WorldWideScience

Sample records for resonance absorption takes

  1. Comment on resonant absorption

    International Nuclear Information System (INIS)

    Hammerling, P.

    1977-01-01

    An average over angles of incidence of the usual resonant absorption function is presented. This form is appropriate under experimental conditions where the angles of incidence vary greatly and in an unknown manner. For comparison a lens-ellipsoidal mirror illumination system with a known longitudinal aberration is considered. In the latter example the angles of incidence are readily obtained and the resulting resonance absorption function evaluated. The associated fields are calculated in a similar fashion. (author)

  2. Neutron resonance absorption theory

    International Nuclear Information System (INIS)

    Reuss, P.

    1991-11-01

    After some recalls on the physics of neutron resonance absorption during their slowing down, this paper presents the main features of the theoretical developments performed by the french school of reactor physics: the effective reaction rate method so called Livolant-Jeanpierre theory, the generalizations carried out by the author, and the probability table method [fr

  3. Slowing down with resonance absorption

    International Nuclear Information System (INIS)

    Moura Neto, C. de; Nair, R.P.K.

    1979-08-01

    The presence of heavy nuclei in nuclear reactors, in significant concentrations, facilitates the appearance of absorption resonances. For the moderation in the presence of absorbers an exact solution of the integral equations is possible by numerical methods. Approximated solutions for separated resonances in function of the practical width, (NR and NRIM approximations) are discussed in this paper. The method is generalized, presenting the solution by an intermediate approximation, in the definition of the resonance integral. (Author) [pt

  4. Far-wing light absorption induced by resonant or near-resonant collisions

    International Nuclear Information System (INIS)

    Cavalieri, S.; Celli, M.

    1996-01-01

    The authors have studied the absorption of light induced by a resonant or near-resonant collision between two atoms. The calculations have been performed by taking into account also the magnetic sublevels, which makes their theoretical predictions more applicable to realistic cases. Analytical expressions for the far-wing absorption cross-section have been obtained

  5. Uncertainty quantification in resonance absorption

    International Nuclear Information System (INIS)

    Williams, M.M.R.

    2012-01-01

    We assess the uncertainty in the resonance escape probability due to uncertainty in the neutron and radiation line widths for the first 21 resonances in 232 Th as given by . Simulation, quadrature and polynomial chaos methods are used and the resonance data are assumed to obey a beta distribution. We find the uncertainty in the total resonance escape probability to be the equivalent, in reactivity, of 75–130 pcm. Also shown are pdfs of the resonance escape probability for each resonance and the variation of the uncertainty with temperature. The viability of the polynomial chaos expansion method is clearly demonstrated.

  6. The resonance absorption controlled reactor

    International Nuclear Information System (INIS)

    Caro, R.

    1977-01-01

    In this report a new method of reactor control based on tho isotopic moderator composition variation is studied, taking as a reference a D 2 O/H 2 O system. With this method an spectacular increment in the burn-up degree and a sensible reduction of the conventional control system is obtained. An important part of this work has been the detailed analysis of the parameters affecting the neutron spectrum in a heterogeneous reactor. (Author) 50 refs

  7. The resonance absorption controlled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Caro, R

    1977-07-01

    In this report a new method of reactor control based on tho isotopic moderator composition variation is studied, taking as a reference a D{sub 2}O/H{sub 2}O system. With this method an spectacular increment in the burn-up degree and a sensible reduction of the conventional control system is obtained. An important part of this work has been the detailed analysis of the parameters affecting the neutron spectrum in a heterogeneous reactor. (Author) 50 refs.

  8. Relativistic effects in resonance absorption

    International Nuclear Information System (INIS)

    Drake, J.F.; Lee, Y.C.

    1976-01-01

    The role of the relativistic-electron-mass variation in the generation of plasma waves by the linear mode conversion of intense electromagnetic waves is investigated. The increase in the electron mass in high intensity regions of the mode-converted wave reduces the local plasma frequency and thereby strongly modifies the plasma-driver resonance. A spatial discontinuity in the structure of the mode-converted wave results and causes the wave to break. Under rather modest restrictions, the wave breaking resulting from these effects occurs before the wave amplitude is limited either by thermal convection or by breaking caused by previously investigated nonrelativistic effects. Consequently, the amplitude of the mode-converted plasma wave should saturate at a much lower level than previously predicted. For simplicity, the analysis is limited to the initial stages of mode conversion where the ion dynamics can be neglected. The validity of this approximation is discussed

  9. Buffer-gas-induced absorption resonances in Rb vapor

    International Nuclear Information System (INIS)

    Mikhailov, Eugeniy E.; Novikova, Irina; Rostovtsev, Yuri V.; Welch, George R.

    2004-01-01

    We observe transformation of the electromagnetically induced transparency (EIT) resonance into an absorption resonance in a Λ interaction configuration in a cell filled with 87 Rb and a buffer gas. This transformation occurs as one-photon detuning of the coupling fields is varied from the atomic transition. No such absorption resonance is found in the absence of a buffer gas. The width of the absorption resonance is several times smaller than the width of the EIT resonance, and the changes of absorption near these resonances are about the same. Similar absorption resonances are detected in the Hanle configuration in a buffered cell

  10. Contribution to analytical theory of neutron resonance absorption in heterogeneous reactor systems with cylindrical geometry

    International Nuclear Information System (INIS)

    Slipicevic, K.

    1968-12-01

    Following a review of the existing theories od resonance absorption this thesis includes a new approach for calculating the effective resonance integral of absorbed neutrons, new approximate formula for the penetration factor, an analysis of the effective resonance integral and the correction of the resonance integral taking into account the interference of potential and resonance dissipation. A separate chapter is devoted to calculation of the effective resonance integral for the regular reactor lattice with cylindrical fuel elements

  11. Heavy nucleus resonance absorption in heterogeneous lattices

    International Nuclear Information System (INIS)

    Coste, M.; Tellier, H.; Brienne-Raepsaet, C.; Van Der Gucht, C.

    1992-01-01

    To compute easily the neutron reaction rates in the resonance energy range, the reactor physicists use the self-shielding formalism and the effective cross-section concept. Usually, for these calculations, and equivalence process is used, in such a way that the absorption rate is correctly computed for the whole fuel pin. This procedure does not allow to preserve the spatial absorption rate distribution inside the pin. It is an important handicap if we want to reproduce the plutonium distribution in a spent fuel. To avoid this inconvenience, new improvements of the self-shielding formalism have been recently introduced in the new assembly calculation code of the French Atomic Energy Commission, APOLLO 2. With this improved formalism, it is now possible to represent the spatial and energetic dependence of the heavy nucleus absorption inside the fuel pin and to use a fine energy dependent equivalence process. As it does not exist clean experimental results for the spatial and energetic dependence of the absorption, the authors used reference calculations to qualify the self-shielding formalism. For the strongly self-shielded nuclei of interest in reactor physics, U238, Pu240 and Th232, the agreement between the self-shielding calculation and the reference ones is fairly good for the spatial and energetic dependence of the absorption rate

  12. Heavy nucleus resonant absorption calculation benchmarks

    International Nuclear Information System (INIS)

    Tellier, H.; Coste, H.; Raepsaet, C.; Van der Gucht, C.

    1993-01-01

    The calculation of the space and energy dependence of the heavy nucleus resonant absorption in a heterogeneous lattice is one of the hardest tasks in reactor physics. Because of the computer time and memory needed, it is impossible to represent finely the cross-section behavior in the resonance energy range for everyday computations. Consequently, reactor physicists use a simplified formalism, the self-shielding formalism. As no clean and detailed experimental results are available to validate the self-shielding calculations, Monte Carlo computations are used as a reference. These results, which were obtained with the TRIPOLI continuous-energy Monte Carlo code, constitute a set of numerical benchmarks than can be used to evaluate the accuracy of the techniques or formalisms that are included in any reactor physics codes. Examples of such evaluations, for the new assembly code APOLLO2 and the slowing-down code SECOL, are given for cases of 238 U and 232 Th fuel elements

  13. Heated electron distributions from resonant absorption

    International Nuclear Information System (INIS)

    DeGroot, J.S.; Tull, J.E.

    1975-01-01

    A simplified model of resonant absorption of obliquely incident laser light has been developed. Using a 1.5 dimensional electrostatic simulation computer code, it is shown that the inclusion of ion motion is critically important in determining the heated electron distributions from resonant absorption. The electromagnetic wave drives up an electron plasma wave. For long density scale lengths (Lapprox. =10 3 lambda/subD//sube/), the phase velocity of this wave is very large (ω/kapproximately-greater-than10V/sub th/) so that if heating does occur, a suprathermal tail of very energetic electrons is produced. However, the pressure due to this wave steepens the density profile until the density gradient scale length near the critical density (where the local plasma frequency equals the laser frequency) is of order 20lambda/subD//sube/. The electrostatic wave is thus forced to have a much lower phase velocity (ω/kapprox. =2.5V/sub th/). In this case, more electrons are heated to much lower velocities. The heated electron distributions are exponential in velocity space. Using a simple theory it is shown that this property of profile steepening applies to most of a typical laser fusion pulse. This steepening raises the threshold for parametric instabilities near the critical surface. Thus, the extensive suprathermal electron distributions typically produced by these parametric instabilities can be drastically reduced

  14. Resonant power absorption in helicon plasma sources

    International Nuclear Information System (INIS)

    Chen Guangye; Arefiev, Alexey V.; Bengtson, Roger D.; Breizman, Boris N.; Lee, Charles A.; Raja, Laxminarayan L.

    2006-01-01

    Helicon discharges produce plasmas with a density gradient across the confining magnetic field. Such plasmas can create a radial potential well for nonaxisymmetric whistlers, allowing radially localized helicon (RLH) waves. This work presents new evidence that RLH waves play a significant role in helicon plasma sources. An experimentally measured plasma density profile in an argon helicon discharge is used to calculate the rf field structure. The calculations are performed using a two-dimensional field solver under the assumption that the density profile is axisymmetric. It is found that RLH waves with an azimuthal wave number m=1 form a standing wave structure in the axial direction and that the frequency of the RLH eigenmode is close to the driving frequency of the rf antenna. The calculated resonant power absorption, associated with the RLH eigenmode, accounts for most of the rf power deposited into the plasma in the experiment

  15. Heavy nucleus resonant absorption in heterogeneous lattices

    International Nuclear Information System (INIS)

    Tellier, H.; Coste, M.; Raepsaet, C.; Van der Gucht, C.

    1992-11-01

    The new self shielding formalism which is implemented in the transport code APPOLO 2 allows to compute the space and the energy dependence of the resonant absorption rate inside a fuel rod. As it does not exist any experimental result to check such a computation, we used very sophisticated reference calculations to check the self shielding formalism. Two kinds of reference calculation were used: a multi-group slowing down calculation with a very detailed energy mesh and a MONTE CARLO computation with point wise cross sections. The purpose of this study is a comparison of the self-shielding result with the ones of the two reference calculations. The geometry of the fuel element is the one of a light water-reactor and the resonant nuclei are the most important self-shielded nuclei: 238U, 232Th or 240Pu. The reactor agreement between the three kinds of calculations is very satisfactory for the nominal water density and for a reduced water density which simulates incidental operating conditions

  16. Reflection effect of localized absorptive potential on non-resonant and resonant tunneling

    International Nuclear Information System (INIS)

    Rubio, A.; Kumar, N.

    1992-06-01

    The reflection due to absorptive potential (-iV i ) for resonant and non-resonant tunneling has been considered. We show that the effect of reflection leads to a non-monotonic dependence of absorption on the strength V i with a maximum absorption of typically 0.5. This has implications for the operation of resonant tunneling devices. General conceptual aspects of absorptive potentials are discussed. (author). 9 refs, 2 figs

  17. Absorption of continuum radiation in a resonant expanding gaseous sphere

    International Nuclear Information System (INIS)

    Shaparev, N Y

    2014-01-01

    The paper deals with absorption of external continuum radiation in a self-similarly expanding gaseous sphere. Frequency probability and integral probability of radiation absorption in the resonance frequency range are determined depending on the expansion velocity gradient and thickness of the optical medium. It is shown that expansion results in a reduced optical thickness of the medium and enhanced integral absorption. (paper)

  18. Resonant ULF absorption in storm time conditions

    Directory of Open Access Journals (Sweden)

    Badin V.I.

    2017-03-01

    Full Text Available The work deals with ULF radar observations of the high-latitude ionosphere. Doppler data from the Norwegian STARE instrument are analyzed for the moderate magnetic storm observed on December 31, 1999 – January 01, 2000. Upon averaging the Doppler signals along radar beams, the spectral power of signals is determined for each beam as a function of frequency ranging from 1 to 10 mHz. Sharp drops (about 10 dB of spectral powers with frequency are found for all radar beams. A variational analysis of spectral powers is carried out by least squares, with power drops being modeled by stepwise profiles constructed of mean spectral powers preceding and succeeding the drops. Using this variational analysis, the frequency of the power drop is determined for each radar beam. Being averaged over all beams, this frequency is 4.8±0.5 mHz. The results obtained are interpreted as resonant absorption of ultra-low-frequency (ULF waves occurring on eigenfrequencies of magnetic field lines over wave propagation from the magnetopause deep into the magnetosphere.

  19. Coherent enhancement of resonance-mediated multiphoton absorption

    International Nuclear Information System (INIS)

    Zhang, Shian; Zhang, Hui; Jia, Tianqing; Wang, Zugeng; Sun, Zhenrong

    2010-01-01

    In this paper, we theoretically investigate the coherent enhancement of resonance-mediated (2+2) four-photon absorption. It is found that by shaping the spectral phase with a π phase step, the resonance-mediated (2+2) four-photon transition probability can be enhanced. Furthermore, the coherent enhancement dependences on the detuning between the two two-photon absorptions, laser spectral bandwidth and laser centre frequency are explicitly discussed and analysed. We believe these theoretical results may play an important role in enhancing more complex resonance-mediated multiphoton absorption processes.

  20. Interference scattering effects on intermediate resonance absorption at operating temperatures

    International Nuclear Information System (INIS)

    Goldstein, R.

    1975-01-01

    Resonance integrals may be accurately calculated using the intermediate resonance (IR) approximation. Results are summarized for the case of an absorber with given potential scattering cross sections and interference scattering parameter admixed with a non absorbing moderator of given cross section and located in a narrow resonance moderating medium. From the form of the IR solutions, it is possible to make some general observations about effects of interference scattering on resonance absorption. 2 figures

  1. Nonresonant absorption of one photon by one atom and resonant absorption of two photons by two atoms

    International Nuclear Information System (INIS)

    Mizushima, Masataka

    1990-01-01

    When a radiation field of frequency ω 1 interacts with atoms, etch of which has a transition frequency ω ba =(E b -E a )/h, with ω 1 -ω ba =Δ≠0, nonresonant absorption can take place with probability P 1 inversely proportional to Δ 2 (a pressure broadening). When another radiation field of frequency ω 2 , such that ω 1 +ω 2 =2ω ba, interacts simultaneously with the gas a resonant two-photon absorption can take place in addition to the nonresonant absorption. The probability of this two-photon absorption process, P 2 , is found to be inversely proportional to Δ 4 . If Ω=| | is the Rabi frequency of the transition, it is found that P 2 /(P 1 (Δ)+P 1 (-Δ)) is given by 12 {Ω(-Δ)Ω(-Δ)} 2 / {Δ 2 (Ω(-Δ) 2 + Ω(Δ) 2 )}. (author)

  2. Quasi-Resonant Absorption for Quantum Efficiency Improvement in Detectors

    Data.gov (United States)

    National Aeronautics and Space Administration — Quasi-resonant absorption has been demonstrated to enhance the quantum efficiency of devices across the spectrum, but specifically it is a challenge in the UV...

  3. Polarization control of intermediate state absorption in resonance-mediated multi-photon absorption process

    International Nuclear Information System (INIS)

    Xu, Shuwu; Yao, Yunhua; Jia, Tianqing; Ding, Jingxin; Zhang, Shian; Sun, Zhenrong; Huang, Yunxia

    2015-01-01

    We theoretically and experimentally demonstrate the control of the intermediate state absorption in an (n + m) resonance-mediated multi-photon absorption process by the polarization-modulated femtosecond laser pulse. An analytical solution of the intermediate state absorption in a resonance-mediated multi-photon absorption process is obtained based on the time-dependent perturbation theory. Our theoretical results show that the control efficiency of the intermediate state absorption by the polarization modulation is independent of the laser intensity when the transition from the intermediate state to the final state is coupled by the single-photon absorption, but will be affected by the laser intensity when this transition is coupled by the non-resonant multi-photon absorption. These theoretical results are experimentally confirmed via a two-photon fluorescence control in (2 + 1) resonance-mediated three-photon absorption of Coumarin 480 dye and a single-photon fluorescence control in (1 + 2) resonance-mediated three-photon absorption of IR 125 dye. (paper)

  4. Broadband absorption through extended resonance modes in random metamaterials

    International Nuclear Information System (INIS)

    Hao, J.; Niemiec, R.; Lheurette, É.; Lippens, D.; Burgnies, L.

    2016-01-01

    The properties of disordered metamaterial absorbers are analyzed on the basis of numerical simulations and experimental characterizations. A broadening of the absorption spectrum is clearly evidenced. This effect is the consequence of both the coupling between nearby resonators leading to the occurrence of extended magnetic resonance modes and the interconnection of elementary particles yielding the definition of resonating clusters. The angular robustness of the absorbing structure under oblique incidence is also demonstrated for a wide domain of angles.

  5. An analysis of uncertainties in the reference resonance absorption calculations

    International Nuclear Information System (INIS)

    Milosevic, M.; Pesic, M.

    1997-05-01

    A recently appeared generation of design-oriented methods, which allows to compute the space and energy dependence of the resonant absorption inside the fuel rod, induces a new problem of validation of results obtained with improved resonance treatments, Because no experimental results are available on the spatial and energy distribution of resonance absorption, detailed reference calculations were generated with the continuos-energy Monte Carlo and energy pointwise slowing-down codes. The accuracy of these calculations depends>on various in.fluences. In this paper an analysis of some influences, such as differences ;n nuclear data libraries and philosophy of reproducing the cross section data, is presented. Example application is given for a calculation benchmark that consists of determination of resonance absorption by 238 U in typical PWR pin cell geometry (author)

  6. Subwavelength single layer absorption resonance antireflection coatings

    NARCIS (Netherlands)

    Huber, S. P.; van de Kruijs, R. W. E.; Yakshin, A. E.; Zoethout, E.; Boller, K.-J.; F. Bijkerk,

    2014-01-01

    We present theoretically derived design rules for an absorbing resonance antireflection coating for the spectral range of 100 &\\#x02013; 400 nm, applied here on top of a molybdenum-silicon multilayer mirror (Mo/Si MLM) as commonly used in extreme ultraviolet lithography. The design rules for

  7. Subwavelength single layer absorption resonance antireflection coatings

    NARCIS (Netherlands)

    Huber, Sebastiaan; van de Kruijs, Robbert Wilhelmus Elisabeth; Yakshin, Andrey; Zoethout, E.; Boller, Klaus J.; Bijkerk, Frederik

    2014-01-01

    We present theoretically derived design rules for an absorbing resonance antireflection coating for the spectral range of 100−400 nm, applied here on top of a molybdenum-silicon multilayer mirror (Mo/Si MLM) as commonly used in extreme ultraviolet lithography. The design rules for optimal

  8. Absorption of acoustic waves by sunspots. II - Resonance absorption in axisymmetric fibril models

    Science.gov (United States)

    Rosenthal, C. S.

    1992-01-01

    Analytical calculations of acoustic waves scattered by sunspots which concentrate on the absorption at the magnetohydrodynamic Alfven resonance are extended to the case of a flux-tube embedded in a uniform atmosphere. The model is based on a flux-tubes of varying radius that are highly structured, translationally invariant, and axisymmetric. The absorbed fractional energy is determined for different flux-densities and subphotospheric locations with attention given to the effects of twist. When the flux is highly concentrated into annuli efficient absorption is possible even when the mean magnetic flux density is low. The model demonstrates low absorption at low azimuthal orders even in the presence of twist which generally increases the range of wave numbers over which efficient absorption can occur. Resonance absorption is concluded to be an efficient mechanism in monolithic sunspots, fibril sunspots, and plage fields.

  9. Successive collision calculation of resonance absorption (AWBA Development Program)

    International Nuclear Information System (INIS)

    Schmidt, E.; Eisenhart, L.D.

    1980-07-01

    The successive collision method for calculating resonance absorption solves numerically the neutron slowing down problem in reactor lattices. A discrete energy mesh is used with cross sections taken from a Monte Carlo library. The major physical approximations used are isotropic scattering in both the laboratory and center-of-mass systems. This procedure is intended for day-to-day analysis calculations and has been incorporated into the current version of MUFT. The calculational model used for the analysis of the nuclear performance of LWBR includes this resonance absorption procedure. Test comparisons of results with RCPO1 give very good agreement

  10. Absorption of resonant electromagnetic radiation in electron-atom collisions

    International Nuclear Information System (INIS)

    Arslanbekov, T.U.; Pazdzerskii, V.A.; Usachenko, V.I.

    1986-01-01

    Nonrelativistic quantum theory is used to study the possibility of amplification of electromagnetic radiation in forced braking scattering of an electron beam on atoms. The interaction of the atom with the electromagnetic field is considered in the resonant approximation. Cases of large and small detuning from resonance are considered. It is shown that for any orientation of the electron beam relative to the field polarization vector, absorption of radiation occurs, with the major contribution being produced by atomic electrons

  11. Resonance absorption of ICRF wave in edge plasma

    International Nuclear Information System (INIS)

    Sugihara, Ryo; Yamanaka, Kaoru.

    1987-07-01

    An edge plasma is shown to significantly absorb ICRF wave when a resonant triplet, a cutoff-resonance-cutoff triplet, is constructed in the evanescent region. Two-ion-component plasmas in a torus are considered though the plasmas are modeled by a slab in which the density changes linearly along the x-axis. The resonance is a perpendicular-ion-cyclotron resonance, i.e., an Alfven resonance, and is formed when the applied frequency ω is smaller than the local cyclotron frequency, at the edge of the antenna side, of the lighter species of ions. Roughly the absorption rate A b is given by M 2 for M 2 >> S 2 and S 4 for S 2 >> M 2 where M = k y l and S ≅ k z l and l is a scale length of the order of the plasma minor radius and k y and k z are the perpendicular and the parallel components of the wave vector. It is noted that the both quantities, M and S, readily become of the order of unity. Since A b is not very sensitive to the density ratio of the two ion species, a few percent of impurities may cause a significant absorption. As the mass ratio of the two ion species comes close to unity the triplet forms readily. Therefore a D-T plasma seems to suffer more easily this kind of resonance absorption than a D-H plasma. (author)

  12. Absorption enhancement in graphene with an efficient resonator

    DEFF Research Database (Denmark)

    Xiao, Binggang; Gu, Mingyue; Qin, Kang

    2017-01-01

    Graphene can be utilized in designing tunable terahertz (THz) devices due to its tunability of sheet conductivity, suffering however with weak light-graphene interactions. In this paper, an absorption enhancement in graphene using a Fabry–Perot resonator is presented, and its performance has been...

  13. Resonant Self-Trapping and Absorption of Intense Bessel Beams

    International Nuclear Information System (INIS)

    Fan, J.; Parra, E.; Milchberg, H. M.

    2000-01-01

    We report the observation of resonant self-trapping and enhanced laser-plasma heating resulting from propagation of high intensity Bessel beams in neutral gas. The enhancement in absorption and plasma heating is directly correlated to the spatial trapping of laser radiation. (c) 2000 The American Physical Society

  14. Non-resonant microwave absorption studies of superconducting ...

    Indian Academy of Sciences (India)

    Abstract. Non-resonant microwave absorption (NRMA) studies of superconducting MgB2 and a sample containing 10% by weight of MgO in MgB2 are reported. The NRMA results indicate near absence of intergranular weak links in the pure MgB2 sample. A linear temperature dependence of the lower critical field Hc1 is ...

  15. Resonant absorption of electromagnetic waves in transition anisotropic media.

    Science.gov (United States)

    Kim, Kihong

    2017-11-27

    We study the mode conversion and resonant absorption phenomena occurring in a slab of a stratified anisotropic medium, optical axes of which are tilted with respect to the direction of inhomogeneity, using the invariant imbedding theory of wave propagation. When the tilt angle is zero, mode conversion occurs if the longitudinal component of the permittivity tensor, which is the one in the direction of inhomogeneity in the non-tilted case, varies from positive to negative values within the medium, while the transverse component plays no role. When the tilt angle is nonzero, the wave transmission and absorption show an asymmetry under the sign change of the incident angle in a range of the tilt angle, while the reflection is always symmetric. We calculate the reflectance, the transmittance and the absorptance for several configurations of the permittivity tensor and find that resonant absorption is greatly enhanced when the medium from the incident surface to the resonance region is hyperbolic than when it is elliptic. For certain configurations, the transmittance and absorptance curves display sharp peaks at some incident angles determined by the tilt angle.

  16. The Resonance Absorption of Uranium Metal and Oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hellstrand, E; Lundgren, G

    1962-06-15

    The resonance integrals for uranium metal and uranium oxide have been determined for a 1/E flux. The following results were obtained Metal RI 2.95 + 25.8{radical}(S/M); Oxide RI = 4.15 + 26.6{radical}(S/M). The oxide value agrees with the expression found earlier at this laboratory. But the result for the metal is 4. 5 % larger than the earlier one. In addition, the resonance absorption in a R1 fuel rod has been compared with that for a cadmium-covered rod placed in an approximate cell boundary flux. The former came out 3 % larger than the latter. A comparison of the fuel rod absorption with that for a 1/E flux yields a corresponding figure of 7 %. The neutron flux was monitored below the lowest resonance in uranium.

  17. Stochasticity of the energy absorption in the electron cyclotron resonance

    International Nuclear Information System (INIS)

    Gutierrez T, C.; Hernandez A, O.

    1998-01-01

    The energy absorption mechanism in cyclotron resonance of the electrons is a present problem, since it could be considered from the stochastic point of view or this related with a non-homogeneous but periodical of plasma spatial structure. In this work using the Bogoliubov average method for a multi periodical system in presence of resonances, the drift equations were obtained in presence of a RF field for the case of electron cyclotron resonance until first order terms with respect to inverse of its cyclotron frequency. The absorbed energy equation is obtained on part of electrons in a simple model and by drift method. It is showed the stochastic character of the energy absorption. (Author)

  18. Contribution to analytical theory of neutron resonance absorption in heterogeneous reactor systems with cylindrical geometry; Prilog analitickoj teoriji rezonzntne apsorpcije neutron u heterogenom reaktorskim sistemima sa cilindricnom geometrijom

    Energy Technology Data Exchange (ETDEWEB)

    Slipicevic, K [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1968-07-01

    Following a review of the existing theories od resonance absorption this thesis includes a new approach for calculating the effective resonance integral of absorbed neutrons, new approximate formula for the penetration factor, an analysis of the effective resonance integral and the correction of the resonance integral taking into account the interference of potential and resonance dissipation. A separate chapter is devoted to calculation of the effective resonance integral for the regular reactor lattice with cylindrical fuel elements.

  19. Resonant photoionization absorption spectra of spherical quantum dots

    CERN Document Server

    Bondarenko, V

    2003-01-01

    We study theoretically the mid-infrared photon absorption spectra due to bound-free transitions of electrons in individual spherical quantum dots. It is established that change of the dot size in one or two atomic layers or/and number of electrons by one or two can change the peak value of the absorption spectra in orders of magnitude and energy of absorbed photons by tens of millielectronvolts. The reason for this is the formation of specific free states, called resonance states. Numerical calculations are performed for quantum dots (QDs) with radius varying up to 200 A, and one to eight electrons occupying the two lowest bound states. It is supposed that realistic QD systems with resonance states would be of much advantage to design novel infrared QD photo-detectors.

  20. Behavioral and Biological Effects of Resonant Electromagnetic Absorption in Rats.

    Science.gov (United States)

    1976-11-01

    for 23-550 MHz, biological phantom materials to simulate tissue properties, monopole -above-ground radiation chamber, design of a waveguide slot array...Resonant Electromagnetic Power Absorption in Rats" L T OF FTCTIF S A,’L i .LIS SFigure Pa 1 A photograiph of the monopole -above-gruund radiation...and mice without ground effects (L/2b = 3.25 where 21Tb is the "average" circumference of the animals) ........ .................... ... 20 8

  1. Towards higher stability of resonant absorption measurements in pulsed plasmas.

    Science.gov (United States)

    Britun, Nikolay; Michiels, Matthieu; Snyders, Rony

    2015-12-01

    Possible ways to increase the reliability of time-resolved particle density measurements in pulsed gaseous discharges using resonant absorption spectroscopy are proposed. A special synchronization, called "dynamic source triggering," between a gated detector and two pulsed discharges, one representing the discharge of interest and another being used as a reference source, is developed. An internal digital delay generator in the intensified charge coupled device camera, used at the same time as a detector, is utilized for this purpose. According to the proposed scheme, the light pulses from the reference source follow the gates of detector, passing through the discharge of interest only when necessary. This allows for the utilization of short-pulse plasmas as reference sources, which is critical for time-resolved absorption analysis of strongly emitting pulsed discharges. In addition to dynamic source triggering, the reliability of absorption measurements can be further increased using simultaneous detection of spectra relevant for absorption method, which is also demonstrated in this work. The proposed methods are illustrated by the time-resolved measurements of the metal atom density in a high-power impulse magnetron sputtering (HiPIMS) discharge, using either a hollow cathode lamp or another HiPIMS discharge as a pulsed reference source.

  2. Towards higher stability of resonant absorption measurements in pulsed plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Britun, Nikolay, E-mail: nikolay.britun@umons.ac.be [Chimie des Interactions Plasma Surface (ChIPS), CIRMAP, Université de Mons, 23 Place du Parc, B-7000 Mons (Belgium); Michiels, Matthieu [Materia Nova Research Center, Parc Initialis, B-7000 Mons (Belgium); Snyders, Rony [Chimie des Interactions Plasma Surface (ChIPS), CIRMAP, Université de Mons, 23 Place du Parc, B-7000 Mons (Belgium); Materia Nova Research Center, Parc Initialis, B-7000 Mons (Belgium)

    2015-12-15

    Possible ways to increase the reliability of time-resolved particle density measurements in pulsed gaseous discharges using resonant absorption spectroscopy are proposed. A special synchronization, called “dynamic source triggering,” between a gated detector and two pulsed discharges, one representing the discharge of interest and another being used as a reference source, is developed. An internal digital delay generator in the intensified charge coupled device camera, used at the same time as a detector, is utilized for this purpose. According to the proposed scheme, the light pulses from the reference source follow the gates of detector, passing through the discharge of interest only when necessary. This allows for the utilization of short-pulse plasmas as reference sources, which is critical for time-resolved absorption analysis of strongly emitting pulsed discharges. In addition to dynamic source triggering, the reliability of absorption measurements can be further increased using simultaneous detection of spectra relevant for absorption method, which is also demonstrated in this work. The proposed methods are illustrated by the time-resolved measurements of the metal atom density in a high-power impulse magnetron sputtering (HiPIMS) discharge, using either a hollow cathode lamp or another HiPIMS discharge as a pulsed reference source.

  3. ROLAIDS-CPM: A code for accurate resonance absorption calculations

    International Nuclear Information System (INIS)

    Kruijf, W.J.M. de.

    1993-08-01

    ROLAIDS is used to calculate group-averaged cross sections for specific zones in a one-dimensional geometry. This report describes ROLAIDS-CPM which is an extended version of ROLAIDS. The main extension in ROLAIDS-CPM is the possibility to use the collision probability method for a slab- or cylinder-geometry instead of the less accurate interface-currents method. In this way accurate resonance absorption calculations can be performed with ROLAIDS-CPM. ROLAIDS-CPM has been developed at ECN. (orig.)

  4. Depolarisation effects in resonance absorption neutron polarising filters

    International Nuclear Information System (INIS)

    Mayers, J.

    1982-06-01

    The depolarisation of a neutron beam passing through a system of magnetically misaligned single domain particles is examined and simulated using a Monte-Carlo programme. The results of the simulations are in excellent agreement with those of analytic calculations within the regimes where such calculations are applicable. The simulations have been used in the estimation of the polarising efficiency and transmittance of a resonance absorption filter containing partially aligned particles of SmCo 5 . It is shown that the application of strong magnetic fields (approximately equal to 2T) should significantly improve the filter performance. A method of measuring this improvement is suggested. (author)

  5. Spatially resolved remote measurement of temperature by neutron resonance absorption

    Energy Technology Data Exchange (ETDEWEB)

    Tremsin, A.S., E-mail: ast@ssl.berkeley.edu [Space Sciences Laboratory, University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Kockelmann, W.; Pooley, D.E. [STFC, Rutherford Appleton Laboratory, ISIS Facility, Didcot OX11 0QX (United Kingdom); Feller, W.B. [NOVA Scientific, Inc., 10 Picker Road, Sturbridge, MA 01566 (United States)

    2015-12-11

    Deep penetration of neutrons into most engineering materials enables non-destructive studies of their bulk properties. The existence of sharp resonances in neutron absorption spectra enables isotopically-resolved imaging of elements present in a sample, as demonstrated by previous studies. At the same time the Doppler broadening of resonance peaks provides a method of remote measurement of temperature distributions within the same sample. This technique can be implemented at a pulsed neutron source with a short initial pulse allowing for the measurement of the energy of each registered neutron by the time of flight technique. A neutron counting detector with relatively high timing and spatial resolution is used to demonstrate the possibility to obtain temperature distributions across a 100 µm Ta foil with ~millimeter spatial resolution. Moreover, a neutron transmission measurement over a wide energy range can provide spatially resolved sample information such as temperature, elemental composition and microstructure properties simultaneously.

  6. Long Elastic Open Neck Acoustic Resonator for low frequency absorption

    Science.gov (United States)

    Simon, Frank

    2018-05-01

    Passive acoustic liners, used in aeronautic engine nacelles to reduce radiated fan noise, have a quarter-wavelength behavior, because of perforated sheets backed by honeycombs (with one or two degrees of freedom). However, their acoustic absorption ability is naturally limited to medium and high frequencies because of constraints in thickness. The low ratio "plate thickness/hole diameter" generates impedance levels dependent on the incident sound pressure level and the grazing mean flow (by a mechanism of nonlinear dissipation through vortex shedding), which penalises the optimal design of liners. The aim of this paper is to overcome this problem by a concept called LEONAR ("Long Elastic Open Neck Acoustic Resonator"), in which a perforated plate is coupled with tubes of variable lengths inserted in a limited volume of a back cavity. To do this, experimental and theoretical studies, using different types of liners (material nature, hole diameter, tube length, cavity thickness) are described in this paper. It is shown that the impedance can be precisely determined with an analytical approach based on parallel transfer matrices of tubes coupled to the cavity. Moreover, the introduction of tubes in a cavity of a conventional resonator generates a significant shift in the frequency range of absorption towards lower frequencies or allows a reduction of cavity thickness. The impedance is practically independent of sound pressure level because of a high ratio "tube length/tube hole diameter". Finally, a test led in an aeroacoustic bench suggests that a grazing flow at a bulk Mach number of 0.3 has little impact on the impedance value. These first results allow considering these resonators with linear behavior as an alternative to classical resonators, in particular, as needed for future Ultra High Bypass Ratio engines with shorter and thinner nacelles.

  7. Near resonant absorption by atoms in intense fluctuating laser fields

    International Nuclear Information System (INIS)

    Smith, S.J.

    1994-01-01

    The objective of this program was to make quantitative measurements of the effects of higher-order phase/frequency correlations in a laser beam on nonlinear optical absorption processes in atoms. The success of this program was due in large part to a unique experimental capability for modulating the extracavity beam of a stabilized (approx-lt 200 kHz) continuous-wave laser with statistically-well-characterized stochastic phase (or frequency) fluctuations, in order to synthesize laser bandwidths to ∼20 MHz (depending on noise amplitude), with profiles variable between Gaussian and Lorentzian (depending on noise bandwidth). Laser driven processes investigated included the following: (1) the optical Autler-Towns effect in the 3S 1/2 (F = 2, M F = 2) → 3P 3/2 (F = 3, M F = 3) two- level Na resonance, using a weak probe to the 4D 5/2 level; (2) the variance and spectra of fluorescence intensity fluctuations in the two-level Na resonance; (3) the Hanle effect in the 1 S 0 - 3 P 1 , transition at λ = 555.6 nm in 174 Yb; (4) absorption (and gain) of a weak probe, when the probe is a time-delayed replica of the resonant (with the two-level Na transition) pump laser; and (5) four-wave-mixing in a phase-conjugate geometry, in a sodium cell, and, finally, in a diffuse atomic sodium beam. The experimental results from these several studies have provided important confirmation of advanced theoretical methods

  8. RESONANT ABSORPTION OF AXISYMMETRIC MODES IN TWISTED MAGNETIC FLUX TUBES

    Energy Technology Data Exchange (ETDEWEB)

    Giagkiozis, I.; Verth, G. [Solar Plasma Physics Research Centre, School of Mathematics and Statistics, University of Sheffield, Hounsfield Road, Hicks Building, Sheffield, S3 7RH (United Kingdom); Goossens, M.; Doorsselaere, T. Van [Centre for mathematical Plasma Astrophysics, Mathematics Department, KU Leuven, Celestijnenlaan 200B bus 2400, B-3001 Leuven (Belgium); Fedun, V. [Department of Automatic Control and Systems Engineering, University of Sheffield, Mappin Street, Amy Johnson Building, Sheffield, S1 3JD (United Kingdom)

    2016-06-01

    It has been shown recently that magnetic twist and axisymmetric MHD modes are ubiquitous in the solar atmosphere, and therefore the study of resonant absorption for these modes has become a pressing issue because it can have important consequences for heating magnetic flux tubes in the solar atmosphere and the observed damping. In this investigation, for the first time, we calculate the damping rate for axisymmetric MHD waves in weakly twisted magnetic flux tubes. Our aim is to investigate the impact of resonant damping of these modes for solar atmospheric conditions. This analytical study is based on an idealized configuration of a straight magnetic flux tube with a weak magnetic twist inside as well as outside the tube. By implementing the conservation laws derived by Sakurai et al. and the analytic solutions for weakly twisted flux tubes obtained recently by Giagkiozis et al. we derive a dispersion relation for resonantly damped axisymmetric modes in the spectrum of the Alfvén continuum. We also obtain an insightful analytical expression for the damping rate in the long wavelength limit. Furthermore, it is shown that both the longitudinal magnetic field and the density, which are allowed to vary continuously in the inhomogeneous layer, have a significant impact on the damping time. Given the conditions in the solar atmosphere, resonantly damped axisymmetric modes are highly likely to be ubiquitous and play an important role in energy dissipation. We also suggest that, given the character of these waves, it is likely that they have already been observed in the guise of Alfvén waves.

  9. Resonant absorption of radar waves by a magnetized collisional plasma

    International Nuclear Information System (INIS)

    Sun Aiping; Tong Honghui; Shen Liru; Tang Deli; Qiu Xiaoming

    2001-01-01

    The propagation of radar waves in a magnetized collisional plasma slab is studied numerically. It is found for uniform plasma that: first, the wave attenuation and absorbed power show a peak value, i.e., resonant absorption when the collision frequency f en = 0.1, 0.5, 1 GHz and the wave frequency nears upper hybrid frequency. Secondly, the attenuation, absorbed, and transmitted power curves become flat at f en = 5, 10 Ghz. thirdly, the attenuation and absorbed power increase with plasma density, and the attenuation and the proportion of absorbed power can reach 100 dB and 80%, respectively, at the plasma density n = 10 11 cm -3 . For nonuniform plasma, the peak value of reflected power is larger than that in uniform plasma. So, uniform magnetized plasma is of more benefit to plasma cloaking

  10. The thermal neutron absorption cross-sections, resonance integrals and resonance parameters of silicon and its stable isotopes

    International Nuclear Information System (INIS)

    Story, J.S.

    1969-09-01

    The data available up to the end of November 1968 on the thermal neutron absorption cross-sections, resonance absorption integrals, and resonance parameters of silicon and its stable isotopes are collected and discussed. Estimates are given of the mean spacing of the energy levels of the compound nuclei near the neutron binding energy. It is concluded that the thermal neutron absorption cross-section and resonance absorption integral of natural silicon are not well established. The data on these two parameters are somewhat correlated, and three different assessments of the resonance integral are presented which differ over-all by a factor of 230. Many resonances have been detected by charged particle reactions which have not yet been observed in neutron cross-section measurements. One of these resonances of Si 2 8, at E n = 4 ± 5 keV might account for the large resonance integral which is derived, very uncertainly, from integral data. The principal source of the measured resonance integral of Si 3 0 has not yet been located. The thermal neutron absorption cross-section of Si 2 8 appears to result mainly from a negative energy resonance, possibly the resonance at E n = - 59 ± 5 keV detected by the Si 2 8 (d,p) reaction. (author)

  11. Terahertz sensing of highly absorptive water-methanol mixtures with multiple resonances in metamaterials.

    Science.gov (United States)

    Chen, Min; Singh, Leena; Xu, Ningning; Singh, Ranjan; Zhang, Weili; Xie, Lijuan

    2017-06-26

    Terahertz sensing of highly absorptive aqueous solutions remains challenging due to strong absorption of water in the terahertz regime. Here, we experimentally demonstrate a cost-effective metamaterial-based sensor integrated with terahertz time-domain spectroscopy for highly absorptive water-methanol mixture sensing. This metamaterial has simple asymmetric wire structures that support multiple resonances including a fundamental Fano resonance and higher order dipolar resonance in the terahertz regime. Both the resonance modes have strong intensity in the transmission spectra which we exploit for detection of the highly absorptive water-methanol mixtures. The experimentally characterized sensitivities of the Fano and dipole resonances for the water-methanol mixtures are found to be 160 and 305 GHz/RIU, respectively. This method provides a robust route for metamaterial-assisted terahertz sensing of highly absorptive chemical and biochemical materials with multiple resonances and high accuracy.

  12. A generalized resonating group method with absorptive interaction

    International Nuclear Information System (INIS)

    Hernandez, E.; Mondragon, A.; Instituto Nacional de Investigaciones Nucleares, Mexico City)

    1981-01-01

    A generalized Hill-Wheeler equation for the elastic collision at two composite nuclei is obtained projecting the complete many-body Schroedinger equation on the subspace of model internal wave functions and on its orthogonal complement. We get a new, non hermitian (absorptive) interaction term W which takes into account the flux loss in the elastic channel, besides the usual RGM effective Hamiltonian and normalization kernels. A perturbation series expansion for W containing only linked diagrams is given. Finally, the antisymmetrized product of internal wave functions of the fragments that appear in the projection operator is expressed in terms of complex generator coordinates, then the terms appearing in effective interaction can be written as matrix elements of the microscopic interactions and/or the antisymmetrizer between two center shell model states. (author)

  13. Procedure and code for calculating black control rods taking into account epithermal absorption, code CAS-1

    International Nuclear Information System (INIS)

    Martinc, R.; Trivunac, N.; Zivkovic, Z.

    1964-12-01

    This report describes the computer code CAS-1, calculation method and procedure applied for calculating the black control rods taking into account the epithermal neutron absorption. Results obtained for supercell method applied for regular lattice reflected in the multiplication medium is part of this report in addition to the computer code manual

  14. Sound absorption of a new oblique-section acoustic metamaterial with nested resonator

    Science.gov (United States)

    Gao, Nansha; Hou, Hong; Zhang, Yanni; Wu, Jiu Hui

    2018-02-01

    This study designs and investigates high-efficiency sound absorption of new oblique-section nested resonators. Impedance tube experiment results show that different combinations of oblique-section nest resonators have tunable low-frequency bandwidth characteristics. The sound absorption mechanism is due to air friction losses in the slotted region and the sample structure resonance. The acousto-electric analogy model demonstrates that the sound absorption peak and bandwidth can be modulated over an even wider frequency range by changing the geometric size and combinations of structures. The proposed structure can be easily fabricated and used in low-frequency sound absorption applications.

  15. Rapidly reconfigurable slow-light system based on off-resonant Raman absorption

    International Nuclear Information System (INIS)

    Vudyasetu, Praveen K.; Howell, John C.; Camacho, Ryan M.

    2010-01-01

    We present a slow-light system based on dual Raman absorption resonances in warm rubidium vapor. Each Raman absorption resonance is produced by a control beam in an off-resonant Λ system. This system combines all optical control of the Raman absorption and the low-dispersion broadening properties of the double Lorentzian absorption slow light. The bandwidth, group delay, and central frequency of the slow-light system can all be tuned dynamically by changing the properties of the control beam. We demonstrate multiple pulse delays with low distortion and show that such a system has fast switching dynamics and thus fast reconfiguration rates.

  16. Two-dimensional thermometry by using neutron resonance absorption spectrometer DOG

    International Nuclear Information System (INIS)

    Kamiyama, T.; Noda, H.; Kiyanagi, Y.; Ikeda, S.

    2001-01-01

    We applied the neutron resonance absorption spectroscopy to thermometry of a bulk object. The measurement was done by using the neutron resonance absorption spectrometer, DOG, installed at KENS, High Energy Accelerator Research Organization Neutron Source, which enables us to investigate effective temperature of a particular element by analyzing line width of resonance absorption spectrum. The effective temperature becomes consistence with the sample temperature above room temperature. For the analysis we applied the computed tomography method to reconstruct the temperature distribution on the object cross section. The results and the calculated distribution by the heat conducting equation are well agreed on the temperature difference inside the object. (author)

  17. Approaching Resonant Absorption of Environmental Xenobiotics Harmonic Oscillation by Linear Structures

    Directory of Open Access Journals (Sweden)

    Cornelia A. Bulucea

    2012-03-01

    Full Text Available Over the last several decades, it has become increasingly accepted that the term xenobiotic relates to environmental impact, since environmental xenobiotics are understood to be substances foreign to a biological system, which did not exist in nature before their synthesis by humans. In this context, xenobiotics are persistent pollutants such as dioxins and polychlorinated biphenyls, as well as plastics and pesticides. Dangerous and unstable situations can result from the presence of environmental xenobiotics since their harmful effects on humans and ecosystems are often unpredictable. For instance, the immune system is extremely vulnerable and sensitive to modulation by environmental xenobitics. Various experimental assays could be performed to ascertain the immunotoxic potential of environmental xenobiotics, taking into account genetic factors, the route of xenobiotic penetration, and the amount and duration of exposure, as well as the wave shape of the xenobiotic. In this paper, we propose an approach for the analysis of xenobiotic metabolism using mathematical models and corresponding methods. This study focuses on a pattern depicting mathematically modeled processes of resonant absorption of a xenobiotic harmonic oscillation by an organism modulated as an absorbing oscillator structure. We represent the xenobiotic concentration degree through a spatial concentration vector, and we model and simulate the oscillating regime of environmental xenobiotic absorption. It is anticipated that the results could be used to facilitate the assessment of the processes of environmental xenobiotic absorption, distribution, biotransformation and removal within the framework of compartmental analysis, by establishing appropriate mathematical models and simulations.

  18. A resonant absorption measurement in the reaction 26Mg(p, γ)27Al

    NARCIS (Netherlands)

    Leun, C. van der; Burhoven Jaspers, N.C.

    1966-01-01

    A resonant absorption measurement at the 1966 keV proton resonance in the reaction 26Mg(p, γ)27Al leads to an absolute determination of the resonance strength, (2J+1)ΓpΓγ/Γ, of 5.6±1.8 eV. Normalization of previously published strengths of 120 resonances in the reaction 26Mg(p, γ)27Al, reduces these

  19. Measurements of the effective total and resonance absorption cross sections for zircaloy-2 and zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Kocic, A; Markovic, V [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1967-04-15

    Zirconium and zircaloy-2 alloy, as constructive materials, have found wide application in reactor technology, especially in heavy water systems for two reasons: a) low neutron absorption cross section, b) good mechanical properties. The thickness of the zirconium and zircaloy-2 for different applications varies from several tenths of a millimeter to about ten millimeters. Therefore, to calculate reactor systems it is desirable to know the effective neutron absorption cross section for the range of thicknesses mention above. The thermal neutron cross sections for these materials are low and no appreciable variation of the effective neutron cross section occurs even for the largest thicknesses. However, this is not true for effective resonance absorption. On the other hand, due to the lack of detailed knowledge of the zirconium resonances, calculations of the effective resonance integrals cannot be performed. Therefore it is necessary to measure the effective total and resonance absorption cross section for zirconium (author)

  20. Experimental determination of resonance absorption cross sections for Zircaloy-2 and zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Kocic, A; Markovic, V [Boris Kidric Institute of Nuclear Sciences, Vinca, Beograd (Yugoslavia)

    1968-05-15

    The integral absorption cross section for the neutron spectrum and the thermal absorption cross section for zircaloy-2 have been determined using the pile oscillator technique. Using both values and a measured ratio of the epithermal to the thermal flux, the effective resonance integrals were obtained. After subtraction of the contributions for alloy and impurity elements, the effective resonance integrals for zirconium were evaluated. An extrapolated value of 0.91{+-}0.10 was obtained for the dilute integral. (author)

  1. Benchmark calculations on resonance absorption by 238U in a PWR pin-cell geometry

    International Nuclear Information System (INIS)

    Kruijf, W.J.M. de; Janssen, A.J.

    1993-12-01

    Very accurate Monte Carlo calculations with MCNP have been performed to serve as a reference for benchmark calculations on resonance absorption by 238 U in a typical PWR pin-cell geometry. Calculations with the energy-pointwise slowing down code ROLAIDS-CPM show that this code calculates the resonance absorption accurately. Calculations with the multigroup discrete ordinates code XSDRN show that accurate results can only be achieved with a very fine energy mesh. (orig.)

  2. Study of the influence of chemical binding on resonant absorption and scattering of neutrons; Etude de l'influence des liaisons chimiques sur l'absorption et la diffusion des neutrons aux energies de resonance

    Energy Technology Data Exchange (ETDEWEB)

    Naberejnev, D.G. [Aix-Marseille-1 Univ., 13 - Marseille (France)

    1999-02-01

    At present time the problem of taking into account of the crystalline binding in the heavy nuclei resonance range is not correctly treated in nuclear data processing codes. The present work deals separately with resonant absorption and scattering of neutrons. The influence of crystalline binding is considered for both types of reactions in the harmonic crystal frame work. The harmonic crystal model is applied to the study of resonant absorption cross sections to show the inconsistency of the free gas model widely in use in reactor neutronics. The errors due to the use of the latter were found to be non negligible. These errors should be corrected by introducing a more elaborated harmonic crystal model in codes for resonances analysis and on the nuclear data processing stage. Currently the influence of crystalline binding on transfer cross section in the resonance domain is taken into account in a naive manner using the model of the free nucleus at rest in the laboratory system. In this work I present a formalism (Uncoupled Phonon Approximation) which permits to consider in more detail the crystalline structure of the nuclear fuel. This formalism shows new features in comparison with the static model. (author)

  3. Study of the influence of chemical binding on resonant absorption and scattering of neutrons; Etude de l'influence des liaisons chimiques sur l'absorption et la diffusion des neutrons aux energies de resonance

    Energy Technology Data Exchange (ETDEWEB)

    Naberejnev, D G [Aix-Marseille-1 Univ., 13 - Marseille (France)

    1999-02-01

    At present time the problem of taking into account of the crystalline binding in the heavy nuclei resonance range is not correctly treated in nuclear data processing codes. The present work deals separately with resonant absorption and scattering of neutrons. The influence of crystalline binding is considered for both types of reactions in the harmonic crystal frame work. The harmonic crystal model is applied to the study of resonant absorption cross sections to show the inconsistency of the free gas model widely in use in reactor neutronics. The errors due to the use of the latter were found to be non negligible. These errors should be corrected by introducing a more elaborated harmonic crystal model in codes for resonances analysis and on the nuclear data processing stage. Currently the influence of crystalline binding on transfer cross section in the resonance domain is taken into account in a naive manner using the model of the free nucleus at rest in the laboratory system. In this work I present a formalism (Uncoupled Phonon Approximation) which permits to consider in more detail the crystalline structure of the nuclear fuel. This formalism shows new features in comparison with the static model. (author)

  4. Resonant behaviour of MHD waves on magnetic flux tubes. I - Connection formulae at the resonant surfaces. II - Absorption of sound waves by sunspots

    Science.gov (United States)

    Sakurai, Takashi; Goossens, Marcel; Hollweg, Joseph V.

    1991-01-01

    The present method of addressing the resonance problems that emerge in such MHD phenomena as the resonant absorption of waves at the Alfven resonance point avoids solving the fourth-order differential equation of dissipative MHD by recourse to connection formulae across the dissipation layer. In the second part of this investigation, the absorption of solar 5-min oscillations by sunspots is interpreted as the resonant absorption of sounds by a magnetic cylinder. The absorption coefficient is interpreted (1) analytically, under certain simplifying assumptions, and numerically, under more general conditions. The observed absorption coefficient magnitude is explained over suitable parameter ranges.

  5. Heat Dissipation of Resonant Absorption in Metal Nanoparticle-Polymer Films Described at Particle Separation Near Resonant Wavelength

    Directory of Open Access Journals (Sweden)

    Jeremy R. Dunklin

    2017-01-01

    Full Text Available Polymer films containing plasmonic nanostructures are of increasing interest for development of responsive energy, sensing, and therapeutic systems. The present work evaluates heat dissipated from power absorbed by resonant gold (Au nanoparticles (NP with negligible Rayleigh scattering cross sections randomly dispersed in polydimethylsiloxane (PDMS films. Finite element analysis (FEA of heat transport was coordinated with characterization of resonant absorption by Mie theory and coupled dipole approximation (CDA. At AuNP particle separation greater than resonant wavelength, correspondence was observed between measured and CDA-predicted optical absorption and FEA-derived power dissipation. At AuNP particle separation less than resonant wavelength, measured extinction increased relative to predicted values, while FEA-derived power dissipation remained comparable to CDA-predicted power absorption before lagging observed extinguished power at higher AuNP content and resulting particle separation. Effects of isolated particles, for example, scattering, and particle-particle interactions, for example, multiple scattering, aggregation on observed optothermal activity were evaluated. These complementary approaches to distinguish contributions to resonant heat dissipation from isolated particle absorption and interparticle interactions support design and adaptive control of thermoplasmonic materials for a variety of implementations.

  6. The Fourier transform method for infinite medium resonance absorption problems

    International Nuclear Information System (INIS)

    Menon, S.V.G.; Sahni, D.C.

    1978-01-01

    A new method, using Fourier transforms, is developed for solving the integral equation of slowing down of neutrons in the resonance region. The transformations replace the slowing down equation with a discontinuous kernel by an integral equation with a continuous kernel over the interval (-infinity, infinity). Further the Doppler broadened line shape functions have simple analytical representations in the transform variable. In the limit of zero temperature, the integral equation reduces to a second order differential equation. Accurate expressions for the zero temperature resonance integrals are derived, using the WKB method. In general, the integral equation is seen to be amenable to solution by Ganss-Hermite quadrature formule. Doppler coefficients of 238 U resonances are given and compared with Monte Carlo calculations. The method is extended to include the effect of interference between neighbouring resonances of an absorber. For the case of two interfering resonances the slowing down equation is transformed to the coupled integral equations that are amenable to solution by methods indicated earlier. Numerical results presented for the low lying thorium-232 doublet show that the Doppler coefficients of the resonances are reduced considerably because of the overlap between them. (author)

  7. High intersubband absorption in long-wave quantum well infrared photodetector based on waveguide resonance

    Science.gov (United States)

    Zheng, Yuanliao; Chen, Pingping; Ding, Jiayi; Yang, Heming; Nie, Xiaofei; Zhou, Xiaohao; Chen, Xiaoshuang; Lu, Wei

    2018-06-01

    A hybrid structure consisting of periodic gold stripes and an overlaying gold film has been proposed as the optical coupler of a long-wave quantum well infrared photodetector. Absorption spectra and field distributions of the structure at back-side normal incidence are calculated by the finite difference time-domain method. The results indicate that the intersubband absorption can be greatly enhanced based on the waveguide resonance as well as the surface plasmon polariton (SPP) mode. With the optimized structural parameters of the periodic gold stripes, the maximal intersubband absorption can exceed 80%, which is much higher than the SPP-enhanced intersubband absorption (the one of the standard device. The relationship between the structural parameters and the waveguide resonant wavelength is derived. Other advantages of the efficient optical coupling based on waveguide resonance are also discussed.

