Sample records for atoms wide grown

  1. INTERNATIONAL ACTIVITIES Preamble: Beans (Phaseolus vulgaris) originated in Latin America and are widely grown at

    E-Print Network [OSTI]

    INTERNATIONAL ACTIVITIES Preamble: Beans (Phaseolus vulgaris) originated in Latin America and are widely grown at mid- to higher elevations today from Chile to Canada. Brazil is the world's leading bean their importance as a food security crop in many Latin American countries, bean production has been relegated

  2. Two wide-angle imaging neutral-atom spectrometers

    SciTech Connect (OSTI)

    McComas, D.J.

    1997-12-31T23:59:59.000Z

    The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission provides a new capability for stereoscopically imaging the magnetosphere. By imaging the charge exchange neutral atoms over a broad energy range (1 < E , {approximately} 100 keV) using two identical instruments on two widely-spaced high-altitude, high-inclination spacecraft, TWINS will enable the 3-dimensional visualization and the resolution of large scale structures and dynamics within the magnetosphere for the first time. These observations will provide a leap ahead in the understanding of the global aspects of the terrestrial magnetosphere and directly address a number of critical issues in the ``Sun-Earth Connections`` science theme of the NASA Office of Space Science.

  3. Surface diffusion coefficient of Au atoms on single layer graphene grown on Cu

    SciTech Connect (OSTI)

    Ruffino, F., E-mail: francesco.ruffino@ct.infn.it; Cacciato, G.; Grimaldi, M. G. [Dipartimento di Fisica ed Astronomia-Universitá di Catania, via S. Sofia 64, 95123 Catania, Italy and MATIS IMM-CNR, via S. Sofia 64, 95123 Catania (Italy)

    2014-02-28T23:59:59.000Z

    A 5?nm thick Au film was deposited on single layer graphene sheets grown on Cu. By thermal processes, the dewetting phenomenon of the Au film on the graphene was induced so to form Au nanoparticles. The mean radius, surface-to-surface distance, and surface density evolution of the nanoparticles on the graphene sheets as a function of the annealing temperature were quantified by scanning electron microscopy analyses. These quantitative data were analyzed within the classical mean-field nucleation theory so to obtain the temperature-dependent Au atoms surface diffusion coefficient on graphene: D{sub S}(T)=[(8.2±0.6)×10{sup ?8}]exp[?(0.31±0.02(eV)/(at) )/kT]?cm{sup 2}/s.

  4. Atomic-Scale Investigation of Epitaxial Graphene Grown on 6H-SiC(0001) Using Scanning Tunneling Microscopy and Spectroscopy

    E-Print Network [OSTI]

    Kim, Sehun

    Atomic-Scale Investigation of Epitaxial Graphene Grown on 6H-SiC(0001) Using Scanning Tunneling ReceiVed: June 26, 2010 Graphene was epitaxially grown on a 6H-SiC(0001) substrate by thermal the evolution of the graphene growth as a function of the temperature. We found that the evaporation of Si

  5. Channelization architecture for wide-band slow light in atomic vapors

    E-Print Network [OSTI]

    Zachary Dutton; Mark Bashkansky; Michael Steiner; John Reintjes

    2005-10-20T23:59:59.000Z

    We propose a ``channelization'' architecture to achieve wide-band electromagnetically induced transparency (EIT) and ultra-slow light propagation in atomic Rb-87 vapors. EIT and slow light are achieved by shining a strong, resonant ``pump'' laser on the atomic medium, which allows slow and unattenuated propagation of a weaker ``signal'' beam, but only when a two-photon resonance condition is satisfied. Our wideband architecture is accomplished by dispersing a wideband signal spatially, transverse to the propagation direction, prior to entering the atomic cell. When particular Zeeman sub-levels are used in the EIT system, then one can introduce a magnetic field with a linear gradient such that the two-photon resonance condition is satisfied for each individual frequency component. Because slow light is a group velocity effect, utilizing differential phase shifts across the spectrum of a light pulse, one must then introduce a slight mismatch from perfect resonance to induce a delay. We present a model which accounts for diffusion of the atoms in the varying magnetic field as well as interaction with levels outside the ideal three-level system on which EIT is based. We find the maximum delay-bandwidth product decreases with bandwidth, and that delay-bandwidth product ~1 should be achievable with bandwidth ~50 MHz (~5 ns delay). This is a large improvement over the ~1 MHz bandwidths in conventional slow light systems and could be of use in signal processing applications.

  6. Tunneling spectroscopy of superconducting MoN and NbTiN grown by atomic layer deposition

    SciTech Connect (OSTI)

    Groll, Nickolas R., E-mail: ngroll@anl.gov; Klug, Jeffrey A.; Claus, Helmut; Pellin, Michael J.; Proslier, Thomas, E-mail: proslier@anl.gov [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Cao, Chaoyue; Becker, Nicholas G.; Zasadzinski, John F. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Altin, Serdar [Fen Edebiyat Fakultesi, Fizik Bolumu, Inonu Universitesi, 44280 Malatya (Turkey)

    2014-03-03T23:59:59.000Z

    A tunneling spectroscopy study is presented of superconducting MoN and Nb{sub 0.8}Ti{sub 0.2}N thin films grown by atomic layer deposition (ALD). The films exhibited a superconducting gap of 2?meV and 2.4?meV, respectively, with a corresponding critical temperature of 11.5?K and 13.4?K, among the highest reported T{sub c} values achieved by the ALD technique. Tunnel junctions were obtained using a mechanical contact method with a Au tip. While the native oxides of these films provided poor tunnel barriers, high quality tunnel junctions with low zero bias conductance (below ?10%) were obtained using an artificial tunnel barrier of Al{sub 2}O{sub 3} on the film's surface grown ex situ by ALD. We find a large critical current density on the order of 4?×?10{sup 6}?A/cm{sup 2} at T?=?0.8T{sub c} for a 60?nm MoN film and demonstrate conformal coating capabilities of ALD onto high aspect ratio geometries. These results suggest that the ALD technique offers significant promise for thin film superconducting device applications.

  7. Density dependence of the room temperature thermal conductivity of atomic layer deposition-grown amorphous alumina (Al{sub 2}O{sub 3})

    SciTech Connect (OSTI)

    Gorham, Caroline S.; Gaskins, John T.; Hopkins, Patrick E., E-mail: phopkins@virginia.edu [Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Parsons, Gregory N.; Losego, Mark D. [Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2014-06-23T23:59:59.000Z

    We report on the thermal conductivity of atomic layer deposition-grown amorphous alumina thin films as a function of atomic density. Using time domain thermoreflectance, we measure the thermal conductivity of the thin alumina films at room temperature. The thermal conductivities vary ?35% for a nearly 15% change in atomic density and are substrate independent. No density dependence of the longitudinal sound speeds is observed with picosecond acoustics. The density dependence of the thermal conductivity agrees well with a minimum limit to thermal conductivity model that is modified with a differential effective-medium approximation.

  8. Investigation of MOVPE-grown GaN layers doped with As atoms A. F. Tsatsul'nikov, B. Ya. Ber, A. P. Kartashova, Yu. A. Kudryavtsev, N. N. Ledentsov,

    E-Print Network [OSTI]

    Nabben, Reinhard

    Investigation of MOVPE-grown GaN layers doped with As atoms A. F. Tsatsul'nikov, B. Ya. Ber, A. P vapor-phase epitaxy. It is shown that the deposition of GaAs on a GaN surface relieves stresses in the GaN layer. The high-temperature overgrowth of a thin GaAs layer by a GaN layer causes As atoms

  9. Accurate small and wide angle x-ray scattering profiles from atomic models of proteins and nucleic acids

    SciTech Connect (OSTI)

    Nguyen, Hung T. [BioMaPS Institute for Quantitative Biology, Rutgers University, Piscataway, New Jersey 08854 (United States); Pabit, Suzette A.; Meisburger, Steve P.; Pollack, Lois [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Case, David A., E-mail: case@biomaps.rutgers.edu [BioMaPS Institute for Quantitative Biology, Rutgers University, Piscataway, New Jersey 08854 (United States); Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854 (United States)

    2014-12-14T23:59:59.000Z

    A new method is introduced to compute X-ray solution scattering profiles from atomic models of macromolecules. The three-dimensional version of the Reference Interaction Site Model (RISM) from liquid-state statistical mechanics is employed to compute the solvent distribution around the solute, including both water and ions. X-ray scattering profiles are computed from this distribution together with the solute geometry. We describe an efficient procedure for performing this calculation employing a Lebedev grid for the angular averaging. The intensity profiles (which involve no adjustable parameters) match experiment and molecular dynamics simulations up to wide angle for two proteins (lysozyme and myoglobin) in water, as well as the small-angle profiles for a dozen biomolecules taken from the BioIsis.net database. The RISM model is especially well-suited for studies of nucleic acids in salt solution. Use of fiber-diffraction models for the structure of duplex DNA in solution yields close agreement with the observed scattering profiles in both the small and wide angle scattering (SAXS and WAXS) regimes. In addition, computed profiles of anomalous SAXS signals (for Rb{sup +} and Sr{sup 2+}) emphasize the ionic contribution to scattering and are in reasonable agreement with experiment. In cases where an absolute calibration of the experimental data at q = 0 is available, one can extract a count of the excess number of waters and ions; computed values depend on the closure that is assumed in the solution of the Ornstein–Zernike equations, with results from the Kovalenko–Hirata closure being closest to experiment for the cases studied here.

  10. Energy band alignment of atomic layer deposited HfO{sub 2} on epitaxial (110)Ge grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Hudait, M. K.; Zhu, Y. [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Maurya, D.; Priya, S. [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)

    2013-03-04T23:59:59.000Z

    The band alignment properties of atomic layer HfO{sub 2} film deposited on epitaxial (110)Ge, grown by molecular beam epitaxy, was investigated using x-ray photoelectron spectroscopy. The cross-sectional transmission electron microscopy exhibited a sharp interface between the (110)Ge epilayer and the HfO{sub 2} film. The measured valence band offset value of HfO{sub 2} relative to (110)Ge was 2.28 {+-} 0.05 eV. The extracted conduction band offset value was 2.66 {+-} 0.1 eV using the bandgaps of HfO{sub 2} of 5.61 eV and Ge bandgap of 0.67 eV. These band offset parameters and the interface chemical properties of HfO{sub 2}/(110)Ge system are of tremendous importance for the design of future high hole mobility and low-power Ge-based metal-oxide transistor devices.

  11. Impact of surface morphology of Si substrate on performance of Si/ZnO heterojunction devices grown by atomic layer deposition technique

    SciTech Connect (OSTI)

    Hazra, Purnima; Singh, Satyendra Kumar [Department of Electronics and Communication Engineering, Motilal Neheru National Institute of Technology, Allahabad 211004 (India); Jit, Satyabrata, E-mail: sjit.ece@itbhu.ac.in [Department of Electronics Engineering, Indian Institute of Technology (BHU), Varanasi 221005 (India)

    2015-01-01T23:59:59.000Z

    In this paper, the authors have investigated the structural, optical, and electrical characteristics of silicon nanowire (SiNW)/zinc oxide (ZnO) core–shell nanostructure heterojunctions and compared their characteristics with Si/ZnO planar heterojunctions to investigate the effect of surface morphology of Si substrate in the characteristics of Si/ZnO heterojunction devices. In this work, ZnO thin film was conformally deposited on both p-type ?100? planar Si substrate and substrate with vertically aligned SiNW arrays by atomic layer deposition (ALD) method. The x-ray diffraction spectra show that the crystalline structures of Si/ZnO heterojunctions are having (101) preferred orientation, whereas vertically oriented SiNW/ZnO core–shell heterojunctions are having (002)-oriented wurtzite crystalline structures. The photoluminescence (PL) spectra of Si/ZnO heterojunctions show a very sharp single peak at 377?nm, corresponding to the bandgap of ZnO material with no other defect peaks in visible region; hence, these devices can have applications only in UV region. On the other hand, SiNW/ZnO heterojunctions are having band-edge peak at 378?nm along with a broad emission band, spreading almost throughout the entire visible region with a peak around 550?nm. Therefore, ALD-grown SiNW/ZnO heterojunctions can emit green and red light simultaneously. Reflectivity measurement of the heterojunctions further confirms the enhancement of visible region peak in the PL spectra of SiNW/ZnO heterojunctions, as the surface of the SiNW/ZnO heterojunctions exhibits extremely low reflectance (<3%) in the visible wavelength region compared to Si/ZnO heterojunctions (>20%). The current–voltage characteristics of both Si/ZnO and SiNW/ZnO heterojunctions are measured with large area ohmic contacts on top and bottom of the structure to compare the electrical characteristics of the devices. Due to large surface to-volume ratio of SiNW/ZnO core–shell heterojunction devices, the output current rating is about 130 times larger compared to their planar version at 2 V forward bias voltage. This higher output current rating can be exploited for fabricating high-performance nanoelectronic and optoelectronic devices in near future.

  12. On the reliability of nanoindentation hardness of Al{sub 2}O{sub 3} films grown on Si-wafer by atomic layer deposition

    SciTech Connect (OSTI)

    Liu, Xuwen, E-mail: xuwen.liu@aalto.fi; Haimi, Eero; Hannula, Simo-Pekka [Department of Materials Science and Engineering, Aalto University School of Chemical Technology, Vuorimiehentie 2A, FI-00076 Espoo (Finland); Ylivaara, Oili M. E.; Puurunen, Riikka L. [VTT Technical Research Centre of Finland, Tietotie 3, FI-02044 Espoo (Finland)

    2014-01-15T23:59:59.000Z

    The interest in applying thin films on Si-wafer substrate for microelectromechanical systems devices by using atomic layer deposition (ALD) has raised the demand on reliable mechanical property data of the films. This study aims to find a quick method for obtaining nanoindentation hardness of thin films on silicon with improved reliability. This is achieved by ensuring that the film hardness is determined under the condition that no plastic deformation occurs in the substrate. In the study, ALD Al{sub 2}O{sub 3} films having thickness varying from 10 to 600?nm were deposited on a single-side polished silicon wafer at 300?°C. A sharp cube-corner indenter was used for the nanoindentation measurements. A thorough study on the Si-wafer reference revealed that at a specific contact depth of about 8?nm the wafer deformation in loading transferred from elastic to elastic–plastic state. Furthermore, the occurrence of this transition was associated with a sharp increase of the power-law exponent, m, when the unloading data were fitted to a power-law relation. Since m is only slightly material dependent and should fall between 1.2 and 1.6 for different indenter geometry having elastic contact to common materials, it is proposed that the high m values are the results from the inelastic events during unloading. This inelasticity is linked to phase transformations during pressure releasing, a unique phenomenon widely observed in single crystal silicon. Therefore, it is concluded that m could be used to monitor the mechanical state of the Si substrate when the whole coating system is loaded. A suggested indentation depth range can then be assigned to each film thickness to provide guidelines for obtaining reliable property data. The results show good consistence for films thicker than 20?nm and the nanoindentation hardness is about 11?GPa independent of film thickness.

  13. Influence of ion-to-atom ratio on the microstructure of evaporated molybdenum thin films grown using low energy argon ions

    SciTech Connect (OSTI)

    Yadav, Praveen Kumar, E-mail: praveenyadav@rrcat.gov.in; Nayak, Maheswar; Rai, Sanjay Kumar; Lodha, Gyanendra Singh [X-ray Optics Section, Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Sant, Tushar; Sharma, Surinder Mohan [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Mukherjee, Chandrachur [Mechanical and Optical Support Section, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

    2014-03-15T23:59:59.000Z

    The authors report the effect of argon ion to molybdenum atom ratio (r) on the microstructure of low energy (70?eV) argon ion assisted electron beam evaporated Mo thin films. Surface roughness, morphology, and crystallinity of Mo films are found to strongly depend on “r.” Increase of “r” from 0 to 100 induces gradual loss in crystallinity, reduction in surface roughness and systematic increase in density of the film. For “r”???100, average atomic density of the film approaches the bulk value (97%) with lowest surface roughness. Further, increasing “r” up to 170 reduces the atomic density, increases roughness, and increase in crystallinity induced by low energy Ar ion beam. The observed surface roughness and grain size determined by x-ray reflectivity and glancing incidence x-ray diffraction correlate well with atomic force microscopy measurements. This study demonstrates that for r?=?100 one gets lowest roughness Mo film with highest density and nearly amorphous microstructure. The growth model is discussed by structural zone model.

  14. Effects of substrate temperature, substrate orientation, and energetic atomic collisions on the structure of GaN films grown by reactive sputtering

    SciTech Connect (OSTI)

    Schiaber, Ziani S.; Lisboa-Filho, Paulo N.; Silva, José H. D. da [Universidade Estadual Paulista, UNESP, Bauru, São Paulo 17033-360 (Brazil)] [Universidade Estadual Paulista, UNESP, Bauru, São Paulo 17033-360 (Brazil); Leite, Douglas M. G. [Universidade Federal de Itajubá, UNIFEI, Itajubá, Minas Gerais 37500-903 (Brazil)] [Universidade Federal de Itajubá, UNIFEI, Itajubá, Minas Gerais 37500-903 (Brazil); Bortoleto, José R. R. [Universidade Estadual Paulista, UNESP, Sorocaba, São Paulo 18087-180 (Brazil)] [Universidade Estadual Paulista, UNESP, Sorocaba, São Paulo 18087-180 (Brazil)

    2013-11-14T23:59:59.000Z

    The combined effects of substrate temperature, substrate orientation, and energetic particle impingement on the structure of GaN films grown by reactive radio-frequency magnetron sputtering are investigated. Monte-Carlo based simulations are employed to analyze the energies of the species generated in the plasma and colliding with the growing surface. Polycrystalline films grown at temperatures ranging from 500 to 1000 °C clearly showed a dependence of orientation texture and surface morphology on substrate orientation (c- and a-plane sapphire) in which the (0001) GaN planes were parallel to the substrate surface. A large increase in interplanar spacing associated with the increase in both a- and c-parameters of the hexagonal lattice and a redshift of the optical bandgap were observed at substrate temperatures higher than 600 °C. The results showed that the tensile stresses produced during the film's growth in high-temperature deposition ranges were much larger than the expected compressive stresses caused by the difference in the thermal expansion coefficients of the film and substrate in the cool-down process after the film growth. The best films were deposited at 500 °C, 30 W and 600 °C, 45 W, which corresponds to conditions where the out diffusion from the film is low. Under these conditions the benefits of the temperature increase because of the decrease in defect density are greater than the problems caused by the strongly strained lattice that occurr at higher temperatures. The results are useful to the analysis of the growth conditions of GaN films by reactive sputtering.

  15. Laser damage properties of TiO{sub 2}/Al{sub 2}O{sub 3} thin films grown by atomic layer deposition

    SciTech Connect (OSTI)

    Wei Yaowei; Liu Hao; Sheng Ouyang; Liu Zhichao; Chen Songlin; Yang Liming

    2011-08-20T23:59:59.000Z

    Research on thin film deposited by atomic layer deposition (ALD) for laser damage resistance is rare. In this paper, it has been used to deposit TiO{sub 2}/Al{sub 2}O{sub 3} films at 110 deg. C and 280 deg. C on fused silica and BK7 substrates. Microstructure of the thin films was investigated by x-ray diffraction. The laser-induced damage threshold (LIDT) of samples was measured by a damage test system. Damage morphology was studied under a Nomarski differential interference contrast microscope and further checked under an atomic force microscope. Multilayers deposited at different temperatures were compared. The results show that the films deposited by ALD had better uniformity and transmission; in this paper, the uniformity is better than 99% over 100 mm {Phi} samples, and the transmission is more than 99.8% at 1064 nm. Deposition temperature affects the deposition rate and the thin film microstructure and further influences the LIDT of the thin films. As to the TiO{sub 2}/Al{sub 2}O{sub 3} films, the LIDTs were 6.73{+-}0.47 J/cm{sup 2} and 6.5{+-}0.46 J/cm{sup 2} at 110 deg. C on fused silica and BK7 substrates, respectively. The LIDTs at 110 deg. C are notably better than 280 deg. C.

  16. Optical method of atomic ordering estimation

    SciTech Connect (OSTI)

    Prutskij, T. [Instituto de Ciencias, BUAP, Privada 17 Norte, No 3417, col. San Miguel Huyeotlipan, Puebla, Pue. (Mexico); Attolini, G. [IMEM/CNR, Parco Area delle Scienze 37/A - 43010, Parma (Italy); Lantratov, V.; Kalyuzhnyy, N. [Ioffe Physico-Technical Institute, 26 Polytekhnicheskaya, St Petersburg 194021, Russian Federation (Russian Federation)

    2013-12-04T23:59:59.000Z

    It is well known that within metal-organic vapor-phase epitaxy (MOVPE) grown semiconductor III-V ternary alloys atomically ordered regions are spontaneously formed during the epitaxial growth. This ordering leads to bandgap reduction and to valence bands splitting, and therefore to anisotropy of the photoluminescence (PL) emission polarization. The same phenomenon occurs within quaternary semiconductor alloys. While the ordering in ternary alloys is widely studied, for quaternaries there have been only a few detailed experimental studies of it, probably because of the absence of appropriate methods of its detection. Here we propose an optical method to reveal atomic ordering within quaternary alloys by measuring the PL emission polarization.

  17. Thermal conductivity of Er{sup +3}:Y{sub 2}O{sub 3} films grown by atomic layer deposition

    SciTech Connect (OSTI)

    Raeisi Fard, Hafez; Hess, Andrew; Pashayi, Kamyar; Borca-Tasciuc, Theodorian, E-mail: borcat@rpi.edu [Mechanical, Aerospace and Nuclear Engineering Department, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)] [Mechanical, Aerospace and Nuclear Engineering Department, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Becker, Nicholas; Proslier, Thomas; Pellin, Michael [Material Sciences Division, Argonne National Laboratory 9700 S. Cass Avenue, Lemont, Illinois 60439 (United States)] [Material Sciences Division, Argonne National Laboratory 9700 S. Cass Avenue, Lemont, Illinois 60439 (United States)

    2013-11-04T23:59:59.000Z

    Cross-plane thermal conductivity of 800, 458, and 110?nm erbium-doped crystalline yttria (Er{sup +3}:Y{sub 2}O{sub 3}) films deposited via atomic layer deposition was measured using the 3? method at room temperature. Thermal conductivity results show 16-fold increase in thermal conductivity from 0.49?W m{sup ?1}K{sup ?1} to 8?W m{sup ?1}K{sup ?1} upon post deposition annealing, partially due to the suppression of the number of the -OH/H{sub 2}O bonds in the films after annealing. Thermal conductivity of the annealed film was ?70% lower than undoped bulk single crystal yttria. The cumulative interface thermal resistivity of substrate-Er{sup +3}:Y{sub 2}O{sub 3}-metal heater was determined to be ?2.5?×?10{sup ?8} m{sup 2} K/W.

  18. Influence of dosing sequence and film thickness on structure and resistivity of Al-ZnO films grown by atomic layer deposition

    SciTech Connect (OSTI)

    Pollock, Evan B., E-mail: ebpollock@gmail.com; Lad, Robert J. [Laboratory for Surface Science and Technology, University of Maine, 5708 ESRB-Barrows Hall, Orono, Maine 04469 (United States)

    2014-07-01T23:59:59.000Z

    Aluminum-doped zinc oxide (AZO) films were deposited onto amorphous silica substrates using an atomic layer deposition process with diethyl zinc (DEZ), trimethyl aluminum (TMA), and deionized water at 200?°C. Three different Al doping sequences were used at a ZnO:Al ratio of 11:1 within the films. A minimum film resistivity of 1.6?×?10{sup ?3}?? cm was produced using sequential dosing of DEZ, TMA, DEZ, followed by H{sub 2}O for the Al doping step. This “ZAZW” sequence yielded an AZO film resistivity that is independent of film thickness, crystallographic texture, and grain size, as determined by high resolution x-ray diffraction (XRD). A pseudo-Voigt analysis method yields values for grain sizes that are smaller than those calculated using other XRD methods. Anisotropic grain sizes or variations in crystallographic texture have minimal influence on film resistivity, which suggests that factors other than film texture, such as intragrain scattering, may be important in influencing film resistivity.

  19. Design of a self-aligned, wide temperature range (300 mK-300 K) atomic force microscope/magnetic force microscope with 10 nm magnetic force microscope resolution

    SciTech Connect (OSTI)

    Karc?, Özgür [NanoMagnetics Instruments Ltd., Hacettepe - ?vedik OSB Teknokent, 1368. Cad., No: 61/33, 06370, Yenimahalle, Ankara (Turkey); Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey); Dede, Münir [NanoMagnetics Instruments Ltd., Hacettepe - ?vedik OSB Teknokent, 1368. Cad., No: 61/33, 06370, Yenimahalle, Ankara (Turkey); Oral, Ahmet, E-mail: orahmet@metu.edu.tr [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey)

    2014-10-15T23:59:59.000Z

    We describe the design of a wide temperature range (300 mK-300 K) atomic force microscope/magnetic force microscope with a self-aligned fibre-cantilever mechanism. An alignment chip with alignment groves and a special mechanical design are used to eliminate tedious and time consuming fibre-cantilever alignment procedure for the entire temperature range. A low noise, Michelson fibre interferometer was integrated into the system for measuring deflection of the cantilever. The spectral noise density of the system was measured to be ?12 fm/?Hz at 4.2 K at 3 mW incident optical power. Abrikosov vortices in BSCCO(2212) single crystal sample and a high density hard disk sample were imaged at 10 nm resolution to demonstrate the performance of the system.

  20. Direct imaging of InSb (110)-(1x1) surface grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Mishima, T. D. [Homer L. Dodge Department of Physics and Astronomy, and Center for Semiconductor Physics in Nanostructures, University of Oklahoma, Norman, Oklahoma 73019 (United States)

    2011-10-01T23:59:59.000Z

    High-resolution transmission electron microscopy under a profile imaging condition (HR-profile TEM) was employed to determine the structural model for the InSb(110)-(1x1) relaxation surface grown by molecular beam epitaxy (MBE). HR-profile TEM analyses indicate that the chevron model, which is widely accepted for zinc-blende-type III-V(110)-(1x1) surfaces prepared by cleavage, is also applicable to the InSb(110)-(1x1) surface prepared under an Sb-rich MBE condition. The assignment of atomic species (In or Sb) of InSb(110)-(1x1) surfaces was confirmed based on a HR-profile TEM image that captures the connected facets of InSb(110)-(1x1) and InSb(111)B-(2x2). On the basis of the well-known atomic species of InSb(111)B-(2x2), the atomic species of the InSb(110)-(1x1) surface were deduced straightforwardly: the atoms shifted upward and downward at the topmost layer of the InSb(110)-(1x1) surface are Sb and In, respectively. The atomic arrangements of the InSb(110)-(1x1)-InSb(111)B-(2x2) facet determined by HR-profile TEM may represent the atomic arrangements of zinc-blende-type III-V(331)B surfaces.

  1. Effects of 1 MeV Electron Beam Irradiation on Multilayer Graphene Grown on 6H-SiC(0001)

    E-Print Network [OSTI]

    Kim, Sehun

    Effects of 1 MeV Electron Beam Irradiation on Multilayer Graphene Grown on 6H-SiC(0001) Ki-359, Korea ReceiVed: June 11, 2008; ReVised Manuscript ReceiVed: July 14, 2008 Graphene layers grown on 6H of the graphene layer. Since Geim and his co-workers1 extracted individual ultrathin sheets of carbon atoms

  2. Atomic 'mismatch' creates nano 'dumbbells' | Argonne National...

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

    Atomic 'mismatch' creates nano 'dumbbells' By Jared Sagoff * December 4, 2014 Tweet EmailPrint ARGONNE, Ill. - Like snowflakes, nanoparticles come in a wide variety of shapes and...

  3. Wide Blue Sky

    E-Print Network [OSTI]

    Collins, Caroline Imani

    2011-01-01T23:59:59.000Z

    dressed neatly in a dark blue dress, its high neck trimmedIt was covered in a light blue fabric embellished with softOF CALIFORNIA RIVERSIDE Wide Blue Sky A Thesis submitted in

  4. Atom-light interactions in ultracold anisotropic media

    E-Print Network [OSTI]

    Vengalattore, Mukund T., 1977-

    2005-01-01T23:59:59.000Z

    A series of studies on atom-light interactions in ultracold anisotropic media were conducted. Methods to trap ultracold neutral atoms in novel traps with widely tunable trap frequencies and anisotropies were investigated. ...

  5. Wide Angle Compton Scattering

    E-Print Network [OSTI]

    Rainer Jakob

    2000-10-16T23:59:59.000Z

    We present the handbag contribution to Wide Angle Compton Scattering (WACS) at moderately large momentum transfer obtained with a proton distribution amplitude close to the asymptotic form. In comparison it is found to be significantly larger than results from the hard scattering (pQCD) approach.

  6. Bi-Sr-Ca-Cu-O thin films grown by flash evaporation and pulsed laser deposition 

    E-Print Network [OSTI]

    Ganapathy Subramanian, Santhana

    2004-09-30T23:59:59.000Z

    . Thin films were grown by flash evaporation at Texas A&M University, and by pulsed laser deposition (PLD) at the University of Wollongong, Australia. The latter of these techniques is widely used for growing thin films of various compounds. Single...

  7. Atom Interferometry

    ScienceCinema (OSTI)

    Mark Kasevich

    2010-01-08T23:59:59.000Z

    Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton?s constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gryoscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be sued to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?

  8. Intrafacet migration effects in InGaN/GaN structures grown on triangular GaN ridges studied by submicron beam x-ray diffraction

    E-Print Network [OSTI]

    Sirenko, Andrei

    Intrafacet migration effects in InGaN/GaN structures grown on triangular GaN ridges studied for x-ray diffraction and reciprocal space mapping of InGaN/GaN multiple-quantum-well MQW structures grown on the sidewalls of 10- m-wide triangular GaN ridges with 1-1.1 facets. Samples were produced

  9. Cr Atom Alignment in Cr-Delta-Doped GaN

    SciTech Connect (OSTI)

    Kimura, S.; Emura, S.; Zhou, Y. K.; Choi, S. W.; Yamauchi, Y.; Hasegawa, S.; Asahi, H. [Institute of Scientific and Industrial Research, Osaka University, 8-1, Mihogaoka, Osaka, 567-0047 (Japan); Ofuchi, H. [SPring-8 / Japan Synchrotron Radiation Research Institute (JASRI), Sayo, Hyogo 679-5198 (Japan); Nakata, Y. [College of Science and Engineering, Iwaki Meisei University, Iwaki, Fukushima 970-8551 (Japan)

    2007-02-02T23:59:59.000Z

    Structural properties and Cr atom alignments in Cr-delta doped GaN grown by molecular beam epitaxy are studied with transmission electron microscopy and X-ray absorption fine structure (XAFS) measurements. It is found that the environment around Cr atoms in delta-doped samples is dramatically changed under various growth conditions. The XAFS analysis of these synthesized layers suggests that new Cr-related complexes are grown.

  10. Morphology and Oxide Shell Structure of Iron Nanoparticles Grown...

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

    Oxide Shell Structure of Iron Nanoparticles Grown by Sputter-Gas-Aggregation. Morphology and Oxide Shell Structure of Iron Nanoparticles Grown by Sputter-Gas-Aggregation. Abstract:...

  11. Comparison of electronic structure of as grown and solar grade silicon samples

    SciTech Connect (OSTI)

    Saravanan, R., E-mail: saragow@dataone.in; Sheeba, R. A. J. R. [Madura College, Research Centre and PG Department of Physics (India)

    2012-04-15T23:59:59.000Z

    A comparison of the electronic structure of two different types of silicon materials viz., (i) as grown silicon and (ii) solar silicon has been carried out utilizing maximum entropy method and pair distribution function using powder X-ray data sets. The precise electron density maps have been elucidated for the two samples. The covalent nature of the bonding between atoms in both the samples is found to be well pronounced and clearly seen from the electron density maps. The electron densities at the middle of the Si-Si bond are found to be 0.47 and 0.45 e/A{sup 3} for as grown silicon and solar silicon respectively. In this work, the local structural information has also been obtained by analyzing the atomic pair distribution functions of these two samples.

  12. Anomalous diffusion of Ga and As from semi-insulating GaAs substrate into MOCVD grown ZnO films as a function of annealing temperature and its effect on charge compensation

    SciTech Connect (OSTI)

    Biswas, Pranab; Banerji, P., E-mail: pallab@matsc.iitkgp.ernet.in [Materials Science Centre, Indian Institute of Technology, Kharagpur 721 302 (India); Halder, Nripendra N. [Advanced Technology Development Centre, Indian Institute of Technology, Kharagpur 721 302 (India)] [Advanced Technology Development Centre, Indian Institute of Technology, Kharagpur 721 302 (India); Kundu, Souvik [School of Electrical Engineering and Computer Science, Oregon State University, 1148 Kelley Engineering Center, Corvallis, OR 97331–5501 (United States)] [School of Electrical Engineering and Computer Science, Oregon State University, 1148 Kelley Engineering Center, Corvallis, OR 97331–5501 (United States); Shripathi, T.; Gupta, M. [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 001 (India)] [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 001 (India)

    2014-05-15T23:59:59.000Z

    The diffusion behavior of arsenic (As) and gallium (Ga) atoms from semi-insulating GaAs (SI-GaAs) into ZnO films upon post-growth annealing vis-à-vis the resulting charge compensation was investigated with the help of x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy. The films, annealed at 600 ºC and 700 ºC showed p-type conductivity with a hole concentration of 1.1 × 10{sup 18} cm{sup ?3} and 2.8 × 10{sup 19} cm{sup ?3} respectively, whereas those annealed at 800 ºC showed n-type conductivity with a carrier concentration of 6.5 × 10{sup 16} cm{sup ?3}. It is observed that at lower temperatures, large fraction of As atoms diffused from the SI-GaAs substrates into ZnO and formed acceptor related complex, (As{sub Zn}–2V{sub Zn}), by substituting Zn atoms (As{sub Zn}) and thereby creating two zinc vacancies (V{sub Zn}). Thus as-grown ZnO which was supposed to be n-type due to nonstoichiometric nature showed p-type behavior. On further increasing the annealing temperature to 800 ºC, Ga atoms diffused more than As atoms and substitute Zn atoms thereby forming shallow donor complex, Ga{sub Zn}. Electrons from donor levels then compensate the p-type carriers and the material reverts back to n-type. Thus the conversion of carrier type took place due to charge compensation between the donors and acceptors in ZnO and this compensation is the possible origin of anomalous conduction in wide band gap materials.

  13. C incorporation in epitaxial Ge1yCy layers grown on Ge,,001...: An ab initio study D. Gall, J. D'Arcy-Gall, and J. E. Greene

    E-Print Network [OSTI]

    Gall, Daniel

    C incorporation in epitaxial Ge1ÀyCy layers grown on Ge,,001...: An ab initio study D. Gall, J. D lattice site configurations in fully coherent Ge1 yCy layers grown on Ge 001 . Calculations using strained configuration involving only one C atom per configura- tion. The bond-centered interstitial and the Ge-C split

  14. Measuring Atomic Properties with an Atom Interferometer

    E-Print Network [OSTI]

    Roberts, Tony David

    2006-06-28T23:59:59.000Z

    Two experiments are presented which measure atomic properties using an atom interferometer. The interferometer splits the sodium de Broglie wave into two paths,

  15. Effect of growth temperature on defects in epitaxial GaN film grown by plasma assisted molecular beam epitaxy

    SciTech Connect (OSTI)

    Kushvaha, S. S., E-mail: kushvahas@nplindia.org; Pal, P.; Shukla, A. K.; Joshi, Amish G.; Gupta, Govind; Kumar, M.; Singh, S.; Gupta, Bipin K.; Haranath, D. [CSIR- National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi, India 110012 (India)] [CSIR- National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi, India 110012 (India)

    2014-02-15T23:59:59.000Z

    We report the effect of growth temperature on defect states of GaN epitaxial layers grown on 3.5 ?m thick GaN epi-layer on sapphire (0001) substrates using plasma assisted molecular beam epitaxy. The GaN samples grown at three different substrate temperatures at 730, 740 and 750 °C were characterized using atomic force microscopy and photoluminescence spectroscopy. The atomic force microscopy images of these samples show the presence of small surface and large hexagonal pits on the GaN film surfaces. The surface defect density of high temperature grown sample is smaller (4.0 × 10{sup 8} cm{sup ?2} at 750 °C) than that of the low temperature grown sample (1.1 × 10{sup 9} cm{sup ?2} at 730 °C). A correlation between growth temperature and concentration of deep centre defect states from photoluminescence spectra is also presented. The GaN film grown at 750 °C exhibits the lowest defect concentration which confirms that the growth temperature strongly influences the surface morphology and affects the optical properties of the GaN epitaxial films.

  16. Atomic magnetometer

    DOE Patents [OSTI]

    Schwindt, Peter (Albuquerque, NM); Johnson, Cort N. (Albuquerque, NM)

    2012-07-03T23:59:59.000Z

    An atomic magnetometer is disclosed which uses a pump light beam at a D1 or D2 transition of an alkali metal vapor to magnetically polarize the vapor in a heated cell, and a probe light beam at a different D2 or D1 transition to sense the magnetic field via a polarization rotation of the probe light beam. The pump and probe light beams are both directed along substantially the same optical path through an optical waveplate and through the heated cell to an optical filter which blocks the pump light beam while transmitting the probe light beam to one or more photodetectors which generate electrical signals to sense the magnetic field. The optical waveplate functions as a quarter waveplate to circularly polarize the pump light beam, and as a half waveplate to maintain the probe light beam linearly polarized.

  17. AFLATOXIN CONTAMINATION OF COMMERCIALLY GROWN TRANSGENIC

    E-Print Network [OSTI]

    Cotty, Peter J.

    108 AFLATOXIN CONTAMINATION OF COMMERCIALLY GROWN TRANSGENIC BT COTTONSEED P.J. Cotty and C. Bock cotton may have reduced susceptibility to aflatoxin contamination as a result of pink bollworm resistance) from one highly contaminated (>6,000 ppb aflatoxin B1) Bt seed lot indicated that most contamination

  18. Transport studies on CVD-grown graphene

    E-Print Network [OSTI]

    Huntley, Miriam Hanna

    2009-01-01T23:59:59.000Z

    In this thesis, we report transport studies performed on CVD-grown graphene. We perform resistivity and hall measurements on a large-area sample at 4' K. We measure the carrier mobility of the sample and find it to be on ...

  19. Wide-Bandgap Semiconductors

    SciTech Connect (OSTI)

    Chinthavali, M.S.

    2005-11-22T23:59:59.000Z

    With the increase in demand for more efficient, higher-power, and higher-temperature operation of power converters, design engineers face the challenge of increasing the efficiency and power density of converters [1, 2]. Development in power semiconductors is vital for achieving the design goals set by the industry. Silicon (Si) power devices have reached their theoretical limits in terms of higher-temperature and higher-power operation by virtue of the physical properties of the material. To overcome these limitations, research has focused on wide-bandgap materials such as silicon carbide (SiC), gallium nitride (GaN), and diamond because of their superior material advantages such as large bandgap, high thermal conductivity, and high critical breakdown field strength. Diamond is the ultimate material for power devices because of its greater than tenfold improvement in electrical properties compared with silicon; however, it is more suited for higher-voltage (grid level) higher-power applications based on the intrinsic properties of the material [3]. GaN and SiC power devices have similar performance improvements over Si power devices. GaN performs only slightly better than SiC. Both SiC and GaN have processing issues that need to be resolved before they can seriously challenge Si power devices; however, SiC is at a more technically advanced stage than GaN. SiC is considered to be the best transition material for future power devices before high-power diamond device technology matures. Since SiC power devices have lower losses than Si devices, SiC-based power converters are more efficient. With the high-temperature operation capability of SiC, thermal management requirements are reduced; therefore, a smaller heat sink would be sufficient. In addition, since SiC power devices can be switched at higher frequencies, smaller passive components are required in power converters. Smaller heat sinks and passive components result in higher-power-density power converters. With the advent of the use of SiC devices it is imperative that models of these be made available in commercial simulators. This enables power electronic designers to simulate their designs for various test conditions prior to fabrication. To build an accurate transistor-level model of a power electronic system such as an inverter, the first step is to characterize the semiconductor devices that are present in the system. Suitable test beds need to be built for each device to precisely test the devices and obtain relevant data that can be used for modeling. This includes careful characterization of the parasitic elements so as to emulate the test setup as closely as possible in simulations. This report is arranged as follows: Chapter 2--The testing and characterization of several diodes and power switches is presented. Chapter 3--A 55-kW hybrid inverter (Si insulated gate bipolar transistor--SiC Schottky diodes) device models and test results are presented. A detailed description of the various test setups followed by the parameter extraction, modeling, and simulation study of the inverter performance is presented. Chapter 4--A 7.5-kW all-SiC inverter (SiC junction field effect transistors (JFET)--SiC Schottky diodes) was built and tested. The models built in Saber were validated using the test data and the models were used in system applications in the Saber simulator. The simulation results and a comparison of the data from the prototype tests are discussed in this chapter. Chapter 5--The duration test results of devices utilized in buck converters undergoing reliability testing are presented.

  20. Defect studies in low-temperature-grown GaAs

    SciTech Connect (OSTI)

    Bliss, D.E.

    1992-11-01T23:59:59.000Z

    High content of excess As is incorporated in GaAs grown by low-temperature molecular-beam-epitaxy (LTMBE). The excess As exists primarily as As antisite defects AsGa and a lesser extent of gallium vacancies V[sub Ga]. The neutral AsGa-related defects were measured by infrared absorption at 1[mu]m. Gallium vacancies, V[sub Ga], was investigated by slow positron annihilation. Dependence of defect contents on doping was studied by Si and Be dopants. No free carriers are generated by n-type or p-type doping up to 10[sup 19] cm[sup [minus]3] Si or Be. Raman data indicate Be occupies Ga substitutional sites but Si atom is not substitutional. Si induces more As[sub Ga] in the layer. As As[sub Ga] increases, photoquenchable As[sub Ga] decreases. Fraction of photoquenchable defects correlates to defects within 3 nearest neighbor separations disrupting the metastability. Annealing reduces neutral As[sub Ga] content around 500C, similar to irradiation damaged and plastically deformed Ga[sub As], as opposed to bulk grown GaAs in which As[sub Ga]-related defects are stable up to 1100C. The lower temperature defect removal is due to V[sub Ga] enhanced diffusion of As[sub Ga] to As precipitates. The supersaturated V[sub GA] and also decreases during annealing. Annealing kinetics for As[sub Ga]-related defects gives 2.0 [plus minus] 0.3 eV and 1.5 [plus minus] 0.3 eV migration enthalpies for the As[sub Ga] and V[sub Ga]. This represents the difference between Ga and As atoms hopping into the vacancy. The non-photoquenchable As[sub Ga]-related defects anneal with an activation energy of 1.1 [plus minus] 0.3eV. Be acceptors can be activated by 800C annealing. Temperature difference between defect annealing and Be activation formation of As[sub Ga]-Be[sub Ga] pairs. Si donors can only be partially activated.

  1. Conductivity of Oriented Samaria-Doped Ceria Thin Films Grown...

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

    Conductivity of Oriented Samaria-Doped Ceria Thin Films Grown by Oxygen-plasma-assisted Molecular Beam Epitaxy. Conductivity of Oriented Samaria-Doped Ceria Thin Films Grown by...

  2. Counting molecular-beam grown graphene layers

    SciTech Connect (OSTI)

    Plaut, Annette S. [School of Physics, University of Exeter, Exeter EX4 4QL (United Kingdom)] [School of Physics, University of Exeter, Exeter EX4 4QL (United Kingdom); Wurstbauer, Ulrich [Department of Physics, Columbia University, New York, New York 10027 (United States)] [Department of Physics, Columbia University, New York, New York 10027 (United States); Pinczuk, Aron [Department of Physics, Columbia University, New York, New York 10027 (United States) [Department of Physics, Columbia University, New York, New York 10027 (United States); Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States); Garcia, Jorge M. [MBE Lab, IMM-Instituto de Microelectronica de Madrid (CNM-CSIC), Madrid, E-28760 (Spain)] [MBE Lab, IMM-Instituto de Microelectronica de Madrid (CNM-CSIC), Madrid, E-28760 (Spain); Pfeiffer, Loren N. [Electrical Engineering Department, Princeton University, New Jersey 08544 (United States)] [Electrical Engineering Department, Princeton University, New Jersey 08544 (United States)

    2013-06-17T23:59:59.000Z

    We have used the ratio of the integrated intensity of graphene's Raman G peak to that of the silicon substrate's first-order optical phonon peak, accurately to determine the number of graphene layers across our molecular-beam (MB) grown graphene films. We find that these results agree well both, with those from our own exfoliated single and few-layer graphene flakes, and with the results of Koh et al.[ACS Nano 5, 269 (2011)]. We hence distinguish regions of single-, bi-, tri-, four-layer, etc., graphene, consecutively, as we scan coarsely across our MB-grown graphene. This is the first, but crucial, step to being able to grow, by such molecular-beam-techniques, a specified number of large-area graphene layers, to order.

  3. Hydrothermally grown nanostructured WO films and their electrochromic characteristics

    E-Print Network [OSTI]

    Demir, Hilmi Volkan

    Hydrothermally grown nanostructured WO 3 films and their electrochromic characteristics.1088/0022-3727/43/28/285501 Hydrothermally grown nanostructured WO3 films and their electrochromic characteristics Zhihui Jiao1 , Xiao Wei and their electrochromic characteristics. Plate-like monoclinic WO3 nanostructures were grown directly on fluorine

  4. atom-atom collisions: Topics by E-print Network

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

    Atomic Safronova, Marianna 3 Atom-atom correlations in colliding Bose-Einstein condensates Quantum Physics (arXiv) Summary: We analyze atom-atom correlations in the s-wave...

  5. Unexpected behaviour of one Pb monolayer deposited on aluminum oxide thin film grown on Ag(111)

    SciTech Connect (OSTI)

    Vizzini, Sébastien, E-mail: sebastien.vizzini@im2np.fr; Bertoglio, M. [IM2NP CNRS, Aix Marseille Université, F-13397 Marseille (France)] [IM2NP CNRS, Aix Marseille Université, F-13397 Marseille (France); Oughaddou, Hamid [Institut des Sciences Moléculaires d'Orsay, ISMO CNRS, Université de Paris, F-91405 Orsay, France and Deptartamento de Physique, Université de Cergy-Pontoise, F-95031 Cergy-Pontoise (France)] [Institut des Sciences Moléculaires d'Orsay, ISMO CNRS, Université de Paris, F-91405 Orsay, France and Deptartamento de Physique, Université de Cergy-Pontoise, F-95031 Cergy-Pontoise (France); Hoarau, J. Y.; Biberian, J. P.; Aufray, B. [CINaM CNRS, Aix Marseille Université, F-13288 Marseille (France)] [CINaM CNRS, Aix Marseille Université, F-13288 Marseille (France)

    2013-12-23T23:59:59.000Z

    Using scanning tunneling microscopy (STM), Auger electron spectroscopy, and low energy electron diffraction, we have observed a surprising complete dissolution at room temperature of one lead monolayer deposited by evaporation on an aluminum oxide thin film (?0.8?nm thick) previously grown on Ag (111). We have observed the quasi-instantaneous diffusion of the lead deposit through the oxide layer to the silver/oxide interface. After the diffusion process, lead atoms form a Moiré superstructure, which is characterized by STM through the oxide layer. This unexpected behavior puts in light the very weak interaction between the aluminum oxide and the silver substrate.

