles. This combination facilitates single crystal investigations from room temperature to 3.1 K. Commissioning experiments of the rotating CCR for both powder and single crystal samples have been performed on the ARCS spectrometer at the SNS. For the powder sample this device was used to continuously rotate the sample and thus average out any partial orientation of the powder. The powder rings observed in S(Q) are presented. For the single crystal sample, the rotation was used to probe different regions of momentum transfer (Q-space). Laue patterns obtained from a single crystal sample at two rotation angles are presented.

Bruce, Douglas R [ORNL; Gaulin, Bruce D. [McMaster University; Granroth, Garrett E [ORNL; Roberts II, Charles K [ORNL; Sherline, Todd E [ORNL; Solomon, Landon M [ORNL

2010-01-01T23:59:59.000Z

104

Modelling of high-temperature mechanical behaviour of a single crystal superalloy  

Science Journals Connector (OSTI)

...blade materials for modern gas turbines has been one of the most...of the squares of the residuals (SSR) between calculated...Here R again is the gas constant and A1, B1 and...on Single Crystals for Turbine Blades. Munich: MTU...

1997-01-01T23:59:59.000Z

105

Martensitic transformation in NiMnGa single crystals: Numerical simulation and experiments  

E-Print Network [OSTI]

is based on a detailed description of the stored energy. Furthermore, the energy dissipation due to phase microstructures in single crystals and the related energy dissipation can be predicted to some extent for SMAs. Let us name, without any ambitions for completeness, the models of Artemev et al. (2000), Falk

Arndt, Marcel

106

Bendable single crystal silicon thin film transistors formed by printing on plastic substrates  

E-Print Network [OSTI]

Bendable single crystal silicon thin film transistors formed by printing on plastic substrates E on plastic substrates using an efficient dry transfer printing technique. In these devices, free standing-Si is then transferred, to a specific location and with a controlled orientation, onto a thin plastic sheet

Rogers, John A.

107

Single-crystal x-ray diffraction of brucite to 14 GPa  

Science Journals Connector (OSTI)

Single-crystal brucite, Mg(OH)2, was studied to 14 GPa in a quasi-hydrostatic pressure medium using a diamond anvil cell and energy-dispersive synchrotron x-ray diffraction. The parameters of a third-order Birch-...

Thomas S. Duffy; Jinfu Shu; Ho-kwang Mao…

1995-07-01T23:59:59.000Z

108

ZnO Nanostructures Single-Crystal Hexagonal Disks and Rings of  

E-Print Network [OSTI]

ZnO Nanostructures Single-Crystal Hexagonal Disks and Rings of ZnO: Low-Temperature, Large of Chemistry University of New Orleans New Orleans, LA 70148 (USA) Fax: (+1)504-280-6860 E-mail: fli@uno.edu Dr to ellipsoids to disks, and even much more complex shapes, by adjusting experimental parameters,[33] we can

Wang, Zhong L.

109

Transport and superconducting properties of RNi2B2C (R=Y, Lu) single crystals  

E-Print Network [OSTI]

The in-plane resistivity, in-plane absolute thermopower, and upper critical held measurements are reported for single-crystal samples of YNi2B2C and LuNi2B2C superconductors. The in-plane resistivity shows metallic behavior and varies approximately...

Rathnayaka, KDD; Bhatnagar, AK; Parasiris, A.; Naugle, Donald G.

1997-01-01T23:59:59.000Z

110

Reduction of the trapping of positrons in dislocated single crystals of iron when charged with hydrogen  

SciTech Connect (OSTI)

The positron annihilation measurement was carried out with the pure iron single crystals deformed in various ways before and after hydrogen permeation. The positron trapping intensity was reduced more in the screw dislocation than in the edge dislocation by hydrogen charging. The trap occupancy by hydrogen was very close to the fraction of the reduction in positron trapping intensity.

Park, Y.K.; Waber, J.T.; Snead, C.L. Jr.

1985-01-01T23:59:59.000Z

111

Thermodynamics of strained vanadium dioxide single crystals Yijia Gu,1,a  

E-Print Network [OSTI]

Thermodynamics of strained vanadium dioxide single crystals Yijia Gu,1,a Jinbo Cao,2 Junqiao Wu,2 condition plays an important role. To investigate the strain contribution, a phenomenological thermodynamic films. In order to control and manipulate the MIT, it is necessary to understand the thermodynamics

Wu, Junqiao

112

Influence of water vapor pressure on the induction period during Li2SO4H2O single crystals dehydration  

E-Print Network [OSTI]

, lithium sulfate monohydrate 1. Introduction The decomposition reactions of solids, or reactions between of single crystals for the thermal dehydration of magnesium oxalate dihydrate [9] and zinc acetate dihydrate of the nucleation process, we have chosen the reaction of dehydration of lithium sulfate monohydrate single crystals

Paris-Sud XI, Université de

113

Polarized Neutron Studies on Antiferromagnetic Single Crystals: Technical Report No. 4  

DOE R&D Accomplishments [OSTI]

The theory of neutron scattering by magnetic crystals as given by Halpern and Johnson predicts changes in the polarization state of the neutron beam upon scattering which depend upon the relative orientation of the neutron polarization vector and the crystal magnetic axis. This was investigated experimentally with a polarized beam spectrometer using single crystals of Cr{sub 2}O{sub 3} and alpha - Fe{sub 2}O{sub 3} in which reside unique antiferromagnetic axes. Studies were made on several different reflections in both crystals for a number of different temperatures both below and above the Neel point. Results support the theoretical predictions and indicate directions for the moments in these crystals consistent with previous work. A more detailed study of the polarization changes in the (111) reflection in alpha - Fe{sub 2}O{sub 3} at room temperature on application of a magnetic field was carried out, The results indicate that the principal source of the parasitic ferromagnetism in hematite is essentially independent of the orientation of the antiferromagnetic domains within the crystal.

Nathans, R.; Riste, T.; Shirane, G.; Shull, C.G.

1958-11-26T23:59:59.000Z

114

Growth, Structure, and Magnetic Properties of CuFeTe{sub 2} Single Crystals  

SciTech Connect (OSTI)

CuFeTe{sub 2} single crystals were grown and the temperature dependence of their magnetic susceptibility in the temperature range 1.8-400 K was investigated. It is found that the magnetic susceptibility shows anomalies at temperatures T{sub s} = 65 and T{sub N} = 125 K. At T > 125 K, the crystal is in the paramagnetic state controlled by Fe{sup 2+} and Cu{sup 2+} ions with an effective magnetic moment of 1.44 {mu}B.

Dzhabbarov, A.I.; Orudzhev, S.K.; Guseinov, G.G.; Gakhramanov, N.F. [Institute of Physics, Academy of Sciences of Azerbaijan, pr. Dzhavida 33, Baku, 370143 (Azerbaijan)

2004-11-01T23:59:59.000Z

115

Study of photomodulated reflectance in 6H-SiC single crystals  

SciTech Connect (OSTI)

The effect of ultraviolet irradiation of the surface of silicon-carbide (6H-SiC) single crystals on their optical reflectivity in the visible and violet spectral regions is studied. It is shown that the photoreflection-signal intensity is maximal, if the light beam is incident at the Brewster angle and polarized parallel to the plane of incidence. The relative change induced in the refractive index of the surface layers of a crystal (10{sup -3}) upon exposure to nitrogen laser radiation, caused by the generation of nonequilibrium free charge carriers in the conduction band of the material, is established.

Gruzintsev, A. N., E-mail: gran@iptm.ru [Russian Academy of Sciences, Institute of Microelectronics Technology and Ultra-High-Purity Materials (Russian Federation)

2013-04-15T23:59:59.000Z

116

Gantmakher-Kaner oscillations at 79 GHz in single-crystal copper plates  

Science Journals Connector (OSTI)

Thin plates of high-purity, single-crystal copper have been investigated with the microwave transmission technique at 79 GHz with the utilization of a magnetic field perpendicular to the sample surfaces and parallel to the ?100?, ?110?, and ?111? crystal axes. The observed Gantmakher-Kaner oscillations are compared with a theoretical model first proposed by Phillips, Baraff, and Schmidt to explain their data in copper at 35 GHz for a ?100? orientation. With the aid of their model we find two classes of signals: (a) those arising from a sharp cutoff of the topological effectiveness, and (b) those due to an extremal helical trajectory. The generally excellent agreement between observation and the predictions of the model for all three crystal orientations confirms the physical significance of the model, although it is lacking a rigorous mathematical derivation.

T. M. Hsu and G. L. Dunifer

1983-07-15T23:59:59.000Z

117

Advances in the growth of alkaline-earth halide single crystals for scintillator detectors  

SciTech Connect (OSTI)

Alkaline-earth scintillators such as strontium iodide and other alkaline-earth halides activated with divalent europium represent some of the most efficient and highest energy resolution scintillators for use as gamma-ray detectors in a wide range of applications. These applications include the areas of nuclear nonproliferation, homeland security, the detection of undeclared nuclear material, nuclear physics and materials science, medical diagnostics, space physics, high energy physics, and radiation monitoring systems for first responders, police, and fire/rescue personnel. Recent advances in the growth of large single crystals of these scintillator materials hold the promise of higher crystal yields and significantly lower detector production costs. In the present work, we describe new processing protocols that, when combined with our molten salt filtration methods, have led to advances in achieving a significant reduction of cracking effects during the growth of single crystals of SrI2:Eu2+. In particular, we have found that extended pumping on the molten crystal-growth charge under vacuum for time periods extending up to 48 hours is generally beneficial in compensating for variations in the alkaline-earth halide purity and stoichiometry of the materials as initially supplied by commercial sources. These melt-pumping and processing techniques are now being applied to the purification of CaI2:Eu2+ and some mixed-anion europium-doped alkaline-earth halides prior to single-crystal growth by means of the vertical Bridgman technique. The results of initial studies of the effects of aliovalent doping of SrI2:Eu2+ on the scintillation characteristics of this material are also described.

Boatner, Lynn A [ORNL; Ramey, Joanne Oxendine [ORNL; Kolopus, James A [ORNL; Neal, John S [ORNL; Cherepy, Nerine [Lawrence Livermore National Laboratory (LLNL); Payne, Stephen A. [Lawrence Livermore National Laboratory (LLNL); Beck, P [Lawrence Livermore National Laboratory (LLNL); Burger, Arnold [Fisk University, Nashville; Rowe, E [Fisk University, Nashville; Bhattacharya, P. [Fisk University, Nashville

2014-01-01T23:59:59.000Z

118

Photoluminescence Polarization Anisotropy in a Single Heterostructured III-V Nanowire with Mixed Crystal Phases  

SciTech Connect (OSTI)

Low temperature (10 K) micro-photoluminescence ({mu}-PL) of single GaAs/AlGaAs core-shell nanowires with single GaAsSb inserts were measured. The PL emission from the zinc blende GaAsSb insert is strongly polarized along the nanowire axis while the PL emission from the wurtzite GaAs nanowire is perpendiculary polarized to the nanowire axis. The result indicates that the crystal phase, through the optical selection rules, has significant effect on the polarization of the PL from NWs besides the dielectric mismatch. The analysis of the PL results based on the electronic structure of these nanowires supports the correlation between the crystal phase and the PL emission.

Moses, A. F.; Hoang, T. B.; Ahtapodov, L.; Dheeraj, D. L.; Fimland, B. O.; Weman, H. [Department of Electronics and Telecommunications, Norwegian University of Science and Technology, NO - 7491 Trondheim (Norway); Helvoort, A. T. J. van [Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)

2011-12-23T23:59:59.000Z

119

Angle-resolved photoemission studies of single-crystal YBa2Cu3O7-x  

Science Journals Connector (OSTI)

We present the first angle-resolved photoemission and low-energy electron-diffraction (LEED) results obtained from clean single-crystal YBa2Cu3O7-x (001) surfaces prepared by cleaving in a vacuum. The surfaces exhibit (1×1)-ordered LEED patterns, but many of the photoemission features exhibit little or no angular dependence. The most important exception is the upper spectral edge, which shows angular dispersion and a strong photon energy dependence.

N. G. Stoffel; Y. Chang; M. K. Kelly; L. Dottl; M. Onellion; P. A. Morris; W. A. Bonner; G. Margaritondo

1988-05-01T23:59:59.000Z

120

Single crystal growth and superconductivity of Ca(Fe1-xCox)2As2  

SciTech Connect (OSTI)

We report the single crystal growth of Ca(Fe1-xCox)2As2 (0 <= x <= 0.082) from Sn flux. The temperature-composition phase diagram is mapped out based on the magnetic susceptibility and electrical transport measurements. Phase diagram of Ca(Fe1-xCox)2As2 is qualitatively different from those of Sr and Ba, it could be due to both the charge doping and structural tuning effects associated with Co substitution.

Hu, Rongwei; Ran, Sheng; Budko, Serguei; Straszheim, Warren E.; Canfield, Paul C.

2012-05-18T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
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121

Studies of Optical Damage in Photorefractive Single LiNbO3 Crystals using Imaging Polarimetry  

E-Print Network [OSTI]

The optical damage of photorefractive material, single LiNbO3 crystal, is experimentally studied. The specimen has been illuminated with the radiation of continuous Ar-laser (the wavelength of 488 nm) focused to 35?m spot. The induced birefringence map is obtained by means of imaging polarimeter. Promising resources of the experimental setup for detecting laser-induced damage in photorefractive materials is demonstrated.

Krupych, O; Vlokh, R

2005-01-01T23:59:59.000Z

122

Mo{sub 5}Si{sub 3} single crystals: Physical properties and mechanical behavior  

SciTech Connect (OSTI)

The materials processing, physical properties and mechanical behavior of an ultra-high temperature structural silicide, Mo{sub 5}Si{sub 3}, have been studied. High purity single crystals of Mo{sub 5}Si{sub 3} have been synthesized by both optical floating zone and Czochralski methods. The thermal and elastic properties of the MO{sub 5}Si{sub 3} single crystals were experimentally measured. Results show that Mo{sub 5}Si{sub 3} has significant thermal expansion anisotropy along the a and c directions with {alpha}{sub c}/{alpha}{sub a} = 2.2. Single crystal elastic moduli of Mo{sub 5}Si{sub 3} indicate that it has less elastic anisotropy and lower shear moduli than transition metal disilicides. Tensile stresses of up to 1.8 GPa can develop at grain boundaries after cooling from the melting point due to the thermal expansion mismatch in Mo{sub 5}Si{sub 3}, causing grain boundary cracking during processing of polycrystals. Room temperature Vickers indentation tests on (100) and (001) planes have been performed with different indenter diagonal orientations. The orientation dependence of hardness and fracture toughness of Mo{sub 5}Si{sub 3} single crystals have been obtained. The corresponding deformation and fracture modes have been revealed by microscopy studies. A comparison of Mo{sub 5}Si{sub 3} with other high temperature structural silicides, e.g., C11{sub b} and C40 transition metal disilicides, is discussed.

Chu, F.; Thoma, D.J.; McClellan, K.J.; Peralta, P.

1998-12-01T23:59:59.000Z

123

Effect of annealing on the electrical properties of thallium-doped PbTe single crystals  

SciTech Connect (OSTI)

It is found that electrical parameters of PbTe single crystals, the character of the dependences of these parameters on temperature and Tl impurity concentration, and the conductivity type (signs of {alpha} and R) are governed to a great extent by the temperature of preliminary annealing. The cause of this effect is that the concentration of doubly charged vacancies in the tellurium sublattice increases with an increase in the annealing temperature, as a result of which the formation of electrically neutral or singly charged complexes of impurity-vacancy type becomes more likely.

Ahmedova, G. A., E-mail: gulgunahmed@yahoo.com; Abdinova, G. J.; Abdinov, J. Sh. [National Academy of Sciences of Azerbaijan, Abdullaev Institute of Physics (Azerbaijan)

2011-02-15T23:59:59.000Z

124

Sum frequency generation (SFQ) vibrational spectroscopy studies of combustion reactions on platinum single crystal surfaces  

SciTech Connect (OSTI)

We have studied the dissociation of CO catalyzed by platinum single crystals. At 40 torr of CO, the Pt(111) crystal dissociates CO at 673 K. Under the same conditions, Pt(100) dissociates CO at 500 K, and Pt(557) dissociates CO at 548 K. Hence, the CO dissociation reaction is a structure sensitive reaction. SFG was used to monitor the CO top site resonance as the platinum crystals were heated to the dissociation temperature when exposed to 40 torr of CO. In all three systems, the CO resonance shifts to lower frequency as the platinum crystal is heated. However, the frequency of the CO resonance at the dissociation frequency is lower on the (100) and (111) crystal faces than on the Pt(557) crystal. We believe that the (111) and (100) crystal faces must undergo roughening to expose step or kink sites in order to facilitate the dissociation reaction. This is supported by UHV studies of CO dissociation catalyzed by platinum crystals. These studies observe dissociation only when step or kink sites are present. Since the Pt(111) surface is very stable, it needs to be heated to 673 K to produce the low coordination number sites needed for CO dissociation. Since the Pt(100) surface easily reconstructs, it is able to form the active sites for CO dissociation at relatively low temperatures. The SFG spectra support our conclusion that the CO molecules are sitting on low coordination number platinum atoms at the dissociation temperature. Since the Pt(557) surface already has step sites, the dissociation reaction can take place without further roughening of the surface. The CO resonance on the (557) crystal face at the dissociation temperature is at a very similar frequency to CO molecules adsorbed on only the step sites of the crystal. Further studies showed that the dissociation reaction takes place on the (557) surface at CO pressures as low as 1 torr. At 1 torr of CO, the carbon deposition rate is 1.0 x 10{sup -2} ML minute{sup -1}. A series of experiments at CO pressures ranging from 5 to 20 torr leads to a 0.8 order dependence of the dissociation reaction on CO pressure.

Gaughan, Jessica S.

2004-01-15T23:59:59.000Z

125

Thin Single Crystal Silicon Solar Cells on Ceramic Substrates: November 2009 - November 2010  

SciTech Connect (OSTI)

In this program we have been developing a technology for fabricating thin (< 50 micrometres) single crystal silicon wafers on foreign substrates. We reverse the conventional approach of depositing or forming silicon on foreign substrates by depositing or forming thick (200 to 400 micrometres) ceramic materials on high quality single crystal silicon films ~ 50 micrometres thick. Our key innovation is the fabrication of thin, refractory, and self-adhering 'handling layers or substrates' on thin epitaxial silicon films in-situ, from powder precursors obtained from low cost raw materials. This 'handling layer' has sufficient strength for device and module processing and fabrication. Successful production of full sized (125 mm X 125 mm) silicon on ceramic wafers with 50 micrometre thick single crystal silicon has been achieved and device process flow developed for solar cell fabrication. Impurity transfer from the ceramic to the silicon during the elevated temperature consolidation process has resulted in very low minority carrier lifetimes and resulting low cell efficiencies. Detailed analysis of minority carrier lifetime, metals analysis and device characterization have been done. A full sized solar cell efficiency of 8% has been demonstrated.

Kumar, A.; Ravi, K. V.

2011-06-01T23:59:59.000Z

126

Latent and active abPPO4 mushroom tyrosinase cocrystallized with hexatungstotellurate(VI) in a single crystal  

Science Journals Connector (OSTI)

Mushroom tyrosinase isoform abPPO4 (Agaricus bisporus polyphenol oxidase 4) was crystallized by means of an Anderson-type polyoxometalate. The enzyme crystallized as a crystallographic heterodimer containing the zymogen (L-TYR; 64 kDa), the 21 kDa smaller activated form (A-TYR) and the polyoxometalate (POM) within one single crystal in a 1:1:1 ratio.

Mauracher, S.G.

2014-08-29T23:59:59.000Z

127

Experimental and Theoretical Investigations of the NMR Line Shapes of LiF and NaF Single Crystals  

Science Journals Connector (OSTI)

Experimental cw line shapes have been obtained for Li7, Na23, and F19 nuclei in NaF and LiF single crystals, and compared with several line-shape theories. A new line-shape theory is described which gives better results than previous ones for these two crystal systems.

Ben T. Gravely and J. D. Memory

1971-05-15T23:59:59.000Z

128

Oxygen self-diffusion ``fast-paths'' in titanite single crystals and a general method for deconvolving self-diffusion  

E-Print Network [OSTI]

Oxygen self-diffusion ``fast-paths'' in titanite single crystals and a general method most other minerals, titanite rarely if ever forms perfect crystals. In addition to the point defects could occur. During the course of an experimental study of oxygen lattice diffusion in titanite, we

Watson, E. Bruce

129

X-ray detection capability of a BaCl{sub 2} single crystal scintillator  

SciTech Connect (OSTI)

The x-ray detection capability of a scintillation detector equipped with a BaCl{sub 2} single crystal was evaluated. The scintillation decay kinetics can be expressed by a sum of two exponential decay components. The fast and slow components have lifetimes of 1.5 and 85 ns, respectively. The total light output is 5% that of YAP:Ce. A subnanosecond timing resolution was obtained. The detection efficiency of a 67.41 keV x-ray is 87% for a detector equipped with a BaCl{sub 2} crystal 6-mm thick. Thus, excellent timing resolution and high detection efficiency can be simultaneously achieved. Additionally, luminescence decay characteristics under vacuum ultraviolet excitation have been investigated. Radiative decay of self-trapped excitons is thought to be responsible for the fast scintillation component.

Koshimizu, Masanori [Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai 9800-8579 (Japan); CREST, Japan Science and Technology Agency, Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Onodera, Kazuya; Asai, Keisuke [Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai 9800-8579 (Japan); Nishikido, Fumihiko [CREST, Japan Science and Technology Agency, Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Molecular Imaging Center, National Institute of Radiological Sciences, Anagawa 4-9-1, Inage-ku, Chiba 263-8555 (Japan); Haruki, Rie [CREST, Japan Science and Technology Agency, Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Advanced Scientific Research Center, Japan Atomic Energy Agency, Shirane, Shirakata, Tokai, Ibaraki 319-1155 (Japan); Shibuya, Kengo [CREST, Japan Science and Technology Agency, Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Institute of Physics, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan); Kishimoto, Shunji [CREST, Japan Science and Technology Agency, Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

2012-01-15T23:59:59.000Z

130

Positron annihilation in Al single crystals from 85 mK to 300K  

Science Journals Connector (OSTI)

Doppler-broadening and positron lifetime data have been taken for well annealed ultra-pure Al(110) crystals from 85 mK to 300K. The Doppler-broadening data are independent of specimen temperature from 85 mK to 77K, while they show an increase between 77K and 300K consistent with the linear slope observed previously by Hood and Schultz (1979). Over the whole temperature range studied, the Doppler data scale to the static thermal expansion coefficient. The lifetime data also show no obvious dependence on temperature over the entire range studied, although they were statistically limited by the cryostat geometry. These results, which represent the lowest temperatures studied by any positron annihilation technique, provide no evidence for positron localisation at low temperatures in very well annealed single crystals.

P J Schultz; A Vehanen; W Thomlinson; K G Lynn; I K MacKenzie

1983-01-01T23:59:59.000Z

131

Resonant stimulation of Raman scattering from single-crystal thiophene/phenylene co-oligomers  

SciTech Connect (OSTI)

Amplified Raman scattering was observed from single crystals of thiophene/phenylene co-oligomers (TPCOs). Under ns-pulsed excitation, the TPCO crystals exhibited amplified spontaneous emission (ASE) at resonant absorption wavelengths. With increasing excitation wavelength to the 0-0 absorption edge, the stimulated resonant Raman peaks appeared both in the 0-1 and 0-2 ASE band regions. When the excitation wavelength coincided with the 0-1 ASE band energy, the Raman peaks selectively appeared in the 0-2 ASE band. Such unusual enhancement of the 0-2 Raman scattering was ascribed to resonant stimulation via vibronic coupling with electronic transitions in the uniaxially oriented TPCO molecules.

Yanagi, Hisao, E-mail: yanagi@ms.naist.jp; Marutani, Yusuke; Matsuoka, Naoki; Hiramatsu, Toru; Ishizumi, Atsushi [Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan)] [Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Sasaki, Fumio [Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)] [Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Hotta, Shu [Department of Macromolecular Science and Engineering, Graduate School of Science and Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan)] [Department of Macromolecular Science and Engineering, Graduate School of Science and Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan)

2013-12-09T23:59:59.000Z

132

Synthesis and single crystal structure refinement of the one-layer hydrate of sodium brittle mica  

SciTech Connect (OSTI)

A sodium brittle mica with the ideal composition [Na{sub 4}]{sup inter}[Mg{sub 6}]{sup oct}[Si{sub 4}Al{sub 4}]{sup tet}O{sub 20}F{sub 4} was synthesized via melt synthesis in a gas tight crucible. This mica is unusual inasmuch as the known mica structure holds only room for two interlayer cations per unit cell and inasmuch as it readily hydrates despite the high layer charge while ordinary micas and brittle micas are non-swelling. The crystal structure of one-layer hydrate sodium brittle mica was determined and refined from single crystal X-ray data. Interlayer cations reside at the center of the distorted hexagonal cavities and are coordinated by the three inner basal oxygen atoms. The coordination of the interlayer cation is completed by three interlayer water molecules residing at the center of the interlayer region. The relative position of adjacent 2:1-layers thus is fixed by these octahedrally coordinated interlayer cations. Pseudo-symmetry leads to extensive twinning. In total five twin operations generate the same environment for the interlayer species and are energetically degenerate. - Graphical abstract: The sodium brittle mica has been successfully synthesized by melt synthesis and the crystal structure of the one-layer hydrate of sodium brittle mica was determined from single crystal X-ray diffraction data. Highlights: Black-Right-Pointing-Pointer Melt synthesis yielded coarse grained sodium brittle mica which showed little disorder. Black-Right-Pointing-Pointer Sodium brittle mica hydrated completely to the state of one-layer hydrate. Black-Right-Pointing-Pointer Structure of one-layer hydrate of sodium brittle mica could therefore be determined and refined. Black-Right-Pointing-Pointer Arrangement of upper and lower tetrahedral sheet encompassing interlayer cation were clarified.

Kalo, Hussein; Milius, Wolfgang [Lehrstuhl fuer Anorganische Chemie I, University of Bayreuth, D-95440 Bayreuth (Germany)] [Lehrstuhl fuer Anorganische Chemie I, University of Bayreuth, D-95440 Bayreuth (Germany); Braeu, Michael [BASF Construction Chemicals GmbH, 83308 Trostberg (Germany)] [BASF Construction Chemicals GmbH, 83308 Trostberg (Germany); Breu, Josef, E-mail: Josef.Breu@uni-bayreuth.de [Lehrstuhl fuer Anorganische Chemie I, University of Bayreuth, D-95440 Bayreuth (Germany)] [Lehrstuhl fuer Anorganische Chemie I, University of Bayreuth, D-95440 Bayreuth (Germany)

2013-02-15T23:59:59.000Z

133

Surface Structure Spread Single Crystals ((SC)-C-4): Preparation and characterization  

SciTech Connect (OSTI)

A set of six spherically curved Cu single crystals referred to as Surface Structure Spread Single Crystals (S{sup 4}Cs) has been prepared in such a way that their exposed surfaces collectively span all possible crystallographic surface orientations that can be cleaved from the face centered cubic Cu lattice. The method for preparing these S{sup 4}Cs and for finding the high symmetry pole point are described. Optical profilometry has been used to determine the true shapes of the S{sup 4}Cs and show that over the majority of the surface, the shape is extremely close to that of a perfect sphere. The local orientations of the surfaces lie within ±1{degree} of the orientation expected on the basis of the spherical shape; their orientation is as good as that of many commercially prepared single crystals. STM imaging has been used to characterize the atomic level structure of the Cu(111)±11{degree}-S{sup 4}C. This has shown that the average step densities and the average step orientations match those expected based on the spherical shape. In other words, although there is some distribution of step-step spacing and step orientations, there is no evidence of large scale reconstruction or faceting. The Cu S{sup 4}Cs have local structures based on the ideal termination of the face centered cubic Cu lattice in the direction of termination. The set of Cu S{sup 4}Cs will serve as the basis for high throughput investigations of structure sensitive surface chemistry on Cu.

de Alwis, A.; Holsclaw, B.; Pushkarev, V. V.; Reinicker, A.; Lawton, T. J.; Blecher, M. E.; Sykes, E. C. H.; Gellman, A. J.

2013-02-01T23:59:59.000Z

134

Single-crystal neutron diffraction studies on Ni-based metal-pnictide superconductor BaNi2As2  

SciTech Connect (OSTI)

We report the results of single-crystal neutron diffraction studies of the superconductor BaNi{sub 2}As{sub 2}. The experiments were performed on a tiny crystal of mass 0.8 mg at several temperatures between 20 and 200 K using the Single Crystal Diffractometer, SCD, at the Los Alamos Neutron Science Center. Above 130 K, BaNi{sub 2}As{sub 2} crystallizes in the tetragonal ThCr{sub 2}Si{sub 2} structure. Our neutron diffraction data corroborate a first-order structural transition around 130 K with a relatively large hysteresis of about 10K, in agreement with observations from bulk studies. The anisotropic thermal displacement coefficients are enhanced along c-axis approaching the transition, and a splitting is observed for in-plane type reflections below the transition, which is evidence for a change in crystal structure.

Kothapalli, Karunakar [Los Alamos National Laboratory; Ronning, F [Los Alamos National Laboratory; Bauer, E D [Los Alamos National Laboratory; Schultz, A J [Los Alamos National Laboratory; Nakotte, Heinz [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

135

A Computational Approach to Homogenizing Nickel-Based Single Crystal Alloys  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Computational Approach to Homogenizing Nickel-Based Computational Approach to Homogenizing Nickel-Based Single Crystal Alloys Contact NETL Technology Transfer Group techtransfer@netl.doe.gov May 2013 Significance * Provides significantly diminished processing costs, including reduced energy consumption and throughput times, and increased availability of capital equipment such as furnaces, due to shorter heat treatments * Generates superior Ni-based superalloys with improved performance in downstream applications * Provides extreme flexibility, allowing for modification to meet the differing constraints of individual production facilities and the level of homogenization desired

136

Electrical properties of PbTe single crystals with excess tellurium  

SciTech Connect (OSTI)

The effects of excess (up to 0.1 at %) Te atoms and heat treatment at 473 and 573 K for 120 h on the conductivity {sigma}, thermopower {alpha}, and Hall coefficient R of PbTe single crystals are studied. It is shown that excess Te atoms and annealing strongly affect the values and character of the temperature dependences of these parameters and the signs of {alpha} and R at low temperatures, which is caused by the acceptor effect of these atoms and the formation of antisite defects due to localization of Te in vacancies of the lead sublattice upon annealing.

Bagiyeva, G. Z., E-mail: bagieva-gjulandam@rambler.ru; Mustafayev, N. B.; Abdinova, G. Dj.; Abdinov, D. Sh. [National Academy of Sciences of Azerbaijan, Abdullaev Institute of Physics (Azerbaijan)

2011-11-15T23:59:59.000Z

137

The Resonance Scattering Phenomenon of Fast Negatively Charged Particles in a Single Crystal  

E-Print Network [OSTI]

The energy spectrum of the extended attractive potential of a crystallographic row for negatively charged particles has quasi-bound states. It follows that a negatively charged particle with small transversal momentum component ($p_{\\bot} R <<1$) may undergo resonance scattering. Thus the resonance scattering phenomenon can be observed in a single crystal, when fast electrons move with a small glancing angle ($\\theta_0 << 1/pR$) to a crystallographic axis. The calculated results for the electrons and angular widths of resonance peaks are consistent with experimental data.

Kovalev, Gennady V

2015-01-01T23:59:59.000Z

138

Electronic band structure imaging of three layer twisted graphene on single crystal Cu(111)  

SciTech Connect (OSTI)

Few layer graphene (FLG) is grown on single crystal Cu(111) by Chemical Vapor Deposition, and the electronic valence band structure is imaged by Angle-Resolved Photo-Emission Spectroscopy. It is found that graphene essentially grows polycrystalline. Three nearly ideal Dirac cones are observed along the Cu ?{sup ¯}K{sup ¯} direction in k-space, attributed to the presence of ?4° twisted three layer graphene with negligible interlayer coupling. The number of layers and the stacking order are compatible with Raman data analysis demonstrating the complementarity of the two techniques for a more accurate characterization of FLG.

Marquez Velasco, J. [National Center for Scientific Research “Demokritos,” 15310 Athens (Greece) [National Center for Scientific Research “Demokritos,” 15310 Athens (Greece); Department of Physics, National Technical University of Athens, Athens (Greece); Kelaidis, N.; Xenogiannopoulou, E.; Tsoutsou, D.; Tsipas, P.; Speliotis, Th.; Pilatos, G.; Likodimos, V.; Falaras, P.; Dimoulas, A., E-mail: dimoulas@ims.demokritos.gr [National Center for Scientific Research “Demokritos,” 15310 Athens (Greece); Raptis, Y. S. [Department of Physics, National Technical University of Athens, Athens (Greece)] [Department of Physics, National Technical University of Athens, Athens (Greece)

2013-11-18T23:59:59.000Z

139

Radiation-assisted Frenkel-Poole transport in single-crystal diamond  

SciTech Connect (OSTI)

The measurement of the density of occupied states as a function of the applied electric field, performed on single-crystal chemical vapour deposition diamond by x-ray modulated photocurrent technique, is reported. Two regimes of non-linear charge transport were observed: a classical Frenkel-Poole (FP) process at high electric fields (>6800 V/cm), and a radiation-assisted transport mechanism at intermediate electric fields (2000 to 6800 V/cm), consisting of a double-step process in which the direct re-emission into the extended band occurs following multiple photo-induced FP-like hopping transitions.

Girolami, M.; Bellucci, A.; Calvani, P.; Flammini, R.; Trucchi, D. M. [CNR-IMIP, Institute of Inorganic Methodologies and Plasmas, National Research Council, Via Salaria km 29.300, 00015 Monterotondo Stazione, Rome (Italy)] [CNR-IMIP, Institute of Inorganic Methodologies and Plasmas, National Research Council, Via Salaria km 29.300, 00015 Monterotondo Stazione, Rome (Italy)

2013-08-19T23:59:59.000Z

140

Magnetic field induced discontinuous spin reorientation in ErFeO{sub 3} single crystal  

SciTech Connect (OSTI)

The spin reorientation of ErFeO{sub 3} that spontaneously occurs at low temperature has been previously determined to be a process involving the continuous rotation of Fe{sup 3+} spins. In this work, the dynamic process of spin reorientation in ErFeO{sub 3} single crystal has been investigated by AC susceptibility measurements at various frequencies and static magnetic fields. Interestingly, two completely discontinuous steps are induced by a relatively large static magnetic field due to the variation in the magnetic anisotropy during this process. It provides deeper insights into the intriguing magnetic exchange interactions which dominate the sophisticated magnetic phase transitions in the orthoferrite systems.

Shen, Hui [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China) [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2500 (Australia); Cheng, Zhenxiang, E-mail: cheng@uow.edu.au; Hong, Fang; Wang, Xiaolin [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2500 (Australia)] [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2500 (Australia); Xu, Jiayue [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China)] [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); Yuan, Shujuan; Cao, Shixun [Department of Physics, Shanghai University, Shanghai 200444 (China)] [Department of Physics, Shanghai University, Shanghai 200444 (China)

2013-11-04T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

A new subunit of thermoelectric generator using single crystal-like elements of laminated type  

SciTech Connect (OSTI)

A compact subunit of thermoelectric generator is designed using single crystal-like 288 elements of (Bi,Sb){sub 2} (Te,Se){sub 3} compounds of laminated type. It is expected that the maximum power amounts to 17.3 (W) with 11.1 (A) and 1.56 (V) at the temperature difference of 50 {degree}C. The elements are prepared by the Bridgman method using a new type of crucible. Thermoelectric properties of these elements are measured using a simple Peltier technique. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Tanji, Y. [R& D Division, Tokin Corporation, Sendai, 982 (Japan); Nakagawa, Y. [Faculty of Engineering, Tohoku Institute of Technology, Sendai, 982 (Japan); Kaneko, T. [Institute for Materials Research, Tohoku University, Sendai, 980 (Japan); Ido, H.; Kuboki, M. [Faculty of Engineering, Tohoku Gakuin University, Tagajyo, 985 (Japan); Kogo, M. [R& D Division, Tokin Corporation, Sendai, 982 (Japan); Masumoto, T. [Institute for Materials Research, Tohoku University, Sendai, 980 (Japan); Sato, R. [Faculty of Engineering, Tohoku Gakuin University, Tagajyo, 985 (Japan)

1994-08-10T23:59:59.000Z

142

Far off-resonant coupling between photonic crystal microcavity and single quantum dot with resonant excitation  

SciTech Connect (OSTI)

In this paper, we experimentally demonstrate that with sub-nanowatt coherent s-shell excitation of a single InAs quantum dot, off-resonant coupling of 4.1?nm is possible between L3 photonic crystal microcavity and the quantum dot at 50?K. This resonant excitation reduces strongly the effect of surrounding charges to quantum dot, multiexciton complexes and pure dephasing. It seems that this far off-resonant coupling is the result of increased number of acoustical phonons due to high operating temperature of 50?K. The 4.1?nm detuning is the largest amount for this kind of coupling.

Banihashemi, Mehdi; Ahmadi, Vahid, E-mail: v-ahmadi@modares.ac.ir [Department of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, P.O. Box 14115-194 (Iran, Islamic Republic of)] [Department of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, P.O. Box 14115-194 (Iran, Islamic Republic of); Nakamura, Tatsuya; Kojima, Takanori; Kojima, Kazunobu; Noda, Susumu [Department of Electronic Science and Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)] [Department of Electronic Science and Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)

2013-12-16T23:59:59.000Z

143

The growth and characterization of LiGd?(Mo0?)? single crystals  

E-Print Network [OSTI]

and was used along with a thermo- electric heater/cooler. The DIP packaging technique also made the samples much more rugged and easier to handle (see figure 11). Figure 11 Holder III a) ceramic package, b) bonding pad, c) conductive high temperature... 1981 Major Subject: Electrical Engineering THE GROWTH AND CHARACTERIZATION OF LiGd (MoO ) SINGLE CRYSTALS A Thesis JAMES ALLYN REIMUND Approved as to style and content by: (R. K. Pandey, Cha~m . o Committee) )() (R. L. Geiger, Member) (T. W...

Reimund, James Allyn

1981-01-01T23:59:59.000Z

144

Single crystal oxide and oxide/oxide eutectic fibres for high temperature composites  

Science Journals Connector (OSTI)

The utilisation of fibre-reinforced metal, intermetallic and ceramic matrix composites (CMCs) in gas turbine engines offers the potential of improved fuel efficiency, higher operating temperature and greater thrust to weight ratio. The development of ceramic fibres with high strength, excellent strength retention at elevated temperatures and good creep resistance is essential to the successful implementation of composites in various high temperature components. Several single crystal oxide and oxide/oxide eutectic fibres have been developed to meet the demanding performance requirements. Recent progress made on developing these fibers will be discussed.

J.-M. Yang

2001-01-01T23:59:59.000Z

145

Crystal structure of La{sub 2}Mo{sub 2}O{sub 9} single crystals doped with bismuth  

SciTech Connect (OSTI)

Precision X-ray diffraction studies of La{sub 2-x}Bi{sub x}Mo{sub 2}O{sub 9} (x = 0.04, 0.06, and 0.18) single crystals are performed. It is found that in the compounds doped with bismuth, analogously with the structure of the metastable {beta}{sub ms} phase of pure La{sub 2}Mo{sub 2}O{sub 9} (LM), the La, Mo1, and O1 atoms deviate from the threefold axis on which they are located in the high-temperature {beta} phase. It is shown that bismuth atoms substitute for part of lanthanum atoms and occupy a position at the threefold axis in the neighborhood of the split lanthanum position. The implantation of bismuth atoms in the LM structure results in the return of a part of the molybdenum atoms to the position at the threefold axis. The occupancy of this position is equal to the occupancy of the bismuth atomic position.

Alekseeva, O. A., E-mail: olalex@ns.crys.ras.ru; Verin, I. A.; Sorokina, N. I.; Krasil'nikova, A. E. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Voronkova, V. I. [Moscow State University, Faculty of Physics (Russian Federation)

2010-07-15T23:59:59.000Z

146

Photonics and Nanostructures Fundamentals and Applications 2 (2004) 110 Modal behavior of single-line photonic crystal guiding  

E-Print Network [OSTI]

Photonics and Nanostructures ­ Fundamentals and Applications 2 (2004) 1­10 Modal behavior of single-line. Agiod,e, M. Kafesakif, C.M. Soukoulisd,f a CNRS/Laboratoire de Photonique et de Nanostructures, Route de of the transmission through single- missing-row photonic crystal (PC) straight guides, bends and combiners, fabricated

Soukoulis, Costas

147

Helium irradiation effects in polycrystalline Si, silica, and single crystal Si  

SciTech Connect (OSTI)

Transmission electron microscopy (TEM) has been used to investigate the effects of room temperature 6 keV helium ion irradiation of a thin ({approx_equal}55 nm thick) tri-layer consisting of polycrystalline Si, silica, and single-crystal Si. The ion irradiation was carried out in situ within the TEM under conditions where approximately 24% of the incident ions came to rest in the specimen. This paper reports on the comparative development of irradiation-induced defects (primarily helium bubbles) in the polycrystalline Si and single-crystal Si under ion irradiation and provides direct measurement of a radiation-induced increase in the width of the polycrystalline layer and shrinkage of the silica layer. Analysis using TEM and electron energy-loss spectroscopy has led to the hypothesis that these result from helium-bubble-induced swelling of the silicon and radiation-induced viscoelastic flow processes in the silica under the influence of stresses applied by the swollen Si layers. The silicon and silica layers are sputtered as a result of the helium ion irradiation; however, this is estimated to be a relatively minor effect with swelling and stress-related viscoelastic flow being the dominant mechanisms of dimensional change.

