WorldWideScience

Sample records for conversion electron spectrum

  1. Conversion electron surface imaging

    CERN Document Server

    Irwin, G M; Wehner, A

    1999-01-01

    A method of imaging the Moessbauer absorption over the surface of a sample based on counting conversion electrons emitted from the surface following resonant absorption of gamma radiation is described. This Conversion Electron Surface Imaging (CESI) method is somewhat analogous to Magnetic Resonance Imaging (MRI), particularly chemical shift imaging, and similar tomographic reconstruction techniques are involved in extracting the image. The theory behind the technique and a prototype device is described, as well as the results of proof-of-principle experiments which demonstrate the function of the device. Eventually this same prototype device will be part of a system to determine the spatial variation of the Moessbauer spectrum over the surface of a sample. Applications include imaging of variations of surface properties of steels and other iron containing alloys, as well as other surfaces over which sup 5 sup 7 Fe has been deposited.

  2. Measurement of Hot Electron Spectrum

    Institute of Scientific and Technical Information of China (English)

    LIYe-jun; SHANYu-sheng; ZHANGHai-feng; ZHANGJi; WANGLei-jian; TANGXiu-zhang

    2003-01-01

    The hot electron spectrum was measured using 180°electron magnetic spectrometer through the irradiation of solid Cu target by an intense, near infrared(744 nm), P-polarized light, femtosecond (120 fs) laser pulse with free pre-pulse, and the intensity of laser is 1016 W/cm2 with 45° incidence. And the spectrometer was located in the direction of laser right reflection.

  3. In-trap conversion electron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Weissman, L. E-mail: weissman@nscl.msu.edu; Ames, F.; Aeysto, J.; Forstner, O.; Reisinger, K.; Rinta-Antila, S

    2002-10-21

    The Penning trap REXTRAP at ISOLDE was used to test the feasibility of in-trap conversion electron spectroscopy. The results of simulations, experiments with solid conversion electron sources as well as first on-line tests with trapped radioactive ions are presented. In addition to obtaining high-resolution spectroscopic data, the detection of conversion electrons was found to be a useful tool for the diagnostics of the trap operation. The tests proved the feasibility of in-trap spectroscopy but also revealed some potential problems to be addressed in the future.

  4. In-trap conversion electron spectroscopy

    CERN Document Server

    Weissman, L; Äystö, J; Forstner, O; Reisinger, K; Rinta-Antila, S

    2002-01-01

    The Penning trap REXTRAP at ISOLDE was used to test the feasibility of in-trap conversion electron spectroscopy. The results of simulations, experiments with solid conversion electron sources as well as first on-line and tests with trapped radioactive ions are presented. In addition to obtaining high-resolution spectroscopic data, the detection of conversion electrons was found to be a useful tool for the diagnostics of the trap operation. The tests proved the feasibility of in-trap spectroscopy but also revealed some potential problems to be addressed in the future.

  5. Solar spectrum conversion for photovoltaics using nanoparticles

    NARCIS (Netherlands)

    Sark, W.G.J.H.M. van; Meijerink, A.; Schropp, R.E.I.

    2012-01-01

    The possibility to tune chemical and physical properties in nanosized materials has a strong impact on a variety of technologies, including photovoltaics. One of the prominent research areas of nanomaterials for photovoltaics involves spectral conversion. Conventional single-junction semiconductor s

  6. Alpha and conversion electron spectroscopy of 238,239Pu and 241Am and alpha-conversion electron coincidence measurements

    Science.gov (United States)

    Dion, Michael P.; Miller, Brian W.; Warren, Glen A.

    2016-09-01

    A technique to determine the isotopic constituents of a mixed actinide sample has been proposed by a coincident alpha-conversion electron measurement. This presents a unique signature to allow the unfolding of isotopes that possess overlapping alpha particle energy and reduce backgrounds of an unseparated sample. The work presented here are results of conversion electron spectroscopy of 241Am, 238Pu and 239Pu using a dual-stage peltier-cooled 25 mm2 silicon drift detector and alpha spectroscopy with a passivated ion implanted planar silicon detector. The conversion electron spectra were evaluated from 20-55 keV based on fits to the dominant conversion electron emissions, which allowed the relative conversion electron emission intensities to be determined. These measurements provide crucial singles spectral information and calibration to aid in the coincident measurement approach. Furthermore, an alpha-conversion electron spectrometer was assembled using the silicon based detectors described and results of a coincident spectrum analysis is reported for 241Am.

  7. Measurement of internal conversion electrons from Gd neutron capture

    Energy Technology Data Exchange (ETDEWEB)

    Kandlakunta, P. [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210 (United States); Cao, L.R., E-mail: cao.152@osu.edu [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210 (United States); Mulligan, P. [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210 (United States)

    2013-03-21

    Gadolinium (Gd) is a suitable material for neutron conversion because of its superior neutron absorption cross-section. However, the principal secondary particles that generate electron-hole pairs in a semiconductor detector after Gd neutron capture are low-energy internal conversion (IC) electrons. We measured the IC electron spectrum due to Gd neutron capture by using a thermal neutron beam and a digitizer-based multidetector spectroscopy. We also discussed the effective use of the IC electrons in the context of a twin-detector design and the associated gamma-ray rejection issues. Extensive simulations of the spectra of IC electrons and gamma rays agreed well with the experimental results; both types of results support the feasibility of the proposed n–γ separation method.

  8. Thermo electronic laser energy conversion

    Science.gov (United States)

    Hansen, L. K.; Rasor, N. S.

    1976-01-01

    The thermo electronic laser energy converter (TELEC) is described and compared to the Waymouth converter and the conventional thermionic converter. The electrical output characteristics and efficiency of TELEC operation are calculated for a variety of design variables. Calculations and results are briefly outlined. It is shown that the TELEC concept can potentially convert 25 to 50 percent of incident laser radiation into electric power at high power densities and high waste heat rejection temperatures.

  9. Ultrafast Electron Dynamics in Solar Energy Conversion.

    Science.gov (United States)

    Ponseca, Carlito S; Chábera, Pavel; Uhlig, Jens; Persson, Petter; Sundström, Villy

    2017-08-23

    Electrons are the workhorses of solar energy conversion. Conversion of the energy of light to electricity in photovoltaics, or to energy-rich molecules (solar fuel) through photocatalytic processes, invariably starts with photoinduced generation of energy-rich electrons. The harvesting of these electrons in practical devices rests on a series of electron transfer processes whose dynamics and efficiencies determine the function of materials and devices. To capture the energy of a photogenerated electron-hole pair in a solar cell material, charges of opposite sign have to be separated against electrostatic attractions, prevented from recombining and being transported through the active material to electrodes where they can be extracted. In photocatalytic solar fuel production, these electron processes are coupled to chemical reactions leading to storage of the energy of light in chemical bonds. With the focus on the ultrafast time scale, we here discuss the light-induced electron processes underlying the function of several molecular and hybrid materials currently under development for solar energy applications in dye or quantum dot-sensitized solar cells, polymer-fullerene polymer solar cells, organometal halide perovskite solar cells, and finally some photocatalytic systems.

  10. Weight Estimation of Electronic Power Conversion Systems

    OpenAIRE

    Wen, Bo

    2011-01-01

    Electronic power conversion systems with large number of power converters have a variety of applications, such as data center, electric vehicles and future smart â nanogridâ in residential home. Those systems could have very different architectures. For example, one system could be based on ac, dc or hybrid power distribution bus, and the bus voltage could be different. Also those systems have great need to develop low-cost architectures which reduce weight, increase efficiency and improve...

  11. Education and solar conversion. Demonstrating electron transfer

    Energy Technology Data Exchange (ETDEWEB)

    Smestad, Greg P. [Institute of Physical Chemistry, ICP-2, Swiss Federal Institute of Technology, EPFL, CH-1015 Lausanne (Switzerland)

    1998-07-23

    A simplified solar cell fabrication procedure is presented that uses natural anthocyanin or chlorophyll dyes extracted from plants. This procedure illustrates how interdisciplinary science can be taught at lower division university and upper division high school levels for an understanding of renewable energy as well as basic science concepts. Electron transfer occurs on the Earth in the mitochondrial membranes found in living cells, and in the thylakoid membranes found in the photosynthetic cells of green plants. Since we depend on the results of this electron and energy transfer, e.g. in our use of petroleum and agricultural products, it is desirable to understand and communicate how the electron transfer works. The simplified solar cell fabrication procedure, based on nanocrystalline dye-sensitized solar cells, has therefore been developed so that it can be inexpensively reproduced and utilized in the teaching of basic principles in biology, chemistry, physics, and environmental science. A water-based solution of commercial nanocrystalline titanium dioxide (TiO{sub 2}) powder is used to deposit a highly porous semiconductor electron acceptor. This acceptor couples the light-driven processes occurring at an organic dye to the macroscopic world and an external electrical circuit. Materials science and semiconductor physics are emphasized during the deposition of the sintered TiO{sub 2} nanocrystalline ceramic film. Chelation, complexation and molecular self-assembly are demonstrated during the attachment of the dye molecule to the surface of the TiO{sub 2} semiconductor particles. Environmental chemistry and energy conversion can be linked to these concepts via the regenerative oxidation and reduction cycle found in the cell. The resulting device, made in under 3 h, can be used as a light detector or power generator that produces 0.4-0.5 V at open circuit, and 1-2 mA per square cm under solar illumination

  12. Alpha and conversion electron spectroscopy of {sup 238,239}Pu and {sup 241}Am and alpha-conversion electron coincidence measurements

    Energy Technology Data Exchange (ETDEWEB)

    Dion, Michael P., E-mail: michael.dion@pnnl.gov; Miller, Brian W.; Warren, Glen A.

    2016-09-11

    A technique to determine the isotopic constituents of a mixed actinide sample has been proposed by a coincident alpha-conversion electron measurement. This presents a unique signature to allow the unfolding of isotopes that possess overlapping alpha particle energy and reduce backgrounds of an unseparated sample. The work presented here are results of conversion electron spectroscopy of {sup 241}Am, {sup 238}Pu and {sup 239}Pu using a dual-stage peltier-cooled 25 mm{sup 2} silicon drift detector and alpha spectroscopy with a passivated ion implanted planar silicon detector. The conversion electron spectra were evaluated from 20–55 keV based on fits to the dominant conversion electron emissions, which allowed the relative conversion electron emission intensities to be determined. These measurements provide crucial singles spectral information and calibration to aid in the coincident measurement approach. Furthermore, an alpha-conversion electron spectrometer was assembled using the silicon based detectors described and results of a coincident spectrum analysis is reported for {sup 241}Am.

  13. Photoelectrochemical solar conversion systems molecular and electronic aspects

    CERN Document Server

    Munoz, Andres G

    2012-01-01

    Providing new insights into the molecular and electronic processes involved in the conversion of sunlight into chemical products, Photoelectrochemical Solar Conversion Systems: Molecular and Electronic Aspects begins with an historical overview and a survey of recent developments in the electrochemistry of semiconductors and spectroscopic techniques. It then provides a comprehensive introduction to the science of conversion cells, reviews current issues and potential directions, and covers a wide range of materials from organic to inorganic cells.Employing a tutorial organization with balanced

  14. Alpha and conversion electron spectroscopy of 238,239Pu and 241Am and alpha-conversion electron coincidence measurements

    Energy Technology Data Exchange (ETDEWEB)

    Dion, Michael P.; Miller, Brian W.; Warren, Glen A.

    2016-09-01

    A technique to determine the isotopics of a mixed actinide sample has been proposed by measuring the coincidence of the alpha particle during radioactive decay with the conversion electron (or Auger) emitted during the relaxation of the daughter isotope. This presents a unique signature to allow the deconvolution of isotopes that possess overlapping alpha particle energy. The work presented here are results of conversion electron spectroscopy of 241Am, 238Pu and 239Pu using a dual-stage peltier-cooled 25 mm2 silicon drift detector. A passivated ion implanted planar silicon detector provided measurements of alpha spectroscopy. The conversion electron spectra were evaluated from 20–55 keV based on fits to the dominant conversion electron emissions, which allowed the relative conversion electron emission intensities to be determined. These measurements provide crucial singles spectral information to aid in the coincident measurement approach.

  15. Electron Ionization Mass Spectrum of Tellurium Hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Richard A.; McNamara, Bruce K.; Barinaga, Charles J.; Peterson, James M.; Govind, Niranjan; Andersen, Amity; Abrecht, David G.; Schwantes, Jon M.; Ballou, Nathan E.

    2015-05-18

    The first electron ionization mass spectrum of tellurium hexafluoride (TeF6) is reported. The starting material was produced by direct fluorination of Te metal or TeO2 with nitrogen trifluoride. Formation of TeF6 was confirmed through cryogenic capture of the tellurium fluorination product and analysis through Raman spectroscopy. The eight natural abundance isotopes were observed for each of the set of fragment ions: TeF5+, TeF4+ TeF3+, TeF2+, TeF1+, and Te+, Te2+. A trend in increasing abundance was observed for the even fluoride bearing ions: TeF1+ < TeF3+ < TeF5+, and a decreasing abundance was observed for the even fragment series: Te(0)+ > TeF2+ > TeF4+ > TeF6+, with the molecular ion TeF6+ not observed at all. Density functional theory based electronic structure calculations were used to calculate optimized ground state geometries of these gas phase species and their relative stabilities explain the trends in the data and the lack of observed signal for TeF6+.

  16. Electron ionization mass spectrum of tellurium hexafluoride.

    Science.gov (United States)

    Clark, Richard A; McNamara, Bruce K; Barinaga, Charles J; Peterson, James M; Govind, Niranjan; Andersen, Amity; Abrecht, David G; Schwantes, Jon M; Ballou, Nathan E

    2015-05-18

    The electron ionization mass spectrum of tellurium hexafluoride (TeF6) is reported for the first time. The starting material was produced by direct fluorination of Te metal or TeO2 with nitrogen trifluoride. Formation of TeF6 was confirmed through cryogenic capture of the tellurium fluorination product and analysis through Raman spectroscopy. The eight natural abundance isotopes were observed for each of the set of fragment ions: TeF5(+), TeF4(+) TeF3(+), TeF2(+), TeF1(+), and Te(+), Te2(+). A trend in increasing abundance was observed for the odd fluoride bearing ions, TeF1(+) TeF2(+) > TeF4(+) > TeF6(+), with the molecular ion TeF6(+) not observed at all. Density functional theory based electronic structure calculations were used to calculate optimized ground state geometries of these gas phase species, and their relative stabilities explain the trends in the data and the lack of observed signal for TeF6(+).

  17. Modal spectrum in spontaneous parametric down-conversion with noncollinear phase matching

    CSIR Research Space (South Africa)

    Zhang, Y

    2014-06-01

    Full Text Available We investigate the effect of the down-conversion angle between the signal and idler beams in spontaneous parametric down-conversion on the bandwidth of the modal spectrum (Schmidt number) of the down-converted quantum state. For this purpose, we...

  18. SPectrometer for Internal Conversion Electrons (SPICE) at TRIUMF-ISAC

    Science.gov (United States)

    Smallcombe, J.; Moukaddam, M.; Evitts, L. J.; Garnsworthy, A. B.; Hallam, S.; Andreoiu, C.; Ball, G. C.; Bolton, C.; Caballero-Folch, R.; Constable, M.; Cross, D. S.; Garrett, P. E.; Hackman, G.; Henderson, J.; Henderson, R.; Ketelhut, S.; Kruecken, R.; Kurchaninov, L.; Park, J.; Pore, J. L.; Rand, E. T.; Ruotsalainen, P.; Smith, J. K.; Svensson, C. E.; Williams, M.

    2016-09-01

    A new ancillary detector, SPICE (SPectrometer for Internal Conversion Electrons) has been constructed and recently commissioned for use with radioactive ion beams at the TRIUMF-ISAC II facility. SPICE is designed to be operated in conjunction with the TIGRESS High-Purity Germanium (HPGe) spectrometer to perform combined in-beam γ-ray and internal-conversion-electron spectroscopy. The main feature of SPICE is high effciency over a wide range of electron energies from 100 to 3500 keV, with an effective reduction of beam-induced backgrounds. SPICE will be a powerful tool to measure conversion coeffcients and E0 transitions in atomic nuclei. A recent in-beam commissioning experiment demonstrates the effectiveness of the basic design concept of SPICE in background suppression.

  19. Laser X-ray Conversion and Electron Thermal Conductivity*

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The influence of electron thermal conductivity on the laser x-ray conversion in the coupling of 3ωo laser with Au plane target has been investigated by using a non-LTE radiation hydrodynamic code. The non-local electron thermal conductivity is introduced and compared with the other two kinds of the flux-limited Spitzer-Harm description. The results show that the non-local thermal conductivity causes the increase of the laser x-ray conversion efficiency andimportant changes of the plasma state and coupling feature

  20. Resonant Spin-Flavor Conversion of Supernova Neutrinos: Dependence on Electron Mole Fraction

    CERN Document Server

    Yoshida, T; Kimura, K; Yokomakura, H; Kawagoe, S; Kajino, T

    2009-01-01

    Detailed dependence of resonant spin-flavor (RSF) conversion of supernova neutrinos on electron mole fraction Ye is investigated. Supernova explosion forms a hot-bubble and neutrino-driven wind region of which electron mole fraction exceeds 0.5 in several seconds after the core collapse. When a higher resonance of the RSF conversion is located in the innermost region, flavor change of the neutrinos strongly depends on the sign of 1-2Ye. At an adiabatic high RSF resonance the flavor conversion of bar{nu}_e -> nu_{mu,tau} occurs in Ye 0.5 and inverted mass hierarchy. In other cases of Ye values and mass hierarchies, the conversion of nu_e -> bar{nu}_{mu,tau} occurs. The final bar{nu}_e spectrum is evaluated in the cases of Ye 0.5 taking account of the RSF conversion. Based on the obtained result, time variation of the event number ratios of low bar{nu}_e energy to high bar{nu}_e energy is discussed. In normal mass hierarchy, an enhancement of the event ratio should be seen in the period when the electron frac...

  1. On the merits of conversion electron Mossbauer spectroscopy in geosciences

    DEFF Research Database (Denmark)

    Gunnlaugsson, H.P.; Bertelsen, P.; Budtz-Jørgensen, Carl;

    2006-01-01

    Described are some applications of conversion electron Mossbauer spectroscopy (CEMS) in geosciences. It is shown how easily this technique can be applied in existing Mossbauer laboratories to investigate natural samples. Some examples demonstrate the kind of information CEMS can give...... on the weathering history or mechanical properties of samples. The possible application of CEMS on Mars is discussed....

  2. Electron energy spectrum in core-shell elliptic quantum wire

    Directory of Open Access Journals (Sweden)

    V.Holovatsky

    2007-01-01

    Full Text Available The electron energy spectrum in core-shell elliptic quantum wire and elliptic semiconductor nanotubes are investigated within the effective mass approximation. The solution of Schrodinger equation based on the Mathieu functions is obtained in elliptic coordinates. The dependencies of the electron size quantization spectrum on the size and shape of the core-shell nanowire and nanotube are calculated. It is shown that the ellipticity of a quantum wire leads to break of degeneration of quasiparticle energy spectrum. The dependences of the energy of odd and even electron states on the ratio between semiaxes are of a nonmonotonous character. The anticrosing effects are observed at the dependencies of electron energy spectrum on the transversal size of the core-shell nanowire.

  3. THE SECONDARY ELECTRONS SPECTRUM OF POLYANILINE IN XPS

    Institute of Scientific and Technical Information of China (English)

    WAN Meixiang; GUO Kezhen

    1992-01-01

    The secondary electrons spectrum in XPS can be used to determine the work function of polyaniline (PANI). It is shown that the work function of PANI depends on the protonation state and the polymerization method used.

  4. Conversion electron spectroscopy of isobarically purified trapped radioactive ions

    Energy Technology Data Exchange (ETDEWEB)

    Rissanen, J.; Elomaa, V.V.; Eronen, T.; Hakala, J.; Jokinen, A.; Rahaman, S.; Rinta-Antila, S.; Aeystoe, J. [University of Jyvaeskylae, Department of Physics, P.O.B. 35 (Finland)

    2007-11-15

    The feasibility of the JYFLTRAP for in-trap spectroscopy has been studied. Several internally converted transitions have been measured for isomers of fission products with good accuracy. High-resolution spectroscopic data free of source effects have been obtained proving that trapped radioactive ions can provide excellent conversion electron sources. The shortest-lived isomer studied in this work was {sup 117m} Pd with a half-life of 19.1 ms, for which a superior peak-to-total ratio and an excellent line shape at the 9.9 keV conversion electron line have been observed. Detection efficiencies and related phenomena of the present setup are analyzed. (orig.)

  5. Using Self-Management to Improve the Reciprocal Social Conversation of Children with Autism Spectrum Disorder

    Science.gov (United States)

    Koegel, Lynn Kern; Park, Mi N.; Koegel, Robert L.

    2014-01-01

    Individuals with autism spectrum disorders often exhibit difficulties with reciprocal social conversation, engaging in limited verbal exchanges, even when language structures are intact. This study employed a multiple baseline design to examine the effectiveness of a self-management intervention targeting (1) on-topic responsiveness to a…

  6. Using Reframing to Reduce Negative Statements in Social Conversation for Adults with Autism Spectrum Disorder

    Science.gov (United States)

    Koegel, Lynn Kern; Navab, Anahita; Ashbaugh, Kristen; Koegel, Robert L.

    2016-01-01

    This study examined the effects of teaching the reframing of negative statements through self-management and video-feedback on social conversation in adults with autism spectrum disorder (ASD). A multiple baseline design across five participants showed that, following intervention, all were able to increase their positive and neutral statements…

  7. Conversion electrons used to monitor the energy scale of electron spectrometer near tritium endpoint - a simulation study

    CERN Document Server

    Rysavy, M

    2006-01-01

    Measurements of the endpoint region of the tritium beta-decay spectrum provides good possibility to determine neutrino mass. This, however, needs a perfect monitoring of the spectrometer energy scale. A parallel measurement of electron line of known energy - in particular the 83mKr conversion K-line - may serve well to this purpose. The 83Rb decaying to 83mKr seems to be a very suitable radioactive source due to its halflife of 86.2 day. In this work, we determine the amount of 83Rb which is necessary for a successful monitoring.

  8. Modeling power electronics and interfacing energy conversion systems

    CERN Document Server

    Simões, Marcelo Godoy

    2017-01-01

    Discusses the application of mathematical and engineering tools for modeling, simulation and control oriented for energy systems, power electronics and renewable energy. This book builds on the background knowledge of electrical circuits, control of dc/dc converters and inverters, energy conversion and power electronics. The book shows readers how to apply computational methods for multi-domain simulation of energy systems and power electronics engineering problems. Each chapter has a brief introduction on the theoretical background, a description of the problems to be solved, and objectives to be achieved. Block diagrams, electrical circuits, mathematical analysis or computer code are covered. Each chapter concludes with discussions on what should be learned, suggestions for further studies and even some experimental work.

  9. Monte Carlo Evaluation of Tritium Beta Spectrum Energy Deposition in Gallium Nitride (GaN) Direct Energy Conversion Devices

    Science.gov (United States)

    2014-09-01

    Monte Carlo Evaluation of Tritium Beta Spectrum Energy Deposition in Gallium Nitride (GaN) Direct Energy Conversion Devices by Marc Litz...MD 20783-1138 ARL-TR-7082 September 2014 Monte Carlo Evaluation of Tritium Beta Spectrum Energy Deposition in Gallium Nitride (GaN... Tritium Beta Spectrum Energy Deposition in Gallium Nitride (GaN) Direct Energy Conversion Devices 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM

  10. The {nu}MSM and muon to electron conversion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Canetti, Laurent, E-mail: laurent.canetti@epfl.ch; Shaposhnikov, Mikhail, E-mail: mikhail.shaposhnikov@epfl.ch [EPFL, ITP (Switzerland)

    2013-03-15

    We review briefly the different constraints on the three right-handed neutrinos of the {nu}MSM, an extension of the Standard Model that can explain baryon asymmetry, dark matter and neutrino masses. We include in the discussion the proposed experiments on muon to electron conversion Mu2e (Carey et al., Mu2e Collaboration, 2012), COMET and PRISM (Hungerford, COMET Collaboration, AIP Conf Proc 1182:694, 2009; Cui et al., COMET Collaboration, 2012). We find that the expected sensitivity of these experiments is weaker by about two orders of magnitude than the constraints coming from successful baryogenesis.

  11. Radiation spectrum of an electron moving in a spiralin medium

    Directory of Open Access Journals (Sweden)

    A.V.Konstantinovich

    2007-01-01

    Full Text Available The action of the Doppler effect on the particularities of radiation power spectral distribution of an electron moving in a spiral in a medium has been investigated near the Cherenkov threshold. The fine structure of the electromagnetic radiation spectrum at the Cherenkov threshold and the synchrotron-Cherenkov radiation spectrum for an electron moving along a spiral with non-relativistic longitudinal component of the velocity (i.e., the component parallel to the magnetic induction vector in a transparent isotropic medium have been obtained and studied.

  12. Children with autism spectrum disorder: teaching conversation involving feelings about events.

    Science.gov (United States)

    Conallen, K; Reed, P

    2017-03-01

    Two procedures were developed to teach individuals with Autism Spectrum Disorders labels (tacts) for various private events (emotions): Study 1 attempted to distinguish them from pure tacts and mands (requests); and Study 2 attempted to train initiating a conversation with grammatically correct subject-verb-comment construction. A multiple treatment reversal design was used in both studies, followed by a probe to see if the tacts were used across novel settings. The children were prompted to initiate a series of language exchanges, which resulted in an increased ability to participate in conversations about private events. Together, the results of both studies suggest that, by providing an effective and reinforcing means of teaching both the function and the form of these tacts, conversations can be successfully initiated by children with ASD. © 2016 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

  13. Thermo-electronic solar power conversion with a parabolic concentrator

    Science.gov (United States)

    Olukunle, Olawole C.; De, Dilip K.

    2016-02-01

    We consider the energy dynamics of the power generation from the sun when the solar energy is concentrated on to the emitter of a thermo-electronic converter with the help of a parabolic mirror. We use the modified Richardson-Dushman equation. The emitter cross section is assumed to be exactly equal to the focused area at a height h from the base of the mirror to prevent loss of efficiency. We report the variation of output power with solar insolation, height h, reflectivity of the mirror, and anode temperature, initially assuming that there is no space charge effect. Our methodology allows us to predict the temperature at which the anode must be cooled in order to prevent loss of efficiency of power conversion. Novel ways of tackling the space charge problem have been discussed. The space charge effect is modeled through the introduction of a parameter f (0 solar insolation, height h, apart from radii R of the concentrator aperture and emitter, and the collector material properties. We have also considered solar thermos electronic power conversion by using single atom-layer graphene as an emitter.

  14. The Spectrometer for Internal Conversion Electrons at TRIUMF-ISAC

    Science.gov (United States)

    Smallcombe, James; Evitts, Lee; Garnsworthy, Adam; Moukaddam, Mohamad; Spice Collaboration

    2016-09-01

    SPICE (SPectrometer for Internal Conversion Electrons) is a powerful tool to measure conversion coefficients and E 0 transitions in nuclei. E 0 transition strengths, which are not accessible by gamma-ray spectroscopy, are a sparsely measured observable. Such transition strengths are particularly sensitive to nuclear shape and state mixing effects and as such are a key item of data in studying the evolution of shape coexistence. SPICE is an ancillary detector that has been commissioned for use with Radioactive Ion Beams (RIBs) at the ISAC-II facility of TRIUMF. The main feature of SPICE is high efficiency over a range of electron energies from 100 to 3500 keV, crucial for work with RIBs, and an effective reduction of beam-induced backgrounds. This is achieved with an upstream magnetic lens, a high- Z photon shield and a large-area lithium-drifted silicon detector. A major theme of the physics program will be the investigation of shape coexistence and state mixing in exotic nuclei. An overview of the main features of SPICE will be presented alongside details of the commissioning and preliminary data from the first experiment studying excited structures in 110Pd. Natural Sciences and Engineering Research Council of Canada (NSERC), Canada Foundation for Innovation (CFI), Ontario Ministry of Research and Innovation (MRI).

  15. High-Resolution Conversion Electron Spectroscopy of Valence Electron Configurations (CESVEC) in Solids

    CERN Multimedia

    2002-01-01

    First measurements with the Zurich $\\beta$-spectrometer on sources from ISOLDE have demonstrated that high resolution spectroscopy of conversion electrons from valence shells is feasible.\\\\ \\\\ This makes possible a novel type of electron spectroscopy (CESVEC) on valence-electron configurations of tracer elements in solids. Thus the density of occupied electron states of impurities in solids has been measured for the first time. Such data constitute a stringent test of state-of-the-art calculations of impurity properties. Based on these results, we are conducting a systematic investigation of impurities in group IV and III-V semiconductors.

  16. Muon conversion to electron in nuclei in type-I seesaw models

    CERN Document Server

    Alonso, Rodrigo; Gavela, M B; Hambye, Thomas

    2012-01-01

    We compute the muon to electron conversion in the type-I seesaw model, as a function of the right-handed neutrino mixings and masses. The results are compared with previous computations in the literature. We determine the definite predictions resulting for the ratios between the muon to electron conversion rate for a given nucleus and the rate of two other processes which also involve a mu-e flavour transition: mu -> e gamma and mu -> eee. For a quasi-degenerate mass spectrum of right-handed neutrino masses -which is the most natural scenario leading to observable rates- those ratios depend only on the seesaw mass scale, offering a quite interesting testing ground. In the case of sterile neutrinos heavier than the electroweak scale, these ratios vanish typically for a mass scale of order a few TeV. Furthermore, the analysis performed here is also valid down to very light masses. It turns out that planned mu -> e conversion experiments would be sensitive to masses as low as 2 MeV. Taking into account other exp...

  17. Electron Beam Spectrum Diagnostics with Optical Transition Radiation on the Beijing Free-Electron Laser

    Institute of Scientific and Technical Information of China (English)

    李泉凤; 吴频; 高建江; 吴刚

    2004-01-01

    A measurement system was developed to measure the electron beam spectrum of the Beijing free-electron laser based on the optical transition radiation (OTR). This paper describes the system, which consists of a 32-channel high resolution of 0.02% OTR detector, especially the spectrometer. The OTR angular-distribution pattern at the focal plane has two apexes, but the two apexes are smoothed out due to the electron beam energy distribution. The energy spectrum can be measured if the magnet energy resolution is higher than 0.7% to distinguish the electron beam energy distribution.

  18. Photon spectrum and polarization for high conversion coefficient in the Compton backscattering process

    Science.gov (United States)

    Potylitsyn, A. P.; Kolchuzhkin, A. M.; Strikhanov, M. N.; Strokov, S. A.

    2017-07-01

    This study looks to simulate the nonlinear Compton backscattering (CBS) process based on the Monte Carlo technique for the conversion coefficient Kc ⩾ 1 , which can be considered as the average number of photons emitted by each electron. The characteristics of the nonlinear CBS process simulated in this work are as follows: the number of absorbed photons of a laser, the distance in the laser pulse in which the electron passes between two collisions, the energy and the polarization of the emitted photon in each collision, and the polarization of the electron before and after collision. The developed approach allows us to find the spectra and polarization characteristics of the final electrons and photons. When Kc > 1 , the spin-flip processes need to be considered for a correct simulation of the polarization of the final photons and electrons for energies typical of a γ- γ collider.

  19. Electromagnetic Spectrum Analysis and Its Influence on the Photoelectric Conversion Efficiency of Solar Cells.

    Science.gov (United States)

    Hu, Kexiang; Ding, Enjie; Wangyang, Peihua; Wang, Qingkang

    2016-06-01

    The electromagnetic spectrum and the photoelectric conversion efficiency of the silicon hexagonal nanoconical hole (SiHNH) arrays based solar cells is systematically analyzed according to Rigorous Coupled Wave Analysis (RCWA) and Modal Transmission Line (MTL) theory. An ultimate efficiency of the optimized SiHNH arrays based solar cell is up to 31.92% in consideration of the absorption spectrum, 4.52% higher than that of silicon hexagonal nanoconical frustum (SiHNF) arrays. The absorption enhancement of the SiHNH arrays is due to its lower reflectance and more supported guided-mode resonances, and the enhanced ultimate efficiency is insensitive to bottom diameter (D(bot)) of nanoconical hole and the incident angle. The result provides an additional guideline for the nanostructure surface texturing fabrication design for photovoltaic applications.

  20. Electron to Muon Conversion in Low-Energy Electron-Nucleus Scattering

    CERN Document Server

    Diener, Kai-Peer O

    2004-01-01

    We present an estimate of the electron to muon conversion cross section in fixed-target elastic electron scattering. The matrix element $$ is calculated analytically in two scenarios introducing suitable approximations. We consider on the one hand side the case of three light Dirac neutrinos with CKM-type leptonic mixing and on the other hand a typical see-saw scenario. We evaluate the coulombic contribution to the scattering cross section in the limit of vanishing energy transfer to the nucleus and, thus, obtain a realistic estimate for the total conversion cross section. Although we find that in the see-saw scenario the cross section can be enhanced by as much as twenty orders of magnitude in comparison to the Dirac case, it is still not experimentally accessible.

  1. Electron Bernstein Wave Emission and Mode Conversion Physics on NSTX

    Energy Technology Data Exchange (ETDEWEB)

    Diem, S J; Caughman, J B; Efthimion, P; Kugel, H; LeBlanc, B P; Preinhaelter, J; Sabbagh, S A; Urban, J

    2008-05-21

    NSTX is a spherical tokamak (ST) that operates with ne up to 1020 m-3 and BT less than 0.6 T, cutting off low harmonic electron cyclotron (EC) emission widely used for Te measurements on conventional aspect ratio tokamaks. The electron Bernstein wave (EBW) can propagate in ST plasmas and is emitted at EC harmonics. These properties suggest thermal EBW emission (EBE) may be used for local Te measurements in the ST. Practically, a robust Te(R,t) EBE diagnostic requires EBW transmission efficiencies of > 90% for a wide range of plasma conditions. EBW emission and coupling physics were studied on NSTX with an obliquely viewing EBW to O-mode (B-X-O) diagnostic with two remotely steered antennas, coupled to absolutely calibrated radiometers. While Te(R,t) measurements with EBW emission on NSTX were possible, they were challenged by several issues. Rapid fluctuations in edge ne scale length resulted in > 20% changes in the low harmonic B-X-O transmission efficiency. Also, B-X-O transmission efficiency 2 during H-modes was observed to decay by a factor of 5-10 to less than a few percent. The B-X-O transmission behavior during H-modes was reproduced by EBE simulations that predict that EBW collisional damping can significantly reduce emission when Te < 30 eV inside the B-X-O mode conversion (MC) layer. Initial edge lithium conditioning experiments during H-modes have shown that evaporated lithium can increase Te inside the B-X-O MC layer, significantly increasing B-X-O transmission.

  2. High-Resolution Measurements of Low-Energy Conversion Electrons

    CERN Multimedia

    Gizon, A; Putaux, J

    2002-01-01

    Measurements of low-energy internal conversion electrons have been performed with high energy resolution in some N = 105 odd and odd-odd nuclei using a semi-circular spectrograph associated to a specific tape transport system. These experiments aimed to answer the following questions~: \\begin{itemize} \\item Do M3 isomeric transitions exist in $^{183}$Pt and $^{181}$Os, isotones of $^{184}$Au~? \\item Are the neutron configurations proposed to describe the isomeric and ground states of $^{184}$Au right or wrong~? \\item Does it exist an isomeric state in $^{182}$Ir, isotone of $^{181}$Os, $^{183}$Pt and $^{184}$Au~? \\item What are the spin and parity values of the excited states of $^{182}$Ir~? \\end{itemize} In $^{183}$Pt, the 35.0 keV M3 isomeric transition has been clearly observed and the reduced transition probability has been determined. The deduced hindrance factor is close to that observed in the neighbouring odd-odd $^{184}$Au nucleus. This confirms the neutron configurations previously proposed for the ...

  3. Muon-Electron Conversion in a Family Gauge Boson Model

    CERN Document Server

    Koide, Yoshio

    2016-01-01

    We study the $\\mu$-$e$ conversion in muonic atoms via an exchange of family gauge boson (FGB) $A_{2}^{\\ 1}$ in a $U(3)$ FGB model. Within the class of FGB model, we consider three types of family-number assignments for quarks. We evaluate the $\\mu$-$e$ conversion rate for various target nuclei, and find that next generation $\\mu$-$e$ conversion search experiments can cover entire energy scale of the model for all of types of the quark family-number assignments. We show that the conversion rate in the model is so sensitive to up- and down-quark mixing matrices, $U^{u}$ and $U^{d}$, where the CKM matrix is given by $V_\\text{CKM} = U^{u\\dagger} U^d$. Precise measurements of conversion rates for various target nuclei can identify not only the types of quark family-number assignments, but also each quark mixing matrix individually.

  4. Muon-electron conversion in a family gauge boson model

    Science.gov (United States)

    Koide, Yoshio; Yamanaka, Masato

    2016-11-01

    We study the μ-e conversion in muonic atoms via an exchange of family gauge boson (FGB) A21 in a U (3) FGB model. Within the class of FGB model, we consider three types of family-number assignments for quarks. We evaluate the μ-e conversion rate for various target nuclei, and find that next generation μ-e conversion search experiments can cover entire energy scale of the model for all of types of the quark family-number assignments. We show that the conversion rate in the model is so sensitive to up- and down-quark mixing matrices, Uu and Ud, where the CKM matrix is given by VCKM =Uu†Ud. Precise measurements of conversion rates for various target nuclei can identify not only the types of quark family-number assignments, but also each quark mixing matrix individually.

  5. Fe-contacts on InAs(100) and InP(100) characterised by conversion electron Mössbauer spectroscopy

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Gunnlaugsson, H.P; Weyer, G.;

    2005-01-01

    We have grown 4 nm thin films of Fe-57 on InAs(100) and InP(100) surfaces by use of MBE and studied the samples by Fe-57 conversion electron Mossbauer spectroscopy. In the case of InAs, the Mossbauer spectrum showed a sextet due to alpha-Fe and a further magnetically split component with slightly...

  6. Electron-Electron and Electron-Phonon interactions effects on the tunnel electronic spectrum of PbS quantum dots

    Science.gov (United States)

    Wang, Hongyue; Lhuillier, Emmanuel; Yu, Qian; Mottaghizadeh, Alireza; Ulysse, Christian; Zimmers, Alexandre; Dubertret, Benoit; Aubin, Herve

    2015-03-01

    We present a tunnel spectroscopy study of the electronic spectrum of single PbS Quantum Dots (QDs) trapped between nanometer-spaced electrodes, measured at low temperature T=5 K. The carrier filling of the QD can be controlled either by the drain voltage in the shell filling regime or by a gate voltage. In the empty QD, the tunnel spectrum presents the expected signature of the 8x degenerated excited levels. In the drain controlled shell filling regime, the levels degeneracies are lifted by the global electrostatic Coulomb energy of the QD; in the gate controlled shell filling regime, the levels degeneracies are lifted by the intra-Coulomb interactions. In the charged quantum dot, electron-phonons interactions lead to the apparition of Franck-Condon side bands on the single excited levels and possibly Franck Condon blockade at low energy. The sharpening of excited levels at higher gate voltage suggests that the magnitude of electron-phonon interactions is decreased upon increasing the electron filling in the quantum dot. This work was supported by the French ANR Grants 10-BLAN-0409-01, 09-BLAN-0388-01, by the Region Ile-de-France in the framework of DIM Nano-K and by China Scholarship Council.

  7. Evolution of quasistationary electron spectrum in open spherical quantum dot

    Directory of Open Access Journals (Sweden)

    M.V. Tkach

    2008-09-01

    Full Text Available The evolution of electron quasistationary spectrum in open spherical quantum dot is under study within the effective mass and rectangular potential model. Within the framework of the S-matrix model the exact solution of Schrödinger equation is obtained in general analytical form. It is shown, for the first time, that the generalized resonance energies and widths introduced as the parameters defining the probability distribution function (over the energy or quasi momentum of electron location in quantum dot, adequately characterize the evolution of its quasistationary states (contrary to the S-matrix poles in the whole range of barrier thickness: from zero (free states up to the infinity (stationary bound states are under the barrier and virtual and free states are above it.

  8. Electronic spectrum and localization of electronic states in aperiodic quantum dot chains

    Science.gov (United States)

    Korotaev, P. Yu.; Vekilov, Yu. Kh.; Kaputkina, N. E.

    2014-02-01

    The electronic energy spectra of aperiodic Thue-Morse, Rudin-Shapiro, and double-periodic quantum dot chains are investigated in the tight-binding approximation. The dependence of the spectrum on all parameters of a "mixed" aperiodic chain model is studied: the electronic energy at quantum dots and the hopping integrals. The electronic degree of localization in the chains under consideration is determined by analyzing the inverse participation ratio. Its spectral distribution and the dependence of the band-averaged degree of localization on these model parameters have been calculated. It is shown that a transition of the system's sites to a resonant state in which the degree of electron localization decreases, while an overlap between the subbands occurs in the spectrum is possible when the parameters are varied.

  9. Feasibility of In-Trap Conversion Electron Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Weissman, L.; Ames, F.; Aysto, J.; Forstner, O. [CERN, EP-Division (Switzerland); Rinta-Antila, S. [University of Jyvaeskyla, Department of Physics (Finland); Schmidt, P. [J. Gutenberg-Universitaet Mainz, Institut fuer Physik (Germany)

    2001-01-15

    We have used REXTRAP at ISOLDE to test the feasibility of in-trap electron spectroscopy. The results of calculations, experiments with various electron sources as well as a first test with trapped radioactive ions are presented.

  10. Anomalous k⊥(-8/3) spectrum in electron magnetohydrodynamic turbulence.

    Science.gov (United States)

    Meyrand, Romain; Galtier, Sébastien

    2013-12-27

    Electron magnetohydrodynamic turbulence is investigated under the presence of a relatively strong external magnetic field b0e∥ and through three-dimensional direct numerical simulations. Our study reveals the emergence of a k⊥(-8/3) scaling for the magnetic energy spectrum at scales k∥(D)≤k⊥≤k⊥(D), where k∥(D) and k⊥(D) are, respectively, the typical largest dissipative scales along and transverse to the b0 direction. Unlike standard magnetohydrodynamic, this turbulence regime is characterized by filaments of electric currents parallel to b0. The anomalous scaling is in agreement with a heuristic model in which the transfer in the parallel direction is negligible. Implications for solar wind turbulence are discussed.

  11. Measurement of Hot Electron Spectrum During the Interaction of Ultrashort Pulse UV Laser With Solid Target

    Institute of Scientific and Technical Information of China (English)

    LIYe-jun; SHANYu-sheng; ZHANGJi; ZHANGHai-feng; TANGXiu-zhang; WANGLei-jian

    2003-01-01

    The hot electron spectrum was measured using electron magnetic spectrometer through the irradiation of solid Cu target by an intense, UV (248 nm) femtosecond (440 fs) laser pulse with free pre-pulse, and the intensity of laser is 1017 W/cm2. We find the electron spectrum presents two temperatures Maxwellian distribution.

  12. The Internal Conversion Electron and Gamma Spectroscopy in the 14N + 197Au Reaction Measurements

    Science.gov (United States)

    KrXf3l, A.; Andrzejewski, J.; Perkowski, J.; Sobczak, K.; Kisielinski, M.; Kowalczyk, M.; Kownacki, J.; Korman, A.

    2008-02-01

    The first ``in-beam'' spectra of the internal conversion electrons were collected in the 197Au(14N,5n)206Rn fusion evaporation reaction by new constructed electron spectrometer. The measurements were carried out in electron-gamma and gamma-gamma coincidence mode with use of electron spectrometer coupled to OSIRIS II gamma array at Heavy Ion Laboratory (HIL) of the Warsaw University. The analysis of the data for gamma -gamma coincidence measurement disclosed new transitions in 206Rn excited nucleus. Experimentally obtained internal conversion coefficient allowed to determine multipolarity of the new observed transition in 206Rn nucleus.

  13. The future of electronic power processing and conversion

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Consoli, A.; Ferreira, J.A.

    2005-01-01

    . - A large penetration of power electronics into power systems will happen within the next 25-30 years. The main transmission grid will not be affected. The power electronics development will be in distributed generation and in the loads. - The success of the integrated starter/generator, hybrid or electric...... cars depends on political decisions more than on technological advances. However, the success of a recent Japanese hybrid car and the cost of oil could trigger the critical momentum for large-scale use of power electronics in automotive applications. - We are moving toward standardized power supply...

  14. Electronic Raman scattering and the renormalization of the electron spectrum in LuB{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Ponosov, Yu. S., E-mail: ponosov@imp.uran.ru; Streltsov, S. V., E-mail: streltsov@gmail.com [Russian Academy of Sciences, Institute of Metal Physics, Ural Branch (Russian Federation); Levchenko, A. V.; Filippov, V. B. [National Academy of Sciences of Ukraine, Frantsevich Institute of Materials Science Problems (Ukraine)

    2016-09-15

    The electronic Raman scattering in LuB{sub 12} single crystals of various isotope compositions is studied in the temperature range 10–650 K. The shape and the energy position of spectral maxima depend on the direction and magnitude of a probe wavevector, the temperature, and the excitation symmetry and remain unchanged when the isotope composition changes. Experimental spectra are compared with the spectra simulated on the basis of a calculated electronic structure. The experimental results are successfully described when the electron spectrum renormalization effects caused by electron–phonon coupling are taken into account. This confirms that the origin of the observed spectra in LuB{sub 12} is due to Raman scattering by electrons. A comparison of the calculated and experimental data makes it possible to determine the coupling constant (λ{sub ep} = 0.32) that gives the correct superconducting transition temperature.

  15. The future of electronic power processing and conversion

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Consoli, A.; Ferreira, J.A.

    2005-01-01

    building blocks for computers and other applications. The main push is for lower cost, and production technology becomes the important issue. - Demands for improved performance in a diversity of applications will stimulate R&D in power electronics in future. Intelligent control and energy management......At a workshop held on the Aeolian Islands in Sicily during May 2004 a group of academic and industry engineers from all over the world discussed the medium-and long-term future of power electronics and its applications in specific areas. The following main issues were identified and discussed....... - The demand is not for power electronic solutions but for system integration of electronic power processing. A more multidisciplinary approach is needed. - We will witness a proliferation of energy storage in systems. The technology is in place and the improvement in system performance makes it worthwhile...

  16. On the spectrum of secondary electrons emitted during nuclear $\\beta^{-}$-decay in few-electron atoms

    CERN Document Server

    Frolov, Alexei M

    2015-01-01

    Ionization of light atoms and ions during nuclear $\\beta^{-}$-decay is considered. We determine the velocity/momentum spectrum of secondary electrons emitted during nuclear $\\beta^{-}$-decay in one-electron tritium atom. The same method can be applied to describe velocity/momentum distributions of secondary electrons emitted from $\\beta^{-}$-decaying few-electron atoms and molecules.

  17. A diagnosis of bipolar spectrum disorder predicts diagnostic conversion from unipolar depression to bipolar disorder: a 5-year retrospective study.

    Science.gov (United States)

    Woo, Young Sup; Shim, In Hee; Wang, Hee-Ryung; Song, Hoo Rim; Jun, Tae-Youn; Bahk, Won-Myong

    2015-03-15

    The major aims of this study were to identify factors that may predict the diagnostic conversion from major depressive disorder (MDD) to bipolar disorder (BP) and to evaluate the predictive performance of the bipolar spectrum disorder (BPSD) diagnostic criteria. The medical records of 250 patients with a diagnosis of MDD for at least 5 years were retrospectively reviewed for this study. The diagnostic conversion from MDD to BP was observed in 18.4% of 250 MDD patients, and the diagnostic criteria for BPSD predicted this conversion with high sensitivity (0.870) and specificity (0.917). A family history of BP, antidepressant-induced mania/hypomania, brief major depressive episodes, early age of onset, antidepressant wear-off, and antidepressant resistance were also independent predictors of this conversion. This study was conducted using a retrospective design and did not include structured diagnostic interviews. The diagnostic criteria for BPSD were highly predictive of the conversion from MDD to BP, and conversion was associated with several clinical features of BPSD. Thus, the BPSD diagnostic criteria may be useful for the prediction of bipolar diathesis in MDD patients. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Dynamic Behavior and Quasi-energy Spectrum of Multiband Superlattice Bloch Electrons in Quantum Kicked Potential

    Institute of Scientific and Technical Information of China (English)

    OUYANG BiYao; ZHAO XianGeng; CHEN ShiGang; LIU Jie

    2001-01-01

    In this paper, we study the dynamic behavior and quasi-energy spectrum of multiband superlattice Bloch electrons in quantum kicked potential. We show analytically and numerically the avoided crossing and band suppression about the quasi-energy spectrum, the dynamic nonlocalization, and the electron oscillation behavior between two bands.

  19. Local electron spectrum above 100 MeV derived from gamma-ray emissivity spectra

    Science.gov (United States)

    Strong, A. W.

    1985-01-01

    Two new determinations of the local gamma-ray emmissivity spectrum are in good accord and were used to derive constraints on the local electron spectrum. The requirement for an electron intensity above 1 GeV larger than previously believed is confirmed and no low energy upturn is then needed.

  20. The principles of electronic and electromechanic power conversion a systems approach

    CERN Document Server

    Ferreira, Braham

    2013-01-01

    Teaching the principles of power electronics and electromechanical power conversion through a unique top down systems approach, The Principles of Electromechanical Power Conversion takes the role and system context of power conversion functions as the starting point. Following this approach, the text defines the building blocks of the system and describes the theory of how they exchange power with each other. The authors introduce a modern, simple approach to machines, which makes the principles of field oriented control and space vector theory approachable to undergraduate students as well as

  1. Group Teaching of Conversational Skills to Adolescents on the Autism Spectrum

    Science.gov (United States)

    Dotson, Wesley H.; Leaf, Justin B.; Sheldon, Jan B.; Sherman, James A.

    2010-01-01

    Adolescents with autism struggle with developing meaningful social relationships. Learning appropriate conversational skills can be an important first step in creating friendships. A procedure that has been effective in teaching conversational skills to typically developing adolescents is the teaching interaction procedure, which involves…

  2. Measurement of γ and conversion electron spectra following the decay of 125Sb

    Science.gov (United States)

    Sainath, M.; Venkataramaniah, K.; Sood, P. C.

    1998-12-01

    Relative intensities of γ rays and conversion electron lines in the decay of 125Sb are measured precisely using an HPGe detector and a miniorange electron spectrometer. These data are used to derive the K- and L-shell internal conversion coefficients and to deduce the multipolarities of the respective transitions. A revised level scheme is presented for 125Te incorporating 37 transitions between 13 energy levels up to an excitation energy of 675 keV. The newly established levels at 538 and 653 keV complete the hextuplet corresponding to the (s1/2⊗2+) and (d3/2⊗2+) phonon-coupled configurations.

  3. Muon to electron conversion: The COMET and Mu2e experiments

    CERN Document Server

    Litchfield, R P

    2014-01-01

    I describe the new generation of muon-to-electron conversion experiments, COMET and Mu2e, being constructed to make use of new high power pulsed muon beams a J-PARC and Fermilab respectively. A brief overview of the physics explored by the muon to electron conversion is given, followed by a description of the experimental challenges and resulting features common to the new experiments. The differences in approach between Mu2e and COMET are then highlighted, and the current schedules given.

  4. Conversion electron spectrometry of Pu isotopes with a silicon drift detector.

    Science.gov (United States)

    Pommé, S; Paepen, J; Peräjärvi, K; Turunen, J; Pöllänen, R

    2016-03-01

    An electron spectrometry set-up was built at IRMM consisting of a vacuum chamber with a moveable source holder and windowless Peltier-cooled silicon drift detector (SDD). The SDD is well suited for measuring low-energy x rays and electrons emitted from thin radioactive sources with low self-absorption. The attainable energy resolution is better than 0.5keV for electrons of 30keV. It has been used to measure the conversion electron spectra of three plutonium isotopes, i.e. (238)Pu, (239)Pu, (240)Pu, as well as (241)Am (being a decay product of (241)Pu). The obtained mixed x-ray and electron spectra are compared with spectra obtained with a close-geometry set-up using another SDD in STUK and spectra measured with a Si(Li) detector at IRMM. The potential of conversion electron spectrometry for isotopic analysis of mixed plutonium samples is investigated. With respect to the (240)Pu/(239)Pu isotopic ratio, the conversion electron peaks of both isotopes are more clearly separated than their largely overlapping peaks in alpha spectra.

  5. Radial modal dependence of the azimuthal spectrum after parametric down-conversion

    CSIR Research Space (South Africa)

    Zhang, Y

    2014-01-01

    Full Text Available The radial degrees of freedom of the biphoton states that are produced in spontaneous parametric down-conversion (SPDC) in the Laguerre-Gaussian (LG) basis are investigated, theoretically and experimentally. We calculated the theoretical azimuthal...

  6. The Conversion of CESR to Operate as the Test Accelerator, CesrTA, Part 3: Electron Cloud Diagnostics

    CERN Document Server

    Billing, M G; Crittendan, J A; Greenwald, S; Li, Y; Meller, R E; Strohman, C R; Sikora, J P; Calvey, J R; Palmer, M A

    2015-01-01

    Cornell's electron/positron storage ring (CESR) was modified over a series of accelerator shutdowns beginning in May 2008, which substantially improves its capability for research and development for particle accelerators. CESR's energy span from 1.8 to 5.6 GeV with both electrons and positrons makes it ideal for the study of a wide spectrum of accelerator physics issues and instrumentation related to present light sources and future lepton damping rings. Additionally a number of these are also relevant for the beam physics of proton accelerators. This paper is the third in a series of four describing the the conversion of CESR to the test accelerator, CesrTA. The first two papers discuss the overall plan for the conversion of the storage ring to an instrument capable of studying advanced accelerator physics issues and the details of the vacuum system upgrades. This paper focusses on the necessary development of new instrumentation, situated in four dedicated experimental regions, capable of studying such phe...

  7. Dose conversion coefficients for high-energy photons, electrons, neutrons and protons

    CERN Document Server

    Sakamoto, Y; Sato, O; Tanaka, S I; Tsuda, S; Yamaguchi, Y; Yoshizawa, N

    2003-01-01

    In the International Commission on Radiological Protection (ICRP) 1990 Recommendations, radiation weighting factors were introduced in the place of quality factors, the tissue weighting factors were revised, and effective doses and equivalent doses of each tissues and organs were defined as the protection quantities. Dose conversion coefficients for photons, electrons and neutrons based on new ICRP recommendations were cited in the ICRP Publication 74, but the energy ranges of theses data were limited and there are no data for high energy radiations produced in accelerator facilities. For the purpose of designing the high intensity proton accelerator facilities at JAERI, the dose evaluation code system of high energy radiations based on the HERMES code was developed and the dose conversion coefficients of effective dose were evaluated for photons, neutrons and protons up to 10 GeV, and electrons up to 100 GeV. The dose conversion coefficients of effective dose equivalent were also evaluated using quality fact...

  8. Synchrotron radiation-based Mössbauer spectra of {sup 174}Yb measured with internal conversion electrons

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Ryo, E-mail: masudar@rri.kyoto-u.ac.jp; Kobayashi, Yasuhiro; Kitao, Shinji; Kurokuzu, Masayuki [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Saito, Makina [Beamline Spectroscopy/Scattering Group, Elettra-Sincrotrone Trieste, S. S. 14 Km 163.5, I-34149 Trieste (Italy); Yoda, Yoshitaka [Research and Utilization Division, Japan Synchrotron Radiation Research Institute, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Mitsui, Takaya [Condensed Matter Science Division, Japan Atomic Energy Agency, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Iga, Fumitoshi [College of Science, Ibaraki University, Mito, Ibaraki, 310-8512 (Japan); Seto, Makoto [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Condensed Matter Science Division, Japan Atomic Energy Agency, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

    2014-02-24

    A detection system for synchrotron-radiation (SR)-based Mössbauer spectroscopy was developed to enhance the nuclear resonant scattering counting rate and thus increase the available nuclides. In the system, a windowless avalanche photodiode (APD) detector was combined with a vacuum cryostat to detect the internal conversion (IC) electrons and fluorescent X-rays accompanied by nuclear de-excitation. As a feasibility study, the SR-based Mössbauer spectrum using the 76.5 keV level of {sup 174}Yb was observed without {sup 174}Yb enrichment of the samples. The counting rate was five times higher than that of our previous system, and the spectrum was obtained within 10 h. This result shows that nuclear resonance events can be more efficiently detected by counting IC electrons for nuclides with high IC coefficients. Furthermore, the windowless detection system enables us to place the sample closer to the APD elements and is advantageous for nuclear resonant inelastic scattering measurements. Therefore, this detection system can not only increase the number of nuclides accessible in SR-based Mössbauer spectroscopy but also allows the nuclear resonant inelastic scattering measurements of small single crystals or enzymes with dilute probe nuclides that are difficult to measure with the previous detection system.

  9. Simulation and experimental results for the detection of conversion electrons with gas proportional scintillation counters

    CERN Document Server

    Rachinhas, P J B M; Lopes, J A M; Dias, T; Morgado, R E; Santos, J M; Stauffer, A D; Conde, C A N

    2000-01-01

    The application of gas proportional scintillation counters (GPSC) to the detection and identification of conversion electrons in the medium energy range is investigated. Experimental and Monte Carlo results are presented for the response of a xenon GPSC, filled at atmospheric pressure, to the decay of a sup 1 sup 0 sup 9 Cd source. This source emits 88.0 keV gamma-rays, e sub L =84.6 keV and e sub K =62.5 keV conversion electrons, as well as fluorescence X-rays and Auger electrons. Good agreement is found between the measured and the calculated energy spectra. The response to higher-energy electrons is investigated by Monte Carlo simulation, by considering a hypothetical GPSC filled with xenon at 10 atm and doped with the sup 1 sup 3 sup 3 sup m Xe metastable isotope. The calculated energy spectra for the absorption of the sup 1 sup 3 sup 3 sup m Xe 233.2 keV gamma-rays, e sub K =198.6 keV and e sub L =228.4 keV conversion electrons, as well as fluorescence X-rays and Auger electrons, are presented and discus...

  10. Localized bulk electron heating with ICRF mode conversion in the JET tokamak

    DEFF Research Database (Denmark)

    Mantsinen, M.J.; Mayoral, M.-L.; Eester, D. Van

    2004-01-01

    Ion cyclotron resonance frequencies (ICRF) mode conversion has been developed for localized on-axis and off-axis bulk electron heating on the JET tokamak. The fast magnetosonic waves launched from the low-field side ICRF antennas are mode-converted to short-wavelength waves on the high-field side...

  11. Reconstruction of the electron spectrum in a metal hydrogen sulfide

    Science.gov (United States)

    Kudryashov, N. A.; Kutukov, A. A.; Mazur, E. A.

    2017-01-01

    Generalized Eliashberg theory of the normal properties of a metal electron-phonon system with a non constant electron density of states has been used to study the effect of the conduction band reconstruction. The electron density of states of the metallic phase of the hydrogen sulfide renormalized by the strong electron-phonon coupling at a pressure of P = 225 GPa has been calculated. It has been found that the reconstructed conduction band contains a series of narrow energy pockets.

  12. Measuring an electron beam's orbital angular momentum spectrum

    CERN Document Server

    Grillo, incenzo; Venturi, Federico; Larocque, Hugo; Balboni, Roberto; Gazzadi, Gian Carlo; Frabboni, Stefano; Lu, Peng-Han; Mafakheri, Erfan; Bouchard, Frédéric; Dunin-Borkowski, Rafal E; Boyd, Robert W; Lavery, Martin P J; Padgett, Miles J; Karimi, Ebrahim

    2016-01-01

    Quantum complementarity states that particles, e.g. electrons, can exhibit wave-like properties such as diffraction and interference upon propagation. \\textit{Electron waves} defined by a helical wavefront are referred to as twisted electrons~\\cite{uchida:10,verbeeck:10,mcmorran:11}. These electrons are also characterised by a quantized and unbounded magnetic dipole moment parallel to their propagation direction, as they possess a net charge of $-|e|$~\\cite{bliokh:07}. When interacting with magnetic materials, the wavefunctions of twisted electrons are inherently modified~\\cite{lloyd:12b,schattschneider:14a,asenjo:14}. Such variations therefore motivate the need to analyze electron wavefunctions, especially their wavefronts, in order to obtain information regarding the material's structure~\\cite{harris:15}. Here, we propose, design, and demonstrate the performance of a device for measuring an electron's azimuthal wavefunction, i.e. its orbital angular momentum (OAM) content. Our device consists of nanoscale h...

  13. Hot-electron-based solar energy conversion with metal-semiconductor nanodiodes.

    Science.gov (United States)

    Lee, Young Keun; Lee, Hyosun; Lee, Changhwan; Hwang, Euyheon; Park, Jeong Young

    2016-06-29

    Energy dissipation at metal surfaces or interfaces between a metal and a dielectric generally results from elementary excitations, including phonons and electronic excitation, once external energy is deposited to the surface/interface during exothermic chemical processes or an electromagnetic wave incident. In this paper, we outline recent research activities to develop energy conversion devices based on hot electrons. We found that photon energy can be directly converted to hot electrons and that hot electrons flow through the interface of metal-semiconductor nanodiodes where a Schottky barrier is formed and the energy barrier is much lower than the work function of the metal. The detection of hot electron flow can be successfully measured using the photocurrent; we measured the photoyield of photoemission with incident photons-to-current conversion efficiency (IPCE). We also show that surface plasmons (i.e. the collective oscillation of conduction band electrons induced by interaction with an electromagnetic field) are excited on a rough metal surface and subsequently decay into secondary electrons, which gives rise to enhancement of the IPCE. Furthermore, the unique optical behavior of surface plasmons can be coupled with dye molecules, suggesting the possibility for producing additional channels for hot electron generation.

  14. Analysis of the low-energy electron-recoil spectrum of the CDMS experiment

    CERN Document Server

    Ahmed, Z; Arrenberg, S; Bailey, C N; Balakishiyeva, D; Baudis, L; Bauer, D A; Beaty, J; Brink, P L; Bruch, T; Bunker, R; Cabrera, B; Caldwell, D O; Cooley, J; Cushman, P; De Jongh, F; Dragowsky, M R; Duong, L; Figueroa-Feliciano, E; Filippini, J; Fritts, M; Golwala, S R; Grant, D R; Hall, J; Hennings-Yeomans, R; Hertel, S; Holmgren, D; Hsu, L; Huber, M E; Kamaev, O; Kiveni, M; Kos, M; Leman, S W; Mahapatra, R; Mandic, V; Moore, D; McCarthy, K A; Mirabolfathi, N; Nelson, H; Ogburn, R W; Pyle, M; Qiu, X; Ramberg, E; Rau, W; Reisetter, A; Saab, T; Sadoulet, B; Sander, J; Schnee, R W; Seitz, D N; Serfass, B; Sundqvist, K M; Wang, G; Yellin, S; Yoo, J; Young, B A

    2009-01-01

    We report on the analysis of the low-energy electron-recoil spectrum from the CDMS II experiment using data with an exposure of 443.2 kg-days. The analysis provides details on the observed counting rate and possible background sources in the energy range of 2 - 8.5 keV. We find no significant excess in the counting rate above background, and compare this observation to the recent DAMA results. In the framework of a conversion of a dark matter particle into electromagnetic energy, our 90% confidence level upper limit of 0.246 events/kg/day at 3.15 keV is lower than the total rate above background observed by DAMA by 8.9$\\sigma$. In absence of any specific particle physics model to provide the scaling in cross section between NaI and Ge, we assume a Z^2 scaling. With this assumption the observed rate in DAMA differs from the upper limit in CDMS by 6.8$\\sigma$. Under the conservative assumption that the modulation amplitude is 6% of the total rate we obtain upper limits on the modulation amplitude a factor of ~2...

  15. Doubly stochastic Poisson processes in EMARG with detection of. beta. particles and internal-conversion electrons emitted from a surface

    Energy Technology Data Exchange (ETDEWEB)

    Rusov, V.D.; Zelentsova, T.N.; Grechan, V.I.; Semenov, M.Y.; Kravchenko, S.N.

    1985-12-01

    The form of the counting statistics is determined for detection of ..beta.. particles and internal-conversion electrons by a nuclear emulsion. It is shown experimentally for the first time that photographic detection of ..beta.. particles and internal-conversion electrons obeys a Neyman type-A distribution, and not a Poisson distribution as was previously assumed.

  16. Electronic spectrum of the high-temperature superconducting state

    Science.gov (United States)

    Hwu, Y.; Lozzi, L.; Marsi, M.; La Rosa, S.; Winokur, M.; Davis, P.; Onellion, M.; Berger, H.; Gozzo, F.; Levy, F.

    1991-10-01

    Improved experimental conditions permitted an increase in the signal-to-noise ratio of the photoemission spectra for the superconducting state of Bi2Ca2SrCu2O8, taken with high angular and energy resolution. This also revealed a pronounced minimum that separates the two basic features of the spectrum, the narrow quasi-particle excitation peak and the controversial broad band at lower kinetic energies. The minimum is approximately 3-Delta below the Fermi level.