  8. Fast wave absorption at the Alfven resonance during ion cyclotron resonance heating

    International Nuclear Information System (INIS)

    Heikkinen, J.A.; Hellsten, T.; Alava, M.J.

    1991-01-01

    For ICRH scenarii where the majority cyclotron resonance intersects the plasma core, mode conversion of the fast magnetosonic wave to an Alfven wave takes place at the plasma boundary on the high field side. Simple analytical estimates of the converted power for this mode conversion process are derived and compared with numerical calculations including finite electron inertia and kinetic effects. The converted power is found to depend on the local value of the wave field as well as on plasma parameters at the Alfven wave resonance. The interference with the reflected wave will therefore modify the mode conversion. If the conversion layer is localized near the wall, the conversion will be strongly reduced. The conversion coefficient is found to be strongest for small density gradients and high density and it is sensitive to the value of the parallel wave number. Whether it increases or decreases with the latter depends on the ion composition. Analysis of this problem for ICRH in JET predicts that a large fraction of the power is mode converted at the plasma boundary for first harmonic heating of tritium in a deuterium-tritium plasma. (author). 13 refs, 10 figs, 1 tab

  9. Tunable THz wave absorption by graphene-assisted plasmonic metasurfaces based on metallic split ring resonators

    International Nuclear Information System (INIS)

    Ahmadivand, Arash; Sinha, Raju; Karabiyik, Mustafa; Vabbina, Phani Kiran; Gerislioglu, Burak; Kaya, Serkan; Pala, Nezih

    2017-01-01

    Graphene plasmonics has been introduced as a novel platform to design various nano- and microstructures to function in a wide range of spectrum from optical to THz frequencies. Herein, we propose a tunable plasmonic metamaterial in the THz regime by using metallic (silver) concentric microscale split ring resonator arrays on a multilayer metasurface composed of silica and silicon layers. We obtained an absorption percentage of 47.9% including two strong Fano resonant dips in THz regime for the purely plasmonic metamaterial without graphene layer. Considering the data of an atomic graphene sheet (with the thickness of ~0.35 nm) in both analytical and experimental regimes obtained by prior works, we employed a graphene layer under concentric split ring resonator arrays and above the multilayer metasurface to enhance the absorption ratio in THz bandwidth. Our numerical and analytical results proved that the presence of a thin graphene layer enhances the absorption coefficient of MM to 64.35%, at the highest peak in absorption profile that corresponds to the Fano dip position. We also have shown that changing the intrinsic characteristics of graphene sheet leads to shifts in the position of Fano dips and variations in the absorption efficiency. The maximum percentage of absorption (~67%) was obtained for graphene-based MM with graphene layer with dissipative loss factor of 1477 Ω. Employing the antisymmetric feature of the split ring resonators, the proposed graphene-based metamaterial with strong polarization dependency is highly sensitive to the polarization angle of the incident THz beam.

  10. Impact of MIE-Resonances on the Atmospheric Absorption of Water Clouds

    Science.gov (United States)

    Wiscombe, W.; Kinne, S.; Nussenzveig, H.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    Clouds strongly modulate radiative transfer processes in the Earth's atmosphere. Studies, which simulate bulk properties of clouds, such as absorption, require methods that accurately account for multiple scattering among individual cloud particles. Multiple scattering processes are well described by MIE-theory, if interacting particles have a spherical shape. This is a good assumption for water droplets. Thus, simulations for water clouds (especially for interactions with solar radiation) usually apply readily available MIE-codes. The presence of different drop-sizes, however, necessitates repetitive calculations for many sizes. The usual representation by a few sizes is likely to miss contributions from densely distributed, sharp resonances. Despite their usually narrow width, integrated over the entire size-spectrum of a cloud droplet distribution, the impact of missed resonances could add up. The consideration of these resonances tends to increase cloud extinction and cloud absorption. This mechanism for a larger (than by MIE-methods predicted) solar absorption has the potential to explain observational evidence of larger than predicted cloud absorption at solar wavelengths. The presentation will address the absorption impact of added resonances for typical properties of water clouds (e.g. drop size distributions, drop concentrations and cloud geometry). Special attention will be given to scenarios with observational evidence of law than simulated solar absorption; particularly if simultaneous measurements of cloud micro- and macrophysical properties are available.

  11. Optical absorption and electron spin resonance studies of Cu in ...

    Indian Academy of Sciences (India)

    Unknown

    Na2O–50B2O3–10As2O3 glasses. In this paper, we report the ESR and optical absorption spectra of Cu2+ ions in xLi2O–(40 – x)Na2O–50B2O3–. 10As2O3 glasses. The values of x were adjusted so that the compositional parameter defined as ...

  12. Anomalous non-resonant microwave absorption in SmFeAs(O,F) polycrystalline sample

    Energy Technology Data Exchange (ETDEWEB)

    Onyancha, R.B., E-mail: 08muma@gmail.com [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg, 1710 (South Africa); Shimoyama, J. [Department of Applied Chemistry, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo (Japan); Singh, S.J. [Leibniz-Institute for Solid State and Materials Research, IFW-Dresden, D-01171 Dresden (Germany); Hayashi, K.; Ogino, H. [Department of Applied Chemistry, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo (Japan); Srinivasu, V.V. [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg, 1710 (South Africa)

    2017-02-15

    Highlights: • The non-resonant microwave absorption (NRMA) line shape in evolved with microwave power. • Observed a cross over from ‘normal’ absorption to ‘anomalous’ absorption as a function of microwave power. • The anomalous absorption has been explained in the context of non-hysteretic Josephson junction. - Abstract: Here we present the non-resonant microwave absorption (NRMA) studies on SmFeAsO{sub 0.88}F{sub 0.12} polycrystalline sample measured at 6.06 K with the magnetic field swept from −250 G to +250 G at a frequency of 9.45 GHz. It was observed that the (NRMA) line shape evolves as a function of microwave power. Again, the signal intensity increases from 22.83 µW to 0.710 mW where it reaches a maximum and quite remarkably it changed from ‘normal’ absorption to ‘anomalous’ absorption at 2.247 mW, then the intensity decreases with further increase of microwave power. The crossover from ‘normal’ to ‘anomalous’ NRMA absorption and its dependence on microwave power is a new phenomenon in iron pnictides superconductors and we have attributed this anomaly to come from non-hysteretic Josephson junction.

  13. measurements of the absorption resonance integrals by reactor oscillator method

    International Nuclear Information System (INIS)

    Markovic, V.; Kocic, A.

    1965-12-01

    Experimental values of resonance integrals for silver vary significantly dependent on authors. That is why we have chosen this sample to measure RI. On the other hand, nuclear fuel (for example natural uranium) still represents an interesting objective for research in reactor physics. Measurements of natural uranium are done as a function of S/M. Measurements were done by amplitude reactor oscillator ROB-1/5 with precision from 0.5% - 2% dependent on the conditions of the oscillator. Measurements were completed at the heavy water reactor RB with 2% enriched uranium fuel [fr

  14. Electron volt spectroscopy on a pulsed neutron source using resonance absorption filters

    International Nuclear Information System (INIS)

    Newport, R.J.; Williams, W.G.

    1983-05-01

    The design aspects of an inelastic neutron spectrometer based on energy selection by the resonance absorption filter difference method are discussed. Detailed calculations of the accessible dynamical range (Q, ω), energy and momentum transfer resolutions and representative count rates are presented for Sm and Ta resonance filters in an inverse geometry spectrometer on a high intensity pulsed source such as the RAL Spallation Neutron Source (SNS). A discussion is given of the double-difference method, which provides a means of improving the resonance attenuation peak shape. As a result of this study, as well as preliminary experimental results, recommendations are made for the future development of the technique. (author)

  15. Coal thickness gauge using RRAS techniques, part 1. [radiofrequency resonance absorption

    Science.gov (United States)

    Rollwitz, W. L.; King, J. D.

    1978-01-01

    A noncontacting sensor having a measurement range of 0 to 6 in or more, and with an accuracy of 0.5 in or better is needed to control the machinery used in modern coal mining so that the thickness of the coal layer remaining over the rock is maintained within selected bounds. The feasibility of using the radiofrequency resonance absorption (RRAS) techniques of electron magnetic resonance (EMR) and nuclear magnetic resonance (NMR) as the basis of a coal thickness gauge is discussed. The EMR technique was found, by analysis and experiments, to be well suited for this application.

  16. Observation of electromagnetically induced transparency and absorption in Yttrium Iron Garnet loaded split ring resonator

    Science.gov (United States)

    Tay, Z. J.; Soh, W. T.; Ong, C. K.

    2018-04-01

    In this paper, we propose a new method of controlling microwave transmission from Electromagnetically Induced Absorption (EIA) to Electromagnetically Induced Transparency (EIT). EIA describes the state where the system strongly absorbs microwaves, whereas EIT describes the state in which the system is transparent to microwaves. Control is achieved via coupling of the 3 GHz photon mode of a metamaterial Split Ring Resonator (SRR) to the spin wave magnon modes of a Yttrium Iron Garnet (YIG) bulk. The system is described by a 2-body interaction matrix with an additional fitting parameter τ which takes into account the fact that the microstrip feed line could excite the SRR as well as the YIG. The parameter τ reveals the effect of geometry and shielding on the coupling behaviour and gives rise to unique physics. In low τ (τ ⩽ 2) configurations, only EIT is reported. However, in high τ (τ ≈ 10) configurations, EIA is reported. Furthermore, we report that the system can be easily changed from a low τ to high τ configuration by shielding the SRR from the microstrip with a thin metal piece. Varying the τ parameter through shielding is thus proposed as a new method of controlling the microwave transmission at the coupling region.

  17. Iota-dependent resonance absorption in the optical model description of alpha particle elastic scattering

    International Nuclear Information System (INIS)

    Chyla, K.; Jarczyk, L.; Maciuk, B.; Zipper, W.

    1976-01-01

    Alpha particle scattering from 28 Si has been studied at five bombarding energies from 23.5 to 28.5 MeV. iota-dependent resonance absorption has been introduced to the optical model analysis of 28 Si (α,β) 28 Si reaction. (author)

  18. Profile modification and hot electron temperature from resonant absorption at modest intensity

    International Nuclear Information System (INIS)

    Albritton, J.R.; Langdon, A.B.

    1980-01-01

    Resonant absorption is investigated in expanding plasmas. The momentum deposition associated with the ejection of hot electrons toward low density via wavebreaking readily exceeds that of the incident laser radiation and results in significant modification of the density profile at critical. New scaling of hot electron temperature with laser and plasma parameters is presented

  19. A Novel Approach to Resonant Absorption of the Fast Magnetohydrodynamic Eigenmodes of a Coronal Arcade

    Science.gov (United States)

    Hindman, Bradley W.; Jain, Rekha

    2018-05-01

    The arched field lines forming coronal arcades are often observed to undulate as magnetohydrodynamic waves propagate both across and along the magnetic field. These waves are most likely a combination of resonantly coupled fast magnetoacoustic waves and Alfvén waves. The coupling results in resonant absorption of the fast waves, converting fast wave energy into Alfvén waves. The fast eigenmodes of the arcade have proven difficult to compute or derive analytically, largely because of the mathematical complexity that the coupling introduces. When a traditional spectral decomposition is employed, the discrete spectrum associated with the fast eigenmodes is often subsumed into the continuous Alfvén spectrum. Thus fast eigenmodes become collective modes or quasi-modes. Here we present a spectral decomposition that treats the eigenmodes as having real frequencies but complex wavenumbers. Using this procedure we derive dispersion relations, spatial damping rates, and eigenfunctions for the resonant, fast eigenmodes of the arcade. We demonstrate that resonant absorption introduces a fast mode that would not exist otherwise. This new mode is heavily damped by resonant absorption, travelling only a few wavelengths before losing most of its energy.

  20. Effect of an additional magnetic field on Hanle-type absorption resonances

    International Nuclear Information System (INIS)

    Singh Grewal, Raghwinder; Pattabiraman, M

    2014-01-01

    We computationally compare Hanle-type resonances for a F g =1→F e =0 transition of the 87 RbD 2 line for magnetic field scans parallel (longitudinal scan) and perpendicular (transverse scan) to the direction of propagation of the optical field in the presence of an additional transverse magnetic field (TMF). For a linearly polarized light, the coherent population trapping (CPT) resonances split at line centre and are identical for both longitudinal and transverse scans. When the probe beam ellipticity is varied, the effect of the TMF is found to be opposite for longitudinal and transverse scans. For a longitudinal scan, the splitting observed in the CPT resonance evolves into an enhanced absorption resonance with an increase in ellipticity. For a transverse scan, the splitting vanishes at higher ellipticities. This can be understood in terms of population redistribution in the ground state sublevels and near-neighbor ground state coherences created by the TMF. We also show that the enhanced absorption signal that splits the CPT resonance strongly depends on transit time, and the CPT resonance strength depends on the excited state dephasing rate. (paper)

  1. Long-term water absorption tests for frost insulation materials taking into account frost attack

    Directory of Open Access Journals (Sweden)

    Toni A. Pakkala

    2014-01-01

    Full Text Available Water absorption of several different frost insulation materials was tested for four years. The test took into account both immersion and frost attack to materials. On the basis of the research the water absorption on XPS specimens is significantly minor compared to EPS specimens that were studied. The most significant result was that freezing of test specimens did not affect on water absorption of XPS specimens but had a major effect on water absorption of EPS specimens. With frozen EPS specimen the absorption continued increasing even after 48 months of immersion. Presumably the reason for such a behaviour is that the pore structure of EPS is not able to resist the tension caused by freezing water and therefore cracks are formed. Thus, more water absorbs inside the EPS through the cracks and it causes cracking deeper in the specimen which is why absorption increases after every freezing period.

  2. Resonant Absorption in GaAs-Based Nanowires by Means of Photo-Acoustic Spectroscopy

    Science.gov (United States)

    Petronijevic, E.; Leahu, G.; Belardini, A.; Centini, M.; Li Voti, R.; Hakkarainen, T.; Koivusalo, E.; Guina, M.; Sibilia, C.

    2018-03-01

    Semiconductor nanowires made of high refractive index materials can couple the incoming light to specific waveguide modes that offer resonant absorption enhancement under the bandgap wavelength, essential for light harvesting, lasing and detection applications. Moreover, the non-trivial ellipticity of such modes can offer near field interactions with chiral molecules, governed by near chiral field. These modes are therefore very important to detect. Here, we present the photo-acoustic spectroscopy as a low-cost, reliable, sensitive and scattering-free tool to measure the spectral position and absorption efficiency of these modes. The investigated samples are hexagonal nanowires with GaAs core; the fabrication by means of lithography-free molecular beam epitaxy provides controllable and uniform dimensions that allow for the excitation of the fundamental resonant mode around 800 nm. We show that the modulation frequency increase leads to the discrimination of the resonant mode absorption from the overall absorption of the substrate. As the experimental data are in great agreement with numerical simulations, the design can be optimized and followed by photo-acoustic characterization for a specific application.

  3. Synthesis, multi-nonlinear dielectric resonance and electromagnetic absorption properties of hcp-cobalt particles

    International Nuclear Information System (INIS)

    Wen, Shulai; Liu, Ying; Zhao, Xiuchen; Cheng, Jingwei; Li, Hong

    2014-01-01

    Hcp-cobalt particles were successfully prepared by a liquid phase reduction method, and the microstructure, static magnetic properties, electromagnetic and microwave absorption properties of the cobalt particles with irregular shape were investigated in detail. The measured results indicate that the saturation magnetization was less than that of hcp-Co single crystals, and the coercivity was larger than that of bulk cobalt crystal. The permittivity presents multi-nonlinear dielectric resonance, which may result from the irregular shape containing parts of cutting angle of dodecahedron of cobalt particles. The real part of permeability decreases with the frequency, and the imaginary part has a wide resonant peak. The paraffin-based composite containing 70 wt% cobalt particles possessed strong absorption characteristics with a minimum RL of −38.97 dB at 10.81 GHz and an absorption band with RL under −10 dB from 8.72 to 13.26 GHz when the thickness is 1.8 mm, which exhibits excellent microwave absorption in middle and high frequency. The architectural design of material morphologies is important for improving microwave absorption properties toward future application. - Highlights: • Hcp-cobalt particles were prepared by a liquid phase reduction method. • The saturation magnetization was less than that of hcp-Co single crystals. • The permittivity presents multi-nonlinear dielectric resonance. • The real part of permeability decreases with frequency, and the imaginary part presents a wide resonant peak. • The paraffin-based composite possessed a minimum RL of −38.97 dB at 10.81 GHz

  4. RICM, Resonance Absorption in Multi-Region Slab or Square or Hexagonal Lattice

    International Nuclear Information System (INIS)

    Mizuta, H.; Aoyama, K.; Fukai, Y.

    1968-01-01

    1 - Nature of physical problem solved: Calculates the resonance absorption integral of resonant isotope in a multi-region lattice using the first flight collision probability. The lattice configurations considered are a slab lattice, a square or hexagonal lattice and a cylindricalized lattice with isotropic or perfect reflecting boundary condition. Cases for an isolated rod or plate and homogeneous system can also be treated. 2 - Method of solution: Slowing down of neutrons by each isotope in each region is solved by either exact numerical integration of the slowing down equation or narrow - or wide-resonance approximation. Breit-Wigner's single level formula is used for the resonance cross section and Porter-Thomas distribution of neutron width is taken into account in the unresolved region. 3 - Restrictions on the complexity of the problem: Maximum number of regions: 5; Maximum Number of groups: 100

  5. Heavy nucleus resonant absorption in heterogeneous lattices. I- Apollo 2 self-shielding formalism; Absorption resonnante des noyaux lourds dans les reseaux heterogenes. I -Formalisme du module d`autoprotection d`Apollo 2

    Energy Technology Data Exchange (ETDEWEB)

    Coste, M.

    1994-01-01

    This note gives in detailed way the self-shielding formalism which is used in the multigroup transport code APOLLO2. The self-shielded cross-sections are performed with the same scheme as in APOLLO1. We use two equivalencies, first an heterogeneous/homogeneous equivalence which gives the reaction rates and then a multigroup equivalence in order to obtain the cross-sections which preserve these reaction rates. However, numerous improvements were implemented, specially in the homogenization step. Homogenization can be performed group per group with different modelizations of the heavy slowing-down operator (statistical, intermediary and ``wide resonance`` models), which allows us to fit correctly the resonance shapes. Moreover, we can take exactly into account the spatial interferences between resonant isotopes with the background matrix model. Consequently, we are now able to perform, for instance, the radial distribution of the resonant absorption inside a fuel pin. (author). 7 refs., 3 figs.

  6. Broadband perfect infrared absorption by tuning epsilon-near-zero and epsilon-near-pole resonances of multilayer ITO nanowires.

    Science.gov (United States)

    Zhou, Kun; Cheng, Qiang; Song, Jinlin; Lu, Lu; Jia, Zhihao; Li, Junwei

    2018-01-01

    We numerically investigate the broadband perfect infrared absorption by tuning epsilon-near-zero (ENZ) and epsilon-near-pole (ENP) resonances of multilayer indium tin oxide nanowires (ITO NWs). The monolayer ITO NWs array shows intensive absorption at ENZ and ENP wavelengths for p polarization, while only at the ENP wavelength for s polarization. Moreover, the ENP resonances are almost omnidirectional and the ENZ resonances are angularly dependent. Therefore, the absorption bandwidth is broader for p polarization than that for s polarization when polarized waves are incident obliquely. The ENZ resonances can be tuned by altering the doping concentration and volume filling factor of ITO NWs. However, the ENP resonances only can be tuned by changing the doping concentration of ITO NWs, and volume filling factor impacts little on the ENP resonances. Based on the strong absorption properties of each layer at their own ENP and ENZ resonances, the tuned absorption of the bilayer ITO NWs with the different doping concentrations can be broader and stronger. Furthermore, multilayer ITO NWs can achieve broadband perfect absorption by controlling the doping concentration, volume filling factor, and length of the NWs in each layer. This study has the potential to apply to applications requiring efficient absorption and energy conversion.

  7. The effect of background absorption on the compound cross-section in resonance scattering

    International Nuclear Information System (INIS)

    Frenkel, A.

    1976-01-01

    The effect of channel-channel correlations in the compound cross-section is studied in a model of a resonance above a compound background characterized by equal absorption in all open channels. A general rule which cannot be derived from unitarity alone is proved for the fluctuating cross-section. It provides new understanding of level-level correlations in scattering through compound nucleus states. (author)

  8. Proton emission from resonant laser absorption and self-focusing effects from hydrogenated structures

    Czech Academy of Sciences Publication Activity Database

    Cutroneo, M.; Torrisi, L.; Margarone, Daniele; Picciotto, A.

    2013-01-01

    Roč. 272, May (2013), s. 50-54 ISSN 0169-4332 R&D Projects: GA MŠk EE.2.3.20.0087 Grant - others:OP VK 2 LaserGen(XE) CZ.1.07/2.3.00/20.0087 Institutional support: RVO:68378271 Keywords : resonant absorption * self-focusing * Thomson parabola * spectrometer Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.538, year: 2013

  9. Prototype explosives detection system based on nuclear resonance absorption in nitrogen

    International Nuclear Information System (INIS)

    Morgado, R.E.; Arnone, G.J.; Cappiello, C.C.

    1996-01-01

    A laboratory prototype system has been developed for the experimental evaluation of an explosives detection technique based on nuclear resonance absorption of gamma rays in nitrogen. Major subsystems include a radiofrequency quadrupole proton accelerator and associated beam transport system, a high-power gamma-ray production target, an airline-luggage tomographic inspection system, and an image- processing/detection-alarm subsystem. The detection system performance, based on a limited experimental test, is reported

  10. Semi-analytical model of laser resonance absorption in plasmas with a parabolic density profile

    International Nuclear Information System (INIS)

    Pestehe, S J; Mohammadnejad, M

    2010-01-01

    Analytical expressions for mode conversion and resonance absorption of electromagnetic waves in inhomogeneous, unmagnetized plasmas are required for laboratory and simulation studies. Although most of the analyses of this problem have concentrated on the linear plasma density profile, there are a few research works that deal with different plasma density profiles including the parabolic profile. Almost none of them could give clear analytical formulae for the electric and magnetic components of the electromagnetic field propagating through inhomogeneous plasmas. In this paper, we have considered the resonant absorption of laser light near the critical density of plasmas with parabolic electron density profiles followed by a uniform over-dense region and have obtained expressions for the electric and magnetic vectors of laser light propagating through the plasma. An estimation of the fractional absorption of laser energy has also been carried out. It has been shown that, in contrast to the linear density profile, the energy absorption depends explicitly on the value of collision frequency as well as on a new parameter, N, called the over-dense density order.

  11. High-quality electromagnetically-induced absorption resonances in a buffer-gas-filled vapour cell

    Science.gov (United States)

    Brazhnikov, D. V.; Ignatovich, S. M.; Vishnyakov, V. I.; Skvortsov, M. N.; Andreeva, Ch; Entin, V. M.; Ryabtsev, I. I.

    2018-02-01

    Magneto-optical subnatural-linewidth resonances of electromagnetically-induced absorption (EIA) in an alkali vapour cell have been experimentally studied. The observation configuration includes using two counter-propagating pumps and probe light waves with mutually orthogonal linear polarizations, exciting an open optical transition in the 87Rb D 1 line in the presence of argon buffer gas. The EIA signals registered in a probe-wave transmission reach an unprecedented contrast of about 135% with respect to the wide ‘Doppler’ absorption pedestal and 29% with respect to the level of background transmission signal. These contrast values correspond to a relatively small resonance full width at half maximum of about 7.2 mG (5.2 kHz). The width of the narrowest EIA resonance observed is about 2.1 mG (1.5 kHz). To our knowledge, such a large relative contrast at the kHz-width is the record result for EIA resonances. In general, the work has experimentally proved that the magneto-optical scheme used has very good prospects for various quantum technologies (quantum sensors of weak magnetic fields, optical switches and other photonic elements).

  12. Compact extended model for doppler broadening of neutron absorption resonances in solids

    International Nuclear Information System (INIS)

    Villanueva, A. J; Granada, J.R

    2009-01-01

    We present a simplified compact model for calculating Doppler broadening of neutron absorption resonances in an incoherent Debye solid. Our model extends the effective temperature gas model to cover the whole range of energies and temperatures, and reduces the information of the dynamical system to a minimum content compatible with a much better accuracy of the calculation. This model is thus capable of replacing the existing algorithm in standard codes for resonance cross sections preparation aimed at neutron and reactor physics calculations. The model is applied to the 238 U 6.671 eV effective broadened cross section. We also show how this model can be used for thermometry in an improved fashion compared to the effective temperature gas model. Experimental data of the same resonance at low and high temperatures are also shown and the performances of each model are put to the test on this basis. [es

  13. Non-destructive studies of fuel pellets by neutron resonance absorption radiography and thermal neutron radiography

    Energy Technology Data Exchange (ETDEWEB)

    Tremsin, A.S., E-mail: ast@ssl.berkeley.edu [University of California, Berkeley, CA 94720 (United States); Vogel, S.C.; Mocko, M.; Bourke, M.A.M.; Yuan, V.; Nelson, R.O.; Brown, D.W. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Feller, W.B. [NOVA Scientific, Inc., 10 Picker Rd., Sturbridge, MA 01566 (United States)

    2013-09-15

    Many isotopes in nuclear materials exhibit strong peaks in neutron absorption cross sections in the epithermal energy range (1–1000 eV). These peaks (often referred to as resonances) occur at energies specific to particular isotopes, providing a means of isotope identification and concentration measurements. The high penetration of epithermal neutrons through most materials is very useful for studies where samples consist of heavy-Z elements opaque to X-rays and sometimes to thermal neutrons as well. The characterization of nuclear fuel elements in their cladding can benefit from the development of high resolution neutron resonance absorption imaging (NRAI), enabled by recently developed spatially-resolved neutron time-of-flight detectors. In this technique the neutron transmission of the sample is measured as a function of spatial location and of neutron energy. In the region of the spectra that borders the resonance energy for a particular isotope, the reduction in transmission can be used to acquire an image revealing the 2-dimensional distribution of that isotope within the sample. Provided that the energy of each transmitted neutron is measured by the neutron detector used and the irradiated sample possesses neutron absorption resonances, then isotope-specific location maps can be acquired simultaneously for several isotopes. This can be done even in the case where samples are opaque or have very similar transmission for thermal neutrons and X-rays or where only low concentrations of particular isotopes are present (<0.1 atom% in some cases). Ultimately, such radiographs of isotope location can be utilized to measure isotope concentration, and can even be combined to produce three-dimensional distributions using tomographic methods. In this paper we present the proof-of-principle of NRAI and transmission Bragg edge imaging performed at Flight Path 5 (FP5) at the LANSCE pulsed, moderated neutron source of Los Alamos National Laboratory. A set of urania mockup

  14. Nuclear resonance absorption (NRA): method and application to detection of contraband in a baggage, cargo and vehicles

    International Nuclear Information System (INIS)

    Goldenberg, M.B.; Vartsky, D.; Engler, G.

    1996-01-01

    Nuclear Resonance Absorption (NRA) has played a prominent role in nuclear spectroscopy for almost 5 decades, but found only few and marginal applications outside the laboratory before 1985. In that year the situation changed markedly when scientists from this laboratory proposed to the Federal Aviation Administration (FAA) in the U.S. to study its suitability for detecting explosives in passenger baggage via nitrogen-specific radiographic imaging (explosives, as a category, have inordinately high nitrogen densities). Following a basic feasibility study and the first laboratory demonstration of explosives detection in 1989, this project has attained the stage of a pre-industrial prototype that exhibited excellent performance characteristics in a 1993 blind test conducted by the FAA. In terms of NRA operational system concept, data taking methodology, development of dedicated detectors and image analysis algorithms, the Soreq group has made a major, if not exclusive, contribution over the years. (authors)

  15. Multiproton final states in positive pion absorption below the Δ(1232) resonance

    International Nuclear Information System (INIS)

    Giannelli, R. A.; Ritchie, B. G.; Applegate, J. M.; Beck, E.; Beck, J.; Vanderpool, A. O.; Morris, C. L.; Rahwool-Sullivan, M.; Jones, M. K.; Ransome, R. D.

    2000-01-01

    Inclusive cross sections for positive pion absorption leading to final states including two or more protons have been measured with a large solid angle detector for incident pion energies from 30 to 135 MeV for targets with A=2-208. The mass dependences for the inclusive (π + ,2p), (π + ,3p), and total absorption cross sections for multiproton final states were found to be proportional to A n with n≅0.5. These cross sections also were observed to have an energy dependence at energies below 150 MeV reflective of the importance of the Δ(1232) resonance, similar to that observed for πd→pp. The inclusive cross sections for (π + ,4p) were found to be less than 10 mb for all targets at all energies. Estimates were also obtained for cross sections for pion absorption leading to 2p1n and 3p1n final states. Quasideuteron absorption contributions increase slowly with A, and the energy dependence of those contributions mirrors that for πd→pp. The data obtained here for multiproton final states indicate that a significant fraction of absorption events, increasing with A, most likely arises from final states containing fewer than two protons. (c) 2000 The American Physical Society

  16. How to take absorptive surfaces into account when designing outdoor sound reinforcement systems

    DEFF Research Database (Denmark)

    Rasmussen, Karsten bo

    1996-01-01

    When sound reinforcement systems are used outdoors, absorptive surfaces are usually present along the propagation path of the sound. This may lead to a very significant colouration of the spectrum received by the audience. The colouration depends on the location and directivity of the loudspeaker......, the nature of the absorptive surface (eg grass) and the location of the audience. It is discussed how this effect may be calculated and numerical examples are shown. The results show a significant colouration and attenuation of the sound due to grass-covered surfaces....

  17. Detailed resonance absorption calculations with the Monte Carlo code MCNP and collision probability version of the slowing down code ROLAIDS

    International Nuclear Information System (INIS)

    Kruijf, W.J.M. de; Janssen, A.J.

    1994-01-01

    Very accurate Mote Carlo calculations with Monte Carlo Code have been performed to serve as reference for benchmark calculations on resonance absorption by U 238 in a typical PWR pin-cell geometry. Calculations with the energy-pointwise slowing down code calculates the resonance absorption accurately. Calculations with the multigroup discrete ordinates code XSDRN show that accurate results can only be achieved with a very fine energy mesh. (authors). 9 refs., 5 figs., 2 tabs

  18. Advances in gamma ray resonant scattering and absorption long-lived isomeric nuclear states

    CERN Document Server

    Davydov, Andrey V

    2015-01-01

    This book presents the basics and advanced topics of research of gamma ray physics. It describes measuring of  Fermi surfaces with gamma resonance spectroscopy and the theory of angular distributions of resonantly scattered gamma rays. The dependence of excited-nuclei average lifetime on the shape of the exciting-radiation spectrum and electron binding energies in the spectra of scattered gamma rays is described. Resonant excitation by gamma rays of nuclear isomeric states with long lifetime leads to the emission and absorption lines. In the book, a new gamma spectroscopic method, gravitational gamma spectrometry, is developed. It has a resolution hundred million times higher than the usual Mössbauer spectrometer. Another important topic of this book is resonant scattering of annihilation quanta by nuclei with excited states in connection with positron annihilation. The application of the methods described is to explain the phenomenon of Coulomb fragmentation of gamma-source molecules and resonant scatt...

  19. Tunable absorption resonances in the ultraviolet for InP nanowire arrays.

    Science.gov (United States)

    Aghaeipour, Mahtab; Anttu, Nicklas; Nylund, Gustav; Samuelson, Lars; Lehmann, Sebastian; Pistol, Mats-Erik

    2014-11-17

    The ability to tune the photon absorptance spectrum is an attracting way of tailoring the response of devices like photodetectors and solar cells. Here, we measure the reflectance spectra of InP substrates patterned with arrays of vertically standing InP nanowires. Using the reflectance spectra, we calculate and analyze the corresponding absorptance spectra of the nanowires. We show that we can tune absorption resonances for the nanowire arrays into the ultraviolet by decreasing the diameter of the nanowires. When we compare our measurements with electromagnetic modeling, we generally find good agreement. Interestingly, the remaining differences between modeled and measured spectra are attributed to a crystal-phase dependence in the refractive index of InP. Specifically, we find indication of significant differences in the refractive index between the modeled zinc-blende InP nanowires and the measured wurtzite InP nanowires in the ultraviolet. We believe that such crystal-phase dependent differences in the refractive index affect the possibility to excite optical resonances in the large wavelength range of 345 InP nanowire-based solar cells and photodetectors.

  20. Probing ultrafast ππ*/nπ* internal conversion in organic chromophores via K-edge resonant absorption

    DEFF Research Database (Denmark)

    Wolf, T. J. A.; Myhre, Rolf H.; Cryan, J. P.

    2017-01-01

    -edge soft X-ray absorption spectroscopy. As a hole forms in the n orbital during ππ*/nπ* internal conversion, the absorption spectrum at the heteroatom K-edge exhibits an additional resonance. We demonstrate the concept using the nucleobase thymine at the oxygen K-edge, and unambiguously show that ππ...

  1. Numerical examinations of simplified spondylodesis models concerning energy absorption in magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Hadert Nicole

    2016-09-01

    Full Text Available Metallic implants in magnetic resonance imaging (MRI are a potential safety risk since the energy absorption may increase temperature of the surrounding tissue. The temperature rise is highly dependent on implant size. Numerical examinations can be used to calculate the energy absorption in terms of the specific absorption rate (SAR induced by MRI on orthopaedic implants. This research presents the impact of titanium osteosynthesis spine implants, called spondylodesis, deduced by numerical examinations of energy absorption in simplified spondylodesis models placed in 1.5 T and 3.0 T MRI body coils. The implants are modelled along with a spine model consisting of vertebrae and disci intervertebrales thus extending previous investigations [1], [2]. Increased SAR values are observed at the ends of long implants, while at the center SAR is significantly lower. Sufficiently short implants show increased SAR along the complete length of the implant. A careful data analysis reveals that the particular anatomy, i.e. vertebrae and disci intervertebrales, has a significant effect on SAR. On top of SAR profile due to the implant length, considerable SAR variations at small scale are observed, e.g. SAR values at vertebra are higher than at disc positions.

  2. A comparison of neutron resonance absorption in thermal reactor lattices in the AUS neutronics code system with Monte Carlo calculations

    International Nuclear Information System (INIS)

    Robinson, G.S.

    1985-08-01

    The calculation of resonance shielding by the subgroup method, as incorporated in the MIRANDA module of the AUS neutronics code system, is compared with Monte Carlo calculatons for a number of thermal reactor lattices. For the large range of single rod and rod cluster lattices considered, AUS results for resonance absorption were high by up to two per cent

  3. Recent Results of Search for Solar Axions Using Resonant Absorption by 83Kr nuclei

    Science.gov (United States)

    Derbin, A. V.; Drachnev, I. S.; Gangapshev, A. M.; Gavrilyuk, Yu M.; Kazalov, V. V.; Kobychev, V. V.; Kuzminov, V. V.; Muratova, V. N.; Panashenko, S. I.; Ratkevich, S. S.; Tekueva, D. A.; Unzhakov, E. V.; Yakimenko, S. P.

    2017-12-01

    A search for resonant absorption of the solar axion by 83Kr nuclei was performed using the proportional counter installed inside the low-background setup at the Baksan Neutrino Observatory. The obtained model independent upper limit on the combination of isoscalar and isovector axion-nucleon couplings |g 3 - g 0| ≤ 8.4 × 10-7 allowed us to set the new upper limit on the hadronic axion mass of mA ≤ 65 eV (95% C.L.) with the generally accepted values S=0.5 and z=0.56.

  4. Experimental study of neutron-optical potential with absorption using Fabry-Perot magnetic resonator

    International Nuclear Information System (INIS)

    Hino, M.; Tasaki, S.; Ebisawa, T.; Kawai, T.; Achiwa, N.; Yamazaki, D.

    1999-01-01

    Complete text of publication follows. Recently spin precession angles of neutrons tunneling and non-tunneling through [Permalloy45(PA)-germanium(Ge)]-PA Fabry-Perot magnetic resonator have been observed [1]. The spin precession angle is well reproduced by the theoretical phase difference of up and down spin neutron wave function based on one-dimensional Schroedinger equation using optical potential model [2]. Spin precession angle and transmission probability of neutron through PA-(Ge/Gd)-PA Fabry-Perot magnetic resonator are presented, where the gap(Ge/Gd) layer consists of germanium and gadolinium atoms, and the optical potential model for magnetic multilayer system with absorption is discussed. (author) [1] M. Hino, et al., Physica B 241-243, 1083 (1998).; [2] S. Yamada, et al., Annu. Rep. Res. Reactor Inst. Kyoto Univ. 11, 8 (1978)

  5. Studies of the Effective Total and Resonance Absorption Cross Sections for Zircaloy 2 and Zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Hellstrand, E; Lindahl, G; Lundgren, G

    1961-06-15

    Using pile oscillator technique, the total absorption cross section for zircaloy 2 plates has been determined in the neutron spectrum of the reactor R1. The plate thickness was varied in six steps from 0. 2 mm to 6. 4 mm. The thermal cross section for the alloy was calculated from cross section data and the known composition of the alloy. By subtracting this value from the measured cross sections and dividing by the factor {alpha}=2/{radical}({pi}) x r x {radical}(T/T{sub 0}) the effective resonance integrals were obtained. After subtraction of a constant amount for resonance contributions from hafnium, tin etc., effective resonance integrals for zirconium could be evaluated. An extrapolated value of 0.85 {+-} 0.15 b was obtained for the infinitely dilute integral (l/v part excluded). The ratio of the resonance integral at plate thicknesses 0.2 and 6.4 mm came out as 1.65 {+-} 0.25.

  6. Interband optical absorption in the Wannier-Stark ladder under the electron-LO-phonon resonance condition

    International Nuclear Information System (INIS)

    Govorov, A.O.

    1993-08-01

    Interband optical absorption in the Wannier-Stark ladder in the presence of the electron-LO-phonon resonance is investigated theoretically. The electron-LO-phonon resonance occurs when the energy spacing between adjacent Stark-ladder levels coincides with the LO-phonon energy. We propose a model describing the polaron effect in a superlattice. Calculations show that the absorption line shape is strongly modified due to the polaron effect under the electron-LO-phonon resonance condition. We consider optical phenomena in a normal magnetic field that leads to enhancement of polaron effects. (author). 17 refs, 5 figs

  7. Pulse-bandwidth dependence of coherent phase control of resonance-mediated (2+1) three-photon absorption

    International Nuclear Information System (INIS)

    Gandman, Andrey; Chuntonov, Lev; Rybak, Leonid; Amitay, Zohar

    2007-01-01

    We study in detail coherent phase control of femtosecond resonance-mediated (2+1) three-photon absorption and its dependence on the spectral bandwidth of the excitation pulse. The regime is the weak-field regime of third perturbative order. The corresponding interference mechanism involves a group of three-photon excitation pathways that are on resonance with the intermediate state and a group of three-photon excitation pathways that are near resonant with it. The model system of the study is atomic sodium (Na), for which experimental and numerical-theoretical results are obtained. Prominent among the results is our finding that with simple proper pulse shaping an increase in the excitation bandwidth leads to a corresponding increase in the enhancement of the three-photon absorption over the absorption induced by the (unshaped) transform-limited pulse. For example, here, a 40 nm bandwidth leads to an order-of-magnitude enhancement over the transform-limited absorption

  8. Wideband RCS Reduction of Microstrip Array Antenna Based on Absorptive Frequency Selective Surface and Microstrip Resonators

    Directory of Open Access Journals (Sweden)

    Jingjing Xue

    2017-01-01

    Full Text Available An approach for wideband radar cross section (RCS reduction of a microstrip array antenna is presented and discussed. The scheme is based on the microstrip resonators and absorptive frequency selective surface (AFSS with a wideband absorptive property over the low band 1.9–7.5 GHz and a transmission characteristic at high frequency 11.05 GHz. The AFSS is designed to realize the out-of-band RCS reduction and preserve the radiation performance simultaneously, and it is placed above the antenna with the operating frequency of 11.05 GHz. Moreover, the microstrip resonators are loaded to obtain the in-band RCS reduction. As a result, a significant RCS reduction from 1.5 GHz to 13 GHz for both types of polarization has been accomplished. Compared with the reference antenna, the simulated results exhibit that the monostatic RCS of the proposed array antenna in x- and y-polarization can be reduced as much as 17.6 dB and 21.5 dB, respectively. And the measured results agree well with the simulated ones.

  9. Synthetic model for Doppler broadening of neutron absorption resonances in molecular fluids

    Energy Technology Data Exchange (ETDEWEB)

    Villanueva, Alejandro J., E-mail: villanueva@cab.cnea.gov.a [Comision Nacional de Energia Atomica, Centro Atomico Bariloche and Instituto Balseiro, 8400 S.C. de Bariloche (RN) (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Granada, J.R. [Comision Nacional de Energia Atomica, Centro Atomico Bariloche and Instituto Balseiro, 8400 S.C. de Bariloche (RN) (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina)

    2010-08-15

    A general and systematic approach expressed in modern language, accounting for molecular motion effects on Doppler Broadening of Neutron Absorption Resonances (DBNAR) is given the form of a new model. It relies on well validated hypothesis: The separability of atomic from nuclear degrees of freedom, the use of the Van Hove scattering formalism and the fact that a conceptually identical approach produced experimentally proved predictions when applied to DBNAR in solid systems. We treat the molecular internal degrees of freedom approximately as harmonic oscillators. As a second contribution of this work, a synthetic model is presented in order to make the more complete model mentioned above suitable for neutron calculation codes. This second synthetic model reduces to the exact expressions of the complete model in the low and high neutron energy regimes and provides a plausible transition in between. Numerical results are presented for a general hypothetical case to show its strengths and limitations. Also, both models are applied to a real case of the {sup 238}U 6.674 eV resonant effective broadened absorption cross-section in UF6 (uranium hexafluoride). A direct experimental validation of our models is still necessary for which a special high resolution neutron transmission experiment ought to be devised at low temperatures and pressures on a gaseous system. It is showed how the synthetic model can be used to make thermometric predictions in an improved fashion in comparison to the effective temperature gas model at low temperatures.

  10. Distribution and absorption of local anesthetics in inferior alveolar nerve block: evaluation by magnetic resonance imaging.

    Science.gov (United States)

    Ay, Sinan; Küçük, Dervisşhan; Gümüş, Cesur; Kara, M Isa

    2011-11-01

    The aim of this study was to evaluate the distribution and absorption of local anesthetic solutions in inferior alveolar nerve block using magnetic resonance imaging. Forty healthy volunteers were divided into 4 groups and injected with 1.5 mL for inferior alveolar nerve block and 0.3 mL for lingual nerve block. The solutions used for the different groups were 2% lidocaine, 2% lidocaine with 0.125 mg/mL epinephrine, 4% articaine with 0.006 mg/mL epinephrine, and 4% articaine with 0.012 mg/mL epinephrine. All subjects had axial T2-weighted and fat-suppressed images at 0, 60, and 120 minutes after injection. The localization, area, and intensity (signal characteristics) of the solutions were analyzed and onset and duration times of the anesthesia were recorded. There were no significant differences between groups with regard to the intensity and area of the solutions at 0, 60, and 120 minutes after injection, but differences were found within each group. No between-group differences were found on magnetic resonance imaging in the distribution and absorption of lidocaine with or without epinephrine and articaine with 0.006 and 0.012 mg/mL epinephrine. All solutions were noticeably absorbed at 120 minutes after injection. Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  11. Imaging Plasmon Hybridization of Fano Resonances via Hot-Electron-Mediated Absorption Mapping.

    Science.gov (United States)

    Simoncelli, Sabrina; Li, Yi; Cortés, Emiliano; Maier, Stefan A

    2018-05-04

    The inhibition of radiative losses in dark plasmon modes allows storing electromagnetic energy more efficiently than in far-field excitable bright-plasmon modes. As such, processes benefiting from the enhanced absorption of light in plasmonic materials could also take profit of dark plasmon modes to boost and control nanoscale energy collection, storage, and transfer. We experimentally probe this process by imaging with nanoscale precision the hot-electron driven desorption of thiolated molecules from the surface of gold Fano nanostructures, investigating the effect of wavelength and polarization of the incident light. Spatially resolved absorption maps allow us to show the contribution of each element of the nanoantenna in the hot-electron driven process and their interplay in exciting a dark plasmon mode. Plasmon-mode engineering allows control of nanoscale reactivity and offers a route to further enhance and manipulate hot-electron driven chemical reactions and energy-conversion and transfer at the nanoscale.

  12. Sensitivity of 238U resonance absorption to library multigroup structure as calculated by WIMS-AECL

    International Nuclear Information System (INIS)

    Laughton, P.J.; Donnelly, J.V.

    1995-01-01

    In simulations of the TRX-1 experimental lattice, WIMS-AECL overpredicts, relative to MCNP, resonance absorption in neutron-energy groups containing the three large, low-lying resonances of 238 U when a standard ENDF/B-V-based library is used. A total excess in these groups of 4.0 neutron captures by 238 U per thousand fission neutrons has been observed. Similar comparisons are made in this work for the MIT-4 experimental lattice and simplified CANDU lattice cells containing 37-element fuel, with and without heavy-water coolant. Eleven different 89-group cross-section libraries were constructed for WIMS-AECL from ENDF/B-V data: only the neutron-energy-group boundaries used in generating multigroup cross sections and the Goldstein-Cohen correction factors differ from one library to the next. The first library uses the original 89-group structure, and the other ten involve energy groups of varying widths centred on the three large, low-lying resonances of 238 U. For TRX-1, some reduction in total discrepancy in 238 U capture can be achieved by using a new structure, although the improvement is small. The discrepancies in 238 U capture are of the same order for the MIT-4 case as those observed for TRX-1 for both the original group structure and the ten new structures. The WIMS-AECL calculation of 238 U resonance absorption in the same ranges of energy for the simplified CANDU 37-element lattice are in better agreement with MCNP than they are for TRX-1 and MIT-4: when the original structure is used, WIMS-AECL underpredicts total capture rate by 238 U in the energy range of interest by only 0.56 per thousand fission neutrons (coolant present) and 0.88 per thousand fission neutrons (voided coolant channel). The discrepancies are reduced when some of the new structures are used. For almost all of the cases considered here-TRX-1, MIT-4 and CANDU with coolant-better group-by-group agreement of 238 U capture around the 6.67-eV resonance is achieved by using a new library

  13. Resonant two-photon absorption and electromagnetically induced transparency in open ladder-type atomic system.

    Science.gov (United States)

    Moon, Han Seb; Noh, Heung-Ryoul

    2013-03-25

    We have experimentally and theoretically studied resonant two-photon absorption (TPA) and electromagnetically induced transparency (EIT) in the open ladder-type atomic system of the 5S(1/2) (F = 1)-5P(3/2) (F' = 0, 1, 2)-5D(5/2) (F″ = 1, 2, 3) transitions in (87)Rb atoms. As the coupling laser intensity was increased, the resonant TPA was transformed to EIT for the 5S(1/2) (F = 1)-5P(3/2) (F' = 2)-5D(5/2) (F″ = 3) transition. The transformation of resonant TPA into EIT was numerically calculated for various coupling laser intensities, considering all the degenerate magnetic sublevels of the 5S(1/2)-5P(3/2)-5D(5/2) transition. From the numerical results, the crossover from TPA to EIT could be understood by the decomposition of the spectrum into an EIT component owing to the pure two-photon coherence and a TPA component caused by the mixed term.

  14. Experimental test of resonant absorption theory. Final report, January 1, 1978-December 31, 1979

    International Nuclear Information System (INIS)

    Yablonovitch, E.

    1979-05-01

    This experimental research has probed the nature of resonant absorption (RA) of laser light by laser-produced plasmas. The plasmas were created by optical breakdown of a shockfront produced in an electrothermal shock tube. This procedure allows the density structure of the plasma, and in particular, the orientation of the plasma critical-density surface, to be reproducibly formed from one shot to the next. Thus, for the first time, RA has been controllably and reproducibly studied in isolation from other plasma physics. The angular distribution of fast electrons emitted by RA and wavebreaking has been studied, and it is observed that the emission is directed in a narrow cone centered on the shockfront density-gradient vector, in agreement with the theory of wavebreaking

  15. Measurement of specific heat and specific absorption rate by nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Gultekin, David H., E-mail: david.gultekin@aya.yale.edu [Department of Electrical Engineering, Yale University, New Haven, CT 06520 (United States); Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065 (United States); Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065 (United States); Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232 (United States); Gore, John C. [Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232 (United States); Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37232 (United States); Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232 (United States); Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37232 (United States); Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232 (United States)

    2010-05-20

    We evaluate a nuclear magnetic resonance (NMR) method of calorimetry for the measurement of specific heat (c{sub p}) and specific absorption rate (SAR) in liquids. The feasibility of NMR calorimetry is demonstrated by experimental measurements of water, ethylene glycol and glycerol using any of three different NMR parameters (chemical shift, spin-spin relaxation rate and equilibrium nuclear magnetization). The method involves heating the sample using a continuous wave laser beam and measuring the temporal variation of the spatially averaged NMR parameter by non-invasive means. The temporal variation of the spatially averaged NMR parameter as a function of thermal power yields the ratio of the heat capacity to the respective nuclear thermal coefficient, from which the specific heat can be determined for the substance. The specific absorption rate is obtained by subjecting the liquid to heating by two types of radiation, radiofrequency (RF) and near-infrared (NIR), and by measuring the change in the nuclear spin phase shift by a gradient echo imaging sequence. These studies suggest NMR may be a useful tool for measurements of the thermal properties of liquids.

  16. Intermolecular interaction of photoexcited Cu(/TMpy-P4) with water studied by transient resonance Raman and picosecond absorption spectroscopies

    NARCIS (Netherlands)

    Kruglik, S.; Kruglik, Sergei G.; Ermolenkov, Vladimir V.; Shvedko, Alexander G.; Orlovich, Valentine A.; Galievsky, Victor A.; Chirvony, Vladimir S.; Otto, Cornelis; Turpin, Pierre-Yves

    1997-01-01

    photoinduced complex between Cu(TMpy-P4) and water molecules, reversibly axially coordinated to the central metal, was observed in picosecond transient absorption and nanosecond resonance Raman experiments. This complex is rapidly created (τ1 = 15 ± 5 ps) in the excited triplet (π, π*) state of

  17. Resonant absorption in semiconductor nanowires and nanowire arrays: Relating leaky waveguide modes to Bloch photonic crystal modes

    Energy Technology Data Exchange (ETDEWEB)

    Fountaine, Katherine T., E-mail: kfountai@caltech.edu [Department of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Whitney, William S. [Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Department of Physics, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Atwater, Harry A. [Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States); Department of Applied Physics and Materials Science, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125 (United States)

    2014-10-21

    We present a unified framework for resonant absorption in periodic arrays of high index semiconductor nanowires that combines a leaky waveguide theory perspective and that of photonic crystals supporting Bloch modes, as array density transitions from sparse to dense. Full dispersion relations are calculated for each mode at varying illumination angles using the eigenvalue equation for leaky waveguide modes of an infinite dielectric cylinder. The dispersion relations along with symmetry arguments explain the selectivity of mode excitation and spectral red-shifting of absorption for illumination parallel to the nanowire axis in comparison to perpendicular illumination. Analysis of photonic crystal band dispersion for varying array density illustrates that the modes responsible for resonant nanowire absorption emerge from the leaky waveguide modes.

  18. Direct observation of effective temperature of Ta atom in layer compound TaS2 by neutron resonance absorption spectrometer

    International Nuclear Information System (INIS)

    Tokuda, Koji; Kamiyama, Takashi; Kiyanagi, Yoshiaki; Moreh, R.; Ikeda, Susumu

    2001-01-01

    A neutron resonance absorption spectrometer, DOG has been installed at KENS, High Energy Accelerator Research Organization Neutron Source, which enables us to investigate the motions of a particular element by analyzing the line width of resonance absorption spectrum. We measured the temperature dependence of the effective temperature of Ta motion in TaS 2 as well as in Ta metal using DOG. The effective temperatures extracted from the observed absorption spectrum agree well with the calculated values from the phonon density of states of Ta metal over a wide temperature range of 10 to 300 K. We also succeeded in measuring both the angular dependence and the temperature dependence of effective temperatures of Ta in a layer compound TaS 2 . Based on the temperature dependence of the effective temperature, the partial phonon density of states of Ta in TaS 2 was discussed. (author)

  19. Two-ion hybrid resonances and ion cyclotron absorption in tokamak plasmas

    International Nuclear Information System (INIS)

    Brambilla, M.; Ottaviani, M.

    1983-11-01

    The behaviour of IC waves near resonances in tokamak geometry is investigated in details. For this purpose, a one-dimensional model is proposed, which takes into account the orientation of the incident wavefronts with respect both to the singular layer and to the magnetic surfaces. The differential equations describing the waves are derived again from Vlasov-Maxwell equations in the finite Larmor radius approximation; they are shown to conserve the wave power flux in the absence of dissipation, and to reproduce the local dispersion relation in the WKB limit. These equations are solved exactly in some important situations, and with the Green-function technique in the general case. The amount of power coupled to Bernstein waves and absorbed by cyclotron damping is explicitly evaluated. (orig.)

  20. Coronal heating by the resonant absorption of Alfven waves - Importance of the global mode and scaling laws

    Science.gov (United States)

    Steinolfson, Richard S.; Davila, Joseph M.

    1993-01-01

    Numerical simulations of the MHD equations for a fully compressible, low-beta, resistive plasma are used to study the resonance absorption process for the heating of coronal active region loops. Comparisons with more approximate analytic models show that the major predictions of the analytic theories are, to a large extent, confirmed by the numerical computations. The simulations demonstrate that the dissipation occurs primarily in a thin resonance layer. Some of the analytically predicted features verified by the simulations are (a) the position of the resonance layer within the initial inhomogeneity; (b) the importance of the global mode for a large range of loop densities; (c) the dependence of the resonance layer thickness and the steady-state heating rate on the dissipation coefficient; and (d) the time required for the resonance layer to form. In contrast with some previous analytic and simulation results, the time for the loop to reach a steady state is found to be the phase-mixing time rather than a dissipation time. This disagreement is shown to result from neglect of the existence of the global mode in some of the earlier analyses. The resonant absorption process is also shown to behave similar to a classical driven harmonic oscillator.