Abrams, K. J.; Greaves, G.; Berg, J. A. van den [Materials and Physics Research Centre, University of Salford, Salford (United Kingdom); Hinks, J. A.; Donnelly, S. E. [School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom); Pawley, C. J. [Materials and Physics Research Centre, University of Salford, Salford (United Kingdom); School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom); Eyidi, D. [Institut Pprime, Universite de Poitiers, Poitiers (France); Ward, M. B. [Institute for Materials Research, University of Leeds, Leeds (United Kingdom)

2012-04-15T23:59:59.000Z

148

Cooperative Island Growth of Large Area Single-Crystal Graphene by Chemical Vapor Deposition on Cu  

SciTech Connect (OSTI)

We describe a two-step approach for suppressing nucleation of graphene on Cu using chemical vapor deposition. In the first step, as received Cu foils are oxidized in air at temperatures up to 500 C to remove surface impurities and to induce the regrowth of Cu grains during subsequent annealing in H2 flow at 1040 C prior to graphene growth. In the second step, transient reactant cooling is performed by using a brief Ar pulse at the onset of growth to induce collisional deactivation of the carbon growth species. The combination of these two steps results in a three orders of magnitude reduction in the graphene nucleation density, enabling the growth of millimeter-size single crystal graphene grains. A kinetic model shows that suppressing nucleation promotes a cooperative island growth mode that favors the formation of large area single crystal graphene, and it is accompanied by a roughly 3 orders of magnitude increase in the reactive sticking probability of methane compared to that in random nucleation growth.

Regmi, Murari [Oak Ridge National Laboratory (ORNL); Rouleau, Christopher [Oak Ridge National Laboratory (ORNL); Puretzky, Alexander A [ORNL; Ivanov, Ilia N [ORNL; Geohegan, David B [ORNL; Chen, Jihua [ORNL; Eastman, Jeffrey [Argonne National Laboratory (ANL); Eres, Gyula [ORNL

2014-01-01T23:59:59.000Z

149

Diffraction Profiles of Elasticity Bent Single Crystals with Constant Strain Gradients  

SciTech Connect (OSTI)

This work presents a set of equations that can be used to predict the dynamical diffraction profile from a non-transparent single crystal with a constant strain gradient examined in Bragg reflection geometry with a spherical incident X-ray beam. In agreement with previous work, the present analysis predicts two peaks: a primary diffraction peak, which would have still been observed in the absence of the strain gradient and which exits the specimen surface at the intersection point of the incident beam with the sample surface, and a secondary (mirage) peak, caused by the deflection of the wavefield within the material, which exits the specimen surface further from this intersection point. The integrated intensity of the mirage peak increases with increasing strain gradient, while its separation from the primary reflection peak decreases. The directions of the rays forming the mirage peak are parallel to those forming the primary diffraction peak. However, their spatial displacement might cause (fictitious) angular shifts in diffractometers equipped with area detectors or slit optics. The analysis results are compared with experimental data from an Si single-crystal strip bent in cantilever configuration, and the implications of the mirage peak for Laue analysis and high-precision diffraction measurements are discussed.

Yan,H.; Kalenci, O.; Noyan, I.

2007-01-01T23:59:59.000Z

150

Dynamically controlling the emission of single excitons in photonic crystal cavities  

E-Print Network [OSTI]

Single excitons in semiconductor microcavities represent a solid-state and scalable platform for cavity quantum electrodynamics (c-QED), potentially enabling an interface between flying (photon) and static (exciton) quantum bits in future quantum networks. While both single-photon emission and the strong coupling regime have been demonstrated, further progress has been hampered by the inability to control the coherent evolution of the c-QED system in real time, as needed to produce and harness charge-photon entanglement. Here, using the ultrafast electrical tuning of the exciton energy in a photonic crystal (PhC) diode, we demonstrate the dynamic control of the coupling of a single exciton to a PhC cavity mode on a sub-ns timescale, faster than the natural lifetime of the exciton, for the first time. This opens the way to the control of single-photon waveforms, as needed for quantum interfaces, and to the real-time control of solid-state c-QED systems.

Francesco Pagliano; YongJin Cho; Tian Xia; Frank van Otten; Robert Johne; Andrea Fiore

2014-11-03T23:59:59.000Z

151

Dynamically controlling the emission of single excitons in photonic crystal cavities  

E-Print Network [OSTI]

Single excitons in semiconductor microcavities represent a solid-state and scalable platform for cavity quantum electrodynamics (c-QED), potentially enabling an interface between flying (photon) and static (exciton) quantum bits in future quantum networks. While both single-photon emission and the strong coupling regime have been demonstrated, further progress has been hampered by the inability to control the coherent evolution of the c-QED system in real time, as needed to produce and harness charge-photon entanglement. Here, using the ultrafast electrical tuning of the exciton energy in a photonic crystal (PhC) diode, we demonstrate the dynamic control of the coupling of a single exciton to a PhC cavity mode on a sub-ns timescale, faster than the natural lifetime of the exciton, for the first time. This opens the way to the control of single-photon waveforms, as needed for quantum interfaces, and to the real-time control of solid-state c-QED systems.

Pagliano, Francesco; Xia, Tian; van Otten, Frank; Johne, Robert; Fiore, Andrea

2014-01-01T23:59:59.000Z

152

Growth of Epitaxial gamma-Al2O3 Films on Rigid Single-Crystal Ceramic Substrates and Flexible, Single-Crystal-Like Metallic Substrates by Pulsed Laser Deposition  

SciTech Connect (OSTI)

Epitaxial -Al2O3 thin films were grown on diverse substrates using pulsed laser deposition. The high quality of epitaxial growth and cubic structure of -Al2O3 films was confirmed by x-ray diffraction. SrTiO3 and MgO single crystal substrates were used to optimize the growth conditions for epitaxial -Al2O3 film. Under the optimized conditions, epitaxial -Al2O3 thin films were grown on flexible, single-crystal-like, metallic templates. These included untextured Hastelloy substrates with a biaxially textured MgO layer deposited using ion-beam-assisted-deposition and biaxially textured Ni-W metallic tapes with epitaxially grown and a biaxially textured, MgO buffer layer. These biaxially textured, -Al2O3 films on flexible, single-crystal-like substrates are promising for subsequent epitaxial growth of various complex oxide films used for electrical, magnetic and electronic device applications.

Shin, Junsoo [ORNL; Goyal, Amit [ORNL; Wee, Sung Hun [ORNL

2009-01-01T23:59:59.000Z

153

Floating-zone growth and characterization of single crystals of cobalt orthosilicate, Co2SiO4  

Science Journals Connector (OSTI)

Good quality single crystals of high purity cobalt silicate, Co2SiO4, were successfully grown by the floating-zone method in air at atmospheric pressure along the three principle orientations. The grown crystals were 30–60 mm in length and 6–10 mm in diameter. Well developed facets were found on all crystals grown. Impurity levels and the degree of a desired excess of silicon in grown crystals were determined by using the ICP-AES technique. In addition, the presence of a small amount of inclusions in the matrix of grown crystals due to a small excess of silica was confirmed by TEM. Dislocation densities were determined upon etching; the observed densities were on the order of 105–106 cm?2.

Q. Tang; R. Dieckmann

2011-01-01T23:59:59.000Z

154

EPR investigation of defects in Bi12GeO20:Cr single crystal irradiated by high energy uranium ions  

E-Print Network [OSTI]

The results of investigations of EPR spectra of chromium doped $Bi_{12} GeO_{20} (BGO)$ single crystals are presented. The crystals were studied before and after irradiation by the $^{235}U$ ions with energy 9.47 MeV/u and fluency $5 \\cdot 10^{2} cm^{-2}$. The effect of heating irradiated samples in air on the EPR spectra is also studied.

Stefaniuk, I; Rogalska, I; Wróbel, D

2013-01-01T23:59:59.000Z

155

Radiation damage of polyethylene single crystals in electron microscopy between 1 and 2.5 MV. II. The influence of temperature  

E-Print Network [OSTI]

1043 Radiation damage of polyethylene single crystals in electron microscopy between 1 and 2.5 MV mécanismes réels décrits par les chimistes. Abstract. 2014 The critical dose measured for polyethylene single. Introduction. Polyethylene single crystals, like every organic sub- stance, lose their crystallinity when

Paris-Sud XI, Université de

156

First order phase transition and superconductivity in BaNi2As2 single crystals  

SciTech Connect (OSTI)

We report the synthesis and physical properties of single crystals of stoichiometric BaNi{sub 2}As{sub 2} which crystallizes in the ThCr{sub 2}Si{sub 2} structure type with lattice parameters a = 4.112(4) {angstrom} and c = 11.54(2) {angstrom}. Resistivity and heat capacity show a first order phase transition at T{sub 0} = 130 K with a thermal hysteresis of 7 K. The Hall coefficient is weakly temperature dependent from room temperature to 2 K where it has a value of -4 x 10{sup -10} {Omega}-cm/Oe. Resist.ivity, ac-susceptibility, and heat capacity find evidence for bulk superconductivity at T{sub c} = 0.7 K. The Sommerfeld coefficient at T{sub c} is 11.6 {+-} 0.9 mJ/ molK{sup 2}. The upper critical field is anisotropic with initial slopes of dH{sub c2}{sup c}/dT = -0.19 T/K and dH{sub c2}{sup ab}/dT = -0.40 T/K, as determined by resistivity.

Ronning, F [Los Alamos National Laboratory; Kurita, N [Los Alamos National Laboratory; Bauer, E D [Los Alamos National Laboratory; Scott, B L [Los Alamos National Laboratory; Park, T [Los Alamos National Laboratory; Klimczuk, T [Los Alamos National Laboratory; Movshovich, R [Los Alamos National Laboratory; Thompson, J D [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

157

Barium iron arsenide, barium cobalt arsenide, barium nickel arsenide single crystals and superconductivity upon cobalt doping  

SciTech Connect (OSTI)

The crystal structure and physical properties of BaFe{sub 2}As{sub 2}, BaCo{sub 2}As{sub 2}, and BaNi{sub 2}As{sub 2} single crystals are surveyed. BaFe{sub 2}As{sub 2} gives a magnetic and structural transition at T{sub N} = 132(1) K, BaCo{sub 2}As{sub 2} is a paramagnetic metal, while BaNi{sub 2}As{sub 2} has a structural phase transition at T{sub 0} = 131 K, followed by superconductivity below {Tc} = 0.69 K. The bulk superconductivity in Co-doped BaFe{sub 2}As{sub 2} below {Tc} = 22 K is demonstrated by resistivity, magnetic susceptibility, and specific heat data. In contrast to the cuprates, the Fe-based system appears to tolerate considerable disorder in the transition metal layers. First principles calculations for BaFe{sub 1.84}Co{sub 0.16}As{sub 2} inter-band scattering due to Co is weak.

Ronning, Filip [Los Alamos National Laboratory; Sefat, A S [ORNL; Mcguire, M M [ORNL; Sales, B [ORNL; Jin, R [ORNL; Mandrus, D [ORNL

2009-01-01T23:59:59.000Z

158

Single-crystal nanowires grown via electron-beam-induced deposition  

SciTech Connect (OSTI)

Electron-beam-induced deposition (EBID) is a useful technique for direct-writing of 3-dimensional dielectric, semiconductor, and metallic materials with nanoscale precision and resolution. The EBID process, however, has been limited in many cases because precursor byproducts (typically from organic precursors like W(CO)6) are incorporated into the deposited material resulting in contaminated and amorphous structures. In this manuscript, we have investigated the structure and composition of EBID tungsten nanostructures as-deposited from a tungsten hexafluoride (WF6) precursor. High-resolution transmission electron microscopy, electron diffraction and electron spectroscopy were employed to determine the effects that the electron beam scanning conditions have on the deposit characteristics. The results show that slow, one-dimensional lateral scanning produces textured -tungsten nanowire cores surrounded by an oxide secondary layer, while stationary vertical growth leads to single-crystal [100]-oriented W3O nanowires. Furthermore we correlate how the growth kinetics affect the resultant nanowire structure and composition.

Klein, Kate L [ORNL; Randolph, Steven J [ORNL; Fowlkes, Jason Davidson [ORNL; Allard Jr, Lawrence Frederick [ORNL; Meyer III, Harry M [ORNL; Simpson, Michael L [ORNL; Rack, Philip D [ORNL

2008-01-01T23:59:59.000Z

159

Single crystal growth and characterization of the large-unit-cell compound Cu13Ba  

SciTech Connect (OSTI)

Single crystals of Cu13Ba were successfully grown out of Ba–Cu self flux. Temperature dependent magnetization, M (T ), electrical resistivity, ?(T)?(T), and specific heat, Cp(T)Cp(T), data are reported. Isothermal magnetization measurements, M(H)M(H), show clear de Haas-van Alphen oscillations at T = 2 K for applied fields as low as View the MathML source?0H=1T. An anomalous behavior of the magnetic susceptibility is observed up to T ? 50 K reflecting the effect of de Haas-van Alphen oscillations at fairly high temperatures. The field- and temperature-dependencies of the magnetization indicate the presence of diluted magnetic impurities with a concentration of the order of 0.01 at.%. Accordingly, the minimum and lower temperature rise observed in the electrical resistivity at and below T = 15 K is attributed to the Kondo-impurity effect.

Jesche, Anton [Ames Laboratory; Budko, Serguei L. [Ames Laboratory; Canfield, Paul C. [Ames Laboratory

2013-10-31T23:59:59.000Z

160

Quantum Frequency Translation of Single-Photon States in Photonic Crystal Fiber  

E-Print Network [OSTI]

We experimentally demonstrate frequency translation of a nonclassical optical field via the Bragg scattering four-wave mixing process in a photonic crystal fiber (PCF). The high nonlinearity and the ability to control dispersion in PCF enable efficient translation between photon channels within the visible to-near-infrared spectral range, useful in quantum networks. Heralded single photons at 683 nm were translated to 659 nm with an efficiency of $28.6 \\pm 2.2$ percent. Second-order correlation measurements on the 683-nm and 659-nm fields yielded $g^{(2)}_{683}(0) = 0.21 \\pm 0.02$ and $g^{(2)}_{659}(0) = 0.19 \\pm 0.05$ respectively, showing the nonclassical nature of both fields.

H. J. McGuinness; M. G. Raymer; C. J. McKinstrie; S. Radic

2010-06-23T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Single-crystal sapphire tubes as economical probes for optical pyrometry in harsh environments  

SciTech Connect (OSTI)

One-end-sealed single-crystal sapphire tubes are presented as a simple, robust, and economical alternative for bulky lightpipe probes. Thermal radiation from a blackbody cavity created at the inner surface of the sealed end is gathered by a simple lens-based collecting system and transmitted via optical fiber to the remote detection unit. Simplicity and applicability of the concept are demonstrated by the combination of commercially available sapphire tubes with a common optical pyrometer. Radiation thermometers with sapphire tubes as invasive probes can be useful for applications requiring immunity to electromagnetic interference, resistance to harsh environments, simple replacement in the case of failure, and enhanced mechanical firmness, enabling wider range probe positioning inside the medium of interest.

Ruzicka, Jakub; Houzvicka, Jindrich; Bok, Jiri; Praus, Petr; Mojzes, Peter

2011-12-20T23:59:59.000Z

162

Surface Impedance Measurements of Single Crystal MgB2 Films for Radiofrequency Superconductivity Applications  

SciTech Connect (OSTI)

We report microstructure analyses and superconducting radiofrequency (SRF) measurements of large scale epitaxial MgB{sub 2} films. MgB{sub 2} films on 5 cm dia. sapphire disks were fabricated by a Hybrid Physical Chemical Vapor Deposition (HPCVD) technique. The electron-beam backscattering diffraction (EBSD) results suggest that the film is a single crystal complying with a MgB{sub 2}(0001) {parallel} Al{sub 2}O{sub 3}(0001) epitaxial relationship. The SRF properties of different film thicknesses (200 nm and 350 nm) were evaluated under different temperatures and applied fields at 7.4 GHz. A surface resistance of 9 {+-} 2 {mu}{Omega} has been observed at 2.2 K.

Binping Xiao, Xin Zhao, Joshua Spradlin, Charles Reece, Michael Kelley, Teng Tan, Xi Xiaoxing

2012-07-01T23:59:59.000Z

163

Deformation of Diopside Single Crystal at Mantle Pressure 2 TEM Characterization of Deformation Microstructures  

SciTech Connect (OSTI)

The dislocation microstructures of diopside single crystals deformed at high-pressure (4 {<=} P {<=} 9 GPa), high-temperature (1100{sup o} {<=} T {<=} 1400 {sup o}C) using a Deformation-DIA high-pressure apparatus (D-DIA) have been characterized by transmission electron microscopy using weak-beam dark-field (WBDF), precession electron diffraction (PED), large-angle convergent-beam electron diffraction (LACBED) and the thickness-fringe method. Dislocation glide is the dominant deformation mechanism under these conditions. The 1/2<110>{l_brace}110{r_brace} glide is controlled by lattice friction on the edge segments and shows extensive cross-slip. The [001] glide occurs mostly on {l_brace}110{r_brace}; no evidence for [001](010) glide has been found. The [100] dislocations bear a strong lattice friction probably due to complex (out of glide) core structures.

E Amiguet; P Cordier; P Raterron

2011-12-31T23:59:59.000Z

164

Antiferromagnetic spin excitations in single crystals of nonsuperconducting Li$_{1-x}$FeAs  

SciTech Connect (OSTI)

We use neutron scattering to determine spin excitations in single crystals of nonsuperconducting Li1 xFeAs throughout the Brillouin zone. Although angle resolved photoemission experiments and local density approximation calculations suggest poor Fermi surface nesting conditions for antiferromagnetic (AF) order, spin excitations in Li1 xFeAs occur at the AF wave vectors Q = (1,0) at low energies, but move to wave vectors Q = ( 0.5, 0.5) near the zone boundary with a total magnetic bandwidth comparable to that of BaFe2As2. These results reveal that AF spin excitations still dominate the low-energy physics of these materials and suggest both itinerancy and strong electron-electron correlations are essential to understand the measured magnetic excitations.

Wang, Meng [ORNL; Wang, X.C. [Beijing National Laboratory for Condensed Matter Physics/Chinese Academy of Scie; Abernathy, Douglas L [ORNL; Harriger, Leland W [ORNL; Luo, H.Q. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics; Zhao, Yang [ORNL; Lynn, J. W. [National Institute of Standards and Technology (NIST); Liu, Q.Q. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics; Jin, C.Q. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics; Fang, Chen [Purdue University; Hu, Jiangping [Purdue University and Chinese Academy of Sciences; Dai, Pengcheng [University of Tennessee, Knoxville (UTK)

2011-01-01T23:59:59.000Z

165

Thermal tunability in terahertz metamaterials fabricated on strontium titanate single crystal substrates  

E-Print Network [OSTI]

We report an experimental demonstration of thermal tuning of resonance frequency in a planar terahertz metamaterial consisting of a gold split-ring resonator array fabricated on a bulk single crystal strontium titanate (SrTiO3) substrate. Cooling the metamaterial starting from 409 K down to 150 K causes about 50% shift in resonance frequency as compare to its room temperature resonance, and there is very little variation in resonance strength. The resonance shift is due to the temperature-dependent refractive index (or the dielectric constant) of the strontium titanate. The experiment opens up avenues for designing tunable terahertz devices by exploiting the temperature sensitive characteristic of high dielectric constant substrates and complex metal oxide materials.

Singh, Ranjan; Jia, Q X; Taylor, Antoinette J; Chen, Hou-Tong

2011-01-01T23:59:59.000Z

166

Development of Single Crystal Chemical Vapor Deposition Diamonds for Detector Applications  

SciTech Connect (OSTI)

Diamond was studied as a possible radiation hard technology for use in future high radiation environments. With the commissioning of the LHC expected in 2010, and the LHC upgrades expected in 2015, all LHC experiments are planning for detector upgrades which require radiation hard technologies. Chemical Vapor Deposition (CVD) diamond has now been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of BaBar, Belle and CDF and is installed and operational in all LHC experiments. As a result, this material is now being discussed as an alternative sensor material for tracking very close to the interaction region of the super-LHC where the most extreme radiation conditions will exist. Our work addressed the further development of the new material, single-crystal Chemical Vapor Deposition diamond, towards reliable industrial production of large pieces and new geometries needed for detector applications.

Rainer Wallny

2012-10-15T23:59:59.000Z

167

Development of Single Crystal Chemical Vapor Deposition Diamonds for Detector Applications  

SciTech Connect (OSTI)

Diamond was studied as a possible radiation hard technology for use in future high radiation environments. With the commissioning of the LHC expected in 2009, and the LHC upgrades expected in 2013, all LHC experiments are planning for detector upgrades which require radiation hard technologies. Chemical Vapor Deposition (CVD) diamond has now been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of BaBar, Belle and CDF and is installed in all LHC experiments. As a result, this material is now being discussed as an alternative sensor material for tracking very close to the interaction region of the super-LHC where the most extreme radiation conditions will exist. Our work addressed the further development of the new material, single-crystal Chemical Vapor Deposition diamond, towards reliable industrial production of large pieces and new geometries needed for detector applications.

Harris Kagan; K.K. Gan; Richard Kass

2009-03-31T23:59:59.000Z

168

Photoacoustic investigation of transport in semiconductors: Theoretical and experimental study of a Ge single crystal  

Science Journals Connector (OSTI)

Photoacoustic (PA) heat-transmission measurements were used to study transport in a nearly intrinsic Ge single crystal. A theoretical model was developed which quantitatively describes excess carrier and thermal-wave space distributions, within the semiconductor under monochromatic cw modulated excitation. The PA heat-transmission, reflection, and photothermal-beam-deflection signals can be calculated using this model. It is shown that the frequency characteristic of the measurement system can be eliminated using measurements on different thicknesses of the same sample. It is also shown that both the normalized phase and amplitude spectra, as a function of the modulation frequency, can be used to determine the values of the thermal diffusivity, the excess-carrier lifetime, and the surface recombination velocity.

M. D. Drami?anin; P. M. Nikoli?; Z. D. Ristovski; D. G. Vasiljevi?; D. M. Todorovi?

1995-05-15T23:59:59.000Z

169

A co-crystal of polyoxometalates exhibiting single-molecule magnet behavior: the structural origin of a large magnetic anisotropy  

SciTech Connect (OSTI)

A polyoxometalate-based {MnIII3MnIV} single-molecule magnet exhibits a large axial anisotropy (D = ?0.86 cm?1) resulting from a near-parallel alignment of Jahn–Teller axes. Its rigorous three-fold symmetry (i.e. rhombicity E ? 0) and increased intercluster separation via co-crystallization effectively hamper quantum tunnelling of the magnetization. Graphical abstract: A co-crystal of polyoxometalates exhibiting single-molecule magnet behavior: the structural origin of a large magnetic anisotropy

Fang, Xikui; McCallum, Kendall; Pratt III, Harry D.; Anderson, Travis M.; Dennis, Kevin; Luban, Marshall

2012-03-29T23:59:59.000Z

170

Controlled Vapor Phase Growth of Single Crystalline, Two-Dimensional GaSe Crystals with High Photoresponse  

SciTech Connect (OSTI)

Abstract Compared with their bulk counterparts, atomically thin two-dimensional (2D) crystals exhibit new physical properties, and have the potential to enable next-generation electronic and optoelectronic devices. However, controlled synthesis of large uniform monolayer and multi-layer 2D crystals is still challenging. Here, we report the controlled synthesis of 2D GaSe crystals on SiO2/Si substrates using a vapor phase deposition method. For the first time, uniform, large (up to ~60 m in lateral size), single-crystalline, triangular monolayer GaSe crystals were obtained and their atomic resolution structure were characterized. The size, density, shape, thickness, and uniformity of the 2D GaSe crystals were shown to be controllable by growth duration, growth region, growth temperature, and argon carrier gas flow rate. The theoretical modeling of the electronic structure and Raman spectroscopy demonstrate a direct-to-indirect bandgap transition and progressive confinement-induced bandgap shifts for 2D GaSe crystals. The 2D GaSe crystals show p-type semiconductor characteristics and high photoresponsivity (~1.7 A/W under white light illumination) comparable to exfoliated GaSe nanosheets. These 2D GaSe crystals are potentially useful for next-generation electronic and optoelectronic devices such as photodetectors and field-effect transistors.

Li, Xufan [ORNL; Lin, Ming-Wei [ORNL; Zhang, Huidong [University of Tennessee, Knoxville (UTK); Puretzky, Alexander A [ORNL; Idrobo Tapia, Juan C [ORNL; Ma, Cheng [ORNL; Chi, Miaofang [ORNL; Yoon, Mina [ORNL; Rouleau, Christopher M [ORNL; Kravchenko, Ivan I [ORNL; Geohegan, David B [ORNL; Xiao, Kai [ORNL

2014-01-01T23:59:59.000Z

171

Magnetic-field induced absorption of zero-phonon lines in tris(bipyridine)ruthenium(2+) bis(hexafluorophosphate) and diperchlorate single crystals  

Science Journals Connector (OSTI)

Magnetic-field induced absorption of zero-phonon lines in tris(bipyridine)ruthenium(2+) bis(hexafluorophosphate) and diperchlorate single crystals ...

G. Hensler; E. Gallhuber; H. Yersin

1987-06-01T23:59:59.000Z

172

Superconductivity and Physical Properties of CaPd2Ge2 Single Crystals  

SciTech Connect (OSTI)

We present the superconducting and normal state properties of CaPd2Ge2 single crystals investigated by magnetic susceptibility ?, isothermal magnetization M, heat capacity Cp, in-plane electrical resistivity ? and London penetration depth ? versus temperature T and magnetic field H measurements. Bulk superconductivity is inferred from the ?(T) and Cp(T) data. The ?(T) data exhibit metallic behavior and a superconducting transition with Tc onset = 1.98 K and zero resistivity at Tc 0 = 1.67 K. The ?(T) reveals the onset of superconductivity at 2.0 K. For T > 2.0 K, the ?(T) and M(H) are weakly anisotropic paramagnetic with ?ab > ?c. The Cp(T) data confirm the bulk superconductivity below Tc = 1.69(3) K. The superconducting state electronic heat capacity is analyzed within the framework of a single-band ?-model of BCS superconductivity and various normal and superconducting state parameters are estimated. Within the ?-model, the Cp(T) data and the ab plane ?(T) data consistently indicate a moderately anisotropic s-wave gap with ?(0)/kBTc ? 1.6, somewhat smaller than the BCS value of 1.764. The relationship of the heat capacity jump at Tc and the penetration depth measurement to the anisotropy in the s-wave gap is discussed.

Anand, V K [Ames Laboratory; Kim, Hyunsoo [Ames Laboratory; Tanatar, Makariy A [Ames Laboratory; Prozorov, Ruslan [Ames Laboratory; Johnston, David C [Ames Laboratory

2014-10-08T23:59:59.000Z

173

Synthesis and single crystal x-ray diffraction study of a Schiff base derived from 4-acylpyrazolone and 2-aminophenol  

SciTech Connect (OSTI)

The title compound, (Z)-1-(3-chlorophenyl)-4[1((2hydroxyphenyl)amino)propylidene] -3-methyl-1H-pyrazol-5(4H)-one was synthesized by refluxing compound 1-(m-chlorophenyl)-3-methyl-4-propionyl-5-pyrazolone, with 2-aminophenol in ethanol. The compound crystallizes in the orthorhombic crystal system with space group Pca2{sub 1} having unit cell parameters: a = 26.2993(8), b = 7.0724(2) and c = 18.7170(5)Å. The structure contains two crystallographically independent molecules, A, and, B, in the asymmetric unit cell. The crystal structure was solved by direct method using single crystal X-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R- value of 0.049 for 5207 observed reflections.

Sharma, Naresh; Kant, Rajni, E-mail: vivek-gupta2k2@hotmail.com; Gupta, Vivek K., E-mail: vivek-gupta2k2@hotmail.com [Department of Physics and Electronics, University of Jammu, Jammu Tawi - 180006 (India); Jadeja, R. N. [Department of Chemistry, Faculty of Science, The M. S. University of Baroda, Vadodara-390002 (India)

2014-04-24T23:59:59.000Z

174

Pinning in twin boundaries of YBa sub 2 Cu sub 3 O sub 7-. delta. single crystals  

SciTech Connect (OSTI)

We present direct observation of Lorentz force induced flux motion and pinning by twin boundaries in single crystal YBa{sub 2}Cu{sub 3}O{sub 7 {minus}{delta}}. From AC magnetoresistance measurements, we derive the effective pinning potential attributed to twin boundaries. 7 refs., 3 figs.

Kwok, W.K.; Welp, U.; Vandervoort, K.G.; Crabtree, G.W. (Argonne National Lab., IL (USA)); Liu, J.Z. (California Univ., Davis, CA (USA). Dept. of Physics); Brooks, J.; Hettinger, J.; Hannahs, S.T. (Boston Univ., MA (USA). Dept. of Physics); Fleshler, S. (Argonne National Lab., IL (USA) Purdue Univ., Lafayette, IN (USA))

1990-01-01T23:59:59.000Z

175

Direct Laser Deposition of a Single-Crystal Ni3Al-Based IC221W Alloy  

E-Print Network [OSTI]

process based on laser cladding, which involves laser processing fine metallic powders into fully denseDirect Laser Deposition of a Single-Crystal Ni3Al-Based IC221W Alloy WEIPING LIU and J.N. Du221W alloy were produced on a SX Ni-base superalloy substrate by means of the laser-engineered net

DuPont, John N.

176

Density-functional study of organicinorganic hybrid single crystal ZnSe,,C2H8N2...12  

E-Print Network [OSTI]

January 2004 Unusual properties i.e., strong band dispersion, high carrier mobility, wide absorption-energy electric energy conversion are predicted to exist in the organic­inorganic chalcogenide single crystal Zn structures and exhibiting high carrier mobilities, as well as for possessing a variety of doping

Li, Jing

177

High power single-crystal fiber CW 946 nm laser and blue generation based on Rubidium-doped PPKTP  

E-Print Network [OSTI]

for high power, continuous wave and polarized laser at 946 nm (fig1.c). We demonstrate a polarized laser. Laurell, "High-power, continous-wave, second harmonic generation at 532 nm in periodically poled KTiOPO4(b)(a) (c) High power single-crystal fiber CW 946 nm laser and blue generation based on Rubidium

Boyer, Edmond

178

Patterned aluminum nanowires produced by electron beam at the surfaces of AlF3 single crystals  

E-Print Network [OSTI]

Patterned aluminum nanowires produced by electron beam at the surfaces of AlF3 single crystals C is demonstrated for fabricating patterned aluminum nanowires in AlF3 substrate in a scanning electron microscope nanowires of different sizes. The aluminum nanowires may act as nano- interconnects for nanoelectronics

Wang, Zhong L.

179

Vacancy hardening in single-crystal TiNx,,001... layers C.-S. Shin, D. Gall,a)  

E-Print Network [OSTI]

Vacancy hardening in single-crystal TiNx,,001... layers C.-S. Shin, D. Gall,a) N. Hellgren, J; accepted 27 February 2003 We investigate the effect of N vacancies on the mechanical properties are entirely due to anion vacancies. Hardness values increase continuously, while the elastic modulus decreases

Gall, Daniel

180

Spectroscopy of Charge Carriers and Traps in Field-Doped Single Crystal Organic Semiconductors  

SciTech Connect (OSTI)

The proposed research aims to achieve quantitative, molecular level understanding of charge carriers and traps in field-doped crystalline organic semiconductors via in situ linear and nonlinear optical spectroscopy, in conjunction with transport measurements and molecular/crystal engineering. Organic semiconductors are emerging as viable materials for low-cost electronics and optoelectronics, such as organic photovoltaics (OPV), organic field effect transistors (OFETs), and organic light emitting diodes (OLEDs). Despite extensive studies spanning many decades, a clear understanding of the nature of charge carriers in organic semiconductors is still lacking. It is generally appreciated that polaron formation and charge carrier trapping are two hallmarks associated with electrical transport in organic semiconductors; the former results from the low dielectric constants and weak intermolecular electronic overlap while the latter can be attributed to the prevalence of structural disorder. These properties have lead to the common observation of low charge carrier mobilities, e.g., in the range of 10-5 - 10-3 cm2/Vs, particularly at low carrier concentrations. However, there is also growing evidence that charge carrier mobility approaching those of inorganic semiconductors and metals can exist in some crystalline organic semiconductors, such as pentacene, tetracene and rubrene. A particularly striking example is single crystal rubrene (Figure 1), in which hole mobilities well above 10 cm2/Vs have been observed in OFETs operating at room temperature. Temperature dependent transport and spectroscopic measurements both revealed evidence of free carriers in rubrene. Outstanding questions are: what are the structural features and physical properties that make rubrene so unique? How do we establish fundamental design principles for the development of other organic semiconductors of high mobility? These questions are critically important but not comprehensive, as the nature of charge carriers is known to evolve as the carrier concentration increases, due to the presence of intrinsic disorder in organic semiconductors. Thus, a complementary question is: how does the nature of charge transport change as a function of carrier concentration?

Zhu, Xiaoyang

2014-12-10T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


181

Magnetic phase diagram of the S=1/2 triangular layered compound NaNiO2: a single crystal study  

E-Print Network [OSTI]

Magnetic phase diagram of the S=1/2 triangular layered compound NaNiO2: a single crystal study S de Magnetic Field Laboratory, CNRS, BP166, F-38042 Grenoble cedex 9, France Abstract. Using magnetic torque measurement on a NaNiO2 single crystal, we have established the magnetic phase diagram of this triangular

Boyer, Edmond

182

The Fabrication of an Inverter using Rubrene Single Crystal Organic Transistors C. Corbet, Y. Matsuoka, K. Watanabe, P.I. Yoshihiro Iwasa  

E-Print Network [OSTI]

The Fabrication of an Inverter using Rubrene Single Crystal Organic Transistors C. Corbet, Y single crystal devices. The purpose of this project is to fabricate an inverter device using organic by a physical vapor transport method with a nitrogen flow. Inverter devices were fabricated by laminating thus

Mellor-Crummey, John

183

Single Crystal Growth and Structural Characterization of a Novel Mixed-Valent Ternary Uranium Oxide, K8U7O24  

Science Journals Connector (OSTI)

Single crystals of K8U7O24 (K8U7.04O24) were grown out of a reactive potassium fluoride flux and characterized by single crystal X-ray diffraction. The reaction was carried out in a sealed copper tube. The title ...

Cory M. Read; Mark D. Smith; Hans-Conrad zur Loye

2014-12-01T23:59:59.000Z

184

In situ single-crystal to single-crystal (SCSC) transformation of the one-dimensional polymer catena-poly[[di­aqua(sulfato)copper(II)]-2-glycine] into the two-dimensional polymer poly[2-glycine-4-sulfato-copper(II)  

Science Journals Connector (OSTI)

On heating a crystal of the one-dimensional coordination polymer catena-poly[[diaqua(sulfato)copper(II)]-2-glycine] to 435 K in an oven, its aspect changed from blue to a very pale blue. Crystal structure analysis indicated that it had undergone a single-crystal to single-crystal (SCSC) solid-state transformation, losing two water mol­ecules and forming a two-dimensional coordination polymer, viz. poly[2-glycine-4-sulfato-copper(II)].

Stoeckli-Evans, H.

2014-10-15T23:59:59.000Z

185

Conductivity anisotropy in the doped Bi{sub 2}Te{sub 3} single crystals  

SciTech Connect (OSTI)

Temperature dependences (temperature range T = 0.5-300 K) of resistivity in the plane of layers and in the direction perpendicular to the layers, and the galvanomagnetic effects in undoped and doped Bi{sub 2}Te{sub 3} single crystals are studied (magnetic field H < 80 kOe, T = 0.5-4.2 K). It is shown that upon doping of Bi{sub 2}Te{sub 3} with the Group III atoms (In and B), conductivity anisotropy increases mainly due to an increase in resistivity in the direction perpendicular to the layers. This fact makes it possible to assume that the atoms of these impurities are incorporated mainly into the van der Waal gaps between the layers upon doping. It is also revealed that, upon doping of Bi{sub 2}Te{sub 3} with In and B, the temperature dependence of conductivity becomes weaker, which indicates an increase in the role of scattering by defects in scattering mechanisms. The concentrations and mobilities of charge carriers, values of the Hall factor conditioned by the anisotropy of effective masses and orientation of ellipsoids with respect to crystallographic axes, areas of the extreme section of the Fermi surface by the plane perpendicular to the direction of the magnetic field, and the Fermi energy are evaluated.

Abdullaev, N. A., E-mail: anadir@azintex.com; Kakhramanov, S. Sh.; Kerimova, T. G.; Mustafayeva, K. M. [Azerbaijan National Academy of Sciences, Institute of Physics (Azerbaijan); Nemov, S. A. [St. Petersburg State Polytechnical University (Russian Federation)

2009-02-15T23:59:59.000Z

186

Optical investigation of defects in semi-insulating Tl6I4S single crystals  

Science Journals Connector (OSTI)

Native defect levels in ternary compound Tl6I4S single crystals were studied by low-temperature photoluminescence (PL) and photoconductivity (PC) measurements. From the PL measurements, a broad emission band centered at 1.64 eV was observed at low temperatures. The peak can be decomposed using two standard Gaussian functions to reveal two emission bands at 1.55 and 1.66 eV. The PL peak at 1.55 eV is attributed to donor-acceptor pair recombination between a sulphur vacancy (VS) deep donor (Ed=0.57eV) and an antisite defect (SI) shallow acceptor (Ea=20meV). The 1.66-eV emission band is attributed to self-activated luminescence involving a defect complex and is described using a configuration coordinate model. Within this framework, the 1.66-eV emission band is associated with a S vacancy donor bound to a Tl vacancy acceptor that forms a VS?VTl Schottky pair. The photoconductivity spectra show the presence of a deep donor level located at 0.46 eV below the conduction-band edge, in good agreement with that measured by PL spectroscopy.

J. A. Peters; M. Sebastian; S. Nguyen; Zhifu Liu; Jino Im; A. J. Freeman; M. G. Kanatzidis; B. W. Wessels

2014-07-18T23:59:59.000Z

187

Advanced Undergraduate-Laboratory Experiment on Electron Spin Resonance in Single-Crystal Ruby  

Science Journals Connector (OSTI)

An electron-spin-resonance experiment which has been successfully performed in the advanced undergraduate laboratory at Rice University is described. In this experiment the ESR spectrum arising from Cr 3+ ions in a single-crystal synthetic ruby is studied. Both the positions and the intensities of the observable resonance lines are measured and the data are compared to the predictions of a theory based upon the use of a simple effective-spin Hamiltonian for the Cr 3+ ion. Although this experiment requires the use of apparatus not always available in undergraduate laboratories it involves measurements on a quantum-mechanical system whose behavior although far from trivial is nevertheless simple enough that the correspondence between observable physical quantities and their theoretically predicted values can be convincingly demonstrated. Since the student who undertakes this experiment can carry out himself all the measurements and perform for himself all the calculations required for interpretation of the experimental results the excellent agreement between the theory and the experiment is demonstrated for the student in a vivid fashion. The complete execution of the experiment including the full theoretical analysis of the problem is very helpful to the student in his attempt to grasp the significance of the many new quantum-mechanical quantities to which he is being exposed in his undergraduate studies.

Lee A. Collins; Michael A. Morrison; Paul L. Donoho

1974-01-01T23:59:59.000Z

188

Development of viable solutions for the synthesis of sulfur bearing single crystals  

SciTech Connect (OSTI)

The discovery of high temperature superconductivity in FeAs and FeSe based compounds has once again focused the condensed matter community on the need to systematically explore compounds containing chalcogens and pnictogens. Whereas some solution growth techniques have been developed to handle P and As, and Sb and Bi are versatile solvents in their own right, S has remained a problematic element to incorporate into conventional solution growth. To a large extent its low boiling point, combined with its polymeric nature in a molten state have made S an uninviting solvent. In this paper we present our development of a range of binary sulfur bearing solutions (some even sulfur rich) and demonstrate how we have been able to use these as useful starting points for the growth of a wide range of transition metal–sulfur–X ternary compounds. We present growth details and basic characterization data for Ni{sub 3}Bi{sub 2}S{sub 2}, Co{sub 3}Sn{sub 2}S{sub 2}, Fe{sub 2}GeS{sub 4}, CoSSb, and CePd{sub 3}S{sub 4}. In addition we present a remarkably simple method for the growth of single crystalline Co with crystallization taking place below the Curie temperature.

Lin, Xiao; Budko, Sergey; Canfield, Paul

2012-04-18T23:59:59.000Z

189

Evolution of the Surface Science of Catalysis from Single Crystals to Metal Nanoparticles under Pressure  

SciTech Connect (OSTI)

Vacuum studies of metal single crystal surfaces using electron and molecular beam scattering revealed that the surface atoms relocate when the surface is clean (reconstruction) and when it is covered by adsorbates (adsorbate induced restructuring). It was also discovered that atomic steps and other low coordination surface sites are active for breaking chemical bonds (H-H, O=O, C-H, C=O and C-C) with high reaction probability. Investigations at high reactant pressures using sum frequency generation (SFG)--vibrational spectroscopy and high pressure scanning tunneling microscopy (HPSTM) revealed bond breaking at low reaction probability sites on the adsorbate-covered metal surface, and the need for adsorbate mobility for continued turnover. Since most catalysts (heterogeneous, enzyme and homogeneous) are nanoparticles, colloid synthesis methods were developed to produce monodispersed metal nanoparticles in the 1-10 nm range and controlled shapes to use them as new model catalyst systems in two-dimensional thin film form or deposited in mesoporous three-dimensional oxides. Studies of reaction selectivity in multipath reactions (hydrogenation of benzene, cyclohexene and crotonaldehyde) showed that reaction selectivity depends on both nanoparticle size and shape. The oxide-metal nanoparticle interface was found to be an important catalytic site because of the hot electron flow induced by exothermic reactions like carbon monoxide oxidation.

Somorjai, Gabor A.; Park, Jeong Y.

