WorldWideScience

Sample records for energy loss spectroscopy

  1. electron energy-loss spectroscopy

    International Nuclear Information System (INIS)

    Egerton, R.

    1997-01-01

    As part of a commemorative series of articles to mark the hundredth anniversary of the discovery of the electron, this article describes the use of electron energy-loss spectroscopy. The physical and chemical properties of materials can be studied by considering the energy that electrons use as they travel through a solid, often in conjunction with other analytical techniques. The technique is often combined with electron diffraction and high-resolution imaging and can be used to provide elemental identification down to the atomic scale. 6 figs

  2. Electron energy-loss spectroscopy

    International Nuclear Information System (INIS)

    Egerton, R.

    1997-01-01

    As part of the commemorative series of articles to mark the hundredth anniversary of the discovery of the electron, this article discusses electron energy-loss spectroscopy. The physical and chemical properties of materials can be studied by considering the energy that electrons use as they travel through a solid, often in conjunction with other analytical techniques. The technique is often combined with electron diffraction and high-resolution imaging and can be used to provide elemental identification down to the atomic scale. (UK)

  3. Depth sectioning using electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    D'Alfonso, A J; Findlay, S D; Allen, L J; Cosgriff, E C; Kirkland, A I; Nellist, P D; Oxley, M P

    2008-01-01

    The continued development of electron probe aberration correctors for scanning transmission electron microscopy has enabled finer electron probes, allowing atomic resolution column-by-column electron energy loss spectroscopy. Finer electron probes have also led to a decrease in the probe depth of focus, facilitating optical slicing or depth sectioning of samples. The inclusion of post specimen aberration corrected image forming lenses allows for scanning confocal electron microscopy with further improved depth resolution and selectivity. We show that in both scanning transmission electron microscopy and scanning confocal electron microscopy geometries, by performing a three dimensional raster scan through a specimen and detecting electrons scattered with a characteristic energy loss, it will be possible to determine the location of isolated impurities embedded within the bulk.

  4. Energy loss spectroscopy applied to surface studies

    International Nuclear Information System (INIS)

    Lecante, J.

    1975-01-01

    The analysis of energy losses suffered by slow electrons (5eV to 300eV) back-scattered by single crystal surfaces appears to be a powerful method for surfaces studies. The inelastic scattering of these slow electrons limits their escape depth to the surface region. After a review of the basic excitation processes due to the interaction between electrons and surfaces (phonons, plasmons and electronic transitions) a brief discussion is given about the instruments needed for this electrons spectroscopy. Finally some experimental results are listed and it is shown that the comparison of the results given by ELS with other surface sensitive methods such as UPS is very fruitful and new information can be obtained. The improvement of theoretical studies on surface excitations due to slow electrons will provide in the next future the possibility of analysing in a more quantitative way the results given by ELS [fr

  5. Energy loss spectroscopy applied to surface studies

    International Nuclear Information System (INIS)

    Lecante, J.

    1975-01-01

    The analysis of energy losses suffered by slow electrons (5 eV to 300 eV) back-scattered by single crystal surfaces appears to be a powerful method for surfaces studies. The inelastic scattering of these slow electrons limits their escape depth to the surface region which is defined here. After a review of the basic excitation processes due to the interaction between electrons and surfaces (phonons, plasmons and electronic transitions) a brief discussion is given about the instruments needed for this electron spectroscopy. Finally some experimental results are listed and it is shown that the comparison of the results given by ELS with other surface sensitive methods such as UPS is very fruitful and new information can be obtained [fr

  6. The Generalized Multipole Technique for the Simulation of Low-Loss Electron Energy Loss Spectroscopy

    DEFF Research Database (Denmark)

    Kiewidt, Lars; Karamehmedovic, Mirza

    2018-01-01

    In this study, we demonstrate the use of a Generalized Multipole Technique (GMT) to simulate low-loss Electron Energy Loss Spectroscopy (EELS) spectra of isolated spheriodal nanoparticles. The GMT provides certain properties, such as semi-analytical description of the electromagnetic fields...

  7. Surface energy loss processes in XPS studied by absolute reflection electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Nagatomi, T.; Goto, K.

    2010-01-01

    The results of the investigation of the inelastic interaction of 300-3000 eV electrons with the Ni and Au surfaces by the analysis of absolute reflection electron energy loss spectroscopy (REELS) spectra were described. The present analysis enables the inelastic mean free path (IMFP), surface excitation parameter (SEP) and differential SEP (DSEP) to be obtained simultaneously from an absolute REELS spectrum. The obtained IMFPs for Ni and Au showed a good agreement with those calculated using the TPP-2M predictive equation. The present SEPs determined for Ni and Au were fitted to the Chen's formula describing the dependence of the SEP on the electron energy, and material parameters for Ni and Au in Chen's formula were proposed. The present DESPs were compared with the theoretical results, and a reasonable agreement between the experimentally determined DSEPs and theoretical results was confirmed. The MC modeling of calculating the REELS spectrum, in which energy loss processes due to surface excitations are taken into account, was also described. The IMFP, SEP and DSEP determined by the present absolute REELS analysis were employed to describe energy loss processes by inelastic scattering in the proposed MC simulation. The simulated REELS spectra were found to be in a good agreement with the experimental spectra for both Ni and Au.

  8. Probing Plasmonic Nanostructures with Electron Energy - Loss Spectroscopy

    DEFF Research Database (Denmark)

    Raza, Søren

    for nonlocal response. The experimental work comprises the use of electron energy-loss spectroscopy (EELS) to excite and study both localized and propagating surface plasmons in metal structures. Following a short introduction, we present the theoretical foundation to describe nonlocal response in Maxwell......, dimer with nanometer-sized gaps, core-shell nanowire with ultrathin metal shell, and a thin metal film. In all cases we compare the nonlocal models with the local-response approximation. Below the plasma frequency, we find that the distance between the induced positive and negative surface charges...

  9. Electron energy loss spectroscopy of gold nanoparticles on graphene

    International Nuclear Information System (INIS)

    DeJarnette, Drew; Roper, D. Keith

    2014-01-01

    Plasmon excitation decay by absorption, scattering, and hot electron transfer has been distinguished from effects induced by incident photons for gold nanoparticles on graphene monolayer using electron energy loss spectroscopy (EELS). Gold nano-ellipses were evaporated onto lithographed graphene, which was transferred onto a silicon nitride transmission electron microscopy grid. Plasmon decay from lithographed nanoparticles measured with EELS was compared in the absence and presence of the graphene monolayer. Measured decay values compared favorably with estimated radiative and non-radiative contributions to decay in the absence of graphene. Graphene significantly enhanced low-energy plasmon decay, increasing mode width 38%, but did not affect higher energy plasmon or dark mode decay. This decay beyond expected radiative and non-radiative mechanisms was attributed to hot electron transfer, and had quantum efficiency of 20%, consistent with previous reports

  10. Atomic column resolved electron energy-loss spectroscopy

    International Nuclear Information System (INIS)

    Duscher, G.; Pennycook, S.J.; Browning, N.D.

    1998-01-01

    Spatially resolved electron energy-loss spectroscopy (EELS) is rapidly developing into a unique and powerful tool to characterize internal interfaces. Because atomic column resolved Z-contrast imaging can be performed simultaneously with EELS in the scanning transmission electron microscope, this combination allows the atomic structure to be correlated with the electronic structure, and thus the local properties of interfaces or defects can be determined directly. However, the ability to characterize interfaces and defects at that level requires not only high spatial resolution but also the exact knowledge of the beam location, from where the spectrum is obtained. Here we discuss several examples progressing from cases where the limitation in spatial resolution is given by the microscopes or the nature of the sample, to one example of impurity atoms at a grain boundary, which show intensity and fine structure changes from atomic column to atomic column. Such data can be interpreted as changes in valence of the impurity, depending on its exact site in the boundary plane. Analysis ofthis nature is a valuable first step in understanding the microscopic structural, optical and electronic properties of materials. (orig.)

  11. Electron energy-loss spectroscopy on fullerenes and fullerene compounds

    International Nuclear Information System (INIS)

    Armbruster, J.

    1996-03-01

    A few years ago, a new form of pure carbon, the fullerenes, has been discovered, which shows many fascinating properties. Within this work the spatial and electronic structure of some selected fullerene compounds have been investigated by electron-energy-loss spectroscopy in transmission. Phase pure samples of alkali intercalated fullerides A x C 60 (A=Na, K, Cs) have been prepared using vacuum distillation. Measruements of K 3 C 60 show a dispersion of the charge carrier plasmon close to zero. This can be explained by calculations, which take into account both band structure and local-field (inhomogeneity) effects. The importance of the molecular structure can also be seen from the A 4 C 60 compounds, where the non-metallic properties are explained by a splitting of the t 1u and t 1g derived bands that is caused by electron-correlation and Jahn-Teller effects. First measurements of the electronic structure of Na x C 60 (x>6) are presented and reveal a complete transfer from the sodium atoms but an incomplete transfer onto the C 60 molecules. This behaviour can be explained by taking into account additional electronic states that are situated between the sodium atoms in the octahedral sites and are predicted by calculations using local density approximation. The crystal structure of the higher fullerenes C 76 and C 84 is found to be face-centered cubic

  12. Microanalysis by spectroscopy of transmitted electron energy losses

    International Nuclear Information System (INIS)

    Colliex, C.; Trebbia, P.

    1978-01-01

    Among the various signals which, in a transmission electron microscope, result from the interactions between the primary beam of well defined energy E 0 and the sample, the spectrum of the energy distribution of the electrons transmitted contains useful informations on the chemical and physical properties of the sample. Consequently the adaptation of an energy dispersive system on an electron microscope enables new fields of research to be investigated, particularly a localised chemical analysis technique with a space resolution scale equal to that of the electron microscope. It is this second aspect that we suggest describing in particular here. Already, this technique appears to be indispensable in the problems arising from the analysis of very small quantities of matter: detection limits in the order of 10 -19 to 10 -20 g (around 100 to 1000 atoms) would seem to be resonably possible [fr

  13. Optimization of Monochromated TEM for Ultimate Resolution Imaging and Ultrahigh Resolution Electron Energy Loss Spectroscopy

    KAUST Repository

    Lopatin, Sergei; Cheng, Bin; Liu, Wei-Ting; Tsai, Meng-Lin; He, Jr-Hau; Chuvilin, Andrey

    2017-01-01

    The performance of a monochromated transmission electron microscope with Wien type monochromator is optimized to achieve an extremely narrow energy spread of electron beam and an ultrahigh energy resolution with spectroscopy. The energy spread in the beam is improved by almost an order of magnitude as compared to specified values. The optimization involves both the monochromator and the electron energy loss detection system. We demonstrate boosted capability of optimized systems with respect to ultra-low loss EELS and sub-angstrom resolution imaging (in a combination with spherical aberration correction).

  14. Optimization of Monochromated TEM for Ultimate Resolution Imaging and Ultrahigh Resolution Electron Energy Loss Spectroscopy

    KAUST Repository

    Lopatin, Sergei

    2017-09-01

    The performance of a monochromated transmission electron microscope with Wien type monochromator is optimized to achieve an extremely narrow energy spread of electron beam and an ultrahigh energy resolution with spectroscopy. The energy spread in the beam is improved by almost an order of magnitude as compared to specified values. The optimization involves both the monochromator and the electron energy loss detection system. We demonstrate boosted capability of optimized systems with respect to ultra-low loss EELS and sub-angstrom resolution imaging (in a combination with spherical aberration correction).

  15. Quantification of the boron speciation in alkali borosilicate glasses by electron energy loss spectroscopy

    DEFF Research Database (Denmark)

    Cheng, D.S.; Yang, G.; Zhao, Y.Q.

    2015-01-01

    developed a method based on electron energy loss spectroscopy (EELS) data acquisition and analyses, which enables determination of the boron speciation in a series of ternary alkali borosilicate glasses with constant molar ratios. A script for the fast acquisition of EELS has been designed, from which...

  16. Vacuum ultra-violet and electron energy loss spectroscopy of gaseous and solid organic compounds

    International Nuclear Information System (INIS)

    Koch, E.E.; Otto, A.

    1976-01-01

    The experimental arrangements used by the authors for the study of optical vacuum ultra-violet and electron energy loss spectra of organic compounds are described and some theoretical aspects of studies of higher excited states are considered. Results for alkanes, benzene, naphthalene, anthracene and some more complex hydrocarbons are reviewed. Recent results obtained by reflection and electron energy loss spectroscopy for single crystals of anthracene are included and their relevance for gas phase work as well as for the understanding of exciton effects in organic solids is described. (author)

  17. First-Principles Vibrational Electron Energy Loss Spectroscopy of β -Guanine

    Science.gov (United States)

    Radtke, G.; Taverna, D.; Lazzeri, M.; Balan, E.

    2017-07-01

    A general approach to model vibrational electron energy loss spectra obtained using an electron beam positioned away from the specimen is presented. The energy-loss probability of the fast electron is evaluated using first-principles quantum mechanical calculations (density functional theory) of the dielectric response of the specimen. The validity of the method is assessed using recently measured anhydrous β -guanine, an important molecular solid used by animals to produce structural colors. The good agreement between theory and experiments lays the basis for a quantitative interpretation of this spectroscopy in complex systems.

  18. Depth-selective X-ray absorption spectroscopy by detection of energy-loss Auger electrons

    Energy Technology Data Exchange (ETDEWEB)

    Isomura, Noritake, E-mail: isomura@mosk.tytlabs.co.jp [Toyota Central R& D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan); Soejima, Narumasa; Iwasaki, Shiro [Toyota Central R& D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan); Nomoto, Toyokazu; Murai, Takaaki [Aichi Synchrotron Radiation Center (AichiSR), 250-3 Minamiyamaguchi-cho, Seto, Aichi 489-0965 (Japan); Kimoto, Yasuji [Toyota Central R& D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan)

    2015-11-15

    Graphical abstract: - Highlights: • A unique XAS method is proposed for depth profiling of chemical states. • PEY mode detecting energy-loss electrons enables a variation in the probe depth. • Si K-edge XAS spectra of the Si{sub 3}N{sub 4}/SiO{sub 2}/Si multilayer films have been investigated. • Deeper information was obtained in the spectra measured at larger energy loss. • Probe depth could be changed by the selection of the energy of detected electrons. - Abstract: A unique X-ray absorption spectroscopy (XAS) method is proposed for depth profiling of chemical states in material surfaces. Partial electron yield mode detecting energy-loss Auger electrons, called the inelastic electron yield (IEY) mode, enables a variation in the probe depth. As an example, Si K-edge XAS spectra for a well-defined multilayer sample (Si{sub 3}N{sub 4}/SiO{sub 2}/Si) have been investigated using this method at various kinetic energies. We found that the peaks assigned to the layers from the top layer to the substrate appeared in the spectra in the order of increasing energy loss relative to the Auger electrons. Thus, the probe depth can be changed by the selection of the kinetic energy of the energy loss electrons in IEY-XAS.

  19. Depth-selective X-ray absorption spectroscopy by detection of energy-loss Auger electrons

    International Nuclear Information System (INIS)

    Isomura, Noritake; Soejima, Narumasa; Iwasaki, Shiro; Nomoto, Toyokazu; Murai, Takaaki; Kimoto, Yasuji

    2015-01-01

    Graphical abstract: - Highlights: • A unique XAS method is proposed for depth profiling of chemical states. • PEY mode detecting energy-loss electrons enables a variation in the probe depth. • Si K-edge XAS spectra of the Si_3N_4/SiO_2/Si multilayer films have been investigated. • Deeper information was obtained in the spectra measured at larger energy loss. • Probe depth could be changed by the selection of the energy of detected electrons. - Abstract: A unique X-ray absorption spectroscopy (XAS) method is proposed for depth profiling of chemical states in material surfaces. Partial electron yield mode detecting energy-loss Auger electrons, called the inelastic electron yield (IEY) mode, enables a variation in the probe depth. As an example, Si K-edge XAS spectra for a well-defined multilayer sample (Si_3N_4/SiO_2/Si) have been investigated using this method at various kinetic energies. We found that the peaks assigned to the layers from the top layer to the substrate appeared in the spectra in the order of increasing energy loss relative to the Auger electrons. Thus, the probe depth can be changed by the selection of the kinetic energy of the energy loss electrons in IEY-XAS.

  20. High-resolution monochromated electron energy-loss spectroscopy of organic photovoltaic materials.

    Science.gov (United States)

    Alexander, Jessica A; Scheltens, Frank J; Drummy, Lawrence F; Durstock, Michael F; Hage, Fredrik S; Ramasse, Quentin M; McComb, David W

    2017-09-01

    Advances in electron monochromator technology are providing opportunities for high energy resolution (10 - 200meV) electron energy-loss spectroscopy (EELS) to be performed in the scanning transmission electron microscope (STEM). The energy-loss near-edge structure in core-loss spectroscopy is often limited by core-hole lifetimes rather than the energy spread of the incident illumination. However, in the valence-loss region, the reduced width of the zero loss peak makes it possible to resolve clearly and unambiguously spectral features at very low energy-losses (photovoltaics (OPVs): poly(3-hexlythiophene) (P3HT), [6,6] phenyl-C 61 butyric acid methyl ester (PCBM), copper phthalocyanine (CuPc), and fullerene (C 60 ). Data was collected on two different monochromated instruments - a Nion UltraSTEM 100 MC 'HERMES' and a FEI Titan 3 60-300 Image-Corrected S/TEM - using energy resolutions (as defined by the zero loss peak full-width at half-maximum) of 35meV and 175meV, respectively. The data was acquired to allow deconvolution of plural scattering, and Kramers-Kronig analysis was utilized to extract the complex dielectric functions. The real and imaginary parts of the complex dielectric functions obtained from the two instruments were compared to evaluate if the enhanced resolution in the Nion provides new opto-electronic information for these organic materials. The differences between the spectra are discussed, and the implications for STEM-EELS studies of advanced materials are considered. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Measurement of the band gap by reflection electron energy loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Vos, Maarten, E-mail: maarten.vos@anu.edu.au [Electronic Materials Engineering Department, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); King, Sean W. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States); French, Benjamin L. [Ocotillo Materials Laboratory, Intel Corporation, Chandler, AZ 85248 (United States)

    2016-10-15

    Highlights: • Semiconductors are measured (without surface preparation) using REELS. • At low beam energies it is difficult to measure band gap due to surface impurities. • At very high energies it is difficult to measure band gap due to recoil effect. • At intermediate energies (around 5 keV) one obtains a good estimate of the band gap. - Abstract: We investigate the possibilities of measuring the band gap of a variety of semiconductors and insulators by reflection electron energy loss spectroscopy without additional surface preparation. The band gap is a bulk property, whereas reflection energy loss spectroscopy is generally considered a surface sensitive technique. By changing the energy of the incoming electrons, the degree of surface sensitivity can be varied. Here, we present case studies to determine the optimum condition for the determination of the band gap. At very large incoming electron energies recoil effects interfere with the band gap determination, whereas at very low energies surface effects are obscuring the band gap without surface preparation. Using an incoming energy of 5 keV a reasonable estimate of the band gap is obtained in most cases.

  2. Measurement of the band gap by reflection electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Vos, Maarten; King, Sean W.; French, Benjamin L.

    2016-01-01

    Highlights: • Semiconductors are measured (without surface preparation) using REELS. • At low beam energies it is difficult to measure band gap due to surface impurities. • At very high energies it is difficult to measure band gap due to recoil effect. • At intermediate energies (around 5 keV) one obtains a good estimate of the band gap. - Abstract: We investigate the possibilities of measuring the band gap of a variety of semiconductors and insulators by reflection electron energy loss spectroscopy without additional surface preparation. The band gap is a bulk property, whereas reflection energy loss spectroscopy is generally considered a surface sensitive technique. By changing the energy of the incoming electrons, the degree of surface sensitivity can be varied. Here, we present case studies to determine the optimum condition for the determination of the band gap. At very large incoming electron energies recoil effects interfere with the band gap determination, whereas at very low energies surface effects are obscuring the band gap without surface preparation. Using an incoming energy of 5 keV a reasonable estimate of the band gap is obtained in most cases.

  3. A proximal retarding field analyzer for scanning probe energy loss spectroscopy

    Science.gov (United States)

    Bauer, Karl; Murphy, Shane; Palmer, Richard E.

    2017-03-01

    A compact proximal retarding field analyzer for scanning probe energy loss spectroscopy measurements is described. Using the scanning tunneling microscope (STM) tip as a field emission (FE) electron source in conjunction with this analyzer, which is placed at a glancing angle to the surface plane, FE sample current and electron reflectivity imaging may be performed simultaneously. This is demonstrated in measurements of Ag nanostructures prepared on graphite by electron-beam lithography, where a material contrast of 13% is observed, with a lateral resolution of 25 nm, between the silver and graphite in electron reflectivity images. Topological contrast mechanisms such as edge enhancement and shadowing are also observed, giving rise to additional features in the electron reflectivity images. The same instrument configuration has been used to measure electron energy loss spectra on bare graphite, where the zero loss peak, π band plasmon loss peak and secondary electron peaks are observed. Using this simple and compact analyzer an STM, with sufficient open access to the tip-sample junction, may easily be augmented to provide simultaneous elemental and topographic mapping, supplementing STM image measurements with FE sample current and electron reflectivity images, as well as electron energy loss spectroscopy measurements, in the same instrument.

  4. Electron energy-loss spectroscopy of quasi-one-dimensional cuprates and vanadates

    International Nuclear Information System (INIS)

    Atzkern, S.

    2001-01-01

    In a combination of experimental and theoretical methods in this thesis the electronic structures of quasi-one-dimensional cuprates and vanadates were studied. For this the momentum-dependent loss function was measured by means of the electron energy-loss spectroscopy in transmission on monocrystals of Li 2 CuO 2 , CuGeO 3 , V 2 O 5 and α'-NaVO 5 . The comparison of the experimental data with results from band-structure and cluster calculations allowed conclusions on the mobility and correlations of the electrons in these systems

  5. Precessed electron beam electron energy loss spectroscopy of graphene: Beyond channelling effects

    Energy Technology Data Exchange (ETDEWEB)

    Yedra, Ll.; Estradé, S., E-mail: sestrade@ub.edu [LENS, MIND-IN2UB, Departament d' Electrònica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); TEM-MAT, CCiT, Universitat de Barcelona, Solé i Sabarís 1, 08028 Barcelona (Spain); Torruella, P.; Eljarrat, A.; Peiró, F. [LENS, MIND-IN2UB, Departament d' Electrònica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Darbal, A. D. [AppFive LLC, 1095 W Rio Salado Pkway, Suite 110, Tempe, Arizona 85281 (United States); Weiss, J. K. [AppFive LLC, 1095 W Rio Salado Pkway, Suite 110, Tempe, Arizona 85281 (United States); NanoMEGAS SPRL, Blvd. Edmond Machtens 79, B-1080 Brussels (Belgium)

    2014-08-04

    The effects of beam precession on the Electron Energy Loss Spectroscopy (EELS) signal of the carbon K edge in a 2 monolayer graphene sheet are studied. In a previous work, we demonstrated the use of precession to compensate for the channeling-induced reduction of EELS signal when in zone axis. In the case of graphene, no enhancement of EELS signal is found in the usual experimental conditions, as graphene is not thick enough to present channeling effects. Interestingly, though it is found that precession makes it possible to increase the collection angle, and, thus, the overall signal, without a loss of signal-to-background ratio.

  6. Electron Energy-Loss Spectroscopy: Fundamentals and applications in the characterization of minerals

    International Nuclear Information System (INIS)

    Krishnan, K.M.

    1989-04-01

    The combined use of an energy-loss spectrometer and an analytical electron microscope with fine probe forming capabilities provides a wealth of information about the sample at high spatial resolution. Fundamental principles governing the physics of the interaction between the fast electron and a thin foil sample, to account for the fine structure in the inelastically scattered fast electron distribution (Electron-Energy Loss Spectroscopy, EELS), will be reviewed. General application of EELS is in the area of low atomic number elements (Z < 11) microanalysis, where it significantly complements the more widely used Energy Dispersive X-ray Spectroscopy (EDXS). However, a careful analysis of the low loss plasmon oscillations and the fine structure in the core-loss edges, can provide additional information related to the bonding and electronic structure of the sample. An illustration of this is presented from our study of Cδ diamond residue from the Allende carbonaceous chondrite. Combination of EELS with channeling effects can provide specific site occupation/valence information in crystalline materials. Details of this novel crystallographic method will be outlined and illustrated with an example of the study of chromite spinels. Finally, some pertinent experimental details will be discussed. 7 figs

  7. Some thoughts on source monochromation and the implications for electron energy loss spectroscopy

    CERN Document Server

    Brydson, R; Brown, A

    2003-01-01

    We briefly outline the factors determining the intrinsic widths of features in electron energy loss near edge structure (ELNES) measured by electron energy loss spectroscopy (EELS) in the transmission electron microscope (TEM). We have made estimates of the differing contributions of both the initial and final state lifetime effects in the ELNES ionisation processes and also show how these may be combined with the instrumental energy resolution. We discuss the potential benefits of source monochromation for ELNES measurements via a comparison of these theoretical estimates with experimental spectra from the literature. We show that for certain core level excitations, solid state broadening mechanisms may be the fundamental limiting factor for resolving fine detail in ELNES. (orig.)

  8. Communication: Investigation of the electron momentum density distribution of nanodiamonds by electron energy-loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Zhenbao; Yang, Bing; Lin, Yangming; Su, Dangsheng, E-mail: dssu@imr.ac.cn [Shenyang National Laboratory of Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016 (China)

    2015-12-07

    The electron momentum distribution of detonation nanodiamonds (DND) was investigated by recording electron energy-loss spectra at large momentum transfer in the transmission electron microscope (TEM), which is known as electron Compton scattering from solid (ECOSS). Compton profile of diamond film obtained by ECOSS was found in good agreement with prior photon experimental measurement and theoretical calculation that for bulk diamond. Compared to the diamond film, the valence Compton profile of DND was found to be narrower, which indicates a more delocalization of the ground-state charge density for the latter. Combining with other TEM characterizations such as high-resolution transmission electron spectroscopy, diffraction, and energy dispersive X-ray spectroscopy measurements, ECOSS was shown to be a great potential technique to study ground-state electronic properties of nanomaterials.

  9. Multivariate statistical analysis of electron energy-loss spectroscopy in anisotropic materials

    International Nuclear Information System (INIS)

    Hu Xuerang; Sun Yuekui; Yuan Jun

    2008-01-01

    Recently, an expression has been developed to take into account the complex dependence of the fine structure in core-level electron energy-loss spectroscopy (EELS) in anisotropic materials on specimen orientation and spectral collection conditions [Y. Sun, J. Yuan, Phys. Rev. B 71 (2005) 125109]. One application of this expression is the development of a phenomenological theory of magic-angle electron energy-loss spectroscopy (MAEELS), which can be used to extract the isotropically averaged spectral information for materials with arbitrary anisotropy. Here we use this expression to extract not only the isotropically averaged spectral information, but also the anisotropic spectral components, without the restriction of MAEELS. The application is based on a multivariate statistical analysis of core-level EELS for anisotropic materials. To demonstrate the applicability of this approach, we have conducted a study on a set of carbon K-edge spectra of multi-wall carbon nanotube (MWCNT) acquired with energy-loss spectroscopic profiling (ELSP) technique and successfully extracted both the averaged and dichroic spectral components of the wrapped graphite-like sheets. Our result shows that this can be a practical alternative to MAEELS for the study of electronic structure of anisotropic materials, in particular for those nanostructures made of layered materials

  10. Investigation of Deuterium Implantation into Beryllium Sample by Electron Energy Loss Spectroscopy

    Science.gov (United States)

    Afanas'ev, V. P.; Gryazev, A. S.; Kaplya, P. S.; Köppen, M.; Ridzel, O. Yu; Subbotin, N. Yu; Hansen, P.

    2017-11-01

    Quantitative analysis of hydrogen isotopes in first wall as well as in construction materials of future fusion devices plays a crucial role to understand the evolution of those materials under operation conditions. A quantitative understanding of hydrogen in materials is also an important issue for storing energy as well as for fuel cells. A combination of Electron Energy Loss Spectroscopy (EELS) and Elastic Peak Electron Spectroscopy (EPES) is presented in this study to tackle these problems of modern material research for energy production and storage. Accurate inelastic scattering background subtraction is a key part of the presented quantitative measurement of the Be/D ratio. The differential inelastic scattering cross-section is determined by the fitting procedure. The fitting procedure is based on the iterative solution of the direct problem and minimization of the residual between computed and measured spectra. This study also takes into account the difference in electron energy loss laws for surface and bulk. The inelastic scattering cross-sections for different doses of deuterium ions in beryllium substrate (5.5·1021 m-2 and 2.01·1022 m-2) were defined in a two-layered model. The analysis is carried out for the EELS spectra. Relative concentration of D atoms is defined.

  11. Analytical modeling of electron energy loss spectroscopy of graphene: Ab initio study versus extended hydrodynamic model.

    Science.gov (United States)

    Djordjević, Tijana; Radović, Ivan; Despoja, Vito; Lyon, Keenan; Borka, Duško; Mišković, Zoran L

    2018-01-01

    We present an analytical modeling of the electron energy loss (EEL) spectroscopy data for free-standing graphene obtained by scanning transmission electron microscope. The probability density for energy loss of fast electrons traversing graphene under normal incidence is evaluated using an optical approximation based on the conductivity of graphene given in the local, i.e., frequency-dependent form derived by both a two-dimensional, two-fluid extended hydrodynamic (eHD) model and an ab initio method. We compare the results for the real and imaginary parts of the optical conductivity in graphene obtained by these two methods. The calculated probability density is directly compared with the EEL spectra from three independent experiments and we find very good agreement, especially in the case of the eHD model. Furthermore, we point out that the subtraction of the zero-loss peak from the experimental EEL spectra has a strong influence on the analytical model for the EEL spectroscopy data. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Application of electron energy loss spectroscopy for single wall carbon nanotubes (review)

    International Nuclear Information System (INIS)

    Mittal, N.; Jain, S.; Mittal, J.

    2015-01-01

    Electron energy loss spectroscopy (EELS) is among the few techniques that are available for the characterization of modified single wall carbon nanotubes (SWCNTs) having nanometer dimensions (~1-3 nm). CNTs can be modified either by surface functionalization or coating, between bundles of nanotubes by doping, intercalation and fully or partially filling the central core. EELS is an exclusive technique for the identification, composition analysis, and crystallization studies of the chemicals and materials used for the modification of SWCNTs. The present paper serves as a compendium of research work on the application of EELS for the characterization of modified SWCNTs. (authors)

  13. Electron energy-loss spectroscopy study of NiTi shape memory alloys

    International Nuclear Information System (INIS)

    Yang, Z.Q.; Schryvers, D.

    2008-01-01

    Electron energy loss spectroscopy (EELS) investigations were carried out on NiTi shape memory alloys. The composition of lens-shaped precipitates is determined to be Ni 4 Ti 3 by model-based EELS quantification, and the Ni-depleted zone in the B2 matrix surrounding the Ni 4 Ti 3 precipitates was quantified. The Young's modulus Y m of the B2 matrix with 51 at.% Ni and the Ni 4 Ti 3 precipitates was evaluated to be about 124 and 175 GPa, respectively. The intensity of the Ni L 3 edge for the precipitate is slightly higher than that for the B2 phase

  14. Nanoscale probing of bandgap states on oxide particles using electron energy-loss spectroscopy.

    Science.gov (United States)

    Liu, Qianlang; March, Katia; Crozier, Peter A

    2017-07-01

    Surface and near-surface electronic states were probed with nanometer spatial resolution in MgO and TiO 2 anatase nanoparticles using ultra-high energy resolution electron energy-loss spectroscopy (EELS) coupled to a scanning transmission electron microscope (STEM). This combination allows the surface electronic structure determined with spectroscopy to be correlated with nanoparticle size, morphology, facet etc. By acquiring the spectra in aloof beam mode, radiation damage to the surface can be significantly reduced while maintaining the nanometer spatial resolution. MgO and TiO 2 showed very different bandgap features associated with the surface/sub-surface layer of the nanoparticles. Spectral simulations based on dielectric theory and density of states models showed that a plateau feature found in the pre-bandgap region in the spectra from (100) surfaces of 60nm MgO nanocubes is consistent with a thin hydroxide surface layer. The spectroscopy shows that this hydroxide species gives rise to a broad filled surface state at 1.1eV above the MgO valence band. At the surfaces of TiO 2 nanoparticles, pronounced peaks were observed in the bandgap region, which could not be well fitted to defect states. In this case, the high refractive index and large particle size may make Cherenkov or guided light modes the likely causes of the peaks. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Mapping bright and dark modes in gold nanoparticle chains using electron energy loss spectroscopy.

    Science.gov (United States)

    Barrow, Steven J; Rossouw, David; Funston, Alison M; Botton, Gianluigi A; Mulvaney, Paul

    2014-07-09

    We present a scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) investigation of gold nanosphere chains with lengths varying from 1 to 5 particles. We show localized EELS signals from the chains and identify energy-loss peaks arising due to l = 1, 2, 3, 4, and 5 plasmon modes through the use of EELS mapping. We also show the evolution of the energy of these modes as the length of a given chain increases, and we find that a chain containing N particles can accommodate at least N experimentally observable modes, in addition to the transverse mode. As the chain length is increased by the addition of one more gold particle to the chain, the new N + 1 mode becomes the highest energy mode, while the existing modes lower their energy and eventually asymptote as they delocalize along the chain. We also show that modes become increasingly difficult to detect with the EELS technique as l approaches N. The data are compared to numerical simulations.

  16. Electron energy loss spectroscopy of excitons in two-dimensional-semiconductors as a function of temperature

    KAUST Repository

    Tizei, Luiz H. G.; Lin, Yung-Chang; Lu, Ang-Yd; Li, Lain-Jong; Suenaga, Kazu

    2016-01-01

    We have explored the benefits of performing monochromated Electron Energy Loss Spectroscopy(EELS) in samples at cryogenic temperatures. As an example, we have observed the excitonic absorption peaks in single layer Transition Metal Dichalcogenides. These peaks appear separated by small energies due to spin orbit coupling. We have been able to distinguish the split for MoS2 below 300 K and for MoSe2 below 220 K. However, the distinction between peaks is only clear at 150 K. We have measured the change in absorption threshold between 150 K and 770 K for MoS2 and MoSe2. We discuss the effect of carbon and ice contamination in EELSspectra. The increased spectral resolution available made possible with modern monochromators in electron microscopes will require the development of stable sample holders which reaches temperatures far below that of liquid nitrogen.

  17. Electron energy loss spectroscopy of excitons in two-dimensional-semiconductors as a function of temperature

    KAUST Repository

    Tizei, Luiz H. G.

    2016-04-21

    We have explored the benefits of performing monochromated Electron Energy Loss Spectroscopy(EELS) in samples at cryogenic temperatures. As an example, we have observed the excitonic absorption peaks in single layer Transition Metal Dichalcogenides. These peaks appear separated by small energies due to spin orbit coupling. We have been able to distinguish the split for MoS2 below 300 K and for MoSe2 below 220 K. However, the distinction between peaks is only clear at 150 K. We have measured the change in absorption threshold between 150 K and 770 K for MoS2 and MoSe2. We discuss the effect of carbon and ice contamination in EELSspectra. The increased spectral resolution available made possible with modern monochromators in electron microscopes will require the development of stable sample holders which reaches temperatures far below that of liquid nitrogen.

  18. Energy loss spectroscopy study of Si(111)--alkali metal interfaces at low temperatures

    International Nuclear Information System (INIS)

    Avci, R.

    1986-01-01

    Studies are made at approx.150 K under ultrahigh vacuum conditions on a wide range of alkali metal coverages on Si(111)-7 x 7. Negative second-derivative backscattered electron energy loss spectroscopy is used with 100 eV primary electrons. The interaction of the alkali metals with the silicon substrate goes through two stages as a function of alkali coverage: In the initial coverages, for less than approx.0.3 monolayer of alkali atoms, the basic reaction is that of charge transfer from the alkali atoms to the Si surface with a loss peak at approx.3.3 eV associated with the charge transfer states. The second stage of reaction: starting after the depletion of all the Si surface states: falls in a coverage range between approx.0.3 and approx.1 monolayer, in which the formation of a metallic layer with a coverage-dependent loss feature at about 2 eV is observed. At still higher coverages, multiple surface and bulk plasmon excitations and their combinations are dominant. In the overall scattering processes most of the parallel momentum (approx.3 A -1 ) is transferred to the sample during the elastic backscattering from the surface, and all the losses are essentially attributed to the forward inelastic scattering before and/or after the elastic process takes place near the metal/Si interface

  19. Low-dose electron energy-loss spectroscopy using electron counting direct detectors.

    Science.gov (United States)

    Maigné, Alan; Wolf, Matthias

    2018-03-01

    Since the development of parallel electron energy loss spectroscopy (EELS), charge-coupled devices (CCDs) have been the default detectors for EELS. With the recent development of electron-counting direct-detection cameras, micrographs can be acquired under very low electron doses at significantly improved signal-to-noise ratio. In spectroscopy, in particular in combination with a monochromator, the signal can be extremely weak and the detection limit is principally defined by noise introduced by the detector. Here we report the use of an electron-counting direct-detection camera for EEL spectroscopy. We studied the oxygen K edge of amorphous ice and obtained a signal noise ratio up to 10 times higher than with a conventional CCD.We report the application of electron counting to record time-resolved EEL spectra of a biological protein embedded in amorphous ice, revealing chemical changes observed in situ while exposed by the electron beam. A change in the fine structure of nitrogen K and the carbon K edges were recorded during irradiation. A concentration of 3 at% nitrogen was detected with a total electron dose of only 1.7 e-/Å2, extending the boundaries of EELS signal detection at low electron doses.

  20. Electron Energy Loss Spectroscopy imaging of surface plasmons at the nanometer scale

    Energy Technology Data Exchange (ETDEWEB)

    Colliex, Christian, E-mail: christian.colliex@u-psud.fr; Kociak, Mathieu; Stéphan, Odile

    2016-03-15

    Since their first realization, electron microscopes have demonstrated their unique ability to map with highest spatial resolution (sub-atomic in most recent instruments) the position of atoms as a consequence of the strong scattering of the incident high energy electrons by the nuclei of the material under investigation. When interacting with the electron clouds either on atomic orbitals or delocalized over the specimen, the associated energy transfer, measured and analyzed as an energy loss (Electron Energy Loss Spectroscopy) gives access to analytical properties (atom identification, electron states symmetry and localization). In the moderate energy-loss domain (corresponding to an optical spectral domain from the infrared (IR) to the rather far ultra violet (UV), EELS spectra exhibit characteristic collective excitations of the rather-free electron gas, known as plasmons. Boundary conditions, such as surfaces and/or interfaces between metallic and dielectric media, generate localized surface charge oscillations, surface plasmons (SP), which are associated with confined electric fields. This domain of research has been extraordinarily revived over the past few years as a consequence of the burst of interest for structures and devices guiding, enhancing and controlling light at the sub-wavelength scale. The present review focuses on the study of these surface plasmons with an electron microscopy-based approach which associates spectroscopy and mapping at the level of a single and well-defined nano-object, typically at the nanometer scale i.e. much improved with respect to standard, and even near-field, optical techniques. After calling to mind some early studies, we will briefly mention a few basic aspects of the required instrumentation and associated theoretical tools to interpret the very rich data sets recorded with the latest generation of (Scanning)TEM microscopes. The following paragraphs will review in more detail the results obtained on simple planar and

  1. Electron Energy Loss Spectroscopy imaging of surface plasmons at the nanometer scale.

    Science.gov (United States)

    Colliex, Christian; Kociak, Mathieu; Stéphan, Odile

    2016-03-01

    Since their first realization, electron microscopes have demonstrated their unique ability to map with highest spatial resolution (sub-atomic in most recent instruments) the position of atoms as a consequence of the strong scattering of the incident high energy electrons by the nuclei of the material under investigation. When interacting with the electron clouds either on atomic orbitals or delocalized over the specimen, the associated energy transfer, measured and analyzed as an energy loss (Electron Energy Loss Spectroscopy) gives access to analytical properties (atom identification, electron states symmetry and localization). In the moderate energy-loss domain (corresponding to an optical spectral domain from the infrared (IR) to the rather far ultra violet (UV), EELS spectra exhibit characteristic collective excitations of the rather-free electron gas, known as plasmons. Boundary conditions, such as surfaces and/or interfaces between metallic and dielectric media, generate localized surface charge oscillations, surface plasmons (SP), which are associated with confined electric fields. This domain of research has been extraordinarily revived over the past few years as a consequence of the burst of interest for structures and devices guiding, enhancing and controlling light at the sub-wavelength scale. The present review focuses on the study of these surface plasmons with an electron microscopy-based approach which associates spectroscopy and mapping at the level of a single and well-defined nano-object, typically at the nanometer scale i.e. much improved with respect to standard, and even near-field, optical techniques. After calling to mind some early studies, we will briefly mention a few basic aspects of the required instrumentation and associated theoretical tools to interpret the very rich data sets recorded with the latest generation of (Scanning)TEM microscopes. The following paragraphs will review in more detail the results obtained on simple planar and

  2. Electron Energy Loss Spectroscopy imaging of surface plasmons at the nanometer scale

    International Nuclear Information System (INIS)

    Colliex, Christian; Kociak, Mathieu; Stéphan, Odile

    2016-01-01

    Since their first realization, electron microscopes have demonstrated their unique ability to map with highest spatial resolution (sub-atomic in most recent instruments) the position of atoms as a consequence of the strong scattering of the incident high energy electrons by the nuclei of the material under investigation. When interacting with the electron clouds either on atomic orbitals or delocalized over the specimen, the associated energy transfer, measured and analyzed as an energy loss (Electron Energy Loss Spectroscopy) gives access to analytical properties (atom identification, electron states symmetry and localization). In the moderate energy-loss domain (corresponding to an optical spectral domain from the infrared (IR) to the rather far ultra violet (UV), EELS spectra exhibit characteristic collective excitations of the rather-free electron gas, known as plasmons. Boundary conditions, such as surfaces and/or interfaces between metallic and dielectric media, generate localized surface charge oscillations, surface plasmons (SP), which are associated with confined electric fields. This domain of research has been extraordinarily revived over the past few years as a consequence of the burst of interest for structures and devices guiding, enhancing and controlling light at the sub-wavelength scale. The present review focuses on the study of these surface plasmons with an electron microscopy-based approach which associates spectroscopy and mapping at the level of a single and well-defined nano-object, typically at the nanometer scale i.e. much improved with respect to standard, and even near-field, optical techniques. After calling to mind some early studies, we will briefly mention a few basic aspects of the required instrumentation and associated theoretical tools to interpret the very rich data sets recorded with the latest generation of (Scanning)TEM microscopes. The following paragraphs will review in more detail the results obtained on simple planar and

  3. Secondary electron emission studied by secondary electron energy loss coincidence spectroscopy (SE2ELCS)

    International Nuclear Information System (INIS)

    Khalid, R.

    2013-01-01

    Emission of secondary electrons is of importance in many branches of fundamental and applied science. It is widely applied in the electron microscope for the investigation of the structure and electronic state of solid surfaces and particle detection in electron multiplier devices, and generally it is related to the energy dissipation of energetic particles moving inside a solid. The process of secondary electron emission is a complex physical phenomenon, difficult to measure experimentally and treat theoretically with satisfactory accuracy. The secondary electron spectrum measured with single electron spectroscopy does not provide detailed information of the energy loss processes responsible for the emission of secondary electrons. This information can be accessed when two correlated electron pairs are measured in coincidence and the pair consists of a backscattered electron after a given energy loss and a resulting emitted secondary electron. To investigate the mechanisms responsible for the emission of secondary electrons, a reflection (e,2e) coincidence spectrometer named Secondary Electron Electron Energy Loss Coincidence Spectrometer (SE2ELCS) has been developed in the framework of this thesis which allows one to uncover the relation between the features in the spectra which are due to energy losses and true secondary electron emission structures. The correlated electron pairs are measured with a hemispherical mirror analyzer (HMA) and a time of flight analyzer (TOF) by employing a continuous electron beam. An effort has been made to increase the coincidence count rate by increasing the effective solid angle of the TOF analyzer and optimizing the experimental parameters to get optimum energy resolution. Double differential coincidence spectra for a number of materials namely, nearly free electron metals (Al, Si), noble metals (Ag, Au, Cu, W) and highly oriented pyrolytic graphite (HOPG) have been measured using this coincidence spectrometer. The

  4. Electron energy-loss spectroscopy of single nanocrystals: mapping of tin allotropes

    Science.gov (United States)

    Roesgaard, Søren; Ramasse, Quentin; Chevallier, Jacques; Fyhn, Mogens; Julsgaard, Brian

    2018-05-01

    Using monochromated electron energy-loss spectroscopy (EELS), we are able to map different allotropes in Sn-nanocrystals embedded in Si. It is demonstrated that α-Sn and β-Sn, as well as an interface related plasmon, can be distinguished in embedded Sn-nanostructures. The EELS data is interpreted by standard non-negative matrix factorization followed by a manual Lorentzian decomposition. The decomposition allows for a more physical understanding of the EELS mapping without reducing the level of information. Extending the analysis from a reference system to smaller nanocrystals demonstrates that allotrope determination in nanoscale systems down below 5 nm is possible. Such local information proves the use of monochromated EELS mapping as a powerful technique to study nanoscale systems. This possibility enables investigation of small nanostructures that cannot be investigated through other means, allowing for a better understanding and thus leading to realizations that can result in nanomaterials with improved properties.

  5. Nanoscale probing of bandgap states on oxide particles using electron energy-loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qianlang [School for the Engineering of Matter, Transport and Energy, Arizona State University, 85287 AZ (United States); March, Katia [Laboratoire de Physique des Solides, Bâtiment 510, Université Paris-Sud, 91405 Orsay Cedex (France); Crozier, Peter A., E-mail: CROZIER@asu.edu [School for the Engineering of Matter, Transport and Energy, Arizona State University, 85287 AZ (United States)

    2017-07-15

    Surface and near-surface electronic states were probed with nanometer spatial resolution in MgO and TiO{sub 2} anatase nanoparticles using ultra-high energy resolution electron energy-loss spectroscopy (EELS) coupled to a scanning transmission electron microscope (STEM). This combination allows the surface electronic structure determined with spectroscopy to be correlated with nanoparticle size, morphology, facet etc. By acquiring the spectra in aloof beam mode, radiation damage to the surface can be significantly reduced while maintaining the nanometer spatial resolution. MgO and TiO{sub 2} showed very different bandgap features associated with the surface/sub-surface layer of the nanoparticles. Spectral simulations based on dielectric theory and density of states models showed that a plateau feature found in the pre-bandgap region in the spectra from (100) surfaces of 60 nm MgO nanocubes is consistent with a thin hydroxide surface layer. The spectroscopy shows that this hydroxide species gives rise to a broad filled surface state at 1.1 eV above the MgO valence band. At the surfaces of TiO{sub 2} nanoparticles, pronounced peaks were observed in the bandgap region, which could not be well fitted to defect states. In this case, the high refractive index and large particle size may make Cherenkov or guided light modes the likely causes of the peaks. - Highlights: • Bandgap states detected with aloof beam monochromated EELS on oxide nanoparticle surfaces. • Dielectric theory applied to simulate the spectra and interpret surface structure. • Density of states models also be employed to understand the surface electronic structure. • In MgO, one states associate with water species was found close to the valence band edge. • In anatase, two mid-gap states associated with point defects were found.

  6. Mapping boron in silicon solar cells using electron energy-loss spectroscopy

    DEFF Research Database (Denmark)

    in the energies of plasmon peaks in the low loss region [5]. We use these approaches to characterize both a thick n-p junction and the 10-nm-thick p-doped layer of a working solar cell. [1] U. Kroll, C. Bucher, S. Benagli, I. Schönbächler, J. Meier, A. Shah, J. Ballutaud, A. Howling, Ch. Hollenstein, A. Büchel, M......Amorphous silicon solar cells typically consist of stacked layers deposited on plastic or metallic substrates making sample preparation for transmission electron microscopy (TEM) difficult. The amorphous silicon layer - the active part of the solar cell - is sandwiched between 10-nm-thick n- and p...... resolution using TEM is highly challenging [3]. Recently, scanning TEM (STEM) combined with electron energy-loss spectroscopy (EELS) and spherical aberration-correction has allowed the direct detection of dopant concentration of 10^20cm-3 in 65-nm-wide silicon devices [4]. Here, we prepare TEM samples...

  7. Time-of-flight electron energy loss spectroscopy using TM110 deflection cavities

    Directory of Open Access Journals (Sweden)

    W. Verhoeven

    2016-09-01

    Full Text Available We demonstrate the use of two TM110 resonant cavities to generate ultrashort electron pulses and subsequently measure electron energy losses in a time-of-flight type of setup. The method utilizes two synchronized microwave cavities separated by a drift space of 1.45 m. The setup has an energy resolution of 12 ± 2 eV FWHM at 30 keV, with an upper limit for the temporal resolution of 2.7 ± 0.4 ps. Both the time and energy resolution are currently limited by the brightness of the tungsten filament electron gun used. Through simulations, it is shown that an energy resolution of 0.95 eV and a temporal resolution of 110 fs can be achieved using an electron gun with a higher brightness. With this, a new method is provided for time-resolved electron spectroscopy without the need for elaborate laser setups or expensive magnetic spectrometers.

  8. Direct characterization of the energy level alignments and molecular components in an organic hetero-junction by integrated photoemission spectroscopy and reflection electron energy loss spectroscopy analysis.

    Science.gov (United States)

    Yun, Dong-Jin; Shin, Weon-Ho; Bulliard, Xavier; Park, Jong Hwan; Kim, Seyun; Chung, Jae Gwan; Kim, Yongsu; Heo, Sung; Kim, Seong Heon

    2016-08-26

    A novel, direct method for the characterization of the energy level alignments at bulk-heterojunction (BHJ)/electrode interfaces on the basis of electronic spectroscopy measurements is proposed. The home-made in situ photoemission system is used to perform x-ray/ultraviolet photoemission spectroscopy (XPS/UPS), reflection electron energy loss spectroscopy (REELS) and inverse photoemission spectroscopy of organic-semiconductors (OSCs) deposited onto a Au substrate. Through this analysis system, we are able to obtain the electronic structures of a boron subphthalocyanine chloride:fullerene (SubPC:C60) BHJ and those of the separate OSC/electrode structures (SubPC/Au and C60/Au). Morphology and chemical composition analyses confirm that the original SubPC and C60 electronic structures remain unchanged in the electrodes prepared. Using this technique, we ascertain that the position and area of the nearest peak to the Fermi energy (EF = 0 eV) in the UPS (REELS) spectra of SubPC:C60 BHJ provide information on the highest occupied molecular orbital level (optical band gap) and combination ratio of the materials, respectively. Thus, extracting the adjusted spectrum from the corresponding SubPC:C60 BHJ UPS (REELS) spectrum reveals its electronic structure, equivalent to that of the C60 materials. This novel analytical approach allows complete energy-level determination for each combination ratio by separating its electronic structure information from the BHJ spectrum.

  9. Direct Detection Electron Energy-Loss Spectroscopy: A Method to Push the Limits of Resolution and Sensitivity.

    Science.gov (United States)

    Hart, James L; Lang, Andrew C; Leff, Asher C; Longo, Paolo; Trevor, Colin; Twesten, Ray D; Taheri, Mitra L

    2017-08-15

    In many cases, electron counting with direct detection sensors offers improved resolution, lower noise, and higher pixel density compared to conventional, indirect detection sensors for electron microscopy applications. Direct detection technology has previously been utilized, with great success, for imaging and diffraction, but potential advantages for spectroscopy remain unexplored. Here we compare the performance of a direct detection sensor operated in counting mode and an indirect detection sensor (scintillator/fiber-optic/CCD) for electron energy-loss spectroscopy. Clear improvements in measured detective quantum efficiency and combined energy resolution/energy field-of-view are offered by counting mode direct detection, showing promise for efficient spectrum imaging, low-dose mapping of beam-sensitive specimens, trace element analysis, and time-resolved spectroscopy. Despite the limited counting rate imposed by the readout electronics, we show that both core-loss and low-loss spectral acquisition are practical. These developments will benefit biologists, chemists, physicists, and materials scientists alike.

  10. Electronic and optical properties of Fe, Pd, and Ti studied by reflection electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Tahir, Dahlang; Kraaer, Jens; Tougaard, Sven

    2014-01-01

    We have studied the electronic and optical properties of Fe, Pd, and Ti by reflection electron energy-loss spectroscopy (REELS). REELS spectra recorded for primary energies in the range from 300 eV to 10 keV were corrected for multiple inelastically scattered electrons to determine the effective inelastic-scattering cross section. The dielectric functions and optical properties were determined by comparing the experimental inelastic-electron scattering cross section with a simulated cross section calculated within the semi-classical dielectric response model in which the only input is Im(−1/ε) by using the QUEELS-ε(k,ω)-REELS software package. The complex dielectric functions ε(k,ω), in the 0–100 eV energy range, for Fe, Pd, and Ti were determined from the derived Im(−1/ε) by Kramers-Kronig transformation and then the refractive index n and extinction coefficient k. The validity of the applied model was previously tested and found to give consistent results when applied to REELS spectra at energies between 300 and 1000 eV taken at widely different experimental geometries. In the present paper, we provide, for the first time, a further test on its validity and find that the model also gives consistent results when applied to REELS spectra in the full range of primary electron energies from 300 eV to 10000 eV. This gives confidence in the validity of the applied method.

  11. Electron energy loss spectroscopy microanalysis and imaging in the transmission electron microscope: example of biological applications

    International Nuclear Information System (INIS)

    Diociaiuti, Marco

    2005-01-01

    This paper reports original results obtained in our laboratory over the past few years in the application of both electron energy loss spectroscopy (EELS) and electron spectroscopy imaging (ESI) to biological samples, performed in two transmission electron microscopes (TEM) equipped with high-resolution electron filters and spectrometers: a Gatan model 607 single magnetic sector double focusing EEL serial spectrometer attached to a Philips 430 TEM and a Zeiss EM902 Energy Filtering TEM. The primary interest was on the possibility offered by the combined application of these spectroscopic techniques with those offered by the TEM. In particular, the electron beam focusing available in a TEM allowed us to perform EELS and ESI on very small sample volumes, where high-resolution imaging and electron diffraction techniques can provide important structural information. I show that ESI was able to improve TEM performance, due to the reduced chromatic aberration and the possibility of avoiding the sample staining procedure. Finally, the analysis of the oscillating extended energy loss fine structure (EXELFS) beyond the ionization edges characterizing the EELS spectra allowed me, in a manner very similar to the extended X-ray absorption fine structure (EXAFS) analysis of the X-ray absorption spectra, to obtain short-range structural information for such light elements of biological interest as O or Fe. The Philips EM430 (250-300 keV) TEM was used to perform EELS microanalysis on Ca, P, O, Fe, Al and Si. The assessment of the detection limits of this method was obtained working with well-characterized samples containing Ca and P, and mimicking the actual cellular matrix. I applied EELS microanalysis to Ca detection in bone tissue during the mineralization process and to P detection in the cellular membrane of erythrocytes treated with an anti-tumoral drug, demonstrating that the cellular membrane is a drug target. I applied EELS microanalysis and selected area electron

  12. High resolution spectroscopy of H+ energy loss in thin carbon film

    International Nuclear Information System (INIS)

    Matsunami, Noriaki; Kitoh, Kenshin

    1991-05-01

    The energy loss of ∼100 keV H + transmitted through thin carbon film of ∼7 nm has been measured with the resolution of ∼20 eV. We have observed new energy loss peaks around 210 and 400 eV in addition to the normal energy loss peak around 1 keV. We find that the experimental artifacts, ionization of C K-(290 eV) and impurity inner-shells, extreme non-uniformity of films, events associated with elastic scattering are not responsible for these peaks. The origin of these low energy loss peaks will be discussed. (author)

  13. Quantitative nanoscale water mapping in frozen-hydrated skin by low-loss electron energy-loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yakovlev, Sergey [Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Misra, Manoj; Shi, Shanling [Unilever Research and Development, Trumbull, CT 06611 (United States); Firlar, Emre [Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Libera, Matthew, E-mail: mlibera@stevens.edu [Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ 07030 (United States)

    2010-06-15

    Spatially resolved low-loss electron energy-loss spectroscopy (EELS) is a powerful method to quantitatively determine the water distribution in frozen-hydrated biological materials at high spatial resolution. However, hydrated tissue, particularly its hydrophilic protein-rich component, is very sensitive to electron radiation. This sensitivity has traditionally limited the achievable spatial resolution because of the relatively high noise associated with low-dose data acquisition. We show that the damage caused by high-dose data acquisition affects the accuracy of a multiple-least-squares (MLS) compositional analysis because of inaccuracies in the reference spectrum used to represent the protein. Higher spatial resolution combined with more accurate compositional analysis can be achieved if a reference spectrum is used that better represents the electron-beam-damaged protein component under frozen-hydrated conditions rather than one separately collected from dry protein under low-dose conditions. We thus introduce a method to extract the best-fitting protein reference spectrum from an experimental spectrum dataset. This method can be used when the MLS-fitting problem is sufficiently constrained so that the only unknown is the reference spectrum for the protein component. We apply this approach to map the distribution of water in cryo-sections obtained from frozen-hydrated tissue of porcine skin. The raw spectral data were collected at doses up to 10{sup 5} e/nm{sup 2} despite the fact that observable damage begins at doses as low as 10{sup 3} e/nm{sup 2}. The resulting spatial resolution of 10 nm is 5-10 times better than that in previous studies of frozen-hydrated tissue and is sufficient to resolve sub-cellular water fluctuations as well as the inter-cellular lipid-rich regions of skin where water-mediated processes are believed to play a significant role in the phenotype of keratinocytes in the stratum corneum.

  14. Quantitative nanoscale water mapping in frozen-hydrated skin by low-loss electron energy-loss spectroscopy

    International Nuclear Information System (INIS)

    Yakovlev, Sergey; Misra, Manoj; Shi, Shanling; Firlar, Emre; Libera, Matthew

    2010-01-01

    Spatially resolved low-loss electron energy-loss spectroscopy (EELS) is a powerful method to quantitatively determine the water distribution in frozen-hydrated biological materials at high spatial resolution. However, hydrated tissue, particularly its hydrophilic protein-rich component, is very sensitive to electron radiation. This sensitivity has traditionally limited the achievable spatial resolution because of the relatively high noise associated with low-dose data acquisition. We show that the damage caused by high-dose data acquisition affects the accuracy of a multiple-least-squares (MLS) compositional analysis because of inaccuracies in the reference spectrum used to represent the protein. Higher spatial resolution combined with more accurate compositional analysis can be achieved if a reference spectrum is used that better represents the electron-beam-damaged protein component under frozen-hydrated conditions rather than one separately collected from dry protein under low-dose conditions. We thus introduce a method to extract the best-fitting protein reference spectrum from an experimental spectrum dataset. This method can be used when the MLS-fitting problem is sufficiently constrained so that the only unknown is the reference spectrum for the protein component. We apply this approach to map the distribution of water in cryo-sections obtained from frozen-hydrated tissue of porcine skin. The raw spectral data were collected at doses up to 10 5 e/nm 2 despite the fact that observable damage begins at doses as low as 10 3 e/nm 2 . The resulting spatial resolution of 10 nm is 5-10 times better than that in previous studies of frozen-hydrated tissue and is sufficient to resolve sub-cellular water fluctuations as well as the inter-cellular lipid-rich regions of skin where water-mediated processes are believed to play a significant role in the phenotype of keratinocytes in the stratum corneum.

  15. Joint density of states of wide-band-gap materials by electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Fan, X.D.; Peng, J.L.; Bursill, L.A.

    1998-01-01

    Kramers-Kronig analysis for parallel electron energy loss spectroscopy (PEELS) data is developed as a software package. When used with a JEOL 4000EX high-resolution transmission electron microscope (HRTEM) operating at 100 keV this allows us to obtain the dielectric function of relatively wide band gap materials with an energy resolution of approx 1.4 eV. The imaginary part of the dielectric function allows the magnitude of the band gap to be determined as well as the joint-density-of-states function. Routines for obtaining three variations of the joint-density of states function, which may be used to predict the optical and dielectric response for angle-resolved or angle-integration scattering geometries are also described. Applications are presented for diamond, aluminum nitride (AlN), quartz (SiO 2 ) and sapphire (Al 2 O 3 ). The results are compared with values of the band gap and density of states results for these materials obtained with other techniques. (authors)

  16. Electronic excitation of furfural as probed by high-resolution vacuum ultraviolet spectroscopy, electron energy loss spectroscopy, and ab initio calculations

    Science.gov (United States)

    Ferreira da Silva, F.; Lange, E.; Limão-Vieira, P.; Jones, N. C.; Hoffmann, S. V.; Hubin-Franskin, M.-J.; Delwiche, J.; Brunger, M. J.; Neves, R. F. C.; Lopes, M. C. A.; de Oliveira, E. M.; da Costa, R. F.; Varella, M. T. do N.; Bettega, M. H. F.; Blanco, F.; García, G.; Lima, M. A. P.; Jones, D. B.

    2015-10-01

    The electronic spectroscopy of isolated furfural (2-furaldehyde) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 3.5-10.8 eV energy-range, with absolute cross section measurements derived. Electron energy loss spectra are also measured over a range of kinematical conditions. Those energy loss spectra are used to derive differential cross sections and in turn generalised oscillator strengths. These experiments are supported by ab initio calculations in order to assign the excited states of the neutral molecule. The good agreement between the theoretical results and the measurements allows us to provide the first quantitative assignment of the electronic state spectroscopy of furfural over an extended energy range.

  17. Electronic excitation of furfural as probed by high-resolution vacuum ultraviolet spectroscopy, electron energy loss spectroscopy, and ab initio calculations

    International Nuclear Information System (INIS)

    Ferreira da Silva, F.; Lange, E.; Limão-Vieira, P.; Jones, N. C.; Hoffmann, S. V.; Hubin-Franskin, M.-J.; Delwiche, J.; Brunger, M. J.

    2015-01-01

    The electronic spectroscopy of isolated furfural (2-furaldehyde) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 3.5–10.8 eV energy-range, with absolute cross section measurements derived. Electron energy loss spectra are also measured over a range of kinematical conditions. Those energy loss spectra are used to derive differential cross sections and in turn generalised oscillator strengths. These experiments are supported by ab initio calculations in order to assign the excited states of the neutral molecule. The good agreement between the theoretical results and the measurements allows us to provide the first quantitative assignment of the electronic state spectroscopy of furfural over an extended energy range

  18. Electronic excitation of furfural as probed by high-resolution vacuum ultraviolet spectroscopy, electron energy loss spectroscopy, and ab initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira da Silva, F.; Lange, E. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Limão-Vieira, P., E-mail: plimaovieira@fct.unl.pt, E-mail: michael.brunger@flinders.edu.au, E-mail: maplima@ifi.unicamp.br [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Jones, N. C.; Hoffmann, S. V. [ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade, DK-8000 Århus C (Denmark); Hubin-Franskin, M.-J.; Delwiche, J. [Départment de Chimie, Institut de Chimie-Bât. B6C, Université de Liège, B-4000 Liège 1 (Belgium); Brunger, M. J., E-mail: plimaovieira@fct.unl.pt, E-mail: michael.brunger@flinders.edu.au, E-mail: maplima@ifi.unicamp.br [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); and others

    2015-10-14

    The electronic spectroscopy of isolated furfural (2-furaldehyde) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 3.5–10.8 eV energy-range, with absolute cross section measurements derived. Electron energy loss spectra are also measured over a range of kinematical conditions. Those energy loss spectra are used to derive differential cross sections and in turn generalised oscillator strengths. These experiments are supported by ab initio calculations in order to assign the excited states of the neutral molecule. The good agreement between the theoretical results and the measurements allows us to provide the first quantitative assignment of the electronic state spectroscopy of furfural over an extended energy range.