  17. Zeeman Effect in the Electronic Spectrum of Solid CS2

    NARCIS (Netherlands)

    Hochstrasser, Robin M.; Wiersma, Douwe A.

    1971-01-01

    The lowest-energy 3A2←1Σg+ singlet-triplet transition of CS2 has been studied in the CS2 crystal at 4.2°K. The spectrum consists mainly of progressions in the bending mode ν2'. The following values for the upper state frequencies have been obtained (v1'=677 cm–1, ν2'=309 cm–1) and the unobserved B2

  18. The electronic spectrum of cryogenic ruthenium-tris-bipyridine dications in vacuo

    Science.gov (United States)

    Xu, Shuang; Smith, James E. T.; Weber, J. Mathias

    2016-07-01

    We report the electronic spectrum of the prototypical ruthenium coordination complex Ru(bpy)32+ (bpy = 2, 2'-bipyridine) by messenger tagging with N2 in a cryogenic ion trap and photodissociation spectroscopy of mass selected Ru(bpy)32+ ṡ N2 ions. We observe individual electronic bands and groups of bands with unprecedented detail, particularly in the usually unresolved metal-to-ligand charge transfer region of the spectrum. By comparing our experimental results with time-dependent density functional theory, both with and without spin-orbit interaction [Heully et al., J. Chem. Phys. 131, 184308 (2009)], we are able to assign the spectrum of the isolated ion.

  19. Solar Modulation of 50-500 Mev Cosmic Ray Electrons and the Electron Spectrum from 1964-1994

    Science.gov (United States)

    Huber, David M.

    1998-11-01

    Cosmic ray electrons have been directly measured since 1960. Over the last four decades a wealth of data has been collected on these particles, but perhaps none as valuable as the measurements made by the University of Chicago MEH experiment on the ISEE-3/ICE spacecraft and the University of Chicago/Bartol Research Institute Low Energy Electron (LEE) balloon experiment. These data span parts of four solar cycles and cover three solar polarity reversals. The MEH dataset itself has continuous electron coverage spanning seventeen years and two polarity reversals. A new analysis has been done on the MEH dataset to determine the spectrum of electrons with energies from about 30 to 500 MeV and interpret the evolution of the spectrum in the context of the modulation of cosmic electrons over the last four solar cycles. The spectral index for electrons between 30 and 500 MeV was observed to be at all times negative between the years 1979 and 1994. This observation supports recent theoretical calculations that predict fundamental differences between the behavior of electrons and protons at low energies, namely that electrons have a much longer mean free path at low energies than previously assumed. Recent modulation calculations have focused attention on the A-positive solar polarity state, but the compilation of electron spectrum observations and calculations in this work provides a basis for future exploration of the A-negative solar cycle.

  20. Band electron spectrum and thermodynamic properties of the pseudospin-electron model with tunneling splitting of levels

    Directory of Open Access Journals (Sweden)

    O.Ya.Farenyuk

    2006-01-01

    Full Text Available The pseudospin-electron model with tunneling splitting of levels is considered. Generalization of dynamic mean-field method for systems with correlated hopping was applied to the investigation of the model. Electron spectra, electron concentrations, average values of pseudospins and grand canonical potential were calculated within the alloy-analogy approximation. Electron spectrum and dependencies of the electron concentrations on chemical potential were obtained. It was shown that in the alloy-analogy approximation, the model possesses the first order phase transition to ferromagnetic state with the change of chemical potential and the second order phase transition with the change of temperature.

  1. Spectrum

    DEFF Research Database (Denmark)

    Høgfeldt Hansen, Leif

    2016-01-01

    The publication functions as a proces description of the development and construction of an urban furniture SPECTRUM in the city of Gwangju, Republic of Korea. It is used as the cataloque for the exhibition of Spectrum.......The publication functions as a proces description of the development and construction of an urban furniture SPECTRUM in the city of Gwangju, Republic of Korea. It is used as the cataloque for the exhibition of Spectrum....

  2. Carbon Nanotube Electron Sources: From Electron Beams to Energy Conversion and Optophononics

    OpenAIRE

    Alireza Nojeh

    2014-01-01

    Carbon nanotubes have a host of properties that make them excellent candidates for electron emitters. A significant amount of research has been conducted on nanotube-based field-emitters over the past two decades, and they have been investigated for devices ranging from flat-panel displays to vacuum tubes and electron microscopes. Other electron emission mechanisms from carbon nanotubes, such as photoemission, secondary emission, and thermionic emission, have also been studied, although to a ...

  3. High-efficiency solar energy conversion with spectrum splitting prismatic lens (and other configurations)

    Science.gov (United States)

    Apostoleris, Harry; Maragliano, Carlo; Chiesa, Matteo; Stefancich, Marco

    2016-09-01

    Optical spectrum splitting systems that divide light between independent solar cells of different band gaps have received increasing attention in recent years as an alternative to expensive multijunction cells for high-efficiency PV. Most research, however, has focused on dichroic filters and other photonic structures that are expensive to manufacture. This has the effect of transferring the cost of the system from the PV cells to the optics. As a low-cost spectrum splitting approach we designed a prismatic lens that simultaneously splits and concentrates light and can be fabricated by injection molding. We present experimental results of a two-cell demonstration system, and calculations for low-cost configurations of commercial solar cells, enabled by the removal of lattice-matching requirements.

  4. The allyl radical revisited: a theoretical study of the electronic spectrum

    Science.gov (United States)

    Aquilante, Francesco; Jensen, Kasper P.; Roos, Björn O.

    2003-10-01

    In this Letter, we report the electronic spectrum of the allyl radical, obtained with multiconfigurational perturbation theory (MS-CASPT2). The assignment of the spectrum is in accordance with experiment to within 0.2 eV. We have computed the complete first Rydberg series and the beginning of the second Rydberg series. A new valence-excited 2B 1 state has been found which has hitherto been hidden by Rydberg transitions. A rationalisation of the electronic spectrum is provided in terms of resonance forms in ground and excited states. This model shows that while a multiconfigurational wavefunction is necessary to qualitatively model the system, the large ionic character of the valence electronic states makes an accurate treatment of the dynamical correlation necessary for a quantitative description of the spectrum.

  5. Direct measurement of electron beam quality conversion factors using water calorimetry.

    Science.gov (United States)

    Renaud, James; Sarfehnia, Arman; Marchant, Kristin; McEwen, Malcolm; Ross, Carl; Seuntjens, Jan

    2015-11-01

    In this work, the authors describe an electron sealed water calorimeter (ESWcal) designed to directly measure absorbed dose to water in clinical electron beams and its use to derive electron beam quality conversion factors for two ionization chamber types. A functioning calorimeter prototype was constructed in-house and used to obtain reproducible measurements in clinical accelerator-based 6, 9, 12, 16, and 20 MeV electron beams. Corrections for the radiation field perturbation due to the presence of the glass calorimeter vessel were calculated using Monte Carlo (MC) simulations. The conductive heat transfer due to dose gradients and nonwater materials was also accounted for using a commercial finite element method software package. The relative combined standard uncertainty on the ESWcal dose was estimated to be 0.50% for the 9-20 MeV beams and 1.00% for the 6 MeV beam, demonstrating that the development of a water calorimeter-based standard for electron beams over such a wide range of clinically relevant energies is feasible. The largest contributor to the uncertainty was the positioning (Type A, 0.10%-0.40%) and its influence on the perturbation correction (Type B, 0.10%-0.60%). As a preliminary validation, measurements performed with the ESWcal in a 6 MV photon beam were directly compared to results derived from the National Research Council of Canada (NRC) photon beam standard water calorimeter. These two independent devices were shown to agree well within the 0.43% combined relative uncertainty of the ESWcal for this beam type and quality. Absorbed dose electron beam quality conversion factors were measured using the ESWcal for the Exradin A12 and PTW Roos ionization chambers. The photon-electron conversion factor, kecal, for the A12 was also experimentally determined. Nonstatistically significant differences of up to 0.7% were found when compared to the calculation-based factors listed in the AAPM's TG-51 protocol. General agreement between the relative

  6. Direct measurement of electron beam quality conversion factors using water calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Renaud, James, E-mail: james.renaud@mail.mcgill.ca; Seuntjens, Jan [Medical Physics Unit, McGill University, Montréal, Québec H3G 1A4 (Canada); Sarfehnia, Arman [Medical Physics Unit, McGill University, Montréal, Québec H3G 1A4, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3E2 (Canada); Marchant, Kristin [Allan Blair Cancer Centre, Saskatchewan Cancer Agency, Regina, Saskatchewan S4T 7T1, Canada and Department of Oncology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A1 (Canada); McEwen, Malcolm; Ross, Carl [Ionizing Radiation Standards, National Research Council of Canada, Ottawa, Ontario K1A 0R6 (Canada)

    2015-11-15

    Purpose: In this work, the authors describe an electron sealed water calorimeter (ESWcal) designed to directly measure absorbed dose to water in clinical electron beams and its use to derive electron beam quality conversion factors for two ionization chamber types. Methods: A functioning calorimeter prototype was constructed in-house and used to obtain reproducible measurements in clinical accelerator-based 6, 9, 12, 16, and 20 MeV electron beams. Corrections for the radiation field perturbation due to the presence of the glass calorimeter vessel were calculated using Monte Carlo (MC) simulations. The conductive heat transfer due to dose gradients and nonwater materials was also accounted for using a commercial finite element method software package. Results: The relative combined standard uncertainty on the ESWcal dose was estimated to be 0.50% for the 9–20 MeV beams and 1.00% for the 6 MeV beam, demonstrating that the development of a water calorimeter-based standard for electron beams over such a wide range of clinically relevant energies is feasible. The largest contributor to the uncertainty was the positioning (Type A, 0.10%–0.40%) and its influence on the perturbation correction (Type B, 0.10%–0.60%). As a preliminary validation, measurements performed with the ESWcal in a 6 MV photon beam were directly compared to results derived from the National Research Council of Canada (NRC) photon beam standard water calorimeter. These two independent devices were shown to agree well within the 0.43% combined relative uncertainty of the ESWcal for this beam type and quality. Absorbed dose electron beam quality conversion factors were measured using the ESWcal for the Exradin A12 and PTW Roos ionization chambers. The photon-electron conversion factor, k{sub ecal}, for the A12 was also experimentally determined. Nonstatistically significant differences of up to 0.7% were found when compared to the calculation-based factors listed in the AAPM’s TG-51 protocol

  7. Conversion electron study of {sup 110}Cd: Evidence of new E0 branches

    Energy Technology Data Exchange (ETDEWEB)

    Jigmeddorj, B.; Garrett, P.E.; Diaz Varela, A.; Bangay, J.C.; Demand, G.A.; Green, K.L.; Rand, E.T.; Sumithrarachchi, C.; Svensson, C.E.; Wong, J. [University of Guelph, Department of Physics, Guelph, ON (Canada); Ball, G.C.; Garnsworthy, A.B.; Hackman, G. [TRIUMF, Vancouver, BC (Canada); Cross, D.S. [Simon Fraser University, Department of Chemistry, Burnaby, BC (Canada); Kulp, W.D.; Wood, J.L. [Georgia Institute of Technology, School of Physics, Atlanta, GA (United States); Leach, K.G. [University of Guelph, Department of Physics, Guelph, ON (Canada); TRIUMF, Vancouver, BC (Canada); Orce, J.N. [TRIUMF, Vancouver, BC (Canada); University of the Western Cape, Department of Physics, Bellville (South Africa); Triambak, S. [TRIUMF, Vancouver, BC (Canada); University of the Western Cape, Department of Physics, Bellville (South Africa); iThemba LABS, Somerset West (South Africa); Yates, S.W. [University of Kentucky, Departments of Chemistry and Physics and Astronomy, Lexington, KY (United States)

    2016-02-15

    Excited states of {sup 110}Cd were studied with conversion electron spectroscopy following the β{sup +}/EC decay of {sup 110}In. Internal conversion coefficients from K-shell electrons are extracted from γ - e{sup -} coincidences and compared with expected values for E1, M1, and E2 transitions, allowing the assignment of the transition multipolarities. The α{sub K} values for transitions connecting the 4{sup +} and 6{sup +} members of the deformed intruder band and the ground-state band show evidence for E0 components. The extracted ρ{sup 2}(E0).10{sup 3} value for the 4{sup +}{sub 3}→4{sup +}{sub 1} 708 keV transition is determined to be 106{sup +98}{sub -91}. (orig.)

  8. A Direct Power Electronic Conversion Topology for Multi-Drive Applications

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2002-01-01

    In this paper, a two-stage converter topology consisting of a three-phase to two-phase matrix converter directly linked to a Voltage Source Inverter (VSI) that provides Direct Power Electronic Conversion (DPEC) is analysed. A new topology for multi-drive applications is proposed where several VSI...... stages are directly linked to a rectification stage without using DC-link capacitors, providing similar performance as a matrix converter: sinusoidal input currents and bi-directional power flow....

  9. A Palladium-Binding Deltarhodopsin for Light-Activated Conversion of Protonic to Electronic Currents.

    Science.gov (United States)

    Soto-Rodríguez, Jessica; Hemmatian, Zahra; Josberger, Erik E; Rolandi, Marco; Baneyx, François

    2016-08-01

    Fusion of a palladium-binding peptide to an archaeal rhodopsin promotes intimate integration of the lipid-embedded membrane protein with a palladium hydride protonic contact. Devices fabricated with the palladium-binding deltarhodopsin enable light-activated conversion of protonic currents to electronic currents with on/off responses complete in seconds and a nearly tenfold increase in electrical signal relative to those made with the wild-type protein.

  10. Plugged In: Electronics Use in Youth and Young Adults with Autism Spectrum Disorder

    Science.gov (United States)

    MacMullin, Jennifer A.; Lunsky, Yona; Weiss, Jonathan A.

    2016-01-01

    Although electronic technology currently plays an integral role for most youth, there are growing concerns of its excessive and compulsive use. This study documents patterns and impact of electronics use in individuals with autism spectrum disorder compared to typically developing peers. Participants included 172 parents of typically developing…

  11. Perspective on the Cosmic-ray Electron Spectrum above TeV

    Science.gov (United States)

    Fang, Kun; Wang, Bing-Bing; Bi, Xiao-Jun; Lin, Su-Jie; Yin, Peng-Fei

    2017-02-01

    The AMS-02 has measured the cosmic-ray electron (plus positron) spectrum up to ∼TeV with unprecedented precision. The spectrum can be well described by a power law without any obvious features above 10 GeV. The satellite instrument Dark Matter Particle Explorer (DAMPE), which was launched a year ago, will measure the electron spectrum up to 10 TeV with high-energy resolution. The cosmic electrons beyond TeV may be attributed to few local cosmic-ray sources, such as supernova remnants. Therefore, spectral features, such as cut-off and bumps, can be expected at high energies. In this work, we provide a careful study on the perspective of the electron spectrum beyond TeV. We first examine our astrophysical source models on the latest leptonic data of AMS-02 to give a self-consistent picture. Then we focus on the discussion about the candidate sources, which could be electron contributors above TeV. Depending on the properties of the local sources (especially on the nature of Vela), DAMPE may detect interesting features in the electron spectrum above TeV in the future.

  12. Preparation of {sup 114m}In low energy conversion electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Wrede, C., E-mail: wrede@uw.ed [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 (United States); Filippone, B.W. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125 (United States); Garcia, A.; Harper, G.C. [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 (United States); Lassell, S. [Department of Nuclear Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Liu, J. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125 (United States); Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Mendenhall, M.P. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125 (United States); Palmer, A.S.C. [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 (United States); Pattie, R.W. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States); Will, D.I. [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 (United States); Young, A.R. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2011-05-15

    Highlights: {yields} Controlled ion implantation of In-113 into thin Al substrate. {yields} Production of In-114m (half life = 50 days) by neutron irradiation. {yields} Use of In-114m as a source of electron lines and continuum for calibrations. {yields} Source reactivation by short neutron irradiation. -- Abstract: The preparation of {sup 114m}In sources of conversion electrons in the energy range 162-190 keV and {beta} continuum with a 1989 keV endpoint via ion implantation of {sup 113}In into Al substrates and subsequent irradiation by thermal and epi-thermal neutrons in a nuclear reactor is described.

  13. Combined in-beam gamma-ray and conversion electron spectroscopy with radioactive ion beams

    Directory of Open Access Journals (Sweden)

    Konki J.

    2013-12-01

    Full Text Available In-beam gamma-ray and electron spectroscopy have been widely used as tools to study the broad variety of phenomena in nuclear structure. The SPEDE spectrometer is a new device to be used in conjunction with the MINIBALL germanium detector array to enable the detection of internal conversion electrons in coincidence with gamma rays from de-exciting nuclei in radioactive ion beam experiments at the upcoming HIE-ISOLDE facility at CERN, Switzerland. Geant4 simulations were carried out in order to optimise the design and segmentation of the silicon detector to achieve good energy resolution and performance.

  14. Energy Conversion Mechanism for Electron Perpendicular Energy in High Guide-Field Reconnection

    Science.gov (United States)

    Guo, Xuehan; Horiuchi, Ritoku; Kaminou, Yasuhiro; Cheng, Frank; Ono, Yasushi

    2016-10-01

    The energy conversion mechanism for electron perpendicular energy, both the thermal and the kinetic energy, is investigated by means of two-dimensional, full-particle simulations in an open system. It is shown that electron perpendicular heating is mainly due to the breaking of magnetic moment conservation in separatrix region because the charge separation generates intense variation of electric field within the electron Larmor radius. Meanwhile, electron perpendicular acceleration takes place manly due to the polarization drift term as well as the curvature drift term of E . u⊥ in the downstream near the X-point. The enhanced electric field due to the charge separation there results in a significant effect of the polarization drift term on the dissipation of magnetic energy within the ion inertia length in the downstream. Japan Society for the Promotion of Science (JSPS) Fellows 15J03758.

  15. Electronic absorption spectrum of triacetylene cation for astronomical considerations.

    Science.gov (United States)

    Chakrabarty, S; Rice, C A; Mazzotti, F J; Dietsche, R; Maier, J P

    2013-10-03

    The A(2)Πg ← X(2)Πu electronic transition (4800-6000 Å) of triacetylene cation was measured in an ion trap, where the vibrational and rotational degrees of freedom were equilibrated to 25 K. The rotational profile of the origin band is predicted by a collisional-radiative rate model under conditions expected in diffuse interstellar clouds. Variation in the density of the surrounding gas, rotational temperature, and velocity dispersion are taken into account.

  16. The Mystery of the Electronic Spectrum of Ruthenium Monophosphide

    Science.gov (United States)

    Adam, Allan G.; Christensen, Ryan M.; Dore, Jacob M.; Konder, Ricarda M.; Tokaryk, Dennis W.

    2016-06-01

    Using PH3 as a reactant gas and ruthenium as the target metal in the UNB laser ablation spectrometer, the ruthenium monophosphide molecule (RuP) has been detected. Dispersed fluorescence experiments have been performed to determine ground state vibrational frequencies and the presence of any low-lying electronic states. Rotationally resolved spectra of two vibrational bands at 577nm and 592nm have been taken; the bands have been identified as 1-0 and 0-0 bands based on isotopic shifts. Ruthenium has seven stable isotopes and rotational transitions have been observed for six of the RuP isotopologues. RuP is isoelectronic to RuN so it is expected that RuP will have a 2Σ+ ground state and low resolution spectra indicated a likely 2Σ+ - 2Σ+ electronic transition. Further investigation has led us to believe we are observing a 2Π - 2Σ+ transition but mysteriously some important rotational branches are missing. It is hoped that new data to be recorded on a second electronic system we have observed at 535nm will help shed light on this mystery.

  17. Inverted point-contact spectrum of electron-phonon interactions in arsenic homocontacts

    Science.gov (United States)

    Khotkevich, A. V.; Krasnyi, A. S.

    2016-04-01

    The point-contact (microcontact) spectra (second derivatives of the current-voltage characteristics) of As/As point homocontacts are measured at liquid helium temperatures. Inversion of the sign of the point-contact spectrum is observed as a result of the destruction of electron localization in the arsenic contacts owing to electron-phonon interactions. The point-contact spectrum contains two major peaks at energies of 10 and 25 meV. The boundary of the single-phonon part of the spectrum corresponds to 34 meV. This agrees with available data on the density of phonon states. Assuming that the inverted point-contact spectrum reflects features of the electro-phonon interaction spectral function, the mean-square frequency of the phonons is calculated and the Debye temperature is estimated.

  18. Tunable Mixed Ionic/Electronic Conductivity and Permittivity of Graphene Oxide Paper for Electrochemical Energy Conversion.

    Science.gov (United States)

    Bayer, Thomas; Bishop, Sean R; Perry, Nicola H; Sasaki, Kazunari; Lyth, Stephen M

    2016-05-11

    Graphene oxide (GO) is a two-dimensional graphitic carbon material functionalized with oxygen-containing surface functional groups. The material is of interest in energy conversion, sensing, chemical processing, gas barrier, and electronics applications. Multilayer GO paper has recently been applied as a new proton conducting membrane in low temperature fuel cells. However, a detailed understanding of the electrical/dielectric properties, including separation of the ionic vs electronic contributions under relevant operating conditions, has so far been lacking. Here, the electrical conductivity and dielectric permittivity of GO paper are investigated in situ from 30 to 120 °C, and from 0 to 100% relative humidity (RH) using impedance spectroscopy. These are related to the water content, measured by thermogravimetric analysis. With the aid of electron blocking measurements, GO is demonstrated to be a mixed electronic-protonic conductor, and the ion transference number is derived for the first time. For RH > 40%, conductivity is dominated by proton transport (with a maximum of 0.5 mS/cm at 90 °C and 100% RH). For RH proton conducting electrolyte but also as a mixed conducting electrode material under appropriate conditions. Such materials are highly applicable in electrochemical energy conversion and storage devices such as fuel cells and electrolyzers.

  19. Laser-driven micro-Coulomb charge movement and energy conversion to relativistic electrons

    Science.gov (United States)

    Cobble, J. A.; Palaniyappan, S.; Johnson, R. P.; Shimada, T.; Huang, C.; Gautier, D. C.; Clark, D. D.; Falk, K.; Jung, D.

    2016-09-01

    Development of robust instrumentation has shown evidence for a multi-μC expulsion of relativistic electrons from a sub-μm-thick foil, laser illuminated with 60-70 J on target at 2 × 1020 W/cm2. From previous work and with electron spectroscopy, it is seen that an exponential electron energy distribution is accurate enough to calculate the emitted electron charge and energy content. The 5-10-μC charge for the >100-TW Trident Laser represents the first active measurement of the >50% laser-light-to-electron conversion efficiency. By shorting out the TV/m electric field usually associated with accelerating multi-MeV ions from such targets, one finds that this charge is representative of a multi-MA current of relativistic electrons for diverse applications from electron fast ignition to advanced radiography concepts. Included with the details of the discoveries of this research, shortcomings of the diagnostics and means of improving their fidelity are discussed.

  20. Electron exchanges in nuclear spin conversion of hydrogen physisorbed on diamagnetic insulators

    Science.gov (United States)

    Ilisca, Ernest; Ghiglieno, Filippo

    2014-10-01

    Models are provided and discussed to interpret new experiments on the ortho-para conversion of hydrogen "physisorbed" on dielectric and diamagnetic surfaces. Electro-static and dynamical molecule-surface interactions complemented by hyperfine contacts are shown to be generally more effective than the magnetic ones. Coulomb repulsion induces exchanges of molecular and surface electrons and excites triplet spin states which are effective in the angular momenta transfers to the catalyst. The conversion time is obtained as the square of a ratio of two energies: the exchange and excitation ones. The main channel is found composed of triplet excitations of the order of the eV, induced by molecule-surface exchanges of about a hundred of meV. It explains the zinc and oxygen rates of about one minute observed on the MOF samples as well as the about ten times slower ones on the ASW. The same mechanism is also shown to occur in the transient regime, but faster. Finally it explains also the conversion of a few hours observed for interstitial hydrogen in silicium by transitions to the conduction band induced by about 10 meV electron exchanges. The molecule-surface orbital geometries of the MOF and ASW configurations are displayed and the quantum path when unfolded exhibits the successive broken symmetries.

  1. Influences of Uncaptured Electron on Energy Conversion of Photon Compton Scattering in High Power Laser-plasma

    Institute of Scientific and Technical Information of China (English)

    ZHENG Jing-hua; HAO Xiao-fei; HAO Dong-shan

    2004-01-01

    Using the single particle theory and the non-flexibility collision model of electron and photon, the influence of the uncaptured electrons on the energy conversion efficiency of multi-photon nonlinear Compton scattering in the extra stationary laser-plasma is investigated. It shows that in extra stationary laser-plasma,the uncaptured electrons make the Δω of the scattering frequency of the multi-photon Compton fall down with the increases of the incident radiation electron speed,the materials of the incident collision of electron and photon, and the number of the photons which work with the electrons at the same time. Under the modulation of the uncaptured electrons to the laser field, the energy conversion efficiency between electrons and photons will fall down with the increase of the electron incident radiation speed, using the low-power electrons for incident source, the loss can be efficiently reduced.

  2. Off-axis holographic lens spectrum-splitting photovoltaic system for direct and diffuse solar energy conversion.

    Science.gov (United States)

    Vorndran, Shelby D; Chrysler, Benjamin; Wheelwright, Brian; Angel, Roger; Holman, Zachary; Kostuk, Raymond

    2016-09-20

    This paper describes a high-efficiency, spectrum-splitting photovoltaic module that uses an off-axis volume holographic lens to focus and disperse incident solar illumination to a rectangular shaped high-bandgap indium gallium phosphide cell surrounded by strips of silicon cells. The holographic lens design allows efficient collection of both direct and diffuse illumination to maximize energy yield. We modeled the volume diffraction characteristics using rigorous coupled-wave analysis, and simulated system performance using nonsequential ray tracing and PV cell data from the literature. Under AM 1.5 illumination conditions the simulated module obtained a 30.6% conversion efficiency. This efficiency is a 19.7% relative improvement compared to the more efficient cell in the system (silicon). The module was also simulated under a typical meteorological year of direct and diffuse irradiance in Tucson, Arizona, and Seattle, Washington. Compared to a flat panel silicon module, the holographic spectrum splitting module obtained a relative improvement in energy yield of 17.1% in Tucson and 14.0% in Seattle. An experimental proof-of-concept volume holographic lens was also fabricated in dichromated gelatin to verify the main characteristics of the system. The lens obtained an average first-order diffraction efficiency of 85.4% across the aperture at 532 nm.

  3. Dose conversion coefficients for electron exposure of the human eye lens

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, R [Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig (Germany); Dietze, G [Paracelsusstrasse 7, D-38116 Braunschweig (Germany); Zankl, M [Helmholtz Zentrum Muenchen, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)], E-mail: rolf.behrens@ptb.de

    2009-07-07

    Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. Two questions arise from this situation: first, which dose quantity is related to the risk of developing a cataract, and second, which personal dose equivalent quantity is appropriate for monitoring this dose quantity. While the dose equivalent quantity H{sub p}(0.07) has often been seen as being sufficiently accurate for monitoring the dose to the lens of the eye, this would be questionable in the case when the dose limits were reduced and, thus, it may be necessary to generally use the dose equivalent quantity H{sub p}(3) for this purpose. The basis for a decision, however, must be the knowledge of accurate conversion coefficients from fluence to equivalent dose to the lens. This is especially important for low-penetrating radiation, for example, electrons. Formerly published values of conversion coefficients are based on quite simple models of the eye. In this paper, quite a sophisticated model of the eye including the inner structure of the lens was used for the calculations and precise conversion coefficients for electrons with energies between 0.2 MeV and 12 MeV, and for angles of radiation incidence between 0 deg. and 45 deg. are presented. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are up to 1000 times smaller for electron energies below 1 MeV, nearly equal at 1 MeV and above 4 MeV, and by a factor of 1.5 larger at about 1.5 MeV electron energy.

  4. Dose conversion coefficients for electron exposure of the human eye lens

    Science.gov (United States)

    Behrens, R.; Dietze, G.; Zankl, M.

    2009-07-01

    Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. Two questions arise from this situation: first, which dose quantity is related to the risk of developing a cataract, and second, which personal dose equivalent quantity is appropriate for monitoring this dose quantity. While the dose equivalent quantity Hp(0.07) has often been seen as being sufficiently accurate for monitoring the dose to the lens of the eye, this would be questionable in the case when the dose limits were reduced and, thus, it may be necessary to generally use the dose equivalent quantity Hp(3) for this purpose. The basis for a decision, however, must be the knowledge of accurate conversion coefficients from fluence to equivalent dose to the lens. This is especially important for low-penetrating radiation, for example, electrons. Formerly published values of conversion coefficients are based on quite simple models of the eye. In this paper, quite a sophisticated model of the eye including the inner structure of the lens was used for the calculations and precise conversion coefficients for electrons with energies between 0.2 MeV and 12 MeV, and for angles of radiation incidence between 0° and 45° are presented. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are up to 1000 times smaller for electron energies below 1 MeV, nearly equal at 1 MeV and above 4 MeV, and by a factor of 1.5 larger at about 1.5 MeV electron energy.

  5. Numerical experiments on the detailed energy conversion and spectrum studies in a corona current sheet

    CERN Document Server

    Ni, Lei; Mei, Zhixing; Li, Yan

    2015-01-01

    In this paper, we study the energy conversion and spectra in a corona current sheet by 2.5-dimensional MHD numerical simulations. Numerical results show that many Petschek-like fine structures with slow-mode shocks mediated by plasmoid instabilities develop during the magnetic reconnection process. The termination shocks can also be formed above the primary magnetic island and at the head of secondary islands. These shocks play important roles in generating thermal energy in a corona current sheet. For a numerical simulation with initial conditions close to the solar corona environment, the ratio of the generated thermal energy to the total dissipated magnetic energy is around $1/5$ before secondary islands appear. After secondary islands appear, the generated thermal energy starts to increase sharply and this ratio can reach a value about $3/5$. In an environment with a relatively lower plasma density and plasma $\\beta$, the plasma can be heated to a much higher temperature. After secondary islands appear, t...

  6. Spin-electron acoustic waves: The Landau damping and ion contribution in the spectrum

    CERN Document Server

    Andreev, Pavel A

    2014-01-01

    Separated spin-up and spin-down quantum kinetics is derived for more detailed research of the spin-electron acoustic waves. Kinetic theory allows to obtain spectrum of the spin-electron acoustic waves including effects of occupation of quantum states more accurately than quantum hydrodynamics. We apply quantum kinetic to calculate the Landau damping of the spin-electron acoustic waves. We have considered contribution of ions dynamics in the spin-electron acoustic wave spectrum. We obtain contribution of ions in the Landau damping in temperature regime of classic ions. Kinetic analysis for ion-acoustic, zero sound, and Langmuir waves at separated spin-up and spin-down electron dynamics is presented as well.

  7. Conversion from Single Photon to Single Electron Spin Using Electrically Controllable Quantum Dots

    Science.gov (United States)

    Oiwa, Akira; Fujita, Takafumi; Kiyama, Haruki; Allison, Giles; Ludwig, Arne; Wieck, Andreas D.; Tarucha, Seigo

    2017-01-01

    Polarization is a fundamental property of light and could provide various solutions to the development of secure optical communications with high capacity and high speed. In particular, the coherent quantum state conversion between single photons and single electron spins is a prerequisite for long-distance quantum communications and distributed quantum computation. Electrically defined quantum dots have already been proven to be suitable for scalable solid state qubits by demonstrations of single-spin coherent manipulations and two-qubit gate operations. Thus, their capacity for quantum information technologies would be considerably extended by the achievement of entanglement between an electron spin in the quantum dots and a photon. In this review paper, we show the basic technologies for trapping single electrons generated by single photons in quantum dots and for detecting their spins using the Pauli effect with sensitive charge sensors.

  8. Angular dependence, blackness and polarization effects in integral conversion electron Mössbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sajti, Sz., E-mail: sajti.szilard@wigner.mta.hu; Tanczikó, F.; Deák, L.; Nagy, D.L.; Bottyán, L.

    2015-01-01

    General expressions of the electron yield in {sup 57}Fe integral conversion electron Mössbauer spectroscopy were derived depending on the glancing angle of the γ photons, on the source polarization and on the isotopic abundance of the source and the absorber (blackness effects) using an exponential escape function of the electrons originating from all Mössbauer-resonance-related processes. The present approach provides a firm theoretical basis to determine the alignment and direction of magnetization in the absorber. The intensity formulae were justified by least squares fits of α-{sup 57}Fe spectral intensities measured in linearly and elliptically polarized source and absorber geometries. The fits reproduce the experimentally set angles with high accuracy. Limits of the current approach and its relation to other, less complete treatments in the literature are discussed.

  9. Low-energy internal conversion electrons spectrometry with a silicon diode

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Thiago R. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Inst. de Fisica; Camargo, Fabio de; Goncalves, Josemary A.C. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mail: fcamargo@ipen.br; josemary@ipen.br; ccbueno@ipen.br; Bueno, Carmen C. [Pontificia Universidade Catolica de Sao Paulo (PUC/SP), Sao Paulo, SP (Brazil). Dept. de Fisica; Fraga, Margarida R.F. [Universidade de Coimbra, Coimbra (Portugal). Dept. de Fisica. Lab. de Instrumentacao e Fisica Experimental de Particulas]. E-mail: margarida@lipc.fis.uc.pt

    2007-07-01

    In this paper the preliminary results obtained with a PIN photodiode (SFH00206) for the detection and spectrometry of internal results from {sup 57}Co, {sup 109}Cd and {sup 133}Ba radioactive sources are described. The effect of the reverse bias on the energy resolution was studied and has shown a value of 2.8 keV (FHWM) for the {sup 57}Co 129.36 keV electron emission, when the diode was biased with 20 V at a temperature of 22 degree C. The obtained energy resolution can be attributed to both the energy loss in the diode dead layer and in the Makrofol covering of the sources, besides the contribution of the preamplifier electronic noise. Nevertheless, the energy resolutions measured are sufficiently good to justify the use of the diode for detection and spectrometry of internal conversion electrons. (author)

  10. Non-equilibrium electron features in X-ray emission spectrum from inertial confinement fusion implosions

    Science.gov (United States)

    Kagan, Grigory; Landen, O. L.; Svyatsky, D.; Thorn, D.; Schneider, M. B.; Bradley, D.; Kilkenny, J. D.

    2016-10-01

    An X-ray spectrometer proposed for the National Ignition Facility will infer the imploded core electron temperature from the free-free continuum spectra of the emitted photons with energies of 15 to 30 keV. In this range reabsorption rates are low so one might expect a rather unambiguous temperature measurement from the spectrum slope at the higher energy cut-off. It can be noticed, however, that the harder X-ray radiation is emitted by the tail of the electron distribution. The mean- free-path for the suprathermal electrons is much larger than for their thermal counterparts, making this tail to deviate from Maxwellian and obscuring interpretation of the data. We utilize solutions for the reduced kinetic equation to investigate modification to the X-ray spectra due to suprathermal electrons' deviation from equilibrium. The logarithmic slope of the spectrum from the depleted electron distribution is found to increasingly drop at higher photon energies compared to the case of perfectly Maxwellian electrons. Interpreting the spectrum from a depleted distribution with assumption of Maxwellian electrons enforced gives the electron temperature lower than the actual one. The newly predicted effects are further enhanced in the presence of hydrodynamic mix. This work is performed under the auspices of the U.S. Department of Energy by the Los Alamos National Security, LLC, Los Alamos National Laboratory under Contract No. DE-AC52-06NA25396.

  11. Importance and Challenges of Electrochemical in Situ Liquid Cell Electron Microscopy for Energy Conversion Research.

    Science.gov (United States)

    Hodnik, Nejc; Dehm, Gerhard; Mayrhofer, Karl J J

    2016-09-20

    The foreseeable worldwide energy and environmental challenges demand renewable alternative sources, energy conversion, and storage technologies. Therefore, electrochemical energy conversion devices like fuel cells, electrolyzes, and supercapacitors along with photoelectrochemical devices and batteries have high potential to become increasingly important in the near future. Catalytic performance in electrochemical energy conversion results from the tailored properties of complex nanometer-sized metal and metal oxide particles, as well as support nanostructures. Exposed facets, surface defects, and other structural and compositional features of the catalyst nanoparticles affect the electrocatalytic performance to varying degrees. The characterization of the nanometer-size and atomic regime of electrocatalysts and its evolution over time are therefore paramount for an improved understanding and significant optimization of such important technologies like electrolyzers or fuel cells. Transmission electron microscopy (TEM) and scanning transmission electron microscope (STEM) are to a great extent nondestructive characterization tools that provide structural, morphological, and compositional information with nanoscale or even atomic resolution. Due to recent marked advancement in electron microscopy equipment such as aberration corrections and monochromators, such insightful information is now accessible in many institutions around the world and provides huge benefit to everyone using electron microscopy characterization in general. Classical ex situ TEM characterization of random catalyst locations however suffers from two limitations regarding catalysis. First, the necessary low operation pressures in the range of 10(-6) to 10(-9) mbar for TEM are not in line with typical reaction conditions, especially considering electrocatalytic solid-liquid interfaces, so that the active state cannot be assessed. Second, and somewhat related, is the lack of time resolution for the

  12. The H.E.S.S. measurement of the cosmic-ray electron spectrum

    Science.gov (United States)

    Egberts, Kathrin; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Barres de Almeida, U.; Bazer-Bachi, A. R.; Becherini, Y.; Behera, B.; Bernlühr, K.; Bochow, A.; Boisson, C.; Bolmont, J.; Borrel, V.; Brucker, J.; Brun, F.; Brun, P.; Bühler, R.; Bulik, T.; Büsching, I.; Boutelier, T.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Conrad, J.; Chounet, L.-M.; Clapson, A. C.; Coignet, G.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Domainko, A. Djannati-Ataü W.; Drury, L. O'c.; Dubois, F.; Dubus, G.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fiasson, A.; Fürster, A.; Fontaine, G.; Füssling, M.; Gabici, S.; Gallant, Y. A.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Goret, P.; Güring, D.; Hampf, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Hofverberg, P.; Holleran, M.; Hoppe, S.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jung, I.; Katarzynski, K.; Katz, U.; Kaufmann, S.; Kerschhaggl, M.; Khangulyan, D.; Khálifi, B.; Keogh, D.; Klochkov, D.; Kluzniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Lamanna, G.; Lenain, J.-P.; Lohse, T.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maurin, D.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Moderski, R.; Moulin, E.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nguyen, N.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; Olive, J.-F.; de Ona Wilhelmi, E.; Opitz, B.; Orford, K. J.; Ostrowski, M.; Panter, M.; Paz Arribas, M.; Pedaletti, G.; Pelletier, G.; Petrucci, P.-O.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raubenheimer, B. C.; Raue, M.; Rayner, S. M.; Reimer, O.; Renaud, M.; de Los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Ruppel, J.; Ryde, F.; Sahakian, V.; Santangelo, A.; Schlickeiser, R.; Schück, F. M.; Schünwald, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Shalchi, A.; Sushch, I.; Sikora, M.; Skilton, J. L.; Sol, H.; Stawarz, L.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Szostek, A.; Tam, P. H.; Tavernet, J.-P.; Terrier, R.; Tibolla, O.; Tluczykont, M.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Venter, L.; Vialle, J. P.; Viana, A.; Vincent, P.; Vivier, M.; Vülk, H. J.; Volpe, F.; Vorobiov, S.; Wagner, S. J.; Ward, M.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.

    The measurement of very-high-energy cosmic-ray electrons is intrinsically difficult due to their very steep spectrum with low fluxes and an enormous background of hadronic cosmic rays. The large collection areas needed for such a measurement can be provided by ground-based imaging atmospheric Cherenkov telescopes. The High Energy Stereoscopic System (H.E.S.S.) has performed the first ground-based cosmic-ray electron measurement and thereby extended the measured range of the spectrum to several TeV.

  13. Electronic structure and UV spectrum of fenofibrate in solutions.

    Science.gov (United States)

    Le, Yuan; Chen, Jian-Feng; Pu, Min

    2008-06-24

    The structure and UV spectra of fenofibrate have been evaluated in gas phase and in solutions using time dependent density functional theory (TDDFT) method at the B3LYP/6-31G(d), B3LYP/6-311G(d,p) and B3LYP/6-311++G(d,p) levels. The solvent effects have been taken into account based on the polarizable continuum model (PCM). The computed results appear that the introduction of dielectric medium has slight effect on the molecular geometry of fenofibrate. There is one allowed excited state presenting the strongest oscillator strength in the UV region, which is associated with the HOMO-->LUMO and HOMO-1-->LUMO transition both in gas phase and in solutions. The prediction of the lambda(max) in THF, ethanol and DMSO is 285 nm, 286 nm and 287 nm, respectively, which are in a good agreement with experimental data of 284 nm, 285 nm and 288 nm. The results demonstrate that TDDFT-PCM is a useful tool for study of the electronic absorption in solutions.

  14. Ab initio calculation of the electronic absorption spectrum of liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Martiniano, Hugo F. M. C.; Galamba, Nuno [Grupo de Física Matemática da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa (Portugal); Cabral, Benedito J. Costa, E-mail: ben@cii.fc.ul.pt [Grupo de Física Matemática da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa (Portugal); Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Instituto de Física da Universidade de São Paulo, CP 66318, 05314-970 São Paulo, SP (Brazil)

    2014-04-28

    The electronic absorption spectrum of liquid water was investigated by coupling a one-body energy decomposition scheme to configurations generated by classical and Born-Oppenheimer Molecular Dynamics (BOMD). A Frenkel exciton Hamiltonian formalism was adopted and the excitation energies in the liquid phase were calculated with the equation of motion coupled cluster with single and double excitations method. Molecular dynamics configurations were generated by different approaches. Classical MD were carried out with the TIP4P-Ew and AMOEBA force fields. The BLYP and BLYP-D3 exchange-correlation functionals were used in BOMD. Theoretical and experimental results for the electronic absorption spectrum of liquid water are in good agreement. Emphasis is placed on the relationship between the structure of liquid water predicted by the different models and the electronic absorption spectrum. The theoretical gas to liquid phase blue-shift of the peak positions of the electronic absorption spectrum is in good agreement with experiment. The overall shift is determined by a competition between the O–H stretching of the water monomer in liquid water that leads to a red-shift and polarization effects that induce a blue-shift. The results illustrate the importance of coupling many-body energy decomposition schemes to molecular dynamics configurations to carry out ab initio calculations of the electronic properties in liquid phase.

  15. Perspective on the cosmic-ray electron spectrum above TeV

    CERN Document Server

    Fang, Kun; Bi, Xiao-Jun; Lin, Su-Jie; Yin, Peng-Fei

    2016-01-01

    The AMS-02 has measured the cosmic ray electron (plus positron) spectrum up to ~TeV with an unprecedent precision. The spectrum can be well described by a power law without any obvious features above 10 GeV. The satellite instrument Dark Matter Particle Explorer (DAMPE), which was launched a year ago, will measure the electron spectrum up to 10 TeV with a high energy resolution. The cosmic electrons beyond TeV may be attributed to few local cosmic ray sources, such as supernova remnants. Therefore, spectral features, such as cutoff and bumps, can be expected at high energies. In this work we give a careful study on the perspective of the electron spectrum beyond TeV. We first examine our astrophysical source models on the latest leptonic data of AMS-02 to give a self-consistent picture. Then we focus on the discussion about the candidate sources which could be electron contributors above TeV. Depending on the properties of the local sources (especially on the nature of Vela), DAMPE may detect interesting feat...

  16. Time-resolved electron spectrum diagnostics for a free-electron laser

    NARCIS (Netherlands)

    Gillespie, W. A.; MacLeod, A. M.; Martin, P. F.; van der Meer, A. F. G.; van Amersfoort, P. W.

    1996-01-01

    Time-resolved electron-beam diagnostics have been developed for use with free-electron lasers (FELs) and associated electron sources, based on the techniques of secondary electron emission and optical transition radiation (OTR). The 32-channel OTR detector forms part of a high-resolution (0.18%) ele

  17. The KLM + KLN Auger electron spectrum of rubidium in different matrices

    Science.gov (United States)

    Inoyatov, A. Kh; Kovalík, A.; Perevoshchikov, L. L.; Filosofov, D. V.; Vénos, D.; Lee, B. Q.; Ekman, J.; Baimukhanova, A.

    2017-08-01

    The KLM + KLN Auger electron spectrum of rubidium (Z = 37) emitted in the electron capture decay of radioactive 83Sr in a polycrystalline platinum matrix and also 85Sr in polycrystalline platinum and carbon matrices as well as in an evaporated layer onto a carbon backing were experimentally studied in detail for the first time using a combined electrostatic electron spectrometer. Energies, relative intensities, and natural widths of fifteen basic spectrum components were determined and compared with both theoretical predictions and experimental data for krypton (Z = 36). Relative spectrum line energies obtained from the semi-empirical calculations in intermediate coupling scheme were found to agree within 3σ with the measured values while disagreement with experiment exceeding 3σ was often observed for values obtained from our multiconfiguration Dirac-Hartree-Fock calculations. The absolute energy of the dominant spectrum component given by the semi-empirical approach agrees within 1σ with the measured value. Shifts of +(0.2 ± 0.2) and -(1.9 ± 0.2) eV were measured for the dominant KLM spectrum components between the 85Sr sources prepared by vacuum evaporation on and implanted into the carbon foil, respectively, relative to 85Sr implanted into the platinum foil. A value of (713 ± 2) eV was determined for the energy difference of the dominant components of the KLM + KLN Auger electron spectra of rubidium and krypton generated in the polycrystalline platinum matrix. From the detailed analysis of the measured data and available theoretical results, the general conclusion can be drawn that the proper description of the KLM + KLN Auger electron spectrum for Z around 37 should still be based on the intermediate coupling of angular momenta taking into account relativistic effects.

  18. Electronic and vibrational spectroscopy of intermediates in methane-to-methanol conversion by CoO+

    Science.gov (United States)

    Altinay, Gokhan; Kocak, Abdulkadir; Silva Daluz, Jennifer; Metz, Ricardo B.

    2011-08-01

    At room temperature, cobalt oxide cations directly convert methane to methanol with high selectivity but very low efficiency. Two potential intermediates of this reaction, the [HO-Co-CH3]+ insertion intermediate and [H2O-Co=CH2]+ aquo-carbene complex are produced in a laser ablation source and characterized by electronic and vibrational spectroscopy. Reaction of laser-ablated cobalt cations with different organic precursors seeded in a carrier gas produces the intermediates, which subsequently expand into vacuum and cool. Ions are extracted into a time-of-flight mass spectrometer and spectra are measured via photofragment spectroscopy. Photodissociation of [HO-Co-CH3]+ in the visible and via infrared multiple photon dissociation (IRMPD) makes only Co+ + CH3OH, while photodissociation of [H2O-Co=CH2]+ produces CoCH2+ + H2O. The electronic spectrum of [HO-Co-CH3]+ shows progressions in the excited state Co-C stretch (335 cm-1) and O-Co-C bend (90 cm-1); the IRMPD spectrum gives νOH = 3630 cm-1. The [HO-Co-CH3]+(Ar) complex has been synthesized and its vibrational spectrum measured in the O-H stretching region. The resulting spectrum is sharper than that obtained via IRMPD and gives νOH = 3642 cm-1. Also, an improved potential energy surface for the reaction of CoO+ with methane has been developed using single point energies calculated by the CBS-QB3 method for reactants, intermediates, transition states and products.

  19. Energy spectrum of the electrons accelerated by reconnection electric field: exponential or power-law?

    CERN Document Server

    Liu, W J; Ding, M D; Fang, C

    2008-01-01

    The direct current (DC) electric field near the reconnection region has been proposed as an effective mechanism to accelerate protons and electrons in solar flares. A power-law energy spectrum was generally claimed in the simulations of electron acceleration by the reconnection electric field. However, in most of the literature, the electric and magnetic fields were chosen independently. In this paper, we perform test particle simulations of electron acceleration in reconnecting magnetic field, where both the electric and magnetic fields are adopted from numerical simulations of the MHD equations. It is found that the accelerated electrons present a truncated power-law energy spectrum with an exponential tail at high energies, which is analogous to the case of diffusive shock acceleration. The influences of the reconnection parameters on the spectral feature are also investigated, such as the longitudinal and transverse components of the magnetic field and the size of the current sheet. It is suggested that t...

  20. Mode conversion and electron heating near the upper hybrid resonance frequency

    Energy Technology Data Exchange (ETDEWEB)

    Smith, B.L.; Okuda, H.; Abe, H.

    1983-11-01

    Mode conversion near the upper hybrid resonance frequency and electron heating are studied using a one-dimensional electromagnetic relativistic particle code. It is found that for a sufficiently small pump field E/sub 0/, E/sub 0//sup 2//4..pi..nT/sub e/ less than or equal to 0.01, electron heating is localized in a region near the electron cyclotron layer where the pump frequency is equal to the local electron gyrofrequency. For stronger pump fields, electron heating takes place more or less uniformly across a region between the upper hybrid resonance layer and the cyclotron layer. In addition, a significant fraction of electromagnetic energy associated with the pump is found to be reflected back into the vacuum from a region in the plasma near the upper hybrid resonance layer for both strong (E/sub 0//sup 2//4..pi..nT/sub e/ approx. = 1) and weak pumps (E/sub 0//sup 2//4..pi..nT/sub e/ << 1).

  1. Watching the dynamics of electrons and atoms at work in solar energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Canton, S. E.; Zhang, X.; Liu, Y.; Zhang, J.; Pápai, M.; Corani, A.; Smeigh, A. L.; Smolentsev, G.; Attenkofer, K.; Jennings, G.; Kurtz, C. A.; Li, F.; Harlang, T.; Vithanage, D.; Chabera, P.; Bordage, A.; Sun, L.; Ott, S.; Wärnmark, K.; Sundström, V.

    2015-07-06

    The photochemical reactions performed by transition metal complexes have been proposed as viable routes towards solar energy conversion and storage into other forms that can be conveniently used in our everyday applications. In order to develop efficient materials, it is necessary to identify, characterize and optimize the elementary steps of the entire process on the atomic scale. To this end, we have studied the photoinduced electronic and structural dynamics in two heterobimetallic ruthenium–cobalt dyads, which belong to the large family of donor–bridge–acceptor systems. Using a combination of ultrafast optical and X-ray absorption spectroscopies, we can clock the light-driven electron transfer processes with element and spin sensitivity. In addition, the changes in local structure around the two metal centers are monitored. These experiments show that the nature of the connecting bridge is decisive for controlling the forward and the backward electron transfer rates, a result supported by quantum chemistry calculations. More generally, this work illustrates how ultrafast optical and X-ray techniques can disentangle the influence of spin, electronic and nuclear factors on the intramolecular electron transfer process. Finally, some implications for further improving the design of bridged sensitizer-catalysts utilizing the presented methodology are outlined.

  2. Watching the dynamics of electrons and atoms at work in solar energy conversion.

    Science.gov (United States)

    Canton, S E; Zhang, X; Liu, Y; Zhang, J; Pápai, M; Corani, A; Smeigh, A L; Smolentsev, G; Attenkofer, K; Jennings, G; Kurtz, C A; Li, F; Harlang, T; Vithanage, D; Chabera, P; Bordage, A; Sun, L; Ott, S; Wärnmark, K; Sundström, V

    2015-01-01

    The photochemical reactions performed by transition metal complexes have been proposed as viable routes towards solar energy conversion and storage into other forms that can be conveniently used in our everyday applications. In order to develop efficient materials, it is necessary to identify, characterize and optimize the elementary steps of the entire process on the atomic scale. To this end, we have studied the photoinduced electronic and structural dynamics in two heterobimetallic ruthenium-cobalt dyads, which belong to the large family of donor-bridge-acceptor systems. Using a combination of ultrafast optical and X-ray absorption spectroscopies, we can clock the light-driven electron transfer processes with element and spin sensitivity. In addition, the changes in local structure around the two metal centers are monitored. These experiments show that the nature of the connecting bridge is decisive for controlling the forward and the backward electron transfer rates, a result supported by quantum chemistry calculations. More generally, this work illustrates how ultrafast optical and X-ray techniques can disentangle the influence of spin, electronic and nuclear factors on the intramolecular electron transfer process. Finally, some implications for further improving the design of bridged sensitizer-catalysts utilizing the presented methodology are outlined.

  3. Optical absorption spectrum and electronic structure of multiferroic hexagonal YMnO3 compound

    Science.gov (United States)

    Lima, A. F.; Lalic, M. V.

    2017-02-01

    Optical absorption (OA) spectrum and electronic structure of the hexagonal YMnO3 compound have been investigated by employment of the first-principles calculations based on density functional theory. The calculations were performed upon the ferroelectric structure of the YMnO3, by testing various approximations of the exchange-correlation effects between the Mn d-electrons and considering two types of magnetic ordering of the Mn sub-lattice: (1) collinear anti-ferromagnetic order of the G-type and (2) non-collinear antiferromagnetic order that correspond to magnetic space group P63. The results demonstrate that satisfactory agreement between the theoretical and the experimental OA spectrum can be achieved only if both non-collinear anti-ferromagnetic order of the Mn spins and strong correlations between the Mn d-electrons are taken into account. The latter is found to be best described by effective Hubbard parameter Ueff = 2.55 eV. The principal features of the OA spectrum are interpreted in terms of calculated electronic structure. It is found that the most important, threshold 1.6 eV OA peak is generated by electron transitions from strongly hybridized occupied Mn d- and its neighboring in-plane O p-states to unoccupied Mn d-states. It is also concluded that the electronic gap (calculated as ∼1.1 eV) should be smaller than the optical one (∼1.6 eV).

  4. Conversion of stacking fault tetrahedra to voids in electron irradiated Fe-Cr-Ni

    Science.gov (United States)

    Kojima, S.; Sano, Y.; Yoshiie, T.; Yoshida, N.; Kiritani, M.

    1986-11-01

    Electron irradiations of the austenitic Fe-13Cr-14Ni alloy were performed with a high voltage electron microscope at temperatures between room temperature and 650 K. Formation of stacking fault tetrahedra, voids and dislocation loops was observed as vacancy clusters. At the lower temperatures, the dominant vacancy clusters were tetrahedra and at the higher temperatures, voids were dominant. In the temperature range at which both tetrahedra and voids were coexistent, conversion of tetrahedra to voids were observed. These results are interpreted as the preferable nucleation of voids at the site of tetrahedra. Local effects of dilatation field at the corner of tetrahedra and the segregation of solute atoms are considered to enhance the nucleation. Clustered defects which are considered to be stacking fault tetrahedra that are formed with D-T fusion neutrons in SUS 316 stainless steel are suggested as the preferable site for void nucleation.

  5. Measurement of the inclusive electron spectrum from B meson decays and determination of |Vub|

    CERN Document Server

    ,

    2016-01-01

    Based on the full BaBar data sample of 466.5 million BBbar pairs, we present measurements of the electron spectrum from semileptonic B meson decays. We fit the inclusive electron spectrum to distinguish CKM suppressed B -> Xu e nu decays from the CKM favored B -> Xc e nu decays, and from various other backgrounds, and determine the total semileptonic branching fraction BR(B -> X e nu) = (10.34 +- 0.04_stat +- 0.26_syst)%, averaged over B+- and B0 mesons. We determine the spectrum and branching fraction for charmless B -> Xu e nu decays and extract the CKM element |Vub|, by relying on four different QCD calculations based on the Heavy Quark Expansion. While experimentally, the electron momentum region above 2.1GeV/c is favored, because the background is relatively low, the uncertainties for the theoretical predictions are largest in the region near the kinematic endpoint. Detailed studies to assess the impact of these four predictions on the measurements of the electron spectrum, the branching fraction, and th...

  6. Calculation of the spectrum of quasiparticle electron excitations in organic molecular semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Tikhonov, E. V., E-mail: tikhonov@mig.phys.msu.ru [Moscow State University (Russian Federation); Uspenskii, Yu. A. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Khokhlov, D. R. [Moscow State University (Russian Federation)

    2015-06-15

    A quasiparticle electronic spectrum belongs to the characteristics of nanoobjects that are most important for applications. The following methods of calculating the electronic spectrum are analyzed: the Kohn-Sham equations of the density functional theory (DFT), the hybrid functional method, the GW approximation, and the Lehmann approximation used in the spectral representation of one-electron Green’s function. The results of these approaches are compared with the data of photoemission measurements of benzene, PTCDA, and phthalocyanine (CuPc, H{sub 2}Pc, FePc, PtPc) molecules, which are typical representatives of organic molecular semiconductors (OMS). This comparison demonstrates that the Kohn-Sham equations of DFT incorrectly reproduce the electronic spectrum of OMS. The hybrid functional method correctly describes the spectrum of the valence and conduction bands; however, the HOMO-LUMO gap width is significantly underestimated. The correct gap width is obtained in both the GW approximation and the Lehmann approach, and the total energy in this approach can be calculated in the local density approximation of DFT.

  7. Validation of Autism Spectrum Disorder Diagnoses in Large Healthcare Systems with Electronic Medical Records

    Science.gov (United States)

    Coleman, Karen J.; Lutsky, Marta A.; Yau, Vincent; Qian, Yinge; Pomichowski, Magdalena E.; Crawford, Phillip M.; Lynch, Frances L.; Madden, Jeanne M.; Owen-Smith, Ashli; Pearson, John A.; Pearson, Kathryn A.; Rusinak, Donna; Quinn, Virginia P.; Croen, Lisa A.

    2015-01-01

    To identify factors associated with valid Autism Spectrum Disorder (ASD) diagnoses from electronic sources in large healthcare systems. We examined 1,272 charts from ASD diagnosed youth <18 years old. Expert reviewers classified diagnoses as confirmed, probable, possible, ruled out, or not enough information. A total of 845 were classified with…

  8. Corrections to the density-functional theory electronic spectrum: Copper phthalocyanine

    DEFF Research Database (Denmark)

    Vazquez, Hector; Jelinek, P.; Brandbyge, Mads;

    2009-01-01

    A method for improving the electronic spectrum of standard Density-Functional Theory (DFT) calculations (i.e., LDA or GGA approximations) is presented, and its application is discussed for the case of the copper phthalocyanine (CuPc) molecule. The method is based on a treatment of exchange and co...

  9. Bound muon decay spectrum in the leading logarithmic accuracy

    CERN Document Server

    Szafron, Robert

    2016-01-01

    We compute the dominant, logarithmically enhanced radiative corrections to the electron spectrum in the bound muon decay in the whole experimentally interesting range. The corrected spectrum fits well the TWIST results. The remaining theoretical error, dominated by the nuclear charge distribution, can be reduced in the muon-electron conversion searches by measuring the spectrum slightly below the New Physics signal window.

  10. Measurements of the energy spectrum of electrons emanating from solid materials irradiated by a picosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Di Stefano, C. A., E-mail: carlosds@umich.edu; Kuranz, C. C.; Thomas, A. G. R.; Drake, R. P.; Keiter, P. A.; Rasmus, A. M.; Wan, W. C.; Joglekar, A. S.; McKelvey, A.; Zhao, Z.; Klein, S. R. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Seely, J. F. [Artep, Inc., Ellicott City, Mary land 21042 (United States); Williams, G. J.; Park, J.; Chen, H.; Kemp, G. E. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); MacDonald, M. J. [University of Michigan, Ann Arbor, Michigan 48109 (United States); SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Pereira, N. R. [Ecopulse, Inc., Springfield, Virginia 22150 (United States); Jarrott, L. C.; Peebles, J. [University of California, San Diego, Energy Research Center, La Jolla, California 92093 (United States); and others

    2015-04-15

    In this work, we present the results of experiments observing the properties of the electron stream generated laterally when a laser irradiates a metal. We find that the directionality of the electrons is dependent upon their energies, with the higher-energy tail of the spectrum (∼1 MeV and higher) being more narrowly focused. This behavior is likely due to the coupling of the electrons to the electric field of the laser. The experiments are performed by using the Titan laser to irradiate a metal wire, creating the electron stream of interest. These electrons propagate to nearby spectator wires of differing metals, causing them to fluoresce at their characteristic K-shell energies. This fluorescence is recorded by a crystal spectrometer. By varying the distances between the wires, we are able to probe the divergence of the electron stream, while by varying the medium through which the electrons propagate (and hence the energy-dependence of electron attenuation), we are able to probe the energy spectrum of the stream.

  11. On the PeV knee of cosmic rays spectrum and TeV cutoff of electron spectrum

    CERN Document Server

    Jin, Chao; Hu, Hong-Bo; Guo, Yi-Qing

    2016-01-01

    The origin of the cosmic-ray knee has remained a puzzle since its discovery over 60 years. In addition, Some latest experiments have revealed a spectral cutoff of the electron around 1 TeV. We find these two spectral breaks have a similar Lorentz factor $\\sim 10^6$, and interpret this similarity with a threshold interaction induced by a new particle X abundant in the Galaxy. The interaction process $CR \\ + \\ X \\ \\longrightarrow \\ CR \\ + \\ X^{\\prime}$ can take place when the effective energy is sufficient to convert it into the mass of another unknown particle $X^{\\prime}$ (as a representative to all possible threshold inelastic interactions), where the mass of $X^{\\prime}$ is $10^6$ higher than that of the X with respect to the above mentioned common Lorentz factor. Thus cosmic rays will lose their energy above the threshold and produce a spectral break. Under this scenario, we can reproduce the spectral break for both the nuclei and electron, and predict a flattened spectrum for electrons after the cutoff. G...

  12. A crystal detector for measuring beta and internal conversion electrons in flowing air containing fission gases

    Science.gov (United States)

    Schell, W. R.; Vives-Batlle, J.; Yoon, S. R.; Tobin, M. J.

    1999-02-01

    Low levels of radioactive gases are released from nuclear electric power generation, nuclear fuel reprocessing plants, nuclear weapons tests and from diagnostic medical uses of radioactive gas tracers. A prototype model of an inorganic scintillator - Crystal Gas Electron Detector (CGED) - was built for measurements of xenon isotopes in-line by detecting the beta and internal conversion (IC) electrons present in atmospheric samples. The detection and quantification of the radionuclide spectra are accomplished, during air flow, without complete purification of the fission gases. Initial operational tests and calibrations made permit the integration of the CGED into a portable Gas Analysis, Separation and Purification (GASP) system [1-3]. The CGED detector, Pulse Shaping and Timing (PSA) electronics, and mathematical treatment of the accumulated spectra are used to resolve the K and LMNO-IC electrons and beta continuum. These data are used, in-line, for dating the age of an air parcel containing fission gases released from nuclear reactors and/or from nuclear weapons tests, as part of the monitoring equipment required to enforce the Comprehensive Test Ban Treaty, CTBT. This report is one of a series of papers providing the design features, operational methods, calibration, and applications of radioactive gas analysis system to the International CTBT.

  13. The cosmic ray electron spectrum and its modulation from 1968 through 1972

    Science.gov (United States)

    Fulks, G.; Meyer, P.; Lheureux, J.

    1974-01-01

    Over the past five years we have measured the energy spectrum of primary cosmic ray electrons with both a balloon-borne and a satellite absorption spectrometer. All of the balloon flights used identical equipment that was launched each summer from Fort Churchill, Manitoba, Canada. The satellite, OGO-5, has been in an eccentric orbit since March 1968. Together these instruments provide the electron spectrum over a range of energy from 20 MeV to 20 GeV. This wide range and the substantial span of time covered by the measurements permit a detailed study of the solar modulation of electrons. These results are compared with the modulation of the nuclear components as observed by a neutron monitor and interpreted using the cosmic ray transport equation.

  14. Measurement of the solar neutrino energy spectrum using neutrino-electron scattering

    CERN Document Server

    Fukuda, Y; Ichihara, E; Inoue, K; Ishihara, K; Ishino, H; Itow, Y; Kajita, T; Kameda, J; Kasuga, S; Kobayashi, K; Kobayashi, Y; Koshio, Y; Miura, M; Nakahata, M; Nakayama, S; Okada, A; Okumura, K; Sakurai, N; Shiozawa, M; Suzuki, Y; Takeuchi, Y; Totsuka, Y; Yamada, S; Earl, M; Habig, A; Kearns, E; Messier, M D; Scholberg, K; Stone, J L; Sulak, L R; Walter, C W; Goldhaber, M; Barszczak, T; Casper, D; Gajewski, W; Halverson, P G; Hsu, J; Kropp, W R; Price, R L; Reines, F; Smy, M B; Sobel, H W; Vagins, M R; Ganezer, K S; Keig, W E; Ellsworth, R W; Tasaka, S; Flanagan, J W; Kibayashi, A; Learned, J G; Matsuno, S; Stenger, V J; Takemori, D; Ishii, T; Kanzaki, J; Kobayashi, T; Mine, S; Nakamura, K; Nishikawa, K; Oyama, Y; Sakai, A; Sakuda, M; Sasaki, O; Echigo, S; Kohama, M; Suzuki, A T; Haines, T J; Blaufuss, E; Kim, B K; Sanford, R; Svoboda, R; Chen, M L; Conner, Z; Goodman, J A; Sullivan, G W; Hill, J; Jung, C K; Martens, K; Mauger, C; McGrew, C; Sharkey, E; Viren, B; Yanagisawa, C; Doki, W; Miyano, K; Okazawa, H; Saji, C; Takahata, M; Nagashima, Y; Takita, M; Yamaguchi, T; Yoshida, M; Kim, S B; Etoh, M; Fujita, K; Hasegawa, A; Hasegawa, T; Hatakeyama, S; Iwamoto, T; Koga, M; Maruyama, T; Ogawa, H; Shirai, J; Suzuki, A; Tsushima, F; Koshiba, M; Nemoto, M; Nishijima, K; Futagami, T; Hayato, Y; Kanaya, Y; Kaneyuki, K; Watanabe, Y; Kielczewska, D; Doyle, R A; George, J S; Stachyra, A L; Wai, L L; Wilkes, R J; Young, K K

    1999-01-01

    A measurement of the energy spectrum of recoil electrons from solar neutrino scattering in the Super--Kamiokande detector is presented. The results shown here are obtained from 504 days of data taken between the 31st of May, 1996 and the 25th of March, 1998. The shape of the measured spectrum is compared with the expectation for solar B8 neutrinos. The comparison takes into account both kinematic and detector related effects in the measurement process. The spectral shape comparison between the observation and the expectation gives a chi-square of 25.3 with 15 degrees of freedom, corresponding to a 4.6% confidence level.