2008-03-06T23:59:59.000Z

190

Precision control of thermal transport in cryogenic single-crystal silicon devices  

E-Print Network [OSTI]

We report on the diffusive-ballistic thermal conductance of multi-moded single-crystal silicon beams measured below 1 K. It is shown that the phonon mean-free-path $\\ell$ is a strong function of the surface roughness characteristics of the beams. This effect is enhanced in diffuse beams with lengths much larger than $\\ell$, even when the surface is fairly smooth, 5-10 nm rms, and the peak thermal wavelength is 0.6 $\\mu$m. Resonant phonon scattering has been observed in beams with a pitted surface morphology and characteristic pit depth of 30 nm. Hence, if the surface roughness is not adequately controlled, the thermal conductance can vary significantly for diffuse beams fabricated across a wafer. In contrast, when the beam length is of order $\\ell$, the conductance is dominated by ballistic transport and is effectively set by the beam area. We have demonstrated a uniformity of $\\pm$8% in fractional deviation for ballistic beams, and this deviation is largely set by the thermal conductance of diffuse beams tha...

Rostem, Karwan; Colazo, Felipe A; Crowe, Erik J; Denis, Kevin L; Lourie, Nathan P; Moseley, Samuel H; Stevenson, Thomas R; Wollack, Edward J

2014-01-01T23:59:59.000Z

191

Method of bonding single crystal quartz by field-assisted bonding  

DOE Patents [OSTI]

The method of producing a hermetic stable structural bond between quartz crystals includes providing first and second quartz crystals and depositing thin films of borosilicate glass and silicon on portions of the first and second crystals, respectively. The portions of the first and second crystals are then juxtaposed in a surface contact relationship and heated to a temperature for a period sufficient to cause the glass and silicon films to become electrically conductive. An electrical potential is then applied across the first and second crystals for creating an electrostatic field between the adjoining surfaces and causing the juxtaposed portions to be attracted into an intimate contact and form a bond for joining the adjoining surfaces of the crystals.

Curlee, Richard M. (Tijeras, NM); Tuthill, Clinton D. (Edgewood, NM); Watkins, Randall D. (Albuquerque, NM)

1991-01-01T23:59:59.000Z

192

Spontaneous Emission ß-factors in Photonic Crystal Waveguides: Towards Single-Mode LED  

Science Journals Connector (OSTI)

We theoretically study light emission in photonic crystal waveguides and show that remarkably large spontaneous emission rates into the fundamental guided mode (beta factor >95%)...

Lecamp, Guillaume; Sauvan, Christophe; Lalanne, Philippe; Hugonin, Jean-Paul

193

Thermal oxidation of single crystal aluminum antimonide and materials having the same  

DOE Patents [OSTI]

In one embodiment, a method for forming a non-conductive crystalline oxide layer on an AlSb crystal includes heat treating an AlSb crystal in a partial vacuum atmosphere at a temperature conducive for air adsorbed molecules to desorb, surface molecule groups to decompose, and elemental Sb to evaporate from a surface of the AlSb crystal and exposing the AlSb crystal to an atmosphere comprising oxygen to form a crystalline oxide layer on the surface of the AlSb crystal. In another embodiment, a method for forming a non-conductive crystalline oxide layer on an AlSb crystal includes heat treating an AlSb crystal in a non-oxidizing atmosphere at a temperature conducive for decomposition of an amorphous oxidized surface layer and evaporation of elemental Sb from the AlSb crystal surface and forming stable oxides of Al and Sb from residual surface oxygen to form a crystalline oxide layer on the surface of the AlSb crystal.

Sherohman, John William; Yee, Jick Hong; Coombs, III, Arthur William; Wu, Kuang Jen J.

2012-12-25T23:59:59.000Z

194

X-ray dynamical diffraction from single crystals with arbitrary shape and strain field: A universal approach to modeling  

Science Journals Connector (OSTI)

The effects of dynamical diffraction in single crystals engender many unique diffraction phenomena that cannot be interpreted by the kinematical-diffraction theory, yet knowledge of them is vital to resolving a vast variety of scientific problems ranging from crystal optics to strain measurements in crystalline specimens. Although the fundamental dynamical-diffraction theory was established decades ago, modeling it remains a challenge in a general case wherein the crystal has complex boundaries and mixed diffraction geometries (Bragg or Laue). Here, we propose a universal approach for modeling x-ray dynamical diffraction from a single crystal with arbitrary shape and strain field that is based on the integral representation of the Takagi-Taupin equations. Using it, we can construct the solution iteratively via a converging series, independent of the diffraction geometry. Moreover, the integral equations offer additional insights into the diffraction physics that are not readily apparent in its differential counterparts. To demonstrate this approach, we studied the dynamical diffraction from a slab of single crystal with both Bragg and Laue diffraction excited on the entrance boundaries, a problem that is difficult to model by other methods. We also explored the mirage effect caused by the presence of a linear strain field and compared it to the Eikonal theory. Lastly, we derived a dynamical-diffraction equation correlating the structural properties of a particle to its far-field Bragg-diffraction pattern, shedding light on how dynamical diffraction affects these kinematical-diffraction-based inverse techniques for reconstructing the shape and the strain field.

Hanfei Yan and Li Li

2014-01-07T23:59:59.000Z

195

TEM and x-ray investigation of single crystal-like zirconia films fabricated by dual ion beam deposition  

SciTech Connect (OSTI)

Single crystal-like yttria-stabilized zirconia (YSZ) thin films have been deposited on amorphous quartz, polycrystalline zirconia, single crystal Si, and Hastelloy substrates using dual ion beam deposition (IBAD). These films are highly crystallographically aligned both normal to and within the film plane. The films are deposited at low substrate temperatures (< 200 C), and the film orientation is substrate independent. 0--20 X-ray diffraction, X-ray rocking curves, X-ray pole figures and X-ray phi scans are used to evaluate the film structure. High resolution cross-sectional TEM is used to examine the evolution of crystallographic film alignment on an amorphous quartz substrate. The data suggest that the evolution of biaxial alignment is nucleation controlled under these conditions.

Ressler, K.G.; Sonnenberg, N.; Cima, M.J. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Ceramics Processing Research Lab.

1996-12-31T23:59:59.000Z

196

Influence of composition on microstructural parameters of single crystal nickel-base superalloys  

SciTech Connect (OSTI)

Fourteen nickel-base superalloy single crystals containing a range of chromium (Cr), cobalt (Co), molybdenum (Mo), and rhenium (Re) levels, and fixed amounts of aluminum (Al) and tantalum (Ta), were examined to determine the effect of bulk composition on basic microstructural parameters, including {gamma} Prime solvus, {gamma} Prime volume fraction, topologically close-packed (TCP) phases, {gamma} and {gamma} Prime phase chemistries, and {gamma}-{gamma} Prime lattice mismatch. Regression models describing the influence of bulk alloy composition on each of the microstructural parameters were developed and compared to predictions by a commercially-available software tool that used computational thermodynamics. Co produced the largest change in {gamma} Prime solvus over the wide compositional range explored and Mo produced the biggest effect on the {gamma} lattice parameter over its range, although Re had a very potent influence on all microstructural parameters investigated. Changing the Cr, Co, Mo, and Re contents in the bulk alloy had an impact on their concentrations in the {gamma} matrix and to a smaller extent in the {gamma} Prime phase. The software tool under-predicted {gamma} Prime solvus temperatures and {gamma} Prime volume fractions, and over-predicted TCP phase volume fractions at 982 Degree-Sign C. However, the statistical regression models provided excellent estimations of the microstructural parameters and demonstrated the usefulness of such formulas. - Highlights: Black-Right-Pointing-Pointer Effects of Cr, Co, Mo, and Re on microstructure in new low density superalloys Black-Right-Pointing-Pointer Co produced a large change in {gamma} Prime solvus; Mo had a large effect on lattice mismatch. Black-Right-Pointing-Pointer Re exhibited very potent influence on all microstructural parameters was investigated. Black-Right-Pointing-Pointer {gamma} and {gamma} Prime phase chemistries both varied with temperature and alloy composition. Black-Right-Pointing-Pointer Computational thermodynamic modeling tool did not accurately predict microstructure.

MacKay, R.A., E-mail: Rebecca.A.MacKay@nasa.gov [NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, Ohio 44135 (United States); Gabb, T.P. [NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, Ohio 44135 (United States); Garg, A. [NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, Ohio 44135 (United States); University of Toledo, 2801 W. Bancroft, Toledo, Ohio 43606 (United States); Rogers, R.B.; Nathal, M.V. [NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, Ohio 44135 (United States)

2012-08-15T23:59:59.000Z

197

Combined Investigation of Water Sorption on TiO2 Rutile (110) Single Crystal Face: XPS vs. Periodic DFT  

E-Print Network [OSTI]

1 Combined Investigation of Water Sorption on TiO2 Rutile (110) Single Crystal Face: XPS vs(0)169157150; e-mail: roques@ipno.in2p3.fr Keywords: water, sorption, rutile TiO2, (110), XPS, DFT. Abstract XPS and periodic DFT calculations have been used to investigate water sorption on the TiO2 rutile (110) face. Two

Paris-Sud XI, Université de

198

Electrical Effects associated with the Mechanical Deformation of Single Crystals of Alkali Halides  

Science Journals Connector (OSTI)

... 0-5 cm. in size cleaved from the crystals. The larger opposite faces were roughened with emery paper, and colloidal graphite was painted on to serve as an electrode, ...

J. E. CAFFYN; T. L. GOODFELLOW

1955-11-05T23:59:59.000Z

199

Mechanism-based constitutive modeling of L1? single-crystal plasticity  

E-Print Network [OSTI]

Ni3Al, an L12 structure intermetallic crystal, is the basic composition of the [gamma]' precipitates in nickel-based superalloys and is a major strengthening mechanism contributing to the superalloys' outstanding ...

Yin, Yuan, 1977-

2006-01-01T23:59:59.000Z

200

E-Print Network 3.0 - anthracene single crystals Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

coated with phenanthrene crystals. The agar contained, per litre of dH2O: 15 g bacto-agar, 1 g Source: Daugulis, Andrew J. - Department of Chemical Engineering, Queen's...

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

A Nano-Quantum Photonic Model for Justification of Dispersion in Single Crystal Film of NPP  

E-Print Network [OSTI]

In this paper, we present a nano-quantum photonic model for justification of normal dispersion in a thin crystal film of NPP. In this method, we assume a laser beam consists of a flow of energetic particles. By precise analyzing of photon interaction with pi-electron system of benzene ring in NPP crystal, we will attain refractive index (RI) in any wavelength and compare the results with experimental data.

Hassan Kaatuzian; AliAkbar Wahedy Zarch

2006-11-28T23:59:59.000Z

202

Anharmonicity and isomorphic phase transition: a multi-temperature X-ray single-crystal and powder diffraction study of 1-(2'-aminophenyl)-2-methyl-4-nitroimidazole  

Science Journals Connector (OSTI)

Multi-temperature single-crystal and powder diffraction experiments on 1-(2'-aminophenyl)-2-methyl-4-nitroimidazole show that this crystal undergoes an isomorphic phase transition with the coexistence of two phase domains over a wide temperature range. The anharmonic approach was the only way to model the resulting disorder.

Poulain, A.

2014-02-28T23:59:59.000Z

203

Specific features of the effect of irradiation with electrons and neutrons on photoelectric properties of CdS single crystals nominally undoped and doped with Cu  

Science Journals Connector (OSTI)

Electrical, photoelectric, and magnetic properties of CdS single crystals undoped and doped with copper (N Cu ? 1018 cm?3) and irradiated with electrons (E = 1.2 MeV, ? = 2 × 1017 cm?2) and neutro...

H. Ye. Davidyuk; V. V. Bozhko; L. V. Bulatetska

2008-10-01T23:59:59.000Z

204

Structure of high-temperature nickel alloy ZhS36VI for single-crystal blades of high-pressure turbines  

Science Journals Connector (OSTI)

The fine structure, phase composition, and segregation inhomogeneity of carbonless single-crystal rhenium-alloyed alloy ZhS36VI in cast and heat-treated conditions are studied. The structural and phase stabili...

V. P. Kuznetsov; V. P. Lesnikov; E. V. Moroz…

2008-03-01T23:59:59.000Z

205

Dielectric, hypersonic, and domain anomalies of ,,PbMg13Nb23O3...1x,,PbTiO3...x single crystals  

E-Print Network [OSTI]

Dielectric, hypersonic, and domain anomalies of ,,PbMg1Ã?3Nb2Ã?3O3...1Ã?x,,PbTiO3...x single crystals

206

Excited-state absorption and 1064-nm end-pumped laser emission of Nd:YVO4 single-crystal fiber grown by laser-heated pedestal growth  

Science Journals Connector (OSTI)

We present an investigation of the excited-state absorption and laser emission of a 1.0-at.%-Nd3+ -doped YVO4 single-crystal fiber grown by the low-cost and...

de Camargo, Andrea S S; Nunes, Luiz Antonio O; Ardila, Diogenes R; Andreeta, José Pedro

2004-01-01T23:59:59.000Z

207

Luminescent Study of Recombination Processes in the Single-Crystal Silicon and Silicon Structures Fabricated Using High-Efficiency Solar Cell Technology  

Science Journals Connector (OSTI)

Some results of the author’s researches in the last decade of the luminescence in the region of the fundamental absorption edge (edge luminescence) of the single-crystal silicon (c-Si), including structures which...

A. M. Emel’yanov

2014-01-01T23:59:59.000Z

208

Scanning Josephson Tunneling Microscopy of Single Crystal Bi2Sr2CaCu2O8+delta with a Conventional Superconducting Tip  

E-Print Network [OSTI]

materials in the Josephson junction where, Ic is theYBCO) single crystal Josephson junctions can be explained byfor Pb/I/Pb STM Josephson junctions near zero bias with

Kimura, H.

2010-01-01T23:59:59.000Z

209

Large sensitive-area NbN nanowire superconducting single-photon detectors fabricated on single-crystal MgO substrates  

SciTech Connect (OSTI)

We report on the performance of large area NbN nanowire superconducting single-photon detectors (SSPDs). 20x20 {mu}m{sup 2} area SSPDs with 80 and 100 nm linewidths and 50% fill factor were fabricated in 4-nm-thick NbN films grown on single-crystal MgO substrates. The high quality of the devices was verified by electrical and optical testing and compares favorably to measurements of 10x10 {mu}m{sup 2} area SSPDs. Measurements of kinetic inductance versus bias current indicate that the constriction density is low. The fiber-coupled detection efficiency of the devices was 0.4%-3.5% at 100 Hz dark count rate.

Miki, Shigehito; Fujiwara, Mikio; Sasaki, Masahide; Wang Zhen [National Institute of Information and Communications Technology, 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795 (Japan); Baek, Burm; Nam, Sae Woo [National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305 (United States); Miller, Aaron J. [Department of Physics and Astronomy, Albion College 611 East Porter Street, Albion, Michigan 49224 (United States); Hadfield, Robert H. [School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS (United Kingdom)

2008-02-11T23:59:59.000Z

210

Chain-oxygen ordering in twin-free YBa2Cu3O7-single crystals driven by 20-keV electron irradiation  

E-Print Network [OSTI]

Chain-oxygen ordering in twin-free YBa2Cu3O7- single crystals driven by 20-keV electron irradiation 2005 We have examined the effects of 20-keV electron irradiation on the -Cu 1 -O 1 - n chain-oxygen arrange- ments in oxygen-deficient but otherwise twin-free YBa2Cu3O7- single crystals. Comparison

Johansen, Tom Henning

211

Photoconductivity and luminescence of CuInSe{sub 2} single crystals at a high level of optical excitation  

SciTech Connect (OSTI)

The luminance-current and spectral characteristics of photoluminescence of the CuInSe{sub 2} single crystals are studied. The superlinear portion of the excitation-intensity dependence of photoconductivity at low excitation intensities in compensated p-CuInSe{sub 2} crystals is explained on the basis of a recombination model. The emission band that peaked at 0.98 eV in the n-CuInSe{sub 2} photoluminescence spectrum corresponds to radiative recombination of electrons at the donor level with a depth of 0.04 eV. The maximum in the band intensity corresponds to the energy gap between the trap level and the valence band.

Guseinov, A. G.; Salmanov, V. M.; Mamedov, R. M. [Baku State University (Azerbaijan)], E-mail: rovshan63@rambler.ru

2006-04-15T23:59:59.000Z

212

Electroluminescence and phototrigger effect in single crystals of GaS{sub x}Se{sub 1-x} alloys  

SciTech Connect (OSTI)

The effects of switching and electroluminescence as well as the interrelation between these effects in single crystals of GaS{sub x}Se{sub 1-x} alloys are detected and studied. It is established that the threshold voltage for switching depends on temperature, resistivity, and composition of alloys, and also on the intensity and spectrum of photoactive light. As a result, a phototrigger effect is observed; this effect arises under irradiation with light from the fundamental-absorption region. Electroluminescence is observed in the subthreshold region of the current-voltage characteristic; the electroluminescence intensity decreases drastically to zero as the sample is switched from a high-resistivity state to a low-resistivity state. Experimental data indicating that the electroluminescence and the switching effect are based on the injection mechanism (as it takes place in other layered crystals of the III-V type) are reported.

Kyazym-Zade, A. G., E-mail: bsu_aydin@yahoo.com; Salmanov, V. M.; Mokhtari, A. G.; Dadashova, V. V.; Agaeva, A. A. [Baku State University (Azerbaijan)

2008-05-15T23:59:59.000Z

213

The synthesis, single-crystal structure, optical absorption, and resistivity of Th{sub 2}GeSe{sub 5}  

SciTech Connect (OSTI)

The compound Th{sub 2}GeSe{sub 5} has been synthesized by the reaction of the elements at 1273 K. From a single-crystal study Th{sub 2}GeSe{sub 5} crystallizes in the Ba{sub 5}Si{sub 3} structure type with four formula units in the space group D{sup 8}{sub 4h}?P4/ncc of the tetragonal system in a cell with dimensions a=7.4968(4) Å and c=13.6302(9) Å at 100(2) K. From optical absorption measurements Th{sub 2}GeSe{sub 5} is found to have an optical band gap of 1.92 eV (indirect) or 1.98 eV (direct), consistent with its red color. Th{sub 2}GeSe{sub 5} is a wide gap semiconductor, as indicated by its electrical resistivity at 298 K of 4.37(2)×10{sup 9} ? cm measured on a single crystal. - Graphical abstract: The structure of Th{sub 2}GeSe{sub 5}. Display Omitted - Highlights: • The new compound Th{sub 2}GeSe{sub 5} was synthesized from the elements and recrystallized from Sb{sub 2}Se{sub 3}. • Th{sub 2}GeSe{sub 5} crystallizes in the Ba{sub 5}Si{sub 3} structure type. • The band gap of Th{sub 2}GeSe{sub 5} is1.92 eV and its resistivity shows it to be a wide gap semiconductor.

Koscielski, Lukasz A.; Malliakas, Christos D.; Sarjeant, Amy A.; Ibers, James A., E-mail: ibers@chem.northwestern.edu

2013-09-15T23:59:59.000Z

214

Surface structure determinations of crystalline ionic thin films grown on transition metal single crystal surfaces by low energy electron diffraction  

SciTech Connect (OSTI)

The surface structures of NaCl(100), LiF(100) and alpha-MgCl2(0001) adsorbed on various metal single crystals have been determined by low energy electron diffraction (LEED). Thin films of these salts were grown on metal substrates by exposing the heated metal surface to a molecular flux of salt emitted from a Knudsen cell. This method of investigating thin films of insulators (ionic salts) on a conducting substrate (metal) circumvents surface charging problems that plagued bulk studies, thereby allowing the use of electron-based techniques to characterize the surface.

Roberts, J.G.

2000-05-01T23:59:59.000Z

215

A statistical model approximation for perovskite solid-solutions: a Raman study of lead-zirconate- titanate single crystal  

SciTech Connect (OSTI)

Lead titanate (PbTiO3) is a classical example of a ferroelectric perovskite oxide illustrating a displacive phase transition accompanied by a softening of a symmetry-breaking mode. The underlying assumption justifying the soft-mode theory is that the crystal is macroscopically sufficiently uniform so that a meaningful free energy function can be formed. In contrast to PbTiO3, experimental studies show that the phase transition behaviour of lead-zirconate-titanate solid solution (PZT) is far more subtle. Most of the studies on the PZT system have been dedicated to ceramic or powder samples, in which case an unambiguous soft-mode study is not possible, as modes with different symmetries appear together. Our Raman scattering study on titanium-rich PZT single crystal shows that the phase transitions in PZT cannot be described by a simple soft-mode theory. In strong contrast to PbTiO3, splitting of transverse E-symmetry modes reveals that there are different locally-ordered regions. The role of crystal defects, random distribution of Ti and Zr at the B- cation site and Pb ions shifted away from their ideal positions, dictates the phase transition mechanism. A statistical model explaining the observed peak splitting and phase transformation to a complex state with spatially varying local order in the vicinity of the morphotropic phase boundary is given.

Frantti, Johannes [Aalto University, Finland; Fujioka, Y [Aalto University, Finland; Puretzky, Alexander A [ORNL; Xie, Y [Simon Fraser University, Canada; Glazer, A [Clarendon Laboratory, Department of Physics, University of Oxford

2013-01-01T23:59:59.000Z

216

Resistivity measurements of iodine single crystals by an A.C. technique  

E-Print Network [OSTI]

The temperature dep ndence of th. ! capac! tance of tvlo iodine sin;, le crystals. Iiessur. . cents on samp! e 8 acre rinds in the c- crystallo''rcphic diection and those on samo) e C 0 . , 'DPlatl 5 ( !Gout PP5' ) in the a-c p]ane. 20 :t. CI 0 Lu LIJ LJ I... The temperature dep ndence of th. ! capac! tance of tvlo iodine sin;, le crystals. Iiessur. . cents on samp! e 8 acre rinds in the c- crystallo''rcphic diection and those on samo) e C 0 . , 'DPlatl 5 ( !Gout PP5' ) in the a-c p]ane. 20 :t. CI 0 Lu LIJ LJ I...

Intararithi, Thanom

2012-06-07T23:59:59.000Z

217

Sulfur incorporation into copper indium diselenide single crystals through annealing in hydrogen sulfide  

SciTech Connect (OSTI)

CuInSe{sub 2} crystals were sulfurized in a H{sub 2}S-Ar gas mixture at 575 deg. C. The focus was on the resulting mass transport, in particular, on the interdiffusion of Se and S. Experiments were done for various sulfurization times, and the resulting S distribution was measured by Auger electron spectroscopy sputter depth profiling and analyzed with the Boltzmann-Matano method. A one-dimensional diffusion process had shaped the S distribution in these crystals. The respective diffusion coefficient was on the order of 10{sup -16} cm{sup 2}/s, and it varied only slightly with the S content in CuIn(Se,S){sub 2}.

Titus, Jochen; Birkmire, Robert W.; Hack, Christina; Mueller, Georg; McKeown, Patrick [Institute of Energy Conversion, University of Delaware, Newark, Delaware 19716 (United States); Crystal Growth Laboratory, Department of Materials Science, University of Erlangen-Nuernberg (Germany); Evans East, Princeton, New Jersey 08520 (United States)

2006-02-15T23:59:59.000Z

218

E-Print Network 3.0 - adp single crystals Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

force Yoko Hirono-Hara* Summary: the rotation and catalytic event. ADP inhibition ATP synthase F1-ATPase magnetic tweezers single... , and the two are bound with ATP and...

219

Injection photodiodes based on low-resistivity ZnS single crystals  

SciTech Connect (OSTI)

Results of an experimental study of Ni-n-n{sup +}-In photodiode structures fabricated from a low-resistivity ZnS:Al crystal (n{sup +}-region) are reported. The high-resistivity compensated n-type layer is produced by thermal diffusion of silver. The photodiodes exhibit an injection amplification of the photocurrent under a forward bias of 1-10 V. The dependence of the currents through the diodes on the thickness of the n-type layer in the dark and under UV irradiation is determined. The photosensitivity is at a maximum in the fundamental absorption range in a narrow spectral band.

Losev, V. V., E-mail: morozova-tamara@mail.ru [Moscow State Institute (Technical University) of Electronic Engineering (Russian Federation)

2009-12-15T23:59:59.000Z

220

1Surface structure of cleaved (001) USB2 single crystal surface  

SciTech Connect (OSTI)

We have achieved what we believe to be the first atomic resolution STM images for a uranium compound USb2 taken at room temperature. The a, b, and c lattice parameters in the images confirm that the tetragonal USb2crystals cleave on the (00 I) basal plane as expected. Our calculations indicate a symmetric cut between Sb planes to be the most favorable cleavage plane and U atoms to be responsible for most ofthe density of states measured by STM. Since the spacing between Sb atoms and between U atoms is the same, STM topography only cannot unambiguously identify the surface atom species.

Chen, Shao-ping [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Magnetic properties of (FeIn{sub 2}S{sub 4}){sub 1-x}(In{sub 2}S{sub 3}){sub x} alloy single crystals  

SciTech Connect (OSTI)

(FeIn{sub 2}S{sub 4}){sub 1-x}(In{sub 2}S{sub 3}){sub x} alloy single crystals are grown by oriented crystallization in the entire range of component concentrations. For the single crystals, studies of the magnetic properties are carried out in the temperature range 4-300 K and the magnetic-field range 0-14 T. It is established that almost all of the alloys are paramagnetic materials at temperatures down to the lowest achievable temperatures ({approx}4 K). It is shown that the ground magnetic phase state of the alloys is the spin-glass state with the freezing temperature steadily increasing with increasing Fe{sup 2+} cation content. The most probable causes and mechanism of formation of the magnetic state of the (FeIn{sub 2}S{sub 4}){sub 1-x}(In{sub 2}S{sub 3}){sub x} crystals are discussed.

Bodnar, I. V., E-mail: chemzav@bsuir.by; Novikova, M. A. [Belarussian State University of Information and Radio Electronics (Belarus); Trukhanov, S. V. [National Academy of Sciences, Scientific and Practical Center for Material Science (Belarus)

2013-05-15T23:59:59.000Z

222

Investigating the origin of the high photoconductivity of rubrene single crystals  

Science Journals Connector (OSTI)

The rubrene molecular crystal has the unique property of showing a strong photoconductivity for light wavelengths that are close to the absorption edge. We studied the microsecond dynamics of the photoconductivity induced by short light pulses to characterize the way in which photoinduced excitons efficiently ionize to produce free charge carriers. We found that the photoconductivity is produced by carriers released after an average time of 100?s from a “reservoir state” that originates from the photoexcited molecular excitons. The conversion of photoexcited excitons into this reservoir state happens only at the surface of the crystal within a depth of the order of a few micrometers, but in this region close to the surface, a photoexcited molecular exciton has a probability of the order of unity to ultimately lead to a mobile charge carrier. This high carrier photoexcitation efficiency leads to a pronounced shortening of the photocurrent rise time for decreasing wavelength or increasing energy of the excitation pulses because of the effect of quadratic recombination of the photocarriers.

Hikmat Najafov; Byunggook Lyu; Ivan Biaggio; Vitaly Podzorov

2008-03-06T23:59:59.000Z

223

Effect of an Electric Field on the Growth and Optoelectronic Properties of Quasi-One-Dimensional Organic Single Crystals of 1-(Phenylazo)-2-naphthol  

Science Journals Connector (OSTI)

Effect of an Electric Field on the Growth and Optoelectronic Properties of Quasi-One-Dimensional Organic Single Crystals of 1-(Phenylazo)-2-naphthol ... The elementary component of the crystal needle is believed to be the individual molecular column as indicted by the X-ray diffraction results. ... Because ?? was measured between two Pt electrodes and ?? between two ITO electrodes, the contact resistance may play a role. ...

Chong-yang Liu; Vincent Lynch; Allen J. Bard

1997-04-16T23:59:59.000Z

224

Evaluation of the dosimetric properties of a synthetic single crystal diamond detector in high energy clinical proton beams  

SciTech Connect (OSTI)

Purpose: To investigate the dosimetric properties of a synthetic single crystal diamond Schottky diode for accurate relative dose measurements in large and small field high-energy clinical proton beams.Methods: The dosimetric properties of a synthetic single crystal diamond detector were assessed by comparison with a reference Markus parallel plate ionization chamber, an Exradin A16 microionization chamber, and Exradin T1a ion chamber. The diamond detector was operated at zero bias voltage at all times. Comparative dose distribution measurements were performed by means of Fractional depth dose curves and lateral beam profiles in clinical proton beams of energies 155 and 250 MeV for a 14 cm square cerrobend aperture and 126 MeV for 3, 2, and 1 cm diameter circular brass collimators. ICRU Report No. 78 recommended beam parameters were used to compare fractional depth dose curves and beam profiles obtained using the diamond detector and the reference ionization chamber. Warm-up/stability of the detector response and linearity with dose were evaluated in a 250 MeV proton beam and dose rate dependence was evaluated in a 126 MeV proton beam. Stem effect and the azimuthal angle dependence of the diode response were also evaluated.Results: A maximum deviation in diamond detector signal from the average reading of less than 0.5% was found during the warm-up irradiation procedure. The detector response showed a good linear behavior as a function of dose with observed deviations below 0.5% over a dose range from 50 to 500 cGy. The detector response was dose rate independent, with deviations below 0.5% in the investigated dose rates ranging from 85 to 300 cGy/min. Stem effect and azimuthal angle dependence of the diode signal were within 0.5%. Fractional depth dose curves and lateral beam profiles obtained with the diamond detector were in good agreement with those measured using reference dosimeters.Conclusions: The observed dosimetric properties of the synthetic single crystal diamond detector indicate that its behavior is proton energy independent and dose rate independent in the investigated energy and dose rate range and it is suitable for accurate relative dosimetric measurements in large as well as in small field high energy clinical proton beams.

Mandapaka, A. K.; Ghebremedhin, A.; Patyal, B. [Department of Radiation Medicine, Loma Linda University Medical Center, 11234 Anderson Street, Loma Linda, California 92354 (United States)] [Department of Radiation Medicine, Loma Linda University Medical Center, 11234 Anderson Street, Loma Linda, California 92354 (United States); Marinelli, Marco; Prestopino, G.; Verona, C.; Verona-Rinati, G. [INFN–Dipartimento di Ingegneria Industriale, Università di Roma ‘Tor Vergata’, Via del Politecnico 1, 00133 Roma (Italy)] [INFN–Dipartimento di Ingegneria Industriale, Università di Roma ‘Tor Vergata’, Via del Politecnico 1, 00133 Roma (Italy)

2013-12-15T23:59:59.000Z

225

Effect of Mg doping on the growth aspects, crystalline perfection, and optical and thermal properties of congruent LiNbO3 single crystals  

Science Journals Connector (OSTI)

Single crystals of Mg-doped lithium niobate with diffrent dopant concentrations were grown using a automatic diameter controlled crystal puller. Crack formation at the higher dopant concentration (6 mol%) was observed, although a good-quality crystal could be grown at the same concentration with a change in the pulling rate; this result is related to the thermal conductivity of the material. An investigation of the crystalline perfection and optical properties and a thermal analysis were carried out, in consideration of potential usage for device fabrication.

Riscob, B.

2013-10-26T23:59:59.000Z

226

Microsoft Word - 41344_Texas A&M_Mech of Single Crystal Blades_Factsheet_Rev01_10-03.doc  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Investigation into the Mechanics of Single Crystal Turbine Blades Investigation into the Mechanics of Single Crystal Turbine Blades with a View Toward Enhancing Turbine Efficiency October 8, 2003 DE-FC26-01NT41344 1 FACT SHEET I. PROJECT PARTICIPANTS PI: K.R.Rajagopal, Texas A & M University Co-PI: I.J.Rao, New Jersey Institute of Technology II. PROJECT DESCRIPTION A. Objective(s) To model the behavior of single crystal turbine blades within a full thermodynamic framework, accounting for the evolving anisotropy of the material as it deforms and the creep behavior at different temperatures. B. Background/Relevancy The preferred solution to the generation of electric power is by means of gas turbines as they are cheaper and produce considerably less carbon monoxide than conventional methods of power

227

Photo-Seebeck effect in tetragonal PbO single crystals  

SciTech Connect (OSTI)

We report the observation of photo-Seebeck effect in tetragonal PbO crystals. The photo-induced carriers contribute to the transport phenomena, and consequently the electrical conductivity increases and the Seebeck coefficient decreases with increasing photon flux density. A parallel-circuit model is used to evaluate the actual contributions of photo-excited carriers from the measured transport data. The photo-induced carrier concentration estimated from the Seebeck coefficient increases almost linearly with increasing photon flux density, indicating a successful photo-doping effect on the thermoelectric property. The mobility decreases by illumination but the reduction rate strongly depends on the illuminated photon energy. Possible mechanisms of such photon-energy-dependent mobility are discussed.

Mondal, P. S.; Okazaki, R.; Taniguchi, H.; Terasaki, I. [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)

2013-11-07T23:59:59.000Z

228

Itinerant and local-moment magnetism in EuCr2As2 single crystals  

Science Journals Connector (OSTI)

We report on the crystal structure, physical properties, and electronic structure calculations for the ternary pnictide compound EuCr2As2. X-ray diffraction studies confirmed that EuCr2As2 crystalizes in the ThCr2Si2-type tetragonal structure (space group I4/mmm). The Eu ions are in a stable divalent state in this compound. Eu moments in EuCr2As2 order magnetically below Tm = 21 K. A sharp increase in the magnetic susceptibility below Tm and the positive value of the paramagnetic Curie temperature obtained from the Curie-Weiss fit suggest dominant ferromagnetic interactions. The heat capacity exhibits a sharp ?-shape anomaly at Tm, confirming the bulk nature of the magnetic transition. The extracted magnetic entropy at the magnetic transition temperature is consistent with the theoretical value Rln(2S+1) for S=7/2 of the Eu2+ ion. The temperature dependence of the electrical resistivity ?(T) shows metallic behavior along with an anomaly at 21 K. In addition, we observe a reasonably large negative magnetoresistance (??24%) at lower temperature. Electronic structure calculations for EuCr2As2 reveal a moderately high density of states of Cr-3d orbitals at the Fermi energy, indicating that the nonmagnetic state of Cr is unstable against magnetic order. Our density functional calculations for EuCr2As2 predict a G-type AFM order in the Cr sublattice. The electronic structure calculations suggest a weak interlayer coupling of the Eu moments.

U. B. Paramanik; R. Prasad; C. Geibel; Z. Hossain

2014-04-25T23:59:59.000Z

229

Increasing the laser-induced damage threshold of single-crystal ZnGeP{sub 2}  

SciTech Connect (OSTI)

The laser-induced damage threshold (LIDT) of single-crystal zinc germanium phosphide (ZGP), ZnGeP{sub 2}, was increased to 2 J/cm{sup 2} at 2.05 {mu}m and a 10 kHz pulse rate frequency (double the previously measured value of 1 J/cm{sup 2}). This increased LIDT was achieved by improving the polishing of ZGP optical parametric oscillator crystals. Two different polishing techniques were evaluated. Surfaces were characterized using scanning white-light interferometry to determine rms surface roughness and sample flatness. The photon backscatter technique was used to determine the degree of surface and subsurface damage in the sample induced through the fabrication process. The effect of subsurface damage in the samples was studied by removing different amounts of material during polishing for otherwise identical samples. Statistical LIDT was measured using a high-average-power, repetitively Q-switched Tm,Ho:YLF 2.05 {mu}m pump laser. On average, lower surface roughness and photon backscatter measurements were a good indicator of ZGP samples exhibiting higher LIDT. The removal of more material during polishing significantly improved the LIDT of otherwise identical samples, indicating the importance of subsurface damage defects in the LIDT of ZGP.

Zawilski, Kevin T.; Setzler, Scott D.; Schunemann, Peter G.; Pollak, Thomas M. [BAE Systems, Advanced Systems and Technology, P.O. Box 868, MER15-1813, Nashua, New Hampshire 03061-0868 (United States)

2006-11-15T23:59:59.000Z

230

Designing the Mode solving of the photonic crystal fiber via BPM and Exploring the Single-Mode Properties  

E-Print Network [OSTI]

Microstructured optical fibers (MOFs) are one of the most exciting recent developments in fiber optics. A MOF usually consists of a hexagonal arrangement of air holes running down the length of a silica fiber surrounding a central core of solid silica or, in some cases air. MOFs can exhibit a number of unique properties, including zero dispersion at visible wavelengths and low or high effective nonlinearity [3]-[17], By varying the size of the holes and their number and position, one can also design MOFs with carefully controlled dispersive and modal properties. In this paper, we analyze and modeling the behavior of the photonic crystal fiber (PCF) by using in the first step a propagator method based on the BPM method. With our BPM software, the electric field contour of the fundamental mode of PCF was demonstrated. We also used it to see the variation of the effective index; an effective index model confirms that such a fiber can be single mode for any wavelength. It would make a study of photonic crystal fi...

Debbal, Mohammed

2012-01-01T23:59:59.000Z

231

Heavy-electron behavior in single-crystal YbNi{sub 2}B{sub 2}C  

SciTech Connect (OSTI)

We have measured the magnetic susceptibility, specific heat, and electrical resistivity on single crystals of the intermetallic borocarbide YbNi{sub 2}B{sub 2}C. An enhanced linear contribution is observed in the specific heat with a Sommerfeld coefficient of 530 mJ/molK{sup 2}, indicative of a heavy-electron system with a Kondo temperature {approximately}10 K. The magnetic susceptibility, which is anisotropic and Curie-Weiss-like at high temperatures, is also consistent with our interpretation of a strongly correlated ground state at low temperatures and crystal-electric- field excitations at higher temperatures. At {ital T}=1.8 K, the Wilson ratio is determined to be 0.85 using the high-temperature effective moment. The resistivity shows a quadratic temperature dependence below 1.5 K with a {ital T}{sup 2} coefficient of 1.2 {mu}{Omega}cmK{sup {minus}2}. Unlike the other members of the series {ital R}Ni{sub 2}B{sub 2}C ({ital R}=Y, Gd{endash}Lu), YbNi{sub 2}B{sub 2}C does not order above our lowest measurement temperature of 0.34 K. The suppression of superconductivity in YbNi{sub 2}B{sub 2}C is consistent with a significantly enhanced hybridization between the conduction electrons and the 4{ital f} states. {copyright} {ital 1996 The American Physical Society.}

Yatskar, A.; Budraa, N.K.; Beyermann, W.P. [University of California, Riverside, California 92521 (United States)] [University of California, Riverside, California 92521 (United States); Canfield, P.C.; Budko, S.L. [Ames Laboratory and Iowa State University, Ames, Iowa 50011 (United States)] [Ames Laboratory and Iowa State University, Ames, Iowa 50011 (United States)

1996-08-01T23:59:59.000Z

232

Evolution of London penetration depth with scattering in single crystals of K1?xNaxFe2As2  

Science Journals Connector (OSTI)

London penetration depth, ?(T), was measured in single crystals of K1?xNaxFe2As2, x=0 and 0.07, down to temperatures of 50 mK, ?Tc/50. Isovalent substitution of Na for K significantly increases impurity scattering, with ?(Tc) rising from 0.2 to 2.2 ?? cm, and leads to a suppression of Tc from 3.5 to 2.8 K. At the same time, a close to T-linear ??(T) in pure samples changes to almost T2 in the substituted samples. The behavior never becomes exponential as expected for the accidental nodes, as opposed to T2 dependence in superconductors with symmetry imposed line nodes. The superfluid density in the full temperature range follows a simple clean and dirty d-wave dependence, for pure and substituted samples, respectively. This result contradicts suggestions of multiband scenarios with strongly different gap structure on four sheets of the Fermi surface.

H. Kim; M. A. Tanatar; Yong Liu; Zachary Cole Sims; Chenglin Zhang; Pengcheng Dai; T. A. Lograsso; R. Prozorov

2014-05-30T23:59:59.000Z

233

Photocatalytic Activity of Bulk TiO{sub 2} Anatase and Rutile Single Crystals Using Infrared Absorption Spectroscopy  

SciTech Connect (OSTI)

A systematic study on the photocatalytic activity of well-defined, macroscopic bulk single-crystal TiO{sub 2} anatase and rutile samples has been carried out, which allows us to link photoreactions at surfaces of well-defined oxide semiconductors to an important bulk property with regard to photochemistry, the life time of e-h pairs generated in the bulk of the oxides by photon absorption. The anatase (101) surface shows a substantially higher activity, by an order of magnitude, for CO photo-oxidation to CO{sub 2} than the rutile (110) surface. This surprisingly large difference in activity tracks the bulk e-h pair lifetime difference for the two TiO{sub 2} modifications as determined by contactless transient photoconductance measurements on the corresponding bulk materials.

Xu Mingchun; Gao Youkun [Department of Physical Chemistry I, Ruhr-Universitaet Bochum, 44780 (Germany); Moreno, Elias Martinez; Kunst, Marinus [Hahn-Meitner-Institut, Glienicker Strasse 100, D-1000 Berlin 39 (Germany); Muhler, Martin [Laboratory of Industrial Chemistry, Ruhr-Universitaet Bochum, 44780 (Germany); Wang Yuemin [Department of Physical Chemistry I, Ruhr-Universitaet Bochum, 44780 (Germany); Laboratory of Industrial Chemistry, Ruhr-Universitaet Bochum, 44780 (Germany); Idriss, Hicham [Department of Chemistry, University of Aberdeen and School of Engineering, Robert Gordon University, AB24 3EU Aberdeen, Scotland (United Kingdom); Woell, Christof [Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe (Germany)

2011-04-01T23:59:59.000Z

234

Novel vortex dynamics in untwinned YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} single crystals  

SciTech Connect (OSTI)

Magnetotransport measurements on a clean, untwinned YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} single crystal show that the vortex dynamics at temperatures just below the vortex lattice melting transition are highly dependent on the type of modulation of the probing current. While in the case of DC current the flux flow is disordered, the {open_quotes}shaking{close_quotes} of the vortex lattice by a square-wave current leads to a more uniform vortex motion. A small asymmetry ({approximately}10%) in the durations of the positive and negative parts of the square-wave period induces periodical oscillations of the voltage response amplitude. The period of oscillations ({approximately}100 s) is the same order of magnitude as the time needed for vortices to cross the sample (transit time). The authors relate the observed voltage oscillations to a periodically ordered vortex motion.