  19. Detection of water and its derivatives on individual nanoparticles using vibrational electron energy-loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Crozier, Peter A., E-mail: crozier@asu.edu [School for the Engineering of Matter, Transport and Energy, Arizona State University, 501 E. Tyler Mall, Tempe, AZ 85287-6106 (United States); Aoki, Toshihiro [LeRoy Eyring Center for Solid State Science, Arizona State University, Tempe, AZ 85287-1704 (United States); Liu, Qianlang [School for the Engineering of Matter, Transport and Energy, Arizona State University, 501 E. Tyler Mall, Tempe, AZ 85287-6106 (United States)

    2016-10-15

    Understanding the role of water, hydrate and hydroxyl species on nanoparticle surfaces and interfaces is very important in both physical and life sciences. Detecting the presence of oxygen-hydrogen species with nanometer resolution is extremely challenging at present. Here we show that the recently developed vibrational electron energy-loss spectroscopy using subnanometer focused electron beams can be employed to spectroscopically identify the local presence and variation of OH species on nanoscale surfaces. The hydrogen-oxygen fingerprint can be correlated with highly localized structural and morphological information obtained from electron imaging. Moreover, the current approach exploits the aloof beam mode of spectral acquisition which does not require direct electron irradiation of the sample thus greatly reducing beam damage to the OH bond. These findings open the door for using electron microscopy to probe local hydroxyl and hydrate species on nanoscale organic and inorganic structures. - Highlights: • High spatial resolution spectroscopic detection of water related species in nanoparticles. • Detection of OH stretch modes with vibrational EELS. • Differentiation between hydrate and hydroxide species on or on nanoparticles. • Detection of hydrate on a single 60 nm oxide nanoparticle of MgO. • Use of aloof beam EELS to minimize radiation damage.

  20. Vibrational Surface Electron-Energy-Loss Spectroscopy Probes Confined Surface-Phonon Modes

    Directory of Open Access Journals (Sweden)

    Hugo Lourenço-Martins

    2017-12-01

    Full Text Available Recently, two reports [Krivanek et al. Nature (London 514, 209 (2014NATUAS0028-083610.1038/nature13870, Lagos et al. Nature (London 543, 529 (2017NATUAS0028-083610.1038/nature21699] have demonstrated the amazing possibility to probe vibrational excitations from nanoparticles with a spatial resolution much smaller than the corresponding free-space phonon wavelength using electron-energy-loss spectroscopy (EELS. While Lagos et al. evidenced a strong spatial and spectral modulation of the EELS signal over a nanoparticle, Krivanek et al. did not. Here, we show that discrepancies among different EELS experiments as well as their relation to optical near- and far-field optical experiments [Dai et al. Science 343, 1125 (2014SCIEAS0036-807510.1126/science.1246833] can be understood by introducing the concept of confined bright and dark surface phonon modes, whose density of states is probed by EELS. Such a concise formalism is the vibrational counterpart of the broadly used formalism for localized surface plasmons [Ouyang and Isaacson Philos. Mag. B 60, 481 (1989PMABDJ1364-281210.1080/13642818908205921, García de Abajo and Aizpurua Phys. Rev. B 56, 15873 (1997PRBMDO0163-182910.1103/PhysRevB.56.15873, García de Abajo and Kociak Phys. Rev. Lett. 100, 106804 (2008PRLTAO0031-900710.1103/PhysRevLett.100.106804, Boudarham and Kociak Phys. Rev. B 85, 245447 (2012PRBMDO1098-012110.1103/PhysRevB.85.245447]; it makes it straightforward to predict or interpret phenomena already known for localized surface plasmons such as environment-related energy shifts or the possibility of 3D mapping of the related surface charge densities [Collins et al. ACS Photonics 2, 1628 (2015APCHD52330-402210.1021/acsphotonics.5b00421].

  1. Single atom spectroscopy: Decreased scattering delocalization at high energy losses, effects of atomic movement and X-ray fluorescence yield.

    Science.gov (United States)

    Tizei, Luiz H G; Iizumi, Yoko; Okazaki, Toshiya; Nakanishi, Ryo; Kitaura, Ryo; Shinohara, Hisanori; Suenaga, Kazu

    2016-01-01

    Single atom localization and identification is crucial in understanding effects which depend on the specific local environment of atoms. In advanced nanometer scale materials, the characteristics of individual atoms may play an important role. Here, we describe spectroscopic experiments (electron energy loss spectroscopy, EELS, and Energy Dispersed X-ray spectroscopy, EDX) using a low voltage transmission electron microscope designed towards single atom analysis. For EELS, we discuss the advantages of using lower primary electron energy (30 keV and 60 keV) and higher energy losses (above 800 eV). The effect of atomic movement is considered. Finally, we discuss the possibility of using atomically resolved EELS and EDX data to measure the fluorescence yield for X-ray emission. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Single atom spectroscopy: Decreased scattering delocalization at high energy losses, effects of atomic movement and X-ray fluorescence yield

    International Nuclear Information System (INIS)

    Tizei, Luiz H.G.; Iizumi, Yoko; Okazaki, Toshiya; Nakanishi, Ryo; Kitaura, Ryo; Shinohara, Hisanori; Suenaga, Kazu

    2016-01-01

    Single atom localization and identification is crucial in understanding effects which depend on the specific local environment of atoms. In advanced nanometer scale materials, the characteristics of individual atoms may play an important role. Here, we describe spectroscopic experiments (electron energy loss spectroscopy, EELS, and Energy Dispersed X-ray spectroscopy, EDX) using a low voltage transmission electron microscope designed towards single atom analysis. For EELS, we discuss the advantages of using lower primary electron energy (30 keV and 60 keV) and higher energy losses (above 800 eV). The effect of atomic movement is considered. Finally, we discuss the possibility of using atomically resolved EELS and EDX data to measure the fluorescence yield for X-ray emission.

  3. Angle-resolved electron energy loss spectroscopy in hexagonal boron nitride

    Science.gov (United States)

    Fossard, Frédéric; Sponza, Lorenzo; Schué, Léonard; Attaccalite, Claudio; Ducastelle, François; Barjon, Julien; Loiseau, Annick

    2017-09-01

    Electron energy loss spectra were measured on hexagonal boron nitride single crystals employing an electron energy loss spectroscopic setup composed of an electron microscope equipped with a monochromator and an in-column filter. This setup provides high-quality energy-loss spectra and allows also for the imaging of energy-filtered diffraction patterns. These two acquisition modes provide complementary pieces of information, offering a global view of excitations in reciprocal space. As an example of the capabilities of the method we show how easily the core loss spectra at the K edges of boron and nitrogen can be measured and imaged. Low losses associated with interband and/or plasmon excitations are also measured. This energy range allows us to illustrate that our method provides results whose quality is comparable to that obtained from nonresonant x-ray inelastic scattering but with advantageous specificities such as an enhanced sensitivity at low q and a much greater simplicity and versatility that make it well adapted to the study of two-dimensional materials and related heterostructures. Finally, by comparing theoretical calculations to our measures, we are able to relate the range of applicability of ab initio calculations to the anisotropy of the sample and assess the level of approximation required for a proper simulation of our acquisition method.

  4. Phonon spectrum of single-crystalline FeSe probed by high-resolution electron energy-loss spectroscopy

    Science.gov (United States)

    Zakeri, Khalil; Engelhardt, Tobias; Le Tacon, Matthieu; Wolf, Thomas

    2018-06-01

    Utilizing high-resolution electron energy-loss spectroscopy (HREELS) we measure the phonon frequencies of β-FeSe(001), cleaved under ultra-high vacuum conditions. At the zone center (Γ bar-point) three prominent loss features are observed at loss energies of about ≃ 20.5 and 25.6 and 40 meV. Based on the scattering selection rules we assign the observed loss features to the A1g, B1g, and A2u phonon modes of β-FeSe(001). The experimentally measured phonon frequencies do not agree with the results of density functional based calculations in which a nonmagnetic, a checkerboard or a strip antiferromagnetic order is assumed for β-FeSe(001). Our measurements suggest that, similar to the other Fe-based materials, magnetism has a profound impact on the lattice dynamics of β-FeSe(001).

  5. Electronic properties of Mn-phthalocyanine–C60 bulk heterojunctions: Combining photoemission and electron energy-loss spectroscopy

    International Nuclear Information System (INIS)

    Roth, Friedrich; Herzig, Melanie; Knupfer, Martin; Lupulescu, Cosmin; Darlatt, Erik; Gottwald, Alexander; Eberhardt, Wolfgang

    2015-01-01

    The electronic properties of co-evaporated mixtures (blends) of manganese phthalocyanine and the fullerene C 60 (MnPc:C 60 ) have been studied as a function of the concentration of the two constituents using two supplementary electron spectroscopic methods, photoemission spectroscopy (PES) and electron energy-loss spectroscopy (EELS) in transmission. Our PES measurements provide a detailed picture of the electronic structure measured with different excitation energies as well as different mixing ratios between MnPc and C 60 . Besides a relative energy shift, the occupied electronic states of the two materials remain essentially unchanged. The observed energy level alignment is different compared to that of the related CuPc:C 60 bulk heterojunction. Moreover, the results from our EELS investigations show that, despite the rather small interface interaction, the MnPc related electronic excitation spectrum changes significantly by admixing C 60 to MnPc thin films

  6. Spin flip inelastic scattering in electron energy loss spectroscopy of a ferromagnetic metal

    International Nuclear Information System (INIS)

    Bocchetta, C.J.; Tosatti, E.; Yin, S.

    1986-11-01

    A model ferromagnetic metal is used to calculate the spin-polarization which occurs during inelastic electron-metal scattering with the production of an electron-hole pair. The polarization is found to have contributions from unequal spin-flip as well as non-flip energy loss rates. Our results indicate an asymmetry of the order of a few percent with parameters roughly modelling iron. (author)

  7. Study of ion tracks by micro-probe ion energy loss spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Vacík, Jiří; Havránek, Vladimír; Hnatowicz, Vladimír; Horák, Pavel; Fink, Dietmar; Apel, P. Yu.

    2014-01-01

    Roč. 332, AUG (2014), s. 308-311 ISSN 0168-583X. [21st International Conference on Ion Beam Analysis (IBA). Seattle, 23.06.2013-28.06.2013] R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : ion energy loss spectrometry * single ion track * microprobe * tomography Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.124, year: 2014

  8. Spin-flip inelastic scattering in electron energy loss spectroscopy of a ferromagnetic metal

    International Nuclear Information System (INIS)

    Yin, S.; Tosatti, E.

    1981-08-01

    We calculate the spin polarization occuring during electron inelastic scattering from electron-hole pairs in a model ferromagnetic metal. The polarization is found to have contributions from unequal spin flip as well as non-flip energy loss rates. Our results indicate an asymmetry of the order of a few percent with parameters roughly modeling Fsub(e). The possibilities of comparison with experiments in the presence of simultaneous spin-polarizing elastic scattering are discussed. (author)

  9. Structural defects in multiferroic BiMnO3 studied by transmission electron microscopy and electron energy-loss spectroscopy

    International Nuclear Information System (INIS)

    Yang, H.; Chi, Z. H.; Yao, L. D.; Zhang, W.; Li, F. Y.; Jin, C. Q.; Yu, R. C.

    2006-01-01

    The multiferroic material BiMnO 3 synthesized under high pressure has been systematically studied by transmission electron microscopy and electron energy-loss spectroscopy, and some important structural defects are revealed in this multiferroic material. The frequently observed defects are characterized to be Σ3(111) twin boundaries, Ruddlesden-Popper [Acta Crystallogr. 11, 54 (1958)] antiphase boundaries, and a p p superdislocations connected with a small segment of Ruddlesden-Popper defect. These defects are present initially in the as-synthesized sample. In addition, we find that ordered voids (oxygen vacancies) are easily introduced into the multiferroic BiMnO 3 by electron-beam irradiation

  10. A reverse Monte Carlo method for deriving optical constants of solids from reflection electron energy-loss spectroscopy spectra

    International Nuclear Information System (INIS)

    Da, B.; Sun, Y.; Ding, Z. J.; Mao, S. F.; Zhang, Z. M.; Jin, H.; Yoshikawa, H.; Tanuma, S.

    2013-01-01

    A reverse Monte Carlo (RMC) method is developed to obtain the energy loss function (ELF) and optical constants from a measured reflection electron energy-loss spectroscopy (REELS) spectrum by an iterative Monte Carlo (MC) simulation procedure. The method combines the simulated annealing method, i.e., a Markov chain Monte Carlo (MCMC) sampling of oscillator parameters, surface and bulk excitation weighting factors, and band gap energy, with a conventional MC simulation of electron interaction with solids, which acts as a single step of MCMC sampling in this RMC method. To examine the reliability of this method, we have verified that the output data of the dielectric function are essentially independent of the initial values of the trial parameters, which is a basic property of a MCMC method. The optical constants derived for SiO 2 in the energy loss range of 8-90 eV are in good agreement with other available data, and relevant bulk ELFs are checked by oscillator strength-sum and perfect-screening-sum rules. Our results show that the dielectric function can be obtained by the RMC method even with a wide range of initial trial parameters. The RMC method is thus a general and effective method for determining the optical properties of solids from REELS measurements.

  11. Radiative interaction of a focused relativistic electron beam in energy-loss spectroscopy of nanoscopic platelets

    International Nuclear Information System (INIS)

    Itskovsky, M. A.; Maniv, T.; Cohen, H.

    2008-01-01

    A quantum-mechanical scattering theory for relativistic, highly focused electron beams in the vacuum near nanoscopic platelets is presented, revealing an excitation mechanism due to the electron wave scattering from the platelet edges. Radiative electromagnetic excitations within the light cone are shown to arise, allowed by the breakdown of momentum conservation along the beam axis in the inelastic-scattering process. Calculated for metallic (silver and gold) and insulating (SiO 2 and MgO) nanoplatelets, radiative features are revealed above the main surface-plasmon-polariton peak, and dramatic enhancements in the electron-energy-loss probability at gaps of the 'classical' spectra are found. The corresponding radiation should be detectable in the vacuum far-field zone, with e beams exploited as sensitive 'tip detectors' of electronically excited nanostructures

  12. Radiative interaction of a focused relativistic electron beam in energy-loss spectroscopy of nanoscopic platelets

    Science.gov (United States)

    Itskovsky, M. A.; Cohen, H.; Maniv, T.

    2008-07-01

    A quantum-mechanical scattering theory for relativistic, highly focused electron beams in the vacuum near nanoscopic platelets is presented, revealing an excitation mechanism due to the electron wave scattering from the platelet edges. Radiative electromagnetic excitations within the light cone are shown to arise, allowed by the breakdown of momentum conservation along the beam axis in the inelastic-scattering process. Calculated for metallic (silver and gold) and insulating ( SiO2 and MgO) nanoplatelets, radiative features are revealed above the main surface-plasmon-polariton peak, and dramatic enhancements in the electron-energy-loss probability at gaps of the “classical” spectra are found. The corresponding radiation should be detectable in the vacuum far-field zone, with e beams exploited as sensitive “tip detectors” of electronically excited nanostructures.

  13. Reflection electron energy loss spectroscopy as efficient technique for the determination of optical properties of polystyrene intermixed with gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Deris, Jamileh [Department of Physics, Yasouj University, Yasouj 75918-74831 (Iran, Islamic Republic of); Hajati, Shaaker, E-mail: Hajati@mail.yu.ac.ir [Department of Physics, Yasouj University, Yasouj 75918-74831 (Iran, Islamic Republic of); Department of Semiconductors, Materials and Energy Research Center, Karaj 3177983634 (Iran, Islamic Republic of)

    2017-01-15

    Highlights: • Reflection Electron Energy Loss Spectroscopy of nano-metalized polymer. • Determination of real part of the dielectric function of nanostructured sample. • Determination of imaginary part of the dielectric function of nanostructured sample. • Determination of refractive index and coefficient of extinction of the sample. • Determination of reflection and absorption coefficients of nano-metalized Polymer. - Abstract: The electronic properties (electron inelastic cross section, energy loss function) of a nano-metalized polystyrene obtained by reflection electron energy loss spectroscopy (REELS) in a previous study [J. Deris, S. Hajati, S. Tougaard, V. Zaporojtchenko, Appl. Surf. Sci. 377 (2016) 44–47], which relies on the Yubero-Tougaard method, were used in the complementary application of Kramers-Kronig transformation to determine its optical properties such as the real part (ε{sub 1}) and imaginary part (ε{sub 2}) of the dielectric function (ε), refractive index (n), coefficients of extinction (k), reflection (R) and absorption (μ). The degree of intermixing of polystyrene thin film and gold nanoparticles of sizes 5.5 nm was controlled by annealing the sample to achieve a morphology in which the nanoparticles were homogeneously distributed within polystyrene. It is worth noting that no data are available on the optical properties of metalized polymers such as gold nanoparticles intermixed with polystyrene. Therefore, this work is of high importance in terms of both the sample studied here and the method applied. The advantage of the method applied here is that no information on the lateral distribution of the nanocomposite sample is required. This means that the REELS technique has been presented here to suitably, efficiently and easily obtain the optical properties of such nano-metalized polymer in which the metal nanoparticles have been vertically well distributed (homogeneous in depth). Therefore, for vertically homogeneous and

  14. Electronic energy states of HfSe/sub 2/ and NbSe/sub 2/ by low energy electron loss spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Ito, T; Iwami, M; Hiraki, A [Osaka Univ., Suita (Japan). Faculty of Engineering

    1981-06-01

    Low energy electron loss spectroscopy (ELS) study was performed on 1T-HfSe/sub 2/ (group IVB metal compound) and 2H-NbSe/sub 2/ (group VB metal compound) by using incident electron energies of 30-250 eV. From the loss data in the second derivative form, maxima in density-of-states in the conduction band of the compounds were deduced through the information on the filled core states by X-ray photoelectron spectroscopy. The conduction band of the transition-metal dichalcogenides could be divided into two parts. The results are discussed in relation to the previous work on WS/sub 2/ (group VIB metal compound), and also to proposals based on band calculations and experimental studies on the transition-metal dichalcogenides with constituent metals of group IVB, VB and VIB.

  15. Band gap and defect states of MgO thin films investigated using reflection electron energy loss spectroscopy

    Directory of Open Access Journals (Sweden)

    Sung Heo

    2015-07-01

    Full Text Available The band gap and defect states of MgO thin films were investigated by using reflection electron energy loss spectroscopy (REELS and high-energy resolution REELS (HR-REELS. HR-REELS with a primary electron energy of 0.3 keV revealed that the surface F center (FS energy was located at approximately 4.2 eV above the valence band maximum (VBM and the surface band gap width (EgS was approximately 6.3 eV. The bulk F center (FB energy was located approximately 4.9 eV above the VBM and the bulk band gap width was about 7.8 eV, when measured by REELS with 3 keV primary electrons. From a first-principles calculation, we confirmed that the 4.2 eV and 4.9 eV peaks were FS and FB, induced by oxygen vacancies. We also experimentally demonstrated that the HR-REELS peak height increases with increasing number of oxygen vacancies. Finally, we calculated the secondary electron emission yields (γ for various noble gases. He and Ne were not influenced by the defect states owing to their higher ionization energies, but Ar, Kr, and Xe exhibited a stronger dependence on the defect states owing to their small ionization energies.

  16. Two dimensional CCD [charged coupled device] arrays as parallel detectors in electron energy loss and x-ray wavelength dispersive spectroscopy

    International Nuclear Information System (INIS)

    Zaluzec, N.J.

    1988-08-01

    Parallel detection systems for spectroscopy have generally been based upon linear detector arrays. Replacing the linear arrays with two dimensional systems yields more complicated devices; however, there are corresponding benefits which can be realized for both x-ray and electron energy loss spectroscopy. The operational design of these systems, as well as preliminary results from the construction of such a device used for electron spectroscopy, are presented. 10 refs., 8 figs

  17. Tracking of boron-labelled monoclonal antibodies by energy loss spectroscopy in the electron microscope: a preliminary report

    International Nuclear Information System (INIS)

    Moore, D.E.; Dawes, A.L.; Chandler, A.K.; Bradstock, K.F.

    1990-01-01

    A technique is being developed, based on electron energy loss spectroscopy in the transmission electron microscope, whereby the binding of monoclonal antibodies to their specific receptors and any subsequent movement or endocytosis can be studied in cell culture. The method requires that antibodies be labelled with a low atomic number element, such as boron. Two procedures have been established enabling up to 1200 boron atoms to be attached per antibody molecule without affecting the immunoreactivity. In the first method, dodecaborane cages are attached to polyornithine bridging molecules which in turn are covalently bound to the antibody using a photosensitive reagent. The second technique makes use of the extremely high biotin-avidin affinity by attaching biotin to the antibody and dodecaborane cages to avidin before mixing the two components. 13 refs., 2 figs

  18. The uniformity study of non-oxide thin film at device level using electron energy loss spectroscopy

    Science.gov (United States)

    Li, Zhi-Peng; Zheng, Yuankai; Li, Shaoping; Wang, Haifeng

    2018-05-01

    Electron energy loss spectroscopy (EELS) has been widely used as a chemical analysis technique to characterize materials chemical properties, such as element valence states, atoms/ions bonding environment. This study provides a new method to characterize physical properties (i.e., film uniformity, grain orientations) of non-oxide thin films in the magnetic device by using EELS microanalysis on scanning transmission electron microscope. This method is based on analyzing white line ratio of spectra and related extended energy loss fine structures so as to correlate it with thin film uniformity. This new approach can provide an effective and sensitive method to monitor/characterize thin film quality (i.e., uniformity) at atomic level for thin film development, which is especially useful for examining ultra-thin films (i.e., several nanometers) or embedded films in devices for industry applications. More importantly, this technique enables development of quantitative characterization of thin film uniformity and it would be a remarkably useful technique for examining various types of devices for industrial applications.

  19. Electron energy-loss spectroscopy characterization and microwave absorption of iron-filled carbon-nitrogen nanotubes

    International Nuclear Information System (INIS)

    Che Renchao; Liang Chongyun; Shi Honglong; Zhou Xingui; Yang Xinan

    2007-01-01

    Iron-filled carbon-nitrogen (Fe/CN x ) nanotubes and iron-filled carbon (Fe/C) nanotubes were synthesized at 900 deg. C through a pyrolysis reaction of ferrocene/acetonitrile and ferrocene/xylene, respectively. The differences of structure and composition between the Fe/CN x nanotubes and Fe/C nanotubes were investigated by transmission electron microscopy and electron energy-loss spectroscopy (EELS). It was found that the morphology of Fe/CN x nanotubes is more corrugated than that of the Fe/C nanotubes due to the incorporation of nitrogen. By comparing the Fe L 2,3 electron energy-loss spectra of Fe/CN x nanotubes to those of the Fe/C nanotubes, the electron states at the interface between Fe and the tubular wall of both Fe/CN x nanotubes and Fe/C nanotubes were investigated. At the boundary between Fe and the wall of a CN x nanotube, the additional electrons contributed from the doped 'pyridinic-like' nitrogen might transfer to the empty 3d orbital of the encapsulated iron, therefore leading to an intensity suppression of the iron L 2,3 edge and an intensity enhancement of the carbon K edge. However, such an effect could not be found in Fe/C nanotubes. Microwave absorption properties of both Fe/CN x and Fe/C nanocomposites at 2-18 GHz band were studied

  20. High-resolution electron-energy-loss spectroscopy studies of clean and hydrogen-covered tungsten (100) surfaces

    International Nuclear Information System (INIS)

    Woods, J.P.

    1986-01-01

    High-resolution (10-meV FWHM) low-energy (≤ 100eV) electrons are scattered from the tungsten (100) surface. Electron-energy-loss spectroscopy (EELS) selection rules are utilized to identify vibrational modes of the surface tungsten atoms. A 36-meV mode is measured on the c(2 X 2) thermally reconstructed surface and is modeled as an overtone of the 18-meV mode at M in the surface Brillouin zone. The superstructure of the reconstructed surface allows this mode to be observed in specular scattering. The surface tungsten atoms return to their bulk lateral positions with saturated hydrogen (β 1 phase) adsorption; and a 26-meV mode identified is due to the perpendicular vibration of the surface tungsten layers. The clean-room temperature surface does not display either low-energy vibrations and the surface is modeled as disordered. The three β 1 phase hydrogen vibrations are observed and a new vibration at 118 meV is identified. The 118-meV cross section displays characteristics of a parallel mode, but calculations show this assignment to be erroneous. There are two hydrogen atoms for each surface tungsten atom in the β 1 phase, and lattice-dynamical calculations show that the 118-meV mode is due to a hydrogen-zone edge vibration. The predicted breakdown of the parallel hydrogen vibration selection rule was not observed

  1. Studying substrate effects on localized surface plasmons in an individual silver nanoparticle using electron energy-loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fujiyoshi, Yoshifumi; Nemoto, Takashi; Kurata, Hiroki, E-mail: kurata@eels.kuicr.kyoto-u.ac.jp

    2017-04-15

    In this study, electron energy-loss spectroscopy (EELS) in conjunction with scanning transmission electron microscopy (STEM) was used to investigate surface plasmons in a single silver nanoparticle (NP) on a magnesium oxide substrate, employing an incident electron trajectory parallel to the substrate surface. This parallel irradiation allowed a direct exploration of the substrate effects on localized surface plasmon (LSP) excitations as a function of the distance from the substrate. The presence of the substrate was found to lower the symmetry of the system, such that the resonance energies of LSPs were dependent on the polarization direction relative to the substrate surface. The resulting mode splitting could be detected by applying different electron trajectories, providing results similar to those previously obtained from optical studies using polarized light. However, the LSP maps obtained by STEM-EELS analysis show an asymmetric intensity distribution with the highest intensity at the top surface of the NP (that is, far from the substrate), a result that is not predicted by optical simulations. We show that modifications of the applied electric field by the substrate cause this asymmetric intensity distribution in the LSP maps.

  2. Fluctuating Charge-Order in Optimally Doped Bi- 2212 Revealed by Momentum-resolved Electron Energy Loss Spectroscopy

    Science.gov (United States)

    Husain, Ali; Vig, Sean; Kogar, Anshul; Mishra, Vivek; Rak, Melinda; Mitrano, Matteo; Johnson, Peter; Gu, Genda; Fradkin, Eduardo; Norman, Michael; Abbamonte, Peter

    Static charge order is a ubiquitous feature of the underdoped cuprates. However, at optimal doping, charge-order has been thought to be completely suppressed, suggesting an interplay between the charge-ordering and superconducting order parameters. Using Momentum-resolved Electron Energy Loss Spectroscopy (M-EELS) we show the existence of diffuse fluctuating charge-order in the optimally doped cuprate Bi2Sr2CaCu2O8+δ (Bi-2212) at low-temperature. We present full momentum-space maps of both elastic and inelastic scattering at room temperature and below the superconducting transition with 4meV resolution. We show that the ``rods'' of diffuse scattering indicate nematic-like fluctuations, and the energy width defines a fluctuation timescale of 160 fs. We discuss the implications of fluctuating charge-order on the dynamics at optimal doping. This work was supported by the Gordon and Betty Moore Foundation's EPiQS Initiative through Grant GBMF-4542. An early prototype of the M-EELS instrument was supported by the DOE Center for Emergent Superconductivity under Award No. DE-AC02-98CH10886.

  3. Optical Dark-Field and Electron Energy Loss Imaging and Spectroscopy of Symmetry-Forbidden Modes in Loaded Nanogap Antennas.

    Science.gov (United States)

    Brintlinger, Todd; Herzing, Andrew A; Long, James P; Vurgaftman, Igor; Stroud, Rhonda; Simpkins, B S

    2015-06-23

    We have produced large numbers of hybrid metal-semiconductor nanogap antennas using a scalable electrochemical approach and systematically characterized the spectral and spatial character of their plasmonic modes with optical dark-field scattering, electron energy loss spectroscopy with principal component analysis, and full wave simulations. The coordination of these techniques reveal that these nanostructures support degenerate transverse modes which split due to substrate interactions, a longitudinal mode which scales with antenna length, and a symmetry-forbidden gap-localized transverse mode. This gap-localized transverse mode arises from mode splitting of transverse resonances supported on both antenna arms and is confined to the gap load enabling (i) delivery of substantial energy to the gap material and (ii) the possibility of tuning the antenna resonance via active modulation of the gap material's optical properties. The resonant position of this symmetry-forbidden mode is sensitive to gap size, dielectric strength of the gap material, and is highly suppressed in air-gapped structures which may explain its absence from the literature to date. Understanding the complex modal structure supported on hybrid nanosystems is necessary to enable the multifunctional components many seek.

  4. Identification of hydrogen and deuterium at the surface of water ice by reflection electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Yubero, F.; Toekesi, K.

    2009-01-01

    Complete text of publication follows. The study of elastically backscattered electrons from surfaces by reflection electron energy loss spectroscopy (REELS) has been recently recommended as an alternative technique to quantify the H content at the surface of a-C:H and polymer samples. This analysis is based on the fact that the energy loss of the incident electrons due to the recoil effect depends on the atomic mass of the particular atom present at the surface. The observed difference in recoil energies between H and O atoms (about 2 eV for 1.5 keV primary electrons) can be easily measured with standard electron spectrometers used in surface analysis. In this paper we go one step forward to explore if, with the same experimental approach, it is possible to differentiate between hydrogen and deuterium (D) in the surface region of a sample. This capability could be important for technological fields such as surface functionalization, where it is desired to distinguish between H and D at surfaces after interaction with labeled compounds. We have chosen normal and deuterated water as test labeled compounds because this polar molecule is of key importance in numerous surface reactions. It has been shown that H and D can be easily distinguished at the surface of water ice [4] using standard REELS measurements with 1000 - 1650 eV primary-electron energies, i.e., a surface analytical technique. Differences in recoil energies of the O - H and O - D atom pairs present in H 2 O and D 2 O have been found to agree with MC simulations (see Fig.1). There are many possible applications of H and D detection by REELS. Among many others, this study opens the possibility of nondestructive studies of deuterium-labeled atoms present or adsorbed on surfaces. For example, studies of H incorporation into a polymer or carbonbased surface after plasma activation with gas mixtures with several labeled molecules containing H atoms. Acknowledgements F.Y. thanks the Spanish Ministry of Science

  5. Temperature-dependent surface structure, composition, and electronic properties of the clean SrTiO3(111) crystal face: Low-energy-electron diffraction, Auger-electron spectroscopy, electron energy loss, and ultraviolet-photoelectron spectroscopy studies

    International Nuclear Information System (INIS)

    Lo, W.J.; Somorjai, G.A.

    1978-01-01

    Low-energy-electron diffraction, Auger-electron spectroscopy, electron-energy-loss, and ultraviolet-photoelectron spectroscopies were used to study the structure, composition, and electron energy distribution of a clean single-crystal (111) face of strontium titanate (perovskite). The dependence of the surface chemical composition on the temperature has been observed along with corresponding changes in the surface electronic properties. High-temperature Ar-ion bombardment causes an irreversible change in the surface structure, stoichiometry, and electron energy distribution. In contrast to the TiO 2 surface, there are always significant concentrations of Ti 3+ in an annealed ordered SrTiO 3 (111) surface. This stable active Ti 3+ monolayer on top of a substrate with large surface dipole potential makes SrTiO 3 superior to TiO 2 when used as a photoanode in the photoelectrochemical cell

  6. Elektron energy-loss spectroscopy on p-type doped high-Tc superconductors and undoped parent compounds

    International Nuclear Information System (INIS)

    Romberg, H.

    1991-12-01

    In this work the electronic structure of HTSC, mainly La 2-x Sr x CuO 4+y and YBa 2 Cu 3 O 7-y , was investigated by electron energy-loss spectroscopy (EELS). Core-level spectroscopy on the O 1s level yields information on the quantity and character of unoccupied O 2p-states near the Fermi level. In the undoped parent compounds of the HTSC, an admixture of ≥ 10% unoccupied O 2p-states to the conduction band (Cu 3d 10 band or upper Hubbard band) is observed. These O 2p-states are polarized parallel to the CuO 2 -plane (La 2 CuO 4 and Nd 2 CuO 4 ). In La 2 CuO 4 , Nd 2 CuO 4 , YBa 2 Cu 3 O 6 , Bi 2 Sr 2 CaCu 2 O 8 and Tl 2 Ba 2 CaCu 2 O 8 , the unoccupied Cu 3d-states are mainly polarized in the CuO 2 plane an admixture of about 10% to 20% of probably Cu 3d 3z 2 -r 2 states. A similar behaviour in the planes and chains in YBa 2 Cu 3 O 7 is in accordance with the experimental data. The observation of unoccupied states polarized orthogonal to the CuO 2 plane demands consideration of these states in theoretical models. No difference in energetic positions of unoccupied Cu 3d x 2 -y 2 and Cu 3d 3z 2 -r 2 states was observed in disagreement with some X-ray absorption data. Thus, theoretical models which correlate T c -values with this energy difference, are disproved. There is evidence for some admixture of unoccupied Cu 3d 3z 2 -r 2 states but no sign of a separate Cu 3d 3z 2 -r 2 band which was proposed to cross the Fermi level upon doping. Low energy EELS data have provided the dielectric function between 0.5 and 50 eV. (orig./GSCH) [de

  7. High resolution electron energy loss spectroscopy of clean and hydrogen covered Si(001) surfaces: first principles calculations.

    Science.gov (United States)

    Patterson, C H

    2012-09-07

    Surface phonons, conductivities, and loss functions are calculated for reconstructed (2×1), p(2×2) and c(4×2) clean Si(001) surfaces, and (2×1) H and D covered Si(001) surfaces. Surface conductivities perpendicular to the surface are significantly smaller than conductivities parallel to the surface. The surface loss function is compared to high resolution electron energy loss measurements. There is good agreement between calculated loss functions and experiment for H and D covered surfaces. However, agreement between experimental data from different groups and between theory and experiment is poor for clean Si(001) surfaces. Formalisms for calculating electron energy loss spectra are reviewed and the mechanism of electron energy losses to surface vibrations is discussed.

  8. Electron energy-loss spectroscopy on n-type doped high-temperature superconductors and related systems

    International Nuclear Information System (INIS)

    Alexander, M.

    1992-08-01

    Electron-enery loss spectroscopy measurements on n-type doped high temperature superconductors, their undoped parent compounds, Y-doped Bi 2 Sr 2 CaCu 2 O 8 and some rare earth oxides are presented. The undoped parent compounds Ln 2 CuO 4 (Ln = Pr, Nd, Sm) are charge transfer insulators with a charge transfer energy gap of 1.4 eV. The conduction band lies in the CuO 2 plane and has mainly Cu3d x 2 -y 2 character. O2p x,y states are slightly hybridized with this band. Upon partially substituting the trivalent Ln ions by tetravalent Ce or Th and monovalent F for the O ions, electron doping of the CuO 2 plane occurs with the electrons having mainly Cu3d character. A rigid band behaviour is proposed by several band structure calculations could be ruled out, as well as the occurence of so called 'mid-gap' states appearing inside the band gap between the valence and conduction bands. The position of the Fermi level was found to be at the bottom of the conduction bands. No measurable influence of the reduction process, necessary to obtain superconductivity, was detected in the unoccupied density of states. Characteristics shifts of the measured oxygen and copper edges were correlated with crossing the metal-insulator transition. These shifts are most probably caused by an improved screening capacity of the free charge carriers. A similar effect was also observed in Y-doped Bi 2 Sr 2 CaCu 2 O 8 . Thus, it was possible to show that the disappearance of the valence band hole states upon doping did not occur in a rigid-band-like manner. The low energy excitations in Nd 1.85 Ce 0.15 CuO 4-δ showed a plasmon like excitation at about 1 eV as well as a reduction and an energy shift of the charge transfer excitation. The dispersion of this plasmon excitation was determined. (orig.)

  9. High energy-resolution electron energy-loss spectroscopy study of the dielectric properties of bulk and nanoparticle LaB6 in the near-infrared region

    International Nuclear Information System (INIS)

    Sato, Yohei; Terauchi, Masami; Mukai, Masaki; Kaneyama, Toshikatsu; Adachi, Kenji

    2011-01-01

    The dielectric properties of LaB 6 crystals and the plasmonic behavior of LaB 6 nanoparticles, which have been applied to solar heat-shielding filters, were studied by high energy-resolution electron energy-loss spectroscopy (HR-EELS). An EELS spectrum of a LaB 6 crystal showed a peak at 2.0 eV, which was attributed to volume plasmon excitation of carrier electrons. EELS spectra of single LaB 6 nanoparticles showed peaks at 1.1-1.4 eV depending on the dielectric effect from the substrates. The peaks were assigned to dipole oscillation excitations. These peak energies almost coincided with the peak energy of optical absorption of a heat-shielding filter with LaB 6 nanoparticles. On the other hand, those energies were a smaller than a dipole oscillation energy predicted using the dielectric function of bulk LaB 6 crystal. It is suggested that the lower energy than expected is due to an excitation at 1.2 eV, which was observed for oxidized LaB 6 area. -- Highlights: → The dielectric properties of LaB 6 nanoparticles applied to solar heat-shielding filters were studied by HR-EELS. → Plasmon peak energies of the LaB 6 nanoparticles were almost equal to optical absorption energy of a heat-shielding filter. → From this result, near-infrared optical absorption of the filter is due to the surface dipole mode of the nanoparticles.

  10. Energy losses in switches

    International Nuclear Information System (INIS)

    Martin, T.H.; Seamen, J.F.; Jobe, D.O.

    1993-01-01

    The authors experiments show energy losses between 2 and 10 times that of the resistive time predictions. The experiments used hydrogen, helium, air, nitrogen, SF 6 polyethylene, and water for the switching dielectric. Previously underestimated switch losses have caused over predicting the accelerator outputs. Accurate estimation of these losses is now necessary for new high-efficiency pulsed power devices where the switching losses constitute the major portion of the total energy loss. They found that the switch energy losses scale as (V peak I peak ) 1.1846 . When using this scaling, the energy losses in any of the tested dielectrics are almost the same. This relationship is valid for several orders of magnitude and suggested a theoretical basis for these results. Currents up to .65 MA, with voltages to 3 MV were applied to various gaps during these experiments. The authors data and the developed theory indicates that the switch power loss continues for a much longer time than the resistive time, with peak power loss generally occurring at peak current in a ranging discharge instead of the early current time. All of the experiments were circuit code modeled after developing a new switch loss version based on the theory. The circuit code predicts switch energy loss and peak currents as a function of time. During analysis of the data they noticed slight constant offsets between the theory and data that depended on the dielectric. They modified the plasma conductivity for each tested dielectric to lessen this offset

  11. Study of semiconductor valence plasmon line shapes via electron energy-loss spectroscopy in the transmission electron microscope

    International Nuclear Information System (INIS)

    Kundmann, M.K.

    1988-11-01

    Electron energy-loss spectra of the semiconductors Si, AlAs, GaAs, InAs, InP, and Ge are examined in detail in the regime of outer-shell and plasmon energy losses (0--100eV). Particular emphasis is placed on modeling and analyzing the shapes of the bulk valence plasmon lines. A line shape model based on early work by Froehlich is derived and compared to single-scattering probability distributions extracted from the measured spectra. Model and data are found to be in excellent agreement, thus pointing the way to systematic characterization of the plasmon component of EELS spectra. The model is applied to three separate investigations. 82 refs

  12. Evidence for CO formation in irradiated methanol and acetone: contribution of low-energy electron-energy-loss spectroscopy to γ-radiolysis

    International Nuclear Information System (INIS)

    Jay-Gerin, J.-P.; Fraser, M.-J.; Michaud, M.; Sanche, L.; Swiderek, P.; Ferradini, C.

    1997-01-01

    Energy-loss spectra for low-energy electrons incident on acetone condensed on a multilayer film of argon, and on a methanol film deposited on a metallic substrate, are reported. In both cases, the formation of carbon monoxide has been detected. These results are directly related to those obtained in the liquid-phase γ-radiolysis of the two compounds. (author)

  13. Auger electron spectroscopy, ionization loss spectroscopy, appearance potential spectroscopy

    International Nuclear Information System (INIS)

    Riwan, R.

    1973-01-01

    The spectroscopy of surfaces using an incident electron beam is studied. The fundamental mechanisms are discussed together with the parameters involved in Auger emission: excitation of the atom, de-excitation by electron emission, and the migration of electrons towards the surface and their ejection. Some examples of applications are given (surface structures, metallurgy, chemical information). Two new techniques for analyzing surfaces are studied: ionization spectroscopy, and appearance potential spectroscopy [fr

  14. Free electrons and ionic liquids: study of excited states by means of electron-energy loss spectroscopy and the density functional theory multireference configuration interaction method.

    Science.gov (United States)

    Regeta, Khrystyna; Bannwarth, Christoph; Grimme, Stefan; Allan, Michael

    2015-06-28

    The technique of low energy (0-30 eV) electron impact spectroscopy, originally developed for gas phase molecules, is applied to room temperature ionic liquids (IL). Electron energy loss (EEL) spectra recorded near threshold, by collecting 0-2 eV electrons, are largely continuous, assigned to excitation of a quasi-continuum of high overtones and combination vibrations of low-frequency modes. EEL spectra recorded by collecting 10 eV electrons show predominantly discrete vibrational and electronic bands. The vibrational energy-loss spectra correspond well to IR spectra except for a broadening (∼0.04 eV) caused by the liquid surroundings, and enhanced overtone activity indicating a contribution from resonant excitation mechanism. The spectra of four representative ILs were recorded in the energy range of electronic excitations and compared to density functional theory multireference configuration interaction (DFT/MRCI) calculations, with good agreement. The spectra up to about 8 eV are dominated by π-π* transitions of the aromatic cations. The lowest bands were identified as triplet states. The spectral region 2-8 eV was empty in the case of a cation without π orbitals. The EEL spectrum of a saturated solution of methylene green in an IL band showed the methylene green EEL band at 2 eV, indicating that ILs may be used as a host to study nonvolatile compounds by this technique in the future.

  15. Observability of localized magnetoplasmons in quantum dots: Scrutinizing the eligibility of far-infrared, Raman, and electron-energy-loss spectroscopies

    Directory of Open Access Journals (Sweden)

    Manvir S. Kushwaha

    2016-03-01

    Full Text Available We investigate a one-component, quasi-zero dimensional, quantum plasma exposed to a parabolic potential and an applied magnetic field in the symmetric gauge. If the size of such a system as can be realized in the semiconducting quantum dots is on the order of the de-Broglie wavelength, the electronic and optical properties become highly tunable. Then the quantum size effects challenge the observation of many-particle phenomena such as the magneto-optical absorption, Raman intensity, and electron energy-loss spectrum. An exact analytical solution of the problem leads us to infer that these many-particle phenomena are, in fact, dictated by the generalized Kohn’s theorem (GKT in the long-wavelength limit. Maneuvering the confinement and/or the magnetic field furnishes the resonance energies capable of being explored with the FIR, Raman, and/or electron-energy-loss spectroscopy. This implies that either of these probes is competent in observing the localized magnetoplasmons in the system. As an application of the rigorous analytical diagnosis of the system, we have presented various pertinent single-particle, such as Fock-Darwin spectrum, Fermi energy, zigzag excitation spectrum, and magneto-optical transitions, and the many-particle phenomena, such as magneto-optical absorption, Raman intensity, and electron energy-loss probability. In the latter, the energy position of the resonance peaks is observed to be independent of the electron-electron interactions and hence of the number of electrons in the quantum dot in compliance with the GKT. It is found that both confinement potential and magnetic field play a decisive role in influencing the aforementioned many-particle phenomena. Specifically, increasing (decreasing the strength of the confining potential is found to be analogous to shrinking (expanding the size of the quantum dots and results into a blue (red shift in the respective spectra. Intensifying the magnetic field has two-fold effects in

  16. Observability of localized magnetoplasmons in quantum dots: Scrutinizing the eligibility of far-infrared, Raman, and electron-energy-loss spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Kushwaha, Manvir S. [Department of Physics and Astronomy, Rice University, P.O. Box 1892, Houston, Texas 77251 (United States)

    2016-03-15

    We investigate a one-component, quasi-zero dimensional, quantum plasma exposed to a parabolic potential and an applied magnetic field in the symmetric gauge. If the size of such a system as can be realized in the semiconducting quantum dots is on the order of the de-Broglie wavelength, the electronic and optical properties become highly tunable. Then the quantum size effects challenge the observation of many-particle phenomena such as the magneto-optical absorption, Raman intensity, and electron energy-loss spectrum. An exact analytical solution of the problem leads us to infer that these many-particle phenomena are, in fact, dictated by the generalized Kohn’s theorem (GKT) in the long-wavelength limit. Maneuvering the confinement and/or the magnetic field furnishes the resonance energies capable of being explored with the FIR, Raman, and/or electron-energy-loss spectroscopy. This implies that either of these probes is competent in observing the localized magnetoplasmons in the system. As an application of the rigorous analytical diagnosis of the system, we have presented various pertinent single-particle, such as Fock-Darwin spectrum, Fermi energy, zigzag excitation spectrum, and magneto-optical transitions, and the many-particle phenomena, such as magneto-optical absorption, Raman intensity, and electron energy-loss probability. In the latter, the energy position of the resonance peaks is observed to be independent of the electron-electron interactions and hence of the number of electrons in the quantum dot in compliance with the GKT. It is found that both confinement potential and magnetic field play a decisive role in influencing the aforementioned many-particle phenomena. Specifically, increasing (decreasing) the strength of the confining potential is found to be analogous to shrinking (expanding) the size of the quantum dots and results into a blue (red) shift in the respective spectra. Intensifying the magnetic field has two-fold effects in the resonance

  17. Characterisation of nano-structured titanium and aluminium nitride coatings by indentation, transmission electron microscopy and electron energy loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Girleanu, M., E-mail: maria.girleanu@uha.fr [Mecanique, Materiaux et Procedes de Fabrication, LPMT (EA CNRS 4365), Universite de Haute Alsace, 61 rue Albert Camus, F-68093 Mulhouse (France); Pac, M.-J.; Louis, P. [Mecanique, Materiaux et Procedes de Fabrication, LPMT (EA CNRS 4365), Universite de Haute Alsace, 61 rue Albert Camus, F-68093 Mulhouse (France); Ersen, O.; Werckmann, J. [Departement Structures et Interfaces, IPCMS (UMR CNRS 7504), Universite de Strasbourg, 23 rue du Loess, F-67087 Strasbourg (France); Rousselot, C. [Departement Micro Nano Sciences et Systemes, FEMTO-ST (UMR CNRS 6174), Universite de Franche-Comte, BP 71427, F-25211 Montbeliard (France); Tuilier, M.-H. [Mecanique, Materiaux et Procedes de Fabrication, LPMT (EA CNRS 4365), Universite de Haute Alsace, 61 rue Albert Camus, F-68093 Mulhouse (France)

    2011-07-01

    Titanium and aluminium nitride Ti{sub 1-x}Al{sub x}N films deposited by radiofrequency magnetron reactive sputtering onto steel substrate are examined by transmission electron microscopy over all the range of composition (x = 0, 0.5, 0.68, 0.86, 1). The deposition parameters are optimised in order to grow nitride films with low stress over all the composition range. Transmission electron microscopy cross-section images of Vickers indentation prints performed on that set of coatings show the evolution of their damage behaviour as increasing x Al content. Cubic Ti-rich nitrides consist of small grains clustered in rather large columns sliding along each other during indentation. Hexagonal Al-rich films grow in thinner columns which can be bent under the Vickers tip. Indentation tests carried out on TiN and AlN films are simulated using finite element modelling. Particular aspects of shear stresses and displacements in the coating/substrate are investigated. The growth mode and the nanostructure of two typical films, TiN and Ti{sub 0.14}Al{sub 0.86}N, are studied in detail by combining transmission electron microscopy cross-sections and plan views. Electron energy loss spectrum taken across Ti{sub 0.14}Al{sub 0.86}N film suggests that a part of nitrogen atoms is in cubic-like local environment though the lattice symmetry of Al-rich coatings is hexagonal. The poorly crystallised domains containing Ti and N atoms in cubic-like environment are obviously located in grain boundaries and afford protection of the coating against cracking.

  18. Characterisation of nano-structured titanium and aluminium nitride coatings by indentation, transmission electron microscopy and electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Girleanu, M.; Pac, M.-J.; Louis, P.; Ersen, O.; Werckmann, J.; Rousselot, C.; Tuilier, M.-H.

    2011-01-01

    Titanium and aluminium nitride Ti 1-x Al x N films deposited by radiofrequency magnetron reactive sputtering onto steel substrate are examined by transmission electron microscopy over all the range of composition (x = 0, 0.5, 0.68, 0.86, 1). The deposition parameters are optimised in order to grow nitride films with low stress over all the composition range. Transmission electron microscopy cross-section images of Vickers indentation prints performed on that set of coatings show the evolution of their damage behaviour as increasing x Al content. Cubic Ti-rich nitrides consist of small grains clustered in rather large columns sliding along each other during indentation. Hexagonal Al-rich films grow in thinner columns which can be bent under the Vickers tip. Indentation tests carried out on TiN and AlN films are simulated using finite element modelling. Particular aspects of shear stresses and displacements in the coating/substrate are investigated. The growth mode and the nanostructure of two typical films, TiN and Ti 0.14 Al 0.86 N, are studied in detail by combining transmission electron microscopy cross-sections and plan views. Electron energy loss spectrum taken across Ti 0.14 Al 0.86 N film suggests that a part of nitrogen atoms is in cubic-like local environment though the lattice symmetry of Al-rich coatings is hexagonal. The poorly crystallised domains containing Ti and N atoms in cubic-like environment are obviously located in grain boundaries and afford protection of the coating against cracking.

  19. Electron-beam-induced reduction of Fe3+ in iron phosphate dihydrate, ferrihydrite, haemosiderin and ferritin as revealed by electron energy-loss spectroscopy

    International Nuclear Information System (INIS)

    Pan, Ying-Hsi; Vaughan, Gareth; Brydson, Rik; Bleloch, Andrew; Gass, Mhairi; Sader, Kasim; Brown, Andy

    2010-01-01

    The effect of high-energy electron irradiation on ferritin/haemosiderin cores (in an iron-overloaded human liver biopsy), its mineral analogue; six-line ferrihydrite (6LFh), and iron phosphate dihydrate (which has similar octahedral ferric iron to oxygen coordination to that in ferrihydrite and ferritin/haemosiderin cores) has been investigated using electron energy-loss spectroscopy (EELS). Fe L 2,3 -ionisation edges were recorded on two types of electron microscope: a 200 keV transmission electron microscope (TEM) and a 100 keV scanning transmission electron microscope (STEM), in order to investigate the damage mechanisms in operation and to establish a methodology for minimum specimen alteration during analytical electron microscopic characterisation. A specimen damage mechanism dominated by radiolysis that results in the preferential loss of iron co-ordinating ligands (O, OH and H 2 O) is discussed. The net result of irradiation is structural re-organisation and reduction of iron within the iron hydroxides. At sufficiently low electron fluence and particularly in the lower incident energy, finer probe diameter STEM, the alteration is shown to be minimal. All the materials examined exhibit damage which as a function of cumulative fluence is best fitted by an inverse power-law, implying that several chemical and structural changes occur in response to the electron beam and we suggest that these are governed by secondary processes arising from the primary ionisation event. This work affirms that electron fluence and current density should be considered when measuring mixed valence ratios with EELS.

  20. Electron-beam-induced reduction of Fe{sup 3+} in iron phosphate dihydrate, ferrihydrite, haemosiderin and ferritin as revealed by electron energy-loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Ying-Hsi; Vaughan, Gareth; Brydson, Rik [Institute for Materials Research, SPEME, University of Leeds, Leeds LS2 9JT (United Kingdom); Bleloch, Andrew; Gass, Mhairi [SuperSTEM, Daresbury Laboratories, Warrington WA4 4AD (United Kingdom); Sader, Kasim [Institute for Materials Research, SPEME, University of Leeds, Leeds LS2 9JT (United Kingdom); SuperSTEM, Daresbury Laboratories, Warrington WA4 4AD (United Kingdom); Brown, Andy, E-mail: a.p.brown@leeds.ac.uk [Institute for Materials Research, SPEME, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2010-07-15

    The effect of high-energy electron irradiation on ferritin/haemosiderin cores (in an iron-overloaded human liver biopsy), its mineral analogue; six-line ferrihydrite (6LFh), and iron phosphate dihydrate (which has similar octahedral ferric iron to oxygen coordination to that in ferrihydrite and ferritin/haemosiderin cores) has been investigated using electron energy-loss spectroscopy (EELS). Fe L{sub 2,3}-ionisation edges were recorded on two types of electron microscope: a 200 keV transmission electron microscope (TEM) and a 100 keV scanning transmission electron microscope (STEM), in order to investigate the damage mechanisms in operation and to establish a methodology for minimum specimen alteration during analytical electron microscopic characterisation. A specimen damage mechanism dominated by radiolysis that results in the preferential loss of iron co-ordinating ligands (O, OH and H{sub 2}O) is discussed. The net result of irradiation is structural re-organisation and reduction of iron within the iron hydroxides. At sufficiently low electron fluence and particularly in the lower incident energy, finer probe diameter STEM, the alteration is shown to be minimal. All the materials examined exhibit damage which as a function of cumulative fluence is best fitted by an inverse power-law, implying that several chemical and structural changes occur in response to the electron beam and we suggest that these are governed by secondary processes arising from the primary ionisation event. This work affirms that electron fluence and current density should be considered when measuring mixed valence ratios with EELS.

  1. High-resolution parallel electron energy-loss spectroscopy of MnL2,3-edges in inorganic manganese compounds

    International Nuclear Information System (INIS)

    Garvie, L.A.J.; Craven, A.J.

    1994-01-01

    Parallel electron energy-loss spectroscopy (PEELS) in a scanning transmission electron microscope (STEM) was used to record the Mn L 2,3 -edges from a range of natural and synthetic manganese containing materials, covering valences 0, II, III, IV and VII, with an energy resolution of ca. 0.5 eV. The Mn L 2,3 electron-loss near-edge structure (ELNES) of these edges provided a sensitive fingerprint of its valence. The Mn 2+ L 2,3 -edges show little sensitivity to the local site symmetry of the ligands surrounding the manganese. This is illustrated by comparing the Mn L 2,3 -edges from 4-, 6-and 8-fold coordinated Mn 2+ . In contrast, the Mn L 3 -edges from Mn 3+ and Mn 4+ containing minerals exhibited ELNES that are interpreted in terms of a crystals-field splitting of the 3d electrons, governed by the symmetry of the surrounding ligands. The Mn L 3 -edges for octahedrally coordinated Mn 2+ , Mn 3+ and Mn 4+ showed variations in their ELNES that were sensitive to the crystal-field strength. The crystal-field strength (10Q) was measured from these edges and compared very well with published optically determinted values. The magnitude of 10Dq measured from the Mn L 3 -edges and their O K-edge prepeaks of the manganese oxides were almost identical. This further confirms that the value of 10Dq measured at the Mn L 3 -edge is correct. Selected spectra are compared with theoretical 2p atomic multiplet spectra and the differences and similarities are explained in terms of the covalency and site symmetry of the manganese. The Mn L 3 -edges allow the valence of the manganese to be ascertained, even in multivalent state materials, and can also be used to dtermin 10Dq. (orig.)

  2. Electron energy loss spectroscopy of CH3N2CH3 adsorbed on Ni(100), Ni(111), Cr(100), Cr(111)

    International Nuclear Information System (INIS)

    Schulz, M.A.

    1985-07-01

    A study of the adsorption of CH 3 N 2 CH 3 on Ni(100), Ni(111), Cr(100), and Cr(111) using high resolution electron energy loss spectroscopy (EELS) is presented. Under approximately the same conditions of coverage, the vibrational spectra of CH 3 N 2 CH 3 on these four surfaces are quite distinct from one another, implying that the CH 3 N 2 CH 3 -substrate interaction is very sensitive to the physical and electronic structure of each surface. In addition to the room temperature studies, the evolution of surface species on the Ni(100) surface in the temperature range 300 to 425 K was studied. Analysis of the Ni(100) spectra indicates that molecular adsorption, probably through the N lone pair, occurs at room temperature. Spectra taken after annealing the CH 3 N 2 CH 3 -Ni(100) surfaces indicate that CH and CN bond scission occurred at the elevated temperatures. Decomposition of CH 3 N 2 CH 3 takes place on the Ni(111), Cr(100), and Cr(111) surfaces at room temperature, as evidenced by the intensity of the carbon-metal stretch in the corresponding spectra. Possible identities of coadsorbed dissociation products are considered. The stable coverage of surface species on all four surfaces at 300 K is less than one monolayer. A general description of an electron energy loss (EEL) spectrometer is given. Followed by a more specific discussion of some recent modifications to the EEL monochromator assembly used in this laboratory. Both the previous configuration of our monochromator and the new version are briefly described, as an aid to understanding the motivation for the changes as well as the differences in operation of the two versions. For clarity, the new monochromator design is referred to as variable pass, while the previous design is referred to as double pass. A modified tuning procedure for the new monochromator is also presented. 58 refs., 11 figs

  3. Particle energy loss spectroscopy and SEM studies of topography development in thin aluminium films implanted with high doses of helium

    International Nuclear Information System (INIS)

    Barfoot, K.M.; Webb, R.P.; Donnelly, S.E.

    1984-01-01

    Development of topography in thin (55.5 μg cm -2 ) self-supporting aluminium films, caused by high fluence (approx. 10 17 ions cm -2 ) irradiation with 5 keV helium ions, has been observed. This has been achieved by measuring the topography-enhanced energy straggling of 0.40 MeV 4 He + ions transmitted through the foils and detected with an electrostatic analyser of resolution 0.2 keV. Features, about 0.7 μm in width, are observed with scanning electron microscopy. TRIM Monte Carlo calculations of the implantation processes are performed in order to follow the helium implantation and damage depth distributions. It is deduced that a form of thin film micro-wrinkling has occurred which is caused by the relief of stress brought about by the implantation of helium. (author)

  4. Electronic structure of metastable bcc Cu–Cr alloy thin films: Comparison of electron energy-loss spectroscopy and first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Liebscher, C.H.; Freysoldt, C. [Max-Planck-Institut für Eisenforschung GmbH, 40237 Düsseldorf (Germany); Dennenwaldt, T. [Institute of Condensed Matter Physics and Interdisciplinary Center for Electron Microscopy, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne (Switzerland); Harzer, T.P.; Dehm, G. [Max-Planck-Institut für Eisenforschung GmbH, 40237 Düsseldorf (Germany)

    2017-07-15

    Metastable Cu–Cr alloy thin films with nominal thickness of 300 nm and composition of Cu{sub 67}Cr{sub 33} (at%) are obtained by co-evaporation using molecular beam epitaxy. The microstructure, chemical phase separation and electronic structure are investigated by transmission electron microscopy (TEM). The thin film adopts the body-centered cubic crystal structure and consists of columnar grains with ~50 nm diameter. Aberration-corrected scanning TEM in combination with energy dispersive X-ray spectroscopy confirms compositional fluctuations within the grains. Cu- and Cr-rich domains with composition of Cu{sub 85}Cr{sub 15} (at%) and Cu{sub 42}Cr{sub 58} (at%) and domain size of 1–5 nm are observed. The alignment of the interface between the Cu- and Cr-rich domains shows a preference for {110}-type habit plane. The electronic structure of the Cu–Cr thin films is investigated by electron energy loss spectroscopy (EELS) and is contrasted to an fcc-Cu reference sample. The experimental EEL spectra are compared to spectra computed by density functional theory. The main differences between bcc-and fcc-Cu are related to differences in van Hove singularities in the electron density of states. In Cu–Cr solid solutions with bcc crystal structure a single peak after the L{sub 3}-edge, corresponding to a van Hove singularity at the N-point of the first Brillouin zone is observed. Spectra computed for pure bcc-Cu and random Cu–Cr solid solutions with 10 at% Cr confirm the experimental observations. The calculated spectrum for a perfect Cu{sub 50}Cr{sub 50} (at%) random structure shows a shift in the van Hove singularity towards higher energy by developing a Cu–Cr d-band that lies between the delocalized d-bands of Cu and Cr. - Highlights: • Compositional fluctuations on the order of 1–5 nm in Cu- and Cr-rich domains are observed. • EELS determines a single van Hove singularity for bcc Cu–Cr solid solutions. • The electronic structure is dominated by d

  5. Direct band gap measurement of Cu(In,Ga)(Se,S)2 thin films using high-resolution reflection electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Heo, Sung; Lee, Hyung-Ik; Park, Jong-Bong; Ko, Dong-Su; Chung, JaeGwan; Kim, KiHong; Kim, Seong Heon; Yun, Dong-Jin; Ham, YongNam; Park, Gyeong Su; Song, Taewon; Lee, Dongho; Nam, Junggyu; Kang, Hee Jae; Choi, Pyung-Ho; Choi, Byoung-Deog

    2015-01-01

    To investigate the band gap profile of Cu(In 1−x ,Ga x )(Se 1−y S y ) 2 of various compositions, we measured the band gap profile directly as a function of in-depth using high-resolution reflection energy loss spectroscopy (HR-REELS), which was compared with the band gap profile calculated based on the auger depth profile. The band gap profile is a double-graded band gap as a function of in-depth. The calculated band gap obtained from the auger depth profile seems to be larger than that by HR-REELS. Calculated band gaps are to measure the average band gap of the spatially different varying compositions with respect to considering its void fraction. But, the results obtained using HR-REELS are to be affected by the low band gap (i.e., out of void) rather than large one (i.e., near void). Our findings suggest an analytical method to directly determine the band gap profile as function of in-depth

  6. Direct band gap measurement of Cu(In,Ga)(Se,S){sub 2} thin films using high-resolution reflection electron energy loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Sung [Analytical Engineering Group, Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); College of Information and Communication Engineering, Sungkyunkwan University, Cheoncheon-dong 300, Jangan-gu, Suwon 440-746 (Korea, Republic of); Lee, Hyung-Ik; Park, Jong-Bong; Ko, Dong-Su; Chung, JaeGwan; Kim, KiHong; Kim, Seong Heon; Yun, Dong-Jin; Ham, YongNam; Park, Gyeong Su [Analytical Engineering Group, Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); Song, Taewon [Energy lab, Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); Lee, Dongho, E-mail: dhlee0333@gmail.com; Nam, Junggyu [PV Development Team, Energy Solution Business Division, Samsung SDI, 467 Beonyeong-ro, Cheonan-si, Chungcheongnam-do 331-330 (Korea, Republic of); Kang, Hee Jae [Department of Physics, Chungbuk National University, Gaesin-dong, Heungdeok-gu, Cheongju, 361-763 (Korea, Republic of); Choi, Pyung-Ho; Choi, Byoung-Deog, E-mail: bdchoi@skku.edu [College of Information and Communication Engineering, Sungkyunkwan University, Cheoncheon-dong 300, Jangan-gu, Suwon 440-746 (Korea, Republic of)

    2015-06-29

    To investigate the band gap profile of Cu(In{sub 1−x},Ga{sub x})(Se{sub 1−y}S{sub y}){sub 2} of various compositions, we measured the band gap profile directly as a function of in-depth using high-resolution reflection energy loss spectroscopy (HR-REELS), which was compared with the band gap profile calculated based on the auger depth profile. The band gap profile is a double-graded band gap as a function of in-depth. The calculated band gap obtained from the auger depth profile seems to be larger than that by HR-REELS. Calculated band gaps are to measure the average band gap of the spatially different varying compositions with respect to considering its void fraction. But, the results obtained using HR-REELS are to be affected by the low band gap (i.e., out of void) rather than large one (i.e., near void). Our findings suggest an analytical method to directly determine the band gap profile as function of in-depth.

  7. Localization of calcium in the cyanobiont and gonidial zone of Cycas revoluta Thunb. by microelectrodes, chlorotetracycline, electron spectroscopic imaging and electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Caiola, M.G.; Canini, A.; Brandizzi, F.

    1994-01-01

    Ionic calcium concentration was measured in the gonidial zone of fresh coralloid roots by means of calcium microelectrodes. It was 10 -6 M in the apical segments of coralloid roots and increased to 10 -5 M in the gonidial zones of median and basal segments. Loosely membrane-bound calcium was evidenced by using chloro-tetracycline (CTC) or ethylene glycol-bis-(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) and CTC, in cell walls of columnar cells of Cycas and in the cytoplasm of cyanobiont. Sub-cellular localization of calcium was obtained by electron spectroscopic imaging (ESI) and electron energy loss spectroscopy (EELS) analyses applied at transmission electron microscopy on thin, unstained sections of gonidial zone of coralloid roots. By means of these techniques, bound-calcium was detected inside the mucilage of apical and median segments whereas, in the basal segments, it was completely absent. In the heterocysts of apical segments of coralloid, calcium was localized on the envelope, cell walls, thylakoids and cyanophycin granules. In the gonidial zone of the basal segments, dead or degenerating heterocysts completely lacked calcium. Therefore, the high ionic calcium amounts detected in the gonidial zone of median and basal segments could represent a minor calcium uptake by the cells or release by lysed ones. The decreases in nitrogenase activity recorded in the median and basal segments of the coralloid roots paralleled the decrease in calcium amount in heterocyst envelope. (authors)

  8. Dynamical observation of lithium insertion/extraction reaction during charge-discharge processes in Li-ion batteries by in situ spatially resolved electron energy-loss spectroscopy.