  1. Electronic decay cascades in media initiated by resonant absorption of X-ray photons

    Energy Technology Data Exchange (ETDEWEB)

    Miteva, Tsveta

    2015-07-16

    The resonant-Auger - interatomic Coulombic decay (RA-ICD) cascade was recently proposed as a very efficient means of controlling the generation site and energies of slow ICD electrons. The control mechanism was verified in a series of experiments where both the energy of the photons producing the initial core excitation, and the neighbouring species were varied. The aim of this thesis is to provide a detailed theoretical investigation of the RA-ICD cascade in rare-gas dimers and give a first insight into the course of the cascade in aqueous medium. The potential energy curves (PECs) of ionisation satellites are key ingredients in the theoretical description of electronic decay cascades. In the first chapter, we conducted a study on the PECs of the ionisation satellites of the ArHe dimer with a view to modelling such PECs in heavier dimers. Our results show that the complex valence structure in the rare-gas atom leads to the mixing of different electronic configurations of the dimer, which prevents one from assigning a single dicationic parent state to some of the ionisation satellites. In the second part of the thesis, we present and analyse the ICD-electron and kinetic-energy-release (KER) spectra following different resonant core excitations of Ar in the rare-gas dimers Ar{sub 2} and ArKr. We demonstrate that the manifold of ICD states populated in the resonant Auger process consists of fast- and slow-decaying ionisation satellites, and that the accurate description of nuclear dynamics in the latter ICD states is crucial for obtaining theoretical electron and KER spectra in good agreement with the experiment. We also show that by varying the neighbouring atom one can tune the energies of the emitted ICD electrons and even control the ICD yield. Finally, as a first step towards the investigation of the RA-ICD cascade in aqueous medium, we present and discuss the X-Ray absorption spectra of microsolvated clusters of Na{sup +} and Mg{sup 2+} at the metal 1s

  2. Optical resonance-enhanced absorption-based near-field immunochip biosensor for allergen detection.

    Science.gov (United States)

    Maier, Irene; Morgan, Michael R A; Lindner, Wolfgang; Pittner, Fritz

    2008-04-15

    An optical immunochip biosensor has been developed as a rapid method for allergen detection in complex food matrixes, and its application evaluated for the detection of the egg white allergens, ovalbumin and ovomucoid. The optical near-field phenomenon underlying the basic principle of the sensor design is called resonance-enhanced absorption (REA), which utilizes gold nanoparticles (Au NPs) as signal transducers in a highly sensitive interferometric setup. Using this approach, a novel, simple, and rapid colorimetric solid-phase immunoassay on a planar chip substrate was realized in direct and sandwich assay formats, with a detection system that does not require any instrumentation for readout. Semiquantitative immunochemical responses are directly visible to the naked eye of the analyst. The biosensor shows concentration-dependent color development by capturing antibody-functionalized Au NPs on allergen-coated chips and has a detection limit of 1 ng/mL. To establish a rapid method, we took advantage of the physicochemical microenvironment of the Au NP-antibody bioconjugate to be bound directly over an interacting poly(styrene-methyl methacrylate) interlayer by an immobilized antigen. In the direct assay format, a coating time with allergen of only 5 min under "soft" nondenaturing conditions was sufficient for accurate reproducibility and sensitivity. In conclusion, the REA-based immunochip sensor is easy to fabricate, is reproducible and selective in its performance, has minimal technical requirements, and will enable high-throughput screening of affinity binding interactions in technological and medical applications.

  3. The effects of proton-beam quality on the production of gamma rays for nuclear resonance absorption in nitrogen

    International Nuclear Information System (INIS)

    Graybill, R.; Morgado, R.E.; Cappiello, C.C.

    1994-05-01

    The authors describe a method for performing nuclear-resonance absorption with the proton beam from a radio-frequency quadrupole (RFQ) linear accelerator. The objective was to assess the suitability of the pulsed beam from an RFQ to image nitrogen compared to electrostatic accelerators. This choice of accelerator results in trade-offs in performance and complexity, in return for the prospect of higher average current. In spite of a reduced resonance attenuation coefficient in nitrogen, they successfully produced three-dimensional tomographic images of real explosives in luggage the first time the unoptimized system was operated. The results and assessments of the initial laboratory measurements are reported

  4. The effects of proton-beam quality on the production of gamma rays for nuclear resonance absorption in nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Graybill, R. [ed.; Morgado, R.E.; Cappiello, C.C. [and others

    1994-05-01

    The authors describe a method for performing nuclear-resonance absorption with the proton beam from a radio-frequency quadrupole (RFQ) linear accelerator. The objective was to assess the suitability of the pulsed beam from an RFQ to image nitrogen compared to electrostatic accelerators. This choice of accelerator results in trade-offs in performance and complexity, in return for the prospect of higher average current. In spite of a reduced resonance attenuation coefficient in nitrogen, they successfully produced three-dimensional tomographic images of real explosives in luggage the first time the unoptimized system was operated. The results and assessments of the initial laboratory measurements are reported.

  5. Effect of endorsed body weight on specific absorption rate during magnetic resonance imaging

    International Nuclear Information System (INIS)

    Singh, Harish K.; Gupta, R.K.; Gujral, R.B.; Shukla, A.K.

    2001-01-01

    As a routine safety of the patients undergoing magnetic resonance imaging (MRI), the limits of radiofrequency (RF) specific absorption rate (SAR) are set by the manufacturers of all MRI systems because RF causes thermo genesis of the RF exposed tissue. It has been mandatory practice to endorse body weight and age of the patients required by the MRI systems for the SAR check. The problems arise on those patients who are critically ill, and consequently body weight could not be measured. In such cases, approximate body weight has to be endorsed. In case of underweight and overweight patients, sometimes SAR check does not permit to run the MRI pulse sequences. Also, in such cases, body weight remains the parameter which is being changed to get the MRI done. The purpose of this study is to assess the change of SAR with endorsed body weight. The change of SAR was recorded with the endorsed weight using phantoms and most commonly used T1 and T2 weighted pulse sequence on clinical MRI system. At true endorsed weight, using respective coils and the head and spine coil phantoms, the body averaged and localised SAR were found to be within limits while this was not the case with body coil phantom. Unrealistic endorsed weights are permissible for the adult age cases in all coils while using the routine T1 and T2 weighted pulse sequences. This finding is absolutely new in the field and certainly, will be of great applicability to develop a uniform and standard system of SAR checks in the patient interest. (author)

  6. Resonant metallic nanostructure for enhanced two-photon absorption in a thin GaAs p-i-n diode

    Energy Technology Data Exchange (ETDEWEB)

    Portier, Benjamin; Pardo, Fabrice; Péré-Laperne, Nicolas; Steveler, Emilie; Dupuis, Christophe; Bardou, Nathalie; Lemaître, Aristide; Pelouard, Jean-Luc, E-mail: jean-luc.pelouard@lpn.cnrs.fr [Laboratoire de Photonique et de Nanostructures (LPN-CNRS), Route de Nozay, 91460 Marcoussis (France); Vest, Benjamin; Jaeck, Julien; Rosencher, Emmanuel [ONERA The French Aerospace Lab, Chemin de la Hunière, F-91760 Palaiseau (France); Haïdar, Riad [ONERA The French Aerospace Lab, Chemin de la Hunière, F-91760 Palaiseau (France); École Polytechnique, Département de Physique, F-91128 Palaiseau (France)

    2014-07-07

    Degenerate two-photon absorption (TPA) is investigated in a 186 nm thick gallium arsenide (GaAs) p-i-n diode embedded in a resonant metallic nanostructure. The full device consists in the GaAs layer, a gold subwavelength grating on the illuminated side, and a gold mirror on the opposite side. For TM-polarized light, the structure exhibits a resonance close to 1.47 μm, with a confined electric field in the intrinsic region, far from the metallic interfaces. A 109 times increase in photocurrent compared to a non-resonant device is obtained experimentally, while numerical simulations suggest that both gain in TPA-photocurrent and angular dependence can be further improved. For optimized grating parameters, a maximum gain of 241 is demonstrated numerically and over incidence angle range of (−30°; +30°).

  7. Resonant metallic nanostructure for enhanced two-photon absorption in a thin GaAs p-i-n diode

    International Nuclear Information System (INIS)

    Portier, Benjamin; Pardo, Fabrice; Péré-Laperne, Nicolas; Steveler, Emilie; Dupuis, Christophe; Bardou, Nathalie; Lemaître, Aristide; Pelouard, Jean-Luc; Vest, Benjamin; Jaeck, Julien; Rosencher, Emmanuel; Haïdar, Riad

    2014-01-01

    Degenerate two-photon absorption (TPA) is investigated in a 186 nm thick gallium arsenide (GaAs) p-i-n diode embedded in a resonant metallic nanostructure. The full device consists in the GaAs layer, a gold subwavelength grating on the illuminated side, and a gold mirror on the opposite side. For TM-polarized light, the structure exhibits a resonance close to 1.47 μm, with a confined electric field in the intrinsic region, far from the metallic interfaces. A 109 times increase in photocurrent compared to a non-resonant device is obtained experimentally, while numerical simulations suggest that both gain in TPA-photocurrent and angular dependence can be further improved. For optimized grating parameters, a maximum gain of 241 is demonstrated numerically and over incidence angle range of (−30°; +30°).

  8. Ions extraction and collection using the RF resonance method and taking into consideration the sputtering loss

    International Nuclear Information System (INIS)

    Xie Guofeng; Wang Dewu; Ying Chuntong

    2005-01-01

    One-dimensional ions extraction and collection using the RF resonance method is studied by PIC-MCC simulation. The energy and angle distribution of extracted ions is recorded and the sputtering loss is calculated. The results show that compared with parallel electrode method, RF resonance method has advantages such as shorter extraction time, lower collision loss and sputtering loss and higher collection ratio; the extraction time and collision loss are decreased with increasing extraction voltage, but the sputtering loss increases and collection ratio decreases; collision loss is decreased with increasing magnetic field, but the sputtering loss increases and collection ratio decreases. (authors)

  9. Resonance absorption of nuclear gamma radiation; Absorption par resonance des rayons gamma; Rezonansnaya absorbtsiya i rasseyanie yadernogo gamma-izlucheniya; Absorcion por resonancia de las radiaciones gamma en los nucleos

    Energy Technology Data Exchange (ETDEWEB)

    Hanna, S S; Perlow, G J [Argonne National Laboratory, Argonne, IL (United States)

    1962-01-15

    Recoilless emission and absorption of nuclear radiation, as demonstrated by Moessbauer, provides a simple means of studying the interaction of nuclei with electromagnetic radiation and, of greater importance, provides an extremely sensitive tool for the investigation of a large number of physical problems. A very favourable situation arises with the Fe{sup 57} nucleus where resonance absorption may be used as a very sensitive detector of the frequency change of electromagnetic radiation. Resonance absorption in Fe57 has been studied in detail. The strength of the absorption, the line shape, and line shift have all been observed as a function of temperature. The polarization of the radiation has been examined by means of experiments with magnetized sources and absorbers. The hyperfine spectrum of the resonance radiation has been analysed with and without polarization. These studies have led to an interpretation of the hyperfine structure in terms of the properties of the nuclear states and the hyperfine interaction in iron. The effect of an external magnetic field on the hyperfine structure has also been investigated. The resonance absorption in Fe{sup 57} has been used to study the connexion between the time development of the decay of a nuclear state and the spectrum of the observed radiation. Detailed observations are made of the time spectrum of filtered resonance radiation for a variety of conditions. (author) [French] L'emission et l'absorption de rayonnements nucleaires sans recul, phenomenes mis en evidence par Mossbauer, offrent un moyen simple d'etudier l'interaction des noyaux et des rayonnements electromagnetiques et, ce qui est plus important encore, fournissent un instrument extremement sensible pour l'etude d'un grand nombre de problemes de physique. Une situation tres favorable se presente dans le cas du noyau de {sup 57}Fe, ou l'on peut utiliser l'absorption par resonance comme un detecteur tres sensible des changements de frequence des rayonnements

  10. Experimental observation of microwave absorption and electron heating due to the two plasmon decay instability and resonance absorption

    International Nuclear Information System (INIS)

    Rasmussen, D.A.

    1981-01-01

    The interaction of intense microwaves with an inhomogeneous plasma is studied in two experimental devices. In the first device an investigation was made of microwave absorption and electron heating due to the parametric decay of microwaves into electron plasma waves (Two Plasmon Decay instability, TPDI), modeling a process which can occur near the quarter critical surface in laser driven pellets. P-polarized microwave (f = 1.2 GHz, P 0 less than or equal to 12 kW) are applied to an essentially collisionless, inhomogeneous plasma, in an oversized waveguide, in the U.C. Davis Prometheus III device. The initial density scale length near the quarter critical surface is quite long (L/lambda/sub De/ approx. = 3000 or k 0 L approx. = 15). The observed threshold power for the TPDI is quite low (P/sub T/approx. = 0.1 kW or v/sub os//v/sub e/ approx. = 0.1). Near the threshold the decay waves only occur near the quarter critical surface. As the incident power is increased above threshold, the decay waves spread to lower densities, and for P 0 greater than or equal to lkW, (v/sub os//v/sub e/ greater than or equal to 0.3) suprathermal electron heating is strong for high powers (T/sub H/ less than or equal to 12 T/sub e/ for P 0 less than or equal to 8 kW or v/sub os//v/sub e/ less than or equal to 0.9)

  11. The applicability of detailed process for neutron resonance absorption to neutronics analyses in LWR next generation fuels to extend burnup

    International Nuclear Information System (INIS)

    Kameyama, Takanori; Nauchi, Yasushi

    2004-01-01

    Neutronics analyses with detail processing for neutron resonance absorption in LWR next generation UOX and MOX fuels to extend burnup were performed based on the neutronic transport and burnup calculation. In the detailed processing, ultra-fine energy nuclear library and collision probabilities between neutron and U, Pu nuclides (actinide nuclides) are utilized for two-dimension geometry. In the usual simple processing (narrow resonance approximation), shielding factors and compensation equations for neutron resonance absorption are utilized. The results with detailed and simple processing were compared to clarify where the detailed processing is needed. The two processing caused difference of neutron multiplication factor by 0.5% at the beginning of irradiation, while the difference became smaller as burnup increased and was not significant at high burnup. The nuclide compositions of the fuel rods for main actinide nuclides were little different besides Cm isotopes by the processing, since the neutron absorption rate of 244 Cm became different. The detail processing is needed to evaluate the neutron emission rate in spent fuels. In the fuel assemblies, the distributions of rod power rates were not different within 0.5%, and the peak rates of fuel rod were almost the same by the two processing at the beginning of irradiation when the peak rate is the largest during the irradiation. The simple processing is also satisfied for safety evaluation based on the peak rate of rod power. The difference of local power densities in fuel pellets became larger as burnup increased, since the neutron absorption rate of 238 U in the peripheral region of pellets were significantly different by the two processing. The detail processing is needed to evaluate the fuel behavior at high burnup. (author)

  12. Anomalies in resonant absorption line profiles of atoms with large hyperfine splitting

    International Nuclear Information System (INIS)

    Parkhomenko, A.I.; Pod'yachev, S.P.; Privalov, T.I.; Shalagin, A.M.

    1997-01-01

    We examine a monochromatic absorption line in the velocity-nonselective excitation of atoms when the components of the hyperfine stricture of the electronic ground states are optically pumped. We show that the absorption lines possess unusual substructures for some values of the hyperfine splitting of the ground state (which exceed the Doppler absorption linewidth severalfold). These substructures in the absorption spectrum are most apparent if the hyperfine structure of the excited electronic state is taken into account. We calculate the absorption spectra of monochromatic light near the D 1 and D 2 lines of atomic rubidium 85,87 Rb. With real hyperfine splitting taken into account, the D 1 and D 2 lines are modeled by 4- and 6-level diagrams, respectively. Finally, we show that atomic rubidium vapor can be successfully used to observe the spectral features experimentally

  13. Electron spin resonance insight into broadband absorption of the Cu3Bi(SeO32O2Br metamagnet

    Directory of Open Access Journals (Sweden)

    A. Zorko

    2016-05-01

    Full Text Available Metamagnets, which exhibit a transition from a low-magnetization to a high-magnetization state induced by the applied magnetic field, have recently been highlighted as promising materials for controllable broadband absorption. Here we show results of a multifrequency electron spin resonance (ESR investigation of the Cu3Bi(SeO32O2Br planar metamagnet on the kagome lattice. Its mixed antiferromagnetic/ferromagnetic phase is stabilized in a finite range of applied fields around 0.8 T at low temperatures and is characterized by enhanced microwave absorption. The absorption signal is non-resonant and its boundaries correspond to two critical fields that determine the mixed phase. With decreasing temperature these increase like the sublattice magnetization of the antiferromagnetic phase and show no frequency dependence between 100 and 480 GHz. On the contrary, we find that the critical fields depend on the magnetic-field sweeping direction. In particular, the higher critical field, which corresponds to the transition from the mixed to the ferromagnetic phase, shows a pronounced hysteresis effect, while such a hysteresis is absent for the lower critical field. The observed hysteresis is enhanced at lower temperatures, which suggests that thermal fluctuations play an important role in destabilizing the highly absorbing mixed phase.

  14. Device and method for luminescence enhancement by resonant energy transfer from an absorptive thin film

    Science.gov (United States)

    Akselrod, Gleb M.; Bawendi, Moungi G.; Bulovic, Vladimir; Tischler, Jonathan R.; Tisdale, William A.; Walker, Brian J.

    2017-12-12

    Disclosed are a device and a method for the design and fabrication of the device for enhancing the brightness of luminescent molecules, nanostructures, and thin films. The device includes a mirror, a dielectric medium or spacer, an absorptive layer, and a luminescent layer. The absorptive layer is a continuous thin film of a strongly absorbing organic or inorganic material. The luminescent layer may be a continuous luminescent thin film or an arrangement of isolated luminescent species, e.g., organic or metal-organic dye molecules, semiconductor quantum dots, or other semiconductor nanostructures, supported on top of the absorptive layer.

  15. Resonance absorption spectroscopy for laser-ablated lanthanide atom. (1) Optimized experimental conditions for isotope-selective absorption of gadolinium (Contract research)

    International Nuclear Information System (INIS)

    Miyabe, Masabumi; Oba, Masaki; Iimura, Hideki; Akaoka, Katsuaki; Maruyama, Yoichiro; Wakaida, Ikuo; Watanabe, Kazuo

    2008-06-01

    For remote isotope analysis of low-decontaminated TRU fuel, we are developing an analytical technique on the basis of the resonance absorption spectroscopy for the laser-ablation plume. To improve isotopic selectivity and detection sensitivity of this technique, we measured absorption spectra of Gd atom with various plume production conditions (ablation laser intensity, ambient gas and its pressure) and observation conditions (transition, probe height from sample, observation timing). As a result, high resolution spectrum was obtained from the observation of slow component of the plume produced under low-pressure rare-gas ambient. The observed narrowest linewidth of about 0.85GHz was found to be close to the Doppler width estimated for Gd atom of room temperature. Furthermore, relaxation rate of higher meta-stable state was found to be higher than that of ground state, suggesting that use of the transition arising from ground state or lower meta-stable state is preferable for highly sensitive isotope analysis. (author)

  16. Electron paramagnetic resonance and optical absorption of uranium ions diluted in CdF2 single crystals

    International Nuclear Information System (INIS)

    Pereira, J.J.C.R.

    1976-08-01

    The electron paramagnetic resonance (EPR) has been studied in conection with the optical absortion spectra of Uranium ions diluted in CdF 2 single crystals. Analyses of the EPR and optical absorption spectra obtained experimentally, and a comparison with known results in the isomorfic CaF 2 , SrF 2 and BaF 2 , allowed the identification of two paramagnetic centers associated with Uranium ions. These are the U(2+) ion in cubic symmetry having the triplet γ 5 as ground state, and the U(3+) ion in cubic symmetry having the dublet γ 6 as ground state. (Author) [pt

  17. Visual and Plasmon Resonance Absorption Sensor for Adenosine Triphosphate Based on the High Affinity between Phosphate and Zr(IV)

    OpenAIRE

    Qi, Wenjing; Liu, Zhongyuan; Zhang, Wei; Halawa, Mohamed Ibrahim; Xu, Guobao

    2016-01-01

    Zr(IV) can form phosphate and Zr(IV) (?PO3 2??Zr4+?) complex owing to the high affinity between Zr(IV) with phosphate. Zr(IV) can induce the aggregation of gold nanoparticles (AuNPs), while adenosine triphosphate(ATP) can prevent Zr(IV)-induced aggregation of AuNPs. Herein, a visual and plasmon resonance absorption (PRA)sensor for ATP have been developed using AuNPs based on the high affinity between Zr(IV)with ATP. AuNPs get aggregated in the presence of certain concentrations of Zr(IV). Aft...

  18. Second and third peaks in the non-resonant microwave absorption spectra of superconducting Bi2212 crystals

    CSIR Research Space (South Africa)

    Srinivasu, V V

    2010-04-01

    Full Text Available . Bhat, S.V., Ganguly, P., Ramakrishnan, T.V., Rao, C.N.R.: J. Phys. C 20, L559 (1987) 2. Blazey, K.W., Muller, K.A., Bednorz, J.G., Berlinger, W., Amoretti, G., Buluggiu, E., Vera, A., Matacotta, F.C.: Phys. Rev. B 36, 7241 (1987) 3. Kachaturyan, K... 10.1007/s10948-009-0530-5 O R I G I NA L PA P E R Second and Third Peaks in the Non-resonant Microwave Absorption Spectra of Superconducting Bi2212 Crystals V.V. Srinivasu Received: 19 August 2009 / Accepted: 25 August 2009 ' Springer Science...

  19. Hyperfine structure of 147,149Sm measured using saturated absorption spectroscopy in combination with resonance-ionization mass spectroscopy

    International Nuclear Information System (INIS)

    Park, Hyunmin; Lee, Miran; Rhee, Yongjoo

    2003-01-01

    The hyperfine structures of four levels of the Sm isotopes have been measured by means of diode-laser-based Doppler-free saturated absorption spectroscopy in combination with a diode-laser-initiated resonance-ionization mass spectroscopy. It was demonstrated that combining the two spectroscopic methods was very effective for the identification and accurate measurement of the spectral lines of atoms with several isotopes, such as the rare-earth elements. From the obtained spectra, the hyperfine constants A and B for the odd-mass isotopes 147 Sm and 149 Sm were determined for four upper levels of the studied transitions.

  20. Selective Two-Photon Absorptive Resonance Femtosecond-Laser Electronic-Excitation Tagging (STARFLEET) Velocimetry in Flow and Combustion Diagnostics

    Science.gov (United States)

    Jiang, Naibo; Halls, Benjamin R.; Stauffer, Hans U.; Roy, Sukesh; Danehy, Paul M.; Gord, James R.

    2016-01-01

    Selective Two-Photon Absorptive Resonance Femtosecond-Laser Electronic-Excitation Tagging (STARFLEET), a non-seeded ultrafast-laser-based velocimetry technique, is demonstrated in reactive and non-reactive flows. STARFLEET is pumped via a two-photon resonance in N2 using 202.25-nm 100-fs light. STARFLEET greatly reduces the per-pulse energy required (30 µJ/pulse) to generate the signature FLEET emission compared to the conventional FLEET technique (1.1 mJ/pulse). This reduction in laser energy results in less energy deposited in the flow, which allows for reduced flow perturbations (reactive and non-reactive), increased thermometric accuracy, and less severe damage to materials. Velocity measurements conducted in a free jet of N2 and in a premixed flame show good agreement with theoretical velocities and further demonstrate the significantly less-intrusive nature of STARFLEET.

  1. Resonant photoemission of La and Yb at the 3d absorption edge

    CERN Document Server

    Lagarde, P; Ogasawara, H; Kotani, A

    2003-01-01

    Resonant photoemission and resonant Auger experiments at the 3d threshold are presented for La and Yb over a binding energy domain which extends up to the 4p levels. These experimental results are well explained by calculations in the framework of full-multiplet Hartree-Fock theory with an atomic model. Strong participator and spectator Auger transitions are observed without ordinary Auger transition, indicating that the 4f wavefunction is well localized in the intermediate state even in the case of La. The 4d sub 3 sub / sub 2 and 4d sub 5 sub / sub 2 branching ratio of the 4d resonant photoemission of La at the M sub 4 and M sub 5 edges is observed experimentally and analyzed theoretically. The difference in the resonant processes behavior for La and Yb is discussed based upon the different 4f occupation number.

  2. Power Take-Off with Integrated Resonator for Energy Extraction from Linear Motions

    DEFF Research Database (Denmark)

    2014-01-01

    The invention relates to a magnetic gear for converting linear motion into rotational motion and vice versa. The present invention converts slow linear irregular oscillating motion of wave energy devices into torque on a high speed shaft for powering a generator while making the wave energy device...... of sea or ocean waves into useful energy, such as electricity. The invention relates to the control and operation of a magnetic gear based motor/generator system. The invention provides a high force density electric powered linear actuator....... resonate with the waves. The invention relates to the field of energy-harvesting from energy sources, where the energy-harvesting requires the extraction of energy from slow and often irregular reciprocating motion of bodies. The present invention relates to a wave power apparatus for converting power...

  3. Double resonance capacitance spectroscopy (DORCAS): A new experimental technique for assignment of X-ray absorption peaks to surface sites of semiconductor

    CERN Document Server

    Ishii, M

    2003-01-01

    As a new microspectroscopy for semiconductor surface analysis using an X-ray beam, double resonance capacitance spectroscopy (DORCAS) is proposed. For a microscopic X-ray absorption measurement, a local capacitance change owing to X-ray induced emission of localized electrons is detected by a microprobe. The applied bias voltage V sub b dependence of the capacitance also provides information on the surface density of state. The resonance of the Fermi energy with a surface level by V sub b control makes possible the selection of the observable surface site in the X-ray absorption measurements, i.e. site-specific spectroscopy. The double resonance of the surface site selection (V sub b resonance) and the resonant X-ray absorption of the selected site (photon energy h nu resonance) enhances the capacitance signal. The DORCAS measurement of the GaAs surface shows correlation peaks at h nu=10.402 keV and V sub b =-0.4 V and h nu=10.429 keV and V sub b =+0.1 V, indicating that these resonant X-ray absorption peaks ...

  4. Using resonance light scattering and UV/vis absorption spectroscopy to study the interaction between gliclazide and bovine serum albumin.

    Science.gov (United States)

    Zhang, Qiu-Ju; Liu, Bao-Sheng; Li, Gai-Xia; Han, Rong

    2016-08-01

    At different temperatures (298, 310 and 318 K), the interaction between gliclazide and bovine serum albumin (BSA) was investigated using fluorescence quenching spectroscopy, resonance light scattering spectroscopy and UV/vis absorption spectroscopy. The first method studied changes in the fluorescence of BSA on addition of gliclazide, and the latter two methods studied the spectral change in gliclazide while BSA was being added. The results indicated that the quenching mechanism between BSA and gliclazide was static. The binding constant (Ka ), number of binding sites (n), thermodynamic parameters, binding forces and Hill's coefficient were calculated at three temperatures. Values for the binding constant obtained using resonance light scattering and UV/vis absorption spectroscopy were much greater than those obtained from fluorescence quenching spectroscopy, indicating that methods monitoring gliclazide were more accurate and reasonable. In addition, the results suggest that other residues are involved in the reaction and the mode 'point to surface' existed in the interaction between BSA and gliclazide. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  5. Occupied and unoccupied electronic structures of an L-cysteine film studied by core-absorption and resonant photoelectron spectroscopies

    Science.gov (United States)

    Kamada, M.; Hideshima, T.; Azuma, J.; Yamamoto, I.; Imamura, M.; Takahashi, K.

    2016-04-01

    Unoccupied and occupied electronic structures of an L-cysteine film have been studied by absorption and resonant photoelectron spectroscopies. Core absorptions at S-L, C-K, N-K, and O-K levels indicate that the lower unoccupied states are predominantly composed of oxygen-2p, carbon-2p, and sulfur-4s+3d orbitals, while higher unoccupied states may be attributed dominantly to nitrogen-np (n ≥ 3), oxygen-np (n ≥ 3), and sulfur-ns+md (n ≥ 4, m ≥ 3) orbitals. Resonant photoelectron spectra at S-L23 and O-K levels indicate that the highest occupied state is originated from sulfur-3sp orbitals, while oxygen-2sp orbitals contribute to the deeper valence states. The delocalization lifetimes of the oxygen-1s and sulfur-2p excited states are estimated from a core-hole clock method to be about 9 ± 1 and 125 ± 25 fs, respectively.

  6. Occupied and unoccupied electronic structures of an L-cysteine film studied by core-absorption and resonant photoelectron spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Kamada, M., E-mail: kamada@cc.saga-u.ac.jp; Hideshima, T.; Azuma, J.; Yamamoto, I.; Imamura, M.; Takahashi, K. [Synchrotron Light Application Center, Saga University, Honjo 1, Saga 840-8502 (Japan)

    2016-04-15

    Unoccupied and occupied electronic structures of an L-cysteine film have been studied by absorption and resonant photoelectron spectroscopies. Core absorptions at S-L, C-K, N-K, and O-K levels indicate that the lower unoccupied states are predominantly composed of oxygen-2p, carbon-2p, and sulfur-4s+3d orbitals, while higher unoccupied states may be attributed dominantly to nitrogen-np (n ≥ 3), oxygen-np (n ≥ 3), and sulfur-ns+md (n ≥ 4,  m ≥ 3) orbitals. Resonant photoelectron spectra at S-L{sub 23} and O-K levels indicate that the highest occupied state is originated from sulfur-3sp orbitals, while oxygen-2sp orbitals contribute to the deeper valence states. The delocalization lifetimes of the oxygen-1s and sulfur-2p excited states are estimated from a core-hole clock method to be about 9 ± 1 and 125 ± 25 fs, respectively.

  7. New sub-Doppler absorption resonances in a thin gas cell produced by means of a running monochromatic wave

    International Nuclear Information System (INIS)

    Tajalli, H; Ahmadi, S; Izmailov, A Ch

    2002-01-01

    A theoretical investigation is carried out through the interaction of the plane running monochromatic light wave, having an arbitrary intensity, with atoms (molecules) of a rarefied gas in the plane cell (at the normal incidence of the wave). Cases of closed and open resonance transitions from the non-degenerate ground (or metastable) quantum level are considered. Possible sub-Doppler resonances are analysed in the wave absorption, caused by the transient establishment of the optical coherence on the transition, Rabi oscillations between its levels, and optical pumping during the free flights of particles between the walls of the cell. Results of the previous works on given problems are generalized, which were obtained at definite restrictions on the wave intensity and cell length. Moreover, non-trivial sub-Doppler spectral structures, resulting as a consequence of the dependence of the absorption saturation on the transit relaxation of particles, have been established and investigated. Such structures may consist of a number of peaks and dips caused by Rabi oscillations between the transition levels. The results obtained can be used in sub-Doppler spectroscopy and for the stabilization of laser frequencies in thin gas cells

  8. Enhanced absorption in Au nanoparticles/a-Si:H/c-Si heterojunction solar cells exploiting Au surface plasmon resonance

    Energy Technology Data Exchange (ETDEWEB)

    Losurdo, Maria; Giangregorio, Maria M.; Bianco, Giuseppe V.; Sacchetti, Alberto; Capezzuto, Pio; Bruno, Giovanni [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR, via Orabona 4, 70126 Bari (Italy)

    2009-10-15

    Au nanoparticles (NPs)/(n-type)a-Si:H/(p-type)c-Si heterojunctions have been deposited combining plasma-enhanced chemical-vapour deposition (PECVD) with Au sputtering. We demonstrate that a density of {proportional_to}1.3 x 10{sup 11} cm{sup -2} of Au nanoparticles with an approximately 20 nm diameter deposited onto (n-type)a-Si:H/(p-type)c-Si heterojunctions enhance performance exploiting the improved absorption of light by the surface plasmon resonance of Au NPs. In particular, Au NPs/(n-type)a-Si:H/(p-type)c-Si show an enhancement of 20% in the short-circuit current, J{sub SC}, 25% in the power output, P{sub max} and 3% in the fill factor, FF, compared to heterojunctions without Au NPs. Structures have been characterized by spectroscopic ellipsometry, atomic force microscopy and current-voltage (I-V) measurements to correlate the plasmon resonance-induced enhanced absorption of light with photovoltaic performance. (author)

  9. A generalization of the Livolant-Jeanpierre theory for resonance absorption calculation

    International Nuclear Information System (INIS)

    Reuss, P.

    1985-04-01

    Because of the large number of heavy nuclide resonances a detailed neutron flux calculation in the epithermal range cannot be made by standard nuclear reactor codes: it would need several tens of thousand of energy points. However, by using pre-calculated effective reaction rates only a few tens of groups are sufficient for accurate spectrum and reaction rate calculations, if a consistent formalism is used. Such a formalism was elaborated in the 1970s by M. Livolant and F. Jeanpierre (L.-J.) for the ''one resonant nuclide - one resonant zone'' problem, and was implemented in the APOLLO code. In practical cases there are several resonant nuclides and often resonant zones of different characteristics, e.g. a lattice constituted with different kinds of pins, a lattice with irregular ''water-holes'', a fuel element with temperature (therefore Doppler effect) gradients,... Since these problem cannot be correctly treated by APOLLO, a generalization of the formalism was derived. The basic principles were retained, and our aim was to construct an algorithm which would not require too expensive calculations. After a brief recall of the L.-J. theory, equations for the most general case are presented, some approximations for practical calculations proposed, and numerical tests on significant examples commented

  10. Optical absorption and electron spin resonance studies of Cu 2 in ...

    Indian Academy of Sciences (India)

    B2O3–As2O3 glasses. N Srinivasa Rao Shashidhar ... K Siva Kumar Syed Rahman. Ceramics and Glasses Volume 28 Issue 6 October 2005 pp 589-592 ... Keywords. Glass transition temperature; ESR; optical absorption; bonding parameters.

  11. Resonant photoelectron spectroscopy at the Mo 4p→4d absorption edge in MoS2

    International Nuclear Information System (INIS)

    Lince, J.R.; Didziulis, S.V.; Yarmoff, J.A.

    1991-01-01

    A systematic study has been conducted of the resonant behavior of the valence-band photoelectron spectrum of MoS 2 for hν=26--70 eV, spanning the Mo 4p→4d transition region. A broad Fano-like resonance appears at ∼42 eV in the constant-initial-state (CIS) intensity plot of the d z 2 peak near the valence-band maximum [∼2 eV binding energy (BE)], confirming its predominantly Mo 4d character. A second shoulder on the higher-hν side of the maximum in the d z 2 CIS intensity plot is suggested to result from transitions to unoccupied states in the 5sp band ∼10 eV above E F , by comparison with a partial-yield spectrum and previous inverse-photoemission data. The region of the valence band in the range 3--4.5-eV BE also exhibits resonant behavior, indicating Mo 4d character, although somewhat less than for the d z 2 peak. The 5--7-eV BE range does not exhibit resonance behavior at the Mo 4p edge and, therefore, contains negligible Mo 4d character. A feature at ∼30 eV in the CIS intensity plot for the 5--7-eV BE range could not be definitively assigned in this study, but may be due to a resonance between direct photoemission and a process involving absorption and autoionization of electronic states that contain Mo 5s and 5p character

  12. Experimental test of resonant absorption theory. Annual progress report, January 1, 1979-December 31, 1979

    International Nuclear Information System (INIS)

    Yablonovitch, E.

    1979-09-01

    New results are reported on the angular and energy spectrum of resonantly accelerated electrons from a shock front as measured by a miniature β-ray spectrometer. We have devised a multichannel electron collector based on printed circuit board technology. It has been multiplexed into a fast oscilloscope to provide a complete absolute spectrum on a single laser shot

  13. Optical absorption and electron spin resonance in natural, irradiated and heated spodumene

    International Nuclear Information System (INIS)

    Ito, A.S.; Isotani, S.

    1983-09-01

    Heat treatment and X and γ-Rays irradiation of lylac and colorless natural spodumene, LiAlSi 2 O 6 , have been studied. Irradiation produces a color change, from lylac or colorless to green. Irradiated samples heated at 200 0 C turn lylac and bleach at 400 0 C. Optical absorption spectra were decomposed into gaussian line shape bands and it is observed that green and lylac centers are simultaneously created by irradiation. These centers are independent from each other. Optical absorption, EPR and X-Ray fluorescence results show the spectra of impurities, responsible by the presence of the created centers and indicated Mn participation in the process of centers creation and destruction. Decay Kinetics of green and lylac centers have been studied and it is observed that simple Kinetic models do not apply to these cases. An empirical fit allowed the calculation of activation energies of the lylac and green centers decays. Discussions about the present results led us to propose a new model where the green and lylac centers are due to Mn 3+ ions in two different Al 3+ sites, whose absorption are intensified by the interaction with an electron trapped in a neighbour oxygen. (Author) [pt

  14. Signature of ferro–paraelectric transition in biferroic LuCrO{sub 3} from electron paramagnetic resonance and non-resonant microwave absorption

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, G., E-mail: memodin@yahoo.com [Escuela Superior de Física y Matemáticas del Instituto Politécnico Nacional, U.P.A.L.M, Edificio 9, Av. Instituto Politécnico Nacional S/N, San Pedro Zacatenco, México DF 07738 (Mexico); Montiel, H. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico de la Universidad Nacional Autónoma de México, Cd. Universitaria, A.P. 70-186, México DF 04510 (Mexico); Durán, A. [Centro de Nanociencias y Nanotecnología de la Universidad Nacional Autónoma de México, Km. 107, Carretera Tijuana-Ensenada, Apartado Postal 14, C.P. 22800 Ensenada, B.C. México (Mexico); Conde-Gallardo, A. [Departamento de Física, CINVESTAV-IPN, A.P. 14-740, México DF 07360 (Mexico); Zamorano, R. [Escuela Superior de Física y Matemáticas del Instituto Politécnico Nacional, U.P.A.L.M, Edificio 9, Av. Instituto Politécnico Nacional S/N, San Pedro Zacatenco, México DF 07738 (Mexico)

    2014-12-15

    An electron paramagnetic resonance (EPR) study in the polycrystalline biferroic LuCrO{sub 3} is carried out at X-band (8.8–9.8 GHz) in the 295–510 K temperature range. For all the temperatures, the EPR spectra show a single broad line attributable to Cr{sup 3+} (S = 3/2) ions. The onset of a ferro–paraelectric transition has been determined from the temperature dependence of the parameters deduced from EPR spectra: the peak-to-peak linewidth (ΔH{sub pp}), the g-factor and the integral intensity (I{sub EPR}). Magnetically modulated microwave absorption spectroscopy (MAMMAS) and low-field microwave absorption (LFMA) are used to give further information on this material, where these techniques give also evidence of the ferro–paraelectric transition; indicating a behavior in agreement with a diffuse phase transition. - Highlights: • LuCrO{sub 3} powders are obtained via auto-ignition synthesis. • EPR is employed to study the onset of the ferro–paraelectric transition. • MAMMAS and LFMA techniques are used to give further information on this material.

  15. Signature of ferro–paraelectric transition in biferroic LuCrO3 from electron paramagnetic resonance and non-resonant microwave absorption

    International Nuclear Information System (INIS)

    Alvarez, G.; Montiel, H.; Durán, A.; Conde-Gallardo, A.; Zamorano, R.

    2014-01-01

    An electron paramagnetic resonance (EPR) study in the polycrystalline biferroic LuCrO 3 is carried out at X-band (8.8–9.8 GHz) in the 295–510 K temperature range. For all the temperatures, the EPR spectra show a single broad line attributable to Cr 3+ (S = 3/2) ions. The onset of a ferro–paraelectric transition has been determined from the temperature dependence of the parameters deduced from EPR spectra: the peak-to-peak linewidth (ΔH pp ), the g-factor and the integral intensity (I EPR ). Magnetically modulated microwave absorption spectroscopy (MAMMAS) and low-field microwave absorption (LFMA) are used to give further information on this material, where these techniques give also evidence of the ferro–paraelectric transition; indicating a behavior in agreement with a diffuse phase transition. - Highlights: • LuCrO 3 powders are obtained via auto-ignition synthesis. • EPR is employed to study the onset of the ferro–paraelectric transition. • MAMMAS and LFMA techniques are used to give further information on this material

  16. Near resonant absorption by atoms in intense, fluctuating fields: [Progress report

    International Nuclear Information System (INIS)

    1989-01-01

    During the present grant period preparations for photon echo studies of the role of phase fluctuations of an optical driving field resonant with the 1 S 0 - 3 P 1 transition in 174 Yb are moving forward. This experimental study emphasizes the role of fluctuations as a decorrelating mechanism on a phased array of excited atoms. Improvements in laser stabilization and in the quality of the fluctuation spectrum have been carried out and the first spectroscopic measurements will be carried out during this grant year. In response to an important recent theoretical study we have also applied the phase fluctuation synthesizing capability to the study of the atomic sodium resonance fluorescence line profile, driven by a phase fluctuating laser. The measured fluctuations in the fluorescence, characterized in terms of the standard deviation of the fluorescence intensity, have an unexpected and strong dependence on detuning of the driving laser

  17. Study of hyperon-pion resonances from kaonic absorption with KLOE

    Directory of Open Access Journals (Sweden)

    Vázquez Doce Oton

    2015-01-01

    The study of the antiK-hadron interactions inside the drift chamber of KLOE was initiated in order to search for signals from the formation of deeply bound kaonic nuclear states and the study of resonances like the Λ(1405 and the Σ(1385, and constitute a first step towards the preparation of the AMADEUS experiment at DAFNE, the e+e− collider of the Frascati National Laboratories (Italy of INFN.

  18. R&D INVESTMENTS AND SPILLOVERS UNDER ENDOGENOUS ABSORPTIVE CAPACITY: COMPETITIVE R&D CANNOT TAKE FULL-ADVANTAGE OF COMPLEMENTARITY IN ABSORPTIVE CAPACITY WHILE COOPERATIVE R&D CAN

    Directory of Open Access Journals (Sweden)

    Mário A.P.M. Da Silva

    2018-03-01

    Full Text Available We show that the setting up of general conditions on complementarity in absorptive capacity gives rise to different, if not opposite Nash equilibrium outcomes to those found when absorptive capacity is assumed to be determined only by the similarity of R&D orientations. Firms that cooperate in R&D can take full-advantage of complementarity in R&D by adopting firm-specific R&D paths, which appears to contradict findings and predictions of existing theoretical literature on R&D and spillovers. Oddly, firms competing in R&D cannot gain the most from the potential of complementarity in knowledge by not choosing firm-specific R&D approaches in equilibrium under even milder conditions, which is contrary to another prediction of existing related models.

  19. Resonant absorption effects induced by polarized laser ligth irradiating thin foils in the tnsa regime of ion acceleration

    International Nuclear Information System (INIS)

    Torrisi, L.; Badziak, J.; Rosinski, M.; Zaras-Szydlowska, A.; Pfeifer, M.; Torrisi, A.

    2016-01-01

    Thin foils were irradiated by short pulsed lasers at intensities of 10 16−19 W/cm 2 in order to produce non-equilibrium plasmas and ion acceleration from the target-normal-sheath-acceleration (TNSA) regime. Ion acceleration in forward direction was measured by SiC detectors and ion collectors used in the time-of-flight configuration. Laser irradiations were employed using p-polarized light at different incidence angles with respect to the target surface and at different focal distances from the target surface. Measurements demonstrate that resonant absorption effects, due to the plasma wave excitations, enhance the plasma temperature and the ion acceleration with respect to those performed without to use of p-polarized light. Dependences of the ion flux characteristics on the laser energy, wavelength, focal distance and incidence angle will be reported and discussed

  20. Alcohol-catalyzed photoreduction of iron-porphyrin complexes revealed by resonance raman and absorption spectroscopies

    Science.gov (United States)

    Ogura, T.; Fidler, V.; Ozaki, Y.; Kitagawa, T.

    1990-06-01

    Photoreduction of Fe III(OEP) (2-MeIm) (OEP is octaethylporphyrin; 2-MeIm is 2-methylimidazole) was found to be catalyzed by a trace amount of MeOH present in Ch 2Cl 2 as a stabilizer. The absence of either 2-MeIm or MeOH in the CH 2Cl 2 solution of Fe III(OEP) X (X is Cl -, Br - or I -) leads to no photoreduction. The presence of MeOH in the Fe III(OEP) (2-MeIm) solution results in the appearance of a new absorption band at 585 nm, and when Raman scattering was excited at 590 nm, a new Raman band appeared at 524 cm -. This band exhibited an upshift by 4 cm - with 54Fe(OEP) (2-MeIm)(CH 3OH) and a downshift by 12 cm -1 with 56Fe(OEP)(2-MeIm) (CD 3OD) and was therefore assigned to the Fe III-MeOH stretching vibration. The excitation profile of this band gave a peak around 585 nm and accordingly, the new absorption band at 584 nm was assigned to a charge-transfer (CT) band from MeOH to the Fe III ion. It was most unexpected that the photoreduction did not occur upon laser illumination within the CT band.

  1. Resonant silicon nanoparticles for enhancement of light absorption and photoluminescence from hybrid perovskite films and metasurfaces.

    Science.gov (United States)

    Tiguntseva, E; Chebykin, A; Ishteev, A; Haroldson, R; Balachandran, B; Ushakova, E; Komissarenko, F; Wang, H; Milichko, V; Tsypkin, A; Zuev, D; Hu, W; Makarov, S; Zakhidov, A

    2017-08-31

    Recently, hybrid halide perovskites have emerged as one of the most promising types of materials for thin-film photovoltaic and light-emitting devices because of their low-cost and potential for high efficiency. Further boosting their performance without detrimentally increasing the complexity of the architecture is critically important for commercialization. Despite a number of plasmonic nanoparticle based designs having been proposed for solar cell improvement, inherent optical losses of the nanoparticles reduce photoluminescence from perovskites. Here we use low-loss high-refractive-index dielectric (silicon) nanoparticles for improving the optical properties of organo-metallic perovskite (MAPbI 3 ) films and metasurfaces to achieve strong enhancement of photoluminescence as well as useful light absorption. As a result, we observed experimentally a 50% enhancement of photoluminescence intensity from a perovskite layer with silicon nanoparticles and 200% enhancement for a nanoimprinted metasurface with silicon nanoparticles on top. Strong increase in light absorption is also demonstrated and described by theoretical calculations. Since both silicon nanoparticle fabrication/deposition and metasurface nanoimprinting techniques are low-cost, we believe that the developed all-dielectric approach paves the way to novel scalable and highly effective designs of perovskite based metadevices.

  2. Combined optical emission and resonant absorption diagnostics of an Ar-O{sub 2}-Ce-reactive magnetron sputtering discharge

    Energy Technology Data Exchange (ETDEWEB)

    El Mel, A.A. [Chimie des Interactions Plasma-Surface (ChIPS), Research Institute for Materials Science and Engineering, Université de Mons, Place du Parc 23, Mons B-7000 (Belgium); Institut des Matériaux Jean Rouxel, Université de Nantes, CNRS, 2 rue de la Houssinière B.P. 32229, Nantes Cedex 3 44322 (France); Ershov, S. [Chimie des Interactions Plasma-Surface (ChIPS), Research Institute for Materials Science and Engineering, Université de Mons, Place du Parc 23, Mons B-7000 (Belgium); Britun, N., E-mail: nikolay.britun@umons.ac.be [Chimie des Interactions Plasma-Surface (ChIPS), Research Institute for Materials Science and Engineering, Université de Mons, Place du Parc 23, Mons B-7000 (Belgium); Ricard, A. [Université de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, Toulouse Cedex 9 F-31062 (France); Konstantinidis, S. [Chimie des Interactions Plasma-Surface (ChIPS), Research Institute for Materials Science and Engineering, Université de Mons, Place du Parc 23, Mons B-7000 (Belgium); Snyders, R. [Chimie des Interactions Plasma-Surface (ChIPS), Research Institute for Materials Science and Engineering, Université de Mons, Place du Parc 23, Mons B-7000 (Belgium); Materia Nova Research Center, Parc Initialis, Avenue Copernic 1, Mons B-7000 (Belgium)

    2015-01-01

    We report the results on combined optical characterization of Ar-O{sub 2}-Ce magnetron sputtering discharges by optical emission and resonant absorption spectroscopy. In this study, a DC magnetron sputtering system equipped with a movable planar magnetron source with a Ce target is used. The intensities of Ar, O, and Ce emission lines, as well as the absolute densities of Ar metastable and Ce ground state atoms are analyzed as a function of the distance from the magnetron target, applied DC power, O{sub 2} content, etc. The absolute number density of the Ar{sup m} is found to decrease exponentially as a function of the target-to-substrate distance. The rate of this decrease is dependent on the sputtering regime, which should be due to the different collisional quenching rates of Ar{sup m} by O{sub 2} molecules at different oxygen contents. Quantitatively, the absolute number density of Ar{sup m} is found to be equal to ≈ 3 × 10{sup 8} cm{sup −3} in the metallic, and ≈ 5 × 10{sup 7} cm{sup −3} in the oxidized regime of sputtering, whereas Ce ground state densities at the similar conditions are found to be few times lower. The absolute densities of species are consistent with the corresponding deposition rates, which decrease sharply during the transition from metallic to poisoned sputtering regime. - Highlights: • Optical emission and resonant absorption spectroscopy are employed to study Ar-O{sub 2}-Ce magnetron sputtering discharges. • The density of argon metastables is found to decrease exponentially when increasing the target-to-substrate distance. • The collision-quenching rates of Ar{sup m} by O{sub 2} molecules at different oxygen contents is demonstrated. • The deposition rates of cerium and cerium oxide thin films decrease sharply during the transition from the metallic to the poisoned sputtering regime.

  3. Surface plasmon resonance enhanced light absorption and wavelength tuneable in gold-coated iron oxide spherical nanoparticle

    Science.gov (United States)

    Dasri, Thananchai; Chingsungnoen, Artit

    2018-06-01

    Surface plasmon in nano-sized particles, such as gold, silver, copper and their composites, has recently attracted a great deal of attention due to its possible uses in many applications, especially in life sciences. It is desirable for application devices with a tenability of surface plasmon wavelength and optical properties enhancement. This article presents enhanced optical light absorption and tunable wavelength in gold-coated magnetite (Fe3O4@Au core-shell) nanoparticles embedded in water using the theoretical method of discrete dipole approximation (DDA). The absorption spectra in the wavelengths from 350 to 900 nm were found to be the spectra obtained from Fe3O4@Au core-shell nanoparticles, and when compared with pure Fe3O4 nanoparticles, the surface plasmon resonance can be enhanced and tuned over the entire visible spectrum (viz. 350-800 nm) of the electromagnetic spectrum by varying the Au shell thickness (2-5 nm). Similarly, the Faraday rotation spectra can also be obtained.

  4. Förster resonance energy transfer, absorption and emission spectra in multichromophoric systems. III. Exact stochastic path integral evaluation.

    Science.gov (United States)

    Moix, Jeremy M; Ma, Jian; Cao, Jianshu

    2015-03-07

    A numerically exact path integral treatment of the absorption and emission spectra of open quantum systems is presented that requires only the straightforward solution of a stochastic differential equation. The approach converges rapidly enabling the calculation of spectra of large excitonic systems across the complete range of system parameters and for arbitrary bath spectral densities. With the numerically exact absorption and emission operators, one can also immediately compute energy transfer rates using the multi-chromophoric Förster resonant energy transfer formalism. Benchmark calculations on the emission spectra of two level systems are presented demonstrating the efficacy of the stochastic approach. This is followed by calculations of the energy transfer rates between two weakly coupled dimer systems as a function of temperature and system-bath coupling strength. It is shown that the recently developed hybrid cumulant expansion (see Paper II) is the only perturbative method capable of generating uniformly reliable energy transfer rates and emission spectra across a broad range of system parameters.

  5. X-ray absorption and resonant photoelectron spectroscopy of epitaxial Fe-doped SrTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Koehl, Annemarie; Lenser, Christian; Xu, Chencheng; Wicklein, Sebastian; Dittmann, Regina [Peter Gruenberg Institut 7, Forschungszentrum Juelich GmbH (Germany); Kajewski, Dariusz; Kubacki, Jurek; Szade, Jacek [A.Chelkowski Institute of Physics, University of Silesia, Katowic (Poland)

    2012-07-01

    In recent years resistive switching in transition metal oxides received a lot of research interest due to the proposed application as non-volatile data memory. SrTiO{sub 3} serves as a model system for the investigation of resistive switching due to the valency change mechanism. Frequently, slightly Fe doping is used, as it has shown to improve the switching properties. The focus of this study is the effect of Fe-doping of SrTiO{sub 3} in thin epitaxial films. Thin film samples with Fe concentration of 2 at.% and 5 at.% were prepared by pulsed laser deposition at varying substrate temperatures. The surface morphology of the films is studied with AFM. X-ray absorption spectroscopy is performed in total-electron and auger-electron yield offering different probing depths. Significant variations of the Fe-L edge between bulk and interface as well as after annealing are observed and discussed in terms of integration into the lattice and evolution of secondary phases. Resonant photoelectron spectroscopy at the absorption edge of Ti, O and Fe was used to determine the spectral contributions to the valence band. Most noteworthy we find significant spectral weight above the valence band, which can be attributed to Fe-states.

  6. A Determination of the 2200 m/s Absorption Cross Section and Resonance Integral of Arsenic by Pile Oscillator Technique

    Energy Technology Data Exchange (ETDEWEB)

    Sokolowski, E K; Bladh, R

    1969-02-15

    Pile oscillator measurements of heavy-water solutions of As, B, Mn and In have been carried out in two different neutron spectra in the R0 reactor. For B, Mn and In the 2200 m/s cross section values recommended in BNL-325 are given to within 1.5 % or less, while for As the stated uncertainty is 5 %. In the present work the BNL values for B, Mn and In were used to derive weighted mean calibration constants for the reactor, which were then in turn used for obtaining self-consistent cross section values for all four elements. The values thus obtained for B, Mn and In were within experimental error of the recommended BNL values. The absorption cross section for As is in good agreement with a recently published value for the activation cross section. The value for the resonance integral of As, derived from the present measurements, is in better agreement with calculations from resonance parameters than values reported earlier.

  7. Tunable plasmon-induced absorption effects in a graphene-based waveguide coupled with graphene ring resonators

    Science.gov (United States)

    Huang, Pei-Nian; Xia, Sheng-Xuan; Fu, Guang-Lai; Liang, Mei-Zhen; Qin, Meng; Zhai, Xiang; Wang, Ling-Ling

    2018-03-01

    In this paper, we propose a structure composed of two graphene waveguides and dual coupled graphene ring resonators (GRRs) to achieve a plasmon-induced absorption (PIA) effect. A three-level plasmonic system and a temporal coupled mode theory (CMT) are utilized to verify the simulation results. Moreover, a double-window-PIA effect can be conveniently attained by introducing another GRR with proper parameters to meet more specific acquirement in optical modulation process. The pronounced PIA resonances can be tuned in a number of ways, such as by adjusting the coupling distance between the GRRs and the couplings between the GRR and the waveguide, and tuning the radius and the Fermi energy of the GRRs. Besides, the produced PIA effect shows a high group delay up to - 1 . 87 ps, exhibiting a particularly prominent fast-light feature. Our results have potential applications in the realization of THz-integrated spectral control and graphene plasmonic devices such as sensors, filters, ultra-fast optical switches and so on.

  8. A Determination of the 2200 m/s Absorption Cross Section and Resonance Integral of Arsenic by Pile Oscillator Technique

    International Nuclear Information System (INIS)

    Sokolowski, E.K.; Bladh, R.

    1969-02-01

    Pile oscillator measurements of heavy-water solutions of As, B, Mn and In have been carried out in two different neutron spectra in the R0 reactor. For B, Mn and In the 2200 m/s cross section values recommended in BNL-325 are given to within 1.5 % or less, while for As the stated uncertainty is 5 %. In the present work the BNL values for B, Mn and In were used to derive weighted mean calibration constants for the reactor, which were then in turn used for obtaining self-consistent cross section values for all four elements. The values thus obtained for B, Mn and In were within experimental error of the recommended BNL values. The absorption cross section for As is in good agreement with a recently published value for the activation cross section. The value for the resonance integral of As, derived from the present measurements, is in better agreement with calculations from resonance parameters than values reported earlier

  9. Room temperature lasing unraveled by a strong resonance between gain and parasitic absorption in uniaxially strained germanium

    Science.gov (United States)

    Gupta, Shashank; Nam, Donguk; Vuckovic, Jelena; Saraswat, Krishna

    2018-04-01

    A complementary metal-oxide semiconductor compatible on-chip light source is the holy grail of silicon photonics and has the potential to alleviate the key scaling issues arising due to electrical interconnects. Despite several theoretical predictions, a sustainable, room temperature laser from a group-IV material is yet to be demonstrated. In this work, we show that a particular loss mechanism, inter-valence-band absorption (IVBA), has been inadequately modeled until now and capturing its effect accurately as a function of strain is crucial to understanding light emission processes from uniaxially strained germanium (Ge). We present a detailed model of light emission in Ge that accurately models IVBA in the presence of strain and other factors such as polarization, doping, and carrier injection, thereby revising the road map toward a room temperature Ge laser. Strikingly, a special resonance between gain and loss mechanisms at 4%-5% 〈100 〉 uniaxial strain is found resulting in a high net gain of more than 400 cm-1 at room temperature. It is shown that achieving this resonance should be the goal of experimental work rather than pursuing a direct band gap Ge.

