International Nuclear Information System (INIS)
A microwave polarimetric scattering model for a forest canopy is developed based on the iterative solution of the vector radiative transfer equations up to the second order. The forest canopy constituents (branches, leaves, stems, and trunks) are embedded in a multi-layered medium over a rough interface. The branches, stems, and trunks are modeled as finite randomly oriented cylinders. Deciduous leaves are modeled as randomly oriented discs and coniferous leaves are modeled as randomly oriented needles. The vector radiative transfer equations contain non-diagonal extinction matrices that account for the difference in propagation constants and the attenuation rates between the vertical and horizontal polarizations. For a plane wave exciting the canopy, the average Mueller matrix is formulated, and then used to determine the linearly polarized backscattering coefficients including both the copolarized and cross-polarized power returns. Comparisons of the model with measurements from Les Landes Forest of France showed good agreements over a wide frequency band and gave a quantitative understanding of the relation between the backscattering coefficients and the age of the trees in the forest and forest biomass. (author)
Light scattering reviews 8 radiative transfer and light scattering
Kokhanovsky, Alexander A
2013-01-01
Light scattering review (vol 8) is aimed at the presentation of recent advances in radiative transfer and light scattering optics. The topics to be covered include: scattering of light by irregularly shaped particles suspended in atmosphere (dust, ice crystals), light scattering by particles much larger as compared the wavelength of incident radiation, atmospheric radiative forcing, astrophysical radiative transfer, radiative transfer and optical imaging in biological media, radiative transfer of polarized light, numerical aspects of radiative transfer.
Polarization Transfer in Proton Compton Scattering at High Momentum Transfer
International Nuclear Information System (INIS)
Compton scattering from the proton was investigated at s=6.9 GeV2 and t=-4.0 GeV2 via polarization transfer from circularly polarized incident photons. The longitudinal and transverse components of the recoil proton polarization were measured. The results are in disagreement with a prediction of perturbative QCD based on a two-gluon exchange mechanism, but agree well with a prediction based on a reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton
Polarization Transfer in Proton Compton Scattering at High Momentum Transfer
Hamilton, D J; Aniol, K A; Annand, J R M; Bertin, P Y; Bimbot, L; Bosted, P; Calarco, J R; Camsonne, A; Chang, G C; Chang, T H; Chen, J P; Seonho Choi; Chudakov, E; Danagulyan, A S; Degtyarenko, P; De Jager, C W; Deur, A; Dutta, D; Egiyan, K; Gao, H; Garibaldi, F; Gayou, O; Gilman, R; Glamazdin, A; Glashausser, C; Gómez, J; Hansen, J O; Hayes, D; Higinbotham, D W; Hinton, W; Horn, T; Howell, C; Hunyady, T; Hyde-Wright, C E; Jiang, X; Jones, M K; Khandaker, M; Ketikyan, A; Koubarovski, V; Krämer, K; Kumbartzki, G; Laveissière, G; Le Rose, J J; Lindgren, R A; Margaziotis, D J; Markowitz, P; McCormick, K; Meziani, Z E; Michaels, R; Moussiegt, P; Nanda, S; Nathan, A M; Nikolenko, D M; Nelyubin, V V; Norum, B E; Paschke, K; Pentchev, L; Perdrisat, C F; Piasetzky, E; Pomatsalyuk, R I; Punjabi, V A; Rachek, Igor A; Radyushkin, A V; Reitz, B; Roché, R; Roedelbronn, M; Ron, G; Sabatie, F; Saha, A; Savvinov, N; Shahinyan, A; Shestakov, Yu V; Sirca, S; Slifer, K J; Solvignon, P; Stoler, P; Tajima, S; Sulkosky, V; Todor, L; Vlahovic, B; Weinstein, L B; Wang, K; Wojtsekhowski, B; Voskanyan, H; Xiang, H; Zheng, X; Zhu, L
2004-01-01
Compton scattering from the proton was investigated at s=6.9 (GeV/c)**2 and \\t=-4.0 (GeV/c)**2 via polarization transfer from circularly polarized incident photons. The longitudinal and transverse components of the recoil proton polarization were measured. The results are in excellent agreement with a prediction based on a reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton and in disagreement with a prediction of pQCD based on a two-gluon exchange mechanism.
Energy Transfer in Scattering by Rotating Potentials
Indian Academy of Sciences (India)
Volker Enss; Vadim Kostrykin; Robert Schrader
2002-02-01
Quantum mechanical scattering theory is studied for time-dependent Schrödinger operators, in particular for particles in a rotating potential. Under various assumptions about the decay rate at infinity we show uniform boundedness in time for the kinetic energy of scattering states, existence and completeness of wave operators, and existence of a conserved quantity under scattering. In a simple model we determine the energy transferred to a particle by collision with a rotating blade.
Energy Technology Data Exchange (ETDEWEB)
Zhuo, Ye
2011-05-15
In this thesis, we theoretically study the electromagnetic wave propagation in several passive and active optical components and devices including 2-D photonic crystals, straight and curved waveguides, organic light emitting diodes (OLEDs), and etc. Several optical designs are also presented like organic photovoltaic (OPV) cells and solar concentrators. The first part of the thesis focuses on theoretical investigation. First, the plane-wave-based transfer (scattering) matrix method (TMM) is briefly described with a short review of photonic crystals and other numerical methods to study them (Chapter 1 and 2). Next TMM, the numerical method itself is investigated in details and developed in advance to deal with more complex optical systems. In chapter 3, TMM is extended in curvilinear coordinates to study curved nanoribbon waveguides. The problem of a curved structure is transformed into an equivalent one of a straight structure with spatially dependent tensors of dielectric constant and magnetic permeability. In chapter 4, a new set of localized basis orbitals are introduced to locally represent electromagnetic field in photonic crystals as alternative to planewave basis. The second part of the thesis focuses on the design of optical devices. First, two examples of TMM applications are given. The first example is the design of metal grating structures as replacements of ITO to enhance the optical absorption in OPV cells (chapter 6). The second one is the design of the same structure as above to enhance the light extraction of OLEDs (chapter 7). Next, two design examples by ray tracing method are given, including applying a microlens array to enhance the light extraction of OLEDs (chapter 5) and an all-angle wide-wavelength design of solar concentrator (chapter 8). In summary, this dissertation has extended TMM which makes it capable of treating complex optical systems. Several optical designs by TMM and ray tracing method are also given as a full complement of this
Elastic scattering and quasi-elastic transfers
International Nuclear Information System (INIS)
Experiments are presented which it will be possible to carry out at GANIL on the elastic scattering of heavy ions: diffraction phenomena if the absorption is great, refraction phenomena if absorption is low. The determination of the optical parameters can be performed. The study of the quasi-elastic transfer reactions will make it possible to know the dynamics of the nuclear reactions, form exotic nuclei and study their energy excitation spectrum, and analyse the scattering and reaction cross sections
Polarisation Transfer in Proton Compton Scattering at High Momentum Transfer
Energy Technology Data Exchange (ETDEWEB)
Hamilton, David
2004-12-31
The Jefferson Lab Hall A experiment E99-114 comprised a series of measurements to explore proton Compton scattering at high momentum transfer. For the first time, the polarisation transfer observables in the p (~ 0 ~ p) reaction were measured in the GeV energy range, where it is believed that quark-gluon degrees of freedom begin to dominate. The experiment utilised a circularly polarised photon beam incident on a liquid hydrogen target, with the scattered photon and recoil proton detected in a lead-glass calorimeter and a magnetic spectrometer, respectively.
Computation of scattering kernels in radiative transfer
International Nuclear Information System (INIS)
This note proposes rapidly convergent computational formulae for evaluating scattering kernels from radiative transfer theory. The approach used here does not rely on Legendre expansions, but rather uses exponentially convergent numerical integration rules. The relation between the domain of analyticity of a given phase function and the speed of convergence is studied in detail. - Highlights: • We propose the trapezoidal rule for the computation of scattering kernels. • The convergence rate is related to the analyticity of the phase function. • This provides a unified rapidly convergent computational approach
Energy Technology Data Exchange (ETDEWEB)
Engelhart, Daniel P.; Grätz, Fabian; Wagner, Roman J. V.; Wodtke, Alec M.; Schäfer, Tim, E-mail: tschaef4@gwdg.de [Institute for Physical Chemistry, Georg-August University of Göttingen, Tammannstraße 6, 37077 Göttingen (Germany); Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077 Göttingen (Germany); Haak, Henrik [Fritz Haber Insitute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin (Germany); Meijer, Gerard [Radboud University, 6500 HC Nijmegen (Netherlands)
2015-04-15
We report on the design and characterization of a new apparatus for performing quantum-state resolved surface scattering experiments. The apparatus combines optical state-specific molecule preparation with a compact hexapole and a Stark decelerator to prepare carrier gas-free pulses of quantum-state pure CO molecules with velocities controllable between 33 and 1000 m/s with extremely narrow velocity distributions. The ultrahigh vacuum surface scattering chamber includes homebuilt ion and electron detectors, a closed-cycle helium cooled single crystal sample mount capable of tuning surface temperature between 19 and 1337 K, a Kelvin probe for non-destructive work function measurements, a precision leak valve manifold for targeted adsorbate deposition, an inexpensive quadrupole mass spectrometer modified to perform high resolution temperature programmed desorption experiments and facilities to clean and characterize the surface.
International Nuclear Information System (INIS)
We report on the design and characterization of a new apparatus for performing quantum-state resolved surface scattering experiments. The apparatus combines optical state-specific molecule preparation with a compact hexapole and a Stark decelerator to prepare carrier gas-free pulses of quantum-state pure CO molecules with velocities controllable between 33 and 1000 m/s with extremely narrow velocity distributions. The ultrahigh vacuum surface scattering chamber includes homebuilt ion and electron detectors, a closed-cycle helium cooled single crystal sample mount capable of tuning surface temperature between 19 and 1337 K, a Kelvin probe for non-destructive work function measurements, a precision leak valve manifold for targeted adsorbate deposition, an inexpensive quadrupole mass spectrometer modified to perform high resolution temperature programmed desorption experiments and facilities to clean and characterize the surface
Inelastic electron scattering at low momentum transfer
International Nuclear Information System (INIS)
Recent advances of high energy resolution (ΔE approx. 30 keV FWHM) inelastic electron scattering at low momentum transfer (q -1) using selected experimental data from the Darmstadt electron linear accelerator are discussed. Strong emphasis is given to a comparison of the data with theoretical nuclear model predictions. Of the low multipolarity electric transitions investigated, as examples only E1 transitions to unnatural parity states in 11B and E2 transitions of the very fragmented isoscalar quadrupole giant resonance in 208Pb are considered. In 11B the role of the Os hole in the configuration of the 1/2+, 3/2+ and 5/2+ states is quantitatively determined via an interference mechanism in the transition probability. By comparison of the high resolution data with RPA calculations the E2 EWSR in 208Pb is found to be much less exhausted than anticipated from previous medium energy resolution (e,e) and hadron scattering experiments. In the case of M1 transitions it is shown that the simplest idealized independent particle shell-model prediction breaks down badly. In 28Si, ground-state correlations influence largely the detected M1 strength and such ground-state correlations are also responsible for the occurence of a strong M1 transition to a state at Ex = 10.319 MeV in 40Ca. In 90Zr only about 10% of the theoretically expected M1 strength is seen in (e,e) and in 140Ce and 208Pb none (detection limit 1-2 μ2K). In the case of 208Pb high resolution spectra exist now up to an excitation energy of Ex = approx. 12MeV. The continuous decrease of the M1 strength with mass number is corroborated by the behaviour of strong but very fragmented M2 transitions which are detected in 28Si, 90Zr, 140Ce and 208Pb concentrated at an excitation energy E x approx. 44A-1/3MeV. In 90Zr, the distribution of spacings and widths of the many Jπ = 2 states are consistent with a Wigner and Porter-Thomas distribution, respectively. (orig.) 891 KBE/orig. 892 ARA
Angular momentum transfer in deep inelastic scattering
International Nuclear Information System (INIS)
The measured γ-ray multiplicities as a function of exit channel kinetic energy and mass asymmetry for the reactions Au, Ho, Ag + 620 MeV Kr are compared with a diffusion calculation based exclusively upon particle transfer and which reproduces the Z distributions as well as the angular distributions as function of Z. The model correctly predicts the energy and Z dependence of the γ-ray multiplicities, thus lending support to the one-body model on one hand and to the angular-momentum fractionation along the mass asymmetry coordinate on the other
Parton models of high momentum transfer electron-nuclear scattering
International Nuclear Information System (INIS)
High-energy electron-nuclear scattering processes are discussed from the point of view of a parton model description. The light-cone formalism is introduced in a schematic presentation emphasizing: (i) the connection to relativistic dynamics, (ii) the phenomenological construction of the far off-shell components of wave functions, and (iii) asymptotic scaling laws. A survey is made of some of the recent calculations based on a nucleon constituent parton model and their comparison with data for momentum transfers Q22. A prospective discussion is also made on multiquark nuclear components and the quark parton model in QCD
Hayek, W; Carlsson, M; Trampedach, R; Collet, R; Gudiksen, B V; Hansteen, V H; Leenaarts, J
2010-01-01
We present the implementation of a radiative transfer solver with coherent scattering in the new BIFROST code for radiative magneto-hydrodynamical (MHD) simulations of stellar surface convection. The code is fully parallelized using MPI domain decomposition, which allows for large grid sizes and improved resolution of hydrodynamical structures. We apply the code to simulate the surface granulation in a solar-type star, ignoring magnetic fields, and investigate the importance of coherent scattering for the atmospheric structure. A scattering term is added to the radiative transfer equation, requiring an iterative computation of the radiation field. We use a short-characteristics-based Gauss-Seidel acceleration scheme to compute radiative flux divergences for the energy equation. The effects of coherent scattering are tested by comparing the temperature stratification of three 3D time-dependent hydrodynamical atmosphere models of a solar-type star: without scattering, with continuum scattering only, and with bo...
Hadron-hadron elastic scattering at large momentum transfers
International Nuclear Information System (INIS)
Cross sections for π+-p, K+-p and p+-p elastic scattering for incident momenta above a few tens of GeV/c and momentum transfers in the range 1 less than or equal to -t less than or equal to 10 (GeV/c)2 have recently been measured. The data are reviewed, and compared with existing models of elastic scattering
International Nuclear Information System (INIS)
Inversion of tropospheric profiles from ground-based microwave measurements requires a simple and accurate model for calculating the brightness temperatures as received by the radiometer. In the first part, an analytic solution of the radiative transfer equation is derived for an exponentially decaying absorption coefficient and a linear temperature gradient. Based on the obtained analytic expressions, a discretized radiative transfer scheme is developed in the second part. The new scheme incorporates the generic behavior of the atmosphere with the effect that brightness temperatures can be modeled more accurately and with fewer grid points compared to commonly used radiative transfer schemes. The brightness temperature modeling accuracy was improved by a factor of six. The results suggest that the model could be employed for the retrieval of temperature and humidity profiles.
Two mapping techniques for calculating radiative heat transfer with scattering
International Nuclear Information System (INIS)
This paper reports that the problem of radiative heat transfer through a gray, emitting, absorbing, and scattering medium with uniform optical properties is reduced to one without scattering through two techniques. One uses scaling laws, and the other uses a self-consistent effective gas temperature. The scaling laws are derived via the P1 approximation to the radiative transfer equation and can be applied to multidimensional problems with nonisothermal media. The effective temperature method is presently restricted to isotropic scattering and isothermal media. Both methods are evaluated in the current study as a function of scattering albedo, wall emissivity, and optical thickness for two different geometries, and two sets of wall and gas temperatures. The effects of scattering anisotropy are also assessed for the P1 method. The numerical results show that for these cases the scaling method is reasonably accurate for optically thick media with a scattering albedo less than 0.8, and the effective temperature technique is reasonably accurate for optically thin media for all albedos
Steady-state current transfer and scattering theory.
Ben-Moshe, Vered; Rai, Dhurba; Skourtis, Spiros S; Nitzan, Abraham
2010-08-01
The correspondence between the steady-state theory of current transfer and scattering theory in a system of coupled tight-binding models of one-dimensional wires is explored. For weak interwire coupling both calculations give nearly identical results, except at singular points associated with band edges. The effect of decoherence in each of these models is studied using a generalization of the Liouville-von Neuman equation suitable for steady-state situations. An example of a single impurity model is studied in detail, leading to a lattice model of scattering off target that affects both potential scattering and decoherence. For an impurity level lying inside the energy band, the transmission coefficient diminishes with increasing dephasing rate, while the opposite holds for impurity energy outside the band. The efficiency of current transfer in the coupled wire system decreases with increasing dephasing. PMID:20707524
International Nuclear Information System (INIS)
After having recalled that elastic electron scattering allows the determination of nucleus charge density with a high precision, and that a sufficiently high momentum transfer is required for the precision of analysis methods, this research thesis presents the results obtained by an experiment performed on 208Pb with a high momentum transfer. This nucleus meets at best the approximations required by theoretical calculations. In a first part, the author discusses the use of this nucleus, discusses the available data and outlines the lacking ones. He presents the experimental installation and aspects: the linear accelerator, the scattering angle, the solid angle, the number of incident neutrons, the target thermal toughness, and the number of elastically scattered neutrons. He reports the reduction of data: experiment-based corrections, radiative corrections, spectrum deconvolution methods, data normalisation, diaphragm aperture corrections and multiple scattering corrections. The next part proposes an analysis of data, and the last one compares the obtained results with theoretical ones
Fanelli, C; Hamilton, D J; Salme, G; Wojtsekhowski, B; Ahmidouch, A; Annand, J R M; Baghdasaryan, H; Beaufait, J; Bosted, P; Brash, E J; Butuceanu, C; Carter, P; Christy, E; Chudakov, E; Danagoulian, S; Day, D; Degtyarenko, P; Ent, R; Fenker, H; Fowler, M; Frlez, E; Gaskell, D; Gilman, R; Horn, T; Huber, G M; de Jager, C W; Jensen, E; Jones, M K; Kelleher, A; Keppel, C; Khandaker, M; Kohl, M; Kumbartzki, G; Lassiter, S; Li, Y; Lindgren, R; Lovelace, H; Luo, W; Mack, D; Mamyan, V; Margaziotis, D J; Markowitz, P; Maxwell, J; Mbianda, G; Meekins, D; Meziane, M; Miller, J; Mkrtchyan, A; Mkrtchyan, H; Mulholland, J; Nelyubin, V; Pentchev, L; Perdrisat, C F; Piasetzky, E; Prok, Y; Puckett, A J R; Punjabi, V; Shabestari, M; Shahinyan, A; Slifer, K; Smith, G; Solvignon, P; Subedi, R; Wesselmann, F R; Wood, S; Ye, Z; Zheng, X
2015-01-01
Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The WACS polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of \\cma$= 70^\\circ$. The longitudinal transfer \\KLL, measured to be $0.645 \\pm 0.059 \\pm 0.048$, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is $\\sim$3 times larger than predicted by the GPD-based calculations, which indicates a significant unknown contribution to the scattering amplitude.
Steady-state current transfer and scattering theory
Ben-Moshe, Vered; Rai, Dhurba; Skourtis, Spiros S.; Nitzan, Abraham
2010-01-01
The correspondence between the steady state theory of current transfer and scattering theory in a system of coupled tight-binding models of 1-dimensional wires is explored. For weak interwire coupling both calculations give nearly identical results, except at singular points associated with band edges. The effect of decoherence in each of these models is studied using a generalization of the Liouville-von Neuman equation suitable for steady-state situations. An example of a single impurity mo...
Radiative heat transfer in strongly forward scattering media using the discrete ordinates method
Granate, Pedro; Coelho, Pedro J.; Roger, Maxime
2016-03-01
The discrete ordinates method (DOM) is widely used to solve the radiative transfer equation, often yielding satisfactory results. However, in the presence of strongly forward scattering media, this method does not generally conserve the scattering energy and the phase function asymmetry factor. Because of this, the normalization of the phase function has been proposed to guarantee that the scattering energy and the asymmetry factor are conserved. Various authors have used different normalization techniques. Three of these are compared in the present work, along with two other methods, one based on the finite volume method (FVM) and another one based on the spherical harmonics discrete ordinates method (SHDOM). In addition, the approximation of the Henyey-Greenstein phase function by a different one is investigated as an alternative to the phase function normalization. The approximate phase function is given by the sum of a Dirac delta function, which accounts for the forward scattering peak, and a smoother scaled phase function. In this study, these techniques are applied to three scalar radiative transfer test cases, namely a three-dimensional cubic domain with a purely scattering medium, an axisymmetric cylindrical enclosure containing an emitting-absorbing-scattering medium, and a three-dimensional transient problem with collimated irradiation. The present results show that accurate predictions are achieved for strongly forward scattering media when the phase function is normalized in such a way that both the scattered energy and the phase function asymmetry factor are conserved. The normalization of the phase function may be avoided using the FVM or the SHDOM to evaluate the in-scattering term of the radiative transfer equation. Both methods yield results whose accuracy is similar to that obtained using the DOM along with normalization of the phase function. Very satisfactory predictions were also achieved using the delta-M phase function, while the delta
Ceolato, Romain; Riviere, Nicolas
2016-07-01
Spectral polarimetric light-scattering by particulate media has recently attracted growing interests for various applications due to the production of directional broadband light sources. Here the spectral polarimetric light-scattering signatures of particulate media are simulated using a numerical model based on the spectral Vector Radiative Transfer Equation (VRTE). A microphysical analysis is conducted to understand the dependence of the light-scattering signatures upon the microphysical parameters of particles. We reveal that depolarization from multiple scattering results in remarkable spectral and directional features, which are simulated by our model over a wide spectral range from visible to near-infrared. We propose to use these features to improve the inversion of the scattering problem in the fields of remote sensing, astrophysics, material science, or biomedical.
Neutron scattering investigation of magnetic excitations at high energy transfers
International Nuclear Information System (INIS)
With the advance of pulsed spallation neutron sources, neutron scattering investigation of elementary excitations in magnetic materials can now be extended to energies up to several hundreds of MeV. We have measured, using chopper spectrometers and time-of-flight techniques, the magnetic response functions of a series of d and f transition metals and compounds over a wide range of energy and momentum transfer. In PrO2, UO2, BaPrO3 and CeB6 we observed crystal-field transitions between the magnetic ground state and the excited levels in the energy range from 40 to 260 MeV. In materials exhibiting spin-fluctuation or mixed-valent character such as Ce 74Th 26, on the other hand, no sharp crystal-field lines but a broadened quasielastic magnetic peak was observed. The line width of the quasielastic component is thought to be connected to the spin-fluctuation energy of the 4f electrons. The significance of the neutron scattering results in relation to the ground state level structure of the magnetic ions and the spin-dynamics of the f electrons is discussed. Recently, in a study of the spin-wave excitations in itinerant magnetic systems, we have extended the spin-wave measurements in ferromagnetic iron up to about 160 MeV. Neutron scattering data at high energy transfers are of particular interest because they provide direct comparison with recent theories of itinerant magnetism. 26 references, 7 figures
Peregrinations through topics in light scattering and radiative transfer
Kattawar, George W.
2016-07-01
In this van de Hulst essay, I have taken the liberty to present a journey through some topics in light scattering and radiative transfer which I feel were major contributions to the field but the number of topics I would like to cover is far more numerous than I have the time or the space to present. I also wanted to share with the reader some heartwarming memories I have of my wonderful friend and truly distinguished colleague Hendrik Christoffel van de Hulst (affectionately known to his colleagues as "Henk") whom I consider to be one of the preeminent scientists of his era.
Froggatt, C D
1977-01-01
For pt.I see ibid., vol.104, p.186 (1976). The authors present final results for a pi pi phase-shift analysis based on extrapolated moments obtained from the 17 GeV/c CERN-Munich experiment on pi /sup -/p to pi /sup +/ pi /sup -/n. Compared to the previous publication the final results show no important qualitative change but the numerical accuracy is considerably improved as a result of using modified techniques both in the fixed-momentum transfer analysis and in the phase-shift analysis. As a result, various diseases of the old solution have been cured. They analyze in some detail the coupling of the rho '(1600) to 2 pi , clearly seen in the solution. It is argued that the technique has solved the phase-shift ambiguities previously obtained and details are given of the solution which has a very good chi /sup 2/ to the data as well as a high numerical consistency with fixed-t, fixed-u and fixed-s analyticity. (19 refs).
Direct collocation meshless method for vector radiative transfer in scattering media
International Nuclear Information System (INIS)
A direct collocation meshless method based on a moving least-squares approximation is presented to solve polarized radiative transfer in scattering media. Contrasted with methods such as the finite volume and finite element methods that rely on mesh structures (e.g. elements, faces and sides), meshless methods utilize an approximation space based only on the scattered nodes, and no predefined nodal connectivity is required. Several classical cases are examined to verify the numerical performance of the method, including polarized radiative transfer in atmospheric aerosols and clouds with phase functions that are highly elongated in the forward direction. Numerical results show that the collocation meshless method is accurate, flexible and effective in solving one-dimensional polarized radiative transfer in scattering media. Finally, a two-dimensional case of polarized radiative transfer is investigated and analyzed. - Highlights: • A direct collocation meshless method (DCM) is developed to solve VRTE. • The DCM is of high accuracy and excellent stability for solving VRTE. • Polarized radiative transfer with highly angular dependence is simulated exactly
Learning-based imaging through scattering media.
Horisaki, Ryoichi; Takagi, Ryosuke; Tanida, Jun
2016-06-27
We present a machine-learning-based method for single-shot imaging through scattering media. The inverse scattering process was calculated based on a nonlinear regression algorithm by learning a number of training object-speckle pairs. In the experimental demonstration, multilayer phase objects between scattering plates were reconstructed from intensity measurements. Our approach enables model-free sensing, where it is not necessary to know the sensing processes/models. PMID:27410537
Optimization of Plasmon Decay Through Scattering and Hot Electron Transfer
DeJarnette, Drew
Light incident on metal nanoparticles induce localized surface oscillations of conductive electrons, called plasmons, which is a means to control and manipulate light. Excited plasmons decay as either thermal energy as absorbed phonons or electromagnetic energy as scattered photons. An additional decay pathway for plasmons can exist for gold nanoparticles situated on graphene. Excited plasmons can decay directly to the graphene as through hot electron transfer. This dissertation begins by computational analysis of plasmon resonance energy and bandwidth as a function of particle size, shape, and dielectric environment in addition to diffractive coupled in lattices creating a Fano resonance. With this knowledge, plasmon resonance was probed with incident electrons using electron energy loss spectroscopy in a transmission electron microscope. Nanoparticles were fabricated using electron beam lithography on 50 nanometer thick silicon nitride with some particles fabricated with a graphene layer between the silicon nitride and metal structure. Plasmon resonance was compared between ellipses on and off graphene to characterize hot electron transfer as a means of plasmon decay. It was observed that the presence of graphene caused plasmon energy to decrease by as much as 9.8% and bandwidth to increase by 25%. Assuming the increased bandwidth was solely from electron transfer as an additional plasmon decay route, a 20% efficiency of plasmon decay to graphene was calculated for the particular ellipses analyzed.
Nuclear Transparency in Large Momentum Transfer Quasielastic Scattering
International Nuclear Information System (INIS)
We measured simultaneously pp elastic and quasielastic (p,2p) scattering in hydrogen, deuterium, and carbon for momentum transfers of 4.8 to 6.2 (GeV/c)2 at incoming momenta of 5.9 and 7.5 GeV/c and center-of-mass scattering angles in the range θc.m.=83.7 degree - 90 degree . The nuclear transparency is defined as the ratio of the quasielastic cross section to the free pp cross section. At incoming momentum of 5.9 GeV/c , the transparency of carbon decreases by a factor of 2 from θc.m.≅85 degree to θc.m.≅89 degree . At the largest angle the transparency of carbon increases from 5.9 to 7.5 GeV/c by more than 50%. The transparency in deuterium does not depend on incoming momentum nor on θc.m. . copyright 1998 The American Physical Society
International Nuclear Information System (INIS)
A comprehensive unified description of the application of Granada's Synthetic Model to the slow-neutron scattering by the molecular systems is continued. Detailed formulae for the zero-order energy transfer kernel are presented basing on the general formalism of the model. An explicit analytical formula for the total scattering cross section as a function of the incident neutron energy is also obtained. Expressions of the free gas model for the zero-order scattering kernel and for total scattering kernel are considered as a sub-case of the Synthetic Model. (author). 10 refs
Two-photon exchange correction to muon-proton elastic scattering at low momentum transfer
Energy Technology Data Exchange (ETDEWEB)
Tomalak, Oleksandr [Johannes Gutenberg Universitaet, Institut fuer Kernphysik, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany); Taras Shevchenko National University of Kyiv, Department of Physics, Kiev (Ukraine); Vanderhaeghen, Marc [Johannes Gutenberg Universitaet, Institut fuer Kernphysik, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany)
2016-03-15
We evaluate the two-photon exchange (TPE) correction to the muon-proton elastic scattering at small momentum transfer. Besides the elastic (nucleon) intermediate state contribution, which is calculated exactly, we account for the inelastic intermediate states by expressing the TPE process approximately through the forward doubly virtual Compton scattering. The input in our evaluation is given by the unpolarized proton structure functions and by one subtraction function. For the latter, we provide an explicit evaluation based on a Regge fit of high-energy proton structure function data. It is found that, for the kinematics of the forthcoming muon-proton elastic scattering data of the MUSE experiment, the elastic TPE contribution dominates, and the size of the inelastic TPE contributions is within the anticipated error of the forthcoming data. (orig.)
Two-photon exchange correction to muon-proton elastic scattering at small momentum transfer
Tomalak, O
2015-01-01
We evaluate the two-photon exchange (TPE) correction to the muon-proton elastic scattering at small momentum transfer. Besides the elastic (nucleon) intermediate state contribution, which is calculated exactly, we account for the inelastic intermediate states by expressing the TPE process approximately through the forward doubly virtual Compton scattering. The input in our evaluation is given by the unpolarized proton structure functions and by one subtraction function. For the latter, we provide an explicit evaluation based on a Regge fit of high-energy proton structure function data. It is found that,for the kinematics of the forthcoming muon-proton elastic scattering data of the MUSE experiment, the elastic TPE contribution dominates, and the size of the inelastic TPE contributions is within the anticipated error of the forthcoming data.
Two-photon exchange correction to muon-proton elastic scattering at low momentum transfer
Tomalak, Oleksandr; Vanderhaeghen, Marc
2016-03-01
We evaluate the two-photon exchange (TPE) correction to the muon-proton elastic scattering at small momentum transfer. Besides the elastic (nucleon) intermediate state contribution, which is calculated exactly, we account for the inelastic intermediate states by expressing the TPE process approximately through the forward doubly virtual Compton scattering. The input in our evaluation is given by the unpolarized proton structure functions and by one subtraction function. For the latter, we provide an explicit evaluation based on a Regge fit of high-energy proton structure function data. It is found that, for the kinematics of the forthcoming muon-proton elastic scattering data of the MUSE experiment, the elastic TPE contribution dominates, and the size of the inelastic TPE contributions is within the anticipated error of the forthcoming data.
International Nuclear Information System (INIS)
We present a single-scattering approximation for infrared radiative transfer in limb geometry in the Martian atmosphere. It is based on the assumption that the upwelling internal radiation field is dominated by a surface with a uniform brightness temperature. It allows the calculation of the scattering source function for individual aerosol types, mixtures of aerosol types, and mixtures of gas and aerosol. The approximation can be applied in a Curtis-Godson radiative transfer code and is used for operational retrievals from Mars Climate Sounder measurements. Radiance comparisons with a multiple scattering model show good agreement in the mid- and far-infrared although the approximate model tends to underestimate the radiances in realistic conditions of the Martian atmosphere. Relative radiance differences are found to be about 2% in the lowermost atmosphere, increasing to ∼10% in the middle atmosphere of Mars. The increasing differences with altitude are mostly due to the increasing contribution to limb radiance of scattering relative to emission at the colder, higher atmospheric levels. This effect becomes smaller toward longer wavelengths at typical Martian temperatures. The relative radiance differences are expected to produce systematic errors of similar magnitude in retrieved opacity profiles.
Havemann, Stephan; Thelen, Jean-Claude; Taylor, Jonathan P.; Keil, Andreas
2009-03-01
The Havemann-Taylor Fast Radiative Transfer Code (HT-FRTC) has been developed for the simulation of highly spectrally resolved measurements from satellite based (i.e. Infrared Atmospheric Sounding Interferometer (IASI), Atmospheric Infrared Sounder (AIRS)) and airborne (i.e. Atmospheric Research Interferometer Evaluation System (ARIES)) instruments. The use of principle components enables the calculation of a complete spectrum in less than a second. The principal compoents are derived from a diverse training set of atmospheres and surfaces and contain their spectral characteristics in a highly compressed form. For any given atmosphere/surface, the HT-FRTC calculates the weightings (also called scores) of a few hundred principal components based on selected monochromatic radiative transfer calculations, which is far cheaper than thousands of channel radiance calculations. By intercomparison with line-by-line and other fast models the HT-FRTC has been shown to be accurate. The HT-FRTC has been successfully applied to simultaneous variational retrievals of atmospheric temperature and humidity profiles, surface temperature and surface emissivity over land. This is the subject of another presentation at this conference. The HT-FRTC has now also been extended to include an exact treatment of scattering by aerosols/clouds. The radiative transfer problem is solved using a discrete ordinate method (DISORT). Modelling results at high-spectral resolution for non-clear sky atmospheres obtained with the HT-FRTC are presented.
Measurement of diffractive scattering of photons with large momentum transfer at HERA
Energy Technology Data Exchange (ETDEWEB)
Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania)]|[Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)
2008-09-15
The first measurement of diffractive scattering of quasi-real photons with large momentum transfer {gamma}p {yields} {gamma}Y, where Y is the proton dissociative system, is made using the H1 detector at HERA. The measurement is performed for initial photon virtualities Q{sup 2} < 0.01 GeV{sup 2}. Cross sections are measured as a function of W, the incident photonproton centre of mass energy, and t, the square of the four-momentum transferred at the proton vertex, in the range 175 < W < 247 GeV and 4 < vertical stroke t vertical stroke < 36 GeV{sup 2}. The W dependence is well described by a model based on perturbative QCD using a leading logarithmic approximation of the BFKL evolution. The measured vertical stroke t vertical stroke dependence is harder than that predicted by the model and those observed in exclusive vector meson production. (orig.)
Acoustic orbital angular momentum transfer to matter by chiral scattering
Wunenburger, Régis; Israel, Juan; Lozano, Vazquez; Brasselet, Etienne
2015-01-01
We report on orbital angular momentum exchange between sound and matter mediated by a non-dissipative chiral scattering process. An experimental demonstration is made possible by irradiating a three-dimensional printed, spiral-shaped chiral object with an incident ultrasonic beam carrying zero orbital angular momentum. Chiral refraction is shown to impart a nonzero orbital angular momentum to the scattered field and to rotate the object. This result constitutes a proof of concept of a novel k...
Acoustic orbital angular momentum transfer to matter by chiral scattering
Wunenburger, Régis; Israel Vazquez Lozano, Juan; Brasselet, Etienne
2015-10-01
We report on orbital angular momentum exchange between sound and matter mediated by a non-dissipative chiral scattering process. An experimental demonstration is made possible by irradiating a three-dimensional printed, spiral-shaped chiral object with an incident ultrasonic beam carrying zero orbital angular momentum. Chiral refraction is shown to impart a nonzero orbital angular momentum to the scattered field and to rotate the object. This result constitutes a proof of concept of a novel kind of acoustic angular manipulation of matter.
He, K.; Ludtke, S J; Wu, Y.; Huang, H W
1993-01-01
We demonstrate a technique for measuring x-ray (or neutron) scattering with the momentum transfer confined in the plane of membrane, for the purpose of studying lateral organization of proteins and peptides in membrane. Unlike freeze-fracture electron microscopy or atomic force microscopy which requires the membrane to be frozen or fixed, in-plane x-ray scattering can be performed with the membrane maintained in the liquid crystalline state. As an example, the controversial question of whethe...
A wave-mechanical model of incoherent neutron scattering II. Role of the momentum transfer
Frauenfelder, Hans; Fenimore, Paul W
2015-01-01
We recently introduced a wave-mechanical model for quasi-elastic neutron scattering (QENS) in proteins. We call the model ELM for "Energy Landscape Model". We postulate that the spectrum of the scattered neutrons consists of lines of natural width shifted from the center by fluctuations. ELM is based on two facts: Neutrons are wave packets; proteins have low-lying substates that form the free-energy landscape (FEL). Experiments suggest that the wave packets are a few hundred micrometers long. The interaction between the neutron and a proton in the protein takes place during the transit of the wave packet. The wave packet exerts the force $F(t) = dQ(t)/dt$ on the protein moiety, a part of the protein surrounding the struck proton. $Q(t)$ is the wave vector (momentum) transferred by the neutron wave packet to the proton during the transit. The ensuing energy is stored in the energy landscape and returned to the neutron as the wave packet exits. Kinetic energy thus is changed into potential energy and back. The ...
Outgoing Cuntz Scattering System for a Coisometric Lifting and Transfer Function
Indian Academy of Sciences (India)
Kalpesh J Haria
2013-08-01
We study a coisometry that intertwines Popescu’s presentations of minimal isometric dilations of a given operator tuple and of a coisometric lifting of the tuple. Using this we develop an outgoing Cuntz scattering system which gives rise to an input–output formalism. A transfer function is introduced for the system. We also compare the transfer function and the characteristic function for the associated lifting.
Photon conservation in scattering by large ice crystals with the SASKTRAN radiative transfer model
International Nuclear Information System (INIS)
The scattering of visible light by ice crystals and dust in radiative transfer models is challenging in part due to the large amount of scattering in the forward direction. We introduce a technique that ensures numerical conservation of photons in any radiative transfer model and that quantifies the integration error associated with highly asymmetric phase functions. When applied to a successive-orders of scatter model, the technique illustrates the high accuracy obtained in numerical integration of molecular and aerosol scattering. As well, a phase function truncation and renormalization technique is applied to scattering by ice crystals with very large size parameters, between 100 and 1000, and the scaled radiative transfer equation is solved with the spherical successive-orders model, SASKTRAN. Since computations shown this work are performed in a fully spherical model atmosphere, the computed radiances are not subject to the discontinuity at the horizon that is inherent in models using a plane-parallel assumption. The methods introduced in this work are of particular interest in modeling limb radiances in the presence of thin cirrus clouds.
International Nuclear Information System (INIS)
The investigation of the scattering of lower-hybrid waves by density fluctuations arising from drift waves in tokamaks is distinguished by the presence in the wave equation of a large, random, derivative-coupling term. The propagation of the lower-hybrid waves is well represented by a radiative transfer equation when the scale size of the density fluctuations is small compared to the overall plasma size. The radiative transfer equation is solved in two limits: first, the forward scattering limit, where the scale size of density fluctuations is large compared to the lower-hybrid perpendicular wavelength, and second, the large-angle scattering limit, where this inequality is reversed. The most important features of these solutions are well represented by analytical formulas derived by simple arguments. Based on conventional estimates for density fluctuations arising from drift waves and a parabolic density profile, the optical depth tau for scattering through a significant angle, is given by tauroughly-equal(2/N2/sub parallel/) (#betta#/sub p/i0/#betta#)2 (m/sub e/c2/2T/sub i/)/sup 1/2/ [c/α(Ω/sub i/Ω/sub e/)/sup 1/2/ ], where #betta#/sub p/i0 is the central ion plasma frequency and T/sub i/ denotes the ion temperature near the edge of the plasma. Most of the scattering occurs near the surface. The transmission through the scattering region scales as tau-1 and the emerging intensity has an angular spectrum proportional to cos theta, where sin theta = k/sub perpendicular/xB/sub p//(k/sub perpendicular/B/sub p/), and B/sub p/ is the poloidal field
Polarization imaging of multiply-scattered radiation based on integral-vector Monte Carlo method
International Nuclear Information System (INIS)
A new integral-vector Monte Carlo method (IVMCM) is developed to analyze the transfer of polarized radiation in 3D multiple scattering particle-laden media. The method is based on a 'successive order of scattering series' expression of the integral formulation of the vector radiative transfer equation (VRTE) for application of efficient statistical tools to improve convergence of Monte Carlo calculations of integrals. After validation against reference results in plane-parallel layer backscattering configurations, the model is applied to a cubic container filled with uniformly distributed monodispersed particles and irradiated by a monochromatic narrow collimated beam. 2D lateral images of effective Mueller matrix elements are calculated in the case of spherical and fractal aggregate particles. Detailed analysis of multiple scattering regimes, which are very similar for unpolarized radiation transfer, allows identifying the sensitivity of polarization imaging to size and morphology.
Two-photon exchange corrections in elastic lepton-proton scattering at small momentum transfer
Tomalak, Oleksandr; Vanderhaeghen, Marc
2016-03-01
In recent years, elastic electron-proton scattering experiments, with and without polarized protons, gave strikingly different results for the electric over magnetic proton form factor ratio. A mysterious discrepancy (``the proton radius puzzle'') has been observed in the measurement of the proton charge radius in muon spectroscopy experiments versus electron spectroscopy and electron scattering. Two-photon exchange (TPE) contributions are the largest source of the hadronic uncertainty in these experiments. We compare the existing models of the elastic contribution to TPE correction in lepton-proton scattering. A subtracted dispersion relation formalism for the TPE in electron-proton scattering has been developed and tested. Its relative effect on cross section is in the 1 - 2 % range for a low value of the momentum transfer. An alternative dispersive evaluation of the TPE correction to the hydrogen hyperfine splitting was found and applied. For the inelastic TPE contribution, the low momentum transfer expansion was studied. In addition with the elastic TPE it describes the experimental TPE fit to electron data quite well. For a forthcoming muon-proton scattering experiment (MUSE) the resulting TPE was found to be in the 0 . 5 - 1 % range, which is the planned accuracy goal.
Rybicki, G. B.; Hummer, D. G.
1994-10-01
Since the mass of the electron is very small relative to atomic masses, Thomson scattering of low-energy photons (hνatomic Doppler widths. A method is developed here to evaluate the electron scattering emissivity from a given radiation field which is considerably faster than previous methods based on straightforward evaluation of the scattering integral. This procedure is implemented in our multilevel radiative code (MALI), which now takes full account of the effects of noncoherent electron scattering on level populations, as well as on the emergent spectrum. Calculations using model atmospheres of hot, low-gravity stars display not only the expected broad wings of strong emission lines but also effects arising from the scattering of photons across continuum edges. In extreme cases this leads to significant shifts of the ionization equilibrium of helium.
np Pair transfer mechanism for backward elastic p 3He scattering at intermediate energies
International Nuclear Information System (INIS)
The two-body transfer mechanism for elastic rearrangement scattering from the three-body bound state i+{jkl}→j+{ikl} has been investigated on the basis of 4-dimensional formalism of covariant nonrelativistic graphs. The relation between this approach and the 3-dimensional graph formalism has been analyzed in detail. This approach is applied to describing backward elastic p 3He scattering in the energy range 0.5-1.7 GeV. The Faddeev 5-channel wave function is used for the bound state of the 3He nucleus. Numerical calculations show that the mechanism of sequential transfer of a noninteracting np-pair dominates while transfer of an interacting pair as well as nonsequential transfer of a noninteracting np-pair give a negligible contribution. The dominating mechanism is insensitive to the D-components of the 3He wave function and relativistic effects in spite of high momentum transfer. Taking into consideration Glauber rescatterings in the entrance and exit channels one obtains agreement with the experimental data in energy and angular dependence of the differential cross section at energies 0.9-1.7 GeV. (orig.)
Nucleon form factors for the elastic electron-deuteron scattering at high momentum transfer
Bekzhanov, A V; Burov, V V
2014-01-01
The reaction of the elastic electron-deuteron scattering at high momentum transfer is investigated within the Bethe-Salpeter approach. The relativistic covariant Graz II separable kernel of nucleon-nucleon interactions is used to analyze the deuteron structure functions, form factors and tensor of polarization components. The modern data for the electromagmetic nucleons structure from the double polarization experiments as well as some other models of the nucleon form factors are considered.
Vibrationally resolved inelastic and charge transfer scattering of H+ by H2O
International Nuclear Information System (INIS)
Inelastic and charge transfer scattering of protons by water molecules at collision energies of 27.0 and 46.0 eV have been investigated in a high-resolution crossed beam experiment up to the rainbow scattering angles. Excitation of the stretching (symmetric or asymmetric) and bending mode vibrations within the electronic ground state, X 1A1, of H2O was observed in the proton energy-loss spectra. In the case of charge transfer, formation of H2O+ in the X 2B1 and A 2A1 electronic states was identified in the corresponding H-atom spectra; the vibrational states within the X and A bands were for the most part resolved and, at small angles (θ≤20), they were found to be nearly the same as in photoionization (symmetric stretch and bending mode excitation within the X state and pure bending mode excitation within the A state). The vibronic transition probabilities deviate, however, considerably from the corresponding Franck--Condon factors in favor of the enhancement of the quasiresonant states. For both the inelastic and charge transfer scattering, state-selected quantities characteristic of the detailed collision dynamics have been derived. In addition, rotational excitation superimposed on the vibrational transitions could be estimated and for both processes it was found to be of the order of 50--100 meV
Zhang, Yong; Kim, Yong-Jun; Yi, Hong-Liang; Xie, Ming; Tan, He-Ping
2016-08-01
The natural element method (NEM) is extended to solve the polarized radiative transfer problem in a two-dimensional scattering medium with complex geometries, in which the angular space is discretized by the discrete-ordinates approach, and the spatial discretization is conducted by the Galerkin weighted residuals approach. The Laplace interpolation scheme is adopted to obtain the shape functions used in the Galerkin weighted residuals approach. The NEM solution to the vector radiative transfer in a square enclosure filled with a Mie scattering medium is first examined to validate our program. We then study the polarized radiative transfer in two kinds of geometries filled with scattering medium which is equivalent to a suspension of latex spheres in water. Three sizes of spheres are considered. The results for non-dimensional polarized radiative flux along the boundaries and the angular distributions of the Stokes vector at specific positions are presented and discussed. For the complex geometry bounded by the square and circular object, numerical solutions are presented for the cases both with Lambertian (diffuse) reflection and with Fresnel reflection. Some interesting phenomenon are found and analyzed.
Directory of Open Access Journals (Sweden)
T. Deutschmann
2009-04-01
Full Text Available We present a new technique for the quantitative simulation of the "Ring effect" for scattered light observations from various platforms and under different atmospheric situations. The method is based on radiative transfer calculations at only one wavelength λ_{0} in the wavelength range under consideration, and is thus computationally fast. The strength of the Ring effect is calculated from statistical properties of the photon paths for a given situation, which makes Monte Carlo radiative transfer models in particular appropriate. We quantify the Ring effect by the so called rotational Raman scattering probability, the probability that an observed photon has undergone a rotational Raman scattering event. The Raman scattering probability is independent from the spectral resolution of the instrument and can easily be converted into various definitions used to characterise the strength of the Ring effect. We compare the results of our method to the results of previous studies and in general good quantitative agreement is found. In addition to the simulation of the Ring effect, we developed a detailed retrieval strategy for the analysis of the Ring effect based on DOAS retrievals, which allows the precise determination of the strength of the Ring effect for a specific wavelength while using the spectral information within a larger spectral interval around the selected wavelength. Using our technique, we simulated synthetic satellite observation of an atmospheric scenario with a finite cloud illuminated from different sun positions. The strength of the Ring effect depends systematically on the measurement geometry, and is strongest if the satellite points to the side of the cloud which lies in the shadow of the sun.
Energy Technology Data Exchange (ETDEWEB)
Nukala, Madhuri [Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, SE 851 70, Sundsvall (Sweden); Mendrok, Jana [Department of Computer Science, Electrical and Space Engineering, Luleå University of Technology, Box 812, SE-98128 Kiruna (Sweden)
2014-12-10
Lateral light scattering simulations of printed dots are analyzed using general radiative transfer theory. We investigated the appearance of a printed paper in relation to the medium parameters like thickness of the paper sample, its optical properties, and the asymmetry factor. It was found that the appearance of a print greatly depends on these factors making it either brighter or darker. A thicker substrate with higher single scattering albedo backed with an absorbing surface makes the dots brighter due to increased number of scattering events. Additionally, it is shown that the optical effects of print also depend on illuminating and viewing angles along with the depth of ink penetration. A larger single scattering angle implies less intensity and the dots appear much blurred due to the shadowing effect prominent when viewed from sides. A fully penetrated dot of the same extinction coefficient as a partial penetrated one is darker due to increased absorption. These results can be used in applications dealing with lateral light scattering.