  6. ATOMIC-LAYER-DEPOSITED ALUMINUM OXIDE FOR THE SURFACE PASSIVATION OF HIGH-EFFICIENCY SILICON SOLAR CELLS

    E-Print Network [OSTI]

    ATOMIC-LAYER-DEPOSITED ALUMINUM OXIDE FOR THE SURFACE PASSIVATION OF HIGH-EFFICIENCY SILICON SOLAR to those measured on reference cells passivated by an aluminum-annealed thermal SiO2, while those of the Al of aluminum ox- ide (Al2O3) grown by atomic layer deposition (ALD) pro- vide an excellent level of sur

  7. Spatial modulation of in-plane magnetic anisotropy in epitaxial Co(111) films grown on macrostep-bunched Si(111)

    SciTech Connect (OSTI)

    Davydenko, A. V., E-mail: avdavydenko@gmail.com; Kozlov, A. G.; Chebotkevich, L. A. [Laboratory of Thin Film Technologies, Far Eastern Federal University, Vladivostok 690950 (Russian Federation)

    2014-10-14T23:59:59.000Z

    We compared magnetic properties of epitaxial Co(111) films grown on microstep- and macrostep-bunched vicinal Si(111) substrates. A surface of the microstep-bunched Si(111) substrate represents regular array of step-bunches with height of 1.7 nm divided from each other by flat microterraces with a width of 34 nm. A surface of the macrostep-bunched Si(111) substrate is constituted by macrostep bunches with a height of 75–85 nm divided by atomically flat macroterraces. The average sum width of a macrostep bunch and a macroterrace is 2.3 ?m. While in-plane magnetic anisotropy was spatially uniform in Co(111) films grown on the microstep-bunched Si(111), periodic macromodulation of the topography of the Si(111) substrate induced spatial modulation of in-plane magnetic anisotropy in Co(111) film grown on the macrostep-bunched Si(111) surface. The energy of uniaxial magnetic anisotropy in the areas of the Co(111) film deposited on the Si(111) macrosteps was higher more than by the order of magnitude than the energy of the magnetic anisotropy in the areas grown on macroterraces. Magnetization reversal in the areas with different energy of the magnetic anisotropy occurred in different magnetic fields. We showed the possibility of obtaining high density of domain walls in Co(111) film grown on the macrostep-bunched Si(111) by tuning the spatial step density of the Si(111) substrate.

  8. Modeling and control of undesirable dynamics in atomic force microscopes

    E-Print Network [OSTI]

    El Rifai, Osamah M

    2002-01-01T23:59:59.000Z

    The phenomenal resolution and versatility of the atomic force microscope (AFM), has made it a widely-used instrument in nanotechnology. In this thesis, a detailed model of AFM dynamics has been developed. It includes a new ...

  9. Nanoscale structure and transport : from atoms to devices

    E-Print Network [OSTI]

    Evans, Matthew Hiram

    2005-01-01T23:59:59.000Z

    Nanoscale structures present both unique physics and unique theoretical challenges. Atomic-scale simulations can find novel nanostructures with desirable properties, but the search can be difficult if the wide range of ...

  10. Driven Ratchets for Cold Atoms

    E-Print Network [OSTI]

    Renzoni, F

    2011-01-01T23:59:59.000Z

    Brownian motors, or ratchets, are devices which "rectify" Brownian motion, i.e. they can generate a current of particles out of unbiased fluctuations. The ratchet effect is a very general phenomenon which applies to a wide range of physical systems, and indeed ratchets have been realized with a variety of solid state devices, with optical trap setups as well as with synthetic molecules and granular gases. The present article reviews recent experimental realizations of ac driven ratchets with cold atoms in driven optical lattices. This is quite an unusual system for a Brownian motor as there is no a real thermal bath, and both the periodic potential for the atoms and the fluctuations are determined by laser fields. Such a system allowed us to realize experimentally rocking and gating ratchets, and to precisely investigate the relationship between symmetry and transport in these ratchets, both for the case of periodic and quasiperiodic driving.

  11. Driven Ratchets for Cold Atoms

    E-Print Network [OSTI]

    F. Renzoni

    2011-12-05T23:59:59.000Z

    Brownian motors, or ratchets, are devices which "rectify" Brownian motion, i.e. they can generate a current of particles out of unbiased fluctuations. The ratchet effect is a very general phenomenon which applies to a wide range of physical systems, and indeed ratchets have been realized with a variety of solid state devices, with optical trap setups as well as with synthetic molecules and granular gases. The present article reviews recent experimental realizations of ac driven ratchets with cold atoms in driven optical lattices. This is quite an unusual system for a Brownian motor as there is no a real thermal bath, and both the periodic potential for the atoms and the fluctuations are determined by laser fields. Such a system allowed us to realize experimentally rocking and gating ratchets, and to precisely investigate the relationship between symmetry and transport in these ratchets, both for the case of periodic and quasiperiodic driving.

  12. Atomic moments in Mn2CoAl thin films analyzed by X-ray magnetic circular dichroism

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jamer, M. [Northwestern Univ., Evanston, IL (United States). Dept. of Physics; Sterbinsky, G. [Brookhaven National Laboratory (BNL), Upton, NY (United States). Photon Sciences Directorate; Assaf, B. [Northwestern Univ., Evanston, IL (United States). Dept. of Physics; Arena, D. [Brookhaven National Laboratory (BNL), Upton, NY (United States). Photon Sciences Directorate; Heiman, D. [Northwestern Univ., Evanston, IL (United States). Dept. of Physics

    2014-12-07T23:59:59.000Z

    Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. The results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value. (auth)

  13. Ultrathin epitaxially grown bismuth (111) membranes

    SciTech Connect (OSTI)

    Payer, T.; Rajkovic, I.; Ligges, M.; Linde, D. von der [Fachbereich Physik, Universitaet Duisburg-Essen, Lotharstrasse 1, 47057 Duisburg (Germany); Horn-von Hoegen, M.; Meyer zu Heringdorf, F.-J. [Fachbereich Physik, Universitaet Duisburg-Essen, Lotharstrasse 1, 47057 Duisburg (Germany); Center for Nanointegration (CeNIDE), Universitaet Duisburg-Essen, Lotharstrasse 1, 47057 Duisburg (Germany)

    2008-09-01T23:59:59.000Z

    An ex situ cleaning and etching technique was applied to NaCl single crystals to prepare atomically flat and clean NaCl surfaces. These were used as substrates for molecular beam epitaxial growth of ultrathin continuous Bi(111) films. The high film quality - as studied with low energy electron diffraction, atomic force microscopy, and transmission electron diffraction - is attributed to the commensurate 10:7 ratio of the lattice constants. Dissolving the NaCl substrates in water allows the fabrication of freestanding 20 nm thin Bi(111) membranes of centimeter size.

  14. Magnetization dynamics of cobalt grown on graphene

    SciTech Connect (OSTI)

    Berger, A. J.; White, S. P.; Adur, R.; Pu, Y.; Hammel, P. C., E-mail: hammel@physics.osu.edu [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Amamou, W. [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States); Kawakami, R. K. [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States)

    2014-05-07T23:59:59.000Z

    Ferromagnetic resonance (FMR) spin pumping is a rapidly growing field which has demonstrated promising results in a variety of material systems. This technique utilizes the resonant precession of magnetization in a ferromagnet to inject spin into an adjacent non-magnetic material. Spin pumping into graphene is attractive on account of its exceptional spin transport properties. This article reports on FMR characterization of cobalt grown on chemical vapor deposition graphene and examines the validity of linewidth broadening as an indicator of spin pumping. In comparison to cobalt samples without graphene, direct contact cobalt-on-graphene exhibits increased FMR linewidth—an often used signature of spin pumping. Similar results are obtained in Co/MgO/graphene structures, where a 1?nm MgO layer acts as a tunnel barrier. However, magnetometry, magnetic force microscopy, and Kerr microscopy measurements demonstrate increased magnetic disorder in cobalt grown on graphene, perhaps due to changes in the growth process and an increase in defects. This magnetic disorder may account for the observed linewidth enhancement due to effects such as two-magnon scattering or mosaicity. As such, it is not possible to conclude successful spin injection into graphene from FMR linewidth measurements alone.

  15. Carbon nanotube forests growth using catalysts from atomic layer deposition

    SciTech Connect (OSTI)

    Chen, Bingan; Zhang, Can; Esconjauregui, Santiago; Xie, Rongsi; Zhong, Guofang; Robertson, John [Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom); Bhardwaj, Sunil [Istituto Officina dei Materiali-CNR Laboratorio TASC, s.s. 14, km 163.4, I-34012 Trieste (Italy); Sincrotone Trieste S.C.p.A., s.s. 14, km 163.4, I-34149 Trieste (Italy); Cepek, Cinzia [Istituto Officina dei Materiali-CNR Laboratorio TASC, s.s. 14, km 163.4, I-34012 Trieste (Italy)

    2014-04-14T23:59:59.000Z

    We have grown carbon nanotubes using Fe and Ni catalyst films deposited by atomic layer deposition. Both metals lead to catalytically active nanoparticles for growing vertically aligned nanotube forests or carbon fibres, depending on the growth conditions and whether the substrate is alumina or silica. The resulting nanotubes have narrow diameter and wall number distributions that are as narrow as those grown from sputtered catalysts. The state of the catalyst is studied by in-situ and ex-situ X-ray photoemission spectroscopy. We demonstrate multi-directional nanotube growth on a porous alumina foam coated with Fe prepared by atomic layer deposition. This deposition technique can be useful for nanotube applications in microelectronics, filter technology, and energy storage.

  16. Wide field of view telescope

    DOE Patents [OSTI]

    Ackermann, Mark R. (Albuquerque, NM); McGraw, John T. (Placitas, NM); Zimmer, Peter C. (Albuquerque, NM)

    2008-01-15T23:59:59.000Z

    A wide field of view telescope having two concave and two convex reflective surfaces, each with an aspheric surface contour, has a flat focal plane array. Each of the primary, secondary, tertiary, and quaternary reflective surfaces are rotationally symmetric about the optical axis. The combination of the reflective surfaces results in a wide field of view in the range of approximately 3.8.degree. to approximately 6.5.degree.. The length of the telescope along the optical axis is approximately equal to or less than the diameter of the largest of the reflective surfaces.

  17. Uranium immobilization by sulfate-reducing biofilms grown on...

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

    of uranium-complexing carbonates. The biofilms were grown in three identically operated fixed bed reactors, filled with three types of minerals: one noncarbonate-bearing...

  18. Atomizing nozzle and process

    DOE Patents [OSTI]

    Anderson, I.E.; Figliola, R.S.; Molnar, H.M.

    1993-07-20T23:59:59.000Z

    High pressure atomizing nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt atomization. The atomizing nozzle is especially useful in atomizing rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum magnetic properties.

  19. SOFTWAREENGINEERING The World Wide Web

    E-Print Network [OSTI]

    Whitehead, James

    SOFTWAREENGINEERING The World Wide Web Distributed Authoring and Versioning working group on the Web. WEBDAV: IETF Standard for Collaborative Authoring on the Web E. JAMES WHITEHEAD, JR. University remains to be done. What if instead you could simply edit Web documents (or any Web resource) in place

  20. Going Deep vs. Going Wide

    Broader source: Energy.gov [DOE]

    Going Deep vs. Going Wide, from the Residential Energy Efficiency Solutions Conference 2012. Provides an overview on the progress of four energy efficiency programs: Clean Energy Works Oregon, Efficiency Maine, Energy Upgrade California Flex Path, and EcoHouse Loan Program.

  1. Atomic swelling upon compression

    E-Print Network [OSTI]

    V. K. Dolmatov; J. L. King

    2012-08-18T23:59:59.000Z

    The hydrogen atom under the pressure of a spherical penetrable confinement potential of a decreasing radius $r_{0}$ is explored, as a case study. A novel counter-intuitive effect of atomic swelling rather than shrinking with decreasing $r_{0}$ is unraveled, when $r_{0}$ reaches, and remains smaller than, a certain critical value. Upon swelling, the size of the atom is shown to increase by an order of magnitude, or more, compared to the size of the free atom. Examples of changes of photoabsorption properties of confined hydrogen atom upon its swelling are uncovered and demonstrated.

  2. Wide Bandgap Extrinsic Photoconductive Switches

    SciTech Connect (OSTI)

    Sullivan, J S

    2012-01-17T23:59:59.000Z

    Photoconductive semiconductor switches (PCSS) have been investigated since the late 1970s. Some devices have been developed that withstand tens of kilovolts and others that switch hundreds of amperes. However, no single device has been developed that can reliably withstand both high voltage and switch high current. Yet, photoconductive switches still hold the promise of reliable high voltage and high current operation with subnanosecond risetimes. Particularly since good quality, bulk, single crystal, wide bandgap semiconductor materials have recently become available. In this chapter we will review the basic operation of PCSS devices, status of PCSS devices and properties of the wide bandgap semiconductors 4H-SiC, 6H-SiC and 2H-GaN.

  3. Atom trap trace analysis of krypton isotopes

    SciTech Connect (OSTI)

    Bailey, K.; Chen, C. Y.; Du, X.; Li, Y. M.; Lu, Z.-T.; O'Connor, T. P.; Young, L.

    1999-11-17T23:59:59.000Z

    A new method of ultrasensitive isotope trace analysis has been developed. This method, based on the technique of laser manipulation of neutral atoms, has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton gas sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. This method is free of contamination from other isotopes and elements and can be applied to several different isotope tracers for a wide range of applications. The demonstrated detection efficiency is 1 x 10{sup {minus}7}. System improvements could increase the efficiency by many orders of magnitude.

  4. Supplementary Information for Field Ionization of Cold Atoms Near the Wall of a Single Carbon Nanotube

    E-Print Network [OSTI]

    Hau, Lene Vestergaard

    1 Supplementary Information for Field Ionization of Cold Atoms Near the Wall of a Single Carbon with suspended nanotubes. Single-walled carbon nanotubes, suspended across 10-m gaps, are grown on silicon chips is applied with clip connections to the pads. The electrode design was optimized with numerical modelling

  5. “Hard probes” of strongly-interacting atomic gases

    SciTech Connect (OSTI)

    Nishida, Yusuke [Los Alamos National Laboratory

    2012-06-18T23:59:59.000Z

    We investigate properties of an energetic atom propagating through strongly interacting atomic gases. The operator product expansion is used to systematically compute a quasiparticle energy and its scattering rate both in a spin-1/2 Fermi gas and in a spinless Bose gas. Reasonable agreement with recent quantum Monte Carlo simulations even at a relatively small momentum k/kF > 1.5 indicates that our large-momentum expansions are valid in a wide range of momentum. We also study a differential scattering rate when a probe atom is shot into atomic gases. Because the number density and current density of the target atomic gas contribute to the forward scattering only, its contact density (measure of short-range pair correlation) gives the leading contribution to the backward scattering. Therefore, such an experiment can be used to measure the contact density and thus provides a new local probe of strongly interacting atomic gases.

  6. Opportunities for Wide Bandgap Semiconductor Power Electronics...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen...

  7. Improved graphite furnace atomizer

    DOE Patents [OSTI]

    Siemer, D.D.

    1983-05-18T23:59:59.000Z

    A graphite furnace atomizer for use in graphite furnace atomic absorption spectroscopy is described wherein the heating elements are affixed near the optical path and away from the point of sample deposition, so that when the sample is volatilized the spectroscopic temperature at the optical path is at least that of the volatilization temperature, whereby analyteconcomitant complex formation is advantageously reduced. The atomizer may be elongated along its axis to increase the distance between the optical path and the sample deposition point. Also, the atomizer may be elongated along the axis of the optical path, whereby its analytical sensitivity is greatly increased.

  8. Atomic Collapse Observed

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

    Scientists Observe Atomic Collapse State Quantum Mechanics Prediction Confirmed in Graphene Using NERSC's Hopper April 26, 2013 | Tags: Hopper, Materials Science Contact: Linda...

  9. Wide-range voltage modulation

    SciTech Connect (OSTI)

    Rust, K.R.; Wilson, J.M.

    1992-06-01T23:59:59.000Z

    The Superconducting Super Collider`s Medium Energy Booster Abort (MEBA) kicker modulator will supply a current pulse to the abort magnets which deflect the proton beam from the MEB ring into a designated beam stop. The abort kicker will be used extensively during testing of the Low Energy Booster (LEB) and the MEB rings. When the Collider is in full operation, the MEBA kicker modulator will abort the MEB beam in the event of a malfunction during the filling process. The modulator must generate a 14-{mu}s wide pulse with a rise time of less than 1 {mu}s, including the delay and jitter times. It must also be able to deliver a current pulse to the magnet proportional to the beam energy at any time during ramp-up of the accelerator. Tracking the beam energy, which increases from 12 GeV at injection to 200 GeV at extraction, requires the modulator to operate over a wide range of voltages (4 kV to 80 kV). A vacuum spark gap and a thyratron have been chosen for test and evaluation as candidate switches for the abort modulator. Modulator design, switching time delay, jitter and pre-fire data are presented.

  10. Atomic moments in Mn2CoAl thin films analyzed by X-ray magnetic circular dichroism

    SciTech Connect (OSTI)

    Jamer, M. [Northwestern Univ., Evanston, IL (United States). Dept. of Physics; Sterbinsky, G. [Brookhaven National Laboratory (BNL), Upton, NY (United States). Photon Sciences Directorate; Assaf, B. [Northwestern Univ., Evanston, IL (United States). Dept. of Physics; Arena, D. [Brookhaven National Laboratory (BNL), Upton, NY (United States). Photon Sciences Directorate; Heiman, D. [Northwestern Univ., Evanston, IL (United States). Dept. of Physics

    2014-12-07T23:59:59.000Z

    Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. The results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value. (auth)

  11. Structural Defects in Laterally Overgrown GaN Layers Grown on Non-polar Substrates

    E-Print Network [OSTI]

    Liliental-Weber, Z.; Ni, X.; Morkoc, H.

    2007-01-01T23:59:59.000Z

    Overgrown GaN Layers Grown on Non-polar Substrates Z.in GaN layers grown on polar and non-polar substrates areGaN-based layers, since they are grown heteroepitaxially on foreign substrates (

  12. Producing and Detecting Correlated atoms

    E-Print Network [OSTI]

    Christoph I. Westbrook; Martijn Schellekens; Aurélien Perrin; Valentina Krachmalnicoff; Jose Carlos Viana Gomes; Jean-Baptiste Trebbia; Jérôme Estève; Hong Chang; Isabelle Bouchoule; Denis Boiron; Alain Aspect; Tom Jeltes; John McNamara; Wim Hogervorst; Wim Vassen

    2006-09-04T23:59:59.000Z

    We discuss experiments to produce and detect atom correlations in a degenerate or nearly degenerate gas of neutral atoms. First we treat the atomic analog of the celebrated Hanbury Brown Twiss experiment, in which atom correlations result simply from interference effects without any atom interactions.We have performed this experiment for both bosons and fermions. Next we show how atom interactions produce correlated atoms using the atomic analog of spontaneous four-wavemixing. Finally, we briefly mention experiments on a one dimensional gas on an atom chip in which correlation effects due to both interference and interactions have been observed.

  13. Self-doping effects in epitaxially grown graphene

    E-Print Network [OSTI]

    Siegel, David A.

    2009-01-01T23:59:59.000Z

    The electronic properties of graphene, Rev. Mod. Phys. (inE?ects in Epitaxially-Grown Graphene D.A. Siegel, 1, 2 S.Y.2009) Abstract Self-doping in graphene has been studied by

  14. ag films grown: Topics by E-print Network

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

    conduction-band states of NiO 100 thin films grown onto Ag 100 have charac- terized NiO monocrystalline thin films has shown up both onto insulating i.e., MgO, Ref. 21 Marcon,...

  15. aln films grown: Topics by E-print Network

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

    conduction-band states of NiO 100 thin films grown onto Ag 100 have charac- terized NiO monocrystalline thin films has shown up both onto insulating i.e., MgO, Ref. 21 Marcon,...

  16. Lattice constant and substitutional composition of GeSn alloys grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Bhargava, Nupur; Coppinger, Matthew; Prakash Gupta, Jay; Kolodzey, James [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States)] [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States); Wielunski, Leszek [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 (United States)] [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 (United States)

    2013-07-22T23:59:59.000Z

    Single crystal epitaxial Ge{sub 1?x}Sn{sub x} alloys with atomic fractions of tin up to x = 0.145 were grown by solid source molecular beam epitaxy on Ge (001) substrates. The Ge{sub 1?x}Sn{sub x} alloys formed high quality, coherent, strained layers at growth temperatures below 250 °C, as shown by high resolution X-ray diffraction. The amount of Sn that was on lattice sites, as determined by Rutherford backscattering spectrometry channeling, was found to be above 90% substitutional in all alloys. The degree of strain and the dependence of the effective unstrained bulk lattice constant of Ge{sub 1?x}Sn{sub x} alloys versus the composition of Sn have been determined.

  17. High-quality strain-relaxed SiGe films grown with low temperature Si buffer

    SciTech Connect (OSTI)

    Luo, Y. H.; Wan, J.; Forrest, R. L.; Liu, J. L.; Goorsky, M. S.; Wang, K. L.

    2001-06-15T23:59:59.000Z

    High-quality strain-relaxed SiGe templates with a low threading dislocation density and smooth surface are critical for device performance. In this work, SiGe films on low temperature Si buffer layers were grown by solid-source molecular beam epitaxy and characterized by atomic force microscope, double-axis x-ray diffraction, photoluminescence spectroscopy, and Raman spectroscopy. Effects of the growth temperature and the thickness of the low temperature Si buffer were studied. It was demonstrated that when using proper growth conditions for the low temperature Si buffer the Si buffer became tensily strained and gave rise to the compliant effect. The lattice mismatch between the SiGe and the Si buffer layer was reduced. A 500 nm Si{sub 0.7}Ge{sub 0.3} film with a low threading dislocation density as well as smooth surface was obtained by this method. {copyright} 2001 American Institute of Physics.

  18. Geometrical characteristics and damage morphology of nodules grown from artificial seeds in multilayer coating

    SciTech Connect (OSTI)

    Shan Yongguang; He Hongbo; Wei Chaoyang; Li Shuhong; Zhou Ming; Li Dawei; Zhao Yuan'an

    2010-08-01T23:59:59.000Z

    Nodules have been planted in an HfO2/SiO2 multilayer system with absorptive gold nanoparticle seeds located on the surface of a substrate. The topography of nodules was scanned by an atomic force microscope and imaged by a scanning electron microscope. The underlying characteristics of nodules were revealed by a focused ion beam. The cross-sectional profiles reveal that nodules grown from small seeds have a continuous boundary and better mechanical stability. A laser-induced damage test shows that nodules decrease the laser-induced damage threshold by up to 3 times. The damage pits are exclusively caused by nodular ejection and triggered by the absorptive seeds. The distribution of electric field and average temperature rise in the nodules were analyzed. Theoretical results met experimental results very well. The strong absorptive seed and microlens effect of the nodule play important roles in laser-induced damage of a planted nodule.

  19. Processing quality of Texas-grown pinto beans

    E-Print Network [OSTI]

    Quenzer, Nancy Marie

    1977-01-01T23:59:59.000Z

    PROCESSING QUALITY OF TEXAS-GROWN PINTO BEANS A Thesis by Nancy Marie Quenzer Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1977 Major Subject...: Food Science and Technology PROCESSING QUALITY OF TEXAS-GROWN PINTO BEANS A Thesis by Nancy Marie Quenzer Approved as to style and content by: Chairman o ittee Member (Hea o Department Member Member August 1977 &421'. ' ABSTRACT Processing...

  20. Magnetic-film atom chip with 10 $?$m period lattices of microtraps for quantum information science with Rydberg atoms

    E-Print Network [OSTI]

    V. Y. F. Leung; D. R. M. Pijn; H. Schlatter; L. Torralbo-Campo; A. La Rooij; G. B. Mulder; J. Naber; M. L. Soudijn; A. Tauschinsky; C. Abarbanel; B. Hadad; E. Golan; R. Folman; R. J. C. Spreeuw

    2014-07-01T23:59:59.000Z

    We describe the fabrication and construction of a setup for creating lattices of magnetic microtraps for ultracold atoms on an atom chip. The lattice is defined by lithographic patterning of a permanent magnetic film. Patterned magnetic-film atom chips enable a large variety of trapping geometries over a wide range of length scales. We demonstrate an atom chip with a lattice constant of 10 $\\mu$m, suitable for experiments in quantum information science employing the interaction between atoms in highly-excited Rydberg energy levels. The active trapping region contains lattice regions with square and hexagonal symmetry, with the two regions joined at an interface. A structure of macroscopic wires, cut out of a silver foil, was mounted under the atom chip in order to load ultracold $^{87}$Rb atoms into the microtraps. We demonstrate loading of atoms into the square and hexagonal lattice sections simultaneously and show resolved imaging of individual lattice sites. Magnetic-film lattices on atom chips provide a versatile platform for experiments with ultracold atoms, in particular for quantum information science and quantum simulation.

  1. Magnetic-film atom chip with 10 ?m period lattices of microtraps for quantum information science with Rydberg atoms

    SciTech Connect (OSTI)

    Leung, V. Y. F. [Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, PO Box 94485, 1090 GL Amsterdam (Netherlands) [Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, PO Box 94485, 1090 GL Amsterdam (Netherlands); Complex Photonic Systems (COPS), MESA Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Pijn, D. R. M.; Schlatter, H.; Torralbo-Campo, L.; La Rooij, A. L.; Mulder, G. B.; Naber, J.; Soudijn, M. L.; Tauschinsky, A.; Spreeuw, R. J. C., E-mail: r.j.c.spreeuw@uva.nl [Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, PO Box 94485, 1090 GL Amsterdam (Netherlands)] [Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, PO Box 94485, 1090 GL Amsterdam (Netherlands); Abarbanel, C.; Hadad, B.; Golan, E. [Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Be'er Sheva 84105 (Israel)] [Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Be'er Sheva 84105 (Israel); Folman, R. [Department of Physics and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Be'er Sheva 84105 (Israel)] [Department of Physics and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Be'er Sheva 84105 (Israel)

    2014-05-15T23:59:59.000Z

    We describe the fabrication and construction of a setup for creating lattices of magnetic microtraps for ultracold atoms on an atom chip. The lattice is defined by lithographic patterning of a permanent magnetic film. Patterned magnetic-film atom chips enable a large variety of trapping geometries over a wide range of length scales. We demonstrate an atom chip with a lattice constant of 10 ?m, suitable for experiments in quantum information science employing the interaction between atoms in highly excited Rydberg energy levels. The active trapping region contains lattice regions with square and hexagonal symmetry, with the two regions joined at an interface. A structure of macroscopic wires, cutout of a silver foil, was mounted under the atom chip in order to load ultracold {sup 87}Rb atoms into the microtraps. We demonstrate loading of atoms into the square and hexagonal lattice sections simultaneously and show resolved imaging of individual lattice sites. Magnetic-film lattices on atom chips provide a versatile platform for experiments with ultracold atoms, in particular for quantum information science and quantum simulation.

  2. X-ray diffraction analysis of InGaP/GaAs heterointerfaces grown by metalorganic chemical vapor deposition

    SciTech Connect (OSTI)

    Nittono, T.; Hyuga, F. [NTT System Electronics Laboratories 3-1, Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-01 (Japan)] [NTT System Electronics Laboratories 3-1, Morinosato Wakamiya, Atsugi-shi, Kanagawa, 243-01 (Japan)

    1997-03-01T23:59:59.000Z

    InGaP/GaAs heterointerfaces grown by metalorganic chemical vapor deposition have been characterized by a high-resolution x-ray diffraction analysis of multiple quantum well structures. The flow of AsH{sub 3} to InGaP surface produces an InGaAs-like interfacial layer at the GaAs-on-InGaP interface, indicating P atoms of the InGaP surface are easily replaced by As atoms. The flow of PH{sub 3} to GaAs surface, on the other hand, does not make any detectable interfacial layer, indicating that almost no As atoms of the GaAs surface are replaced by P atoms. It is also found that the flow of trimethylgallium (TMG) to the InGaP surface produces a GaP-like interfacial layer. This interfacial layer is probably formed by the reaction between TMG and excessive P atoms on the InGaP surface or residual PH{sub 3} in the growth chamber. {copyright} {ital 1997 American Institute of Physics.}

  3. Comprehensive online Atomic Database Management System (DBMS) with Highly Qualified Computing Capabilities

    E-Print Network [OSTI]

    Tahat, Amani

    2011-01-01T23:59:59.000Z

    The intensive need of atomic data is expanding continuously in a wide variety of applications (e.g. fusion energy and astrophysics, laser-produced, plasma researches, and plasma processing).This paper will introduce our ongoing research work to build a comprehensive, complete, up-to-date, user friendly and online atomic Database Management System (DBMS) namely called AIMS by using SQLite (http://www.sqlite.org/about.html)(8). Programming language tools and techniques will not be covered here. The system allows the generation of various atomic data based on professional online atomic calculators. The ongoing work is a step forward to bring detailed atomic model accessible to a wide community of laboratory and astrophysical plasma diagnostics. AIMS is a professional worldwide tool for supporting several educational purposes and can be considered as a complementary database of IAEA atomic databases. Moreover, it will be an exceptional strategy of incorporating the output data of several atomic codes to external ...

  4. Atomic and molecular supernovae

    SciTech Connect (OSTI)

    Liu, W.

    1997-12-01T23:59:59.000Z

    Atomic and molecular physics of supernovae is discussed with an emphasis on the importance of detailed treatments of the critical atomic and molecular processes with the best available atomic and molecular data. The observations of molecules in SN 1987A are interpreted through a combination of spectral and chemical modelings, leading to strong constraints on the mixing and nucleosynthesis of the supernova. The non-equilibrium chemistry is used to argue that carbon dust can form in the oxygen-rich clumps where the efficient molecular cooling makes the nucleation of dust grains possible. For Type Ia supernovae, the analyses of their nebular spectra lead to strong constraints on the supernova explosion models.

  5. Atom probe tomography studies of Al?O? gate dielectrics on GaN

    SciTech Connect (OSTI)

    Mazumder, Baishakhi, E-mail: bmazumder@engineering.ucsb.edu; Wu, Feng; Speck, James S. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Liu, Xiang; Yeluri, Ramya; Mishra, Umesh K. [Electrical and Computer Engineering Department, University of California, Santa Barbara, California 93106 (United States)

    2014-10-07T23:59:59.000Z

    Atom probe tomography was used to achieve three-dimensional characterization of in situ Al?O?/GaN structures grown by metal organic chemical vapor deposition (MOCVD). Al?O? dielectrics grown at three different temperatures of 700, 900, and 1000 °C were analyzed and compared. A low temperature GaN cap layer grown atop Al?O? enabled a high success rate in the atom probe experiments. The Al?O?/GaN interfaces were found to be intermixed with Ga, N, and O over the distance of a few nm. Impurity measurements data showed that the 1000 °C sample contains higher amounts of C (4 × 10¹?/cm³) and lower amounts of H (7 × 10¹?/cm³), whereas the 700 °C sample exhibits lower C impurities (<10¹?/cm³) and higher H incorporation (2.2 × 10²?/cm³). On comparing with Al?O? grown by atomic layer deposition (ALD), it was found that the MOCVD Al?O?/GaN interface is comparatively abrupt. Scanning transmission electron microscopy data showed that the 900 °C and 1000 °C MOCVD films exhibit polycrystalline nature, while the ALD films were found to be amorphous.

  6. Isotropically sensitive optical filter employing atomic resonance transitions

    DOE Patents [OSTI]

    Marling, John B. (Livermore, CA)

    1981-01-01T23:59:59.000Z

    An ultra-high Q isotropically sensitive optical filter or optical detector employing atomic resonance transitions. More specifically, atomic resonance transitions utilized in conjunction with two optical bandpass filters provide an optical detector having a wide field of view (.about.2.pi. steradians) and very narrow acceptance bandwidth approaching 0.01 A. A light signal to be detected is transmitted through an outer bandpass filter into a resonantly absorbing atomic vapor, the excited atomic vapor then providing a fluorescence signal at a different wavelength which is transmitted through an inner bandpass filter. The outer and inner bandpass filters have no common transmission band, thereby resulting in complete blockage of all optical signals that are not resonantly shifted in wavelength by the intervening atomic vapor. Two embodiments are disclosed, one in which the light signal raises atoms contained in the atomic vapor from the ground state to an excited state from which fluorescence occurs, and the other in which a pump laser is used to raise the atoms in the ground state to a first excited state from which the light signal then is resonantly absorbed, thereby raising the atoms to a second excited state from which fluorescence occurs. A specific application is described in which an optical detector according to the present invention can be used as an underwater detector for light from an optical transmitter which could be located in an orbiting satellite.

  7. New results in atomic physics at the Advanced Light Source

    SciTech Connect (OSTI)

    Schlachter, A.S.

    1995-01-01T23:59:59.000Z

    The Advanced Light Source is the world's first low-energy third-generation synchrotron radiation source. It has been running reliably and exceeding design specifications since it began operation in October 1993. It is available to a wide community of researchers in many scientific fields, including atomic and molecular science and chemistry. Here, new results in atomic physics at the Advanced Light Source demonstrate the opportunities available in atomic and molecular physics at this synchrotron light source. The unprecedented brightness allows experiments with high flux, high spectral resolution, and nearly 100% linear polarization.

  8. Loading atom lasers by collectivity-enhanced optical pumping

    SciTech Connect (OSTI)

    Macovei, Mihai A.; Evers, Joerg [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

    2010-01-15T23:59:59.000Z

    The effect of collectivity on the loading of an atom laser via optical pumping is discussed. In our model, atoms in a beam are laser-excited and subsequently spontaneously decay into a trapping state. We consider the case of sufficiently high particle density in the beam such that the spontaneous emission is modified by the particle interaction. We show that the collective effects lead to a better population of the trapping state over a wide range of system parameters, and that the second-order correlation function of the atoms can be controlled by the applied laser field.

  9. Metal atomization spray nozzle

    DOE Patents [OSTI]

    Huxford, T.J.

    1993-11-16T23:59:59.000Z

    A spray nozzle for a magnetohydrodynamic atomization apparatus has a feed passage for molten metal and a pair of spray electrodes mounted in the feed passage. The electrodes, diverging surfaces which define a nozzle throat and diverge at an acute angle from the throat. Current passes through molten metal when fed through the throat which creates the Lorentz force necessary to provide atomization of the molten metal. 6 figures.

  10. Atomizing nozzle and method

    DOE Patents [OSTI]

    Ting, Jason (Ames, IA); Anderson, Iver E. (Ames, IA); Terpstra, Robert L. (Ames, IA)

    2000-03-16T23:59:59.000Z

    A high pressure close-coupled gas atomizing nozzle includes multiple discrete gas jet discharge orifices having aerodynamically designed convergent-divergent geometry with an first converging section communicated to a gas supply manifold and to a diverging section by a constricted throat section to increase atomizing gas velocity. The gas jet orifices are oriented at gas jet apex angle selected relative to the melt supply tip apex angle to establish a melt aspiration condition at the melt supply tip.

  11. Optical atomic magnetometer

    DOE Patents [OSTI]

    Budker, Dmitry; Higbie, James; Corsini, Eric P

    2013-11-19T23:59:59.000Z

    An optical atomic magnetometers is provided operating on the principles of nonlinear magneto-optical rotation. An atomic vapor is optically pumped using linearly polarized modulated light. The vapor is then probed using a non-modulated linearly polarized light beam. The resulting modulation in polarization angle of the probe light is detected and used in a feedback loop to induce self-oscillation at the resonant frequency.

  12. Epitaxial ferromagnetic oxide thin films on silicon with atomically sharp interfaces

    SciTech Connect (OSTI)

    Coux, P. de [Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Barcelona (Spain); CEMES-CNRS, 29 rue Jeanne Marvig, BP 94347, Toulouse Cedex 4 (France); Bachelet, R.; Fontcuberta, J.; Sánchez, F., E-mail: fsanchez@icmab.es [Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Barcelona (Spain); Warot-Fonrose, B. [CEMES-CNRS, 29 rue Jeanne Marvig, BP 94347, Toulouse Cedex 4 (France); Skumryev, V. [Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain and Dep. de Física, Univ. Autònoma de Barcelona, 08193 Bellaterra (Spain); Lupina, L.; Niu, G.; Schroeder, T. [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany)

    2014-07-07T23:59:59.000Z

    A bottleneck in the integration of functional oxides with silicon, either directly grown or using a buffer, is the usual formation of an amorphous interfacial layer. Here, we demonstrate that ferromagnetic CoFe{sub 2}O{sub 4} films can be grown epitaxially on Si(111) using a Y{sub 2}O{sub 3} buffer layer, and remarkably the Y{sub 2}O{sub 3}/Si(111) interface is stable and remains atomically sharp. CoFe{sub 2}O{sub 4} films present high crystal quality and high saturation magnetization.

  13. Atomic mass compilation 2012

    SciTech Connect (OSTI)

    Pfeiffer, B., E-mail: bpfeiffe@uni-mainz.de [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Venkataramaniah, K. [Sri Sathya Sai Institute of Higher Learning, Prasanthinilayam (India)] [Sri Sathya Sai Institute of Higher Learning, Prasanthinilayam (India); Czok, U. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, Gießen (Germany)] [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, Gießen (Germany); Scheidenberger, C. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany) [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); II. Physikalisches Institut, Justus-Liebig-Universität Gießen, Gießen (Germany)

    2014-03-15T23:59:59.000Z

    Atomic mass reflects the total binding energy of all nucleons in an atomic nucleus. Compilations and evaluations of atomic masses and derived quantities, such as neutron or proton separation energies, are indispensable tools for research and applications. In the last decade, the field has evolved rapidly after the advent of new production and measuring techniques for stable and unstable nuclei resulting in substantial ameliorations concerning the body of data and their precision. Here, we present a compilation of atomic masses comprising the data from the evaluation of 2003 as well as the results of new measurements performed. The relevant literature in refereed journals and reports as far as available, was scanned for the period beginning 2003 up to and including April 2012. Overall, 5750 new data points have been collected. Recommended values for the relative atomic masses have been derived and a comparison with the 2003 Atomic Mass Evaluation has been performed. This work has been carried out in collaboration with and as a contribution to the European Nuclear Structure and Decay Data Network of Evaluations.

  14. Ultra wide-bandwidth micro energy harvester

    E-Print Network [OSTI]

    Hajati, Arman

    2011-01-01T23:59:59.000Z

    An ultra wide-bandwidth resonating thin film PZT MEMS energy harvester has been designed, modeled, fabricated and tested. It harvests energy from parasitic ambient vibration at a wide range of amplitude and frequency via ...

  15. Effect of impurities and stress on the damage distributions of rapidly grown KDP crystals

    SciTech Connect (OSTI)

    Runkel, M.; Tan, M.; De Yoreo, J.; Zaitseva, N.

    1997-12-20T23:59:59.000Z

    Development of high damage threshold, 50 cm, rapidly grown KF*P frequency triplers for operation of the National Ignition Facility (NIF) in the 14 J/cm2, 351 nm, 3 ns regime requires a thorough understanding of how the crystal growth parameters and technologies affect laser induced damage. Of particular importance is determining the effect of ionic impurities (e.g. Cr3+, Fe3+, Al3+) which may be introduced in widely varying concentrations via starting salts. In addition, organic particulates can contaminate the solution as leachants from growth platforms or via mechanical ablation. Mechanical stresses in the crystals may also play a strong role in the laser-induced damage distribution (LIDD), particularly in the cases of large boules where hydrodynamic forces in the growth tank may be quite high. WE have developed a dedicated, automated damage test system with diagnostic capabilities specifically designed for measured time resolved bulk damage onset and evolution. The data obtained make it possible to construct characteristic damage threshold distributions for each sample. Test results obtained for a variety of KDP samples grown from high purity starting salts and individually doped with Lucite and Teflon, iron, chromium, and aluminium show that the LIDD drops with increasing contamination content. The results also show that solution filtration leads to increased damage performance for undoped crystals but is not solely responsibility for producing the high LIDDs required by the NIF. The highest LIDD measured on a rapidly grown sample indicate that it is possible to produce high damage threshold material using ultrahigh purity, recrystallized starting salts, continuous filtration and a platform designed to minimize internal stress during growth.

  16. Universal bosonic tetramers of dimer-atom-atom structure

    E-Print Network [OSTI]

    A. Deltuva

    2012-03-28T23:59:59.000Z

    Unstable four-boson states having an approximate dimer-atom-atom structure are studied using momentum-space integral equations for the four-particle transition operators. For a given Efimov trimer the universal properties of the lowest associated tetramer are determined. The impact of this tetramer on the atom-trimer and dimer-dimer collisions is analyzed. The reliability of the three-body dimer-atom-atom model is studied.

  17. Universal bosonic tetramers of dimer-atom-atom structure

    E-Print Network [OSTI]

    Deltuva, A

    2012-01-01T23:59:59.000Z

    Unstable four-boson states having an approximate dimer-atom-atom structure are studied using momentum-space integral equations for the four-particle transition operators. For a given Efimov trimer the universal properties of the lowest associated tetramer are determined. The impact of this tetramer on the atom-trimer and dimer-dimer collisions is analyzed. The reliability of the three-body dimer-atom-atom model is studied.

  18. X-ray magnetic circular dichroism for Co{sub x}Fe{sub 4?x}N (x?=?0, 3, 4) films grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Ito, Keita; Sanai, Tatsunori; Yasutomi, Yoko; Toko, Kaoru; Suemasu, Takashi, E-mail: suemasu@bk.tsukuba.ac.jp [Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Zhu, Siyuan; Kimura, Akio [Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Takeda, Yukiharu; Saitoh, Yuji [Condensed Matter Science Division, Japan Atomic Energy Agency, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5148 (Japan)

    2014-05-07T23:59:59.000Z

    We evaluated orbital (m{sub orb}) and spin magnetic moments (m{sub spin}) of Co{sub x}Fe{sub 4?x}N (x?=?0, 3, 4) epitaxial thin films grown by molecular beam epitaxy using x-ray magnetic circular dichroism, and discussed the dependence of these values on x. Site-averaged m{sub spin} value of Fe atoms was deduced to be 1.91??{sub B} per atom, and that of Co atoms to be 1.47??{sub B} per atom in Co{sub 3}FeN at 300?K. These values are close to 1.87??{sub B} per Fe atom in Fe{sub 4}N and 1.43??{sub B} per Co atom in Co{sub 4}N, respectively. This result implies that the Fe and Co atoms in the Co{sub 3}FeN films were located both at corner and face-centered sites in the anti-perovskite lattice. Spin magnetic moments per unit cell were decreased linearly with increasing x in Co{sub x}Fe{sub 4?x}N. This tendency is in good agreement with theory predicted by the first-principle calculation.

  19. Shock initiation experiments on ratchet grown PBX 9502

    SciTech Connect (OSTI)

    Gustavsen, Richard L [Los Alamos National Laboratory; Thompson, Darla G [Los Alamos National Laboratory; Olinger, Barton W [Los Alamos National Laboratory; Deluca, Racci [Los Alamos National Laboratory; Bartram, Brian D [Los Alamos National Laboratory; Pierce, Timothy H [Los Alamos National Laboratory; Sanchez, Nathaniel J [Los Alamos National Laboratory

    2010-01-01T23:59:59.000Z

    This study compares the shock initiation behavior of PBX 9502 pressed to less than nominal density (nominal density is 1.890 {+-} 0.005 g/cm{sup 3}) with PBX 9502 pressed to nominal density and then ''ratchet grown'' to low density. PBX 9502 is an insensitive plastic bonded explosive consisting of 95 weight % dry-aminated tri-amino-tri-nitro-benzene (TATB) and 5 weight % Kel-F 800 plastic binder. ''Ratchet growth'' - an irreversible increase in specific volume - occurs when an explosive based on TATB is temperature cycled. The design of our study is as follows: PBX 9502, all from the same lot, received the following four treatments. Samples in the first group were pressed to less than nominal density. These were not ratchet grown and used as a baseline. Samples in the second group were pressed to nominal density and then ratchet grown by temperature cycling 30 times between -54 C and +80 C. Samples in the final group were pressed to nominal density and cut into 100 mm by 25.4 mm diameter cylinders. During thermal cycling the cylinders were axially constrained by a 100 psi load. Samples for shock initiation experiments were cut perpendicular (disks) and parallel (slabs) to the axial load. The four sample groups can be summarized with the terms pressed low, ratchet grown/no load, axial load/disks, and axial load/slabs. All samples were shock initiated with nearly identical inputs in plate impact experiments carried out on a gas gun. Wave profiles were measured after propagation through 3, 4, 5, and 6 mm of explosive. Side by side comparison of wave profiles from different samples is used as a measure of relative sensitivity. All reduced density samples were more shock sensitive than nominal density PBX 9502. Differences in shock sensitivity between ratchet grown and pressed to low density PBX 9502 were small, but the low density pressings are slightly more sensitive than the ratchet grown samples.

  20. Substrate Atomic-Termination-Induced Anisotropic Growth of ZnO Nanowires/Nanorods by the VLS Process

    E-Print Network [OSTI]

    Wang, Zhong L.

    Substrate Atomic-Termination-Induced Anisotropic Growth of ZnO Nanowires/Nanorods by the VLSO substrate, we demonstrate the effect of substrate surface termination on nanowire growth. Symmetric) substrates have asymmetrically grown nanostructures. For the Zn-terminated (0001) substrate surface, uniform

  1. Experimental phasing for structure determination using membrane-protein crystals grown by the lipid cubic phase method

    SciTech Connect (OSTI)

    Li, Dianfan; Pye, Valerie E.; Caffrey, Martin, E-mail: martin.caffrey@tcd.ie [Trinity College Dublin, Dublin (Ireland)

    2015-01-01T23:59:59.000Z

    Very little information is available in the literature concerning the experimental heavy-atom phasing of membrane-protein structures where the crystals have been grown using the lipid cubic phase (in meso) method. In this paper, pre-labelling, co-crystallization, soaking, site-specific mercury binding to genetically engineered single-cysteine mutants and selenomethionine labelling as applied to an integral membrane kinase crystallized in meso are described. An assay to assess cysteine accessibility for mercury labelling of membrane proteins is introduced. Despite the marked increase in the number of membrane-protein structures solved using crystals grown by the lipid cubic phase or in meso method, only ten have been determined by SAD/MAD. This is likely to be a consequence of the technical difficulties associated with handling proteins and crystals in the sticky and viscous hosting mesophase that is usually incubated in glass sandwich plates for the purposes of crystallization. Here, a four-year campaign aimed at phasing the in meso structure of the integral membrane diacylglycerol kinase (DgkA) from Escherichia coli is reported. Heavy-atom labelling of this small hydrophobic enzyme was attempted by pre-labelling, co-crystallization, soaking, site-specific mercury binding to genetically engineered single-cysteine mutants and selenomethionine incorporation. Strategies and techniques for special handling are reported, as well as the typical results and the lessons learned for each of these approaches. In addition, an assay to assess the accessibility of cysteine residues in membrane proteins for mercury labelling is introduced. The various techniques and strategies described will provide a valuable reference for future experimental phasing of membrane proteins where crystals are grown by the lipid cubic phase method.