Gordeev, S.N.; Oussena, M.; Pinfold, S.; Langan, R.M. [Univ. of Southampton (United Kingdom)] [and others

1996-12-01T23:59:59.000Z

235

Origins of low resistivity and Ge donor level in Ge ion-implanted ZnO bulk single crystals  

SciTech Connect (OSTI)

The energy level of Ge in Ge-ion implanted ZnO single crystals is studied by Hall-effect and photoluminescence (PL) methods. The variations in resistivity from ?10{sup 3} ?cm for un-implanted samples to ?10{sup ?2} ?cm for as-implanted ones are observed. The resistivity is further decreased to ?10{sup ?3} ?cm by annealing. The origins of the low resistivity are attributed to both the zinc interstitial (Zn{sub i}) related defects and the electrical activated Ge donor. An activation energy of Ge donors estimated from the temperature dependence of carrier concentration is 102 meV. In PL studies, the new peak at 372 nm (3.33 eV) related to the Ge donor is observed in 1000 °C annealed samples.

Kamioka, K.; Oga, T.; Izawa, Y.; Kuriyama, K. [College of Engineering and Research Center of Ion Beam Technology, Hosei University Koganei, Tokyo 184-8584 (Japan); Kushida, K. [Departments of Arts and Sciences, Osaka Kyoiku University Kashiwara, Osaka 582-8582 (Japan)

2013-12-04T23:59:59.000Z

236

Detection of charge transfer processes in Cr-doped SrTiO{sub 3} single crystals  

SciTech Connect (OSTI)

An insulator-to-metal transition is observed in Cr-doped SrTiO{sub 3} single crystals upon extended exposure to a high electric field, namely, electroconditioning (EC). Electron paramagnetic resonance (EPR) and transport measurements under laser irradiation show anticorrelation between the Cr{sup 3+} EPR signal and the electrical current. This proves that the Cr{sup 3+} ions are responsible for the photocurrent that initiates the EC process. We observe the presence of Cr{sup 3+}/Cr{sup 4+} mixed valencies in the bulk in the conducting state. The EPR characterization of the spectra in the conducting state excludes the possibility of a Cr{sup 3+}-oxygen vacancy complex in the bulk as a result of the EC.

La Mattina, F. [Physik-Institut der Universitaet Zuerich, Winterthurerstr. 190, CH-8057 Zuerich (Switzerland); IBM Research, Zurich Research Laboratory, Saeumerstr. 4, CH-8803 Rueschlikon (Switzerland); Bednorz, J. G.; Alvarado, S. F. [IBM Research, Zurich Research Laboratory, Saeumerstr. 4, CH-8803 Rueschlikon (Switzerland); Shengelaya, A. [Physics Institute of Tbilisi State University, Chavchavadze 3, GE-0128, Tbilisi (Georgia); Keller, H. [Physik-Institut der Universitaet Zuerich, Winterthurerstr. 190, CH-8057 Zuerich (Switzerland)

2008-07-14T23:59:59.000Z

237

Temperature-dependent photocarrier recombination dynamics in Cu{sub 2}ZnSnS{sub 4} single crystals  

SciTech Connect (OSTI)

Time-resolved photoluminescence (PL) measurements have been used to study the temperature-dependent photocarrier recombination dynamics in Cu{sub 2}ZnSnS{sub 4} (CZTS) single crystals. We found a significant change of nearly four orders of magnitude of the PL decay time, from microseconds at low temperatures to subnanoseconds at room temperature. The slow PL decay at low temperatures indicates localization of the photocarriers at the band tails. Due to the large band tail states, the PL decay time depends strongly on both the photon energy and excitation density. It is pointed out that the drastically enhanced nonradiative recombination at high temperatures is one of the main factors that determine the power conversion efficiency of CZTS-based solar cells.

Phuong, Le Quang; Kanemitsu, Yoshihiko, E-mail: kanemitu@scl.kyoto-u.ac.jp [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Japan Science and Technology Agency, CREST, Uji, Kyoto 611-0011 (Japan); Okano, Makoto; Yamada, Yasuhiro [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Nagaoka, Akira; Yoshino, Kenji [Department of Applied Physics and Electronic Engineering, University of Miyazaki, Miyazaki 889-2192 (Japan)

2014-02-24T23:59:59.000Z

238

A Successful Synthesis of the CoCrFeNiAl{sub 0.3} Single-Crystal, High-Entropy Alloy by Bridgman Solidification  

SciTech Connect (OSTI)

For the first time, a face-centered-cubic, single-crystal CoCrFeNiAl{sub 0.3} (designated as Al0.3), high-entropy alloy (HEA) was successfully synthesized by the Bridgman solidification (BS) method, at an extremely low withdrawal velocity through a constant temperature gradient, for which it underwent two BS steps. Specially, at the first BS step, the alloy sample underwent several morphological transitions accompanying the crystal growth from the melt. This microstructure evolves from as-cast dendrites, to equiaxed grains, and then to columnar crystals, and last to the single crystal. In particular, at the equiaxed-grain region, some visible annealing twins were observed, which indicates a low stacking fault energy of the Al0.3 alloy. Although a body-centered- cubic CoCrFeNiAl (Al1) HEA was also prepared under the same conditions, only a single columnar-crystal structure with instinctively preferential crystallographic orientations was obtained by the same procedure. A similar morphological transition from dendrites to equiaxed grains occurred at the equiaxed-grain region in Al1 alloy, but the annealing twins were not observed probably because a higher Al addition leads to a higher stacking fault energy for this alloy.

Ma, S. G.; Zhang, S. F.; Gao, M. C.; Liaw, P. K.; Zhang, Y.

2013-12-01T23:59:59.000Z

239

Subeutectic Growth of Single-Crystal Silicon Nanowires Grown on and Wrapped with Graphene Nanosheets: High-Performance Anode Material for Lithium-Ion Battery  

Science Journals Connector (OSTI)

Subeutectic Growth of Single-Crystal Silicon Nanowires Grown on and Wrapped with Graphene Nanosheets: High-Performance Anode Material for Lithium-Ion Battery ... Yu, A.; Park, H. W.; Davies, A.; Higgins, D.; Chen, Z.; Xaio, X.Free-Standing Layer-by-Layer Hybrid Thin Film of Graphene-MnO2 Nanotube as Anode for Lithium Ion Batteries J. Phys. ...

Fathy M Hassan; Abdel Rahman Elsayed; Victor Chabot; Rasim Batmaz; Xingcheng Xiao; Zhongwei Chen

2014-07-31T23:59:59.000Z

240

A phenomenological thermodynamic potential for BaTiO3 single crystals Department of Materials Science and Engineering, The Pennsylvania State University, University Park,  

E-Print Network [OSTI]

A phenomenological thermodynamic potential for BaTiO3 single crystals Y. L. Lia Department; accepted 4 August 2005; published online 16 September 2005 A phenomenological thermodynamic potential is to con- struct such a thermodynamic potential. II. PHENOMENOLOGICAL THERMODYNAMIC POTENTIAL

Chen, Long-Qing

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


241

Anisotropic magnetoresistance of single-crystal HoNi2B2C and the interplay of magnetic and superconducting order  

E-Print Network [OSTI]

The in-plane resistivity and magnetization measurements as a function of the magnitude and direction of the magnetic field and the temperature are reported for single-crystal samples of the HoNi2B2C magnetic superconductor. Features corresponding...

Rathnayaka, KDD; Naugle, Donald G.; Cho, BK; Canfield, PC.

1996-01-01T23:59:59.000Z

242

Surface Atomic Structure of As-prepared Nd1Ba2Cu3Oy Single Crystals Characterized Using An UHV-STM System  

Science Journals Connector (OSTI)

An ultrahigh vacuum scanning tunneling microscope/spectroscopy (UHV-STM/STS) system has been used to...1Ba2Cu3Oy (Nd123) single crystals. A quasi-square lattice with average lattice spacings of 4×4 Å2 has been ob...

Wu Ting; T. Egi; R. Itti; K. Kuroda; N. Koshizuka

1996-01-01T23:59:59.000Z

243

The Role of -Al2O3 Single Crystal Support to Pt Nanoparticles Construction Zhongfan Zhang*, Long Li*, Lin-lin Wang**, Sergio I. Sanchez***, Qi Wang****,  

E-Print Network [OSTI]

The Role of -Al2O3 Single Crystal Support to Pt Nanoparticles Construction Zhongfan Zhang*, Long Li the preparation of a model Pt/-Al2O3 catalyst and its characterization by a cross-sectional high-resolution electron microscopy (XHREM) method. Pt/-Al2O3 is the most important technologically-relevant heterogeneous

Frenkel, Anatoly

244

Tightly integrated single- and multi-crystal data collection strategy calculation and parallelized data processing in JBluIce beamline control system  

Science Journals Connector (OSTI)

Single- and multi-crystal data collection strategy and automated data processing have been tightly integrated into the JBluIce graphical user interface. Grid Engine is used to distribute these processes into multiple workstations to make efficient use of all available computing resources.

Pothineni, S.B.

2014-11-18T23:59:59.000Z

245

Rapid Charge Transport in Dye-Sensitized Solar Cells Made from Vertically Aligned Single-Crystal Rutile TiO2 Nanowires  

SciTech Connect (OSTI)

A rapid solvothermal approach was used to synthesize aligned 1D single-crystal rutile TiO2 nanowire (NW) arrays on transparent conducting substrates as electrodes for dye-sensitized solar cells. The NW arrays showed a more than 200 times faster charge transport (see picture) and a factor four lower defect state density than conventional rutile nanoparticle films.

Feng, X.; Zhu, K.; Frank, A. J.; Grimes, C. A.; Mallouk, T. E.

2012-03-12T23:59:59.000Z

246

X-Ray Storage Luminescence of BaFCl:Eu2+ Single Crystals Nomadics, Inc., 1024 South InnoVation Way, Stillwater, Oklahoma 74074  

E-Print Network [OSTI]

X-Ray Storage Luminescence of BaFCl:Eu2+ Single Crystals Wei Chen* Nomadics, Inc., 1024 South InnoVed: January 18, 2005; In Final Form: March 22, 2005 Temperature behaviors of X-ray luminescence (XL might not be oxidized to Eu3+ upon X-ray or -irradiation. Instead, the color centers, Cl excitons

Chen, Reuven

247

Evaluation of Melt-Grown, ZnO Single Crystals for Use as Alpha-Particle Detectors  

SciTech Connect (OSTI)

As part of an ongoing investigation of the scintillation properties of zinc-oxide-based scintillators, several melt-grown, ZnO single crystals have been characterized using -particle excitation, infrared reflectance, and room temperature photoluminescence. The crystals, grown by Cermet, Inc. using a pressurized melt growth process, were doped with Group 1 elements (Li), Group 2 elements (Mg), Group 3 elements (Ga, In) and Lanthanides (Gd, Er, Tm). The goals of these studies are to better understand the scintillation mechanisms associated with various members of the ZnO scintillator family and to then use this knowledge to improve the radiation detection capabilities of ZnO-based scintillators. One application for which ZnO is particularly well suited as a scintillator is as the associated particle detector in a deuterium-tritium (D-T) neutron generator. Application requirements include the exclusion of organic materials, outstanding timing resolution, and high radiation resistance. ZnO(Ga) and ZnO(In) have demonstrated fast (sub-nanosecond) decay times with relatively low light yields, and ZnO(Ga) has been used in a powder form as the associated particle detector for a D-T neutron generator. Four promising candidate materials, ZnO, ZnO:Ga, ZnO:In,Li, and ZnO:Er,Li, were identified in this study. These four samples demonstrated sub-nanosecond decay times and alpha particle excited luminescence comparable to BC-400 fast plastic scintillator. The ZnO:Mg,Ga, ZnO:Gd, and ZnO:Li samples demonstrated appreciable slow (microsecond) decay components that would be incompatible with high-counting-rate applications.

Neal, John S [ORNL; Giles, N. C. [West Virginia University; Yang, Xiaocheng [West Virginia University; Wall, R. Andrew [Wake Forest University, Winston-Salem, NC; Ucer, Burak [Wake Forest University, Winston-Salem, NC; Williams, Richard T. [Wake Forest University, Winston-Salem, NC; Wisniewski, Dariusz J [ORNL; Boatner, Lynn A [ORNL; Rengarajan, Varatharajan [ORNL; Nause, Jeff E [ORNL; Nemeth, Bell [Cermet, Inc., Atlanta

2008-01-01T23:59:59.000Z

248

New oxyfluoride glass with high fluorine content and laser patterning of nonlinear optical BaAlBO{sub 3}F{sub 2} single crystal line  

SciTech Connect (OSTI)

A new oxyfluoride glass of 50BaF{sub 2}-25Al{sub 2}O{sub 3}-25B{sub 2}O{sub 3} (mol. %) with a large fraction of fluorine, i.e., F/(F + O) = 0.4, was prepared using a conventional melt-quenching method in order to synthesize new glass-ceramics containing nonlinear optical oxyfluoride crystals. The refractive index at 632.8 nm and ultra-violet cutoff wavelength of the glass were 1.564 and {approx}200 nm, respectively. Eu{sup 3+} ions in the glass showed a high quantum yield of 88% in the photoluminescence spectrum in the visible region. BaAlBO{sub 3}F{sub 2} crystals (size: 50-100 nm) showing second harmonic generations were formed through the crystallization of the glass. Lines consisting of BaAlBO{sub 3}F{sub 2} crystals were patterned successfully on the glass surface by laser irradiations (Yb:YVO{sub 4} laser with a wavelength of 1080 nm, laser power of 1.1 W, scanning speed of 8 {mu}m/s). High resolution transmission electron microscope observations combined with a focused ion beam technique indicate that BaAlBO{sub 3}F{sub 2} crystals are highly oriented just like a single crystal. The present study proposes that the new oxyfluoride glass and glass-ceramics prepared have a high potential for optical device applications.

Shionozaki, K.; Honma, T.; Komatsu, T. [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan)

2012-11-01T23:59:59.000Z

249

Angle-resolved photoemission study of the (100) surface of a ZrN0.93 single crystal  

Science Journals Connector (OSTI)

The (100) surface of a ZrN0.93 single crystal has been studied using angle-resolved photoemission and synchrotron radiation. A mapping of the bulk-band structure is presented and compared with an augmented-plane-wave band structure, calculated for stoichiometric composition. The experimentally determined bands are found to be located deeper below the Fermi energy than the calculated bands but the dispersions agree fairly well. A surface state is observed at 3.8 eV binding energy, for photon energies below 24 eV, and a structure interpreted as arising from vacancy induced states is observed at a binding energy of 2.1 eV for photon energies above 30 eV. The latter structure is found to exhibit a strong intensity modulation with photon energy. This intensity modulation is compared with the resonance enhancement observed in the emission from states just below the Fermi energy above the Zr 4p absorption threshold.

J. Lindström; L. I. Johansson; A. Callens; D. S. L. Law; A. N. Christensen

1987-05-15T23:59:59.000Z

250

Thermal chemistry of copper(I)-N,N '-di-sec-butylacetamidinate on Cu(110) single-crystal surfaces  

SciTech Connect (OSTI)

The surface chemistry of copper(I)-N,N'-di-sec-butylacetamidinate on Cu(110) single-crystal surfaces has been characterized under ultrahigh vacuum by temperature programmed desorption (TPD) and X-ray photoelectron spectroscopy. A series of thermal stepwise conversions were identified, starting with the partial dissociative adsorption of the copper acetamidinate dimers into a mixture of monomers and dimers on the surface. An early dissociation of a C-N bond leads to the production of N-sec-butylacetamidine, which is detected in TPD experiments in three temperature regimes, the last one centered around 480 K. Butene, and a small amount of butane, is also detected above approximately 500 K, and hydrogen production, an indication of dehydrogenation of surface fragments, is observed at 460, 550 and 670 K. In total, only about 10% of the initial copper(I)-N,N'-di-sec-butylacetamidinate adsorbed monolayer decomposes, and only about {approx}3% of carbon is left behind on the surface after heating to high temperatures. The implications of this surface chemistry to the design of chemical film growth processes using copper acetamidinates as precursors are discussed.

Ma Qiang; Zaera, Francisco; Gordon, Roy G. [Department of Chemistry, University of California, Riverside, California 92521 (United States); Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States)

2012-01-15T23:59:59.000Z

251

General matrix ENDOR line shape model applied to the methyl radical in lithium acetate dihydrate using single crystal data  

Science Journals Connector (OSTI)

A new general matrix ENDOR line shape model is tested against ENDOR data on the methyl radical in ??irradiated lithium acetate dihydrate. All parameters in the line shape model are determined or narrowly limited by experiment. These include the dipolar tensors of all protons within 5 Å of the methyl radical the microwave and radiofrequency magnetic fields and the electronic and nuclear spin–lattice and spin–spin relaxation times. The theoretical simulations agree satisfactorily with the experimental lineshape microwavemagnetic field dependence radiofrequency magnetic field dependence and angular variation of single crystalENDOR line intensities. The effective nuclear spin–lattice relaxation time is ?10 ms at 77 K and seems to be dominated by an angularly independent nuclear relaxation mechanism. The angularly dependent electron–nuclear dipolar interaction is found to be of much less importance for the ENDOR response. It is noted that the angular variation of ENDOR intensities is an important parameter to assess the nuclear relaxation mechanisms that control the ENDOR response. Data on cw and pulsed matrix ENDOR are compared and found to be similar. It is also shown that a model based on idealized line shape theory for disordered systems can satisfactorily reproduce matrix ENDOR line shapes. Both models allow calculation of the relative contributions from angularly independent and dependent ENDOR responses.

Larry Kevan; P. A. Narayana; K. Toriyama; M. Iwasaki

1979-01-01T23:59:59.000Z

252

Role of polaron hopping in leakage current behavior of a SrTiO{sub 3} single crystal  

SciTech Connect (OSTI)

We studied the ionic/electronic transport and resistance degradation behavior of dielectric oxides by solving the electrochemical transport equations. Here, we took into account the non-periodical boundary conditions for the transport equations using the Chebyshev collocation algorithm. A sandwiched Ni|SrTiO{sub 3}|Ni capacitor is considered as an example under the condition of 1.0?V, 1.0??m thickness for SrTiO{sub 3} layer, and a temperature of 150?°C. The applied voltage resulted in the migration of ionic defects (oxygen vacancies) from anode towards cathode. The simulated electric potential profile at steady state is in good agreement with the recent experimental observation. We introduced the possibility of polaron-hopping between Ti{sup 3+} and Ti{sup 4+} at the electrode interface. It is shown that both the oxygen vacancy transport and the polaron-hopping contribute to the resistance degradation of single crystal SrTiO{sub 3}, which is consistent with the experimental observations.

Cao, Y., E-mail: yxc238@psu.edu; Randall, C. A.; Chen, L. Q. [Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802 (United States); Bhattacharya, S. [Department of Materials Science and Engineering, Indian Institute of Technology Hyderabad, YM 502205 (India); Shen, J. [Department of Mathematics, Purdue University, West Lafayette, Indiana 47907 (United States)

2013-12-14T23:59:59.000Z

253

Dissolution-induced surface modifications and permeability changes associated with fluid flow through an abraded saw-cut in single crystal quartz  

E-Print Network [OSTI]

-CUT IN SINGLE CRYSTAL QUARTZ A Thesis by JAMES ALBERT BOWMAN, JR. Approved as to style and content by: Brann Jo on (Co-Chairman ommittee) Thomas T. Tieh (Co-Chairman of Committee) Andrew )ash (Member) Frank Dale Morgan (Member) John H. pang (Head...-axis z-plane Figure 4. Geometrv and crystallograpiuc orienration of negative crystal developed on m-plane of quartz dissoived in a weak basic solunon. After Gratz and others (1990). 12 Profiles F F S- Slow Dissolving Plane F-Fast Dissolvmg Plane l...

Bowman, James Albert

1992-01-01T23:59:59.000Z

254

X-ray-diffraction determination of the Ni-dopant site in single-crystal YBa2Cu3O7-?  

Science Journals Connector (OSTI)

Anomalous dispersive x-ray-diffraction measurements have determined the dopant-site distribution in Ni-doped single crystals of the high-temperature superconductor YBa2Cu3O7-?. The data from a YBa2(Cu0.83Ni0.17)3O7-? crystal show that over 95% of the Ni dopants occupy the Cu(2) site in the copper oxide planes, with negligible occupation of the Cu(1) copper oxide chain sites. General guidelines are presented for selecting the most effective hkl diffraction planes for measuring dopant concentration profiles. Direct measurement of the energy dependence of the dopant atomic scattering forces is also demonstrated.

S. A. Hoffman; M. A. Castro; G. C. Follis; S. M. Durbin

1994-05-01T23:59:59.000Z

255

Use of evaporative fractional crystallization in the pretreatment process of multi-salt single shell tank Hanford nuclear wastes.  

E-Print Network [OSTI]

??The purpose of the work described in this thesis was to explore the use of fractional crystallization as a technology that can be used to… (more)

Nassif, Laurent

2007-01-01T23:59:59.000Z

256

High-quality quartz single crystals for high-energy-resolution inelastic X-ray scattering analyzers  

Science Journals Connector (OSTI)

High-quality quartz (-SiO2) crystals are characterized, and their use for inelastic X-ray scattering analyzers is presented and discussed.

H?nnicke, M.G.

2013-06-07T23:59:59.000Z

257

Bridgman Growth of Large SrI2:Eu2+ Single Crystals: A High-performance Scintillator for Radiation Detection Applications  

SciTech Connect (OSTI)

Single-crystal strontium iodide (SrI2) doped with relatively high levels (e.g., 3 - 6 %) of Eu2+ exhibits characteristics that make this material superior, in a number of respects, to other scintillators that are currently used for radiation detection. Specifically, SrI2:Eu2+ has a light yield that is significantly higher than LaBr3:Ce3+ -a currently employed commercial high-performance scintillator. Additionally, SrI2:Eu2+ is characterized by an energy resolution as high as 2.6% at the 137Cs gamma-ray energy of 662 keV, and there is no radioactive component in SrI2:Eu2+ - unlike LaBr3:Ce3+ that contains 138La. The Ce3+-doped LaBr3 decay time is, however, faster (30 nsec) than the 1.2 sec decay time of SrI2:Eu2+. Due to the relatively low melting point of strontium iodide (~515 oC), crystal growth can be carried out in quartz crucibles by the vertical Bridgman technique. Materials-processing and crystal-growth techniques that are specific to the Bridgman growth of europium-doped strontium iodide scintillators are described here. These techniques include the use of a porous quartz frit to physically filter the molten salt from a quartz antechamber into the Bridgman growth crucible and the use of a bent or bulb grain selector design to suppress multiple grain growth. Single crystals of SrI2:Eu2+ scintillators with good optical quality and scintillation characteristics have been grown in sizes up to 5.0 cm in diameter by applying these techniques. Other aspects of the SrI2:Eu2+ crystal-growth methods and of the still unresolved crystal-growth issues are described here.

Boatner, Lynn A [ORNL; Ramey, Joanne Oxendine [ORNL; Kolopus, James A [ORNL; Hawrami, Rastgo [Radiation Monitoring Devices, Watertown, MA; Higgins, William [Radiation Monitoring Devices, Watertown, MA; Van Loef, Edgar [Radiation Monitoring Devices, Watertown, MA; Glodo, J. [Radiation Monitoring Devices, Watertown, MA; Shah, Kanai [Radiation Monitoring Devices, Watertown, MA; Bhattacharya, P. [Fisk University, Nashville, TN; Tupitsyn, E [Fisk University, Nashville, TN; Groza, Michael [Fisk University, Nashville, TN; Burger, Arnold [Fisk University, Nashville, TN

2013-01-01T23:59:59.000Z

258

SINGLE CRYSTAL SURFACE ENGINEERING  

E-Print Network [OSTI]

] ~ 310 [GPa] Phase g - Siebörger et al. [001] [111] #12;EPFL LASER CLADDING PROCESS Substrate Clad Remelted zone Vb Deposit G,VS LASER CLADDING PROCESS #12;EPFL b primary phaseg primary phase EPITAXY MCr CLADDING OF MCrAlY ON CMSX 4 #12;EPFL DENDRITE BRANCH SELECTION [100] [001] [010] [001] [010] [100] Laser

Cambridge, University of

259

Thermodynamic and transport properties of single-crystal Yb{sub 14}MnSb{sub 11}  

SciTech Connect (OSTI)

Relatively large (up to 250 mg) single crystals of the intermetallic compound Yb{sub 14}MnSb{sub 11} have been prepared by a flux-growth technique. The results of thermodynamic and transport measurements of these samples are presented. The compound orders ferromagnetically at approximately T{sub C}=53{plus_minus}1K, with a magnetization consistent with the assignment Mn{sup 3+} (3d{sup 4}) and Yb{sup 2+} (4f{sup 14}). The Mn moments are local in nature, with the full effective and saturated moment of the Hund{close_quote}s rule spin-only ground state. The electrical resistivity has a metallic temperature dependence, with only a modest anisotropy. Room-temperature values of the resistivity are relatively high for an intermetallic compound: 1630{plus_minus}160 {mu}{Omega}cm and 1250{plus_minus}130 {mu}{Omega}cm for currents flowing approximately parallel and perpendicular to the {ital c} axis, respectively. There is a distinct loss of spin-disorder scattering in the resistivity at T{sub C}. From the heat capacity, a rough estimation of the magnetic entropy gives {Delta}S{sub M}{approx}12.1 J/mol K, the value in reasonable agreement with the expected {Delta}S{sub M}{approx}R ln 5 from the assignment of these moments. All of these data are consistent with a picture of Mn{sup 3+} local moments being coupled via conduction electrons. To this end, Yb{sub 14}MnSb{sub 11} appears to be analogous to local-moment rare-earth intermetallic compounds, and may point the way toward a class of 3d Kondo lattice compounds. {copyright} {ital 1999} {ital The American Physical Society}

Fisher, I.R.; Wiener, T.A.; Budko, S.L.; Canfield, P.C. [Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)] [Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Chan, J.Y.; Kauzlarich, S.M. [Department of Chemistry, One Shields Avenue, University of California, Davis, California 95616 (United States)] [Department of Chemistry, One Shields Avenue, University of California, Davis, California 95616 (United States)

1999-06-01T23:59:59.000Z

260

Spin liquid in a single crystal of the frustrated diamond lattice antiferromagnet CoAl2O4  

Science Journals Connector (OSTI)

We study the evidence for spin liquid in the frustrated diamond lattice antiferromagnet CoAl2O4 by means of single-crystal neutron scattering in zero and applied magnetic fields. The magnetically ordered phase appearing below TN=8 K remains nonconventional down to 1.5 K. The magnetic Bragg peaks at the q=0 positions are broad and their line shapes have strong Lorentzian contributions. Additionally, the peaks are connected by weak diffuse streaks oriented along the ?111? directions. The observed short-range magnetic correlations are explained within the spiral spin-liquid model. The specific shape of the energy landscape of the system, with an extremely flat energy minimum around q=0 and many low-lying excited spiral states with q=?111?, results in thermal population of this manifold at finite temperatures. The agreement between the experimental results and the spiral spin-liquid model is only qualitative, indicating that microstructure effects might be important to achieve quantitative agreement. Application of a magnetic field significantly perturbs the spiral spin-liquid correlations. The magnetic peaks remain broad but acquire more Gaussian line shapes and increase in intensity. The 1.5 K static magnetic moment increases from 1.58 ?B/Co at zero field to 2.08 ?B/Co at 10 T. The magnetic excitations appear rather conventional at zero field. Analysis using classical spin-wave theory yields values of the nearest- and next-nearest-neighbor exchange parameters J1=0.92(1) meV and J2=0.101(2) meV and an additional anisotropy term D=?0.0089(2) meV for CoAl2O4. In the presence of a magnetic field, the spin excitations broaden considerably and become nearly featureless at the zone center.

O. Zaharko; N. B. Christensen; A. Cervellino; V. Tsurkan; A. Maljuk; U. Stuhr; C. Niedermayer; F. Yokaichiya; D. N. Argyriou; M. Boehm; A. Loidl

2011-09-06T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Measurement of the Young's modulus and internal friction of single crystal and polycrystalline copper, and copper-graphite composites as a function of temperature and orientation  

E-Print Network [OSTI]

MEASUREMENT OF THE YOUNG'S MODULUS AND INTERNAL FRICTION OF SINGLE CRYSTAL AND POLYCRYSTALLINE COPPER, AND COPPER- GRAPHITE COMPOSITES AS A FUNCTION OF TEMPERATURE AND ORIENTATION A Thesis by S teven Norman Wicks trom Submitted... AND POLYCRYSTALLINE COPPER, AND COPPER- GRAPHITE COMPOSITES AS A FUNCTION OF TEMPERATURE AND ORIENTATION A Thesis by Steven Norman Wickstrom Approved as to style and content by: A(J ~a Alan Wolfenden (Chairman of Committee) Don E. Bray (Member) Donald G...

Wickstrom, Steven Norman

2012-06-07T23:59:59.000Z

262

Synthesis, single-crystal structure, and optical absorption of Rb{sub 2}Th{sub 7}Se{sub 15}  

SciTech Connect (OSTI)

The compound Rb{sub 2}Th{sub 7}Se{sub 15} has been synthesized by the solid-state reaction at 1273 K of Th, Rb{sub 2}Se{sub 3}, Se, and Ge, and its structure has been determined by single-crystal X-ray diffraction methods. Red crystals of Rb{sub 2}Th{sub 7}Se{sub 15} crystallize at 100(2) K with four formula units in a new structure type in the monoclinic space group C{sub 2h}{sup 5}?P2{sub 1}/c. The structure is three-dimensional and comprises Rb and Th atoms coordinated by Se atoms to form nine-, eight-, and seven-coordinate polyhedra. Infinite channels that contain Rb atoms are present. Crystals of Rb{sub 2}Th{sub 7}Se{sub 15} are red in color; an indirect band gap of 1.83 eV was derived from single-crystal optical measurements. - Graphical abstract: Structure of Rb{sub 2}Th{sub 7}Se{sub 15} viewed down the b-axis. Display Omitted - Highlights: • The new compound Rb{sub 2}Th{sub 7}Se{sub 15} was synthesized at 1273 K from the elements in the presence of Ge. • The structures of the two known Rb/Th/Se compounds, RbTh{sub 2}Se{sub 6} and Rb{sub 2}Th{sub 7}Se{sub 15}, differ markedly. • Optical measurements establish the band gap of Rb{sub 2}Th{sub 7}Se{sub 15} to be indirect with a value of 1.83 eV.

Koscielski, Lukasz A.; Pozzi, Eric A.; Van Duyne, Richard P.; Ibers, James A., E-mail: ibers@chem.northwestern.edu

2013-09-15T23:59:59.000Z

263

Abstract. --The density matrix formalism is applied to the interpretation of Mossbauer spectra of single crystals of K3Fe(CN) taken with polarized y-radiation to find the average electric hyper-  

E-Print Network [OSTI]

of single crystals of K3Fe(CN)« taken with polarized y-radiation to find the average electric hyper- fine also. By a properly chosen set of measurements sites. A MOSSBAUER STUDY OF THE ELECTRIC HYPERFINE

Boyer, Edmond

264

The equilibrium concentration of hydrogen atoms ahead of a mixed mode I-mode III crack tip in single crystal iron  

SciTech Connect (OSTI)

Calculations of the equilibrium hydrogen concentration profiles about a mixed ode I-mode III crack in single crystal iron were performed. Both material anisotropy and the tetragonal nature of the distortion induced in the iron crystal structure by interstitial hydrogen were incorporated. Results show that, unlike the case of a spherical distortion, a strong coupling exists between the strain field of the interstitial hydrogen and the stress field of the crack for orientations of the crack plane that are not coincident with the cube axes of the lattice. As a result, the predicated enhancement of hydrogen in the crack tip region increases with increasing levels of mode III loading for those orientations. The results may help reconcile conflicting observations concerning the potential role of shear stresses in hydrogen embrittlement and preferential cracking of grains ahead of loaded crack tips in sustained load cracking experiments.

Zhang, T.Y.; Hack, J.E. [Yale Univ., New Haven, CT (United States). Dept. of Mechanical Engineering

1999-01-01T23:59:59.000Z

265

Broadband colored-crescent generation in a single {beta}-barium-borate crystal by intense femtosecond pulses  

SciTech Connect (OSTI)

A visible colored crescent with a bandwidth broader than 220 nm is observed experimentally by loosely focused femtosecond pulses in a bulk quadratic nonlinear crystal ({beta}-BBO crystal) at certain incident angles. Through the analysis based on a simple collinear phase-matching model, we suggest that the colored crescent might be the coexistence of spontaneous parametric down-conversions (SPDCs) in the infrared range and the corresponding efficient second-order harmonic generations (SHGs) that occur in a wide spectrum. We further provide a possible mechanism for the SHG process in which the phase-mismatching angles of the frequency doubling of SPDCs in {beta}-BBO crystal are assumed to be compensated by the strong diffraction effect during the self-focusing process of the generated intense SPDC signals.

Wang, L.; Fan, Y. X.; Zhu, H.; Yan, Z. D.; Zhu, S. N.; Wang, Z. L. [Department of Physics and National Laboratory of Solid State Microstructures, Nanjing University, 210093 Nanjing (China); Zeng, H. [State Key Laboratory of Precision Spectroscopy, East China Normal University, 200062 Shanghai (China); Wang, H.-T. [Department of Physics and National Laboratory of Solid State Microstructures, Nanjing University, 210093 Nanjing (China); School of Physics, Nankai University, 300071 Tianjin (China)

2011-12-15T23:59:59.000Z

266

Magnetic structure of Sr{sub 2}Fe{sub 2}O{sub 5} brownmillerite by single-crystal Mössbauer spectroscopy  

SciTech Connect (OSTI)

In order to determine orientation of the Fe{sup 3+} magnetic moments and electric field gradient (efg) axes in the brownmillerite-type strontium ferrite structure for both iron sublattices where the efg tensor is not axially symmetric, the Mössbauer spectra of powdered and oriented single-crystal Sr{sub 2}Fe{sub 2}O{sub 5} were analyzed by solving the complete Hamiltonian for hyperfine interactions in the excited and ground states of the {sup 57}Fe nuclei. The magnetic moments of both octahedrally and tetrahedrally coordinated iron cations lie on the ac-plane of the orthorhombic unit cell and are parallel to the shortest c-axis, whilst the main efg axes are parallel to the longest crystallographic axis, b. This orientation is similar to that in Ca{sub 2}Fe{sub 2}O{sub 5}, in spite of the structural differences of strontium and calcium ferrite brownmillerites at low temperatures. - Graphical abstract: Mössbauer spectra of powdered and oriented single-crystal Sr{sub 2}Fe{sub 2}O{sub 5}, analyzed by solving the complete Hamiltonian for hyperfine interactions in the excited and ground states of the {sup 57}Fe nuclei, show that the magnetic moments of both octahedrally and tetrahedrally coordinated iron cations are parallel to the shortest c-axis of the orthorhombic brownmillerite unit cell . Display Omitted - Highlights: • Single-crystal Mössbauer spectroscopy is used to study magnetic structure of Sr{sub 2}Fe{sub 2}O{sub 5}. • Complete Hamiltonian for hyperfine interactions in excited and ground states was solved. • Fe{sup 3+} magnetic moments are parallel to the shortest crystallographic axis c. • The orientation of nuclear electric field gradient is similar to that in Ca{sub 2}Fe{sub 2}O{sub 5}.

Waerenborgh, J.C. [UCQR, IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa, CFMC-UL, Estrada Nacional 10, 2686-953 Sacavém (Portugal); Tsipis, E.V. [UCQR, IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa, CFMC-UL, Estrada Nacional 10, 2686-953 Sacavém (Portugal); Department of Materials and Ceramic Engineering, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Auckett, J.E.; Ling, C.D. [School of Chemistry, The University of Sydney, Sydney 2006 (Australia); Kharton, V.V., E-mail: kharton@ua.pt [Department of Materials and Ceramic Engineering, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Institute of Solid State Physics RAS, Chernogolovka 142432, Moscow Region (Russian Federation)

2013-09-15T23:59:59.000Z

267

In situ dehydration behavior of zeolite-like pentagonite: A single-crystal X-ray study  

SciTech Connect (OSTI)

The structural modifications upon heating of pentagonite, Ca(VO)(Si{sub 4}O{sub 10}){center_dot}4H{sub 2}O (space group Ccm2{sub 1}, a=10.3708(2), b=14.0643(2), c=8.97810(10) A, V=1309.53(3) A{sup 3}) were investigated by in situ temperature dependent single-crystal X-ray structure refinements. Diffraction data of a sample from Poona district (India) have been measured in steps of 25 up to 250 Degree-Sign C and in steps of 50 Degree-Sign C between 250 and 400 Degree-Sign C. Pentagonite has a porous framework structure made up by layers of silicate tetrahedra connected by V{sup 4+}O{sub 5} square pyramids. Ca and H{sub 2}O molecules are extraframework occupants. Room temperature diffraction data allowed refinement of H positions. The hydrogen-bond system links the extraframework occupants to the silicate layers and also interconnects the H{sub 2}O molecules located inside the channels. Ca is seven-fold coordinated forming four bonds to O of the tetrahedral framework and three bonds to extraframework H{sub 2}O. The H{sub 2}O molecule at O9 showing a high displacement parameter is not bonded to Ca. The dehydration in pentagonite proceeds in three steps. At 100 Degree-Sign C the H{sub 2}O molecule at O8 was released while O9 moved towards Ca. As a consequence the displacement parameter of H{sub 2}O at O9 halved compared to that at room temperature. The unit-cell volume decreased to 1287.33(3) A{sup 3} leading to a formula with 3H{sub 2}O per formula unit (pfu). Ca remained seven-fold coordinated. At 175 Degree-Sign C Ca(VO)(Si{sub 4}O{sub 10}){center_dot}3H{sub 2}O transformed into a new phase with 1H{sub 2}O molecule pfu characterized by doubling of the c axis and the monoclinic space group Pn. Severe bending of specific T--O--T angles led to contraction of the porous three-dimensional framework. In addition, H{sub 2}O at O9 was expelled while H{sub 2}O at O7 approached a position in the center of the channel. The normalized volume decreased to 1069.44(9) A{sup 3}. The Ca coordination reduced from seven- to six-fold. At 225 Degree-Sign C a new anhydrous phase with space group Pna2{sub 1} but without doubling of c had formed. Release of H{sub 2}O at O7 caused additional contraction of T--O--T angles and volume reduction (V=1036.31(9) A{sup 3}). Ca adopted five-fold coordination. During heating excursion up to 400 Degree-Sign C this anhydrous phase remained preserved. Between room temperature and 225 Degree-Sign C the unit-cell volume decreased by 21% due to dehydration. The dehydration steps compare well with the thermo-gravimetric data reported in the literature. - Graphical abstract: Pentagonite structure at room temperature and at 225 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer We investigate the relationship between the removal of H{sub 2}O molecules and structural modifications of the framework of pentagonite. Black-Right-Pointing-Pointer Pentagonite undergoes phase transitions upon heating. Black-Right-Pointing-Pointer We analyze similarities and differences between pentagonite and related structures.

Danisi, Rosa Micaela, E-mail: rosa.danisi@krist.unibe.ch [Mineralogical Crystallography, Institute of Geological Sciences, University of Bern, Freiestrasse 3, Bern CH-3012 (Switzerland); Armbruster, Thomas; Lazic, Biljana [Mineralogical Crystallography, Institute of Geological Sciences, University of Bern, Freiestrasse 3, Bern CH-3012 (Switzerland)

2013-01-15T23:59:59.000Z

268

Scanning Josephson Tunneling Microscopy of Single Crystal Bi2Sr2CaCu2O8+delta with a Conventional Superconducting Tip  

SciTech Connect (OSTI)

We have performed both Josephson and quasiparticle tunneling in vacuum tunnel junctions formed between a conventional superconducting scanning tunneling microscope tip and overdoped Bi2Sr2CaCu2O8+ single crystals. A Josephson current is observed with a peak centered at a small finite voltage due to the thermal-fluctuation-dominated superconducting phase dynamics. Josephson measurements at different surface locations yield local values for the Josephson ICRN product. Corresponding energy gap measurements were also performed and a surprising inverse correlation was observed between the local ICRN product and the local energy gap.

Kimura, H.; Barber Jr., R. P.; Ono, S.; Ando, Yoichi; Dynes, Robert C.

2009-10-28T23:59:59.000Z

269

Rabi Waves and Peculiarities of Raman Scattering in Carbon Nanotubes, Produced by High Energy Ion Beam Modification of Diamond Single Crystals  

E-Print Network [OSTI]

QED-model for multichain coupled qubit system, proposed in \\cite{Part1}, was confirmed by Raman scattering studies of carbon zigzag-shaped nanotubes, produced by high energy ion beam modification of natural diamond single crystals. New quantum optics phenomenon - Rabi waves - has been experimentally identified for the first time. Raman spectra in perfect quasi-1D carbon nanotubes are quite different in comparison with well known Raman spectra in 2D carbon nanotubes of larger diameter. They characterized by vibronic mode of Su-Schriffer-Heeger $\\sigma$-polaron lattice and its revival part in frequency representation, which is the consequence of Rabi wave packet formation.

Dmitry Yearchuck; Alla Dovlatova

2011-03-06T23:59:59.000Z

270

Modifications of the surface properties of metals by oxide overlayers: 1, Oxidized zirconium deposited on the Pt(100) single crystal surface  

SciTech Connect (OSTI)

Metallic zirconium was deposited on a single crystal Pt(100) surface by thermal evaporation in UHV conditions. The deposit was oxidized by exposure to oxygen immediately after deposition. Oxidized zirconium was found to grow on the platinum ace by the layer-by-layer mechanism. The adsorption of carbon monoxide on the surface was studied as a function of the zirconium coverage. The results show that oxidized zirconium forms a chemically inert layer which blocks the adsorptive sites of the underlying platinum substrate. The properties of the free Pt surface were unaffected by the presence of the oxidized zirconium layer.

Bardi, U.; Ross, P.N.

