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1

Laser-Induced Breakdown Spectroscopy  

E-Print Network [OSTI]

LIBS-1 Laser-Induced Breakdown Spectroscopy LIBS ANALYSIS OF METAL SURFACES Last updated: June 17, 2014 #12;LIBS-2 Laser­Induced Breakdown Spectroscopy (LIBS) LIBS ANALYSIS OF METAL SURFACES of species at a distance or in hard­to­reach or hazardous environments. Laser­Induced Breakdown Spectroscopy

Nizkorodov, Sergey

2

Double pulse laser induced breakdown spectroscopy; experimental study of  

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

Double pulse laser induced breakdown spectroscopy; experimental study of Double pulse laser induced breakdown spectroscopy; experimental study of lead emission intensity dependence on the wavelengths and sample matrix Title Double pulse laser induced breakdown spectroscopy; experimental study of lead emission intensity dependence on the wavelengths and sample matrix Publication Type Journal Article Year of Publication 2009 Authors Piscitelli, Vincent, Mauro A. Martinez, Alberto J. Fernandez, Jhanis J. Gonzalez, Xianglei Mao, and Richard E. Russo Journal Spectrochimica Acta Part B Volume 64 Issue 2 Pagination 147-154 Date Published 02/2009 Keywords Double pulse LIBS, laser induced breakdown spectroscopy, lead Abstract Lead (Pb) emission intensity (atomic line 405.78 nm) dependence on the sample matrix (metal alloy) was studied by means of collinear double pulse (DP)-laser induced breakdown spectroscopy (LIBS). The measurement of the emission intensity produced by three different wavelength combinations (i.e. I:532 nm-II:1064 nm, I:532 nm-II:532 nm, and I:532 nm-II:355 nm) from three series of standard reference materials showed that the lead atomic line 405.78 nm emission intensity was dependent on the sample matrix for all the combination of wavelengths, however reduced dependency was found for the wavelength combination I:532 nm-II:355 nm.

3

Ultrafast laser induced breakdown spectroscopy of electrode/electrolyte  

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

Ultrafast laser induced breakdown spectroscopy of electrode/electrolyte Ultrafast laser induced breakdown spectroscopy of electrode/electrolyte interfaces Title Ultrafast laser induced breakdown spectroscopy of electrode/electrolyte interfaces Publication Type Journal Article Year of Publication 2012 Authors Zormpa, Vasileia, Jaroslaw Syzdek, Xianglei Mao, Richard E. Russo, and Robert Kostecki Journal Applied Physics Letters Volume 100 Issue 23 Date Published 05-2012 ISSN 0003-6951 Keywords electrochemical electrodes, graphite, high-speed optical techniques, laser beam effects, organic compounds, pyrolysis, solid electrolytes Abstract Direct chemical analysis of electrode/electrolyte interfaces can provide critical information on surface phenomena that define and control the performance of Li-based battery systems. In this work, we introduce the use of ex situ femtosecond laser induced breakdown spectroscopy to probe compositional variations within the solid electrolyte interphase (SEI) layer. Nanometer-scale depth resolution was achieved for elemental and molecular depth profiling of SEI layers formed on highly oriented pyrolytic graphite electrodes in an organic carbonate-based electrolyte. This work demonstrates the unique ability of ultrafast laser spectroscopy as a highly versatile, light element-sensitive technique for direct chemical analysis of interfacial layers in electrochemical energy storage systems.

4

Laser Induced Breakdown Spectroscopy to Detect Copper Contamination in Transformer Insulation  

Science Journals Connector (OSTI)

Laser Induced Breakdown Spectroscopy combined with a laser-ablation based depth profiling technique is demonstrated for the detection of copper contamination in transformer insulation....

Aparna, N; Wazeem, M A; Vasa, Nilesh J; Sarathi, R; Sundara Rajan, J

5

Extracting Coal Ash Content from Laser-Induced Breakdown Spectroscopy (LIBS) Spectra by Multivariate Analysis  

Science Journals Connector (OSTI)

Laser-induced breakdown spectroscopy (LIBS) combined with partial least squares (PLS) analysis has been applied for the quantitative analysis of the ash content of coal in this...

Yao, Shunchun; Lu, Jidong; Dong, Meirong; Chen, Kai; Li, Junyan; Li, Jun

2011-01-01T23:59:59.000Z

6

Laser-induced breakdown spectroscopy (LIBS): a new spectrochemical technique  

SciTech Connect (OSTI)

We have used the breakdown spark from a focused laser beam to generate analytically useful emission spectra of minor constituents in air and other carrier gases. The medium was sampled directly. It was not necessary to reduce the sample to solution nor to introduce electrodes. The apparatus is particularly simple; a pulsed laser, spectrometer, and some method for time resolution. The latter is essential in laser-induced-breakdown spectroscopy (LIBS) because of the strong early continuum. High temperatures in the spark result in vaporization of small particles, dissociation of molecules, and excitation of atomic and ionic spectra, including species which are normally difficult to detect. In one application, we have monitored beryllium in air at conventrations below 1 ..mu..g/m/sup 3/, which is below 1 ppB (w/w). In another we have monitored chlorine and fluorine atoms in real time. LIBS has the potential for real-time direct sampling of contaminants in situ.

Radziemski, L.J.; Loree, T.R.; Cremers, D.A.

1982-01-01T23:59:59.000Z

7

Apparatus, system, and method for laser-induced breakdown spectroscopy  

DOE Patents [OSTI]

In laser-induced breakdown spectroscopy (LIBS), an apparatus includes a pulsed laser configured to generate a pulsed laser signal toward a sample, a constructive interference object and an optical element, each located in a path of light from the sample. The constructive interference object is configured to generate constructive interference patterns of the light. The optical element is configured to disperse the light. A LIBS system includes a first and a second optical element, and a data acquisition module. The data acquisition module is configured to determine an isotope measurement based, at least in part, on light received by an image sensor from the first and second optical elements. A method for performing LIBS includes generating a pulsed laser on a sample to generate light from a plasma, generating constructive interference patterns of the light, and dispersing the light into a plurality of wavelengths.

Effenberger, Jr., Andrew J; Scott, Jill R; McJunkin, Timothy R

2014-11-18T23:59:59.000Z

8

Titanium monoxide spectroscopy following laser-induced optical breakdown  

SciTech Connect (OSTI)

This work investigates Titanium Monoxide (TiO) in ablation-plasma by employing laser-induced breakdown spectroscopy (LIBS) with 1 to 10 TW/cm{sup 2} irradiance, pulsed, 13 nanosecond, Q-switched Nd:YAG laser radiation at the fundamental wavelength of 1064 nm. The analysis of TiO is based on our first accurate determination of transition line strengths for selected TiO A-X, B-X, and E-X transitions, particularly TiO A-X {gamma} and B-X {gamma} Prime bands. Electric dipole line strengths for the A{sup 3}{Phi}-X{sup 3}{delta} and B{sup 3}{Pi}-X{sup 3}{delta} bands of TiO are computed. The molecular TiO spectra are observed subsequent to laser-induced breakdown (LIB). We discuss analysis of diatomic molecular spectra that may occur simultaneously with spectra originating from atomic species. Gated detection is applied to investigate the development in time of the emission spectra following LIB. Collected emission spectra allow one to infer micro-plasma parameters such as temperature and electron density. Insight into the state of the micro-plasma is gained by comparing measurements with predictions of atomic and molecular spectra. Nonlinear fitting of recorded and computed diatomic spectra provides the basis for molecular diagnostics, while atomic species may overlap and are simultaneously identified. Molecular diagnostic approaches similar to TiO have been performed for diatomic molecules such as AlO, C{sub 2}, CN, CH, N{sub 2}, NH, NO and OH.

Parigger, Christian G.; Woods, Alexander C.; Keszler, Anna; Nemes, Laszlo; Hornkohl, James O. [The University of Tennessee/UT Space Institute, Center for Laser Applications, 411 B.H. Goethert Parkway, Tullahoma, TN 37388-9700 (United States); Chemical Research Center of the Hungarian Academy of Sciences, Institute of Materials and Environmental Chemistry, Pusztaszeri ut 59-67, H-1025 Budapest (Hungary); Chemical Research Center of the Hungarian Academy of Sciences, Laser Spectroscopy Laboratory, Pusztaszeri ut 59-67, H-1025 Budapest (Hungary); Hornkohl Consulting, Tullahoma, TN 37388 (United States)

2012-07-30T23:59:59.000Z

9

Development of laser induced breakdown spectroscopy instrumentatin for safeguards applications  

SciTech Connect (OSTI)

In September 2006, a Technical Meeting on Application of Laser Spectrometry Techniques in IAEA Safeguards was held at IAEA headquarters (HQ). One of the principal recommendations from this meeting was the need to 'pursue the development of novel complementary access instrumentation based on laser induced breakdown spectroscopy (LIBS) for the detection of gaseous and solid signatures and indicators of nuclear fuel cycle processes and associated materials.' Pursuant to this recommendation the Department of Safeguards (SG) under the Division of Technical Support (SGTS) convened the Experts and Users Advisory Meeting on Laser Induced Breakdown Spectroscopy (LIBS) for Safeguards Applications. This meeting was held at IAEA HQ from July 7-11,2008 and hosted by the Novel Technologies Unit (NTU). The meeting was attended by 12 LIBS experts from the Czech Republic, the European Commission, France, the Republic of Korea, the United States of America, Germany, the United Kingdom of Great Britain, Canada, and Northern Ireland. After a presentation of the needs of the IAEA inspectors, the LIBS experts were in agreement that needs as presented could be partially or fully fulfilled using LIBS instrumentation. The needs of the IAEA inspectors were grouped in the following broad categories: (1) Improvements to in-field measurements/environmental sampling; (2) Monitoring status of activity in a Hot Cell; (3) Verifying status of activity at a declared facility via process monitoring; and (4) Need for pre-screening of environmental samples before analysis. Under the Department of Energy/National Nuclear Security Administration (DOE/NNSA) Next Generation Safeguards Initiative (NGSI) Los Alamos National Laboratory is exploring three potential applications of LIBS for international safeguards. As part of this work, we are developing: (1) a user-friendly man-portable LIBS system to characterize samples across a wide range of elements in the periodic table from hydrogen up to heavy elements like plutonium and uranium; (2) a LIBS system that can be deployed in harsh environments such as gloveboxes and hot cells providing relative compositional analysis of process streams for example ratios like Cm/Pu and Cm/U; and (3) an inspector field deployable system that can be used to analyze the elemental composition of microscopic quantities of samples containing plutonium and uranium. In this paper we will describe our current development and performance testing results both in a fixed lab and measurements in field deployable configurations using LIBS instrumentation developed for applications to international safeguards.

Barefield Il, James E [Los Alamos National Laboratory; Clegg, Samuel M [Los Alamos National Laboratory; Le, Loan A [Los Alamos National Laboratory; Lopez, Leon N [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

10

Elemental analysis of cotton by laser-induced breakdown spectroscopy  

SciTech Connect (OSTI)

Laser-induced breakdown spectroscopy (LIBS) has been applied to the elemental characterization of unprocessed cotton. This research is important in forensic and fraud detection applications to establish an elemental fingerprint of U.S. cotton by region, which can be used to determine the source of the cotton. To the best of our knowledge, this is the first report of a LIBS method for the elemental analysis of cotton. The experimental setup consists of a Nd:YAG laser that operates at the fundamental wavelength as the LIBS excitation source and an echelle spectrometer equipped with an intensified CCD camera. The relative concentrations of elements Al, Ba, Ca, Cr, Cu, Fe, Mg, and Sr from both nutrients and environmental contributions were determined by LIBS. Principal component analysis was used to visualize the differences between cotton samples based on the elemental composition by region in the U.S. Linear discriminant analysis of the LIBS data resulted in the correct classification of >97% of the cotton samples by U.S. region and >81% correct classification by state of origin.

Schenk, Emily R.; Almirall, Jose R.

2010-05-01T23:59:59.000Z

11

Glass-batch composition monitoring by laser-induced breakdown spectroscopy  

Science Journals Connector (OSTI)

Laser-induced breakdown spectroscopy is an almost ideal technique for the in situ monitoring of the composition of a glass batch before it enters the glass-melting furnace, saving a...

Lal, Bansi; Yueh, Fang-Yu; Singh, Jagdish P

2005-01-01T23:59:59.000Z

12

On-Line Sorting of Wood Treated with Chromated Copper Arsenate Using Laser-Induced Breakdown Spectroscopy  

Science Journals Connector (OSTI)

This paper details the design, implementation, and field evaluation of an online detector system using laser-induced breakdown spectroscopy (LIBS) for the analysis of copper...

Moskal, T M; Hahn, D W

2002-01-01T23:59:59.000Z

13

Laser-Induced Breakdown Spectroscopy System Using a Passively Q-Switched Laser  

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

Laser-Induced Breakdown Spectroscopy System Laser-Induced Breakdown Spectroscopy System Using a Passively Q-Switched Laser Opportunity Research is active on the patent-pending technology, titled "Laser-Induced Breakdown Spectroscopy (LIBS) System Using a Passively Q-Switched Laser." This technology is available for licensing and/or further collaborative research from the U.S. Department of Energy's National Energy Technology Laboratory. Overview Atomic spectroscopy systems such as LIBS are used in many applications where the elemental composition of a solid, liquid or gas sample is desired. In addition, this detection technology has the advantage of providing composition data without sample destruction. In LIBS systems, precise timing and control between the laser and the spectrometer detector are

14

Laser-Induced Breakdown Spectroscopy (LIBS) Analysis of Calcium Ions Dissolved in Water Using Filter Paper Substrates: An Ideal Internal Standard for Precision Improvement  

Science Journals Connector (OSTI)

We report an approach for selecting an internal standard to improve the precision of laser-induced breakdown spectroscopy (LIBS) analysis for determining calcium (Ca) concentration in...

Choi, Daewoong; Gong, Yongdeuk; Nam, Sang-Ho; Han, Song-Hee; Yoo, Jonghyun; Lee, Yonghoon

2014-01-01T23:59:59.000Z

15

Laser Ignition and Laser Induced Breakdown Spectroscopy in Engines Using Hollow Core Fiber Delivery  

Science Journals Connector (OSTI)

We describe the use of hollow core optical fibers to deliver laser sparks. The sparks are used to ignite engines and to enable air-to-fuel measurements by laser induced breakdown...

Joshi, Sachin; Yalin, Azer P; Dumitrescu, Cosmin; Olcmen, Semih; Puzinauskas, Paul

16

Temperature effect on laser-induced breakdown spectroscopy spectra of molten and solid salts  

SciTech Connect (OSTI)

Laser-induced breakdown spectroscopy (LIBS) has been investigated as a potential analytical tool to improve operations and safeguards for electrorefiners, such as those used in processing spent nuclear fuel. This study set out to better understand the effect of sample temperature and physical state on LIBS spectra of molten and solid salts by building calibration curves of cerium and assessing self-absorption, plasma temperature, electron density, and local thermal equilibrium (LTE). Samples were composed of a LiClKCl eutectic salt, an internal standard of MnCl2, and varying concentrations of CeCl3 (0.1, 0.3, 0.5, 0.8, and 1.0 wt.% Ce) under different temperatures (773, 723, 673, 623, and 573 K). Analysis of salts in their molten form is preferred as plasma plumes from molten samples experienced less self-absorption, less variability in plasma temperature, and higher clearance of the minimum electron density required for local thermal equilibrium. These differences are attributed to plasma dynamics as a result of phase changes. Spectral reproducibility was also better in the molten state due to sample homogeneity.

Cynthia Hanson; Supathorn Phongikaroon; Jill R. Scott

2014-07-01T23:59:59.000Z

17

Laboratory feasibility study of fusion vessel inner wall chemical analysis by Laser Induced Breakdown Spectroscopy  

Science Journals Connector (OSTI)

Laser Induced Breakdown Spectroscopy (LIBS) is nowadays a well established tool for qualitative, semi-quantitative and quantitative analyses of surfaces, with micro-destructive characteristics and capabilities for stratigraphy. LIBS is an appealing technique compared with many other types of elemental analysis thanks to the set up versatility facilitating non-invasive and remote analyses, as well as suitability to diagnostics in harsh environments. In this work, LIBS capabilities were used for the determination of the atomic composition of multilayered samples simulating the tiles of plasma facing components in the next generation fusion machines such as ITER. A new experimental setup was designed and realized in order to optimize the characteristics of an LIBS system working at low pressure and remotely, as it should be for an in situ system to be applied in monitoring the erosion and redeposition phenomena occurring on the inner walls of a fusion device. The effects of time delay and laser fluence on LIBS sensitivity at reduced pressure were examined, looking for operational conditions suitable to analytical applications. The quantitative analysis of some atomic species in the superficial layer has been carried out using a Calibration Free (CF) approach in the time window where Local Thermal Equilibrium (LTE) was assumed for an LIBS analysis.

Salvatore Almaviva; Luisa Caneve; Francesco Colao; Roberta Fantoni; Giorgio Maddaluno

2012-01-01T23:59:59.000Z

18

Total Carbon Measurement in Soils Using Laser-Induced Breakdown Spectroscopy: Results from the Field and Implications for Carbon Sequestration  

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

Total Carbon Measurement in Soils using Laser-Induced Breakdown Total Carbon Measurement in Soils using Laser-Induced Breakdown Spectroscopy: Results from the Field and Implications for Carbon Sequestration Michael H. Ebinger (mhe@lanl.gov, 505-667-3147) Environmental Dynamics and Spatial Analysis Group (EES-10), MS J495 Earth and Environmental Sciences Division Los Alamos National Laboratory, Los Alamos, NM 87545, USA. David A. Cremers (cremers_david@lanl.gov, 505-665-4180) Advanced Chemical Diagnostics and Instrumentation Group, MS J565 Chemistry Division Los Alamos National Laboratory, Los Alamos, NM 87545 David D. Breshears (daveb@lanl.gov, 505-665-2803) Environmental Dynamics and Spatial Analysis Group (EES-10), MS J495 Earth and Environmental Sciences Division Los Alamos National Laboratory, Los Alamos, NM 87545, USA.

19

Elemental analysis by microwave-assisted laser-induced breakdown spectroscopy: Evaluation on ceramics  

E-Print Network [OSTI]

,2 These sources are usually flames or plasmas: arcs, sparks, plasma jets, inductively coupled plasma (ICP), high demonstrated the signal enhancement ability of their LAMPS (Laser-Assisted Microwave Plasma Spectroscopy utilizing interaction between microwave radiation and laser-induced plasma has been evaluated. Experimental

Richardson, Martin C.

20

Identification of vapor-phase chemical warfare agent simulants and rocket fuels using laser-induced breakdown spectroscopy  

SciTech Connect (OSTI)

Application of laser-induced breakdown spectroscopy (LIBS) to the identification of security threats is a growing area of research. This work presents LIBS spectra of vapor-phase chemical warfare agent simulants and typical rocket fuels. A large dataset of spectra was acquired using a variety of gas mixtures and background pressures and processed using partial least squares analysis. The five compounds studied were identified with a 99% success rate by the best method. The temporal behavior of the emission lines as a function of chamber pressure and gas mixture was also investigated, revealing some interesting trends that merit further study.

Stearns, Jaime A.; McElman, Sarah E.; Dodd, James A.

2010-05-01T23:59:59.000Z

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


21

The application of spectrum standardization method for carbon analysis in coal using laser-induced breakdown spectroscopy  

E-Print Network [OSTI]

Measurements of carbon content in coal using laser-induced breakdown spectroscopy (LIBS) is limited by its low measurement precision and accuracy. A spectrum standardization method was proposed to achieve both reproducible and accurate results for the quantitative analysis of carbon content in coal with LIBS. The proposed method utilized the molecular carbon emissions to compensate the diminution of atomic carbon emission caused by matrix effect. The compensated carbon line intensities were further converted into an assumed standard state with fixed plasma temperature, electron density, and total number density of elemental carbon, which is proportional to its concentration in the coal samples. In addition, in order to obtained better compensation for total carbon number density fluctuations, an iterative algorithm was applied, which is different from our previous standardization calculations. The modified spectrum standardization model was applied to the measurement of carbon content in 24 bituminous coal sa...

Li, Xiongwei; Fu, Yangting; Li, Zheng; Liu, Jianming; Ni, Weidou

2014-01-01T23:59:59.000Z

22

,* Copper transport and accumulation in spruce stems (picea abies(L.) Karsten) revelaed by laser-induced breakdown spectroscopy  

SciTech Connect (OSTI)

Laser-Induced Breakdown Spectroscopy (LIBS) in double pulse configuration (DP LIBS) was used for scanning elemental spatial distribution in annual terminal stems of spruce (Picea abies (L.) Karsten). Cross sections of stems cultivated in Cu2+ solution of different concentrations were prepared and analyzed by DP LIBS. Raster scanning with 150 m spatial resolution was set and 2D (2-dimentional) maps of Cu and Ca distribution were created on the basis of the data obtained. Stem parts originating in the vicinity of the implementation of the cross sections were mineralized and subsequently Cu and Ca contents were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results provide quantitative information about overall concentration of the elements in places, where LIBS measurements were performed. The fluorescence pictures were created to compare LIBS distribution maps and the fluorescence intensity (or the increase in autofluorescence) was used for the comparison of ICP-MS quantitative results. Results from these three methods can be utilized for quantitative measurements of copper ions transport in different plant compartments in dependence on the concentration of cultivation medium and/or the time of cultivation.

Krajcarova, Dr. Lucie [Czech Technical University; Novotny, Dr. Karel [Mendel University of Brno; Babula, Dr. Petr [Czech Technical University; Pravaznik, Dr Ivo [Czech Technical University; Kucerova, Dr. Petra [Czech Technical University; Vojtech, Dr. Adam [Czech Technical University; Martin, Madhavi Z [ORNL; Kizek, Dr. Rene [Czech Technical University; Kaiser, Jozef [ORNL

2013-01-01T23:59:59.000Z

23

Methods for measurement of heterogeneous materials with laser-induced breakdown spectroscopy (LIBS)  

E-Print Network [OSTI]

2000. 15) Welz B, Atomic Absorption Spectrometry, ThirdFor elemental analyses atomic absorption spectroscopy iscommonly used (15). Atomic absorption spectroscopy works by

Effenberger, Andrew Jay

2009-01-01T23:59:59.000Z

24

Quantitative hydrogen analysis of zircaloy-4 in laser-induced breakdown spectroscopy with ambient helium gas  

Science Journals Connector (OSTI)

This experiment was carried out to address the need for overcoming the difficulties encountered in hydrogen analysis by means of plasma emission spectroscopy in atmospheric ambient...

Ramli, Muliadi; Fukumoto, Ken-ichi; Niki, Hideaki; Abdulmadjid, Syahrun Nur; Idris, Nasrullah; Maruyama, Tadashi; Kagawa, Kiichiro; Tjia, May On; Pardede, Marincan; Kurniawan, Koo Hendrik; Hedwig, Rinda; Lie, Zener Sukra; Lie, Tjung Jie; Kurniawan, Davy Putra

2007-01-01T23:59:59.000Z

25

A model combining spectrum standardization and dominant factor based partial least square method for carbon analysis in coal by laser-induced breakdown spectroscopy  

E-Print Network [OSTI]

Successful quantitative measurement of carbon content in coal using laser-induced breakdown spectroscopy (LIBS) is suffered from relatively low precision and accuracy. In the present work, the spectrum standardization method was combined with the dominant factor based partial least square (PLS) method to improve the measurement accuracy of carbon content in coal by LIBS. The combination model employed the spectrum standardization method to convert the carbon line intensity into standard state for more accurately calculating the dominant carbon concentration, and then applied PLS with full spectrum information to correct the residual errors. The combination model was applied to the measurement of carbon content for 24 bituminous coal samples. The results demonstrated that the combination model could further improve the measurement accuracy compared with both our previously established spectrum standardization model and dominant factor based PLS model using spectral area normalized intensity for the dominant fa...

Li, Xiongwei; Fu, Yangting; Li, Zheng; Ni, Weidou

2014-01-01T23:59:59.000Z

26

Design of a laser-induced breakdown spectroscopy system for on-line quality analysis of pulverized coal in power plants  

SciTech Connect (OSTI)

It is vitally important for a power plant to determine the chemical composition of coal prior to combustion in order to obtain optimal boiler control. In this work, a fully software-controlled laser-induced breakdown spectroscopy (LIBS) system comprising a LIBS apparatus and sampling equipment has been designed for possible application to power plants for on-line quality analysis of pulverized coal. Special attention was given to the LIBS system, the data processing methods (especially the normalization with Bode Rule/DC Level) and the specific settings (the software-controlled triggering source, high-pressure gas cleaning device, sample preparation module, sampling module, etc.), which gave the best direct measurement for C, H, Si, Na, Mg, Fe, Al, and Ti with measurement errors less than 10% for pulverized coal. Therefore, the apparatus is accurate enough to be applied to industries for on-line monitoring of pulverized coal. The method of proximate analysis was also introduced and the experimental error of A(ad) (Ash, 'ad' is an abbreviation for 'air dried') was shown in the range of 2.29 to 13.47%. The programmable logic controller (PLC) controlled on-line coal sampling equipment, which is designed based upon aerodynamics, and is capable of performing multipoint sampling and sample-preparation operation.

Yin, W.B.; Zhang, L.; Dong, L.; Ma, W.G.; Jia, S.T. [Shanxi Agricultural University, Taiyuan (China)

2009-08-15T23:59:59.000Z

27

Procedure for calibration of a portable, real-time beryllium aerosol monitor based on laser-induced breakdown spectroscopy  

E-Print Network [OSTI]

Spectroscopy (LIPS), is an analytical method whereby atmospheric components and contaminants may be analyzed in real-time or near real-time directly in the workplace. A transportable beryllium air monitor system based on LIBS has been developed at the Los...

Killough, David Thomas

2012-06-07T23:59:59.000Z

28

E-Print Network 3.0 - all-fiber-coupled laser-induced breakdown...  

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

coupled laser-induced breakdown Search Powered by Explorit Topic List Advanced Search Sample search results for: all-fiber-coupled laser-induced breakdown Page: << < 1 2 3 4 5 > >>...

29

Quantitative laser-induced breakdown spectroscopy data using peak area step-wise regression analysis: an alternative method for interpretation of Mars science laboratory results  

SciTech Connect (OSTI)

The ChemCam instrument on the Mars Science Laboratory (MSL) will include a laser-induced breakdown spectrometer (LIBS) to quantify major and minor elemental compositions. The traditional analytical chemistry approach to calibration curves for these data regresses a single diagnostic peak area against concentration for each element. This approach contrasts with a new multivariate method in which elemental concentrations are predicted by step-wise multiple regression analysis based on areas of a specific set of diagnostic peaks for each element. The method is tested on LIBS data from igneous and metamorphosed rocks. Between 4 and 13 partial regression coefficients are needed to describe each elemental abundance accurately (i.e., with a regression line of R{sup 2} > 0.9995 for the relationship between predicted and measured elemental concentration) for all major and minor elements studied. Validation plots suggest that the method is limited at present by the small data set, and will work best for prediction of concentration when a wide variety of compositions and rock types has been analyzed.

Clegg, Samuel M [Los Alamos National Laboratory; Barefield, James E [Los Alamos National Laboratory; Wiens, Roger C [Los Alamos National Laboratory; Dyar, Melinda D [MT HOLYOKE COLLEGE; Schafer, Martha W [LSU; Tucker, Jonathan M [MT HOLYOKE COLLEGE

2008-01-01T23:59:59.000Z

30

Visualization of laser-induced breakdown and Ying-Ling Chen and J. W. L. Lewis  

E-Print Network [OSTI]

Visualization of laser-induced breakdown and ignition Ying-Ling Chen and J. W. L. Lewis Center, Tennessee 37388-8897 ychen@utsi.edu, jlewis@utsi.edu Abstract: Laser-induced gas breakdown and ignition-going simulation modeling of laser-ignition. © 2001 Optical Society of American OCIS codes: (140.3440) Laser

Davis, Lloyd M.

31

Preliminary Design of Laser - induced Breakd own Spectroscopy for Proto - MPEX  

SciTech Connect (OSTI)

Laser-induced breakdown spectroscopy (LIBS) is a technique for measuring surface matter composition. LIBS is performed by focusing laser radiation onto a target surface, ablating the surface, forming a plasma, and analyzing the light produced. LIBS surface analysis is a possible diagnostic for characterizing plasma-facing materials in ITER. Oak Ridge National Laboratory (ORNL) has enabled the initial installation of a laser-induced breakdown spectroscopy diagnostic on the prototype Material-Plasma Exposure eXperiment (Proto-MPEX), which strives to mimic the conditions found at the surface of the ITER divertor. This paper will discuss the LIBS implementation on Proto-MPEX, preliminary design of the fiber optic LIBS collection probe, and the expected results.

Shaw, Guinevere C [ORNL] [ORNL; Biewer, T.M. [Oak Ridge National Laboratory (ORNL)] [Oak Ridge National Laboratory (ORNL); Martin, Madhavi Z [ORNL] [ORNL; Martin, Rodger Carl [ORNL] [ORNL

2014-01-01T23:59:59.000Z

32

Optical breakdown threshold investigation of 1064 nm laser induced air plasmas  

SciTech Connect (OSTI)

We present the theoretical and experimental measurements and analysis of the optical breakdown threshold for dry air by 1064 nm infrared laser radiation and the significance of the multiphoton and collisional cascade ionization process on the breakdown threshold measurements over pressures range from 10 to 2000 Torr. Theoretical estimates of the breakdown threshold laser intensities and electric fields are obtained using two distinct theories namely multiphoton and collisional cascade ionization theories. The theoretical estimates are validated by experimental measurements and analysis of laser induced breakdown processes in dry air at a wavelength of 1064 nm by focusing 450 mJ max, 6 ns, 75 MW max high-power 1064 nm IR laser radiation onto a 20 {mu}m radius spot size that produces laser intensities up to 3 - 6 TW/cm{sup 2}, sufficient for air ionization over the pressures of interest ranging from 10 to 2000 Torr. Analysis of the measured breakdown threshold laser intensities and electric fields are carried out in relation with classical and quantum theoretical ionization processes, operating pressures. Comparative analysis of the laser air breakdown results at 1064 nm with corresponding results of a shorter laser wavelength (193 nm) [M. Thiyagarajan and J. E. Scharer, IEEE Trans. Plasma Sci. 36, 2512 (2008)] and a longer microwave wavelength (10{sup 8} nm) [A. D. MacDonald, Microwave Breakdown in Gases (Wiley, New York, 1966)]. A universal scaling analysis of the breakdown threshold measurements provided a direct comparison of breakdown threshold values over a wide range of frequencies ranging from microwave to ultraviolet frequencies. Comparison of 1064 nm laser induced effective field intensities for air breakdown measurements with data calculated based on the collisional cascade and multiphoton breakdown theories is used successfully to determine the scaled collisional microwave portion. The measured breakdown threshold of 1064 nm laser intensities are then scaled to classical microwave breakdown theory after correcting for the multiphoton ionization process for different pressures and good agreement, regarding both pressure dependence and breakdown threshold electric fields, is obtained. The effect of the presence of submicron particles on the 1064 nm breakdown threshold was also investigated. The measurements show that higher breakdown field is required, especially at lower pressures, and in close agreement with classical microwave breakdown theory and measurements in air.

Thiyagarajan, Magesh; Thompson, Shane [Plasma Engineering Research Lab (PERL), College of Science and Engineering, Texas A and M University-Corpus Christi, Texas 78412 (United States)

2012-04-01T23:59:59.000Z

33

Applications of laser-induced gratings to spectroscopy and dynamics  

SciTech Connect (OSTI)

This program has traditionally emphasized two principal areas of research. The first is the spectroscopic characterization of large-amplitude motion on the ground-state potential surface of small, transient molecules. The second is the reactivity of carbonaceous clusters and its relevance to soot and fullerene formation in combustion. Motivated initially by the desire to find improved methods of obtaining stimulated emission pumping (SEP) spectra of transients, most of our recent work has centered on the use of laser-induced gratings or resonant four-wave mixing in free-jet expansions. These techniques show great promise for several chemical applications, including molecular spectroscopy and photodissociation dynamics. The author describes recent applications of two-color laser-induced grating spectroscopy (LIGS) to obtain background-free SEP spectra of transients and double resonance spectra of nonfluorescing species, and the use of photofragment transient gratings to probe photodissociation dynamics.

Rohlfing, E.A. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01T23:59:59.000Z

34

ChemCam on MSL 2009: first laser induced breakdown spectrometer for space science  

SciTech Connect (OSTI)

ChemCam is one of the 10 instrument suites on the Mars Science Laboratory, a martian rover being built by Jet Propulsion Laboratory, for the next NASA mission to Mars (MSL 2009). ChemCam is an instrument package consisting of two remote sensing instruments: a Laser-Induced Breakdown Spectrometer (LIBS) and a Remote Micro-Imager (RMI). LIBS provides elemental compositions of rocks and soils, while the RMI places the LIBS analyses in their geomorphologic context. Both instruments rely on an autofocus capability to precisely focus on the chosen target, located at distances from the rover comprised between 1 and 9 m for LIBS, and 2 m and infinity for RMI. ChemCam will help determine which samples, within the vicinity of the MSL rover, are of sufficient interest to use the contact and in-situ instruments for further characterization. It will provide valuable analyses of samples that are inaccessible to contact and in-situ instruments, and of a much larger number of samples than can be done with this kind of instrument. ChemCam also has a capability to provide passive spectroscopy data of rocks and soils on Mars. ChemCam hardware consists of a Mast Unit (MU), provided by France, and a Body Unit (BU) built and tested in the USA. The Flight Model of the MU is assembled, tested and now available in the USA, while the BU is currently being assembled and tested. Both will be connected by the end of year '08 for end-to-end functional and performance tests, before delivery to JPL and assembly on the MSL rover. Launch is scheduled for October 09. After describing the concept of ChemCam, this presentation focuses on its French part, Mast Unit. The results presented show that Mast Unit is able to generate a plasma and collect its light, over the full applicable ranges of distances and temperatures on Mars.

Wiens, Roger C [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

35

Plasma spectroscopy of H, Li, and Na in plumes resulting from laser-induced droplet explosion  

Science Journals Connector (OSTI)

The plasma emission resulting from laser-induced breakdown of large transparent H2O droplets (with and without NaCl or LiCl) has been spectrally and spatially resolved along...

Eickmans, Johannes H; Hsieh, Wen-Feng; Chang, Richard K

1987-01-01T23:59:59.000Z

36

Laser Induced Breakdown Spectroscopy and Applications Toward Thin Film Analysis  

E-Print Network [OSTI]

1.5 Laserb) 60 shots, (c) 80 shots, and (d) 100 shots with 60mJ laserAutofocusing . . . . . . . . . . 2.4 Laser and Spectrometer

Owens, Travis Nathan

2011-01-01T23:59:59.000Z

37

Aerosol measurements with laser-induced breakdown spectroscopy  

E-Print Network [OSTI]

monitoring with an atmospheric microwave-plasma having aMonitoring with an Atmospheric Microwave-Plasma Having abased on an atmospheric microwave plasma are underway by

Lithgow, Gregg Arthur

2007-01-01T23:59:59.000Z

38

Aerosol measurements with laser-induced breakdown spectroscopy  

E-Print Network [OSTI]

fused silica lenses to focus the plasma emission onto a UVideal lens focuses light from the plasma onto the tip of anboth focus the laser pulse and collect the plasma emission

Lithgow, Gregg Arthur

2007-01-01T23:59:59.000Z

39

Ignition characteristics of methane/air premixed mixture by microwave-enhanced laser-induced breakdown plasma  

Science Journals Connector (OSTI)

A microwave-enhanced plasma generation technique was combined with laser-induced ignition to improve ignition characteristics. A locally intensified microwave field was formed near the...

Nishiyama, Atsushi; Moon, Ahsa; Ikeda, Yuji; Hayashi, Jun; Akamatsu, Fumiteru

2013-01-01T23:59:59.000Z

40

High resolution laser induced fluorescence Doppler velocimetry utilizing saturated absorption spectroscopy  

SciTech Connect (OSTI)

A high resolution laser induced fluorescence (LIF) system has been developed to measure the flow velocity field of neutral particles in an electron-cyclotron-resonance argon plasma. The flow velocity has been determined by the Doppler shift of the LIF spectrum, which is proportional to the velocity distribution function. Very high accuracy in velocity determination has been achieved by installing a saturated absorption spectroscopy unit into the LIF system, where the absolute value and scale of laser wavelength are determined by using the Lamb dip and the fringes of a Fabry-Perot interferometer. The minimum detectable flow velocity of a newly developed LIF system is {+-}2 m/s, and this performance remains unchanged in a long-time experiment. From the radial measurements of LIF spectra of argon metastable atoms, it is found that there exists an inward flow of neutral particles associated with neutral depletion.

Aramaki, Mitsutoshi [Department of Electrical Engineering and Computer Science, Nagoya University, Nagoya 464-8603 (Japan); Ogiwara, Kohei; Etoh, Shuzo [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga 816-8580 (Japan); Yoshimura, Shinji [National Institute for Fusion Science, Toki 509-5292 (Japan); Tanaka, Masayoshi Y. [Department of Advanced Energy Engineering Science, Kyushu University, Kasuga 816-8580 (Japan)

2009-05-15T23:59:59.000Z

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


41

An improved approach for hydrogen analysis in metal samples using single laser-induced gas plasma and target plasma at helium atmospheric pressure  

Science Journals Connector (OSTI)

We report in this paper the results of an experimental study on hydrogen analysis of solid samples in high pressure helium ambient gas employing the basic scheme of laser induced breakdown spectroscopy (LIBS)....

S.N. Abdulmadjid; M.M. Suliyanti; K.H. Kurniawan; T.J. Lie; M. Pardede

2006-01-01T23:59:59.000Z

42

Differential laser absorption spectroscopy of uranium in an atmospheric pressure laser-induced plasma  

Science Journals Connector (OSTI)

A two-beam differential laser absorption technique is used to measure U238 absorption spectra with high signal-to-noise ratios in an atmospheric pressure laser-induced plasma....

Taylor, N R; Phillips, M C

2014-01-01T23:59:59.000Z

43

Concentration and temperature measurements in a laser-induced high explosive ignition zone. Part I: LIF spectroscopy measurements  

Science Journals Connector (OSTI)

This paper describes a method that combines a laser ignition technique with laser-induced fluorescence (LIF) spectroscopy for studying the gas-phase products in a laser-induced subignition zone and the reactions that lead to a self-sustained ignition. The experiment comprises a tunable 180 W CO2-laser as ignition source, an excimer pumped dye-laser for inducing the fluorescence, and a spectrometer equipped with an optical multichannel analyzer. This technique was used for measurements of relative NO and CN concentrations in the subignition zone of RDX (1,3,5-Trinitrohexahydro-s-triazine) in pseudo-real time (time resolution better than 1 ?s). By using LIF technique for measuring the relative population of different vibrational levels, we were able to calculate the vibrational temperature in the gas phase reaction zone in front of the sample at subignition to approximately 3100 K. The measurements show clearly that the chemical reactions and the diffusion in the subignition zone play an important part long before a self-sustained reaction occurs, and thus influence the sensitivity of an explosive. By using LIF imaging technique, two-dimensional images of the NO concentration were registered at different times in the ignition pulse, and the wavelength dependence of the ignition source was also studied. The results correspond to a model for fast radiative ignition where Lambert-Beer absorption is the main energy interaction mechanism between the energetic material and the laser beam.

H. stmark; M. Carlson; K. Ekvall

1996-01-01T23:59:59.000Z

44

Characterization of Laser-Induced Breakdown Spectroscopy (LIBS) for Application to Space Exploration  

Science Journals Connector (OSTI)

Early in the next century, several space missions are planned with the goal of landing craft on asteroids, comets, the Moon, and Mars. To increase the scientific return of these...

Knight, Andrew K; Scherbarth, Nancy L; Cremers, David A; Ferris, Monty J

2000-01-01T23:59:59.000Z

45

Surface Treatment Analyses of Car Bearings by Using Laser-Induced Breakdown Spectroscopy  

Science Journals Connector (OSTI)

Determination of surface coating composition is a problem of great importance for industry and production related to the quality control of products and processes. One of the most...

Alvira, F C; Orzi, D J O; Bilmes, G M

2009-01-01T23:59:59.000Z

46

Methods for measurement of heterogeneous materials with laser-induced breakdown spectroscopy (LIBS)  

E-Print Network [OSTI]

pulse-plasma coupling, sample heating and atmosphericaffect the plasma due to the change of the argon atmosphere.plasma is produced it expands into a less dense atmosphere

Effenberger, Andrew Jay

2009-01-01T23:59:59.000Z

47

Comparative study of femtosecond and nanosecond laser-induced breakdown spectroscopy of depleted uranium  

SciTech Connect (OSTI)

We present spectra of depleted uranium metal from laser plasmas generated by nanosecond Nd:YAG (1064 nm) and femtosecond Ti:sapphire (800 nm) laser pulses. The latter pulses produce short-lived and relatively cool plasmas in comparison to the longer pulses, and the spectra of neutral uranium atoms appear immediately after excitation. Evidence for nonequilibrium excitation with femtosecond pulses is found in the dependence of spectral line intensities on the pulse chirp.

Emmert, Luke A.; Chinni, Rosemarie C.; Cremers, David A.; Jones, C. Randy; Rudolph, Wolfgang

2011-01-20T23:59:59.000Z

48

Comparative study of femtosecond and nanosecond laser-induced breakdown spectroscopy of depleted uranium  

Science Journals Connector (OSTI)

We present spectra of depleted uranium metal from laser plasmas generated by nanosecond Nd:YAG (1064?nm) and femtosecond Ti:sapphire (800?nm) laser pulses. The latter pulses produce...

Emmert, Luke A; Chinni, Rosemarie C; Cremers, David A; Jones, C Randy; Rudolph, Wolfgang

2011-01-01T23:59:59.000Z

49

E-Print Network 3.0 - abnormal breakdown characteristic Sample...  

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

present the measurements and analysis of laser- induced breakdown processes in dry... -power microwave breakdown based on measured laser breakdown observations....

50

4D Density Determination of NH Radicals in an MSE Microplasma Combining Planar Laser Induced Fluorescence and Cavity Ring-Down Spectroscopy  

SciTech Connect (OSTI)

An application of microplasmas is surface modification under mild conditions and of small, well defined areas. For this, an understanding of the plasma composition is of importance. First results of our work on the production and detection of NH radicals in a capacitively coupled radio frequency (RF) microplasma are presented. A microstructured comb electrode was used to generate a glow discharge in a hydrogen/nitrogen gas mixture by applying 13.56 MHz RF voltage. The techniques of planar laser induced fluorescence (PLIF) and cavity ring-down spectroscopy (CRDS) are used for space and time resolved, quantitative detection of the NH radical in the plasma. The rotational temperature was determined to be 820 K and, the density 5.1x10{sup 12} cm{sup 3}. Also, time dependent behaviour of the NH production was observed.

Visser, Martin; Schenk, Andreas; Gericke, Karl-Heinz [Technische Universitaet Braunschweig, Institut fuer Physikalische und Theoretische Chemie Hans-Sommer-Str. 10, 38106 Braunschweig (Germany)

2010-10-13T23:59:59.000Z

51

Evaluation of Laser-Induced Breakdown Spectroscopy (LIBS) for Measurement of Silica on Filter Samples of Coal Dust  

Science Journals Connector (OSTI)

Airborne silica dust (quartz) is common in coal mines and represents a respiratory hazard that can lead to silicosis, a potentially fatal lung disease. With an eye toward developing a...

Stipe, Christopher B; Miller, Arthur L; Brown, Jonathan; Guevara, Edward; Cauda, Emanuele

2012-01-01T23:59:59.000Z

52

Experimental measurements of multiphoton enhanced air breakdown by a subthreshold intensity excimer laser  

E-Print Network [OSTI]

laser Jesse Way,a Jason Hummelt, and John Scharer Department of Electrical and Computer Engineering measurements of laser induced breakdown plasma in atmospheric air by subthreshold intensity 5.5 109 W/cm2 193 nm laser radiation. Using molecular spectroscopy and two-wavelength interferometry, it is shown

Scharer, John E.

53

Laser-induced ignition by optical breakdown  

Science Journals Connector (OSTI)

This paper is an experimental work of the applied methodical character in which as an attempt to optimize a laser ignition system a systematic study of the best incoupling geometry for the employed Nd:YAG laser w...

E. Schwarz; I. Muri; J. Tauer; H. Kofler; E. Wintner

2010-06-01T23:59:59.000Z

54

Early stage expansion and time-resolved spectral emission of laser-induced  

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

Early stage expansion and time-resolved spectral emission of laser-induced Early stage expansion and time-resolved spectral emission of laser-induced plasma from polymer Title Early stage expansion and time-resolved spectral emission of laser-induced plasma from polymer Publication Type Journal Article Year of Publication 2009 Authors Boueri, Myriam, Matthieu Baudelet, Jin Yu, Xianglei Mao, Samuel S. Mao, and Richard E. Russo Journal Applied Surface Science Volume 255 Issue 24 Pagination 9566-9571 Date Published 09/2009 Keywords Early stage plasma expansion, Laser ablation of polymer, Plasma spectral emission Abstract In the nanosecond laser ablation regime, absorption of laser energy by the plasma during its early stage expansion critically influences the properties of the plasma and thus its interaction with ambient air. These influences can significantly alter spectral emission of the plasma. For organic samples especially, recombination of the plasma with the ambient air leads to interfering emissions with respect to emissions due to native species evaporated from the sample. Distinguishing interfering emissions due to ambient air represents a critical issue for the application of laser-induced breakdown spectroscopy (LIBS) to the analysis of organic materials. In this paper, we report observations of early stage expansion and interaction with ambient air of the plasma induced on a typical organic sample (nylon) using timeresolved shadowgraph. We compare, in the nanosecond ablation regime, plasmas induced by infrared (IR) laser pulses (1064 nanometers) and ultraviolet (UV) laser pulses (266 nanometers). Nanosecond ablation is compared with femtosecond ablation where the post-ablation interaction is absent. Subsequent to the early stage expansion, we observe for each studied ablation regime, spectral emission from CN, a typical radical for organic and biological samples. Time-resolved LIBS allows identifying emissions from native molecular species and those due to recombination with ambient air through their different time evolution behaviors.

55

Laboratory evaluation of laser-induced breakdown spectroscopy (LIBS) as a new in situ chemical sensing technique for the deep ocean  

E-Print Network [OSTI]

Present-day expeditionary oceanography is beginning to shift from a focus on short-term ship and submersible deployments to an ocean observatory mode where long-term temporally-focused studies are feasible. As a result, a ...

Michel, Anna Pauline Miranda, 1976-

2007-01-01T23:59:59.000Z

56

Femtosecond laser-induced modification of potassium-magnesium silicate glasses: An analysis of structural changes by near edge x-ray absorption spectroscopy  

SciTech Connect (OSTI)

The effects of femtosecond laser pulse irradiation on the glass structure of alkaline silicate glasses were investigated by x-ray absorption near edge structure spectroscopy using the beamline of the Physikalisch-Technische Bundesanstalt at the electron synchrotron BESSY II in Berlin (Germany) by analyzing the magnesium K-edge absorption peak for different laser fluences. The application of fluences above the material modification threshold (2.1 J/cm{sup 2}) leads to a characteristic shift of {approx}1.0 eV in the K-edge revealing a reduced ({approx}3%) mean magnesium bond length to the ligated oxygen ions (Mg-O) along with a reduced average coordination number of the Mg ions.

Seuthe, T.; Eberstein, M. [Fraunhofer-Institut fuer Keramische Technologien und Systeme (IKTS), Winterbergstrasse 28, 01277 Dresden (Germany); Hoefner, M.; Eichler, H. J.; Grehn, M. [Technische Universitaet Berlin, Institut fuer Optik und Atomare Physik, Strasse des 17. Juni 135, 10623 Berlin (Germany); Reinhardt, F. [Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin (Germany); Tsai, W. J. [ITRI South, Industrial Technology Research Institute, 8 Gongyan Rd., Liu-jia District, Tainan City 73445, Taiwan (China); Bonse, J. [BAM Bundesanstalt fuer Materialforschung und - pruefung, Unter den Eichen 87, 12205 Berlin (Germany)

2012-05-28T23:59:59.000Z

57

Experimental measurements of multiphoton enhanced air breakdown by a subthreshold intensity excimer laser  

SciTech Connect (OSTI)

This work presents density, spectroscopic temperature, and shockwave measurements of laser induced breakdown plasma in atmospheric air by subthreshold intensity (5.5x10{sup 9} W/cm{sup 2}) 193 nm laser radiation. Using molecular spectroscopy and two-wavelength interferometry, it is shown that substantial ionization (>10{sup 16} cm{sup -3}) occurs that is not predicted by collisional cascade (CC) breakdown theory. While the focused laser irradiance is three orders of magnitude below the theoretical collisional breakdown threshold, the substantial photon energy at 193 nm (6.42 eV/photon) compared with the ionization potential of air (15.6 eV) significantly increases the probability of multiphoton ionization effects. By spectroscopically monitoring the intensity of the N{sub 2}{sup +} first negative system (B {sup 2}SIGMA{sub u}{sup +}-X {sup 2}SIGMA{sub g}{sup +}) vibrational bandhead (v{sup '}=0,v{sup ''}=0) at low pressure (20 Torr) where multiphoton effects are dominant, it is shown that two photon excitation, resonant enhanced multiphoton ionization is the primary mechanism for quantized ionization of N{sub 2} to the N{sub 2}{sup +}(B {sup 2}SIGMA{sub u}{sup +}) state. This multiphoton effect then serves to amplify the collisional breakdown process at higher pressures by electron seeding, thereby reducing the threshold intensity from that required via CC processes for breakdown and producing high density laser formed plasmas.