  2. Atomic Force Microscope

    SciTech Connect (OSTI)

    Day, R.D.; Russell, P.E.

    1988-12-01T23:59:59.000Z

    The Atomic Force Microscope (AFM) is a recently developed instrument that has achieved atomic resolution imaging of both conducting and non- conducting surfaces. Because the AFM is in the early stages of development, and because of the difficulty of building the instrument, it is currently in use in fewer than ten laboratories worldwide. It promises to be a valuable tool for obtaining information about engineering surfaces and aiding the .study of precision fabrication processes. This paper gives an overview of AFM technology and presents plans to build an instrument designed to look at engineering surfaces.

  3. Iowa Powder Atomization Technologies

    ScienceCinema (OSTI)

    None

    2013-03-01T23:59:59.000Z

    The same atomization effect seen in a fuel injector is being applied to titanium metal resulting in fine titanium powders that are less than half the width of a human hair. Titanium melts above 3,000°F and is highly corrosive therefore requiring specialized containers. The liquid titanium is poured through an Ames Laboratory - USDOE patented tube which is intended to increase the energy efficiency of the atomization process, which has the ability to dramatically decrease the cost of fine titanium powders. This novel process could open markets for green manufacturing of titanium components from jet engines to biomedical implants.

  4. Iowa Powder Atomization Technologies

    SciTech Connect (OSTI)

    None

    2012-01-01T23:59:59.000Z

    The same atomization effect seen in a fuel injector is being applied to titanium metal resulting in fine titanium powders that are less than half the width of a human hair. Titanium melts above 3,000°F and is highly corrosive therefore requiring specialized containers. The liquid titanium is poured through an Ames Laboratory - USDOE patented tube which is intended to increase the energy efficiency of the atomization process, which has the ability to dramatically decrease the cost of fine titanium powders. This novel process could open markets for green manufacturing of titanium components from jet engines to biomedical implants.

  5. Chiral meta-atoms rotated by light

    SciTech Connect (OSTI)

    Liu Mingkai; Powell, David A.; Shadrivov, Ilya V. [Nonlinear Physics Centre, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia)

    2012-07-16T23:59:59.000Z

    We study the opto-mechanical properties of coupled chiral meta-atoms based on a pair of twisted split-ring resonators. By using a simple analytical model in conjunction with the Maxwell stress tensor, we capture insight into the mechanism and find that this structure can be used as a general prototype of subwavelength light-driven actuators over a wide range of frequencies. This coupled structure can provide a strong and tunable torque, and can support different opto-mechanical modes, including uniform rotation, periodically variable rotation and damped oscillations. Our results suggest that chiral meta-atoms are good candidates for creating sub-wavelength motors or wrenches controlled by light.

  6. Highly c-axis oriented growth of GaN film on sapphire (0001) by laser molecular beam epitaxy using HVPE grown GaN bulk target

    SciTech Connect (OSTI)

    Kushvaha, S. S.; Kumar, M. Senthil; Maurya, K. K.; Dalai, M. K.; Sharma, Nita D. [CSIR-National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi, India 110012 (India)] [CSIR-National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi, India 110012 (India)

    2013-09-15T23:59:59.000Z

    Growth temperature dependant surface morphology and crystalline properties of the epitaxial GaN layers grown on pre-nitridated sapphire (0001) substrates by laser molecular beam epitaxy (LMBE) were investigated in the range of 500–750 °C. The grown GaN films were characterized using high resolution x-ray diffraction, atomic force microscopy (AFM), micro-Raman spectroscopy, and secondary ion mass spectroscopy (SIMS). The x-ray rocking curve full width at a half maximum (FWHM) value for (0002) reflection dramatically decreased from 1582 arc sec to 153 arc sec when the growth temperature was increased from 500 °C to 600 °C and the value further decreased with increase of growth temperature up to 720 °C. A highly c-axis oriented GaN epitaxial film was obtained at 720 °C with a (0002) plane rocking curve FWHM value as low as 102 arc sec. From AFM studies, it is observed that the GaN grain size also increased with increasing growth temperature and flat, large lateral grains of size 200-300 nm was obtained for the film grown at 720 °C. The micro-Raman spectroscopy studies also exhibited the high-quality wurtzite nature of GaN film grown on sapphire at 720 °C. The SIMS measurements revealed a non-traceable amount of background oxygen impurity in the grown GaN films. The results show that the growth temperature strongly influences the surface morphology and crystalline quality of the epitaxial GaN films on sapphire grown by LMBE.

  7. Original article Foliar senescence in maize plants grown

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Original article Foliar senescence in maize plants grown under different water regimes Arturo) Abstract - The leaf ontogeny of potted maize plants subjected to severe water stress was carried out and water-stressed plants received 100 and 50 % of the water evapotranspired, respectively. After 30 days

  8. Atomic Data for Fusion, Volumes 1, 3, 4, and 5: The ORNL CFADC Redbooks

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

    Barnett, C.F.; Thomas, E.W.; Wiese, W.L.; Phaneuf, R.A.; Janev, R.K.; Pindzola, M.S.

    This location provides on-line, full-text versions of the most recent and most widely requested CFADC series of volumes ( Atomic Data for Fusion ) containing recommended data for certain fusion relevant atomic collision processes. this website also provides a title list of all the CFADC published Redbooks.

  9. An Atom-Wide Antennae Created from Difference-Making Defects | Department

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33Frequently20,000 Russian NuclearandJune 17,Agenda Agenda Agenda4 Image:1 of 9 Nordex USAof

  10. DFAS Wide-Area Workflow Issues

    Broader source: Energy.gov [DOE]

    Presentation covers the DFAS wide-area workflow issues and is given at the Spring 2011 Federal Utility Partnership Working Group (FUPWG) meeting.

  11. Elements & Compounds Atoms (Elements)

    E-Print Network [OSTI]

    Frey, Terry

    #12;Elements & Compounds #12;Atoms (Elements) Molecules (Compounds) Cells Elements & Compounds #12 #12;First shell Second shell Third shell Hydrogen 1H Lithium 3Li Sodium 11Na Beryllium 4Be Magnesium energy Higher energy (a) A ball bouncing down a flight of stairs provides an analogy for energy levels

  12. SiGe quantum dot molecules grown on patterned Si (001) substrates

    SciTech Connect (OSTI)

    Yang Hongbin; Zhang Xiangjiu; Jiang Zuiming; Yang Xinju; Fan Yongliang [Surface Physics Laboratory (National Key Laboratory), Fudan University, Shanghai 200433 (China)

    2008-08-15T23:59:59.000Z

    SiGe quantum dot molecules (QDMs) grown on patterned Si (001) substrates by molecular beam epitaxy were studied. Experimental results showed that the density, the dimension, and the dimension distribution of the SiGe QDMs grown in the windows were dependent on the window size. When the thickness of the Si{sub 0.8}Ge{sub 0.2} film was 40 nm, QDMs only appeared in the unpatterned areas of the Si substrate and none could be found inside the windows of 6x6 {mu}m{sup 2} on the same substrate. However, when the thickness of Si{sub 0.8}Ge{sub 0.2} film was increased to 80 nm, QDMs appeared both inside the windows and in the unpatterned areas, and the density of QDMs was reduced with the decrease in the window size. We attribute these results to the different strain relaxations in different size windows, which are caused by the edge effect of the epitaxial film in the window. Based on these experimental results we discuss the formation and the size stability of the QDMs and conclude that the formation of the SiGe QDM originates from an intrinsic cause of the strain relief mechanism. This work also shows that by means of the edge induced strain relaxation of the epitaxial film in the window, it is possible to reveal the influence of the strain on some physical properties of the SiGe film without changing its Ge atomic fraction.

  13. Atom-by-atom nucleation and growth of graphene nanopores

    E-Print Network [OSTI]

    Golovchenko, Jene A.

    Atom-by-atom nucleation and growth of graphene nanopores Christopher J. Russoa,b and J. A February 17, 2012 (received for review December 9, 2011) Graphene is an ideal thin membrane substrate structures in graphene with atomic preci- sion. It consists of inducing defect nucleation centers with ener

  14. Effective Community-Wide Policy Technical Assistance

    E-Print Network [OSTI]

    Effective Community-Wide Policy Technical Assistance: The DOE/NREL Approach NREL is a national: The DOE/NREL Approach Effective Community-Wide Policy Technical Assistance: The DOE/NREL Approach HelpingVoss, Sarah Busche, Eric Lantz, Lynn Billman, and Dan Beckley. The layout and technical editing were

  15. Atomic phenomena in dense plasmas

    SciTech Connect (OSTI)

    Weisheit, J.C.

    1981-03-01T23:59:59.000Z

    The following chapters are included: (1) the plasma environment, (2) perturbations of atomic structure, (3) perturbations of atomic collisions, (4) formation of spectral lines, and (5) dielectronic recombination. (MOW)

  16. atoms: Topics by E-print Network

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

    with atomic and molecular matter waves is a rich branch of atomic physics and quantum optics. It started with atom diffraction from crystal surfaces and the separated oscillatory...

  17. Probing Atomic Structure and Majorana Wavefunctions in Mono-Atomic Fe-chains on Superconducting Pb-Surface

    E-Print Network [OSTI]

    Pawlak, Remy; Klinovaja, Jelena; Meier, Tobias; Kawai, Shigeki; Glatzel, Thilo; Loss, Daniel; Meyer, Ernst

    2015-01-01T23:59:59.000Z

    Motivated by the striking promise of quantum computation, Majorana bound states (MBSs) in solid-state systems have attracted wide attention in recent years. In particular, the wavefunction localization of MBSs is a key feature and crucial for their future implementation as qubits. Here, we investigate the spatial and electronic characteristics of topological superconducting chains of iron atoms on the surface of Pb(110) by combining scanning tunneling microscopy (STM) and atomic force microscopy (AFM). We demonstrate that the Fe chains are mono-atomic, structured in a linear fashion, and exhibit zero-bias conductance peaks at their ends which we interprete as signature for a Majorana bound state. Spatially resolved conductance maps of the atomic chains reveal that the MBSs are well localized at the chain ends (below 25 nm), with two localization lengths as predicted by theory. Our observation lends strong support to use MBSs in Fe chains as qubits for quantum computing devices.

  18. Calibration of a single atom detector for atomic micro chips

    E-Print Network [OSTI]

    A. Stibor; S. Kraft; T. Campey; D. Komma; A. Günther; J. Fortágh; C. J. Vale; H. Rubinsztein-Dunlop; C. Zimmermann

    2007-02-13T23:59:59.000Z

    We experimentally investigate a scheme for detecting single atoms magnetically trapped on an atom chip. The detector is based on the photoionization of atoms and the subsequent detection of the generated ions. We describe the characterization of the ion detector with emphasis on its calibration via the correlation of ions with simultaneously generated electrons. A detection efficiency of 47.8% (+-2.6%) is measured, which is useful for single atom detection, and close to the limit allowing atom counting with sub-Poissonian uncertainty.

  19. A microfabricated atomic clock

    SciTech Connect (OSTI)

    Knappe, Svenja; Shah, Vishal; Schwindt, Peter D.D.; Hollberg, Leo; Kitching, John; Liew, Li-Anne; Moreland, John [Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado 80305-3328 (United States); Electromagnetics Division, National Institute of Standards and Technology, Boulder, Colorado 80305-3328 (United States)

    2004-08-30T23:59:59.000Z

    Fabrication techniques usually applied to microelectromechanical systems (MEMS) are used to reduce the size and operating power of the core physics assembly of an atomic clock. With a volume of 9.5 mm{sup 3}, a fractional frequency instability of 2.5x10{sup -10} at 1 s of integration, and dissipating less than 75 mW of power, the device has the potential to bring atomically precise timing to hand-held, battery-operated devices. In addition, the design and fabrication process allows for wafer-level assembly of the structures, enabling low-cost mass-production of thousands of identical units with the same process sequence, and easy integration with other electronics.

  20. Delay in Atomic Photoionization

    SciTech Connect (OSTI)

    Kheifets, A. S. [Research School of Physical Sciences, Australian National University, Canberra ACT 0200 (Australia); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106-4030 (United States); Ivanov, I. A. [Research School of Physical Sciences, Australian National University, Canberra ACT 0200 (Australia)

    2010-12-03T23:59:59.000Z

    We analyze the time delay between emission of photoelectrons from the outer valence ns and np subshells in noble gas atoms following absorption of an attosecond extreme ultraviolet pulse. Various processes such as elastic scattering of the photoelectron on the parent ion and many-electron correlation affect the apparent 'time zero' when the photoelectron leaves the atom. This qualitatively explains the time delay between photoemission from the 2s and 2p subshells of Ne as determined experimentally by attosecond streaking [Science 328, 1658 (2010)]. However, with our extensive numerical modeling, we were only able to account for less than half of the measured time delay of 21{+-}5 as. We argue that the extreme ultraviolet pulse alone cannot produce such a large time delay and it is the streaking IR field that is most likely responsible for this effect.

  1. Influence of oxygen pressure and aging on LaAlO{sub 3} films grown by pulsed laser deposition on SrTiO{sub 3} substrates

    SciTech Connect (OSTI)

    Park, Jihwey; Aeppli, Gabriel [London Centre for Nanotechnology, University College London, London WC1H 0AH (United Kingdom); Soh, Yeong-Ah, E-mail: yeongahsoh@gmail.com [London Centre for Nanotechnology, University College London, London WC1H 0AH (United Kingdom); Department of Materials, Imperial College London, London SW7 2AZ (United Kingdom); David, Adrian; Lin, Weinan [Division of Physics and Applied Physics, Nanyang Technological University, Singapore 637371 (Singapore); Wu, Tom [Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia)

    2014-02-24T23:59:59.000Z

    The crystal structures of LaAlO{sub 3} films grown by pulsed laser deposition on SrTiO{sub 3} substrates at oxygen pressure of 10{sup ?3} millibars or 10{sup ?5} millibars, where kinetics of ablated species hardly depend on oxygen background pressure, are compared. Our results show that the interface between LaAlO{sub 3} and SrTiO{sub 3} is sharper when the oxygen pressure is lower. Over time, the formation of various crystalline phases is observed while the crystalline thickness of the LaAlO{sub 3} layer remains unchanged. X-ray scattering as well as atomic force microscopy measurements indicate three-dimensional growth of such phases, which appear to be fed from an amorphous capping layer present in as-grown samples.

  2. Thermoelectric properties of ZnSb films grown by MOCVD

    SciTech Connect (OSTI)

    Venkatasubramanian, R.; Watko, E.; Colpitts, T.

    1997-07-01T23:59:59.000Z

    The thermoelectric properties of ZnSb films grown by metallorganic chemical vapor deposition (MOCVD) are reported. The growth conditions necessary to obtain stoichiometric ZnSb films and the effects of various growth parameters on the electrical conductivity and Seebeck coefficients of the films are described. The as-grown ZnSb films are p-type. It was observed that the thicker ZnSb films offer improved carrier mobilities and lower free-carrier concentration levels. The Seebeck coefficient of ZnSb films was found to rise rapidly at approximately 160 C. The thicker films, due to the lower doping levels, indicate higher Seebeck coefficients between 25 to 200 C. A short annealing of the ZnSb film at temperatures of {approximately}200 C results in reduced free-carrier level. Thermal conductivity measurements of ZnSb films using the 3-{omega} method are also presented.

  3. Nano transfer and nanoreplication using deterministically grown sacrificial nanotemplates

    DOE Patents [OSTI]

    Melechko, Anatoli V. (Oak Ridge, TN); McKnight, Timothy E. (Greenback, TN); Guillorn, Michael A. (Ithaca, NY); Ilic, Bojan (Ithaca, NY); Merkulov, Vladimir I. (Knoxville, TX); Doktycz, Mitchel J. (Knoxville, TN); Lowndes, Douglas H. (Knoxville, TN); Simpson, Michael L. (Knoxville, TN)

    2012-03-27T23:59:59.000Z

    Methods, manufactures, machines and compositions are described for nanotransfer and nanoreplication using deterministically grown sacrificial nanotemplates. An apparatus, includes a substrate and a nanoconduit material coupled to a surface of the substrate. The substrate defines an aperture and the nanoconduit material defines a nanoconduit that is i) contiguous with the aperture and ii) aligned substantially non-parallel to a plane defined by the surface of the substrate.

  4. Atomic Inference from Weak Gravitational Lensing Data

    SciTech Connect (OSTI)

    Marshall, Phil; /KIPAC, Menlo Park

    2005-12-14T23:59:59.000Z

    We present a novel approach to reconstructing the projected mass distribution from the sparse and noisy weak gravitational lensing shear data. The reconstructions are regularized via the knowledge gained from numerical simulations of clusters, with trial mass distributions constructed from n NFW profile ellipsoidal components. The parameters of these ''atoms'' are distributed a priori as in the simulated clusters. Sampling the mass distributions from the atom parameter probability density function allows estimates of the properties of the mass distribution to be generated, with error bars. The appropriate number of atoms is inferred from the data itself via the Bayesian evidence, and is typically found to be small, reecting the quality of the data. Ensemble average mass maps are found to be robust to the details of the noise realization, and succeed in recovering the demonstration input mass distribution (from a realistic simulated cluster) over a wide range of scales. As an application of such a reliable mapping algorithm, we comment on the residuals of the reconstruction and the implications for predicting convergence and shear at specific points on the sky.

  5. West Wide Programmatic Environmental Impact Statement Record...

    Open Energy Info (EERE)

    Reference LibraryAdd to library Legal Document- OtherOther: West Wide Programmatic Environmental Impact Statement Record of Decision (BLM)Legal Published NA Year Signed or Took...

  6. GWIDD: Genome-wide protein docking database

    E-Print Network [OSTI]

    Kundrotas, Petras J.; Zhu, Zhengwei; Vasker, Ilya A.

    2009-11-09T23:59:59.000Z

    Structural information on interacting proteins is important for understanding life processes at the molecular level. Genome-wide docking database is an integrated resource for structural studies of protein–protein interactions on the genome scale...

  7. Optics and interferometry with atoms and molecules

    E-Print Network [OSTI]

    Cronin, Alexander D.

    Interference with atomic and molecular matter waves is a rich branch of atomic physics and quantum optics. It started with atom diffraction from crystal surfaces and the separated oscillatory fields technique used in atomic ...

  8. Analysis of CZT crystals and detectors grown in Russia and the Ukraine by high-pressure Bridgman methods

    SciTech Connect (OSTI)

    H. Hermon; M. Schieber; R. B. James; E. Y. Lee; N. Yang; A. J. Antolak; D. H. Morse; C. Hackett; E. Tarver; N. N. P. Kolesnikov; Yu N. Ivanov; V. Komar; M. S. Goorsky; H. Yoon

    2000-01-10T23:59:59.000Z

    Sandia National Laboratories (SNL) is leading an effort to evaluate vertical high pressure Bridgman (VHPB) Cd{sub 1-x}Zn{sub x}Te (CZT) crystals grown in the former Soviet Union (FSU) (Ukraine and Russia), in order to study the parameters limiting the crystal quality and the radiation detector performance. The stoichiometry of the CZT crystals, with 0.04 < x < 0.25, has been determined by methods such as proton-induced X-ray emission (PIXE), X-ray diffraction (XRD), microprobe analysis and laser ablation ICP mass spectroscopy (LA-ICP/MS). Other methods such as triaxial double crystal x-ray diffraction (TADXRD), infrared transmission spectroscopy (IR), atomic force microscopy (AFM), thermoelectric emission spectroscopy (TEES) and laser induced transient charge technique (TCT) were also used to evaluate the material properties. The authors have measured the zinc distribution in a CZT ingot along the axial direction and also its homogeneity. The (Cd+Zn)/Te average ratio measured on the Ukraine crystals was 1.2, compared to the ratio of 0.9-1.06 on the Russian ingots. The IR transmission showed highly decorated grain boundaries with precipitates and hollow bubbles. Microprobe elemental analysis and LA-ICP/MS showed carbon precipitates in the CZT bulk and carbon deposits along grain boundaries. The higher concentration of impurities and the imperfect crystallinity lead to shorter electron and hole lifetimes in the range of 0.5--2 {micro}s and 0.1 {micro}s respectively, compared to 3--20 {micro}s and 1--7 {micro}s measured on US spectrometer grade CZT detectors. These results are consistent with the lower resistivity and worse crystalline perfection of these crystals, compared to US grown CZT. However, recently grown CZT from FSU exhibited better detector performance and good response to alpha particles.

  9. Analysis of CZT crystals and detectors grown in Russia and the Ukraine by high-pressure Bridgman methods

    SciTech Connect (OSTI)

    Hermon, H.; Schieber, M. [Sandia National Labs., Livermore, CA (United States)]|[Hebrew Univ., Jerusalem (Israel); James, R.B. [Sandia National Labs., Livermore, CA (United States)] [and others

    1999-06-01T23:59:59.000Z

    Sandia National Laboratories (SNL) is leading an effort to evaluate vertical high pressure Bridgman (VHPB) Cd{sub 1{minus}x}Zn{sub x}Te (CZT) crystals grown in the former Soviet Union (FSU) (Ukraine and Russia), in order to study the parameters limiting the crystal quality and the radiation detector performance. The stoichiometry of the CZT crystals, with 0.04 < x < 0.25, has been determined by methods such as proton-induced x-ray emission (PIXE), x-ray diffraction (XRD), microprobe analysis and laser ablation ICP mass spectroscopy (LA-ICP/MS). Other methods such as triaxial double crystal x-ray diffraction (TADXRD), infrared transmission spectroscopy (IR), atomic force microscopy (AFM), thermoelectric emission spectroscopy (TEES) and laser induced transient charge technique (TCT) were also used to evaluate the material properties. The authors have measured the zinc distribution in a CZT ingot along the axial direction and also its homogeneity. The (Cd+Zn)/Te average ratio measured on the Ukraine crystals was 1.2, compared to the ratio of 0.9--1.06 on the Russian ingots. The IR transmission showed highly decorated grain boundaries with precipitates and hollow bubbles. Microprobe elemental analysis and LA-ICP/MS showed carbon precipitates in the CZT bulk and carbon deposits along grain boundaries. The higher concentration of impurities and the imperfect crystallinity lead to shorter electron and hole lifetimes in the range of 0.5--2 and 0.1 {micro}s, respectively, compared to 3--20 and 1--7 {micro}s measured on US spectrometer grade CZT detectors. These results are consistent with the lower resistivity and worse crystalline perfection of these crystals, compared to US-grown CZT. However, recently grown CZT from FSU exhibited better detector performance and good response to alpha particles.

  10. Atomic Collapse Observed

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisiting the TWP TWPAlumni AlumniFederalAshley BoyleAn overhead viewAtom-split it

  11. Built-in electric field in ZnO based semipolar quantum wells grown on (1012) ZnO substrates

    SciTech Connect (OSTI)

    Chauveau, J.-M.; Xia, Y.; Roland, B.; Vinter, B. [Centre de Recherche sur l'Hétéro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France) [Centre de Recherche sur l'Hétéro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France); University of Nice Sophia Antipolis, Parc Valrose, F-06102 Nice Cedex 2 (France); Ben Taazaet-Belgacem, I.; Teisseire, M.; Nemoz, M.; Brault, J.; Damilano, B.; Leroux, M. [Centre de Recherche sur l'Hétéro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France)] [Centre de Recherche sur l'Hétéro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France)

    2013-12-23T23:59:59.000Z

    We report on the properties of semipolar (Zn,Mg)O/ZnO quantum wells homoepitaxially grown by molecular beam epitaxy on (1012) R-plane ZnO substrates. We demonstrate that atomically flat interfaces can be achieved with fully relaxed quantum wells because the mismatch between (Zn,Mg)O and ZnO is minimal for this growth orientation. The photoluminescence properties evidence a quantum confined Stark effect with an internal electric field estimated to 430 kV/cm for a 17% Mg content in the barriers. The quantum well emission is strongly polarized along the 1210 direction and a comparison with the semipolar bulk ZnO luminescence polarization points to the effect of the confinement.

  12. High quality InAlN single layers lattice-matched to GaN grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Gacevic, Z.; Fernandez-Garrido, S.; Calleja, E. [ISOM, Universidad Politecnica de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain); Rebled, J. M.; Peiro, F. [LENS-MIND-IN2UB, Departament d'Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Estrade, S. [LENS-MIND-IN2UB, Departament d'Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); TEM-MAT, CCiT-UB, Sole i Sabaris 1, 08028 Barcelona (Spain)

    2011-07-18T23:59:59.000Z

    We report on properties of high quality {approx}60 nm thick InAlN layers nearly in-plane lattice-matched to GaN, grown on c-plane GaN-on-sapphire templates by plasma-assisted molecular beam epitaxy. Excellent crystalline quality and low surface roughness are confirmed by X-ray diffraction, transmission electron microscopy, and atomic force microscopy. High annular dark field observations reveal a periodic in-plane indium content variation (8 nm period), whereas optical measurements evidence certain residual absorption below the band-gap. The indium fluctuation is estimated to be {+-} 1.2% around the nominal 17% indium content via plasmon energy oscillations assessed by electron energy loss spectroscopy with sub-nanometric spatial resolution.

  13. Characterization of oxynitride dielectric films grown in NO/O{sub 2} mixtures by rapid thermal oxynitridation

    SciTech Connect (OSTI)

    EVERIST,SARAH C.; MEISENHEIMER,TIMOTHY L.; NELSON,GERALD C.; SMITH,PAUL M.

    2000-02-29T23:59:59.000Z

    Ultra-thin oxynitride films were grown on Si by direct rapid thermal processing (RTP) oxynitridation in NO/O{sub 2} ambients with NO concentrations from 5% to 50%. During oxynitridation, nitrogen accumulated at the Si/dielectric interface and the average concentration of in N through the resulting films ranged from 0.3 to 3.0 atomic percent. The average concentration of N in the films increased with increasing NO in the ambient gas, but decreased with longer RTP times. The maximum N concentration remained relatively constant for all RTP times and a given NO/O{sub 2} ambient. Re-oxidation following oxynitridation altered L the N profile and improved the electrical characteristics, with an optimal NO/O{sub 2} mixture in the range of 10% to 25% NO. Re-oxidation by RTP improves the electrical characteristics with respect to the films that were not re-oxidized and produces only slight changes in the N distribution or maximum concentration. The electrical results also indicate that oxynitride films are superior to comparably grown oxide films.

  14. Atomic Energy Commission Takes Over Responsibility for all Atomic...

    National Nuclear Security Administration (NNSA)

    Takes Over Responsibility for all Atomic Energy Programs | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the Stockpile...

  15. Quantum transport in ultracold atoms

    E-Print Network [OSTI]

    Chih-Chun Chien; Sebastiano Peotta; Massimiliano Di Ventra

    2015-04-11T23:59:59.000Z

    Ultracold atoms confined by engineered magnetic or optical potentials are ideal systems for studying phenomena otherwise difficult to realize or probe in the solid state because their atomic interaction strength, number of species, density, and geometry can be independently controlled. This review focuses on quantum transport phenomena in atomic gases that mirror and oftentimes either better elucidate or show fundamental differences with those observed in mesoscopic and nanoscopic systems. We discuss significant progress in performing transport experiments in atomic gases, contrast similarities and differences between transport in cold atoms and in condensed matter systems, and survey inspiring theoretical predictions that are difficult to verify in conventional setups. These results further demonstrate the versatility offered by atomic systems in the study of nonequilibrium phenomena and their promise for novel applications.

  16. The diameter of the world wide web

    E-Print Network [OSTI]

    Reka Albert; Hawoong Jeong; Albert-Laszlo Barabasi

    1999-09-10T23:59:59.000Z

    Despite its increasing role in communication, the world wide web remains the least controlled medium: any individual or institution can create websites with unrestricted number of documents and links. While great efforts are made to map and characterize the Internet's infrastructure, little is known about the topology of the web. Here we take a first step to fill this gap: we use local connectivity measurements to construct a topological model of the world wide web, allowing us to explore and characterize its large scale properties.

  17. Wide field imaging of distant clusters

    E-Print Network [OSTI]

    T. Treu

    2004-08-05T23:59:59.000Z

    Wide field imaging is key to understanding the build-up of distant clusters and their galaxy population. By focusing on the so far unexplored outskirts of clusters, where infalling galaxies first hit the cluster potential and the hot intracluster medium, we can help separate cosmological field galaxy evolution from that driven by environment. I present a selection of recent advancements in this area, with particular emphasis on Hubble Space Telescope wide field imaging, for its superior capability to deliver galaxy morphologies and precise shear maps of distant clusters.

  18. Unusual thermopower of inhomogeneous graphene grown by chemical vapor deposition

    SciTech Connect (OSTI)

    Nam, Youngwoo, E-mail: youngwoo.nam@chalmers.se [Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Sun, Jie; Lindvall, Niclas; Yurgens, August [Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Jae Yang, Seung; Rae Park, Chong [Department of Materials Science and Engineering, Seoul National University, Seoul 151-747 (Korea, Republic of); Woo Park, Yung [Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2014-01-13T23:59:59.000Z

    We report on thermopower (TEP) and resistance measurements of inhomogeneous graphene grown by chemical vapor deposition (CVD). Unlike the conventional resistance of pristine graphene, the gate-dependent TEP shows a large electron-hole asymmetry. This can be accounted for by inhomogeneity of the CVD-graphene where individual graphene regions contribute with different TEPs. At the high magnetic field and low temperature, the TEP has large fluctuations near the Dirac point associated with the disorder in the CVD-graphene. TEP measurements reveal additional characteristics of CVD-graphene, which are difficult to obtain from the measurement of resistance alone.

  19. Stresses in thermally grown alumina scales near edges and corners.

    SciTech Connect (OSTI)

    Grimsditch, M.

    1998-06-03T23:59:59.000Z

    We have investigated the residual stress near edges and corners of thermally grown alumina scales. Micro-fluorescence measurements, performed on alloys with composition Fe-5Cr-28Al (at.%, bal. Fe) oxidized at 900 C, showed a large (>50%) reduction in hydrostatic stress in the vicinity of edges and corners. Surprisingly, stress relaxation persists out to distances ten times the scale thickness from the edge. Finite element analysis calculations confirm the experimental results and provide a considerably more detailed picture of the stress distribution and its components.

  20. Transmittance from visible to mid infra-red in AZO films grown by atomic layer deposition system

    E-Print Network [OSTI]

    Tanner, David B.

    found applications in thin film photovoltaics such as CdTe and CIGS based solar cells (Dhere et al for solar cells, flat panel displays, LCD electrodes, touch panel transparent contacts and IR win- dows Westgate a , D.I. Koukis b , D.J. Arenas c , D.B. Tanner b a Center for Autonomous Solar Power, Binghamton

  1. Wide temperature range seal for demountable joints

    DOE Patents [OSTI]

    Sixsmith, H.; Valenzuela, J.A.; Nutt, W.E.

    1991-07-23T23:59:59.000Z

    The present invention is directed to a seal for demountable joints operating over a wide temperature range down to liquid helium temperatures. The seal has anti-extrusion guards which prevent extrusion of the soft ductile sealant material, which may be indium or an alloy thereof. 6 figures.

  2. Wide temperature range seal for demountable joints

    DOE Patents [OSTI]

    Sixsmith, Herbert (Norwich, VT); Valenzuela, Javier A. (Grantham, NH); Nutt, William E. (Enfield, NH)

    1991-07-23T23:59:59.000Z

    The present invention is directed to a seal for demountable joints operating over a wide temperature range down to liquid helium temperatures. The seal has anti-extrusion guards which prevent extrusion of the soft ductile sealant material, which may be indium or an alloy thereof.

  3. Coherent Atom Optics with fast metastable rare gas atoms

    SciTech Connect (OSTI)

    Grucker, J.; Baudon, J.; Karam, J.-C.; Perales, F.; Vassilev, G.; Ducloy, M. [Laboratoire de Physique des Lasers, Universite Paris 13, Avenue J.B. Clement, 93430-Villetaneuse (France); Bocvarski, V. [Institute of Physics, Pregrevica 118, 11080 - Belgrade-Zemun (Serbia and Montenegro)

    2006-12-01T23:59:59.000Z

    Coherent atom optics experiments making use of an ultra-narrow beam of fast metastable atoms generated by metastability exchange are reported. The transverse coherence of the beam (coherence radius of 1.7 {mu}m for He*, 1.2 {mu}m for Ne*, 0.87 {mu}m for Ar*) is demonstrated via the atomic diffraction by a non-magnetic 2{mu}m-period reflection grating. The combination of the non-scalar van der Waals (vdW) interaction with the Zeeman interaction generated by a static magnetic field gives rise to ''vdW-Zeeman'' transitions among Zeeman sub-levels. Exo-energetic transitions of this type are observed with Ne*(3P2) atoms traversing a copper micro-slit grating. They can be used as a tunable beam splitter in an inelastic Fresnel bi-prism atom interferometer.

  4. High electron mobility thin-film transistors based on Ga{sub 2}O{sub 3} grown by atmospheric ultrasonic spray pyrolysis at low temperatures

    SciTech Connect (OSTI)

    Thomas, Stuart R., E-mail: s.thomas09@imperial.ac.uk, E-mail: thomas.anthopoulos@imperial.ac.uk; Lin, Yen-Hung; Faber, Hendrik; Anthopoulos, Thomas D., E-mail: s.thomas09@imperial.ac.uk, E-mail: thomas.anthopoulos@imperial.ac.uk [Department of Physics, Blackett Laboratory, Imperial College London, London SW7 2BW (United Kingdom); Adamopoulos, George [Department of Engineering, Engineering Building, Lancaster University, Bailrigg, Lancaster LA1 4YR (United Kingdom); Sygellou, Labrini [Institute of Chemical Engineering and High Temperature Processes (ICEHT), Foundation of Research and Technology Hellas (FORTH), Stadiou Strasse Platani, P.O. Box 1414, Patras GR-265 04 (Greece); Stratakis, Emmanuel [Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion 71003 (Greece); Materials Science and Technology Department, University, of Crete, Heraklion 71003 (Greece); Pliatsikas, Nikos; Patsalas, Panos A. [Laboratory of Applied Physics, Department of Physics, Aristotle University of Thessaloniki, Thessaloniki GR-54124 (Greece)

    2014-09-01T23:59:59.000Z

    We report on thin-film transistors based on Ga{sub 2}O{sub 3} films grown by ultrasonic spray pyrolysis in ambient atmosphere at 400–450?°C. The elemental, electronic, optical, morphological, structural, and electrical properties of the films and devices were investigated using a range of complementary characterisation techniques, whilst the effects of post deposition annealing at higher temperature (700?°C) were also investigated. Both as-grown and post-deposition annealed Ga{sub 2}O{sub 3} films are found to be slightly oxygen deficient, exceptionally smooth and exhibit a wide energy bandgap of ?4.9?eV. Transistors based on as-deposited Ga{sub 2}O{sub 3} films show n-type conductivity with the maximum electron mobility of ?2?cm{sup 2}/V s.

  5. Bogoliubov theory and bosonic atoms

    E-Print Network [OSTI]

    Phan Thanh Nam

    2011-09-13T23:59:59.000Z

    We formulate the Bogoliubov variational principle in a mathematical framework similar to the generalized Hartree-Fock theory. Then we analyze the Bogoliubov theory for bosonic atoms in details. We discuss heuristically why the Bogoliubov energy should give the first correction to the leading energy of large bosonic atoms.

  6. Spectra of helium clusters with up to six atoms using soft core potentials

    E-Print Network [OSTI]

    M. Gattobigio; A. Kievsky; M. Viviani

    2011-12-01T23:59:59.000Z

    In this work we investigate small clusters of helium atoms using the hyperspherical harmonic basis. We consider systems with $A=2,3,4,5,6$ atoms with an inter-particle potential which does not present a strong repulsion at short distances. We use an attractive gaussian potential that reproduces the values of the dimer binding energy, the atom-atom scattering length, and the effective range obtained with one of the widely used He-He interactions, the LM2M2 potential. In systems with more than two atoms we consider a repulsive three-body force that, by construction, reproduces the trimer binding energy of the LM2M2 potential. With this model, consisting in the sum of a two- and three-body potential, we have calculated the spectrum of clusters formed by four, five and six helium atoms. We have found that these systems present two bound states, one deep and one shallow close to the threshold fixed by the energy of the $(A-1)$-atom system. Universal relations between the energies of the excited state of the $A$-atom system and the ground state energy of the $(A-1)$-atom system are extracted as well as the ratio between the ground state of the $A$-atom system and the ground state energy of the trimer.

  7. Spectra of helium clusters with up to six atoms using soft-core potentials

    SciTech Connect (OSTI)

    Gattobigio, M. [Universite de Nice-Sophia Antipolis, Institut Non-Lineaire de Nice, CNRS, 1361 route des Lucioles, F-06560 Valbonne (France); Kievsky, A.; Viviani, M. [Istituto Nazionale di Fisica Nucleare, Largo Pontecorvo 3, I-56100 Pisa (Italy)

    2011-11-15T23:59:59.000Z

    In this paper, we investigate small clusters of helium atoms using the hyperspherical harmonic basis. We consider systems with A=2,3,4,5,6 atoms with an interparticle potential which does not present a strong repulsion at short distances. We use an attractive Gaussian potential that reproduces the values of the dimer binding energy, the atom-atom scattering length, and the effective range obtained with one of the widely used He-He interactions, the Aziz and Slaman potential, called LM2M2. In systems with more than two atoms, we consider a repulsive three-body force that, by construction, reproduces the trimer binding energy of the LM2M2 potential. With this model, consisting of the sum of a two- and three-body potential, we have calculated the spectrum of clusters formed by four, five, and six helium atoms. We have found that these systems present two bound states, one deep and one shallow, close to the threshold fixed by the energy of the (A-1)-atom system. Universal relations between the energies of the excited state of the A-atom system and the ground-state energy of the (A-1)-atom system are extracted, as well as the ratio between the ground state of the A-atom system and the ground-state energy of the trimer.

  8. In-situ control system for atomization

    DOE Patents [OSTI]

    Anderson, I.E.; Figliola, R.S.; Terpstra, R.L.

    1995-06-13T23:59:59.000Z

    Melt atomizing apparatus comprising a melt supply orifice for supplying the melt for atomization and gas supply orifices proximate the melt supply orifice for supplying atomizing gas to atomize the melt as an atomization spray is disclosed. The apparatus includes a sensor, such as an optical and/or audio sensor, for providing atomization spray data, and a control unit responsive to the sensed atomization spray data for controlling at least one of the atomizing gas pressure and an actuator to adjust the relative position of the gas supply orifice and melt supply in a manner to achieve a desired atomization spray. 3 figs.

  9. Spectral Emission of Moving Atom

    E-Print Network [OSTI]

    J. X. Zheng-Johansson

    2008-03-17T23:59:59.000Z

    A renewed analysis of the H.E. Ives and G.R. Stilwell's experiment on moving hydrogen canal rays (J. Opt. Soc. Am., 1938, v.28, 215) concludes that the spectral emission of a moving atom exhibits always a redshift which informs not the direction of the atom's motion. The conclusion is also evident from a simple energy relation: atomic spectral radiation is emitted as an orbiting electron consumes a portion of its internal energy on transiting to a lower-energy state which however has in a moving atom an additional energy gain; this results in a redshift in the emission frequency. Based on auxiliary experimental information and a scheme for de Broglie particle formation, we give a vigorous elucidation of the mechanism for deceleration radiation of atomic electron; the corresponding prediction of the redshift is in complete agreement with the Ives and Stilwell's experimental formula.

  10. Atom-interferometry constraints on dark energy

    E-Print Network [OSTI]

    Hamilton, Paul; Haslinger, Philipp; Simmons, Quinn; Müller, Holger; Khoury, Justin

    2015-01-01T23:59:59.000Z

    If dark energy---which drives the accelerated expansion of the universe---consists of a new light scalar field, it might be detectable as a "fifth force" between normal-matter objects, in potential conflict with precision tests of gravity. There has, however, been much theoretical progress in developing theories with screening mechanisms, which can evade detection by suppressing forces in regions of high density, such as the laboratory. One prominent example is the chameleon field. We reduce the effect of this screening mechanism by probing the chameleon with individual atoms rather than bulk matter. Using a cesium matter-wave interferometer near a spherical mass in an ultra-high vacuum chamber, we constrain a wide class of dynamical dark energy theories. Our experiment excludes a range of chameleon theories that reproduce the observed cosmic acceleration.

  11. Supersonic coal water slurry fuel atomizer

    DOE Patents [OSTI]

    Becker, Frederick E. (Reading, MA); Smolensky, Leo A. (Concord, MA); Balsavich, John (Foxborough, MA)

    1991-01-01T23:59:59.000Z

    A supersonic coal water slurry atomizer utilizing supersonic gas velocities to atomize coal water slurry is provided wherein atomization occurs externally of the atomizer. The atomizer has a central tube defining a coal water slurry passageway surrounded by an annular sleeve defining an annular passageway for gas. A converging/diverging section is provided for accelerating gas in the annular passageway to supersonic velocities.

  12. WORLD WIDE WEB 2.3 Web

    E-Print Network [OSTI]

    Markatos, Evangelos P.

    H I2 C WORLD WIDE WEB 1996 #12; 1. 1.1 I2 Cnet 1.2 1.3 WWW 2 2.1 2.2 2.3 Web 2.4 3 O 3.1 3.2 3.3 3.4 O Web browsers. 4. 4.1 4.2 4 File System 9.6 10 A. Web browser HTT . B A #12

  13. World Wide Web( WWW ) Greenberg Web

    E-Print Network [OSTI]

    Shirai, Kiyoaki

    WWW 1 World Wide Web( WWW ) WWW Web Web Greenberg Web 30% [1] Web WWW Web WWW [2] [3] WWW 2 2.1 WWW Web 1 1: · 1 · 1 #12;· Web Web 2: 2 2 Web 2.2 Web Web URL URL .html / Yahoo http://headlines.yahoo.co.jp/hl?a=2 0011205-00000101-yom-soci URL onmouseover on- mouseout JavaScript 2.1 2.3 URL URL 1. Web HTML 2. 1

  14. Efficient Infrared-Emitting PbS Quantum Dots Grown on DNA and

    E-Print Network [OSTI]

    , the DNA-grown PbS nanocrystals exhibit a quantum-efficien- cy half-life of one week. We fabricate thin

  15. Coherent cooling of atoms in a frequency-modulated standing laser wave: Wave function and stochastic trajectory approaches

    SciTech Connect (OSTI)

    Argonov, V. Yu., E-mail: argonov@poi.dvo.ru [Russian Academy of Sciences, Pacific Oceanological Institute (Russian Federation)

    2014-11-15T23:59:59.000Z

    The wave function of a moderately cold atom in a stationary near-resonant standing light wave delocalizes very fast due to wave packet splitting. However, we show that frequency modulation of the field can suppress packet splitting for some atoms whose specific velocities are in a narrow range. These atoms remain localized in a small space for a long time. We demonstrate and explain this effect numerically and analytically. We also demonstrate that the modulated field can not only trap but also cool the atoms. We perform a numerical experiment with a large atomic ensemble having wide initial velocity and energy distributions. During the experiment, most of atoms leave the wave while the trapped atoms have a narrow energy distribution.

  16. Detection of transient fluorine atoms

    SciTech Connect (OSTI)

    Loge, G.W.; Nereson, N.; Fry, H.A.

    1986-01-01T23:59:59.000Z

    A KrF eximer laser with a fluence of 50 mJ/cm/sup 2/ was used to photolyze either uranium hexafluoride or molecular fluorine, yielding a transient number density of fluorine atoms. The rise and decay of the atomic fluorine density was observed by transient absorption of a 25-..mu..m Pb-salt diode laser. To prevent the diode laser wavelength from drifting out of resonance with the atomic fluorine line, part of the beam was split off and sent through a microwave discharge fluorine atom cell. This allowed a wavelength modulation-feedback technique to be used to lock the diode laser wavelength onto the atomic line. The remaining diode laser beam was made collinear with the eximer laser beam using a LiF window with a 45/sup 0/ angle of incidence to reflect the infrared beam while transmitting most of the uv beam. Using this setup along with a transient digitizer to average between 100 and 200 transient absorption profiles, fluorine atom number densities on the order of 10/sup 14/ cm/sup -3/ in a 1.7 m pathlength were detected. The signals observed were about a factor of two less than expected from known photolysis and atomic fluorine absorption cross-sections. 2 refs., 4 figs.

  17. Carbon nanotubes grown on bulk materials and methods for fabrication

    DOE Patents [OSTI]

    Menchhofer, Paul A. (Clinton, TN); Montgomery, Frederick C. (Oak Ridge, TN); Baker, Frederick S. (Oak Ridge, TN)

    2011-11-08T23:59:59.000Z

    Disclosed are structures formed as bulk support media having carbon nanotubes formed therewith. The bulk support media may comprise fibers or particles and the fibers or particles may be formed from such materials as quartz, carbon, or activated carbon. Metal catalyst species are formed adjacent the surfaces of the bulk support material, and carbon nanotubes are grown adjacent the surfaces of the metal catalyst species. Methods employ metal salt solutions that may comprise iron salts such as iron chloride, aluminum salts such as aluminum chloride, or nickel salts such as nickel chloride. Carbon nanotubes may be separated from the carbon-based bulk support media and the metal catalyst species by using concentrated acids to oxidize the carbon-based bulk support media and the metal catalyst species.

  18. Graphite Furnance Atomic Absorption as a detector for High Performance Liquid Chromatography

    E-Print Network [OSTI]

    Howell, Huston Edward

    1980-01-01T23:59:59.000Z

    tubing on peak broadening 38 Pulsed mode and uv chromatograms of two organo- selenium compounds 40 12. Pulsed mode and uv chromatograms of the organo- selenium compounds . . . . . . . . . . . . . . 41 13. An example of the variation of peak sizes... (8), flame and flameless atomic absorption (5), molecular (9) and atomic fluorescence (10), and electrochemical methods (11). By far the most widely used detection method for HPLC is ultraviolet (uv) absorption spectroscopy. The uv absorbance...

  19. Anticipating the atom: popular perceptions of atomic power before Hiroshima

    E-Print Network [OSTI]

    d'Emal, Jacques-Andre Christian

    1994-01-01T23:59:59.000Z

    Before Hiroshima made the Bomb an object of popular concern, possible implications and applications of atomic physics had been discussed in the public forum. The new science of X-rays and radium promised the possibilities of unlimited energy...

  20. atomization atomic absorption: Topics by E-print Network

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

    cells to modern observations of dust clouds in stellar nebulas and Bose-Einstein condensates. Here we show the first absorption imaging of a single atom isolated in vacuum. The...

  1. Chemical factors influencing selenium atomization

    E-Print Network [OSTI]

    Buren, Mary Sue

    1980-01-01T23:59:59.000Z

    Atomization. (August 1980) Mary Sue Buren, B, S. , Angelo State University Chairman of Advisory Comm1ttee: Dr. Thomas M. Vickrey Selenium in an acid1c matrix was analyzed using graphite furnace atom1c absorption with Zeeman-effect background correct1on.... Nickel(II} and lanthanum( III) were introduced as matrix modifiers to determine their effect on interferences 1n selenium atom1zation. In add1tion to matr1x mod1ficat1on, surface coating the graphite furnace with z1rconium and tantalum salts was also...