  15. Diffuse galactic continuum emission measured by COMPTEL and the cosmic-ray electron spectrum

    Science.gov (United States)

    Strong, A. W.; Diehl, R.; Schoenfelder, V.; Varendorff, M.; Youssefi, G.; Bloemen, H.; Hermsen, W.; De Vries, C.; Morris, D.; Stacy, J. G.

    1994-01-01

    Diffuse galactic continuum gamma-ray emission in the 0.75-30 MeV range from the inner Galaxy has been studied using data from COMPTEL on the Compton Gamma-Ray Observatory. Observations of the inner Galaxy from the Sky Survey have been used. The imaging properties of COMPTEL enable spatial analysis of the gamma-ray distribution using model fitting. A model based on atomic and molecular gas distributions in the Galaxy has been used to derive the emissivity spectrum of the gamma-ray emission and this spectrum is compared with theoretical estimates of bremsstrahlung emission from cosmic-ray electrons.

  16. Conversion electron spectroscopy at the FMA focal plane: Decay studies of proton-rich N {approximately} 82 nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Nisius, D.; Janssens, R.V.F.; Ahmad, I. [and others

    1995-08-01

    The FMA has proven to be an ideal instrument for the detailed study of the decay of microsecond isomers behind the focal plane following mass selection. In reactions leading to the population of nuclei with isomeric lifetimes longer than their flight time through the device, decay gamma rays and conversion electrons can be detected in an environment free from the backgrounds of prompt radiation and delta electrons. This was a very successful technique to study proton (h{sub 11/2}){sup n} seniority isomers in nuclei with Z > 64 and N {approximately} 82. Since isomeric decay gamma rays are emitted isotropically, conversion electrons are essential for the assignment of multipolarities in these nuclei. Furthermore, the low-energy transitions that depopulate isomeric states are typically highly converted and can escape gamma-ray detection, but they can be identified by their conversion electrons.

  17. Time-resolved electron spectrum diagnostics for a free-electron laser

    Science.gov (United States)

    Gillespie, W. A.; MacLeod, A. M.; Martin, P. F.; van der Meer, A. F. G.; van Amersfoort, P. W.

    1996-03-01

    Time-resolved electron-beam diagnostics have been developed for use with free-electron lasers (FELs) and associated electron sources, based on the techniques of secondary electron emission and optical transition radiation (OTR). The 32-channel OTR detector forms part of a high-resolution (0.18%) electron spectrometer with a time resolution of 50 ns. Variable-magnification optics allow the spectrometer to view single-macropulse spectra with widths in the range of 0.2%-7%; wider spectra are taken with several momentum settings. Design criteria for the spectrometer are presented, and experience of operating with the diagnostics over a range of FEL physics experiments is summarized. The spectrometer is used, in conjunction with optical diagnostics, in studies at FELIX of efficiency enhancement, pulse chirping, and stepped-undulator operation.

  18. First Calorimetric Measurement of OI-line in the Electron Capture Spectrum of $^{163}$Ho

    CERN Document Server

    Ranitzsch, P. C. -O.; Wegner, M.; Kempf, S.; Fleischmann, A.; Enss, C.; Gastaldo, L.; Herlert, A.; Johnston, K.

    2014-01-01

    The isotope $^{163}$Ho undergoes an electron capture process with a recommended value for the energy available to the decay, $Q_{\\rm EC}$, of about 2.5 keV. According to the present knowledge, this is the lowest $Q_{\\rm EC}$ value for electron capture processes. Because of that, $^{163}$Ho is the best candidate to perform experiments to investigate the value of the electron neutrino mass based on the analysis of the calorimetrically measured spectrum. We present for the first time the calorimetric measurement of the atomic de-excitation of the $^{163}$Dy daughter atom upon the capture of an electron from the 5s shell in $^{163}$Ho, OI-line. The measured peak energy is 48 eV. This measurement was performed using low temperature metallic magnetic calorimeters with the $^{163}$Ho ion implanted in the absorber. We demonstrate that the calorimetric spectrum of $^{163}$Ho can be measured with high precision and that the parameters describing the spectrum can be learned from the analysis of the data. Finally, we dis...

  19. Nanoscale triboelectric-effect-enabled energy conversion for sustainably powering portable electronics.

    Science.gov (United States)

    Wang, Sihong; Lin, Long; Wang, Zhong Lin

    2012-12-12

    Harvesting energy from our living environment is an effective approach for sustainable, maintenance-free, and green power source for wireless, portable, or implanted electronics. Mechanical energy scavenging based on triboelectric effect has been proven to be simple, cost-effective, and robust. However, its output is still insufficient for sustainably driving electronic devices/systems. Here, we demonstrated a rationally designed arch-shaped triboelectric nanogenerator (TENG) by utilizing the contact electrification between a polymer thin film and a metal thin foil. The working mechanism of the TENG was studied by finite element simulation. The output voltage, current density, and energy volume density reached 230 V, 15.5 μA/cm(2), and 128 mW/cm(3), respectively, and an energy conversion efficiency as high as 10-39% has been demonstrated. The TENG was systematically studied and demonstrated as a sustainable power source that can not only drive instantaneous operation of light-emitting diodes (LEDs) but also charge a lithium ion battery as a regulated power module for powering a wireless sensor system and a commercial cell phone, which is the first demonstration of the nanogenerator for driving personal mobile electronics, opening the chapter of impacting general people's life by nanogenerators.

  20. Dose-rate conversion factors for external exposure to photons and electrons

    Energy Technology Data Exchange (ETDEWEB)

    Kocher, D.C.

    1981-08-01

    Dose-rate conversion factors for external exposure to photons and electrons have been calculated for approximately 500 radionuclides of potential importance in environmental radiological assessments. The dose-rate factors were obtained using the DOSFACTER computer code. The results given in this report incorporate calculation of electron dose-rate factors for radiosensitive tissues of the skin, improved estimates of organ dose-rate factors for photons, based on organ doses for monoenergetic sources at the body surface of an exposed individual, and the spectra of scattered photons in air from monoenergetic sources in an infinite, uniformly contaminated atmospheric cloud, calculation of dose-rate factors for other radionuclides in addition to those of interest in the nuclear fuel cycle, and incorporation of updated radioactive decay data for all radionuclides. Dose-rate factors are calculated for three exposure modes - immersion in contaminated air, immersion in contaminated water, and exposure at a height of 1 m above a contaminated ground surface. The report presents the equations used to calculate the external dose-rate factors for photons and electrons, documentation of the revised DOSFACTER computer code, and a complete tabulation of the calculated dose-rate factors. 30 refs., 12 figs.

  1. Measurements of conversion electrons in the s-process branching point nucleus {sup 176}Lu

    Energy Technology Data Exchange (ETDEWEB)

    Battaglia, A.; Tan, W.; Avetisyan, R.; Casarella, C.; Gyurijinyan, A.; Manukyan, K.V.; Marley, S.T.; Nystrom, A.; Paul, N.; Siegl, K.; Smith, K.; Smith, M.K.; Strauss, S.Y.; Aprahamian, A. [University of Notre Dame, Department of Physics, Notre Dame, IN (United States)

    2016-05-15

    Conversion coefficients, gamma-gamma and gamma-electron coincidences were measured in the s-process branching point nucleus {sup 176}Lu. Our goal was to determine the multipolarities of the γ-ray transitions that connect the high and low K states of {sup 176}Lu. This {sup 176}Lu nucleus has a long-lived ground state (K=7{sup -}) of 37.6 Gy, a short-lived isomeric state (K=0{sup -}) at 122.8 keV with half-life of 3.6 h, as well as a 58 μs isomer at 1588 keV (K=14{sup +}). The excitation structure of this nucleus contains bands of intermediate spins of both positive and negative parities. The intermediate states can under certain stellar temperatures completely change the equilibrium between the isomer and ground state of {sup 176}Lu and change the abundance of this nucleus. We populated 37 previously known levels in this nucleus via the {sup 176}Yb(p,n) reaction and measured 42 conversion coefficients for γ-ray transitions including 17 of them for the first time. (orig.)

  2. The energy spectrum of cosmic-ray electrons measured with H.E.S.S.

    Energy Technology Data Exchange (ETDEWEB)

    Egberts, Kathrin

    2009-03-30

    The spectrum of cosmic-ray electrons has so far been measured using balloon and satellite-based instruments. At TeV energies, however, the sensitivity of such instruments is very limited due to the low flux of electrons at very high energies and small detection areas of balloon/satellite based experiments. The very large collection area of ground-based imaging atmospheric Cherenkov telescopes gives them a substantial advantage over balloon/ satellite based instruments when detecting very-high-energy electrons (> 300 GeV). By analysing data taken by the High Energy Stereoscopic System (H.E.S.S.), this work extends the known electron spectrum up to 4 TeV - a range that is not accessible to direct measurements. However, in contrast to direct measurements, imaging atmospheric Cherenkov telescopes such as H.E.S.S. detect air showers that cosmic-ray electrons initiate in the atmosphere rather than the primary particle. Thus, the main challenge is to differentiate between air showers initiated by electrons and those initiated by the hadronic background. A new analysis technique was developed that determines the background with the support of the machine-learning algorithm Random Forest. It is shown that this analysis technique can also be applied in other areas such as the analysis of diffuse {gamma} rays from the Galactic plane. (orig.)

  3. Electronic communication in tetrathiafulvalene (TTF)/C60 systems: toward molecular solar energy conversion materials?

    Science.gov (United States)

    Martín, Nazario; Sánchez, Luis; Herranz, María Angeles; Illescas, Beatriz; Guldi, Dirk M

    2007-10-01

    The covalent connection of the electron acceptor C 60 to p-quinonoid pi-extended tetrathiafulvalenes (exTTFs) has allowed for the preparation of new photo- and electroactive conjugates able to act as artificial photosynthetic systems and active molecular materials in organic photovoltaics. The gain of aromaticity undergone by the pi-extended TTF unit in the oxidation process results in highly stabilized radical ion pairs, namely, C 60 (*-)/exTTF (*+). Lifetimes for such charge-separated states, ranging from a few nanoseconds to hundreds of microseconds, have been achieved by rationally modifying the nature of the chemical spacers. These long-lived radical pairs are called to play an important role for the conversion of sunlight into chemical or electrical power.

  4. Using the Fermilab proton source for a muon to electron conversion experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ankenbrandt, C.; Bogert, D.; DeJongh, F.; Geer, S.; McGinnis, D.; Neuffer, D.; Popovic, M.; Prebys, E.; /Fermilab

    2006-11-01

    The Fermilab proton source is capable of providing 8 GeV protons for both the future long-baseline neutrino program (NuMI), and for a new program of low energy muon experiments. In particular, if the 8 GeV protons are rebunched and then slowly extracted into an external beamline, the resulting proton beam would be suitable for a muon-to-electron conversion experiment designed to improve on the existing sensitivity by three orders of magnitude. We describe a scheme for the required beam manipulations. The scheme uses the Accumulator for momentum stacking, and the Debuncher for bunching and slow extraction. This would permit simultaneous operation of the muon program with the future NuMI program, delivering 10{sup 20} protons per year at 8 GeV for the muon program at the cost of a modest ({approx}10%) reduction in the protons available to the neutrino program.

  5. One-dimensional ordinary-slow extraordinary-Bernstein mode conversion in the electron cyclotron range of frequencies

    Science.gov (United States)

    Guo, Xingyu; Gao, Zhe; Jia, Guozhang

    2017-08-01

    The ordinary-slow extraordinary-Bernstein (O-SX-B) mode conversion in the electron cyclotron range of frequencies (ECRF) is revisited in slab geometry. The analytical formula of the O-SX conversion efficiency by Mjølhus is upgraded to include the magnetic field gradient, and the analytical expression of the SX-B conversion efficiency by Ram and Schultz is generalized for the case of oblique injection. Therefore, the conversion efficiency and optimal parallel refractive index for the whole O-SX-B conversion are obtained analytically and a shift of optimal parallel refractive index due to SX-FX loss is found. Full wave calculations are also presented to be compared with the analytical results.

  6. Electron spin resonance absorption spectrum of trivalent gadolinium in the oxide YAIG

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, S.A. (Argonne National Lab., IL); Marshall, T.; Serway, R.A.

    1978-01-01

    The electron spin resonance absorption spectrum of trivalent gadolinium in single crystals of yttrium-aluminium garnet is re-investigated at X-band and Q-band wavelengths. Fine structure spectral parameters deduced from Q-band wavelength measurements are found to predict satisfactorily spectral observations at both wavelengths. A list of spectral parameters deduced from data taken at 77/sup 0/K is given.

  7. Plasmon spectrum of degenerated electron gas. T=0 Green function method. Detailed pedagogical derivation

    OpenAIRE

    Mishonov, Todor M.; Atanasova, Liliya A.; Ivanov, Peter A; Valchev, Tihomir I.; Arnaudov, Dimo L.

    2003-01-01

    Plasmon spectrum and polarization operator of 1, 2, and 3 dimensional electron gas are calculated by T=0 Green function technique. It is shown that this field theory method gives probably the simplest pedagogical derivation of the statistical problem for the response function. The explanation is complimentary to the standard courses on condensed matter and plasma physics of the level of IX volume of Landau-Lifshitz encyclopedia on theoretical physics.

  8. Measurement of the Inclusive Electron Spectrum in Charmless Semileptonic B Decays Near the Kinematic Endpoint

    CERN Document Server

    Aubert, Bernard; Gaillard, Jean-Marc; Hicheur, A; Karyotakis, Yu; Lees, J P; Robbe, P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kral, J F; Le Clerc, C; Levi, M E; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Romosan, A; Ronan, Michael T; Shelkov, V G; Telnov, A V; Wenzel, W A; Harrison, T J; Hawkes, C M; Knowles, D J; O'Neale, S W; Penny, R C; Watson, A T; Watson, N K; Deppermann, T; Goetzen, K; Koch, H; Lewandowski, B; Peters, K; Schmücker, H; Steinke, M; Barlow, N R; Bhimji, W; Boyd, J T; Chevalier, N; Clark, P J; Cottingham, W N; MacKay, C; Wilson, F F; Abe, K; Hearty, C; Mattison, T S; McKenna, J A; Thiessen, D; Jolly, S; McKemey, A K; Blinov, V E; Bukin, A D; Buzykaev, A R; Golubev, V B; Ivanchenko, V N; Korol, A A; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Yushkov, A N; Best, D; Chao, M; Kirkby, D; Lankford, A J; Mandelkern, M A; McMahon, S; Stoker, D P; Buchanan, C; Chun, S; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Prell, S; Rahatlou, S; Raven, G; Schwanke, U; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Hart, P A; Kuznetsova, N P; Levy, S L; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beringer, J; Eisner, A M; Grothe, M; Heusch, C A; Lockman, W S; Pulliam, T; Schalk, T L; Schmitz, R E; Schumm, B A; Seiden, A; Turri, M; Walkowiak, W; Williams, D C; Wilson, M G; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S M; Mancinelli, G; Meadows, B T; Sokoloff, M D; Barillari, T; Bloom, P; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Roy, J; Smith, J G; Van Hoek, W C; Zhang, L; Harton, J L; Hu, T; Krishnamurthy, M; Soffer, A; Toki, W H; Wilson, R J; Zhang, J; Altenburg, D; Brandt, T; Brose, J; Colberg, T; Dickopp, M; Dubitzky, R S; Hauke, A; Maly, E; Müller-Pfefferkorn, R; Otto, S; Schubert, Klaus R; Schwierz, R; Spaan, B; Wilden, L; Bernard, D; Bonneaud, G R; Brochard, F; Cohen-Tanugi, J; Ferrag, S; T'Jampens, S; Thiebaux, C; Vasileiadis, G; Verderi, M; Anjomshoaa, A; Bernet, R; Khan, A; Lavin, D; Muheim, F; Playfer, S; Swain, J E; Tinslay, J; Falbo, M; Borean, C; Bozzi, C; Piemontese, L; Sarti, A; Treadwell, E; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; De Sangro, R; Falciai, D; Finocchiaro, G; Patteri, P; Peruzzi, I M; Piccolo, M; Zallo, A; Bagnasco, S; Buzzo, A; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Pastore, F C; Patrignani, C; Robutti, E; Santroni, A; Tosi, S

    2002-01-01

    A preliminary result on the study of the inclusive electron spectrum in B -> X_u e nu decays above the kinematic limit for the dominant B -> X_c e nu transitions is presented. This study is performed at the PEP-II asymmetric B Factory, where B meson pairs are produced in the decay of the Upsilon(4S) resonance. For the electron momentum range of 2.3 - 2.6 GeV/c in the Upsilon(4S) rest frame, the partial branching ratio is measured to be Delta B(B -> X_u e nu)=(0.152+-0.014+-0.014) 10^{-3}.

  9. Contribution from individual nearby sources to the spectrum of high-energy cosmic-ray electrons

    Energy Technology Data Exchange (ETDEWEB)

    Sedrati, R., E-mail: rafik.sedrati@univ-annaba.org; Attallah, R.

    2014-04-01

    In the last few years, very important data on high-energy cosmic-ray electrons and positrons from high-precision space-born and ground-based experiments have attracted a great deal of interest. These particles represent a unique probe for studying local comic-ray accelerators because they lose energy very rapidly. These energy losses reduce the lifetime so drastically that high-energy cosmic-ray electrons can attain the Earth only from rather local astrophysical sources. This work aims at calculating, by means of Monte Carlo simulation, the contribution from some known nearby astrophysical sources to the cosmic-ray electron/positron spectra at high energy (≥10GeV). The background to the electron energy spectrum from distant sources is determined with the help of the GALPROP code. The obtained numerical results are compared with a set of experimental data.

  10. Nonlinear modeling of low-to-high-frequency noise up-conversion in microwave electron devices

    Science.gov (United States)

    Filicori, Fabio; Traverso, Pier A.; Florian, Corrado

    2003-05-01

    Measurement-based, circuit-oriented non-linear noise modeling of microwave electron devices is still an open field of research, since existing approaches are not always suitable for the accurate prediction of low-frequency noise up-conversion to RF, which represents an essential information for the non-linear circuit analyses performed in the CAD of low phase-noise oscillators. In this paper a technology-independent, empirical approach to the modeling of noise contributions at the ports of electron devices, operating under strongly non-linear conditions, is proposed. Details concerning the analytical formulation of the model, which is derived by considering randomly time-varying perturbations in the basic equations of an otherwise conventional charge-controlled non-linear model, are presented, along with a discussion about the measurement techniques devoted to its experimental characterization. An example of application of the proposed Charge-Controlled Non-linear Noise (CCNN) model is considered in the case of a HBT transistor. Techniques devoted to the implementation of the obtained model in the framework of commercial CAD tools for circuit analysis and design are provided as well.

  11. Visible Light Excitation Characteristics of Novel Infrared Up-conversion Materials

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The Fluorescence excitation spectrum, emission spectrum and infrared up-conversion luminescence excitation spectrum are measured. The results of spectrum measurement show that the electron trapping materials CaS: Eu, Sm are of visible light excitation. The mechanism of visible light excitation is analyzed.

  12. Migration to Intermediate XML for Electronic Data (MIXED: Repository of Durable File Format Conversions

    Directory of Open Access Journals (Sweden)

    René van Horik

    2011-10-01

    Full Text Available Data Archiving and Networked Services (DANS, the Dutch scientific data archive for the social sciences and humanities, is engaged in the Migration to Intermediate XML for Electronic Data (MIXED project to develop open source software that implements the smart migration strategy concerning the long-term archiving of file formats. Smart migration concerns the conversion upon ingest of specific kinds of data formats, such as spreadsheets and databases, to an intermediate XML formatted file. It is assumed that the long-term curation of the XML files is much less problematic than the migration of binary source files and that the intermediate XML file can be converted in an efficient way to file formats that are common in the future. The features of the intermediate XML files are stored in the so-called Standard Data Formats for Preservation (SDFP specification. This XML schema can be considered an umbrella as it contains existing formal descriptions of file formats developed by others. SDFP also contain schemata developed by DANS, for example, a schema for file-oriented databases. It can be used, for example, for the binary DataPerfect format, that was used on a large scale about twenty years ago, and for which no existing XML schema could be found. The software developed in the MIXED project has been set up as a generic framework, together with a number of plug-ins. It can be considered as a repository of durable file format conversions. This paper contains an overview of the results of the MIXED project.

  13. Parallel electron streaming in the high-latitude E region and its effect on the incoherent scatter spectrum

    Science.gov (United States)

    Bahcivan, H.; Cosgrove, R. B.; Tsunoda, R. T.

    2006-07-01

    This article investigates the combined electron heating and streaming effects of low-frequency parallel electric fields on the incoherent scatter measurements of the high-latitude E region. The electric fields distort the electron distribution function, inducing changes on the amplitude and frequency of the ion-acoustic line in the measured incoherent scatter spectrum. If one assumes Maxwellian electrons, the measurements of electron and ion temperatures and electron density are subject to significant percentage errors during geomagnetically active conditions.

  14. Search for an admixture of sterile neutrino in the electron spectrum from tritium $\\beta$-decay

    CERN Document Server

    Abdurashitov, D; Likhovid, N; Lokhov, A; Tkachev, I; Yants, V

    2014-01-01

    We propose an experiment intended for search for an admixture of sterile neutrino with mass m$_s$ in the range of 1-8 keV that may be detected as specific distortion of the electron energy spectrum during tritium decay. The distortion is spread over large part of the spectrum so to reveal it one can use a detector with relatively poor (near 10-15%) energy resolution. A classic proportional counter is a simple natural choice for a tritium $\\beta$-decay detector. The method we are proposing is original in two respects. First, the counter is produced as a whole from fully-fused quartz tube allowing to measure current pulse directly from anode while providing high stability for a long time. Second, a modern digital acquisition technique can be used in measurements at ultrahigh count rate - up to 10$^6$ Hz. As a result an energy spectrum of tritium electrons containing up to 10$^{12}$ counts may be collected in a month of live time measurements. Due to high statistics an upper limit down to 10$^{-3}$..10$^{-5}$ ca...

  15. Implications of the cosmic ray electron spectrum and anisotropy measured with Fermi-LAT

    Energy Technology Data Exchange (ETDEWEB)

    Di Bernardo, Giuseppe [Gothenburg Univ. (Sweden). Dept. of Physics; Evoli, Carmelo [SISSA, Trieste (Italy); Gaggero, Daniele; Grasso, Dario [Pisa Univ. (Italy). Dipt. die Fisica; INFN, Pisa (Italy); Maccione, Luca [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Mazziotta, Mario Nicola [Istituto Nazionale di Fisica Nucleare, Bari (Italy)

    2010-11-15

    The Fermi Large Area Telescope (LAT) collaboration recently released the updated results of the measurement of the cosmic ray electron (CRE) spectrum and published its first constraints on the CRE anisotropy. With respect to the previous Fermi-LAT results, the CRE spectrum measurement was extended down from 20 to 7 GeV, thus providing a better lever arm to discriminate theoretical models. Here we show that the new data strengthen the evidence for the presence of two distinct electron and positron spectral components. Furthermore, we show that under such hypothesis most relevant CRE and positron data sets are remarkably well reproduced. Consistent fits of cosmic-ray nuclei and antiproton data, which are crucial to validate the adopted propagation setup(s) and to fix the solar modulation potential, are obtained for the Kraichnan and plain-diffusion propagation setups, while the Kolmogorov one is disfavored. We then confirm that nearby pulsars are viable source candidates of the required e{sup {+-}} extra-component. In that case, we show that the predicted CRE anisotropy is compatible with Fermi-LAT constraints and that a positive detection should be at hand of that observatory. Models assuming that only nearby supernova remnants contribute to the high energy tail of the observed CRE spectrum are in contrast with anisotropy limits. (orig.)

  16. Conversion electron measurements of 195Au using ICEBall for Nuclear Structure and Astrophysics at the University of Notre Dame

    Science.gov (United States)

    Battaglia, Anthony; Tan, Wanpeng; Aprahamian, Ani; Bauder, William; Casarella, Clark; Gurdal, Gulhan; Long, Alexander; Nystrom, Andrew; Siegl, Kevin; Smith, Karl; Smith, Mallory

    2013-10-01

    The Internal Conversion Electron Ball Array (ICEBall) consists of six Si(Li) detectors and it was recently re-comissioned at the University of Notre Dame Nuclear Science Laboratory for spectroscopic studies of heavy nuclei. For the commissioning experiment, a 16 MeV bunched proton beam was used from the FN Tandem for a (p,2n) reaction to populate low spin states of 195Au. Both conversion electrons and gamma-rays were detected in coincidence between ICEBall and a single high-purity germanium detector. A total of 14 conversion coeffcients were measured. The results will be presented and compared to previous results. This work was supported by the National Science Foundation under contract number NSF PHY-1068192. M.P. Metlay, J.X. Saladin, I.Y. Lee, and O. Dietzsch, Nucl. Instrum. Meth. A, 336, 162 (1993).

  17. Measurement of vibrational spectrum of liquid using monochromated scanning transmission electron microscopy-electron energy loss spectroscopy.

    Science.gov (United States)

    Miyata, Tomohiro; Fukuyama, Mao; Hibara, Akihide; Okunishi, Eiji; Mukai, Masaki; Mizoguchi, Teruyasu

    2014-10-01

    Investigations on the dynamic behavior of molecules in liquids at high spatial resolution are greatly desired because localized regions, such as solid-liquid interfaces or sites of reacting molecules, have assumed increasing importance with respect to improving material performance. In application to liquids, electron energy loss spectroscopy (EELS) observed with transmission electron microscopy (TEM) is a promising analytical technique with the appropriate resolutions. In this study, we obtained EELS spectra from an ionic liquid, 1-ethyl-3-methylimidazolium bis (trifluoromethyl-sulfonyl) imide (C2mim-TFSI), chosen as the sampled liquid, using monochromated scanning TEM (STEM). The molecular vibrational spectrum and the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap of the liquid were investigated. The HOMO-LUMO gap measurement coincided with that obtained from the ultraviolet-visible spectrum. A shoulder in the spectrum observed ∼0.4 eV is believed to originate from the molecular vibration. From a separately performed infrared observation and first-principles calculations, we found that this shoulder coincided with the vibrational peak attributed to the C-H stretching vibration of the [C2mim(+)] cation. This study demonstrates that a vibrational peak for a liquid can be observed using monochromated STEM-EELS, and leads one to expect observations of chemical reactions or aids in the analysis of the dynamic behavior of molecules in liquid. © The Author 2014. 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.

  18. A New Cost-Effective Multi-Drive Solution based on a Two-Stage Direct Power Electronic Conversion Topology

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2002-01-01

    of a protection circuit involving twelve diodes with full voltage/current ratings used only during faulty situations, makes this topology not so attractive. Lately, two stage Direct Power Electronic Conversion (DPEC) topologies have been proposed, providing similar functionality as a matrix converter but allowing...

  19. Electronic screen media for persons with autism spectrum disorders: results of a survey.

    Science.gov (United States)

    Shane, Howard C; Albert, Patti Ducoff

    2008-09-01

    Social and anecdotal reports suggest a predilection for visual media among individuals on the autism spectrum, yet no formal investigation has explored the extent of that use. Using a distributed questionnaire design, parents and caregivers report on time allotted toward media, including observable behaviors and communicative responses. More time was spent engaged with electronic screen media (ESM) than any other leisure activity. Television and movie viewing was more popular than computer usage. Across media platforms, animated programs were more highly preferred. Prevalent verbal and physical imitation was reported to occur during and following exposure to ESM. Clinical implications to strategically incorporate ESM into learning approaches for children with autism spectrum disorders (ASD) are provided.

  20. The electronic spectrum of a quasiperiodic potential: From the Hofstadter butterfly to the Fibonacci chain

    Energy Technology Data Exchange (ETDEWEB)

    Naumis, Gerardo G. [Departamento de Fisica-Qumica, Instituto de Fisica, Universidad Nacional Autonoma de Mexico (UNAM), Apartado Postal 20-364, 01000 Mexico, D.F. (Mexico)], E-mail: naumis@fisica.unam.mx; Lopez-Rodriguez, F.J. [Departamento de Fisica-Qumica, Instituto de Fisica, Universidad Nacional Autonoma de Mexico (UNAM), Apartado Postal 20-364, 01000 Mexico, D.F. (Mexico)

    2008-05-01

    We show that an electronic tight-binding Hamiltonian, defined in a quasiperiodic chain with an on-site potential given by a Fibonacci sequence, can be obtained using a superposition of Harper potentials. Since the spectrum of the Harper equation as a function of the magnetic flux is a fractal set, known as the Hofstadter butterfly, we follow the transformation of the butterfly to a new one that contains the Fibonacci potential and related approximants. As a result, the equation in reciprocal space for the Fibonacci case has the form of a chain with long range interaction between Fourier components. Then, the structure of the resulting spectrum is analyzed by calculating the components in reciprocal space of the related potentials. As an application, the correlator of each potential and some localization properties are obtained.

  1. Electrochemical and conversion electron Moessbauer study of corrosion induced by acid rain

    Energy Technology Data Exchange (ETDEWEB)

    Vertes, C.; Lakatos-Varsanyi, M.; Vertes, A. (Dept. of Physical Chemistry and of Nuclear Chemistry, Eoetvoes Univ., Budapest (Hungary)); Meisel, W.; Guetlich, P. (Inst. of Inorganic Chemistry and Analytical Chemistry, Univ. Mainz (Germany))

    1993-04-01

    The passivation of low carbon steel was studied in aqueous solution of 0.5M Na[sub 2]SO[sub 4]+0.001M NaHSO[sub 3] (pH 3.5, 6.5 and 8.5) which can be considered as a model of acid rain. The used conversion electron Moessbauer spectroscopy (CEMS) with the complementary electrochemical investigations proved that the sulfite ions induce pitting corrosion at pH 3.5 and 6.5, while the measurements showed much weaker pitting at pH 8.5. The compositions and thicknesses of the passive films formed during the electrochemical treatments are determined from the CEM spectra. Only [gamma]-FeOOH was found on the surface of the samples at pH 6.5 and 8.5. Nevertheless, at pH 3.5 the sextet belonging to Fe[sub 3]C appears in the spectra, and also FeSO[sub 4].H[sub 2]O could be detected in low concentration. (orig.).

  2. Elucidating energy and electron transfer dynamics within molecular assemblies for solar energy conversion

    Science.gov (United States)

    Morseth, Zachary Aaron

    The use of sunlight to make chemical fuels (i.e. solar fuels) is an attractive approach in the quest to develop sustainable energy sources. Using nature as a guide, assemblies for artificial photosynthesis will need to perform multiple functions. They will need to be able to harvest light across a broad region of the solar spectrum, transport excited-state energy to charge-separation sites, and then transport and store redox equivalents for use in the catalytic reactions that produce chemical fuels. This multifunctional behavior will require the assimilation of multiple components into a single macromolecular system. A wide variety of different architectures including porphyrin arrays, peptides, dendrimers, and polymers have been explored, with each design posing unique challenges. Polymer assemblies are attractive due to their relative ease of production and facile synthetic modification. However, their disordered nature gives rise to stochastic dynamics not present in more ordered assemblies. The rational design of assemblies requires a detailed understanding of the energy and electron transfer events that follow light absorption, which can occur on timescales ranging from femtoseconds to hundreds of microseconds, necessitating the use of sophisticated techniques. We have used a combination of time-resolved absorption and emission spectroscopies with observation times that span nine orders of magnitude to follow the excited-state evolution within single-site and polymer-based molecular assemblies. We complement experimental observations with electronic structure calculations, molecular dynamics simulations, and kinetic modeling to develop a microscopic view of these dynamics. This thesis provides an overview of work on single-site molecular assemblies and polymers decorated with pendant chromophores, both in solution and on surfaces. This work was made possible through extensive collaboration with Dr. Kirk Schanze's and Dr. John Reynolds' research groups who

  3. 'Shake-off' account of effects from a Beta-decay at determination of internal conversion coefficients due to secondary electron radiation

    CERN Document Server

    Mitrokhovich, N F

    2002-01-01

    By means of selection coincidence of gamma-quantum with the secondary electrons (e sub o -electrons) and beta-particles (gamma beta e sub 0 -coincidences) and special geometry of measurements the formation of e sub o -electrons from electrons of 'shake-off' accompanying beta-decay is chosen and its output is determined. Influence of this additional source of e sub o -electrons formation on the accuracy of the internal conversion coefficient determination is estimated, when the output of e sub o -electrons from electrons of conversion is defined on the output of e sub o -electrons from beta-particles.

  4. Measurement of the electron antineutrino mass from the beta spectrum of gaseous tritium

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, D.A.

    1986-12-01

    A measurement has been made of the mass of the electron antineutrino using the beta spectrum from a source of gaseous molecular tritium, and an upper limit of 36 eV/c/sup 2/ has been set on this mass. This measurement is the first upper limit on neutrino mass that does not rely on assumptions about the atomic configuration after the beta decay, and it has significantly smaller systematic errors associated with it than do previous measurements. 130 refs., 83 figs., 8 tabs.

  5. Integration of [(Co(bpy)₃]²⁺ electron mediator with heterogeneous photocatalysts for CO₂ conversion.

    Science.gov (United States)

    Lin, Jinliang; Hou, Yidong; Zheng, Yun; Wang, Xinchen

    2014-09-01

    An efficient chemical system for electron generation and transfer is constructed by the integration of an electron mediator ([Co(bpy)3](2+); bpy=2,2'-bipyridine) with semiconductor photocatalysts. The introduction of [Co(bpy)3](2+) remarkably enhances the photocatalytic activity of pristine semiconductor photocatalysts for heterogeneous CO2 conversion; this is attributable to the acceleration of charge separation. Of particular interest is that the excellent photocatalytic activity of heterogeneous catalysts can be developed as a universal photocatalytic CO2 reduction system. The present findings clearly demonstrate that the integration of an electron mediator with semiconductors is a feasible process for the design and development of efficient photochemical systems for CO2 conversion.

  6. Structural conversion and intramolecular electron transfer in ferrocenylanthraquinones triggered by Keggin type of heteropoly acid serving as proton source

    Institute of Scientific and Technical Information of China (English)

    LIU Shuxia; LI Dehui; SU Zhongmin; WANG Enbo

    2004-01-01

    Intramolecular electron transfer triggered by proton and the mechanism of structural conversion in a ethynylene-bridged ferrocene-anthraquinone organic electron donor(D)-acceptor(A) g-conjugated system (1-FcAq) in the presence of a Keggin type heteropoly acid as proton source are discussed. Heteropoly acids can stabilize the protonated ethynylene-bridged ferrocene-anthraquinone conjugated complex, and the stable protonated complex has been isolated in air and characterized by elemental analyses, IR,1H NMR, and CV. Upon the inducement of proton, electron transfer from ferrocene moiety (Fc) to anthraquinone moiety (Aq) causes the rearrangement of the conjugated system to create a fulvene-cumulene structuere.

  7. Dimensionality effect on two-electron energy spectrum: A fractional-dimension-based formulation

    Energy Technology Data Exchange (ETDEWEB)

    Correa, R.; Gutiérrez, W.; Mikhailov, I. [Escuela de Física, Universidad Industrial de Santander, A.A. 678, Bucaramanga (Colombia); Fulla, M.R. [Escuela de Física, Universidad Nacional de Colombia, A.A. 3840, Medellín (Colombia); Marín, J.H., E-mail: jhmarin@unal.edu.co [Escuela de Física, Universidad Nacional de Colombia, A.A. 3840, Medellín (Colombia)

    2015-07-17

    We analyze the spectrum of two-electron quantum dot with anisotropic parabolic confinement by using the fractional-dimension formulation which allows us to reduce the two-particle problem to two equations for independent particles in an effective space with variable dimension, ranging between two and three for ellipsoidal-shaped quantum dots and between one and two for elliptical-shaped quantum disks. The dependencies of energy levels on the heterostructure sizes for quantum dots, disks and wires are presented. - Highlights: • We report the two-electron eigenenergies in a quantum dot with anisotropic parabolic confinement. • Our model is versatile enough to consider changes in the dimension space from 3 to 2 and 2 to 1. • The two-electron structure is calculated in integer and fractional dimensional spaces. • The two-electron energy structure is sensitive to the quantum dot size and morphology changes. • The electron–electron Coulomb interaction is strongly dependent on the space dimensionality.

  8. Selection of noise power ratio spectrum models for electronic measurement of the Boltzmann constant

    CERN Document Server

    Coakley, Kevin J

    2016-01-01

    In the electronic measurement of the Boltzmann constant based on Johnson noise thermometry, the ratio of the power spectral densities of thermal noise across a resistor and pseudo-random noise synthetically generated by a quantum-accurate voltage-noise source varies with frequency due to mismatch between transmission lines. We model this ratio spectrum as an even polynomial function of frequency. For any given frequency range, defined by the maximum frequency $f_{max}$, we select the optimal polynomial ratio spectrum model with a cross-validation method and estimate the conditional uncertainty of the constant term in the ratio spectrum model in a way that accounts for both random and systematic effects associated with imperfect knowledge of the model with a resampling method. We select $f_{max}$ by minimizing this conditional uncertainty. Since many values of $f_{max}$ yield conditional uncertainties close to the observed minimum value on a frequency grid, we quantify an additional component of uncertainty as...

  9. Nondestructive diagnostic for electron bunch length in accelerators using the wakefield radiation spectrum

    Directory of Open Access Journals (Sweden)

    S. V. Shchelkunov

    2005-06-01

    Full Text Available We report the development of a nondestructive technique to measure bunch rms length in the psec range and below, and eventually in the fsec range, by measuring the high-frequency spectrum of wakefield radiation which is caused by the passage of a relativistic electron bunch through a channel surrounded by a dielectric. We demonstrate numerically that the generated spectrum is determined by the rms bunch length, while the specific axial and longitudinal charge distribution is not important. Measurement of the millimeter-wave spectrum will determine the rms bunch length in the psec range. This has been done using a series of calibrated mesh filters and the charge bunches produced by the 50 MeV rf linac system at ATF (Accelerator Test Facility, Brookhaven. We have developed the analysis of the factors crucial for achieving good accuracy in this measurement, and find the experimental data are fully understood by the theory. We point out that this technique also may be used for measuring fsec bunch lengths, using a prepared planar wakefield microstructure.

  10. Implications of the Cosmic Ray Electron Spectrum and Anisotropy measured with Fermi-LAT

    CERN Document Server

    Di Bernardo, Giuseppe; Gaggero, Daniele; Grasso, Dario; Maccione, Luca; Mazziotta, Mario Nicola

    2010-01-01

    The Fermi Large Area Telescope (LAT) collaboration recently released the updated results of the measurement of the cosmic ray electron (CRE) spectrum and published its first constraints on the CRE anisotropy. With respect to the previous Fermi-LAT results, the CRE spectrum measurement was extended down from 20 to 7 GeV, thus providing a better lever arm to discriminate theoretical models. Here we show that the new data strengthen the evidence for the presence of two distinct electron and positron spectral components. Furthermore, we show that under such hypothesis most relevant CRE and positron data sets are remarkably well reproduced. Consistent fits of cosmic-ray nuclei and antiproton data, which are crucial to validate the adopted propagation setup(s) and to fix the solar modulation potential, are obtained for the Kraichnan and plain-diffusion propagation setups, while the Kolmogorov one is disfavored. We then confirm that nearby pulsars are viable source candidates of the required $e^\\pm$ extra-component....

  11. Progression along the Bipolar Spectrum: A Longitudinal Study of Predictors of Conversion from Bipolar Spectrum Conditions to Bipolar I and II Disorders

    Science.gov (United States)

    Alloy, Lauren B.; Urošević, Snežana; Abramson, Lyn Y.; Jager-Hyman, Shari; Nusslock, Robin; Whitehouse, Wayne G.; Hogan, Michael

    2011-01-01

    Little longitudinal research has examined progression to more severe bipolar disorders in individuals with “soft” bipolar spectrum conditions. We examine rates and predictors of progression to bipolar I and II diagnoses in a non-patient sample of college-age participants (n = 201) with high General Behavior Inventory scores and childhood or adolescent onset of “soft” bipolar spectrum disorders followed longitudinally for 4.5 years from the Longitudinal Investigation of Bipolar Spectrum (LIBS) project. Of 57 individuals with initial cyclothymia or bipolar disorder not otherwise specified (BiNOS) diagnoses, 42.1% progressed to a bipolar II diagnosis and 10.5% progressed to a bipolar I diagnosis. Of 144 individuals with initial bipolar II diagnoses, 17.4% progressed to a bipolar I diagnosis. Consistent with hypotheses derived from the clinical literature and the Behavioral Approach System (BAS) model of bipolar disorder, and controlling for relevant variables (length of follow-up, initial depressive and hypomanic symptoms, treatment-seeking, and family history), high BAS sensitivity (especially BAS Fun Seeking) predicted a greater likelihood of progression to bipolar II disorder, whereas early age of onset and high impulsivity predicted a greater likelihood of progression to bipolar I (high BAS sensitivity and Fun-Seeking also predicted progression to bipolar I when family history was not controlled). The interaction of high BAS and high Behavioral Inhibition System (BIS) sensitivities also predicted greater likelihood of progression to bipolar I. We discuss implications of the findings for the bipolar spectrum concept, the BAS model of bipolar disorder, and early intervention efforts. PMID:21668080

  12. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, P; Vaz, P [Technological and Nuclear Institute, Estrada Nacional No 10, 2686-953 Sacavem (Portugal); Zankl, M; Schlattl, H, E-mail: pedro.nogueira@helmholtz-muenchen.de [Helmholtz Zentrum Muenchen-German Research Center for Environmental Health, Research Unit Medical Radiation Physics and Diagnostics, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)

    2011-11-07

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  13. Implications of Voyager 1 observations beyond the heliopause for the local interstellar electron spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Bisschoff, D.; Potgieter, M. S., E-mail: 20056950@nwu.ac.za [Centre for Space Research, North-West University, 2520 Potchefstroom (South Africa)

    2014-10-20

    Cosmic-ray observations made by the Voyager 1 spacecraft outside the dominant modulating influence of the heliosphere finally allow the comparison of computed galactic spectra with experimental data at lower energies. These computed spectra, based on galactic propagation models, can now be compared with observations at low energies by Voyager 1 and at high energies by the PAMELA space detector at Earth. This improves understanding of basic propagation effects and also provides solar modulation studies with reliable input spectra from 1 MeV to 100 GeV. We set out to reproduce the Voyager 1 electron observations in the energy range of 6-60 MeV, as well as the PAMELA electron spectrum above 10 GeV, using the GALPROP code. By varying the source spectrum and galactic diffusion parameters, specifically the rigidity dependence of spatial diffusion, we find local interstellar spectra that agree with both power-law spectra observed by Voyager 1 beyond the heliopause. The local interstellar spectrum between ∼1 MeV and 100 GeV indicates that it is the combination of two power laws, with E {sup –(1.45} {sup ±} {sup 0.15)} below ∼100 MeV and E {sup –(3.15} {sup ±} {sup 0.05)} above ∼100 MeV. A gradual turn in the spectral shape matching the power laws is found, between 2.0 ± 0.5) GeV and (100 ± 10) MeV. According to our simplified modeling, this transition is caused primarily by galactic propagation effects. We find that the intensity beyond the heliopause at 10 MeV is (350 ± 50) electrons m{sup –2} s{sup –1} sr{sup –1} MeV{sup –1}, decreasing to (50 ± 5) electrons m{sup –2} s{sup –1} sr{sup –1} MeV{sup –1} at 100 MeV.

  14. Bremsstrahlung and K(alpha) fluorescence measurements for inferring conversion efficiencies into fast ignition relevant hot electrons

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C D; Patel, P K; Hey, D S; Mackinnon, A J; Key, M H; Akli, K U; Bartal, T; Beg, F N; Chawla, S; Chen, H; Freeman, R R; Higginson, D P; Link, A; Ma, T Y; MacPhee, A G; Stephens, R B; Van Woerkom, L D; Westover, B; Porkolab, M

    2009-07-24

    The Bremsstrahlung and K-shell emission from 1 mm x 1 mm x 1 mm planar targets irradiated by a short-pulse 3 x 10{sup 18}-8 x 10{sup 19} W/cm{sup 2} laser were measured. The Bremsstrahlung was measured using a filter stack spectrometer with spectral discrimination up to 500 keV. K-shell emission was measured using a single photon counting charge coupled device (CCD). From Monte Carlo modeling of the target emission, conversion efficiencies into 1-3 MeV electrons of 3-12%, representing 20-40% total conversion efficiencies were inferred for intensities up to 8 x 10{sup 19} W/cm{sup 2}. Comparisons to scaling laws using synthetic energy spectra generated from the intensity distribution of the focal spot imply slope temperatures less than the ponderomotive potential of the laser. Resistive transport effects may result in potentials of a few hundred kV in the first few tens of microns in the target. This would lead to higher total conversion efficiencies than inferred from Monte Carlo modeling but lower conversion efficiencies into 1-3 MeV electrons.

  15. Identification of a millisecond isomeric state in Cd81129 via the detection of internal conversion and Compton electrons

    Directory of Open Access Journals (Sweden)

    J. Taprogge

    2014-11-01

    Full Text Available The decay of an isomeric state in the neutron-rich nucleus 129Cd has been observed via the detection of internal conversion and Compton electrons providing first experimental information on excited states in this nucleus. The isomer was populated in the projectile fission of a 238U beam at the Radioactive Isotope Beam Factory at RIKEN. From the measured yields of γ-rays and internal conversion electrons, a multipolarity of E3 was tentatively assigned to the isomeric transition. A half-life of T1/2=3.6(2 ms was determined for the new state which was assigned a spin of (21/2+, based on a comparison to shell model calculations performed using state-of-the-art realistic effective interactions.

  16. Identification of a millisecond isomeric state in 129Cd81via the detection of internal conversion and Compton electrons

    Energy Technology Data Exchange (ETDEWEB)

    Taprogge, J.; Jungclaus, A.; Grawe, H.; Nishimura, S.; Xu, Z. Y.; Doornenbal, P.; Lorusso, G.; Nacher, E.; Simpson, G. S.; Soderstrom, P. A.; Sumikama, T.; Kondev, F. G.

    2014-11-10

    The decay of an isomeric state in the neutron-rich nucleus 129Cd has been observed via the detection of internal conversion and Compton electrons providing first experimental information on excited states in this nucleus. The isomer was populated in the projectile fission of a 238U beam at the Radioactive Isotope Beam Factory at RIKEN. From the measured yields of γ-rays and internal conversion electrons, a multipolarity of E 3 was tentatively assigned to the isomeric transition. A half-life of T1/2=3.6(2) msT1/2=3.6(2) ms was determined for the new state which was assigned a spin of (21/2+)(21/2+), based on a comparison to shell model calculations performed using state-of-the-art realistic effective interactions.

  17. Continuous Emission Spectrum Measurement for Electron Temperature Determination in Low-Temperature Collisional Plasmas%Continuous Emission Spectrum Measurement for Electron Temperature Determination in Low-Temperature Collisional Plasmas

    Institute of Scientific and Technical Information of China (English)

    刘秋艳; 李弘; 陈志鹏; 谢锦林; 刘万东

    2011-01-01

    Continuous emission spectrum measurement is applied for the inconvenient diagnos- tics of low-temperature collisional plasmas. According to the physical mechanism of continuous emission, a simplified model is presented to analyze the spectrum in low temperature plasma. The validity of this model is discussed in a wide range of discharge parameters, including electron tem- perature and ionization degree. Through the simplified model, the continuous emission spectrum in a collisional argon internal inductively coupled plasma is experimentally measured to determine the electron temperature distribution for different gas pressures and radio-frequency powers. The inverse Abel transform is also applied for a better spatially resoluted results. Meanwhile, the result of the continuous emission spectrum measurement is compared to that of the electrostatic double probes, which indicates the effectiveness of this method.

  18. Enhanced signal dispersion in saturation transfer difference experiments by conversion to a 1D-STD-homodecoupled spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Pastor, Manuel; Vega-Vazquez, Marino [Universidade de Santiago de Compostela, Laboratorio Integral de Dinamica e Estructura de Biomoleculas Jose R. Carracido, Unidade de Resonancia Magnetica, Edificio CACTUS, RIAIDT (Spain); Capua, Antonia De [Seconda Universita degli Studi di Napoli, Dipartimento di Scienze Ambientali (Italy); Canales, Angeles [Centro de Investigaciones Biologicas, CSIC, Departamento de Estructura y funcion de proteinas (Spain); Andre, Sabine; Gabius, Hans-Joachim [Ludwig-Maximilians-Universitaet, Institut fuer Physiologische Chemie, Tieraerztliche Fakultaet (Germany); Jimenez-Barbero, Jesus [Centro de Investigaciones Biologicas, CSIC, Departamento de Estructura y funcion de proteinas (Spain)], E-mail: JJbarbero@cib.csic.es

    2006-10-15

    The saturation transfer difference (STD) experiment is a rich source of information on topological aspects of ligand binding to a receptor. The epitope mapping is based on a magnetization transfer after signal saturation from the receptor to the ligand, where interproton distances permit this process. Signal overlap in the STD spectrum can cause difficulties to correctly assign and/or quantitate the measured enhancements. To address this issue we report here a modified version of the routine experiment and a processing scheme that provides a 1D-STD homodecoupled spectrum (i.e. an experiment in which all STD signals appear as singlets) with line widths similar to those in original STD spectrum. These refinements contribute to alleviate problems of signal overlap. The experiment is based on 2D-J-resolved spectroscopy, one of the fastest 2D experiments under conventional data sampling in the indirect dimension, and provides excellent sensitivity, a key factor for the difference experiments.

  19. Energy spectrum and specific heat of two-dimensional electron systems with spin-orbit interaction in a magnetic field parallel to the conducting layer

    Science.gov (United States)

    Shevchenko, O. S.; Kopeliovich, A. I.

    2016-03-01

    The energy spectrum of a quasi-two-dimensional electron gas in an in-plane magnetic field is studied using the perturbation theory and quasiclassical approach in the presence of the Rashba and Dresselhaus spin-orbit coupling. The existence of the intersection of energy sublevels in electron spectrum is demonstrated. The reciprocal mass tensor of electrons is analyzed. The heat capacity of the degenerate electron gas is examined, and its relations with the key features of the spectrum are shown.

  20. Peculiarities of electron energy spectrum in Coulomb field of super heavy nucleus

    CERN Document Server

    Gitman, D M; Ferreira, R; Levin, A D

    2015-01-01

    Just after the Dirac equation was established, a number of physicists tried to comment on and solve the spectral problem for the Dirac Hamiltonian with the Coulomb field of arbitrarily large charge $Z$, especially with $Z$ that is more than the critical value $Z_{\\mathrm{c}}=\\alpha^{-1}\\simeq137,04$, making sometimes contradictory conclusions and presenting doubtful solutions. It seems that there is no consesus on this problem up until now and especially on the way of using corresponding solutions of the Dirac equation in calculating physical processes. That is why in the present article, we turn once again to discussing peculiarities of electron energy spectrum in the Coulomb field of superheavy nucleus. In the beginning, we remind the reader of a long story with a wrong interpretation of the problem in the case of a point nucleus and its present correct solution. We then turn to the spectral problem in the case of a regularized Coulomb field. Under a specific regularization, we derive an exact spectrum equa...

  1. Astrophysical Uncertainties in the Cosmic Ray Electron and Positron Spectrum From Annihilating Dark Matter

    CERN Document Server

    Simet, Melanie

    2009-01-01

    In recent years, a number of experiments have been conducted with the goal of studying cosmic rays at GeV to TeV energies. This is a particularly interesting regime from the perspective of indirect dark matter detection. To draw reliable conclusions regarding dark matter from cosmic ray measurements, however, it is important to first understand the propagation of cosmic rays through the magnetic and radiation fields of the Milky Way. In this paper, we constrain the characteristics of the cosmic ray propagation model through comparison with observational inputs, including recent data from the CREAM experiment, and use these constraints to estimate the corresponding uncertainties in the spectrum of cosmic ray electrons and positrons from dark matter particles annihilating in the halo of the Milky Way.

  2. Personality disorder symptom severity predicts onset of mood episodes and conversion to bipolar I disorder in individuals with bipolar spectrum disorder.

    Science.gov (United States)

    Ng, Tommy H; Burke, Taylor A; Stange, Jonathan P; Walshaw, Patricia D; Weiss, Rachel B; Urosevic, Snezana; Abramson, Lyn Y; Alloy, Lauren B

    2017-04-01

    Although personality disorders (PDs) are highly comorbid with bipolar spectrum disorders (BSDs), little longitudinal research has been conducted to examine the prospective impact of PD symptoms on the course of BSDs. The aim of this study is to examine whether PD symptom severity predicts shorter time to onset of bipolar mood episodes and conversion to bipolar I disorder over time among individuals with less severe BSDs. Participants (n = 166) with bipolar II disorder, cyclothymia, or bipolar disorder not otherwise specified completed diagnostic interview assessments of PD symptoms and self-report measures of mood symptoms at baseline. They were followed prospectively with diagnostic interviews every 4 months for an average of 3.02 years. Cox proportional hazard regression analyses indicated that overall PD symptom severity significantly predicted shorter time to onset of hypomanic (hazard ratio [HR] = 1.42; p conversion to bipolar I disorder (HR = 2.51; p conversion to bipolar I disorder (HR = 2.77; p < .001), whereas cluster C severity (HR = 1.56; p < .001) predicted shorter time to onset of major depressive episodes. These results support predisposition models in suggesting that PD symptoms may act as a risk factor for a more severe course of BSDs. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  3. Electronic structure, vibrational spectrum and photochemistry of the Fe+H 2 system

    Science.gov (United States)

    Granucci, Giovanni; Persico, Maurizio

    1992-11-01

    We present an ab initio study of the electronic structure of the Fe+H 2 system, based on the CIPSI adn CASSCF methods. The main points addressed in this paper are the nature of the electronic states of FeH 2, its equilibrium geometry and the attribution of the observed vibrational bands. The latter two problems are the object of controversial interpretation of the experimental data: our conclusion is that the molecule is linear in the ground quintet state, and the symmetric stretching band cannot be detected in the IR spectrum. In order to clarify the photochemistry of the Fe+H 2 system, we have determined potential energy curves for the insertion of the iron atom in the HH bond, in the ground and several excited states originating from Fe 5D (3d 64s 2), 5F (3d 74s), 5P (3d 74s), 5D° (3d 64s4p), 5F° (3d 64s4p) and 5P° (3d 64s4p).

  4. Exploring the Bermuda triangle of homonuclear diatomic spectroscopy: The electronic spectrum and structure of Ge2

    Science.gov (United States)

    Hostutler, David A.; Li, Haiyang; Clouthier, Dennis J.; Wannous, Ghassan

    2002-03-01

    The optical spectrum of jet-cooled Ge2 has been observed for the first time. Laser-induced fluorescence (LIF) and wavelength resolved emission spectra were recorded using the pulsed discharge technique with a tetramethylgermane precursor. Analysis of the spectra yielded the vibrational constants ωe″=287.9(47), ωexe″=0.81(55), ωeye″=0.0037(18), ωe'=189.0(15), ωexe'=6.41(30), and Te'=20 610.8(16) cm-1. High-resolution rotationally resolved spectra of several bands of 74Ge2 show two strong P and R branches and two very weak Q branches. We have assigned the band system as a Hund's case (c) Ω'=1-Ω″=1 transition from the ground 3Σg- state to a 3Σu- excited state. The bond lengths derived from the rotational constants are r0″=2.3680(1) Å and re'=2.5244(18) Å, an ˜0.16 Å increase on electronic excitation. Arguments are presented for assigning the transition to a σg2πu2→σg2πuπg electron promotion, although the observed increase in the bond length is much less than predicted by previous ab initio calculations. The absence of the 0u+-0g+ component in the spectra has been attributed to an excited state predissociation.

  5. Understanding Power Electronics and Electrical Machines in Multidisciplinary Wind Energy Conversion System Courses

    Science.gov (United States)

    Duran, M. J.; Barrero, F.; Pozo-Ruz, A.; Guzman, F.; Fernandez, J.; Guzman, H.

    2013-01-01

    Wind energy conversion systems (WECS) nowadays offer an extremely wide range of topologies, including various different types of electrical generators and power converters. Wind energy is also an application of great interest to students and with a huge potential for engineering employment. Making WECS the main center of interest when teaching…

  6. Understanding Power Electronics and Electrical Machines in Multidisciplinary Wind Energy Conversion System Courses

    Science.gov (United States)

    Duran, M. J.; Barrero, F.; Pozo-Ruz, A.; Guzman, F.; Fernandez, J.; Guzman, H.

    2013-01-01

    Wind energy conversion systems (WECS) nowadays offer an extremely wide range of topologies, including various different types of electrical generators and power converters. Wind energy is also an application of great interest to students and with a huge potential for engineering employment. Making WECS the main center of interest when teaching…

  7. Probing the ATIC peak in the cosmic-ray electron spectrum with H.E.S.S.

    Science.gov (United States)

    Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Barres de Almeida, U.; Bazer-Bachi, A. R.; Becherini, Y.; Behera, B.; Bernlöhr, K.; Bochow, A.; Boisson, C.; Bolmont, J.; Borrel, V.; Brucker, J.; Brun, F.; Brun, P.; Bühler, R.; Bulik, T.; Büsching, I.; Boutelier, T.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Chounet, L.-M.; Clapson, A. C.; Coignet, G.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; O'C. Drury, L.; Dubois, F.; Dubus, G.; Dyks, J.; Dyrda, M.; Egberts, K.; Emmanoulopoulos, D.; Espigat, P.; Farnier, C.; Feinstein, F.; Fiasson, A.; Förster, A.; Fontaine, G.; Füßling, M.; Gabici, S.; Gallant, Y. A.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Goret, P.; Göring, D.; Hauser, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Holleran, M.; Hoppe, S.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jung, I.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Kendziorra, E.; Kerschhaggl, M.; Khangulyan, D.; Khélifi, B.; Keogh, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Lamanna, G.; Lenain, J.-P.; Lohse, T.; Marandon, V.; Martin, J. M.; Martineau-Huynh, O.; Marcowith, A.; Masbou, J.; Maurin, D.; McComb, T. J. L.; Medina, M. C.; Moderski, R.; Moulin, E.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; Olive, J.-F.; de Oña Wilhelmi, E.; Orford, K. J.; Ostrowski, M.; Panter, M.; Paz Arribas, M.; Pedaletti, G.; Pelletier, G.; Petrucci, P.-O.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raubenheimer, B. C.; Raue, M.; Rayner, S. M.; Reimer, O.; Renaud, M.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Ruppel, J.; Sahakian, V.; Santangelo, A.; Schlickeiser, R.; Schöck, F. M.; Schröder, R.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Shalchi, A.; Sikora, M.; Skilton, J. L.; Sol, H.; Spangler, D.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Superina, G.; Szostek, A.; Tam, P. H.; Tavernet, J.-P.; Terrier, R.; Tibolla, O.; Tluczykont, M.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Venter, L.; Vialle, J. P.; Vincent, P.; Vivier, M.; Völk, H. J.; Volpe, F.; Wagner, S. J.; Ward, M.; Zdziarski, A. A.; Zech, A.

    2009-12-01

    The measurement of an excess in the cosmic-ray electron spectrum between 300 and 800 GeV by the ATIC experiment has - together with the PAMELA detection of a rise in the positron fraction up to ≈100 GeV - motivated many interpretations in terms of dark matter scenarios; alternative explanations assume a nearby electron source like a pulsar or supernova remnant. Here we present a measurement of the cosmic-ray electron spectrum with H.E.S.S. starting at 340 GeV. While the overall electron flux measured by H.E.S.S. is consistent with the ATIC data within statistical and systematic errors, the H.E.S.S. data exclude a pronounced peak in the electron spectrum as suggested for interpretation by ATIC. The H.E.S.S. data follow a power-law spectrum with spectral index of 3.0±0.1(stat.)± 0.3(syst.), which steepens at about 1 TeV. Supported by CAPES Foundation, Ministry of Education of Brazil.

  8. Recent Progress in Piezoelectric Conversion and Energy Harvesting Using Nonlinear Electronic Interfaces and Issues in Small Scale Implementation

    Directory of Open Access Journals (Sweden)

    Daniel Guyomar

    2011-06-01

    Full Text Available This paper aims at providing an up-to-date review of nonlinear electronic interfaces for energy harvesting from mechanical vibrations using piezoelectric coupling. The basic principles and the direct application to energy harvesting of nonlinear treatment of the output voltage of the transducers for conversion enhancement will be recalled, and extensions of this approach presented. Latest advances in this field will be exposed, such as the use of intermediate energy tanks for decoupling or initial energy injection for conversion magnification. A comparative analysis of each of these techniques will be performed, highlighting the advantages and drawbacks of the methods, in terms of efficiency, performance under several excitation conditions, complexity of implementation and so on. Finally, a special focus of their implementation in the case of low voltage output transducers (as in the case of microsystems will be presented.

  9. Bound muon decay spectrum in the leading logarithmic accuracy

    Science.gov (United States)

    Szafron, Robert; Czarnecki, Andrzej

    2016-09-01

    We compute the dominant, logarithmically enhanced radiative corrections to the electron spectrum in bound muon decay in the whole experimentally interesting range. The corrected spectrum fits well with the results from the TWIST Collaboration. The remaining theoretical error, dominated by the nuclear charge distribution, can be reduced in the muon-electron conversion searches by measuring the spectrum slightly below the new physics signal window.

  10. Nature of Electronically Excited States of Organic Compounds and Processes of Nonradiative Conversion

    Science.gov (United States)

    Mayer, G. V.; Plotnikov, V. G.; Artyukhov, V. Ya.

    2016-08-01

    Models of quantum-chemical calculation of rate constants for internal processes and intersystem crossing in polyatomic molecules are considered. The influence of the nature of electronically excited states in organic compounds is investigated. It is shown that the explicit allowance for the nature of wave functions of electronic states for estimation of electronic matrix elements of nonadiabaticity operators and spin-orbit interaction allows photophysical processes in organic compounds to be considered in detail.

  11. Absorption spectrum, mass spectrometric properties, and electronic structure of 1,2-benzoquinone.

    Science.gov (United States)

    Albarran, Guadalupe; Boggess, William; Rassolov, Vitaly; Schuler, Robert H

    2010-07-22

    Absorption spectrophotometric and mass spectrometric properties of 1,2-benzoquinone, prepared in aqueous solution by the hexachloroiridate(IV) oxidation of catechol and isolated by HPLC, are reported. Its absorption spectrum has a broad moderately intense band in the near UV with an extinction coefficient of 1370 M(-1)cm(-1) at its 389 nm maximum. The oscillator strength of this band contrasts with those of the order-of-magnitude stronger approximately 250 nm bands of most 1,4-benzoquinones. Gaussian analysis of its absorption spectrum indicates that it also has modestly intense higher energy bands in the 250-320 nm region. In atmospheric pressure mass spectrometric studies 1,2-benzoquinone exhibits very strong positive and negative mass 109 signals that result from the addition of protons and hydride ions in APCI and ESI ion sources. It is suggested that the hydride adduct is formed as the result of the highly polar character of ortho-quinone. On energetic collision the hydride adduct loses an H atom to produce the 1,2-benzosemiquinone radical anion. The present studies also show that atmospheric pressure mass spectral patterns observed for catechol are dominated by signals of 1,2-benzoquinone resulting from oxidation of catechol in the ion sources. Computational studies of the electronic structures of 1,2-benzoquinone, its proton and hydride ion adducts, and 1,2-benzosemiquinone radical anion are reported. These computational studies show that the structures of the proton and hydride adducts are similar and indicate that the hydride adduct is the proton adduct of a doubly negatively charged 1,2-benzoquinone. The contrast between the properties of 1,2- and 1,4-benzoquinone provides the basis for considerations on the effects of conjugation in aromatic systems.

  12. Dose conversion coefficients for electron exposure of the human eye lens: calculations including a whole body phantom.