Way, Jesse; Hummelt, Jason; Scharer, John [Department of Electrical and Computer Engineering, University of Wisconsin, Madison, Wisconsin 53706 (United States)

2009-10-15T23:59:59.000Z

58

Laser-Induced Implosion and Thermonuclear Burn  

Science Journals Connector (OSTI)

In high density laser induced fusion, the key idea is laser implosion of ... times liquid density in order to initiate efficient thermonuclear burningl. Fusion yields 50100 times larger than the...5106...joules...

John H. Nuckolls

1974-01-01T23:59:59.000Z

59

Ultraviolet versus infrared: Effects of ablation laser wavelength on the expansion of laser-induced plasma into one-atmosphere argon gas  

SciTech Connect (OSTI)

Laser-induced plasma from an aluminum target in one-atmosphere argon background has been investigated with ablation using nanosecond ultraviolet (UV: 355 nm) or infrared (IR: 1064 nm) laser pulses. Time- and space-resolved emission spectroscopy was used as a diagnostics tool to have access to the plasma parameters during its propagation into the background, such as optical emission intensity, electron density, and temperature. The specific feature of nanosecond laser ablation is that the pulse duration is significantly longer than the initiation time of the plasma. Laser-supported absorption wave due to post-ablation absorption of the laser radiation by the vapor plume and the shocked background gas plays a dominant role in the propagation and subsequently the behavior of the plasma. We demonstrate that the difference in absorption rate between UV and IR radiations leads to different propagation behaviors of the plasma produced with these radiations. The consequence is that higher electron density and temperature are observed for UV ablation. While for IR ablation, the plasma is found with lower electron density and temperature in a larger and more homogenous axial profile. The difference is also that for UV ablation, the background gas is principally evacuated by the expansion of the vapor plume as predicted by the standard piston model. While for IR ablation, the background gas is effectively mixed to the ejected vapor at least hundreds of nanoseconds after the initiation of the plasma. Our observations suggest a description by laser-supported combustion wave for the propagation of the plasma produced by UV laser, while that by laser-supported detonation wave for the propagation of the plasma produced by IR laser. Finally, practical consequences of specific expansion behavior for UV or IR ablation are discussed in terms of analytical performance promised by corresponding plasmas for application with laser-induced breakdown spectroscopy.

Ma Qianli; Motto-Ros, Vincent; Laye, Fabrice; Yu Jin [Universite de Lyon, F-69622, Lyon, France, Universite Lyon 1, Villeurbanne, CNRS, UMR5579, LASIM (France); Lei Wenqi; Bai Xueshi; Zheng Lijuan; Zeng Heping [State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai (China)

2012-03-01T23:59:59.000Z

60

Modeling of Laser-Induced Metal Combustion  

SciTech Connect (OSTI)

Experiments involving the interaction of a high-power laser beam with metal targets demonstrate that combustion plays an important role. This process depends on reactions within an oxide layer, together with oxygenation and removal of this layer by the wind. We present an analytical model of laser-induced combustion. The model predicts the threshold for initiation of combustion, the growth of the combustion layer with time, and the threshold for self-supported combustion. Solutions are compared with detailed numerical modeling as benchmarked by laboratory experiments.

Boley, C D; Rubenchik, A M

2008-02-20T23:59:59.000Z

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


61

Laser-induced ignition modeling of HMX  

Science Journals Connector (OSTI)

Abstract The laser-induced ignition response of HMX has been investigated using a detailed numerical model. The model is one-dimensional, fully transient, and solves the conservation equations for both the condensed and gas phases. The condensed phase representation includes radiation absorption, solid-phase transitions, melting, evaporation, and distributed semi-global decomposition kinetics. The gas phase utilizes a detailed kinetic mechanism to predict species formation and destruction. Ignition occurs in the gas phase and the flame propagates back toward the surface of the HMX in what is known as the snap-back effect. The model then transitions to steady-state combustion. Calculations were performed in which the solid HMX is irradiated with heat fluxes ranging from 50 to 1600W/cm2. Results are compared to empirical data for the laser-induced ignition of HMX. Good agreement with these data and other steady-state data (burning rate, surface temperature, melt thickness) provide the necessary validation of the developed model.

Karl V. Meredith; Matthew L. Gross; Merrill W. Beckstead

2014-01-01T23:59:59.000Z

62

Ignition study of acetone/air mixtures by using laser-induced spark  

Science Journals Connector (OSTI)

The breakdown and the laser-induced spark ignition of acetoneair mixtures were experimentally studied using a nanosecond pulse at 1064nm from a Q-switched Nd:YAG laser. The breakdown was first characterized for different mixtures with acetone and air. This part of the work highlighted the wide variation in the energy absorbed by the plasma during a breakdown. We also demonstrated that the presence of acetone in air tends to reduce the energy required to obtain a breakdown. Next, the ignition of acetoneair mixtures in the equivalence ratio range 0.92.4 was investigated. The probabilities of ignition were calculated in function to the laser energy. However, according to the variability of energy absorption by the plasma, we preferred to present the result according to the energy absorbed by the plasma. The minimum ignition energies were also provided. The minimum ignition energy was obtained for an equivalence ratio of 1.6 and an absorbed energy of 1.15mJ. Finally the characteristics of the plasma (absorption coefficient and kernel temperature) were calculated for the experiments corresponding to minimum ignition energies.

Virginie Tihay; Philippe Gillard; Denis Blanc

2012-01-01T23:59:59.000Z

63

Speciation and spectroscopy of the uranyl and tetravalent plutonium nitrate systems: Fundamental studies and applications to used fuel reprocessing.  

E-Print Network [OSTI]

??This dissertation explores the use of UV-Visible spectroscopy and Time Resolved Laser Induced Fluorescence spectroscopy as near real time process monitors of uranium and plutonium (more)

Smith, Nicholas A

2010-01-01T23:59:59.000Z

64

" A Heterodyne Laser-induced Fluorescence Technique to Determine  

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

A Heterodyne Laser-induced Fluorescence Technique to Determine A Heterodyne Laser-induced Fluorescence Technique to Determine Simultaneously the Bulk and Time Varying Molecule Velocity Distribution." Inventors Ahmed Diallo, Stephane Mazouffre.The method's primary goal is to determine simultaneously the bulk a The method's primary goal is to determine simultaneously the bulk and the time verying part of the molecule velocity distribution using a heterodyne laser induced fluorescence technique. Used in biology, chemistry and plasma physics laser-induced fluorescence is a well known technique to resolve the bulk velocity distribution of probed molecules and atoms in a medium. The novel approach is aimed at determining not only the bulk distribution, but also the time-varying velocity distribution. The two parts of the velocity distribution are key in the characterization of a

65

Dynamics of laser?induced cavitation bubbles  

Science Journals Connector (OSTI)

Bubbles in liquids can be formed in a variety of ways. A convenient method to produce a single bubble in a liquid is to focus a short pulse of laser light into the liquid. A bright light?emitting plasma of obviously high pressure expands forming a gas?vapor bubble. After some time bubble expansion stops at some maximum radius. From thereon the bubble starts to shrink driven by the ambient pressure and leading to a violent collapse possibly followed by rebounds. A mathematical model that describes the evolution of such a laser?induced cavitation bubble is presented. The model takes into account heat conduction of the liquid and gas phases evaporation and condensation processes of the liquid phase gas diffusion from the liquid into the bubble and compressibility of the liquid. A reasonable comparison of theoretical results with experimental data is obtained. [Work partially supported by Internationales Bro des BMBF (Contract RUS?133?1997) and European Commission (INCO?Copernicus Contract ERBIC15CT980141).

Iskander Akhatov; Nailya Vakhitova; Kamil Zakirov; Robert Mettin; Olgert Lindau; Werner Lauterborn

1999-01-01T23:59:59.000Z

66

Biofuel breakdown | EMSL  

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

Biofuel breakdown Biofuel breakdown SCF1 frees plant sugars in lignin for sustainable biofuels Lignin, the tough woody polymer in the walls of plant, binds and protects cellulose...

67

Laser-induced differential normalized fluorescence method for cancer diagnosis  

DOE Patents [OSTI]

An apparatus and method for cancer diagnosis are disclosed. The diagnostic method includes the steps of irradiating a tissue sample with monochromatic excitation light, producing a laser-induced fluorescence spectrum from emission radiation generated by interaction of the excitation light with the tissue sample, and dividing the intensity at each wavelength of the laser-induced fluorescence spectrum by the integrated area under the laser-induced fluorescence spectrum to produce a normalized spectrum. A mathematical difference between the normalized spectrum and an average value of a reference set of normalized spectra which correspond to normal tissues is calculated, which provides for amplifying small changes in weak signals from malignant tissues for improved analysis. The calculated differential normalized spectrum is correlated to a specific condition of a tissue sample. 5 figs.

Vo-Dinh, T.; Panjehpour, M.; Overholt, B.F.

1996-12-03T23:59:59.000Z

68

Laser-induced differential normalized fluorescence method for cancer diagnosis  

DOE Patents [OSTI]

An apparatus and method for cancer diagnosis are disclosed. The diagnostic method includes the steps of irradiating a tissue sample with monochromatic excitation light, producing a laser-induced fluorescence spectrum from emission radiation generated by interaction of the excitation light with the tissue sample, and dividing the intensity at each wavelength of the laser-induced fluorescence spectrum by the integrated area under the laser-induced fluorescence spectrum to produce a normalized spectrum. A mathematical difference between the normalized spectrum and an average value of a reference set of normalized spectra which correspond to normal tissues is calculated, which provides for amplifying small changes in weak signals from malignant tissues for improved analysis. The calculated differential normalized spectrum is correlated to a specific condition of a tissue sample.

Vo-Dinh, Tuan (Knoxville, TN); Panjehpour, Masoud (Knoxville, TN); Overholt, Bergein F. (Knoxville, TN)

1996-01-01T23:59:59.000Z

69

Ultrafast molecular imaging by laser-induced electron diffraction  

SciTech Connect (OSTI)

We address the feasibility of imaging geometric and orbital structures of a polyatomic molecule on an attosecond time scale using the laser-induced electron diffraction (LIED) technique. We present numerical results for the highest molecular orbitals of the CO{sub 2} molecule excited by a near-infrared few-cycle laser pulse. The molecular geometry (bond lengths) is determined within 3% of accuracy from a diffraction pattern which also reflects the nodal properties of the initial molecular orbital. Robustness of the structure determination is discussed with respect to vibrational and rotational motions with a complete interpretation of the laser-induced mechanisms.

Peters, M. [Universite Paris-Sud, Institut des Sciences Moleculaires d'Orsay (CNRS), F-91405 Orsay (France); Departement de Chimie, Universite Laval, Quebec, Quebec G1K 7P4 (Canada); Nguyen-Dang, T. T. [Departement de Chimie, Universite Laval, Quebec, Quebec G1K 7P4 (Canada); Cornaggia, C. [CEA IRAMIS, SPAM, Saclay, Batiment 522, F-91191 Gif-sur-Yvette (France); Saugout, S.; Charron, E.; Keller, A.; Atabek, O. [Universite Paris-Sud, Institut des Sciences Moleculaires d'Orsay (CNRS), F-91405 Orsay (France)

2011-05-15T23:59:59.000Z

70

High resolution analysis of soil elements with laser-induced breakdown  

DOE Patents [OSTI]

The invention is a system and method of detecting a concentration of an element in a soil sample wherein an opening or slot is formed in a container that supports a soil sample that was extracted from the ground whereupon at least a length of the soil sample is exposed via the opening. At each of a plurality of points along the exposed length thereof, the soil sample is ablated whereupon a plasma is formed that emits light characteristic of the elemental composition of the ablated soil sample. Each instance of emitted light is separated according to its wavelength and for at least one of the wavelengths a corresponding data value related to the intensity of the light is determined. As a function of each data value a concentration of an element at the corresponding point along the length of the soil core sample is determined.

Ebinger, Michael H. (Santa Fe, NM); Harris, Ronny D. (Los Alamos, NM)

2010-04-06T23:59:59.000Z

71

E-Print Network 3.0 - alleviates laser-induced choroidal Sample...  

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

laser-induced choroidal Search Powered by Explorit Topic List Advanced Search Sample search results for: alleviates laser-induced choroidal Page: << < 1 2 3 4 5 > >> 1 SPIE...

72

Laser-induced ignition and combustion in a SI engine with direct injection  

Science Journals Connector (OSTI)

Laser-induced ignition has shown huge advantages for the combustion ... (KIT) to investigate the potential of the laser-induced ignition. The emphasis was on improving combustion initiation...

Dipl.-Ing. Volker Gross; Dr.-Ing. Heiko Kubach

2010-07-01T23:59:59.000Z

73

Laser induced electron acceleration in vacuum K. P. Singha)  

E-Print Network [OSTI]

Laser induced electron acceleration in vacuum K. P. Singha) Department of Physics, Indian Institute acceleration by a plane polarized laser wave has been studied in vacuum. Relativistic equations of motion have been solved exactly for electron trajectory and energy as a function of laser intensity, phase

Singh, Kunwar Pal

74

Molecular Dynamics Simulations of Laser Induced Incandescence Dr. Adri van Duin  

E-Print Network [OSTI]

Molecular Dynamics Simulations of Laser Induced Incandescence (LII) Dr. Adri van Duin Associate of Engineering. Laser Induced Incandescence (LII) is a popular method to estimate the properties of soot. Molecular Dynamics Simulations of Laser-Induced Incandescence of Soot Using an Extended ReaxFF Reactive

Bjørnstad, Ottar Nordal

75

Laser induced melting and crystallization of boron doped amorphous silicon  

SciTech Connect (OSTI)

Transient reflectivity experiments have been performed to measure the dynamics of laser-induced melting of amorphous silicon (a-Si) and the crystallization to {micro}c-Si of films with different thicknesses on Corning 7059 glass. The laser-induced melting takes place with a velocity of 13 to 24 m/s, while the solidification is about a factor 10 slower. The crystallization starts at the Si/glass interface and at the surface. In the center of the films Si remains liquid for an extended period of time. The crystallization dynamics point towards an heterogeneous morphology of laser-crystallized Si, where the surface and the interface layers are composed of small grains and the bulk of larger grains.

Nebel, C.E.; Schoeniger, S.; Dahlheimer, B.; Stutzmann, M.

1997-07-01T23:59:59.000Z

76

Anisotropy of Laser-Induced Bulk Damage of Single Crystals  

E-Print Network [OSTI]

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

Krupych, O; Smaga, I; Vlokh, R

2005-01-01T23:59:59.000Z

77

Ultratrace analysis of transuranic actinides by laser-induced fluorescence  

DOE Patents [OSTI]

Ultratrace quantities of transuranic actinides are detected indirectly by their effect on the fluorescent emissions of a preselected fluorescent species. Transuranic actinides in a sample are coprecipitated with a host lattice material containing at least one preselected fluorescent species. The actinide either quenches or enhances the laser-induced fluorescence of the preselected fluorescent species. The degree of enhancement or quenching is quantitatively related to the concentration of actinide in the sample.

Miller, S.M.

1983-10-31T23:59:59.000Z

78

Ultrafast electron beam imaging of femtosecond laser-induced plasma  

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

Ultrafast electron beam imaging of femtosecond laser-induced plasma Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Title Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Publication Type Journal Article Year of Publication 2010 Authors Li, Junjie, Xuan Wang, Zhaoyang Chen, Richard Clinite, Samuel S. Mao, Pengfei Zhu, Zhengming Sheng, Jie Zhang, and Jianming Cao Journal Journal of Applied Physics Volume 107 Issue 8 Date Published 03/2010 Keywords copper, electron beam applications, high-speed optical techniques, laser ablation, plasma diagnostics, plasma production by laser Abstract Plasma dynamics in the early stage of laser ablation of a copper target are investigated in real time by making ultrafast electron shadow images and electron deflectometry measurements. These complementary techniques provide both a global view and a local perspective of the associated transient electric field and charge expansion dynamics. The results reveal that the charge cloud above the target surface is composed predominantly of thermally ejected electrons and that it is self-expanding, with a fast front-layer speed exceeding 107 m/s. The average electric field strength of the charge cloud induced by a pump fluence of 2.2 J/cm2 is estimated to be ∼ 2.4×105 V/m.

79

Characterization of four potential laser-induced fluorescence tracers for diesel engine applications  

Science Journals Connector (OSTI)

Four potential laser-induced fluorescence (LIF) tracers, 1-phenyloctane, 1-phenyldecane, 1-methylnaphthalene, and 2-methylnaphthalene, are characterized for diesel engine applications....

Trost, Johannes; Zigan, Lars; Leipertz, Alfred; Sahoo, Dipankar; Miles, Paul C

2013-01-01T23:59:59.000Z

80

AN ANALYTICAL AND QUANTITATIVE ANALYSIS OF THE LASER-INDUCED INCANDESCENCE OF SOOT  

E-Print Network [OSTI]

AN ANALYTICAL AND QUANTITATIVE ANALYSIS OF THE LASER-INDUCED INCANDESCENCE OF SOOT A Thesis-INDUCED INCANDESCENCE OF SOOT Approved: _________________________ Jerry M. Seitzman, Chairman

Seitzman, Jerry M.

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


81

LASER-INDUCED SHOCK WAVES IN CONDENSED MATTER: SOME TECHNIQUES AND APPLICATIONS  

E-Print Network [OSTI]

LASER-INDUCED SHOCK WAVES IN CONDENSED MATTER: SOME TECHNIQUES AND APPLICATIONS S. N. LUOa,? , D. C, NV 89154, USA; c GPS Division, California Institute of Technology, Pasadena, CA 91125, USA Laser pressure physics. We briefly review some techniques in laser-induced shock waves, including direct laser

Asimow, Paul D.

82

Experimental investigation of ultraviolet laser induced plasma density and temperature evolution in air  

E-Print Network [OSTI]

and collisional cascade processes for pressures ranging from 40 Torr to 5 atm. A laser shadowgraphy diagnosticExperimental investigation of ultraviolet laser induced plasma density and temperature evolution July 2008 We present measurements and analysis of laser induced plasma neutral densities

Scharer, John E.

83

A calibration-independent laser-induced incandescence technique for soot measurement  

E-Print Network [OSTI]

A calibration-independent laser-induced incandescence technique for soot measurement by detecting D. Bachalo Laser-induced incandescence (LII) has proved to be a useful diagnostic tool for spatially incandescence inten- sity, avoiding the need for ex situ calibration that typically uses a source of particles

Gülder, ?mer L.

84

Ultrafast dynamics of the laser-induced solid-to-liquid phase transition in aluminum  

E-Print Network [OSTI]

Ultrafast dynamics of the laser-induced solid-to-liquid phase transition in aluminum A thesis dynamics of the laser-induced solid-to-liquid phase transition in aluminum Eric Mazur Maria Kandyla Abstract This dissertation reports the ultrafast dynamics of aluminum during the solid-to- liquid phase

Mazur, Eric

85

Laser Induced Nuclear Fusion, LINF, In Muonic Molecules With Ultrashort Super Intense Laser Fields  

Science Journals Connector (OSTI)

Muonium molecules where muons replace electrons increase the stability of molecules to ionization at superhigh intensities I >10 20 ? W / cm 2 . We show furthermore from numerical simulations that in the nonsymmetric series pdu dtu ptu the permanent dipole moments can be used to enhance LINF Laser Induced Nuclear Fusion by laser induced recollision of the light nucleus with the heavier nucleus.

Andre D. Bandrauk; Gennady K. Paramonov

2010-01-01T23:59:59.000Z

86

Diagnostics for the detection and evaluation of laser induced damage  

SciTech Connect (OSTI)

The Laser Damage and Conditioning Group at LLNL is evaluating diagnostics which will help make damage testing more efficient and reduce the risk of damage during laser conditioning. The work to date has focused on photoacoustic and scattered light measurements on 1064-nm wavelength HfO{sub 2}/SiO{sub 2} multilayer mirror and polarizer coatings. Both the acoustic and scatter diagnostics have resolved 10 {mu}m diameter damage points in these coatings. Using a scanning stage, the scatter diagnostic can map both intrinsic and laser-induced scatter. Damage threshold measurements obtained using scatter diagnostics compare within experimental error with those measured using 100x Nomarski microscopy. Scatter signals measured during laser conditioning can be used to detect damage related to nodular defects.

Sheehan, L.; Kozlowski, M.; Rainer, F.

1995-01-03T23:59:59.000Z

87

Fundamental studies in the molecular basis of laser-induced retinal damage. Annual report, September 1981-August 1982  

SciTech Connect (OSTI)

This research led to new insights in the fundamental mechanisms involved in laser induced retinal damage and some of the fundamental work on these mechanisms lead to new and exciting avenues in the development of rapidly adjustable molecular light filters with important new possibilities for pulsed-laser eye protection. This report summarizes the significant progress of the past year: (1) Development and Fundamental Mechanism of a Rapidly Adjustable Molecular Filter for Pulsed Laser Eye Protection - this research direction resulted from our investigations on cones of the red-eared swamp turtle, Pseudemys scripta elegans. (2) The Optical Density of Turtle Oil Droplet Solutions - it is important both from a practical and fundamental point of view to determine the optical density of turtle oil-droplet suspensions. In view of the high optical densities in this system, tunable-laser resonance Raman spectroscopy, which is the only technique that has been able to provide high-resolution data, is the only technique that is potentially able to obtain the information. (3) Laser-Induced Molecular Alterations in Turtle Retina. (4) Light Driven Enzymatic Reactions in Photoreceptors. (5) Molecular Cytology of Rod Outer Segments.

Lewis

1982-09-01T23:59:59.000Z

88

Ultrafast laser induced periodic sub-wavelength aluminum surface structures and nanoparticles in air and liquids  

SciTech Connect (OSTI)

In this communication, we demonstrate the generation of laser-induced periodic sub-wavelength surface structures (LIPSS) or ripples on a bulk aluminum (Al) and Al nanoparticles (NPs) by femtosecond (fs) laser direct writing technique. Laser irradiation was performed on Al surface at normal incidence in air and by immersing in ethanol (C{sub 2}H{sub 5}OH) and water (H{sub 2}O) using linearly polarized Ti:sapphire fs laser pulses of ?110 fs pulse duration and ?800?nm wavelength. Field emission scanning electron microscope is utilized for imaging surface morphology of laser written structures and it reveals that the spatial periodicity as well as the surface morphology of the LIPSS depends on the surrounding dielectric medium and also on the various laser irradiation parameters. The observed LIPSS have been classified as low spatial frequency LIPSS which are perpendicularly oriented to the laser polarization with a periodicity from 460 to 620?nm and high spatial frequency LIPSS which spectacles a periodicity less than 100?nm with the orientation parallel to the polarization of the incident laser beam. Fabricated colloidal solutions, which contain the Al NPs, were characterized by UV-Vis absorption spectroscopy and transmission electron microscopy (TEM). TEM results reveal the formation of internal cavities in Al NPs both in ethanol and water. Formation mechanism of LIPSS and cavities inside the nanoparticles are discussed in detail.

Kuladeep, Rajamudili; Dar, Mudasir H.; Rao, D. Narayana, E-mail: dnrsp@uohyd.ac.in, E-mail: dnr-laserlab@yahoo.com [School of Physics, University of Hyderabad, Hyderabad 500046 (India); Deepak, K. L. N. [Department of Physics and Center for Research in Photonics, University of Ottawa, 150 Louis Pasteur, Ottawa K1N6N5, Ontario (Canada)

2014-09-21T23:59:59.000Z

89

Spectroscopy  

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

Spectroscopy Spectroscopy Spectroscopy Print In spectroscopy experiments, a sample is illuminated with light and the various product particles (electrons, ions, or fluorescent photons) are detected and analyzed.The unifying feature is that some "property" of a material is measured as the x-ray (photon) energy is swept though a range of values. At the most basic level, one measures the absorption, transmission, or reflectivity of a sample as a function of photon energy. Probes that use the vacuum ultraviolet (VUV) region of the spectrum (10-100 eV) are very well matched to the elucidation of bonding in solids, surfaces, and molecules; to the investigation of electron-electron correlations in solids, atoms, and ions; and to the study of reaction pathways in chemical dynamics. At the lowest end of this energy range (below 1 eV) we have infrared, far-infrared, and terahertz spectroscopies, which are well matched to vibrational modes and other modes of excitation.

90

E-Print Network 3.0 - applying solution nebulization Sample Search...  

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

13 Plasma volume considerations for analysis of gaseous and aerosol samples using laser-induced breakdown spectroscopy Summary: (iCCD) array. Aerosols were generated by the...

91

Structure Breakdown Workshop Schedule  

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

Breakdown Breakdown Workshop SLAC, Orange Room August 28 - 30 , 2000 Announcement Workshop Poster Workshop Goals: The Goal of the workshop is to review understanding of warm structure breakdown phenomena, to define common terms for comparing tests and to identify avenues for further study. For a partial bibliography, please view the following URL : http://www-project.slac.stanford.edu/lc/wkshp/RFBreakdwn/references/publist.htm Schedule and Presentations: Monday, August 28 8:30 - Operation Experience and Definition of Problem Moderator - G. Loew (initial questions) Opening remarks and introduction (C. Adolphsen) (15min) CERN Structure Operation Results (W. Wuensch) (30 min) NLCTA Structure Operation Results (C. Adolphsen) (30 min) ASTA Structure Operation Results (R. Loewen) (20 min)

92

Spectroscopy  

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

Spectroscopy Print Spectroscopy Print In spectroscopy experiments, a sample is illuminated with light and the various product particles (electrons, ions, or fluorescent photons) are detected and analyzed.The unifying feature is that some "property" of a material is measured as the x-ray (photon) energy is swept though a range of values. At the most basic level, one measures the absorption, transmission, or reflectivity of a sample as a function of photon energy. Probes that use the vacuum ultraviolet (VUV) region of the spectrum (10-100 eV) are very well matched to the elucidation of bonding in solids, surfaces, and molecules; to the investigation of electron-electron correlations in solids, atoms, and ions; and to the study of reaction pathways in chemical dynamics. At the lowest end of this energy range (below 1 eV) we have infrared, far-infrared, and terahertz spectroscopies, which are well matched to vibrational modes and other modes of excitation.

93

Spectroscopy  

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

Spectroscopy Print Spectroscopy Print In spectroscopy experiments, a sample is illuminated with light and the various product particles (electrons, ions, or fluorescent photons) are detected and analyzed.The unifying feature is that some "property" of a material is measured as the x-ray (photon) energy is swept though a range of values. At the most basic level, one measures the absorption, transmission, or reflectivity of a sample as a function of photon energy. Probes that use the vacuum ultraviolet (VUV) region of the spectrum (10-100 eV) are very well matched to the elucidation of bonding in solids, surfaces, and molecules; to the investigation of electron-electron correlations in solids, atoms, and ions; and to the study of reaction pathways in chemical dynamics. At the lowest end of this energy range (below 1 eV) we have infrared, far-infrared, and terahertz spectroscopies, which are well matched to vibrational modes and other modes of excitation.

94

Breakdown of QCD coherence ?  

E-Print Network [OSTI]

We reconsider the calculation of a non-global QCD observable and find the possible breakdown of QCD coherence. This breakdown arises as a result of wide angle soft gluon emission developing a sensitivity to emission at small angles and it leads to the appearance of super-leading logarithms. We use the `gaps between jets' cross-section as a concrete example and illustrate that the new logarithms are intimately connected with the presence of Coulomb gluon contributions. Numerical estimates of their potential phenomenological significance are presented.

A. Kyrieleis; J. R. Forshaw; M. H. Seymour

2006-12-16T23:59:59.000Z

95

E-Print Network 3.0 - absorption laser-induced lyman- Sample...  

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

Powered by Explorit Topic List Advanced Search Sample search results for: absorption laser-induced lyman- Page: << < 1 2 3 4 5 > >> 1 6412 J. Phys. Chcm. 1993,97, 64126417 H +0...

96

CO-CATALYTIC ABSORPTION LAYERS FOR CONTROLLED LASER-INDUCED CHEMICAL VAPOR DEPOSITION OF CARBON NANOTUBES  

E-Print Network [OSTI]

The concept of co-catalytic layer structures for controlled laser-induced chemical vapor deposition of carbon nanotubes is established, in which a thin Ta support layer chemically aids the initial Fe catalyst reduction. This enables a significant...

Michaelis, F.B.; Weatherup, R.S.; Bayer, B.C.; Bock, M.C.D; Sugime, H.; Caneva, S.; Robertson, J.; Baumberg, J.J.; Hofmann, S.

2014-02-24T23:59:59.000Z

97

Two-photon nitric oxide laser-induced fluorescence measurements in a diesel engine  

Science Journals Connector (OSTI)

A two-photon nitric oxide (NO) laser-induced fluorescence (LIF) technique was developed and applied to study in-cylinder diesel combustion. The technique prevents many problems...

Martin, Glen C; Mueller, Charles J; Lee, Chia-Fon F

2006-01-01T23:59:59.000Z

98

Assessment of soot particle vaporization effects during laser-induced incandescence with  

E-Print Network [OSTI]

Assessment of soot particle vaporization effects during laser-induced incandescence with time-induced incandescence (LII) has been successfully used for soot volume fraction and particle size measurements

Hahn, David W.

99

Laser induced spark ignition of coaxial methane/oxygen/nitrogen diffusion flames  

Science Journals Connector (OSTI)

We report the laser induced spark ignition (LSI) of coaxial methane/oxygen/nitrogen diffusion flames using the 1064 nm output of a Q-switched Nd:YAG laser. The minimum ignition energy...

Li, Xiaohui; Yu, Yang; Yu, Xin; Liu, Chang; Fan, Rongwei; Chen, Deying

2014-01-01T23:59:59.000Z

100

Ultrafast Laser Induced Thermo-Elasto-Visco-Plastodynamics in Single Crystalline Silicon  

E-Print Network [OSTI]

pulse width in Laser Induced Stress Waves Thermometry (LISWT) for single crystalline silicon processing motivated the work. The model formulation developed is of a hyperbolic type capable of characterizing non-thermal melting and thermo...

Qi, Xuele

2011-02-22T23:59:59.000Z

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


101

Laser-Induced Photochemical Reactions of Methanol, Ethanol, 1-Propanol, and 2-Propanol  

Science Journals Connector (OSTI)

This study focuses on the carbon dioxide laser-induced excitation and resultant dissociation of several members of a group of carbon-oxygen (C-O)-containing molecules, the alcohols...

Johnson, R A; Stanley, A E

1988-01-01T23:59:59.000Z

102

Laser Induced Nuclear Fusion, LINF, In Muonic Molecules With Ultrashort Super Intense Laser Fields  

SciTech Connect (OSTI)

Muonium molecules where muons replace electrons increase the stability of molecules to ionization at superhigh intensities, I>10{sup 20} W/cm{sup 2}. We show furthermore from numerical simulations that in the nonsymmetric series, pdu, dtu, ptu, the permanent dipole moments can be used to enhance LINF, Laser Induced Nuclear Fusion by laser induced recollision of the light nucleus with the heavier nucleus.

Bandrauk, Andre D. [Faculte des sciences, Universite de Sherbrooke, Quebec, J1K 2R1 (Canada); Paramonov, Gennady K. [Institut fur Chemie, FU Berlin-14195 Berlin (Germany)

2010-02-02T23:59:59.000Z

103

High precision in-cylinder gas thermometry using Laser Induced Gratings: Quantitative measurement of evaporative cooling with gasoline/alcohol blends in a GDI optical engine  

Science Journals Connector (OSTI)

Abstract The first application of Laser Induced Thermal Gratings Spectroscopy (LITGS) for precision thermometry in a firing GDI optical engine is reported. Crank-angle resolved temperature values were derived from LITGS signals generated in fuel vapour with a pressure dependent precision in the range 0.11.0% allowing differences in evaporative or charge cooling effects arising from a variety of ethanol and methanol blends with a model gasoline fuel to be quantified. In addition, fluctuations in temperature arising from cyclic variations in compression were directly detected and measured.

Ben Williams; Megan Edwards; Richard Stone; John Williams; Paul Ewart

2014-01-01T23:59:59.000Z

104

Nervous breakdown causes  

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

Nervous breakdown causes Nervous breakdown causes Name: Renee Nuckols Status: N/A Age: N/A Location: N/A Country: N/A Date: Around 1993 Question: Physiologically, what causes a mental/nervous breakdown besides normal everyday stress? Is it a process that kills neurons? Also please include some internal and external symptoms that occur prior to, during, and after a nervous breakdown. Replies: "Nervous breakdown" may be a misnomer, though. What "breaks down" is not so much the nerves and neurons, but the adrenal glands. A more accurate term would be the "exhaustion phase of the general adaption syndrome," but obviously that is quite a mouthful. Excessive STRESS is what can cause "nervous breakdowns." Stress includes the obvious things like exam pressures, trouble with parents or teachers, peer pressure, but also includes things like a significant personal achievement, making a major purchase, changes in routines of life (sleeping, eating habits), moving to a different part of town - even the change in seasons and temperatures. It can come from almost anything which causes a disturbance in normal living. Stress triggers a number of physiological changes collectively termed "GENERAL ADAPTATION SYNDROME." There are three phases: 1) alarm, 2) resistance, and 3) exhaustion. These phases are controlled and regulated by the adrenal glands. Your adrenal glands lie just above your kidneys and are composed of inner and outer parts. The inner part is called the adrenal medulla, and it secretes the hormones adrenaline and noradrenaline. These hormones help your body deal with stressful situations. If you were alone and met a gang in some back alley, your adrenal glands would flood your body with the hormones, your blood pressure, heart rate, sweat production would shoot way high! Your body is in a "FIGHT or FLIGHT" mode. (Just thinking about getting in such a situation may have caused some stress!) Well, whenever your body deals with smaller stresses, the same hormones are released. The outer part of the adrenal glands is the adrenal cortex. They also produce hormones, but slightly different ones: glucocorticoids and mineralcorticoids. Glucocorticoids can increase blood sugar levels profoundly, while mineralcorticoids affect mineral excretion. These hormones are largely responsible for helping the body deal with prolonged stress. They help provide extra energy and blood supply. For instance, if you had a whole week of finals, your adrenal cortex would work overtime as you burn the midnight oil studying. These instances are the "resistance" phase of the general adaptation syndrome.

105

Breakdown of Coherence ?  

E-Print Network [OSTI]

In a recent paper, Albrecht Kyrieleis, Jeff Forshaw and I discovered a new tower of super-leading logarithms in gaps between jets cross sections. After discussions with the referee of our paper and further investigation, we have come to view this as a breakdown of naive coherence for initial state radiation. In this talk I illustrate this statement in a simple way, and show how it results in the super-leading logarithms.

Michael H. Seymour

2007-10-15T23:59:59.000Z

106

Laser-induced quadrupole-quadrupole collisional energy transfer in Xe-Kr systems  

Science Journals Connector (OSTI)

Experimental investigation of laser-induced quadrupole-quadrupole collisional energy transfer between Xe and Kr is reported in this paper. The excitation spectrum of laser-induced collisional energy transfer (LICET) is characterized by a slowly decreasing tail on the blue side of the peak and a width of ?30 cm?1. The experimental evidence shows that in the quasistatic wing the quadrupole-quadrupole LICET spectrum follows a power law that is different from the dipole-dipole LICET line shape and the profile of the quadrupole-quadrupole LICET decreases more slowly than the dipole-dipole LICET profile. The results indicate that the laser-induced quadrupole-quadrupole collision can be considered as a practical process to transfer energy selectively from a storage state making a parity-nonallowed transition to a target state making a parity-allowed transition.

Zhenzhong Lu (???); Deying Chen (???); Rongwei Fan (???); Yuanqin Xia (???)

2012-06-01T23:59:59.000Z

107

Laser-induced plasma ignition studies in a model scramjet engine  

Science Journals Connector (OSTI)

An experimental investigation of the behavior of laser-induced plasma (LIP) ignition for scramjet inlet injection is presented. The presented results demonstrate for the first time, that LIP can be used to promote the formation of hydroxyl in a hypersonic flow. The temporal evolution of the LIP-ignited region is monitored using the planar laser-induced fluorescence technique on the hydroxyl radical. This study is the first laser spark study in a hypersonic flow, shown to generate combustion products where they would not otherwise occur.

Stefan Brieschenk; Sean OByrne; Harald Kleine

2013-01-01T23:59:59.000Z

108

Microbial breakdown of Phaeocystis mucopolysaccharides  

Science Journals Connector (OSTI)

It was shown that the incomplete degradation of mucopolysaccharides was not due to inherent resistance to breakdown in parts of the mucus carbohydrates but

109

Use of laser-induced ionization to detect soot inception in premixed flames  

SciTech Connect (OSTI)

Experimental measurements of laser-induced ionization were performed for ethene-air premixed flames operated near the soot inception point. Soot was ionized with a pulsed laser operated at 532 nm. The ionization signal was collected with a tungsten electrode located in the postflame region. Ionization signals were collected by use of both single-electrode and dual-electrode configurations. Earlier laser-induced- ionization studies focused on the use of a single biased electrode to generate the electric field, with the burner head serving as the path to ground. In many practical combustion systems, a path to ground is not readily available. To apply the laser-induced- ionization diagnostic to these geometries, a dual-electrode geometry must be employed. The influence of electrode configuration, flame equivalence ratio, and flame height on ionization signal detection was determined. The efficacy of the laser-induced-ionization diagnostic in detecting soot inception in the postflame region of a premixed flame by use of a dual-electrode configuration was investigated. Of the dual-electrode configurations tested, the dual-electrode geometry oriented parallel to the laser beam was observed to be most sensitive for detecting the soot inception point in a premixed flame.

Manzello, Samuel L.; Lee, Eui Ju; Mulholland, George W

2005-08-20T23:59:59.000Z

110

Laser-induced plasma cloud interaction and ice multiplication under cirrus cloud conditions  

Science Journals Connector (OSTI)

...electrode free by high-power ultrashort laser...AIDA). High-power lasers allow producing...above a critical power of 36 GW in air...respectively. (A) Chamber gas phase temperature...laser-induced ice generation is apparent from...s. The laser was fired at t = 400 s when the...

Thomas Leisner; Denis Duft; Ottmar Mhler; Harald Saathoff; Martin Schnaiter; Stefano Henin; Kamil Stelmaszczyk; Massimo Petrarca; Raphalle Delagrange; Zuoqiang Hao; Johannes Lder; Yannick Petit; Philipp Rohwetter; Jrme Kasparian; Jean-Pierre Wolf; Ludger Wste

2013-01-01T23:59:59.000Z

111

Strategies for laser-induced fluorescence detection of nitric oxide in high-pressure flames.  

E-Print Network [OSTI]

engines and gas turbines where the combustion chamber is at high pressure. Despite the use of catalyticStrategies for laser-induced fluorescence detection of nitric oxide in high-pressure flames. II. A combustion systems3�13 and thus develop new schemes to mini- mize NO effluent. The high operating pressure

Lee, Tonghun

112

Laser-induced spark ignition of H2/O2/Ar mixtures  

Science Journals Connector (OSTI)

Laser-induced spark ignition of hydrogen-oxygen-argon mixtures was experimentally investigated using a Q-swiched Nd:YAG laser to break down the gas at 532 nm. The laser-based high-speed schlieren system was emplo...

ChangJian Wang; ShengLi Xu; GuangMing Jia

2007-12-01T23:59:59.000Z

113

Laser-induced thermal, orientational, and density nonlinear optical effects in nematic liquid crystals  

Science Journals Connector (OSTI)

We present a theoretical analysis of transient diffractions in nematic liquid crystals, where the nonlinear optical response is due to laser-induced changes in the temperature, density, and director axis reorientation. Our solutions of the field-induced reorientation equation and the coupled density and thermal conduction equations provide a quantitative theoretical model for the experimentally observed grating diffractions, oscillations, and relaxation phenomena.

I. C. Khoo; J. Y. Hou; G. L. Din; Y. L. He; D. F. Shi

1990-07-15T23:59:59.000Z

114

Transient phenomena in the dielectric breakdown of HfO{sub 2} optical films probed by ultrafast laser pulse pairs  

SciTech Connect (OSTI)

The laser induced breakdown threshold of HfO{sub 2} films is studied with single pairs of pulses of variable delay and 50 fs and 1 ps pulse duration. Two distinct transient regimes are observed that can be related to the relaxation of the electron density from the conduction band via an intermediate state to the valence band. The experimental results are in good agreement with a theoretical model that assumes occupation of mid gap states after the first pulse on a time scale of several tens of picoseconds and subsequent decay of this population via recombination with holes in the valence band on a time scale of several tens of milliseconds.

Nguyen, Duy N.; Emmert, Luke A.; Rudolph, Wolfgang [Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Patel, Dinesh; Menoni, Carmen S. [Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States)

2010-11-08T23:59:59.000Z

115

Process Analysis of Recycled Thermoplasts from Consumer Electronics by Laser-Induced Plasma Spectroscopy  

Science Journals Connector (OSTI)

The practicability of LIPS for the elemental monitoring of recycled plastics was tested during a campaign at a double chain extruder (see Figure 1b) within a recycling plant. ... To evaluate whether the LIPS system can detect a concentration gradient during a load change at the extruder, the emission signals of Sb and Ti were monitored during the transition between the extrusion of unused polymeric material (ABS) and recycled plastic (granulate from casings of electronic waste). ...

Herbert Fink; Ulrich Panne; Reinhard Niessner

2002-07-31T23:59:59.000Z

116

Characterization of hydrocarbon and mixed layers in TEXTOR by laser induced ablation spectroscopy  

E-Print Network [OSTI]

: 134.95.83.67 The article was downloaded on 10/03/2012 at 13:13 Please note that terms and conditions apply. View the table of contents for this issue, or go to the journal homepage for more Home Search the plasma discharge by intense laser radiation. The light emitted by particles entering the edge

Giesen, Thomas

117

DOE Work Breakdown Structure Handbook  

Broader source: Energy.gov [DOE]

This handbook provides suggested guidance and best practices on the development of product-oriented Work Breakdown Structures (WBS) that should be used by all projects within DOE to organize and...

118

AFM CHARACTERIZATION OF LASER INDUCED DAMAGE ON CDZNTE CRYSTAL SURFACES  

SciTech Connect (OSTI)

Semi-conducting CdZnTe (or CZT) crystals can be used in a variety of detector-type applications. CZT shows great promise for use as a gamma radiation spectrometer. However, its performance is adversely affected by point defects, structural and compositional heterogeneities within the crystals, such as twinning, pipes, grain boundaries (polycrystallinity), secondary phases and in some cases, damage caused by external forces. One example is damage that occurs during characterization of the surface by a laser during Raman spectroscopy. Even minimal laser power can cause Te enriched areas on the surface to appear. The Raman spectra resulting from measurements at moderate intensity laser power show large increases in peak intensity that is attributed to Te. Atomic Force Microscopy (AFM) was used to characterize the extent of damage to the CZT crystal surface following exposure to the Raman laser. AFM data reveal localized surface damage in the areas exposed to the Raman laser beam. The degree of surface damage to the crystal is dependent on the laser power, with the most observable damage occurring at high laser power. Moreover, intensity increases in the Te peaks of the Raman spectra are observed even at low laser power with little to no visible damage observed by AFM. AFM results also suggest that exposure to the same amount of laser power yields different amounts of surface damage depending on whether the exposed surface is the Te terminating face or the Cd terminating face of CZT.

Hawkins, S; Lucile Teague, L; Martine Duff, M; Eliel Villa-Aleman, E

2008-06-10T23:59:59.000Z

119

Application of a ratiometric laser induced fluorescence (LIF) thermometry for micro-scale temperature measurement for natural convection flows  

E-Print Network [OSTI]

A ratiometric laser induced fluorescence (LIF) thermometry applied to micro-scale temperature measurement for natural convection flows. To eliminate incident light non-uniformity and imperfection of recording device, two fluorescence dyes are used...

Lee, Heon Ju

2004-11-15T23:59:59.000Z

120

Laser-induced chemical liquid phase deposition of copper from aqueous solutions without reducing agents  

SciTech Connect (OSTI)

Laser-induced chemical liquid phase deposition of copper without a traditional reducing agent has been used for the first time to obtain conductive patterns on a dielectric surface having a reducing ability. It is shown that phenol-formaldehyde binder of the dielectric (glass fibre) can successfully play the role of a reducing agent in this process. The resulting copper sediments have low electrical resistance and good topology. (interaction of laser radiation with matter. laser plasmas)

Kochemirovsky, V A; Tumkin, I I; Logunov, L S; Safonov, S V; Menchikov, Leonid G

2012-08-31T23:59:59.000Z

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


121

RF breakdown effects in microwave power amplifiers  

E-Print Network [OSTI]

Electrical stresses in the transistors of high-efficiency switching power amplifiers can lead to hot-electron-induced "breakdown" in these devices. This thesis explores issues related to breakdown in the Transcom TC2571 ...

Arumilli, Gautham Venkat

2007-01-01T23:59:59.000Z

122

Laser-induced damage in dielectrics with nanosecond to subpicosecond pulses. I. Experimental. Part 1  

SciTech Connect (OSTI)

The authors report extensive laser-induced damage threshold measurements on pure and multilayer dielectrics at 1053 and 526 mm for pulse durations, {tau}, ranging from 140 fs to 1 ns. Qualitative differences in the morphology of damage and a departure from the diffusion-dominated {tau}{sup 1/2} scaling indicate that damage results from plasma formation and ablation for {tau}{le}10 ps and from conventional melting and boiling for {tau}>50 ps. A theoretical model based on electron production via multiphoton ionization, Joule heating, and collisional (avalanche) ionization is in good agreement with both the pulsewidth and wavelength scaling of experimental results.

Stuart, B.C.; Herman, S.; Perry, M.D.

1994-12-01T23:59:59.000Z

123

Cooperative effect of ultraviolet and near-infrared beams in laser-induced condensation  

SciTech Connect (OSTI)

We demonstrate the cooperative effect of near infrared (NIR) and ultraviolet (UV) beams on laser-induced condensation. Launching a UV laser after a NIR pulse yields up to a 5-fold increase in the production of nanoparticles (25300 nm) as compared to a single NIR beam. This cooperative effect exceeds the sum of those from the individual beams and occurs for delays up to 1 ?s. We attribute it to the UV photolysis of ozone created by the NIR pulses. The resulting OH radicals oxidize NO{sub 2} and volatile organic compounds, producing condensable species.

Matthews, M.; Henin, S.; Pomel, F.; Kasparian, J.; Wolf, J.-P. [Universit de Genve, GAP-Biophotonics, Chemin de Pinchat 22, 1211 Geneva 4 (Switzerland)] [Universit de Genve, GAP-Biophotonics, Chemin de Pinchat 22, 1211 Geneva 4 (Switzerland); Thberge, F.; Daigle, J.-F. [Defence R and D Canada Valcartier, 2459 de la Bravoure Blvd., Quebec (Qc) G3J 1X5 (Canada)] [Defence R and D Canada Valcartier, 2459 de la Bravoure Blvd., Quebec (Qc) G3J 1X5 (Canada); Lassonde, P.; Kieffer, J.-C. [INRS-EMT, 1650 Lionel Boulet Blvd., Varennes, Quebec (Qc) J3X1S2 (Canada)] [INRS-EMT, 1650 Lionel Boulet Blvd., Varennes, Quebec (Qc) J3X1S2 (Canada)

2013-12-23T23:59:59.000Z

124

Laser-induced magnesium production from magnesium oxide using reducing agents  

SciTech Connect (OSTI)

Experiments for laser induced production of magnesium (Mg) from magnesium oxide (MgO) using reducing agents (R) were conducted. In these experiments, continuous wave CO{sub 2} focused laser is focused on a mixture of magnesium oxide and reducing agent. High power density of focused laser leads to high temperature and the reduction reaction resulting in Mg production. The resultant vapor is collected on a copper plate and analyzed in terms of magnesium deposition efficiency. Deposition efficiencies with various reducing agents such as Zr, C, and Si have been measured to be 60, 9.2, and 12.1 mg/kJ respectively. An excess addition of reducing agent over their corresponding reaction stoichiometric amounts is found to be optimum condition for the most of performed laser induced reactions. In addition, utilizing solar-pumped laser in Mg production with reducing agent will reduce CO{sub 2} emission and produce magnesium with high-energy efficiency and large throughput.