  2. Chemical factors influencing selenium atomization 

    E-Print Network [OSTI]

    Buren, Mary Sue

    1980-01-01T23:59:59.000Z

    Atomization. (August 1980) Mary Sue Buren, B, S. , Angelo State University Chairman of Advisory Comm1ttee: Dr. Thomas M. Vickrey Selenium in an acid1c matrix was analyzed using graphite furnace atom1c absorption with Zeeman-effect background correct1on.... Nickel(II} and lanthanum( III) were introduced as matrix modifiers to determine their effect on interferences 1n selenium atom1zation. In add1tion to matr1x mod1ficat1on, surface coating the graphite furnace with z1rconium and tantalum salts was also...

  3. Heterogeneous Catalysis on Atomically Dispersed Supported Metals...

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

    Catalysis on Atomically Dispersed Supported Metals: CO2 Reduction on Multifunctional Pd Catalysts. Heterogeneous Catalysis on Atomically Dispersed Supported Metals: CO2 Reduction...

  4. WIRELESS MINE-WIDE TELECOMMUNICATIONS TECHNOLOGY

    SciTech Connect (OSTI)

    Zvi H. Meiksin

    2004-03-01T23:59:59.000Z

    A comprehensive mine-wide, two-way wireless voice and data communication system for the underground mining industry was developed. The system achieves energy savings through increased productivity and greater energy efficiency in meeting safety requirements within mines. The mine-wide system is comprised of two interfaced subsystems: a through-the-earth communications system and an in-mine communications system. The mine-wide system permits two-way communication among underground personnel and between underground and surface personnel. The system was designed, built, and commercialized. Several systems are in operation in underground mines in the United States. The use of these systems has proven they result in considerable energy savings. A system for tracking the location of vehicles and people within the mine was also developed, built and tested successfully. Transtek's systems are being used by the National Institute of Occupational Safety and Health (NIOSH) in their underground mine rescue team training program. This project also resulted in a spin-off rescue team lifeline and communications system. Furthermore, the project points the way to further developments that can lead to a GPS-like system for underground mines allowing the use of autonomous machines in underground mining operations, greatly reducing the amount of energy used in these operations. Some products developed under this program are transferable to applications in fields other than mining. The rescue team system is applicable to use by first responders to natural, accidental, or terrorist-caused building collapses. The in-mine communications system can be installed in high-rise buildings providing in-building communications to security and maintenance personnel as well as to first responders.

  5. Epitaxial growth of AlN films via plasma-assisted atomic layer epitaxy

    SciTech Connect (OSTI)

    Nepal, N.; Qadri, S. B.; Hite, J. K.; Mahadik, N. A.; Mastro, M. A.; Eddy, C. R. Jr. [U.S. Naval Research Laboratory, Washington, DC 20375 (United States)] [U.S. Naval Research Laboratory, Washington, DC 20375 (United States)

    2013-08-19T23:59:59.000Z

    Thin AlN layers were grown at 200–650 °C by plasma assisted atomic layer epitaxy (PA-ALE) simultaneously on Si(111), sapphire (1120), and GaN/sapphire substrates. The AlN growth on Si(111) is self-limited for trimethyaluminum (TMA) pulse of length > 0.04 s, using a 10 s purge. However, the AlN nucleation on GaN/sapphire is non-uniform and has a bimodal island size distribution for TMA pulse of ?0.03 s. The growth rate (GR) remains almost constant for T{sub g} between 300 and 400 °C indicating ALE mode at those temperatures. The GR is increased by 20% at T{sub g} = 500 °C. Spectroscopic ellipsometry (SE) measurement shows that the ALE AlN layers grown at T{sub g} ? 400 °C have no clear band edge related features, however, the theoretically estimated band gap of 6.2 eV was measured for AlN grown at T{sub g} ? 500 °C. X-ray diffraction measurements on 37 nm thick AlN films grown at optimized growth conditions (T{sub g} = 500 °C, 10 s purge, 0.06 s TMA pulse) reveal that the ALE AlN on GaN/sapphire is (0002) oriented with rocking curve full width at the half maximum (FWHM) of 670 arc sec. Epitaxial growth of crystalline AlN layers by PA-ALE at low temperatures broadens application of the material in the technologies that require large area conformal growth at low temperatures with thickness control at the atomic scale.

  6. Modern testing meets wide range of objectives

    SciTech Connect (OSTI)

    Ehlig-Economides, C.A.; Hegeman, P. (Schlumberger Oilfield Services, Houston, TX (United States)); Clark, G. (Schlumberger Oilfield Services, Aberdeen (United Kingdom))

    1994-08-01T23:59:59.000Z

    Testing sequences in two very different wells illustrate the wide range of objectives that are met with modern testing procedures. The first example is a drill stem test in an exploration well. The second test is in an established producing well. The exploration well test incorporated tubing-conveyed perforating, fluid sampling, production logging, and matrix stimulation to evaluate and properly treat near-well bore damage, as well as to investigate reservoir volume and characterize boundaries. The test on the established producer evaluated whether a workover could remedy lower than expected productivity. Production logging was combined with stationary transient measurements.

  7. Concave nanomagnets with widely tunable anisotropy

    SciTech Connect (OSTI)

    Lambson, Brian; Gu, Zheng; Carlton, David; Bokor, Jeffrey

    2014-07-01T23:59:59.000Z

    A nanomagnet having widely tunable anisotropy is disclosed. The disclosed nanomagnet is a magnetic particle with a convex shape having a first magnetically easy axis. The convex shape is modified to include at least one concavity to urge a second magnetically easy axis to form substantially offset from the first magnetically easy axis. In at least one embodiment, the convex shape is also modified to include at least one concavity to urge a second magnetically easy axis to form with a magnetic strength substantially different from the first magnetically easy axis.

  8. Wide Bandgap Semiconductors: Pursuing the Promise

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradley NickellApril 16, 2008 TBD-0075 -In theWide Bandgap

  9. Draft Site-Wide Environmental Impact Statement

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 1112011AT&T,Office of Policy,Policy ActDetroit7471Site-Wide Environmental Impact Statement

  10. Wide Bandgap Semiconductors | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsingWhat is a “Shut-down”Whole AlgaeRateWhy IsWhyWhyWide

  11. Wide Electrochemical Window Solvents - Energy Innovation Portal

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsingWhat is a “Shut-down”Whole AlgaeRateWhyWide

  12. Imaging atoms in 3-D

    ScienceCinema (OSTI)

    Ercius, Peter

    2014-06-27T23:59:59.000Z

    Berkeley Lab's Peter Ercius discusses "Imaging atoms in 3-D" in this Oct. 28, 2013 talk, which is part of a Science at the Theater event entitled Eight Big Ideas

  13. Imaging atoms in 3-D

    SciTech Connect (OSTI)

    Ercius, Peter

    2013-10-31T23:59:59.000Z

    Berkeley Lab's Peter Ercius discusses "Imaging atoms in 3-D" in this Oct. 28, 2013 talk, which is part of a Science at the Theater event entitled Eight Big Ideas

  14. Lesson Learned by Environmental Management Complex-wide Activity...

    Broader source: Energy.gov (indexed) [DOE]

    Environmental Management Complex-wide Activity-level Work Planning and Control Lesson Learned by Environmental Management Complex-wide Activity-level Work Planning and Control...

  15. Networking and the Web World-Wide Web

    E-Print Network [OSTI]

    North Carolina at Chapel Hill, University of

    Networking and the Web #12;World-Wide Web · Wide use of computers Web · Key components of the web ­ Computer Communica8on Networks

  16. District Wide Geothermal Heating Conversion Blaine County School...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    District Wide Geothermal Heating Conversion Blaine County School District District Wide Geothermal Heating Conversion Blaine County School District This project will impact the...

  17. Mass Spectrometry Analysis of Proteome-wide Proteolytic Post...

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

    Spectrometry Analysis of Proteome-wide Proteolytic Post-translational Degradation of Proteins. Mass Spectrometry Analysis of Proteome-wide Proteolytic Post-translational...

  18. Effective Community-Wide Policy Technical Assistance: The NREL...

    Open Energy Info (EERE)

    Wide Policy Technical Assistance: The NRELDOE Approach Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Effective Community-Wide Policy Technical Assistance: The NREL...

  19. Proposed Energy Transport Corridors: West-wide energy corridor...

    Broader source: Energy.gov (indexed) [DOE]

    Energy Transport Corridors: West-wide energy corridor programmatic EIS, Draft Corridors - September 2007. Proposed Energy Transport Corridors: West-wide energy corridor...

  20. Webinar: Opportunities for Wide Bandgap Semiconductor Power Electronic...

    Broader source: Energy.gov (indexed) [DOE]

    Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications Webinar: Opportunities for Wide Bandgap Semiconductor Power Electronics...

  1. Recent Progress in ultracold atoms

    E-Print Network [OSTI]

    Baltisberger, Jay H.

    , cold gas experiments 2. How to make a BEC out of fermions 3. Recent Progress: Controlling Interaction (Feshbach Resonance) 4. From BCS to BEC: Rotating trap and spin- polarized condensates. 5. Future research and Einstein What is Bose-Einstein condensation (BEC)? #12;300 K to 1 mK 109 atoms 1 mK to 1 mK 108 106 atoms

  2. Absorption properties of identical atoms

    E-Print Network [OSTI]

    Pedro Sancho

    2013-07-31T23:59:59.000Z

    Emission rates and other optical properties of multiparticle systems in collective and entangled states differ from those in product ones. We show the existence of similar effects in the absorption probabilities for (anti)symmetrized states of two identical atoms. The effects strongly depend on the overlapping between the atoms and differ for bosons and fermions. We propose a viable experimental verification of these ideas.

  3. Wide Angle Effects in Galaxy Surveys

    E-Print Network [OSTI]

    Yoo, Jaiyul

    2013-01-01T23:59:59.000Z

    Current and future galaxy surveys cover a large fraction of the entire sky with a significant redshift range, and the recent theoretical development shows that general relativistic effects are present in galaxy clustering on very large scales. This trend has renewed interest in the wide angle effect in galaxy clustering measurements, in which the distant-observer approximation is often adopted. Using the full wide-angle formula for computing the redshift-space correlation function, we show that compared to the sample variance, the deviation in the redshift-space correlation function from the simple Kaiser formula with the distant-observer approximation is negligible in the SDSS and is completely irrelevant in future galaxy surveys such as Euclid and the BigBOSS, if the theoretical prediction from the Kaiser formula is averaged over the survey volume and the non-uniform distribution of cosine angle between the line-of-sight and the pair separation directions is properly considered. We also find small correctio...

  4. WIDE-FIELD ASTRONOMICAL MULTISCALE CAMERAS

    SciTech Connect (OSTI)

    Marks, Daniel L.; Brady, David J., E-mail: dbrady@ee.duke.edu [Department of Electrical and Computer Engineering and Fitzpatrick Institute for Photonics, Box 90291, Duke University, Durham, NC 27708 (United States)

    2013-05-15T23:59:59.000Z

    In order to produce sufficiently low aberrations with a large aperture, telescopes have a limited field of view. Because of this narrow field, large areas of the sky at a given time are unobserved. We propose several telescopes based on monocentric reflective, catadioptric, and refractive objectives that may be scaled to wide fields of view and achieve 1.''1 resolution, which in most locations is the practical seeing limit of the atmosphere. The reflective and Schmidt catadioptric objectives have relatively simple configurations and enable large fields to be captured at the expense of the obscuration of the mirror by secondary optics, a defect that may be managed by image plane design. The refractive telescope design does not have an obscuration but the objective has substantial bulk. The refractive design is a 38 gigapixel camera which consists of a single monocentric objective and 4272 microcameras. Monocentric multiscale telescopes, with their wide fields of view, may observe phenomena that might otherwise be unnoticed, such as supernovae, glint from orbital space debris, and near-earth objects.

  5. Oxidation and diffusion of Cu in SrS: Cu grown by MBE for blue phosphors

    E-Print Network [OSTI]

    Wang, Zhong L.

    Oxidation and diffusion of Cu in SrS: Cu grown by MBE for blue phosphors Y.B. Xina,b,*, W. Tonga, ON M9W 5AS, Canada Abstract Systematic studies of MBE grown SrS:Cu thin film blue phosphors Thin film SrS:Cu is a potential candidate for blue electro- luminescent (EL) phosphors. Although recent

  6. Biomass, Flavonol Levels and Sensory Characteristics of Allium cultivars Grown Hydroponically at Ambient and

    E-Print Network [OSTI]

    Paré, Paul W.

    04ICES-136 Biomass, Flavonol Levels and Sensory Characteristics of Allium cultivars Grown growth chambers to evaluate the effect of elevated CO2 (1200 ppm) versus ambient CO2 (400 ppm) on biomass planting (dap). Regardless of cultivar or dap, plants grown at elevated CO2 had greater biomass

  7. Identification of optimum potassium nutrition of greenhouse plants grown in recirculating subirrigation

    E-Print Network [OSTI]

    Blessington, Trisha R.

    2002-01-01T23:59:59.000Z

    of this research was to determine the optimum potassium nutrition of greenhouse plants grown in recirculating subirrigation. New Guinea impatiens 'Ovation Salmon Pink Swirl' were grown in recirculating subirrigation trays using 0 -12 mM K, with constant 1.5 mM P...

  8. Optical characterization of InN layers grown by high-pressure chemical vapor deposition

    E-Print Network [OSTI]

    Nabben, Reinhard

    and optical properties of InN films grown on sapphire and GaN/sapphire templates. Results obtained from Raman analyzed in this contribution were grown on GaN/sapphire and sapphire 0001 substrates by HPCVD, utilizing to optical absorption edge estimates obtained from optical transmission spectra analysis. The analysis shows

  9. TEM studies of laterally overgrown GaN layers grown on non-polar substrates

    E-Print Network [OSTI]

    Liliental-Weber, Z.; Ni, X.; Morkoc, H.

    2006-01-01T23:59:59.000Z

    between these substrates and the GaN layers leads to a highpendeo-epitaxial GaN layer grown on (1120) 4H-SiC substrate.in GaN layers grown on polar and non-polar substrates are

  10. Localized Si enrichment in coherent self-assembled Ge islands grown by molecular beam epitaxy on (001)Si single crystal

    SciTech Connect (OSTI)

    Valvo, M. [Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 64, I-95127 Catania (Italy); Bongiorno, C.; Giannazzo, F. [IMM-CNR, VIII strada 5, 95121 Catania (Italy); Terrasi, A. [Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 64, I-95127 Catania (Italy); MATIS IMM-CNR UOS Catania (Universita), via S. Sofia 64, 95123 Catania (Italy)

    2013-01-21T23:59:59.000Z

    Transmission electron microscopy (TEM), atomic force microscopy, and Rutherford backscattering spectrometry (RBS) have been used to investigate the morphology, structure, and composition of self-assembled Ge islands grown on Si (001) substrates by molecular beam epitaxy (MBE) at different temperatures. Increasing the temperature from 550 Degree-Sign C to 700 Degree-Sign C causes progressive size and shape uniformity, accompanied by enhanced Si-Ge intermixing within the islands and their wetting layer. Elemental maps obtained by energy filtered-TEM (EF-TEM) clearly show pronounced Si concentration not only in correspondence of island base perimeters, but also along their curved surface boundaries. This phenomenon is strengthened by an increase of the growth temperature, being practically negligible at 550 Degree-Sign C, while very remarkable already at 650 Degree-Sign C. The resulting island shape is affected, since this localized Si enrichment not only provides strain relief near their highly stressed base perimeters but it also influences the cluster surface energy by effective alloying, so as to form Si-enriched SiGe interfaces. Further increase to 700 Degree-Sign C causes a shape transition where more homogenous Si-Ge concentration profiles are observed. The crucial role played by local 'flattened' alloyed clusters, similar to truncated pyramids with larger bases and enhanced Si enrichment at coherently stressed interfaces, has been further clarified by EF-TEM analysis of a multi-layered Ge/Si structure containing stacked Ge islands grown at 650 Degree-Sign C. Sharp accumulation of Si has been here observed not only in proximity of the uncapped island surface in the topmost layer but also at the buried Ge/Si interfaces and even in the core of such capped Ge islands.

  11. Electrical characterization of electrochemically grown single copper nanowires

    E-Print Network [OSTI]

    Ludwig-Maximilians-Universität, München

    of nanometer-sized conducting wires synthesized from a wide range of materials are crucial technological as report a method for producing an ensemble of single and polycrystalline Cu nanowires in polycarbonate steps, schematically depicted in Fig. 1 a . First, polycarbonate foils Makrofol N, thickness 30 m a

  12. Wide range radioactive gas concentration detector

    DOE Patents [OSTI]

    Anderson, David F. (Los Alamos, NM)

    1984-01-01T23:59:59.000Z

    A wide range radioactive gas concentration detector and monitor which is capable of measuring radioactive gas concentrations over a range of eight orders of magnitude. The device of the present invention is designed to have an ionization chamber which is sufficiently small to give a fast response time for measuring radioactive gases but sufficiently large to provide accurate readings at low concentration levels. Closely spaced parallel plate grids provide a uniform electric field in the active region to improve the accuracy of measurements and reduce ion migration time so as to virtually eliminate errors due to ion recombination. The parallel plate grids are fabricated with a minimal surface area to reduce the effects of contamination resulting from absorption of contaminating materials on the surface of the grids. Additionally, the ionization chamber wall is spaced a sufficient distance from the active region of the ionization chamber to minimize contamination effects.

  13. Wide band stepped frequency ground penetrating radar

    DOE Patents [OSTI]

    Bashforth, M.B.; Gardner, D.; Patrick, D.; Lewallen, T.A.; Nammath, S.R.; Painter, K.D.; Vadnais, K.G.

    1996-03-12T23:59:59.000Z

    A wide band ground penetrating radar system is described embodying a method wherein a series of radio frequency signals is produced by a single radio frequency source and provided to a transmit antenna for transmission to a target and reflection therefrom to a receive antenna. A phase modulator modulates those portions of the radio frequency signals to be transmitted and the reflected modulated signal is combined in a mixer with the original radio frequency signal to produce a resultant signal which is demodulated to produce a series of direct current voltage signals, the envelope of which forms a cosine wave shaped plot which is processed by a Fast Fourier Transform Unit 44 into frequency domain data wherein the position of a preponderant frequency is indicative of distance to the target and magnitude is indicative of the signature of the target. 6 figs.

  14. Wide band stepped frequency ground penetrating radar

    DOE Patents [OSTI]

    Bashforth, Michael B. (Buellton, CA); Gardner, Duane (Santa Maria, CA); Patrick, Douglas (Santa Maria, CA); Lewallen, Tricia A. (Ventura, CA); Nammath, Sharyn R. (Santa Barbara, CA); Painter, Kelly D. (Goleta, CA); Vadnais, Kenneth G. (Alexandria, VA)

    1996-01-01T23:59:59.000Z

    A wide band ground penetrating radar system (10) embodying a method wherein a series of radio frequency signals (60) is produced by a single radio frequency source (16) and provided to a transmit antenna (26) for transmission to a target (54) and reflection therefrom to a receive antenna (28). A phase modulator (18) modulates those portion of the radio frequency signals (62) to be transmitted and the reflected modulated signal (62) is combined in a mixer (34) with the original radio frequency signal (60) to produce a resultant signal (53) which is demodulated to produce a series of direct current voltage signals (66) the envelope of which forms a cosine wave shaped plot (68) which is processed by a Fast Fourier Transform unit 44 into frequency domain data (70) wherein the position of a preponderant frequency is indicative of distance to the target (54) and magnitude is indicative of the signature of the target (54).

  15. Imaging spectrometer wide field catadioptric design

    DOE Patents [OSTI]

    Chrisp; Michael P. (Danville, CA)

    2008-08-19T23:59:59.000Z

    A wide field catadioptric imaging spectrometer with an immersive diffraction grating that compensates optical distortions. The catadioptric design has zero Petzval field curvature. The imaging spectrometer comprises an entrance slit for transmitting light, a system with a catadioptric lens and a dioptric lens for receiving the light and directing the light, an immersion grating, and a detector array. The entrance slit, the system for receiving the light, the immersion grating, and the detector array are positioned wherein the entrance slit transmits light to the system for receiving the light and the system for receiving the light directs the light to the immersion grating and the immersion grating receives the light and directs the light through the system for receiving the light to the detector array.

  16. Final Report: Laser-Material Interactions Relevant to Analytic Spectroscopy of Wide Band Gap Materials

    SciTech Connect (OSTI)

    Dickinson, J. T. [Washington State University] [Washington State University

    2014-04-05T23:59:59.000Z

    We summarize our studies aimed at developing an understanding of the underlying physics and chemistry in terms of laser materials interactions relevant to laser-based sampling and chemical analysis of wide bandgap materials. This work focused on the determination of mechanisms for the emission of electrons, ions, atoms, and molecules from laser irradiation of surfaces. We determined the important role of defects on these emissions, the thermal, chemical, and physical interactions responsible for matrix effects and mass-dependent transport/detection. This work supported development of new techniques and technology for the determination of trace elements contained such as nuclear waste materials.

  17. Accelerometer using atomic waves for space applications

    E-Print Network [OSTI]

    of Bose-Einstein condensation (BEC) of a dilute gas of trapped atoms in a single quantum state [18, 19, 20 of such devices in the field of navigation, surveying and analysis of earth structures. Matter-wave interferometry that the use of Bose-Einstein condensed atoms will bring the science of atom optics, and in particular atom

  18. Epitaxially grown sputtered LaAlO sub 3 films

    SciTech Connect (OSTI)

    Lee, A.E.; Platt, C.E.; Burch, J.F.; Simon, R.W. (TRW Space Technology Group, Redondo Beach, CA (USA)); Goral, J.P.; Al-Jassim, M.M. (Solar Energy Research Institute, Golden, CO (USA))

    1990-11-05T23:59:59.000Z

    We have grown crystalline thin films of LaAlO{sub 3} using off-axis rf sputtering from a single stoichiometric target. The films grow epitaxially on SrTiO{sub 3} and LaAlO{sub 3} (100) substrates as well as on YBa{sub 2}Cu{sub 3}O{sub 7} thin films. We report on the growth conditions used to make these films, the properties of the films, and the properties of bilayer and trilayer structures containing both LaAlO{sub 3} and YBa{sub 2}Cu{sub 3}O{sub 7} films. Transmission electron microscopy cross-sectional and x-ray diffraction analyses indicate that all the constituent films in the multilayers grow epitaxially and that the interfaces between the films are sharply defined. Preliminary transport measurements on these multilayers show that LaAlO{sub 3} can be used for dielectric layers in a variety of high-temperature superconductor electronic circuits.

  19. Atomic Cascade in Muonic and Hadronic Hydrogen Atoms

    E-Print Network [OSTI]

    T. S. Jensen; V. P. Popov; V. N. Pomerantsev

    2007-12-18T23:59:59.000Z

    The atomic cascade in $\\mu^- p$ and $\\pi^- p$ atoms has been studied with the improved version of the extended cascade model in which new quantum mechanical calculations of the differential and integral cross sections of the elastic scattering, Stark transitions and Coulomb de-excitation have been included for the principal quantum number values $n\\le 8$ and the relative energies $E \\ge 0.01$ eV. The $X$-ray yields and kinetic energy distributions are compared with the experimental data.

  20. Quantum Electrodynamics of Atomic Resonances

    E-Print Network [OSTI]

    Miguel Ballesteros; Jérémy Faupin; Jürg Fröhlich; Baptiste Schubnel

    2015-03-09T23:59:59.000Z

    A simple model of an atom interacting with the quantized electromagnetic field is studied. The atom has a finite mass $m$, finitely many excited states and an electric dipole moment, $\\vec{d}_0 = -\\lambda_{0} \\vec{d}$, where $\\| d^{i}\\| = 1,$ $ i=1,2,3,$ and $\\lambda_0$ is proportional to the elementary electric charge. The interaction of the atom with the radiation field is described with the help of the Ritz Hamiltonian, $-\\vec{d}_0\\cdot \\vec{E}$, where $\\vec{E}$ is the electric field, cut off at large frequencies. A mathematical study of the Lamb shift, the decay channels and the life times of the excited states of the atom is presented. It is rigorously proven that these quantities are analytic functions of the momentum $\\vec{p}$ of the atom and of the coupling constant $\\lambda_0$, provided $|\\vec{p}| < mc$ and $| \\Im\\vec{p} |$ and $| \\lambda_{0} |$ are sufficiently small. The proof relies on a somewhat novel inductive construction involving a sequence of `smooth Feshbach-Schur maps' applied to a complex dilatation of the original Hamiltonian, which yields an algorithm for the calculation of resonance energies that converges super-exponentially fast.

  1. As-grown deep-level defects in n-GaN grown by metal-organic chemical vapor deposition on freestanding GaN

    SciTech Connect (OSTI)

    Chen Shang; Ishikawa, Kenji; Hori, Masaru [Nagoya University, Chikusa, Nagoya 464-8603 (Japan); Honda, Unhi; Shibata, Tatsunari; Matsumura, Toshiya; Tokuda, Yutaka [Aichi Institute of Technology, Yakusa, Toyota 470-0392 (Japan); Ueda, Hiroyuki; Uesugi, Tsutomu; Kachi, Tetsu [Toyota Central R and D Laboratories, Inc., Yokomichi, Nagakute 480-1192 (Japan)

    2012-09-01T23:59:59.000Z

    Traps of energy levels E{sub c}-0.26 and E{sub c}-0.61 eV have been identified as as-grown traps in n-GaN grown by metal-organic chemical vapor deposition by using deep level transient spectroscopy of the Schottky contacts fabricated by resistive evaporation. The additional traps of E{sub c}-0.13 and E{sub c}-0.65 eV have been observed in samples whose contacts are deposited by electron-beam evaporation. An increase in concentration of the E{sub c}-0.13 and E{sub c}-0.65 eV traps when approaching the interface between the contact and the GaN film supports our argument that these traps are induced by electron-beam irradiation. Conversely, the depth profiles of as-grown traps show different profiles between several samples with increased or uniform distribution in the near surface below 50 nm. Similar profiles are observed in GaN grown on a sapphire substrate. We conclude that the growth process causes these large concentrations of as-grown traps in the near-surface region. It is speculated that the finishing step in the growth process should be an essential issue in the investigation of the surface state of GaN.

  2. Degeneracy Breaking of Hydrogen Atom

    E-Print Network [OSTI]

    Agung Trisetyarso; Pantur Silaban

    2014-11-21T23:59:59.000Z

    The three dimensional rotation group, SO(3), is a symmetry group of the normal hydrogen atom. Each reducible representation of this group can be associated with a degenerate energy level. If this atom is placed in an external magnetic field, the interaction between the orbital magnetic moment with this field will lead to a symmetry breaking where the symmetry group of the atom is a new group distinct from the SO(3) group. This phenomenon describes the normal Zeeman effect, where a degenerate energy level splits into several new energy levels. It is explicitly shown that each of the new energy levels can be associated with an irreducible representation of the new symmetry group.

  3. Atomizing, continuous, water monitoring module

    DOE Patents [OSTI]

    Thompson, Cyril V. (Knoxville, TN); Wise, Marcus B. (Kingston, TN)

    1997-01-01T23:59:59.000Z

    A system for continuously analyzing volatile constituents of a liquid is described. The system contains a pump for continuously pumping the liquid to be tested at a predetermined flow rate into an extracting container through a liquid directing tube having an orifice at one end and positioned to direct the liquid into the extracting container at a flow rate sufficient to atomize the liquid within the extracting container. A continuous supply of helium carrier gas at a predetermined flow rate is directed through a tube into the extracting container and co-mingled with the atomized liquid to extract the volatile constituents contained within the atomized liquid. The helium containing the extracted volatile constituents flows out of the extracting container into a mass spectrometer for an analysis of the volatile constituents of the liquid.

  4. Atomizing, continuous, water monitoring module

    DOE Patents [OSTI]

    Thompson, C.V.; Wise, M.B.

    1997-07-08T23:59:59.000Z

    A system for continuously analyzing volatile constituents of a liquid is described. The system contains a pump for continuously pumping the liquid to be tested at a predetermined flow rate into an extracting container through a liquid directing tube having an orifice at one end and positioned to direct the liquid into the extracting container at a flow rate sufficient to atomize the liquid within the extracting container. A continuous supply of helium carrier gas at a predetermined flow rate is directed through a tube into the extracting container and co-mingled with the atomized liquid to extract the volatile constituents contained within the atomized liquid. The helium containing the extracted volatile constituents flows out of the extracting container into a mass spectrometer for an analysis of the volatile constituents of the liquid. 3 figs.

  5. Elimination of columnar microstructure in N-face InAlN, lattice-matched to GaN, grown by plasma-assisted molecular beam epitaxy in the N-rich regime

    SciTech Connect (OSTI)

    Ahmadi, Elaheh; Wienecke, Steven; Keller, Stacia; Mishra, Umesh K. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States); Shivaraman, Ravi; Wu, Feng; Kaun, Stephen W.; Speck, James S. [Materials Department, University of California, Santa Barbara, California 93106 (United States)

    2014-02-17T23:59:59.000Z

    The microstructure of N-face InAlN layers, lattice-matched to GaN, was investigated by scanning transmission electron microscopy and atom probe tomography. These layers were grown by plasma-assisted molecular beam epitaxy (PAMBE) in the N-rich regime. Microstructural analysis shows an absence of the lateral composition modulation that was previously observed in InAlN films grown by PAMBE. A room temperature two-dimensional electron gas (2DEG) mobility of 1100 cm{sup 2}/V s and 2DEG sheet charge density of 1.9?×?10{sup 13}?cm{sup ?2} was measured for N-face GaN/AlN/GaN/InAlN high-electron-mobility transistors with lattice-matched InAlN back barriers.

  6. Fact #844: October 27, 2014 Electricity Generated from Coal has Declined while Generation from Natural Gas has Grown – Dataset

    Broader source: Energy.gov [DOE]

    Excel file with dataset for Fact #844: Electricity Generated from Coal has Declined while Generation from Natural Gas has Grown

  7. Green emission from Er-doped GaN grown by molecular beam epitaxy on Si substrates

    E-Print Network [OSTI]

    Steckl, Andrew J.

    Green emission from Er-doped GaN grown by molecular beam epitaxy on Si substrates R. Birkhahn and A grown by MBE on sapphire substrates. In this letter, we report on Er-doped GaN growth experiments on Si Er-doped -GaN thin films grown on Si 111 . The GaN was grown by molecular beam epitaxy using solid

  8. Nanoplasmonic Lattices for Ultracold atoms

    E-Print Network [OSTI]

    M. Gullans; T. Tiecke; D. E. Chang; J. Feist; J. D. Thompson; J. I. Cirac; P. Zoller; M. D. Lukin

    2014-07-25T23:59:59.000Z

    We propose to use sub-wavelength confinement of light associated with the near field of plasmonic systems to create nanoscale optical lattices for ultracold atoms. Our approach combines the unique coherence properties of isolated atoms with the sub-wavelength manipulation and strong light-matter interaction associated with nano-plasmonic systems. It allows one to considerably increase the energy scales in the realization of Hubbard models and to engineer effective long-range interactions in coherent and dissipative many-body dynamics. Realistic imperfections and potential applications are discussed.

  9. Single Molecule DNA Detection with an Atomic Vapor Notch Filter

    E-Print Network [OSTI]

    Uhland, Denis; Widmann, Matthias; Lee, Sang-Yun; Wrachtrup, Jörg; Gerhardt, Ilja

    2015-01-01T23:59:59.000Z

    The detection of single molecules has facilitated many advances in life- and material-sciences. Commonly, it founds on the fluorescence detection of single molecules, which are for example attached to the structures under study. For fluorescence microscopy and sensing the crucial parameters are the collection and detection efficiency, such that photons can be discriminated with low background from a labeled sample. Here we show a scheme for filtering the excitation light in the optical detection of single stranded labeled DNA molecules. We use the narrow-band filtering properties of a hot atomic vapor to filter the excitation light from the emitted fluorescence of a single emitter. The choice of atomic sodium allows for the use of fluorescent dyes, which are common in life-science. This scheme enables efficient photon detection, and a statistical analysis proves an enhancement of the optical signal of more than 15% in a confocal and in a wide-field configuration.

  10. Improved Energy Conversion Efficiency in Wide Bandgap Cu(In,Ga)Se2 Solar Cells

    SciTech Connect (OSTI)

    Contreras, M. A.; Mansfield, L. M.; Egaas, B.; Li, J.; Romero, M.; Noufi, R.; Rudiger-Voigt, E.; Mannstadt, W.

    2011-01-01T23:59:59.000Z

    This report outlines improvements to the energy conversion efficiency in wide bandgap (E{sub g} > ;1.2 eV) solar cells based on CuIn{sub 1-x}Ga{sub x}Se{sub 2}. Using (a) alkaline containing high temperature glass substrates, (b) elevated substrate temperatures 600 C-650 C and (c) high vacuum evaporation from elemental sources following NREL's three-stage process, we have been able to improve the performance of wider bandgap solar cells with 1.2 < E{sub g} < 1.45 eV. Initial results of this work have led to efficiencies >18% for absorber bandgaps {approx}1.30 eV and efficiencies {approx}16% for bandgaps up to {approx}1.45 eV. In comparing J-V parameters in similar materials, we establish gains in the open-circuit voltage and, to a lesser degree, the fill factor value, as the reason for the improved performance. The higher voltages seen in these wide gap materials grown at high substrate temperatures may be due to reduced recombination at the grain boundary of such absorber films. Solar cell results, absorber materials characterization, and experimental details are reported.

  11. Roles of ionic strength and biofilm roughness on adhesion kinetics of Escherichia coli onto groundwater biofilm grown on

    E-Print Network [OSTI]

    Boppart, Stephen

    groundwater biofilm grown on PVC surfaces Dao Janjaroen a , Fangqiong Ling a , Guillermo Monroy b , Nicolas Pathogens a b s t r a c t Mechanisms of Escherichia coli attachment on biofilms grown on PVC coupons were. coli on clean PVC surfaces and biofilms grown on PVC surfaces for different ages. Two mechanisms of E

  12. Strain relaxation in GaN grown on vicinal 4H-SiC(0001) J. Pernot and E. Bustarret

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Strain relaxation in GaN grown on vicinal 4H-SiC(0001) substrates J. Pernot and E. Bustarret, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands Abstract The strain of GaN layers grown by Metal Organic, the GaN layer grown on on-axis substrate has a slight and homogeneous tensile in-plane stress due

  13. Scanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Epitaxy

    E-Print Network [OSTI]

    doped MOCVD grown GaN on sapphire substrate [2]. Park et al. performed the growth of Cr doped GaN singleScanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Orleans, New Orleans, LA 70148, USA Abstract: Cr doped GaN was grown by rf N-plasma molecular beam epitaxy

  14. Alumina atomic layer deposition nanocoatings on primary diamond particles using a fluidized bed reactor

    E-Print Network [OSTI]

    George, Steven M.

    /high-temperature (HP/HT) synthesis methods [4­7] led to the discovery of polycrystalline diamond grit and the manufacture of polycrystalline diamond compact (PDC) materials [8]. PDC cutters are well known and widely usedAlumina atomic layer deposition nanocoatings on primary diamond particles using a fluidized bed

  15. Anodic Aluminum Oxide Templated Channel Electrodes via Atomic Layer A. B. F. Martinsona,b

    E-Print Network [OSTI]

    60439, USA Dye-sensitized solar cells (DSSCs) utilize high surface area metal oxide sintered particle aluminum oxide membranes via atomic layer deposition. Introduction Dye sensitized solar cells (DSSCs) These photoelectrochemical cells use molecular dyes to sensitize high area, wide band gap semiconductor oxide photoanodes

  16. BulkSMT: Designing SMT Processors for Atomic-Block Execution

    E-Print Network [OSTI]

    Zaragoza, Universidad de

    BulkSMT: Designing SMT Processors for Atomic-Block Execution Xuehai Qian, Benjamin Sahelices single-context cores as building blocks -- rather than the widely-used Simultaneous Multithreading (SMT) cores. As a result, they are underutilizing hardware resources. This paper presents the first SMT design

  17. An ultra-bright atom laser

    E-Print Network [OSTI]

    V. Bolpasi; N. K. Efremidis; M. J. Morrissey; P. Condylis; D. Sahagun; M. Baker; W. von Klitzing

    2013-11-25T23:59:59.000Z

    We present a novel, ultra-bright atom-laser and ultra-cold thermal atom beam. Using rf-radiation we strongly couple the magnetic hyperfine levels of 87Rb atoms in a magnetically trapped Bose-Einstein condensate. At low rf-frequencies gravity opens a small hole in the trapping potenital and a well collimated, extremely bright atom laser emerges from just below the condensate. As opposed to traditional atom lasers based on weak coupling, this technique allows us to outcouple atoms at an arbitrarily large rate. We demonstrate an increase in flux per atom in the BEC by a factor of sixteen compared to the brightest quasi-continuous atom laser. Furthermore, we produce by two orders of magnitude the coldest thermal atom beam to date (200 nK).

  18. Wide Area Security Region Final Report

    SciTech Connect (OSTI)

    Makarov, Yuri V.; Lu, Shuai; Guo, Xinxin; Gronquist, James; Du, Pengwei; Nguyen, Tony B.; Burns, J. W.

    2010-03-31T23:59:59.000Z

    This report develops innovative and efficient methodologies and practical procedures to determine the wide-area security region of a power system, which take into consideration all types of system constraints including thermal, voltage, voltage stability, transient and potentially oscillatory stability limits in the system. The approach expands the idea of transmission system nomograms to a multidimensional case, involving multiple system limits and parameters such as transmission path constraints, zonal generation or load, etc., considered concurrently. The security region boundary is represented using its piecewise approximation with the help of linear inequalities (so called hyperplanes) in a multi-dimensional space, consisting of system parameters that are critical for security analyses. The goal of this approximation is to find a minimum set of hyperplanes that describe the boundary with a given accuracy. Methodologies are also developed to use the security hyperplanes, pre-calculated offline, to determine system security margins in real-time system operations, to identify weak elements in the system, and to calculate key contributing factors and sensitivities to determine the best system controls in real time and to assist in developing remedial actions and transmission system enhancements offline . A prototype program that automates the simulation procedures used to build the set of security hyperplanes has also been developed. The program makes it convenient to update the set of security hyperplanes necessitated by changes in system configurations. A prototype operational tool that uses the security hyperplanes to assess security margins and to calculate optimal control directions in real time has been built to demonstrate the project success. Numerical simulations have been conducted using the full-size Western Electricity Coordinating Council (WECC) system model, and they clearly demonstrated the feasibility and the effectiveness of the developed technology. Recommendations for the future work have also been formulated.

  19. Electrical behavior of atomic layer deposited high quality SiO{sub 2} gate dielectric

    SciTech Connect (OSTI)

    Pradhan, Sangram K.; Tanyi, Ekembu K.; Skuza, Jonathan R.; Xiao, Bo; Pradhan, Aswini K., E-mail: apradhan@nsu.edu [Center for Materials Research, Norfolk State University, 700 Park Ave., Norfolk, Virginia 23504 (United States)

    2015-01-01T23:59:59.000Z

    Comprehensive and systematic electrical studies were performed on fabrication of high quality SiO{sub 2} thin films MOS capacitor using the robust, novel, and simple atomic layer deposition (ALD) technique using highly reactive ozone and tris (dimethylamino) silane (TDMAS) precursors. Ideal capacitance–voltage curve exhibits a very small frequency dispersion and hysteresis behavior of the SiO{sub 2} MOS capacitor grown at 1?s TDMAS pulse, suggesting excellent interfacial quality and purity of the film as probed using x-ray photoelectron studies. The flat-band voltage of the device shifted from negative toward positive voltage axis with increase of TDMAS pulses from 0.2 to 2 s. Based on an equivalent oxide thickness point of view, all SiO{sub 2} films have gate leakage current density of (5.18?×?10{sup ?8} A/cm{sup 2}) as well as high dielectric break down fields of more than (?10 MV/cm), which is better and comparable to that of thermally grown SiO{sub 2} at temperatures above 800?°C. These appealing electrical properties of ALD grown SiO{sub 2} thin films enable its potential applications such as high-quality gate insulators for thin film MOS transistors, as well as insulators for sensor and nanostructures on nonsilicon substrates.

  20. ELECTRONIC SPUTTERING: FROM ATOMIC PHYSICS

    E-Print Network [OSTI]

    Johnson, Robert E.

    ELECTRONIC SPUTTERING: FROM ATOMIC PHYSICS TO CONTINUUM MECHANICS Ejection of simple and complex molecules from surfaces probes the response of condensed matter to electronic excitations and has and Engineering Physics at the University of Virginia, Charlottesville. Bo Sundqvist holds the Chair in Ion

  1. Photoabsorption by Ions and Atoms

    SciTech Connect (OSTI)

    Manson, Steven T. [Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303 (United States)

    2004-12-01T23:59:59.000Z

    Recent progress in theoretical and experimental investigations of photoabsorption by atoms and ions is presented. Specifically, examples of near-chaotic behavior in photoionization of positive ions, low-energy manifestations of nondipole effects, high-energy breakdown of the single particle picture and new phenomenology uncovered in the inner-shell photoabsorption by negative ions are discussed.

  2. Stable atomic structure of NiTi austenite

    SciTech Connect (OSTI)

    Zarkevich, Nikolai A [Ames Laboratory; Johnson, Duane D [Ames Laboratory

    2014-08-01T23:59:59.000Z

    Nitinol (NiTi), the most widely used shape-memory alloy, exhibits an austenite phase that has yet to be identified. The usually assumed austenitic structure is cubic B2, which has imaginary phonon modes, hence it is unstable. We suggest a stable austenitic structure that “on average” has B2 symmetry (observed by x-ray and neutron diffraction), but it exhibits finite atomic displacements from the ideal B2 sites. The proposed structure has a phonon spectrum that agrees with that from neutron scattering, has diffraction spectra in agreement with x-ray diffraction, and has an energy relative to the ground state that agrees with calorimetry data.

  3. Realization of a superconducting atom chip

    E-Print Network [OSTI]

    Thomas Nirrengarten; Angie Qarry; Cédric Roux; Andreas Emmert; Gilles Nogues; Michel Brune; Jean-Michel Raimond; Serge Haroche

    2006-10-09T23:59:59.000Z

    We have trapped rubidium atoms in the magnetic field produced by a superconducting atom chip operated at liquid Helium temperatures. Up to $8.2\\cdot 10^5$ atoms are held in a Ioffe-Pritchard trap at a distance of 440 $\\mu$m from the chip surface, with a temperature of 40 $\\mu$K. The trap lifetime reaches 115 s at low atomic densities. These results open the way to the exploration of atom--surface interactions and coherent atomic transport in a superconducting environment, whose properties are radically different from normal metals at room temperature.

  4. Physical properties of epitaxial ZrN/MgO(001) layers grown by reactive magnetron sputtering

    SciTech Connect (OSTI)

    Mei, A. B.; Zhang, C.; Sardela, M.; Eckstein, J. N.; Rockett, A. [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 (United States)] [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 (United States); Howe, B. M. [Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, Ohio 45433-7817 (United States)] [Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, Ohio 45433-7817 (United States); Hultman, L. [Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden)] [Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden); Petrov, I.; Greene, J. E. [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 and Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden)] [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 and Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden)

    2013-11-15T23:59:59.000Z

    Single-crystal ZrN films, 830 nm thick, are grown on MgO(001) at 450 °C by magnetically unbalanced reactive magnetron sputtering. The combination of high-resolution x-ray diffraction reciprocal lattice maps, high-resolution cross-sectional transmission electron microscopy, and selected-area electron diffraction shows that ZrN grows epitaxially on MgO(001) with a cube-on-cube orientational relationship, (001){sub ZrN}?(001){sub MgO} and [100]{sub ZrN}?[100]{sub MgO}. The layers are essentially fully relaxed with a lattice parameter of 0.4575 nm, in good agreement with reported results for bulk ZrN crystals. X-ray reflectivity results reveal that the films are completely dense with smooth surfaces (roughness = 1.3 nm, consistent with atomic-force microscopy analyses). Based on temperature-dependent electronic transport measurements, epitaxial ZrN/MgO(001) layers have a room-temperature resistivity ?{sub 300K} of 12.0 ??-cm, a temperature coefficient of resistivity between 100 and 300 K of 5.6 × 10{sup ?8}?-cm K{sup ?1}, a residual resistivity ?{sub o} below 30 K of 0.78 ??-cm (corresponding to a residual resistivity ratio ?{sub 300?}/?{sub 15K} = 15), and the layers exhibit a superconducting transition temperature of 10.4 K. The relatively high residual resistivity ratio, combined with long in-plane and out-of-plane x-ray coherence lengths, ?{sub ?} = 18 nm and ?{sub ?} = 161 nm, indicates high crystalline quality with low mosaicity. The reflectance of ZrN(001), as determined by variable-angle spectroscopic ellipsometry, decreases slowly from 95% at 1 eV to 90% at 2 eV with a reflectance edge at 3.04 eV. Interband transitions dominate the dielectric response above 2 eV. The ZrN(001) nanoindentation hardness and modulus are 22.7 ± 1.7 and 450 ± 25 GPa.

  5. Remote atom entanglement in a fiber-connected three-atom system

    E-Print Network [OSTI]

    Guo Yan-Qing; Chen Jing; Song He-Shan

    2008-05-28T23:59:59.000Z

    An Ising-type atom-atom interaction is obtained in a fiber-connected three-atom system. The interaction is effective when $\\Delta\\approx \\gamma _{0}\\gg g$. The preparations of remote two-atom and three-atom entanglement governed by this interaction are discussed in specific parameters region. The overall two-atom entanglement is very small because of the existence of the third atom. However, the three-atom entanglement can reach a maximum very close to 1.

  6. as-grown ga1-xmnxas studied: Topics by E-print Network

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

    processes.11 In materials such as CNTs, ion- ization is often quenched while knock-on hollow core.13 To control the quality of as-grown CNTs and to study intentionally...

  7. Origami-inspired nanofabrication utilizing physical and magnetic properties of in situ grown carbon nanotubes

    E-Print Network [OSTI]

    In, Hyun Jin

    2010-01-01T23:59:59.000Z

    Carbon nanotubes (CNTs), in particular the vertically-aligned variety grown through a plasma enhanced chemical vapor deposition (PECVD)-based process, are highly versatile nanostructures that can be used in a variety of ...

  8. Bi-Sr-Ca-Cu-O thin films grown by flash evaporation and pulsed laser deposition

    E-Print Network [OSTI]

    Ganapathy Subramanian, Santhana

    2004-09-30T23:59:59.000Z

    -phase 2212 films were grown on a MgO substrate using the pulsed laser deposition technique from commercially available 2212 powder. The effect of annealing on the thin films was also studied....