International Nuclear Information System (INIS)
Lateral light scattering simulations of printed dots are analyzed using general radiative transfer theory. We investigated the appearance of a printed paper in relation to the medium parameters like thickness of the paper sample, its optical properties, and the asymmetry factor. It was found that the appearance of a print greatly depends on these factors making it either brighter or darker. A thicker substrate with higher single scattering albedo backed with an absorbing surface makes the dots brighter due to increased number of scattering events. Additionally, it is shown that the optical effects of print also depend on illuminating and viewing angles along with the depth of ink penetration. A larger single scattering angle implies less intensity and the dots appear much blurred due to the shadowing effect prominent when viewed from sides. A fully penetrated dot of the same extinction coefficient as a partial penetrated one is darker due to increased absorption. These results can be used in applications dealing with lateral light scattering
International Nuclear Information System (INIS)
In order to improve the measurement performance of incoherent Thomson scattering diagnostics, a high performance phase conjugate mirror based on stimulated Brillouin scattering (SBS-PCM) is applied to a Thomson scattering system for the first time in the JT-60U tokamak. We have demonstrated that a SBS-PCM which uses heavy-fluorocarbon liquid showed a high reflectivity of 95% at a high input-power of 145 W. Using the SBS-PCM, two newly developed methods were employed to increase the amount of scattered light. In the first method, we first developed a new optical design to provide a double-pass scattering scheme with the SBS-PCM. In this new optical design, a laser beam passing through the plasma is reflected by the SBS-PCM, and the reflected beam is returned via the same path by means of the phase conjugate effect, and is then passed through the plasma again, in order to increase the scattered light. A double-pass Thomson scattering scheme using the SBS-PCM was demonstrated in JT-60U ohmic plasma, resulting in an increase of the scattered light by a factor of 1.6, and the reduction of relative error by 2/3 for electron temperature measurement in contrast to single-pass scattering. A multi-pass Thomson scattering scheme is also proposed based on the results of double-pass scattering. It is estimated that multi-pass scattering allows the generation of several times the amount of scattered light, and the reduction of the relative error for electron temperature measurement by 37% in contrast to single-pass scattering. Regarding the second method, a high average-power of YAG laser system was developed by applying the SBS-PCM to a existent diagnostic laser. As a result, the average-power was increased by over 8 times in contrast to the average power of the original system, achieving up to 368 W (7.4 J x 50 Hz). (author)
Dust aerosol forward scattering effects on ground-based aerosol optical depth retrievals
International Nuclear Information System (INIS)
Monte Carlo radiative transfer calculations are performed to examine the forward scattering effects on retrievals of dust aerosol optical depth (AOD) from ground-based instruments. We consider dust aerosols with different AOD, effective radius and imaginary refractive index at 0.5 μm wavelength. The shape of dust aerosols is assumed to be spheroids and the equivalent spheres that preserve both volume and projected area (V/P) are also considered. The single-scattering albedos and asymmetry factors of spheroids and V/P-equivalent spheres have small differences, but the scattering phase functions are very different for the scattering angle range ∼90-180o. The relative errors of retrieved AOD caused by forward scattering effects due to the differences between the single-scattering properties of spheroids and spheres are similar. It is shown that at solar zenith angle (SZA) smaller than ∼70o the effect of the forward scattering is generally small although the relative errors in retrieved AOD can be as large as -10% when re=2. However, the largest relative errors, which can reach -40%, appear at high SZA (>∼70o) with AOD larger than 1. This is not caused by the increase of forward scattering intensity, but is due to the strong attenuation of solar direct beam.
International Nuclear Information System (INIS)
The verification of a new or updated radiative transfer model (RTM) is one of the important steps in its development; this is usually achieved by comparisons with real measurements or published tables of generally accepted radiative transfer results. If such tables do not exist, verification becomes more complicated and an external review of the implementation is often unpractical due to the sheer amount and complexity of the code. The presented verification approach is to “simply” insert results of radiative transfer (RT) calculations into the radiative transfer equation (RTE). The evaluation of the RTE consists of numerically calculating partial derivatives and integrals, which is much simpler to implement than a solution of the RTE. Presented is a demonstration of this approach for a case of Rayleigh scattering in a plane parallel atmosphere, which showed only very small deviation from the radiative transfer equation. This approach has two key benefits. First, its implementation into a high level computer language can be very short (≈60 lines in MATHEMATICA) and clear compared to a full RTM; and such code is much more easy to review. Second, this approach can be easily extended to cases where no other independent RT implementation is available for validation. The proposed implementation and data are provided with this paper. -- Highlights: ► Radiative transfer results are verified by numerically inserting them into the RTE. ► This approach is demonstrated using a Rayleigh scattering test case. ► The implementation of such verification scheme is simple, short, and clear. ► The scheme and the demonstration data set is provided with the paper.
Ustinov, Y. A.
1978-01-01
The direct method for the solution of the spherical harmonics approximation to the equation of transfer of radiation is applied to the cases of (1) scattering of the solar radiation in the atmosphere with the Lambertian boundary and (2) thermal radiation transfer.
Compton Scattering by Static and Moving Media; 1, the Transfer Equation and Its Moments
Psaltis, D; Psaltis, Dimitrios; Lamb, Frederick K.
1997-01-01
Compton scattering of photons by nonrelativistic particles is thought to play an important role in forming the radiation spectrum of many astrophysical systems. Here we derive the time-dependent photon kinetic equation that describes spontaneous and induced Compton scattering as well as absorption and emission by static and moving media, the corresponding radiative transfer equation, and their zeroth and first moments, in both the system frame and in the frame comoving with the medium. We show that it is necessary to use the correct relativistic differential scattering cross section in order to obtain a photon kinetic equation that is correct to first order in epsilon/m_e, T_e/m_e, and V, where epsilon is the photon energy, T_e and m_e are the electron temperature and rest mass, and V is the electron bulk velocity in units of the speed of light. We also demonstrate that the terms in the radiative transfer equation that are second-order in V usually should be retained, because if the radiation energy density i...
International Nuclear Information System (INIS)
Coupled radiative-conductive heat transfer inside an absorbing-emitting-scattering semitransparent slab is solved. The refractive index of the media is distributed spatially in a linear relationship. The two boundary surfaces are diffuse and opaque. In this paper, the media with graded refractive index is simulated by using multilayer composite model, and in each sub-layer the refractive index is supposed to be constant and the rays of thermal radiation travel in a straight line. The multilayer model is developed by ray-tracing method combined with node analysis. A comparison of the present results with previous results shows that the multilayer simulation of media with graded refractive index is rational and correct. Considering isotropic scattering of thermal radiation, with the changes in the extinction coefficient, surface emissivities and the scattering albedo, the influences of refractive index distribution on the temperature and the radiative heat flux fields are investigated. The results show that the gradient distributing of refractive indexes can cause very different thermal behavior concerned with radiative transfer in semitransparent media compared with constant refractive indexes
A Multiple Scattering Polarized Radiative Transfer Model: Application to HD 189733b
Kopparla, Pushkar; Zhang, Xi; Swain, Mark R; Wiktorowicz, Sloane J; Yung, Yuk L
2015-01-01
We present a multiple scattering vector radiative transfer model which produces disk integrated, full phase polarized light curves for reflected light from an exoplanetary atmosphere. We validate our model against results from published analytical and computational models and discuss a small number of cases relevant to the existing and possible near-future observations of the exoplanet HD 189733b. HD 189733b is arguably the most well observed exoplanet to date and the only exoplanet to be observed in polarized light, yet it is debated if the planet's atmosphere is cloudy or clear. We model reflected light from clear atmospheres with Rayleigh scattering, and cloudy or hazy atmospheres with Mie and fractal aggregate particles. We show that clear and cloudy atmospheres have large differences in polarized light as compared to simple flux measurements, though existing observations are insufficient to make this distinction. Futhermore, we show that atmospheres that are spatially inhomogeneous, such as being partial...
A hybrid transport-diffusion model for radiative transfer in absorbing and scattering media
International Nuclear Information System (INIS)
A new multi-scale hybrid transport-diffusion model for radiative transfer is proposed in order to improve the efficiency of the calculations close to the diffusive regime, in absorbing and strongly scattering media. In this model, the radiative intensity is decomposed into a macroscopic component calculated by the diffusion equation, and a mesoscopic component. The transport equation for the mesoscopic component allows to correct the estimation of the diffusion equation, and then to obtain the solution of the linear radiative transfer equation. In this work, results are presented for stationary and transient radiative transfer cases, in examples which concern solar concentrated and optical tomography applications. The Monte Carlo and the discrete-ordinate methods are used to solve the mesoscopic equation. It is shown that the multi-scale model allows to improve the efficiency of the calculations when the medium is close to the diffusive regime. The proposed model is a good alternative for radiative transfer at the intermediate regime where the macroscopic diffusion equation is not accurate enough and the radiative transfer equation requires too much computational effort
International Nuclear Information System (INIS)
The ponderomotive momentum exchange in laser interaction with electrons is derived using a scattering model. This explains how the momentum is exchanged globally when an electron is emitted radially from a laser beam while the axial exchange of momentum is coupled with the momentum of the electromagnetic energy transferred from the laser field to the electron in the form of kinetic energy. Special attention is given to the forces acting on electrons in a laser beam and expelling the electrons laterally from the beam. 14 refs
Abbott, D
2000-01-01
Tensor polarization observables (t20, t21 and t22) have been measured in elastic electron-deuteron scattering for six values of momentum transfer between 0.66 and 1.7 (GeV/c)^2. The experiment was performed at the Jefferson Laboratory in Hall C using the electron HMS Spectrometer, a specially designed deuteron magnetic channel and the recoil deuteron polarimeter POLDER. The new data determine to much larger Q^2 the deuteron charge form factors G_C and G_Q. They are in good agreement with relativistic calculations and disagree with pQCD predictions.
Garçon, M; Ahmidouch, A; Anklin, H; Arvieux, J; Ball, J; Beedoe, S; Beise, E J; Bimbot, L; Böglin, W; Breuer, H; Carlini, R; Chant, N S; Danagulyan, S; Dow, K; Ducret, J E; Dunne, J; Ewell, L A; Eyraud, L; Furget, C; Gilman, R; Glashausser, C; Gueye, P; Gustafsson, K K; Hafidi, K; Honegger, A; Jourdan, J; Kox, S; Kumbartzki, G; Lü, L; Lung, A; Mack, D; Markowitz, P; McIntyre, J; Meekins, D; Merchez, F; Mitchell, J; Möhring, R H; Mtingwa, S; Mrktchyan, H; Pitz, D; Qin, L; Ransome, R; Real, J S; Roos, P G; Rutt, P; Schmidt, W; Sawafta, R; Stepanyan, S; Stephenson, E J; Tieulent, R; Tomasi-Gustafsson, E; Turchinetz, W E; Vansyoc, K; Volmer, J; Voutier, E; Vulcan, W; Williamson, C; Wood, S A; Yan, C; Zhao, J; Zhao, W
1999-01-01
In elastic electron-deuteron scattering, the tensor polarization moments t sub 2 sub 0 , t sub 2 sub 1 and t sub 2 sub 2 , together with the unpolarized cross-sections, have been measured up to a momentum transfer of 1.8 (GeV/c) sup 2 , or 6.8 fm sup - sup 1. The experiment was performed at Jefferson Laboratory using the recoil deuteron polarimeter POLDER. Preliminary results are presented and discussed, especially in view of their significance concerning the applicability of perturbative QCD to this exclusive process.
Multi-coupled single scattering method of solving vector radiative transfer equations
Institute of Scientific and Technical Information of China (English)
Sun Bin; Wang Han; Sun Xiao-Bing; Hong Jin; Zhang Yun-Jie
2012-01-01
A new method of multi-coupled single scattering (MCSS) for solving a vector radiative transfer equation is developed and made public on Internet.Recent solutions from Chandrasekhar's X-Y method is used to validate the MCSS's result,which shows high precision.The MCSS method is theoretically simple and clear,so it can be easily and credibly extended to the simulation of aerosol/cloud atmosphere's radiative properties,which provides effective support for research into polarized remote sensing.
International Nuclear Information System (INIS)
A plane parallel vector radiative transfer model is presented to simulate the effect of rotational Raman scattering on radiance and polarization properties of sunlight reflected by the Earth atmosphere in the ultraviolet and visible part of the solar spectrum. The model employs the radiative transfer perturbation theory, which treats inelastic rotational Raman scattering as a perturbation to elastic Rayleigh scattering. The approach provides a perturbation series expansion for a simulated radiation quantity, where each term describes the effect of one additional order of Raman scattering. The model is worked out in detail to first order. Here, the adjoint formulation of radiative transfer reduces significantly the numerical effort of computational applications. Numerical simulations are presented for the ultraviolet part of the solar spectrum and the effect of Raman scattering on the Stokes parameters I,Q and U of the reflected sunlight is studied. Furthermore, the accuracy of both the single scattering approximation and the scalar radiative transfer approach is considered for the simulation of Ring structures. The use of these approximation techniques is investigated for the simulation of Ring structures in polarization sensitive GOME measurements
Longitudinal spin transfer to the Λ hyperon in semi-inclusive deep-inelastic scattering
International Nuclear Information System (INIS)
The transfer of polarization from a high-energy positron to a Λ0 hyperon produced in semi-inclusive deep-inelastic scattering has been measured. The data have been obtained by the HERMES experiment at DESY using the 27.6 GeV longitudinally polarized positron beam of the HERA collider and unpolarized gas targets internal to the positron (electron) storage ring. The longitudinal spin transfer coefficient is found to be DΛLL'=0.11±0.10(stat)±0.03(syst) at an average fractional energy carried by the Λ0 hyperon left angle z right angle =0.45. The dependence of DΛLL' on both the fractional energy z and the fractional longitudinal momentum xF is presented. (Orig.)
Longitudinal Spin Transfer to the $\\Lambda$ Hyperon in Semi-Inclusive Deep-Inelastic Scattering
Airapetian, A; Akopov, Z; Amarian, M; Andrus, A; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetisian, A; Avetissian, E; Bailey, P; Balin, D; Beckmann, M; Belostotskii, S; Bianchi, N; Blok, H P; Böttcher, Helmut B; Borisov, A; Borysenko, A; Bouwhuis, M; Brüll, A; Bryzgalov, V; Capiluppi, M; Capitani, G P; Chen, T; Chen, X; Chiang, H C; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; Deconinck, W; De Leo, R; Demey, M; De Nardo, L; De Sanctis, E; Devitsin, E; Diefenthaler, M; Di Nezza, P; Dreschler, J; Düren, M; Ehrenfried, M; Elalaoui-Moulay, A; Elbakian, G; Ellinghaus, F; Elschenbroich, U; Fabbri, R; Fantoni, A; Felawka, L; Frullani, S; Funel, A; Gapienko, G; Gapienko, V; Garibaldi, F; Garrow, K; Gavrilov, G; Karibian, V; Grebenyuk, O; Gregor, I M; Hadjidakis, C; Hafidi, K; Hartig, M; Hasch, D; Hesselink, W H A; Hillenbrand, A; Hoek, M; Holler, Y; Hommez, B; Hristova, I; Iarygin, G; Ivanilov, A; Izotov, A; Jackson, H E; Jgoun, A; Kaiser, R; Keri, T; Kinney, E; Kiselev, A; Kobayashi, T; Kopytin, M; Korotkov, V; Kozlov, V; Krauss, B; Kravchenko, P; Krivokhizhin, V G; Lagamba, L; Lapikas, L; Laziev, A; Lenisa, P; Liebing, P; Linden-Levy, L A; Lorenzon, W; Lü, H; Lü, J; Lu, S; Lü, X; Ma, B Q; Maiheu, B; Makins, N C R; Manaenkov, S I; Mao, Y; Marianski, B; Marukyan, H; Masoli, F; Mexner, V; Meyners, N; Michler, T; Miklukho, O; Miller, C A; Miyachi, Y; Muccifora, V; Murray, M; Nagaitsev, A; Nappi, E; Naryshkin, Yu; Negodaev, M; Nowak, Wolf-Dieter; Oganessyan, K; Ohsuga, H; Osborne, A; Pickert, N; Potterveld, D H; Raithel, M; Reggiani, D; Reimer, P E; Reischl, A; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubacek, L; Rubin, J; Ryckbosch, D; Salomatin, Y; Sanjiev, I; Savin, I; Schäfer, A; Schnell, G; Schüler, K P; Seele, J; Seidl, R; Seitz, B; Shearer, C; Shibata, T A; Shutov, V; Sinram, K; Sommer, W; Stancari, M; Statera, M; Steffens, E; Steijger, J J M; Stenzel, H; Stewart, J; Stinzing, F; Tait, P; Tanaka, H; Taroian, S P; Tchuiko, B; Terkulov, A R; Trzcinski, A; Tytgat, M; Vandenbroucke, A; Van der Nat, P B; van der Steenhoven, G; Van Haarlem, Y; Vikhrov, V; Vincter, M G; Vogel, C; Volmer, J; Wang, S; Wendland, J; Ye, Y; Ye, Z; Yen, S; Zihlmann, B; Zupranski, P
2006-01-01
The transfer of polarization from a high-energy positron to a \\lam hyperon produced in semi-inclusive deep-inelastic scattering has been measured. The data have been obtained by the HERMES experiment at DESY using the 27.6 GeV longitudinally polarized positron beam of the HERA collider and unpolarized gas targets internal to the positron (electron) storage ring. The longitudinal spin transfer coefficient is found to be $\\dll = 0.11 \\pm 0.10 \\mathrm{(stat)} \\pm 0.03 \\mathrm{(syst)}$ at an average fractional energy carried by the \\lam hyperon $= 0.45$. The dependence of \\dll on both the fractional energy $z$ and the fractional longitudinal momentum $x_F$ is presented.
International Nuclear Information System (INIS)
The curved ray tracing method (CRT) is extended to radiative transfer in the linear-anisotropic scattering medium with graded index from non-scattering medium. In this paper, the CRT is presented to solve one-dimensional radiative transfer in the linear-anisotropic scattering gray medium with a linear refractive index and two black boundaries. The predicted temperature distributions and radiative heat flux at radiative equilibrium are determined by the proposed method, and numerical results are compared with the data in references. The results show that the CRT has a good accuracy for radiative transfer in the linear-anisotropic scattering medium with graded index and the dimensionless emissive power and dimensionless radiative heat flux depend on the dimensionless refractive index gradient. It can also be seen that the dimensionless refractive index gradient has important effects on the temperature discontinuity at the boundaries.
International Nuclear Information System (INIS)
The successive order scattering approximation method is used to study the radiative transfer equation. By separating the coherent component of the scattered flux, the transport equation is represented in terms of each order scattering flux and a simplified solution is obtained with this approach. The method is then used to calculate the reflected flux and the transmitted flux with three different phase functions. A new boundary condition has been added for the first order forwardly scattered flux. Thus it becomes possible to study the transmittance. We compare our results with the available data for a biological medium. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Akcay, Huseyi [Baskent Univ. Baglica Kampusu, Ankara (Turkey)
2012-03-15
The successive order scattering approximation method is used to study the radiative transfer equation. By separating the coherent component of the scattered flux, the transport equation is represented in terms of each order scattering flux and a simplified solution is obtained with this approach. The method is then used to calculate the reflected flux and the transmitted flux with three different phase functions. A new boundary condition has been added for the first order forwardly scattered flux. Thus it becomes possible to study the transmittance. We compare our results with the available data for a biological medium. (orig.)
International Nuclear Information System (INIS)
Analyzing powers and spin transfer coefficients which describe the elastic scattering of polarized protons from a polarized deuteron target have been measured. The energy of the proton beam was 800 MeV and data were taken at laboratory scattering angles of 7, 11, 14, and 16.5 degrees. One analyzing power was also measured at 180 degrees. Three linearly independent orientations of the beam polarization were used and the target was polarized parallel and antiparallel to the direction of the beam momentum. The data were taken with the high resolution spectrometer at the Los Alamos Meson Physics Facility (experiment 685). The results are compared with multiple scattering predictions based on Dirac representations of the nucleon-nucleon scattering matrices. 27 refs., 28 figs., 4 tabs
Towards a Precision Measurement of Parity-Violating e-p Elastic Scattering at Low Momentum Transfer
Energy Technology Data Exchange (ETDEWEB)
Pan, Jie [Univ. of Manitoba, Winnipeg (Canada)
2012-01-01
The goal of the Q-weak experiment is to make a measurement of the proton's weak charge Q_{W}^{p} = 1 - 4 sin^{2}(θ_{W2(θW2(θWWp by measuring the parity violating asymmetry in elastic electron-proton scattering at low momentum transfer Q2 = 0.026 (GeV/c)2 and forward angles (8 degrees). The anticipated size of the asymmetry, based on the SM, is about 230 parts per billion (ppb). With the proposed accuracy, the experiment may probe new physics beyond Standard Model at the TeV scale. This thesis focuses on my contributions to the experiment, including track reconstruction for momentum transfer determination of the scattering process, and the focal plane scanner, a detector I designed and built to measure the flux profile of scattered electrons on the focal plane of the Q-weak spectrometer to assist in the extrapolation of low beam current tracking results to high beam current. Preliminary results from the commissioning and the first run period of the Q-weak experiment are reported and discussed.}
Charge Transfer and Surface Scattering at Cu/C_60 Planar Interfaces
Hebard, A. F.; Ruel, R. R.; Eom, C. B.
1996-03-01
Thin films of Cu and C_60 have been sequentially deposited onto insulating substrates in high vacuum and studied using in situ resistivity measurements during deposition. Different regimes of behavior, which manifest the transfer of electrons from the Cu metal across the planar interface to the C_60, are identified. For example, in the continuous film limit, in which the Cu is thick enough to have a size-effect resistivity proportional to the reciprocal of the film thickness, the presence of an adjacent C_60 monolayer gives rise to an increase in resistance. This resistance increase is quantitatively described by a scattering model in which the interfacial diffuse scattering cross section is found to be 5Åthe approximate area of a face of the molecular cage. In a second regime of behavior, in which the ultra-thin Cu films have a morphology of coalescing islands, the presence of an adjacent C_60 monolayer, doped by charge transfer from the metal, creates a shunting path with sheet resistance ~8000Ω/Box accompanied by a pronounced decrease in resistance. The inferred room-temperature resistivity is more than a factor of two less than that of the 3-dimensional alkali-metal-doped compounds, A_3C_60 (A=K,Rb).
Directory of Open Access Journals (Sweden)
S Amiri
2016-02-01
Full Text Available In the present work the first and second order scattering amplitudes and the related phase were calculated in the charge transfer channel. The positronium formation, with the impact of molecular hydrogen ion, has been carried out using multiple channel scattering formulation and transition matrix. The calculation of differential cross section has been done by varying the scattering angle from 0 to 180 in the fixed orientation of the molecule. In the next calculation the scattering angles were fixed while the spatial molecular orientation was varied. At last the calculated differential cross section was compared with available results in the literature. The scattering angle spanned from 0 to 180 degrees in the second order nuclear and electronic terms were calculated while the molecular orientation was assumed to be fixed. Otherwise, the scattering angles were fixed in the calculation of the corresponding amplitudes while the orientation was varied. At last our calculations were compared with available results
Thermal invisibility based on scattering cancellation and mantle cloaking
Farhat, M.; Chen, P.-Y.; H. Bagci; Amra, Claude; Guenneau, Sébastien; Alu, A.
2015-01-01
We theoretically and numerically analyze thermal invisibility based on the concept of scattering cancellation and mantle cloaking. We show that a small object can be made completely invisible to heat diffusion waves, by tailoring the heat conductivity of the spherical shell enclosing the object. This means that the thermal scattering from the object is suppressed, and the heat flow outside the object and the cloak made of these spherical shells behaves as if the object is not present. Thermal...
International Nuclear Information System (INIS)
Hamamatsu SHR74000 is a newly designed full three-dimensional (3D) whole body positron emission tomography (PET) scanner with small crystal size and large field of view (FOV). With the improvement of sensitivity, the scatter events increase significantly at the same time, especially for large objects. Monte Carlo simulations help us to understand the scatter phenomena and provide good references for scatter correction. In this paper, we introduce an effective scatter correction method based on single scatter simulation for the new PET scanner, which accounts for the full 3D scatter correction. With the results from Monte Carlo simulations, we implement a new scale method with special concentration on scatter events from outside the axial FOV and multiple scatter events. The effects of scatter correction are investigated and evaluated by phantom experiments; the results show good improvements in quantitative accuracy and contrast of the images, even for large objects. (condensed matter: electronic structure, electrical, magnetic, and optical properties)
International Nuclear Information System (INIS)
This note serves as an introduction to two papers by Klose et al. and provides a brief review of the latest developments in optical tomography of scattering tissue. We discuss advancements made in solving the forward model for light propagation based on the radiative transfer equation, in reconstructing scattering and absorption cross sections of tissue, and in molecular imaging of luminescent sources.
Transfer Prototype-based Fuzzy Clustering
Deng, Zhaohong; Jiang, Yizhang; Chung, Fu-Lai; Ishibuchi, Hisao; Choi, Kup-Sze; Wang, Shitong
2014-01-01
The traditional prototype based clustering methods, such as the well-known fuzzy c-mean (FCM) algorithm, usually need sufficient data to find a good clustering partition. If the available data is limited or scarce, most of the existing prototype based clustering algorithms will no longer be effective. While the data for the current clustering task may be scarce, there is usually some useful knowledge available in the related scenes/domains. In this study, the concept of transfer learning is a...
Scatter-based magnetic resonance elastography
International Nuclear Information System (INIS)
Elasticity is a sensitive measure of the microstructural constitution of soft biological tissues and increasingly used in diagnostic imaging. Magnetic resonance elastography (MRE) uniquely allows in vivo measurement of the shear elasticity of brain tissue. However, the spatial resolution of MRE is inherently limited as the transformation of shear wave patterns into elasticity maps requires the solution of inverse problems. Therefore, an MRE method is introduced that avoids inversion and instead exploits shear wave scattering at elastic interfaces between anatomical regions of different shear compliance. This compliance-weighted imaging (CWI) method can be used to evaluate the mechanical consistency of cerebral lesions or to measure relative stiffness differences between anatomical subregions of the brain. It is demonstrated that CWI-MRE is sensitive enough to reveal significant elasticity variations within inner brain parenchyma: the caudate nucleus (head) was stiffer than the lentiform nucleus and the thalamus by factors of 1.3 ± 0.1 and 1.7 ± 0.2, respectively (P < 0.001). CWI-MRE provides a unique method for characterizing brain tissue by identifying local stiffness variations.
International Nuclear Information System (INIS)
The authors discuss two projects involving quantal collision theory calculations on supercomputers. In the first project the authors are considering HF-HF collisions and calculating rotational energy transfer for collisions of rigid molecules and vibrational-to-vibrational (V-V) energy transfer for collisions including all degrees of freedom. They examined several potential energy surfaces, and they parametrized a new one that should be more accurate for the cross correlation of the forces. For rotational energy transfer they also compared the results to classical trajectory calculations. The quantal calculations were carried out by integrating the close coupling equations with scattering boundary conditions using an extensively vectorized R matrix propagation code on the Control Data Corporation Cyber 205 computer. In the second project they are considering atom-diatom reactive collisions for low initial rotational states and both the ground and first excited vibrational state. The three arrangement channels (A =BC, AB+C, and AC+B) are coupled by the Fock scheme, and the reactive amplitude density (obtained by operating on the initial state with the reactance operator or the total wave function with the interaction potential) is expanded in a square-integrable basis set. This leads to a large system of coupled algebraic equations which are constructed and solved using a large-memory Cray-2 computer. Variational improvements have been tested successfully for nonreactive collisions and will soon be implemented for reactive collisions
Geometric Feature Extraction and Model Reconstruction Based on Scattered Data
Institute of Scientific and Technical Information of China (English)
胡鑫; 习俊通; 金烨
2004-01-01
A method of 3D model reconstruction based on scattered point data in reverse engineering is presented here. The topological relationship of scattered points was established firstly, then the data set was triangulated to reconstruct the mesh surface model. The curvatures of cloud data were calculated based on the mesh surface, and the point data were segmented by edge-based method; Every patch of data was fitted by quadric surface of freeform surface, and the type of quadric surface was decided by parameters automatically, at last the whole CAD model was created. An example of mouse model was employed to confirm the effect of the algorithm.
Plasmon Resonance Energy Transfer (PRET)-based Molecular Imaging of Cytochrome c in Living Cells
Choi, Yeonho; Kang, Taewook; Lee, Luke P.
2009-01-01
We describe the development of innovative plasmon resonance energy transfer (PRET)-based molecular imaging of biomolecules in living cells. Our strategy of in vivo PRET imaging relies on the resonant plasmonic energy transfer from a gold nanoplasmonic probe to conjugated target molecules, which creates “quantized quenching dips” within the Rayleigh scattering spectrum of the probe. The positions of these quantized quenching dips exactly match with the absorption peaks of the target molecule s...
Inelastic scattering and multinucleon transfer in 3,4He + 9Be reactions
International Nuclear Information System (INIS)
A study of inelastic scattering and multinucleon transfer reactions was performed by α and 3He beams on a 9Be target at energy about 50 MeV. Angular distributions of the differential cross sections for the 9Be(α, α)9Be*, 9Be(α, 3He)10Be, 9Be(α, t)10B, 9Be(3He, 6Li)6Li, and 9Be(3He, 6Be)6He reactions were measured. Experimental angular distributions of the differential cross sections for the ground state and a few low-lying states were analyzed in the framework of the optical model, coupled channels, and distorted-wave Born approximation. The information on the cluster structure of the reaction products was obtained. The analysis of the obtained spectroscopic factors was performed
Continuous Stochastic Radiative Transfer with Rayleigh Scattering in Semi-Infinite Atmospheric Media
International Nuclear Information System (INIS)
The radiative transfer problem in a semi-infinite stochastic atmospheric medium with Rayleigh scattering is studied. The extinction function (cross section) of the medium is assumed to be a continuous random function of position, with fluctuations about the mean taken as Gaussian distributed. The joint probability distribution function of these Gaussian random variables is used to calculate the ensemble-averaged quantities, such as radiant energy and net flux, for an arbitrary correlation function. The deterministic solution of the considered problem is obtained at first. Then the solution is averaged using Gaussian joint probability distribution function. A modified Gaussian probability distribution function is also used to average the solution. Numerical results are given for the sake of comparison.
Bairamov, B. Kh.
2016-04-01
This paper reports on the formation of complexes consisting of isolated free-standing crystalline semiconductor quantum dots, for example, nc-Si/SiO2, functionalized by short oligonucleotides, for example, the single-stranded system d(20G, 20T). Here, d are deoxyribonucleotides, G and T are guanine and thymine nucleotides, respectively. It has been found that these complexes are unique objects for the elucidation of the specific features in the manifestation of new quantum-size effects in biomacromolecules. It has been demonstrated that the possibility exists of detecting and recording, in such complexes of biomacromolecules, spectrally selective resonance enhancement of Raman scattering intensity in fluctuations of nucleotide molecules due to coherent nonradiative transfer of a photoexcited electron and a hole at the interface of the complex. This dynamic optical imaging of spectral responses can be of applied interest for the development of nanobiophotonic technologies.
Atomic scattering in the diffraction limit: electron transfer in keV Li+-Na(3s, 3p) collisions
DEFF Research Database (Denmark)
Poel, Mike van der; Nielsen, C.V.; Rybaltover, M.;
2002-01-01
We measure angle differential cross sections (DCS) in Li+ + Na --> Li + Na+ electron transfer collisions in the 2.7-24 keV energy range. We do this with a newly constructed apparatus which combines the experimental technique of cold target recoil ion momentum spectroscopy with a laser-cooled target...... quantum scattering amplitudes are derived by the eikonal method. The resulting angle-differential electron transfer cross sections and their diffraction patterns agree with the experimental level-to-level results over most scattering angles in the energy range....
International Nuclear Information System (INIS)
The Synthetic Kernel (SKN) method is employed to a 3D absorbing, emitting and linearly anisotropically scattering inhomogeneous medium. Standard SKN approximation is applied only to the diffusive components of the radiative transfer equations. An alternative SKN (SKN⁎) method is also derived in full 3-D generality by extending the approximation to the direct wall contributions. Complete sets of boundary conditions for both SKN approaches are rigorously obtained. The simplified spherical harmonics (P2N−1 or SP2N−1) and simplified double spherical harmonics (DPN−1 or SDPN−1) equations for linearly anisotropically scattering homogeneous medium are also derived. Resulting full P2N−1 and DPN−1 (or SP2N−1 and SDPN−1) equations are cast as diagonalized second order coupled diffusion-like equations. By this analysis, it is shown that the SKN method is a high-order approximation, and simply by the selection of full or half range Gauss–Legendre quadratures, SKN⁎ equations become identical to P2N−1 or DPN−1 (or SP2N−1 or SDPN−1) equations. Numerical verification of all methods presented is carried out using a 1D participating isotropic slab medium. The SKN method proves to be more accurate than SKN⁎ approximation, but it is analytically more involved. It is shown that the SKN⁎ with proposed BCs converges with increasing order of approximation, and the BCs are applicable to SPN or SDPN methods. - Highlights: • SKN methods are extended to linear anisotropic scattering media. • Diagonalized simplified PN and simplified DPN equations are also derived. • PN and DPN quadratures are used with the SKN and SKN⁎ methods. • SKN methods are equivalent to SP2N−1 and SDPN−1 approximations
πHe and pHe elastic scattering at high energy and very low transfers
International Nuclear Information System (INIS)
Differential πHe and pHe cross sections for elastic scattering at incident momenta ranging from 100 to 300 GeV/c in the t range 0.0082 have been determined (NA8 experiment at CERN). Both particle recoil and forward scattered hadron were detected. The use of an active target allowing determination of the absolute normalization, the total hadron helium cross sections have been obtained from extrapolation of differential cross sections to the optical point. The results are compared with Glauber model calculation and the inelastic shadowing corrections deduced (from 1.5 to 3 mb in our energy range). The use of a quark parton model based on the notion of a hadron made of 2 or 3 clouds (constituant-quarks) of partons provides theoretical values of the corrections close to our experimental points
Scattering-angle based filtering of the waveform inversion gradients
Alkhalifah, Tariq Ali
2014-11-22
Full waveform inversion (FWI) requires a hierarchical approach to maneuver the complex non-linearity associated with the problem of velocity update. In anisotropic media, the non-linearity becomes far more complex with the potential trade-off between the multiparameter description of the model. A gradient filter helps us in accessing the parts of the gradient that are suitable to combat the potential non-linearity and parameter trade-off. The filter is based on representing the gradient in the time-lag normalized domain, in which the low scattering angle of the gradient update is initially muted out in the FWI implementation, in what we may refer to as a scattering angle continuation process. The result is a low wavelength update dominated by the transmission part of the update gradient. In this case, even 10 Hz data can produce vertically near-zero wavenumber updates suitable for a background correction of the model. Relaxing the filtering at a later stage in the FWI implementation allows for smaller scattering angles to contribute higher-resolution information to the model. The benefits of the extended domain based filtering of the gradient is not only it\\'s ability in providing low wavenumber gradients guided by the scattering angle, but also in its potential to provide gradients free of unphysical energy that may correspond to unrealistic scattering angles.
Energy Technology Data Exchange (ETDEWEB)
Kittl, J.A.; Testoni, J.E.; Macchiavelli, A.O.; Pacheco, A.J.; Abriola, D.; Gregorio, D.E. di; Etchegoyen, A.; Etchegoyen, M.C.; Fernandez Niello, J.O.; Ferrero, A.M.J.
1987-09-14
Recently measured scattering cross sections for the /sup 16/O+/sup 144/Sm system allow to extract a bare potential which is used in a global analysis of scattering, fusion and transfer experimental data for /sup 16/O on different samarium isotopes at energies close to the Coulomb barrier. The analysis is done within the framework of an extension of a method based on the intrinsic-coordinate-dependent phase shifts and the equivalent-spheres formalisms which has been previously reported. Consistent fits are obtained for an important amount of data covering a wide range of target deformations, bombarding energies and scattering angles for different reaction channels. As a significant exception, the fusion excitation function for /sup 144/Sm is overestimated.
Persistent Scatterer Interferometry based on geodetic estimation theory
Van Leijen, F.J.
2014-01-01
The Earth's surface is continuously deforming due to natural and anthropogenic processes, such as tectonics, landslides, oil and gas extraction, and groundwater level changes. Persistent Scatterer Interferometry is a technique that provides measurements of this surface motion based on satellite rada
Nonlinear stimulated Brillouin scattering based photonic signal processors
Energy Technology Data Exchange (ETDEWEB)
Minasian, Robert A. [School of Electrical and Information Engineering, Institute of Photonics and Optical Science, University of Sydney, NSW, Sydney, 2006 (Australia)
2014-10-06
Recent new methods in photonic signal processing based on stimulated Brillouin scattering, that enable the realization of photonic mixers with high conversion efficiency, ultra-wide continuously tunable high-resolution microwave photonic filters and programmable switchable microwave photonic tunable filters, are presented. These processors provide new capabilities for the realisation of high-performance and high-resolution signal processing.
Nonlinear stimulated Brillouin scattering based photonic signal processors
International Nuclear Information System (INIS)
Recent new methods in photonic signal processing based on stimulated Brillouin scattering, that enable the realization of photonic mixers with high conversion efficiency, ultra-wide continuously tunable high-resolution microwave photonic filters and programmable switchable microwave photonic tunable filters, are presented. These processors provide new capabilities for the realisation of high-performance and high-resolution signal processing
Thermal invisibility based on scattering cancellation and mantle cloaking.
Farhat, M; Chen, P-Y; Bagci, H; Amra, C; Guenneau, S; Alù, A
2015-01-01
We theoretically and numerically analyze thermal invisibility based on the concept of scattering cancellation and mantle cloaking. We show that a small object can be made completely invisible to heat diffusion waves, by tailoring the heat conductivity of the spherical shell enclosing the object. This means that the thermal scattering from the object is suppressed, and the heat flow outside the object and the cloak made of these spherical shells behaves as if the object is not present. Thermal invisibility may open new vistas in hiding hot spots in infrared thermography, military furtivity, and electronics heating reduction. PMID:25928664
Thermal invisibility based on scattering cancellation and mantle cloaking
Farhat, M.
2015-04-30
We theoretically and numerically analyze thermal invisibility based on the concept of scattering cancellation and mantle cloaking. We show that a small object can be made completely invisible to heat diffusion waves, by tailoring the heat conductivity of the spherical shell enclosing the object. This means that the thermal scattering from the object is suppressed, and the heat flow outside the object and the cloak made of these spherical shells behaves as if the object is not present. Thermal invisibility may open new vistas in hiding hot spots in infrared thermography, military furtivity, and electronics heating reduction.
Radiative transfer modeling of the enigmatic scattering polarization in the solar NaI D1 line
Belluzzi, Luca; Degl'Innocenti, Egidio Landi
2015-01-01
The modeling of the peculiar scattering polarization signals observed in some diagnostically important solar resonance lines requires the consideration of the detailed spectral structure of the incident radiation field as well as the possibility of ground level polarization, along with the atom's hyperfine structure and quantum interference between hyperfine F-levels pertaining either to the same fine structure J-level, or to different J-levels of the same term. Here we present a theoretical and numerical approach suitable for solving this complex non-LTE radiative transfer problem. This approach is based on the density-matrix metalevel theory (where each level is viewed as a continuous distribution of sublevels) and on accurate formal solvers of the transfer equations and efficient iterative methods. We show an application to the D-lines of NaI, with emphasis on the enigmatic D1 line, pointing out the observable signatures of the various physical mechanisms considered. We demonstrate that the linear polariza...
Personalized recommendation based on heat bidirectional transfer
Ma, Wenping; Feng, Xiang; Wang, Shanfeng; Gong, Maoguo
2016-02-01
Personalized recommendation has become an increasing popular research topic, which aims to find future likes and interests based on users' past preferences. Traditional recommendation algorithms pay more attention to forecast accuracy by calculating first-order relevance, while ignore the importance of diversity and novelty that provide comfortable experiences for customers. There are some levels of contradictions between these three metrics, so an algorithm based on bidirectional transfer is proposed in this paper to solve this dilemma. In this paper, we agree that an object that is associated with history records or has been purchased by similar users should be introduced to the specified user and recommendation approach based on heat bidirectional transfer is proposed. Compared with the state-of-the-art approaches based on bipartite network, experiments on two benchmark data sets, Movielens and Netflix, demonstrate that our algorithm has better performance on accuracy, diversity and novelty. Moreover, this method does better in exploiting long-tail commodities and cold-start problem.
A software-based x-ray scatter correction method for breast tomosynthesis
Jia Feng, Steve Si; Sechopoulos, Ioannis
2011-01-01
Purpose: To develop a software-based scatter correction method for digital breast tomosynthesis (DBT) imaging and investigate its impact on the image quality of tomosynthesis reconstructions of both phantoms and patients. Methods: A Monte Carlo (MC) simulation of x-ray scatter, with geometry matching that of the cranio-caudal (CC) view of a DBT clinical prototype, was developed using the Geant4 toolkit and used to generate maps of the scatter-to-primary ratio (SPR) of a number of homogeneous standard-shaped breasts of varying sizes. Dimension-matched SPR maps were then deformed and registered to DBT acquisition projections, allowing for the estimation of the primary x-ray signal acquired by the imaging system. Noise filtering of the estimated projections was then performed to reduce the impact of the quantum noise of the x-ray scatter. Three dimensional (3D) reconstruction was then performed using the maximum likelihood-expectation maximization (MLEM) method. This process was tested on acquisitions of a heterogeneous 50/50 adipose/glandular tomosynthesis phantom with embedded masses, fibers, and microcalcifications and on acquisitions of patients. The image quality of the reconstructions of the scatter-corrected and uncorrected projections was analyzed by studying the signal-difference-to-noise ratio (SDNR), the integral of the signal in each mass lesion (integrated mass signal, IMS), and the modulation transfer function (MTF). Results: The reconstructions of the scatter-corrected projections demonstrated superior image quality. The SDNR of masses embedded in a 5 cm thick tomosynthesis phantom improved 60%–66%, while the SDNR of the smallest mass in an 8 cm thick phantom improved by 59% (p < 0.01). The IMS of the masses in the 5 cm thick phantom also improved by 15%–29%, while the IMS of the masses in the 8 cm thick phantom improved by 26%–62% (p < 0.01). Some embedded microcalcifications in the tomosynthesis phantoms were visible only in the scatter
A software-based x-ray scatter correction method for breast tomosynthesis
Energy Technology Data Exchange (ETDEWEB)
Jia Feng, Steve Si; Sechopoulos, Ioannis [Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, and Department of Radiology and Imaging Sciences and Winship Cancer Institute, Emory University, 1701 Uppergate Drive Northeast, Suite 5018, Atlanta, Georgia 30322 (United States); Department of Radiology and Imaging Sciences, Hematology and Medical Oncology and Winship Cancer Institute, Emory University, 1701 Uppergate Drive Northeast, Suite 5018, Atlanta, Georgia 30322 (United States)
2011-12-15
Purpose: To develop a software-based scatter correction method for digital breast tomosynthesis (DBT) imaging and investigate its impact on the image quality of tomosynthesis reconstructions of both phantoms and patients. Methods: A Monte Carlo (MC) simulation of x-ray scatter, with geometry matching that of the cranio-caudal (CC) view of a DBT clinical prototype, was developed using the Geant4 toolkit and used to generate maps of the scatter-to-primary ratio (SPR) of a number of homogeneous standard-shaped breasts of varying sizes. Dimension-matched SPR maps were then deformed and registered to DBT acquisition projections, allowing for the estimation of the primary x-ray signal acquired by the imaging system. Noise filtering of the estimated projections was then performed to reduce the impact of the quantum noise of the x-ray scatter. Three dimensional (3D) reconstruction was then performed using the maximum likelihood-expectation maximization (MLEM) method. This process was tested on acquisitions of a heterogeneous 50/50 adipose/glandular tomosynthesis phantom with embedded masses, fibers, and microcalcifications and on acquisitions of patients. The image quality of the reconstructions of the scatter-corrected and uncorrected projections was analyzed by studying the signal-difference-to-noise ratio (SDNR), the integral of the signal in each mass lesion (integrated mass signal, IMS), and the modulation transfer function (MTF). Results: The reconstructions of the scatter-corrected projections demonstrated superior image quality. The SDNR of masses embedded in a 5 cm thick tomosynthesis phantom improved 60%-66%, while the SDNR of the smallest mass in an 8 cm thick phantom improved by 59% (p < 0.01). The IMS of the masses in the 5 cm thick phantom also improved by 15%-29%, while the IMS of the masses in the 8 cm thick phantom improved by 26%-62% (p < 0.01). Some embedded microcalcifications in the tomosynthesis phantoms were visible only in the scatter
A software-based x-ray scatter correction method for breast tomosynthesis
International Nuclear Information System (INIS)
Purpose: To develop a software-based scatter correction method for digital breast tomosynthesis (DBT) imaging and investigate its impact on the image quality of tomosynthesis reconstructions of both phantoms and patients. Methods: A Monte Carlo (MC) simulation of x-ray scatter, with geometry matching that of the cranio-caudal (CC) view of a DBT clinical prototype, was developed using the Geant4 toolkit and used to generate maps of the scatter-to-primary ratio (SPR) of a number of homogeneous standard-shaped breasts of varying sizes. Dimension-matched SPR maps were then deformed and registered to DBT acquisition projections, allowing for the estimation of the primary x-ray signal acquired by the imaging system. Noise filtering of the estimated projections was then performed to reduce the impact of the quantum noise of the x-ray scatter. Three dimensional (3D) reconstruction was then performed using the maximum likelihood-expectation maximization (MLEM) method. This process was tested on acquisitions of a heterogeneous 50/50 adipose/glandular tomosynthesis phantom with embedded masses, fibers, and microcalcifications and on acquisitions of patients. The image quality of the reconstructions of the scatter-corrected and uncorrected projections was analyzed by studying the signal-difference-to-noise ratio (SDNR), the integral of the signal in each mass lesion (integrated mass signal, IMS), and the modulation transfer function (MTF). Results: The reconstructions of the scatter-corrected projections demonstrated superior image quality. The SDNR of masses embedded in a 5 cm thick tomosynthesis phantom improved 60%-66%, while the SDNR of the smallest mass in an 8 cm thick phantom improved by 59% (p < 0.01). The IMS of the masses in the 5 cm thick phantom also improved by 15%-29%, while the IMS of the masses in the 8 cm thick phantom improved by 26%-62% (p < 0.01). Some embedded microcalcifications in the tomosynthesis phantoms were visible only in the scatter
Charge transfer and surface scattering at Cu-C60 planar interfaces
Hebard, A. F.; Ruel, R. R.; Eom, C. B.
1996-11-01
Thin-film planar structures of Cu and C60 have been sequentially deposited onto sapphire substrates in high vacuum and studied using in situ resistivity measurements during deposition together with ex situ atomic force microscopy characterization of surface topography. Two different regimes of behavior are identified. In the first of these, the thin-film limit in which the Cu is thin enough to be in the coalescence regime with an islanded morphology, the presence of an adjacent C60 monolayer, doped by charge transfer from the metal, creates a shunting path and a corresponding pronounced decrease in resistance. The sheet resistance of overlying doped monolayers is found to be ~8000 Ω, with a corresponding room-temperature resistivity that is a factor of 2 less than that of the three-dimensional alkali-metal-doped compounds A3C60 (A=K, Rb). The enhanced conductivity of an underlying monolayer of C60 is sufficient to reduce the critical thickness at which an overlying Cu film becomes conducting by almost a factor of 2 even though the roughness of such films is enhanced over that of Cu films deposited directly on the substrate. In the second regime of behavior, the continuous film limit in which the Cu is thick enough to have a size-effect resistivity proportional to the reciprocal of the film thickness, the presence of an adjacent C60 monolayer gives rise to an increase in resistance. Measurements on a number of samples with different thicknesses reveal that this resistance increase is best described by diffuse surface scattering. A scattering cross section of 5 AṦ resulting from a fit to this model represents the contact area under each C60 molecule.
Scattered Data Processing Approach Based on Optical Facial Motion Capture
Qiang Zhang; Xiaoying Liang; Xiaopeng Wei
2013-01-01
In recent years, animation reconstruction of facial expressions has become a popular research field in computer science and motion capture-based facial expression reconstruction is now emerging in this field. Based on the facial motion data obtained using a passive optical motion capture system, we propose a scattered data processing approach, which aims to solve the common problems of missing data and noise. To recover missing data, given the nonlinear relationships among neighbors with the ...
Model calculation of the charge transfer in low-energy He+ scattering from metallic surfaces
International Nuclear Information System (INIS)
Charge-transfer mechanisms in low-energy helium-scattering spectroscopy are analyzed by using an Anderson-like description of the time-dependent collisional process, which allows us to include several electronic bands of extended and localized nature in the solid. The Hamiltonian parameters are obtained from a Hartree-Fock self-consistent-field calculation of the He-target atom dimeric system. We examine in particular cases such as Ca and Ga linear chain substrates. We found that at velocities large enough, the localized state in the solid contributes to the He+ neutralization, showing the characteristic oscillatory behavior of the nonadiabatic charge exchange between localized states, in agreement with other calculations. In the range of low velocities we found that if the hybridization between the He orbital and the localized states in the solid is able to produce the formation of an antibonding state having a predominant weight of the He-1s orbital, this promotes the charge exchange between the Helium and the extended bandstates of the solid
Scattering angle base filtering of the inversion gradients
Alkhalifah, Tariq Ali
2014-01-01
Full waveform inversion (FWI) requires a hierarchical approach based on the availability of low frequencies to maneuver the complex nonlinearity associated with the problem of velocity inversion. I develop a model gradient filter to help us access the parts of the gradient more suitable to combat this potential nonlinearity. The filter is based on representing the gradient in the time-lag normalized domain, in which low scattering angles of the gradient update are initially muted. The result are long-wavelength updates controlled by the ray component of the wavefield. In this case, even 10 Hz data can produce near zero wavelength updates suitable for a background correction of the model. Allowing smaller scattering angle to contribute provides higher resolution information to the model.