Mohamed, M. S.; Yabe, T.; Baasandash, C.; Sato, Y.; Mori, Y.; Shi-Hua, Liao; Sato, H.; Uchida, S. [Entropia Laser Initiative, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro, Tokyo 152-8552 (Japan)

2008-12-01T23:59:59.000Z

125

Free electron properties of metals under ultrafast laser-induced electron-phonon nonequilibrium: a first-principles study  

E-Print Network [OSTI]

Free electron properties of metals under ultrafast laser-induced electron-phonon nonequilibrium CEA-DIF, 91297 Arpajon, France (Dated: April 3, 2014) The electronic behavior of various solid metals modelled based on the free electron classical theory, the free electron number is a key parameter. However

Paris-Sud XI, Université de

126

2-dimensional ion velocity distributions measured by laser-induced fluorescence above a radio-frequency biased silicon wafer  

E-Print Network [OSTI]

2-dimensional ion velocity distributions measured by laser-induced fluorescence above a radio-frequency cm diameter, 2.2 MHz-biased silicon wafer in a commercial inductively coupled plasma processing rf frequencies,5­7,18 non-sinusoidal waveforms8 and pulsed power.9,19 Control of IEDs in many

California at Los Angles, University of

127

Atomistic modeling of femtosecond laser-induced melting and atomic mixing in Au film Cu substrate system  

E-Print Network [OSTI]

, including laser surface alloying, cladding, annealing, and hardening, e.g. [1­6]. The improvement of surfaceAtomistic modeling of femtosecond laser-induced melting and atomic mixing in Au film ­ Cu substrate modification by laser irradiation is in the core of many modern processing and fabrication techniques

Zhigilei, Leonid V.

128

Time-resolved diffraction profiles and atomic dynamics in short-pulse laser-induced structural transformations: Molecular dynamics study  

E-Print Network [OSTI]

Time-resolved diffraction profiles and atomic dynamics in short-pulse laser-induced structural dynamics simulations of a 20 nm Au film irradiated with 200 fs laser pulses of different intensity in time-resolved x-ray and electron diffraction experiments. Three processes are found to be responsible

Zhigilei, Leonid V.

129

I CALCULATIONS ON ISOTOPE SEPARATION BY LASER INDUCED PHOTODISSOCIATION OF POLYATOMIC MOLECULES  

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

; ; . I CALCULATIONS ON ISOTOPE SEPARATION BY LASER INDUCED PHOTODISSOCIATION OF POLYATOMIC MOLECULES F i n a l Report Willis E . Lamb, JY. U n i v e r s i t y of Arizona Tucson, Arizona 85721 NOTICE report was prepared 86 an account of work sponsored by the United Stater Government. Neither the United S t a m nor the United States Department of Encrwi, nor any of their employees, nor any of thelr contractors, Subcontractors, o r their employer, maker any warranty, exprels or Implied. or apumn my k@ liability or responsibility for the aceuraey. eompletencu or uvfulneu of any informtion, apparatus. product Process disclosed. or rtpreYnu that its ur would not infringe privately o m d righu. November 1978 Prepared f o r TIE UNITED STATES DEPARTMENT OF ENERGY Under Contract No. EN-77-S-02--000

130

Demonstration of Laser Induced X-Ray Generation in an Expanding Laser Produced Plasma  

Science Journals Connector (OSTI)

X-ray emission at 10 nm stimulated by visible laser radiation at 614.2 nm in a beryllium laser produced plasma was investigated. A method of laser induced quenching of metastable ions was applied to He-like Be2+ ions in the 1s2s 1S0 state. Laser excitation to the 1s2p 1P1 state was followed by an intense x-ray emission at a resonance 1s2 1S0-1s2p 1P1 transition. Time, angular, and polarization characteristics of the radiation were studied; a linear polarization and a dipole type angular distribution have been found. The total energy radiated in a 1.5 ns pulse amounted to 10 ?J.

D. M. Simanovskii, A. N. Gladskikh, L. A. Shmaenok, and S. V. Bobashev

1996-07-29T23:59:59.000Z

131

Quantitative Analysis of Deuterium in Zircaloy Using Double-Pulse Laser-Induced Breakdown Spectrometry (LIBS) and Helium Gas Plasma without a Sample Chamber  

Science Journals Connector (OSTI)

Furthermore, it will also meet the anticipated needs of future nuclear fusion power plants, as well as other important fields of application in the foreseeable future. ... In the thermonuclear fusion reactor, one of the two fuel components used is the deuterium, which is chemically bonded in the solid LiD compound. ...

H. Suyanto; Z. S. Lie; H. Niki; K. Kagawa; K. Fukumoto; Hedwig Rinda; S. N. Abdulmadjid; A. M. Marpaung; M. Pardede; M. M. Suliyanti; A. N. Hidayah; E. Jobiliong; T. J. Lie; M. O. Tjia; K. H. Kurniawan

2012-01-27T23:59:59.000Z

132

CoverSheet  

Office of Scientific and Technical Information (OSTI)

and through theoretical considerations on water-rock interactions. ChemCam 1,2 uses laser-induced breakdown spectroscopy (LIBS) to produce atomic emission spectra of small...

133

COST BREAKDOWN AWARD NO: START DATE: EXPIRATION DATE: FISCAL...  

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

COST BREAKDOWN AWARD NO: START DATE: EXPIRATION DATE: FISCAL YEAR BREAKDOWN OF FUNDS ELEMENTS FY FY FY FY FY TOTAL Direct Labor Overhead Materials Supplies Travel Other Direct...

134

Comparative study of laser-induced plasma emission of hydrogen from zircaloy-2 samples in atmospheric and low pressure ambient helium gas  

Science Journals Connector (OSTI)

An experimental study has been performed to demonstrate the advantage of employing ambient helium gas in the spectral quality improvement of hydrogen emission in laser-induced plasma from zircaloy-2 samples at...

M. Pardede; R. Hedwig; M.M. Suliyanti; Z.S. Lie; T.J. Lie

2007-11-01T23:59:59.000Z

135

Directed Assembly of Bi Metallic Nanoparticles by Pulsed Laser Induced Dewetting: a Unique Nanoscale Time and Length Scale Regime  

SciTech Connect (OSTI)

Pulsed laser induced dewetting (PLiD) was used to assemble patterned, nanoscale metallic thin film features into bi metallic nanoparticles. The liquid-phase flow is related to a conventional droplet impact test and in appropriate dimensions have inertial and viscoinertial flow characteristics. The final size, morphology, composition, and inter-diffusion of the nanoparticles is governed by the interplay of capillary, inertial and viscous forces and an appropriate dimensional regime defined by competing Rayleigh-Plateau and spinodal instabilities.

Fowlkes, Jason Davidson [ORNL; Rack, P. D. [University of Tennessee, Knoxville (UTK); Wu, Yeuyeng [University of Tennessee, Knoxville (UTK)

2010-01-01T23:59:59.000Z

136

Laser-Induced Fluorescence Detection in High-Throughput Screening of Heterogeneous Catalysts and Single Cells Analysis  

SciTech Connect (OSTI)

Laser-induced fluorescence detection is one of the most sensitive detection techniques and it has found enormous applications in various areas. The purpose of this research was to develop detection approaches based on laser-induced fluorescence detection in two different areas, heterogeneous catalysts screening and single cell study. First, the author introduced laser-induced imaging (LIFI) as a high-throughput screening technique for heterogeneous catalysts to explore the use of this high-throughput screening technique in discovery and study of various heterogeneous catalyst systems. This scheme is based on the fact that the creation or the destruction of chemical bonds alters the fluorescence properties of suitably designed molecules. By irradiating the region immediately above the catalytic surface with a laser, the fluorescence intensity of a selected product or reactant can be imaged by a charge-coupled device (CCD) camera to follow the catalytic activity as a function of time and space. By screening the catalytic activity of vanadium pentoxide catalysts in oxidation of naphthalene, they demonstrated LIFI has good detection performance and the spatial and temporal resolution needed for high-throughput screening of heterogeneous catalysts. The sample packing density can reach up to 250 x 250 subunits/cm{sup 2} for 40-{micro}m wells. This experimental set-up also can screen solid catalysts via near infrared thermography detection. In the second part of this dissertation, the author used laser-induced native fluorescence coupled with capillary electrophoresis (LINF-CE) and microscope imaging to study the single cell degranulation. On the basis of good temporal correlation with events observed through an optical microscope, they have identified individual peaks in the fluorescence electropherograms as serotonin released from the granular core on contact with the surrounding fluid.

Hui Su

2001-05-25T23:59:59.000Z

137

Laser-induced fluorescence velocity measurements of a diverging cusped-field thruster  

Science Journals Connector (OSTI)

Measurements are presented of the most probable time-averaged ion velocities within the acceleration channel and in the plume of a diverging cusped-field thruster operating on xenon. Xenon ion velocities for the thruster are derived from laser-induced fluorescence measurements of the 5d[4]7/26p[3]5/2 xenon ion excited state transition centred at ? = 834.72?nm. The thruster is operated in both a high-current mode, where the anode discharge current is shown to oscillate periodically, and a low-current mode where operation is relatively quiescent. In the low-current mode, ion emission is predominantly in the form of a conical jet, whereas in the high-current mode, the emission is still divergent but more diffuse throughout the cone angle. These time-average measurements provide insight into the structure of the acceleration region. However, discerning the mechanism for the diffuse ion emission in the strongly oscillating high-current mode will require ion velocity measurements capable of resolving the time-dependent behaviour of the discharge.

N A MacDonald; M A Cappelli; S R Gildea; M Martnez-Snchez; W A Hargus Jr

2011-01-01T23:59:59.000Z

138

Microwave pulse compression from a storage cavity with laser-induced switching  

DOE Patents [OSTI]

A laser-induced switch and a multiple cavity configuration are disclosed for producing high power microwave pulses. The microwave pulses are well controlled in wavelength and timing, with a quick rise time and a variable shape and power of the pulse. In addition, a method of reducing pre-pulse leakage to a low level is disclosed. Microwave energy is directed coherently to one or more cavities that stores the energy in a single mode, represented as a standing wave pattern. In order to switch the stored microwave energy out of the main cavity and into the branch waveguide, a laser-actuated switch is provided for the cavity. The switch includes a laser, associated optics for delivering the beam into the main cavity, and a switching gas positioned at an antinode in the main cavity. When actuated, the switching gas ionizes, creating a plasma, which becomes reflective to the microwave energy, changing the resonance of the cavity, and as a result the stored microwave energy is abruptly switched out of the cavity. The laser may directly pre-ionize the switching gas, or it may pump an impurity in the switching gas to an energy level which switches when a pre-selected cavity field is attained. Timing of switching the cavities is controlled by varying the pathlength of the actuating laser beam. For example, the pathlengths may be adjusted to output a single pulse of high power, or a series of quick lower power pulses.

Bolton, Paul R. (Menlo Park, CA)

1992-01-01T23:59:59.000Z

139

Laser-Induced Fluorescence Detection in High-Throughput Screening of Heterogeneous Catalysts and Single Cells Analysis  

SciTech Connect (OSTI)

Laser-induced fluorescence detection is one of the most sensitive detection techniques and it has found enormous applications in various areas. The purpose of this research was to develop detection approaches based on laser-induced fluorescence detection in two different areas, heterogeneous catalysts screening and single cell study. First, we introduced laser-induced imaging (LIFI) as a high-throughput screening technique for heterogeneous catalysts to explore the use of this high-throughput screening technique in discovery and study of various heterogeneous catalyst systems. This scheme is based on the fact that the creation or the destruction of chemical bonds alters the fluorescence properties of suitably designed molecules. By irradiating the region immediately above the catalytic surface with a laser, the fluorescence intensity of a selected product or reactant can be imaged by a charge-coupled device (CCD) camera to follow the catalytic activity as a function of time and space. By screening the catalytic activity of vanadium pentoxide catalysts in oxidation of naphthalene, we demonstrated LIFI has good detection performance and the spatial and temporal resolution needed for high-throughput screening of heterogeneous catalysts. The sample packing density can reach up to 250 x 250 subunits/cm{sub 2} for 40-{micro}m wells. This experimental set-up also can screen solid catalysts via near infrared thermography detection.

Hui Su

2001-05-01T23:59:59.000Z

140

Study of the Effect of Ultraviolet Exposure on Bio-oil by Laser-Induced Fluorescence Spectroscopy  

Science Journals Connector (OSTI)

Main characteristics of the used biomass feedstocks are summarized in Table 1. ... Main Characteristics of Biomass Feedstocks ...

Markandey M. Tripathi; El Barbary M. Hassan; Fang-Yu Yueh; Jagdish P. Singh; Philip H. Steele

2010-11-01T23:59:59.000Z

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


141

Ignition with Laser Break-Down  

Science Journals Connector (OSTI)

It is considered that ignition with laser break-down is one of the applications of solid-state lasers. This paper shows basic experimental results indicating the advantages of laser...

Furutani, Hirohide; Saito, Takeshi

142

Two photon absorption laser induced fluorescence measurements of neutral density in a helicon plasma  

SciTech Connect (OSTI)

We have developed a new diagnostic based on two-photon absorption laser induced fluorescence (TALIF). We use a high intensity (5?MW/cm{sup 2}), narrow bandwidth (0.1?cm{sup ?1}) laser to probe the ground state of neutral hydrogen, deuterium and krypton with spatial resolution better than 0.2?cm, a time resolution of 10?ns, and a measurement cadence of 20?Hz. Here, we describe proof-of-principle measurements in a helicon plasma source that demonstrate the TALIF diagnostic is capable of measuring neutral densities spanning four orders of magnitude; comparable to the edge neutral gradients predicted in the DIII-D tokamak pedestal. The measurements are performed in hydrogen and deuterium plasmas and absolute calibration is accomplished through TALIF measurements in neutral krypton. The optical configuration employed is confocal, i.e., both light injection and collection are accomplished with a single lens through a single optical port in the vacuum vessel. The wavelength resolution of the diagnostic is sufficient to separate hydrogen and deuterium spectra and we present measurements from mixed hydrogen and deuterium plasmas that demonstrate isotopic abundance measurements are feasible. Time resolved measurements also allow us to explore the evolution of the neutral hydrogen density and temperature and effects of wall recycling. We find that the atomic neutral density grows rapidly at the initiation of the discharge, reaching the steady-state value within 1?ms. Additionally, we find that neutral hydrogen atoms are born with 0.08?eV temperatures, not 2?eV as is typically assumed.

Galante, M. E.; Magee, R. M.; Scime, E. E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)] [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)

2014-05-15T23:59:59.000Z

143

Planned waveguide electric field breakdown studies  

SciTech Connect (OSTI)

This paper presents an experimental setup for X-band rf breakdown studies. The setup is composed of a section of WR90 waveguide with a tapered pin located at the middle of the waveguide E-plane. Another pin is used to rf match the waveguide so it operates in a travelling wave mode. By adjusting the penetration depth of the tapered pin, different surface electric field enhancements can be obtained. The setup will be used to study the rf breakdown rate dependence on power flow in the waveguide for a constant maximum surface electric field on the pin. Two groups of pins have been designed. The Q of one group is different and very low. The other has a similar Q. With the test of the two groups of pins, we should be able to discern how the net power flow and Q affect the breakdown. Furthermore, we will apply an electron beam treatment to the pins to study its effect on breakdown. Overall, these experiments should be very helpful in understanding rf breakdown phenomena and could significantly benefit the design of high gradient accelerator structures.

Wang Faya; Li Zenghai [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

2012-12-21T23:59:59.000Z

144

Laser-induced dehydration of graphite oxide coatings on polymer substrates  

SciTech Connect (OSTI)

Nanosized graphite has been oxidized by the Hummers method to give high quality graphite oxide. This reaction is characterized by a very fast kinetic behavior and a high yield. The produced graphite oxide has been conveniently used to pattern graphene by using a standard photolithographic method, and the resulting systems have been characterized by optical microscopy (OM), scanning electron microscopy (SEM) and by Fourier transform infrared spectroscopy (FT-IR) and Visible-Near Infrared spectroscopy (Vis-NIR)

Longo, Angela, E-mail: angela.longo@cnr.it; Palomba, Mariano; Carotenuto, Gianfranco; Nicolais, Luigi [Institute for Composite and Biomedical Materials, National Research Council, Viale Kennedy, 54, Mostra d'Oltremare Padiglione 20, 80125 Napoli (Italy); Orabona, Emanuele; Maddalena, Pasqualino [Department of Physics, University of Naples, Federico II, via cintia, 80126, Naples, Italy and SPIN Institute, National Research Council, UOS Naples, via cintia, 80126, Naples (Italy); Ambrosio, Antonio [SPIN Institute, National Research Council, UOS Naples, via cintia, 80126, Naples (Italy)

2014-05-15T23:59:59.000Z

145

Thickness effect on laser-induced-damage threshold of indium-tin oxide films at 1064 nm  

SciTech Connect (OSTI)

Laser-induced-damage characteristics of commercial indium-tin oxide (ITO) films deposited by DC magnetron sputtering deposition on K9 glass substrates as a function of the film thickness have been studied at 1064 nm with a 10 ns laser pulse in the 1-on-1 mode, and the various mechanisms for thickness effect on laser-induced-damage threshold (LIDT) of the film have been discussed in detail. It is observed that laser-damage-resistance of ITO film shows dramatic thickness effect with the LIDT of the 50-nm ITO film 7.6 times as large as the value of 300 nm film, and the effect of depressed carrier density by decreasing the film thickness is demonstrated to be the primary reason. Our experiment findings indicate that searching transparent conductive oxide (TCO) film with low carrier density and high carrier mobility is an efficient technique to improve the laser-damage-resistance of TCO films based on maintaining their well electric conductivity.

Wang Haifeng; Huang Zhimeng; Zhang Dayong; Luo Fei; Huang Lixian; Li Yanglong; Luo Yongquan; Wang Weiping; Zhao Xiangjie [Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900 (China)

2011-12-01T23:59:59.000Z

146

Cost Codes and the Work Breakdown Structure  

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

The chapter discusses the purpose of the work breakdown structure (WBS) and code of account (COA) cost code system, shows the purpose and fundamental structure of both the WBS and the cost code system, and explains the interface between the two systems.

1997-03-28T23:59:59.000Z

147

THE JOURNAL OF CHEMICAL PHYSICS VOLUME 57, NUMBER 3 1 AUGUST 1972 Laser-Induced Fluorescence: A Method to Measure the Internal State Distribution of  

E-Print Network [OSTI]

THE JOURNAL OF CHEMICAL PHYSICS VOLUME 57, NUMBER 3 1 AUGUST 1972 Laser-Induced Fluorescence a pulsed (2-10 nsec duration), tunable dye laser3 passes through the reaction zone. As the wave- length 20 nsec the opening of the electronic gate. The BaO fluorescence rate versus laser wavelength

Zare, Richard N.

148

J. Chem. Soc., Perkin Trans. 2, 1997 1147 Laser-induced decompositions of 3,5-dimethyl-1,2,4-trioxolane  

E-Print Network [OSTI]

oligomerization occurring on the reactor walls. The multiple of the ArF laser induced photolytic products in the atmosphere is naturally of great interest, studies on their gas-phase thermal and photolytical decomposition radiation.4 We have recently studied the TEA CO2 laser-photosensitized (SF6) (homogeneous) decomposition

Haas, Yehuda

149

Time-synchronized continuous wave laser-induced fluorescence axial velocity measurements in a diverging cusped field thruster  

Science Journals Connector (OSTI)

Measurements are presented of time-synchronized axial ion velocities at three positions in the discharge channel and plume of a diverging cusped field thruster operating on xenon. Xenon axial ion velocities for the thruster are derived from laser-induced fluorescence measurements of the 5d[4]7/26p[3]5/2 xenon ion excited state transition centred at ?=834.72nm. The thruster is operated in a high-current mode, where the anode discharge current is shown to oscillate quasi-periodically. A sample-hold scheme is implemented to correlate ion velocities to phases along the current cycle. These time-synchronized measurements show that median axial ion velocities decrease as discharge current increases, and that the widths of ion velocity distributions increase with increases in discharge current for positions at the exit plane and outside the thruster channel.

N A MacDonald; M A Cappelli; W A Hargus Jr

2014-01-01T23:59:59.000Z

150

Prevention of breakdown behind railgun projectiles  

DOE Patents [OSTI]

An electromagnetic railgun accelerator system, for accelerating projectiles by a plasma arc, introduces a breakdown inhibiting gas into the railgun chamber behind the accelerating projectile. The breakdown inhibiting gas, which absorbs electrons, is a halide or a halide compound such as fluorine or SF[sub 6]. The gas is introduced between the railgun rails after the projectile has passed through inlets in the rails or the projectile; by coating the rails or the projectile with a material which releases the gas after the projectile passes over it; by fabricating the rails or the projectile or insulators out of a material which releases the gas into the portions of the chamber through which the projectile has travelled. The projectile may have a cavity at its rear to control the release of ablation products. 12 figs.

Hawke, R.S.

1992-10-13T23:59:59.000Z

151

Prevention of breakdown behind railgun projectiles  

DOE Patents [OSTI]

An electromagnetic railgun accelerator system, for accelerating projectiles by a plasma arc, introduces a breakdown inhibiting gas into the railgun chamber behind the accelerating projectile. The breakdown inhibiting gas, which absorbs electrons, is a halide or a halide compound such as fluorine or SF[sub 6]. The gas is introduced between the railgun rails after the projectile has passed through inlets in the rails or the projectile; by coating the rails or the projectile with a material which releases the gas after the projectile passes over it; by fabricating the rails or the projectile or insulators out of a material which releases the gas into the portions of the chamber through which the projectile has travelled. The projectile may have a cavity at its rear to control the release of ablation products. 12 figs.

Hawke, R.S.

1992-09-01T23:59:59.000Z

152

RF BREAKDOWN STUDIES USING PRESSURIZED CAVITIES  

SciTech Connect (OSTI)

Many present and future particle accelerators are limited by the maximum electric gradient and peak surface fields that can be realized in RF cavities. Despite considerable effort, a comprehensive theory of RF breakdown has not been achieved and mitigation techniques to improve practical maximum accelerating gradients have had only limited success. Part of the problem is that RF breakdown in an evacuated cavity involves a complex mixture of effects, which include the geometry, metallurgy, and surface preparation of the accelerating structures and the make-up and pressure of the residual gas in which plasmas form. Studies showed that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas, as needed for muon cooling channels, without the need for long conditioning times, even in the presence of strong external magnetic fields. This positive result was expected because the dense gas can practically eliminate dark currents and multipacting. In this project we used this high pressure technique to suppress effects of residual vacuum and geometry that are found in evacuated cavities in order to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. One of the interesting and useful outcomes of this project was the unanticipated collaborations with LANL and Fermilab that led to new insights as to the operation of evacuated normal-conducting RF cavities in high external magnetic fields. Other accomplishments included: (1) RF breakdown experiments to test the effects of SF6 dopant in H2 and He gases with Sn, Al, and Cu electrodes were carried out in an 805 MHz cavity and compared to calculations and computer simulations. The heavy corrosion caused by the SF6 components led to the suggestion that a small admixture of oxygen, instead of SF6, to the hydrogen would allow the same advantages without the corrosion in a practical muon beam line. (2) A 1.3 GHz RF test cell capable of operating both at high pressure and in vacuum with replaceable electrodes was designed, built, and power tested in preparation for testing the frequency and geometry effects of RF breakdown at Argonne National Lab. At the time of this report this cavity is still waiting for the 1.3 GHz klystron to be available at the Wakefield Test Facility. (3) Under a contract with Los Alamos National Lab, an 805 MHz RF test cavity, known as the All-Seasons Cavity (ASC), was designed and built by Muons, Inc. to operate either at high pressure or under vacuum. The LANL project to use the (ASC) was cancelled and the testing of the cavity has been continued under the grant reported on here using the Fermilab Mucool Test Area (MTA). The ASC is a true pillbox cavity that has performed under vacuum in high external magnetic field better than any other and has demonstrated that the high required accelerating gradients for many muon cooling beam line designs are possible. (4) Under ongoing support from the Muon Acceleration Program, microscopic surface analysis and computer simulations have been used to develop models of RF breakdown that apply to both pressurized and vacuum cavities. The understanding of RF breakdown will lead to better designs of RF cavities for many applications. An increase in the operating accelerating gradient, improved reliability and shorter conditioning times can generate very significant cost savings in many accelerator projects.

Johnson, Rolland

2014-09-21T23:59:59.000Z

153

Supercontinuum generation versus optical breakdown in CO2 gas  

Science Journals Connector (OSTI)

Threshold powers for optical breakdown (OB) and supercontinuum (SC) generation in high-pressure CO2 gas have been measured at different focusing conditions. It has been...

Ilkov, F A; Ilkova, L Sh; Chin, S L

1993-01-01T23:59:59.000Z

154

Spectroscopy and reactions of vibrationally excited transient molecules  

SciTech Connect (OSTI)

Spectroscopy, energy transfer and reactions of vibrationally excited transient molecules are studied through a combination of laser-based excitation techniques and efficient detection of emission from the energized molecules with frequency and time resolution. Specifically, a Time-resolved Fourier Transform Emission Spectroscopy technique has been developed for detecting dispersed laser-induced fluorescence in the IR, visible and UV regions. The structure and spectroscopy of the excited vibrational levels in the electronic ground state, as well as energy relaxation and reactions induced by specific vibronic excitations of a transient molecule can be characterized from time-resolved dispersed fluorescence in the visible and UV region. IR emissions from highly vibrational excited levels, on the other hand, reveal the pathways and rates of collision induced vibrational energy transfer.

Dai, H.L. [Univ. of Pennsylvania, Philadelphia (United States)

1993-12-01T23:59:59.000Z

155

Ultrafast laser induced electronic and structural modifications in bulk fused silica  

SciTech Connect (OSTI)

Ultrashort laser pulses can modify the inner structure of fused silica, generating refractive index changes varying from soft positive (type I) light guiding forms to negative (type II) values with void presence and anisotropic sub-wavelength modulation. We investigate electronic and structural material changes in the type I to type II transition via coherent and incoherent secondary light emission reflecting free carrier behavior and post-irradiation material relaxation in the index change patterns. Using phase contrast microscopy, photoluminescence, and Raman spectroscopy, we determine in a space-resolved manner defect formation, redistribution and spatial segregation, and glass network reorganization paths in conditions marking the changeover between type I and type II photoinscription regimes. We first show characteristic patterns of second harmonic generation in type I and type II traces, indicating the collective involvement of free carriers and polarization memory. Second, incoherent photoemission from resonantly and non-resonantly excited defect states reveals accumulation of non-bridging oxygen hole centers (NBOHCs) in positive index domains and oxygen deficiency centers (ODCs) with O{sub 2}{sup ?} ions segregation in void-like regions and in the nanostructured domains, reflecting the interaction strength. Complementary Raman investigations put into evidence signatures of the different environments where photo-chemical densification (bond rearrangements) and mechanical effects can be indicated. NBOHCs setting in before visible index changes serve as precursors for subsequent compaction build-up, indicating a scenario of cold, defect-assisted densification for the soft type I irradiation regime. Additionally, we observe hydrodynamic effects and severe bond-breaking in type II zones with indications of phase transition. These observations illuminate densification paths in fused silica in low power irradiation regimes, and equally in energetic ranges, characterized by the onset of thermo-mechanical effects.

Mishchik, K.; D'Amico, C.; Velpula, P. K.; Mauclair, C.; Boukenter, A.; Ouerdane, Y.; Stoian, R. [Laboratoire Hubert Curien, UMR 5516 CNRS, Universit de Lyon, Universit Jean Monnet, 42000 Saint Etienne (France)] [Laboratoire Hubert Curien, UMR 5516 CNRS, Universit de Lyon, Universit Jean Monnet, 42000 Saint Etienne (France)

2013-10-07T23:59:59.000Z

156

Laser-Induced Damage in Optical Materials 2001, Gregory J. Exarhos, Arthur H. Guenther, Keith L. Lewis, M. J. Soileau, Christopher J. Stolz, Editors, Proceedings of SPIE Vol. 4679 (2002)  

E-Print Network [OSTI]

Laser-Induced Damage in Optical Materials 2001, Gregory J. Exarhos, Arthur H. Guenther, Keith L. Lewis, M. J. Soileau, Christopher J. Stolz, Editors, Proceedings of SPIE Vol. 4679 (2002) © 2002 SPIE

Glebov, Leon

157

Note: Laser-induced acoustic desorption/synchrotron vacuum ultraviolet photoionization mass spectrometry for analysis of fragile compounds and heavy oils  

Science Journals Connector (OSTI)

In this work we coupled synchrotron vacuum ultraviolet photoionization (SVUV PI) method with the laser-induced acoustic desorption (LIAD) technique for mass spectrometric analysis. The LIAD technique is a soft desorption method which could avoid the degradation of analytes during desorption process. Meanwhile SVUV PI is an efficient soft ionization source. The new combination of the soft desorption technique and soft photoionization method is well suitable to reduce the difficulty for interpreting the mass spectra of the fragile compounds and heavy oils.

Liangyuan Jia; Junjie Weng; Zhongyue Zhou; Fei Qi; Wenyue Guo; Lianming Zhao; Juan Chen

2012-01-01T23:59:59.000Z

158

Laser-induced fluorescence measurements and kinetic analysis of Si atom formation in a rotating disk chemical vapor deposition reactor  

SciTech Connect (OSTI)

An extensive set of laser-induced fluorescence (LIF) measurements of Si atoms during the chemical vapor deposition (CVD) of silicon from silane and disilane in a research rotating disk reactor are presented. The experimental results are compared in detail with predictions from a numerical model of CVD from silane and disilane that treats the fluid flow coupled to gas-phase and gas-surface chemistry. The comparisons showed that the unimolecular decomposition of SiH[sub 2] could not account for the observed gas-phase Si atom density profiles. The H[sub 3]SiSiH [leftrightarrow] Si + SiH[sub 4] and H[sub 3]SiSiH + SiH[sub 2] [leftrightarrow] Si + Si[sub 2]H[sub 6] reactions are proposed as the primary Si atom production routes. The model is in good agreement with the measured shapes of the Si atom profiles and the trends in Si atom density with susceptor temperature, pressure, and reactant gas mixture. 33 refs., 12 figs., 3 tabs.

Ho, P.; Coltrin, M.E.; Breiland, W.G. (Sandia National Lab., Albuquerque, NM (United States))

1994-10-06T23:59:59.000Z

159

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

SciTech Connect (OSTI)

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

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

2006-11-15T23:59:59.000Z

160

Potential For Laser-Induced Microbunching Studies with the 3-MHZ-Rate Electron Beams at ASTA  

E-Print Network [OSTI]

Investigations of the laser-induced microbunching as it is related to time-sliced electron-beam diagnostics and high-gain-harmonic generation (HGHG) free-electron lasers using bright electron beams are proposed for the ASTA facility. Initial tests at 40-50 MeV with an amplified 800-nm seed laser beam co-propagating with the electron beam through a short undulator (or modulator) tuned for the resonance condition followed by transport through a subsequent chicane will result in energy modulation and z-density modulation (microbunching), respectively. The latter microbunching will result in generation of coherent optical or UV transition radiation (COTR, CUVTR) at a metal converter screen which can reveal slice beam size, centroid, and energy spread. Additionally, direct assessment of the microbunching factors related to HGHG by measurement of the COTR intensity and harmonic content after the chicane as a function of seed laser power and beam parameters will be done. These experiments will be performed using the...

Lumpkin, A H; Byrd, J M; Wilcox, R B

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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161

2-dimensional ion velocity distributions measured by laser-induced fluorescence above a radio-frequency biased silicon wafer  

SciTech Connect (OSTI)

The dynamics of ions traversing sheaths in low temperature plasmas are important to the formation of the ion energy distribution incident onto surfaces during microelectronics fabrication. Ion dynamics have been measured using laser-induced fluorescence (LIF) in the sheath above a 30 cm diameter, 2.2 MHz-biased silicon wafer in a commercial inductively coupled plasma processing reactor. The velocity distribution of argon ions was measured at thousands of positions above and radially along the surface of the wafer by utilizing a planar laser sheet from a pulsed, tunable dye laser. Velocities were measured both parallel and perpendicular to the wafer over an energy range of 0.4600 eV. The resulting fluorescence was recorded using a fast CCD camera, which provided resolution of 0.4 mm in space and 30 ns in time. Data were taken at eight different phases during the 2.2 MHz cycle. The ion velocity distributions (IVDs) in the sheath were found to be spatially non-uniform near the edge of the wafer and phase-dependent as a function of height. Several cm above the wafer the IVD is Maxwellian and independent of phase. Experimental results were compared with simulations. The experimental time-averaged ion energy distribution function as a function of height compare favorably with results from the computer model.

Moore, Nathaniel B.; Gekelman, Walter; Pribyl, Patrick [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States)] [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); Zhang, Yiting; Kushner, Mark J. [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109-2122 (United States)] [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109-2122 (United States)

2013-08-15T23:59:59.000Z

162

Laser-induced temperature jump/time-resolved infrared study of the fast events in protein folding  

SciTech Connect (OSTI)

Laser-induced temperature jump followed by time-resolved infrared probe of reaction dynamics are used to study the temporal evolution of polypeptide structure during protein folding and unfolding. Reactions are initiated in times of 50 ps or longer by T-jumps of 10`s of degrees, obtained by laser excitation of water overtone absorbances. Observation of the Amide I transient absorbances reveal melting lifetimes of helices unconstrained by tertiary structure to be ca. 160 ns in a model 21-peptide and ca. 30 ns in {open_quotes}molten globule{close_quotes} apomyoglobin. No other processes are observed in these systems over the timescale 50 ps to 2 ms. Equilibrium data suggest the corresponding helix formation lifetimes to be ca. 16 and 1 ns, respectively. In {open_quotes}native{close_quotes} apomyoglobin two helix melting lifetimes are observed and we infer that a third occurs on a timescale inaccessible to our experiment (> 1 ms). The shorter observed lifetime, as in the molten globule, is ca. 30 ns. The longer lifetime is ca. 70 {mu}s. We suggest that the slower process is helix melting that is rate-limited by the unfolding of tertiary structure. Equilibrium data suggest a lifetime of ca. 1 {mu}s for the development of these tertiary folds.

Woodruff, W.H.; Dyer, R.B.; Williams, S. [Los Alamos National Laboratory, NM (United States); Callender, H.; Gilmanshin, R. [CUNY, NY (United States)

1996-10-01T23:59:59.000Z

163

Time-resolved imaging of material response during laser-induced bulk damage in SiO2  

SciTech Connect (OSTI)

We report on time resolved imaging of the dynamic events taking place during laser-induced damage in the bulk of fused silica samples with nanosecond temporal resolution and one micron spatial resolution. These events include: shock/pressure wave formation and propagation, transient absorption, crack propagation and formation of residual stress fields. The work has been performed using a time-resolved microscope system that utilizes a probe pulse to acquire images at delay times covering the entire timeline of a damage event. Image information is enhanced using polarized illumination and simultaneously recording the two orthogonal polarization image components. For the case of fused silica, an electronic excitation is first observed accompanied by the onset of a pressure wave generation and propagation. Cracks are seen to form early in the process and reach their final size at about 25 ns into the damage event. In addition, changes that in part are attributed to transient absorption in the modified material are observed for delays up to about 200 microseconds.

Demos, S G; Negres, R A

2008-10-24T23:59:59.000Z

164

Optical contrast and laser-induced phase transition in GeCu{sub 2}Te{sub 3} thin film  

SciTech Connect (OSTI)

Fast crystallization and low power amorphization are essential to achieve rapid data recording and low power consumption in phase-change memory. This work investigated the laser-induced phase transition behaviors of GeCu{sub 2}Te{sub 3} film based on the reflectance of amorphous and crystalline states. The GeCu{sub 2}Te{sub 3} film showed a reflectance decrease upon crystallization, which was the opposite behavior in Ge{sub 2}Sb{sub 2}Te{sub 5} film. The crystallization starting time of the as-deposited GeCu{sub 2}Te{sub 3} film was as fast as that of the as-deposited Ge{sub 2}Sb{sub 2}Te{sub 5} film. Furthermore, the GeCu{sub 2}Te{sub 3} crystalline film was found to be reamorphized by laser irradiation at lower power and shorter pulse width than the Ge{sub 2}Sb{sub 2}Te{sub 5}.

Saito, Yuta; Sutou, Yuji; Koike, Junichi [Department of Materials Science, Tohoku University, 6-6-11-1016 Aoba-yama, Aoba-ku, Sendai 980-8579 (Japan)] [Department of Materials Science, Tohoku University, 6-6-11-1016 Aoba-yama, Aoba-ku, Sendai 980-8579 (Japan)

2013-02-04T23:59:59.000Z

165

Photo-Ionization and the Electrical Breakdown of Gases  

Science Journals Connector (OSTI)

25 June 1953 research-article Photo-Ionization and the Electrical Breakdown...theoretical investigation is made of the role of photo-ionization of the gas in the development...obtained experimentally. It is shown that photo-ionization can lead to electrical breakdown...

1953-01-01T23:59:59.000Z

166

Raman spectroscopy on Mars: identification of geological and bio-geological signatures in Martian analogues using miniaturized Raman spectrometers  

Science Journals Connector (OSTI)

...Department of Physics and Astronomy, Space Research Centre, University...with building spectrometers for space applications, including limited...Report. National Aeronautics and Space Administration. 77 Sharma...induced breakdown spectroscopy library for the Martian environment...

2014-01-01T23:59:59.000Z

167

Laser-induced heating of a multilayered medium resting on a half-space: Part 2 - Moving source  

SciTech Connect (OSTI)

Direct access storage devices (DASDs) are widely used in the computer industry to store and manage data. In conventional magnetic recording, an induction head flying very close to the disk surface alters the polarization of the magnetic field of the disk surface to erase and or write the information on the disk. However, a new technology known as magneto optical recording or optical recording has considerable promise to increase data densities and reliability of data source. In magneto-optical storage, magnetic fields are altered by a laser source, which heats the magnetic medium beyond its Curie point, a temperature at which the magnetic medium loses its magnetization. This domain with zero magnetization is subsequently reversed by using an induction magnet. All these processes take place when the disk is rotating at a very high speed with respect to the laser source. An optical disk is a multilayered medium consisting of a thick glass disk on which many layers of different materials are sputtered, only one layer of which serves as a magnetic medium. Therefore, in this paper, a problem of laser-induced heating of a multilayered medium resting on a half-space is considered when the laser is translation with respect to it. The transient heat conduction equation is solved by employing the Laplace transform in the time domain and the Fourier Transform in the x, y dimension. The resulting ordinary differential equation is solved and the inversion of the Lapplace transform is obtained by a technique developed by Crump. The Fourier inversion is obtained by using a Fast Fourier Transform. The technique developed here is then applied to calculate domain size for recorded bits for a given disk, laser power, source characteristics, and rotational velocity.

Kant, R.; Deckert, K.L. (IBM Research Div., San Jose, CA (USA))

1991-02-01T23:59:59.000Z

168

Soot particle sizing during high-pressure Diesel spray combustion via time-resolved laser-induced incandescence  

SciTech Connect (OSTI)

Single-pulse time-resolved laser-induced incandescence (TiRe-LII) signal transients from soot particulates were acquired during unsteady high pressure Diesel combustion in a constant volume cell for typical top dead center conditions during a Diesel engine cycle. Measurements were performed for initial gas pressures between 1 and 3 MPa, injection pressures between 50 and 130 MPa and laser probe timings between 5 and 16 ms after start of fuel injection. In separate experiments and for the same cell operating conditions gas temperatures were deduced from spectrally resolved soot pyrometry measurements. Implementing the LII model of Kock et al. [Combust. Flame 147 (2006) 79-92] ensemble mean soot particle diameters were evaluated from least-squares fitting of theoretical cooling curves to experimental TiRe-LII signal transients. Since in the experiments the environmental gas temperature and the width of an assumed particle size distribution were not known, the effects of the initial choice of these parameters on retrieved particle diameters were investigated. It is shown that evaluated mean particle diameters are only slightly biased by the choice of typical size distribution widths and gas temperatures. For a fixed combustion phase mean particle diameters are not much affected by gas pressure, however they become smaller at high fuel injection pressure. At a mean chamber pressure of 1.39 MPa evaluated mean particle diameters increased by a factor of two for probe delays between 5 and 16 ms after start of injection irrespective of the choices of first-guess fitting variables, indicating a certain robustness of data analysis procedure. (author)

Ryser, R.; Gerber, T.; Dreier, T. [Reaction Analysis Group, Department of General Energy, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)

2008-11-15T23:59:59.000Z

169

Soot particle sizing during high-pressure Diesel spray combustion via time-resolved laser-induced incandescence  

SciTech Connect (OSTI)

Single-pulse time-resolved laser-induced incandescence (TiRe-LII) signal transients from soot particulates were acquired during unsteady high pressure Diesel combustion in a constant volume cell for typical top dead center conditions during a Diesel engine cycle. Measurements were performed for initial gas pressures between 1 and 3 MPa, injection pressures between 50 and 130 MPa and laser probe timings between 5 and 16 ms after start of fuel injection. In separate experiments and for the same cell operating conditions gas temperatures were deduced from spectrally resolved soot pyrometry measurements. Implementing the LII model of Kock et al. [Combust. Flame 147 (20006) 79-92] ensemble mean soot particle diameters were evaluated from least-squares fitting of theoretical cooling curves to experimental TiRe-LII signal transients. Since in the experiments the environmental gas temperature and the width of an assumed particle size distribution were not known, the effects of the initial choice of these parameters on retrieved particle diameters were investigated. It is shown that evaluated mean particle diameters are only slightly biased by the choice of typical size distribution widths and gas temperatures. For a fixed combustion phase mean particle diameters are not much affected by gas pressure, however they become smaller at high fuel injection pressure. At a mean chamber pressure of 1.39 MPa evaluated mean particle diameters increased by a factor of two for probe delays between 5 and 16 ms after start of injection irrespective of the choices of first-guess fitting variables, indicating a certain robustness of data analysis procedure. (author)

Ryser, R.; Gerber, T.; Dreier, T. [Reaction Analysis Group, Department of General Energy, Paul Scherrer Institute, CH-5232 Villigen (Switzerland)

2009-01-15T23:59:59.000Z

170

Atmospheric-pressure gas breakdown from 2 to 100 MHz  

SciTech Connect (OSTI)

We report a detailed study of breakdown voltage of atmospheric-pressure helium gas between two parallel-plate electrodes from 2 to 100 MHz. Experimental data show that the breakdown voltage reduces initially with increasing frequency due to a diminishing contribution of drift-dominated electron wall loss and then begins to increase with increasing frequency. The latter is contrary to the current understanding that relies largely on the electron wall loss mechanism. Particle-in-cell simulation suggests that rapid oscillation of the applied voltage prevents electrons from reaching their maximum achievable kinetic energy, thus compromising the ionization efficiency and increasing the breakdown voltage.

Walsh, J. L.; Zhang, Y. T.; Iza, F.; Kong, M. G. [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)

2008-12-01T23:59:59.000Z

171

Understanding Sub-20nm Breakdown Behavior of Liquid Dielectrics  

Science Journals Connector (OSTI)

Nanoscale confinement of dielectric molecules is expected to influence their breakdown mechanism in applications such as nanoprobe based machining, molecular electronics, and other related technologies. This Letter presents the first experimental study of the breakdown of nonpolar, nonthiolated liquid dielectrics in the nanometer regime and develops a field emission assisted avalanche based approach to model such behavior. The studies show that dielectric breakdown in the sub-20nm regime is independent of the cathode materials and is dominated by the electron emission and atomic cluster migration due to the sub-20nm scale confinement of the liquid dielectric.

Kumar R. Virwani; Ajay P. Malshe; Kamlakar P. Rajurkar

2007-07-06T23:59:59.000Z

172

The Breakdown of Gases in High Frequency Electrical Fields  

Science Journals Connector (OSTI)

A theory is proposed to explain the mechanism of breakdown of gases in high frequency electrical fields. It is assumed that breakdown occurs when the electrical field and the frequency are such that an electron acquires the ionizing energy at the end of one mean free path. The field for breakdown is thus a function of the frequency of the applied potential and the ionization potential and pressure of the gas. The fields for breakdown of argon and xenon are calculated and expressed as functions of the frequency and the gas pressure. The calculated potentials are compared with experimental data, and good agreement is found for frequencies greater than 10106 c.p.s.

Donald H. Hale

1948-05-01T23:59:59.000Z

173

Breakdown Anodization (BDA) for hierarchical structures of titanium oxide  

E-Print Network [OSTI]

Breakdown Anodization (BDA) of titanium dioxide is a very promising, fast fabrication method to construct micro-scale and nano-scale structures on titanium surfaces. This method uses environmentally friendly electrolytes, ...

Choi, Soon Ju, S.M. Massachusetts Institute of Technology

2013-01-01T23:59:59.000Z

174

Studies of electrical breakdown processes across vacuum gaps between metallic electrodes  

E-Print Network [OSTI]

Studies of electrical breakdown processes across vacuum gaps between metallic electrodes L Keywords: Magnetic insulation Vacuum electrical breakdown Bacteria-induced electrical breakdown Accelerator a b s t r a c t An experimental program to elucidate the physical causes of electrical breakdown

Gilson, Erik

175

Laser induced nuclear reactions  

SciTech Connect (OSTI)

Dramatic improvements in laser technology since 1984 have revolutionised high power laser technology. Application of chirped-pulse amplification techniques has resulted in laser intensities in excess of 10{sup 19} W/cm{sup 2}. In the mid to late eighties, C. K. Rhodes and K. Boyer discussed the possibility of shining laser light of this intensity onto solid surfaces and to cause nuclear transitions. In particular, irradiation of a uranium target could induce electro- and photofission in the focal region of the laser. In this paper it is shown that {mu}Ci of {sup 62}Cu can be generated via the ({gamma},n) reaction by a laser with an intensity of about 10{sup 19} Wcm{sup -2}.

Ledingham, Ken; McCanny, Tom; Graham, Paul; Fang Xiao; Singhal, Ravi; Magill, Joe; Creswell, Alan; Sanderson, David; Allott, Ric; Neely, David; Norreys, Peter; Santala, Marko; Zepf, Matthew; Watts, Ian; Clark, Eugene; Krushelnick, Karl; Tatarakis, Michael; Dangor, Bucker; Machecek, Antonin; Wark, Justin [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland (United Kingdom); European Commission, Institute for Transuranic Elements, Karlsruhe, Postfach 2340, D-76125 (Germany); Scottish Universities Research and Reactor Centre, East Kilbride, Glasgow G75 0QU (United Kingdom); Rutherford Appleton Laboratory, Chilton, Didcot (United Kingdom); Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom); Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU (United Kingdom)

1998-12-16T23:59:59.000Z

176

The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals  

SciTech Connect (OSTI)

High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer. Of particular interest are the roles IO plays in the formation of new particles in coastal marine environments and in depletion episodes of ozone and mercury in the Arctic polar spring. This paper describes a ground-based instrument that measures IO at mixing ratios less than one part in 10{sup 12}. The IO radical is measured by detecting laser-induced fluorescence at wavelengths longer that 500 nm. Tunable visible light is used to pump the A{sup 2}?{sub 3/2} (v{sup ?} = 2) ? X{sup 2}?{sub 3/2} (v{sup ?} = 0) transition of IO near 445 nm. The laser light is produced by a solid-state, Nd:YAG-pumped Ti:Sapphire laser at 5 kHz repetition rate. The laser-induced fluorescence instrument performs reliably with very high signal-to-noise ratios (>10) achieved in short integration times (<1 min). The observations from a validation deployment to the Shoals Marine Lab on Appledore Island, ME are presented and are broadly consistent with in situ observations from European Coastal Sites. Mixing ratios ranged from the instrumental detection limit (<1 pptv) to 10 pptv. These data represent the first in situ point measurements of IO in North America.

Thurlow, M. E., E-mail: thurlow@huarp.harvard.edu; Hannun, R. A.; Lapson, L. B.; Anderson, J. G. [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States)] [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States); Co, D. T. [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States) [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States); Argonne-Northwestern Solar Energy Research Center and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113 (United States); O'Brien, A. S. [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States) [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States); Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Hanisco, T. F. [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States) [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States); NASA Goddard Space Flight Center, Code 614, Greenbelt, Maryland 20771 (United States)

2014-04-15T23:59:59.000Z

177

Spectroscopic temperature measurements of air breakdown plasma using a 110 GHz megawatt gyrotron beam  

SciTech Connect (OSTI)

Temperature measurements are presented of a non-equilibrium air breakdown plasma using optical emission spectroscopy. A plasma is created with a focused 110 GHz 3 {mu}s pulse gyrotron beam in air that produces power fluxes exceeding 1 MW/cm{sup 2}. Rotational and vibrational temperatures are spectroscopically measured over a pressure range of 1-100 Torr as the gyrotron power is varied above threshold. The temperature dependence on microwave field as well as pressure is examined. Rotational temperature measurements of the plasma reveal gas temperatures in the range of 300-500 K and vibrational temperatures in the range of 4200-6200 K. The vibrational and rotational temperatures increase slowly with increasing applied microwave field over the range of microwave fields investigated.