  9. CRYSTALLOGRAPHIC PROPERTIES AND MECHANICAL BEHAVIOR OF TITANIUM HYDRIDE LAYERS GROWN ON TITANIUM IMPLANTS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    CRYSTALLOGRAPHIC PROPERTIES AND MECHANICAL BEHAVIOR OF TITANIUM HYDRIDE LAYERS GROWN ON TITANIUM, Switzerland Keywords: SLA treated titanium - bone-anchored dental implants - transmission and scanning electron microscopy - titanium hydride sub-surface layer - epitaxy Abstract Commercially pure titanium

  10. Photoluminescence linewidths in metalorganic vapor phase epitaxially grown ordered and disordered InAlGaP alloys

    SciTech Connect (OSTI)

    Schneider, R.P. Jr.; Jones, E.D.; Lott, J.A.; Bryan, R.P. (Sandia National Laboratories, Albuquerque, New Mexico 87185-5800 (United States))

    1992-12-01T23:59:59.000Z

    The dependence of the photoluminescent properties of In{sub 0.48}(Al{sub {ital y}}Ga{sub 1{minus}{ital y}}){sub 0.52}P alloys (0{le}{ital y}{le}0.5) on growth temperature and substrate misorientation off GaAs(100) has been studied. Samples were grown using low-pressure metalorganic vapor phase epitaxy. By studying the dependence of ordering behavior in InGaP as a function of substrate misorientation and growth temperature simultaneously, a very large range in low-temperature photoluminescence emission energy---135 meV---has been obtained. The photoluminescence linewidth exhibits a strong, continuous dependence on the extent of atomic ordering (the emission energy) in the alloys. The results indicate that inhomogeneity in the microstructure of the material (i.e., between ordered'' domains and the disordered'' matrix) is the dominant photoluminescence broadening mechanism. This investigation has allowed a significant optimization of the optical properties of these materials, including the narrowest low-temperature photoluminescent linewidths reported for all of the In(Al{sub {ital y}}Ga{sub 1{minus}{ital y}})P alloys exhibiting direct band gaps (4.2 meV for InGaP).

  11. Comparison with traditional calibration Wide Area Camera Calibration Using

    E-Print Network [OSTI]

    Stanford University

    Comparison with traditional calibration Wide Area Camera Calibration Using Virtual Calibration Objects Xing Chen, James Davis, Philipp Slusallek Goal Calibrate many cameras arranged to cover a wide area working volume. Building a large physical calibration object is impractical. Solution Build

  12. Benefits of Site-wide NEPA National Environmental Policy Act...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Benefits of Site-wide NEPA National Environmental Policy Act Review (1994) Benefits of Site-wide NEPA National Environmental Policy Act Review (1994) The purpose of this guidance...

  13. Epitaxial properties of Al-doped ZnO thin films grown by pulsed laser deposition on SrTiO{sub 3}(001)

    SciTech Connect (OSTI)

    Karger, M.; Schilling, M. [Technische Universitaet Braunschweig, Institut fuer Elektrische Messtechnik und Grundlagen der Elektrotechnik, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany)

    2005-02-15T23:59:59.000Z

    Undoped and Al-doped ZnO films with dopant concentrations of nominally 1% and 10% and a thickness of 100 nm have been grown on SrTiO{sub 3}(001) by pulsed laser deposition at substrate temperatures between 650 deg. C and 820 deg. C. The epitaxial conditions were examined with high pressure in-situ reflection high energy electron diffraction (RHEED) and ex-situ x-ray diffraction (XRD) measurements in different geometries. The films are highly (1120)-oriented with a lattice mismatch between the SrTiO{sub 3}[110] direction and the c-axis of about 3%. Atomic force microscopy (AFM) revealed smooth surfaces with a roughness of d{sub rms}<5 nm and different sized islands.

  14. Domain formation due to surface steps in topological insulator Bi{sub 2}Te{sub 3} thin films grown on Si (111) by molecular beam epitaxy

    SciTech Connect (OSTI)

    Borisova, S.; Kampmeier, J.; Mussler, G.; Grützmacher, D. [Peter Grünberg Institute-9, Forschungszentrum Jülich, Jülich 52425 (Germany) [Peter Grünberg Institute-9, Forschungszentrum Jülich, Jülich 52425 (Germany); Jülich Aachen Research Alliance, Fundamentals of Future Information Technologies, Jülich 52425 (Germany); Luysberg, M. [Peter Grünberg Institute-5 and Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, Jülich 52425 (Germany)] [Peter Grünberg Institute-5 and Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, Jülich 52425 (Germany)

    2013-08-19T23:59:59.000Z

    The atomic structure of topological insulators Bi{sub 2}Te{sub 3} thin films on Si (111) substrates grown in van der Waals mode by molecular beam epitaxy has been investigated by in situ scanning tunneling microscopy and scanning transmission electron microscopy. Besides single and multiple quintuple layer (QL) steps, which are typical for the step-flow mode of growth, a number of 0.4 QL steps is observed. We determine that these steps originate from single steps at the substrate surface causing domain boundaries in the Bi{sub 2}Te{sub 3} film. Due to the peculiar structure of these domain boundaries the domains are stable and penetrate throughout the entire film.

  15. Greatly improved interfacial passivation of in-situ high ? dielectric deposition on freshly grown molecule beam epitaxy Ge epitaxial layer on Ge(100)

    SciTech Connect (OSTI)

    Chu, R. L. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Liu, Y. C.; Lee, W. C.; Huang, M. L.; Kwo, J., E-mail: raynien@phys.nthu.edu.tw, E-mail: mhong@phys.ntu.edu.tw [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lin, T. D.; Hong, M., E-mail: raynien@phys.nthu.edu.tw, E-mail: mhong@phys.ntu.edu.tw [Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Pi, T. W. [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China)

    2014-05-19T23:59:59.000Z

    A high-quality high-?/Ge interface has been achieved by combining molecule beam epitaxy grown Ge epitaxial layer and in-situ deposited high ? dielectric. The employment of Ge epitaxial layer has sucessfully buried and/or removed the residue of unfavorable carbon and native oxides on the chemically cleaned and ultra-high vacuum annealed Ge(100) wafer surface, as studied using angle-resolved x-ray photoelectron spectroscopy. Moreover, the scanning tunneling microscopy analyses showed the significant improvements in Ge surface roughness from 3.5?Å to 1?Å with the epi-layer growth. Thus, chemically cleaner, atomically more ordered, and morphologically smoother Ge surfaces were obtained for the subsquent deposition of high ? dielectrics, comparing with those substrates without Ge epi-layer. The capacitance-voltage (C-V) characteristics and low extracted interfacial trap density (D{sub it}) reveal the improved high-?/Ge interface using the Ge epi-layer approach.

  16. Effects of the lateral ordering of self-assembled SiGe nanoislands grown on strained Si{sub 1-x}Ge{sub x} buffer layers

    SciTech Connect (OSTI)

    Strelchuk, V. V.; Nikolenko, A. S., E-mail: nikolenko_mail@ukr.net; Lytvyn, P. M.; Kladko, V. P.; Gudymenko, A. I.; Valakh, M. Ya. [National Academy of Sciences of Ukraine, V. Lashkaryov Institute of Semiconductor Physics (Ukraine); Krasilnik, Z. F.; Lobanov, D. N.; Novikov, A. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

    2012-05-15T23:59:59.000Z

    Atomic-force microscopy, micro-Raman spectroscopy, and high resolution X-ray diffraction are applied to study the spatial ordering in single layers of SiGe nanoislands grown on a strained Si{sub 1-x}Ge{sub x} buffer sublayer. It is shown that, apart from stimulating the spatial ordering of nanoislands, the introduction of a Si{sub 1-x}Ge{sub x} sublayer leads to an enhanced role for interdiffusion processes. An unusually high increase in the volume of nanoislands in the process of the epitaxy is related to the anomalously strong diffusion from the buffer sublayer into the islands that is induced by nonuniform fields of elastic strains. The anisotropy of the islands shape and spatial ordering is discussed in terms of the anisotropy of the diffusion processes in spatially nonuniform fields of elastic strains.

  17. Mutagenic potential of plants grown on a soil amended with mutagenic municipal sewage sludge

    E-Print Network [OSTI]

    Fiedler, Daniel Alain

    1988-01-01T23:59:59.000Z

    MUTAGENIC POTENTIAL OF PLANTS GROWN ON A SOIL AMENDED WITH MUTAGENIC MUNICIPAL SEWAGE SLUDGE A Thesis by DANIEL ALAIN FIEDLER Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE May 1988 Major Subject: Agronomy MUTAGENIC POTENTIAL OF PLANTS GROWN ON A SOIL AMENDED WITH MUTAGENIC MUNICIPAL SEWAGE SLUDGE A Thesis by DANIEL ALAIN FIEDLER Approved as to sty1e and content by; Kirk W. Brown (Chairman...

  18. Optimum fertilization rate for intermediate leaf cucumber grown for once-over mechanical harvest

    E-Print Network [OSTI]

    Konderla, Timothy Michael

    1992-01-01T23:59:59.000Z

    OPTIMUM FERTILIZATION RATE FOR INTERMEDIATE LEAF CUCUMBER GROWN FOR ONCE-OVER MECHANICAL HARVEST A Thesis by TIMOTHY MICHAEL KONDERLA 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 1992 Major Subject: Horticulture OPTIMUM FERTILIZATION RATE FOR INTERMEDIATE LEAF CUCUMBER GROWN FOR ONCE-OVER MECHANICAL HARVEST A Thesis by TIMOTHY MICHAEL KONDERLA Approved as to style...

  19. Growth and fruiting responses of diverse genotypes of American Upland cotton grown in different environments 

    E-Print Network [OSTI]

    Gannaway, J. R

    1971-01-01T23:59:59.000Z

    GROWTH AND FRUITING RESPONSES OF DIVERSE GENOTYPES OF AMERICAN UPLAND COTTON GROWN IN DIFFERENT ENVIRONMENTS A Thesis JOHN ROBERT GANNAWAY Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1971 Major Subject: Plant Breeding GROWTH AND FRUITING RESPONSES OF DIVERSE GENOTYPES OF AMERICAN UPLAND COTTON GROWN IN DIFFERENT ENVIRONMENTS A Thesis by JOHN ROBERT GANNAWAY Approved as to style and content by...

  20. Surface reconstructions of cubic gallium nitride ,,001... grown by radio frequency nitrogen plasma molecular beam epitaxy

    E-Print Network [OSTI]

    observed on c-GaN 001 , depending on the growth condi- tions and the substrate. For growth of c-GaN on Ga-rich-grown GaN 001 on MgO 001 substrate. We have deduced that these variant reconstructions are com- posed of Ga; published online 27 October 2006 Cubic GaN has been grown under gallium Ga -rich growth conditions using

  1. Growth and fruiting responses of diverse genotypes of American Upland cotton grown in different environments

    E-Print Network [OSTI]

    Gannaway, J. R

    1971-01-01T23:59:59.000Z

    GROWTH AND FRUITING RESPONSES OF DIVERSE GENOTYPES OF AMERICAN UPLAND COTTON GROWN IN DIFFERENT ENVIRONMENTS A Thesis JOHN ROBERT GANNAWAY Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1971 Major Subject: Plant Breeding GROWTH AND FRUITING RESPONSES OF DIVERSE GENOTYPES OF AMERICAN UPLAND COTTON GROWN IN DIFFERENT ENVIRONMENTS A Thesis by JOHN ROBERT GANNAWAY Approved as to style and content by...

  2. Atomic Scale Design and Three-Dimensional Simulation of Ionic Diffusive Nanofluidic Channels

    E-Print Network [OSTI]

    Park, Jin Kyoung; We, Guo-Wei

    2015-01-01T23:59:59.000Z

    Recent advance in nanotechnology has led to rapid advances in nanofluidics, which has been established as a reliable means for a wide variety of applications, including molecular separation, detection, crystallization and biosynthesis. Although atomic and molecular level consideration is a key ingredient in experimental design and fabrication of nanfluidic systems, atomic and molecular modeling of nanofluidics is rare and most simulations at nanoscale are restricted to one- or two-dimensions in the literature, to our best knowledge. The present work introduces atomic scale design and three-dimensional (3D) simulation of ionic diffusive nanofluidic systems. We propose a variational multiscale framework to represent the nanochannel in discrete atomic and/or molecular detail while describe the ionic solution by continuum. Apart from the major electrostatic and entropic effects, the non-electrostatic interactions between the channel and solution, and among solvent molecules are accounted in our modeling. We deriv...

  3. World Wide Web Internet and Web Information Systems

    E-Print Network [OSTI]

    Cao, Longbing

    1 23 World Wide Web Internet and Web Information Systems ISSN 1386-145X World Wide Web DOI 10's request, provided it is not made publicly available until 12 months after publication. #12;World Wide Web worlds. Its detection is a typical use case of the broad-based Wisdom Web of Things (W2T) methodology

  4. Role of atomic collisions in fusion

    SciTech Connect (OSTI)

    Post, D.E.

    1982-04-01T23:59:59.000Z

    Atomic physics issues have played a large role in controlled fusion research. A general discussion of the present role of atomic processes in both magnetic and inertial controlled fusion work is presented.

  5. Preliminary steps to the Atomic Energy Commission

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

    program to the newly created Atomic Energy Commission. He had succeeded in ending the war, but the transition to peacetime use of atomic energy was not something the Army was...

  6. atomic kitteni lauljatar: Topics by E-print Network

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

    with atomic and molecular matter waves is a rich branch of atomic physics and quantum optics. It started with atom diffraction from crystal surfaces and the separated oscillatory...

  7. atoms barrasiye barhamkoneshhaye: Topics by E-print Network

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

    with atomic and molecular matter waves is a rich branch of atomic physics and quantum optics. It started with atom diffraction from crystal surfaces and the separated oscillatory...

  8. atomic mass spectrometry: Topics by E-print Network

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

    Negative *) Atomic composition Graham, Nick 3 Prospects in Analytical Atomic Spectrometry CERN Preprints Summary: Tendencies in five main branches of atomic spectrometry...

  9. Institute for Atom-Efficient Chemical Transformations Energy...

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

    adsorbed in a zirconium oxide nanobowl. The brown atoms are surface oxygen and the coral atoms are zirconium. Carbon, oxygen, and hydrogen atoms of fructose molecules are...

  10. Towards a high-precision atomic gyroscope

    E-Print Network [OSTI]

    Van Camp, Mackenzie A. (Mackenzie Anne)

    2013-01-01T23:59:59.000Z

    In this thesis, I report on the design and construction of the Rubidium Atomic Gyroscope Experiment (RAGE) at Draper Lab.

  11. Atomic Ordering Enhanced Electrocatalytic Activity of Nanoalloys...

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

    Ordering Enhanced Electrocatalytic Activity of Nanoalloys for Oxygen Reduction Reaction. Atomic Ordering Enhanced Electrocatalytic Activity of Nanoalloys for Oxygen Reduction...

  12. Chaotic Behaviour of Atomic Energy Levels

    E-Print Network [OSTI]

    A. Yilmaz; G. Hacibekiroglu; E. Bolcal; Y. Polatoglu

    2008-04-01T23:59:59.000Z

    The authors of this paper studied Schrodinger wave equation to investiagate the chaotic behavior of atomic energy levels in relation with three quantum numbers n, l, m by means of derived inequality. It could give rise to the siplitting of atomic spectral lines. Keywords: Chaos, Schrodinger wave equation, atomic energy levels

  13. Riso Report No. Danish Atomic Energy Commission

    E-Print Network [OSTI]

    Jagiellonski Institute of Physics Krakow, Poland and P. A. Lindgård Mogensen The Danish Atomic EnergyfM O o 8- OL '·O c/i Riso Report No. Danish Atomic Energy Commission Research Establishment Riso/t on exchangefrom: Library, Danish Atomic Energy Commission, Risd, Roskilde, Denmark #12;May, 1966 Ris6 Report No

  14. Low temperature thin film transistors with hollow cathode plasma-assisted atomic layer deposition based GaN channels

    SciTech Connect (OSTI)

    Bolat, S., E-mail: bolat@ee.bilkent.edu.tr, E-mail: aokyay@ee.bilkent.edu.tr; Tekcan, B. [Department of Electrical and Electronics Engineering, Bilkent University, Ankara 06800 (Turkey); UNAM, National Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Ozgit-Akgun, C.; Biyikli, N. [UNAM, National Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey); Okyay, A. K., E-mail: bolat@ee.bilkent.edu.tr, E-mail: aokyay@ee.bilkent.edu.tr [Department of Electrical and Electronics Engineering, Bilkent University, Ankara 06800 (Turkey); UNAM, National Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey)

    2014-06-16T23:59:59.000Z

    We report GaN thin film transistors (TFT) with a thermal budget below 250?°C. GaN thin films are grown at 200?°C by hollow cathode plasma-assisted atomic layer deposition (HCPA-ALD). HCPA-ALD-based GaN thin films are found to have a polycrystalline wurtzite structure with an average crystallite size of 9.3?nm. TFTs with bottom gate configuration are fabricated with HCPA-ALD grown GaN channel layers. Fabricated TFTs exhibit n-type field effect characteristics. N-channel GaN TFTs demonstrated on-to-off ratios (I{sub ON}/I{sub OFF}) of 10{sup 3} and sub-threshold swing of 3.3?V/decade. The entire TFT device fabrication process temperature is below 250?°C, which is the lowest process temperature reported for GaN based transistors, so far.

  15. The Future of Atomic Energy

    DOE R&D Accomplishments [OSTI]

    Fermi, E.

    1946-05-27T23:59:59.000Z

    There is definitely a technical possibility that atomic power may gradually develop into one of the principal sources of useful power. If this expectation will prove correct, great advantages can be expected to come from the fact that the weight of the fuel is almost negligible. This feature may be particularly valuable for making power available to regions of difficult access and far from deposits of coal. It also may prove a great asset in mobile power units for example in a power plant for ship propulsion. On the negative side there are some technical limitations to be applicability of atomic power of which perhaps the most serious is the impossibility of constructing light power units; also there will be some peculiar difficulties in operating atomic plants, as for example the necessity of handling highly radioactive substances which will necessitate, at least for some considerable period, the use of specially skilled personnel for the operation. But the chief obstacle in the way of developing atomic power will be the difficulty of organizing a large scale industrial development in an internationally safe way. This presents actually problems much more difficult to solve than any of the technical developments that are necessary, It will require an unusual amount of statesmanship to balance properly the necessity of allaying the international suspicion that arises from withholding technical secrets against the obvious danger of dumping the details of the procedures for an extremely dangerous new method of warfare on a world that may not yet be prepared to renounce war. Furthermore, the proper balance should be found in the relatively short time that will elapse before the 'secrets' will naturally become open knowledge by rediscovery on part of the scientists and engineers of other countries.

  16. Gauge invariant hydrogen atom Hamiltonian

    E-Print Network [OSTI]

    Wei-Min Sun; Xiang-Song Chen; Xiao-Fu Lu; Fan Wang

    2010-06-22T23:59:59.000Z

    For quantum mechanics of a charged particle in a classical external electromagnetic field, there is an apparent puzzle that the matrix element of the canonical momentum and Hamiltonian operators is gauge dependent. A resolution to this puzzle is recently provided by us in [2]. Based on the separation of the electromagnetic potential into pure gauge and gauge invariant parts, we have proposed a new set of momentum and Hamiltonian operators which satisfy both the requirement of gauge invariance and the relevant commutation relations. In this paper we report a check for the case of the hydrogen atom problem: Starting from the Hamiltonian of the coupled electron, proton and electromagnetic field, under the infinite proton mass approximation, we derive the gauge invariant hydrogen atom Hamiltonian and verify explicitly that this Hamiltonian is different from the Dirac Hamiltonian, which is the time translation generator of the system. The gauge invariant Hamiltonian is the energy operator, whose eigenvalue is the energy of the hydrogen atom. It is generally time-dependent. In this case, one can solve the energy eigenvalue equation at any specific instant of time. It is shown that the energy eigenvalues are gauge independent, and by suitably choosing the phase factor of the time-dependent eigenfunction, one can ensure that the time-dependent eigenfunction satisfies the Dirac equation.

  17. NAAP Hydrogen Atom 1/9 The Hydrogen Atom Student Guide

    E-Print Network [OSTI]

    Farritor, Shane

    Name: NAAP ­ Hydrogen Atom 1/9 The Hydrogen Atom ­ Student Guide Background Material Carefully read and the Quantum model represent the Hydrogen atom. In some cases they both describe things in the same way frequency, smaller energy, and the same velocity through space as a blue photon". #12;NAAP ­Hydrogen Atom 2

  18. Fast transport, atom sample splitting and single-atom qubit supply in two-dimensional arrays

    E-Print Network [OSTI]

    Birkl, Gerhard

    Fast transport, atom sample splitting and single-atom qubit supply in two-dimensional arrays architecture for neutral atom quantum information processing, quantum simulation and the manipulation of ultra-cold implemented functions. We introduce piezo-actuator-based transport of atom ensembles over distances of more

  19. ELECTRON COLLISIONS WITH ATOMS AND ATOMIC D.R. Schultz

    E-Print Network [OSTI]

    be found on the World Wide Web (at URL http://astro.u­strasbg.fr/OP.html). Work is underway to provide Web­based access to the Iron Project data (TIPbase, see URL http://www.am.qub.ac.uk/projects/iron/). This Web site

  20. Ultracold Atoms: How Quantum Field Theory Invaded Atomic Physics

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgram |Frank CasellaEnergyUltracold Atoms: How Quantum

  1. Engineering Atomic Quantum Reservoirs for Photons

    E-Print Network [OSTI]

    Susanne Pielawa; Luiz Davidovich; David Vitali; Giovanna Morigi

    2010-04-06T23:59:59.000Z

    We present protocols for creating entangled states of two modes of the electromagnetic field, by using a beam of atoms crossing microwave resonators. The atoms are driven by a transverse, classical field and pump correlated photons into (i) two modes of a cavity and (ii) the modes of two distant cavities. The protocols are based on a stochastic dynamics, characterized by random arrival times of the atoms and by random interaction times between atoms and cavity modes. The resulting effective model yields a master equation, whose steady state is an entangled state of the cavity modes. In this respect, the atoms act like a quantum reservoir, pulling the cavity modes into an entangled, Einstein-Podolski-Rosen (EPR) state, whose degree of entanglement is controlled by the intensity and the frequency of the transverse field. This scheme is robust against stochastic fluctuations in the atomic beam, and it does not require atomic detection nor velocity selection.

  2. Engineering Atomic Quantum Reservoirs for Photons

    E-Print Network [OSTI]

    Pielawa, Susanne; Vitali, David; Morigi, Giovanna

    2010-01-01T23:59:59.000Z

    We present protocols for creating entangled states of two modes of the electromagnetic field, by using a beam of atoms crossing microwave resonators. The atoms are driven by a transverse, classical field and pump correlated photons into (i) two modes of a cavity and (ii) the modes of two distant cavities. The protocols are based on a stochastic dynamics, characterized by random arrival times of the atoms and by random interaction times between atoms and cavity modes. The resulting effective model yields a master equation, whose steady state is an entangled state of the cavity modes. In this respect, the atoms act like a quantum reservoir, pulling the cavity modes into an entangled, Einstein-Podolski-Rosen (EPR) state, whose degree of entanglement is controlled by the intensity and the frequency of the transverse field. This scheme is robust against stochastic fluctuations in the atomic beam, and it does not require atomic detection nor velocity selection.

  3. atomic recoil laser: Topics by E-print Network

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

    Atomic Recoil Laser Quantum Physics (arXiv) Summary: We formulate a wave atom optics theory of the Collective Atomic Recoil Laser, where the atomic center-of-mass motion...

  4. Atomic Structure Calculations from the Los Alamos Atomic Physics Codes

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

    Cowan, R. D.

    The well known Hartree-Fock method of R.D. Cowan, developed at Los Alamos National Laboratory, is used for the atomic structure calculations. Electron impact excitation cross sections are calculated using either the distorted wave approximation (DWA) or the first order many body theory (FOMBT). Electron impact ionization cross sections can be calculated using the scaled hydrogenic method developed by Sampson and co-workers, the binary encounter method or the distorted wave method. Photoionization cross sections and, where appropriate, autoionizations are also calculated. Original manuals for the atomic structure code, the collisional excitation code, and the ionization code, are available from this website. Using the specialized interface, you will be able to define the ionization stage of an element and pick the initial and final configurations. You will be led through a series of web pages ending with a display of results in the form of cross sections, collision strengths or rates coefficients. Results are available in tabular and graphic form.

  5. Low gap amorphous GaN{sub 1-x}As{sub x} alloys grown on glass substrate

    SciTech Connect (OSTI)

    Yu, K. M.; Liliental-Weber, Z.; Kao, V. M.; Walukiewicz, W. [Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720-8197 (United States); Novikov, S. V.; Foxon, C. T. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Broesler, R.; Levander, A. X.; Dubon, O. D.; Wu, J. [Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720-8197 (United States); Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States)

    2010-09-06T23:59:59.000Z

    Amorphous GaN{sub 1-x}As{sub x} layers with As content in the range of x=0.1 to 0.6 were grown by molecular beam epitaxy on Pyrex glass substrate. These alloys exhibit a wide range of band gap values from 2.2 to 1.3 eV. We found that the density of the amorphous films is {approx}0.8-0.85 of their corresponding crystalline value. These amorphous films have smooth morphology, homogeneous composition, and sharp well defined optical absorption edges. The measured band gap values for the crystalline and amorphous GaN{sub 1-x}As{sub x} alloys are in excellent agreement with the predictions of the band anticrossing model. The high absorption coefficient of {approx}10{sup 5} cm{sup -1} for the amorphous GaN{sub 1-x}As{sub x} films suggests that relatively thin films (on the order of 1 {mu}m) are necessary for photovoltaic application.

  6. DOE Announces Webinars on Zero Energy Ready Homes, Wide Bandgap...

    Broader source: Energy.gov (indexed) [DOE]

    on Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications Webinar Sponsor: Fuel Cell Technologies Office The Energy...

  7. Portsmouth Proposed Plan for the Site-wide Waste Disposition...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Proposed Plan for the Site-wide Waste Disposition Evaluation Project DOE has evaluated alternatives for managing waste that would be created by decomtamination and...

  8. USFS West Wide Programmatic Environmental Impact Statement Record...

    Open Energy Info (EERE)

    Programmatic Environmental Impact Statement Record of Decision Jump to: navigation, search OpenEI Reference LibraryAdd to library Legal Document- OtherOther: USFS West Wide...

  9. Y-12 Final Site-Wide Environmental Impact Statement Approved...

    National Nuclear Security Administration (NNSA)

    Final Site-Wide Environmental Impact Statement Approved | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the Stockpile...

  10. Draft Site-Wide Environmental Impact Statement Nevada References...

    National Nuclear Security Administration (NNSA)

    Blog Home About Us Our Operations NNSA Office of General Counsel National Environmental Policy Act (NEPA) NEPA Reading Room Draft Site-Wide Environmental Impact...

  11. DOE Issues Final Site-Wide Environmental Impact Statement for...

    Broader source: Energy.gov (indexed) [DOE]

    Security Site The U.S. Department of Energy, National Nuclear Security Administration (NNSA) has issued the Final Site-Wide Environmental Impact Statement (EIS) for the Nevada...

  12. Title Page for the Site-Wide Environmental Assessment

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1440 FINAL Site-Wide Environmental Assessment of the National Renewable Energy Laboratory's South Table Mountain Complex July 2003 U.S. DEPARTMENT OF ENERGY GOLDEN FIELD OFFICE...

  13. Cover Page for the Final Site-Wide Environmental Assessment

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1440 FINAL Site-Wide Environmental Assessment of the National Renewable Energy Laboratory's South Table Mountain Complex July 2003 U.S. DEPARTMENT OF ENERGY GOLDEN FIELD OFFICE...

  14. General Atomics | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are8COaBulkTransmissionSitingProcess.pdf Jump1946865°,Park, Texas:Webinars/Puesta en Marcha,Geary,GenSelfandAtomics

  15. Cobalt intercalation at the graphene/iridium(111) interface: Influence of rotational domains, wrinkles, and atomic steps

    SciTech Connect (OSTI)

    Vlaic, S.; Kimouche, A.; Coraux, J.; Rougemaille, N. [CNRS, Inst NEEL, F-38042 Grenoble (France) [CNRS, Inst NEEL, F-38042 Grenoble (France); Univ. Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); Santos, B.; Locatelli, A. [Elettra-Sincrotrone Trieste S.C.p.A., S.S: 14 km 163.5 in AREA Science Park, I-34149 Basovizza, Trieste (Italy)] [Elettra-Sincrotrone Trieste S.C.p.A., S.S: 14 km 163.5 in AREA Science Park, I-34149 Basovizza, Trieste (Italy)

    2014-03-10T23:59:59.000Z

    Using low-energy electron microscopy, we study Co intercalation under graphene grown on Ir(111). Depending on the rotational domain of graphene on which it is deposited, Co is found intercalated at different locations. While intercalated Co is observed preferentially at the substrate step edges below certain rotational domains, it is mostly found close to wrinkles below other domains. These results indicate that curved regions (near substrate atomic steps and wrinkles) of the graphene sheet facilitate Co intercalation and suggest that the strength of the graphene/Ir interaction determines which pathway is energetically more favorable.

  16. High-electron-mobility GaN grown on free-standing GaN templates by ammonia-based molecular beam epitaxy

    SciTech Connect (OSTI)

    Kyle, Erin C. H., E-mail: erinkyle@umail.ucsb.edu; Kaun, Stephen W.; Burke, Peter G.; Wu, Feng; Speck, James S. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Wu, Yuh-Renn [Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, Taipei City 10617, Taiwan (China)

    2014-05-21T23:59:59.000Z

    The dependence of electron mobility on growth conditions and threading dislocation density (TDD) was studied for n{sup ?}-GaN layers grown by ammonia-based molecular beam epitaxy. Electron mobility was found to strongly depend on TDD, growth temperature, and Si-doping concentration. Temperature-dependent Hall data were fit to established transport and charge-balance equations. Dislocation scattering was analyzed over a wide range of TDDs (?2?×?10{sup 6}?cm{sup ?2} to ?2?×?10{sup 10}?cm{sup ?2}) on GaN films grown under similar conditions. A correlation between TDD and fitted acceptor states was observed, corresponding to an acceptor state for almost every c lattice translation along each threading dislocation. Optimized GaN growth on free-standing GaN templates with a low TDD (?2?×?10{sup 6}?cm{sup ?2}) resulted in electron mobilities of 1265 cm{sup 2}/Vs at 296?K and 3327 cm{sup 2}/Vs at 113?K.

  17. Atoms can be divided into three categories: polar, non-polar and hydrogen atom

    E-Print Network [OSTI]

    Pei-Lin You

    2010-10-10T23:59:59.000Z

    Since the time of Rutherford 1911) physicists and chemists commonly believed that with no electric field, the nucleus of an atom is at the centre of the electron cloud, atoms do not have permanent electric dipole moment (EDM), so that there is no polar atom in nature. In the fact, the idea is untested hypothesis. After ten years of intense research, our experiments showed that atoms can be divided into three categories: polar, non-polar and hydrogen atom. Alkali atoms are all polar atoms. The EDM of a Sodium, Potassium, Rubidium and Cesium atom in the ground state have been obtained as follows: d(Na)=1.28*10 to-8 power e.cm; d(K)=1.58*10 to-8 power e.cm; d(Rb)=1.70 *10 to-8 power e.cm; d(Cs)=1.86*10 to-8 power e.cm. All kind of atoms are non-polar atoms except for alkali and hydrogen atoms. Hydrogen atom is quite distinct from the others. The ground state in hydrogen is non-polar atom(d=0) but the excited state is polar atom, for example, the first excited state has a large EDM: d(H)=3ea=1.59*10 to-8 power e.cm (a is Bohr radius).

  18. Origin of color centers in the flux-grown europium gallium garnet

    SciTech Connect (OSTI)

    Aleksandrovsky, A. S.; Arkhipkin, V. G.; Bezmaternykh, L. N.; Gudim, I. A.; Krylov, A. S. [L. V. Kirensky Institute of Physics, Akademgorodok, Krasnoyarsk 660036, Russia and Siberian Federal University, Krasnoyarsk 660079 (Russian Federation); Vagizov, F. [Department of Physics, Texas A and M University, College Station, Texas 77840 (United States)

    2008-04-15T23:59:59.000Z

    Europium gallium garnet (EuGG) single crystals were grown from fluxes with various contents. Optical absorption spectra of EuGG grown from a flux containing calcium show an additional band in the ultraviolet and blue regions of the spectra as compared to the case of a calcium-free flux. Moessbauer spectra of the samples grown from the fluxes with different additives show no signs of other valence states of the europium ions except for 3+. However, they indicate changes in the crystal field due to the entrance of additive ions. The nature of the additional absorption must be the same as that for calcium-doped gadolinium gallium garnet, i.e., anion vacancies. Moessbauer isotope shifts and quadrupole splitting for EuGG are determined.

  19. Sensing mode atomic force microscope

    DOE Patents [OSTI]

    Hough, Paul V. C.; Wang, Chengpu

    2006-08-22T23:59:59.000Z

    An atomic force microscope is described having a cantilever comprising a base and a probe tip on an end opposite the base; a cantilever drive device connected to the base; a magnetic material coupled to the probe tip, such that when an incrementally increasing magnetic field is applied to the magnetic material an incrementally increasing force will be applied to the probe tip; a moveable specimen base; and a controller constructed to obtain a profile height of a specimen at a point based upon a contact between the probe tip and a specimen, and measure an adhesion force between the probe tip and the specimen by, under control of a program, incrementally increasing an amount of a magnetic field until a release force, sufficient to break the contact, is applied. An imaging method for atomic force microscopy involving measuring a specimen profile height and adhesion force at multiple points within an area and concurrently displaying the profile and adhesion force for each of the points is also described. A microscope controller is also described and is constructed to, for a group of points, calculate a specimen height at a point based upon a cantilever deflection, a cantilever base position and a specimen piezo position; calculate an adhesion force between a probe tip and a specimen at the point by causing an incrementally increasing force to be applied to the probe tip until the probe tip separates from a specimen; and move the probe tip to a new point in the group.

  20. Sensing mode atomic force microscope

    DOE Patents [OSTI]

    Hough, Paul V.; Wang, Chengpu

    2004-11-16T23:59:59.000Z

    An atomic force microscope is described having a cantilever comprising a base and a probe tip on an end opposite the base; a cantilever drive device connected to the base; a magnetic material coupled to the probe tip, such that when an incrementally increasing magnetic field is applied to the magnetic material an incrementally increasing force will be applied to the probe tip; a moveable specimen base; and a controller constructed to obtain a profile height of a specimen at a point based upon a contact between the probe tip and a specimen, and measure an adhesion force between the probe tip and the specimen by, under control of a program, incrementally increasing an amount of a magnetic field until a release force, sufficient to break the contact, is applied. An imaging method for atomic force microscopy involving measuring a specimen profile height and adhesion force at multiple points within an area and concurrently displaying the profile and adhesion force for each of the points is also described. A microscope controller is also described and is constructed to, for a group of points, calculate a specimen height at a point based upon a cantilever deflection, a cantilever base position and a specimen piezo position; calculate an adhesion force between a probe tip and a specimen at the point by causing an incrementally increasing force to be applied to the probe tip until the probe tip separates from a specimen; and move the probe tip to a new point in the group.

  1. Sensing mode atomic force microscope

    DOE Patents [OSTI]

    Hough, Paul V. C. (Port Jefferson, NY); Wang, Chengpu (Upton, NY)

    2003-01-01T23:59:59.000Z

    An atomic force microscope utilizes a pulse release system and improved method of operation to minimize contact forces between a probe tip affixed to a flexible cantilever and a specimen being measured. The pulse release system includes a magnetic particle affixed proximate the probe tip and an electromagnetic coil. When energized, the electromagnetic coil generates a magnetic field which applies a driving force on the magnetic particle sufficient to overcome adhesive forces exhibited between the probe tip and specimen. The atomic force microscope includes two independently displaceable piezo elements operable along a Z-axis. A controller drives the first Z-axis piezo element to provide a controlled approach between the probe tip and specimen up to a point of contact between the probe tip and specimen. The controller then drives the first Z-axis piezo element to withdraw the cantilever from the specimen. The controller also activates the pulse release system which drives the probe tip away from the specimen during withdrawal. Following withdrawal, the controller adjusts the height of the second Z-axis piezo element to maintain a substantially constant approach distance between successive samples.

  2. Hydrogen Atom in Relativistic Motion

    E-Print Network [OSTI]

    M. Jarvinen

    2005-04-11T23:59:59.000Z

    The Lorentz contraction of bound states in field theory is often appealed to in qualitative descriptions of high energy particle collisions. Surprisingly, the contraction has not been demonstrated explicitly even in simple cases such as the hydrogen atom. It requires a calculation of wave functions evaluated at equal (ordinary) time for bound states in motion. Such wave functions are not obtained by kinematic boosts from the rest frame. Starting from the exact Bethe-Salpeter equation we derive the equal-time wave function of a fermion-antifermion bound state in QED, i.e., positronium or the hydrogen atom, in any frame to leading order in alpha. We show explicitly that the bound state energy transforms as the fourth component of a vector and that the wave function of the fermion-antifermion Fock state contracts as expected. Transverse photon exchange contributes at leading order to the binding energy of the bound state in motion. We study the general features of the corresponding fermion-antifermion-photon Fock states, and show that they do not transform by simply contracting. We verify that the wave function reduces to the light-front one in the infinite momentum frame.

  3. Responses of Some Dwarf Bean (Phaseolus vulgaris L.) Genotypes Grown in Turkey to Zinc and Boron Applications

    E-Print Network [OSTI]

    Hamurcu, Mehmet; Hakki, Erdogan E; Babaoglu, Mehmet; Gezgin, Sait

    2009-01-01T23:59:59.000Z

    local populations of dwarf bean genotypes, grown extensivelyand Discussion Responses of dwarf bean genotypes used in thebiomass (g plant -1 ) of dwarf bean genotypes When responses

  4. Evaluation of GaN substrates grown in supercritical basic ammonia

    SciTech Connect (OSTI)

    Saito, Makoto; Yamada, Hisashi; Iso, Kenji; Sato, Hitoshi; Hirasawa, Hirohiko; Kamber, Derrick S.; Hashimoto, Tadao; Baars, Steven P. den; Speck, James S.; Nakamura, Shuji [Materials Department, University of California, Santa Barbara, California 93106 (United States)

    2009-02-02T23:59:59.000Z

    GaN crystals grown by the basic ammonothermal method were investigated for their use as substrates for device regrowth. X-ray diffraction analysis indicated that the substrates contained multiple grains while secondary ion mass spectroscopy (SIMS) revealed a high concentration of hydrogen, oxygen, and sodium. Despite these drawbacks, the emission from the light emitting diode structures grown by metal organic chemical vapor deposition on both the c-plane and m-plane epitaxial wafers was demonstrated. The SIMS depth profiles showed that the diffusion of the alkali metal from the substrate into the epitaxial film was small, especially in the m-direction.

  5. Extraction of absorption coefficients from GaN nanowires grown on opaque substrates

    E-Print Network [OSTI]

    Jayaprakash, Rahul; Germanis, Savvas; Androulidaki, Maria; Tsagaraki, Katerina; Georgakilas, Alexandros; Pelekanos, Nikos T

    2014-01-01T23:59:59.000Z

    We demonstrate a new method to measure absorption coefficients in any family of nanowires, provided they are grown on a substrate having considerable difference in permittivity with the nanowire-air matrix. In the case of high crystal quality, strain-free GaN nanowires, grown on Si (111) substrates with a density of ~1010 cm-2, the extracted absorption coefficients do not exhibit any enhancement compared to bulk GaN values, unlike relevant claims in the literature. This may be attributed to the relatively small diameters, short heights, and high densities of our nanowire arrays.

  6. Submilliampere threshold current pseudomorphic InGaAs/AlGaAs buried-heterostructure quantum well lasers grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Eng, L.E.; Chen, T.R.; Sanders, S.; Zhuang, Y.H.; Zhao, B.; Yariv, A. (Department of Applied Physics, California Institute of Technology, Pasadena, California 91125 (US)); Morkoc, H. (The Coordinated Science Laboratory, University of Illinois, Urbana, Illinois 61801)

    1989-10-02T23:59:59.000Z

    We report on low threshold current strained InGaAs/AlGaAs single quantum well lasers grown by molecular beam epitaxy. Broad-area threshold current densities of 114 A/cm{sup 2} at 990 nm were measured for 1540-{mu}m-long lasers. Threshold currents of 2.4 mA at 950 nm were obtained for an uncoated buried-heterostructure device with a 2-{mu}m-wide stripe and 425-{mu}m-long cavity. With reflective coatings the best device showed 0.9 mA threshold current ({ital L}=225 {mu}m). Preliminary modulation measurements show bandwidths up to 5.5 GHz limited by the detector response.

  7. Wide Area Camera Calibration Using Virtual Calibration Objects

    E-Print Network [OSTI]

    Stanford University

    Wide Area Camera Calibration Using Virtual Calibration Objects Xing Chen, James Davis, Philipp}@graphics.stanford.edu Abstract This paper introduces a method to calibrate a wide area system of unsynchronized cameras construction of a large calibration object. The user need only wave an identifiable point in front of all

  8. Using the World Wide Web Learning Communities in K-12

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    3.95 #12;commonly perform. Essential to all types of learning communities is access to resourcesUsing the World Wide Web to Build Learning Communities in K-12 Douglas N. Gordin, Louis M. Gomez in Learning Communities 3. The World Wide Web 4. Access to Resources 5. Access to Analysis Tools and Raw Data

  9. World Wide WebWWWDeep Web Web Deep Web

    E-Print Network [OSTI]

    Deep Web Web World Wide WebWWWDeep Web Web Deep Web Deep Web Deep Web Deep Web Deep Web 1 World Wide Web [1] Web 200,000TB Web Web Web Internet Web Web Web "" Surface Web Deep Web Surface Web 21.3% Surface Web Deep Web [2] Deep Web Web Crawler Deep Web 1 Web

  10. How Big Is the World Wide Web? Adrian Dobra

    E-Print Network [OSTI]

    How Big Is the World Wide Web? Adrian Dobra Department of Statistics Carnegie Mellon University of sound proce­ dures for assessing the size of the World Wide Web. The problem is compounded by the fact that sampling directly from the Web is not possible. Several groups of re­ searchers have found sampling schemes

  11. Phases of Atom-Molecule Vortex Matter

    SciTech Connect (OSTI)

    Woo, S. J.; Bigelow, N. P. [Department of Physics and Astronomy, University of Rochester, Rochester, New York (United States); Park, Q-Han [Department of Physics, Korea University, Seoul (Korea, Republic of)

    2008-03-28T23:59:59.000Z

    We study ground state vortex configurations in a rotating atom-molecule Bose-Einstein condensate. It is found that the coherent coupling between the atomic and molecular condensates can render a pairing of atomic and molecular vortices into a composite structure that resembles a carbon dioxide molecule. Structural phase transitions of vortex lattices are also explored through different physical parameters including the rotational frequency of the system.

  12. Method for enhanced atomization of liquids

    DOE Patents [OSTI]

    Thompson, Richard E. (27121 Puerta del Oro, Mission Viejo, CA 92691); White, Jerome R. (44755 Wyandotte, Hemet, CA 92544)

    1993-01-01T23:59:59.000Z

    In a process for atomizing a slurry or liquid process stream in which a slurry or liquid is passed through a nozzle to provide a primary atomized process stream, an improvement which comprises subjecting the liquid or slurry process stream to microwave energy as the liquid or slurry process stream exits the nozzle, wherein sufficient microwave heating is provided to flash vaporize the primary atomized process stream.

  13. CERTIFICATION DOCKET WESTINGHOUSE ATOMIC POWER DEVELOPMENT PLANT

    Office of Legacy Management (LM)

    Westinghouse Atomic 1 U.S. Department of Energy Interim Residual Contamination and Waste Control Guidelines for bormerly Utilized Sites Remedial Action Program (FUSRAP) d Remote...

  14. Atomic Energy and Nuclear Materials Program (Tennessee)

    Broader source: Energy.gov [DOE]

    The Atomic Energy and Nuclear Materials section of the Tennessee Code covers all of the regulations, licenses, permits, siting requirements, and practices relevant to a nuclear energy development. ...

  15. Classical and Quantum Chaos in Atom Optics

    E-Print Network [OSTI]

    Farhan Saif

    2006-04-10T23:59:59.000Z

    The interaction of an atom with an electromagnetic field is discussed in the presence of a time periodic external modulating force. It is explained that a control on atom by electromagnetic fields helps to design the quantum analog of classical optical systems. In these atom optical systems chaos may appear at the onset of external fields. The classical and quantum chaotic dynamics is discussed, in particular in an atom optics Fermi accelerator. It is found that the quantum dynamics exhibits dynamical localization and quantum recurrences.

  16. United States Atomic Energy Commission formed

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

    weapons problem, the United States worked to establish its own formal organization. The transition from military civilian control of nuclear energy was defined in the Atomic...

  17. Distribution Category: Atomic, Molecular, and Chemical Physics

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

    Atomic, Molecular, and Chemical Physics (UC-411) ARGONNE NATIONAL LABORATORY 9700 South Cass Avenue Argonne, TIlinois 60439 ANLI APSILS-151 RESULTS OF DESIGN CALCULATIONS FOR THE...

  18. Remote preparation of an atomic quantum memory

    E-Print Network [OSTI]

    Wenjamin Rosenfeld; Stefan Berner; Juergen Volz; Markus Weber; Harald Weinfurter

    2006-08-29T23:59:59.000Z

    Storage and distribution of quantum information are key elements of quantum information processing and quantum communication. Here, using atom-photon entanglement as the main physical resource, we experimentally demonstrate the preparation of a distant atomic quantum memory. Applying a quantum teleportation protocol on a locally prepared state of a photonic qubit, we realized this so-called remote state preparation on a single, optically trapped 87Rb atom. We evaluated the performance of this scheme by the full tomography of the prepared atomic state, reaching an average fidelity of 82%.

  19. Gas Atomization of Stainless Steel - Slow Motion

    SciTech Connect (OSTI)

    None

    2011-01-01T23:59:59.000Z

    Stainless steel liquid atomized by supersonic argon gas into a spray of droplets at ~1800ºC. Atomization of metal requires high pressure gas and specialized chambers for cooling and collecting the powders without contamination. The critical step for morphological control is the impingement of the gas on the melt stream. The video is a black and white high speed video of a liquid metal stream being atomized by high pressure gas. This material was atomized at the Ames Laboratory's Materials Preparation Center http://www.mpc.ameslab.gov

  20. Subwavelength Transportation of Light with Atomic Resonances

    E-Print Network [OSTI]

    Chui, Siu-Tat; Jo, Gyu-Boong

    2015-01-01T23:59:59.000Z

    We propose and investigate a new type of optical waveguide made by an array of atoms without involving conventional Bragg scattering or total internal reflection. A finite chain of atoms collectively coupled through their intrinsic resonance supports a propagating mode with minimal radiative loss when the array spacing $a$ is around 0.6$\\lambda_0/2\\pi$ where $\\lambda_0$ is the wavelength of the nearly resonant optical transition. We find that the transportation is robust with respect to position fluctuation and remains possible when the atoms are placed on a circle. Our result paves the way to implement the subwavelength transportation of light in integrated optical circuits with cold atoms.