    Science.gov (United States)

    Shimoyamada, Atsushi; Yamamoto, Kazuo; Yoshida, Ryuji; Kato, Takehisa; Iriyama, Yasutoshi; Hirayama, Tsukasa

    2015-12-01

    All-solid-state Li-ion batteries (LIBs) with solid electrolytes are expected to be the next generation devices to overcome serious issues facing conventional LIBs with liquid electrolytes. However, the large Li-ion transfer resistance at the electrode/solid-electrolyte interfaces causes low power density and prevents practical use. In-situ-formed negative electrodes prepared by decomposing the solid electrolyte Li(1+x+3z)Alx(Ti,Ge)(2-x)Si(3z)P(3-z)O12 (LASGTP) with an excess Li-ion insertion reaction are effective electrodes providing low Li-ion transfer resistance at the interfaces. Prior to our work, however, it had still been unclear how the negative electrodes were formed in the parent solid electrolytes. Here, we succeeded in dynamically visualizing the formation by in situ spatially resolved electron energy-loss spectroscopy in a transmission electron microscope mode (SR-TEM-EELS). The Li-ions were gradually inserted into the solid electrolyte region around 400 nm from the negative current-collector/solid-electrolyte interface in the charge process. Some of the ions were then extracted in the discharge process, and the rest were diffused such that the distribution was almost flat, resulting in the negative electrodes. The redox reaction of Ti(4+)/Ti(3+) in the solid electrolyte was also observed in situ during the Li insertion/extraction processes. The in situ SR-TEM-EELS revealed the mechanism of the electrochemical reaction in solid-state batteries. © The Author 2015. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Loss of energy business

    International Nuclear Information System (INIS)

    Beer, G.

    2010-01-01

    Russian PM Vladimir Putin, euphoric about the signing of the 25-year contract for the use of Ukrainian seaports by the Russian Navy, announced several new strategic bilateral projects. The new partnership between the two countries might be a disappointment for those who were hoping for new Slovak energy business development in cooperation with Moscow. Representatives of the Russian company TVEL frequently visited the Slovak Ministry of Economy last year, discussing the idea of a nuclear fuel production plant in Slovakia. The factory was supposed to make fuel for the growing number of Russian reactors throughout Europe and utilize the recently discovered uranium deposits near Kosice. However, since Mr. Putin unveiled the idea of creating a Russian-Ukrainian nuclear holding at the site of the Khmelnitskaya Nuclear Power Plant, Slovakia will probably not become the gate to the EU for Russia's atomic business. Owners of the Slovak uranium deposit site are losing business too. And not only does the Slovak-Russian nuclear cooperation seem to be completely lost, but the gas transfer business is unclear too. Last week, the Russian gas company Gazprom showed that its selling prices are a matter of political bargaining rather than fair market value. Similar to low prices for the extremely friendly Belarus, Ukraine earned a $100 discount and in exchange for the Black Sea deal it will be paying only $236 per thousand cubic meters of the commodity. Russia thus gave up roughly $3 billion this year. Slovakia has nothing to offer in exchange for such a deal. Not only price creation but also the construction of gas pipelines through Europe remains a political issue for Russians. With plans to bypass Ukraine and Slovakia, the only safe future for the local transit system can be the result of an idea to pool Gazprom and Ukrainian Naftohaz transit assets together with a stock swap. (author)

  10. Energy losses on tokamak startup

    International Nuclear Information System (INIS)

    Murray, J.G.; Rothe, K.E.; Bronner, G.

    1983-01-01

    During the startup of a tokamak reactor using poloidal field (PF) coils to induce plasma currents, the conducting structures carry induced currents. The associated energy losses in the circuits must be provided by the startup coils and the PF system. This paper provides quantitative and comparitive values for the energies required as a function of the thickness or resistivity of the torus shells

  11. World offshore energy loss statistics

    International Nuclear Information System (INIS)

    Kaiser, Mark J.

    2007-01-01

    Offshore operations present a unique set of environmental conditions and adverse exposure not observed in a land environment taking place in a confined space in a hostile environment under the constant danger of catastrophe and loss. It is possible to engineer some risks to a very low threshold of probability, but losses and unforeseen events can never be entirely eliminated because of cost considerations, the human factor, and environmental uncertainty. Risk events occur infrequently but have the potential of generating large losses, as evident by the 2005 hurricane season in the Gulf of Mexico, which was the most destructive and costliest natural disaster in the history of offshore production. The purpose of this paper is to provide a statistical assessment of energy losses in offshore basins using the Willis Energy Loss database. A description of the loss categories and causes of property damage are provided, followed by a statistical assessment of damage and loss broken out by region, cause, and loss category for the time horizon 1970-2004. The impact of the 2004-2005 hurricane season in the Gulf of Mexico is summarized

  12. Loss energy states of nonstationary quantum systems

    International Nuclear Information System (INIS)

    Dodonov, V.V.; Man'ko, V.I.

    1978-01-01

    The concept of loss energy states is introduced. The loss energy states of the quantum harmonic damping oscillator are considered in detail. The method of constructing the loss energy states for general multidimensional quadratic nonstationary quantum systems is briefly discussed

  13. Electron energy-loss spectra in molecular fluorine

    Science.gov (United States)

    Nishimura, H.; Cartwright, D. C.; Trajmar, S.

    1979-01-01

    Electron energy-loss spectra in molecular fluorine, for energy losses from 0 to 17.0 eV, have been taken at incident electron energies of 30, 50, and 90 eV and scattering angles from 5 to 140 deg. Features in the spectra above 11.5 eV energy loss agree well with the assignments recently made from optical spectroscopy. Excitations of many of the eleven repulsive valence excited electronic states are observed and their location correlates reasonably well with recent theoretical results. Several of these excitations have been observed for the first time and four features, for which there are no identifications, appear in the spectra.

  14. Basic principles of ultrafast Raman loss spectroscopy

    Indian Academy of Sciences (India)

    field tries to drive the electron with its frequency. If the applied field is of the form E = E0eiωt , the driving ..... (CARS),8 coherent Stokes Raman scattering (CSRS), ... gain or loss process in which only two beams are required and it is a self ...

  15. Single atom identification by energy dispersive x-ray spectroscopy

    International Nuclear Information System (INIS)

    Lovejoy, T. C.; Dellby, N.; Krivanek, O. L.; Ramasse, Q. M.; Falke, M.; Kaeppel, A.; Terborg, R.; Zan, R.

    2012-01-01

    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.

  16. Nanoscale investigation of the degradation mechanism of a historical chrome yellow paint by quantitative electron energy loss spectroscopy mapping of chromium species.

    Science.gov (United States)

    Tan, Haiyan; Tian, He; Verbeeck, Jo; Monico, Letizia; Janssens, Koen; Van Tendeloo, Gustaaf

    2013-10-18

    Getting the picture: The investigation of 100 year old chrome yellow paint by transmission electron microscopy and spectroscopy has led to the identification of four types of core-shell particles. This nanoscale investigation has allowed a mechanism to be proposed for the darkening of some bright yellow colors in Van Gogh's paintings (e.g. in Falling leaves (Les Alyscamps), 1888). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Electron capture and energy-gain spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Taulbjerg, K.

    1989-01-01

    The applicability of translation energy spectroscopy as a tool to determine individual reaction cross sections in atomic collisions is analyzed with special emphasis on the electron capture process in highly charged ion collisions. A condition is derived to separate between higher collision energies where translation energy spectroscopy is problem free and lower energies where strong overlap of individual spectra features prohibits an analysis of the total translation energy spectrum by means of a simple deconvolution procedure. 8 refs., 6 figs.

  18. Heavy quark energy loss in nuclear medium

    International Nuclear Information System (INIS)

    Zhang, Benr-Wei; Wang, Enke; Wang, Xin-Nian

    2003-01-01

    Multiple scattering, modified fragmentation functions and radiative energy loss of a heavy quark propagating in a nuclear medium are investigated in perturbative QCD. Because of the quark mass dependence of the gluon formation time, the medium size dependence of heavy quark energy loss is found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss is also significantly suppressed relative to a light quark due to the suppression of collinear gluon emission by a heavy quark

  19. Equilibration Influence on Jet Energy Loss

    International Nuclear Information System (INIS)

    Cheng Luan; Wang Enke

    2010-01-01

    With the initial conditions in the chemical non-equilibrated medium and Bjorken expanding medium at RHIC, we investigate the consequence for parton evolution. With considering the parton equilibration, we obtain the time dependence of the opacity when the jet propagates through the QGP medium. The parton equilibration affect the jet energy loss with detailed balance evidently. Both parton energy loss from stimulated emission in the chemical non-equilibrated expanding medium and in Bjorken expanding medium are linear dependent on the propagating distance rather than square dependent in the static medium. This will increase the energy and propagating distance dependence of the parton energy loss.

  20. Assessing electron beam sensitivity for SrTiO{sub 3} and La{sub 0.7}Sr{sub 0.3}MnO{sub 3} using electron energy loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nord, Magnus, E-mail: magnunor@gmail.com [Department of Physics, NTNU, Trondheim (Norway); Vullum, Per Erik [Department of Physics, NTNU, Trondheim (Norway); Materials and Chemistry, SINTEF, Trondheim (Norway); Hallsteinsen, Ingrid; Tybell, Thomas [Department of Electronics and Telecommunications, NTNU, Trondheim (Norway); Holmestad, Randi [Department of Physics, NTNU, Trondheim (Norway)

    2016-10-15

    Thresholds for beam damage have been assessed for La{sub 0.7}Sr{sub 0.3}MnO{sub 3} and SrTiO{sub 3} as a function of electron probe current and exposure time at 80 and 200 kV acceleration voltage. The materials were exposed to an intense electron probe by aberration corrected scanning transmission electron microscopy (STEM) with simultaneous acquisition of electron energy loss spectroscopy (EELS) data. Electron beam damage was identified by changes of the core loss fine structure after quantification by a refined and improved model based approach. At 200 kV acceleration voltage, damage in SrTiO{sub 3} was identified by changes both in the EEL fine structure and by contrast changes in the STEM images. However, the changes in the STEM image contrast as introduced by minor damage can be difficult to detect under several common experimental conditions. No damage was observed in SrTiO{sub 3} at 80 kV acceleration voltage, independent of probe current and exposure time. In La{sub 0.7}Sr{sub 0.3}MnO{sub 3}, beam damage was observed at both 80 and 200 kV acceleration voltages. This damage was observed by large changes in the EEL fine structure, but not by any detectable changes in the STEM images. The typical method to validate if damage has been introduced during acquisitions is to compare STEM images prior to and after spectroscopy. Quantifications in this work show that this method possibly can result in misinterpretation of beam damage as changes of material properties. - Highlights: • We studied the effects of a TEM electron beam on a perovskite heterostructure. • Using an improved ELNES quantification method, subtle changes could be observed. • On LSMO changes were observed in the ELNES, but none in the STEM-HAADF. • For STO changes were observed in both ELNES and STEM-HAADF. • This shows beam damage can be misinterpreted as material properties.

  1. The energy cost of quantum information losses

    Science.gov (United States)

    Romanelli, Alejandro; de Lima Marquezino, Franklin; Portugal, Renato; Donangelo, Raul

    2018-05-01

    We explore the energy cost of the information loss resulting from the passage of an initial density operator to a reduced one. We use the concept of entanglement temperature in order to obtain a lower bound for the energy change associated with this operation. We determine the minimal energy required for the case of the information losses associated with the trace over the space coordinates of a two-dimensional quantum walk.

  2. Relativistic energy loss in a dispersive medium

    DEFF Research Database (Denmark)

    Houlrik, Jens Madsen

    2002-01-01

    The electron energy loss in a dispersive medium is obtained using macroscopic electrodynamics taking advantage of a static frame of reference. Relativistic corrections are described in terms of a dispersive Lorentz factor obtained by replacing the vacuum velocity c by the characteristic phase...... velocity c/n, where n is the complex index of refraction. The angle-resolved energy-loss spectrum of a Drude conductor is analyzed in detail and it is shown that the low-energy peak due to Ohmic losses is enhanced compared to the classical approximation....

  3. Deterministic models for energy-loss straggling

    International Nuclear Information System (INIS)

    Prinja, A.K.; Gleicher, F.; Dunham, G.; Morel, J.E.

    1999-01-01

    Inelastic ion interactions with target electrons are dominated by extremely small energy transfers that are difficult to resolve numerically. The continuous-slowing-down (CSD) approximation is then commonly employed, which, however, only preserves the mean energy loss per collision through the stopping power, S(E) = ∫ 0 ∞ dEprime (E minus Eprime) σ s (E → Eprime). To accommodate energy loss straggling, a Gaussian distribution with the correct mean-squared energy loss (akin to a Fokker-Planck approximation in energy) is commonly used in continuous-energy Monte Carlo codes. Although this model has the unphysical feature that ions can be upscattered, it nevertheless yields accurate results. A multigroup model for energy loss straggling was recently presented for use in multigroup Monte Carlo codes or in deterministic codes that use multigroup data. The method has the advantage that the mean and mean-squared energy loss are preserved without unphysical upscatter and hence is computationally efficient. Results for energy spectra compared extremely well with Gaussian distributions under the idealized conditions for which the Gaussian may be considered to be exact. Here, the authors present more consistent comparisons by extending the method to accommodate upscatter and, further, compare both methods with exact solutions obtained from an analog Monte Carlo simulation, for a straight-ahead transport problem

  4. Applications of energy loss contrast STIM

    International Nuclear Information System (INIS)

    Bench, G.; Saint, A.; Legge, G.J.F.; Cholewa, M.

    1992-01-01

    Scanning Transmission Ion Microscopy (STIM) with energy loss contrast is a quantitative imaging technique. A focussed MeV ion microbeam is scanned over the sample and measured energy losses of residual ions at each beam location are used to provide the contrast in the image. The technique is highly efficient as almost every ion carries useful information from which quantitative data can be obtained. The high efficiency of data collection at present necessitates the use of small beam currents. Therefore small apertures can be used and fine spatial resolution can be achieved. High efficiency also makes it possible to collect large data sets for high definition imaging with a small radiation dose. Owing to the simple relationship between energy loss and areal density, STIM with energy loss contrast can provide a quantitative image that can be used to obtain areal density information on the sample. These areal density maps can be used not only to provide a high resolution image of the sample but also to normalise Particle Induced Xray Emission (PIXE) data. The small radiation dose required to form these areal density maps also allows one to use STIM with energy loss contrast to quantitatively monitor ion beam induced specimen changes caused by higher doses and dose rates used in other microanalytical techniques. STIM with energy loss contrast also provides the possibility of stereo imaging and ion microtomography. STIM has also been used in conjunction with channeling to explore transmission channeling in thin crystals. This paper will discuss these applications of STIM with energy loss contrast and look at further developments from them

  5. Energy analyzer for Auger electron spectroscopy and low-energy backscattering ion spectroscopy

    International Nuclear Information System (INIS)

    Volkov, S.S.; Gorelik, V.A.; Gutenko, V.T.; Protopopov, O.D.; Trubitsin, A.A.; Shuvalova, Z.A.; Yakushev, G.A.

    1988-01-01

    Energy analyzer for electron Auger spectroscopy and low-energy backscattering ion spectroscopy is described. Analyzer presents one-cascade variant of cylindrical mirror with second-order focusing. Energy relative resolution is continuously adjusted within 0.2-1.2% limits. Signal/noise relation by Cu Auger-line at 1 muA current of exciting beam changes upper limit of range 150-450

  6. Calculated and experimental low-loss electron energy loss spectra of dislocations in diamond and GaN

    CERN Document Server

    Jones, R; Gutiérrez-Sosa, A; Bangert, U; Heggie, M I; Blumenau, A T; Frauenheim, T; Briddon, P R

    2002-01-01

    First-principles calculations of electron energy loss (EEL) spectra for bulk GaN and diamond are compared with experimental spectra acquired with a scanning tunnelling electron microscope offering ultra-high-energy resolution in low-loss energy spectroscopy. The theoretical bulk low-loss EEL spectra, in the E sub g to 10 eV range, are in good agreement with experimental data. Spatially resolved spectra from dislocated regions in both materials are distinct from bulk spectra. The main effects are, however, confined to energy losses lying above the band edge. The calculated spectra for low-energy dislocations in diamond are consistent with the experimental observations, but difficulties remain in understanding the spectra of threading dislocations in GaN.

  7. Microgrids: Energy management by loss minimization technique

    Energy Technology Data Exchange (ETDEWEB)

    Basu, A.K. [Electrical Engineering Dept., Jadavpur University & 20/2, Khanpur Road, Kolkata 700047 (India); Chowdhury, S.; Chowdhury, S.P. [Electrical Engineering Department, University of Cape Town & Private Bag X3, Menzies Building, Room-517, Rondebosch, Cape Town 7701 (India)

    2011-07-01

    Energy management is a techno-economic issue, which dictates, in the context of microgrids, how optimal investment in technology front could bring optimal power quality and reliability (PQR) of supply to the consumers. Investment in distributed energy resources (DERs), with their connection to the utility grid at optimal locations and with optimal sizes, saves energy in the form of line loss reduction. Line loss reduction is the indirect benefit to the microgrid owner who may recover it as an incentive from utility. The present paper focuses on planning of optimal siting and sizing of DERs based on minimization of line loss. Optimal siting is done, here, on the loss sensitivity index (LSI) method and optimal sizing by differential evolution (DE) algorithms, which is, again, compared with particle swarm optimization (PSO) technique. Studies are conducted on 6-bus and 14-bus radial networks under islanded mode of operation with electric demand profile. Islanding helps planning of DER capacity of microgrid, which is self-sufficient to cater its own consumers without utility's support.

  8. Turbulent energy losses during orchard heating

    Energy Technology Data Exchange (ETDEWEB)

    Bland, W.L.

    1979-01-01

    Two rapid-response drag anemometers and low time constant thermocouples, all at 4 m above a heated orchard floor, sampled wind component in the vertical direction and temperature at 30 Hz. The turbulent heat flux calculated revealed not more than 10% of the heat lost from the orchard was via turbulent transort. The observations failed to support previous estimates that at least a third of the energy applied was lost through turbulent transport. Underestimation of heat loss due to mean flow and a newly revealed flux due to spatial variations in the mean flow may explain the unaccounted for loss.

  9. Estimation of fluctuation in restricted energy loss

    International Nuclear Information System (INIS)

    Doke, T.; Hayashi, T.; Nagata, K.

    1983-01-01

    Restricted Energy Loss (REL) is defined as an energy loss [(dE/dX)/sub E//sub delta/<ν/] that produced the delta-rays of energies less than some specified energy ν and is often used as a simple measure of track structure. For example, REL is a measure of track formation threshold in plastic track detector and the growth rate of track in chemical etching solution is considered to depend only on REL given along the track. Using a stack of elastic sheets, recently, it became possible to identify isotopes of incident particles. In that case, the limit of mass resolution is determined by fluctuation of REL in the length of etch pit produced along the path of particle. A computer program was developed to calculate the probability distribution for energy deposition in absorber allowing for electron escape. In this calculation, it is assumed that all electrons with energies greater than a certain value epsilon/sub d/ escape. This means that this calculation directly gives the fluctuation of REL. Therefore, we tried to use the computer program to estimate the ultimate mass resolution in plastic detector. In this paper, we show firstly the comparison of ASB's calculation with the experimental results obtained by a gas counter and next the results of estimation of ultimate mass resolution in plastic detectors

  10. Coherence in electron energy loss spectrometry

    International Nuclear Information System (INIS)

    Schattschneider, P.; Werner, W.S.M.

    2005-01-01

    Coherence effects in electron energy loss spectrometry (EELS) and in energy filtering are largely neglected although they occur frequently due to Bragg scattering in crystals. We discuss how coherence in the inelastically scattered wave field can be described by the mixed dynamic form factor (MDFF), and how it relates to the density matrix of the scattered electrons. Among the many aspects of 'inelastic coherence' are filtered high-resolution images, dipole-forbidden transitions, coherence in plasma excitations, errors in chemical microanalysis, coherent double plasmons, and circular dichroism

  11. Electron spectroscopy

    International Nuclear Information System (INIS)

    Hegde, M.S.

    1979-01-01

    An introduction to the various techniques in electron spectroscopy is presented. These techniques include: (1) UV Photoelectron spectroscopy, (2) X-ray Photoelectron spectroscopy, (3) Auger electron spectroscopy, (4) Electron energy loss spectroscopy, (5) Penning ionization spectroscopy and (6) Ion neutralization spectroscopy. The radiations used in each technique, the basis of the technique and the special information obtained in structure determination in atoms and molecules by each technique are summarised. (A.K.)

  12. Energy-loss return gate via liquid dielectric polarization.

    Science.gov (United States)

    Kim, Taehun; Yong, Hyungseok; Kim, Banseok; Kim, Dongseob; Choi, Dukhyun; Park, Yong Tae; Lee, Sangmin

    2018-04-12

    There has been much research on renewable energy-harvesting techniques. However, owing to increasing energy demands, significant energy-related issues remain to be solved. Efforts aimed at reducing the amount of energy loss in electric/electronic systems are essential for reducing energy consumption and protecting the environment. Here, we design an energy-loss return gate system that reduces energy loss from electric/electronic systems by utilizing the polarization of liquid dielectrics. The use of a liquid dielectric material in the energy-loss return gate generates electrostatic potential energy while reducing the dielectric loss of the electric/electronic system. Hence, an energy-loss return gate can make breakthrough impacts possible by amplifying energy-harvesting efficiency, lowering the power consumption of electronics, and storing the returned energy. Our study indicates the potential for enhancing energy-harvesting technologies for electric/electronics systems, while increasing the widespread development of these systems.

  13. New approach to energy loss measurements

    CERN Document Server

    Trzaska, W H; Alanko, T; Mutterer, M; Raeisaenen, J; Tjurin, G; Wojdyr, M

    2002-01-01

    A new approach to energy loss measurements is proposed. In the same experiment electronic stopping force (power) in gold, nickel, carbon, polycarbonate and Havar for sup 4 sup 0 Ar, sup 2 sup 8 Si, sup 1 sup 6 O, sup 4 He and sup 1 H ions in the energy range 0.12-11 MeV/u has been measured. In this paper we give the full results for gold, nickel, and carbon and for sup 4 sup 0 Ar, sup 1 sup 6 O, sup 4 He and sup 1 H ions. Good agreement of the measured stopping force values for light ions with literature data is interpreted as the positive test of the experimental technique. The same technique used with heavy ions yields agreement with the published data only for energies above 1 MeV/u. At lower energies we observe progressively increasing discrepancy. This discrepancy is removed completely as soon as we neglect pulse height defect compensation. This observation makes us believe that the majority of the published results as well as semi-empirical calculations based on them (like the popular SRIM) may be in er...

  14. Optimal Allocation of Renewable Energy Sources for Energy Loss Minimization

    Directory of Open Access Journals (Sweden)

    Vaiju Kalkhambkar

    2017-03-01

    Full Text Available Optimal allocation of renewable distributed generation (RDG, i.e., solar and the wind in a distribution system becomes challenging due to intermittent generation and uncertainty of loads. This paper proposes an optimal allocation methodology for single and hybrid RDGs for energy loss minimization. The deterministic generation-load model integrated with optimal power flow provides optimal solutions for single and hybrid RDG. Considering the complexity of the proposed nonlinear, constrained optimization problem, it is solved by a robust and high performance meta-heuristic, Symbiotic Organisms Search (SOS algorithm. Results obtained from SOS algorithm offer optimal solutions than Genetic Algorithm (GA, Particle Swarm Optimization (PSO and Firefly Algorithm (FFA. Economic analysis is carried out to quantify the economic benefits of energy loss minimization over the life span of RDGs.

  15. Energy Loss of Coasting Gold Ions and Deuterons in RHIC

    CERN Document Server

    Abreu, N P; Brown, K; Burkhardt, H; Butler, J; Fischer, W; Harvey, M; Tepikian, S

    2008-01-01

    The total energy loss of coasting gold ion beams at two different energies and deuterons at one energy were measured at RHIC, corresponding to a gamma of 75.2, 107.4 and 108.7 respectively. We describe the experiment and observations and compare the measured total energy loss with expectations from ionization losses at the residual gas, the energy loss due to impedance and synchrotron radiation. We find that the measured energy losses are below what is expected from free space synchrotron radiation. We believe that this shows evidence for suppression of synchrotron radiation which is cut off at long wavelength by the presence of the conducting beam pipe.

  16. Implementing tactical plans to improve water-energy loss management

    OpenAIRE

    Loureiro, D.; Alegre, H.; Silva, M. S.; Ribeiro, R.; Mamade, A.; Poças, A.

    2015-01-01

    Water utilities are aware of the water-energy loss relevance in supply systems. However, they still mainly focus on daily water loss control (real and apparent losses), without considering the impact on embedded energy. Moreover, they are mostly concerned with the economic dimension and, in most cases, tend to disregard the impact that water-energy loss may have on the quality of service, communication with the customers, social awareness, water quality and environment. This paper focuses on ...

  17. Modelling high-resolution electron microscopy based on core-loss spectroscopy

    International Nuclear Information System (INIS)

    Allen, L.J.; Findlay, S.D.; Oxley, M.P.; Witte, C.; Zaluzec, N.J.

    2006-01-01

    There are a number of factors affecting the formation of images based on core-loss spectroscopy in high-resolution electron microscopy. We demonstrate unambiguously the need to use a full nonlocal description of the effective core-loss interaction for experimental results obtained from high angular resolution electron channelling electron spectroscopy. The implications of this model are investigated for atomic resolution scanning transmission electron microscopy. Simulations are used to demonstrate that core-loss spectroscopy images formed using fine probes proposed for future microscopes can result in images that do not correspond visually with the structure that has led to their formation. In this context, we also examine the effect of varying detector geometries. The importance of the contribution to core-loss spectroscopy images by dechannelled or diffusely scattered electrons is reiterated here

  18. Energy-loss measurements with heavy ions at relativistic energies

    International Nuclear Information System (INIS)

    Blank, B.; Gaimard, J.J.; Geissel, H.; Muenzenberg, G.; Schmidt, K.H.; Stelzer, H.; Suemmerer; Clerc, H.G.; Hanelt, E.; Steiner, M.; Voss, B.

    1990-03-01

    Using the magnetic spectrometer SPES I at SATURNE, energy-loss measurements have been performed for projectiles of 40 Ar (401 MeV/u), 36 P (362 MeV/u), 15 N (149 MeV/u), 11 Li (131 MeV/u) and 8 Li, 9 Li (130 MeV/u) in carbon, aluminum and lead targets. The experimental results are compared to calculations based on a modified relativistic Bethe formula and to a semi-empirical formula using a Z 2 scaling law for the stopping power and an effective charge parametrization for the heavy ions. (orig.)

  19. Two types of charge transfer excitations in low dimensional cuprates: an electron energy-loss study

    Czech Academy of Sciences Publication Activity Database

    Knupfer, M.; Fink, J.; Drechsler, S.-L.; Hayn, R.; Málek, Jiří; Moskvin, A.S.

    137-140, - (2004), s. 469-473 ISSN 0368-2048 Institutional research plan: CEZ:AV0Z1010914 Keywords : cuprates * electronic excitations * electron energy-loss spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.069, year: 2004

  20. High energy resolution off-resonant X-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wojciech, Blachucki [Univ. of Fribourg (Switzerland). Dept. of Physics

    2015-10-16

    This work treats of the high energy resolution off-resonant X-ray spectroscopy (HEROS) method of determining the density of unoccupied electronic states in the vicinity of the absorption edge. HEROS is an alternative to the existing X-ray absorption spectroscopy (XAS) methods and opens the way for new studies not achievable before.

  1. Local energy losses at positive and negative steps in subcritical ...

    African Journals Online (AJOL)

    Local energy losses occur when there is a transition in open channel flow. Even though local losses in subcritical open channel flow due to changes in channel width have been studied, to date no studies have been reported for losses due to changes in bed elevations. Steps are commonly used in engineering applications ...

  2. Energy losses of superconducting power transmission cables in the grid

    DEFF Research Database (Denmark)

    Østergaard, Jacob; Okholm, Jan; Lomholt, Karin

    2001-01-01

    One of the obvious motives for development of superconducting power transmission cables is reduction of transmission losses. Loss components in superconducting cables as well as in conventional cables have been examined. These losses are used for calculating the total energy losses of conventional...... as well as superconducting cables when they are placed in the electric power transmission network. It is concluded that high load connections are necessary to obtain energy saving by the use of HTSC cables. For selected high load connections, an energy saving of 40% is expected. It is shown...

  3. Energy-dependent losses in pulsed-feedback preamplifiers

    International Nuclear Information System (INIS)

    Landis, D.A.; Madden, N.W.; Goulding, F.S.

    1978-11-01

    Energy dependent counting losses occur in most pulsed-feedback preamplifiers due to the loss of those pulses which activate the recharge system. A pulsed-feedback system that overcomes this inefficiency is described. Pulsed-light feedback as used with germanium gamma-ray spectrometers is discussed as used at high energies and high rates where those losses become significant. Experimental results are presented

  4. Characteristic electron energy losses in monoatomic antimony films on (110) and (112) tungsten faces

    International Nuclear Information System (INIS)

    Gorodetskij, D.A.; Gorchinskij, A.D.; Shevlyakov, S.A.

    1981-01-01

    Complex investigations of antimony condensation on a monoatomical clean surface of tungsten monocrystals are carried out. The completion of a physical antimony monolayer has been controlled by the methods of Auger-electron spectroscopy and slow electron diffraction. It is shown that at submonolayer coatings a collectivization of valent electrons occurs leading to appearance of peaks of surface and volumetric plasmons in the energy losses spectrum. The anomalous cencentrational dependence of antimony ionization peak intensity has been found. The origin of previously unexplored peaks in the energy losses spectrum is discussed [ru

  5. Elucidating Jet Energy Loss Using Jets Prospects from ATLAS

    CERN Document Server

    Grau, N

    2009-01-01

    Jets at the LHC are expected to provide the testing ground for studying QCD energy loss. In this contribution, we briefly outline the strategy that will be used to measure jets in ATLAS and how we will go about studying energy loss. We describe the utility of measuring the jet $R_{AA}$, the fragmentation function, and heavy flavor jets. Utilizing the collision energy provided by the LHC and the nearly hermetic and highly segmented calorimeter, ATLAS is expected to make important contributions to the understanding of parton energy loss using fully reconstructed jets.

  6. Elucidating Jet Energy Loss Using Jets: Prospects from ATLAS

    International Nuclear Information System (INIS)

    Grau, N.

    2009-01-01

    Jets at the LHC are expected to provide the testing ground for studying QCD energy loss. In this contribution, we briefly outline the strategy that will be used to measure jets in ATLAS and how we will go about studying energy loss. We describe the utility of measuring the jet R AA , the fragmentation function, and heavy flavor jets. Utilizing the collision energy provided by the LHC and the nearly hermetic and highly segmented calorimeter, ATLAS is expected to make important contributions to the understanding of parton energy loss using fully reconstructed jets.

  7. Energy loss of charged particles to molecular gas targets

    International Nuclear Information System (INIS)

    Sigmund, P.

    1976-01-01

    The energy loss spectrum of fast charged particles penetrating a dilute molecular gas target has been analysed theoretically, with a homogeneous gas mixture in the state of complete dissociation as a reference standard. It is shown that the geometrical structure of molecules causes the energy-loss straggling and higher moments over the energy-loss spectrum to be greater than the corresponding quantities for a completely dissociated gas of equal composition. Such deviations from additivity are shown to be most pronounced at energies around the stopping-power maximum. There is found supporting evidence in the experimental literature. (Auth.)

  8. Energy loss in grazing proton-surface collisions

    Energy Technology Data Exchange (ETDEWEB)

    Juaristi, J I [Dept. Fisica de Materiales, Facultad de Quimicas, UPV/EHU, San Sebastian (Spain); Garcia de Abajo, F J [Dept. Ciencias de la Computacion e Inteligencia Artificial, Facultad de Informatica, UPV/EHU, San Sebastian (Spain)

    1994-05-01

    The energy loss of fast protons, with energy E > 100 keV, specularly reflected on a solid surface with glancing angle of incidence of the order of a mrad is analysed on theoretical grounds. Two different contributions can be distinguished: (i) energy losses originating from the interaction with the valence band, accounted for through an induced force, and (ii) the excitation of electron bound states of the target atoms. The results are compared with available experimental data. (orig.)

  9. Performance of the electron energy-loss spectrometer

    International Nuclear Information System (INIS)

    Tanaka, H.; Huebner, R.H.

    1977-01-01

    Performance characteristics of the electron energy-loss spectrometer incorporating a new high-resolution hemispherical monochromator are reported. The apparatus achieved an energy-resolution of 25 meV in the elastic scattering mode, and angular distributions of elastically scattered electrons were in excellent agreement with previous workers. Preliminary energy-loss spectra for several atmospheric gases demonstrate the excellent versatility and stable operation of the improved system. 12 references

  10. Energy loss in grazing proton-surface collisions

    International Nuclear Information System (INIS)

    Juaristi, J.I.; Garcia de Abajo, F.J.

    1994-01-01

    The energy loss of fast protons, with energy E > 100 keV, specularly reflected on a solid surface with glancing angle of incidence of the order of a mrad is analysed on theoretical grounds. Two different contributions can be distinguished: i) energy losses originating from the interaction with the valence band, accounted for through an induced force, and ii) the excitation of electron bound states of the target atoms. The results are compared with available experimental data. (orig.)

  11. Electron energy-loss spectrometry at the frontier of spatial and energy resolution

    International Nuclear Information System (INIS)

    Hofer, F.; Grogger, W.; Kothleitner, G.

    2004-01-01

    Full text: Electron energy-loss spectroscopy (EELS) in the transmission electron microscope (TEM) is now used routinely as a means of measuring chemical and structural properties of very small regions of a thin specimen. The power of this technique depends significantly on two parameters: its spatial resolution and the energy resolution available in the spectrum and in the energy-filtered TEM (EFTEM) image. The cold field emission source and the Schottky emitter have made an energy resolution below 1 eV possible and it is now feasible to obtain data with a spatial resolution close to atomic dimensions, given the right instrumentation and specimen. EFTEM allows to record elemental maps at sub-nanometre resolution, being mainly limited by chromatic and spherical aberration of the objective lens and by delocalization of inelastic scattering. Recently the possibility of correcting spherical and even chromatic aberrations of electron lenses has become a practical reality thus improving the point resolution of the TEM to below 0.1 nm. The other limiting factor for EFTEM resolution is delocalization. However, recent measurements show that resolution values in the range of 1 nm and below can be achieved, even for energy-losses of only a few eV. In terms of energy-resolution, EELS and EFTEM compare less favourably with other spectroscopies. For common TEMs, the overall energy-resolution is mainly determined by the energy width of the electron source, typically between 0.5 and 1.5 eV. For comparison, synchrotron x-ray sources and beam line spectrometers, provide a resolution well below 0.1 eV for absorption spectroscopy. During the early sixties, the energy spread of an electron beam could be reduced by incorporating an energy-filter into the illumination system, but the system lacked spatial resolution. Later developments combined high energy resolution in the range of 0.1 eV with improved spatial resolution. Recently, FEI introduced a new high resolution EELS system based

  12. Proton energy loss in multilayer graphene and carbon nanotubes

    Science.gov (United States)

    Uribe, Juan D.; Mery, Mario; Fierro, Bernardo; Cardoso-Gil, Raul; Abril, Isabel; Garcia-Molina, Rafael; Valdés, Jorge E.; Esaulov, Vladimir A.

    2018-02-01

    Results of a study of electronic energy loss of low keV protons interacting with multilayer graphene targets are presented. Proton energy loss shows an unexpectedly high value as compared with measurements in amorphous carbon and carbon nanotubes. Furthermore, we observe a classical linear behavior of the energy loss with the ion velocity but with an apparent velocity threshold around 0.1 a.u., which is not observed in other carbon allotropes. This suggests low dimensionality effects which can be due to the extraordinary graphene properties.

  13. Energy-modulation spectroscopy in hard X-ray region

    CERN Document Server

    Suzuki, M; Ishikawa, T

    2001-01-01

    An energy-modulation technique has been developed for XAFS spectroscopies requiring high energy resolution and high precision. Fast energy switching at 40 Hz has been achieved by adopting a Si channel-cut crystal as a second monochromator together with a piezo-driven oscillation stage, and the resulting variation in sample absorption was detected using an amplifier locked to the energy-modulation frequency. An energy-derivative XAFS spectrum was directly obtained at the Mn K-edge, and illustrated the advantages of this technique in high energy resolution and noise reduction.

  14. Measurements of energy losses, distributions of energy loss and additivity of energy losses for 50 to 150 keV protons in hydrogen and nine hydrocarbon gases

    International Nuclear Information System (INIS)

    Thorngate, J.H.

    1976-05-01

    Measurements of energy-loss distributions were made for 51, 102, and 153 keV protons traversing hydrogen, methane, ethyne (acetylene), ethene (ethylene), ethane, propyne (methyl acetylene), propadiene (allene), propene (propylene), cyclopropane and propane. The objectives were to test the theories of energy-loss distribution in this energy range and to see if the type of carbon bonding in a hydrocarbon molecule affects the shape of the distribution. Stopping powers and stopping cross sections were also measured at these energies and at 76.5 and 127.5 keV to determine effects of chemical binding. All of the measurements were made at the gas density required to give a 4 percent energy loss. The mean energy, second central moment (a measure of the width of the distribution), and the third central moment (a measure of the skew) were calculated from the measured energy-loss distributions. Stopping power values, calculated using the mean energy, compared reasonably well with those calculated from the Bethe stopping power theory. For the second and third central moments, the best agreement between measurement and theory was when the classical scattering probability was used for the calculations, but even these did not agree well. In all cases, variations were found in the data that could be correlated to the type of carbon binding in the molecule. The differences were statistically significant at a 99 percent confidence interval for the stopping powers and second central moments measured with 51 keV protons. Similar trends were noted at other energies and for the third central moment, but the differences were not statistically significant at the 99 percent confidence interval

  15. Holographic energy loss in non-relativistic backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Atashi, Mahdi; Fadafan, Kazem Bitaghsir; Farahbodnia, Mitra [Shahrood University of Technology, Physics Department, P.O. Box 3619995161, Shahrood (Iran, Islamic Republic of)

    2017-03-15

    In this paper, we study some aspects of energy loss in non-relativistic theories from holography. We analyze the energy lost by a rotating heavy point particle along a circle of radius l with angular velocity ω in theories with general dynamical exponent z and hyperscaling violation exponent θ. It is shown that this problem provides a novel perspective on the energy loss in such theories. A general computation at zero and finite temperature is done and it is shown how the total energy loss rate depends non-trivially on two characteristic exponents (z,θ). We find that at zero temperature there is a special radius l{sub c} where the energy loss is independent of different values of (θ,z). Also at zero temperature, there is a crossover between a regime in which the energy loss is dominated by the linear drag force and by the radiation because of the acceleration of the rotating particle. We find that the energy loss of the particle decreases by increasing θ and z. We note that, unlike in the zero temperature, there is no special radius l{sub c} at finite temperature case. (orig.)

  16. Characteristic electron energy loss spectra in SiC buried layers formed by C+ implantation into crystalline silicon

    International Nuclear Information System (INIS)

    Yan Hui; Chen Guanghua; Kwok, R.W.M.

    1998-01-01

    SiC buried layers were synthesized by a metal vapor vacuum arc ion source, with C + ions implanted into crystalline Si substrates. According to X-ray photoelectron spectroscopy, the characteristic electron energy loss spectra of the SiC buried layers were studied. It was found that the characteristic electron energy loss spectra depend on the profiles of the carbon content, and correlate well with the order of the buried layers

  17. Experimental investigation of energy loss and end loss physics in a linear theta pinch. Scientific report 81-3

    International Nuclear Information System (INIS)

    Jacoby, B.A.

    1981-01-01

    The results of an experimental study of particle and thermal loss processes from a 50-cm long theta pinch are presented. The plasma was generated with a 40-mTorr fill of deuterium in a 3.81 cm radius discharge tube; 67% Z-preionization was followed by a main current discharge that produced a 23-kG peak magnetic field in 4.75 μsec. The electron density and temperature in the plasma column at the end of dynamic implosion were characterized by 1.0 x 10 16 cm -3 and 20 eV, respectively. This was followed by adiabatic compression which occurred with the particle and energy loss of interest. The diagnostics employed in this experiment were Thomson scattering, continuum radiation spectroscopy, local magnetic-field probes, local pressure probes, and diamagnetic loops. Axial temperature and density profiles were mapped from the coil into the end region

  18. Kramers-Kronig transform for the surface energy loss function

    International Nuclear Information System (INIS)

    Tan, G.L.; DeNoyer, L.K.; French, R.H.; Guittet, M.J.; Gautier-Soyer, M.

    2005-01-01

    A new pair of Kramers-Kronig (KK) dispersion relationships for the transformation of surface energy loss function Im[-1/(ε + 1)] has been proposed. The validity of the new surface KK transform is confirmed, using both a Lorentz oscillator model and the surface energy loss functions determined from the experimental complex dielectric function of SrTiO 3 and tungsten metal. The interband transition strength spectra (J cv ) have been derived either directly from the original complex dielectric function or from the derived dielectric function obtained from the KK transform of the surface energy loss function. The original J cv trace and post-J cv trace overlapped together for the three modes, indicating that the new surface Kramers-Kronig dispersion relationship is valid for the surface energy loss function

  19. Local energy losses at positive and negative steps in subcritical ...

    African Journals Online (AJOL)

    2010-04-22

    Apr 22, 2010 ... channel flow due to changes in channel width have been studied, to date no studies have been reported for losses due to changes in bed elevations. .... of these studies report on numerical modelling of flow over transitions. ... that the frictional losses are negligible, the energy equation between Sections (1) ...

  20. Model calculation for energy loss in ion-surface collisions

    International Nuclear Information System (INIS)

    Miraglia, J.E.; Gravielle, M.S.

    2003-01-01

    The so-called local plasma approximation is generalized to deal with projectiles colliding with surfaces of amorphous solids and with a specific crystalline structure (plannar channeling). Energy loss of protons grazingly colliding with aluminum, SnTe alloy, and LiF surfaces is investigated. The calculations agree quite well with previous theoretical results and explain the experimental findings of energy loss for aluminum and SnTe alloy, but they fall short to explain the data for LiF surfaces

  1. Intruder states and low energy nuclear spectroscopy

    International Nuclear Information System (INIS)

    Bengtsson, R.

    1991-01-01

    The crucial role intruder orbitals play is not limited to low spin and small deformations. In fact much of the physics at superdeformed shapes and at very high spin is a direct result of the presence of high-j intruder orbitals in the vicinity of the Fermi surface, including the introduction of intruder orbitals from still higher shells at extreme deformations. Since the intruder subshell has a larger angular momentum (j) than any other subshell close to the Fermi surface it plays an essential role for building up angular momentum in the nucleus, and the alignment of intruder shell (quasi) particles is responsible for a large variety of bandcrossings observed in discrete spectroscopy along or near the yrast line. Intruder shell orbitals are also associated with large quadrupole moments and the occupation of these orbitals may lead to significant changes of the deformation of the nucleus. Under favorable circumstances a nucleus may have totally different shapes depending on the occupation of the intruder orbitals, giving rise to a phenomenon which is usually referred to as shape coexistence. In this paper, shape coexistence in several mass regions will be discussed with specific attention focused on the relation between shape coexistence and the occupation of intruder shell levels. Shape effects associated both with spin aligned and non-aligned intruder orbitals will be investigated

  2. Measuring Intermolecular Binding Energies by Laser Spectroscopy.

    Science.gov (United States)

    Knochenmuss, Richard; Maity, Surajit; Féraud, Géraldine; Leutwyler, Samuel

    2017-02-22

    The ground-state dissociation energy, D0(S0), of isolated intermolecular complexes in the gas phase is a fundamental measure of the interaction strength between the molecules. We have developed a three-laser, triply resonant pump-dump-probe technique to measure dissociation energies of jet-cooled M•S complexes, where M is an aromatic chromophore and S is a closed-shell 'solvent' molecule. Stimulated emission pumping (SEP) via the S0→S1 electronic transition is used to precisely 'warm' the complex by populating high vibrational levels v" of the S0 state. If the deposited energy E(v") is less than D0(S0), the complex remains intact, and is then mass- and isomer-selectively detected by resonant two-photon ionization (R2PI) with a third (probe) laser. If the pumped level is above D0(S0), the hot complex dissociates and the probe signal disappears. Combining the fluorescence or SEP spectrum of the cold complex with the SEP breakoff of the hot complex brackets D0(S0). The UV chromophores 1-naphthol and carbazole were employed; these bind either dispersively via the aromatic rings, or form a hydrogen bond via the -OH or -NH group. Dissociation energies have been measured for dispersively bound complexes with noble gases (Ne, Kr, Ar, Xe), diatomics (N2, CO), alkanes (methane to n-butane), cycloalkanes (cyclopropane to cycloheptane), and unsaturated compounds (ethene, benzene). Hydrogen-bond dissociation energies have been measured for H2O, D2O, methanol, ethanol, ethers (oxirane, oxetane), NH3 and ND3.

  3. Energy-gap spectroscopy of superconductors using a tunneling microscope

    International Nuclear Information System (INIS)

    Le Duc, H.G.; Kaiser, W.J.; Stern, J.A.

    1987-01-01

    A unique scanning tunneling microscope (STM) system has been developed for spectroscopy of the superconducting energy gap. High-resolution control of tunnel current and voltage allows for measurement of superconducting properties at tunnel resistance levels 10 2 --10 3 greater than that achieved in prior work. The previously used STM methods for superconductor spectroscopy are compared to those developed for the work reported here. Superconducting energy-gap spectra are reported for three superconductors, Pb, PbBi, and NbN, over a range of tunnel resistance. The measured spectra are compared directly to theory

  4. Radiative energy loss of neighboring subjets arXiv

    CERN Document Server

    Mehtar-Tani, Yacine

    We compute the in-medium energy loss probability distribution of two neighboring subjets at leading order, in the large-$N_c$ approximation. Our result exhibits a gradual onset of color decoherence of the system and accounts for two expected limiting cases. When the angular separation is smaller than the characteristic angle for medium-induced radiation, the two-pronged substructure lose energy coherently as a single color charge, namely that of the parent parton. At large angular separation the two subjets lose energy independently. Our result is a first step towards quantifying effects of energy loss as a result of the fluctuation of the multi-parton jet substructure and therefore goes beyond the standard approach to jet quenching based on single parton energy loss. We briefly discuss applications to jet observables in heavy-ion collisions.

  5. Photoelectron energy-loss study of the Bi2CaSr2Cu2O8 superconductor

    International Nuclear Information System (INIS)

    Shen, Z.; Lindberg, P.A.P.; Dessau, D.S.; Lindau, I.; Spicer, W.E.; Mitzi, D.B.; Bozovic, I.; Kapitulnik, A.

    1989-01-01

    Using energy-loss spectroscopy of photoelectrons from a single crystal of Bi 2 CaSr 2 Cu 2 O 8 , we show that the electronic structure of the near-surface region is the same as that of the bulk. Utilizing the fact that photoelectrons of different elements are excited at different locations in the unit cell, we identify the energy-loss features as due to valence plasmon excitations, and one-electron excitations by comparing the photoelectron energy-loss spectra of the different elements

  6. LENS spectroscopy of low energy solar neutrinos

    CERN Document Server

    Schönert, S

    2001-01-01

    The LENS experiments will measure energy resolved sub-MeV solar electron-neutrinos ( nu /sub e/) in real time via inverse beta - transition populating an isomeric state in the daughter nuclei. The subsequent de-excitation provides a delayed coincidence tag which discriminates against background. A liquid scintillation detector loaded with 20 t of Yb would yield an event rate of 190 pp- and 175 /sup 7/Be neutrinos per year. Essential information on neutrino mixing and masses can be derived.

  7. Low energy nuclear spin excitations in Ho metal investigated by high resolution neutron spectroscopy.

    Science.gov (United States)

    Chatterji, Tapan; Jalarvo, Niina

    2013-04-17

    We have investigated the low energy excitations in metallic Ho by high resolution neutron spectroscopy. We found at T = 3 K clear inelastic peaks in the energy loss and energy gain sides, along with the central elastic peak. The energy of this low energy excitation, which is 26.59 ± 0.02 μeV at T = 3 K, decreased continuously and became zero at TN ≈ 130 K. By fitting the data in the temperature range 100-127.5 K with a power law we obtained the power-law exponent β = 0.37 ± 0.02, which agrees with the expected value β = 0.367 for a three-dimensional Heisenberg model. Thus the energy of the low energy excitations can be associated with the order parameter.

  8. Comments on GUT monopole energy loss and ionization

    International Nuclear Information System (INIS)

    Hagstrom, R.

    1982-01-01

    A few comments about the likely behavior of the electromagnetic energy loss and ionization rates of super-slowly moving magnetic monopoles are presented. The questions of energy loss rates and ionization rates for super-low monopoles passing through matter are considered, concentrating on aspects of these issues which affect practical detection techniques. It is worthwhile here to emphasize that there is a potentially great distinction between energy loss rates and ionization rates and that the magnitude of this distinction is really the great issue which must be settled in order to understand the significance of experimental results from present and proposed investigations of the slow monopole question. Energy loss here means the total dE/dX of the projectile due to interactions with the electrons of the slowing medium. To the extent that nuclear collisions can be neglected, this so-called electronic energy loss is the relevant quantity in questions about whether monopoles stop within the earth's crust, whether they are slowed by interstellar plasmas, or the signal in a truly calorimetric measurement (measuring temperature rises along the trajectory), etc. Most of our successful detection techniques depend upon the promotion of ground state electrons into states which lie above some energy gap in the material of the detector: electrons must be knocked completely free from the gas atoms in a proportional chamber gas, electrons must be promoted to a higher band in solid scintillator plastics. These processes are generically identified as ionization

  9. Construction of energy loss function for low-energy electrons in helium

    Energy Technology Data Exchange (ETDEWEB)

    Dayashankar, [Bhabha Atomic Research Centre, Bombay (India). Div. of Radiation Protection

    1976-02-01

    The energy loss function for electrons in the energy range from 50 eV to 1 keV in helium gas has been constructed by considering separately the energy loss in overcoming the ionization threshold, the loss manifested as kinetic energy of secondary electrons and the loss in the discrete state excitations. This has been done by utilizing recent measurements of Opal et al. on the energy spectrum of secondary electrons and incorporating the experimental data on cross sections for twenty-four excited states. The present results of the energy loss function are in good agreement with the Bethe formula for energies above 500 eV. For lower energies, where the Bethe formula is not applicable, the present results should be particularly useful.

  10. Energy- and angled-resolved photoelectron spectroscopy of negative ions

    International Nuclear Information System (INIS)

    Pegg, D.J.; Thompson, J.S.; Compton, R.N.; Alton, G.D.

    1988-01-01

    Energy- and angle-resolved photoelectron detachment spectroscopy is currently being used to investigate the structure of negative ions and their interaction with radiation. Measurements of the electron affinity of the Ca atom and the partial cross sections for photodetachment of the metastable negative ion, He - (1s2s2p 4 P), are reported. 5 refs., 5 figs

  11. Energy-Efficiency Options for Insurance Loss Prevention

    Energy Technology Data Exchange (ETDEWEB)

    Mills, E. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States). Environmental Energy Technologies Div.; Knoepfel, I. [Swiss Reinsurance Co., Zurich (Switzerland)

    1997-06-09

    Energy-efficiency improvements offer the insurance industry two areas of opportunity: reducing ordinary claims and avoiding greenhouse gas emissions that could precipitate natural disaster losses resulting from global climate change. We present three vehicles for taking advantage of this opportunity, including research and development, in- house energy management, and provision of key information to insurance customers and risk managers. The complementary role for renewable energy systems is also introduced.

  12. Electron energy-loss spectroscopy of branched gap plasmon resonators

    DEFF Research Database (Denmark)

    Raza, Søren; Esfandyarpour, Majid; Koh, Ai Leen

    2016-01-01

    The miniaturization of integrated optical circuits below the diffraction limit for high-speed manipulation of information is one of the cornerstones in plasmonics research. By coupling to surface plasmons supported on nanostructured metallic surfaces, light can be confined to the nanoscale, enabl...

  13. Electron energy-loss spectroscopy of branched gap plasmon resonators

    DEFF Research Database (Denmark)

    Raza, Søren; Esfandyarpour, Majid; Koh, Ai Leen

    2016-01-01

    The miniaturization of integrated optical circuits below the diffraction limit for high-speed manipulation of information is one of the cornerstones in plasmonics research. By coupling to surface plasmons supported on nanostructured metallic surfaces, light can be confined to the nanoscale......, enabling the potential interface to electronic circuits. In particular, gap surface plasmons propagating in an air gap sandwiched between metal layers have shown extraordinary mode confinement with significant propagation length. In this work, we unveil the optical properties of gap surface plasmons...... in silver nanoslot structures with widths of only 25 nm. We fabricate linear, branched and cross-shaped nanoslot waveguide components, which all support resonances due to interference of counter-propagating gap plasmons. By exploiting the superior spatial resolution of a scanning transmission electron...

  14. Low-loss tunable all-in-fiber filter for Raman spectroscopy

    DEFF Research Database (Denmark)

    Brunetti, Anna Chiara; Scolari, Lara; Lund-Hansen, Toke

    2011-01-01

    We show a novel in-line Rayleigh-rejection filter for Raman spectroscopy, based on a solid-core Photonic Crystal Fiber (PCF) filled with a high-index material. The device is low-loss and thermally tunable, and allows for a strong attenuation of the Rayleigh line at 532nm and the transmission...... of the Raman lines in a broad wavenumber range....

  15. Energy loss and thermalization of low-energy electrons

    International Nuclear Information System (INIS)

    LaVerne, J.A.; Mozumder, A.; Notre Dame Univ., IN

    1984-01-01

    Various processes involved in the moderation of low-energy electrons (< 10 keV in energy) have been delineated in gaseous and liquid media. The discussion proceeds in two stages. The first stage ends and the second stage begins when the electron energy equals the first excitation potential of the medium. The second stage ends with thermalization. Cross sections for electronic excitation and for the excitation (and de-excitation) of sub-electronic processes have been evaluated and incorporated in suitable stopping power and transport theories. Comparison between experiment and theory and intercomparisons between theories and experiments have been provided where possible. (author)

  16. The impact of cell culture equipment on energy loss.

    Science.gov (United States)

    Davies, Lleucu B; Kiernan, Michael N; Bishop, Joanna C; Thornton, Catherine A; Morgan, Gareth

    2014-01-01

    Light energy of discrete wavelengths supplied via lasers and broadband intense pulsed light have been used therapeutically for many years. In vitro models complement clinical studies, especially for the elucidation of underlying mechanisms of action. Clarification that light energy reaches the cells is necessary when developing protocols for the treatment of cells using in vitro models. Few studies report on energy loss in cell culture equipment. The ability of energy from light with therapeutic potential to reach cells in culture needs to be determined; this includes determining the proportion of light energy lost within standard cell culture media and cell culture vessels. The energy absorption of cell culture media, with/without the pH indicator dye phenol red, and the loss of energy within different plastics and glassware used typically for in vitro cell culture were investigated using intense pulsed light and a yellow pulsed dye laser. Media containing phenol red have a distinctive absorption peak (560 nm) absent in phenol red-free media and restored by the addition of phenol red. For both light sources, energy loss was lowest in standard polystyrene tissue culture flasks or multi-well plates and highest in polypropylene vessels or glass tubes. The effects of phenol red-free media on the absorption of energy varied with the light source used. Phenol red-free media are the media of choice; polystyrene vessels with flat surfaces such as culture flasks or multi-well plates should be used in preference to polypropylene or glass vessels.

  17. Uncertainty, loss aversion, and markets for energy efficiency

    International Nuclear Information System (INIS)

    Greene, David L.

    2011-01-01

    Increasing energy efficiency is critical to mitigating greenhouse gas emissions from fossil-fuel combustion, reducing oil dependence, and achieving a sustainable global energy system. The tendency of markets to neglect apparently cost-effective energy efficiency options has been called the 'efficiency gap' or 'energy paradox.' The market for energy efficiency in new, energy-using durable goods, however, appears to have a bias that leads to undervaluation of future energy savings relative to their expected value. This paper argues that the bias is chiefly produced by the combination of substantial uncertainty about the net value of future fuel savings and the loss aversion of typical consumers. This framework relies on the theory of context-dependent preferences. The uncertainty-loss aversion bias against energy efficiency is quantifiable, making it potentially correctible by policy measures. The welfare economics of such policies remains unresolved. Data on the costs of increased fuel economy of new passenger cars, taken from a National Research Council study, illustrate how an apparently cost-effective increase in energy efficiency would be uninteresting to loss-averse consumers.

  18. Study of optical and electronic properties of nickel from reflection electron energy loss spectra

    Science.gov (United States)

    Xu, H.; Yang, L. H.; Da, B.; Tóth, J.; Tőkési, K.; Ding, Z. J.

    2017-09-01

    We use the classical Monte Carlo transport model of electrons moving near the surface and inside solids to reproduce the measured reflection electron energy-loss spectroscopy (REELS) spectra. With the combination of the classical transport model and the Markov chain Monte Carlo (MCMC) sampling of oscillator parameters the so-called reverse Monte Carlo (RMC) method was developed, and used to obtain optical constants of Ni in this work. A systematic study of the electronic and optical properties of Ni has been performed in an energy loss range of 0-200 eV from the measured REELS spectra at primary energies of 1000 eV, 2000 eV and 3000 eV. The reliability of our method was tested by comparing our results with the previous data. Moreover, the accuracy of our optical data has been confirmed by applying oscillator strength-sum rule and perfect-screening-sum rule.

  19. Energy dispersive X-ray spectroscopy with microcalorimeters

    International Nuclear Information System (INIS)

    Hollerith, C.; Wernicke, D.; Buehler, M.; Feilitzsch, F. von; Huber, M.; Hoehne, J.; Hertrich, T.; Jochum, J.; Phelan, K.; Stark, M.; Simmnacher, B.; Weiland, W.; Westphal, W.

    2004-01-01

    Shrinking feature sizes in semiconductor device production as well as the use of new materials demand innovation in device technology and material analysis. X-ray spectrometers based on superconducting sensor technology are currently closing the gap between fast energy dispersive spectroscopy (EDS) and high-resolution wavelength dispersive spectroscopy (WDS). This work reports on the successful integration of iridium/gold transition edge sensors in the first industrially used microcalorimeter EDS. The POLARIS microcalorimeter system is installed at the failure analysis lab FA5 at Infineon Technologies AG in Neuperlach (Munich) and is used in routine analysis

  20. Data Acquisition System for Electron Energy Loss Coincident Spectrometers

    International Nuclear Information System (INIS)

    Zhang Chi; Yu Xiaoqi; Yang Tao

    2005-01-01

    A Data Acquisition System (DAQ) for electron energy loss coincident spectrometers (EELCS) has been developed. The system is composed of a Multiplex Time-Digital Converter (TDC) that measures the flying time of positive and negative ions and a one-dimension position-sensitive detector that records the energy loss of scattering electrons. The experimental data are buffered in a first-in-first-out (FIFO) memory module, then transferred from the FIFO memory to PC by the USB interface. The DAQ system can record the flying time of several ions in one collision, and allows of different data collection modes. The system has been demonstrated at the Electron Energy Loss Coincident Spectrometers at the Laboratory of Atomic and Molecular Physics, USTC. A detail description of the whole system is given and experimental results shown

  1. Simulation of electron energy loss spectra of nanomaterials with linear-scaling density functional theory

    International Nuclear Information System (INIS)

    Tait, E W; Payne, M C; Ratcliff, L E; Haynes, P D; Hine, N D M

    2016-01-01

    Experimental techniques for electron energy loss spectroscopy (EELS) combine high energy resolution with high spatial resolution. They are therefore powerful tools for investigating the local electronic structure of complex systems such as nanostructures, interfaces and even individual defects. Interpretation of experimental electron energy loss spectra is often challenging and can require theoretical modelling of candidate structures, which themselves may be large and complex, beyond the capabilities of traditional cubic-scaling density functional theory. In this work, we present functionality to compute electron energy loss spectra within the onetep linear-scaling density functional theory code. We first demonstrate that simulated spectra agree with those computed using conventional plane wave pseudopotential methods to a high degree of precision. The ability of onetep to tackle large problems is then exploited to investigate convergence of spectra with respect to supercell size. Finally, we apply the novel functionality to a study of the electron energy loss spectra of defects on the (1 0 1) surface of an anatase slab and determine concentrations of defects which might be experimentally detectable. (paper)

  2. Daily pattern of energy distribution and weight loss.

    Science.gov (United States)

    Raynor, Hollie A; Li, Fan; Cardoso, Chelsi

    2018-08-01

    Timing of energy intake, a temporal dietary pattern, may enhance health. Eating a greater amount of energy earlier and a smaller amount of energy later in the day, a behavioral circadian rhythm, may assist with chronoenhancement. Chronoenhancement seeks to enhance entrainment (synchronization) of biological and behavioral circadian rhythms. In humans, research reports that eating a greater amount of energy early and a smaller amount of energy later in the day increases dietary induced thermogenesis, improves cardiometabolic outcomes, and enhances weight loss. However, little human research has examined if this eating pattern enhances regularity of biological circadian rhythm. In a randomized controlled 8-week pilot study, the influence of energy distribution timing on weight loss and regularity of sleep onset and wake times (marker for biological circadian rhythm) was examined. Within an hypocaloric, three-meal prescription, participants (n = 8) were assigned to either: 1) Morning: 50%, 30%, and 20% of kcal at breakfast, lunch, and dinner, respectively; or 2) Evening: 20%, 30%, and 50% of kcal at breakfast, lunch, and dinner, respectively. Percent weight loss and regularity of sleep onset and wake times were significantly (p energy distribution timing on health, longer studies conducted in free-living participants, with dietary intake assessed using time-stamped methods, that include measures of the circadian timing system are needed. This small review is based upon a symposium presentation at the Society of the Study of Ingestive Behavior in 2017. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Josephson spectroscopy of terahertz losses in [100]-tilt YBa2Cu3O7-x bicrystal junctions

    International Nuclear Information System (INIS)

    Divin, Y; Lyatti, M

    2008-01-01

    Terahertz losses in the [100]-tilt YBa 2 Cu 3 O 7-x grain-boundary junctions were studied using admittance Josephson spectroscopy. The I-Vcurves of the [100]-tilt YBa 2 Cu 3 O 7-x junctions, when annealed in atomic oxygen, were described by the resistively shunted junction model (RSJ) with an accuracy of better than 0.5% at the temperature range, where the characteristic voltage I c R n n -1 . At low temperatures, where I c R n >> kT/2e, the absorption of Josephson radiation by optical phonon modes in YBa 2 Cu 3 O 7-x was found to be reflected in the I-V curve of the [100]-tilt junctions. The most prominent structure is situated at the voltages V ∼ 9.5 mV, which gives the corresponding Josephson frequency of 4.6 THz in good agreement with the frequency of the strongest IR active optical phonon mode in YBa 2 Cu 3 O 7-x . Assignment of additional lines in the derived losses is discussed according to available data on lattice dynamic calculations and experimental data for a dynamic conduction Reσ 1 (f) of YBa 2 Cu 3 O 7-x . Josephson spectroscopy might be useful for study of low-energy excitations in high-T c materials

  4. Beam energy loss to parasitic modes in SPEAR II

    International Nuclear Information System (INIS)

    Allen, M.A.; Paterson, J.M.; Rees, J.R.; Wilson, P.B.

    1975-01-01

    The energy loss due to the excitation of parasitic modes in the SPEAR II rf cavities and vacuum chamber components was measured by observing the shift in synchronous phase angle as a function of circulating beam current and accelerating cavity voltage. The resulting parasitic mode loss resistance is 5 M OMEGA at a bunch length of 6.5 cm. The loss resistance varies with bunch length sigma/sub z/ approximately as exp(-0.3 sigma/sub z/). If the measured result is compared with reasonable theoretical predictions, it may be inferred that the major portion of the parasitic loss takes place in ring vacuum components rather than in the rf cavities. (auth)

  5. Energy Drinks, Weight Loss, and Disordered Eating Behaviors

    Science.gov (United States)

    Jeffers, Amy J.; Vatalaro Hill, Katherine E.; Benotsch, Eric G.