1986-06-01T23:59:59.000Z

271

Hydrohalite in cold sea ice: Laboratory observations of single crystals, surface accumulations, and migration rates under a temperature  

E-Print Network [OSTI]

April 2009; published 17 July 2009. [1] When NaCl precipitates out of a saturated solution, it forms it instead precipitates as the dihydrate ``hydrohalite,'' NaCl Á 2H2O. When sea ice is cooled, hydrohalite begins to precipitate within brine inclusions at about �23°C. In this work, hydrohalite crystals

Warren, Stephen

272

PHONON DISPERSION CURVES OF ORDERED PHASES OF T.B.B.A. Abstract. --The lattice dynamics of a deuterated single crystal of T.B.B.A. have been measured  

E-Print Network [OSTI]

of a deuterated single crystal of T.B.B.A. have been measured by mean of inelastic neutron scattering of the molecules. Previous neutron inelastic scattering measurements have been done on non-deuterated single of a melting of the terminal aliphatic chains. So neutron coherent inelastic scattering measure- ments have

Boyer, Edmond

273

Mixed crystal organic scintillators  

DOE Patents [OSTI]

A mixed organic crystal according to one embodiment includes a single mixed crystal having two compounds with different bandgap energies, the organic crystal having a physical property of exhibiting a signal response signature for neutrons from a radioactive source, wherein the signal response signature does not include a significantly-delayed luminescence characteristic of neutrons interacting with the organic crystal relative to a luminescence characteristic of gamma rays interacting with the organic crystal. According to one embodiment, an organic crystal includes bibenzyl and stilbene or a stilbene derivative, the organic crystal having a physical property of exhibiting a signal response signature for neutrons from a radioactive source.

Zaitseva, Natalia P; Carman, M Leslie; Glenn, Andrew M; Hamel, Sebastien; Hatarik, Robert; Payne, Stephen A; Stoeffl, Wolfgang

2014-09-16T23:59:59.000Z

274

Growth of 5 mm GaN Single Crystals at 750 °C from an Na?Ga Melt  

Science Journals Connector (OSTI)

Laser diodes using GaN-based III?V nitrides have been developed, and nitride semiconductor devices are now of considerable interest. ... When the inclusions were exposed to air, they reacted with water vapor in air and produced sodium hydroxide and small gallium metal droplets at the fracture surface of the crystal. ... The solubility of nitrogen in liquid sodium is extremely low (7.1 × 10-9 mol % N at 600 °C). ...

Masato Aoki; Hisanori Yamane; Masahiko Shimada; Seiji Sarayama; Francis J. DiSalvo

2001-02-03T23:59:59.000Z

275

Features of the charge-transport mechanism in layered Bi{sub 2}Te{sub 3} single crystals doped with chlorine and terbium  

SciTech Connect (OSTI)

The temperature dependences (T = 5-300 K) of the resistivity in the plane of layers and in the direction perpendicular to the layers, as well as the Hall effect and the magnetoresistance (H < 80 kOe, T = 0.5-4.2 K) in Bi{sub 2}Te{sub 3} single crystals doped with chlorine and terbium, are investigated. It is shown that the doping of Bi{sub 2}Te{sub 3} with terbium atoms results in p-type conductivity and in increasing hole concentration. The doping of Bi{sub 2}Te{sub 3} with chlorine atoms modifies also the character of its conductivity instead of changing only the type from p to n. In the temperature dependence of the resistivity in the direction perpendicular to layers, a portion arises with the activation conductivity caused by the hopping between localized states. The charge-transport mechanism in Bi{sub 2}Te{sub 3} single crystals doped with chlorine is proposed.

Abdullaev, N. A., E-mail: anadir@azintex.com; Abdullaev, N. M.; Aliguliyeva, H. V.; Kerimova, T. G.; Mehdiyev, G. S. [National Academy of Sciences of Azerbaijan, Abdullaev Institute of Physics (Azerbaijan); Nemov, S. A. [St. Petersburg State Polytechnic University (Russian Federation)

2011-01-15T23:59:59.000Z

276

A single mutation of restriction endonuclease EcoRII led to a new crystal form that diffracts to 2.1 ? resolution  

Science Journals Connector (OSTI)

R88A, a mutant of restriction endonuclease EcoRII, has been crystallized in a different crystal form to that of the wild type. The mutant crystals diffract to 2.1 ? resolution.

Zhou, X.E.

2003-04-25T23:59:59.000Z

277

Single-crystal studies of the Chevrel-phase superconductor La{sub x}Mo{sub 6}Se{sub 8}. 2: Physical and superconducting properties  

SciTech Connect (OSTI)

Single crystals of La{sub x}Mo{sub 6}Se{sub 8} have been grown and some of their magnetic, transport, and superconducting properties studied. The electrical resistivity is characterized by its high value at room temperature, its low residual resistivity ratio, and a pronounced negative curvature at high temperatures. Comparison with the isostructural compounds Mo{sub 3}Se{sub 4} (Mo{sub 6}Se{sub 8}) and LaMo{sub 6}S{sub 8} shows that this behavior is due to structural as well as to extrinsic features (e.g., brittleness due to weak intercluster bondings). The position of the Fermi level near a peak of the density of states plays an important role in the normal-state physical properties, fixing the functional forms of both resistivity and magnetic susceptibility. The superconducting state is mainly characterized by a strong lanthanum concentration dependence of the critical temperature {Tc}, by quite definite granular effects, and by a very high critical field (H{sub c2}(0) {approximately} 55 T). The intragrain critical current density, as estimated by magnetic measurements, is relatively high (4 {times} 10{sup 4} A/cm{sup 2} at zero field and 1.7 K), three times larger than the one obtained for the void compound Mo{sub 3}Se{sub 4}. The fact is due to a higher density of pinning centers in the ternary compound because of microstructural features such as microcracks or crystal defects caused by the extreme brittleness of the crystals.

Pena, O.; Le Berre, F.; Padiou, J.; Marchand, T. [Univ. de Rennes I (France). Chimie du Solide et Inorganique Moleculaire] [Univ. de Rennes I (France). Chimie du Solide et Inorganique Moleculaire; Horyn, R.; Wojakowski, A. [Polish Academy of Sciences, Wroclaw (Poland). Inst. of Low Temperature and Structure Research] [Polish Academy of Sciences, Wroclaw (Poland). Inst. of Low Temperature and Structure Research

1998-03-01T23:59:59.000Z

278

Far-infrared transmission study of single-crystal Bi sub 2 Sr sub 2 Ca sub 1 Cu sub 2 O sub x superconductors  

SciTech Connect (OSTI)

We report the infrared transmission of free-standing single crystals of the high-temperature superconductor Bi{sub 2}Sr{sub 2}Ca{sub 1}Cu{sub 2}O{sub {ital x}}, at temperatures between 25 and 300 K and at frequencies covering the range of 1.5{ital k}{sub {ital B}T{ital c}}{l angle}{h bar}{omega}{lt}12{ital k}{sub {ital B}T{ital c}}. The normal-state Drude relaxation rate follows a linear temperature dependence {h bar}/{tau}=3{ital k}{sub {ital B}T}. In the superconducting state there is no indication of a transmission peak, which characterizes a superconducting gap in the optical conductivity. We suggest that a strong pair-breaking interaction is responsible for this null result.

Forro, L.; Carr, G.L.; Williams, G.P.; Mandrus, D.; Mihaly, L. (Department of Physics, State University of New York, Stony Brook, NY (USA) Department of Physics, University of Florida, Gainesville, FL (USA) National Synchroton Light Source, Brookhaven National Laboratory, Upton, NY (USA))

1990-10-08T23:59:59.000Z

279

Effect of electron irradiation on superconductivity in single crystals of Ba(Fe1-xRux)2As2 (x=0.24)  

SciTech Connect (OSTI)

A single crystal of isovalently substituted Ba(Fe1?xRux)2As2 (x=0.24) is sequentially irradiated with 2.5 MeV electrons up to a maximum dose of 2.1×1019 e?/cm2. The electrical resistivity is measured in situ at T=22??K during the irradiation and ex situ as a function of temperature between subsequent irradiation runs. Upon irradiation, the superconducting transition temperature Tc decreases and the residual resistivity ?0 increases. We find that electron irradiation leads to the fastest suppression of Tc compared to other types of artificially introduced disorder, probably due to the strong short-range potential of the pointlike irradiation defects. A more detailed analysis within a multiband scenario with variable scattering potential strength shows that the observed Tc versus ?0 is fully compatible with s± pairing, in contrast to earlier claims that this model leads to a too rapid suppression of Tc with scattering.

Prozorov, Ruslan [Ames Laboratory; Konczykowski, M [Laboratoire des Solides Irradies; Tanatar, Makariy A. [Ames Laboratory; Thaler, Alexander [Ames Laboratory; Budko, Serguei L [Ames Laboratory; Canfield, Paul C [Ames Laboratory; Mishra, V [Argonne National Laboratory; Hirschfeld, P J [University of Florida

2014-11-01T23:59:59.000Z

280

Surface structure of coadsorbed benzene and carbon monoxide on the rhodium(111) single crystal analyzed with low-energy electron diffraction intensities  

SciTech Connect (OSTI)

The first structural analysis of a molecular coadsorbate system is presented. Mutual reordering and site shifting are found to occur for benzene and CO coadsorbed in a (/sub 13//sup 31/) lattice on Rh(111). This low-energy electron diffraction (LEED) intensity analysis yields the first confirmed hollow-site adsorption of CO on a single-crystal metal surface, with a C-O bond length expanded by 0.06 +/- 0.05 A from the gas phase. The flat-lying benzene is found centered over hcp-type hollow sites with a strong Kekule-type distortion: C-C bond lengths alternate between 1.33 +/- 0.15 A (hydrogen positions were not determined). This suggests the possibility of a 1,3,5-cyclohexatriene species being formed. The Rh-C bond length is 2.35 +/- 0.05 A for benzene and 2.16 +/- 0.04 A for CO.

Van Hove, M.A.; Lin, R.F.; Somorjai, G.A.

1986-05-14T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


281

Temperature dependence of electrical properties of gallium-nitride bulk single crystals doped with Mg and their evolution with annealing  

Science Journals Connector (OSTI)

Comprehensive studies of the electrical properties of Mg-doped bulk GaN crystals grown by high-pressure synthesis were performed as a function of temperature up to 750?°C. Annealing of the samples in nitrogen ambient modifies qualitatively their resistivity values ? and the ?(T) variation. It was found that our material is characterized by a high concentration of oxygen-related donors and that the charge transport in the studied samples is determined by two types of states one of shallow character (Mg-related state E A ?0.15? eV ) and the second one much more deep E 2 ?0.95? eV (above the valence band). Depending on the effective concentration of either states different resistivities ? can be observed: lower resistivity (?10 6 ??? cm at ambient temperature) in samples with dominant E 2 states. For the first type of samples annealing at T ann <500?° C leads to a decrease of their resistivity and is associated with an increase of the effective concentration of the shallow Mg acceptors. Annealing of both types of samples at temperatures between 600 and 750?°C leads to an increase of the deep state concentration. The presence of hydrogen ambient during annealing of the low-resistivity samples strongly influences their properties. The increase of the sample resistivity and an appearance of a local vibrational mode of hydrogen at 3125 cm?1 were observed. These effects can be removed by annealing in hydrogen-free ambient.

E. Litwin-Staszewska; T. Suski; R. Piotrzkowski; I. Grzegory; M. Bockowski; J. L. Robert; L. Ko?czewicz; D. Wasik; E. Kami?ska; D. Cote; B. Clerjaud

2001-01-01T23:59:59.000Z

282

Epitaxial growth of perfluoropentacene films with predefined molecular orientation: A route for single-crystal optical studies  

Science Journals Connector (OSTI)

Using atomic-force microscopy and x-ray diffraction we show that perfluoropentacene (C22F14, PFP) forms long-range ordered, epitaxial films on KCl(100) and NaF(100) cleavage planes. On both substrates the films adopt the same crystalline bulk phase, but surprisingly exhibit quite different molecular orientations, being upright oriented on NaF and recumbent oriented on KCl. Accompanied thermal desorption spectroscopy measurements indicate the absence of a stabilized seed layer, like on metals, hence suggesting that in both cases the PFP films are stabilized by an electrostatic point-in-line relationship between the outermost fluorine atoms and the alkali cations of the alkali halide surfaces. Furthermore, the transparency of both substrates was utilized to perform detailed transmission UV/Vis spectroscopy and polarized optical microscopy measurements along well-defined crystallographic directions. From these data the orientation of transition dipole moments of the various optical excitations were experimentally determined and a directional anisotropic exciton coupling was observed, which is attributed to the asymmetric molecular packing motif within the (100) plane of the PFP crystal lattice.

Tobias Breuer and Gregor Witte

2011-04-18T23:59:59.000Z

283

Infiltrating a thin or single layer opal with an atomic vapour: sub-doppler signals and crystal optics  

E-Print Network [OSTI]

Artificial thin glass opals can be infiltrated with a resonant alkali-metal vapour, providing novel types of hybrid systems. The reflection at the interface between the substrate and the opal yields a resonant signal, which exhibits sub-Doppler structures in linear spectroscopy for a range of oblique incidences. This result is suspected to originate in an effect of the three-dimensional confinement of the vapour in the opal interstices. It is here extended to a situation where the opal is limited to a few or even a single layer opal film, which is a kind of bidimensional grating. We have developed a flexible one-dimensional layered optical model, well suited for a Langmuir-Blodgett opal. Once extended to the case of a resonant infiltration, the model reproduces quick variations of the lineshape with incidence angle or polarization. Alternately, for an opal limited to a single layer of identical spheres, a three-dimensional numerical calculation was developed. It predicts crystalline anisotropy, which is demon...

Moufarej, Elias; Zabkov, Ilya; Laliotis, Athanasios; Ballin, Philippe; Klimov, Vasily; Bloch, Daniel

2014-01-01T23:59:59.000Z

284

High-pressure single-crystal X-ray diffraction facilities on station 9.8 at the SRS Daresbury Laboratory - hydrogen location in the high-pressure structure of ethanol  

Science Journals Connector (OSTI)

A new high-pressure single-crystal diffraction facility constructed on station 9.8 at the Synchrotron Radiation Source, Daresbury Laboratory, is described. Initial results on the low-melting-point compound ethanol are presented; diffraction data were of sufficient quality to enable H-atoms to be located.

Allan, D.R.

2001-01-01T23:59:59.000Z

285

Magnetic field dependence of the coherence length and penetration depth of MgB2 single crystals T. Klein,1,2 L. Lyard,1 J. Marcus,1 Z. Holanova,1 and C. Marcenat3  

E-Print Network [OSTI]

Magnetic field dependence of the coherence length and penetration depth of MgB2 single crystals T with a phenomenological Ginzburg-Landau model introducing field dependent parameters i.e., penetration depth and which scattering form factor, and muon spin relaxation rate. DOI: 10.1103/PhysRevB.73.184513 PACS number s : 74

Boyer, Edmond

286

Electronic structure of a PbFe1/2Nb1/2O3 single crystal in the ferroelectric and paraelectric states, according to X-Ray photoelectron spectroscopy data and first principle calculations  

Science Journals Connector (OSTI)

Electronic structure of the PbFe1/2Nb1/2O3 single crystal is studied by means of X-ray photoelectron spectroscopy on an ESCALAB 250 system and first principle FEFF9 at temperatures of 296 and 403 K.

A. T. Kozakov; O. E. Polozhentsev…

2012-10-01T23:59:59.000Z

287

Rabi Wave Packets and Peculiarities of Raman Scattering in Carbon Nanotubes, Produced by High Energy Ion Beam Modification of Diamond Single Crystals  

E-Print Network [OSTI]

QED-model for multichain coupled qubit system, proposed in \\cite{Part1}, was confirmed by Raman scattering studies of quasi-1D carbon zigzag-shaped nanotubes (CZSNTs), produced by high energy ion beam modification of natural diamond single crystals. Multichain coupled qubit system represents itself Su-Schriffer-Heeger $\\sigma$-polaron lattice, formed in CZSNTs plus quantized external electromagnetic (EM) field. New quantum optics phenomenon - Rabi waves, predicted in \\cite{Slepyan_Yerchak} has experimentally been identified for the first time. It is shown, that Raman spectra in quasi-1D CZSNTs are quite different in comparison with well known Raman spectra in 2D those ones. They characterized by semiclassical consideration by the only one vibronic mode of Su-Schriffer-Heeger $\\sigma$-polaron lattice instead of longitudinal and transverse optical phonon $G^+$ and $G^-$modes and the out-of-plane radial breathing mode, which are observed in Raman spectra of 2D single wall nanotubes. It is consequence of 2D - 1D transition in all physical properties of nanotubes. It is shown, that strong electron-photon coupling takes place in CZSNTs by interaction with EM-field and quantum nature of EM-field has to be taken into account. It has been done for the first time in stationary spectroscopy at all. All optical spectra, in particular, Raman spectra are registered by usual stationary measurement technique in nonequilibrium conditions, which are the consequence of Rabi wave packets' formation. It leads in its turn to appearance of additional lines, corresponding to revival part of inversion dependence of joint EM-field + matter system in frequency representation.

Dmitry Yearchuck; Alla Dovlatova

2011-05-26T23:59:59.000Z

288

Polarized X-Ray Absorption Spectroscopy of Single-Crystal Mn(V) Complexes Relevant to the Oxygen-Evolving Complex of Photosystem II  

SciTech Connect (OSTI)

High-valent Mn-oxo species have been suggested to have a catalytically important role in the water splitting reaction which occurs in the Photosystem II membrane protein. In this study, five- and six-coordinate mononuclear Mn(V) compounds were investigated by polarized X-ray absorption spectroscopy in order to understand the electronic structure and spectroscopic characteristics of high-valent Mn species. Single crystals of the Mn(V)-nitrido and Mn(V)-oxo compounds were aligned along selected molecular vectors with respect to the X-ray polarization vector using X-ray diffraction. The local electronic structure of the metal site was then studied by measuring the polarization dependence of X-ray absorption near-edge spectroscopy (XANES) pre-edge spectra (1s to 3d transition) and comparing with the results of density functional theory (DFT) calculations. The Mn(V)-nitrido compound, in which the manganese is coordinated in a tetragonally distorted octahedral environment, showed a single dominant pre-edge peak along the MnN axis that can be assigned to a strong 3dz2-4pz mixing mechanism. In the square pyramidal Mn(V)-oxo system, on the other hand, an additional peak was observed at 1 eV below the main pre-edge peak. This component was interpreted as a 1s to 3dxz,yz transition with 4px,y mixing, due to the displacement of the Mn atom out of the equatorial plane. The XANES results have been correlated to DFT calculations, and the spectra have been simulated using a TD (time-dependent)-DFT approach. The relevance of these results to understanding the mechanism of the photosynthetic water oxidation is discussed.

Yano, J.K.; Robblee, J.; Pushkar, Y.; Marcus, M.A.; Bendix, J.; Workman, J.M.; Collins, T.J.; Solomon, E.I.; George, S.D.; Yachandra, V.K.; /LBL, Berkeley /Copenhagen U. /Stanford U., Chem. Dept. /SLAC, SSRL

2007-10-16T23:59:59.000Z

289

Electrical properties of Pb{sub 1-x}Mn{sub x}Te single crystals with an excess of tellurium  

SciTech Connect (OSTI)

The effect of excess Te atoms (as high as 0.5 at %) and thermal treatment at 473 K for 120 h on the electrical conductivity {sigma}, the thermopower coefficient {alpha}, and the Hall coefficient R of Pb{sub 0.96}Mn{sub 0.04}Te single crystals in the temperature range {approx}77-300 K is investigated. It is shown that excess atoms of tellurium predominantly act as acceptor impurity centers at low concentrations in unannealed samples and form antisite defects at relatively high concentrations (0.05 at % or higher) being located mainly in vacancies of the lead sublattice, and decrease the hole concentration. As a result of annealing, certain lattice defects (for example, deformational) are healed, and the accommodation process for Te atoms at lead-sublattice vacancies is intensified. These processes substantially affect the values of the electrical parameters, their temperature dependences, as well as the sign of the thermopower and Hall coefficients of the samples.

Bagieva, G. Z., E-mail: bagieva-gjulandam@rambler.ru; Abdinova, G. D.; Mustafayev, N. B.; Abdinov, D. Sh. [National Academy of Sciences of Azerbaijan, Abdullaev Institute of Physics (Azerbaijan)

2013-03-15T23:59:59.000Z

290

Soft x-ray appearance potential spectroscopy study of MgO (100) and ?-Al{sub 2}O{sub 3} (100) single crystals  

SciTech Connect (OSTI)

Soft x-ray appearance potential spectroscopy (SXAPS) measurements was used to measure on MgO (100) and ?-Al{sub 2}O{sub 3} (100) single crystals. Mg 1s, Al 1s, and O 1s SXAPS self-deconvoluted (SD) spectra were obtained. The features of the Mg 1s and O1s SD spectra are in fair agreement with those of the near-edge x-ray absorption fine structure spectra for an MgO thin film (3 ML) on Ag (100). This suggests that the SXAPS spectra reflect electronic states of the relaxed MgO (100) surface. The features of the Al 1s and O 1s SD spectra are in qualitative agreement with those of the electron energy-loss spectroscopy. The SXAPS SD spectra are discussed in terms of antibonding states and partial density of empty states obtained by theoretical calculations for MgO and ?-Al{sub 2}O{sub 3,} respectively. The present result suggests that the “approximate dipole selection rule” is applicable to the SXAPS spectra of MgO and ?-Al{sub 2}O{sub 3}, as well as 3d transition metal oxides.

Fukuda, Yasuo, E-mail: royfuku@rie.shizuoka.ac.jp; Sanada, Noriaki; Mochizuki, Sachie; Yatsuzuka, Ikuko [Research Institute of Electronics, Shizuoka University, Johoku 3-5-1, Naka-ku, Hamamatsu 432-8011 (Japan)

2013-11-15T23:59:59.000Z

291

Magnetic structures and interplay between rare-earth Ce and Fe magnetism in single-crystal CeFeAsO  

SciTech Connect (OSTI)

Neutron and synchrotron resonant x-ray magnetic scattering (RXMS) complemented by heat capacity and resistivity measurements reveal the evolution of the magnetic structures of Fe and Ce sublattices in a CeFeAsO single crystal. The RXMS of magnetic reflections at the Ce LII edge shows a magnetic transition that is specific to the Ce antiferromagnetic long-range ordering at TCe? 4 K with short-range Ce ordering above TCe, whereas neutron diffraction measurements of a few magnetic reflections indicate a transition at T?? 12 K with an unusual order parameter. Detailed order-parameter measurements on several magnetic reflections by neutrons show a weak anomaly at 4 K that we associate with the Ce ordering. The successive transitions at TCe and T? can also be clearly identified by two anomalies in heat capacity and resistivity measurements. The higher transition temperature at T?? 12 K is mainly ascribed to Fe spin reorientation transition, below which Fe spins rotate uniformly and gradually in the ab plane. The Fe spin reorientation transition and short-range Ce ordering above TCe reflect the strong Fe-Ce couplings prior to long-range ordering of the Ce. The evolution of the intricate magnetic structures in CeFeAsO going through T? and TCe is proposed.

Zhang, Qiang [Ames Laboratory; Tian, Wei [Ames Laboratory; Li, Haifeng [Ames Laboratory; Kim, Jong-Woo [Argonne Naitonal Laboratory; Yan, Jiaqiang [Ames Laboratory; McCallum, Robert William [Ames Laboratory; Lograsso, Thomas A. [Ames Laboratory; Zarestky, Jerel L. [Ames Laboratory; Budko, Sergey L. [Ames Laboratory; McQueeney, Robert J. [Ames Laboratory; Vaknin, David [Ames Laboratory

2013-11-27T23:59:59.000Z

292

Correlated vortex pinning in slightly orthorhombic twinned Ba(Fe1-xCox)2As2 single crystals: Possible shift of the vortex-glass/liquid transition  

SciTech Connect (OSTI)

The interest in twin-boundary (TB) planes as a source of vortex pinning has been recently renewed with the discovery of the new iron-arsenide pnictide superconductors. In the family of compounds Ba(Fe1-xCox)2As2 a structural transition from a tetragonal to orthorhombic lattice takes place for compounds with xsingle crystals. Using a scaling approach we are able to determine the angular regions where correlated or uncorrelated disorder prevails. In the tetragonal samples (x>xcr) there is no twinning and we find good agreement with the expected scaling function under uncorrelated disorder, with small anisotropy values similar to those reported in the literature. We show that in the orthorhombic samples (x

Bermudez, M. Marziali [Universidad de Buenos Aires; Pasquini, G. [Universidad de Buenos Aires; Budko, Sergey L. [Ames Laboratory; Canfield, Paul C. [Ames Laboratory

2013-02-28T23:59:59.000Z

293

Hydrogenation of the alpha,beta-Unsaturated Aldehydes Acrolein, Crotonaldehyde, and Prenal over Pt Single Crystals: A Kinetic and Sum-Frequency Generation Vibrational Spectroscopy Study  

SciTech Connect (OSTI)

Sum-frequency generation vibrational spectroscopy (SFG-VS) and kinetic measurements using gas chromatography have been used to study the surface reaction intermediates during the hydrogenation of three {alpha},{beta}-unsaturated aldehydes, acrolein, crotonaldehyde, and prenal, over Pt(111) at Torr pressures (1 Torr aldehyde, 100 Torr hydrogen) in the temperature range of 295K to 415K. SFG-VS data showed that acrolein has mixed adsorption species of {eta}{sub 2}-di-{sigma}(CC)-trans, {eta}{sub 2}-di-{sigma}(CC)-cis as well as highly coordinated {eta}{sub 3} or {eta}{sub 4} species. Crotonaldehyde adsorbed to Pt(111) as {eta}{sub 2} surface intermediates. SFG-VS during prenal hydrogenation also suggested the presence of the {eta}{sub 2} adsorption species, and became more highly coordinated as the temperature was raised to 415K, in agreement with its enhanced C=O hydrogenation. The effect of catalyst surface structure was clarified by carrying out the hydrogenation of crotonaldehyde over both Pt(111) and Pt(100) single crystals while acquiring the SFG-VS spectra in situ. Both the kinetics and SFG-VS showed little structure sensitivity. Pt(100) generated more decarbonylation 'cracking' product while Pt(111) had a higher selectivity for the formation of the desired unsaturated alcohol, crotylalcohol.

Kliewer, C.J.; Somorjai, G.A.

2008-11-26T23:59:59.000Z

294

Description and procedures for synchrotron radiation, small molecule, single crystal crystallography of plutonium complexes at ALS beamline 11.3.1  

E-Print Network [OSTI]

Description and Procedures for Synchrotron Radiation, Smallof RWA 1117. The RWA 1117 procedure for mounting radioactiveRadioactive Crystal Mounting Procedure: Equipment: Glove Box

Gorden, A.E.V.; Raymond, K.N.; Shuh, D.K.

2008-01-01T23:59:59.000Z

295

NMR relaxation study of the phase transitions and relaxation mechanisms of the alums MCr(SO{sub 4}){sub 2}.12H{sub 2}O (M=Rb and Cs) single crystals  

SciTech Connect (OSTI)

The physical properties and phase transition mechanisms of MCr(SO{sub 4}){sub 2}.12H{sub 2}O (M=Rb and Cs) single crystals have been investigated. The phase transition temperatures, NMR spectra, and the spin-lattice relaxation times T{sub 1} of the {sup 87}Rb and {sup 133}Cs nuclei in the two crystals were determined using DSC and FT NMR spectroscopy. The resonance lines and relaxation times of the {sup 87}Rb and {sup 133}Cs nuclei undergo significant changes at the phase transition temperatures. The sudden changes in the splitting of the Rb and Cs resonance lines are attributed to changes in the local symmetry of their sites, and the changes in the temperature dependences of T{sub 1} are related to variations in the symmetry of the octahedra of water molecules surrounding Rb{sup +} and Cs{sup +}. We also compared these {sup 87}Rb and {sup 133}Cs NMR results with those obtained for the trivalent cations Cr and Al in MCr(SO{sub 4}){sub 2}.12H{sub 2}O and MAl(SO{sub 4}){sub 2}.12H{sub 2}O crystals. - Graphical Abstract: The physical properties and phase transition mechanisms of MCr(SO{sub 4}){sub 2}.12H{sub 2}O (M=Rb, Cs, and NH{sub 4}) single crystals have been investigated. Highlights: > The physical properties and phase transition mechanisms of MCr(SO{sub 4}){sub 2}.12H{sub 2}O (M=Rb and Cs) crystals {yields} The NMR spectra and the spin-lattice relaxation times T{sub 1} of the {sup 87}Rb and {sup 133}Cs nuclei in the two crystals {yields} The variations in the symmetry of the octahedra of water molecules surrounding Rb{sup +} and Cs{sup +}.

Lim, Ae Ran, E-mail: aeranlim@hanmail.net [Department of Science Education, Jeonju University, Jeonju 560-759 (Korea, Republic of); Paik, Younkee [Solid State Analysis Team, Korea Basic Science Institute, Daegu 702-701 (Korea, Republic of); Lim, Kye-Young [Department of Energy and Electrical Engineering, Korea Polytechnic University, Siheung 429-793 (Korea, Republic of)

2011-06-15T23:59:59.000Z

296

Electrical conduction mechanism in La{sub 3}Ta{sub 0.5}Ga{sub 5.3}Al{sub 0.2}O{sub 14} single crystals  

SciTech Connect (OSTI)

The electrical conduction mechanism in La{sub 3}Ta{sub 0.5}Ga{sub 5.3}Al{sub 0.2}O{sub 14} (LTGA) single crystals was studied by nonstoichiometric defect formation during crystal growth. Since stoichiometric LTGA is not congruent, the single crystal grown from the stoichiometric melt was Ta-poor and Al-rich, where Al atoms were substituted not only in Ga sites but also in Ta sites. The population of the substitutional Al in Ta sites increased with increasing oxygen partial pressure during growth (growth-pO{sub 2}) in the range from 0.01 to 1?atm. Below 600?°C, substitutional Al atoms in Ta sites were ionized to yield holes, and thus the electrical conductivity of the LTGA crystal depended on temperature and the growth-pO{sub 2}. The dependence of the electrical conductivity on the growth-pO{sub 2} decreased as temperature increased. The temperature rise increases ionic conductivity, for which the dominant carriers are oxygen defects formed by the anion Frenkel reaction.

Yaokawa, Ritsuko, E-mail: e4777-1009@yahoo.co.jp; Aota, Katsumi [Citizen Holdings Co., Ltd., 840, Shimotomi, Tokorozawa, Saitama 359-8511 (Japan); Uda, Satoshi [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

2013-12-14T23:59:59.000Z

297

Quantum Critical Behavior in the Heavy Fermion Single Crystal Ce(Ni0.935Pd0.065)2Ge2  

SciTech Connect (OSTI)

We have performed magnetic susceptibility, specific heat, resistivity, and inelastic neutron scattering measurements on a single crystal of the heavy Fermion compound Ce(Ni{sub 0.935}Pd{sup 0.065}){sub 2}Ge{sub 2}, which is believed to be close to a quantum critical point (QCP) at T = 0. At lowest temperature (1.8--3.5 K), the magnetic susceptibility behaves as {chi}(T)-{chi} (0) {proportional_to} T{sup -1/6} with {chi} (0) = 0.032 x 10{sup -6} m{sup 3}/mole (0.0025 emu/mole). For T < 1 K, the specific heat can be fit to the formula {Delta} C/T = {gamma}{sub 0} - T{sup 1/2} with {gamma}{sub 0} of order 700 mJ/mole-K{sup 2}. The resistivity behaves as {rho} = {rho}{sub 0} + AT{sup 3/2} for temperatures below 2 K. This low temperature behavior for {gamma} (T) and {rho} (T) is in accord with the SCR theory of Moriya and Takimoto. The inelastic neutron scattering spectra show a broad peak near 1.5 meV that appears to be independent of Q; we interpret this as Kondo scattering with T{sub K} = 17 K. In addition, the scattering is enhanced near Q=(1/2, 1/2, 0) with maximum scattering at {Delta} E = 0.45 meV{sup -}; we interpret this as scattering from antiferromagnetic fluctuations near the antiferromagnetic QCP.

Wang, Cuihuan [ORNL; Lawrence, J M [University of California, Irvine; Christianson, Andrew D [ORNL; Chang, S [NIST Center for Neutron Research (NCRN), Gaithersburg, MD; Bauer, E D [Los Alamos National Laboratory (LANL); Gofryk, K [Los Alamos National Laboratory (LANL); Ronning, F [Los Alamos National Laboratory (LANL); Thompson, J D [Los Alamos National Laboratory (LANL); McClellan, K J [Los Alamos National Laboratory (LANL); Rodriguez-Rivera, J A [NCNR and University of Maryland; Lynn, J W [NIST Center for Neutron Research (NCRN), Gaithersburg, MD

2011-01-01T23:59:59.000Z

298

Upper critical fields and thermally-activated transport of Nd(0.7Fe0.3) FeAs single crystal  

SciTech Connect (OSTI)

We present measurements of the resistivity and the upper critical field H{sub c2} of Nd(O{sub 0.7}F{sub 0.3})FeAs single crystals in strong DC and pulsed magnetic fields up to 45 T and 60 T, respectively. We found that the field scale of H{sub c2} is comparable to {approx}100 T of high T{sub c} cuprates. H{sub c2}(T) parallel to the c-axis exhibits a pronounced upward curvature similar to what was extracted from earlier measurements on polycrystalline samples. Thus this behavior is indeed an intrinsic feature of oxypnictides, rather than manifestation of vortex lattice melting or granularity. The orientational dependence of H{sub c2} shows deviations from the one-band Ginzburg-Landau scaling. The mass anisotropy decreases as T decreases, from 9.2 at 44K to 5 at 34K. Spin dependent magnetoresistance and nonlinearities in the Hall coefficient suggest contribution to the conductivity from electron-electron interactions modified by disorder reminiscent that of diluted magnetic semiconductors. The Ohmic resistivity measured below T{sub c} but above the irreversibility field exhibits a clear Arrhenius thermally activated behavior over 4--5 decades. The activation energy has very different field dependencies for H{parallel}ab and H{perpendicular}ab. We discuss to what extent different pairing scenarios can manifest themselves in the observed behavior of H{sub c2}, using the two-band model of superconductivity. The results indicate the importance of paramagnetic effects on H{sub c2}(T), which may significantly reduce H{sub c2}(0) as compared to H{sub c2}(0) {approx}200--300 T based on extrapolations of H{sub c2}(T) near T{sub c} down to low temperatures.

Balakirev, Fedor F [Los Alamos National Laboratory; Jaroszynski, J [NHMFL, FSU; Hunte, F [NHMFL, FSU; Balicas, L [NHMFL, FSU; Jo, Youn - Jung [NHMFL, FSU; Raicevic, I [NHMFL, FSU; Gurevich, A [NHMFL, FSU; Larbalestier, D C [NHMFL, FSU; Fang, L [CHINA; Cheng, P [CHINA; Jia, Y [CHINA; Wen, H H [CHINA

2008-01-01T23:59:59.000Z

299

The structure of adsorbed sulfur and carbon on molybdenum and rhenium single crystal surfaces, and their influence on carbon monoxide and hydrocarbon chemisorption  

SciTech Connect (OSTI)

An ultra-high vacuum (10/sup -10/ Torr) study was performed on the chemisorption and structures of S and C adsorbates on Mo(100), Re(0001), and Re(1010) single crystal surfaces. Both S and C adsorb strongly on Mo(100), Re(0001), and Re(1010), with adsorption energies >70 kcal/mol for coverages less than saturation. S was proposed to adsorb in the highest symmetry sites on all surfaces except for theta/sub s/ > 0.75 on Mo(100), where studies suggest two different adsorption sites. C adsorbs in a ''carbidic'' or active phase on Mo(100), where it is also proposed to adsorb in the highest symmetry sites. However, C adsorbs in a ''graphitic'' or inactive phase on Re(0001) and Re(1010). CO chemisorption on the S and C overlayers was found to be blocked (except for C on Mo(100)), with S blocking adsorption more efficiently than C. Changes in adsorption energy were determined to be caused by local crowding of CO molecules by S or C, rather than a long-range electronic interaction. Unsaturated hydrocarbons decomposed completely on Mo(100), Re(0001), and Re(1010). Similar to the results for CO chemisorption, strong adsorption of unsaturated hydrocarbons (leading to decomposition) was blocked by pre-adsorbed S, allowing only physisorption to occur (adsorption energies < 11 kcal/mol). The effect of pre-adsorbed ''graphitic'' C on Re(0001) and Re(1010) on unsaturated hydrocarbon chemisorption was the same; strong adsorption (leading to decomposition) was blocked allowing only physisorption. However, Mo(100) with pre-adsorbed ''carbidic'' carbon blocks only decomposition while allowing strong reversible molecular chemisorption (12 to 23 kcal/mol). Differences in inhibition efficiency of S and C are proposed to be caused by differences in bond distances of the adsorbates to the surface. Greater distance from the metal surface causes more interaction with neighboring metal atoms. These differences also suggest explanations for catalytic hydrodesulfurization of thiophene.

Kelly, D.G.

1987-08-01T23:59:59.000Z

300

Spent-fuel special-studies progress report: probable mechanisms for oxidation and dissolution of single-crystal UO/sub 2/ surfaces  

SciTech Connect (OSTI)

Due to the complexity of the structural, microstructural and compositional characteristics of spent fuel, basic leaching and dissolution mechanisms were studied with UO/sub 2/ matrix material, specifically with single-crystal UO/sub 2/, to isolate individual contributory factors. The effects of oxidation and oxidation-dissolution were investigated in different oxidation conditions, such as in air, oxygenated solutions and deionized water containing H/sub 2/O/sub 2/. In addition, the effects of temperature on dissolution of UO/sub 2/ were studied in autoclaves at 75 and 150/sup 0/C. Also, oxidation and dissolution measurements were investigated via electrochemical methods to determine if those techniques could be applied to the characterization of leaching and dissolution of spent fuel in a hot cell. Finally, the effects of radiation were explored since the radiolysis of water may create a localized oxidizing condition at or near the spent fuel-solution interface, even in neutral or reducing conditions as commonly found in deep geological environments. The oxidation and oxidation-dissolution mechanisms for UO/sub 2/ are proposed as follows: The UO/sub 2/ surface is first oxidized in solution to form a UO/sub 2+x/ surface layer several angstroms thick. This oxidized surface has a high dissolution rate since the UO/sub 2+x/ reacts with the dissolved O/sub 2/, or H/sub 2/O/sub 2/, to form uranyl complex ions in a U(VI) state. As the uranyl ions exceed the solubility limits in solution, they become hydrolyzed to form solid deposits and suspended particles of UO/sub 3/ hydrates. The thickness and porosity of the deposited UO/sub 3/ hydrate surface-film is dependent on temperature, pH and deposition time. A long-term dissolution rate is then determined by the nature of the surface film, such as porosity, solubility and mechanical properties.

Wang, R.

1981-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


301

Anisotropic dynamics of water ultra-confined in macroscopically oriented channels of single-crystal beryl: A multi-frequency analysis  

SciTech Connect (OSTI)

The properties of fluids can be significantly altered by the geometry of their confining environments. While there has been significant work on the properties of such confined fluids, the properties of fluids under ultraconfinement, environments where, at least in one plane, the dimensions of the confining environment are similar to that of the confined molecule, have not been investigated. This paper investigates the dynamic properties of water in beryl (Be3Al2Si6O18), the structure of which contains approximately 5-A-diam channels parallel to the c axis. Three techniques, inelastic neutron scattering, quasielastic neutron scattering, and dielectric spectroscopy, have been used to quantify these properties over a dynamic range covering approximately 16 orders of magnitude. Because beryl can be obtained in large single crystals we were able to quantify directional variations, perpendicular and parallel to the channel directions, in the dynamics of the confined fluid. These are significantly anisotropic and, somewhat counterintuitively, show that vibrations parallel to the c-axis channels are significantly more hindered than those perpendicular to the channels. The effective potential for vibrations in the c direction is harder than the potential in directions perpendicular to it. There is evidence of single-file diffusion of water molecules along the channels at higher temperatures, but below 150 K this diffusion is strongly suppressed. No such suppression, however, has been observed in the channel-perpendicular direction. Inelastic neutron scattering spectra include an intramolecular stretching O-H peak at 465 meV. As this is nearly coincident with that known for free water molecules and approximately 30 meV higher than that in liquid water or ice, this suggests that there is no hydrogen bonding constraining vibrations between the channel water and the beryl structure. However, dielectric spectroscopic measurements at higher temperatures and lower frequencies yield an activation energy for the dipole reorientation of 16.4 0.14 kJ/mol, close to the energy required to break a hydrogen bond in bulk water. This may suggest the presence of some other form of bonding between the water molecules and the structure, but the resolution of the apparent contradiction between the inelastic neutron and dielectric spectroscopic results remains uncertain.

Anovitz, Lawrence {Larry} M [ORNL; Mamontov, Eugene [ORNL] [ORNL; Ishai, Paul ben [The Hebrew University of Jerusalem, Israel] [The Hebrew University of Jerusalem, Israel; Kolesnikov, Alexander I [ORNL] [ORNL

2013-01-01T23:59:59.000Z

302

OPTICAL AND PHYSICAL PROPERTIES OF CERAMIC CRYSTAL LASER MATERIALS.  

E-Print Network [OSTI]

??Historically ceramic crystal laser material has had disadvantages compared to single crystal laser material. However, progress has been made in the last decade and a… (more)

Simmons, Jed

2007-01-01T23:59:59.000Z

303

Tensile stress induced depolarization in [001]-poled transverse mode Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3} -(6-7)%PbTiO{sub 3} single crystals  

SciTech Connect (OSTI)

This paper investigates the effects of electrically induced and direct tensile stress on the deformation and dielectric properties of Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-(6-7)%PbTiO{sub 3} single crystals of [110]{sup L}x[001]{sup T} cut by using a unimorph sample and a four-point-bend (FPB) sample, respectively. The results show a dip in tip displacement for the unimorph sample at sufficiently high electric field parallel to the poling field direction and a sudden rise in capacitance for the FPB sample at sufficiently high tensile stress in the [110] crystal direction, respectively. These phenomena are attributed to the tensile stress induced rhombohedral-to-orthorhombic phase transition and associated depolarization events in the crystal. For the said crystal cut, the obtained tensile depoling stress is in the range of 15-20 MPa. The present work furthermore shows that the occurrence of tensile stress-induced depolarization is possible even when the direction of the applied electric field is parallel to the poling field direction, as in the unimorph sample examined.