  1. Photoluminescence polarization anisotropy for studying long-range structural ordering within semiconductor multi-atomic alloys and organic crystals

    SciTech Connect (OSTI)

    Prutskij, T.; Percino, J. [Instituto de Ciencias, BUAP, Privada 17 Norte, No 3417, col. San Miguel Huyeotlipan, 72050, Puebla, Pue. (Mexico); Orlova, T. [Department of Chemical and Biochemical Engineering, University of Notre Dame, Notre Dame, IN (United States); Vavilova, L. [Ioffe Physical-Technical Institute, 26 Polytekhnicheskaya, St Petersburg 194021, Russian Federation (Russian Federation)

    2013-12-04T23:59:59.000Z

    Long-range structural ordering within multi-component semiconductor alloys and organic crystals leads to significant optical anisotropy and, in particular, to anisotropy of the photoluminescence (PL) emission. The PL emission of ternary and quaternary semiconductor alloys is polarized if there is some amount of the atomic ordering within the crystal structure. We analyze the polarization of the PL emission from the quaternary GaInAsP semiconductor alloy grown by Liquid Phase Epitaxy (LPE) and conclude that it could be caused by low degree atomic ordering within the crystal structure together with the thermal biaxial strain due to difference between the thermal expansion coefficients of the layer and the substrate. We also study the state of polarization of the PL from organic crystals in order to identify different features of the crystal PL spectrum.

  2. CARBON ATOM DISTRIBUTION IN A DUAL PHASE STEEL: AN ATOM PROBE STUDY

    E-Print Network [OSTI]

    Barnard, S.J.

    2014-01-01T23:59:59.000Z

    ATOM DISTRIBUTION IN A DUAL PHASE STEEL: AN ATOM PROBE STUDY~4720 1 U.S.A. IntroductioE. Dual Phase steels are currentlymartensite-austenite dual phase steel, although the results

  3. Vibrational Modes of Adsorbed Atoms

    E-Print Network [OSTI]

    LAWRENCE, WR; Allen, Roland E.

    1977-01-01T23:59:59.000Z

    of adsorbed atoms. vi rational modes *Present address: S h University of H c ool of Scienc City, Tex. ouston at Clear La ', r e e and Technology Lake City, Clea Lak %. R. wrence and R. E. Allen published). Allen, Phys. Rev. B (to be 2G. P... are about t r Ne on Kr. The d ou he same as fo mode labeled 2V a as large in the f' t X is almost erst (adsorbate) la e od( b t t)l pure surface mod e ayer. The 1H mode at X is a 4, this mode bec m e. Just to the r'right of X in Fig. e ecomes a...

  4. Polymer electrolyte fuel cell electrodes grown by vapor deposition techniques Pascal Brault*

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Polymer electrolyte fuel cell electrodes grown by vapor deposition techniques Pascal Brault Abstract: Polymer fuel cell electrode growth using vapor deposition techniques is reviewed. The supports process: sputtering, CVD, PECVD, MOCVD. In each case, up-to-date fuel cell performances are highlighted

  5. Raman and Photoluminescence Spectroscopy of Nanocrystalline Diamond Films grown by Hot Filament CVD

    E-Print Network [OSTI]

    Bristol, University of

    H4 flow-rate ratio of standard polycrystalline diamond deposition parameters on formationRaman and Photoluminescence Spectroscopy of Nanocrystalline Diamond Films grown by Hot Filament CVD of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia b,c Diamond Research Laboratory, School

  6. WRINKLING OF a-ALUMINA FILMS GROWN BY OXIDATIONII. OXIDE SEPARATION AND FAILURE

    E-Print Network [OSTI]

    Clarke, David R.

    of thermal cycling on these modes of separation and how they may lead to oxide spalling are discussed. # 1998WRINKLING OF a-ALUMINA FILMS GROWN BY OXIDATIONÐII. OXIDE SEPARATION AND FAILURE V. K. TOLPYGO oxidation and cooling to room temperature. One type is a form of buckling where the size of the detached

  7. Direct Physical Exfoliation of Few-Layer Graphene from Graphite Grown on a Nickel Foil Using

    E-Print Network [OSTI]

    Maruyama, Shigeo

    Direct Physical Exfoliation of Few-Layer Graphene from Graphite Grown on a Nickel Foil Using Physical graphene exfoliation from graphite using optimized PDMS PACS codes: 68.65.Pq, 81.05.ue, 81.05.uf for the site-specific direct physical exfoliation of few-layer graphene sheets from cheap and easily

  8. Nonlithographic epitaxial SnxGe1x dense nanowire arrays grown on Ge,,001...

    E-Print Network [OSTI]

    Atwater, Harry

    Nonlithographic epitaxial SnxGe1Àx dense nanowire arrays grown on Ge,,001... Regina Ragan-thick SnxGe1 x /Ge(001) epitaxial films with 0 x 0.085 by molecular-beam epitaxy. These films evolve during growth into a dense array of SnxGe1 x nanowires oriented along 001 , as confirmed by composition contrast

  9. Few Graphene layer/Carbon-Nanotube composite Grown at CMOS-compatible Temperature

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    the growth of the recently demonstrated composite material composed of vertically aligned carbon nanotubesFew Graphene layer/Carbon-Nanotube composite Grown at CMOS-compatible Temperature V. Jousseaume1 materials and technologies for the next-generation of Integrated Circuits (ICs). Carbon nanomaterials

  10. INVESTIGATION OF ELECTRIC CONDITIONS IN THE VICINITY OF CARBON NANOTUBES GROWN IN A DC PLASMA SHEATH

    E-Print Network [OSTI]

    Boyer, Edmond

    nanotubes (CNTs ­ long tubular carbon nanostructures) belong to the best electron field emitting materials, such as nanoelectronics devices or mechanical reinforcement in composite materials [2,3]. The field emission propertiesINVESTIGATION OF ELECTRIC CONDITIONS IN THE VICINITY OF CARBON NANOTUBES GROWN IN A DC PLASMA

  11. THE RATCHETING OF COMPRESSED THERMALLY GROWN THIN FILMS ON DUCTILE SUBSTRATES

    E-Print Network [OSTI]

    Hutchinson, John W.

    THE RATCHETING OF COMPRESSED THERMALLY GROWN THIN FILMS ON DUCTILE SUBSTRATES M. Y. HE1 , A. G by oxidation of the substrate. It is shown that, in some circumstances, ratcheting occurs, wherein which ratcheting does not occur. This critical size is related to the expansion mis®t, the substrate

  12. Sonochemically grown ZnO nanowalls on Graphene layers as Photoanode in Dye sensitized Solar cells.

    E-Print Network [OSTI]

    Pala, Nezih

    Sonochemically grown ZnO nanowalls on Graphene layers as Photoanode in Dye sensitized Solar cells whole solar spectrum Graphene can be a very promising material in Dye Sensitized Solar cells (DSSC as photoanode is presented. The effect of Graphene on dye loading and on efficiency of DSSC is quantitatively

  13. Eumelanin Dye-sensitized Solar Cell Grown with Matrix-assisted Pulsed Laser

    E-Print Network [OSTI]

    Eumelanin Dye-sensitized Solar Cell Grown with Matrix-assisted Pulsed Laser Evaporation~4 DHICA DHICA #12; III Abstract At present the majority dye-sensitized solar cell research all, and besides provides and does not have other uses for the dye-sensitized solar cell use. In order to improve

  14. Ris Energy Report 3 Interest in the hydrogen economy has grown rapidly in

    E-Print Network [OSTI]

    1 Risø Energy Report 3 Interest in the hydrogen economy has grown rapidly in recent years. Those explains the current R&D situation, addresses the challenges facing the large-scale use of hydrogen countries with long traditions of activity in hydrogen research and development have now been joined

  15. Europium and samarium doped calcium sulfide thin films grown by PLD S. Christoulakis a,c

    E-Print Network [OSTI]

    Europium and samarium doped calcium sulfide thin films grown by PLD S. Christoulakis a,c , M Suchea Abstract Europium and samarium doped calcium sulfide thin films (CaS:Eu,Sm) with different thickness were and crystallinity. In this work we present preliminary results related to the deposition of europium and samarium

  16. VOLUME 76, NUMBER 24 P H Y S I C A L R E V I E W L E T T E R S 10 JUNE 1996 Observation of Atomic Wannier-Stark Ladders in an Accelerating Optical Potential

    E-Print Network [OSTI]

    Texas at Austin. University of

    Wannier-Stark Ladders in an Accelerating Optical Potential S. R. Wilkinson, C. F. Bharucha, K. W. Madison.50.Vk, 71.70.Ej Motion of ultracold atoms in optical lattices formed by interfering beams of light has-resonant optical lattices, where the internal atomic structure plays an important role, and a wide range

  17. Measurement of positional isotope exchange rates in enzyme catalyzed reactions by fast atom bombardment mass spectrometry 

    E-Print Network [OSTI]

    Hilscher, Larry Wayne

    1985-01-01T23:59:59.000Z

    utility in analyzing a wide array of biological compounds. Our laboratory became interested in the potential use of FAB-MS to study PIX in nucleotide . Working with Dr. David H. Russell's group (Dept. of Chemistry, Texas A A M University) we were able...MEASUREMENT OF POSITIONAL ISOTOPE EXCHANGE RATES IN ENZYME CATALYZED REACTIONS BY FAST ATOM BOMBARDMENT MASS SPECTROMETRY A Thesis by LARRY NAYNE HILSCHER Submitted to the Gradu te College of Texas A&M University in partial fulfil" mert...

  18. Atomic Safety and Licensing Board Panel annual report, Fiscal year 1992

    SciTech Connect (OSTI)

    Not Available

    1993-09-01T23:59:59.000Z

    In Fiscal Year 1992, the Atomic Safety and Licensing Board Panel (``the Panel``) handled 38 proceedings. The cases addressed issues in the construction, operation, and maintenance of commercial nuclear power reactors and other activities requiring a license from the Nuclear Regulatory Commission. This reports sets out the Panel`s caseload during the year and summarizes, highlights, and analyzes how the wide-ranging issues raised in those proceedings were addressed by the Panel`s judges and licensing boards.

  19. CoSe2 Nanoparticles Grown on Carbon Fiber Paper: An Efficient and Stable Electrocatalyst for Hydrogen Evolution Reaction

    E-Print Network [OSTI]

    Cui, Yi

    are designed to function in acidic electrolyte, in which the state- of-the-art hydrogen-producing catalystsCoSe2 Nanoparticles Grown on Carbon Fiber Paper: An Efficient and Stable Electrocatalyst-dimensional electrodes composed of CoSe2 nanoparticles grown on carbon fiber paper. The electrode exhibits excellent

  20. Digestion of milk protein and methanol-grown bacteria protein in the preruminant calf. II. Amino acid composition of

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Digestion of milk protein and methanol-grown bacteria protein in the preruminant calf. II. Amino of milk and of methanol-grown bacteria in the terminal small intestine and the hindgut of the preruminant exclusively by skim-milk powder ; 50.5 p. 100 of the protein of the bacte- ria diet was supplied by methanol

  1. Edge-emission electroluminescence study of as-grown vertical-cavity surface-emitting laser structures

    E-Print Network [OSTI]

    Ghosh, Sandip

    Edge-emission electroluminescence study of as-grown vertical-cavity surface-emitting laser 22 April 2000 We report polarized edge- and front-emission electroluminescence studies on red on pieces of as-grown wafers using indium­tin­oxide-coated glass electrodes. The front-emission spectra

  2. Epitaxial TiN,,001... Grown and Analyzed In situ by XPS and UPS. II. Analysis of Ar

    E-Print Network [OSTI]

    Gall, Daniel

    Epitaxial TiN,,001... Grown and Analyzed In situ by XPS and UPS. II. Analysis of Ar¿ Sputter Etched and UPS were used to study epitaxial TiN 001 layers grown in situ which were Ar sputter etched. The films Host Material: epitaxial TiN(001) thin film sputter etched Instrument: Physical Electronics, Inc. 5400

  3. Epitaxial TiN,,001... Grown and Analyzed In situ by XPS and UPS. I. Analysis of

    E-Print Network [OSTI]

    Gall, Daniel

    Epitaxial TiN,,001... Grown and Analyzed In situ by XPS and UPS. I. Analysis of As-deposited Layers used to characterize as- deposited epitaxial TiN 001 layers grown in situ. The films were deposited, while the UPS data was generated by He I and He II UV radiation. The spectra show that the TiN 001

  4. Scanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Epitaxy

    E-Print Network [OSTI]

    on sapphire substrate [2]. Park et al. performed the growth of Cr doped GaN single crystal by sodium fluxScanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Orleans, New Orleans, LA 70148, USA Abstract: Cr doped GaN was grown by rf N-plasma molecular beam epitaxy

  5. Correlation between structural properties and optical amplification in InGaN/GaN heterostructures grown by molecular beam epitaxy

    E-Print Network [OSTI]

    Nabben, Reinhard

    . The lateral homogeneity can be drastically improved using a template of GaN grown on the sapphire substrate-grown heterostructures can drastically be reduced by using a template of MOVPE-GaN on the sapphire substrate, which leadsCorrelation between structural properties and optical amplification in InGaN/GaN heterostructures

  6. A Comparison of Magnesium and Beryllium Acceptors in GaN Grown by rf-Plasma Assisted Molecular Beam Epitaxy

    E-Print Network [OSTI]

    Myers, Tom

    as a function of substrate temperature and dopant flux for Ga-polarity and N-polarity GaN. Incorporation GaN templates on (0001) sapphire substrates. The doped layers were grown at a rate of 0.25 µmA Comparison of Magnesium and Beryllium Acceptors in GaN Grown by rf-Plasma Assisted Molecular Beam

  7. Relativistic atomic physics at the SSC

    SciTech Connect (OSTI)

    NONE

    1990-12-31T23:59:59.000Z

    This report discusses the following proposed work for relativistic atomic physics at the Superconducting Super Collider: Beam diagnostics; atomic physics research; staffing; education; budget information; statement concerning matching funds; description and justification of major items of equipment; statement of current and pending support; and assurance of compliance.

  8. Atomic processes in high-density plasmas

    SciTech Connect (OSTI)

    More, R.M.

    1982-12-21T23:59:59.000Z

    This review covers dense atomic plasmas such as that produced in inertial confinement fusion. The target implosion physics along with the associated atomic physics, i.e., free electron collision phenomena, electron states I, electron states II, and nonequilibrium plasma states are described. (MOW)

  9. Interaction of trapped ions with trapped atoms

    E-Print Network [OSTI]

    Grier, Andrew T. (Andrew Todd)

    2011-01-01T23:59:59.000Z

    In this thesis, I present results from two Paul-trap based ion traps carried out in the Vuleti? laboratory: the Atom-Ion trap for collision studies between cold atoms and cold ions, and the Cavity-Array trap for studying ...

  10. Photoassociative molecular spectroscopy for atomic radiative lifetimes.

    E-Print Network [OSTI]

    Boyer, Edmond

    very far apart, in so-called long- range molecular states, their mutual interaction is ruled by plain atomic properties. The high- resolution spectroscopic study of some molecular excited states populated by photoassociation of cold atoms (photoassociative spectroscopy) gives a good illustration of this property

  11. A wide-dynamic-range time-based CMOS imager

    E-Print Network [OSTI]

    O'Halloran, Micah G. (Micah Galletta), 1978-

    2008-01-01T23:59:59.000Z

    This thesis describes a novel dual-threshold time-based current sensing algorithm suitable for use in wide-dynamic-range CMOS imagers. A prototype 150 x 256 pixel imager employing this algorithm experimentally achieves ...

  12. Section S Summary of the Site-Wide Environmental Assessment

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Degradation Due to the Locations and Designs of New Facilities and Associated Lighting, Especially on Top of South Table Mountain. Final EA Page S-4 July 2003 Site-Wide...

  13. Chemistry & Biology Genome-Wide High-Throughput Mining

    E-Print Network [OSTI]

    Yin, Jun

    Chemistry & Biology Article Genome-Wide High-Throughput Mining of Natural-Product Biosynthetic Gene.01.006 SUMMARY We have developed a phage-display method for high-throughput mining of bacterial gene clus- ters

  14. Department-wide Quick Reaction Work Order System

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    1981-03-12T23:59:59.000Z

    To describe the new Department Wide Quick Reaction Work Order System, to establish the criteria and procedures for its use, and to identify responsibilities for managing and operating the system.

  15. Variable rate CELP speech coding using widely variable parameter updates

    E-Print Network [OSTI]

    Moodie, Myron L.

    1995-01-01T23:59:59.000Z

    bit rates for a given quality level. This work develops new techniques, referred to as widely variable CELP parameter updates, which dynamically adapt the transmit frequency of the CELP spectral parameters to the characteristics of the input speech...

  16. Social Network Theory, Broadband and the World Wide Web

    E-Print Network [OSTI]

    Sgroi, Daniel

    2006-03-14T23:59:59.000Z

    This paper aims to predict some possible futures for the World Wide Web based on several key network parameters: size, complexity, cost and increasing connection speed thorough the uptake of broadband technology. This is done through the production...

  17. Genome-wide analyses using bead-based microarrays

    E-Print Network [OSTI]

    Dunning, Mark J

    2008-09-04T23:59:59.000Z

    Microarrays are now an established tool for biological research and have a wide range of applications. In this thesis I investigate the BeadArray microarray technology developed by Illumina. The design of this technology is unique and gives rise...

  18. A Study of Transport Protocols for Wide Area Scientific Applications

    SciTech Connect (OSTI)

    Vishal Misra

    2011-03-01T23:59:59.000Z

    This is the final project report of award "A Study of Transport Protocols for Wide Area Scientific Applications", given by DOE in 2003 to Vishal Misra at Columbia University.

  19. DOE/OIT Plant-Wide Energy Assessment Experience Summary

    E-Print Network [OSTI]

    Olszewski, M.; Leach, R.; McElhaney, K.

    The Department of Energy (DOE) Office of Industrial Technologies (OIT) is sponsoring cost-shared, plant-wide energy assessments of industrial facilities through its BestPractices Program. The purpose of these assessments is to examine plant utility...

  20. Sagnac interferometry with a single atomic clock

    E-Print Network [OSTI]

    Stevenson, R; Bishop, T; Lesanovsky, I; Fernholz, T

    2015-01-01T23:59:59.000Z

    We theoretically discuss an implementation of a Sagnac interferometer with cold atoms. In contrast to currently existing schemes our protocol does not rely on any free propagation of atoms. Instead it is based on superpositions of fully confined atoms and state-dependent transport along a closed path. Using Ramsey sequences for an atomic clock, the accumulated Sagnac phase is encoded in the resulting population imbalance between two internal (clock) states. Using minimal models for the above protocol we analytically quantify limitations arising from atomic dynamics and finite temperature. We discuss an actual implementation of the interferometer with adiabatic radio-frequency potentials that is inherently robust against common mode noise as well as phase noise from the reference oscillator.

  1. Sagnac interferometry with a single atomic clock

    E-Print Network [OSTI]

    R. Stevenson; M. Hush; T. Bishop; I. Lesanovsky; T. Fernholz

    2015-04-21T23:59:59.000Z

    We theoretically discuss an implementation of a Sagnac interferometer with cold atoms. In contrast to currently existing schemes our protocol does not rely on any free propagation of atoms. Instead it is based on superpositions of fully confined atoms and state-dependent transport along a closed path. Using Ramsey sequences for an atomic clock, the accumulated Sagnac phase is encoded in the resulting population imbalance between two internal (clock) states. Using minimal models for the above protocol we analytically quantify limitations arising from atomic dynamics and finite temperature. We discuss an actual implementation of the interferometer with adiabatic radio-frequency potentials that is inherently robust against common mode noise as well as phase noise from the reference oscillator.

  2. Snap: Robust Tool for Internet-wide Operating System Fingerprinting

    E-Print Network [OSTI]

    Nandwani, Ankur Bharatbhushan

    2012-02-14T23:59:59.000Z

    SNAP: ROBUST TOOL FOR INTERNET-WIDE OPERATING SYSTEM FINGERPRINTING A Thesis by ANKUR BHARATBHUSHAN NANDWANI Submitted to the O?ce of Graduate Studies of Texas A&M University in partial fulflllment of the requirements for the degree... of MASTER OF SCIENCE December 2010 Major Subject: Computer Science SNAP: ROBUST TOOL FOR INTERNET-WIDE OPERATING SYSTEM FINGERPRINTING A Thesis by ANKUR BHARATBHUSHAN NANDWANI Submitted to the O?ce of Graduate Studies of Texas A&M University...

  3. A Wide Temperature Range Cryostat for Polarised Target Material Preparation

    E-Print Network [OSTI]

    Dutz, Hartmut

    with current I and target density nt t 1 f 2 · P2 t · L · A2 t FOM = f 2 · P2 t · L is defining quality of frequency e + p DNP requirement: N Tn Te n Scott Reeve Wide Temperature · T Linear dependence of m on P laminar flow profile Falmer Scott Reeve Wide Temperature Range Cryostat 11

  4. Epitaxial two-dimensional nitrogen atomic sheet in GaAs

    SciTech Connect (OSTI)

    Harada, Yukihiro, E-mail: y.harada@eedept.kobe-u.ac.jp; Yamamoto, Masuki; Baba, Takeshi; Kita, Takashi [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan)

    2014-01-27T23:59:59.000Z

    We have grown an epitaxial two-dimensional nitrogen (N) atomic sheet in GaAs by using the site-controlled N ?-doping technique. We observed a change of the electronic states in N ?-doped GaAs from the isolated impurity centers to the delocalized impurity band at 1.49?eV with increasing N-doping density. According to the excitation-power- and temperature-dependent photoluminescence (PL) spectra, the emission related to localized levels below the impurity band edge was dominant at low excitation power and temperature, whereas the effects of the localized levels can be neglected by increasing the excitation power and temperature. Furthermore, a clear Landau shift of the PL-peak energy was observed at several Tesla in the Faraday configuration, in contrast to the case in the impurity limit.

  5. High sensitive formaldehyde graphene gas sensor modified by atomic layer deposition zinc oxide films

    SciTech Connect (OSTI)

    Mu, Haichuan; Zhang, Zhiqiang; Wang, Keke; Xie, Haifen, E-mail: hfxie@ecust.edu.cn [Department of Physics, School of Science, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Zhao, Xiaojing; Liu, Feng [Department of Physics, Shanghai Normal University, 100 Guilin Road, Shanghai 200234 (China)

    2014-07-21T23:59:59.000Z

    Zinc oxide (ZnO) thin films with various thicknesses were fabricated by Atomic Layer Deposition on Chemical Vapor Deposition grown graphene films and their response to formaldehyde has been investigated. It was found that 0.5?nm ZnO films modified graphene sensors showed high response to formaldehyde with the resistance change up to 52% at the concentration of 9 parts-per-million (ppm) at room temperature. Meanwhile, the detection limit could reach 180 parts-per-billion (ppb) and fast response of 36?s was also obtained. The high sensitivity could be attributed to the combining effect from the highly reactive, top mounted ZnO thin films, and high conductive graphene base network. The dependence of ZnO films surface morphology and its sensitivity on the ZnO films thickness was also investigated.

  6. Fast atom diffraction from a ?-Ga{sub 2}O{sub 3}(100) surface

    SciTech Connect (OSTI)

    Busch, M.; Meyer, E.; Winter, H. [Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, D-12489 Berlin (Germany); Irmscher, K.; Galazka, Z. [Leibniz-Institut für Kristallzüchtung, Max-Born-Straße 2, D-12489 Berlin (Germany); Gärtner, K. [Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, D-07743 Jena (Germany)

    2014-08-04T23:59:59.000Z

    Fast H, He atoms, and H{sub 2} molecules with projectile energies ranging from 200?eV up to 3?keV were scattered under a grazing angle of incidence from a clean and flat ?-Ga{sub 2}O{sub 3}(100) surface. The bulk single crystal was grown by the Czochralski method and prepared via annealing under ultra-high vacuum conditions. For scattering along low-index directions, we observed defined diffraction patterns in the angular distributions for scattered projectiles. From the analysis of diffraction patterns, we derive the surface unit cell in good accord with the parameters b and c for the lattice of the bulk crystal and derive information on the termination of the surface.

  7. Investigation of leakage current paths in n-GaN by conductive atomic force microscopy

    SciTech Connect (OSTI)

    Kim, Bumho; Park, Yongjo, E-mail: yp0520@snu.ac.kr, E-mail: eyoon@snu.ac.kr [Energy Semiconductor Research Center, Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270 (Korea, Republic of)] [Energy Semiconductor Research Center, Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270 (Korea, Republic of); Moon, Daeyoung; Nanishi, Yasushi [WCU Hybrid Materials Program, Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of)] [WCU Hybrid Materials Program, Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Joo, Kisu [Energy Semiconductor Research Center, Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270 (Korea, Republic of) [Energy Semiconductor Research Center, Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270 (Korea, Republic of); Department of Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Suwon 443-270 (Korea, Republic of); Oh, Sewoung [Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of)] [Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, Young Kuk [Korea Research Institute of Chemical Technology, Daejon 305-600 (Korea, Republic of)] [Korea Research Institute of Chemical Technology, Daejon 305-600 (Korea, Republic of); Yoon, Euijoon, E-mail: yp0520@snu.ac.kr, E-mail: eyoon@snu.ac.kr [Energy Semiconductor Research Center, Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270 (Korea, Republic of) [Energy Semiconductor Research Center, Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270 (Korea, Republic of); WCU Hybrid Materials Program, Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Department of Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Suwon 443-270 (Korea, Republic of); Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2014-03-10T23:59:59.000Z

    We have investigated electrical characteristics of leakage current paths in n-GaN layer grown by metal-organic chemical vapor deposition with conductive-atomic force microscopy (C-AFM). The C-AFM mapping shows two kinds of leakage current paths existing in the n-GaN layer: open-core dislocation and pure screw dislocation. From the localized I-V curves measured by C-AFM, we confirmed that the open-core screw dislocation shows more significant leakage current. We explained these results in terms of a modified Schottky band model based on donor states formed by oxygen segregation at the (10?10) sidewall of the open-core screw dislocation.

  8. Atmospheric pressure spatial atomic layer deposition web coating with in situ monitoring of film thickness

    SciTech Connect (OSTI)

    Yersak, Alexander S.; Lee, Yung C. [Department of Mechanical Engineering, University of Colorado at Boulder, 1045 Regent Drive, 422 UCB, Boulder, Colorado 80309-0422 (United States); Spencer, Joseph A.; Groner, Markus D., E-mail: mgroner@aldnanosolutions.com [ALD NanoSolutions, Inc., 580 Burbank Street, Unit 100, Broomfield, Colorado 80020 (United States)

    2014-01-15T23:59:59.000Z

    Spectral reflectometry was implemented as a method for in situ thickness monitoring in a spatial atomic layer deposition (ALD) system. Al{sub 2}O{sub 3} films were grown on a moving polymer web substrate at 100?°C using an atmospheric pressure ALD web coating system, with film growth of 0.11–0.13?nm/cycle. The modular coating head design and the in situ monitoring allowed for the characterization and optimization of the trimethylaluminum and water precursor exposures, purge flows, and web speed. A thickness uniformity of ±2% was achieved across the web. ALD cycle times as low as 76?ms were demonstrated with a web speed of 1?m/s and a vertical gap height of 0.5?mm. This atmospheric pressure ALD system with in situ process control demonstrates the feasibility of low-cost, high throughput roll-to-roll ALD.

  9. On the energy of electric field in hydrogen atom

    E-Print Network [OSTI]

    Yuri Kornyushin

    2009-07-30T23:59:59.000Z

    It is shown that hydrogen atom is a unique object in physics having negative energy of electric field, which is present in the atom. This refers also to some hydrogen-type atoms: hydrogen anti-atom, atom composed of proton and antiproton, and positronium.

  10. Engineering atom-atom thermal entanglement via two-photon process

    E-Print Network [OSTI]

    Y. Q. Guo; L. Zhou; H. S. Song

    2005-09-21T23:59:59.000Z

    We study the system that two atoms simultaneously interact with a single-mode thermal field via different couplings and different spontaneous emission rates when two-photon process is involved. It is found that we indeed can employ the different couplings to produce the atom-atom thermal entanglement in two-photon process. The different atomic spontaneous emission rates are also utilizable in generating thermal entanglement. We also investigate the effect of the cavity leakage. To the initial atomic state $|ee> ,$a slight leakage can relieve the restriction of interaction time and we can obtain a large and steady entanglement.

  11. Laser trapping of {sup 21}Na atoms

    SciTech Connect (OSTI)

    Lu, Zheng-Tian

    1994-09-01T23:59:59.000Z

    This thesis describes an experiment in which about four thousand radioactive {sup 21}Na (t{sub l/2} = 22 sec) atoms were trapped in a magneto-optical trap with laser beams. Trapped {sup 21}Na atoms can be used as a beta source in a precision measurement of the beta-asymmetry parameter of the decay of {sup 21}Na {yields} {sup 21}Ne + {Beta}{sup +} + v{sub e}, which is a promising way to search for an anomalous right-handed current coupling in charged weak interactions. Although the number o trapped atoms that we have achieved is still about two orders of magnitude lower than what is needed to conduct a measurement of the beta-asymmetry parameter at 1% of precision level, the result of this experiment proved the feasibility of trapping short-lived radioactive atoms. In this experiment, {sup 21}Na atoms were produced by bombarding {sup 24}Mg with protons of 25 MeV at the 88 in. Cyclotron of Lawrence Berkeley Laboratory. A few recently developed techniques of laser manipulation of neutral atoms were applied in this experiment. The {sup 21}Na atoms emerging from a heated oven were first transversely cooled. As a result, the on-axis atomic beam intensity was increased by a factor of 16. The atoms in the beam were then slowed down from thermal speed by applying Zeeman-tuned slowing technique, and subsequently loaded into a magneto-optical trap at the end of the slowing path. The last two chapters of this thesis present two studies on the magneto-optical trap of sodium atoms. In particular, the mechanisms of magneto-optical traps at various laser frequencies and the collisional loss mechanisms of these traps were examined.

  12. Search for ultralight scalar dark matter with atomic spectroscopy

    E-Print Network [OSTI]

    Van Tilburg, Ken; Bougas, Lykourgos; Budker, Dmitry

    2015-01-01T23:59:59.000Z

    We report new limits on ultralight scalar dark matter (DM) with dilaton-like couplings to photons that can induce oscillations in the fine-structure constant alpha. Atomic dysprosium exhibits an electronic structure with two nearly degenerate levels whose energy splitting is sensitive to changes in alpha. Spectroscopy data for two isotopes of dysprosium over a two-year span is analyzed for coherent oscillations with angular frequencies below 1 rad/s. No signal consistent with a DM coupling is identified, leading to new constraints on dilaton-like photon couplings over a wide mass range. Under the assumption that the scalar field comprises all of the DM, our limits on the coupling exceed those from equivalence-principle tests by up to 4 orders of magnitude for masses below 3 * 10^-18 eV. Excess oscillatory power, inconsistent with fine-structure variation, is detected in a control data set, and is likely due to a systematic effect. Our atomic spectroscopy limits on DM are the first of their kind, and leave sub...

  13. Improved Energy Conversion Efficiency in Wide-Bandgap Cu(In,Ga)Se2 Solar Cells: Preprint

    SciTech Connect (OSTI)

    Contreras, M.; Mansfield, L.; Egaas, B.; Li, J.; Romero, M.; Noufi, R.; Rudiger-Voigt, E.; Mannstadt, W.

    2011-07-01T23:59:59.000Z

    This report outlines improvements to the energy conversion efficiency in wide bandgap (Eg>1.2 eV) solar cells based on CuIn1-xGaxSe2. Using (a) alkaline containing high temperature glass substrates, (b) elevated substrate temperatures 600?C-650?C and (c) high vacuum evaporation from elemental sources following NREL's three-stage process, we have been able to improve the performance of wider bandgap solar cells with 1.218% for absorber bandgaps ~1.30 eV and efficiencies ~16% for bandgaps up to ~1.45 eV. In comparing J-V parameters in similar materials, we establish gains in the open-circuit voltage and, to a lesser degree, the fill factor value, as the reason for the improved performance. The higher voltages seen in these wide gap materials grown at high substrate temperatures may be due to reduced recombination at the grain boundary of such absorber films. Solar cell results, absorber materials characterization, and experimental details are reported.

  14. Atomic magnetometer for human magnetoencephalograpy.

    SciTech Connect (OSTI)

    Schwindt, Peter; Johnson, Cort N.

    2010-12-01T23:59:59.000Z

    We have developed a high sensitivity (<5 fTesla/{radical}Hz), fiber-optically coupled magnetometer to detect magnetic fields produced by the human brain. This is the first demonstration of a noncryogenic sensor that could replace cryogenic superconducting quantum interference device (SQUID) magnetometers in magnetoencephalography (MEG) and is an important advance in realizing cost-effective MEG. Within the sensor, a rubidium vapor is optically pumped with 795 laser light while field-induced optical rotations are measured with 780 nm laser light. Both beams share a single optical axis to maximize simplicity and compactness. In collaboration with neuroscientists at The Mind Research Network in Albuquerque, NM, the evoked responses resulting from median nerve and auditory stimulation were recorded with the atomic magnetometer and a commercial SQUID-based MEG system with signals comparing favorably. Multi-sensor operation has been demonstrated with two AMs placed on opposite sides of the head. Straightforward miniaturization would enable high-density sensor arrays for whole-head magnetoencephalography.

  15. Exact theory and numeric results for short pulse ionization of simple model atom in one dimension

    E-Print Network [OSTI]

    Rokhlenko, Alexander

    2015-01-01T23:59:59.000Z

    Our exact theory for continuous harmonic perturbation of a one dimensional model atom by parametric variations of its potential is generalized for the cases when a) the atom is exposed to short pulses of an external harmonic electric field and b) the forcing is represented by short bursts of different shape changing the strength of the binding potential. This work is motivated not only by the wide use of laser pulses for atomic ionization, but also by our earlier study of the same model which successfully described the ionization dynamics in all orders, i.e. the multi-photon processes, though being treated by the non-relativistic Schr\\"odinger equation. In particular, it was shown that the bound atom cannot survive the excitation of its potential caused by any non-zero frequency and amplitude of the continuous harmonic forcing. Our present analysis found important laws of the atomic ionization by short pulses, in particular the efficiency of ionizing this model system and presumably real ones as well.

  16. Communication: Angular momentum alignment and fluorescence polarization of alkali atoms photodetached from helium nanodroplets

    SciTech Connect (OSTI)

    Hernando, Alberto; Beswick, J. Alberto; Halberstadt, Nadine [LCAR-IRSAMC, Université Toulouse 3 - Paul Sabatier and CNRS, 31062 Toulouse (France)] [LCAR-IRSAMC, Université Toulouse 3 - Paul Sabatier and CNRS, 31062 Toulouse (France)

    2013-12-14T23:59:59.000Z

    The theory of photofragments angular momentum polarization is applied to the photodetachment of an electronically excited alkali atom from a helium nanocluster (N = 200). The alignment of the electronic angular momentum of the bare excited alkali atoms produced is calculated quantum mechanically by solving the excited states coupled equations with potentials determined by density functional theory (DFT). Pronounced oscillations as a function of excitation energy are predicted for the case of Na@(He){sub 200}, in marked contrast with the absorption cross-section and angular distribution of the ejected atoms which are smooth functions of the energy. These oscillations are due to quantum interference between different coherently excited photodetachment pathways. Experimentally, these oscillations should be reflected in the fluorescence polarization and polarization-resolved photoelectron yield of the ejected atoms, which are proportional to the electronic angular momentum alignment. In addition, this result is much more general than the test case of NaHe{sub 200} studied here. It should be observable for larger droplets, for higher excited electronic states, and for other alkali as well as for alkali-earth atoms. Detection of these oscillations would show that the widely used pseudo-diatomic model can be valid beyond the prediction of absorption spectra and could help in interpreting parts of the dynamics, as already hinted by some experimental results on angular anisotropy of bare alkali fragments.

  17. Atomic Scale Design and Three-Dimensional Simulation of Ionic Diffusive Nanofluidic Channels

    E-Print Network [OSTI]

    Jin Kyoung Park; Kelin Xia; Guo-Wei We

    2015-03-02T23:59:59.000Z

    Recent advance in nanotechnology has led to rapid advances in nanofluidics, which has been established as a reliable means for a wide variety of applications, including molecular separation, detection, crystallization and biosynthesis. Although atomic and molecular level consideration is a key ingredient in experimental design and fabrication of nanfluidic systems, atomic and molecular modeling of nanofluidics is rare and most simulations at nanoscale are restricted to one- or two-dimensions in the literature, to our best knowledge. The present work introduces atomic scale design and three-dimensional (3D) simulation of ionic diffusive nanofluidic systems. We propose a variational multiscale framework to represent the nanochannel in discrete atomic and/or molecular detail while describe the ionic solution by continuum. Apart from the major electrostatic and entropic effects, the non-electrostatic interactions between the channel and solution, and among solvent molecules are accounted in our modeling. We derive generalized Poisson-Nernst-Planck (PNP) equations for nanofluidic systems. Mathematical algorithms, such as Dirichlet to Neumann mapping and the matched interface and boundary (MIB) methods are developed to rigorously solve the aforementioned equations to the second-order accuracy in 3D realistic settings. Three ionic diffusive nanofluidic systems, including a negatively charged nanochannel, a bipolar nanochannel and a double-well nanochannel are designed to investigate the impact of atomic charges to channel current, density distribution and electrostatic potential. Numerical findings, such as gating, ion depletion and inversion, are in good agreements with those from experimental measurements and numerical simulations in the literature.

  18. Scattering properties of dark atoms and molecules

    E-Print Network [OSTI]

    James M. Cline; Zuowei Liu; Guy D. Moore; Wei Xue

    2014-01-15T23:59:59.000Z

    There has been renewed interest in the possibility that dark matter exists in the form of atoms, analogous to those of the visible world. An important input for understanding the cosmological consequences of dark atoms is their self-scattering. Making use of results from atomic physics for the potentials between hydrogen atoms, we compute the low-energy elastic scattering cross sections for dark atoms. We find an intricate dependence upon the ratio of the dark proton to electron mass, allowing for the possibility to "design" low-energy features in the cross section. Dependences upon other parameters, namely the gauge coupling and reduced mass, scale out of the problem by using atomic units. We derive constraints on the parameter space of dark atoms by demanding that their scattering cross section does not exceed bounds from dark matter halo shapes. We discuss the formation of molecular dark hydrogen in the universe, and determine the analogous constraints on the model when the dark matter is predominantly in molecular form.

  19. Scattering properties of dark atoms and molecules

    E-Print Network [OSTI]

    Cline, James M; Moore, Guy; Xue, Wei

    2013-01-01T23:59:59.000Z

    There has been renewed interest in the possibility that dark matter exists in the form of atoms, analogous to those of the visible world. An important input for understanding the cosmological consequences of dark atoms is their self-scattering. Making use of results from atomic physics for the potentials between hydrogen atoms, we compute the low-energy elastic scattering cross sections for dark atoms. We find an intricate dependence upon the ratio of the dark proton to electron mass, allowing for the possibility to "design" low-energy features in the cross section. Dependences upon other parameters, namely the gauge coupling and reduced mass, scale out of the problem by using atomic units. We derive constraints on the parameter space of dark atoms by demanding that their scattering cross section does not exceed bounds from dark matter halo shapes. We discuss the formation of molecular dark hydrogen in the universe, and determine the analogous constraints on the model when the dark matter is predominantly in ...

  20. Ps-atom scattering at low energies

    E-Print Network [OSTI]

    Fabrikant, I I

    2015-01-01T23:59:59.000Z

    A pseudopotential for positronium-atom interaction, based on electron-atom and positron-atom phase shifts, is constructed, and the phase shifts for Ps-Kr and Ps-Ar scattering are calculated. This approach allows us to extend the Ps-atom cross sections, obtained previously in the impulse approximation [Phys. Rev. Lett. 112, 243201 (2014)], to energies below the Ps ionization threshold. Although experimental data are not available in this low-energy region, our results describe well the tendency of the measured cross sections to drop with decreasing velocity at $v<1$ a.u. Our results show that the effect of the Ps-atom van der Waals interaction is weak compared to the polarization interaction in electron-atom and positron-atom scattering. As a result, the Ps scattering length for both Ar and Kr is positive, and the Ramsauer-Townsend minimum is not observed for Ps scattering from these targets. This makes Ps scattering quite different from electron scattering in the low-energy region, in contrast to the inter...

  1. Studying coherence in ultra-cold atomic gases

    E-Print Network [OSTI]

    Miller, Daniel E. (Daniel Edward)

    2007-01-01T23:59:59.000Z

    This thesis will discuss the study of coherence properties of ultra-cold atomic gases. The atomic systems investigated include a thermal cloud of atoms, a Bose-Einstein condensate and a fermion pair condensate. In each ...

  2. 1984 Bibliography of atomic and molecular processes

    SciTech Connect (OSTI)

    Barnett, C.F.; Gilbody, H.B.; Gregory, D.C.; Griffin, P.M.; Havener, C.C.; Howard, A.M.; Kirkpatrick, M.I.; McDaniel, E.W.; Meyer, F.W.; Morgan, T.J. (comps.)

    1985-04-01T23:59:59.000Z

    This annotated bibliography includes papers on atomic and molecular processes published during 1984. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory.

  3. 1985 bibliography of atomic and molecular processes

    SciTech Connect (OSTI)

    Barnett, C.F.; Gilbody, H.B.; Gregory, D.C.; Griffin, P.M.; Havener, C.C.; Howald, A.M.; Kirkpatrick, M.I.; McDaniel, E.W.; Meyer, F.W.; Morgan, T.J. (comps.)

    1986-06-01T23:59:59.000Z

    This annotated bibliography includes papers on atomic and molecular processes published during 1985. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory.

  4. Gain narrowing in few-atom systems

    E-Print Network [OSTI]

    Tom Savels; Allard P. Mosk; Ad Lagendijk

    2006-05-31T23:59:59.000Z

    Using a density matrix approach, we study the simplest systems that display both gain and feedback: clusters of 2 to 5 atoms, one of which is pumped. The other atoms supply feedback through multiple scattering of light. We show that, if the atoms are in each other's near-field, the system exhibits large gain narrowing and spectral mode redistribution. The observed phenomena are more pronounced if the feedback is enhanced. Our system is to our knowledge the simplest exactly solvable microscopic system which shows the approach to laser oscillation.

  5. Cold Light from Hot Atoms and Molecules

    SciTech Connect (OSTI)

    Lister, Graeme [OSRAM SYLVANIA, CRSL, 71 Cherry Hill Drive, Beverly, MA (United States); Curry, John J. [National Institute of Standards and Technology, Gaithersburg, MD (United States)

    2011-05-11T23:59:59.000Z

    The introduction of rare earth atoms and molecules into lighting discharges led to great advances in efficacy of these lamps. Atoms such as Dy, Ho and Ce provide excellent radiation sources for lighting applications, with rich visible spectra, such that a suitable combination of these elements can provide high quality white light. Rare earth molecules have also proved important in enhancing the radiation spectrum from phosphors in fluorescent lamps. This paper reviews some of the current aspects of lighting research, particularly rare earth chemistry and radiation, and the associated fundamental atomic and molecular data.

  6. An Atom Trap Relying on Optical Pumping

    E-Print Network [OSTI]

    P. Bouyer; P. Lemonde; M. Ben Dahan; A. Michaud; C. Salomon; J. Dalibard

    2005-09-21T23:59:59.000Z

    We have investigated a new radiation pressure trap which relies on optical pumping and does not require any magnetic field. It employs six circularly polarized divergent beams and works on the red of a $J_{g} \\longrightarrow J_{e} = J_{g} + 1$ atomic transition with $J_{g} \\geq 1/2$. We have demonstrated this trap with cesium atoms from a vapour cell using the 852 nm $J_{g} = 4 \\longrightarrow J_{e} = 5$ resonance transition. The trap contained up to $3 \\cdot 10^{7}$ atoms in a cloud of $1/\\sqrt{e}$ radius of 330 $\\mu$m.

  7. The Manhattan Project: Making the atomic bomb

    SciTech Connect (OSTI)

    Gosling, F.G.

    1994-09-01T23:59:59.000Z

    This article is a short history of the origins and development of the American atomic bomb program during World War II. Beginning with the scientific developments of the pre-war years, the monograph details the role of US government in conducting a secret, nationwide enterprise that took science from the laboratory and into combat with an entirely new type of weapon. The monograph concludes with a discussion of the immediate postwar period, the debate over the Atomic Energy Act of 1946, and the founding of the Atomic Energy Commission.

  8. 1982 bibliography of atomic and molecular processes

    SciTech Connect (OSTI)

    Barnett, C.F.; Crandall, D.H.; Gilbody, H.B.; Gregory, D.C.; Kirkpatrick, M.I.; McDaniel, E.W.; McKnight, R.H.; Meyer, F.W.; Morgan, T.J.; Phaneuf, R.A. (comps.)

    1984-05-01T23:59:59.000Z

    This annotated bibliography includes papers on atomic and molecular processes published during 1982. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory.

  9. Recent emission channeling studies in wide band gap semiconductors

    E-Print Network [OSTI]

    Wahl, Ulrich; Rita, E; Alves, E; Carvalho-Soares, João; De Vries, Bart; Matias, V; Vantomme, A

    2005-01-01T23:59:59.000Z

    We present results of recent emission channeling experiments on the lattice location of implanted Fe and rare earths in wurtzite GaN and ZnO. In both cases the majority of implanted atoms are found on substitutional cation sites. The root mean square displacements from the ideal substitutional Ga and Zn sites are given and the stability of the Fe and rare earth lattice location against thermal annealing is discussed.

  10. Structure and electrical properties of polycrystalline SiGe films grown by molecular beam deposition

    SciTech Connect (OSTI)

    Chistokhin, I. B., E-mail: igor@thermo.isp.nsc.ru; Gutakovskii, A. K.; Deryabin, A. S. [Russian Academy of Sciences, Institute of Semiconductor Physics, Siberian Division (Russian Federation)

    2007-03-15T23:59:59.000Z

    The structural and electrical properties of polycrystalline Si{sub 0.5}Ge{sub 0.5} films 150 nm thick grown by molecular beam deposition at temperatures of 200-550 deg. C on silicon substrates coated with amorphous layers of silicon oxynitride were studied. It is shown that the films consist of a mixture of amorphous and polycrystalline phases. The amorphous phase fraction decreases from {approx}50% in films deposited at 200 deg. C to zero in films grown at 550 deg. C. Subsequent 1-h annealing at a temperature of 550 deg. C results in complete solid-phase crystallization of all films. The electron transport of charge carriers in polycrystalline films occurs by the thermally activated mechanism associated with the energy barrier of {approx}0.2 eV at grain boundaries. Barrier lowering upon additional annealing of SiGe films correlates with an increase in the average grain size.

  11. Mechanism of lateral ordering of InP dots grown on InGaP layers

    SciTech Connect (OSTI)

    Bortoleto, J.R.R.; Gutierrez, H.R.; Cotta, M.A.; Bettini, J. [Instituto de Fisica Gleb Wataghin, DFA, UNICAMP, CP 6165, 13081-970 Campinas-SP (Brazil); Laboratorio Nacional de Luz Sincrotron, CP 6192, 13084-971, Campinas-SP (Brazil)

    2005-07-04T23:59:59.000Z

    The mechanisms leading to the spontaneous formation of a two-dimensional array of InP/InGaP dots grown by chemical-beam epitaxy are discussed. Samples where the InGaP buffer layer was grown at different conditions were characterized by transmission electron microscopy. Our results indicate that a periodic strain field related to lateral two-dimensional compositional modulation in the InGaP buffer layer determines the dot nucleation positions during InP growth. Although the periodic strain field in the InGaP is large enough to align the InP dots, both their shape and optical properties are effectively unaltered. This result shows that compositional modulation can be used as a tool for in situ dot positioning.