International Nuclear Information System (INIS)
In this thesis, two studies of the diffractive phenomena in the electron proton collisions with the H1 detector at HERA are presented. The rst is the study of the inclusive elastic diffractive events ep → eXp in the regime of high photon virtuality (Q2>few GeV2), with the scattered proton detected by the Very Forward Proton Spectrometer (VFPS). The VFPS detector, designed to measure diffractive scattered protons with high acceptance, has been installed in 2004 to benefit from the HERA II luminosity increase. The selected event sample of an integrated luminosity of 130.2 pb-1 was collected in years 2006-2007. Data sample distributions are compared to the prediction based on the diffractive parton distribution functions, as extracted from the H1 measurement of the diffractive structure function FD(3)2 at HERA I. After the study of the VFPS efficiency, the VFPS acceptance as a function of xP is estimated and studied in relation to the forward proton beam optics. The second study leads to the cross section measurement of the diffractive scattering of quasi-real photons off protons, γp → γY, with the large momentum transfer, vertical stroke t vertical stroke. The final state photon is separated from the proton dissociation system, Y, by a large rapidity gap and has a large transverse momentum, pT > 2 GeV. Large pT imply the presence of the hard scale t (vertical stroke t vertical stroke ≅ p2T) and allows predictions of the perturbative QCD to be applied. The measurement is based on an integrated luminosity 46.2 pb-1 of data collected in the 1999-2000 running period. Cross sections σ(W) as a function of the incident photon-proton centre of mass energy, W, and dσ/d vertical stroke t vertical stroke are measured in the range Q22, 1752 and yP<0.05. The cross section measurements have been compared to predictions of LLA BFKL calculations. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Hreus, Tomas
2008-11-15
In this thesis, two studies of the diffractive phenomena in the electron proton collisions with the H1 detector at HERA are presented. The rst is the study of the inclusive elastic diffractive events ep {yields} eXp in the regime of high photon virtuality (Q{sup 2}>few GeV{sup 2}), with the scattered proton detected by the Very Forward Proton Spectrometer (VFPS). The VFPS detector, designed to measure diffractive scattered protons with high acceptance, has been installed in 2004 to benefit from the HERA II luminosity increase. The selected event sample of an integrated luminosity of 130.2 pb{sup -1} was collected in years 2006-2007. Data sample distributions are compared to the prediction based on the diffractive parton distribution functions, as extracted from the H1 measurement of the diffractive structure function F{sup D(3)}{sub 2} at HERA I. After the study of the VFPS efficiency, the VFPS acceptance as a function of x{sub P} is estimated and studied in relation to the forward proton beam optics. The second study leads to the cross section measurement of the diffractive scattering of quasi-real photons off protons, {gamma}p {yields} {gamma}Y, with the large momentum transfer, vertical stroke t vertical stroke. The final state photon is separated from the proton dissociation system, Y, by a large rapidity gap and has a large transverse momentum, p{sub T} > 2 GeV. Large p{sub T} imply the presence of the hard scale t (vertical stroke t vertical stroke {approx_equal} p{sup 2}{sub T}) and allows predictions of the perturbative QCD to be applied. The measurement is based on an integrated luminosity 46.2 pb{sup -1} of data collected in the 1999-2000 running period. Cross sections {sigma}(W) as a function of the incident photon-proton centre of mass energy, W, and d{sigma}/d vertical stroke t vertical stroke are measured in the range Q{sup 2}<0.01 GeV{sup 2}, 175
Design of a Compton scatter based radiation tracking system
Healy, Heather
Gamma spectroscopy is one of the most common techniques used for the detection of radiologic materials. This technology is deployed in a variety of scenarios such as emergency response, monitoring, and the recovery of lost, stolen, or otherwise unaccounted radiologic material. In most practical scenarios, it is useful to know the location of a source in relation to a detector, in addition to the classic output from gamma spectrometers such as decay rate and energy peak information. In collaboration with the Remote Sensing Laboratory (RSL) at Andrews Air Force Base, a novel detector design by RSL, which utilizes a 360° detectable range in order to increase the probability of remote detection, was investigated for the possibility to recreate source location information from Compton scattering events within the detector. A recreation of this novel detector is simulated using Geant4 to determine the optimal dimensions of sodium iodide detectors that produce the most single Compton scattering events in order to facilitate source location through the back-projection of Compton scattering angles. The optimal detector dimensions are determined by maximizing the number of single Compton scatter events and minimizing the percentage of Compton events that undergo multiple successive scatters in detectors of varying thicknesses and lengths. The optimal detector thickness was chosen to be 1.88 in, and the optimal detector length was chosen to be 4 to 4.5 in. In future projects, these optimized detectors can be used to apply suggested back-projection algorithms in order to determine the feasibility and functionality of this detector design for the purpose of radiologic source location.
Messina, Riccardo
2011-01-01
We study the radiative heat transfer and the Casimir-Lifshitz force occurring between two bodies in a system out of thermal equilibrium. We consider bodies of arbitrary shape and dielectric properties, held at two different temperatures, and immersed in a environmental radiation at a third different temperature. We derive explicit closed-form analytic expressions for the correlations of the electromagnetic field, and for the heat transfer and Casimir-Lifshitz force, in terms of the bodies scattering matrices. We then consider some particular cases which we investigate in detail: the atom-surface and the slab-slab configurations.
Energy Technology Data Exchange (ETDEWEB)
Messina, Riccardo [LNE-SYRTE, Observatoire de Paris, CNRS UMR 8630, UPMC, 61 avenue de l' Observatoire, F-75014 Paris (France); Antezza, Mauro [Universite Montpellier 2, Laboratoire Charles Coulomb UMR 5221, F-34095, Montpellier (France); CNRS, Laboratoire Charles Coulomb UMR 5221, F-34095, Montpellier (France)
2011-10-15
We study the radiative heat transfer and the Casimir-Lifshitz force occurring between two bodies in a system out of thermal equilibrium. We consider bodies of arbitrary shape and dielectric properties, held at two different temperatures and immersed in environmental radiation at a third different temperature. We derive explicit closed-form analytic expressions for the correlations of the electromagnetic field and for the heat transfer and Casimir-Lifshitz force in terms of the bodies' scattering matrices. We then consider some particular cases which we investigate in detail: the atom-surface and the slab-slab configurations.
International Nuclear Information System (INIS)
We study the radiative heat transfer and the Casimir-Lifshitz force occurring between two bodies in a system out of thermal equilibrium. We consider bodies of arbitrary shape and dielectric properties, held at two different temperatures and immersed in environmental radiation at a third different temperature. We derive explicit closed-form analytic expressions for the correlations of the electromagnetic field and for the heat transfer and Casimir-Lifshitz force in terms of the bodies' scattering matrices. We then consider some particular cases which we investigate in detail: the atom-surface and the slab-slab configurations.
Risk-based analytical method transfer: application to large multi-product transfers.
Raska, Christina S; Bennett, Tony S; Goodberlet, Scott A
2010-07-15
As pharmaceutical companies adapt their business models, a new approach to analytical method transfer is needed to efficiently handle transfers of multiple products, associated with situations such as site consolidations/closures. Using the principles of risk management, a risk-based method transfer approach is described, which defines appropriate transfer activities based on a risk assessment of the methods and experience of the receiving unit. A key step in the process is detailed knowledge transfer from the transferring unit to the receiving unit. The amount of transfer testing required can be streamlined or eliminated on the basis of a number of factors, including method capability, receiving unit familiarity, and method past performance. PMID:20557030
Light scattering in opal-based photonic crystals
Limonov, M. F.
2010-05-01
We present a new light scattering pattern in low-contrast opal-based photonic crystals (PhCs). The structure of real opals is always imperfect because of the a-SiO2 particles being inherently inhomogeneous and nonuniform in size and average dielectric permittivity. We found that opals possess all predictable properties of multi-component PhCs, which we define as periodic structures consisting of inhomogeneous or multiple (three or more) components. By theory, by properly tuning the permittivity of one of the components in ordered, low-contrast multi-component PhCs (for instance, of the filler ɛf in an opal), one can produce selective disappearance of any non-resonant (hkl) stop band. A study of transmission spectra of opals revealed that stop bands exhibit different (including resonant) behavior under variation of ɛf. Experiment did not, however, substantiate complete disappearance of stop bands predicted by theory for an ordered PhC. In the region of the predicted disappearance, a new effect has been observed, namely flip-over of the Bragg band, i.e., transformation of the Bragg dip into a Bragg rise. The flip-over effect, which has been studied in considerable detail in the particular example of the (111) stop band, originates from the nonuniformity of a-SiO2 particles. This nonuniformity leads to additional broad-band light scattering, the character of which is determined by Mie scattering. Thus, Mie scattering is responsible for two components in opal transmission spectra, more specifically, narrow Bragg bands and broad-band background. Their interference gives rise to formation of the Fano resonance, which in opal spectra becomes manifest, first, in a Bragg band asymmetry, and, second, in the flip-over effect, i.e., transformation of a photonic stop band into a photonic pass band.
Event-based processing of neutron scattering data
Peterson, Peter F.; Campbell, Stuart I.; Reuter, Michael A.; Taylor, Russell J.; Zikovsky, Janik
2015-12-01
Many of the world's time-of-flight spallation neutrons sources are migrating to recording individual neutron events. This provides for new opportunities in data processing, the least of which is to filter the events based on correlating them with logs of sample environment and other ancillary equipment. This paper will describe techniques for processing neutron scattering data acquired in event mode which preserve event information all the way to a final spectrum, including any necessary corrections or normalizations. This results in smaller final uncertainties compared to traditional methods, while significantly reducing processing time and memory requirements in typical experiments. Results with traditional histogramming techniques will be shown for comparison.
Hermite interpolation of scattered data based on the assistant surface
Institute of Scientific and Technical Information of China (English)
WANG Quan-wei; LI Xue-yi; LI Bin; WANG Xiao-chun
2006-01-01
An assistant surface was constructed on the base of boundary that being automatically extracted from the scattered data. The parameters of every data point corresponding to the assistant surface and their applied fields were calculated respectively. In every applied region, a surface patch was constructed by a special Hermite interpolation.The final surface can be obtained by a piecewise bicubic Hermite interpolation in the aggregate of applied regions of metrical data. This method avoids the triangulation problem.Numerical results indicate that it is efficient and accurate.
International Nuclear Information System (INIS)
To solve the 3D-VRT equation for the model of spatially inhomogeneous scatter media, the finite enclosure of the scatter media is geometrically divided, in both vertical z and transversal (x,y) directions, to form very thin multi-boxes. The zeroth order emission, first-order Mueller matrix of each thin box and an iterative approach of high-order radiative transfer are applied to derive high-order scattering and emission of whole inhomogeneous scatter media. Numerical results of polarized brightness temperature at microwave frequency and under different radiometer resolutions from inhomogeneous scatter model such as vegetation canopy and alien target beneath canopy are simulated and discussed
Xiang, Deliang; Tang, Tao; Ban, Yifang; Su, Yi; Kuang, Gangyao
2016-06-01
Since it has been validated that cross-polarized scattering (HV) is caused not only by vegetation but also by rotated dihedrals, in this study, we use rotated dihedral corner reflectors to form a cross scattering matrix and propose an extended four-component model-based decomposition method for PolSAR data over urban areas. Unlike other urban area decomposition techniques which need to discriminate the urban and natural areas before decomposition, this proposed method is applied on PolSAR image directly. The building orientation angle is considered in this scattering matrix, making it flexible and adaptive in the decomposition. Therefore, we can separate cross scattering of urban areas from the overall HV component. Further, the cross and helix scattering components are also compared. Then, using these decomposed scattering powers, the buildings and natural areas can be easily discriminated from each other using a simple unsupervised K-means classifier. Moreover, buildings aligned and not aligned along the radar flight direction can be also distinguished clearly. Spaceborne RADARSAT-2 and airborne AIRSAR full polarimetric SAR data are used to validate the performance of our proposed method. The cross scattering power of oriented buildings is generated, leading to a better decomposition result for urban areas with respect to other state-of-the-art urban decomposition techniques. The decomposed scattering powers significantly improve the classification accuracy for urban areas.
Scattered Data Processing Approach Based on Optical Facial Motion Capture
Directory of Open Access Journals (Sweden)
Qiang Zhang
2013-01-01
Full Text Available In recent years, animation reconstruction of facial expressions has become a popular research field in computer science and motion capture-based facial expression reconstruction is now emerging in this field. Based on the facial motion data obtained using a passive optical motion capture system, we propose a scattered data processing approach, which aims to solve the common problems of missing data and noise. To recover missing data, given the nonlinear relationships among neighbors with the current missing marker, we propose an improved version of a previous method, where we use the motion of three muscles rather than one to recover the missing data. To reduce the noise, we initially apply preprocessing to eliminate impulsive noise, before our proposed three-order quasi-uniform B-spline-based fitting method is used to reduce the remaining noise. Our experiments showed that the principles that underlie this method are simple and straightforward, and it delivered acceptable precision during reconstruction.
International Nuclear Information System (INIS)
We have experimentally and theoretically investigated the light-matter interaction in metallic nano-hole array structures. The scattering cross section spectrum was measured for three samples each having a unique nano-hole array radius and periodicity. Each measured spectrum had several peaks due to surface plasmon polaritons. The dispersion relation and the effective dielectric constant of the structure were calculated using transmission line theory and Bloch's theorem. Using the effective dielectric constant and the transfer matrix method, the surface plasmon polariton energies were calculated and found to be quantized. Using these quantized energies, a Hamiltonian for the surface plasmon polaritons was written in the second quantized form. Working with the Hamiltonian, a theory of scattering cross section was developed based on the quantum scattering theory and Green's function method. For both theory and experiment, the location of the surface plasmon polariton spectral peaks was dependant on the array periodicity and radii of the nano-holes. Good agreement was observed between the experimental and theoretical results. It is proposed that the newly developed theory can be used to facilitate optimization of nanosensors for medical and engineering applications
Ultrafast image-based dynamic light scattering for nanoparticle sizing
Zhou, Wu; Zhang, Jie; Liu, Lili; Cai, Xiaoshu
2015-11-01
An ultrafast sizing method for nanoparticles is proposed, called as UIDLS (Ultrafast Image-based Dynamic Light Scattering). This method makes use of the intensity fluctuation of scattered light from nanoparticles in Brownian motion, which is similar to the conventional DLS method. The difference in the experimental system is that the scattered light by nanoparticles is received by an image sensor instead of a photomultiplier tube. A novel data processing algorithm is proposed to directly get correlation coefficient between two images at a certain time interval (from microseconds to milliseconds) by employing a two-dimensional image correlation algorithm. This coefficient has been proved to be a monotonic function of the particle diameter. Samples of standard latex particles (79/100/352/482/948 nm) were measured for validation of the proposed method. The measurement accuracy of higher than 90% was found with standard deviations less than 3%. A sample of nanosilver particle with nominal size of 20 ± 2 nm and a sample of polymethyl methacrylate emulsion with unknown size were also tested using UIDLS method. The measured results were 23.2 ± 3.0 nm and 246.1 ± 6.3 nm, respectively, which is substantially consistent with the transmission electron microscope results. Since the time for acquisition of two successive images has been reduced to less than 1 ms and the data processing time in about 10 ms, the total measuring time can be dramatically reduced from hundreds seconds to tens of milliseconds, which provides the potential for real-time and in situ nanoparticle sizing.
Ultrafast image-based dynamic light scattering for nanoparticle sizing
Energy Technology Data Exchange (ETDEWEB)
Zhou, Wu; Zhang, Jie; Liu, Lili; Cai, Xiaoshu, E-mail: usst-caixs@163.com [Institute of Particle and Two-Phase Flow Measurement, Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093 (China)
2015-11-15
An ultrafast sizing method for nanoparticles is proposed, called as UIDLS (Ultrafast Image-based Dynamic Light Scattering). This method makes use of the intensity fluctuation of scattered light from nanoparticles in Brownian motion, which is similar to the conventional DLS method. The difference in the experimental system is that the scattered light by nanoparticles is received by an image sensor instead of a photomultiplier tube. A novel data processing algorithm is proposed to directly get correlation coefficient between two images at a certain time interval (from microseconds to milliseconds) by employing a two-dimensional image correlation algorithm. This coefficient has been proved to be a monotonic function of the particle diameter. Samples of standard latex particles (79/100/352/482/948 nm) were measured for validation of the proposed method. The measurement accuracy of higher than 90% was found with standard deviations less than 3%. A sample of nanosilver particle with nominal size of 20 ± 2 nm and a sample of polymethyl methacrylate emulsion with unknown size were also tested using UIDLS method. The measured results were 23.2 ± 3.0 nm and 246.1 ± 6.3 nm, respectively, which is substantially consistent with the transmission electron microscope results. Since the time for acquisition of two successive images has been reduced to less than 1 ms and the data processing time in about 10 ms, the total measuring time can be dramatically reduced from hundreds seconds to tens of milliseconds, which provides the potential for real-time and in situ nanoparticle sizing.
Ultrafast image-based dynamic light scattering for nanoparticle sizing
International Nuclear Information System (INIS)
An ultrafast sizing method for nanoparticles is proposed, called as UIDLS (Ultrafast Image-based Dynamic Light Scattering). This method makes use of the intensity fluctuation of scattered light from nanoparticles in Brownian motion, which is similar to the conventional DLS method. The difference in the experimental system is that the scattered light by nanoparticles is received by an image sensor instead of a photomultiplier tube. A novel data processing algorithm is proposed to directly get correlation coefficient between two images at a certain time interval (from microseconds to milliseconds) by employing a two-dimensional image correlation algorithm. This coefficient has been proved to be a monotonic function of the particle diameter. Samples of standard latex particles (79/100/352/482/948 nm) were measured for validation of the proposed method. The measurement accuracy of higher than 90% was found with standard deviations less than 3%. A sample of nanosilver particle with nominal size of 20 ± 2 nm and a sample of polymethyl methacrylate emulsion with unknown size were also tested using UIDLS method. The measured results were 23.2 ± 3.0 nm and 246.1 ± 6.3 nm, respectively, which is substantially consistent with the transmission electron microscope results. Since the time for acquisition of two successive images has been reduced to less than 1 ms and the data processing time in about 10 ms, the total measuring time can be dramatically reduced from hundreds seconds to tens of milliseconds, which provides the potential for real-time and in situ nanoparticle sizing
Scattering assisted injection based injectorless mid infrared quantum cascade laser
International Nuclear Information System (INIS)
An injectorless five-well mid infrared quantum cascade laser is analyzed which relies on phonon scattering injection in contrast to resonant tunneling injection, which has been previously used for injectorless designs. A Monte Carlo based self-consistent electron and photon transport simulator is used to analyze the performance of the analyzed design and compare it to existing injectorless designs. The simulation results show that the analyzed design could greatly enhance the optical gain and the characteristic temperatures of injectorless quantum cascade lasers (QCLs) which have typically been hindered by low characteristic temperatures and significant temperature related performance degradation. Simulations of the analyzed device predict threshold current densities of 0.85 kA/cm2 and 1.95 kA/cm2 at 77 K and 300 K, respectively, which are comparable to the threshold current densities of conventional injector based QCLs.
Scattering assisted injection based injectorless mid infrared quantum cascade laser
Energy Technology Data Exchange (ETDEWEB)
Singh, Siddharth, E-mail: thakursiddarth.singh@stonybrook.edu; Kamoua, Ridha [Department of Electrical and Computer Engineering, Stony Brook University, Stony Brook, New York 11794 (United States)
2014-06-07
An injectorless five-well mid infrared quantum cascade laser is analyzed which relies on phonon scattering injection in contrast to resonant tunneling injection, which has been previously used for injectorless designs. A Monte Carlo based self-consistent electron and photon transport simulator is used to analyze the performance of the analyzed design and compare it to existing injectorless designs. The simulation results show that the analyzed design could greatly enhance the optical gain and the characteristic temperatures of injectorless quantum cascade lasers (QCLs) which have typically been hindered by low characteristic temperatures and significant temperature related performance degradation. Simulations of the analyzed device predict threshold current densities of 0.85 kA/cm{sup 2} and 1.95 kA/cm{sup 2} at 77 K and 300 K, respectively, which are comparable to the threshold current densities of conventional injector based QCLs.
Penning transfer in argon-based gas mixtures
Sahin, O; Tapan, I; Ozmutlu, E N
2010-01-01
Penning transfers, a group of processes by which excitation energy is used to ionise the gas, increase the gas gain in some detectors. Both the probability that such transfers occur and the mechanism by which the transfer takes place, vary with the gas composition and pressure. With a view to developing a microscopic electron transport model that takes Penning transfers into account, we use this dependence to identify the transfer mechanisms at play. We do this for a number of argon-based gas mixtures, using gain curves from the literature.
Energy Technology Data Exchange (ETDEWEB)
Moore, Stephen C. [Department of Radiology, Brigham and Women' s Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115 (United States)]. E-mail: scmoore@bwh.harvard.edu; Ouyang, Jinsong [Department of Radiology, Brigham and Women' s Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115 (United States); Park, Mi-Ae [Department of Radiology, Brigham and Women' s Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115 (United States); El Fakhri, Georges [Department of Radiology, Brigham and Women' s Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115 (United States)
2006-12-20
We have incorporated Monte Carlo (MC)-based estimates of patient scatter, detector scatter, and crosstalk into an iterative reconstruction algorithm, and compared its performance to that of a general spectral (GS) approach. We extended the MC-based reconstruction algorithm of de Jong et al. by (1) using the 'Delta scattering' method to determine photon interaction points (2) simulating scatter maps for many energy bins simultaneously, and (3) decoupling the simulation of the object and detector by using pre-stored point spread functions (PSF) that included all collimator and detector effects. A numerical phantom was derived from a segmented CT scan of a torso phantom. The relative values of In-111 activity concentration simulated in soft tissue, liver, spine, left lung, right lung, and five spherical tumors (1.3-2.0 cm diam.) were 1.0, 1.5, 1.5, 0.3, 0.5, and 10.0, respectively. GS scatter projections were incorporated additively in an OSEM reconstruction (6 subsetsx10 projectionsx2 photopeak windows). After three iterations, GS scatter projections were replaced by MC-estimated scatter projections for two additional iterations. MC-based compensation was quantitatively compared to GS-based compensation after five iterations. The bias of organ activity estimates ranged from -13% to -6.5% (GS), and from -1.4% to +5.0% (MC); tumor bias ranged from -20.0% to +10.0% for GS (mean{+-}std.dev.=-4.3{+-}11.9%), and from -2.2 to +18.8% for MC (+4.1{+-}8.6%). Image noise in all organs was less with MC than with GS.
Evaluation of Influence of Multiple Scattering Effect in Light-Scattering-Based Applications
Institute of Scientific and Technical Information of China (English)
XU Sheng-Hua; SUN Zhi-Wei
2007-01-01
The extinction cross sections of a system containing two particles are calculated by the T-matrix method, and the results are compared with those of two single particles with single-scattering approximation. The necessity of the correction of the refractive indices of water and polystyrene for different incident wavelengths is particularly addressed in the calculation. By this means, the volume fractions allowed for certain accuracy requirements of single-scattering approximation in the light scattering experiment can be evaluated. The volume fractions calculated with corrected refractive indices are compared with those obtained with fixed refractive indices which have been rather commonly used, showing that fixed refractive indices may cause significant error in evaluating multiple scattering effect. The results also give a simple criterion for selecting the incident wavelength and particle size to avoid the 'blind zone' in the turbidity measurement, where the turbidity change is insensitive to aggregation of two particles.
A passive FPAA based RF scatter meteor detector
Popowicz, Adam; Bernacki, Krzysztof; Fietkiewicz, Karol
2015-01-01
In the article we present a hardware meteor detector. The detection principle is based on the electromagnetic wave reflection from the ionized meteor trail in the atmosphere. The detector uses the ANADIGM field programmable analogue array (FPAA), which is an attractive alternative for a typically used detecting equipment - a PC computer with dedicated software. We implement an analog signal path using most of available FPAA resources to obtain precise audio signal detection. Our new detector was verified in collaboration with the Polish Fireball Network - the organization which monitors meteor activity in Poland. When compared with currently used signal processing PC software employing real radio meteor scatter signals, our low-cost detector proved to be more precise and reliable. Due to its cost and efficiency superiority over the current solution, the presented module is going to be implemented in the planned distributed detectors system.
Back-scatter based whispering gallery mode sensing
Knittel, Joachim; McAuslan, David L; Brawley, George A; Bowen, Warwick P
2013-01-01
Whispering gallery mode biosensors allow selective unlabelled detection of single proteins and, combined with quantum limited sensitivity, the possibility for noninvasive realtime observation of motor molecule motion. However, to date technical noise sources, most particularly low frequency laser noise, have constrained such applications. Here we introduce a new technique for whispering gallery mode sensing based on direct detection of back-scattered light. This experimentally straightforward technique is immune to frequency noise in principle, and further, acts to suppress thermorefractive noise. We demonstrate 27 dB of frequency noise suppression, eliminating frequency noise as a source of sensitivity degradation and allowing an absolute frequency shift sensitivity of 76 kHz. Our results open a new pathway towards single molecule biophysics experiments and ultrasensitive biosensors.
Database for rapid protein classification based on small-angle X-ray scattering data
International Nuclear Information System (INIS)
A method was developed for rapid protein classification based on comparison of the experimental small-angle X-ray scattering data with scattering curves calculated for proteins with known structures. For this purpose, a database was compiled from about 1500 theoretical scattering curves for proteins with known structures. The potential of this method was illustrated by its application to analysis of the experimental scattering data from sperm whale myoglobin
Meziane, M; Jones, M K; Luo, W; Pentchev, L; Perdrisat, C F; Puckett, A J R; Punjabi, V; Wesselmann, F R; Ahmidouch, A; Albayrak, I; Aniol, K A; Arrington, J; Asaturyan, A; Ates, O; Baghdasaryan, H; Benmokhtar, F; Bertozzi, W; Bimbot, L; Bosted, P; Boeglin, W; Butuceanu, C; Carter, P; Chernenko, S; Christy, E; Commisso, M; Cornejo, J C; Covrig, S; Danagoulian, S; Daniel, A; Davidenko, A; Day, D; Dhamija, S; Dutta, D; Ent, R; Frullani, S; Fenker, H; Frlez, E; Garibaldi, F; Gaskell, D; Gilad, S; Gilman, R; Goncharenko, Y; Hafidi, K; Hamilton, D; Higinbotham, D W; Hinton, W; Horn, T; Hu, B; Huang, J; Huber, G M; Jensen, E; Kang, H; Keppel, C; Khandaker, M; King, P; Kirillov, D; Kohl, M; Kravtsov, V; Kumbartzki, G; Li, Y; Mamyan, V; Margaziotis, D J; Markowitz, P; Marsh, A; Matulenko, Y; Maxwell, J; Mbianda, G; Meekins, D; Melnik, Y; Miller, J; Mkrtchyan, A; Mkrtchyan, H; Moffit, B; Moreno, O; Mulholland, J; Narayan, A; Nuruzzaman,; Nedev, S; Piasetzky, E; Pierce, W; Piskunov, N M; Prok, Y; Ransome, R D; Razin, D S; Reimer, P E; Reinhold, J; Rondon, O; Shabestari, M; Shahinyan, A; Shestermanov, K; Sirca, S; Sitnik, I; Smykov, L; Smith, G; Solovyev, L; Solvignon, P; Subedi, R; Suleiman, R; Tomasi-Gustafsson, E; Vasiliev, A; Vanderhaeghen, M; Veilleux, M; Wojtsekhowski, B B; Wood, S; Ye, Z; Zanevsky, Y; Zhang, X; Zhang, Y; Zheng, X; Zhu, L
2010-01-01
Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton form factor ratio $G_{Ep}/G_{Mp}$ obtained from cross section and polarization measurements. One possible explanation for this difference is a two-photon-exchange contribution. We report the results of the JLab Hall C $GEp2\\gamma$ experiment, which measured the kinematical dependence of polarization transfer observables in elastic electron-proton scattering at $Q^2=2.5$ GeV$^2$, in search of effects beyond the Born approximation. For a wide range of values of the kinematic factor $\\epsilon$ ($\\epsilon=$0.15, 0.63, and 0.77), the proton polarization component ratio and the longitudinal polarization transfer component were measured with statistical uncertainties of $\\pm$0.01 and $\\pm$0.006 and systematic uncertainties of 0.013 and 0.01, respectively.
Lexical transfer in Norwegian interlanguage : A detection-based approach
2012-01-01
This study investigates cross-linguistic influence ('transfer') in Norwegian interlanguage using predictive data mining technology and with a focus on lexical transfer. The impetus for the present work came from the publication of a series of studies (Jarvis & Crossley 2012) that explore the 'detection-based approach' to language transfer. The following research questions are addressed: 1. Can data mining techniques be used to identify the L1 background of Norwegian language learners ...
Orbit Clustering Based on Transfer Cost
Gustafson, Eric D.; Arrieta-Camacho, Juan J.; Petropoulos, Anastassios E.
2013-01-01
We propose using cluster analysis to perform quick screening for combinatorial global optimization problems. The key missing component currently preventing cluster analysis from use in this context is the lack of a useable metric function that defines the cost to transfer between two orbits. We study several proposed metrics and clustering algorithms, including k-means and the expectation maximization algorithm. We also show that proven heuristic methods such as the Q-law can be modified to work with cluster analysis.
Antiproton small momentum transfer charge exchange scattering on protons at 30 GeV/c
International Nuclear Information System (INIS)
Antiproton charge exchange scattering on protons anti pp→anti nn is investigated with 30 GeV/c antiprotons at the IHEP accelerator. The experiment confirms the existence of a structure at small angles in the angular distribution of this reaction at high energies, observed earlier
Neutron scattering from liquid {sup 3}He at large momentum transfers
Energy Technology Data Exchange (ETDEWEB)
Azuah, R.T. [Keele Univ. (United Kingdom). Dept. of Physics]|[Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Stirling, W.G. [Keele Univ. (United Kingdom). Dept. of Physics; Guckelsberger, K. [Physikalisch-Technische Bundesanstalt, Bundesallee 100, Postfach 3345, 38116 Braunschweig (Germany); Scherm, R. [Physikalisch-Technische Bundesanstalt, Bundesallee 100, Postfach 3345, 38116 Braunschweig (Germany)]|[Institut Laue-Langevin, BP 156X, F-38042 Grenoble (France); Glyde, H.R. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Bennington, S.M. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX (United Kingdom); Taylor, A.D. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX (United Kingdom)
1995-08-01
Neutron inelastic scattering measurements have been made on liquid {sup 3}He at 1.4 K for wave vectors between 9 and 20 A{sup -1}. The peak positions and widths are extracted and the mean kinetic energy determined. A new (theoretical) moment technique is used to investigate the momentum distribution and final-state effects. (orig.).
Heat transfer in cellulose-based aerogels: Analytical modelling and measurements
International Nuclear Information System (INIS)
A simple analytical approach for estimating the total heat transfer inside new cellulose-based aerogels has been investigated. The model accounts for the characteristic solid matrix at the nanometric scale by using a cellular representation of the nanofoam porous structure. The radiation-conduction heat transfer is taken into account. Previous analytical correlation for the fluid phase is used to model the conduction heat transfer in gas. New analytical formulations based on mean free path theory combined with phonon tracking approach are proposed to model the conduction heat transfer in the solid phase at the nanometric scale. The contribution of radiation heat transfer is obtained from Rayleigh scattering approach combined to the Rosseland approximation. These analytical relations validated experimentally are expected to be useful for researchers aiming at developing new insulating organic aerogels since they permit to determine conduction-radiation equivalent conductivity as a function of cell dimensions, phonon and optical properties of cellulose. - Highlights: • Development of an original model for estimating the heat transfer in aerocellulose. • Radiation, fluid conduction and solid conduction contributions are treated separately. • Modelling takes into account the “nanoscopic effects”. • Results validated experimentally under different temperature and pressure
Institute of Scientific and Technical Information of China (English)
ZHONG Jin-rong; WEN Gong-jian; HUI Bing-wei; LI De-ren
2015-01-01
A method and procedure is presented to reconstruct three-dimensional (3D) positions of scattering centers from multiple synthetic aperture radar (SAR) images. Firstly, two-dimensional (2D) attribute scattering centers of targets are extracted from 2D SAR images. Secondly, similarity measure is developed based on 2D attributed scatter centers' location, type, and radargrammetry principle between multiple SAR images. By this similarity, we can associate 2D scatter centers and then obtain candidate 3D scattering centers. Thirdly, these candidate scattering centers are clustered in 3D space to reconstruct final 3D positions. Compared with presented methods, the proposed method has a capability of describing distributed scattering center, reduces false and missing 3D scattering centers, and has fewer restrictionson modeling data. Finally, results of experiments have demonstrated the effectiveness of the proposed method.
Spin transfer to Λ and hyperons in deep inelastic scattering at HERMES
Belostotski, S. L.
2014-01-01
Preliminary results on the spin transfer to the Λ and hyperons measured by the HERMES Collaboration are presented. Longitudinal spin transfer directed along the virtual-photon momentum in the Λ rest frame is found to be D {/LL Λ} = 0.19 ± 0.04stat ± 0.02syst, the transverse component being compatible with zero. For both longitudinal and transverse components are compatible with zero within statistical errors of ±0.1.
Bioanalytical method transfer considerations of chromatographic-based assays.
Williard, Clark V
2016-07-01
Bioanalysis is an important part of the modern drug development process. The business practice of outsourcing and transferring bioanalytical methods from laboratory to laboratory has increasingly become a crucial strategy for successful and efficient delivery of therapies to the market. This chapter discusses important considerations when transferring various types of chromatographic-based assays in today's pharmaceutical research and development environment. PMID:27277876
High Throughput WAN Data Transfer with Hadoop-based Storage
International Nuclear Information System (INIS)
Hadoop distributed file system (HDFS) is becoming more popular in recent years as a key building block of integrated grid storage solution in the field of scientific computing. Wide Area Network (WAN) data transfer is one of the important data operations for large high energy physics experiments to manage, share and process datasets of PetaBytes scale in a highly distributed grid computing environment. In this paper, we present the experience of high throughput WAN data transfer with HDFS-based Storage Element. Two protocols, GridFTP and fast data transfer (FDT), are used to characterize the network performance of WAN data transfer.
Coronene-based charge-transfer complexes.
Yoshida, Yukihiro; Isomura, Kazuhide; Kumagai, Yoshihide; Maesato, Mitsuhiko; Kishida, Hideo; Mizuno, Motohiro; Saito, Gunzi
2016-08-01
Recent developments in the arena of charge-transfer complexes composed of the D 6h-symmetric polycyclic aromatic hydrocarbon, coronene, are highlighted with emphasis on the structural and physical properties of these complexes. Because of the dual electron-donating and -accepting abilities of coronene, this group involves structurally-defined four cation salts and three anion salts. The Jahn-Teller distortions and in-plane motion of coronene molecules in the solids, both of which are closely associated with the high symmetry of coronene molecules, and syntheses of clathrate-type complexes are also presented. PMID:27294380
Toward a new radiative-transfer-based model for remote sensing of terrestrial surface albedo.
Cui, Shengcheng; Zhen, Xiaobing; Wang, Zhen; Yang, Shizhi; Zhu, WenYue; Li, Xuebin; Huang, Honghua; Wei, Heli
2015-08-15
This Letter formulates a simple yet accurate radiative-transfer-based theoretical model to characterize the fraction of radiation reflected by terrestrial surfaces. Emphasis is placed on the concept of inhomogeneous distribution of the diffuse sky radiation function (DSRF) and multiple interaction effects (MIE). Neglecting DSRF and MIE produces a -1.55% mean relative bias in albedo estimates. The presented model can elucidate the impact of DSRF on the surface volume scattering and geometry-optical scattering components, respectively, especially for slant illuminations with solar zenith angles (SZA) larger than 50°. Particularly striking in the comparisons between our model and ground-based observations is the achievement of the agreement level, indicating that our model can effectively resolve the longstanding issue in accurately estimating albedo at extremely large SZAs and is promising for land-atmosphere interactions studies. PMID:26274674
Inelastic scattering and nucleon transfer in the system 232Th+206Pb at the Coulomb barrier
International Nuclear Information System (INIS)
By the experiment performed in the present thesis on the example of the system 232Th+206Pb the onset of the nuclear interaction in the region of the Coulomb barrier was studied at an incident energy of 6.3 MeV/nucleon. In the range of distances of closest approximation 15.5 fm ≤ D ≤ 38.7 fm respectively 28deg ≤ ΘCM ≤ 150deg the Coulomb excitation of the target isotope was observed. The strong absorption for 'small' distances from the reaction channel of the Coulomb excitation is confirmed by the occurrence of transfer reactions. In the studied thorium-lead system the transfer of one and two neutrons could be detected by means of the characteristic γ radiation of the isotopes 230Th and 207,208Pb with a cross section of 500 mb summed over the measurement range. The possibilities of an evaporation of neutrons from highly excited target nuclei, which could also lead to the isotope 230Th and by this influence the measurement of the 2n transfer, was also studied. The contribution of these processes to the transfer could be estimated to less than 5%. For the determination of the excitation energy, at which the transfer takes place, the transfer probabilities experimentally determined as functions of the distance of closest approximation were compared with the barrier-penetration model originally developed for sub-Coulomb transfer. Small effective neutron-binding energies of 0.6-0.8 MeV and by this high excitation energies resulted in contradiction to our model-independent measurement by means of the mean γ multiplicity and mean γ energies. (orig./HSI)
International Nuclear Information System (INIS)
The importance of accounting for resonance self-screening effects in multigroup cross sections when calculating fast reactors and neutron shields is considered. Formulae for averaging cross sections over resonance features with the account of anisotropy for scattering with large energy losses are derived. The model calculations of neutron fluxes have been performed for a U-H mixture (rhosub(H)/rhosub(U)=0.1), a U-Fe-H mixture and for the latter with rhosub(5)/rhosub(Fe)=0.01-0.5. It is concluded that in hydrogen-containing reactors the effect may be significant if the core contains iron in large quantities. The cross section averaging is considered for 3 systems: the KBR-2 critical assembly, spherical model of a large breeder, critical sphere of UO2 with 30% enrichment. The scattering anisotropy changes the multiplication factors of the first two systems by about 0.3%
Sasse, Christian
1993-12-01
Measured optical properties of large absorbing arbitrarily shaped particulates are compared to calculated optical properties of smooth homogeneous spheres. The particulates examined are spherical carbon particles with rough surface structure and oil shale. The results of measurements of phase functions of single particles at (lambda) equals 514.5 nm and hemispherical reflectance from 450 to 1959 nm are used in an inverse two-flux model to calculate the average albedo of a single particle. For carbon particles, ideal spheres show a higher forward scatter contribution than measured properties of rough spheres. Two types of oil shale particles with different optical properties but similar size and surface structure are investigated. Particle albedo and phase functions are compared, and the error of measuring the phase function at one wavelength is investigated. Results are also compared to isotropic scattering particles.
Soil-Carbon Measurement System Based on Inelastic Neutron Scattering
International Nuclear Information System (INIS)
Increase in the atmospheric CO2 is associated with concurrent increase in the amount of carbon sequestered in the soil. For better understanding of the carbon cycle it is imperative to establish a better and extensive database of the carbon concentrations in various soil types, in order to develop improved models for changes in the global climate. Non-invasive soil carbon measurement is based on Inelastic Neutron Scattering (INS). This method has been used successfully to measure total body carbon in human beings. The system consists of a pulsed neutron generator that is based on D-T reaction, which produces 14 MeV neutrons, a neutron flux monitoring detector and a couple of large NaI(Tl), 6'' diameter by 6'' high, spectrometers [4]. The threshold energy for INS reaction in carbon is 4.8 MeV. Following INS of 14 MeV neutrons in carbon 4.44 MeV photons are emitted and counted during a gate pulse period of 10 μsec. The repetition rate of the neutron generator is 104 pulses per sec. The gamma spectra are acquired only during the neutron generator gate pulses. The INS method for soil carbon content measurements provides a non-destructive, non-invasive tool, which can be optimized in order to develop a system for in field measurements
Space transfer with ground-based laser/electric propulsion
Landis, Geoffrey A.; Stavnes, Mark; Oleson, Steve; Bozek, John
1993-01-01
A new method of providing power to space vehicles consists of using ground-based lasers to beam power to photovoltaic receivers in space. This can be used as a power source for electrically propelled orbital transfer vehicles.
International Nuclear Information System (INIS)
Graphical abstract: - Highlights: • Mixed P25 nanoparticles and large rutile particles were employed to form a top scattering layer. • The top scattering layer exhibits superior light scattering effect. • The bottom nanocrystalline TiO2 layer can make good use of the back-scattered light. • Bilayer TiO2 photoanode shows faster interfacial electron transfer and slower charge recombination process. • Bilayer photoanode enhances the DSSC efficiency by a factor of 25%. - Abstract: Herein, we report a bilayer TiO2 photoanode composed of nanocrystalline TiO2 (NCT) bottom layer and mixed P25 nanoparticles and large rutile particles (PR) top scattering layer. The present structure performs well in solar light harvesting which is mainly attributed to the fact that the top scattering layer exhibits superior light scattering effect and meanwhile the NCT bottom layer with large dye-loading capacity can make better use of the back-scattered light. Moreover, electrochemical impedance spectroscopy and open circuit voltage decay measurements demonstrate that DSSC based on bilayer photoanode shows faster interfacial electron transfer and slower charge recombination process than that based on NCT monolayer photoanode. These advantages render the DSSCs based on NCT-PR bilayer photoanode exhibiting superior performance under AM1.5G simulated solar irradiation. As an example, by tuning mass ratio between P25 nanoparticles and large rutile particles in the top scattering layer, the DSSC based on NCT-PR bilayer photoanode exhibits an optimum solar energy conversion efficiency of 9.0%, which is about 1.25 times higher than that of monolayer NCT device (7.2%) with the same film thickness
Omari, Khalid
This thesis investigated the development and assessment of a simple parameterization of the multiple scattering within canopies assuming the single scattering field is known and the background beneath the canopy is completely absorbing. The parameterization is based on the concept of spectral invariants related to recollision and escape probabilities from vegetation canopies. The simplified approach is evaluated against detailed 3-D ray tracing model, PARCINOPY, as well as reference datasets from the Radiation Modelling Intercomparison Experiment On-Line Checker. Comparison with homogenous canopies simulated with PARCINOPY showed that the model's performance is best in both the solar principal and perpendicular planes at low and mid LAI levels for all solar zenith angles. The comparison to the On-line Checker datasets shows also that the model is a suitable approach to describe the multiple scattering components of physically based models. This simple parameterization is then incorporated into the Four Scale Linear Model for Anisotropie Reflectance (FLAIR) canopy radiative transfer model to enhance the description of the spectrally dependant multiple scattered radiation field of a forest canopy. The contribution of the multiply scattered radiation between the canopy and the background is also added to the parameterization of the multiple scattering component. The validation of the new version of the FLAIR model was performed using the multi-angular data sets obtained by the airborne sensor POLarization and Directionality of the Earth's Reflectances (POLDER) during the BOReal Ecosystem-Atmosphere Study (BOREAS) campaign of 1994. The results indicate that this approach is well suited to the FLAIR model. It is also demonstrated that the multiple scattering problem can be parameterized by a limited number of architectural parameters and the leaf scattering coefficient. Finally, the combined canopy-leaf PROFLAIR (PROSPECT + FLAIR) model is used to investigate the
Institute of Scientific and Technical Information of China (English)
Shi De-Heng; Liu Yu-Fang; Sun Jin-Feng; Zhu Zun-Lue; Yang Xiang-Dong
2005-01-01
A complex optical model potential modified by incorporating the concept of bonded atom, with the overlapping effect of electron clouds between two atoms in a molecule taken into consideration, is firstly employed to calculate the differential cross sections, elastic integral cross sections, and moment transfer cross sections for electron scattering from molecular nitrogen over the energy range 300-1000eV by using additivity rule model at Hartree-Fock level. The bondedatom concept is used in the study of the complex optical model potential composed of static, exchange, correlation polarization and absorption contributions. The calculated quantitative molecular differential cross sections, elastic integral cross sections, and moment transfer cross sections are compared with the experimental and theoretical ones wherever available, and they are found to be in good agreement with each other. It is shown that the additivity rule model together with the complex optical model potential modified by incorporating the concept of bonded atom is completely suitable for the calculations of differential cross section, elastic integral cross section and moment transfer cross section over the intermediate- and high-energy ranges.
Compton Scattering Cross Section on the Proton at High Momentum Transfer
Danagoulian, A; Annand, J R M; Bertin, P Y; Bimbot, L; Bosted, P; Calarco, J R; Camsonne, A; Chang, C C; Chang, T H; Chen, J P; Choi, Seonho; Chudakov, E; De Jager, C W; Degtyarenko, P; Deur, A; Dutta, D; Egiyan, K; Gao, H; Garibaldi, F; Gayou, O; Gilman, R; Glamazdin, A; Glashausser, C; Gómez, J; Hamilton, D J; Hansen, J O; Hayes, D; Higinbotham, D W; Hinton, W; Horn, T; Howell, C; Hunyady, T; Hyde-Wright, C E; Jiang, X; Jones, M K; Ketikyan, A; Khandaker, M; Koubarovski, V; Krämer, K; Kumbartzki, G; Laveissière, G; Le Rose, J; Lindgren, R A; Mamyan, V H; Margaziotis, D J; Markowitz, P; McCormick, K; Meziani, Z E; Michaels, R; Moussiegt, P; Nanda, S; Nathan, A M; Nelyubin, V V; Nikolenko, D M; Norum, B E; Paschke, K; Pentchev, L; Perdrisat, C F; Piasetzky, E; Pomatsalyuk, R I; Punjabi, V A; Rachek, Igor A; Radyushkin, A; Reitz, B; Roché, R; Roedelbronn, M; Ron, G; Sabatie, F; Saha, A; Savvinov, N; Shahinyan, A; Shestakov, Yu V; Sirca, S; Slifer, K J; Solvignon, P; Stoler, P; Sulkosky, V; Tajima, S; Todor, L; Vlahovic, B; Voskanyan, H; Wang, K; Weinstein, L B; Wojtsekhowski, B; Xiang, H; Zheng, X; Zhu, L
2007-01-01
Cross-section values for Compton scattering on the proton were measured at 25 kinematic settings over the range s = 5-11 and -t = 2-7 GeV2 with statistical accuracy of a few percent. The scaling power for the s-dependence of the cross section at fixed center of mass angle was found to be 8.0 +/ 0.2, strongly inconsistent with the prediction of perturbative QCD. The observed cross-section values are in fair agreement with the calculations using the handbag mechanism, in which the external photons couple to a single quark.
Compton Scattering Cross Section on the Proton at High Momentum Transfer
Energy Technology Data Exchange (ETDEWEB)
A. Danagoulian; V.H. Mamyan; M. Roedelbronn; K.A. Aniol; J.R.M. Annand; P.Y. Bertin; L. Bimbot; P. Bosted; J.R. Calarco; A. Camsonne; C.C. Chang; T.-H. Chang; J.-P. Chen; Seonho Choi; E. Chudakov; P. Degtyarenko; C.W. de Jager; A. Deur; D. Dutta; K. Egiyan; H. Gao; F. Garibaldi; O. Gayou; R. Gilman; A. Glamazdin; C. Glashausser; J. Gomez; D.J. Hamilton; J.-O. Hansen; D. Hayes; D.W. Higinbotham; W. Hinton; T. Horn; C. Howell; T. Hunyady; C.E. Hyde-Wright; X. Jiang; M.K. Jones; M. Khandaker; A. Ketikyan; V. Koubarovski; K. Kramer; G. Kumbartzki; G. Laveissiere; J. LeRose; R.A. Lindgren; D.J. Margaziotis; P. Markowitz; K. McCormick; Z.-E. Meziani; R. Michaels; P. Moussiegt; S. Nanda; A.M. Nathan; D.M. Nikolenko; V. Nelyubin; B.E. Norum; K. Paschke; L. Pentchev; C.F. Perdrisat; E. Piasetzky; R. Pomatsalyuk; V.A. Punjabi; I. Rachek; A. Radyushkin; B. Reitz; R. Roche; G. Ron; F. Sabatie; A. Saha; N. Savvinov; A. Shahinyan; Y. Shestakov; S. Sirca; K. Slifer; P. Solvignon; P. Stoler; S. Tajima; V. Sulkosky; L. Todor; B. Vlahovic; L.B. Weinstein; K. Wang; B. Wojtsekhowski; H. Voskanyan; H. Xiang; X. Zheng; L. Zhu
2007-01-29
Cross-section values for Compton scattering on the proton were measured at 25 kinematic settings over the range s = 5-11 and -t = 2-7 GeV2 with statistical accuracy of a few percent. The scaling power for the s-dependence of the cross section at fixed center of mass angle was found to be 8.0 +/- 0.2, strongly inconsistent with the prediction of perturbative QCD. The observed cross section values are in fair agreement with the calculations using the handbag mechanism, in which the external photons couple to a single quark.