    2014-01-01

    Objective: The present study examined energy drink consumption and relations with weight loss attempts and behaviors, body image, and eating disorders. Participants/Methods: This is a secondary analysis using data from 856 undergraduate students who completed the American College Health Association-National College Health Assessment II…

  6. Acceleration and energy loss in N = 4 SYM

    International Nuclear Information System (INIS)

    Chernicoff, Mariano; Gueijosa, Alberto

    2009-01-01

    This contribution is based on two talks given at the XIII Mexican School of Particles and Fields. We revisit some of the results presented in [19], concerning the rate of energy loss of an accelerating quark in strongly-coupled N = 4 super-Yang-Mills.

  7. Acceleration and energy loss in N = 4 SYM

    Science.gov (United States)

    Chernicoff, Mariano; Güijosa, Alberto

    2009-04-01

    This contribution is based on two talks given at the XIII Mexican School of Particles and Fields. We revisit some of the results presented in [19], concerning the rate of energy loss of an accelerating quark in strongly-coupled N = 4 super-Yang-Mills.

  8. Rotating gravity currents. Part 1. Energy loss theory

    Science.gov (United States)

    Martin, J. R.; Lane-Serff, G. F.

    2005-01-01

    A comprehensive energy loss theory for gravity currents in rotating rectangular channels is presented. The model is an extension of the non-rotating energy loss theory of Benjamin (J. Fluid Mech. vol. 31, 1968, p. 209) and the steady-state dissipationless theory of rotating gravity currents of Hacker (PhD thesis, 1996). The theory assumes the fluid is inviscid, there is no shear within the current, and the Boussinesq approximation is made. Dissipation is introduced using a simple method. A head loss term is introduced into the Bernoulli equation and it is assumed that the energy loss is uniform across the stream. Conservation of momentum, volume flux and potential vorticity between upstream and downstream locations is then considered. By allowing for energy dissipation, results are obtained for channels of arbitrary depth and width (relative to the current). The results match those from earlier workers in the two limits of (i) zero rotation (but including dissipation) and (ii) zero dissipation (but including rotation). Three types of flow are identified as the effect of rotation increases, characterized in terms of the location of the outcropping interface between the gravity current and the ambient fluid on the channel boundaries. The parameters for transitions between these cases are quantified, as is the detailed behaviour of the flow in all cases. In particular, the speed of the current can be predicted for any given channel depth and width. As the channel depth increases, the predicted Froude number tends to surd 2, as for non-rotating flows.

  9. Energy loss of muons in the energy range 1-10000 GeV

    International Nuclear Information System (INIS)

    Lohmann, W.; Kopp, R.; Voss, R.

    1985-01-01

    A summary is given of the most recent formulae for the cross-sections contributing to the energy loss of muons in matter, notably due to electro-magnetic interactions (ionization, bremsstrahlung and electron-pair production) and nuclear interactions. Computed energy losses dE/dx are tabulated for muons with energy between 1 GeV and 10,000 GeV in a number of materials commonly used in high-energy physics experiments. In comparison with earlier tables, these show deviations that grow with energy and amount to several per cent at 200 GeV muon energy. (orig.)

  10. Control of phase transition dynamics in media with nanoscale nonuniformities by coherence loss spectroscopy

    International Nuclear Information System (INIS)

    Brodsky, Anatol M

    2010-01-01

    The optical nondestructive characterization of chemical transformation dynamics and diffusion kinetics, including phase transitions, in heterogeneous media with a random distribution of nanoparticles (nano-nonuniformities), is of great theoretical and practical importance. Such characterization, with the help of coherence loss spectroscopy, considered in this paper can be applied for the control of a number of industrial processes dynamics, environmental monitoring, and medical diagnostics and therapy. As a specific example, the growth of crystal nuclei (embrions) as a result of the diffusion to them of a substance from the surrounding supersaturated solution is considered

  11. Energy loss to parasitic modes of accelerating cavities

    International Nuclear Information System (INIS)

    Sands, M.

    1974-01-01

    At the maximum stored current, each circulating beam in PEP will consist of three bunches, each about 10 cm long containing 1.5 /times/ 10 12 particles. The large electric charge carried by such a bunch (2.5 /times/ 10/sup /minus/7/ coulomb) will, because of its short length, give rise to a large transient excitation of hundreds of parasitic modes in the accelerating cavities. The energy loss of the stored beam to the cavities from this process may be comparable to the loss to synchrotron radiation, and may, therefore, require a significant increase in power from the accelerating rf system. In this note I considered three aspects of this effect. First, an attempt is made to estimate the magnitude of the energy loss of a bunch in a single passage through the accelerating cavities. Then, I consider the effects of the periodic passages of the bunches in a single stored beam. And finally, I look at the consequences of storing two counter-rotating beams. The general conclusions are that the magnitude energy loss to the parasitic modes is serious, though probably not disastrous; and that, in general, the separate stored bunches will act incoherently. 2 refs., 7 figs

  12. Photoelectron Energy Loss in Al(002) Revisited: Retrieval of the Single Plasmon Loss Energy Distribution by a Fourier Transform Method

    Science.gov (United States)

    Santana, Victor Mancir da Silva; David, Denis; de Almeida, Jailton Souza; Godet, Christian

    2018-06-01

    A Fourier transform (FT) algorithm is proposed to retrieve the energy loss function (ELF) of solid surfaces from experimental X-ray photoelectron spectra. The intensity measured over a broad energy range towards lower kinetic energies results from convolution of four spectral distributions: photoemission line shape, multiple plasmon loss probability, X-ray source line structure and Gaussian broadening of the photoelectron analyzer. The FT of the measured XPS spectrum, including the zero-loss peak and all inelastic scattering mechanisms, being a mathematical function of the respective FT of X-ray source, photoemission line shape, multiple plasmon loss function, and Gaussian broadening of the photoelectron analyzer, the proposed algorithm gives straightforward access to the bulk ELF and effective dielectric function of the solid, assuming identical ELF for intrinsic and extrinsic plasmon excitations. This method is applied to aluminum single crystal Al(002) where the photoemission line shape has been computed accurately beyond the Doniach-Sunjic approximation using the Mahan-Wertheim-Citrin approach which takes into account the density of states near the Fermi level; the only adjustable parameters are the singularity index and the broadening energy D (inverse hole lifetime). After correction for surface plasmon excitations, the q-averaged bulk loss function, q , of Al(002) differs from the optical value Im[- 1 / ɛ( E, q = 0)] and is well described by the Lindhard-Mermin dispersion relation. A quality criterion of the inversion algorithm is given by the capability of observing weak interband transitions close to the zero-loss peak, namely at 0.65 and 1.65 eV in ɛ( E, q) as found in optical spectra and ab initio calculations of aluminum.

  13. Photoelectron Energy Loss in Al(002) Revisited: Retrieval of the Single Plasmon Loss Energy Distribution by a Fourier Transform Method

    Science.gov (United States)

    Santana, Victor Mancir da Silva; David, Denis; de Almeida, Jailton Souza; Godet, Christian

    2018-04-01

    A Fourier transform (FT) algorithm is proposed to retrieve the energy loss function (ELF) of solid surfaces from experimental X-ray photoelectron spectra. The intensity measured over a broad energy range towards lower kinetic energies results from convolution of four spectral distributions: photoemission line shape, multiple plasmon loss probability, X-ray source line structure and Gaussian broadening of the photoelectron analyzer. The FT of the measured XPS spectrum, including the zero-loss peak and all inelastic scattering mechanisms, being a mathematical function of the respective FT of X-ray source, photoemission line shape, multiple plasmon loss function, and Gaussian broadening of the photoelectron analyzer, the proposed algorithm gives straightforward access to the bulk ELF and effective dielectric function of the solid, assuming identical ELF for intrinsic and extrinsic plasmon excitations. This method is applied to aluminum single crystal Al(002) where the photoemission line shape has been computed accurately beyond the Doniach-Sunjic approximation using the Mahan-Wertheim-Citrin approach which takes into account the density of states near the Fermi level; the only adjustable parameters are the singularity index and the broadening energy D (inverse hole lifetime). After correction for surface plasmon excitations, the q-averaged bulk loss function, q , of Al(002) differs from the optical value Im[- 1 / ɛ(E, q = 0)] and is well described by the Lindhard-Mermin dispersion relation. A quality criterion of the inversion algorithm is given by the capability of observing weak interband transitions close to the zero-loss peak, namely at 0.65 and 1.65 eV in ɛ(E, q) as found in optical spectra and ab initio calculations of aluminum.

  14. Mode-dependent dispersion in Raman line shapes: Observation and implications from ultrafast Raman loss spectroscopy

    International Nuclear Information System (INIS)

    Umapathy, S.; Mallick, B.; Lakshmanna, A.

    2010-01-01

    Ultrafast Raman loss spectroscopy (URLS) enables one to obtain the vibrational structural information of molecular systems including fluorescent materials. URLS, a nonlinear process analog to stimulated Raman gain, involves a narrow bandwidth picosecond Raman pump pulse and a femtosecond broadband white light continuum. Under nonresonant condition, the Raman response appears as a negative (loss) signal, whereas, on resonance with the electronic transition the line shape changes from a negative to a positive through a dispersive form. The intensities observed and thus, the Franck-Condon activity (coordinate dependent), are sensitive to the wavelength of the white light corresponding to a particular Raman frequency with respect to the Raman pump pulse wavelength, i.e., there is a mode-dependent response in URLS.

  15. Derivation of Hamaker Dispersion Energy of Amorphous Carbon Surfaces in Contact with Liquids Using Photoelectron Energy-Loss Spectra

    Science.gov (United States)

    Godet, Christian; David, Denis

    2017-12-01

    Hamaker interaction energies and cutoff distances have been calculated for disordered carbon films, in contact with purely dispersive (diiodomethane) or polar (water) liquids, using their experimental dielectric functions ɛ ( q, ω) obtained over a broad energy range. In contrast with previous works, a q-averaged q is derived from photoelectron energy-loss spectroscopy (XPS-PEELS) where the energy loss function (ELF) q is a weighted average over allowed transferred wave vector values, q, given by the physics of bulk plasmon excitation. For microcrystalline diamond and amorphous carbon films with a wide range of (sp3/sp2 + sp3) hybridization, non-retarded Hamaker energies, A 132 ( L < 1 nm), were calculated in several configurations, and distance and wavenumber cutoff values were then calculated based on A 132 and the dispersive work of adhesion obtained from contact angles. A geometric average approximation, H 0 CVL = ( H 0 CVC H 0 LVL )1/2, holds for the cutoff separation distances obtained for carbon-vacuum-liquid (CVL), carbon-vacuum-carbon (CVC) and liquid-vacuum-liquid (LVL) equilibrium configurations. The linear dependence found for A CVL, A CLC and A CLV values as a function of A CVC, for each liquid, allows predictive relationships for Hamaker energies (in any configuration) using experimental determination of the dispersive component of the surface tension, {γ}_{CV}^d , and a guess value of the cutoff distance H 0 CVC of the solid. [Figure not available: see fulltext.

  16. Neutrino energy loss rate in a stellar plasma

    International Nuclear Information System (INIS)

    Esposito, S.; Mangano, G.; Miele, G.; Picardi, I.; Pisanti, O.

    2003-01-01

    We review the purely leptonic neutrino emission processes, contributing to the energy loss rate of the stellar plasma. We perform a complete analysis up to the first order in the electromagnetic coupling constant. In particular the radiative electromagnetic corrections, at order α, to the process e + e - →νν-bar at finite density and temperature have been computed. This process gives one of the main contributions to the cooling of stellar interior in the late stages of star evolution. As a result of the analysis we find that the corrections affect the energy loss rate, computed at tree level, by a factor (-4-1)% in the temperature and density region where the pair annihilation is the most efficient cooling mechanism

  17. Limiting energy loss distributions for multiphoton channeling radiation

    International Nuclear Information System (INIS)

    Bondarenco, M.V.

    2015-01-01

    Recent results in the theory of multiphoton spectra for coherent radiation sources are overviewed, with the emphasis on channeling radiation. For the latter case, the importance of the order of resummation and averaging is emphasized. Limiting shapes of multiphoton spectra at high intensity are discussed for different channeling regimes. In some spectral regions, there emerges a correspondence between the radiative energy loss and the electron integrals of motion

  18. Probing hot dense matter with jet energy loss

    International Nuclear Information System (INIS)

    Levai, P.; Barnafoeldi, G.G.; Gyulassy, M.; Vitev, I.; Fai, G.; Zhang, Y.

    2002-01-01

    We study, in a pQCD calculation augmented by nuclear effects, the jet energy loss needed to reproduce the π 0 spectra in Au+Au collisions at large p T , measured by PHENIX at RHIC. The transverse width of the parton momentum distributions (intrinsic k T ) is used phenomenologically to obtain a reliable baseline pp result. Jet quenching is applied to the nuclear spectra (including shadowing and multiscattering) to fit the data. Latest results on fluctuating gluon radiation are considered to measure the opacity of the produced hot dense matter at RHIC energy. (orig.)

  19. Development of decay energy spectroscopy using low temperature detectors.

    Science.gov (United States)

    Jang, Y S; Kim, G B; Kim, K J; Kim, M S; Lee, H J; Lee, J S; Lee, K B; Lee, M K; Lee, S J; Ri, H C; Yoon, W S; Yuryev, Y N; Kim, Y H

    2012-09-01

    We have developed a high-resolution detection technique for measuring the energy and activity of alpha decay events using low-temperature detectors. A small amount of source material containing alpha-emitting radionuclides was enclosed in a 4π metal absorber. The energy of the alpha particles as well as that of the recoiled nuclides, low-energy electrons, and low-energy x-rays and γ-rays was converted into thermal energy of the gold absorber. A metallic magnetic calorimeter serving as a fast and sensitive thermometer was thermally attached to the metal absorber. In the present report, experimental demonstrations of Q spectroscopy were made with a new meander-type magnetic calorimeter. The thermal connection between the temperature sensor and the absorber was established with annealed gold wires. Each alpha decay event in the absorber resulted in a temperature increase of the absorber and the temperature sensor. Using the spectrum measured for a drop of (226)Ra solution in a 4π gold absorber, all of the alpha emitters in the sample were identified with a demonstration of good detector linearity. The resolution of the (226)Ra spectrum showed a 3.3 keV FWHM at its Q value together with an expected gamma escape peak at the energy shifted by its γ-ray energy. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Power Loss Analysis and Comparison of Segmented and Unsegmented Energy Coupling Coils for Wireless Energy Transfer.

    Science.gov (United States)

    Tang, Sai Chun; McDannold, Nathan J

    2015-03-01

    This paper investigated the power losses of unsegmented and segmented energy coupling coils for wireless energy transfer. Four 30-cm energy coupling coils with different winding separations, conductor cross-sectional areas, and number of turns were developed. The four coils were tested in both unsegmented and segmented configurations. The winding conduction and intrawinding dielectric losses of the coils were evaluated individually based on a well-established lumped circuit model. We found that the intrawinding dielectric loss can be as much as seven times higher than the winding conduction loss at 6.78 MHz when the unsegmented coil is tightly wound. The dielectric loss of an unsegmented coil can be reduced by increasing the winding separation or reducing the number of turns, but the power transfer capability is reduced because of the reduced magnetomotive force. Coil segmentation using resonant capacitors has recently been proposed to significantly reduce the operating voltage of a coil to a safe level in wireless energy transfer for medical implants. Here, we found that it can naturally eliminate the dielectric loss. The coil segmentation method and the power loss analysis used in this paper could be applied to the transmitting, receiving, and resonant coils in two- and four-coil energy transfer systems.

  1. Inelastic collisions of medium energy atomic elements. Qualitative model of energy losses during collisions

    International Nuclear Information System (INIS)

    Pustovit, A.N.

    2006-01-01

    A new approach to the theoretical description of energy losses of atomic particle of medium energy during their interaction with the substance is proposed. The corner-stone of this approach is the supposition that all of the collision processes have inelastic nature during particle movement through the substance, while the calculation of the atomic particles braking is based on the law of their dispersion and the laws of energy and momentum conservation at the inelastic collisions. It is shown that inelastic atomic collision there are three dispersion zones for the only potential interaction with different laws, which characterize energy losses. The application conditions of this approach are determined [ru

  2. Beam Loss Calibration Studies for High Energy Proton Accelerators

    CERN Document Server

    Stockner, M

    2007-01-01

    CERN's Large Hadron Collider (LHC) is a proton collider with injection energy of 450 GeV and collision energy of 7 TeV. Superconducting magnets keep the particles circulating in two counter rotating beams, which cross each other at the Interaction Points (IP). Those complex magnets have been designed to contain both beams in one yoke within a cryostat. An unprecedented amount of energy will be stored in the circulating beams and in the magnet system. The LHC outperforms other existing accelerators in its maximum beam energy by a factor of 7 and in its beam intensity by a factor of 23. Even a loss of a small fraction of the beam particles may cause the transition from the superconducting to the normal conducting state of the coil or cause physical damage to machine components. The unique combination of these extreme beam parameters and the highly advanced superconducting technology has the consequence that the LHC needs a more efficient beam cleaning and beam loss measurement system than previous accelerators....

  3. Characteristic losses of electrons energy under reflection from leadsilicate glasses

    International Nuclear Information System (INIS)

    Gusarov, A.I.; Mashkov, V.A.; Pronin, V.P.; Tyutikov, A.M.

    1986-01-01

    The spectra of characteristic losses of energy (CLE) for the case of electron reflection from the surface of leadsilicate glasses of the composition xPbOx(1-x)SiO 2 , depending on molar concentration of lead oxide x, has been calculated for the first time. It is shown that the given model of glass energy structure permits to describe correctly general behaviour of CLE spectrum. However, the energy of plasma maximum measured experimentally remains approximately constant. The behaviour can be conditioned by ω 0 dependence on x[4], which has not been taken into account, and (or) by a slower change in ΔE, than it has been assumed. Further refining of theory and experiment is required to solve the problem

  4. High Q diamond hemispherical resonators: fabrication and energy loss mechanisms

    International Nuclear Information System (INIS)

    Bernstein, Jonathan J; Bancu, Mirela G; Bauer, Joseph M; Cook, Eugene H; Kumar, Parshant; Nyinjee, Tenzin; Perlin, Gayatri E; Ricker, Joseph A; Teynor, William A; Weinberg, Marc S; Newton, Eric

    2015-01-01

    We have fabricated polycrystalline diamond hemispheres by hot-filament CVD (HFCVD) in spherical cavities wet-etched into a high temperature glass substrate CTE matched to silicon. Hemispherical resonators 1.4 mm in diameter have a Q of up to 143 000 in the fundamental wineglass mode, for a ringdown time of 2.4 s. Without trimming, resonators have the two degenerate wineglass modes frequency matched as close as 2 Hz, or 0.013% of the resonant frequency (∼16 kHz). Laser trimming was used to match resonant modes on hemispheres to 0.3 Hz. Experimental and FEA energy loss studies on cantilevers and hemispheres examine various energy loss mechanisms, showing that surface related losses are dominant. Diamond cantilevers with a Q of 400 000 and a ringdown time of 15.4 s were measured, showing the potential of polycrystalline diamond films for high Q resonators. These resonators show great promise for use as hemispherical resonant gyroscopes (HRGs) on a chip. (paper)

  5. Elastic energy loss and longitudinal straggling of a hard jet

    International Nuclear Information System (INIS)

    Majumder, A.

    2009-01-01

    The elastic energy loss encountered by jets produced in deep-inelastic scattering (DIS) off a large nucleus is studied in the collinear limit. In close analogy to the case of (nonradiative) transverse momentum broadening, which is dependent on the medium transport coefficient q, a class of medium enhanced higher twist operators which contribute to the nonradiative loss of the forward light-cone momentum of the jet (q - ) are identified and the leading correction in the limit of asymptotically high q - is isolated. Based on these operator products, a new transport coefficient e is motivated which quantifies the energy loss per unit length encountered by the hard jet. These operator products are then computed, explicitly, in the case of a similar hard jet traversing a deconfined quark-gluon plasma (QGP) in the hard-thermal-loop (HTL) approximation. This is followed by an evaluation of subleading contributions which are suppressed by the inverse light-cone momentum q - , which yields the longitudinal 'straggling', i.e., a slight change in light cone momentum due to the Brownian propagation through a medium with a fluctuating color field.

  6. Gravity resonance spectroscopy constrains dark energy and dark matter scenarios.

    Science.gov (United States)

    Jenke, T; Cronenberg, G; Burgdörfer, J; Chizhova, L A; Geltenbort, P; Ivanov, A N; Lauer, T; Lins, T; Rotter, S; Saul, H; Schmidt, U; Abele, H

    2014-04-18

    We report on precision resonance spectroscopy measurements of quantum states of ultracold neutrons confined above the surface of a horizontal mirror by the gravity potential of Earth. Resonant transitions between several of the lowest quantum states are observed for the first time. These measurements demonstrate that Newton's inverse square law of gravity is understood at micron distances on an energy scale of 10-14  eV. At this level of precision, we are able to provide constraints on any possible gravitylike interaction. In particular, a dark energy chameleon field is excluded for values of the coupling constant β>5.8×108 at 95% confidence level (C.L.), and an attractive (repulsive) dark matter axionlike spin-mass coupling is excluded for the coupling strength gsgp>3.7×10-16 (5.3×10-16) at a Yukawa length of λ=20  μm (95% C.L.).

  7. Technology Roadmap. Energy Loss Reduction and Recovery in Industrial Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2004-11-01

    To help guide R&D decision-making and gain industry insights on the top opportunities for improved energy systems, ITP sponsored the Energy Loss Reduction and Recoveryin Energy Systems Roadmapping Workshopin April 2004 in Baltimore, Maryland. This Technology Roadmapis based largely on the results of the workshop and additional industrial energy studies supported by ITP and EERE. It summarizes industry feedback on the top opportunities for R&D investments in energy systems, and the potential for national impacts on energy use and the environment.

  8. Angular distribution of scattered electron and medium energy electron spectroscopy for metals

    International Nuclear Information System (INIS)

    Oguri, Takeo; Ishioka, Hisamichi; Fukuda, Hisashi; Irako, Mitsuhiro

    1986-01-01

    The angular distribution (AD) of scattered electrons produced by medium energy incident electrons (E P = 50 ∼ 300 eV) from polycrystalline Ti, Fe, Ni, Cu and Au were obtained by the angle-resolved medium energy electron spectrometer. The AD of the energy loss peaks are similar figures to AD of the elastically reflected electron peaks. Therefore, the exchanged electrons produced by the knock-on collision between the incident electrons and those of metals without momentum transfer are observed as the energy loss spectra (ELS). This interpretation differs from the inconsequent interpretation by the dielectric theory or the interband transition. The information depth and penetration length are obtained from AD of the Auger electron peaks. The contribution of the surface to spectra is 3 % at the maximum for E P = 50 eV. The true secondary peaks representing the secondary electron emission spectroscopy (SES) are caused by the emissions of the energetic electrons (kT e ≥ 4 eV), and SES is the inversion of ELS. The established fundamental view is that the medium energy electron spectra represent the total bulk density of states. (author)

  9. An overview of heavy quark energy loss puzzle at RHIC

    International Nuclear Information System (INIS)

    Djordjevic, Magdalena

    2006-01-01

    We give a theoretical overview of the heavy quark tomography puzzle posed by recent non-photonic single electron data from central Au+Au collisions at √s = 200A GeV. We show that radiative energy loss mechanisms alone are not able to explain large single electron suppression data, as long as realistic parameter values are assumed. We argue that a combined collisional and radiative pQCD approach can solve a substantial part of the non-photonic single electron puzzle

  10. Acceleration and Energy Loss in N=4 SYM

    OpenAIRE

    Chernicoff, Mariano; Guijosa, Alberto

    2009-01-01

    We give a brief overview of the results obtained in arXiv:0803.3070, concerning the rate of energy loss of an accelerating quark in strongly-coupled N=4 super-Yang-Mills, both at zero and finite temperature. For phenomenological purposes, our main result is that, when a quark is created within the plasma together with its corresponding antiquark, the quark starts feeling the plasma only after the q-\\bar{q} separation becomes larger than the (v-dependent) screening length, and from this point ...

  11. EELOSS: the program for calculation of electron energy loss data

    International Nuclear Information System (INIS)

    Tanaka, Shun-ichi

    1980-10-01

    A computer code EELOSS has been developed to obtain the electron energy loss data required for shielding and dosimetry of beta- and gamma-rays in nuclear plants. With this code, the following data are obtainable for any energy from 0.01 to 15 MeV in any medium (metal, insulator, gas, compound, or mixture) composed of any choice of 69 elements with atomic number 1 -- 94: a) Collision stopping power, b) Restricted collision stopping power, c) Radiative stopping power, and d) Bremsstrahlung production cross section. The availability of bremsstrahlung production cross section data obtained by the EELOSS code is demonstrated by the comparison of calculated gamma-ray spectrum with measured one in Pb layer, where electron-photon cascade is included implicitly. As a result, it is concluded that the uncertainty in the bremsstrahlung production cross sections is negligible in the practical shielding calculations of gamma rays of energy less than 15 MeV, since the bremsstrahlung production cross sections increase with the gamma-ray energy and the uncertainty for them decreases with increasing the gamma-ray energy. Furthermore, the accuracy of output data of the EELOSS code is evaluated in comparison with experimental data, and satisfactory agreements are observed concerning the stopping power. (J.P.N.)

  12. The role of energy losses in photosynthetic light harvesting

    Science.gov (United States)

    Krüger, T. P. J.; van Grondelle, R.

    2017-07-01

    Photosynthesis operates at the bottom of the food chain to convert the energy of light into carbohydrates at a remarkable global rate of about 130 TW. Nonetheless, the overall photosynthetic process has a conversion efficiency of a few percent at best, significantly less than bottom-up photovoltaic cells. The primary photosynthetic steps, consisting of light harvesting and charge separation, are often presented as having near-unity quantum efficiency but this holds only true under ideal conditions. In this review, we discuss the importance of energy loss mechanisms to establish robustness in photosynthetic light harvesting. Thermal energy dissipation of light-harvesting complexes (LHCs) in different environments is investigated and the relationships and contrasts between concentration quenching of high pigment concentrations, photoprotection (non-photochemical quenching), quenching due to protein aggregation, and fluorescence blinking are discussed. The role of charge-transfer states in light harvesting and energy dissipation is highlighted and the importance of controlled protein structural disorder to switch the light-harvesting antennae between effective light harvesters and efficient energy quenchers is underscored. The main LHC of plants, LHCII, is used as a prime example.

  13. The role of energy losses in photosynthetic light harvesting

    International Nuclear Information System (INIS)

    Krüger, T P J; Van Grondelle, R

    2017-01-01

    Photosynthesis operates at the bottom of the food chain to convert the energy of light into carbohydrates at a remarkable global rate of about 130 TW. Nonetheless, the overall photosynthetic process has a conversion efficiency of a few percent at best, significantly less than bottom-up photovoltaic cells. The primary photosynthetic steps, consisting of light harvesting and charge separation, are often presented as having near-unity quantum efficiency but this holds only true under ideal conditions. In this review, we discuss the importance of energy loss mechanisms to establish robustness in photosynthetic light harvesting. Thermal energy dissipation of light-harvesting complexes (LHCs) in different environments is investigated and the relationships and contrasts between concentration quenching of high pigment concentrations, photoprotection (non-photochemical quenching), quenching due to protein aggregation, and fluorescence blinking are discussed. The role of charge-transfer states in light harvesting and energy dissipation is highlighted and the importance of controlled protein structural disorder to switch the light-harvesting antennae between effective light harvesters and efficient energy quenchers is underscored. The main LHC of plants, LHCII, is used as a prime example. (topical review)

  14. Energy loss effect in high energy nuclear Drell-Yan process

    International Nuclear Information System (INIS)

    Duan, C.G.; Song, L.H.; Huo, L.J.; Li, G.L.

    2003-01-01

    The energy loss effect in nuclear matter, which is a nuclear effect apart from the nuclear effect on the parton distribution as in deep-inelastic scattering process, can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of the nuclear parton distribution studied only with lepton deep-inelastic scattering experimental data, the measured Drell-Yan production cross sections for 800 GeV proton incident on a variety of nuclear targets are analyzed within the Glauber framework which takes into account the energy loss of the beam proton. It is shown that the theoretical results with considering the energy loss effect are in good agreement with the FNAL E866 data. (orig.)

  15. Loss of Energy Concentration in Nonlinear Evolution Beam Equations

    Science.gov (United States)

    Garrione, Maurizio; Gazzola, Filippo

    2017-12-01

    Motivated by the oscillations that were seen at the Tacoma Narrows Bridge, we introduce the notion of solutions with a prevailing mode for the nonlinear evolution beam equation u_{tt} + u_{xxxx} + f(u)= g(x, t) in bounded space-time intervals. We give a new definition of instability for these particular solutions, based on the loss of energy concentration on their prevailing mode. We distinguish between two different forms of energy transfer, one physiological (unavoidable and depending on the nonlinearity) and one due to the insurgence of instability. We then prove a theoretical result allowing to reduce the study of this kind of infinite-dimensional stability to that of a finite-dimensional approximation. With this background, we study the occurrence of instability for three different kinds of nonlinearities f and for some forcing terms g, highlighting some of their structural properties and performing some numerical simulations.

  16. Medical radiation dosimetry theory of charged particle collision energy loss

    CERN Document Server

    McParland, Brian J

    2014-01-01

    Accurate radiation dosimetry is a requirement of radiation oncology, diagnostic radiology and nuclear medicine. It is necessary so as to satisfy the needs of patient safety, therapeutic and diagnostic optimisation, and retrospective epidemiological studies of the biological effects resulting from low absorbed doses of ionising radiation. The radiation absorbed dose received by the patient is the ultimate consequence of the transfer of kinetic energy through collisions between energetic charged particles and atoms of the tissue being traversed. Thus, the ability of the medical physicist to both measure and calculate accurately patient dosimetry demands a deep understanding of the physics of charged particle interactions with matter. Interestingly, the physics of charged particle energy loss has an almost exclusively theoretical basis, thus necessitating an advanced theoretical understanding of the subject in order to apply it appropriately to the clinical regime. ​ Each year, about one-third of the worl...

  17. Nonequilibrium electron energy-loss kinetics in metal clusters

    CERN Document Server

    Guillon, C; Fatti, N D; Vallee, F

    2003-01-01

    Ultrafast energy exchanges of a non-Fermi electron gas with the lattice are investigated in silver clusters with sizes ranging from 4 to 26 nm using a femtosecond pump-probe technique. The results yield evidence for a cluster-size-dependent slowing down of the short-time energy losses of the electron gas when it is strongly athermal. A constant rate is eventually reached after a few hundred femtoseconds, consistent with the electron gas internal thermalization kinetics, this behaviour reflecting evolution from an individual to a collective electron-lattice type of coupling. The timescale of this transient regime is reduced in small nanoparticles, in agreement with speeding up of the electron-electron interactions with size reduction. The experimental results are in quantitative agreement with numerical simulations of the electron kinetics.

  18. Impedance spectroscopy of PZT ceramics--measuring diffusion coefficients, mixed conduction, and Pb loss.

    Science.gov (United States)

    Donnelly, Niall J; Randall, Clive A

    2012-09-01

    Sintering of lead zirconate titanate (PZT) at high temperatures results in loss of Pb unless an ambient Pb activity is maintained. The tell-tale sign of Pb loss is an increased conductivity, usually manifested in unacceptably high values of tanδ. The conductivity is caused by oxygen vacancies and/or electron holes which are a byproduct of Pb evaporation. In the first part of this paper, it is shown how impedance spectroscopy can be used to separate ionic and electronic conductivity in a properly designed sample by selection of appropriate boundary conditions. Subsequently, impedance is used to probe defect concentrations in PZT during prolonged annealing at 700°C. It is found that oxygen vacancies are generated during annealing in air but the rate of generation actually decreases upon lowering the ambient pO(2). These results are explained by a model of Pb evaporation which, in this case, leads predominantly to oxygen vacancy generation. In principle, this effect could be used to generate a specific vacancy concentration in similar Pb-based oxides.

  19. Nonequilibrium thermodynamics and energy efficiency in weight loss diets

    Directory of Open Access Journals (Sweden)

    Fine Eugene J

    2007-07-01

    Full Text Available Abstract Carbohydrate restriction as a strategy for control of obesity is based on two effects: a behavioral effect, spontaneous reduction in caloric intake and a metabolic effect, an apparent reduction in energy efficiency, greater weight loss per calorie consumed. Variable energy efficiency is established in many contexts (hormonal imbalance, weight regain and knock-out experiments in animal models, but in the area of the effect of macronutrient composition on weight loss, controversy remains. Resistance to the idea comes from a perception that variable weight loss on isocaloric diets would somehow violate the laws of thermodynamics, that is, only caloric intake is important ("a calorie is a calorie". Previous explanations of how the phenomenon occurs, based on equilibrium thermodynamics, emphasized the inefficiencies introduced by substrate cycling and requirements for increased gluconeogenesis. Living systems, however, are maintained far from equilibrium, and metabolism is controlled by the regulation of the rates of enzymatic reactions. The principles of nonequilibrium thermodynamics which emphasize kinetic fluxes as well as thermodynamic forces should therefore also be considered. Here we review the principles of nonequilibrium thermodynamics and provide an approach to the problem of maintenance and change in body mass by recasting the problem of TAG accumulation and breakdown in the adipocyte in the language of nonequilibrium thermodynamics. We describe adipocyte physiology in terms of cycling between an efficient storage mode and a dissipative mode. Experimentally, this is measured in the rate of fatty acid flux and fatty acid oxidation. Hormonal levels controlled by changes in dietary carbohydrate regulate the relative contributions of the efficient and dissipative parts of the cycle. While no experiment exists that measures all relevant variables, the model is supported by evidence in the literature that 1 dietary carbohydrate, via its

  20. High-energy spectroscopy of lanthanide materials. Chapter 62

    International Nuclear Information System (INIS)

    Baer, Y.; Schneider, W.-D.

    1987-01-01

    This chapter starts with a treatment of the general principles of high-energy spectroscopic techniques and the basic concepts used to analyze the spectra. Then the different aspects of the electronic structure resulting from the presence of the 4f states, as revealed by spectroscopic techniques, are accounted for. The conventional and established 4f manifestations which are commonly quoted as fingerprints of the initial state are also briefly reviewed. A particular effort has been made to find out the merit and complementarity of the different spectroscopies applied to the elucidation of specific problems and the emphasis is put on the fact that a credible interpretation can only result from an unified model accounting for all observations. In this respect Ce plays a central role since, together with Yb, it offers the simplest initial situation but displays many unconventional manifestations which have been carefully investigated and can be accounted for by many-body calculations. (authhor). 204 refs.; 29 figs.; 2 tabs

  1. Energy loss and (de)coherence effects beyond eikonal approximation

    CERN Document Server

    Apolinário, Liliana; Milhano, Guilherme; Salgado, Carlos A.

    2014-01-01

    The parton branching process is known to be modified in the presence of a medium. Colour decoherence processes are known to determine the process of energy loss when the density of the medium is large enough to break the correlations between partons emitted from the same parent. In order to improve existing calculations that consider eikonal trajectories for both the emitter and the hardest emitted parton, we provide in this work, the calculation of all finite energy corrections for the gluon radiation off a quark in a QCD medium that exist in the small angle approximation and for static scattering centres. Using the path integral formalism, all particles are allowed to undergo Brownian motion in the transverse plane and the offspring allowed to carry an arbitrary fraction of the initial energy. The result is a general expression that contains both coherence and decoherence regimes that are controlled by the density of the medium and by the amount of broadening that each parton acquires independently.

  2. LRSPC, Proton High-Energy Loss in Matter

    International Nuclear Information System (INIS)

    2001-01-01

    1 - Description of program or function: The LRSPC program is designed to estimate the energy loss, due to ionization and excitation, and the range of charged particles passing through matter. The code treats protons in elements or mixtures composed of elements with atomic numbers ranging from 1 to 100. The results for protons are generally valid from 1 MeV to 100 GeV. The code may be extended to treat other charged particles such as muons, pions, hyperons, deuterons, tritons and alphas by changing the particle mass, charge and range at 2 MeV. 2 - Method of solution: Stopping power is calculated from the Bethe-Bloch equation with shell and density corrections included. Range is calculated by integrating the reciprocal of the stopping power from an initial value at 2 MeV. The K-shell correction is taken from Walske's data. The L-shell and higher shell corrections are adjusted to fit low energy measurements fro 30 elements. The density correction is calculated by a method similar to that of Sternheimer, differing chiefly in the large number of electron shells considered. LRSPC computes improved proton range and stopping power data for use in the proton penetration code, LPPC (CCC-0051). It is packages separately and may be requested independently. 3 - Restrictions on the complexity of the problem: Number of elements in mixture ≤ 10, Atomic number of element ≤ 100, Number of energy points ≤ 500

  3. Shell-Tunneling Spectroscopy of the Single-Particle Energy Levels of Insulating Quantum Dots

    NARCIS (Netherlands)

    Bakkers, E.P.A.M.; Hens, Z.; Zunger, A.; Franceschetti, A; Kouwenhoven, L.P.; Gurevich, L.; Vanmaekelbergh, D.

    2001-01-01

    The energy levels of CdSe quantum dots are studied by scanning tunneling spectroscopy. By varying the tip-dot distance, we switch from "shell-filling" spectroscopy (where electrons accumulate in the dot and experience mutual repulsion) to "shell-tunneling" spectroscopy (where electrons tunnel, one

  4. Electronic energy loss of the latent track in heavy ion-irradiated polyimide

    International Nuclear Information System (INIS)

    Sun Youmei; Liu Jie; Zhang Chonghong; Wang Zhiguang; Jin Yunfan; Duan Jinglai; Song Yin

    2005-01-01

    In the interaction process of a swift heavy ion (SHI) and polymer, a latent track with radius of several nanometers appears near the ion trajectory due to the dense ionization and excitation. To describe the role of electronic energy loss (dE/dX) e , multi-layer stacks (with different dE/dX) of polyimide (PI) films were irradiated by different SHIs (1.158 GeV Fe 56 and 1.755 GeV Xe 136 ) under vacuum at room temperature. Chemical changes of modified PI films were studied by Fourier Transform Infrared (FTIR) spectroscopy. The main feature of SHI irradiation is the degradation of the functional group and creation of alkyne. The chain disruption rate of PI was investigated in the fluence range from 1 x 10 11 to 6 x 10 12 ions/cm 2 and a wider energy stopping power range (2.2 to 5.2 keV/nm for Fe 56 ions and 8.6 to 11.3 keV/nm for Xe 136 ions). Alkyne formation was observed over the electronic energy loss range of interest. Assuming the saturated track model (the damage process only occur in a cylinder of area σ), the mean degradation and alkyne formation radii in tracks were deduced for Fe and Xe ion irradiation, respectively. The results were validated by the thermal spike model and the threshold electronic energy loss of track formation S et in PI was deduced. The analysis of the irradiated PI films shows that the predictions of the thermal spike model are in qualitative agreement with the curve shape of experimental results. (authors)

  5. Energy loss of heavy ion beams in plasma

    Energy Technology Data Exchange (ETDEWEB)

    Okada, T; Hotta, T [Tokyo Univ. of Agriculture and Technology, Koganei (Japan). Faculty of Technology

    1997-12-31

    The energy loss of heavy-ion beams (HIB) is studied by means of Vlasov theory and Particle-in-Cell (PIC) simulations in a plasma. The interaction of HIB with a plasma is of central importance for inertial confinement fusion (ICF). A number of studies on the HIB interaction with target plasma have been published. It is important for heavy-ion stopping that the effects of the non-linear interaction of HIB within the Vlasov theory are included. Reported are results of a numerical study of nonlinear effects to the stopping power for HIB in plasma. It is shown that the PIC simulations of collective effects of the stopping power are in a good agreement with the Vlasov theory. (author). 2 tabs., 1 fig., 5 refs.

  6. Production and energy loss of strange and heavy quarks

    International Nuclear Information System (INIS)

    2010-01-01

    Data taken over the last several years have demonstrated that RHIC has created a hot, dense medium with partonic degrees of freedom. Identified particle spectra at high transverse momentum (p T ) and heavy flavor that are thought to be well-calibrated probes thus serve as ideal tools to study the properties of the medium. We present p T distributions of particle ratios in p+p collisions from the STAR experiment to understand the particle production mechanisms. These measurements will also constrain fragmentation functions in hadron-hardon collisions. In heavy-ion collisions, we highlight (1) recent measurements of strange hadrons and heavy flavor decay electrons up to high p T to study jet interaction with the medium and explore partonic energy loss mechanisms, and (2) Υ and high p T J/ψ measurements to study the effect of color screening and other possible production mechanisms.

  7. Tensor decompositions for the analysis of atomic resolution electron energy loss spectra

    Energy Technology Data Exchange (ETDEWEB)

    Spiegelberg, Jakob; Rusz, Ján [Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala (Sweden); Pelckmans, Kristiaan [Department of Information Technology, Uppsala University, Box 337, S-751 05 Uppsala (Sweden)

    2017-04-15

    A selection of tensor decomposition techniques is presented for the detection of weak signals in electron energy loss spectroscopy (EELS) data. The focus of the analysis lies on the correct representation of the simulated spatial structure. An analysis scheme for EEL spectra combining two-dimensional and n-way decomposition methods is proposed. In particular, the performance of robust principal component analysis (ROBPCA), Tucker Decompositions using orthogonality constraints (Multilinear Singular Value Decomposition (MLSVD)) and Tucker decomposition without imposed constraints, canonical polyadic decomposition (CPD) and block term decompositions (BTD) on synthetic as well as experimental data is examined. - Highlights: • A scheme for compression and analysis of EELS or EDX data is proposed. • Several tensor decomposition techniques are presented for BSS on hyperspectral data. • Robust PCA and MLSVD are discussed for denoising of raw data.

  8. Structural Variations to a Donor Polymer with Low Energy Losses

    KAUST Repository

    Bazan, Guillermo C

    2017-08-01

    Two regioregular narrow band gap conjugated polymers with a D’-A-D-A repeat unit architecture, namely PIFCF and PSFCF, were designed and synthesized. Both polymers contain strictly organized fluorobenzo[c][1,2,5]thiadiazole (FBT) orientations and different solubilizing side chains for solution processing. Compared to the previously reported asymmetric pyridyl-[2,1,3]thiadiazole (PT) based regioregular polymer, namely PIPCP, PIFCF and PSFCF exhibit wider band gaps, tighter π-π stacking, and improved hole mobilities. When incorporated into solar cells with fullerene acceptors, the Eloss = Eg - eVoc values of PIFCF and PSFCF devices are increased compared to solar cells based on PIPCP. Determination of Ect in these solar cells reveals that, relative to PIPCP, PIFCF solar cells lose more energy from Eg - Ect, and PSFCF solar cells lose more energy from both Eg - Ect and Ect - eVoc. The close structural relationship between PIPCP and PIFCF provides an excellent framework to establish molecular features that impact the relationship between Eg and Ect. Theoretical calculations predict that Eloss of PIFCF:PC61BM would be higher than in the case of PIPCP:PC61BM, due to greater Eg - Ect. These findings provide insight into the design of high performance, low voltage loss photovoltaic polymeric materials with desirable optoelectronic properties.

  9. The effects of high electronic energy loss on the chemical modification of polyimide

    CERN Document Server

    SunYouMei; Jin Yun Fan; Liu Chang Long; LiuJie; Wang Zhi Guang; Zhang Qi; Zhu Zhi Yong

    2002-01-01

    In order to observe the role of electronic energy loss (dE/dX) sub e on chemical modification of polyimide (PI), the multi-layer stacks (corresponding to different dE/dX) were irradiated by different swift heavy ions (1.37 GeV Ar sup 4 sup 0 , 1.98 GeV Kr sup 8 sup 4 , 1.755 GeV Xe sup 1 sup 3 sup 6 and 2.636 GeV U sup 2 sup 3 sup 8) under vacuum and room temperature. The chemical changes of modified PI films were studied by Fourier transform infrared (FTIR) and ultraviolet/visible (UV/Vis) absorption spectroscopy. The degradation of PI was investigated in the fluence range from 1x10 sup 1 sup 0 to 5.5x10 sup 1 sup 2 ions/cm sup 2 and different electronic energy loss from 0.77 to 11.5 keV/nm. The FTIR results show the absorbance of the typical function group decrease exponentially as a function of fluence. The alkyne end group was found after irradiation and its formation radii were 5.6 and 5.9 nm corresponding to 8.8 and 11.5 keV/nm Xe irradiation respectively. UV/Vis analysis indicates the radiation induced...

  10. Surface vibrational spectroscopy (EELS)

    International Nuclear Information System (INIS)

    Okuyama, Hiroshi

    2006-01-01

    Adsorbed states of hydrogen on metal surfaces have been studied by means of electron energy loss spectroscopy (EELS). In this article, typical spectra and analysis as well as recent development are introduced. (author)

  11. Energy loss and charge exchange processes of high energy heavy ions channeled in crystals

    International Nuclear Information System (INIS)

    Poizat, J.C.; Andriamonje, S.; Anne, R.; Faria, N.V.d.C.; Chevallier, M.; Cohen, C.; Dural, J.; Farizon-Mazuy, B.; Gaillard, M.J.; Genre, R.; Hage-Ali, M.; Kirsch, R.; L'hoir, A.; Mory, J.; Moulin, J.; Quere, Y.; Remillieux, J.; Schmaus, D.; Toulemonde, M.

    1990-01-01

    The interaction of moving ions with single crystals is very sensitive to the orientation of the incident beam with respect to the crystalline directions of the target. Our experiments show that high energy heavy ion channeling deeply modifies their slowing down and charge exchange processes. This is due to the fact that channeled ions interact only with outershell target electrons, which means that the electron density they experience is very low and that the binding energy, and then the momentum distribution of these electrons, are quite different from the corresponding average values associated to random incidence. The two experimental studies presented here show the reduction of the energy loss rate for fast channeled heavy ions and illustrate the two aspects of channeling effects on charge exchange, the reduction of electron loss on one hand, and of electron capture on the other hand

  12. The Fracture Influence on the Energy Loss of Compressed Air Energy Storage in Hard Rock

    Directory of Open Access Journals (Sweden)

    Hehua Zhu

    2015-01-01

    Full Text Available A coupled nonisothermal gas flow and geomechanical numerical modeling is conducted to study the influence of fractures (joints on the complex thermohydromechanical (THM performance of underground compressed air energy storage (CAES in hard rock caverns. The air-filled chamber is modeled as porous media with high porosity, high permeability, and high thermal conductivity. The present analysis focuses on the CAES in hard rock caverns at relatively shallow depth, that is, ≤100 m, and the pressure in carven is significantly higher than ambient pore pressure. The influence of one discrete crack and multiple crackson energy loss analysis of cavern in hard rock media are carried out. Two conditions are considered during each storage and release cycle, namely, gas injection and production mass being equal and additional gas injection supplemented after each cycle. The influence of the crack location, the crack length, and the crack open width on the energy loss is studied.

  13. Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1968-01-01

    This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

  14. Spectroscopy

    CERN Document Server

    Walker, S

    1976-01-01

    The three volumes of Spectroscopy constitute the one comprehensive text available on the principles, practice and applications of spectroscopy. By giving full accounts of those spectroscopic techniques only recently introduced into student courses - such as Mössbauer spectroscopy and photoelectron spectroscopy - in addition to those techniques long recognised as being essential in chemistry teaching - sucha as e.s.r. and infrared spectroscopy - the book caters for the complete requirements of undergraduate students and at the same time provides a sound introduction to special topics for graduate students.

  15. Daily energy expenditure and physical activity measured in Parkinson's disease patients with and without weight loss

    Science.gov (United States)

    Patients with Parkinson's disease (PD) commonly exhibit weight loss, which investigators attribute to various factors, including elevated resting energy expenditure. We tested the hypothesis that daily energy expenditure (DEE) and its components, resting energy expenditure (REF) and physical activit...

  16. Daily energy expenditure, physical activity, and weight loss in Parkinson's disease patients

    Science.gov (United States)

    Patients with Parkinson's disease (PD) commonly exhibit weight loss (WL) which investigators attribute to various factors, including elevated energy expenditure. We tested the hypothesis that daily energy expenditure (DEE) and its components, resting energy expenditure (REE) and physical activity (P...

  17. Inelastic collisions of atomic particles at mean energies. Pt.1. Qualitative model of energy losses during a collision

    International Nuclear Information System (INIS)

    Pustovit, A.N.

    2005-01-01

    A new approach is proposed for description of the energy losses of mean-energy atomic particles during their interactions with atomic particles of solids. It is shown that all these interactions are inelastic ones and are determined by different scattering zones with different laws of energy loss dependences [ru

  18. Energy-loss measurement with the ZEUS Central Tracking Detector

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, D.

    2007-05-15

    The measurement of the specific energy loss due to ionisation, dE/dx, in a drift chamber is a very important tool for particle identification in final states of reactions between high energetic particles. Such identification requires a well understood dE/dx measurement including a precise knowledge of its uncertainties. Exploiting for the first time the full set of ZEUS data from the HERA operation between 1996 and 2005 twelve detector-related influences affecting the dE/dx measurement of the ZEUS Central Tracking Detector have been identified, separately studied and parameterised. A sophisticated iterative procedure has been developed to correct for these twelve effects, which takes into account the correlations between them. A universal parameterisation of the detector-specific Bethe-Bloch curve valid for all particle species has been extracted. In addition, the various contributions to the measurement uncertainty have been disentangled and determined. This yields the best achievable prediction for the single-track dE/dx resolution. For both the analysis of the measured data and the simulation of detector performance, the detailed understanding of the measurement and resolution of dE/dx gained in this work provides a tool with optimum power for particle identification in a physics studies. (orig.)

  19. Energy-loss measurement with the ZEUS Central Tracking Detector

    International Nuclear Information System (INIS)

    Bartsch, D.

    2007-05-01

    The measurement of the specific energy loss due to ionisation, dE/dx, in a drift chamber is a very important tool for particle identification in final states of reactions between high energetic particles. Such identification requires a well understood dE/dx measurement including a precise knowledge of its uncertainties. Exploiting for the first time the full set of ZEUS data from the HERA operation between 1996 and 2005 twelve detector-related influences affecting the dE/dx measurement of the ZEUS Central Tracking Detector have been identified, separately studied and parameterised. A sophisticated iterative procedure has been developed to correct for these twelve effects, which takes into account the correlations between them. A universal parameterisation of the detector-specific Bethe-Bloch curve valid for all particle species has been extracted. In addition, the various contributions to the measurement uncertainty have been disentangled and determined. This yields the best achievable prediction for the single-track dE/dx resolution. For both the analysis of the measured data and the simulation of detector performance, the detailed understanding of the measurement and resolution of dE/dx gained in this work provides a tool with optimum power for particle identification in a physics studies. (orig.)

  20. Electronic energy loss of fast molecules in matter

    International Nuclear Information System (INIS)

    Steinbeck, J.

    1975-06-01

    In high velocity collisions of molecular ions the correlated motion influence of the ion cores on the electronic energy loss is investigated. The stopping power in first Born approximation for a random arrangement of target atoms can be formulated in terms of the inelastic electronic structure factor. In treating the target atoms in Hartree-Fock approximation each electron can be regarded as stopping the ion independent of all other electrons without restriction by the Pauli principle. A second equivalent formulation of the stopping power leads to the dielectric function of the target. The results are applied to the stopping of H 2 + -ions. For vanishing distance between the two protons the stopping power per particle is twice that for single proton collisions. For distances in the order of the Bohr radius the correlated stopping power may even be smaller than for uncorrelated protons. With increasing distances the correlation influence vanishes. The stopping of H 2 + -ions in C, Si and Ge is discussed using Clementi wave functions for the core electrons and a free electron approximation with Lindhard's dielectric function for the valence electrons. The comparison with the only experimental result available for H 2 + in C at 300 keV yields qualitative agreement. (orig.) [de

  1. Bipolar energy-loss measurements on cryostable, low-loss conductors

    Energy Technology Data Exchange (ETDEWEB)

    Wollan, J.J.

    1981-01-01

    Losses have been measured on a prototype conductor for the 20 MJ coil for conditions which simulate closely the actual coil field sweep. The data on the prototype II conductor indicates coil losses which exceed the coil specification. The application of certain correction factors reduces the projected losses within the specification for a 2 s reversal but not for a 1 s reversal. Verification of these corrections await measurements on the actual strand and completion of coil construction and testing.

  2. The Electronic Structure of C59N and Its AxC59N (A=K, Rb, Cs) Salts from High Energy Spectroscopy

    NARCIS (Netherlands)

    Golden, M.S.; Pichler, T.; Knupfer, M.; Friedlein, R.; Haffner, S.; Fink, J.; Andreoni, W.; Curioni, A.; Keshavarz-K, M.; Bellavia-Lund, C.; Sastre, A.; Hummelen, J.-C.; Wudl, F.

    1998-01-01

    Using a combination of results from photoemission, electron energy-loss spectroscopy in transmission and gradient-corrected density functional calculations, we have examined the effects of chemical substitution of N for C in the dimerised heterofullerene (C59N)2. We show that there is a new HOMO

  3. Study of high energy ion loss during hydrogen minority heating in TFTR

    International Nuclear Information System (INIS)

    Park, J.; Zweben, S.J.

    1994-03-01

    High energy ion loss during hydrogen minority ICRF heating is measured and compared with the loss of the D-D fusion products. During H minority heating a relatively large loss of high energy ions is observed at 45 degrees below the outer midplane, with or without simultaneous NBI heating. This increase is most likely due to a loss of the minority tail protons, a possible model for this process is described

  4. Electron-energy-loss and optical-transmittance investigation of Bi2Sr2CaCu2O8

    International Nuclear Information System (INIS)

    Wang, Y.; Feng, G.; Ritter, A.L.

    1990-01-01

    The energy-loss function Im(-1/ε) of Bi 2 Sr 2 CaCu 2 O 8 has been measured over the range E loss =0.8 to 80 eV by transmission electron-energy-loss spectroscopy (EELS) (nonimaging). The energy and momentum resolution were 0.1 eV and 0.04 A -1 , respectively. The low-energy spectra (E loss ≤3 eV) were studied as a function of momentum transfer (0.1 A -1 ≤q≤0.3 A -1 ). A well-defined peak in the loss function at E loss ∼1 eV is observed to disperse with momentum proportional to q 2 . This excitation is analyzed in terms of both an intracell, charge-transfer exciton model and the free-carrier (plasmon) model. The derived effective mass of the exciton m tot /m congruent 1.0 is far too small for a localized exciton. Using the free-carrier model and random-phase-approximation expressions for the dispersion coefficient, the carrier density and carrier effective mass can be determined separately. From our data and similar measurements by Nuecker et al. [Phys. Rev. B 39, 12 379 (1989)], it is found that the effective mass roughly scales with carrier density. A heuristic model is introduced based on the assumption that low-energy gaps exist in portions of the Fermi surface due to structural instabilities. The model suggests how the effective mass could appear to scale with carrier density and why a single Drude term (with frequency-independent effective mass) does not describe the mid- to far-infrared optical spectra. Finally, the optical transmittance of the EELS sample was measured and the spectra analyzed in terms of the free-carrier model

  5. Experimental investigation of the trapping and energy loss mechanisms of intense relativistic electron rings in hydrogen gas and plasma

    International Nuclear Information System (INIS)

    Smith, A.C. Jr.

    1977-01-01

    The results of an experimental study on the trapping and energy loss mechanisms of intense, relativistic electron rings confined in Astron-like magnetic field geometries are presented. The work is subdivided into four sections: gas trapping; average ring electron energetics; plasma trapping, and hollow-beam cusp-injection into gas and plasma. The mechanisms by which the injected beam coalesces into a current ring in the existing Cornell RECE-Berta facility are considered. To investigate the nature of ring electron energy loss mechanisms following completion of the trapping process, a diagnostic was developed utilizing multi-foil X-ray absorption spectroscopy to analyze the Bremsstrahlung generated by the electrons as they impinge upon a thin tungsten wire target suspended in the circulating current. Finally, a set of preliminary experimental results is presented in which an annular electron beam was passed through a coaxial, non-adiabatic magnetic cusp located at one end of a magnetic mirror well

  6. Cascade-probabilistic function with taking unto account energy losses of ions. Chapter 3

    International Nuclear Information System (INIS)

    1998-01-01

    Mathematical simulation of cascade-probabilistic functions (CPF) for ions with taking into account of energy losses is carried out. Recommendations for CPF calculation on computer are given. Influence of both the interaction number on CPF domain and the interaction depth on CPF domain are determined. Contribution of energy losses into simplest CPF is estimated. Algorithm of radiation defects concentration calculation under ion irradiation with taking into consideration energy losses is cited

  7. Acute visual loss and intraretinal hemorrhages associated to energy drink consumption.

    Science.gov (United States)

    Pagano, Christina W; Wu, Max; Wu, Lihteh

    2017-12-01

    To report the association of acute visual loss secondary to intraretinal hemorrhages and energy drink consumption. Case report and literature review. A 48-year-old hypertensive man developed an elevation in systemic blood pressure, tachycardia, and acute visual loss secondary to intraretinal hemorrhages shortly after drinking several cans of energy drinks. High consumption of energy drinks may lead to intraretinal hemorrhages and acute visual loss.

  8. Far-from-equilibrium heavy quark energy loss at strong coupling

    CERN Document Server

    Chesler, Paul; Rajagopal, Krishna

    2013-01-01

    We study the energy loss of a heavy quark propagating through the matter produced in the collision of two sheets of energy [1]. Even though this matter is initially far-from-equilibrium we find that, when written in terms of the energy density, the equilibrium expression for heavy quark energy loss describes most qualitative features of our results well. At later times, once a plasma described by viscous hydrodynamics has formed, the equilibrium expression describes the heavy quark energy loss quantitatively. In addition to the drag force that makes it lose energy, a quark moving through the out-of-equilibrium matter feels a force perpendicular to its velocity.

  9. Synthesis of Pt nanoparticles and their burrowing into Si due to synergistic effects of ion beam energy losses

    Directory of Open Access Journals (Sweden)

    Pravin Kumar

    2014-10-01

    Full Text Available We report the synthesis of Pt nanoparticles and their burrowing into silicon upon irradiation of a Pt–Si thin film with medium-energy neon ions at constant fluence (1.0 × 1017 ions/cm2. Several values of medium-energy neon ions were chosen in order to vary the ratio of the electronic energy loss to the nuclear energy loss (Se/Sn from 1 to 10. The irradiated films were characterized using Rutherford backscattering spectroscopy (RBS, atomic force microscopy (AFM, scanning electron microscopy (SEM, X-ray diffraction (XRD and high resolution transmission electron microscopy (HRTEM. A TEM image of a cross section of the film irradiated with Se/Sn = 1 shows ≈5 nm Pt NPs were buried up to ≈240 nm into the silicon. No silicide phase was detected in the XRD pattern of the film irradiated at the highest value of Se/Sn. The synergistic effect of the energy losses of the ion beam (molten zones are produced by Se, and sputtering and local defects are produced by Sn leading to the synthesis and burrowing of Pt NPs is evidenced. The Pt NP synthesis mechanism and their burrowing into the silicon is discussed in detail.

  10. On the Trade-off between Energy Consumption and Food Quality Loss in Supermarket Refrigeration Systems

    DEFF Research Database (Denmark)

    Cai, Junping; Jensen, Jørgen Bauck; Skogestad, Sigurd

    2008-01-01

    This paper studies the trade-off between energy consumption and food quality loss, at varying ambient conditions, in supermarket refrigeration systems. Compared with the traditional operation with pressure control, a large potential for energy savings without extra loss of food quality is demonst......This paper studies the trade-off between energy consumption and food quality loss, at varying ambient conditions, in supermarket refrigeration systems. Compared with the traditional operation with pressure control, a large potential for energy savings without extra loss of food quality...

  11. Transmitted ion energy loss distributions to detect cluster formation in silicon

    International Nuclear Information System (INIS)

    Selen, L.J.M.; Loon, A. van; IJzendoorn, L.J. van; Voigt, M.J.A. de

    2002-01-01

    The energy loss distribution of ions transmitted through a 5.7±0.2 μm thick Si crystal was measured and simulated with the Monte Carlo channeling simulation code FLUX. A general resemblance between the measured and simulated energy loss distributions was obtained after incorporation of an energy dependent energy loss in the simulation program. The energy loss calculations are used to investigate the feasibility to detect the presence of light element dopant clusters in a host crystal from the shape of the energy loss distribution, with transmission ion channeling. A curved crystal structure is used as a model for a region in the host crystal with clusters. The presence of the curvature does have a large influence on the transmitted energy distribution, which offers the possibility to determine the presence of dopant clusters in a host crystal with transmission ion channeling

  12. Towards atomically resolved EELS elemental and fine structure mapping via multi-frame and energy-offset correction spectroscopy.

    Science.gov (United States)

    Wang, Yi; Huang, Michael R S; Salzberger, Ute; Hahn, Kersten; Sigle, Wilfried; van Aken, Peter A

    2018-01-01

    Electron energy-loss spectroscopy and energy-dispersive X-ray spectroscopy are two of the most common means for chemical analysis in the scanning transmission electron microscope. The marked progress of the instrumentation hardware has made chemical analysis at atomic resolution readily possible nowadays. However, the acquisition and interpretation of atomically resolved spectra can still be problematic due to image distortions and poor signal-to-noise ratio of the spectra, especially for investigation of energy-loss near-edge fine structures. By combining multi-frame spectrum imaging and automatic energy-offset correction, we developed a spectrum imaging technique implemented into customized DigitalMicrograph scripts for suppressing image distortions and improving the signal-to-noise ratio. With practical examples, i.e. SrTiO 3 bulk material and Sr-doped La 2 CuO 4 superlattices, we demonstrate the improvement of elemental mapping and the EELS spectrum quality, which opens up new possibilities for atomically resolved EELS fine structure mapping. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  13. Steady-state heat losses in pipes for low-energy district heating

    DEFF Research Database (Denmark)

    Dalla Rosa, Alessandro; Li, Hongwei; Svendsen, Svend

    2010-01-01

    The synergy between highly energy efficient buildings and low-energy district heating (DH) systems is a promising concept for the optimal integration of energy saving policies and energy supply systems based on renewable energy (RE). Distribution heat losses represent a key factor in the design o...

  14. Self-Directed Weight Loss Strategies: Energy Expenditure Due to Physical Activity Is Not Increased to Achieve Intended Weight Loss

    Directory of Open Access Journals (Sweden)

    Ulf Elbelt

    2015-07-01

    Full Text Available Reduced physical activity and almost unlimited availability of food are major contributors to the development of obesity. With the decline of strenuous work, energy expenditure due to spontaneous physical activity has attracted increasing attention. Our aim was to assess changes in energy expenditure, physical activity patterns and nutritional habits in obese subjects aiming at self-directed weight loss. Methods: Energy expenditure and physical activity patterns were measured with a portable armband device. Nutritional habits were assessed with a food frequency questionnaire. Results: Data on weight development, energy expenditure, physical activity patterns and nutritional habits were obtained for 105 patients over a six-month period from an initial cohort of 160 outpatients aiming at weight loss. Mean weight loss was −1.5 ± 7.0 kg (p = 0.028. Patients with weight maintenance (n = 75, with substantial weight loss (>5% body weight, n = 20 and with substantial weight gain (>5% body weight, n = 10 did not differ in regard to changes of body weight adjusted energy expenditure components (total energy expenditure: −0.2 kcal/kg/day; non-exercise activity thermogenesis: −0.3 kcal/kg/day; exercise-related activity thermogenesis (EAT: −0.2 kcal/kg/day or patterns of physical activity (duration of EAT: −2 min/day; steps/day: −156; metabolic equivalent unchanged measured objectively with a portable armband device. Self-reported consumption frequency of unfavorable food decreased significantly (p = 0.019 over the six-month period. Conclusions: An increase in energy expenditure or changes of physical activity patterns (objectively assessed with a portable armband device are not employed by obese subjects to achieve self-directed weight loss. However, modified nutritional habits could be detected with the use of a food frequency questionnaire.

  15. Self-Directed Weight Loss Strategies: Energy Expenditure Due to Physical Activity Is Not Increased to Achieve Intended Weight Loss.