  10. On the problem of negative dissipation of fast waves at the fundamental ion cyclotron resonance and the accuracy of absorption estimates

    International Nuclear Information System (INIS)

    Castejon, F.; Pavlov, S.S.; Swanson, D. G.

    2002-01-01

    Negative dissipation appears when ion cyclotron resonance (ICR) heating at first harmonic in a thermal plasma is estimated using some numerical schemes. The causes of the appearance of such a problem are investigated analytically and numerically in this work showing that the problem is connected with the accuracy with which the absorption coefficient at the first ICR harmonic is estimated. The corrections for the absorption estimation are presented for the case of quasiperpendicular propagation of fast wave in this frequency range. A method to solve the problem of negative dissipation is presented and, as a result, an enhancement of absorption is found for reactor-size plasmas

  11. Cavity resonance absorption in ultra-high bandwidth CRT deflection structure by a resistive load

    Science.gov (United States)

    Dunham, M.E.; Hudson, C.L.

    1993-05-11

    An improved ultra-high bandwidth helical coil deflection structure for a cathode ray tube is described comprising a first metal member having a bore therein, the metal walls of which form a first ground plane; a second metal member coaxially mounted in the bore of the first metal member and forming a second ground plane; a helical deflection coil coaxially mounted within the bore between the two ground planes; and a resistive load disposed in one end of the bore and electrically connected to the first and second ground planes, the resistive load having an impedance substantially equal to the characteristic impedance of the coaxial line formed by the two coaxial ground planes to inhibit cavity resonance in the structure within the ultra-high bandwidth of operation. Preferably, the resistive load comprises a carbon film on a surface of an end plug in one end of the bore.

  12. Measurement of the resonance escape probability; Mesure de l'absorption resonnante

    Energy Technology Data Exchange (ETDEWEB)

    Anthony, J P; Bacher, P; Lheureux, L; Moreau, J; Schmitt, A P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    The average cadmium ratio in natural uranium rods has been measured, using equal diameter natural uranium disks. These values correlated with independent measurements of the lattice buckling, enabled us to calculate values of the resonance escape probability for the G1 reactor with one or the other of two definitions. Measurements were performed on 26 mm and 32 mm rods, giving the following values for the resonance escape probability p: 0.8976 {+-} 0.005 and 0.912 {+-} 0.006 (d. 26 mm), 0.8627 {+-} 0.009 and 0.884 {+-} 0.01 (d. 32 mm). The influence of either definition on the lattice parameters is discussed, leading to values of the effective integral. Similar experiments have been performed with thorium rods. (author) [French] Nous avons mesure le rapport cadmium moyen dans des barres d'uranium a l'aide de disques d'uranium naturel de meme diametre que ces dernieres. Ces mesures nous ont permis, conjointement avec des mesures de Laplacien du reseau, de determiner deux facteurs antitrappes du reacteur G1 correspondant a deux definitions exposees. Les mesures ont ete faites sur deux diametres de barres 26 et 32 mm. Resultats: 0.8976 {+-} 0.005 and 0.912 {+-} 0.006 (d. 26 mm), 0.8627 {+-} 0.009 and 0.884 {+-} 0.01 (d. 32 mm). L'influence de ces deux definitions sur les divers parametres du reseau, est discutee. La determination de 'p' pour un diametre de barres d'uranium de 26 mm, et les mesures de variation de Laplacien, nous ont permis de calculer une valeur de l'integrale effective correspondant a chaque definition. Les mesures analogues faites sur des barres de thorium sont egalement indiquees. (auteur)

  13. Stochasticity of the energy absorption in the electron cyclotron resonance; Estocasticidad de la absorcion de energia en la resonancia electron-ciclotronica

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez T, C. [Departamento de Fisica, ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Hernandez A, O

    1998-07-01

    The energy absorption mechanism in cyclotron resonance of the electrons is a present problem, since it could be considered from the stochastic point of view or this related with a non-homogeneous but periodical of plasma spatial structure. In this work using the Bogoliubov average method for a multi periodical system in presence of resonances, the drift equations were obtained in presence of a RF field for the case of electron cyclotron resonance until first order terms with respect to inverse of its cyclotron frequency. The absorbed energy equation is obtained on part of electrons in a simple model and by drift method. It is showed the stochastic character of the energy absorption. (Author)

  14. Parametric resonances in the amplitude-modulated probe-field absorption spectrum of a two-level atom driven by a resonance amplitude- and phase-modulated pumping field

    International Nuclear Information System (INIS)

    Sushilov, N.V.; Kholodkevich, E.D.

    1995-01-01

    An analytical expression is derived for the polarization induced by a weak probe field with periodically modulated amplitude in a two-level medium saturated by a strong amplitude-and phase-modulated resonance field. It is shown that the absorption spectrum of the probe field includes parametric resonances, the maxima corresponding to the condition δ= 2nΓ-Ω w and the minima to that of δ= (2n + 1)Γ- w , where δ is the probe-field detuning front the resonance frequency, Ω w is the modulation frequency of the probe-field amplitude, and Γ is the transition line width, n = 1, 2, 3, hor-ellipsis. At the specific modulation parameters, a substantial region of negative values (i.e., the region of amplification without the population inversion) exists in the absorption spectrum of the probe field

  15. Inactivation of bacteriophage T1 by the Auger effect following phosphorus resonance absorption of monoenergetic synchrotron radiation

    International Nuclear Information System (INIS)

    Furusawa, Yoshiya; Maezawa, Hiroshi; Suzuki, Kenshi; Kobayashi, Katsumi; Suzuki, Masao; Hieda, Kotaro

    1992-01-01

    Killing effect on bacteriophage T1 by the Auger cascade of phosphorus in DNA following K shell photoabsorption was studied with monoenergetic X rays obtained from synchrotron radiations. Phages embedded in nutrient broth were irradiated under vacuum with X rays at the resonance peak (2,153 eV), and below (2,147 eV) and above (2,159 eV) the peak. The corresponding mean lethal exposures (D 0 ) were 554, 332 and 434 kR, respectively. The Auger enhancements, as an energy dependent fractional increment of phase sensitivity, were 0.67 at 2,153 eV and 0.28 at 2,159 eV. Using the DNA absorption spectrum measured in this experiment, photoionization cross sections of Scofield (17), and the Auger yield after creation of a K shell vacancy, the number of phosphorus Auger cascades in one phage DNA at D 0 were calculated to be 0.00, 0.98 and 0.25 at 2,147, 2,153 and 2,159 eV, respectively. Comparison between the Auger enhancement of phage killing and the number of Auger cascades indicated that one phosphorus Auger cascade in phage DNA caused about 0.41 (at 2,153 eV) or 0.84 (at 2,159 eV) lethal events

  16. Validation studies on quick analysis of MOX fuel by combination of laser induced breakdown spectroscopy and ablation resonance absorption spectroscopy

    International Nuclear Information System (INIS)

    Wakaida, Ikuo; Akaoka, Katsuaki; Miyabe, Masabumi; Kato, Masaaki; Otobe, Haruyoshi; Ohoba, Hironori; Khumaeni, Ali

    2014-01-01

    Research and development of laser based quick analysis without chemical analysis and neutron measurement for next-generation Minor Actinide containing MOX fuel has been carried out, and the basic performances by using un-irradiated MOX fuel were demonstrated. The glove box had been re-constructed and specialized for laser spectroscopy, and the remote spectroscopy of MOX sample contained several concentrations of Pu was performed. In elemental analysis by Laser Induced Breakdown Spectroscopy (LIBS) with high resolution spectrometer, relative error of 2.9% at 30% Pu and the detection lower limit of 2500ppm in natural U oxide were demonstrated with the operation time of 5 min. In isotope ratio analysis by Ablation Resonance Absorption Spectroscopy, tunable semiconductor laser system was constructed, and the performances such as relative deviation less than 1% in the ratio of "2"4"0Pu/"2"3"9Pu and the sensitivity of 30-100ppm in natural U were also accomplished with laser operation time of 3 to 5min. As for an elemental analysis of the simulated liquid sample, ultra-thin laminate flow was experimented as LIBS target, and the sensitivity comparable to conventional ICP-AES was confirmed. Present study includes the result of the entrusted project by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT). (author)

  17. Anionic and cationic redox and interfaces in batteries: Advances from soft X-ray absorption spectroscopy to resonant inelastic scattering

    Science.gov (United States)

    Yang, Wanli; Devereaux, Thomas P.

    2018-06-01

    Recent advances in battery science and technology have triggered both the challenges and opportunities on studying the materials and interfaces in batteries. Here, we review the recent demonstrations of soft X-ray spectroscopy for studying the interfaces and electrode materials. The focus of this review is on the recently developed mapping of resonant inelastic X-ray scattering (mRIXS) as a powerful probe of battery chemistry with superior sensitivity. Six different channels of soft X-ray absorption spectroscopy (sXAS) are introduced for different experimental purposes. Although conventional sXAS channels remain effective tools for quantitative analysis of the transition-metal states and surface chemistry, we elaborate the limitations of sXAS in both cationic and anionic redox studies. Particularly, based on experimental findings in various electrodes, we show that sXAS is unreliable for studying oxygen redox. We then demonstrate the mRIXS as a reliable technique for fingerprinting oxygen redox and summarize several crucial observations. We conclude that mRIXS is the tool-of-choice to study both the practical issue on reversibility of oxygen redox and the fundamental nature of bulk oxygen states. We hope this review clarifies the popular misunderstanding on oxygen sXAS results of oxide electrodes, and establishes a reliable technique for detecting oxygen redox through mRIXS.

  18. Study on the interactions of antiemetic drugs and 12-tungstophosphoric acid by absorption and resonance Rayleigh scattering spectra and their analytical applications

    Science.gov (United States)

    Wang, Yaqiong; Liu, Shaopu; Liu, Zhongfang; Yang, Jidong; Hu, Xiaoli

    2013-03-01

    In 0.1 mol L-1 HCl medium, antiemetic drugs (ATM), such as granisetron hydrochloride (GS) and tropisetron hydrochloride (TS), reacted with H3PW12O40·nH2O and formed 3:1 ion-association complex of [(ATM)3PW12O40], then self-aggregated into nanoparticles-[(ATM)3PW12O40]n with an average size of 100 nm. The reaction resulted in the enhancement of resonance Rayleigh scattering (RRS) and the absorption spectra. The increments of scattering intensity (ΔIRRS) and the change of absorbance (ΔA) were both directly proportional to the concentrations of ATM in certain ranges. Accordingly, two new RRS and spectrophotometric methods were proposed for ATM detection. The detection limits (3σ) of GS and TS were 3.2 ng mL-1 and 4.0 ng mL-1(RRS method), 112.5 ng mL-1 and 100.0 ng mL-1(spectrophotometric method). These two methods were applied to determine GS in orally disintegrating tablets and the results were in good agreement with the official method. The ground-state geometries and electronic structures of GS and TS were optimized by the hybrid density functional theory (DFT) method and the shape of [(ATM)3PW12O40]n was characterized by atomic force microscopy (AFM). Take the RRS method with higher sensitivity as an example, the reaction mechanism and the reasons for enhancement of scattering were discussed.

  19. Effects of pre-irradiation annealing at high temperature on optical absorption and electron paramagnetic resonance of natural pumpellyite mineral

    International Nuclear Information System (INIS)

    Javier-Ccallata, Henry; Filho, Luiz Tomaz; Sartorelli, Maria L.; Watanabe, Shigueo

    2013-01-01

    Highlights: •Natural pumpellyite mineral presents superposition bands around 900 and 1060 nm due Fe 2+ and Fe 3+ . •High temperature annealing influences the EPR and OA spectra. •The behavior of EPR line for 800 and 900 °C can be attributed to forbidden dd transitions due the Fe 3+ . -- Abstract: Natural silicate mineral of pumpellyite, Ca 2 MgAl 2 (SiO 4 )(Si 2 O 7 )(OH) 2 ·(H 2 O), point group A2/m, has been studied concerning high temperature annealing and γ-radiation effects on Optical Absorption (OA) and Electron Paramagnetic Resonance (EPR) properties. Chemical analysis revealed that besides Si, Al, Ca and Mg, other oxides i.e., Fe, Mn, Na, K, Ti and P are present in the structure as impurities. OA measurements of natural and annealed pumpellyite revealed several bands in the visible region due to spin forbidden transitions of Fe 2+ and Fe 3+ . The behaviour of bands around 900 and 1060 nm, with pre-annealing and γ radiation dose, indicating a transition Fe 2+ → e − + Fe 3+ . On the other hand, EPR measurements reveal six lines of Mn 2+ , and satellites due to hyperfine interaction, superimposed on the signal of Fe 3+ around of g = 2. For heat treatment from 800 °C the signal grows significantly and for 900 °C a strong signal of Fe 3+ hides all Mn 2+ lines. The strong growth of this signal indicates that the transitions are due to Fe 3+ dipole–dipole interactions

  20. Visual and Plasmon Resonance Absorption Sensor for Adenosine Triphosphate Based on the High Affinity between Phosphate and Zr(IV).

    Science.gov (United States)

    Qi, Wenjing; Liu, Zhongyuan; Zhang, Wei; Halawa, Mohamed Ibrahim; Xu, Guobao

    2016-10-12

    Zr(IV) can form phosphate and Zr(IV) (-PO₃ 2- -Zr 4+ -) complex owing to the high affinity between Zr(IV) with phosphate. Zr(IV) can induce the aggregation of gold nanoparticles (AuNPs), while adenosine triphosphate(ATP) can prevent Zr(IV)-induced aggregation of AuNPs. Herein, a visual and plasmon resonance absorption (PRA)sensor for ATP have been developed using AuNPs based on the high affinity between Zr(IV)with ATP. AuNPs get aggregated in the presence of certain concentrations of Zr(IV). After the addition of ATP, ATP reacts with Zr(IV) and prevents AuNPs from aggregation, enabling the detection of ATP. Because of the fast interaction of ATP with Zr(IV), ATP can be detected with a detection limit of 0.5 μM within 2 min by the naked eye. Moreover, ATP can be detected by the PRA technique with higher sensitivity. The A 520nm / A 650nm values in PRA spectra increase linearly with the concentrations of ATP from 0.1 μM to 15 μM (r = 0.9945) with a detection limit of 28 nM. The proposed visual and PRA sensor exhibit good selectivity against adenosine, adenosine monophosphate, guanosine triphosphate, cytidine triphosphate and uridine triphosphate. The recoveries for the analysis of ATP in synthetic samples range from 95.3% to 102.0%. Therefore, the proposed novel sensor for ATP is promising for real-time or on-site detection of ATP.

  1. Visual and Plasmon Resonance Absorption Sensor for Adenosine Triphosphate Based on the High Affinity between Phosphate and Zr(IV

    Directory of Open Access Journals (Sweden)

    Wenjing Qi

    2016-10-01

    Full Text Available Zr(IV can form phosphate and Zr(IV (–PO32−–Zr4+– complex owing to the high affinity between Zr(IV with phosphate. Zr(IV can induce the aggregation of gold nanoparticles (AuNPs, while adenosine triphosphate(ATP can prevent Zr(IV-induced aggregation of AuNPs. Herein, a visual and plasmon resonance absorption (PRAsensor for ATP have been developed using AuNPs based on the high affinity between Zr(IVwith ATP. AuNPs get aggregated in the presence of certain concentrations of Zr(IV. After the addition of ATP, ATP reacts with Zr(IV and prevents AuNPs from aggregation, enabling the detection of ATP. Because of the fast interaction of ATP with Zr(IV, ATP can be detected with a detection limit of 0.5 μM within 2 min by the naked eye. Moreover, ATP can be detected by the PRA technique with higher sensitivity. The A520nm/A650nm values in PRA spectra increase linearly with the concentrations of ATP from 0.1 μM to 15 μM (r = 0.9945 with a detection limit of 28 nM. The proposed visual and PRA sensor exhibit good selectivity against adenosine, adenosine monophosphate, guanosine triphosphate, cytidine triphosphate and uridine triphosphate. The recoveries for the analysis of ATP in synthetic samples range from 95.3% to 102.0%. Therefore, the proposed novel sensor for ATP is promising for real-time or on-site detection of ATP.

  2. Effects of pre-irradiation annealing at high temperature on optical absorption and electron paramagnetic resonance of natural pumpellyite mineral

    Energy Technology Data Exchange (ETDEWEB)

    Javier-Ccallata, Henry, E-mail: henrysjc@gmail.com [Escuela de Ingeniería Electrónica y Telecomunicaciones, Universidad Alas Peruanas Filial Arequipa, Urb. D. A. Carrión G-14, J. L. Bustamante y Rivero, Arequipa (Peru); Laboratório de Sistemas Nanoestruturados, Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina (Brazil); Filho, Luiz Tomaz [Departamento de Física Nuclear, Instituto de Física, Universidade de São Paulo, Rua do Matão, travessa R, 187, CEP 05508-900 São Paulo, SP (Brazil); Faculdade de Tecnologia e Ciências Exatas, Universidade São Judas Tadeu, Rua Taquari 546, São Paulo, SP (Brazil); Sartorelli, Maria L. [Laboratório de Sistemas Nanoestruturados, Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina (Brazil); Watanabe, Shigueo [Departamento de Física Nuclear, Instituto de Física, Universidade de São Paulo, Rua do Matão, travessa R, 187, CEP 05508-900 São Paulo, SP (Brazil)

    2013-09-15

    Highlights: •Natural pumpellyite mineral presents superposition bands around 900 and 1060 nm due Fe{sup 2+}and Fe{sup 3+}. •High temperature annealing influences the EPR and OA spectra. •The behavior of EPR line for 800 and 900 °C can be attributed to forbidden dd transitions due the Fe{sup 3+}. -- Abstract: Natural silicate mineral of pumpellyite, Ca{sub 2}MgAl{sub 2}(SiO{sub 4})(Si{sub 2}O{sub 7})(OH){sub 2}·(H{sub 2}O), point group A2/m, has been studied concerning high temperature annealing and γ-radiation effects on Optical Absorption (OA) and Electron Paramagnetic Resonance (EPR) properties. Chemical analysis revealed that besides Si, Al, Ca and Mg, other oxides i.e., Fe, Mn, Na, K, Ti and P are present in the structure as impurities. OA measurements of natural and annealed pumpellyite revealed several bands in the visible region due to spin forbidden transitions of Fe{sup 2+} and Fe{sup 3+}. The behaviour of bands around 900 and 1060 nm, with pre-annealing and γ radiation dose, indicating a transition Fe{sup 2+} → e{sup −} + Fe{sup 3+}. On the other hand, EPR measurements reveal six lines of Mn{sup 2+}, and satellites due to hyperfine interaction, superimposed on the signal of Fe{sup 3+} around of g = 2. For heat treatment from 800 °C the signal grows significantly and for 900 °C a strong signal of Fe{sup 3+} hides all Mn{sup 2+} lines. The strong growth of this signal indicates that the transitions are due to Fe{sup 3+} dipole–dipole interactions.

  3. Electron paramagnetic resonance and optical absorption study of V{sup 4+} centres in YVO{sub 4} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Garces, N Y [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Stevens, K T [Northrop Grumman Space Technology, Synoptics, Charlotte, NC 28273 (United States); Foundos, G K [Northrop Grumman Space Technology, Synoptics, Charlotte, NC 28273 (United States); Halliburton, L E [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States)

    2004-10-06

    Electron paramagnetic resonance (EPR) has been used to characterize three distinct V{sup 4+} centres in undoped Czochralski-grown yttrium orthovanadate (YVO{sub 4}) crystals. These EPR signals are observed at low temperatures, and their average c-axis splittings between adjacent {sup 51}V hyperfine lines are 40 G, 123 G, and 140 G. We refer to these centres as [V{sup 4+}]{sub A}, [V{sup 4+}]{sub B}, and [V{sup 4+}]{sub C}, respectively. The [V{sup 4+}]{sub A} and [V{sup 4+}]{sub B} centres are present in as-grown crystals. Exposure at 77 K to ionizing radiation (x-rays or an ultraviolet laser beam) destroys these centres and creates the [V{sup 4+}]{sub C} centres. The as-grown state of the crystal is restored upon returning to room temperature. Angular dependence data are used to determine the principal values and principal directions of the g tensor and the {sup 51}V hyperfine tensor for each of the centres. We suggest that the [V{sup 4+}]{sub A} centre is a V{sup 4+} ion adjacent to an oxygen vacancy and that the [V{sup 4+}]{sub B} centre is a V{sup 4+} ion substituting for a Y{sup 3+} ion (i.e. a vanadium antisite defect). The [V{sup 4+}]{sub C} centre is assigned to a V{sup 4+} ion at a regular vanadium site with a nearby stabilizing defect, possibly a Zr{sup 4+} on a Y{sup 3+} site. In as-grown crystals, there is a correlation between the number of [V{sup 4+}]{sub A} centres and the intensity (at 380 nm) of a broad near-edge optical absorption band. This band, now associated with oxygen vacancies, gives YVO{sub 4} a 'yellow' appearance.

  4. Investigation of the 34S(p,γ)35Cl reaction and resonant absorption applied to the excitation of bound states

    International Nuclear Information System (INIS)

    Sparks, R.J.

    1976-01-01

    The yield curve of the reaction 34 S(p,γ) 35 Cl has been measured over the energy range Esub(p) = 1.95 - 2.91 MeV. Proton energies and strengths of 84 resonances are given. The decay schemes of 38 selected resonances have been studied, and for these branching ratios and spin limits are presented. Angular distributions have been measured at four 34 S(p,γ) 35 Cl resonances, at Esub(x) = 8.63, 8.64, 8.95 and 9.08 MeV, giving spin-parity assignments Jsup(π) = 7/2 - , (3/2,5/2), 3/2 + and 5/2, respectively. Spins and parities have been determined for bound states at Esub(x) = 3.92, 4.11, 4.85 and 5.16 MeV, as Jsup(π) = 3/2 + , 7/2 + , (1/2,3/2), 7/2 - , respectively. Branching and mixing ratios have been obtained for the decay of the states at Esub(x) = 3.92, 4.11, 4.35 and 5.16 MeV. Transition strengths are presented for the first three of these. A resonant absorption experiment at the Esub(p) = 2.79 MeV resonance gives for the resonance width GAMMA = 65 +- 20 eV, and also determines the partial widths GAMMAsub(γ), GAMMAsub(p) and GAMMAsub(p1). The level at 7064.3 +- 0.5 keV in 208 Pb has been excited in a resonant absorption experiment by Doppler shifted γ-radiation from the 34 S(p,γ) 35 Cl reaction at Esub(p) = 1974 keV. (Auth.)

  5. Study of the dispersion phenomena connected with the absorption by recoilless nuclear resonance fluorescence; Etude des phenomenes de dispersion lies a l'absorption resonnante sans recul des noyaux atomiques

    Energy Technology Data Exchange (ETDEWEB)

    Imbert, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-12-01

    In nuclear resonance fluorescence as in the optical field abnormal dispersion curves are related to the absorption lines. It is possible, by using quadrupolar or magnetic splitting of the line in the case of recoilless resonance fluorescence (Moessbauer effect) to obtain differential dispersion effects between the two orthogonal linear or the two inverse circular components of the incident gamma radiation. These effects induce bi-refraction phenomena or Faraday rotation on the gamma beam, which have been studied on Fe-57 enriched absorbers. (author) [French] Comme dans le domaine optique, aux raies d'absorption de fluorescence resonnante des noyaux atomiques sont associees des courbes de dispersion anormale. Les decompositions des raies d'absorption de fluorescence resonnante sans recul (raies Moessbauer) par couplage quadrupolaire ou effet Zeeman permettent d'obtenir des effets dispersifs differentiels entre composantes lineaires orthogonales ou circulaires inverses du rayonnement gamma incident. Ces effets se traduisent par des phenomenes de birefringence ou de rotation Faraday, qui ont pu etre etudies sur des milieux enrichis en fer-57. (auteur)

  6. Determination of the quasi-TE mode (in-plane) graphene linear absorption coefficient via integration with silicon-on-insulator racetrack cavity resonators.

    Science.gov (United States)

    Crowe, Iain F; Clark, Nicholas; Hussein, Siham; Towlson, Brian; Whittaker, Eric; Milosevic, Milan M; Gardes, Frederic Y; Mashanovich, Goran Z; Halsall, Matthew P; Vijayaraghaven, Aravind

    2014-07-28

    We examine the near-IR light-matter interaction for graphene integrated cavity ring resonators based on silicon-on-insulator (SOI) race-track waveguides. Fitting of the cavity resonances from quasi-TE mode transmission spectra reveal the real part of the effective refractive index for graphene, n(eff) = 2.23 ± 0.02 and linear absorption coefficient, α(gTE) = 0.11 ± 0.01dBμm(-1). The evanescent nature of the guided mode coupling to graphene at resonance depends strongly on the height of the graphene above the cavity, which places limits on the cavity length for optical sensing applications.

  7. Anomaly in shape of resonance absorption lines of atoms with large fine-structure splitting of levels

    International Nuclear Information System (INIS)

    Parkhomenko, A.I.; yachev, S.P."" >Podyachev, S.P.; Privalov, T.I.; Shalagin, A.M.

    1997-01-01

    Absorption line of monochromatic radiation by atoms nonselective excitation by velocities under conditions of optical excitation of components of superfine structure of the basic electron state is considered. It is shown that the absorption line has unusual substructures for certain values of the basic state superfine desintegration. These substructures in the absorption spectrum may be pointed out by accounting the superfine structure of the electron excited state. The absorption spectra of monochromatic radiation close tot he D 1 - and D 2 -lines of the atomic rubidium are calculated

  8. Resonance

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2014-01-01

    A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice.......A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice....

  9. Molecular speciation of phosphorus in organic amendments and amended soils using nuclear magnetic resonance and X-ray absorption spectroscopies

    International Nuclear Information System (INIS)

    Ajibove, B.

    2007-01-01

    Characterization of phosphorus (P) in organic amendments is essential for environmentally sustainable fertilization of agricultural soils. The sequential chemical extraction (SCE) technique commonly used for P characterization does not provide any direct molecular information about P species. Studies were conducted to characterize P species in organic amendments and amended soils at a molecular level. The SCE was used to fractionate P in organic amendments including biosolids, hog, dairy and beef cattle manures, and poultry litter. The extracts were analyzed for total P and P species using inductively coupled plasma - optical emission spectroscopy (ICP-OES) and solution 31 P nuclear magnetic resonance (NMR) spectroscopy, respectively. The relative proportions of P species in intact organic amendments and residues after each extraction, and calcareous soils amended with organic amendments and monoammonium phosphate (MAP) were estimated using the synchrotron-based P 1s X-ray absorption near edge structure (XANES) spectroscopy. The solution 31 P NMR provided a detailed characterization of organic P in the non-labile NaOH and HCl fractions of organic amendments, but was limited in characterizing the labile fractions of most of these organic amendments due to their proneness to alkaline hydrolysis. The XANES analysis, however, identified the actual chemical species constituting the labile P that was only characterized as inorganic P or orthophosphates by sequential extraction and solution 31 P NMR. In the amended Vertisolic and Chernozemic soils, XANES analysis estimated 'soluble and adsorbed P' as the dominant P species. For the Vertisolic soil, both the unamended and soil amended with biosolids and MAP contained hydroxyapatite (HAP). In addition, soil amended with biosolids, hog and dairy manures contained β-tricalcium phosphate (TRICAL), a more soluble CaP than HAP. TRICAL was found in all amended soils except in that amended with hog manure, while HAP was present

  10. Electron spin resonance insight into broadband absorption of the Cu3Bi(SeO3)2O2Br metamagnet

    Science.gov (United States)

    Zorko, A.; Gomilšek, M.; Pregelj, M.; Ozerov, M.; Zvyagin, S. A.; Ozarowski, A.; Tsurkan, V.; Loidl, A.; Zaharko, O.

    2016-05-01

    Metamagnets, which exhibit a transition from a low-magnetization to a high-magnetization state induced by the applied magnetic field, have recently been highlighted as promising materials for controllable broadband absorption. Here we show results of a multifrequency electron spin resonance (ESR) investigation of the Cu3Bi(SeO3)2O2Br planar metamagnet on the kagome lattice. Its mixed antiferromagnetic/ferromagnetic phase is stabilized in a finite range of applied fields around 0.8 T at low temperatures and is characterized by enhanced microwave absorption. The absorption signal is non-resonant and its boundaries correspond to two critical fields that determine the mixed phase. With decreasing temperature these increase like the sublattice magnetization of the antiferromagnetic phase and show no frequency dependence between 100 and 480 GHz. On the contrary, we find that the critical fields depend on the magnetic-field sweeping direction. In particular, the higher critical field, which corresponds to the transition from the mixed to the ferromagnetic phase, shows a pronounced hysteresis effect, while such a hysteresis is absent for the lower critical field. The observed hysteresis is enhanced at lower temperatures, which suggests that thermal fluctuations play an important role in destabilizing the highly absorbing mixed phase.

  11. Procedure and code for calculating black control rods taking into account epithermal absorption, code CAS-1; Postupak i program za proracun crnih kontrolnih sipki, uzimajuci u obzir i epitermalnu apsorpciju, CAS-1

    Energy Technology Data Exchange (ETDEWEB)

    Martinc, R; Trivunac, N; Zivkovic, Z [Boris Kidric Institute of nuclear sciences Vinca, Belgrade (Yugoslavia)

    1964-12-15

    This report describes the computer code CAS-1, calculation method and procedure applied for calculating the black control rods taking into account the epithermal neutron absorption. Results obtained for supercell method applied for regular lattice reflected in the multiplication medium is part of this report in addition to the computer code manual.

  12. Resonance absorption measurements of atom concentrations in reacting gas mixtures. II. Calibration of microwave sources over a wide temperature range

    International Nuclear Information System (INIS)

    Chiang, C.; Lifshitz, A.; Skinner, G.B.; Wood, D.R.

    1979-01-01

    A series of experiments was carried out to calibrate three different microwave discharge lamps for analysis for D or H atoms, using Lyman-α absorption. Known concentrations of D atoms were produced in a shock tube by the reaction of 0.05--4 ppm D 2 with N 2 O in argon at 1800--3000 K. H atoms were produced by dissociation of 2,2,3,3-tetramethylbutane (10 ppm in argon) at 980--1140 K. These absorption data were compared with the absorption calculated from Lyman-α line shapes reported in an earlier paper, good agreement being found. These experiments provide a sound basis for obtaining the temperature and concentration dependence of the absorption coefficient over a wide temperature range, for H and D concentrations between 10 -12 and 10 -10 mole/cc

  13. Numerical studies of radiofrequency of the electromagnetic radiation power absorption in paediatrics undergoing brain magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    C. Subaar

    2017-07-01

    Full Text Available Magnetic resonance imaging current operating frequencies are above 100 kHz which is converted to heat through resistive tissue losses during imaging. The imaging is coupled with a concurring increase in temperature in patients. Magnetic resonance imaging of the brain has seen a rising clinical request during diagnosis and therefore become imperative that its safety issues be assessed. This study modelled Pennes' classical bio-heat equation using Finite Difference Method (FDM approach and with the help of MATLAB programming language, predicted three dimensional steady state temperature distributions in patients during magnetic resonance imaging. Sixty-four paediatric patients' referred for (head brain magnetic resonance imaging scan at 37 Military Hospital and the Diagnostic Center Limited, Ghana, pre-scan and post-scan temperatures were measured at the right tympanic. The numerically steady state temperature distribution during magnetic resonance imaging shows that there is excessive temperature elevation at the skin surface of the patients. The resulting skin heating during magnetic resonance imaging can reach dangerous level which suggests that the ohmic heating of tissue is greatest at the surface and minimal at the center of the patient's brain. Though the experimental results show that patients brain temperature increase after imaging, all measured temperatures were within acceptable safe levels.

  14. Resonances

    DEFF Research Database (Denmark)

    an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...

  15. RESONANCE

    Indian Academy of Sciences (India)

    born intoa mathematical family, (herfatherwasawell known mathematician), shehadto rebel ... ~mmy had to take special permission to be admitted as an auditor in ... She started working atthe Mathematical Institute at Erlangen without a formal ...

  16. Three-in-one approach towards efficient organic dye-sensitized solar cells: aggregation suppression, panchromatic absorption and resonance energy transfer

    Directory of Open Access Journals (Sweden)

    Jayita Patwari

    2017-08-01

    Full Text Available In the present study, protoporphyrin IX (PPIX and squarine (SQ2 have been used in a co-sensitized dye-sensitized solar cell (DSSC to apply their high absorption coefficients in the visible and NIR region of the solar spectrum and to probe the possibility of Förster resonance energy transfer (FRET between the two dyes. FRET from the donor PPIX to acceptor SQ2 was observed from detailed investigation of the excited-state photophysics of the dye mixture, using time-resolved fluorescence decay measurements. The electron transfer time scales from the dyes to TiO2 have also been characterized for each dye. The current–voltage (I–V characteristics and the wavelength-dependent photocurrent measurements of the co-sensitized DSSCs reveal that FRET between the two dyes increase the photocurrent as well as the efficiency of the device. From the absorption spectra of the co-sensitized photoanodes, PPIX was observed to be efficiently acting as a co-adsorbent and to reduce the dye aggregation problem of SQ2. It has further been proven by a comparison of the device performance with a chenodeoxycholic acid (CDCA added to a SQ2-sensitized DSSC. Apart from increasing the absorption window, the FRET-induced enhanced photocurrent and the anti-aggregating behavior of PPIX towards SQ2 are crucial points that improve the performance of the co-sensitized DSSC.

  17. Artifact suppression in electron paramagnetic resonance imaging of 14N- and 15N-labeled nitroxyl radicals with asymmetric absorption spectra

    Science.gov (United States)

    Takahashi, Wataru; Miyake, Yusuke; Hirata, Hiroshi

    2014-10-01

    This article describes an improved method for suppressing image artifacts in the visualization of 14N- and 15N-labeled nitroxyl radicals in a single image scan using electron paramagnetic resonance (EPR). The purpose of this work was to solve the problem of asymmetric EPR absorption spectra in spectral processing. A hybrid function of Gaussian and Lorentzian lineshapes was used to perform spectral line-fitting to successfully separate the two kinds of nitroxyl radicals. This approach can process the asymmetric EPR absorption spectra of the nitroxyl radicals being measured, and can suppress image artifacts due to spectral asymmetry. With this improved visualization method and a 750-MHz continuous-wave EPR imager, a temporal change in the distributions of a two-phase paraffin oil and water/glycerin solution system was visualized using lipophilic and hydrophilic nitroxyl radicals, i.e., 2-(14-carboxytetradecyl)-2-ethyl-4,4-dimethyl-3-oxazolidinyloxy (16-DOXYL stearic acid) and 4-hydroxyl-2,2,6,6-tetramethylpiperidine-d17-1-15N-1-oxyl (TEMPOL-d17-15N). The results of the two-phase separation experiment verified that reasonable artifact suppression could be achieved by the present method that deals with asymmetric absorption spectra in the EPR imaging of 14N- and 15N-labeled nitroxyl radicals.

  18. Absorption spectra of localized surface plasmon resonance observed in an inline/picoliter spectrometer cell fabricated by a near ultraviolet femtosecond laser

    Science.gov (United States)

    Shiraishi, Masahiko; Nishiyama, Michiko; Watanabe, Kazuhiro; Kubodera, Shoichi

    2018-03-01

    Absorption spectra based on localized surface plasmon resonance (LSPR) were obtained with an inline/picoliter spectrometer cell. The spectrometer cell was fabricated into an optical glass fiber by focusing a near UV (NUV) femtosecond laser pulses at a wavelength of 400 nm with an energy of 30 μJ. The laser beam was focused from two directions opposite to each other to fabricate a through-hole spectrometer cell. A diameter of the cell was approximately 3 μm, and the length was approximately 62.5 μm, which was nearly equal to the core diameter of the optical fiber. Liquid solution of gold nanoparticles (GNPs) with a diameter of 5-10 nm was injected into the spectrometer cell with its volume of 0.4 pL. The absorption peak centered at 518 nm was observed. An increase of absorption associated with the increase of the number of nanoparticles was in agreement with the numerical calculation based on the Lambert-Beer law.

  19. Effects of conjugation length and resonance enhancement on two-photon absorption in phenylene–vinylene oligomers

    DEFF Research Database (Denmark)

    Johnsen, Mette; Paterson, M.J.; Arnbjerg, J.

    2008-01-01

    . This phenomenon of the so-called resonance enhancement allows for greater control in obtaining an optimal response when using existing two-photon chromophores, and provides a much-needed guide for the systematic development and efficient use of two-photon singlet oxygen sensitizers....

  20. Combined Brillouin light scattering and microwave absorption study of magnon-photon coupling in a split-ring resonator/YIG film system

    Energy Technology Data Exchange (ETDEWEB)

    Klingler, S., E-mail: stefan.klingler@wmi.badw.de; Maier-Flaig, H.; Weiler, M. [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meißner-Straße 8, 85748 Garching (Germany); Physik-Department, Technische Universität München, 85748 Garching (Germany); Gross, R.; Huebl, H.; Goennenwein, S. T. B. [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meißner-Straße 8, 85748 Garching (Germany); Physik-Department, Technische Universität München, 85748 Garching (Germany); Nanosystems Initiative Munich (NIM), 80799 Munich (Germany); Hu, C.-M. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T2N2 (Canada)

    2016-08-15

    Microfocused Brillouin light scattering (BLS) and microwave absorption (MA) are used to study magnon-photon coupling in a system consisting of a split-ring microwave resonator and an yttrium iron garnet (YIG) film. The split-ring resonator is defined by optical lithography and loaded with a 1 μm-thick YIG film grown by liquid phase epitaxy. BLS and MA spectra of the hybrid system are simultaneously recorded as a function of the applied magnetic field magnitude and microwave excitation frequency. Strong coupling of the magnon and microwave resonator modes is found with a coupling strength of g{sub eff} /2π = 63 MHz. The combined BLS and MA data allow us to study the continuous transition of the hybridized modes from a purely magnonic to a purely photonic mode by varying the applied magnetic field and microwave frequency. Furthermore, the BLS data represent an up-conversion of the microwave frequency coupling to optical frequencies.

  1. Magnetization dynamics in La{sub 0.67}Ca{sub 0.33}MnO{sub 3} epitaxial films probed with resonant and non-resonant microwave absorption

    Energy Technology Data Exchange (ETDEWEB)

    Porwal, Rajni; Pant, R. P.; Budhani, R. C., E-mail: rcb@iitk.ac.in [National Physical Laboratory, Council of Scientific and Industrial Research, Dr K S Krishnan Marg, New Delhi-110012 (India)

    2015-01-07

    Temperature (T) dependent microwave absorption measurements are performed on La{sub 0.67}Ca{sub 0.33}MnO{sub 3} (LCMO) epitaxial thin films of thickness 100 and 200 nm in an electron paramagnetic resonance spectrometer operating in X-band. The resonant absorption peak is monitored for out-of-plane (H{sup ⊥}) and in-plane (H{sup ∥}) dc magnetic field (H) as the system goes through magnetic ordering. These data suggest a resilient transformation to the ferromagnetic (FM) phase in the vicinity of the Curie temperature (T{sub C}), indicative of a phase separation, which is dominant in the thinner film. The saturation magnetization is calculated from SQUID magnetometry on the same film. A pronounced zero-field absorption is seen in H{sup ∥} geometry displaying anomalous growth in 100 nm film at T < T{sub C}. This feature is correlated with the magneto-conductivity of the manganite which is colossal in the vicinity of T{sub C} in the well-ordered film of thickness 200 nm. Signature of standing spin wave modes is seen in H{sup ⊥} measurements which are analyzed to calculate the spin wave stiffness constant D(T) in the limit of zero temperature. The same is also inferred from the decay of equilibrium magnetization in the framework of Bloch law. These studies reveal that a bulk like LCMO is obtained in the fully relaxed thicker films.

  2. Electromagnetic resonance modes on a two-dimensional tandem grating and its application for broadband absorption in the visible spectrum.

    Science.gov (United States)

    Han, Sunwoo; Lee, Bong Jae

    2016-01-25

    In this work, we numerically investigate the electromagnetic resonances on two-dimensional tandem grating structures. The base of a tandem grating consists of an opaque Au substrate, a SiO(2) spacer, and a Au grating (concave type); that is, a well-known fishnet structure forming Au/SiO(2)/Au stack. A convex-type Au grating (i.e., topmost grating) is then attached on top of the base fishnet structure with or without additional SiO(2) spacer, resulting in two types of tandem grating structures. In order to calculate the spectral reflectance and local magnetic field distribution, the finite-difference time-domain method is employed. When the topmost Au grating is directly added onto the base fishnet structure, the surface plasmon and magnetic polariton in the base structure are branched out due to the geometric asymmetry with respect to the SiO(2) spacer. If additional SiO(2) spacer is added between the topmost Au grating and the base fishnet structure, new magnetic resonance modes appear due to coupling between two vertically aligned Au/SiO(2)/Au stacks. With the understanding of multiple electromagnetic resonance modes on the proposed tandem grating structures, we successfully design a broadband absorber made of Au and SiO(2) in the visible spectrum.

  3. Nickel complexes of o-amidochalcogenophenolate(2-)/o-iminochalcogenobenzosemiquinonate(1-) pi-radical: synthesis, structures, electron spin resonance, and x-ray absorption spectroscopic evidence.

    Science.gov (United States)

    Hsieh, Chung-Hung; Hsu, I-Jui; Lee, Chien-Ming; Ke, Shyue-Chu; Wang, Tze-Yuan; Lee, Gene-Hsiang; Wang, Yu; Chen, Jin-Ming; Lee, Jyh-Fu; Liaw, Wen-Feng

    2003-06-16

    The preparation of complexes trans-[Ni(-SeC(6)H(4)-o-NH-)(2)](-) (1), cis-[Ni(-TeC(6)H(4)-o-NH-)(2)](-) (2), trans-[Ni(-SC(6)H(4)-o-NH-)(2)](-) (3), and [Ni(-SC(6)H(4)-o-S-)(2)](-) (4) by oxidative addition of 2-aminophenyl dichalcogenides to anionic [Ni(CO)(SePh)(3)](-) proves to be a successful approach in this direction. The cis arrangement of the two tellurium atoms in complex 2 is attributed to the intramolecular Te.Te contact interaction (Te.Te contact distance of 3.455 A). The UV-vis electronic spectra of complexes 1 and 2 exhibit an intense absorption at 936 and 942 nm, respectively, with extinction coefficient epsilon > 10000 L mol(-)(1) cm(-)(1). The observed small g anisotropy, the principal g values at g(1) = 2.036, g(2) = 2.062, and g(3) = 2.120 for 1 and g(1) = 2.021, g(2) = 2.119, and g(3) = 2.250 for 2, respectively, indicates the ligand radical character accompanied by the contribution of the singly occupied d orbital of Ni(III). The X-ray absorption spectra of all four complexes show L(III) peaks at approximately 854.5 and approximately 853.5 eV. This may indicate a variation of contribution of the Ni(II)-Ni(III) valence state. According to the DFT calculation, the unpaired electron of complex 1 and 2 is mainly distributed on the 3d(xz)() orbital of the nickel ion and on the 4p(z)() orbital of selenium (tellurium, 5p(z)()) as well as the 2p(z)() orbital of nitrogen of the ligand. On the basis of X-ray structural data, UV-vis absorption, electron spin resonance, magnetic properties, DFT computation, and X-ray absorption (K- and L-edge) spectroscopy, the monoanionic trans-[Ni(-SeC(6)H(4)-o-NH-)(2)](-) and cis-[Ni(-TeC(6)H(4)-o-NH-)(2)](-) complexes are appositely described as a resonance hybrid form of Ni(III)-bis(o-amidochalcogenophenolato(2-)) and Ni(II)-(o-amidochalcogenophenolato(2-))-(o-iminochalcogenobenzosemiquinonato(1-) pi-radical; i.e., complexes 1 and 2 contain delocalized oxidation levels of the nickel ion and ligands.

  4. 3rd harmonic electron cyclotron resonant heating absorption enhancement by 2nd harmonic heating at the same frequency in a tokamak

    International Nuclear Information System (INIS)

    Gnesin, S; Coda, S; Goodman, T P; Decker, J; Peysson, Y; Mazon, D

    2012-01-01

    The fundamental mechanisms responsible for the interplay and synergy between the absorption dynamics of extraordinary-mode electron cyclotron waves at two different harmonic resonances (the 2nd and 3rd) are investigated in the TCV tokamak. An enhanced 3rd harmonic absorption in the presence of suprathermal electrons generated by 2nd harmonic heating is predicted by Fokker–Planck simulations, subject to complex alignment requirements in both physical space and momentum space. The experimental signature for the 2nd/3rd harmonic synergy is sought through the suprathermal bremsstrahlung emission in the hard x-ray range of photon energy. Using a synthetic diagnostic, the emission variation due to synergy is calculated as a function of the injected power and of the radial transport of suprathermal electrons. It is concluded that in the present experimental setup a synergy signature has not been unambiguously detected. The detectability of the synergy is then discussed with respect to variations and uncertainties in the plasma density and effective charge in view of future optimized experiments. (paper)

  5. Neural Correlates of a Perspective-taking Task Using in a Realistic Three-dimmensional Environment Based Task: A Pilot Functional Magnetic Resonance Imaging Study.

    Science.gov (United States)

    Agarwal, Sri Mahavir; Shivakumar, Venkataram; Kalmady, Sunil V; Danivas, Vijay; Amaresha, Anekal C; Bose, Anushree; Narayanaswamy, Janardhanan C; Amorim, Michel-Ange; Venkatasubramanian, Ganesan

    2017-08-31

    Perspective-taking ability is an essential spatial faculty that is of much interest in both health and neuropsychiatric disorders. There is limited data on the neural correlates of perspective taking in the context of a realistic three-dimensional environment. We report the results of a pilot study exploring the same in eight healthy volunteers. Subjects underwent two runs of an experiment in a 3 Tesla magnetic resonance imaging (MRI) involving alternate blocks of a first-person perspective based allocentric object location memory task (OLMT), a third-person perspective based egocentric visual perspective taking task (VPRT), and a table task (TT) that served as a control. Difference in blood oxygen level dependant response during task performance was analyzed using Statistical Parametric Mapping software, version 12. Activations were considered significant if they survived family-wise error correction at the cluster level using a height threshold of p <0.001, uncorrected at the voxel level. A significant difference in accuracy and reaction time based on task type was found. Subjects had significantly lower accuracy in VPRT compared to TT. Accuracy in the two active tasks was not significantly different. Subjects took significantly longer in the VPRT in comparison to TT. Reaction time in the two active tasks was not significantly different. Functional MRI revealed significantly higher activation in the bilateral visual cortex and left temporoparietal junction (TPJ) in VPRT compared to OLMT. The results underscore the importance of TPJ in egocentric manipulation in healthy controls in the context of reality-based spatial tasks.

  6. Förster resonance energy transfer, absorption and emission spectra in multichromophoric systems. II. Hybrid cumulant expansion.

    Science.gov (United States)

    Ma, Jian; Moix, Jeremy; Cao, Jianshu

    2015-03-07

    We develop a hybrid cumulant expansion method to account for the system-bath entanglement in the emission spectrum in the multi-chromophoric Förster transfer rate. In traditional perturbative treatments, the emission spectrum is usually expanded with respect to the system-bath coupling term in both real and imaginary time. This perturbative treatment gives a reliable absorption spectrum, where the bath is Gaussian and only the real-time expansion is involved. For the emission spectrum, the initial state is an entangled state of the system plus bath. Traditional perturbative methods are problematic when the excitations are delocalized and the energy gap is larger than the thermal energy, since the second-order expansion cannot predict the displacement of the bath. In the present method, the real-time dynamics is carried out by using the 2nd-order cumulant expansion method, while the displacement of the bath is treated more accurately by utilizing the exact reduced density matrix of the system. In a sense, the hybrid cumulant expansion is based on a generalized version of linear response theory with entangled initial states.

  7. Balancing Power Absorption and Structural Loading for a Novel Fixed-Bottom Wave Energy Converter with Nonideal Power Take-Off in Regular Waves: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Tom, Nathan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Yu, Yi-Hsiang [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wright, Alan D [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-06-08

    In this work, the net power delivered to the grid from a nonideal power take-off (PTO) is introduced followed by a review of the pseudo-spectral control theory. A power-to-load ratio, used to evaluate the pseudo-spectral controller performance, is discussed, and the results obtained from optimizing a multiterm objective function are compared against results obtained from maximizing the net output power to the grid. Simulation results are then presented for four different oscillating wave energy converter geometries to highlight the potential of combing both geometry and PTO control to maximize power while minimizing loads.

  8. Total photon absorption

    International Nuclear Information System (INIS)

    Carlos, P.

    1985-06-01

    The present discussion is limited to a presentation of the most recent total photonuclear absorption experiments performed with real photons at intermediate energy, and more precisely in the region of nucleon resonances. The main sources of real photons are briefly reviewed and the experimental procedures used for total photonuclear absorption cross section measurements. The main results obtained below 140 MeV photon energy as well as above 2 GeV are recalled. The experimental study of total photonuclear absorption in the nuclear resonance region (140 MeV< E<2 GeV) is still at its beginning and some results are presented

  9. Controlling successive ionic layer absorption and reaction cycles to optimize silver nanoparticle-induced localized surface plasmon resonance effects on the paper strip

    Science.gov (United States)

    Lee, Jae-Chul; Kim, Wansun; Park, Hun-Kuk; Choi, Samjin

    2017-03-01

    This study investigates why a silver nanoparticle (SNP)-induced surface-enhanced Raman scattering (SERS) paper chip fabricated at low successive ionic layer absorption and reaction (SILAR) cycles leads to a high SERS enhancement factor (7 × 108) with an inferior nanostructure and without generating a hot spot effect. The multi-layered structure of SNPs on cellulose fibers, verified by magnified scanning electron microscopy (SEM) and analyzed by a computational simulation method, was hypothesized as the reason. The pattern of simulated local electric field distribution with respect to the number of SILAR cycles showed good agreement with the experimental Raman intensity, regardless of the wavelength of the excitation laser sources. The simulated enhancement factor at the 785-nm excitation laser source (2.8 × 109) was 2.5 times greater than the experimental enhancement factor (1.1 × 109). A 532-nm excitation laser source exhibited the highest maximum local electric field intensity (1.9 × 1011), particularly at the interparticle gap called a hot spot. The short wavelength led to a strong electric field intensity caused by strong electromagnetic coupling arising from the SNP-induced local surface plasmon resonance (LSPR) effects through high excitation energy. These findings suggest that our paper-based SILAR-fabricated SNP-induced LSPR model is valid for understanding SNP-induced LSPR effects.

  10. Electron scattering by an atom in the field of resonant laser radiation

    International Nuclear Information System (INIS)

    Agre, M.; Rapoport, L.

    1982-01-01

    The collision of an electron with an atom in the field of intense electromagnetic radiation that is at resonance with two atomic multiplets is investigated theoretically. Expressions are obtained for the amplitudes of the elastic and inelastic scattering with emission (absorption) of photons. The case of a ground state at resonance with a doublet is considered in detail. It is shown that photon absorption takes place predominantly in the case of resonance in inelastic transitions from a state of the lower multiplet, and photon emission takes place in transitions from a state of the upper multiplet

  11. On the fundamentals of winning virtuous strategies creation toward leveraged buyout transactions implementation during private equity investment in conditions of resonant absorption of discrete information in diffusion - type financial system with induced nonlinearities

    OpenAIRE

    Ledenyov, Dimitri O.; Ledenyov, Viktor O.

    2014-01-01

    The authors perform an original research on the fundamentals of winning virtuous strategies creation toward the leveraged buyout transactions implementation during the private equity investment in the conditions of the resonant absorption of discrete information in the diffusion - type financial system with the induced nonlinearities at the influences by the Schumpeterian creative disruption processes in the free market economy. We propose that the money is a financial computing process, whic...

  12. Electric-dipole absorption resonating with longitudinal optical phonon-plasmon system and its effect on dispersion relations of interface phonon polariton modes in metal/semiconductor-stripe structures

    Science.gov (United States)

    Sakamoto, Hironori; Takeuchi, Eito; Yoshida, Kouki; Morita, Ken; Ma, Bei; Ishitani, Yoshihiro

    2018-01-01

    Interface phonon polaritons (IPhPs) in nano-structures excluding metal components are thoroughly investigated because they have lower loss in optical emission or absorption and higher quality factors than surface plasmon polaritons. In previous reports, it is found that strong infrared (IR) absorption is based on the interaction of p-polarized light and materials, and the resonance photon energy highly depends on the structure size and angle of incidence. We report the optical absorption by metal/semiconductor (bulk-GaAs and thin film-AlN)-stripe structures in THz to mid-IR region for the electric field of light perpendicular to the stripes, where both of s- and p-polarized light are absorbed. The absorption resonates with longitudinal optical (LO) phonon or LO phonon-plasmon coupling (LOPC) modes, and thus is independent of the angle of incidence or structure size. This absorption is attributed to the electric dipoles by the optically induced polarization charges at the metal/semiconductor, heterointerfaces, or interfaces of high electron density layers and depression ones. The electric permittivity is modified by the formation of these dipoles. It is found to be indispensable to utilize our form of altered permittivity to explain the experimental dispersion relations of metal/semiconductor-IPhP and SPhP in these samples. This analysis reveals that the IPhPs in the stripe structures of metal/AlN-film on a SiC substrate are highly confined in the AlN film, while the permittivity of the structures of metal/bulk-GaAs is partially affected by the electric-dipoles. The quality factors of the electric-dipole absorption are found to be 42-54 for undoped samples, and the value of 62 is obtained for Al/AlN-IPhP. It is thought that metal-contained structures are not obstacles to mode energy selectivity in phonon energy region of semiconductors.

  13. Controlling enhanced absorption in graphene metamaterial

    Science.gov (United States)

    Zhou, Qihui; Liu, Peiguo; Bian, Li-an; Liu, Hanqing; Liu, Chenxi; Chen, Genghui

    2018-04-01

    In this paper, a controllable terahertz (THz) metamaterial absorber (MA) is designed with the circuit analog method. Taking advantage of the patterned graphene on SiO2/doped Si/polyimide substrates with a gold reflector, the controllable MA achieves perfect absorption at 0.75 THz. The chemical potential of graphene is regulated by controlling the voltage between graphene and doped Si layers. As the chemical potential varies from 0 eV to 0.5 eV, the MA is changed from reflection (0.99). The distributions of surface current and electric field are illustrated to analyze the resonant characteristic of patterned graphene. According to the resonant characteristic, we introduce patterned graphene elements with different dimension in a unit cell, which effectively extends the effective absorption bandwidth (absorption > 0 . 9) from 0.67-0.93 THz to 0.52-0.95 THz. Moreover, replacing part of the graphene structure with gold, the switchable MA is turned into a frequency tunable MA. The absorption peak moves from 0.62 THz to 0.92 THz as the chemical potential increases from 0.1 eV to 0.5 eV. These designs overcome limitation of traditional absorbers and exhibit great potentials in many practical applications.