Compton Scattering Cross Section on the Proton at High Momentum Transfer
International Nuclear Information System (INIS)
Cross-section values for Compton scattering on the proton were measured at 25 kinematic settings over the range s = 5-11 and -t = 2-7 GeV2 with statistical accuracy of a few percent. The scaling power for the s-dependence of the cross section at fixed center of mass angle was found to be 8.0 +/- 0.2, strongly inconsistent with the prediction of perturbative QCD. The observed cross section values are in fair agreement with the calculations using the handbag mechanism, in which the external photons couple to a single quark
Compton-Scattering Cross Section on the Proton at High Momentum Transfer
International Nuclear Information System (INIS)
Cross-section values for Compton scattering on the proton were measured at 25 kinematic settings over the range s=5-11 and -t=2-7 GeV2 with a statistical accuracy of a few percent. The scaling power for the s dependence of the cross section at fixed center-of-mass angle was found to be 8.0±0.2, strongly inconsistent with the prediction of perturbative QCD. The observed cross-section values are in fair agreement with the calculations using the handbag mechanism, in which the external photons couple to a single quark
New approach to polarized proton scattering based on Dirac dynamics
International Nuclear Information System (INIS)
The Dirac impulse approximation has to date provided dramatic improvement in our ability to predict, with no free parameters, spin observables in proton-nucleus elastic scattering at intermediate energies. The key ingredients of this approach are Dirac propagation and the nucleon-nucleon invariant amplitudes. So far, local approximations to the NN amplitudes have been used. The standard NN representation in terms of Dirac scalar, vector, and so on, parts which is free of kinematical singularities seems to naturally predict the correct coupling to negative energy states for energies above 300 MeV. At low energy, this coupling is subject to an ambiguity between pseudoscalar and pseudovector πN coupling mechanisms and it is evident that the pseudoscalar coupling treated in a local approximation causes too much scalar-vector difference and thus too large pair contributions. Once this problem is remedied, the Dirac optical potential is expected to be calculable from a nucleon-nucleon quasi-potential over the range 0 to 1000 MeV. For the energy region above about 300 MeV, the large scalar and vector potentials of Dirac phenomenology are seen to be accurately predicted by the impulse approximation. Work by Shakin and collaborators provides complementary results at low energy based on a nuclear matter g-matrix. A basic conclusion is that relativistic spin effects cannot be neglected in nuclear physics. 36 references
Beam Diagnostics for Laser Undulator Based on Compton Backward Scattering
Kuroda, R
2005-01-01
A compact soft X-ray source is required in various research fields such as material and biological science. The laser undulator based on Compton backward scattering has been developed as a compact soft X-ray source for the biological observation at Waseda University. It is performed in a water window region (250eV - 500 eV) using the interaction between 1047 nm Nd:YLF laser (10ps FWHM) and about 5 MeV high quality electron beam (10ps FWHM) generated from rf gun system. The range of X-ray energy in the water window region has K-shell absorption edges of Oxygen, Carbon and Nitrogen, which mainly constitute of living body. Since the absorption coefficient of water is much smaller than the protein's coefficient in this range, a dehydration of the specimens is not necessary. To generate the soft X-ray pulse stably, the electron beam diagnostics have been developed such as the emittance measurement using double slit scan technique, the bunch length measurement using two frequency analysis technique. In this confere...
Fast calculation of object infrared spectral scattering based on CUDA
Li, Liang-chao; Niu, Wu-bin; Wu, Zhen-sen
2010-11-01
Computational unified device architecture (CUDA) is used for paralleling the spectral scattering calculation from non-Lambertian object of sky and earth background irradiation. The bidirectional reflectance distribution function (BRDF) of five parameter model is utilized in object surface element scattering calculation. The calculation process is partitioned into many threads running in GPU kernel and each thread computes a visible surface element infrared spectral scattering intensity in a specific incident direction, all visible surface elements' intensity are weighted and averaged to obtain the object surface scattering intensity. The comparison of results of the CPU calculation and CUDA parallel calculation of a cylinder shows that the CUDA parallel calculation speed improves more than two hundred times in meeting the accuracy, with a high engineering value.
The Data Transfer Kit: A geometric rendezvous-based tool for multiphysics data transfer
International Nuclear Information System (INIS)
The Data Transfer Kit (DTK) is a software library designed to provide parallel data transfer services for arbitrary physics components based on the concept of geometric rendezvous. The rendezvous algorithm provides a means to geometrically correlate two geometric domains that may be arbitrarily decomposed in a parallel simulation. By repartitioning both domains such that they have the same geometric domain on each parallel process, efficient and load balanced search operations and data transfer can be performed at a desirable algorithmic time complexity with low communication overhead relative to other types of mapping algorithms. With the increased development efforts in multiphysics simulation and other multiple mesh and geometry problems, generating parallel topology maps for transferring fields and other data between geometric domains is a common operation. The algorithms used to generate parallel topology maps based on the concept of geometric rendezvous as implemented in DTK are described with an example using a conjugate heat transfer calculation and thermal coupling with a neutronics code. In addition, we provide the results of initial scaling studies performed on the Jaguar Cray XK6 system at Oak Ridge National Laboratory for a worse-case-scenario problem in terms of algorithmic complexity that shows good scaling on 0(1 x 104) cores for topology map generation and excellent scaling on 0(1 x 105) cores for the data transfer operation with meshes of O(1 x 109) elements. (authors)
International Nuclear Information System (INIS)
Our work presents computations via a vectorial radiative transfer model of the polarimetric and angular light scattered by a stratified dense medium with small and intermediate optical thickness. We report the validation of this model using analytical results and different computational methods like stochastic algorithms. Moreover, we check the model with experimental data from a specific scatterometer developed at the Onera. The advantages and disadvantages of a radiative approach are discussed. This paper represents a step toward the characterization of particles in dense media involving multiple scattering. -- Highlights: • A vectorial radiative transfer model to simulate the light scattered by stratified layers is developed. • The vectorial radiative transfer equation is solved using an adding–doubling technique. • The results are compared to analytical and stochastic data. • Validation with experimental data from a scatterometer developed at Onera is presented
A New Glauber Theory based on Multiple Scattering Theory
Yahiro, Masanobu; Minomo, Kosho; Ogata, Kazuyuki; Kawai, Mitsuji
2008-01-01
Glauber theory for nucleus-nucleus scattering at high incident energies is reformulated so as to become applicable also for the scattering at intermediate energies. We test validity of the eikonal and adiabatic approximations used in the formulation, and discuss the relation between the present theory and the conventional Glauber calculations with either the empirical nucleon-nucleon profile function or the modified one including the in-medium effect.
Novel Boron-10-based detectors for Neutron Scattering Science
Piscitelli, Francesco; project, for the ILL/ESS/LiU collaboration for the development of the B10 detector technology in the framework of the CRISP
2015-01-01
Nowadays neutron scattering science is increasing its instrumental power. Most of the neutron sources in the world are pushing the development of their technologies to be more performing. The neutron scattering development is also pushed by the European Spallation Source (ESS) in Sweden, a neutron facility which has just started construction. Concerning small area detectors (1m^2), the 3He technology, which is today cutting edge, is reaching fundamental limits in its development. Counting rat...
Chen, Lin; Wu, Wen-Bin; Liu, Pin-Yang; Xiao, Yun-Qing; Li, Guo-Peng; Liu, Yi-Ran; Jiang, Hao-Yu; Guo, Yan-Ling; Chen, Xi-Meng
2016-08-01
For Li+ and Na+ ions scattered from high work function metal surfaces, efficient neutralization is observed, and it cannot be explained by the conventional free electron model. In order to explain these experimental data, we investigate the velocity-dependent neutral fraction with the modified Brako–Newns (BN) model. The calculated results are in agreement with the experimental data. We find that the parallel velocity effect plays an important role in neutralizing the Li+ and Na+ ions for large angle scattering. The nonmonotonic velocity behavior of neutral fraction is strongly related to the distance-dependent coupling strength between the atomic level and metal states. Project supported by the National Natural Science Foundation of China (Grant Nos. 11405078 and 11474140), the Fundamental Research Funds for the Central Universities, China (Grant Nos. lzujbky-2014-169 and lzujbky-2015-244), the Project sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, the State Education Ministry, and the National Students’ Innovation and Entrepreneurship Training Program (Grant Nos. 201410730069 and 201510730078).
Elastic electron scattering at low momentum transfer and muonic X-rays
International Nuclear Information System (INIS)
Mean square charge radius obtained at low momentum transfer is discussed in model-independent way. Muonic X-ray energies and form factors being expressed in terms of generalized moments of the charge density, the linear constraint functions from Friar and Negele are used to obtain an idea of the model-dependent error, r2.208Pb, 4Ca and 4He are considered as examples
Energy Technology Data Exchange (ETDEWEB)
Fanelli, Cristiano V. [Sapienza Univ. of Rome (Italy)
2015-03-01
In this thesis work, results of the analysis of the polarization transfers measured in real Compton scattering (RCS) by the Collaboration E07-002 at the Je fferson Lab Hall-C are presented. The data were collected at large scattering angle (theta_cm = 70deg) and with a polarized incident photon beam at an average energy of 3.8 GeV. Such a kind of experiments allows one to understand more deeply the reaction mechanism, that involves a real photon, by extracting both Compton form factors and Generalized Parton Distributions (GPDs) (also relevant for possibly shedding light on the total angular momentum of the nucleon). The obtained results for the longitudinal and transverse polarization transfers K_LL and K_LT, are of crucial importance, since they confirm unambiguously the disagreement between experimental data and pQCD prediction, as it was found in E99-114 experiment, and favor the Handbag mechanism. The E99-114 and E07-002 results can contribute to attract new interest on the great yield of the Compton scattering by a nucleon target, as demonstrated by the recent approval of an experimental proposal submitted to the Jefferson Lab PAC 42 for a Wide-angle Compton Scattering experiment, at 8 and 10 GeV Photon Energies. The new experiments approved to run with the updated 12 GeV electron beam at JLab, are characterized by much higher luminosities, and a new GEM tracker is under development to tackle the challenging backgrounds. Within this context, we present a new multistep tracking algorithm, based on (i) a Neural Network (NN) designed for a fast and efficient association of the hits measured by the GEM detector which allows the track identification, and (ii) the application of both a Kalman filter and Rauch-Tung-Striebel smoother to further improve the track reconstruction. The full procedure, i.e. NN and filtering, appears very promising, with high performances in terms of both association effciency and reconstruction accuracy, and these preliminary results will
Tominaga, Nozomu; Blinnikov, Sergei I
2015-01-01
We develop a time-dependent multi-group multidimensional relativistic radiative transfer code, which is required to numerically investigate radiation from relativistic fluids involved in, e.g., gamma-ray bursts and active galactic nuclei. The code is based on the spherical harmonic discrete ordinate method (SHDOM) that evaluates a source function including anisotropic scattering in spherical harmonics and implicitly solves the static radiative transfer equation with a ray tracing in discrete ordinates. We implement treatments of time dependence, multi-frequency bins, Lorentz transformation, and elastic Thomson and inelastic Compton scattering to the publicly available SHDOM code. Our code adopts a mixed frame approach; the source function is evaluated in the comoving frame whereas the radiative transfer equation is solved in the laboratory frame. This implementation is validated with various test problems and comparisons with results of a relativistic Monte Carlo code. These validations confirm that the code ...
International Nuclear Information System (INIS)
Elastic scattering of heavy-ions 16O and 28Si on 59Co, 109Ag and 130Te have been studied at laboratory incident energies between 80 and 140MeV. The optical model was used to analyse elastic angular distributions and different methods for determining the total reaction cross section have been compared. Transfer reactions induced by 28Si on 130Te have been studied at incident energy superior to the Coulomb barrier in the ratio of 1.27. A study of these reactions shows the transition between the quasi-elastic reactions and deep inelastic reactions coresponding to the phenomenon of friction. The diffusion model is used for the analysis of these results
Zamoum, R.; Lavagna, M.; Crépieux, A.
2016-06-01
We calculate the nonsymmetrized current noise in a quantum dot connected to two reservoirs by using the nonequilibrium Green function technique. We show that both the current autocorrelator (inside a single reservoir) and the current cross-correlator (between the two reservoirs) are expressed in terms of transmission amplitude and coefficient through the barriers. We identify the different energy-transfer processes involved in each contribution to the autocorrelator, and we highlight the fact that when there are several physical processes, the contribution results from a coherent superposition of scattering paths. Varying the gate and bias voltages, we discuss the profile of the differential Fano factor in light of recent experiments, and we identify the conditions for having a distinct value for the autocorrelator in the left and right reservoirs.
Scatter correction method for cone-beam CT based on interlacing-slit scan
International Nuclear Information System (INIS)
Cone-beam computed tomography (CBCT) has the notable features of high efficiency and high precision, and is widely used in areas such as medical imaging and industrial non-destructive testing. However, the presence of the ray scatter reduces the quality of CT images. By referencing the slit collimation approach, a scatter correction method for CBCT based on the interlacing-slit scan is proposed. Firstly, according to the characteristics of CBCT imaging, a scatter suppression plate with interlacing slits is designed and fabricated. Then the imaging of the scatter suppression plate is analyzed, and a scatter correction calculation method for CBCT based on the image fusion is proposed, which can splice out a complete set of scatter suppression projection images according to the interlacing-slit projection images of the left and the right imaging regions in the scatter suppression plate, and simultaneously complete the scatter correction within the flat panel detector (FPD). Finally, the overall process of scatter suppression and correction is provided. The experimental results show that this method can significantly improve the clarity of the slice images and achieve a good scatter correction. (interdisciplinary physics and related areas of science and technology)
Scatter correction method for cone-beam CT based on interlacing-slit scan
Huang, Kui-Dong; Zhang, Hua; Shi, Yi-Kai; Zhang, Liang; Xu, Zhe
2014-09-01
Cone-beam computed tomography (CBCT) has the notable features of high efficiency and high precision, and is widely used in areas such as medical imaging and industrial non-destructive testing. However, the presence of the ray scatter reduces the quality of CT images. By referencing the slit collimation approach, a scatter correction method for CBCT based on the interlacing-slit scan is proposed. Firstly, according to the characteristics of CBCT imaging, a scatter suppression plate with interlacing slits is designed and fabricated. Then the imaging of the scatter suppression plate is analyzed, and a scatter correction calculation method for CBCT based on the image fusion is proposed, which can splice out a complete set of scatter suppression projection images according to the interlacing-slit projection images of the left and the right imaging regions in the scatter suppression plate, and simultaneously complete the scatter correction within the flat panel detector (FPD). Finally, the overall process of scatter suppression and correction is provided. The experimental results show that this method can significantly improve the clarity of the slice images and achieve a good scatter correction.
Exclusive meson pair production in gamma* gamma scattering at small momentum transfer
Lansberg, J P; Szymanowski, L
2006-01-01
We study the exclusive production of pi pi and rho pi in hard gamma* gamma scattering in the forward kinematical region where the virtuality of one photon provides us with a hard scale in the process. The newly introduced concept of Transition Distribution Amplitudes (TDA) is used to perform a QCD calculation of these reactions thanks to two simple models for TDAs. Cross sections for rho pi and pi pi production are evaluated and compared to the possible background from the Bremsstrahlung process. This picture may be tested at intense electron-positron colliders such as CLEO and B factories. The cross section e gamma -> e' pi0 pi0 is finally shown to provide a possible determination of the pi0 axial form factor, FA, at small t, which seems not to be measurable elsewhere.
Nuclear effects in deep inelastic lepton nucleon scattering at different momentum transfers
International Nuclear Information System (INIS)
The ratio of the structure function F2sup(A)(x) of a nucleus A to that of deuterium F2sup(D)(x)is computed for A = Fe, Al; 12C and 4He. The difference between lepton-nucleus and lepton-nucleon scattering is explained by a fraction g of the valence quarks of nuclear matter moving effectively in bags of doubled size (i.e. α's). The difference between EMC and SLAC data stems from the different effective quark mass, which is close to zero at -q2 = 100 GeV2, but (140 +- 25) MeV, at 2> = 3 GeV2. A cluster probability of g = 15% (10%) fits the Fe (Al) data well; g = 1/3 is predicted for 4He (and 12C) on grounds of the Barshay three gluon force. (orig.)
Measurement of np elastic scattering at high energies and very small momentum transfer
International Nuclear Information System (INIS)
The np elastic differential cross section has been measured for incident neutron momenta 100-400 GeV/c in the vertical stroketvertical stroke range 6 x 10-6 - 5 x 10-1 (GeV/c)2. The np data of this experiment provide a first direct measurement of the hadronic amplitude for vertical stroketvertical stroke -2 (GeV/c)2, which is consistent with the extrapolations from higher vertical stroketvertical stroke values. Our data for vertical stroketvertical stroke -4 (GeV/c)2 are consistent with a rise which can be attributed to Schwinger scattering, caused by the interaction of the neutron magnetic moment with the proton. (orig.)
A measurement of the spin transfer observable DNN' for p+p elastic scattering at Tp=200 MeV
International Nuclear Information System (INIS)
Recent analyses of NN and πN scattering data have resulted in values for the πNN coupling constant which are significantly smaller than those obtained prior to 1987. These controversial results prompted us to investigate the usefulness of high-quality spin measurements towards resolving this issue. We found that the normal component spin transfer observable DNN' for p+p elastic scattering is very sensitive to g20, particularly at small angles. We have therefore determined precise values of DNN' for this reaction for θlab=5.0 degree, 7.2 degree, 8.4 degree, 9.7 degree, 11.8 degree, 14.6 degree, 18.8 degree, 24 degree, 30 degree, and 38 degree at an incident beam energy of 200 MeV. The forward-going proton was detected in the IUCF K600 spectrometer and the coincident recoil proton was detected in a Si/CsI detector telescope. Our preliminary DNN' values are reproduced reasonably well by Arndt's C200 solution, the Nijmegen PWA93, and the Nijmegen I potential, but differ severely from both Arndt's SM94 global solution and the predictions of the Bonn potential
Tikhonov regularization-based operational transfer path analysis
Cheng, Wei; Lu, Yingying; Zhang, Zhousuo
2016-06-01
To overcome ill-posed problems in operational transfer path analysis (OTPA), and improve the stability of solutions, this paper proposes a novel OTPA based on Tikhonov regularization, which considers both fitting degrees and stability of solutions. Firstly, fundamental theory of Tikhonov regularization-based OTPA is presented, and comparative studies are provided to validate the effectiveness on ill-posed problems. Secondly, transfer path analysis and source contribution evaluations for numerical cases studies on spherical radiating acoustical sources are comparatively studied. Finally, transfer path analysis and source contribution evaluations for experimental case studies on a test bed with thin shell structures are provided. This study provides more accurate transfer path analysis for mechanical systems, which can benefit for vibration reduction by structural path optimization. Furthermore, with accurate evaluation of source contributions, vibration monitoring and control by active controlling vibration sources can be effectively carried out.
Broadband and Broad-Angle Low-Scattering Metasurface Based on Hybrid Optimization Algorithm
Wang, Ke; Zhao, Jie; Cheng, Qiang; Dong, Di Sha; Cui, Tie Jun
2014-01-01
A broadband and broad-angle low-scattering metasurface is designed, fabricated, and characterized. Based on the optimization algorithm and far-field scattering pattern analysis, we propose a rapid and efficient method to design metasurfaces, which avoids the large amount of time-consuming electromagnetic simulations. Full-wave simulation and measurement results show that the proposed metasurface is insensitive to the polarization of incident waves, and presents good scattering-reduction properties for oblique incident waves. PMID:25089367
Broadband and Broad-Angle Low-Scattering Metasurface Based on Hybrid Optimization Algorithm
Ke Wang; Jie Zhao; Qiang Cheng; Di Sha Dong; Tie Jun Cui
2014-01-01
A broadband and broad-angle low-scattering metasurface is designed, fabricated, and characterized. Based on the optimization algorithm and far-field scattering pattern analysis, we propose a rapid and efficient method to design metasurfaces, which avoids the large amount of time-consuming electromagnetic simulations. Full-wave simulation and measurement results show that the proposed metasurface is insensitive to the polarization of incident waves, and presents good scattering-reduction prope...
Photon Acceleration of Laser-plasma Based on Compton Scattering
Institute of Scientific and Technical Information of China (English)
HAO Dong-shan; XIE Hong-jun
2006-01-01
The one-dimensional electron density disturbance is studied by using the inelastic collision model of the relativity electron and photon group, the relativity theory, the momentum equation and the continuity equation, which is generated by a driving laser pulse and scattered laser pulse propagating through a tenuous plasma, and the electron density disturbance is closely associated with the incident laser and scattering laser. The electron plasma wave(EPW)is formed by the propagation of the electron density disturbance. Owing to the action of EPW, the increasing of the frequency of the photons in the incident laser pulses that there is a distance with the driving laser pulses is studied by using optical metric. The results show that it is possible that the photon will gain higher energy from the EPW when photon number is decreased and one-photon Compton scattering enters, the photon will be accelerated.
Inclusive electron scattering from nuclei in the quasielastic region at large momentum transfer
Energy Technology Data Exchange (ETDEWEB)
Fomin, Nadia [California Inst. of Technology (CalTech), Pasadena, CA (United States)
2008-12-01
Experiment E02-019, performed in Hall C at the Thomas Jefferson National Accelerator Facility (TJNAF), was a measurement of inclusive electron cross sections for several nuclei (^{2}H,^{3}He, ^{4}He, ^{9}Be,^{12}C, ^{63}Cu, and ^{197}Au) in the quasielastic region at high momentum transfer. In the region of low energy transfer, the cross sections were analyzed in terms of the reduced response, F(y), by examining its y-scaling behavior. The data were also examined in terms of the nuclear structure function νW^{A}_{ 2} and its behavior in x and the Nachtmann variable ξ. The data show approximate scaling of νW^{A}_{ 2} in ξ for all targets at all kinematics, unlike scaling in x, which is confined to the DIS regime. However, y-scaling observations are limited to the kinematic region dominated by the quasielastic response (y <0), where some scaling violations arising from FSIs are observed.
Inductive energy transfer system based on drone
Izquierdo Perez, Ignacio; Hontecillas Guinart, Lluis
2016-01-01
The aim of this project is to model and validate an inductive system in order to be able to power wirelessly a sensor. The design of the inductive system must be small and light enough to fulfil the requirements of a nano-quadcopter, in which the system is going to be outfitted. Recent investigations about inductive systems added to the Energy Harvesting trend, predict a future based on wireless power. Thereby, the possibility to change the current "wire-dependence" of any device. At the begi...
Electromagnetic Field Scattering on rf-SQUID Based Metasurfaces
Directory of Open Access Journals (Sweden)
Сaputo J.G
2015-01-01
Full Text Available Electromagnetic field scattering on a 2D array of rf-SQUIDs is considered. We show that the scattering changes for large amplitudes of the incident electromagnetic wave; above a critical amplitude, two different refraction states occur (bistability. In particular, for these two states, the transmitted wave polarization and angle of refraction are different. One could then switch the direction of propagation of the electromagnetic wave and its polarization with a “thin film”, whose thickness is much smaller than the wavelength.
Vasilkov, Alexander; Joiner, Joanna; Spurr, Robert; Bhartia, Pawan K.; Levelt, Pieternel; Stephens, Graeme
2009-01-01
In this paper we examine differences between cloud pressures retrieved from the Ozone Monitoring Instrument (OMI) using the ultraviolet rotational Raman scattering (RRS) algorithm and those from the thermal infrared (IR) Aqua/MODIS. Several cloud data sets are currently being used in OMI trace gas retrieval algorithms including climatologies based on IR measurements and simultaneous cloud parameters derived from OMI. From a validation perspective, it is important to understand the OMI retrieved cloud parameters and how they differ with those derived from the IR. To this end, we perform radiative transfer calculations to simulate the effects of different geophysical conditions on the OMI RRS cloud pressure retrievals. We also quantify errors related to the use of the Mixed Lambert-Equivalent Reflectivity (MLER) concept as currently implemented of the OMI algorithms. Using properties from the Cloudsat radar and MODIS, we show that radiative transfer calculations support the following: (1) The MLER model is adequate for single-layer optically thick, geometrically thin clouds, but can produce significant errors in estimated cloud pressure for optically thin clouds. (2) In a two-layer cloud, the RRS algorithm may retrieve a cloud pressure that is either between the two cloud decks or even beneath the top of the lower cloud deck because of scattering between the cloud layers; the retrieved pressure depends upon the viewing geometry and the optical depth of the upper cloud deck. (3) Absorbing aerosol in and above a cloud can produce significant errors in the retrieved cloud pressure. (4) The retrieved RRS effective pressure for a deep convective cloud will be significantly higher than the physical cloud top pressure derived with thermal IR.
International Nuclear Information System (INIS)
Transient radiative transfer (TRT) in one-dimensional (1-D) homogeneous and inhomogeneous media with ultra-short pulse laser irradiated is investigated by means of the finite volume method (FVM) in the present research. Comparing with the steady radiative transfer (SRT), the extra time-resolved information can be obtained in TRT. Meanwhile, the propagation speed of short-pulse laser and the geometric thickness of the media should be considered in the simulation of TRT problem besides the optical thickness. A new nondimensional number ζ=ctp/L is presented. For the homogeneous media, the temporal signals would overlap one another with different combinations of the pulse duration and the thickness of the media with the same ζ. Furthermore, in two-layer media, the influence of the scattering albedo, optical thickness and the geometric thickness of the participating media on 'dual-peak' are studied thoroughly. The improved expression of the 'local minimum' in the 'dual-peak' and the interface location of the multi-layer media are provided.
Bumpless Transfer between Observer-based Gain Scheduled Controllers
DEFF Research Database (Denmark)
Bendtsen, Jan Dimon; Stoustrup, Jakob; Trangbæk, Klaus
2005-01-01
This paper deals with bumpless transfer between a number of observer-based controllers in a gain scheduling architecture. Linear observer-based controllers are designed for a number of linear approximations of a nonlinear system in a set of operating points, and gain scheduling control can subseq...
Concept Development and Transfer in Context-Based Science Education
Gilbert, John K.; Bulte, Astrid M. W.; Pilot, Albert
2011-01-01
"Context-based courses" are increasingly used in an address to the major challenges that science education currently faces: lack of clear purpose, content overload, incoherent learning by students, lack of relevance to students, and lack of transfer of learning to new contexts. In this paper, four criteria for the design of context-based courses…
Transfer Pricing Based on Actual versus Standard Costs
Lengsfeld, Stephan; Schiller, Ulf
2003-01-01
The use of information plays an important role in the choice of transfer prices (TP). We discuss the information provision of two centralized mechanisms, namely, actual-cost and standard-cost based TP. Actual cost based TP use all available cost information whereas standard cost based TP only reflect expected cost. We analyze the impact of either regime on the incentives of two divisions that make upfront investments and - later - trade an intermediate good. Actual cost based TP allow for a f...
Total wave based fast direct solver for volume scattering problems
Chen, Yu
2013-01-01
We present a fast direct solver for the volume scattering problem of the Helmholtz equation. The algorithm is faster than existing methods. Moreover, discretization for our method is much simpler and more accurate than that for finite difference, finite elements, and integral equations.
Sekiguchi, K; Witala, H; Ermisch, K; Glöckle, W; Golak, J; Hatano, M; Kamada, H; Kalantar-Nayestanaki, N; Kato, H; Maeda, Y; Nishikawa, J; Nogga, A; Ohnishi, T; Okamura, H; Saitô, T; Sakamoto, N; Sakoda, S; Satou, Y; Suda, K; Tamii, A; Uchigashima, T; Uesaka, T; Wakasa, T; Yako, K
2004-01-01
The deuteron to proton polarization transfer coefficients for the $d$--$p$ elastic scattering were precisely measured with an incoming deuteron energy of 135 MeV/u at the RIKEN Accelerator Research Facility. The data are compared to theoretical predictions based on exact solutions of three-nucleon Faddeev equations with high--precision nucleon--nucleon forces combined with different three-nucleon forces (3NFs), representing the current, most popular models: the $2\\pi$-exchange Tucson-Melbourne model, a modification thereof closer to chiral symmetry TM'(99), and the Urbana IX 3NF. Theory predicts large 3NF effects, especially in the angular range around the cross section minimum, but the present data only partially concurs, predominantly for $K_{xx}^{y'}-K_{yy}^{y'}$ ($K_{xx}^{y'}$, $K_{yy}^{y'}$). For the induced polarization, $P^{y'}$, the TM$'$(99) and Urbana IX 3NFs reproduce the data, but the Tucson-Melbourne 3NF fails to describe the data. For the polarization transfer coefficients, $K_{y}^{y'}$ and $K_{...
SU-E-I-08: Investigation of Deconvolution Methods for Blocker-Based CBCT Scatter Estimation
International Nuclear Information System (INIS)
Purpose: To investigate whether deconvolution methods can improve the scatter estimation under different blurring and noise conditions for blocker-based scatter correction methods for cone-beam X-ray computed tomography (CBCT). Methods: An “ideal” projection image with scatter was first simulated for blocker-based CBCT data acquisition by assuming no blurring effect and no noise. The ideal image was then convolved with long-tail point spread functions (PSF) with different widths to mimic the blurring effect from the finite focal spot and detector response. Different levels of noise were also added. Three deconvolution Methods: 1) inverse filtering; 2) Wiener; and 3) Richardson-Lucy, were used to recover the scatter signal in the blocked region. The root mean square error (RMSE) of estimated scatter serves as a quantitative measure for the performance of different methods under different blurring and noise conditions. Results: Due to the blurring effect, the scatter signal in the blocked region is contaminated by the primary signal in the unblocked region. The direct use of the signal in the blocked region to estimate scatter (“direct method”) leads to large RMSE values, which increase with the increased width of PSF and increased noise. The inverse filtering is very sensitive to noise and practically useless. The Wiener and Richardson-Lucy deconvolution methods significantly improve scatter estimation compared to the direct method. For a typical medium PSF and medium noise condition, both methods (∼20 RMSE) can achieve 4-fold improvement over the direct method (∼80 RMSE). The Wiener method deals better with large noise and Richardson-Lucy works better on wide PSF. Conclusion: We investigated several deconvolution methods to recover the scatter signal in the blocked region for blocker-based scatter correction for CBCT. Our simulation results demonstrate that Wiener and Richardson-Lucy deconvolution can significantly improve the scatter estimation
Hindi to English Transfer Based Machine Translation System
Directory of Open Access Journals (Sweden)
Shashi Pal Singh
2015-06-01
Full Text Available In large societies like India there is a huge demand to convert one human language into another. Lots of work has been done in this area. Many transfer based MTS have developed for English to other languages, as MANTRA CDAC Pune, MATRA CDAC Pune, SHAKTI IISc Bangalore and IIIT Hyderabad. Still there is a little work done for Hindi to other languages. Currently we are working on it. In this paper we focus on designing a system, that translate the document from Hindi to English by using transfer based approach. This system takes an input text check its structure through parsing. Reordering rules are used to generate the text in target language. It is better than Corpus Based MTS because Corpus Based MTS require large amount of word aligned data for translation that is not available for many languages while Transfer Based MTS requires only knowledge of both the languages (source language and target language to make transfer rules. We get correct translation for simple assertive sentences and almost correct for complex and compound sentences.
Electron scattering times in ZnO based polar heterostructures
International Nuclear Information System (INIS)
The remarkable historic advances experienced in condensed matter physics have been enabled through the continued exploration and proliferation of increasingly richer and cleaner material systems. In this work, we report on the scattering times of charge carriers confined in state-of-the-art MgZnO/ZnO heterostructures displaying electron mobilities in excess of 106 cm2/V s. Through an examination of low field quantum oscillations, we obtain the effective mass of charge carriers, along with the transport and quantum scattering times. These times compare favorably with high mobility AlGaAs/GaAs heterostructures, suggesting the quality of MgZnO/ZnO heterostructures now rivals that of traditional semiconductors
Electron scattering times in ZnO based polar heterostructures
Energy Technology Data Exchange (ETDEWEB)
Falson, J., E-mail: j.falson@fkf.mpg.de [Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656 (Japan); Department of Advanced Materials Science, The University of Tokyo, Kashiwa 277-8561 (Japan); Max Planck Institute for Solid State Research, D-70569 Stuttgart (Germany); Kozuka, Y. [Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656 (Japan); Smet, J. H. [Max Planck Institute for Solid State Research, D-70569 Stuttgart (Germany); Arima, T. [Department of Advanced Materials Science, The University of Tokyo, Kashiwa 277-8561 (Japan); RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan); Tsukazaki, A. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); PRESTO, Japan Science and Technology Agency (JST), Tokyo 102-0075 (Japan); Kawasaki, M. [Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656 (Japan); RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan)
2015-08-24
The remarkable historic advances experienced in condensed matter physics have been enabled through the continued exploration and proliferation of increasingly richer and cleaner material systems. In this work, we report on the scattering times of charge carriers confined in state-of-the-art MgZnO/ZnO heterostructures displaying electron mobilities in excess of 10{sup 6} cm{sup 2}/V s. Through an examination of low field quantum oscillations, we obtain the effective mass of charge carriers, along with the transport and quantum scattering times. These times compare favorably with high mobility AlGaAs/GaAs heterostructures, suggesting the quality of MgZnO/ZnO heterostructures now rivals that of traditional semiconductors.
Scattering theory of the Josephson effect in iron based superconductors
International Nuclear Information System (INIS)
We study the Josephson effect in S±IS± junctions made by a two band superconductor with s± wave symmetry. We derive the Andreev coefficients for the scattering problem at the junction interface and the temperature dependence of the critical current. We predict various features of the Josephson current for certain values of the second band strengths and tunnel barrier amplitude among which a high temperature π state coupling, and a π to 0 transition as the temperature lowers.
Kitzmann, D; Rauer, H
2013-01-01
Owing to their wavelengths dependent absorption and scattering properties, clouds have a strong impact on the climate of planetary atmospheres. Especially, the potential greenhouse effect of CO2 ice clouds in the atmospheres of terrestrial extrasolar planets is of particular interest because it might influence the position and thus the extension of the outer boundary of the classic habitable zone around main sequence stars. We study the radiative effects of CO2 ice particles obtained by different numerical treatments to solve the radiative transfer equation. The comparison between the results of a high-order discrete ordinate method and simpler two-stream approaches reveals large deviations in terms of a potential scattering efficiency of the greenhouse effect. The two-stream methods overestimate the transmitted and reflected radiation, thereby yielding a higher scattering greenhouse effect. For the particular case of a cool M-type dwarf the CO2 ice particles show no strong effective scattering greenhouse eff...
Library-based scatter correction for dedicated cone beam breast CT: a feasibility study
Shi, Linxi; Vedantham, Srinivasan; Karellas, Andrew; Zhu, Lei
2016-04-01
Purpose: Scatter errors are detrimental to cone-beam breast CT (CBBCT) accuracy and obscure the visibility of calcifications and soft-tissue lesions. In this work, we propose practical yet effective scatter correction for CBBCT using a library-based method and investigate its feasibility via small-group patient studies. Method: Based on a simplified breast model with varying breast sizes, we generate a scatter library using Monte-Carlo (MC) simulation. Breasts are approximated as semi-ellipsoids with homogeneous glandular/adipose tissue mixture. On each patient CBBCT projection dataset, an initial estimate of scatter distribution is selected from the pre-computed scatter library by measuring the corresponding breast size on raw projections and the glandular fraction on a first-pass CBBCT reconstruction. Then the selected scatter distribution is modified by estimating the spatial translation of the breast between MC simulation and the clinical scan. Scatter correction is finally performed by subtracting the estimated scatter from raw projections. Results: On two sets of clinical patient CBBCT data with different breast sizes, the proposed method effectively reduces cupping artifact and improves the image contrast by an average factor of 2, with an efficient processing time of 200ms per conebeam projection. Conclusion: Compared with existing scatter correction approaches on CBBCT, the proposed library-based method is clinically advantageous in that it requires no additional scans or hardware modifications. As the MC simulations are pre-computed, our method achieves a high computational efficiency on each patient dataset. The library-based method has shown great promise as a practical tool for effective scatter correction on clinical CBBCT.
Experimental investigation on wake profile detection based on laser scattering by bubbles
Institute of Scientific and Technical Information of China (English)
Liping Su; Weijiang Zhao; Xiaoyong Hu; Deming Ren; Xizhan Liu
2007-01-01
@@ The optical system for detecting wake profiles based on laser backscattering by bubbles at 180° is reported, in which the monostatic optical geometry is adopted and the power density estimation is used to process bubble scattering signal.
Sancho J.; Chin S.; Sagues M.; Loayssa A.; Lloret J.; Gasulla I.; Sales S.; Thevenaz L.; Capmany J.
2010-01-01
A dynamically reconfigurable Microwave Photonic Filter based on True Time Delay generated by Stimulated Brillouin Scattering in optical fibers and separate phase shift of the optical carrier has been experimentally demonstrated, resulting in a flexible tunable Free Spectral Range.
Self-Advanced Propagation of Light Pulse in an Optical Fiber Based on Brillouin Scattering
Chin, Sanghoon; Gonzalez-Herraez, Miguel; Thévenaz, Luc
2007-01-01
We propose a novel method to realize self-induced fast light and signal advancement with no distinct pump source in optical fibers, based on stimulated Brillouin scattering. This scheme will be helpful for real application systems.
Properties of Differential Scattering Section Based on Multi-photon Nonlinear Compton Effect
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Properties of damping electrons in collision with photons based on multi-photon nonlinear Compton effect are investigated. The expressions of the differential scattering section are derived. Several useful conclusions are drawn.
Goel, Narendra S.; Rozehnal, Ivan; Thompson, Richard L.
1991-01-01
A computer-graphics-based model, named DIANA, is presented for generation of objects of arbitrary shape and for calculating bidirectional reflectances and scattering from them, in the visible and infrared region. The computer generation is based on a modified Lindenmayer system approach which makes it possible to generate objects of arbitrary shapes and to simulate their growth, dynamics, and movement. Rendering techniques are used to display an object on a computer screen with appropriate shading and shadowing and to calculate the scattering and reflectance from the object. The technique is illustrated with scattering from canopies of simulated corn plants.
Ultrafast cone-beam CT scatter correction with GPU-based Monte Carlo simulation
Directory of Open Access Journals (Sweden)
Yuan Xu
2014-03-01
Full Text Available Purpose: Scatter artifacts severely degrade image quality of cone-beam CT (CBCT. We present an ultrafast scatter correction framework by using GPU-based Monte Carlo (MC simulation and prior patient CT image, aiming at automatically finish the whole process including both scatter correction and reconstruction within 30 seconds.Methods: The method consists of six steps: 1 FDK reconstruction using raw projection data; 2 Rigid Registration of planning CT to the FDK results; 3 MC scatter calculation at sparse view angles using the planning CT; 4 Interpolation of the calculated scatter signals to other angles; 5 Removal of scatter from the raw projections; 6 FDK reconstruction using the scatter-corrected projections. In addition to using GPU to accelerate MC photon simulations, we also use a small number of photons and a down-sampled CT image in simulation to further reduce computation time. A novel denoising algorithm is used to eliminate MC noise from the simulated scatter images caused by low photon numbers. The method is validated on one simulated head-and-neck case with 364 projection angles.Results: We have examined variation of the scatter signal among projection angles using Fourier analysis. It is found that scatter images at 31 angles are sufficient to restore those at all angles with < 0.1% error. For the simulated patient case with a resolution of 512 × 512 × 100, we simulated 5 × 106 photons per angle. The total computation time is 20.52 seconds on a Nvidia GTX Titan GPU, and the time at each step is 2.53, 0.64, 14.78, 0.13, 0.19, and 2.25 seconds, respectively. The scatter-induced shading/cupping artifacts are substantially reduced, and the average HU error of a region-of-interest is reduced from 75.9 to 19.0 HU.Conclusion: A practical ultrafast MC-based CBCT scatter correction scheme is developed. It accomplished the whole procedure of scatter correction and reconstruction within 30 seconds.----------------------------Cite this
Lossless droplet transfer of droplet-based microfluidic analysis
Kelly, Ryan T; Tang, Keqi; Page, Jason S; Smith, Richard D
2011-11-22
A transfer structure for droplet-based microfluidic analysis is characterized by a first conduit containing a first stream having at least one immiscible droplet of aqueous material and a second conduit containing a second stream comprising an aqueous fluid. The interface between the first conduit and the second conduit can define a plurality of apertures, wherein the apertures are sized to prevent exchange of the first and second streams between conduits while allowing lossless transfer of droplets from the first conduit to the second conduit through contact between the first and second streams.
A Hybrid Metaheuristic for Biclustering Based on Scatter Search and Genetic Algorithms
Nepomuceno, Juan A.; Troncoso, Alicia; Aguilar–Ruiz, Jesús S.
In this paper a hybrid metaheuristic for biclustering based on Scatter Search and Genetic Algorithms is presented. A general scheme of Scatter Search has been used to obtain high-quality biclusters, but a way of generating the initial population and a method of combination based on Genetic Algorithms have been chosen. Experimental results from yeast cell cycle and human B-cell lymphoma are reported. Finally, the performance of the proposed hybrid algorithm is compared with a genetic algorithm recently published.
Bandwidth reconfigurable microwave photonic filter based on stimulated Brillouin scattering
Xiao, Yongchuan; Wang, Xin; Zhang, Youdi; Dong, Wei; Zhang, Xindong; Liu, Caixia; Ruan, Shengping; Chen, Weiyou
2015-01-01
A bandwidth reconfigurable microwave photonic filter is proposed and numerically analyzed employing Brillouin gain spectrum narrowing and broadening. The stimulated Brillouin scattering (SBS) process is used to convert the phase modulation to intensity modulation to generate filter passband. Due to the fact that the passband is formed by mapping the Brillouin gain spectrum, bandwidth reconfiguration can be implemented by changing Brillouin gain linewidth. In this paper, both bandwidth reduction and increase are included in a single system and the details of gain spectrum narrowing and broadening are demonstrated. Theoretically, nearly 60% bandwidth reduction and hundreds times of bandwidth increase are achieved as compared to the case without gain spectrum process.
Model calculation of the charge transfer in low-energy He{sup +} scattering from metallic surfaces
Energy Technology Data Exchange (ETDEWEB)
Garcia, E.A. [Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, CC91, 3000, Santa Fe (Argentina); Bolcatto, P.G. [Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, CC91, 3000, Santa Fe (Argentina)]|[Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829, 3000, Santa Fe (Argentina); Goldberg, E.C. [Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, CC91, 3000, Santa Fe (Argentina)
1995-12-15
Charge-transfer mechanisms in low-energy helium-scattering spectroscopy are analyzed by using an Anderson-like description of the time-dependent collisional process, which allows us to include several electronic bands of extended and localized nature in the solid. The Hamiltonian parameters are obtained from a Hartree-Fock self-consistent-field calculation of the He-target atom dimeric system. We examine in particular cases such as Ca and Ga linear chain substrates. We found that at velocities large enough, the localized state in the solid contributes to the He{sup +} neutralization, showing the characteristic oscillatory behavior of the nonadiabatic charge exchange between localized states, in agreement with other calculations. In the range of low velocities we found that if the hybridization between the He orbital and the localized states in the solid is able to produce the formation of an antibonding state having a predominant weight of the He-1{ital s} orbital, this promotes the charge exchange between the Helium and the extended bandstates of the solid.
Study of scattering patterns and subwavelength scale imaging based on finite-sized metamaterials
Zhang, Yuan; Chuang, Yi-Chen; Schenk, John O.; Fiddy, Michael A.
2012-04-01
A metamaterial slab, used as a superlens in a subwavelength imaging system, is frequently assumed homogeneous. It is the bulk properties of the metamaterial which are responsible for the resolution of the transferred information in the image domain, as a result of high transverse wave-vector coupling. However, how in a discretized metamaterial, individual meta-atoms (i.e., the meta-elements composing a negative index metamaterial slab) contribute to the imaging process is still actively studied. The main aim of this paper is to investigate the consequences of using only a few meta-atoms as a negative index slab-equivalent for subwavelength scale imaging. We make a specific choice for a meta-atom and investigate its resonant scattering patterns. We report on how knowledge of these 3D scattering patterns provides a means to understand the transfer of high spatial frequencies and assist with the design an improved negative index slab.
Optical fiber humidity sensor based on evanescent-wave scattering.
Xu, Lina; Fanguy, Joseph C; Soni, Krunal; Tao, Shiquan
2004-06-01
The phenomenon of evanescent-wave scattering (EWS) is used to design an optical-fiber humidity sensor. Porous solgel silica (PSGS) coated on the surface of a silica optical-fiber core scatters evanescent waves that penetrate the coating layer. Water molecules in the gas phase surrounding the optical fiber can be absorbed into the inner surface of the pores of the porous silica. The absorbed water molecules form a thin layer of liquid water on the inner surface of the porous silica and enhance the EWS. The amount of water absorbed into the PSGS coating is in dynamic equilibrium with the water-vapor pressure in the gas phase. Therefore the humidity in the air can be quantitatively determined with fiber-optic EWS caused by the PSGS coating. The humidity sensor reported here is fast in response, reversible, and has a wide dynamic range. The possible interference caused by EWS to an optical-fiber gas sensor with a reagent-doped PSGS coating as a transducer is also discussed. PMID:15209243
Novel Boron-10-based detectors for Neutron Scattering Science
Piscitelli, Francesco
2015-01-01
Nowadays neutron scattering science is increasing its instrumental power. Most of the neutron sources in the world are pushing the development of their technologies to be more performing. The neutron scattering development is also pushed by the European Spallation Source (ESS) in Sweden, a neutron facility which has just started construction. Concerning small area detectors (1m^2), the 3He technology, which is today cutting edge, is reaching fundamental limits in its development. Counting rate capability, spatial resolution and cost-e?ectiveness, are only a few examples of the features that must be improved to ful?fill the new requirements. On the other hand, 3He technology could still satisfy the detector requirements for large area applications (50m^2), however, because of the present 3He shortage that the world is experiencing, this is not practical anymore. The recent detector advances (the Multi-Grid and the Multi-Blade prototypes) developed in the framework of the collaboration between the Institut Laue...
A small angle neutron scattering study of mica based glass-ceramics with applications in dentistry
International Nuclear Information System (INIS)
We are currently developing machinable and load-bearing mica-based glass-ceramics for use in restorative dental surgery. In this paper we present the results of an ambient temperature small angle neutron scattering (SANS) study of several such ceramics with chemical compositions chosen to optimise machinability and strength. The SANS spectra are all dominated by scattering from the crystalline-amorphous phase interface and exhibit Q-4 dependence (Porod scattering) indicating that, on a 100 A scale, the surface of the crystals is smooth
A small angle neutron scattering study of mica based glass-ceramics with applications in dentistry
Kilcoyne, S. H.; Bentley, P. M.; Al-Jawad, M.; Bubb, N. L.; Al-Shammary, H. A. O.; Wood, D. J.
2004-07-01
We are currently developing machinable and load-bearing mica-based glass-ceramics for use in restorative dental surgery. In this paper we present the results of an ambient temperature small angle neutron scattering (SANS) study of several such ceramics with chemical compositions chosen to optimise machinability and strength. The SANS spectra are all dominated by scattering from the crystalline-amorphous phase interface and exhibit Q-4 dependence (Porod scattering) indicating that, on a 100Å scale, the surface of the crystals is smooth.
A small angle neutron scattering study of mica based glass-ceramics with applications in dentistry
Energy Technology Data Exchange (ETDEWEB)
Kilcoyne, S.H.; Bentley, P.M.; Al-Jawad, M.; Bubb, N.L.; Al-Shammary, H.A.O.; Wood, D.J
2004-07-15
We are currently developing machinable and load-bearing mica-based glass-ceramics for use in restorative dental surgery. In this paper we present the results of an ambient temperature small angle neutron scattering (SANS) study of several such ceramics with chemical compositions chosen to optimise machinability and strength. The SANS spectra are all dominated by scattering from the crystalline-amorphous phase interface and exhibit Q{sup -4} dependence (Porod scattering) indicating that, on a 100 A scale, the surface of the crystals is smooth.
Time-based ensemble scattering measurements in fuel sprays
International Nuclear Information System (INIS)
This paper reports that knowledge of droplet size in sprays is important for spray combustion, pesticide and herbicide spraying, spray cooling, fire sprinklers, and many other industrial applications. The importance of measuring and evaluating time-varying information in sprays can be critical to the performance of these spray systems. For example, gas turbine and rocket motor stability is dependent on suppression of combustor frequencies which alter the atomization characteristics of the spray. High-speed movies of the atomization process have shown that steady sprays are not uniform in time but can contain clusters of droplets. Droplet clustering may have significant ramifications in combustion applications for soot production. Another time-dependent phenomenon observed in airblast-atomized sprays is a rapid change is spray angle known as fluttering. To study such phenomena, an ensemble light scattering technique was used to obtain time-resolved information on droplet mean size and number density in sprays where similar temporal features have been observed
Multiphase flow parameter estimation based on laser scattering
Vendruscolo, Tiago P.; Fischer, Robert; Martelli, Cicero; Rodrigues, Rômulo L. P.; Morales, Rigoberto E. M.; da Silva, Marco J.
2015-07-01
The flow of multiple constituents inside a pipe or vessel, known as multiphase flow, is commonly found in many industry branches. The measurement of the individual flow rates in such flow is still a challenge, which usually requires a combination of several sensor types. However, in many applications, especially in industrial process control, it is not necessary to know the absolute flow rate of the respective phases, but rather to continuously monitor flow conditions in order to quickly detect deviations from the desired parameters. Here we show how a simple and low-cost sensor design can achieve this, by using machine-learning techniques to distinguishing the characteristic patterns of oblique laser light scattered at the phase interfaces. The sensor is capable of estimating individual phase fluxes (as well as their changes) in multiphase flows and may be applied to safety applications due to its quick response time.