Shukla, Rahul [Suman Mashruwala Advanced Microengineering Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 400076 (India); Department of Mechanical Engineering, National University of Singapore, Singapore 119260 (Singapore); Lim, Leong-Chew [Department of Mechanical Engineering, National University of Singapore, Singapore 119260 (Singapore); Microfine Materials Technologies Pte. Ltd., 10 Bukit Batok Crescent, 06-02 The Spire, Singapore 658079 (Singapore); Gandhi, Prasanna [Suman Mashruwala Advanced Microengineering Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 400076 (India)

2011-04-01T23:59:59.000Z

304

Effect of a high electric field on the conductivity of MnGa{sub 2}S{sub 4}, MnIn{sub 2}S{sub 4}, and MnGaInS{sub 4} single crystals  

SciTech Connect (OSTI)

The results of studying the effect of a high electric field on the conductivity of MnGa{sub 2}S{sub 4}, MnIn{sub 2}S{sub 4}, and MnGaInS{sub 4} single crystals are reported. The activation energy is determined in high and low electric fields. It is established that the decrease in the activation energy with increasing the external voltage is associated with decreasing the depth of the potential well, in which the electron is located.

Niftiev, N. N. [Azerbaijan State Pedagogical University (Azerbaijan); Tagiev, O. B. [National Academy of Sciences of Azerbaijan, Institute of Physics (Azerbaijan)

2009-09-15T23:59:59.000Z

305

E-Print Network 3.0 - aided lateral crystallization Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

(FOM) Collection: Mathematics ; Materials Science 7 Photon tunnelling microscopy of polyethylene single crystals Summary: Photon tunnelling microscopy of polyethylene single...

306

Technology Development for High-Efficiency Solar Cells and Modules Using Thin (<80 um) Single-Crystal Silicon Wafers Produced by Epitaxy: June 11, 2011 - April 30, 2013  

SciTech Connect (OSTI)

Final technical progress report of Crystal Solar subcontract NEU-31-40054-01. The objective of this 18-month program was to demonstrate the viability of high-efficiency thin (less than 80 um) monocrystalline silicon (Si) solar cells and modules with a low-cost epitaxial growth process.

Ravi, T. S.

2013-05-01T23:59:59.000Z

307

Single crystal flow reactor for studying reactivities on metal oxide model catalysts at atmospheric pressure to bridge the pressure gap to the adsorption properties determined under UHV conditions  

Science Journals Connector (OSTI)

A flow reactor for the investigation of heterogeneous catalytic reactions on single crystalline metal oxide model catalysts has been designed. It is located in a high pressure cell attached to an UHV analysis cha...

C. Kuhrs; M. Swoboda; W. Weiss

2001-01-01T23:59:59.000Z

308

Structural and proton-dynamical effects in a proton-irradiated KH{sub 2}PO{sub 4} single crystal  

SciTech Connect (OSTI)

A KH{sub 2}PO{sub 4} (KDP) crystal, irradiated by a 1 MeV hydrogen ion beam to a dose of 10{sup 15} ions/cm{sup 2}, was studied by means of x-ray diffraction (XRD), {sup 1}H nuclear magnetic resonance (NMR), and dielectric constant measurements. The XRD pattern for the a-cut KDP crystal revealed a decrease in the lattice constant along the a axis after the proton irradiation. According to the {sup 1}H NMR spin-lattice relaxation rate measurements, the proton irradiation gave rise to reduction in the activation energy in the paraelectric phase, from 0.42 to 0.28 eV, in agreement with the temperature dependent second moment measurements indicating the proton motion is more activated after the proton irradiation. Besides, analysis of the temperature-dependent dielectric constants using a mean-field approximation revealed a change in the hydrogen bond induced by the proton irradiation.

Kim, S. H.; Oh, B. H.; Lee, K. W.; Lee, Cheol Eui; Hong, K. S. [Department of Physics and Institute for Nano Science, Korea University, Seoul 136-713 (Korea, Republic of); Korea Basic Science Institute, Daejeon 305-333 (Korea, Republic of)

2006-04-01T23:59:59.000Z

309

Effect of {gamma}-ray radiation on electrical properties of heat-treated Tb{sub x}Sn{sub 1-x}Se single crystals  

SciTech Connect (OSTI)

The effect of {gamma}-ray radiation on the electrical properties of heat-treated Tb{sub 0.01}Sn{sub 0.99}Se (sample 1) and Tb{sub 0.05}Sn{sub 0.95}Se (sample 2) samples is studied. It is found that, as a result of irradiation with {gamma}-ray 1.25-MeV photons, the charge-carrier concentration decreases in the temperature range T = 77-200 K by 17 and 6.3% for samples 1 and 2, respectively. It is assumed that, in the course of irradiation with {gamma}-ray photons, terbium impurity atoms are located between sites of the crystal lattice; in addition, Frenkel defects are formed.

Huseynov, J. I., E-mail: cih_58@mail.ru; Jafarov, T. A. [Azerbaijan State Pedagogical University (Azerbaijan)

2012-04-15T23:59:59.000Z

310

Synthesis and characterization of alkali-metal titanium alkoxide compounds MTi(O-i-Pr) sub 5 (M = Li, Na, K): Single-crystal x-ray diffraction structure of (LiTi(O-i-Pr) sub 5 ) sub 2  

SciTech Connect (OSTI)

The series (MTi(O-iPr){sub 5}), M = Li, Na, or K, has been prepared by the reaction of MO-i-Pr with Ti(O-i-Pr){sub 4}. A single-crystal x-ray diffraction study revealed that (LiTi(O-i-Pr){sub 5}) crystallizes from toluene at {minus}30{degree}C in the monoclinic space group P2{sub 1}/n, with unit cell dimensions a = 11.440 (8) {angstrom}, b = 16.396 (13) {angstrom}, c = 11.838 (8) {angstrom}, {beta} = 92.59 (5){degree}, and Z = 4, as a dimer containing two approximately trigonal-bipyramidal titanium centers linked by lithium bridges. In benzene solution, all three compounds are dimeric, as revealed by cryoscopic molecular weight determination, and all three undergo an alkoxide ligand exchange process that is rapid on the {sup 1}H NMR time scale at room temperature. The positions of {nu}(M-O) are assigned based on the low-energy shifts observed upon deuteriation of the isopropoxide ligands. 23 refs., 3 figs., 3 tabs.

Hampden-Smith, M.J.; Williams, D.S. (Univ. of New Mexico, Albuquerque (USA)); Rheingold, A.L. (Univ. of Delaware, Newark (USA))

1990-10-03T23:59:59.000Z

311

Manifestation of light and heavy electrons in the galvanomagnetic characteristics of Te-doped n-Bi{sub 0.88}Sb{sub 0.12} single crystals  

SciTech Connect (OSTI)

The components of resistivity ({rho}{sub ij}), Hall coefficient (R{sub ijk}), and magnetoresistance ({rho}{sub ij,kl}) of n-Bi{sub 0.88}Sb{sub 0.12} single crystals doped with tellurium to 0.01, 0.1, and 0.2 at % have been measured in the temperature range of 77-300 K. It is concluded that light and heavy electrons are involved in transport processes. The energy spacing between the bands of light and heavy electrons is found to be 40 meV, and the ratios of the effective masses and electron mobilities are estimated as m{sub 2}*/m{sub l}* = 3 and b Almost-Equal-To 0.16, respectively.

Tairov, B. A., E-mail: btairov@physics.ab.az; Ibragimova, O. I., E-mail: ofeliya_i@physics.ab.az; Rahimov, A. H. [National Academy of Sciences of Azerbaijan, Institute of Physics (Azerbaijan); Brazis, R., E-mail: brazis@pfi.lt [Semiconductor Physics Institute (Lithuania)

2011-02-15T23:59:59.000Z

312

Electronic structure and fundamental absorption edges of KPb2Br5, K0.5Rb0.5Pb2Br5, and RbPb2Br5 single crystals  

Science Journals Connector (OSTI)

X-ray photoelectron core-level and valence-band spectra for pristine and Ar+-ion irradiated (001) surfaces of KPb2Br5, K0.5Rb0.5Pb2Br5, and RbPb2Br5 single crystals grown by the Bridgman method have been measured and fundamental absorption edges of the ternary bromides have been recorded in the polarized light at 300 K and 80 K. The present X-ray photoelectron spectroscopy (XPS) results reveal high chemical stability of (001) surfaces of KxRb1?xPb2Br5 (x=0, 0.5, and 1.0) single crystals. Substitution of potassium for rubidium in KxRb1?xPb2Br5 does not cause any changes of binding energy values and shapes of the XPS constituent element core-level spectra. Measurements of the fundamental absorption edges indicate that band gap energy, Eg, increases by about 0.14 and 0.19 eV when temperature decreases from 300 K to 80 K in \\{KPb2Br5\\} and RbPb2Br5, respectively. Furthermore, there is no dependence of the Eg value for \\{KPb2Br5\\} upon the light polarization, whilst the band gap energy value for RbPb2Br5 is bigger by 0.03–0.05 eV in the case of E?c compared to those in the cases of E?a and E?b.

A.Yu. Tarasova; L.I. Isaenko; V.G. Kesler; V.M. Pashkov; A.P. Yelisseyev; N.M. Denysyuk; O.Yu. Khyzhun

2012-01-01T23:59:59.000Z

313

Two?dimensional nuclear magnetic resonance studies on a single crystal of l?alanine. Separation of the local dipolar fields; and 2D exchange spectroscopy of the 1 4N relaxation processes  

Science Journals Connector (OSTI)

Two types of 2DNMR techniques namely separated local field 2DNMR (SLF 2DNMR) and 2D exchange NMR spectroscopy were applied to a single crystal of l?alanine at room temperature. In the SLF 2DNMR experiments we found that the 1 3C–1H dipolar field at the C?carbon nucleus could be separated not only from the chemical shift interaction but also from the 1 3C?–1 4N dipolar field. The angular variation of the 1 3C?–1H dipolar splitting was measured when the static magnetic field was rotated about three orthogonal axes (a b and c axes). The 1 3C??1H dipolar coupling tensor was determined and the C?–H bond length was evaluated to be 1.073 Å. In the 2D exchange NMR experiment for C?carbon nucleus the off?diagonal cross peaks due to the single quantum and the double quantum transitions for the spin?lattice relaxation processes of the adjacent 1 4N nucleus were observed. The single quantum transition rate constant was evaluated to be 0.8 s? 1 and the double quantum transition rate constant was estimated to be much smaller. Inspection of the experimental results of the 2D exchange NMR together with the theory indicates that (1) the double quantum cross peaks which appeared when a long mixing time (? m =1.0 s) was used is brought about by two consecutive single quantum processes and (2) the main spin?lattice relaxation process of the NH+ 3 nitrogen nucleus is the fluctuation of 1 4N–1H dipolar interaction rather than the fluctuation of 1 4N quadrupole interaction.

A. Naito; P. B. Barker; C. A. McDowell

1984-01-01T23:59:59.000Z

314

Hypersonic and dielectric anomalies of ,,Pb,,Zn1/3Nb2/3...O3...0.905,,PbTiO3...0.095 single crystal Chi-Shun Tu, F.-C. Chao, C.-H. Yeh, and C.-L. Tsai  

E-Print Network [OSTI]

Hypersonic and dielectric anomalies of ,,Pb,,Zn1/3Nb2/3...O3...0.905,,PbTiO3...0.095 single crystal scattering and dielectric permittivity on PZN-9.5%PT to look for both hypersonic and dielectric anomalies

315

Large magnetic penetration depth and thermal fluctuations in a superconducting Ca10(Pt3As8)[(Fe1 xPtx)2As2]5 (x = 0.097) single crystal  

SciTech Connect (OSTI)

We have measured the temperature dependence of the absolute value of the magnetic penetration depth {lambda}(T) in a Ca{sub 10}(Pt{sub 3}As{sub 8})[(Fe{sub 1-x}Pt{sub x}){sub 2}As{sub 2}]{sub 5} (x = 0.097) single crystal using a low-temperature magnetic force microscope (MFM). We obtain {lambda}{sub ab}(0) {approx} 1000 nm via extrapolating the data to T = 0. This large {lambda} and pronounced anisotropy in this system are responsible for large thermal fluctuations and the presence of a liquid vortex phase in this low-temperature superconductor with a critical temperature of 11 K, consistent with the interpretation of the electrical transport data. The superconducting parameters obtained from {lambda} and coherence length {zeta} place this compound in the extreme type II regime. Meissner responses (via MFM) at different locations across the sample are similar to each other, indicating good homogeneity of the superconducting state on a submicron scale.

Kim J.; Nazaretski E.; Ronning, F.; Haberkorn, N.; Civale, L.; Ni, N.; Cava, R.J.; Thompson, J.D.; Movshovich, R.

2012-05-18T23:59:59.000Z

316

Temperature dependence of structural parameters in oxide-ion-conducting Nd{sub 9.33}(SiO{sub 4}){sub 6}O{sub 2}: single crystal X-ray studies from 295 to 900K  

SciTech Connect (OSTI)

Crystallographic space group, structural parameters and their thermal changes in oxide-ion-conducting Nd{sub 9.33}(SiO{sub 4}){sub 6}O{sub 2} were investigated using high-temperature single-crystal X-ray diffraction experiments in the temperature range of 295=

Okudera, Hiroki [Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, DE-70569 Stuttgart (Germany)]. E-mail: h.okudera@fkf.mpg.de; Yoshiasa, Akira [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043 (Japan); Masubuchi, Yuuji [Material Science and Engineering, Graduate School of Engineering, Hokkaido University, N13, W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Higuchi, Mikio [Material Science and Engineering, Graduate School of Engineering, Hokkaido University, N13, W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Kikkawa, Shinichi [Material Science and Engineering, Graduate School of Engineering, Hokkaido University, N13, W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)

2004-12-01T23:59:59.000Z

317

In-situ Studies of the Reactions of Bifunctional and Heterocyclic Molecules over Noble Metal Single Crystal and Nanoparticle Catalysts Studied with Kinetics and Sum-Frequency Generation Vibrational Spectroscopy  

SciTech Connect (OSTI)

Sum frequency generation surface vibrational spectroscopy (SFG-VS) in combination with gas chromatography (GC) was used in-situ to monitor surface bound reaction intermediates and reaction selectivities for the hydrogenation reactions of pyrrole, furan, pyridine, acrolein, crotonaldehyde, and prenal over Pt(111), Pt(100), Rh(111), and platinum nanoparticles under Torr reactant pressures and temperatures of 300K to 450K. The focus of this work is the correlation between the SFG-VS observed surface bound reaction intermediates and adsorption modes with the reaction selectivity, and how this is affected by catalyst structure and temperature. Pyrrole hydrogenation was investigated over Pt(111) and Rh(111) single crystals at Torr pressures. It was found that pyrrole adsorbs to Pt(111) perpendicularly by cleaving the N-H bond and binding through the nitrogen. However, over Rh(111) pyrrole adsorbs in a tilted geometry binding through the {pi}-aromatic orbitals. A surface-bound pyrroline reaction intermediate was detected over both surfaces with SFG-VS. It was found that the ring-cracking product butylamine is a reaction poison over both surfaces studied. Furan hydrogenation was studied over Pt(111), Pt(100), 10 nm cubic platinum nanoparticles and 1 nm platinum nanoparticles. The product distribution was observed to be highly structure sensitive and the acquired SFG-VS spectra reflected this sensitivity. Pt(100) exhibited more ring-cracking to form butanol than Pt(111), while the nanoparticles yielded higher selectivities for the partially saturated ring dihydrofuran. Pyridine hydrogenation was investigated over Pt(111) and Pt(100). The {alpha}-pyridyl surface adsorption mode was observed with SFG-VS over both surfaces. 1,4-dihydropyridine was seen as a surface intermediate over Pt(100) but not Pt(111). Upon heating the surfaces to 350K, the adsorbed pyridine changes to a flat-lying adsorption mode. No evidence was found for the pyridinium cation. The hydrogenation of the {alpha},{beta}-unsaturated aldehydes acrolein, crotonaldehyde, and prenal were investigated over Pt(111) and Pt(100). The selectivity for the hydrogenation of the C=C bond was found to depend on the number of methyl groups added to the bond. The adsorption modes of the three aldehydes were determined. The hydrogenation of crotonaldehyde was found to be nearly structure insensitive as the TOF and selectivity were very close to the same over Pt(111) and Pt(100). SFG-VS indicated identical surface intermediates over the two crystal faces during crotonaldehyde hydrogenation.

Kliewer, Christopher J.

2009-06-30T23:59:59.000Z

318

Photo-effects in iodine single crystals  

E-Print Network [OSTI]

Effects 29 29 29 34 34 4D CHAPTER V. DISCUSSIGN A. Dark EMF Values B. photo EMP Spectral Response D. Tenperature Dependence 42 42 44 45 APPENDIX A . Tabulation of Driginal Experlnsntal Data B. Changes in Dark end I hoto EMP... with Tenperature 50 58 54 REFKRENCES LIST OP TABLES Table Effects of various gaseous amhients on dark and photo emf values Page 31 II Effects of cooling on dark and photo emf values 33 vi LIST OF PIGVRES Figure Possible photo-transitions in sn...

Rieves, John Michael

2012-06-07T23:59:59.000Z

319

High-Pressure Single-Crystal Techniques  

Science Journals Connector (OSTI)

...systems such as water, methanol, formic acid, oxygen, carbon dioxide and methane...cryostat or a furnace. It is still worth mentioning some older reviews covering...However, due to the high world-market prize of large diamonds and the fact...

Ronald Miletich; David R. Allan; Werner F. Kuhs

320

Molecular Transformations on Single Crystal Metal Surfaces  

Science Journals Connector (OSTI)

...ACIDITIES OF GAS-PHASE ACIDS FOR DISPLACEMENT OF SURFACE...THERMAL-DESORPTION STUDY OF FORMIC-ACID DECOMPOSITION ON A CLEAN...In forward-looking markets the exchange rate will...spectrum (TPRS) for formic acid reaction with Cu(110...

R. J. MADIX

1986-09-12T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Optical measurements of methyl group tunneling in molecular crystals: Temperature dependence of the nuclear spin conversion rate  

E-Print Network [OSTI]

) The tunneling methyl groups in dimethyl-s-tetrazine (DMST) doped single crystals of durene were investigated

322

Magnetic-resonance and thermophysical studies of the magnetic phase diagram for a GdFe{sub 2.1}Ga{sub 0.9}(BO{sub 3}){sub 4} single crystal  

SciTech Connect (OSTI)

The antiferromagnetic resonance, heat capacity, magnetic properties, and magnetic phase diagram of a GdFe{sub 3}(BO{sub 3}){sub 4} crystal in which some of the iron ions were substituted by diamagnetic gallium ions have been investigated. It has been found that the Neel temperature upon diamagnetic substitution decreased to 17 K compared to 38 K in the unsubstituted crystal. The effective exchange and anisotropy fields for GdFe{sub 2.1}Ga{sub 0.9}(BO{sub 3}){sub 4} have been estimated from the field dependences of magnetization and resonance measurements. The magnetic phase diagram of the crystal has been constructed from magnetic and resonance measurements. In GdFe{sub 2.1}Ga{sub 0.9}(BO{sub 3}){sub 4}, there is no spontaneous reorientation and, in the absence of a magnetic field, the crystal remains an easy-axis one in the entire domain of magnetic ordering. The critical field of the reorientation transition to an induced easy-plane state in a magnetic field along the trigonal axis has been found to increase compared to that in the unsubstituted crystal.

Pankrats, A. I.; Petrakovskii, G. A.; Tugarinov, V. I., E-mail: vit@iph.krasn.ru; Kartashev, A. V.; Temerov, V. L. [Russian Academy of Science, Siberian Branch, Kirensky Institute of Physics (Russian Federation)

2011-09-15T23:59:59.000Z

323

/ http://www.sciencemag.org/content/early/recent / 3 April 2014 / Page 1 / 10.1126/science.1252268 The availability of high-quality, large, single-crystal Si wafers is funda-  

E-Print Network [OSTI]

separated by defective grain boundaries that degrade their electri- cal and mechanical properties (8, 9 and coalesce into a uniform sin- gle-crystal layer without grain bounda- ry defects, even if the nucleation and the relatively high car- bon solubility hamper the direct growth of high-quality monolayer graphene on Si (16

Napp, Nils

324

High energy resolution, high angular acceptance crystal monochromator  

DOE Patents [OSTI]

A 4-bounce dispersive crystal monochromator reduces the bandpass of synchrotron radiation to a 10-50 meV range without sacrificing angular acceptance. The monochromator includes the combination of an asymmetrical channel-cut single crystal of lower order reflection and a symmetrical channel-cut single crystal of higher order reflection in a nested geometric configuration. In the disclosed embodiment, a highly asymmetrically cut (.alpha.=20) outer silicon crystal (4 2 2) with low order reflection is combined with a symmetrically cut inner silicon crystal (10 6 4) with high order reflection to condition a hard x-ray component (5-30 keV) of synchrotron radiation down to the .mu.eV-neV level. Each of the crystals is coupled to the combination of a positioning inchworm and angle encoder via a respective rotation stage for accurate relative positioning of the crystals and precise energy tuning of the monochromator.

Alp, Ercan E. (Bolingbrook, IL); Mooney, Timothy M. (Westmont, IL); Toellner, Thomas (Green Bay, WI)

1996-06-04T23:59:59.000Z

325

Monochromator Crystal Glitch Library  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

SSRL's Monochromator Crystal Glitch Library allows users to view glitch spectra online, list specific crystal orientations, and download PDF files of the glitch spectra. (Specialized Interface)

326

Crystal shape effect on nuclear orientation thermometry at ultra-low temperatures  

Science Journals Connector (OSTI)

Absolute temperature measurement (T mK region) from anisotropy of gamma radiations emitted from oriented60Co nuclei in a single crystal of hcp cobalt is found to depend on the shape of the crystal. This dep...

T S Radhakrishnan; Girish Chandra

1974-04-01T23:59:59.000Z

327

Absence of Wigner crystallization in graphene  

Science Journals Connector (OSTI)

Graphene, a single sheet of graphite, has attracted tremendous attention due to recent experiments which demonstrate that carriers in it are described by massless fermions with linear dispersion. In this Brief Report, we consider the possibility of Wigner crystallization in graphene in the absence of an external magnetic field. We show that the ratio of potential and kinetic energy is independent of the carrier density, the tuning parameter that usually drives Wigner crystallization, and find that for given material parameters (dielectric constant and Fermi velocity), Wigner crystallization is not possible. We comment on how these results change in the presence of a strong external magnetic field.

Hari P. Dahal; Yogesh N. Joglekar; Kevin S. Bedell; Alexander V. Balatsky

2006-12-29T23:59:59.000Z

328

Temperature-induced and electric-field-induced phase transitions in rhombohedral Pb(In1/2Nb1/2)O3?Pb(Mg1/3Nb2/3)O3?PbTiO3 ternary single crystals  

Science Journals Connector (OSTI)

Temperature and electric field effects on rhombohedral (R) ternary Pb(In1/2Nb1/2)O3?Pb(Mg1/3Nb2/3)O3?PbTiO3 (PIN-PMN-PT) ferroelectric single crystals were comprehensively studied by x-ray diffraction. We have focused on how the individual phase transitions as well as the phase transition sequences depend on thermal and electrical history. Electric field-temperature phase diagrams have been constructed under [001] field-cooling and field-heating conditions. As happens to the R phase of binary PMN-PT crystals [H. Cao, J. F. Li, D. Viehland, and G. Y. Xu, Phys. Rev. B 73, 184110 (2006)], the R phase of the zero-field-cooled (ZFC) state is replaced by a monoclinic A (M) phase in the field-cooled (FC) diagram. In particular, reciprocal-space mesh scans demonstrated that the M phase was stable for crystals poled along the [001] crystallographic direction rather than the initial R phase of the ZFC state. Furthermore, an E-field-induced phase transformational sequence of R?M? tetragonal (T) was observed at constant temperature, revealing a gradual increase in the c lattice parameter. These findings demonstrate that the ternary PIN-PMN-PT crystals exhibit common phase transition features with binary PMN-PT and Pb(Zn1/3Nb2/3)O3?PbTiO3 (PZN-PT) ones for compositions in the low PT side of the morphotropic phase boundary.

Yaojin Wang (???); Zhiguang Wang; Wenwei Ge; Chengtao Luo; Jiefang Li; D. Viehland; Jianwei Chen; Haosu Luo

2014-10-23T23:59:59.000Z

329

Crystallography of Quasiperiodic Crystals  

Science Journals Connector (OSTI)

A unified description is given of modulated crystals and quasicrystals based on higher-dimensional crystallography.

Yamamoto, A.

1996-07-01T23:59:59.000Z

330

Crystal structure of guggulsterone Z  

SciTech Connect (OSTI)

The crystal structure of the title compound (4,17(20)-trans-pregnadiene-3,16-dione, C{sub 21}H{sub 28}O{sub 2}) has been determined by direct methods using single-crystal X-ray diffraction data. The compound crystallizes into the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1} with the unit cell parameters a = 7.908(2) A, b = 13.611(3) A, c = 16.309(4) A, and Z = 4. The structure has been refined to R = 0.058 for 3667 observed reflections. The bond distances and angles are in good agreement with guggulsterone E and other related steroid molecules. Ring A exists in the distorted sofa conformation, while rings B and C adopt the distorted chair conformation. Five-membered ring D is intermediate between the half-chair and envelope conformations. The A/B ring junction is quasi-trans, while ring systems B/C and C/D are trans fused about the C(8)-C(9) and C(13)-C(14) bonds, respectively. The steroid nucleus has a small twist, as shown by the C(19)-C(10)...C(13)-C(18) pseudo-torsion angle of 7.2{sup o}. The crystal structure is stabilized by intra-and intermolecular C-H...O hydrogen bonds.

Gupta, V. K., E-mail: vivek_gupta2k2@hotmail.com; Bandhoria, P. [University of Jammu, Post Graduate Department of Physics (India); Gupta, B. D.; Gupta, K. K. [Regional Research Laboratory (India)

2006-03-15T23:59:59.000Z

331

CRYSTALLIZATION IN MULTICOMPONENT GLASSES  

SciTech Connect (OSTI)

In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

KRUGER AA; HRMA PR

2009-10-08T23:59:59.000Z

332

Chapter 6 - Electronic Properties of Selected Crystals  

Science Journals Connector (OSTI)

Abstract In this chapter we give a brief survey of the electronic structure of some crystals of particular interest from a fundamental or technological point of view; the focus is not on the properties of single specific crystals, but rather on the trends in similar compounds. We begin with the description of rare-gas solids, which are large gap insulators formed by weakly interacting closed-shell neutral atoms. We then describe ionic crystals, constituted by strongly interacting closed-shell ions. In the discussion of crystals made up by open-shell units, we consider typical examples of covalent semiconductors and of the metallic bond. We also describe some electronic features of carbon allotropes, with particular attention to Dirac points in the band structure of graphene.

Giuseppe Grosso; Giuseppe Pastori Parravicini

2014-01-01T23:59:59.000Z

333

Phasing tiny crystals  

Science Journals Connector (OSTI)

For tiny crystals, their diffraction intensities at and between the Bragg peaks become measurable due to the limited number of the unit cells, which can in principle be used to directly phase the crystal structures.

Miao, J.

2013-12-31T23:59:59.000Z

334

Growing Giant Crystals  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

kids Growing Giant Crystals A new process similar to making rock candy was developed at NIF to rapidly grow very large crystals that are about 2 cubic feet in size and weigh up to...

335

Automation in biological crystallization  

Science Journals Connector (OSTI)

Automation is the response to overcoming the crystallization bottleneck in biological crystallography. This review provides a summary of the current methods and technologies applied in automated platforms for the setup of initial and follow-up crystallization experiments.

Shaw Stewart, P.

2014-05-28T23:59:59.000Z

336

HANFORD MEDIUM-LOW CURIE WASTE PRETREATMENT ALTERNATIVES PROJECT FRACTIONAL CRYSTALLIZATION PILOT SCALE TESTING FINAL REPORT  

SciTech Connect (OSTI)

The Fractional Crystallization Pilot Plant was designed and constructed to demonstrate that fractional crystallization is a viable way to separate the high-level and low-activity radioactive waste streams from retrieved Hanford single-shell tank saltcake. The focus of this report is to review the design, construction, and testing details of the fractional crystallization pilot plant not previously disseminated.

HERTING DL

2008-09-16T23:59:59.000Z

337

CRYSTAL Simulation Code and New Coherent Effects in Bent Crystal at the LHC  

E-Print Network [OSTI]

The LHC crystal-based collimation system is mainly addressed. A CRYSTAL simulation code for particle tracking in crystals is introduced. Its essence consists in both adequate and fast sampling of proton trajectories in crystals which is crucial for both correct description of experiments and quantitative prediction of new effects. The H8 single-pass experiment at the CERN SPS as well as 7 TeV proton deflection by a bent crystal at the LHC are simulated. We predict the existence of dechanneling peaks corresponding to the planar channeling oscillations as well as describe the possibility of their observation at high energies, specifically in the LHC crystal-assisted collimation experiment planned on 2015. An effect of excess over the amorphous level of ionization losses in the channeling mode was also found for the LHC energy. In addition, the LHC crystal-based collimation system is simulated as well as its possible improved layouts with application of a crystal with the cut and multiple volume reflection in on...

Sytov, Alexei I

2014-01-01T23:59:59.000Z

338

Method for the preparation of photochromic insulating crystals  

DOE Patents [OSTI]

A method for preparing reversible-photochromic magnesium oxide (MgO) crystals is disclosed. Single crystals of MgO doped with both lithium (Li) and nickel (Ni) are grown by a conventional arc fusion method. The as-grown crystals are characterized by an amber coloration. The crystals lose the amber coloration and become photochromic when they are thermochemically reduced by heating at temperatures greater then 1000/sup 0/K in a hydrogen atmosphere. Alternate irradiation with uv and visible light result in rejuvenation and bleaching of the amber coloration, respectively.

Abraham, M.M.; Boldu, J.L.; Chen, Y.; Orera, V.M.

1984-09-28T23:59:59.000Z

339

JOURNAL DE PHYSIQUE Colloque C5, suppliment au no 5, Tome 40, Mai 1979, page C5-38 Magnetoresistance and anomalous Hall effect of magnesium singIe crystals  

E-Print Network [OSTI]

-38 Magnetoresistance and anomalous Hall effect of magnesium singIe crystals with heavy rare earth impurities J. Bijvoet splitting, the magnetization of rare earth ions in magnesium single crystals is anisotropic at low and cannot be explained by crystal field splitting of the 4f levels. Single crystals of magnesium with small

Paris-Sud XI, Université de

340

Crystal Fields in Dilute Rare-Earth Metals Obtained from Magnetization Measurements on Dilute Rare-Earth Alloys  

Science Journals Connector (OSTI)

Crystal field parameters of Tb, Dy, and Er in Sc, Y, and Lu are summarized. These parameters are obtained from magnetization measurements on dilute single crystals, and successfully checked by a number of different methods. The crystal field parameters vary unpredictably with the rare-earth solute. B40, B60, and B66 are similar in Y and Lu. Crystal field parameters for the pure metals Tb, Dy, and Er are estimated from the crystal fields in Y and Lu.

P. Touborg and J. Høg

1974-09-23T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

A synchroton single crystal X-ray structure determination of (NH4)3Mo4P3O16: A microporous molybdenum phosphate with Mo4O6+4 cubes  

Science Journals Connector (OSTI)

Reaction of MoO3, Mo, (NH4)2HPO4, H3PO4, and H2O in a mole ratio of 1.4:1:3.6:6:120 at 360°C for 16 hr gives a nearly quantitative yield of black cubes of (NH4)3Mo4P3O16 (1). The structure of (1) was solved from data collected on a 30 × 30 × 30 ?m3 crystal at the National Synchrotron Light Source at Brookhaven National Laboratory. The compound is cubic, space group P43m, with a = 7.736(2) Å, and was refined to residuals of R(Rw) = 0.035(0.049). Phosphate (1) is isotypic with Cs3Mo4P3O16 and is related to the iron arsenate mineral pharmacosiderite. Unlike the Cs+ compound, (1) can be rendered microporous by thermal removal of the NH+4 cations to give ammonia with the charge compensating proton remaining behind in the lattice. Water absorption isotherms show the reversible uptake of 5.6 wt% water, which corresponds to over 15 vol% void space in (1) after the NH3 removal. The framework consists of Mo4O6+4 cubes, with six Mo?Mo contacts of 2.570(4) Å, joined together together by (PO4)62 along ?100? to form a 3-D network composed of tetramers of triply edge-sharing Mo-centered octahedra and phosphate groups alternating along all ?100? directions. The windows and cavities in (1) are large enough that the NH+4 cations occupy several different positions in the unit cell.

H.E. King Jr.; Linda A. Mundi; Karl G. Strohmaier; Robert C. Haushalter

1991-01-01T23:59:59.000Z

342

Metamaterial model of a time crystal  

E-Print Network [OSTI]

Propagation of monochromatic extraordinary light in a hyperbolic metamaterial is identical to propagation of massive particles in a three dimensional effective Minkowski spacetime, in which the role of a timelike variable is played by one of the spatial coordinates. We demonstrate that this analogy may be used to build a metamaterial model of a time crystal, which has been recently suggested by Wilczek and Shapere. It is interesting to note that the effective single-particle energy spectrum in such a model does not contain a static ground state, thus providing a loophole in the proof of time crystal non-existence by P. Bruno.

Smolyaninov, Igor I

2015-01-01T23:59:59.000Z

343

Phononic crystal devices  

DOE Patents [OSTI]

Phononic crystals that have the ability to modify and control the thermal black body phonon distribution and the phonon component of heat transport in a solid. In particular, the thermal conductivity and heat capacity can be modified by altering the phonon density of states in a phononic crystal. The present invention is directed to phononic crystal devices and materials such as radio frequency (RF) tags powered from ambient heat, dielectrics with extremely low thermal conductivity, thermoelectric materials with a higher ratio of electrical-to-thermal conductivity, materials with phononically engineered heat capacity, phononic crystal waveguides that enable accelerated cooling, and a variety of low temperature application devices.

El-Kady, Ihab F. (Albuquerque, NM); Olsson, Roy H. (Albuquerque, NM)

2012-01-10T23:59:59.000Z

344

Channeling through Bent Crystals  

SciTech Connect (OSTI)

Bent crystals have demonstrated potential for use in beam collimation. A process called channeling is when accelerated particle beams are trapped by the nuclear potentials in the atomic planes within a crystal lattice. If the crystal is bent then the particles can follow the bending angle of the crystal. There are several different effects that are observed when particles travel through a bent crystal including dechanneling, volume capture, volume reflection and channeling. With a crystal placed at the edge of a particle beam, part of the fringe of the beam can be deflected away towards a detector or beam dump, thus helping collimate the beam. There is currently FORTRAN code by Igor Yazynin that has been used to model the passage of particles through a bent crystal. Using this code, the effects mentioned were explored for beam energy that would be seen at the Facility for Advanced Accelerator Experimental Tests (FACET) at a range of crystal orientations with respect to the incoming beam. After propagating 5 meters in vacuum space past the crystal the channeled particles were observed to separate from most of the beam with some noise due to dechanneled particles. Progressively smaller bending radii, with corresponding shorter crystal lengths, were compared and it was seen that multiple scattering decreases with the length of the crystal therefore allowing for cleaner detection of the channeled particles. The input beam was then modified and only a portion of the beam sent through the crystal. With the majority of the beam not affected by the crystal, most particles were not deflected and after propagation the channeled particles were seen to be deflected approximately 5mm. After a portion of the beam travels through the crystal, the entire beam was then sent through a quadrupole magnet, which increased the separation of the channeled particles from the remainder of the beam to a distance of around 20mm. A different code, which was developed at SLAC, was used to create an angular profile plot which was compared to what was produced by Yazynin's code for a beam with no multiple scattering. The results were comparable, with volume reflection and channeling effects observed and the range of crystal orientations at which volume reflection is seen was about 1 mrad in both simulations.

Mack, Stephanie; /Ottawa U. /SLAC

2012-09-07T23:59:59.000Z

345

THE CRYSTAL CLOCK  

Science Journals Connector (OSTI)

...crystal are connected between the grid and filament of the oscillator tube, a grid leak being connected across the crystal to provide the proper grid bias. A parallel resonant circuit...cycles, and a mercury damped flywheel used to reduce hunting. As...

W. A. Marrison

1930-01-01T23:59:59.000Z

346

Roughening transition and helium crystals  

Science Journals Connector (OSTI)

Crystal shapes or crystal growth mechanisms depend drastically on whether the crystal surface is smooth or rough, i.e. whether the temperature is lower or higher than its roughening temperature. Helium appeared r...

S. Balibar; F. Gallet; E. Rolley; P. E. Wolf

1985-01-01T23:59:59.000Z

347

Computational analysis of crystallization trials  

Science Journals Connector (OSTI)

A system for the automatic classification of images from crystallization trials for use in conjunction with a high-throughput robotic crystallization platform is described.

Spraggon, G.

2002-10-21T23:59:59.000Z

348

Reversed Doppler Effect in Photonic Crystals  

Science Journals Connector (OSTI)

Nonrelativistic reversed Doppler shifts have never been observed in nature and have only been speculated to occur in pathological systems with simultaneously negative effective permittivity and permeability. This Letter presents a different, new physical phenomenon that leads to a nonrelativistic reversed Doppler shift in light. It arises when light is reflected from a moving shock wave propagating through a photonic crystal. In addition to reflection of a single frequency, multiple discrete reflected frequencies or a 10 GHz periodic modulation can also be observed when a single carrier frequency of wavelength 1????m is incident.

Evan J. Reed; Marin Solja?i?; John D. Joannopoulos

2003-09-23T23:59:59.000Z

349

Photonic crystal fiber interferometer composed of a long period fiber grating and one point collapsing of air holes  

Science Journals Connector (OSTI)

We present an all-fiber interferometer fabricated with a single piece of an endless single-mode photonic crystal fiber (PCF) by an electric arc discharge. By forming a long period...

Choi, Hae Young; Park, Kwan Seob; Lee, Byeong Ha

2008-01-01T23:59:59.000Z

350

Raman scattering in crystals  

SciTech Connect (OSTI)

A tutorial presentation is given of Raman scattering in crystals. The physical concepts are emphasized rather than the detailed mathematical formalism. Starting with an introduction to the concepts of phonons and conservation laws, the effects of photon-phonon interactions are presented. This interaction concept is shown for a simple cubic crystal and is extended to a uniaxial crystal. The correlation table method is used for determining the number and symmetry of the Raman active modes. Finally, examples are given to illustrate the relative ease of using this group theoretical method and the predictions are compared with measured Raman spectra. 37 refs., 17 figs., 6 tabs.

Edwards, D.F.

1988-09-30T23:59:59.000Z

351

Photonic crystal surface-emitting lasers enabled by an accidental Dirac point  

DOE Patents [OSTI]

A photonic-crystal surface-emitting laser (PCSEL) includes a gain medium electromagnetically coupled to a photonic crystal whose energy band structure exhibits a Dirac cone of linear dispersion at the center of the photonic crystal's Brillouin zone. This Dirac cone's vertex is called a Dirac point; because it is at the Brillouin zone center, it is called an accidental Dirac point. Tuning the photonic crystal's band structure (e.g., by changing the photonic crystal's dimensions or refractive index) to exhibit an accidental Dirac point increases the photonic crystal's mode spacing by orders of magnitudes and reduces or eliminates the photonic crystal's distributed in-plane feedback. Thus, the photonic crystal can act as a resonator that supports single-mode output from the PCSEL over a larger area than is possible with conventional PCSELs, which have quadratic band edge dispersion. Because output power generally scales with output area, this increase in output area results in higher possible output powers.

Chua, Song Liang; Lu, Ling; Soljacic, Marin

2014-12-02T23:59:59.000Z

352

Crystals and Plants  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Crystals and Plants Crystals and Plants Name: Diab Location: N/A Country: N/A Date: N/A Question: What will the likely effects of crystallized filaments in plant cells be? I had noticed that moth balls (para dichlorbenzene) tends within a very short temperature range to transform from a solid to gas and back to solid in the form of crystal filaments. I been wondering about the likely effects of an experiment in which a plant is placed in a chamber saturated with the fumes of a substance that had the same transformation properties of its state but none of the toxic effects be on the plants and will such filaments form inside the cell and rearrange its DNA strands or kill it outright? Replies: The following might be helpful: http://biowww.clemson.edu/biolab/mitosis.html http://koning.ecsu.ctstateu.edu/Plant_Physiology/osmosis.html

353

Effect of lithium chloride on spectral, optical, thermal and mechanical behaviour of bis thiourea zinc acetate crystals  

Science Journals Connector (OSTI)

Single crystals of pure bis thiourea zinc acetate (BTZA) and lithium chloride (LiCl) doped BTZA have been synthesized and grown successfully from aqueous solutions by slow evaporation technique. The single crystals thus grown were characterized by different techniques such as single crystal XRD, AAS, FT-IR, UV–Vis, TG/DTA and SHG test. The single crystal XRD study proved that the dopant has not changed the structure of the parent crystal. The AAS study confirmed the presence of lithium in the doped crystal. The FTIR study ascertained the metal coordination of lithium chloride doped BTZA through thiourea. The optical behavior of the doped crystal has been examined by UV spectral analysis. Thermal studies TGA & DTA of the doped crystal have been investigated and found that the doped crystal is thermally more stable than the pure crystal. The SHG test using Nd: YAG Laser confirmed the NLO activity of the pure and doped crystal. The obtained results are presented and discussed.