  14. Analytical approximations for wide and narrow resonances

    International Nuclear Information System (INIS)

    Suster, Luis Carlos; Martinez, Aquilino Senra; Silva, Fernando Carvalho da

    2005-01-01

    This paper aims at developing analytical expressions for the adjoint neutron spectrum in the resonance energy region, taking into account both narrow and wide resonance approximations, in order to reduce the numerical computations involved. These analytical expressions, besides reducing computing time, are very simple from a mathematical point of view. The results obtained with this analytical formulation were compared to a reference solution obtained with a numerical method previously developed to solve the neutron balance adjoint equations. Narrow and wide resonances of U 238 were treated and the analytical procedure gave satisfactory results as compared with the reference solution, for the resonance energy range. The adjoint neutron spectrum is useful to determine the neutron resonance absorption, so that multigroup adjoint cross sections used by the adjoint diffusion equation can be obtained. (author)

  15. Analytical approximations for wide and narrow resonances

    Energy Technology Data Exchange (ETDEWEB)

    Suster, Luis Carlos; Martinez, Aquilino Senra; Silva, Fernando Carvalho da [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear]. E-mail: aquilino@lmp.ufrj.br

    2005-07-01

    This paper aims at developing analytical expressions for the adjoint neutron spectrum in the resonance energy region, taking into account both narrow and wide resonance approximations, in order to reduce the numerical computations involved. These analytical expressions, besides reducing computing time, are very simple from a mathematical point of view. The results obtained with this analytical formulation were compared to a reference solution obtained with a numerical method previously developed to solve the neutron balance adjoint equations. Narrow and wide resonances of U{sup 238} were treated and the analytical procedure gave satisfactory results as compared with the reference solution, for the resonance energy range. The adjoint neutron spectrum is useful to determine the neutron resonance absorption, so that multigroup adjoint cross sections used by the adjoint diffusion equation can be obtained. (author)

  16. Total photon absorption

    International Nuclear Information System (INIS)

    Carlos, P.

    1985-01-01

    Experimental methods using real photon beams for measurements of total photonuclear absorption cross section σ(Tot : E/sub γ/) are recalled. Most recent σ(Tot : E/sub γ/)results for complex nuclei and in the nucleon resonance region are presented

  17. Taking antacids

    Science.gov (United States)

    Heartburn - antacids; Reflux - antacids; GERD - antacids ... Antacids are a good treatment for heartburn that occurs once in a while. Take antacids about 1 hour after eating or when you have heartburn. If you are taking ...

  18. Coherent Population Trapping Resonances in Cs Atomic Vapor Layers of Micrometric Thickness

    Directory of Open Access Journals (Sweden)

    A. Krasteva

    2011-01-01

    Full Text Available We report on a novel behavior of the electromagnetically induced absorption (EIA resonance observed on the D2 line of Cs for atoms confined in cells with micrometric thickness. With the enhancement of light intensity, the EIA resonance amplitude suffers from fast reduction, and even at very low intensity (W < 1 mW/cm2, resonance sign reversal takes place and electromagnetically induced transparency (EIT resonance is observed. Similar EIA resonance transformation to EIT one is not observed in conventional cm-size cells. A theoretical model is proposed to analyze the physical processes behind the EIA resonance sign reversal with light intensity. The model involves elastic interactions between Cs atoms as well as elastic interaction of atom micrometric-cell windows, both resulting in depolarization of excited state which can lead to the new observations. The effect of excited state depolarization is confirmed also by the fluorescence (absorption spectra measurement in micrometric cells with different thicknesses.

  19. Calculation of self-absorption coefficients of calcium resonance lines in the case of a CaCl2-water plasma

    International Nuclear Information System (INIS)

    Hannachi, R.; Cressault, Y.; Teulet, Ph.; Gleizes, A.; Lakhdar, Z. Ben

    2008-01-01

    The resonance escape factors for the lines emitted by a neutral calcium atom Ca I at 4226.73 A and of ionic calcium Ca II at 3933.66 A and at 3968.47 A are calculated assuming a Voigt profile and in the case of CaCl 2 -water plasma. The dependence of the escape factor on the optical thickness f 0 from the line center which itself depends on the two main spectral line shape broadening mechanisms (pressure and Doppler effects) are considered. The variation of the resonance escape factors with the temperature, the CaCl 2 molar proportion and the size of the plasma are also investigated. This calculation is useful for the application of Laser-Induced Breakdown Spectroscopy in the quantitative analysis of elemental composition. Its application allows us to reduce the non-linearities in the relation between resonance lines intensities of calcium in our case and its concentration

  20. Nonlinear cyclotron absorption and stimulated scattering

    International Nuclear Information System (INIS)

    Chung, T.H.

    1986-01-01

    In electron cyclotron resonance heating (ECRH), wave sources heating a plasma linearly with respect to intensity; but as the intensity of ECRH gets larger, there might appear nonlinear effects that would result in cutoff of net absorption. This thesis uses quantum mechanical theory to derive a threshold microwave intensity for nonlinear absorption. The quantum mechanical theory estimates that the threshold microwave intensity for nonlinear absorption is about 10 5 watts/cm 2 for a microwave heating experiment (T/sub e/ = 100 ev, λ = 3,783 cm, B = 2.5 kG). This value seems large considering the present power capabilities of microwave sources (10 2 ∼ 10 3 watts/cm 2 ), but for a low temperature plasma, this threshold will go down. There is another nonlinear phenomenon called stimulated cyclotron scattering that enhances photon scattering by electrons gyrating in a magnetic field. This is expected to prevent incoming photons from arriving at the central region of the fusion plasma, where absorption mainly takes place. Theory based on a photon transport model predicts that the threshold intensity for the stimulated cyclotron scattering is about 10 4 watts/cm 2 for the plasma parameters mentioned above. This value seems large also, but a longer wavelength of microwaves and a larger magnitude magnetic field, which will be the case in reactor type facilities, will lower the threshold intensity to levels comparable with the currently developed microwave sources

  1. Total absorption by degenerate critical coupling

    Energy Technology Data Exchange (ETDEWEB)

    Piper, Jessica R., E-mail: jrylan@stanford.edu; Liu, Victor; Fan, Shanhui, E-mail: shanhui@stanford.edu [Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2014-06-23

    We consider a mirror-symmetric resonator with two ports. We show that, when excited from a single port, complete absorption can be achieved through critical coupling to degenerate resonances with opposite symmetry. Moreover, any time two resonances with opposite symmetry are degenerate in frequency and absorption is always significantly enhanced. In contrast, when two resonances with the same symmetry are nearly degenerate, there is no absorption enhancement. We numerically demonstrate these effects using a graphene monolayer on top of a photonic crystal slab, illuminated from a single side in the near-infrared.

  2. Taking Stock.

    Science.gov (United States)

    Merriam, Sharan B.

    1993-01-01

    A complete theory of adult learning must take into consideration the learner, learning process, and context. Andragogy, self-directed learning, consciousness, critical theory, feminism, transformational learning, and situated cognition contribute to understanding of this complex phenomenon. (SK)

  3. Theory of the cancellation of 4-photon resonances by an off-resonance 3-photon cancellation

    DEFF Research Database (Denmark)

    Elk, M.; Lambropoulos, P.; Tang, X.

    1992-01-01

    We present a complete account of our recent work [Phys. Rev. A 44, 31 (1991)] in which we investigate the theory of cancellation by interference between the absorption of three fundamental laser photons and one third-harmonic photon. The theory is formulated in terms of the density matrix so...... as to take detunings, dephasing, and laser bandwidth into account. The result is a theory of cancellation for finite detuning that explains how four-photon resonances can be canceled by a three-photon mechanism if there is an atomic level at near-three-photon resonance. The treatment is extended to focused...

  4. Fano resonance in the absorption of two photons in crystal defects. Ressonancia de Fano na absorcao de dois fotons em defeitos cristalinos

    Energy Technology Data Exchange (ETDEWEB)

    Souza, G P

    1984-01-01

    The absorption of two photons in the electronic transition within the 4f/sup 7/ configuration which is superposed to the vibronic structure of the 4f/sup 7/ - 4f/sup 6/5d transition, is studied. The line shape with the Fano's formalism is described. The study was carried out on Eu/sup +2/ doped CaF/sub 2/. The experimental apparatus was built and the results obtained are in good agreement with the theoretical predictions.

  5. Calcium absorption

    International Nuclear Information System (INIS)

    Carlmark, B.; Reizenstein, P.; Dudley, R.A.

    1976-01-01

    The methods most commonly used to measure the absorption and retention of orally administered calcium are reviewed. Nearly all make use of calcium radioisotopes. The magnitude of calcium absorption and retention depends upon the chemical form and amount of calcium administered, and the clinical and nutritional status of the subject; these influences are briefly surveyed. (author)

  6. Absorption studies

    International Nuclear Information System (INIS)

    Ganatra, R.D.

    1992-01-01

    Absorption studies were once quite popular but hardly anyone does them these days. It is easier to estimate the blood level of the nutrient directly by radioimmunoassay (RIA). However, the information obtained by estimating the blood levels of the nutrients is not the same that can be obtained from the absorption studies. Absorption studies are primarily done to find out whether some of the essential nutrients are absorbed from the gut or not and if they are absorbed, to determine how much is being absorbed. In the advanced countries, these tests were mostly done to detect pernicious anaemia where vitamin B 12 is not absorbed because of the lack of the intrinsic factor in the stomach. In the tropical countries, ''malabsorption syndrome'' is quire common. In this condition, several nutrients like fat, folic acid and vitamin B 12 are not absorbed. It is possible to study absorption of these nutrients by radioisotopic absorption studies

  7. On the contradiction between the microscopic and integral data for fast neutron absorption cross-section for 238U nuclei

    International Nuclear Information System (INIS)

    Van'kov, A.A.

    1994-01-01

    The contradiction between a measured integral neutron absorption cross-section averaged over a fast reactor spectrum and the corresponding value which was calculated with the use of evaluated microscopic cross-sections and a theoretical neutron spectrum has been investigated. The possible systematic error of a correction factor which takes into account multiple resonance neutron scattering in samples used in the measurement of the absorption cross-section is investigated. It is proposed that this error may be one of the main reason for the contradiction mentioned above which arises in the measurement of the 236 U neutron absorption cross-section. (author). 13 refs, 3 figs

  8. Lifetime-broadening-suppressed X-ray absorption spectrum of β-YbAlB4 deduced from Yb 3d → 2p resonant X-ray emission spectroscopy

    International Nuclear Information System (INIS)

    Kawamura, Naomi; Mizumaki, Masaichiro; Kanai, Noriko; Hayashi, Hisashi; Matsuda, Yasuhiro H.; Kuga, Kentaro; Nakatsuji, Satoru; Watanabe, Shinji

    2017-01-01

    In this work, the Yb 3d → 2p (Yb Lα 1,2 ) resonant X-ray emission spectrum of β-YbAlB 4 was acquired using excitation energies around the Yb L 3 -edge, at 2 K. Subsequently, the lifetime-broadening-suppressed (LBS) X-ray absorption structure (XAS) spectrum was obtained using the SIM-RIXS program. This spectrum was found to exhibit clearly resolved pre-edge and shoulder structures. Resonant Lα 1 emission spectra were well reproduced from LBS-XAS profiles over wide ranges of excitation and emission energies. In contrast, noticeable discrepancies appeared between the experimental and simulated Lα 2 emission spectra, suggesting an effect resulting from M 4 M 5 O 1 Coster-Kronig transitions. LBS-XAS, in conjunction with partial fluorescence yield (PFY) XAS and transmission XAS, determined a value for the Yb valence (v) in β-YbAlB 4 of 2.76 ± 0.08 at 2 K. Despite this relatively large uncertainty in v, each method provided a consistent variation in valence (δv) as the temperature was raised from 2 to 280 K: 0.060 ± 0.004 (LBS-XAS), 0.061 ± 0.005 (PFY-XAS) and 0.058 ± 0.007 (transmission XAS). The smaller δv associated with LBS-XAS demonstrates the greater precision of this method. (author)

  9. Multiphotonic resonance processes in potassium vapor

    International Nuclear Information System (INIS)

    Bensoussan, Paul.

    1975-01-01

    Despite several theoretical and experimental investigations, the phenomena of resonance multiphotonic ionization are still not completely understood. The following lines of investigation were undertaken to try and elucidate certain aspects of the resonance processes. The first line of investigation aims at finding the processes which can compete with ionization. Resonance ionization processes can be considered as taking place in two stages: absorption induced excitation of a bound state, followed by photoionization from the excited level. The problem is now to determine what are the processes which compete with the ionization processes starting from a level selectively populated by the absorption of one or two photons. The second line aims at finding the influence of the polarization of the radiation on resonance multiphotonic ionization for the second photon and to check the validity of the selection rules on the magnetic quantic number of the resonance bound linked states. The last study therefore relates to the development of a method of multiphotonic spectrometry which could determine the energy levels in the alcaline f series [fr

  10. Folate absorption

    International Nuclear Information System (INIS)

    Baker, S.J.

    1976-01-01

    Folate is the generic term given to numerous compounds of pteroic acid with glutamic acid. Knowledge of absorption is limited because of the complexities introduced by the variety of compounds and because of the inadequacy of investigational methods. Two assay methods are in use, namely microbiological and radioactive. Techniques used to study absorption include measurement of urinary excretion, serum concentration, faecal excretion, intestinal perfusion, and haematological response. It is probably necessary to test absorption of both pteroylmonoglutamic acid and one or more polyglutamates, and such tests would be facilitated by availability of synthesized compounds labelled with radioactive tracers at specifically selected sites. (author)

  11. Wave energy extraction by coupled resonant absorbers.

    Science.gov (United States)

    Evans, D V; Porter, R

    2012-01-28

    In this article, a range of problems and theories will be introduced that will build towards a new wave energy converter (WEC) concept, with the acronym 'ROTA' standing for resonant over-topping absorber. First, classical results for wave power absorption for WECs constrained to operate in a single degree of freedom will be reviewed and the role of resonance in their operation highlighted. Emphasis will then be placed on how the introduction of further resonances can improve power take-off characteristics by extending the range of frequencies over which the efficiency is close to a theoretical maximum. Methods for doing this in different types of WECs will be demonstrated. Coupled resonant absorbers achieve this by connecting a WEC device equipped with its own resonance (determined from a hydrodynamic analysis) to a new system having separate mass/spring/damper characteristics. It is shown that a coupled resonant effect can be realized by inserting a water tank into a WEC, and this idea forms the basis of the ROTA device. In essence, the idea is to exploit the coupling between the natural sloshing frequencies of the water in the internal tank and the natural resonance of a submerged buoyant circular cylinder device that is tethered to the sea floor, allowing a rotary motion about its axis of attachment.

  12. The detailed balance requirement and general empirical formalisms for continuum absorption

    Science.gov (United States)

    Ma, Q.; Tipping, R. H.

    1994-01-01

    Two general empirical formalisms are presented for the spectral density which take into account the deviations from the Lorentz line shape in the wing regions of resonance lines. These formalisms satisfy the detailed balance requirement. Empirical line shape functions, which are essential to provide the continuum absorption at different temperatures in various frequency regions for atmospheric transmission codes, can be obtained by fitting to experimental data.

  13. Narrative absorption

    DEFF Research Database (Denmark)

    Narrative Absorption brings together research from the social sciences and Humanities to solve a number of mysteries: Most of us will have had those moments, of being totally absorbed in a book, a movie, or computer game. Typically we do not have any idea about how we ended up in such a state. No...

  14. Magnetodynamical resonance near the low-temperature phase transition in ErFeO3

    International Nuclear Information System (INIS)

    Dan'shin, N.K.; Kovtun, N.M.; Sdvizhkov, M.A.

    1986-01-01

    Magnetodynamical resonance (MDR) near low-temperature phase transition (PT) in erbium ortoferrite is investigated. At temperature below 4K (PT temperature) pt can be induced by a magnetic field. It is revealed that PT is accompained by partialsoftening of one of the magnetic resonance MR) branches. Besides MR soft mode resonance absorption was observed. This absorption is shown to be related to the excitation in a sample of dielectric resonance (DR). Essential differences of MDR near PT in ErFeO 3 are as follows: interaction between MR abd DR at PT takes place under softening of all interacting models; ErFeO 3 is characterized by a high value of permittivity epslon and by considerable anisotropy epsilon and magnetic permeability

  15. K- and L-edge X-ray Absorption Spectroscopy (XAS) and Resonant Inelastic X-ray Scattering (RIXS) Determination of Differential Orbital Covalency (DOC) of Transition Metal Sites.

    Science.gov (United States)

    Baker, Michael L; Mara, Michael W; Yan, James J; Hodgson, Keith O; Hedman, Britt; Solomon, Edward I

    2017-08-15

    Continual advancements in the development of synchrotron radiation sources have resulted in X-ray based spectroscopic techniques capable of probing the electronic and structural properties of numerous systems. This review gives an overview of the application of metal K-edge and L-edge X-ray absorption spectroscopy (XAS), as well as K resonant inelastic X-ray scattering (RIXS), to the study of electronic structure in transition metal sites with emphasis on experimentally quantifying 3d orbital covalency. The specific sensitivities of K-edge XAS, L-edge XAS, and RIXS are discussed emphasizing the complementary nature of the methods. L-edge XAS and RIXS are sensitive to mixing between 3d orbitals and ligand valence orbitals, and to the differential orbital covalency (DOC), that is, the difference in the covalencies for different symmetry sets of the d orbitals. Both L-edge XAS and RIXS are highly sensitive to and enable separation of and donor bonding and back bonding contributions to bonding. Applying ligand field multiplet simulations, including charge transfer via valence bond configuration interactions, DOC can be obtained for direct comparison with density functional theory calculations and to understand chemical trends. The application of RIXS as a probe of frontier molecular orbitals in a heme enzyme demonstrates the potential of this method for the study of metal sites in highly covalent coordination sites in bioinorganic chemistry.

  16. A subroutine for the calculation of resonance cross sections of U-238 in HTR fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Cuniberti, R; Marullo, G C

    1971-02-15

    In this paper, a survey of the codes used at Ispra for the calculations of resonance absorption in HTR fuel elements is presented and a subroutine for the calculation of resonance cross-sections, in a seven groups energy structure, for a HTR lattice of annular type is described. A library of homogeneous resonance integrals and a wide tabulation of lump and kernel Bell factors, and moderators efficiency is given. This paper deals mainly with the problem of taking into account the correct slowing down of neutrons in the graphite and with the derivation of Bell factors to be used in a multigroup calculation scheme.

  17. Absorptive products

    International Nuclear Information System (INIS)

    Assarsson, P.G.; King, P.A.

    1976-01-01

    Applications for hydrophile gels produced by the radiation induced cross-linking in aqueous solution of polyethylene oxide and starch, as described in Norwegian patent 133501 (INIS RN 281494), such as sanitary napkins (diapers) and sanitary towels, are discussed. The process itself is also discussed and results, expressed as the percentage of insoluble gel and its absorptive capacity for saline solution as functions of the ratio of polyethylene oxide to starch and the radiation dose, are presented. (JIW)

  18. An improved intermediate resonance method for heterogeneous media

    International Nuclear Information System (INIS)

    Chiovato, O.; Corno, S.; Pasquantonio, F.Di.

    1977-01-01

    A new formulation is described of the Intermediate Resonance method which incorporates the previous developments suitably modified and improved, together with some new contributions. The 'intermediate' character is directly introduced in the integral operator K, allowing a more rigorous deduction of the equations for evaluating the intermediate parameters related to the nuclides involved in the system. There is no limit to the number of internal (admixed in the fuel) and external moderators. The capability to take into account the interference scattering has been extended to heterogeneous systems. The Doppler broadening is described by means of new accurate rational approximations to the broadened line shape psi. Finally the use of energy mean values suitably defined refines the values of the resonance integrals and resonance absorption cross sections. The Intermediate Resonance method so extended and improved, has been coded in a group of FORTRAN routines, which have been inserted as a calculation option in the fast section of the GGC code for the evaluation of multigroup cross sections. A series of calculations has been carried out, using these routines, and comparisons have been made with Monte Carlo and Nordheim's methods. The results obtained show that the Intermediate Resonance method developed in the present work offers considerable advantages over Nordheim's method: better accuracy in evaluating resonance absorption cross sections, and much smaller computing times. (author)

  19. Temperature dependence of the hydrated electron's excited-state relaxation. I. Simulation predictions of resonance Raman and pump-probe transient absorption spectra of cavity and non-cavity models

    Science.gov (United States)

    Zho, Chen-Chen; Farr, Erik P.; Glover, William J.; Schwartz, Benjamin J.

    2017-08-01

    We use one-electron non-adiabatic mixed quantum/classical simulations to explore the temperature dependence of both the ground-state structure and the excited-state relaxation dynamics of the hydrated electron. We compare the results for both the traditional cavity picture and a more recent non-cavity model of the hydrated electron and make definite predictions for distinguishing between the different possible structural models in future experiments. We find that the traditional cavity model shows no temperature-dependent change in structure at constant density, leading to a predicted resonance Raman spectrum that is essentially temperature-independent. In contrast, the non-cavity model predicts a blue-shift in the hydrated electron's resonance Raman O-H stretch with increasing temperature. The lack of a temperature-dependent ground-state structural change of the cavity model also leads to a prediction of little change with temperature of both the excited-state lifetime and hot ground-state cooling time of the hydrated electron following photoexcitation. This is in sharp contrast to the predictions of the non-cavity model, where both the excited-state lifetime and hot ground-state cooling time are expected to decrease significantly with increasing temperature. These simulation-based predictions should be directly testable by the results of future time-resolved photoelectron spectroscopy experiments. Finally, the temperature-dependent differences in predicted excited-state lifetime and hot ground-state cooling time of the two models also lead to different predicted pump-probe transient absorption spectroscopy of the hydrated electron as a function of temperature. We perform such experiments and describe them in Paper II [E. P. Farr et al., J. Chem. Phys. 147, 074504 (2017)], and find changes in the excited-state lifetime and hot ground-state cooling time with temperature that match well with the predictions of the non-cavity model. In particular, the experiments

  20. Millimeter wave absorption by confined acoustic modes in CdSe/CdTe core-shell quantum dots

    International Nuclear Information System (INIS)

    Liu, T-M; Lu, J-Y; Kuo, C-C; Wen, Y-C; Lai, C-W; Yang, M-J; Chou, P-T; Murray, D B; Saviot, L; Sun, C-Kuang

    2007-01-01

    Taking advantage of the specific core-shell charge separation structure in the CdSe/CdTe core-shell Type-II quantum dots (QDs), we experimentally observed the resonant-enhanced dipolar interaction between millimeter-wave (MMW) photons and their corresponding (l = 1) confined acoustic phonons. With proper choice of size, the absorption band can be tuned to desired frequency of MMW imaging. Exploiting this characteristic absorption, in a fiber-scanned MMW imaging system, we demonstrated the feasibility of CdSe/CdTe QDs as the contrast agents of MMW imaging

  1. Absorption of electromagnetic field energy by superfluid system of atoms with electric dipole moment

    International Nuclear Information System (INIS)

    Poluektov, Yu.M.

    2014-01-01

    The modified Gross-Pitaevskii equation which takes into account relaxation and interaction with alternating electromagnetic field is used to consider the absorption of electromagnetic field energy by a superfluid system on the assumption that the atoms has intrinsic dipole moment. It is shown that the absorption may be of a resonant behavior only if the dispersion curves of the electromagnetic wave and the excitations of the superfluid system intersect. It is remarkable that such a situation is possible if the superfluid system has a branch of excitations with the energy gap at low momenta. The experiments on absorption of microwaves in superfluid helium are interpreted as evidence of existence of such gap excitations. A possible modification of the excitation spectrum of superfluid helium in the presence of excitation branch with energy gap is dis-cussed qualitatively

  2. Resonating Statements

    DEFF Research Database (Denmark)

    Hjelholt, Morten; Jensen, Tina Blegind

    2015-01-01

    IT projects are often complex arrangements of technological components, social actions, and organizational transformation that are difficult to manage in practice. This paper takes an analytical discourse perspective to explore the process of legitimizing IT projects. We introduce the concept...... of resonating statements to highlight how central actors navigate in various discourses over time. Particularly, the statements and actions of an IT project manager are portrayed to show how individuals can legitimize actions by connecting statements to historically produced discourses. The case study...... as part of a feedback loop to re-attach the localized IT project to the broader national discourse. The paper concludes with reflections on how to actively build on resonating statements as a strategic resource for legitimizing IT projects...

  3. Green’s function theory of ferromagnetic resonance in magnetic superlattices with damping

    International Nuclear Information System (INIS)

    Qiu, R.K.; Guo, F.F.; Zhang, Z.D.

    2016-01-01

    We explore a quantum Green’s-function method to study the resonance absorption of magnetic materials. The relationship between the resonance magnon (spin wave) density and the resonance frequency of a superlattice consisting of two magnetic layers with damping and antiferromagnetic interlayer exchange coupling is studied. The effects of temperature, interlayer coupling, anisotropy, external magnetic field and damping on the the resonance frequency and resonance magnon density are investigated. The resonance excitation probability for a magnon is proportional to the resonance magnon density. In the classic methods, the imaginary part of magnetic permeability represents the resonance absorption in magnetic materials. In the quantum approach, the resonance magnon density can be used to estimate the strength of the resonance absorption. In the present work, a quantum approach is developed to study resonance absorption of magnetic materials and the results show the method to obtain a magnetic multilayered materials with both high resonance frequency and high resonance absorption.

  4. Green’s function theory of ferromagnetic resonance in magnetic superlattices with damping

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, R.K., E-mail: rkqiu@163.com [Shenyang University of Technology, Shenyang 110870 (China); Guo, F.F. [Shenyang University of Technology, Shenyang 110870 (China); Zhang, Z.D. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2016-02-01

    We explore a quantum Green’s-function method to study the resonance absorption of magnetic materials. The relationship between the resonance magnon (spin wave) density and the resonance frequency of a superlattice consisting of two magnetic layers with damping and antiferromagnetic interlayer exchange coupling is studied. The effects of temperature, interlayer coupling, anisotropy, external magnetic field and damping on the the resonance frequency and resonance magnon density are investigated. The resonance excitation probability for a magnon is proportional to the resonance magnon density. In the classic methods, the imaginary part of magnetic permeability represents the resonance absorption in magnetic materials. In the quantum approach, the resonance magnon density can be used to estimate the strength of the resonance absorption. In the present work, a quantum approach is developed to study resonance absorption of magnetic materials and the results show the method to obtain a magnetic multilayered materials with both high resonance frequency and high resonance absorption.

  5. Unveiling the Microfoundations of Absorptive Capacity

    DEFF Research Database (Denmark)

    Distel, Andreas Philipp

    2017-01-01

    to absorptive capacity at the organizational level and that this relationship is mediated through a microlevel process. The findings reveal that knowledge workers’ cognitive process of perspective taking and their creative behavior are important microfoundations of absorptive capacity. Moreover, the results...... emphasize the critical role of key employees in explaining firm-level heterogeneity in building organizational capabilities....

  6. Dynamic nonlinear thermal optical effects in coupled ring resonators

    Directory of Open Access Journals (Sweden)

    Chenguang Huang

    2012-09-01

    Full Text Available We investigate the dynamic nonlinear thermal optical effects in a photonic system of two coupled ring resonators. A bus waveguide is used to couple light in and out of one of the coupled resonators. Based on the coupling from the bus to the resonator, the coupling between the resonators and the intrinsic loss of each individual resonator, the system transmission spectrum can be classified by three different categories: coupled-resonator-induced absorption, coupled-resonator-induced transparency and over coupled resonance splitting. Dynamic thermal optical effects due to linear absorption have been analyzed for each category as a function of the input power. The heat power in each resonator determines the thermal dynamics in this coupled resonator system. Multiple “shark fins” and power competition between resonators can be foreseen. Also, the nonlinear absorption induced thermal effects have been discussed.

  7. Interactions among resonances in the unresolved region

    International Nuclear Information System (INIS)

    Queiroz Bogado Leite, S. de.

    1982-11-01

    The theory on resonance absorption in the unresolved region is reviewed and a subroutine is presented, optional to UNRES in MC 2 code. Comparisons with the isolated resonance model suggest the necessity, in some cases, of considering interference and overlapping effects among resonances of the system. (Author) [pt

  8. Absorption of acoustic waves in La3Ga5SiO14 monocrystals

    International Nuclear Information System (INIS)

    Mansfel'd, G.D.; Bezdelkin, V.V.; Freik, A.D.; Kucheryavaya, E.S.

    1995-01-01

    Frequency dependences of longitudinal and transverse acoustic wave absorption coefficient in the basic crystallographic La 3 Ga 5 SiO 14 directions are measured by composite resonator method. The obtained values of absorption coefficient for all directions appear to be lower or approximately equal to the values of absorption coefficient in quartz monocrystals. Application of the resonator methods allows one to study factors affecting the resonator high-quality as well. 9 refs., 4 figs

  9. Measurement of resonance absorption integrals; Mesure des integrales de resonance d'absorption

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, R [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    The measurements are carried out by the pile oscillator technique, without cadmium filter., in a spectrum rich in epithermal neutrons. The values are extrapolated to infinite dilution and corrected for the junction function. For the excess on the part in l/V, the following values are found: In: 3200 {+-} 70 b; Hf: 2080 {+-} 50; Ag: 670 {+-} 20; Co: 50 {+-} 5; Cs: 450 {+-} 15; Th: 87 {+-} 4. (author) [French] Les mesures sont effectuees par la methode d'oscillation, sans filtre de cadmium, dans un spectre riche en neutrons epithermiques. Les valeurs sont extrapolees a la dilution infinie et corrigees de la fonction de jonction. On trouve, pour l'exces sur la partie en l/v: In: 3200 {+-} 70 b; Hf: 2080 {+-} 50; Ag: 670 {+-} 20; Co: 50 {+-} 5; Cs: 450 {+-} 15; Th: 87 {+-} 4. (auteur)

  10. Taking warfarin (Coumadin)

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000292.htm Taking warfarin (Coumadin) To use the sharing features on this ... form a clot or have bleeding problems. Taking Warfarin It is important that you take warfarin exactly ...

  11. Take Charge. Take the Test. PSA (:30)

    Centers for Disease Control (CDC) Podcasts

    As part of the Take Charge. Take the Test. campaign, this 30 second PSA encourages African American women to get tested for HIV. Locations for a free HIV test can be found by visiting hivtest.org/takecharge or calling 1-800-CDC-INFO (1-800-232-4636).

  12. Turbulent effective absorptivity and refractivity

    International Nuclear Information System (INIS)

    Rax, J.M.

    1984-09-01

    The problem of wave propagation in a turbulent magnetized plasma is investigated. Considering small scale, low frequency density fluctuations we solve the Maxwell equations and show that the eikonal approximation remains valid with an effective refractivity and an effective absorptivity taking into account the energy diffusion due to the turbulent motion. Then the result is applied to the problem of lower hybrid waves scattering by drift waves density fluctuations in tokamaks

  13. Identifying the perfect absorption of metamaterial absorbers

    Science.gov (United States)

    Duan, G.; Schalch, J.; Zhao, X.; Zhang, J.; Averitt, R. D.; Zhang, X.

    2018-01-01

    We present a detailed analysis of the conditions that result in unity absorption in metamaterial absorbers to guide the design and optimization of this important class of functional electromagnetic composites. Multilayer absorbers consisting of a metamaterial layer, dielectric spacer, and ground plane are specifically considered. Using interference theory, the dielectric spacer thickness and resonant frequency for unity absorption can be numerically determined from the functional dependence of the relative phase shift of the total reflection. Further, using transmission line theory in combination with interference theory we obtain analytical expressions for the unity absorption resonance frequency and corresponding spacer layer thickness in terms of the bare resonant frequency of the metamaterial layer and metallic and dielectric losses within the absorber structure. These simple expressions reveal a redshift of the unity absorption frequency with increasing loss that, in turn, necessitates an increase in the thickness of the dielectric spacer. The results of our analysis are experimentally confirmed by performing reflection-based terahertz time-domain spectroscopy on fabricated absorber structures covering a range of dielectric spacer thicknesses with careful control of the loss accomplished through water absorption in a semiporous polyimide dielectric spacer. Our findings can be widely applied to guide the design and optimization of the metamaterial absorbers and sensors.

  14. Implanted Silicon Resistor Layers for Efficient Terahertz Absorption

    Science.gov (United States)

    Chervenak, J. A.; Abrahams, J.; Allen, C. A.; Benford, D. J.; Henry, R.; Stevenson, T.; Wollack, E.; Moseley, S. H.

    2005-01-01

    Broadband absorption structures are an essential component of large format bolometer arrays for imaging GHz and THz radiation. We have measured electrical and optical properties of implanted silicon resistor layers designed to be suitable for these absorbers. Implanted resistors offer a low-film-stress, buried absorber that is robust to longterm aging, temperature, and subsequent metals processing. Such an absorber layer is readily integrated with superconducting integrated circuits and standard micromachining as demonstrated by the SCUBA II array built by ROE/NIST (1). We present a complete characterization of these layers, demonstrating frequency regimes in which different recipes will be suitable for absorbers. Single layer thin film coatings have been demonstrated as effective absorbers at certain wavelengths including semimetal (2,3), thin metal (4), and patterned metal films (5,6). Astronomical instrument examples include the SHARC II instrument is imaging the submillimeter band using passivated Bi semimetal films and the HAWC instrument for SOFIA, which employs ultrathin metal films to span 1-3 THz. Patterned metal films on spiderweb bolometers have also been proposed for broadband detection. In each case, the absorber structure matches the impedance of free space for optimal absorption in the detector configuration (typically 157 Ohms per square for high absorption with a single or 377 Ohms per square in a resonant cavity or quarter wave backshort). Resonant structures with -20% bandwidth coupled to bolometers are also under development; stacks of such structures may take advantage of instruments imaging over a wide band. Each technique may enable effective absorbers in imagers. However, thin films tend to age, degrade or change during further processing, can be difficult to reproduce, and often exhibit an intrinsic granularity that creates complicated frequency dependence at THz frequencies. Thick metal films are more robust but the requirement for

  15. Fundamentals of nanomechanical resonators

    CERN Document Server

    Schmid, Silvan; Roukes, Michael Lee

    2016-01-01

    This authoritative book introduces and summarizes the latest models and skills required to design and optimize nanomechanical resonators, taking a top-down approach that uses macroscopic formulas to model the devices. The authors cover the electrical and mechanical aspects of nano electromechanical system (NEMS) devices. The introduced mechanical models are also key to the understanding and optimization of nanomechanical resonators used e.g. in optomechanics. Five comprehensive chapters address: The eigenmodes derived for the most common continuum mechanical structures used as nanomechanical resonators; The main sources of energy loss in nanomechanical resonators; The responsiveness of micro and nanomechanical resonators to mass, forces, and temperature; The most common underlying physical transduction mechanisms; The measurement basics, including amplitude and frequency noise. The applied approach found in this book is appropriate for engineering students and researchers working with micro and nanomechanical...

  16. Take Charge. Take the Test. PSA (:30)

    Centers for Disease Control (CDC) Podcasts

    2012-03-07

    As part of the Take Charge. Take the Test. campaign, this 30 second PSA encourages African American women to get tested for HIV. Locations for a free HIV test can be found by visiting hivtest.org/takecharge or calling 1-800-CDC-INFO (1-800-232-4636).  Created: 3/7/2012 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 3/7/2012.

  17. Numerical study of surface plasmon enhanced nonlinear absorption and refraction.

    Science.gov (United States)

    Kohlgraf-Owens, Dana C; Kik, Pieter G

    2008-07-07

    Maxwell Garnett effective medium theory is used to study the influence of silver nanoparticle induced field enhancement on the nonlinear response of a Kerr-type nonlinear host. We show that the composite nonlinear absorption coefficient, beta(c), can be enhanced relative to the host nonlinear absorption coefficient near the surface plasmon resonance of silver nanoparticles. This enhancement is not due to a resonant enhancement of the host nonlinear absorption, but rather due to a phase shifted enhancement of the host nonlinear refractive response. The enhancement occurs at the expense of introducing linear absorption, alpha(c), which leads to an overall reduced figure of merit beta(c)/alpha(c) for nonlinear absorption. For thin (< 1 microm) composites, the use of surface plasmons is found to result in an increased nonlinear absorption response compared to that of the host material.

  18. Electrically Tunable Plasmonic Resonances with Graphene

    DEFF Research Database (Denmark)

    Emani, Naresh K.; Chung, Ting-Fung; Ni, Xingjie

    2012-01-01

    Real time switching of a plasmonic resonance may find numerous applications in subwavelength optoelectronics, spectroscopy and sensing. We take advantage of electrically tunable interband transitions in graphene to control the strength of the plasmonic resonance.......Real time switching of a plasmonic resonance may find numerous applications in subwavelength optoelectronics, spectroscopy and sensing. We take advantage of electrically tunable interband transitions in graphene to control the strength of the plasmonic resonance....

  19. Controlling coulomb interactions in infrared stereometamaterials for unity light absorption

    Science.gov (United States)

    Mudachathi, Renilkumar; Moritake, Yuto; Tanaka, Takuo

    2018-05-01

    We investigate the influence of near field interactions between the constituent 3D split ring resonators on the absorbance and resonance frequency of a stereo metamaterial based perfect light absorber. The experimental and theoretical analyses reveal that the magnetic resonance red shifts and broadens for both the decreasing vertical and lateral separations of the constituents within the metamaterial lattice, analogous to plasmon hybridization. The strong interparticle interactions for higher density reduce the effective cross-section per resonator, which results in weak light absorption observed in both experimental and theoretical analyses. The red shift of the magnetic resonance with increasing lattice density is an indication of the dominating electric dipole interactions and we analyzed the metamaterial system in an electrostatic point of view to explain the observed resonance shift and decreasing absorption peak. From these analyses, we found that the fill factor introduces two competing factors determining the absorption efficiency such as coulomb interactions between the constituent resonators and their number density in a given array structure. We predicted unity light absorption for a fill factor of 0.17 balancing these two opposing factors and demonstrate an experimental absorbance of 99.5% at resonance with our 3D device realized using residual stress induced bending of 2D patterns.

  20. Contributions to the developments in apollo 2 neutron transport code: 1) scattering kernel taking into account the thermal agitation, resonance effect on energy transfers - 2) criteria for the construction of a multigroup mesh

    International Nuclear Information System (INIS)

    Ouisloumen, M.

    1989-03-01

    This research thesis reports an investigation of neutron diffusion by the fuel of a nuclear reactor while taking thermal agitation of diffusing nuclei into account. The author adopted the free gas model to describe the atom vibrations in the crystal network. He reports the elaboration of a diffusion law which gives the neutron energy spectrum after collision. Some particular theoretical cases are then studied in order to explain the observed physical phenomena, and to confirm the obtained results. The Monte Carlo method is also used to validate these results. The author presents the various physical criteria which must be met by an energetic grid in order to minimize errors in reaction rate calculations

  1. D-xylose absorption

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003606.htm D-xylose absorption To use the sharing features on this page, please enable JavaScript. D-xylose absorption is a laboratory test to determine ...

  2. Absorption of controlled-release iron

    International Nuclear Information System (INIS)

    Cook, J.D.; Lipschitz, D.A.; Skikne, B.S.

    1982-01-01

    A multiple-dose double radioiron technic was used to compare absorption of iron administered as a controlled release (CR) capsule and as an elixir; both formulations contained 50 mg elemental iron as ferrous sulfate. When taken by normal subjects in the fasting state, mean absorption from the elixir and CR capsule averaged 4.92% and 4.38%, which gave a CR capsule:elixir ratio of 0.89. This difference was not significant, but when taken with meals that inhibit absorption of dietary iron by different degrees, absorption of the CR formulation was superior. CR capsule:elixir absorption ratios averaged 1.70 from a meal that is mildly inhibitory and 3.13 from a meal that causes more marked inhibition. It is concluded that CR iron formulations may offer a therapeutic advantage to patients who take oral iron with meals to avoid gastrointestinal side effects

  3. Taking iron supplements

    Science.gov (United States)

    ... medlineplus.gov/ency/article/007478.htm Taking iron supplements To use the sharing features on this page, ... levels. You may also need to take iron supplements as well to rebuild iron stores in your ...

  4. Absorption and excretion tests

    International Nuclear Information System (INIS)

    Berberich, R.

    1988-01-01

    The absorption and excretion of radiopharmaceuticals is still of interest in diagnostic investigations of nuclear medicine. In this paper the most common methods of measuring absorption and excretion are described. The performance of the different tests and their standard values are discussed. More over the basic possibilities of measuring absorption and excretion including the needed measurement equipments are presented. (orig.) [de

  5. Threshold nonlinear absorption in Zeeman transitions

    International Nuclear Information System (INIS)

    Narayanan, Andal; Hazra, Abheera; Sandhya, S N

    2010-01-01

    We experimentally study the absorption spectroscopy from a collection of gaseous 87 Rb atoms at room temperature irradiated with three fields. Two of these fields are in a pump-probe saturation absorption configuration. The third field co-propagates with the pump field. The three fields address Zeeman degenerate transitions between hyperfine levels 5S 1/2 , F = 1 and 5P 3/2 , F = 0, F = 1 around the D2 line. We find a sub-natural absorption resonance in the counter-propagating probe field for equal detunings of all three fields. This absorption arises in conjunction with the appearance of increased transmission due to electro-magnetically induced transparency in the co-propagating fields. The novel feature of this absorption is its onset only for the blue of 5P 3/2 , F = 0, as the laser frequency is scanned through the excited states 5P 3/2 , F = 0, F = 1 and F = 2. The absorption rapidly rises to near maximum values within a narrow band of frequency near 5P 3/2 , F = 0. Our experimental results are compared with a dressed atom model. We find the threshold absorption to be a result of coherent interaction between the dressed states of our system.

  6. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Recker, R.R.

    1985-01-01

    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement

  7. Mixed alkali effect in borate glasses - electron paramagnetic resonance and optical absorption studies in Cu sup 2 sup + doped xNa sub 2 O- (30 - x)K sub 2 O- 70B sub 2 O sub 3 glasses

    CERN Document Server

    Chakradhar, R P S; Rao, J L; Ramakrishna, J

    2003-01-01

    The mixed alkali borate glasses xNa sub 2 O-(30 - x)K sub 2 O-70B sub 2 O sub 3 (5 sup sup 2 B sub 2 sub g) and a weak band on the higher energy side at 22 115 cm sup - sup 1 corresponding to the transition ( sup 2 B sub 1 sub g -> sup 2 E sub g). With x > 5, the higher energy band disappears and the lower energy band shifts slightly to the lower energy side. By correlating the EPR and optical absorption data, the molecular orbital coefficients alpha sup 2 and beta sub 1 sup 2 are evaluated for the different glasses investigated. The values indicate that the in-plane sigma bonding is moderately covalent while the in-plane pi bonding is significantly ionic in nature; these exhibit a minimum with x = 15, showing the MAE. The theoretical values of optical basicity of the glasses have also been evaluated. From optical absorption edges, the optical bandgap energies have been calculated and are found to lie in the range 3.00-3.40 eV. The physical properties of the glasses studied have also been evaluated with respe...

  8. The Resonance Integral of Gold

    Energy Technology Data Exchange (ETDEWEB)

    Jirlow, K; Johansson, E

    1959-04-15

    The resonance activation integral of gold has been determined, by means of cadmium ratio measurements of thin foils in a neutron beam. Comparison was made with a 1/v detector, and the neutron spectra were measured with a chopper. The resonance integral, RI, is defined as {integral}{sub 0.5}{sup {infinity}}{sigma}{sub r}(E)dE/E, where {sigma}{sub r}(E) is the differenc between the total absorption cross section and the 1/v part. An experimental value of 1490 {+-} 40 barns has been obtained. RI has also been computed from resonance parameter data with the result 1529 {+-} 70 barns.

  9. Light absorption and scattering mechanisms in laser fusion plasmas

    International Nuclear Information System (INIS)

    Barnes, C.; Estabrook, K.G.; Kruer, W.L.; Langdon, A.B.; Lasinski, B.F.; Max, C.E.; Randall, C.; Thomson, J.J.

    1977-01-01

    The picture of laser light absorption and scattering which is emerging from theory and computer simulation studies of laser-plasma interactions is described. On the subject of absorption, we discuss theoretical and experimental evidence that resonance absorption in a steepened density profile is a dominant absorption mechanism. Recent work also indicates the presence of critical surface ripples, which we study using two and three dimensional computer simulations. Predictions of hot electron spectra due to resonance absorption are described, as are effects of plasma outflow. We then discuss two regimes where stimulated scattering may occur. Brillouin scattering is expected in the underdense target blow-off, for long laser pulses, and is limited by ion heating. Raman scattering in the background gas of a reactor target chamber is predicted to be at most a 10 percent effect for 1 μm lasers

  10. Cyclotron resonance for electrons over helium in resonator

    CERN Document Server

    Shikin, V B

    2002-01-01

    The problem on the cyclotron resonance (CR) for electrons on the helium film, positioned in the resonator lower part, is solved. It is shown, that it relates to one of the examples of the known problem on the oscillations of the coupled oscillators system. The coupling constant between these oscillators constituting the variable function of the problem parameters. It is minimal in the zero magnetic field and reaches its maximum under the resonance conditions, when the cyclotron frequency coincides with one of the resonator modes. The CR details of the Uhf CR-energy absorption coupled by the electrons + resonator system, are calculated. The applications of the obtained results to the available CR experiments for electrons over helium

  11. Absorption of electromagnetic radiation in a quantum wire with an anisotropic parabolic potential in a transverse magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Karpunin, V. V., E-mail: karpuninvv@mail.ru [Mordovian State Pedagogical Institute (Russian Federation); Margulis, V. A., E-mail: theorphysics@mrsu.ru [Mordovian State University (Russian Federation)

    2016-06-15

    An analytical expression for the coefficient of absorption of electromagnetic radiation by electrons in a quantum wire in a magnetic field is derived. The case of a magnetic field transverse with respect to the wire axis is considered. The resonance character of absorption is shown, and the resonance frequencies as functions of the field are determined. The effect of the scattering of electrons at optical phonons is studied, and it is shown that scattering is responsible for additional resonance absorption peaks.

  12. Multiphoton resonances

    International Nuclear Information System (INIS)

    Shore, B.W.

    1977-01-01

    The long-time average of level populations in a coherently-excited anharmonic sequence of energy levels (e.g., an anharmonic oscillator) exhibits sharp resonances as a function of laser frequency. For simple linearly-increasing anharmonicity, each resonance is a superposition of various multiphoton resonances (e.g., a superposition of 3, 5, 7, . . . photon resonances), each having its own characteristic width predictable from perturbation theory

  13. [Study on lead absorption in pumpkin by atomic absorption spectrophotometry].

    Science.gov (United States)

    Li, Zhen-Xia; Sun, Yong-Dong; Chen, Bi-Hua; Li, Xin-Zheng

    2008-07-01

    A study was carried out on the characteristic of lead absorption in pumpkin via atomic absorption spectrophotometer. The results showed that lead absorption amount in pumpkin increased with time, but the absorption rate decreased with time; And the lead absorption amount reached the peak in pH 7. Lead and cadmium have similar characteristic of absorption in pumpkin.

  14. Microwave Absorption Characteristics of Tire

    Science.gov (United States)

    Zhang, Yuzhe; Hwang, Jiann-Yang; Peng, Zhiwei; Andriese, Matthew; Li, Bowen; Huang, Xiaodi; Wang, Xinli

    The recycling of waste tires has been a big environmental problem. About 280 million waste tires are produced annually in the United States and more than 2 billion tires are stockpiled, which cause fire hazards and health issues. Tire rubbers are insoluble elastic high polymer materials. They are not biodegradable and may take hundreds of years to decompose in the natural environment. Microwave irradiation can be a thermal processing method for the decomposition of tire rubbers. In this study, the microwave absorption properties of waste tire at various temperatures are characterized to determine the conditions favorable for the microwave heating of waste tires.

  15. Determination of space-energy distribution of resonance neutrons in reactor lattice cell and calculation of resonance integrals

    International Nuclear Information System (INIS)

    Zmijarevic, I.

    1980-01-01

    Space-energy distribution of resonance neutrons in reactor lattice cell was determined by solving the Boltzmann equation by spherical harmonics method applying P-3 approximation. Computer code SPLET used for these calculations is described. Resonance absorption and calculation of resonance integrals are described as well. Effective resonance integral values for U-238 resonance at 6.7 Ev are calculated for heavy water reactor cell with metal, oxide and carbide fuel elements

  16. Resonant Auger studies of metallic systems

    International Nuclear Information System (INIS)

    Coulthard, I.; Antel, W. J. Jr.; Frigo, S. P.; Freeland, J. W.; Moore, J.; Calaway, W. S.; Pellin, M. J.; Mendelsohn, M.; Sham, T. K.; Naftel, S. J.

    2000-01-01

    Results of resonant Auger spectroscopy experimental are presented for Cu, Co, and oxidized Al. Sublifetime narrowing of Auger spectra and generation of sublifetime narrowed absorption spectra constructed from Auger yield measurements were observed. Resonant Auger yields are used to identify three chemical states of oxidized Al. Partial absorption yield spectra were derived giving detailed electronic information and thickness information for the various chemical states of the bulk metal, the passivating aluminum oxide layer, and the metal-oxide interface region. In addition, the total absorption yield spectrum for the oxidized Al sample was constructed from the partial yield data, supporting the consistency of our method. (c) 2000 American Vacuum Society

  17. Absorption heat pumps

    International Nuclear Information System (INIS)

    Formigoni, C.

    1998-01-01

    A brief description of the difference between a compression and an absorption heat pump is made, and the reasons why absorption systems have spread lately are given. Studies and projects recently started in the field of absorption heat pumps, as well as criteria usually followed in project development are described. An outline (performance targets, basic components) of a project on a water/air absorption heat pump, running on natural gas or LPG, is given. The project was developed by the Robur Group as an evolution of a water absorption refrigerator operating with a water/ammonia solution, which has been on the market for a long time and recently innovated. Finally, a list of the main energy and cost advantages deriving from the use of absorption heat pumps is made [it

  18. Resonance gamma-transducer with thin converter

    International Nuclear Information System (INIS)

    Mirzababaev, R.M.

    1993-01-01

    A resonance detector with stainless steel foil (∼3000 A) is more efficient than conventional detectors as regards the recording Rayleigh scattering of Moessbauer effect. If the scatterer contains resonance nuclei (iron), the detector simultaneously records in the same spectrum both Zeeman lines and the line resulted to Rayleigh quanta scattering on electrons. Zeeman lines are formed due to photoabsorption in the converter. The central line is associated with resonance absorption in the converter

  19. Multiphoton Absorption Order of CsPbBr3 As Determined by Wavelength-Dependent Nonlinear Optical Spectroscopy.

    Science.gov (United States)

    Saouma, Felix O; Stoumpos, Constantinos C; Kanatzidis, Mercouri G; Kim, Yong Soo; Jang, Joon I

    2017-10-05

    CsPbBr 3 is a direct-gap semiconductor where optical absorption takes place across the fundamental bandgap, but this all-inorganic halide perovskite typically exhibits above-bandgap emission when excited over an energy level, lying above the conduction-band minimum. We probe this bandgap anomaly using wavelength-dependent multiphoton absorption spectroscopy and find that the fundamental gap is strictly two-photon forbidden, rendering it three-photon absorption (3PA) active. Instead, two-photon absorption (2PA) commences when the two-photon energy is resonant with the optical gap, associated with the level causing the anomaly. We determine absolute nonlinear optical dispersion over this 3PA-2PA region, which can be explained by two-band models in terms of the optical gap. The polarization dependence of 3PA and 2PA is also measured and explained by the relevant selection rules. CsPbBr 3 is highly luminescent under multiphoton absorption at room temperature with marked polarization and wavelength dependence at the 3PA-2PA crossover and therefore has potential for nonlinear optical applications.

  20. Nucleon multiplicities after pion absorption in 160

    International Nuclear Information System (INIS)

    Hamers, R.

    1989-01-01

    The experiment described in this thesis concerns a simultaneous measurement of two- and higher-fold coincidences following positive and negative pion absorption in 16 0. The detected particles are protons, neutrons and deuterons. The detection and analysis of charged particles is discussed. The incident pion energy was 65 MeV, thus well below the delta resonance. The low pion energy was 65 MeV, thus well below the delta resonance. The low pion energy ensures that contributions of initial state interactions, i.e. pion-nucleon scattering preceding absorption, are minimized. The following reaction channels were selected and analyzed: π + ,pp), (π + ,pd). Evidence for quasifree reaction precessed has been investigated by comparing the data with phase-space calculations incorporating the geometry of the experimental setup. (author). 36 refs.; 1 figs.; 3 tabs

  1. How to take statins

    Science.gov (United States)

    ... allergies. You are taking other medicines. You have diabetes. You have liver disease. You should not take statins if you ... with your provider about the possible risks for: Liver damage Severe ... High blood sugar, or type 2 diabetes Memory loss Confusion

  2. Note Taking and Recall

    Science.gov (United States)

    Fisher, Judith L.; Harris, Mary B.

    1974-01-01

    To study the effect of note taking and opportunity for review on subsequent recall, 88 college students were randomly assigned to five treatment groups utilizing different note taking and review combinations. No treatment effects were found, although quality of notes was positively correlated with free recall an multiple-choice measures.…

  3. Resonant detector of γ-quanta with thin converter

    International Nuclear Information System (INIS)

    Mirzababaev, R.M.

    1994-01-01

    A resonant detector with a converter made from an enriched stainless-steel foil about 3000 angstrom thick is more efficient in detecting spectra of Rayleigh-scattered γ-quanta than conventional detectors. If the scatterer contains resonant nuclei (iron), both Zeeman lines and lines due to Rayleigh scattering by electrons are detected in the same spectrum. Zeeman lines are due to γ-radiation absorption in the converter, while the central line is due to resonant absorption in the converter

  4. Optical absorption of carbon-gold core-shell nanoparticles

    Science.gov (United States)

    Wang, Zhaolong; Quan, Xiaojun; Zhang, Zhuomin; Cheng, Ping

    2018-01-01

    In order to enhance the solar thermal energy conversion efficiency, we propose to use carbon-gold core-shell nanoparticles dispersed in liquid water. This work demonstrates theoretically that an absorbing carbon (C) core enclosed in a plasmonic gold (Au) nanoshell can enhance the absorption peak while broadening the absorption band; giving rise to a much higher solar absorption than most previously studied core-shell combinations. The exact Mie solution is used to evaluate the absorption efficiency factor of spherical nanoparticles in the wavelength region from 300 nm to 1100 nm as well as the electric field and power dissipation profiles inside the nanoparticles at specified wavelengths (mostly at the localized surface plasmon resonance wavelength). The field enhancement by the localized plasmons at the gold surfaces boosts the absorption of the carbon particle, resulting in a redshift of the absorption peak with increased peak height and bandwidth. In addition to spherical nanoparticles, we use the finite-difference time-domain method to calculate the absorption of cubic core-shell nanoparticles. Even stronger enhancement can be achieved with cubic C-Au core-shell structures due to the localized plasmonic resonances at the sharp edges of the Au shell. The solar absorption efficiency factor can exceed 1.5 in the spherical case and reach 2.3 in the cubic case with a shell thickness of 10 nm. Such broadband absorption enhancement is in great demand for solar thermal applications including steam generation.

  5. Resonance shielding in thermal reactor lattices

    International Nuclear Information System (INIS)

    Rothenstein, W.; Taviv, E.; Aminpour, M.