    Science.gov (United States)

    Behrens, R

    2013-07-01

    In this work, conversion coefficients from electron fluence to absorbed dose to the eye lens were calculated using Monte Carlo simulations based on a detailed stylised eye model and a very simple but whole body phantom. These data supersede and complement data published earlier based on the simulation of only a single stylised eye. The new data differ from the old ones by not more than 3, 4, 7 and 16 % for angles of radiation incidence of α=0°, 15°, 30° and 45°, respectively, due to the inclusion of the whole body phantom. The data presented in the present work also complement those of a recent report of the International Commission on Radiological Protection (ICRP) (ICRP Publication 116), where conversion coefficients from electron fluence to absorbed dose to the lens of the eye are shown for solely 0°, 180° and isotropic radiation incidence (but for a much broader range of energies). In this article, values are provided for angles of incidence of 0° up to 180° in steps of 15° and for rotational geometry; no systematic deviation was observed from the values given in ICRP Publication 116 for 0° (based on the application of a bare eye) and 180° (based on the application of a voxel whole body phantom). Data are given for monoenergetic electrons from 0.1 up to 10 MeV and for a broad parallel beam geometry in vacuum.

  13. A study of specific features of the electronic spectrum of quantum dots in CdSe semiconductor

    Science.gov (United States)

    Mikhailov, A. I.; Kabanov, V. F.; Gorbachev, I. A.; Glukhovskoi, E. G.

    2016-08-01

    Monolayers of CdSe/CdS/ZnS quantum dots (QDs) formed on the aqueous subphase and transferred to solid substrates by the Langmuir-Blodgett method have been studied. The samples obtained were examined by transmission electron microscopy, atomic-force microscopy, and scanning tunnel microscopy. The structure of the QD monolayer obtained on the substrate was analyzed. Specific features of the electronic spectrum of the quantum objects formed in the samples under study were determined.

  14. Efficient spin-to-charge conversion in the 2D electron liquid at the LAO/STO interface

    Science.gov (United States)

    Chauleau, J.-Y.; Boselli, M.; Gariglio, S.; Weil, R.; de Loubens, G.; Triscone, J.-M.; Viret, M.

    2016-10-01

    Spin-to-charge conversion using the inverse Rashba-Edelstein effect is measured in the 2D electron liquid existing at the interface between LaAlO3 and SrTiO3. The effect is found to be larger than in the highly Rashba split Bi/Ag interface which we attribute to an amplifying effect due to a long carrier's momentum lifetime. The explanation is supported by temperature measurements and the Rashba field is also shown to be anisotropic in the interface plane.

  15. An Electromagnetic Spectrum for Millennial Students: Teaching Light, Color, Energy, and Frequency Using the Electronic Devices of Our Time

    Science.gov (United States)

    Murphy, Maureen Kendrick

    2010-01-01

    In this article, a comparison of student learning outcomes is made in sophomore-level physical science classes using a "traditional" pedagogical approach versus a "modern" approach. Specifically, when students were taught the electromagnetic spectrum using diagrams and examples that incorporate technological advances and electronic devices of our…

  16. The enhancement of 21.2%-power conversion efficiency in polymer photovoltaic cells by using mixed Au nanoparticles with a wide absorption spectrum of 400 nm-1000 nm

    Institute of Scientific and Technical Information of China (English)

    郝敬昱; 徐颖; 张玉佩; 陈淑芬; 李兴鳌; 汪联辉; 黄维

    2015-01-01

    Au nanoparticles (NPs) mixed with a majority of bone-like, rod, and cube shapes and a minority of irregu-lar spheres, which can generate a wide absorption spectrum of 400 nm–1000 nm and three localized surface plas-mon resonance peaks, respectively, at 525, 575, and 775 nm, are introduced into the hole extraction layer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) to improve optical-to-electrical conversion performances in polymer photovoltaic cells. With the doping concentration of Au NPs optimized, the cell performance is significantly improved: the short-circuit current density and power conversion efficiency of the poly(3-hexylthiophene): [6,6]-phenyl-C60-butyric acid methyl ester cell are increased by 20.54%and 21.2%, reaching 11.15 mA·cm−2 and 4.23%. The variations of optical, electrical, and morphology with the incorporation of Au NPs in the cells are analyzed in detail, and our results demonstrate that the cell performance improvement can be attributed to a synergistic reaction, including:1) both the local-ized surface plasmon resonance-and scattering-induced absorption enhancement of the active layer, 2) Au doping-induced hole transport/extraction ability enhancement, and 3) large interface roughness-induced efficient exciton dissociation and hole collection.

  17. Everyday social and conversation applications of theory-of-mind understanding by children with autism-spectrum disorders or typical development.

    Science.gov (United States)

    Peterson, Candida C; Garnett, Michelle; Kelly, Adrian; Attwood, Tony

    2009-02-01

    Children with autism-spectrum disorders (ASD) often fail laboratory false-belief tests of theory of mind (ToM). Yet how this impacts on their everyday social behavior is less clear, partly owing to uncertainty over which specific everyday conversational and social skills require ToM understanding. A new caregiver-report scale of these everyday applications of ToM was developed and validated in two studies. Study 1 obtained parent ratings of 339 children (85 with autism; 230 with Asperger's; 24 typically-developing) on the new scale and results revealed (a) that the scale had good psychometric properties and (b) that children with ASD had significantly more everyday mindreading difficulties than typical developers. In Study 2, we directly tested links between laboratory ToM and everyday mindreading using teacher ratings on the new scale. The sample of 25 children included 15 with autism and 10 typical developers aged 5-12 years. Children in both groups who passed laboratory ToM tests had fewer everyday mindreading difficulties than those of the same diagnosis who failed. Yet, intriguingly, autistic ToM-passers still had more problems with everyday mindreading than younger typically-developing ToM-failers. The possible roles of family conversation and peer interaction, along with ToM, in everyday social functioning were considered.

  18. Spin-to-Orbital Angular Momentum Conversion and Spin-Polarization Filtering in Electron Beams

    CERN Document Server

    Karimi, Ebrahim; Grillo, Vincenzo; Santamato, Enrico; 10.1103/PhysRevLett.108.044801

    2012-01-01

    We propose the design of a space-variant Wien filter for electron beams that induces a spin half-turn and converts the corresponding spin angular momentum variation into orbital angular momentum of the beam itself by exploiting a geometrical phase arising in the spin manipulation. When applied to a spatially coherent input spin-polarized electron beam, such a device can generate an electron vortex beam, carrying orbital angular momentum. When applied to an unpolarized input beam, the proposed device, in combination with a suitable diffraction element, can act as a very effective spin-polarization filter. The same approach can also be applied to neutron or atom beams.

  19. Measurement of the Neutron Spectrum of a DD Electronic Neutron Generator

    Energy Technology Data Exchange (ETDEWEB)

    D. L. Chichester; J. T. Johnson; E. H. Seabury

    2010-08-01

    A Cuttler-Shalev (C-S) 3He proportional counter has been used to measure the energy spectrum of neutrons from a portable deuterium-deuterium electronic neutron generator. To improve the analysis of results from the C-S detector digital pulse shape analysis techniques have been used to eliminate neutron recoil artifacts in the recorded data. Data was collected using a 8-GHz, 10-bit waveform digitizer with its full scale corresponding to approximately 6-MeV neutrons. The measurements were made with the detector axis perpendicular to the direction of ions in the ENG in a plane 0.5-m to the side of the ENG, measuring neutrons emitted at an angle from 87.3? to 92.7? with respect to the path of ions in the ENG. The system demonstrated an energy resolution of approximately 0.040 MeV for the thermal peak and approximately 0.13 MeV at the DD neutron energy. In order to achieve the ultimate resolution capable with this type of detector it is clear that a higher-precision digitizer will be needed.

  20. Single-electron gap in the spectrum of twisted bilayer graphene

    Science.gov (United States)

    Rozhkov, A. V.; Sboychakov, A. O.; Rakhmanov, A. L.; Nori, Franco

    2017-01-01

    We investigate the gap in the single-electron spectrum of twisted bilayer graphene. In a perfect infinite lattice of a twisted bilayer, the gap varies exponentially in response to weak changes of the twist angle. Such a large sensitivity makes theoretical predictions of the gap nearly impossible, since experimentally the twist angle is always known with finite accuracy. To address this issue, we numerically study finite clusters of twisted bilayer graphene. For finite systems, changing the twist angle causes a gradual crossover between gapless and gapped regimes. The crossover occurs when the finite-size quantization energy becomes comparable to the matrix elements responsible for the generation of the gap. We further argue that disorder scattering can induce similar crossover, in which the mean-free path plays the same role as the system size for the finite clusters. It is demonstrated that to observe the gap experimentally, it is necessary to have a sample of suitable purity and to possess the ability to tune the twist angle accurately.

  1. Modelling the Multi-band Afterglow of GRB 091127: Evidence of a Hard Electron Energy Spectrum with an Injection Break

    CERN Document Server

    Zhang, Qiang; Zong, Hong-Shi

    2016-01-01

    The afterglow of GRBs is believed to originate from the synchrotron emission of shock-accelerated electrons produced by the interaction between the outflow and the external medium. The accelerated electrons are usually assumed to follow a power law energy distribution with an index of $p$. Observationally, although most GRB afterglows have a $p$ larger than 2, there are still a few GRBs suggestive of a hard ($p<2$) electron spectrum. GRB 091127, with well-sampled broad-band afterglow data, shows evidence of a hard electron spectrum and strong spectral evolution, with a spectral break moving from high to lower energies. The spectral break evolves very fast and cannot be explained by the cooling break in the standard afterglow model, unless evolving microphysical parameters are assumed. Besides, the multi-band afterglow light curves show an achromatic break at around 33 ks. Based on the model of a hard electron spectrum with an injection break, we interpret the observed spectral break as the synchrotron freq...

  2. Two-dimensional angular energy spectrum of electrons accelerated by the ultra-short relativistic laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Borovskiy, A. V. [Department of Computer Science and Cybernetics, Baikal State University of Economics and Law, 11 Lenin Street, Irkutsk 664003 (Russian Federation); Galkin, A. L. [Coherent and Nonlinear Optics Department, A.M. Prokhorov General Physics Institute of the RAS, 38 Vavilov Street, Moscow 119991 (Russian Federation); Department of Physics of MBF, Pirogov Russian National Research Medical University, 1 Ostrovitianov Street, Moscow 117997 (Russian Federation); Kalashnikov, M. P., E-mail: galkin@kapella.gpi.ru [Max-Born-Institute for Nonlinear Optics and Short-Time Spectroscopy, 2a Max-Born-Strasse, Berlin 12489 (Germany)

    2015-04-15

    The new method of calculating energy spectra of accelerated electrons, based on the parameterization by their initial coordinates, is proposed. The energy spectra of electrons accelerated by Gaussian ultra-short relativistic laser pulse at a selected angle to the axis of the optical system focusing the laser pulse in a low density gas are theoretically calculated. The two-peak structure of the electron energy spectrum is obtained. Discussed are the reasons for its appearance as well as an applicability of other models of the laser field.

  3. Energy Dependence of Near-relativistic Electron Spectrum at Geostationary Orbit during the SEP Events of 2005

    Indian Academy of Sciences (India)

    A. Chandrasekhar Reddy; Jatin Rathod; Girija Rajaram; Radharani Alyana; D. S. Misra; C. G. Patil; M. Y. S. Prasad; A. G. Ananth

    2008-03-01

    In view of the renewed interest in the study of energetic particles in the outer radiation belt of the earth, we feel it will be helpful in looking for the energy dependence of the electron energy spectrum at geostationary orbit. This may give us some insight into how we can safeguard geostationary satellites from functional anomalies of the deep dielectric charging type, which are caused by charge accumulation and subsequent discharge of relativistic electrons. In this study we examine whether there is any energy dependence in relativistic electron enhancements at geosynchronous altitudes during solar energetic proton events of 2005.

  4. P.U.R.E. (purposeful, unambiguous, respectful, and effective) Conversations and electronic fetal monitoring: gaining consensus and collaboration.

    Science.gov (United States)

    Veltman, Larry; Larison, Kristine

    2010-11-01

    A revised nomenclature regarding electronic fetal heart rate monitoring was accepted at a National Institute of Child Health and Human Development consensus conference in 2008. At the heart of patient safety are communication strategies that enhance teamwork and collaboration between health care professionals. Communications is a complex 2-way process that involves more than transfer of factual information. P.U.R.E. (purposeful, unambiguous, respectful, and effective) Conversations in Obstetrics is an acronym that helps facilitate this communication process in perinatal care. P.U.R.E. stands for purposeful, unambiguous, respectful, and effective. The P.U.R.E. Conversations approach involves refinement of the mental processes associated with delivering the message, delivery of the message with data, accuracy, and direct requests for action, attention to relationships and behaviors between the communicating parties, and real-time assessment of the effectiveness of the communication. When the new electronic monitoring nomenclature is combined with an effective communication tool, one could expect to see a reduction in communication failures that could lead to adverse perinatal outcomes.

  5. Water-soluble phosphine-protected Au9 clusters: Electronic structures and nuclearity conversion via phase transfer

    Science.gov (United States)

    Yao, Hiroshi; Tsubota, Shuhei

    2017-08-01

    In this article, isolation, exploration of electronic structures, and nuclearity conversion of water-soluble triphenylphosphine monosulfonate (TPPS)-protected nonagold (Au9) clusters are outlined. The Au9 clusters are obtained by the reduction of solutions containing TPPS and HAuCl4 and subsequent electrophoretic fractionation. Mass spectrometry and elemental analysis reveal the formation of [Au9(TPPS)8]5- nonagold cluster. UV-vis absorption and magnetic circular dichroism (MCD) spectra of aqueous [Au9(TPPS)8]5- are quite similar to those of [Au9(PPh3)8]3+ in organic solvent, so the solution-phase structures are likely similar for both systems. Simultaneous deconvolution analysis of absorption and MCD spectra demonstrates the presence of some weak electronic transitions that are essentially unresolved in the UV-vis absorption. Quantum chemical calculations for a model compound [Au9(pH3)8]3+ show that the possible (solution-phase) skeletal structure of the nonagold cluster has D2h core symmetry rather than C4-symmetrical centered crown conformation, which is known as the crystal form of the Au9 compound. Moreover, we find a new nuclearity conversion route from Au9 to Au8; that is, phase transfer of aqueous [Au9(TPPS)8]5- into chloroform using tetraoctylammonium bromide yields [Au8(TPPS)8]6- clusters in the absence of excess phosphine.

  6. A New Cost-Effective Multi-Drive Solution based on a Two-Stage Direct Power Electronic Conversion Topology

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede

    2002-01-01

    The matrix converter is a single stage AC/AC converter, which is able to provide sinusoidal PWM output voltages and input currents, inherent bi-directional power flow with no need of bulky DC-capacitors and large line inductors. However, the increased number of active switches (18) and the need o...... shared by many loads, making this topology more cost effective. The functionality of the proposed two-stage multi-drive direct power electronic conversion topology is validated by experiments on a realistic laboratory prototype.......The matrix converter is a single stage AC/AC converter, which is able to provide sinusoidal PWM output voltages and input currents, inherent bi-directional power flow with no need of bulky DC-capacitors and large line inductors. However, the increased number of active switches (18) and the need...... of a protection circuit involving twelve diodes with full voltage/current ratings used only during faulty situations, makes this topology not so attractive. Lately, two stage Direct Power Electronic Conversion (DPEC) topologies have been proposed, providing similar functionality as a matrix converter but allowing...

  7. Fast and accurate conversion of atomic models into electron density maps

    Directory of Open Access Journals (Sweden)

    Carlos O.S. Sorzano

    2015-03-01

    Full Text Available New image processing methodologies and algorithms have greatly contributed to the signi cant progress in three-dimensional electron microscopy (3DEM of biological complexes we have seen over the last decades. Naturally, the availability of accurate procedures for the objective testing of new algorithms is a crucial requirement for the further advancement of the eld. A good and accepted testing work ow involves the generation of realistic 3DEM-like maps of biological macromolecules from which some measure of ground truth can be derived, ideally because their 3D atomic structure is already known. In this work we propose a very accurate generation of maps using atomic form factors for electron scattering. We thoroughly review current approaches in the eld, quantitatively demonstrating the bene ts of the new methodology. Additionally, we study a concrete example of the use of this approach for hypothesis testing in 3D Electron Microscopy.

  8. Thermionic and Photo-excited Electron Emission for Energy Conversion Processes

    Directory of Open Access Journals (Sweden)

    Patrick T. McCarthy

    2014-12-01

    Full Text Available This article describes advances in thermionic and photoemission materials and applications dating back to the work on thermionic emission by Guthrie in 1873 and the photoelectric effect by Hertz in 1887. Thermionic emission has been employed for electron beam generation from Edison’s work with the light bulb to modern day technologies such as scanning and transmission electron microscopy. The photoelectric effect has been utilized in common devices such as cameras and photocopiers while photovoltaic cells continue to be widely successful and further researched. Limitations in device efficiency and materials have thus far restricted large-scale energy generation sources based on thermionic and photoemission. However, recent advances in the fabrication of nanoscale emitters suggest promising routes for improving both thermionic and photo-enhanced electron emission along with newly developed research concepts, e.g., photonically enhanced thermionic emission. However, the abundance of new emitter materials and reduced dimensions of some nanoscale emitters increases the complexity of electron emission theory and engender new questions related to the dimensionality of the emitter. This work presents derivations of basic two and three-dimensional thermionic and photoemission theory along with comparisons to experimentally acquired data. The resulting theory can be applied to many different material types regardless of composition, bulk and surface structure.

  9. The Content of Beginning Special Educators' Conversations with Their Electronic Mentors

    Science.gov (United States)

    Gentry, Roberta

    2016-01-01

    This exploratory study examined the frequency and content of text-based interactions between special education mentors (n = 22) and mentees (n = 50) within the Electronic Mentoring for Student Success Program (eMSS). Perceived outcomes of participants, based on an open ended survey question, were also analyzed. The Interstate Teacher Assessment…

  10. MOSSBAUER-SPECTROSCOPY OF YB-170 THROUGH INTERNAL-CONVERSION OF ELECTRONS

    NARCIS (Netherlands)

    SAWICKI, JA; NIESEN, L

    1993-01-01

    This paper describes the first observation of the Mossbauer scattering for the 84.3 keV gamma-ray transition in ytterbium Yb-170, made by detecting the low-energy electrons emitted after resonant absorption of gamma-rays. The measurements were performed in sideways scattering geometry using a 50 mCi

  11. Possible primary-electron-spectrum hardening at $\\sim 240$ GeV: Implications for AMS-02 observation and the physical origin of cosmic ray excesses

    CERN Document Server

    Feng, Lei; He, Hao-Ning; Dong, Tie-Kuang; Fan, Yi-Zhong; Chang, Jin

    2014-01-01

    The data collected by ATIC, CREAM and PAMELA all display remarkable cosmic-ray-nuclei spectrum hardening above the magnetic rigidity $\\sim$ 240 GV. One natural speculation is that the primary electron spectrum also gets hardened at $\\sim 240$ GeV, which can partly account for the electron/positron total spectrum excess discovered by ATIC, HESS and Fermi-LAT. The subsequent positron-to-electron ratio may get flattened or even decreased, depending on the degree of the primary electron spectrum hardening. Such modification is detectable for AMS-02, a mission dedicated to measure the high energy cosmic ray spectra with unprecedented accuracy. The spectrum hardening of both primary-electrons and nuclei at $\\sim 240$ GV, if confirmed by AMS-02 in the future, is likely attributed to a "nearby" supernova-remnant-like source with a lifetime $\\lesssim 10^{13}$ s. Possible dark matter origin of the positron excess revealed by PAMELA is also investigated.

  12. Investigation on the energy spectrums of electrons in atmospheric pressure argon plasma jets and their dependences on the applied voltage

    Science.gov (United States)

    Chen, Xinxian; Tan, Zhenyu; Liu, Yadi; Li, Xiaotong; Pan, Jie; Wang, Xiaolong

    2017-08-01

    This work presents a systematical investigation on the spatiotemporal evolution of the energy spectrum of electrons in atmospheric pressure argon plasma jets and its dependence on the applied voltage. The investigations are carried out by means of the numerical simulation based on a particle-in-cell Monte-Carlo collision model. The characteristics of the spatiotemporal evolution of the energy spectrum of electrons (ESE) in the discharge space have been presented, and especially the mechanisms of inducing these characteristics have also been revealed. The present work shows the following conclusions. In the evolution of ESE, there is a characteristic time under each applied voltage. Before the characteristic time, the peak value of ESE decreases, the peak position shifts toward high energy, and the distribution of ESE becomes wider and wider, but the reverse is true after the characteristic time. The formation of these characteristics can be mainly attributed to the transport of electrons toward a low electric field as well as a balance between the energy gained from the electric field including the effect of space charges and the energy loss due to inelastic collisions in the process of electron transport. The characteristic time decreases with the applied voltage. In addition, the average energy of electrons at the characteristic time can be increased by enhancing the applied voltage. The results presented in this work are of importance for regulating and controlling the energy of electrons in the plasma jets applied to plasma medicine.

  13. Development of methodology for assessment of absorbed dose and stopping power for low energy conversion electrons; Desenvolvimento de uma metodologia para estimativa da dose absorvida e do poder de freamento para eletrons de conversao de baixa energia

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Ivan Pedro Salati de

    1995-08-01

    The evaluation of absorbed dose in the case of external and internalcontamination due to radionuclides is sometimes hard, because of the difficulties in the assessment of the absorbed dose caused by electrons with energy less than 100 KeV in mucous membrane. In this work, a methodology for assessment of absorbed dose and stopping power in VYNS (co-polymer of polivinyl chloride - acetate) absorbers, for the 62.5 KeV and 84-88 KeV energy {sup 109} Cd conversion electrons, working with a 4 {pi} proportional pressurized detector, is presented. In order to assure the reproducibility of measurement conditions, one of the detector halves has been used to obtain a spectrum of a thin {sup 109} Cd source, without absorber. The other half of the detector was used in concomitance to obtain spectra with different thicknesses if absorber. The absorbed energy was obtained subtracting each spectrum with absorber from the spectrum without absorber, which were stored in a microcomputer connected to signal processing systems by ACE type interface. The VYNS weight and thickness were evaluated using common radionuclide metrology procedures. As VYNS has characteristics similar to a tissue equivalent material, the results obtained are consistent with dosimetric concepts and have a good agreement with those of the literature. (author)

  14. CESR Conversion Damping Ring Studies of Electron Cloud Instabilities (CESR-TA)

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, David L.; Palmer, Mark A.

    2011-08-02

    In the International Linear Collider, two linear accelerators will accelerate bunches of positrons and electrons to over a hundred billion electron volts and collide them in a central detector. In order to obtain useful collision rates, the bunches, each containing twenty billion particles, must be compressed to a cross section of a few nanometers by a few hundred nanometers. In order to prepare these ultra high density bunches, damping rings (DRs) are employed before the linear accelerators. The DRs take the high emittance bunches that are provided by the electron and positron sources and, through the process of radiation damping, squeeze them into ultra low emittance beams that are ready for the main linear accelerators. In the damping rings, a number of effects can prevent the successful preparation of the beams. In the electron ring, an effect known as the fast ion instability can lead to beam growth and, in the positron ring, the build-up of an electron cloud (EC), which interacts with the circulating bunches, can produce the same effect. EC build-up and the subsequent interaction of the cloud with the positron beam in the DR have been identified as major risks for the successful construction of a linear collider. The CESRTA research program at the Cornell Electron Storage Ring (CESR) was developed in order to study the build-up of the EC, the details of its impact on ultra low emittance beams, as well as methods to mitigate the impact of the cloud. In the DR, the EC forms when synchrotron photons radiated from the circulating beam strike the walls of the vacuum chamber, resulting in the emission of photoelectrons. These low energy electrons can be accelerated across the vacuum chamber by the electric field of the beam, and strike the walls, causing the emission of secondary electrons. The secondary electrons are subsequently accelerated into the walls yet again via the same mechanism. The result is that the EC can rapidly begin to fill the vacuum chamber. In

  15. Light-Induced Conversion of Chemical Permeability to Enhance Electron and Molecular Transfer in Nanoscale Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Balgley, Renata; de Ruiter, Graham; Evmenenko, Guennadi; Bendikov, Tatyana; Lahav, Michal; van der Boom, Milko E.

    2016-12-21

    In this paper, we demonstrate how photochemically enhancing the permeability of metal–organic assemblies results in a significant enhancement of the electrochemical activity of metal complexes located within the assembly. The molecular assemblies consist of different layers of redox-active metal complexes ([M(mbpy-py)3][PF6]2; M = Ru or Os) that are separated by redox-inactive spacers consisting of 1,4-bis[2-(4-pyridyl)ethenyl]benzene (BPEB) and PdCl2 of variable thicknesses (0–13.4 nm). UV-irradiation (λ = 254 nm) of our assemblies induces a photochemical reaction in the redox-inactive spacer increasing the permeability of the assembly. The observed increase was evident by trapping organic (nBu4NBF4) and inorganic (NiCl2) salts inside the assemblies, and by evaluating the electrochemical response of quinones absorbed inside the molecular assemblies before and after UV irradiation. The increase in permeability is reflected by higher currents and a change in the directionality of electron transfer, i.e., from mono- to bidirectional, between the redox-active metal complexes and the electrode surface. The supramolecular structure of the assemblies dominates the overall electron transfer properties and overrules possible electron transfer mediated by the extensive π-conjugation of its individual organic components.

  16. Roadmap on optical energy conversion

    Science.gov (United States)

    Boriskina, Svetlana V.; Green, Martin A.; Catchpole, Kylie; Yablonovitch, Eli; Beard, Matthew C.; Okada, Yoshitaka; Lany, Stephan; Gershon, Talia; Zakutayev, Andriy; Tahersima, Mohammad H.; Sorger, Volker J.; Naughton, Michael J.; Kempa, Krzysztof; Dagenais, Mario; Yao, Yuan; Xu, Lu; Sheng, Xing; Bronstein, Noah D.; Rogers, John A.; Alivisatos, A. Paul; Nuzzo, Ralph G.; Gordon, Jeffrey M.; Wu, Di M.; Wisser, Michael D.; Salleo, Alberto; Dionne, Jennifer; Bermel, Peter; Greffet, Jean-Jacques; Celanovic, Ivan; Soljacic, Marin; Manor, Assaf; Rotschild, Carmel; Raman, Aaswath; Zhu, Linxiao; Fan, Shanhui; Chen, Gang

    2016-07-01

    For decades, progress in the field of optical (including solar) energy conversion was dominated by advances in the conventional concentrating optics and materials design. In recent years, however, conceptual and technological breakthroughs in the fields of nanophotonics and plasmonics combined with a better understanding of the thermodynamics of the photon energy-conversion processes reshaped the landscape of energy-conversion schemes and devices. Nanostructured devices and materials that make use of size quantization effects to manipulate photon density of states offer a way to overcome the conventional light absorption limits. Novel optical spectrum splitting and photon-recycling schemes reduce the entropy production in the optical energy-conversion platforms and boost their efficiencies. Optical design concepts are rapidly expanding into the infrared energy band, offering new approaches to harvest waste heat, to reduce the thermal emission losses, and to achieve noncontact radiative cooling of solar cells as well as of optical and electronic circuitries. Light-matter interaction enabled by nanophotonics and plasmonics underlie the performance of the third- and fourth-generation energy-conversion devices, including up- and down-conversion of photon energy, near-field radiative energy transfer, and hot electron generation and harvesting. Finally, the increased market penetration of alternative solar energy-conversion technologies amplifies the role of cost-driven and environmental considerations. This roadmap on optical energy conversion provides a snapshot of the state of the art in optical energy conversion, remaining challenges, and most promising approaches to address these challenges. Leading experts authored 19 focused short sections of the roadmap where they share their vision on a specific aspect of this burgeoning research field. The roadmap opens up with a tutorial section, which introduces major concepts and terminology. It is our hope that the roadmap

  17. Roadmap on optical energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Boriskina, Svetlana V.; Green, Martin A.; Catchpole, Kylie; Yablonovitch, Eli; Beard, Matthew C.; Okada, Yoshitaka; Lany, Stephan; Gershon, Talia; Zakutayev, Andriy; Tahersima, Mohammad H.; Sorger, Volker J.; Naughton, Michael J.; Kempa, Krzysztof; Dagenais, Mario; Yao, Yuan; Xu, Lu; Sheng, Xing; Bronstein, Noah D.; Rogers, John A.; Alivisatos, A. Paul; Nuzzo, Ralph G.; Gordon, Jeffrey M.; Wu, Di M.; Wisser, Michael D.; Salleo, Alberto; Dionne, Jennifer; Bermel, Peter; Greffet, Jean-Jacques; Celanovic, Ivan; Soljacic, Marin; Manor, Assaf; Rotschild, Carmel; Raman, Aaswath; Zhu, Linxiao; Fan, Shanhui; Chen, Gang

    2016-06-24

    For decades, progress in the field of optical (including solar) energy conversion was dominated by advances in the conventional concentrating optics and materials design. In recent years, however, conceptual and technological breakthroughs in the fields of nanophotonics and plasmonics combined with a better understanding of the thermodynamics of the photon energy-conversion processes reshaped the landscape of energy-conversion schemes and devices. Nanostructured devices and materials that make use of size quantization effects to manipulate photon density of states offer a way to overcome the conventional light absorption limits. Novel optical spectrum splitting and photon-recycling schemes reduce the entropy production in the optical energy-conversion platforms and boost their efficiencies. Optical design concepts are rapidly expanding into the infrared energy band, offering new approaches to harvest waste heat, to reduce the thermal emission losses, and to achieve noncontact radiative cooling of solar cells as well as of optical and electronic circuitries. Light-matter interaction enabled by nanophotonics and plasmonics underlie the performance of the third- and fourth-generation energy-conversion devices, including up- and down-conversion of photon energy, near-field radiative energy transfer, and hot electron generation and harvesting. Finally, the increased market penetration of alternative solar energy-conversion technologies amplifies the role of cost-driven and environmental considerations. This roadmap on optical energy conversion provides a snapshot of the state of the art in optical energy conversion, remaining challenges, and most promising approaches to address these challenges. Leading experts authored 19 focused short sections of the roadmap where they share their vision on a specific aspect of this burgeoning research field. The roadmap opens up with a tutorial section, which introduces major concepts and terminology. It is our hope that the roadmap

  18. Study of spectrum-splitting solar photovoltaic system

    Science.gov (United States)

    Zhao, Yuan; Sheng, Ming-Yu; Zhou, Wei-Xi; Shen, Yan; Hu, E. T.; Chen, J. B.; Xu, Ming; Zheng, Yu-Xiang; Lee, Young-Pak; Lynch, David W.; Chen, Liang-Yao

    2011-05-01

    The photoelectrical responsibility of single photo-electronic devices makes it difficult to achieve high efficiency of photoelectric conversion in the full solar spectrum range. The key to overcome the physical limits is to develop the system consisting of a set of solar cells in which the photo-electronic conversion of each cell will match to the sub-spectrum of the solar radiation with high conversion efficiency. In this work, we have used the spectrum splitting method to divide the solar spectrum into four sub-ranges of 400-630nm, 630-800nm, 800-900nm and 900-1800nm, respectively. Four high performance single-junction photo diodes are used, and each of them has high quantum-efficiency of photo-electronic conversion matching to the sub-ranges of solar spectrum. Under the 0.5-6.0 SUN radiation condition, the photo-electrical conversion efficiency of the system with four solar cells has been measured with the result to show that the photo-electric conversion efficiency of 35% is achieved under the typical 2.8 SUN radiation condition. The results given in this work will provide a way to show the potencial to realize a high photo-electric conversion efficiency (>40%) of the solar system in application.

  19. Measurement of the Electron Energy Spectrum and its Moments in Inclusive B->X e nu Decays

    CERN Document Server

    Aubert, B; Boutigny, D; Couderc, F; Gaillard, J M; Hicheur, A; Karyotakis, Yu; Lees, J P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Le Clerc, C; Levi, M E; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, Michael T; Shelkov, V G; Telnov, A V; Wenzel, W A; Ford, K; Harrison, T J; Hawkes, C M; Morgan, S E; Watson, A T; Watson, N K; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Wilson, F F; Abe, K; Çuhadar-Dönszelmann, T; Hearty, C; Mattison, T S; McKenna, J A; Thiessen, D; Kyberd, P; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Eschrich, I; Kirkby, D; Lankford, A J; Mandelkern, M A; Mommsen, R K; Röthel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Gary, J W; Shen, B C; Wang, K; Del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Levy, S L; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Eisner, A M; Heusch, C A; Lockman, W S; Schalk, T; Schmitz, R E; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S M; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Clark, P J; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Smith, J G; Van Hoek, W C; Zhang, L; Harton, J L; Hu, T; Soffer, A; Toki, W H; Wilson, R J; Altenburg, D; Brandt, T; Brose, J; Colberg, T; Dickopp, M; Feltresi, E; Hauke, A; Lacker, H M; Maly, E; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Schubert, J; Schubert, Klaus R; Schwierz, R; Spaan, B; Bernard, D; Bonneaud, G R; Brochard, F; Grenier, P; Thiebaux, C; Vasileiadis, G; Verderi, M; Bard, D J; Khan, A; Lavin, D; Muheim, F; Playfer, S; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Sarti, A; Treadwell, E; Baldini-Ferroli, R; Calcaterra, A; De Sangro, R; Finocchiaro, G; Patteri, P; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Brandenburg, G; Morii, M; Won, E; Dubitzky, R S; Langenegger, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Gaillard, J R; Morton, G W; Nash, J A; Taylor, G P; Grenier, G J; Lee, S J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Yi, J; Davier, M; Grosdidier, G; Höcker, A; Laplace, S; Le Diberder, F R; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Coleman, J P; Fry, J R; Gabathuler, Erwin; Gamet, R; Kay, M; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Harrison, P F; Mohanty, G B; Brown, C L; Cowan, G; Flack, R L; Flächer, H U; George, S; Green, M G; Kurup, A; Marker, C E; McMahon, T R; Ricciardi, S; Salvatore, F; Vaitsas, G; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hart, P A; Hodgkinson, M C; Lafferty, G D; Lyon, A J; Williams, J C; Farbin, A; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Stängle, H; Willocq, S; Cowan, R; Sciolla, G; Taylor, F; Yamamoto, R K; Mangeol, D J J; Patel, P M; Robertson, S H; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L M; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Taras, P; Nicholson, H; Cartaro, C; Cavallo, N; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M; Raven, G; Wilden, L; Jessop, C P; LoSecco, J M; Gabriel, T A; Allmendinger, T; Brau, B; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Ter-Antonian, R; Wong, Q K; Brau, J E; Frey, R; Igonkina, O; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Tiozzo, G; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; La Vaissière, C de; Del Buono, L; Hamon, O; John, M J J; Leruste, P; Ocariz, J; Pivk, M; Roos, L; T'Jampens, S; Therin, G; Manfredi, P F; Re, V; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Anulli, F; Biasini, M; Peruzzi, I M; Pioppi, M; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bucci, F; Calderini, G; Carpinelli, M; Del Gamba, V; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Martínez-Vidal, F; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Sandrelli, F; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Danielson, N; Elmer, P; Lü, C; Miftakov, V; Olsen, J; Smith, A J S; Varnes, E W; Bellini, F; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Li Gioi, L; Mazzoni, M A; Morganti, S; Pierini, M; Piredda, G; Safai-Tehrani, F; Voena, C; Christ, S; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B J; Geddes, N I; Gopal, G P; Olaiya, E O; Xella, S M; Aleksan, Roy; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P F; Hamel de Monchenault, G; Kozanecki, Witold; Langer, M; Legendre, M; London, G W; Mayer, B; Schott, G; Vasseur, G; Yéche, C; Zito, M; Purohit, M V; Weidemann, A W; Yumiceva, F X; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmüller, O L; Convery, M R; Cristinziani, M; De Nardo, Gallieno; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W M; Elsen, E E; Field, R C; Glanzman, T; Gowdy, S J; Hadig, T; Halyo, V; Hrynóva, T; Innes, W R; Kelsey, M H; Kim, P; Kocian, M L; Leith, D W G S; Libby, J; Luitz, S; Lüth, V; Lynch, H L; Marsiske, H; Messner, R; Müller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Petrak, S; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Simi, G; Snyder, A; Soha, A; Stelzer, J; Su, D; Sullivan, M K; Vavra, J; Wagner, S R; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wittgen, M; Wright, D H; Young, C C; Burchat, Patricia R; Edwards, A J; Meyer, T I; Petersen, B A; Roat, C; Ahmed, S; Alam, M S; Ernst, J A; Saeed, M A; Saleem, M; Wappler, F R; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Kim, H; Ritchie, J L; Satpathy, A; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bóna, M; Gallo, F; Gamba, D; Borean, C; Bosisio, L; Cossutti, F; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Vuagnin, G; Panvini, R S; Banerjee, Sw; Brown, C M; Fortin, D; Jackson, P D; Kowalewski, R V; Roney, J M; Band, H R; Dasu, S; Datta, M; Eichenbaum, A M; Hollar, J J; Johnson, J R; Kutter, P E; Li, H; Liu, R; Di Lodovico, F; Mihályi, A; Mohapatra, A K; Pan, Y; Prepost, R; Sekula, S J; Tan, P; Von Wimmersperg-Töller, J H; Wu, J; Wu, S L; Yu, Z; Neal, H

    2004-01-01

    We report a measurement of the inclusive electron energy spectrum for semileptonic decays of B mesons in a data sample of 52 million Y4S -> BBar decays collected with the BABAR detector at the PEP-II asymmetric-energy B-meson factory at SLAC. We determine the branching fraction, first, second, and third moments of the spectrum for lower cut-offs on the electron energy between 0.6 and 1.5 GeV. We measure the partial branching fraction to be Br(B -> X e nu, E_e>0.6 GeV) = (10.36 +-0.06(stat.) +-0.23(sys))%.

  20. Photodissociation of carbon dioxide in singlet valence electronic states. II. Five state absorption spectrum and vibronic assignment

    CERN Document Server

    Grebenshchikov, Sergy Yu

    2013-01-01

    The absorption spectrum of CO$_2$ in the wavelength range 120\\,nm --- 160\\,nm is analyzed by means of quantum mechanical calculations performed using vibronically coupled PESs of five singlet valence electronic states and the coordinate dependent transition dipole moment vectors. The thermally averaged spectrum, calculated for T=190\\,K via Boltzmann averaging of optical transitions from many initial rotational states, accurtely reproduces the experimental spectral envelope, consisting of a low and a high energy band, the positions of the absorption maxima, their FWHMs, peak intensities, and frequencies of diffuse structures in each band. Contributions of the vibronic interactions due to Renner-Teller coupling, conical intersections, and the Herzberg-Teller effect are isolated and the calculated bands are assigned in terms of adiabatic electronic states. Finally, diffuse structures in the calculated bands are vibronically assigned using wave functions of the underlying resonance states. It is demonstrated that...

  1. A hot-electron thermophotonic solar cell demonstrated by thermal up-conversion of sub-bandgap photons.

    Science.gov (United States)

    Farrell, Daniel J; Sodabanlu, Hassanet; Wang, Yunpeng; Sugiyama, Masakazu; Okada, Yoshitaka

    2015-11-06

    The direct conversion of solar energy to electricity can be broadly separated into two main categories: photovoltaics and thermal photovoltaics, where the former utilizes gradients in electrical potential and the latter thermal gradients. Conventional thermal photovoltaics has a high theoretical efficiency limit (84%) but in practice cannot be easily miniaturized and is limited by the engineering challenges of sustaining large (>1,000 K) temperature gradients. Here we show a hot-carrier-based thermophotonic solar cell, which combines the compact nature of photovoltaic devices with the potential to reach the high-efficiency regime of thermal photovoltaics. In the device, a thermal gradient of 500 K is established by hot electrons, under Stokes illumination, rather than by raising the temperature of the material itself. Under anti-Stokes (sub-bandgap) illumination we observe a thermal gradient of ∼20 K, which is maintained by steady-state Auger heating of carriers and corresponds to a internal thermal up-conversion efficiency of 30% between the collector and solar cell.

  2. Enhancement of Electron Transfer in Various Photo-Assisted Oxidation Processes for Nitro-Phenolic Compound Conversion

    Science.gov (United States)

    Khue, Do Ngoc; Lam, Tran Dai; Minh, Do Binh; Loi, Vu Duc; Nam, Nguyen Hoai; Bach, Vu Quang; Van Anh, Nguyen; Van Hoang, Nguyen; Hu'ng, Dao Duy

    2016-08-01

    The present study focuses on photo-assisted advanced oxidation processes (AOPs) with strongly enhanced electron transfer for degradation of nitro-phenolic compounds in aqueous medium. The effectiveness of these processes was estimated based on the pseudo-first order rate constant k determined from high-performance liquid chromatography. The degradation of four different nitro-phenolic compounds was systematically studied using selected AOPs; these four compounds were nitrophenol, dinitrophenol, trinitrophenol and trinitroresorcin. It was observed that the combination of ultraviolet light with hydrogen peroxide H2O2 enhanced and maintained hydroxyl radicals, and therefore increased the conversion yield of organic pollutants. These AOPs provided efficient and green removal of stable organic toxins found in a wide range of industrial wastewater.

  3. A simple setup to measure muon lifetime and electron energy spectrum of muon decay and its Monte Carlo simulation

    CERN Document Server

    Hu, Yushi; Mei, Yefeng; Zhang, Zhao; Ning, Chuangang

    2016-01-01

    We designed a simple setup to measure the muon lifetime and the electron energy spectra of muon decay. A low cost coincidental circuit was designed to select the signals of muon decay events detected by a plastic scintillator detector. It triggered a digital oscilloscope to record the signals of muon decay events for measuring the muon lifetime and electron energy spectrum. A Landau-distribution energy loss method was introduced to conduct the energy calibration of the system. The experimental results were well reproduced by the Monte Carlo simulation. The software and hardware of the system are completely open to students, thus more helpful for instruction and motivation.

  4. A direct current rectification scheme for microwave space power conversion using traveling wave electron acceleration

    Science.gov (United States)

    Manning, Robert M.

    1993-01-01

    The formation of the Vision-21 conference held three years ago allowed the present author to reflect and speculate on the problem of converting electromagnetic energy to a direct current by essentially reversing the process used in traveling wave tubes that converts energy in the form of a direct current to electromagnetic energy. The idea was to use the electric field of the electromagnetic wave to produce electrons through the field emission process and accelerate these electrons by the same field to produce an electric current across a large potential difference. The acceleration process was that of cyclotron auto-resonance. Since that time, this rather speculative ideas has been developed into a method that shows great promise and for which a patent is pending and a prototype design will be demonstrated in a potential laser power beaming application. From the point of view of the author, a forum such as Vision-21 is becoming an essential component in the rather conservative climate in which our initiatives for space exploration are presently formed. Exchanges such as Vision-21 not only allows us to deviate from the 'by-the-book' approach and rediscover the ability and power in imagination, but provides for the discussion of ideas hitherto considered 'crazy' so that they may be given the change to transcend from the level of eccentricity to applicability.

  5. Measurement of the inclusive electron spectrum in charmless semileptonic B decays near the kinematic endpoint and determination of |Vub|

    CERN Document Server

    Aubert, B; Abrams, G S; Adye, T; Ahmed, S; Alam, M S; Albert, J; Aleksan, Roy; Allison, J; Allmendinger, T; Altenburg, D; Andreotti, M; Angelini, C; Anulli, F; Aston, D; Azzolini, V; Baak, M; Back, J J; Bailey, S; Baldini-Ferroli, R; Band, H R; Banerjee, Sw; Barate, R; Bard, D J; Barlow, N R; Barlow, R J; Barrett, M; Bartoldus, R; Batignani, G; Bauer, J M; Beck, T W; Behera, P K; Bellini, F; Benayoun, M; Berger, N; Bernard, D; Berryhill, J W; Best, D; Bettarini, S; Bettoni, D; Bevan, A J; Bhimji, W; Bianchi, F; Biasini, M; Blanc, F; Blaylock, G; Blinov, A E; Blinov, V E; Bloom, P; Bóna, M; Bondioli, M; Bonneaud, G R; Borgland, A W; Bosisio, L; Boutigny, D; Bowerman, D A; Boyarski, A M; Boyd, J T; Bozzi, C; Brandenburg, G; Brandt, T; Brau, J E; Breon, A B; Briand, H; Brochard, F; Brose, J; Brown, C L; Brown, C M; Brown, D; Brown, D N; Bruinsma, M; Brunet, S; Bucci, F; Buchanan, C; Buchmüller, O L; Bugg, W; Bulten, H; Burchat, Patricia R; Button-Shafer, J; Buzzo, A; Côté, D; Cahn, R N; 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LoSecco, J M; Lo Vetere, M; Lockman, W S; Lombardo, V; London, G W; Long, O; Lou, X C; Lu, A; Lü, C; Luitz, S; Luppi, E; Lusiani, A; Lüth, V; Lutz, A M; Lynch, G; Lynch, H L; Lyon, A J; MacFarlane, D B; Macri, M; Malcles, J; Mallik, U; Mancinelli, G; Mandelkern, M A; Manfredi, P F; Mangeol, D J J; Marchiori, G; Margoni, M; Marsiske, H; Martínez-Vidal, F; Mattison, T S; Mayer, B; Mazur, M A; Mazzoni, M A; McKenna, J A; McMahon, T R; Meadows, B T; Messner, R; Meyer, T I; Meyer, W T; Miftakov, V; Mihályi, A; Mir, L M; Mohanty, G B; Mohapatra, A K; Mommsen, R K; Monge, M R; Monorchio, D; Moore, T B; Morandin, M; Morgan, S E; Morganti, M; Morganti, S; Morii, M; Morton, G W; Muheim, F; Müller, D R; Müller-Pfefferkorn, R; Narsky, I; Nash, J A; Nauenberg, U; Neal, H; Negrini, M; Neri, N; Nesom, G; Nicholson, H; Nikolich, M B; Nogowski, R; O'Grady, C P; Ocariz, J; Oddone, P J; Ofte, I; Olaiya, E O; Olivas, A; Olsen, J; Onuchin, A P; Orimoto, T J; Otto, S; Ozcan, V E; Paar, H P; Paick, K; Palano, A; Palombo, F; Pan, Y; Panetta, J; Panvini, R S; Paoloni, E; Paolucci, P; Parry, R J; Passaggio, S; Patel, P M; Patrignani, C; Patteri, P; Payne, D J; Pelizaeus, M; Perazzo, A; Perl, M; Peruzzi, I M; Petersen, B A; Petersen, T C; Petrak, S; Petzold, A; Piatenko, T; Piccolo, D; Piccolo, M; Piemontese, L; Pierini, M; Pioppi, M; Piredda, G; Pivk, M; Plaszczynski, S; Playfer, S; Pompili, A; Poropat, P; Porter, F C; Posocco, M; Potter, C T; Prell, S; Prepost, R; Pripstein, M; Pulliam, T; Purohit, M V; Qi, N D; Rahatlou, S; Rahimi, A M; Rama, M; Rankin, P; Ratcliff, B N; Raven, G; Re, V; Reidy, J; Ricciardi, S; Richman, J D; Ritchie, J L; Rizzo, G; Roat, C; Roberts, D A; Robertson, S H; Robutti, E; Roe, N A; Röthel, W; Ronan, Michael T; Roney, J M; Rong, G; Roodman, A; Roos, L; Rosenberg, E I; Rotondo, M; Rubin, A E; Ryd, A; Saeed, M A; Safai-Tehrani, F; Saleem, M; Salnikov, A A; Salvatore, F; Samuel, A; Sanders, D A; Sandrelli, F; Santroni, A; Saremi, S; Sarti, A; Satpathy, A; Schalk, T; Schindler, R H; Schott, G; Schrenk, S; Schubert, J; Schubert, Klaus R; Schumm, B A; Schune, M H; Schwiening, J; Schwierz, R; Schwitters, R F; Sciacca, C; Sciolla, G; Seiden, A; Sekula, S J; Serednyakov, S I; Sharma, V; Shelkov, V G; Shen, B C; Simani, M C; Simi, G; Simonetto, F; Sinev, N B; Skovpen, Yu I; Sloane, R J; Smith, A J S; Smith, J G; Snoek, H L; Snyder, A; Sobie, R J; Soffer, A; Soha, A; Sokoloff, M D; Solodov, E P; Spaan, B; Spanier, S M; Spradlin, P; Stängle, H; Steinke, M; Stelzer, J; Stoker, D P; Stroili, R; Strom, D; Stugu, B; Su, D; Sullivan, M K; Summers, D J; Sundermann, J E; T'Jampens, S; Tan, P; Tantot, L; Taras, P; Taylor, F; Taylor, G P; Telnov, A V; Teodorescu, L; Ter-Antonian, R; Therin, G; Thiebaux, C; Thiessen, D; Tiozzo, G; Tisserand, V; Toki, W H; Torrence, E; Tosi, S; Touramanis, C; Treadwell, E; Vasileiadis, G; Vasseur, G; Vavra, J; Verderi, M; Verkerke, W; Vitale, L; Voci, C; Voena, C; Vuagnin, G; Wagner, G; Wagner, S R; Wagoner, D E; Waldi, R; Walsh, J; Wang, K; Wang, P; Wappler, F R; Watson, A T; Weaver, M; Weidemann, A W; Weinstein, A J R; Wenzel, W A; Wilden, L; Williams, D C; Williams, J C; Willocq, S; Wilson, F F; Wilson, J R; Wilson, M G; Wilson, R J; Winter, M A; Wisniewski, W J; Wittgen, M; Won, E; Wong, Q K; Wormser, G; Wright, D H; Wright, D M; Wu, J; Wu, S L; Xie, Y; Yamamoto, R K; Yang, S; Yarritu, A K; Ye, S; Yéche, C; Yi, J; Young, C C; Yu, Z; Yumiceva, F X; Yushkov, A N; Zallo, A; Zeng, Q; Zghiche, A; Zhang, J; Zhang, L; Zhao, H W; Zhu, Y S; Zito, M; De Sangro, R; Del Re, D; La Vaissière, C de

    2004-01-01

    We study the inclusive electron spectrum of B->X_u e nu decays near the kinematic limit for B->X_c e nu transitions using a sample of 88 million Upsilon(4S) decays recorded by the BABAR detector at the PEP II e+e- storage rings. For the electron momentum interval of 2.0 - 2.6 GeV/c the partial branching fraction is measured to be DeltaB(B->X_u e nu) = (0.480 +/- 0.029_{stat} +/- 0.053_{syst})x10^{-3}. Combining this result on with measurements of the inclusive photon spectrum in B->X_s gamma transition we find |V_ub|=(3.94 +/- 0.25_{exp} +/- 0.37_{f_u} +/- 0.19_{theory})x10^{-3}, where the first error represents the combined statistical and systematic experimental uncertainty of the partial branching fraction measurement, the second refers to the uncertainty of the determination of the fraction f_u of the inclusive electron spectrum that falls within our cuts, and the third error is due to theoretical uncertainties in the QCD corrections, plus the uncertainty in the b-quark mass. All results are preliminary.

  6. Formation of very hard electron and gamma-ray spectra of flat-spectrum radio quasars in the fast-cooling regime

    Science.gov (United States)

    Yan, Dahai; Zhang, Li; Zhang, Shuang-Nan

    2016-07-01

    In the external Compton scenario, we investigate the formation of a very hard electron spectrum in the fast-cooling regime, using a time-dependent emission model. It is shown that a very hard electron distribution, N^' }_e({γ ^' })∝ {γ ^' }^{-p}, with spectral index p ˜ 1.3 is formed below the minimum energy of injection electrons when inverse Compton scattering takes place in the Klein-Nishina regime, i.e. inverse Compton scattering of relativistic electrons on broad-line region radiation in flat-spectrum radio quasars. This produces a very hard gamma-ray spectrum and can explain in reasonable fashion the very hard Fermi-Large Area Telescope (LAT) spectrum of the flat-spectrum radio quasar 3C 279 during the extreme gamma-ray flare in 2013 December.

  7. Development of an Accommodation-Dependent Eye Model and Studying the Effects of Accommodation on Electron and Proton Dose Conversion Coefficients

    Directory of Open Access Journals (Sweden)

    Alireza Vejdani-Noghreiyan

    2016-06-01

    Full Text Available Introduction International Commission on Radiological Protection (ICRP has provided a comprehensive discussion on threshold dose for radiation-induced cataract in ICRP publication 116. Accordingly, various parts of the eye lens have different radio-sensitivities. Recently, some studies have been performed to develop a realistic eye model with the aim of providing accurate estimation of fluence-to-dose conversion coefficients for different parts of the eye. However, the effect of accommodation, which changes the lens shape and pupil size, on dose conversion coefficients has not been considered yet. In this study, we purport to develop an accommodation-dependent eye model and to study the effects of accommodation on the electron and proton fluence-to-dose conversion coefficients. Materials and Methods Herein, a modified eye model was developed by considering the effects of accommodation on the lens shape and pupil size. In addition, MCNPX 2.6 Monte Carlo transport code was used to calculate the effects of  eye lens accommodation on electron and proton fluence-to-dose conversion coefficients. Results Calculation of dose conversion coefficients demonstrated that the accommodation causes up to 40% discrepancy for fluence-to-dose conversion coefficients of electrons in the range of 600 to 800 keV, which is due to the change of eye lens shape during the accommodation of the eye. Conclusion Since the accommodation of the eye change the lens shape and pupil size, it has considerable effect on fluence-to-dose conversion coefficients of electrons at some ranges of incident particle energies that should be considered in simulation. However, the fluctuation of dose conversion coefficients of protons is negligible.

  8. Conversion of electronic to magnonic spin current at a heavy-metal magnetic-insulator interface

    Science.gov (United States)

    Wang, Xi-guang; Li, Zhi-xiong; Zhou, Zhen-wei; Nie, Yao-zhuang; Xia, Qing-lin; Zeng, Zhong-ming; Chotorlishvili, L.; Berakdar, J.; Guo, Guang-hua

    2017-01-01

    Electronic spin current is convertible to magnonic spin current via the creation or annihilation of thermal magnons at the interface of a magnetic insulator and a metal with a strong spin-orbital coupling. So far this phenomenon was evidenced in the linear regime. Based on analytical and full-fledged numerical results for the nonlinear regime we demonstrate that the generated thermal magnons or magnonic spin current in the insulator is asymmetric with respect to the charge current direction in the metal and exhibits a nonlinear dependence on the charge current density, which is explained by the tuning effect of the spin Hall torque and the magnetization damping. The results are also discussed in light of, and are in line with, recent experiments pointing to a new way of nonlinear manipulation of spin with electrical means.

  9. Thermodynamic consequence of the new attribution of bands in the electronic absorption spectrum of electron donor-iodine-solvent systems

    Science.gov (United States)

    Abramov, Sergey P.

    1999-06-01

    The subject review pays attention to the peculiarities in behaviour of bands in the electronic absorption spectra of electron donor-iodine-solvent systems, the appearance of which is associated with the intermolecular interaction of molecular iodine with electron donor organic molecules. The new concept of the bands’ attribution to the isomeric equilibrium molecular charge-transfer complexes (CTCs) of CTC-I and CTC-II types is considered. The features of possible phase transitions in the solid state are discussed on the basis of the thermodynamic properties and electronic structures of the CTC-I and CTC-II in electron donor-iodine-solvent systems. The stabilisation of the CTC-II structure with the temperature lowering coincided in many cases with the electrons’ localisation in the solid state structures having charge-transfer bonds.

  10. Detecting single atoms of calcium and iron in biological structures by electron energy-loss spectrum-imaging.

    Science.gov (United States)

    Leapman, R D

    2003-04-01

    As techniques for electron energy-loss spectroscopy (EELS) reach a higher degree of optimization, experimental detection limits for analysing biological structures are approaching values predicted by the physics of the electron scattering. Theory indicates that it should be possible to detect a single atom of certain elements like calcium and iron contained in a macromolecular assembly using a finely focused probe in the scanning transmission electron microscope (STEM). To test this prediction, EELS elemental maps have been recorded with the spectrum-imaging technique in a VG Microscopes HB501 STEM coupled to a Gatan Enfina spectrometer, which is equipped with an efficient charge-coupled device (CCD) array detector. By recording spectrum-images of haemoglobin adsorbed onto a thin carbon film, it is shown that the four heme groups in a single molecule can be detected with a signal-to-noise ratio of approximately 10 : 1. Other measurements demonstrate that calcium adsorbed onto a thin carbon film can be imaged at single atom sensitivity with a signal-to-noise ratio of approximately 5 : 1. Despite radiation damage due to the necessarily high electron dose, it is anticipated that mapping single atoms of metals and other bound elements will find useful applications in characterizing large protein assemblies.

  11. Two-Electron Energy Spectrum in a Parabolic Quantum Dot Under a Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    XIE Wen-Fang

    2003-01-01

    Two interacting electrons in a harmonic oscillator potential under the influence of a perpendicular homo-geneous magnetic field are considered. The energies of two-electron quantum dots with the electron-LO-phonon couplingas a function of magnetic field are calculated. Calculations are made by using the method of few-body physics withinthe effective-mass approximation. Our results show that the electron-LO-phonon coupling effect is very important insemiconductor quantum dots.

  12. Limiting efficiencies of solar energy conversion and photo-detection via internal emission of hot electrons and hot holes in gold

    CERN Document Server

    Boriskina, Svetlana V; Hsu, Wei-Chun; Liao, Bolin; Chen, Gang

    2015-01-01

    We evaluate the limiting efficiency of full and partial solar spectrum harvesting via the process of internal photoemission in Au-semiconductor Schottky junctions. Our results based on the ab initio calculations of the electron density of states (e-DOS) reveal that the limiting efficiency of the full-spectrum Au converter based on hot electron injection is below 4%. This value is even lower than previously established limit based on the parabolic approximation of the Au electron energy bands. However, we predict limiting efficiency exceeding 10% for the hot holes collection through the Schottky junction between Au and p-type semiconductor. Furthermore, we demonstrate that such converters have more potential if used as a part of the hybrid system for harvesting high- and low-energy photons of the solar spectrum.

  13. A novel method to quantify the emission and conversion of VOCs in the smoking of electronic cigarettes

    Science.gov (United States)

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2015-11-01

    An analytical technique was developed for the quantitation of volatile organic compounds (VOC) in three different forms of electronic cigarette (EC): solution, vapor, and aerosol. Through the application of the mass change tracking (MCT) approach, the consumed amount of the solution was measured to track the conversion of targets between the different phases. The concentration of aerosol plus vapor (A&V) decreased exponentially (559 to 129 g m-3) with increasing puff velocity (0.05 to 1 L min-1). A strong correlation existed between sampling volume and consumed solution mass (R2 = 0.9972 ± 0.0021 (n = 4)). In the EC solution, acetic acid was considerably high (25.8 μg mL-1), along with trace quantities of some VOCs (methyl ethyl ketone, toluene, propionic acid, and i-butyric acid: 0.24 ± 0.15 μg mL-1 (n = 4)). In the aerosol samples, many VOCs (n-butyraldehyde, n-butyl acetate, benzene, xylene, styrene, n-valeric acid, and n-hexanoic acid) were newly produced (138 ± 250 μg m-3). In general, the solution-to-aerosol (S/A) conversion was significant: e.g., 1,540% for i-butyric acid. The emission rates of all targets computed based on their mass in aerosol/ consumed solution (ng mL-1) were from 30.1 (p-xylene) to 398 (methyl ethyl ketone), while those of carboxyls were much higher from 166 (acetic acid) to 5,850 (i-butyric acid).

  14. Spectrum-splitting approach for Fermi-operator expansion in all-electron Kohn-Sham DFT calculations

    Science.gov (United States)

    Motamarri, Phani; Gavini, Vikram; Bhattacharya, Kaushik; Ortiz, Michael

    2017-01-01

    We present a spectrum-splitting approach to conduct all-electron Kohn-Sham density functional theory (DFT) calculations by employing Fermi-operator expansion of the Kohn-Sham Hamiltonian. The proposed approach splits the subspace containing the occupied eigenspace into a core subspace, spanned by the core eigenfunctions, and its complement, the valence subspace, and thereby enables an efficient computation of the Fermi-operator expansion by reducing the expansion to the valence-subspace projected Kohn-Sham Hamiltonian. The key ideas used in our approach are as follows: (i) employ Chebyshev filtering to compute a subspace containing the occupied states followed by a localization procedure to generate nonorthogonal localized functions spanning the Chebyshev-filtered subspace; (ii) compute the Kohn-Sham Hamiltonian projected onto the valence subspace; (iii) employ Fermi-operator expansion in terms of the valence-subspace projected Hamiltonian to compute the density matrix, electron density, and band energy. We demonstrate the accuracy and performance of the method on benchmark materials systems involving silicon nanoclusters up to 1330 electrons, a single gold atom, and a six-atom gold nanocluster. The benchmark studies on silicon nanoclusters revealed a staggering fivefold reduction in the Fermi-operator expansion polynomial degree by using the spectrum-splitting approach for accuracies in the ground-state energies of ˜10-4Ha/atom with respect to reference calculations. Further, numerical investigations on gold suggest that spectrum splitting is indispensable to achieve meaningful accuracies, while employing Fermi-operator expansion.

  15. Thermal conversion of electronic and electrical properties of AuCl3-doped single-walled carbon nanotubes.

    Science.gov (United States)

    Yoon, Seon-Mi; Kim, Un Jeong; Benayad, Anass; Lee, Il Ha; Son, Hyungbin; Shin, Hyeon-Jin; Choi, Won Mook; Lee, Young Hee; Jin, Yong Wan; Lee, Eun-Hong; Lee, Sang Yoon; Choi, Jae-Young; Kim, Jong Min

    2011-02-22

    By using carbon-free inorganic atomic layer involving heat treatment from 150 to 300 °C, environmentally stable and permanent modulation of the electronic and electrical properties of single-walled carbon nanotubes (SWCNTs) from p-type to ambi-polar and possibly to n-type has been demonstrated. At low heat treatment temperature, a strong p-doping effect from Au(3+) ions to CNTs due to a large difference in reduction potential between them is dominant. However at higher temperature, the gold species are thermally reduced, and thermally induced CNT-Cl finally occurs by the decomposition reaction of AuCl(3). Thus, in the AuCl(3)-doped SWCNTs treated at higher temperature, the p-type doping effect is suppressed and an n-type property from CNT-Cl is thermally induced. Thermal conversion of the majority carrier type of AuCl(3)-doped SWNTs is systematically investigated by combining various optical and electrical tools.

  16. Vibrational vs. electronic coherences in 2D spectrum of molecular systems

    CERN Document Server

    Butkus, Vytautas; Valkunas, Leonas; Abramavicius, Darius

    2012-01-01

    The two-dimensional spectroscopy has recently revealed oscillatory behavior of excitation dynamics in molecular systems. However, in the majority of cases it is strongly debated if excitonic or vibrational wavepackets, or evidences of quantum transport have been observed. In this letter, the method for distinguishing between vibrational and excitonic wavepacket motion is presented, based on the phase and amplitude relationships of oscillations of distinct peaks, which has been revealed using fundamental analysis of two-dimensional spectrum of two representative systems.

  17. Energy spectrum of an electron confined in the hexagon-shaped quantum well

    Institute of Scientific and Technical Information of China (English)

    Yu.; V.; VOROBIEV; V.; R.; VIEIRA; P.; P.; HORLEY; P.; N.; GORLEY; J.; GONZLEZ-HERNNDEZ

    2009-01-01

    Considering the hexagonal-shaped quantum-scale formations on the surface of thin semiconductor films, a methodology was developed to obtain the analytical solution of the Schrdinger equation when impenetrable walls of a quantum well are treated as mirrors. The results obtained allowed the calculation of the space probability distributions and the energy spectrum of the particle confined in a hex-agonal-shaped well.

  18. Energy spectrum of an electron confined in the hexagon-shaped quantum well

    Institute of Scientific and Technical Information of China (English)

    Yu.V.VOROBIEV; V.R.VlEIRA; P.P.HORLEY; P.N.GORLEY; J.GONZ(A)LEZ-HERN(A)NDEZ

    2009-01-01

    Considering the hexagonal-shaped quantum-scale formations on the surface of thin semiconductor films, a methodology was developed to obtain the analytical solution of the Schr(o)dinger equation when impenetrable walls of a quantum well are treated as mirrors. The results obtained allowed the calcula-tion of the space probability distributions and the energy spectrum of the particle confined in a hex-agonal-shaped well.

  19. Spectrum of fast electrons in a dense gas in the presence of a nonuniform pulsed field

    Science.gov (United States)

    Tkachev, A. N.; Yakovlenko, S. I.

    2007-01-01

    The problems of gas preionization in discharges related to laser physics are considered. The propagation of fast electrons injected from the cathode in the presence of a nonuniform nonstationary field and the motion of multiplying electrons at the edge of the avalanche in the presence of a nonuniform nonstationary field are simulated. The effect of the voltage pulse steepness and the field nonuniformity on the mean propagation velocity of fast electrons and their energy distribution is demonstrated. At certain combinations of the voltage pulse rise time and amplitude and at a certain time interval, the center of gravity of the electron cloud can move in the opposite direction relative to the direction of force acting upon electrons. It is also demonstrated that the number of hard particles (and, hence, the hard component of the x-ray bremsstrahlung) increases with both an increase in the voltage amplitude and a decrease in the pulse rise time. For nonoptimal conditions of the picosecond voltage pulse, an assumption is formulated: an electron beam in gas is formed due to the electrons at the edge of the avalanche rather than the background multiplication wave approaching the anode.