L. Ruby Nirmala; J. Thomas Joseph Prakash

2012-01-01T23:59:59.000Z

354

Simultaneous presence of (Si{sub 3}O{sub 10}){sup 8?} and (Si{sub 2}O{sub 7}){sup 6?} groups in new synthetic mixed sorosilicates: BaY{sub 4}(Si{sub 2}O{sub 7})(Si{sub 3}O{sub 10}) and isotypic compounds, studied by single-crystal X-ray diffraction, Raman spectroscopy and DFT calculations  

SciTech Connect (OSTI)

Three new, isotypic silicate compounds, BaY{sub 4}(Si{sub 2}O{sub 7})(Si{sub 3}O{sub 10}), SrYb{sub 4}(Si{sub 2}O{sub 7})(Si{sub 3}O{sub 10}) and SrSc{sub 4}(Si{sub 2}O{sub 7})(Si{sub 3}O{sub 10}), were synthesized using high-temperature flux growth techniques, and their crystal structures were solved from single-crystal X-ray intensity data: monoclinic, P2{sub 1}/m, with a=5.532(1)/5.469(1)/5.278(1), b=19.734(4)/19.447(4)/19.221(4), c=6.868(1)/6.785(1)/6.562(1) Å, ?=106.53(3)/106.20(3)/106.50(3)°, V=718.8(2)/693.0(2)/638.3(2) Å{sup 3}, R(F)=0.0225/0.0204/0.0270, respectively. The topology of the novel structure type contains isolated horseshoe-shaped Si{sub 3}O{sub 10} groups (Si–Si–Si=93.15–95.98°), Si{sub 2}O{sub 7} groups (Si–O{sub bridge}–Si=180°, symmetry-restricted) and edge-sharing M(1)O{sub 6} and M(2)O{sub 6} octahedra. Single-crystal Raman spectra of the title compounds were measured and compared with Raman spectroscopic data of chemically and topologically related disilicates and trisilicates, including BaY{sub 2}(Si{sub 3}O{sub 10}) and SrY{sub 2}(Si{sub 3}O{sub 10}). The band assignments are supported by additional theoretical calculation of Raman vibrations by DFT methods. - Graphical abstract: View of BaY{sub 4}(Si{sub 2}O{sub 7})(Si{sub 3}O{sub 10}) along [100], showing zigzag chains and the tri- and disilicate groups. The unit cell is outlined. Display Omitted - Highlights: • We report a novel interesting crystal structure type for mixed sorosilicates containing Y, Yb, and Sc. • Synthesis of such mixed sorosilicates is possible by a high-temperature flux-growth technique. • Calculation of Raman vibrations by advanced DFT methods allows a considerably improved interpretation of measured Raman spectra.

Wierzbicka-Wieczorek, Maria, E-mail: maria.wierzbicka-wieczorek@uni-jena.de [Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Carl-Zeiss-Promenade 10, D-07745 Jena (Germany); Többens, Daniel M. [Abteilung Kristallographie, Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Kolitsch, Uwe [Mineralogisch-Petrographische Abt., Naturhistorisches Museum, Burgring 7, A-1010 Wien (Austria); Institut für Mineralogie und Kristallographie, Universität Wien, Geozentrum, Althanstraße 14, A-1090 Wien (Austria); Tillmanns, Ekkehart [Institut für Mineralogie und Kristallographie, Universität Wien, Geozentrum, Althanstraße 14, A-1090 Wien (Austria)

2013-11-15T23:59:59.000Z

355

Superconducting Proximity Effect in Single-Crystal Nanowires  

E-Print Network [OSTI]

and Zn. This picture is consistent with reports on the PE in carbon nanotubes, semiconductor nanowires, and graphene of length 0.1-0.5 ?m, as well as e-beam patterned Al NWs [59] and electroplated Sn NWs of length up to 4 ?m [60]. However, exceptions...

Liu, Haidong

2010-07-14T23:59:59.000Z

356

Electrochemical Roughening of Au(110) Single Crystal Electrodes  

Science Journals Connector (OSTI)

The surface roughness of a Au(110) electrode was studied as a function of electrode potential. The electrode potential was cycled between the double layer region and the oxide and hydrogen regions. Measurement...

K. M. Robinson; W. E. O’Grady; I. K. Robinson

1992-01-01T23:59:59.000Z

357

Single-crystal germanium growth on amorphous silicon  

E-Print Network [OSTI]

The integration of photonics with electronics has emerged as a leading platform for microprocessor technology and the continuation of Moore's Law. As electronic device dimensions shrink, electronic signals encounter crippling ...

McComber, Kevin A

2011-01-01T23:59:59.000Z

358

Measurement of the resistivity versus temperature in iodine single crystals  

E-Print Network [OSTI]

Me:. . of: the' aygnreti'up. O'M:~e =', ? brana, rod, - C' ln the- oopper blond, ", E . e-, the-. heater. &&re; . . : ';;;!, :; and 8' 9:e ?tIie danplj mounted Xn the ogIindH. oa1, ~11 of' '. ' the pgaQB 8lfclei 1 , -. 9y p1ac&! the. button...&ge ;kanp1e Pre@erat;ao'n', md. "EgM jument -i'=q=, =';~=' . ' IX~, . ". '. :Keasurcdent . of 'Hes5stk~4y as a Pm'@Mon o5 ';" . -'2sinjsrshure. an/ BeitiiICs; ~. ' j -, ', '-'. v ~ . '- . ? t XTjfe. . . '?Df sonation. of Resnlt'8 ~ ~ ~ ' s ~ ', e...

Somoano, Robert Bonner

2012-06-07T23:59:59.000Z

359

Pulse-field actuation of collinear magnetic single crystals  

E-Print Network [OSTI]

Ferromagnetic shape memory alloys (FSMAs) are a class of alloys that exhibits the shape memory effect, as in the alloy nickel-titanium, sometimes known as Nitinol. In FSMAs, though, the shape changes are not brought on ...

Jenkins, Catherine A. (Catherine Ann), 1981-

2004-01-01T23:59:59.000Z

360

THE SYNTHESIS OF MONOCLINIC ZINC DIPHOSPHIDE SINGLE CRYSTALS  

E-Print Network [OSTI]

General Phosphorous Deposit . . . . . . . . . . . . . . . .Ampules Zinc Diphosphide C. Phosphorous Sesquizinc Mechanismi 43, 114 The Zinc-Phosphorous System, L. A. Bitjutskaya, B.

Mowles, Thomas Andrew

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Chapter III: Catalytic Activation of CO Over Single Crystals  

E-Print Network [OSTI]

expected to exist on practical high-surface-area catalysts. This approach allows direct comparison pressure reactor system with an UHV analysis chamber [4-9]. The high pressure reactor allows the kinetics

Goodman, Wayne

362

Mesoporous silicon photonic crystal microparticles: towards single-cell optical  

E-Print Network [OSTI]

in theranostics. Mesoporous silicon, where pores are in the size range of 2�50 nm, is the most relevant material

Kilian, Kristopher A.

363

World's largest single crystal of gold verified by Los Alamos...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

methane levels three times larger than expected over Four Corners region Probing Fukushima with cosmic rays should help speed cleanup of damaged plant Dark spaces could change...

364

Dynamics of crystallization from segregated block copolymer melts  

SciTech Connect (OSTI)

Microphase separation in semicrystalline block copolymers can be driven by two forces: thermodynamic incompatibility between blocks or crystallization of one or more blocks. Prior work has demonstrated that when the block incompatibility is small, crystallization occurs from a single-phase melt and alternating lamellar microdomains result regardless of the copolymer composition. Several experimental studies have examined the time-resolved process of crystallization from single-phase melts. An added complexity in the case of semicrystalline block copolymers which have large block incompatibilities is the possible formation of an ordered melt mesophase; the presence of these microdomains may affect the crystallization process and the resultant morphology. A number of studies have investigated time-resolved crystallization from weakly segregated diblock copolymer melts, concluding that crystallization destroys any pre-existing melt microstructure resulting in a lamellar morphology. We recently reported the statically determined crystallization results for a series of ethylene-block-(3-methyl-1-butene) polymers, which will be referred to as E/MB`s. The composition of each of the polymers in the series was held constant at {approx}26 wt. % E (f{sub E}) block to produce hexagonally packed cylindrical melts, while the molecular weights were altered to obtain varying degrees of incompatibility. Through static scattering measurements, we have clearly shown that a strongly segregated cylindrical melt can confine crystallization to the pre-established microdomains under ordinary processing conditions. In this work, combined synchrotron-based SAXS and WAXS are employed to dynamically follow the microphase separation and crystallization in these materials at both the unit cell and microdomain scales.

Quiram, D.J.; Register, R.A. [Princeton Univ., NJ (United States); Marchand, G.R. [Dow Chemical Co., Plaquemine, LA (United States); Ryan, A.J. [Univ. of Manchester Institute of Science and Technology, MI (United States)

1996-12-31T23:59:59.000Z

365

Electro-optic crystal mosaics for the generation of terahertz radiation  

DOE Patents [OSTI]

Apparatus for the generation of high energy terahertz radiation is presented and comprises laser means effective to produce subpicosecond optical pulses and a mosaic comprising a plurality of planar electro-optic crystals fastened together edge to edge in the form of a grid. The electro-optic crystals are in optical communication with the subpicosecond optical pulses, and behave as a single large electro-optic crystal, producing high energy terahertz radiation by way of optical rectification.

Carrig, Timothy J. (Los Alamos, NM); Taylor, Antoinette J. (Los Alamos, NM); Stewart, Kevin R. (Schenectady, NY)

1996-01-01T23:59:59.000Z

366

Heiniger, Wlti: Novel Single Crystal Diamonds for Waterjet Cutting Applications Novel Single Crystal Diamonds for Waterjet Cutting  

E-Print Network [OSTI]

cutting or wire EDM (electro-discharge machining) the work piece remains cold during the cut- ting process in a wide variety of industries since about 1970. Today no other tool cuts or machines a greater variety-layers (Figure 1). In comparison to the laser machining process, waterjet machining is less expensive

367

MagLab Audio Dictionary: Crystals  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

What are Crystals? Now Playing: What are Crystals? Enable Javascript and Flash to stream the Magnet Minute Chris Wiebe Associated Links Quantum Materials Group New Crystal Growth...

368

Crystal structure of Sr-akermanite glass–ceramics  

Science Journals Connector (OSTI)

A glass–ceramic of Sr-akermanite (Sr2MgSi2O7, SG: P 4 ¯ 2 1 m ) was prepared by crystallization of a glass with composition of 2SrOMgO3SiO2. Parameters of the crystal structure were refined by Rietveld method. The analysis of the experimental results showed the following: the unit cell of Sr-akermanite in the glass–ceramic is larger than in single crystal. The thermal expansion coefficients of Sr-akermanite, calculated from the lattice constants obtained from X-ray diffractograms at high temperatures, were ?a = 3.663 × 10?6 K?1 and ?c = 6.666 × 10?6 K?1. It is suggested that the atomic displacements from the atomic coordination in single crystal depend on the stress developed during the crystallization process and the thermal contraction stress developed during cooling. Both types of stresses are related to the presence of residual glass and should be responsible for the expansion of the crystal lattice.

Yasuo Ochi

2006-01-01T23:59:59.000Z

369

Crystal structure of Sr-akermanite glass-ceramics  

SciTech Connect (OSTI)

A glass-ceramic of Sr-akermanite (Sr{sub 2}MgSi{sub 2}O{sub 7}, SG: P4-bar 2{sub 1}m) was prepared by crystallization of a glass with composition of 2SrO?MgO?3SiO{sub 2}. Parameters of the crystal structure were refined by Rietveld method. The analysis of the experimental results showed the following: the unit cell of Sr-akermanite in the glass-ceramic is larger than in single crystal. The thermal expansion coefficients of Sr-akermanite, calculated from the lattice constants obtained from X-ray diffractograms at high temperatures, were {alpha}{sub a}=3.663x10{sup -6}K{sup -1} and {alpha}{sub c}=6.666x10{sup -6}K{sup -1}. It is suggested that the atomic displacements from the atomic coordination in single crystal depend on the stress developed during the crystallization process and the thermal contraction stress developed during cooling. Both types of stresses are related to the presence of residual glass and should be responsible for the expansion of the crystal lattice.

Ochi, Yasuo [Research and Development Division, Ohara Incorporated Company, Naka 2-22-28, Kunitachi, Tokyo (Japan)]. E-mail: yasuo_ochi@ybb.ne.jp

2006-10-12T23:59:59.000Z

370

Demazure Crystals, Kirillov-Reshetikhin Crystals, and the Energy Function  

E-Print Network [OSTI]

It has previously been shown that, at least for non-exceptional Kac-Moody Lie algebras, there is a close connection between Demazure crystals and tensor products of Kirillov-Reshetikhin crystals. In particular, certain ...

Schilling, Anne

371

Spectroscopy of Eu3+ ions in congruent strontium barium niobate crystals  

E-Print Network [OSTI]

Spectroscopy of Eu3+ ions in congruent strontium barium niobate crystals Ã?. Andresen, A.-N. Bahar properties of single crystals of strontium barium niobate, grown from the congruently melting composition, electro-optic, pho- torefractive, and dielectric properties, the solid solution strontium barium niobate

Osnabrück, Universität

372

ANOMALOUS DISPERSION OF SLOW NEUTRONS IN CRYSTALS By H. G. SMITH and S. W. PETERSON (1),  

E-Print Network [OSTI]

Studies of anomalous scattering of neutrons from CdI2 single crystals were conti- nued over an energy neutron scattering by nuclei and crystals has been fairly well understood for many years. An incident, and depends on the neutron-nucleus interactions. In general, the scattering amplitude can be expressed

Boyer, Edmond

373

Membrane technology for the fabrication of three-dimensional photonic crystals  

E-Print Network [OSTI]

Three-dimensional photonic crystals hold tremendous promise toward the realization of truly integrated photonic circuits on a single substrate. Nanofabrication techniques currently limit the ability to create the multilayer ...

Patel, Amil Ashok, 1979-

2010-01-01T23:59:59.000Z

374

The origin of melt-texture crystal growth process in a simple tube furnace  

Science Journals Connector (OSTI)

The melt-texture growth (MTG) method has been shown to be effective...T csuperconducting bulk samples with highly oriented layers of single crystals. The critical current densityJ

P. C. W. Fung; J. C. L. Chow; T. F. Yu; Z. L. Du

1993-08-01T23:59:59.000Z

375

Optimization of Cylindrical Bent Crystals with Small Radius  

SciTech Connect (OSTI)

To minimize the anticlastic curvature and lower the breaking risk of a sagittal bent crystal with a smaller bending radius, three types of crystal models including the stiffening ribs, the golden value and the assembly with metal were discussed in this paper. Overall structures of the models were predicted and the parameters were optimized by the finite element analysis method. Compared with the results of measurement by long-trace-profiler, theoretical calculations were in good agreed with practical tests. The single-crystal silicon strips glued on the titanium is preferred for the second crystal of the sagittal focusing monochromator at the NSRL-XAFS beamline. Because it not only minimizes the anticlastic distortion but also it achieves small radius less than one meter.

Li Zhongliang; Kang Le; Feng Liangjie; Zhao Feiyun; Xu Chaoyin [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui (China)

2010-06-23T23:59:59.000Z

376

Crystallization of Congo Red  

Science Journals Connector (OSTI)

... It has been confirmed that the potassium salt of Congo Red will crystallize as needles from various ethyl alcohol-water mixtures, but only with ... observation during a trial of various salting-out procedures, however, the potassium salt of Congo Red has been found to be precipitated in crystalline form by salting out with potassium ...

PETER MITCHELL

1950-05-13T23:59:59.000Z

377

Crystals of Platinum and Palladium  

Science Journals Connector (OSTI)

... will be found partially fused. The ribbon upon which crystals have been formed presents a roughened appearance.

J. JOLY

1891-04-09T23:59:59.000Z

378

Photonic crystal heterostructures and interfaces  

Science Journals Connector (OSTI)

Photonic crystal heterostructures, like their semiconductor quantum electronic counterparts, generate complex function from simple, well-understood building blocks. They have led to compact photonic crystal-based waveguides and record-quality-factor resonant cavities. Here the progress on the experimental realization of photonic crystal heterostructure devices, and on the development of convenient, intuitive, and computationally efficient models of devices that unite multiple finite-sized photonic crystal media to engineer photon localization and guidance is summarized.

Emanuel Istrate and Edward H. Sargent

2006-05-16T23:59:59.000Z

379

Ultraslow growth rates of giant gypsum crystals  

Science Journals Connector (OSTI)

...gypsum crystals of Naica ore mines in Chihuahua, Mexico, a challenging subject in mineral...gypsum crystals of Naica ore mines in Chihuahua, Mexico, a challenging subject in...geological timescale. age anhydrite Chihuahua Mexico cooling crystal growth crystallization...

A. E. S. Van Driessche; J. M. García-Ruíz; K. Tsukamoto; L. D. Patiño-Lopez; H. Satoh

2011-01-01T23:59:59.000Z

380

Single-Use Recycling  

Science Journals Connector (OSTI)

Single-use recycling is specially used oil treatment, generating recycled product for a single finite reuse.

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Quantum ferroelectrics of mixed crystals  

Science Journals Connector (OSTI)

The inverse dielectric susceptibility for quantum ferroelectrics in mixed crystals is computed. As in the perfect crystals we find a logarithmic correction to the quantum mean-field theory. For mixed crystals the correction increases faster in the vicinity of the critical point.

D. Schmeltzer

1984-03-01T23:59:59.000Z

382

Toward Single Crystal Thin Films of Terthiophene by Directional Crystallization Using a Thermal Gradient  

Science Journals Connector (OSTI)

We would like to thank Anne de Wit, Pierre Colinet, and Benoît Haut for their help with the heat transfer simulations and Linkam for technical assistance with the hot plate. ... Price, C. P.; Grzesiak, A. L.; Matzger, A. J. J. Am. ...

Guillaume Schweicher; Nicolas Paquay; Claire Amato; Roland Resel; Markus Koini; Samuel Talvy; Vincent Lemaur; Je?ro?me Cornil; Yves Geerts; Gabin Gbabode

2011-06-27T23:59:59.000Z

383

Crystal Plasticity Modelling of Large Strain Deformation in Single Crystals of Magnesium.  

E-Print Network [OSTI]

??Magnesium, with a Hexagonal Close-Packed (HCP) structure, is the eighth most abundant element in the earth’s crust and the third most plentiful element dissolved in… (more)

Izadbakhsh, Adel

2010-01-01T23:59:59.000Z

384

Silicon crystal growing by oscillating crucible technique  

DOE Patents [OSTI]

A process for growing silicon crystals from a molten melt comprising oscillating the container during crystal growth is disclosed.

Schwuttke, G.H.; Kim, K.M.; Smetana, P.

1983-08-03T23:59:59.000Z

385

Water channel structure of bassanite at high air humidity: crystal structure of CaSO4·0.625H2O  

Science Journals Connector (OSTI)

In the presence of high relative air humidity the crystal structure of CaSO4·0.5H2O transforms due to the incorporation of additional water of hydration. The crystal structure of CaSO4·0.625H2O was solved by single-crystal X-ray diffraction at 298 K with 75% relative air humidity.

Schmidt, H.

2011-11-17T23:59:59.000Z

386

Photo of the Week: How to Grow Superconducting Crystals | Department of  

Broader source: Energy.gov (indexed) [DOE]

How to Grow Superconducting Crystals How to Grow Superconducting Crystals Photo of the Week: How to Grow Superconducting Crystals September 13, 2013 - 11:29am Addthis Many of the materials that scientists work with at Brookhaven National Laboratory are too small and too precise for traditional tools. In cases like these, the labs grow materials instead of building them. Brookhaven physicist Genda Gu pioneered techniques that grow some of the largest single-crystal high-temperature superconductors in the world. The glowing chamber in this photo grows superconducting crystals. To do so, the furnace focuses infrared light onto a rod, melting it around 4,000 degrees Fahrenheit. Under just the right conditions, the liquefied material recrystallizes as a single uniform structure, which is highly sensitive and takes about one month to form. | Photo courtesy of Brookhaven National Laboratory.

387

High-heat-load synchrotron tests of room-temperature, silicon crystal monochromators at the CHESS F-2 wiggler station  

SciTech Connect (OSTI)

This note summarizes the results of the single crystal monochromator high-heat-load tests performed at the CHESS F-2 wiggler station. The results from two different cooling geometries are presented: (1) the ``pin-post`` crystal and (2) the ``criss-cross`` crystal. The data presented were taken in August 1993 (water-cooled pin-post) and in April 1995 (water- and gallium-cooled pin-post crystal and gallium-cooled criss-cross crystal). The motivation for trying these cooling (or heat exchanger) geometries is to improve the heat transfer efficiency over that of the conventional slotted crystals. Calculations suggest that the pin-post or the microchannel design can significantly improve the thermal performance of the crystal. The pin-post crystal used here was fabricated by Rocketdyne Albuquerque Operations. From the performance of the conventional slotted crystals, it was thought that increased turbulence in the flow pattern may also enhance the heat transfer. The criss-cross crystal was a simple attempt to achieve the increased flow turbulence. The criss-cross crystal was partly fabricated in-house (cutting, etching and polishing) and bonded by RAO. Finally, a performance comparison among all the different room temperature silicon monochromators that have been tested by the APS is presented. The data includes measurements with the slotted crystal and the core-drilled crystals. Altogether, the data presented here were taken at the CHESS F-2 wiggler station between 1991 and 1995.

Lee, W.K.; Fernandez, P.B.; Graber, T.; Assoufid, L.

1995-09-08T23:59:59.000Z

388

Co-crystals of an agrochemical active – A pyridine-amine synthon for a thioamide group  

Science Journals Connector (OSTI)

Five novel co-crystals of thiophanate-ethyl (TE), an agrochemical active, with di(2-pyridyl)ketone (1), 2-benzoylpyridine (2), 3-benzoylpyridine (3), 4-phenylpyridine (4) and biphenyl (5) were found and crystal structures of four of them (TE1–TE3, TE5) solved by single crystal X-ray diffraction. Three of the co-crystals (TE1–TE3) form by way of a reliable pyridine-amine hydrogen bond synthon and one (TE5) because of close packing effects. The fifth co-crystal was identified by X-ray powder diffraction. The work demonstrates the usage of a reliable supramolecular synthon for crystal engineering, while concurrently reminds that the close packing of even very similar molecules cannot be fully predicted.

E. Nauha; M. Nissinen

2011-01-01T23:59:59.000Z

389

32 - Fundamentals of Industrial Crystallization  

Science Journals Connector (OSTI)

Abstract Industrial crystallization processes aim at the large-scale production of crystalline products through the formation of involving a suspension of growing particles in a solution. The product quality is defined by the kind of crystalline phase produced, the crystal size distribution, the crystal morphology, and the product purity. These product quality aspects are determined by the subprocesses of crystallization of which crystal nucleation and growth are usually of main importance. The driving force for these subprocesses is usually established either by evaporating solvent to increase the concentration or cooling the solution to decrease the solubility. The recent pharmaceutical research interest in continuous crystallization processes is fortified by claims of improved product quality, efficient use of materials and energy resources, and waste stream reductions.

Joop H. ter Horst; Christiane Schmidt; Joachim Ulrich

2015-01-01T23:59:59.000Z

390

High rotation speed of single molecular microcrystals in an optical trap with elliptically polarized light  

Science Journals Connector (OSTI)

We build an experiment of optical tweezers based on the use of an inverted optical microscope for manipulating microsized single crystals, which are made of an organic dye and...

Rodriguez-Otazo, Mariela; Augier-Calderin, Angel; Galaup, Jean-Pierre; Lamère, Jean-François; Fery-Forgues, Suzanne

2009-01-01T23:59:59.000Z

391

Florida Nuclear Profile - Crystal River  

U.S. Energy Information Administration (EIA) Indexed Site

Crystal River1" "Unit","Summer capacity (mw)","Net generation (thousand mwh)","Summer capacity factor (percent)","Type","Commercial operation date","License expiration date"...

392

Aperiodic crystals and superspace concepts  

Science Journals Connector (OSTI)

Aperiodic crystals may conveniently be described in a higher dimensional `superspace'. An overview of the method and applications to various families is given.

Janssen, T.

2014-07-31T23:59:59.000Z

393

Invisible defects in complex crystals  

E-Print Network [OSTI]

We show that invisible localized defects, i.e. defects that can not be detected by an outside observer, can be realized in a crystal with an engineered imaginary potential at the defect site. The invisible defects are synthesized by means of supersymmetric (Darboux) transformations of an ordinary crystal using band-edge wave functions to construct the superpotential. The complex crystal has an entire real-valued energy spectrum and Bragg scattering is not influenced by the defects. An example of complex crystal synthesis is presented for the Mathieu potential.

S. Longhi; G. Della Valle

2013-06-04T23:59:59.000Z

394

BY SILICON CRYSTALS  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

c October 29, 1942 a 1 1 _MIGH aECTgFXCATIOH - BY SILICON CRYSTALS . . c .. I n. The excellent pesformmce of Brftieh "red dot" c r y s t a l s f e explained R R due t o the kgife edge contact i n a t A polfehod ~ X ' f l i C B o H i g h frequency m c t l f f c n t f o n 8ependre c r i t i c a l l y on the ape%e;y of the rectifytnc boundary layer o f the crystal, C, For hl#$ comvere~on e f f i c i e n c y , the product c d t h i ~ capacity m a o f ' t h e @forward" (bulk) re-. sistance Rb o f the crystnl must b@ sm%P, depende primarily on the breadth of tha b f f e edge i t s lbngth. The contact am &harefore ~ E L V Q a rather large area wMQh prevents burn-out, thh3 t h e breadth of &h@ knife edge should be bdt8~1 than E~$O$B% % f I - ' amo For a knife edge, this produet very 14ttle upom For a wavsIL~n+3tih of PO emo the eowp,o%a%8sne 4

395

Synthesis, Growth, and Properties of TlGa{sub 1-x}Yb{sub x}S{sub 2} Crystals  

SciTech Connect (OSTI)

The synthesis of TlGa{sub 1-x}Yb{sub x}S{sub 2} single crystals with the partial substitution of ytterbium for gallium is described. Variations in the electric conductivity of grown crystals irradiated with X-rays of various intensities are measured.

Kerimova, E.M.; Mustafaeva, S.N.; Asadov, Yu.G.; Kerimov, R.N. [Institute of Physics, National Academy of Sciences, pr. Dzhavida 33, Baku, 370143 (Azerbaijan)

2005-12-15T23:59:59.000Z

396

Fast quantum dot single photon source triggered at telecommunications wavelength  

E-Print Network [OSTI]

We demonstrate a quantum dot single photon source at 900 nm triggered at 300 MHz by a continuous wave telecommunications wavelength laser followed by an electro-optic modulator. The quantum dot is excited by on-chip-generated second harmonic radiation, resonantly enhanced by a GaAs photonic crystal cavity surrounding the InAs quantum dot. Our result suggests a path toward the realization of telecommunications-wavelength-compatible quantum dot single photon sources with speeds exceeding 1 GHz.

Kelley Rivoire; Sonia Buckley; Arka Majumdar; Hyochul Kim; Pierre Petroff; Jelena Vuckovic

2010-12-01T23:59:59.000Z

397

Ultraslow growth rates of giant gypsum crystals  

Science Journals Connector (OSTI)

...gypsum crystals of Naica ore mines in Chihuahua, Mexico, a challenging subject in mineral...gypsum crystals of Naica ore mines in Chihuahua, Mexico, a challenging subject...gypsum crystals of Naica ore mines in Chihuahua, Mexico, a challenging subject...

A. E. S. Van Driessche; J. M. García-Ruíz; K. Tsukamoto; L. D. Patiño-Lopez; H. Satoh

2011-01-01T23:59:59.000Z

398

Tapered fiber coupling of single photons emitted by a deterministically positioned single nitrogen vacancy center  

SciTech Connect (OSTI)

A diamond nano-crystal hosting a single nitrogen vacancy (NV) center is optically selected with a confocal scanning microscope and positioned deterministically onto the subwavelength-diameter waist of a tapered optical fiber (TOF) with the help of an atomic force microscope. Based on this nano-manipulation technique, we experimentally demonstrate the evanescent coupling of single fluorescence photons emitted by a single NV-center to the guided mode of the TOF. By comparing photon count rates of the fiber-guided and the free-space modes and with the help of numerical finite-difference time domain simulations, we determine a lower and upper bound for the coupling efficiency of (9.5?±?0.6)% and (10.4?±?0.7)%, respectively. Our results are a promising starting point for future integration of single photon sources into photonic quantum networks and applications in quantum information science.

Liebermeister, Lars, E-mail: lars.liebermeister@physik.uni-muenchen.de; Petersen, Fabian; Münchow, Asmus v.; Burchardt, Daniel; Hermelbracht, Juliane; Tashima, Toshiyuki [Fakultät für Physik, Ludwig-Maximilians-Universität München, 80799 München (Germany); Schell, Andreas W.; Benson, Oliver [Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin (Germany); Meinhardt, Thomas; Krueger, Anke [Institut für Organische Chemie, Universität Würzburg, 97074 Würzburg (Germany); Wilhelm Conrad Roentgen Research Center for Complex Materials Systems, Universität Würzburg, 97074 Würzburg (Germany); Stiebeiner, Ariane; Rauschenbeutel, Arno [Atominstitut, Technische Universität Wien, 1020 Wien (Austria); Weinfurter, Harald; Weber, Markus, E-mail: markusweber@lmu.de [Fakultät für Physik, Ludwig-Maximilians-Universität München, 80799 München (Germany); Max-Planck-Institut für Quantenoptik, 85748 Garching (Germany)

2014-01-20T23:59:59.000Z

399

Laser Crystallization of Phase Change Material  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Geoffrey Campbell is the Principal Investigator for Laser Crystallization of Phase Change Material LLNL BES Programs Highlight Laser Crystallization of Phase Change Material False...

400

Radiopurity of CaWO$_4$ Crystals for Direct Dark Matter Search with CRESST and EURECA  

E-Print Network [OSTI]

The direct dark matter search experiment CRESST uses scintillating CaWO$_4$ single crystals as targets for possible WIMP scatterings. An intrinsic radioactive contamination of the crystals as low as possible is crucial for the sensitivity of the detectors. In the past CaWO$_4$ crystals operated in CRESST were produced by institutes in Russia and the Ukraine. Since 2011 CaWO$_4$ crystals have also been grown at the crystal laboratory of the Technische Universit\\"at M\\"unchen (TUM) to better meet the requirements of CRESST and of the future tonne-scale multi-material experiment EURECA. The radiopurity of the raw materials and of first TUM-grown crystals was measured by ultra-low background $\\gamma$-spectrometry. Two TUM-grown crystals were also operated as low-temperature detectors at a test setup in the Gran Sasso underground laboratory. These measurements were used to determine the crystals' intrinsic $\\alpha$-activities which were compared to those of crystals produced at other institutes. The total $\\alpha$...

Münster, A; Angloher, G; Bento, A; Bucci, C; Canonica, L; Erb, A; Feilitzsch, F v; Gorla, P; Gütlein, A; Hauff, D; Jochum, J; Kraus, H; Lanfranchi, J -C; Laubenstein, M; Loebell, J; Ortigoza, Y; Petricca, F; Potzel, W; Pröbst, F; Puimedon, J; Reindl, F; Roth, S; Rottler, K; Sailer, C; Schäffner, K; Schieck, J; Scholl, S; Schönert, S; Seidel, W; Stodolsky, L; Strandhagen, C; Strauss, R; Tanzke, A; Uffinger, M; Ulrich, A; Usherov, I; Wawoczny, S; Willers, M; Wüstrich, M; Zöller, A

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Polarization singularities of optical fields caused by structural dislocations in crystals  

Science Journals Connector (OSTI)

We analyze polarization singularities of optical beams that propagate through crystals possessing structural dislocations. We show that screw dislocations of crystalline structure can lead to the appearance of purely screw-type dislocations of light wavefronts. This can happen only in crystals that belong to trigonal and cubic systems. These polarization singularities will give rise to optical vortices with the topological charge equal to ±1, whenever a crystal sample is placed between crossed circular polarizers. We have also found that edge dislocations present in the cubic and trigonal crystals, with the Burgers vector perpendicular to the three-fold symmetry axes, can impose mixed screw-edge dislocations in the wavefronts of optical beams and generate singly charged optical vortices. The results of our analysis can be applied for detecting and identifying dislocations of different types available in crystals.

V Savaryn; Yu Vasylkiv; O Krupych; I Skab; R Vlokh

2013-01-01T23:59:59.000Z

402

Molecular structures and crystal packings of 2-styrylquinoline and its derivatives  

SciTech Connect (OSTI)

The crystal and molecular structures of five styrylheterocycles of the quinoline series are studied. All molecules are planar. The double bond in the ethylene fragment is essentially localized. In the molecule of 2-(4-methylstyryl)quinoline, the ethylene fragment is disordered by the bicycle-pedal pattern. In four of the five compounds, the crystal packings do not contain stacking dimers prearranged for the [2+2] photocycloaddition (PCA) reaction. In the crystal of 2-(3-nitrostyryl)quinoline, pairs of crystallographically independent molecules form stacking dimers. In a dimer, the ethylene fragments have a twist orientation, which is incompatible with the PCA reaction. An attempt to initiate a temperature-dependent process of bicyclepedal isomerization in the crystal and, as a consequence, the PCA reaction by means of simultaneous irradiation and heating of a single crystal is unsuccessful.

Kuz'mina, L. G., E-mail: kuzmina@igic.ras.ru [Russian Academy of Sciences, Kurnakov Institute of General and Inorganic Chemistry (Russian Federation); Sitin, A. G. [Mendeleev University of Chemical Technology of Russia (Russian Federation); Gulakova, E. N.; Fedorova, O. A. [Russian Academy of Sciences, Nesmeyanov Institute of Organoelement Compounds (Russian Federation); Lermontova, E. Kh.; Churakov, A. V. [Russian Academy of Sciences, Kurnakov Institute of General and Inorganic Chemistry (Russian Federation)

2011-07-15T23:59:59.000Z

403

Room-temperature serial crystallography using a kinetically optimized microfluidic device for protein crystallization and on-chip X-ray diffraction  

Science Journals Connector (OSTI)

An emulsion-based serial crystallographic technology has been developed, in which single crystals are grown in nanolitre-sized droplets inside an X-ray semi-transparent microfluidic chip exploiting a negative feedback mechanism. Diffraction data are measured, one crystal at a time, from a series of room-temperature crystals stored in the chip, and a 93% complete data set is obtained by merging single diffraction frames taken from different unoriented crystals to solve the structure of glucose isomerase to 2.1 ?.

Heymann, M.

2014-08-25T23:59:59.000Z

404

Synthesis and crystal structure studies of ethyl 5-methyl-1, 3-diphenyl-1H-pyrazole-4-carboxylate  

SciTech Connect (OSTI)

The title compound, C{sub 19}H{sub 18}N{sub 2}O{sub 2}, was investigated by single crystal X-ray diffraction method. It crystallizes in monoclinic class under the space group P2{sub 1}/c with cell parameters a= 8.4593(4) Å, b=15.6284(6) Å, c=12.4579(5) Å, ?=90°, ?=98.241(3)°, ?=90° and Z=2. The ethoxycarbonyl group is slightly twisted from the pyrazole ring, and adopts syn-periplanar conformation. The crystal structure is stabilized by intermolecular C-H….O hydrogen bonds, which help in stabilizing the crystal structure.

Chandra,; Babu, E. A. Jithesh; Mahendra, M., E-mail: mahendra@physics.uni-mysore.ac.in [Department of Studies in Physics, Manasagangotri, University of Mysore, Mysore-570006 (India); Srikantamurthy, N.; Umesha, K. B. [Department of Chemistry, Yuvaraja's College, University of Mysore, Mysore-570005 (India)

2014-04-24T23:59:59.000Z

405

X-Ray Crystallography What do you need? A crystal. But not just any crystal a well ordered crystal  

E-Print Network [OSTI]

X-Ray Crystallography What do you need? A crystal. But not just any crystal­ a well ordered crystal that will diffract x-rays strongly. A crystal handedness. This reduces number to 6- 12. #12;#12;Generally X-ray beam

Cavanagh, John

406

Single-Molecule Detection  

Science Journals Connector (OSTI)

Detection of single molecules represents the ultimate level of sensitivity and ... background, fluorescence is one obvious choice for single-molecule detection (SMD). However, SMD using ... first report on SMD us...

2006-01-01T23:59:59.000Z

407

Enhanced photoacoustic detection using photonic crystal substrate  

SciTech Connect (OSTI)

This paper demonstrates the enhanced photoacoustic sensing of surface-bound light absorbing molecules and metal nanoparticles using a one-dimensional photonic crystal (PC) substrate. The PC structure functions as an optical resonator at the wavelength where the analyte absorption is strong. The optical resonance of the PC sensor provides an intensified evanescent field with respect to the excitation light source and results in enhanced optical absorption by surface-immobilized samples. For the analysis of a light absorbing dye deposited on the PC surface, the intensity of photoacoustic signal was enhanced by more than 10-fold in comparison to an un-patterned acrylic substrate. The technique was also applied to detect gold nanorods and exhibited more than 40 times stronger photoacoustic signals. The demonstrated approach represents a potential path towards single molecule absorption spectroscopy with greater performance and inexpensive instrumentation.

Zhao, Yunfei; Liu, Kaiyang [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); McClelland, John [Ames Laboratory-USDOE, Ames, Iowa 50011 (United States); Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States); Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011 (United States); Lu, Meng, E-mail: menglu@iastate.edu [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States)

2014-04-21T23:59:59.000Z

408

mathematics single cycle  

E-Print Network [OSTI]

47 mathematics education single cycle master's study programme #12;48 single cycle master's study program in Mathematics Education #12;49 single cycle master's study program in Mathematics Education MATHEMATICS EDUCATION The program is in tune with the principles of the Bologna Declaration. · Academic title

Â?umer, Slobodan

409

Continuous API-crystal coating via coacervation in a tubular reactor  

Science Journals Connector (OSTI)

Abstract We present a proof-of-concept study of a continuous coating process of single API crystals in a tubular reactor using coacervation as a microencapsulation technique. Continuous API crystal coating can have several advantages, as in a single step (following crystallization) individual crystals can be prepared with a functional coating, either to change the release behavior, to protect the API from gastric juice or to modify the surface energetics of the API (i.e., to tailor the hydrophobic/hydrophilic characteristics, flowability or agglomeration tendency, etc.). The coating process was developed for the microencapsulation of a lipophilic core material (ibuprofen crystals of 20 ?m- to 100 ?m-size), with either hypromellose phthalate (HPMCP) or Eudragit L100-55. The core material was suspended in an aqueous solution containing one of these enteric polymers, fed into the tubing and mixed continuously with a sodium sulfate solution as an antisolvent to induce coacervation. A subsequent temperature treatment was applied to optimize the microencapsulation of crystals via the polymer-rich coacervate phase. Cross-linking of the coating shell was achieved by mixing the processed material with an acidic solution (pH < 3). Flow rates, temperature profiles and polymer-to-antisolvent ratios had to be tightly controlled to avoid excessive aggregation, leading to pipe plugging. This work demonstrates the potential of a tubular reactor design for continuous coating applications and is the basis for future work, combining continuous crystallization and coating.

M.O. Besenhard; A. Thurnberger; R. Hohl; E. Faulhammer; J. Rattenberger; J.G. Khinast

2014-01-01T23:59:59.000Z

410

Heat transport through ion crystals  

E-Print Network [OSTI]

We study the thermodynamical properties of crystals of trapped ions which are laser cooled to two different temperatures in two separate regions. We show that these properties strongly depend on the structure of the ion crystal. Such structure can be changed by varying the trap parameters and undergoes a series of phase transitions from linear to zig-zag or helicoidal configurations. Thus, we show that these systems are ideal candidates to observe and control the transition from anomalous to normal heat transport. All structures behave as `heat superconductors', with a thermal conductivity increasing linearly with system size and a vanishing thermal gradient inside the system. However, zig-zag and helicoidal crystals turn out to be hyper sensitive to disorder having a linear temperature profile and a length independent conductivity. Interestingly, disordered 2D ion crystals are heat insulators. Sensitivity to disorder is much smaller in the 1D case.

Nahuel Freitas; Esteban Martinez; Juan Pablo Paz

2013-12-23T23:59:59.000Z

411

Crystal-Like geometric modeling  

E-Print Network [OSTI]

faces, symmetry, and fractal geometry. The techniques have also been implemented in software, as a proof of concept. They are used in an interactive geometric modeling system, in which users can use these techniques to create crystal-like shapes...

Landreneau, Eric Benjamin

2006-08-16T23:59:59.000Z

412

Crystal Growth of Oxide and Sulphide  

Science Journals Connector (OSTI)

......film. The hexagonal shaped crystal was often formed on a needle crystals. One of the electron diffraction...the diffraction patterns of bent crystals, the unit cell of this crystal...was often observed that the spherical particles like dew drops......

Hatsujiro HASHIMOTO

1960-01-01T23:59:59.000Z

413

Graphene-based polaritonic crystal  

Science Journals Connector (OSTI)

It is shown that monolayer graphene deposited on a spatially periodic gate behaves as a polaritonic crystal. Its band structure depending on the applied gate voltage is studied. The scattering of electromagnetic radiation from such a crystal is presented calculated and its spectral dependence is analyzed in terms of Fano-type resonances between the reflected continuum and plasmon-polariton modes forming narrow bands.