    Science.gov (United States)

    Elbelt, Ulf; Schuetz, Tatjana; Knoll, Nina; Burkert, Silke

    2015-07-16

    Reduced physical activity and almost unlimited availability of food are major contributors to the development of obesity. With the decline of strenuous work, energy expenditure due to spontaneous physical activity has attracted increasing attention. Our aim was to assess changes in energy expenditure, physical activity patterns and nutritional habits in obese subjects aiming at self-directed weight loss. Energy expenditure and physical activity patterns were measured with a portable armband device. Nutritional habits were assessed with a food frequency questionnaire. Data on weight development, energy expenditure, physical activity patterns and nutritional habits were obtained for 105 patients over a six-month period from an initial cohort of 160 outpatients aiming at weight loss. Mean weight loss was -1.5 ± 7.0 kg (p = 0.028). Patients with weight maintenance (n = 75), with substantial weight loss (>5% body weight, n = 20) and with substantial weight gain (>5% body weight, n = 10) did not differ in regard to changes of body weight adjusted energy expenditure components (total energy expenditure: -0.2 kcal/kg/day; non-exercise activity thermogenesis: -0.3 kcal/kg/day; exercise-related activity thermogenesis (EAT): -0.2 kcal/kg/day) or patterns of physical activity (duration of EAT: -2 min/day; steps/day: -156; metabolic equivalent unchanged) measured objectively with a portable armband device. Self-reported consumption frequency of unfavorable food decreased significantly (p = 0.019) over the six-month period. An increase in energy expenditure or changes of physical activity patterns (objectively assessed with a portable armband device) are not employed by obese subjects to achieve self-directed weight loss. However, modified nutritional habits could be detected with the use of a food frequency questionnaire.

  16. CEBAF at higher energies: Working group report on hadron spectroscopy and production

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, T. [Oak Ridge National Laboratory, TN (United States)]| [Univ. of Tennessee, Knoxville (United States); Napolitano, J. [Rensselaer Polytechnic Inst., Troy, NY (United States)

    1994-04-01

    This report summarizes topics in hadron spectroscopy and production which could be addressed at CEBAF with an energy upgrade to E{sub {gamma}} = 8 GeV and beyond. The topics discussed include conventional meson and baryon spectrocopy, spectroscopy of exotica (especially molecules and hybrids), CP and CPT tests using {phi} mesons, and new detector and accelerator options.

  17. Effect of laser pulse energies in laser induced breakdown spectroscopy in double-pulse configuration

    International Nuclear Information System (INIS)

    Benedetti, P.A.; Cristoforetti, G.; Legnaioli, S.; Palleschi, V.; Pardini, L.; Salvetti, A.; Tognoni, E.

    2005-01-01

    In this paper, the effect of laser pulse energy on double-pulse laser induced breakdown spectroscopy signal is studied. In particular, the energy of the first pulse has been changed, while the second pulse energy is held fixed. A systematic study of the laser induced breakdown spectroscopy signal dependence on the interpulse delay is performed, and the results are compared with the ones obtained with a single laser pulse of energy corresponding to the sum of the two pulses. At the same time, the crater formed at the target surface is studied by video-confocal microscopy, and the variation in crater dimensions is correlated to the enhancement of the laser induced breakdown spectroscopy signal. The results obtained are consistent with the interpretation of the double-pulse laser induced breakdown spectroscopy signal enhancement in terms of the changes in ambient gas pressure produced by the shock wave induced by the first laser pulse

  18. Studies on low energy ion-atom collisions by means of electron-spectroscopy

    International Nuclear Information System (INIS)

    Hirosi Suzuki

    1991-01-01

    The typical results of studies on autoionization processes produced by low energy ion-atom collisions are given by means of the ejected electron spectroscopy, which have been performed by Atomic Physics Group of Sophia University

  19. Exploring energy loss by vector flow mapping in children with ventricular septal defect: Pathophysiologic significance.

    Science.gov (United States)

    Honda, Takashi; Itatani, Keiichi; Takanashi, Manabu; Kitagawa, Atsushi; Ando, Hisashi; Kimura, Sumito; Oka, Norihiko; Miyaji, Kagami; Ishii, Masahiro

    2017-10-01

    Vector flow mapping is a novel echocardiographic flow visualization method, and it has enabled us to quantitatively evaluate the energy loss in the left ventricle (intraventricular energy loss). Although intraventricular energy loss is assumed to be a part of left ventricular workload itself, it is unclear what this parameter actually represents. The aim of the present study was to elucidate the characteristics of intraventricular energy loss. We enrolled 26 consecutive children with ventricular septal defect (VSD). On echocardiography vector flow mapping, intraventricular energy loss was measured in the apical 3-chamber view. We measured peak energy loss and averaged energy loss in the diastolic and systolic phases, and subsequently compared these parameters with catheterization parameters and serum brain natrium peptide (BNP) level. Diastolic, peak, and systolic energy loss were strongly and positively correlated with right ventricular systolic pressure (r=0.76, 0.68, and 0.56, p<0.0001, = 0.0001, and 0.0029, respectively) and right ventricular end diastolic pressure (r=0.55, 0.49, and 0.49, p=0.0038, 0.0120, and 0.0111, respectively). In addition, diastolic, peak, and systolic energy loss were significantly correlated with BNP (r=0.75, 0.69 and 0.49, p<0.0001, < 0.0001, and=0.0116, respectively). In children with VSD, elevated right ventricular pressure is one of the factors that increase energy loss in the left ventricle. The results of the present study encourage further studies in other study populations to elucidate the characteristics of intraventricular energy loss for its possible clinical application. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Trajectory-dependent energy loss for swift He atoms axially scattered off a silver surface

    Energy Technology Data Exchange (ETDEWEB)

    Ríos Rubiano, C.A. [Instituto de Astronomía y Física del Espacio (CONICET-UBA), Casilla de correo 67, sucursal 28, 1428 Buenos Aires (Argentina); Bocan, G.A. [Centro Atómico Bariloche, Comisión Nacional de Energía Ató mica, and Consejo Nacional de Investigaciones Científicas y Técnicas, S.C. de Bariloche, Río Negro (Argentina); Juaristi, J.I. [Departamento de Física de Materiales, Facultad de Químicas, UPV/EHU, 20018 San Sebastián (Spain); Donostia International Physics Center (DIPC) and Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), 20018 San Sebastián (Spain); Gravielle, M.S., E-mail: msilvia@iafe.uba.ar [Instituto de Astronomía y Física del Espacio (CONICET-UBA), Casilla de correo 67, sucursal 28, 1428 Buenos Aires (Argentina)

    2014-12-01

    Angle- and energy-loss-resolved distributions of helium atoms grazingly scattered from a Ag(110) surface along low indexed crystallographic directions are investigated considering impact energies in the few keV range. Final projectile distributions are evaluated within a semi-classical formalism that includes dissipative effects due to electron–hole excitations through a friction force. For mono-energetic beams impinging along the [11{sup ¯}0],[11{sup ¯}2] and [001] directions, the model predicts the presence of multiple peak structures in energy-loss spectra. Such structures provide detailed information about the trajectory-dependent energy loss. However, when the experimental dispersion of the incident beam is taken into account, these energy-loss peaks are completely washed out, giving rise to a smooth energy-loss distribution, in fairly good agreement with available experimental data.

  1. Energy Losses through Unharnessed Biomass in South- Eastern ...

    African Journals Online (AJOL)

    Nekky Umera

    energy and which can be made available to both the rural and urban areas of the ... when burnt, it produces carbon (iv) oxide, which results in the ... attitude of exploiting the much available and cleaner alternative energy ... human wastes.

  2. Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

  3. Photoelectron spectroscopy on the charge reorganization energy and small polaron binding energy of molecular film

    Energy Technology Data Exchange (ETDEWEB)

    Kera, Satoshi, E-mail: kera@ims.ac.jp [Institute for Molecular Science, Myodaiji, Okazaki 444-8585 (Japan); Department of Nanomaterial Science, Graduate School of Advanced Integration Science, Chiba University, Inage-ku, Chiba 263-8522 (Japan); Ueno, Nobuo [Department of Nanomaterial Science, Graduate School of Advanced Integration Science, Chiba University, Inage-ku, Chiba 263-8522 (Japan)

    2015-10-01

    Understanding of electron-phonon coupling as well as intermolecular interaction is required to discuss the mobility of charge carrier in functional molecular solids. This article summarizes recent progress in direct measurements of valence hole-vibration coupling in ultrathin films of organic semiconductors by using ultraviolet photoelectron spectroscopy (UPS). The experimental study of hole-vibration coupling of the highest occupied molecular orbital (HOMO) state in ordered monolayer film by UPS is essential to comprehend hole-hopping transport and small-polaron related transport in organic semiconductors. Only careful measurements can attain the high-resolution spectra and provide key parameters in hole-transport dynamics, namely the charge reorganization energy and small polaron binding energy. Analyses methods of the UPS HOMO fine feature and resulting charge reorganization energy and small polaron binding energy are described for pentacene and perfluoropentacene films. Difference between thin-film and gas-phase results is discussed by using newly measured high-quality gas-phase spectra of pentacene. Methodology for achieving high-resolution UPS measurements for molecular films is also described.

  4. Observations of discrete energy loss effects in spectra of positrons reflected from solid surfaces

    International Nuclear Information System (INIS)

    Dale, J.M.; Hulett, L.D.; Pendyala, S.

    1980-01-01

    Surfaces of tungsten and silicon have been bombarded with monoenergetic beams of positrons and electrons. Spectra of reflected particles show energy loss tails with discrete peaks at kinetic energies about 15 eV lower than that of the elastic peaks. In the higher energy loss range for tungsten, positron spectra show fine structure that is not apparent in the electron spectra. This suggests that the positrons are losing energy through mechanisms different from that of the electrons

  5. Improving a radiative plus collisional energy loss model for application to RHIC and LHC

    International Nuclear Information System (INIS)

    Wicks, Simon; Gyulassy, Miklos

    2007-01-01

    With the QGP opacity computed perturbatively and with the global entropy constraints imposed by the observed dN ch /dy ∼ 1000, radiative energy loss alone cannot account for the observed suppression of single non-photonic electrons. Collisional energy loss is comparable in magnitude to radiative loss for both light and heavy jets. Two aspects that significantly affect the collisional energy loss are examined: the role of fluctuations and the effect of introducing a running QCD coupling as opposed to the fixed α s = 0.3 used previously

  6. Electromagnetic therapeutic coils design to reduce energy loss

    Directory of Open Access Journals (Sweden)

    Syrek Przemyslaw

    2016-01-01

    Full Text Available The article introduces the problem of power loss reduction in applicators used in magnetotherapy. To generate magnetic field whose distribution is optimal and to reduce the power loss, the authors establish a set of parameters to evaluate the model of device. Results make it possible to infer that the real power input necessary to operate the magnetic field generator properly may vary significantly depending on construction and localization. The issues raised in this paper should be treated as a basis for further discussion on the construction of applicators used, e.g., in Transcranial Magnetic Stimulation.

  7. Fecal energy losses in enterally fed intensive care patients: An explorative study using bomb calorimetry

    NARCIS (Netherlands)

    Strack van Schijndel, R.J.M.; Wierdsma, N.J.; van Heijningen, E.M.B.; Weijs, P.J.M.; de Groot, S.D.W.; Girbes, A.R.J.

    2006-01-01

    Background & Aims: Early enteral nutrition and tailored supply of nutrients have become standard in most of the intensive care units (ICU). So far little attention has been given to losses of energy in the stools. The purpose of this explorative study was to evaluate the energy losses of patients

  8. REFINED ALGORITHMS OF ELECTRICAL ENERGY LOSSES CALCULATION IN 0,38 KV NETWORKS IN REAL TIME

    Directory of Open Access Journals (Sweden)

    Miroshnyk A.

    2010-08-01

    Full Text Available An approach for closer definition of electrical energy losses size in air lines due to the accounting of environment temperature influence and flowing current size on the wire resistance is offered. Multifunctional microprocessor devices for energy losses calculation are elaborated.

  9. Skipping meals and alcohol consumption. The regulation of energy intake and expenditure among weight loss participants.

    Science.gov (United States)

    Carels, Robert A; Young, Kathleen M; Coit, Carissa; Clayton, Anna Marie; Spencer, Alexis; Wagner, Marissa

    2008-11-01

    Research suggests that specific eating patterns (e.g., eating breakfast) may be related to favorable weight status. This investigation examined the relationship between eating patterns (i.e., skipping meals; consuming alcohol) and weight loss treatment outcomes (weight loss, energy intake, energy expenditure, and duration of exercise). Fifty-four overweight or obese adults (BMI> or =27 kg/m(2)) participated in a self-help or therapist-assisted weight loss program. Daily energy intake from breakfast, lunch, dinner, and alcoholic beverages, total daily energy intake, total daily energy expenditure, physical activity, and weekly weight loss were assessed. On days that breakfast or dinner was skipped, or alcoholic beverages were not consumed, less total daily energy was consumed compared to days that breakfast, dinner, or alcoholic beverages were consumed. On days that breakfast or alcohol was consumed, daily energy expenditure (breakfast only) and duration of exercise were higher compared to days that breakfast or alcohol was not consumed. Individuals who skipped dinner or lunch more often had lower energy expenditure and exercise duration than individuals who skipped dinner or lunch less often. Individuals who consumed alcohol more often had high daily energy expenditure than individuals who consumed alcohol less often. Skipping meals or consuming alcoholic beverages was not associated with weekly weight loss. In this investigation, weight loss program participants may have compensated for excess energy intake from alcoholic beverages and meals with greater daily energy expenditure and longer exercise duration.

  10. Resistant starch and energy balance: impact on weight loss and maintenance.

    Science.gov (United States)

    Higgins, Janine A

    2014-01-01

    The obesity epidemic has prompted researchers to find effective weight-loss and maintenance tools. Weight loss and subsequent maintenance are reliant on energy balance--the net difference between energy intake and energy expenditure. Negative energy balance, lower intake than expenditure, results in weight loss whereas positive energy balance, greater intake than expenditure, results in weight gain. Resistant starch has many attributes, which could promote weight loss and/or maintenance including reduced postprandial insulinemia, increased release of gut satiety peptides, increased fat oxidation, lower fat storage in adipocytes, and preservation of lean body mass. Retention of lean body mass during weight loss or maintenance would prevent the decrease in basal metabolic rate and, therefore, the decrease in total energy expenditure, that occurs with weight loss. In addition, the fiber-like properties of resistant starch may increase the thermic effect of food, thereby increasing total energy expenditure. Due to its ability to increase fat oxidation and reduce fat storage in adipocytes, resistant starch has recently been promoted in the popular press as a "weight loss wonder food". This review focuses on data describing the effects of resistant starch on body weight, energy intake, energy expenditure, and body composition to determine if there is sufficient evidence to warrant these claims.

  11. Positron annihilation spectroscopy using high-energy photons

    International Nuclear Information System (INIS)

    Butterling, Maik; Jungmann, Marco; Krause-Rehberg, Reinhard; Krille, Arnold; Anwand, Wolfgang; Brauer, Gerhard; Cowan, Thomas E.; Hartmann, Andreas; Kosev, Krasimir; Schwengner, Ronald; Wagner, Andreas

    2010-01-01

    The superconducting electron accelerator ELBE (Electron Linac with high Brilliance and low Emittance) at the Research Centre Dresden-Rossendorf (Germany) serves as a high-intensity bremsstrahlung photon-source delivering a pulsed beam (26 MHz) with very short bunches (<5 ps). The photons are being converted into positrons by means of pair production inside the target material thus forming an intense positron source. The accelerator machine pulse is used as time reference allowing positron lifetime spectroscopy. We performed positron annihilation spectroscopy by pair production in different sample materials and used coincidence techniques to reduce the background due to scattered photons significantly in order resulting in spectra of extraordinary high quality. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  12. Energy Density and Weight Loss: Feel Full on Fewer Calories

    Science.gov (United States)

    ... Behavior. 2009;97:609. Rouhani MH, et al. Associations between dietary energy density and obesity: A systematic review and meta-analysis of observational studies. Nutrition. 2016;32:1037. Stelmach-Mardas M, et al. Link between food energy density and body weight changes in obese ...

  13. Energy losses in magnetically insulated transmission lines due to microparticles

    International Nuclear Information System (INIS)

    Gray, E.W.; Stinnett, R.W.

    1987-01-01

    We discuss the effects of high-velocity and hypervelocity microparticles in the magnetically insulated transmission lines of multiterawatt accelerators used for particle beam fusion and radiation effects simulation. These microparticles may be a possible source for plasma production near the anode and cathode in early stages of the voltage pulse, and current carriers during and after the power pulse, resulting in power flow losses. Losses in the current pulse, due to microparticles, are estimated to be approximately 12 mA/cm 2 (0.3 kA) as a lower limit, and --0.3 A/cm 2 (7.2 kA) for microparticle initiated, anode plasma positive ion transport. We have calculated the velocities reached by these microparticles and the effects on them of Van der Waals forces. Field emission from the particles and their effects on cathode and anode plasma formation have been examined. Particle collision with the electrodes is also examined in terms of plasma production, as in the electron deposition in the particles in transit across the anode-cathode gap. Blistering of the electrode surface, thought to be due to H - bombardment was also observed and appears to be consistent with losses due to negative ions previously reported by J. P. VanDevender, R. W. Stinnett, and R. J. Anderson [App. Phys. Lett. 38, 229 (1981)

  14. Energy loss and straggling of MeV ions through biological samples

    International Nuclear Information System (INIS)

    Ma Lei; Wang Yugang; Xue Jianming; Chen Qizhong; Zhang Weiming; Zhang Yanwen

    2007-01-01

    Energy loss and energy straggling of energetic ions through natural dehydrated biological samples were investigated using transmission technique. Biological samples (onion membrane, egg coat, and tomato coat) with different mass thickness were studied, together with Mylar for comparison. The energy loss and energy straggling of MeV H and He ions after penetrating the biological and Mylar samples were measured. The experimental results show that the average energy losses of MeV ions through the biological samples are consistent with SRIM predictions; however, large deviation in energy straggling is observed between the measured results and the SRIM predictions. Taking into account inhomogeneity in mass density and structure of the biological sample, an energy straggling formula is suggested, and the experimental energy straggling values are well predicted by the proposed formula

  15. spectroscopy

    African Journals Online (AJOL)

    Aghomotsegin

    2015-10-14

    Oct 14, 2015 ... characterized by using phenotypic, API and Fourier transform infrared (FTIR) spectroscopy methods. One hundred and fifty-seven (157) strains were isolated from 13 cheese samples, and identification test was performed for 83 strains. At the end of the study, a total of 22 Lactococcus sp., 36 Enterecoccus ...

  16. Evolutionary developments in x ray and electron energy loss microanalysis instrumentation for the analytical electron microscope

    Science.gov (United States)

    Zaluzec, Nester J.

    Developments in instrumentation for both X ray Dispersive and Electron Energy Loss Spectroscopy (XEDS/EELS) over the last ten years have given the experimentalist a greatly enhanced set of analytical tools for characterization. Microanalysts have waited for nearly two decades now in the hope of getting a true analytical microscope and the development of 300 to 400 kV instruments should have allowed us to attain this goal. Unfortunately, this has not generally been the case. While there have been some major improvements in the techniques, there has also been some devolution in the modern AEM (Analytical Electron Microscope). In XEDS, the majority of today's instruments are still plagued by the hole count effect, which was first described in detail over fifteen years ago. The magnitude of this problem can still reach the 20 percent level for medium atomic number species in a conventional off-the-shelf intermediate voltage AEM. This is an absurd situation and the manufacturers should be severely criticized. Part of the blame, however, also rests on the AEM community for not having come up with a universally agreed upon standard test procedure. Fortunately, such a test procedure is in the early stages of refinement. The proposed test specimen consists of an evaporated Cr film approx. 500 to 1000A thick supported upon a 3mm diameter Molybdenum 200 micron aperture.

  17. Energy loss mechanism for suspended micro- and nanoresonators due to the Casimir force

    OpenAIRE

    Gusso, André

    2011-01-01

    A so far not considered energy loss mechanism in suspended micro- and nanoresonators due to noncontact acoustical energy loss is investigated theoretically. The mechanism consists on the conversion of the mechanical energy from the vibratory motion of the resonator into acoustic waves on large nearby structures, such as the substrate, due to the coupling between the resonator and those structures resulting from the Casimir force acting over the separation gaps. Analytical expressions for the ...

  18. Electrical energy prices and losses respect to Turkish social-economic situations

    International Nuclear Information System (INIS)

    Berktay, Ali; Demirbas, Ayhan; Kocak, Saim; Nas, Bilgehan

    2004-01-01

    Electricity is a basic part of nature and it is one of the most widely used forms of energy. Electricity, which is a secondary energy source, can be generated from the conversion of other sources of energy, such as coal, natural gas, oil, nuclear power and renewable resources. Electricity prices have a deep impact on the competitiveness of a country's industry. Some electricity losses may occur during the process of transmission and distribution from generators to consumers. Generally there are two types of losses, one is technical losses which cover transmission losses and the other is non-technical losses including distribution losses and the incidence of illegal usage. The aim of this paper is to present the electricity usage and prices and is also to focus on the electricity losses occur both technical and non-technical means. An 'electricity losses map' was produced to illustrate the electricity losses. For this purpose, a vector based Geographic Information System (GIS) software package Arc GIS 8.3 was employed to map the data. The rate of losses within the electricity provided to the national network was about 19% in Turkey. The incidence of illegal usage and hence the rate of non-technical losses could be reduced dramatically through establishing regular action. (Author)

  19. Elemental profiling of laser cladded multilayer coatings by laser induced breakdown spectroscopy and energy dispersive X-ray spectroscopy

    Science.gov (United States)

    Lednev, V. N.; Sdvizhenskii, P. A.; Filippov, M. N.; Grishin, M. Ya.; Filichkina, V. A.; Stavertiy, A. Ya.; Tretyakov, R. S.; Bunkin, A. F.; Pershin, S. M.

    2017-09-01

    Multilayer tungsten carbide wear resistant coatings were analyzed by laser induced breakdown spectroscopy (LIBS) and energy dispersive X-ray (EDX) spectroscopy. Coaxial laser cladding technique was utilized to produce tungsten carbide coating deposited on low alloy steel substrate with additional inconel 625 interlayer. EDX and LIBS techniques were used for elemental profiling of major components (Ni, W, C, Fe, etc.) in the coating. A good correlation between EDX and LIBS data was observed while LIBS provided additional information on light element distribution (carbon). A non-uniform distribution of tungsten carbide grains along coating depth was detected by both LIBS and EDX. In contrast, horizontal elemental profiling showed a uniform tungsten carbide particles distribution. Depth elemental profiling by layer-by-layer LIBS analysis was demonstrated to be an effective method for studying tungsten carbide grains distribution in wear resistant coating without any sample preparation.

  20. Revisiting the Characterization of the Losses in Piezoelectric Materials from Impedance Spectroscopy at Resonance

    Directory of Open Access Journals (Sweden)

    Amador M. González

    2016-01-01

    Full Text Available Electronic devices using the piezoelectric effect contain piezoelectric materials: often crystals, but in many cases poled ferroelectric ceramics (piezoceramics, polymers or composites. On the one hand, these materials exhibit non-negligible losses, not only dielectric, but also mechanical and piezoelectric. In this work, we made simulations of the effect of the three types of losses in piezoelectric materials on the impedance spectrum at the resonance. We analyze independently each type of loss and show the differences among them. On the other hand, electrical and electronic engineers include piezoelectric sensors in electrical circuits to build devices and need electrical models of the sensor element. Frequently, material scientists and engineers use different languages, and the characteristic material coefficients do not have a straightforward translation to those specific electrical circuit components. To connect both fields of study, we propose the use of accurate methods of characterization from impedance measurements at electromechanical resonance that lead to determination of all types of losses, as an alternative to current standards. We introduce a simplified equivalent circuit model with electrical parameters that account for piezoceramic losses needed for the modeling and design of industrial applications.

  1. Revisiting the Characterization of the Losses in Piezoelectric Materials from Impedance Spectroscopy at Resonance.

    Science.gov (United States)

    González, Amador M; García, Álvaro; Benavente-Peces, César; Pardo, Lorena

    2016-01-26

    Electronic devices using the piezoelectric effect contain piezoelectric materials: often crystals, but in many cases poled ferroelectric ceramics (piezoceramics), polymers or composites. On the one hand, these materials exhibit non-negligible losses, not only dielectric, but also mechanical and piezoelectric. In this work, we made simulations of the effect of the three types of losses in piezoelectric materials on the impedance spectrum at the resonance. We analyze independently each type of loss and show the differences among them. On the other hand, electrical and electronic engineers include piezoelectric sensors in electrical circuits to build devices and need electrical models of the sensor element. Frequently, material scientists and engineers use different languages, and the characteristic material coefficients do not have a straightforward translation to those specific electrical circuit components. To connect both fields of study, we propose the use of accurate methods of characterization from impedance measurements at electromechanical resonance that lead to determination of all types of losses, as an alternative to current standards. We introduce a simplified equivalent circuit model with electrical parameters that account for piezoceramic losses needed for the modeling and design of industrial applications.

  2. Superconducting energy gap of YB6 studied by point-contact spectroscopy

    International Nuclear Information System (INIS)

    Szabo, Pavol; Kacmarcik, Jozef; Samuely, Peter; Girovsky, Jan; Gabani, Slavomir; Flachbart, Karol; Mori, Takao

    2007-01-01

    Yttrium hexaboride has the second highest critical temperature, T c ∼ 8 K, among all borides. The presented paper deals with the experimental study of its superconducting energy gap established by the method of the point-contact spectroscopy. The temperature dependence of the energy gap and the strength of the superconducting coupling is presented

  3. Addressing student models of energy loss in quantum tunnelling

    International Nuclear Information System (INIS)

    Wittmann, Michael C; Morgan, Jeffrey T; Bao Lei

    2005-01-01

    We report on a multi-year, multi-institution study to investigate students' reasoning about energy in the context of quantum tunnelling. We use ungraded surveys, graded examination questions, individual clinical interviews and multiple-choice exams to build a picture of the types of responses that students typically give. We find that two descriptions of tunnelling through a square barrier are particularly common. Students often state that tunnelling particles lose energy while tunnelling. When sketching wavefunctions, students also show a shift in the axis of oscillation, as if the height of the axis of oscillation indicated the energy of the particle. We find inconsistencies between students' conceptual, mathematical and graphical models of quantum tunnelling. As part of a curriculum in quantum physics, we have developed instructional materials designed to help students develop a more robust and less inconsistent picture of tunnelling, and present data suggesting that we have succeeded in doing so

  4. Testing the rationality of DOE's energy price forecasts under asymmetric loss preferences

    International Nuclear Information System (INIS)

    Mamatzakis, E.; Koutsomanoli-Filippaki, A.

    2014-01-01

    This paper examines the rationality of the price forecasts for energy commodities of the United States Department of Energy's (DOE), departing from the common assumption in the literature that DOE's forecasts are based on a symmetric underlying loss function with respect to positive vs. negative forecast errors. Instead, we opt for the methodology of Elliott et al. (2005) that allows testing the joint hypothesis of an asymmetric loss function and rationality and reveals the underlying preferences of the forecaster. Results indicate the existence of asymmetries in the shape of the loss function for most energy categories with preferences leaning towards optimism. Moreover, we also examine whether there is a structural break in those preferences over the examined period, 1997–2012. - Highlights: • Examine the rationality of DOE energy forecasts. • Departing from a symmetric underlying loss function. • Asymmetries exist in most energy prices. • Preferences lean towards optimism. • Examine structural breaks in those preferences

  5. Energy flow models for the estimation of technical losses in distribution network

    International Nuclear Information System (INIS)

    Au, Mau Teng; Tan, Chin Hooi

    2013-01-01

    This paper presents energy flow models developed to estimate technical losses in distribution network. Energy flow models applied in this paper is based on input energy and peak demand of distribution network, feeder length and peak demand, transformer loading capacity, and load factor. Two case studies, an urban distribution network and a rural distribution network are used to illustrate application of the energy flow models. Results on technical losses obtained for the two distribution networks are consistent and comparable to network of similar types and characteristics. Hence, the energy flow models are suitable for practical application.

  6. Privacy-preserving smart meter control strategy including energy storage losses

    OpenAIRE

    Avula, Chinni Venkata Ramana R.; Oechtering, Tobias J.; Månsson, Daniel

    2018-01-01

    Privacy-preserving smart meter control strategies proposed in the literature so far make some ideal assumptions such as instantaneous control without delay, lossless energy storage systems etc. In this paper, we present a one-step-ahead predictive control strategy using Bayesian risk to measure and control privacy leakage with an energy storage system. The controller estimates energy state using a three-circuit energy storage model to account for steady-state energy losses. With numerical exp...

  7. Determining the band gap and mean kinetic energy of atoms from reflection electron energy loss spectra

    Energy Technology Data Exchange (ETDEWEB)

    Vos, M. [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, Australian National University, Canberra ACT (Australia); Marmitt, G. G. [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, Australian National University, Canberra ACT (Australia); Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Finkelstein, Y. [Nuclear Research Center — Negev, Beer-Sheva 84190 (Israel); Moreh, R. [Physics Department, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel)

    2015-09-14

    Reflection electron energy loss spectra from some insulating materials (CaCO{sub 3}, Li{sub 2}CO{sub 3}, and SiO{sub 2}) taken at relatively high incoming electron energies (5–40 keV) are analyzed. Here, one is bulk sensitive and a well-defined onset of inelastic excitations is observed from which one can infer the value of the band gap. An estimate of the band gap was obtained by fitting the spectra with a procedure that includes the recoil shift and recoil broadening affecting these measurements. The width of the elastic peak is directly connected to the mean kinetic energy of the atom in the material (Doppler broadening). The experimentally obtained mean kinetic energies of the O, C, Li, Ca, and Si atoms are compared with the calculated ones, and good agreement is found, especially if the effect of multiple scattering is taken into account. It is demonstrated experimentally that the onset of the inelastic excitation is also affected by Doppler broadening. Aided by this understanding, we can obtain a good fit of the elastic peak and the onset of inelastic excitations. For SiO{sub 2}, good agreement is obtained with the well-established value of the band gap (8.9 eV) only if it is assumed that the intensity near the edge scales as (E − E{sub gap}){sup 1.5}. For CaCO{sub 3}, the band gap obtained here (7 eV) is about 1 eV larger than the previous experimental value, whereas the value for Li{sub 2}CO{sub 3} (7.5 eV) is the first experimental estimate.

  8. Determining the band gap and mean kinetic energy of atoms from reflection electron energy loss spectra

    International Nuclear Information System (INIS)

    Vos, M.; Marmitt, G. G.; Finkelstein, Y.; Moreh, R.

    2015-01-01

    Reflection electron energy loss spectra from some insulating materials (CaCO 3 , Li 2 CO 3 , and SiO 2 ) taken at relatively high incoming electron energies (5–40 keV) are analyzed. Here, one is bulk sensitive and a well-defined onset of inelastic excitations is observed from which one can infer the value of the band gap. An estimate of the band gap was obtained by fitting the spectra with a procedure that includes the recoil shift and recoil broadening affecting these measurements. The width of the elastic peak is directly connected to the mean kinetic energy of the atom in the material (Doppler broadening). The experimentally obtained mean kinetic energies of the O, C, Li, Ca, and Si atoms are compared with the calculated ones, and good agreement is found, especially if the effect of multiple scattering is taken into account. It is demonstrated experimentally that the onset of the inelastic excitation is also affected by Doppler broadening. Aided by this understanding, we can obtain a good fit of the elastic peak and the onset of inelastic excitations. For SiO 2 , good agreement is obtained with the well-established value of the band gap (8.9 eV) only if it is assumed that the intensity near the edge scales as (E − E gap ) 1.5 . For CaCO 3 , the band gap obtained here (7 eV) is about 1 eV larger than the previous experimental value, whereas the value for Li 2 CO 3 (7.5 eV) is the first experimental estimate

  9. Tackling Energy Loss for High-Efficiency Organic Solar Cells with Integrated Multiple Strategies.

    Science.gov (United States)

    Zuo, Lijian; Shi, Xueliang; Jo, Sae Byeok; Liu, Yun; Lin, Fracis; Jen, Alex K-Y

    2018-04-01

    Limited by the various inherent energy losses from multiple channels, organic solar cells show inferior device performance compared to traditional inorganic photovoltaic techniques, such as silicon and CuInGaSe. To alleviate these fundamental limitations, an integrated multiple strategy is implemented including molecular design, interfacial engineering, optical manipulation, and tandem device construction into one cell. Considering the close correlation among these loss channels, a sophisticated quantification of energy-loss reduction is tracked along with each strategy in a perspective to reach rational overall optimum. A novel nonfullerene acceptor, 6TBA, is synthesized to resolve the thermalization and V OC loss, and another small bandgap nonfullerene acceptor, 4TIC, is used in the back sub-cell to alleviate transmission loss. Tandem architecture design significantly reduces the light absorption loss, and compensates carrier dynamics and thermalization loss. Interfacial engineering further reduces energy loss from carrier dynamics in the tandem architecture. As a result of this concerted effort, a very high power conversion efficiency (13.20%) is obtained. A detailed quantitative analysis on the energy losses confirms that the improved device performance stems from these multiple strategies. The results provide a rational way to explore the ultimate device performance through molecular design and device engineering. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. The cascade probabilistic functions with taking into account energy losses for ions. Chapter 3

    International Nuclear Information System (INIS)

    2003-01-01

    In the Chapter 3 the cascade probabilistic functions mathematical simulation with taking into account energy losses for ions are considered. The calculation of the CPF on the computer is carried out. The influence of both the interaction number and the penetration depth on the CPF determination field for ions are revealed. The estimation of energy losses contribution in the simplest CPF is made. Calculation algorithm for radiation defects concentration at ion irradiation with use of the CPF with taking into account of energy losses is given

  11. The role of energy losses in photosynthetic light harvesting

    NARCIS (Netherlands)

    Kruger, T. P. J.; van Grondelle, R.

    2017-01-01

    Photosynthesis operates at the bottom of the food chain to convert the energy of light into carbohydrates at a remarkable global rate of about 130 TW. Nonetheless, the overall photosynthetic process has a conversion efficiency of a few percent at best, significantly less than bottom-up photovoltaic

  12. Energy and Economic Losses Due to Constant Power Outages in ...

    African Journals Online (AJOL)

    This study assesses the economic implication of electricity self-generation in Nigeria. In this regard, energy and exergetic utilization efficiencies of 19 representative generators and gas turbines from Afam power station were assessed based on real data obtained through survey of companies, oral interview, individuals and ...

  13. The energy-deposition model. Electron loss of heavy ions in collisions with neutral atoms at low and intermediate energies

    International Nuclear Information System (INIS)

    Shevelko, V.P.; Litsarev, M.S.; Kato, D.; Tawara, H.

    2010-09-01

    Single- and multiple-electron loss processes in collisions of heavy many-electron ions (positive and negative) in collisions with neutral atoms at low and intermediate energies are considered using the energy-deposition model. The DEPOSIT computer code, created earlier to calculate electron-loss cross sections at high projectile energies, is extended for low and intermediate energies. A description of a new version of DEPOSIT code is given, and the limits of validity for collision velocity in the model are discussed. Calculated electron-loss cross sections for heavy ions and atoms (N + , Ar + , Xe + , U + , U 28+ , W, W + , Ge - , Au - ), colliding with neutral atoms (He, Ne, Ar, W) are compared with available experimental and theoretical data at energies E > 10 keV/u. It is found that in most cases the agreement between experimental data and the present model is within a factor of 2. Combining results obtained by the DEPOSIT code at low and intermediate energies with those by the LOSS-R code at high energies (relativistic Born approximation), recommended electron-loss cross sections in a wide range of collision energy are presented. (author)

  14. Measurement of Quark Energy Loss in Cold Nuclear Matter at Fermilab E906/SeaQuest

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Po-Ju [Univ. of Colorado, Boulder, CO (United States)

    2017-01-01

    Parton energy loss is a process within QCD that draws considerable interest. The measurement of parton energy loss can provide valuable information for other hard-scattering processes in nuclei, and also serves as an important tool for exploring the properties of the quark-gluon plasma (QGP). Quantifying the energy loss in cold nuclear matter will help to set a baseline relative to energy loss in the QGP. With the Drell-Yan process, the energy loss of incoming quarks in cold nuclear matter can be ideally investigated since the final state interaction is expected to be minimal. E906/SeaQuest is a fixed-target experiment using the 120 GeV proton beam from the Fermilab Main Injector and has been collecting data from p+p, p+d, p+C, p+Fe, and p+W collisions. Within the E906 kinematic coverage of Drell-Yan production via the dimuon channel, the quark energy loss can be measured in a regime where other nuclear effects are expected to be small. In this thesis, the study of quark ener gy loss from different cold nuclear targets is presented.

  15. Case Library Construction Technology of Energy Loss in Distribution Networks Considering Regional Differentiation Theory

    Directory of Open Access Journals (Sweden)

    Ze Yuan

    2017-11-01

    Full Text Available The grid structures, load levels, and running states of distribution networks in different supply regions are known as the influencing factors of energy loss. In this paper, the case library of energy loss is constructed to differentiate the crucial factors of energy loss in the different supply regions. First of all, the characteristic state values are selected as the representation of the cases based on the analysis of energy loss under various voltage classes and in different types of regions. Then, the methods of Grey Relational Analysis and the K-Nearest Neighbor are utilized to implement the critical technologies of case library construction, including case representation, processing, analysis, and retrieval. Moreover, the analysis software of the case library is designed based on the case library construction technology. Some case studies show that there are many differences and similarities concerning the factors that influence the energy loss in different types of regions. In addition, the most relevant sample case can be retrieved from the case library. Compared with the traditional techniques, constructing a case library provides a new way to find out the characteristics of energy loss in different supply regions and constitutes differentiated loss-reducing programs.

  16. Program NICOLET to integrate energy loss in superconducting coils

    International Nuclear Information System (INIS)

    Vogel, H.F.

    1978-08-01

    A voltage pickup coil, inductively coupled to the magnetic field of the superconducting coil under test, is connected so its output may be compared with the terminal voltage of the coil under test. The integrated voltage difference is indicative of the resistive volt-seconds. When multiplied with the main coil current, the volt-seconds yield the loss. In other words, a hysteresis loop is obtained if the integrated voltage difference phi = ∫ΔVdt is plotted as a function of the coil current, i. First, time functions of the two signals phi(t) and i(t) are recorded on a dual-trace digital oscilloscope, and these signals are then recorded on magnetic tape. On a CDC-6600, the recorded information is decoded and plotted, and the hysteresis loops are integrated by the set of FORTRAN programs NICOLET described in this report. 4 figures

  17. Nonlinear energy loss of highly charged heavy ions

    International Nuclear Information System (INIS)

    Zwicknagel, G.Guenter.

    2000-01-01

    For slow, highly charged heavy ions strong coupling effects in the energy transfer from the projectile-ion to an electron target plasma become important. A theoretical description of this nonlinear ion stopping has to go beyond the standard approaches like the dielectric linear response or the binary collision model which are strictly valid only at weak ion-target coupling. Here we outline an improved treatment which is based on a suitable combination of binary collision and linear response contributions. As has been verified for isotropic, nonmagnetized electron plasmas by comparison with simulations, this approach well reproduces the essential features of nonlinear stopping up to moderate coupling strength. Its extension to anisotropic, magnetized electron plasmas basically involves the fully numerical determination of the momentum and energy transfer in binary ion-electron collisions in the presence of a magnetic field. First results of such calculations are presented and discussed

  18. Limits for Recombination in a Low Energy Loss Organic Heterojunction

    KAUST Repository

    Menke, S. Matthew; Sadhanala, Aditya; Nikolka, Mark; Ran, Niva A.; Ravva, Mahesh Kumar; Abdel-Azeim, Safwat; Stern, Hannah L.; Wang, Ming; Sirringhaus, Henning; Nguyen, Thuc-Quyen; Bredas, Jean-Luc; Bazan, Guillermo C.; Friend, Richard H.

    2016-01-01

    Donor-acceptor organic solar cells often show high quantum yields for charge collection, but relatively low open-circuit voltages (VOC) limit power conversion efficiencies to around 12%. We report here the behavior of a system, PIPCP:PC61BM, that exhibits very low electronic disorder (Urbach energy less than 27 meV), very high carrier mobilities in the blend (field-effect mobility for holes >10-2 cm2 V-1 s-1), and a very low driving energy for initial charge separation (50 meV). These characteristics should give excellent performance, and indeed, the VOC is high relative to the donor energy gap. However, we find the overall performance is limited by recombination, with formation of lower-lying triplet excitons on the donor accounting for 90% of the recombination. We find this is a bimolecular process that happens on time scales as short as 100 ps. Thus, although the absence of disorder and the associated high carrier mobility speeds up charge diffusion and extraction at the electrodes, which we measure as early as 1 ns, this also speeds up the recombination channel, giving overall a modest quantum yield of around 60%. We discuss strategies to remove the triplet exciton recombination channel.

  19. Limits for Recombination in a Low Energy Loss Organic Heterojunction

    KAUST Repository

    Menke, S. Matthew

    2016-11-03

    Donor-acceptor organic solar cells often show high quantum yields for charge collection, but relatively low open-circuit voltages (VOC) limit power conversion efficiencies to around 12%. We report here the behavior of a system, PIPCP:PC61BM, that exhibits very low electronic disorder (Urbach energy less than 27 meV), very high carrier mobilities in the blend (field-effect mobility for holes >10-2 cm2 V-1 s-1), and a very low driving energy for initial charge separation (50 meV). These characteristics should give excellent performance, and indeed, the VOC is high relative to the donor energy gap. However, we find the overall performance is limited by recombination, with formation of lower-lying triplet excitons on the donor accounting for 90% of the recombination. We find this is a bimolecular process that happens on time scales as short as 100 ps. Thus, although the absence of disorder and the associated high carrier mobility speeds up charge diffusion and extraction at the electrodes, which we measure as early as 1 ns, this also speeds up the recombination channel, giving overall a modest quantum yield of around 60%. We discuss strategies to remove the triplet exciton recombination channel.

  20. Energy loss of particles in dense matter - calorimetry

    International Nuclear Information System (INIS)

    Wigmans, R.

    1987-08-01

    In the last decade, a class of detectors gradually have become more and more important in experimental particle physics. They are called calorimeters, or total absorption detectors. Basically a calorimeter is a block of matter, in which the particle to be measured interacts, and deposits all its energy in the form of a shower of decreasingly lower-energy particles. The block is made such that certain (usually small and hopefully constant) fraction of the initial particle energy is transformed in a measurable signal (light, electrical charge). This lecture mainly deals with sampling calorimeters but in section 2 also fully sensitive devices are briefly treated. In this section calorimeters for detecting electromagnetic showers are discussed. The physics processes relevant to em shower development are examined, and the factors that limit the performance of em calorimeters. Section 3 is devoted to readout techniques for sampling calorimeters. In sections 4-7 hadron calorimeters are discussed. The physics processes relevant to hadron shower development, their consequences for the calorimeter signals and the possibility for optimizing the performance of hadron calorimeters are examined. In section 8 an outlook for future development is given. 31 refs.; 48 figs

  1. Modern developments in energy, combustion and spectroscopy in honor of S. S. Penner

    CERN Document Server

    Lapp, M; Williams, F A; Oppenheim, A K; Williams, F A

    2013-01-01

    This compendium of technical articles is dedicated to Professor Stanford Solomon Penner on the occasion of his 70th birthday. As one of the most prominent scientists of our times, he has been particularly instrumental in advancing the field of combustion science while simultaneously he has developed quantitative spectroscopy into an important engineering discipline, and is also a leading international expert on energy issues. Written primarily by researchers who were Professor Penner's doctorate students during the last four decades, the articles consist of original contributions as well as previously published papers that provide important insights into combustion, spectroscopy, and energy problems. Among the topics included are turbulent combustion, flame structure, detonations, spectroscopic diagnostics, spectroscopy of atmospheric gases, and physical problems associated with nuclear reactors as well as electric power distribution, and energy conversion. The book includes a short biography of Professor Pen...

  2. Bremsstrahlung spectra from thick-target electron beams with noncollisional energy losses

    International Nuclear Information System (INIS)

    Brown, J.C.; MacKinnon, A.L.

    1985-01-01

    We consider what can be learned from the bremsstrahlung radiation of fast electrons in a thick target, generalized to include electron energy losses additional to collisions. We show that the observed photon spectrum can, in principle, be inverted to yield an integral functional of the electron spectrum and the effective energy loss rate. In the light of this result, there seems no reason to suppose, in the absence of a priori information to the contrary, that the photon spectrum is symptomatic more of the fast electron distribution than of the energy loss processes. In cases where the electron injection spectrum is known on independent observational or theoretical grounds, it is possible to infer an effective, ''phenomenological'' energy loss function. In the more general case, however, fullest possible modeling of the physical situation and comparison of the resulting spectrum with observations is all that can be attempted

  3. Control of Refrigeration Systems for Trade-off between Energy Consumption and Food Quality Loss

    DEFF Research Database (Denmark)

    Cai, Junping

    In supermarkets, control strategies determine both the energy consumption of refrigeration systems and the quality loss of refrigerated foodstuffs. The question is, what can be done to optimize the balance between quality loss and energy consumption? This thesis tries to answer this question...... by applying two main optimization strategies to traditional refrigeration systems. The first strategy is a new defrost-on-demand scheme, which based on an objective function between quality loss and energy consumption, continuously seeks an optimal time interval for defrosting in dynamic situation. The second...... strategy is through utilization of the thermal mass of the refrigerated foodstuffs, the day-night temperature variation and the capacity control of the compressor, to realize a trade-off between system energy consumption and food quality loss....

  4. Characteristic electron energy loss in lanthanum films adsorbed on tungsten (110) single crystal

    International Nuclear Information System (INIS)

    Gorodetskij, D.A.; Gorchinskij, A.D.; Kobylyanskij, A.V.

    1988-01-01

    The spectrum of electron energy loss (ELS) in a wide range of energy loss 0-150 eV has been studied for La films adsorbed on W(110) single crystal with the coverage Θ from submonolayer to a few monolayers. The concentration dependence of loss energy peaks amplitude of different nature has been studied for the adsorption of rare earth element on refractory substrate. It has been shown that the essential information for the interpretation of the energy loss nature may be obtained by the investigation of such dependences for La adsorption on W(110). It is found that the surface and bulk plasmons peaks appear in ELS of La-W(110) system before the completion of the physical monolayer. Thus, the collectivization of valence electrons in the rare earth element film at the transition metal surface ensues for the submonolayer coverage like in the case of collective processes in alkali and alkaline earth element films

  5. An investigation of standby energy losses in residential sector: Solutions and policies

    Energy Technology Data Exchange (ETDEWEB)

    Singh Solanki, Parmal [Caledonian (University) College of Engineering, Muscat (Oman); Sarma Mallela, Venkateswara [G. Narayanamma Institute of Technology and Science (for Women), Hyderabad (India); Zhou, Chengke [Glasgow Caledonian University, Glasgow, Scotland (United Kingdom)

    2013-07-01

    This paper investigates the standby power losses of household appliances and determines these losses by field measurements and bottom-up approaches. It is revealed that average standby power losses of e-appliances at household in Oman is 103.4 Watts and could further increase if other miscellaneous appliances are also taken into account. Calculations show that TV sets alone are responsible to consume 1.89 MW standby powers across the country. The paper considers various technological and socio-economic options to diminish the standby power consumption and signify that 42.72% of energy consumed by appliances can be saved by end-users implementing suitable measures. Energy management programmes like energy efficiency standards, labelling and policy instruments to tackle the standby power losses are also discussed. Finally, paper looks into the barriers and their way-outs to implement the energy efficiency standards and labelling.

  6. Understanding energy loss in parallelly connected microbial fuel cells: Non-Faradaic current.

    Science.gov (United States)

    An, Junyeong; Sim, Junyoung; Feng, Yujie; Lee, Hyung-Sool

    2016-03-01

    In this work, the mechanisms of energy loss in parallel connection of microbial fuel cells (MFCs) is explored using two MFC units producing different open circuit voltage (OCV) and current. In open circuit mode, non-Faradaic current flows in low OCV unit, implying energy loss caused by different OCVs in parallelly stacked MFCs. In a stacked MFC in parallel under close circuit mode, it is confirmed that energy loss occurs until the working voltage in high OCV unit becomes identical to the other unit having low OCV. This result indicates that different voltage between individual MFC units can cause energy loss due to both non-Faradic and Faradaic current that flow from high voltage unit to low voltage unit even in parallelly stacked MFCs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Incorporation of Finite Element Analysis into Annual Energy Loss Estimation for Permanent Magnet Wind Turbine Generators

    DEFF Research Database (Denmark)

    Henriksen, Matthew Lee; Jensen, Bogi Bech

    2013-01-01

    Several methods of estimating the annual energy losses for wind turbine generators are investigated in this paper. Utilizing a high amount of transient simulations with motion is first demonstrated. Usage of a space-time transformation for prediction of iron losses is also explored. The methods, ...

  8. The sub-bandgap energy loss satellites in the RIXS spectra of beryllium compounds

    International Nuclear Information System (INIS)

    Kuusik, I.; Kaeaembre, T.; Kooser, K.; Pustovarov, V.; Ivanov, V.; Kukk, E.; Kikas, A.

    2011-01-01

    Research highlights: → Be 1s RIXS spectra have been measured in Be containing crystals phenakite and chrysoberyl. → A strong energy loss sideband to the elastic scattering peak similar to BeO is found in both minerals. → Additionally the Si 2p RIXS spectra of phenakite also show a strong energy loss sideband to the elastic scattering peak. → The energy loss shoulder appears to result from lattice relaxation in the absorption site. - Abstract: Resonant X-ray inelastic scattering spectra have been measured in BeO, phenakite (Be 2 SiO 4 ) and chrysoberyl (BeAl 2 O 4 ) with the excitation energy near the beryllium K edge. The RIXS spectra excited in the vicinity of the Be 1s core resonance show two principal features: the scattering on a valence excitation (which at higher excitation energies verges into the characteristic K α emission), and a remarkably strong energy loss sideband to the elastic scattering peak. The energy loss shoulder appears to result from lattice relaxation in the absorption site. The comparison of the RIXS spectra of phenakite, chrysoberyl and BeO shows that the strength of the low energy sideband differs greatly; it is strongest in BeO and weakest in phenakite. The Si 2p RIXS spectra of phenakite also display a similar strong sub-bandgap energy loss tail. To gain further insight to this process, transitions in a system with a single vibrational mode have been modelled. The phonon relaxation has been simulated empirically by 'smearing' the photoabsortion-populated vibrational levels with lower levels. This simple model is able to qualitatively explain this wide energy loss shoulder.

  9. The sub-bandgap energy loss satellites in the RIXS spectra of beryllium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kuusik, I., E-mail: ivar@fi.tartu.ee [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu (Estonia); Kaeaembre, T. [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu (Estonia); Kooser, K. [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu (Estonia); Department of Physics and Astronomy, University of Turku, Turku (Finland); Pustovarov, V.; Ivanov, V. [Ural State Technical University-UPI, Yekaterinburg (Russian Federation); Kukk, E. [Department of Physics and Astronomy, University of Turku, Turku (Finland); Kikas, A. [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu (Estonia)

    2011-07-15

    Research highlights: {yields} Be 1s RIXS spectra have been measured in Be containing crystals phenakite and chrysoberyl. {yields} A strong energy loss sideband to the elastic scattering peak similar to BeO is found in both minerals. {yields} Additionally the Si 2p RIXS spectra of phenakite also show a strong energy loss sideband to the elastic scattering peak. {yields} The energy loss shoulder appears to result from lattice relaxation in the absorption site. - Abstract: Resonant X-ray inelastic scattering spectra have been measured in BeO, phenakite (Be{sub 2}SiO{sub 4}) and chrysoberyl (BeAl{sub 2}O{sub 4}) with the excitation energy near the beryllium K edge. The RIXS spectra excited in the vicinity of the Be 1s core resonance show two principal features: the scattering on a valence excitation (which at higher excitation energies verges into the characteristic K{sub {alpha}} emission), and a remarkably strong energy loss sideband to the elastic scattering peak. The energy loss shoulder appears to result from lattice relaxation in the absorption site. The comparison of the RIXS spectra of phenakite, chrysoberyl and BeO shows that the strength of the low energy sideband differs greatly; it is strongest in BeO and weakest in phenakite. The Si 2p RIXS spectra of phenakite also display a similar strong sub-bandgap energy loss tail. To gain further insight to this process, transitions in a system with a single vibrational mode have been modelled. The phonon relaxation has been simulated empirically by 'smearing' the photoabsortion-populated vibrational levels with lower levels. This simple model is able to qualitatively explain this wide energy loss shoulder.

  10. Hydrodynamic evolution and jet energy loss in Cu + Cu collisions

    International Nuclear Information System (INIS)

    Schenke, Bjoern; Jeon, Sangyong; Gale, Charles

    2011-01-01

    We present results from a hybrid description of Cu + Cu collisions using (3 + 1)-dimensional hydrodynamics (music) for the bulk evolution and a Monte Carlo simulation (martini) for the evolution of high-momentum partons in the hydrodynamical background. We explore the limits of this description by going to small system sizes and determine the dependence on different fractions of wounded nucleon and binary collisions scaling of the initial energy density. We find that Cu + Cu collisions are well described by the hybrid description at least up to 20% central collisions.

  11. Energy losses in mixed matrix superconducting wires under fast pulsed conditions

    International Nuclear Information System (INIS)

    Wollan, J.J.

    1976-01-01

    Energy losses have been measured on a set of mixed matrix (CuNi, Cu, NbTi) superconducting wires at B's up to 1.5 x 10 7 G/s. The losses have been measured as a function of wire diameter, twist pitch, maximum applied field, and B. Both static and dynamic losses were measured for a field applied perpendicularly to the wire axis. The dynamic losses were measured by slowly applying an external field to a sample and then causing the field to decay exponentially in roughly 1 ms to 10 ms. Under low B (9 kG) and B (10 6 G/s) conditions the hysteretic loss dominated. At high B (21 kG) and B (1.5 x 10 7 G/s) the matrix losses became dominant. The systematic variation of the losses with the mentioned parameters will be presented and will be compared to theoretical predictions

  12. High Energy Electron Dosimetry by Alanine/ESR Spectroscopy

    International Nuclear Information System (INIS)

    Chu, Sung Sil

    1989-01-01

    Dosimetry based on electron spin resonance(ESR) analysis of radiation induced free radicals in amino acids is relevant to biological dosimetry applications. Alanine detectors are without walls and are tissue equivalent. Therefore, alanine ESR dosimetry looks promising for use in the therapy level. The dose range of the alanine/ESR dosimetry system can be extended down to l Gy. In a water phantom the absorbed dose of electrons generated by a medical linear accelerator of different initial energies (6-21 MeV) and therapeutic dose levels(1-60 Gy) was measured. Furthermore, depth dose measurements carried out with alanine dosimeters were compared with ionization chamber measurements. As the results, the measured absorbed doses for shallow depth of initial electron energies above 15 MeV were higher by 2-5% than those calculated by nominal energy CE factors. This seems to be caused by low energy scattered beams generated from the scattering foil and electron cones of beam projecting device in medical linear accelerator

  13. TFAP2B influences the effect of dietary fat on weight loss under energy restriction

    DEFF Research Database (Denmark)

    Stocks, Tanja; Angquist, Lars; Banasik, Karina

    2012-01-01

    Numerous gene loci are related to single measures of body weight and shape. We investigated if 55 SNPs previously associated with BMI or waist measures, modify the effects of fat intake on weight loss and waist reduction under energy restriction.......Numerous gene loci are related to single measures of body weight and shape. We investigated if 55 SNPs previously associated with BMI or waist measures, modify the effects of fat intake on weight loss and waist reduction under energy restriction....

  14. Energy loss of ions by electric-field fluctuations in a magnetized plasma.

    Science.gov (United States)

    Nersisyan, Hrachya B; Deutsch, Claude

    2011-06-01

    The results of a theoretical investigation of the energy loss of charged particles in a magnetized classical plasma due to the electric-field fluctuations are reported. The energy loss for a test particle is calculated through the linear-response theory. At vanishing magnetic field, the electric-field fluctuations lead to an energy gain of the charged particle for all velocities. It has been shown that in the presence of strong magnetic field, this effect occurs only at low velocities. In the case of high velocities, the test particle systematically loses its energy due to the interaction with a stochastic electric field. The net effect of the fluctuations is the systematic reduction of the total energy loss (i.e., the sum of the polarization and stochastic energy losses) at vanishing magnetic field and reduction or enhancement at strong field, depending on the velocity of the particle. It is found that the energy loss of the slow heavy ion contains an anomalous term that depends logarithmically on the projectile mass. The physical origin of this anomalous term is the coupling between the cyclotron motion of the plasma electrons and the long-wavelength, low-frequency fluctuations produced by the projectile ion. This effect may strongly enhance the stochastic energy gain of the particle.

  15. Reducing heat loss from the energy absorber of a solar collector

    Science.gov (United States)

    Chao, Bei Tse; Rabl, Ari

    1976-01-01

    A device is provided for reducing convective heat loss in a cylindrical radiant energy collector. It includes a curved reflective wall in the shape of the arc of a circle positioned on the opposite side of the exit aperture from the reflective side walls of the collector. Radiant energy exiting the exit aperture is directed by the curved wall onto an energy absorber such that the portion of the absorber upon which the energy is directed faces downward to reduce convective heat loss from the absorber.

  16. High energy photoelectron spectroscopy in basic and applied science: Bulk and interface electronic structure

    Energy Technology Data Exchange (ETDEWEB)

    Knut, Ronny; Lindblad, Rebecka [Department of Physics and Astronomy, Uppsala University, SE-751 21 Uppsala (Sweden); Gorgoi, Mihaela [Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Rensmo, Håkan [Department of Physics and Astronomy, Uppsala University, SE-751 21 Uppsala (Sweden); Karis, Olof, E-mail: olof.karis@physics.uu.se [Department of Physics and Astronomy, Uppsala University, SE-751 21 Uppsala (Sweden)

    2013-10-15

    Highlights: •We demonstrate how hard X-ray photoelectron spectroscopy can be used to investigate interface properties of multilayers. •By combining HAXPES and statistical methods we are able to provide quantitative analysis of the interface diffusion process. •We show how photoionization cross sections can be used to map partial density of states contributions to valence states. •We use HAXPES to provide insight into the valence electronic structure of e.g. multiferroics and dye-sensitized solar cells. -- Abstract: With the access of new high-performance electron spectrometers capable of analyzing electron energies up to the order of 10 keV, the interest for photoelectron spectroscopy has grown and many new applications of the technique in areas where electron spectroscopies were considered to have limited use have been demonstrated over the last few decades. The technique, often denoted hard X-ray photoelectron spectroscopy (HX-PES or HAXPES), to distinguish the experiment from X-ray photoelectron spectroscopy performed at lower energies, has resulted in an increasing interest in photoelectron spectroscopy in many areas. The much increased mean free path at higher kinetic energies, in combination with the elemental selectivity of the core level spectroscopies in general has led to this fact. It is thus now possible to investigate the electronic structure of materials with a substantially enhanced bulk sensitivity. In this review we provide examples from our own research using HAXPES which to date has been performed mainly at the HIKE facility at the KMC-1 beamline at HZB, Berlin. The review exemplifies the new opportunities using HAXPES to address both bulk and interface electronic properties in systems relevant for applications in magnetic storage, energy related research, but also in purely curiosity driven problems.

  17. High energy photoelectron spectroscopy in basic and applied science: Bulk and interface electronic structure

    International Nuclear Information System (INIS)

    Knut, Ronny; Lindblad, Rebecka; Gorgoi, Mihaela; Rensmo, Håkan; Karis, Olof

    2013-01-01

    Highlights: •We demonstrate how hard X-ray photoelectron spectroscopy can be used to investigate interface properties of multilayers. •By combining HAXPES and statistical methods we are able to provide quantitative analysis of the interface diffusion process. •We show how photoionization cross sections can be used to map partial density of states contributions to valence states. •We use HAXPES to provide insight into the valence electronic structure of e.g. multiferroics and dye-sensitized solar cells. -- Abstract: With the access of new high-performance electron spectrometers capable of analyzing electron energies up to the order of 10 keV, the interest for photoelectron spectroscopy has grown and many new applications of the technique in areas where electron spectroscopies were considered to have limited use have been demonstrated over the last few decades. The technique, often denoted hard X-ray photoelectron spectroscopy (HX-PES or HAXPES), to distinguish the experiment from X-ray photoelectron spectroscopy performed at lower energies, has resulted in an increasing interest in photoelectron spectroscopy in many areas. The much increased mean free path at higher kinetic energies, in combination with the elemental selectivity of the core level spectroscopies in general has led to this fact. It is thus now possible to investigate the electronic structure of materials with a substantially enhanced bulk sensitivity. In this review we provide examples from our own research using HAXPES which to date has been performed mainly at the HIKE facility at the KMC-1 beamline at HZB, Berlin. The review exemplifies the new opportunities using HAXPES to address both bulk and interface electronic properties in systems relevant for applications in magnetic storage, energy related research, but also in purely curiosity driven problems

  18. Direct observation of multistep energy transfer in LHCII with fifth-order 3D electronic spectroscopy.

    Science.gov (United States)

    Zhang, Zhengyang; Lambrev, Petar H; Wells, Kym L; Garab, Győző; Tan, Howe-Siang

    2015-07-31

    During photosynthesis, sunlight is efficiently captured by light-harvesting complexes, and the excitation energy is then funneled towards the reaction centre. These photosynthetic excitation energy transfer (EET) pathways are complex and proceed in a multistep fashion. Ultrafast two-dimensional electronic spectroscopy (2DES) is an important tool to study EET processes in photosynthetic complexes. However, the multistep EET processes can only be indirectly inferred by correlating different cross peaks from a series of 2DES spectra. Here we directly observe multistep EET processes in LHCII using ultrafast fifth-order three-dimensional electronic spectroscopy (3DES). We measure cross peaks in 3DES spectra of LHCII that directly indicate energy transfer from excitons in the chlorophyll b (Chl b) manifold to the low-energy level chlorophyll a (Chl a) via mid-level Chl a energy states. This new spectroscopic technique allows scientists to move a step towards mapping the complete complex EET processes in photosynthetic systems.

  19. Optimized Free Energies from Bidirectional Single-Molecule Force Spectroscopy

    Science.gov (United States)

    Minh, David D. L.; Adib, Artur B.

    2008-05-01

    An optimized method for estimating path-ensemble averages using data from processes driven in opposite directions is presented. Based on this estimator, bidirectional expressions for reconstructing free energies and potentials of mean force from single-molecule force spectroscopy—valid for biasing potentials of arbitrary stiffness—are developed. Numerical simulations on a model potential indicate that these methods perform better than unidirectional strategies.

  20. Gain and loss mechanisms for neutral species in low pressure fluorocarbon plasmas by infrared spectroscopy

    International Nuclear Information System (INIS)

    Nelson, Caleb T.; Overzet, Lawrence J.; Goeckner, Matthew J.

    2012-01-01

    This article examines the chemical reaction pathways of stable neutral species in fluorocarbon plasmas. Octafluorocyclobutane (c-C 4 F 8 ) inductively coupled plasma discharges were found to primarily produce stable and metastable products downstream from the discharge, including c-C 4 F 8 , C 2 F 4 , C 2 F 6 , CF 4 , C 3 F 8 , C 4 F 10 , C 3 F 6 , and CF 2 . A novel analysis technique allows the estimation of gain and loss rates for neutral species in the steady state as functions of residence time, pressure, and discharge power. The gain and loss rates show that CF 4 , C 2 F 6 , C 3 F 8 , and C 4 F 10 share related gain mechanisms, speculated to occur at the surface. Further analysis confirms that CF 2 is predominantly produced at the chamber walls through electron impact dissociation of C 2 F 4 and lost through gas-phase addition reactions to form C 2 F 4 . Additionally, time-resolved FTIR spectra provide a second-order rate coefficient of 1.8 × 10 −14 cm 3 /s for the gas-phase addition of CF 2 to form C 2 F 4 . Finally, C 2 F 4, which is much more abundant than CF 2 in the discharge, is shown to be dominantly produced through electron impact dissociation of c-C 4 F 8 and lost through either surface or gas-phase addition reactions.

  1. Energy loss and straggling of MeV Si ions in gases

    Energy Technology Data Exchange (ETDEWEB)

    Vockenhuber, C., E-mail: vockenhuber@phys.ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Arstila, K. [Department of Physics, University of Jyväskylä, 40014 Jyväskylä (Finland); Jensen, J. [Department of Physics, Chemistry and Biology, Linköping University, 581 83 Linköping (Sweden); Julin, J.; Kettunen, H.; Laitinen, M.; Rossi, M.; Sajavaara, T. [Department of Physics, University of Jyväskylä, 40014 Jyväskylä (Finland); Thöni, M. [Laboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Whitlow, H.J. [Institut des Microtechnologies Appliquées Arc, Haute Ecole Arc Ingénierie, 2300 La Chaux-de-Fonds (Switzerland)

    2017-01-15

    We present measurements of energy loss and straggling of Si ions in gases. An energy range from 0.5 to 12 MeV/u was covered using the 6 MV EN tandem accelerator at ETH Zurich, Switzerland, and the K130 cyclotron accelerator facility at the University of Jyväskylä, Finland. Our energy-loss data compare well with calculation based on the SRIM and PASS code. The new straggling measurements support a pronounced peak in He gas at around 4 MeV/u predicted by recent theoretical calculations. The straggling curve structure in the other gases (N{sub 2}, Ne, Ar, Kr) is relatively flat in the covered energy range. Although there is a general agreement between the straggling data and the theoretical calculations, the experimental uncertainties are too large to confirm or exclude the predicted weak multi-peak structure in the energy-loss straggling.