  20. Theoretical study on S1(1B3u) state electronic structure and absorption spectrum of pyrazine

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Making use of a set of quantum chemistry methods, the harmonic potential surfaces of the ground state (S0(1Ag)) and the first (S1(1B3u)) excited state of pyrazine are investigated, and the electronic structures of the two states are characterized. In the present study, the conventional quantum mechanical method, taking account of the Born-Oppenheimer adiabatic approximation, is adopted to simulate the absorp-tion spectrum of S1(1B3u) state of pyrazine. The assignment of main vibronic transitions is made for S1(1B3u) state. It is found that the spectral profile is mainly described by the Franck-Condon progression of totally symmetric mode ν6a. For the five totally symmetric modes, the present calculations show that the frequency differences between the ground and the S1(1B3u) state are small. Therefore the displaced harmonic oscillator approximation along with Franck-Condon transition is used to simulate S1(1B3u) absorption spectra. The distortion effect due to the so-called quadratic coupling is demonstrated to be unimportant for the absorption spectrum, except the coupling mode ν10a. The calculated S1(1B3u) ab-sorption spectrum is in reasonable agreement with the experimental spectra.

  1. Theoretical study on S1(1B3u) state electronic structure and absorption spectrum of pyrazine

    Institute of Scientific and Technical Information of China (English)

    HE RongXing; ZHU ChaoYuan; CHIN Chih-Hao; LIN Sheng-Hsien

    2008-01-01

    Making use of a set of quantum chemistry methods, the harmonic potential surfaces of the ground state (S0(1Ag)) and the first (S1(1B3u)) excited state of pyrazine are investigated, and the electronic structures of the two states are characterized. In the present study, the conventional quantum mechanical method, taking account of the Born-Oppenheimer adiabatic approximation, is adopted to simulate the absorp-tion spectrum of S1(1B3u) state of pyrazine. The assignment of main vibronic transitions is made for S1(1B3u) state. It is found that the spectral profile is mainly described by the Franck-Condon progression of totally symmetric mode v6a. For the five totally symmetric modes, the present calculations show that the frequency differences between the ground and the S1(1B3u) state are small. Therefore the displaced harmonic oscillator approximation along with Franck-Condon transition is used to simulate S1(1B3u)absorption spectra. The distortion effect due to the so-called quadratic coupling is demonstrated to be unimportant for the absorption spectrum, except the coupling mode v10a. The calculated S1(1B3u) ab-sorption spectrum is in reasonable agreement with the experimental spectra.

  2. Realization and Comparison of Several Regression Algorithms for Electron Energy Spectrum Reconstruction

    Institute of Scientific and Technical Information of China (English)

    LI Gui; LIN Hui; WU Ai-Dong; SONG Gang; WU Yi-Can

    2008-01-01

    To determine the electron energy spectra for medical accelerator effectively, we investigate a nonlinear programming model with several nonlinear regression algorithms, including Levenberg-Marquardt, Quasi-Newton, Gradient, Conjugate Gradient, Newton, Principal-Axis and NMinimize algorithms. The local relaxation-bound method is also developed to increase the calculation accuracy. The testing results demonstrate that the above methods could reconstruct the electron energy spectra effectively. Especially, further with the local relaxationbound method the Levenberg Marquardt, Newton and N Minimize algorithms could precisely obtain both the electron energy spectra and the photon contamination. Further study shows that ignoring about 4% photon contamination would increase error greatly, and it also inaccurately makes the electron energy spectra 'drift' to the low energy.

  3. THE HIGH-RESOLUTION EXTREME-ULTRAVIOLET SPECTRUM OF N{sub 2} BY ELECTRON IMPACT

    Energy Technology Data Exchange (ETDEWEB)

    Heays, A. N. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Ajello, J. M.; Aguilar, A. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Lewis, B. R.; Gibson, S. T., E-mail: heays@strw.leidenuniv.nl [Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)

    2014-04-01

    We have analyzed high-resolution (FWHM = 0.2 Å) extreme-ultraviolet (EUV, 800-1350 Å) laboratory emission spectra of molecular nitrogen excited by an electron impact at 20 and 100 eV under (mostly) optically thin, single-scattering experimental conditions. A total of 491 emission features were observed from N{sub 2} electronic-vibrational transitions and atomic N I and N II multiplets and their emission cross sections were measured. Molecular emission was observed at vibrationally excited ground-state levels as high as v'' = 17, from the a {sup 1}Π {sub g} , b {sup 1}Π {sub u} , and b'{sup 1}Σ {sub u} {sup +} excited valence states and the Rydberg series c'{sub n} {sub +1} {sup 1}Σ {sub u} {sup +}, c{sub n} {sup 1}Π {sub u} , and o{sub n} {sup 1}Π {sub u} for n between 3 and 9. The frequently blended molecular emission bands were disentangled with the aid of a sophisticated and predictive quantum-mechanical model of excited states that includes the strong coupling between valence and Rydberg electronic states and the effects of predissociation. Improved model parameters describing electronic transition moments were obtained from the experiment and allowed for a reliable prediction of the vibrationally summed electronic emission cross section, including an extrapolation to unobserved emission bands and those that are optically thick in the experimental spectra. Vibrationally dependent electronic excitation functions were inferred from a comparison of emission features following 20 and 100 eV electron-impact collisional excitation. The electron-impact-induced fluorescence measurements are compared with Cassini Ultraviolet Imaging Spectrograph observations of emissions from Titan's upper atmosphere.

  4. Photodissociation of carbon dioxide in singlet valence electronic states. II. Five state absorption spectrum and vibronic assignment

    Science.gov (United States)

    Grebenshchikov, Sergy Yu.

    2013-06-01

    The absorption spectrum of CO2 in the wavelength range 120-160 nm is analyzed by means of quantum mechanical calculations performed using vibronically coupled potential energy surfaces of five singlet valence electronic states and the coordinate dependent transition dipole moment vectors. The thermally averaged spectrum, calculated for T = 190 K via Boltzmann averaging of optical transitions from many initial rotational states, accurately reproduces the experimental spectral envelope, consisting of a low and a high energy band, the positions of the absorption maxima, their FWHMs, peak intensities, and frequencies of diffuse structures in each band. Contributions of the vibronic interactions due to Renner-Teller coupling, conical intersections, and the Herzberg-Teller effect are isolated and the calculated bands are assigned in terms of adiabatic electronic states. Finally, diffuse structures in the calculated bands are vibronically assigned using wave functions of the underlying resonance states. It is demonstrated that the main progressions in the high energy band correspond to consecutive excitations of the pseudorotational motion along the closed loop of the CI seam, and progressions differ in the number of nodes along the radial mode perpendicular to the closed seam. Irregularity of the diffuse peaks in the low energy band is interpreted as a manifestation of the carbene-type "cyclic" OCO minimum.

  5. Optimization of metallic magnetic calorimeters for high resolution measurement of the {sup 163}Ho electron capture spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Haehnle, Sebastian [Kirchhoff-Institute for Physics, Heidelberg University (Germany); Collaboration: ECHo-Collaboration

    2015-07-01

    The absolute scale of the neutrino mass eigenstates is one of the puzzles in modern particle physics. One method to investigate the value of the electron neutrino mass is to analyse the high energy region of the {sup 163}Ho electron capture spectrum. In the ECHo experiment low temperature metallic magnetic calorimeters (MMCs) are used for the calorimetric measurements of the EC spectrum of {sup 163}Ho. To ensure 100% quantum efficiency, the {sup 163}Ho ions are implanted into the gold absorber. Experiments carried out with a first detector prototype have demonstrated that MMC-based detectors fulfill the requirements in terms of energy resolution, rise-time and energy calibration. We discuss methods to further optimize the performance of MMCs with implanted {sup 163}Ho. Our aim is to achieve an energy resolution Δ E{sub FWHM} < 5 eV and a signal rise-time τ < 100 ns. An important aspect of this optimization is to define the maximum activity per pixel. This will result from a compromise between allowed unresolved pile-up fraction, additional heat capacity in the absorber due to Ho ions in the absorber material and minimization of the pixel number. We discuss experimental approaches for the determination of the optimal activity per pixel.

  6. Study of the molecular structure, ionization spectrum, and electronic wave function of 1,3-butadiene using electron momentum spectroscopy and benchmark Dyson orbital theories

    Science.gov (United States)

    Deleuze, M. S.; Knippenberg, S.

    2006-09-01

    The scope of the present work is to reconcile electron momentum spectroscopy with elementary thermodynamics, and refute conclusions drawn by Saha et al. in J. Chem. Phys. 123, 124315 (2005) regarding fingerprints of the gauche conformational isomer of 1,3-butadiene in electron momentum distributions that were experimentally inferred from gas phase (e,2e) measurements on this compound [M. J. Brunger et al., J. Chem. Phys. 108, 1859 (1998)]. Our analysis is based on thorough calculations of one-electron and shake-up ionization spectra employing one-particle Green's function theory along with the benchmark third-order algebraic diagrammatic construction [ADC(3)] scheme. Accurate spherically averaged electron momentum distributions are correspondingly computed from the related Dyson orbitals. The ionization spectra and Dyson orbital momentum distributions that were computed for the trans-conformer of 1,3-butadiene alone are amply sufficient to quantitatively unravel the shape of all available experimental (e,2e) electron momentum distributions. A comparison of theoretical ADC(3) spectra for the s-trans and gauche energy minima with inner- and outer-valence high-resolution photoelectron measurements employing a synchrotron radiation beam [D. M. P. Holland et al., J. Phys. B 29, 3091 (1996)] demonstrates that the gauche structure is incompatible with ionization experiments in high-vacuum conditions and at standard temperatures. On the other hand, outer-valence Green's function calculations on the s-trans energy minimum form and approaching basis set completeness provide highly quantitative insights, within ˜0.2eV accuracy, into the available experimental one-electron ionization energies. At last, analysis of the angular dependence of relative (e,2e) ionization intensities nicely confirms the presence of one rather intense π-2 π*+1 satellite at ˜13.1eV in the ionization spectrum of the s-trans conformer.

  7. Spectrum-dose conversion operator of NaI(Tl) and CsI(Tl) scintillation detectors for air dose rate measurement in contaminated environments.

    Science.gov (United States)

    Tsuda, Shuichi; Saito, Kimiaki

    2017-01-01

    Spectrum-dose conversion operators, the G(E) functions, for common NaI(Tl) scintillation survey meters and CsI(Tl) detectors are obtained for measurements in a semi-infinite plane of contaminated ground field by photon-emitting radionuclides (ground source). The calculated doses at a height of 100 cm from the ground in (137)Cs-contaminated environments by the Monte Carlo simulation technique are compared with those obtained using the G(E) functions by assuming idealized irradiation geometries such as anterior-posterior or isotropic. The simulation reveals that one could overestimate air dose rates in the environment by a maximum of 20-30% for NaI(Tl) detectors and 40-50% for CsI(Tl) detectors depending on photon energy when using the G(E) functions assuming idealized irradiation geometries for ground source measurements. Measurements obtained after the nuclear accident in Fukushima reveal that the doses calculated using a G(E) function for a unidirectional irradiation geometry are 1.17 times higher than those calculated using a G(E) function for the ground source in the case of a CsI(Tl) scintillation detector, which has a rectangular parallelepiped crystal (13 × 13 × 20 mm(3)). However, if a G(E) function is used assuming irradiation to a surface of the detector, the doses agree with those of the ground source within 2%. These results indicate that in contaminated environments, the commonly used scintillation-based detectors overestimate doses within the acceptable limit. In addition, the degree of overestimation depends on the irradiation direction of each detector assumed for developing the G(E) function. With regard to directional dependence of the detectors, reliable air dose rates in the environment can be obtained using the G(E) function determined in unidirectional irradiation geometry, provided that the irradiation surface of the crystal is determined properly. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Time-dependent density functional study of the electronic potential energy curves and excitation spectrum of the oxygen molecule.

    Science.gov (United States)

    Guan, Jingang; Wang, Fan; Ziegler, Tom; Cox, Hazel

    2006-07-28

    Orbital energies, ionization potentials, molecular constants, potential energy curves, and the excitation spectrum of O(2) are calculated using time-dependent density functional theory (TDDFT) with Tamm-Dancoff approximation (TDA). The calculated negative highest occupied molecular orbital energy (-epsilon(HOMO)) is compared with the energy difference ionization potential for five exchange correlation functionals consisting of the local density approximation (LDAxc), gradient corrected Becke exchange plus Perdew correlation (B(88X)+P(86C)), gradient regulated asymptotic correction (GRAC), statistical average of orbital potentials (SAOP), and van Leeuwen and Baerends asymptotically correct potential (LB94). The potential energy curves calculated using TDDFT with the TDA at internuclear distances from 1.0 to 1.8 A are divided into three groups according to the electron configurations. The 1pi(u) (4)1pi(g) (2) electron configuration gives rise to the X (3)Sigma(g) (-), a (1)Delta(g), and b (1)Sigma(g) (+) states; the 1pi(u) (3)1pi(g) (3) electron configuration gives rise to the c (1)Sigma(u) (-), C (3)Delta(u), and A (3)Sigma(u) (+) states; and the B (3)Sigma(u) (-), A (1)Delta(u), and f (1)Sigma(u) (+) states are determined by the mixing of two or more electron configurations. The excitation spectrum of the oxygen molecule, calculated with the aforementioned exchange correlation functionals, shows that the results are quite sensitive to the choice of functional. The LDAxc and the B(88X)+P(86C) functionals produce similar spectroscopic patterns with a single strongly absorbing band positioned at 19.82 and 19.72 eV, respectively, while the asymptotically corrected exchange correlation functionals of the SAOP and the LB94 varieties yield similar excitation spectra where the computed strongly absorbing band is located at 16.09 and 16.42 eV, respectively. However, all of the exchange correlation functionals yield only one strongly absorbing band (oscillator strength

  9. Photoabsorption Spectrum and Optically Forbidden Transitions of Krypton by Electron Impact

    Institute of Scientific and Technical Information of China (English)

    苑震生; 朱林繁; 李文斌; 成华东; 徐克尊

    2002-01-01

    A high resolution fast electron energy loss spectrometer with multi-channel energy analysis was employed. The maxima just above the threshold 4p-1(2P1/2), which is regarded as a shape resonance, was obtained at 16.3 eV. The optically forbidden excitations of 4s electron were measured for the first time, and the energy positions are 23.75 eV(4s-15s), 25.66 eV (4s-16s/4d) and 26.60 eV(4s-17s/5d).

  10. Initial implementation of the conversion from the energy-subtracted CT number to electron density in tissue inhomogeneity corrections: An anthropomorphic phantom study of radiotherapy treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Tsukihara, Masayoshi [Division of Radiological Technology, Graduate School of Health Sciences, Niigata University, Niigata 951-8518 (Japan); Noto, Yoshiyuki [Department of Radiology, Niigata University Medical and Dental Hospital, Niigata 951-8520 (Japan); Sasamoto, Ryuta; Hayakawa, Takahide; Saito, Masatoshi, E-mail: masaito@clg.niigata-u.ac.jp [Department of Radiological Technology, School of Health Sciences, Faculty of Medicine, Niigata University, Niigata 951-8518 (Japan)

    2015-03-15

    Purpose: To achieve accurate tissue inhomogeneity corrections in radiotherapy treatment planning, the authors had previously proposed a novel conversion of the energy-subtracted computed tomography (CT) number to an electron density (ΔHU–ρ{sub e} conversion), which provides a single linear relationship between ΔHU and ρ{sub e} over a wide range of ρ{sub e}. The purpose of this study is to present an initial implementation of the ΔHU–ρ{sub e} conversion method for a treatment planning system (TPS). In this paper, two example radiotherapy plans are used to evaluate the reliability of dose calculations in the ΔHU–ρ{sub e} conversion method. Methods: CT images were acquired using a clinical dual-source CT (DSCT) scanner operated in the dual-energy mode with two tube potential pairs and an additional tin (Sn) filter for the high-kV tube (80–140 kV/Sn and 100–140 kV/Sn). Single-energy CT using the same DSCT scanner was also performed at 120 kV to compare the ΔHU–ρ{sub e} conversion method with a conventional conversion from a CT number to ρ{sub e} (Hounsfield units, HU–ρ{sub e} conversion). Lookup tables for ρ{sub e} calibration were obtained from the CT image acquisitions for tissue substitutes in an electron density phantom (EDP). To investigate the beam-hardening effect on dosimetric uncertainties, two EDPs with different sizes (a body EDP and a head EDP) were used for the ρ{sub e} calibration. Each acquired lookup table was applied to two radiotherapy plans designed using the XiO TPS with the superposition algorithm for an anthropomorphic phantom. The first radiotherapy plan was for an oral cavity tumor and the second was for a lung tumor. Results: In both treatment plans, the performance of the ΔHU–ρ{sub e} conversion was superior to that of the conventional HU–ρ{sub e} conversion in terms of the reliability of dose calculations. Especially, for the oral tumor plan, which dealt with dentition and bony structures, treatment

  11. Engagement with Electronic Screen Media among Students with Autism Spectrum Disorders

    Science.gov (United States)

    Mineo, Beth A.; Ziegler, William; Gill, Susan; Salkin, Donna

    2009-01-01

    This study investigated the relative engagement potential of four types of electronic screen media (ESM): animated video, video of self, video of a familiar person engaged with an immersive virtual reality (VR) game, and immersion of self in the VR game. Forty-two students with autism, varying in age and expressive communication ability, were…

  12. Ion gyro-harmonic structuring in the stimulated radiation spectrum and optical emissions during electron gyro-harmonic heating

    Science.gov (United States)

    Mahmoudian, A.; Scales, W. A.; Bernhardt, P. A.; Samimi, A.; Kendall, E.; Ruohoniemi, J. M.; Isham, B.; Vega-Cancel, O.; Bordikar, M.

    2013-03-01

    Stimulated electromagnetic emissions (SEEs) are secondary radiation produced during active space experiments in which the ionosphere is actively heated with high power high frequency (HF) ground-based radio transmitters. Recently, there has been significant interest in ion gyro-harmonic structuring the SEE spectrum due to the potential for new diagnostic information available such as electron acceleration and creation of artificial ionization layers. These relatively recently discovered gyro-harmonic spectral features have almost exclusively been studied when the transmitting frequency is near the second electron gyro-harmonic frequency. The first extensive systematic experimental investigations of the possibility of these spectral features for third electron gyro-harmonic heating are provided here. Discrete spectral features shifted from the transmit frequency ordered by harmonics of the ion gyro-frequency were observed for third electron gyro-harmonic heating for the first time at a recent campaign at the High Frequency Active Auroral Research Program (HAARP) facility. These features were also closely correlated with a broader band feature at a larger frequency shift from the transmit frequency known as the downshifted peak (DP). The power threshold of these spectral features was measured, as well as their behavior with heater beam angle, and proximity of the transmit frequency to the third electron gyro-harmonic frequency. Comparisons were also made with similar spectral features observed during second electron gyro-harmonic heating during the same campaign. A theoretical model is provided that interprets these spectral features as resulting from parametric decay instabilities in which the pump field ultimately decays into high frequency upper hybrid/electron Bernstein and low frequency neutralized ion Bernstein IB and/or obliquely propagating ion acoustic waves at the upper hybrid interaction altitude. Coordinated optical and SEE observations were carried out

  13. Shock Protection of Portable Electronic Products: Shock Response Spectrum, Damage Boundary Approach, and Beyond

    Directory of Open Access Journals (Sweden)

    Suresh Goyal

    1997-01-01

    Full Text Available The pervasive shock response spectrum (SRS and damage boundary methods for evaluating product fragility and designing external cushioning for shock protection are described in detail with references to the best available literature. Underlying assumptions are carefully reviewed and the central message of the SRS is highlighted, particularly as it relates to standardized drop testing. Shortcomings of these methods are discussed, and the results are extended to apply to more general systems. Finally some general packaging and shock-mounting strategies are discussed in the context of protecting a fragile disk drive in a notebook computer, although the conclusions apply to other products as well. For example, exterior only cushioning (with low restitution to reduce subsequent impacts will provide a slenderer form factor than the next best strategy: interior cushioning with a “dead” hard outer shell.

  14. Vibronic Characteristics and Spin-Density Distributions in Bacteriochlorins as Revealed by Spectroscopic Studies of 16 Isotopologues. Implications for Energy- and Electron-Transfer in Natural Photosynthesis and Artificial Solar-Energy Conversion.

    Science.gov (United States)

    Diers, James R; Tang, Qun; Hondros, Christopher J; Chen, Chih-Yuan; Holten, Dewey; Lindsey, Jonathan S; Bocian, David F

    2014-06-26

    Vibronic characteristics and spin-density distributions in the core bacteriochlorin macrocycle were revealed by spectroscopic and theoretical studies of 16 isotopologues. The vibrational modes in copper bacteriochlorin isotopologues were examined via resonance Raman and Fourier-transform infrared spectroscopy. The resonance Raman spectra exhibit an exceptional sparcity of vibronically active modes of the core macrocycle, in contrast with the rich spectra of the natural bacteriochlorophylls. The Qy-excitation resonance Raman spectrum is dominated by a single mode at 727 cm(-1), which calculations suggest is due to a symmetrical accordion-like deformation of the five-atom Cm(CaNCa)pyrroleCm portion of the ring core. This deformation also dominates the vibronic features in the absorption and fluorescence spectra. The spin-density distributions in the π-cation radical of the zinc bacteriochlorin isotopologues were studied by electron paramagnetic resonance spectroscopy. The spectra indicate a significant electron/spin density (ρ ∼ 0.1) on each meso-carbon atom. This observation contradicts the predictions of early calculations that have been assumed to be correct for nearly four decades. Collectively, these findings have implications for how the structural features that characterize natural bacteriochlorophylls might influence energy- and electron-transfer processes in photosynthesis and alter the thinking on the design of synthetic, bacteriochlorin-based arrays for solar-energy conversion.

  15. CaS∶Eu,Sm及其在农用转光膜上的应用原理%APPLICATION PRINCIPLE OF ELECTRON TRAPPING MATERIAL CaS∶Eu,Sm IN THE LIGHT CONVERSION AGRICULTURAL FILM

    Institute of Scientific and Technical Information of China (English)

    叶孔敦; 光昭; 范文慧

    2001-01-01

    Electron trapping material CaS∶Eu,Sm has been prepared by the technique of rare earth doping directly.It can not only possess the fluorescent characteristics of CaS∶Eu,but also convert infrared light (0.8~1.6μm) to visible light (~672nm) and its quantum efficiency is more than 76%.According to the solar spectra and the best spectrum of plant growth as well as the fluorescence spectrum of CaS∶Eu,Sm,it is explained that CaS∶Eu,Sm phosphor is good additive of the light conversion agricultural film.Moreover,the absorption spectrum of chlorophyll photosynthesis can be imitated and infrared light can be converted to visible light by the light conversion agricultural film if CaS∶Eu2+,Sm3+,Cu+ phosphor is used as additive,so it may be thought that CaS∶Eu2+,Sm3+,Cu+ phosphor is better than CaS∶Eu2+,Cu+ phosphor as additive in the light conversion agricultural film.%利用稀土直接掺杂工艺合成了一种“常光充能”型电子陷获材料CaS∶Eu,Sm,它不仅具有CaS∶Eu无机发光材料的荧光光谱特性,而且具有红外升频转换特性,可将0.8~ 1.6μm的红外光直接转换为~672nm的红光、量子效率高达76%,是一种优于CaS∶Eu的光转换农膜添加剂.而共掺Eu2+、Sm3+和Cu+的CaS荧光粉有望成为一种性能优于光转换农膜添加剂CaS∶Eu2+,Cu+、可人工模拟叶绿素吸收光谱的新型农用转光膜材料.

  16. Parallel implementation of electronic structure eigensolver using a partitioned folded spectrum method

    CERN Document Server

    Briggs, E L; Bernholc, J

    2015-01-01

    A parallel implementation of an eigensolver designed for electronic structure calculations is presented. The method is applicable to computational tasks that solve a sequence of eigenvalue problems where the solution for a particular iteration is similar but not identical to the solution from the previous iteration. Such problems occur frequently when performing electronic structure calculations in which the eigenvectors are solutions to the Kohn-Sham equations. The eigenvectors are represented in some type of basis but the problem sizes are normally too large for direct diagonalization in that basis. Instead a subspace diagonalization procedure is employed in which matrix elements of the Hamiltonian operator are generated and the eigenvalues and eigenvectors of the resulting reduced matrix are obtained using a standard eigensolver from a package such as LAPACK or SCALAPACK. While this method works well and is widely used, the standard eigensolvers scale poorly on massively parallel computer systems for the m...

  17. Quantum Geometry: Relativistic energy approach to cooperative electron-nucleary-transition spectrum

    Directory of Open Access Journals (Sweden)

    Ольга Юрьевна Хецелиус

    2014-11-01

    Full Text Available An advanced relativistic energy approach is presented and applied to calculating parameters of electron-nuclear 7-transition spectra of nucleus in the atom. The intensities of the spectral satellites are defined in the relativistic version of the energy approach (S-matrix formalism, and gauge-invariant quantum-electrodynamical perturbation theory with the Dirac-Kohn-Sham density-functional zeroth approximation.

  18. The Energy Spectrum of Accelerated Electrons from Wave-Plasma Interactions in the Ionosphere

    Science.gov (United States)

    2012-06-29

    STATEMENT Distribution A: Approved for public release; distribution is unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT A HAARP ...data was obtained. It was therefore necessary to find the resources to repeat the campaign effort (see budget below). A HAARP campaign was...were highly structured in space and time. This fact, and the lack of electron temperature data at HAARP , made data analysis difficult. It became

  19. Identification of a millisecond isomeric state in {sup 129}Cd{sub 81} via the detection of internal conversion and Compton electrons

    Energy Technology Data Exchange (ETDEWEB)

    Taprogge, J. [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Departamento de Física Teórica, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Jungclaus, A., E-mail: andrea.jungclaus@csic.es [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Grawe, H. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Nishimura, S.; Xu, Z.Y.; Doornenbal, P.; Lorusso, G. [RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Nácher, E. [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Simpson, G.S. [LPSC, Université Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut National Polytechnique de Grenoble, F-38026 Grenoble cedex (France); Söderström, P.-A. [RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Sumikama, T. [Department of Physics, Tohoku University, Aoba, Sendai, Miyagi 980-8578 (Japan); Baba, H. [RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Browne, F. [School of Computing, Engineering and Mathematics, University of Brighton, Brighton BN2 4JG (United Kingdom); RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Fukuda, N. [RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Gernhäuser, R. [Physik Department E12, Technische Universität München, D-85748 Garching (Germany); and others

    2014-11-10

    The decay of an isomeric state in the neutron-rich nucleus {sup 129}Cd has been observed via the detection of internal conversion and Compton electrons providing first experimental information on excited states in this nucleus. The isomer was populated in the projectile fission of a {sup 238}U beam at the Radioactive Isotope Beam Factory at RIKEN. From the measured yields of γ-rays and internal conversion electrons, a multipolarity of E3 was tentatively assigned to the isomeric transition. A half-life of T{sub 1/2}=3.6(2) ms was determined for the new state which was assigned a spin of (21/2{sup +}), based on a comparison to shell model calculations performed using state-of-the-art realistic effective interactions.

  20. Phonon spectrum, electron spin-lattice relaxation and spin-phonon coupling of Cu2+ ions in BaF2 crystal

    Science.gov (United States)

    Hoffmann, Stanislaw K.; Lijewski, Stefan

    2015-03-01

    Electron spin-lattice relaxation rate is determined by electron spin echo method in temperature range 4-60 K. The Raman relaxation processes dominate and its theory is outlined in a form suitable for calculations of relaxation rate using real phonon spectrum. A few approximations have been considered: when phonon spectrum and Debye temperature are not available; when Debye temperature is available but phonon spectrum is not; and when spin-phonon coupling is known. All these approximations use the Debye model of phonons and give a non-satisfactory description the temperature dependence of the relaxation rate. A perfect description of experimental results is obtained when real phonon spectrum is considered. The value of the spin-phonon coupling parameter was determined as G = = 1362cm-1 . This value is discussed by a comparison with G-values published for various ions and crystals.

  1. A fresh look at the photoelectron spectrum of bromobenzene: A third-order non-Dyson electron propagator study

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M.; Wormit, M.; Dreuw, A. [Interdisciplinary Center for Scientific Computing, University of Heidelberg, Im Neuenheimer Feld 368, D-69120 Heidelberg (Germany); Soshnikov, D. Yu.; Trofimov, A. B., E-mail: abtrof@mail.ru [Favorsky’s Institute of Chemistry, SB RAS, 664033 Irkutsk (Russian Federation); Laboratory of Quantum Chemistry, Irkutsk State University, 664003 Irkutsk (Russian Federation); Holland, D. M. P. [Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom); Powis, I., E-mail: ivan.powis@nottingham.ac.uk [School of Chemistry, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Antonsson, E.; Patanen, M.; Nicolas, C.; Miron, C. [Synchrotron Soleil, L’Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette Cedex (France)

    2015-10-14

    The valence-shell ionization spectrum of bromobenzene, as a representative halogen substituted aromatic, was studied using the non-Dyson third-order algebraic-diagrammatic construction [nD-ADC(3)] approximation for the electron propagator. This method, also referred to as IP-ADC(3), was implemented as a part of the Q-Chem program and enables large-scale calculations of the ionization spectra, where the computational effort scales as n{sup 5} with respect to the number of molecular orbitals n. The IP-ADC(3) scheme is ideally suited for investigating low-lying ionization transitions, so fresh insight could be gained into the cationic state manifold of bromobenzene. In particular, the present IP-ADC(3) calculations with the cc-pVTZ basis reveal a whole class of low-lying low-intensity two-hole-one-particle (2h-1p) doublet and quartet states, which are relevant to various photoionization processes. The good qualitative agreement between the theoretical spectral profile for the valence-shell ionization transitions generated with the smaller cc-pVDZ basis set and the experimental photoelectron spectrum measured at a photon energy of 80 eV on the PLÉIADES beamline at the Soleil synchrotron radiation source allowed all the main features to be assigned. Some theoretical aspects of the ionization energy calculations concerning the use of various approximation schemes and basis sets are discussed.

  2. Quantitative Mobility Spectrum Analysis for Determination of Electron and Magneto Transport Properties of Te-Doped GaSb

    Institute of Scientific and Technical Information of China (English)

    S. Acar; M. Kasap; B. Y. Isik; S.(O)zcelik; N. Tugluoglu; S. Karadeniz

    2005-01-01

    @@ Resistivity, magnetoresistivity and Hall effect measurements in n-type Te-doped GaSb grown by the liquid encapsuled Czochralski technique are carried out as functions of temperature (35-350 K) and magnetic field (0-1.35 T).The power law model is used to explain the temperature-dependent resistivity. The magnetic-field-dependent data are analysed using the quantitative mobility spectrum analysis technique. The effect of individual band parameters (nL, nг, μL, μг, p and μp) on both the electron and magneto transports have been discussed. The EL -- Eг energy separation between the L and conduction band edges is also derived.

  3. The Electronic Spectrum of Gaseous CoO in the Visible Region

    Science.gov (United States)

    Barnes; Clouthier; Hajigeorgiou; Huang; Kingston; Merer; Metha; Peers; Rixon

    1997-12-01

    Laser excitation spectra of gaseous CoO have been recorded using Doppler-limited intracavity spectroscopy and supersonic jet-cooled molecular beam methods. As seen in the molecular beam spectra there are nearly 100 bands arising from the X4Delta7/2 spin component of the ground state in the wavelength region 430-720 nm. All of them are very strongly red-degraded and most of them are perturbed. 59Co hyperfine broadenings or splittings have been observed in many. The bands can be arranged into five electronic transitions, together with a considerable number of "extra" bands induced by perturbations; two of the excited electronic states are 4Phi, while the other three, which lie within 1700 cm-1, are 4Delta. Semi-empirical calculations have been carried out for the 4Delta excited states, using exchange integrals transferred from the TiO and VO spectra; the predicted energies, spin-orbit structures, and relative intensities in absorption are consistent with the assignment of all three 4Delta states to the same electron configuration, (4ssigma)1(3ddelta)3(3dpi)2(3dsigma)1. It seems that there are extensive interactions between the excited 4Delta states, because only one of them gives rise to a recognizable, though irregular, long vibrational progression in absorption. The other two progressions die out abruptly and unexpectedly after three or four members, presumably as a result of interference effects; however, wavelength-resolved fluorescence studies, together with calculations of the Franck-Condon overlap integrals to the various vibrational levels of the ground state, show that the upper state progressions reappear following a region of confused absorption. All of the excited states show highly irregular variations of their vibrational intervals and rotational constants with the vibrational quantum number, v. The wavelength-resolved fluorescence spectra give evidence for new low-lying electronic states of CoO at 3038, 5989, and 9105 cm-1; based on its vibrational

  4. The role of electron-emitting radiopharmaceuticals in the palliative treatment of metastatic bone pain and for radiosynovectomy: applications of conversion electron emitter Tin-117m

    Directory of Open Access Journals (Sweden)

    Suresh C. Srivastava

    2007-09-01

    Full Text Available A variety of radionuclides continue to be investigated and/or clinically used for different therapeutic applications in nuclear medicine. The choice of a particular radionuclide with regard to appropriate emissions, linear energy transfer (LET, and physical half-life, etc., is dictated to a large extent by the character of the disease (e.g., solid tumor or metastatic disease, and by the carrier to selectively transport the radionuclide to the desired site. An impressive body of information has appeared in the recent literature that addresses many of these considerations. This article summarizes and discusses the role of high-LET electron emitters and their advantage in the treatment of cancer or for other disorders in specific situations. Areas such as bone pain palliation, bone malignancy therapy, and radiation synovectomy are covered in greater detail. Projections are made as to the future directions and progress in these areas. A discussion of the various issues related to the selection criteria that are useful for choosing the appropriate radionuclide for a particular application is included. Use of high-LET electron emitters is discussed in greater detail, with particular emphasis on the use of conversion electron emitter tin-117m for various therapeutic applications.Uma variedade de radionuclídeos continua a ser investigada e/ou clinicamente utilizada para diferentes aplicações terapêuticas em medicina nuclear. A escolha de um radionuclídeo, considerando-se sua emissão apropriada, transferência linear de energia (LET e meia-vida física é determinada na maior parte pelo caráter da doença (p.ex., tumor sólido ou doença metastática, e pelo carreador que transporta o radionuclídeo seletivamente para o sítio desejado. Um notável conjunto de informações voltadas para essas considerações tem aparecido na literatura recente. Esse trabalho resume e discute o papel de emissores de elétrons de alta-LET e sua vantagem no

  5. Impulsive solar X-ray bursts. III - Polarization, directivity, and spectrum of the reflected and total bremsstrahlung radiation from a beam of electrons directed toward the photosphere

    Science.gov (United States)

    Langer, S. H.; Petrosian, V.

    1977-01-01

    The paper presents the spectrum, directivity, and state of polarization of the bremsstrahlung radiation expected from a beam of high-energy electrons spiraling along radial magnetic field lines toward the photosphere. A Monte Carlo method is then described for evaluation of the spectrum, directivity, and polarization of X-rays diffusely reflected from stellar photospheres. The accuracy of the technique is evaluated through comparison with analytic results. The calculated characteristics of the incident X-rays are used to evaluate the spectrum, directivity, and polarization of the reflected and total X-ray fluxes. The results are compared with observations.

  6. The Conversion and operation of the Cornell electron storage ring as a test accelerator (cesrta) for damping rings research and development

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, M.A.; Alexander, J.; Byrd, J.; Celata, C.M.; Corlett, J.; De Santis, S.; Furman, M.; Jackson, A.; Kraft, R.; Munson, D.; Penn, G.; Plate, D.; Rawlins, A.; Venturini, M.; Zisman, M.; Billing, M.; Calvey, J.; Chapman, S.; Codner, G.; Conolly, C.; Crittenden, J.; Dobbins, J.; Dugan, G.; Fontes, E.; Forster, M.; Gallagher, R.; Gray, S.; Greenwald, S.; Hartill, D.; Hopkins, W.; Kandaswamy, J.; Kreinick, D.; Li, Y.; Liu, X.; Livezey, J.; Lyndaker, A.; Medjidzade, V.; Meller, R.; Peck, S.; Peterson, D.; Rendina, M.; Revesz, P.; Rice, D.; Rider, N.; Rubin, D.; Sagan, D.; Savino, J.; Seeley, R.; Sexton, J.; Shanks, J.; Sikora, J.; Smolenski, K.; Strohman, C.; Temnykh, A.; tigner, M.; Whitney, W.; Williams, H.; Vishniakou, S.; Wilkens, T.; Harkay, K.; Holtzapple, R.; Smith, E.; Jones, J.; Wolski, A.; He, Y.; Ross, M.; Tan, C.Y.; Zwaska, R.; Flanagan, J.; Jain, P.; Kanazawa, K.; Ohmi, K.; Sakai, H.; Shibata, K.; Suetsugu, Y.; Kharakh, D.; Pivi, M.; Wang, L.

    2009-05-01

    In March of 2008, the Cornell Electron Storage Ring (CESR) concluded twenty eight years of colliding beam operations for the CLEO high energy physics experiment. We have reconfigured CESR as an ultra low emittance damping ring for use as a test accelerator (CesrTA) for International Linear Collider (ILC) damping ring R&D. The primary goals of the CesrTA program are to achieve a beam emittance approaching that of the ILC Damping Rings with a positron beam, to investigate the interaction of the electron cloud with both low emittance positron and electron beams, to explore methods to suppress the electron cloud, and to develop suitable advanced instrumentation required for these experimental studies (in particular a fast x-ray beam size monitor capable of single pass measurements of individual bunches). We report on progress with the CESR conversion activities, the status and schedule for the experimental program, and the first experimental results that have been obtained.

  7. Multiconfigurational second-order perturbation calculation of the electronic absorption spectrum of trisilane, Si 3 H 8

    Science.gov (United States)

    Piqueras, Mari Carmen; Crespo, Raül; Michl, Josef

    The low-lying singlet excited states of trisilane have been computed using the complete active space self-consistent field (CASSCF) method, second-order perturbation theory (CASPT2), and the extended multistate CASPT2 (MS-CASPT2) approach, and a generally contracted basis set of atomic natural orbitals (ANOs) including Rydberg functions. The ground state structure was obtained from an ab initio optimization at the second-order Møller-Plesset perturbation theory (MP2) level using Dunning's correlation-consistent triple-zeta basis set (cc-pVTZ) and agrees well with experiment. The calculation of the electronic transitions included the lower valence excited states and two Rydberg series converging to the first two ionization potentials. Only the MS-CASPT2 method gave an accurate description of the observed electronic excitations since it provided an effective separation of the valence and Rydberg states. In contrast with previous assignments, three states of valence character were found below the first Rydberg state, located at 7.20 eV. As a consequence, the first broad band observed in the spectrum is entirely of valence character. Vertical dipole-allowed valence transition energies are calculated at 6.55, 7.09, 7.32, 7.60, 8.07 and 8.18 eV (excitations to 11B2, 21A1, 31A1, 11B1, 51B2 and 21B1 states, respectively). Two vertical dipole-forbidden valence transitions assigned to the 11A2 and 41A2 states are found at 6.89 and 8.52 eV, respectively. The 4s, 4p and 3d members of the Rydberg series converging to the first and second ionization potentials are found at 7.20-8.62 eV and 7.82-9.61 eV, respectively. A detailed theoretical interpretation of the absorption spectrum of trisilane based on the new assignments has been proposed, and comments on the ability of the CASSCF, CASPT2 and MS-CASPT2 approaches to describe accurately the absorption spectrum of oligosilanes are made.

  8. Density Fluctuation Spectrum of Solar Wind Turbulence between Ion and Electron Scales

    CERN Document Server

    Chen, C H K; Bonnell, J W; Mozer, F S; Bale, S D

    2012-01-01

    We present a measurement of the spectral index of density fluctuations between ion and electron scales in solar wind turbulence using the EFI instrument on the ARTEMIS spacecraft. The mean spectral index at 1 AU was found to be -2.75 +/- 0.06, steeper than predictions for pure whistler or kinetic Alfven wave turbulence, but consistent with previous magnetic field measurements. The steep spectra are also consistent with expectations of increased intermittency or damping of some of the turbulent energy over this range of scales. Neither the spectral index nor the flattening of the density spectra before ion scales were found to depend on the proximity to the pressure anisotropy instability thresholds, suggesting that they are features inherent to the turbulent cascade.

  9. Engagement with electronic screen media among students with autism spectrum disorders.

    Science.gov (United States)

    Mineo, Beth A; Ziegler, William; Gill, Susan; Salkin, Donna

    2009-01-01

    This study investigated the relative engagement potential of four types of electronic screen media (ESM): animated video, video of self, video of a familiar person engaged with an immersive virtual reality (VR) game, and immersion of self in the VR game. Forty-two students with autism, varying in age and expressive communication ability, were randomly assigned to the experimental conditions. Gaze duration and vocalization served as dependent measures of engagement. The results reveal differential responding across ESM, with some variation related to the engagement metric employed. Preferences for seeing themselves on the screen, as well as for viewing the VR scenarios, emerged from the data. While the study did not yield definitive data about the relative engagement potential of ESM alternatives, it does provide a foundation for future research, including guidance related to participant profiles, stimulus characteristics, and data coding challenges.

  10. Spectrum-splitting approach for Fermi-operator expansion in all-electron Kohn-Sham DFT calculations

    CERN Document Server

    Motamarri, Phani; Bhattacharya, Kaushik; Ortiz, Michael

    2016-01-01

    We present a spectrum-splitting approach to conduct all-electron Kohn-Sham density functional theory (DFT) calculations by employing Fermi-operator expansion of the Kohn-Sham Hamiltonian. The proposed approach splits the subspace containing the occupied eigenspace into a core-subspace, spanned by the core eigenfunctions, and its complement, the valence-subspace, and thereby enables an efficient computation of the Fermi-operator expansion by reducing the expansion to the valence-subspace projected Kohn-Sham Hamiltonian. The key ideas used in our approach are: (i) employ Chebyshev filtering to compute a subspace containing the occupied states followed by a localization procedure to generate non-orthogonal localized functions spanning the Chebyshev-filtered subspace; (ii) compute the Kohn-Sham Hamiltonian projected onto the valence-subspace; (iii) employ Fermi-operator expansion in terms of the valence-subspace projected Hamiltonian to compute the density matrix, electron-density and band energy. We demonstrate ...

  11. Direct 1{sup +}{yields}N{sup +} conversion of stable alkali ions using an electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Mery, A.; Jardin, P.; Saint-Laurent, M. G.; Bajeat, O.; Delahaye, P.; Dubois, M.; Fraanberg-Delahaye, H.; Lecomte, P.; Leherissier, P.; Maunoury, L.; Pichard, A.; Pacquet, J. Y.; Thomas, J. C. [GANIL, Bd Henri Becquerel, BP 55027, 14076 CAEN Cedex 5 (France); Alcantara-Nunez, J. [Departamento de Fisica de Particulas, Universidad Santiago de Compostela, 15782 Santiago de Compostela (Spain)

    2010-02-15

    The production of radioactive ions using the Isotope Separation On-Line method gives rise, in most cases, to singly charged ions. In order to perform experiments with postaccelerated radioactive ion beams, these ions have to be multicharged. We describe here a new compact design for a charge breeder that will be coupled to the production target of SPIRAL1 at GANIL. We present recent results obtained offline with stable alkali ions (Na, K, Rb, and Cs) on the SIRa test bench. Particularly, 1{sup +} to N{sup +} conversion efficiencies and conversion times are presented. Several points have been identified for the improvements of the present performances.

  12. Electron Bernstein wave heating and emission measurement through the very narrow O-X-B mode conversion window in the LHD

    Energy Technology Data Exchange (ETDEWEB)

    Igami, H.; Shimozuma, T.; Yoshimura, Y.; Takahashi, H.; Nishiura, M.; Seki, T.; Osakabe, M.; Mutoh, T. [National Institute for Fusion Science, Toki (Japan); Kubo, S. [National Institute for Fusion Science, Toki, Japan and Department of Energy Engineering and Science, Nagoya Univ., Nagoya (Japan); Ogasawara, S.; Makino, R. [Department of Energy Engineering and Science, Nagoya Univ., Nagoya (Japan); Idei, H. [Research Institute for Applied Mechanics, Kyusyu Univ., Kasuga (Japan); Nagasaki, K. [Institute of Advanced Energy, Kyoto Univ., Uji (Japan)

    2014-02-12

    In the large helical device (LHD), the theoretically predicted width of the ordinary-extraordinary-electron Bernstein wave (O-X-B) mode conversion (MC) window is comparable to the beam width and the power deposition is located in the off-axis region if the 77GHz fundamental electron cyclotron (EC) wave of is launched from an existing horizontal port antenna. In the experiment, the actual MC window location was looked for with changing the aiming. The effective aiming with that the increase of the stored energy was observed was two degrees apart from the location of the theoretical MC window at a maximum. Measurement of the waves originated from the thermally emitted EBW and radiated via the B-X-O mode conversion process is effective to improve the accuracy of the theoretical prediction with comparison between the theoretical and the experimental results. The theoretical prediction suggests that the width of the MC window of the fundamental 77GHz EC wave can be expanded if the lower port antenna is used. On the other hand, the MC window of the second harmonic 154GHz EC wave is blocked by horizontal port wall if another horizontal port antenna is used. It is required to move the final mirror of the quasi-optical antenna toward the plasma surface. Focusing of the beam at the plasma cutoff is (PC) also necessary for the effective mode conversion.

  13. The excitation energy spectrum for a system with electron pairs tunneling in a two-leg ladder has a doping depended gap

    CERN Document Server

    Voroshilov, Valentin

    2016-01-01

    A new model with a new Hamiltonian and a new canonical transformation is offered as the means for studying properties of a system of strongly correlated electrons. Consideration of the simplest possible situation, namely a system on non-interacting electrons in a two-leg ladder, leads to an expression for the excitation energy spectrum with no energy gap at the half-filling and with an energy gap away from the half filling.

  14. Solid-state dye-sensitized mesoporous TiO{sub 2} solar cells with high photon-to-electron conversion efficiencies

    Energy Technology Data Exchange (ETDEWEB)

    Bach, U.; Comte, P.; Moser, J.E.; Gratzel, M. [Swiss Federal Institute of Technology, Laussanne (Switzerland). Inst. of Photonics and Interfaces; Lupo, D.; Spreitzer, H. [Hoechst Research and Technology Deutschland GmbH and Co., Frankfurt (Germany); Weissortel, F.; Salbeck, J. [Max-Planck-Institute fuer Polymerforschung, Mainz (Germany)

    1998-10-08

    Solar cells based on dye-sensitized mesoporous films of TiO{sub 2} are low-cost alternatives to conventional solid-state devices. Impressive solar-to-electrical energy conversion efficiencies have been achieved with such films when used in conjunction with liquid electrolytes. Practical advantages may be gained by the replacement of the liquid electrolyte with a solid charge-transport material. Inorganic p-type semiconductors and organic materials have been tested in this regard, but in all cases the incident monochromatic photon-to-electron conversion efficiency remained low. Here we describe a dye-sensitized heterojunction of TiO{sub 2} with the amorphous organic hole-transport material 2,2`,7,7`-tetrakis (N,N-di-p-methoxyphenyl-amine) 9,9`-spirobifluorene. (author)

  15. Unmixing of Rock Thermal Infrared Spectrum and Conversion of Mineral Content%岩石热红外光谱解混与矿物含量反演

    Institute of Scientific and Technical Information of China (English)

    刘善军; 卓建英; 吴立新; 徐忠印

    2011-01-01

    Distinguishing and converting mineral ingredient and content based on the spectrum unmixing of rock are an important direction of high-spectral remote sensing. The thermal infrared spectrum of a block of alkali feldspar granite is measured by using Turbo FT portable infrared spectral radiometer in outdoor site and normal temperature, and the thermal infrared spectrums (7-14u,m) of four mineral ingredients of the rock, that is, potash feldspar, plagioclase, white mica, and quartz are also measured under three different conditions, I.e. Grain sample of 0.71-lmm in outdoor site and normal temperature, grain sample of 0.71-lmm in indoor site and 80t, and block sample at outdoor site and normal temperature. Then the spectrum of the rock is linearly decomposed by using the spectrums of the four minerals as the end members, and the results are compared with the results that the ASU spectrum is used as the end member. The result shows that the unmixing effect is best when the spectrums of rock and the end member mineral are measured in the same condition; and that the spectrum of block rock could be decomposed by the spectrums of block minerals, however it could not be decomposed by ASU spectrum. The experimental result is beneficial to the remote sensing geology and mineral mapping.%以碱性长石花岗岩为例,采用Turbo FT便携式红外光谱辐射计对其4种组成矿物(钾长石、斜长石、白云母、石英)分别进行0.71—1mm颗粒室外常温、0.71—1mm颗粒室内80℃、块体室外常温的热红外(7—14μm)光谱特征测试,以测试结果作为端元光谱对室外常温下测得的块状碱性长石花岗岩光谱进行解混,并与将ASU光谱作为端元光谱的解混效果进行比较.结果表明,当岩石与矿物端元的光谱测试条件相同时,解混效果最好;使用块状端元光谱能有效解混块状岩石光谱;ASU颗粒光谱不能解混块体岩石的矿物成分及含量.试验结果对遥感地质及矿物填图的研究具有指导意义.

  16. Photovoltaic conversion of visible spectrum by GaP capped InP quantum dots grown on Si (100) by metalorganic chemical vapor deposition

    Science.gov (United States)

    Halder, Nripendra N.; Biswas, Pranab; Banerji, P.; Kundu, Souvik; Nagabhushan, B.; Sarkar, Krishnendu; Chowdhury, Sisir; Chaudhuri, Arunava

    2015-01-01

    Growth of GaP capped strained InP quantum dots was carried out by metal organic chemical vapor deposition technique on Si (100) substrates to explore an alternative material system for photovoltaic conversion. Studies on reflectance spectroscopy show higher absorption of visible photons compared to scattering. Smooth and defect free interface provides low dark current with high rectification ratio. A solar cell made of five periods of quantum dots is found to provide a conversion efficiency of 4.18% with an open circuit voltage and short circuit current density of 0.52 V and 13.64 mA/cm2, respectively, under AM 1.5 solar radiation.

  17. Effects of supported electronic text and explicit instruction on science comprehension by students with autism spectrum disorder

    Science.gov (United States)

    Knight, Victoria Floyd

    Supported electronic text (eText), or text that has been altered to increase access and provide support to learners, may promote comprehension of science content for students with disabilities. According to CAST, Book Builder(TM) uses supported eText to promote reading for meaning for all students. Although little research has been conducted in the area of supported eText for students with autism spectrum disorders (ASD), technology (e.g., computer assisted instruction) has been used for over 35 years to instruct students with ASD in academic areas. The purpose of this study was to evaluate the effects of a supported eText and explicit instruction on the science vocabulary and comprehension of four middle school students with ASD. Researchers used a multiple probe across participants design to evaluate the Book Builder (TM) program on measures of vocabulary, literal comprehension, and application questions. Results indicated a functional relation between the Book Builder(TM) and explicit instruction (i.e., model-lead-test, examples and non-examples, and referral to the definition) and the number of correct responses on the probe. In addition, students were able to generalize concepts to untrained exemplars. Finally, teachers and students validate the program as practical and useful.

  18. The development of a new edition of the gamma-ray spectrum catalogues designed for presentation in electronic format

    Energy Technology Data Exchange (ETDEWEB)

    Heath, R.L. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1997-11-01

    New editions of the original Gamma-ray Spectrum Catalogues are being prepared for publication in electronic format. The objective of this program is to produce versions of the Catalogues in CD-ROM format and as an Internet resource. Additions to the original content of the Catalogues will include integrated decay scheme drawings, tables of related decay data, and updated text on the techniques of gamma-ray spectrometry. Related decay data from the Evaluated Nuclear Structure Data File (ENSDF) are then added, and all data converted to the Adobe Acrobat (PDF) format for CD-ROM production and availability on the large-volume Ge detectors, alpha-particle spectra, prompt neutron capture and inelastic scattering gamma-ray spectra, and gross fission product spectra characteristic of fuel cycle waste materials. Characterization of radioactivity in materials is a requirement in many phases of radioactive waste management. Movement, shipping, treatment, all activities which involve handling of mixed waste or TRU categories of waste at all DOE sites will require that measurements and assessment documentation utilize basic nuclear data which are tracable to internationally accepted standard values. This program will involve the identification of data needs unique to the development and application of specialized detector systems for radioactive waste characterization. 8 refs., 8 figs.

  19. Photoelectron spectrum of valence anions of uracil and first-principles calculations of excess electron binding energies

    Science.gov (United States)

    Bachorz, Rafał A.; Klopper, Wim; Gutowski, Maciej; Li, Xiang; Bowen, Kit H.

    2008-08-01

    The photoelectron spectrum (PES) of the uracil anion is reported and discussed from the perspective of quantum chemical calculations of the vertical detachment energies (VDEs) of the anions of various tautomers of uracil. The PES peak maximum is found at an electron binding energy of 2.4 eV, and the width of the main feature suggests that the parent anions are in a valence rather than a dipole-bound state. The canonical tautomer as well as four tautomers that result from proton transfer from an NH group to a C atom were investigated computationally. At the Hartree-Fock and second-order Møller-Plesset perturbation theory levels, the adiabatic electron affinity (AEA) and the VDE have been converged to the limit of a complete basis set to within +/-1 meV. Post-MP2 electron-correlation effects have been determined at the coupled-cluster level of theory including single, double, and noniterative triple excitations. The quantum chemical calculations suggest that the most stable valence anion of uracil is the anion of a tautomer that results from a proton transfer from N1H to C5. It is characterized by an AEA of 135 meV and a VDE of 1.38 eV. The peak maximum is as much as 1 eV larger, however, and the photoelectron intensity is only very weak at 1.38 eV. The PES does not lend support either to the valence anion of the canonical tautomer, which is the second most stable anion, and whose VDE is computed at about 0.60 eV. Agreement between the peak maximum and the computed VDE is only found for the third most stable tautomer, which shows an AEA of ~-0.1 eV and a VDE of 2.58 eV. This tautomer results from a proton transfer from N3H to C5. The results illustrate that the characteristics of biomolecular anions are highly dependent on their tautomeric form. If indeed the third most stable anion is observed in the experiment, then it remains an open question why and how this species is formed under the given conditions.

  20. Tuning the near-gap electronic structure of Cu2O by anion-cation co-doping for enhanced solar energy conversion

    Science.gov (United States)

    Si, Yuan; Yang, Hao-Ming; Wu, Hong-Yu; Huang, Wei-Qing; Yang, Ke; Peng, Ping; Huang, Gui-Fang

    2017-01-01

    Doping is an effective strategy to tune the electronic properties of semiconductors, but some side effects caused by mono-doping degrade the specific performance of matrixes. As a model system to minimize photoproduced electron-hole pairs recombination by anion-cation co-doping, we investigate the electronic structures and optical properties of (Fe+N) co-doped Cu2O using the first-principles calculations. Compared to the case of mono-doping, the FeCuNO (a Fe (N) atom substituting a Cu (O) atom) co-doping reduces the energy cost of doping as a consequence of the charge compensation between the iron and nitrogen impurities, which eliminates the isolated levels (induced by mono-dopant) in the band gap. Interestingly, it is found that the contributions of different host atoms (Cu and O) away from anion (N) and cation (Fe) dopants to the variation of near band gap electronic structure of the co-doped Cu2O are different. Moreover, co-doping reduces the band gap and increases the visible-light absorption of Cu2O. Both band gap reduction and low recombination rate are critical elements for efficient light-to-current conversion in co-doped semiconductor photocatalysts. These findings raise the prospect of using co-doped Cu2O with specifically engineered electronic properties in a variety of solar applications.

  1. B factory via conversion of 1 TeV electron beams into 1 TeV photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Mtingwa, S.K.; Strikman, M.

    1989-01-01

    We derive formulae which describe the interaction of laser beams with electron beams. Specializing to the case of 1 TeV electron beams from the future generation of electron linear accelerators, we calculate the production rate of backscattered 1 TeV photons, and using these photons, we show that it is possible to organize the photoproduction of beauty particles so as to measure 10/sup 9/b/bar b/ pairs per year. This should be adequate to study rare decays and CP violation in B meson decay. 9 refs., 1 fig.

  2. Electronic spectrum of non-tetrahedral acceptors in CdTe:Cl and CdTe:Bi,Cl single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Krivobok, V. S., E-mail: krivobok@lebedev.ru [P.N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow (Russian Federation); Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Region (Russian Federation); Nikolaev, S. N.; Bagaev, V. S.; Pruchkina, A. A.; Onishchenko, E. E.; Kolosov, S. A.; Klevkov, Yu. V.; Skorikov, M. L. [P.N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2016-02-07

    The electronic spectra of complex acceptors in compensated CdTe:Cl, CdTe:Ag,Cl, and CdTe:Bi,Cl single crystals are studied using low-temperature photoluminescence (PL) measurements under both nonresonant and resonant excitation of distant donor–acceptor pairs (DAP). The wavelength modulation of the excitation source combined with the analysis of the differential PL signal is used to enhance narrow spectral features obscured because of inhomogeneous line broadening and/or excitation transfer for selectively excited DAPs. For the well-known tetrahedral (T{sub D}) Ag{sub Cd} acceptor, the energies of four excited states are measured, and the values obtained are shown to be in perfect agreement with the previous data. Moreover, splitting between the 2P{sub 3/2} (Γ{sub 8}) and 2S{sub 3/2} (Γ{sub 8}) states is clearly observed for Ag{sub Cd} centers located at a short distance (5–7 nm) from a hydrogen-like donor (Cl{sub Te}). This splitting results from the reduction of the T{sub D} symmetry taking place when the acceptor is a member of a donor–acceptor pair. For the Cl-related complex acceptor with an activation energy of ∼121 meV (A-center), the energies of eight excited states are measured. It is shown that this defect produces low-symmetry central-cell correction responsible for the strong splitting of S-like T{sub D} shells. The energy spectrum of the Bi-related shallow acceptor with an activation energy of ∼36 meV is measured as well. The spectrum obtained differs drastically from the hydrogen-like set of levels, which indicates the existence of repulsive low-symmetry perturbation of the hydrogen-like Coulomb potential. It is also shown that the spectra of selectively excited PL recorded for a macroscopic ensemble of distant donor–acceptor pairs allow one to detect the low symmetry of acceptors of a given type caused by their complex nature or by the Jahn–Teller distortion. This method does not require any additional (external) field and is

  3. Computational characterization of competing energy and electron transfer states in bimetallic donor-acceptor systems for photocatalytic conversion

    Science.gov (United States)

    Fredin, Lisa A.; Persson, Petter

    2016-09-01

    The rapidly growing interest in photocatalytic systems for direct solar fuel production such as hydrogen generation from water splitting is grounded in the unique opportunity to achieve charge separation in molecular systems provided by electron transfer processes. In general, both photoinduced and catalytic processes involve complicated dynamics that depend on both structural and electronic effects. Here the excited state landscape of metal centered light harvester-catalyst pairs is explored using density functional theory calculations. In weakly bound systems, the interplay between structural and electronic factors involved can be constructed from the various mononuclear relaxed excited states. For this study, supramolecular states of electron transfer and excitation energy transfer character have been constructed from constituent full optimizations of multiple charge/spin states for a set of three Ru-based light harvesters and nine transition metal catalysts (based on Ru, Rh, Re, Pd, and Co) in terms of energy, structure, and electronic properties. The complete set of combined charge-spin states for each donor-acceptor system provides information about the competition of excited state energy transfer states with the catalytically active electron transfer states, enabling the identification of the most promising candidates for photocatalytic applications from this perspective.

  4. Computational characterization of competing energy and electron transfer states in bimetallic donor-acceptor systems for photocatalytic conversion.

    Science.gov (United States)

    Fredin, Lisa A; Persson, Petter

    2016-09-14

    The rapidly growing interest in photocatalytic systems for direct solar fuel production such as hydrogen generation from water splitting is grounded in the unique opportunity to achieve charge separation in molecular systems provided by electron transfer processes. In general, both photoinduced and catalytic processes involve complicated dynamics that depend on both structural and electronic effects. Here the excited state landscape of metal centered light harvester-catalyst pairs is explored using density functional theory calculations. In weakly bound systems, the interplay between structural and electronic factors involved can be constructed from the various mononuclear relaxed excited states. For this study, supramolecular states of electron transfer and excitation energy transfer character have been constructed from constituent full optimizations of multiple charge/spin states for a set of three Ru-based light harvesters and nine transition metal catalysts (based on Ru, Rh, Re, Pd, and Co) in terms of energy, structure, and electronic properties. The complete set of combined charge-spin states for each donor-acceptor system provides information about the competition of excited state energy transfer states with the catalytically active electron transfer states, enabling the identification of the most promising candidates for photocatalytic applications from this perspective.

  5. Electronic spectrum and photodissociation chemistry of the linear methyl propargyl cation H2C4H3+

    Science.gov (United States)

    Catani, Katherine J.; Muller, Giel; da Silva, Gabriel; Bieske, Evan J.

    2017-01-01

    The electronic spectrum of the methyl propargyl cation (2-butyn-1-yl cation, H2C4H3+) is measured over the 230-270 nm range by photodissociating the bare cation and its Ar and N2 tagged complexes in a tandem mass spectrometer. The observed '1A←'1A band system has an origin at 37 753 cm-1 for H2C4H3+ , 37738 cm-1 for H2C4H3+ - Ar, and 37 658 cm-1 for H2C4H3+ - N2. The methyl propargyl cation photodissociates to produce either C2H3++C2H2 (protonated acetylene + acetylene) or H2C4H+ +H2 (protonated diacetylene + dihydrogen). Photodissociation spectra of H2C4H3+ , H2C4H3+ - Ar, and H2C4H3+ - N2 exhibit similar vibronic structure, with a strong progression of spacing 630 cm-1 corresponding to excitation of the C—C stretch mode. Interpretation of the spectra is aided by ground and excited state calculations using time dependent density functional theory at the ωB97X-D/aug-cc-pVDZ level of theory. Ab initio calculations and master equation simulations were used to interpret the dissociation of H2C4H3+ on the ground state manifold. These calculations support the experimentally observed product branching ratios in which acetylene elimination dominates and also suggests that channel switching occurs at higher energies to favor H2 elimination.

  6. Conversational Dominance.

    Science.gov (United States)

    Esau, Helmut; Poth, Annette

    Details of conversational behavior can often not be interpreted until the social interaction, including the rights and obligations of the participants, their intent, the topic, etc., has been defined. This paper presents a model of conversation in which the conversational image a person presents in a given conversational situation is a function of…

  7. Nonoxido V(IV) Complexes: Prediction of the EPR Spectrum and Electronic Structure of Simple Coordination Compounds and Amavadin.

    Science.gov (United States)

    Sanna, Daniele; Sciortino, Giuseppe; Ugone, Valeria; Micera, Giovanni; Garribba, Eugenio

    2016-08-01

    Density functional theory (DFT) calculations of the (51)V hyperfine coupling (HFC) tensor A have been completed for 20 "bare" V(IV) complexes with different donor sets, electric charges, and coordination geometries. Calculations were performed with ORCA and Gaussian software, using functionals BP86, TPSS0, B1LYP, PBE0, B3LYP, B3P, B3PW, O3LYP, BHandHLYP, BHandH, and B2PLYP. Among the basis sets, 6-311g(d,p), 6-311++g(d,p), VTZ, cc-pVTZ, def2-TZVPP, and the "core properties" CP(PPP) were tested. The experimental Aiso and Ai (where i = x or z, depending on the geometry and electronic structure of V(IV) complex) were compared with the values calculated by DFT methods. The results indicated that, based on the mean absolute percentage deviation (MAPD), the best functional to predict Aiso or Ai is the double hybrid B2PLYP. With this functional and the basis set VTZ, it is possible to predict the Aiso and Az of the EPR spectrum of amavadin with deviations of -1.1% and -2.0% from the experimental values. The results allowed us to divide the spectra of nonoxido V(IV) compounds in three types-called "type 1", "type 2", and "type 3", characterized by different composition of the singly occupied molecular orbital (SOMO) and relationship between the values of Ax, Ay, and Az. For "type 1" spectra, Az ≫ Ax ≈ Ay and Az is in the range of (135-155) × 10(-4) cm(-1); for "type 2" spectra, Ax ≈ Ay ≫ Az and Ax ≈ Ay are in the range of (90-120) × 10(-4) cm(-1); and for the intermediate spectra of "type 3", Az > Ay > Ax or Ax > Ay > Az, with Az or Ax values in the range of (120-135) × 10(-4) cm(-1). The electronic structure of the V(IV) species was also discussed, and the results showed that the values of Ax or Az are correlated with the percent contribution of V-dxy orbital in the SOMO. Similarly to V(IV)O species, for amavadin the SOMO is based mainly on the V-dxy orbital, and this accounts for the large experimental value of Az (153 × 10(-4) cm(-1)).