  12. Interaction of an aluminum atom with a closed subshell metal atom: Spectroscopic analysis of AlZn

    E-Print Network [OSTI]

    Morse, Michael D.

    Interaction of an aluminum atom with a closed subshell metal atom: Spectroscopic analysis of Al-block main group element, aluminum, and the 3d series of transi- tion metal atoms. Although the bonding in Al

  13. acoustic wave atomization: Topics by E-print Network

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

    of fluid and acoustic computations, hybrid methodologies still Kohlenbach, Ulrich 12 Propagation of atomic matter waves inside an atom wave guide Quantum Physics (arXiv)...

  14. atomic emission spectrometry: Topics by E-print Network

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

    not the direction of the atom's motion. The conclusion is also evident from a simple energy relation: atomic spectral radiation is emitted as an orbiting electron consumes a...

  15. atomic photoabsorption process: Topics by E-print Network

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

    individual sites within atom-trap arrays. Cecilia Muldoon; Lukas Brandt; Jian Dong; Dustin Stuart; Edouard Brainis; Matthew Himsworth; Axel Kuhn 2012-03-21 306 Atomic...

  16. Structure of ?-Alumina: Toward The Atomic Level Understanding...

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

    -Alumina: Toward The Atomic Level Understanding Of Transition Alumina Phases. Structure of -Alumina: Toward The Atomic Level Understanding Of Transition Alumina Phases....

  17. Atomic Energy Commission Explores Peaceful Uses of Nuclear Explosions...

    National Nuclear Security Administration (NNSA)

    Our Jobs Working at NNSA Blog Home About Us Our History NNSA Timeline Atomic Energy Commission Explores Peaceful Uses of ... Atomic Energy Commission Explores Peaceful...

  18. Atomic-Structural Synergy for Catalytic CO Oxidation over Palladium...

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

    Atomic-Structural Synergy for Catalytic CO Oxidation over Palladium-Nickel Nanoalloys. Atomic-Structural Synergy for Catalytic CO Oxidation over Palladium-Nickel Nanoalloys....

  19. atomic carbon nanowires: Topics by E-print Network

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

    Page Topic Index 1 Electron Transport Properties of Atomic Carbon Nanowires between Graphene Electrodes CERN Preprints Summary: Long, stable and free-standing linear atomic...

  20. Isolation, Characterization of an Intermediate in an Oxygen Atom...

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

    Characterization of an Intermediate in an Oxygen Atom-Transfer Reaction, and the Determination of the Bond Isolation, Characterization of an Intermediate in an Oxygen Atom-Transfer...

  1. atom trap trace: Topics by E-print Network

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

    1 An atom trap trace analysis system for measuring krypton contamination in xenon dark matter detectors Physics Websites Summary: An atom trap trace analysis system for measuring...

  2. Materials, Modules, and Systems: An Atoms to Autos Approach to...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Materials, Modules, and Systems: An Atoms to Autos Approach to Automotive Thermoelectric Systems Development Materials, Modules, and Systems: An Atoms to Autos Approach to...

  3. atomic number: Topics by E-print Network

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

    and relative number squeezing in dissociation of spatially inhomogeneous molecular condensates Physics Websites Summary: Atom-atom correlations and relative number squeezing in...

  4. atomic number density: Topics by E-print Network

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

    and relative number squeezing in dissociation of spatially inhomogeneous molecular condensates Quantum Physics (arXiv) Summary: We study atom-atom correlations and relative...

  5. atomic mass number: Topics by E-print Network

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

    and relative number squeezing in dissociation of spatially inhomogeneous molecular condensates Physics Websites Summary: Atom-atom correlations and relative number squeezing in...

  6. atomic number electron: Topics by E-print Network

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

    and relative number squeezing in dissociation of spatially inhomogeneous molecular condensates Physics Websites Summary: Atom-atom correlations and relative number squeezing in...

  7. atom interferometry measurement: Topics by E-print Network

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

    Bose-condensed atoms . Open Access Theses and Dissertations Summary: ??Bose-Einstein condensates are coherent matter waves, produced by cooling gaseous atomic clouds to ultra-low...

  8. atomic wave packets: Topics by E-print Network

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

    Statistics of atomic populations in output coupled wave packets from Bose-Einstein condensates: Four-wave mixing Physics Websites Summary: Statistics of atomic populations in...

  9. atomic number range: Topics by E-print Network

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

    and relative number squeezing in dissociation of spatially inhomogeneous molecular condensates Physics Websites Summary: Atom-atom correlations and relative number squeezing in...

  10. atom interferometry progress: Topics by E-print Network

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

    Bose-condensed atoms . Open Access Theses and Dissertations Summary: ??Bose-Einstein condensates are coherent matter waves, produced by cooling gaseous atomic clouds to ultra-low...

  11. Non-contact atomic-level interfacial force microscopy

    SciTech Connect (OSTI)

    Houston, J.E.; Fleming, J.G.

    1997-02-01T23:59:59.000Z

    The scanning force microscopies (notably the Atomic Force Microscope--AFM), because of their applicability to nearly all materials, are presently the most widely used of the scanning-probe techniques. However, the AFM uses a deflection sensor to measure sample/probe forces which suffers from an inherent mechanical instability that occurs when the rate of change of the force with respect to the interfacial separation becomes equal to the spring constant of the deflecting member. This instability dramatically limits the breadth of applicability of AFM-type techniques to materials problems. In the course of implementing a DOE sponsored basic research program in interfacial adhesion, a self-balancing force sensor concept has been developed and incorporated into an Interfacial Force Microscopy (IFM) system by Sandia scientists. This sensor eliminates the instability problem and greatly enhances the applicability of the scanning force-probe technique to a broader range of materials and materials parameters. The impact of this Sandia development was recognized in 1993 by a Department of Energy award for potential impact on DOE programs and by an R and D 100 award for one of the most important new products of 1994. However, in its present stage of development, the IFM is strictly a research-level tool and a CRADA was initiated in order to bring this sensor technology into wide-spread availability by making it accessible in the form of a commercial instrument. The present report described the goals, approach and results of this CRADA effort.

  12. TEM and HRXRD Analysis of LP MOVPE Grown InGaP/GaAs epilayers

    SciTech Connect (OSTI)

    Pelosi, Claudio; Bosi, Matteo; Attolini, Giovanni; Germini, Fabrizio; Frigeri, Cesare [CNR-IMEM Institute, Parco Area delle Scienze 37a, Loc Fontanini 43010 Parma (Italy); Prutskij, Tatiana [Instituto de Ciencias, BUAP, Privada 17 Norte, no. 3417, colSanMiguel Hueyotlipan, 72050 Puebla, Pue. (Mexico)

    2007-04-10T23:59:59.000Z

    The diffusion phenomena at interfaces between GaAs/InGaP layers grown by low pressure MOVPE have been studied by dark field (DF) transmission Electron Microscopy (TEM) and High resolution X-ray Diffractometry (HRXRD). By comparing the results of the two techniques a mismatched layer containing P or P and In has been evidenced. The causes of this behavior are briefly discussed.

  13. Current crowding in GaInN / GaN LEDs grown on insulating substrates X. Guo, E. F. Schubert and J. Jahns

    E-Print Network [OSTI]

    Jahns, Jürgen

    Current crowding in GaInN / GaN LEDs grown on insulating substrates X. Guo, E. F. Schubert and J spreading in a mesa-structure GaN-based LED grown on an insulating or semi-insulating substrate. (b. Jahns Current crowding in mesa-structure GaInN/GaN light-emitting diodes (LEDs) grown on insulating

  14. Transmission Electron Microscopy Study of Nonpolar a-Plane GaN Grown by Pendeo-Epitaxy on (112_0) 4H-SiC

    E-Print Network [OSTI]

    Zakharov, D.N.; Liliental-Weber, Z.; Wagner, B.; Reitmeier, Z.J.; Preble, E.A.; Davis, R.F.

    2008-01-01T23:59:59.000Z

    pendeo-epitaxial GaN layer grown on (1120) 4H-SiC substrate.a-plane GaN layers grown on (1120) 4H-SiC substrate with AlNGaN layers grown by heteroepitaxial methods on different substrates

  15. Physicochemical and electrical characterizations of atomic layer deposition grown HfO2 on TiN and Pt for metal-insulator-metal application

    E-Print Network [OSTI]

    Boyer, Edmond

    for the physicochemical characterization in order to study the junction interface and determine the oxide thickness reflectance. Electrical characteristics of the structures with different oxide thicknesses and an evaporated insulating materials with a higher dielectric constant.1 These materials shall lead to a high capacitance

  16. Measuring Meaning on the World-Wide Web

    E-Print Network [OSTI]

    Aerts, Diederik

    2010-01-01T23:59:59.000Z

    We introduce the notion of the 'meaning bound' of a word with respect to another word by making use of the World-Wide Web as a conceptual environment for meaning. The meaning of a word with respect to another word is established by multiplying the product of the number of webpages containing both words by the total number of webpages of the World-Wide Web, and dividing the result by the product of the number of webpages for each of the single words. We calculate the meaning bounds for several words and analyze different aspects of these by looking at specific examples.

  17. Diffusion of cations in chromia layers grown on iron-base alloys

    SciTech Connect (OSTI)

    Lobnig, R.E.; Hennesen, K.; Grabke, H.J. (Max-Planck Inst. fur Eisenforschung, Duesseldorf (West Germany)); Schmidt, H.P.

    1992-02-01T23:59:59.000Z

    Diffusion of the cations Cr, Fe, Mn, and Ni in Cr{sub 2}O{sub 3} has been investigated at 1,173 K. The diffusion measurements were performed on chromia layers grown on the model alloys Fe-20Cr and Fe-20Cr-12Ni in order to consider effects of small amounts of dissolved alien cations in Cr{sub 2}O{sub 3}. The samples were diffusion annealed in H{sub 2}-H{sub 2}O at an oxygen partial pressure close to the Cr{sub 2}O{sub 3}/Cr equilibrium. For all tracers the lattice-diffusion coefficients are 3-5 orders of magnitude smaller than the grain-boundary diffusion coefficients. The lattice diffusivity of Mn is about two orders of magnitude greater than the other lattice-diffusion coefficients, especially in Cr{sub 2}O{sub 3} grown on Fe-20Cr-12Ni. The values of the diffusion coefficients for Cr, Fe, and Ni are in the same range. Diffusion of the tracers in Cr{sub 2}O{sub 3} grown on different alloys did not show significant differences with the exception of Mn.

  18. Adsorption of Atoms and Molecules Physisorption

    E-Print Network [OSTI]

    Glashausser, Charles

    Adsorption of Atoms and Molecules Physisorption Chemisorption Surface Bonding Kinetics of Adsorption/Diffusion/Desorption (Scattering Dynamics) #12;Outcomes of Collision Process Rebound (elastically or inelastically) Elastic Scattering Inelastic Scattering Accomodation (thermalizing) Adsorption E V(r) r

  19. Atomic physics: An almost lightless laser

    E-Print Network [OSTI]

    Vuletic, Vladan

    Lasers are often described in terms of a light field circulating in an optical resonator system. Now a laser has been demonstrated in which the field resides primarily in the atomic medium that is used to generate the light.

  20. FREQUENCY DEPENDENT MULTIPOLE POLARIZABILITIES OF ATOMIC SYSTEMS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1259 FREQUENCY DEPENDENT MULTIPOLE POLARIZABILITIES OF ATOMIC SYSTEMS S. I. EASA and G. C. SHUKLA et d'helium. Abstract. 2014 A variational calculation for frequency dependent multipole 1978, Classification Physics Abstracts 31.10 The calculation of multipole polarizabilities

  1. Electronic transport in atomically thin layered materials

    E-Print Network [OSTI]

    Baugher, Britton William Herbert

    2014-01-01T23:59:59.000Z

    Electronic transport in atomically thin layered materials has been a burgeoning field of study since the discovery of isolated single layer graphene in 2004. Graphene, a semi-metal, has a unique gapless Dirac-like band ...

  2. Accurate capacitive metrology for atomic force microscopy

    E-Print Network [OSTI]

    Mazzeo, Aaron D. (Aaron David), 1979-

    2005-01-01T23:59:59.000Z

    This thesis presents accurate capacitive sensing metrology designed for a prototype atomic force microscope (AFM) originally developed in the MIT Precision Motion Control Lab. The capacitive measurements use a set of ...

  3. Quantum Structures of the Hydrogen Atom

    E-Print Network [OSTI]

    J. Jeknic-Dugic; M. Dugic; A. Francom; M. Arsenijevic

    2014-05-28T23:59:59.000Z

    Modern quantum theory introduces quantum structures (decompositions into subsystems) as a new discourse that is not fully comparable with the classical-physics counterpart. To this end, so-called Entanglement Relativity appears as a corollary of the universally valid quantum mechanics that can provide for a deeper and more elaborate description of the composite quantum systems. In this paper we employ this new concept to describe the hydrogen atom. We offer a consistent picture of the hydrogen atom as an open quantum system that naturally answers the following important questions: (a) how do the so called "quantum jumps" in atomic excitation and de-excitation occur? and (b) why does the classically and seemingly artificial "center-of-mass + relative degrees of freedom" structure appear as the primarily operable form in most of the experimental reality of atoms?

  4. United Nations Atomic Energy Commission stalls out

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

    commission would be short-lived and would not result in the desired control of atomic energy. In the wake of the disappointing results of the Moscow meeting, the United States...

  5. Moving closer to the Atomic Energy Commission

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

    in some way. On October 3, 1945 the president addressed Congress on the subject of atomic energy. Here he first mentioned the need for international agreements. Attempts were made...

  6. Quantum micro-mechanics with ultracold atoms

    E-Print Network [OSTI]

    Thierry Botter; Daniel Brooks; Subhadeep Gupta; Zhao-Yuan Ma; Kevin L. Moore; Kater W. Murch; Tom P. Purdy; Dan M. Stamper-Kurn

    2008-10-21T23:59:59.000Z

    In many experiments isolated atoms and ions have been inserted into high-finesse optical resonators for the study of fundamental quantum optics and quantum information. Here, we introduce another application of such a system, as the realization of cavity optomechanics where the collective motion of an atomic ensemble serves the role of a moveable optical element in an optical resonator. Compared with other optomechanical systems, such as those incorporating nanofabricated cantilevers or the large cavity mirrors of gravitational observatories, our cold-atom realization offers direct access to the quantum regime. We describe experimental investigations of optomechanical effects, such as the bistability of collective atomic motion and the first quantification of measurement backaction for a macroscopic object, and discuss future directions for this nascent field.

  7. Remote-State Prparation eines einzelnen Atoms

    E-Print Network [OSTI]

    Weinfurter, Harald

    Remote-State Präparation eines einzelnen Atoms Diplomarbeit am Department für Physik der Ludwig . . . . . . . . . . . . . . . . . . . . . 8 1.3.3 Remote-State-Präparation . . . . . . . . . . . . . . . . . . . . . 11 1.3.4 Zusammenfassung . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3 Remote-State-Präparation 31 3.1 Einleitung

  8. Electrical Analogs of Atomic Radiative Decay Processes

    E-Print Network [OSTI]

    Fontana, Peter R.; Srivastava, Rajendra P.

    1977-03-01T23:59:59.000Z

    Simple electrical circuits are analyzed, and the results show that for high frequencies they have frequency and time responses identical to the spontaneous radiative decays of atoms. As an illustration of the analogy a two-circuit electrical system...

  9. Atomic vapor spectroscopy in integrated photonic structures

    E-Print Network [OSTI]

    Ritter, Ralf; Pernice, Wolfram; Kübler, Harald; Pfau, Tilman; Löw, Robert

    2015-01-01T23:59:59.000Z

    We investigate an integrated optical chip immersed in atomic vapor providing several waveguide geometries for spectroscopy applications. The narrow-band transmission through a silicon nitride waveguide and interferometer is altered when the guided light is coupled to a vapor of rubidium atoms via the evanescent tail of the waveguide mode. We use grating couplers to couple between the waveguide mode and the radiating wave, which allow for addressing arbitrary coupling positions on the chip surface. The evanescent atom-light interaction can be numerically simulated and shows excellent agreement with our experimental data. This work demonstrates a next step towards miniaturization and integration of alkali atom spectroscopy and provides a platform for further fundamental studies of complex waveguide structures.

  10. Hydrogen atom in rotationally invariant noncommutative space

    E-Print Network [OSTI]

    Kh. P. Gnatenko; V. M. Tkachuk

    2014-11-03T23:59:59.000Z

    We consider the noncommutative algebra which is rotationally invariant. The hydrogen atom is studied in a rotationally invariant noncommutative space. We find the corrections to the energy levels of the hydrogen atom up to the second order in the parameter of noncommutativity. The upper bound of the parameter of noncommutativity is estimated on the basis of the experimental results for 1s-2s transition frequency.

  11. Atomic resolution images of graphite in air

    SciTech Connect (OSTI)

    Grigg, D.A.; Shedd, G.M.; Griffis, D.; Russell, P.E.

    1988-12-01T23:59:59.000Z

    One sample used for proof of operation for atomic resolution in STM is highly oriented pyrolytic graphite (HOPG). This sample has been imaged with many different STM`s obtaining similar results. Atomic resolution images of HOPG have now been obtained using an STM designed and built at the Precision Engineering Center. This paper discusses the theoretical predictions and experimental results obtained in imaging of HOPG.

  12. Controlling the Ratchet Effect for Cold Atoms

    E-Print Network [OSTI]

    Anatole Kenfack; Jiangbin Gong; Arjendu K. Pattanayak

    2007-11-27T23:59:59.000Z

    Low-order quantum resonances manifested by directed currents have been realized with cold atoms. Here we show that by increasing the strength of an experimentally achievable delta-kicking ratchet potential, quantum resonances of a very high order may naturally emerge and can induce larger ratchet currents than low-order resonances, with the underlying classical limit being fully chaotic. The results offer a means of controlling quantum transport of cold atoms.

  13. ac-driven atomic quantum motor

    E-Print Network [OSTI]

    A. V. Ponomarev; S. Denisov; P. Hanggi

    2009-06-09T23:59:59.000Z

    We invent an ac-driven quantum motor consisting of two different, interacting ultracold atoms placed into a ring-shaped optical lattice and submerged in a pulsating magnetic field. While the first atom carries a current, the second one serves as a quantum starter. For fixed zero-momentum initial conditions the asymptotic carrier velocity converges to a unique non-zero value. We also demonstrate that this quantum motor performs work against a constant load.

  14. From Lattice Gauge Theories to Hydrogen Atoms

    E-Print Network [OSTI]

    Manu Mathur; T. P. Sreeraj

    2014-10-13T23:59:59.000Z

    Using canonical transformations we obtain a complete and most economical realization of the loop or physical Hilbert space of pure $SU(2)_{2+1}$ lattice gauge theory in terms of Wigner coupled Hilbert spaces of hydrogen atoms. One hydrogen atom is assigned to every plaquette of the lattice. The SU(2) gauge theory loop basis states over a plaquette are the bound energy eigenstates $|n l m>$ of the corresponding hydrogen atom. The Wigner couplings of these hydrogen atom energy eigenstates on different plaquettes provide a complete SU(2) gauge theory loop basis on the entire lattice. The loop basis is invariant under simultaneous rotations of all hydrogen atoms. The dual description of this basis diagonalizes all Wilson loop operators and is given in terms of hyperspherical harmonics on the SU(2) group manifold $S^3$. The SU(2) loop dynamics is governed by a "SU(2) spin Hamiltonian" without any gauge fields. The relevance of the hydrogen atom basis and its dynamical symmetry group SO(4,2) in SU(2) loop dynamics in weak coupling continuum limit ($g^2\\rightarrow 0$) is emphasized.

  15. Excess optical quantum noise in atomic sensors

    E-Print Network [OSTI]

    Irina Novikova; Eugeniy E. Mikhailov; Yanhong Xiao

    2014-10-14T23:59:59.000Z

    Enhanced nonlinear optical response of a coherent atomic medium is the basis for many atomic sensors, and their performance is ultimately limited by the quantum fluctuations of the optical read-out. Here we demonstrate that off-resonant interactions can significantly modify the quantum noise of the optical field, even when their effect on the mean signal is negligible. We illustrate this concept by using an atomic magnetometer based on the nonlinear Faraday effect: the rotation of the light polarization is mainly determined by the resonant light-induced spin alignment, which alone does not change the photon statistics of the optical probe. Yet, we found that the minimum noise of output polarization rotation measurements is above the expected shot noise limit. This excess quantum noise is due to off-resonant coupling and grows with atomic density. We also show that the detection scheme can be modified to reduce the measured quantum noise (even below the shot-noise limit) but only at the expense of the reduced rotational sensitivity. These results show the existence of previously unnoticed factors in fundamental limitations in atomic magnetometry and could have impacts in many other atom-light based precision measurements.

  16. Atoms 2014, 2, 157-177; doi:10.3390/atoms2020157 OPEN ACCESS

    E-Print Network [OSTI]

    Atoms 2014, 2, 157-177; doi:10.3390/atoms2020157 OPEN ACCESS atomsISSN 2218-2004 www]: = ne2 ¯h2 - dt1 t1 - dt2E(t1)·E(t2)ei (t1-t2) (3) where E(t1)·E(t2) = 2 3 0 vf(v)dv max 0 dE(t1

  17. Development of a World Wide Web based quiz management system

    E-Print Network [OSTI]

    Taylor, Shannon Carol

    1997-01-01T23:59:59.000Z

    over the World Wide Web (WWW) using a WWW browser that is frame-capable. This system would allow instructors to assign quizzes to be taken outside of lecture time on the Internet, which would allow them more lecture time. This system also allows users...

  18. ORIGINAL RESEARCH Systematic family-wide analysis of sodium bicarbonate

    E-Print Network [OSTI]

    Hall, Randy A

    ORIGINAL RESEARCH Systematic family-wide analysis of sodium bicarbonate cotransporter NBCn1/SLC4A7/NBCn1 pulled down syntrophin c2 and con- versely GST/syntrophin c2 pulled down NBCn1. Moreover normally moves Na+ and HCO3 Ã? into cells and protects intracel- lular pH (pHi) from falling below normal

  19. aid policy wide: Topics by E-print Network

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

    aid policy wide First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Aid, Policy and Peace CiteSeer Summary:...

  20. **NEW UNIVERSITY-WIDE MINOR ** Minor in Sustainable Energy

    E-Print Network [OSTI]

    Goldberg, Bennett

    **NEW UNIVERSITY-WIDE MINOR ** Minor in Sustainable Energy Energy is central. The Minor in Sustainable Energy allows a student in any four-year undergraduate School or College perspectives, as taught by faculty in those areas. The minor in Sustainable Energy is a collaborative effort

  1. Genome-Wide In Silico Identification of Transcriptional Regulators Controlling

    E-Print Network [OSTI]

    Shamir, Ron

    Genome-Wide In Silico Identification of Transcriptional Regulators Controlling the Cell Cycle networks that control gene transcription is one of the greatest challenges of functional genomics. Using human genomic sequences, models for binding sites of known transcription factors, and gene expression

  2. Supporting Generic Cost Models for Wide-Area Stream Processing

    E-Print Network [OSTI]

    Cetintemel, Ugur

    Supporting Generic Cost Models for Wide-Area Stream Processing Olga Papaemmanouil #1 , Ugur C¸ etintemel 2 , John Jannotti 2 # Deparment of Computer Science, Brandeis University, Waltham, MA, USA 1 olga and increased availability of receptors that report physical or software events has led to the emergence

  3. Data Mining Middleware for Wide Area High Performance Networks

    E-Print Network [OSTI]

    Grossman, Robert

    1 Data Mining Middleware for Wide Area High Performance Networks Robert L. Grossman*, Yunhong Gu, David Hanley, and Michal Sabala National Center for Data Mining, University of Illinois at Chicago, USA astronomical data from the Sloan Digital Sky Survey (SDSS) and the other involves computing histograms from

  4. Photocell utilizing a wide-bandgap semiconductor material

    DOE Patents [OSTI]

    Carlson, David E. (Yardley, PA); Williams, Brown F. (Princeton, NJ)

    1984-06-05T23:59:59.000Z

    A photocell comprises a p-i-n amorphous silicon structure having a wide bandgap layer adjacent to either the p-type or n-type layer. This structure reduces the absorption of light entering the photocell and the back-diffusion of minority carriers.

  5. Materials Technology for Energy Efficiency: Wide Bandgap Nanophotonics Lab

    E-Print Network [OSTI]

    University of Technology, Sydney

    28/3/2013 Materials Technology for Energy Efficiency: Wide Bandgap Nanophotonics Lab Honours such as low power lasers, molecular sensors and high efficiency light emitters. Several projects are currently of Technology Sydney is one of the leading technological universities in Australia and located in the heart

  6. STRUCTURE PREDICTION CASP AND OTHER COMMUNITY-WIDE

    E-Print Network [OSTI]

    Bourne, Philip E.

    Section VI STRUCTURE PREDICTION #12;#12;28 CASP AND OTHER COMMUNITY-WIDE ASSESSMENTS TO ADVANCE THE FIELD OF STRUCTURE PREDICTION Jenny Gu and Philip E. Bourne A MEASURE FOR SUCCESS In the early 1990s to the biological community and to measure the progress in this developing field of structure prediction. In part

  7. Atoms for peace and war, 1953-1961: Eisenhower and the Atomic Energy Commission

    SciTech Connect (OSTI)

    Hewlett, Richard G.; Holl, Jack M.

    1989-12-01T23:59:59.000Z

    This third volume in the official history of the U.S. Atomic Energy Commission covers the years of the Eisenhower Administration.

  8. Traffic flow wide-area surveillance system definition

    SciTech Connect (OSTI)

    Allgood, G.O.; Ferrell, R.K.; Kercel, S.W.; Abston, R.A.; Carnal, C.L. [Oak Ridge National Lab., TN (United States); Moynihan, P.I. [Jet Propulsion Lab., Pasadena, CA (United States)

    1994-11-01T23:59:59.000Z

    Traffic Flow Wide-Area Surveillance (TFWAS) is a system for assessing the state of traffic flow over a wide area for enhanced traffic control and improved traffic management and planning. The primary purpose of a TFWAS system is to provide a detailed traffic flow description and context description to sophisticated traffic management and control systems being developed or envisioned for the future. A successful TFWAS system must possess the attributes of safety, reconfigurability, reliability, and expandability. The primary safety premise of TFWAS is to ensure that no action or failure of the TFWAS system or its components can result in risk of injury to humans. A wide variety of communication techniques is available for use with TFWAS systems. These communication techniques can be broken down into two categories, landlines and wireless. Currently used and possible future traffic sensing technologies have been examined. Important criteria for selecting TFWAS sensors include sensor capabilities, costs, operational constraints, sensor compatibility with the infrastructure, and extent. TFWAS is a concept that can take advantage of the strengths of different traffic sensing technologies, can readily adapt to newly developed technologies, and can grow with the development of new traffic control strategies. By developing innovative algorithms that will take information from a variety of sensor types and develop descriptions of traffic flows over a wide area, a more comprehensive understanding of the traffic state can be provided to the control system to perform the most reasonable control actions over the entire wide area. The capability of characterizing the state of traffic over an entire region should revolutionize developments in traffic control strategies.

  9. Synthesis of multiferroic Er-Fe-O thin films by atomic layer and chemical vapor deposition

    SciTech Connect (OSTI)

    Mantovan, R., E-mail: roberto.mantovan@mdm.imm.cnr.it; Vangelista, S.; Wiemer, C.; Lamperti, A.; Tallarida, G. [Laboratorio MDM IMM-CNR, I-20864 Agrate Brianza (MB) (Italy); Chikoidze, E.; Dumont, Y. [GEMaC, Université de Versailles St. Quentin en Yvelines-CNRS, Versailles (France); Fanciulli, M. [Laboratorio MDM IMM-CNR, I-20864 Agrate Brianza (MB) (Italy); Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Milano (Italy)

    2014-05-07T23:59:59.000Z

    R-Fe-O (R?=?rare earth) compounds have recently attracted high interest as potential new multiferroic materials. Here, we report a method based on the solid-state reaction between Er{sub 2}O{sub 3} and Fe layers, respectively grown by atomic layer deposition and chemical vapor deposition, to synthesize Er-Fe-O thin films. The reaction is induced by thermal annealing and evolution of the formed phases is followed by in situ grazing incidence X-ray diffraction. Dominant ErFeO{sub 3} and ErFe{sub 2}O{sub 4} phases develop following subsequent thermal annealing processes at 850?°C in air and N{sub 2}. Structural, chemical, and morphological characterization of the layers are conducted through X-ray diffraction and reflectivity, time-of-flight secondary ion-mass spectrometry, and atomic force microscopy. Magnetic properties are evaluated by magnetic force microscopy, conversion electron Mössbauer spectroscopy, and vibrating sample magnetometer, being consistent with the presence of the phases identified by X-ray diffraction. Our results constitute a first step toward the use of cost-effective chemical methods for the synthesis of this class of multiferroic thin films.

  10. Preparation and atomic structure of reconstructed (0001) InGaN surfaces

    SciTech Connect (OSTI)

    Friedrich, C.; Biermann, A.; Kneissl, M.; Vogt, P. [Institut fuer Festkoerperphysik EW6-1, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Hoffmann, V. [Ferdinand-Braun-Institut, Leibniz-Institut fuer Hoechstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin (Germany); Esser, N. [Institut fuer Festkoerperphysik EW6-1, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Leibniz-Institut fuer Analytische Wissenschaften - ISAS e.V., Albert-Einstein-Str. 9, 12489 Berlin (Germany)

    2012-08-01T23:59:59.000Z

    The preparation and surface structure of high quality group-III-polar (0001) InGaN layers grown by metal-organic vapor phase epitaxy have been investigated. In order to obtain a clean and well-ordered surface we studied the preparation by annealing at various temperatures under ultra high vacuum and nitrogen-rich conditions in nitrogen-plasma. We show that different InGaN surface reconstructions such as (1 Multiplication-Sign 1), (1 + 1/6), (2 Multiplication-Sign 2), and ({radical}(3) Multiplication-Sign {radical}(3))R30 Degree-Sign can be obtained as observed by low energy electron diffraction. Dependent on the annealing temperature and nitrogen supply these surfaces exhibit significant differences in stoichiometry and morphology as determined by Auger electron spectroscopy and atomic force microscopy measurements. The (1 Multiplication-Sign 1), (2 Multiplication-Sign 2), and ({radical}(3) Multiplication-Sign {radical}(3))R30 Degree-Sign superstructures are terminated by single group-III-adatoms, whereas the (1 + 1/6) exhibits a incommensurate overlayer of group-III-atoms. We show that the (2 Multiplication-Sign 2) and ({radical}(3) Multiplication-Sign {radical}(3))R30 Degree-Sign an In depletion in the first group-III layer and In or Ga adatoms in ontop position. Strain-relaxation is suggested to explain this structure formation.

  11. Spontaneous formation of highly regular superlattice structure in InGaN epilayers grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Wu, Z. H. [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Graduate School of Engineering, Akasaki Research Center, Nagoya University, Chikusa-ku, Nagoya 464-8603 (Japan); Kawai, Y.; Honda, Y.; Yamaguchi, M.; Amano, H. [Graduate School of Engineering, Akasaki Research Center, Nagoya University, Chikusa-ku, Nagoya 464-8603 (Japan); Fang, Y.-Y.; Chen, C. Q. [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Kondo, H.; Hori, M. [Graduate School of Engineering, Plasma Nanotechnology Research Center, Nagoya University, Chikusa-ku, Nagoya 464-8603 (Japan)

    2011-04-04T23:59:59.000Z

    In this letter, we have investigated the structural properties of thick InGaN layers grown on GaN by plasma-assisted molecular beam epitaxy, using two growth rates of 1.0 and 3.6 A/s. A highly regular superlattice (SL) structure is found to be spontaneously formed in the film grown at 3.6 A/s but not in the film grown at 1.0 A/s. The faster grown film also exhibits superior structural quality, which could be due to the surface roughness suppression caused by kinetic limitation, and the inhibition of the Frank-Read dislocation generation mechanism within the spontaneously formed SL structure.

  12. Spectral hole burning and optically detected nuclear quadrupole resonance in flux-grown stoichiometric europium vanadate crystals

    E-Print Network [OSTI]

    Hansen, Peter

    -grown stoichiometric europium vanadate crystals P. C. Hansen, M. J. M. Leask, and B. M. Wanklyn Clarendon Laboratory prompted first a parallel study of the isomor- phous compound europium arsenate, EuAsO4,2 that showed very

  13. Structural anisotropic properties of a-plane GaN epilayers grown on r-plane sapphire by molecular beam epitaxy

    SciTech Connect (OSTI)

    Lotsari, A.; Kehagias, Th.; Katsikini, M.; Arvanitidis, J.; Ves, S.; Komninou, Ph.; Dimitrakopulos, G. P., E-mail: gdim@auth.gr [Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Tsiakatouras, G.; Tsagaraki, K.; Georgakilas, A. [Department of Physics, Microelectronics Research Group, University of Crete, P.O. Box 2208, GR 71003, Greece and IESL, FORTH, P.O. Box 1385, GR71110 Heraklion (Greece); Christofilos, D. [Physics Division, School of Technology, Aristotle University of Thessaloniki, GR54124 Thessaloniki (Greece)

    2014-06-07T23:59:59.000Z

    Heteroepitaxial non-polar III-Nitride layers may exhibit extensive anisotropy in the surface morphology and the epilayer microstructure along distinct in-plane directions. The structural anisotropy, evidenced by the “M”-shape dependence of the (112{sup ¯}0) x-ray rocking curve widths on the beam azimuth angle, was studied by combining transmission electron microscopy observations, Raman spectroscopy, high resolution x-ray diffraction, and atomic force microscopy in a-plane GaN epilayers grown on r-plane sapphire substrates by plasma-assisted molecular beam epitaxy (PAMBE). The structural anisotropic behavior was attributed quantitatively to the high dislocation densities, particularly the Frank-Shockley partial dislocations that delimit the I{sub 1} intrinsic basal stacking faults, and to the concomitant plastic strain relaxation. On the other hand, isotropic samples exhibited lower dislocation densities and a biaxial residual stress state. For PAMBE growth, the anisotropy was correlated to N-rich (or Ga-poor) conditions on the surface during growth, that result in formation of asymmetric a-plane GaN grains elongated along the c-axis. Such conditions enhance the anisotropy of gallium diffusion on the surface and reduce the GaN nucleation rate.

  14. Growth of Si{sub 0.75}Ge{sub 0.25} alloy layers grown on Si(001) substrates using step-graded short-period (Si{sub m}/Ge{sub n}){sub N} superlattices

    SciTech Connect (OSTI)

    Rahman, M. M.; Matada, H.; Tambo, T.; Tatsuyama, C.

    2001-07-01T23:59:59.000Z

    Short-period (Si{sub m}/Ge{sub n}){sub N} superlattices (SSLs) are grown step by step on a Si(001) substrates by solid source molecular beam epitaxy. Using the step-graded SSLs as buffer layers, 2000 Aa uniform Si{sub 0.75}Ge{sub 0.25} alloy layers are grown on the same substrates. The growth temperature of the SSLs and uniform layers is 500{degree}C. In the SSLs layers, m and n are the number of monolayers of Si and Ge, respectively. N is the period of (Si{sub m}/Ge{sub n}) bilayers. The samples grown are characterized by x-ray diffraction, atomic force microscopy (AFM), and transmission electron microscopy (TEM) as a function of the step number of SSL layers. The SSLs show very smooth surfaces [the root-mean-square (rms) surface roughness is between 7 and 12 Aa]. A dramatic decrease in roughness is observed in the uniform Si{sub 0.75}Ge{sub 0.25} alloy layers, when even a one-step SSL is used as a buffer layer. A noticeable increase in rms roughness is seen in both SSL and alloy layers when the number of Ge monolayers is changed from one to two. AFM observation shows that the rms surface roughness behavior of the SSLs is reflected to their corresponding top alloy layers. The residual strains in alloy layers are considerably lower, with a maximum relaxation rate of about 80% for the sample with a seven-step SSL buffer. Cross-sectional TEM images show that strained SSL buffer layers effectively deflect threading dislocations in the substrate or confine the dislocations in the SSL buffer layers. {copyright} 2001 American Institute of Physics.

  15. Effects of laser energy fluence on the onset and growth of the Rayleigh-Taylor instabilities and its influence on the topography of the Fe thin film grown in pulsed laser deposition facility

    SciTech Connect (OSTI)

    Mahmood, S. [National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore); Department of Physics, University of Karachi, Karachi 75270 (Pakistan); Rawat, R. S.; Wang, Y.; Lee, S.; Tan, T. L.; Springham, S. V.; Lee, P. [National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore); Zakaullah, M. [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan)

    2012-10-15T23:59:59.000Z

    The effect of laser energy fluence on the onset and growth of Rayleigh-Taylor (RT) instabilities in laser induced Fe plasma is investigated using time-resolved fast gated imaging. The snow plow and shock wave models are fitted to the experimental results and used to estimate the ablation parameters and the density of gas atoms that interact with the ablated species. It is observed that RT instability develops during the interface deceleration stage and grows for a considerable time for higher laser energy fluence. The effects of RT instabilities formation on the surface topography of the Fe thin films grown in pulsed laser deposition system are investigated (i) using different laser energy fluences for the same wavelength of laser radiation and (ii) using different laser wavelengths keeping the energy fluence fixed. It is concluded that the deposition achieved under turbulent condition leads to less smooth deposition surfaces with bigger sized particle agglomerates or network.

  16. A water quality assessment of the import of turfgrass sod grown with composted dairy manure into a suburban watershed

    E-Print Network [OSTI]

    Richards, Chad Edward

    2005-02-17T23:59:59.000Z

    A WATER QUALITY ASSESSMENT OF THE IMPORT OF TURFGRASS SOD GROWN WITH COMPOSTED DAIRY MANURE INTO A SUBURBAN WATERSHED A Thesis by CHAD EDWARD RICHARDS Submitted to the Office of Graduate Studies of Texas A... OF TURFGRASS SOD GROWN WITH COMPOSTED DAIRY MANURE INTO A SUBURBAN WATERSHED A Thesis by CHAD EDWARD RICHARDS Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE...

  17. Low gap amorphous GaN1-xAsx alloys grown on glass substrate K. M. Yu,1,a

    E-Print Network [OSTI]

    Wu, Junqiao

    Low gap amorphous GaN1-xAsx alloys grown on glass substrate K. M. Yu,1,a S. V. Novikov,2 R September 2010 Amorphous GaN1-xAsx layers with As content in the range of x=0.1 to 0.6 were grown defined optical absorption edges. The measured band gap values for the crystalline and amorphous GaN1-x

  18. 29Counting Atoms in a Molecule The complex molecule Propanal

    E-Print Network [OSTI]

    29Counting Atoms in a Molecule The complex molecule Propanal was discovered in a dense interstellar is the ratio of carbon atoms to hydrogen atoms in propanal? Problem 4 - If the mass of a hydrogen atom of a propanal molecule in AMUs? Problem 5 - What is the complete chemical formula for propanal? C3 H __ O

  19. ATOMIC PHYSICS DMITRY BUDKER | DEREK F. KIMBALL | DAVID P. DEMILLE

    E-Print Network [OSTI]

    Pines, Alexander

    symmetries, atomic magnetometers and frequency comb metrology with ultra-short laser pulses. Dmitry Budker

  20. Isolating and moving single atoms using silicon nanocrystals

    DOE Patents [OSTI]

    Carroll, Malcolm S. (Albuquerque, NM)

    2010-09-07T23:59:59.000Z

    A method is disclosed for isolating single atoms of an atomic species of interest by locating the atoms within silicon nanocrystals. This can be done by implanting, on the average, a single atom of the atomic species of interest into each nanocrystal, and then measuring an electrical charge distribution on the nanocrystals with scanning capacitance microscopy (SCM) or electrostatic force microscopy (EFM) to identify and select those nanocrystals having exactly one atom of the atomic species of interest therein. The nanocrystals with the single atom of the atomic species of interest therein can be sorted and moved using an atomic force microscope (AFM) tip. The method is useful for forming nanoscale electronic and optical devices including quantum computers and single-photon light sources.

  1. Atomic-level imaging, processing and characterization of semiconductor surfaces

    DOE Patents [OSTI]

    Kazmerski, L.L.

    1995-08-22T23:59:59.000Z

    A method for selecting and removing single specific atoms from a solid material surface uses photon biasing to break down bonds that hold the selected atom in the lattice and to reduce barrier effects that hold the atom from transferring to a probe. The photon bias is preferably light or other electromagnetic radiation with a wavelength and frequency that approximately matches the wave function of the target atom species to be removed to induce high energy, selective thermionic-like vibration. An electric field potential is then applied between the probe and the surface of the solid material to pull the atom out of the lattice and to transfer the atom to the probe. Different extrinsic atoms can be installed in the lattice sites that are vacated by the removed atoms by using a photon bias that resonates the extrinsic atom species, reversing polarity of the electric field, and blowing gas comprising the extrinsic atoms through a hollow catheter probe. 8 figs.

  2. Atomic-level imaging, processing and characterization of semiconductor surfaces

    DOE Patents [OSTI]

    Kazmerski, Lawrence L. (Lakewood, CO)

    1995-01-01T23:59:59.000Z

    A method for selecting and removing single specific atoms from a solid material surface uses photon biasing to break down bonds that hold the selected atom in the lattice and to reduce barrier effects that hold the atom from transferring to a probe. The photon bias is preferably light or other electromagnetic radiation with a wavelength and frequency that approximately matches the wave function of the target atom species to be removed to induce high energy, selective thermionic-like vibration. An electric field potential is then applied between the probe and the surface of the solid material to pull the atom out of the lattice and to transfer the atom to the probe. Different extrinsic atoms can be installed in the lattice sites that are vacated by the removed atoms by using a photon bias that resonates the extrinsic atom species, reversing polarity of the electric field, and blowing gas comprising the extrinsic atoms through a hollow catheter probe.

  3. Chapter 44. Cooling and Trapping Neutral Atoms Cooling and Trapping Neutral Atoms

    E-Print Network [OSTI]

    transition. This year, we made progress in developing novel detection and cooling techniques. 1. SpinChapter 44. Cooling and Trapping Neutral Atoms 44-1 Cooling and Trapping Neutral Atoms RLE Groups in optical lattices. Additional cooling methods will be needed to reach this very interesting temperature

  4. Hydrogen atom in de Sitter spaces

    E-Print Network [OSTI]

    O. V. Veko; K. V. Kazmerchuk; E. M. Ovsiyuk; V. M. Red'kov; A. M. Ishkhanyan

    2014-12-28T23:59:59.000Z

    The hydrogen atom theory is developed for the de Sitter and anti de Sitter spaces on the basis of the Klein-Gordon-Fock wave equation in static coordinates. In both models, after separation of the variables, the problem is reduced to the general Heun equation, a second order linear differential equation having four regular singular points. A qualitative examination shows that the energy spectrum for the hydrogen atom in the de Sitter space should be quasi-stationary, and the atom should be unstable. We derive an approximate expression for energy levels within the quasi-classical approach and estimate the probability of decay of the atom. A similar analysis shows that in the anti de Sitter model the hydrogen atom should be stable in the quantum-mechanical sense. Using the quasi-classical approach, we derive approximate formulas for energy levels for this case as well. Finally, we present the extension to the case of a spin 1/2 particle for both de Sitter models. This extension leads to complicated differential equations with 8 singular points.

  5. Method and apparatus for atomic imaging

    DOE Patents [OSTI]

    Saldin, Dilano K. (Milwaukee, WI); de Andres Rodriquez, Pedro L. (Madrid, ES)

    1993-01-01T23:59:59.000Z

    A method and apparatus for three dimensional imaging of the atomic environment of disordered adsorbate atoms are disclosed. The method includes detecting and measuring the intensity of a diffuse low energy electron diffraction pattern formed by directing a beam of low energy electrons against the surface of a crystal. Data corresponding to reconstructed amplitudes of a wave form is generated by operating on the intensity data. The data corresponding to the reconstructed amplitudes is capable of being displayed as a three dimensional image of an adsorbate atom. The apparatus includes a source of a beam of low energy electrons and a detector for detecting the intensity distribution of a DLEED pattern formed at the detector when the beam of low energy electrons is directed onto the surface of a crystal. A device responsive to the intensity distribution generates a signal corresponding to the distribution which represents a reconstructed amplitude of a wave form and is capable of being converted into a three dimensional image of the atomic environment of an adsorbate atom on the crystal surface.

  6. Comparison of Wide-Bandgap Semiconductors for Power Electronics Applications

    SciTech Connect (OSTI)

    Ozpineci, B.

    2004-01-02T23:59:59.000Z

    Recent developmental advances have allowed silicon (Si) semiconductor technology to approach the theoretical limits of the Si material; however, power device requirements for many applications are at a point that the present Si-based power devices cannot handle. The requirements include higher blocking voltages, switching frequencies, efficiency, and reliability. To overcome these limitations, new semiconductor materials for power device applications are needed. For high power requirements, wide-bandgap semiconductors like silicon carbide (SiC), gallium nitride (GaN), and diamond, with their superior electrical properties, are likely candidates to replace Si in the near future. This report compares wide-bandgap semiconductors with respect to their promise and applicability for power applications and predicts the future of power device semiconductor materials.

  7. Horizontal film balance having wide range and high sensitivity

    DOE Patents [OSTI]

    Abraham, B.M.; Miyano, K.; Ketterson, J.B.

    1983-11-08T23:59:59.000Z

    A thin-film, horizontal balance instrument is provided for measuring surface tension (surface energy) of thin films suspended on a liquid substrate. The balance includes a support bearing and an optical feedback arrangement for wide-range, high sensitivity measurements. The force on the instrument is balanced by an electromagnet, the current through the magnet providing a measure of the force applied to the instrument. A novel float construction is also disclosed. 5 figs.

  8. Horizontal film balance having wide range and high sensitivity

    DOE Patents [OSTI]

    Abraham, Bernard M. (Oak Park, IL); Miyano, Kenjiro (Downers Grove, IL); Ketterson, John B. (Evanston, IL)

    1983-01-01T23:59:59.000Z

    A thin-film, horizontal balance instrument is provided for measuring surface tension (surface energy) of thin films suspended on a liquid substrate. The balance includes a support bearing and an optical feedback arrangement for wide-range, high sensitivity measurements. The force on the instrument is balanced by an electromagnet, the current through the magnet providing a measure of the force applied to the instrument. A novel float construction is also disclosed.

  9. Horizontal film balance having wide range and high sensitivity

    DOE Patents [OSTI]

    Abraham, B.M.; Miyano, K.; Ketterson, J.B.

    1981-03-05T23:59:59.000Z

    A thin-film, horizontal balance instrument is provided for measuring surface tension (surface energy) of thin films suspended on a liquid substrate. The balance includes a support bearing and an optical feedback arrangement for wide-range, high sensitivity measurements. The force on the instrument is balanced by an electromagnet, the current through the magnet providing a measure of the force applied to the instrument. A novel float construction is also disclosed.