Hummelt, J. S.; Shapiro, M. A.; Temkin, R. J. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2012-12-15T23:59:59.000Z

178

Interferometric investigation of optical breakdown in air at  

Science Journals Connector (OSTI)

An investigation was made of the thermal processes which accompany optical breakdown in air at the surface of a metallic target. A titanium target was subjected to radiation of power density ~0.3 MW/cm2 from a CO2 gas-discharge laser, for a period of ~ 1 msec. The use of interferometric diagnostics having adequate spatial and temporal resolution (~300 ? and ~30 usec) made it possible to describe the heating of the air at the target surface before breakdown, the formation and propagation of the breakdown plasma, the absorption of laser radiation in it, and the heating of the air by the plasma. Estimates were made of the plasma parameters.

A V Bondarenko; V P Voronina; I I Gorodnicheva; E V Dan'shchikov; A I Zakharchenko; F V Lebedev; A V Ryazanov; M M Smakotin

1980-01-01T23:59:59.000Z

179

MHK Cost Breakdown Structure Draft | OpenEI Community  

Open Energy Info (EERE)

MHK Cost Breakdown Structure Draft MHK Cost Breakdown Structure Draft Home > Groups > Water Power Forum Kch's picture Submitted by Kch(24) Member 9 April, 2013 - 13:30 CBS current energy GMREC LCOE levelized cost of energy marine energy MHK ocean energy The generalized Cost Breakdown Structure (CBS) for marine and hydrokinetic (MHK) projects is a hierarchical structure designed to facilitate the collection and organization of lifecycle costs of any type of MHK project, including wave energy converters and current energy convertners. At a high level, the categories in the CBS will be applicable to all projects; at a detailed level, however, the CBS includes many cost categories that will pertain to one project but not others. It is expected that many of the detailed levels of the CBS will be populated with "NA" or left blank.

180

EMSL - spectroscopy  

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

spectroscopy en Behavior of nanoceria in biologically-relevant environments. http:www.emsl.pnl.govemslwebpublicationsbehavior-nanoceria-biologically-relevant-environments

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


181

The effect of pulse duration on the growth rate of laser-induced damage sites at 351 nm on fused silica surfaces  

SciTech Connect (OSTI)

Past work in the area of laser-induced damage growth has shown growth rates to be primarily dependent on the laser fluence and wavelength. More recent studies suggest that growth rate, similar to the damage initiation process, is affected by a number of additional parameters including pulse duration, pulse shape, site size, and internal structure. In this study, we focus on the effect of pulse duration on the growth rate of laser damage sites located on the exit surface of fused silica optics. Our results demonstrate, for the first time, a significant dependence of growth rate at 351 nm on pulse duration from 1 ns to 15 ns as {tau}{sup 0.3} for sites in the 50-100 {micro}m size range.

Negres, R A; Norton, M A; Liao, Z M; Cross, D A; Bude, J D; Carr, C W

2009-10-29T23:59:59.000Z

182

Corrosion inhibitor storage and release property of TiO{sub 2} nanotube powder synthesized by rapid breakdown anodization method  

SciTech Connect (OSTI)

Graphical abstract: Display Omitted Highlights: ? TiO{sub 2} nanotube powders were synthesized by rapid breakdown anodization method. ? Benzotriazole was loaded into the TiO{sub 2} nanotube powders. ? Low pH induced release of benzotriazole from TiO{sub 2} nanotube powders was proved. -- Abstract: Titanium dioxide (TiO{sub 2}) is one of the most studied substances in material science due to its versatile properties and diverse applications. In this study titanium dioxide nanotube powder were synthesized by rapid breakdown anodization (RBA) method. The synthesis involved potentiostatic anodization of titanium foil in 0.1 M HClO{sub 4} electrolyte under an applied voltage of 20 V and rapid stirring. The morphology and the phase of titanium dioxide nanotube powder were studied using field emission scanning electron microscopy, laser Raman spectroscopy and high resolution transmission electron microscopy. Benzotriazole was chosen as model inhibitor to evaluate TiO{sub 2} nanotube powder's corrosion inhibitor loading and releasing properties. The storage and release properties of TiO{sub 2} nanotube powder were studied using UVvisible spectroscopy and thermogravimetric analysis.

Arunchandran, C.; Ramya, S.; George, R.P. [Corrosion Science and Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)] [Corrosion Science and Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Kamachi Mudali, U., E-mail: kamachi@igcar.gov.in [Corrosion Science and Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

2013-02-15T23:59:59.000Z

183

Nuclear Envelope Breakdown Can Substitute for Primary Envelopment-Mediated Nuclear Egress of Herpesviruses  

Science Journals Connector (OSTI)

...15 August 2011 research-article Structure and Assembly Nuclear Envelope Breakdown...herpesvirus-induced nuclear envelope breakdown...Journal Article Research Support, Non-U...Microscopy, Electron Nuclear Envelope metabolism...

Barbara G. Klupp; Harald Granzow; Thomas C. Mettenleiter

2011-06-15T23:59:59.000Z

184

Comparison of optical emission from nanosecond and femtosecond laser produced plasma in atmosphere and vacuum conditions  

E-Print Network [OSTI]

Comparison of optical emission from nanosecond and femtosecond laser produced plasma in atmosphere Laser-induced breakdown spectroscopy Laser-produced plasma Plasma dynamics Femtosecond laser ablation In this study we examine the emission from brass plasma produced by ns and fs laser ablation under both vacuum

Harilal, S. S.

185

APPROXIMATE SOLUTION OF A CLASS OF QUEUEING NETWORKS WITH BREAKDOWNS  

E-Print Network [OSTI]

breakdowns and are subsequently repaired. The network topology is a pipeline with feedback from the final of operational servers at each node in the pipeline. This model is in general intractable, however an iterative], but changed the nature of the fail- ure so that queues were preserved during repair peri- ods. The same

Imperial College, London

186

Initial breakdown pulses in intracloud lightning flashes and their relation to terrestrial gamma ray flashes  

E-Print Network [OSTI]

Initial breakdown pulses in intracloud lightning flashes and their relation to terrestrial gamma breakdown stage of 10 intracloud lightning flashes that may have produced terrestrial gamma ray flashes, and S. Xiong (2013), Initial breakdown pulses in intracloud lightning flashes and their relation

Cummer, Steven A.

187

Studies of electrical breakdown processes across vacuum gaps between metallic electrodes  

E-Print Network [OSTI]

Studies of electrical breakdown processes across vacuum gaps between metallic electrodes L Available online 3 June 2013 Keywords: Magnetic insulation Vacuum electrical breakdown Bacteria-induced electrical breakdown Accelerator a b s t r a c t An experimental program to elucidate the physical causes

Gilson, Erik

188

Fundamental studies in the molecular basis of laser-induced retinal damage. Annual report, February-September 1981  

SciTech Connect (OSTI)

Laser-spectroscopy experiments have focused on cones in the red-eared swamp turtle, Pseudemys scripta elegans. Choice of this system was based on the desire to correlate molecular data with the extensive data being collected on this system by Dr. Zwick in his studies on laser hazards at LAIR. Thus, a detailed collaborative effort was initiated on this system during the past year. The experiments resulted in important information that opens new avenues to explore fundamental molecular mechanisms of retinal damage with laser irradiation. Results of these experiments are summarized in the following sections: I. Elucidation of the role of oil droplets in the absorption of light by the turtle retina; II. A Selective Probe of Membrane Potentials in Turtle Cone Cells; III. Angstrom Resolution Light Microscopy of Photoreceptor Cells; IV. Identification and Selective Staining of Other Important Molecular Components of Photoreceptor Cells.

Lewis

1981-09-01T23:59:59.000Z

189

Gas breakdown in an atmospheric pressure radio-frequency capacitive plasma source  

Science Journals Connector (OSTI)

Gas breakdown is studied in an atmospheric pressure rf capacitive plasma source developed for materials applications. At a rf frequency of 13.56 MHz breakdown voltage is largely a function of the product of the pressure and the discharge gap spacing approximating the Paschen curve. However breakdown voltage varies substantially with rf frequency due to a change in the electron loss mechanism. A large increase in breakdown voltage is observed when argon oxygen or nitrogen is added to helium despite their lower ionization potential. Discussion is given for optimal breakdown conditions at atmospheric pressure.

Jaeyoung Park; I. Henins; H. W. Herrmann; G. S. Selwyn

2001-01-01T23:59:59.000Z

190

Detecting excess ionizing radiation by electromagnetic breakdown of air  

SciTech Connect (OSTI)

A scheme is proposed for detecting a concealed source of ionizing radiation by observing the occurrence of breakdown in atmospheric air by an electromagnetic wave whose electric field surpasses the breakdown field in a limited volume. The volume is chosen to be smaller than the reciprocal of the naturally occurring concentration of free electrons. The pulse duration of the electromagnetic wave must exceed the avalanche breakdown time (10-200 ns) and could profitably be as long as the statistical lag time in ambient air (typically, microseconds). Candidate pulsed electromagnetic sources over a wavelength range, 3 mm>{lambda}>10.6 {mu}m, are evaluated. Suitable candidate sources are found to be a 670 GHz gyrotron oscillator with 200 kW, 10 {mu}s output pulses and a Transversely Excited Atmospheric-Pressure (TEA) CO{sub 2} laser with 30 MW, 100 ns output pulses. A system based on 670 GHz gyrotron would have superior sensitivity. A system based on the TEA CO{sub 2} laser could have a longer range >100 m.

Granatstein, Victor L.; Nusinovich, Gregory S. [Center for Applied Electromagnetics, Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States)

2010-09-15T23:59:59.000Z

191

 

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

Analytical Development uses class III and IV high power lasers for numerous spectroscopy applications including Laser Induced Breakdown Analytical Development uses class III and IV high power lasers for numerous spectroscopy applications including Laser Induced Breakdown Spectroscopy (LIBS), Laser Ablation methods, Raman Spectroscopy, and several particle sizing and light scattering applications. To support the setup, staging, and maintenance of these systems, AD occupies labs 147 & 148 in 999-2W (& lab C143/147 in 773A). These labs have optical benches, laser warning lights, and door and window curtains for blocking open beam laser emissions. In addition, the instrumentation is usually made mobile or portable for field application where open beam is not allowed. This EEC covers general set-up, maintenance and troubleshooting of laser spectroscopy within Analytical Development. Set-up includes placement of lasers systems within proper laser controlled environments, mirror and lens placement

192

 

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

Analytical Development uses class III and IV high power lasers for numerous spectroscopy applications including Laser Induced Breakdown Analytical Development uses class III and IV high power lasers for numerous spectroscopy applications including Laser Induced Breakdown Spectroscopy (LIBS), Laser Ablation methods, Raman Spectroscopy, and several particle sizing and light scattering applications. To support the setup, staging, and maintenance of these systems, AD occupies labs 147 & 148 in 999-2W (& lab C143/147 in 773A). These labs have optical benches, laser warning lights, and door and window curtains for blocking open beam laser emissions. In addition, the instrumentation is usually made mobile or portable for field application where open beam is not allowed. This EEC covers general set-up, maintenance and troubleshooting of laser spectroscopy within Analytical Development. Set-up includes placement of lasers systems within proper laser controlled environments, mirror and lens

193

Borehole breakdown pressure with drilling fluidsI. Empirical results  

Science Journals Connector (OSTI)

Mining and civil engineering industries sometimes use drilling muds for stabilizing a borehole during drilling wells for methane drainage, geothermal energy and radioactive waste disposal. Standard theories predicting borehole breakdown pressure assume breakdown occurs when a small fracture initiates at a location where the largest tangential stress at the borehole reaches the tensile strength of formation. Fracturing tests conducted in this study, however, showed that when drilling fluid was used as an injection fluid, borehole breakdown did not occur even if a fracture initiated at a borehole wall. Borehole breakdown occurred when the initiated fracture became unstable after significant growth [with 0.76 cm (0.3 in.) to 7.62 cm (3 in.) in length]. The test results showed that all drilling muds had a tendency to seal narrow natural fractures or fractures induced by high borehole pressure. The sealing effect of the mud stabilized fractures and prevented fracture propagation. This effect is one of the primary factors for controlling wellbore stability. In this work [1], more than 40 large rock samples [76.2 76.2 76.2 cm (30 30 30 in.)] were fractured to test the drilling fluid effect on fracture initiation and fracture propagation around a borehole. The results show that borehole breakdown pressure is highly dependent on the Young's modulus of the formation, wellbore size and type of the drilling fluids. Note that the conventional linear wellbore stability theory has ignored all these facts. The results of this experiment are intended to apply to the lost circulation problems from an induced fracture or to the interpretation of the in situ stress measurements with gelled fluids where drilling or fracturing fluids contain significant amount of solid components. Similar phenomena occur for the standard hydraulic fracturing fluids; however, the process zone and the high flow friction at the narrow fracture tip become as important as the gel and solid plugging effect shown in this paper. Hence, the results should be modified before being applied to standard fracturing fluids.

N. Morita; A.D. Black; G.-F. Fuh

1996-01-01T23:59:59.000Z

194

Characterization of nonpolar lipids and steroids by using laser-induced acoustic desorption/chemical ionization, atmospheric pressure chemical ionization, and electrospray ionization mass spectrometry  

SciTech Connect (OSTI)

Laser-induced acoustic desorption (LIAD) combined with ClMn(H{sub 2}O){sup +} chemical ionization (CI) was tested for the analysis of nonpolar lipids and selected steroids in a Fourier-transform ion cyclotron resonance mass spectrometer (FT-ICR). The nonpolar lipids studied, cholesterol, 5?-cholestane, cholesta-3,5-diene, squalene, and ?-carotene, were found to solely form the desired water replacement product (adduct-H{sub 2}O) upon reaction with the ClMn(H{sub 2}O){sup +} ions. The steroids, androsterone, dehydroepiandrosterone (DHEA), estrone, estradiol, and estriol, also form abundant adduct-H{sub 2}O ions, but less abundant adduct-2H{sub 2}O ions were also observed. Neither (+)APCI nor (+)ESI can ionize the saturated hydrocarbon lipid, cholestane. APCI successfully ionizes the unsaturated hydrocarbon lipids to form exclusively the intact protonated analytes. However, it causes extensive fragmentation for cholesterol and the steroids. The worst case is cholesterol that does not produce any stable protonated molecules. On the other hand, ESI cannot ionize any of the hydrocarbon analytes, saturated or unsaturated. However, ESI can be used to protonate the oxygen-containing analytes with substantially less fragmentation than for APCI in all cases except for cholesterol and estrone. In conclusion, LIAD/ClMn(H{sub 2}O){sup +} chemical ionization is superior over APCI and ESI for the mass spectrometric characterization of underivatized nonpolar lipids and steroids.

Jin, Z.; Daiya, S.; Kenttmaa, Hilkka I.

2011-01-01T23:59:59.000Z

195

Using Gold Nanoparticles as Artificial Defects in Thin Films: What Have We Learned About Laser-Induced Damage Driven by Localized Absorbers?  

SciTech Connect (OSTI)

There is general agreement that localized absorbing defects are a major factor affecting thin-film performance, and laser-induced damage in films designed for UV, nanosecond-scale, pulsed-laser applications is driven by nanoscale absorbers. Low number densities and size (few nanometer), however, prevent any characterization of these defects and, consequently, deterministic film improvement. This situation also hampers further development of localized defect-driven damage theory, since initial conditions for modeling remain uncertain. Recently, a new approach for studying laser interaction with thin-film nanoscale defects was implemented in which well-characterized, isolated artificial absorbing defects (gold nanoparticles) were introduced inside the thin film. This work is a review in which we discuss main findings from experiments with gold nanoparticles, such as delocalization of absorption during the laser pulse, importance of the defect boundary conditions (contact with the matrix), and competition of pure thermal and stress-driven mechanisms of damage-crater formation. These experimental results will be compared with theoretical results of damage-crater formation in such model thin films using both phenomenological modeling and detailed calculations of the kinetics of the damage process. An outlook on future thin-film-damage studies using model systems with artificial defects is also presented.

Papernov, S.; Schmid, A.W.

2007-03-14T23:59:59.000Z

196

Vehicle Technologies Office: Fact #526: July 7, 2008 Price Breakdown for a  

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

6: July 7, 2008 6: July 7, 2008 Price Breakdown for a Gallon of Gasoline and a Gallon of Diesel to someone by E-mail Share Vehicle Technologies Office: Fact #526: July 7, 2008 Price Breakdown for a Gallon of Gasoline and a Gallon of Diesel on Facebook Tweet about Vehicle Technologies Office: Fact #526: July 7, 2008 Price Breakdown for a Gallon of Gasoline and a Gallon of Diesel on Twitter Bookmark Vehicle Technologies Office: Fact #526: July 7, 2008 Price Breakdown for a Gallon of Gasoline and a Gallon of Diesel on Google Bookmark Vehicle Technologies Office: Fact #526: July 7, 2008 Price Breakdown for a Gallon of Gasoline and a Gallon of Diesel on Delicious Rank Vehicle Technologies Office: Fact #526: July 7, 2008 Price Breakdown for a Gallon of Gasoline and a Gallon of Diesel on Digg

197

PHENIX Work Breakdown Structure. Cost and schedule review copy  

SciTech Connect (OSTI)

The Work Breakdown Structure (WBS) Book begins with this Overview section, which contains the high-level summary cost estimate, the cost profile, and the global construction schedule. The summary cost estimate shows the total US cost and the cost in terms of PHENIX construction funds for building the PHENIX detector. All costs in the WBS book are shown in FY 1993 dollars. Also shown are the institutional and foreign contributions, the level of pre-operations funding, and the cost of deferred items. Pie charts are presented at PHENIX WBS level 1 and 2 that show this information. The PHENIX construction funds are shown broken down to PHENIX WBS level 3 items per fiscal year, and the resulting profile is compared to the RHIC target profile. An accumulated difference of the two profiles is also shown. The PHENIX global construction schedule is presented at the end of the Overview section. Following the Overview are sections for each subsystem. Each subsystem section begins with a summary cost estimate, cost profile, and critical path. The total level 3 cost is broken down into fixed costs (M&S), engineering costs (EDIA) and labor costs. Costs are further broken down in terms of PHENIX construction funds, institutional and foreign contributions, pre-operations funding, and deferred items. Also shown is the contingency at level 3 and the level 4 breakdown of the total cost. The cost profile in fiscal years is shown at level 3. The subsystem summaries are followed by the full cost estimate and schedule sheets for that subsystem. These detailed sheets are typically carried down to level 7 or 8. The cost estimate shows Total, M&S, EDIA, and Labor breakdowns, as well as contingency, for each WBS entry.

Not Available

1994-02-01T23:59:59.000Z

198

Asymmetric Bimodal Accelerator Cavity for Raising rf Breakdown Thresholds  

SciTech Connect (OSTI)

We consider an axisymmetric microwave cavity for an accelerator structure whose eigenfrequency for its second lowest TM-like axisymmetric mode is twice that of the lowest such mode, and for which the fields are asymmetric along its axis. In this cavity, the peak amplitude of the rf electric field that points into either longitudinal face can be smaller than the peak field which points out. Computations show that a structure using such cavities might support an accelerating gradient about 47% greater than that for a structure using similar single-mode cavities, without an increase in breakdown probability.

Kuzikov, S. V. [Omega-P, Inc., 258 Bradley Street, New Haven, Connecticut 06510 (United States); Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov Street, Nizhny Novgorod, 603950 (Russian Federation); Kazakov, S. Yu. [Omega-P, Inc., 258 Bradley Street, New Haven, Connecticut 06510 (United States); Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Jiang, Y. [Physics Department, Yale University, New Haven, Connecticut 06520-8120 (United States); Hirshfield, J. L. [Omega-P, Inc., 258 Bradley Street, New Haven, Connecticut 06510 (United States); Physics Department, Yale University, New Haven, Connecticut 06520-8120 (United States)

2010-05-28T23:59:59.000Z

199

Breakdown of the Dipole Approximation in Strong-Field Ionization  

E-Print Network [OSTI]

We report the breakdown of the electric dipole approximation in the long-wavelength limit in strong-field ionization with linearly polarized few-cycle mid-infrared laser pulses at intensities on the order of 10$^{13}$ W/cm$^2$. Photoelectron momentum distributions were recorded by velocity map imaging and projected onto the beam propagation axis. We observe an increasing shift of the peak of this projection opposite to the beam propagation direction with increasing laser intensities. From a comparison with semi-classical simulations, we identify the combined action of the magnetic field of the laser pulse and the Coulomb potential as origin of our observations.

Ludwig, A; Mayer, B W; Phillips, C R; Gallmann, L; Keller, U

2014-01-01T23:59:59.000Z

200

Breakdown of the Dipole Approximation in Strong-Field Ionization  

E-Print Network [OSTI]

We report the breakdown of the electric dipole approximation in the long-wavelength limit in strong-field ionization with linearly polarized few-cycle mid-infrared laser pulses at intensities on the order of 10$^{13}$ W/cm$^2$. Photoelectron momentum distributions were recorded by velocity map imaging and projected onto the beam propagation axis. We observe an increasing shift of the peak of this projection opposite to the beam propagation direction with increasing laser intensities. From a comparison with semi-classical simulations, we identify the combined action of the magnetic field of the laser pulse and the Coulomb potential as origin of our observations.

A. Ludwig; J. Maurer; B. W. Mayer; C. R. Phillips; L. Gallmann; U. Keller

2014-08-11T23:59:59.000Z

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


201

Kinetic modeling of the Townsend breakdown in argon  

SciTech Connect (OSTI)

Kinetic modeling of the Townsend breakdown in argon was performed in the forward-back approximation. The kinetic model was found to adequately describe the left branch of the Paschen curve, and the important role of ionization by fast ions and atoms near the cathode, as well as the increase in secondary emission coefficient in strong electric fields described in the literature, was confirmed. The modeling also showed that the electron energy distribution function develops a beam of high-energy electrons and that the runaway effect, i.e., the monotonic increase of the mean electron energy with the distance from the cathode, occurs at the left branch of the Paschen curve.

Macheret, S. O.; Shneider, M. N. [Department of Mechanical and Aerospace Engineering, Princeton University, D-414 Engineering Quadrangle, Princeton, New Jersey 08544 (United States)] [Department of Mechanical and Aerospace Engineering, Princeton University, D-414 Engineering Quadrangle, Princeton, New Jersey 08544 (United States)

2013-10-15T23:59:59.000Z

202

Gas breakdown driven by L band short-pulse high-power microwave  

SciTech Connect (OSTI)

High power microwave (HPM) driven gas breakdown is a major factor in limiting the radiation and transmission of HPM. A method that HPM driven gas breakdown could be obtained by changing the aperture of horn antenna is studied in this paper. Changing the effective aperture of horn antenna can adjust the electric field in near field zone, leading to gas breakdown. With this method, measurements of air and SF{sub 6} breakdowns are carried out on a magnetically insulated transmission-line oscillators, which is capable of generating HPM with pulse duration of 30 ns, and frequency of 1.74 GHz. The typical breakdown waveforms of air and SF{sub 6} are presented. Besides, the breakdown field strengths of the two gases are derived at different pressures. It is found that the effects of air and SF{sub 6} breakdown on the transmission of HPM are different: air breakdown mainly shortens the pulse width of HPM while SF{sub 6} breakdown mainly reduces the peak output power of HPM. The electric field threshold of SF{sub 6} is about 2.4 times larger than that of air. These differences suggest that gas properties have a great effect on the transmission characteristic of HPM in gases.

Yang Yiming; Yuan Chengwei; Qian Baoliang [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2012-12-15T23:59:59.000Z

203

Electrical breakdown of a bubble in a water-filled capillary  

SciTech Connect (OSTI)

In this Communication, the electrical breakdown of a static bubble in a water-filled capillary generated in a dc electrical field is studied. We present experimental results which indicate that the liquid layer between capillary and bubble wall can have an important influence on the breakdown mechanism of the bubble. The breakdown electrical field (atmospheric pressure) without a liquid layer in a (vapor) bubble is 18 kV/cm. When a liquid layer is present, the electrical breakdown of an air bubble is observed at electrical fields typically two times smaller. Local plasma formation is observed in this case possibly due to bubble deformation.

Bruggeman, P.J.; Leys, C.A.; Vierendeels, J. A. [Department of Applied Physics, Research Unit Plasma Technology (RUPT), Faculty of Engineering, Ghent University, Rozier 44, B-9000 Ghent (Belgium); Department of Flow, Heat and Combustion Mechanics, Faculty of Engineering, Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Ghent (Belgium)

2006-06-01T23:59:59.000Z

204

A time-resolved laser induced fluorescence study on the ion velocity distribution function in a Hall thruster after a fast current disruption  

SciTech Connect (OSTI)

The temporal characteristics of the Xe{sup +} ion axial velocity distribution function (VDF) were recorded in the course of low-frequency discharge current oscillations ({approx}14 kHz) of the 5 kW class PPS X000 Hall thruster. The evolution in time of the ion axial velocity component is monitored by means of a laser induced fluorescence diagnostic tool with a time resolution of 100 ns. As the number of fluorescence photons is very low during such a short time period, a homemade pulse-counting lock-in system was used to perform real-time discrimination between background photons and fluorescence photons. The evolution in time of the ion VDF was observed at three locations along the thruster channel axis after a fast shutdown of the thruster power. The anode discharge current is switched off at 2 kHz during 5 {mu}s without any synchronization with the current oscillation cycle. This approach allows to examine the temporal behavior of the ion VDF during decay and ignition of the discharge as well as during forced and natural plasma oscillations. Measurements show that the distribution function of the axial component of the Xe{sup +} ion does change periodically in time with a frequency close to the current oscillation frequency in both forced and natural cases. The ion density and the mean velocity are found to oscillate, whereas the velocity dispersion stays constant, which indicates that ionization and acceleration layers have identical dynamics. Finally, variations over time in the electric field are for the first time experimentally evidenced in a crossed-field discharge.

Mazouffre, S.; Gawron, D. [ICARE, CNRS, 1C avenue de la Recherche Scientifique, 45071 Orleans (France); Sadeghi, N. [LSP, Joseph Fourier University, CNRS, 140 Av. de la Physique, 38402 St. Martin d'Hueres (France)

2009-04-15T23:59:59.000Z

205

Detecting excess ionizing radiation by electromagnetic breakdown of air  

Science Journals Connector (OSTI)

A scheme is proposed for detecting a concealed source of ionizing radiation by observing the occurrence of breakdown in atmospheric air by an electromagnetic wave whose electric field surpasses the breakdown field in a limited volume. The volume is chosen to be smaller than the reciprocal of the naturally occurring concentration of free electrons. The pulse duration of the electromagnetic wave must exceed the avalanchebreakdown time (10200 ns) and could profitably be as long as the statistical lag time in ambient air (typically microseconds). Candidate pulsed electromagnetic sources over a wavelength range 3 ? mm > ? > 10.6 ? ? m are evaluated. Suitable candidate sources are found to be a 670 GHz gyrotron oscillator with 200 kW 10 ? ? s output pulses and a Transversely Excited Atmospheric-Pressure (TEA) CO 2 laser with 30 MW 100 ns output pulses. A system based on 670 GHz gyrotron would have superior sensitivity. A system based on the TEA CO 2 laser could have a longer range > 100 ? m .

Victor L. Granatstein; Gregory S. Nusinovich

2010-01-01T23:59:59.000Z

206

Isotope effects and Born-Oppenheimer breakdown in excited singlet states of the lithium dimer  

E-Print Network [OSTI]

Isotope effects and Born-Oppenheimer breakdown in excited singlet states of the lithium dimer A of infrared electronic transitions involving the 1 1 g state of 7 Li2 has instigated an investigation of Born-Oppenheimer and the leading vibrational and/or rotational Born-Oppenheimer breakdown terms for the X 1 g , A 1 u , B 1 u

Le Roy, Robert J.

207

Electron transfer through time dependent bridges: Differences between FranckCondon and BornOppenheimer breakdown  

Science Journals Connector (OSTI)

We consider tunneling-mediated electron transfer through time dependent bridges. An approach is developed for computing corrections to the time dependent tunneling matrix element that arise from the breakdown of the BornOppenheimer Adiabatic approximation. Differences between FranckCondon and BornOppenheimer breakdown are discussed in the context of bridge-mediated tunneling.

Antonios Teklos; Spiros S. Skourtis

2005-01-01T23:59:59.000Z

208

Wiedenhfer et al. Inter-Organizational Crisis Management Infrastructure for Electrical Power Breakdowns  

E-Print Network [OSTI]

learning. Keywords Crisis management, user-centered design, inter-organizational communication and learningWiedenhöfer et al. Inter-Organizational Crisis Management Infrastructure for Electrical Power Breakdowns Inter-Organizational Crisis Management Infrastructures for Electrical Power Breakdowns Torben

209

Two-dimensional space-resolved emission spectroscopy of laser ablation plasma in water  

SciTech Connect (OSTI)

We developed a method for two-dimensional space-resolved emission spectroscopy of laser-induced plasma in water to investigate the spatial distribution of atomic species involved in the plasma. Using this method, the laser ablation plasma produced on a Cu target in 5 mM NaCl aqueous solution was examined. The emission spectrum varied considerably depending on the detecting position. The temperature and the atomic density ratio N{sub Na}/N{sub Cu} at various detecting positions were evaluated by fitting emission spectra to a theoretical model based on the Boltzmann distribution. We are successful in observing even a small difference between the distributions of the plasma parameters along the directions vertical and horizontal to the surface. The present approach gives direct information for sound understanding of the behavior of laser ablation plasma produced on a solid surface in water.

Matsumoto, Ayumu; Tamura, Ayaka; Fukami, Kazuhiro; Ogata, Yukio H. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan); Sakka, Tetsuo [Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510 (Japan)

2013-02-07T23:59:59.000Z

210

Optical instrumentation for on-line analysis of chemical processes  

SciTech Connect (OSTI)

Optical diagnostics provide the capability for nonintrusive, on-line, real time analysis of chemical process streams. Several laser-based methods for monitoring fossil energy processes have been evaluated. Among the instrumentation techniques which appear quite promising are coherent anti-Stokes Raman spectroscopy (CARS), laser-induced breakdown spectroscopy (LIBS), and synchronous detection of laser-induced fluorescence (SDLIF). A CARS diagnostic was implemented on a coal gasifier and was successfully employed to measure species concentrations and temperatures within the process stream. The LIBS approach has been used to identify total trace impurities (e.g., Na, K, and S) within a gasifier. Recently, individual components in mixtures of aromatics hydrocarbons have been resolved via the synchronous detection of laser-induced fluorescence. 9 figures.

Hartford, A. Jr.; Cremers, D.A.; Loree, T.R.; Quigley, G.P.

1983-01-01T23:59:59.000Z

211

Measurements of electron avalanche formation time in W-band microwave air breakdown  

SciTech Connect (OSTI)

We present measurements of formation times of electron avalanche ionization discharges induced by a focused 110 GHz millimeter-wave beam in atmospheric air. Discharges take place in a free volume of gas, with no nearby surfaces or objects. When the incident field amplitude is near the breakdown threshold for pulsed conditions, measured formation times are {approx}0.1-2 {mu}s over the pressure range 5-700 Torr. Combined with electric field breakdown threshold measurements, the formation time data shows the agreement of 110 GHz air breakdown with the similarity laws of gas discharges.

Cook, Alan M.; Hummelt, Jason S.; Shapiro, Michael A.; Temkin, Richard J. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, 167 Albany St., Cambridge, Massachusetts 02139 (United States)

2011-08-15T23:59:59.000Z

212

Vacuum breakdown mechanisms, and X-ray pulses in accelerators  

Science Journals Connector (OSTI)

During the conditioning of evacuated accelerator tubes, groups of discrete X-ray signals with apparent energies of greater than 300 keV are observed. A mechanism to explain the X-ray emission is proposed in terms of a series of transient vacuum arc discharges. A review is given of vacuum breakdown mechanisms, and of the most likely processes occurring in accelerator tubes during the conditioning process. In the case of the vacuum accelerator tube, there is initially no gaseous medium, but the applied voltage of 30 kV between the tube electrodes is sufficient to lead to the formation of a vacuum arc if there are fine whiskers, impurities, or accelerated dust particles present. Such a vacuum discharge will have a very short life (?1 ?s), as the current of the arc will cause the collapse of the electrode voltage which is maintained by a small current through 600 M? resistors. During the discharge, electrons will escape into the accelerator tube, and fall through several sections to be finally arrested, producing the discrete X-ray signals. The vacuum arc will release charged molten droplets of anode material into the high-field region; after some delay, these droplets will trigger further arcs in different sections of the tube. The triggered arcs will be at the inner edges of the electrode where the droplets hit the electrode, and where electrons are most readily released into the accelerator tube. Thus a whole series of high energy X-ray signals are observed.

R Morrow; D.C Weisser

1996-01-01T23:59:59.000Z

213

Breakdown of large-scale circulation in turbulent rotating convection  

Science Journals Connector (OSTI)

Turbulent rotating convection in a cylinder is investigated both numerically and experimentally at Rayleigh number Ra=109 and Prandtl number ?=6.4. In this letter we discuss two topics: the breakdown under rotation of the domain-filling large-scale circulation (LSC) typical for confined convection, and the convective heat transfer through the fluid layer, expressed by the Nusselt number. The presence of the LSC is addressed for several rotation rates. For Rossby numbers Ro1.2 no LSC is found (the Rossby number indicates relative importance of buoyancy over rotation, hence small Ro indicates strong rotation). For larger Rossby numbers a precession of the LSC in anticyclonic direction (counter to the background rotation) is observed. It is shown that the heat transfer has a maximal value close to Ro=0.18 being about 15% larger than in the non-rotating case Ro=?. Since the LSC is no longer present at this Rossby value we conclude that the peak heat transfer is independent of the LSC.

R. P. J. Kunnen; H. J. H. Clercx; B. J. Geurts

2008-01-01T23:59:59.000Z

214

Structure test results from SLAC (NLCTA) show breakdown and damage at  

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

test results from SLAC (NLCTA) show breakdown and damage at test results from SLAC (NLCTA) show breakdown and damage at gradients well below expectations from single cavity tests. The papers and presentations listed here illustrate some recent work on the topic. SLAC meeting notes are found here. Overview - Basic understanding of the role of particulate contaminants (Hasan Padamsee, PAC97) Literature study - Field emission and high voltage breakdown - (presentation by D. Burke 1996) References listed in D. Burke summary: SLAC Breakdown in S-band structures (Loew and Wang 1988) High Gradient studies in structures (Loew and Wang 1990) High Gradient tests (Wang et.al. 1994) Properties of Periodic Accelerating Structures for Linear Colliders (Wang 1989) Field emission in high gradient structures - (Loew and Wang -School 1997)

215

Elucidating the mechanisms behind pre-breakdown phenomena in transformer oil systems  

E-Print Network [OSTI]

The widespread use of dielectric liquids for high voltage insulation and power apparatus cooling is due to their greater electrical breakdown strength and thermal conductivity than gaseous insulators. In addition, their ...

Hwang, Jae-Won George, 1980-

2010-01-01T23:59:59.000Z

216

ITCZ breakdown in three-dimensional flows Chia-chi Wang and  

E-Print Network [OSTI]

and Miller 1976; Hack et al. 1989). Some of the disturbances may intensify and grow into tropical cy- clones may reform in the same general location. This process is referred to as "ITCZ breakdown" (Hack et al

Magnusdottir, Gudrun

217

Collision and diffusion in microwave breakdown of nitrogen gas in and around microgaps  

SciTech Connect (OSTI)

The microwave induced breakdown of N{sub 2} gas in microgaps was modeled using the collision frequency between electrons and neutral molecules and the effective electric field concept. Low pressure breakdown at the threshold electric field occurs outside the gap, but at high pressures it is found to occur inside the microgap with a large threshold breakdown electric field corresponding to a very large electron oscillation amplitude. Three distinct pressure regimes are apparent in the microgap breakdown: a low pressure multipactor branch, a mid-pressure Paschen branch, both of which occur in the space outside the microgap, and a high pressure diffusion-drift branch, which occurs inside the microgap. The Paschen and diffusion-drift branches are divided by a sharp transition and each separately fits the collision frequency model. There is evidence that considerable electron loss to the microgap faces accompanies the diffusion-drift branch in microgaps.

Campbell, J. D.; Lenters, G. T. [Grand Valley State University, Allendale, MI 49401 (United States)] [Grand Valley State University, Allendale, MI 49401 (United States); Bowman, A.; Remillard, S. K., E-mail: remillard@hope.edu [Hope College, Holland, MI 49423 (United States)

2014-01-15T23:59:59.000Z

218

The Free Energy of Glycogen-Lactic Acid Breakdown in Muscle  

Science Journals Connector (OSTI)

1 January 1929 research-article The Free Energy of Glycogen-Lactic Acid Breakdown in Muscle Dean Burk The Royal Society is collaborating with JSTOR to digitize, preserve...

1929-01-01T23:59:59.000Z

219

E-Print Network 3.0 - atria phosphatidylinositol breakdown Sample...  

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

breakdown Page: << < 1 2 3 4 5 > >> 1 ISSN: 1524-4539 Copyright 2010 American Heart Association. All rights reserved. Print ISSN: 0009-7322. Online Summary: ,25 presented...

220

Visualization of Intricate Flow Structures for Vortex Breakdown Analysis Xavier Tricoche  

E-Print Network [OSTI]

Hansen University of Utah Figure 1: Vortex breakdown bubble in numerical simulation of a cylindrical to study their impact on flight stability. Yet, to fully exploit the huge amount of information contained

Utah, University of

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


221

Substitutional Routing for Trunk Line Break-Down in the Teletransmission Network  

Science Journals Connector (OSTI)

Trunk-line break-down in teletransmission network interrupts some number of the routes of some different links. It makes necessary to restore, at least partially, failed transmission possibilities for each affect...

dr ing. Kornel Wydro

1988-01-01T23:59:59.000Z

222

Studies of electrical breakdown processes across vacuum gaps between metallic electrodes  

Science Journals Connector (OSTI)

Abstract An experimental program to elucidate the physical causes of electrical breakdown across vacuum gaps, such as those that occur in charged particle accelerators, is discussed. Magnetic insulation is explored as a technique to differentiate between field emission of electrons and clump acceleration as possible causative mechanisms for the onset of breakdown. The results and limitations of an exploratory experiment are described, along with plans for a more comprehensive experimental and theoretical campaign.

L.R. Grisham; A. Von Halle; A.F. Carpe; Guy Rossi; K.R. Gilton; E.D. McBride; E.P. Gilson; A. Stepanov; T.N. Stevenson

2014-01-01T23:59:59.000Z

223

Factors contributing to the breakdown of sodium beta-alumina  

SciTech Connect (OSTI)

Clarification of the breakdown process occurring during charge transfer in sodium beta alumina solid electrolytes was derived from: (1) studying the effects of molten sodium contact at 350/sup 0/C on single crystal sodium beta alumina and polycrystalline sodium beta alumina; (2) determination of critical current density by monitoring acoustic emissions accompanying crack growth in sodium/sodium beta alumina/sodium cells subjected to linear current ramping at 1 mA cm/sup -2/ sec/sup -1/; (3) failure analysis conducted on cycled electrolytes, some from commercial sodium/sulfur cells, which had been subjected to up to 703 Ahr cm/sup -2/ of charge transfer. Gray coloration developing in beta aluminas in contact with molten sodium was found to be a consequence of formation, through reduction by sodium, of oxygen vacancies charge compensated by electrons. Electronic conductivity of the electrolyte increases as a result. No second phase formation was detected. Colored electrolytes from sodium/sulfur cells show evidence of a newly recognized degradation mechanism in which fracture occurs when sodium is reduced and deposited internally under pressure as metal in regions where an electronic conductivity gradient exists. Heating colored beta aluminas in air produces reoxidation and bleaching. Kinetics and other properties of the coloration and bleaching processes were determined. Critical current density was found to bear an inverse relation to average electrolyte grain size. Evidence was found in the cycled electrolytes for a slow crack growth mechanism and a progressive mode of degradation advancing from the sulfur electrode interface. Implications of the findings for the construction and operation of sodium/sulfur battery systems are discussed.

Buechele, A.C.

1982-05-01T23:59:59.000Z

224

Application of laser ignition on laminar flame front investigation  

Science Journals Connector (OSTI)

The first stages of laser-induced spark ignition were investigated as a function of time....4/air burner. Laser-induced breakdown was achieved by focusing a ... nanosecond pulse from a Q-switched Nd:YAG laser. An...

J.-L. Beduneau; Y. Ikeda

2004-01-01T23:59:59.000Z

225

Comparison of femtosecond and nanosecond laser-induced damage in HfO{sub 2} single-layer film and HfO{sub 2}-SiO{sub 2} high reflector  

SciTech Connect (OSTI)

HfO{sub 2} single layers, 800 nm high-reflective (HR) coating, and 1064 nm HR coating were prepared by electron-beam evaporation. The laser-induced damage thresholds (LIDTs) and damage morphologies of these samples were investigated with single-pulse femtosecond and nanosecond lasers. It is found that the LIDT of the HfO{sub 2} single layer is higher than the HfO{sub 2}-SiO{sub 2} HR coating in the femtosecond regime, while the situation is opposite in the nanosecond regime. Different damage mechanisms are applied to study this phenomenon. Damage morphologies of all samples due to different laser irradiations are displayed.

Yuan Lei; Zhao Yuanan; Shang Guangqiang; Wang Chengren; He Hongbo; Shao Jianda; Fan Zhengxiu [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China) and Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China) and Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

2007-03-15T23:59:59.000Z

226

Nuclear envelope breakdown induced by herpes simplex virus type 1 involves the activity of viral fusion proteins  

Science Journals Connector (OSTI)

Abstract Herpesvirus infection reorganizes components of the nuclear lamina usually without loss of integrity of the nuclear membranes. We report that wild-type HSV infection can cause dissolution of the nuclear envelope in transformed mouse embryonic fibroblasts that do not express torsinA. Nuclear envelope breakdown is accompanied by an eight-fold inhibition of virus replication. Breakdown of the membrane is much more limited during infection with viruses that lack the gB and gH genes, suggesting that breakdown involves factors that promote fusion at the nuclear membrane. Nuclear envelope breakdown is also inhibited during infection with virus that does not express UL34, but is enhanced when the US3 gene is deleted, suggesting that envelope breakdown may be enhanced by nuclear lamina disruption. Nuclear envelope breakdown cannot compensate for deletion of the UL34 gene suggesting that mixing of nuclear and cytoplasmic contents is insufficient to bypass loss of the normal nuclear egress pathway.

Martina Maric; Alison C. Haugo; William Dauer; David Johnson; Richard J. Roller

2014-01-01T23:59:59.000Z

227

The influence of tropical operating conditions on the AC and impulse breakdown strength in gas insulated substation (GIS):.  

E-Print Network [OSTI]

??The ambient conditions could influence the breakdown strength of gas insulated substation. It is important to check if this influence will put the GIS into (more)

Sihombing, H.

2009-01-01T23:59:59.000Z

228

Pressure, temperature, and dissolved gas dependence of dielectric breakdown in water.  

Science Journals Connector (OSTI)

It has been shown experimentally that the optical breakdown strength of water is a pressure dependent quantity growing with increasing pressure. The dependence of the breakdown strength on temperature and dissolved gas concentration over a larger range of pressures will be observed. Using a custom fabricated pressure vessel and high?power Nd:YAG laser breakdown events will be generated and observed over a range of pressures from 0 to 25 kpsi. Observations of breakdown events will be made using a high?speed photodetector located behind the pressure vessels optical windows. Dissolved gas concentration will be controlled and varied using a custom water preparation system over a range from waters vapor pressure (?20 torr) to atmospheric pressure.Temperature will be monitored using a thermocouple attached to the pressure vessel and the temperature dependence will be measured over a range from 20 to 35 C. A comparison between current single detector methods and previous imaging methods of using breakdown to determine absolute pressure will then be made. [Work supported by Impulse Devices Inc.

Jonathan Sukovich; R. Glynn Holt

2010-01-01T23:59:59.000Z

229

X-Band Photonic Band-Gap Accelerator Structure Breakdown Experiment  

SciTech Connect (OSTI)

In order to understand the performance of photonic band-gap (PBG) structures under realistic high gradient, high power, high repetition rate operation, a PBG accelerator structure was designed and tested at X band (11.424 GHz). The structure consisted of a single test cell with matching cells before and after the structure. The design followed principles previously established in testing a series of conventional pillbox structures. The PBG structure was tested at an accelerating gradient of 65 MV/m yielding a breakdown rate of two breakdowns per hour at 60 Hz. An accelerating gradient above 110 MV/m was demonstrated at a higher breakdown rate. Significant pulsed heating occurred on the surface of the inner rods of the PBG structure, with a temperature rise of 85 K estimated when operating in 100 ns pulses at a gradient of 100 MV/m and a surface magnetic field of 890 kA/m. A temperature rise of up to 250 K was estimated for some shots. The iris surfaces, the location of peak electric field, surprisingly had no damage, but the inner rods, the location of the peak magnetic fields and a large temperature rise, had significant damage. Breakdown in accelerator structures is generally understood in terms of electric field effects. These PBG structure results highlight the unexpected role of magnetic fields in breakdown. The hypothesis is presented that the moderate level electric field on the inner rods, about 14 MV/m, is enhanced at small tips and projections caused by pulsed heating, leading to breakdown. Future PBG structures should be built to minimize pulsed surface heating and temperature rise.

Marsh, Roark A.; /MIT /MIT /NIFS, Gifu /JAERI, Kyoto /LLNL, Livermore; Shapiro, Michael A.; Temkin, Richard J.; /MIT; Dolgashev, Valery A.; Laurent, Lisa L.; Lewandowski, James R.; Yeremian, A.Dian; Tantawi, Sami G.; /SLAC

2012-06-11T23:59:59.000Z

230

The effects of a jet on vortex breakdown over a sharp leading-edge delta wing  

E-Print Network [OSTI]

THE EFFECTS OF A JET ON VORTEX BREAKDOWN OVER A SHARP LEADING-EDGE DELTA WING A Thesis Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1985... Major Subject: Aerospace Engineering THE EFFECTS OF A JET ON VORTEX BREAKDOWN OVER A SHARP LEADING-EDGE DELTA WING A Thesis by IAN KENNETH MAYNARD Approved as to style and content by: Cyrus Ostowar (Chairman of Committee) Stan J Miley (M er...

Maynard, Ian Kenneth

2012-06-07T23:59:59.000Z

231

In-situ characterization of femtosecond laser-induced crystallization in borosilicate glass using time-resolved surface third-harmonic generation  

SciTech Connect (OSTI)

Coherent phonon dynamics in condensed-phase medium are responsible for important material properties including thermal and electrical conductivities. We report a structural dynamics technique, time-resolved surface third-harmonic generation (TRSTHG) spectroscopy, to capture transient phonon propagation near the surface of polycrystalline CaF{sub 2} and amorphous borosilicate (BK7) glass. Our approach time-resolves the background-free, high-sensitivity third harmonic generation (THG) signal in between the two crossing near-IR pulses. Pronounced intensity quantum beats reveal the impulsively excited low-frequency Raman mode evolution on the femtosecond to picosecond timescale. After amplified laser irradiation, danburite-crystal-like structure units form at the glass surface. This versatile TRSTHG setup paves the way to mechanistically study and design advanced thermoelectrics and photovoltaics.

Liu, Weimin; Wang, Liang; Han, Fangyuan; Fang, Chong [Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States)] [Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States)

2013-11-11T23:59:59.000Z

232

Biochemical evidence that starch breakdown by Bacteroides thetaiotaomicron involves outer membrane starch-binding sites and periplasmic starch-degrading enzymes.  

Science Journals Connector (OSTI)

...can utilize amylose, amylopectin, and pullulan...cell-associated amylase, amylopectinase...breakdown, alpha-glucosidase...can utilize amylose, amylopectin, and pullulan...cell-associated amylase, amylopectinase...breakdown, alpha-glucosidase...

K L Anderson; A A Salyers

1989-06-01T23:59:59.000Z

233

Biochemical evidence that starch breakdown by Bacteroides thetaiotaomicron involves outer membrane starch-binding sites and periplasmic starch-degrading enzymes.  

Science Journals Connector (OSTI)

...cell-associated amylase, amylopectinase...associated with starch breakdown, alpha-glucosidase...cell-associated amylase, amylopectinase...associated with starch breakdown, alpha-glucosidase...inducer of the starch- degrading...inducers or that break- down of maltose...