  8. A Galactic Cosmic Ray Electron Spectrum from 2 MeV to 2 TeV That Fits Voyager 5-60 MeV Data at Low Energies and PAMELA and AMS-2 Data at 10 GeV Using an Electron Source Spectrum E^-2.25 A Calculation Using a Monte Carlo Diffusion Model

    CERN Document Server

    Webber, W R

    2015-01-01

    In this paper we fit the observed galactic cosmic ray electron spectrum from a few MeV to 1 TeV. New data from Voyager from 5-60 MeV beyond the heliopause is used along with high energy data from the PAMELA, FERMI and AMS-2 instruments in Earth orbit. Using a Monte Carlo diffusion model for galactic propagation we obtain a source rigidity spectrum with a spectral index =-2.25 independent of energy below 10 GeV, possibly steepening above 10 GeV to 2.40 at the highest energies. This spectrum will fit the electron data over 5 orders of magnitude to within + 10% at both low and high energies. This steepening of the electron source spectrum could be an important feature of the acceleration process, e.g., synchrotron loss during acceleration could steepen the source spectrum. This fit requires only a single break in the rigidity dependence of the diffusion coefficient by ~1.0 power in the exponent at about 1.0 GV. The calculations also predict the distribution of electrons perpendicular to the galactic disk. The ga...

  9. Computation of the spectrum of spatial Lyapunov exponents for the spatially extended beam-plasma systems and electron-wave devices

    CERN Document Server

    Hramov, Alexander E; Maximenko, Vladimir A; Moskalenko, Olga I; 10.1063/1.4740063

    2013-01-01

    The spectrum of Lyapunov exponents is powerful tool for the analysis of the complex system dynamics. In the general framework of nonlinear dynamical systems a number of the numerical technics have been developed to obtain the spectrum of Lyapunov exponents for the complex temporal behavior of the systems with a few degree of freedom. Unfortunately, these methods can not apply directly to analysis of complex spatio-temporal dynamics in plasma devices which are characterized by the infinite phase space, since they are the spatially extended active media. In the present paper we propose the method for the calculation of the spectrum of the spatial Lyapunov exponents (SLEs) for the spatially extended beam-plasma systems. The calculation technique is applied to the analysis of chaotic spatio-temporal oscillations in three different beam-plasma model: (1) simple plasma Pierce diode, (2) coupled Pierce diodes, and (3) electron-wave system with backward electromagnetic wave. We find an excellent agreement between the...

  10. Visible part of the multiline electronic-vibro-rotational emission spectrum of the $D_2$ molecule measured with moderate resolution. I. Experimental technique and data processing

    CERN Document Server

    Lavrov, B P

    2013-01-01

    The visible part ($\\approx 419 \\div 696$ nm) of the multiline electronic-vibro-rotational emission spectrum of the $D_2$ molecule was recorded with moderate resolution mainly limited by Doppler broadening of spectral lines (line widths $FWHM \\approx 0.013$ nm). After numerical deconvolution of the recorded intensity distributions and proper calibration of the spectrometer the new set of wavenumber values was obtained.

  11. Effect of magnetic field on energy spectrum and localization of electron in CdS/HgS/CdS/HgS/CdS multilayered spherical nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Holovatsky, V.A., E-mail: ktf@chnu.edu.ua; Bernik, I.B.; Yakhnevych, M. Ya.

    2017-03-01

    The theoretical investigation of magnetic field effect on energy spectrum and localization of the electron and oscillator strengths of intraband quantum transitions in the nanostructure CdS/HgS/CdS/HgS/CdS is performed. The calculations are made in the framework of effective mass approximation and rectangular potential barriers model using the method of the expansion of quasi-particle wave functions over the complete basis of functions obtained as the exact solutions of the Schrodinger equation for the electron in the nanostructure without the magnetic field. It is shown that the magnetic field violates the spherical symmetry of the system and takes off the degeneration of energy spectrum with respect to the magnetic quantum number. The energy of the electron in the states with m≥0 increases when magnetic field enhances; for the states with m<0 these dependences are non-monotonous (decreasing at first and then increasing). Moreover, the ground state of electron is formed alternately by the states with m=0, −1, −2, …. Magnetic field influences on the distribution of quasi-particle density. It is shown that the electron significantly changes its localization in the nanostructure with two potential wells tunneling through the potential barrier under the effect of magnetic field, changing the oscillator strengths of intraband quantum transitions.

  12. Effect of magnetic field on energy spectrum and localization of electron in CdS/HgS/CdS/HgS/CdS multilayered spherical nanostructure

    Science.gov (United States)

    Holovatsky, V. A.; Bernik, I. B.; Yakhnevych, M. Ya.

    2017-03-01

    The theoretical investigation of magnetic field effect on energy spectrum and localization of the electron and oscillator strengths of intraband quantum transitions in the nanostructure CdS/HgS/CdS/HgS/CdS is performed. The calculations are made in the framework of effective mass approximation and rectangular potential barriers model using the method of the expansion of quasi-particle wave functions over the complete basis of functions obtained as the exact solutions of the Schrodinger equation for the electron in the nanostructure without the magnetic field. It is shown that the magnetic field violates the spherical symmetry of the system and takes off the degeneration of energy spectrum with respect to the magnetic quantum number. The energy of the electron in the states with m≥0 increases when magnetic field enhances; for the states with m<0 these dependences are non-monotonous (decreasing at first and then increasing). Moreover, the ground state of electron is formed alternately by the states with m=0, -1, -2, …. Magnetic field influences on the distribution of quasi-particle density. It is shown that the electron significantly changes its localization in the nanostructure with two potential wells tunneling through the potential barrier under the effect of magnetic field, changing the oscillator strengths of intraband quantum transitions.

  13. ASCA View of the Supernova Remnant Gamma Cygni (G78.2+2.1) Bremsstrahlung X-ray Spectrum from Loss-flattened Electron Distribution

    CERN Document Server

    Uchiyama, Y; Aharonian, F A; Mattox, J R; Uchiyama, Yasunobu; Takahashi, Tadayuki; Aharonian, Felix; Mattox, John

    2002-01-01

    We perform X-ray studies of the shell-type supernova remnant (SNR) gamma-Cygni associated with the brightest EGRET unidentified source 3EG J2020+4017. In addition to the thermal emissions with characteristic temperature of kT = 0.5-0.9 keV, we found an extremely hard X-ray component from several clumps localized in the northern part of the remnant. This component is described by a power-law with a photon index of 0.8-1.5. Both the absolute flux and the spectral shape of the nonthermal X-rays cannot be explained by the synchrotron or inverse-Compton mechanisms. We argue that the unusually hard X-ray spectrum can be naturally interpreted in terms of nonthermal bremsstrahlung from Coulomb-loss-flattened electron distribution in dense environs with the gas density about 10 to 100 cm^-3 . For given spectrum of the electron population, the ratio of the bremsstrahlung X- and gamma-ray fluxes depends on the position of the ``Coulomb break'' in the electron spectrum. The bulk of gamma-rays detected by EGRET would come...

  14. Pack-Year Cigarette Smoking History for Determination of Lung Cancer Screening Eligibility. Comparison of the Electronic Medical Record versus a Shared Decision-making Conversation.

    Science.gov (United States)

    Modin, Hannah E; Fathi, Joelle T; Gilbert, Christopher R; Wilshire, Candice L; Wilson, Andrew K; Aye, Ralph W; Farivar, Alexander S; Louie, Brian E; Vallières, Eric; Gorden, Jed A

    2017-08-01

    Implementation of lung cancer screening programs is occurring across the United States. Programs vary in approaches to patient identification and shared decision-making. The eligibility of persons referred to screening programs, the outcomes of eligibility determination during shared decision-making, and the potential for the electronic medical record (EMR) to identify eligible individuals have not been well described. Our objectives were to assess the eligibility of individuals referred for lung cancer screening and compare information extracted from the EMR to information derived from a shared decision-making conversation for the determination of eligibility for lung cancer screening. We performed a retrospective analysis of individuals referred to a centralized lung cancer screening program serving a five-hospital health services system in Seattle, Washington between October 2014 and January 2016. Demographics, referral, and outcomes data were collected. A pack-year smoking history derived from the EMR was compared with the pack-year history obtained during a shared decision-making conversation performed by a licensed nurse professional representing the lung cancer screening program. A total of 423 individuals were referred to the program, of whom 59.6% (252 of 423) were eligible. Of those, 88.9% (224 of 252) elected screening. There was 96.2% (230 of 239) discordance in pack-year smoking history between the EMR and the shared decision-making conversation. The EMR underreported pack-years of smoking for 85.2% (196 of 230) of the participants, with a median difference of 29.2 pack-years. If identification of eligible individuals relied solely on the accuracy of the pack-year smoking history recorded in the EMR, 53.6% (128 of 239) would have failed to meet the 30-pack-year threshold for screening. Many individuals referred for lung cancer screening may be ineligible. Overreliance on the EMR for identification of individuals at risk may lead to missed opportunities

  15. Conversion disorder

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000954.htm Conversion disorder To use the sharing features on this page, please enable JavaScript. Conversion disorder is a mental condition in which a person ...

  16. Generating Periodic Terahertz Structures in a Relativistic Electron Beam through Frequency Down-Conversion of Optical Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Dunning, Michael

    2012-07-19

    We report generation of density modulation at terahertz (THz) frequencies in a relativistic electron beam through laser modulation of the beam longitudinal phase space. We show that by modulating the energy distribution of the beam with two lasers, density modulation at the difference frequency of the two lasers can be generated after the beam passes through a chicane. In this experiment, density modulation around 10 THz was generated by down-converting the frequencies of an 800 nm laser and a 1550 nm laser. The central frequency of the density modulation can be tuned by varying the laser wavelengths, beam energy chirp, or momentum compaction of the chicane. This technique can be applied to accelerator-based light sources for generation of coherent THz radiation and marks a significant advance toward tunable narrow-band THz sources.

  17. Optimization of an Electron Transport Layer to Enhance the Power Conversion Efficiency of Flexible Inverted Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Lee Kang Hyuck

    2010-01-01

    Full Text Available Abstract The photovoltaic (PV performance of flexible inverted organic solar cells (IOSCs with an active layer consisting of a blend of poly(3-hexylthiophene and [6, 6]-phenyl C61-butlyric acid methyl ester was investigated by varying the thicknesses of ZnO seed layers and introducing ZnO nanorods (NRs. A ZnO seed layer or ZnO NRs grown on the seed layer were used as an electron transport layer and pathway to optimize PV performance. ZnO seed layers were deposited using spin coating at 3,000 rpm for 30 s onto indium tin oxide (ITO-coated polyethersulphone (PES substrates. The ZnO NRs were grown using an aqueous solution method at a low temperature (90°C. The optimized device with ZnO NRs exhibited a threefold increase in PV performance compared with that of a device consisting of a ZnO seed layer without ZnO NRs. Flexible IOSCs fabricated using ZnO NRs with improved PV performance may pave the way for the development of PV devices with larger interface areas for effective exciton dissociation and continuous carrier transport paths.

  18. On the perspectives of wide-band gap power devices in electronic-based power conversion for renewable systems

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos Araujo, Samuel

    2013-10-01

    The high breakdown field from WBG materials allows the construction of unipolar devices with very low specific chip resistance mainly characterized by very low conduction and switching losses, even at high blocking voltages. Suitable concepts for SiC and GaN range from traditional FET structures driven by a MOS interface or a PN-Junction, bipolar devices and even high-electron mobility transistors (HEMT). A detailed revision of the literature will be performed in this work with the objective of providing a broad overview of possible approaches, along with inherent advantages and limitations. In addition to this, a benchmarking of several SiC-based devices technologies rated for 1200 V and 1700 V will be performed against their state-of-the-art Silicon-counterparts. Concerning the application of wide band gap devices in renewable energy systems, a significant cost reduction potential can be obtained due to smaller expenditure with magnetic filters and cooling, alongside higher efficiency levels. These aspects will be discussed in details in order to identify constraints and bottlenecks at application level with special focus on photovoltaic and wind power systems.

  19. Optimization of an Electron Transport Layer to Enhance the Power Conversion Efficiency of Flexible Inverted Organic Solar Cells.

    Science.gov (United States)

    Lee, Kang Hyuck; Kumar, Brijesh; Park, Hye-Jeong; Kim, Sang-Woo

    2010-08-31

    The photovoltaic (PV) performance of flexible inverted organic solar cells (IOSCs) with an active layer consisting of a blend of poly(3-hexylthiophene) and [6, 6]-phenyl C(61)-butlyric acid methyl ester was investigated by varying the thicknesses of ZnO seed layers and introducing ZnO nanorods (NRs). A ZnO seed layer or ZnO NRs grown on the seed layer were used as an electron transport layer and pathway to optimize PV performance. ZnO seed layers were deposited using spin coating at 3,000 rpm for 30 s onto indium tin oxide (ITO)-coated polyethersulphone (PES) substrates. The ZnO NRs were grown using an aqueous solution method at a low temperature (90°C). The optimized device with ZnO NRs exhibited a threefold increase in PV performance compared with that of a device consisting of a ZnO seed layer without ZnO NRs. Flexible IOSCs fabricated using ZnO NRs with improved PV performance may pave the way for the development of PV devices with larger interface areas for effective exciton dissociation and continuous carrier transport paths.

  20. Spectroscopic diagnostics of electron temperature and energy conversion efficiency of laser-sustained plasma in flowing argon

    Science.gov (United States)

    Mazumder, J.; Krier, H.; Chen, X.

    1988-08-01

    Laser sustained plasmas are often formed during laser materials interaction. The University's 10 kW CW CO2 laser has been used to study argon plasmas for the application to laser supported propulsion and laser materials processing. The spectroscopic diagnostic method has been applied to study laser-sustained plasmas in 1 atmosphere pure argon gas flow with an f/7 on-axis laser focusing scheme. High flow speeds of 2 to 10 m/sec are achieved. Plasma electron temperatures distributions are determined from the 415.8 nm Ar1 line and its adjacent continuum intensities. Plasma core temperatures as high as 20,000 K are reported. The total absorption of the incident laser power and the radiation loss by the plasma are calculated from the temperature distribution. Results indicated that up to 86 percent of the incident laser power can be absorbed and nearly 60 percent of the incident laser power can be retained by the flowing argon gas to provide thrust. Further research is called for in the Laser Induced Fluorescence (LIF) technique for diagnostics of the downstream mixing zone and the plasma outer region. Experiments over a wider range of operating conditions, as well as multiple plasma testings, are required to find the optimum operating scheme.

  1. Remarkably High Conversion Efficiency of Inverted Bulk Heterojunction Solar Cells: From Ultrafast Laser Spectroscopy and Electron Microscopy to Device Fabrication and Optimization

    KAUST Repository

    Alsulami, Qana

    2016-04-10

    In organic donor-acceptor systems, ultrafast interfacial charge transfer (CT), charge separation (CS), and charge recombination (CR) are key determinants of the overall performance of photovoltaic devices. However, a profound understanding of these photophysical processes at device interfaces remains superficial, creating a major bottleneck that circumvents advancements and the optimization of these solar cells. Here, results from time-resolved laser spectroscopy and high-resolution electron microscopy are examined to provide the fundamental information necessary to fabricate and optimize organic solar cell devices. In real time, CT and CS are monitored at the interface between three fullerene acceptors (FAs) (PC71BM, PC61BM, and IC60BA) and the PTB7-Th donor polymer. Femtosecond transient absorption (fs-TA) data demonstrates that photoinduced electron transfer from the PTB7-Th polymer to each FA occurs on the sub-picosecond time scale, leading to the formation of long-lived radical ions. It is also found that the power conversion efficiency improves from 2% in IC60BA-based solar cells to >9% in PC71BM-based devices, in support of our time-resolved results. The insights reported in this manuscript provide a clear understanding of the key variables involved at the device interface, paving the way for the exploitation of efficient CS and subsequently improving the photoconversion efficiency. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. iPad: Efficacy of Electronic Devices to Help Children with Autism Spectrum Disorder to Communicate in the Classroom

    Science.gov (United States)

    Sankardas, Sulata Ajit; Rajanahally, Jayashree

    2017-01-01

    Children with Autism Spectrum Disorder (ASD) are known to have difficulty in social communication, with research indicating that children with ASD fail to develop functional speech (Lord and Rutter, 1994). Over the years a number of Augmented and Alternate Communication (AAC) devices have been used with children with ASD to overcome this barrier…

  3. Ab-initio primitive cell parameters from single convergent-beam electron diffraction patterns: a converse route to the identification of microcrystals with electrons.

    Science.gov (United States)

    Le Page, Y

    1992-04-01

    A new method for the ab initio derivation of Buerger-reduced primitive cell parameters from coordinate measurements of spots on single convergent-beam electron diffraction (CBED) patterns is described, which does not involve trial-and-error. The pattern can be taken along any zone axis, and misorientations of the crystallite by as much as a few degrees are taken into account without loss of accuracy. This derivation of cell parameters by least-squares analysis of the measurements has been automated in a program called NRCBED. Present accuracy is about 1% on lengths and 2 degrees on angles, but could be significantly improved by modelling projector lens aberrations, or by using a microscope without a projector lens. With present technology, it is possible to obtain a CBED pattern and a semi-quantitative energy-dispersive X-ray (EDX) analysis simultaneously from a single microcrystal a few hundred Angströms across. It becomes therefore possible to identify the material of the crystal on a single CBED pattern: a cell parameter database for known compounds is searched with the primitive cell parameters obtained in the above way, and with a mask describing the EDX results qualitatively. Feasibility is demonstrated on a crystallite of CeO2 500 Angströms across. With this new approach, trial-and-error should disappear from the solution of other long-standing problems: interpretation of X-ray powder patterns for new compounds in the presence of impurity lines, or in the case of multiple phases should become straight-forward.

  4. Confocal Raman and electronic microscopy studies on the topotactic conversion of calcium carbonate from Pomacea lineate shells into hydroxyapatite bioceramic materials in phosphate media.

    Science.gov (United States)

    dePaula, S M; Huila, M F G; Araki, K; Toma, H E

    2010-12-01

    Conversion of Pomacea lineate shells into hydroxyapatite (HA) bioceramic materials was investigated by their in vitro treatment with phosphate solutions, at room temperature. Confocal Raman microscopy revealed that the conversion proceeds at distinct rates through the nacreous or periostracum sides of the shell. The conversion can be accelerated using powdered samples, yielding biocompatible materials of great interest in biomedicine.

  5. Forming of space charge wave with broad frequency spectrum in helical relativistic two-stream electron beams

    DEFF Research Database (Denmark)

    Lysenko, Alexander V.; Volk, Iurii I.; Serozhko, A.

    2017-01-01

    We elaborate a quadratic nonlinear theory of plural interactions of growing space charge wave (SCW) harmonics during the development of the two-stream instability in helical relativistic electron beams. It is found that in helical two-stream electron beams the growth rate of the two-stream instab...

  6. Ultrafast spectroscopy studies on the mechanism of electron transfer and energy conversion in the isolated pseudo ginseng, water hyacinth and spinach chloroplasts

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The spectroscopy characteristics and the fluorescence lifetime for the chloroplasts isolated from the pseudo ginseng, water hyacinth and spinach plant leaves have been studied by absorption spectra, low temperature steady-state fluorescence spectroscopy and single photon counting measurement under the same conditions and by the same methods. The similarity of the absorption spectra for the chloroplasts at room temperature suggests that different plants can efficiently absorb light of the same wavelength. The fluorescence decays in PS II measured at the natural QA state for the chloroplasts have been fitted by a three-exponential kinetic model. The three fluorescence lifetimes are 30, 274 and 805 ps for the pseudo ginseng chloroplast; 138, 521 and 1494 ps for the water hyacinth chloroplast; 197, 465 and 1459 ps for the spinach chloroplast, respectively. The slow lifetime fluorescence component is assigned to a collection of associated light harvesting Chl a/b proteins, the fast lifetime component to the reaction center of PS II and the middle lifetime component to the delay fluorescence of recombination of and Pheo-. The excitation energy conversion efficiency (η) in PS II RC is defined and calculated on the basis of the 20 ps electron transfer time constant model, 60%, 87% and 91% for the pseudo ginseng, water hyacinth and spinach chloroplasts, respectively. This interesting result is in unconformity with what is assumed to be 100% efficiency in PS II RC. Our result in this work stands in line with the 20 ps electron transfer time constant in PS II rather sound and the water hyacinth plant grows slower than the spinach plant does as envisaged on the efficiency. But, our results predict that those plants can perform highly efficient transfer of photo-excitation energy from the light-harvesting pigment system to the reaction center (closely to 100%). The conclusion contained in this paper reveals the plant growth characteristics expressed in the primary processes of

  7. Effect of Short-Circuit Faults in the Back-to-Back Power Electronic Converter and Rotor Terminals on the Operational Behavior of the Doubly-Fed Induction Generator Wind Energy Conversion System

    Directory of Open Access Journals (Sweden)

    Dimitrios G. Giaourakis

    2015-02-01

    Full Text Available This paper deals with the operational behavior of the Doubly-Fed Induction Generator Wind Energy Conversion System under power electronic converter and rotor terminals faulty conditions. More specifically, the effect of the short-circuit fault both in one IGBT of the back-to-back power electronic converter and in rotor phases on the overall system behavior has been investigated via simulation using a system of 2 MW. Finally, the consequences of these faults have been evaluated.

  8. Obtaining the conversion curve of CT numbers to electron density from the effective energy of the CT using the dummy SEFM; Obtencion de la curva de conversion de numeros TC a densidad electronica a partir de la energia efectiva del TC usando el maniqui de la SEFM

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Viera Cueto, J. A.; Garcia Pareja, S.; Benitez Villegas, E. M.; Moreno Saiz, E. M.; Bodineau Gil, C.; Caudepon Moreno, F.

    2011-07-01

    The objective of this work is to obtain the conversion curve of Hounsfield units (A) versus electron densities using a mannequin with different tissue equivalent materials. This provides for the effective energy beam CT and is used to characterize the linear coefficients of absorption of different materials that comprise the dummy.

  9. Conversational Narcissism.

    Science.gov (United States)

    Vangelisti, Anita L.; And Others

    1990-01-01

    Examines narcissistic communication and the ways it is exhibited in everyday conversation. Identifies the following behavioral referents: boasting, refocusing the topic of conversation on the self, exaggerating hand and body movements, using a loud tone of voice, and "glazing over" when others speak. Suggests that conversational…

  10. Contentious Conversations

    Science.gov (United States)

    Zuidema, Leah A.

    2011-01-01

    The idea of joining a conversation through reading and writing is not new; in his 1941 book "The Philosophy of Literary Form: Studies in Symbolic Action," Kenneth Burke suggests that the acts of reading and writing are like entering a parlor where others are already conversing. The author explores the place of professional debate within NCTE and…

  11. Resonanant enhancement of molecular excitation intensity in inelastic electron scattering spectrum owing to interaction with plasmons in metallic nanoshell

    CERN Document Server

    Goliney, I Yu

    2014-01-01

    A quantum-mechanical model to calculate the electron energy-loss spectra (EELS) for the system of a closely located metallic nanoshell and a molecule has been developed. At the resonance between the molecular excitation and plasmon modes in the nanoshell, which can be provided by a proper choice of the ratio of the inner and outer nanoshell radii, the cross-section of inelastic electron scattering at the molecular excitation energy is shown to grow significantly, because the molecular transition borrows the oscillator strength from a plasmon. The enhancement of the inelastic electron scattering by the molecule makes it possible to observe molecular transitions with an electron microscope. The dependences of the EEL spectra on the relative arrangement of the molecule and the nanoshell, the ratio between the inner and outer nanoshell radii, and the scattering angle are plotted and analyzed.

  12. Selective detection of Fe and Mn species at mineral surfaces in weathered granite by conversion electron yield X-ray absorption fine structure

    Energy Technology Data Exchange (ETDEWEB)

    Itai, Takaaki [Department of Earth and Planetary Systems Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)], E-mail: itai-epss@hiroshima-u.ac.jp; Takahashi, Yoshio [Department of Earth and Planetary Systems Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Uruga, Tomoya; Tanida, Hajime [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Iida, Atsuo [Photon Factory, National Laboratory for High Energy Physics, O-ho, Tsukuba, Ibaraki 305 (Japan)

    2008-09-15

    A new method for the speciation of Fe and Mn at mineral surfaces is proposed using X-ray absorption fine structure in conversion electron yield mode (CEY-XAFS). This method generally reflects information on the species at the sub-{mu}m scale from the particle surface due to the limited escape depth of the inelastic Auger electron. The surface sensitivity of this method was assessed by experiments on two samples of granite showing different degrees of weathering. The XANES spectra of the Fe-K and Mn-K edge clearly gave different information for CEY and fluorescence (FL) modes. These XANES spectra of Fe and Mn show a good fit upon application of least-squares fitting using ferrihydrite/MnO{sub 2} and biotite as the end members. The XANES spectra collected by CEY mode provided more selective information on the secondary phases which are probably present at the mineral surfaces. In particular, CEY-XANES spectra of Mn indicated the presence of Mn oxide in unweathered granite despite a very small contribution of Mn oxide being indicated by FL-XANES and selective chemical-extraction analyses. Manganese oxide could not be detected by micro-beam XANES (beam size: 5 x 5 {mu}m{sup 2}) in unweathered granite, suggesting that Mn oxide thinly and ubiquitously coats mineral surface at a sub-{mu}m scale. This information is important, since Mn oxide can be the host for various trace elements. CEY-XAFS can prove to be a powerful tool as a highly sensitive surface speciation method. Combination of CEY and FL-XAFS will help identify minor phases that form at mineral surfaces, but identification of Fe and Mn oxides at mineral surfaces is critical to understand the migration of trace elements in water-rock interaction.

  13. Iron silicide formation at different layers of (Fe/Si){sub 3} multilayered structures determined by conversion electron Mössbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Badía-Romano, L., E-mail: lbadia@unizar.es; Bartolomé, J. [Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, E-50009 Zaragoza (Spain); Rubín, J. [Departamento de Ciencia y Tecnología de Materiales y Fluidos, Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, E-50018 Zaragoza (Spain); Magén, C. [Laboratorio de Microscopías Avanzadas (LMA), Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, E-50018 Zaragoza (Spain); Bürgler, D. E. [Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany)

    2014-07-14

    The morphology and the quantitative composition of the Fe-Si interface layer forming at each Fe layer of a (Fe/Si){sub 3} multilayer have been determined by means of conversion electron Mössbauer spectroscopy (CEMS) and high-resolution transmission electron microscopy (HRTEM). For the CEMS measurements, each layer was selected by depositing the Mössbauer active {sup 57}Fe isotope with 95% enrichment. Samples with Fe layers of nominal thickness d{sub Fe} = 2.6 nm and Si spacers of d{sub Si} = 1.5 nm were prepared by thermal evaporation onto a GaAs(001) substrate with an intermediate Ag(001) buffer layer. HRTEM images showed that Si layers grow amorphous and the epitaxial growth of the Fe is good only for the first deposited layer. The CEMS spectra show that at all Fe/Si and Si/Fe interfaces a paramagnetic c-Fe{sub 1−x}Si phase is formed, which contains 16% of the nominal Fe deposited in the Fe layer. The bottom Fe layer, which is in contact with the Ag buffer, also contains α-Fe and an Fe{sub 1−x}Si{sub x} alloy that cannot be attributed to a single phase. In contrast, the other two layers only comprise an Fe{sub 1−x}Si{sub x} alloy with a Si concentration of ≃0.15, but no α-Fe.

  14. Resonanant enhancement of molecular excitation intensity in inelastic electron scattering spectrum owing to interaction with plasmons in metallic nanoshell

    OpenAIRE

    Goliney, I. Yu.; Onykienko, Ye. V.

    2014-01-01

    A quantum-mechanical model to calculate the electron energy-loss spectra (EELS) for the system of a closely located metallic nanoshell and a molecule has been developed. At the resonance between the molecular excitation and plasmon modes in the nanoshell, which can be provided by a proper choice of the ratio of the inner and outer nanoshell radii, the cross-section of inelastic electron scattering at the molecular excitation energy is shown to grow significantly, because the molecular transit...

  15. Differential cross sections and oscillator strengths in electron energy loss spectrum of b1Пu electronic state of N2

    Institute of Scientific and Technical Information of China (English)

    徐克尊; 钟志萍; 武淑兰; 凤任飞; S.Ohtani; T.Takayanagi; A.Kimota

    1995-01-01

    The energy loss spectrum of the molecular nitrogen in the energy region 12 -14 eV has been measured at 300 eV impact energy and in the range of scattering angles of 2.75℃- 10.25℃. The differential cross sections and generalized oscillator strengths have been determined for individual vibronic excitation band (v’ = 1 - 4) of b1Пu from the ground state of N2 and the absolute optical oscillator strengths have also been obtained by taking the limit of K→ 0. Results have been compared with experimental data and theoretical calculations previously published.

  16. Structure and 57Fe conversion electron M(o)ssbauer spectroscopy study of Mn-Zn ferrite nanocrystal thin films by electroless plating in aqueous solution

    Institute of Scientific and Technical Information of China (English)

    SUN JianRong; WANG XueWen; LIU JinHong; WANG JianBo; LI FaShen

    2008-01-01

    Mn1-xZnxFe2O4 thin films with various Zn contents and of different thickness were synthesized on glass substrates directly by electroless plating in aqueous solution at 90℃ without heat treatment. The Mn-Zn ferrite films have a single spinel phase structure and well-crystallized columnar grains growing per-pendicularly to the substrates. The results of conversion electron 57Fe Mossbauer spectroscopy (CEMS) indicate that the cation distribution of Mn-xZnxFe2O4 ferrite nanocrystal thin films fabricated by elec-troless plating is different from the bulk materials' and a great quantity of Fe3+ ions are still present on A sites for x>0.5. When the Zn content of the films increases, Fe3+ ions in the films transfer from A sites to B sites and the hyperfine magnetic field reduces, suggesting that Zn2+ has strong chemical affinity towards the A sites. On the other side, with the increase of the thickness of the films, Fe3+ ions, at B sites in the spinel structure, increase and the array of magnetic moments no longer lies in the thin film plane completely. At x=0.5, Hc and Ms of Mn1-xZnxFe2O4 thin films show a minimum of 3.7 kA/m and a maximum of 419.6 kA/m, respectively.

  17. Development of a sampling method for carbonyl compounds released due to the use of electronic cigarettes and quantitation of their conversion from liquid to aerosol.

    Science.gov (United States)

    Jo, Sang-Hee; Kim, Ki-Hyun

    2016-01-15

    In this study, an experimental method for the collection and analysis of carbonyl compounds (CCs) released due to the use of electronic cigarettes (e-cigarettes or ECs) was developed and validated through a series of laboratory experiments. As part of this work, the conversion of CCs from a refill solution (e-solution) to aerosol also was investigated based on mass change tracking (MCT) approach. Aerosol samples generated from an e-cigarette were collected manually using 2,4-dinitrophenylhydrazine (DNPH) cartridges at a constant sampling (puffing) velocity of 1 L min(-1) with the following puff conditions: puff duration (2s), interpuff interval (10s), and puff number (5, 10, and 15 times). The MCT approach allowed us to improve the sampling of CCs through critical evaluation of the puff conditions in relation to the consumed quantities of refill solution. The emission concentrations of CCs remained constant when e-cigarettes were sampled at or above 10 puff. Upon aerosolization, the concentrations of formaldehyde and acetaldehyde increased 6.23- and 58.4-fold, respectively, relative to their concentrations in e-solution. Furthermore, a number of CCs were found to be present in the aerosol samples which were not detected in the initial e-solution (e.g., acetone, butyraldehyde, and o-tolualdehyde).

  18. Effect of Rashba and Dresselhaus interactions on the energy spectrum, chemical potential, addition energy and spin-splitting in a many-electron parabolic GaAs quantum dot in a magnetic field

    Science.gov (United States)

    Kumar, D. Sanjeev; Mukhopadhyay, Soma; Chatterjee, Ashok

    2016-11-01

    The effect of electron-electron interaction and the Rashba and Dresselhaus spin-orbit interactions on the electronic properties of a many-electron system in a parabolically confined quantum dot placed in an external magnetic field is studied. With a simple and physically reasonable model potential for electron-electron interaction term, the problem is solved exactly to second-order in the spin-orbit coupling constants to obtain the energy spectrum, the chemical potential, addition energy and the spin-splitting energy.

  19. Power electronics advanced conversion technologies

    CERN Document Server

    Luo, Fang Lin

    2010-01-01

    Introduction Symbols and Factors Used in This Book AC/DC Rectifiers DC/DC Converters DC/AC Inverters AC/AC Converters AC/DC/AC and DC/AC/DC Converters Uncontrolled AC/DC Converters Single-Phase Half-Wave Converters Single-Phase Full-Wave Converters Three-Phase Half-Wave Converters Six-Phase Half-Wave Converters Three-Phase Full-Wave Converters Multiphase Full-Wave Converters Controlled AC/DC Converters Single-Phase Half-Wave Controlled Converters Single-Phase Full-Wave Controlled Converters Three-Phase Half-Wave Controlled Rectifiers Six-Phase Half-Wave Controlled Rectifiers Three-Phase Full-W

  20. Dose-rate conversion factors for external exposure to photon and electron radiation from radionuclides occurring in routine releases from nuclear fuel cycle facilities. [Conversion factors are given for dose rates to 21 organs from 240 different radionuclides for 3 different modes of exposure

    Energy Technology Data Exchange (ETDEWEB)

    Kocher, D.C.

    1979-02-01

    Dose-rate conversion factors for external exposure to photon and electron radiation have been calculated for 240 radionuclides of potential importance in routine releases from nuclear fuel cycle facilities. Dose-rate conversion factors for immersion in contaminated air, immersion in contaminated water, and exposure to a contaminated ground surface are estimated for tissue-equivalent material at the body surface of an exposed individual. For each exposure mode, photon dose-rate conversion factors are also estimated for 22 body organs. The calculations assume that the contaminated air, water, and ground surface are infinite in extent and that the radionuclide concentration is uniform. Dose-rate conversion factors for immersion in contaminated air and water are based on the requirement that all energy emitted in the decay of a radionuclide is absorbed in the infinite medium. Dose-rate conversion factors for ground-surface exposure are calculated for a height of 1 m using the point-kernel integration method and known specific absorbed fractions for photons and electrons in air. The computer code DOSFACTER written to perform the calculations is described and documented.

  1. Di-electron spectrum at mid-rapidity in $p+p$ collisions at $\\sqrt{s} = 200$ GeV

    CERN Document Server

    Adamczyk, L; Aggarwal, M M; Ahammed, Z; Alakhverdyants, A V; Alekseev, I; Alford, J; Anderson, B D; Anson, C D; Arkhipkin, D; Aschenauer, E; Averichev, G S; Balewski, J; Banerjee, A; Barnovska, Z; Beavis, D R; Bellwied, R; Betancourt, M J; Betts, R R; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Borowski, W; Bouchet, J; Brandin, A V; Brovko, S G; Bruna, E; Bueltmann, S; Bunzarov, I; Burton, T P; Butterworth, J; Cai, X Z; Caines, H; Sánchez, M Calderón de la Barca; Cebra, D; Cendejas, R; Cervantes, M C; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, J Y; Chen, L; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chung, P; Chwastowski, J; Codrington, M J M; Corliss, R; Cramer, J G; Crawford, H J; Cui, X; Leyva, A Davila; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; de Souza, R Derradi; Dhamija, S; Didenko, L; Ding, F; Dion, A; Djawotho, P; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Elnimr, M; Engelage, J; Eppley, G; Eun, L; Evdokimov, O; Fatemi, R; Fazio, S; Fedorisin, J; Fersch, R G; Filip, P; Finch, E; Fisyak, Y; Gagliardi, C A; Gangadharan, D R; Geurts, F; Gibson, A; Gliske, S; Gorbunov, Y N; Grebenyuk, O G; Grosnick, D; Gupta, S; Guryn, W; Haag, B; Hajkova, O; Hamed, A; Han, L-X; Harris, J W; Hays-Wehle, J P; Heppelmann, S; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, B; Huang, H Z; Huck, P; Humanic, T J; Huo, L; Igo, G; Jacobs, W W; Jena, C; Joseph, J; Judd, E G; Kabana, S; Kang, K; Kapitan, J; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Kesich, A; Kettler, D; Kikola, D P; Kiryluk, J; Kisel, I; Kisiel, A; Kizka, V; Klein, S R; Koetke, D D; Kollegger, T; Konzer, J; Koralt, I; Koroleva, L; Korsch, W; Kotchenda, L; Kravtsov, P; Krueger, K; Kulakov,; Kumar, L; Lamont, M A C; Landgraf, J M; LaPointe, S; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; Leight, W; LeVine, M J; Li, C; Li, L; Li, W; Li, X; Li, X; Li, Y; Li, Z M; Lima, L M; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Longacre, R S; Lu, Y; Luo, X; Luszczak, A; Ma, G L; Ma, Y G; Don, D M M D Madagodagettige; Mahapatra, D P; Majka, R; Mall, O I; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; McShane, T S; Mioduszewski, S; Mitrovski, M K; Mohammed, Y; Mohanty, B; Mondal, M M; Morozov, B; Munhoz, M G; Mustafa, M K; Naglis, M; Nandi, B K; Nasim, Md; Nayak, T K; Nelson, J M; Nogach, L V; Novak, J; Odyniec, G; Ogawa, A; Oh, K; Ohlson, A; Okorokov, V; Oldag, E W; Oliveira, R A N; Olson, D; Ostrowski, P; Pachr, M; Page, B S; Pal, S K; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlak, T; Pawlik, B; Pei, H; Perkins, C; Peryt, W; Pile, P; Planinic, M; Pluta, J; Plyku, D; Poljak, N; Porter, J; Poskanzer, A M; Powell, C B; Prindle, D; Pruneau, C; Pruthi, N K; Przybycien, M; Pujahari, P R; Putschke, J; Qiu, H; Raniwala, R; Raniwala, S; Ray, R L; Redwine, R; Reed, R; Riley, C K; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Ross, J F; Ruan, L; Rusnak, J; Sahoo, N R; Sakrejda, I; Salur, S; Sandacz, A; Sandweiss, J; Sangaline, E; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, B; Schmitz, N; Schuster, T R; Seele, J; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shao, M; Sharma, B; Sharma, M; Shi, S S; Shou, Q Y; Sichtermann, E P; Singaraju, R N; Skoby, M J; Smirnov, D; Smirnov, N; Solanki, D; Sorensen, P; deSouza, U G; Spinka, H M; Srivastava, B; Stanislaus, T D S; Steadman, S G; Stevens, J R; Stock, R; Strikhanov, M; Stringfellow, B; Suaide, A A P; Suarez, M C; Sumbera, M; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Svirida, D N; Symons, T J M; de Toledo, A Szanto; Takahashi, J; Tang, A H; Tang, Z; Tarini, L H; Tarnowsky, T; Thein, D; Thomas, J H; Tian, J; Timmins, A R; Tlusty, D; Tokarev, M; Trainor, T A; Trentalange, S; Tribble, R E; Tribedy, P; Trzeciak, B A; Tsai, O D; Turnau, J; Ullrich, T; Underwood, D G; Van Buren, G; van Nieuwenhuizen, G; Vanfossen, J A; Jr.,; Varma, R; Vasconcelos, G M S; Videbæk, F; Viyogi, Y P; Vokal, S; Voloshin, S A; Vossen, A; Wada, M; Wang, F; Wang, G; Wang, H; Wang, J S; Wang, Q; Wang, X L; Wang, Y; Webb, G; Webb, J C; Westfall, G D; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Witzke, W; Wu, Y F; Xiao, Z; Xie, W; Xin, K; Xu, H; Xu, N; Xu, Q H; Xu, W; Xu, Y; Xu, Z; Xue, L; Yang, Y; Yang, Y; Yepes, P; Yi, Y; Yip, K; Yoo, I-K; Zawisza, M; Zbroszczyk, H; Zhang, J B; Zhang, S; Zhang, W M; Zhang, X P; Zhang, Y; Zhang, Z P; Zhao, F; Zhao, J; Zhong, C; Zhu, X; Zhu, Y H; Zoulkarneeva, Y; Zyzak, M

    2012-01-01

    We report on mid-rapidity mass spectrum of di-electrons and cross sections of pseudoscalar and vector mesons via $e^{+}e^{-}$ decays, from $\\sqrt{s} = 200$ GeV $p+p$ collisions, measured by the large acceptance experiment STAR at RHIC. The ratio of the di-electron continuum to the combinatorial background is larger than 10% over the entire mass range. Simulations of di-electrons from light-meson decays and heavy-flavor decays (charmonium and open charm correlation) are found to describe the data. The extracted $\\omega\\rightarrow e^{+}e^{-}$ invariant yields are consistent with previous measurements. The mid-rapidity yields ($dN/dy$) of $\\phi$ and $J/\\psi$ are extracted through their di-electron decay channels and are consistent with the previous measurements of $\\phi\\rightarrow K^{+}K^{-}$ and $J/\\psi\\rightarrow e^{+}e^{-}$. Our results suggest a new upper limit of the branching ratio of the $\\eta \\rightarrow e^{+}e^{-}$ of $1.7\\times10^{-5}$ at 90% confidence level.

  2. The kinetic energy spectrum of protons produced by the dissociative ionization of H2 by electron impact

    Science.gov (United States)

    Khakoo, M. A.; Srivastava, S. K.

    1985-01-01

    The kinetic energy spectra of protons resulting from the dissociative ionization of H2 by electron impact have been measured for electron impact energies from threshold (approximately 17 eV) to 160 eV at 90 deg and 30 deg detection angles, using a crossed-beam experimental arrangement. To check reliability, two separate proton energy analysis methods have been employed, i.e., a time-of-flight proton energy analysis and an electrostatic hemispherical energy analyzer. The present results are compared with previous measurements.

  3. Morphology of gold nanoparticles determined by full-curve fitting of the light absorption spectrum. Comparison with X-ray scattering and electron microscopy data

    Science.gov (United States)

    Slyusarenko, Kostyantyn; Abécassis, Benjamin; Davidson, Patrick; Constantin, Doru

    2014-10-01

    UV-Vis absorption spectroscopy is frequently used to characterize the size and shape of gold nanoparticles. We present a full-spectrum model that yields reliable results for the commonly encountered case of mixtures of spheres and rods in varying proportions. We determine the volume fractions of the two populations, the aspect ratio distribution of the nanorods (average value and variance) and the interface damping parameter. We validate the model by checking the fit results against small-angle X-ray scattering and transmission electron microscopy data and show that correctly accounting for the polydispersity in aspect ratio is essential for a quantitative description of the longitudinal plasmon peak.UV-Vis absorption spectroscopy is frequently used to characterize the size and shape of gold nanoparticles. We present a full-spectrum model that yields reliable results for the commonly encountered case of mixtures of spheres and rods in varying proportions. We determine the volume fractions of the two populations, the aspect ratio distribution of the nanorods (average value and variance) and the interface damping parameter. We validate the model by checking the fit results against small-angle X-ray scattering and transmission electron microscopy data and show that correctly accounting for the polydispersity in aspect ratio is essential for a quantitative description of the longitudinal plasmon peak. Electronic supplementary information (ESI) available: TEM images of nanoparticles and detailed analysis, simplified relations for the AS model, alternative estimate for the concentration and discussion of the dielectric constant chosen for bulk gold. See DOI: 10.1039/c4nr04155k

  4. Influence of manganese concentration on the electron magnetic resonance spectrum of Mn{sup 2+} in CdO

    Energy Technology Data Exchange (ETDEWEB)

    Biasi, R.S. de, E-mail: rsbiasi@ime.eb.b [Departamento de Engenharia Mecanica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro, RJ (Brazil); Grillo, M.L.N. [Instituto de Fisica, Universidade do Estado do Rio de Janeiro, 20550-013 Rio de Janeiro, RJ (Brazil)

    2009-10-19

    Electron magnetic resonance spectra of manganese-doped cadmium oxide (CdO) have been studied at room temperature for Mn concentrations between 0.10 and 1.00 mol%. The results suggest that the range of the exchange interaction between Mn{sup 2+} ions is about 0.56 nm.

  5. Conversion Disorder

    Science.gov (United States)

    ... Recent significant stress or emotional trauma Being female — women are much more likely to develop conversion disorder Having a mental health condition, such as mood or anxiety disorders, dissociative disorder or certain personality disorders Having ...

  6. Conversation Analysis.

    Science.gov (United States)

    Schiffrin, Deborah

    1990-01-01

    Summarizes the current state of research in conversation analysis, referring primarily to six different perspectives that have developed from the philosophy, sociology, anthropology, and linguistics disciplines. These include pragmatics; speech act theory; interactional sociolinguistics; ethnomethodology; ethnography of communication; and…

  7. Conversation Analysis.

    Science.gov (United States)

    Schiffrin, Deborah

    1990-01-01

    Summarizes the current state of research in conversation analysis, referring primarily to six different perspectives that have developed from the philosophy, sociology, anthropology, and linguistics disciplines. These include pragmatics; speech act theory; interactional sociolinguistics; ethnomethodology; ethnography of communication; and…

  8. Strategic conversation

    Directory of Open Access Journals (Sweden)

    Nicholas Asher

    2013-08-01

    Full Text Available Models of conversation that rely on a strong notion of cooperation don’t apply to strategic conversation — that is, to conversation where the agents’ motives don’t align, such as courtroom cross examination and political debate. We provide a game-theoretic framework that provides an analysis of both cooperative and strategic conversation. Our analysis features a new notion of safety that applies to implicatures: an implicature is safe when it can be reliably treated as a matter of public record. We explore the safety of implicatures within cooperative and non cooperative settings. We then provide a symbolic model enabling us (i to prove a correspondence result between a characterisation of conversation in terms of an alignment of players’ preferences and one where Gricean principles of cooperative conversation like Sincerity hold, and (ii to show when an implicature is safe and when it is not. http://dx.doi.org/10.3765/sp.6.2 BibTeX info

  9. Measurement of the W Boson Mass with the D0 Run II Detector using the Electron P(T) Spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Andeen, Jr., Timothy R. [Northwestern Univ., Evanston, IL (United States)

    2008-06-01

    This thesis is a description of the measurement of the W boson mass using the D0 Run II detector with 770 pb-1 of p$\\bar{p}$ collision data. These collisions were produced by the Tevatron at √s = 1.96 TeV between 2002 and 2006. We use a sample of W → ev and Z → ee decays to determine the W boson mass with the transverse momentum distribution of the electron and the transverse mass distribution of the boson. We measure MW = 80340 ± 37 (stat.) ± 26 (sys. theo.) ± 51 (sys. exp.) MeV = 80340 ± 68 MeV with the transverse momentum distribution of the electron and MW = 80361 ± 28 (stat.) ± 17 (sys. theo.) ± 51 (sys. exp.) MeV = 80361 ± 61 MeV with the transverse mass distribution.

  10. Research Investigation Directed Toward Extending the Useful Range of the Electromagnetic Spectrum. [atomic spectra and electronic structure of alkali metals

    Science.gov (United States)

    Hartmann, S. R.; Happer, W.

    1974-01-01

    The report discusses completed and proposed research in atomic and molecular physics conducted at the Columbia Radiation Laboratory from July 1972 to June 1973. Central topics described include the atomic spectra and electronic structure of alkali metals and helium, molecular microwave spectroscopy, the resonance physics of photon echoes in some solid state systems (including Raman echoes, superradiance, and two photon absorption), and liquid helium superfluidity.

  11. Probing Lewis Acid-Base Interactions with Born-Oppenheimer Molecular Dynamics: The Electronic Absorption Spectrum of p-Nitroaniline in Supercritical CO2.

    Science.gov (United States)

    Cabral, Benedito J Costa; Rivelino, Roberto; Coutinho, Kaline; Canuto, Sylvio

    2015-07-02

    The structure and dynamics of p-nitroaniline (PNA) in supercritical CO2 (scCO2) at T = 315 K and ρ = 0.81 g cm(-3) are investigated by carrying out Born-Oppenheimer molecular dynamics, and the electronic absorption spectrum in scCO2 is determined by time dependent density functional theory. The structure of the PNA-scCO2 solution illustrates the role played by Lewis acid-base (LA-LB) interactions. In comparison with isolated PNA, the ν(N-O) symmetric and asymmetric stretching modes of PNA in scCO2 are red-shifted by -17 and -29 cm(-1), respectively. The maximum of the charge transfer (CT) absorption band of PNA in scSCO2 is at 3.9 eV, and the predicted red-shift of the π → π* electronic transition relative to the isolated gas-phase PNA molecule reproduces the experimental value of -0.35 eV. An analysis of the relationship between geometry distortions and excitation energies of PNA in scCO2 shows that the π → π* CT transition is very sensitive to changes of the N-O bond distance, strongly indicating a correlation between vibrational and electronic solvatochromism driven by LA-LB interactions. Despite the importance of LA-LB interactions to explain the solvation of PNA in scCO2, the red-shift of the CT band is mainly determined by electrostatic interactions.

  12. Surface enhanced Raman scattering, electronic spectrum, natural bond orbital, and Mulliken charge distribution in the normal modes of diethyldithiocarbamate copper (II) complex, [Cu(DDTC)2].

    Science.gov (United States)

    Téllez Soto, C A; Costa, A C; Ramos, J M; Vieira, L S; Rost, N C V; Versiane, O; Rangel, J L; Mondragón, M A; Raniero, L; Martin, A A

    2013-12-01

    Surface-enhanced Raman scattering (SERS) was used to study the interactions of the normal modes of the diethyldithiocarbamate copper (II) complex, [Cu(DDTC)2] on nano-structured mixture silver-gold surfaces and on silver surfaces. The electronic spectrum of this complex was measured and the charge transfer bands were assigned through the TD-PBE1PBE procedure. Natural bond orbital (NBO) were also carried out to study the Cu(II) hybridation leading to the square planar geometry of the framework of the [Cu(DDTC)2] complex, and to study which are the donor NBO and the acceptor NBO in meaningful charge transfer through the Second Order Perturbation Theory Analysis of the Fox Matrix in NBO basis. To see the electronic dispersion, the Mulliken electronic charges (MAC) were calculated for each normal mode and correlated with the SERS effect. Full assignment of the SERS spectra was also supported by carefully analysis of the distorted geometries generated by the normal modes.

  13. Direct Conversion of Energy

    Energy Technology Data Exchange (ETDEWEB)

    Corliss, William R

    1964-01-01

    Topics include: direct versus dynamic energy conversion; laws governing energy conversion; thermoelectricity; thermionic conversion; magnetohydrodynamic conversion; chemical batteries; the fuel cell; solar cells; nuclear batteries; and advanced concepts including ferroelectric conversion and thermomagnetic conversion.

  14. Electron and Photon ID

    CERN Document Server

    Hryn'ova, Tetiana; The ATLAS collaboration

    2017-01-01

    The identification of prompt photons and the rejection of background coming mostly from photons from hadron decays relies on the high granularity of the ATLAS calorimeter. The electron identification used in ATLAS for run 2 is based on a likelihood discrimination to separate isolated electron candidates from candidates originating from photon conversions, hadron misidentification and heavy flavor decays. In addition, isolation variables are used as further handles to separate signal and background. Several methods are used to measure with data the efficiency of the photon identification requirements, to cover a broad energy spectrum. At low energy, photons from radiative Z decays are used. In the medium energy range, similarities between electrons and photon showers are exploited using Z->ee decays. At high energy, inclusive photon samples are used. The measurement of the efficiencies of the electron identification and isolation cuts are performed with the data using tag and probe techniques with large statis...

  15. Effect of electron transport properties on unipolar CdZnTe radiation detectors: LUND, SpectrumPlus, and Coplanar Grid

    Energy Technology Data Exchange (ETDEWEB)

    Ralph B. James

    2000-01-07

    Device simulations of (1) the laterally-contacted-unipolar-nuclear detector (LUND), (2) the SpectrumPlus, (3) and the coplanar grid made of Cd{sub 0.9}Zn{sub 0.1}Te (CZT) were performed for {sup 137}Cs irradiation by 662.15 keV gamma-rays. Realistic and controlled simulations of the gamma-ray interactions with the CZT material were done using the MCNP4B2 Monte Carlo program, and the detector responses were simulated using the Sandia three-dimensional multielectrode simulation program (SandTMSP). The simulations were done for the best and the worst expected carrier nobilities and lifetimes of currently commercially available CZT materials for radiation detector applications. For the simulated unipolar devices, the active device volumes were relatively large and the energy resolutions were fairly good, but these performance characteristics were found to be very sensitive to the materials properties. The internal electric fields, the weighting potentials, and the charge induced efficiency maps were calculated to give insights into the operation of these devices.

  16. Comparison of noise power spectrum methodologies in measurements by using various electronic portal imaging devices in radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Son, Soon Yong [Dept. of Radiological Technology, Wonkwang Health Science University, Iksan (Korea, Republic of); Choi, Kwan Woo [Dept. of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Jeong, Hoi Woun [Dept. of Radiological Technology, Baekseok Culture University College, Cheonan (Korea, Republic of); Kwon, Kyung Tae [Dep. of Radiological Technology, Dongnam Health University, Suwon (Korea, Republic of); Kim, Ki Won [Dept. of Radiology, Kyung Hee University Hospital at Gang-dong, Seoul (Korea, Republic of); Lee, Young Ah; Son, Jin Hyun; Min, Jung Whan [Shingu University College, Sungnam (Korea, Republic of)

    2016-03-15

    The noise power spectrum (NPS) is one of the most general methods for measuring the noise amplitude and the quality of an image acquired from a uniform radiation field. The purpose of this study was to compare different NPS methodologies by using megavoltage X-ray energies. The NPS evaluation methods in diagnostic radiation were applied to therapy using the International Electro-technical Commission standard (IEC 62220-1). Various radiation therapy (RT) devices such as TrueBeamTM(Varian), BEAMVIEWPLUS(Siemens), iViewGT(Elekta) and ClinacR iX (Varian) were used. In order to measure the region of interest (ROI) of the NPS, we used the following four factors: the overlapping impact, the non-overlapping impact, the flatness and penumbra. As for NPS results, iViewGT(Elekta) had the higher amplitude of noise, compared to BEAMVIEWPLUS (Siemens), TrueBeamTM(Varian) flattening filter, ClinacRiXaS1000(Varian) and TrueBeamTM(Varian) flattening filter free. The present study revealed that various factors could be employed to produce megavoltage imaging (MVI) of the NPS and as a baseline standard for NPS methodologies control in MVI.

  17. Efficiency Calibration of a Mini-Orange Type beta-Spectrometer by the $\\beta^{-}$-Spectrum of $^{90}$Sr

    CERN Document Server

    Kalinnikov, V G; Solnyshkin, A A; Sereeter, Z; Lebedev, N A; Chumin, V G; Ibrakhin, Ya S

    2002-01-01

    A specific method for efficiency calibration of a mini-orange type beta-spectrometer by means of the continuous beta^{-}-spectrum of ^{90}Sr and the conversion electron spectrum of ^{207}Bi in the energy range from 500 to 2200 keV has been elaborated. In the experiment typical SmCo_5 magnets (6A and 8A) were used. An accuracy of efficiency determination was 5-10 %.

  18. Atlas and wavenumber tables for the visible part of the electronic-vibro-rotational D2 spectrum emitted by low-temperature plasma

    Science.gov (United States)

    Lavrov, Boris P.; Umrikhin, Ivan S.

    2016-10-01

    The visible part (≈ 419-696 nm) of the multiline electronic-vibro-rotational (rovibronic) emission spectrum of the D2 molecule was recorded with a moderate resolution mainly determined by Doppler broadening of spectral lines (the observed line widths are equal to 0.0122(4) nm throughout the wavelength range under study). After the numerical deconvolution of the recorded intensity distributions and proper spectrometer calibrations, the new set of wavenumber values for rovibronic spectral lines has been obtained. It is shown that these new data are significantly more precise than experimental wavenumber values currently published for the visible part of the D2 spectrum, except for the fragmentary results of our high-resolution experiments (Phys. Rev. A, 2012). The assignments of the triplet rovibronic lines are verified by means of the optimizational technique based on two general principles: Rydberg-Ritz and maximum likelihood (J. Phys. B, 2008). Final results (reported in the on-line supplement material) include an atlas and accompanying tables. The atlas is divided into 158 sections (each section covers about 1.5 nm) containing images of the focal plane of the spectrometer and intensity distributions in linear and logarithmic scales. The tables contain wavenumber and relative intensity values for 11 941 spectral lines together with the available and new line assignments for the D2 and HD molecules.

  19. Origin of fine oscillations in the photoluminescence spectrum of 2-dimensional electron gas formed in AlGaN/GaN high electron mobility transistor structures

    Energy Technology Data Exchange (ETDEWEB)

    Jana, Dipankar, E-mail: dip2602@gmail.com; Porwal, S.; Oak, S. M.; Sharma, T. K., E-mail: tarun@rrcat.gov.in [Semiconductor Physics and Devices Laboratory, Raja Ramanna Centre for Advanced Technology, Indore 452013, Madhya Pradesh (India); Jain, Anubha [Solid State Physics Laboratory, Lucknow Road, New Delhi 110054 (India)

    2015-10-28

    An unambiguous identification of the fine oscillations observed in the low temperature photoluminescence (PL) spectra of AlGaN/GaN based high electron mobility transistor (HEMT) structures is carried out. In literature, such oscillations have been erroneously identified as the sub-levels of 2-dimensional electron gas (2DEG) formed at AlGaN/GaN heterointerface. Here, the origin of these oscillations is probed by performing the angle dependent PL and reflectivity measurements under identical conditions. Contrary to the reports available in literature, we find that the fine oscillations are not related to 2DEG sub-levels. The optical characteristics of these oscillations are mainly governed by an interference phenomenon. In particular, peculiar temperature dependent redshift and excitation intensity dependent blueshift, which have been interpreted as the characteristics of 2DEG sub-levels in HEMT structures by other researchers, are understood by invoking the wavelength and temperature dependence of the refractive index of GaN within the framework of interference phenomenon. The results of other researchers are also consistently explained by considering the fine oscillatory features as the interference oscillations.

  20. Engineered Solution-Liquid-Solid Growth of a "Treelike" 1D/1D TiO2 Nanotube-CdSe Nanowire Heterostructure: Photoelectrochemical Conversion of Broad Spectrum of Solar Energy.

    Science.gov (United States)

    Mukherjee, Bratindranath; Sarker, Swagotom; Crone, Eric; Pathak, Pawan; Subramanian, Vaidyanathan R

    2016-12-07

    This work presents a hitherto unreported approach to assemble a 1D oxide-1D chalcogenide heterostructured photoactive film. As a representative system, bismuth (Bi) catalyzed 1D CdSe nanowires are directly grown on anodized 1D TiO2 nanotube (T_NT). A combination of the reductive successive-ionic-layer-adsorption-reaction (R-SILAR) and the solution-liquid-solid (S-L-S) approach is implemented to fabricate this heterostructured assembly, reported in this 1D/1D form for the first time. XRD, SEM, HRTEM, and elemental mapping are performed to systematically characterize the deposition of bismuth on T_NT and the growth of CdSe nanowires leading to the evolution of the 1D/1D heterostructure. The resulting "treelike" photoactive architecture demonstrates UV-visible light-driven electron-hole pair generation. The photoelectrochemical results highlight: (i) the formation of a stable n-n heterojunction between TiO2 nanotube and CdSe nanowire, (ii) an excellent correlation between the absorbance vis-à-vis light conversion efficiency (IPCE), and (iii) a photocurrent density of 3.84 mA/cm(2). This proof-of-concept features the viability of the approach for designing such complex 1D/1D oxide-chalcogenide heterostructures that can be of interest to photovoltaics, photocatalysis, environmental remediation, and sensing.

  1. Widespread atypical vascular lesions of the skin after whole-body electron beam therapy: expanding the clinical spectrum.

    Science.gov (United States)

    Sinclair, Werner

    2013-02-01

    Atypical vascular lesion of the skin is an uncommon usually benign condition, thus far reported almost exclusively from mammary skin after radiotherapy for carcinoma of the breast. Some clinical and histological overlap exists with early angiosarcoma, which can also occur on irradiated skin. The lesions are divided into vascular and lymphatic types, the first representing a higher risk for development of angiosarcoma and the latter being more common. This article reports a rare case of widespread, progressive, vascular-type atypical vascular lesion after repeated whole-body electron beam irradiation administered as treatment for mycosis fungoides.

  2. The S1 ← S0 fluorescence excitation spectrum and structure of propanal in the S1 excited electronic state.

    Science.gov (United States)

    Godunov, I A; Yakovlev, N N; Terentiev, R V; Maslov, D V; Abramenkov, A V

    2016-06-01

    We have obtained and analyzed the S1 ← S0 fluorescence excitation spectra of jet-cooled propanal-h1 (CH3CH2CHO) and -d1 (CH3CH2CDO). Using the results of theoretical studies of the structure of propanal molecule in the S1 lowest excited singlet electronic state, we have assigned the bands of both spectra to the vibronic transitions of the cis conformer (in the S0 ground electronic state) to the 1 and 3 conformers (in the S1 state) differed by the angle of the C2H5 ethyl group rotation around the central C-C bond. The origins of the 1 ← cis and 3 ← cis electronic transitions have been observed at 29 997 and 30 075 cm(-1) for propanal-h1 and at 30 040 and 30 115 cm(-1) for propanal-d1, respectively. The high activity of torsional (C2H5 ethyl groups) and inversional (CCHO/CCDO carbonyl fragments) vibrations and the intensity distribution of the bands in torsional sequences (passing through maximum) are in agreement with the theoretical prediction that the S1 ← S0 electronic excitation of the cis conformer causes (after geometrical relaxation) the pyramidalization of carbonyl fragments and the rotation of ethyl groups around the central C-C bond. A number of energy levels have been found for torsional and inversional vibrations, and also fundamentals of ν10 (CCO bend) and ν13 (CCC bend) for the both 1 and 3 conformers of propanal-h1 and -d1 have been found. Then the "experimental" potential functions of inversion for the pair of the 1 and 3 conformers have been determined. The heights of potential barriers to inversion and the angle values corresponding to the minima of potential functions of inversion are 900 cm(-1) and 35° for propanal-h1 and 820 cm(-1) and 34° for propanal-d1, respectively.

  3. The Extraction of the Invariant Mass Spectrum From the Electron-Deuteron Scattering by Inclusive Analysis of the BLAST Data

    Directory of Open Access Journals (Sweden)

    Barış Tamer Tonguç

    2011-06-01

    Full Text Available Data from scattering polarized electrons, linearly accelerated up to 850 MeV energy, off polarized hydrogen and deuterium targets have been collected with BLAST Spectrometer at Bates Laboratory of Massachusetts Institute of Technology (MIT between 2003 and 2005. Among these data, the analysis of the electron-deuteron scattering part of the data for the measurement of the double spin asymmetry via pion photo-electro production technique has begun recently. Here, we present four momentum transfer square (Q2 and the invariant mass (W spectra, and its dependence to Q2 as the initial results of the analysis. It was seen that the results satisfied the theoretical expectations. In addition, due to the necessity that the later analysis will be done in the resonance region, it was understood that the condition of W of the scattering being above 1.1 GeV/c2 has to be met for the isolation of the region from the non resonant one.

  4. X-ray fluorescence spectrum of highly charged Fe ions driven by strong free-electron-laser fields

    CERN Document Server

    Oreshkina, Natalia S; Keitel, Christoph H; Harman, Zoltán

    2015-01-01

    The influence of nonlinear dynamical effects is analyzed on the observed spectra of controversial 3C and 3D astrophysically relevant x-ray lines in neonlike Fe${}^{16+}$ and the A, B, C lines in natriumlike Fe${}^{15+}$ ions. First, a large-scale configuration-interaction calculation of oscillator strengths is performed with the inclusion of higher-order electron-correlation effects. Also, quantum-electrodynamic corrections to the transition energies are calculated. Further considered dynamical effects provide a possible resolution of the discrepancy between theory and experiment found by recent x-ray free-electron-laser measurements of these controversial lines. We find that, for strong x-ray sources, the modeling of the spectral lines by a peak with an area proportional to the oscillator strength is not sufficient and nonlinear dynamical effects have to be taken into account. Thus, we advocate the use of light-matter-interaction models also valid for strong light fields in the analysis and interpretation of...

  5. The clinicopathologic spectrum of putative extrarenal rhabdoid tumors. An analysis of 42 cases studied with immunohistochemistry or electron microscopy.

    Science.gov (United States)

    Parham, D M; Weeks, D A; Beckwith, J B

    1994-10-01

    The existence of extrarenal rhabdoid tumor (ERRT) as a discrete pathologic entity has been controversial despite frequent reports of its occurrence. We performed immunohistochemistry, electron microscopy, or both on 42 cases with this diagnosis sent in consultation to us. Only 12 of the 42 neoplasms had the histological findings of "classic" malignant rhabdoid tumor of the kidney; the remainder displayed a variety of neural, epithelial, myoid, mesenchymal, or ependymal patterns. Electron microscopy also showed that most possessed neural, epithelial, or ependymal features. Immunohistochemistry generally revealed marked polyphenotypia, with immunoreactivity to a wide array of antibodies against neural, epithelial, glial, and myogenic markers. A specific tissue-based diagnostic category could not be assigned in only 11 of the 42 cases, seven of which lacked material for a comprehensive ultrastructural or immunohistochemical study. We conclude that tumors currently diagnosed as ERRT represent a heterogeneous group of neoplasms that may form unique subsets of known entities within the specific site where they arise or that may defy classification into a specific alternative category. Our findings lead us to believe that the term ERRT is not valid as representing a specific diagnostic entity and to prefer the term "poorly differentiated neoplasm with rhabdoid features" for undifferentiated tumors.