  10. A Cosmology Calculator for the World Wide Web

    E-Print Network [OSTI]

    Edward L. Wright

    2006-10-10T23:59:59.000Z

    A cosmology calculator that computes times and distances as a function of redshift for user-defined cosmological parameters is available on the World Wide Web. This note gives the formulae used by the cosmology calculator and discusses some of its implementation. A version of the calculator that allows one to specify the equation of state parameter w and w' and neutrino masses, and a version for converting the light travel times usually given in the popular press into redshifts are also available.

  11. Dynamic polarizabilities of rare-earth-metal atoms and dispersion coefficients for their interaction with helium atoms

    E-Print Network [OSTI]

    Chu, Xi

    Dynamic polarizabilities of rare-earth-metal atoms and dispersion coefficients; published 29 March 2007 The dynamic scalar and tensor polarizabilities of the rare-earth-metal atoms coefficients for the interactions of the rare-earth-metal atoms with helium atoms. The static polarizabilities

  12. Optical pumping of a lithium atomic beam for atom interferometry J. Gillot, A. Gauguet, M. Buchner, and J. Vigue

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Optical pumping of a lithium atomic beam for atom interferometry J. Gillot, A. Gauguet, M. B.vigue@irsamc.ups-tlse.fr (Dated: May 29, 2013) We apply optical pumping to prepare the lithium beam of our atom interferometer in a single hyperfine-Zeeman sublevel: we use two components of the D1-line for pumping the 7 Li atoms

  13. Wide angle x-ray scattering of proteins : effect of beam exposure on protein integrity.

    SciTech Connect (OSTI)

    Fischetti, R. F.; Rodi, D. J.; Mirza, A.; Makowski, L.; Illinois Inst. of Tech.

    2003-01-01T23:59:59.000Z

    Wide-angle X-ray scattering patterns from proteins in solution contain information relevant to the determination of protein fold. At relevant scattering angles, however, these data are weak, and the degree to which they might be used to categorize the fold of a protein is unknown. Preliminary work has been performed at the BioCAT insertion-device beamline at the Advanced Photon Source which demonstrates that one can collect X-ray scattering data from proteins in solution to spacings of at least 2.2 {angstrom} (q = 2.8 {angstrom}-1). These data are sensitive to protein conformational states, and are in good agreement with the scattering predicted by the program CRYSOL using the known three-dimensional atomic coordinates of the protein. An important issue in the exploitation of this technique as a tool for structural genomics is the extent to which the high intensity of X-rays available at third-generation synchrotron sources chemically or structurally damage proteins. Various data-collection protocols have been investigated demonstrating conditions under which structural degradation of even sensitive proteins can be minimized, making this technique a viable tool for protein fold categorization, the study of protein folding, unfolding, protein-ligand interactions and domain movement.

  14. Atomic Scale Characterization of Compound Semiconductors using Atom Probe Tomography: Preprint

    SciTech Connect (OSTI)

    Gorman, B. P.; Guthrey, H.; Norman, A. G.; Al-Jassim, M.; Lawrence, D.; Prosa, T.

    2011-07-01T23:59:59.000Z

    Internal interfaces are critical in determining the performance of III-V multijunction solar cells. Studying these interfaces with atomic resolution using a combination of transmission electron microscopy (TEM), atom probe tomography (APT), and density functional calculations enables a more fundamental understanding of carrier dynamics in photovoltaic (PV) device structures. To achieve full atomic scale spatial and chemical resolution, data acquisition parameters in laser pulsed APT must be carefully studied to eliminate surface diffusion. Atom probe data with minimized group V ion clustering and expected stoichiometry can be achieved by adjusting laser pulse power, pulse repetition rate, and specimen preparation parameters such that heat flow away from the evaporating surface is maximized. Applying these improved analysis conditions to III-V based PV gives an atomic scale understanding of compositional and dopant profiles across interfaces and tunnel junctions and the initial stages of alloy clustering and dopant accumulation. Details on APT experimental methods and future in-situ instrumentation developments are illustrated.

  15. Wide-area situation awareness in electric power grid

    SciTech Connect (OSTI)

    Greitzer, Frank L.

    2010-04-28T23:59:59.000Z

    Two primary elements of the US energy policy are demand management and efficiency and renewable sources. Major objectives are clean energy transmission and integration, reliable energy transmission, and grid cyber security. Development of the Smart Grid seeks to achieve these goals by lowering energy costs for consumers, achieving energy independence and reducing greenhouse gas emissions. The Smart Grid is expected to enable real time wide-area situation awareness (SA) for operators. Requirements for wide-area SA have been identified among interoperability standards proposed by the Federal Energy Regulatory Commission and the National Institute of Standards and Technology to ensure smart-grid functionality. Wide-area SA and enhanced decision support and visualization tools are key elements in the transformation to the Smart Grid. This paper discusses human factors research to promote SA in the electric power grid and the Smart Grid. Topics that will be discussed include the role of human factors in meeting US energy policy goals, the impact and challenges for Smart Grid development, and cyber security challenges.

  16. Science with a wide-field UV transient explorer

    SciTech Connect (OSTI)

    Sagiv, I.; Gal-Yam, A.; Ofek, E. O.; Waxman, E.; Trakhtenbrot, B.; Topaz, J. [Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel); Aharonson, O. [Helen Kimmel Center for Planetary Science, Weizmann Institute of Science, 76100 Rehovot (Israel); Kulkarni, S. R.; Phinney, E. S. [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Nakar, E.; Maoz, D. [School of Physics and Astronomy, Tel Aviv University, 93387 Tel Aviv (Israel); Beichman, C. [Division of Geophysics and Planetary Science, California Institute of Technology, Pasadena, CA 91105 (United States); Murthy, J. [Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India); Worden, S. P. [NASA Ames Research Center, Moffett Field, CA 94035 (United States)

    2014-04-01T23:59:59.000Z

    The time-variable electromagnetic sky has been well-explored at a wide range of wavelengths. In contrast, the ultra-violet (UV) variable sky is relatively poorly explored, even though it offers exciting scientific prospects. Here, we review the potential scientific impact of a wide-field UV survey on the study of explosive and other transient events, as well as known classes of variable objects, such as active galactic nuclei and variable stars. We quantify our predictions using a fiducial set of observational parameters which are similar to those envisaged for the proposed ULTRASAT mission. We show that such a mission would be able to revolutionize our knowledge about massive star explosions by measuring the early UV emission from hundreds of events, revealing key physical parameters of the exploding progenitor stars. Such a mission would also detect the UV emission from many tens of tidal-disruption events of stars by supermassive black holes at galactic nuclei and enable a measurement of the rate of such events. The overlap of such a wide-field UV mission with existing and planned gravitational-wave and high-energy neutrino telescopes makes it especially timely.

  17. Recent progress in GaInAsSb thermophotovoltaics grown by organometallic vapor phase epitaxy

    SciTech Connect (OSTI)

    Wang, C.A.; Choi, H.K.; Oakley, D.C. [Massachusetts Inst. of Tech., Lexington, MA (United States). Lincoln Lab.; Charache, G.W. [Lockheed Martin, Inc., Schenectady, NY (United States)

    1998-06-01T23:59:59.000Z

    Studies on the materials development of Ga{sub 1{minus}x}In{sub x}As{sub y}Sb{sub 1{minus}y} alloys for thermophotovoltaic (TPV) devices are reviewed. Ga{sub 1{minus}x}In{sub x}As{sub y}Sb{sub 1{minus}y} epilayers were grown lattice matched to GaSb substrates by organometallic vapor phase epitaxy (OMVPE) using all organometallic precursors including triethylgallium, trimethylindium, tertiarybutylarsine, and trimethylantimony with diethyltellurium and dimethylzinc as the n- and p-type dopants, respectively. The overall material quality of these alloys depends on growth temperature, In content, V/III ratio, substrate misorientation, and to a lesser extent, growth rate. A mirror-like surface morphology and room temperature photoluminescence (PL) are obtained for GaInAsSb layers with peak emission in the wavelength range between 2 and 2.5 {micro}m. The crystal quality improves for growth temperature decreasing from 575 to 525 C, and with decreasing In content, as based on epilayer surface morphology and low temperature PL spectra. A trend of smaller full width at half-maximum for low temperature PL spectra is observed as the growth rate is increased from 1.5 to 2.5 and 5 {micro}m/h. In general, GaInAsSb layers grown on (100) GaSb substrates with a 6{degree} toward (111)B misorientation exhibited overall better material quality than layers grown on the more standard substrate (100)2{degree} toward (110). Consistent growth of high performance lattice-matched GaInAsSb TPV devices is also demonstrated.

  18. Carrier dynamics in Beryllium doped low-temperature-grown InGaAs/InAlAs

    SciTech Connect (OSTI)

    Globisch, B., E-mail: Bjoern.Globisch@hhi.fraunhofer.de; Dietz, R. J. B.; Stanze, D.; Göbel, T.; Schell, M. [Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute, Einsteinufer 37, 10587 Berlin (Germany)

    2014-04-28T23:59:59.000Z

    The electron and hole dynamics in low-temperature-grown InGaAs/InAlAs multiple quantum well structures are studied by optical pump-probe transmission measurements for Beryllium (Be) doping levels between 3?×?10{sup 17}?cm{sup ?3} and 4?×?10{sup 18}?cm{sup ?3}. We investigate electron dynamics in the limit cases of unsaturated and completely saturated electron trapping. By expanding a rate equation model in these limits, the details of carrier dynamics are revealed. Electrons are trapped by ionized arsenic antisites, whereas recombination occurs between trapped electrons and holes trapped by negatively charged Be dopants.

  19. Fundamental optical properties of InN grown by epitaxial lateral overgrowth method

    SciTech Connect (OSTI)

    Kametani, Tatsuma; Kamimura, Jumpei; Inose, Yuta; Kunugita, Hideyuki; Kikuchi, Akihiko; Kishino, Katsumi; Ema, Kazuhiro [Department of Engineering and Applied Science, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554 (Japan)

    2013-12-04T23:59:59.000Z

    Optical properties of InN grown by the epitaxial lateral overgrowth (ELO) method have been studied using photoluminescence (PL) and excitation-correlation (EC) measurements. The PL spectrum is analyzed by free-electron recombination band (FERB) model, which shows that the ELO sample has a very low background carrier concentration (n=5.5*10{sup 16}[cm{sup ?3]}). EC measurements show that the dependences of the band gap renormalization and Auger effect on the carrier concentrations are similar in spite of the different physical origins.

  20. The Hall mobility measurement of Liquid Phase Epitaxy grown aluminum gallium arsenide

    E-Print Network [OSTI]

    Choi, Young-Shig

    1986-01-01T23:59:59.000Z

    -type AJGaAs mobility as a function of doping concentration with temperature as a, parameter. . 51 CHAPTER I INTRODUCTION AI?Ga& ?As (x is the mole fraction of Al) has been employed to fabricate discrete Light Emitting Diodes (LED) and Laser Diodes... grown l&y 1. PE are the lasers and light, -emitting diodes, 2, 31. 10 One limitation of the LPE technique is the difficulty of growing layers that differ in lattice constant by more than lv/& from the substrate. Lattice mismatch, occuring whenever...

  1. Characterization of GaN microstructures grown by plasma-assisted molecular beam epitaxy

    SciTech Connect (OSTI)

    Lo, Ikai; Pang, Wen-Yuan; Hsu, Yu-Chi; Hsieh, Chia-Ho; Shih, Cheng-Hung; Chou, Mitch M. C. [Department of Physics and Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Chen, Wen-Yen; Hsu, Tzu-Min [Department of Physics, National Central University, Jhong-li, Taoyuan 32001, Taiwan (China); Hsu, Gary Z. L. [United Crystal Corporation, No.243-3, Wenshan, 36061, Miaoli, Taiwan (China)

    2013-06-15T23:59:59.000Z

    The characterization of GaN microstructures grown by plasma-assisted molecular beam epitaxy on LiAlO{sub 2} substrate was studied by cathodoluminescence and photoluminescence measurements. We demonstrated that the cathodoluminescence from oblique semi-polar surfaces of mushroom-shaped GaN was much brighter than that from top polar surface due to the reduction of polarization field on the oblique semi-polar surfaces. It implies that the oblique semi-polar surface is superior for the light-emitting surface of wurtzite nano-devices.

  2. III-nitride quantum cascade detector grown by metal organic chemical vapor deposition

    SciTech Connect (OSTI)

    Song, Yu, E-mail: yusong@princeton.edu; Huang, Tzu-Yung; Badami, Pranav; Gmachl, Claire [Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08540 (United States); Bhat, Rajaram; Zah, Chung-En [Corning Incorporated, Corning, New York 14831 (United States)

    2014-11-03T23:59:59.000Z

    Quantum cascade (QC) detectors in the GaN/Al{sub x}Ga{sub 1?x}N material system grown by metal organic chemical vapor deposition are designed, fabricated, and characterized. Only two material compositions, i.e., GaN as wells and Al{sub 0.5}Ga{sub 0.5}N as barriers are used in the active layers. The QC detectors operates around 4??m, with a peak responsivity of up to ?100??A/W and a detectivity of up to 10{sup 8} Jones at the background limited infrared performance temperature around 140?K.

  3. The Vitamin D Requirements of Chickens Grown in the Absence of Sunlight.

    E-Print Network [OSTI]

    Couch, James Russell; Fraps, G. S. (George Stronach); Sherwood, R. M. (Ross Madison)

    1935-01-01T23:59:59.000Z

    * * 'n~$p?ip~ln 1( @ JC;',~ ,W&qpJ- '~''fi~fi eyp+:3n 7 a ?ypy THE VITAMIN D REQUIREMENTS OF CHICKENS GROWN IN THE ABSENCE OF SUNLIGHT AGRICULTURAL A.ND MECHANICAL COLLEGE OF' TEXAS T. 0. WALTON, President These experiments i...~lclicnte that chickens fed a ration with the proper amounts of calcium and phosphorus need no additional vitamin D to make good growth for the first six weeks even in the absence of sunlight. The vitamin D requirenlent of the cockerel appears to be higher than...

  4. Epitaxial growth of 100-?m thick M-type hexaferrite crystals on wide bandgap semiconductor GaN/Al{sub 2}O{sub 3} substrates

    SciTech Connect (OSTI)

    Hu, Bolin; Su, Zhijuan; Bennett, Steve; Chen, Yajie, E-mail: y.chen@neu.edu; Harris, Vincent G. [Center for Microwave Magnetic Materials and Integrated Circuits and Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States)

    2014-05-07T23:59:59.000Z

    Thick barium hexaferrite BaFe{sub 12}O{sub 19} (BaM) films having thicknesses of ?100??m were epitaxially grown on GaN/Al{sub 2}O{sub 3} substrates from a molten-salt solution by vaporizing the solvent. X-ray diffraction measurement verified the growth of BaM (001) textured growth of thick films. Saturation magnetization, 4?M{sub s}, was measured for as-grown films to be 4.6 ± 0.2 kG and ferromagnetic resonance measurements revealed a microwave linewidth of ?100?Oe at X-band. Scanning electron microscopy indicated clear hexagonal crystals distributed on the semiconductor substrate. These results demonstrate feasibility of growing M-type hexaferrite crystal films on wide bandgap semiconductor substrates by using a simple powder melting method. It also presents a potential pathway for the integration of ferrite microwave passive devices with active semiconductor circuit elements creating system-on-a-wafer architectures.

  5. Atomic multipole relaxation rates near surfaces

    E-Print Network [OSTI]

    J. A. Crosse; Stefan Scheel

    2010-08-13T23:59:59.000Z

    The spontaneous relaxation rates for an atom in free space and close to an absorbing surface are calculated to various orders of the electromagnetic multipole expansion. The spontaneous decay rates for dipole, quadrupole and octupole transitions are calculated in terms of their respective primitive electric multipole moments and the magnetic relaxation rate is calculated for the dipole and quadrupole transitions in terms of their respective primitive magnetic multipole moments. The theory of electromagnetic field quantization in magnetoelectric materials is used to derive general expressions for the decay rates in terms of the dyadic Green function. We focus on the decay rates in free space and near an infinite half space. For the decay of atoms near to an absorbing dielectric surface we find a hierarchy of scaling laws depending on the atom-surface distance z.

  6. Atom interferometry in an optical cavity

    E-Print Network [OSTI]

    Paul Hamilton; Matt Jaffe; Justin M. Brown; Lothar Maisenbacher; Brian Estey; Holger Müller

    2014-09-25T23:59:59.000Z

    We propose and demonstrate a new scheme for atom interferometry, using light pulses inside an optical cavity as matter wave beamsplitters. The cavity provides power enhancement, spatial filtering, and a precise beam geometry, enabling new techniques such as low power beamsplitters ($modest power, or new self-aligned interferometer geometries utilizing the transverse modes of the optical cavity. As a first demonstration, we obtain Ramsey-Raman fringes with $>75\\%$ contrast and measure the acceleration due to gravity, $\\mathit{g}$, to $60 \\mathrm{\\mu \\mathit{g} / \\sqrt{Hz}}$ resolution in a Mach-Zehnder geometry. We use $>10^7$ cesium atoms in the compact mode volume ($600 \\mathrm{\\mu m}$ $1/e^2$ waist) of the cavity and show trapping of atoms in higher transverse modes. This work paves the way toward compact, high sensitivity, multi-axis interferometry.

  7. Atomic Rydberg Reservoirs for Polar Molecules

    E-Print Network [OSTI]

    Zhao, Bo; Pupillo, Guido; Zoller, Peter

    2011-01-01T23:59:59.000Z

    We discuss laser dressed dipolar and Van der Waals interactions between atoms and polar molecules, so that a cold atomic gas with laser admixed Rydberg levels acts as a designed reservoir for both elastic and inelastic collisional processes. The elastic scattering channel is characterized by large elastic scattering cross sections and repulsive shields to protect from close encounter collisions. In addition, we discuss a dissipative (inelastic) collision where a spontaneously emitted photon carries away (kinetic) energy of the collision partners, thus providing a significant energy loss in a single collision. This leads to the scenario of rapid thermalization and cooling of a molecule in the mK down to the \\mu K regime by cold atoms.

  8. Atomic Rydberg Reservoirs for Polar Molecules

    E-Print Network [OSTI]

    Bo Zhao; Alexander Glätzle; Guido Pupillo; Peter Zoller

    2011-12-18T23:59:59.000Z

    We discuss laser dressed dipolar and Van der Waals interactions between atoms and polar molecules, so that a cold atomic gas with laser admixed Rydberg levels acts as a designed reservoir for both elastic and inelastic collisional processes. The elastic scattering channel is characterized by large elastic scattering cross sections and repulsive shields to protect from close encounter collisions. In addition, we discuss a dissipative (inelastic) collision where a spontaneously emitted photon carries away (kinetic) energy of the collision partners, thus providing a significant energy loss in a single collision. This leads to the scenario of rapid thermalization and cooling of a molecule in the mK down to the \\mu K regime by cold atoms.

  9. Searching for dark matter with helium atom

    E-Print Network [OSTI]

    Imre Ferenc Barna

    2006-08-10T23:59:59.000Z

    With the help of the boost operator we can model the interaction between a weakly interacting particle(WIMP) of dark matter(DAMA) and an atomic nuclei. Via this "kick" we calculate the total electronic excitation cross section of the helium atom. The bound spectrum of He is calculated through a diagonalization process with a configuration interaction (CI) wavefunction built up from Slater orbitals. All together 19 singly- and doubly-excited atomic sates were taken with total angular momenta of L=0,1 and 2. Our calculation may give a rude estimation about the magnitude of the total excitation cross section which could be measured in later scintillator experiments. The upper limit of the excitation cross section is $9.7\\cdot 10^{-8}$ barn.

  10. Atom Interferometers and the Gravitational Redshift

    E-Print Network [OSTI]

    Supurna Sinha; Joseph Samuel

    2011-05-16T23:59:59.000Z

    From the principle of equivalence, Einstein predicted that clocks slow down in a gravitational field. Since the general theory of relativity is based on the principle of equivalence, it is essential to test this prediction accurately. Muller, Peters and Chu claim that a reinterpretation of decade old experiments with atom interferometers leads to a sensitive test of this gravitational redshift effect at the Compton frequency. Wolf et al dispute this claim and adduce arguments against it. In this article, we distill these arguments to a single fundamental objection: an atom is NOT a clock ticking at the Compton frequency. We conclude that atom interferometry experiments conducted to date do not yield such sensitive tests of the gravitational redshift. Finally, we suggest a new interferometric experiment to measure the gravitational redshift, which realises a quantum version of the classical clock "paradox".

  11. New charge radius relations for atomic nuclei

    E-Print Network [OSTI]

    B. H. Sun; Y. Lu; J. P. Peng; C. Y. Liu; Y. M. Zhao

    2014-11-24T23:59:59.000Z

    We show that the charge radii of neighboring atomic nuclei, independent of atomic number and charge, follow remarkably very simple relations, despite the fact that atomic nuclei are complex finite many-body systems governed by the laws of quantum mechanics. These relations can be understood within the picture of independent-particle motion and by assuming neighboring nuclei having similar pattern in the charge density distribution. A root-mean-square (rms) deviation of 0.0078 fm is obtained between the predictions in these relations and the experimental values, i.e., a comparable precision as modern experimental techniques. Such high accuracy relations are very useful to check the consistence of nuclear charge radius surface and moreover to predict unknown nuclear charge radii, while large deviations from experimental data is seen to reveal the appearance of nuclear shape transition or coexsitence.

  12. Feedback Cooling of a Single Neutral Atom

    E-Print Network [OSTI]

    Markus Koch; Christian Sames; Alexander Kubanek; Matthias Apel; Maximilian Balbach; Alexei Ourjoumtsev; Pepijn W. H. Pinkse; Gerhard Rempe

    2010-10-15T23:59:59.000Z

    We demonstrate feedback cooling of the motion of a single rubidium atom trapped in a high-finesse optical resonator to a temperature of about 160 \\mu K. Time-dependent transmission and intensity-correlation measurements prove the reduction of the atomic position uncertainty. The feedback increases the 1/e storage time into the one second regime, 30 times longer than without feedback. Feedback cooling therefore rivals state-of-the-art laser cooling, but with the advantages that it requires less optical access and exhibits less optical pumping.

  13. Proton Mass Shift in Muonic Hydrogen Atom

    E-Print Network [OSTI]

    Aiichi Iwazaki

    2014-08-11T23:59:59.000Z

    We show that the value of the proton mass depends on each bound state of muonic or electronic hydrogen atom. The charged particle bound to the proton produces magnetic field inside the proton. This makes a change to the amount of chiral condensate inside the proton. The change gives rise to the shift in the value of the proton mass. Numerically, the shift in the $2S$ state of the muonic hydrogen atom can be of the order of $0.1$ meV. The effect may solve the puzzle of the proton radius.

  14. Magnetic field imaging with atomic Rb vapor

    E-Print Network [OSTI]

    Eugeniy E. Mikhailov; I. Novikova; M. D. Havey; F. A. Narducci

    2009-07-27T23:59:59.000Z

    We demonstrate the possibility of dynamic imaging of magnetic fields using electromagnetically induced transparency in an atomic gas. As an experimental demonstration we employ an atomic Rb gas confined in a glass cell to image the transverse magnetic field created by a long straight wire. In this arrangement, which clearly reveals the essential effect, the field of view is about 2 x 2 mm^2 and the field detection uncertainty is 0.14 mG per 10 um x 10 um image pixel.

  15. Probing Dark Energy with Atom Interferometry

    E-Print Network [OSTI]

    Clare Burrage; Edmund J. Copeland; E. A. Hinds

    2014-08-06T23:59:59.000Z

    Theories of dark energy require a screening mechanism to explain why the associated scalar fields do not mediate observable long range fifth forces. The archetype of this is the chameleon field. Here we show that individual atoms are too small to screen the chameleon field inside a large high-vacuum chamber, and therefore can detect the field with high sensitivity. We derive new limits on the chameleon parameters from existing experiments, and show that most of the remaining chameleon parameter space is readily accessible using atom interferometry.

  16. AtomsPeace_Dec2003.qxd

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041cloth DocumentationProductsAlternativeOperational ManagementDemand ModuleNationalAtomic,Atoms for

  17. High-speed force mapping on living cells with a small cantilever atomic force microscope

    SciTech Connect (OSTI)

    Braunsmann, Christoph; Seifert, Jan; Rheinlaender, Johannes; Schäffer, Tilman E., E-mail: Tilman.Schaeffer@uni-tuebingen [Institute of Applied Physics and LISA, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen (Germany)

    2014-07-15T23:59:59.000Z

    The imaging speed of the wide-spread force mapping mode for quantitative mechanical measurements on soft samples in liquid with the atomic force microscope (AFM) is limited by the bandwidth of the z-scanner and viscous drag forces on the cantilever. Here, we applied high-speed, large scan-range atomic force microscopy and small cantilevers to increase the speed of force mapping by ?10?100 times. This allowed resolving dynamic processes on living mouse embryonic fibroblasts. Cytoskeleton reorganization during cell locomotion, growth of individual cytoskeleton fibers, cell blebbing, and the formation of endocytic pits in the cell membrane were observed. Increasing the force curve rate from 2 to 300 Hz increased the measured apparent Young's modulus of the cells by about 10 times, which facilitated force mapping measurements at high speed.

  18. Atom probe analysis of interfacial abruptness and clustering within a single In{sub x}Ga{sub 1-x}N quantum well device on semipolar (1011) GaN substrate

    SciTech Connect (OSTI)

    Prosa, T. J.; Clifton, P. H. [Cameca Instruments Inc., Madison, Wisconsin 53711 (United States); Zhong, H.; Shivaraman, R.; Speck, J. S. [Department of Materials, University of California, Santa Barbara, California 93106 (United States); Tyagi, A.; DenBaars, S. P.; Nakamura, S. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States)

    2011-05-09T23:59:59.000Z

    Pulsed laser atom probe tomography (APT) of In{sub x}Ga{sub 1-x}N single quantum well (SQW) grown on semipolar (1011) GaN orientation estimates the interior atomic composition within the SQW at 6.5{+-}0.7 at. % In, 46.2{+-}0.7 at. % Ga, and 47.3{+-}0.7 at. % N. The atom probe analysis is performed in both 'top-down' and 'cross-section' orientations. Self-consistent Schroedinger-Poisson simulation employing structural and compositional parameters obtained from APT results estimates the polarization field within the SQW at 720 kV/cm. A statistical method for the evaluation of indium homogeneity within the SQW is also considered.

  19. Atom probe analysis of interfacial abruptness and clustering within a single In{sub x}Ga{sub 1-x}N quantum well device on semipolar (10{bar 1}{bar 1}) GaN substrate

    SciTech Connect (OSTI)

    Prosa, T. J.; Clifton, P. H.; Zhong, H.; Tyagi, A.; Shivaraman, R.; DenBaars, S. P.; Nakamura, S.; Speck, J. S.

    2011-01-01T23:59:59.000Z

    Pulsed laser atom probe tomography (APT) of In{sub x}Ga{sub 1?x}N single quantum well (SQW) grown on semipolar (10{bar 1}{bar 1})GaN orientation estimates the interior atomic composition within the SQW at 6.5±0.7?at.?% In, 46.2±0.7?at.?% Ga, and 47.3±0.7?at.?% N. The atom probe analysis is performed in both “top-down” and “cross-section” orientations. Self-consistent Schrödinger–Poisson simulation employing structural and compositional parameters obtained from APT results estimates the polarization field within the SQW at 720 kV/cm. A statistical method for the evaluation of indium homogeneity within the SQW is also considered.

  20. Comparison of Chloroflexus aurantiacus strain J-10-fl proteomes of cells grown chemoheterotrophically and photoheterotrophically

    SciTech Connect (OSTI)

    Cao, Li; Bryant, Donald A.; Schepmoes, Athena A.; Vogl, Kajetan; Smith, Richard D.; Lipton, Mary S.; Callister, Stephen J.

    2012-01-17T23:59:59.000Z

    Chloroflexus aurantiacus J-10-fl is a thermophilic green bacterium, a filamentous anoxygenic phototroph, and the model organism of the phylum Chloroflexi. We applied high-throughput, liquid chromatography-mass spectrometry in a global quantitative proteomics investigation of C. aurantiacus cells grown under oxic (chemoorganoheterotrophically) and anoxic (photoorganoheterotrophically) redox states. Our global analysis identified 13,524 high-confidence peptides that matched to 1,286 annotated proteins, 242 of which were either uniquely identified or significantly increased in abundance under anoxic culture conditions. Fifty-three of the 242 proteins are previously characterized photosynthesis-related proteins, including chlorosome proteins, proteins involved in the bacteriochlorophyll biosynthesis, 3-hydroxypropionate (3-OHP) CO2 fixation pathway, and components of electron transport chains. The remaining 190 proteins have not previously been reported. Of these, five proteins were found to be encoded by genes from a novel operon and observed only in photoheterotrophically grown cells. These proteins candidates may prove useful in further deciphering the phototrophic physiology of C. aurantiacus and other filamentous anoxygenic phototrophs.

  1. Characterization of Epitaxial Film Silicon Solar Cells Grown on Seeded Display Glass: Preprint

    SciTech Connect (OSTI)

    Young, D. L.; Grover, S.; Teplin, C.; Stradins, P.; LaSalvia, V.; Chuang, T. K.; Couillard, J. G.; Branz, H. M.

    2012-06-01T23:59:59.000Z

    We report characterizations of epitaxial film crystal silicon (c-Si) solar cells with open-circuit voltages (Voc) above 560 mV. The 2-um absorber cells are grown by low-temperature (<750 degrees C) hot-wire CVD (HWCVD) on Corning EAGLE XG display glass coated with a layer-transferred (LT) Si seed. The high Voc is a result of low-defect epitaxial Si (epi-Si) growth and effective hydrogen passivation of defects. The quality of HWCVD epitaxial growth on seeded glass substrates depends on the crystallographic quality of the seed and the morphology of the epitaxial growth surface. Heterojunction devices consist of glass/c-Si LT seed/ epi n+ Si:P/epi n- Si:P/intrinsic a-Si:H/p+ a-Si:H/ITO. Similar devices grown on electronically 'dead' n+ wafers have given Voc {approx}630 mV and {approx}8% efficiency with no light trapping features. Here we study the effects of the seed surface polish on epi-Si quality, how hydrogenation influences the device character, and the dominant junction transport physics.

  2. Effect of e-beam irradiation on graphene layer grown by chemical vapor deposition

    SciTech Connect (OSTI)

    Iqbal, M. Z.; Kumar Singh, Arun; Iqbal, M. W.; Seo, Sunae; Eom, Jonghwa [Department of Physics and Graphene Research Institute, Sejong University, Seoul 143-747 (Korea, Republic of)

    2012-04-15T23:59:59.000Z

    We have grown graphene by chemical vapor deposition (CVD) and transferred it onto Si/SiO{sub 2} substrates to make tens of micron scale devices for Raman spectroscopy study. The effect of electron beam (e-beam) irradiation of various doses (600 to 12 000 {mu}C/cm{sup 2}) on CVD grown graphene has been examined by using Raman spectroscopy. It is found that the radiation exposures result in the appearance of the strong disorder D band attributed the damage to the lattice. The evolution of peak frequencies, intensities, and widths of the main Raman bands of CVD graphene is analyzed as a function of defect created by e-beam irradiation. Especially, the D and G peak evolution with increasing radiation dose follows the amorphization trajectory, which suggests transformation of graphene to the nanocrystalline and then to amorphous form. We have also estimated the strain induced by e-beam irradiation in CVD graphene. These results obtained for CVD graphene are in line with previous findings reported for the mechanically exfoliated graphene [D. Teweldebrhan and A. A. Balandin, Appl. Phys. Lett. 94, 013101 (2009)]. The results have important implications for CVD graphene characterization and device fabrication, which rely on the electron microscopy.

  3. Group III-nitride thin films grown using MBE and bismuth

    DOE Patents [OSTI]

    Kisielowski, Christian K. (Peidmont, CA); Rubin, Michael (Berkeley, CA)

    2000-01-01T23:59:59.000Z

    The present invention comprises growing gallium nitride films in the presence of bismuth using MBE at temperatures of about 1000 K or less. The present invention further comprises the gallium nitride films fabricated using the inventive fabrication method. The inventive films may be doped with magnesium or other dopants. The gallium nitride films were grown on sapphire substrates using a hollow anode Constricted Glow Discharge nitrogen plasma source. When bismuth was used as a surfactant, two-dimensional gallium nitride crystal sizes ranging between 10 .mu.m and 20 .mu.m were observed. This is 20 to 40 times larger than crystal sizes observed when GaN films were grown under similar circumstances but without bismuth. It is thought that the observed increase in crystal size is due bismuth inducing an increased surface diffusion coefficient for gallium. The calculated value of 4.7.times.10.sup.-7 cm.sup.2 /sec. reveals a virtual substrate temperature of 1258 K which is 260 degrees higher than the actual one.

  4. Group III-nitride thin films grown using MBE and bismuth

    DOE Patents [OSTI]

    Kisielowski, Christian K. (Piedmont, CA); Rubin, Michael (Berkeley, CA)

    2002-01-01T23:59:59.000Z

    The present invention comprises growing gallium nitride films in the presence of bismuth using MBE at temperatures of about 1000 K or less. The present invention further comprises the gallium nitride films fabricated using the inventive fabrication method. The inventive films may be doped with magnesium or other dopants. The gallium nitride films were grown on sapphire substrates using a hollow anode Constricted Glow Discharge nitrogen plasma source. When bismuth was used as a surfactant, two-dimensional gallium nitride crystal sizes ranging between 10 .mu.m and 20 .mu.m were observed. This is 20 to 40 times larger than crystal sizes observed when GaN films were grown under similar circumstances but without bismuth. It is thought that the observed increase in crystal size is due bismuth inducing an increased surface diffusion coefficient for gallium. The calculated value of 4.7.times.10.sup.-7 cm.sup.2 /sec. reveals a virtual substrate temperature of 1258 K which is 260 degrees higher than the actual one.

  5. Sensing performances of ZnO nanostructures grown under different oxygen pressures to hydrogen

    SciTech Connect (OSTI)

    Chu, Jin; Peng, Xiaoyan [Department of Physics, University of Puerto Rico Rio Piedras, San Juan, 00936-8377 PR (United States)] [Department of Physics, University of Puerto Rico Rio Piedras, San Juan, 00936-8377 PR (United States); Wang, Zhenbo [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)] [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Feng, Peter, E-mail: P.feng@upr.edu [Department of Physics, University of Puerto Rico Rio Piedras, San Juan, 00936-8377 PR (United States)] [Department of Physics, University of Puerto Rico Rio Piedras, San Juan, 00936-8377 PR (United States)

    2012-12-15T23:59:59.000Z

    Graphical abstract: Display Omitted Highlights: ? Surface morphology depends on the oxygen pressure. ? Structural degradation was observed for the ZnO samples when oxygen pressure was overhigh. ? The sensitivity of the ZnO-based sensors increase with grown oxygen pressure. -- Abstract: For extensive use in an industrialized process of individual ZnO nanostructures applied in gas sensors, a simple, inexpensive, and safe synthesis process is required. Here, nanostructured ZnO films were grown by a pulsed laser deposition technique under different oxygen pressures. Scanning electron microscopy images show nanopores, nanotips, and nanoparticles are obtained and energy dispersive X-ray spectroscopy data indicate oxygen concentration of the synthesized samples increases monotonously with oxygen pressure. The sensor based on ZnO with high oxygen concentration has high sensitivity, rapid response (9 s) and recovery (80 s) behavior to 500 ppm hydrogen below 150 °C. Experimental data indicate that high oxygen concentration effectively improves the sensing properties of nanostructured ZnO.

  6. Extreme multiplex spectroscopy at wide-field 4-m telescopes

    E-Print Network [OSTI]

    Robert Content; Tom Shanks

    2008-08-18T23:59:59.000Z

    We describe the design and science case for a spectrograph for the prime focus of classical 4-m wide-field telescopes that can deliver at least 4000 MOS slits over a 1 degree field. This extreme multiplex capability means that 25000 galaxy redshifts can be measured in a single night, opening up the possibilities for large galaxy redshift surveys out to z~0.7 and beyond for the purpose of measuring the Baryon Acoustic Oscillation (BAO) scale and for many other science goals. The design features four cloned spectrographs and exploits the exclusive possibility of tiling the focal plane of wide-field 4-m telescopes with CCDs for multi-object spectroscopic purposes. In ~200 night projects, such spectrographs have the potential to make galaxy redshift surveys of ~6 million galaxies over a wide redshift range and thus may provide a low-cost alternative to other survey routes such as WFMOS and SKA. Two of these extreme multiplex spectrographs are currently being designed for the AAT (NG1dF) and Calar Alto (XMS) 4-m class telescopes. NG2dF, a larger version for the AAT 2 degree field, would have 12 clones and at least 12000 slits. The clones use a transparent design including a grism in which all optics are smaller than the clone square subfield so that the clones can be tightly packed with little gaps between the contiguous fields. Only low cost glasses are used; the variations in chromatic aberrations between bands are compensated by changing one or two of the lenses adjacent to the grism. The total weight and length is smaller with a few clones than a unique spectrograph which makes it feasible to place the spectrograph at the prime focus.

  7. The Wide Field Spectrograph (WiFeS)

    E-Print Network [OSTI]

    Michael Dopita; John Hart; Peter McGregor; Patrick Oates; Gabe Bloxham; Damien Jones

    2007-05-02T23:59:59.000Z

    This paper describes the Wide Field Spectrograph (WiFeS) under construction at the Research School of Astronomy and Astrophysics (RSAA) of the Australian National University (ANU) for the ANU 2.3m telescope at the Siding Spring Observatory. WiFeS is a powerful integral field, double-beam, concentric, image-slicing spectrograph designed to deliver excellent thoughput, wavelength stability, spectrophotometric performance and superb image quality along with wide spectral coverage throughout the 320-950 nm wavelength region. It provides a 25x38 arcsec. field with 0.5 arcsec. sampling along each of twenty five 38X1 arcsec slitlets. The output format is optimized to match the 4096x4096 pixel CCD detectors in each of two cameras individually optimized for the blue and the red ends of the spectrum, respectively. A process of "interleaved nod-and-shuffle" will be applied to permit quantum noise-limited sky subtraction. Using VPH gratings, spectral resolutions of 3000 and 7000 are provided. The full spectral range is covered in a single exposure at R=3000, and in two exposures in the R=7000 mode. The use of transmissive coated optics, VPH gratings and optimized mirror coatings ensures a throughput (including telescope atmosphere and detector) > 30% over a wide spectral range. The concentric image-slicer design ensures an excellent and uniform image quality across the full field. To maximize scientific return, the whole instrument is configured for remote observing, pipeline data reduction, and the accumulation of calibration image libraries.

  8. Development of Autonomous Magnetometer Rotorcraft For Wide Area Assessment

    SciTech Connect (OSTI)

    Mark D. McKay; Matthew O. Anderson

    2011-08-01T23:59:59.000Z

    Large areas across the United States and internationally are potentially contaminated with unexploded ordinance (UXO), with some ranges encompassing tens to hundreds of thousands of acres. Technologies are needed which will allow for cost effective wide area scanning with (1) near 100% coverage and (2) near 100% detection of subsurface ordnance or features indicative of subsurface ordnance. The current approach to wide area assessment is a multi-level one, in which medium - altitude fixed wing optical imaging is used for an initial site assessment. This assessment is followed with low altitude manned helicopter based magnetometry. Subsequent to this wide area assessment targeted surface investigations are performed using either towed geophysical sensor arrays or man portable sensors. In order to be an effective tool for small UXO detection, the sensing altitude for magnetic site investigations needs to be on the order of 1 to 3 meters. These altitude requirements mean that manned helicopter surveys will generally only be feasible in large, open and relatively flat terrains. While such surveys are effective in mapping large areas relatively fast there are substantial mobilization/demobilization, staffing and equipment costs associated with these surveys, resulting in costs of approximately $100-$150/acre. In addition, due to the low altitude there are substantial risks to pilots and equipment. Surface towed arrays provide highresolution maps but have other limitations, e.g. in their ability to navigate rough terrain effectively. Thus there is a need for other systems, which can be used for effective data collection. An Unmanned Aerial Vehicle (UAV) magnetometer platform is an obvious alternative. The motivation behind such a system is that it reduces risk to operators, is lower in initial and Operational and Maintenance (O&M) costs (and can thus potentially be applied to smaller sites) and has the potential of being more effective in terms of detection and possibly characterization (through the use of dynamic acquisition, i.e. survey mission in-flight reprioritization).

  9. Atomic-scale observation of parallel development of super elasticity and reversible plasticity in GaAs nanowires

    SciTech Connect (OSTI)

    Bao, Peite; Du, Sichao; Zheng, Rongkun, E-mail: rongkun.zheng@sydney.edu.au [School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia); Wang, Yanbo; Liao, Xiaozhou, E-mail: xiaozhou.liao@sydney.edu.au [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Cui, Xiangyuan; Yen, Hung-Wei; Kong Yeoh, Wai; Ringer, Simon P. [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006 (Australia); Gao, Qiang; Hoe Tan, H.; Jagadish, Chennupati [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Liu, Hongwei [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006 (Australia); Zou, Jin [Materials Engineering and Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD 4072 (Australia)

    2014-01-13T23:59:59.000Z

    We report the atomic-scale observation of parallel development of super elasticity and reversible dislocation-based plasticity from an early stage of bending deformation until fracture in GaAs nanowires. While this phenomenon is in sharp contrast to the textbook knowledge, it is expected to occur widely in nanostructures. This work indicates that the super recoverable deformation in nanomaterials is not simple elastic or reversible plastic deformation in nature, but the coupling of both.

  10. Wide band cryogenic ultra-high vacuum microwave absorber

    DOE Patents [OSTI]

    Campisi, Isidoro E. (Newport News, VA)

    1992-01-01T23:59:59.000Z

    An absorber wave guide assembly for absorbing higher order modes of microwave energy under cryogenic ultra-high vacuum conditions, that absorbs wide-band multi-mode energy. The absorber is of a special triangular shape, made from flat tiles of silicon carbide and aluminum nitride. The leading sharp end of the absorber is located in a corner of the wave guide and tapers to a larger cross-sectional area whose center is located approximately in the center of the wave guide. The absorber is relatively short, being of less height than the maximum width of the wave guide.

  11. Wide band cryogenic ultra-high vacuum microwave absorber

    DOE Patents [OSTI]

    Campisi, I.E.

    1992-05-12T23:59:59.000Z

    An absorber waveguide assembly for absorbing higher order modes of microwave energy under cryogenic ultra-high vacuum conditions, that absorbs wide-band multi-mode energy. The absorber is of a special triangular shape, made from flat tiles of silicon carbide and aluminum nitride. The leading sharp end of the absorber is located in a corner of the waveguide and tapers to a larger cross-sectional area whose center is located approximately in the center of the wave guide. The absorber is relatively short, being of less height than the maximum width of the waveguide. 11 figs.

  12. EM Corporate Performance Measures - Complex Wide | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny:Revised FindingDepartmentDepartmentStatementEnergy EMEMofComplex Wide EM

  13. Wide range H[sub 2] sensor using catalytic alloys

    SciTech Connect (OSTI)

    Hughes, R.C.; Buss, R.J.; Reynolds, S.W.; Jenkins, M.W.; Rodriguez, J.L.

    1992-01-01T23:59:59.000Z

    A new Wide Range Hydrogen Sensor fabricated on a silicon chip is described. A single die measuring 4 mm by 4 mm has four different kinds of hydrogen sensors, a heater and a temperature-measuring thin metalfilm. Chemiresistors made from thin films of a Pd/Ni alloy give an accurate measure of hydrogen concentrations from 0.1 to 100%, while Metal-Insulator-Silicon (MIS) capacitors are used for hydrogen concentrations down to about 1 ppM. A microprocessor controlled circuit is described that combines temperature control and signal processing.

  14. Wide range H{sub 2} sensor using catalytic alloys

    SciTech Connect (OSTI)

    Hughes, R.C.; Buss, R.J.; Reynolds, S.W.; Jenkins, M.W.; Rodriguez, J.L.

    1992-12-31T23:59:59.000Z

    A new Wide Range Hydrogen Sensor fabricated on a silicon chip is described. A single die measuring 4 mm by 4 mm has four different kinds of hydrogen sensors, a heater and a temperature-measuring thin metalfilm. Chemiresistors made from thin films of a Pd/Ni alloy give an accurate measure of hydrogen concentrations from 0.1 to 100%, while Metal-Insulator-Silicon (MIS) capacitors are used for hydrogen concentrations down to about 1 ppM. A microprocessor controlled circuit is described that combines temperature control and signal processing.

  15. Securing Wide Area Measurement Systems | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the.pdfBreakingMay 2015ParentsMiddle| DepartmentAchievementEnergyWide Area Measurement

  16. Sandia Energy - Sandia Wide-Bandgap Semiconductor Workshop

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del Sol Home Distribution GridDocuments HomeDatabase on EngineATeachesWide-Bandgap

  17. Resolving three-dimensional shape of sub-50?nm wide lines with nanometer-scale sensitivity using conventional optical microscopes

    SciTech Connect (OSTI)

    Attota, Ravikiran, E-mail: Ravikiran.attota@nist.gov; Dixson, Ronald G. [Semiconductor and Dimensional Metrology Division, NIST, Gaithersburg, Maryland 20899 (United States)

    2014-07-28T23:59:59.000Z

    We experimentally demonstrate that the three-dimensional (3-D) shape variations of nanometer-scale objects can be resolved and measured with sub-nanometer scale sensitivity using conventional optical microscopes by analyzing 4-D optical data using the through-focus scanning optical microscopy (TSOM) method. These initial results show that TSOM-determined cross-sectional (3-D) shape differences of 30?nm–40?nm wide lines agree well with critical-dimension atomic force microscope measurements. The TSOM method showed a linewidth uncertainty of 1.22?nm (k?=?2). Complex optical simulations are not needed for analysis using the TSOM method, making the process simple, economical, fast, and ideally suited for high volume nanomanufacturing process monitoring.

  18. Atomically localized plasmon enhancement in monolayer graphene

    E-Print Network [OSTI]

    Pennycook, Steve

    Atomically localized plasmon enhancement in monolayer graphene Wu Zhou1,2 *, Jaekwang Lee1,2 , Jagjit Nanda2 , Sokrates T. Pantelides1,2 , Stephen J. Pennycook1,2 and Juan-Carlos Idrobo1,2 * Plasmons plas- mons in very small regions could have applications in optoelec- tronics8,9 , plasmonics10

  19. Danish Atomic Energy Commission Research Establishment Riso

    E-Print Network [OSTI]

    roquott frem: Library of tho DmMi Atomic Enorgy Commlwton (AtornonorglkomrniMtonwM BtoHotok), RioA, DK, impregnated with four types of plastic, poly(methylmethacrylate), polyCstyrene/acrylonitril), polyester twice as much as conventional Danish face Btrip parquet flooring. Available on request from the Library

  20. Spectroscopic measurement of an atomic wave function

    E-Print Network [OSTI]

    Kapale, KT; Qamar, S.; Zubairy, M. Suhail.

    2003-01-01T23:59:59.000Z

    classical standing light, yields information about the position and momentum distribution of the atom [A. M. Herkommer, W. P. Schleich, and M. S. Zubairy, J. Mod. Opt. 44, 2507 (1997)]. In this paper, we show that both the amplitude and phase information...