K L Anderson; A A Salyers

1989-06-01T23:59:59.000Z

234

Microsoft PowerPoint - Proceedings Cover Sheets  

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

Total Soil Carbon and Other Nutrients Using Laser-Induced Breakdown Total Soil Carbon and Other Nutrients Using Laser-Induced Breakdown Spectroscopy (LIBS) R. D. Harris, P. J. Unkefer, M. H. Ebinger, C. W. Meyer, J. E. Fessenden-Rahn, and S. M. Clegg Introduction Developing accurate and rapid methods of measuring soil and plant nutrients is important for increasing soil productivity as well as reducing the costs of precision farming. Loss of soil carbon during the past 150 years has depleted many of the most productive soils and resulted in degradation of marginal soils. Organic matter is needed in soil to provide texture and prevent leaching of other essential nutrients. Terrestrial carbon management and sequestration produces a variety of benefits which include reclamation of degraded lands, increased soil productivity, reduced erosion, and potentially, slowing carbon

235

EXPERIMENTAL STUDIES OF RF BREAKDOWNS IN THE COUPLER OF THE TTF RF GUN  

E-Print Network [OSTI]

EXPERIMENTAL STUDIES OF RF BREAKDOWNS IN THE COUPLER OF THE TTF RF GUN J.-P. Carneiro , S I, the RF gun of the TESLA Test Facility (TTF) has been operated with long RF pulses (up to 0.9 ms Fermilab has developed and delivered to DESY two RF guns for the operation of phase 1 of the TESLA Test

236

Empirical Features of Spontaneous and Induced Traffic Breakdowns in Free Flow at Highway Bottlenecks  

E-Print Network [OSTI]

Based on an empirical study of real field traffic data measured in 1996--2014 through road detectors installed on German freeways, we reveal physical features of empirical nuclei for spontaneous traffic breakdown in free flow at highway bottlenecks. It is shown that the source of a nucleus for traffic breakdown is the solely difference between empirical spontaneous and induced traffic breakdowns at a highway bottleneck. Microscopic traffic simulations with a stochastic traffic flow model in the framework of three-phase theory explain the empirical findings. It turns out that in the most cases, a nucleus for empirical spontaneous traffic breakdown occurs through an interaction of one of waves in free flow with an empirical permanent speed disturbance localized at a highway bottleneck. The wave is a localized structure in free flow, in which the total flow rate is larger and the speed averaged across the highway is smaller than outside the wave. The waves in free flow appear due to oscilations in the percentage...

Kerner, Boris S; Klenov, Sergey L; Rehborn, Hubert; Leibel, Michael

2015-01-01T23:59:59.000Z

237

The onset of optical breakdown in KrF-laser-irradiated silica glass surfaces  

E-Print Network [OSTI]

A synthetic fused silica obtained from Tosoh SGM Co., ESL-1000 (OH % 1200 wt. ppm), with a thick- ness of 2 mmThe onset of optical breakdown in KrF-laser-irradiated silica glass surfaces Y. Kawaguchia,* , A Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1

Dickinson, J. Thomas

238

Breakdown of 2mm symmetry in electron diffraction from multiwalled carbon nanotubes  

E-Print Network [OSTI]

Breakdown of 2mm symmetry in electron diffraction from multiwalled carbon nanotubes Zejian Liu of single-walled carbon nanotubes always have 2mm symmetry regardless if the nanotubes them- selves have such symmetry. We here show that, for the case of multiwalled carbon nanotubes, the 2mm symmetry can break down

Qin, Lu-Chang

239

Formation and direct writing of color centers in LiF using a laser-induced extreme ultraviolet plasma in combination with a Schwarzschild objective  

SciTech Connect (OSTI)

In order to generate high-energy densities of 13.5 nm radiation, an extreme ultraviolet (EUV) Schwarzschild mirror objective with a numerical aperture of 0.44 and a demagnification of 10 was developed and adapted to a compact laser-based EUV source. The annular spherical mirror substrates were coated with Mo/Si multilayer systems. With a single mirror reflectance of more than 65% the total transmittance of the Schwarzschild objective exceeds 40% at 13.5 nm. From the properties of the EUV source (pulse energy 3 mJ at 13.5 nm and plasma diameter approximately 300 {mu}m), energy densities of 73 mJ/cm{sup 2} at a pulse length of 6 ns can be estimated in the image plane of the objective. As a first application, the formation of color centers in lithium fluoride crystals by EUV radiation was investigated. F{sub 2}, F{sub 3}, and F{sub 3}{sup +} color centers could be identified by absorption spectroscopy. The formation dynamics was studied as a function of the EUV dose. By imaging of a pinhole positioned behind the plasma, an EUV spot of 5 {mu}m diameter was generated, which accomplishes direct writing of color centers with micrometer resolution.

Barkusky, Frank; Peth, Christian; Mann, Klaus; Feigl, Torsten; Kaiser, Norbert [Laser-Laboratorium Goettingen e.V., Hans-Adolf-Krebs-Weg 1, D-37077 Goettingen (Germany); Fraunhofer-Institut fuer Angewandte Optik und Feinmechanik, Albert-Einstein-Strasse 7, D-07745 Jena (Germany)

2005-10-15T23:59:59.000Z

240

Formation and direct writing of color centers in LiF using a laser-induced extreme ultraviolet plasma in combination with a Schwarzschild objective  

Science Journals Connector (OSTI)

In order to generate high-energy densities of 13.5 nm radiation an extreme ultraviolet(EUV) Schwarzschild mirror objective with a numerical aperture of 0.44 and a demagnification of 10 was developed and adapted to a compact laser-based EUVsource. The annular spherical mirror substrates were coated with Mo ? Si multilayer systems. With a single mirror reflectance of more than 65% the total transmittance of the Schwarzschild objective exceeds 40% at 13.5 nm . From the properties of the EUVsource (pulse energy 3 mJ at 13.5 nm and plasma diameter approximately 300 ? m ) energy densities of 73 mJ ? cm 2 at a pulse length of 6 ns can be estimated in the image plane of the objective. As a first application the formation of color centers in lithium fluoride crystals by EUVradiation was investigated. F 2 F 3 and F 3 + color centers could be identified by absorption spectroscopy. The formation dynamics was studied as a function of the EUV dose. By imaging of a pinhole positioned behind the plasma an EUV spot of 5 ? m diameter was generated which accomplishes direct writing of color centers with micrometer resolution.

Frank Barkusky; Christian Peth; Klaus Mann; Torsten Feigl; Norbert Kaiser

2005-01-01T23:59:59.000Z

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


241

EMSL - Spectroscopy and Diffraction  

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

loss spectroscopy and electron backscatter diffraction Local Electrode Atom Probe tomography system with 355 nm UV laser and reflectron flight path for high mass resolution...

242

A Theory for the Comparative RF Surface Fields at Destructive Breakdown for Various Metels  

SciTech Connect (OSTI)

By destructive breakdown we mean a breakdown event that results in surface melting over large areas on the iris tip region of an accelerator structure. The melting is the result of the formation of macroscopic areas of plasma in contact with the surface. The plasma bombards the surface with an intense ion current ({approx}10{sup 8} A/cm{sup 2}), which is equivalent to a pressure on the order of a thousand Atmospheres. A radial gradient in the pressure produces a ponderomotive force that causes molten copper to migrate away from the iris tip, resulting in a measurable change in the iris shape. This distortion in the iris shape in turn produces an error in the cell-to-cell phase shift of the accelerating wave with a consequent loss in synchronism with the electron beam and a reduction in the effective accelerating gradient. Assuming a long lifetime is desired for the structure, such breakdowns must be avoided or at least limited in number. The accelerating gradient at which these breakdowns begin to occur imposes, therefore, an absolute limit on an operationally attainable gradient. The destructive breakdown limit (DBL) on the accelerating gradient depends on a number of factors, such as the geometry of the irises and coupler, the accuracy of the cell-to-cell tuning (''field flatness''), and the properties of the metal used in the high E-field regions of the structure. In this note we consider only the question of the dependence of the DBL on the metal used in the high surface field areas of the structure. There are also various types of non-destructive breakdowns (NDB's) that occur during the ''processing'' period that, after the initial application of high power, is necessary to bring the gradient up to the desired operating level. During this period, as the input power and gradient are gradually increased, thousands of such NDB's occur. These breakdowns produce a collapse in the fields in the structure as energy stored in the fields is absorbed at the breakdown site. They are often marked by vacuum bursts and an increase in power reflected from the structure. The usual cause for NDB's during processing is the ''explosion'' of field emitters at sharp geometrical features on the metal surface. Exposed impurities in the metal surface can also produce NDB's as they are ''burned'' off by H-field heating or explosive field emission. The breakdown process can be roughly divided into four stages: (1) the formation of ''plasma spots'' at field emission sites, each spot leaving a crater-like footprint; (2) crater clustering, and the formation of areas with hundreds of overlapping craters; (3) surface melting in the region of a crater cluster; (4) the process after surface melting that leads to destructive breakdown.

Wilson, Perry; /SLAC

2006-03-20T23:59:59.000Z

243

Accurate Analytic Potential and Born-Oppenheimer Breakdown Functions for MgH and MgD from a Direct-Potential-Fit Data Analysis  

E-Print Network [OSTI]

Accurate Analytic Potential and Born-Oppenheimer Breakdown Functions for MgH and MgD from a Direct-potential-fit analysis to yield improved analytic potential energy and Born-Oppenheimer breakdown functions allowed us also to determine the adiabatic Born- Oppenheimer breakdown effects in this molecule

Le Roy, Robert J.

244

YAG laser-induced structural modification in transition metal ion containing 40K{sub 2}O-40Nb{sub 2}O{sub 5}-20SiO{sub 2} glasses  

SciTech Connect (OSTI)

Glasses with the compositions of 40K{sub 2}O-40Nb{sub 2}O{sub 5}-20SiO{sub 2} (in mol%) containing different concentrations (0.01, 1 and 2 mol%) of NiO were prepared by a melt quenching technique. The glasses were irradiated with a continuous wave Nd:YAG laser with a wavelength of 1064 nm, and a metastable crystalline phase of KNbO{sub 3} was obtained. In 2 mol% NiO-doped glass, lines with a width of {approx}10 {mu}m are successfully patterned by laser irradiations with a power of 0.9 W and a scanning speed of 15 {mu}m/s. It is found from micro-Raman scattering spectra that the lines are composed of the metastable crystalline phase of KNbO{sub 3}. The crystallization mechanism in Nd:YAG laser-induced crystallization in the glasses is discussed in comparison with the usual crystallization in an electric furnace.

Venkataraman, B. Harihara [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan); Komatsu, Takayuki [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan)], E-mail: komatsu@mst.nagaokaut.ac.jp

2008-10-02T23:59:59.000Z

245

Effect of Bubbles on Liquid Nitrogen Breakdown in Plane-Plane Electrode Geometry From 100-250 kPa  

SciTech Connect (OSTI)

Liquid nitrogen (LN(2)) is used as the cryogen and dielectric for many high temperature superconducting, high voltage applications. When a quench in the superconductor occurs, bubbles are generated which can affect the dielectric breakdown properties of the LN(2). Experiments were performed using plane-plane electrode geometry where bubbles were introduced into the gap through a pinhole in the ground electrode. Bubbles were generated using one or more kapton heaters producing heater powers up to 30 W. Pressure was varied from 100-250 kPa. Breakdown strength was found to be relatively constant up to a given heater power and pressure at which the breakdown strength drops to a low value depending on the pressure. After the drop the breakdown strength continues to drop gradually at higher heater power. This is particularly illustrated at 100 kPa. After the drop in breakdown strength the breakdown is believed to be due to the formation of a vapor bridge. Also the heater power at which the breakdown strength changes from that of LN(2) to that of gaseous nitrogen increases with increasing pressure. The data can provide design constraints for high temperature superconducting fault current limiters (FCLs) so that the formation of a vapor bridge can be suppressed or avoided.

Sauers, Isidor [ORNL; James, David Randy [ORNL; Tuncer, Enis [ORNL; Polyzos, Georgios [ORNL; Pace, Marshall O [ORNL

2011-01-01T23:59:59.000Z

246

A Theory for the RF Surface Field for Various Metals at the Destructive Breakdown Limit  

SciTech Connect (OSTI)

By destructive breakdown we mean a breakdown event that results in surface melting over a macroscopic area in a high E-field region of an accelerator structure. A plasma forms over the molten area, bombarding the surface with an intense ion current ({approx} 10{sup 8} A/cm{sup 2}), equivalent to a pressure of about a thousand Atmospheres. This pressure in turn causes molten copper to migrate away from the iris tip, resulting in measurable changes in the iris shape. The breakdown process can be roughly divided into four stages: (1) the formation of ''plasma spots'' at field emission sites, each spot leaving a crater-like footprint; (2) crater clustering, and the formation of areas with hundreds of overlapping craters; (3) surface melting in the region of a crater cluster; (4) the process after surface melting that leads to destructive breakdown. The physics underlying each of these stages is developed, and a comparison is made between the theory and experimental evidence whenever possible. The key to preventing breakdown lies in stage (3). A single plasma spot emits a current of several amperes, a portion of which returns to impact the surrounding area with a power density on the order 10{sup 7} Watt/cm{sup 2}. This power density is not quite adequate to melt the surrounding surface on a time scale short compared to the rf pulse length. In a crater field, however, the impact areas from multiple plasma spots overlap to provide sufficient power density for surface melting over an area on the order of 0.1 mm{sup 2} or more. The key to preventing breakdown is to choose an iris tip material that requires the highest power density (proportional to the square of the rf surface field) for surface melting, taking into account the penetration depth of the impacting electrons. The rf surface field required for surface melting (relative to copper) has been calculated for a large number elementary metals, plus stainless-steel and carbon.

Wilson, Perry B.; /SLAC

2007-03-06T23:59:59.000Z

247

Evidence of Magnetic Breakdown on the Defects With Thermally Suppressed Critical Field in High Gradient SRF Cavities  

SciTech Connect (OSTI)

At SRF 2011 we presented the study of quenches in high gradient SRF cavities with dual mode excitation technique. The data differed from measurements done in 80's that indicated thermal breakdown nature of quenches in SRF cavities. In this contribution we present analysis of the data that indicates that our recent data for high gradient quenches is consistent with the magnetic breakdown on the defects with thermally suppressed critical field. From the parametric fits derived within the model we estimate the critical breakdown fields.

Eremeev, Grigory [JLAB; Palczewski, Ari [JLAB

2013-09-01T23:59:59.000Z

248

Microsoft Word - SEC J_Appendix F - National Work Breakdown Str_Negotiated  

National Nuclear Security Administration (NNSA)

F, Page 1 F, Page 1 SECTION J APPENDIX F NATIONAL WORK BREAKDOWN STRUCTURE The Department of Energy, National Nuclear Security Administration (DOE/NNSA), Office of Defense Programs, manages a large, complex, and diverse portfolio of weapons activities. To help facilitate and integrate the management of this portfolio, the Office of Defense Programs is establishing a National Work Breakdown Structure (NWBS). The NWBS will provide a consistent framework for planning, programming, budgeting, and evaluation of work required to execute the Defense Programs mission. Over time, the NWBS is anticipated to be expanded to all NNSA and DOE program activities. The NWBS will be contained in a relational database that serves as an easy-to-use tool for DOE/NNSA

249

Non-Gaussian Resistance Noise near Electrical Breakdown in Granular Materials  

E-Print Network [OSTI]

The distribution of resistance fluctuations of conducting thin films with granular structure near electrical breakdown is studied by numerical simulations. The film is modeled as a resistor network in a steady state determined by the competition between two biased processes, breaking and recovery. Systems of different sizes and with different levels of internal disorder are considered. Sharp deviations from a Gaussian distribution are found near breakdown and the effect increases with the degree of internal disorder. However, we show that in general this non-Gaussianity is related to the finite size of the system and vanishes in the large size limit. Nevertheless, near the critical point of the conductor-insulator transition, deviations from Gaussianity persist when the size is increased and the distribution of resistance fluctuations is well fitted by the universal Bramwell-Holdsworth-Pinton distribution.

C. Pennetta; E. Alfinito; L. Reggiani; S. Ruffo

2004-01-20T23:59:59.000Z

250

Millimeter wave scattering and diffraction in 110 GHz air breakdown plasma  

SciTech Connect (OSTI)

We present measurements of the scattering, reflection, absorption, and transmission of a 1.5 MW, 110 GHz quasioptical gyrotron beam by a self-induced air breakdown plasma. The breakdown forms a periodic array of plasma filaments, oriented parallel to the incident electric field polarization that propagates toward the microwave source. For incident intensity of 3 MW/cm{sup 2}, calorimetric measurements show that as much as 45% of the full beam power is absorbed by the plasma, averaged over the pulse, 1% is reflected backward, and the remainder is transmitted and also scattered into a wide angular spread. We observe that approximately 10 times more power is scattered in the direction perpendicular to the filaments than parallel. The far-field angular distribution of transmitted power exhibits a diffraction pattern that changes throughout the 2-{mu}s life of the plasma.

Cook, Alan M.; Hummelt, Jason S.; Shapiro, Michael A.; Temkin, Richard J. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2013-04-15T23:59:59.000Z

251

An approach to predict tarmat breakdown in Minagish Reservoir in Kuwait  

SciTech Connect (OSTI)

Minagish Oolite reservoir, Minagish Field in Kuwait is characterized by tarmat presence at the oil-water contact. A water flooding project is planned for the reservoir. This paper discusses the possibility of tarmat break-down upon water injection below it. It was found that differential pressure at tarmat would be mainly due to water injection and that differential pressure due to oil production would be negligible. This paper suggests a technique to predict tarmat break-down time, response time at the nearest producer or observation well and the time at which water injection should be switched from below tarmat to above it. Also, the technique could be used to predict the differential pressure at tarmat anywhere in the reservoir.

Osman, M.E.

1983-03-01T23:59:59.000Z

252

Investigation Of Breakdown Induced Surface Damage On 805 Mhz Pillbox Cavity Interior Surfaces  

E-Print Network [OSTI]

The MuCool Test Area (MTA) at Fermilab is a facility to develop the technology required for ionization cooling for a future Muon Collider and/or Neutrino Factory. As part of this research program, we have tested two 805 MHz vacuum RF cavities in a multi-Tesla magnetic field to study the effects of the static magnetic field on the cavity operation. This study gives useful information on field emitters in the cavity, dark current, surface conditioning, breakdown mechanisms and material properties of the cavity. All these factors determine the maximum accelerating gradient in the cavity. This paper discusses the image processing technique for quantitative estimation of spark damage spot distribution on cavity interior surfaces. The distribution is compared with the electric field distribution predicted by a computer code calculation. The local spark density is proportional to probability of surface breakdown and shows a power law dependence on the maximum electric field (E). This E dependence is consistent with ...

Jana, M R; Leonova, M; Moretti, A; Tollestrup, A; Yonehara, K; Freemire, B; Torun, Y; Bowring, D; Flanagan, G

2014-01-01T23:59:59.000Z

253

* Corresponding author. E-mail address: cparigge@utsi.edu (C. Parigger)  

E-Print Network [OSTI]

Institute, Tullahoma, TN 37388-9700, USA Abstract Laser-induced breakdown and ignition of atmospheric Science Ltd. All rights reserved. 1. Introduction Laser-induced ignition of gas- and two-phase mixtures o as compared to the electric spark. Finally, using #ame detection sensors, a laser-induced ignition source has

Davis, Lloyd M.

254

Geochemistry of Chemical Weapon Breakdown Products on the Seafloor: 1,4-Thioxane in Seawater  

Science Journals Connector (OSTI)

Geochemistry of Chemical Weapon Breakdown Products on the Seafloor: 1,4-Thioxane in Seawater ... The Chemical Weapons Convention mandates the active destruction of chemical weapon (CW) stockpiles held by nations on land, but does not address the far larger quantities of abandoned CW that await passive environmental decomposition following disposal on the sea floor. ... The comingling of disposed weapons material with anoxic hydrate bearing sediments is not theoretical. ...

Xin Zhang; Keith C. Hester; Oscar Mancillas; Edward T. Peltzer; Peter M. Walz; Peter G. Brewer

2009-01-02T23:59:59.000Z

255

Nuclear Raman spectroscopy  

Science Journals Connector (OSTI)

An experiment is described in which the nuclear analog to Raman spectroscopy has been applied to 57Fe. The results of the experiment are given, and future applications of...

DePaola, B D; Wagal, S S; Collins, C B

1985-01-01T23:59:59.000Z

256

Electronic Spectroscopy & Dynamics  

SciTech Connect (OSTI)

The Gordon Research Conference (GRC) on Electronic Spectroscopy and Dynamics was held at Colby College, Waterville, NH from 07/19/2009 thru 07/24/2009. The Conference was well-attended with participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. The GRC on Electronic Spectroscopy & Dynamics showcases some of the most recent experimental and theoretical developments in electronic spectroscopy that probes the structure and dynamics of isolated molecules, molecules embedded in clusters and condensed phases, and bulk materials. Electronic spectroscopy is an important tool in many fields of research, and this GRC brings together experts having diverse backgrounds in physics, chemistry, biophysics, and materials science, making the meeting an excellent opportunity for the interdisciplinary exchange of ideas and techniques. Topics covered in this GRC include high-resolution spectroscopy, biological molecules in the gas phase, electronic structure theory for excited states, multi-chromophore and single-molecule spectroscopies, and excited state dynamics in chemical and biological systems.

Mark Maroncelli, Nancy Ryan Gray

2010-06-08T23:59:59.000Z

257

EMSL: Capabilities: Spectroscopy and Diffraction  

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

Spectroscopy and Diffraction Spectroscopy and Diffraction Additional Information Meet the Spectroscopy and Diffraction Experts Related EMSL User Projects Spectroscopy and Diffraction Tools are Applied to all Science Themes Tutorial: XPS Tools for Surface Analysis Spectroscopy and Diffraction brochure EMSL's suite of spectroscopy and diffraction instruments allows users to study solid-, liquid-, and gas-phase sample structure and composition with remarkable resolution. Ideal for integrated studies, spectrometers and diffractometers are easily coupled with EMSL's computational and modeling capabilities, allowing users to apply a multifaceted research approach for experimental data interpretation and gain fundamental understanding of scientific problems. At EMSL, spectroscopy and diffraction instruments are

258

Technique Subgroupings Spectroscopy  

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

and NSLS-II beamlines according to DOE Technique Scheme and NSLS-II beamlines according to DOE Technique Scheme Technique Subgroupings Spectroscopy 01 - Low Energy Spectroscopy Infrared Photoemission U12IR, U4IR / MET* U5UA, U13 / ESM 02 - Soft X-Ray Spectroscopy Soft X-ray Spectroscopy Tender XAS U4B, U7A, X24A / SST, SSS* X15B, X19A / TES* 03 - Hard X-ray Spectroscopy EXAFS X3A, X3B, X11A, X11B, X18A, X18B, X23A2 / ISS, BMM, QAS*, XAS* 04 - Optics/Calibration/Metrology U3C,X8A/ OFT,MID Scattering 05 X-ray Diffraction X-Ray Powder Diffraction Extreme Conditions Energy Dispersive Micro-Beam Diffraction X7B,X10B,X14A,X16C,X17A / XPD,IXD* X17B2,X17B3,X17C / XPD, TEC*, 4DE* X17B1, X17B2 / NA X13B / MXD* 06 MX, footprinting Protein Crystallography X-ray footprinting X4A, X4C, X6A, X12B, X12C, X25, X29 / FMX, AMX, NYX;

259

Optical Spectroscopy of Tungsten Carbide for Uncertainty Analysis in Electron Electric Dipole Moment Search  

E-Print Network [OSTI]

We perform laser induced fluorescence(LIF) spectroscopy on a pulsed supersonic beam of tungsten carbide(WC) molecules, which has been proposed as a candidate molecular system for a permanent Electric Dipole Moment(EDM) search of the electron in its rovibrational ground state of the X3Delta1 state. In particular, [20.6]Omega=2, v'=4 <- X3Delta1,v"=0 transition at 485nm was used for the detection. The hyperfine structure and the Omega-doublet of the transition are measured, which are essential for estimating the size of the potential systematic uncertainties for electron EDM measurement. For further suppression of the systematic uncertainty, an alternative electron EDM measurement scheme utilizing the g factor crossing point of the Omega-doublet levels is discussed. On the other hand, flux and internal temperature of the molecular beam are characterized, which sets the limit on the statistical uncertainty of the electron EDM experiment. With the given results, the prospect of electron EDM experiment with the...

Lee, J; Skripnikov, L V; Petrov, A N; Titov, A V; Mosyagin, N S; Leanhardt, A E

2012-01-01T23:59:59.000Z

260

Effects of syngas composition on combustion induced vortex breakdown (CIVB) flashback in a swirl stabilized combustor  

Science Journals Connector (OSTI)

Flame flashback attributed to combustion induced vortex breakdown (CIVB) is a major design challenge for swirl stabilized burner combustors. This paper presents an experimental investigation of combustion induced vortex breakdown (CIVB) flashback propensity for flames yielded from Hydrogen (H2)Carbon Monoxide (CO) fuel blends and actual synthesized gas (syngas) mixtures. A two-fold experimental approach, consisting of a high definition digital imaging system and a high speed PIV system, was employed. The main emphasis was on the effect of concentration of different constituents in fuel mixtures on flashback limit. In addition, the effect of Swirl Number on flashback propensity was discussed. The percentage of H2 in fuel mixtures played the dominant role when CIVB flashback occurred. For a given air mass flow rate, the mixture containing a higher percentage of H2 underwent flashback at much leaner conditions. Flashback maps for actual syngas fuel compositions showed a distinct behavior when various concentrations of diluents were introduced in the mixture. For the two major diluents tested, carbon dioxide (CO2) and nitrogen dioxide (NO2), CO2 was more dominant. The effect of Swirl Number on the flashback propensity was also tested and showed a decrease with an increase in Swirl Number. The final portion of this paper also provides an analysis of flow field of reacting flames which revealed complex vortexchemistry interactions leading to vortex breakdown and flashback. Based on the experimental results a parametric model similar to Peclet Number approach was developed employing a flame quenching concept. A value of the quench parameter, Cquench was obtained from the correlation of flow Peclet Number and flame Peclet Number, which was observed to be dominated by the fuel composition rather than Swirl Number.

Bidhan Dam; Gilberto Corona; Mir Hayder; Ahsan Choudhuri

2011-01-01T23:59:59.000Z

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261

Dielectric breakdown properties of hot SF{sub 6}/He mixtures predicted from basic data  

SciTech Connect (OSTI)

Sulfur hexafluoride (SF{sub 6}) gas has a quite high global warming potential and hence it is required that applying any substitute for SF{sub 6} gas. Much interest in the use of a mixture of helium and SF{sub 6} as arc quenching medium was investigated indicating a higher recovery performance of arc interruption than that of pure SF{sub 6}. It is known that the electrical breakdown in a circuit breaker after arc interruption occurs in a hot gas environment, with a complicated species composition because of the occurrence of dissociation and other reactions. The likelihood of breakdown relies on the electron interactions with all these species. The critical reduced electric field strength (the field at which breakdown can occur, relative to the number density) of hot SF{sub 6}/He mixtures related to the dielectric recovery phase of a high voltage circuit breaker is calculated in the temperature range from 300 K to 3500 K. The critically reduced electric field strength of these mixtures was obtained by balancing electron generation and loss mechanisms. These were evaluated using the electron energy distribution function derived from the Boltzmann transport equation under the two-term approximation. Good agreement was found between calculations for pure hot SF{sub 6} and pure hot He and experimental results and previous calculations. The addition of He to SF{sub 6} was found to decrease the critical reduced electric field strength in the whole temperature range due to a lack of electron impact attachment process for helium regardless its high ionization potential. This indicates that not the behaviour of dielectric strength but possibly the higher energy dissipation capability caused mainly by light mass and high specific heat as well as thermal conductivity of atomic helium contributes most to a higher dielectric recovery performance of arc interruption for SF{sub 6}/He mixtures.

Wang, Weizong [Qian Xuesen Laboratory of Space Technology, China Academy of Space Technology, Beijing 100094 (China) [Qian Xuesen Laboratory of Space Technology, China Academy of Space Technology, Beijing 100094 (China); State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an Shaanxi 710049 (China); Tu, Xin; Mei, Danhua [Department of Electrical Engineering and Electronics, The University of Liverpool, Brownlow Hill, Liverpool L69 3GJ (United Kingdom)] [Department of Electrical Engineering and Electronics, The University of Liverpool, Brownlow Hill, Liverpool L69 3GJ (United Kingdom); Rong, Mingzhe [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an Shaanxi 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an Shaanxi 710049 (China)

2013-11-15T23:59:59.000Z

262

Cascade and breakdown in scale-free networks with community structure  

Science Journals Connector (OSTI)

The cascade failures in scale-free networks with community structure are studied and cascade propagation of such networks with different modularity parameters is simulated. It is found that the network with small modularity is much easier to trigger cascade failures than that of the larger one. Furthermore, different removal strategies have some what large effects on the cascade failures aftereffect. The simulations also show that larger modularity and reserve capacity coefficient will delay the breakdown caused by a cascade of network. This is particularly important for such real networks with community as traffic networks, distribution networks, and electrical power grids.

Jian-jun Wu; Zi-you Gao; Hui-jun Sun

2006-12-19T23:59:59.000Z

263

SMB, X-ray Absorption Spectroscopy  

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

Absorption Spectroscopy X-ray Absorption Spectroscopy X-ray absorption spectroscopy (XAS) is a well-established technique for simultaneous local geometric and electronic structure...

264

The planar imaging of laser induced fluorescence of fuel and hydroxyl for a wall-interacting jet in a single-cylinder, automotive-size, optically accessible diesel engine  

Science Journals Connector (OSTI)

Abstract The fuel penetration and reacting diesel jet development have been studied in a small-bore optical engine to better understand a swirl-influenced, wall-interacting diesel flame. The fuel injection was executed for long duration, creating negative ignition dwell conditions in which the start of combustion occurs before the end of injection. Planar laser-induced fluorescence imaging of hydroxyl (OH-PLIF), fuel-PLIF, and line-of-sight integrated chemiluminescence imaging were performed for various combustion stages identified by the in-cylinder pressure traces and apparent heat release rates. These include stages of vaporising fuel penetration, low-temperature reaction, and high-temperature reaction. The fuel-PLIF images show that the fuel penetration is strongly influenced by a swirl flow with the walljet penetration on the up-swirl side being shorter than that on the down-swirl jet. During the low-temperature reaction, cool flame chemiluminescence appears near the walljet head region. Interestingly, this region is where the initial turbulent ring-vortex is formed due to jetwall interactions, suggesting that locally enhanced mixing induced the first-stage ignition. The OH-PLIF images show that the second-stage, high-temperature reaction starts to occur in the same initial head vortex region, which is largely different to the flame base found in the free jet region in heavy-duty, large-bore engines. Since the reaction occurs in the walljet region, the swirl flow impacts the high-temperature reaction significantly, as evidenced by more intense OH signals in the down-swirl jet. This is due to the influence of the swirl flow on the mixing process and the strain rate of the mixture, leading to earlier, faster and stronger high-temperature reaction on the down-swirl side. Upon the end of high temperature reaction, the heat release rate declines and the OH-PLIF signals slowly diminish.

Minh K. Le; Sanghoon Kook; Evatt R. Hawkes

2015-01-01T23:59:59.000Z

265

Theory of Laser-Induced Nuclear Fusion  

Science Journals Connector (OSTI)

It is to the merit of Basov and Krokhin that they discussed135...the possibilities of laser heating of solid deuterium or mixtures of deuterium with tritium for the purpose of nuclear fusion. Not only are the phy...

Heinrich Hora

1975-01-01T23:59:59.000Z

266

IR laser-induced protein crystal transformation  

Science Journals Connector (OSTI)

A novel method and the associated instrumentation for improving crystalline order (higher resolution of X-ray diffraction and reduced mosaicity) of protein crystals by precisely controlled heating is demonstrated. Crystal transformation is optically controlled by a video system.

Kiefersauer, R.

2014-04-26T23:59:59.000Z

267

Laser induced fluorescence measurements of spheromak plasmas.  

E-Print Network [OSTI]

??This thesis reports the results of investigations intended to further the understanding of the formation and evolution of spheromak plasmas via the use of laser (more)

Pracko, Steven Edmund

2007-01-01T23:59:59.000Z

268

Laser-induced "two-atom" coherence  

Science Journals Connector (OSTI)

Our analysis shows that if an electromagnetic field excites a coherent superposition of states of two different types of atoms, then the results of a collision of those two atoms can be quite different from the usual dephasing that a coherently excited atom suffers upon collision with another atom. We present the concept of "two-atom" coherence as one feature of this interaction where the field of a given wavelength may interact with the system coherently over a wide range of internuclear distances.

Munir H. Nayfeh and G. B. Hillard

1984-04-01T23:59:59.000Z

269

Resonant Raman spectroscopy of nanotubes  

Science Journals Connector (OSTI)

...Raman spectroscopy in carbons: from nanotubes to diamond compiled by Andrea C. Ferrari...Robertson Resonant Raman spectroscopy of nanotubes Christian Thomsen 1 Stephanie Reich 2...The experimental situation in carbon nanotubes is reviewed in view of these criteria...

2004-01-01T23:59:59.000Z

270

X-ray absorption spectroscopy  

E-Print Network [OSTI]

009-9473-8 REVIEW X-ray absorption spectroscopy Junko Yano and application of X-ray absorption spectroscopy, bothX-ray absorption near-edge structure (XANES) and extended X-

Yano, Junko; Yachandra, Vittal K.

2009-01-01T23:59:59.000Z

271

X-ray Absorption Spectroscopy  

E-Print Network [OSTI]

type: Review X-ray Absorption Spectroscopy Junko Yano andPhotosystem II; XAS, X-ray absorption spectroscopy; EXAFS,X-ray absorption fine structure; EPR, electron paramagnetic

Yano, Junko

2010-01-01T23:59:59.000Z

272

INVESTIGATION OF BREAKDOWN INDUCED SURFACE DAMAGE ON 805 MHZ PILLBOX CAVITY INTERIOR SURFACES  

SciTech Connect (OSTI)

The MuCool Test Area (MTA) at Fermilab is a facility to develop the technology required for ionization cooling for a future Muon Collider and/or Neutrino Factory. As part of this research program, we have tested two 805 MHz vacuum RF cavities in a multi-Tesla magnetic field to study the effects of the static magnetic field on the cavity operation. This study gives useful information on field emitters in the cavity, dark current, surface conditioning, breakdown mechanisms and material properties of the cavity. All these factors determine the maximum accelerating gradient in the cavity. This paper discusses the image processing technique for quantitative estimation of spark damage spot distribution on cavity interior surfaces. The distribution is compared with the electric field distribution predicted by a computer code calculation. The local spark density is proportional to probability of surface breakdown and shows a power law dependence on the maximum electric field (E). This E dependence is consistent with the dark current calculated from the Fowler-Nordheim equation.

Jana, M.R.; Chung, M.; Leonova, M.; Moretti, A.; Tollestrup,A.; Yonehara, K.; Freemire, B.; Torun, Y.; Bowring, D.; Flanagan, G.

2013-09-25T23:59:59.000Z

273

Effect of high solenoidal magnetic fields on breakdown voltages of high vacuum 805 MHz cavities  

SciTech Connect (OSTI)

There is an on going international collaboration studying the feasibility and cost of building a muon collider or neutrino factory [1,2]. An important aspect of this study is the full understanding of ionization cooling of muons by many orders of magnitude for the collider case. An important muon ionization cooling experiment, MICE [3], has been proposed to demonstrate and validate the technology that could be used for cooling. Ionization cooling is accomplished by passing a high-emittance muon beam alternately through regions of low Z material, such as liquid hydrogen, and very high accelerating RF Cavities within a multi-Tesla solenoidal field. To determine the effect of very large solenoidal magnetic fields on the generation of dark current, x-rays and on the breakdown voltage gradients of vacuum RF cavities, a test facility has been established at Fermilab in Lab G. This facility consists of a 12 MW 805 MHz RF station and a large warm bore 5 T solenoidal superconducting magnet containing a pill box type cavity with thin removable window apertures. This system allows dark current and breakdown studies of different window configurations and materials. The results of this study will be presented. The study has shown that the peak achievable accelerating gradient is reduced by a factor greater than 2 when solenoidal field of greater than 2 T are applied to the cavity.

Moretti, A.; Bross, A.; Geer, S.; Qian, Z.; /Fermilab; Norem, J.; /Argonne; Li, D.; Zisman, M.; /LBL, Berkeley; Torun, Y.; /IIT, Chicago; Rimmer, R.; /Jefferson Lab; Errede,; /Illinois U., Urbana

2005-10-01T23:59:59.000Z

274

A Beale-Kato-Majda breakdown criterion for an Oldroyd-B fluid in the creeping flow regime  

E-Print Network [OSTI]

We derive a criterion for the breakdown of solutions to the Oldroyd-B model in $\\R^3$ in the limit of zero Reynolds number (creeping flow). If the initial stress field is in the Sobolev space $H^m$, $m> 5/2$, then either a unique solution exists within this space indefinitely, or, at the time where the solution breaks down, the time integral of the $L^\\infty$-norm of the stress tensor must diverge. This result is analogous to the celebrated Beale-Kato-Majda breakdown criterion for the inviscid Eluer equations of incompressible fluids.

Raz Kupferman; Claude Mangoubi; Edriss S. Titi

2007-09-10T23:59:59.000Z

275

Single molecule laser spectroscopy  

Science Journals Connector (OSTI)

Abstract In this article, we discussed some single molecule spectroscopy techniques and methods. We have chosen the simplicity in this survey based on our laboratory experience in this field. We concentrated on the imaging by both techniques the wide field and the scanning microscopes. Other imaging enhancements on the technique like extended resolution wide field, the total internal reflection imaging, and its derivatives are also reviewed. In addition to the imaging techniques, some diffusion techniques also are discussed like fluorescence correlation spectroscopy. The related methods like Forester resonance transfer, photo-induced electron transfer and anisotropy (steady state and time decay) are also discussed. In addition, we elucidated some simple details about the theory behind the FCS and its resulting curve fitting. This review is preceded by general introduction and ended with the conclusion.

Diaa Atta; Ali Okasha

2015-01-01T23:59:59.000Z

276

2008 Vibrational Spectroscopy  

SciTech Connect (OSTI)

The conference focuses on using vibrational spectroscopy to probe structure and dynamics of molecules in gases, liquids, and interfaces. The goal is to bring together a collection of researchers who share common interests and who will gain from discussing work at the forefront of several connected areas. The intent is to emphasize the insights and understanding that studies of vibrations provide about a variety of systems.

Philip J. Reid

2009-09-21T23:59:59.000Z

277

Point-contact spectroscopy  

Science Journals Connector (OSTI)

Micro-contacts between metals at low temperatures reveal non-linear structures in the current-voltage characteristics. These deviations from Ohm's law allow an energy-resolved spectroscopy of the interaction of the conduction electrons with elementary excitations (e.g. phonons) in a metal. To explain the method, the important parameters (electron mean free path versus contact dimension) in point-contact spectroscopy will be discussed together with examples of spectroscopic information obtained in various systems. Local temperature gradients in the contact region offer the possibility to study thermo-electric phenomena in small constrictions, such as thermal voltages in non-homogeneous contacts and quenching of the phonon-drag term in the thermo-power in homogeneous contacts. Besides these aspects of the point-contact technique, recent experiments will be shown with applications of point contacts other than just spectroscopy: magneto-resistance of a point contact, high-frequency rectification with a point contact as the non-linear element, electron focusing using a double point-contact set-up, electrical noise in constrictions and generation of phonons by means of point contacts.

A M Duif; A G M Jansen; P Wyder

1989-01-01T23:59:59.000Z

278

Enhancement of RF Breakdown Threshold of Microwave Cavities by Magnetic Insulation  

SciTech Connect (OSTI)

Limitations on the maximum achievable accelerating gradient of microwave cavities can influence the performance, length, and cost of particle accelerators. Gradient limitations are believed to be initiated by electron emission from the cavity surfaces. Here, we show that field emission is effectively suppressed by applying a tangential magnetic field to the cavity walls, so higher gradients can be achieved. Numerical simulations indicate that the magnetic field prevents electrons leaving these surfaces and subsequently picking up energy from the electric field. Our results agree with current experimental data. Two specific examples illustrate the implementation of magnetic insulation into prospective particle accelerator applications. The ultimate goal of several research efforts is to integrate high-gradient radio-frequency (rf) structures into next generation particle accelerators. For instance, the Muon Accelerator Program is looking at developing low-frequency cavities for muon cooling, and the International Linear Collider is optimizing the performance of 1.3 GHz rf structures aimed at designing a 1 TeV electron-positron collider. Furthermore, the High Gradient RF Collaboration is examining high frequency (f > 10 GHz) structures intended for an electron-positron collider operating at energies in the TeV range. In all this research, the accelerating gradient will be one of the crucial parameters affecting their design, construction, and cost. Limitations from rf breakdown strongly influence the development of accelerators since it limits the machine's maximum gradient. The emission of electrons from the cavity surfaces seemingly is a necessary stage in the breakdown process, acting either as a direct cause of breakdown or as precursor for other secondary effects. Typically, electron currents arise from sharp edges or cracks on the cavities surfaces, where the strength of the electric field is strongly enhanced compared to that of the nominal field when the surfaces of the cavity are perfect planes. Subsequently, a stream of emitted electrons can be accelerated by the rf electric field toward the opposing cavity walls. Upon impact, they heat a localized region, resulting in the eventual breakdown by a variety of secondary mechanisms. Therefore, it is advantageous to develop techniques that could suppress field emission within rf cavities. It has been proposed that high voltages up to about a gigavolt range may be sustained in voltage transformers, by adopting the principle of magnetic insulation in ultrahigh vacuum. The basic idea is to suppress field emission by applying a suitably directed magnetic field of sufficient strength to force the electrons orbits back on to the rf emitting surface. More recently, it was shown that magnetic insulation could be very effective in suppressing field emission and multipacting in rectangular coupler waveguides. Hence, the question arises whether the same principle is applicable to rf accelerating structures. In this Letter, we shall consider application of the concept to low-frequency (201-805 MHz) muon accelerator cavities.

Stratakis, D.; Gallardo, J.; Palmer, R.B.

2011-03-28T23:59:59.000Z

279

Dynamics of local micro-breakdown in the Geiger mode of avalanche photodiodes  

SciTech Connect (OSTI)

Mathematical modeling methods were used to study the dynamics of micro-breakdown development in structures of silicon avalanche photodiodes. The constructed model considers the locality of the avalanchexs multiplication region appearing during single photon absorption and the delay of the avalanchexs current spreading over the rear electrode of the diode. The calculations showed two different phases of transient process of the formation of the electrical signal, i.e., the rapid and slow ones due to current spreading and ordinary RC recharge, respectively. The load resistances required to implement the pulsed mode of operation of the structures of the avalanche photodiode were calculated for a series of actual diode capacitances and spreading resistances of the rear electrode.

Verhovtseva, A. V., E-mail: alevteena@gmail.com; Gergel, V. A. [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Russian Federation)], E-mail: gergel@mail.cplire.ru

2009-07-15T23:59:59.000Z

280

Grain-scale thermoelastic stresses and spatiotemporal temperature gradients on airless bodies, implications for rock breakdown  

E-Print Network [OSTI]

Thermomechanical processes such as fatigue and shock have been suggested to cause and contribute to rock breakdown on Earth, and on other planetary bodies, particularly airless bodies in the inner solar system. In this study, we modeled grain-scale stresses induced by diurnal temperature variations on simple microstructures made of pyroxene and plagioclase on various solar system bodies. We found that a heterogeneous microstructure on the Moon experiences peak tensile stresses on the order of 100 MPa. The stresses induced are controlled by the coefficient of thermal expansion and Young's modulus of the mineral constituents, and the average stress within the microstructure is determined by relative volume of each mineral. Amplification of stresses occurs at surface-parallel boundaries between adjacent mineral grains and at the tips of pore spaces. We also found that microscopic spatial and temporal surface temperature gradients do not correlate with high stresses, making them inappropriate proxies for investig...

Molaro, Jamie L; Langer, Steve A

2015-01-01T23:59:59.000Z

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


281

Representing BornOppenheimer breakdown radial correction functions for diatomic molecules  

Science Journals Connector (OSTI)

The empirical determination of BornOppenheimer breakdown (BOB) correction functions from the analysis of high resolution diatomic molecule spectra is becoming increasingly common. However, in virtually all applications to date, the analytic expressions used to represent those functions have unphysical limiting behaviour which makes the resulting overall potential energy functions unusable at long-range. This paper delineates the limiting physical constraints, which should be imposed on the form of such BOB correction functions, and presents flexible new expressions incorporating those constraints. The utility of these new forms is illustrated by a re-analysis of recent high resolution IR data for the ground electronic state of AgH, which yields an updated potential energy function and more meaningful adiabatic (potential) and non-adiabatic (centrifugal) BOB correction functions for this system. Further examination of this AgH system also illustrates the problem of model dependence associated with efforts to determine physically unique potential energy and centrifugal BOB correction functions.

Robert J. Le Roy; Yiye Huang

2002-01-01T23:59:59.000Z

282

Method of Controlling Corona Effects and Breakdown Voltage of Small Air Gaps Stressed by Impulse Voltages  

E-Print Network [OSTI]

This paper investigates the influence of a resistor on the dielectric behavior of an air gap. The resistor is connected in series with the air gap and the latter is stressed by impulse voltage. Air gap arrangements of different geometry with either the rod or the plate grounded are stressed with impulse voltages of both positive and negative polarity. The resistor is connected in series with the air gap in the return circuit connecting the gap with the impulse generator. The method followed involves the investigation of the graphs of the charging time concerning the air gaps capacitances, in connection to the value of the resistor, the geometry of the gap, the effect of grounding and the polarity effect. It is determined that the charging time of the air gap increases, as the value of the resistor increases. It is also determined that the peak voltage value of the fully charged air gap decreases as the value of the resistor increases. The results of the mathematical and simulation analysis are compared with the results of the oscillograms taken from experimental work. In addition and consequently to the above results it is concluded from the experimental work that the in series connection of the resistor in the circuit has significant influence on corona pulses (partial discharges) occurring in the gap and on the breakdown voltage of the gap. A new method of controlling the corona effects and consequently the breakdown voltage of small air gaps stressed by impulse voltage of short duration in connection to the ground effect and the polarity effect has arisen. Furthermore through mathematical analysis of the charging graphs obtained from simulation and experimental oscillograms there was a calculation of the values of the capacitance of the air gaps in relation to their geometry and the results were compared to the values calculated with mathematical analysis.

Athanasios Maglaras; Trifon Kousiouris; Frangiskos Topalis; Dimitrios Katsaros; Leandros A. Maglaras; Konstantina Giannakopoulou

2014-10-15T23:59:59.000Z

283

IONIZATION IN ATMOSPHERES OF BROWN DWARFS AND EXTRASOLAR PLANETS. III. BREAKDOWN CONDITIONS FOR MINERAL CLOUDS  

SciTech Connect (OSTI)

Electric discharges were detected directly in the cloudy atmospheres of Earth, Jupiter, and Saturn, are debatable for Venus, and indirectly inferred for Neptune and Uranus in our solar system. Sprites (and other types of transient luminous events) have been detected only on Earth, and are theoretically predicted for Jupiter, Saturn, and Venus. Cloud formation is a common phenomenon in ultra-cool atmospheres such as in brown dwarf and extrasolar planetary atmospheres. Cloud particles can be expected to carry considerable charges which may trigger discharge events via small-scale processes between individual cloud particles (intra-cloud discharges) or large-scale processes between clouds (inter-cloud discharges). We investigate electrostatic breakdown characteristics, like critical field strengths and critical charge densities per surface, to demonstrate under which conditions mineral clouds undergo electric discharge events which may trigger or be responsible for sporadic X-ray emission. We apply results from our kinetic dust cloud formation model that is part of the DRIFT-PHOENIX model atmosphere simulations. We present a first investigation of the dependence of the breakdown conditions in brown dwarf and giant gas exoplanets on the local gas-phase chemistry, the effective temperature, and primordial gas-phase metallicity. Our results suggest that different intra-cloud discharge processes dominate at different heights inside mineral clouds: local coronal (point discharges) and small-scale sparks at the bottom region of the cloud where the gas density is high, and flow discharges and large-scale sparks near, and maybe above, the cloud top. The comparison of the thermal degree of ionization and the number density of cloud particles allows us to suggest the efficiency with which discharges will occur in planetary atmospheres.

Helling, Ch.; Jardine, M.; Stark, C. [SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS (United Kingdom); Diver, D., E-mail: ch@leap2010.eu [SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

2013-04-20T23:59:59.000Z

284

518 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 33, NO. 2, APRIL 2005 Plasma Dynamics During Breakdown in  

E-Print Network [OSTI]

, lamp, modeling, plasma. METAL halide arc lamps are widely used sources of in- door and large area plasma hydrodynamics model was used to investigate breakdown in metal halide lamp. Images depicting518 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 33, NO. 2, APRIL 2005 Plasma Dynamics During

Kushner, Mark

285

Towards a better understanding of dielectric barrier discharges in ferroelectrets: Paschen breakdown fields in micrometer sized voids  

SciTech Connect (OSTI)

Charged cellular polypropylene foams (i.e., ferro- or piezoelectrets) demonstrate high piezoelectric activity upon being electrically charged. When an external electric field is applied, dielectric barrier discharges (DBDs) occur, resulting in a separation of charges which are subsequently deposited on dielectric surfaces of internal micrometer sized voids. This deposited space charge is responsible for the piezoelectric activity of the material. Previous studies have indicated charging fields larger than predicted by Townsend's model of Paschen breakdown applied to a multilayered electromechanical model; a discrepancy which prompted the present study. The actual breakdown fields for micrometer sized voids were determined by constructing single cell voids using polypropylene spacers with heights ranging from 8 to 75??m, sandwiched between two polypropylene dielectric barriers and glass slides with semi-transparent electrodes. Subsequently, a bipolar triangular charging waveform with a peak voltage of 6?kV was applied to the samples. The breakdown fields were determined by monitoring the emission of light due to the onset of DBDs using an electron multiplying CCD camera. The breakdown fields at absolute pressures from 101 to 251?kPa were found to be in good agreement with the standard Paschen curves. Additionally, the magnitude of the light emission was found to scale linearly with the amount of gas, i.e., the height of the voids. Emissions were homogeneous over the observed regions of the voids for voids with heights of 25??m or less and increasingly inhomogeneous for void heights greater than 40??m at high electric fields.