Multiphase flow parameter estimation based on laser scattering
International Nuclear Information System (INIS)
The flow of multiple constituents inside a pipe or vessel, known as multiphase flow, is commonly found in many industry branches. The measurement of the individual flow rates in such flow is still a challenge, which usually requires a combination of several sensor types. However, in many applications, especially in industrial process control, it is not necessary to know the absolute flow rate of the respective phases, but rather to continuously monitor flow conditions in order to quickly detect deviations from the desired parameters. Here we show how a simple and low-cost sensor design can achieve this, by using machine-learning techniques to distinguishing the characteristic patterns of oblique laser light scattered at the phase interfaces. The sensor is capable of estimating individual phase fluxes (as well as their changes) in multiphase flows and may be applied to safety applications due to its quick response time. (paper)
Recent Progress in Brillouin Scattering Based Fiber Sensors
Directory of Open Access Journals (Sweden)
Liang Chen
2011-04-01
Full Text Available Brillouin scattering in optical fiber describes the interaction of an electro-magnetic field (photon with a characteristic density variation of the fiber. When the electric field amplitude of an optical beam (so-called pump wave, and another wave is introduced at the downshifted Brillouin frequency (namely Stokes wave, the beating between the pump and Stokes waves creates a modified density change via the electrostriction effect, resulting in so-called the stimulated Brillouin scattering. The density variation is associated with a mechanical acoustic wave; and it may be affected by local temperature, strain, and vibration which induce changes in the fiber effective refractive index and sound velocity. Through the measurement of the static or dynamic changes in Brillouin frequency along the fiber one can realize a distributed fiber sensor for local temperature, strain and vibration over tens or hundreds of kilometers. This paper reviews the progress on improving sensing performance parameters like spatial resolution, sensing length limitation and simultaneous temperature and strain measurement. These kinds of sensors can be used in civil structural monitoring of pipelines, bridges, dams, and railroads for disaster prevention. Analogous to the static Bragg grating, one can write a moving Brillouin grating in fibers, with the lifetime of the acoustic wave. The length of the Brillouin grating can be controlled by the writing pulses at any position in fibers. Such gratings can be used to measure changes in birefringence, which is an important parameter in fiber communications. Applications for this kind of sensor can be found in aerospace, material processing and fine structures.
Scattering correction based on regularization de-convolution for Cone-Beam CT
Xie, Shi-peng
2016-01-01
In Cone-Beam CT (CBCT) imaging systems, the scattering phenomenon has a significant impact on the reconstructed image and is a long-lasting research topic on CBCT. In this paper, we propose a simple, novel and fast approach for mitigating scatter artifacts and increasing the image contrast in CBCT, belonging to the category of convolution-based method in which the projected data is de-convolved with a convolution kernel. A key step in this method is how to determine the convolution kernel. Compared with existing methods, the estimation of convolution kernel is based on bi-l1-l2-norm regularization imposed on both the intermediate the known scatter contaminated projection images and the convolution kernel. Our approach can reduce the scatter artifacts from 12.930 to 2.133.
Anomalous enhancement in the optical scattered radiation in magnetite base ferrofluid
International Nuclear Information System (INIS)
Analysis and measurements of optical transmission of laser beam through ferrofluid have shown anomalous optical behavior of kerosene-based ferrofluid under the presence or absence of magnetic field. The optical transmission is polarization dependent and the observed pattern is attributed to dipole scattering. The spectral characteristic of ferrofluid indicates the dipole scattering and superparamagnetic behavior of the particles. The anomaly in the system is correlated with the magnetic, size distribution and other spectral measurements
Aggregation in non-ionic water-based ferrofluids by small-angle neutron scattering
International Nuclear Information System (INIS)
Small-angle neutron scattering was applied for detecting structural changes in non-ionic water-based ferrofluids when they were put in a magnetic field and then, after some period, returned to normal conditions. The observed changes in the scattering reflect the formation of elongated chain-like complexes stimulated by the magnetic field. The growth of these complexes takes place long after the magnetic field is turned off
Aggregation in non-ionic water-based ferrofluids by small-angle neutron scattering
Energy Technology Data Exchange (ETDEWEB)
Aksenov, V.L.; Avdeev, M.V. E-mail: avd@nf.jiinr.ru; Balasoiu, M.; Bica, D.; Rosta, L.; Toeroek, Gy.; Vekas, L
2003-03-01
Small-angle neutron scattering was applied for detecting structural changes in non-ionic water-based ferrofluids when they were put in a magnetic field and then, after some period, returned to normal conditions. The observed changes in the scattering reflect the formation of elongated chain-like complexes stimulated by the magnetic field. The growth of these complexes takes place long after the magnetic field is turned off.
Femtosecond direct observation of charge transfer between bases in DNA
Wan, Chaozhi; Fiebig, Torsten; Schiemann, Olav; Barton, Jacqueline K.; Zewail, Ahmed H.
2000-01-01
Charge transfer in supramolecular assemblies of DNA is unique because of the notion that the π-stacked bases within the duplex may mediate the transport, possibly leading to damage and/or repair. The phenomenon of transport through π-stacked arrays over a long distance has an analogy to conduction in molecular electronics, but the mechanism still needs to be determined. To decipher the elementary steps and the mechanism, one has to directly measure the dynamics in ...
A molecularly based theory for electron transfer reorganization energy
International Nuclear Information System (INIS)
Using field-theoretic techniques, we develop a molecularly based dipolar self-consistent-field theory (DSCFT) for charge solvation in pure solvents under equilibrium and nonequilibrium conditions and apply it to the reorganization energy of electron transfer reactions. The DSCFT uses a set of molecular parameters, such as the solvent molecule’s permanent dipole moment and polarizability, thus avoiding approximations that are inherent in treating the solvent as a linear dielectric medium. A simple, analytical expression for the free energy is obtained in terms of the equilibrium and nonequilibrium electrostatic potential profiles and electric susceptibilities, which are obtained by solving a set of self-consistent equations. With no adjustable parameters, the DSCFT predicts activation energies and reorganization energies in good agreement with previous experiments and calculations for the electron transfer between metallic ions. Because the DSCFT is able to describe the properties of the solvent in the immediate vicinity of the charges, it is unnecessary to distinguish between the inner-sphere and outer-sphere solvent molecules in the calculation of the reorganization energy as in previous work. Furthermore, examining the nonequilibrium free energy surfaces of electron transfer, we find that the nonequilibrium free energy is well approximated by a double parabola for self-exchange reactions, but the curvature of the nonequilibrium free energy surface depends on the charges of the electron-transferring species, contrary to the prediction by the linear dielectric theory
Speckle-based measurement of the light scattering by red blood cells in vivo
Fine, I.; Kaminsky, A.
2011-03-01
Optical spectroscopy approach, using non-coherent light sources, has become an important tool for non-invasive analysis in vivo. It is based on the assumption that biochemical characteristics of biological system can be determined through the optical coefficients of blood and tissue particles. Thus, in the framework of this approach, the major concern is to express the obtained optical signals in terms the optical coefficients of the single particle of blood or tissue. However, since the light propagation in tissue is dominated by the multiple-scattering component, a direct measurement of single scattering characteristics turns to be a very difficult task. Practically, only the relative changes of absorption and scattering coefficients are measured. We suggested to adopt the dynamic light scattering (DLS) or speckle technique for the determination of the light scattering coefficients of the red blood cells under stasis conditions in vivo. We assumed that under zero flow conditions the RBC movement is driven mostly by the Brownian motion. It was shown, that under appropriate measurement geometry, the measured optical signal can be decomposed into a few major components. The most dominant components are ascribed to the single backscattering and forward scattering coefficients of the red blood cells. In-vitro and in vivo experimental tests have shown a good correspondence between the theoretically estimated and experientially measured results. The obtained results indicate that the DLS technique can be adopted for the determination of blood particles scattering characteristics in addition to the movement and effective viscosity parameters measurement in vivo.
Robust primary modulation-based scatter estimation for cone-beam CT
Energy Technology Data Exchange (ETDEWEB)
Ritschl, Ludwig, E-mail: ludwig.ritschl@ziehm-eu.com [Ziehm Imaging, Nürnberg 90451 (Germany); Fahrig, Rebecca [Radiological Science Laboratory, Stanford University, 1201 Welch Road Palo Alto, Stanford, California 94304 (United States); Knaup, Michael; Maier, Joscha; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120 (Germany)
2015-01-15
Purpose: Scattered radiation is one of the major problems facing image quality in flat detector cone-beam computed tomography (CBCT). Previously, a new scatter estimation and correction method using primary beam modulation has been proposed. The original image processing technique used a frequency-domain-based analysis, which proved to be sensitive to the accuracy of the modulator pattern both spatially and in amplitude as well as to the frequency of the modulation pattern. In addition, it cannot account for penumbra effects that occur, for example, due to the finite focal spot size and the scatter estimate can be degraded by high-frequency components of the primary image. Methods: In this paper, the authors present a new way to estimate the scatter using primary modulation. It is less sensitive to modulator nonidealities and most importantly can handle arbitrary modulator shapes and changes in modulator attenuation. The main idea is that the scatter estimation can be expressed as an optimization problem, which yields a separation of the scatter and the primary image. The method is evaluated using simulated and experimental CBCT data. The scattering properties of the modulator itself are analyzed using a Monte Carlo simulation. Results: All reconstructions show strong improvements of image quality. To quantify the results, all images are compared to reference images (ideal simulations and collimated scans). Conclusions: The proposed modulator-based scatter reduction algorithm may open the field of flat detector-based imaging to become a quantitative modality. This may have significant impact on C-arm imaging and on image-guided radiation therapy.
Czech Academy of Sciences Publication Activity Database
Štěpán, Jiří; Trujillo Bueno, J.; Leenaarts, J.; Carlsson, M.
2015-01-01
Roč. 803, č. 2 (2015), 65/1-65/15. ISSN 0004-637X R&D Projects: GA ČR GPP209/12/P741 Grant ostatní: EU(XE) COST action MP1104 Institutional support: RVO:67985815 Keywords : polarization * radiative transfer * scattering Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.993, year: 2014
Energy Technology Data Exchange (ETDEWEB)
Baba, Justin S [ORNL; John, Dwayne O [ORNL; Koju, Vijay [ORNL
2015-01-01
The propagation of light in turbid media is an active area of research with relevance to numerous investigational fields, e.g., biomedical diagnostics and therapeutics. The statistical random-walk nature of photon propagation through turbid media is ideal for computational based modeling and simulation. Ready access to super computing resources provide a means for attaining brute force solutions to stochastic light-matter interactions entailing scattering by facilitating timely propagation of sufficient (>10million) photons while tracking characteristic parameters based on the incorporated physics of the problem. One such model that works well for isotropic but fails for anisotropic scatter, which is the case for many biomedical sample scattering problems, is the diffusion approximation. In this report, we address this by utilizing Berry phase (BP) evolution as a means for capturing anisotropic scattering characteristics of samples in the preceding depth where the diffusion approximation fails. We extend the polarization sensitive Monte Carlo method of Ramella-Roman, et al.,1 to include the computationally intensive tracking of photon trajectory in addition to polarization state at every scattering event. To speed-up the computations, which entail the appropriate rotations of reference frames, the code was parallelized using OpenMP. The results presented reveal that BP is strongly correlated to the photon penetration depth, thus potentiating the possibility of polarimetric depth resolved characterization of highly scattering samples, e.g., biological tissues.
Carbon nanohorn-based nanofluids: characterization of the spectral scattering albedo.
Mercatelli, Luca; Sani, Elisa; Giannini, Annalisa; Di Ninni, Paola; Martelli, Fabrizio; Zaccanti, Giovanni
2012-01-01
The full characterization of the optical properties of nanofluids consisting of single-wall carbon nanohorns of different morphologies in aqueous suspensions is carried out using a novel spectrophotometric technique. Information on the nanofluid scattering and absorption spectral characteristics is obtained by analyzing the data within the single scattering theory and validating the method by comparison with previous monochromatic measurements performed with a different technique. The high absorption coefficient measured joint to the very low scattering albedo opens promising application perspectives for single-wall carbon nanohorn-based fluid or solid suspensions. The proposed approximate approach can be extended also to other low-scattering turbid media.PACS: 78.35.+c Brillouin and Rayleigh scattering, other light scattering; 78.40.Ri absorption and reflection spectra, fullerenes and related materials; 81.05.U- carbon/carbon-based materials; 78.67.Bf optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures, nanocrystals, nanoparticles, and nanoclusters. PMID:22297089
Micro-Doppler Effect of Extended Streamlined Targets Based on Sliding Scattering Centre Model
Directory of Open Access Journals (Sweden)
Bo Tang
2016-06-01
Full Text Available The scattering center of extended streamlined targets can slide when the direction of radiation is changed. The sliding scattering center has influence on the micro-Doppler effect of micro-motion of the extended streamlined target. This paper focused on the micro-Doppler of the extended streamlined target for the bistatic radar. Based on the analysis, the analytical expressions of the micro-Doppler of coning motion with sliding scattering center model were given for bistatic radar. And the results were validated by the simulated results of the scattering field based on the full-wave method of the electromagnetic computation. The results showed that the sliding of the scattering center can make the micro-Doppler be less and distorted, and the influence of the sliding is different for two different types of the sliding scattering centers: sliding on the surface and sliding on the bottom circle. The analytical expressions of the micro-Doppler are helpful to analyze the time-frequency presentations (TFR of the coning motion of the extended streamlined target and to estimate the parameters of the target.
The Electron Scattering Data Base - Is it Fit for Purpose ?
International Nuclear Information System (INIS)
Electron induced reactions in both the gaseous and condensed phases initiate and drive many of the basic physical and chemical processes in science and technology with applications from industrial plasmas to radiation damage in living tissue. For example, in contrast to previous hypotheses, collisions of very low energy secondary electrons with the components of DNA molecules (or to the water around them) has been shown to be a crucial process in inducing radiation damage in the DNA of living systems. Understanding electron interactions with larger biomolecules is therefore providing new insights to radiation damage and thence the development of new, alternative radiotherapies. In the technological field electron induced reactions underpin most of the multibillion dollar modern semiconductor industry since it is those reactive fragments produced by electron impact of etchant gases that react directly with the silicon substrate. Studies on electron scattering from molecules capable of improving the etch rate of surfaces are leading to development of new (environmentally cleaner) plasma technologies. Electron induced processes are also of extraordinary importance for determination of structure and chemical reactivity of species adsorbed on surfaces. Such research and technology is intricately linked to our knowledge of the key interactions between electosn and atoms and molecules and thus we require a database for characterizing electron interactions with atomic and molecular species. However the compilation of the electron collsion data required is rarely a coherent, planned research programme instead it is a parasitic process. Indeed today it is rare for researchers to be funded to measure fundamental collision processes since these are no longer regarded in themselves as 'cutting edge' research rather the field has developed to explore more exotic phenomena such as cold atoms; nanotechnology and chemical control. The fundamental research community, the providers
Base fluid in improving heat transfer for EV car battery
Bin-Abdun, Nazih A.; Razlan, Zuradzman M.; Shahriman, A. B.; Wan, Khairunizam; Hazry, D.; Ahmed, S. Faiz; Adnan, Nazrul H.; Heng, R.; Kamarudin, H.; Zunaidi, I.
2015-05-01
This study examined the effects of base fluid (as coolants) channeling inside the heat exchanger in the process of the increase in thermal conductivity between EV car battery and the heat exchanger. The analysis showed that secondary cooling system by means of water has advantages in improving the heat transfer process and reducing the electric power loss on the form of thermal energy from batteries. This leads to the increase in the efficiency of the EV car battery, hence also positively reflecting the performance of the EV car. The present work, analysis is performed to assess the design and use of heat exchanger in increasing the performance efficiency of the EV car battery. This provides a preface to the use this design for nano-fluids which increase and improve from heat transfer.
New memory devices based on the proton transfer process
Wierzbowska, Małgorzata
2016-01-01
Memory devices operating due to the fast proton transfer (PT) process are proposed by the means of first-principles calculations. Writing information is performed using the electrostatic potential of scanning tunneling microscopy (STM). Reading information is based on the effect of the local magnetization induced at the zigzag graphene nanoribbon (Z-GNR) edge—saturated with oxygen or the hydroxy group—and can be realized with the use of giant magnetoresistance (GMR), a magnetic tunnel junction or spin-transfer torque devices. The energetic barriers for the hop forward and backward processes can be tuned by the distance and potential of the STM tip; this thus enables us to tailor the non-volatile logic states. The proposed system enables very dense packing of the logic cells and could be used in random access and flash memory devices.
New memory devices based on the proton transfer process.
Wierzbowska, Małgorzata
2016-01-01
Memory devices operating due to the fast proton transfer (PT) process are proposed by the means of first-principles calculations. Writing information is performed using the electrostatic potential of scanning tunneling microscopy (STM). Reading information is based on the effect of the local magnetization induced at the zigzag graphene nanoribbon (Z-GNR) edge-saturated with oxygen or the hydroxy group-and can be realized with the use of giant magnetoresistance (GMR), a magnetic tunnel junction or spin-transfer torque devices. The energetic barriers for the hop forward and backward processes can be tuned by the distance and potential of the STM tip; this thus enables us to tailor the non-volatile logic states. The proposed system enables very dense packing of the logic cells and could be used in random access and flash memory devices. PMID:26596910
Liu, Yan; Shen, Yuecheng; Ma, Cheng; Shi, Junhui; Wang, Lihong V.
2016-06-01
Ultrasound-modulated optical tomography (UOT) images optical contrast deep inside scattering media. Heterodyne holography based UOT is a promising technique that uses a camera for parallel speckle detection. In previous works, the speed of data acquisition was limited by the low frame rates of conventional cameras. In addition, when the signal-to-background ratio was low, these cameras wasted most of their bits representing an informationless background, resulting in extremely low efficiencies in the use of bits. Here, using a lock-in camera, we increase the bit efficiency and reduce the data transfer load by digitizing only the signal after rejecting the background. Moreover, compared with the conventional four-frame based amplitude measurement method, our single-frame method is more immune to speckle decorrelation. Using lock-in camera based UOT with an integration time of 286 μs, we imaged an absorptive object buried inside a dynamic scattering medium exhibiting a speckle correlation time ( τc ) as short as 26 μs. Since our method can tolerate speckle decorrelation faster than that found in living biological tissue ( τc ˜ 100-1000 μs), it is promising for in vivo deep tissue non-invasive imaging.
Modified time reversal imaging of a closed crack based on nonlinear scattering
Blanloeuil, Philippe; Rose, L. R. Francis; Guinto, Jed A.; Veidt, Martin; Wang, Chun H.
2016-04-01
A recent variant of time reversal imaging is used to detect and characterize a closed crack based on both the fundamental and the second harmonic components of the scattered waves in the presence of Contact Acoustic Nonlinearity at the crack interface. A Finite Element model, which includes unilateral contact with Coulomb friction to account for contact between the crack faces, is used to compute the scattered field resulting from the interaction between incident longitudinal plane waves and the crack. The knowledge of the scattering for multiple incident angles constitutes the input for the imaging algorithm. Good reconstruction of the crack is obtained from both harmonic sources, and second harmonic based images also enables one to identify the location of the second harmonic sources along the crack. This first imaging based on the second harmonic also offers potential baseline free detection of closed cracks.
Resonant energy transfer based biosensor for detection of multivalent proteins.
Energy Technology Data Exchange (ETDEWEB)
Song, X. (Xuedong); Swanson, Basil I.
2001-01-01
We have developed a new fluorescence-based biosensor for sensitive detection of species involved in a multivslent interaction. The biosensor system utilizes specific interactions between proteins and cell surface receptors, which trigger a receptor aggregation process. Distance-dependent fluorescence self-quenching and resonant energy transfer mechanisms were coupled with a multivalent interaction to probe the receptor aggregation process, providing a sensitive and specific signal transduction method for such a binding event. The fluorescence change induced by the aggregation process can be monitored by different instrument platforms, e.g. fluorimetry and flow cytometry. In this article, a sensitive detection of pentavalent cholera toxin which recognizes ganglioside GM1 has been demonstrated through the resonant energy transfer scheme, which can achieve a double color change simultaneously. A detection sensitivity as high as 10 pM has been achieved within a few minutes (c.a. 5 minutes). The simultaneous double color change (an increase of acceptor fluorescence and a decrease of donor fluorescence intensity) of two similar fluorescent probes provides particularly high detection reliability owing to the fact that they act as each other's internal reference. Any external perturbation such as environmental temperature change causes no significant change in signal generation. Besides the application for biological sensing, the method also provides a useful tool for investigation of kinetics and thermodynamics of a multivalent interaction. Keywords: Biosensor, Fluorescence resonant energy transfer, Multivalent interaction, Cholera Toxin, Ganglioside GM1, Signal Transduction
Gene ontology based transfer learning for protein subcellular localization
Directory of Open Access Journals (Sweden)
Zhou Shuigeng
2011-02-01
Full Text Available Abstract Background Prediction of protein subcellular localization generally involves many complex factors, and using only one or two aspects of data information may not tell the true story. For this reason, some recent predictive models are deliberately designed to integrate multiple heterogeneous data sources for exploiting multi-aspect protein feature information. Gene ontology, hereinafter referred to as GO, uses a controlled vocabulary to depict biological molecules or gene products in terms of biological process, molecular function and cellular component. With the rapid expansion of annotated protein sequences, gene ontology has become a general protein feature that can be used to construct predictive models in computational biology. Existing models generally either concatenated the GO terms into a flat binary vector or applied majority-vote based ensemble learning for protein subcellular localization, both of which can not estimate the individual discriminative abilities of the three aspects of gene ontology. Results In this paper, we propose a Gene Ontology Based Transfer Learning Model (GO-TLM for large-scale protein subcellular localization. The model transfers the signature-based homologous GO terms to the target proteins, and further constructs a reliable learning system to reduce the adverse affect of the potential false GO terms that are resulted from evolutionary divergence. We derive three GO kernels from the three aspects of gene ontology to measure the GO similarity of two proteins, and derive two other spectrum kernels to measure the similarity of two protein sequences. We use simple non-parametric cross validation to explicitly weigh the discriminative abilities of the five kernels, such that the time & space computational complexities are greatly reduced when compared to the complicated semi-definite programming and semi-indefinite linear programming. The five kernels are then linearly merged into one single kernel for
Xavier Sala-i-Martin
1992-01-01
In this paper I develop a positive theory of intergenerational transfers. I argue that transfers are a means to induce retirement. that is, to buy the elderly out of the labor force. The reason why societies choose to do such a thing is that aggregate output is higher if the elderly do not work. I model this idea through positive externalities in the average stock of human capital: because skills depreciate with age. one implication of these externalities is that the elderly have a negative e...
Directory of Open Access Journals (Sweden)
Zi Ye
2012-10-01
Full Text Available Measuring particle size distribution through calculating light scattering intensity is a typical inverse problem. This paper builds an inverse mathematical model based on Mie scattering, deduces the inversion formulas for particle size, and calculates the relative coefficients through programming with built-in functions in MATLAB. In order to improve the accuracy and noise immunity of particle size distribution measurement, the development of stochastic inversion algorithm: an inverse problem model based on Markov chain algorithm is proposed. Results of numerical simulation are added acceptable noise indicate that the algorithm of Markov chain has strong noise immunity and can meet the requirements of on-line measurement.
Technology transfer package on seismic base isolation - Volume III
Energy Technology Data Exchange (ETDEWEB)
NONE
1995-02-14
This Technology Transfer Package provides some detailed information for the U.S. Department of Energy (DOE) and its contractors about seismic base isolation. Intended users of this three-volume package are DOE Design and Safety Engineers as well as DOE Facility Managers who are responsible for reducing the effects of natural phenomena hazards (NPH), specifically earthquakes, on their facilities. The package was developed as part of DOE's efforts to study and implement techniques for protecting lives and property from the effects of natural phenomena and to support the International Decade for Natural Disaster Reduction. Volume III contains supporting materials not included in Volumes I and II.
A preliminary study of breast cancer diagnosis using laboratory based small angle x-ray scattering
International Nuclear Information System (INIS)
Breast tissue collected from tumour samples and normal tissue from bi-lateral mastectomy procedures were examined using small angle x-ray scattering. Previous work has indicated that breast tissue disease diagnosis could be performed using small angle x-ray scattering (SAXS) from a synchrotron radiation source. The technique would be more useful to health services if it could be made to work using a conventional x-ray source. Consistent and reliable differences in x-ray scatter distributions were observed between samples from normal and tumour tissue samples using the laboratory based 'SAXSess' system. Albeit from a small number of samples, a sensitivity of 100% was obtained. This result encourages us to pursue the implementation of SAXS as a laboratory based diagnosis technique
A preliminary study of breast cancer diagnosis using laboratory based small angle x-ray scattering
Energy Technology Data Exchange (ETDEWEB)
Round, A R [Daresbury Laboratories, Warrington, WA4 4AD (United Kingdom); Wilkinson, S J [Daresbury Laboratories, Warrington, WA4 4AD (United Kingdom); Hall, C J [Daresbury Laboratories, Warrington, WA4 4AD (United Kingdom); Rogers, K D [Department of Materials and Medical Sciences, Cranfield University, Swindon, SN6 8LA (United Kingdom); Glatter, O [Department of Chemistry, University of Graz (Austria); Wess, T [School of Optometry and Vision Sciences, Cardiff University, Cardiff CF10 3NB, Wales (United Kingdom); Ellis, I O [Nottingham City Hospital, Nottingham (United Kingdom)
2005-09-07
Breast tissue collected from tumour samples and normal tissue from bi-lateral mastectomy procedures were examined using small angle x-ray scattering. Previous work has indicated that breast tissue disease diagnosis could be performed using small angle x-ray scattering (SAXS) from a synchrotron radiation source. The technique would be more useful to health services if it could be made to work using a conventional x-ray source. Consistent and reliable differences in x-ray scatter distributions were observed between samples from normal and tumour tissue samples using the laboratory based 'SAXSess' system. Albeit from a small number of samples, a sensitivity of 100% was obtained. This result encourages us to pursue the implementation of SAXS as a laboratory based diagnosis technique.
Method research of high Z materials detection based on high energy X-ray scattering
International Nuclear Information System (INIS)
In order to detect nuclear materials the study of the atomic number (Z) identification method based on scattering spectrum analysis and high Z characteristic of special nuclear materials was presented. The method can identify materials by detecting and analyzing positron annihilation photons, bremsstrahlung photons and Compton scattered photons produced by the interaction between X-ray and matter. The results of Monte Carlo simulation show that the method can discriminate Z effectively, especially for high Z materials. An experimental facility based on 7 MeV linac was set up for feasibility study and scattering spectra were observed with a LaBr3 (Ce) detector. Preliminary results verify that high Z materials can be discriminated successfully. (authors)
Lee, Seungah; Park, Guenyoung; Chakkarapani, Suresh Kumar; Kang, Seong Ho
2015-01-15
Novel, fluorescence-free detection of biomolecules on nanobiochips was investigated based on plasmonic nanometal scattering in the evanescent field layer (EFL) using total internal reflection scattering (TIRS) microscopy. The plasmonic scattering of nanometals bonded to biomolecules was observed at different wavelengths by an electromagnetic field in the EFL. The changes in the scattering of nanometals on the gold-nanopatterned chip in response to the immunoreaction between silver nanoparticles and antibodies allowed fluorescence-free detection of biomolecules on the nanobiochips. Under optimized conditions, the TIRS immunoassay chip detected different amounts of immobilized antigen, i.e., human cardiac troponin I. The sandwich immuno-reaction was quantitatively analyzed in the dynamic range of 720 zM-167 fM. The limit of detection (S/N=4) was 600 zM, which was ~140 times lower than limits obtained by previous total internal reflection fluorescence and dark field methods. These results demonstrate the possibility for a fluorescence-free biochip nanoimmunoassay based on the scattering of nanometals in the EFL. PMID:25128624
Analysis of error in soot characterization using scattering-based techniques
Institute of Scientific and Technical Information of China (English)
Lin Ma
2011-01-01
The increasing concern of the health and environmental effects of ultrafine soot particles emitted by modern combustion devices calls for new techniques to monitor such particles. Techniques based on light scattering represent one possible monitoring method. In this study, numerical simulations were conducted to examine the errors involved in soot characterization using light scattering techniques.Specifically, this study focused on examining the error caused by the approximate fractal scattering models based on the Rayleigh-Deybe-Gans theory (the RDG-FA model). When the angular scattering properties were used to retrieve parameters of soot aggregates (the radius of gyration and the fractal dimension), the RDG-FA method was observed to cause a relative error of ～10％ for a representative set of soot parameters. The effects of measurement uncertainties were also investigated. Our results revealed the pattern of the errors: the errors consisted of a relatively constant baseline error caused by the RDG-FA approximation and an error increasing with the measurement uncertainties. These results are expected to be useful in the analysis and interpretation of experimental data, and also in the determination of the accuracy and applicable range of scattering techniques.
A Network Based Methodology to Reveal Patterns in Knowledge Transfer
Directory of Open Access Journals (Sweden)
Orlando López-Cruz
2015-12-01
Full Text Available This paper motivates, presents and demonstrates in use a methodology based in complex network analysis to support research aimed at identification of sources in the process of knowledge transfer at the interorganizational level. The importance of this methodology is that it states a unified model to reveal knowledge sharing patterns and to compare results from multiple researches on data from different periods of time and different sectors of the economy. This methodology does not address the underlying statistical processes. To do this, national statistics departments (NSD provide documents and tools at their websites. But this proposal provides a guide to model information inferences gathered from data processing revealing links between sources and recipients of knowledge being transferred and that the recipient detects as main source to new knowledge creation. Some national statistics departments set as objective for these surveys the characterization of innovation dynamics in firms and to analyze the use of public support instruments. From this characterization scholars conduct different researches. Measures of dimensions of the network composed by manufacturing firms and other organizations conform the base to inquiry the structure that emerges from taking ideas from other organizations to incept innovations. These two sets of data are actors of a two- mode-network. The link between two actors (network nodes, one acting as the source of the idea. The second one acting as the destination comes from organizations or events organized by organizations that “provide” ideas to other group of firms. The resulting demonstrated design satisfies the objective of being a methodological model to identify sources in knowledge transfer of knowledge effectively used in innovation.
Ionov, Stanislav I.; LaVilla, Michael E.; Bernstein, Richard B.
1990-11-01
Time-of-flight distributions of beams of hexapole-oriented CHF3 and t-BuCl molecules scattered from a graphite (0001) surface have been measured for parallel vs antiparallel incident orientations of the molecular dipole with respect to the surface normal, over a range of surface temperatures 170≤Ts≤730 K. The observed difference in arrival times, Δtexp, for opposite initial orientations depends strongly on the degree of orientation of the incident molecules. In the analysis of the Δtexp data, we make use of the two-component model, which assumes that the scattered beams are composed of directly scattered and trapped/desorbed molecules. It is shown that in the common case of short residence times for the trapped molecules, the difference in arrival times for the directly scattered molecules, Δtdir, can be ascertained from the measured Δtexp. The magnitudes of the calculated Δtdir correspond to a strong orientation dependence in the translational energy transfer accompanying the direct scattering of CHF3 and t-BuCl by graphite (0001). The final translational energy of directly scattered molecules E' is found to be smaller for the collision of the H ``end'' of fluoroform with the graphite surface; for t-BuCl, E' is smaller for the Cl ``end'' collision. These are the orientations that also give rise to higher trapping probability. In the course of the present study, the residence times of t-BuCl on graphite (0001) have been measured over the surface temperature range 170
4.2 GeV α-12C Elastic Scattering Based on α-Particle Model
Institute of Scientific and Technical Information of China (English)
YANG Yong-Xu; LU Xiao; LI Qing-Run
2008-01-01
Based on the a-particle model of 12C nucleus, the differential cross sections for α-12 C elastic scattering at incident energy of 4.2 GeV have been calculated within the framework of Glauber multiple scattering theory. The results show that the main features of the measured angular distribution of the cross sections can be reasonably described. The parameterizedα-α scattering amplitude, which is the basic input to construct the α-12C scattering Glauber amplitude in the a-particle model, is obtained by fitting the α-α scattering data.
Technology transfer package on seismic base isolation - Volume I
Energy Technology Data Exchange (ETDEWEB)
NONE
1995-02-14
This Technology Transfer Package provides some detailed information for the U.S. Department of Energy (DOE) and its contractors about seismic base isolation. Intended users of this three-volume package are DOE Design and Safety Engineers as well as DOE Facility Managers who are responsible for reducing the effects of natural phenomena hazards (NPH), specifically earthquakes, on their facilities. The package was developed as part of DOE's efforts to study and implement techniques for protecting lives and property from the effects of natural phenomena and to support the International Decade for Natural Disaster Reduction. Volume I contains the proceedings of the Workshop on Seismic Base Isolation for Department of Energy Facilities held in Marina Del Rey, California, May 13-15, 1992.
Technology transfer package on seismic base isolation - Volume II
Energy Technology Data Exchange (ETDEWEB)
NONE
1995-02-14
This Technology Transfer Package provides some detailed information for the U.S. Department of Energy (DOE) and its contractors about seismic base isolation. Intended users of this three-volume package are DOE Design and Safety Engineers as well as DOE Facility Managers who are responsible for reducing the effects of natural phenomena hazards (NPH), specifically earthquakes, on their facilities. The package was developed as part of DOE's efforts to study and implement techniques for protecting lives and property from the effects of natural phenomena and to support the International Decade for Natural Disaster Reduction. Volume II contains the proceedings for the Short Course on Seismic Base Isolation held in Berkeley, California, August 10-14, 1992.
Sancho J.; Chin S.; Sagues M.; Loayssa A.; Lloret J.; Gasulla I.; Sales S.; Thevenaz L.; Capmany J.
2010-01-01
Dynamic reconfiguration of a microwave photonic filter by tuning its basic delay based on stimulated Brillouin scattering-induced slow light and optical phase shift of the optical carrier is experimentally implemented. The measurements confirm that the free spectral range of the filter changes when a Brillouin pump is applied. These results demonstrate the potential of the separate carrier technique in microwave photonics applications.
Controlling Kondo-like Scattering at the SrTiO3-based Interfaces
Han, K.; Palina, N.; Zeng, S. W.; Huang, Z; Li, C.J.; Zhou, W. X.; D.-Y. Wan; Zhang, L. C.; Chi, X.; Guo, R; Chen, J. S.; Venkatesan, T.; Rusydi, A.; Ariando
2016-01-01
The observation of magnetic interaction at the interface between nonmagnetic oxides has attracted much attention in recent years. In this report, we show that the Kondo-like scattering at the SrTiO3-based conducting interface is enhanced by increasing the lattice mismatch and growth oxygen pressure P O2. For the 26-unit-cell LaAlO3/SrTiO3 (LAO/STO) interface with lattice mismatch being 3.0%, the Kondo-like scattering is observed when P O2 is beyond 1 mTorr. By contrast, when the lattice misma...
International Nuclear Information System (INIS)
In porous-silicon-based multilayered structures that exhibit the properties of one-dimensional photonic crystals, an increase in the photoluminescence and Raman scattering intensities is observed upon optical excitation at the wavelength 1.064 μm. When the excitation wavelength falls within the edge of the photonic band gap of the structures, a multiple increase (by a factor larger than 400) in the efficiency of Raman scattering is detected. The effect is attributed to partial localization of excitation light and, correspondingly, to the much longer time of interaction of light with the material in the structures.
International Nuclear Information System (INIS)
The curved ray-tracing method is extended to radiative transfer in the graded index medium with diffuse gray boundary conditions instead of black boundary conditions and the pseudo-source adding method is extended to the case of the linear-anisotropic scattering medium with graded index from non-scattering medium. Furthermore, the equivalence of the two methods is verified by formulation derivation. As exact analytical solutions, both the methods have high accuracy and fast computational speed. The predicted temperature distributions and dimensionless radiative heat flux at radiative equilibrium are determined by the proposed methods, and the numerical results are compared with the data in references. The results show that the present methods have a good accuracy. Influences of various combinations of refractive index and boundary emissivities on the temperature distributions and dimensionless radiative heat flux are also investigated.
[Correction Method of Atmospheric Scattering Effect Based on Three Spectrum Bands].
Ye, Han-han; Wang, Xian-hua; Jiang, Xin-hua; Bu, Ting-ting
2016-03-01
As a major error of CO2 retrieval, atmospheric scattering effect hampers the application of satellite products. Effect of aerosol and combined effect of aerosol and ground surface are important source of atmospheric scattering, so it needs comprehensive consideration of scattering effect from aerosol and ground surface. Based on the continuum, strong and weak absorption part of three spectrum bands O2-A, CO2 1.6 μm and 2.06 μm, information of aerosol and albedo was analyzed, and improved full physics retrieval method was proposed, which can retrieve aerosol and albedo simultaneously to correct the scattering effect. Simulation study on CO2 error caused by aerosol and ground surface albedo CO2 error by correction method was carried out. CO2 error caused by aerosol optical depth and ground surface albedo can reach up to 8%, and CO2 error caused by different types of aerosol can reach up to 10%, while these two types of error can be controlled within 1% and 2% separately by this correction method, which shows that the method can correct the scattering effect effectively. Through evaluation of the results, the potential of this method for high precision satellite data retrieval is obvious, meanwhile, some problems which need to be noticed in real application were also pointed out. PMID:27400493
International Nuclear Information System (INIS)
This letter proposes and demonstrates ultrasound-combined optical imaging in dense scattering media. A peroxyoxalate chemiluminescence system that includes fluorophores to chemically excite the pigment is stimulated by ultrasound irradiation with power of less than 0.14 W/cm2. Using focused ultrasound, the chemiluminescence is selectively spatially enhanced, which leads to imaging of the pigment when embedded in a light-scattering medium via scanning of the focal point. The ultrasonically enhanced intensity of the chemiluminescence depends on the base intensity of the chemiluminescence without the applied ultrasound irradiation, which thereby enables quantitative determination of the fluorophore concentration. The authors demonstrate the potential of this method to resolve chemiluminescent targets in a dense scattering medium that is comparable to biological tissue. An image was acquired of a chemiluminescent target that included indocyanine green as the fluorophore embedded at a depth of 20 mm in an Intralipid-10% 200 ml/l solution scattering medium (the reduced scattering coefficient was estimated to be approximately 1.3 mm−1), indicating the potential for expansion of this technique for use in biological applications
Energy Technology Data Exchange (ETDEWEB)
Kobayashi, Masaki, E-mail: masaki@tohtech.ac.jp; Kikuchi, Naoto; Sato, Akihiro [Department of Electronics and Intelligent Systems, Tohoku Institute of Technology, Sendai 982-8577 (Japan)
2015-01-12
This letter proposes and demonstrates ultrasound-combined optical imaging in dense scattering media. A peroxyoxalate chemiluminescence system that includes fluorophores to chemically excite the pigment is stimulated by ultrasound irradiation with power of less than 0.14 W/cm{sup 2}. Using focused ultrasound, the chemiluminescence is selectively spatially enhanced, which leads to imaging of the pigment when embedded in a light-scattering medium via scanning of the focal point. The ultrasonically enhanced intensity of the chemiluminescence depends on the base intensity of the chemiluminescence without the applied ultrasound irradiation, which thereby enables quantitative determination of the fluorophore concentration. The authors demonstrate the potential of this method to resolve chemiluminescent targets in a dense scattering medium that is comparable to biological tissue. An image was acquired of a chemiluminescent target that included indocyanine green as the fluorophore embedded at a depth of 20 mm in an Intralipid-10% 200 ml/l solution scattering medium (the reduced scattering coefficient was estimated to be approximately 1.3 mm{sup −1}), indicating the potential for expansion of this technique for use in biological applications.
A Compton scattering image reconstruction algorithm based on total variation minimization
Institute of Scientific and Technical Information of China (English)
Li Shou-Peng; Wang Lin-Yuan; Yan Bin; Li Lei; Liu Yong-Jun
2012-01-01
Compton scattering imaging is a novel radiation imaging method using scattered photons.Its main characteristics are detectors that do not have to be on the opposite side of the source,so avoiding the rotation process.The reconstruction problem of Compton scattering imaging is the inverse problem to solve electron densities from nonlinear equations,which is ill-posed.This means the solution exhibits instability and sensitivity to noise or erroneous measurements.Using the theory for reconstruction of sparse images,a reconstruction algorithm based on total variation minimization is proposed.The reconstruction problem is described as an optimization problem with nonlinear data-consistency constraint.The simulated results show that the proposed algorithm could reduce reconstruction error and improve image quality,especially when there are not enough measurements.
Superstructure scattering distribution based ship recognition in TerraSAR-X imagery
International Nuclear Information System (INIS)
Benefiting from the improved resolution and polarization information of SAR data, ship recognition has attracted much attention during the last decade. This paper considers the ship recognition in TerraSAR-X imagery. We propose a novel feature extraction algorithm, named Superstructure Scattering Distribution (SSD), by investigating the ship's superstructure and corresponding electromagnetic scattering mechanism. In SSD, we first segment the image areas that correspond to the scattering of ship's superstructure using segmentation and edge detection methods. Once the superstructure areas of ship in SAR imagery have been obtained, we then calculate a novel feature parameter to describe the distribution and shape complexity of the ship based on the fractal dimension and other shape complexity descriptors. Extensive experiments have been carried out on ship datasets collected from TerraSAR-X SAR imagery. The results validate that the SSD feature can achieve better performance together with other physical features
All-Optical Nanometric Switch based on the Directional Scattering of Semiconductor Nanoparticles
Garcia-Camara, Braulio; Cuadrado, Alexander; Urruchi, Virginia; Sanchez-Pena, Jose Manuel; Serna, Rosalia; Vergaz, Ricardo
2015-01-01
A structure based on a dimer of silicon nanoparticles, presenting directional scattering in the visible range, was studied as a new design of an all-optical switch. The combination of spherical nanoparticles satisfying, at the same incident wavelength, the zero-backward and the minimum-forward scattering conditions, can produce either a maximum or a minimum of the scattered field in the area between the nanoparticles. The modulation of the incident wavelength can be used as switching parameter, due to the sensitivity of these conditions to it. An optimization of the dimer setup, both in the distance between the nanoparticles and the incident wavelength, was numerically performed to obtain a maximum contrast. Also, near-field and far-field distributions of the electric field have been considered.
de Aguiar, Hilton B; Brasselet, Sophie
2016-01-01
Despite the tremendous progresses in wavefront control through or inside complex scattering media, several limitations prevent reaching practical feasibility for nonlinear imaging in biological tissues. While the optimization of nonlinear signals might suffer from low signal to noise conditions and from possible artifacts at large penetration depths, it has nevertheless been largely used in the multiple scattering regime since it provides a guide star mechanism as well as an intrinsic compensation for spatiotemporal distortions. Here, we demonstrate the benefit of Transmission Matrix (TM) based approaches under broadband illumination conditions, to perform nonlinear imaging. Using ultrashort pulse illumination with spectral bandwidth comparable but still lower than the spectral width of the scattering medium, we show strong nonlinear enhancements of several orders of magnitude, through thicknesses of a few transport mean free paths, which corresponds to millimeters in biological tissues. Linear TM refocusing ...
Energy Technology Data Exchange (ETDEWEB)
Sun, Xiaohua, E-mail: mksxh@163.com; Zhou, Xin; Xu, Yalong; Sun, Panpan; Huang, Niu; Sun, Yihua
2015-05-15
Graphical abstract: - Highlights: • Mixed P25 nanoparticles and large rutile particles were employed to form a top scattering layer. • The top scattering layer exhibits superior light scattering effect. • The bottom nanocrystalline TiO{sub 2} layer can make good use of the back-scattered light. • Bilayer TiO{sub 2} photoanode shows faster interfacial electron transfer and slower charge recombination process. • Bilayer photoanode enhances the DSSC efficiency by a factor of 25%. - Abstract: Herein, we report a bilayer TiO{sub 2} photoanode composed of nanocrystalline TiO{sub 2} (NCT) bottom layer and mixed P25 nanoparticles and large rutile particles (PR) top scattering layer. The present structure performs well in solar light harvesting which is mainly attributed to the fact that the top scattering layer exhibits superior light scattering effect and meanwhile the NCT bottom layer with large dye-loading capacity can make better use of the back-scattered light. Moreover, electrochemical impedance spectroscopy and open circuit voltage decay measurements demonstrate that DSSC based on bilayer photoanode shows faster interfacial electron transfer and slower charge recombination process than that based on NCT monolayer photoanode. These advantages render the DSSCs based on NCT-PR bilayer photoanode exhibiting superior performance under AM1.5G simulated solar irradiation. As an example, by tuning mass ratio between P25 nanoparticles and large rutile particles in the top scattering layer, the DSSC based on NCT-PR bilayer photoanode exhibits an optimum solar energy conversion efficiency of 9.0%, which is about 1.25 times higher than that of monolayer NCT device (7.2%) with the same film thickness.
Eisenhart, Thomas T; Howland, William C; Dempsey, Jillian L
2016-08-18
The proton-coupled electron transfer (PCET) oxidation of p-aminophenol in acetonitrile was initiated via stopped-flow rapid-mixing and spectroscopically monitored. For oxidation by ferrocenium in the presence of 7-(dimethylamino)quinoline proton acceptors, both the electron transfer and proton transfer components could be optically monitored in the visible region; the decay of the ferrocenium absorbance is readily monitored (λmax = 620 nm), and the absorbance of the 2,4-substituted 7-(dimethylamino)quinoline derivatives (λmax = 370-392 nm) red-shifts substantially (ca. 70 nm) upon protonation. Spectral analysis revealed the reaction proceeds via a stepwise electron transfer-proton transfer process, and modeling of the kinetics traces monitoring the ferrocenium and quinolinium signals provided rate constants for elementary proton and electron transfer steps. As the pKa values of the conjugate acids of the 2,4-R-7-(dimethylamino)quinoline derivatives employed were readily tuned by varying the substituents at the 2- and 4-positions of the quinoline backbone, the driving force for proton transfer was systematically varied. Proton transfer rate constants (kPT,2 = (1.5-7.5) × 10(8) M(-1) s(-1), kPT,4 = (0.55-3.0) × 10(7) M(-1) s(-1)) were found to correlate with the pKa of the conjugate acid of the proton acceptor, in agreement with anticipated free energy relationships for proton transfer processes in PCET reactions. PMID:27500804
Optimization of heat transfer utilizing graph based evolutionary algorithms
International Nuclear Information System (INIS)
This paper examines the use of graph based evolutionary algorithms (GBEAs) for optimization of heat transfer in a complex system. The specific case examined in this paper is the optimization of heat transfer in a biomass cookstove utilizing three-dimensional computational fluid dynamics to generate the fitness function. In this stove hot combustion gases are used to heat a cooking surface. The goal is to provide an even spatial temperature distribution on the cooking surface by redirecting the flow of combustion gases with baffles. The variables in the optimization are the position and size of the baffles, which are described by integer values. GBEAs are a novel type of EA in which a topology or geography is imposed on an evolving population of solutions. The choice of graph controls the rate at which solutions can spread within the population, impacting the diversity of solutions and convergence rate of the EAs. In this study, the choice of graph in the GBEAs changes the number of mating events required for convergence by a factor of approximately 2.25 and the diversity of the population by a factor of 2. These results confirm that by tuning the graph and parameters in GBEAs, computational time can be significantly reduced
Charge Transfer Based Colorimetric Detection of Silver Ion
International Nuclear Information System (INIS)
We have demonstrated the colorimetric chemosensor for detection of Ag+ via formation of nanoparticles which is based on the intramolecular CT interaction between the electron-rich (2,6-dialkoxynaphthalene; Np) moiety and the electron-deficient (methyl viologen; MV2+) moiety of a single sensor molecule. Under irradiation of light, Ag+ was reduced to very small silver nanoparticle by CT interaction in the presence of OEGs as flexible recognition moiety of Ag+ and stabilizer for Ag nanoparticles, thus Ag nanoparticles resulted to reddish brown in the color change of sensor solution, gradually. Therefore, the charge-transfer interaction between an electron-deficient and an electron-rich units existing at a sensor molecule can be regarded as a new and efficient method to construct various colorimetric chemosensors. Donor.acceptor interactions or charge transfer (CT) interactions are an important class of non-covalent interactions and have been widely exploited in self-assembling systems. Beyond molecular chemistry, supramolecular chemistry aims at constituting highly complex, functional chemical systems from components held together by intermolecular forces. Chemosensors are the molecules of abiotic origin that bind selectively and reversibly with the analyte with concomitant change in one or more properties of the system. The recognition and signaling of ionic and neutral species of varying complexity is one of the most intensively studied areas of contemporary supramolecular chemistry
International Nuclear Information System (INIS)
Proton-antiproton elastic scattering was measured at a centre of mass energy √s = 540 GeV. In the four-momentum transfer range 0.21 2 the t-distribution of about 7000 events is well represented by the exponential shape exp (bt) with slope parameter b = 13.7 +- 0.3 GeV-2. A new measurement of the slope for - t 2 confirms our earlier result, giving evidence for a change of slope of about 4 GeV-2 around - t approx.= 0.15 GeV2. (orig.)
Agueny, Hicham
2015-07-01
We present results for single and double electron captures in intermediate energies H+ and 2H+ projectiles colliding with a helium target. The processes under investigations are treated using a nonperturbative semiclassical approach in combination with Eikonal approximation to calculate the scattering differential cross sections. The latter reveals pronounced minima and maxima in the scattering angles, in excellent agreement with the recent experimental data. It turns out that the present structure depends strongly on the projectile energy and shows only slight variations with different capture channels. The observed structure demonstrates the analogy of atomic de Broglie's matter-wave scattering with λd B=1.3 -3.2 ×10-3 a.u. and Fraunhofer-type diffraction of light waves.
Absorption, refraction and scattering in analyzer-based imaging: comparison of different algorithms.