  6. Conversational Telugu.

    Science.gov (United States)

    Beinstein, Judith; And Others

    The purpose of this text is to develop elementary conversational skills in Telugu. The language materials consist of four types of language learning activities. The first, and most predominant, is the unit microwave cycle. These cycles divide the learning process into two basic phases, the first of which involves mimicry, memorization, and…

  7. Conversion Disorder

    National Research Council Canada - National Science Library

    Fisher, Robert S; Stonnington, Cynthia M; Barry, John J

    2006-01-01

    ... to proceed after establishing a diagnosis of conversion disorder. Case Presentation "Ms. A," a 53-year-old left-handed woman, was admitted to our epilepsy monitoring unit for evaluation of a 4-month history of tremors, head bobbing, and episodic loss of awareness. The onset of these symptoms was 1 week after she had visited an emergency department...

  8. Quantum Chemical Study of the Low-Lying Electronic States of VSi3(-/0) Clusters and Interpretation of the Anion Photoelectron Spectrum.

    Science.gov (United States)

    Tran, Van Tan; Tran, Quoc Tri

    2016-07-28

    The geometrical and electronic structures of VSi3(-/0) clusters have been investigated with the DFT, CCSD(T), and CASSCF/CASPT2 methods. The results showed that the suitable functional to identify the ground states of VSi3(-/0) clusters is not the B3LYP but the BP86. At the BP86, CCSD(T), and CASPT2 levels, the ground state of the anionic cluster was the (1)A' ((1)A1) of tetrahedral η(3)-(Si3)V(-) isomer, while that of the neutral cluster was the 1(2)A' and 1(2)A″ (1(2)E) of the same isomer. The 1(2)A' and 1(2)A″ of the tetrahedral η(3)-(Si3)V isomer were the results of the Jahn-Teller distortions of the 1(2)E in C3v symmetry. All three bands in the photoelectron spectrum of the VSi3(-) cluster were interpreted by one-electron detachments from the (1)A' anionic ground state on the basis of the BP86, CCSD(T), and CASPT2 methods. The calculated adiabatic and vertical detachment energies were in agreement with the experimental values. The broad shape of the first band was explained by Franck-Condon factor simulations for the (1)A' → 1(2)A' and (1)A' → 1(2)A″ transitions within the tetrahedral η(3)-(Si3)V(-/0) isomers.

  9. Comparison of horizontal and vertical noise power spectrum in measurements by using various electronic portal imaging devices in radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Won [Dept. of Radiology, Kyung Hee University Hospital at Gang-dong, Seoul (Korea, Republic of); Choi, Kwan Woo [Dept. of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Jeong, Hoi Woun [Dept. of Radiological Technology, Baekseok Culture University, Cheonan (Korea, Republic of); Jang, Seo Goo [Dept. of Medical Science, Soonchunhyang University, Asan (Korea, Republic of); Kwon, Kyung Tae [Dept. of Radiological Technology, Dongnam Health University, Suwon (Korea, Republic of); Son, Soon Yong [Dept. of Radiological Technology, Wonkwang Health Science University, Iksan (Korea, Republic of); Son, Jin Hyun; Min, Jung Whan [Dept. of Radiological Technology, Shingu University, Sungnam (Korea, Republic of)

    2016-06-15

    The quality assurance (QA) is very important for diagnostic field and radiation therapy field to evaluate the characteristic of devices. The purpose of this study was to compare different NPS methodologies results which are measuring NPS with regard to horizontal and vertical directions by using megavoltage X-ray energies. The NPS evaluation methods were applied to the International Electro-technical Commission standard (IEC 62220-1). The electronic portal imaging devices (EPID) devices such as Siemens BEAMVIEWPLUS, Elekta iViewGT and Varian ClinacR iX aS1000 were used. NPS data were expressed by corresponding each frequency about average of noise value corresponding the each frequency, and NPS were evaluated quantitatively by totaling up the noise values of average frequency which are on horizontal and vertical directions. In NPS results for Elekta iViewGT, NPS of horizontal and vertical by using 4 methods were indicated the difference of 3-5% between horizontal and vertical direction. In the results of Siemens BEAMVIEWPLUS and Varian ClinacR iX aS1000, the NPS of horizontal and vertical direction were indicated the difference of 15% when averaging the whole values. This study were evaluated the NPS of each devices by totaling up the noise values of average frequency which are on horizontal and vertical directions suggesting the quantitative evaluation method using the data.

  10. The high-spin {sup 178m2}Hf isomer: production, chemical and isotopic separations, gamma spectrometry and internal conversion electrons spectrometry; L`isomere de haut spin {sup 178m2}Hf: production, separations chimiques et isotopiques, spectrometrie gamma et spectrometrie d`electrons de conversion interne

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.B.

    1993-10-13

    The high-spin isometric state of the nucleus 178Hf is a challenge for new and exotic nuclear physics studies. With its long half-life of 31 years, the production of a reasonable micro-weight quantity, with an isometric to ground state ratio as high as 5 per cent, is now regularly performed by intensive irradiations of ytterbium targets with helium ions of 36 MeV. Using sur-enriched, at 99,998 per cent, ytterbium 176 that we have prepared at the PARIS mass separator, the isomer purity has been improved. Targets of such material but also of enriched stable isotopes of hafnium have been prepared by electro-spraying of methanolic and acetic solutions. By inelastic diffusion of protons and deuton on these targets, the energy of the first state of the rotation band built on the isomer has been measured. Isotopic separations of the isomer have been performed, with a yield greater than 20 per cent, by the use of isotopically pure hafnium 176 as carrier. The separated beam of the mass 178 allowed to record the complete hyperfine spectrum of the isomer and to measure, for the first time, the magnetic dipole moment and the electric quadrupole moment. Isomer targets, implanted in various materials like copper, iron and hafnium monocrystal, provide the opportunity to accurately measure gamma and internal conversion decay of this nuclei and so to precise the multipolarity mixing of all transitions from K=16{sup +} to K=8{sup -}. (author). 49 refs., 47 figs., 11 tabs.

  11. Conversion Disorder

    Directory of Open Access Journals (Sweden)

    Yacov Rofé

    2013-11-01

    Full Text Available Conversion disorder remains a mystery that has only become more complicated with the decline of the scientific status of psychoanalysis (e.g., Piper, Lillevik, & Kritzer, 2008; Rofé, 2008 and recent neurological findings suggest that this behavior is controlled by biological mechanisms (van Beilen, Vogt, & Leenders, 2010. Moreover, existing theories have difficulty explaining the efficacy of various interventions, such as psychoanalysis, behavior therapy, drug therapy and religious therapy. This article reviews research and clinical evidence pertaining to both the development and treatment of conversion disorder and shows that this seemingly incompatible evidence can be integrated within a new theory, the Rational-Choice Theory of Neurosis (RCTN; Rofé, 2010. Despite the striking differences, RCTN continues Freud's framework of thinking as it employs a new concept of repression and replaces the unconscious with self-deception. Moreover, it incorporates Freud's idea, implicitly expressed in his theory, that neurotic disorders are, in fact, rational behaviors.

  12. Conversational sensing

    Science.gov (United States)

    Preece, Alun; Gwilliams, Chris; Parizas, Christos; Pizzocaro, Diego; Bakdash, Jonathan Z.; Braines, Dave

    2014-05-01

    Recent developments in sensing technologies, mobile devices and context-aware user interfaces have made it pos- sible to represent information fusion and situational awareness for Intelligence, Surveillance and Reconnaissance (ISR) activities as a conversational process among actors at or near the tactical edges of a network. Motivated by use cases in the domain of Company Intelligence Support Team (CoIST) tasks, this paper presents an approach to information collection, fusion and sense-making based on the use of natural language (NL) and controlled nat- ural language (CNL) to support richer forms of human-machine interaction. The approach uses a conversational protocol to facilitate a ow of collaborative messages from NL to CNL and back again in support of interactions such as: turning eyewitness reports from human observers into actionable information (from both soldier and civilian sources); fusing information from humans and physical sensors (with associated quality metadata); and assisting human analysts to make the best use of available sensing assets in an area of interest (governed by man- agement and security policies). CNL is used as a common formal knowledge representation for both machine and human agents to support reasoning, semantic information fusion and generation of rationale for inferences, in ways that remain transparent to human users. Examples are provided of various alternative styles for user feedback, including NL, CNL and graphical feedback. A pilot experiment with human subjects shows that a prototype conversational agent is able to gather usable CNL information from untrained human subjects.

  13. An unambiguous identification of 2D electron gas features in the photoluminescence spectrum of AlGaN/GaN heterostructures

    Science.gov (United States)

    Jana, Dipankar; Sharma, T. K.

    2016-07-01

    A fast and non-destructive method for probing the true signatures of 2D electron gas (2DEG) states in AlGaN/GaN heterostructures is presented. Two broad features superimposed with interference oscillations are observed in the low temperature photoluminescence (PL) spectrum. The two features are identified as the ground and excited 2DEG states which are confirmed by comparing the PL spectra of as-grown and top barrier layer etched samples. Broad PL features disappear at a certain temperature along with the associated interference oscillations. Furthermore, the two broad PL features depicts specific temperature and excitation intensity dependencies which make them easily distinguishable from the bandedge excitonic or defect related PL features. The presence of strong interference oscillations associated with the 2DEG PL features is explained by considering the localized generation of PL signal at the AlGaN/GaN heterointerface. Finally, a large value of the polarization induced electric field of ~1.01 MV cm-1 is reported from PL measurements for AlGaN/GaN HEMT structures. It became possible only when the true identification of 2DEG features was made possible by the proposed method.

  14. Composition and Performance of Nanostructured Zirconium Titanium Conversion Coating on Aluminum-Magnesium Alloys

    Directory of Open Access Journals (Sweden)

    Sheng-xue Yu

    2013-01-01

    Full Text Available Nanostructured conversion coating of Al-Mg alloy was obtained via the surface treatment with zirconium titanium salt solution at 25°C for 10 min. The zirconium titanium salt solution is composed of tannic acid 1.00 g·L−1, K2ZrF6 0.75 g·L−1, NaF 1.25 g·L−1, MgSO4 1.0 g/L, and tetra-n-butyl titanate (TBT 0.08 g·L−1. X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, and Fourier transform infrared spectrum (FT-IR were used to characterize the composition and structure of the obtained conversion coating. The morphology of the conversion coating was obtained by atomic force microscopy (AFM and scanning electron microscopy (SEM. Results exhibit that the zirconium titanium salt conversion coating of Al-Mg alloy contains Ti, Zr, Al, F, O, Mg, C, Na, and so on. The conversion coating with nm level thickness is smooth, uniform, and compact. Corrosion resistance of conversion coating was evaluated in the 3.5 wt.% NaCl electrolyte through polarization curves and electrochemical impedance spectrum (EIS. Self-corrosion current density on the nanostructured conversion coating of Al-Mg alloy is 9.7×10-8A·cm-2, which is only 2% of that on the untreated aluminum-magnesium alloy. This result indicates that the corrosion resistance of the conversion coating is improved markedly after chemical conversion treatment.

  15. Efficiency calibration of a mini-orange type beta-spectrometer by the beta sup - -spectrum of sup 9 sup 0 Sr

    CERN Document Server

    Kalinnikov, V G; Ibrakhim, Y S; Lebedev, N A; Samatov, Z K; Sehrehehtehr, Z; Solnyshkin, A A

    2002-01-01

    A specific method for efficiency calibration of a mini-orange type beta-spectrometer by means of the continuous beta sup - -spectrum of sup 9 sup 0 Sr and the conversion electron spectrum of sup 2 sup 0 sup 7 Bi in the energy range from 500 to 2200 keV has been elaborated. In the experiment typical SmCo sub 5 magnets (6A and 8A) were used. An accuracy of efficiency determination was 5-10 %.

  16. Spectrum and network measurements

    CERN Document Server

    Witte, Robert A

    2014-01-01

    This new edition of Spectrum and Network Measurements enables readers to understand the basic theory, relate it to measured results, and apply it when creating new designs. This comprehensive treatment of frequency domain measurements successfully consolidates all the pertinent theory into one text. It covers the theory and practice of spectrum and network measurements in electronic systems. It also provides thorough coverage of Fourier analysis, transmission lines, intermodulation distortion, signal-to-noise ratio and S-parameters.

  17. Novel Nuclear Powered Photocatalytic Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    White,John R.; Kinsmen,Douglas; Regan,Thomas M.; Bobek,Leo M.

    2005-08-29

    The University of Massachusetts Lowell Radiation Laboratory (UMLRL) is involved in a comprehensive project to investigate a unique radiation sensing and energy conversion technology with applications for in-situ monitoring of spent nuclear fuel (SNF) during cask transport and storage. The technology makes use of the gamma photons emitted from the SNF as an inherent power source for driving a GPS-class transceiver that has the ability to verify the position and contents of the SNF cask. The power conversion process, which converts the gamma photon energy into electrical power, is based on a variation of the successful dye-sensitized solar cell (DSSC) design developed by Konarka Technologies, Inc. (KTI). In particular, the focus of the current research is to make direct use of the high-energy gamma photons emitted from SNF, coupled with a scintillator material to convert some of the incident gamma photons into photons having wavelengths within the visible region of the electromagnetic spectrum. The high-energy gammas from the SNF will generate some power directly via Compton scattering and the photoelectric effect, and the generated visible photons output from the scintillator material can also be converted to electrical power in a manner similar to that of a standard solar cell. Upon successful implementation of an energy conversion device based on this new gammavoltaic principle, this inherent power source could then be utilized within SNF storage casks to drive a tamper-proof, low-power, electronic detection/security monitoring system for the spent fuel. The current project has addressed several aspects associated with this new energy conversion concept, including the development of a base conceptual design for an inherent gamma-induced power conversion unit for SNF monitoring, the characterization of the radiation environment that can be expected within a typical SNF storage system, the initial evaluation of Konarka's base solar cell design, the design and

  18. Development of an electronic ballast with high power factor, using cd/cd conversion techniques for fluorescent lamps; Desarrollo de un balastro electronico con alto factor de potencia, utilizando tecnicas de conversion cd/cd para lamparas fluorescentes

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, Raul Antonio

    1995-02-01

    The recent advances and improvements in fluorescent lamps and ballasts technologies have resulted in substantial gain in efficiency, in illumination (lm/w), in the useful life of the lamp, in ballasts (electric characteristics), and consequently, an increase in energy saving in the fluorescent illumination systems. This thesis work was for the development of an electronic ballast that incorporates active correction of the PF for the handling of fluorescent lamps of the fast start type F4OW T-12. The prototype was implemented in two stages. In the first stage, for the Power Factor Correction (PFC) a converter CD/CD of the boost type in Continuous Conduction Mode (CCM) was chosen. The control technique that was used for this converter was the Average Current Mode (ACM) control. This thesis work comprised part of a collaboration project between the Electronics Department of the Instituto de Investigaciones Electricas (IIE) and the Centro Nacional de Investigacion y Desarrollo Tecnologico (National Center of Investigation and Technological Development (CENIDET)) named Technology Assimilation of the Power Factor Correction in the Electronic Equipment Design. In chapter 1 of this thesis the advantages of fluorescent illumination systems (IS) are mentioned, with respect to the traditional incandescent illumination systems. Also the most important characteristics of the fluorescent lamps and the operation (physical) principle will be presented, as well as the design aspects of electronic ballasts and their evolution. The proposal of the development of an experimental electronic prototype of ballast will be set forth. Chapter 2 mentions the evolution of the different schemes of fluorescent lamps ballasts, of electromagnetic, as well as electronic. Also some of the specifications that were taken into consideration for the design of the electronic prototype of the ballast presented in this thesis are mentioned. In chapter 3 the specifications of the electronic prototype of

  19. Power conversion technologies

    Energy Technology Data Exchange (ETDEWEB)

    Newton, M. A.

    1997-02-01

    The Power Conversion Technologies thrust area identifies and sponsors development activities that enhance the capabilities of engineering at Lawrence Livermore National Laboratory (LLNL) in the area of solid- state power electronics. Our primary objective is to be a resource to existing and emerging LLNL programs that require advanced solid-state power electronic technologies.. Our focus is on developing and integrating technologies that will significantly impact the capability, size, cost, and reliability of future power electronic systems. During FY-96, we concentrated our research efforts on the areas of (1) Micropower Impulse Radar (MIR); (2) novel solid-state opening switches; (3) advanced modulator technology for accelerators; (4) compact accelerators; and (5) compact pulse generators.

  20. The infrared spectrum of spessartine Mn3Al2Si3O12 : An ab initio all electron simulation with five different functionals (LDA, PBE, PBESOL, B3LYP and PBE0)

    Science.gov (United States)

    Maschio, L.; Ferrabone, M.; Meyer, A.; Garza, J.; Dovesi, R.

    2011-01-01

    The performance of five different density functionals (LDA, PBE, PBESOL, B3LYP and PBE0) in describing the infrared spectrum of a crystalline periodic system with a large unit cell (spessartine, 80 atoms in the primitive cell) is studied by using the periodic ab initio CRYSTAL09 code and an all electron basis set. The transverse (TO) and longitudinal (LO) optical branches of the 17 IR active modes are evaluated together with the oscillator strengths and the high frequency dielectric tensor ɛ∞ . These ingredients permit to compute the dielectric function ɛ (ν) , and then the reflectance spectrum R (ν) , which is compared with experiment.

  1. Simultaneous spectroscopy of $\\gamma$- rays and conversion electrons: Systematic study of EO transitions and intruder states in close vicinity of mid-shell point in odd-Au isotopes

    CERN Multimedia

    Venhart, M; Grant, A F; Petrik, K

    This proposal focuses on detailed systematic studies of the $\\beta$ /EC-decays of $^{179,181,183,185}$Hg leading to excited states in the neutron-deficient Au isotopes in the vicinity of the N=104 midshell. $\\gamma$-ray, X-ray and conversion electron de-excitations of odd-A Au isotopes will be studied simultaneously. These studies will address important structural questions such as the excitation energies of coexisting states, properties of multiple intruder states (i.e. intruder particles coupled to intruder cores) and mixing of coexisting structures. The unique combination of Hg beam purity and yields make ISOLDE a unique facility for these experiments.

  2. Towards broad range and highly efficient down-conversion of solar spectrum by Er{sup 3+}-Yb{sup 3+} co-doped nano-structured glass-ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, V.D.; Mendez-Ramos, J. [Departamento de Fisica Fundamental y Experimental, Electronica y Sistemas, Universidad de La Laguna, E-38206 La Laguna, Tenerife (Spain); Tikhomirov, V.K.; Moshchalkov, V.V. [INPAC-Institute for Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven (Belgium); Yanes, A.C. [Departamento de Fisica Basica, Universidad de La Laguna, E-38206 La Laguna, Tenerife (Spain)

    2010-10-15

    The efficiency of semiconductor solar cells could be greatly increased by down-conversion processes, which efficiently split incident solar photons into couples of photons with energy over the bandgap. Here, we show new down-conversion mechanisms in Er{sup 3+}-Yb{sup 3+} co-doped glass-ceramics, where the ions are hosted by fluoride nanoparticles embedded in silica glass. By this means, 350-550 nm photons, absorbed by Er{sup 3+} ions, generate pairs of photons at the range of 650-1550 nm, emitted by Er{sup 3+} and Yb{sup 3+}, with a quantum efficiency approaching the maximum of 200%. (author)

  3. Teaching Children with Autism to Respond to Conversation Partners' Interest

    Science.gov (United States)

    Peters, Lindsay C.; Thompson, Rachel H.

    2015-01-01

    Successful conversation requires that the speaker's behavior is sensitive to nonvocal listener responses. We observed children with autism spectrum disorder during conversation probes in which a listener periodically displayed nonvocal cues that she was uninterested in the conversation. We used behavioral skills training to teach conversation…

  4. Plasmonic Nanomaterials for Optical-to-Electrical Energy Conversion

    Science.gov (United States)

    Sheldon, Matthew

    High-quality semiconductor solids have been the dominant photovoltaic materials platform for decades. Although several alternative approaches have been proposed, e.g. dye-sensitized cells or polymeric solids, none compete in terms of cost and conversion efficiency, the crucial benchmarks for industrial scale implementation. However, semiconductors suffer from several fundamental limitations relating to the microscopic mechanism of power conversion that preclude them, even theoretically, from achieving conversion efficiency at the Carnot limit of 95%. Indeed, the fundamentally different tasks of semiconductors in photovoltaic devices, both as optical absorbers, and separately, for electron-hole pair separation and collection, often demand opposing trade-offs in materials optimization. Alternatively, recent advances in subwavelength metal optics, e.g. nanophotonics, metamaterials, and plasmonics, provide several new examples where nanostructured metals perform the separate tasks of absorption and charge separation necessary for photovoltaic power conversion. Nanostructured metals are extremely efficient broadband absorbers of radiation, with tailorable optical properties throughout the visible and infrared spectrum. It is traditionally assumed that the lack of a band gap and consequent fast electronic relaxation (fs) and short mean free path (100 nm) hinders efficient carrier collection. However, new phenomena resulting from the remarkable energy concentration and nanoscale collection geometry afforded by plasmonic systems suggest new strategies may be possible that use all metal structures. In this talk, I will describe two ongoing studies in our laboratory that exemplify opportunities for metal-based optical energy conversion: (1) Excitation with circularly polarized illumination can induce strong, persistent electrical drift currents in resonant metal nanostructures via the inverse faraday effect. (2) Plasmonic absorption in metal nanostructures provides an

  5. Cooperative internal conversion process

    CERN Document Server

    Kálmán, Péter

    2015-01-01

    A new phenomenon, called cooperative internal conversion process, in which the coupling of bound-free electron and neutron transitions due to the dipole term of their Coulomb interaction permits cooperation of two nuclei leading to neutron exchange if it is allowed by energy conservation, is discussed theoretically. General expression of the cross section of the process is reported in one particle nuclear and spherical shell models as well in the case of free atoms (e.g. noble gases). A half-life characteristic of the process is also determined. The case of $Ne$ is investigated numerically. The process may have significance in fields of nuclear waste disposal and nuclear energy production.

  6. Efficient energy storage and conversion using adiabatic compression of relativistic-electron plasmas. Final report for 15 May 1986-31 December 1988

    Energy Technology Data Exchange (ETDEWEB)

    Guest, G.E.; Dandl, R.A.; Miller, R.L.

    1989-01-17

    The Plasma Electron Microwave Source (PEMS) concept is a relativistic-electron plasma confined in a magnetic-mirror device. The stored energy is transformed into microwaves through amplification of whistler waves that can be launched externally for amplifier operation or generated spontaneously for oscillator operation. The anisotropy of the hot-electron temperature governs the maximum plasma energy density that can be stored, the amplification rates, and the saturated power level of the unstable whistler waves. This report summarizes the results of theoretical studies of (1) the critical aspects of hot-electron plasmas generated by ECH techniques, such as the Upper Off-Resonant Heating pioneered by Dandl in the ELMO series of experiments; and, (2) the spatial amplification rates of unstable whistler waves in these plasmas. It is shown that a substantial fraction of the energy stored in a hot-electron plasma can be transformed into repetitive pulses of microwave power by employing the PEMS approach, with typical values of gain, about 40db and bandwidth.

  7. Electron stimulated desorption of oxygen from, and subsequent type conversion of, thin-film p-CuInSe/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Matson, R.J.; Kazmerski, L.L.; Noufi, R.; Cahen, D.

    1989-03-01

    There are seemingly conflicting results from two sets of investigations in the literature concerning the electron stimulated desorption of oxygen incorporated into thin-film p-CuInSe/sub 2/ This has a direct bearing on the model for the role of oxygen in the important postdeposition oxygen treatment of CdS/CuInSe/sub 2/ solar cells, proposed in one of the published reports. By comparing the specific beam parameters of the scanning electron microscope (SEM)/ electron beam induced current (EBIC) versus scanning Auger microprobe (SAM) based studies and calculating charge density for the two cases, the SAM experiments are seen to support, rather than contradict, the results of the SEM/EBIC experiments. The evidence tying the addition and deletion of oxygen to changes in the electrical properties of the CuInSe/sub 2/ are then discussed.

  8. Two-electron photo-oxidation of betanin on titanium dioxide and potential for improved dye-sensitized solar energy conversion

    OpenAIRE

    Banerji, N.; Hayes, S. C.; Knorr, Fritz J.; Melamen, Deborah J.; Mchale, Jeanne L.; Marchioro, Arianna; Moser, Jacques-Edouard

    2014-01-01

    The plant pigment betanin is investigated as a dye-sensitizer on TiO2 with regard to its potential to undergo two- electron oxidation following one-photon excitation. Electrochemical, spectroelectrochemical and transient absorption measurements provide evidence for two-electron proton-coupled photo-oxidation leading to a quinone methide interme- diate which rearranges to 2-decarboxy-2,3-dehydrobetanin. Time-resolved spectroscopy measurements of betanin on nanocrystalline TiO2 and ZrO2 films w...

  9. Two-electron photo-oxidation of betanin on titanium dioxide and potential for improved dye-sensitized solar energy conversion

    OpenAIRE

    Knorr, Fritz J.; Malamen, Deborah J.; Mchale, Jeanne L.; Marchioro, Arianna; Moser, Jacques-Edouard

    2014-01-01

    The plant pigment betanin is investigated as a dye-sensitizer on TiO2 with regard to its potential to undergo two-electron oxidation following one-photon excitation. Electrochemical, spectroelectrochemical and transient absorption measurements provide evidence for two-electron proton-coupled photo-oxidation leading to a quinone methide intermediate which rearranges to 2-decarboxy-2,3-dehydrobetanin. Time-resolved spectroscopy measurements of betanin on nanocrystalline TiO2 and ZrO2 films were...

  10. Probing ultrafast \\pi\\pi*/n\\pi* internal conversion in organic chromophores via K-edge resonant absorption

    CERN Document Server

    Wolf, T J A; Cryan, J P; Coriani, S; Squibb, R J; Battistoni, A; Berrah, N; Bostedt, C; Bucksbaum, P; Coslovich, G; Feifel, R; Gaffney, K J; Grilj, J; Martinez, T J; Miyabe, S; Moeller, S P; Mucke, M; Natan, A; Obaid, R; Osipov, T; Plekan, O; Wang, S; Koch, H; Gühr, M

    2016-01-01

    Organic chromophores with heteroatoms possess an important excited state relaxation channel from an optically allowed {\\pi}{\\pi}* to a dark n{\\pi}*state. We exploit the element and site specificity of soft x-ray absorption spectroscopy to selectively follow the electronic change during the {\\pi}{\\pi}*/n{\\pi}* internal conversion. As a hole forms in the n orbital during {\\pi}{\\pi}*/n{\\pi}* internal conversion, the near edge x-ray absorption fine structure (NEXAFS) spectrum at the heteroatom K-edge exhibits an additional resonance. We demonstrate the concept with the nucleobase thymine, a prototypical heteroatomic chromophore. With the help of time resolved NEXAFS spectroscopy at the oxygen K-edge, we unambiguously show that {\\pi}{\\pi}*/n{\\pi}* internal conversion takes place within (60 \\pm 30) fs. High-level coupled cluster calculations on the isolated molecules used in the experiment confirm the superb electronic structure sensitivity of this new method for excited state investigations.

  11. Electron Bernstein Wave Emission from RFP Plasmas

    Science.gov (United States)

    Nornberg, M. D.; Thomas, M.; Anderson, J.; Forest, C. B.

    1998-11-01

    Electron cyclotron emission (ECE) has proven to be a powerfull diagnostic tool in tokamak plasmas for determining the time evolution of the electron temperature profile. The standard technique of observing O-mode or X-mode electromagnetic waves normal to the magnetic field is not applicable to reversed field pinch (RFP) plasmas since the plasma frequency is much larger than the electron cyclotron frequency. We are investigating the use of electron Bernstein waves (presumed to be in thermal equilibrium with the electrons) through the aip.org/journal_cgi/ getpdf?KEY=PRLTAO&cvips=PRLTAO000078000018003467000001>O-X-B mode conversion process. At oblique incidence, the evanescent layer separating the plamsa cutoff from the cyclotron cutoff vanishes, allowing conversion of the Bernstein mode waves to the extraordinary mode and finally to the ordinary mode. The O-mode radiation is received by a phased array antenna consisting of two waveguides on the edge of the plasma, and the spectrum of emitted radiation is measured using a radiometer spanning 4-8 GHz. In addition to providing information about the electron temperature profile, the spectrum can provide a novel method of measuring the central magnetic field strength for current profile reconstructions.

  12. Impulsive solar X-ray bursts. 4: Polarization, directivity and spectrum of the reflected and total bremsstrahlung radiation from a beam of electrons directed toward the photosphere

    Science.gov (United States)

    Langer, S. H.; Petrosian, V.

    1976-01-01

    A Monte Carlo method is described for evaluation of the spectrum, directivity and polarization of X-rays diffusely reflected from stellar photospheres. the accuracy of the technique is evaluated through comparison with analytic results. Using the characteristics of the incident X-rays of the model for solar X-ray flares, the spectrum, directivity and polarization of the reflected and the total X-ray fluxes are evaluated. The results are compared with observations.

  13. UV Filtering of Dye-Sensitized Solar Cells: The Effects of Varying the UV Cut-Off upon Cell Performance and Incident Photon-to-Electron Conversion Efficiency

    Directory of Open Access Journals (Sweden)

    Matthew Carnie

    2012-01-01

    Full Text Available With current technology, UV filters are essential to ensure long-term dye-sensitized solar cell (DSC stability. Blocking photons, however, will have an obvious effect on device performance and upon its incident photon-to-current conversion efficiency (IPCE. Filters have been applied to DSC devices with a range of cut-off wavelengths in order to assess how different levels of filtering affect the performance and IPCE of devices made with three different dyes, namely N719, Z907, and N749. It is shown that dyes that extend their IPCE further into the NIR region suffer lesser relative efficiency losses due to UV filtering than dyes with narrower action spectra. Furthermore, the results are encouraging to those working towards the industrialisation of DSC technology. From the results presented it can be estimated that filtering at a level intended to prevent direct band gap excitation of the TiO2 semiconductor should cause a relative drop in cell efficiency of no more than 10% in forward illuminated devices and no more than 2% in reverse illuminated devices.

  14. Mode characterization, autocorrelation measurements, and harmonic conversion with pico- and femtosecond pulses delivered by the Mark III free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Cutolo, A.; Hooper, B.; Benson, S.V.; Schultz, J.F.; Madeys, J.M.

    1989-01-01

    After briefly reporting on the present status of the infrared free-electron laser now operating at the Stanford Photon Research Laboratory and powered by the linear accelerator Mark III, we discuss the results of using nonlinear optical techniques for both the characterization of its output radiation and the enhancment of its tunability range. In particular, to show the evidence of possible self-guiding effects, a new and reliable technique has been devised and successfully tested for real-time monitoring of the micropulse evolution during the buildup of radiation. Finally, we discuss the main problems connected with the damage threshold of optical materials.

  15. 57Fe-ion implantation in pulse laser deposited La0.75Ca0.25MnO3 films: Conversion electron Mössbauer spectroscopy and X-ray diffraction studies

    Indian Academy of Sciences (India)

    U D Lanke; J Prabhjyot Pal

    2000-02-01

    Oriented La0.75Ca0.25MnO3 (LCMO) films have been deposited by pulsed laser deposition (PLD) method on (100) LaAlO3 substrates. Ion-beam technique is used to introduce a very low concentration of 57Fe+ in LCMO film. The deposited films were subjected to 100 keV 57Fe+ implantation with different fluences at room temperature. The main motivation of this work was to study the influence of implantation on the transport mechanism in materials exhibiting colossal magnetoresistance (CMR) property. It is observed that Fe implantation drastically affects the structural and magneto-transport properties. The samples were characterized using the X-ray diffraction (XRD) technique, conversion electron Mössbauer spectroscopy (CEMS) and resistance temperature (–) measurements.

  16. How is the water molecule activated on metalloporphyrins? Oxygenation of substrates induced through one-photon/two-electron conversion in artificial photosynthesis by visible light.

    Science.gov (United States)

    Shimada, Tetsuya; Kumagai, Akihiro; Funyu, Shigeaki; Takagi, Shinsuke; Masui, Dai; Nabetani, Yu; Tachibana, Hiroshi; Tryk, Donald A; Inoue, Haruo

    2012-01-01

    The reaction mechanism of the highly efficient (phi = 0.60), selective photochemical epoxidation of alkenes sensitized by CO-coordinated tetra(2,4,6-trimethyl)phenylporphyrinatoruthenium(II) (Ru(II)TMP(CO)), with water acting both as an electron and oxygen atom donor, was investigated. The steady-state light irradiation of the reaction mixture indicated the formation of the Ru(II)TMP (CO) cation radical under neutral conditions, which was effectively trapped by an hydroxide ion to regenerate the starting sensitizer. By means of a laser flash photolysis experiment, the formation of the cation radical as the primary process from the triplet excited state of Ru(II)TMP(CO) was clearly observed. Four kinds of transients were detected in completely different ranges of the delay time: the excited triplet state of Ru(II)TMP(CO) [delay time region reaction mechanism was revealed that involves RuTMP(CO) cation radical formation from the triplet excited state of the sensitizer, followed by attack of an hydroxide ion to form an hydroxyl-coordinated Ru-porphyrin (Intermediate [I]) and subsequent reaction with cyclohexene to form Intermediate [II]. The kinetics for each step of the successive processes was carefully analyzed and their rate constants were determined. The two-electron oxidation of water by one-photon irradiation, as revealed in the photochemical epoxidation, is proposed to be one of the more promising candidates to get through the bottleneck of water oxidation in artificial photosynthesis.

  17. Wavelength conversion devices and techniques

    DEFF Research Database (Denmark)

    Stubkjær, Kristian; Jørgensen, Carsten; Danielsen, Søren Lykke;

    1996-01-01

    Wavelength division multiplexed (WDM) networks are currently subject to an immense interest because of the extra capacity and flexibility they provide together with the possibilities for graceful system upgrades. For full network flexibility it is very attractive to be able to translate the chann...... wavelengths in an easy way and preferably without opto-electronic conversion. Here, we will first briefly look at advantages of employing optical wavelength converters in WDM networks and next review the optical wavelength conversion devices with emphasis on recent developments....

  18. Quantum Entanglement Molecular Absorption Spectrum Simulator

    Science.gov (United States)

    Nguyen, Quang-Viet; Kojima, Jun

    2006-01-01

    Quantum Entanglement Molecular Absorption Spectrum Simulator (QE-MASS) is a computer program for simulating two photon molecular-absorption spectroscopy using quantum-entangled photons. More specifically, QE-MASS simulates the molecular absorption of two quantum-entangled photons generated by the spontaneous parametric down-conversion (SPDC) of a fixed-frequency photon from a laser. The two-photon absorption process is modeled via a combination of rovibrational and electronic single-photon transitions, using a wave-function formalism. A two-photon absorption cross section as a function of the entanglement delay time between the two photons is computed, then subjected to a fast Fourier transform to produce an energy spectrum. The program then detects peaks in the Fourier spectrum and displays the energy levels of very short-lived intermediate quantum states (or virtual states) of the molecule. Such virtual states were only previously accessible using ultra-fast (femtosecond) laser systems. However, with the use of a single-frequency continuous wave laser to produce SPDC photons, and QEMASS program, these short-lived molecular states can now be studied using much simpler laser systems. QE-MASS can also show the dependence of the Fourier spectrum on the tuning range of the entanglement time of any externally introduced optical-path delay time. QE-MASS can be extended to any molecule for which an appropriate spectroscopic database is available. It is a means of performing an a priori parametric analysis of entangled photon spectroscopy for development and implementation of emerging quantum-spectroscopic sensing techniques. QE-MASS is currently implemented using the Mathcad software package.

  19. Practical electronics handbook

    CERN Document Server

    Sinclair, Ian R

    2013-01-01

    Practical Electronics Handbook, Third Edition provides the frequently used and highly applicable principles of electronics and electronic circuits.The book contains relevant information in electronics. The topics discussed in the text include passive and active discrete components; linear and digital I.C.s; microprocessors and microprocessor systems; digital-analogue conversions; computer aids in electronics design; and electronic hardware components.Electronic circuit constructors, service engineers, electronic design engineers, and anyone with an interest in electronics will find the book ve

  20. On the rich eight branch spectrum of the oblique propagating longitudinal waves in partially spin polarized electron-positron-ion plasmas

    CERN Document Server

    Andreev, Pavel A

    2016-01-01

    We consider the separate spin evolution of electrons and positrons in electron-positron and electron-positron-ion plasmas. We consider oblique propagating longitudinal waves in this systems. We report presence of the spin-electron acoustic waves and their dispersion dependencies. In electron-positron plasmas, similarly to the electron-ion plasmas, we find one spin-electron acoustic wave (SEAW) at propagation parallel or perpendicular to the external field and two spin-electron acoustic waves at the oblique propagation. At the parallel or perpendicular propagation of the longitudinal waves in electron-positron-ion plasmas we find four branches: the Langmuir wave, the positron-acoustic wave and pair of waves having spin nature, they are the SEAW and, as we called it, spin-electron-positron acoustic wave (SEPAW). At the oblique propagation we find eight longitudinal waves: the Langmuir wave, Trivelpiece-Gould wave, pair of positron-acoustic waves, pair of SEAWs, and pair of SEPAWs. Thus, for the first time, we r...

  1. The electronic spectrum of graphene nanoribbons with zigzag edges based on the SSH model%基于 SSH 模型的锯齿型边石墨烯纳米带电子能谱研究磁

    Institute of Scientific and Technical Information of China (English)

    陈琼; 童国平; 李盛

    2014-01-01

    利用SSH( Su-Schrieffer-Heeger)模型研究了2条聚乙炔链键与键平行和非平行结构耦合的电子能谱。两者的电子能谱与耦合强度之间有类似关系,但平行结构受耦合强度的影响更大些。在此基础上,将耦合链模型应用于锯齿型石墨烯纳米带的电子能谱计算,并给出了解析色散关系。同时,还研究了电子能谱与其耦合强度的关系,耦合越强,能带越宽。%The electronic spectrum of two coupled polyacetylene chains with bond-bond parallel and non-paral-lel was studied by using the SSH ( Su-Schrieffer-Heeger) model.Both the spectra were related to the coupling intensity, but the effect of the bond-bond parallel structure on the spectrum was obvious compared to the non-parallel .Based on this model, the electronic spectrum of graphene nanoribbons with zigzag edges was calculat-ed and the energy dispersion relation was derived.The relationship between the spectrum and the coupling in-tensity was also discussed, which showed that the stronger the coupling was the wider the energy band ap-peared.

  2. Microbial Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, Merry [American Society for Microbiology (ASM), Washington, DC (United States); Wall, Judy D. [Univ. of Missouri, Columbia, MO (United States)

    2006-10-01

    natural gas from the subsurface. The participants discussed--key microbial conversion paths; overarching research issues; current funding models and microbial energy research; education, training, interdisciplinary cooperation and communication. Their recommendations are--Cellulose and lignocellulose are the preferred substrates for producing liquid transportation fuels, of which ethanol is the most commonly considered example. Generating fuels from these materials is still difficult and costly. A number of challenges need to be met in order to make the conversion of cellulose and lignocellulose to transportation fuels more cost-competitive. The design of hydrogen-producing bioreactors must be improved in order to more effectively manage hydrogen removal, oxygen exclusion, and, in the case of photobioreactors, to capture light energy more efficiently. Methane production may be optimized by fine-tuning methanogenic microbial communities. The ability to transfer electrons to an anode in a microbial fuel cell is probably very broadly distributed in the bacterial world. The scientific community needs a larger inventory of cultivated microorganisms from which to draw for energy conversion development. New and unusual organisms for manufacturing fuels and for use in fuel cells can be discovered using bioprospecting techniques. Particular emphasis should be placed on finding microbes, microbial communities, and enzymes that can enhance the conversion of lignocellulosic biomass to usable sugars. Many of the microbial processes critical to energy conversion are carried out by complex communities of organisms, and there is a need to better understand the community interactions that make these transformations possible. Better understanding of microbial community structure, robustness, networks, homeostasis, and cell-to-cell signaling is also needed. A better understanding of the basic enzymology of microorganisms is needed in order to move forward more quickly with microbial energy

  3. A computational investigation of the photochemical oxaziridine and amide conversion process of open-chain conjugated nitrone with electron-withdrawing trifluoromethyl group on nitrogen

    Indian Academy of Sciences (India)

    Praveen Saini; Anjan Chattopadhyay

    2015-10-01

    This computational study investigates the photo-excitation process and subsequent photoproduct formation steps through non-radiative deactivation channels in open-chain conjugated N-substituted nitrone systems (model compounds of corresponding retinylnitrones) having electron-withdrawing groups on nitrogen. Calculations mostly based on CASSCF/6-31G* and CASMP2/6-31G* level of theories on a representative system with N-trifluoromethyl substituent have predicted initial photo-excitation to a planar singlet state. This photochemical path is subsequently followed by a barrierless non-radiative channel towards the lowest-energy conical intersection (CI) geometry having a terminal CNO kink, and situated at 30 kcal/mol below the planar excited state. Following the direction of its gradient difference (GD) vectors, an oxaziridine-type species (RC−O = 1.38 Å, RN−O = 1.53 Å, < CNO= 55.8°) appears at 3–6 kcal mol−1 below the ground state nitrone system through a transition state (along its reverse direction of minimum-energy path), situated on the reaction pathway. This species with an elongated N-O bond seems to be heading towards an amide geometry. On the other hand, in the opposite GD vector direction a proper oxaziridine geometry has been obtained with a much shorter N-O bond distance (RN−O = 1.42 Å).

  4. Cooperative internal conversion process by proton exchange

    CERN Document Server

    Kálmán, Péter

    2016-01-01

    A generalization of the recently discovered cooperative internal conversion process is investigated theoretically. In the cooperative internal conversion process by proton exchange investigated the coupling of bound-free electron and proton transitions due to the dipole term of their Coulomb interaction permits cooperation of two nuclei leading to proton exchange and an electron emission. General expression of the cross section of the process obtained in the one particle spherical nuclear shell model is presented. As a numerical example the cooperative internal conversion process by proton exchange in $Al$ is dealt with. As a further generalization, cooperative internal conversion process by heavy charged particle exchange and as an example of it the cooperative internal conversion process by triton exchange is discussed. The process is also connected to the field of nuclear waste disposal.

  5. Suprathermal electron energy spectrum and nonlocally affected plasma-wall interaction in helium/air micro-plasma at atmospheric pressure

    Science.gov (United States)

    Demidov, V. I.; Adams, S. F.; Miles, J. A.; Koepke, M. E.; Kurlyandskaya, I. P.

    2016-10-01

    Details of ground-state and excited-state neutral atoms and molecules in an atmospheric-pressure micro-discharge plasma may be obtained by plasma electron spectroscopy (PLES), based on a wall probe. The presence and transport of energetic (suprathermal) electrons, having a nonlocal origin, are responsible for electrostatic charging of the plasma boundary surfaces to potentials many times that associated with the ambient electron kinetic energy. The energy-flux distribution function is shown to be controllable for applications involving analysis of composition and processes taking place in a multiphase (plasma-gas-solid), chemically reactive, interaction region.

  6. Zellweger Spectrum

    Science.gov (United States)

    ... severe defect, resulting in essentially nonfunctional peroxisomes. This phenomenon produces the range of severity of the disorders. How is the Zellweger Spectrum Diagnosed? The distinctive shape of the head and face of a child born with one of the diseases of the ...

  7. Sensitivity analysis of the influence of the medium energy and initial fluence FWHM of electron determining a Bremsstrahlung photon spectrum of a linear accelerator; Analisis de sensibilidad de la influencia de la energia media FWHM de la influencia inicial de electrones en la determinacion de un espectro de fotones Bremsstrahlung de un acelerador lineal

    Energy Technology Data Exchange (ETDEWEB)

    Juste, B.; Miro, R.; Verdu, G.; Diez, S.; Campayo, J. M.

    2012-11-01

    A correct dose calculation in patient under radiotherapy treatments requires and accurate description of the radiation source. The main goal of the present work is to study the effects of initial electron beam characteristics on Monte Carlo calculated absorbed dose distribution for a 6 MeV linac photon beam. To that, we propose a methodology to determine the initial electron fluence before hitting the accelerator target for an Elektra Precis a medical linear accelerator. The method used for the electron radiation source description is based on a Software for Uncertainty and Sensitivity Analysis (SUSA) and Monte Carlo simulations using the MCNP5 transport code. This electron spectrum has been validated by means of comparison of its resulting depth dose curve in a water cube with experimental data being the mean difference below the 1%. (Author)

  8. Investigation of Carboxylic Acid-Neodymium Conversion Films on Magnesium Alloy

    Science.gov (United States)

    Cui, Xiufang; Liu, Zhe; Lin, Lili; Jin, Guo; Wang, Haidou; Xu, Binshi

    2015-01-01

    The new carboxylic acid-neodymium anhydrous conversion films were successfully prepared and applied on the AZ91D magnesium alloy surface by taking absolute ethyl alcohol as solvent and four kinds of soluble carboxylic acid as activators. The corrosion resistance of the coating was measured by potentiodynamic polarization test in 3.5 wt.% NaCl solution in pH 7.0. The morphology, structure, and constituents of the coating were observed by scanning electron microscope, energy dispersivespectrum, x-ray photoelectron spectrum, and Fourier infrared spectrometer. Results show that corrosion resistance properties of samples coated with four different anhydrous conversion films were improved obviously. The corrosion potential increased, corrosion current density decreased, and polarization resistance increased. Among these four kinds of conversion films the one added with phytic exhibits the best corrosion resistant property. The mechanism of anhydrous-neodymium conversion film formation is also analyzed in this paper. It reveals that the gadolinium conversion coating is mainly composed of stable Nd2O3, MgO, Mg(OH)2, and carboxylate of Nd. And that the sample surface is rich in organic functional groups.

  9. An Application of the Direct Coulomb Electron Pair Production Process to the Energy Measurement of the "VH-Group" in the "Knee" Region of the "All-Particle" Energy Spectrum

    Science.gov (United States)

    Derrickson, J. H.; Wu, J.; Christl, M. J.; Fountain, W. F.; Parnell, T. A.

    1999-01-01

    The "all-particle" cosmic ray energy spectrum appears to be exhibiting a significant change in the spectral index just above approximately 3000 TeV. This could indicate (1) a change in the propagation of the cosmic rays in the galactic medium, and/or (2) the upper limit of the supernova shock wave acceleration mechanism, and/or (3) a new source of high-energy cosmic rays. Air shower and JACEE data indicate the spectral change is associated with a composition change to a heavier element mixture whereas DICE does not indicate this. A detector concept will be presented that utilizes the energy dependence of the production of direct Coulomb electron-positron pairs by energetic heavy ions. Monte Carlo simulations of a direct electron pair detector consisting of Pb target foils interleaved with planes of 1-mm square scintillating optical fibers will be discussed. The goal is to design a large area, non-saturating instrument to measure the energy spectrum of the individual cosmic ray elements in the "VH-group" for energies greater than 10 TeV/nucleon.

  10. Electromagnetic wave energy conversion research

    Science.gov (United States)

    Bailey, R. L.; Callahan, P. S.

    1975-01-01

    Known electromagnetic wave absorbing structures found in nature were first studied for clues of how one might later design large area man-made radiant-electric converters. This led to the study of the electro-optics of insect dielectric antennae. Insights were achieved into how these antennae probably operate in the infrared 7-14um range. EWEC theoretical models and relevant cases were concisely formulated and justified for metal and dielectric absorber materials. Finding the electromagnetic field solutions to these models is a problem not yet solved. A rough estimate of losses in metal, solid dielectric, and hollow dielectric waveguides indicates future radiant-electric EWEC research should aim toward dielectric materials for maximum conversion efficiency. It was also found that the absorber bandwidth is a theoretical limitation on radiant-electric conversion efficiency. Ideally, the absorbers' wavelength would be centered on the irradiating spectrum and have the same bandwith as the irradiating wave. The EWEC concept appears to have a valid scientific basis, but considerable more research is needed before it is thoroughly understood, especially for the complex randomly polarized, wide band, phase incoherent spectrum of the sun. Specific recommended research areas are identified.

  11. Special issue: Plasma Conversion

    NARCIS (Netherlands)

    Nozaki, T.; Bogaerts, A.; Tu, X.; van de Sanden, M. C. M.

    2017-01-01

    With growing concern of energy and environmental issues, the combination of plasma and heterogeneous catalysts receives special attention in greenhouse gas conversion, nitrogen fixation and hydrocarbon chemistry. Plasma gas conversion driven by renewable electricity is particularly important for the

  12. [Difference in the Mössbauer spectrum parameters and electron structure of active sites of non-equivalent subunits of tetrameric deoxyhemoglobin and deoxymyoglobin].

    Science.gov (United States)

    Burykin, B N; Khleskov, V I; Oshtrakh, M I; Semenkin, V A

    1987-01-01

    The calculations of the electronic structure of fifth-coordinated ferroporphyrin-imidazole complexes modeling alpha- and beta-subunits in desoxyhemoglobin and desoxymyoglobin are made using the interative extended Hückel method. The features of the electronic structure of the model complexes resulting from the stereochemical differences of the active site are studied and compared. Theoretical calculations of the Mössbauer parameters of model complexes are made and compared with experimental data. The results show that basic features of the Mössbauer parameters are qualitatively confirmed by the theoretical analysis. The necessity of the accounting of the stereochemical and electronic structure nonequivalence of nonidentical subunits in tetrameric desoxyhemoglobins during the Mössbauer spectra approximation is also confirmed.

  13. LDRD final report : energy conversion using chromophore-functionalized carbon nanotubes.

    Energy Technology Data Exchange (ETDEWEB)

    Vance, Andrew L.; Zifer, Thomas; Zhou, Xinjian; Leonard, Francois Leonard; Wong, Bryan Matthew; Kane, Alexander; Katzenmeyer, Aaron Michael; Krafcik, Karen Lee

    2010-09-01

    With the goal of studying the conversion of optical energy to electrical energy at the nanoscale, we developed and tested devices based on single-walled carbon nanotubes functionalized with azobenzene chromophores, where the chromophores serve as photoabsorbers and the nanotube as the electronic read-out. By synthesizing chromophores with specific absorption windows in the visible spectrum and anchoring them to the nanotube surface, we demonstrated the controlled detection of visible light of low intensity in narrow ranges of wavelengths. Our measurements suggested that upon photoabsorption, the chromophores isomerize to give a large change in dipole moment, changing the electrostatic environment of the nanotube. All-electron ab initio calculations were used to study the chromophore-nanotube hybrids, and show that the chromophores bind strongly to the nanotubes without disturbing the electronic structure of either species. Calculated values of the dipole moments supported the notion of dipole changes as the optical detection mechanism.

  14. KSTAR装置逃逸电子同步辐射功率谱的研究%A Study on Spectrum of Synchrotron Radiation of the Runaway Electrons in KSTAR Tokamak

    Institute of Scientific and Technical Information of China (English)

    段卓琦; 朱俊; 陈忠勇

    2012-01-01

    电子逃逸是托卡马克等离子体中一种普遍的现象.对逃逸电子的监测是保护装置第一壁材料的基础.托卡马克上等离子体芯部逃逸电子发射的同步辐射是利用红外相机测量,但是红外相机的光路成本高,相机本身也比较昂贵.通过分析KSTAR装置逃逸电子的同步辐射功率谱,研究了逃逸电子同步辐射波长与能量的关系,拟发展新型的逃逸电子诊断系统.%In tokamak plasmas, the escape of the electrons is a common phenomenon. It is important to detect the runaway elec- trons in order to protect first wall components of the device. The synchrotron radiation emitted by the runaway electrons in the core of tokamak plasmas can be measured with an infrared camera. But the infrared camera system is expensive. In this paper, the spectrum of synchrotron radiation of the runaway electrons in KSTAR is analyzed. The relationship between the wavelength of syn- chrotron radiation of the runaway electrons and the energy of the runaway electrons is studied. It is found that the visible camera can be used to measure runaway electrons in KSATR.

  15. Ab initio calculation of the electronic spectrum of azobenzene dyes and its impact on the design of optical data storage materials

    DEFF Research Database (Denmark)

    Åstrand, Per-Olof; Ramanujam, P.S.; Hvilsted, Søren

    2000-01-01

    Electronic excitation energies of 16 azobenzene dyes have been calculated by ab initio methods within the second-order polarization propagator approximation (SOPPA). Good agreement with expriment is found for the lowest singlet and triplet states for both the trans- and cis-azobenzene molecules......, the experimental singlet π → π* transitions are reproduced for a set of azobenzene dyes with different electron donor and acceptor groups and the correct shifts in excitation energy are obtained for the different substituents. It has also been demonstrated that ab initio methods can be used to determine suitable...... candidates for azo components used in materials for data storage....

  16. The Influence of Ultrasound on the Energy Spectrum of Electron and Holein InAs/GaAs Heterosystem with InAs Quantum Dots

    Directory of Open Access Journals (Sweden)

    R.M. Peleshchak

    2016-12-01

    Full Text Available On the basis of the method of electron-deformation relation and perturbation theory the model of heterostructure with spherical quantum dots which is exposed to ultrasound is developed. Within this model it is investigated the influence of the acoustic wave on the ground state energy of electron and hole, the band gap energy and energy of recombination radiation of InAs/GaAs heterostructure with InAs spherical quantum dots. The offered model considers the distortion of the form of quantum dot and its volume change under the influence of the acoustic wave.

  17. Integration of Semiconducting Sulfides for Full-Spectrum Solar Energy Absorption and Efficient Charge Separation.

    Science.gov (United States)

    Zhuang, Tao-Tao; Liu, Yan; Li, Yi; Zhao, Yuan; Wu, Liang; Jiang, Jun; Yu, Shu-Hong

    2016-05-23

    The full harvest of solar energy by semiconductors requires a material that simultaneously absorbs across the whole solar spectrum and collects photogenerated electrons and holes separately. The stepwise integration of three semiconducting sulfides, namely ZnS, CdS, and Cu2-x S, into a single nanocrystal, led to a unique ternary multi-node sheath ZnS-CdS-Cu2-x S heteronanorod for full-spectrum solar energy absorption. Localized surface plasmon resonance (LSPR) in the nonstoichiometric copper sulfide nanostructures enables effective NIR absorption. More significantly, the construction of pn heterojunctions between Cu2-x S and CdS leads to staggered gaps, as confirmed by first-principles simulations. This band alignment causes effective electron-hole separation in the ternary system and hence enables efficient solar energy conversion.

  18. Chinese Conversation Structure

    Institute of Scientific and Technical Information of China (English)

    LIU Yan

    2016-01-01

    This paper aims to describe the features of Chinese conversation structure. Specifically speaking, the structure will be analyzed from the following four aspects:openings and pre-sequence, adjacency pairs, pre-closing and closing. Generally speak-ing, Chinese conversation structure is similar to English conversation structure. But still a lot of differences are found due to cul-tural factors.

  19. Solution-processed organic tandem solar cells with power conversion efficiencies >12%

    Science.gov (United States)

    Li, Miaomiao; Gao, Ke; Wan, Xiangjian; Zhang, Qian; Kan, Bin; Xia, Ruoxi; Liu, Feng; Yang, Xuan; Feng, Huanran; Ni, Wang; Wang, Yunchuang; Peng, Jiajun; Zhang, Hongtao; Liang, Ziqi; Yip, Hin-Lap; Peng, Xiaobin; Cao, Yong; Chen, Yongsheng

    2016-12-01

    An effective way to improve the power conversion efficiency of organic solar cells is to use a tandem architecture consisting of two subcells, so that a broader part of the solar spectrum can be used and the thermalization loss of photon energy can be minimized. For a tandem cell to work well, it is important for the subcells to have complementary absorption characteristics and generate high and balanced (matched) currents. This requires a rather challenging effort to design and select suitable active materials for use in the subcells. Here, we report a high-performance solution-processed, tandem solar cell based on the small molecules DR3TSBDT and DPPEZnP-TBO, which offer efficient, complementary absorption when used as electron donor materials in the front and rear subcells, respectively. Optimized devices achieve a power conversion efficiency of 12.50% (verified 12.70%), which represents a new level of capability for solution-processed, organic solar cells.

  20. Ab initio calculation of the electronic spectrum of azobenzene dyes and its impact on the design of optical data storage materials

    DEFF Research Database (Denmark)

    Åstrand, Per-Olof; Ramanujam, P.S.; Hvilsted, Søren

    2000-01-01

    Electronic excitation energies of 16 azobenzene dyes have been calculated by ab initio methods within the second-order polarization propagator approximation (SOPPA). Good agreement with expriment is found for the lowest singlet and triplet states for both the trans- and cis-azobenzene molecules. ...

  1. Elements of energy conversion

    CERN Document Server

    Russell, Charles R

    2013-01-01

    Elements of Energy Conversion brings together scattered information on the subject of energy conversion and presents it in terms of the fundamental thermodynamics that apply to energy conversion by any process. Emphasis is given to the development of the theory of heat engines because these are and will remain most important power sources. Descriptive material is then presented to provide elementary information on all important energy conversion devices. The book contains 10 chapters and opens with a discussion of forms of energy, energy sources and storage, and energy conversion. This is foll

  2. NGL data conversion system

    Science.gov (United States)

    Shoji, Masahiro; Horiuchi, Nobuyasu

    2005-06-01

    We are developing a NGL data conversion system for EPL, for LEEPL, and for EBDW, which is based on our established photomask data conversion system, PATACON PC-cluster. For EPL data conversion, it has SF division, Complementary division, Stitching, Proximity effect correction, Alignment mark insertion, EB stepper control data creation, and Mask inspection data creation. For LEEPL data conversion, it has Pattern checking, Complementary division, Stitching, Stress distortion correction, Alignment mark insertion, and Mask inspection data creation. For EB direct-writing data conversion, it has Proximity effect correction and Extraction of aperture pattern for cell projection exposure.

  3. Hydrogen Spectrum

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    The series of absorption or emission lines that are characteristic of the hydrogen atom. According to the Bohr theory of the hydrogen atom, devised by Danish physicist Neils Bohr (1885-1962) in 1913, the hydrogen atom can be envisaged as consisting of a central nucleus (a proton) around which a single electron revolves. The electron is located in one of a number of possible permitted orbits, each...

  4. Beyond the Spectrum: Rethinking Autism

    Directory of Open Access Journals (Sweden)

    Heather Thomas

    2017-03-01

    Full Text Available The "spectrum" has become the dominant metaphor for conceptualizing autism, with fundamental consequences for notions of disability, diversity, and normality. In this article, we draw on ethnographic research with autistic communities to explore how the notion of the autism spectrum has become a focus of explicit identification, reflection, and contestation. To further this inquiry, we place these debates into conversation with earlier debates regarding another spectrum—the Kinsey Scale, a "spectrum" for conceptualizing sexual orientation that first appeared in 1948 but has been critiqued since the 1970s. How might responses to the Kinsey Scale (like the Klein Grid contribute to rethinking the autism spectrum? This is a question about the cultural and political implications of metaphors and conceptual models. It is of broad importance because the spectrum metaphor is being extended to a range of conditions beyond autism itself. Our goal is thus to build on insights from sexuality studies as well as the insights of autistic persons, advocates, and researchers who wish to forestall the naturalization of "the spectrum." In doing so, we seek to contribute to a discussion of what alternative frameworks might bring to questions of social justice, ability, and human flourishing.

  5. The e− Spectrum and e+ Spectrum from AMS

    CERN Document Server

    CERN. Geneva

    2015-01-01

    Precision measurements by AMS on the ISS of the primary cosmic-ray electron flux in the range 0.5 to 700 GeV and the positron flux in the range 0.5 to 500 GeV are presented. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron flux and the positron flux change their behavior at ∼30 GeV but the fluxes are significantly different in their magnitude and energy dependence. Between 20 and 200 GeV the positron spectral index is significantly harder than the electron spectral index.

  6. Hard electronics; Hard electronics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    In the fields of power conversion devices and broadcasting/communication amplifiers, high power, high frequency and low losses are desirable. Further, for electronic elements in aerospace/aeronautical/geothermal surveys, etc., heat resistance to 500degC is required. Devices which respond to such hard specifications are called hard electronic devices. However, with Si which is at the core of the present electronics, the specifications cannot fully be fulfilled because of the restrictions arising from physical values. Accordingly, taking up new device materials/structures necessary to construct hard electronics, technologies to develop these to a level of IC were examined and studied. They are a technology to make devices/IC of new semiconductors such as SiC, diamond, etc. which can handle higher temperature, higher power and higher frequency than Si and also is possible of reducing losses, a technology to make devices of hard semiconducter materials such as a vacuum microelectronics technology using ultra-micro/high-luminance electronic emitter using negative electron affinity which diamond, etc. have, a technology to make devices of oxides which have various electric properties, etc. 321 refs., 194 figs., 8 tabs.

  7. Polarization of electron cyclotron emission spectra in LHD

    Energy Technology Data Exchange (ETDEWEB)

    Vries, P.C. de; Nagayama, Y.; Kawahata, K.; Inagaki, S.; Sasao, H. [National Inst. for Fusion Science, Toki, Gifu (Japan); Nagasaki, K.

    1999-07-01

    Electron cyclotron emission (ECE) can be used to determine the electron temperature profile in magnetized plasmas. The complex structure of the magnetic field configuration in the Large Helical Device (LHD), which has a large shear, complicates the analysis of the ECE spectrum. In a sheared magnetic field the propagation of X and O-mode polarization through the plasma are coupled, causing mode conversion and polarization rotation. Mode scrambling is also caused by wall reflections. In this report, this mode conversion in LHD is numerically analyzed. It was found that at low density mode conversion scrambles the ECE spectra. However, at higher density (n{sub eo} > 1.0{center_dot}10{sup 19} m{sup -3}) the polarization mode is found to rotate with the sheared magnetic field, yielding only a negligible mode conversion. Wall reflections are found to depolarize the ECE spectrum. Notwithstanding the LHD magnetic configuration, it is shown that temperature profiles could be revealed from the ECE spectra. (author)

  8. Materials in energy conversion, harvesting, and storage

    CERN Document Server

    Lu, Kathy

    2014-01-01

    First authored book to address materials' role in the quest for the next generation of energy materials Energy balance, efficiency, sustainability, and so on, are some of many facets of energy challenges covered in current research. However, there has not been a monograph that directly covers a spectrum of materials issues in the context of energy conversion, harvesting and storage. Addressing one of the most pressing problems of our time, Materials in Energy Conversion, Harvesting, and Storage illuminates the roles and performance requirements of materials in energy an

  9. Approaches for biological and biomimetic energy conversion

    OpenAIRE

    LaVan, David A.; Cha, Jennifer N.

    2006-01-01

    This article highlights areas of research at the interface of nanotechnology, the physical sciences, and biology that are related to energy conversion: specifically, those related to photovoltaic applications. Although much ongoing work is seeking to understand basic processes of photosynthesis and chemical conversion, such as light harvesting, electron transfer, and ion transport, application of this knowledge to the development of fully synthetic and/or hybrid devices is still in its infanc...

  10. Fission Spectrum

    Science.gov (United States)

    Bloch, F.; Staub, H.

    1943-08-18

    Measurements of the spectrum of the fission neutrons of 25 are described, in which the energy of the neutrons is determined from the ionization produced by individual hydrogen recoils. The slow neutrons producing fission are obtained by slowing down the fast neutrons from the Be-D reaction of the Stanford cyclotron. In order to distinguish between fission neutrons and the remaining fast cyclotron neutrons both the cyclotron current and the pusle amplifier are modulated. A hollow neutron container, in which slow neutrons have a lifetime of about 2 milliseconds, avoids the use of large distances. This method results in much higher intensities than the usual modulation arrangement. The results show a continuous distribution of neutrons with a rather wide maximum at about 0.8 MV falling off to half of its maximum value at 2.0 MV. The total number of netrons is determined by comparison with the number of fission fragments. The result seems to indicate that only about 30% of the neutrons have energies below .8 MV. Various tests are described which were performed in order to rule out modification of the spectrum by inelastic scattering. Decl. May 4, 1951

  11. Jet-cooled fluorescence excitation spectrum, carbonyl wagging, and ring-puckering potential energy functions of 3-cyclopenten-1-one in its S1(n,π*) electronic excited state

    Science.gov (United States)

    Sagear, Paul; Laane, Jaan

    1995-05-01

    The jet-cooled fluorescence excitation spectrum of 3-cyclopenten-1-one has been recorded in the 308-330 nm region, and the electronic origin for the S1(n,π*) state of A2 symmetry was observed at 30 229 cm-1. The observed spectrum consists of more than 80 bands involving primarily ν3 (carbonyl stretch), ν29 (carbonyl out-of-plane wagging), and ν30 (ring puckering). Bands were also assigned to combinations with seven other vibrational modes. The energies for the v=0 to 11 quantum states of ν29 were measured and used to determine a one-dimensional potential energy function. This function has energy minima at wagging angles of ±24° and a barrier to inversion of 939 cm-1. Four bands associated with ν30 were observed and were used to determine an asymmetric single-minimum one-dimensional ring-puckering potential energy function for the S1(n,π*) state. The ring-puckering energy levels in the ν29 vibrational excited states are little changed from the v=0 state indicating that there is little interaction between the carbonyl wagging and the ring-puckering motions.