Harris, Scott, E-mail: harri4s@cmich.edu [Department of Physics and Science of Advanced Materials Program, Central Michigan University, Mount Pleasant, Michigan 48859 (United States); Applied Condensed-Matter Physics, Department of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm (Germany); Mellinger, Axel, E-mail: axel.mellinger@cmich.edu [Department of Physics and Science of Advanced Materials Program, Central Michigan University, Mount Pleasant, Michigan 48859 (United States)

2014-04-28T23:59:59.000Z

286

Dead-Space Theory Predictions of Excess-Noise Factor, Breakdown Voltage, and Frequency Response for Thin Avalanche Photodiodes  

E-Print Network [OSTI]

for Thin Avalanche Photodiodes Majeed M. Hayat°", Mohammad A. Sa1eh', Ohhyun Kwonc, Bahaa E. A. Sale width. Keywords: Avalanche photodiode, dead space, impact ionization, excess noise factor, avalanche breakdown down, frequency response. 1 Introduction It is well known that for avalanche photodiodes (APDs

Teich, Malvin C.

287

High Breakdown ( > \\hbox {1500 V} ) AlGaN/GaN HEMTs by Substrate-Transfer Technology  

E-Print Network [OSTI]

In this letter, we present a new technology to increase the breakdown voltage of AlGaN/GaN high-electron-mobility transistors (HEMTs) grown on Si substrates. This new technology is based on the removal of the original Si ...

Lu, Bin

288

Excitational energy transfer enhancing ionization and spatial-temporal evolution of air breakdown with UV laser radiation  

E-Print Network [OSTI]

with UV laser radiation Jason S. Hummelta and John E. Scharer Department of Electrical and Computer of oxygen has on the ionization of nitrogen in laser air breakdown. Plasma is created by focusing a 193 nm ArF excimer laser using an 18 cm focal length lens, producing a cylindrical 540 m wide spot

Scharer, John E.

289

Detection-estimation of very close emitters: performance breakdown, ambiguity, and general statistical analysis of maximum-likelihood estimation  

Science Journals Connector (OSTI)

We reexamine the well-known problem of "threshold behavior" or "performance breakdown" in the detection-estimation of very closely spaced emitters. In this extreme regime, we analyze the performance for maximum-likelihood estimation (MLE) of directions-of-arrival ... Keywords: direction-of-arrival (DOA) estimation, maximum-likelihood estimation, random matrix theory, signal detection, signal resolution

Yuri I. Abramovich; Ben A. Johnson

2010-07-01T23:59:59.000Z

290

The role of boundary conditions in a simple model of incipient vortex breakdown F. Gallaire and J.-M. Chomaz  

E-Print Network [OSTI]

. In the labora- tory, it is preferentially studied in vortex tubes, where it is seen in many cases to give riseThe role of boundary conditions in a simple model of incipient vortex breakdown F. Gallaire and J of a hairpin vortex in a shear-thinning fluid governed by a power-law model Phys. Fluids 25, 101703 (2013); 10

Boyer, Edmond

291

(Resonance ionization spectroscopy)  

SciTech Connect (OSTI)

J. P. Young attended the Fifth International Symposium on Resonance Ionization Spectroscopy and presented an invited oral presentation on research he and coworkers had carried out in applying diode lasers to resonance ionization mass spectrometry. A summary of the conference is given along with an assessment of some of the presentations that the author found of interest. Young also visited Professor Marassi at the University of Camerino to present a seminar and discuss mutual interests in a new molten salt research project of the author. Some of the studies at Camerino are described. Ideas concerning the author's research that came from private discussions are also presented here.

Young, J.P.

1990-10-11T23:59:59.000Z

292

Rapid breakdown anodization technique for the synthesis of high aspect ratio and high surface area anatase TiO{sub 2} nanotube powders  

SciTech Connect (OSTI)

Clusters of high aspect ratio, high surface area anatase-TiO{sub 2} nanotubes with a typical nanotube outer diameter of about 18 nm, wall thickness of approximately 5 nm and length of 5-10 {mu}m were synthesized, in powder form, by breakdown anodization of Ti foils in 0.1 M perchloric acid, at 10 V (299 K) and 20 V ({approx}275 and 299 K). The surface area, morphology, structure and band gap were determined from Brunauer Emmet Teller method, field emmission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman, photoluminescence and diffuse reflectance spectroscopic studies. The tubular morphology and anatase phase were found to be stable up to 773 K and above 773 K anatase phase gradually transformed to rutile phase with disintegration of tubular morphology. At 973 K, complete transformation to rutile phase and disintegration of tubular morphology were observed. The band gap of the as prepared and the annealed samples varied from 3.07 to 2.95 eV with increase in annealing temperature as inferred from photoluminescence and diffuse reflectance studies. -- Graphical abstract: Display Omitted Research highlights: {yields} High aspect ratio anatase-titania nanotube powders were synthesized electrochemically. {yields} The surface area of the nanotubes were much higher than those reported. {yields} The annealing temperature limit for maintaining tubular morphology was established. {yields} The photoluminiscence spectroscopy reflected the presence of defects, annealing of defects and phase transformation. {yields} The nanotubes were of {approx}5 nm wall thickness as revealed by TEM studies.

Antony, Rajini P. [Thin Films and Coatings Section, Surface and Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Mathews, Tom, E-mail: tom@igcar.gov.i [Thin Films and Coatings Section, Surface and Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Dasgupta, Arup [Physical Metallurgy Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Dash, S.; Tyagi, A.K. [Thin Films and Coatings Section, Surface and Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Raj, Baldev [Thin Films and Coatings Section, Surface and Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Physical Metallurgy Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India)

2011-03-15T23:59:59.000Z

293

Quantitative analysis of tin alloy combined with artificial neural network prediction  

SciTech Connect (OSTI)

Laser-induced breakdown spectroscopy was applied to quantitative analysis of three impurities in Sn alloy. The impurities analysis was based on the internal standard method using the Sn I 333.062-nm line as the reference line to achieve the best reproducible results. Minor-element concentrations (Ag, Cu, Pb) in the alloy were comparatively evaluated by artificial neural networks (ANNs) and calibration curves. ANN was found to effectively predict elemental concentrations with a trend of nonlinear growth due to self-absorption. The limits of detection for Ag, Cu, and Pb in Sn alloy were determined to be 29, 197, and 213 ppm, respectively.

Oh, Seong Y.; Yueh, Fang-Yu; Singh, Jagdish P.

2010-05-01T23:59:59.000Z

294

Automated Interpretation of LIBS Spectra using a Fuzzy Logic Inference Engine  

SciTech Connect (OSTI)

Automated interpretation of laser-induced breakdown spectroscopy (LIBS) data is necessary due to the plethora of spectra that can be acquired in a relatively short time. However, traditional chemometric and artificial neural network methods that have been employed are not always transparent to a skilled user. A fuzzy logic approach to data interpretation has now been adapted to LIBS spectral interpretation. A fuzzy logic inference engine (FLIE) was used to differentiate between various copper containing and stainless steel alloys as well as unknowns. Results using FLIE indicate a high degree of confidence in spectral assignment.

Jeremy J. Hatch; Timothy R. McJunkin; Cynthia Hanson; Jill R. Scott

2012-02-01T23:59:59.000Z

295

The light meson spectroscopy program  

SciTech Connect (OSTI)

Recent discoveries of a number of unexpected new charmomium-like meson states at the BaBar and Belle B-factories have demonstrated how little is still known about meson spectroscopy. In this talk we will review recent highlights of the light quark spectroscopy from collider and fixed target experiments.

Smith, Elton S. [JLAB

2014-06-01T23:59:59.000Z

296

SMB, X-ray Emission Spectroscopy  

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

Emission Spectroscopy Beam Line 6-2b X-ray Emission Spectroscopy Beam Line 6-2b is an advanced spectroscopy experimental station on the multidisciplinary general user wiggler Beam...

297

SMB, X-Ray Spectroscopy & Imaging  

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

Home X-Ray Spectroscopy & Imaging X-Ray Spectroscopy & Imaging SSRL has five hard X-ray Spectroscopy beamlines and three Microfocus Imaging beamlines dedicated to Biological and...

298

An investigation into the cumulative breakdown process of polymethylmethacrylate in quasi-uniform electric field under nanosecond pulses  

SciTech Connect (OSTI)

A group of complete images on the discharge channel developed in PMMA in quasi-uniform electric field under nanosecond pulses are observed with an on-line transmission microscope. The characteristics of the cumulative breakdown process are also generalized, which include initiating from the vicinity of the cathode, developing to the anode with a branch-like shape, and taking on a wormhole appearance when final breakdown occurs. The concluded characteristics are explained by referring to the conceptions of low density domain and free radical and considering the initial discharge channel as a virtual needle. The characteristics are helpful for designers to enhance the lifetime of insulators employed on a nanosecond time scale.

Zhao, Liang; Cang Su, Jian; Bo Zhang, Xi; Feng Pan, Ya; Min Wang, Li; Peng Fang, Jin; Sun, Xu; Lui, Rui [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, P.O. Box 69 Branch 13, Xi'an 710024 (China)] [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, P.O. Box 69 Branch 13, Xi'an 710024 (China)

2013-08-15T23:59:59.000Z

299

Breakdown of the Equivalence between Energy Content and Weight in a Weak Gravitational Field for a Quantum Body  

E-Print Network [OSTI]

It is shown that weight operator of a composite quantum body in a weak external gravitational field in the post-Newtonian approximation of the General Relativity does not commute with its energy operator, taken in the absence of the field. Nevertheless, the weak equivalence between the expectations values of weight and energy is shown to survive at a macroscopic level for stationary quantum states for the simplest composite quantum body - a hydrogen atom. Breakdown of the weak equivalence between weight and energy at a microscopic level for stationary quantum states can be experimentally detected by studying unusual electromagnetic radiation, emitted by the atoms, supported and moved in the Earth gravitational field with constant velocity, using spacecraft or satellite. For superpositions of stationary quantum states, a breakdown of the above mentioned equivalence at a macroscopic level leads to time dependent oscillations of the expectation values of weight, where the equivalence restores after averaging over time procedure.

Andrei Lebed

2012-05-14T23:59:59.000Z

300

VERY LOW FREQUENCY BREAKDOWN PROPERTIES OF ELECTRICAL INSULATION MATERIALS AT CRYOGENIC TEMPERATURES  

SciTech Connect (OSTI)

For long cables or equipment with large capacitance it is not always possible to conduct high voltage withstand at tests at 60 Hz due to limitations in charging currents of the power supply. Very low frequency (typically at a frequency of 0.1 Hz) has been used for conventional cables as a way of getting around the charging current limitation. For superconducting grid applications the same issues apply. However there is very little data at cryogenic temperatures on how materials perform at low frequency compared to 60 Hz and whether higher voltages should be applied when performing a high voltage acceptability test. Various materials including G10 (fiberglass reinforced plastic or FRP), Cryoflex (a tape insulation used in some high temperature superconducting cables), kapton (commonly used polyimide), polycarbonate, and polyetherimide, and in liquid nitrogen alone have been tested using a step method for frequencies of 60 Hz, 0.1 Hz, and dc. The dwell time at each step was chosen so that the aging factor would be the same in both the 60 Hz and 0.1 Hz tests. The data indicated that, while there is a small frequency dependence for liquid nitrogen, there are significant differences for the solid materials studied. Breakdown data for these materials and for model cables will be shown and discussed.

Sauers, Isidor [ORNL; Tuncer, Enis [ORNL; Polyzos, Georgios [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL; Pace, Marshall O [ORNL

2010-01-01T23:59:59.000Z

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


301

High altitude atmospheric discharges according to the runaway air breakdown mechanism  

SciTech Connect (OSTI)

High altitude optical transients - red sprites, blue jets, and elves - are modeled in the context of the relativistic electron runaway air breakdown mechanism. These emissions are usually associated with large mesoscale convective systems (hereafter MCS). In thunderstorms cloud electrification proceeds over a time scale long enough to permit the conducting atmosphere above the cloud to polarize and short out the thunderstorm electric field. When a lightning strike rapidly neutralizes a cloud charge layer runaway driving fields can develop in the stratosphere and mesosphere. According to present simulations of the full runaway process the variety of observed optical emissions are due to the nature of the normal lightning event in the MCS that kick starts the runaway avalanche. In this paper the authors describe some details of the model, present the results of the evolution of the primary electron population, and summarize the initial conditions necessary for different types of discharges. Two companion papers present (a) the predicted optical, gamma ray, and radio emissions caused by these electrical discharges, and (b) the time evolution of the secondary electron population and its implications in terms of observables.

Symbalisty, E.; Roussel-Dupre, R.; Yukhimuk, V.; Taranenko, Y.

1997-04-01T23:59:59.000Z

302

X-ray Photoelectron Spectroscopy (XPS) | EMSL  

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

photoelectron spectroscopy (UPS), ion scattering spectroscopy (ISS), a clusterAr+ ion gun, and a five-axis automated stage with variable temperature sample environment at the...

303

Sum Frequency Generation for Surface Vibrational Spectroscopy...  

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

Sum Frequency Generation for Surface Vibrational Spectroscopy Sum Frequency Generation for Surface Vibrational Spectroscopy This customized SFG-VS spectrometer incorporates unique...

304

Numerical studies of the high power microwave breakdown in gas using the fluid model with a modified electron energy distribution function  

SciTech Connect (OSTI)

A modified electron energy distribution function (EEDF) is introduced into the fluid model and its effects on the high power microwave (HPM) breakdown in air and argon are investigated. A proper numerical scheme for the finite-difference time-domain method is employed to solve the fluid model. Numerical simulations show that the HPM breakdown time in argon predicted by the fluid model with the modified EEDF agrees well with the results of Particle-in-cell-Monte Carlo collision simulations, while the Maxwellian EEDF results in faster HPM breakdown when the mean electron energy is less than 20 eV. We also confirm that the Maxwellian EEDF can be used in the fluid model for simulating the air breakdown at the low frequencies based on the reported experiments.

Zhao Pengcheng; Liao Cheng; Lin Chenbin; Chang Lei; Fu Haijun [Institute of Electromagnetics, Southwest Jiaotong University, Chengdu 610031 (China)

2011-10-15T23:59:59.000Z

305

Spectroscopy of Rf257  

Science Journals Connector (OSTI)

The isotope Rf257 was produced in the fusion-evaporation reaction Pb208(Ti50,n)Rf257. Reaction products were separated and identified by mass. Delayed spectroscopy of Rf257 and its decay products was performed. A partial decay scheme with configuration assignments is proposed based on ? hindrance factors. The excitation energy of the 1/2+[620] configuration in No253 is proposed. The energy of this 1/2+ state in a series of N=151 isotones increases with nuclear charge, reflecting an increase in the N=152 gap. This gap is deduced to grow substantially from 850 to 1400 keV between Z=94 and 102. An isomeric state in Rf257, with a half-life of 160-31+42??s, was discovered by detecting internal conversion electrons followed by ? decay. It is interpreted as a three-quasiparticle high-K isomer. A second group of internal conversion electrons, with a half-life of 4.1-1.3+2.4 s, followed by ? decay, was also observed. These events might originate from the decay of excited states in Lr257, populated by electron-capture decay of Rf257. Fission of Rf257 was unambiguously detected, with a branching ratio of bRfSF=0.020.01.

J. Qian; A. Heinz; T. L. Khoo; R. V. F. Janssens; D. Peterson; D. Seweryniak; I. Ahmad; M. Asai; B. B. Back; M. P. Carpenter; A. B. Garnsworthy; J. P. Greene; A. A. Hecht; C. L. Jiang; F. G. Kondev; T. Lauritsen; C. J. Lister; A. Robinson; G. Savard; R. Scott; R. Vondrasek; X. Wang; R. Winkler; S. Zhu

2009-06-22T23:59:59.000Z

306

Measurements of the volt-ampere characteristics and the breakdown voltages of direct-current helium and hydrogen discharges in microgaps  

SciTech Connect (OSTI)

The discharge phenomena for micro meter gap sizes include many interesting problems from engineering and physical perspectives. In this paper, the authors deal with the experimental and theoretical results of the breakdown voltage and current-voltage characteristics of the direct-current helium and hydrogen discharges. The measurements were performed at a constant pressure of around one atmosphere, while varying the gap size between two parallel plane tungsten electrodes between 1??m and 100??m. From the measured breakdown voltage curves, the effective yields and the ionization coefficients were derived for both gases. Present data for the ionization coefficients correlate with the data obtained for the breakdown voltage curves measured for fixed 100??m interelectrode separation. The current-voltage characteristics were plotted for the various gap sizes illustrating the role of the field emission effects in the microgaps. Based on the Fowler-Nordheim theory, the enhancement factors were determined. The gap spacing dependence of the field emission current can be explained by the introduction of two ideas, the first being a space charge effect by emitted electrons, and the second a change in the breakdown mechanism. Experimental results, presented here, demonstrate that Townsend phenomenology breaks down when field emission becomes the key mechanism affecting the breakdown and deforming the left hand side of the breakdown voltage curves.

Klas, M.; Matej?ik, . [Department of Experimental Physics, Comenius University, Mlynskadolina F2, 84248 Bratislava (Slovakia); Radjenovi?, B.; Radmilovi?-Radjenovi?, M. [Institute of Physics, University of Belgrade, P.O. Box 57, 11080 Belgrade (Serbia)

2014-10-15T23:59:59.000Z

307

Raman Spectroscopy of Microbial Pigments  

Science Journals Connector (OSTI)

...minireview, Raman spectroscopy has several advantages for pigment and carotenoid work. The...BF01923559 . 71. Garcia-Pichel, F . 1998. Solar ultraviolet and the evolutionary history...signal strength, adaptive strategies, solar radiation, and humidity. Astrobiology...

Jan Jehli?ka; Howell G. M. Edwards; Aharon Oren

2014-03-28T23:59:59.000Z

308

Ring resonant cavities for spectroscopy  

DOE Patents [OSTI]

Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS). 6 figs.

Zare, R.N.; Martin, J.; Paldus, B.A.; Xie, J.

1999-06-15T23:59:59.000Z

309

Transient Absorption Spectroscopy with Isolated Attosecond Pulses  

E-Print Network [OSTI]

viii Attosecond transient absorption instrument. . . . . .5.2.2 AbsorptionTransient absorption spectroscopy . . . . . . . . . . . .

Bell, Marie Justine

2013-01-01T23:59:59.000Z

310

Spectroscopy (XSD) | Advanced Photon Source  

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

Useful Links Useful Links Spectroscopy Group (X-ray Science Division) The Spectroscopy Group operates the Sector-20 bending magnet (BM) and insertion device (ID) beamlines, and the bending magnet beamline at Sector-9. Beamlines 20-ID (Undulator A) Supported Techniques ·X-ray absorption fine structure (XAFS) ·Surface Diffraction ·X-ray Raman Scattering ·Resonant X-ray Emission Spectroscopy ·Micro-XAFS ·Confocal X-ray microscopy ·Micro-fluorescence ·Micro-XRD Discipline ·Material Science ·Environmental Science ·Chemistry Click [20-ID] under "Beamlines" above for technical information 20-BM Supported Techniques X-ray absorption fine structure (XAFS) Micro-fluorescence Micro-XAFS Micro-diffraction Discipline ·Material Science ·Environmental Science ·Chemistry Click [20-BM] under "Beamlines" above for technical information

311

Environmental Spectroscopy and Biogeochemistry Facility  

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

ES&B Overview ES&B Overview Section 2-2-1 Environmental Spectroscopy and Biogeochemistry Facility The Environmental Spectroscopy and Biogeochemistry (ES&B) Facility focuses on environ- mental molecular science and application of the fundamental concepts of physical chemistry to the study of chemical reactions in heterogeneous natural materials, with an emphasis on soil and subsurface systems. The ES&B Facility staff, along with other Pacific Northwest National Laboratory (PNNL) staff, form a multidisciplinary research team with expertise in chemistry, mineral physics, geochemistry, soil chemistry, microbiology, hydrology, and environmental engineering. Capabilities Capabilities are available for materials characterization, aqueous- and solid-phase speciation

312

X-ray Absorption Spectroscopy  

SciTech Connect (OSTI)

This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

Yano, Junko; Yachandra, Vittal K.

2009-07-09T23:59:59.000Z

313

Adiabatic Tip-Plasmon Focusing for Nano-Raman Spectroscopy. ...  

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

Adiabatic Tip-Plasmon Focusing for Nano-Raman Spectroscopy. Adiabatic Tip-Plasmon Focusing for Nano-Raman Spectroscopy. Abstract: True nanoscale optical spectroscopy requires the...

314

7 - Raman spectroscopy of graphene  

Science Journals Connector (OSTI)

Abstract: The principles of Raman scattering and the properties of phonons and electrons in graphene are reviewed. The focus is on Raman spectroscopy of mono- and bilayer graphene, particularly perturbations that have a significant influence on the Raman spectra. The distinct behaviour of Raman modes of different orders is discussed.

M. Hulman

2014-01-01T23:59:59.000Z

315

Cryogenic Ion Chemistry and Spectroscopy  

Science Journals Connector (OSTI)

Cryogenic Ion Chemistry and Spectroscopy ... His research focuses on developing and applying cryogenic ion processing for the characterization of hydrogen bonding motifs in macromolecules and activated organometallic catalysts. ... In this Account, we discuss how cryogenic cooling, mass selection, and reactive processing together provide a powerful way to characterize ion structures as well as rationally synthesize labile reaction intermediates. ...

Arron B. Wolk; Christopher M. Leavitt; Etienne Garand; Mark A. Johnson

2013-08-23T23:59:59.000Z

316

2014 Journal Articles  

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

Optics Demos, SG., et al., "Dynamics of the plume containing nanometric-sized particles ejected into the atmospheric air following laser-induced breakdown on the exit surface of a...

317

2014 Journal Articles  

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

NIF Facility R&D Demos, SG., et al., "Dynamics of the plume containing nanometric-sized particles ejected into the atmospheric air following laser-induced breakdown on the exit...

318

Stark spectroscopy on rare gas atoms  

E-Print Network [OSTI]

Stark spectroscopy on rare gas atoms PROEFSCHRIFT ter verkrijging van de graad van doctor aan de-DATA LIBRARY TECHNISCHE UNIVERSITEIT EINDHOVEN Jiang, Tao Stark spectroscopy on rare gas atoms / by Tao Jiang / gasontladingen Subject headings : plasma diagnostics / Stark effect / optogalvanic spectroscopy / atomic emission

Eindhoven, Technische Universiteit

319

X-Ray Absorption Spectroscopy of Metallobiomolecules  

E-Print Network [OSTI]

2/9/07 1 X-Ray Absorption Spectroscopy of Metallobiomolecules The Outskirts of Structural Biology 9, 07] This is a tutorial about the use of X-ray Absorption Spectroscopy (XAS) in biology, RG; Eisenberger, P; Kincaid, BM "X-ray Absorption Spectroscopy of Biological Molecules" Annu. Rev

Scott, Robert A.

320

X-Ray Absorption Spectroscopy of Metallobiomolecules  

E-Print Network [OSTI]

9/6/09 1 X-Ray Absorption Spectroscopy of Metallobiomolecules The Outskirts of Structural Biology 6, 09] This is a tutorial about the use of X-ray Absorption Spectroscopy (XAS) in biology, RG; Eisenberger, P; Kincaid, BM "X-ray Absorption Spectroscopy of Biological Molecules" Annu. Rev

Scott, Robert A.

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


321

Resonance emission spectroscopy of predissociating SO2 C~ ,,1 1 Coupling with a repulsive 1  

E-Print Network [OSTI]

absorption and fluorescence excitation spectra of the C~ X~ transition under bulb conditions at room temperature and showed clearly that the fluorescence intensity drops abruptly for ex- citation wavelengths. They observed the laser-induced fluores- cence LIF spectrum of jet-cooled SO2 and reported the pre- dissociation

Butler, Laurie J.

322

High-Speed Optical Spectroscopy  

E-Print Network [OSTI]

The large surveys and sensitive instruments of modern astronomy are turning ever more examples of variable objects, many of which are extending the parameter space to testing theories of stellar evolution and accretion. Future projects such as the Laser Interferometer Space Antenna (LISA) and the Large Synoptic Survey Telescope (LSST) will only add more challenging candidates to this list. Understanding such objects often requires fast spectroscopy, but the trend for ever larger detectors makes this difficult. In this contribution I outline the science made possible by high-speed spectroscopy, and consider how a combination of the well-known progress in computer technology combined with recent advances in CCD detectors may finally enable it to become a standard tool of astrophysics.

T. R. Marsh

2007-06-28T23:59:59.000Z

323

Spectroscopy with Multichannel Correlation Radiometers  

E-Print Network [OSTI]

Correlation radiometers make true differential measurements in power with high accuracy and small systematic errors. This receiver architecture has been used in radio astronomy for measurements of continuum radiation for over 50 years; this article examines spectroscopy over broad bandwidths using correlation techniques. After general discussions of correlation and the choice of hybrid phase, experimental results from tests with a simple laboratory multi-channel correlation radiometer are shown. Analysis of the effect of the input hybrid's phase shows that a 90 degree hybrid is likely to be the best general choice for radio astronomy, depending on its amplitude match and phase flatness with frequency. The laboratory results verify that the combination of the correlation architecture and an analog lag correlator is an excellent method for spectroscopy over very wide bandwidths.

A. I. Harris

2005-04-20T23:59:59.000Z

324

Quantitative tunneling spectroscopy of nanocrystals  

SciTech Connect (OSTI)

The proposed goals of this collaborative work were to systematically characterize the electronic structure and dynamics of 3-dimensional metal and semiconducting nanocrystals using scanning tunneling microscopy/spectroscopy (STM/STS) and ballistic electron emission spectroscopy (BEES). This report describes progress in the spectroscopic work and in the development of methods for creating and characterizing gold nanocrystals. During the grant period, substantial effort also was devoted to the development of epitaxial graphene (EG), a very promising materials system with outstanding potential for nanometer-scale ballistic and coherent devices ("graphene" refers to one atomic layer of graphitic, sp2 -bonded carbon atoms [or more loosely, few layers]). Funding from this DOE grant was critical for the initial development of epitaxial graphene for nanoelectronics

First, Phillip N; Whetten, Robert L; Schaaff, T Gregory

2007-05-25T23:59:59.000Z

325

Born-Oppenheimer breakdown effects and hyperfine structure in the rotational spectra of SbF and SbCl  

Science Journals Connector (OSTI)

Pure rotational spectra have been measured for the ground electronic states of SbF and SbCl. The molecules were prepared by laser ablation of Sb metal in the presence of SF6 or Cl2, respectively. Their spectra were measured with a cavity pulsed jet Fourier transform microwave spectrometer. Although both molecules have two unpaired electrons, they are subject to Hunds coupling case (c), and have X10+ ground states. The spectra have been interpreted with the formalism of 1?+ molecules. For both molecules spectra of several isotopomers have been measured in the ground and first excited vibrational states. Large hyperfine splittings attributable to both nuclear quadrupole coupling and nuclear spin-rotation coupling have been observed. A Dunham-type analysis has produced unusually large Born-Oppenheimer breakdown parameters, which are interpreted in terms of the electronic structures of the molecules.

Stephen A. Cooke; Michael C.L. Gerry

2005-01-01T23:59:59.000Z

326

Experimental observation of breakdowns in the Fermilab RF Gun G4 J.-P. Carneiro1, D. Edwards2, I. Gonin2, S. Schreiber1  

E-Print Network [OSTI]

Experimental observation of breakdowns in the Fermilab RF Gun G4 J.-P. Carneiro1, D. Edwards2, I Fermilab has developed and delivered to DESY Hamburg two RF guns for the operation of the phase I of the TESLA Test Facility (TTF) accelerator. The first RF gun (designated G3 in the following) has been

327

Atomic Spectroscopy and Separated Isotopes  

Science Journals Connector (OSTI)

The advantages in the use of separated isotopes in atomic spectroscopy for the determination of nuclear momentsI ? Q and for studies of the isotope-shift phenomena are discussed. Illustrations of spectra are given for mercury uranium and samarium. In addition a summary is given of twenty-two so-called problem nuclei i.e. those naturally occurring isotopes for which the nuclear moments are completely uncertain. Concluding remarks are made on such problems as the evaluation of the absolute magnitude of isotope shifts the role of forbidden transitions in isotope spectra and the potential future value of spectro-isotopic assay techniques.

J. R. McNally Jr.

1952-01-01T23:59:59.000Z

328

1 - Fundamentals of optical spectroscopy  

Science Journals Connector (OSTI)

Abstract: This chapter discusses the electronic, vibrational, and rotational spectroscopy of atoms and molecules, and the relationship between the concentration of a species and its spectral intensities. The different types of radiative transitions and spectral broadening mechanisms are discussed. A brief review of energy levels and selection rules for radiative transitions and hence allowed spectroscopic transitions for both atoms and molecules are presented. The determination of the plasma temperature and the temperatures of molecular degrees of freedom from spectroscopic observations is addressed. The effect of spectral congestion is illustrated through the display of simulated spectra at different resolutions.

P.J. Dagdigian

2014-01-01T23:59:59.000Z

329

Combining Feedback Absorption Spectroscopy, Amplified Resonance...  

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

On-Board Measurement of Ammonia and Nitrous Oxide Using Feedback Absorption Laser Spectroscopy Combined with Amplified Resonance and Low Pressure Sampling Cummins...

330

Terahertz spectroscopy for quantifying refined oil mixtures  

Science Journals Connector (OSTI)

In this paper, the absorption coefficient spectra of samples prepared as mixtures of gasoline and diesel in different proportions are obtained by terahertz time-domain spectroscopy. To...

Li, Yi-nan; Li, Jian; Zeng, Zhou-mo; Li, Jie; Tian, Zhen; Wang, Wei-kui

2012-01-01T23:59:59.000Z

331

RIJKSUNIVERSITEIT GRONINGEN Mid-Infrared Spectroscopy of  

E-Print Network [OSTI]

RIJKSUNIVERSITEIT GRONINGEN Mid-Infrared Spectroscopy of Dusty Galactic Nuclei PROEFSCHRIFT ter verkrijging van het doctoraat in de Wiskunde en Natuurwetenschappen aan de Rijksuniversiteit Groningen op

Spoon, Henrik

332

VARIOUS APPLICATIONS OF ZEEMAN ATOMIC ABSORPTION SPECTROSCOPY  

E-Print Network [OSTI]

APPLICATIONS OF ZEEMAN ATOMIC ABSORPTION SPECTROSCOPYthe Zeeman effect to atomic absorption spectroscopy has beenthe Zeeman effect on atomic absorption spectrometry has been

Koizumi, Hideaki

2011-01-01T23:59:59.000Z

333

Nonlinear Spectroscopy of Trapped Ions  

E-Print Network [OSTI]

Nonlinear spectroscopy employs a series of laser pulses to interrogate dynamics in large interacting many-body systems, and has become a highly successful method for experiments in chemical physics. Current quantum optical experiments approach system sizes and levels of complexity which require the development of efficient techniques to assess spectral and dynamical features with scalable experimental overhead. However, established methods from optical spectroscopy of macroscopic ensembles cannot be applied straightforwardly to few-atom systems. Based on the ideas proposed in [M. Gessner et al. New J. Phys. 16 092001 (2014)], we develop a diagrammatic approach to construct nonlinear measurement protocols for controlled quantum systems and discuss experimental implementations with trapped ion technology in detail. These methods in combination with distinct features of ultra-cold matter systems allow us to monitor and analyze excitation dynamics in both the electronic and vibrational degrees of freedom. They are independent of system size, and can therefore reliably probe systems where, e.g., quantum state tomography becomes prohibitively expensive. We propose signals that can probe steady state currents, detect the influence of anharmonicities on phonon transport, and identify signatures of chaotic dynamics near a quantum phase transition in an Ising-type spin chain.

Frank Schlawin; Manuel Gessner; Shaul Mukamel; Andreas Buchleitner

2014-10-07T23:59:59.000Z

334

Publications  

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

7 results: 7 results: BibTex RIS RTF XML Sort by: Author Title Type [ Year (Desc) ] Filters: Author is Alberto J. Fernandez [Clear All Filters] 2009 Piscitelli, Vincent, Mauro A. Martinez, Alberto J. Fernandez, Jhanis J. Gonzalez, Xianglei Mao, and Richard E. Russo. "Double pulse laser induced breakdown spectroscopy; experimental study of lead emission intensity dependence on the wavelengths and sample matrix." Spectrochimica Acta Part B 64, no. 2 (2009): 147-154. 2008 Gonzalez, Jhanis J., Alberto J. Fernandez, Dayana Oropeza, Xianglei Mao, and Richard E. Russo. "Femtosecond laser ablation: Experimental study of the repetition rate influence on qualitative and quantitative ICP-MS performance." Spectrochimica Acta Part B-Atomic Spectroscopy 63 (2008):

335

E-Print Network 3.0 - analytical atomic spectroscopy Sample Search...  

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

A partial sampling of these techniques includes: Absorption spectroscopy Atomic absorption... spectroscopy Atomic emission spectroscopy Atomic fluorescence...

336

E-Print Network 3.0 - atomic spectroscopy technologies Sample...  

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

A partial sampling of these techniques includes: Absorption spectroscopy Atomic absorption... spectroscopy Atomic emission spectroscopy Atomic fluorescence...

337

Effects of Combustion-Induced Vortex Breakdown on Flashback Limits of Syngas-Fueled Gas Turbine Combustors  

SciTech Connect (OSTI)

Turbine combustors of advanced power systems have goals to achieve very low pollutants emissions, fuel variability, and fuel flexibility. Future generation gas turbine combustors should tolerate fuel compositions ranging from natural gas to a broad range of syngas without sacrificing operational advantages and low emission characteristics. Additionally, current designs of advanced turbine combustors use various degrees of swirl and lean premixing for stabilizing flames and controlling high temperature NOx formation zones. However, issues of fuel variability and NOx control through premixing also bring a number of concerns, especially combustor flashback and flame blowout. Flashback is a combustion condition at which the flame propagates upstream against the gas stream into the burner tube. Flashback is a critical issue for premixed combustor designs, because it not only causes serious hardware damages but also increases pollutant emissions. In swirl stabilized lean premixed turbine combustors onset of flashback may occur due to (i) boundary layer flame propagation (critical velocity gradient), (ii) turbulent flame propagation in core flow, (iii) combustion instabilities, and (iv) upstream flame propagation induced by combustion induced vortex breakdown (CIVB). Flashback due to first two foregoing mechanisms is a topic of classical interest and has been studied extensively. Generally, analytical theories and experimental determinations of laminar and turbulent burning velocities model these mechanisms with sufficient precision for design usages. However, the swirling flow complicates the flashback processes in premixed combustions and the first two mechanisms inadequately describe the flashback propensity of most practical combustor designs. The presence of hydrogen in syngas significantly increases the potential for flashback. Due to high laminar burning velocity and low lean flammability limit, hydrogen tends to shift the combustor operating conditions towards flashback regime. Even a small amount of hydrogen in a fuel blend triggers the onset of flashback by altering the kinetics and thermophysical characteristics of the mixture. Additionally, the presence of hydrogen in the fuel mixture modifies the response of the flame to the global effects of stretch and preferential diffusion. Despite its immense importance in fuel flexible combustor design, little is known about the magnitude of fuel effects on CIVB induced flashback mechanism. Hence, this project investigates the effects of syngas compositions on flashback resulting from combustion induced vortex breakdown. The project uses controlled experiments and parametric modeling to understand the velocity field and flame interaction leading to CIVB driven flashback.

Ahsan Choudhuri

2011-03-31T23:59:59.000Z

338

VUV spectroscopy of water under cellular conditions  

Science Journals Connector (OSTI)

......Beer-Lambert calculation. RESULTS AND...is left in its electronic ground state...42 eV) and does not appear to...shift in the electronic state spectroscopy...films. In: Handbook of Surfaces and...study of the electronic state spectroscopy...gaseous water and does not show the......

R. Mota; R. Parafita; M. J. P. Maneira; N. J. Mason; G. Garcia; P. A. Ribeiro; M. Raposo; P. Limo-Vieira

2006-12-01T23:59:59.000Z

339

Gas-Phase Spectroscopy of Biomolecular  

E-Print Network [OSTI]

Gas-Phase Spectroscopy of Biomolecular Building Blocks Mattanjah S. de Vries1 and Pavel Hobza2 1, REMPI, computational chemistry, spectral hole burning, jet cooling Abstract Gas-phase spectroscopy lends. In recent years, we have seen enormous progress in the study of biomolecular building blocks in the gas

de Vries, Mattanjah S.

340

X-ray Spectroscopy of Cool Stars  

E-Print Network [OSTI]

High-resolution X-ray spectroscopy has addressed not only various topics in coronal physics of stars, but has also uncovered important features relevant for our understanding of stellar evolution and the stellar environment. I summarize recent progress in coronal X-ray spectroscopy and in particular also discuss new results from studies of X-rays from pre-main sequence stars.

M. Guedel

2006-09-11T23:59:59.000Z

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


341

Spectroscopy of 215Rn86  

SciTech Connect (OSTI)

The yrast level structure of 215,216Rn has been studied using in beam spectroscopy {alpha} - {gamma} - {gamma} coincidence techniques mainly through the 207Pb(18O, 2{alpha}2n) and 208Pb(18O, 2{alpha}2n) reactions in the 91-93 MeV energy range, using the 8{pi} GASP-ISIS spectrometer at Legnaro. The obtained low lying level scheme of 215Rn does not exhibit the alternating parity structure observed in their heavier known isotones 216Fr, 217Ra and 218Ac. The level scheme of 216Rn resulting from this study shows >From this result, the lightest nucleus showing evidence for reflection asymmetry is 216Fr defining one lowest-mass corner for this kind of phenomenon as N{>=}129 and Z{>=}87.

Debray, M. E. [Departamento de Fisica, Comision Nacional de Energia Atomica, 1429 Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad de San Martin, 1650 San Martin, Buenos Aires (Argentina); Davidson, M.; Davidson, J.; Hojman, D. [Departamento de Fisica, Comision Nacional de Energia Atomica, 1429 Buenos Aires (Argentina); CONICET, 1033 Buenos Aires (Argentina); Kreiner, A. J.; Cardona, M. A. [Departamento de Fisica, Comision Nacional de Energia Atomica, 1429 Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad de San Martin, 1650 San Martin, Buenos Aires (Argentina); CONICET, 1033 Buenos Aires (Argentina); Lenzi, S. [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Napoli, D. [Dipartimento di Fisica, Sezione di Padova, Padova (Italy)

2007-02-12T23:59:59.000Z

342

3D Spectroscopy and the Virtual Observatory  

E-Print Network [OSTI]

Integral field, or 3D, spectroscopy is the technique of obtaining spectral information over a two-dimensional, hopefully contiguous, field of view. While there is some form of astronomical 3D spectroscopy at all wavelengths, there has been a rapid increase in interest in optical and near-infrared 3D spectroscopy. This has resulted in the deployment of a large variety of integral-field spectrographs on most of the large optical/infrared telescopes. The amount of IFU data available in observatory archives is large and growing rapidly. The complications of treating IFU data as both imaging and spectroscopy make it a special challenge for the virtual observatory. This article describes the various techniques of optical and near-infrared spectroscopy and some of the general needs and issues related to the handling of 3D data by the virtual observatory.

Bryan W. Miller

2007-08-15T23:59:59.000Z

343

Optical breakdown threshold in nanosecond high repetition second harmonic generation by periodically poled Mg-doped LiTaO{sub 3} crystal  

SciTech Connect (OSTI)

Our study shows that a local temperature increase of ?1 K in the crystal lattice caused by second harmonic generation (SHG) and two-photon absorption of 532 nm radiation at the rear of periodically poled stoichiometric LiTaO{sub 3} crystal by changing spontaneous polarization induces a pyroelectric field ?10 kV/cm, accelerating free electrons to an energy of ?10 eV, followed by optical breakdown and crystal damage. Theoretical analysis leads to an explicit expression for the threshold laser fluence of optical breakdown giving ?1.2 J/cm{sup 2} for 1064 nm input radiation in 6.8 kHz pulsed SHG operation, agreeing well with the experimentally found value ?1.32 J/cm{sup 2}.

Louchev, Oleg A.; Wada, Satoshi [Center for Advanced Photonics, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)] [Center for Advanced Photonics, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Hatano, Hideki; Kitamura, Kenji [Division of Environment and Energy Materials, National Institute for Materials Science (NIMS) 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)] [Division of Environment and Energy Materials, National Institute for Materials Science (NIMS) 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

2013-08-26T23:59:59.000Z

344

Development of gas cluster ion beam surface treatments for reducing field emission and breakdown in RF cavities  

SciTech Connect (OSTI)

Sub-micron-scale surface roughness and contamination cause field emission that can lead to high voltage breakdown of electrodes, and these are limiting factors in the development of high gradient RF technology. We are studying various Gas Cluster Ion Beam (GCIB) treatments to smooth, clean, etch and/or chemically alter electrode surfaces to allow higher fields and accelerating gradients, and to reduce the time and cost of conditioning high voltage electrodes. For this paper, we have processed Nb, Stainless Steel, and Ti electrode materials using beams of Ar, O2, or NF3 +O2 clusters with accelerating potentials up to 35 kV. Using a Scanning Field Emission Microscope (SFEM), we have repeatedly seen a dramatic reduction in the number of field emission sites on Nb coupons treated with GCIB. Smoothing effects on Stainless steel and Ti substrates have been evaluated using AFM imaging and show that 200-nm wide polishing scratch marks are greatly attenuated. A 150-mm diameter GCIB treated stainless steel electrode has now shown virtually no DC field emission current at gradients over 20 MV/m.

D.R. Swenson; E. Degenkolb; A.T. Wu; Z. Insepov

2006-11-01T23:59:59.000Z

345

Silicon Photonics for chemical sensing and spectroscopy, diagnosis and therapy  

E-Print Network [OSTI]

5.5. Single-shot atomic absorption spectroscopy of rubidium26] time-wavelength atomic absorption spectroscopy of the D5.5. Single-shot atomic absorption spectroscopy of rubidium

Hon, Kam Yan

2012-01-01T23:59:59.000Z

346

X-ray Absorption Spectroscopy of Biologically Relevant Systems  

E-Print Network [OSTI]

308, Messer, B. M. X-ray Absorption Spectroscopy of AqueousSarcosine via X-ray Absorption Spectroscopy 5.1 Introductionwith Carboxylate by X-Ray Absorption Spectroscopy of Liquid

Uejio, Janel Sunayo

2010-01-01T23:59:59.000Z

347

Laser-induced nonresonant nuclear excitation in muonic atoms  

E-Print Network [OSTI]

Coherent nuclear excitation in strongly laser-driven muonic atoms is calculated. The nuclear transition is caused by the time-dependent Coulomb field of the oscillating charge density of the bound muon. A closed-form analytical expression for electric multipole transitions is derived and applied to various isotopes; the excitation probabilities are in general very small. We compare the process with other nuclear excitation mechanisms through coupling with atomic shells and discuss the prospects to observe it in experiment.

A. Shahbaz; C. Mller; T. J. Buervenich; C. H. Keitel

2008-12-13T23:59:59.000Z

348

Laser induced rotation of trapped chiral and achiral nematic droplets  

E-Print Network [OSTI]

We study the response of optically trapped achiral and chiralised nematic liquid crystal droplets to linear as well as circular polarised light. We find that there is internal dissipation in rotating achiral nematic droplets trapped in glycerine. We also demonstrate that some chiralised droplets rotate under linearly polarised light. The best fit to our data on chiralised droplets indicates that rotational frequency of these droplets with radius R is approximately proportional to1/R^2, rather than to 1/R^3.

Marjan Mosallaeipour; Yashodhan Hatwalne; N. V. Madhusudana; Sharath Ananthamurthy

2010-02-05T23:59:59.000Z

349

A Theory of Laser Induced Nuclear Reaction in Single Atoms  

SciTech Connect (OSTI)

An 'electron-bridge' mechanism of nuclear reaction in an atom or ion by ultra-intense laser fields is presented. A preliminary estimate of the intensity dependence of the rate of disintegration reaction of deuteron nucleus in deuterium atom is made for 800 nm laser fields. For intensities below 5x10{sup 21} W/cm{sup 2}, the rate of disintegration by the 'electron-bridge' mechanism is found to be small, but it rises sharply and becomes large already for {approx_equal}10{sup 22} W/cm{sup 2}.

Faisal, F. H. M.; Donner, C. [Fakultaet fuer Physik, Universitaet Bielefeld, Postfach 100131, D-33501 Bielefeld (Germany)

2010-02-02T23:59:59.000Z

350

COMPETING REACTION CHANNELS IN IR LASER INDUCED UNIMOLECULAR REACTIONS  

E-Print Network [OSTI]

M. R. Berman, P. B. Comita, C. B. Moore, and R. G. Bergman,of a collaboration with Paul Comita and Bob Bergman. ourused were prepared by Paul Comita. corporation in these

Berman, M.R.

2010-01-01T23:59:59.000Z

351

Laser-induced Damage in Optical Materials: 2004  

SciTech Connect (OSTI)

This volume contains papers presented at the 35th Annual Symposium on Optical Materials for High-Power Lasers, held at the National Institute of Standards and Technology in Boulder, Colorado, 22-24 September 2003. The symposium was attended by 125 participants from China, India, Russia, France, Germany, Japan, the United States, and the United Kingdom. A meeting summary and some 75 reviewed papers appear. The book is divided into sections devoted to the following topics: thin films, surfaces and mirrors, fundamental mechanisms, materials and measurements, and finally, understanding optical damage with ultrashort laser pulses. Topics of interest to the high-peak-power and high-average-power laser communities in addition to damage issues related to various research efforts and commercial laser applications are discussed. Also discussed are improved scaling relations as a function of pulse duration in the femtosecond range, beam footprint size, and irradiation of optical materials with wavelengths down to the x-ray region. New sources at shorter wavelengths continue to be developed, and a corresponding shift in emphasis to short-wavelength and repetitively pulsed damage problems can be seen in some of these papers. Fabrication and test procedures are discussed particularly in the area of thin films. New materials and the implication of defects on the damage process are emphasized in addition to new reports of conditioning effects and damage repair or damage mitigation.

Exarhos, Gregory J.; Guenther, Arthur H.; Kaiser, Norbert; Lewis, Keith L.; Soileau, M. J.; Stolz, Christopher J.

2005-03-01T23:59:59.000Z

352

Laser-induced spark ignition fundamental and applications  

Science Journals Connector (OSTI)

Laser ignition has become an active research topic in recent years because it has the potential to replace the conventional electric spark plugs in engines that are required to operate under much higher compression ratios, faster compression rates, and much leaner fuel-to-air ratios than gas engines today. It is anticipated that the igniter in these engines will face with pressures as high as 50MPa and temperatures as high as 4000K. Using the conventional ignition system, the required voltage and energy must be greatly increased (voltages in excess of 40kV) to reliably ignite the air and fuel mixture under these conditions. Increasing the voltage and energy does not always improve ignitability but it does create greater reliability problem. The objective of this paper is to review past work to identify some fundamental issues underlying the physics of the laser spark ignition process and research needs in order to bring the laser ignition concept into the realm of reality.

Tran X. Phuoc

2006-01-01T23:59:59.000Z

353

Dynamics of Laser Induced Transient Micro Bubble Clusters  

Science Journals Connector (OSTI)

Selective retina treatment (SRT) is a laser based therapy of retinal diseases associated with disorders of the retinal pigment epithelium (RPE) while preserving photoreceptors...

Fritz, Andreas; Ptaszynski, Lars; Stoehr, Hardo; Brinkmann, Ralf

354

Nuclear activation technique for analysis of laser induced energetic protons  

E-Print Network [OSTI]

. For that purpose, we have developed a method in which the particles induce nuclear reactions in a stack of copper for medical applications [6]). In addition, nuclear reaction yields and nuclear decay rates might be studied radioactive nuclei. In a stack of samples, each foil acts as a low energy proton filter for the following ones

Paris-Sud XI, Université de

355

DNA fragment sizing and sorting by laser-induced fluorescence  

DOE Patents [OSTI]

A method is provided for sizing DNA fragments using high speed detection systems, such as flow cytometry to determine unique characteristics of DNA pieces from a sample. In one characterization the DNA piece is fragmented at preselected sites to produce a plurality of DNA fragments. The DNA piece or the resulting DNA fragments are treated with a dye effective to stain stoichiometrically the DNA piece or the DNA fragments. The fluorescence from the dye in the stained fragments is then examined to generate an output functionally related to the number of nucleotides in each one of the DNA fragments. In one embodiment, the intensity of the fluorescence emissions from each fragment is linearly related to the fragment length. The distribution of DNA fragment sizes forms a characterization of the DNA piece for use in forensic and research applications.