Diemoz, P. C.; Coan, P.; Glaser, C; Bravin, A.
2010-01-01
Many mathematical methods have been so far proposed in order to separate absorption, refraction and ultra-small angle scattering information in phase-contrast analyzer-based images. These algorithms all combine a given number of images acquired at different positions of the crystal analyzer along its rocking curve. In this paper a comprehensive quantitative comparison between five of the most widely used phase extraction algorithms based on the geometrical optics approximation is presented: t...
Kerr, Christopher J
2015-01-01
The results of processing the data in the dataset "Raw data for neutron scattering experiments described in PhD thesis "NMR and neutron total scattering studies of silicon-based anode materials for lithium-ion batteries""
Sensitivity Analysis of the Scattering-Based SARBM3D Despeckling Algorithm.
Di Simone, Alessio
2016-01-01
Synthetic Aperture Radar (SAR) imagery greatly suffers from multiplicative speckle noise, typical of coherent image acquisition sensors, such as SAR systems. Therefore, a proper and accurate despeckling preprocessing step is almost mandatory to aid the interpretation and processing of SAR data by human users and computer algorithms, respectively. Very recently, a scattering-oriented version of the popular SAR Block-Matching 3D (SARBM3D) despeckling filter, named Scattering-Based (SB)-SARBM3D, was proposed. The new filter is based on the a priori knowledge of the local topography of the scene. In this paper, an experimental sensitivity analysis of the above-mentioned despeckling algorithm is carried out, and the main results are shown and discussed. In particular, the role of both electromagnetic and geometrical parameters of the surface and the impact of its scattering behavior are investigated. Furthermore, a comprehensive sensitivity analysis of the SB-SARBM3D filter against the Digital Elevation Model (DEM) resolution and the SAR image-DEM coregistration step is also provided. The sensitivity analysis shows a significant robustness of the algorithm against most of the surface parameters, while the DEM resolution plays a key role in the despeckling process. Furthermore, the SB-SARBM3D algorithm outperforms the original SARBM3D in the presence of the most realistic scattering behaviors of the surface. An actual scenario is also presented to assess the DEM role in real-life conditions. PMID:27347971
Membrane-based gas transfer: an environmental engineering laboratory.
Kilduff, J; Liu, J X; Komisar, S J
2004-01-01
We propose an educational experience in which students design a membrane gas transfer reactor, construct a bench-scale version in the laboratory, and employ the reactor to measure mass transfer coefficients. The membrane reactor is useful for teaching mass transfer principles because the mass transfer interface is well defined and easily observed. The system can be modeled successfully using straightforward mathematics. The reactor can be designed and constructed by students, using the mathematical model as a basis, providing insight into the physical meaning of model parameters. The proposed membrane system can be readily operated to obtain data that can be employed to develop or modify existing mass transfer correlations. This can provide students with significant insight into the development of mass transfer correlations and how the constants in such correlations are typically determined. These features help promote a deeper understanding of mass transfer principles. PMID:15193094
Energy Technology Data Exchange (ETDEWEB)
Candy, J V; Chambers, D H; Breitfeller, E F; Guidry, B L; Verbeke, J M; Axelrod, M A; Sale, K E; Meyer, A M
2010-03-02
The detection of radioactive contraband is a critical problem is maintaining national security for any country. Photon emissions from threat materials challenge both detection and measurement technologies especially when concealed by various types of shielding complicating the transport physics significantly. This problem becomes especially important when ships are intercepted by U.S. Coast Guard harbor patrols searching for contraband. The development of a sequential model-based processor that captures both the underlying transport physics of gamma-ray emissions including Compton scattering and the measurement of photon energies offers a physics-based approach to attack this challenging problem. The inclusion of a basic radionuclide representation of absorbed/scattered photons at a given energy along with interarrival times is used to extract the physics information available from the noisy measurements portable radiation detection systems used to interdict contraband. It is shown that this physics representation can incorporated scattering physics leading to an 'extended' model-based structure that can be used to develop an effective sequential detection technique. The resulting model-based processor is shown to perform quite well based on data obtained from a controlled experiment.
International Nuclear Information System (INIS)
The uniform method of numerical investigation of bound states and scattering processes 2→ 2 (including resonance states) in the Coulomb three-body (CTB) systems is developed. It is based on the adiabatic hyperspherical approach (AHSA) and includes the numerical realization and applications to the three-body mesic atomic systems. The results of calculations of bound states of these systems (including the local characteristics of the wave functions) and the scattering processes 2→ 2 (including the characteristics of the resonance states) are presented
International Nuclear Information System (INIS)
At the Darmstadt Linear Accelerator cross sections for the elastic electron scattering on 3He and 4He were measured at energies between 30 and 60 MeV and at scattering angles between 450 and 1290. It deals with relative measurements to the protons respectively with measurements of cross section ratios of 3He to 4He. The main demand of the studies is the acquisition of systematic uncertainties at gas targets. With this the error bounds in the ratios could remarkably be reduced as against earlier electron scattering measurements. At small momentum transfer the rms radius respectively the radius difference is obtained nearly model independently. The uncertainty due to application of a special charge distribution in the evaluation is small as against to the indicated errors. The result are with Rsub(3,4)=2sub(3,4)>1/2 and deltaR = R4 - R3: R4 = (1.696+-0.014) fm and deltaR = -(0.271 +- 0.015) fm. (orig.)
Controlling Kondo-like Scattering at the SrTiO3-based Interfaces
Han, K.; Palina, N.; Zeng, S. W.; Huang, Z.; Li, C. J.; Zhou, W. X.; Wan, D.-Y.; Zhang, L. C.; Chi, X.; Guo, R.; Chen, J. S.; Venkatesan, T.; Rusydi, A.; Ariando
2016-05-01
The observation of magnetic interaction at the interface between nonmagnetic oxides has attracted much attention in recent years. In this report, we show that the Kondo-like scattering at the SrTiO3-based conducting interface is enhanced by increasing the lattice mismatch and growth oxygen pressure PO2. For the 26-unit-cell LaAlO3/SrTiO3 (LAO/STO) interface with lattice mismatch being 3.0%, the Kondo-like scattering is observed when PO2 is beyond 1 mTorr. By contrast, when the lattice mismatch is reduced to 1.0% at the (La0.3Sr0.7)(Al0.65Ta0.35)O3/SrTiO3 (LSAT/STO) interface, the metallic state is always preserved up to PO2 of 100 mTorr. The data from Hall measurement and X-ray absorption near edge structure (XANES) spectroscopy reveal that the larger amount of localized Ti3+ ions are formed at the LAO/STO interface compared to LSAT/STO. Those localized Ti3+ ions with unpaired electrons can be spin-polarized to scatter mobile electrons, responsible for the Kondo-like scattering observed at the LAO/STO interface.
Monte Carlo simulation of novel breast imaging modalities based on coherent x-ray scattering
International Nuclear Information System (INIS)
We present upgraded versions of MC-GPU and penEasyImaging, two open-source Monte Carlo codes for the simulation of radiographic projections and CT, that have been extended and validated to account for the effect of molecular interference in the coherent x-ray scatter. The codes were first validation by comparison between simulated and measured energy dispersive x-ray diffraction (EDXRD) spectra. A second validation was by evaluation of the rejection factor of a focused anti-scatter grid. To exemplify the capabilities of the new codes, the modified MC-GPU code was used to examine the possibility of characterizing breast tissue composition and microcalcifications in a volume of interest inside a whole breast phantom using EDXRD and to simulate a coherent scatter computed tomography (CSCT) system based on first generation CT acquisition geometry. It was confirmed that EDXRD and CSCT have the potential to characterize tissue composition inside a whole breast. The GPU-accelerated code was able to simulate, in just a few hours, a complete CSCT acquisition composed of 9758 independent pencil-beam projections. In summary, it has been shown that the presented software can be used for fast and accurate simulation of novel breast imaging modalities relying on scattering measurements and therefore can assist in the characterization and optimization of promising modalities currently under development. (paper)
Back, Seon-Woo; Lee, Yong-Geon; Lee, Sang-Shin; Son, Geun-Sik
2016-08-22
A moisture-insensitive optical fingerprint scanner (FPS) that is based on polarization resolved in-finger light is proposed and realized. Incident visible light, which is selectively fed to a fingerprint sample via a polarization beam splitter (PBS), is deemed to be partially scattered backward by tissues associated with the skin of the finger. The backscattered light is mostly index-guided in the ridge comprising the fingerprint, which has a higher refractive index, and is drastically dispersed in the valley, which is typically filled with water or air and so has a lower index. However, when light reflects directly off the surface of the finger skin, it fundamentally prevents the scanned image from being determined. The proposed FPS produces bright and dark intensity patterns that are alternately created on the surface of the PBS and correspond to the ridges and valleys, respectively. Thus, this method can especially distinguish between a fake synthetic fingerprint and a genuine fingerprint due to its use of in-finger scattered light. The scanner has been rigorously designed by carrying out ray-optic simulations depending on the wavelength, with tissue-induced scattering taken into account. The device was constructed by incorporating a wire-grid type PBS in conjunction with visible LED sources, including blue, green and red. The scanner adopting a blue LED, which exhibits the strongest light scattering, resulted in the best fingerprint image, enabling enhanced fidelity under the wet and dry situations. Finally, a fake synthetic fingerprint could be successfully discriminated. PMID:27557199
DEFF Research Database (Denmark)
de Nijs, Robin; Lagerburg, Vera; Klausen, Thomas L;
2014-01-01
PURPOSE: Patient-specific dosimetry of lutetium-177 ((177)Lu)-DOTATATE treatment in neuroendocrine tumours is important, because uptake differs across patients. Single photon emission computer tomography (SPECT)-based dosimetry requires a conversion factor between the obtained counts and the...... activity, which depends on the collimator type, the utilized energy windows and the applied scatter correction techniques. In this study, energy window subtraction-based scatter correction methods are compared experimentally and quantitatively. MATERIALS AND METHODS: (177)Lu SPECT images of a phantom with...... technique, the measured ratio was close to the real ratio, and the differences between spheres were small. CONCLUSION: For quantitative (177)Lu imaging MEGP collimators are advised. Both energy peaks can be utilized when the ESSE correction technique is applied. The difference between the calculated and the...
Shi, X.; Lu, L.; Yang, S.; Huang, G.; Zhao, Z.
2015-06-01
For wide application of change detection with SAR imagery, current processing technologies and methods are mostly based on pixels. It is difficult for pixel-based technologies to utilize spatial characteristics of images and topological relations of objects. Object-oriented technology takes objects as processing unit, which takes advantage of the shape and texture information of image. It can greatly improve the efficiency and reliability of change detection. Recently, with the development of polarimetric synthetic aperture radar (PolSAR), more backscattering features on different polarization state can be available for usage of object-oriented change detection study. In this paper, the object-oriented strategy will be employed. Considering the fact that the different target or target's state behaves different backscattering characteristics dependent on polarization state, an object-oriented change detection method that based on weighted polarimetric scattering difference of PolSAR images is proposed. The method operates on the objects generated by generalized statistical region merging (GSRM) segmentation processing. The merit of GSRM method is that image segmentation is executed on polarimetric coherence matrix, which takes full advantages of polarimetric backscattering features. And then, the measurement of polarimetric scattering difference is constructed by combining the correlation of covariance matrix and the difference of scattering power. Through analysing the effects of the covariance matrix correlation and the scattering echo power difference on the polarimetric scattering difference, the weighted method is used to balance the influences caused by the two parts, so that more reasonable weights can be chosen to decrease the false alarm rate. The effectiveness of the algorithm that proposed in this letter is tested by detection of the growth of crops with two different temporal radarsat-2 fully PolSAR data. First, objects are produced by GSRM algorithm
Xiao, Yongchuan; Guo, Jing; Wu, Kui; Qu, Pengfei; Qi, Huajuan; Liu, Caixia; Ruan, Shengping; Chen, Weiyou; Dong, Wei
2013-02-11
A single passband microwave photonic filter with ultrawide tunable range based on stimulated Brillouin scattering is theoretically analyzed. Combining the gain and loss spectrums, tuning range with 44GHz is obtained without crosstalk by introducing two pumps. Adding more pumps, Tuning range multiplying with the multiplication factor equaling to the total quantity of pump can be achieved, which has potential application in microwave and millimeter wave wireless communication systems. PMID:23481728
Chen, Nan-Wei; Lu, Mingyu; Capolino, Filippo; Shanker, Balasubramaniam; Michielssen, Eric
2005-08-01
A Floquet wave-based algorithm for solving an electric field time domain integral equation pertinent to the analysis of transient plane wave scattering from doubly periodic, discretely planar, perfect electrically conducting structures is presented. The proposed scheme accelerates the evaluation of fields generated by periodic constellations of band-limited transient currents via their expansion in time domain Floquet waves and use of blocked fast Fourier transforms. The validity and effectiveness of the resulting algorithm are demonstrated through a number of examples.
MST data exchange through the NCAR incoherent-scatter radar data base
Richmond, A. D.
1986-01-01
One means of making MST (mesosphere stratosphere troposphere) radar data more easily accessible for scientific research by the general scientific community is through a centralized data base. Such a data base can be designed to readily provide information on data availability and quality, and to provide copies of data from any radar in a common format to the user. The ionospheric incoherent scatter community has established a centralized data base at NCAR that may serve not only as a model for a possible MST data base, but also as a catalyst for getting an MST data base started. (Some key elements of the NCAR data base are given.) The NCAR data base can include MST data in the same framework with relatively little extra effort. They are willing to handle MST data on a limited basis in order to permit assessment of community interest and in order to provide some experience with a centralized data base for MST data.
Şenyiğit, M.
2016-09-01
The half-space albedo problem has been solved for a combination of Rayleigh and isotropic scattering using HN method which is developed for the neutron transport studies. The numerical results are compared with exact values obtained using variational method and Chandrasekhar's equation for the {H}-matrix. The analytical solutions of HN method are easy to handle in comparison with the other methods. The numerical results are in good agreement with previous works in literature.
Energy Technology Data Exchange (ETDEWEB)
Lipinski, W.; Z' Graggen, A.; Steinfeld, A. [ETH, Swiss Federal Institute of Technology, Zurich (Switzerland)
2005-05-01
A nonisothermal, nongray, absorbing, emitting, and anisotropically scattering suspension of reacting particles exposed to concentrated thermal radiation is considered. The steam gasification of coal is selected as the model thermochemical reaction. The unsteady energy equation that couples the radiative heat flux with the chemical kinetics is solved by means of a numerical model that incorporates Monte Carlo ray tracing, the finite-volume method, and an explicit Euler time integration scheme. Two modeling approaches are applied: (1) a quasi-continuous model that assumes a homogeneous medium and utilizes its macroscopic radiative properties (absorption and scattering efficiencies and scattering phase function), and (2) a particle-discrete model that assumes an ensemble of randomly positioned particles and traces the interaction of radiation with each particle by geometric optics. Temperature profiles and reaction extent are computed using both approaches. The quasi-continuous approach is superior in accuracy at the expense of lower spatial resolution, while the particle-discrete approach gives detailed information for every single particle in the suspension at the expense of larger stochastic errors.
A radiosity-based model to compute the radiation transfer of soil surface
Zhao, Feng; Li, Yuguang
2011-11-01
A good understanding of interactions of electromagnetic radiation with soil surface is important for a further improvement of remote sensing methods. In this paper, a radiosity-based analytical model for soil Directional Reflectance Factor's (DRF) distributions was developed and evaluated. The model was specifically dedicated to the study of radiation transfer for the soil surface under tillage practices. The soil was abstracted as two dimensional U-shaped or V-shaped geometric structures with periodic macroscopic variations. The roughness of the simulated surfaces was expressed as a ratio of the height to the width for the U and V-shaped structures. The assumption was made that the shadowing of soil surface, simulated by U or V-shaped grooves, has a greater influence on the soil reflectance distribution than the scattering properties of basic soil particles of silt and clay. Another assumption was that the soil is a perfectly diffuse reflector at a microscopic level, which is a prerequisite for the application of the radiosity method. This radiosity-based analytical model was evaluated by a forward Monte Carlo ray-tracing model under the same structural scenes and identical spectral parameters. The statistics of these two models' BRF fitting results for several soil structures under the same conditions showed the good agreements. By using the model, the physical mechanism of the soil bidirectional reflectance pattern was revealed.
Li, Xuesong; Northrop, William F.
2016-04-01
This paper describes a quantitative approach to approximate multiple scattering through an isotropic turbid slab based on Markov Chain theorem. There is an increasing need to utilize multiple scattering for optical diagnostic purposes; however, existing methods are either inaccurate or computationally expensive. Here, we develop a novel Markov Chain approximation approach to solve multiple scattering angular distribution (AD) that can accurately calculate AD while significantly reducing computational cost compared to Monte Carlo simulation. We expect this work to stimulate ongoing multiple scattering research and deterministic reconstruction algorithm development with AD measurements.
School-Based Management: The Advantages of Lump-Sum Transfers.
Neal, Richard G.
1994-01-01
Indicates the advantages under school-based management of transferring funds to the individual schools in a lump sum with minimal encumbrances, along with the freedom to transfer funds within the school budget. Transferring money to the schools, along with corresponding decision-making powers, enhances responsibility and accountability. (MLF)
A theoretical approach to room acoustic simulations based on a radiative transfer model
DEFF Research Database (Denmark)
Ruiz-Navarro, Juan-Miguel; Jacobsen, Finn; Escolano, José;
2010-01-01
A theoretical approach to room acoustic simulations based on a radiative transfer model is developed by adapting the classical radiative transfer theory from optics to acoustics. The proposed acoustic radiative transfer model expands classical geometrical room acoustic modeling algorithms by inco...
Calculation of Single Scattering Parameters in Vector Radiative Transfer Equation%辐射传输方程中的单次散射参数计算
Institute of Scientific and Technical Information of China (English)
王海华; 孙贤明; 刘万强; 申晋; 刘伟
2011-01-01
Based on Mie theory, the single scattering characteristics of a cluster of polydisperse spherical aerosols are calculated. The size distribution of particles is Gamma distribution and effective radii are 5.56, 7, 11 μm,respectively. The average extinction coefficients, average scattering coefficients, single scattering albedos,asymmetry parameters and elements of single scattering phase matrix in the spectral range of 0.4 ～ 100 μm are analyzed. The numerical results show that the single scattering properties of aerosols are seldom affected by particle effective radius in visual light waveband, but greater at higher waveband. The single scattering albedo approximately equals 1 at visual light waveband and the characteristics of single scattering albedo are opposite to the imagery part of refraction index. The polarization ratios of single scattering phase matrix are more sensitive to particle size than phase functions.%根据米氏(Mie)理论,计算了多分散球形气溶胶粒子的单次散射特性.粒子的尺寸分布为伽马分布,有效半径分别为5.56.7和11 μm,分析了0.4-100 μm光谱范围内气溶胶粒子的平均消光系数、平均散射系数、单次散射反照率、不对称因子以及相矩阵与粒子的尺寸参数以及折射率的关系.结果表明,在可见光波段,粒子的有效半径对粒子的散射特性影响较小,在更长的波段上其影响较大;单次散射反照率在可见光范围内近似为1,随波长的变化和水滴折射率虚部随波长的变化曲线正好相反,这说明影响其大小的主要因素为粒子的折射率,即虚部越大则反照率越小;且极化率对粒子的尺寸比相函数更敏感.
Energy Technology Data Exchange (ETDEWEB)
Meziane, M; Brash, E J; Jones, M K; Luo, W; Pentchev, L; Perdrisat, C F; Puckett, A J.R.; Punjabi, V; Wesselmann, F R; Ahmidouch, A; Albayrak, I; Aniol, K A; Arrington, J; Asaturyan, A; Ates, O; Baghdasaryan, H; Benmokhtar, F; Bertozzi, W; Bimbot, L; Bosted, P; Boeglin, W; Butuceanu, C; Carter, P; Chernenko, S; Christy, E; Commisso, M; Cornejo, J C; Covrig, S; Danagoulian, S; Daniel, A; Davidenko, A; Day, D; Dhamija, S; Dutta, D; Ent, R; Frullani, S; Fenker, H; Frlez, E; Garibaldi, F; Gaskell, D; Gilad, S; Goncharenko, Y; Hafidi, K; Hamilton, D; Higinbothan, D W; Hinton, W; Horn, T; Hu, B; Huang, J; Huber, G M; Jensen, E; Kang, H; Keppel, C; Khandaker, M; King, P; Kirillov, D; Kohl, M; Kravtsov, V; Kumbartzki, G; Li, Y; Mamyan, V; Margaziotis, D J; Markowitz, P; Marsh, A; Matulenko, Y; Maxwell, J; Mbianda, G; Meekins, D; Melnick, Y; Miller, J; Mkrtchyan, A; Mkrtchyan, H; Moffit, B; Moreno, O; Mulholland, J; Narayan, A; Nuruzzaman,; Nedev, S; Piasetzky, E; Pierce, W; Piskunov, N M; Prok, Y; Ransome, R D; Razin, D S; Reimer, P E; Reinhold, J; Rondon, O; Shabestari, M; Shahinyan, A; Shestermanov, K; Sirca, S; Sitnik, I; Smykov, L; Smith, G; Solovyev, L; Solvignon, P; Subedi, R; Suleiman, R; Tomasi-Gustafsson, E; Vasiliev, A; Vanderhaeghen, M; Veilleux, M; Wojtsekhowski, B B; Wood, S; Ye, Z; Zanevsky, Y; Zhang, X; Zhang, Y; Zheng, X; Zhu, L
2011-04-01
Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton electric to magnetic form factor ratio, $G_{E}/G_{M}$, obtained separately from cross section and polarization transfer measurements. One possible explanation for this difference is a two-photon-exchange (TPEX) contribution. In an effort to search for effects beyond the one-photon-exchange or Born approximation, we report measurements of polarization transfer observables in the elastic $H(\\vec{e},e'\\vec{p})$ reaction for three different beam energies at a fixed squared momentum transfer $Q^2 = 2.5$ GeV$^2$, spanning a wide range of the virtual photon polarization parameter, $\\epsilon$. From these measured polarization observables, we have obtained separately the ratio $R$, which equals $\\mu_p G_{E}/G_{M}$ in the Born approximation, and the longitudinal polarization transfer component $P_\\ell$, with statistical and systematic uncertainties of $\\Delta R \\approx \\pm 0.01 \\mbox{(stat)} \\pm 0.013 \\mbox{(syst)}$ and $\\Delta P_\\ell/P^{Born}_{\\ell} \\approx \\pm 0.006 \\mbox{(stat)}\\pm 0.01 \\mbox{(syst)}$. The ratio $R$ is found to be independent of $\\epsilon$ at the 1.5% level, while the $\\epsilon$ dependence of $P_\\ell$ shows an enhancement of $(2.3 \\pm 0.6) %$ relative to the Born approximation at large $\\epsilon$.
Yang, C. H.; Soergel, U.
2015-08-01
Persistent Scatterer Interferometry (PSI) is a technique to extract subtle surface deformation from sets of scatterers identified in time-series of SAR images which feature temporally stable and strong radar signal (i.e., Persistent Scatterers, PS). Because of the preferred rectangular and regular structure of man-made objects, PSI works particularly well for monitoring of settlements. Usually, in PSI it is assumed that except for surface motion the scene is steady. In case this is not given, corresponding PS candidates are discarded during PSI processing. On the other hand, pixel-based change detection relying on local comparison of multi-temporal images typically highlights scene modifications of larger size rather than detail level. In this paper, we propose a method to combine these two types of change detection approaches. First, we introduce a local change-index based on PSI, which basically looks for PS candidates that remain stable over a certain period of time, but then break down suddenly. In addition, for the remaining PS candidates we apply common PSI processing which yields attributes like velocity in line-of-sight. In order to consider context, we apply now spatial filtering according to the derived attributes and morphology to exclude outliers and extract connect components of similar regions at the same time. We demonstrate our approach for test site Berlin, Germany, where, firstly, deformation-velocities on man-made structures are estimated and, secondly, some construction-sites are correctly recognized.
14 CFR 91.863 - Transfers of Stage 2 airplanes with base level.
2010-01-01
... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Transfers of Stage 2 airplanes with base... Noise Limits § 91.863 Transfers of Stage 2 airplanes with base level. (a) Stage 2 airplanes may be... the corresponding number of Stage 2 airplanes. (b) No portion of a U.S. operator's base...
Directory of Open Access Journals (Sweden)
Tuija Kangasmaa
2012-01-01
Full Text Available Simultaneous Tl-201/Tc-99m dual isotope myocardial perfusion SPECT is seriously hampered by down-scatter from Tc-99m into the Tl-201 energy window. This paper presents and optimises the ordered-subsets-expectation-maximisation-(OS-EM- based reconstruction algorithm, which corrects the down-scatter using an efficient Monte Carlo (MC simulator. The algorithm starts by first reconstructing the Tc-99m image with attenuation, collimator response, and MC-based scatter correction. The reconstructed Tc-99m image is then used as an input for an efficient MC-based down-scatter simulation of Tc-99m photons into the Tl-201 window. This down-scatter estimate is finally used in the Tl-201 reconstruction to correct the crosstalk between the two isotopes. The mathematical 4D NCAT phantom and physical cardiac phantoms were used to optimise the number of OS-EM iterations where the scatter estimate is updated and the number of MC simulated photons. The results showed that two scatter update iterations and 105 simulated photons are enough for the Tc-99m and Tl-201 reconstructions, whereas 106 simulated photons are needed to generate good quality down-scatter estimates. With these parameters, the entire Tl-201/Tc-99m dual isotope reconstruction can be accomplished in less than 3 minutes.
Windows pollution problems of the dust concentration measurement based on scattering method
International Nuclear Information System (INIS)
The windows are separated the measurement system from the dust space in the light Scattering dust concentration measurement system. The windows are polluted unavoidably by the dust and the measurement error is produced. Based on the Mie Scattering theory, the measurement error is researched in this paper. The numerical simulation results show that the measurement error is related to the particles diameter distribution and the refractive index, but is independent of the particles average diameter. A novel photoelectricity sensor is developed in this paper in order to solve the measurement error by the windows pollution. The calculated method is brought out which can amend the measurement errors by the windows pollution and improve the measurement accuracy.
Modular Python-based Code for Thomson Scattering System on NSTX-U
Horowitz, Benjamin; Diallo, Ahmed; Feibush, Eliot; Leblanc, Benoit
2013-10-01
Fast accurate and reliable measurements of electron temperature and density profiles within magnetically confined plasmas are essential for full operation of fusion devices. We detail the design and implementation of a modular Pythonbased code for the Thomson Scattering diagnostic system of NSTX-U which offers improvements in speed by making full use of the Python's architecture, open-source module packages, and ability to be parallelized across many processors. SciPy's weave package allows the implementation of C/C++ code within our program to clear up bottlenecks in data fitting while not loosing the flexibility and clarity of Python, while Numpy and MatplotLib allow calculations and plotting of the processed data. Using the standard MDSplus input, we create a flexible and expandable algorithm structure which can be implemented on any fusion device utilizing polychromator-based Thomson scattering diagnostic system. Supported by DOE SULI Fellowship at Princeton Plasma Physics Lab.
Fast 3D EM scattering and radiation solvers based on MLFMA
Institute of Scientific and Technical Information of China (English)
Hu Jun; Nie Zaiping; Lei Lin; Hu Jie; Gong Xiaodong; Zhao Huapeng
2008-01-01
As the fastest integral equation solver to date, the multilevel fast multipole algorithm (MLFMA)has been applied successfully to solve electromagnetic scattering and radiation from 3D electrically large objects.But for very large-scale problems, the storage and CPU time required in MLFMA are still expensive. Fast 3D electromagnetic scattering and radiation solvers are introduced based on MLFMA. A brief review of MLFMA is first given. Then, four fast methods including higher-order MLFMA (HO-MLFMA), fast far field approximation combined with adaptive ray propagation MLFMA (FAFFA-ARP-MLFMA), local MLFMA and parallel MLFMA are introduced. Some typical numerical results demonstrate the efficiency of these fast methods.
Brightening Gold Nanoparticles: New Sensing Approach Based on Plasmon Resonance Energy Transfer
Lei Shi; Chao Jing; Zhen Gu; Yi-Tao Long
2015-01-01
Scattering recovered plasmonic resonance energy transfer (SR-PRET) was reported by blocking the plasmon resonance energy transfer (PRET) from gold nanoparticle (GNP) to the adsorbed molecules (RdBS). Due to the selective cleavage of the Si-O bond by F− ions, the quenching is switched off causing an increase in the brightness of the GNPs,detected using dark-field microscopy (DFM) were brightened. This method was successfully applied to the determination of fluoride ions in water. The SR-PRET p...
International Nuclear Information System (INIS)
The SPS WA9 experiment is dealing with the ratio rho=ReA/ImA, between the real part and the imaginary part of the hadron elastic amplitude, in view of the possibility to have a relation between the real part of the amplitude and the very high energy cross section, by using both the optical theorem and the dispersion relations (including the contribution of the different Regge Poles). In the SPS WA9 experiment (Clermont-Ferrand, Leningrad, Lyon, Uppsala collaboration), rho is measured in the Coulomb-nuclear interference region for several elastic scattering reactions (pp, πp, Kp) and energies up to 150 GeV
Fast integrator based data acquisition system for the SST-1 Thomson scattering system
International Nuclear Information System (INIS)
An operational transconductance amplifier based fast charge-integrating module (FCIM) is designed and developed for an easy acquisition of fast Thomson scattered and background signal. FCIM based data acquisition technique can be used for the measurement of charge pulses of <20 ns duration. The response of the module is tested using a standard pulsed charge-generating module. The measuring charge range of the module depends on the integrating capacitor. Comparison of the performance of FCIM to commercially available module shows that it has better dynamic range with higher sensitivity and less measurement error. The module is quite cost effective and has many new features.
Radioactive Threat Detection with Scattering Physics: A Model-Based Application
Energy Technology Data Exchange (ETDEWEB)
Candy, J V; Chambers, D H; Breitfeller, E F; Guidry, B L; Verbeke, J M; Axelrod, M A; Sale, K E; Meyer, A M
2010-01-21
The detection of radioactive contraband is a critical problem in maintaining national security for any country. Emissions from threat materials challenge both detection and measurement technologies especially when concealed by various types of shielding complicating the transport physics significantly. The development of a model-based sequential Bayesian processor that captures both the underlying transport physics including scattering offers a physics-based approach to attack this challenging problem. It is shown that this processor can be used to develop an effective detection technique.
Internet-based transfer of cardiac ultrasound images
Firstenberg, M. S.; Greenberg, N. L.; Garcia, M. J.; Morehead, A. J.; Cardon, L. A.; Klein, A. L.; Thomas, J. D.
2000-01-01
A drawback to large-scale multicentre studies is the time required for the centralized evaluation of diagnostic images. We evaluated the feasibility of digital transfer of echocardiographic images to a central laboratory for rapid and accurate interpretation. Ten patients undergoing trans-oesophageal echocardiographic scanning at three sites had representative single images and multiframe loops stored digitally. The images were analysed in the ordinary way. All images were then transferred via the Internet to a central laboratory and reanalysed by a different observer. The file sizes were 1.5-72 MByte and the transfer rates achieved were 0.6-4.8 Mbit/min. Quantitative measurements were similar between most on-site and central laboratory measurements (all P > 0.25), although measurements differed for left atrial width and pulmonary venous systolic velocities (both P < 0.05). Digital transfer of echocardiographic images and data to a central laboratory may be useful for multicentre trials.
The R + D transfer in Spain: diagnostic based 2006 GEM
International Nuclear Information System (INIS)
The main purpose of this research is to analyse in the international context the situation today of the Spanish R and D transference from the scientific field to the firms, using 2006 GEM data as well as complementary data sources. The main findings of the study emphasize a difficult scenario concerning the R and D transference to the Spanish enterprises. Although these negative results, some data suggest a significant improvement in this area in the near future. (Author) 9 refs
Decorde, Nicolas; Sangeetha, Neralagatta M; Viallet, Benoit; Viau, Guillaume; Grisolia, Jérémie; Coati, Alessandro; Vlad, Alina; Garreau, Yves; Ressier, Laurence
2014-12-21
A comprehensive study on the electromechanical behavior of nanoparticle-based resistive strain gauges in action through normal and grazing incidence small angle X-ray scattering (SAXS/GISAXS) investigations is presented. The strain gauges were fabricated from arrays of colloidal gold nanoparticle (NP) wires assembled on flexible polyethylene terephthalate and polyimide substrates by convective self-assembly. Microstructural changes (mean interparticle distance variations) within these NP wires under uniaxial stretching estimated by SAXS/GISAXS are correlated to their macroscopic electrical resistance variations. SAXS measurements suggest a linear longitudinal extension and transversal contraction of the NP wires with applied strain (0 to ∼ 13%). The slope of this longitudinal variation is less than unity, implying a partial strain transfer from the substrate to the NP wires. The simultaneously measured electrical resistance of the strain gauges shows an exponential variation within the elastic domain of the substrate deformation, consistent with electron tunnelling through the interparticle gaps. A slower variation observed within the plastic domain suggests the formation of new electronic conduction pathways. Implications of transversal contraction of the NP wires on the directional sensitivities of strain gauges are evaluated by simulating electronic conduction in models mimicking a realistic NP arrangement. A loss of directionality of the NP-based strain gauges due to transversal current flow within the NP wires is deduced. PMID:25371292
Kato, Hatsuhiro; Kato, Hatsuyoshi
2016-05-01
We proposed a new discretisation scheme for deriving a second-order difference equation from any system being formulated with the weak-form theory framework. The proposed scheme enables us to extend the application range of the recursive transfer method (RTM) and to express perfectly matching conditions for port boundaries in a discrete fashion under the RTM framework. To evaluate the accuracy and demonstrate the validity of the proposed scheme, we discussed the scattering problem governed by the fourth-order differential equation that was hitherto outside the RTM application range. The difference equation can play an important role in maintaining the balance of the bending moment and the shear force at the interface of two segments. Using the new port boundary condition, a quasi-localised wave was extracted and found to be related to the phase shift due to Fano resonance.
Ferreira, Aires; Viana-Gomes, J.; Nilsson, Johan; Mucciolo, Eduardo R.; Peres, Nuno M. R.; Castro Neto, Antonio H.
2011-03-01
We show that a coherent picture for the dc conductivity of monolayer and bilayer graphene emerges from considering that strong short-range potentials are the main source of scattering in these two systems. The origin of the strong short range potentials may lie in adsorbed hydrocarbons at the surface of graphene. The equivalence between results based on the partial wave description of scattering, the Lippmann-Schwinger equation, and the T-matrix approach is established. Scattering due to resonant impurities close to the neutrality point is investigated via a numerical computation of the Kubo formula using a kernel polynomial method. We find that realistic adsorbates originate impurity bands in monolayer and bilayer graphene close to the Dirac point. In the midgap region, a plateau of minimum conductivity of about e2 / h (per layer) is induced by the resonant disorder. In bilayer graphene, a large adsorbate concentration can develop an energy gap between midgap states and high energy states. As a consequence, the conductivity plateau is supressed near the edges and a ``conductivity gap'' takes place.
Full waveform inversion based on scattering angle enrichment with application to real dataset
Wu, Zedong
2015-08-19
Reflected waveform inversion (RWI) provides a method to reduce the nonlinearity of the standard full waveform inversion (FWI). However, the drawback of the existing RWI methods is inability to utilize diving waves and the extra sensitivity to the migrated image. We propose a combined FWI and RWI optimization problem through dividing the velocity into the background and perturbed components. We optimize both the background and perturbed components, as independent parameters. The new objective function is quadratic with respect to the perturbed component, which will reduce the nonlinearity of the optimization problem. Solving this optimization provides a true amplitude image and utilizes the diving waves to update the velocity of the shallow parts. To insure a proper wavenumber continuation, we use an efficient scattering angle filter to direct the inversion at the early stages to direct energy corresponding to large (smooth velocity) scattering angles to the background velocity update and the small (high wavenumber) scattering angles to the perturbed velocity update. This efficient implementation of the filter is fast and requires less memory than the conventional approach based on extended images. Thus, the new FWI procedure updates the background velocity mainly along the wavepath for both diving and reflected waves in the initial stages. At the same time, it updates the perturbation with mainly reflections (filtering out the diving waves). To demonstrate the capability of this method, we apply it to a real 2D marine dataset.
A parallelized Python based Multi-Point Thomson Scattering analysis in NSTX-U
Miller, Jared; Diallo, Ahmed; Leblanc, Benoit
2014-10-01
Multi-Point Thomson Scattering (MPTS) is a reliable and accurate method of finding the temperature, density, and pressure of a magnetically confined plasma. Nd:YAG (1064 nm) lasers are fired into the plasma with a frequency of 60 Hz, and the light is Doppler shifted by Thomson scattering. Polychromators on the midplane of the tokamak pick up the light at various radii/scattering angles, and the avalanche photodiode's voltages are added to an MDSplus tree for later analysis. This project ports and optimizes the prior serial IDL MPTS code into a well-documented Python package that runs in parallel. Since there are 30 polychromators in the current NSTX setup (12 more will be added when NSTX-U is completed), using parallelism offers vast savings in performance. NumPy and SciPy further accelerate numerical calculations and matrix operations, Matplotlib and PyQt make an intuitive GUI with plots of the output, and Multiprocessing parallelizes the computationally intensive calculations. The Python package was designed with portability and flexibility in mind so it can be adapted for use in any polychromator-based MPTS system.
Energy Technology Data Exchange (ETDEWEB)
Kelleher, Aidan [College of William and Mary, Williamsburg, VA (United States)
2010-02-01
Knowledge of the electric and magnetic elastic form factors of the nucleon is essential for an understanding of nucleon structure. Of the form factors, the electric form factor of the neutron has been measured over the smallest range in Q^{2} and with the lowest precision. Jefferson Lab experiment 02-013 used a novel new polarized ^{3} He target to nearly double the range of momentum transfer in which the neutron form factor has been studied and to measure it with much higher precision. Polarized electrons were scattered off this target, and both the scattered electron and neutron were detected. G^{n} _{E} was measured to be 0.0242 ± 0.0020(stat) ± 0.0061(sys) and 0.0247 ± 0.0029(stat) ± 0.0031(sys) at Q^{2} = 1.7 and 2.5 GeV^{2} , respectively.
International Nuclear Information System (INIS)
Three-dimensional dimensionless radiative integral transfer equations (RITEs) for a cubic emitting-absorbing and isotropically scattering homogeneous medium of constant properties bounded by gray walls are solved using the method of “product integration”. The resultant system of linear equations for the incident energy is solved iteratively. Evaluation of the accuracy of the numerical solution is achieved by using the computer codes to make predictions for an idealized enclosure in which the exact analytical solution is possible. Comparison of the analytical and numerical values of medium temperatures and heat fluxes has shown that our method is logically correct and has good accuracy. Four benchmark problems for participating medium subjected to various combinations of internally uniform/non-uniform source terms are solved. To make the benchmark problems more complex and more general, different scattering albedo (ω=0.1, 0.5, 0.9), different wall emissivity (ε=0.1, 0.5, 0.9) and different optical thickness (τ=0.1, 1.0, 5.0) are considered. The solutions for the temperature of the medium and the heat flux components are given in tabular form and they may serve as standard values to assess the accuracy of other methods more conveniently.
Computer-based sensing and visualizing of metal transfer mode in gas metal arc welding
Institute of Scientific and Technical Information of China (English)
Chen Maoai; Wu Chuansong; Lü Yunfei
2008-01-01
Using Xenon lamp lights to overcome the strong interference from the welding arc, a computer-based system is developed to sense and visualize the metal transfer in GMAW. This system combines through-the-arc sensing of the welding current and arc voltage with high speed imaging of the metal transfer. It can simultaneously display the metal transfer processes and waveforms of electrical welding parameters in real-time The metal transfer videos and waveforms of electrical welding parameters can be recorded. Metal transfers under various welding conditions have been investigated with the system developed.
Imaging with Scattered Neutrons
Ballhausen, H; Gähler, R; Trapp, M; Van Overberghe, A
2006-01-01
We describe a novel experimental technique for neutron imaging with scattered neutrons. These scattered neutrons are of interest for condensed matter physics, because they permit to reveal the local distribution of incoherent and coherent scattering within a sample. In contrast to standard attenuation based imaging, scattered neutron imaging distinguishes between the scattering cross section and the total attenuation cross section including absorption. First successful low-noise millimeter-resolution images by scattered neutron radiography and tomography are presented.
Game based learning for 21st century transferable skills: challenges and opportunities
Bellotti, Francesco; Bottino, Rosa Maria; Nadolski, Rob; Fernández Manjón, Baltasar
2012-01-01
Bellotti, F., Bottino, R. M., Nadolski, R. J., & Fernández Manjón, B. (2012, 4-6 July). Game based learning for 21st century transferable skills: challenges and opportunities. Presentation at the Workshop Game based learning for 21st century transferable skills: challenges and opportunities, 12th IE
Symbolic transfer entropy-based premature signal analysis
Wang, Jun; Yu, Zheng-Feng
2012-01-01
In this paper, we use symbolic transfer entropy to study the coupling strength between premature signals. Numerical experiments show that three types of signal couplings are in the same direction. Among them, normal signal coupling is the strongest, followed by that of premature ventricular contractions, and that of atrial premature beats is the weakest. The T test shows that the entropies of the three signals are distinct. Symbolic transfer entropy requires less data, can distinguish the three types of signals and has very good computational efficiency.
Symbolic transfer entropy-based premature signal analysis
International Nuclear Information System (INIS)
In this paper, we use symbolic transfer entropy to study the coupling strength between premature signals. Numerical experiments show that three types of signal couplings are in the same direction. Among them, normal signal coupling is the strongest, followed by that of premature ventricular contractions, and that of atrial premature beats is the weakest. The T test shows that the entropies of the three signals are distinct. Symbolic transfer entropy requires less data, can distinguish the three types of signals and has very good computational efficiency. (interdisciplinary physics and related areas of science and technology)
Broad-band electron spectroscopy a novel concept based on Thomson scattering
Tomassini, P; Giulietti, A; Giulietti, D; Gizzi, L A; Labate, L
2002-01-01
The spectrum of relativistic electron bunches with large energy dispersion is hardly obtainable with conventional magnetic spectrometers. We present a novel spectroscopic concept, based on the analysis of the photons generated by Thomson Scattering of a probe laser pulse inpinging with arbitrary incidence angle onto the electron bunch. The feasibility of a single-pulse spectrometer, using an energy-calibrated CCD device as detector, is investigated. Numerical simulations performed in conditions typical of a real experiment show the effectiveness and accuracy of the new method.
Spectroscopy of laser-plasma accelerated electrons: A novel concept based on Thomson scattering
International Nuclear Information System (INIS)
The spectrum of relativistic electron bunches with large energy dispersion, like the ones usually generated with laser-plasma acceleration processes, is difficult to obtain with conventional methods. A novel spectroscopic concept, based on the analysis of the photons generated by Thomson scattering of a probe laser pulse by the electron bunch, is presented. The feasibility of a single-pulse spectrometer, using an energy-calibrated charge coupled device as detector, is investigated. Numerical simulations performed in conditions typical of a real experiment show the effectiveness and accuracy of the new method
Dual-band bandpass tunable microwave photonic filter based on stimulated Brillouin scattering
Li, Jia-qi; Xiao, Yong-chuan; Dong, Wei; Zhang, Xin-dong
2016-07-01
A dual-band bandpass microwave photonic filter (MPF) based on stimulated Brillouin scattering (SBS) is theoretically analyzed and experimentally demonstrated. Two separated tunable laser sources (TLSs) are employed to generate two passbands by implementing phase modulation to amplitude modulation conversion by using SBS induced sideband amplification. The center frequencies of both passbands can be independently tuned ranging from 1 GHz to 19 GHz. High resolution with 3 dB bandwidth less than 30 MHz and large out-of-band rejection about 40 dB under 25 mW optical pump power are achieved.
A DNA biosensor based on resonance light scattering using unmodified gold bipyramids
International Nuclear Information System (INIS)
We report on a novel biosensor for determining sequence-specific DNA. It is based on resonance light scattering (RLS) caused by the aggregation of gold bipyramids. These display localized surface plasmon resonance and can be used as a bioprobe. The absorption spectra and the transmission electron micrographs provide visual evidence of the aggregation of the gold bipyramids in the presence of DNA. The RLS intensity of the gold bipyramids increases with the concentration of the target DNA. The method was successfully applied to the determination of a 30-mer single-stranded oligonucleotide and works over the 0.1-10 nM concentration range. (author)
Xiaoqiao Deng; Changqing Gu; Bingzheng Xu; Zhuo Li; Xinlei Chen
2013-01-01
The fast dipole method (FDM) is extended to analyze the scattering of dielectric and magnetic materials by solving the volume integral equation (VIE). The FDM is based on the equivalent dipole method (EDM) and can achieve the separation of the field dipole and source dipole, which reduces the complexity of interactions between two far groups (such as group i and group j) from O(NiNj) to O(Ni+Nj), where Ni and Nj are the numbers of dipoles in group i and group j, respectively. Targets includin...
High-energy laser-summator based on Raman scattering principle
Eugeniy Mikhalovich, Zemskov; Zarubin, Peter Vasilievich; Cook, Joung
2013-02-01
This paper is a summary of the history, theory, and development efforts of summator, an all-in-one device that coherently combines multiple high-power laser beams, lowers the beam divergence, and shifts the wavelength based on stimulated Raman scattering principle in USSR from early 1960s to late 1970s. This was a part of the Terra-3 program, which was an umbrella program of highly classified high-energy laser weapons development efforts. Some parts of the Terra-3 program, specifically the terminal missile defense portion, were declassified recently, including the information on summator development efforts.
Institute of Scientific and Technical Information of China (English)
Huang Hao; Pan Minghai; Lu Zhijun
2015-01-01
Hardware-in-the-loop (HWIL) simulation technology can verify and evaluate the radar by simulating the radio frequency environment in an anechoic chamber. The HWIL simulation technology of wide-band radar targets can accurately generate wide-band radar target echo which stands for the radar target scattering characteristics and pulse modulation of radar transmitting sig-nal. This paper analyzes the wide-band radar target scattering properties first. Since the responses of target are composed of many separate scattering centers, the target scattering characteristic is restructured by scattering centers model. Based on the scattering centers model of wide-band radar target, the wide-band radar target echo modeling and the simulation method are discussed. The wide-band radar target echo is reconstructed in real-time by convoluting the transmitting signal to the target scattering parameters. Using the digital radio frequency memory (DRFM) system, the HWIL simulation of wide-band radar target echo with high accuracy can be actualized. A typical wide-band radar target simulation is taken to demonstrate the preferable simulation effect of the reconstruction method of wide-band radar target echo. Finally, the radar target time-domain echo and high-resolution range profile (HRRP) are given. The results show that the HWIL simulation gives a high-resolution range distribution of wide-band radar target scattering centers.
Directory of Open Access Journals (Sweden)
Huang Hao
2015-10-01
Full Text Available Hardware-in-the-loop (HWIL simulation technology can verify and evaluate the radar by simulating the radio frequency environment in an anechoic chamber. The HWIL simulation technology of wide-band radar targets can accurately generate wide-band radar target echo which stands for the radar target scattering characteristics and pulse modulation of radar transmitting signal. This paper analyzes the wide-band radar target scattering properties first. Since the responses of target are composed of many separate scattering centers, the target scattering characteristic is restructured by scattering centers model. Based on the scattering centers model of wide-band radar target, the wide-band radar target echo modeling and the simulation method are discussed. The wide-band radar target echo is reconstructed in real-time by convoluting the transmitting signal to the target scattering parameters. Using the digital radio frequency memory (DRFM system, the HWIL simulation of wide-band radar target echo with high accuracy can be actualized. A typical wide-band radar target simulation is taken to demonstrate the preferable simulation effect of the reconstruction method of wide-band radar target echo. Finally, the radar target time-domain echo and high-resolution range profile (HRRP are given. The results show that the HWIL simulation gives a high-resolution range distribution of wide-band radar target scattering centers.
Ouyang, Wei; Mao, Weijian; Li, Xuelei; Li, Wuqun
2014-08-01
Sound velocity inversion problem based on scattering theory is formulated in terms of a nonlinear integral equation associated with scattered field. Because of its nonlinearity, in practice, linearization algorisms (Born/single scattering approximation) are widely used to obtain an approximate inversion solution. However, the linearized strategy is not congruent with seismic wave propagation mechanics in strong perturbation (heterogeneous) medium. In order to partially dispense with the weak perturbation assumption of the Born approximation, we present a new approach from the following two steps: firstly, to handle the forward scattering by taking into account the second-order Born approximation, which is related to generalized Radon transform (GRT) about quadratic scattering potential; then to derive a nonlinear quadratic inversion formula by resorting to inverse GRT. In our formulation, there is a significant quadratic term regarding scattering potential, and it can provide an amplitude correction for inversion results beyond standard linear inversion. The numerical experiments demonstrate that the linear single scattering inversion is only good in amplitude for relative velocity perturbation () of background media up to 10 %, and its inversion errors are unacceptable for the perturbation beyond 10 %. In contrast, the quadratic inversion can give more accurate amplitude-preserved recovery for the perturbation up to 40 %. Our inversion scheme is able to manage double scattering effects by estimating a transmission factor from an integral over a small area, and therefore, only a small portion of computational time is added to the original linear migration/inversion process.