    1982-01-01

    The theoretical foundations of a new methodology for the accurate treatment of resonance absorption in thermal reactor lattice analysis are presented. This methodology is based on the solution of the point-energy transport equation in its integral or integro-differential form for a heterogeneous lattice using detailed resonance cross-section profiles. The methodology is applied to LWR benchmark analysis, with emphasis on temperature dependence of resonance absorption during fuel depletion, spatial and mutual self-shielding, integral parameter analysis and treatment of cluster geometry. The capabilities of the OZMA code, which implements the new methodology are discussed. These capabilities provide a means against which simpler and more rapid resonance absorption algorithms can be checked. (author)

  6. Tunable electromagnetically induced absorption based on graphene

    Science.gov (United States)

    Cao, Maoyong; Wang, Tongling; Zhang, Huiyun; Zhang, Yuping

    2018-04-01

    In this paper, an electronically induced absorption (EIA) structure based on graphene at the infrared frequency is proposed. A pair of nanorods is coupled to a ring resonator, resulting in electronically induced transparency (EIT), and then, Babinet's principle is applied to transform the EIT structure into an EIA structure. Based on the bright and dark modes of the coupling schemes, the adjustment of the coupling strength between the dark and bright modes can be achieved by changing the asymmetry degree. In addition, the transparency window and the absorption peak can be tuned by changing the Fermi energy of graphene. This graphene-based EIA structure can develop the path in narrow-band filtering and, absorptive switching in the future.

  7. Solar absorption surface panel

    Science.gov (United States)

    Santala, Teuvo J.

    1978-01-01

    A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

  8. Nutrition and magnesium absorption

    NARCIS (Netherlands)

    Brink, E.J.

    1992-01-01

    The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true

  9. Zeeman atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    Loos-Vollebregt, M.T.C. de.

    1980-01-01

    A new method of background correction in atomic absorption spectroscopy has recently been introduced, based on the Zeeman splitting of spectral lines in a magnetic field. A theoretical analysis of the background correction capability observed in such instruments is presented. A Zeeman atomic absorption spectrometer utilizing a 50 Hz sine wave modulated magnetic field is described. (Auth.)

  10. Determination of hafnium by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Yoshida, Isao; Kobayashi, Hiroshi; Ueno, Keihei.

    1977-01-01

    Optimum conditions for atomic absorption spectrophotometric determination of hafnium were investigated by use of a Jarrel-Ash AA-1 instrument which was equipped with a premixed gas burner slotted 50 mm in length and 0.4 mm in width. Absorption of hafnium, which was atomized in an nitrous oxide-acetylene flame, was measured on a resonance line at 307.29 nm. The absorption due to hafnium was enhanced in the presence of ammonium fluoride and iron(III) ion, as shown in Figs. 2 and 3, depending on their concentration. The highest absorption was attained by the addition of (0.15 -- 0.3)M ammonium fluoride, 0.07 M of iron(III) ion and 0.05 M of hydrochloric acid. An excess of the additives decreased the absorption. The presence of zirconium, which caused a significant interference in the ordinary analytical methods, did not affect the absorption due to hafnium, if the zirconium concentration is less than 0.2 M. A standard procedure was proposed; A sample containing a few mg of hafnium was dissolved in a 25-ml volumetric flask, and ammonium fluoride, ferric nitrate and hydrochloric acid were added so that the final concentrations were 0.3, 0.07 and 0.05 M, respectively. Atomic absorption was measured on the aqueous solution in a nitrous oxide-acetylene flame and the hafnium content was calculated from the absorbance. Sensitivity was as high as 12.5 μg of Hf/ml/l% absorption. The present method is especially recommendable to the direct determination of hafnium in samples containing zirconium. (auth.)

  11. 1. On note taking.

    Science.gov (United States)

    Plaut, Alfred B J

    2005-02-01

    In this paper the author explores the theoretical and technical issues relating to taking notes of analytic sessions, using an introspective approach. The paper discusses the lack of a consistent approach to note taking amongst analysts and sets out to demonstrate that systematic note taking can be helpful to the analyst. The author describes his discovery that an initial phase where as much data was recorded as possible did not prove to be reliably helpful in clinical work and initially actively interfered with recall in subsequent sessions. The impact of the nature of the analytic session itself and the focus of the analyst's interest on recall is discussed. The author then describes how he modified his note taking technique to classify information from sessions into four categories which enabled the analyst to select which information to record in notes. The characteristics of memory and its constructive nature are discussed in relation to the problems that arise in making accurate notes of analytic sessions.

  12. Role of screening and angular distributions in resonant soft-x-ray emission of CO

    Energy Technology Data Exchange (ETDEWEB)

    Skytt, P.; Glans, P.; Gunnelin, K. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    In the present work the authors focus on two particular properties of resonant X-ray emission, namely core hole screening of the excited electron, and anisotropy caused by the polarization of the exciting synchrotron radiation. The screening of the core hole by the excited electron causes energy shifts and intensity variations in resonant spectra compared to the non-resonant case. The linear polarization of the synchrotron radiation and the dipole nature of the absorption process create a preferential alignment selection of the randomly oriented molecules in the case of resonant excitation, producing an anisotropy in the angular distribution of the emitted X-rays. The authors have chosen CO for this study because this molecule has previously served as a showcase for non-resonant X-ray emission, mapping the valence electronic structure differently according to the local selection rules. With the present work they take interest in how this characteristic feature of the spectroscopy is represented in the resonant case.

  13. Stochastic resonance

    International Nuclear Information System (INIS)

    Wellens, Thomas; Shatokhin, Vyacheslav; Buchleitner, Andreas

    2004-01-01

    We are taught by conventional wisdom that the transmission and detection of signals is hindered by noise. However, during the last two decades, the paradigm of stochastic resonance (SR) proved this assertion wrong: indeed, addition of the appropriate amount of noise can boost a signal and hence facilitate its detection in a noisy environment. Due to its simplicity and robustness, SR has been implemented by mother nature on almost every scale, thus attracting interdisciplinary interest from physicists, geologists, engineers, biologists and medical doctors, who nowadays use it as an instrument for their specific purposes. At the present time, there exist a lot of diversified models of SR. Taking into account the progress achieved in both theoretical understanding and practical application of this phenomenon, we put the focus of the present review not on discussing in depth technical details of different models and approaches but rather on presenting a general and clear physical picture of SR on a pedagogical level. Particular emphasis will be given to the implementation of SR in generic quantum systems-an issue that has received limited attention in earlier review papers on the topic. The major part of our presentation relies on the two-state model of SR (or on simple variants thereof), which is general enough to exhibit the main features of SR and, in fact, covers many (if not most) of the examples of SR published so far. In order to highlight the diversity of the two-state model, we shall discuss several examples from such different fields as condensed matter, nonlinear and quantum optics and biophysics. Finally, we also discuss some situations that go beyond the generic SR scenario but are still characterized by a constructive role of noise

  14. Synchrobetatron resonances

    International Nuclear Information System (INIS)

    1977-03-01

    At the 1975 Particle Accelerator Conference it was reported that a class of resonances were observed in SPEAR II that had not appeared before in SPEAR I. While the existence of sideband resonances of the main betatron oscillation frequencies has been previously observed and analyzed, the resonances observed in SPEAR do not appear to be of the same variety. Experiments were performed at SPEAR to identify the mechanism believed to be the most likely explanation. Some of the current experimental knowledge and theoretical views on the source of these resonances are presented

  15. Snake resonances

    International Nuclear Information System (INIS)

    Tepikian, S.

    1988-01-01

    Siberian Snakes provide a practical means of obtaining polarized proton beams in large accelerators. The effect of snakes can be understood by studying the dynamics of spin precession in an accelerator with snakes and a single spin resonance. This leads to a new class of energy independent spin depolarizing resonances, called snake resonances. In designing a large accelerator with snakes to preserve the spin polarization, there is an added constraint on the choice of the vertical betatron tune due to the snake resonances. 11 refs., 4 figs

  16. Coherence Phenomena in Coupled Optical Resonators

    Science.gov (United States)

    Smith, D. D.; Chang, H.

    2004-01-01

    We predict a variety of photonic coherence phenomena in passive and active coupled ring resonators. Specifically, the effective dispersive and absorptive steady-state response of coupled resonators is derived, and used to determine the conditions for coupled-resonator-induced transparency and absorption, lasing without gain, and cooperative cavity emission. These effects rely on coherent photon trapping, in direct analogy with coherent population trapping phenomena in atomic systems. We also demonstrate that the coupled-mode equations are formally identical to the two-level atom Schrodinger equation in the rotating-wave approximation, and use this result for the analysis of coupled-resonator photon dynamics. Notably, because these effects are predicted directly from coupled-mode theory, they are not unique to atoms, but rather are fundamental to systems of coherently coupled resonators.

  17. Hybrid simulation of electron cyclotron resonance heating

    Energy Technology Data Exchange (ETDEWEB)

    Ropponen, T. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland)], E-mail: tommi.ropponen@phys.jyu.fi; Tarvainen, O. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Suominen, P. [CERN Geneve 23, CH-1211 (Switzerland); Koponen, T.K. [Department of Physics, University of Jyvaeskylae, Nanoscience Center, P.O. Box 35, FI-40014 (Finland); Kalvas, T.; Koivisto, H. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland)

    2008-03-11

    Electron Cyclotron Resonance (ECR) heating is a fundamentally important aspect in understanding the physics of Electron Cyclotron Resonance Ion Sources (ECRIS). Absorption of the radio frequency (RF) microwave power by electron heating in the resonance zone depends on many parameters including frequency and electric field strength of the microwave, magnetic field structure and electron and ion density profiles. ECR absorption has been studied in the past by e.g. modelling electric field behaviour in the resonance zone and its near proximity. This paper introduces a new ECR heating code that implements damping of the microwave power in the vicinity of the resonance zone, utilizes electron density profiles and uses right hand circularly polarized (RHCP) electromagnetic waves to simulate electron heating in ECRIS plasma.

  18. Magnetic resonance imaging

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    Magnetic resonance imaging (MRI) is a new and innovative technique that affords anatomic images in multiple planes and that may provide information about tissue characterization. The magnetic resonance images are obtained by placing the patient or the area of interest within a powerful, highly uniform, static magnetic field. Magnetized protons (hydrogen nuclei) within the patient align like small magnets in this field. Radiofrequency pulses are then used to create an oscillating magnetic field perpendicular to the main field. Magnetic resonance images differ from those produced by x-rays: the latter are associated with absorption of x-ray energy while magnetic resonance images are based on proton density and proton relaxation dynamics. Proton characteristics vary according to the tissue under examination and reflect its physical and chemical properties. To resolve issues regarding safety and efficacy, the Warren Grant Magnuson Clinical Center and the Office of Medical Applications of Research of the National Institutes of Health (NIH) convened a consensus conference about MRI Oct 26 through 28, 1987. At the NIH, the Consensus Development Conference brings together investigators in the biomedical sciences, clinical investigators, practicing physicians, and consumer and special interest groups to make a scientific assessment of technologies, including drugs, devices, and procedures, and to seek agreement on their safety and effectiveness

  19. Quasar Absorption Studies

    Science.gov (United States)

    Mushotzky, Richard (Technical Monitor); Elvis, Martin

    2004-01-01

    The aim of the proposal is to investigate the absorption properties of a sample of inter-mediate redshift quasars. The main goals of the project are: Measure the redshift and the column density of the X-ray absorbers; test the correlation between absorption and redshift suggested by ROSAT and ASCA data; constrain the absorber ionization status and metallicity; constrain the absorber dust content and composition through the comparison between the amount of X-ray absorption and optical dust extinction. Unanticipated low energy cut-offs where discovered in ROSAT spectra of quasars and confirmed by ASCA, BeppoSAX and Chandra. In most cases it was not possible to constrain adequately the redshift of the absorber from the X-ray data alone. Two possibilities remain open: a) absorption at the quasar redshift; and b) intervening absorption. The evidences in favour of intrinsic absorption are all indirect. Sensitive XMM observations can discriminate between these different scenarios. If the absorption is at the quasar redshift we can study whether the quasar environment evolves with the Cosmic time.

  20. Technique for magnetic susceptibility determination in the highly doped semiconductors by electron spin resonance

    Energy Technology Data Exchange (ETDEWEB)

    Veinger, A. I.; Zabrodskii, A. G.; Tisnek, T. V.; Goloshchapov, S. I.; Semenikhin, P. V. [Ioffe Institute of the Russian Academy of Sciences, St. Petersburg (Russian Federation)

    2014-08-20

    A method for determining the magnetic susceptibility in the highly doped semiconductors is considered. It is suitable for the semiconductors near the metal - insulator transition when the conductivity changes very quickly with the temperature and the resonance line form distorts. A procedure that is based on double integration of the positive part of the derivative of the absorption line having a Dyson shape and takes into account the depth of the skin layer is described. Analysis is made for the example of arsenic-doped germanium samples at a rather high concentration corresponding to the insulator-metal phase transition.

  1. Optical absorption of hyperbolic metamaterial with stochastic surfaces

    DEFF Research Database (Denmark)

    Liu, Jingjing; Naik, Gururaj V.; Ishii, Satoshi

    2014-01-01

    We investigate the absorption properties of planar hyperbolic metamaterials (HMMs) consisting of metal-dielectric multilayers, which support propagating plane waves with anomalously large wavevectors and high photonic-density-of-states over a broad bandwidth. An interface formed by depositing...... indium-tin-oxide nanoparticles on an HMM surface scatters light into the high-k propagating modes of the metamaterial and reduces reflection. We compare the reflection and absorption from an HMM with the nanoparticle cover layer versus those of a metal film with the same thickness also covered...... with the nanoparticles. It is predicted that the super absorption properties of HMM show up when exceedingly large amounts of high-k modes are excited by strong plasmonic resonances. In the case that the coupling interface is formed by non-resonance scatterers, there is almost the same enhancement in the absorption...

  2. Far-wing absorption in Na-Ar collision

    International Nuclear Information System (INIS)

    Kulander, K.C.

    1985-01-01

    Collision-induced absorption and emission at wavelengths well removed from line center play important roles in many atomic and molecular processes. The authors have developed the theory and computer codes to calculate exact quantum mechanical cross sections for these optical and radiative collisions between atoms. The authors also have produced a quasi-classical model that can efficiently generate accurate absorption cross sections. This model cannot, however, give branching ratios for the final-state populations. Their codes and model can be used to study the propagation of nearly resonant light through gaseous media and to calculate accurate gain and absorption cross sections for the far wings of atomic transitions. The authors have used their theory to study the collision-induced absorption by sodium in argon for wavelengths in the vicinity of the resonance lines D 1 and D 2

  3. Ly α Absorption at Transits of HD 209458b: A Comparative Study of Various Mechanisms Under Different Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Khodachenko, M. L.; Lammer, H.; Kislyakova, K. G.; Fossati, L.; Arkhypov, O. V. [Space Research Institute, Austrian Academy of Sciences, Graz (Austria); Shaikhislamov, I. F.; Berezutsky, A. G.; Miroshnichenko, I. B.; Posukh, V. G. [Institute of Laser Physics SB RAS, Novosibirsk (Russian Federation); Johnstone, C. P., E-mail: maxim.khodachenko@oeaw.ac.at [Department of Astrophysics, University of Vienna (Austria)

    2017-10-01

    To shed more light on the nature of the observed Ly α absorption during transits of HD 209458b and to quantify the major mechanisms responsible for the production of fast hydrogen atoms (the so-called energetic neutral atoms, ENAs) around the planet, 2D hydrodynamic multifluid modeling of the expanding planetary upper atmosphere, which is driven by stellar XUV, and its interaction with the stellar wind has been performed. The model self-consistently describes the escaping planetary wind, taking into account the generation of ENAs due to particle acceleration by the radiation pressure and by the charge exchange between the stellar wind protons and planetary atoms. The calculations in a wide range of stellar wind parameters and XUV flux values showed that under typical Sun-like star conditions, the amount of generated ENAs is too small, and the observed absorption at the level of 6%–8% can be attributed only to the non-resonant natural line broadening. For lower XUV fluxes, e.g., during the activity minima, the number of planetary atoms that survive photoionization and give rise to ENAs increases, resulting in up to 10%–15% absorption at the blue wing of the Ly α line, caused by resonant thermal line broadening. A similar asymmetric absorption can be seen under the conditions realized during coronal mass ejections, when sufficiently high stellar wind pressure confines the escaping planetary material within a kind of bowshock around the planet. It was found that the radiation pressure in all considered cases has a negligible contribution to the production of ENAs and the corresponding absorption.

  4. Uranium absorption study pile

    International Nuclear Information System (INIS)

    Raievski, V.; Sautiez, B.

    1959-01-01

    The report describes a pile designed to measure the absorption of fuel slugs. The pile is of graphite and comprises a central section composed of uranium rods in a regular lattice. RaBe sources and BF 3 counters are situated on either side of the center. A given uranium charge is compared with a specimen charge of about 560 kg, and the difference in absorption between the two noted. The sensitivity of the equipment will detect absorption variations of about a few ppm boron (10 -6 boron per gr. of uranium) or better. (author) [fr

  5. Optical Microspherical Resonators for Biomedical Sensing

    Directory of Open Access Journals (Sweden)

    Giancarlo C. Righini

    2011-01-01

    Full Text Available Optical resonators play an ubiquitous role in modern optics. A particular class of optical resonators is constituted by spherical dielectric structures, where optical rays are total internal reflected. Due to minimal reflection losses and to potentially very low material absorption, these guided modes, known as whispering gallery modes, can confer the resonator an exceptionally high quality factor Q, leading to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. These attractive characteristics make these miniaturized optical resonators especially suited as laser cavities and resonant filters, but also as very sensitive sensors. First, a brief analysis is presented of the characteristics of microspherical resonators, of their fabrication methods, and of the light coupling techniques. Then, we attempt to overview some of the recent advances in the development of microspherical biosensors, underlining a number of important applications in the biomedical field.

  6. Nonlinear resonances

    CERN Document Server

    Rajasekar, Shanmuganathan

    2016-01-01

    This introductory text presents the basic aspects and most important features of various types of resonances and anti-resonances in dynamical systems. In particular, for each resonance, it covers the theoretical concepts, illustrates them with case studies, and reviews the available information on mechanisms, characterization, numerical simulations, experimental realizations, possible quantum analogues, applications and significant advances made over the years. Resonances are one of the most fundamental phenomena exhibited by nonlinear systems and refer to specific realizations of maximum response of a system due to the ability of that system to store and transfer energy received from an external forcing source. Resonances are of particular importance in physical, engineering and biological systems - they can prove to be advantageous in many applications, while leading to instability and even disasters in others. The book is self-contained, providing the details of mathematical derivations and techniques invo...

  7. Absorptive routines and international patent performance

    Directory of Open Access Journals (Sweden)

    Fernando E. García-Muiña

    2017-04-01

    We enrich the treatment of the absorptive capacity phases including the moderating effects between routines associated to the traditional potential-realized absorptive capacities. Taking into account external knowledge search strategies, the deeper external relationships, the better transference and appropriation of specific external knowledge. Nevertheless, when the moderating role of assimilation is included, cooperation agreements appear as the most efficient source of external knowledge. Finally, we show that technological tools let firms store and structure the information making easier its use for international patenting. This positive effect is reinforced in the presence of exploitation routines, since technological knowledge will better fit to the industry's key factors of success.

  8. Absorption heat pump system

    Science.gov (United States)

    Grossman, G.

    1982-06-16

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  9. Zeeman atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Hadeishi, T.; McLaughlin, R.

    1978-08-01

    The design and development of a Zeeman atomic absorption spectrometer for trace element analysis are described. An instruction manual is included which details the operation, adjustment, and maintenance. Specifications and circuit diagrams are given

  10. Multilevel parametrization of fissile nuclei resonance cross sections

    International Nuclear Information System (INIS)

    Lukyanov, A.A.; Kolesov, V.V.; Janeva, N.

    1987-01-01

    Because the resonance interference has an important influence on the resonance structure of neutron cross sections energy dependence at lowest energies, multilevel scheme of the cross section parametrization which take into account the resonance interference is used for the description with the same provisions in the regions of the interferential maximum and minimum of the resonance cross sections of the fissile nuclei

  11. Absorption Spectra of Gold Nanoparticle Suspensions

    Science.gov (United States)

    Anan'eva, M. V.; Nurmukhametov, D. R.; Zverev, A. S.; Nelyubina, N. V.; Zvekov, A. A.; Russakov, D. M.; Kalenskii, A. V.; Eremenko, A. N.

    2018-02-01

    Three gold nanoparticle suspensions are obtained, and mean radii in distributions - (6.1 ± 0.2), (11.9 ± 0.3), and (17.3 ± 0.7) nm - are determined by the transmission electron microscopy method. The optical absorption spectra of suspensions are obtained and studied. Calculation of spectral dependences of the absorption index of suspensions at values of the gold complex refractive index taken from the literature showed a significant deviation of experimental and calculated data in the region of 450-800 nm. Spectral dependences of the absorption of suspensions are simulated within the framework of the Mie-Drude theory taking into account the interband absorption in the form of an additional term in the imaginary part of the dielectric permittivity of the Gaussian type. It is shown that to quantify the spectral dependences in the region of the plasmon absorption band of nanoparticles, correction of the parameters of the interband absorption is necessary in addition to the increase of the relaxation parameter of the Drude theory. Spectral dependences of the dielectric permittivity of gold in nanodimensional state are refined from the solution of the inverse problem. The results of the present work are important for predicting the special features of operation of photonic devices and optical detonators based on gold nanoparticles.

  12. Microring resonator based modulator made by direct photodefinition of an electro-optic polymer

    NARCIS (Netherlands)

    Lam, Nghi Q.; Balakrishnan, M.; Faccini, M.; Diemeer, Mart; Klein, E.J.; Sengo, G.; Sengo, G.; Driessen, A.; Verboom, Willem; Reinhoudt, David

    2008-01-01

    A laterally coupled microring resonator was fabricated by direct photodefinition of negative photoresist SU8, containing tricyanovinylidenediphenylaminobenzene chromophore, by exploiting the low ultraviolet absorption window of this chromophore. The ring resonator was first photodefined by slight

  13. Revisiting Absorptive Capacity

    DEFF Research Database (Denmark)

    de Araújo, Ana Luiza Lara; Ulhøi, John Parm; Lettl, Christopher

    Absorptive capacity has mostly been perceived as a 'passive' outcome of R&D investments. Recently, however, a growing interest into its 'proactive' potentials has emerged. This paper taps into this development and proposes a dynamic model for conceptualizing the determinants of the complementary...... learning processes of absorptive capacity, which comprise combinative and adaptive capabilities. Drawing on survey data (n=169), the study concludes that combinative capabilities primarily enhance transformative and exploratory learning processes, while adaptive capabilities strengthen all three learning...

  14. Optical absorption measurement system

    International Nuclear Information System (INIS)

    Draggoo, V.G.; Morton, R.G.; Sawicki, R.H.; Bissinger, H.D.

    1989-01-01

    This patent describes a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature

  15. Rapid inventory taking system

    International Nuclear Information System (INIS)

    Marsden, P.S.S.F.

    1980-01-01

    A data processing system designed to facilitate inventory taking is described. The process depends upon the earliest possible application of computer techniques and the elimination of manual operations. Data is recorded in optical character recognition (OCR) 'A' form and read by a hand held wand reader. Limited validation checks are applied before recording on mini-tape cassettes. 5 refs

  16. Simulating Price-Taking

    Science.gov (United States)

    Engelhardt, Lucas M.

    2015-01-01

    In this article, the author presents a price-takers' market simulation geared toward principles-level students. This simulation demonstrates that price-taking behavior is a natural result of the conditions that create perfect competition. In trials, there is a significant degree of price convergence in just three or four rounds. Students find this…

  17. Take Three: Seasonal Flu

    Centers for Disease Control (CDC) Podcasts

    2010-09-29

    In this podcast, Dr. Joe Bresee describes how to keep from getting seasonal flu and spreading it to others by taking these three steps.  Created: 9/29/2010 by National Center for Immunization and Respiratory Diseases (NCIRD).   Date Released: 9/29/2010.

  18. Taking minutes of meetings

    CERN Document Server

    Gutmann, Joanna

    2016-01-01

    aking Minutes of Meetings guides you through the entire process behind minute taking: arranging the meeting; writing the agenda; creating the optimum environment; structuring the meeting and writing notes up accurately. The minute-taker is one of the most important and powerful people in a meeting and you can use this opportunity to develop your knowledge, broaden your horizons and build credibility within the organization. Taking Minutes of Meetings is an easy to read 'dip-in, dip-out' guide which shows you how to confidently arrange meetings and produce minutes. It provides hands-on advice about the sections of a meeting as well as tips on how to create an agenda, personal preparation, best practice advice on taking notes and how to improve your accuracy. Brand new chapters of this 4th edition include guidance on using technology to maximize effectiveness and practical help with taking minutes for a variety of different types of meetings. The creating success series of books... With over one million copi...

  19. Take action: influence diversity.

    Science.gov (United States)

    Gomez, Norma J

    2013-01-01

    Increased diversity brings strength to nursing and ANNA. Being a more diverse association will require all of us working together. There is an old proverb that says: "one hand cannot cover the sky; it takes many hands." ANNA needs every one of its members to be a part of the diversity initiative.

  20. Dual band metamaterial perfect absorber based on Mie resonances

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoming; Lan, Chuwen; Li, Bo; Zhou, Ji, E-mail: zhouji@tsinghua.edu.cn [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Bi, Ke [School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Zhao, Qian [State Key Lab of Tribology, Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084 (China)

    2016-08-08

    We numerically and experimentally demonstrated a polarization insensitive dual-band metamaterial perfect absorber working in wide incident angles based on the two magnetic Mie resonances of a single dielectric “atom” with simple structure. Two absorption bands with simulated absorptivity of 99% and 96%, experimental absorptivity of 97% and 94% at 8.45 and 11.97 GHz were achieved due to the simultaneous magnetic and electric resonances in dielectric “atom” and copper plate. Mie resonances of dielectric “atom” provide a simple way to design metamaterial perfect absorbers with high symmetry.

  1. Nonlinear phenomena at cyclotron resonance

    International Nuclear Information System (INIS)

    Subbarao, D.; Uma, R.

    1986-01-01

    Finite amplitude electromagnetic waves in a magnetoplasma which typically occur in situations as in present day wave heating, current drives and other schemes in magnetically confined fusion systems, can show qualitatively different absorption and emission characteristics around resonant frequencies of the plasma because of anharmonicity. Linear wave plasma coupling as well as weak nonlinear effects such as parametric instabilities generally overlook this important effect even though the thresholds for the two phenomena as shown here are comparable. Though the effects described here are relevant to a host of nonlinear resonance effects in fusion plasmas, the authors mainly limit themselves to ECRH

  2. Statistical reexamination of analytical method on the observed electron spin (or nuclear) resonance curves

    International Nuclear Information System (INIS)

    Kim, J.W.

    1980-01-01

    Observed magnetic resonance curves are statistically reexamined. Typical models of resonance lines are Lorentzian and Gaussian distribution functions. In the case of metallic, alloy or intermetallic compound samples, observed resonance lines are supperposed with the absorption line and the dispersion line. The analyzing methods of supperposed resonance lines are demonstrated. (author)

  3. Exciton molecule in semiconductors by two-photon absorption

    International Nuclear Information System (INIS)

    Arya, K.; Hassan, A.R.

    1976-07-01

    Direct creation of bi-exciton states by two-photon absorption in direct gap semiconductors is investigated theoretically. A numerical application to the case of CuCl shows that the two-photon absorption coefficient for bi-excitonic transitions is larger than that for two-photon interband transitions by three orders of magnitude. It becomes comparable to that for one-photon excitonic transitions for available laser intensities. The main contribution to this enhancement of the absorption coefficient for the transitions to the bi-exciton states is found to be from the resonance effect

  4. Photon absorption of calcium phosphate-based dental biomaterials

    International Nuclear Information System (INIS)

    Singh, V. P.; Badiger, N. M.; Tekin, H. O.; Kara, U.; Vega C, H. R.; Fernandes Z, M. A.

    2017-10-01

    Effective atomic number and mass energy absorption buildup factors for four calcium phosphate-based biomaterials used in dental treatments were calculated for 0.015 to 15 MeV photons. The mass energy absorption coefficients were calculated for 0.5 to 40 mean free paths of photons. In the energy region important for dental radiology the Zeff for all studied biomaterials are larger in comparison to larger energies. In x-rays for dental radiology and the energy absorption buildup factors are low, however CbMDI bio material shows a resonance at 80 keV. (Author)

  5. Wavelength mismatch effect in electromagnetically induced absorption

    Energy Technology Data Exchange (ETDEWEB)

    Bharti, Vineet [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Wasan, Ajay [Department of Physics, Indian Institute of Technology, Roorkee 247667 (India); Natarajan, Vasant [Department of Physics, Indian Institute of Science, Bangalore 560012 (India)

    2016-07-15

    We present a theoretical investigation of the phenomenon of electromagnetically induced absorption (EIA) in a 4-level system consisting of vee and ladder subsystems. The four levels are coupled using one weak probe field, and two strong control fields. We consider an experimental realization using energy levels of Rb. This necessitates dealing with different conditions of wavelength mismatch—near-perfect match where all three wavelengths are approximately equal; partial mismatch where the wavelength of one control field is less than the other fields; and complete mismatch where all three wavelengths are unequal. We present probe absorption profiles with Doppler averaging at room temperature to account for experiments in a room temperature Rb vapor cell. Our analysis shows that EIA resonances can be studied using Rydberg states excited with diode lasers. - Highlights: • Wavelength mismatch effect is investigated in electromagnetically induced absorption (EIA). • An experimental realization of 4-level vee + ladder system using energy levels of rubidium atom is presented. • EIA resonances are studied under different conditions of wavelength mismatch. • Possibility of observation of EIA using Rydberg states excited with diode lasers.

  6. Wavelength mismatch effect in electromagnetically induced absorption

    International Nuclear Information System (INIS)

    Bharti, Vineet; Wasan, Ajay; Natarajan, Vasant

    2016-01-01

    We present a theoretical investigation of the phenomenon of electromagnetically induced absorption (EIA) in a 4-level system consisting of vee and ladder subsystems. The four levels are coupled using one weak probe field, and two strong control fields. We consider an experimental realization using energy levels of Rb. This necessitates dealing with different conditions of wavelength mismatch—near-perfect match where all three wavelengths are approximately equal; partial mismatch where the wavelength of one control field is less than the other fields; and complete mismatch where all three wavelengths are unequal. We present probe absorption profiles with Doppler averaging at room temperature to account for experiments in a room temperature Rb vapor cell. Our analysis shows that EIA resonances can be studied using Rydberg states excited with diode lasers. - Highlights: • Wavelength mismatch effect is investigated in electromagnetically induced absorption (EIA). • An experimental realization of 4-level vee + ladder system using energy levels of rubidium atom is presented. • EIA resonances are studied under different conditions of wavelength mismatch. • Possibility of observation of EIA using Rydberg states excited with diode lasers.

  7. Taking of history

    DEFF Research Database (Denmark)

    Langebæk, Rikke

    2007-01-01

    the smartest student. So the more familiar a student can become with these situations the better. Since september 2006, veterinary students at Faculty of Life Sciences, University of Copenhagen, have received training in the discipline of history taking, using innovative educational methods: Online......, the students won’t be intimidated by the situation, as they are already familiar with the ‘client’. The ‘client’/teacher must be able to perform as different types of clients to make the sessions more interesting, colourful and fun. During these Live Role sessions, the students will get help and good advice......Learning how to take a history is an extremely important discipline in the education of veterinary students. In our opinion the fact that this discipline is often neglected in traditional teaching is a big mistake. The mere thought of facing a real client can be almost paralysing to even...

  8. Take the "C" Train

    Science.gov (United States)

    Lawton, Rebecca

    2008-01-01

    In this essay, the author recalls several of her experiences in which she successfully pulled her boats out of river holes by throwing herself to the water as a sea-anchor. She learned this trick from her senior guides at a spring training. Her guides told her, "When you're stuck in a hole, take the "C" train."" "Meaning?" The author asked her…

  9. Social Perspective Taking

    Science.gov (United States)

    2009-09-01

    groups” and engage in less stereotype-driven fear and hostility resulting in reduced impulsive and aggressive behavior (Richardson, Green , & Lago...and the physical world. London: Routledge & Kegan Paul. Batson, C. D. (1991). The altruism question: Towards a social-psychological answer...others. New York: The Guilford Press. Richardson, D. R., Green , L. R., & Lago, T. (1998). The relationship between perspective- taking and

  10. Perspective Taking in Workplaces

    Directory of Open Access Journals (Sweden)

    Zappalà Salvatore

    2014-07-01

    Full Text Available Workplaces are often described as places in which individuals are motivated by their self-interests and in which negative events like time pressure, anxiety, conflict with co-workers, miscomprehensions, difficulties in solving problems, not-transmitted or not-exchanged information that lead to mistakes, and in some cases to injuries, stress or control, are part of everyday life (Dormann & Zapf, 2002; Schabracq, Winnubst and Cooper, 2003. Such situations are often the result of the limited comprehension of needs, skills, or information available to colleagues, supervisors, subordinates, clients or providers. However, workplaces are also places in which employees take care of clients, support colleagues and subordinates (Rhoades & Eisenberger, 2002, are enthusiastic about their job (Bakker et al., 2008, are motivated by leaders that encourage employees to transcend their own self-interests for the good of the group or the organization and provide them with the confidence to perform beyond expectations (Bass, 1997. Thus positive relationships at work are becoming a new interdisciplinary domain of inquiry (Dutton & Ragins, 2006. Within this positive relationships framework, in this paper we focus on a positive component of workplaces, and particularly on an individual cognitive and emotional process that has an important role in the workplace because it facilitates interpersonal relations and communications: it is the perspective taking process. In order to describe perspective taking, we will refer to some empirical studies and particularly to the review published by Parker, Atkins and Axtell in 2008 on the International Review of Industrial and Organizational Psychology.

  11. Synthesis and purification of some alkyl phenanthrenes and presentation of their infrared, ultraviolet, nuclear magnetic resonance and mass spectra; Synthese et purification de quelques alcoylphenanthrenes et presentation ds leurs spectres d'absorption infrarouge, ultraviolette, de resonance magnetique nucleaire et de masse

    Energy Technology Data Exchange (ETDEWEB)

    Persaud, K. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1965-01-01

    We have carried out the synthesis of: - phenanthrene - its five monomethyl derivatives - three dimethyl derivatives - two trimethyl derivatives. We have then purified these products as well as a certain number of others obtained from various sources. We have been able to obtain in the majority of cases, a purity of 99.5 per cent or over, these figures being obtained by low voltage mass spectrometry. Finally we have recorded the infrared, ultraviolet, nuclear magnetic resonance and mass spectra of these products for which an atlas has been drawn up. (author) [French] Nous avons realise la synthese: - du phenanthrene - de ses cinq derives monomethyles - de trois de ses derives dimethyles - de deux de ses derives trimethyles. Nous avons ensuite purifie ces produits ainsi qu'un certain nombre d'autres que nous avons obtenus de sources differentes. Nous avons pu atteindre, dans la plupart des cas, une purete egale ou superieure a 99,5 pour cent, chiffres determines par la spectrometrie de masse a basse tension. Enfin, nous avons enregistre les spectres infrarouges, ultraviolets, de resonance magnetique nucleaire et de masse de ces produits dont nous avons fait un atlas. (auteur)

  12. Vitamin A absorption

    International Nuclear Information System (INIS)

    Baker, S.J.

    1976-01-01

    Investigation of the absorption of vitamin A and related substances is complicated by the multiplicity of forms in which they occur in the diet and by the possibility that they may be subject to different mechanisms of absorption. Present knowledge of these mechanisms is inadequate, especially in the case of carotenoids. Numerous tests of absorption have been developed. The most common has been the biochemical measurement of the rise in plasma vitamin A after an oral dose of retinol or retinyl ester, but standardization is inadequate. Radioisotope tests based upon assay of serum or faecal activity following oral administration of tritiated vitamin A derivaties hold considerable promise, but again standardization is inadequate. From investigations hitherto performed it is known that absorption of vitamin A is influenced by several diseases, although as yet the consistency of results and the correlation with other tests of intestinal function have often been poor. However, the test of vitamin A absorption is nevertheless of clinical importance as a specialized measure of intestinal function. (author)

  13. Nucleon structure functions, resonance form factors, and duality

    International Nuclear Information System (INIS)

    Davidovsky, V.V.; Struminsky, B.V.

    2003-01-01

    The behavior of nucleon structure functions in the resonance region is explored. For form factors that describe resonance production, expressions are obtained that are dependent on the photon virtuality Q 2 , which have a correct threshold behavior, and which take into account available experimental data on resonance decay. Resonance contributions to nucleon structure functions are calculated. The resulting expressions are used to investigate quark-hadron duality in electron-nucleon scattering by taking the example of the structure function F 2

  14. Interferometric measurement of lines shift in flames in connection with interpretation of lined absorption method in atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    L'vov, B.V.; Polzik, L.K.; Katskov, D.A.; Kruglikova, L.P.

    1975-01-01

    This paper is concerned with interferometric measuring of the line shift in flames in the view of interpretation of absorption lines in the atomic absorption spectroscopy. The newly measured line shifts were compared to the known data on Lorentz broadening of the same lines obtained by methods free of the systematic errors. The resonant lines of the alkaline earth elements (Sr, Ca, Ba) were investigated. To reduce self-absorption in the flame the solutions with minimum concentrations of the elements were used. The computation scheme includes the spectrometer apparatus width and line broadening due to the self-absorption. Formulae are given for computing the values studied. Good agreement was observed between the computed and experimental results. Error analysis was performed. It was concluded that any line shifts in the hydrocarbons were correctly taken into an account in the absolute computations of absorption

  15. In Vitro Studies on the Absorption and Interactions of Zinc, Copper ...

    African Journals Online (AJOL)

    Background: The exact details of the processes of trace metals absorption and interactions in the gastro intestinal tract remain uncertain. Absorption for the most part, takes places in the small intestine. The exact site of maximum absorption, as defined either by kinetic rate or quantity has not been clearly defined. Similarly ...

  16. One, two or three-nucleon photo- absorption in 3He

    International Nuclear Information System (INIS)

    Tamas, G.

    1986-08-01

    Pion production and photodisintegration of 3 He are studied in the δ resonance region to try to separate the various photon absorption mechanism by one, two or three nucleons. The results are compared to the existing models

  17. On the synthesis of resonance lines in dynamical models of structured hot-star winds

    Science.gov (United States)

    Puls, J.; Owocki, S. P.; Fullerton, A. W.

    1993-01-01

    We examine basic issues involved in synthesizing resonance-line profiles from 1-D, dynamical models of highly structured hot-star winds. Although these models exhibit extensive variations in density as well as velocity, the density scale length is still typically much greater than the Sobolev length. The line transfer is thus treated using a Sobolev approach, as generalized by Rybicki & Hummer (1978) to take proper account of the multiple Sobolev resonances arising from the nonmonotonic velocity field. The resulting reduced-lambda-matrix equation describing nonlocal coupling of the source function is solved by iteration, and line profiles are then derived from formal solution integration using this source function. Two more approximate methods that instead use either a stationary or a structured, local source function yield qualitatively similar line-profiles, but are found to violate photon conservation by 10% or more. The full results suggest that such models may indeed be able to reproduce naturally some of the qualitative properties long noted in observed UV line profiles, such as discrete absorption components in unsaturated lines, or the blue-edge variability in saturated lines. However, these particular models do not yet produce the black absorption troughs commonly observed in saturated lines, and it seems that this and other important discrepancies (e.g., in acceleration time scale of absorption components) may require development of more complete models that include rotation and other 2-D and/or 3-D effects.

  18. Take nothing for granted

    International Nuclear Information System (INIS)

    Turner, R.

    1998-01-01

    An overview of Western Canada Sedimentary Basin (WCSB) natural gas supply, past, present and future, was presented. Reserves are considered as being more than adequate to meet supply requirements. In the long term, it is expected that there will be sufficient gas to fill all existing and currently planned pipelines serving the WCSB. Nevertheless, it does not pay to take anything for granted. One of the challenges facing the natural gas industry in an integrated North American market is to maintain a balance between deliverability and take-away capacity. Competition between fuels is also a factor that complicates matters. Measures taken by TransCanada Pipelines to prepare for the expected heightened competition were reviewed. Chief among them is the recent TransCanada/Nova merger which is expected to increase efficiency, decrease costs, provide a solid platform for continued growth, create customer-driven energy solutions and enable the new entity to successfully compete in an integrated North American market. The accord reached between CAPP, NOVA, SEPAC and TransCanada Pipelines and the status of the new Alberta tolls are further examples of measures taken by TransCanada Pipelines to prepare for all contingencies by leaving nothing to chance

  19. Far-Infrared Absorption of PbSe Nanorods

    KAUST Repository

    Hyun, Byung-Ryool; Bartnik, A. C.; Koh, Weon-kyu; Agladze, N. I.; Wrubel, J. P.; Sievers, A. J.; Murray, Christopher B.; Wise, Frank W.

    2011-01-01

    Measurements of the far-infrared absorption spectra of PbSe nanocrystals and nanorods are presented. As the aspect ratio of the nanorods increases, the Fröhlich sphere resonance splits into two peaks. We analyze this splitting with a classical

  20. On the absorption of a sound in helium 2

    International Nuclear Information System (INIS)

    Matveev, Yu.A.

    1977-01-01

    A theory is developed which describes the propagation of high frequency sound in helium 2 at low temperatures (T 15 atm.) pressures when the phonon energy spectrum becomes stable. The absorption and sound dispersion coefficients under these conditions are calculated. The dependence of the velocity of second sound on frequency is determined. The resonance properties of the solution obtained are discussed

  1. Cyclotron resonant gas breakdown with a 1.22-nm 13CH3F laser

    International Nuclear Information System (INIS)

    Hacker, M.P.; Lax, B.; Metz, R.N.; Temkin, R.J.

    1979-01-01

    Cyclotron-resonant laser-induced gas breakdown has been studied for the first time in the transverse geometry, using 1.222-nm 13 CH 3 F laser radiation propagating perpendicular to the magnetic field axis. The line shape of absorbed laser radiation versus magnetic field near electron cyclotron resonance (87.75 kG) indicates a strong dependence of the line shape on the focused laser intensity. This dependence is not predicted by the standard equilibrium theory of high-frequency gas breakdown in a magnetic field. We have developed an analytic theory to explain the observed line shapes. The theory takes into account the laser propagation characteristics, in particular that there is nonuniform ionization due to strong resonant absorption of the laser radiation in a length comparable to or shorter than that of the laser focal volume. The transverse geometry simplifies the theoretical analysis because the observed line shapes are not significantly affected by Doppler broadening. Extensive data have been obtained on the fraction of laser pulse energy absorbed in the gas breakdown volume as a function of magnetic field, helium gas pressure, and incident laser pulse energy. Good quantitative agreement is obtained between the observed laser pulse absorption line shapes and the nonuniform ionization theory

  2. Taking Care of Your Hair

    Science.gov (United States)

    ... Educators Search English Español Taking Care of Your Hair KidsHealth / For Teens / Taking Care of Your Hair ... role in how healthy it looks. Caring for Hair How you take care of your hair depends ...

  3. Molecular geometry in the ultraviolet absorption spectra

    International Nuclear Information System (INIS)

    Albuquerque, S.F. de; Monteiro, L.S.; Adamis, L.M.B.; Baltar, M.C.P.; Silva, R.M. da

    1977-01-01

    The ultraviolet absorption spectra may be sensibly affected by steric effects. These effects can cause a lot of difficulties and unexpected changes in spectrum. The most general source of such difficulties is steric inhibition of resonance. In addition to this, ultraviolet epectra may be markedly changed by steric factors which change the positions of dipoles in the molecule with respect to each other and by the interaction of nonconjugated chromophores suitably located in space. We have studied in detail each of these effects presenting a lot of usual and importants examples in Organic Chemistry. Others relevants subjects were not considerated in this present work [pt

  4. Noble gas absorption process

    International Nuclear Information System (INIS)

    Thomas, J.W.

    1975-01-01

    A method of removing a noble gas from air comprising the use of activated carbon filters in stages in which absorption and desorption steps in succession are conducted in order to increase the capacity of the filters is described. (U.S.)

  5. Chemical Absorption Materials

    DEFF Research Database (Denmark)

    Thomsen, Kaj

    2011-01-01

    Chemical absorption materials that potentially can be used for post combustion carbon dioxide capture are discussed. They fall into five groups, alkanolamines, alkali carbonates, ammonia, amino acid salts, and ionic liquids. The chemistry of the materials is discussed and advantages and drawbacks...

  6. Giant 4p-quadrupole resonances in the Rare Earths

    International Nuclear Information System (INIS)

    Matthew, J.A.D.; Netzer, F.P.; Clark, C.W.; Morar, J.F.

    1987-01-01

    X-ray absorption of Ce obtained by partial secondary yield, is compared with previously obtained electron-energy loss measurements in reflection mode. The absence of a strong feature below 4p 3/2 threshold in photon absorption provides confirmation that the peak in EELS is nondipole in character. Theoretical analysis supports interpretation in terms of a p-f giant quadrupole resonance, a result which broadens the analogy between giant resonances in atomic and nuclear physics

  7. Taking action against violence.

    Science.gov (United States)

    Kunz, K

    1996-05-01

    Significant increase in violent crimes in recent years forced Icelandic men to take action against violence. Television was seen as a major contributory factor in increasing violence. Surveys indicate that 10-15 years after television broadcasting commences in a particular society, the incidence of crime can be expected to double. While the majority of the individuals arrested for violent crimes are men, being male does not necessarily mean being violent. The Men's Committee of the Icelandic Equal Rights Council initiated a week-long information and education campaign under the theme "Men Against Violence". This campaign involved several events including an art exhibit, speeches on violence in families, treatment sought by those who are likely to resort to violence, booklet distribution among students in secondary schools, and a mass media campaign to raise public awareness on this pressing problem.

  8. Taking Design Games Seriously

    DEFF Research Database (Denmark)

    Eriksen, Mette Agger; Brandt, Eva; Mattelmäki, Tuuli

    2014-01-01

    Using design games at Participatory Design (PD) events is well acknowledged as a fruitful way of staging participation. As PD researchers, we have many such experiences, and we have argued that design games connect participants and promote equalizing power relations. However, in this paper, we...... will (self) critically re-connect and reflect on how people (humans) and materials (non-humans) continually participate and intertwine in various power relations in design game situations. The analysis is of detailed situated actions with one of our recent games, UrbanTransition. Core concepts mainly from...... Bruno Latour’s work on Actor-Network-Theory are applied. The aim is to take design games seriously by e.g. exploring how assemblages of humans and non-humans are intertwined in tacitly-but-tactically staging participation, and opening up for or hindering negotiations and decision-making, thus starting...

  9. Multiquark Resonances

    CERN Document Server

    Esposito, A.; Polosa, A.D.

    2016-01-01

    Multiquark resonances are undoubtedly experimentally observed. The number of states and the amount of details on their properties has been growing over the years. It is very recent the discovery of two pentaquarks and the confirmation of four tetraquarks, two of which had not been observed before. We mainly review the theoretical understanding of this sector of particle physics phenomenology and present some considerations attempting a coherent description of the so called X and Z resonances. The prominent problems plaguing theoretical models, like the absence of selection rules limiting the number of states predicted, motivate new directions in model building. Data are reviewed going through all of the observed resonances with particular attention to their common features and the purpose of providing a starting point to further research.

  10. Neuroaesthetic Resonance

    DEFF Research Database (Denmark)

    Brooks, Anthony Lewis

    2013-01-01

    Neuroaesthetic Resonance emerged from a mature body of patient- centered gesture-control research investigating non-formal rehabilitation via ICT-enhanced-Art to question ‘Aesthetic Resonance’. Motivating participation, ludic engagement, and augmenting physical motion in non-formal (fun) treatment...... sessions are achieved via adaptive action-analyzed activities. These interactive virtual environments are designed to empower patients’ creative and/or playful expressions via digital feedback stimuli. Unconscious self- pushing of limits result from innate distractive mechanisms offered by the alternative...... the unencumbered motion-to-computer-generated activities - ‘Music Making’, ‘Painting’, ‘Robotic’ and ‘Video Game’ control. A focus of this position paper is to highlight how Aesthetic Resonance, in this context, relates to the growing body of research on Neuroaesthetics to evolve Neuroaesthetic Resonance....

  11. Baryon Resonances

    International Nuclear Information System (INIS)

    Oset, E.; Sarkar, S.; Sun Baoxi; Vicente Vacas, M.J.; Ramos, A.; Gonzalez, P.; Vijande, J.; Martinez Torres, A.; Khemchandani, K.

    2010-01-01

    In this talk I show recent results on how many excited baryon resonances appear as systems of one meson and one baryon, or two mesons and one baryon, with the mesons being either pseudoscalar or vectors. Connection with experiment is made including a discussion on old predictions and recent results for the photoproduction of the Λ(1405) resonance, as well as the prediction of one 1/2 + baryon state around 1920 MeV which might have been seen in the γp→K + Λ reaction.

  12. Energy absorption in cold inhomogeneous plasmas - The Herlofson paradox.

    Science.gov (United States)

    Crawford, F. W.; Harker, K. J.

    1972-01-01

    Confirmation of Barston's (1964) conclusions regarding the underlying mechanism of the Herlofson paradox by examining in detail several analytically tractable cases of delta-function and sinusoidal excitation. The effects of collisions and nonzero electron temperature in determining the steady state fields and dissipation are considered. Energy absorption without dissipation in plasmas is shown to be analogous to that occurring after application of a signal to a network of lossless resonant circuits. This analogy is pursued and is extended to cover Landau damping in a warm homogeneous plasma in which the resonating elements are the electron streams making up the velocity distribution. Some of the practical consequences of resonant absorption are discussed, together with a number of paradoxical plasma phenomena which can also be elucidated by considering a superposition of normal modes rather than a single Fourier component.

  13. Atomic resonances in nuclear fusion plasmas

    International Nuclear Information System (INIS)

    Clauser, C. F.; Barrachina, R. O.

    2013-01-01

    We present a study of zero energy resonances of photoionization and radiative recombination cross section for the different species in a fusion reactor. In this context, the interaction potential is screened and its typical length depends on the plasma density and temperature. Due to the nature of these resonances, we propose other atomic processes in which they can take place. Finally, we show the density and temperature conditions where these resonances occur and their probable consequence on the reactor performance. (author)

  14. Enhanced index and negative dispersion without absorption in driven cascade media

    International Nuclear Information System (INIS)

    Hu Xiangming; Xu Jun

    2004-01-01

    In this paper we investigate the dispersive and absorptive properties of a system of three-level cascade atoms driven by a strong coherent field. Three characteristic features are found. First, for the same set of atom-light interaction parameters, the indices of refraction are large at three different frequencies where the absorption vanishes. These three frequencies are determined by the resonance transition frequencies between dressed states produced by the strong driving field. Second, negative dispersion without absorption, which leads to superluminal light propagation, is achievable in the central resonance structure of the dispersion spectrum. Third, the whole absorption spectrum displays, in general, three pairs of absorption peaks and three pairs of gain (negative absorption) peaks. The minimal spacing between dressed states determines whether the outer adjacent gain peaks are separated from each other

  15. Electron Dynamics in the Core-Excited CS 2 Molecule Revealed through Resonant Inelastic X-Ray Scattering Spectroscopy

    OpenAIRE

    Marchenko , T; Carniato , S; Journel , L; Guillemin , R; Kawerk , E; Žitnik , M; Kavčič , M; Bučar , K; Bohinc , R; Petric , M; Vaz Da Cruz , V; Gel 'mukhanov , F; Simon , Marielle

    2015-01-01

    International audience; We present an experimental and theoretical study of resonant inelastic x-ray scattering (RIXS) in the carbon disulphide CS 2 molecule near the sulfur K-absorption edge. We observe a strong evolution of the RIXS spectral profile with the excitation energy tuned below the lowest unoccupied molecular orbital (LUMO) absorption resonance. The reason for this is twofold. Reducing the photon energy in the vicinity of the LUMO absorption resonance leads to a relative suppressi...

  16. Acoustic absorption behaviour of an open-celled aluminium foam

    International Nuclear Information System (INIS)

    Han Fusheng; Seiffert, Gary; Zhao Yuyuan; Gibbs, Barry

    2003-01-01

    Metal foams, especially close-celled foams, are generally regarded as poor sound absorbers. This paper studies the sound absorption behaviour of the open-celled Al foams manufactured by the infiltration process, and the mechanisms involved. The foams show a significant improvement in sound absorption compared with close-celled Al foams, because of their high flow resistance. The absorption performance can be further enhanced, especially at low frequencies, if the foam panel is backed by an appropriate air gap. Increasing the air-gap depth usually increases both the height and the width of the absorption peak and shifts the peak towards lower frequencies. The foam samples with the smallest pore size exhibit the best absorption capacities when there is no air gap, whereas those with medium pore sizes have the best overall performance when there is an air gap. The typical maximum absorption coefficient, noise reduction coefficient and half-width of the absorption peak are 0.96-0.99, 0.44-0.62 and 1500-3500 Hz, respectively. The sound dissipation mechanisms in the open-celled foams are principally viscous and thermal losses when there is no air-gap backing and predominantly Helmholtz resonant absorption when there is an air-gap backing

  17. Enhancement of resonant absorption through excitation of SPR

    Czech Academy of Sciences Publication Activity Database

    Giulietti, D.; Calcagno, L.; Curcio, A.; Cutroneo, Mariapompea; Galletti, M.; Skála, Jiří; Torrisi, L.; Zimbone, M.

    Roč. 829, SEP (2016), s. 117-120 ISSN 0168-9002. [2nd Workshop on European Advanced Accelerator Concepts (EAAC). Isolda d'Elba, 13.09.2015-19.05.2015] Institutional support: RVO:68378271 ; RVO:61389005 Keywords : laser-solid target interaction * nanoparticle implantation * surface plasmons * electronic plasma waves Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders; BL - Plasma and Gas Discharge Physics (FZU-D) Impact factor: 1.362, year: 2016

  18. Looking inside giant resonance fine structure

    International Nuclear Information System (INIS)

    Ponomarev, V.Yu.; Voronov, V.V.

    1993-01-01

    Microscopic calculations of the fine structure of giant resonances for spherical nuclei are presented. Excited states are treated by wave function which takes into account coupling of simple one-phonon configurations with more complex ones. Nuclear structure calculations are applied to the description of the γ-decay of resonances into the ground and low-lying excited states. 16 refs.; 4 figs

  19. Structural characterization of CO-inhibited Mo-nitrogenase by combined application of nuclear resonance vibrational spectroscopy, extended X-ray absorption fine structure, and density functional theory: new insights into the effects of CO binding and the role of the interstitial atom.

    Science.gov (United States)

    Scott, Aubrey D; Pelmenschikov, Vladimir; Guo, Yisong; Yan, Lifen; Wang, Hongxin; George, Simon J; Dapper, Christie H; Newton, William E; Yoda, Yoshitaka; Tanaka, Yoshihito; Cramer, Stephen P

    2014-11-12

    The properties of CO-inhibited Azotobacter vinelandii (Av) Mo-nitrogenase (N2ase) have been examined by the combined application of nuclear resonance vibrational spectroscopy (NRVS), extended X-ray absorption fine structure (EXAFS), and density functional theory (DFT). Dramatic changes in the NRVS are seen under high-CO conditions, especially in a 188 cm(-1) mode associated with symmetric breathing of the central cage of the FeMo-cofactor. Similar changes are reproduced with the α-H195Q N2ase variant. In the frequency region above 450 cm(-1), additional features are seen that are assigned to Fe-CO bending and stretching modes (confirmed by (13)CO isotope shifts). The EXAFS for wild-type N2ase shows evidence for a significant cluster distortion under high-CO conditions, most dramatically in the splitting of the interaction between Mo and the shell of Fe atoms originally at 5.08 Å in the resting enzyme. A DFT model with both a terminal -CO and a partially reduced -CHO ligand bound to adjacent Fe sites is consistent with both earlier FT-IR experiments, and the present EXAFS and NRVS observations for the wild-type enzyme. Another DFT model with two terminal CO ligands on the adjacent Fe atoms yields Fe-CO bands consistent with the α-H195Q variant NRVS. The calculations also shed light on the vibrational "shake" modes of the interstitial atom inside the central cage, and their interaction with the Fe-CO modes. Implications for the CO and N2 reactivity of N2ase are discussed.