Hammond, Mark L. (Angier, NC); Jett, James H. (Los Alamos, NM); Keller, Richard A. (Los Alamos, NM); Marrone, Babetta L. (Los Alamos, NM); Martin, John C. (Los Alamos, NM)

1996-01-01T23:59:59.000Z

356

In-situ Transmission Electron Microscopy and Spectroscopy Studies...  

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

Transmission Electron Microscopy and Spectroscopy Studies of Interfaces in Li-ion Batteries: Challenges and In-situ Transmission Electron Microscopy and Spectroscopy Studies of...

357

Self-corrected Sensors Based On Atomic Absorption Spectroscopy...  

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

corrected Sensors Based On Atomic Absorption Spectroscopy For Atom Flux Measurements In Molecular Beam Epitaxy. Self-corrected Sensors Based On Atomic Absorption Spectroscopy For...

358

Polarization-enhanced absorption spectroscopy for laser stabilization  

Science Journals Connector (OSTI)

We demonstrate a variation of pump-probe spectroscopy that is particularly useful for laser frequency stabilization. The polarization-enhanced absorption spectroscopy (POLEAS) signal...

Kunz, Paul D; Heavner, Thomas P; Jefferts, Steven R

2013-01-01T23:59:59.000Z

359

Operando Raman and Theoretical Vibration Spectroscopy of Non...  

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

Operando Raman and Theoretical Vibration Spectroscopy of Non-PGM Catalysts Operando Raman and Theoretical Vibration Spectroscopy of Non-PGM Catalysts Presentation about...

360

High Resolution and Low-Temperature Photoelectron Spectroscopy...  

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

High Resolution and Low-Temperature Photoelectron Spectroscopy of an Oxygen-Linked Fullerene Dimer Dianion: C120O2-. High Resolution and Low-Temperature Photoelectron Spectroscopy...

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


361

Infrared near-field spectroscopy of trace explosives using an...  

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

spectroscopy of trace explosives using an external cavity quantum cascade laser. Infrared near-field spectroscopy of trace explosives using an external cavity quantum...

362

Infrared Spectroscopy and Optical Constants of Porous Amorphous...  

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

Spectroscopy and Optical Constants of Porous Amorphous Solid Water. Infrared Spectroscopy and Optical Constants of Porous Amorphous Solid Water. Abstract: Reflection-absorption...

363

Laser photoelectron spectroscopy of ions  

SciTech Connect (OSTI)

This enterprise uses photoelectron spectroscopy to study the properties of negative ions and radicals. The essence of our experiment is to cross a 0.6 keV mass-selected ion beam (M{sup {minus}}) with the output of a CW laser, {Dirac h}{omega}{sub o}. The resultant detached photoelectrons with kinetic energy, KE, are energy analyzed by means of a set of electrostatic hemispherical analyzers. Analysis of the photoelectron spectra enables us to extract molecular electron affinities, vibrational frequencies and electronic splittings of the final radical, M, as well as the relative molecular geometries of ions (M{sup {minus}}) and radicals (M). We have scrutinized the two simplest nitrenes: methylnitrene (CH{sub 3}N) and phenylnitrene (C{sub 6}H{sub 5}N). By preparing the corresponding anions, CH{sub 3}N{sup {minus}} and C{sub 6}H{sub 5}N{sup {minus}}, we have studied these nitrene biradicals. Singlet methylnitrene is especially interesting since it is formally a transition state.''

Ellison, G.B.

1992-01-16T23:59:59.000Z

364

PAC spectroscopy of electronic ceramics  

SciTech Connect (OSTI)

Dilute indium dopants in cerium oxides and YBa{sub 2}Cu{sub 3}O{sub x} have been studied by{sup 111}In/Cd Perturbed Angular Correlation (PAC) spectroscopy. By controlling oxygen vacancy concentration in the cerium oxides through doping or high-temperature vacuum annealing, we have found that indium always forms a defect complex unless the sample is doped to reduce greatly the oxygen vacancy concentration. Three different vacancy-associated complexes are found with concentrations that depend on doping and oxygen stoichiometry. Another defect complex occurs in samples having negligible vacancy concentration. At low temperatures, evidence is found of interaction with an electronic hole trapped by {sup 111}Cd after the radioactive decay of the {sup 111}In parent. In YBa{sub 2}Cu{sub 3}O{sub x} the indium substitutes preferentially at the Y site but has measurable probability of substitution in at least one of the two copper sites. A symmetry change near 650 {degree}C is consistent with the well-documented orthorhombic/tetragonal transition for samples in air or oxygen.

Gardner, J.A.; Wang, Ruiping; Schwenker, R. [Oregon Univ., Eugene, OR (United States). Dept. of Physics; Evenson, W.E. [Brigham Young Univ., Provo, UT (United States). Dept. of Physics and Astronomy; Rasera, R.L. [Maryland Univ., Catonsville, MD (United States). Dept. of Physics; Sommers, J.A. [Teledyne-Wah Chang, Albany, OR (United States)

1991-12-31T23:59:59.000Z

365

PAC spectroscopy of electronic ceramics  

SciTech Connect (OSTI)

Dilute indium dopants in cerium oxides and YBa{sub 2}Cu{sub 3}O{sub x} have been studied by{sup 111}In/Cd Perturbed Angular Correlation (PAC) spectroscopy. By controlling oxygen vacancy concentration in the cerium oxides through doping or high-temperature vacuum annealing, we have found that indium always forms a defect complex unless the sample is doped to reduce greatly the oxygen vacancy concentration. Three different vacancy-associated complexes are found with concentrations that depend on doping and oxygen stoichiometry. Another defect complex occurs in samples having negligible vacancy concentration. At low temperatures, evidence is found of interaction with an electronic hole trapped by {sup 111}Cd after the radioactive decay of the {sup 111}In parent. In YBa{sub 2}Cu{sub 3}O{sub x} the indium substitutes preferentially at the Y site but has measurable probability of substitution in at least one of the two copper sites. A symmetry change near 650 {degree}C is consistent with the well-documented orthorhombic/tetragonal transition for samples in air or oxygen.

Gardner, J.A.; Wang, Ruiping; Schwenker, R. (Oregon Univ., Eugene, OR (United States). Dept. of Physics); Evenson, W.E. (Brigham Young Univ., Provo, UT (United States). Dept. of Physics and Astronomy); Rasera, R.L. (Maryland Univ., Catonsville, MD (United States). Dept. of Physics); Sommers, J.A. (Teledyne-Wah Chang, Albany, OR (United States))

1991-01-01T23:59:59.000Z

366

INSTRUMENTATION FOR FAR INFRARED SPECTROSCOPY.  

SciTech Connect (OSTI)

Fourier transform spectrometers developed in three distinct spectral regions in the early 1960s. Pierre Connes and his coworkers in France developed remarkably sophisticated step-scan interferometers that permitted near-infrared spectra to be measured with a resolution of better than 0.0 1 cm{sup {minus}1}. These instruments may be considered the forerunners of the step-scan interferometers made by Bruker, Bio-Rad (Cambridge, MA, USA) and Nicolet although their principal application was in the field of astronomy. Low-resolution rapid-scanning interferometers were developed by Larry Mertz and his colleagues at Block Engineering (Cambridge, MA, USA) for remote sensing. Nonetheless, the FT-IR spectrometers that are so prevalent in chemical laboratories today are direct descendants of these instruments. The interferometers that were developed for far-infrared spectrometry in Gebbie's laboratory ,have had no commercial counterparts for at least 15 years. However, it could be argued that these instruments did as much to demonstrate the power of Fourier transform spectroscopy to the chemical community as any of the instruments developed for mid- and near-infrared spectrometry. Their performance was every bit as good as today's rapid-scanning interferometers. However, the market for these instruments is so small today that it has proved more lucrative to modify rapid-scanning interferometers that were originally designed for mid-infrared spectrometry than to compete with these instruments with slow continuous scan or step-scan interferometers.

GRIFFITHS, P.R.; HOMES, C.

2001-05-04T23:59:59.000Z

367

2512 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 36, NO. 5, OCTOBER 2008 Experimental Investigation of 193-nm  

E-Print Network [OSTI]

-initiated electron cascading plasma process begins when a pulsed laser beam is focused down to a small spatial domain of 193-nm Laser Breakdown in Air Magesh Thiyagarajan, Member, IEEE, and John E. Scharer, Senior Member, IEEE Abstract--We present the measurements and analysis of laser- induced breakdown processes in dry

Scharer, John E.

368

Soft X-Ray and Vacuum Ultraviolet Based Spectroscopy of the Actinides  

SciTech Connect (OSTI)

The subjects of discussion included: VUV photoelectron spectroscopy, X-ray photoelectron spectroscopy, Synchrotron-radiation-based photoelectron spectroscopy, Soft x-ray absorption spectroscopy, Soft x-ray emission spectroscopy, Inverse photoelectron spectroscopy, Bremstrahlung Isochromat Spectroscopy, Low energy IPES, Resonant inverse photoelectron spectroscopy.

Tobin, J G

2011-03-17T23:59:59.000Z

369

Instrument Series: Spectroscopy and Diffraction XPS Imaging  

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

XPS Imaging XPS Imaging The X-ray photoelectron spectroscopy (XPS) imaging system provides fast, quantitative, real-time parallel imaging with highest resolution spectroscopy at all analysis areas. In addition, the system is equipped with temperature programmed desorption (TPD), ultraviolet photoelectron spectroscopy (UPS), ion scattering spectroscopy (ISS), a cluster/Ar + ion gun, and a five-axis automated stage with variable temperature sample environment at the analysis chamber. The system is also integrated with a radial distribution chamber (RDC), a full-size glove box, and a cold-stage at the sample introduction for air-sensitive, liquid-semisolid, biological and environmental sample transfers. In addition, the RDC has a simple sample transfer mechanism to the

370

Quantitative Elemental Analyses by Plasma Emission Spectroscopy  

Science Journals Connector (OSTI)

...Elemental Analyses by Plasma Emission Spectroscopy...Argon-supported inductively coupled plasmas operated at atmospheric pressures are excellent...HIGH-FREQUENCY ARGON PLASMA FOR OPTICAL EMISSION...EXPERIMENTAL-STUDY OF A 1-KW, 50-MHZ RF INDUCTIVELY COUPLED...

Velmer A. Fassel

1978-10-13T23:59:59.000Z

371

Developments and advances in nonlinear terahertz spectroscopy  

E-Print Network [OSTI]

Nonlinear terahertz (THz) spectroscopy is a rapidly developing field, which is concerned with driving and observing nonlinear material responses in the THz range of the electromagnetic spectrum. In this thesis, I present ...

Brandt, Nathaniel Curran

2014-01-01T23:59:59.000Z

372

Metamaterial-Enhanced Nonlinear Terahertz Spectroscopy  

E-Print Network [OSTI]

We demonstrate large nonlinear terahertz responses in the gaps of metamaterial split ring resonators in several materials and use nonlinear THz transmission and THz-pump/THz-probe spectroscopy to study the nonlinear responses ...

Hwang, Harold Young

373

Quantitative Elemental Analyses by Plasma Emission Spectroscopy  

Science Journals Connector (OSTI)

...Elemental Analyses by Plasma Emission Spectroscopy...inductively coupled plasmas operated at atmospheric...INDUCTIVELY-COUPLED HIGH-FREQUENCY ARGON PLASMA FOR OPTICAL EMISSION...1-KW, 50-MHZ RF INDUCTIVELY COUPLED...STUDIES OF A RADIO-FREQUENCY INDUCTIVELY COUPLED...

Velmer A. Fassel

1978-10-13T23:59:59.000Z

374

Microfluidic devices for terahertz spectroscopy of biomolecules  

E-Print Network [OSTI]

, J. Hesler, and A.C. Samuels, "THz-spectroscopy of biological molecules," J. Bio. Phys. 29, 89/water systems by compact sensor chips," Appl. Phys. Lett. 89, 041114 (2006). 10. T. Baras, T. Kleine

Afshari, Ehsan

375

Applying near-infrared spectroscopy (nirs)  

E-Print Network [OSTI]

investigated. A recently developed optical imaging technique called near-infrared spectroscopy (NIRS) shows promise for being an acceptable alternative to invasive imaging techniques. NIRS measures correlates of neural activity by assessing hemoglobin...

Wruck, Eric Michael

2005-08-29T23:59:59.000Z

376

Theory and Applications of NMR Spectroscopy Arthur S. Edison  

E-Print Network [OSTI]

constructed from combinations of: "Protein NMR spectroscopy: Principles and Practice" Cavanagh, Fairbrother

Collins, Gary S.

377

Publications  

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

7 results: 7 results: BibTex RIS RTF XML Sort by: Author Title Type [ Year (Desc) ] Filters: Author is Costas P. Grigoropoulos [Clear All Filters] 2010 Owens, Travis, Samuel S. Mao, Erin K. Canfield, Costas P. Grigoropoulos, Xianglei Mao, and Richard E. Russo. "Ultrafast thin-film laser-induced breakdown spectroscopy of doped oxides." Applied Optics 49 (2010): C67-C69. Barcelo, Steven J., Matthew Rogers, Costas P. Grigoropoulos, and Samuel S. Mao. "Hydrogen Storage property of sandwiched magnesium hydride naoparticle thin film." International Journal of Hydrogen Energy (2010). 2009 Rogers, Matthew, Steven J. Barcelo, Xiaobo Chen, Thomas J. Richardson, Vincent Berube, Gang Chen, Mildred S. Dresselhaus, Costas P. Grigoropoulos, and Samuel S. Mao. "Hydrogen Storage Characteristics of Nanograined

378

Bipin Bihari resume  

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

Bipin Bihari Bipin Bihari Argonne National Laboratory Energy Systems Division 9700 South Cass Avenue, Building 362 Argonne, IL 60439 phone: 630/252-6492, fax: 630/252-3443 e-mail: bihari@anl.gov Professional Experience  2004-Present. Argonne National Laboratory o Designing fiber optic laser delivery for a laser based ignition application in a large bore multi-cylinder reciprocation natural gas engine o Developing optical diagnostics techniques for natural gas engines o Using laser induced breakdown spectroscopy as a diagnostic tool in engines  1997-2003. Sr. Scientist/Small Business Innovation Research (SBIR) Program manager, Omega Optics, Inc./Radiant Photonics, Austin, Texas/ Microelectronics Research Center, University of Texas-Austin, Texas

379

U  

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

4, 2008 4, 2008 Dustin McIntyre, a mechanical engineer at the U.S. Department of Energy's National Energy Technology Laboratory (NETL), is one of the inventors of a laser spark distribution and ignition system developed at NETL which has recently been issued a patent. f al electrical spark plugs. McIntyre, a resident of Morgantown, WV, received his BS degrees in electrical engineering and computer engineering and MS and PhD in mechanical engineering from West Virginia University in Morgantown, WV. Producing a high peak power laser spark from a single low power pulse, this laser spark distribution and ignition system has application in natural gas-fueled reciprocating engines, turbine combustors, explosives, and laser- induced breakdown spectroscopy diagnostic sensors. The laser spark plug

380

Microsoft PowerPoint - Hanson_LIBS_IPRC  

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

Effect Effect of Temperature Variation on LIBS Spectra of Molten Salts Cynthia Hanson and Supathorn Phongikaroon Nuclear Engineering Program, University of Idaho Jeremy J. Hatch and Jill R. Scott Interfacial Chemistry, Idaho National Laboratory International Pyroprocessing Research Conference 2012 8-29-12 Agenda * Mark-IV Electrorefiner * Motivation * Overview of LIBS (Laser-induced Breakdown Spectroscopy) * Project Objective * Experimental Set-up and Method Development * Results * Summary and Future Work 2 Mark-IV Electrorefiner * Processes used nuclear fuel (UNF) * Uranium from UNF is electrochemically transferred through the salt forming deposits on the cathode * Build up of fission products, transuranics, etc. inhibits efficiency and creates liabilities 3 Challenge for in-situ Electrorefiner Analysis 4 * No current method for real time analysis of salt * 500 C operating

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


381

Development of Real-Time Coal Monitoring Instrument  

SciTech Connect (OSTI)

Relying on coal for energy requires optimizing the extraction of heat content from various blends of coal fuel and reducing harmful constituents and byproducts. Having a real-time measurement instrument provides relevant information about toxic constituents released in the atmosphere from burning coal and optimizes the performance of a power plant. A few commercial instruments exist and have been in operation for more than a decade. However, most of these instruments are based on radioactive sources and are bulky, expensive and time-consuming. The proposed instrument is based on the Laser Induced Breakdown Spectroscopy (LIBS). The advantage of LIBS is that it is a standoff instrument, does not require sample preparation and provides precise information about sample constituents.

Rajan Gurjar, Ph.D.

2010-06-17T23:59:59.000Z

382

Laser Spark Distribution and Ignition System  

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

Spark Distribution and Ignition System Spark Distribution and Ignition System Opportunity The Department of Energy's National Energy Technology Laboratory (NETL) is seeking licensing partners interested in implement- ing United States Patent Number 7,421,166 entitled "Laser Spark Distribution and Ignition System." Disclosed in this patent is NETL's laser spark distribution and ignition system, which reduces the high-power optical requirements normally needed for such a system by using optical fibers to deliver low-peak-energy pumping pulses to a laser amplifier or laser oscillator. Laser spark generators then produce a high-peak-power laser spark from a single low power pulse. The system has ap- plications in natural gas fueled reciprocating engines, turbine combustors, explosives, and laser induced breakdown spectroscopy diagnostic sensors.

383

Ultrafast Spectroscopy of Warm Dense Matter  

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

Ultrafast Spectroscopy of Warm Dense Matter Print Ultrafast Spectroscopy of Warm Dense Matter Print Being neither solid, liquid, gas, nor plasma, warm dense matter (WDM) occupies a no man's land in the map of material phases. Its temperature can range between that of planetary cores (tens of thousands K) to that of stellar cores (hundreds of thousands K). Not only is it prevalent throughout the universe, it is relevant to inertial confinement fusion (ICF) and material performance under extreme conditions. However, because of its extreme temperatures and pressures, WDM tends to be drastically transient and thus difficult to study in the laboratory. Now, researchers have set up ultrafast x-ray absorption spectroscopy at the ALS to measure the electronic structure of WDMs, demonstrating that fast-changing electron temperatures of matter under extreme conditions can be determined with picosecond resolution.

384

Spectroscopy and atomic force microscopy of biomass  

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

Spectroscopy Spectroscopy and atomic force microscopy of biomass L. Tetard a,b , A. Passian a,b,n , R.H. Farahi a , U.C. Kalluri c , B.H. Davison c , T. Thundat a,b a Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA b Department of Physics, University of Tennessee, Knoxville, TN 37996, USA c Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA a r t i c l e i n f o Keywords: Atomic force microscopy Spectroscopy Plant cells Biomass Nanomechanics a b s t r a c t Scanning probe microscopy has emerged as a powerful approach to a broader understanding of the molecular architecture of cell walls, which may shed light on the challenge of efficient cellulosic ethanol production. We have obtained preliminary images of both Populus and switchgrass samples using atomic force microscopy (AFM). The results show distinctive features that are shared by switchgrass

385

Spectroscopy of element 115 decay chains  

SciTech Connect (OSTI)

A high-resolution a, X-ray and -ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum fu r Schwerionenforschung. Thirty correlated a-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z = 115. The data includes first candidates of fingerprinting the decay step Mt --> Bh with characteristic X rays. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z > 112. Comprehensive Monte-Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.

Rudolph, Dirk [Lund University, Sweden; Forsberg, U. [Lund University, Sweden; Golubev, P. [Lund University, Sweden; Sarmiento, L. G. [Lund University, Sweden; Yakushev, A. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Andersson, L.-L. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Di Nitto, A. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Duehllmann, Ch. E. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Gates, J. M. [Lawrence Berkeley National Laboratory (LBNL); Gregorich, K. E. [Lawrence Berkeley National Laboratory (LBNL); Gross, Carl J [ORNL; Hessberger, F. P. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Herzberg, R.-D [University of Liverpool; Khuyagbaatar, J. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Kratz, J. V. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Rykaczewski, Krzysztof Piotr [ORNL; Schaedel, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Aberg, S. [Lund University, Sweden; Ackermann, D. [GSI-Hemholtzzentrum fur Schwerionenforschung, Darmstadt, Germany; Block, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Brand, H. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Carlsson, B. G. [Lund University, Sweden; Cox, D. [University of Liverpool; Derkx, X. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Eberhardt, K. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Even, J. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Fahlander, C. [Lund University, Sweden; Gerl, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Jaeger, E. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kindler, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Krier, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kojouharov, I. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kurz, N. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Lommel, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Mistry, A. [University of Liverpool; Mokry, C. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Nitsche, H. [Lawrence Berkeley National Laboratory (LBNL); Omtvedt, J. P. [Paul Scherrer Institut, Villigen, Switzerland; Papadakis, P. [University of Liverpool; Ragnarsson, I. [Lund University, Sweden; Runke, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Schaffner, H. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Schausten, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Thoerle-Pospiech, P. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Torres, T. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Traut, T. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Trautmann, N. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Tuerler, A. [Paul Scherrer Institut, Villigen, Switzerland; Ward, A. [University of Liverpool; Ward, D. E. [Lund University, Sweden; Wiehl, N. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany

2013-01-01T23:59:59.000Z

386

Study of the dielectric breakdown properties of hot SF{sub 6}CF{sub 4} mixtures at 0.011.6 MPa  

SciTech Connect (OSTI)

The dielectric breakdown properties of SF{sub 6}CF{sub 4} mixtures were investigated at different ratios of SF{sub 6}, 0.011.6 MPa, and gas temperatures up to 3000 K. Initially, the equilibrium compositions of SF{sub 6}CF{sub 4} mixtures were calculated by minimizing the Gibbs free energy under the assumptions of local thermodynamic and chemical equilibrium. Then the electron energy distribution function was obtained based on those data by solving the Boltzmann equation under the zero-dimensional two-term spherical harmonic approximation. Finally, the critical reduced electric field strength (E/N){sub cr} of SF{sub 6}CF{sub 4} mixtures, which is defined as the value for which total ionization reaction is equal to total attachment reaction, were determined and analyzed. The results confirm the superior breakdown properties of pure SF{sub 6} at relatively low gas temperatures. However, for higher gas temperatures (i.e., T > 2200 K at 0.4 MPa), the (E/N){sub cr} in SF{sub 6}CF{sub 4} mixtures are obviously higher than that in pure SF{sub 6} and the values of (E/N){sub cr} increase with the reduction of the ratio of SF{sub 6}.

Li, Xingwen; Zhao, Hu; Jia, Shenli [State Key Laboratory of Electrical Insulation and Power Equipment, Xian Jiaotong University, No. 28 XianNing West Road, Xian, Shaanxi Province 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xian Jiaotong University, No. 28 XianNing West Road, Xian, Shaanxi Province 710049 (China); Murphy, Anthony B. [CSIRO Materials Science and Engineering, PO Box 218, Lindfield, NSW 2070 (Australia)] [CSIRO Materials Science and Engineering, PO Box 218, Lindfield, NSW 2070 (Australia)

2013-08-07T23:59:59.000Z

387

SPECIES DETERMINATION OF ORGANOMETALLIC COMPOUNDS USING ZEEMAN ATOMIC ABSORPTION SPECTROSCOPY WITH LIQUID CHROMATOGRAPHY  

E-Print Network [OSTI]

Compounds Using Zeeman Atomic Absorption Spectroscopy WithCompounds Using Zeeman ,Atomic Absorption Spectroscopy withcapabilities of Zeeman atomic absorption spectroscopy (ZAA)

Koizumi, H.

2011-01-01T23:59:59.000Z

388

X-RAY ABSORPTION SPECTROSCOPY FOR THE CHEMICAL CHARACTERIZATION OF ATMOSPHERIC AEROSOLS  

E-Print Network [OSTI]

November 11-16 9 1979 X-RAY ABSORPTION SPECTROSCOPY FOR THEUniversity of California. ABSORPTION SPECTROSCOPY FOR THEand x-ray emission and absorption spectroscopy. The first

Jaklevic, J. M.

2011-01-01T23:59:59.000Z

389

A New Spin on Photoemission Spectroscopy  

SciTech Connect (OSTI)

The electronic spin degree of freedom is of general fundamental importance to all matter. Understanding its complex roles and behavior in the solid state, particularly in highly correlated and magnetic materials, has grown increasingly desirable as technology demands advanced devices and materials based on ever stricter comprehension and control of the electron spin. However, direct and efficient spin dependent probes of electronic structure are currently lacking. Angle Resolved Photoemission Spectroscopy (ARPES) has become one of the most successful experimental tools for elucidating solid state electronic structures, bolstered bycontinual breakthroughs in efficient instrumentation. In contrast, spin-resolved photoemission spectroscopy has lagged behind due to a lack of similar instrumental advances. The power of photoemission spectroscopy and the pertinence of electronic spin in the current research climate combine to make breakthroughs in Spin and Angle Resolved Photoemission Spectroscopy (SARPES) a high priority . This thesis details the development of a unique instrument for efficient SARPES and represents a radical departure from conventional methods. A custom designed spin polarimeter based on low energy exchange scattering is developed, with projected efficiency gains of two orders of magnitude over current state-of-the-art polarimeters. For energy analysis, the popular hemispherical analyzer is eschewed for a custom Time-of-Flight (TOF) analyzer offering an additional order of magnitude gain in efficiency. The combined instrument signifies the breakthrough needed to perform the high resolution SARPES experiments necessary for untangling the complex spin-dependent electronic structures central to today?s condensed matter physics.

Advanced Light Source; Jozwiak, Chris

2008-12-18T23:59:59.000Z

390

Laser spectroscopy and dynamics of transient species  

SciTech Connect (OSTI)

The goal of this program is to study the vibrational and electronic spectra and excited state dynamics of a number of transient sulfur and oxygen species. A variety of supersonic jet techniques, as well as high resolution FT-IR and intracavity dye laser spectroscopy, have been applied to these studies.

Clouthier, D.J. [Univ. of Kentucky, Lexington (United States)

1993-12-01T23:59:59.000Z

391

Nanoscale Spectroscopy and Nanotechnology 8 Scientific Program  

E-Print Network [OSTI]

1 Nanoscale Spectroscopy and Nanotechnology 8 Scientific Program Gleacher Center Chicago, USA #12 Materials, Argonne National Laboratory, Department of Medicine, The University of Chicago USA. (Invited, and Dept. of Medicine, University of Illinois, Chicago, USA. Fabrication and characterization of smart CNT

Kemner, Ken

392

Multichannel photodiode detector for ultrafast optical spectroscopy  

E-Print Network [OSTI]

Construction and characterization of a multichannel photodiode detector based on commercially available components with high signal to noise of $\\sim10^{6}$ and a rapid frame rate, suitable for time resolved femtosecond spectroscopy with high repetition femtosecond sources, is presented.

Mertelj, T; Borzda, T; Vaskivskyi, I; Pogrebna, A; Mihailovic, D

2014-01-01T23:59:59.000Z

393

Beam-Foil Spectroscopy - Quo Vadis?  

SciTech Connect (OSTI)

Beam-foil spectroscopy after 45 years: what has been realized of the promises, what is the state of the art, what is the status of the field, what present atomic physics problems should the technique be applied to, where can it be done? Will it be done? Beam-foil spectroscopy and its sibling techniques have been outstandingly productive tools of atomic physics, providing both important data and insight. For some forty years, the developments have led to improvements in working range and reliability, and catalogues of desirable further measurements can be formulated. However, most of the key persons who have carried out and directed much of the development effort are nearing retirement, and with them the leading facilities. it is thus not likely that many of the desirable BFS projects discussed will presently be pursued. High-Z element, high-charge state spectroscopy and some specific long-lived level lifetime measurements will, however, be taken over by electron beam ion traps, and heavy-ion storage rings will contribute some important benchmark measurements on electric-dipole forbidden or hyperfine-induced transitions. Beam-foil spectroscopy can still be expected to solve a number of interesting atomic physics questions, but as a technique, at present, it has dropped from fashion and support.

Trabert, E

2008-05-26T23:59:59.000Z

394

Spectroscopy and decays of charm and bottom  

SciTech Connect (OSTI)

After a brief review of the quark model, we discuss our present knowledge of the spectroscopy of charm and bottom mesons and baryons. We go on to review the lifetimes, semileptonic, and purely leptonic decays of these particles. We conclude with a brief discussion B and D mixing and rare decays.

Butler, J.N.

1997-10-01T23:59:59.000Z

395

Single molecule spectroscopy of tetrahedral oligophenylenevinylene molecules  

E-Print Network [OSTI]

Single molecule spectroscopy of tetrahedral oligophenylenevinylene molecules Melissa A. Summers form 17 July 2002 Abstract We probe the fluorescence from single molecules of a new class molecules and compare these signals with the fluorescence from single arm molecules. Our results show

Buratto, Steve

396

Multivariate Optical Computation for Predictive Spectroscopy  

E-Print Network [OSTI]

Multivariate Optical Computation for Predictive Spectroscopy Matthew P. Nelson, Jeffrey F. Aust, J Research Council of Canada, Ottawa, Ontario, Canada K1A 0R6 A novel optical approach to predicting chemical into the structure of a set of paired optical filters. Light passing through the paired filters produces an analog

Myrick, Michael Lenn

397

Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy  

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

Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Wednesday, 29 October 2008 00:00 Graphene-a single layer...

398

Depth-resolved cathodoluminescence spectroscopy of silicon supersaturated with sulfur  

E-Print Network [OSTI]

We investigate the luminescence of Si supersaturated with S (Si:S) using depth-resolved cathodoluminescence spectroscopy and secondary ion mass spectroscopy as the S concentration is varied over 2 orders of magnitude ...

Fabbri, Filippo

399

Single-molecule reactions and spectroscopy via vibrational excitation  

Science Journals Connector (OSTI)

...J. Kelly and R. E. Palmer Single-molecule reactions and spectroscopy via...Inelastic Tunnelling|Vibration|Single Molecule|Scanning Tunnelling Microscopy (Stm)| Single-molecule reactions and spectroscopy via...

2004-01-01T23:59:59.000Z

400

X-Ray Photoelectron Spectroscopy (XPS) Applied to Soot & What...  

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

Photoelectron Spectroscopy (XPS) Applied to Soot & What It Can Do for You X-Ray Photoelectron Spectroscopy (XPS) Applied to Soot & What It Can Do for You Presentation given at DEER...

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


401

Core-level Spectroscopies with FEFF9 and OCEAN  

E-Print Network [OSTI]

Core-level Spectroscopies with FEFF9 and OCEAN J. J. Rehr1,4 K. Gilmore,2,4 J. Kas,1 J. Vinson,3 E European Theoretical Spectroscopy Facility Supported by DOE BES Soleil Theory Day Synchrotron SOLEIL, Grand Amphi 6/5/2014 #12;Core-level Spectroscopies with FEFF9 and OCEAN · GOAL: ab initio theory · Accuracy

Botti, Silvana

402

E-Print Network 3.0 - absorption spectroscopy measurements Sample...  

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

A partial sampling of these techniques includes: Absorption spectroscopy Atomic absorption... spectroscopy Auger electron ... Source: Yucca Mountain Project, US...

403

E-Print Network 3.0 - atomic spectroscopy study Sample Search...  

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

A partial sampling of these techniques includes: Absorption spectroscopy Atomic absorption... spectroscopy Atomic emission ... Source: Yucca Mountain Project,...

404

Work Breakdown Structure and Plant/Equipment Designation System Numbering Scheme for the High Temperature Gas- Cooled Reactor (HTGR) Component Test Capability (CTC)  

SciTech Connect (OSTI)

This white paper investigates the potential integration of the CTC work breakdown structure numbering scheme with a plant/equipment numbering system (PNS), or alternatively referred to in industry as a reference designation system (RDS). Ideally, the goal of such integration would be a single, common referencing system for the life cycle of the CTC that supports all the various processes (e.g., information, execution, and control) that necessitate plant and equipment numbers be assigned. This white paper focuses on discovering the full scope of Idaho National Laboratory (INL) processes to which this goal might be applied as well as the factors likely to affect decisions about implementation. Later, a procedure for assigning these numbers will be developed using this white paper as a starting point and that reflects the resolved scope and outcome of associated decisions.

Jeffrey D Bryan

2009-09-01T23:59:59.000Z

405

Charge exchange recombination spectroscopy on fusion devices  

SciTech Connect (OSTI)

For fusion, obtaining reliable measurements of basic plasma parameters like ion and electron densities and temperatures is a primary goal. For theory, measurements are needed as a function of time and space to understand plasma transport and confinement with the ultimate goal of achieving economic nuclear fusion power. Electron profile measurements and plasma spectroscopy for the plasma ions are introduced. With the advent of Neutral Beam auxiliary plasma heating, Charge Exchange Recombination Spectroscopy provides accurate and time resolved measurements of the ions in large volume fusion devices. In acknowledgement of Nicol Peacock's role in the development of these techniques, still at the forefront of plasma fusion research, this paper describes the evolution of this diagnostic method.

Duval, B. P. [Centre de Recherches en Physique des Plasmas, EPFL, Lausanne (Switzerland)

2012-05-25T23:59:59.000Z

406

Raman spectroscopy study of selected uranophanes  

Science Journals Connector (OSTI)

Raman spectra at 298 and 77K of three uranophane samples from different localities are described and interpreted. The spectra are sample dependent. UO bond lengths in uranyls are calculated from the spectra and compared with the published data of single crystal structure and EXAFS spectroscopy. Hydrogen-bonding of water molecules and silanols is discussed and the proton mobility in uranophane sheet crystal structure is assumed.

Ray L. Frost; Ji? ?ejka; Matt L. Weier; Wayde N. Martens

2006-01-01T23:59:59.000Z

407

Dielectric breakdown properties of hot SF{sub 6}-CO{sub 2} mixtures at temperatures of 3003500?K and pressures of 0.011.0?MPa  

SciTech Connect (OSTI)

Recently, much attention has been paid to SF{sub 6}-CO{sub 2} mixtures as one of substitutes for pure SF{sub 6} gas. In this paper, the dielectric breakdown properties of hot SF{sub 6}-CO{sub 2} mixtures are investigated at temperatures of 3003500?K and pressures of 0.011.0?MPa. Under the assumptions of local thermodynamic equilibrium and local chemical equilibrium, the equilibrium compositions of hot SF{sub 6}-CO{sub 2} mixtures with different CO{sub 2} proportions are obtained based on Gibbs free energy minimization. The cross sections for interactions between electrons and neutral species are presented. Some unknown ionization cross sections are determined theoretically using DeutschMrk (DM) formalism based on quantum chemistry. Two-term Boltzmann equation is adopted to calculate the electron energy distribution function, reduced ionization coefficient, reduced attachment coefficient, and reduced effective ionization coefficient. Then the reduced critical electric field strength of mixtures, corresponding to dielectric breakdown performances, is determined when the generation and loss of electrons are balanced. Finally, the influences of temperature, pressure, and CO{sub 2} proportion on the reduced critical electric field strength are studied. It is found that a large percentage of CO{sub 2} can obviously reduce concentrations of high-energy electrons. At temperatures above 1750?K, an addition of CO{sub 2} to SF{sub 6} gas can enhance dielectric breakdown performances. However, at low temperatures, too much CO{sub 2} added into mixtures can reduce dielectric breakdown abilities. In addition, increasing gas pressure can improve dielectric breakdown performances. But the influence will be no more significant if pressure is over 0.8?MPa.

Zhong, Linlin; Yang, Aijun; Wang, Xiaohua, E-mail: xhw@mail.xjtu.edu.cn; Liu, Dingxin; Wu, Yi; Rong, Mingzhe, E-mail: mzrong@mail.xjtu.edu.cn [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049 (China)

2014-05-15T23:59:59.000Z

408

Estimating radiological background using imaging spectroscopy  

SciTech Connect (OSTI)

Optical imaging spectroscopy is investigated as a method to estimate radiological background by spectral identification of soils, sediments, rocks, minerals and building materials derived from natural materials and assigning tabulated radiological emission values to these materials. Radiological airborne surveys are undertaken by local, state and federal agencies to identify the presence of radiological materials out of regulatory compliance. Detection performance in such surveys is determined by (among other factors) the uncertainty in the radiation background; increased knowledge of the expected radiation background will improve the ability to detect low-activity radiological materials. Radiological background due to naturally occurring radiological materials (NORM) can be estimated by reference to previous survey results, use of global 40K, 238U, and 232Th (KUT) values, reference to existing USGS radiation background maps, or by a moving average of the data as it is acquired. Each of these methods has its drawbacks: previous survey results may not include recent changes, the global average provides only a zero-order estimate, the USGS background radiation map resolutions are coarse and are accurate only to 1 km 25 km sampling intervals depending on locale, and a moving average may essentially low pass filter the data to obscure small changes in radiation counts. Imaging spectroscopy from airborne or spaceborne platforms can offer higher resolution identification of materials and background, as well as provide imaging context information. AVIRIS hyperspectral image data is analyzed using commercial exploitation software to determine the usefulness of imaging spectroscopy to identify qualitative radiological background emissions when compared to airborne radiological survey data.

Bernacki, Bruce E.; Schweppe, John E.; Stave, Sean C.; Jordan, David V.; Kulisek, Jonathan A.; Stewart, Trevor N.; Seifert, Carolyn E.

2014-06-13T23:59:59.000Z

409

Synchrotron-Radiation-Based Moessbauer Spectroscopy  

SciTech Connect (OSTI)

We have developed a new method that yields Moessbauer absorption spectra using synchrotron radiation (SR); this method is applicable for almost all Moessbauer nuclides including those that cannot be measured by previous methods using radioisotope (RI) sources. The Moessbauer spectrum of the 68.752 keV excited state of {sup 73}Ge, which cannot be measured using a RI source, was measured using SR. Our results show that this method can be used to perform advanced Moessbauer spectroscopy measurements owing to the excellent features of SR.

Seto, Makoto [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-04 (Japan); Japan Atomic Energy Agency, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148 (Japan); CREST, Japan Science and Technology Agency, Saitama 332-0012 (Japan); Masuda, Ryo; Mitsui, Takaya [Japan Atomic Energy Agency, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148 (Japan); CREST, Japan Science and Technology Agency, Saitama 332-0012 (Japan); Higashitaniguchi, Satoshi; Kitao, Shinji; Kobayashi, Yasuhiro [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-04 (Japan); CREST, Japan Science and Technology Agency, Saitama 332-0012 (Japan); Inaba, Chika [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-04 (Japan); Yoda, Yoshitaka [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5198 (Japan); CREST, Japan Science and Technology Agency, Saitama 332-0012 (Japan)

2009-05-29T23:59:59.000Z

410

(Resonance ionization spectroscopy and its applications)  

SciTech Connect (OSTI)

The field of Resonance Ionization Spectroscopy grew out of work done in the Photophysics Group at Oak Ridge National Laboratory. As one of the original developers of this field the traveler has continued to attend this meeting on a regular basis. The traveler was originally asked to present an invited talk and to present part of a short course offered to graduate students attending the conference. Subsequently, the traveler was also asked to chair a session and to be a judge of the students papers entered in a contest for a $1000 first prize.

Payne, M.G.

1990-10-05T23:59:59.000Z

411

In Situ NMR Spectroscopy of Combustion  

Science Journals Connector (OSTI)

In situ nuclear magnetic resonance spectroscopy (NMR) of high-temperature reactions is of potential value for the investigation of catalytic combustion and other high-temperature applications of catalysts such as partial oxidation of hydrocarbons and steam reforming. ... Two-dimensional (2D) studies of gas exchange within different heat zones of the combustion process provide valuable insights into the gas-phase dynamics. ... This may be the case at the high combustion temperatures, but neither experimental nor theoretical xenon chemical shift data is available in current literature for temperatures above 1000 K. ...

Satyanarayana Anala; Galina E. Pavlovskaya; Prakash Pichumani; Todd J. Dieken; Michael D. Olsen; Thomas Meersmann

2003-10-07T23:59:59.000Z

412

Cavity-locked ring down spectroscopy  

DOE Patents [OSTI]

Distinct locking and sampling light beams are used in a cavity ring-down spectroscopy (CRDS) system to perform multiple ring-down measurements while the laser and ring-down cavity are continuously locked. The sampling and locking light beams have different frequencies, to ensure that the sampling and locking light are decoupled within the cavity. Preferably, the ring-down cavity is ring-shaped, the sampling light is s-polarized, and the locking light is p-polarized. Transmitted sampling light is used for ring-down measurements, while reflected locking light is used for locking in a Pound-Drever scheme.

Zare, Richard N. (Stanford, CA); Paldus, Barbara A. (Stanford, CA); Harb, Charles C. (Palo Alto, CA); Spence, Thomas (Union City, CA)

2000-01-01T23:59:59.000Z

413

Construction and Commissioning of a Collinear Laser Spectroscopy Setup at TRIGA Mainz and Laser Spectroscopy of Magnesium Isotopes at ISOLDE (CERN)  

E-Print Network [OSTI]

Construction and Commissioning of a Collinear Laser Spectroscopy Setup at TRIGA Mainz and Laser Spectroscopy of Magnesium Isotopes at ISOLDE (CERN)

Kraemer, Joerg

414

IR Spectroscopy Spectroscopy: Branch of science in which light or other electromagnetic radiation  

E-Print Network [OSTI]

is resolved into its component wavelengths to produce spectra, which are graphs of intensity vs. wavelength or frequency of radiation. Current usage broadens this definition to include some methods that don't involve the energy difference of 2 quantum levels of the sample of matter. hE = IR Spectroscopy Tool for examining

Sherrill, David

415

Controlling light at the nanoscale: imaging and spectroscopy...  

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

materials with spatial resolution down to nanometer length scales for, e.g., advanced solar energy and fuel cell applications. The extension of conventional optical spectroscopy...

416

Graphene and its derivatives : fabrication and Raman spectroscopy study.  

E-Print Network [OSTI]

??This thesis presents results on fabrication and Raman spectroscopy studies of graphene and its derivates. The works can be divided into two parts as follows. (more)

Cong, Chunxiao.

2012-01-01T23:59:59.000Z

417

Source Apportionment of Wastewater Using Bayesian Analysis of Fluorescence Spectroscopy.  

E-Print Network [OSTI]

??This research uses Bayesian analysis of fluorescence spectroscopy results to determine if wastewater from the Heber Valley Special Service District (HVSSD) lagoons in Midway, UT (more)

Blake, Daniel B.

2014-01-01T23:59:59.000Z

418

Chirped Laser Dispersion Spectroscopy with Directly Modulated Quantum Cascade Laser  

Science Journals Connector (OSTI)

A feasibility study of chirped laser dispersion spectroscopy (CLaDS) with utilizing direct modulation of a quantum cascade laser instead of external modulators is presented....

Hangauer, Andreas; Spinner, Georg; Nikodem, Michal; Wysocki, Gerard

419

Wave functions and their use in spectroscopy and phenomenology  

E-Print Network [OSTI]

We describe the calculation of Coulomb gauge wave functions for light quark systems, and their use as interpolating fields for excited state spectroscopy.

T. DeGrand; M. Hecht

1992-10-08T23:59:59.000Z

420

XRMS: X-Ray Spectroscopy of Magnetic Solids  

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

XRMS: X-Ray Spectroscopy of Magnetic Solids October 22-23, 2011 SLAC National Accelerator Laboratory, Menlo Park, CA More information...

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


421

Coherent States of Accelerated Relativistic Quantum Particles, Vacuum Radiation and the Spontaneous Breakdown of the Conformal SU(2,2) Symmetry  

E-Print Network [OSTI]

We give a quantum mechanical description of accelerated relativistic particles in the framework of Coherent States (CS) of the (3+1)-dimensional conformal group SU(2,2), with the role of accelerations played by special conformal transformations and with the role of (proper) time translations played by dilations. The accelerated ground state $\\tilde\\phi_0$ of first quantization is a CS of the conformal group. We compute the distribution function giving the occupation number of each energy level in $\\tilde\\phi_0$ and, with it, the partition function Z, mean energy E and entropy S, which resemble that of an "Einstein Solid". An effective temperature T can be assigned to this "accelerated ensemble" through the thermodynamic expression dE/dS, which leads to a (non linear) relation between acceleration and temperature different from Unruh's (linear) formula. Then we construct the corresponding conformal-SU(2,2)-invariant second quantized theory and its spontaneous breakdown when selecting Poincar\\'e-invariant degenerated \\theta-vacua (namely, coherent states of conformal zero modes). Special conformal transformations (accelerations) destabilize the Poincar\\'e vacuum and make it to radiate.

M. Calixto; E. Perez-Romero; V. Aldaya

2010-12-21T23:59:59.000Z

422

On the global uniqueness for the Einstein-Maxwell-scalar field system with a cosmological constant. Part 1: Well posedness and breakdown criterion  

E-Print Network [OSTI]

This paper is the first part of a trilogy dedicated to the following problem: given spherically symmetric characteristic initial data for the Einstein-Maxwell-scalar field system with a cosmological constant $\\Lambda$, with the data on the outgoing initial null hypersurface given by a subextremal Reissner-Nordstrom black hole event horizon, study the future extendibility of the corresponding maximal globally hyperbolic development (MGHD) as a "suitably regular" Lorentzian manifold. In this first part we establish well posedness of the Einstein equations for characteristic data satisfying the minimal regularity conditions leading to classical solutions. We also identify the appropriate notion of maximal solution, from which the construction of the corresponding MGHD follows, and determine breakdown criteria. This is the unavoidable starting point of the analysis; our main results will depend on the detailed understanding of these fundamentals. In the second part of this series we study the stability of the radius function at the Cauchy horizon. In the third and final paper we show that, depending on the decay rate of the initial data, mass inflation may or may not occur; in fact, it is even possible to have (non-isometric) extensions of the spacetime across the Cauchy horizon as classical solutions of the Einstein equations.

Joo L. Costa; Pedro M. Giro; Jos Natrio; Jorge Drumond Silva

2014-10-23T23:59:59.000Z

423

Scanning tunneling spectroscopy of suspended single-wall carbon nanotubes  

E-Print Network [OSTI]

Scanning tunneling spectroscopy of suspended single-wall carbon nanotubes B. J. LeRoy,a) S. G-wall carbon nanotubes that are freely suspended over a trench. The nanotubes were grown by chemical vapor on the freestanding portions of the nanotubes. Spatially resolved spectroscopy on the suspended portion of both

Dekker, Cees

424

Vibrational Raman Spectroscopy of High-temperature Superconductors  

E-Print Network [OSTI]

Vibrational Raman Spectroscopy of High-temperature Superconductors C. Thomsen and G. Kaczmarczyk after the discovery of high- critical-temperature Tc superconductors:2 while reports on Raman scattering Wiley & Sons Ltd, Chichester, 2002 #12;Vibrational Raman Spectroscopy of High-temperature

Nabben, Reinhard

425

production under ionizing radiation in aluminoborosilicate glasses by EPR spectroscopy.  

E-Print Network [OSTI]

1 Ti3+ production under ionizing radiation in aluminoborosilicate glasses by EPR spectroscopy. P irradiation of Ti4+ ions in aluminoborosilicate glasses have been studied by EPR spectroscopy at 20 K of the Ti3+ ion EPR spectra has shown three different Ti3+ environment attributed to one [VI] Ti3+ and two

Paris-Sud XI, Université de

426

Near-infrared spectroscopy of HD the barrier to linearity  

E-Print Network [OSTI]

Near-infrared spectroscopy of HD 3 above the barrier to linearity BY JENNIFER L. GOTTFRIED, transitions of HC 3 above the barrier to linearity have been observed. A highly sensitive near-infrared-adiabatic and radiative corrections is revealed. Keywords: HD 3 ; near-infrared spectroscopy; barrier to linearity 1

Oka, Takeshi

427

Optical Spectroscopy of Hydrogenic Atoms MIT Department of Physics  

E-Print Network [OSTI]

Optical Spectroscopy of Hydrogenic Atoms MIT Department of Physics (Dated: September 1, 2013) This experiment is an exercise in optical spectroscopy in a study of the spectra of "hydrogenic" atoms, i.e. atoms with one "optical" electron outside a closed shell of other electrons. Measurements include finding

Seager, Sara

428

New Results on Baryon Spectroscopy from MAMI  

SciTech Connect (OSTI)

An overview of the MAMI-C electron accelerator facility (E{sub 0} = 1.6 GeV) and the experimental setups of the A1 and A2 collaborations for electro- and photoproduction reactions is given. Several experimental results and their interpretations for baryon spectroscopy are discussed. The topics presented here are the beam-helicity asymmetry I{center_dot} for {pi}{pi} photoproduction in the second resonance region, the photoproduction of {pi}{sup 0{eta}} up to beam energies of {omega} = 1.4 GeV as a way to study the {Delta}(1700)D{sub 33} baryon, and polarisation observables in h electro- and photoproduction in order to investigate an unexpected s-d-wave phase shift and its possible implications for the nature of the S{sub 11}(1535) resonance.