International Nuclear Information System (INIS)
To provide an ideal solution for a specific problem of gastric cancer detection in which low-scattering regions simultaneously existed with both the non- and high-scattering regions, a novel hybrid radiosity-SP3 equation based reconstruction algorithm for bioluminescence tomography was proposed in this paper. In the algorithm, the third-order simplified spherical harmonics approximation (SP3) was combined with the radiosity equation to describe the bioluminescent light propagation in tissues, which provided acceptable accuracy for the turbid medium with both low- and non-scattering regions. The performance of the algorithm was evaluated with digital mouse based simulations and a gastric cancer-bearing mouse based in situ experiment. Primary results demonstrated the feasibility and superiority of the proposed algorithm for the turbid medium with low- and non-scattering regions
Chen, Xueli; Zhang, Qitan; Yang, Defu; Liang, Jimin
2014-01-01
To provide an ideal solution for a specific problem of gastric cancer detection in which low-scattering regions simultaneously existed with both the non- and high-scattering regions, a novel hybrid radiosity-SP3 equation based reconstruction algorithm for bioluminescence tomography was proposed in this paper. In the algorithm, the third-order simplified spherical harmonics approximation (SP3) was combined with the radiosity equation to describe the bioluminescent light propagation in tissues, which provided acceptable accuracy for the turbid medium with both low- and non-scattering regions. The performance of the algorithm was evaluated with digital mouse based simulations and a gastric cancer-bearing mouse based in situ experiment. Primary results demonstrated the feasibility and superiority of the proposed algorithm for the turbid medium with low- and non-scattering regions.
New trends in nuclear research based on laser Compton scattering γ-ray beams
International Nuclear Information System (INIS)
Laser Compton scattering (LCS) γ-ray has a number of advantages not found in other γ-ray sources, such as quasi-monochrome, variable energy, beam profile, and capability of linear (circular) polarization, and has been used in various fields including nuclear physics research. This paper discusses the development situation of the high-intensity LCS γ-ray source of new generation, as well as the possibility of photonuclear physics. The high-brightness LCS γ-ray source of new generation with the magnitude higher by 4-7 orders than the conventional LCS γ-ray was proposed, and its construction has already been started in Europe. The LCS γ-ray based on energy recovery linac (ERL) was proposed in Japan, too. KEK performed electron acceleration due to compact ERL for demonstrating the principle, and is generating the LCS γ-ray of approximately 7 keV, using a laser stacking cavity built into a compact ERL. As for the studies on photonuclear physics, the following items are reviewed: Studies on nuclear structure based on linearly polarized γ-ray, studies on supernova explosion based on photonuclear reaction, determination of the reaction cross-sectional area of 12C(α,γ)16O in nuclear astrophysics, photonuclear fission, parity non-conservation due to circularly polarized γ-ray, and Delbruck scattering as one of the nonlinear effect of QED. (A.O.)
GPU-based Monte Carlo dust radiative transfer scheme applied to AGN
Heymann, Frank
2012-01-01
A three dimensional parallel Monte Carlo (MC) dust radiative transfer code is presented. To overcome the huge computing time requirements of MC treatments, the computational power of vectorized hardware is used, utilizing either multi-core computer power or graphics processing units. The approach is a self-consistent way to solve the radiative transfer equation in arbitrary dust configurations. The code calculates the equilibrium temperatures of two populations of large grains and stochastic heated polycyclic aromatic hydrocarbons (PAH). Anisotropic scattering is treated applying the Heney-Greenstein phase function. The spectral energy distribution (SED) of the object is derived at low spatial resolution by a photon counting procedure and at high spatial resolution by a vectorized ray-tracer. The latter allows computation of high signal-to-noise images of the objects at any frequencies and arbitrary viewing angles. We test the robustness of our approach against other radiative transfer codes. The SED and dust...
The role of technological transfer in the societies based on knowledge economy
Daniela HÎNCU; FRASINEANU Corina; FRASINEANU Ioan
2009-01-01
The knowledge based economy is an economy based on innovation. Implementing innovation requires acquiring new technology, using the technique of technological transfer. The problems and the timing for implementing an emerging technology are under discussion in this paper.
Electrochemical Sensing Based on Printable Temporary Transfer Tattoos†
Windmiller, Joshua Ray; Bandodkar, Amay Jairaj; Valdés-Ramírez, Gabriela; Parkhomovsky, Serguey; Martinez, Alexandra Gabrielle; Wang, Joseph
2012-01-01
The realization of epidermal chemical sensing requires a fabrication methodology compatible with the non-planarity and irregularities of the human anatomy. This Communication describes the development of printed temporary transfer tattoo (T3) electrochemical sensors for physiological and security monitoring of chemical constituents leading towards the demonstration of ‘electronic skin’.
Energy Technology Data Exchange (ETDEWEB)
Xiangjie, Zhao, E-mail: zxjdouble@163.com, E-mail: zxjdouble@gmail.com; Cangli, Liu; Jiazhu, Duan; Dayong, Zhang; Yongquan, Luo [Institute of Fluid Physics, China Academy of Engineering Physics, 621900 Mianyang (China)
2015-01-07
Optically addressed conventional nematic liquid crystal spatial light modulator has attracted wide research interests. But the slow response speed limited its further application. In this paper, polymer network liquid crystal (PNLC) was proposed to replace the conventional nematic liquid crystal to enhance the response time to the order of submillisecond. The maximum light scattering of the employed PNLC was suppressed to be less than 2% at 1.064 μm by optimizing polymerization conditions and selecting large viscosity liquid crystal as solvent. The occurrence of phase ripple phenomenon due to electron diffusion and drift in photoconductor was found to deteriorate the phase modulation effect of the optical addressed PNLC phase modulator. The wavelength effect and AC voltage frequency effect on the on state dynamic response of phase change was investigated by experimental methods. These effects were interpreted by electron diffusion and drift theory based on the assumption that free electron was inhomogeneously distributed in accordance with the writing beam intensity distribution along the incident direction. The experimental results indicated that the phase ripple could be suppressed by optimizing the wavelength of the writing beam and the driving AC voltage frequency when varying the writing beam intensity to generate phase change in 2π range. The modulation transfer function was also measured.
International Nuclear Information System (INIS)
Optically addressed conventional nematic liquid crystal spatial light modulator has attracted wide research interests. But the slow response speed limited its further application. In this paper, polymer network liquid crystal (PNLC) was proposed to replace the conventional nematic liquid crystal to enhance the response time to the order of submillisecond. The maximum light scattering of the employed PNLC was suppressed to be less than 2% at 1.064 μm by optimizing polymerization conditions and selecting large viscosity liquid crystal as solvent. The occurrence of phase ripple phenomenon due to electron diffusion and drift in photoconductor was found to deteriorate the phase modulation effect of the optical addressed PNLC phase modulator. The wavelength effect and AC voltage frequency effect on the on state dynamic response of phase change was investigated by experimental methods. These effects were interpreted by electron diffusion and drift theory based on the assumption that free electron was inhomogeneously distributed in accordance with the writing beam intensity distribution along the incident direction. The experimental results indicated that the phase ripple could be suppressed by optimizing the wavelength of the writing beam and the driving AC voltage frequency when varying the writing beam intensity to generate phase change in 2π range. The modulation transfer function was also measured
Institute of Scientific and Technical Information of China (English)
DENG Ruru; LIU Qinhuo; KE Ruiping; CHENG Lei; LIU Xiaoping
2004-01-01
It is a valid route for quantitatively remote sensing on water pollution to build a model according to the physical mechanisms of scattering and absorbing of suspended substance, pollutant, and molecules of water. Remote sensing model for water pollution based on single scattering is simple and easy to be used, but the precision is affected by turbidity of water. The characteristics of the energy composition of multiple scattering, are analyzed and it is proposed that, based on the model of single scattering, ifthe flux of the second scattering is considered additionally, the precision of the modelwill be remarkably improved and the calculation is still very simple. The factor of the second scattering is deduced to build a double scattering model, and the practical arithmetic for the calculation of the model is put forward. The result of applying this model in the water area around the Zhujiang(Pearl) River outfall shows that the precision is obviously improved. The result also shows that the seriously polluted water area is distributed in the northeast of Lingding Sea, the Victoria Bay of Hong Kong, and the Shengzhen Bay.
Energy Technology Data Exchange (ETDEWEB)
Warringham, Robbie; McFarlane, Andrew R.; Lennon, David, E-mail: David.Lennon@Glasgow.ac.uk [School of Chemistry, University of Glasgow, Joseph Black Building, Glasgow, Scotland G12 8QQ (United Kingdom); MacLaren, Donald A. [School of Physics and Astronomy, University of Glasgow, The Kelvin Building, Glasgow, Scotland G12 8QQ (United Kingdom); Webb, Paul B.; Tooze, Robert P. [Sasol Technology UK Ltd., Purdie Building, North Haugh, St Andrews, Fife KY16 9ST (United Kingdom); Taylor, Jon; Ewings, Russell A.; Parker, Stewart F. [ISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom)
2015-11-07
An iron based Fischer-Tropsch synthesis catalyst is evaluated using CO hydrogenation at ambient pressure as a test reaction and is characterised by a combination of inelastic neutron scattering (INS), powder X-ray diffraction, temperature-programmed oxidation, Raman scattering, and transmission electron microscopy. The INS spectrum of the as-prepared bulk iron oxide pre-catalyst (hematite, α-Fe{sub 2}O{sub 3}) is distinguished by a relatively intense band at 810 cm{sup −1}, which has previously been tentatively assigned as a magnon (spinon) feature. An analysis of the neutron scattering intensity of this band as a function of momentum transfer unambiguously confirms this assignment. Post-reaction, the spinon feature disappears and the INS spectrum is characterised by the presence of a hydrocarbonaceous overlayer. A role for the application of INS in magnetic characterisation of iron based FTS catalysts is briefly considered.
International Nuclear Information System (INIS)
An iron based Fischer-Tropsch synthesis catalyst is evaluated using CO hydrogenation at ambient pressure as a test reaction and is characterised by a combination of inelastic neutron scattering (INS), powder X-ray diffraction, temperature-programmed oxidation, Raman scattering, and transmission electron microscopy. The INS spectrum of the as-prepared bulk iron oxide pre-catalyst (hematite, α-Fe2O3) is distinguished by a relatively intense band at 810 cm−1, which has previously been tentatively assigned as a magnon (spinon) feature. An analysis of the neutron scattering intensity of this band as a function of momentum transfer unambiguously confirms this assignment. Post-reaction, the spinon feature disappears and the INS spectrum is characterised by the presence of a hydrocarbonaceous overlayer. A role for the application of INS in magnetic characterisation of iron based FTS catalysts is briefly considered
Li, Meng; Jiang, Li-Hui; Xiong, Xing-Long; Ma, Yu-Zhao; Liu, Jie-Sheng
2016-05-01
Layer boundaries detection with LIDAR is of great significance for the meteorological and environmental research. Apart from the background noise, multiple scattering can also seriously affect the detection results in LIDAR signal processing. To alleviate these issues, a novel approach was proposed based upon morphological filtering and multiple scattering correction with multiple iterations, which essentially acts as a weighted algorithm with multiple scattering factors in different filtering scales, and applies integral extinction coefficients as media to perform correction. Simulations on artificial signals and real LIDAR signals support this approach.
Li, Meng; Jiang, Li-Hui; Xiong, Xing-Long; Ma, Yu-Zhao; Liu, Jie-Sheng
2016-08-01
Layer boundaries detection with LIDAR is of great significance for the meteorological and environmental research. Apart from the background noise, multiple scattering can also seriously affect the detection results in LIDAR signal processing. To alleviate these issues, a novel approach was proposed based upon morphological filtering and multiple scattering correction with multiple iterations, which essentially acts as a weighted algorithm with multiple scattering factors in different filtering scales, and applies integral extinction coefficients as media to perform correction. Simulations on artificial signals and real LIDAR signals support this approach.
Gunawan, Aloysius Andhika
Transmission electron microscopy (TEM) relies upon elastic and inelastic scattering signals to perform imaging and analysis of materials. TEM images typically contain contributions from both types of scattering. The ability to separate the contributions from elastic and inelastic processes individually through energy filter or electron energy loss spectroscopy (EELS) allows unique analysis that is otherwise unachievable. Two prominent types of inelastic scattering probed by EELS, namely plasmon and core-loss excitations, are useful for elucidating structural and electronic properties of chalcogenide-based semiconductor nanocrystals. The elastic scattering, however, is still a critical part of the analysis and used in conjunction with the separated inelastic scattering signals. The capability of TEM operated in scanning mode (STEM) to perform localized atomic length scale analysis also permits the understanding of the nanocrystals unattainable by other techniques. Despite the pivotal role of inelastic scatterings, their contributions for STEM imaging, particularly high-angle annular dark field STEM (HAADF-STEM), are not completely understood. This is not surprising since it is currently impossible to experimentally separate the inelastic signals contributing to HAADF-STEM images although images obtained under bright-field TEM mode can be analyzed separately from their scattering contributions using energy-filtering devices. In order to circumvent such problem, analysis based on simulation was done. The existing TEM image simulation algorithm called Multislice method, however, only accounts for elastic scattering. The existing Multislice algorithm was modified to incorporate (bulk or volume) plasmon inelastic scattering. The results were verified based on data from convergent-beam electron diffraction (CBED), electron energy loss spectroscopy (EELS), and HAADF-STEM imaging as well as comparison to experimental data. Dopant atoms are crucial factors which control
Synthetic aperture radar imaging based on attributed scatter model using sparse recovery techniques
Institute of Scientific and Technical Information of China (English)
苏伍各; 王宏强; 阳召成
2014-01-01
The sparse recovery algorithms formulate synthetic aperture radar (SAR) imaging problem in terms of sparse representation (SR) of a small number of strong scatters’ positions among a much large number of potential scatters’ positions, and provide an effective approach to improve the SAR image resolution. Based on the attributed scatter center model, several experiments were performed with different practical considerations to evaluate the performance of five representative SR techniques, namely, sparse Bayesian learning (SBL), fast Bayesian matching pursuit (FBMP), smoothed l0 norm method (SL0), sparse reconstruction by separable approximation (SpaRSA), fast iterative shrinkage-thresholding algorithm (FISTA), and the parameter settings in five SR algorithms were discussed. In different situations, the performances of these algorithms were also discussed. Through the comparison of MSE and failure rate in each algorithm simulation, FBMP and SpaRSA are found suitable for dealing with problems in the SAR imaging based on attributed scattering center model. Although the SBL is time-consuming, it always get better performance when related to failure rate and high SNR.
A systematic approach to robust preconditioning for gradient-based inverse scattering algorithms
International Nuclear Information System (INIS)
This paper presents a systematic approach to robust preconditioning for gradient-based nonlinear inverse scattering algorithms. In particular, one- and two-dimensional inverse problems are considered where the permittivity and conductivity profiles are unknown and the input data consist of the scattered field over a certain bandwidth. A time-domain least-squares formulation is employed and the inversion algorithm is based on a conjugate gradient or quasi-Newton algorithm together with an FDTD-electromagnetic solver. A Fisher information analysis is used to estimate the Hessian of the error functional. A robust preconditioner is then obtained by incorporating a parameter scaling such that the scaled Fisher information has a unit diagonal. By improving the conditioning of the Hessian, the convergence rate of the conjugate gradient or quasi-Newton methods are improved. The preconditioner is robust in the sense that the scaling, i.e. the diagonal Fisher information, is virtually invariant to the numerical resolution and the discretization model that is employed. Numerical examples of image reconstruction are included to illustrate the efficiency of the proposed technique
TH-A-18C-04: Ultrafast Cone-Beam CT Scatter Correction with GPU-Based Monte Carlo Simulation
Energy Technology Data Exchange (ETDEWEB)
Xu, Y [UT Southwestern Medical Center, Dallas, TX (United States); Southern Medical University, Guangzhou (China); Bai, T [UT Southwestern Medical Center, Dallas, TX (United States); Xi' an Jiaotong University, Xi' an (China); Yan, H; Ouyang, L; Wang, J; Pompos, A; Jiang, S; Jia, X [UT Southwestern Medical Center, Dallas, TX (United States); Zhou, L [Southern Medical University, Guangzhou (China)
2014-06-15
Purpose: Scatter artifacts severely degrade image quality of cone-beam CT (CBCT). We present an ultrafast scatter correction framework by using GPU-based Monte Carlo (MC) simulation and prior patient CT image, aiming at automatically finish the whole process including both scatter correction and reconstructions within 30 seconds. Methods: The method consists of six steps: 1) FDK reconstruction using raw projection data; 2) Rigid Registration of planning CT to the FDK results; 3) MC scatter calculation at sparse view angles using the planning CT; 4) Interpolation of the calculated scatter signals to other angles; 5) Removal of scatter from the raw projections; 6) FDK reconstruction using the scatter-corrected projections. In addition to using GPU to accelerate MC photon simulations, we also use a small number of photons and a down-sampled CT image in simulation to further reduce computation time. A novel denoising algorithm is used to eliminate MC scatter noise caused by low photon numbers. The method is validated on head-and-neck cases with simulated and clinical data. Results: We have studied impacts of photo histories, volume down sampling factors on the accuracy of scatter estimation. The Fourier analysis was conducted to show that scatter images calculated at 31 angles are sufficient to restore those at all angles with <0.1% error. For the simulated case with a resolution of 512×512×100, we simulated 10M photons per angle. The total computation time is 23.77 seconds on a Nvidia GTX Titan GPU. The scatter-induced shading/cupping artifacts are substantially reduced, and the average HU error of a region-of-interest is reduced from 75.9 to 19.0 HU. Similar results were found for a real patient case. Conclusion: A practical ultrafast MC-based CBCT scatter correction scheme is developed. The whole process of scatter correction and reconstruction is accomplished within 30 seconds. This study is supported in part by NIH (1R01CA154747-01), The Core Technology Research
Intergenerational knowledge transfer in the academic environment of knowledge-based economy
Viorel Lefter; Constantin Brătianu; Adriana Agapie; Simona Agoston; Ivona Orzea
2011-01-01
In the immediate future, intergenerational knowledge transfer is one of the knowledge-based economy’s main challenges since an inner motivational force powers knowledge transfer. Knowledge transfer from individuals to groups and organization must follow knowledge creation in order to transform individual into organizational knowledge, along the epistemological dimension of the Nonaka’s knowledge dynamics model. Moreover, the knowledge intensive organizations increase their fluxes of knowledge...
Component-Based Technology Transfer in the Presence of Potential Imitators
Jiong Sun; Laurens G. Debo; Sunder Kekre; Jinhong Xie
2010-01-01
Technology transfer to low-cost locations offers global firms an opportunity to reduce their variable costs involved in serving emerging markets. However, such moves may also make imitation by local competitors easier. As a consequence, technology transfer may create competition in the local market. We introduce component-based technology transfer for the global firm as a means to deter or accommodate the imitators' entry, recognizing that components may differ in technological complexity. By...
International Nuclear Information System (INIS)
Graphical abstract: Two trajectories for the collision of a proton with the Lithium tetramer. On the left, the proton is scattered away, and a Li2 molecule plus two isolated Lithium atoms result. On the right, the proton is captured and a LiH molecule is created. Highlights: ► Scattering of a proton with Lithium clusters described from first principles. ► Description based on non-adiabatic molecular dynamics. ► The electronic structure is described with time-dependent density-functional theory. ► The method allows to discern reaction channels depending on initial parameters. - Abstract: We have employed non-adiabatic molecular dynamics based on time-dependent density-functional theory to characterize the scattering behavior of a proton with the Li4 cluster. This technique assumes a classical approximation for the nuclei, effectively coupled to the quantum electronic system. This time-dependent theoretical framework accounts, by construction, for possible charge transfer and ionization processes, as well as electronic excitations, which may play a role in the non-adiabatic regime. We have varied the incidence angles in order to analyze the possible reaction patterns. The initial proton kinetic energy of 10 eV is sufficiently high to induce non-adiabatic effects. For all the incidence angles considered the proton is scattered away, except in one interesting case in which one of the Lithium atoms captures it, forming a LiH molecule. This theoretical formalism proves to be a powerful, effective and predictive tool for the analysis of non-adiabatic processes at the nanoscale.
Yu, Binbin; Zeng, Zhong; Ren, Qinyu; Chen, Yang; Liang, Mei; Zou, Huawei
2016-09-01
A series of block type polycarboxylate-based superplasticizers (PCs) with different molecular architectures were synthesized with macromonomer butenyl alkylene polyoxyethylene-polyoxypropylene ether (BAPP) and acrylic acid (AA) by reversible addition-fragmentation chain transfer (RAFT) polymerization. Fourier-Transformed Infrared (FTIR) Spectroscopy and dynamic light scattering (DLS) were applied to investigate the PCs' molecular structure. The dispersion capacity of the PCs in cement were also measured, and the results showed that the polycarboxylic dispersing agents prepared by this method were suitable for portlant cement. It was found that the PCs could affect the hydration process, which was performed through retarding the generation of ettringite in the hydrated product. Our studies with X-ray diffraction (XRD), scanning electron microscopy (SEM) and compressive strength measurement of hydrated production were all supporting this conclusion.
LabVIEW-based X-ray detection system for laser compton scattering experiment
International Nuclear Information System (INIS)
A LabVIEW-based X-ray detection system has been developed for laser-Compton scattering (LCS) experiments at the 100 MeV Linac of the Shanghai Institute of Applied Physics (SINAP). It mainly consists of a Si (Li) detector, readout electronics and a LabVIEW-based Data Acquisition (DAQ), and possesses the functions of signal spectrum displaying, acquisition control and simple online data analysis and so on Performance tests show that energy and time resolutions of the system are 184 eV (FWHM) at 5.9 keV and ≤1% respectively and system instability is found to be 0.3‰ within a week. As a result, this X-ray detection system has low-cost and high-performance features and can meet the requirements of LCS experiment. (authors)
Lu, Xin; Soto, Marcelo A.; Thévenaz, Luc
2016-05-01
A novel distributed fibre sensing technique is described and experimentally validated, based on birefringence measurements using coherent Rayleigh scattering. It natively provides distributed measurements of temperature and strain with more than an order of magnitude higher sensitivity than Brillouin sensing, and requiring access to a single fibre-end. Unlike the traditional Rayleigh-based coherent optical time-domain reflectometry, this new method provides absolute measurements of the measurand and may lead to a robust discrimination between temperature and strain in combination with another technique. Since birefringence is purposely induced in the fibre by design, large degrees of freedom are offered to optimize and scale the sensitivity to a given quantity. The technique has been validated in 2 radically different types of birefringent fibres - elliptical-core and Panda polarization-maintaining fibres - with a good repeatability.
Yang, Yang; Li, Xiukun
2016-06-01
Separation of the components of rigid acoustic scattering by underwater objects is essential in obtaining the structural characteristics of such objects. To overcome the problem of rigid structures appearing to have the same spectral structure in the time domain, time-frequency Blind Source Separation (BSS) can be used in combination with image morphology to separate the rigid scattering components of different objects. Based on a highlight model, the separation of the rigid scattering structure of objects with time-frequency distribution is deduced. Using a morphological filter, different characteristics in a Wigner-Ville Distribution (WVD) observed for single auto term and cross terms can be simplified to remove any cross-term interference. By selecting time and frequency points of the auto terms signal, the accuracy of BSS can be improved. An experimental simulation has been used, with changes in the pulse width of the transmitted signal, the relative amplitude and the time delay parameter, in order to analyzing the feasibility of this new method. Simulation results show that the new method is not only able to separate rigid scattering components, but can also separate the components when elastic scattering and rigid scattering exist at the same time. Experimental results confirm that the new method can be used in separating the rigid scattering structure of underwater objects.
Pollak, Eli
2016-07-21
This year we celebrate the 80th anniversary of the Landau-Teller model for energy exchange in a collinear collision of an atom with a harmonic diatomic molecule. Even after 80 years though, the analytic theory to date has not included in it the back-influence of the oscillator's motion on the energy transfer between the approaching particle and the molecule. This is the topic of the present paper. The back-influence can be obtained by employing classical second-order perturbation theory. The second-order theory is used in both a classical and semiclassical context. Classically, analytic expressions are derived for the final phase and action of the diatom, after the collision. The energy loss of the atom is shown to decrease linearly with the increasing energy of the oscillator. The magnitude of this decrease is a direct consequence of the back-reaction of the oscillator on the translational motion. The qualitative result is universal, in the sense that it is not dependent on the details of the interaction of the atom with the oscillator. A numerical application to a model collision of an Ar atom with a Br2 diatom demonstrates the importance and accuracy of the second-order perturbation theory. The same results are then used to derive a second-order perturbation theory semiclassical expression for the quantum transition probability from initial vibrational state ni to final vibrational state nf of the oscillator. A comparison of the theory with exact quantum data is presented for a model collision of Br2 with a hydrogen molecule, where the hydrogen molecule is considered as a single approaching particle. PMID:27309793
A light scattering study of the evolution of pairing in Fe-based superconductors
Energy Technology Data Exchange (ETDEWEB)
Hackl, Rudi; Kretzschmar, Florian; Muschler, Bernhard; Boehm, Thomas [Walther-Meissner-Institut, DE-85748 Garching (Germany); Wen, Hai-Hu [Nanjing University, Nanjing 210093 (China); Tsurkan, Vladimir [University of Augsburg, DE-86159 Augsburg (Germany); Academy of Sciences of Moldova, MD-2028 Chisinau (Moldova, Republic of); Deisenhofer, Joachim; Loidl, Alois [University of Augsburg, DE-86159 Augsburg (Germany)
2013-07-01
The iron-based superconductors are a laboratory for exploring the relevance of electron-electron interactions beyond electron-phonon coupling, being at work in conventional superconductors, since the Fermi surfaces can be varied systematically by atomic substitution. This enables one to systematically study magnetism and superconductivity as a function of the Fermi surface topology. Inelastic light scattering affords a window into the electronic properties of the ordered states. In particular, the evolution of the superconducting pairing upon doping can be probed since light scattering allows access to the anisotropy of the energy gap and, in some cases, of the pairing potential. Ba{sub 1-x}K{sub x}Fe{sub 2}As{sub 2} is one of those cases since the competition between s- and d-wave pairing leads to the appearance of exciton-like modes below the gap edges of the various bands. Along with the results from other materials having different Fermi surface cross-sections the data in Ba{sub 1-x}K{sub x}Fe{sub 2}As{sub 2} support the spin fluctuation scenario driven by interband coupling. The experiments show that there exist alternative routes for the analysis of the pairing interaction in superconductors with unconventional coupling and anisotropic gaps.
Wang, Houyu; Jiang, Xiangxu; He, Yao
2016-08-15
During the past few decades, thanks to silicon nanomaterials' outstanding electronic/optical/mechanical properties, large surface-to-volume ratio, abundant surface chemistry, facile tailorability and good compatibility with modern semiconductor industry, different dimensional silicon nanostructures have been widely employed for rationally designing and fabricating high-performance surface-enhanced Raman scattering (SERS) sensors for the detection of various chemical and biological species. Among these, two-dimensional silicon nanostructures made of metal nanoparticle-modified silicon wafers and three-dimensional silicon nanostructures made of metal nanoparticle-decorated SiNW arrays are of particular interest, and have been extensively exploited as promising silicon-based SERS-active substrates for the construction of high-performance SERS sensors. With an aim to retrospect these important and exciting achievements, we herein focus on reviewing recent representative studies on silicon-based SERS sensors for sensing applications from a broad perspective and possible future direction, promoting readers' awareness of these novel powerful silicon-based SERS sensing technologies. Firstly, we summarize the two unique merits of silicon-based SERS sensors, and those are high sensitivity and good reproducibility. Next, we present recent advances of two- and three-dimensional silicon-based SERS sensors, especially for real applications. Finally, we discuss the major challenges and prospects for the development of silicon-based SERS sensors. PMID:27414500
Biclustering of Gene Expression Data by Correlation-Based Scatter Search
Directory of Open Access Journals (Sweden)
Nepomuceno Juan A
2011-01-01
Full Text Available Abstract Background The analysis of data generated by microarray technology is very useful to understand how the genetic information becomes functional gene products. Biclustering algorithms can determine a group of genes which are co-expressed under a set of experimental conditions. Recently, new biclustering methods based on metaheuristics have been proposed. Most of them use the Mean Squared Residue as merit function but interesting and relevant patterns from a biological point of view such as shifting and scaling patterns may not be detected using this measure. However, it is important to discover this type of patterns since commonly the genes can present a similar behavior although their expression levels vary in different ranges or magnitudes. Methods Scatter Search is an evolutionary technique that is based on the evolution of a small set of solutions which are chosen according to quality and diversity criteria. This paper presents a Scatter Search with the aim of finding biclusters from gene expression data. In this algorithm the proposed fitness function is based on the linear correlation among genes to detect shifting and scaling patterns from genes and an improvement method is included in order to select just positively correlated genes. Results The proposed algorithm has been tested with three real data sets such as Yeast Cell Cycle dataset, human B-cells lymphoma dataset and Yeast Stress dataset, finding a remarkable number of biclusters with shifting and scaling patterns. In addition, the performance of the proposed method and fitness function are compared to that of CC, OPSM, ISA, BiMax, xMotifs and Samba using Gene the Ontology Database.
Evaluation of property scatter of Ni-base alloy in 738 LC
International Nuclear Information System (INIS)
Highlights: → Correlation between chemical composition and position in scatter band. → Substantial influence of micro porosity. → Hot isostatic pressing (HIP) reduces scatter significantly. → Property scatter diminishes with rising temperature. - Abstract: In high temperature creep testing the conventionally cast alloy IN 738 LC exhibits a comparably large property scatter which requires high safety margins in design and dimensioning and subsequently causes an incomplete exploitation of the materials potential. The reasons for this property scatter were investigated and traced back to different influencing factors. Parallel to investigations on the microstructure of post-exposure material and conventional scatter band analysis, artificial neural networks were successfully applied to discover relations between the chemical composition of the individual melt and the position of the corresponding test results within the global scatter band.
International Nuclear Information System (INIS)
Geophysical bore-hole data represent the physical properties of rocks, such as density and formation lithology, as a function of depth in a well. Properties of rocks are obtained from gamma ray transport logs. Transport of gamma rays, from a 137Cs point gamma source situated in a bore-hole tool, through rock media to detectors, has been simulated using a GEANT4 radiation transport code. The advanced Compton scattering concepts were used to gain better analyses about well formation. The simulation and understanding of advanced Compton scattering highly depends on how accurately the effects of Doppler broadening and Rayleigh scattering are taken into account. A Monte Carlo package that simulates the gamma-gamma well logging tools based on GEANT4 advanced low energy Compton scattering (GALECS).
S.V. Naidu; V. Dharma Rao; B. Govinda Rao; A. Sombabu; B. Sreenivasulu
2010-01-01
The problem of natural convection heat transfer from fin arrays with inclination is studied experimentally and theoretically to find the effect of inclination of the base of the fin array on heat transfer rate. A numerical model is developed by taking an enclosure, which is formed by two adjacent vertical fins and horizontal base. Results obtained from this enclosure are used to predict heat transfer rate from the fin array. All the governing equations related to fluid in the enclosure, toget...
International Nuclear Information System (INIS)
Quantal and semi-classical methods have been used to investigate slow electron, ionic and molecular collisions. Three distinct areas have been considered: the elastic scattering of electrons from positive ions, the symmetric resonance charge transfer in one-electron ion-ion collisions and the mutual neutralization of the hydrogen molecular ion and the negative hydrogen or deuterium ion. Differential cross sections for the elastic scattering of electrons from the closed-shell ions Na+, Cs+, Mg2+, N3+ and Ar8+ were obtained employing model and psuedopotential and quantum defect methods in a partial-wave analysis. Results were found to be consistent with recent experiments (Williams 1999 Rep. Prog. Phys. 62 1431) for Na+ and N3+, but less good agreement was obtained for Cs+ and Ar8+. The symmetric resonance charge transfer reaction AZ+ + A(Z-1)+ (1s) → A(Z-1)+ (1s) + AZ+ with Z > 1 has been investigated. In particular, differential cross sections for charge transfer in the 4He+-3He2+ system were determined in the perturbed stationary states approximation. These two-state semi-classical calculations were found to be in excellent agreement with fully quantal calculations of Falcon (1983 J. Phys. B: At. Mol. Phys. 16 1793), and in reasonable agreement with calculations and experiment of Kruedener et al (1997 Phys.Rev. Lett. 79 1002). Total cross sections for this and iso-electronic systems were found to agree with simple approximations. Total cross sections for the mutual neutralization reaction H2+ + D- → H2(1s, nl) + D(1s) + Δε were found using the Landau-Zener curve-crossing model. This method of calculation is heavily dependent on the reliability of estimates of the coupling matrix elements. Potential energy curves for the H2 molecule were found using the MOLPRO package in order to have a consistent base from which to determine the energetics of the reaction. Agreement with early experiments of Aberth et al (1971 AFCRL Report No. 71-0481 Bedford, Mass.) is
EFFECTS OF EXAMPLE-PROBLEM BASED LEARNING ON TRANSFER PERFORMANCE IN CIRCUIT THEORY
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Noor Hisham Jalani
2014-12-01
Full Text Available The main goal of the study was to test a hypothesis that Example-Problem-Based Learning (EPBL would lead to better transfer performance compared Traditional Learning (TL approach. The participants were vocational diploma-level students and the learning domain was Circuit Theory. As a means of data collection, 10-items open-ended test (five items each for assessing near-transfer and far-transfer was administered as a pre-test and post-test. A sufficient reliability estimate was obtained, a= 0.74, based on the Cronbach Alpha method. A statistically significant difference on the post test score was observed between the EPBL and the TL group where the EPBL group scored higher than the TL group on both near and far-transfer. In conclusion, EPBL approaches produces greater learning compared to TL approach, for both near and distant-transfer.
International Nuclear Information System (INIS)
We briefly review some of the motivations, early results, and techniques of magnetic elastic and inelastic electron-nucleus scattering. We then discuss recent results, especially those acquired at high momentum transfers. 50 refs., 19 figs
Branchini, Bruce
2016-01-01
We describe here the preparation of ratiometric luminescent probes that contain two well-separated emission peaks produced by a sequential bioluminescence resonance energy transfer (BRET)-fluorescence resonance energy transfer (FRET) process. The probes are single soluble fusion proteins consisting of a thermostable firefly luciferase variant that catalyzes yellow-green (560 nm maximum) bioluminescence and a red fluorescent protein covalently labeled with a near-Infrared fluorescent dye. The two proteins are connected by a decapeptide containing a protease recognition site specific for factor Xa, thrombin, or caspase 3. The rates of protease cleavage of the fusion protein substrates were monitored by recording emission spectra and plotting the change in peak ratios over time. Detection limits of 0.41 nM for caspase 3, 1.0 nM for thrombin, and 58 nM for factor Xa were realized with a scanning fluorometer. This method successfully employs an efficient sequential BRET-FRET energy transfer process based on firefly luciferase bioluminescence to assay physiologically important protease activities and should be generally applicable to the measurement of any endoprotease lacking accessible cysteine residues. PMID:27424898
Dynamics in poly vinyl alcohol (PVA) based hydrogel: Neutron scattering study
International Nuclear Information System (INIS)
Results of quasielastic neutron scattering measurements carried out on Poly Vinyl Alcohol (PVA) based hydrogels are reported here. PVA hydrogels are formed using Borax as a cross-linking agent in D2O solvent. This synthetic polymer can be used for obtaining the hydrogels with potential use in the field of biomaterials. The aim of this paper is to study the dynamics of polymer chain in the hydrogel since it is known that polymer mobility influences the kinetics of loading and release of drugs. It is found that the dynamics of hydrogen atoms in the polymer chain could be described by a model where the diffusion of hydrogen atoms is limited within a spherical volume of radius 3.3 Å. Average diffusivity estimated from the behavior of quasielastic width is found to be 1.2 × 10−5 cm2/sec
An efficient solver for volumetric scattering based on fast spherical harmonics transforms
Han, Youngae
2012-01-01
The Helmholtz equation arises in the study of electromagnetic radiation, optics, acoustics, etc. In spherical coordinates, its general solution can be written as a spherical harmonic series which satisfies the radiation condition at infinity, ensuring that the wave is outgoing. The boundary condition at infinity is hard to enforce with a finite element method since a suitable approximation needs to be made within reasonable distance from scatterers. Luckily, the Helmholtz equation can be represented as a Lippmann-Schwinger integral equation which removes the necessity of the boundary approximations and its Green's function can be expanded as a spherical harmonic series which leads to our numerical scheme based on spherical harmonic polynomial transform. In this paper, we present an efficient solver for the Helmholtz equation which costs $O(N\\log N)$ operations, where $N$ is the number of the discretization points. We use the fast spherical harmonic transforms which are originally developed in \\cite{suda}. The...
Zhang, Fang; Zheng, Yonghong; Liang, Jiaman; Long, Sha; Chen, Xianping; Tan, Kejun
2016-04-01
A simple, highly sensitive resonance light scattering (RLS) method for the detection of perfluorooctanoic acid (PFOA) has been developed based on the interaction with crystal violet (CV). It was found that PFOA can form complexes with CV in acid medium resulting in remarkable enhancement of the RLS intensity of the system. And the enhanced RLS intensities are in proportion to the concentration of PFOA in the range of 0.1-25.0 μmol/L (R2 = 0.9998), with a detection limit of 11.0 nmol/L (S/N = 3). In this work, the optimum reaction conditions and the interferences of foreign substances were investigated. The reaction mechanism between CV and PFOA was also studied by the absorption spectrum and scanning electron microscope (SEM). This method is successfully applied to the determination of PFOA in tap water and Jialing river water samples with RSD ≤ 4.04%.
International Nuclear Information System (INIS)
We have developed a novel resonance light scattering (RLS) assay for the sensitive and selective determination of iodide. It is based on the use of histidine-stabilized gold nanoclusters (His-AuNCs) which undergo fusion and aggregation in the presence of iodide. The resulting enhancement in the intensity of RLS is proportional to the concentration of iodide in the 0.01 to 8.0 μM range, and the detection limit is as low as 1.8 nM at a signal-to-noise ratio of 3. This “turn-on” method is highly selective for iodide and not interfered by other ions commonly present. It was applied to the determination of iodide in (spiked) real water samples. (author)
Photoacoustic blood glucose and skin measurement based on optical scattering effect
Zhao, Zuomin; Myllyla, Risto A.
2002-07-01
Non-invasive blood glucose determination has been investigated by more than 100 research groups in the world during the past fifteen years. The commonly optical methods are based on the capacity of near-IR light to penetrate a few hundreds micrometers or a few millimeters into human tissue where it interacts with glucose. A change of glucose concentration may modify the optical parameters in tissue, with the result that its glucose concentration can be extracted by analyzing the received optical signals. This paper demonstrates that glucose affects on the scattering coefficient of human blood, by applying the streak camera and pulsed photoacoustic techniques; and drinking water seems also affecting on PA signal from skin surface.
Directory of Open Access Journals (Sweden)
Xiaoqiao Deng
2013-01-01
Full Text Available The fast dipole method (FDM is extended to analyze the scattering of dielectric and magnetic materials by solving the volume integral equation (VIE. The FDM is based on the equivalent dipole method (EDM and can achieve the separation of the field dipole and source dipole, which reduces the complexity of interactions between two far groups (such as group i and group j from O(NiNj to O(Ni+Nj, where Ni and Nj are the numbers of dipoles in group i and group j, respectively. Targets including left-handed materials (LHMs, which are a kind of dielectric and magnetic materials, are calculated to demonstrate the merits of the FDM. Furthermore, in this study we find that the convergence may become much slower when the targets include LHMs compared with conventional electromagnetic materials. Numerical results about convergence characteristics are presented to show this property.
Intense X-ray sources based on compton scattering in laser electron storage rings
International Nuclear Information System (INIS)
The main problem of the designing of intense X-ray sources based on Compton scattering in laser-electron storage ring is associated with large steady-state electron beam energy spread. In paper the principles of the development of compact storage ring lattice with large RF-acceptance and negligible chromatic effects at interaction point are considered. The storage ring with electron beam energy over the range 100-400 MeV that allows generating intense VUV from bending magnets, X-ray up to 280 keV with rate up to 1014 photons/s and γ-beam up to 2.8 MeV for neutron generation on beryllium target is proposed
Dynamics in poly vinyl alcohol (PVA) based hydrogel: Neutron scattering study
Energy Technology Data Exchange (ETDEWEB)
Prabhudesai, S. A., E-mail: swapnil@barc.gov.in; Mitra, S.; Mukhopadhyay, R. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 40085 (India); Lawrence, Mathias B. [Department of Physics, St. Xavier’s College, Mapusa, Goa 403507 (India); Desa, J. A. E. [Department of Physics, Goa University, Taleigao Plateau, Goa 403206 (India)
2015-06-24
Results of quasielastic neutron scattering measurements carried out on Poly Vinyl Alcohol (PVA) based hydrogels are reported here. PVA hydrogels are formed using Borax as a cross-linking agent in D{sub 2}O solvent. This synthetic polymer can be used for obtaining the hydrogels with potential use in the field of biomaterials. The aim of this paper is to study the dynamics of polymer chain in the hydrogel since it is known that polymer mobility influences the kinetics of loading and release of drugs. It is found that the dynamics of hydrogen atoms in the polymer chain could be described by a model where the diffusion of hydrogen atoms is limited within a spherical volume of radius 3.3 Å. Average diffusivity estimated from the behavior of quasielastic width is found to be 1.2 × 10{sup −5} cm{sup 2}/sec.
MIDAS-W: a workstation-based incoherent scatter radar data acquisition system
Directory of Open Access Journals (Sweden)
J. M. Holt
Full Text Available The Millstone Hill Incoherent Scatter Data Acquisition System (MIDAS is based on an abstract model of an incoherent scatter radar. This model is implemented in a hierarchical software system, which serves to isolate hardware and low-level software implementation details from higher levels of the system. Inherent in this is the idea that implementation details can easily be changed in response to technological advances. MIDAS is an evolutionary system, and the MIDAS hardware has, in fact, evolved while the basic software model has remained unchanged. From the earliest days of MIDAS, it was realized that some functions implemented in specialized hardware might eventually be implemented by software in a general-purpose computer. MIDAS-W is the realization of this concept. The core component of MIDAS-W is a Sun Microsystems UltraSparc 10 workstation equipped with an Ultrarad 1280 PCI bus analog to digital (A/D converter board. In the current implementation, a 2.25 MHz intermediate frequency (IF is bandpass sampled at 1 µs intervals and these samples are multicast over a high-speed Ethernet which serves as a raw data bus. A second workstation receives the samples, converts them to filtered, decimated, complex baseband samples and computes the lag-profile matrix of the decimated samples. Overall performance is approximately ten times better than the previous MIDAS system, which utilizes a custom digital filtering module and array processor based correlator. A major advantage of MIDAS-W is its flexibility. A portable, single-workstation data acquisition system can be implemented by moving the software receiver and correlator programs to the workstation with the A/D converter. When the data samples are multicast, additional data processing systems, for example for raw data recording, can be implemented simply by adding another workstation with suitable software to the high-speed network. Testing of new data processing software is also greatly
MIDAS-W: a workstation-based incoherent scatter radar data acquisition system
Holt, J. M.; Erickson, P. J.; Gorczyca, A. M.; Grydeland, T.
2000-09-01
The Millstone Hill Incoherent Scatter Data Acquisition System (MIDAS) is based on an abstract model of an incoherent scatter radar. This model is implemented in a hierarchical software system, which serves to isolate hardware and low-level software implementation details from higher levels of the system. Inherent in this is the idea that implementation details can easily be changed in response to technological advances. MIDAS is an evolutionary system, and the MIDAS hardware has, in fact, evolved while the basic software model has remained unchanged. From the earliest days of MIDAS, it was realized that some functions implemented in specialized hardware might eventually be implemented by software in a general-purpose computer. MIDAS-W is the realization of this concept. The core component of MIDAS-W is a Sun Microsystems UltraSparc 10 workstation equipped with an Ultrarad 1280 PCI bus analog to digital (A/D) converter board. In the current implementation, a 2.25 MHz intermediate frequency (IF) is bandpass sampled at 1 µs intervals and these samples are multicast over a high-speed Ethernet which serves as a raw data bus. A second workstation receives the samples, converts them to filtered, decimated, complex baseband samples and computes the lag-profile matrix of the decimated samples. Overall performance is approximately ten times better than the previous MIDAS system, which utilizes a custom digital filtering module and array processor based correlator. A major advantage of MIDAS-W is its flexibility. A portable, single-workstation data acquisition system can be implemented by moving the software receiver and correlator programs to the workstation with the A/D converter. When the data samples are multicast, additional data processing systems, for example for raw data recording, can be implemented simply by adding another workstation with suitable software to the high-speed network. Testing of new data processing software is also greatly simplified, because a
Imaging with Scattered Neutrons
Ballhausen, H.; Abele, H.; Gaehler, R.; Trapp, M; Van Overberghe, A.
2006-01-01
We describe a novel experimental technique for neutron imaging with scattered neutrons. These scattered neutrons are of interest for condensed matter physics, because they permit to reveal the local distribution of incoherent and coherent scattering within a sample. In contrast to standard attenuation based imaging, scattered neutron imaging distinguishes between the scattering cross section and the total attenuation cross section including absorption. First successful low-noise millimeter-re...
Software-Based Wireless Power Transfer Platform for Various Power Control Experiments
Sun-Han Hwang; Chung G. Kang; Yong-Ho Son; Byung-Jun Jang
2015-01-01
In this paper, we present the design and evaluation of a software-based wireless power transfer platform that enables the development of a prototype involving various open- and closed-loop power control functions. Our platform is based on a loosely coupled planar wireless power transfer circuit that uses a class-E power amplifier. In conjunction with this circuit, we implement flexible control functions using a National Instruments Data Acquisition (NI DAQ) board and algorithms in the MATLAB/...
Game based learning for 21st century transferable skills: challenges and opportunities
Bellotti, Francesco; Bottino, Rosa Maria; Nadolski, Rob; Fernández Manjón, Baltasar
2012-01-01
Bellotti, F., Bottino, R. M., Nadolski, R. J., & Fernández Manjón, B. (2012, 4-6 July). Game based learning for 21st century transferable skills: challenges and opportunities. Presentation at the Workshop Game based learning for 21st century transferable skills: challenges and opportunities, 12th IEEE International Conference on Advanced Learning Technologies (ICALT 2012), Rome, Italy: IEEE Computer Society CPS.
Wireless power transfer based on magnetic quadrupole coupling in dielectric resonators
Song, Mingzhao; Iorsh, Ivan; Kapitanova, Polina; Nenasheva, Elizaveta; Belov, Pavel
2016-01-01
We numerically investigate a magnetic resonant wireless power transfer system based on high refractive index dielectric resonators. We propose to operate at magnetic quadrupole mode of the resonators to enlarge the efficiency due to minimization of ohmic and radiation losses. Numerical estimation predicts the 80% efficiency of the wireless power transfer (WPT) system operating at quadrupole mode at 300 MHz. Moreover, the system operating at magnetic quadrupole mode is capable of transferring power with 70% efficiency when the receiver rotates 90°. We verify the simulated results by experimental investigation of the WPT system based on microwave ceramic resonators (ɛ = 80 and tanδ = 10-4).
Obeid, A Scheikh; Chernykh, M; Krugmann, A; von Neumann-Cosel, P; Pietralla, N; Poltoratska, I; Ponomarev, V Yu; Walz, C
2012-01-01
Background: Mixed-symmetry 2+ states in vibrational nuclei are characterized by a sign change between dominant proton and neutron valence-shell components with respect to the fully symmetric 2+ state. The sign can be measured by a decomposition of proton and neutron transition radii with a combination of inelastic electron and hadron scattering [C. Walz et al., Phys. Rev. Lett. 106, 062501 (2011)]. For the case of 92Zr, a difference could be experimentally established for the neutron components, while about equal proton transition radii were indicated by the data. Method: Differential cross sections for the excitation of one-phonon 2+ and 3- states in 92Zr have been measured with the (e,e') reaction at the S-DALINAC in a momentum transfer range q = 0.3-0.6 fm^(-1). Results: Transition strengths B(E2;2+_1 -> 0+_1) = 6.18(23), B(E2; 2+_2 -> 0+_1) = 3.31(10) and B(E3; 3-_1 -> 0+_1) = 18.4(11) Weisskopf units are determined from a comparison of the experimental cross sections to quasiparticle-phonon model (QPM) c...
Energy Technology Data Exchange (ETDEWEB)
Charalampous, Georgios; Hardalupas, Yannis
2011-03-20
The dependence of fluorescent and scattered light intensities from spherical droplets on droplet diameter was evaluated using Mie theory. The emphasis is on the evaluation of droplet sizing, based on the ratio of laser-induced fluorescence and scattered light intensities (LIF/Mie technique). A parametric study is presented, which includes the effects of scattering angle, the real part of the refractive index and the dye concentration in the liquid (determining the imaginary part of the refractive index). The assumption that the fluorescent and scattered light intensities are proportional to the volume and surface area of the droplets for accurate sizing measurements is not generally valid. More accurate sizing measurements can be performed with minimal dye concentration in the liquid and by collecting light at a scattering angle of 60 deg. rather than the commonly used angle of 90 deg. Unfavorable to the sizing accuracy are oscillations of the scattered light intensity with droplet diameter that are profound at the sidescatter direction (90 deg.) and for droplets with refractive indices around 1.4.