  2. Electron loss from multiply protonated lysozyme ions in high energy collisions with molecular oxygen

    DEFF Research Database (Denmark)

    Hvelplund, P; Nielsen, SB; Sørensen, M

    2001-01-01

    We report on the electron loss from multiply protonated lysozyme ions Lys-Hn(n)+ (n = 7 - 17) and the concomitant formation of Lys-Hn(n+1)+. in high-energy collisions with molecular oxygen (laboratory kinetic energy = 50 x n keV). The cross section for electron loss increases with the charge state...... of the precursor from n = 7 to n = 11 and then remains constant when n increases further. The absolute size of the cross section ranges from 100 to 200 A2. The electron loss is modeled as an electron transfer process between lysozyme cations and molecular oxygen....

  3. Pore size determination from charged particle energy loss measurement

    International Nuclear Information System (INIS)

    Brady, F.P.; Armitage, B.H.

    1977-01-01

    A new method aimed at measuring porosity and mean pore size in materials has been developed at Harwell. The energy width or variance of a transmitted or backscattered charged particle beam is measured and related to the mean pore size via the assumption that the variance in total path length in the porous material is given by (Δx 2 )=na 2 , where n is the mean number of pores and a the mean pore size. It is shown on the basis of a general and rigorous theory of total path length distribution that this approximation can give rise to large errors in the mean pore size determination particularly in the case of large porosities (epsilon>0.5). In practice it is found that it is not easy to utilize fully the general theory because accurate measurements of the first four moments are required to determine the means and variances of the pore and inter-pore length distributions. Several models for these distributions are proposed. When these are incorporated in the general theory the determinations of mean pore size from experimental measurements on powder samples are in good agreement with values determined by other methods. (Auth.)

  4. (e,2e) spectroscopy of solids with improved energy resolution

    International Nuclear Information System (INIS)

    Canney, S.; Brunger, M.J.; Storer, P.J.; Utteridge, S.; Vos, M.; Weigold, E.

    1996-03-01

    A brief overview of the (e,2e) technique as applied to solids is reported, including the spectrometer used in these studies. In particular it is described how the energy resolution of the spectrometer has been improved, by a factor of two, by the addition of an electron monochromator for production of the incident electron beam. This monochromator is also discussed in some detail. Results obtained using the monochromated beam are compared with previous data collected with a standard electron-gun source. 37 refs., 9 figs

  5. Surface plasmon modes of a single silver nanorod: An electron energy loss study

    DEFF Research Database (Denmark)

    Nicoletti, Olivia; Wubs, Martijn; Mortensen, N. Asger

    2011-01-01

    We present an electron energy loss study using energy filtered TEM of spatially resolved surface plasmon excitations on a silver nanorod of aspect ratio 14.2 resting on a 30 nm thick silicon nitride membrane. Our results show that the excitation is quantized as resonant modes whose intensity maxima...

  6. Soil fertility and soil loss constraints on crop residue removal for energy production

    Energy Technology Data Exchange (ETDEWEB)

    Flaim, S.

    1979-07-01

    A summary of the methodologies used to estimate the soil fertility and soil loss constraints on crop residue removal for energy production is presented. Estimates of excess residue are developed for wheat in north-central Oklahoma and for corn and soybeans in central Iowa. These sample farming situations are analyzed in other research in the Analysis Division of the Solar Energy Research Institute.

  7. CMB bounds on dark matter annihilation: Nucleon energy losses after recombination

    NARCIS (Netherlands)

    Weniger, C.; Serpico, P.D.; Iocco, F.; Bertone, G.

    2013-01-01

    We consider the propagation and energy losses of protons and antiprotons produced by dark matter annihilation at redshifts 100energy injected into e± and γ’s,

  8. Vibrational spectroscopy and intramolecular energy transfer in isocyanic acid (HNCO)

    International Nuclear Information System (INIS)

    Coffey, M.J.; Berghout, H.L.; Woods, E. III; Crim, F.F.

    1999-01-01

    Room temperature photoacoustic spectra in the region of the first through the fourth overtones (2ν 1 to 5ν 1 ) and free-jet action spectra of the second through the fourth overtones (3ν 1 to 5ν 1 ) of the N - H stretching vibration permit analysis of the vibrational and rotational structure of HNCO. The analysis identifies the strong intramolecular couplings that control the early stages of intramolecular vibrational energy redistribution (IVR) and gives the interaction matrix elements between the zero-order N - H stretching states and the other zero-order states with which they interact. The experimentally determined couplings and zero-order state separations are consistent with ab initio calculations of East, Johnson, and Allen [J. Chem. Phys. 98, 1299 (1993)], and comparison with the calculation identifies the coupled states and likely interactions. The states most strongly coupled to the pure N - H stretching zero-order states are ones with a quantum of N - H stretching excitation (ν 1 ) replaced by different combinations of N - C - O asymmetric or symmetric stretching excitation (ν 2 or ν 3 ) and trans-bending excitation (ν 4 ). The two strongest couplings of the nν 1 state are to the states (n-1)ν 1 +ν 2 +ν 4 and (n-1)ν 1 +ν 3 +2ν 4 , and sequential couplings through a series of low order resonances potentially play a role. The analysis shows that if the pure N - H stretch zero-order state were excited, energy would initially flow out of that mode into the strongly coupled mode in 100 fs to 700 fs, depending on the level of initial excitation. copyright 1999 American Institute of Physics

  9. Quark Energy Loss and Shadowing in Nuclear Drell-Yan Process

    International Nuclear Information System (INIS)

    Duan Chungui; Cui Shuwen; Yan Zhanyuan

    2005-01-01

    The energy loss effect in nuclear matter is another nuclear effect apart from the nuclear effects on the parton distribution as in deep inelastic scattering process. The quark energy loss can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of three kinds of quark energy loss parameterizations given in literature and the nuclear parton distribution extracted only with lepton-nucleus deep inelastic scattering experimental data, measured Drell-Yan production cross sections are analyzed for 800 GeV proton incident on a variety of nuclear targets from FNAL E866. It is shown that our results with considering the energy loss effect are much different from those of the FNAL E866, who analyzes the experimental data with the nuclear parton distribution functions obtained by using the deep inelastic lA collisions and pA nuclear Drell-Yan data. Considering the existence of energy loss effect in Drell-Yan lepton pairs production, we suggest that the extraction of nuclear parton distribution functions should not include Drell-Yan experimental data.

  10. Quark Energy Loss and Shadowing in Nuclear Drell-Yan Process

    Institute of Scientific and Technical Information of China (English)

    DUAN Chun-Gui; CUI Shu-Wen; YAN Zhan-Yuan

    2005-01-01

    The energy loss effect in nuclear matter is another nuclear effect apart from the nuclear effects on the parton distribution as in deep inelastic scattering process. The quark energy loss can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of three kinds of quark energy loss parameterizations given in literature and the nuclear parton distribution extracted only with lepton-nucleus deep inelastic scattering experimental data, measured Drell-Yan production cross sections are analyzed for 800 GeV proton incident on a variety of nuclear targets from FNAL E866. It is shown that our results with considering the energy loss effect are much different from those of the FNAL E866, who analyzes the experimental data with the nuclear parton distribution functions obtained by using the deep inelastic IA collisions and pA nuclear Drell-Yan data. Considering the existence of energy loss effect in Drell-Yan lepton pairs production, we suggest that the extraction of nuclear parton distribution functions should not include Drell-Yan experimental data.

  11. Multiple parton scattering in nuclei: heavy quark energy loss and modified fragmentation functions

    International Nuclear Information System (INIS)

    Zhang Benwei; Wang, Enke; Wang Xinnian

    2005-01-01

    Multiple scattering, induced radiative energy loss and modified fragmentation functions of a heavy quark in nuclear matter are studied within the framework of generalized factorization in perturbative QCD. Modified heavy quark fragmentation functions and energy loss are derived in detail with illustration of the mass dependencies of the Landau-Pomeranchuk-Migdal interference effects and heavy quark energy loss. Due to the quark mass dependence of the gluon formation time, the nuclear size dependencies of nuclear modification of the heavy quark fragmentation function and heavy quark energy loss are found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss of the heavy quark is also significantly suppressed due to limited cone of gluon radiation imposed by the mass. Medium modification of the heavy quark fragmentation functions is found to be limited to the large z region due to the form of heavy quark fragmentation functions in vacuum

  12. Deep-level transient spectroscopy of low-energy ion-irradiated silicon

    DEFF Research Database (Denmark)

    Kolkovsky, Vladimir; Privitera, V.; Nylandsted Larsen, Arne

    2009-01-01

     During electron-gun deposition of metal layers on semiconductors, the semiconductor is bombarded with low-energy metal ions creating defects in the outermost surface layer. For many years, it has been a puzzle why deep-level transient spectroscopy spectra of the as-deposited, electron-gun evapor...

  13. Distributions of energy losses of electrons and pions in the CBM TRD

    International Nuclear Information System (INIS)

    Akishina, E.P.; Akishina, T.P.; Ivanov, V.V.; Denisova, O.Yu.

    2007-01-01

    The distributions of energy losses of electrons and pions in the TRD detector of the CBM experiment are considered. We analyze the measurements of the energy deposits in one-layer TRD prototype obtained during the test beam (GSI, Darmstadt, February 2006) and Monte Carlo simulations for the n-layered TRD realized with the help of GEANT in frames of the CBM ROOT. We show that 1) energy losses both for real measurements and GEANT simulations are approximated with a high accuracy by a log-normal distribution for π and a weighted sum of two log-normal distributions for e; 2) GEANT simulations noticeably differ from real measurements and, as a result, we have a significant loss in the efficiency of the e/π identification. A procedure to control and correct the process of the energy deposit of electrons in the TRD is developed

  14. Electronic energy loss of low velocity H+ beams in Al, Ag, Sb, Au and Bi

    International Nuclear Information System (INIS)

    Valdes, J.E.; Martinez Tamayo, G.; Lantschner, G.H.; Eckardt, J.C.; Arista, N.R.

    1993-01-01

    The energy loss of H + ions in thin polycrystalline Al, Sb, Ag, Au and Bi films has been determined in the energy range below 10 keV. This low-energy range is of special interest to fill a lack of low-energy experimental data and test various theoretical predictions and semiempirical formulas. We find that the general theoretical prediction of a velocity-proportional dependence of energy loss does not hold for all targets studied in this work. The velocity-proportionality is better satisfied for Al, Sb and Bi, whereas a departure from such dependence is observed at lower energies for Ag and Au targets. The results obtained here are in good general agreement with nonlinear stopping power calculations based on density functional theory. Comparison with semiempirical predictions, and other experimental results are also done. (orig.)

  15. Reaction rate and energy-loss rate for photopair production by relativistic nuclei

    Science.gov (United States)

    Chodorowski, Michal J.; Zdziarski, Andrzej A.; Sikora, Marek

    1992-01-01

    The process of e(+/-) pair production by relativistic nuclei on ambient photons is considered. The process is important for cosmic-ray nuclei in interstellar and intergalactic space as well as in galactic and extragalactic compact objects. The rate of this process is given by an integral of the cross section over the photon angular and energy distribution. In the case of isotropic photons, the angular integration is performed to provide an expression for the rate at given photon energy in the nucleus rest frame. The total rate then becomes a single integral of that rate over the photon energy distribution. Formulas are also given for the fractional energy loss of a relativistic nucleus colliding with a photon of a given energy in the rest frame. The nucleus energy-loss rate is integrated over the photon angular distribution in the case of isotropic photons, and simple fits are provided.

  16. Effect of energetic ion loss on ICRF heating efficiency and energy confinement time in heliotrons

    International Nuclear Information System (INIS)

    Murakami, S.; Nakajima, N.; Okamoto, M.; Nuehrenberg, J.

    1999-06-01

    ICRF heating efficiency and the global energy confinement time during ICRF heating are investigated including the effect of energetic ion loss in heliotrons. The approximate formula of ICRF heating efficiency is derived using the results based on Monte Carlo simulations. The global energy confinement time including energetic ion effect can be expressed in terms of ICRF heating power, plasma density, and magnetic field strength in heliotrons. Our results in the CHS plasma show the systematic decrement of the global energy confinement time due to the energetic ion loss from the assumed energy confinement scaling law, which is consistent with the experimental observations. Also we apply our model to the ICRF minority heating in the LHD plasma in two cases of typical magnetic configurations. The clear increment of the global energy confinement time due to the stored energy of energetic tail ions is obtained in the 'orbit improved' configuration, while the decrement is observed in the 'standard' configuration. (author)

  17. Impact of potassium doping on the electronic structure of tetracene and pentacene: An electron energy-loss study

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Friedrich, E-mail: Friedrich.Roth@cfel.de [Center for Free-Electron Laser Science / DESY, Notkestraße 85, D-22607 Hamburg (Germany); Knupfer, Martin, E-mail: M.Knupfer@ifw-dresden.de [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany)

    2015-10-21

    We report the doping induced changes of the electronic structure of tetracene and pentacene probed by electron energy-loss spectroscopy in transmission. A comparison between the dynamic response of undoped and potassium-intercalated tetracene and pentacene emphasizes the appearance of a new excitation feature in the former gap upon potassium addition. Interestingly, the momentum dependency of this new excitation shows a negative dispersion. Moreover, the analysis of the C 1s and K 2p core-level excitation results in a significantly lower doping level compared to potassium doped picene, a recently discovered superconductor. Therefore, the present electronic structure investigations open a new pathway to better understand the exceptional differences between acenes and phenacene and their divergent behavior upon alkali doping.

  18. Black hole spectroscopy: Systematic errors and ringdown energy estimates

    Science.gov (United States)

    Baibhav, Vishal; Berti, Emanuele; Cardoso, Vitor; Khanna, Gaurav

    2018-02-01

    The relaxation of a distorted black hole to its final state provides important tests of general relativity within the reach of current and upcoming gravitational wave facilities. In black hole perturbation theory, this phase consists of a simple linear superposition of exponentially damped sinusoids (the quasinormal modes) and of a power-law tail. How many quasinormal modes are necessary to describe waveforms with a prescribed precision? What error do we incur by only including quasinormal modes, and not tails? What other systematic effects are present in current state-of-the-art numerical waveforms? These issues, which are basic to testing fundamental physics with distorted black holes, have hardly been addressed in the literature. We use numerical relativity waveforms and accurate evolutions within black hole perturbation theory to provide some answers. We show that (i) a determination of the fundamental l =m =2 quasinormal frequencies and damping times to within 1% or better requires the inclusion of at least the first overtone, and preferably of the first two or three overtones; (ii) a determination of the black hole mass and spin with precision better than 1% requires the inclusion of at least two quasinormal modes for any given angular harmonic mode (ℓ , m ). We also improve on previous estimates and fits for the ringdown energy radiated in the various multipoles. These results are important to quantify theoretical (as opposed to instrumental) limits in parameter estimation accuracy and tests of general relativity allowed by ringdown measurements with high signal-to-noise ratio gravitational wave detectors.

  19. Low-maintenance energy requirements of obese dogs after weight loss.

    Science.gov (United States)

    German, Alexander J; Holden, Shelley L; Mather, Nicola J; Morris, Penelope J; Biourge, Vincent

    2011-10-01

    Weight rebound after successful weight loss is a well-known phenomenon in humans and dogs, possibly due to the fact that energy restriction improves metabolic efficiency, reducing post-weight-loss maintenance energy requirements (MER). The aim of the present study was to estimate post-weight-loss MER in obese pet dogs that had successfully lost weight and did not subsequently rebound. A total of twenty-four obese dogs, successfully completing a weight management programme at the Royal Canin Weight Management Clinic, University of Liverpool (Wirral, UK), were included. In all dogs, a period of >14 d of stable weight ( lean tissue lost was negatively associated with post-weight-loss MER. MER are low after weight loss in obese pet dogs (typically only 10 % more than required during weight-loss MER), which has implications for what should constitute the optimal diet during this period. Preserving lean tissue during weight loss may maximise post-weight-loss MER and help prevent rebound.

  20. Energy loss straggling in Aluminium foils for Li and C ions in fractional energy loss limits (ΔE/E) ∼10-60%

    Science.gov (United States)

    Diwan, P. K.; Kumar, Sunil; Kumar, Shyam; Sharma, V.; Khan, S. A.; Avasthi, D. K.

    2016-02-01

    The energy loss straggling of Li and C ions in Al foils of various thicknesses has been measured, within the fractional energy loss limit (∆E/E) ∼ 10-60%. These measurements have been performed using the 15UD Pelletron accelerator facility available at Inter University Accelerator Centre (IUAC), New Delhi, India. The measured straggling values have been compared with the corresponding predicted values adopting popularly used collisional straggling formulations viz Bohr, Lindhard and Scharff, Bethe-Livingston, Titeica. In addition, the experimental data has been compared to the Yang et al. empirical formula and Close Form Model, recently proposed by Montanari et al. The straggling values derived by Titeica theory were found to be in better agreement with the measured values as compared to other straggling formulations. The charge-exchange straggling component has been estimated from the measured data based on Titeica's theory. Finally, a function of the ion effective charge and the energy loss fraction within the target has been fitted to the latter straggling component.

  1. High-Resolution, Long-Slit Spectroscopy of VY Canis Majoris: The Evidence for Localized High Mass Loss Events

    Science.gov (United States)

    Humphreys, Roberta M.; Davidson, Kris; Ruch, Gerald; Wallerstein, George

    2005-01-01

    High spatial and spectral resolution spectroscopy of the OH/IR supergiant VY CMa and its circumstellar ejecta reveals evidence for high mass loss events from localized regions on the star occurring over the past 1000 yr. The reflected absorption lines and the extremely strong K I emission lines show a complex pattern of velocities in the ejecta. We show that the large, dusty northwest arc, expanding at ~50 km s-1 with respect to the embedded star, is kinematically distinct from the surrounding nebulosity and was ejected about 400 yr ago. Other large, more filamentary loops were probably expelled as much as 800-1000 yr ago, whereas knots and small arcs close to the star resulted from more recent events 100-200 yr ago. The more diffuse, uniformly distributed gas and dust is surprisingly stationary, with little or no velocity relative to the star. This is not what we would expect for the circumstellar material from an evolved red supergiant with a long history of mass loss. We therefore suggest that the high mass loss rate for VY CMa is a measure of the mass carried out by these specific ejections accompanied by streams or flows of gas through low-density regions in the dust envelope. VY CMa may thus be our most extreme example of stellar activity, but our results also bring into question the evolutionary state of this famous star. In a separate appendix, we discuss the origin of the very strong K I and other rare emission lines in its spectrum.

  2. Energy Deficit Required for Rapid Weight Loss in Elite Collegiate Wrestlers.

    Science.gov (United States)

    Kondo, Emi; Sagayama, Hiroyuki; Yamada, Yosuke; Shiose, Keisuke; Osawa, Takuya; Motonaga, Keiko; Ouchi, Shiori; Kamei, Akiko; Nakajima, Kohei; Higaki, Yasuki; Tanaka, Hiroaki; Takahashi, Hideyuki; Okamura, Koji

    2018-04-26

    To determine energy density for rapid weight loss (RWL) of weight-classified sports, eight male elite wrestlers were instructed to lose 6% of body mass (BM) within 53 h. Energy deficit during the RWL was calculated by subtracting total energy expenditure (TEE) determined using the doubly labeled water method (DLW) from energy intake (EI) assessed with diet records. It was also estimated from body composition change estimated with the four-component model (4C) and other conventional methods. BM decreased significantly by 4.7 ± 0.5 kg (6.4 ± 0.5%). Total body water loss was the major component of the BM loss (71.0 ± 7.6%). TEE was 9446 ± 1422 kcal, and EI was 2366 ± 1184 kcal during the RWL of 53-h; therefore, the energy deficit was 7080 ± 1525 kcal. Thus, energy density was 1507 ± 279 kcal/kg ∆BM during the RWL, comparable with values obtained using the 4C, three-component model, dual energy X-ray absorptiometry, and stable isotope dilution. Energy density for RWL of wrestlers is lower than that commonly used (7400 or 7700 kcal/kg ΔBM). Although RWL is not recommended, we propose that commonly practiced extreme energy restriction such as 7400 or 7700 kcal/kg ΔBM during RWL appears to be meaningless.

  3. Energy Deficit Required for Rapid Weight Loss in Elite Collegiate Wrestlers

    Directory of Open Access Journals (Sweden)

    Emi Kondo

    2018-04-01

    Full Text Available To determine energy density for rapid weight loss (RWL of weight-classified sports, eight male elite wrestlers were instructed to lose 6% of body mass (BM within 53 h. Energy deficit during the RWL was calculated by subtracting total energy expenditure (TEE determined using the doubly labeled water method (DLW from energy intake (EI assessed with diet records. It was also estimated from body composition change estimated with the four-component model (4C and other conventional methods. BM decreased significantly by 4.7 ± 0.5 kg (6.4 ± 0.5%. Total body water loss was the major component of the BM loss (71.0 ± 7.6%. TEE was 9446 ± 1422 kcal, and EI was 2366 ± 1184 kcal during the RWL of 53-h; therefore, the energy deficit was 7080 ± 1525 kcal. Thus, energy density was 1507 ± 279 kcal/kg ∆BM during the RWL, comparable with values obtained using the 4C, three-component model, dual energy X-ray absorptiometry, and stable isotope dilution. Energy density for RWL of wrestlers is lower than that commonly used (7400 or 7700 kcal/kg ΔBM. Although RWL is not recommended, we propose that commonly practiced extreme energy restriction such as 7400 or 7700 kcal/kg ΔBM during RWL appears to be meaningless.

  4. Loss experience from natural phenomena hazards in the Department of Energy (50 years of natural phenomena hazard losses)

    International Nuclear Information System (INIS)

    Hill, J.R.

    1993-01-01

    This paper presents a historical prespective on losses due to natural hazard incidents (1943-1993) at Department of Energy (DOE) and predecessor agencies including the Atomic Energy Commission (AEC) and the Energy Research and Development Agency (ERDA). This paper also demonstrates how an existing DOE resource can be used to gain valuable insight into injury or property damage incidents. That resource is the Computerized Accident/Incident Reporting System (CAIRS) module of DOE's Safety Performance Measurement System. CAIRS data selected the 1981-1991 DOE injury/illness reports, from all the accident reports of the AEC that cited a natural phenomena hazard as either the direct or indirect cause of the injury/property damage. Specifically, injury or property damage reports were selected for analysis if they had a causal factor link to severe weather or natural phenomena hazard categories. Natural phenomena hazard categories are injury/property damage caused by hurricane/tornado, earthquake, lightning, or flood. Severe weather categories are injury/property damage associated with other than normal weather conditions. The lessons learned, as a result of reviewing case histories, are presented, as are suggestions on how to reduce the likelihood of future injuries/property damage as a result of similar events. A significant finding, is that most injuries and property damage were the result of an indirect causal link to a natural phenomena hazard and thus, may be more preventable than previously thought possible. The primary message, however, is that CAIRS and other incident data bases are valuable resources and should be considered for use by those interested in identifying new ways of protecting the health and safety of the worker and for reducing building losses due to the effects of natural phenomena hazards

  5. The use of logarithmic pulse height and energy scales in organic scintillator spectroscopy

    International Nuclear Information System (INIS)

    Whittlestone, S.

    1980-01-01

    The use of logarithmic pulse height and energy scales is advantageous for organic for organic scintillator neutron spectroscopy, providing an expanded dynamic range and economy of computer usage. An experimental logarithmic pulse height analysis system is shown to be feasible. A pulse height spectrum from a neutron measurement has been analysed using linear and logarithmic scales; the latter reduced the computer storage requirements by a factor of 13 and analysis time by 8.7, and there was no degradation of the analysed spectrum. Most of the arguments favouring use of logarithmic scales apply equally well to other types of scintillation spectroscopy. (orig.)

  6. Allotropic effects on the energy loss of swift H+ and He+ ion beams through thin foils

    International Nuclear Information System (INIS)

    Garcia-Molina, Rafael; Abril, Isabel; Denton, Cristian D.; Heredia-Avalos, Santiago

    2006-01-01

    We have developed a theoretical treatment and a simulation code to study the energy loss of swift H + and He + ion beams interacting with thin foils of different carbon allotropes. The former is based on the dielectric formalism, and the latter combines Monte Carlo with the numerical solution of the motion equation for each projectile to describe its trajectory and interactions through the target. The capabilities of both methods are assessed by the reasonably good agreement between their predictions and the experimental results, for a wide range of projectile energies and target characteristics. Firstly, we apply the theoretical procedure to calculate the stopping cross sections for H + and He + beams in foils of different allotropic forms of carbon (such as diamond, graphite, amorphous carbon, glassy carbon and C 60 -fullerite), as a function of the projectile energy. We take into account the electronic structure of the projectile, as well as the different charge states it can acquire, the energy loss associated to the electronic capture and loss processes, the polarization of the projectile, and a realistic description of the target. On the other hand, the simulation code is used to evaluate the energy distributions of swift H + and He + ion beams when traversing several foils of the above mentioned allotropic forms of carbon, in order to analyze the influence of the chemical and physical state of the target in the projectile energy loss. These allotropic effects are found to become more important around the maximum of the stopping cross-section

  7. Understanding Energy Loss in Organic Solar Cells: Toward a New Efficiency Regime

    KAUST Repository

    Menke, S. Matthew; Ran, Niva A.; Bazan, Guillermo C.; Friend, Richard H.

    2017-01-01

    Reducing energy and voltage loss is an imperative area of improvement for the design of organic solar cells (OSCs). Both in the context of charge generation and charge recombination, significant amounts of energy are lost even in state-of-the-art OSCs compared with their inorganic counterparts. Through a set of recent examples, however, we show that (1) charge generation can proceed with high quantum efficiency even in the absence of an offset energy at the donor-acceptor interface and (2) non-radiative charge recombination may be mitigated by considering systems with distinct properties of the interfacial charge-transfer state. To capitalize on these recent advances in understanding, we provide three actionable paths forward that aim to better identify, process, and characterize low energy loss systems: incorporating consistent and accurate measurements for energy levels, moving away from photoluminescence quenching, and exploring blends with reduced miscibility.

  8. Understanding Energy Loss in Organic Solar Cells: Toward a New Efficiency Regime

    KAUST Repository

    Menke, S. Matthew

    2017-10-19

    Reducing energy and voltage loss is an imperative area of improvement for the design of organic solar cells (OSCs). Both in the context of charge generation and charge recombination, significant amounts of energy are lost even in state-of-the-art OSCs compared with their inorganic counterparts. Through a set of recent examples, however, we show that (1) charge generation can proceed with high quantum efficiency even in the absence of an offset energy at the donor-acceptor interface and (2) non-radiative charge recombination may be mitigated by considering systems with distinct properties of the interfacial charge-transfer state. To capitalize on these recent advances in understanding, we provide three actionable paths forward that aim to better identify, process, and characterize low energy loss systems: incorporating consistent and accurate measurements for energy levels, moving away from photoluminescence quenching, and exploring blends with reduced miscibility.

  9. Low-energy electron energy losses and inelastic mean free paths in zinc, selenium, and zinc selenide

    Energy Technology Data Exchange (ETDEWEB)

    Bourke, J.D.; Chantler, C.T., E-mail: chantler@unimelb.edu.au

    2014-10-15

    We compute low-energy optical energy loss spectra for the elemental solids zinc and selenium, and for the binary compound zinc selenide. The optical data are transformed via a constrained partial-pole algorithm to produce momentum-dependent electron energy loss spectra and electron inelastic mean free paths. This enables a comparison between the electron scattering behaviour in a compound solid and its constituent elements. Results cannot be explained by aggregation methods or commonly used universal curves, and prove that new approaches are required. Our work demonstrates new capabilities for the determination of fundamental material properties for a range of structures previously inaccessible to established theoretical models, and at energy levels inaccessible to most experimental techniques.

  10. Low-energy electron energy losses and inelastic mean free paths in zinc, selenium, and zinc selenide

    International Nuclear Information System (INIS)

    Bourke, J.D.; Chantler, C.T.

    2014-01-01

    We compute low-energy optical energy loss spectra for the elemental solids zinc and selenium, and for the binary compound zinc selenide. The optical data are transformed via a constrained partial-pole algorithm to produce momentum-dependent electron energy loss spectra and electron inelastic mean free paths. This enables a comparison between the electron scattering behaviour in a compound solid and its constituent elements. Results cannot be explained by aggregation methods or commonly used universal curves, and prove that new approaches are required. Our work demonstrates new capabilities for the determination of fundamental material properties for a range of structures previously inaccessible to established theoretical models, and at energy levels inaccessible to most experimental techniques

  11. How strongly does appetite counter weight loss? Quantification of the feedback control of human energy intake

    Science.gov (United States)

    Polidori, David; Sanghvi, Arjun; Seeley, Randy; Hall, Kevin D.

    2016-01-01

    Objective To quantify the feedback control of energy intake in response to long-term covert manipulation of energy balance in free-living humans. Methods We used a validated mathematical method to calculate energy intake changes during a 52 week placebo-controlled trial in 153 patients treated with canagliflozin, a sodium glucose co-transporter inhibitor that increases urinary glucose excretion thereby resulting in weight loss without patients being directly aware of the energy deficit. We analyzed the relationship between the body weight time course and the calculated energy intake changes using principles from engineering control theory. Results We discovered that weight loss leads to a proportional increase in appetite resulting in eating above baseline by ~100 kcal/day per kg of lost weight – an amount more than 3-fold larger than the corresponding energy expenditure adaptations. Conclusions While energy expenditure adaptations are often thought to be the main reason for slowing of weight loss and subsequent regain, feedback control of energy intake plays an even larger role and helps explain why long-term maintenance of a reduced body weight is so difficult. PMID:27804272

  12. Jet suppression and the flavor dependence of partonic energy loss with ATLAS

    Energy Technology Data Exchange (ETDEWEB)

    Kosek, Tomas

    2016-12-15

    In relativistic heavy ion collisions, a hot medium with a high density of unscreened color charges is produced. One manifestation of the energy loss of jets propagating through the medium is a lower yield of jets and hadrons emerging from this medium than expected in the absence of medium effects. Therefore modifications of the jet yield are directly sensitive to the energy loss mechanism. Furthermore, jets with different flavor content are expected to be affected by the medium in different ways. In this publication, the latest ATLAS results on single hadron suppression along with the complementary measurements of single jet suppression are presented. Rapidity dependence, which is sensitive to the relative energy loss between quark and gluon jets, is discussed. Finally, a new measurement of jet fragmentation functions is presented.

  13. Energy loss of MeV protons specularly reflected from metal surfaces

    International Nuclear Information System (INIS)

    Juaristi, J.I.; Garcia de Abajo, F.J.; Echenique, P.M.

    1996-01-01

    A parameter-free model is presented to study the energy loss of fast protons specularly reflected from metal surfaces. The contributions to the energy loss from excitation of valence-band electrons and ionization of localized target-atom electronic states are calculated separately. The former is calculated from the induced surface wake potential using linear response theory and the specular-reflection model, while the latter is calculated in the first Born approximation. The results obtained are in good agreement with available experimental data. However, the experimental qualitative trend of the energy loss as a function of the angle of incidence is obtained when the valence-band electron model is replaced by localized target atom electron states, though with a worse quantitative agreement. copyright 1996 The American Physical Society

  14. Prediction of transmission loss through an aircraft sidewall using statistical energy analysis

    Science.gov (United States)

    Ming, Ruisen; Sun, Jincai

    1989-06-01

    The transmission loss of randomly incident sound through an aircraft sidewall is investigated using statistical energy analysis. Formulas are also obtained for the simple calculation of sound transmission loss through single- and double-leaf panels. Both resonant and nonresonant sound transmissions can be easily calculated using the formulas. The formulas are used to predict sound transmission losses through a Y-7 propeller airplane panel. The panel measures 2.56 m x 1.38 m and has two windows. The agreement between predicted and measured values through most of the frequency ranges tested is quite good.

  15. Energy Level Tuning of Poly(phenylene-alt-dithienobenzothiadiazole)s for Low Photon Energy Loss Solar Cells.

    Science.gov (United States)

    Heuvel, Ruurd; van Franeker, Jacobus J; Janssen, René A J

    2017-03-01

    Six poly(phenylene- alt -dithienobenzothiadiazole)-based polymers have been synthesized for application in polymer-fullerene solar cells. Hydrogen, fluorine, or nitrile substitution on benzo-thiadiazole and alkoxy or ester substitution on the phenylene moiety are investigated to reduce the energy loss per converted photon. Power conversion efficiencies (PCEs) up to 6.6% have been obtained. The best performance is found for the polymer-fullerene combination with distinct phase separation and crystalline domains. This improves the maximum external quantum efficiency for charge formation and collection to 66%. The resulting higher photocurrent compensates for the relatively large energy loss per photon ( E loss = 0.97 eV) in achieving a high PCE. By contrast, the poly-mer that provides a reduced energy loss ( E loss = 0.49 eV) gives a lower photocurrent and a reduced PCE of 1.8% because the external quantum efficiency of 17% is limited by a suboptimal morphology and a reduced driving force for charge transfer.

  16. Energy and angle resolved ion scattering spectroscopy: new possibilities for surface analysis

    International Nuclear Information System (INIS)

    Hellings, G.J.A.

    1986-01-01

    In this thesis the design and development of a novel, very sensitive and high-resolving spectrometer for surface analysis is described. This spectrometer is designed for Energy and Angle Resolved Ion Scattering Spectroscopy (EARISS). There are only a few techniques that are sensitive enough to study the outermost atomic layer of surfaces. One of these techniques, Low-Energy Ion Scattering (LEIS), is discussed in chapter 2. Since LEIS is destructive, it is important to make a very efficient use of the scattered ions. This makes it attractive to simultaneously carry out energy and angle dependent measurements (EARISS). (Auth.)

  17. Functional materials for information and energy technology: Insights by photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Müller, Martina; Nemšák, Slavomír; Plucinski, Lukasz; Schneider, Claus M.

    2016-01-01

    Highlights: • Photoemission spectro/microscopy studies of functional material systems. • Hard X-ray photoemission spectroscopy from magnetic semiconductors and insulators. • Information depth studies in hard X-ray photoemission microscopy. • Soft X-ray standing wave ambient pressure photoemission spectroscopy from liquid films. - Abstract: The evolution of both information and energy technology is intimately connected to complex condensed matter systems, the properties of which are determined by electronic and chemical interactions and processes on a broad range of length and time scales. Dedicated photoelectron spectroscopy and spectromicroscopy experiments can provide important insights into fundamental phenomena and applied functionalities. We discuss some recent methodological developments with application to relevant questions in spintronics, and towards operando studies of resistive switching and electrochemical processes.

  18. Laser field effects on the transport phenomena: Energy loss and stopping power

    International Nuclear Information System (INIS)

    Torres Silva, H.; Sakanaka, P.H.

    1990-01-01

    The energy loss method has been applied to a large variety of transport problems in optics, solid-state and fusion research. In these papers, however, the transport equations were linearized, so there are no multiphoton interaction. On the other hand, Bivona et al. (1982) [2] have shown that, for a one-component plasma, the strong field effects would be only of academic interest. On the basis of the center of mass approach [3], a generalization of the energy loss rate which is in accordance with the recent results of Arista et al. (1989) [4] is obtained. (Author)

  19. Modelling of prompt losses of high energy charged particles in Tokamaks

    International Nuclear Information System (INIS)

    Dillner, Oe.; Anderson, D.; Hamnen, H.; Lisak, M.

    1990-01-01

    A simple analytical expression for the total prompt loss fraction of high energy charged particles in an axisymmetric Tokamak is derived. The results are compared with predictions obtained from numerical simulations and show good agreement. An application is made to sawtooth induced changes in the losses of fusion generated high energy charged particles. Particular emphasis is given to the importance of sawtooth induced profile changes of the background ion densities and temperature as well as to redistribution of particles which have accumulated during the sawtooth rise but are being lost by redistribution at the sawtooth crash. (au)

  20. Comparing energy loss and pperpendicular -broadening in perturbative QCD with strong coupling N=4 SYM theory

    International Nuclear Information System (INIS)

    Dominguez, Fabio; Marquet, C.; Mueller, A.H.; Wu Bin; Xiao, Bo-Wen

    2008-01-01

    We compare medium induced energy loss and p perpendicular -broadening in perturbative QCD with that of the trailing string picture of SYM theory. We consider finite and infinite extent matter as well as relativistic heavy quarks which correspond to those being produced in the medium or external to it. When expressed in terms of the appropriate saturation momentum, we find identical parametric forms for energy loss in perturbative QCD and SYM theory. We find simple correspondences between p perpendicular -broadening in QCD and in SYM theory although p perpendicular -broadening is radiation dominated in SYM theory and multiple scattering dominated in perturbative QCD

  1. More than 30 per cent energy savings possible with LEDs in gerbera : substantial energy savings and little loss in production

    NARCIS (Netherlands)

    Helm, van der F.P.M.

    2015-01-01

    By installing LED-lighting and limiting it to 80 instead of 100 μmol gerbera growers can save 30 per cent on energy without any great loss in production, according to research. Light integration and interlighting don’t yet deliver any savings.

  2. Intermittent Moderate Energy Restriction Improves Weight Loss Efficiency in Diet-Induced Obese Mice.

    Directory of Open Access Journals (Sweden)

    Radhika V Seimon

    Full Text Available Intermittent severe energy restriction is popular for weight management. To investigate whether intermittent moderate energy restriction may improve this approach by enhancing weight loss efficiency, we conducted a study in mice, where energy intake can be controlled.Male C57/Bl6 mice that had been rendered obese by an ad libitum diet high in fat and sugar for 22 weeks were then fed one of two energy-restricted normal chow diets for a 12-week weight loss phase. The continuous diet (CD provided 82% of the energy intake of age-matched ad libitum chow-fed controls. The intermittent diet (ID provided cycles of 82% of control intake for 5-6 consecutive days, and ad libitum intake for 1-3 days. Weight loss efficiency during this phase was calculated as (total weight change ÷ [(total energy intake of mice on CD or ID-(total average energy intake of controls]. Subsets of mice then underwent a 3-week weight regain phase involving ad libitum re-feeding.Mice on the ID showed transient hyperphagia relative to controls during each 1-3-day ad libitum feeding period, and overall ate significantly more than CD mice (91.1±1.0 versus 82.2±0.5% of control intake respectively, n = 10, P<0.05. There were no significant differences between CD and ID groups at the end of the weight loss or weight regain phases with respect to body weight, fat mass, circulating glucose or insulin concentrations, or the insulin resistance index. Weight loss efficiency was significantly greater with ID than with CD (0.042±0.007 versus 0.018±0.001 g/kJ, n = 10, P<0.01. Mice on the CD exhibited significantly greater hypothalamic mRNA expression of proopiomelanocortin (POMC relative to ID and control mice, with no differences in neuropeptide Y or agouti-related peptide mRNA expression between energy-restricted groups.Intermittent moderate energy restriction may offer an advantage over continuous moderate energy restriction, because it induces significantly greater weight loss relative

  3. Energy-loss of He ions in carbon allotropes studied by elastic resonance in backscattering spectra

    Energy Technology Data Exchange (ETDEWEB)

    Tosaki, Mitsuo, E-mail: tosaki.mitsuo.3v@kyoto-u.ac.jp [Radioisotope Research Center, Kyoto University, Kyoto 606-8501 (Japan); Rauhala, Eero [Department of Physics, University of Helsinki (Finland)

    2015-10-01

    Backscattering spectra for {sup 4}He ions incident on carbon allotropes have been measured in the energy range from 4.30 to 4.95 MeV in steps of 50–100 keV at scattering angles of 106° and 170°. We used three carbon allotropes: graphite, diamond and amorphous carbon. For all these allotropes, we can observe the sharp ({sup 4}He, {sup 12}C) elastic nuclear resonance at the He ion energy of 4.265 MeV in the backscattering spectra. By varying the incident He energy, we have systematically analyzed the profiles of the resonance peaks to study the energy-loss processes: stopping cross-sections and energy-loss straggling around the interesting region of the stopping maximum at about 500 keV. We focus on the resonance profiles and investigate an allotropic effect concerning the energy-loss. Furthermore, an energy bunching effect on the straggling is presented and the mechanism is discussed.

  4. Thermal energy storage and losses in a room-Trombe wall system located in Mexico

    International Nuclear Information System (INIS)

    Hernández-López, I.; Xamán, J.; Chávez, Y.; Hernández-Pérez, I.; Alvarado-Juárez, R.

    2016-01-01

    A thermal evaluation of a R-TW system (room with a Trombe wall) is presented. Hourly climatic data of the coldest and the warmest days of 2014 was used to assess the behavior of the R-TW in two cities of Mexico with cold climate (Huitzilac and Toluca). The simulations were done with an in-house code based on the Finite Volume Method. It was found that thermal energy losses through the semitransparent wall are about 60% of the solar radiation incident on the system (G_s_o_l). Despite of the thermal losses, the system gets enough energy to keep the air inside the room with a temperature above 35 °C. For both cities during the coldest day, the maximum energy stored is about 109 MJ and during the warmest day is about 70 MJ. This energy is supplied from the storage wall to the air inside the room during periods without insolation. - Highlights: • Thermal performance of a Room-Trombe Wall system was evaluated under two cold cities. • Thermal energy losses through the semitransparent wall were about 60% of the solar radiation incident of the system. • The maximum energy stored by the Trombe Wall was 109 MJ during the coldest day. • The maximum energy stored by the Trombe Wall was 70 MJ during the warmest day.

  5. Energy homeostasis and appetite regulating hormones as predictors of weight loss in men and women.

    Science.gov (United States)

    Williams, Rebecca L; Wood, Lisa G; Collins, Clare E; Morgan, Philip J; Callister, Robin

    2016-06-01

    Sex differences in weight loss are often seen despite using the same weight loss program. There has been relatively little investigation of physiological influences on weight loss success in males and females, such as energy homeostasis and appetite regulating hormones. The aims were to 1) characterise baseline plasma leptin, ghrelin and adiponectin concentrations in overweight and obese males and females, and 2) determine whether baseline concentrations of these hormones predict weight loss in males and females. Subjects were overweight or obese (BMI 25-40 kg/m(2)) adults aged 18-60 years. Weight was measured at baseline, and after three and six months participation in a weight loss program. Baseline concentrations of leptin, adiponectin and ghrelin were determined by enzyme-linked immunosorbent assay (ELISA). An independent t-test or non-parametric equivalent was used to determine any differences between sex. Linear regression determined whether baseline hormone concentrations were predictors of six-month weight change. Females had significantly higher baseline concentrations of leptin, adiponectin and unacylated ghrelin as well as ratios of leptin:adiponectin and leptin:ghrelin. The ratio of acylated:unacylated ghrelin was significantly higher in males. In males and females, a higher baseline concentration of unacylated ghrelin predicted greater weight loss at six months. Additionally in females, higher baseline total ghrelin predicted greater weight loss and a higher ratio of leptin:ghrelin predicted weight gain at six months. A higher pre-weight-loss plasma concentration of unacylated ghrelin is a modest predictor of weight loss success in males and females, while a higher leptin:ghrelin ratio is a predictor of weight loss failure in females. Further investigation is required into what combinations and concentrations of these hormones are optimal for weight loss success. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Energy reduction in buildings in temperate and tropic regions utilizing a heat loss measuring device

    DEFF Research Database (Denmark)

    Sørensen, Lars Schiøtt

    2012-01-01

    There exist two ordinary ways to obtain global energy efficiency. One way is to make improvements on the energy production and supply side, and the other way is, in general, to reduce the consume of energy in the society. This paper has focus on the latter and especially the consume of energy...... for heating up, and cooling down our houses. There is a huge energy saving potential on this area reducing both the World climate problems and economy challenges as well. Heating of buildings in Denmark counts for approximately 40% of the entire national energy consume. Of this reason a reduction of heat...... losses from building envelopes are of great impor­tance in order to reach the Bologna CO2-emission reduction goals. Energy renovation of buildings is a topic of huge focus around the world these years. Not only expenses for heating in the tempered and arctic regions are of importance, but also expenses...

  7. Precise measurements of energy loss straggling for swift heavy ions in polymers

    Science.gov (United States)

    Rani, Bindu; Neetu; Sharma, Kalpana; Diwan, P. K.; Kumar, Shyam

    2016-11-01

    The energy loss straggling measurements for heavy ions with Z = 3-22 (∼0.2-2.5 MeV/u) in PEN (C7H5O2) and PET (C10H8O4) polymers have been carried out utilizing the swift heavy ion beam facility from 15UD Pelletron accelerator at Inter University Accelerator Centre (IUAC), New Delhi, India. The recorded spectra are analyzed in such a way that the Straggling associated with energy loss process could be measured in a systematic manner at any selected value of energy, in terms of per unit thickness of the absorber, at any desired energy intervals. The measured values have been compared with the calculated values obtained from the most commonly used Bethe-Livingston formulations applicable for collisional straggling. The results are tried to be understood in terms of the effective charge on the impinging ion within the absorber. Some interesting trends are observed.

  8. Energy loss distributions of 7 TeV protons channeled in a bent silicon crystals

    Directory of Open Access Journals (Sweden)

    Stojanov Nace

    2013-01-01

    Full Text Available The energy loss distributions of relativistic protons axially channeled through the bent Si crystals, with the constant curvature radius, R = 50 m, are studied here. The proton energy is 7 TeV and the thickness of the crystal is varied from 1 mm to 5 mm, which corresponds to the reduced crystal thickness, L, from 2.1 to 10.6, respectively. The proton energy was chosen in accordance with the large hadron collider project, at the European Organization for Nuclear Research, in Geneva, Switzerland. The energy loss distributions of the channeled protons were generated by the computer simulation method using the numerical solution of the proton equations of motion in the transverse plane. Dispersion of the proton scattering angle caused by its collisions with the crystal’s electrons was taken into account. [Projekat Ministarstva nauke Republike Srbije, br. III 45006

  9. Direct observation and theory of trajectory-dependent electronic energy losses in medium-energy ion scattering.

    Science.gov (United States)

    Hentz, A; Parkinson, G S; Quinn, P D; Muñoz-Márquez, M A; Woodruff, D P; Grande, P L; Schiwietz, G; Bailey, P; Noakes, T C Q

    2009-03-06

    The energy spectrum associated with scattering of 100 keV H+ ions from the outermost few atomic layers of Cu(111) in different scattering geometries provides direct evidence of trajectory-dependent electronic energy loss. Theoretical simulations, combining standard Monte Carlo calculations of the elastic scattering trajectories with coupled-channel calculations to describe inner-shell ionization and excitation as a function of impact parameter, reproduce the effects well and provide a means for far more complete analysis of medium-energy ion scattering data.

  10. Quantitative evaluation of spatial scale of carrier trapping at grain boundary by GHz-microwave dielectric loss spectroscopy

    Science.gov (United States)

    Choi, W.; Tsutsui, Y.; Miyakai, T.; Sakurai, T.; Seki, S.

    2017-11-01

    Charge carrier mobility is an important primary parameter for the electronic conductive materials, and the intrinsic limit of the mobility has been hardly access by conventional direct-current evaluation methods. In the present study, intra-grain hole mobility of pentacene thin films was estimated quantitatively using microwave-based dielectric loss spectroscopy (time-resolved microwave conductivity measurement) in alternating current mode of charge carrier local motion. Metal-insulator-semiconductor devices were prepared with different insulating polymers or substrate temperature upon vacuum deposition of the pentacene layer, which afforded totally four different grain-size conditions of pentacene layers. Under the condition where the local motion was determined by interfacial traps at the pentacene grain boundaries (grain-grain interfaces), the observed hole mobilities were plotted against the grain sizes, giving an excellent correlation fit successfully by a parabolic function representative of the boarder length. Consequently, the intra-grain mobility and trap-release time of holes were estimated as 15 cm2 V-1 s-1 and 9.4 ps.

  11. A precise measurement of 180 GeV muon energy losses in iron

    Czech Academy of Sciences Publication Activity Database

    Amaral, P.; Amorim, A.; Davídek, T.; Krivková, P.; Leitner, R.; Lokajíček, Miloš; Němeček, Stanislav; Suk, M.; Valkar, S.; Zaitsev, A.

    2001-01-01

    Roč. 20, - (2001), s. 487-495 ISSN 1434-6044 R&D Projects: GA MPO RP-4210/69 Institutional research plan: CEZ:AV0Z1010920 Keywords : energy loss spectrum * muons * hadron Tile calorimeter * CERN SPS * production of electron-positron pairs * energetic knock-on elecktrons * ion elastic form factor correction Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 5.194, year: 2001

  12. Energy losses (gains) of massive coloured particles in stochastic colour medium

    International Nuclear Information System (INIS)

    Leonidov, A.; Rossijskaya Akademiya Nauk, Moscow

    1995-01-01

    The propagation of massive coloured particles in stochastic background chromoelectric field is studied using the semiclassical equations of motion. Depending on the nature of the stochastic background we obtain the formulae for the energy losses of heavy coloured projectile in nonperturbative hadronic medium and for the energy gains in the stochastic field present, e.g., in the turbulent plasma. The result appears to be significantly dependent on the form of the correlation function of stochastic external field. (orig.)

  13. Electron-energy-loss spectral library and its application to materials science

    Energy Technology Data Exchange (ETDEWEB)

    Zaluzec, N.J.

    1983-09-01

    An electron energy loss spectral library can be an invaluable tool in materials research from a fundamental as well as a practical standpoint. Although it will not alleviate all the complications associated with quantification, this type of library can help to elucidate details of spectral profiles previously found intractable. This work was supported by the US Department of Energy. The author also wishes to express his gratitude to the organizing committee for partial financial support provided to attend this meeting.

  14. Fusion-product energy loss in inertial confinement fusion plasmas with applications to target burns

    International Nuclear Information System (INIS)

    Harris, D.B.; Miley, G.H.

    1984-01-01

    Inertial confinement fusion (ICF) has been proposed as a competitor to magnetic fusion in the drive towards energy production, but ICF target performance still contains many uncertainties. One such area is the energy-loss rate of fusion products. This situation is due in part to the unique plasma parameters encountered in ICF plasmas which are compressed to more than one-thousand times solid density. The work presented here investigates three aspects of this uncertainty

  15. Mode and climatic factors effect on energy losses in transient heat modes of transmission lines

    Science.gov (United States)

    Bigun, A. Ya; Sidorov, O. A.; Osipov, D. S.; Girshin, S. S.; Goryunov, V. N.; Petrova, E. V.

    2018-01-01

    Electrical energy losses increase in modern grids. The losses are connected with an increase in consumption. Existing models of electric power losses estimation considering climatic factors do not allow estimating the cable temperature in real time. Considering weather and mode factors in real time allows to meet effectively and safely the consumer’s needs to minimize energy losses during transmission, to use electric power equipment effectively. These factors increase an interest in the evaluation of the dynamic thermal mode of overhead transmission lines conductors. The article discusses an approximate analytic solution of the heat balance equation in the transient operation mode of overhead lines based on the least squares method. The accuracy of the results obtained is comparable with the results of solving the heat balance equation of transient thermal mode with the Runge-Kutt method. The analysis of mode and climatic factors effect on the cable temperature in a dynamic thermal mode is presented. The calculation of the maximum permissible current for variation of weather conditions is made. The average electric energy losses during the transient process are calculated with the change of wind, air temperature and solar radiation. The parameters having the greatest effect on the transmission capacity are identified.

  16. Extended defect related energy loss in CVD diamond revealed by spectrum imaging in a dedicated STEM

    International Nuclear Information System (INIS)

    Bangert, U.; Harvey, A.J.; Schreck, M.; Hoermann, F.

    2005-01-01

    This article aims at investigations of the low EEL region in the wide band gap system diamond. The advent of the UHV Enfina electron energy loss spectrometer combined with Digital Micrograph acquisition and processing software has made reliable detection of absorption losses below 10 eV possible. Incorporated into a dedicated STEM this instrumentation allows the acquisition of spectral information via spectrum maps (spectrum imaging) of sample areas hundreds of nanometers across, with nanometers pixel sizes, adequate spectrum statistics and 0.3 eV energy resolution, in direct correlation with microstructural features in the mapping area. We aim at discerning defect related losses at band gap energies, and discuss different routes to simultaneously process and analyse the spectra in a map. This involves extracting the zero loss peak from each spectrum and constructing ratio maps from the intensities in two energy windows, one defect related and one at a higher, crystal bandstructure dominated energy. This was applied to the residual spectrum maps and their first derivatives. Secondly, guided by theoretical EEL spectra calculations, the low loss spectra were fitted by a series of gaussian distributions. Pixel maps were constructed from amplitude ratios of gaussians, situated in the defect and the unaffected energy regime. The results demonstrate the existence of sp 2 -bonded carbon in the vicinity of stacking faults and partial dislocations in CVD diamond as well as additional states below conduction band, tailing deep into the band gap, at a node in a perfect dislocation. Calculated EEL spectra of shuffle dislocations give similar absorption features at 5-8 eV, and it is thought that this common feature is due to sp 2 -type bonding

  17. Note: Electron energy spectroscopy mapping of surface with scanning tunneling microscope.

    Science.gov (United States)

    Li, Meng; Xu, Chunkai; Zhang, Panke; Li, Zhean; Chen, Xiangjun

    2016-08-01

    We report a novel scanning probe electron energy spectrometer (SPEES) which combines a double toroidal analyzer with a scanning tunneling microscope to achieve both topography imaging and electron energy spectroscopy mapping of surface in situ. The spatial resolution of spectroscopy mapping is determined to be better than 0.7 ± 0.2 μm at a tip sample distance of 7 μm. Meanwhile, the size of the field emission electron beam spot on the surface is also measured, and is about 3.6 ± 0.8 μm in diameter. This unambiguously demonstrates that the spatial resolution of SPEES technique can be much better than the size of the incident electron beam.

  18. Note: Electron energy spectroscopy mapping of surface with scanning tunneling microscope

    Energy Technology Data Exchange (ETDEWEB)

    Li, Meng; Xu, Chunkai, E-mail: xuck@ustc.edu.cn, E-mail: xjun@ustc.edu.cn; Zhang, Panke; Li, Zhean; Chen, Xiangjun, E-mail: xuck@ustc.edu.cn, E-mail: xjun@ustc.edu.cn [Hefei National Laboratory for Physical Science at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China)

    2016-08-15

    We report a novel scanning probe electron energy spectrometer (SPEES) which combines a double toroidal analyzer with a scanning tunneling microscope to achieve both topography imaging and electron energy spectroscopy mapping of surface in situ. The spatial resolution of spectroscopy mapping is determined to be better than 0.7 ± 0.2 μm at a tip sample distance of 7 μm. Meanwhile, the size of the field emission electron beam spot on the surface is also measured, and is about 3.6 ± 0.8 μm in diameter. This unambiguously demonstrates that the spatial resolution of SPEES technique can be much better than the size of the incident electron beam.

  19. Note: Electron energy spectroscopy mapping of surface with scanning tunneling microscope

    International Nuclear Information System (INIS)

    Li, Meng; Xu, Chunkai; Zhang, Panke; Li, Zhean; Chen, Xiangjun

    2016-01-01

    We report a novel scanning probe electron energy spectrometer (SPEES) which combines a double toroidal analyzer with a scanning tunneling microscope to achieve both topography imaging and electron energy spectroscopy mapping of surface in situ. The spatial resolution of spectroscopy mapping is determined to be better than 0.7 ± 0.2 μm at a tip sample distance of 7 μm. Meanwhile, the size of the field emission electron beam spot on the surface is also measured, and is about 3.6 ± 0.8 μm in diameter. This unambiguously demonstrates that the spatial resolution of SPEES technique can be much better than the size of the incident electron beam.

  20. A tunable low-energy photon source for high-resolution angle-resolved photoemission spectroscopy

    International Nuclear Information System (INIS)

    Harter, John W.; Monkman, Eric J.; Shai, Daniel E.; Nie Yuefeng; Uchida, Masaki; Burganov, Bulat; Chatterjee, Shouvik; King, Philip D. C.; Shen, Kyle M.

    2012-01-01

    We describe a tunable low-energy photon source consisting of a laser-driven xenon plasma lamp coupled to a Czerny-Turner monochromator. The combined tunability, brightness, and narrow spectral bandwidth make this light source useful in laboratory-based high-resolution photoemission spectroscopy experiments. The source supplies photons with energies up to ∼7 eV, delivering under typical conditions >10 12 ph/s within a 10 meV spectral bandwidth, which is comparable to helium plasma lamps and many synchrotron beamlines. We first describe the lamp and monochromator system and then characterize its output, with attention to those parameters which are of interest for photoemission experiments. Finally, we present angle-resolved photoemission spectroscopy data using the light source and compare its performance to a conventional helium plasma lamp.

  1. Understanding interface properties from high kinetic energy photoelectron spectroscopy and first principles theory

    International Nuclear Information System (INIS)

    Granroth, Sari; Olovsson, Weine; Holmstroem, Erik; Knut, Ronny; Gorgoi, Mihaela; Svensson, Svante; Karis, Olof

    2011-01-01

    Advances in instrumentation regarding 3rd generation synchrotron light sources and electron spectrometers has enabled the field of high kinetic energy photoelectron spectroscopy (HIKE) (also often denoted hard X-ray photoelectron spectroscopy (HX-PES or HAXPES)). Over the last years, the amount of investigations that relies on the HIKE method has increased dramatically and can arguably be said to have given a rebirth of the interest in photoelectron spectroscopy in many areas. It is in particular the much increased mean free path at higher kinetic energies in combination with the elemental selectivity of the core level spectroscopies in general that has lead to this fact, as it makes it possible to investigate the electronic structure of materials with a substantially reduced surface sensitivity. In this review we demonstrate how HIKE can be used to investigate the interface properties in multilayer systems. Relative intensities of the core level photoelectron peaks and their chemical shifts derived from binding energy changes are found to give precise information on physico-chemical properties and quality of the buried layers. Interface roughening, including kinetic properties such as the rate of alloying, and temperature effects on the processes can be analyzed quantitatively. We will also provide an outline of the theoretical framework that is used to support the interpretation of data. We provide examples from our own investigations of multilayer systems which comprises both systems of more model character and a multilayer system very close to real applications in devices that are considered to be viable alternative to the present read head technology. The experimental data presented in this review is exclusively recorded at the BESSY-II synchrotron at the Helmholtz-Zentrum Berlin fuer Materialien und Energie. This HIKE facility is placed at the bending magnet beamline KMC-1, which makes it different from several other facilities which relies on undulators as

  2. Energy Deposition in Adjacent LHC Superconducting Magnets from Beam Loss at LHC Transfer Line Collimators

    CERN Document Server

    Beavan, S; Kain, V

    2006-01-01

    Injection intensities for the LHC are over an order of magnitude above the damage threshold. The collimation system in the two transfer lines is designed to dilute the beam sufficiently to avoid damage in case of accidental beam loss or mis-steered beam. To maximise the protection for the LHC most of the collimators are located in the last 300 m upstream of the injection point where the transfer lines approach the LHC machine. To study the issue of possible quenches following beam loss at the collimators part of the collimation section in one of the lines, TI 8, together with the adjacent part of the LHC has been modeled in FLUKA. The simulated energy deposition in the LHC for worst-case accidental losses and as well as for losses expected during a normal filling is presented.

  3. Polarization correction in the theory of energy losses by charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Makarov, D. N., E-mail: makarovd0608@yandex.ru; Matveev, V. I. [Lomonosov Northern (Arctic) Federal University (Russian Federation)

    2015-05-15

    A method for finding the polarization (Barkas) correction in the theory of energy losses by charged particles in collisions with multielectron atoms is proposed. The Barkas correction is presented in a simple analytical form. We make comparisons with experimental data and show that applying the Barkas correction improves the agreement between theory and experiment.

  4. Model for Calculating Electrolytic Shunt Path Losses in Large Electrochemical Energy Conversion Systems

    Science.gov (United States)

    Prokopius, P. R.

    1976-01-01

    Generalized analysis and solution techniques were developed to evaluate the shunt power losses in electrochemical systems designed with a common or circulating electrolyte supply. Sample data are presented for a hypothetical bulk energy storage redox system, and the general applicability of the analysis technique is discussed.

  5. Estimation of the energy loss at the blades in rowing: common assumptions revisited

    NARCIS (Netherlands)

    Hofmijster, M.J.; de Koning, J.J.; van Soest, A.J.

    2010-01-01

    In rowing, power is inevitably lost as kinetic energy is imparted to the water during push-off with the blades. Power loss is estimated from reconstructed blade kinetics and kinematics. Traditionally, it is assumed that the oar is completely rigid and that force acts strictly perpendicular to the

  6. STIM with energy loss contrast: An imaging modality unique to MeV ions

    International Nuclear Information System (INIS)

    Lefevre, H.W.; Schofield, R.M.S.; Bench, G.S.; Legge, G.J.F.

    1991-01-01

    Scanning transmission ion microscopy (STIM) through measurement of energy loss of individual ions is a quantitative imaging technique with several unique capabilities. The uniqueness derives conjointly from the large penetration with small scattering of MeV ions in low-Z specimens, from the simple relationship between energy loss and projected or areal density, and from the almost 100% efficiency with which one obtains pixel data from individual ions. Since contrast is in energy loss and not in numbers of events, the statistics of energy loss straggling affects the image but the statistics of counting does not. Small scattering makes it possible to observe details within transparent specimens. High efficiency makes it possible to collect large data sets for computed tomography, stereo, or high-definition imaging with a small radiation dose. High efficiency allows one to minimize aberrations by use of small apertures, to achieve good precision in the determination of areal density, or even to image live biological specimens in air since only one or a few ions per pixel are required. This paper includes a bibliography on STIM with MeV ions, it discusses the accuracy that one can achieve in the areal density coloring of a pixel with data from one or a few ions, and it supplements that review with recent examples from the Melbourne and the Eugene microprobes. (orig.)

  7. A Bench Measurement of the Energy Loss of a Stored Beam to a Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Sands, M; Rees, J.; /SLAC

    2016-12-19

    A rather simple electronic bench experiment is proposed for obtaining a measure of the impulse energy loss of a stored particle bunch to an rf cavity or other vacuum-chamber structure--the so-called "cavity radiation". The proposed method is analyzed in some detail.

  8. On FEL integral equation and electron energy loss in intermediate gain regime

    International Nuclear Information System (INIS)

    Takao, Masaru

    1994-03-01

    The FEL pendulum equation in a intermediate gain small signal regime is investigated. By calculating the energy loss of the electron beam in terms of the solution of the pendulum equation, we confirm the consistency of the FEL equation in intermediate gain regime. (author)

  9. Energy loss and online directional track visualization of fast electrons with the pixel detector Timepix

    Czech Academy of Sciences Publication Activity Database

    Granja, C.; Krist, Pavel; Chvátil, David; Šolc, J.; Pospíšil, S.; Jakubek, J.; Opalka, L.

    2013-01-01

    Roč. 59, DEC (2013), s. 245-261 ISSN 1350-4487 Institutional support: RVO:61389005 Keywords : interaction of radiation with matter * dE/dx detectors * particle tracking detectors * hybrid pixel detectors * active nuclear emulsion * energy loss Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.140, year: 2013

  10. Estimation of the energy loss at the blades in rowing: common assumptions revisited.

    Science.gov (United States)

    Hofmijster, Mathijs; De Koning, Jos; Van Soest, A J

    2010-08-01

    In rowing, power is inevitably lost as kinetic energy is imparted to the water during push-off with the blades. Power loss is estimated from reconstructed blade kinetics and kinematics. Traditionally, it is assumed that the oar is completely rigid and that force acts strictly perpendicular to the blade. The aim of the present study was to evaluate how reconstructed blade kinematics, kinetics, and average power loss are affected by these assumptions. A calibration experiment with instrumented oars and oarlocks was performed to establish relations between measured signals and oar deformation and blade force. Next, an on-water experiment was performed with a single female world-class rower rowing at constant racing pace in an instrumented scull. Blade kinematics, kinetics, and power loss under different assumptions (rigid versus deformable oars; absence or presence of a blade force component parallel to the oar) were reconstructed. Estimated power losses at the blades are 18% higher when parallel blade force is incorporated. Incorporating oar deformation affects reconstructed blade kinematics and instantaneous power loss, but has no effect on estimation of power losses at the blades. Assumptions on oar deformation and blade force direction have implications for the reconstructed blade kinetics and kinematics. Neglecting parallel blade forces leads to a substantial underestimation of power losses at the blades.