  12. Assessment of electron-vibrational interaction (EVI) parameters of YAG:Ce3 +, TAG:Ce3 + and LuAG:Ce3 + garnet phosphors by spectrum fitting method

    Science.gov (United States)

    Nair, Govind B.; Dhoble, S. J.

    2017-02-01

    The electron-vibrational interaction (EVI) in 4f ↔ 5d optical transitions of Ce3 + ions in YAG, TAG and LuAG garnet phosphors have been analysed in this work. The main EVI parameters that have been estimated and reported here are Huang-Rhys factor, effective phonon energy, Stokes shift, red shift and Zero-phonon line position. The EVI parameters were estimated from the room temperature photoluminescence results that were recently reported. The spectrum fitting method was employed to determine the EVI parameters. An emission band was modelled with the aid of the calculated EVI parameters. The agreement between the modelled emission bands with the experimentally obtained ones validated the estimated values of EVI parameters.

  13. A simple protocol for the michael addition of indoles with electron deficient olefins catalysed by TBAHS in aqueous media and their broad spectrum antibacterial activity

    Indian Academy of Sciences (India)

    M Damodiran; R Senthil Kumar; P M Sivakumar; Mukesh Doble; Paramasivan T Perumal

    2009-01-01

    Tetrabutylammonium hydrogen sulfate catalysed addition of indoles to electron deficient olefins in water generated the corresponding Michael adducts in good to excellent yield. The Michael addition of indole occurred regioselectively at position 3 and the -alkylated products have not been observed. The synthesized compounds were tested for their antibacterial activity against four microorganisms namely, E. coli NCIM 2931, S. aureus NCIM 5021, P. vulgaris NCIM 2813, P. aeruginosa NCIM 5029 by micro dilution method. These compounds showed MIC (Minimum Inhibitory Concentration) values in the range of 0.16-2.67 M.

  14. Local study of the energy spectrum of electrons in CdSe/ZnSe QD structure by current DLTS cooperated with AFM

    Energy Technology Data Exchange (ETDEWEB)

    Litvinov, Vladimir; Sadofyev, Yuri; Rybin, Nikolay [Ryazan State Radioengineering University, Gagarin str. 59/1, 390005 Ryazan (Russian Federation); Kozlovsky, Vladimir [P. N. Lebedev Physical Institute RAS, Leninsky pr. 53, 119991 Moscow (Russian Federation)

    2012-08-15

    CdSe/ZnSe QD structure was investigated by current deep level transient spectroscopy (DLTS) with Laplace transform cooperated with atomic force microscopy (AFM). Cathodoluminescence (CL) measurements were carried out too. Basing on Laplace current DLTS with AFM and CL data an activation energy of electron emission from the quantized levels in a small group of CdSe QDs was measured. We have demonstrated the advanced capabilities of the new method of studying the electrical properties of nano-objects. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Uranium conversion; Conversion de l`uranium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    This booklet is a presentation of the activities of the Comurhex company, created in 1971 and which became a 100% Cogema`s daughter company in 1992. The Comurhex company is in charge of the conversion of natural uranium into gaseous uranium hexafluoride (UF{sub 6}). The two steps of the conversion operation are performed in the Malvesi and Pierrelatte (France) industrial sites and represent 31% (14000 t/year) of the uranium conversion capacity of western countries. The refining and UF{sub 4} production (Malvesi) and the UF{sub 6} fabrication (Pierrelatte) processes are described. Comurhex is also one of the few companies in the world which produces UF{sub 6} from the uranium of spent fuels. (J.S.)

  16. Rigorous quantitative elemental microanalysis by scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDS) with spectrum processing by NIST DTSA-II

    Science.gov (United States)

    Newbury, Dale E.; Ritchie, Nicholas W. M.

    2014-09-01

    Quantitative electron-excited x-ray microanalysis by scanning electron microscopy/silicon drift detector energy dispersive x-ray spectrometry (SEM/SDD-EDS) is capable of achieving high accuracy and high precision equivalent to that of the high spectral resolution wavelength dispersive x-ray spectrometer even when severe peak interference occurs. The throughput of the SDD-EDS enables high count spectra to be measured that are stable in calibration and resolution (peak shape) across the full deadtime range. With this high spectral stability, multiple linear least squares peak fitting is successful for separating overlapping peaks and spectral background. Careful specimen preparation is necessary to remove topography on unknowns and standards. The standards-based matrix correction procedure embedded in the NIST DTSA-II software engine returns quantitative results supported by a complete error budget, including estimates of the uncertainties from measurement statistics and from the physical basis of the matrix corrections. NIST DTSA-II is available free for Java-platforms at: http://www.cstl.nist.gov/div837/837.02/epq/dtsa2/index.html).

  17. X-ray photoelectron spectrum and electronic properties of a noncentrosymmetric chalcopyrite compound HgGa(2)S(4): LDA, GGA, and EV-GGA.

    Science.gov (United States)

    Reshak, Ali Hussain; Khenata, R; Kityk, I V; Plucinski, K J; Auluck, S

    2009-04-30

    An all electron full potential linearized augmented plane wave method has been applied for a theoretical study of the band structure, density of states, and electron charge density of a noncentrosymmetric chalcopyrite compound HgGa(2)S(4) using three different approximations for the exchange correlation potential. Our calculations show that the valence band maximum (VBM) and conduction band minimum (CBM) are located at Gamma resulting in a direct energy gap of about 2.0, 2.2, and 2.8 eV for local density approximation (LDA), generalized gradient approximation (GGA), and Engel-Vosko (EVGGA) compared to the experimental value of 2.84 eV. We notice that EVGGA shows excellent agreement with the experimental data. This agreement is attributed to the fact that the Engel-Vosko GGA formalism optimizes the corresponding potential for band structure calculations. We make a detailed comparison of the density of states deduced from the X-ray photoelectron spectra with our calculations. We find that there is a strong covalent bond between the Hg and S atoms and Ga and S atoms. The Hg-Hg, Ga-Ga, and S-S bonds are found to be weaker than the Hg-S and Ga-S bonds showing that a covalent bond exists between Hg and S atoms and Ga and S atoms.

  18. Computers and conversation

    CERN Document Server

    Luff, Paul; Gilbert, Nigel G

    1986-01-01

    In the past few years a branch of sociology, conversation analysis, has begun to have a significant impact on the design of human*b1computer interaction (HCI). The investigation of human*b1human dialogue has emerged as a fruitful foundation for interactive system design.****This book includes eleven original chapters by leading researchers who are applying conversation analysis to HCI. The fundamentals of conversation analysis are outlined, a number of systems are described, and a critical view of their value for HCI is offered.****Computers and Conversation will be of interest to all concerne

  19. An ENDOR spectrum of H atoms in solid H{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Kumada, Takayuki; Kumagai, J.; Aratono, Yasuyuki; Miyazaki, T. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kitagawa, N.; Noda, T.

    1998-10-01

    An ENDOR spectrum of H atoms produced in the {gamma}-rays irradiated solid H{sub 2} was measured at 4.2 K in order to elucidate the structures of the local environment of the H atoms in solid H{sub 2}. We found that the H atoms were not trapped in interstitial sites but in substitutional sites of the solid, and almost all ortho-H{sub 2} molecules at the first nearest sites from the H atoms converted into para-H{sub 2} molecules. This result shows that the ortho-para conversion is induced by electron spins of the H atoms. (author)

  20. Coherent quantum control of internal conversion: {S}_{2}\\;\\leftrightarrow \\;{S}_{1} in pyrazine via {S}_{0}\\;\\to \\;{S}_{2}/{S}_{1} weak field excitation

    Science.gov (United States)

    Grinev, Timur; Shapiro, Moshe; Brumer, Paul

    2015-09-01

    Coherent control of internal conversion (IC) between the first (S1) and second (S2) singlet excited electronic states in pyrazine, where the S2 state is populated from the ground singlet electronic state S0 by weak field excitation, is examined. Control is implemented by shaping the laser which excites S2. Excitation and IC are considered simultaneously, using the recently introduced resonance-based control approach. Highly successful control is achieved by optimizing both the amplitude and phase profiles of the laser spectrum. The dependence of control on the properties of resonances in S2 is demonstrated.

  1. Therapeutic electrons bunch energy spectrums: correlation among physical parameters and quality; Espectros de energia de feixe de eletrons terapeuticos: correlacao entre parametros fisicos e qualidade

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Rolando Fonseca

    1993-07-01

    A new approach was described for clinical and physical parameters used in radiotherapy planning and dosimetry, studying their dependencies on spectral widths. Two different models of clinical linear accelerators were used-Mevatron 74 (UNICAMP) and Mevatron 12 (HC/FMRP/Ribeirao Preto). Mevatron 74 produces beams with nominal energies from 5 up to 12 MeV and Mevatron 12 from 3 up to 11 MeV. It was verified that the values of clinical parameters expected from a semi-empirical theory differ from that obtained experimentally. Such differences are relevant from the point of view of the design of electron accelerators, as well as, of the target clinical results. (author)

  2. TD-DFT Study on the Electronic Spectrum Properties of 2,7'-(Ethylene)-bis-8-hydroxyquinoline and Its Derivatives

    Institute of Scientific and Technical Information of China (English)

    LI Zhi-Feng; ZHU Yuan-Cheng; YUAN Kun; KANG Jing-Wan

    2008-01-01

    The structures of 2,7'-(ethylene)-bis-8-hydroxyquinoline and its derivatives were optimized at the ground states using ab initio HF and B3LYP methods. At the same time, the molecular structures of the first singlet excited state for 2,7'-(ethylene)-bis-8-hydroxyquinoline and its derivatives were optimized by CIS/6-31G(d). The absorption and emission spectra based on the above structures were obtained by the time-dependent density functional theory (TD-DFT) by the B3LYP method with the 6-31G(d) basis set. The calculated results of luminescence originate from the electronic transition from the hydroxphenol ring of 8-hydroxyquinoline A to the pyridine ring of 8-hydroxyquinoline B. Their luminescence wave bands can be tuned by different substituents on the ligand of 8-hydroxyquinoline.

  3. Photon up-conversion increases biomass yield in Chlorella vulgaris.

    Science.gov (United States)

    Menon, Kavya R; Jose, Steffi; Suraishkumar, Gadi K

    2014-12-01

    Photon up-conversion, a process whereby lower energy radiations are converted to higher energy levels via the use of appropriate phosphor systems, was employed as a novel strategy for improving microalgal growth and lipid productivity. Photon up-conversion enables the utilization of regions of the solar spectrum, beyond the typical photosynthetically active radiation, that are usually wasted or are damaging to the algae. The effects of up-conversion of red light by two distinct sets of up-conversion phosphors were studied in the model microalgae Chlorella vulgaris. Up-conversion by set 1 phosphors led to a 2.85 fold increase in biomass concentration and a 3.2 fold increase in specific growth rate of the microalgae. While up-conversion by set 2 phosphors resulted in a 30% increase in biomass and 12% increase in specific intracellular neutral lipid, while the specific growth rates were comparable to that of the control. Furthermore, up-conversion resulted in higher levels of specific intracellular reactive oxygen species in C. vulgaris. Up-conversion of red light (654 nm) was shown to improve biomass yields in C. vulgaris. In principle, up-conversion can be used to increase the utilization range of the electromagnetic spectrum for improved cultivation of photosynthetic systems such as plants, algae, and microalgae.

  4. Digital electronics

    CERN Document Server

    Morris, John

    2013-01-01

    An essential companion to John C Morris's 'Analogue Electronics', this clear and accessible text is designed for electronics students, teachers and enthusiasts who already have a basic understanding of electronics, and who wish to develop their knowledge of digital techniques and applications. Employing a discovery-based approach, the author covers fundamental theory before going on to develop an appreciation of logic networks, integrated circuit applications and analogue-digital conversion. A section on digital fault finding and useful ic data sheets completes th

  5. The Conversation Class

    Science.gov (United States)

    Jackson, Acy L.

    2012-01-01

    The conversation class occupies a unique place in the process of learning English as a second or foreign language. From the author's own experience in conducting special conversation classes with Persian-speaking adults, he has drawn up a number of simple but important guidelines, some of which he hopes may provide helpful suggestions for the…

  6. Content for Conversation Partners.

    Science.gov (United States)

    Olson, Kathleen

    2002-01-01

    Suggests that a good strategy for helping English language learners to develop communicative competence in English is by pairing them with native English speakers. In such conversation programs, conversation partners should be provided with topics and activities that incorporate the goals, interests, and experiences of the learners. Recommends…

  7. Canning Canned Conversations.

    Science.gov (United States)

    Gilmore, Michael P.; Daigaku, Sanyo

    Ways to improve the role-playing conversations found in most second language textbooks are outlined. It is argued that the conversations are often restrictive, dull, and repetitive, and students respond to them in kind. The teacher can make the target language used more interesting by creating new characters, situations, settings, or objectives.…

  8. Hydrothermal conversion of biomass

    NARCIS (Netherlands)

    Knezevic, Dragan

    2009-01-01

    This thesis presents research of hydrothermal conversion of biomass (HTC). In this process, hot compressed water (subcritical water) is used as the reaction medium. Therefore this technique is suitable for conversion of wet biomass/ waste streams. By working at high pressures, the evaporation of wat

  9. Down-conversion photoluminescence sensitizing plasmonic silver nanoparticles on ZnO nanorods to generate hydrogen by water splitting photochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Kung, Po-Yen; Huang, Li-Wen; Shen, Tin-Wei; Wang, Wen-Lin; Su, Yen-Hsun [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan (China); Lin, Melody I. [Department of Physics, University of California, Berkeley, California, 94720 (United States)

    2015-01-12

    Silver nanoparticles fabricated onto the surface of the ZnO nanorods form the photoanode and generate photoelectric current due to surface plasmon resonance, which serves as anode electrodes in photoelectrochemical hydrogen production. In order to increase the absorption spectrum of photoanode, organic pigments were utilized as photo-sensitizers to generate down-conversion photoluminescence to excite surface plasmon resonances of silver nanoparticles. The way of using light to carry the energy in electronic scattering regime runs the system for the enhancement of solar water splitting efficiency. It was significantly tuned in environmentally sustainable applications for power generation and development of alternative energy.

  10. Predictability of conversation partners

    CERN Document Server

    Takaguchi, Taro; Sato, Nobuo; Yano, Kazuo; Masuda, Naoki

    2011-01-01

    Recent developments in sensing technologies have enabled us to examine the nature of human social behavior in greater detail. By applying an information theoretic method to the spatiotemporal data of cell-phone locations, Song et al. (2010) found that human mobility patterns are remarkably predictable. Inspired by their work, we address a similar predictability question in a different kind of human social activity: conversation events. The predictability in the sequence of one's conversation partners is defined as the degree to which one's next conversation partner can be predicted given the current partner. We quantify this predictability by using the mutual information. We examine the predictability of conversation events for each individual using the longitudinal data of face-to-face interactions collected from two company offices in Japan. Each subject wears a name tag equipped with an infrared sensor node, and conversation events are marked when signals are exchanged between close sensor nodes. We find t...

  11. Political conversations on Facebook

    DEFF Research Database (Denmark)

    Sørensen, Mads P.

    2016-01-01

    Political conversations are according to theories on deliberative democracy essential to well-functioning democracies. Traditionally these conversations have taken place in face-to-face settings, in e.g. party meetings and town meetings. However, social media such as Facebook and Twitter offers new...... possibilities for online political conversations between citizens and politicians. This paper examines the presence on Facebook and Twitter of Members of the Danish national Parliament, the Folketing, and focusses on a quantitative mapping of the political conversation activities taking place in the threads...... following Facebook posts from Danish Members of Parliament (MPs). The paper shows that, in comparison with previous findings from other countries, Danish MPs have a relatively high degree of engagement in political conversations with citizens on Facebook – and that a large number of citizens follow MPs...

  12. Spectrum Trading for Efficient Spectrum Utilization

    Directory of Open Access Journals (Sweden)

    Cong Xiong

    2014-04-01

    Full Text Available The conventional command and control based spectrum management has led to substantial underutilization of some spectrum bands while severely crowding others due to the uneven and dynamic needs that vary over time and at different locations. Spectrum trading has emerged as a promising management approach to substantially improve spectrum utilization and user experience in wireless communications by taking advantage of market-based mechanisms. This article presents an overview of spectrum trading, including the fundamental characteristics of spectrum trading markets, the state-of-the-art techniques for modeling and resolving various spectrum trading issues, and trading based dynamic spectrum sharing and access. Moreover, some open issues in spectrum trading are identified for future research in this area.

  13. Radial Basis Function Networks for Conversion of Sound Spectra

    Directory of Open Access Journals (Sweden)

    Carlo Drioli

    2001-03-01

    Full Text Available In many advanced signal processing tasks, such as pitch shifting, voice conversion or sound synthesis, accurate spectral processing is required. Here, the use of Radial Basis Function Networks (RBFN is proposed for the modeling of the spectral changes (or conversions related to the control of important sound parameters, such as pitch or intensity. The identification of such conversion functions is based on a procedure which learns the shape of the conversion from few couples of target spectra from a data set. The generalization properties of RBFNs provides for interpolation with respect to the pitch range. In the construction of the training set, mel-cepstral encoding of the spectrum is used to catch the perceptually most relevant spectral changes. Moreover, a singular value decomposition (SVD approach is used to reduce the dimension of conversion functions. The RBFN conversion functions introduced are characterized by a perceptually-based fast training procedure, desirable interpolation properties and computational efficiency.

  14. 47 CFR 101.521 - Spectrum utilization.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Spectrum utilization. 101.521 Section 101.521 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES 24 GHz Service and Digital Electronic Message Service § 101.521 Spectrum utilization. All...

  15. Uranium conversion; Urankonvertering

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina [Swedish Defence Research Agency (FOI), Stockholm (Sweden)

    2006-03-15

    FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF{sub 6} and UF{sub 4} are present require equipment that is made of corrosion resistant material.

  16. Neutrino Conversions in a Polarized Medium

    CERN Document Server

    Nunokawa, H; Smirnov, Yu A; Valle, José W F

    1997-01-01

    Electron polarization induced by magnetic fields can modify the potentials relevant for describing neutrino conversions in media with magnetic fields. The magnitudes of polarization potentials are determined for different conditions. We show that variations of the electron polarization along the neutrino trajectory can induce resonant conversions in the active-sterile neutrino system, but cannot lead to level crossing in the active-active neutrino system. For neutrino flavour conversions the polarisation leads only to a shift of the standard MSW resonance. For polarizations $\\lambda \\lsim 0.04$ the direct modifications of the potential (density) due to the magnetic field pressure are smaller than the modifications due to the polarization effect. We estimate that indeed the typical magnitude of the polarization in the sun or in a supernova are not expected to exceed $10^{-2}$. However even such a small polarization may lead to interesting consequences for supernova physics and for properties of neutrino signal...

  17. Uranium Conversion & Enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-06

    The isotopes of uranium that are found in nature, and hence in ‘fresh’ Yellowcake’, are not in relative proportions that are suitable for power or weapons applications. The goal of conversion then is to transform the U3O8 yellowcake into UF6. Conversion and enrichment of uranium is usually required to obtain material with enough 235U to be usable as fuel in a reactor or weapon. The cost, size, and complexity of practical conversion and enrichment facilities aid in nonproliferation by design.

  18. Solar energy conversion systems

    CERN Document Server

    Brownson, Jeffrey R S

    2013-01-01

    Solar energy conversion requires a different mind-set from traditional energy engineering in order to assess distribution, scales of use, systems design, predictive economic models for fluctuating solar resources, and planning to address transient cycles and social adoption. Solar Energy Conversion Systems examines solar energy conversion as an integrative design process, applying systems thinking methods to a solid knowledge base for creators of solar energy systems. This approach permits different levels of access for the emerging broad audience of scientists, engineers, architects, planners

  19. A Model for Conversation

    DEFF Research Database (Denmark)

    Ayres, Phil

    2012-01-01

    This essay discusses models. It examines what models are, the roles models perform and suggests various intentions that underlie their construction and use. It discusses how models act as a conversational partner, and how they support various forms of conversation within the conversational activity...... of design. Three distinctions are drawn through which to develop this discussion of models in an architectural context. An examination of these distinctions serves to nuance particular characteristics and roles of models, the modelling activity itself and those engaged in it....

  20. Energy conversion statics

    CERN Document Server

    Messerle, H K; Declaris, Nicholas

    2013-01-01

    Energy Conversion Statics deals with equilibrium situations and processes linking equilibrium states. A development of the basic theory of energy conversion statics and its applications is presented. In the applications the emphasis is on processes involving electrical energy. The text commences by introducing the general concept of energy with a survey of primary and secondary energy forms, their availability, and use. The second chapter presents the basic laws of energy conversion. Four postulates defining the overall range of applicability of the general theory are set out, demonstrating th

  1. Postoperative conversion disorder.

    Science.gov (United States)

    Afolabi, Kola; Ali, Sameer; Gahtan, Vivian; Gorji, Reza; Li, Fenghua; Nussmeier, Nancy A

    2016-05-01

    Conversion disorder is a psychiatric disorder in which psychological stress causes neurologic deficits. A 28-year-old female surgical patient had uneventful general anesthesia and emergence but developed conversion disorder 1 hour postoperatively. She reported difficulty speaking, right-hand numbness and weakness, and right-leg paralysis. Neurologic examination and imaging revealed no neuronal damage, herniation, hemorrhage, or stroke. The patient mentioned failing examinations the day before surgery and discontinuing her prescribed antidepressant medication, leading us to diagnose conversion disorder, with eventual confirmation by neuroimaging and follow-up examinations. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Explorations of Novel Energy Conversion and Storage Systems

    Science.gov (United States)

    Duffin, Andrew Mark

    . As a result, liquid microjets yield conversion efficiencies exceeding 10%, much larger than channel-dependent measurements (˜3%). It is the large potentials obtainable with electrokinetic currents (tens of kilovolts) that drive up the electrical conversion efficiency. Unfortunately, low currents with high voltages are inconvenient for application. Section 3 of Chapter 2 describes efforts to utilize the high voltage of electrokinetic currents by coupling light into the process. More specifically, the streaming potential is used to modify the space charge layer in a semiconductor and, consequently, the light harvesting characteristics of that semiconductor. To this end, microchannel jets fabricated out of glass and silicon were built to allow light to impinge on the current generating surface. Although plagued with inconsistent results, streaming currents were found to increase upon illumination and some channels even gave measurable responses to ambient room lights. Chapter 3 of this dissertation addresses the details of hydration of boron-oxides and sodium borohydride as studied by near edge x-ray absorption fine structure spectroscopy (NEXAFS) and associated theory. Boron-oxides and molecular hydrogen are products of borohydride hydrolysis which has been intensely studied for hydrogen storage purposes. In spite of their hydroxide moieties, boron-oxides turn out to not be strongly hydrated by water. The experimental spectra, as well as attending calculations, show no evidence for electronic coupling that would indicate strong hydrogen bonding between the boron-oxides and water. On the other hand, the NEXAFS spectrum of sodium borohydride is significantly altered by water. The experiment and calculations show strong evidence for short dihydrogen bonds between water hydrogens and borohydride hydrogens. Molecular dynamics simulations indicate that borohydride is hydrated at the tetrahedral corners and edge.

  3. A Conversation about Professionalism and Community.

    Science.gov (United States)

    Bauch, Patricia A.; Crowson, Robert L.; Goldring, Ellen B.; Mawhinney, Hanne B.; Ogawa, Rodney T.; Driscoll, Mary Erina

    1998-01-01

    Presents an interactive electronic conversation among a group of scholars. Participants examined the nature of relationships between professionals and school communities and debated the degree to which conflict was either inevitable or useful in sustaining this connection. They tried to imagine the organizational structures and policies needed to…

  4. Mixed Magnetism for Refrigeration and Energy Conversion

    NARCIS (Netherlands)

    Dung, Nguyen H.; Ou, Zhi Qiang; Caron, Luana; Zhang, Lian; Cam Thanh, Dinh T.; Wijs, Gilles A. de; Groot, Rob A. de; Buschow, K.H. Jürgen; Brück, Ekkes

    2011-01-01

    The efficient coupling between lattice degrees of freedom and spin degrees of freedom in magnetic materials can be used for refrigeration and energy conversion. This coupling is enhanced in materials exhibiting the giant magnetocaloric effect. First principle electronic structure calculations on hex

  5. The Conversion of CESR to Operate as the Test Accelerator, CesrTA, Part 4: Superconducting Wiggler Diagnostics

    CERN Document Server

    Billing, M G; Liu, X; Li, Y; Sabol, D; Smith, E N; Strohman, C R; Palmer, M A; Munson, D V

    2016-01-01

    Cornell's electron/positron storage ring (CESR) was modified over a series of accelerator shutdowns beginning in May 2008, which substantially improves its capability for research and development for particle accelerators. CESR's energy span from 1.8 to 5.6 GeV with both electrons and positrons makes it appropriate for the study of a wide spectrum of accelerator physics issues and instrumentation related to present light sources and future lepton damping rings. Additionally a number of these are also relevant for the beam physics of proton accelerators. This paper, the last in a series of four, describes the vacuum system modifications of the superconducting wigglers to accommodate the diagnostic instrumentation for the study of electron cloud (EC) behavior within wigglers. Earlier papers provided an overview of the accelerator physics program, the general modifications of CESR, the modifications of the vacuum system necessary for the conversion of CESR to the test accelerator, CesrTA, enhanced to study such ...

  6. Microturbine Power Conversion Technology Review

    Energy Technology Data Exchange (ETDEWEB)

    Staunton, R.H.

    2003-07-21

    In this study, the Oak Ridge National Laboratory (ORNL) is performing a technology review to assess the market for commercially available power electronic converters that can be used to connect microturbines to either the electric grid or local loads. The intent of the review is to facilitate an assessment of the present status of marketed power conversion technology to determine how versatile the designs are for potentially providing different services to the grid based on changes in market direction, new industry standards, and the critical needs of the local service provider. The project includes data gathering efforts and documentation of the state-of-the-art design approaches that are being used by microturbine manufacturers in their power conversion electronics development and refinement. This project task entails a review of power converters used in microturbines sized between 20 kW and 1 MW. The power converters permit microturbine generators, with their non-synchronous, high frequency output, to interface with the grid or local loads. The power converters produce 50- to 60-Hz power that can be used for local loads or, using interface electronics, synchronized for connection to the local feeder and/or microgrid. The power electronics enable operation in a stand-alone mode as a voltage source or in grid-connect mode as a current source. Some microturbines are designed to automatically switch between the two modes. The information obtained in this data gathering effort will provide a basis for determining how close the microturbine industry is to providing services such as voltage regulation, combined control of both voltage and current, fast/seamless mode transfers, enhanced reliability, reduced cost converters, reactive power supply, power quality, and other ancillary services. Some power quality improvements will require the addition of storage devices; therefore, the task should also determine what must be done to enable the power conversion circuits to

  7. Photon and electron identification with the ATLAS detector

    CERN Document Server

    Cerda Alberich, Leonor; The ATLAS collaboration

    2016-01-01

    Photon and electron identifications are a crucial input to many ATLAS physics analysis. The identification of prompt photons and the rejection of background coming mostly from photons from hadron decays relies on the high granularity of the ATLAS calorimeter. The electron identification used in ATLAS for run 2 is based on a likelihood discrimination combining calorimeter and track variables to separate isolated electron candidates from candidates originating from photon conversions, hadron misidentification and heavy flavor decays. In addition, isolation variables are used as further handles to separate signal and background. Several methods are used to measure with data the efficiency of the photon identification requirements, to cover a broad energy spectrum. At low energy, photons from radiative Z decays are used. In the medium energy range, similarities between electrons and photon showers are exploited using Z->ee decays. At high energy, inclusive photon samples are used. The measurement of the efficienc...

  8. Structured luminescence conversion layer

    Science.gov (United States)

    Berben, Dirk; Antoniadis, Homer; Jermann, Frank; Krummacher, Benjamin Claus; Von Malm, Norwin; Zachau, Martin

    2012-12-11

    An apparatus device such as a light source is disclosed which has an OLED device and a structured luminescence conversion layer deposited on the substrate or transparent electrode of said OLED device and on the exterior of said OLED device. The structured luminescence conversion layer contains regions such as color-changing and non-color-changing regions with particular shapes arranged in a particular pattern.

  9. Managing social media conversations

    OpenAIRE

    2015-01-01

    The purpose of this thesis was to explore how companies can manage (monitor and control) social media conversations. Regardless of the companies’ presence in social media networks, they or their industry are constantly being discussed in social media. Therefore organisations should be present in social media, monitor and participate in conversations, in order to turn them into their benefit. There are software and services available to help in monitoring. Variety of tools and statistic de...

  10. γ-Ray polarimetry with conversions to e+e- pairs: Polarization asymmetry and the way to measure it

    Science.gov (United States)

    Gros, P.; Bernard, D.

    2017-02-01

    We revisit the measurement of the polarization fraction, P, and of the polarization angle of partially linearly-polarized gamma rays using their conversion to e+e- pairs in the field of a nucleus. We show that an inappropriate definition of the azimuthal angle, φ, used to reference the orientation of the final state degrades the precision of the measurement of P, by comparison to the optimal case where the bisector angle of the electron and of the positron momenta is used. We then focus on the lowest part of the energy spectrum, below ≈ 10 MeV, where a large part of the statistics lie for a cosmic source. We obtain the value of the polarization asymmetry, A, of pair conversion at threshold and we show that in the case where the correct expression is used for φ, the measured value of A tends to the limit.

  11. $\\gamma$-ray polarimetry with conversions to $e^+e^-$ pairs: polarization asymmetry and the way to measure it

    CERN Document Server

    Gros, Philippe

    2016-01-01

    We revisit the measurement of the polarization fraction, $P$, and the measurement of the polarization angle of partially linearly-polarized gamma rays using their conversion to $e^+e^-$ pairs in the field of a nucleus. We show that an inappropriate definition of the azimuthal angle, $\\varphi$, used to reference the orientation of the final state degrades the precision of the measurement of $P$, by comparison to the optimal case where the bisector angle of the electron and of the positron momenta is used. We then focus on the lowest part of the energy spectrum, below $\\approx 10\\,$MeV, where a large part of the statistics lie for a cosmic source. We obtain the value of the polarization asymmetry, $A$, of pair conversion at threshold and we show that in the case where the correct expression is used for $\\varphi$, the measured value of $A$ tends to the limit.

  12. Conversational flow promotes solidarity.

    Science.gov (United States)

    Koudenburg, Namkje; Postmes, Tom; Gordijn, Ernestine H

    2013-01-01

    Social interaction is fundamental to the development of various aspects of "we-ness". Previous research has focused on the role the content of interaction plays in establishing feelings of unity, belongingness and shared reality (a cluster of variables referred to as solidarity here). The present paper is less concerned with content, but focuses on the form of social interaction. We propose that the degree to which conversations flow smoothly or not is, of itself, a cue to solidarity. We test this hypothesis in samples of unacquainted and acquainted dyads who communicate via headsets. Conversational flow is disrupted by introducing a delay in the auditory feedback (vs. no delay). Results of three studies show that smoothly coordinated conversations (compared with disrupted conversations and a control condition) increase feelings of belonging and perceptions of group entitativity, independently of conversation content. These effects are driven by the subjective experience of conversational flow. Our data suggest that this process occurs largely beyond individuals' control. We conclude that the form of social interaction is a powerful cue for inferring group solidarity. Implications for the impact of modern communication technology on developing a shared social identity are discussed.

  13. Conversational flow promotes solidarity.

    Directory of Open Access Journals (Sweden)

    Namkje Koudenburg

    Full Text Available Social interaction is fundamental to the development of various aspects of "we-ness". Previous research has focused on the role the content of interaction plays in establishing feelings of unity, belongingness and shared reality (a cluster of variables referred to as solidarity here. The present paper is less concerned with content, but focuses on the form of social interaction. We propose that the degree to which conversations flow smoothly or not is, of itself, a cue to solidarity. We test this hypothesis in samples of unacquainted and acquainted dyads who communicate via headsets. Conversational flow is disrupted by introducing a delay in the auditory feedback (vs. no delay. Results of three studies show that smoothly coordinated conversations (compared with disrupted conversations and a control condition increase feelings of belonging and perceptions of group entitativity, independently of conversation content. These effects are driven by the subjective experience of conversational flow. Our data suggest that this process occurs largely beyond individuals' control. We conclude that the form of social interaction is a powerful cue for inferring group solidarity. Implications for the impact of modern communication technology on developing a shared social identity are discussed.

  14. Programming-Free Form Conversion, Design, and Processing

    OpenAIRE

    Fan, Ting-Jun; Machlin, Rona S.; Wang, Christopher P.; Chang, Ifay F.

    1990-01-01

    In this paper, we present the requirements and design considerations for programming-free form conversion, design, and processing. A set of object-oriented software tools are also presented to help users convert a paper form into an electronic form, design an electronic form, and fill in an electronic form directly on screen.

  15. Device structure for OLED light device having multi element light extraction and luminescence conversion layer

    Science.gov (United States)

    Antoniadis; Homer , Krummacher; Benjamin Claus

    2008-01-22

    An apparatus such as a light source has a multi-element light extraction and luminescence conversion layer disposed over a transparent layer of the light source and on the exterior of said light source. The multi-element light extraction and luminescence conversion layer includes a plurality of light extraction elements and a plurality of luminescence conversion elements. The light extraction elements diffuses the light from the light source while luminescence conversion elements absorbs a first spectrum of light from said light source and emits a second spectrum of light.

  16. OLED lighting devices having multi element light extraction and luminescence conversion layer

    Science.gov (United States)

    Krummacher, Benjamin Claus; Antoniadis, Homer

    2010-11-16

    An apparatus such as a light source has a multi element light extraction and luminescence conversion layer disposed over a transparent layer of the light source and on the exterior of said light source. The multi-element light extraction and luminescence conversion layer includes a plurality of light extraction elements and a plurality of luminescence conversion elements. The light extraction elements diffuses the light from the light source while luminescence conversion elements absorbs a first spectrum of light from said light source and emits a second spectrum of light.

  17. Solar PV Energy Conversion System and its Configurations

    OpenAIRE

    Ahteshamul Haque

    2016-01-01

    Solar PV based energy conversion system is now used in commercial and residential buildings. Advancements in Power electronics leads the researchers to enhance the use of solar application in various configurations. These configurations may be used to utilize the energy optimally. The main objective of this paper is to present an overview of the various configurations of solar PV energy conversion system

  18. Boiler conversions for biomass

    Energy Technology Data Exchange (ETDEWEB)

    Kinni, J. [Tampella Power Inc., Tampere (Finland)

    1996-12-31

    Boiler conversions from grate- and oil-fired boilers to bubbling fluidized bed combustion have been most common in pulp and paper industry. Water treatment sludge combustion, need for additional capacity and tightened emission limits have been the driving forces for the conversion. To accomplish a boiler conversion for biofuel, the lower part of the boiler is replaced with a fluidized bed bottom and new fuel, ash and air systems are added. The Imatran Voima Rauhalahti pulverized-peat-fired boiler was converted to bubbling fluidized bed firing in 1993. In the conversion the boiler capacity was increased by 10 % to 295 MWth and NO{sub x} emissions dropped. In the Kymmene Kuusankoski boiler, the reason for conversion was the combustion of high chlorine content biosludge. The emissions have been under general European limits. During the next years, the emission limits will tighten and the boilers will be designed for most complete combustion and compounds, which can be removed from flue gases, will be taken care of after the boiler. (orig.) 3 refs.

  19. Seyfert 1 composite spectrum using SDSS Legacy survey data

    Science.gov (United States)

    Pol, Nihan; Wadadekar, Yogesh

    2017-02-01

    We present a rest-frame composite spectrum for Seyfert 1 galaxies using spectra obtained from the 12th Data Release of the Sloan Digital Sky Survey. The spectrum is constructed by combining data from a total of 10112 galaxies, spanning a redshift range of 0-0.793. We produce an electronic table of the median and geometric mean composite Seyfert 1 spectrum. We measure the spectral index of the composite spectrum, and compare it with that of the composite quasar spectrum. We also measure the flux and width of the strong emission lines present in the composite spectrum. We compare the entire spectrum with the quasar spectrum in the context of the unification model for active galactic nuclei. The two composite spectra match extremely well in the blue part of the spectrum, while there is an offset in flux in the red portion of the spectrum.

  20. Photovoltaic solar energy conversion

    CERN Document Server

    Bauer, Gottfried H

    2015-01-01

    This concise primer on photovoltaic solar energy conversion invites readers to reflect on the conversion of solar light into energy at the most fundamental level and encourages newcomers to the field to help find meaningful answers on how photovoltaic solar energy conversion can work (better), eventually contributing to its ongoing advancement. The book is based on lectures given to graduate students in the Physics Department at the University of Oldenburg over the last two decades, yet also provides an easy-to-follow introduction for doctoral and postdoctoral students from related disciplines such as the materials sciences and electrical engineering. Inspired by classic textbooks in the field, it reflects the author’s own ideas on how to understand, visualize and eventually teach the microscopic physical mechanisms and effects, while keeping the text as concise as possible so as to introduce interested readers to the field and balancing essential knowledge with open questions.

  1. Direct conversion technology

    Energy Technology Data Exchange (ETDEWEB)

    Massier, P.F.; Back, L.H.; Ryan, M.A.; Fabris, G.

    1992-01-07

    The overall objective of the Direct Conversion Technology task is to develop an experimentally verified technology base for promising direct conversion systems that have potential application for energy conservation in the end-use sectors. This report contains progress of research on the Alkali Metal Thermal-to-Electric Converter (AMTEC) and on the Two-Phase Liquid-Metal MHD Electrical Generator (LMMHD) for the period January 1, 1991 through December 31, 1991. Research on AMTEC and on LMMHD was initiated during October 1987. Reports prepared on previous occasions (Refs. 1--5) contain descriptive and performance discussions of the following direct conversion concepts: thermoelectric, pyroelectric, thermionic, thermophotovoltaic, thermoacoustic, thermomagnetic, thermoelastic (Nitionol heat engine); and also, more complete descriptive discussions of AMTEC and LMMHD systems.

  2. Freely flowing conversations

    DEFF Research Database (Denmark)

    Aakjær, Marie Kirstejn; Andrade, David; Dexters, Peter

    2012-01-01

    on - and support “positive deviants” (Pascal, Sternin and Sternin) – courageous individuals and groups (inmates as well as staff) who transform conversations into new actions and behavioral traits that become beckons of an improved future. In the following we explore concrete examples of efforts at improving......Some would say this article is an impossibility - the authors being a project manager from the Department of Prisons an (ex) inmate and a Designer doing an industrial PhD in the prisons. We hope that others may see this article as an embodiment of how taking part in new conversations...... and in regards to rehabilitation efforts. In the context of prisons UDI is inspired by the complexity approach (Stacey 2005). We seek to facilitate freely flowing conversations between inmates, staff and managers – pushing the boundaries of existing norms, roles and beliefs. In the end however we rely...

  3. Predictability of Conversation Partners

    Science.gov (United States)

    Takaguchi, Taro; Nakamura, Mitsuhiro; Sato, Nobuo; Yano, Kazuo; Masuda, Naoki

    2011-08-01

    Recent developments in sensing technologies have enabled us to examine the nature of human social behavior in greater detail. By applying an information-theoretic method to the spatiotemporal data of cell-phone locations, [C. Song , ScienceSCIEAS0036-8075 327, 1018 (2010)] found that human mobility patterns are remarkably predictable. Inspired by their work, we address a similar predictability question in a different kind of human social activity: conversation events. The predictability in the sequence of one’s conversation partners is defined as the degree to which one’s next conversation partner can be predicted given the current partner. We quantify this predictability by using the mutual information. We examine the predictability of conversation events for each individual using the longitudinal data of face-to-face interactions collected from two company offices in Japan. Each subject wears a name tag equipped with an infrared sensor node, and conversation events are marked when signals are exchanged between sensor nodes in close proximity. We find that the conversation events are predictable to a certain extent; knowing the current partner decreases the uncertainty about the next partner by 28.4% on average. Much of the predictability is explained by long-tailed distributions of interevent intervals. However, a predictability also exists in the data, apart from the contribution of their long-tailed nature. In addition, an individual’s predictability is correlated with the position of the individual in the static social network derived from the data. Individuals confined in a community—in the sense of an abundance of surrounding triangles—tend to have low predictability, and those bridging different communities tend to have high predictability.

  4. Nuclear conversion theory: molecular hydrogen in non-magnetic insulators

    Science.gov (United States)

    Ilisca, Ernest; Ghiglieno, Filippo

    2016-09-01

    The hydrogen conversion patterns on non-magnetic solids sensitively depend upon the degree of singlet/triplet mixing in the intermediates of the catalytic reaction. Three main `symmetry-breaking' interactions are brought together. In a typical channel, the electron spin-orbit (SO) couplings introduce some magnetic excitations in the non-magnetic solid ground state. The electron spin is exchanged with a molecular one by the electric molecule-solid electron repulsion, mixing the bonding and antibonding states and affecting the molecule rotation. Finally, the magnetic hyperfine contact transfers the electron spin angular momentum to the nuclei. Two families of channels are considered and a simple criterion based on the SO coupling strength is proposed to select the most efficient one. The denoted `electronic' conversion path involves an emission of excitons that propagate and disintegrate in the bulk. In the other denoted `nuclear', the excited electron states are transients of a loop, and the electron system returns to its fundamental ground state. The described model enlarges previous studies by extending the electron basis to charge-transfer states and `continui' of band states, and focuses on the broadening of the antibonding molecular excited state by the solid conduction band that provides efficient tunnelling paths for the hydrogen conversion. After working out the general conversion algebra, the conversion rates of hydrogen on insulating and semiconductor solids are related to a few molecule-solid parameters (gap width, ionization and affinity potentials) and compared with experimental measures.

  5. Converse Barrier Certificate Theorem

    DEFF Research Database (Denmark)

    Wisniewski, Rafael; Sloth, Christoffer

    2013-01-01

    This paper presents a converse barrier certificate theorem for a generic dynamical system.We show that a barrier certificate exists for any safe dynamical system defined on a compact manifold. Other authors have developed a related result, by assuming that the dynamical system has no singular...... points in the considered subset of the state space. In this paper, we redefine the standard notion of safety to comply with generic dynamical systems with multiple singularities. Afterwards, we prove the converse barrier certificate theorem and illustrate the differences between ours and previous work...

  6. Ocean wave energy conversion

    CERN Document Server

    McCormick, Michael E

    2007-01-01

    This volume will prove of vital interest to those studying the use of renewable resources. Scientists, engineers, and inventors will find it a valuable review of ocean wave mechanics as well as an introduction to wave energy conversion. It presents physical and mathematical descriptions of the nine generic wave energy conversion techniques, along with their uses and performance characteristics.Author Michael E. McCormick is the Corbin A. McNeill Professor of Naval Engineering at the U.S. Naval Academy. In addition to his timely and significant coverage of possible environmental effects associa

  7. Virtual conversation partner for adults with autism.

    Science.gov (United States)

    Trepagnier, Cheryl Y; Olsen, Dale E; Boteler, Laura; Bell, Corinne A

    2011-01-01

    Autistic Spectrum Disorder (ASD) is notable for severely impaired reciprocal social interaction skills relative to language and intellectual abilities, presenting a major barrier to social integration and vocational success. Evidence-based interventions to address these needs are lacking. We report on the development of a small, prototype conversation simulation to teach conversational skills to adolescents and adults with ASD and average to superior intellectual abilities. We also report on a test of the feasibility and acceptability of the simulation approach with a sample of the target population. The simulation engages the user in a virtual conversation with an on-screen partner whose reactions provide naturalistic feedback geared to the appropriateness of the learner's response choices. The prototype simulation, which provides for up to 12 potentially unique multi-turn conversations, was used over a period of 2 weeks by 16 adolescents and adults who then rated statements about the system on a linear scale of 1 (disagreement) to 5 (high agreement). The participants highly endorsed the majority of positive statements about the quality and credibility of the interaction and the virtual conversation partner. In contrast, agreement with positive statements about instructional features external to the conversation was moderate. Unexpectedly, most participants strongly agreed that using the simulation had been helpful to them. Further development and testing in the context of a controlled study with randomized assignment to control and experimental groups are needed to determine whether this approach is effective in improving real-world pragmatic language behavior of high-functioning adults with ASD.

  8. AN IMPROVED ALGORITHM OF GMM VOICE CONVERSION SYSTEM BASED ON CHANGING THE TIME-SCALE

    Institute of Scientific and Technical Information of China (English)

    Zhou Ying; Zhang Linghua

    2011-01-01

    This paper improves and presents an advanced method of the voice conversion system based on Gaussian Mixture Models (GMM) models by changing the time-scale of speech.The Speech Transformation and Representation using Adaptive Interpolation of weiGHTed spectrum (STRAIGHT) model is adopted to extract the spectrum features,and the GMM models are trained to generate the conversion function.The spectrum features of a source speech will be converted by the conversion function.The time-scale of speech is changed by extracting the converted features and adding to the spectrum.The conversion voice was evaluated by subjective and objective measurements.The results confirm that the transformed speech not only approximates the characteristics of the target speaker,but also more natural and more intelligible.

  9. Tm2+ luminescent materials for solar radiation conversion devices

    NARCIS (Netherlands)

    Van der Kolk, E.

    2015-01-01

    A solar radiation conversion device is described that comprises a luminescent Tm 2+ inorganic material for converting solar radiation of at least part of the UV and/or visible and/or infra red solar spectrum into infrared solar radiation, preferably said infrared solar radiation having a wavelength

  10. Towards improved photovoltaic conversion using dilute magnetic semiconductors (abstract only)

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, Paer [IRDEP, UMR-7174 CNRS/EDF/ENSCP, 6 quai Waitier, F-78401 Chatou (France); Guillemoles, J-F [IRDEP, UMR-7174 CNRS/EDF/ENSCP, 6 quai Waitier, F-78401 Chatou (France); Domain, C [IRDEP, UMR-7174 CNRS/EDF/ENSCP, 6 quai Waitier, F-78401 Chatou (France)

    2008-02-13

    Present photovoltaic devices, based on p/n junctions, are limited from first principles to maximal efficiencies of 31% (40% under full solar concentration; Shockley and Queisser 1961 J. Appl. Phys. 32 510). However, more innovative schemes may overcome the Shockley-Queisser limit since the theoretical maximal efficiency of solar energy conversion is higher than 85% (Harder and Wuerfel 2003 Semicond. Sci. Technol. 18 S151). To date, the only practical realization of such an innovative scheme has been multi-junction devices, which at present hold the world record for efficiency at nearly 41% at significant solar concentration (US DOE news site: http://www.energy.gov/news/4503.htm). It has been proposed that one could make use of the solar spectrum in much the same way as the multi-junction devices do but in a single cell, using impurity induced intermediate levels to create gaps of different sizes. This intermediate level semiconductor (ILSC) concept (Green and Wenham 1994 Appl. Phys. Lett. 65 2907; Luque and MartI1997 Phys. Rev. Lett. 78 5014) has a maximal efficiency similar to that of multi-junction devices but suffers from prohibitively large non-radiative recombination rates. We here propose to use a ferromagnetic impurity scheme in order to reduce the non-radiative recombination rates while maintaining the high theoretical maximum efficiency of the ILSC scheme, that is about 46%. Using density functional theory calculations, the electronic and energetic properties of transition metal impurities for a wide range of semiconductors have been analysed. Of the several hundred compounds studied, only a few fulfil the design criteria that we present here. As an example, wide gap AlP is one of the most promising compounds. It was found that inclusion of significant amounts of Mn in AlP induces band structures providing conversion efficiencies potentially close to the theoretical maximum, with an estimated Curie temperature reaching above 100 K.

  11. Gender Differences in Conversation

    Institute of Scientific and Technical Information of China (English)

    陈媛媛

    2014-01-01

    Men and women applied language distinct from each other in many ways. The thesis gives an illustration of gender dif-ferences in conversation and different interpretive frames within which the discourse between men and women take place. More profoundly, it tries to explain them from perspective of socialization.

  12. Predicting AD conversion

    DEFF Research Database (Denmark)

    Liu, Yawu; Mattila, Jussi; Ruiz, Miguel �ngel Mu�oz

    2013-01-01

    To compare the accuracies of predicting AD conversion by using a decision support system (PredictAD tool) and current research criteria of prodromal AD as identified by combinations of episodic memory impairment of hippocampal type and visual assessment of medial temporal lobe atrophy (MTA) on MRI...

  13. Clinical Linguistics: Conversational Reflections

    Science.gov (United States)

    Crystal, David

    2013-01-01

    This is a report of the main points I made in an informal "conversation" with Paul Fletcher and the audience at the 14th ICPLA conference in Cork. The observations arose randomly, as part of an unstructured 1-h Q&A, so they do not provide a systematic account of the subject, but simply reflect the issues which were raised by the conference…

  14. Solar energy conversion

    OpenAIRE

    Crabtree, George W.; Lewis, Nathan S.

    2007-01-01

    If solar energy is to become a practical alternative to fossil fuels, we must have efficient ways to convert photons into electricity, fuel, and heat. The need for better conversion technologies is a driving force behind many recent developments in biology, materials, and especially nanoscience.

  15. Wavelength conversion technology

    DEFF Research Database (Denmark)

    Stubkjær, Kristian

    1998-01-01

    Optical wavelength conversion is currently attracting much interest. This is because it enables full flexibility and eases management of WDM fibre networks. The tutorial will review existing and potential application areas. Examples of node architectures and network demonstrators that use wavelen...

  16. Wavelength conversion devices

    DEFF Research Database (Denmark)

    Mikkelsen, Benny; Durhuus, Terji; Jørgensen, Carsten

    1996-01-01

    system requirements. The ideal wavelength converter should be transparent to the bit rate and signal format and provide an unchirped output signal with both a high extinction ratio and a large signal-to-noise ratio. It should allow conversion to both shorter and longer wavelengths with equal performance...

  17. Dissenting in Reflective Conversations

    DEFF Research Database (Denmark)

    Bjørn, Pernille; Boulus, Nina

    2011-01-01

    a methodological reflective approach that provides space for taking seriously uncertainties experienced in the field as these can be a catalyst for learning and sharpening our theoretical and empirical skills as action researchers. Through first-person inquiry, we investigate how our reflective conversations...

  18. Paralympics and conversion disorder

    National Research Council Canada - National Science Library

    David, Anthony S

    ...' for whose disorders are the most stigmatised. Psychiatry has a strong claim on this with mental illness generally regarded as among the most feared and least understood. 1 And within psychiatry there is a similar hierarchy such that patients with 'hysteria' or conversion disorder (CD) are those found to be least satisfying to treat and are least like...

  19. Leadership is a conversation.

    Science.gov (United States)

    Groysberg, Boris; Slind, Michael

    2012-06-01

    Globalization and new technologies have sharply reduced the efficacy of command-and-control management and its accompanying forms of corporate communication. In the course of a recent research project, the authors concluded that by talking with employees, rather than simply issuing orders, leaders can promote operational flexibility, employee engagement, and tight strategic alignment. Groysberg and Slind have identified four elements of organizational conversation that reflect the essential attributes of interpersonal conversation: intimacy, interactivity, inclusion, and intentionality. Intimacy shifts the focus from a top-down distribution of information to a bottom-up exchange of ideas. Organizational conversation is less corporate in tone and more casual. And it's less about issuing and taking orders than about asking and answering questions. Interactivity entails shunning the simplicity of monologue and embracing the unpredictable vitality of dialogue. Traditional one-way media-print and broadcast, in particular-give way to social media buttressed by social thinking. Inclusion turns employees into full-fledged conversation partners, entitling them to provide their own ideas, often on company channels. They can create content and act as brand ambassadors, thought leaders, and storytellers. Intentionality enables leaders and employees to derive strategically relevant action from the push and pull of discussion and debate.

  20. Converse Barrier Certificate Theorems

    DEFF Research Database (Denmark)

    Wisniewski, Rafael; Sloth, Christoffer

    2016-01-01

    This paper shows that a barrier certificate exists for any safe dynamical system. Specifically, we prove converse barrier certificate theorems for a class of structurally stable dynamical systems. Other authors have developed a related result by assuming that the dynamical system has neither sing...

  1. Conversational English Program, 1.

    Science.gov (United States)

    Instituto de Idiomas Yazigi, Sao Paulo (Brazil). Centro de Linguistica Aplicada.

    This first book of a conversational English program for adults contains an introductory section in Portuguese and exercises in English. The text centers around an English-speaking family from the United States that goes to live in Brazil. It contains color photographs with captions followed by exercises. The exercises are in English and involve…

  2. Conversational English Program, 2.

    Science.gov (United States)

    Instituto de Idiomas Yazigi, Sao Paulo (Brazil). Centro de Linguistica Aplicada.

    This second book of a conversational English program for adults contains an introductory section in Portuguese and exercises in English. The text centers around an English-speaking family from the United States that goes to live in Brazil. It contains color photographs with captions followed by exercises. The exercises are in English and involve…

  3. Organ dose conversions from ESR measurements using tooth enamel of atomic bomb survivors.

    Science.gov (United States)

    Takahashi, Fumiaki; Sato, Kaoru

    2012-03-01

    Dose conversions were studied for dosimetry of atomic bomb survivors based upon electron spin resonance (ESR) measurements of tooth enamel. Previously analysed data had clarified that the tooth enamel dose could be much larger than other organ doses from a low-energy photon exposure. The radiation doses to other organs or whole-body doses, however, are assumed to be near the tooth enamel dose for photon energies which are dominant in the leakage spectrum of the Hiroshima atomic bomb assumed in DS02. In addition, the thyroid can be a candidate for a surrogate organ in cases where the tooth enamel dose is not available in organ dosimetry. This paper also suggests the application of new Japanese voxel phantoms to derive tooth enamel doses by numerical analyses.

  4. Spectral light management for solar energy conversion systems

    Directory of Open Access Journals (Sweden)

    Stanley Cameron

    2016-06-01

    Full Text Available Due to the inherent broadband nature of the solar radiation, combined with the narrow spectral sensitivity range of direct solar to electricity devices, there is a massive opportunity to manipulate the solar spectrum to increase the functionality and efficiency of solar energy conversion devices. Spectral splitting or manipulation facilitates the efficient combination of both high-temperature solar thermal systems, which can absorb over the entire solar spectrum to create heat, and photovoltaic cells, which only convert a range of wavelengths to electricity. It has only recently been possible, with the development of nanofabrication techniques, to integrate micro- and nano-photonic structures as spectrum splitters/manipulators into solar energy conversion devices. In this paper, we summarize the recent developments in beam splitting techniques, and highlight some relevant applications including combined PV-thermal collectors and efficient algae production, and suggest paths for future development in this field.

  5. Spectral light management for solar energy conversion systems

    Science.gov (United States)

    Stanley, Cameron; Mojiri, Ahmad; Rosengarten, Gary

    2016-06-01

    Due to the inherent broadband nature of the solar radiation, combined with the narrow spectral sensitivity range of direct solar to electricity devices, there is a massive opportunity to manipulate the solar spectrum to increase the functionality and efficiency of solar energy conversion devices. Spectral splitting or manipulation facilitates the efficient combination of both high-temperature solar thermal systems, which can absorb over the entire solar spectrum to create heat, and photovoltaic cells, which only convert a range of wavelengths to electricity. It has only recently been possible, with the development of nanofabrication techniques, to integrate micro- and nano-photonic structures as spectrum splitters/manipulators into solar energy conversion devices. In this paper, we summarize the recent developments in beam splitting techniques, and highlight some relevant applications including combined PV-thermal collectors and efficient algae production, and suggest paths for future development in this field.

  6. Seyfert 1 Composite Spectrum using SDSS Legacy Survey Data

    CERN Document Server

    Pol, Nihan

    2016-01-01

    We present a rest-frame composite spectrum for Seyfert 1 galaxies using spectra obtained from the DR12 release of the Sloan Digital Sky Survey (SDSS). The spectrum is constructed by combining data from a total of 10,112 galaxies, spanning a redshift range of 0 to 0.793. We produce an electronic table of the median and geometric mean composite Seyfert 1 spectrum. We measure the spectral index of the composite spec- trum, and compare it with that of the composite quasar spectrum. We also measure the flux and width of the strong emission lines present in the composite spectrum. We compare the entire spectrum with the quasar spectrum in the context of the AGN unification model. The two composite spectra match extremely well in the blue part of the spectrum, while there is an offset in flux in the red portion of the spectrum.

  7. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel J M

    2010-01-01

    The design of an analog-to-digital converter or digital-to-analog converter is one of the most fascinating tasks in micro-electronics. In a converter the analog world with all its intricacies meets the realm of the formal digital abstraction. Both disciplines must be understood for an optimum conversion solution. In a converter also system challenges meet technology opportunities. Modern systems rely on analog-to-digital converters as an essential part of the complex chain to access the physical world. And processors need the ultimate performance of digital-to-analog converters to present the results of their complex algorithms. The same progress in CMOS technology that enables these VLSI digital systems creates new challenges for analog-to-digital converters: lower signal swings, less power and variability issues. Last but not least, the analog-to-digital converter must follow the cost reduction trend. These changing boundary conditions require micro-electronics engineers to consider their design choices for...

  8. Freely flowing conversations

    DEFF Research Database (Denmark)

    Aakjær, Marie Kirstejn; Andrade, David; Dexters, Peter

    2012-01-01

    and relationships may allow us to transcend the barriers of our formal positions. To us it is a testimony of the struggles and the good times we have shared while attempting to improve life in prisons. Also, this is an occasion for reflection on what we have learned from the process. The User Driven Innovation (in...... for guards. It has turned the focus of the organization towards the importance of relationship-building. In 2011 the Director General and the Prison Governors stated that building positive relations is the most important future task for Danish prisons both in regards to improving prison environments...... relations by changing conversations. Through the theoretical framework of the complexity approach, we discuss how this may lead to organizational change. Finally we suggest that inviting inmates to take part in conversations about core organizational development may be a fundamental strategy in trying...

  9. Les conversions de cens

    Directory of Open Access Journals (Sweden)

    Laurent Feller

    2006-09-01

    Full Text Available Dans le cadre d’une recherche entamée sur la circulation des richesses au Moyen Âge, la réflexion s’est dirigée vers la question de la conversion, c’est-à-dire du passage d’une forme à une autre dans la mesure des valeurs (argent contre nature, objets dont l’usage se transforme en s’échangeant, conversions monétaires. Un cycle de trois rencontres est prévu afin de débrouiller une question complexe qui devrait permettre au groupe d’éclairer la question de la valeur des choses au Moyen Âge. La...

  10. Multilayer Film Fabrication and Photoelectric Conversion Property of Two Pyrrolidinofullerene Carboxylic Acid Derivatives

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Two multilayer films of pyrrolidinofullerene carboxylic acid derivatives, which exhibit photoelectric conversion property, are reported here. The first monolayers were fabricated on hydrophilic indium-tin-oxide (ITO), quartz, and mica by esterification reaction. The multilayers were characterized by contact angle and UV spectrum. The photoelectric conversion properties of both multilayer films were studied.

  11. Clinical linguistics: conversational reflections.

    Science.gov (United States)

    Crystal, David

    2013-04-01

    This is a report of the main points I made in an informal "conversation" with Paul Fletcher and the audience at the 14th ICPLA conference in Cork. The observations arose randomly, as part of an unstructured 1-h Q&A, so they do not provide a systematic account of the subject, but simply reflect the issues which were raised by the conference participants during that time.

  12. Conversations with Miss Jane

    Directory of Open Access Journals (Sweden)

    Geneviève Fabre

    2006-05-01

    Full Text Available Considering the wide range of conversations in the autobiography, this essay will attempt to appraise the importance of these verbal exchanges in relation to the overall narrative structure of the book and to the prevalent oral tradition in Louisiana culture, as both an individual and communal expression. The variety of circumstances, the setting and staging, the interlocutors , and the complex intersection of time and place, of stories and History, will be examined; in these conversations with Miss Jane many actors participate, from  the interviewer-narrator, to most characters; even the reader becomes involved.Speaking, hearing, listening, keeping silent is an elaborate ritual that performs many functions; besides conveying news or rumors, it imparts information on the times and on the life of a “representative” woman whose existence - spanning a whole century- is both singular and emblematic. Most importantly this essay will analyse the resonance of an eventful and often dramatic era on her sensibility and conversely show how her evolving sensibility informs that history and draws attention to aspects that might have passed unnoticed or be forever silenced. Jane’s desire for liberty and justice is often challenged as she faces the possibilities of life or death.Conversations build up a complex, often contradictory, but compelling portrait: torn between silence and vehemence, between memories and the urge to meet the future, Jane summons body and mind to find her way through the maze of a fast changing world; self-willed and obstinate she claims her right to speak, to express with wit and wisdom her firm belief in the word, in the ability to express deep seated convictions and faith and a whole array of feelings and emotions.

  13. Natural gas conversion process

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    The experimental apparatus was dismantled and transferred to a laboratory space provided by Lawrence Berkeley Laboratory (LBL) which is already equipped with a high-ventilation fume hood. This will enable us to make tests at higher gas flow rates in a safe environment. Three papers presented at the ACS meeting in San Francisco (Symposium on Natural Gas Upgrading II) April 5--10, 1992 show that the goal of direct catalytic conversion of Methane into heavier Hydrocarbons in a reducing atmosphere is actively pursued in three other different laboratories. There are similarities in their general concept with our own approach, but the temperature range of the experiments reported in these recent papers is much lower and this leads to uneconomic conversion rates. This illustrates the advantages of Methane activation by a Hydrogen plasma to reach commercial conversion rates. A preliminary process flow diagram was established for the Integrated Process, which was outlined in the previous Quarterly Report. The flow diagram also includes all the required auxiliary facilities for product separation and recycle of the unconverted feed as well as for the preparation and compression of the Syngas by-product.

  14. A Review of Power Electronics for Wind Power

    DEFF Research Database (Denmark)

    Chen, Zhe

    2011-01-01

    The paper reviews the power electronic applications for wind energy systems. Main wind turbine systems with different generators and power electronic converters are described. The electrical topologies of wind farms with power electronic conversion are discussed. Power electronic applications...

  15. Development of Electron Magnetic Spectrometer and Application

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The interaction between ultra-short pulse laser and solid plasma produces hot electron. Thereare many methods to study hot electron spectrum and space distribution. But the way of electron magnetic spectrometer is the most directional method. Particles with charge act circle movement in spare magnetic field. Different energy electrons have different whirl radius. So along whirl diameter direction electron spectrum can be obtained. Actually, electron is affected by gravity excursion and magnetic grads and curvature excursion besides lawrence power. The direction of

  16. A simple method for conversion of airborne gamma-ray spectra to ground level doses

    DEFF Research Database (Denmark)

    Korsbech, Uffe C C; Bargholz, Kim

    1996-01-01

    A new and simple method for conversion of airborne NaI(Tl) gamma-ray spectra to dose rates at ground level has been developed. By weighting the channel count rates with the channel numbers a spectrum dose index (SDI) is calculated for each spectrum. Ground level dose rates then are determined...

  17. Ocean energy conversion - A reality

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.

    This chapter presents an overview of ocean energy conversion in respect of its significance as the renewable energy resources. It deals with the thermodynamic principles relating to ocean thermal energy conversion (OTEC). Besides, it provides an in...

  18. Achieving Fair Spectrum Allocation and Reduced Spectrum Handoff in Wireless Sensor Networks: Modeling via Biobjective Optimization

    Directory of Open Access Journals (Sweden)

    Sang-Seon Byun

    2014-01-01

    Full Text Available This paper considers the problem of centralized spectrum allocations in wireless sensor networks towards the following goals: (1 maximizing fairness, (2 reflecting the priority among sensor data, and (3 avoiding unnecessary spectrum handoff. We cast this problem into a multiobjective mixed integer nonconvex nonlinear programming that is definitely difficult to solve at least globally without any aid of conversion or approximation. To tackle this intractability, we first convexify the original problem using arithmetic-geometric mean approximation and logarithmic change of the decision variables and then deploy weighted Chebyshev norm-based scalarization method in order to collapse the multiobjective problem into a single objective one. Finally, we apply simple rounding method in order to obtain approximate integer solutions. The results obtained from the numerical experiments show that, by adjusting the weight on each objective function, the proposed algorithm allocates spectrum bands fairly with well observing each sensor’s priority and reduced spectrum handoffs.

  19. Infrared up-conversion microscope

    DEFF Research Database (Denmark)

    2014-01-01

    There is presented an up-conversion infrared microscope (110) arranged for imaging an associated object (130), wherein the up-conversion infrared microscope (110) comprises a non-linear crystal (120) arranged for up-conversion of infrared electromagnetic radiation, and wherein an objective optical...

  20. Infrared up-conversion telescope

    DEFF Research Database (Denmark)

    2014-01-01

    There is presented to an up-conversion infrared telescope (110) arranged for imaging an associated scene (130), wherein the up-conversion infrared telescope (110) comprises a non-linear crystal (120) arranged for up-conversion of infrared electromagnetic radiation, and wherein a first optical...