Yu. V. Bludov; N. M. R. Peres; M. I. Vasilevskiy

2012-06-05T23:59:59.000Z

414

Neutron diffraction by perfect crystals  

Science Journals Connector (OSTI)

The dynamical theory of neutron diffraction has been formulated to include the reflected waves from the boundaries of a crystal. This formulation allows a unified treatment of the neutron optical and diffraction phenomena in crystals. It is shown that the neutron propagation in the crystal is determined by two structure factors characterizing the lattice: the total structure factor and the structure factor of the neutron-spin-neutron-orbit interaction. Diffraction by a parallel crystal plate has been studied in considerable detail. It has been found that for a definite neutron-spin orientation, the diffracted and transmitted beams are modulated by six terms periodic in the thickness of the crystal. The period of the dominant term, in this Pendellösung fringe structure, has been calculated in several cases of experimental importance. If the glancing angle of incidence substantially exceeds the critical angle for total reflection, the results are identical with those obtained by a simple extension, to the neutron case, of the x-ray dynamical theory. The diffraction by a magnetized crystal has been examined in some detail and it is shown that measurement of the Pendellösung periods for the two neutron-spin orientations may be used to determine both the nuclear and magnetic neutron scattering amplitude.

C. Stassis and J. A. Oberteuffer

1974-12-15T23:59:59.000Z

415

Coherent Interaction of Light and Single Molecules in a Dielectric Nanoguide  

E-Print Network [OSTI]

We present a new scheme for performing optical spectroscopy on single molecules. A glass capillary with a diameter of 600 nm filled with an organic crystal tightly guides the excitation light and provides a maximum spontaneous emission coupling factor ($\\beta$) of 18% for the dye molecules doped in the organic crystal. Combination of extinction, fluorescence excitation and resonance fluorescence spectroscopy with microscopy provides high-resolution spatio-spectral access to a very large number of single molecules in a linear geometry. We discuss strategies for exploring a range of quantum optical phenomena, including coherent cooperative interactions in a mesoscopic ensemble of molecules mediated by a single mode of propagating photons.

Faez, Sanli; Haakh, Harald R; Götzinger, Stephan; Sandoghdar, Vahid

2014-01-01T23:59:59.000Z

416

Optimal feedback in efficient single-cavity optical parametric oscillators  

SciTech Connect (OSTI)

An approach based on the description of competition of quadratic processes of merging and decomposition of quanta resulting in the formation of cnoidal waves on an effective cascade cubic Kerr-type nonlinearity is used to optimise the scheme of a single-cavity optical parametric oscillator. It is shown that the use of a feedback circuit (cavity) decreases the period of cnoidal waves produced in a nonlinear crystal, while the optimisation procedure of the transfer constant of this circuit (reflectivity of the output mirror of the cavity) is reduced to matching this period with the nonlinear crystal length. (optical parametric oscillators)

Petnikova, V M; Shuvalov, Vladimir V [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation)

2010-09-10T23:59:59.000Z

417

Annealing of single lamella nanoparticles of polyethylene  

E-Print Network [OSTI]

We study the change of the size and structure of freely suspended single lamella nanoparticles of polyethylene during thermal annealing in aqueous solutions. Using small-angle x-ray scattering and cryogenic transmission electron microscopy, it is shown that a doubling of the crystalline lamella sandwiched between two amorphous polymer layers is obtained by annealing the nanoparticles at 125 C. This thickening of the crystalline lamella can be understood in terms of an unlooping of polymer chains within a single nanoparticle. In addition a variation of the annealing temperature from 90 C to 115 C demonstrates that the inverse of the crystalline lamellar thickness increases linearly with the annealing temperatures leading to a recrystallization line in a Gibbs-Thomson graph. Since the nanoparticles consist of about only eight polymer chains, they can be considered as a ideal candidates for the experimental realization of equilibrium polymer crystals.

Christophe N. Rochette; Sabine Rosenfeldt; Katja Henzler; Frank Polzer; Matthias Ballauff; Qiong Tong; Stefan Mecking; Markus Drechsler; Theyencheri Narayanan; Ludger Harnau

2011-07-05T23:59:59.000Z

418

Toward photonic-crystal metamaterials: Creating magnetic emitters in photonic crystals  

E-Print Network [OSTI]

Toward photonic-crystal metamaterials: Creating magnetic emitters in photonic crystals M. L Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge explore the possibility of designing photonic crystals to act as magnetic metamaterials: structures

419

Crystal Systems | Open Energy Information  

Open Energy Info (EERE)

Crystal Systems Crystal Systems Name Crystal Systems Address 27 Congress Street Place Salem, Massachusetts Zip 01970 Sector Solar Product Silicon producer Year founded 1971 Website http://www.crystalsystems.com/ Coordinates 42.5190384°, -70.8896271° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":42.5190384,"lon":-70.8896271,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

420

Calibrating Curved Crystals Used for Plasma Spectroscopy  

SciTech Connect (OSTI)

The throughput and resolving power of an X-ray spectrometer that uses a curved crystal as the diffraction element is determined primarily by the crystal X-ray reflectivity properties. This poster presents a measurement technique for these crystal parameters using a simple diode source to produce a narrow spectral band. The results from measurements on concave elliptical polyethylene terephthalate (PET) crystals and convex potassium acid phthalate (KAP) crystals show large variations in the key parameters compared to those from the flat crystal.

Haugh, M. J., Jacoby, K. D., Ross, P. W., Rochau, G. Wu, M., Regan, S. P., Barrios, M. A.

2012-10-29T23:59:59.000Z

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Precision Crystal Calorimeters in High Energy Physics  

ScienceCinema (OSTI)

Precision crystal calorimeters traditionally play an important role in high energy physics experiments. In the last two decades, it faces a challenge to maintain its precision in a hostile radiation environment. This paper reviews the performance of crystal calorimeters constructed for high energy physics experiments and the progress achieved in understanding crystal?s radiation damage as well as in developing high quality scintillating crystals for particle physics. Potential applications of new generation scintillating crystals of high density and high light yield, such as LSO and LYSO, in particle physics experiments is also discussed.

Ren-Yuan Zhu

2010-01-08T23:59:59.000Z

422

N-HO and C-HF hydrogen bonds in the incommensurately modulated crystal structure of adamantan-1-ammonium 4-fluorobenzoate  

Science Journals Connector (OSTI)

The incommensurately modulated crystal structure and the intermolecular interactions of the organic salt C10H18N+?C7H4FO2- are studied by analysing single-crystal X-ray diffraction data within the (3+1)-dimensional superspace approach and superspace group P21/n(0)00.

Sch?nleber, A.

2014-07-31T23:59:59.000Z

423

Journal of Physics and Chemistry of Solids 67 (2006) 25122516 Crystal chemistry of layered carbide, Ti3(Si0.43Ge0.57)C2  

E-Print Network [OSTI]

Journal of Physics and Chemistry of Solids 67 (2006) 2512­2516 Crystal chemistry of layered carbide structure of a layered ternary carbide, Ti3(Si0.43Ge0.57)C2, was studied with single-crystal X structure 1. Introduction Layered carbides and nitrides, or the so-called Mn+1AXn (MAX) phases, where n is 1

Downs, Robert T.

424

Simulation of the Extinction Efficiency, the Absorption Efficiency and the Asymmetry Factor of Ice Crystals and Relevant Applications to the Study of Cirrus Cloud Radiative Properties  

E-Print Network [OSTI]

The single-scattering properties of six non-spherical ice crystals, droxtals, plates, solid columns, hollow columns, aggregates and 6-branch bullet rosettes are simulated. The anomalous diffraction theory (ADT) is applied to the simulation...

Lu, Kai

2010-10-12T23:59:59.000Z

425

Sintering behavior of two roughened crystals just after contact  

E-Print Network [OSTI]

We consider two spherical, roughened crystals with approximately isotropic surface free energy which are brought into contact and begin to sinter. We argue that the geometry immediately post-contact is two dimensional and Cartesian and can be approximated by the evolution of a slot-shaped cavity. On this basis, we construct travelling wave solutions for the crystal shape in the limits of bulk diffusion limited and surface diffusion limited kinetics. These solutions are then used to calculate novel scalings for the neck size as a function of time $t$ after contact: We predict that neck size is proportional to $t^{1/4}$ for the bulk diffusion limited case and (following a single pinch-off event) approximately proportional to $t^{1/3}$ for the surface diffusion limited case.

R. S. Farr; M. J. Izzard

2010-01-22T23:59:59.000Z

426

Forming of Magnesium - Crystal Plasticity and Plastic Potentials  

SciTech Connect (OSTI)

Hexagonal close-packed (hcp) metals show a deformation behavior, which is quite different from that of materials with cubic crystalline structure. As a consequence, rolled or extruded products of magnesium and its alloys exhibit a strong anisotropy and an unlike yielding in tension and compression. Microstructural mechanisms of deformation in pure magnesium are modeled by constitutive equations of crystal plasticity. Single crystals and textured polycrystals are analyzed numerically. By means of virtual mechanical tests of representative volume elements mesoscopic yield surfaces are generated and compared with phenomenological yield surfaces. The hardening behavior as well as deformation kinematics are accounted while fitting the respective model parameters for a plane stress state. The linking of micro- and mesoscale provides a procedure for the simulation of the yielding and hardening behavior of arbitrarily textured solids with hcp structure such as extruded bars or rolled plates.

Steglich, Dirk; Graff, Stephane; Brocks, Wolfgang [GKSS Research Center, Institute for Materials Research, Mechanics of Materials, Geesthacht (Germany)

2007-04-07T23:59:59.000Z

427

X-ray imaging crystal spectrometer for extended X-ray sources  

DOE Patents [OSTI]

Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokomak fusion experiment to provide spatially and temporally resolved data on plasma parameters using the imaging properties for Bragg angles near 45. For a Bragg angle of 45.degree., the spherical crystal focuses a bundle of near parallel X-rays (the cross section of which is determined by the cross section of the crystal) from the plasma to a point on a detector, with parallel rays inclined to the main plain of diffraction focused to different points on the detector. Thus, it is possible to radially image the plasma X-ray emission in different wavelengths simultaneously with a single crystal.

Bitter, Manfred L. (Princeton, NJ); Fraenkel, Ben (Jerusalem, IL); Gorman, James L. (Bordentown, NJ); Hill, Kenneth W. (Lawrenceville, NJ); Roquemore, A. Lane (Cranbury, NJ); Stodiek, Wolfgang (Princeton, NJ); von Goeler, Schweickhard E. (Princeton, NJ)

2001-01-01T23:59:59.000Z

428

ARM - Field Campaign - CRYSTAL-FACE  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

govCampaignsCRYSTAL-FACE govCampaignsCRYSTAL-FACE Campaign Links CRYSTAL-FACE Website Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : CRYSTAL-FACE 2002.06.26 - 2002.08.01 Lead Scientist : James Mather Data Availability Data is available to the general public at the ARM Archive. Questions regarding CRYSTAL-FACE or the PARSL data set may be directed to Jim Mather at the Pacific Northwest National Laboratory (Jim.Mather@pnl.gov) or visit the CRYSTAL-FACE web site at http://cloud1.arc.nasa.gov/crystalface/ For data sets, see below. Description From July 3-29, 2002 ARM took part in CRYSTAL-FACE (The Cirrus Regional Study of Tropical Anvils and Cirrus Layers -Florida Area Cirrus Experiment). CRYSTAL-FACE was organized by NASA but many agencies and

429

IR laser-induced protein crystal transformation  

Science Journals Connector (OSTI)

A novel method and the associated instrumentation for improving crystalline order (higher resolution of X-ray diffraction and reduced mosaicity) of protein crystals by precisely controlled heating is demonstrated. Crystal transformation is optically controlled by a video system.

Kiefersauer, R.

2014-04-26T23:59:59.000Z

430

Fluid Inclusions in Hydrothermally Synthesized Brucite Crystals  

Science Journals Connector (OSTI)

Brucite crystals were grown hydrothermally from Mg(OH)2 powder in 7.5 and 15 mol% NaOH solutions. It is established from the observation of the surface microtopographs that the crystals grew by the spiral mechani...

Kazuo Nakamura; Shin-Ichi Hirano…

1989-01-01T23:59:59.000Z

431

Crystallization of the crenarchaeal SRP core  

Science Journals Connector (OSTI)

The conserved ribonucleoprotein core of the signal recognition particle (SRP) has been crystallized. Both crystal forms are highly twinned and an explanation for the possible tetartohedral twinning is presented.

Rosendal, K.R.

2003-12-18T23:59:59.000Z

432

Nanopatterned anchoring layers for liquid crystals  

E-Print Network [OSTI]

This thesis describes the theory and fabrication of inhomogeneous Liquid Crystal anchoring layers. While chemical anchoring techniques have proved useful for many applications, especially Liquid Crystal Displays, they have ...

Gear, Christopher S. (Christopher Stanwood)

2014-01-01T23:59:59.000Z

433

Technique for anisotropic extension of organic crystals: Application to temperature dependence of electrical resistance  

Science Journals Connector (OSTI)

We have developed a technique for the anisotropic extension of fragile molecular crystals. The pressure medium and the instrument which extends the pressure medium are both made from epoxy resin. Since the thermal contraction of our instrument is identical to that of the pressure medium the strain applied to the pressure medium has no temperature dependence down to 2 K . Therefore the degree of extension applied to the single crystal at low temperatures is uniquely determined from the degree of extension in the pressure medium and thermal contractions of the epoxy resin and the single crystal at ambient pressure. Using this novel instrument we have measured the temperature dependence of the electrical resistance of metallic superconducting and insulating materials. The experimental results are discussed from the viewpoint of the extension (compression) of the lattice constants along the parallel (perpendicular) direction.

Takashi Yamamoto; Reizo Kato; Hiroshi M. Yamamoto; Atsuko Fukaya; Kenji Yamasawa; Ichiro Takahashi; Hiroki Akutsu; Akane Akutsu-Sato; Peter Day

2007-01-01T23:59:59.000Z

434

8 - Hydrothermal Synthesis and Crystal Growth of Fluorides, Sulfides, Tungstates, Molybdates, and Related Compounds (Coordinated Complex Crystals, Part II)  

Science Journals Connector (OSTI)

In Chapter 8 we deal with fluorides, sulfides, tungstates, titanates, molybdates, tantalates, neobates, selenides, and related compounds. The synthesis of these compounds did not carry much geological significance in the past; hence, their synthesis began in the middle of the twentieth century. However, the interest was purely academic. Today, these compounds have a great technological significance. Although the synthesis of these compounds is being studied extensively worldwide, interest is more confined to the nanosize crystals rather than the bulk single crystals growth. Some of these coordinated complexes with reductions in the size and the establishment of core-shell structures carry special characteristics useful as sensors, quantum dots, imagers, semiconductors over a wide band gap region, and so on. Keywords hermothermal phase equilibria; rich substitutional chemistry; antiferromagnetic behavior; rare earth flurides; oxyfluorinated compounds; photoconductivity

K. Byrappa; Masahiro Yoshimura

2013-01-01T23:59:59.000Z

435

Crystal Engineering: Strategies and Architectures  

Science Journals Connector (OSTI)

This review takes a look at some of the strategies that have been devised for research in crystal engineering, in particular, those based around hydrogen-bonded architectures. In addition, some of the history and possibilites of the field itself are alluded to.

Aakeröy, C.B.

1997-08-01T23:59:59.000Z

436

Neutron Production from Feedback Controlled Thermal Cycling of a Pyroelectric Crystal Stack  

SciTech Connect (OSTI)

The LLNL Crystal Driven Neutron Source is operational and has produced record ion currents of {approx}10 nA and neutron output of 1.9 ({+-}0.3) x 10{sup 5} per thermal cycle using a crystal heating rate of 0.2 C/s from 10 C to 110 C. A 3 cm diameter by 1 cm thick LiTaO{sub 3} crystal with a socket secured field emitter tip is thermally cycled with feedback control for ionization and acceleration of deuterons onto a deuterated target to produce D-D fusion neutrons. The entire crystal and temperature system is mounted on a bellows which allows movement of the crystal along the beam axis and is completely contained on a single small vacuum flange. The modular crystal assembly permitted experimental flexibility. Operationally, flashover breakdowns along the side of the crystal and poor emitter tip characteristics can limit the neutron source. The experimental neutron results extend earlier published work by increasing the ion current and pulse length significantly to achieve a factor-of-two higher neutron output per thermal cycle. These findings are reviewed along with details of the instrument.

Tang, V; Meyer, G; Schmid, G; Spadaccini, C; Kerr, P; Rusnak, B; Sampayan, S; Naranjo, B; Putterman, S

2007-08-09T23:59:59.000Z

437

Laser Assisted Crystallization of Ferromagnetic Amorphous Ribbons...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Ferromagnetic Amorphous Ribbons: A Multimodal Characterization and Thermal Model Study. Laser Assisted Crystallization of Ferromagnetic Amorphous Ribbons: A Multimodal...

438

Ames Lab 101: Growing Crystals in Space  

SciTech Connect (OSTI)

Rohit Trivedi, distinguished professor of materials science and engineering, discusses his research with NASA to grow crystals in space.

Trivedi, Rohit

2011-01-01T23:59:59.000Z

439

Crystal of GTP Cyclohydrolase Type IB  

DOE Patents [OSTI]

This invention relates to a novel, bacterial GTP Cyclohydrolase Type IB enzyme, and the crystal structure thereof.

Swairjo, Manal A.; Iwata-Reuyl, Dirk; de Crecy-Lagard, Valerie

2012-12-11T23:59:59.000Z

440

Thermodynamically Stable Dispersions of Quantum Dots in a Nematic Liquid Crystal  

E-Print Network [OSTI]

*, State Scientific Institution "Institute for Single Crystals", NAS of Ukraine, 60, Lenin Ave., Kharkov, 61001, Ukraine Faculty of Pharmacy, UMR CNRS 7213, University of Strasbourg, Strasbourg, France § Institute of Physics, NAS of Ukraine, 46, Nauki Ave., Kiev, 03039, Ukraine North Carolina A&T State

Reznikov, Yuri

Note: This page contains sample records for the topic "out-perform single crystals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Isothermal and isochoric crystallization of highly hygroscopic pyridine N-oxide of aqueous solution  

Science Journals Connector (OSTI)

An oil-like aqueous solution of highly hygroscopic pyridine N-oxide (PNO) has been compressed in a diamond-anvil cell and single crystals of PNO have been grown under isothermal and isochoric conditions. The PNO anhydrate ambient-pressure structure is stabilized by CHO contacts up to 2 GPa at least.

Patyk, E.

2014-05-31T23:59:59.000Z

442

Heat Transfer Measurements for a Horizontal Micro-Tube Using Liquid Crystal Thermography  

E-Print Network [OSTI]

62 TC02-007 Heat Transfer Measurements for a Horizontal Micro-Tube Using Liquid Crystal-tube and 1000m micro-tube. In the single-phase heat transfer experiments, the fully-developed flow heat transfer were also measured using thermocouples (TC). The results showed that the heat transfer coefficient

Ghajar, Afshin J.

443

PHYSICAL REVIEW B 85, 094109 (2012) Electron dynamics of shocked polyethylene crystal  

E-Print Network [OSTI]

PHYSICAL REVIEW B 85, 094109 (2012) Electron dynamics of shocked polyethylene crystal Patrick L-dynamics simulations of the single shock Hugoniot are reported for a crystalline polyethylene (PE) model. The e. INTRODUCTION The material response of polyethylene (PE) to shock and its behavior in the warm dense matter (WDM

444

Robotic CCD microscope for enhanced crystal recognition  

DOE Patents [OSTI]

A robotic CCD microscope and procedures to automate crystal recognition. The robotic CCD microscope and procedures enables more accurate crystal recognition, leading to fewer false negative and fewer false positives, and enable detection of smaller crystals compared to other methods available today.

Segelke, Brent W. (San Ramon, CA); Toppani, Dominique (Livermore, CA)

2007-11-06T23:59:59.000Z

445

Single-Molecule Chemistry  

Science Journals Connector (OSTI)

With the currently available optical facilities, it is now possible to observe the dynamic behavior of single biomolecules and to study their kinetics. Within a group of molecules (e.g., in an enzyme), ... static...

2008-01-01T23:59:59.000Z

446

Microsoft Word - FEAA064O_ORNL_Welding Single Cystal_Factsheet_Rev01.doc  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Welding and Weld Repair of Single Crystal Gas Turbine Alloys Welding and Weld Repair of Single Crystal Gas Turbine Alloys (Oak Ridge National Laboratory) FACT SHEET I. PROJECT PARTICIPANTS A. Prime Participant: Oak Ridge National Laboratory (ORNL) B. Project Partners (no project funds to these partners): General Electric Corporation Siemens-Westinghouse Corporation Electric Power Research Institute (EPRI) PCC Airfoils Honeywell Aerospace Services Pratt and Whitney Corporation South Carolina Institute for Energy Studies II. PROJECT DESCRIPTION A. Objective It is the purpose of this project to investigate the potential for weld refurbishment and repair of single crystal gas turbine engine components and to determine processes, process conditions, and alloy compositions that will make such weld processing possible.

447

Transition from Irradiation-Induced Amorphization to Crystallization...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

from Irradiation-Induced Amorphization to Crystallization in Nanocrystalline Silicon Carbide. Transition from Irradiation-Induced Amorphization to Crystallization in...

448

Single Molecule as a Local Acoustic Detector for Mechanical Oscillators  

Science Journals Connector (OSTI)

A single molecule can serve as a nanometer-sized detector of acoustic strain. Such a nanomicrophone has the great advantage that it can be placed very close to acoustic signal sources and high sensitivities can be achieved. We demonstrate this scheme by monitoring the fluorescence intensity of a single dibenzoterrylene molecule in an anthracene crystal attached to an oscillating tuning fork. The characterization of the vibration amplitude and of the detection sensitivity is a first step towards detection and control of nanomechanical oscillators through optical detection and feedback.

Yuxi Tian; Pedro Navarro; Michel Orrit

2014-09-26T23:59:59.000Z

449

Bandwidth optimization of single-polarization single-mode photonic  

E-Print Network [OSTI]

is applied to optimize the cladding and core structures of SPSM photonic crystal fibers. We present several.L. Santos, F.M. Ara´ujo, and L.A. Ferreira. Optical sensing with photonic crystal fibers. Laser & Photonics cladding. Optics letters, 21(19):1547­1549, 1996. #12;11. M. Koshiba, S. Maruyama, and K. Hirayama

Freund, Robert M.

450

Structural phase transitions in low-dimensional ion crystals  

E-Print Network [OSTI]

A chain of singly-charged particles, confined by a harmonic potential, exhibits a sudden transition to a zigzag configuration when the radial potential reaches a critical value, depending on the particle number. This structural change is a phase transition of second order, whose order parameter is the crystal displacement from the chain axis. We study analytically the transition using Landau theory and find full agreement with numerical predictions by [J. Schiffer Phys. Rev. Lett. 70, 818 (1993)] and [Piacente et al Phys. Rev. B 69, 045324 (2004)]. Our theory allows us to determine analytically the system's behaviour at the transition point.

Shmuel Fishman; Gabriele De Chiara; Tommaso Calarco; Giovanna Morigi

2007-10-09T23:59:59.000Z

451

Structural phase transitions in low-dimensional ion crystals  

Science Journals Connector (OSTI)

A chain of singly charged particles, confined by a harmonic potential, exhibits a sudden transition to a zigzag configuration when the radial potential reaches a critical value, depending on the particle number. This structural change is a phase transition of second order, whose order parameter is the crystal displacement from the chain axis. We study analytically the transition using Landau theory and find full agreement with numerical predictions by Schiffer [Phys. Rev. Lett. 70, 818 (1993)] and Piacente et al. [Phys. Rev. B 69, 045324 (2004)]. Our theory allows us to determine analytically the system’s behavior at the transition point.

Shmuel Fishman; Gabriele De Chiara; Tommaso Calarco; Giovanna Morigi

2008-02-25T23:59:59.000Z

452

An ion trap built with photonic crystal fibre technology  

E-Print Network [OSTI]

We demonstrate a surface-electrode ion trap fabricated using techniques transferred from the manufacture of photonic-crystal fibres. This provides a relatively straightforward route for realizing traps with an electrode structure on the 100 micron scale with high optical access. We demonstrate the basic functionality of the trap by cooling a single ion to the quantum ground state, allowing us to measure a heating rate from the ground state of 787(24) quanta/s. Variation of the fabrication procedure used here may provide access to traps in this geometry with trap scales between 100 um and 10 um.

Lindenfelser, F; Kienzler, D; Bykov, D; Uebel, P; Schmidt, M A; Russell, P St J; Home, J P

2015-01-01T23:59:59.000Z

453

Retrieval of Cloud Phase and Ice Crystal Habit from Satellite Data  

SciTech Connect (OSTI)

Knowledge of cloud phase (liquid or ice) and crystal habit are of fundamental importance to both remote sensing and climate simulations. Using water droplets instead of ice crystals in retrieving cloud properties from satellite data can lead to errors in the retrieval of cloud height, optical thickness, and microphysical properties. Satellite retrievals of microphysical properties are also influenced by the crystal habit used in the retrieval, either indirectly via an assumed phase function or directly via assumed profiles of ice crystal habits. Realistic treatment of ice cloud radiative and microphysical properties, which depend on crystal habit, is important in climate simulations, especially in tropical anvil regions. In this work, we present a method for retrieving cloud phase and the dominant ice crystal habit from radiances measured by the Multi-angle Imaging Spectro-Radiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS). The shape of an atmospheric particle affects the scattering of light such that water droplets and ice crystals of various habits have somewhat different phase functions. Consequently the radiances measured by the MISR instrument, which observes light scattered from the same cloud at nine different viewing angles, are functions of the crystal shape. In principle, the measured angular radiance pattern can be used to infer the crystal shape. In this work, we present initial results from a cloud phase and ice crystal habit retrieval based on combining the MISR multi-angular visible wavelength measurements with MODIS shortwave infrared measurements. The nine angular measurements provided by the MISR cameras allow a wide range of scattering angles to be viewed in a single scene, which provides sensitivity to particle habit. The presence of the MODIS instrument on the same satellite allows additional information on particle size to be incorporated into the retrievals. Results of the retrieval method are presented for several case studies over the continental United States. Cloud phase can be determined from the MISR angular measurements alone, due to the large differences in the phase functions of water droplets and ice crystals. By combining the MISR and MODIS measurements, crystal habit, effective radius, and optical depth can be inferred simultaneously for ice clouds. Comparisons with ground-based retrieval methods and semi-coincident in situ data illustrate that the retrieved crystal habits and sizes are reasonable.

McFarlane, Sally A.; Marchand, Roger T.; Ackerman, Thomas P.

2004-07-19T23:59:59.000Z

454

Invisibility in PT-symmetric complex crystals  

E-Print Network [OSTI]

Bragg scattering in sinusoidal PT-symmetric complex crystals of finite thickness is theoretically investigated by the derivation of exact analytical expressions for reflection and transmission coefficients in terms of modified Bessel functions of first kind. The analytical results indicate that unidirectional invisibility, recently predicted for such crystals by coupled-mode theory [Z. Lin et al., Phys. Rev. Lett. 106, 213901 (2011)], breaks down for crystals containing a large number of unit cells. In particular, for a given modulation depth in a shallow sinusoidal potential, three regimes are encountered as the crystal thickness is increased. At short lengths the crystal is reflectionless and invisible when probed from one side (unidirectional invisibility), whereas at intermediate lengths the crystal remains reflectionless but not invisible; for longer crystals both unidirectional reflectionless and invisibility properties are broken.

Stefano Longhi

2011-11-15T23:59:59.000Z

455

Photonic crystals with controlled disorder  

SciTech Connect (OSTI)

Photonic crystals are extremely sensitive to structural disorder even to the point of completely losing their functionalities. While, on one side, this can be detrimental for applications in traditional optical devices, on the other side, it gives also rise to very interesting new physics and maybe even new applications. We propose a route to introduce disorder in photonic crystals in a controlled way by creating a certain percentage of vacancies in the lattice. We show how the method works and what type of materials can be obtained this way. Also, we use this system to probe the role of disorder on the resulting transport properties from various points of view, including measurements of the transport and scattering mean free path and the diffusion constant.

Garcia, P. D.; Sapienza, R.; Lopez, C. [Instituto de Ciencia de Materiales de Madrid (CSIC) and Unidad Asociada CSIC-UVigo, Cantoblanco E-28049, Madrid (Spain); Toninelli, C.; Wiersma, D. S. [European Laboratory for Nonlinear Spectroscopy and CNR-INO, 50019 Sesto Fiorentino, Florence (Italy)

2011-08-15T23:59:59.000Z

456

Neutron scattering investigation of the magnetic order in single crystalline BaFe2As2  

SciTech Connect (OSTI)

The magnetic structure of BaFe{sub 2}As{sub 2} was determined from polycrystalline neutron diffraction measurements soon after the ThCr{sub 2}Si{sub 2}-type FeAs-based superconductors were discovered. Both the moment direction and the in-plane antiferromagnetic wavevector are along the longer a-axis of the orthorhombic unit cell. There is only one combined magnetostructural transition at {approx}140 K. However, a later single-crystal neutron diffraction work reported contradicting results. Here, we show neutron diffraction results from a single-crystal sample, grown by a self-flux method, that support the original polycrystalline work.

Bao, Wei [Los Alamos National Laboratory; Qiu, Y [NIST; Kofu, M [UNIV OF VA; Lee, S - H [UNIV OF VA; Chang, S [NIST; Wu, T [HEFEI NAT. LAB.; Wu, G [HEFEI NAT. LAB; Chen, X H [HEFEI NAT. LAB

2008-01-01T23:59:59.000Z

457

Abstract crystals Department of Mathematics  

E-Print Network [OSTI]

is a normal crystal define a bijection si : B B by sib = ~f wti(b) i b, if wti(b) 0, ~e -wti(b) i b, if wti, b2 B2} with wti(b1 b2) = wti(b1) + wti(b2), i(b1 b2) = max{i(b1), i(b2) - wt(b1), i }, i(b1 b2

Ram, Arun

458

Dislocation-mediated melting of one-dimensional Rydberg crystals  

SciTech Connect (OSTI)

We consider cold Rydberg atoms in a one-dimensional optical lattice in the Mott regime with a single atom per site at zero temperature. An external laser drive with Rabi frequency {Omega} and laser detuning {Delta} creates Rydberg excitations whose dynamics is governed by an effective spin-chain model with (quasi) long-range interactions. This system possesses intrinsically a large degree of frustration resulting in a ground-state phase diagram in the ({Delta},{Omega}) plane with a rich topology. As a function of {Delta}, the Rydberg blockade effect gives rise to a series of crystalline phases commensurate with the optical lattice that form a so-called devil's staircase. The Rabi frequency {Omega}, on the other hand, creates quantum fluctuations that eventually lead to a quantum melting of the crystalline states. Upon increasing {Omega}, we find that generically a commensurate-incommensurate transition to a floating Rydberg crystal that supports gapless phonon excitations occurs first. For even larger {Omega}, dislocations within the floating Rydberg crystal start to proliferate and a second, Kosterlitz-Thouless-Nelson-Halperin-Young dislocation-mediated melting transition finally destroys the crystalline arrangement of Rydberg excitations. This latter melting transition is generic for one-dimensional Rydberg crystals and persists even in the absence of an optical lattice. The floating phase and the concomitant transitions can, in principle, be detected by Bragg scattering of light.

Sela, Eran; Garst, Markus [Institut fuer Theoretische Physik, Universitaet zu Koeln, Zuelpicher Str. 77, DE-50937 Koeln (Germany); Punk, Matthias [Physik Department, Technische Universitaet Muenchen, James-Franck-Strasse, DE-85748 Garching (Germany); Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

2011-08-15T23:59:59.000Z

459

Single-crystal Si formed on amorphous substrate at low temperature by nanopatterning and nickel-induced lateral crystallization  

E-Print Network [OSTI]

Engineering, Princeton University, Princeton, New Jersey 08544 Nan Yao and Henny Zandbergen Princeton Materials Institute, Princeton University, Princeton, New Jersey 08544 Jeffrey K. Farrer TSL/EDAX, Draper of thermally oxidized silicon wafer by low pressure chemical vapor deposition at 550 °C, followed by plasma

460

Single Particle Laser Ablation | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Single Particle Laser Ablation Single Particle Laser Ablation Leads No leads are available at this time. Effect of Solar Radiation on the Optical Properties and Molecular...

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461

Single-exciton nanocrystal laser  

DOE Patents [OSTI]

A laser system employing amplification via a single exciton regime and to optical gain media having single exciton amplification is provided.

Klimov, Victor I. (Los Alamos, NM); Ivanov, Sergei A. (Albuquerque, NM)

2012-01-17T23:59:59.000Z

462

Mixed-Ligand MetalOrganic Frameworks with Large Pores: Gas Sorption Properties and Single-Crystal-to-Single-Crystal Transformation on Guest  

E-Print Network [OSTI]

storage has been the center of interest because of the needs for an alternative fuel in mobile. The highest H2 gas uptake data reported so far is 7.5 wt% at 77 K and 70 bar in MOF-177,[23] but the best room temperature storage data are far less than 1% (0.62 wt%).[24] The highest CO2 uptake data reported so far

Paik Suh, Myunghyun

463

A proposal for the implementation of quantum gates with photonic-crystal coupled cavity waveguides  

E-Print Network [OSTI]

Quantum computers require technologies that offer both sufficient control over coherent quantum phenomena and minimal spurious interactions with the environment. We show, that photons confined to photonic crystals, and in particular to highly efficient waveguides formed from linear chains of defects doped with atoms can generate strong non-linear interactions which allow to implement both single and two qubit quantum gates. The simplicity of the gate switching mechanism, the experimental feasibility of fabricating two dimensional photonic crystal structures and integrability of this device with optoelectronics offers new interesting possibilities for optical quantum information processing networks.

Dimitris G. Angelakis; Marcelo Franca Santos; Vassilis Yannopapas; Artur Ekert

2007-04-12T23:59:59.000Z

464

Flowing Liquid Crystal Simulating the Schwarzschild Metric  

E-Print Network [OSTI]

We show how to simulate the equatorial section of the Schwarzschild metric through a flowing liquid crystal in its nematic phase. Inside a liquid crystal in the nematic phase, a traveling light ray feels an effective metric, whose properties are linked to perpendicular and parallel refractive indexes, $n_o$ e $n_e$ respectively, of the rod-like molecule of the liquid crystal. As these indexes depend on the scalar order parameter of the liquid crystal, the Beris-Edwards hydrodynamic theory is used to connect the order parameter with the velocity of a liquid crystal flow at each point. This way we calculate a radial velocity profile that simulates the equatorial section of the Schwarzschild metric, in the region outside of Schwarzschild's radius, in the nematic phase of the liquid crystal. In our model, the higher flow velocity can be of the order of some meters per second.

Erms R. Pereira; Fernando Moraes

2010-11-21T23:59:59.000Z

465

Phonon manipulation with phononic crystals.  

SciTech Connect (OSTI)

In this work, we demonstrated engineered modification of propagation of thermal phonons, i.e. at THz frequencies, using phononic crystals. This work combined theoretical work at Sandia National Laboratories, the University of New Mexico, the University of Colorado Boulder, and Carnegie Mellon University; the MESA fabrication facilities at Sandia; and the microfabrication facilities at UNM to produce world-leading control of phonon propagation in silicon at frequencies up to 3 THz. These efforts culminated in a dramatic reduction in the thermal conductivity of silicon using phononic crystals by a factor of almost 30 as compared with the bulk value, and about 6 as compared with an unpatterned slab of the same thickness. This work represents a revolutionary advance in the engineering of thermoelectric materials for optimal, high-ZT performance. We have demonstrated the significant reduction of the thermal conductivity of silicon using phononic crystal structuring using MEMS-compatible fabrication techniques and in a planar platform that is amenable to integration with typical microelectronic systems. The measured reduction in thermal conductivity as compared to bulk silicon was about a factor of 20 in the cross-plane direction [26], and a factor of 6 in the in-plane direction. Since the electrical conductivity was only reduced by a corresponding factor of about 3 due to the removal of conductive material (i.e., porosity), and the Seebeck coefficient should remain constant as an intrinsic material property, this corresponds to an effective enhancement in ZT by a factor of 2. Given the number of papers in literature devoted to only a small, incremental change in ZT, the ability to boost the ZT of a material by a factor of 2 simply by reducing thermal conductivity is groundbreaking. The results in this work were obtained using silicon, a material that has benefitted from enormous interest in the microelectronics industry and that has a fairly large thermoelectric power factor. In addition, the techniques and scientific understanding developed in the research can be applied to a wide range of materials, with the caveat that the thermal conductivity of such a material be dominated by phonon, rather than electron, transport. In particular, this includes several thermoelectric materials with attractive properties at elevated temperatures (i.e., greater than room temperature), such as silicon germanium and silicon carbide. It is reasonable that phononic crystal patterning could be used for high-temperature thermoelectric devices using such materials, with applications in energy scavenging via waste-heat recovery and thermoelectric cooling for high-performance microelectronic circuits. The only part of the ZT picture missing in this work was the experimental measurement of the Seebeck coefficient of our phononic crystal devices. While a first-order approximation indicates that the Seebeck coefficient should not change significantly from that of bulk silicon, we were not able to actually verify this assumption within the timeframe of the project. Additionally, with regards to future high-temperature applications of this technology, we plan to measure the thermal conductivity reduction factor of our phononic crystals as elevated temperatures to confirm that it does not diminish, given that the nominal thermal conductivity of most semiconductors, including silicon, decreases with temperature above room temperature. We hope to have the opportunity to address these concerns and further advance the state-of-the-art of thermoelectric materials in future projects.

Kim Bongsang; Hopkins, Patrick Edward; Leseman, Zayd C.; Goettler, Drew F.; Su, Mehmet F. (University of New Mexico, Albuquerque, NM); El-Kady, Ihab Fathy; Reinke, Charles M.; Olsson, Roy H., III

2012-01-01T23:59:59.000Z

466

Crystallization of niobium germanosilicate glasses  

SciTech Connect (OSTI)

Niobium germanosilicate glasses are potential candidates for the fabrication of transparent glass ceramics with interesting non-linear optical properties. A series of glasses in the (Ge,Si)O{sub 2}-Nb{sub 2}O{sub 5}-K{sub 2}O system were prepared by melting and casting and their characteristic temperatures were determined by differential thermal analysis. Progressive replacement of GeO{sub 2} by SiO{sub 2} improved the thermal stability of the glasses. Depending on the composition and the crystallization heat-treatment, different nanocrystalline phases-KNbSi{sub 2}O{sub 7}, K{sub 3}Nb{sub 3}Si{sub 2}O{sub 13} and K{sub 3.8}Nb{sub 5}Ge{sub 3}O{sub 20.4} could be obtained. The identification and characterization of these phases were performed by X-ray diffraction and Raman spectroscopy. The 40 GeO{sub 2}-10 SiO{sub 2}-25 Nb{sub 2}O{sub 5}-25 K{sub 2}O (mol%) composition presented the higher ability for volume crystallization and its nucleation temperature was determined by the Marotta's method. An activation energy for crystal growth of {approx}529 kJ/mol and a nucleation rate of 9.7x10{sup 18} m{sup -3} s{sup -1} was obtained, for this composition. Transparent glass ceramics with a crystalline volume fraction of {approx}57% were obtained after a 2 h heat-treatment at the nucleation temperature, with crystallite sizes of {approx}20 nm as determined by transmission electron microscopy. - Abstract: TEM image and XRD pattern of the glass ceramic produced (circles indicate nanocrystals).

Santos, Rodrigo [Departamento de Engenharia de Materiais/ICEMS, Instituto Superior Tecnico/TU Lisbon, Av. Rovisco Pais, 1, 1049-001 Lisbon (Portugal); Santos, Luis F., E-mail: luis.santos@ist.utl.p [Departamento de Engenharia de Materiais/ICEMS, Instituto Superior Tecnico/TU Lisbon, Av. Rovisco Pais, 1, 1049-001 Lisbon (Portugal); Almeida, Rui M. [Departamento de Engenharia de Materiais/ICEMS, Instituto Superior Tecnico/TU Lisbon, Av. Rovisco Pais, 1, 1049-001 Lisbon (Portugal); Deubener, Joachim [Institute of Non-Metallic Materials, Clausthal University of Technology, Clausthal-Zellerfeld (Germany); Wondraczek, Lothar [Department of Materials Science, Glass and Ceramics, University of Erlangen-Nuremberg, 91058 Erlangen (Germany)

2010-01-15T23:59:59.000Z

467

Crystal Structure of the Response Regulator 02 Receiver Domain, the Essential YycF Two-Component System of Streptococcus pneumoniae in both Complexed and Native States  

Science Journals Connector (OSTI)

...SAD method from a single crystal of a xenon derivative of RR02rec. The electron density...92 30.86-2.34 40.16-1.85 Oscillation () 1.0 1.0 1.0 1.0 No. of measurements...single-wavelength anomalous diffraction (xenon SAD), and 1.85 A and a third structure...

Colin J. Bent; Neil W. Isaacs; Timothy J. Mitchell; Alan Riboldi-Tunnicliffe

2004-05-01T23:59:59.000Z

468

Journal of Crystal Growth 250 (2003) 499515 Induction time in crystallization of gas hydrates  

E-Print Network [OSTI]

for revealing how additives in the solution that act as kinetic inhibitors of hydrate crystallization can affect to prevent hydrate crystallization. These options include heating, insulation, water removal, and the use

Firoozabadi, Abbas

469

Using textons to rank crystallization droplets by the likely presence of crystals  

Science Journals Connector (OSTI)

A robust and transferable algorithm is presented to objectively describe and rank robotically captured images of crystallization droplets according to their likelihood of crystalline behaviour for the efficient and accurate identification of successful crystallization.

Ng, J.T.

2014-09-27T23:59:59.000Z

470

Crystal structure and interaction dependence of the crystal-melt interfacial free energy  

E-Print Network [OSTI]

We examine via molecular simulation the dependence of the crystal-melt interfacial free energy gamma on molecular interaction and crystal structure (fcc vs bcc) for systems interacting with inverse-power repulsive potentials, ...

Davidchack, R. L.; Laird, Brian Bostian

2005-03-01T23:59:59.000Z

471

Antimony Induced Crystallization of Amorphous Silicon  

Science Journals Connector (OSTI)

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1?m were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.

Y. Wang; H.Z. Li; C.N. Yu; G.M. Wu; I. Gordon; P. Schattschneider; O. Van Der Biest

2007-01-01T23:59:59.000Z