  11. Timescale and magnitude of plasma thermal energy loss before and during disruptions in JET

    International Nuclear Information System (INIS)

    Riccardo, V.; Loarte, A.

    2005-01-01

    In this paper we analyse and discuss the thermal energy loss dynamics before and during JET disruptions that occurred between 2002 and 2004 in discharges which reached >4.5 MJ of thermal energy. We observe the slow thermal energy transients with diamagnetic loops and the fast ones with electron cyclotron emission and soft x-ray diagnostics. For most disruption types in JET, the plasma thermal energy at the time of the thermal quench is substantially less than that of the full performance plasma, typically in the range of 10-50% depending on plasma conditions and disruption type. The exceptions to this observation are disruptions in plasmas with a strong internal transport barrier (ITB) and in discharges terminating in a pure vertical displacement event, in which the plasma conserves a very high energy content up to the thermal quench. These disruption types are very sudden, leaving little scope for the combined action of soft plasma landing strategies and intrinsic performance degradation, both requiring >500 ms to be effective, to decrease the available thermal energy. The characteristic time for the loss of energy from the main plasma towards the PFCs in the thermal quench of JET disruptions is in the range 0.05-3.0 ms. The shortest timescales are typical of disruptions caused by excessive pressure peaking in ITB discharges. The available thermal energy fraction and thermal quench duration observed in JET can be processed (with due caution) into estimates for the projected PFC lifetime of the ITER target

  12. Probing medium-induced jet splitting and energy loss in heavy-ion collisions

    Science.gov (United States)

    Chang, Ning-Bo; Cao, Shanshan; Qin, Guang-You

    2018-06-01

    The nuclear modification of jet splitting in relativistic heavy-ion collisions at RHIC and the LHC energies is studied based on the higher twist formalism. Assuming coherent energy loss for the two splitted subjets, a non-monotonic jet energy dependence is found for the nuclear modification of jet splitting function: strongest modification at intermediate jet energies whereas weaker modification for larger or smaller jet energies. Combined with the smaller size and lower density of the QGP medium at RHIC than at the LHC, this helps to understand the groomed jet measurements from CMS and STAR Collaborations: strong modification of the momentum sharing zg distribution at the LHC and no obvious modification of zg distribution at RHIC. In addition, the observed nuclear modification pattern of the groomed jet zg distribution cannot be explained solely by independent energy loss of the two subjets. Our result may be tested in future measurements of groomed jets with lower jet energies at the LHC and larger jet energies at RHIC, for different angular separations between the two subjets.

  13. Impact of stand-by energy losses in electronic devices on smart network performance

    Directory of Open Access Journals (Sweden)

    Mandić-Lukić Jasmina S.

    2012-01-01

    Full Text Available Limited energy resources and environmental concerns due to ever increasing energy consumption, more and more emphasis is being put on energy savings. Smart networks are promoted worldwide as a powerful tool used to improve the energy efficiency through consumption management, as well as to enable the distributed power generation, primarily based on renewable energy sources, to be optimally explored. To make it possible for the smart networks to function, a large number of electronic devices is needed to operate or to be in their stand-by mode. The consumption of these devices is added to the consumption of many other electronic devices already in use in households and offices, thus giving rise to the overall power consumption and threatening to counteract the primary function of smart networks. This paper addresses the consumption of particular electronic devices, with an emphasis placed on their thermal losses when in stand-by mode and their total share in the overall power consumption in certain countries. The thermal losses of electronic devices in their stand-by mode are usually neglected, but it seems theoretically possible that a massive increase in their number can impact net performance of the future smart networks considerably so that above an optimum level of energy savings achieved by their penetration, total consumption begins to increase. Based on the current stand-by energy losses from the existing electronic devices, we propose that the future penetration of smart networks be optimized taking also into account losses from their own electronic devices, required to operate in stand-by mode.

  14. Where do the main losses of energy resources occur - at the point of consumption or at the point of production?

    Energy Technology Data Exchange (ETDEWEB)

    Moskalenko, Alexander

    2010-09-15

    This is an opinion of an independent consultant about key sources of energy losses. It differentiates from the one commonly accepted. The main loser of energy is an energy sector - producers of energy and the distribution networks, responsible for transporting of energy, not the housing and the transportation sector. This opinion is based on the GCE Group's experience. The author proposes to focus the work to reduce energy losses on increasing the energy efficiency of energy sector, not on the end consumer. This will allow to reduce the cost of energy unit production and to reduce greenhouse gas emissions.

  15. Effect of Diet Composition on Energy Expenditure during Weight Loss: The POUNDS LOST Study

    Science.gov (United States)

    Bray, George A.; Smith, Steven R.; DeJonge, Lilian; de Souza, Russell; Rood, Jennifer; Champagne, Catherine M.; Laranjo, Nancy; Carey, Vincent; Obarzanek, Eva; Loria, Catherine M.; Anton, Stephen D.; Ryan, Donna H.; Greenway, Frank L.; Williamson, Donald; Sacks, Frank M.

    2011-01-01

    Background Weight loss reduces energy expenditure, but the contribution of different macronutrients to this change is unclear. Hypothesis We tested the hypothesis that macronutrient composition of the diet might affect the partitioning of energy expenditure during weight loss. Design A sub-study of 99 participants from the POUNDS LOST trial had total energy expenditure (TEE) measured by doubly labeled water and resting energy expenditure (REE) measured by indirect calorimetry at baseline and repeated at 6 months in 89 participants. Participants were randomly assigned to one of 4 diets with either 15% or 25% protein and 20% or 40% fat. Results TEE and REE were positively correlated with each other and with fat free mass and body fat, at baseline and 6 months. The average weight loss of 8.1±0.65 kg (LSmean±SE) reduced TEE by 120±56 kcal/d and REE by 136±18 kcal/d. A greater weight loss at 6 months was associated with a greater decrease in TEE and REE. Participants eating the high fat diet lost significantly more fat free mass (1.52±0.55 kg) than the low fat diet group (p<0.05). Participants eating the low fat diet had significantly higher measures of physical activity than the high fat group. Conclusion A greater weight loss was associated with a larger decrease in both TEE and REE. The low fat diet was associated with significant changes in fat free body mass and energy expenditure from physical activity compared to the high fat diet. PMID:21946707

  16. Optimal Scheduling of Integrated Energy Systems with Combined Heat and Power Generation, Photovoltaic and Energy Storage Considering Battery Lifetime Loss

    Directory of Open Access Journals (Sweden)

    Yongli Wang

    2018-06-01

    Full Text Available Integrated energy systems (IESs are considered a trending solution for the energy crisis and environmental problems. However, the diversity of energy sources and the complexity of the IES have brought challenges to the economic operation of IESs. Aiming at achieving optimal scheduling of components, an IES operation optimization model including photovoltaic, combined heat and power generation system (CHP and battery energy storage is developed in this paper. The goal of the optimization model is to minimize the operation cost under the system constraints. For the optimization process, an optimization principle is conducted, which achieves maximized utilization of photovoltaic by adjusting the controllable units such as energy storage and gas turbine, as well as taking into account the battery lifetime loss. In addition, an integrated energy system project is taken as a research case to validate the effectiveness of the model via the improved differential evolution algorithm (IDEA. The comparison between IDEA and a traditional differential evolution algorithm shows that IDEA could find the optimal solution faster, owing to the double variation differential strategy. The simulation results in three different battery states which show that the battery lifetime loss is an inevitable factor in the optimization model, and the optimized operation cost in 2016 drastically decreased compared with actual operation data.

  17. Study of the radiated energy loss during massive gas injection mitigated disruptions on EAST

    Science.gov (United States)

    Duan, Y. M.; Hao, Z. K.; Hu, L. Q.; Wang, L.; Xu, P.; Xu, L. Q.; Zhuang, H. D.; EAST Team

    2015-08-01

    The MGI mitigated disruption experiments were carried out on EAST with a new fast gas controlling valve in 2012. Different amounts of noble gas He or mixed gas of 99% He + 1% Ar are injected into plasma in current flat-top phase and current ramp-down phase separately. The initial results of MGI experiments are described. The MGI system and the radiation measurement system are briefly introduced. The characteristics of radiation distribution and radiation energy loss are analyzed. About 50% of the stored thermal energy Wdia is dissipated by radiation during the entire disruption process and the impurities of C and Li from the PFC play important roles to radiative energy loss. The amount of the gas can affect the pre-TQ phase. Strong poloidal asymmetry of radiation begins to appear in the CQ phase, which is possibly caused by the plasma configuration changes as a result of VDE. No toroidal radiation asymmetry is observed presently.

  18. Radiative energy losses from a high-current air-blast arc

    International Nuclear Information System (INIS)

    Strachan, D.C.; Lidgate, D.; Jones, G.R.

    1977-01-01

    The importance of total radiation losses from high-current arcs burning in highly accelerated air flows representative of conditions existing in commercial gas-blast switchgear has been investigated. Such losses have been measured both in the high-pressure region upstream of a shaped orifice, where gas velocities are low, and in the region downstream where velocities become supersonic and pressure conditions approach ambient. The dominance of upstream electrode vapor as the source of plasma radiation losses is demonstrated and the importance of radiated losses within the arc energy balance is examined using measured values of axial electric field. For upstream electrodes of elkonite (sintered copper/tungsten) as used in high-power gas-blast circuit breakers, it is shown that some 30--40% of the electrical energy input upstream of the orifice is lost as radiation, while downstream this figure becomes 10--20%. The effect of reservoir pressure on arc electric fields is examined and the contribution to this effect of radiation losses is quantified

  19. Positron annihilation induced Auger electron spectroscopy and its implementation at accelerator based low energy positron factories

    International Nuclear Information System (INIS)

    Weiss, A.; Koeymen, A.R.; Mehl, D.; Lee, K.H.; Yang Gimo; Jensen, K.

    1991-01-01

    Positron annihilation induced auger electron spectroscopy (PAES) makes use of a beam of low energy positrons to excite Auger transitions by annihilating core electrons. The large secondary electron background usually present in Auger spectra can be eliminated by setting the positron beam energy well below the Auger electron energy. This allows true Auger lineshapes to be obtained. Further, because the positron is localized just outside the surface before it annihilates, PAES is extremely sensitive to the topmost atomic layer. Recent PAES results obtained at the University of Texas at Arlington will be presented. In addition, the use of high resolution energy analyzers with multichannel particle detection schemes to prevent problems due to the high data rates associated with accelerator based positron beams will be discussed. (orig.)

  20. Method for optimal design of pipes for low-energy district heating, with focus on heat losses

    DEFF Research Database (Denmark)

    Dalla Rosa, Alessandro; Li, Hongwei; Svendsen, Svend

    2011-01-01

    The synergy between highly energy-efficient buildings and low-energy district heating (DH) systems is a promising concept for the optimal integration of energy-saving policies and energy supply systems based on renewable energy (RE). Network transmission and distribution heat loss is one of the k...

  1. Extended wave-packet model to calculate energy-loss moments of protons in matter

    Science.gov (United States)

    Archubi, C. D.; Arista, N. R.

    2017-12-01

    In this work we introduce modifications to the wave-packet method proposed by Kaneko to calculate the energy-loss moments of a projectile traversing a target which is represented in terms of Gaussian functions for the momentum distributions of electrons in the atomic shells. These modifications are introduced using the Levine and Louie technique to take into account the energy gaps corresponding to the different atomic levels of the target. We use the extended wave-packet model to evaluate the stopping power, the energy straggling, the inverse mean free path, and the ionization cross sections for protons in several targets, obtaining good agreements for all these quantities on an extensive energy range that covers low-, intermediate-, and high-energy regions. The extended wave-packet model proposed here provides a method to calculate in a very straightforward way all the significant terms of the inelastic interaction of light ions with any element of the periodic table.

  2. Design and performance of a spin-polarized electron energy loss spectrometer with high momentum resolution

    Energy Technology Data Exchange (ETDEWEB)

    Vasilyev, D.; Kirschner, J. [Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany)

    2016-08-15

    We describe a new “complete” spin-polarized electron energy loss spectrometer comprising a spin-polarized primary electron source, an imaging electron analyzer, and a spin analyzer of the “spin-polarizing mirror” type. Unlike previous instruments, we have a high momentum resolution of less than 0.04 Å{sup −1}, at an energy resolution of 90-130 meV. Unlike all previous studies which reported rather broad featureless data in both energy and angle dependence, we find richly structured spectra depending sensitively on small changes of the primary energy, the kinetic energy after scattering, and of the angle of incidence. The key factor is the momentum resolution.

  3. Determining the static electronic and vibrational energy correlations via two-dimensional electronic-vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Hui; Lewis, Nicholas H. C.; Oliver, Thomas A. A.; Fleming, Graham R., E-mail: grfleming@lbl.gov [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, Californial 94720 (United States); Kavli Energy NanoSciences Institute at Berkeley, Berkeley, California 94720 (United States)

    2015-05-07

    Changes in the electronic structure of pigments in protein environments and of polar molecules in solution inevitably induce a re-adaption of molecular nuclear structure. Both changes of electronic and vibrational energies can be probed with visible or infrared lasers, such as two-dimensional electronic spectroscopy or vibrational spectroscopy. The extent to which the two changes are correlated remains elusive. The recent demonstration of two-dimensional electronic-vibrational (2DEV) spectroscopy potentially enables a direct measurement of this correlation experimentally. However, it has hitherto been unclear how to characterize the correlation from the spectra. In this paper, we present a theoretical formalism to demonstrate the slope of the nodal line between the excited state absorption and ground state bleach peaks in the spectra as a characterization of the correlation between electronic and vibrational transition energies. We also show the dynamics of the nodal line slope is correlated to the vibrational spectral dynamics. Additionally, we demonstrate the fundamental 2DEV spectral line-shape of a monomer with newly developed response functions.

  4. Investigation of the energy loss and the charge state of high energy heavy ions in a hydrogen plasma

    International Nuclear Information System (INIS)

    Dietrich, K.G.

    1991-07-01

    For heavy ions with energy of 1.4 to 5.9 MeV/u the energy loss and charge state after transmission through a totally ionized hydrogen plasma are investigated. Plasma target was a Z-pinch device incorporated in the beam optics of the accelerator by a pumping system. In the 20 cm long pinch hydrogen plasmas with densities up to 1.5x10 19 cm -3 and temperatures above 5 eV are produced, with ionization efficiency higher than 99%. The ions pass the plasma on the symmetry axis of the plasma column through small apertures in the electrodes. The energy loss was measured by time-of-flight method, the plasma density by interferometry along the pinch axis. For the first time the ion charge after transmission through the plasma has been determined by a charge spectrometer being a combination of a dipole magnet and a position sensitive detector with high time resolution. A growth of the average charge of heavy ions in plasma higher than the equilibrium charge in cold gas was discovered, caused by a reduction of electron capture by fast heavy ions in ionized matter. The electron loss rates in plasma and cold gas are equal. (orig./AH) [de

  5. Integrated simulation of ELM energy loss determined by pedestal MHD and SOL transport

    International Nuclear Information System (INIS)

    Hayashi, N.; Takizuka, T.; Ozeki, T.; Aiba, N.; Oyama, N.

    2007-01-01

    An integrated simulation code TOPICS-IB based on a transport code with a stability code for the peeling-ballooning modes and a scrape-off-layer (SOL) model has been developed to clarify self-consistent effects of edge localized modes (ELMs) and the SOL on the plasma performance. Experimentally observed collisionality dependence of the ELM energy loss is found to be caused by both the edge bootstrap current and the SOL transport. The bootstrap current decreases with an increase in collisionality and intensifies the magnetic shear at the pedestal region. The increase in the magnetic shear reduces the width of eigenfunctions of unstable modes, which results in the reduction of both the area of the ELM enhanced transport and the ELM enhanced transport near the separatrix. On the other hand, when an ELM crash occurs, the energy flows into the SOL and the SOL temperature rapidly increases. The increase in the SOL temperature lowers the ELM energy loss due to the flattening of the radial edge gradient. The parallel electron heat conduction determines how the SOL temperature increases. For higher collisionality, the conduction becomes lower and the SOL electron temperature increases more. By the above two mechanisms, the ELM energy loss decreases with increasing collisionality

  6. Dynamical energy loss as a novel Quark–Gluon Plasma tomographic tool

    Energy Technology Data Exchange (ETDEWEB)

    Djordjevic, Magdalena

    2016-12-15

    High momentum suppression of light and heavy flavor observables is considered to be an excellent probe of jet-medium interactions in QCD matter created at RHIC and LHC. Utilizing this tool requires accurate suppression predictions for different experiments, probes and experimental conditions, and their unbiased comparison with experimental data. With this goal, we developed the dynamical energy loss formalism towards generating predictions for non-central collisions; the formalism takes into account both radiative and collisional energy loss computed within the same theoretical framework, dynamical (as opposed to static) scattering centers, finite magnetic mass, running coupling and uses no free parameters in comparison with experimental data. Within this formalism, we provided predictions, and a systematic comparison with experimental data, for a diverse set of suppression data: all available light and heavy flavor probes, lower and high momentum ranges, various centrality ranges and various collision energies at RHIC and LHC. We here also provide clear qualitative and quantitative predictions for soon to become available LHC experimental data. Comprehensive agreement between our predictions and experimental results provides a good deal of confidence that our dynamical energy loss formalism can well explain the jet-medium interactions in QGP, which will be further tested by the obtained predictions for the upcoming data. Application of this model, as a novel high-precision tomographic tool of QGP medium, are also discussed.

  7. Mitigating energy loss on distribution lines through the allocation of reactors

    Science.gov (United States)

    Miranda, T. M.; Romero, F.; Meffe, A.; Castilho Neto, J.; Abe, L. F. T.; Corradi, F. E.

    2018-03-01

    This paper presents a methodology for automatic reactors allocation on medium voltage distribution lines to reduce energy loss. In Brazil, some feeders are distinguished by their long lengths and very low load, which results in a high influence of the capacitance of the line on the circuit’s performance, requiring compensation through the installation of reactors. The automatic allocation is accomplished using an optimization meta-heuristic called Global Neighbourhood Algorithm. Given a set of reactor models and a circuit, it outputs an optimal solution in terms of reduction of energy loss. The algorithm is also able to verify if the voltage limits determined by the user are not being violated, besides checking for energy quality. The methodology was implemented in a software tool, which can also show the allocation graphically. A simulation with four real feeders is presented in the paper. The obtained results were able to reduce the energy loss significantly, from 50.56%, in the worst case, to 93.10%, in the best case.

  8. Flavors in the Soup: An Overview of Heavy-Flavored Jet Energy Loss at CMS

    CERN Document Server

    Jung, Kurt

    2016-01-01

    Kurt E. Jung PhD, Purdue University, May 2016. Flavors in the Soup: An Overviewof Heavy-Flavored Jet Energy Loss at CMS. Major Professor: Wei Xie.The energy loss of jets in heavy-ion collisions is expected to depend on the flavorof the fragmenting parton. Thus, measurements of jet quenching as a function offlavor place powerful constraints on the thermodynamical and transport propertiesof the hot and dense medium. Measurements of the nuclear modification factorsof the heavy flavor tagged jets from charm and bottom quarks in both PbPb andpPb collisions can quantify such energy loss e↵ects. Specifically, pPb measurementsprovide crucial insights into the behavior of the cold nuclear matter e↵ect, whichis required to fully understand the hot and dense medium e↵ects on jets in PbPbcollisions. This dissertation presents the energy modification of b-jets in PbPb atppsN N = 2.76 TeV and pPb collisions at sN N = 5.02 TeV, along with the first everpmeasurements of charm jets in pPb collisions at sN N = 5.0...

  9. Neutrino energy loss rates due to key iron isotopes for core-collapse physics

    International Nuclear Information System (INIS)

    Nabi, J.-U.

    2008-07-01

    Accurate estimates of neutrino energy loss rates are needed for the study of the late stages of the stellar evolution, in particular for the cooling of neutron stars and white dwarfs. The energy spectra of neutrinos and antineutrinos arriving at the Earth can also provide useful information on the primary neutrino fluxes as well as neutrino mixing scenario. Proton-neutron quasi-particle random phase approximation (pn-QRPA) theory has recently being used for a microscopic calculation of stellar weak interaction rates of fp-shell nuclide, particularly iron isotopes, with success. Here I present the calculation of neutrino and antineutrino energy loss rates due to key iron isotopes in stellar matter using the pn-QRPA theory. The rates are calculated on a fine grid of temperature-density scale suitable for core-collapse simulators. The calculated rates are compared against earlier calculations. The neutrino cooling rates due to even-even isotopes of iron, 54,56 Fe, are in good agreement with the rates calculated using the large-scale shell model. The pn-QRPA calculated neutrino energy loss rates due to 55 Fe are enhanced roughly around an order of magnitude compared to the large-scale shell model calculation during the oxygen and silicon shell burning stages of massive stars and favor a lower entropy for the cores of massive stars. (author)

  10. Issues in characterizing resting energy expenditure in obesity and after weight loss

    Directory of Open Access Journals (Sweden)

    Anja eBosy-Westphal

    2013-03-01

    Full Text Available Normalization of resting energy expenditure (REE for body composition using the 2-compartment model (fat mass, FM and fat-free mass, FFM has inherent limitations for the interpretation of REE and may lead to erroneous conclusions when comparing people with a wide range of adiposity as well as before and after substantial weight loss. We compared different methods of REE normalization: (i for FFM and FM (ii by the inclusion of %FM as a measure of adiposity and (iii based on organ and tissue masses. Results were compared between healthy subjects with different degrees of adiposity as well as within subject before and after weight loss. Normalizing REE from an REE vs. FFM and FM equation that (i was derived in obese participants and applied to lean people or (ii was derived before weight loss and applied after weight loss leads to the erroneous conclusion of a lower metabolic rate (i in lean persons and (ii after weight loss. This is revealed by the normalization of REE for organ and tissue masses that was not significantly different between lean and obese or between baseline and after weight loss. There is evidence for an increasing specific metabolic rate of FFM with increasing %FM that could be explained by a higher contribution of liver, kidney and heart mass to FFM in obesity. Using REE vs. FFM and FM equations specific for different levels of adiposity (% fat mass eliminated differences in REE before and after weight loss in women. In conclusion, the most established method for normalization of REE based on FFM and FM may lead to spurious conclusions about metabolic rate in obesity and the phenomenon of weight loss-associated adaptive thermogenesis. Using % fat mass-specific REE prediction from FFM and FM in kg may improve the normalization of REE when subjects with wide differences in % fat mass are investigated.

  11. Energy resolved electrochemical impedance spectroscopy for electronic structure mapping in organic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Nádaždy, V., E-mail: nadazdy@savba.sk; Gmucová, K. [Institute of Physics SAS, Dúbravská cesta 9, 845 11 Bratislava (Slovakia); Schauer, F. [Faculty of Education, Trnava University in Trnava, 918 43 Trnava (Slovakia); Faculty of Applied Informatics, Tomas Bata University in Zlin, 760 05 Zlin (Czech Republic)

    2014-10-06

    We introduce an energy resolved electrochemical impedance spectroscopy method to map the electronic density of states (DOS) in organic semiconductor materials. The method consists in measurement of the charge transfer resistance of a semiconductor/electrolyte interface at a frequency where the redox reactions determine the real component of the impedance. The charge transfer resistance value provides direct information about the electronic DOS at the energy given by the electrochemical potential of the electrolyte, which can be adjusted using an external voltage. A simple theory for experimental data evaluation is proposed, along with an explanation of the corresponding experimental conditions. The method allows mapping over unprecedentedly wide energy and DOS ranges. Also, important DOS parameters can be determined directly from the raw experimental data without the lengthy analysis required in other techniques. The potential of the proposed method is illustrated by tracing weak bond defect states induced by ultraviolet treatment above the highest occupied molecular orbital in a prototypical σ-conjugated polymer, poly[methyl(phenyl)silylene]. The results agree well with those of our previous DOS reconstruction by post-transient space-charge-limited-current spectroscopy, which was, however, limited to a narrow energy range. In addition, good agreement of the DOS values measured on two common π-conjugated organic polymer semiconductors, polyphenylene vinylene and poly(3-hexylthiophene), with the rather rare previously published data demonstrate the accuracy of the proposed method.

  12. Measurement of {alpha} particle energy loss in biological tissue below 2 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Stella, S. [Department of Nuclear and Theoretical Physics, University of Pavia, Pavia (Italy); National Institute of Nuclear Physics (INFN), Pavia (Italy); Bortolussi, S. [Department of Nuclear and Theoretical Physics, University of Pavia, Pavia (Italy); National Institute of Nuclear Physics (INFN), Pavia (Italy)], E-mail: silva.bortolussi@pv.infn.it; Bruschi, P.; Portella, C. [Department of Nuclear and Theoretical Physics, University of Pavia, Pavia (Italy); Altieri, S. [Department of Nuclear and Theoretical Physics, University of Pavia, Pavia (Italy); National Institute of Nuclear Physics (INFN), Pavia (Italy)

    2009-09-01

    The energy loss of {alpha} particles crossing biological tissue at energies between 0.8 and 2.2 MeV has been measured. This energy range is very important for boron neutron capture therapy, based on the {sup 10}B(n,{alpha}){sup 7}Li reaction, which emits {alpha} particles with energies of 1.78 and 1.47 MeV. One of the methods used for the measurement of the boron concentration in tissue is based on the deconvolution of the {alpha} spectra obtained from neutron irradiation of thin (70 {mu}m) tissue samples. For this technique, a knowledge of the behaviour of the energy loss of the particles in the irradiated tissue is of critical importance. In particular, the curve of the residual energy as a function of the distance travelled in the tissue must be known. In this paper, the results of an experiment carried out with an {sup 241}Am source and a series of cryostatic sections of rat-lung tissue are presented. The experimental measurements are compared with the results of Monte Carlo calculations performed with the MCNPX code.

  13. Effect of energetic ion loss on ICRF heating efficiency and energy confinement time in heliotrons

    International Nuclear Information System (INIS)

    Murakami, S.; Nakajima, N.; Okamoto, M.; Nuehrenberg, J.

    1999-01-01

    The ICRF heating efficiency and the global energy confinement time during ICRF heating are investigated, including the effect of energetic ion loss in heliotrons. The approximate formula of ICRF heating efficiency is derived using results based on Monte Carlo simulations (Murakami, S., et al., Fusion Eng. Des. 26 (1995) 209). The global energy confinement time including the energetic ion effect can be expressed in heliotrons in terms of ICRF heating power, plasma density and magnetic field strength. Results in plasmas at CHS show a systematic decrease of the global energy confinement time due to energetic ion loss from the assumed energy confinement scaling law, which is consistent with the experimental observations. The model is also applied to ICRF minority heating in LHD plasmas in two cases of typical magnetic configurations. A clear increase of the global energy confinement time due to the stored energy of energetic tail ions is obtained in the 'orbit improved' configuration, while a decrease is observed in the 'standard' configuration. (author)

  14. Measurement of the energy loss of heavy ions in laser-produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Knobloch-Maas, Renate

    2009-11-25

    The interaction of ions with plasma is not yet fully understood today, although it is important for inertial fusion technology. During recent years, the energy loss of heavy ions in plasma has therefore been a subject of research in the Laser and Plasma Physics group of Darmstadt University of Technology. Several experiments were carried out at the Gesellschaft fuer Schwerionenforschung (GSI) in Darmstadt using laser-created plasma, thereby taking advantage of the unique combination of GSI's accelerator facility and the laser system nhelix, which is also described in this work. The experiments focus on the measurement of the energy loss of medium heavy ions in a plasma created by directly heating a thin carbon foil with the nhelix laser, at an energy of about 50 J. In order to measure the energy loss using a time-of-flight method, a stop detector is used to register the arrival of the ion pulses after passing the plasma and a 12 m drift space. At the beginning of the work on this thesis, the ion detector types formerly used were found to be inadequately suited to the difficult task; this was changed during this thesis. The ion detector has to be able to temporarily resolve ion pulses with a frequency of 108 MHz and a width (FWHM) of 3 ns at a very low current. It also has to withstand the X-ray burst from the plasma with a dead time shorter than the difference between the X-ray and the ion time of flight between the plasma and the detector. In order to satisfy these and other demands, a new diamond detector was designed and has now been used for several measurements. In addition to the new detector, other improvements were made concerning the diagnostics and the laser. The laser-created plasma now reaches a maximum temperature exceeding 200 eV and a free electron density of up to 10{sup 22} cm{sup -3}. With this greatly improved setup, energy loss data could be obtained with a temporal resolution several times better than before, using an ion beam with a

  15. Measurement of the energy loss of heavy ions in laser-produced plasmas

    International Nuclear Information System (INIS)

    Knobloch-Maas, Renate

    2009-01-01

    The interaction of ions with plasma is not yet fully understood today, although it is important for inertial fusion technology. During recent years, the energy loss of heavy ions in plasma has therefore been a subject of research in the Laser and Plasma Physics group of Darmstadt University of Technology. Several experiments were carried out at the Gesellschaft fuer Schwerionenforschung (GSI) in Darmstadt using laser-created plasma, thereby taking advantage of the unique combination of GSI's accelerator facility and the laser system nhelix, which is also described in this work. The experiments focus on the measurement of the energy loss of medium heavy ions in a plasma created by directly heating a thin carbon foil with the nhelix laser, at an energy of about 50 J. In order to measure the energy loss using a time-of-flight method, a stop detector is used to register the arrival of the ion pulses after passing the plasma and a 12 m drift space. At the beginning of the work on this thesis, the ion detector types formerly used were found to be inadequately suited to the difficult task; this was changed during this thesis. The ion detector has to be able to temporarily resolve ion pulses with a frequency of 108 MHz and a width (FWHM) of 3 ns at a very low current. It also has to withstand the X-ray burst from the plasma with a dead time shorter than the difference between the X-ray and the ion time of flight between the plasma and the detector. In order to satisfy these and other demands, a new diamond detector was designed and has now been used for several measurements. In addition to the new detector, other improvements were made concerning the diagnostics and the laser. The laser-created plasma now reaches a maximum temperature exceeding 200 eV and a free electron density of up to 10 22 cm -3 . With this greatly improved setup, energy loss data could be obtained with a temporal resolution several times better than before, using an ion beam with a diameter of only

  16. Plasmonic nanoengineering in hollow metal nanostructures: an electron energy-loss spectroscopy study

    OpenAIRE

    Genç, Aziz; Universitat Autònoma de Barcelona. Departament de Física

    2015-01-01

    Resumen en Español Las nanoestructuras metálicas están siendo objeto de gran atención dada su capacidad para generar resonancias plasmónicas, que son oscilaciones colectivas de electrones alojados en la banda de conducción en un metal excitado por efecto de un campo electromagnético. El creciente interés entorno a las nanoestructuras metálicas como fuentes de plasmones, ha resultado en el desarrollo de un nuevo campo, la plasmónica, definida como la ciencia y tecnología de la generación, cont...

  17. Investigation of energy losses in low-coercivity resin-bonded magnets in alternating magnetic fields

    Science.gov (United States)

    Milov, E. V.; Sipin, I. A.; Milov, V. N.; Andreenko, A. S.; Balan, I. A.

    2017-01-01

    Energy losses during alternating remagnetization of low-coercitivity resin-bonded magnets and commercially produced electrical steels were studied experimentally. The studies were conducted on several samples of resin-bonded magnets with different manufacturing technologies and samples of electrical steel sheets of various thicknesses. The static and dynamic magnetic properties of the samples were measured on a vibration magnetometer and a specially designed apparatus, respectively. It was found that the studied samples of bonded magnets have a relatively high level of hysteresis losses associated with high coercivity, which reaches a value of 4-5 Oe. At the same time, the remagnetization losses due to the Foucault currents in the bonded magnets are considerably lower than in electrical steels. The measurement results show that bonded magnets at high frequencies of remagnetization, especially in high-rpm motors, can be competitive in comparison with electrical steels.

  18. Energy losses in the D0 β solenoid cryostat caused by current changes

    International Nuclear Information System (INIS)

    Visser, A.T.

    1993-11-01

    The proposed D0 β solenoid is a superconducting solenoid mounted inside an aluminum tube which supports the solenoid winding over it's full length. This aluminum support tube, also called bobbin, is therefore very tightly coupled to magnetic flux changes caused by solenoid current variations. These current changes in the solenoid, will cause answer currents to flow in the resistive bobbin wall and therefore cause heat losses. The insertion of an external dump resistor in the solenoid current loop reduces energy dissipation inside the cryostat during a quench and will shorten the discharge time constant. This note presents a simple electrical model for the coupled bobbin and solenoid and makes it easier to understand the circuit behavior and losses. Estimates for the maximum allowable rate of solenoid current changes, based on the maximum permissible rate of losses can be made using this model

  19. Exergy losses of resource recovery from a waste-to-energy plant

    DEFF Research Database (Denmark)

    Vyzinkarova, Dana; Laner, D.; Astrup, Thomas Fruergaard

    2013-01-01

    Metal resources recovered from waste incineration bottom ash (BA) are of lower quality as compared to primary resources, but to date no framework for expressing the quality losses exists. Exergy is a concept that may have the potential to evaluate the resource quality in waste management....... In this study, focusing on recovery from waste-to-energy plants with basic and advanced BA treatment, the goal is to give an indication about quality of selected recovered resources (Fe, Al, and Cu) by means of exergy analysis. Metal flows are modeled through both incineration scenarios, and then chemical....... The results indicate that exergy losses due to mixing are insignificant as compared to chemical exergies of metals in all flows. Total exergy losses for Fe, Al, and Cu recovery in the two WtE systems range from 38% to 90%....

  20. N-losses and energy use in a scenario for conversion to organic farming

    DEFF Research Database (Denmark)

    Dalgaard, Tommy; Kjeldsen, Chris; Hutchings, Nick

    2002-01-01

    is not straightforward, and different scenarios for conversion to organic farming might lead to reduced or increased N-losses and E-use. This paper presents a scenario tool that uses a Geographical Information System in association with models for crop rotations, fertilisation practices, N-losses, and E...... reduction at the 95% level. We therefore recommend further research in how conversion to organic farming or other changes in the agricultural practice might help to reduce N-surpluses and E-uses. In that context, the presented scenario tool would be useful......The aims of organic farming include the recycling of nutrients and organic matter and the minimisation of the environmental impact of agriculture. Reduced nitrogen (N)-losses and energy (E)-use are therefore fundamental objectives of conversion to organic farming. However, the case...

  1. Determining the phonon energy of highly oriented pyrolytic graphite by scanning tunneling microscope light emission spectroscopy

    Science.gov (United States)

    Uehara, Yoichi; Michimata, Junichi; Watanabe, Shota; Katano, Satoshi; Inaoka, Takeshi

    2018-03-01

    We have investigated the scanning tunneling microscope (STM) light emission spectra of isolated single Ag nanoparticles lying on highly oriented pyrolytic graphite (HOPG). The STM light emission spectra exhibited two types of spectral structures (step-like and periodic). Comparisons of the observed structures and theoretical predictions indicate that the phonon energy of the ZO mode of HOPG [M. Mohr et al., Phys. Rev. B 76, 035439 (2007)] can be determined from the energy difference between the cutoff of STM light emission and the step in the former structure, and from the period of the latter structure. Since the role of the Ag nanoparticles does not depend on the substrate materials, this method will enable the phonon energies of various materials to be measured by STM light emission spectroscopy. The spatial resolution is comparable to the lateral size of the individual Ag nanoparticles (that is, a few nm).

  2. Energy conservation attenuates the loss of skeletal muscle excitability during intense contractions

    DEFF Research Database (Denmark)

    Macdonald, W A; Ørtenblad, N; Nielsen, Ole Bækgaard

    2007-01-01

    High-frequency stimulation of skeletal muscle has long been associated with ionic perturbations, resulting in the loss of membrane excitability, which may prevent action potential propagation and result in skeletal muscle fatigue. Associated with intense skeletal muscle contractions are large...... with control muscles, the resting metabolites ATP, phosphocreatine, creatine, and lactate, as well as the resting muscle excitability as measured by M-waves, were unaffected by treatment with BTS plus dantrolene. Following 20 or 30 s of continuous 60-Hz stimulation, BTS-plus-dantrolene-treated muscles showed...... changes in muscle metabolites. However, the role of metabolites in the loss of muscle excitability is not clear. The metabolic state of isolated rat extensor digitorum longus muscles at 30 degrees C was manipulated by decreasing energy expenditure and thereby allowed investigation of the effects of energy...

  3. Energy loss of carbon transmitted 1-MeV H2+ ions

    International Nuclear Information System (INIS)

    Fritz, M.; Kimura, K.; Susuki, Y.; Mannami, M.

    1994-01-01

    Energy losses of 1-MeV H 2 + ions passing through carbon foils of 2-8 μg/cm 2 thickness have been measured and show besides the linear increase with target thickness a 0.4 keV offset. The stopping power derived from the observed energy losses is 1.15 times as large as the sum of the stopping powers for two single H + of the same velocity. Calculations of the stopping powers for H 2 + ions and diprotons, using first Born approximation, indicate that the H 2 + ions lose the binding electron upon entrance into the foil, traverse the target as diprotons and recapture target electrons at the exit surface, a scenario also supported by the 0.4 keV offset at zero thickness. (author)

  4. Interplay between bulk medium evolution and (D)GLV energy loss

    International Nuclear Information System (INIS)

    Molnar, Denes; Sun, Deke

    2014-01-01

    We study the consistency between high-p T nuclear suppression (R AA ) and elliptic flow (v 2 ) using Gyulassy–Levai–Vitev (GLV) energy loss or a simpler power-law dE/dL formula, for a variety of bulk evolution models. The results generally confirm our earlier work [1] that found suppressed elliptic flow for transversely expanding media. One exception is the set of hydrodynamic solutions used recently [2] by Betz and Gyulassy, which give significantly higher v 2 but unfortunately assume unrealistic bag-model equation of state. On the other hand, we show that covariant treatment of energy loss introduces an interplay between jet direction and hydrodynamic flow of the medium, which largely counteracts elliptic flow suppression caused by transverse expansion

  5. Cooling equilibrium and beam loss with internal targets in high energy storage rings

    International Nuclear Information System (INIS)

    Boine-Frankenheim, O.; Hasse, R.; Hinterberger, F.; Lehrach, A.; Zenkevich, P.

    2006-01-01

    The beam cooling equilibrium with internal target interaction is analyzed for parameters relevant to the proposed High Energy Storage Ring (HESR). For the proposed experiments with anti-protons high luminosities together with low momentum spreads are required. Rate equations are used to predict the rms equilibrium beam parameters. The cooling and IBS rate coefficients are obtained from simplified models. Energy loss straggling in the target and the associated beam loss are analyzed analytically assuming a thin target. A longitudinal kinetic simulation code is used to study the evolution of the momentum distribution in coasting and bunched beams. Analytic expressions for the target induced momentum tail are found in good agreement with the simulation results

  6. MHD activity and energy loss during beta saturation and collapse at high beta poloidal in PBX

    International Nuclear Information System (INIS)

    Kugel, H.W.; Sesnic, S.; Bol, K.

    1987-10-01

    High-β experiments, in medium to high-q tokamak plasmas, exhibit a temporal β saturation and collapse. This behavior has been attributed to ballooning, ideal kink, or tearing modes. In PBX, a unique diagnostic capability allowed studies of the relation between MHD and energy loss for neutral-beam-heated (<6 MW), mildly indented (10 to 15%), nearly steady I/sub p/ discharges that approached the Troyon-Gruber limit. Under these conditions, correlations between MHD activity and energy losses have shown that the latter can be almost fully accounted for by various long wavelength MHD instabilities and that there is no need to invoke high-n ballooning modes in PBX. 6 refs., 4 figs

  7. Defect production and subsequent effects induced by electronic energy loss of swift heavy ion

    International Nuclear Information System (INIS)

    Hou Mingdong; Liu Jie; Sun Youmei; Yin Jingmin; Yao Huijun; Duan Jinglai; Mo Dan; Zhang Ling; Chen Yanfeng; Chinese Academy of Sciences, Beijing

    2008-01-01

    Swift heavy ion in matter is one of forfront fields of nuclear physics in the world. A series of new phenomena were discovered in recent years. The history and sta- tus on the development of this field were reviewed. Electronic energy loss effects induced by swift heavy ion irradiation, such as defect production and evolution, ion latent track formation, phase transformation and anisotropy plastic deformation were introduced emphatically. A trend of future investigation was explored. (authors)

  8. Energy loss of 107Ag, 109Ag and 150Sm in Ni and Au

    International Nuclear Information System (INIS)

    Ribas, R.V.; Seale, W.A.; Roney, W.M.; Szanto, E.M.

    1979-01-01

    The stopping power of 107 Ag, 109 Ag and 150 Sm in nickel and gold was measured as a preliminary test of a new technique for measuring energy loss based on the γ-ray Dopppler shift. The analysis of the data was based on the theories of Lindhard, Scharff and Schiott for nuclear and electronic stopping. The results are compared with the semi-empirical predictions of Northcliffe and Schilling. (author) [pt

  9. Independent component analysis: A new possibility for analysing series of electron energy loss spectra

    International Nuclear Information System (INIS)

    Bonnet, Nogl; Nuzillard, Danielle

    2005-01-01

    A complementary approach is proposed for analysing series of electron energy-loss spectra that can be recorded with the spectrum-line technique, across an interface for instance. This approach, called blind source separation (BSS) or independent component analysis (ICA), complements two existing methods: the spatial difference approach and multivariate statistical analysis. The principle of the technique is presented and illustrations are given through one simulated example and one real example

  10. Fuzzy-TLBO optimal reactive power control variables planning for energy loss minimization

    International Nuclear Information System (INIS)

    Moghadam, Ahmad; Seifi, Ali Reza

    2014-01-01

    Highlights: • A new approach to the problem of optimal reactive power control variables planning is proposed. • The energy loss minimization problem has been formulated by modeling the load of system as a Load Duration Curve. • To solving the energy loss problem, the classic methods and the evolutionary methods are used. • A new proposed fuzzy teaching–learning based algorithm is applied to energy loss problem. • Simulations are done to show the effectiveness and superiority of the proposed algorithm compared with other methods. - Abstract: This paper offers a new approach to the problem of optimal reactive power control variables planning (ORPVCP). The basic idea is division of Load Duration Curve (LDC) into several time intervals with constant active power demand in each interval and then solving the energy loss minimization (ELM) problem to obtain an optimal initial set of control variables of the system so that is valid for all time intervals and can be used as an initial operating condition of the system. In this paper, the ELM problem has been solved by the linear programming (LP) and fuzzy linear programming (Fuzzy-LP) and evolutionary algorithms i.e. MHBMO and TLBO and the results are compared with the proposed Fuzzy-TLBO method. In the proposed method both objective function and constraints are evaluated by membership functions. The inequality constraints are embedded into the fitness function by the membership function of the fuzzy decision and the problem is modeled by fuzzy set theory. The proposed Fuzzy-TLBO method is performed on the IEEE 30 bus test system by considering two different LDC; and it is shown that using this method has further minimized objective function than original TLBO and other optimization techniques and confirms its potential to solve the ORPCVP problem with considering ELM as the objective function

  11. Effect of inelastic energy losses on development of atom-atom collision cascades

    International Nuclear Information System (INIS)

    Marinyuk, V.V.; Remizovich, V.S.

    2001-01-01

    The problem of influence of inelastic energy losses (ionization braking) of particles on the development of atom-atom collision cascades in infinite medium was studied theoretically. Main attention was paid to study of angular and energy distributions of primary ions and cascade atoms in the presence of braking. Analytical calculations were made in the assumption that single scattering of particles occurs by solid balls law, while the value of electron braking ability of a medium is determined by the Lindhard formula. It is shown that account of braking (directly when solving the Boltzmann transport equation) changes in principle the previously obtained angular and energy spectra of ions and cascade atoms. Moreover, it is the braking that is the determining factor responsible for anisotropy of angular distributions of low-energy primary ions and cascade atoms [ru

  12. Novel Molecules Regulating Energy Homeostasis: Physiology and Regulation by Macronutrient Intake and Weight Loss

    Directory of Open Access Journals (Sweden)

    Anna Gavrieli

    2016-09-01

    Full Text Available Excess energy intake, without a compensatory increase of energy expenditure, leads to obesity. Several molecules are involved in energy homeostasis regulation and new ones are being discovered constantly. Appetite regulating hormones such as ghrelin, peptide tyrosine-tyrosine and amylin or incretins such as the gastric inhibitory polypeptide have been studied extensively while other molecules such as fibroblast growth factor 21, chemerin, irisin, secreted frizzle-related protein-4, total bile acids, and heme oxygenase-1 have been linked to energy homeostasis regulation more recently and the specific role of each one of them has not been fully elucidated. This mini review focuses on the above mentioned molecules and discusses them in relation to their regulation by the macronutrient composition of the diet as well as diet-induced weight loss.

  13. Time-dependent density functional calculation of the energy loss of antiprotons colliding with metallic nanoshells

    International Nuclear Information System (INIS)

    Quijada, M.; Borisov, A.G.; Muino, R.D.

    2008-01-01

    Time-dependent density functional theory is used to study the interaction between antiprotons and metallic nanoshells. The ground state electronic properties of the nanoshell are obtained in the jellium approximation. The energy lost by the antiproton during the collision is calculated and compared to that suffered by antiprotons traveling in metal clusters. The resulting energy loss per unit path length of material in thin nanoshells is larger than the corresponding quantity for clusters. It is shown that the collision process can be interpreted as the antiproton crossing of two nearly bi-dimensional independent metallic systems. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Coherent Radiative Parton Energy Loss beyond the BDMPS-Z Limit

    CERN Document Server

    Zapp, Korinna C

    2012-01-01

    It is widely accepted that a phenomenologically viable theory of jet quenching for heavy ion collisions requires the understanding of medium-induced parton energy loss beyond the limit of eikonal kinematics formulated by Baier-Dokshitzer-Mueller-Peigne-Schiff and Zakharov (BDMPS-Z). Here, we supplement a recently developed exact Monte Carlo implementation of the BDMPS-Z formalism with elementary physical requirements including exact energy-momentum conservation, a refined formulation of jet-medium interactions and a treatment of all parton branchings on the same footing. We document the changes induced by these physical requirements and we describe their kinematic origin.

  15. CMOS circuits for piezoelectric energy harvesters efficient power extraction, interface modeling and loss analysis

    CERN Document Server

    Hehn, Thorsten

    2014-01-01

    This book deals with the challenge of exploiting ambient vibrational energy which can be used to power small and low-power electronic devices, e.g. wireless sensor nodes. Generally, particularly for low voltage amplitudes, low-loss rectification is required to achieve high conversion efficiency. In the special case of piezoelectric energy harvesting, pulsed charge extraction has the potential to extract more power compared to a single rectifier. For this purpose, a fully autonomous CMOS integrated interface circuit for piezoelectric generators which fulfills these requirements is presented.Due

  16. Determination of the area density and composition of alloy film using dual alpha particle energy loss

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xiaojun, E-mail: maxj802@163.com [Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Li, Bo; Gao, Dangzhong [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Xu, Jiayun [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Tang, Yongjian [Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)

    2017-02-01

    A novel method based on dual α-particles energy loss (DAEL) is proposed for measuring the area density and composition of binary alloy films. In order to obtain a dual-energy α-particles source, an ingenious design that utilizes the transmitted α-particles traveling the thin film as a new α-particles source is presented. Using the DAEL technique, the area density and composition of Au/Cu film are determined accurately with an uncertainty of better than 10%. Finally, some measures for improving the combined uncertainty are discussed.

  17. Optoelectronic insights into the photovoltaic losses from photocurrent, voltage, and energy perspectives

    Science.gov (United States)

    Shang, Aixue; An, Yidan; Ma, Dong; Li, Xiaofeng

    2017-08-01

    Photocurrent and voltage losses are the fundamental limitations for improving the efficiency of photovoltaic devices. It is indeed that a comprehensive and quantitative differentiation of the performance degradation in solar cells will promote the understanding of photovoltaic physics as well as provide a useful guidance to design highly-efficient and cost-effective solar cells. Based on optoelectronic simulation that addresses electromagnetic and carrier-transport responses in a coupled finite-element method, we report a detailed quantitative analysis of photocurrent and voltage losses in solar cells. We not only concentrate on the wavelength-dependent photocurrent loss, but also quantify the variations of photocurrent and operating voltage under different forward electrical biases. Further, the device output power and power losses due to carrier recombination, thermalization, Joule heat, and Peltier heat are studied through the optoelectronic simulation. The deep insight into the gains and losses of the photocurrent, voltage, and energy will contribute to the accurate clarifications of the performance degradation of photovoltaic devices, enabling a better control of the photovoltaic behaviors for high performance.

  18. Angular dispersion and energy loss of H+ and He+ in metals

    International Nuclear Information System (INIS)

    Cantero, Esteban

    2006-01-01

    In this master thesis the effects produced when a light ion beam traverses a thin metallic film were studied.In particular, the interactions of low energy (E ≤ 10 keV) light ions (H + ,H 2 + , D + , He + ) with monocrystalline and also polycrystalline gold samples were investigated.In first place, the dependence of the stopping power with projectiles' velocity was studied, analyzing the threshold effect in the excitation of the 5d electrons in the channelling regime for energies between 0,4 and 9 keV.Next, the angular dispersion of ions in polycrystalline and monocrystalline films was measured and analyzed.Comparisons for different energies and projectiles were done, studying molecular and isotopic effects.Using Lindhard's channeling theory, a scale law for the angular dispersion of angles greater than the critical angle was found.Additionally, the angular dependence of the energy loss and the energy loss straggling of protons transmitted through monocrystals were measured.To explain the angular variations of these magnitudes a theoretical model based on the electronic density fluctuations inside the channel was developed [es

  19. Evaluation of Losses Of Cold Energy of Cryogen Products in The Transport Systems

    Science.gov (United States)

    Uglanov, Dmitry; Sarmin, Dmitry; Tsapkova, Alexandra; Burdina, Yana

    2017-12-01

    At present, there are problems of energy saving in various areas of human life and in power complexes of industrial plants. One possible solution to the problem of increasing energy efficiency is the use of liquefied natural gas and its cold energy. Pipelines for fuel or gas supply in cryogen supply systems have different length depending on the mutual position of storage and cryogen consumption devices relatively to a start construction. Cryogen supply and transport systems include a lot of fittings of different assortment. Reservoirs can be installed on different elevation points. To reduce heat inleak and decrease cold energy of cryogen product different kinds of thermal insulation are used. Cryogen pipelines provide required operation conditions of storage and gasifying systems. The aim of the thermal calculation of cryogen transport and supply systems is to define the value of cryogen heat. In this paper it is shown values of cryogen temperature rise due to heat inleaks at cryogen’s transfer along transport systems for ethane, methane, oxygen and nitrogen were calculated. Heat inleaks also due to hydraulic losses were calculated. Specific losses of cold energy of cryogen product for laminar and turbulent flow were calculated. Correspondences of temperature rise, critical pipeline’s length and Reynolds number were defined for nitrogen, argon, methane and oxygen.

  20. A precise measurement of 180 GeV muon energy losses in iron

    CERN Document Server

    Amaral, P; Anderson, K; Artikov, A; Benetta, R; Berglund, S R; Biscarat, C; Blanch, O; Blanchot, G; Bogush, A A; Bohm, C; Boldea, V; Borisov, O N; Bosman, M; Bromberg, C; Bravo, S; Budagov, Yu A; Burdin, S V; Calôba, L P; Camarena, F; Carvalho, J; Castillo, M V; Cavalli-Sforza, M; Cavasinni, V; Cerqueira, A S; Chadelas, R; Chirikov-Zorin, I E; Chlachidze, G; Cobal, M; Cogswell, F; Cologna, S; Constantinescu, S; Costanzo, D; Cowan, Brian; Crouau, M; Daudon, F; David, M; Davidek, T; Dawson, J; De, K; Delfino, M C; Del Prete, T; De Santo, A; Di Girolamo, B; Dita, S; Downing, R; Engström, M; Errede, D; Errede, S; Fassi, F; Fenyuk, A; Ferrer, A; Flaminio, Vincenzo; Flix, J; Garabik, R; Gil, I; Gildemeister, O; Glagoley, V; Gómez, A; González de la Hoz, S; Grabskii, V; Grenier, P; Hakopian, H H; Haney, M; Hellman, S; Henriques, A; Hébrard, C; Higón, E; Holik, P; Holmgren, S O; Hruska, I; Huston, J; Jon-And, K; Kakurin, S; Karyukhin, A N; Khubua, J I; Kopikov, S V; Krivkova, P; Kukhtin, V V; Kulchitskii, Yu A; Kuzmin, M V; Lami, S; Lapin, V; Lazzeroni, C; Lebedev, A; Leitner, R; Li, J; Lomakin, Yu F; Lomakina, O V; Lokajícek, M; López-Amengual, J M; Maio, A; Malyukov, S N; Marroquin, F; Mataix, L; Mazzoni, E; Merritt, F S; Miller, R; Minashvili, I A; Miralles, L; Montarou, G; Némécek, S; Nessi, Marzio; Onofre, A; Ostankov, A P; Pacheco, A; Pallin, D; Pantea, D; Paoletti, R; Park, I C; Pilcher, J E; Pinhão, J; Price, L; Proudfoot, J; Pukhov, O; Reinmuth, G; Renzoni, G; Richards, R; Roda, C; Roldán, J; Romance, J B; Romanov, V; Rosnet, P; Ruiz, H; Rusakovitch, N A; Sanchis, E; Sanders, H; Santoni, C; Santo, J; Says, L P; Seixas, J M; Selldén, B; Semenov, A A; Shcelchkov, A; Shochet, M J; Silva, J; Simaitis, V J; Sissakian, A N; Solodkov, A A; Solovyanov, O; Sosebee, M; Soustruznik, K; Spanó, F; Stanek, R; Starchenko, E A; Stavina, O P; Suk, M; Sykora, I; Tang, F; Tas, P; Thaler, J J; Thome-Filho, Z D; Tokar, S; Topilin, N D; Valklar, S; Varanda, M J; Vartapetian, A H; Vazeille, F; Vichou, I; Vinogradov, V; Vorozhtsov, S B; White, A; Wolters, H; Yamdagni, N; Yarygin, G; Yosef, C; Zaitsev, A

    2001-01-01

    The energy loss spectrum of 180 GeV muons has been measured with the 5.6 m long finely segmented Module 0 of the ATLAS hadron tile calorimeter at the CERN SPS. The differential probability dP/d nu per radiation length of a fractional energy loss nu = Delta E/sub mu //E /sub mu / has been measured in the range 0.025energy losses due to bremsstrahlung, production of electron-positron pairs, and energetic knock-on electrons. The iron elastic form factor correction Delta /sub Fe//sup el/=1.63+or-0.17/sub stat/+or-023/sub syst$/ -/sub 0.14 //sup +0.20//sub theor/ to muon bremsstrahlung in the region of no screening of the nucleus by atomic electrons has been measured for the first time, and is compared with different theoretical predictions. (31 refs).

  1. Radiation losses and global energy balance for Ohmically heated discharges in ASDEX

    International Nuclear Information System (INIS)

    Mueller, E.R.; Behringer, K.; Niedermeyer, H.

    1982-01-01

    Global energy balance, radiation profiles and dominant impurity radiation sources are compared for Ohmically heated limiter and divertor discharges in the ASDEX tokamak. In discharges with a poloidal stainless-steel limiter, total radiation from the plasma is the dominant energy loss channel. The axisymmetric divertor reduces this volume-integrated radiation to 30-35% of the heating power and additional Ti-gettering halves it again to 10-15%. Local radiation losses in the plasma centre, which are mainly due to the presence of iron impurity ions, are reduced by about one order of magnitude. In high-current (Isub(p) = 400 kA) and high-density (nsub(e)-bar = 6 x 10 13 cm -3 ) ungettered divertor discharges, up to 55% of the heating power is dumped into a cold-gas target inside the divertor chambers. The bolometrically detected volume power losses in the chambers can mainly be attributed to neutral hydrogen atoms with kinetic energies of a few eV. In this parameter range, the divertor plasma is dominated by inelastic molecular and atomic processes, the main process being Franck-Condon dissociation of H 2 molecules. (author)

  2. Energy loss of a high charge bunched electron beam in plasma: Simulations, scaling, and accelerating wakefields

    Directory of Open Access Journals (Sweden)

    J. B. Rosenzweig

    2004-06-01

    Full Text Available The energy loss and gain of a beam in the nonlinear, “blowout” regime of the plasma wakefield accelerator, which features ultrahigh accelerating fields, linear transverse focusing forces, and nonlinear plasma motion, has been asserted, through previous observations in simulations, to scale linearly with beam charge. Additionally, from a recent analysis by Barov et al., it has been concluded that for an infinitesimally short beam, the energy loss is indeed predicted to scale linearly with beam charge for arbitrarily large beam charge. This scaling is predicted to hold despite the onset of a relativistic, nonlinear response by the plasma, when the number of beam particles occupying a cubic plasma skin depth exceeds that of plasma electrons within the same volume. This paper is intended to explore the deviations from linear energy loss using 2D particle-in-cell simulations that arise in the case of experimentally relevant finite length beams. The peak accelerating field in the plasma wave excited behind the finite-length beam is also examined, with the artifact of wave spiking adding to the apparent persistence of linear scaling of the peak field amplitude into the nonlinear regime. At large enough normalized charge, the linear scaling of both decelerating and accelerating fields collapses, with serious consequences for plasma wave excitation efficiency. Using the results of parametric particle-in-cell studies, the implications of these results for observing severe deviations from linear scaling in present and planned experiments are discussed.

  3. Spectroscopy and energy level location of the trivalent lanthanides in LiYP4O12

    International Nuclear Information System (INIS)

    Dorenbos, P.; Shalapska, T.; Stryganyuk, G.; Gektin, A.; Voloshinovskii, A.

    2011-01-01

    The excitation and emission properties of the lanthanides Ce 3+ , Pr 3+ , Nd 3+ , Sm 3+ , Eu 3+ , Tb 3+ , Er 3+ , Tm 3+ , and Yb 3+ in LiYP 4 O 12 were studied by vacuum ultra-violet spectroscopy at 10 K. It provides information on the energies of 4f-5d excitation and emission bands. In the case of Er 3+ spin forbidden emission was observed. Charge transfer excitation bands were identified for Eu 3+ , Sm 3+ , Tm 3+ , and Yb 3+ , and in the case of Yb 3+ charge transfer luminescence is observed. All data appear to be consistent with each other and have been used to construct a level scheme showing the location of the energy levels of all trivalent and divalent lanthanides in LiYP 4 O 12 . - Research Highlights: → The spectroscopy of most of the trivalent lanthanides in LiYP 4 O 12 is presented for the first time. → Charge transfer luminescence of Yb3+ is reported. → We demonstrate that the energy of the first 4f-5d transition and the charge transfer band agree with predictive models. → For the first time a scheme with the location of all lanthanide states (divalent and trivalent ) w.r.t. de-valence and conduction band of LIP 4 O 12 is presented.

  4. 31P-magnetic resonance spectroscopy: Impaired energy metabolism in latent hyperthyroidism

    International Nuclear Information System (INIS)

    Theissen, P.; Kaldewey, S.; Moka, D.; Bunke, J.; Voth, E.; Schicha, H.

    1993-01-01

    31 Phosphorous magnetic resonance spectroscopy allows an in vivo examination of energy metabolism. The present study was designed to evaluate whether in patients with latent hyperthyroidism alterations of muscle energy metabolism could be found similar to those observed in patients with overt hyperthyroidism. In 10 patients with overt hyperthyroidism before therapy and 20 with latent hyperthyroidism (also without therapy) and in 24 healthy volunteers magnetic resonance spectroscopy of the calf muscle was performed within a 1.5-Tesla magnet. Muscle concentrations of phosphocreatine, inorganic phosphate, and ATP were quantified compared to an external standard solution of K 2 HPO 4 . In the patients with overt hyperthyroidism and with latent hyperthyroidism a significant decrease of phosphocreatine was found. Further, the ATP concentration in patients with latent and manifest hyperthyroidism tended towards lower values. There were no significant differences in the decrease of phosphocreatine and ATP between both patient groups. Therefore, this study for the first time shows that alterations of energy metabolism in latent hyperthyroidism can be measured and that they are similar to those observed in overt hyperthyroidism. (orig.) [de

  5. THREE-PHASE ENERGY SUPPLY SYSTEMS SIMULATION FOR THE TOTAL POWER LOSSES COMPONENTS ASSESSMENT

    Directory of Open Access Journals (Sweden)

    D.V. Tugay

    2016-09-01

    Full Text Available Purpose. The goal is to optimize a structure of Matlab-model of the three-phase energy supply system with power active filter. The mathematical model that describes the energy supply system modes of operation which contains additional losses is proposed. Methodology. We have applied concepts of the electrical circuits theory, mathematical modeling elements based on linear algebra and vector calculus, mathematical simulation in Matlab package. Results. We have developed two models of three-phase energy supply system. The first one is based on a vector representation, and the second one on the matrix representation of energy processes. Using these models we have solved the problem of maintaining unchanged the average useful power for 279 cases of energy supply system modes of operation. Originality. We have developed methods of mathematical analysis of a three-phase energy supply systems with polyharmonic voltages and currents in the symmetric and asymmetric modes. Practical value. We have created Matlab-model of a three-phase energy supply system with automated calculation of a correction factor. It allows reducing more than one order the time for energy processes elucidation in multiphase systems.

  6. Energy-momentum density of graphite by electron-momentum spectroscopy

    International Nuclear Information System (INIS)

    Vos, M.; Fang, Z.; Canney, S.; Kheifets, A.; McCarthy, I.E.; Weigold, E.

    1996-11-01

    The energy-resolved electron momentum density of graphite has been measured along a series of well-defined directions using electron momentum spectroscopy (EMS). This is the first measurement of this kind performed on a single-crystal target with a thoroughly controlled orientation which clearly demonstrates the different nature of the σ and π bands in graphite. Good agreement between the calculated density and the measured one is found, further establishing that fact that EMS yields more direct and complete information on the valence electronic structure that any other method. 12 refs., 2 figs

  7. Energy consumption of audiovisual devices in the residential sector: Economic impact of harmonic losses

    International Nuclear Information System (INIS)

    Santiago, I.; López-Rodríguez, M.A.; Gil-de-Castro, A.; Moreno-Munoz, A.; Luna-Rodríguez, J.J.

    2013-01-01

    In this work, energy losses and the economic consequences of the use of small appliances containing power electronics (PE) in the Spanish residential sector were estimated. Audiovisual devices emit harmonics, originating in the distribution system an increment in wiring losses and a greater demand in the total apparent power. Time Use Surveys (2009–10) conducted by the National Statistical Institute in Spain were used to obtain information about the activities occurring in Spanish homes regarding the use of audiovisual equipment. Moreover, measurements of different types of household appliances available in the PANDA database were also utilized, and the active and non-active annual power demand of these residential-sector devices were determined. Although a single audiovisual device has an almost negligible contribution, the aggregated actions of this type of appliances, whose total annual energy demand is greater than 4000 GWh, can be significant enough to be taken into account in any energy efficiency program. It was proven that a reduction in the total harmonic distortion in the distribution systems ranging from 50% to 5% can reduce energy losses significantly, with economic savings of around several million Euros. - Highlights: • Time Use Survey provides information about Spanish household electricity consumption. • The annual aggregated energy demand of audiovisual appliances is very significant. • TV use accounts for more than 80% of household audiovisual electricity consumption. • A reduction from 50% to 5% in the total harmonic distortion would have economic savings of around several million Euros. • Stricter regulations regarding harmonic emissions must be demanded

  8. A method for measurements of neutral fragments kinetic energies released to a specific dissociation threshold: optical translational spectroscopy

    International Nuclear Information System (INIS)

    Roney, A.; Frigon, C.; Larzilliere, M.