  20. Seventh annual symposium on the anomalous absorption of intense high-frequency waves

    International Nuclear Information System (INIS)

    1977-01-01

    Abstracts are given for fifty-five papers presented at the conference. The papers covered the following topics: profile modification and related phenomena, nonlinear wave-plasma interactions, profile modification and resonance absorption, fast particles and related phenomena, anomalous transport, magnetic field effects, and absorption and other experiments

  1. Pondermotive absorption of a short intense laser pulse in a non-uniform plasma

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, A A; Platonov, K Yu [Inst. for Laser Physics, SC ` Vavilov State Optical Inst.` 12, Birzhevaya line, St Petersburg (Russian Federation); Tanaka, K A

    1998-03-01

    An analytical description of the pondermotive absorption mechanism at a short high intense laser pulse interaction with a strong inhomogeneous plasma is presented. The optimal conditions for the maximum of resonance absorption of laser pulse interaction with non-uniform plasma at normal incidence are founded. (author)

  2. Laser light absorption and harmonic generation due to self-generated magnetic fields

    International Nuclear Information System (INIS)

    Kruer, W.L.; Estabrook, K.G.

    1977-01-01

    It is shown that self-generated magnetic fields can play a significant role in laser light absorption. Even normally incident light will then be resonantly absorbed. Computer simulations and theoretical estimates for this absorption and the concomitant harmonic generation are given for parameters characteristic of some recent experiments

  3. High-Resolution X-ray Emission and X-ray Absorption Spectroscopy

    NARCIS (Netherlands)

    Groot, F.M.F. de

    2000-01-01

    In this review, high-resolution X-ray emission and X-ray absorption spectroscopy will be discussed. The focus is on the 3d transition-metal systems. To understand high-resolution X-ray emission and reso-nant X-ray emission, it is first necessary to spend some time discussing the X-ray absorption

  4. Absorption of aluminium X-ray lines in a laser created gold plasma

    International Nuclear Information System (INIS)

    Combis, P.; Busquet, M.; Louis-Jacquet, M.

    1986-04-01

    We have studied the absorption of aluminium X-ray lines through a gold plasma by focusing a high intensity laser-beam onto a specific target. Absorption in the wavelength range of 5 to 7 A has been evidenced and measured for Aluminium resonance lines

  5. Determination of self-absorption in emission lines from some optically thick plasmas

    International Nuclear Information System (INIS)

    Pianarosa, P.; Gagne, J.M.; Larin, G.; Saint-Dizier, J.P.

    1982-01-01

    We present a relatively simple method by which the amount of self-absorption in laboratory-produced plasmas can be evaluated. As an illustration we apply it here to the evaluation of self-absorption of a U I resonance transition from a hollow-cathode-generated plasma. The method can be generalized to include more-complex situations

  6. 996 RESONANCE November 2013

    Indian Academy of Sciences (India)

    IAS Admin

    996. RESONANCE. November 2013. Page 2. 997. RESONANCE. November 2013. Page 3. 998. RESONANCE. November 2013. Page 4. 999. RESONANCE. November 2013. Page 5. 1000. RESONANCE. November 2013. Page 6. 1001. RESONANCE. November 2013. Page 7. 1002. RESONANCE. November 2013 ...

  7. 817 RESONANCE September 2013

    Indian Academy of Sciences (India)

    IAS Admin

    817. RESONANCE ⎜ September 2013. Page 2. 818. RESONANCE ⎜ September 2013. Page 3. 819. RESONANCE ⎜ September 2013. Page 4. 820. RESONANCE ⎜ September 2013. Page 5. 821. RESONANCE ⎜ September 2013. Page 6. 822. RESONANCE ⎜ September 2013. Page 7. 823. RESONANCE ⎜ September ...

  8. 369 RESONANCE April 2016

    Indian Academy of Sciences (India)

    IAS Admin

    369. RESONANCE ⎜ April 2016. Page 2. 370. RESONANCE ⎜ April 2016. Page 3. 371. RESONANCE ⎜ April 2016. Page 4. 372. RESONANCE ⎜ April 2016. Page 5. 373. RESONANCE ⎜ April 2016. Page 6. 374. RESONANCE ⎜ April 2016. Page 7. 375. RESONANCE ⎜ April 2016.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-16

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

  10. Observation of Antiferromagnetic Resonance in an Organic Superconductor

    DEFF Research Database (Denmark)

    Torrance, J. B.; Pedersen, H. J.; Bechgaard, K.

    1982-01-01

    Anomalous microwave absorption has been observed in the organic superconductor TMTSF2AsF6 (TMTSF: tetramethyltetraselenafulvalene) below its metal-nonmetal transition near 12 K. This absorption is unambiguously identified as antiferromagnetic resonance by the excellent agreement between a spin...

  11. Electro-Mechanical Resonance Curves

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    2018-01-01

    Recently I have been investigating the frequency response of galvanometers. These are direct-current devices used to measure small currents. By using a low-frequency function generator to supply the alternating-current signal and a stopwatch smartphone app to measure the period, I was able to take data to allow a resonance curve to be drawn. This…

  12. Medicaid: taking stock.

    Science.gov (United States)

    Davidson, S M

    1993-01-01

    In the last few years, Medicaid has attracted more than casual attention, one reflection of which is the fact that JHPPL has published five papers on the program in its last few issues. This paper, a sixth, takes a broader view of the program than is typically the case. After a critique of the five recent articles, I discuss several questions raised by them and reach the following conclusions: First, the states do not invest enough in producing program data suitable for policy analysis and research. One lesson: Better data and analysis can help the states to avoid expensive mistakes. Second, those policy analyses that have been offered fail to give sufficient attention to the political dimension of policy. That is one reason why policy choices produce unexpected effects. Third, since Medicaid is a relatively small player in the vast medical care market, incentives adopted by Medicaid officials throughout the country rarely have the desired effects. Finally, as long as Medicaid remains the principal mechanism to provide access to health care for the poor, it must be made as efficient and effective as possible. Yet, for both political and economic reasons, Medicaid can never be what its original planners had hoped, the vehicle for providing the poor with reliable access to mainstream medical care.

  13. Taking the plunge

    CERN Multimedia

    2008-01-01

    On 8 and 15 October, 58 people took the plunge and headed to the Varembé swimming pool in Geneva for their first taste of scuba diving at one of the CERN scuba club’s free trial dives. Club president Alberto Pace, left, taking a new recruit on his first dive. The CERN scuba club was making waves down at the Varembe swimming pool on Wednesday 15 October. Thirty-six people turned up to the club’s second free trial dive. "It was fantastic," said Jörg, one of the new recruits, after his first ever dive. "I’ve always wanted to try diving and this was a free lesson, so I thought I would come and have a go." Fourteen of the club’s fully qualified instructors were there to give one-on-one tuition. After a first dive in the normal pool the new divers moved into the deep pool. Some took to the water like fish, and at one point an impromptu game of aqua-Frisbee broke out, five metres below the surface. Richard Catherall, who organi...

  14. Sample-taking apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Tanov, Y I; Ismailov, R A; Orazov, A

    1980-10-07

    The invention refers to the equipment for testing water-bearing levels in loose rocks. Its purpose is to simultaneously remove with the rock sample a separate fluid sample from the assigned interval. The sample-taking apparatus contains a core lifter which can be submerged into the casting string with housing and front endpiece in the form of a rod with a piston which covers the cavity of the core lifter, as well as mechanism for fixing and moving the endpiece within the core lifter cavity. The device differs from the known similar devices because the upper part of the housing of the core lifter is equipped with a filter and mobile casting which covers the filter. In this case the casing is connected to the endpiece rod and the endpiece is installed with the possibility of movement which is limited with fixing in the upper position and in the extreme upper position it divides the core lifter cavity into two parts, filter settling tank and core-receiving cavity.

  15. Synchrobetatron resonances

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    At the 1975 Particle Accelerator Conference it was reported that a class of resonances were observed in SPEAR II that had not appeared before in SPEAR I. These resonances occur when the betatron oscillation wave numbers ν/sub x/ or ν/sub y/ and the synchrotron wave number ν/sub s/ satisfy the relation (ν/sub x,y/ - mν/sub s/) = 5, with m an integer denoting the m/sup th/ satellite. The main difference between SPEAR II and SPEAR I is the value of ν/sub s/, which in SPEAR II is approximately 0.04, an order of magnitude larger than in SPEAR I. An ad hoc meeting was held at the 1975 Particle Accelerator Conference, where details of the SPEAR II results were presented and various possible mechanisms for producing these resonances were discussed. Later, experiments were performed at SPEAR to identify the mechanism believed to be the most likely explanation. Some of the current experimental knowledge and theoretical views on the source of these resonances are presented

  16. Autostereogram resonators

    Science.gov (United States)

    Leavey, Sean; Rae, Katherine; Murray, Adam; Courtial, Johannes

    2012-09-01

    Autostereograms, or "Magic Eye" pictures, are repeating patterns designed to give the illusion of depth. Here we discuss optical resonators that create light patterns which, when viewed from a suitable position by a monocular observer, are autostereograms of the three-dimensional shape of one of the mirror surfaces.

  17. Decision taking as a service

    NARCIS (Netherlands)

    Bergstra, J.A.

    2012-01-01

    Decision taking can be performed as a service to other parties and it is amenable to outtasking rather than to outsourcing. Outtasking decision taking is compatible with selfsourcing of decision making activities carried out in preparation of decision taking. Decision taking as a service (DTaaS) is

  18. Particle-in-a-box model of exciton absorption and electroabsorption in conjugated polymers

    Science.gov (United States)

    Pedersen, Thomas G.

    2000-12-01

    The recently proposed particle-in-a-box model of one-dimensional excitons in conjugated polymers is applied in calculations of optical absorption and electroabsorption spectra. It is demonstrated that for polymers of long conjugation length a superposition of single exciton resonances produces a line shape characterized by a square-root singularity in agreement with experimental spectra near the absorption edge. The effects of finite conjugation length on both absorption and electroabsorption spectra are analyzed.

  19. Linear absorptive dielectrics

    Science.gov (United States)

    Tip, A.

    1998-06-01

    Starting from Maxwell's equations for a linear, nonconducting, absorptive, and dispersive medium, characterized by the constitutive equations D(x,t)=ɛ1(x)E(x,t)+∫t-∞dsχ(x,t-s)E(x,s) and H(x,t)=B(x,t), a unitary time evolution and canonical formalism is obtained. Given the complex, coordinate, and frequency-dependent, electric permeability ɛ(x,ω), no further assumptions are made. The procedure leads to a proper definition of band gaps in the periodic case and a new continuity equation for energy flow. An S-matrix formalism for scattering from lossy objects is presented in full detail. A quantized version of the formalism is derived and applied to the generation of Čerenkov and transition radiation as well as atomic decay. The last case suggests a useful generalization of the density of states to the absorptive situation.

  20. Resonant and nonresonant magnetic scattering (invited)

    International Nuclear Information System (INIS)

    McWhan, D.B.; Hastings, J.B.; Kao, C.; Siddons, D.P.

    1992-01-01

    The tunability and the polarization of synchrotron radiation open up new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and they fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin-polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation

  1. Iron absorption studies

    International Nuclear Information System (INIS)

    Ekenved, G.

    1976-01-01

    The main objective of the present work was to study iron absorption from different iron preparations in different types of subjects and under varying therapeutic conditions. The studies were performed with different radioiron isotope techniques and with a serum iron technique. The preparations used were solutions of ferrous sulphate and rapidly-disintegrating tablets containing ferrous sulphate, ferrous fumarate and ferrous carbonate and a slow-release ferrous sulphate tablet of an insoluble matrix type (Duroferon Durules). The serum iron method was evaluated and good correlation was found between the serum iron response and the total amount of iron absorbed after an oral dose of iron given in solution or in tablet form. New technique for studying the in-vivo release properties of tablets was presented. Iron tablets labelled with a radio-isotope were given to healthy subjects. The decline of the radioactivity in the tablets was followed by a profile scanning technique applied to different types of iron tablets. The release of iron from the two types of tablets was shown to be slower in vivo than in vitro. It was found that co-administration of antacids and iron tablets led to a marked reduction in the iron absorption and that these drugs should not be administered sumultaneously. A standardized meal markedly decreased the absorbability of iron from iron tablets. The influence of the meal was more marked with rapidly-disintegrating than with slow-release ferrous sulphate tablets. The absorption from rapidly-disintegrating and slow-release ferrous sulphate tablets was compared under practical clinical conditions during an extended treatment period. The studies were performed in healthy subjects, blood donors and patients with iron deficiency anaemia and it was found that the absorption of iron from the slow-release tablets was significantly better than from the rapidly-disintegrating tablets in all three groups of subjects. (author)

  2. Gamma absorption meter

    International Nuclear Information System (INIS)

    Dincklage, R.D. von.

    1984-01-01

    The absorption meter consists of a radiation source, a trough for the absorbing liquid and a detector. It is characterized by the fact that there is a foil between the detector and the trough, made of a material whose binding energy of the K electrons is a little greater than the energy of the photons emitted by the radiation source. The source of radiation and foil are replaceable. (orig./HP) [de

  3. Total Absorption Spectroscopy

    International Nuclear Information System (INIS)

    Rubio, B.; Gelletly, W.

    2007-01-01

    The problem of determining the distribution of beta decay strength (B(GT)) as a function of excitation energy in the daughter nucleus is discussed. Total Absorption Spectroscopy is shown to provide a way of determining the B(GT) precisely. A brief history of such measurements and a discussion of the advantages and disadvantages of this technique, is followed by examples of two recent studies using the technique. (authors)

  4. A semiclassical study of optical potentials - potential resonances -

    International Nuclear Information System (INIS)

    Lee, S.Y.; Takigawa, N.; Marty, C.

    1977-01-01

    A semiclassical method is used to analyze resonances produced by complex potentials. The absorption plays a central role: when it is not too great, resonances manifest themselves by enhancement of cross sections near π. The reverse is not necessarily true, for instance the anomalous large angle scattering for α-Ca is due to a coherent superposition of many partial waves

  5. Giant dipole resonance by many levels theory

    International Nuclear Information System (INIS)

    Mondaini, R.P.

    1977-01-01

    The many levels theory is applied to photonuclear effect, in particular, in giant dipole resonance. A review about photonuclear dipole absorption, comparing with atomic case is done. The derivation of sum rules; their modifications by introduction of the concepts of effective charges and mass and the Siegert theorem. The experimental distributions are compared with results obtained by curve adjustment. (M.C.K.) [pt

  6. Improving the wide resonance approximation

    International Nuclear Information System (INIS)

    Aboustta, Mohamed A.; Martinez, Aquilino S.

    1999-01-01

    A resonance is considered wide if its practical width, in energy, exceeds the average energy loss per collision, E(1-α A )/2, of the absorbing material. When the mass number, A, is taken infinite, the scattering produces only a change in the direction of motion of the neutron and not in its energy. Based on this assumption, the integral in the slowing-down equation describing the contribution of the resonant absorber is evaluated by taking its limit when α A →1. This work questions the necessity to take such a limit and shows that it is still possible to obtain a simple and more accurate expression for the integral without taking such limit

  7. Improving the wide resonance approximation

    Energy Technology Data Exchange (ETDEWEB)

    Aboustta, Mohamed A.; Martinez, Aquilino S

    1999-03-01

    A resonance is considered wide if its practical width, in energy, exceeds the average energy loss per collision, E(1-{alpha}{sub A})/2, of the absorbing material. When the mass number, A, is taken infinite, the scattering produces only a change in the direction of motion of the neutron and not in its energy. Based on this assumption, the integral in the slowing-down equation describing the contribution of the resonant absorber is evaluated by taking its limit when {alpha}{sub A}{yields}1. This work questions the necessity to take such a limit and shows that it is still possible to obtain a simple and more accurate expression for the integral without taking such limit.

  8. Model for forecasting of monthly average insulation at ground level taking into account the radiation absorption losses crossing atmosphere in the thermal solar applications; Modelo de previsao da insolacao media mensal ao nivel do solo levando em conta a perda por absorcao na atmosfera em aplicacoes solares termicas

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, J.C.; Apolinario, F.R.; Silva, E.P. da [Universidade Estadual de Campinas, SP (Brazil). Lab. de Hidrogenio]. E-mails: joaoc@fem.unicamp.br; rezende@ifi.unicamp.br; lh2ennio@ifi.unicamp.br

    2000-07-01

    The use of the solar energy, for thermal or photovoltaic ends, depends basically on the amount of radiation that reaches the ground in the place where desires to carry through this use, defining the necessary area of the collectors, or panels, that in turn are the main components of the final cost of the system and, therefore, of the viability or not on its use. The incident radiation in the terrestrial surface is minor that one reaches the top of the atmosphere due to the absorption and dispersion factors. The objective of this work is to present a model of forecast the monthly average radiation for ends of use in systems of flat solar collectors for heating water, in the city of Campinas - Sao Paulo, Brazil. This work has been developed by the Hydrogen Laboratory of the Institute of Physics of the UNICAMP, being also used for other applications with solar energy. Based in the radiation data, taken from a local station, a theoretical study was developed to calculate a parameter of loss of radiation when this cross the atmosphere. This Kt loss factor, has basic importance for the knowledge of the effective available energy for use. With this data it is possible to determine, on the basis of the incident radiation in the top of the atmosphere, the value of the radiation on a surface. (author)

  9. Electromagnetic-radiation absorption by water

    Science.gov (United States)

    Lunkenheimer, P.; Emmert, S.; Gulich, R.; Köhler, M.; Wolf, M.; Schwab, M.; Loidl, A.

    2017-12-01

    Why does a microwave oven work? How does biological tissue absorb electromagnetic radiation? Astonishingly, we do not have a definite answer to these simple questions because the microscopic processes governing the absorption of electromagnetic waves by water are largely unclarified. This absorption can be quantified by dielectric loss spectra, which reveal a huge peak at a frequency of the exciting electric field of about 20 GHz and a gradual tailing off toward higher frequencies. The microscopic interpretation of such spectra is highly controversial and various superpositions of relaxation and resonance processes ascribed to single-molecule or molecule-cluster motions have been proposed for their analysis. By combining dielectric, microwave, THz, and far-infrared spectroscopy, here we provide nearly continuous temperature-dependent broadband spectra of water. Moreover, we find that corresponding spectra for aqueous solutions reveal the same features as pure water. However, in contrast to the latter, crystallization in these solutions can be avoided by supercooling. As different spectral contributions tend to disentangle at low temperatures, this enables us to deconvolute them when approaching the glass transition under cooling. We find that the overall spectral development, including the 20 GHz feature (employed for microwave heating), closely resembles the behavior known for common supercooled liquids. Thus water's absorption of electromagnetic waves at room temperature is not unusual but very similar to that of glass-forming liquids at elevated temperatures, deep in the low-viscosity liquid regime, and should be interpreted along similar lines.

  10. Electromagnetic-radiation absorption by water.

    Science.gov (United States)

    Lunkenheimer, P; Emmert, S; Gulich, R; Köhler, M; Wolf, M; Schwab, M; Loidl, A

    2017-12-01

    Why does a microwave oven work? How does biological tissue absorb electromagnetic radiation? Astonishingly, we do not have a definite answer to these simple questions because the microscopic processes governing the absorption of electromagnetic waves by water are largely unclarified. This absorption can be quantified by dielectric loss spectra, which reveal a huge peak at a frequency of the exciting electric field of about 20 GHz and a gradual tailing off toward higher frequencies. The microscopic interpretation of such spectra is highly controversial and various superpositions of relaxation and resonance processes ascribed to single-molecule or molecule-cluster motions have been proposed for their analysis. By combining dielectric, microwave, THz, and far-infrared spectroscopy, here we provide nearly continuous temperature-dependent broadband spectra of water. Moreover, we find that corresponding spectra for aqueous solutions reveal the same features as pure water. However, in contrast to the latter, crystallization in these solutions can be avoided by supercooling. As different spectral contributions tend to disentangle at low temperatures, this enables us to deconvolute them when approaching the glass transition under cooling. We find that the overall spectral development, including the 20 GHz feature (employed for microwave heating), closely resembles the behavior known for common supercooled liquids. Thus water's absorption of electromagnetic waves at room temperature is not unusual but very similar to that of glass-forming liquids at elevated temperatures, deep in the low-viscosity liquid regime, and should be interpreted along similar lines.

  11. Gravitoelectromagnetic resonances

    International Nuclear Information System (INIS)

    Tsagas, Christos G.

    2011-01-01

    The interaction between gravitational and electromagnetic radiation has a rather long research history. It is well known, in particular, that gravity-wave distortions can drive propagating electromagnetic signals. Since forced oscillations provide the natural stage for resonances to occur, gravitoelectromagnetic resonances have been investigated as a means of more efficient gravity-wave detection methods. In this report, we consider the coupling between the Weyl and the Maxwell fields on a Minkowski background, which also applies to astrophysical environments where gravity is weak, at the second perturbative level. We use covariant methods that describe gravitational waves via the transverse component of the shear, instead of pure-tensor metric perturbations. The aim is to calculate the properties of the electromagnetic signal, which emerges from the interaction of its linear counterpart with an incoming gravitational wave. Our analysis shows how the wavelength and the amplitude of the gravitationally driven electromagnetic wave vary with the initial conditions. More specifically, for certain initial data, the amplitude of the induced electromagnetic signal is found to diverge. Analogous, diverging, gravitoelectromagnetic resonances were also reported in cosmology. Given that, we extend our Minkowski space study to cosmology and discuss analogies and differences in the physics and in the phenomenology of the Weyl-Maxwell coupling between the aforementioned two physical environments.

  12. Magnetic resonance annual 1986

    International Nuclear Information System (INIS)

    Kressel, H.Y.

    1986-01-01

    This book contains papers written on magnetic resonance during 1986. Topics include: musculosketetal magnetic resonance imaging; imaging of the spine; magnetic resonance chemical shift imaging; magnetic resonance imaging in the central nervous system; comparison to computed tomography; high resolution magnetic resonance imaging using surface coils; magnetic resonance imaging of the chest; magnetic resonance imaging of the breast; magnetic resonance imaging of the liver; magnetic resonance spectroscopy of neoplasms; blood flow effects in magnetic resonance imaging; and current and potential applications of clinical sodium magnetic resonance imaging

  13. Design principle for absorption enhancement with nanoparticles in thin-film silicon solar cells

    International Nuclear Information System (INIS)

    Xu, Yuanpei; Xuan, Yimin

    2015-01-01

    The use of nanoparticles in solar cells has created many controversies. In this paper, different mechanisms of nanoparticles with different materials with diameters varying from 50 to 200 nm, surface coverage at 5, 20, and 60 %, and different locations are analyzed systematically for efficient light trapping in a thin-film c-Si solar cell. Mie theory and the finite difference time domain method are used for analysis to give a design principle with nanoparticles for the solar cell application. Metals exhibit plasmonic resonances and angular scattering, while dielectrics show anti-reflection and scattering in the incident direction. A table is given to summarize the advantages and disadvantages in different conditions. The silicon absorption enhancement with nanoparticles on top is mainly in the shorter wavelengths below 700 nm, and both Al and SiO 2 nanoparticles with diameter around 100 nm show the most significant enhancement. The silicon absorption enhancement with embedded nanoparticles takes place in the longer wavelengths over 700 nm, and Ag and SiO 2 nanoparticles with larger diameter around 200 nm perform better. However, the light absorbed by Ag nanoparticles will be converted to heat and will lead to decrease in cell efficiency; hence, the choice of metallic nanoparticles in applications to solar cells should be carefully considered. The design principle proposed in this work gives a guideline by choosing reasonable parameters for the different requirements in the application of thin-film solar cells

  14. Michelson interferometer with diffractively-coupled arm resonators in second-order Littrow configuration.

    Science.gov (United States)

    Britzger, Michael; Wimmer, Maximilian H; Khalaidovski, Alexander; Friedrich, Daniel; Kroker, Stefanie; Brückner, Frank; Kley, Ernst-Bernhard; Tünnermann, Andreas; Danzmann, Karsten; Schnabel, Roman

    2012-11-05

    Michelson-type laser-interferometric gravitational-wave (GW) observatories employ very high light powers as well as transmissively-coupled Fabry-Perot arm resonators in order to realize high measurement sensitivities. Due to the absorption in the transmissive optics, high powers lead to thermal lensing and hence to thermal distortions of the laser beam profile, which sets a limit on the maximal light power employable in GW observatories. Here, we propose and realize a Michelson-type laser interferometer with arm resonators whose coupling components are all-reflective second-order Littrow gratings. In principle such gratings allow high finesse values of the resonators but avoid bulk transmission of the laser light and thus the corresponding thermal beam distortion. The gratings used have three diffraction orders, which leads to the creation of a second signal port. We theoretically analyze the signal response of the proposed topology and show that it is equivalent to a conventional Michelson-type interferometer. In our proof-of-principle experiment we generated phase-modulation signals inside the arm resonators and detected them simultaneously at the two signal ports. The sum signal was shown to be equivalent to a single-output-port Michelson interferometer with transmissively-coupled arm cavities, taking into account optical loss. The proposed and demonstrated topology is a possible approach for future all-reflective GW observatory designs.

  15. Donor impurity-related linear and nonlinear optical absorption coefficients in GaAs/Ga{sub 1−x}Al{sub x}As concentric double quantum rings: Effects of geometry, hydrostatic pressure, and aluminum concentration

    Energy Technology Data Exchange (ETDEWEB)

    Baghramyan, H.M.; Barseghyan, M.G.; Kirakosyan, A.A. [Department of Solid State Physics, Yerevan State University, Al. Manookian 1, 0025 Yerevan (Armenia); Restrepo, R.L. [Física Teórica y Aplicada, Escuela de Ingeniería de Antioquia, AA 7516, Medellín (Colombia); Grupo de Materia Condensada-UdeA, Instituto de Física, Facultadde Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21,Medellín (Colombia); Mora-Ramos, M.E. [Grupo de Materia Condensada-UdeA, Instituto de Física, Facultadde Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21,Medellín (Colombia); Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, CP 62209, Cuernavaca, Morelos (Mexico); Duque, C.A., E-mail: cduque@fisica.udea.edu.co [Grupo de Materia Condensada-UdeA, Instituto de Física, Facultadde Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21,Medellín (Colombia)

    2014-01-15

    The linear and nonlinear optical absorption associated with the transition between 1s and 2s states corresponding to the electron-donor-impurity complex in GaAs/Ga{sub 1−x}Al{sub x}As three-dimensional concentric double quantum rings are investigated. Taking into account the combined effects of hydrostatic pressure and the variation of the aluminum concentration, the energies of the ground and first excited s-like states of a donor impurity in such a system have been calculated using the effective mass approximation and a variational method. The energies of these states and the corresponding threshold energy of the optical transitions are examined as functions of hydrostatic pressure, aluminum concentration, radial impurity position, as well as the geometrical dimensions of the structure. The dependencies of the linear, nonlinear and total optical absorption coefficients as functions of the incident photon energy are investigated for different values of those mentioned parameters. It is found that the influences mentioned above lead to either redshifts or blueshifts of the resonant peaks of the optical absorption spectrum. It is particularly discussed the unusual property exhibited by the third-order nonlinear of becoming positive for photon energies below the resonant transition one. It is shown that this phenomenon is associated with the particular features of the system under study, which determine the values of the electric dipole moment matrix elements. -- Highlights: • Intra-band optical absorption associated to impurity states in double quantum rings. • Combined effects of hydrostatic pressure and aluminum concentration are studied. • The influences mentioned above lead to shifts of resonant peaks. • It is discussed an unusual property exhibited by the third-order nonlinear absorption.

  16. Donor impurity-related linear and nonlinear optical absorption coefficients in GaAs/Ga1−xAlxAs concentric double quantum rings: Effects of geometry, hydrostatic pressure, and aluminum concentration

    International Nuclear Information System (INIS)

    Baghramyan, H.M.; Barseghyan, M.G.; Kirakosyan, A.A.; Restrepo, R.L.; Mora-Ramos, M.E.; Duque, C.A.

    2014-01-01

    The linear and nonlinear optical absorption associated with the transition between 1s and 2s states corresponding to the electron-donor-impurity complex in GaAs/Ga 1−x Al x As three-dimensional concentric double quantum rings are investigated. Taking into account the combined effects of hydrostatic pressure and the variation of the aluminum concentration, the energies of the ground and first excited s-like states of a donor impurity in such a system have been calculated using the effective mass approximation and a variational method. The energies of these states and the corresponding threshold energy of the optical transitions are examined as functions of hydrostatic pressure, aluminum concentration, radial impurity position, as well as the geometrical dimensions of the structure. The dependencies of the linear, nonlinear and total optical absorption coefficients as functions of the incident photon energy are investigated for different values of those mentioned parameters. It is found that the influences mentioned above lead to either redshifts or blueshifts of the resonant peaks of the optical absorption spectrum. It is particularly discussed the unusual property exhibited by the third-order nonlinear of becoming positive for photon energies below the resonant transition one. It is shown that this phenomenon is associated with the particular features of the system under study, which determine the values of the electric dipole moment matrix elements. -- Highlights: • Intra-band optical absorption associated to impurity states in double quantum rings. • Combined effects of hydrostatic pressure and aluminum concentration are studied. • The influences mentioned above lead to shifts of resonant peaks. • It is discussed an unusual property exhibited by the third-order nonlinear absorption

  17. Optical absorption in dendrimers

    International Nuclear Information System (INIS)

    Supritz, C.; Engelmann, A.; Reineker, P.

    2004-01-01

    Dendrimers are highly branched molecules, which are expected to be useful, for example, as efficient artificial light harvesting systems in nano-technological applications. There are two different classes of dendrimers: compact dendrimers with constant distance between neighboring branching points throughout the macromolecule and extended dendrimers, where this distance increases from the system periphery to the center. We investigate the linear absorption spectra of these dendrimer types using the Frenkel exciton concept. The electron-phonon interaction is taken into account by introducing a heat bath that interacts with the exciton in a stochastic manner

  18. Rapidly variable relatvistic absorption

    Science.gov (United States)

    Parker, M.; Pinto, C.; Fabian, A.; Lohfink, A.; Buisson, D.; Alston, W.; Jiang, J.

    2017-10-01

    I will present results from the 1.5Ms XMM-Newton observing campaign on the most X-ray variable AGN, IRAS 13224-3809. We find a series of nine absorption lines with a velocity of 0.24c from an ultra-fast outflow. For the first time, we are able to see extremely rapid variability of the UFO features, and can link this to the X-ray variability from the inner accretion disk. We find a clear flux dependence of the outflow features, suggesting that the wind is ionized by increasing X-ray emission.

  19. Breaking the black-body limit with resonant surfaces

    Directory of Open Access Journals (Sweden)

    Valagiannopoulos Constantinos A.

    2017-01-01

    Full Text Available The speed with which electromagnetic energy can be wirelessly transferred from a source to the user is a crucial indicator for the performance of a large number of electronic and photonic devices. We expect that energy transfer can be enhanced using special materials. In this paper, we determine the constituent parameters of a medium which can support theoretically infinite energy concentration close to its boundary; such a material combines properties of Perfectly Matched Layers (PML and Double-Negative (DNG media. It realizes conjugate matching with free space for every possible mode including, most importantly, all evanescent modes; we call this medium Conjugate Matched Layer (CML. Sources located outside such layer deliver power to the conjugate-matched body exceptionally effectively, impressively overcoming the black-body absorption limit which takes into account only propagating waves. We also expand this near-field concept related to the infinitely fast absorption of energy along the air-medium interface to enhance the far-field radiation. This becomes possible with the use of small particles randomly placed along the boundary; the induced currents due to the extremely high-amplitude resonating fields can play the role of emission “vessels”, by sending part of the theoretically unlimited near-field energy far away from the CML structure.

  20. Geospatial Absorption and Regional Effects

    Directory of Open Access Journals (Sweden)

    IOAN MAC

    2009-01-01

    Full Text Available The geospatial absorptions are characterized by a specific complexity both in content and in their phenomenological and spatial manifestation fields. Such processes are differentiated according to their specificity to pre-absorption, absorption or post-absorption. The mechanisms that contribute to absorption are extremely numerous: aggregation, extension, diffusion, substitution, resistivity (resilience, stratification, borrowings, etc. Between these mechanisms frequent relations are established determining an amplification of the process and of its regional effects. The installation of the geographic osmosis phenomenon in a given territory (a place for example leads to a homogenization of the geospatial state and to the installation of the regional homogeneity.

  1. Taking Care of Your Skin

    Science.gov (United States)

    ... Educators Search English Español Taking Care of Your Skin KidsHealth / For Kids / Taking Care of Your Skin ... you're in. Why Be Nice to Your Skin? Like the heart, stomach, and brain, your skin ...

  2. Taking Care of Pressure Sores

    Science.gov (United States)

    ... Tract Infections: Indwelling (Foley) Catheter Taking Care of Pressure Sores [Download this pamphlet: "Taking Care of Pressure Sores" - ( ... may not show up right away. Stages of pressure sores and how to care for them: STAGE ONE ...

  3. Improvement in transmission loss of aircraft double wall with resonators

    Science.gov (United States)

    Sun, Jincai; Shi, Liming; Ye, Xining

    1991-08-01

    A little volume low frequency resonator applicable to double-wall configuration of propeller-driven aircraft was designed on the basis of the principle of Helmholtz resonator. The normal incidence absorption coefficient of the various single resonator has been measured. The agreement between theoretical and experimental results is encouraging. An array of resonators whose resonant frequency at 85 Hz and 160 Hz, respectively, are installed between aircraft double-panel, and it has been shown that transmission loss of the double wall structure with resonators improve 4 dB and 6.5 dB in 1/3rd octave bandwidth at 80 Hz and 160 Hz center frequency, respectively, and 5 dB and 7 dB at resonant frequencies, compared with that of the double wall configuration without resonators.

  4. Evaluation of DNA damage using microwave dielectric absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hirayama, Makoto; Matuo, Youichrou; Izumi, Yoshinobu [Research Institute of Nuclear Engineering, University of Fukui, Fukui (Japan); Sunagawa, Takeyoshi [Fukui University of Technology, Fukui (Japan)

    2016-12-15

    Evaluation of deoxyribonucleic acid (DNA)-strand break is important to elucidate the biological effect of ionizing radiations. The conventional methods for DNA-strand break evaluation have been achieved by Agarose gel electrophoresis and others using an electrical property of DNAs. Such kinds of DNA-strand break evaluation systems can estimate DNA-strand break, according to a molecular weight of DNAs. However, the conventional method needs pre-treatment of the sample and a relatively long period for analysis. They do not have enough sensitivity to detect the strand break products in the low-dose region. The sample is water, methanol and plasmid DNA solution. The plasmid DNA pUC118 was multiplied by using Escherichia coli JM109 competent cells. The resonance frequency and Q-value were measured by means of microwave dielectric absorption spectroscopy. When a sample is located at a center of the electric field, resonance curve of the frequency that existed as a standing wave is disturbed. As a result, the perturbation effect to perform a resonance with different frequency is adopted. The resonance frequency shifted to higher frequency with an increase in a concentration of methanol as the model of the biological material, and the Q-value decreased. The absorption peak in microwave power spectrum of the double-strand break plasmid DNA shifted from the non-damaged plasmid DNA. Moreover, the sharpness of absorption peak changed resulting in change in Q-value. We confirmed that a resonance frequency shifted to higher frequency with an increase in concentration of the plasmid DNA. We developed a new technique for an evaluation of DNA damage. In this paper, we report the evaluation method of DNA damage using microwave dielectric absorption spectroscopy.

  5. Evaluation of DNA damage using microwave dielectric absorption spectroscopy

    International Nuclear Information System (INIS)

    Hirayama, Makoto; Matuo, Youichrou; Izumi, Yoshinobu; Sunagawa, Takeyoshi

    2016-01-01

    Evaluation of deoxyribonucleic acid (DNA)-strand break is important to elucidate the biological effect of ionizing radiations. The conventional methods for DNA-strand break evaluation have been achieved by Agarose gel electrophoresis and others using an electrical property of DNAs. Such kinds of DNA-strand break evaluation systems can estimate DNA-strand break, according to a molecular weight of DNAs. However, the conventional method needs pre-treatment of the sample and a relatively long period for analysis. They do not have enough sensitivity to detect the strand break products in the low-dose region. The sample is water, methanol and plasmid DNA solution. The plasmid DNA pUC118 was multiplied by using Escherichia coli JM109 competent cells. The resonance frequency and Q-value were measured by means of microwave dielectric absorption spectroscopy. When a sample is located at a center of the electric field, resonance curve of the frequency that existed as a standing wave is disturbed. As a result, the perturbation effect to perform a resonance with different frequency is adopted. The resonance frequency shifted to higher frequency with an increase in a concentration of methanol as the model of the biological material, and the Q-value decreased. The absorption peak in microwave power spectrum of the double-strand break plasmid DNA shifted from the non-damaged plasmid DNA. Moreover, the sharpness of absorption peak changed resulting in change in Q-value. We confirmed that a resonance frequency shifted to higher frequency with an increase in concentration of the plasmid DNA. We developed a new technique for an evaluation of DNA damage. In this paper, we report the evaluation method of DNA damage using microwave dielectric absorption spectroscopy

  6. 1004 RESONANCE November 2013

    Indian Academy of Sciences (India)

    IAS Admin

    1004. RESONANCE │ November 2013. Page 2. 1005. RESONANCE │ November 2013. Page 3. 1006. RESONANCE │ November 2013. Page 4. 1007. RESONANCE │ November 2013. Page 5. 1008. RESONANCE │ November 2013. Page 6. 1009. RESONANCE │ November 2013. Page 7. 1010. RESONANCE ...

  7. Even order snake resonances

    International Nuclear Information System (INIS)

    Lee, S.Y.

    1993-01-01

    We found that the perturbed spin tune due to the imperfection resonance plays an important role in beam depolarization at snake resonances. We also found that even order snake resonances exist in the overlapping intrinsic and imperfection resonances. Due to the perturbed spin tune shift of imperfection resonances, each snake resonance splits into two

  8. Microwave dielectric absorption spectroscopy aiming at novel dosimetry using DNAs

    Energy Technology Data Exchange (ETDEWEB)

    Izumi, Yoshinobu; Hirayama, Makoto; Matuo, Youichirou [Research Institute of Nuclear Engineering, University of Fukui, Fukui (Japan); Sunagawa, Takeyoshi [Fukui University of Technology, Fukui (Japan)

    2017-03-15

    We are developing L-band and S-band microwave dielectric absorption systems aiming novel dosimetry using DNAs, such as plasmid DNA and genomic DNA, and microwave technology. Each system is composed of a cavity resonator, analog signal generator, circulator, power meter, and oscilloscope. Since the cavity resonator is sensitive to temperature change, we have made great efforts to prevent the fluctuation of temperature. We have developed software for controlling and measurement. By using this system, we can measure the resonance frequency, f, and ΔQ (Q is a dimensionless parameter that describes how under-damped an oscillator or resonator is, and characterizes a resonator’s bandwidth relative to its center frequency) within about 3 minutes with high accuracy. This system will be expected to be applicable to DNAs evaluations and to novel dosimetric system.

  9. Medication absorption for patients with an ileostomy.

    Science.gov (United States)

    Moore, Susan

    The Association of Stoma Care Nurses UK (2013) has stressed that it is the role of the stoma care nurse to provide education to patients, carers, prescribers and other nurses. This includes the area of medication management. Ensuring patients with an ileostomy receive their medication in a form they can absorb is of importance to every stoma care nurse. Prescribing for patients with a stoma calls for special care. Each patient with an ileostomy requires assessment of their medication regimen for the purpose of identifying potential medical absorption issues. However, from an extensive literature search, it is evident that there is very little literature published on this subject. This article looks at the considerations to take into account when prescribing medication for ileostomy patients, and examines the results of a clinical audit on medication prescribers' knowledge of the impact of ileostomy formation on the absorption of medication.

  10. Optomechanically induced absorption in parity-time-symmetric optomechanical systems

    Science.gov (United States)

    Zhang, X. Y.; Guo, Y. Q.; Pei, P.; Yi, X. X.

    2017-06-01

    We explore the optomechanically induced absorption (OMIA) in a parity-time- (PT -) symmetric optomechanical system (OMS). By numerically calculating the Lyapunov exponents, we find out the stability border of the PT -symmetric OMS. The results show that in the PT -symmetric phase the system can be either stable or unstable depending on the coupling constant and the decay rate. In the PT -symmetric broken phase the system can have a stable state only for small gain rates. By calculating the transmission rate of the probe field, we find that there is an inverted optomechanically induced transparency (OMIT) at δ =-ωM and an OMIA at δ =ωM for the PT -symmetric optomechanical system. At each side of δ =-ωM there is an absorption window due to the resonance absorption of the two generated supermodes. Comparing with the case of optomechanics coupled to a passive cavity, we find that the active cavity can enhance the resonance absorption. The absorption rate at δ =ωM increases as the coupling strength between the two cavities increases. Our work provides us with a promising platform for controlling light propagation and light manipulation in terms of PT symmetry, which might have potential applications in quantum information processing and quantum optical devices.

  11. Absorption Mode FT-ICR Mass Spectrometry Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Donald F.; Kilgour, David P.; Konijnenburg, Marco; O' Connor, Peter B.; Heeren, Ronald M.

    2013-12-03

    Fourier transform ion cyclotron resonance mass spectrometry offers the highest mass resolving power for molecular imaging experiments. This high mass resolving power ensures that closely spaced peaks at the same nominal mass are resolved for proper image generation. Typically higher magnetic fields are used to increase mass resolving power. However, a gain in mass resolving power can also be realized by phase correction of the data for absorption mode display. In addition to mass resolving power, absorption mode offers higher mass accuracy and signal-to-noise ratio over the conventional magnitude mode. Here we present the first use of absorption mode for Fourier transform ion cyclotron resonance mass spectrometry imaging. The Autophaser algorithm is used to phase correct each spectrum (pixel) in the image and then these parameters are used by the Chameleon work-flow based data processing software to generate absorption mode ?Datacubes? for image and spectral viewing. Absorption mode reveals new mass and spatial features that are not resolved in magnitude mode and results in improved selected ion image contrast.

  12. Linear and nonlinear optical absorption coefficients in GaAs/Ga1−xAlxAs concentric double quantum rings: Effects of hydrostatic pressure and aluminum concentration

    International Nuclear Information System (INIS)

    Baghramyan, H.M.; Barseghyan, M.G.; Kirakosyan, A.A.; Restrepo, R.L.; Duque, C.A.

    2013-01-01

    The linear and nonlinear intra-band optical absorption coefficients in GaAs/Ga 1−x Al x As two-dimensional concentric double quantum rings are investigated. Taking into account the combined effects of hydrostatic pressure and aluminum concentration the energies of the ground (n=1,l=0) and the first excited state (n=2,l=1) have been found using the effective mass approximation and the transfer matrix formalism. The energies of these states and the corresponding threshold energy of the intra-band optical transitions are examined as a function of hydrostatic pressure and aluminum concentration for different sizes of the structure. We also investigated the dependencies of the linear, nonlinear, and total optical absorption coefficients as functions of the incident photon energy for different values of hydrostatic pressure, aluminum concentration, sizes of the structure, and incident optical intensity. Its is found that the effects of the hydrostatic pressure and the aluminum concentration lead to a shifting of the resonant peaks of the intra-band optical spectrum. - Highlights: ► Linear and nonlinear intra-band absorption in quantum rings. ► Threshold energy strongly depends on the hydrostatic pressure. ► Threshold energy strongly depends on the stoichiometry and sizes of structure. ► Optical absorption is affected by the incident optical intensity.

  13. Time evolution of absorption process in nonlinear metallic photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Mahi R.; Hatef, Ali [Department of Physics and Astronomy, University of Western Ontario, London (Canada)

    2009-05-15

    The time evolution of the absorption coefficient in metallic photonic crystals has been studied numerically. These crystals are made from metallic spheres which are arranged periodically in air. The refractive index of the metallic spheres depends on the plasma frequency. Probe and pump fields are applied to monitor the absorption process. Ensembles of three-level particles are embedded in the crystal. Nanoparticles are interacting with the metallic crystals via the electron-photon interaction. It is found that when the resonance states lie away from the band edges system goes to transparent state. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Broadband infrared absorption enhancement by electroless-deposited silver nanoparticles

    DEFF Research Database (Denmark)

    Gritti, Claudia; Raza, Søren; Kadkhodazadeh, Shima

    2017-01-01

    Decorating semiconductor surfaces with plasmonic nanoparticles (NPs) is considered a viable solution for enhancing the absorptive properties of photovoltaic and photodetecting devices. We propose to deposit silver NPs on top of a semiconductor wafer by a cheap and fast electroless plating technique......, which points to the possible applications of such deposition method for harvesting photons in nanophotonics and photovoltaics. The broadband absorption is a consequence of the resonant behavior of particles with different shapes and sizes, which strongly localize the incident light at the interface...

  15. Investigations of mechanism of laser radiation absorption at PALS

    Czech Academy of Sciences Publication Activity Database

    Kalinowska, Z.; Kasperczuk, A.; Pisarczyk, T.; Chodukowski, T.; Gus’kov, S.Yu.; Demchenko, N. N.; Ullschmied, Jiří; Krouský, Eduard; Pfeifer, Miroslav; Skála, Jiří

    2012-01-01

    Roč. 57, č. 2 (2012), s. 227-230 ISSN 0029-5922. [International Conference on Research and Applications of Plasmas (PLASMA)2011. Warsaw, 12.09.2011-16.09.2011] R&D Projects: GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z20430508 Keywords : collisional absorption * crater volume * electron density distribution * interferometry * iodine laser * resonance absorption * Laser radiation * inverse bremsstrahlung * laser interferometry * PALS laser Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.507, year: 2012 http://www.nukleonika.pl/www/back/full/vol57_2012/v57n2p227f.pdf

  16. Theoretical calculation of saturated absorption for multilevel atoms

    International Nuclear Information System (INIS)

    O'Kane, T.J.; Scholten, R.E.; Farrell, P.M.

    1998-01-01

    We present the first theoretical saturated absorption spectra for general multi-level atoms, using a model based on extensions of the optical Bloch equations, and using Monte Carlo averaging of the absorption of individual atoms with random trajectories through a standing wave. We are for the first time able to accurately predict the merging of hyperfine and cross-over resonances due to intensity dependent phenomena such as power broadening. Results for 20-level sodium and 24-level rubidium models are presented and compared to experiment, demonstrating excellent agreement

  17. Resonant laser printing of structural colors on high-index dielectric metasurfaces

    DEFF Research Database (Denmark)

    Zhu, Xiaolong; Yan, Wei; Levy, Uriel

    2017-01-01

    -dependent resonances. Strong on-resonance energy absorption under pulsed laser irradiation locally elevates the lattice temperature (exceeding 1200 K) in an ultrashort time scale (1 ns). This forms the basis for resonant laser printing, where rapid melting allows for surface energy-driven morphology changes...

  18. Perfect absorption in nanotextured thin films via Anderson-localized photon modes

    Science.gov (United States)

    Aeschlimann, Martin; Brixner, Tobias; Differt, Dominik; Heinzmann, Ulrich; Hensen, Matthias; Kramer, Christian; Lükermann, Florian; Melchior, Pascal; Pfeiffer, Walter; Piecuch, Martin; Schneider, Christian; Stiebig, Helmut; Strüber, Christian; Thielen, Philip

    2015-10-01

    The enhancement of light absorption in absorber layers is crucial in a number of applications, including photovoltaics and thermoelectrics. The efficient use of natural resources and physical constraints such as limited charge extraction in photovoltaic devices require thin but efficient absorbers. Among the many different strategies used, light diffraction and light localization at randomly nanotextured interfaces have been proposed to improve absorption. Although already exploited in commercial devices, the enhancement mechanism for devices with nanotextured interfaces is still subject to debate. Using coherent two-dimensional nanoscopy and coherent light scattering, we demonstrate the existence of localized photonic states in nanotextured amorphous silicon layers as used in commercial thin-film solar cells. Resonant absorption in these states accounts for the enhanced absorption in the long-wavelength cutoff region. Our observations establish that Anderson localization—that is, strong localization—is a highly efficient resonant absorption enhancement mechanism offering interesting opportunities for the design of efficient future absorber layers.

  19. Far-Infrared Absorption of PbSe Nanorods

    KAUST Repository

    Hyun, Byung-Ryool

    2011-07-13

    Measurements of the far-infrared absorption spectra of PbSe nanocrystals and nanorods are presented. As the aspect ratio of the nanorods increases, the Fröhlich sphere resonance splits into two peaks. We analyze this splitting with a classical electrostatic model, which is based on the dielectric function of bulk PbSe but without any free-carrier contribution. Good agreement between the measured and calculated spectra indicates that resonances in the local field factors underlie the measured spectra. © 2011 American Chemical Society.

  20. Optical absorptions of an exciton in a quantum ring: Effect of the repulsive core

    International Nuclear Information System (INIS)

    Xie, Wenfang

    2013-01-01

    We study the optical absorptions of an exciton in a quantum ring. The quantum ring is described as a circular quantum dot with a repulsive core. The advantage of our methodology is that one can investigate the influence of the repulsive core by varying two parameters in the confinement potential. The linear, third-order nonlinear and total optical absorption coefficients have been examined with the change of the confinement potential. The results show that the optical absorptions are strongly affected by the repulsive core. Moreover, the repulsive core can influence the oscillation in the resonant peak of the absorption coefficients.

  1. Enhanced absorption of graphene in the visible region by use of plasmonic nanostructures

    DEFF Research Database (Denmark)

    Hashemi, Mahdieh; Farzad, Mahmood Hosseini; Mortensen, N. Asger

    2013-01-01

    Low absorption of graphene in the visible range of the spectrum makes it difficult to uniquely benefit from this material in ultra-fast optoelectronic applications. We numerically propose to utilize patterned metallic nanostructures to increase light absorption in single-layer graphene. Simulation...... results show that excitation of surface plasmon resonances in the metallic nanostructures significantly enhances the local electromagnetic field near the graphene layer, therefore leading to a dramatic enhancement of the absorption in the graphene layer itself. Broadband high optical absorption can...

  2. Linear theory of microwave absortion in fusion plasmas. A study of the electron cyclotron resonance and its particularization to a helical axis device for magnetic confinement

    International Nuclear Information System (INIS)

    Castejon M, F.

    1989-01-01

    The study of the Linear Theory microwave propagation and absorption in the the frequency range of electron cyclotron resonance, in a magnetized plasma, is developed. This study is particularized to the flexible heliac TJ-II, whose main characteristics are dsetailed in a memory chapter, as an interesting case example for its peculiar magnetic configuration. As a preliminary phase, a cold plasma model is useds to analyze the resonance accessibility and the approximated density limits which will be obtainable in each electron cyclotron resonance harmonic. This analysis was used to find the suitable positions for the microwave injection in TJ-II. An analytical weakly relativistic model for the dielectric tensor is developed, valid for oblique propagation, that takes account of the effect of superthermal electrons. Second order Larmor radius effects are included, so that the Quasi-Electrostatic branch of X mode can be studied. A numerical study is then presented on the absorption properties of TJ-II. Since the TJ-II geometry is complex and its magnetic field distribution is very different from that of a tokamak, ray tracing calculations are necessary to consider refraction effects. The ray tracing codse RAYS, developed in the Oak Ridge National Laboratory (U.S.A.), was take and adapted to the helical magnetic configuration of the TJ-II. The absorption model described above was then included in RAYS. For completeness, an introduction to the Quasi Linear Theory, natural prolongation of this work, is included at the end of the memory, ands the effects of taking into account the quasi linear evolution of the distribution function are described. (Author)

  3. SAM revisited: uniform semiclassical approximation with absorption

    International Nuclear Information System (INIS)

    Hussein, M.S.; Pato, M.P.

    1986-01-01

    The uniform semiclassical approximation is modified to take into account strong absorption. The resulting theory, very similar to the one developed by Frahn and Gross is used to discuss heavy-ion elastic scattering at intermediate energies. The theory permits a reasonably unambiguos separation of refractive and diffractive effects. The systems 12 C+ 12 C and 12 C+ 16 O, which seem to exhibit a remnant of a nuclear rainbow at E=20 Mev/N, are analysed with theory which is built directly on a model for the S-matrix. Simple relations between the fit S-matrix and the underlying complex potential are derived. (Author) [pt

  4. Atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Haswell, S.J.

    1991-01-01

    Atomic absorption spectroscopy is now well established and widely used technique for the determination of trace and major elements in a wide range analyte types. There have been many advances in the atomic spectroscopy over the last decade and for this reason and to meet the demand, it was felt that there was a need for an updated book. Whilst interest in instrumental design has tended to dominate the minds of the spectrocopist, the analyst concerned with obtaining reliable and representative data, in diverse areas of application, has been diligently modifying and developing sample treatment and instrumental introduction techniques. Such methodology is de fundamental part of analysis and form the basis of the fourteen application chapters of this book. The text focuses in the main on AAS; however, the sample handling techniques described are in many cases equally applicable to ICP-OES and ICP-MS analysis. (author). refs.; figs.; tabs

  5. Atomic absorption spectrophotometer

    International Nuclear Information System (INIS)

    Stockdale, T. J.

    1985-01-01

    In atomic absorption spectrophotometer, a reference path may be provided for radiation which excludes the flame. This radiation provides a signal from a detector which varies only with the instrumental drift produced by variations in the radiation source brightness and by variations in detector gain. The signal can be used to compensate for drift in other signals received through a sample path including the flame. In the present invention, radiation passes through the sample path continuously during measurement, and only through the reference path between sample measurements. Movable mirrors shift the radiation between the paths upon externally applied commands. Conveniently, the reference path measurement is made while the flame is stabilized during the change between samples. The reference path measurements are stored and used to correct for drift

  6. Analyzing Water's Optical Absorption

    Science.gov (United States)

    2002-01-01

    A cooperative agreement between World Precision Instruments (WPI), Inc., and Stennis Space Center has led the UltraPath(TM) device, which provides a more efficient method for analyzing the optical absorption of water samples at sea. UltraPath is a unique, high-performance absorbance spectrophotometer with user-selectable light path lengths. It is an ideal tool for any study requiring precise and highly sensitive spectroscopic determination of analytes, either in the laboratory or the field. As a low-cost, rugged, and portable system capable of high- sensitivity measurements in widely divergent waters, UltraPath will help scientists examine the role that coastal ocean environments play in the global carbon cycle. UltraPath(TM) is a trademark of World Precision Instruments, Inc. LWCC(TM) is a trademark of World Precision Instruments, Inc.

  7. Microwave absorptions of ultrathin conductive films and designs of frequency-independent ultrathin absorbers

    International Nuclear Information System (INIS)

    Li, Sucheng; Anwar, Shahzad; Lu, Weixin; Hang, Zhi Hong; Hou, Bo; Shen, Mingrong; Wang, Chin-Hua

    2014-01-01

    We study the absorption properties of ultrathin conductive films in the microwave regime, and find a moderate absorption effect which gives rise to maximal absorbance 50% if the sheet (square) resistance of the film meets an impedance matching condition. The maximal absorption exhibits a frequency-independent feature and takes place on an extremely subwavelength scale, the film thickness. As a realistic instance, ∼5 nm thick Au film is predicted to achieve the optimal absorption. In addition, a methodology based on metallic mesh structure is proposed to design the frequency-independent ultrathin absorbers. We perform a design of such absorbers with 50% absorption, which is verified by numerical simulations

  8. Absorption spectrum of a two-level atom in a bad cavity with injected squeezed vacuum

    Science.gov (United States)

    Zhou, Peng; Swain, S.