Schumann, Sven [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, Mainz (Germany)

2010-08-05T23:59:59.000Z

429

Pressurised xenon as scintillator for gamma spectroscopy  

E-Print Network [OSTI]

Detectors based on liquid or gas xenon have been used and are in use for a number of applications, in particular for the detection of gamma rays. Xenon is a well-suited medium for gamma spectroscopy thanks to its high atomic number and, consequently, large cross-section for photo-electric absorption. This paper presents experimental studies of high pressure xenon as a scintillator, with the aim of developing a gamma ray detector for the detection of Special Nuclear Materials (SNM). The first goal was to study the dependence of the light yield and of the energy resolution on the thermodynamic conditions. We present preliminary results from an optimised version of the detector.

Resnati, F

2013-01-01T23:59:59.000Z

430

Diamond based single molecule magnetic resonance spectroscopy  

E-Print Network [OSTI]

The detection of a nuclear spin in an individual molecule represents a key challenge in physics and biology whose solution has been pursued for many years. The small magnetic moment of a single nucleus and the unavoidable environmental noise present the key obstacles for its realization. Here, we demonstrate theoretically that a single nitrogen-vacancy (NV) center in diamond can be used to construct a nano-scale single molecule spectrometer that is capable of detecting the position and spin state of a single nucleus and can determine the distance and alignment of a nuclear or electron spin pair. The proposed device will find applications in single molecule spectroscopy in chemistry and biology, such as in determining protein structure or monitoring macromolecular motions and can thus provide a tool to help unravelling the microscopic mechanisms underlying bio-molecular function.

Jianming Cai; Fedor Jelezko; Martin B. Plenio; Alex Retzker

2011-12-23T23:59:59.000Z

431

Core Level Spectroscopies Surface Science and X-Ray Spectroscopy Group  

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

Core Level Spectroscopy Creation and Decay of Core Holes Spectroscopic Techniques X-ray Photoelectron (XPS) X-ray Absorption (XAS) X-ray Emission (XES) Auger Electron (AES) Core holes are created by the ionization of a core electron in XPS and by excitation in XAS . The XPS and XAS final states are highly unstable and the core hole decays by non-radiant Auger relaxation (AES) or by radiant x-ray emission processes (XES). XPS and AES probe the unoccupied electronic stru cture, while XAS projects the unoccupied valence states of the system onto a particular atom. A brief description of the each of the different spectroscopies illustrated by schematic pictures of the creation and decay with data measured for N2 adsorbed on Ni(100) can be found by scrolling

432

Development of the charge exchange recombination spectroscopy and the beam emission spectroscopy on the EAST tokamak  

SciTech Connect (OSTI)

Charge eXchange Recombination Spectroscopy (CXRS) and Beam Emission Spectroscopy (BES) diagnostics based on a heating neutral beam have recently been installed on EAST to provide local measurements of ion temperature, velocity, and density. The system design features common light collection optics for CXRS and BES, background channels for the toroidal views, multi-chord viewing sightlines, and high throughput lens-based spectrometers with good signal to noise ratio for high time resolution measurements. Additionally, two spectrometers each has a tunable grating to observe any wavelength of interest are used for the CXRS and one utilizes a fixed-wavelength grating to achieve higher diffraction efficiency for the BES system. A real-time wavelength correction is implemented to achieve a high-accuracy wavelength calibration. Alignment and calibration are performed. Initial performance test results are presented.

Li, Y. Y.; Fu, J.; Lyu, B., E-mail: blu@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Du, X. W.; Li, C. Y.; Yu, Y.; Wang, Q. P. [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Y.; Yin, X. H.; Ye, M. Y.; Wan, B. N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026 (China); Hellermann, M. von [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM, Trilateral Euregio Cluster, 3430BE Nieuwegein (Netherlands); Shi, Y. J. [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026 (China); WCI for Fusion Theory, National Fusion Research Institute, 52 Eoeun-Dong, Yusung-Gu, Daejeon 305-333 (Korea, Republic of)

2014-11-15T23:59:59.000Z

433

images/logoetsf Introduction Electron Energy Loss Spectroscopy Applications: Nanotubes and Graphene Perspectives  

E-Print Network [OSTI]

images/logoetsf Introduction Electron Energy Loss Spectroscopy Applications: Nanotubes and Graphene excitations Francesco Sottile #12;Introduction Electron Energy Loss Spectroscopy Applications: Nanotubes excitations Francesco Sottile #12;Introduction Electron Energy Loss Spectroscopy Applications: Nanotubes

Botti, Silvana

434

Harmonic wavelet analysis of modulated tunable diode laser absorption spectroscopy signals  

E-Print Network [OSTI]

of the direct absorption characteristics of atomic or molecular absorption lines. This is accomplishedHarmonic wavelet analysis of modulated tunable diode laser absorption spectroscopy signals Hong analyses of tunable diode laser absorption spectroscopy signals were performed. The absorption spectroscopy

Cheng, Harry H.

435

E-Print Network 3.0 - applications spectroscopie du Sample Search...  

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

DivisionOptical Spectroscopy DivisionOptical Spectroscopy ... Source: McCombe, Bruce D. - Department of Physics, State University of New York at Buffalo Collection:...

436

Faraday rotation spectroscopy of nitrogen dioxide based on a widely tunable external cavity quantum cascade laser  

E-Print Network [OSTI]

Faraday rotation spectroscopy of nitrogen dioxide based on a widely tunable external cavity quantum: Faraday Rotation Spectroscopy, external-cavity quantum cascade laser, nitrogen dioxide, trace

437

A new high luminosity UHV orange type magnetic spectrometer used for depth selective Mssbauer spectroscopy  

Science Journals Connector (OSTI)

For Auger Electron Spectroscopy (AES) a combination with an electrostatic retardation field around the sample will provide an even higher resolution. For depth selective conversion electron Mssbauer spectroscopy...

B. Stahl; R. Gellert; G. Klingelhfer

1997-05-01T23:59:59.000Z

438

E-Print Network 3.0 - absorption spectroscopy techniques Sample...  

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

A partial sampling of these techniques includes: Absorption spectroscopy Atomic absorption... 109 3.4 Spectroscopic Sensors Spectroscopy is the scientific study of...

439

E-Print Network 3.0 - atomic spectroscopy programacion Sample...  

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

Name Summary: of an unknown metal ion in a biomolecule Atomic absorption spectroscopy or ICP spectroscopy (b) the presence... coordinated to...

440

E-Print Network 3.0 - atomic spectroscopy sympsoium Sample Search...  

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

Name Summary: of an unknown metal ion in a biomolecule Atomic absorption spectroscopy or ICP spectroscopy (b) the presence... coordinated to...

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


441

E-Print Network 3.0 - astrophotonic spectroscopy defining Sample...  

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

Summary: impedance spectroscopy technique to characterize supercapacitors. We define its metrology 7 and we present... to use two complementary methods: impedance spectroscopy...

442

E-Print Network 3.0 - annihilation lifetime spectroscopy Sample...  

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

spectroscopy... us the information on the exciton lifetime and exciton coherence time. It is therefore needed... to perform micro-photoluminescence (PL) spectroscopy...

443

INFRARED ABSORPTION SPECTROSCOPY OF CARBON MONOXIDE ON NICKEL FILMS: A LOW TEMPERATURE THERMAL DETECTION TECHNIQUE  

E-Print Network [OSTI]

A. B. Optical System Absorption Signal C. Small SignalNoise . Sensitivity of Absorption Spectroscopy EXPERIMENTSINFRARED ABSORPTION SPECTROSCOPY OF CARBON MONOXIDE ON

Bailey, Robert Brian

2011-01-01T23:59:59.000Z

444

E-Print Network 3.0 - absorption spectroscopy diagnostics Sample...  

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

Domain Spectroscopy From... Industrial applications: spectroscopy, imaging and security Terahertz: Research and Applications 12... in a volume Measuring of moisture in a volume...

445

E-Print Network 3.0 - anharmonic vibrational spectroscopy Sample...  

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

spectroscopy Page: << < 1 2 3 4 5 > >> 1 Chem 791 Molecular Spectroscopy Spring 2008 Chemistry 791 Summary: branches. - Anharmonicity: electrical; mechanical. Violation of v 1...

446

Soft X-Ray Microscopy and Spectroscopy at the Molecular Environmental...  

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

Soft X-Ray Microscopy and Spectroscopy at the Molecular Environmental Science Beamline at the Advanced Light Source. Soft X-Ray Microscopy and Spectroscopy at the Molecular...

447

BornOppenheimer breakdown and non-adiabatic lifetimes of rovibrational levels of D2 lying near the n=2 dissociation limit: Experiment and theory  

Science Journals Connector (OSTI)

The singlet gerade states of the hydrogen molecule are strongly affected by the breakdown of the BornOppenheimer approximation. This leads to strong non-adiabatic coupling resulting in large changes of the energies and lifetimes of the quantum levels compared to the values obtained in the BornOppenheimer or even the adiabatic levels of approximation. The non-adiabatic calculations of Quadrelli, Dressler, and Wolniewicz (1990) [7] (hereinafter QDW) for the three highest vibrational levels (?=44, 45, and 46) of the EF 1?g+ state of D2 predicted an enormous increase of the lifetimes upon excitation of just one quantum of rotational motion. However, although our experimental results for these levels just below the n=2 dissociation limit do show a strong increase in lifetime, the non-adiabatic lifetimes calculated by QDW are longer than experiment by as much as three orders of magnitude. In their work on isotopomers of hydrogen QDW and Yu and Dressler (1994) [5] published extensive summary tables of ab initio non-adiabatic coupling data. We present a technique which allows us to use their summary data to calculate approximate non-adiabatic ab initio lifetimes. The results reconcile our observed lifetimes with the non-adiabatic coupling from those previous ab initio calculations and also provide a detailed quantitative and qualitative understanding of the unusual rotational dependence of the lifetimes of these very highly excited levels. We also test the current technique by calculating the lifetimes of other levels involved in interactions with these EF levels and by calculating the lifetimes of the EF ?=33 level of H2, for which no corresponding level exists in the BornOppenheimer or adiabatic approximations.

Stephen C. Ross; Koichi Tsukiyama

2011-01-01T23:59:59.000Z

448

Early optical spectroscopy of supernova 1987A  

SciTech Connect (OSTI)

CCD spectroscopy of SN 1987A from February 24-28, 1987 is presented. Spectra with 10 A resolution and signal-to-noise ratio is excess of 200, over a range 3900 A to 9000 A, are reduced to flux relative to the continuum at 8000 A. Spectra as a function of time and nightly difference spectra are obtained. Strong and broad hydrogen Balmer P-Cygni profiles, increasing in intensity with time, and H-alpha absorption velocity decreasing from 19,000 km/s are seen. H-alpha velocity componnents up to 31,000 km/s are found on February 25 UT. The He I feature at 5400 A disappears after February 26 and Ca II at 8200 A appears strongly after February 27. Spectra as a function of angular distance from SN 1987A are also obtained, showing the adjacent nebular emission of the LMC. There is no evidence for a circumstellar shell. These data are most consistent with an unusually low envelope mass progenitor. 30 references.

Tyson, J.A.; Boeshaar, P.C.

1987-09-01T23:59:59.000Z

449

Validating the Melusine Gamma Spectroscopy Tool  

SciTech Connect (OSTI)

This technical report describes testing to evaluate the gamma spectroscopy tool, Melusine, under development by Pacific Northwest National Laboratory. The goal was to verify that the software can successfully be used to provide accurate results and statistical uncertainties for the detection of isotopes of interest and their activities. Of special interest were spectra similar to those produced by radionuclide stations that contribute to the Comprehensive Nuclear Test Ban Treaty Organizations International Monitoring System. Two data sets were used to test Melusines capabilities. The first was the result of a multi-lab calibration effort based on neutron activations produced at the University of California at Davis. The second was taken from the Proficiency Test Exercises conducted by the CTBTO directly in 2005. In 37 of 42 cases, Melusine produced results in agreement with the best answer presently available, in most cases with calculated uncertainties comparable to or better than competing analyses. In fact, Melusine technically provided one more result than CTBTOs PTE analyses that agreed with the book answer (Monte Carlo simulation). Despite these promising results, the Melusine software is still under development. Effort is especially needed to simplify its analysis process, improve stability, and provide user documentation. Some significant analysis tasks require further vetting, such as those to address summing effects. However, our test results indicate that Melusines calculations as presently implemented are sound and can be used to reliably analyze spectra from the CTBTOs radionuclide stations.

Erikson, Luke E.; Keillor, Martin E.; Stavenger, Timothy J.

2013-11-26T23:59:59.000Z

450

Ionization photophysics and spectroscopy of dicyanoacetylene  

SciTech Connect (OSTI)

Photoionization of dicyanoacetylene was studied using synchrotron radiation over the excitation range 825 eV, with photoelectron-photoion coincidence techniques. The absolute ionization cross-section and detailed spectroscopic aspects of the parent ion were recorded. The adiabatic ionization energy of dicyanoacetylene was measured as 11.80 0.01 eV. A detailed analysis of the cation spectroscopy involves new aspects and new assignments of the vibrational components to excitation of the quasi-degenerate A{sup 2}?{sub g}, B{sup 2}?{sub g}{sup +} states as well as the C{sup 2}?{sub u}{sup +} and D{sup 2}?{sub u} states of the cation. Some of the structured autoionization features observed in the 12.415 eV region of the total ion yield spectrum were assigned to vibrational components of valence shell transitions and to two previously unknown Rydberg series converging to the D{sup 2}?{sub u} state of C{sub 4}N{sub 2}{sup +}. The appearance energies of the fragment ions C{sub 4}N{sup +}, C{sub 3}N{sup +}, C{sub 4}{sup +}, C{sub 2}N{sup +}, and C{sub 2}{sup +} were measured and their heats of formation were determined and compared with existing literature values. Thermochemical calculations of the appearance potentials of these and other weaker ions were used to infer aspects of dissociative ionization pathways.

Leach, Sydney, E-mail: Sydney.Leach@obspm.fr, E-mail: Martin.Schwell@lisa.u-pec.fr; Champion, Norbert [LERMA UMR CNRS 8112, Observatoire de Paris-Meudon, 5 place Jules-Jansen, 92195 Meudon (France)] [LERMA UMR CNRS 8112, Observatoire de Paris-Meudon, 5 place Jules-Jansen, 92195 Meudon (France); Schwell, Martin, E-mail: Sydney.Leach@obspm.fr, E-mail: Martin.Schwell@lisa.u-pec.fr; Bnilan, Yves; Fray, Nicolas; Gazeau, Marie-Claire [LISA UMR CNRS 7583, Universit Paris-Est Crteil and Universit Paris Diderot, Institut Pierre Simon Laplace, 61 Avenue du Gnral de Gaulle, 94010 Crteil (France)] [LISA UMR CNRS 7583, Universit Paris-Est Crteil and Universit Paris Diderot, Institut Pierre Simon Laplace, 61 Avenue du Gnral de Gaulle, 94010 Crteil (France); Garcia, Gustavo A.; Gaie-Levrel, Franois [Synchrotron SOLEIL, LOrme des Merisiers, St. Aubin, B.P. 48, 91192 Gif-sur-Yvette Cedex (France)] [Synchrotron SOLEIL, LOrme des Merisiers, St. Aubin, B.P. 48, 91192 Gif-sur-Yvette Cedex (France); Guillemin, Jean-Claude [Institut des Sciences Chimiques de Rennes, Ecole Nationale Suprieure de Chimie de Rennes, CNRS UMR 6226, 11 Alle de Beaulieu, CS 50837, 35708 Rennes Cedex 7 (France)] [Institut des Sciences Chimiques de Rennes, Ecole Nationale Suprieure de Chimie de Rennes, CNRS UMR 6226, 11 Alle de Beaulieu, CS 50837, 35708 Rennes Cedex 7 (France)

2013-11-14T23:59:59.000Z

451

Introduction of coherence in astrophysical spectroscopy  

E-Print Network [OSTI]

By confusing the radiance of a single mode light beam, constant in a transparent medium, with the irradiance which decreases away from the source, Menzel purports to show that coherent interactions of light with the diluted media of astrophysics, are negligible. Therefore, to study the interaction of light with gases, astrophysicists use Monte Carlo computations which work to study nuclear systems, but not optics: optical modes which may be defined in inhomogeneous media or for the emissions of single atoms interact coherently with these systems: a unique formula represents, according to the sign of a parameter, absorption and coherent emission. The optical and spectroscopic properties of a very simple model, an extremely hot source in an isotropic cloud of pure, low pressure, initially cold, huge hydrogen cloud are studied using Planck's and Einstein's theories. The similarities of the images and the spectra of this simple model with astronomical observations, for instance of SNR1987A, Einstein cross, lyman break galaxies, quasars,... is so large that this model may be an elementary first step in the study of many astrophysical objects. Adaptations of the model to complex astrophysical systems could represent them using only the old, standard theories of physics commonly used in laser spectroscopy.

Jacques Moret-Bailly

2010-02-08T23:59:59.000Z

452

Spectroscopy of Hyades L dwarf candidates  

E-Print Network [OSTI]

We present the results of photometric, astrometric, and spectroscopic follow-up of L dwarf candidates identified in the Hyades cluster by Hogan et al. (2008). We obtained low-resolution optical spectroscopy with the OSIRIS spectrograph on the Gran Telescopio de Canarias for all 12 L dwarf candidates as well as new J-band imaging for a subsample of eight to confirm their proper motion. We also present mid-infrared photometry from the Wise Field Infrared Survey Explorer (WISE) for the Hyades L and T dwarf candidates and estimate their spectroscopic distances, effective temperatures, and masses. We confirm the cool nature of several L dwarf candidates and confirm astrometrically their membership, bridging the gap between the coolest M dwarfs and the two T dwarfs previously reported in the Hyades cluster. These members represent valuable spectral templates at an age of 625 Myr and slightly super solar metallicity (Fe/H=+0.13). We update the Hyades mass function across the hydrogen-burning limit and in the substel...

Lodieu, N; Bejar, V J S

2014-01-01T23:59:59.000Z

453

Measurement of Stark widths and shifts of Ca II spectral lines  

Science Journals Connector (OSTI)

......Stark widths and shifts of Caii spectral lines J. A. Aguilera 1 C. Aragon 1 J. Manrique...Spain Stark widths and shifts of Ca ii lines have been measured by laser-induced breakdown...available in the literature. atomic data|line: profiles|plasmas| 1 INTRODUCTION Measurement......

J. A. Aguilera; C. Aragn; J. Manrique

2014-01-01T23:59:59.000Z

454

FRONTIER SYNCHROTRON INFRARED SPECTROSCOPY BEAMLINE UNDER EXTREME CONDITIONS (FIS)  

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

FRONTIER SYNCHROTRON INFRARED SPECTROSCOPY FRONTIER SYNCHROTRON INFRARED SPECTROSCOPY BEAMLINE UNDER EXTREME CONDITIONS (FIS) Proposal Team: L. Carr 1 , D. Dolan 2 , R. Hemley 3 , S. Jacobson 4 , S. Karato 5 , Z. Liu 3 , W. Panero 6 , M. Pravica 7 , and T. Zhou 8 1 Brookhaven National Laboratory, 2 Sandia National Laboratories, 3 Carnegie Institution of Washington, 4 Northwestern University, 5 Yale University, 6 Ohio State University, 7 University of Nevada, 8 New Jersey Institute of Technology TECHNIQUES AND CAPABILITIES APPLICATIONS SPECIFIC PROJECTS / ADDITIONAL INFORMATION * TECHNIQUE(S): Fourier transform infrared spectroscopy; Raman and visible spectroscopy; Diamond anvil cell techniques for static high pressure; Gas-gun launchers for dynamic compression; Cryogenic techniques combined with DACs;

455

A Different Laboratory Tale: Fifty Years of Mssbauer Spectroscopy  

Science Journals Connector (OSTI)

I explore the fifty-year development of Mssbauer spectroscopy by focusing on three episodes in its development at Argonne National Laboratory: work by nuclear physicists using radioactive sources in the early...

Catherine Westfall

2006-05-01T23:59:59.000Z

456

Magneto-optical spectroscopy of metallic carbon nanotubes.  

E-Print Network [OSTI]

??Through polarization-dependent magneto-optical absorption spectroscopy, the magnetic susceptibility anisotropy for metallic single-walled carbon nanotubes has been extracted and found to be up to 4x greater (more)

Searles, Thomas A., Jr

2010-01-01T23:59:59.000Z

457

CODED SPECTROSCOPY FOR ETHANOL DETECTION IN DIFFUSE, FLUORESCENT MEDIA  

E-Print Network [OSTI]

ABSTRACT CODED SPECTROSCOPY FOR ETHANOL DETECTION IN DIFFUSE, FLUORESCENT MEDIA by Scott Thomas Mc FOR ETHANOL DETECTION IN DIFFUSE, FLUORESCENT MEDIA by Scott Thomas McCain Department of Electrical

458

The Application of IR Spectroscopy to the Investigation of Minerals  

Science Journals Connector (OSTI)

Traditionally, the application of IR spectroscopy in mineralogy is reduced to the determination of wavelengths or frequencies of discrete absorption maxima. These values are brought in correspondence with normal ...

Nikita V. Chukanov

2014-01-01T23:59:59.000Z

459

Testing Spin-Statistics Connection by Highly Sensitive Spectroscopy  

E-Print Network [OSTI]

Testing Spin-Statistics Connection by Highly Sensitive Spectroscopy of CO2 Y.-H. Lien ,Y.-L. Hsu ,Y #12;Experimental Scheme Searching for the very weak or even nonexistent J=(2n+1) transitions 2 µm 0000

Shy,Jow-Tsong

460

Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy  

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

Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned...

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


461

Photoelectron Spectroscopy of Free Multiply Charged Keggin Anions...  

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

Free Multiply Charged Keggin Anions ?-PM12O403- (M Mo, W) in the Gas Phase. Photoelectron Spectroscopy of Free Multiply Charged Keggin Anions ?-PM12O403- (M Mo,...

462

Hyperfine Studies of Lithium Vapor using Saturated Absorption Spectroscopy  

E-Print Network [OSTI]

the frequency of a laser with respect to an atomic spectral feature.[20] As such, saturated absorptionHyperfine Studies of Lithium Vapor using Saturated Absorption Spectroscopy? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.3 Broadening Mechanisms . . . . . . . . . . . . . . . . . . . . . 15 3.4 Saturated Absorption

Cronin, Alex D.

463

Detection of Physiologically Relevant Alcohol Concentrations Using Raman Spectroscopy  

E-Print Network [OSTI]

This is the first step in a series of studies to test the feasibility of using Raman Spectroscopy (RS) to non-invasively detect physiologically relevant blood alcohol concentrations. Blood tests, urine tests, and the breathalyzer are currently...

McKay, Joshua L.

2006-08-16T23:59:59.000Z

464

Photoelectron Spectroscopy under Ambient Pressure and Temperature Conditions  

E-Print Network [OSTI]

than ~ 100 l/s in a typical UHV system, so this produces aof spectroscopy chamber p 0 = UHV~ torr preparation chamberpumping system was capable of UHV performance and maintained

Ogletree, D. Frank

2009-01-01T23:59:59.000Z

465

Laser Spectroscopy and Optical Diagnostics of Combustion Processes  

Science Journals Connector (OSTI)

Tunable diode laser absorption spectroscopy of temperature and species (NO,H2O,CO,CO2,UHC) with applications in coal fired powerplants, gasifiers and IC engines. Wavelength modulation...

Hanson, Ronald K

466

Early diagnosis of cancer using light scattering spectroscopy  

E-Print Network [OSTI]

This thesis presents a novel optical technique, light scattering spectroscopy (LSS), developed for quantitative characterization of tissue morphology as well as in vivo detection and diagnosis of the diseases associated ...

Backman, Vadim, 1973-

2001-01-01T23:59:59.000Z

467

Thermal unfolding dynamics of proteins probed by nonlinear infrared spectroscopy  

E-Print Network [OSTI]

This thesis presents spectroscopic approaches to study the thermal unfolding dynamics of proteins. The spectroscopic tool is nonlinear infrared (IR) spectroscopy of the protein amide I band. Among various nonlinear IR ...

Chung, Hoi Sung

2007-01-01T23:59:59.000Z

468

Quantitative biological Raman spectroscopy for non-invasive blood analysis  

E-Print Network [OSTI]

The long term goal of this project is the measurement of clinically-relevant analytes in the blood tissue matrix of human subjects using near-infrared Raman spectroscopy, with the shorter term research directed towards ...

Shih, Wei-Chuan

2007-01-01T23:59:59.000Z

469

Microsoft PowerPoint - SpectroscopyTechniques_XANES  

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

Near Edge Spectroscopy (XANES) Near Edge Spectroscopy (XANES) XANES: XANES: * Element specific * Highly sensitive to bond angles, bond lengths, and the presence of adsorbates NEXAFS (Near Edge X-ray Absorption Fine Structure): * Synonymous with XANES but soft x-ray spectroscopy (< 1keV) * Fine structure within about 30 eV of the absorption edge EXAFS XANES / XRD C bi i S EXAFS-XANES / XRD Combination Spectroscopy * XAFS-XANES and XRD techniques give complementary information about the structure of materials. * XRD is effective in materials with medium- to long-range A typical XANES Spectrum XRD is effective in materials with medium to long range order while XAFS provides short-range information. *The simultaneous collection of the XRD and XAFS- XANES data in situ will allow

470

Femtosecond time-resolved spectroscopy of coherent oscillations in nanomaterials  

E-Print Network [OSTI]

FEMTOSECOND TIME-RESOLVED SPECTROSCOPY OF COHERENT OSCILLATIONS IN NANOMATERIALS A Dissertation by SERGUEI JEREBTSOV Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of DOCTOR OF PHILOSOPHY May 2007 Major Subject: Physics FEMTOSECOND TIME-RESOLVED SPECTROSCOPY OF COHERENT OSCILLATIONS IN NANOMATERIALS A Dissertation by SERGUEI JEREBTSOV Submitted to the Office of Graduate Studies of Texas A&M University in partial...

Jerebtsov, Serguei Nikolaevich

2009-05-15T23:59:59.000Z

471

Book Review of Handbook of Molecular Force Spectroscopy  

Science Journals Connector (OSTI)

The measurement of forces at the molecular level is an active and exciting area of research that has found application in a diverse range of disciplines, including chemistry, biology, and physics. ... In conclusion, Noys Handbook of Molecular Force Spectroscopy is both a timely and useful summary of fundamental aspects of molecular force spectroscopy, and I believe it would make a worthwhile addition to any good scientific library. ...

Matthew F. Paige

2008-06-04T23:59:59.000Z

472

Vibrational Spectroscopy: Recent Developments to Revolutionize Forensic Science  

Science Journals Connector (OSTI)

Vibrational Spectroscopy: Recent Developments to Revolutionize Forensic Science ... The National Academy of Sciences published a report outlining the current state of forensic science in the US, including issues being faced and necessary changes (National Research Council: Washington, D.C., 2009). ... These qualities, along with their automated capabilities, make Raman and IR spectroscopy model techniques according to the requirements outlined by the National Academy of Sciences. ...

Claire K. Luber; Kyle C Doty; Justin Bueno; Lenka Halamkova; Igor K. Lednev

2014-11-10T23:59:59.000Z

473

Photoelectron spectroscopy as a tool of lignin chemistry  

SciTech Connect (OSTI)

Many efforts in systematic elucidation of lignin properties start from the properties of the lignin subunits. In this paper, the authors provide the vertical ionization potentials (IP) of a representative set of lignin model compound. Gas phase photoelectron spectroscopy enables them to determine ionization potentials and makes it possible to deduce the electron structure of molecules within the limitations of Koopman's theorem. They discuss reasons why photoelectron spectroscopy might be a valuable method for the study of lignin properties.

Shevchenko, S.M.; Zarubin, M.Y. (Leningrad Forest Technical Academy, 194018 Leningrad (SU))

1989-05-01T23:59:59.000Z

474

Nonlinear optical spectroscopy of diamond surfaces  

SciTech Connect (OSTI)

Second harmonic generation (SHG) and infrared-visible sum frequency generation (SFG) spectroscopies have been shown to be powerful and versatile for studying surfaces with submonolayer sensitivity. They have been used in this work to study bare diamond surfaces and molecular adsorption on them. In particular, infrared-visible SFG as a surface vibrational spectroscopic technique has been employed to identify and monitor in-situ surface bonds and species on the diamond (111) surface. The CH stretch spectra allow us to investigate hydrogen adsorption, desorption, abstraction, and the nature of the hydrogen termination. The C(111) surface dosed with atomic hydrogen was found to be in a monohydride configuration with the hydrogen atoms situated at top-sites. The ratio of the abstraction rate to the adsorption rate was appreciable during atomic hydrogen dosing. Kinetic parameters for thermal desorption of H on C(111) were determined showing a near first-order kinetics. For the fully H-terminated (111) surface, a large (110 cm{sup {minus}1}) anharmonicity and {approximately}19 psec lifetime were measured for the first-excited CH stretch mode. The bare reconstructed C(111)-(2 {times} l) surface showed the presence of CC stretch modes which were consistent with the Pandey {pi}-bonded chain structure. When exposed to the methyl radical, the SFG spectra of the C(111) surface showed features suggesting the presence of adsorbed methyl species. After heating to sufficiently high temperatures, they were converted into the monohydride species. Preliminary results on the hydrogen-terminated diamond (100) surface are also presented.

Chin, R.P.

1995-04-01T23:59:59.000Z

475

Neutrino Spectroscopy with Atoms and Molecules  

E-Print Network [OSTI]

We give a comprehensive account of our proposed experimental method of using atoms or molecules in order to measure parameters of neutrinos still undetermined; the absolute mass scale, the mass hierarchy pattern (normal or inverted), the neutrino mass type (Majorana or Dirac), and the CP violating phases including Majorana phases. There are advantages of atomic targets, due to the closeness of available atomic energies to anticipated neutrino masses, over nuclear target experiments. Disadvantage of using atomic targets, the smallness of rates, is overcome by the macro-coherent amplification mechanism. The atomic or molecular process we use is a cooperative deexcitation of a collective body of atoms in a metastable level |e> emitting a neutrino pair and a photon; |e> -> |g> + gamma + nu_i nu_j where nu_i's are neutrino mass eigenstates. The macro-coherence is developed by trigger laser irradiation. We discuss aspects of the macro-coherence development by setting up the master equation for the target quantum state and propagating electric field. With a choice of heavy target atom or molecule such as Xe or I_2 that has a large M1 x E1 matrix element between |e> and |g>, we show that one can determine three neutrino masses along with the mass hierarchy pattern by measuring the photon spectral shape. If one uses a target of available energy of a fraction of 1 eV, Majorana CP phases may be determined. Our master equation, when applied to E1 x E1 transition such as pH_2 vibrational transition Xv=1 -> 0, can describe explosive PSR events in which most of the energy stored in |e> is released within a few nanoseconds. The present paper is intended to be self-contained explaining some details related theoretical works in the past, and further reports new simulations and our ongoing experimental efforts of the project to realize the neutrino mass spectroscopy using atoms/molecules.

Atsushi Fukumi; Susumu Kuma; Yuki Miyamoto; Kyo Nakajima; Itsuo Nakano; Hajime Nanjo; Chiaki Ohae; Noboru Sasao; Minoru Tanaka; Takashi Taniguchi; Satoshi Uetake; Tomonari Wakabayashi; Takuya Yamaguchi; Akihiro Yoshimi; Motohiko Yoshimura

2012-11-21T23:59:59.000Z

476

THE DEEP SWIRE FIELD. III. WIYN SPECTROSCOPY  

SciTech Connect (OSTI)

We present the results of spectroscopy using HYDRA on the WIYN 3.5 m telescope of objects in the deep SWIRE radio field. The goal of the project was to determine spectroscopic redshifts for as many of the brighter objects in the field as possible, especially those detected in the radio and at 24 {mu}m. These redshifts are primarily being used in studies of galaxy evolution and the connection of that evolution to active galactic nuclei and star formation. Redshifts measured for 365 individual objects are reported. The redshifts range from 0.03 to 2.5, mostly with z < 0.9. The sources were selected to be within the WIYN HYDRA field of approximately 30' in radius from the center of the SWIRE deep field, 10{sup h}46{sup m}00{sup s}, 59{sup 0}01'00'' (J2000). Optical sources for spectroscopic observation were selected from an r-band image of the field. A priority list of spectroscopic targets was established in the following order: 20 cm detections, 24 m detections, galaxies with r < 20 and the balance made up of fainter galaxies in the field. We provide a table listing the galaxy positions, measured redshift and error, and note any emission lines that were visible in the spectrum. In practice, almost all the galaxies with r < 19 were observed including all of the radio sources and most of the 24 {mu}m sources with r < 20 and a sample of radio sources which had fainter optical counterparts on the r-band image.

Owen, Frazer N. [National Radio Astronomy Observatory , P.O. Box O, Socorro, NM 87801 (United States); Morrison, G. E. [Institute for Astronomy, University of Hawaii, Honolulu, 96822 (United States)], E-mail: fowen@nrao.edu

2009-06-15T23:59:59.000Z

477

Fundamentals of Quantum Chemistry: Molecular Spectroscopy and Modern Electronic Structure Computations (Mueller, Michael R.)  

Science Journals Connector (OSTI)

Fundamentals of Quantum Chemistry: Molecular Spectroscopy and Modern Electronic Structure Computations (Mueller, Michael R.) ...

Robert G. Mortimer

2003-01-01T23:59:59.000Z

478

Microbial breakdown of Phaeocystis mucopolysaccharides  

Science Journals Connector (OSTI)

Department of Microbiology, University of Groningen, P.O. Box 14, 9750 AA Haren, The Netherlands. Marion van Rijssel. Department of Marine Biology,...

1999-08-06T23:59:59.000Z

479

Study of asymmetries of Cd(Zn)Te devices investigated using photo-induced current transient spectroscopy, Rutherford backscattering, surface photo-voltage spectroscopy, and gamma ray spectroscopies  

SciTech Connect (OSTI)

Despite these recent advancements in preparing the surface of Cd(Zn)Te devices for detector applications, large asymmetries in the electronic properties of planar Cd(Zn)Te detectors are common. Furthermore, for the development of patterned electrode geometries, selection of each electrode surface is crucial for minimizing dark current in the device. This investigation presented here has been carried out with three objectives. Each objective is oriented towards establishing reliable methods for the selection of the anode and cathode surfaces independent of the crystallographic orientation. The objectives of this study are (i) investigate how the asymmetry in I-V characteristics of Cd(Zn)Te devices may be associated with the TeO2 interfacial layer using Rutherford backscattering to study the structure at the Au-Cd(Zn)Te interface, (ii) develop an understanding of how the concentration of the active traps in Cd(Zn)Te varies with the external bias, and (iii) propose non-destructive methods for selection of the anode and cathode which are independent of crystallographic orientation. The spectroscopic methods employed in this investigation include Rutherford backscattering spectroscopy, photo-induced current transient spectroscopy, and surface photo-voltage spectroscopy, as well as gamma ray spectroscopy to demonstrate the influence on detector properties.

Crocco, J.; Bensalah, H.; Zheng, Q.; Dieguez, E. [Crystal Growth Laboratory, Universidad Autonoma de Madrid, Madrid Spain (Spain); Corregidor, V.; Avles, E. [Instituto Tecnologico e Nuclear UFA, Sacavem (Portugal); Castaldini, A.; Fraboni, B.; Cavalcoli, D.; Cavallini, A. [PHoS Laboratory, Department of Physics, University of Bologna, Bologna (Italy); Vela, O. [Centro de Investigacion Energeticas Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain)

2012-10-01T23:59:59.000Z

480

Ion dip spectroscopy of cold molecules and ions. Progress report  

SciTech Connect (OSTI)

During the past year, the main emphasis in this research program has been on multiphoton ionization spectroscopy of aromatic clusters. This is being pursued in addition to continuing work in areas of ion dip spectroscopy and ion fragmentation spectroscopy. The program has the overall objective of developing improved ultrasensitive molecular detection methods based on multiphoton laser spectroscopy. Photoionization techniques are employed due to their extreme sensitivity combined with mass selectivity. The combination of these two features has led to the current capability to study molecular clusters of specific sizes with high spectral resolution. Clusters are formed in abundance in a supersonic expansion, where they are excited and ionized by an ultraviolet laser beam. The studies reported here are principally based on simple resonant excitation of clusters, followed by one-photon ionization. For the naphthalene clusters, a single laser wavelength suffices for both excitation steps. Additional investigations have been carried out to measure excited state cluster ionization spectra and cluster ion fragmentation spectra. Results from these measurements are not yet sufficiently advanced to report in detail, however the preliminary data support the importance of recently proposed new fundamental ionization mechanisms in clusters. This brief report summarizes results described in more detail in the preprint titled: Resonant two-photon ionization spectroscopy of naphthalene clusters and the preprint titled: Resonance interactions in naphthalene clusters. It also briefly describes preliminary undisclosed results of current investigations.

Wessel, J.E.

1988-08-23T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Analysis Tools for Next-Generation Hadron Spectroscopy Experiments  

E-Print Network [OSTI]

The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopy in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near...

Battaglieri, M; Celentano, A; Chung, S -U; D'Angelo, A; De Vita, R; Dring, M; Dudek, J; Eidelman, S; Fegan, S; Ferretti, J; Fox, G; Galata, G; Garcia-Tecocoatzi, H; Glazier, D I; Grube, B; Hanhart, C; Hoferichter, M; Hughes, S M; Ireland, D G; Ketzer, B; Klein, F J; Kubis, B; Liu, B; Masjuan, P; Mathieu, V; McKinnon, B; Mitchell, R; Nerling, F; Paul, S; Pelaez, J R; Rademacker, J; Rizzo, A; Salgado, C; Santopinto, E; Sarantsev, A V; Sato, T; Schlter, T; da Silva, M L L; Stankovic, I; Strakovsky, I; Szczepaniak, A; Vassallo, A; Walford, N K; Watts, D P; Zana, L

2014-01-01T23:59:59.000Z

482

INFRARED ABSORPTION SPECTROSCOPY AND CHEMICAL KINETICS OF FREE RADICALS  

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

mNAL PERFORMANCE REPORT mNAL PERFORMANCE REPORT for INFRARED ABSORPTION SPECTROSCOPY AND CHEMICAL KINETICS OF FREE RADICALS DE-FG05-85ER13439 1-AUG-1985 to 31-JUL-1994 Robert F. Curl and Graham P. Glass Principal Investigators Introduction This research was directed at the detection, monitoring, and study (by infrared absorption spectroscopy) of the chemical kinetic behavior of small free radical species thought to be important intermediates in combustion. The work typically progressed from the detection and analysis of the infrared spectrum of combustion radical to the utilization of the infrared spectrum thus obtained in the investigation of chemical kinetics of the radical species. The methodology employed was infrared kinetic spectroscopy. In this technique the radical is produced by UV flash photolysis using an excimer laser and then

483

Optical and plasmonic spectroscopy with cantilever shaped materials  

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

plasmonic spectroscopy with cantilever shaped materials plasmonic spectroscopy with cantilever shaped materials This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2011 J. Phys. D: Appl. Phys. 44 445102 (http://iopscience.iop.org/0022-3727/44/44/445102) Download details: IP Address: 128.219.49.13 The article was downloaded on 28/12/2012 at 18:01 Please note that terms and conditions apply. View the table of contents for this issue, or go to the journal homepage for more Home Search Collections Journals About Contact us My IOPscience IOP PUBLISHING JOURNAL OF PHYSICS D: APPLIED PHYSICS J. Phys. D: Appl. Phys. 44 (2011) 445102 (9pp) doi:10.1088/0022-3727/44/44/445102 Optical and plasmonic spectroscopy with cantilever shaped materials L Tetard 1 , A Passian 1,2 , R H Farahi 1 , B H Davison 1 , A L Lereu 3 and T Thundat

484

2010 GRC VIBRATIONAL SPECTROSCOPY AUGUST 1 - AUGUST 6, 2010  

SciTech Connect (OSTI)

The Vibrational Spectroscopy conference focuses on using vibrational spectroscopy to probe structure and dynamics of molecules in gases, liquids, and at interfaces. The conference explores the wide range of state-of-the-art techniques based on vibrational motion. These techniques span the fields of time-domain, high-resolution frequency-domain, spatially-resolved, nonlinear and multidimensional spectroscopies. The conference highlights the application of these techniques in chemistry, materials, biology, and medicine. The theory of molecular vibrational motion and its connection to spectroscopic signatures and chemical reaction dynamics is the third major theme of the meeting. The goal is to bring together a collection of researchers who share common interests and who will gain from discussing work at the forefront of several connected areas. The intent is to emphasize the insights and understanding that studies of vibrations provide about a variety of molecular systems ranging from small polyatomic molecules to large biomolecules and nanomaterials.

Brooks Pate

2010-08-06T23:59:59.000Z

485

Single electron detection and spectroscopy via relativistic cyclotron radiation  

E-Print Network [OSTI]

It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a novel radiofrequency spec- trometer. We observe the cyclotron radiation emitted by individual magnetically-trapped electrons that are produced with mildly-relativistic energies by a gaseous radioactive source. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta elec- tron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments.

D. M. Asner; R. F. Bradley; L. de Viveiros; P. J. Doe; J. L. Fernandes; M. Fertl; E. C. Finn; J. A. Formaggio; D. Furse; A. M. Jones; J. N. Kofron; B. H. LaRoque; M. Leber; E. L. McBride; M. L. Miller; P. Mohanmurthy; B. Monreal; N. S. Oblath; R. G. H. Robertson; L. J Rosenberg; G. Rybka; D. Rysewyk; M. G. Sternberg; J. R. Tedeschi; T. Thummler; B. A. VanDevender; N. L. Woods

2014-08-22T23:59:59.000Z

486

Photon Sciences | Beamlines | SRX: Submicron Resolution X-ray Spectroscopy  

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

SRX: Submicron Resolution X-ray Spectroscopy SRX: Submicron Resolution X-ray Spectroscopy Poster | Fact Sheet | Preliminary Design Report Scientific Scope Scientific communities such as environmental sciences, life sciences, and material sciences have identified the need to develop analytical resources to advance the understanding of complex natural and engineered systems that are heterogeneous on the micron to nanometer scale. These needs for high intensity x-ray nanoprobes resulted in the commitment of the NSLS-II Project to build the Submicron Resolution X-ray (SRX) Spectroscopy beamline showing a unique combination of high spectral resolution over a very broad energy range and very high beam intensity in a sub-micrometer spot. NSLS-II will provide one of the best sources in the world for such an instrument.

487

2-2 Environmental Spectroscopy & Biogeochemistry Facility  

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

ES&B Overview ES&B Overview Environmental Spectroscopy & Biogeochemistry Facility The Environmental Spectroscopy & Biogeochemistry (ES&B) Facility focuses on environ- mental molecular science and application of the fundamental concepts of physical chemistry to the study of chemical reactions in heterogeneous natural materials, with an emphasis on soil and subsurface systems. The ES&B Facility staff, along with other Pacific Northwest National Laboratory (PNNL) staff, form a multidisciplinary organization with expertise in chemistry, mineral physics, geochemistry, soil chemistry, microbiology, hydrology, and environmental engineering. Capabilities are available for materials characterization, aqueous-phase and solid-phase speciation and reaction/kinetic measurements, analytical environmental chemistry, molecular

488

Core-level spectroscopy of thin oxides and oxynitrides  

SciTech Connect (OSTI)

Several spectroscopic methods are discussed that use core levels, such as photoelectron spectroscopy and absorption spectroscopy with photoelectron or fluorescence detection. Measurements are presented on the desorption of a chemical oxide and the growth of oxynitrides with N{sub 2}0 on Si(100). The stoichiometry is found to change strongly with thickness, from a nitrogen-terminated Si surface to a nearly-pure oxide in the outer region of 40--60 {Angstrom} films. Using a third generation synchrotron beam line a sensitivity of better than a tenth of a monolayer is achieved by a simple photocurrent measurement.

Himpsel, F.J.; Akatsu, H. [International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center; Carlisle, J.A. [Lawrence Livermore National Lab., CA (United States)] [and others

1994-07-19T23:59:59.000Z

489

Infrared absorption spectroscopy and chemical kinetics of free radicals  

SciTech Connect (OSTI)

This research is directed at the detection, monitoring, and study of chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. During the last year, infrared kinetic spectroscopy using excimer laser flash photolysis and color-center laser probing has been employed to study the high resolution spectrum of HCCN, the rate constant of the reaction between ethynyl (C{sub 2}H) radical and H{sub 2} in the temperature region between 295 and 875 K, and the recombination rate of propargyl (CH{sub 2}CCH) at room temperature.

Curl, R.F.; Glass, G.P. [Rice Univ., Houston, TX (United States)

1993-12-01T23:59:59.000Z

490

Multiplexed absorption tomography with calibration-free wavelength modulation spectroscopy  

SciTech Connect (OSTI)

We propose a multiplexed absorption tomography technique, which uses calibration-free wavelength modulation spectroscopy with tunable semiconductor lasers for the simultaneous imaging of temperature and species concentration in harsh combustion environments. Compared with the commonly used direct absorption spectroscopy (DAS) counterpart, the present variant enjoys better signal-to-noise ratios and requires no baseline fitting, a particularly desirable feature for high-pressure applications, where adjacent absorption features overlap and interfere severely. We present proof-of-concept numerical demonstrations of the technique using realistic phantom models of harsh combustion environments and prove that the proposed techniques outperform currently available tomography techniques based on DAS.

Cai, Weiwei; Kaminski, Clemens F., E-mail: cfk23@cam.ac.uk [Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA (United Kingdom)

2014-04-14T23:59:59.000Z

491

Skin cancer detection by oblique-incidence diffuse reflectance spectroscopy  

E-Print Network [OSTI]

Skin cancer is the most common form of cancer and it is on the rise. If skin cancer is diagnosed early enough, the survival rate is close to 90%. Oblique-incidence diffuse reflectance (OIR) spectroscopy offers a technology that may be used...

Smith, Elizabeth Brooks

2009-05-15T23:59:59.000Z

492

Laser and Spectroscopy Facility Center For Microanalysis of Materials  

E-Print Network [OSTI]

Laser and Spectroscopy Facility Center For Microanalysis of Materials Frederick Seitz Materials Research Laboratory Form revised 03 November 2009 Precautions for the safe use of lasers 1. NEVER LOOK DIRECTLY INTO ANY LASER BEAM, REGARDLESS OF POWER. 2. The lab door safety lamp "LASER in USE" must

Braun, Paul

493

Instrumentation for Far-infrared Spectroscopy Peter R. Griffiths1  

E-Print Network [OSTI]

at one end with an infrared transparent window (A) through which radiation reaches a thin absorbing film- and Far-Infrared Spectroscopy Window Incident radiation A B Absorbing film Pneumatic chamber Ballasting passes through the window onto a blackened film, causing the pressure of the gas in the pneumatic chamber

Homes, Christopher C.

494

Absorption spectroscopy of individual single-walled carbon nanotubes  

E-Print Network [OSTI]

Absorption spectroscopy of individual single-walled carbon nanotubes Stéphane Berciaud,a Laurent-walled carbon nanotubes (SWNTs) lead to heterogeneous samples containing mixtures of metallic and semiconducting species with a variety of lengths and defects. Optical detection at the single nanotube level should thus

Boyer, Edmond

495

Carbon nanotubes adhesion and nanomechanical behavior from peeling force spectroscopy  

E-Print Network [OSTI]

Carbon nanotubes adhesion and nanomechanical behavior from peeling force spectroscopy Julien December 17, 2010 Abstract Applications based on Single Walled Carbon Nanotube (SWNT) are good example such as adhesion energy per unit length, curvature and bending rigidity of the nanotube. A complete picture

Boyer, Edmond

496

Volcano remote sensing with ground-based spectroscopy  

Science Journals Connector (OSTI)

...background. At Popocatepetl volcano, Mexico, they observed a steady increase in SiF4...measurements of volcanic gas compositions by solar FTIR spectroscopy. Nature, 396, 567-570...eruption plume at Popocatepetl volcano, Mexico. Nature, 396, 563-567. doi:10...

2005-01-01T23:59:59.000Z

497

Single atom identification by energy dispersive x-ray spectroscopy  

SciTech Connect (OSTI)

Using aberration-corrected scanning transmission electron microscope and energy dispersive x-ray spectroscopy, single, isolated impurity atoms of silicon and platinum in monolayer and multilayer graphene are identified. Simultaneously acquired electron energy loss spectra confirm the elemental identification. Contamination difficulties are overcome by employing near-UHV sample conditions. Signal intensities agree within a factor of two with standardless estimates.

Lovejoy, T. C.; Dellby, N.; Krivanek, O. L. [Nion, 1102 8th St., Kirkland, Washington 98033 (United States); Ramasse, Q. M. [SuperSTEM Laboratory, STFC Daresbury, Keckwick Lane, Daresbury WA4 4AD (United Kingdom); Falke, M.; Kaeppel, A.; Terborg, R. [Bruker Nano GmbH, Schwarzschildstr. 12, 12489 Berlin (Germany); Zan, R. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)

2012-04-09T23:59:59.000Z