    1999-01-01

    The optical translational spectroscopy technique, based on the principles of fast ion beam laser spectroscopy (FIBLAS) and translational spectroscopy, allows the kinetic energies study of neutral fragments released through free dissociation of a neutral molecule. This method presents interesting features such as near-threshold energy measurements and selection of a specific dissociation limit. The fragments resulting from free dissociation (not induced) of neutral molecules, produced by charge exchange processes with a fast ion beam, are probed by laser radiation. Monitoring of the laser-induced fluorescence allows high-resolution spectra due to the kinematic compression of the velocity spread. Measurements of kinetic energies released to the second limit of dissociation H(1s) + H(2l) of H 2 are put forth and compared with those obtained by means of off-axis translational spectroscopy

  9. Considering linear generator copper losses on model predictive control for a point absorber wave energy converter

    International Nuclear Information System (INIS)

    Montoya Andrade, Dan-El; Villa Jaén, Antonio de la; García Santana, Agustín

    2014-01-01

    Highlights: • We considered the linear generator copper losses in the proposed MPC strategy. • We maximized the power transferred to the generator side power converter. • The proposed MPC increases the useful average power injected into the grid. • The stress level of the PTO system can be reduced by the proposed MPC. - Abstract: The amount of energy that a wave energy converter can extract depends strongly on the control strategy applied to the power take-off system. It is well known that, ideally, the reactive control allows for maximum energy extraction from waves. However, the reactive control is intrinsically noncausal in practice and requires some kind of causal approach to be applied. Moreover, this strategy does not consider physical constraints and this could be a problem because the system could achieve unacceptable dynamic values. These, and other control techniques have focused on the wave energy extraction problem in order to maximize the energy absorbed by the power take-off device without considering the possible losses in intermediate devices. In this sense, a reactive control that considers the linear generator copper losses has been recently proposed to increase the useful power injected into the grid. Among the control techniques that have emerged recently, the model predictive control represents a promising strategy. This approach performs an optimization process on a time prediction horizon incorporating dynamic constraints associated with the physical features of the power take-off system. This paper proposes a model predictive control technique that considers the copper losses in the control optimization process of point absorbers with direct drive linear generators. This proposal makes the most of reactive control as it considers the copper losses, and it makes the most of the model predictive control, as it considers the system constraints. This means that the useful power transferred from the linear generator to the power

  10. Effects of diet composition on postprandial energy availability during weight loss maintenance.

    Directory of Open Access Journals (Sweden)

    Carolyn O Walsh

    Full Text Available The major circulating metabolic fuels regulate hunger, and each is affected by dietary composition. An integrated measure of postprandial energy availability from circulating metabolic fuels may help inform dietary recommendations for weight maintenance after weight loss.We examined the effect of low-fat (LF, 60% of energy from carbohydrate, 20% fat, 20% protein, low-glycemic index (LGI, 40%-40%-20%, and very low-carbohydrate (VLC, 10%-60%-30% diets on total postprandial metabolic fuel energy availability (EA during weight loss maintenance.Eight obese young adults were fed a standard hypocaloric diet to produce 10-15% weight loss. They were then provided isocaloric LF, LGI, and VLC diets in a randomized crossover design, each for a 4-week period of weight loss maintenance. At the end of each dietary period, a test meal representing the respective diet was provided, and blood samples were obtained every 30 minutes for 5 hours. The primary outcome was EA, defined as the combined energy density (circulating level × relative energy content of glucose, free fatty acids, and β-hydroxybutyrate. Secondary outcomes were individual metabolic fuels, metabolic rate, insulin, glucagon, cortisol, epinephrine, and hunger ratings. Respiratory quotient was a process measure. Data were analyzed by repeated-measures analysis of variance, with outcomes compared in the early (30 to 150 min and late (180 to 300 min postprandial periods.EA did not differ between the test meals during the early postprandial period (p = 0.99. However, EA in the late postprandial period was significantly lower after the LF test meal than the LGI (p<0.0001 and VLC (p<0.0001 test meals. Metabolic rate also differed in the late postprandial period (p = 0.0074, with higher values on the VLC than LF (p = 0.0064 and LGI (p = 0.0066 diets.These findings suggest that an LF diet may adversely affect postprandial EA and risk for weight regain during weight loss maintenance.

  11. Precise measurements of energy loss straggling for swift heavy ions in polymers

    Energy Technology Data Exchange (ETDEWEB)

    Rani, Bindu [Department of Physics, Kurukshetra University, Kurukshetra 136 119 (India); Neetu [Department of Physics, S.D College, Panipat 132103 (India); Sharma, Kalpana [Department of Physics, CMR Institute of Technology, Bangalore 560037 (India); Diwan, P.K. [Department of Applied Sciences, UIET, Kurukshetra University, Kurukshetra 136 119 (India); Kumar, Shyam, E-mail: profshyam@gmail.com [Department of Physics, Kurukshetra University, Kurukshetra 136 119 (India)

    2016-11-15

    The energy loss straggling measurements for heavy ions with Z = 3–22 (∼0.2–2.5 MeV/u) in PEN (C{sub 7}H{sub 5}O{sub 2}) and PET (C{sub 10}H{sub 8}O{sub 4}) polymers have been carried out utilizing the swift heavy ion beam facility from 15UD Pelletron accelerator at Inter University Accelerator Centre (IUAC), New Delhi, India. The recorded spectra are analyzed in such a way that the Straggling associated with energy loss process could be measured in a systematic manner at any selected value of energy, in terms of per unit thickness of the absorber, at any desired energy intervals. The measured values have been compared with the calculated values obtained from the most commonly used Bethe-Livingston formulations applicable for collisional straggling. The results are tried to be understood in terms of the effective charge on the impinging ion within the absorber. Some interesting trends are observed.

  12. Experimental and theoretical study of the energy loss of C and O in Zn

    Energy Technology Data Exchange (ETDEWEB)

    Cantero, E. D.; Lantschner, G. H.; Arista, N. R. [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, 8400 San Carlos de Bariloche (Argentina); Montanari, C. C.; Miraglia, J. E. [Instituto de Astronomia y Fisica del Espacio (CONICET-UBA), Buenos Aires (Argentina); Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires (Argentina); Behar, M.; Fadanelli, R. C. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, Porto Alegre-RS (Brazil)

    2011-07-15

    We present a combined experimental-theoretical study of the energy loss of C and O ions in Zn in the energy range 50-1000 keV/amu. This contribution has a double purpose, experimental and theoretical. On the experimental side, we present stopping power measurements that fill a gap in the literature for these projectile-target combinations and cover an extended energy range, including the stopping maximum. On the theoretical side, we make a quantitative test on the applicability of various theoretical approaches to calculate the energy loss of heavy swift ions in solids. The description is performed using different models for valence and inner-shell electrons: a nonperturbative scattering calculation based on the transport cross section formalism to describe the Zn valence electron contribution, and two different models for the inner-shell contribution: the shellwise local plasma approximation (SLPA) and the convolution approximation for swift particles (CasP). The experimental results indicate that C is the limit for the applicability of the SLPA approach, which previously was successfully applied to projectiles from H to B. We find that this model clearly overestimates the stopping data for O ions. The origin of these discrepancies is related to the perturbative approximation involved in the SLPA. This shortcoming has been solved by using the nonperturbative CasP results to describe the inner-shell contribution, which yields a very good agreement with the experiments for both C and O ions.

  13. Heavy quark energy loss far from equilibrium in a strongly coupled collision

    CERN Document Server

    Chesler, Paul M; Rajagopal, Krishna

    2013-01-01

    We compute and study the drag force acting on a heavy quark propagating through the matter produced in the collision of two sheets of energy in a strongly coupled gauge theory that can be analyzed holographically. Although this matter is initially far from equilibrium, we find that the equilibrium expression for heavy quark energy loss in a homogeneous strongly coupled plasma with the same instantaneous energy density or pressure as that at the location of the quark describes many qualitative features of our results. One interesting exception is that there is a time delay after the initial collision before the heavy quark energy loss becomes significant. At later times, once a liquid plasma described by viscous hydrodynamics has formed, expressions based upon assuming instantaneous homogeneity and equilibrium provide a semi-quantitative description of our results - as long as the rapidity of the heavy quark is not too large. For a heavy quark with large rapidity, the gradients in the velocity of the hydrodyna...

  14. X-ray spectroscopy studies of nonradiative energy transfer processes in luminescent lanthanide materials

    Science.gov (United States)

    Pacold, Joseph I.

    Luminescent materials play important roles in energy sciences, through solid state lighting and possible applications in solar energy utilization, and in biomedical research and applications, such as in immunoassays and fluorescence microscopy. The initial excitation of a luminescent material leads to a sequence of transitions between excited states, ideally ending with the emission of one or more optical-wavelength photons. It is essential to understand the microscopic physics of this excited state cascade in order to rationally design materials with high quantum efficiencies or with other fine-tuning of materials response. While optical-wavelength spectroscopies have unraveled many details of the energy transfer pathways in luminescent materials, significant questions remain open for many lanthanide-based luminescent materials. For organometallic dyes in particular, quantum yields remain limited in comparison with inorganic phosphors. This dissertation reports on a research program of synchrotron x-ray studies of the excited state electronic structure and energy-relaxation cascade in trivalent lanthanide phosphors and dyes. To this end, one of the primary results presented here is the first time-resolved x-ray absorption near edge spectroscopy studies of the transient 4f excited states in lanthanide-activated luminescent dyes and phosphors. This is a new application of time-resolved x-ray absorption spectroscopy that makes it possible to directly observe and, to some extent, quantify intramolecular nonradiative energy transfer processes. We find a transient increase in 4f spectral weight associated with an excited state confined to the 4f shell of trivalent Eu. This result implies that it is necessary to revise the current theoretical understanding of 4f excitation in trivalent lanthanide activators: either transient 4f-5d mixing effects are much stronger than previously considered, or else the lanthanide 4f excited state has an unexpectedly large contribution

  15. Note: Microelectrode-shielding tip for scanning probe electron energy spectroscopy

    Science.gov (United States)

    Huang, Wei; Li, Zhean; Xu, Chunkai; Liu, Jian; Xu, Chunye; Chen, Xiangjun

    2018-04-01

    We report a novel microelectrode-shielding tip (ME tip) for scanning probe electron energy spectroscopy (SPEES). The shielding effect of this tip is studied through comparing the detection efficiency with the normal tip by both experiment and simulation. The results show that the backscattering count rate detected by the SPEES instrument using the normal tip begins to decrease as the tip approaches to the sample surface within 21 μm, while that using the ME tip only starts to drop off within 1 μm. This indicates that the electron energy spectra can be measured with the ME tip at a much closer tip-sample distance. Furthermore, it is also demonstrated that the ME tip can be used to obtain topography of the sample surface in situ simultaneously.

  16. Influence of experimental conditions on atom column visibility in energy dispersive X-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dycus, J.H.; Xu, W.; Sang, X. [Department of Materials Science and Engineering, North Carolina State University, 911 Partners Way Engineering Building 1, Raleigh, NC 27606 (United States); D' Alfonso, A.J. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Chen, Z. [School of Physics and Astronomy, Monash University, Clayton, Victoria 3800 (Australia); Weyland, M. [Monash Centre for Electron Microscopy, Monash University, Clayton, Victoria 3800 (Australia); Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800 (Australia); Allen, L.J. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Findlay, S.D. [School of Physics and Astronomy, Monash University, Clayton, Victoria 3800 (Australia); LeBeau, J.M., E-mail: jmlebeau@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, 911 Partners Way Engineering Building 1, Raleigh, NC 27606 (United States)

    2016-12-15

    Here we report the influence of key experimental parameters on atomically resolved energy dispersive X-ray spectroscopy (EDX). In particular, we examine the role of the probe forming convergence semi-angle, sample thickness, lattice spacing, and dwell/collection time. We show that an optimum specimen-dependent probe forming convergence angle exists to maximize the signal-to-noise ratio of the atomically resolved signal in EDX mapping. Furthermore, we highlight that it can be important to select an appropriate dwell time to efficiently process the X-ray signal. These practical considerations provide insight for experimental parameters in atomic resolution energy dispersive X-ray analysis. - Highlights: • Impacts of microscope operating conditions on EDX signal and atom column contrast are demonstrated. • Influence of sample thickness and lattice spacing is shown. • Conditions for obtaining optimal signal and contrast for different sample types are discussed. • Effects of dwell time during EDX acquisition are discussed.

  17. A generalized muon trajectory estimation algorithm with energy loss for application to muon tomography

    Science.gov (United States)

    Chatzidakis, Stylianos; Liu, Zhengzhi; Hayward, Jason P.; Scaglione, John M.

    2018-03-01

    This work presents a generalized muon trajectory estimation algorithm to estimate the path of a muon in either uniform or nonuniform media. The use of cosmic ray muons in nuclear nonproliferation and safeguard verification applications has recently gained attention due to the non-intrusive and passive nature of the inspection, penetrating capabilities, as well as recent advances in detectors that measure position and direction of the individual muons before and after traversing the imaged object. However, muon image reconstruction techniques are limited in resolution due to low muon flux and the effects of multiple Coulomb scattering (MCS). Current reconstruction algorithms, e.g., point of closest approach (PoCA) or straight-line path (SLP), rely on overly simple assumptions for muon path estimation through the imaged object. For robust muon tomography, efficient and flexible physics-based algorithms are needed to model the MCS process and accurately estimate the most probable trajectory of a muon as it traverses an object. In the present work, the use of a Bayesian framework and a Gaussian approximation of MCS is explored for estimation of the most likely path of a cosmic ray muon traversing uniform or nonuniform media and undergoing MCS. The algorithm's precision is compared to Monte Carlo simulated muon trajectories. It was found that the algorithm is expected to be able to predict muon tracks to less than 1.5 mm root mean square (RMS) for 0.5 GeV muons and 0.25 mm RMS for 3 GeV muons, a 50% improvement compared to SLP and 15% improvement when compared to PoCA. Further, a 30% increase in useful muon flux was observed relative to PoCA. Muon track prediction improved for higher muon energies or smaller penetration depth where energy loss is not significant. The effect of energy loss due to ionization is investigated, and a linear energy loss relation that is easy to use is proposed.

  18. Energy transmittance predicts conductive hearing loss in older children and adults

    Science.gov (United States)

    Keefe, Douglas H.; Simmons, Jeffrey L.

    2003-12-01

    The test performance of a wideband acoustic transfer function (ATF) test and 226-Hz tympanometry was assessed in predicting the presence of conductive hearing loss, based on an air-bone gap of 20 dB or more. Two ATF tests were designed using an improved calibration method over a frequency range (0.25-8 kHz): an ambient-pressure test and a tympanometric test using an excess static pressure in the ear canal. Wideband responses were objectively classified using moment analyses of energy transmittance, which was a more appropriate test variable than energy reflectance. Subjects included adults and children of age 10 years and up, with 42 normal-functioning ears and 18 ears with a conductive hearing loss. Predictors were based on the magnitudes of the moment deviations from the 10th to 90th percentiles of the normal group. Comparing tests at a fixed specificity of 0.90, the sensitivities were 0.28 for peak-compensated static acoustic admittance at 226 Hz, 0.72 for ambient-pressure ATF, and 0.94 for pressurized ATF. Pressurized ATF was accurate at predicting conductive hearing loss with an area under the receiver operating characteristic curve of 0.95. Ambient-pressure ATF may have sufficient accuracy to use in some hearing-screening applications, whereas pressurized ATF has additional accuracy that may be appropriate for hearing-diagnostic applications.

  19. Photoemission spectroscopy study on interfacial energy level alignments in tandem organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Ou, Qing-Dong; Li, Chi; Li, Yan-Qing, E-mail: yqli@suda.edu.cn; Tang, Jian-Xin, E-mail: jxtang@suda.edu.cn

    2015-10-01

    Highlights: • The interface energetics of tandem OLEDs is overviewed. • Energy level alignment in CGLs is addressed via photoemission spectroscopy. • The n-type doping effect with cesium compounds is discussed. • Hole injection barrier is dependent on oxygen vacancies in transition metal oxides. • Device lifetime of tandem OLEDs is sensitive to interfacial stability of CGLs. - Abstract: Organic light-emitting diodes (OLEDs) using a tandem structure offer a highly attractive option for the applications of next-generation flat panel displays and solid-state lighting due to the extremely high brightness and efficiency along with the long operational lifetime. In general, reliable information about interface energetics of the charge generation layers (CGLs), which plays the central role in charge generation and carrier injection into the stacked emission units, is highly desirable and advantageous for interface engineering and the performance optimization of tandem OLEDs. In this review, our recent studies on tandem OLEDs are overviewed, especially from interface energetics perspective via photoemission spectroscopy. The electronic structures of various transition metal oxide (TMO)-based CGLs and their role in charge generation process are reviewed, addressing the n-type doping impact of organic layers in CGLs, thermal annealing-induced oxygen vacancy in TMOs, and the interfacial stability of CGLs on the device operational lifetime. The resulting energy level alignments are summarized in correspondence with tandem OLED performance.

  20. Energy-momentum structure of the krypton valence shell by electron-momentum spectroscopy

    International Nuclear Information System (INIS)

    Nicholson, R.; Braidwood, S.W.; McCathy, I.E.; Weigold, E.; Brunger, M.J.

    1996-03-01

    Momentum distributions and spectroscopic factors are obtained in a high resolution electron-momentum spectroscopy study of krypton at 1000 eV. The shapes and relative magnitudes of the momentum profiles are in good agreement with the results of calculations made within the distorted-wave impulse approximation (DWIA) framework. The DWIA describes the relative magnitudes of the 4p and 4s manifolds as well as giving a good representation of the shapes of the respective 4p and 4s cross sections. Results for the momentum profiles belonging to excited 2 P o and 2 S e manifolds are also presented. Spectroscopic factors for transitions belonging to the 2 p o and 2 S e manifolds are assigned up to a binding energy of 42 eV. The spectroscopic factor for the lowest 4s transition is 0.51 ± 0.01, whereas that for the ground-state 4p transition is 0.98± 0.01. Comparisons of the present binding energies and spectroscopic factors are made against the results of several many-body calculations and photoelectron spectroscopy (PES) results. In addition, a new procedure is outlined, utilising the experimental 4p and 4s manifold cross sections, that provides information on possible initial state configuration interaction effects in krypton. 50 refs., 2 tabs., 10 figs

  1. LASER SPECTROSCOPY AND TRACE ELEMENT ANALYSIS Chapter from the Energy and Environment Division Annual Report 1980

    Energy Technology Data Exchange (ETDEWEB)

    Various, Authors

    1981-05-01

    In order to control pollutants resulting from energy production and utilization, adequate methods are required for monitoring the level of various substances often present at low concentrations. The Energy and Environment Division Applied Research in Laser Spectroscopy & Analytical Techniques Program is directed toward meeting these needs, Emphasis is on the development of physical methods, as opposed to conventional chemical analysis techniques. The advantages, now widely recognized, include ultra-high sensitivity coupled with minimal sample preparation. In some instances physical methods provide multi-parameter measurements which often provide the only means of achiev·ing the sensitivity necessary for the detection of trace contaminants. Work is reported in these areas: APPLIED PHYSICS AND LASER SPECTROSCOPY RESEARCH; MICROPROCESSOR CONTROLLER ANODIC STRIPPING VOLTAMETER FOR TRACE METALS ANALYSIS IN WATER; THE SURVEY OF INSTRUMENTATION FOR ENVIRONMENTAL MONITORING; THE POSSIBLE CHRONDRITIC NATURE OF THE DANISH CRETACEOUS~TERTIARY BOUNDARY; IMPROVEMENT OF THE SENSITIVITY AND PRECISION OF NEUTRON ACTIVATION ANALYSIS OF SOME ELEMENTS IN PLANKTON AND PLANKTONIC FISH; and SOURCES OF SOME SECONDARILY WORKED OBSIDIAN ARTIFACTS FROM TIKAL, GUATEMALA.

  2. Energy calibration issues in nuclear resonant vibrational spectroscopy: observing small spectral shifts and making fast calibrations.

    Science.gov (United States)

    Wang, Hongxin; Yoda, Yoshitaka; Dong, Weibing; Huang, Songping D

    2013-09-01

    The conventional energy calibration for nuclear resonant vibrational spectroscopy (NRVS) is usually long. Meanwhile, taking NRVS samples out of the cryostat increases the chance of sample damage, which makes it impossible to carry out an energy calibration during one NRVS measurement. In this study, by manipulating the 14.4 keV beam through the main measurement chamber without moving out the NRVS sample, two alternative calibration procedures have been proposed and established: (i) an in situ calibration procedure, which measures the main NRVS sample at stage A and the calibration sample at stage B simultaneously, and calibrates the energies for observing extremely small spectral shifts; for example, the 0.3 meV energy shift between the 100%-(57)Fe-enriched [Fe4S4Cl4](=) and 10%-(57)Fe and 90%-(54)Fe labeled [Fe4S4Cl4](=) has been well resolved; (ii) a quick-switching energy calibration procedure, which reduces each calibration time from 3-4 h to about 30 min. Although the quick-switching calibration is not in situ, it is suitable for normal NRVS measurements.

  3. Energy utilization, carbon dioxide emission, and exergy loss in flavored yogurt production process

    International Nuclear Information System (INIS)

    Sorgüven, Esra; Özilgen, Mustafa

    2012-01-01

    This paper investigates the impact of food production processes on the environment in terms of energy and exergy utilization and carbon dioxide emission. There are three different energy utilization mechanisms in food production: Utilization of solar energy by plants to produce agricultural goods; feed consumption by herbivores to produce meat and milk; fossil fuel consumption by industrial processes to perform mixing, cooling, heating, etc. Production of strawberry-flavored yogurt, which involves these three mechanisms, is investigated here thermodynamically. Analysis starts with the cultivation of the ingredients and ends with the transfer of the final product to the market. The results show that 53% of the total exergy loss occurs during the milk production and 80% of the total work input is consumed during the plain yogurt making. The cumulative degree of perfection is 3.6% for the strawberry-flavored yogurt. This value can rise up to 4.6%, if renewable energy resources like hydropower and algal biodiesel are employed instead of fossil fuels. This paper points the direction for the development of new technology in food processing to decrease waste of energy and carbon dioxide accumulation in the atmosphere. -- Highlights: ► Energy and exergy utilization and carbon dioxide emission during strawberry-flavored yogurt production. ► Cumulative degree of perfection of strawberry-flavored yogurt is 3.6%. ► 53% of the total exergy loss occurs during the milk production. ► 80% of the total work input is consumed during the plain yogurt making.

  4. DETERMINATION OF ENERGY LOSSES BY SHOCK ABSORBER IN A FREIGHT CAR AT CRASH MODE

    Directory of Open Access Journals (Sweden)

    Ya. V. Bolzhelarskyi

    2016-08-01

    Full Text Available Purpose. The purpose of this work is to determine the energy losses in the shock absorber of the freight car whose wheel-set moves in the derailed state on the track panel depending on the axle load and structural parameters of spring suspension. Methodology. On the basis of spring suspension construction analysis and operating principle of the friction shock absorber of the freight car bogie the authors provide the method for determining the energy absorbed by it. The calculations take the maximum values of the absorber elements displacement and the regulatory values of spring suspension parameters. Findings. The authors obtained the calculated formula for determining the energy absorbed by shock absorber for regulation-set mounting schemes of elastic bogie elements depending on the axial load. The mentioned curves are parabolic. Originality. The work examines the crash mode of the wheel-set movement on the track panels after its derailment. It is shown that the energy dissipation in the shock absorbers is the reason for increase in resistance to rolling stock movement. The formulas for calculating the amount of energy dissipated in the shock absorber with a maximum displacement of its elements are derived. This energy depends on the axle load and structural parameters of spring suspension. Practical value. The proposed method allows setting the value of the additional resistance to motion that occurs in crash mode which makes it possible to increase the accuracy of traction calculations.

  5. Critical rate of energy loss for registration of charged particles in cellulose nitrate

    International Nuclear Information System (INIS)

    Knoefel, T.M.J.; Sachett, I.A.

    1979-09-01

    Cellulose nitrate films LR-115 type II (Kodak-Pathe) have been exposed, at right angles, to alpha-particle beams in the energy range 2.5 - 5.5 MeV. From measurements of both through etched track density, a critical rate of energy lo ss for track registration of (0.85 +- 0.05) MeV cm 2 /mg has been derived, which corresponds to a critical alpha-particle energy of (4.6 +- 0.4) MeV. These results are compatible with those obtained by other authors whenever similar etching conditions are used. The concepts of threshold rate of energy loss and a threshold energy for etched-track formation are introduced, and their values are obtained from the experiment as being (0.80 +- 0.05) MeV cm 2 /mg and (5.1 +- 0.4) Mev, respectively. In addition, the present work provides a suitable set of useful, reference data for further applications of such plastic nuclear track detector in problems concerned with the detection of low-energy alpha particles. (Author) [pt

  6. Surface effects in the energy loss of ions passing through a thin foil

    International Nuclear Information System (INIS)

    Osma, J.; Garcia de Abajo, F.J.

    1997-01-01

    The role of surface plasmon excitation in the interaction of ions passing through thin films has been studied in both the Bloch hydrodynamic approximation and the local response approach for projectile velocities above the maximum of the stopping power curve. The effect of the surface is found to be much weaker when the dispersion of the modes is taken into consideration than in the case of nondispersive media, though qualitatively the main features of the hydrodynamic approach resemble those of the local one. A generalization of the Bothe-Landau convolution formula for the loss probability distribution is derived to take into account the scattering due to the surface. The effects of the surface in the energy-loss spectra are discussed. A comparison with experiment is given. copyright 1997 The American Physical Society

  7. Optimized high energy resolution in γ-ray spectroscopy with AGATA triple cluster detectors

    Energy Technology Data Exchange (ETDEWEB)

    Wiens, Andreas

    2011-06-20

    The AGATA demonstrator consists of five AGATA Triple Cluster (ATC) detectors. Each triple cluster detector contains three asymmetric, 36-fold segmented, encapsulated high purity germanium detectors. The purpose of the demonstrator is to show the feasibility of position-dependent γ-ray detection by means of γ-ray tracking, which is based on pulse shape analysis. The thesis describes the first optimization procedure of the first triple cluster detectors. Here, a high signal quality is mandatory for the energy resolution and the pulse shape analysis. The signal quality was optimized and the energy resolution was improved through the modification of the electronic properties, of the grounding scheme of the detector in particular. The first part of the work was the successful installation of the first four triple cluster detectors at INFN (National Institute of Nuclear Physics) in Legnaro, Italy, in the demonstrator frame prior to the AGATA commissioning experiments and the first physics campaign. The four ATC detectors combine 444 high resolution spectroscopy channels. This number combined with a high density were achieved for the first time for in-beam γ-ray spectroscopy experiments. The high quality of the ATC detectors is characterized by the average energy resolutions achieved for the segments of each crystal in the range of 1.943 and 2.131 keV at a γ-ray energy of 1.33 MeV for the first 12 crystals. The crosstalk level between individual detectors in the ATC is negligible. The crosstalk within one crystal is at a level of 10{sup -3}. In the second part of the work new methods for enhanced energy resolution in highly segmented and position sensitive detectors were developed. The signal-to-noise ratio was improved through averaging of the core and the segment signals, which led to an improvement of the energy resolution of 21% for γ-energies of 60 keV to a FWHM of 870 eV. In combination with crosstalk correction, a clearly improved energy resolution was

  8. Dairy-Rich Diets Augment Fat Loss on an Energy-Restricted Diet: A Multicenter Trial

    Directory of Open Access Journals (Sweden)

    Michael B. Zemel

    2009-09-01

    Full Text Available A 12-week randomized controlled multi-center clinical trial was conducted in 106 overweight and obese adults. Diets were designed to produce a 2,093 kJ/day energy deficit with either low calcium (LC; ~600 mg/day, high calcium (HC; ~1,400 mg/day, or high dairy (HD; three dairy servings, diet totaling ~1,400 mg/day. Ninety-three subjects completed the trial, and 68 met all a priori weekly compliance criteria. Both HC and HD contained comparable levels of calcium, but HC was only ~30% as effective as HD in suppressing 1,25-(OH2D and exerted no significant effects on weight loss or body composition compared to LC. In the group that met compliance criteria, HD resulted in ~two-fold augmentation of fat loss compared to LC and HC (HD: -4.43 ± 0.53 kg; LC: -2.69 ± 0.0.53 kg; HC: -2.23 ± 0.73kg, p < 0.025; assessment of all completers and an intent-to-treat analysis produced similar trends. HD augmentated central (trunk fat loss (HD: -2.38 ± 0.30 kg; HC: -1.42 ± 0.30 kg; LC: -1.36 ± 0.42 kg, p < 0.05 and waist circumference (HD: -7.65 ± 0.75 cm; LC: -4.92 ± 0.74 cm; LC: -4.95 ± 1.05 cm, p < 0.025. Similar effects were noted among all subjects completing the study and in an intent-to-treat analysis. These data indicate that dairy-rich diets augment weight loss by targeting the fat compartment during energy restriction.

  9. Strong-coupling jet energy loss from AdS/CFT

    Science.gov (United States)

    Morad, R.; Horowitz, W. A.

    2014-11-01

    We propose a novel definition of a holographic light hadron jet and consider the phenomenological consequences, including the very first fully self-consistent, completely strong-coupling calculation of the jet nuclear modification factor R AA, which we find compares surprisingly well with recent preliminary data from LHC. We show that the thermalization distance for light parton jets is an extremely sensitive function of the a priori unspecified string initial conditions and that worldsheets corresponding to non-asymptotic energy jets are not well approximated by a collection of null geodesics. Our new string jet prescription, which is defined by a separation of scales from plasma to jet, leads to the re-emergence of the late-time Bragg peak in the instantaneous jet energy loss rate; unlike heavy quarks, the energy loss rate is unusually sensitive to the very definition of the string theory object itself. A straightforward application of the new jet definition leads to significant jet quenching, even in the absence of plasma. By renormalizing the in-medium suppression by that in the vacuum we find qualitative agreement with preliminary CMS RAAjet >( p T) data in our simple plasma brick model. We close with comments on our results and an outlook on future work.

  10. Effects of target electron collisions on energy loss straggling in plasmas of all degeneracies

    Energy Technology Data Exchange (ETDEWEB)

    Barriga Carrasco, Manuel D. [E.T.S.I. Industriales, Universisdad de Castilla La Mancha, Ciudad Real E13071 (Spain)]. E-mail: ManuelD.Barriga@uclm.es

    2007-07-01

    The purpose of the present paper is to describe the effects of target electron collisions on the energy loss straggling in plasmas of any degeneracy. We focus our analysis on targets that are in the limit of weakly coupled electron gases, where the random phase approximation can be applied. This type of plasmas targets has not been studied extensively, though they are very important for inertial confinement fusion. The energy loss straggling is obtained from an exact quantum mechanical evaluation, which takes into account the degeneracy of the target plasma, and later it is compared with common classical and degenerate approximations. Also we consider electron collisions in the exact quantum mechanical straggling calculation. Now the maximum straggling occurs at velocities smaller than for the calculations without considering collisions for all kinds of plasmas analyzed. The straggling remains equal or enhances for velocities less than or equal to the velocity at maximum while is slightly decreases for higher velocities. Differences are significant in all cases, that can let large errors creep on in further energy deposition and projectile range studies.

  11. Effects of target electron collisions on energy loss straggling in plasmas of all degeneracies

    International Nuclear Information System (INIS)

    Barriga Carrasco, Manuel D.

    2007-01-01

    The purpose of the present paper is to describe the effects of target electron collisions on the energy loss straggling in plasmas of any degeneracy. We focus our analysis on targets that are in the limit of weakly coupled electron gases, where the random phase approximation can be applied. This type of plasmas targets has not been studied extensively, though they are very important for inertial confinement fusion. The energy loss straggling is obtained from an exact quantum mechanical evaluation, which takes into account the degeneracy of the target plasma, and later it is compared with common classical and degenerate approximations. Also we consider electron collisions in the exact quantum mechanical straggling calculation. Now the maximum straggling occurs at velocities smaller than for the calculations without considering collisions for all kinds of plasmas analyzed. The straggling remains equal or enhances for velocities less than or equal to the velocity at maximum while is slightly decreases for higher velocities. Differences are significant in all cases, that can let large errors creep on in further energy deposition and projectile range studies

  12. Acceleration, energy loss and screening in strongly-coupled gauge theories

    Science.gov (United States)

    Chernicoff, Mariano; Güijosa, Alberto

    2008-06-01

    We explore various aspects of the motion of heavy quarks in strongly-coupled gauge theories, employing the AdS/CFT correspondence. Building on earlier work by Mikhailov, we study the dispersion relation and energy loss of an accelerating finite-mass quark in Script N = 4 super-Yang-Mills, both in vacuum and in the presence of a thermal plasma. In the former case, we notice that the application of an external force modifies the dispersion relation. In the latter case, we find in particular that when a static heavy quark is accelerated by an external force, its rate of energy loss is initially insensitive to the plasma, and there is a delay before this rate approaches the value derived previously from the analysis of stationary or late-time configurations. Following up on work by Herzog et al., we also consider the evolution of a quark and antiquark as they separate from one another after formation, learning how the AdS/CFT setup distinguishes between the singlet and adjoint configurations, and locating the transition to the stage where the deceleration of each particle is properly accounted for by a constant friction coefficient. Additionally, we examine the way in which the energy of a quark-antiquark pair moving jointly through the plasma scales with the quark mass. We find that the velocity-dependence of the screening length is drastically modified in the ultra-relativistic region, and is comparable with that of the transition distance mentioned above.

  13. Acceleration, energy loss and screening in strongly-coupled gauge theories

    International Nuclear Information System (INIS)

    Chernicoff, Mariano; Gueijosa, Alberto

    2008-01-01

    We explore various aspects of the motion of heavy quarks in strongly-coupled gauge theories, employing the AdS/CFT correspondence. Building on earlier work by Mikhailov, we study the dispersion relation and energy loss of an accelerating finite-mass quark in N = 4 super-Yang-Mills, both in vacuum and in the presence of a thermal plasma. In the former case, we notice that the application of an external force modifies the dispersion relation. In the latter case, we find in particular that when a static heavy quark is accelerated by an external force, its rate of energy loss is initially insensitive to the plasma, and there is a delay before this rate approaches the value derived previously from the analysis of stationary or late-time configurations. Following up on work by Herzog et al., we also consider the evolution of a quark and antiquark as they separate from one another after formation, learning how the AdS/CFT setup distinguishes between the singlet and adjoint configurations, and locating the transition to the stage where the deceleration of each particle is properly accounted for by a constant friction coefficient. Additionally, we examine the way in which the energy of a quark-antiquark pair moving jointly through the plasma scales with the quark mass. We find that the velocity-dependence of the screening length is drastically modified in the ultra-relativistic region, and is comparable with that of the transition distance mentioned above.

  14. Thermo-electrochemical production of compressed hydrogen from methane with near-zero energy loss

    Science.gov (United States)

    Malerød-Fjeld, Harald; Clark, Daniel; Yuste-Tirados, Irene; Zanón, Raquel; Catalán-Martinez, David; Beeaff, Dustin; Morejudo, Selene H.; Vestre, Per K.; Norby, Truls; Haugsrud, Reidar; Serra, José M.; Kjølseth, Christian

    2017-11-01

    Conventional production of hydrogen requires large industrial plants to minimize energy losses and capital costs associated with steam reforming, water-gas shift, product separation and compression. Here we present a protonic membrane reformer (PMR) that produces high-purity hydrogen from steam methane reforming in a single-stage process with near-zero energy loss. We use a BaZrO3-based proton-conducting electrolyte deposited as a dense film on a porous Ni composite electrode with dual function as a reforming catalyst. At 800 °C, we achieve full methane conversion by removing 99% of the formed hydrogen, which is simultaneously compressed electrochemically up to 50 bar. A thermally balanced operation regime is achieved by coupling several thermo-chemical processes. Modelling of a small-scale (10 kg H2 day-1) hydrogen plant reveals an overall energy efficiency of >87%. The results suggest that future declining electricity prices could make PMRs a competitive alternative for industrial-scale hydrogen plants integrating CO2 capture.

  15. Inelastic energy loss in large angle scattering of Ar9+ ions from Au(1 1 1) crystal

    International Nuclear Information System (INIS)

    Pesic, Z.D.; Anton, J.; Bremer, J.H.; Hoffmann, V.; Stolterfoht, N.; Vikor, Gy.; Schuch, R.

    2003-01-01

    The azimuthal angle dependence of the energy loss in large-angle scattering of slow (v∼0.06 a.u.) Ar 9+ ions from a Au(1 1 1) single crystal was investigated. Regarding the kinematics of quasi-single collisions, the smallest energy loss is expected for the azimuthal orientations which correspond to the closest packed atomic row of the crystal. This agrees with the prediction of a trajectory simulation (Marlowe code), but the experimental results don't show such dependence. Thus, we discuss possible inelastic processes as image charge energy gain, electronic energy loss in close collision and the electronic energy loss in the interaction with the electron gas. The observed azimuthal dependence is explained by the change of the electronic stopping power due to the variation of effective electron density sampled by the projectile

  16. Electron transport in furfural: dependence of the electron ranges on the cross sections and the energy loss distribution functions

    Science.gov (United States)

    Ellis-Gibbings, L.; Krupa, K.; Colmenares, R.; Blanco, F.; Muńoz, A.; Mendes, M.; Ferreira da Silva, F.; Limá Vieira, P.; Jones, D. B.; Brunger, M. J.; García, G.

    2016-09-01

    Recent theoretical and experimental studies have provided a complete set of differential and integral electron scattering cross section data from furfural over a broad energy range. The energy loss distribution functions have been determined in this study by averaging electron energy loss spectra for different incident energies and scattering angles. All these data have been used as input parameters for an event by event Monte Carlo simulation procedure to obtain the electron energy deposition patterns and electron ranges in liquid furfural. The dependence of these results on the input cross sections is then analysed to determine the uncertainty of the simulated values.

  17. Energy loss, equilibration, and thermodynamics of a baryon rich strongly coupled quark-gluon plasma

    Energy Technology Data Exchange (ETDEWEB)

    Rougemont, Romulo [Instituto de Física, Universidade de São Paulo, Rua do Matão, 1371, Butantã, CEP 05508-090, São Paulo, SP (Brazil); Ficnar, Andrej [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Finazzo, Stefano I. [Instituto de Física, Universidade de São Paulo, Rua do Matão, 1371, Butantã, CEP 05508-090, São Paulo, SP (Brazil); Instituto de Física Teórica, Universidade do Estado de São Paulo, Rua Dr. Bento T. Ferraz, 271, CEP 01140-070, São Paulo, SP (Brazil); Noronha, Jorge [Instituto de Física, Universidade de São Paulo, Rua do Matão, 1371, Butantã, CEP 05508-090, São Paulo, SP (Brazil); Department of Physics, Columbia University, 538 West 120th Street, New York, NY 10027 (United States)

    2016-04-15

    Lattice data for the QCD equation of state and the baryon susceptibility near the crossover phase transition (at zero baryon density) are used to determine the input parameters of a 5-dimensional Einstein-Maxwell-Dilaton holographic model that provides a consistent holographic framework to study both equilibrium and out-of-equilibrium properties of a hot and baryon rich strongly coupled quark-gluon plasma (QGP). We compare our holographic equation of state computed at nonzero baryon chemical potential, μ{sub B}, with recent lattice calculations and find quantitative agreement for the pressure and the speed of sound for μ{sub B}≤400 MeV. This holographic model is used to obtain holographic predictions for the temperature and μ{sub B} dependence of the drag force and the Langevin diffusion coefficients associated with heavy quark jet propagation as well as the jet quenching parameter q̂ and the shooting string energy loss of light quarks in the baryon dense plasma. We find that the energy loss of heavy and light quarks generally displays a nontrivial, fast-varying behavior as a function of the temperature near the crossover. Moreover, energy loss is also found to generally increase due to nonzero baryon density effects even though this strongly coupled liquid cannot be described in terms of well defined quasiparticle excitations. Furthermore, to get a glimpse of how thermalization occurs in a hot and baryon dense QGP, we study how the lowest quasinormal mode of an external massless scalar disturbance in the bulk is affected by a nonzero baryon charge. We find that the equilibration time associated with the lowest quasinormal mode decreases in a dense medium.

  18. Ion energy loss at maximum stopping power in a laser-generated plasma

    International Nuclear Information System (INIS)

    Cayzac, W.

    2013-01-01

    In the frame of this thesis, a new experimental setup for the measurement of the energy loss of carbon ions at maximum stopping power in a hot laser-generated plasma has been developed and successfully tested. In this parameter range where the projectile velocity is of the same order of magnitude as the thermal velocity of the plasma free electrons, large uncertainties of up to 50% are present in the stopping-power description. To date, no experimental data are available to perform a theory benchmarking. Testing the different stopping theories is yet essential for inertial confinement fusion and in particular for the understanding of the alpha-particle heating of the thermonuclear fuel. Here, for the first time, precise measurements were carried out in a reproducible and entirely characterized beam-plasma configuration. It involved a nearly fully-stripped ion beam probing a homogeneous fully-ionized plasma. This plasma was generated by irradiating a thin carbon foil with two high-energy laser beams and features a maximum electron temperature of 200 eV. The plasma conditions were simulated with a two-dimensional radiative hydrodynamic code, while the ion-beam charge-state distribution was predicted by means of a Monte-Carlo code describing the charge-exchange processes of projectile ions in plasma. To probe at maximum stopping power, high-frequency pulsed ion bunches were decelerated to an energy of 0.5 MeV per nucleon. The ion energy loss was determined by a time-of-flight measurement using a specifically developed chemical-vapor-deposition diamond detector that was screened against any plasma radiation. A first experimental campaign was carried out using this newly developed platform, in which a precision better than 200 keV on the energy loss was reached. This allowed, via the knowledge of the plasma and of the beam parameters, to reliably test several stopping theories, either based on perturbation theory or on a nonlinear T-Matrix formalism. A preliminary

  19. Electronic properties of graphene nano-flakes: Energy gap, permanent dipole, termination effect, and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Sandeep Kumar, E-mail: SandeepKumar.Singh@uantwerpen.be; Peeters, F. M., E-mail: Francois.Peeters@uantwerpen.be [Department of Physics, University of Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium); Neek-Amal, M., E-mail: neekamal@srttu.edu [Department of Physics, University of Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium); Department of Physics, Shahid Rajaee Teacher Training University, Lavizan, Tehran 16788 (Iran, Islamic Republic of)

    2014-02-21

    The electronic properties of graphene nano-flakes (GNFs) with different edge passivation are investigated by using density functional theory. Passivation with F and H atoms is considered: C{sub N{sub c}} X{sub N{sub x}} (X = F or H). We studied GNFs with 10 < N{sub c} < 56 and limit ourselves to the lowest energy configurations. We found that: (i) the energy difference Δ between the highest occupied molecular orbital and the lowest unoccupied molecular orbital decreases with N{sub c}, (ii) topological defects (pentagon and heptagon) break the symmetry of the GNFs and enhance the electric polarization, (iii) the mutual interaction of bilayer GNFs can be understood by dipole-dipole interaction which were found sensitive to the relative orientation of the GNFs, (iv) the permanent dipoles depend on the edge terminated atom, while the energy gap is independent of it, and (v) the presence of heptagon and pentagon defects in the GNFs results in the largest difference between the energy of the spin-up and spin-down electrons which is larger for the H-passivated GNFs as compared to F-passivated GNFs. Our study shows clearly the effect of geometry, size, termination, and bilayer on the electronic properties of small GNFs. This study reveals important features of graphene nano-flakes which can be detected using Raman spectroscopy.

  20. Electron emission and energy loss in grazing collisions of protons with insulator surfaces

    International Nuclear Information System (INIS)

    Gravielle, M. S.; Miraglia, J. E.; Aldazabal, I.; Arnau, A.; Ponce, V. H.; Aumayr, F.; Lederer, S.; Winter, H.

    2007-01-01

    Electron emission from LiF, KCl, and KI crystal surfaces during grazing collisions of swift protons is studied using a first-order distorted-wave formalism. Owing to the localized character of the electronic structure of these surfaces, we propose a model that allows us to describe the process as a sequence of atomic transitions from different target ions. Experimental results are presented for electron emission from LiF and KI and energy loss from KI surfaces. Calculations show reasonable agreement with these experimental data. The role played by the charge of the incident particle is also investigated

  1. Acceleration, Energy Loss and Screening in Strongly-Coupled Gauge Theories

    OpenAIRE

    Chernicoff, Mariano; Guijosa, Alberto

    2008-01-01

    We explore various aspects of the motion of heavy quarks in strongly-coupled gauge theories, employing the AdS/CFT correspondence. Building on earlier work by Mikhailov, we study the dispersion relation and energy loss of an accelerating finite-mass quark in N=4 super-Yang-Mills, both in vacuum and in the presence of a thermal plasma. In the former case, we notice that the application of an external force modifies the dispersion relation. In the latter case, we find in particular that when a ...

  2. Energy Loss of Gluons, Baryons and k-Quarks in an N=4 SYM Plasma

    OpenAIRE

    Chernicoff, Mariano; Guijosa, Alberto

    2006-01-01

    We consider different types of external color sources that move through a strongly-coupled thermal N=4 super-Yang-Mills plasma, and calculate, via the AdS/CFT correspondence, the dissipative force (or equivalently, the rate of energy loss) they experience. A bound state of k quarks in the totally antisymmetric representation is found to feel a force with a nontrivial k-dependence. Our result for k=1 (or k=N-1) agrees at large N with the one obtained recently by Herzog et al. and Gubser, but c...

  3. A method to determine stratification efficiency of thermal energy storage processes independently from storage heat losses

    DEFF Research Database (Denmark)

    Haller, M.Y.; Yazdanshenas, Eshagh; Andersen, Elsa

    2010-01-01

    process is in agreement with the first law of thermodynamics. A comparison of the stratification efficiencies obtained from experimental results of charging, standby, and discharging processes gives meaningful insights into the different mixing behaviors of a storage tank that is charged and discharged......A new method for the calculation of a stratification efficiency of thermal energy storages based on the second law of thermodynamics is presented. The biasing influence of heat losses is studied theoretically and experimentally. Theoretically, it does not make a difference if the stratification...

  4. Electronic energy loss spectra from mono-layer to few layers of phosphorene

    International Nuclear Information System (INIS)

    Mohan, Brij; Thakur, Rajesh; Ahluwalia, P. K.

    2016-01-01

    Using first principles calculations, electronic and optical properties of few-layers phosphorene has been investigated. Electronic band structure show a moderate band gap of 0.9 eV in monolayer phosphorene which decreases with increasing number of layers. Optical properties of few-layers of phosphorene in infrared and visible region shows tunability with number of layers. Electron energy loss function has been plotted and huge red shift in plasmonic behaviours is found. These tunable electronic and optical properties of few-layers of phosphorene can be useful for the applications of optoelectronic devices.

  5. Electronic energy loss spectra from mono-layer to few layers of phosphorene

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Brij, E-mail: brijmohanhpu@yahoo.com; Thakur, Rajesh; Ahluwalia, P. K. [Department of Physics, Himachal Pradesh University, Shimla (HP) India 171005 (India)

    2016-05-23

    Using first principles calculations, electronic and optical properties of few-layers phosphorene has been investigated. Electronic band structure show a moderate band gap of 0.9 eV in monolayer phosphorene which decreases with increasing number of layers. Optical properties of few-layers of phosphorene in infrared and visible region shows tunability with number of layers. Electron energy loss function has been plotted and huge red shift in plasmonic behaviours is found. These tunable electronic and optical properties of few-layers of phosphorene can be useful for the applications of optoelectronic devices.

  6. Gamma non-ionizing energy loss: Comparison with the damage factor in silicon devices

    Science.gov (United States)

    El Allam, E.; Inguimbert, C.; Meulenberg, A.; Jorio, A.; Zorkani, I.

    2018-03-01

    The concept of non-ionizing energy loss (NIEL) has been demonstrated to be a successful approach to describe the displacement damage effects in silicon materials and devices. However, some discrepancies exist in the literature between experimental damage factors and theoretical NIELs. 60Co gamma rays having a low NIEL are an interesting particle source that can be used to validate the NIEL scaling approach. This paper presents different 60Co gamma ray NIEL values for silicon targets. They are compared with the radiation-induced increase in the thermal generation rate of carriers per unit fluence. The differences between the different models, including one using molecular dynamics, are discussed.

  7. Connected Lighting Systems Efficiency Study$-$ PoE Cable Energy Losses, Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Tuenge, Jason [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kelly, Karsten [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Poplawski, Michael [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-11-30

    First report in a study of the efficiency of connected lighting systems. The report summarizes the results of an exploratory study investigating power losses in Ethernet cables used between PoE switches and luminaires in PoE connected lighting systems. Testing was conducted at the Pacific Northwest National Laboratory (PNNL) Connected Lighting Test Bed in September 2017. The results were analyzed to explore the impact of cable selection on PoE lighting system energy efficiency, as well as the effectiveness of guidelines recently introduced by the American National Standards Institute (ANSI) C137 Lighting Systems Committee.

  8. First principles study of electronic properties, interband transitions and electron energy loss of α-graphyne

    Science.gov (United States)

    Behzad, Somayeh

    2016-04-01

    The electronic and optical properties of α-graphyne sheet are investigated by using density functional theory. The results confirm that α-graphyne sheet is a zero-gap semimetal. The optical properties of the α-graphyne sheet such as dielectric function, refraction index, electron energy loss function, reflectivity, absorption coefficient and extinction index are calculated for both parallel and perpendicular electric field polarizations. The optical spectra are strongly anisotropic along these two polarizations. For (E ∥ x), absorption edge is at 0 eV, while there is no absorption below 8 eV for (E ∥ z).

  9. Kinetic Energy Losses and Efficiency of an Axial Turbine Stage in Numerical Modeling of Unsteady Flows

    Directory of Open Access Journals (Sweden)

    A. S. Laskin

    2015-01-01

    Full Text Available The article presents the results of numerical investigation of kinetic energy (KE loss and blading efficiency of the single-stage axial turbine under different operating conditions, characterized by the ratio u/C0. The calculations are performed by stationary (Stage method and nonstationary (Transient method methods using ANSYS CFX. The novelty of this work lies in the fact that the numerical simulation of steady and unsteady flows in a turbine stage is conducted, and the results are obtained to determine the loss of KE, both separately by the elements of the flow range and their total values, in the stage efficiency as well. The results obtained are compared with the calculated efficiency according to one-dimensional theory.To solve these problems was selected model of axial turbine stage with D/l = 13, blade profiles of rotor and stator of constant cross-section, similar to tested ones in inverted turbine when = 0.3. The degree of reactivity ρ = 0.27, the rotor speed was varied within the range 1000 ÷ 1800 rev/min.Results obtained allow us to draw the following conclusions:1. The level of averaged coefficients of total KE losses in the range of from 0.48 to 0.75 is from 18% to 21% when calculating by the Stage method and from 21% to 25% by the Transient one.2. The level of averaged coefficients of KE losses with the output speed of in the specified range is from 9% to 13%, and almost the same when in calculating by Stage and Transient methods.3. Levels of averaged coefficients of KE loss in blade tips (relative to the differential enthalpies per stage are changed in the range: from 4% to 3% (Stage and are stored to be equal to 5% (Transient; from 5% to 6% (Stage and from 6% to 8% (Transient.4. Coefficients of KE losses in blade tips GV and RB are higher in calculations of the model stage using the Transient method than the Stage one, respectively, by = 1.5 ÷ 2.5% and = 4 ÷ 5% of the absolute values. These are values to characterize the KE

  10. Energy loss of argon in a laser-generated carbon plasma.

    Science.gov (United States)

    Frank, A; Blazević, A; Grande, P L; Harres, K; Hessling, T; Hoffmann, D H H; Knobloch-Maas, R; Kuznetsov, P G; Nürnberg, F; Pelka, A; Schaumann, G; Schiwietz, G; Schökel, A; Schollmeier, M; Schumacher, D; Schütrumpf, J; Vatulin, V V; Vinokurov, O A; Roth, M

    2010-02-01

    The experimental data presented in this paper address the energy loss determination for argon at 4 MeV/u projectile energy in laser-generated carbon plasma covering a huge parameter range in density and temperature. Furthermore, a consistent theoretical description of the projectile charge state evolution via a Monte Carlo code is combined with an improved version of the CasP code that allows us to calculate the contributions to the stopping power of bound and free electrons for each projectile charge state. This approach gets rid of any effective charge description of the stopping power. Comparison of experimental data and theoretical results allows us to judge the influence of different plasma parameters.

  11. Prediction of sound transmission loss through multilayered panels by using Gaussian distribution of directional incident energy

    Science.gov (United States)

    Kang; Ih; Kim; Kim

    2000-03-01

    In this study, a new prediction method is suggested for sound transmission loss (STL) of multilayered panels of infinite extent. Conventional methods such as random or field incidence approach often given significant discrepancies in predicting STL of multilayered panels when compared with the experiments. In this paper, appropriate directional distributions of incident energy to predict the STL of multilayered panels are proposed. In order to find a weighting function to represent the directional distribution of incident energy on the wall in a reverberation chamber, numerical simulations by using a ray-tracing technique are carried out. Simulation results reveal that the directional distribution can be approximately expressed by the Gaussian distribution function in terms of the angle of incidence. The Gaussian function is applied to predict the STL of various multilayered panel configurations as well as single panels. The compared results between the measurement and the prediction show good agreements, which validate the proposed Gaussian function approach.

  12. Implications of Postharvest Food Loss/Waste Prevention to Energy and Resources Conservation

    Science.gov (United States)

    Cai, X.; Shafiee-Jood, M.

    2015-12-01

    World's growing demand for food is driven by population and income growth, dietary changes, and the ever-increasing competition between food, feed and bioenergy challenges food security; meanwhile agricultural expansion and intensification threats the environment by the various detrimental impacts. Researchers have attempted to explore strategies to overcome this grand challenge. One of the promising solutions that have attracted considerable attention recently is to increase the efficiency of food supply chain by reducing food loss and waste (FLW). According to recent studies conducted by Food and Agriculture Organization (FAO), United Nation, almost one third of the food produced for human consumption globally is lost or wasted along the food supply chain. This amount of food discarded manifests a missing, yet potential, opportunity to sustainably enhance both food security and environmental sustainability. However, implementing the strategies and technologies for tackling FLW does not come up as an easy solution since it requires economic incentives, benefit and cost analysis, infrastructure development, and appropriate market mechanism. In this presentation I will provide a synthesis of knowledge on the implications of postharvest food loss/waste prevention to energy and resource conservation, environmental protection, as well as food security. I will also discuss how traditional civil and environmental engineering can contribute to the reduction of postharvest food loss, an important issue of sustainable agriculture.

  13. Evaluation of Beam Loss and Energy Depositions for a Possible Phase II Design for LHC Collimation

    International Nuclear Information System (INIS)

    Lari, L.; Assmann, R.; Bracco, C.; Brugger, M.; Cerutti, F.; Doyle, E.; Ferrari, A.; Keller, L.; Lundgren, S.; Markiewicz, Thomas W.; Mauri, M.; Redaelli, S.; Sarchiapone, L.; Smith, J.; Vlachoudis, V.; Weiler, T.

    2011-01-01

    The LHC beams are designed to have high stability and to be stored for many hours. The nominal beam intensity lifetime is expected to be of the order of 20h. The Phase II collimation system has to be able to handle particle losses in stable physics conditions at 7 TeV in order to avoid beam aborts and to allow correction of parameters and restoration to nominal conditions. Monte Carlo simulations are needed in order to evaluate the behavior of metallic high-Z collimators during operation scenarios using a realistic distribution of losses, which is a mix of the three limiting halo cases. Moreover, the consequences in the IR7 insertion of the worst (case) abnormal beam loss are evaluated. The case refers to a spontaneous trigger of the horizontal extraction kicker at top energy, when Phase II collimators are used. These studies are an important input for engineering design of the collimation Phase II system and for the evaluation of their effect on adjacent components. The goal is to build collimators that can survive the expected conditions during LHC stable physics runs, in order to avoid quenches of the SC magnets and to protect other LHC equipments.

  14. Evaluation of Beam Losses And Energy Deposition for a Possible Phase II Design for LHC Collimation

    International Nuclear Information System (INIS)

    Lari, L.; Bracco, C.; Assmann, R.W.; Brugger, M.; Cerutti, F.; Ferrari, A.; Mauri, M.; Redaelli, S.; Sarchiapone, L.; Vlachoudis, V.; Weiler, T.; Doyle, J.E.; Keller, L.; Lundgren, S.A.; Markiewicz, T.W.; Smith, J.C.

    2011-01-01

    The Large Hadron Collider (LHC) beams are designed to have high stability and to be stored for many hours. The nominal beam intensity lifetime is expected to be of the order of 20h. The Phase II collimation system has to be able to handle particle losses in stable physics conditions at 7 TeV in order to avoid beam aborts and to allow correction of parameters and restoration to nominal conditions. Monte Carlo simulations are needed in order to evaluate the behavior of metallic high-Z collimators during operation scenarios using a realistic distribution of losses, which is a mix of the three limiting halo cases. Moreover, the consequences in the IR7 insertion of the worst (case) abnormal beam loss are evaluated. The case refers to a spontaneous trigger of the horizontal extraction kicker at top energy, when Phase II collimators are used. These studies are an important input for engineering design of the collimation Phase II system and for the evaluation of their effect on adjacent components. The goal is to build collimators that can survive the expected conditions during LHC stable physics runs, in order to avoid quenches of the SC magnets and to protect other LHC equipments.

  15. Predicting successful long-term weight loss from short-term weight-loss outcomes: new insights from a dynamic energy balance model (the POUNDS Lost study).

    Science.gov (United States)

    Thomas, Diana M; Ivanescu, Andrada E; Martin, Corby K; Heymsfield, Steven B; Marshall, Kaitlyn; Bodrato, Victoria E; Williamson, Donald A; Anton, Stephen D; Sacks, Frank M; Ryan, Donna; Bray, George A

    2015-03-01

    Currently, early weight-loss predictions of long-term weight-loss success rely on fixed percent-weight-loss thresholds. The objective was to develop thresholds during the first 3 mo of intervention that include the influence of age, sex, baseline weight, percent weight loss, and deviations from expected weight to predict whether a participant is likely to lose 5% or more body weight by year 1. Data consisting of month 1, 2, 3, and 12 treatment weights were obtained from the 2-y Preventing Obesity Using Novel Dietary Strategies (POUNDS Lost) intervention. Logistic regression models that included covariates of age, height, sex, baseline weight, target energy intake, percent weight loss, and deviation of actual weight from expected were developed for months 1, 2, and 3 that predicted the probability of losing model. The AUC statistic quantified the ROC curve's capacity to classify participants likely to lose models yielding the highest AUC were retained as optimal. For comparison with current practice, ROC curves relying solely on percent weight loss were also calculated. Optimal models for months 1, 2, and 3 yielded ROC curves with AUCs of 0.68 (95% CI: 0.63, 0.74), 0.75 (95% CI: 0.71, 0.81), and 0.79 (95% CI: 0.74, 0.84), respectively. Percent weight loss alone was not better at identifying true positives than random chance (AUC ≤0.50). The newly derived models provide a personalized prediction of long-term success from early weight-loss variables. The predictions improve on existing fixed percent-weight-loss thresholds. Future research is needed to explore model application for informing treatment approaches during early intervention. © 2015 American Society for Nutrition.

  16. Inelastic energy loss of light particles scattered by solid surfaces at low energy: influence of the 'gap'

    International Nuclear Information System (INIS)

    Boudjema, M.; D'bichi, N.; Boudouma, Y.; Chami, A.C.; Arezki, B.; Khalal, K.; Benazeth, C.; Benoit-Cattin, P.

    2000-01-01

    The energy spectra of particles scattered by solid surfaces are used to determine the inelastic energy loss at low energy. Assuming the binary collision approximation, a modified TRIM code provides length distributions which are converted to time-of-flight (TOF) spectra by using the friction coefficient as an adjustable parameter. Owing to the nonlinear effects occurring in this energy range, the theoretical value of the electronic stopping power is performed from electron-particle scattering cross-section using a screened potential and so, the phase shifts, obtained self-consistently in the framework of density functional theory (DFT). In the case of He/a:Si interaction at 4 keV, the standard model leads to a largely overestimated value. This fact has been attributed to the presence of the electron energy gap E G and to the structure of the valence band. We verify this assumption in a non-static model involving all electrons of the valence band with a threshold condition v e '2 >v F 2 +2E G , where v F is the Fermi velocity and v e the electron velocity after scattering (non-static extended collisional model). The theoretical results agree very well with the experimental ones for He colliding three targets: a:Si, a:Ge and polycrystalline Ni at 4 keV. The calculations performed for the velocity range below 1 a.u. confirm the important role of the gap and the band structure in the lowering of stopping power at low velocity

  17. Radiative loss and charge exchange in low energy Na - Ca+ collisions

    Science.gov (United States)

    McLaughlin, B. M.; McAlpine, K.; McCann, J. F.; Pattillo, R.; Stancil, P. C.; Forrey, R. C.; Babb, J. F.

    2016-05-01

    Experiments on radiative loss and capture are currently being performed at the University of Connecticut. In response to this experimental effort we have performed detailed calculations for a variety of loss and capture processes. Several low lying states of the NaCa+ cation are used with the accurate potentials energy curves, transition dipole moments and non-adiabatic coupling matrix elements between the states, obtained at the MRCI+Q level of approximation with the MOLPRO suite of quantum chemistry codes. Cross sections and rate coefficients are calculated for radiative charge transfer (RCX), radiative association (RA) and charge exchange in a fully quantum molecular close-coupling (MOCC) approximation at the higher energies. We use a variety of approaches, the optical potential method, semi-classical and MOCC methods to compare and contrast approximations. In addition a kinetic theory recently applied to SiO is utilized which illustrates the dramatic impact resonances have on the radiative association rates. Supported by NASA and HLRS at Stuttgart University.

  18. Energy loss optimization of run-off-road wheels applying imperialist competitive algorithm

    Directory of Open Access Journals (Sweden)

    Hamid Taghavifar

    2014-08-01

    Full Text Available The novel imperialist competitive algorithm (ICA has presented outstanding fitness on various optimization problems. Application of meta-heuristics has been a dynamic studying interest of the reliability optimization to determine idleness and reliability constituents. The application of a meta-heuristic evolutionary optimization method, imperialist competitive algorithm (ICA, for minimization of energy loss due to wheel rolling resistance in a soil bin facility equipped with single-wheel tester is discussed. The required data were collected thorough various designed experiments in the controlled soil bin environment. Local and global searching of the search space proposed that the energy loss could be reduced to the minimum amount of 15.46 J at the optimized input variable configuration of wheel load at 1.2 kN, tire inflation pressure of 296 kPa and velocity of 2 m/s. Meanwhile, genetic algorithm (GA, particle swarm optimization (PSO and hybridized GA–PSO approaches were benchmarked among the broad spectrum of meta-heuristics to find the outperforming approach. It was deduced that, on account of the obtained results, ICA can achieve optimum configuration with superior accuracy in less required computational time.

  19. X-ray Spectroscopic Characterization of Plasma for a Charged-Particle Energy-Loss Experiment

    Science.gov (United States)

    Hoffman, Nm; Lee, Cl; Wilson, Dc; Barnes, Cris W.; Petrasso, Rd; Li, C.; Hicks, D.

    2000-10-01

    We are pursuing an approach to a charged-particle energy-loss experiment in which charged fusion products from an imploded ICF capsule travel through a well characterized, spatially separate plasma. For this purpose, a fully ionized, uniform, nearly steady-state carbon-hydrogen plasma will be created by laser irradiation of a plastic foil. The temperature and density structure of this plasma must be determined accurately in order to relate observed energy losses to predictions of theory. Various methods for diagnosing the plasma are possible, including Thomson scattering. Alternatively, if a small admixture of higher-Z material such as chlorine is included in the plastic, x-ray spectroscopic techniques will allow the plasma's temperature and density to be determined. Electron temperature is inferred from the ratios of line strengths of various chlorine ion stages, while electron density is determined from the spectra of lithium-like satellite lines near the He beta line of helium-like chlorine. We present results from detailed-configuration accounting (DCA) models of line emission from C+H+Cl plasmas, and estimate the accuracy with which such plasmas can be characterized.

  20. Complex suppression patterns distinguish between major energy loss effects in Quark–Gluon Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Djordjevic, Magdalena, E-mail: magda@ipb.ac.rs

    2016-12-10

    Interactions of high momentum partons with Quark–Gluon Plasma created in relativistic heavy-ion collisions provide an excellent tomography tool for this new form of matter. Recent measurements for charged hadrons and unidentified jets at the LHC show an unexpected flattening of the suppression curves at high momentum, exhibited when either momentum or the collision centrality is changed. Furthermore, a limited data available for B probes indicate a qualitatively different pattern, as nearly the same flattening is exhibited for the curves corresponding to two opposite momentum ranges. We here show that the experimentally measured suppression curves are well reproduced by our theoretical predictions, and that the complex suppression patterns are due to an interplay of collisional, radiative energy loss and the dead-cone effect. Furthermore, for B mesons, we predict that the uniform flattening of the suppression indicated by the limited dataset is in fact valid across the entire span of the momentum ranges, which will be tested by the upcoming experiments. Overall, the study presented here, provides a rare opportunity for pQCD theory to qualitatively distinguish between the major energy loss mechanisms at the same (nonintuitive) dataset.