    1996-02-01

    We study the absorption spectrum of a coherently driven two-level atom interacting with a resonant cavity mode which is coupled to a broadband squeezed vacuum through its input-output mirror in the bad cavity limit. We study the modification of the two-photon correlation strength of the injected squeezed vacuum inside the cavity, and show that the equations describing probe absorption in the cavity environment are formally identical to these in free space, but with modified parameters describing the squeezed vacuum. The two photon correlations induced by the squeezed vacuum are always weaker than in free space. We pay particular attention to the spectral behaviour at line centre in the region of intermediate trength driving intensities, where anomalous spectral features such as hole-burning and dispersive profiles are displayed. These unusual spectral features are very sensitive to the squeezing phase and the Rabi frequency of the driving field. We also derive the threshold value of the Rabi frequency which gives rise to the transparency of the probe beam at the driving frequency. When the Rabi frequency is less than the threshold value, the probe beam is absorbed, whilst the probe beam is amplified (without population inversion under certain conditions) when the Rabi frequency is larger than this threshold. The anomalous spectral features all take place in the vicinity of the critical point dividing the different dynamical regimes, probe absorption and amplification, of the atomic radiation. The physical origin of the strong amplification without population inversion, and the feasibility of observing it, are discussed.

  9. Preparation for propagation and absorption experiments in MTX

    International Nuclear Information System (INIS)

    Byers, J.A.; Cohen, R.H.; Fenstermacher, M.E.; Hooper, E.B.; Meassick, S.; Rognlien, T.D.; Smith, G.R.; Stallard, B.W.

    1989-04-01

    Preparatory calculations of microwave transmission through the MTX access duct, propagation of the waves through the plasma and the resulting power deposition profile on a calorimeter located on the tokamak inside wall have been performed. The microwave transmission calculations include the relative phase slippage of waveguide modes in the duct to determine the spatial structure of the wavefront at the duct exist. Ray-tracing calculations show substantial spreading of the beam in the poloidal direction at densities above 1.5 /times/ 10 20 m/sup /minus/3/, well within the range of the experiments. Initial experiments with low or high toroidal field (cyclotron resonance outside the plasma) will investigate both diffraction and refraction effects, without absorption. Estimates of the fractional absorption of the beam in the initial experiments with the cyclotron resonance at the plasma axis have also been made. 4 refs., 3 figs

  10. Atomic absorption spectrophotometry in perspective

    International Nuclear Information System (INIS)

    Soffiantini, V.

    1981-01-01

    Atomic absorption spectrophotometry is essentially an analytical technique used for quantitative trace metal analysis in a variety of materials. The speed and specificity of the technique is its greatest advantage over other analytical techniques. What atomic absorption spectrophotometry can and cannot do and its advantages and disadvantages are discussed, a summary of operating instructions are given, as well as a summary of analytical interferences. The applications of atomic absorption spectrophotometry are also shortly discussed

  11. Nonlinear effects in collective absorption

    International Nuclear Information System (INIS)

    Uenoyama, Takeshi; Mima, Kunioki; Watanabe, Tsuguhiro.

    1981-01-01

    The collective absorption of high intensity laser radiation is analyzed numerically. Density profile modification due to the ponderomotive force associating laser radiation and the excited electron plasma waves is self-consistently taken into account, and the intensity dependences of the absorption efficiency are obtained. In the high intensity regime, the absorption efficiency is found to be strongly enhanced in the plasma without flow, but reduced with supersonic flow. (author)

  12. Take Charge. Take the Test. "You Know" PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    As part of the Take Charge. Take the Test. campaign, this 60 second PSA encourages African American women to get tested for HIV. Locations for a free HIV test can be found by visiting hivtest.org/takecharge or calling 1-800-CDC-INFO (1-800-232-4636).

  13. Ferromagnetic resonance characterization of nano-FePt by electron spin resonance

    CSIR Research Space (South Africa)

    Nkosi, SS

    2013-01-01

    Full Text Available Electron spin resonance (ESR) measurements at room temperature and X-band microwave frequency were performed on highly crystalline FePt system thin films. Fairly high DC static magnetic field absorption of about 300 mT was observed in these films...

  14. Proton nuclear magnetic resonance and spectrophotometric studies of nickel(II)-iron(II) hybrid hemoglobins

    International Nuclear Information System (INIS)

    Shibayama, N.; Inubushi, T.; Morimoto, H.; Yonetani, T.

    1987-01-01

    Ni(II)-Fe(II) hybrid hemoglobins, α(Fe) 2 β(Ni) 2 and α(Ni) 2 β(Fe) 2 , have been characterized by proton nuclear magnetic resonance with Ni(II) protoporphyrin IX (Ni-PP) incorporated in apoprotein, which serves as a permanent deoxyheme. α(Fe) 2 β(Ni) 2 , α(Ni) 2 β(Fe) 2 , and NiHb commonly show exchangeable proton resonances at 11 and 14 ppm, due to hydrogen-bonded protons in a deoxy-like structure. Upon binding of carbon monoxide (CO) to α(Fe) 2 β(Ni) 2 , these resonances disappear at pH 6.5 to pH 8.5. On the other hand, the complementary hybrid α(Ni) 2 β(Fe-CO) 2 showed the 11 and 14 ppm resonances at low pH. Upon raising pH, the intensities of both resonances are reduced, although these changes are not synchronized. Electronic absorption spectra and hyperfine-shifted proton resonances indicate that the ligation of CO in the β(Fe) subunits induced changes in the coordination and spin states of Ni-PP in the α subunits. In a deoxy-like structure, the coordination of Ni-PP in the α subunits is predominantly in a low-spin (S = 0) four-coordination state, whereas in an oxy-like structure the contribution of a high-spin (S = 1) five-coordination state markedly increased. Ni-PP in the β subunits always takes a high-spin five-coordination state regardless of solution conditions and the state of ligation in the partner α(Fe) subunits. In the β(Ni) subunits, a significant downfield shift of the proximal histidyl N/sub δ/H resonance and a change in the absorption spectrum of Ni-PP were detected, upon changing the quaternary structure of the hybrid. The chemical shifts were analyzed in terms of the E11-Val methyls vs. the porphyrin rings in hybrid Hbs

  15. X-ray Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

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

  16. Absorption dynamics and delay time in complex potentials

    Science.gov (United States)

    Villavicencio, Jorge; Romo, Roberto; Hernández-Maldonado, Alberto

    2018-05-01

    The dynamics of absorption is analyzed by using an exactly solvable model that deals with an analytical solution to Schrödinger’s equation for cutoff initial plane waves incident on a complex absorbing potential. A dynamical absorption coefficient which allows us to explore the dynamical loss of particles from the transient to the stationary regime is derived. We find that the absorption process is characterized by the emission of a series of damped periodic pulses in time domain, associated with damped Rabi-type oscillations with a characteristic frequency, ω = (E + ε)/ℏ, where E is the energy of the incident waves and ‑ε is energy of the quasidiscrete state of the system induced by the absorptive part of the Hamiltonian; the width γ of this resonance governs the amplitude of the pulses. The resemblance of the time-dependent absorption coefficient with a real decay process is discussed, in particular the transition from exponential to nonexponential regimes, a well-known feature of quantum decay. We have also analyzed the effect of the absorptive part of the potential on the dynamical delay time, which behaves differently from the one observed in attractive real delta potentials, exhibiting two regimes: time advance and time delay.

  17. Energy absorption build-up factors in teeth

    International Nuclear Information System (INIS)

    Manjunatha, H.C.; Rudraswamy, B.

    2012-01-01

    Geometric progression fitting method has been used to compute energy absorption build-up factor of teeth [enamel outer surface, enamel middle, enamel dentin junction towards enamel, enamel dentin junction towards dentin, dentin middle and dentin inner surface] for wide energy range (0.015-15 MeV) up to the penetration depth of 40 mean free path. The dependence of energy absorption build-up factor on incident photon energy, penetration depth, electron density and effective atomic number has also been studied. The energy absorption build-up factors increases with the penetration depth and electron density of teeth. So that the degree of violation of Lambert-Beer (I = I 0 e -μt ) law is less for least penetration depth and electron density. The energy absorption build-up factors for different regions of teeth are not same hence the energy absorbed by the different regions of teeth is not uniform which depends on the composition of the medium. The relative dose of gamma in different regions of teeth is also estimated. Dosimetric implication of energy absorption build-up factor in teeth has also been discussed. The estimated absorption build up factors in different regions of teeth may be useful in the electron spin resonance dosimetry. (author)

  18. Applied neutron resonance theory

    International Nuclear Information System (INIS)

    Froehner, F.H.

    1980-01-01

    Utilisation of resonance theory in basic and applications-oriented neutron cross section work is reviewed. The technically important resonance formalisms, principal concepts and methods as well as representative computer programs for resonance parameter extraction from measured data, evaluation of resonance data, calculation of Doppler-broadened cross sections and estimation of level-statistical quantities from resonance parameters are described. (author)

  19. Applied neutron resonance theory

    International Nuclear Information System (INIS)

    Froehner, F.H.

    1978-07-01

    Utilisation of resonance theory in basic and applications-oriented neutron cross section work is reviewed. The technically important resonance formalisms, principal concepts and methods as well as representative computer programs for resonance parameter extraction from measured data, evaluation of resonance data, calculation of Doppler-broadened cross sections and estimation of level-statistical quantities from resonance parameters are described. (orig.) [de

  20. Enhanced energy storage in chaotic optical resonators

    KAUST Repository

    Liu, Changxu; Di Falco, Andrea; Molinari, Diego P.; Khan, Yasser; Ooi, Boon S.; Krauss, Thomas F.; Fratalocchi, Andrea

    2013-01-01

    Chaos is a phenomenon that occurs in many aspects of contemporary science. In classical dynamics, chaos is defined as a hypersensitivity to initial conditions. The presence of chaos is often unwanted, as it introduces unpredictability, which makes it difficult to predict or explain experimental results. Conversely, we demonstrate here how chaos can be used to enhance the ability of an optical resonator to store energy. We combine analytic theory with ab initio simulations and experiments in photonic-crystal resonators to show that a chaotic resonator can store six times more energy than its classical counterpart of the same volume. We explain the observed increase by considering the equipartition of energy among all degrees of freedom of the chaotic resonator (that is, the cavity modes) and discover a convergence of their lifetimes towards a single value. A compelling illustration of the theory is provided by enhanced absorption in deformed polystyrene microspheres. © 2013 Macmillan Publishers Limited. All rights reserved.

  1. Enhanced energy storage in chaotic optical resonators

    KAUST Repository

    Liu, Changxu

    2013-05-05

    Chaos is a phenomenon that occurs in many aspects of contemporary science. In classical dynamics, chaos is defined as a hypersensitivity to initial conditions. The presence of chaos is often unwanted, as it introduces unpredictability, which makes it difficult to predict or explain experimental results. Conversely, we demonstrate here how chaos can be used to enhance the ability of an optical resonator to store energy. We combine analytic theory with ab initio simulations and experiments in photonic-crystal resonators to show that a chaotic resonator can store six times more energy than its classical counterpart of the same volume. We explain the observed increase by considering the equipartition of energy among all degrees of freedom of the chaotic resonator (that is, the cavity modes) and discover a convergence of their lifetimes towards a single value. A compelling illustration of the theory is provided by enhanced absorption in deformed polystyrene microspheres. © 2013 Macmillan Publishers Limited. All rights reserved.

  2. Optical absorption in a degenerate Bose-Einstein gas

    International Nuclear Information System (INIS)

    Yip, S.K.

    2002-01-01

    We develop a theory on optical absorption in a dilute Bose-Einstein gas at low temperatures. This theory is motivated by the Bogoliubov theory of elementary excitations for this system, and takes into account explicitly the modification of the nature and dispersion of elementary excitations due to Bose-Einstein condensation. Our results show important differences from existing theories

  3. Galactic absorption line coronae

    International Nuclear Information System (INIS)

    Bregman, J.N.

    1981-01-01

    We have investigated whether gaseous coronae around galaxies rise to the absorption systems seen in quasar spectra. In our model, gas originally located in the disk is heated to the million degree range and rises to surround the galaxy; the gas remains bound to the galaxy. Optically thin radiative cooling drives a thermal instability in the hot gas which causes cool clouds (T 4 K) to condense out of the corona. These clouds, which follow ballistic trajectories back to the disk, are the absorption sites. A two-dimensional hydrodynamic code with radiative cooling was used to study the dynamics and thermodynamics of the corona as well as the position rate at which clouds form. Coupled to the code is a galaxy with two mass components, a disk (approx.10 11 M/sub sun/) and a dark halo (approx.10 12 M/sub sun/). In a model where the temperature at the base of the corona (in the disk) is 3 x 10 6 K, absorbing gas of column density NL> or approx. =10 18 cm 2 extends radially to 100 kpc (face-on orientation) and vertically to 60 Kpc (edge-on orientation). The total mass of gas required here (coronal plus cloud gas) is 1.4 x 10 10 M/sub sun/, while the minimum supernova heating rate is one supernova per 27 years. In two other models (base coronal temperatures of 0.50 x 10 6 K and 1 x 10 6 K), coronal gas rises from an extended gaseous disk (in the previous model, the gas comes from a typical gaseous disk approximately 15 kpc in extent). Here, column densities of 10 19 cm -2 out to a radius of 70 kpc (face-on orientation) are achieved with a total gas mass of 1.7 x 10 9 M/sub direct-product/ and 2.0 x 10 9 M/sub sun/ and minimum heating rates of approximately one supernova per 170 years and one supernova per 60 years

  4. Coherent virtual absorption for discretized light

    Science.gov (United States)

    Longhi, S.

    2018-05-01

    Coherent virtual absorption (CVA) is a recently-introduced phenomenon for which exponentially growing waves incident onto a conservative optical medium are neither reflected nor transmitted, at least transiently. CVA has been associated to complex zeros of the scattering matrix and can be regarded as the time reversal of the decay process of a quasi-mode sustained by the optical medium. Here we consider CVA for discretized light transport in coupled resonator optical waveguides or waveguide arrays and show that a distinct kind of CVA, which is not related to complex zero excitation of quasi-modes, can be observed. This result suggests that scattering matrix analysis can not fully capture CVA phenomena.

  5. Resonant-spin-ordering of vortex cores in interacting mesomagnets

    Science.gov (United States)

    Jain, Shikha

    2013-03-01

    The magnetic system of interacting vortex-state elements have a dynamically reconfigurable ground state characterized by different relative polarities and chiralities of the individual disks; and have a corresponding dynamically controlled spectrum of collective excitation modes that determine the microwave absorption of the crystal. The development of effective methods for dynamic control of the ground state in this vortex-type magnonic crystal is of interest both from fundamental and technological viewpoints. Control of vortex chirality has been demonstrated previously using various techniques; however, control and manipulation of vortex polarities remain challenging. In this work, we present a robust and efficient way of selecting the ground state configuration of interacting magnetic elements using resonant-spin-ordering approach. This is achieved by driving the system from the linear regime of constant vortex gyrations to the non-linear regime of vortex-core reversals at a fixed excitation frequency of one of the coupled modes. Subsequently reducing the excitation field to the linear regime stabilizes the system to a polarity combination whose resonant frequency is decoupled from the initialization frequency. We have utilized the resonant approach to transition between the two polarity combinations (parallel or antiparallel) in a model system of connected dot-pairs which may form the building blocks of vortex-based magnonic crystals. Taking a step further, we have extended the technique by studying many-particle system for its potential as spin-torque oscillators or logic devices. Work at Argonne was supported by the U. S. DOE, Office of BES, under Contract No. DE-AC02-06CH11357. This work was in part supported by grant DMR-1015175 from the U. S. National Science Foundation, by a Contract from the U.S. Army TARDEC and RDECOM.

  6. Nanostructures for Enhanced Light Absorption in Solar Energy Devices

    Directory of Open Access Journals (Sweden)

    Gustav Edman Jonsson

    2011-01-01

    Full Text Available The fascinating optical properties of nanostructured materials find important applications in a number of solar energy utilization schemes and devices. Nanotechnology provides methods for fabrication and use of structures and systems with size corresponding to the wavelength of visible light. This opens a wealth of possibilities to explore the new, often of resonance character, phenomena observed when the object size and the electromagnetic field periodicity (light wavelength λ match. Here we briefly review the effects and concepts of enhanced light absorption in nanostructures and illustrate them with specific examples from recent literature and from our studies. These include enhanced optical absorption of composite photocatalytically active TiO2/graphitic carbon films, systems with enhanced surface plasmon resonance, field-enhanced absorption in nanofabricated carbon structures with geometrical optical resonances and excitation of waveguiding modes in supported nanoparticle assembles. The case of Ag particles plasmon-mediated chemistry of NO on graphite surface is highlighted to illustrate the principle of plasmon-electron coupling in adsorbate systems.

  7. Broadband infrared absorption enhancement by electroless-deposited silver nanoparticles

    DEFF Research Database (Denmark)

    Gritti, Claudia; Raza, Søren; Kadkhodazadeh, Shima

    2017-01-01

    Decorating semiconductor surfaces with plasmonic nanoparticles (NPs) is considered a viable solution for enhancing the absorptive properties of photovoltaic and photodetecting devices. We propose to deposit silver NPs on top of a semiconductor wafer by a cheap and fast electroless plating technique....... Optical characterization confirms that the random array of electroless-deposited NPs improves absorption by up to 20% in a broadband of nearinfrared frequencies from the bandgap edge to 2000 nm. Due to the small filling fraction of particles, the reflection in the visible range is practically unchanged......, which points to the possible applications of such deposition method for harvesting photons in nanophotonics and photovoltaics. The broadband absorption is a consequence of the resonant behavior of particles with different shapes and sizes, which strongly localize the incident light at the interface...

  8. Terahertz gas sensor based on absorption-induced transparency

    Directory of Open Access Journals (Sweden)

    Rodrigo Sergio G.

    2016-01-01

    Full Text Available A system for the detection of spectral signatures of gases at the Terahertz regime is presented. The system consists in an initially opaque holey metal film whereby the introduction of a gas provokes the appearance of spectral features in transmission and reflection, due to the phenomenom of absorption-induced transparency (AIT. The peaks in transmission and dips in reflection observed in AIT occur close to the absorption energies of the molecules, hence its name. The presence of the gas would be thus revealed as a strong drop in reflectivity measurements at one (or several of the gas absorption resonances. As a proof of principle, we theoretically demonstrate how the AIT-based sensor would serve to detect tiny amounts of hydrocyanic acid.

  9. Note Taking for Geography Students.

    Science.gov (United States)

    Kneale, Pauline E.

    1998-01-01

    Addresses geography students' questions about why, when, and how to take notes. Outlines a step-by-step process for taking notes from written sources and from class lectures. Discusses what types of notes are appropriate for various types of sources. Suggests some ideas for making notes useful for individual learning styles. (DSK)

  10. Cyclotron resonance in a cathode ray tube

    International Nuclear Information System (INIS)

    Gherbanovschi, N.; Tanasa, M.; Stoican, O.

    2002-01-01

    Absorption of the RF energy by the electron beam in a cathode ray tube due to the cyclotron resonance is described. The cathode ray tube is placed within a Helmholtz coils system supplied by a sawtooth current generator. In order to generate RF field and to detect RF absorption a gate dip-meter equipped with a FET transistor is used. The bias voltage variations of the FET transistors as a function of the magnetic field are recorded. The operating point of the cathode ray tube has been chosen so that the relaxation oscillations of the detection system can be observed. (authors)

  11. Nonlinear Cyclotron absorption of a hole doppleron in cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Voloshin, I.F.; Bugal' ter, G.A.; Demikhovskii, V.Y.; Fisher, L.M.; Yudin, V.A.

    1977-10-01

    We investigated experimentally the nonlinear behavior of the impedance of a cadmium plate in the region of existence of the hole doppleron. It is shown theoretically that this phenomenon can be attributed to nonlinear cyclotron absorption of the wave in the metal. A theory of nonlinear cyclotron absorption of a hole doppleron in cadmium is constructed. The nonlinearity is due to the influence of the wave magnetic field H that alters the trajectories of the resonant electrons responsible for the cyclotron asorption. The Lorentz force connected with the field H modulates the particle velocity along the magnetic field at a characteristic frequency ..omega../sub 0/ proportional to the square root of the wave amplitude. The modulation of the longitudinal particle velocity leads to violation of the condition of their resonant interaction with the wave, as a result of which the absorption coefficient decreases. The nonlinearity is significant when the frequency ..omega../sub 0/ is large compared with the electron-collision frequency. A decrease of the cyclotron absorption changes radically the picture of the surface-impedance oscillations of the plate in the magnetic field. We studied in the experiment the influence of the temperature, of the angle of inclination of the magnetic field, and of the frequency on the nonlinear-effect threshold field that separates the regions of linear and nonlinear behavior of the sample impedance. The measurement results are in qualitative agreement with the conclusions of the theory.

  12. Laser heating of large noble gas clusters: from the resonant to the relativistic interaction regimes

    Energy Technology Data Exchange (ETDEWEB)

    Gumbrell, E T; Moore, A S; Clark, E L; Garbett, W J; Comley, A J; Edwards, R D; Eagleton, R E [Plasma Physics Division, AWE Aldermaston, Reading RG7 4PR (United Kingdom); Lazarus, J A; Nilson, P M; Robinson, J S; Hohenberger, M; Symes, D R; Smith, R A [Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom); Clarke, R J [Rutherford Appleton Laboratory, Chilton OX11 0QX (United Kingdom)], E-mail: edward.gumbrell@awe.co.uk, E-mail: r.a.smith@imperial.ac.uk

    2008-12-15

    Wide-ranging measurements of sub-picosecond laser interactions with large noble gas cluster targets have been conducted in order to help clarify the nature and extent of the underlying laser-plasma heating. Within the sub-relativistic vacuum irradiance range of 10{sup 16}-10{sup 17} W cm{sup -2}, we find that electron temperatures measured with continuum x-ray spectroscopy exhibit a pronounced multi-keV enhancement. Analysis indicates this behaviour to be consistent with collisional or collisionless resonant heating mechanisms. We also present the first measurements of laser-to-cluster energy deposition at relativistic vacuum irradiances, our data demonstrating absorption fractions of 90% or more. Optical probing was used to resolve the onset of a supersonic ionization front resulting from this very high absorption, and shows that despite significant pre-focus heating, the greatest plasma energy densities can be generated about the vacuum focus position. Electron energy spectra measurements confirm that laser-plasma super-heating occurs, and together with ion data establish that relativistic laser-plasma coupling in atomic clusters can take place without significant MeV particle beam production. In conjunction with optical self-emission data, the optical probing also indicates laser pre-pulse effects at peak vacuum irradiance of 5 x 10{sup 19} W cm{sup -2}. Laser absorption, plasma heating and energy transport data are supported throughout with analytical and numerical modelling.

  13. Wave energy absorption by ducks

    OpenAIRE

    Kurniawan, Adi

    2017-01-01

    We study the absorption of wave energy by a single and multiple cam-shaped bodies referred to as ducks. Numerical models are developed under the assumptions of linear theory. We consider wave absorption by a single duck as well as by two lines of ducks meeting at an angle.

  14. Wave energy absorption by ducks

    DEFF Research Database (Denmark)

    Kurniawan, Adi

    2018-01-01

    We study the absorption of wave energy by a single and multiple cam-shaped bodies referred to as ducks. Numerical models are developed under the assumptions of linear theory. We consider wave absorption by a single duck as well as by two lines of ducks meeting at an angle....

  15. Atomic absorption instrument functional description

    International Nuclear Information System (INIS)

    Bystroff, R.I.; Boyle, W.G. Jr.; Barton, G.W. Jr.

    1976-01-01

    This report describes a proposed system for automating atomic absorption analysis. The system consists of two atomic absorption instruments and an automatic sampler that can be attached to either instrument. A computer program controls the sampling and gathers data. The program then uses the data to perform bookkeeping, data processing, and report writing

  16. Sublinear absorption in OCS gas

    International Nuclear Information System (INIS)

    Bogani, F.; Querzoli, R.; Ernst, K.

    1988-01-01

    Sublinear absorption in OCS gas has been experimentally studied in detail by means of an optoacustic technique and transmission measurements. The best fit of the results is obtained by a phenomenological model, that considers the process as the sum of one-and two-photon absorptions

  17. Optical absorption of irradiated carbohydrates

    International Nuclear Information System (INIS)

    Supe, A.A.; Tiliks, Yu.E.

    1994-01-01

    The optical absorption spectra of γ-irradiated carbohydrates (glucose, lactose, sucrose, maltose, and starch) and their aqueous solutions were studied. The comparison of the data obtained with the determination of the concentrations of molecular and radical products of radiolysis allows the absorption bands with maxima at 250 and 310 nm to be assigned to the radicals trapped in the irradiated carbohydrates

  18. Water absorption in brick masonry

    NARCIS (Netherlands)

    Brocken, H.J.P.; Smolders, H.R.

    1996-01-01

    The water absorption in brick, mortar that was cured separately, and masonry samples was studied using NMR. Models of the moisture transport are usually formulated on the basis of a diffusion equation. In the case of water absorption in separate brick and mortar samples, the moisture diffusivity in

  19. Subgap absorption in conjugated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, M.; Seager, C.H. (Sandia National Labs., Albuquerque, NM (USA)); McBranch, D.; Heeger, A.J. (California Univ., Santa Barbara, CA (USA)); Baker, G.L. (Bell Communications Research, Inc., Red Bank, NJ (USA))

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of < 10{sup {minus}5}, Photothermal Deflection Spectroscopy (PDS) is ideal for determining the absorption coefficients of thin films of transparent'' materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination. 11 refs., 4 figs.

  20. Multifunctional hybrids for electromagnetic absorption

    International Nuclear Information System (INIS)

    Huynen, I.; Quievy, N.; Bailly, C.; Bollen, P.; Detrembleur, C.; Eggermont, S.; Molenberg, I.; Thomassin, J.M.; Urbanczyk, L.

    2011-01-01

    Highlights: → EM absorption requires low dielectric constant and ∼1 S/m electrical conductivity. → New hybrids were processed with CNT-filled polymer foam inserted in Al honeycomb. → The EM absorption in the GHz range is superior to any known material. → A closed form model is used to guide the design of the hybrid. → The architectured material is light with potential for thermal management. - Abstract: Electromagnetic (EM) interferences are ubiquitous in modern technologies and impact on the reliability of electronic devices and on living cells. Shielding by EM absorption, which is preferable over reflection in certain instances, requires combining a low dielectric constant with high electrical conductivity, which are antagonist properties in the world of materials. A novel class of hybrid materials for EM absorption in the gigahertz range has been developed based on a hierarchical architecture involving a metallic honeycomb filled with a carbon nanotube-reinforced polymer foam. The waveguide characteristics of the honeycomb combined with the performance of the foam lead to unexpectedly large EM power absorption over a wide frequency range, superior to any known material. The peak absorption frequency can be tuned by varying the shape of the honeycomb unit cell. A closed form model of the EM reflection and absorption provides a tool for the optimization of the hybrid. This designed material sets the stage for a new class of sandwich panels combining high EM absorption with mass efficiency, stiffness and thermal management.

  1. Taking Light For a Walk

    Indian Academy of Sciences (India)

    IAS Admin

    RESONANCE │ November 2013 ... tonic crystals and highlight the important mile- stones in ... greater the refractive index of the medium, slower is the ... monochromatic light wave as it travels through vacuum, .... zero (frozen light) or even negative (backward light). .... quency acoustic wave and vibrational excitation in the.

  2. Narrow dibaryon resonances

    International Nuclear Information System (INIS)

    Kajdalov, A.B.

    1986-01-01

    Experimental data on np interactions indicating to existence of narrow resonances in pp-system are discussed. Possible theoretical interpretations of these resonances are given. Experimental characteristics of the dibaryon resonances with isospin I=2 are considered

  3. MRI (Magnetic Resonance Imaging)

    Science.gov (United States)

    ... Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Magnetic Resonance Imaging (MRI) is a medical imaging procedure for ...

  4. Laser cooling at resonance

    Science.gov (United States)

    Yudkin, Yaakov; Khaykovich, Lev

    2018-05-01

    We show experimentally that three-dimensional laser cooling of lithium atoms on the D2 line is possible when the laser light is tuned exactly to resonance with the dominant atomic transition. Qualitatively, it can be understood by applying simple Doppler cooling arguments to the specific hyperfine structure of the excited state of lithium atoms, which is both dense and inverted. However, to build a quantitative theory, we must resolve to a full model which takes into account both the entire atomic structure of all 24 Zeeman sublevels and the laser light polarization. Moreover, by means of Monte Carlo simulations, we show that coherent processes play an important role in showing consistency between the theory and the experimental results.

  5. Effects of Ag Nanocubes with Different Corner Shape on the Absorption Enhancement in Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Feng Shan

    2014-01-01

    Full Text Available The effects of corner shape of silver (Ag nanocubes (NCs on optical absorptions of organic solar cells (OSCs are theoretically investigated by finite element method (FEM calculations. The absorption of sun light in the active layer is calculated. Significant absorption enhancements have been demonstrated in metallic region with different shapes of Ag NCs, among them corner radius (R is zero result in the best light absorption performance of up to 55% enhancement with respect to bare OSCs. The origins of increased absorption are believed to be the effects of the huge electric field enhancement and increased scattering upon the excitation of localized surface plasmon resonance (LSPR. Apart from using R=0, we show that R=3, 6, and 11.29 of Ag NCs in metallic region of active layer may also result in the maximum comparable absorption enhancement of 49%, 41%, and 28%, respectively. In addition, a significant effect of the period of NCs is observed.

  6. Thermionic detection of the ionic fragments of continiuum-state pair absorption systems

    International Nuclear Information System (INIS)

    Hotop, R.; Niemax, K.; Richter, J.; Weber, K.H.

    1981-01-01

    Using a thermionic diode we have detected the ionic fragments formed by associative ionization and dissociation after continuum-state pair absorption processes in Cs-Cs and Cs-K systems. Assuming an ionization probability of unity of the excited species and calibrating the pair absorption bands by taking into account the known photoionization cross section of the atoms we found excellent agreement with data from classical absorption measurements. (orig.)

  7. Take Charge. Take the Test. "You Know" PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    2012-03-07

    As part of the Take Charge. Take the Test. campaign, this 60 second PSA encourages African American women to get tested for HIV. Locations for a free HIV test can be found by visiting hivtest.org/takecharge or calling 1-800-CDC-INFO (1-800-232-4636).  Created: 3/7/2012 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 3/7/2012.

  8. Regenerative feedback resonant circuit

    Science.gov (United States)

    Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.

    2014-09-02

    A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.

  9. Influence of resonance parameters' correlations on the resonance integral uncertainty; 55Mn case

    International Nuclear Information System (INIS)

    Zerovnik, Gasper; Trkov, Andrej; Capote, Roberto; Rochman, Dimitri

    2011-01-01

    For nuclides with a large number of resonances the covariance matrix of resonance parameters can become very large and expensive to process in terms of the computation time. By converting covariance matrix of resonance parameters into covariance matrices of background cross-section in a more or less coarse group structure a considerable amount of computer time and memory can be saved. The question is how important is the information that is discarded in the process. First, the uncertainty of the 55 Mn resonance integral was estimated in narrow resonance approximation for different levels of self-shielding using Bondarenko method by random sampling of resonance parameters according to their covariance matrices from two different 55 Mn evaluations: one from Nuclear Research and Consultancy Group NRG (with large uncertainties but no correlations between resonances), the other from Oak Ridge National Laboratory (with smaller uncertainties but full covariance matrix). We have found out that if all (or at least significant part of the) resonance parameters are correlated, the resonance integral uncertainty greatly depends on the level of self-shielding. Second, it was shown that the commonly used 640-group SAND-II representation cannot describe the increase of the resonance integral uncertainty. A much finer energy mesh for the background covariance matrix would have to be used to take the resonance structure into account explicitly, but then the objective of a more compact data representation is lost.

  10. Broadband Reflectionless Metasheets: Frequency-Selective Transmission and Perfect Absorption

    Directory of Open Access Journals (Sweden)

    V. S. Asadchy

    2015-07-01

    Full Text Available Energy of propagating electromagnetic waves can be fully absorbed in a thin lossy layer, but only in a narrow frequency band, as follows from the causality principle. On the other hand, it appears that there are no fundamental limitations on broadband matching of thin resonant absorbing layers. However, known thin absorbers produce significant reflections outside of the resonant absorption band. In this paper, we explore possibilities to realize a thin absorbing layer that produces no reflected waves in a very wide frequency range, while the transmission coefficient has a narrow peak of full absorption. Here we show, both theoretically and experimentally, that a thin resonant absorber, invisible in reflection in a very wide frequency range, can be realized if one and the same resonant mode of the absorbing array unit cells is utilized to create both electric and magnetic responses. We test this concept using chiral particles in each unit cell, arranged in a periodic planar racemic array, utilizing chirality coupling in each unit cell but compensating the field coupling at the macroscopic level. We prove that the concept and the proposed realization approach also can be used to create nonreflecting layers for full control of transmitted fields. Our results can have a broad range of potential applications over the entire electromagnetic spectrum including, for example, perfect ultracompact wave filters and selective multifrequency sensors.

  11. Resonances, resonance functions and spectral deformations

    International Nuclear Information System (INIS)

    Balslev, E.

    1984-01-01

    The present paper is aimed at an analysis of resonances and resonance states from a mathematical point of view. Resonances are characterized as singular points of the analytically continued Lippman-Schwinger equation, as complex eigenvalues of the Hamiltonian with a purely outgoing, exponentially growing eigenfunction, and as poles of the S-matrix. (orig./HSI)

  12. Resonant interaction of photons with gravitational waves

    International Nuclear Information System (INIS)

    Mendonca, J.T.; Drury, L. O'C.

    2002-01-01

    The interaction of photons with a low-amplitude gravitational wave propagating in a flat space-time is studied by using an exact model of photon dynamics. The existence of nearly resonant interactions between the photons and the gravitational waves, which can take place over large distances, can lead to a strong photon acceleration. Such a resonant mechanism can eventually be useful to build consistent new models of gamma-ray emitters

  13. Optical performance and metallic absorption in nanoplasmonic systems.

    Science.gov (United States)

    Arnold, Matthew D; Blaber, Martin G

    2009-03-02

    Optical metrics relating to metallic absorption in representative plasmonic systems are surveyed, with a view to developing heuristics for optimizing performance over a range of applications. We use the real part of the permittivity as the independent variable; consider strengths of particle resonances, resolving power of planar lenses, and guiding lengths of planar waveguides; and compare nearly-free-electron metals including Al, Cu, Ag, Au, Li, Na, and K. Whilst the imaginary part of metal permittivity has a strong damping effect, field distribution is equally important and thus factors including geometry, real permittivity and frequency must be considered when selecting a metal. Al performs well at low permittivities (e.g. sphere resonances, superlenses) whereas Au & Ag only perform well at very negative permittivities (shell and rod resonances, LRSPP). The alkali metals perform well overall but present engineering challenges.

  14. The influence of adsorption capacity on enhanced gas absorption in activated carbon slurries

    NARCIS (Netherlands)

    Holstvoogd, R.D.; van Swaaij, Willibrordus Petrus Maria

    1990-01-01

    The enhanced absorption of gases in aqueous activated carbbon slurries of fine particles is studied with a non-steady-state absorption model, taking into account the finite adsorption capacity of the carbon particles. It has been found that, for the different gas/activated carbon slurry systems

  15. Dye Giant Absorption and Light Confinement Effects in Porous Bragg Microcavities

    DEFF Research Database (Denmark)

    Oliva-Ramírez, Manuel; Gil-Rostra, Jorge; Simonsen, Adam C.

    2018-01-01

    This work presents a simple experimental procedure to probe light confinement effects in photonic structures. Two types of porous 1D Bragg microcavities with two resonant peaks in the reflection gap were prepared by physical vapor deposition at oblique angle configurations and then infiltrated...... with dye solutions of increasing concentrations. The unusual position shift and intensity drop of the transmitted resonant peak observed when it was scanned through the dye absorption band have been accounted for by the effect of the light trapped at their optical defect layer. An experimentally observed...... giant absorption of the dye molecules and a strong anomalous dispersion in the refractive index of the solution are claimed as the reasons for the observed variations in the Bragg microcavity resonant feature. Determining the giant absorption of infiltrated dye solutions is proposed as a general...

  16. Economic inequality increases risk taking.

    Science.gov (United States)

    Payne, B Keith; Brown-Iannuzzi, Jazmin L; Hannay, Jason W

    2017-05-02

    Rising income inequality is a global trend. Increased income inequality has been associated with higher rates of crime, greater consumer debt, and poorer health outcomes. The mechanisms linking inequality to poor outcomes among individuals are poorly understood. This research tested a behavioral account linking inequality to individual decision making. In three experiments ( n = 811), we found that higher inequality in the outcomes of an economic game led participants to take greater risks to try to achieve higher outcomes. This effect of unequal distributions on risk taking was driven by upward social comparisons. Next, we estimated economic risk taking in daily life using large-scale data from internet searches. Risk taking was higher in states with greater income inequality, an effect driven by inequality at the upper end of the income distribution. Results suggest that inequality may promote poor outcomes, in part, by increasing risky behavior.

  17. Should You Take Dietary Supplements?

    Science.gov (United States)

    ... 2013 Print this issue Should You Take Dietary Supplements? A Look at Vitamins, Minerals, Botanicals and More ... Gut in Check Wise Choices Safe Use of Supplements Tell all of your health care providers about ...

  18. Conceptualizing Multicultural Perspective Taking Skills

    National Research Council Canada - National Science Library

    Rentsch, Joan R; Gunderson, Allison; Goodwin, Gerald F; Abbe, Allison

    2007-01-01

    .... The ability to take the perspective of individuals within the context of their culture enables Army leaders to understand other cultures at a level finer than that afforded by simply using global...

  19. Subgap Absorption in Conjugated Polymers

    Science.gov (United States)

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination.

  20. Photon scattering by the giant dipole resonance

    International Nuclear Information System (INIS)

    Bowles, T.J.; Holt, R.J.; Jackson, H.E.; McKeown, R.D.; Specht, J.R.

    1979-01-01

    Although many features of the giant dipole resonance are well known, the coupling between the basic dipole oscillation and other nuclear collective degrees of freedom such as surface vibrations and rotations is poorly understood. This aspect was investigated by elastic and inelastic bremsstrahlung scattering of tagged photons over the energy range 15 to 22 MeV. Target nuclei were 60 Ni, 52 Cr, 56 Fe, 92 Mo, and 96 Mo. Scattering and absorption cross sections are tabulated, along with parameters obtained from a two-Lorentzian analysis of the scattering cross sections; measured spectra are shown. It was necessary to remove Thomson scattering from the experimental results. It was found that coupling to surface vibrations in the giant dipole resonance is much weaker than the dynamic collective model suggests. The elastic scattering cross section for all targets but 60 Ni showed structure that is not evident in the absorption cross section measurement. 12 figures, 2 tables

  1. The effect of self-absorption in hollow cathode lamp on its temperature

    International Nuclear Information System (INIS)

    Sobhanian, S.; Naghshara, H.

    2014-01-01

    It has been shown experimentally that even a small error in the calculation of the temperature inside the hollow-cathode lamp (HCL) and the current applied to the lamp, may cause a tremendous error in determination of the absorption ratio in optical resonance absorption (ORA) method. This effect is intensified nonlinearity for large absorption ratios. If a higher current is applied to a copper hollow cathode lamp, the copper density inside the lamp is increasing rapidly. Due to the cylindrical (axisymmetric) form of the lamp, the density of atoms around the main axis of the lamp becomes greater than that near the internal wall. In this case the auto-absorption (or self-absorption) is occurred and as its result, the emission spectrum produced by copper atoms is locally absorbed before going out from the lamp. This absorption is stronger near the main axis compared with the areas near the wall because of the Gaussian profile of the spectral line. Two different Cu atoms ground state lines with the similar lower state (327.4 nm and 324.7 nm) are used in this work as optical resonance absorption and the absorption coefficient is obtained for three different pressures (0.6, 4.5 and 14 µbar). The best values for copper HCL temperature and for maximum HCL current were found respectively 450 K, and 5mA. (author)

  2. Sabine absorption coefficients to random incidence absorption coefficients

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2014-01-01

    into random incidence absorption coefficients for porous absorbers are investigated. Two optimization-based conversion methods are suggested: the surface impedance estimation for locally reacting absorbers and the flow resistivity estimation for extendedly reacting absorbers. The suggested conversion methods...

  3. Highly selective population of two excited states in nonresonant two-photon absorption

    International Nuclear Information System (INIS)

    Zhang Hui; Zhang Shi-An; Sun Zhen-Rong

    2011-01-01

    A nonresonant two-photon absorption process can be manipulated by tailoring the ultra-short laser pulse. In this paper, we theoretically demonstrate a highly selective population of two excited states in the nonresonant two-photon absorption process by rationally designing a spectral phase distribution. Our results show that one excited state is maximally populated while the other state population is widely tunable from zero to the maximum value. We believe that the theoretical results may play an important role in the selective population of a more complex nonlinear process comprising nonresonant two-photon absorption, such as resonance-mediated (2+1)-three-photon absorption and (2+1)-resonant multiphoton ionization. (atomic and molecular physics)

  4. Optoacoustic measurements of water vapor absorption at selected CO laser wavelengths in the 5-micron region

    Science.gov (United States)

    Menzies, R. T.; Shumate, M. S.

    1976-01-01

    Measurements of water vapor absorption were taken with a resonant optoacoustical detector (cylindrical pyrex detector, two BaF2 windows fitted into end plates at slight tilt to suppress Fabry-Perot resonances), for lack of confidence in existing spectral tabular data for the 5-7 micron region, as line shapes in the wing regions of water vapor lines are difficult to characterize. The measurements are required for air pollution studies using a CO laser, to find the differential absorption at the wavelengths in question due to atmospheric constituents other than water vapor. The design and performance of the optoacoustical detector are presented. Effects of absorption by ambient NO are considered, and the fixed-frequency discretely tunable CO laser is found suitable for monitoring urban NO concentrations in a fairly dry climate, using the water vapor absorption data obtained in the study.

  5. Tunable ultranarrow spectrum selective absorption in a graphene monolayer at terahertz frequency

    Science.gov (United States)

    Wu, Jun

    2016-06-01

    Complete absorption in a graphene monolayer at terahertz frequency through the critical coupling effect is investigated. It is achieved by sandwiching the graphene monolayer between a dielectric grating and a Bragg grating. The designed graphene absorber exhibits near-unity absorption at resonance but with an ultranarrow spectrum and antenna-like response, which is attributed to the combined effects of guided mode resonance with dielectric grating and the photonic band gap with Bragg grating. In addition to numerical simulation, the electric field distributions are also illustrated to provide a physical understanding of the perfect absorption effect. Furthermore, the absorption performance can be tuned by only changing the Fermi level of graphene, which is beneficial for real application. It is believed that this study may be useful for designing next-generation graphene-based optoelectronic devices.

  6. Polariton condensation, superradiance and difference combination parametric resonance in mode-locked laser

    Science.gov (United States)

    Bagayev, S. N.; Arkhipov, R. M.; Arkhipov, M. V.; Egorov, V. S.; Chekhonin, I. A.; Chekhonin, M. A.

    2017-11-01

    The generation of the ring mode-locked laser containing resonant absorption medium in the cavity was investigated. It is shown that near the strong resonant absorption lines a condensation of polaritons arises. Intensive radiation looks like as superradiance in a medium without population inversion. We studied theoretically the microscopic mechanism of these phenomena. It was shown that in this system in absorbing medium a strong self-induced difference combination parametric resonance exists. Superradiance on polaritonic modes in the absorbing medium are due to the emergence of light-induced resonant polarization as a result of fast periodic nonadiabatic quantum jumps in the absorber.

  7. Absorption factor for cylindrical samples

    International Nuclear Information System (INIS)

    Sears, V.F.

    1984-01-01

    The absorption factor for the scattering of X-rays or neutrons in cylindrical samples is calculated by numerical integration for the case in which the absorption coefficients of the incident and scattered beams are not equal. An extensive table of values having an absolute accuracy of 10 -4 is given in a companion report [Sears (1983). Atomic Energy of Canada Limited, Report No. AECL-8176]. In the present paper an asymptotic expression is derived for the absorption factor which can be used with an error of less than 10 -3 for most cases of interest in both neutron inelastic scattering and neutron diffraction in crystals. (Auth.)

  8. Significantly improving nuclear resonance fluorescence non-destructive assay by using the integral resonance transmission method and photofission

    International Nuclear Information System (INIS)

    Angell, Christopher T.; Hayakawa, Takehito; Shizuma, Toshiyuki; Hajima, Ryoichi

    2013-01-01

    Non-destructive assay (NDA) of 239 Pu in spent nuclear fuel or melted fuel using a γ-ray beam is possible using self absorption and the integral resonance transmission method. The method uses nuclear resonance absorption where resonances in 239 Pu remove photons from the beam, and the selective absorption is detected by measuring the decrease in scattering in a witness target placed in the beam after the fuel, consisting of the isotope of interest, namely 239 Pu. The method is isotope specific, and can use photofission or scattered γ-rays to assay the 239 Pu. It overcomes several problems related to NDA of melted fuel, including the radioactivity of the fuel, and the unknown composition and geometry. This talk will explain the general method, and how photofission can be used to assay specific isotopes, and present example calculations. (author)

  9. Influence of the particle size dispersion on gamma-raidation absorption

    International Nuclear Information System (INIS)

    Bonchev, Ts.; Amin, S.S.

    1985-01-01

    The dependence of the value of the Moessbauer absorption on the patricle size of the absorbing material was investigated. It was assumed that: a) the investigated substance is with homogenious composition and that it consists of spherical particles; b) the particles are considered to be uniformly distributed in a matter practically negligible mass-absorption coefficient. The experiment was performed by using X-rays of Ni and Cu generated by the 14,4125 KeV resonance radiation of 57 Co

  10. Numerical analysis on the absorption, reflection and transmission of radar waves by a uniform magnetized plasma slab

    International Nuclear Information System (INIS)

    Tang Deli; Sun Aiping; Qiu Xiaoming

    2002-01-01

    The absorption, reflection, and transmission of radar waves by a uniform and magnetized plasma slab are studied. The effect of various plasma parameters and different values of magnetic field intensity on the absorbed, reflected and transmitted power are discussed. The calculated results show that the effects of magnetic field on the absorbed power as well as the frequency band of resonant absorption are very significant. More than 90% of radar wave power can be absorbed and the resonant absorption band is about 2G Hz

  11. Restrictions in the realisation of multipass unstable resonators

    International Nuclear Information System (INIS)

    Strakhov, S Yu

    2009-01-01

    Main restrictions in the realisation of multipass unstable resonators caused by intracavity losses and large-scale aberrations are considered. The influence of intracavity losses on the laser radiation power and divergence is analysed based on the numerical simulation of an unstable resonator. The efficiency criterion for the unstable multipass resonator is proposed, which is proportional to the radiation brightness and takes into account the influence of the misalignment, thermal deformation and the main parameters of the active medium and resonator on the parameters of laser radiation. (resonators)

  12. Approaching total absorption at near infrared in a large area monolayer graphene by critical coupling

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yonghao; Chadha, Arvinder; Zhao, Deyin; Shuai, Yichen; Menon, Laxmy; Yang, Hongjun; Zhou, Weidong, E-mail: wzhou@uta.edu [Nanophotonics Lab, Department of Electrical Engineering, University of Texas at Arlington, Arlington, Texas 76019 (United States); Piper, Jessica R.; Fan, Shanhui [Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Jia, Yichen; Xia, Fengnian [Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520 (United States); Ma, Zhenqiang [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2014-11-03

    We demonstrate experimentally close to total absorption in monolayer graphene based on critical coupling with guided resonances in transfer printed photonic crystal Fano resonance filters at near infrared. Measured peak absorptions of 35% and 85% were obtained from cavity coupled monolayer graphene for the structures without and with back reflectors, respectively. These measured values agree very well with the theoretical values predicted with the coupled mode theory based critical coupling design. Such strong light-matter interactions can lead to extremely compact and high performance photonic devices based on large area monolayer graphene and other two–dimensional materials.

  13. Extraordinary absorption of sound in porous lamella-crystals

    DEFF Research Database (Denmark)

    Christensen, Johan; Romero-García, V.; Picó, R.

    2014-01-01

    . Experimental measurements show that strong all-angle sound absorption with almost zero reflectance takes place for a frequency range exceeding two octaves. We demonstrate that lowering the crystal filling fraction increases the wave interaction time and is responsible for the enhancement of intrinsic material......We present the design of a structured material supporting complete absorption of sound with a broadband response and functional for any direction of incident radiation. The structure which is fabricated out of porous lamellas is arranged into a low-density crystal and backed by a reflecting support...

  14. Surface plasmon enhanced absorption and suppressed transmission in periodic arrays of graphene ribbons

    Science.gov (United States)

    Nikitin, A. Yu.; Guinea, F.; Garcia-Vidal, F. J.; Martin-Moreno, L.

    2012-02-01

    Resonance diffraction in the periodic array of graphene microribbons is theoretically studied following a recent experiment [L. Ju , Nature Nanotech.1748-338710.1038/nnano.2011.146 6, 630 (2011)]. Systematic studies over a wide range of parameters are presented. It is shown that a much richer resonant picture would be observable for higher relaxation times of charge carriers: More resonances appear and transmission can be totally suppressed. The comparison with the absorption cross-section of a single ribbon shows that the resonant features of the periodic array are associated with leaky plasmonic modes. The longest-wavelength resonance provides the highest visibility of the transmission dip and has the strongest spectral shift and broadening with respect to the single-ribbon resonance, due to collective effects.

  15. A SURVEY OF ALKALI LINE ABSORPTION IN EXOPLANETARY ATMOSPHERES

    International Nuclear Information System (INIS)

    Jensen, Adam G.; Redfield, Seth; Endl, Michael; Cochran, William D.; Koesterke, Lars; Barman, Travis S.

    2011-01-01

    We obtained over 90 hr of spectroscopic observations of four exoplanetary systems with the Hobby-Eberly Telescope. Observations were taken in transit and out of transit, and we analyzed the differenced spectra—i.e., the transmission spectra—to inspect it for absorption at the wavelengths of the neutral sodium (Na I) doublet at λλ5889, 5895 and neutral potassium (K I) at λ7698. We used the transmission spectrum at Ca I λ6122—which shows strong stellar absorption but is not an alkali metal resonance line that we expect to show significant absorption in these atmospheres—as a control line to examine our measurements for systematic errors. We use an empirical Monte Carlo method to quantify these systematic errors. In a reanalysis of the same data set using a reduction and analysis pipeline that was derived independently, we confirm the previously seen Na I absorption in HD 189733b at a level of (– 5.26 ± 1.69) × 10 –4 (the average value over a 12 Å integration band to be consistent with previous authors). Additionally, we tentatively confirm the Na I absorption seen in HD 209458b (independently by multiple authors) at a level of (– 2.63 ± 0.81) × 10 –4 , though the interpretation is less clear. Furthermore, we find Na I absorption of (– 3.16 ± 2.06) × 10 –4 at <3σ in HD 149026b; features apparent in the transmission spectrum are consistent with real absorption and indicate this may be a good target for future observations to confirm. No other results (Na I in HD 147506b and Ca I and K I in all four targets) are significant to ≥3σ, although we observe some features that we argue are primarily artifacts.

  16. Theory of strong-field attosecond transient absorption

    International Nuclear Information System (INIS)

    Wu, Mengxi; Chen, Shaohao; Camp, Seth; Schafer, Kenneth J; Gaarde, Mette B

    2016-01-01

    Attosecond transient absorption is one of the promising new techniques being developed to exploit the availability of sub-femtosecond extreme ultraviolet (XUV) pulses to study the dynamics of the electron on its natural time scale. The temporal resolution in a transient absorption setup comes from the control of the relative delay and coherence between pump and probe pulses, while the spectral resolution comes from the characteristic width of the features that are being probed. In this review we focus on transient absorption scenarios where an attosecond pulse of XUV radiation creates a broadband excitation that is subsequently probed by a few cycle infrared (IR) laser. Because the attosecond XUV pulses are locked to the IR field cycle, the exchange of energy in the laser–matter interaction can be studied with unprecedented precision. We focus on the transient absorption by helium atoms of XUV radiation around the first ionization threshold, where we can simultaneoulsy solve the time-dependent Schrödinger equation for the single atom response and the Maxwell wave equation for the collective response of the nonlinear medium. We use a time-domain method that allows us to treat on an equal footing all the different linear and nonlinear processes by which the medium can exchange energy with the fields. We present several simple models, based on a few-level system interacting with a strong IR field, to explain many of the novel features found in attosecond transient absorption spectrograms. These include the presence of light-induced states, which demonstrate the ability to probe the dressed states of the atom. We also present a time-domain interpretation of the resonant pulse propagation features that appear in absorption spectra in dense, macroscopic media. We close by reviewing several recent experimental results that can be explained in terms of the models we discuss. Our aim is to present a road map for understanding future attosecond transient absorption

  17. OZONE ABSORPTION IN RAW WATERS

    Directory of Open Access Journals (Sweden)

    LJILJANA TAKIĆ

    2008-03-01

    Full Text Available The ozone absorption in raw water entering the main ozonization step at the Belgrade drinking water supply plant was investigated in a continuous stirred tank reactor (CSTR. A slow chemical reaction rate of dissolved ozone and pollutants present in raw water have been experimentally determined. The modified Hatta number was defined and calculated as a criterion which determines whether and to which extent the reactions of ozone and pollutants influence the rate of the pure physical ozone absorption.

  18. Microwaves absorption in superconducting materials

    International Nuclear Information System (INIS)

    Biasi, R.S. de; Fernandes, A.A.R.; Pereira, R.F.R.

    1989-01-01

    Microwaves absorption measures in two superconductors ceramics systems, Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O are compared with similars datas obtained in the same band of temperature by a conventional method, mutual inductance. The results suggest that the microwaves absorption can be used as single and non-destructive method for investigating the properties of ceramics superconductors. (C.G.C.) [pt

  19. Evidence of a Nonequilibrium Distribution of Quasiparticles in the Microwave Response of a Superconducting Aluminum Resonator

    NARCIS (Netherlands)

    De Visser, P.J.; Goldie, D.J.; Diener, P.; Withington, S.; Baselmans, J.J.A.; Klapwijk, T.M.

    2014-01-01

    In a superconductor, absorption of photons with an energy below the superconducting gap leads to redistribution of quasiparticles over energy and thus induces a strong nonequilibrium quasiparticle energy distribution. We have measured the electrodynamic response, quality factor, and resonant

  20. Resonance broadening in an intense light field

    International Nuclear Information System (INIS)

    Andreev, S.P.; Lisitsa, V.S.

    1977-01-01

    Collisions of identical atoms in a strong resonance radiation field E 0 cosωt, for which the atomic oscillation period is comparable to the collision time of the atoms, are considered. The problem is treated in terms of the simplest two-level atomic model. The problem of light absorption in such collisions is reduced to the problem of inelastic transitions in a three-level compound system of two atoms and an electromagnetic field. Corresponding probabilities and inelastic scattering integral cross sections for transitions between energy levels in such a system are calculated for two extreme cases- the impact (rapid collisions) and the static one (slow collisions). In the general case the cross sections depend nonlinearly on Esub(0). For small Esub(0) as compared to a certain critical Esub(0)* the results are similar to those of the well-known linear theory of resonance broadening. For Esub(0)>>Esub(0)* the absorption in the line wing is found to decrease (with increase of Esub(0)-the medium becomes more ''transparent''). The kinetics of light absorption in the medium of identical atoms with constant absorption capacity is analysed