International Nuclear Information System (INIS)
The dependence of fluorescent and scattered light intensities from spherical droplets on droplet diameter was evaluated using Mie theory. The emphasis is on the evaluation of droplet sizing, based on the ratio of laser-induced fluorescence and scattered light intensities (LIF/Mie technique). A parametric study is presented, which includes the effects of scattering angle, the real part of the refractive index and the dye concentration in the liquid (determining the imaginary part of the refractive index). The assumption that the fluorescent and scattered light intensities are proportional to the volume and surface area of the droplets for accurate sizing measurements is not generally valid. More accurate sizing measurements can be performed with minimal dye concentration in the liquid and by collecting light at a scattering angle of 60 deg. rather than the commonly used angle of 90 deg. Unfavorable to the sizing accuracy are oscillations of the scattered light intensity with droplet diameter that are profound at the sidescatter direction (90 deg.) and for droplets with refractive indices around 1.4.
Evaluation of simulation-based scatter correction for 3-D PET cardiac imaging
International Nuclear Information System (INIS)
Quantitative imaging of the human thorax poses one of the most difficult challenges for three-dimensional (3-D) (septaless) positron emission tomography (PET), due to the strong attenuation of the annihilation radiation and the large contribution of scattered photons to the data. In [18F] fluorodeoxyglucose (FDG) studies of the heart with the patient's arms in the field of view, the contribution of scattered events can exceed 50% of the total detected coincidences. Accurate correction for this scatter component is necessary for meaningful quantitative image analysis and tracer kinetic modeling. For this reason, the authors have implemented a single-scatter simulation technique for scatter correction in positron volume imaging. In this paper they describe this algorithm and present scatter correction results from human and chest phantom studies
X-ray Raman scattering with Bragg diffraction in a La-based superlattice
André, Jean-Michel; Jonnard, Philippe; Bonnelle, Christiane; O. Filatova, E.; Michaelsen, C.; Wiesmann, J
2005-01-01
11 pages The non-dispersed soft x-ray emission from a La/B4C periodic multilayer irradiated by monochromatic x-rays has been measured as a function of the incident photon energy in the 125-200 eV range for different scattering angles. We have observed a scattered intensity peak at incident energies which shift towards the low-energy side as the value of the scattering angle increases. These observations are interpreted as Raman scattering by the 5p level of lanthanum assisted by Bragg diff...
International Nuclear Information System (INIS)
A modified finite-volume method based on a cell vertex scheme was applied to solve radiative transfer problems within a participating medium of complex three-dimensional shaped domain. The computational spatial domain of interest was divided into four-node tetrahedron elements with unstructured meshes while the adopted formulation was combined with a closure relation based on an exponential scheme. The studied medium was assumed to be grey, non-scattering and was bounded by black surfaces. Our results were then compared with those found in other articles on the subject. The approach shows a very good level of performance for wall heat transfer evaluation. Accurate results were obtained on coarse computational meshes and solution errors were found to decrease with grid refinement.
Knowledge-based process control and diagnostics for orbital cryogen transfer
Raymond, Eric A.
1989-01-01
AFDex is a rule based system designed to provide intelligent process control, diagnosis, and error recovery for a Shuttle based cryogenic experiment, SHOOT (Superfluid Helium On-Orbit Transfer). This paper describes the AFDex system in the context of traditional associative, model-based, and qualitative systems and discusses the implications of this first expert system in space.
International Nuclear Information System (INIS)
Optical tomography (OT) is a promising non-intrusive characterization technique of absorbing and scattering media that uses transmitted and/or reflected signals of samples irradiated with visible or near-infrared light. The quality of OT techniques is directly related to the accuracy of their forward models due to the use of inversion algorithms. In this paper, forward models for transient OT approaches are investigated. The system under study involves a one-dimensional absorbing and scattering medium illuminated by a short laser pulse; this problem is solved using a discrete ordinates-finite volume (DO-FV) method in both time and frequency domain. Previous works have shown that time-domain approaches coupled with first order spatial interpolation schemes cannot represent the physics of the problem adequately as transmitted fluxes emerge before the minimal physical time required to leave the medium. In this work, the Van Leer and Superbee flux limiters, combined with the second order Lax-Wendroff scheme, are used in an attempt to prevent this. Results show that despite significant improvement, flux limiters fail to completely eliminate the physically unrealistic behaviour. On the other hand, results for transmittance obtained from the frequency-based method are accurate, without physically unrealistic behaviours at early time periods. The frequency-dependent approach is however computationally expensive, since it requires approximately five times more computational time than its temporal counterpart when used as a forward model for transient OT. On the other hand, the great advantages of the frequency-based approach is that limited windows of temporal signals can be calculated efficiently (in transient OT), and it can also be used as a forward model for steady-state, frequency-based and transient OT techniques
International Nuclear Information System (INIS)
The thermal neutron scattering cross sections of ZrHx are heavily affected by the solid frequency distributions, also called “phonon spectra”, of Zr and H in ZrHx. Although the phonon spectra vary for different x in ZrHx, current reference data, e.g. ENDF, are based on ZrH2. This may introduce non-negligible errors in the simulations for TRIGA reactors. In the previous work, we have proposed parameterized phonon spectrum (PPS) models to explore the effects of changing the spectra by varying the parameters and investigated the effects on reactivity and fuel fission rate density on TRIGA lattice model. In this work, we extend the analyses to quantities of interest (QOIs) on the realistic full-core geometry of the TRIGA reactor at Texas A and M University. In this work, we sampled the parameters with Latin Hypercube sampling designs (LHS) in a novel way and generated corresponding phonon spectra. NJOY and MCNP were used to carry out the calculations. We investigated reactivity (ρ), neutron mean generation time (Λ), fuel temperature feedback coefficient αTFuel(293.6 - 600 K) and ex-core/in-core detector reaction rates. Statistical analyses indicate ρ, Λ and αTFuel are sensitive to the parameters while other QOIs are not. We calibrated the parameters for ENDF-VII as a surrogate for experimental data. Results show the feasibility of the parameter calibrations. Future work will perform experiments to archive QOIs and to calibrate the parameters in the PPS model to generate thermal scattering cross sections used in future simulations. (author)
Yang, C. H.; Kenduiywo, B. K.; Soergel, U.
2016-06-01
Persistent Scatterer Interferometry (PSI) is a technique to detect a network of extracted persistent scatterer (PS) points which feature temporal phase stability and strong radar signal throughout time-series of SAR images. The small surface deformations on such PS points are estimated. PSI particularly works well in monitoring human settlements because regular substructures of man-made objects give rise to large number of PS points. If such structures and/or substructures substantially alter or even vanish due to big change like construction, their PS points are discarded without additional explorations during standard PSI procedure. Such rejected points are called big change (BC) points. On the other hand, incoherent change detection (ICD) relies on local comparison of multi-temporal images (e.g. image difference, image ratio) to highlight scene modifications of larger size rather than detail level. However, image noise inevitably degrades ICD accuracy. We propose a change detection approach based on PSI to synergize benefits of PSI and ICD. PS points are extracted by PSI procedure. A local change index is introduced to quantify probability of a big change for each point. We propose an automatic thresholding method adopting change index to extract BC points along with a clue of the period they emerge. In the end, PS ad BC points are integrated into a change detection image. Our method is tested at a site located around north of Berlin main station where steady, demolished, and erected building substructures are successfully detected. The results are consistent with ground truth derived from time-series of aerial images provided by Google Earth. In addition, we apply our technique for traffic infrastructure, business district, and sports playground monitoring.
Pedestrian movement analysis in transfer station corridor: Velocity-based and acceleration-based
Ji, Xiangfeng; Zhang, Jian; Hu, Yongkai; Ran, Bin
2016-05-01
In this paper, pedestrians are classified into aggressive and conservative ones by their temper. Aggressive pedestrians' walking through crowd in transfer station corridor is analyzed. Treating pedestrians as particles, this paper uses the modified social force model (MSFM) as the building block, where forces involve self-driving force, repulsive force and friction force. The proposed model in this paper is a discrete model combining the MSFM and cellular automata (CA) model, where the updating rules of the CA are redefined with MSFM. Due to the continuity of values generated by the MSFM, we use the fuzzy logic to discretize the continuous values into cells pedestrians can move in one step. With the observation that stimulus around pedestrians influences their acceleration directly, an acceleration-based movement model is presented, compared to the generally reviewed velocity-based movement model. In the acceleration-based model, a discretized version of kinematic equation is presented based on the acceleration discretized with fuzzy logic. In real life, some pedestrians would rather keep their desired speed and this is also mimicked in this paper, which is called inertia. Compared to the simple triangular membership function, a trapezoidal membership function and a piecewise linear membership function are used to capture pedestrians' inertia. With the trapezoidal and the piecewise linear membership function, many overlapping scenarios should be carefully handled and Dubois and Prade's four-index method is used to completely describe the relative relationship of fuzzy quantities. Finally, a simulation is constructed to demonstrate the effect of our model.
Scattering Solar Thermal Concentrators
Energy Technology Data Exchange (ETDEWEB)
Giebink, Noel C. [Pennsylvania State Univ., State College, PA (United States)
2015-01-31
This program set out to explore a scattering-based approach to concentrate sunlight with the aim of improving collector field reliability and of eliminating wind loading and gross mechanical movement through the use of a stationary collection optic. The approach is based on scattering sunlight from the focal point of a fixed collection optic into the confined modes of a sliding planar waveguide, where it is transported to stationary tubular heat transfer elements located at the edges. Optical design for the first stage of solar concentration, which entails focusing sunlight within a plane over a wide range of incidence angles (>120 degree full field of view) at fixed tilt, led to the development of a new, folded-path collection optic that dramatically out-performs the current state-of-the-art in scattering concentration. Rigorous optical simulation and experimental testing of this collection optic have validated its performance. In the course of this work, we also identified an opportunity for concentrating photovoltaics involving the use of high efficiency microcells made in collaboration with partners at the University of Illinois. This opportunity exploited the same collection optic design as used for the scattering solar thermal concentrator and was therefore pursued in parallel. This system was experimentally demonstrated to achieve >200x optical concentration with >70% optical efficiency over a full day by tracking with <1 cm of lateral movement at fixed latitude tilt. The entire scattering concentrator waveguide optical system has been simulated, tested, and assembled at small scale to verify ray tracing models. These models were subsequently used to predict the full system optical performance at larger, deployment scale ranging up to >1 meter aperture width. Simulations at an aperture widths less than approximately 0.5 m with geometric gains ~100x predict an overall optical efficiency in the range 60-70% for angles up to 50 degrees from normal. However, the
Nuclear burst detection information transfers system based on BD Navigation
International Nuclear Information System (INIS)
The article introduces the character of BD Navigation System.The feasibility of using BD Navigation System is analyzed. Nuclear explosion information transmission system based on BD Navigation System is designed and implemented. (authors)
Atmospheric Radiative Transfer
Perliski, Lori
Because radiative transfer cuts across many scientific disciplines with applications including remote sensing, climate, atmospheric chemistry, and photobiology, there is a need for comprehensive books on this subject that can appeal to a wide readership. While Atmospheric Radiative Transfer takes strides toward filling this niche by addressing a broad range of topics, it is dry reading and suffers from lack of detail. The book was based on a graduate-level course taught at the University of Sciences and Technologies in Lille, France, and indeed, the text reads much like an expanded outline perhaps derived from lecture notes.Part one deals with general radiative transfer, and part two covers Earth's radiation budget, the climate system, and remote sensing techniques. The radiative transfer equation and solutions for absorbing and scattering atmospheres are discussed as are the details of absorption, such as energy levels, line strengths, line intensities, equivalent widths, and weak- and strong-line limits.
Distant and wide range wireless power transfer from metamedia
Zhu, Lin; Luo, Xudong; Ma, Hongru
2016-07-01
Based on electromagnetic scattering theory, a model of superscatterer enhanced distant wireless power transfer (WPT) device has designed and analyzed with the concept of transformation optics. The numerical results obtained through a series expansion method reveal that a properly designed ss-WPT has high efficiency for long transfer distances as well as a wide transfer range. The transfer distance can be further enlarged by fine tuning of the design. These effects can be explained qualitatively through the study of magnetic flux.
Multiple scattering of ultrasound in weakly inhomogeneous media: application to human soft tissues
Aubry, Alexandre
2010-01-01
Waves scattered by a weakly inhomogeneous random medium contain a predominant single scattering contribution as well as a multiple scattering contribution which is usually neglected, especially for imaging purposes. We propose a method, based on random matrix theory, in order to separate the single and multiple scattering contributions. The experimental set up uses an array of programmable sources/receivers placed in front of the medium. The impulse responses between every couple of transducers are measured and form a matrix. Single-scattering contributions are shown to exhibit a deterministic coherence along the antidiagonals of the array response matrix, whatever the distribution of inhomogeneities. This property is taken advantage of to discriminate single from multiple-scattered waves. This allows one to evaluate the absorption losses and the scattering losses separately, by comparing the multiple scattering intensity with a radiative transfer model. Moreover, the relative contribution of multiple scatter...
Exceptional photosensitivity of a polyoxometalate-based charge-transfer hybrid material.
Liao, Jian-Zhen; Wu, Chen; Wu, Xiao-Yuan; Deng, Shui-Quan; Lu, Can-Zhong
2016-05-31
An unusual room-temperature light sensitivity was realized in a polyoxometalate-based hybrid material due to cooperative multicomponent molecular charge-transfer interactions taking place in this material, mainly among POMs, NDIs, and other molecules. The functional π-acidic NDI linkers and POM clusters in the discussed hybrid material were individually designed as photosensors and electron reservoirs. To propose a photo-induced charge-transfer mechanism, EPR, XPS, UV-Vis and computational studies were carried out, and indicated the presence of active charge-transfer interactions among several of the components. PMID:27192943
Transfer of Trust in Event-based Reputation Systems
DEFF Research Database (Denmark)
Nielsen, Mogens; Krukow, Karl
2012-01-01
terms of evidence of future behaviour based on interactions in the past with its environment. We have previously argued how concepts and models from concurrency theory can answer some fundamental challenges in the representation of such interaction behaviour over time, using event structures as our...
Development of an optical biosensor based on surface-enhanced Raman scattering for DNA analysis
Yigit, Tugce; Akdogan, Ebru; Karagoz, Isık. Didem; Kahraman, Mehmet
2016-03-01
Rapid, accurate and sensitive DNA analysis is critically important for the diagnostic of genetic diseases. The most common method preferred in practice is fluorescence based microarrays to analyze the DNA. However, there exist some disadvantages related to the above-mentioned method such as the overlapping of the fluorescence emission wavelengths that can diminish in the performance of multiplexing, needed to obtain fluorescence spectra from each dye and photo degradation. In this study, a novel SERS based DNA analysis approach, which is Raman active dye-free and independent of SERS substrate properties, is developed. First, the single strand DNA probe is attached to the SERS substrate and half of the complimentary DNA is attached to gold nanoparticles, as well. We hypothesize that in the presence of target DNA, the complimentary DNA coupled colloids will bind to the SERS substrate surface via hybridization of single strand target DNA. To test this hypothesis, we used UV/Vis spectroscopy, atomic for microscopy (AFM) and dynamic light scattering (DLS). DNA analysis is demonstrated by a peak shift of the certain peak of the small molecules attached to the SERS substrate surface instead of SERS spectrum obtained in the presence of target DNA from the Raman reporter molecules. The degree of peak shifting will be used for the quantification of the target DNA in the sample. Plasmonic properties of SERS substrates and reproducibility issues will not be considerable due to the use of peak shifting instead of peak intensity for the qualitative analysis.
Coherent electron transfer in polyacetylene
Energy Technology Data Exchange (ETDEWEB)
Psiachos, D., E-mail: dpsi@physics.uoc.gr
2014-06-03
Highlights: • We study electron–ion dynamics in a donor–acceptor system. • We find two distinct electron-transfer regimes: hopping and tunnelling. • We establish conditions for achieving ballistic electron transfer. • Lattice vibrations can dramatically affect the rate of electron transfer. • Decoherence due to lattice vibrations is limited in the tunnelling regime. - Abstract: We examine, using mixed classical-quantum electron–ion dynamics, electron transfer in a donor–acceptor-like molecular junction system based on polyacetylene. We identify two qualitatively-different transfer regimes: hopping and tunnelling. We discuss the criteria for achieving each one and for minimising inelastic scattering and decoherence arising from the coupling to the ions, and we connect our main results to quantities derived from electron dynamics involving simpler, three-state model systems. We identify the requirements to have near-ballistic transfer.
International Nuclear Information System (INIS)
Recently, an efficient numerical method, which is called the collocation spectral method (CSM), for radiative heat transfer problems, has been proposed by the present authors. In this numerical method there exists the exponential convergence rate, which can obtain a very high accuracy even using a small number of grids. In this article, the CSM based on body-fitted coordinates (BFC) is extended to simulate radiative heat transfer problems in participating medium confined in 2D complex geometries. This numerical method makes simultaneously the use of the merits of both the CSM and BFC. In this numerical approach, the radiative transfer equation (RTE) in orthogonal Cartesian coordinates should be transformed into the equation in body-fitted nonorthogonal curvilinear coordinates. In order to test the efficiency of the developed method, several 2D complex irregular enclosures with curved boundaries and containing an absorbing, emitting and scattering medium are examined. The results obtained by the CSM are assessed by comparing the predictions with those in references. These comparisons indicate that the CSM based on BFC can be recommended as a good option to solve radiative heat transfer problems in complex geometries. -- Highlights: ► Collocation spectral method based on body fitted coordinates. ► RTE in irregular systems. ► The most possibility of direct solutions.
The Limits of Market-Based Risk Transfer and Implications for Managing Systemic Risks
Nicolas R. Blancher; François Haas; John Kiff; Oksana Khadarina; Paul S. Mills; Parmeshwar Ramlogan; William Lee; Yoon Sook Kim; Todd Groome; Shinobu Nakagawa
2006-01-01
The paper discusses the limits to market-based risk transfer in the financial system and the implications for the management of systemic long-term financial risks. Financial instruments or markets to transfer and better manage these risks across institutions and sectors are, as yet, either nascent or nonexistent. As such, the paper investigates why these markets remain "incomplete." It also explores a range of options by which policymakers may encourage the development of these markets as par...
SOLAR ABSORBING COOLING SYSTEMS BASED ON MULTISTAGE HEAT-MASS-TRANSFER DEVICES
Doroshenko A.V.; Ludnitsky K.V.
2014-01-01
The article presents the worked out schematics for the alternative refrigeration systems and of air-conditioning systems, based on the use of absorbing cycle and of the sunny energy for the regeneration (renewals) of absorbent solution. We use here the cascade principle of construction of all heat-mass-transfer apparatus with variation of both the temperature level and the growth of absorbent concentration on the cascade stages. The heat-mass-transfer equipment as a part of the drying and coo...
International Nuclear Information System (INIS)
The published data on the synthesis and photochemical properties of porphyrin-based molecular ensembles which represent models of natural photosynthetic light-harvesting complexes are generalised and systematised. The dependence of the transfer of excitation energy on the distance between donor and acceptor components, their mutual arrangement, electronic and environmental factors are discussed. Two mechanisms of energy transfer reactions, viz., 'through space' and 'through bond', are considered. The bibliography includes 96 references.
Risk Contagion in Chinese Banking Industry: A Transfer Entropy-Based Analysis
Jianping Li; Changzhi Liang; Xiaoqian Zhu; Xiaolei Sun; Dengsheng Wu
2013-01-01
What is the impact of a bank failure on the whole banking industry? To resolve this issue, the paper develops a transfer entropy-based method to determine the interbank exposure matrix between banks. This method constructs the interbank market structure by calculating the transfer entropy matrix using bank stock price sequences. This paper also evaluates the stability of Chinese banking system by simulating the risk contagion process. This paper contributes to the literature on interbank cont...
Effective generation of transgenic pigs and mice by linker based sperm-mediated gene transfer.
Shih Ping Yao; Ho Pei-Yu; Huang Hsiao-I; Bolen James; Brown Lucy; Hsiao Chin-Ton; Lo Hsin-Lung; Lai Chao-Kuen; Chen Chi-Dar; Wu Ming-Che; Liu Yi-Hsin; Jiang MeiSheng; Qian Jin; Chang Keejong; Yao Chen-Wen
2002-01-01
Abstract Background Transgenic animals have become valuable tools for both research and applied purposes. The current method of gene transfer, microinjection, which is widely used in transgenic mouse production, has only had limited success in producing transgenic animals of larger or higher species. Here, we report a linker based sperm-mediated gene transfer method (LB-SMGT) that greatly improves the production efficiency of large transgenic animals. Results The linker protein, a monoclonal ...
Safe and Secure Wireless Power Transfer Networks: Challenges and Opportunities in RF-Based Systems
Liu, Qingzhi; Yıldırım, Kasım Sinan; Pawełczak, Przemysław; Warnier, Martijn
2016-01-01
RF-based wireless power transfer networks (WPTNs) are deployed to transfer power to embedded devices over the air via RF waves. Up until now, a considerable amount of effort has been devoted by researchers to design WPTNs that maximize several objectives such as harvested power, energy outage and charging delay. However, inherent security and safety issues are generally overlooked and these need to be solved if WPTNs are to be become widespread. This article focuses on safety and security pro...
Image color transfer to evoke different emotions based on color combinations
He, Li; Qi, Hairong; Zaretzki, Russell
2013-01-01
In this paper, a color transfer framework to evoke different emotions for images based on color combinations is proposed. The purpose of this color transfer is to change the "look and feel" of images, i.e., evoking different emotions. Colors are confirmed as the most attractive factor in images. In addition, various studies in both art and science areas have concluded that other than single color, color combinations are necessary to evoke specific emotions. Therefore, we propose a novel frame...
International Nuclear Information System (INIS)
Direct climate radiative forcing depends on the aerosol optical depth τ, the single scattering albedo π, and the up-scatter fraction β; these quantities are functions of the refractive index of the particles, their size relative to the incident wavelength, and their shape. Sea-salt aerosols crystallize into cubic shapes or in agglomerates of cubic particles under low relative humidity conditions. The present study investigates the effects of the shape of dried sea-salt particles on the detection of light scattering from the particles. Ground-based measurements of scattering and backscattering coefficients have been performed with an integrating nephelometer instrument for a wavelength λ=0.55μm. The measurements are compared to two models: the Mie theory assuming a spherical shape for the particles and the Discrete Dipole Approximation (DDA) model for the hypothesis of cubic shape of the sea-salt aerosols. The comparison is made accurately by taking into account the actual range of the scattering angles measured by the nephelometer in both models that is from 7o to 170o for the scattering coefficient and from 90o to 170o for the backscattering coefficient. Modeled scattering and backscattering coefficients increase for nonspherical particles compared to spherical shape of particles with diameter larger than about 1μm. However, the comparison of the modeling results with the measurements gives best agreement for particles diameter less than about 1μm. The size distribution of the particles is measured with two instruments with different size bins: an electrical low-pressure impactor (ELPI) and an aerodynamic particle sizer (APS). It is found that the size of the bins of the instruments to determine the number concentration of the particles in accordance with their diameter is critical in the comparison of measurements with modeling
Persistent Scatterer Interferometry based detection of strong subsidence in Semarang, Indonesia
Cahyadi Kalia, Andre
2016-04-01
The City of Semarang (Indonesia) faces land subsidence since more than 100 years. The impact for the cities approximately 1.3 million inhabitants is severe: strong subsidence (up to several cm per year) affect the living environment, buildings and infrastructure. The main reasons for the subsidence is groundwater extraction, compaction of coastal sediments and construction load. In order to monitor the spatio-temporal variability of the subsidence phenomena the Persistent Scatterer Interferometry (PSI) is used. The presentation will show multiple PSI results and assess their characteristics with respect to PS density and coverage. The PSI analysis is based on SAR data stacks from ERS-1/-2 C-band data (1996-2000), ERS-1/-2 & Envisat-ASAR C-band data (2002-2006) and ALOS-Palsar L-band data (2006-2011). For the assessment of the PSI results thematic data (geological, hydrogeological maps) as well as orthorectified optical images (IKONOS 2005) are used. All three PSI results show an overall pattern of increasing subsidence towards the coastline where the subsurface is built up by unconsolidated coastal sediments. However, the PSI results based on C-band SAR data show a lower PS density ( 500 PS/km2 in urban areas) and PS coverage (no PSs in areas with rural land cover in the PSI results based on C-band) compared to the PSI result based on L-band SAR data. The main reason for this differences is the longer wavelength of the L-band (λ = 23.6 cm) compared to the C-band (λ = 5.6 cm) resulting in less temporal phase decorrelation through an increased penetration depth and higher capability to detect fast displacements.
DEFF Research Database (Denmark)
Mishra, Shantnu R.;
1980-01-01
An automatic facility for measuring the three-dimensional structure of the near fields of microwave radiators and scatterers is described. The amplitude and phase for different polarization components can be recorded in analog and digital form using a microprocessor-based system. The stored data......, and for the fields inside an absorber lined chamber....
Directory of Open Access Journals (Sweden)
Moreno-Pérez José A.
2005-01-01
Full Text Available In this paper we discuss the application of a met heuristic approach based on the Scatter Search to deal with robust optimization of the planning problem in the deploying of the Dense Wavelength Division Multiplexing (DWDM technology on an existing optical fiber network taking into account, in addition to the forecasted demands, the uncertainty in the survivability requirements.
Sorting apple fruit based on internal quality will enhance the industry’s competiveness and profitability and assure consumer satisfaction. In this research, visible and shortwave near-infrared (Vis-SWNIR) spectroscopy (460–1,100 nm) and spectral scattering (450–1,050 nm) were used for sorting apple...
Spin-transfer magnetization switching in ordered alloy-based nanopillar devices
International Nuclear Information System (INIS)
This paper reviews spin-transfer magnetization switching in ordered alloy-based nanopillar devices. L10-ordered FePt was used for one of the earliest demonstrations of spin-transfer switching in perpendicularly magnetized systems. The behaviour of magnetization switching deviates from the predictions based on a macro-spin model, suggesting incoherent magnetization switching in the system with a large perpendicular magnetic anisotropy. The effect of a 900 spin injector on spin-transfer switching was also examined using L10-ordered FePt. Full-Heusler alloys are in another fascinating material class for spin-transfer switching because of their high-spin polarization of conduction electrons and possible small magnetization damping. A B2-ordered Co2FeAl0.5Si0.5-based device showed a low intrinsic critical current density of 9.3 x 106 A cm-2 for spin-transfer switching as well as a relatively large current-perpendicular-to-plane giant-magnetoresistance (CPP-GMR) up to ∼9%. The specific physical properties of ordered alloys may be useful for fundamental studies and applications in spin-transfer switching.
Liu, Yang; Michielssen, Eric
2016-01-01
A butterfly-based fast direct integral equation solver for analyzing high-frequency scattering from two-dimensional objects is presented. The solver leverages a randomized butterfly scheme to compress blocks corresponding to near- and far-field interactions in the discretized forward and inverse electric field integral operators. The observed memory requirements and computational cost of the proposed solver scale as O(Nlog^2N) and O(N^1.5 logN), respectively. The solver is applied to the analysis of scattering from electrically large objects spanning over ten thousand of wavelengths and modeled in terms of five million unknowns.
International Nuclear Information System (INIS)
The 3S1-3D1 mixing parameter ε1 and the 3PJ phase shifts in the N-N system at low energy are investigated in the three nucleon system. The sensitivity of polarization transfer coefficients in p-d elastic scattering is determined by rigorous Faddeev calculations using Paris and Bonn potentials. The experimental results of Kysup(y') favours the tensor force component of the Bonn A potential. (orig.)
A 3D radiative transfer framework: III. periodic boundary conditions
Hauschildt, Peter H.; Baron, E.
2008-01-01
We present a general method to solve radiative transfer problems including scattering in the continuum as well as in lines in 3D configurations with periodic boundary conditions. he scattering problem for line transfer is solved via means of an operator splitting (OS) technique. The formal solution is based on a full characteristics method. The approximate $\\Lambda$ operator is constructed considering nearest neighbors exactly. The code is parallelized over both wavelength and solid angle usi...
Transfer Alignment for Space Vehicles Launched from a Moving Base
Directory of Open Access Journals (Sweden)
S. K. Chaudhuri
2005-07-01
Full Text Available Alignment of the inertial measurement unit (IMU is a prerequisite for any space vehicle with self-contained navigation and guidance for any mission-critical application. Normally, inertialmeasurement unit is aligned through gyro-compassing using the stored data for heading. In case of launch from a moving base, it is essential to align the inertial measurement unit in the vehicle (slave unit with that mounted on the moving platform (master unit. The master inertial navigation system is more accurate, stable, and calibrated wrt the slave unit. An error propagation system involving the misalignment between the master and the slave has been formulated involving the three misalignment angles, three velocity errors, and three positional errors. The manoeuvre of the moving base excites the sensors of both the master and the slave inertial navigation systems for the generation of data to be used in aligning the slave inertial measurement unit of the inertial navigation system (strapdown mode. The entire duration of manoeuvre has to be reduced to a minimum with minimum effort of manoeuvre. This involves the deployment of an adaptive estimator and a linear quadratic Gaussian regulator for alignment of the strapdown slave inertial navigation system.
Chip-Scale Bioassays Based on Surface-Enhanced Raman Scattering: Fundamentals and Applications
Energy Technology Data Exchange (ETDEWEB)
Hye-Young Park
2005-12-17
This work explores the development and application of chip-scale bioassays based on surface-enhanced Raman scattering (SERS) for high throughput and high sensitivity analysis of biomolecules. The size effect of gold nanoparticles on the intensity of SERS is first presented. A sandwich immunoassay was performed using Raman-labeled immunogold nanoparticles with various sizes. The SERS responses were correlated to particle densities, which were obtained by atomic force microscopy (AFM). The response of individual particles was also investigated using Raman-microscope and an array of gold islands on a silicon substrate. The location and the size of individual particles were mapped using AFM. The next study describes a low-level detection of Escherichia coli 0157:H7 and simulants of biological warfare agents in a sandwich immunoassay format using SERS labels, which have been termed Extrinsic Raman labels (ERLs). A new ERL scheme based on a mixed monolayer is also introduced. The mixed monolayer ERLs were created by covering the gold nanoparticles with a mixture of two thiolates, one thiolate for covalently binding antibody to the particle and the other thiolate for producing a strong Raman signal. An assay platform based on mixed self-assembled monolayers (SAMs) on gold is then presented. The mixed SAMs were prepared from dithiobis(succinimidyl undecanoate) (DSU) to covalently bind antibodies on gold substrate and oligo(ethylene glycol)-terminated thiol to prevent nonspecific adsorption of antibodies. After the mixed SAMs surfaces, formed from various mole fraction of DSU were incubated with antibodies, AFM was used to image individual antibodies on the surface. The final study presents a collaborative work on the single molecule adsorption of YOYO-I labeled {lambda}-DNA at compositionally patterned SAMs using total internal reflection fluorescence microscopy. The role of solution pH, {lambda}-DNA concentration, and domain size was investigated. This work also revealed
Modelling heat and mass transfer in a membrane-based air-to-air enthalpy exchanger
Dugaria, S.; Moro, L.; Del, D., Col
2015-11-01
The diffusion of total energy recovery systems could lead to a significant reduction in the energy demand for building air-conditioning. With these devices, sensible heat and humidity can be recovered in winter from the exhaust airstream, while, in summer, the incoming air stream can be cooled and dehumidified by transferring the excess heat and moisture to the exhaust air stream. Membrane based enthalpy exchangers are composed by different channels separated by semi-permeable membranes. The membrane allows moisture transfer under vapour pressure difference, or water concentration difference, between the two sides and, at the same time, it is ideally impermeable to air and other contaminants present in exhaust air. Heat transfer between the airstreams occurs through the membrane due to the temperature gradient. The aim of this work is to develop a detailed model of the coupled heat and mass transfer mechanisms through the membrane between the two airstreams. After a review of the most relevant models published in the scientific literature, the governing equations are presented and some simplifying assumptions are analysed and discussed. As a result, a steady-state, two-dimensional finite difference numerical model is setup. The developed model is able to predict temperature and humidity evolution inside the channels. Sensible and latent heat transfer rate, as well as moisture transfer rate, are determined. A sensitive analysis is conducted in order to determine the more influential parameters on the thermal and vapour transfer.
Liu, Yu; Shi, Jing; Fan, Ya; Song, Wei; Miao, Xin-hui; Zhang, Min-shan; Xu, Rong; Tan, Yong; Cai, Hong-xing
2015-03-01
The detection and recognition for the attitude of space target is a technical problem and research focus. In this paper the attitude inversion technique of space target was explored based scattering spectroscopy. The scattering spectra of the space shuttle model instead of space target in the laboratory were detected in 0～360° direction at 10° intervals, and the spectral database of the one-dimensional rotating space shuttle model was established. Based on spectral bidirectional reflectance distribution function (SBRDF) theoretical model, the experimental data were compared with the data in the database using residual as a reference. When the rotation angle of the space shuttle model was 8°, 68°, 293°, the angle corresponding to the minimum residual was 10°, 70°, 290°. The results indicated that the inversion of rotation angle of the space shuttle model was achieved and inversion accuracy is better than 5°. According to the redundancy of spectral data (700 effective bands), if the angle interval of spectral data was reduced, the attitude inversion of space target of higher angle accuracy can be achieved. In this paper, for the first time the one-dimensional attitude inversion of the space shuttle model was realized based on the scattering spectrum, and the correlation between scattering spectra and attitude was confirmed. This research is helpful to the application of spectroscopy in the field of the attitude inversion of space target.
Granger, Jennifer H; Granger, Michael C; Firpo, Matthew A; Mulvihill, Sean J; Porter, Marc D
2013-01-21
Proteomic analyses of readily obtained human fluids (e.g., serum, urine, and saliva) indicate that the diagnosis of complex diseases will be enhanced by the simultaneous measurement of multiple biomarkers from such samples. This paper describes the development of a nanoparticle-based multiplexed platform that has the potential for simultaneous read-out of large numbers of biomolecules. For this purpose, we have chosen pancreatic adenocarcinoma (PA) as a test bed for diagnosis and prognosis. PA is a devastating form of cancer in which an estimated 86% of diagnoses resulted in death in the United States in 2010. The high mortality rate is due, in part, to the asymptomatic development of the disease and the dearth of sensitive diagnostics available for early detection. One promising route lies in the development of a serum biomarker panel that can generate a signature unique to early stage PA. We describe the design and development of a proof-of-concept PA biomarker immunoassay array coupled with surface-enhanced Raman scattering (SERS) as a sensitive readout method. PMID:23150876
Kaszowska, Zofia; Malek, Kamilla; Staniszewska-Slezak, Emilia; Niedzielska, Karina
2016-12-01
This work presents an in-depth study on Raman spectra excited with 1064 and 532nm lasers of lime binders employed in the past as building materials and revealed today as valuable conservation materials. We focus our interest on the bands of strong intensity, which are present in the spectra of all binders acquired with laser excitation at 1064nm, but absent in the corresponding spectra acquired with laser excitation at 532nm. We suggest, that the first group of spectra represents fluorescence phenomena of unknown origin and the second true Raman scattering. In our studies, we also include two other phases of lime cycle, i.e. calcium carbonate (a few samples of calcite of various origins) and calcium oxide (quicklime) to assess how structural and chemical transformations of lime phases affect the NIR-Raman spectral profile. Furthermore, we analyse a set of carbonated limewashes and lime binders derived from old plasters to give an insight into their spectral characteristics after excitation with the 1064nm laser line. NIR-Raman micro-mapping results are also presented to reveal the spatial distribution of building materials and fluorescent species in the cross-section of plaster samples taken from a 15th century chapel. Our study shows that the Raman analysis can help identify lime-based building and conservation materials, however, a caution is advised in the interpretation of the spectra acquired using 1064nm excitation. PMID:27314909
Tunable Stokes laser generation based on the stimulated polariton scattering in KTiOPO₄ crystal.
Jiang, Shiqi; Chen, Xiaohan; Cong, Zhenhua; Zhang, Xingyu; Qin, Zengguang; Liu, Zhaojun; Wang, Weitao; Li, Ning; Fu, Qiang; Lu, Qingming; Zhang, Shaojun
2015-07-27
The tunable Stokes laser characteristics based on the stimulated polariton scattering in KTiOPO4 (KTP) crystal and the intracavity frequency doubling properties for the Stokes laser are investigated for the first time. When the pumping laser wavelength is 1064.2 nm, and the angle between the pumping and Stokes beams outside the KTP crystal changes from 1.875° to 6.750°, the obtained tunable Stokes laser wavelength varies discontinuously from 1076.5 nm to 1091.4 nm with four gaps. When the pumping pulse energy is 120.0 mJ, the maximum Stokes pulse energy is 46.5 mJ obtained at the wavelength of 1086.6 nm. By inserting a LiB3O5 (LBO) crystal into the cavity, the obtained frequency-doubled laser wavelength is inconsecutive tunable from 538.5 nm to 543.8 nm. The maximum frequency-doubled laser pulse energy is 15.9 mJ at the wavelength of 543.5 nm. PMID:26367675
All-optical pulse compression of broadband microwave signal based on stimulated Brillouin scattering
Long, Xin; Chen, Jianping
2015-01-01
Pulse compression processing based on stimulated Brillouin scattering (SBS) in an optical fiber is theoretically and experimentally demonstrated. Broadband microwave signal is electro-optically modulated onto the pump lightwave that is launched into one end of the fiber. Acoustic wave in the fiber inherits the amplitude and phase information of the pump lightwave and thus the coupling between the acoustic wave and pump lightwave leads to the auto-correlated process of the pump lightwave as well as the modulated microwave signal. Derivation of the SBS coupling equations shows that the short-pulse probe lightwave amplified by the pump lightwave possesses the nature of auto-correlation formula. All-optical pulse compression of the broadband microwave signal is implemented after a subtraction between the detected probe pulse with and without SBS. A proof-of-concept experiment is carried out. The pulse compression of a linear frequency-modulated microwave signal with 1 GHz sweep range at the carrier frequency of 4...
Byrnes, Adam; Pant, Ravi; Li, Enbang; Choi, Duk-Yong; Poulton, Christopher G; Fan, Shanhui; Madden, Steve; Luther-Davies, Barry; Eggleton, Benjamin J
2012-08-13
We report the first demonstration of a photonic chip based dynamically reconfigurable, widely tunable, narrow pass-band, high Q microwave photonic filter (MPF). We exploit stimulated Brillouin scattering (SBS) in a 6.5 cm long chalcogenide (As2S3) photonic chip to demonstrate a MPF that exhibited a high quality factor of ~520 and narrow bandwidth and was dynamically reconfigurable and widely tunable. It maintained a stable 3 dB bandwidth of 23 ± 2MHz and amplitude of 20 ± 2 dB over a large frequency tuning range of 2-12 GHz. By tailoring the pump spectrum, we reconfigured the 3 dB bandwidth of the MPF from ~20 MHz to ~40 MHz and tuned the shape factor from 3.5 to 2 resulting in a nearly flat-topped filter profile. This demonstration represents a significant advance in integrated microwave photonics with potential applications in on-chip microwave signal processing for RADAR and analogue communications. PMID:23038523
The Scatter Search Based Algorithm to Revenue Management Problem in Broadcasting Companies
Pishdad, Arezoo; Sharifyazdi, Mehdi; Karimpour, Reza
2009-09-01
The problem under question in this paper which is faced by broadcasting companies is how to benefit from a limited advertising space. This problem is due to the stochastic behavior of customers (advertiser) in different fare classes. To address this issue we propose a mathematical constrained nonlinear multi period model which incorporates cancellation and overbooking. The objective function is to maximize the total expected revenue and our numerical method performs it by determining the sales limits for each class of customer to present the revenue management control policy. Scheduling the advertising spots in breaks is another area of concern and we consider it as a constraint in our model. In this paper an algorithm based on Scatter search is developed to acquire a good feasible solution. This method uses simulation over customer arrival and in a continuous finite time horizon [0, T]. Several sensitivity analyses are conducted in computational result for depicting the effectiveness of proposed method. It also provides insight into better results of considering revenue management (control policy) compared to "no sales limit" policy in which sooner demand will served first.
Remote Sensing of Soil Moisture based on Dynamic Vegetation Scattering Properties for AMSR sensors
Du, J.; Kimball, J. S.; Jones, L. A.
2015-12-01
Accurate mapping of soil moisture and its spatial-temporal variations are of great significance to scientific studies on global water, energy and carbon cycles as well as operational applications including flood and drought monitoring, water resources management and crop yield forecasts. An approach for deriving volumetric soil moisture using satellite passive microwave radiometry from the Advanced Microwave Scanning Radiometers AMSR-E and AMSR2 was developed in this study. The algorithm adopts a weighted averaging strategy for soil moisture estimation based on a dynamic selection of empirically determined vegetation single-scatter albedo values. The resulting soil moisture retrievals demonstrate more realistic global patterns and seasonal dynamics relative to the baseline University of Montana (UMT) soil moisture product. Quantitative analysis of the new approach against in situ soil moisture measurements over four global study regions also indicates significant improvement over the baseline algorithm, with coefficients of determination (R2) between the retrievals and in-situ measurements increasing by approximately 16.9% and 41.5% respectively; and bias-corrected RMSEs decreasing by about 25.0% and 38.2% for respective ascending and descending orbital data records. Initial comparisons between soil moisture retrievals from AMSR2 and SMAP indicate coherent global and seasonal patterns.
Chen, Kun; Han, Heyou; Luo, Zhihui
2012-03-01
An immunoassay based on surface enhanced Raman scattering (SERS) spectroscopy was developed to detect muramidase released protein (MRP) antibody against Streptococcus suis II (SS2) utilizing thorny gold nanoparticles (tAuNPs) as SERS substrates. Initially, tAuNPs with multi-branches were prepared by the seed-mediated growth method in the absence of templates and surfactants, facilitating p-mercaptobenzoic acid (pMBA) conjugation covalently onto the tAuNPs through S-Au bonds. The obtained immuno-SERS tag affording strong Raman signals made it possible to establish an application of indirect detection of the MRP antibody against SS2 with a sandwich assay at a highly sensitive level. The Raman intensity at 1588 cm(-1) was proportional to the logarithm of the concentration of MRP antibody in the range of 10 pg mL(-1) to 0.1 μg mL(-1). The detection sensitivity was significantly improved to 0.1 pg mL(-1) by using the immuno-SERS tags. Furthermore, the proposed SERS approach was applied to detect MRP antibody in pig serum samples, and the results agreed well with those of ELISA, indicating great potential for clinical application in diagnostic immunoassays. PMID:22282767
High efficiency x-ray source based on inverse Compton scattering in an optical Bragg structure
International Nuclear Information System (INIS)
Existing x-ray sources based on inverse Compton scattering rely on free-space lasers and have modest efficiency due to the inherent limitation of maintaining their peak field intensity over a few Rayleigh lengths. Moreover, their typical interaction spots are tens of micrometres in diameter and they rely on large electron accelerators. We propose a new structure that mitigates many of these limiting factors by confining the interaction in an optical Bragg waveguide, specially designed to support a TEM mode within its sub-micrometre hollow core. This allows the e-beam-laser interaction to be as long as the waveguide itself, resulting in superior spectral quality of the emerging x-ray. Furthermore, the regular RF accelerator may be replaced by an optical Bragg accelerator. This two-stage design, from acceleration to x-ray emission, is expected to have a table-top size, and it is estimated to provide x-ray brightness of 3 x 1017 (photons s-1 mm-2 mrad-2/0.1%BW), while utilizing laser power several orders of magnitude smaller than comparable free-space sources.
Chen, Guodong; Zhang, Ruiwen; Sun, Junqiang; Xie, Heng; Gao, Ya; Feng, Danqi; Xiong, Huang
2014-12-29
We propose a scheme for on-chip all optical mode conversion based on forward stimulated Brillouin scattering in a hybrid phononic-photonic waveguide. To describe the mode conversion the theoretical model of the FSBS is established by taking into account the radiation pressure and the electrostriction force simultaneously. The numerical simulation is carried out for the mode conversion from the fundamental mode E11x to the higher-order mode E21x. The results indicate that the mode conversion efficiency is affected by the waveguide length and the input pump light power, and the highest efficiency can reach upto 88% by considering the influence of optical and acoustic absorption losses in the hybrid waveguide. Additionally, the conversion bandwidth with approximate 12.5 THz can be achieved in 1550nm communication band. This mode converter on-chip is a promising device in the integrated optical systems, which can effectively increase the capacity of silicon data busses for on-chip optical interconnections. PMID:25607172
Direct diagnostic technique of high-intensity laser profile based on laser-compton scattering
International Nuclear Information System (INIS)
A high-intensity laser is essential for plasma generation for EUV (Extreme Ultraviolet) lithography, which is studied as the next generation of ultra-fine semiconductor lithography. Nevertheless, there is no way to directly measure profile of high-intensity laser at the present day. Therefore, we have been developing a method for measuring high-intensity laser profile based on the laser-Compton scattering using Cs-Te photo cathode RF-Gun at Waseda University. Specifically, laser profile is obtained by scanning the electron beam which is focused to about 10μm by solenoid lens. We have simulated beam size focused by solenoid lens using tracking code GPT (General Particle Tracer) and optimized the beam parameter to obtain beam size of 10μm. Then, we have installed solenoid lens and generated focused beam. We measured beam size using radiochromic film called GAFCHROMIC dosimetry film type HD-810. In this conference, we will report the result of GPT simulations, beam size measurements, the present progress and future prospects. (author)
Liu, Yan; Ma, Cheng; Shen, Yuecheng; Wang, Lihong V.
2016-03-01
Optical focusing plays a central role in biomedical optical imaging, manipulation, and therapy. However, in scattering media, direct optical focusing becomes infeasible beyond ~10 mean free paths. To break this limit, time-reversed ultrasonically encoded (TRUE) optical focusing phase-conjugates ultrasonically tagged diffuse light back to the ultrasonic focus, thus forming a focus deep inside scattering media. In previous works, the speed of wavefront measurement was limited by the low frame rate of the camera used to record the four images required for phase-shifting holography. Moreover, most of the bits of a pixel value were used to represent an informationless background caused by the large amount of untagged light, increasing the amount of data to transfer and necessitating the use of costly high-resolution analog-to-digital converters (ADCs). Here, we developed a digital TRUE focusing system based on a lock-in camera (300×300 pixels), in which each pixel performs analog lock-in detection on chip. Since only the information of the signal, not that of the background, is digitized, the lock-in camera reduces the amount of data to transfer, and enables the use of cheap low-resolution ADCs. Using this lock-in camera, we were able to measure the wavefront of ultrasonically tagged light in less than 0.3 ms, and to achieve TRUE focusing in between two ground glass diffusers. Even when the signal-to-background ratio dropped to 6.32×10^-4, a phase sensitivity as low as 0.51 rad could still be realized, which is more than enough for digital optical phase conjugation.
Comparison of Ion Transfer Thermodynamics at Microfluidic and Droplet-Based Three Phase Electrodes
International Nuclear Information System (INIS)
Highlights: • Ion transfer processes at microfluidic three phase electrodes were studied. • The voltammetric peak potentials depend on ion hydrophobicity and concentration. • The model developed for droplet based systems can be used also in microfluidics. • The volumetric flow rate does not affect the recorded peak potentials. • Gibbs energies of ion transfer from water to N-octyl-2-pyrrolidone were determined. - Abstract: We have investigated whether the thermodynamic model developed for ion transfer processes across the liquid|liquid interface at a droplet-based three phase electrode (TPE) can be applied to a microfluidic system. We have compared effect of ion transfer potential and ion concentration on the voltammetric peak potential recorded at droplet and microfluidic TPEs. The results were analyzed in terms of the Nernst-like equation derived for droplet TPE. As a model reaction, electrooxidation of decamethylferrocene coupled to anion transfer from aqueous electrolyte solution to N-octyl-2-pyrrolidone (NOP) has been chosen. We have found that both ion effect and concentration effect are the same in the two systems and agree with the Nernst equation. This allows microfluidic TPEs to be used in electroanalysis. Additionally, Gibbs energies of transfer for different inorganic anions have been determined for the studied NOP water biphasic system
The effect of dyad versus individual simulation-based ultrasound training on skills transfer
DEFF Research Database (Denmark)
Tolsgaard, Martin G; Madsen, Mette E; Oxlund, Birgitte S;
2015-01-01
completed the transfer test. Dyad training was found to be non-inferior to single-student training: transfer test OSAUS scores were significantly higher than the pre-specified non-inferiority margin (delta score 7.8%, 95% confidence interval -3.8-19.6%; p = 0.04). More dyad (71.4%) than single (30......CONTEXT: Dyad practice may be as effective as individual practice during clinical skills training, improve students' confidence, and reduce costs of training. However, there is little evidence that dyad training is non-inferior to single-student practice in terms of skills transfer. OBJECTIVES......: This study was conducted to compare the effectiveness of simulation-based ultrasound training in pairs (dyad practice) with that of training alone (single-student practice) on skills transfer. METHODS: In a non-inferiority trial, 30 ultrasound novices were randomised to dyad (n = 16) or single...
A Model-Based Scatter Artifacts Correction for Cone Beam CT
Zhao, Wei; Zhu, Jun; Wang, Luyao; Xing, Lei
2016-01-01
The purpose of this work is to provide a fast and accurate scatter artifacts correction algorithm for cone beam CT (CBCT) imaging. The method starts with an estimation of coarse scatter profiles for a set of CBCT data in either image domain or projection domain. A denoising algorithm designed specifically for Poisson signals is then applied to derive the final scatter distribution. Qualitative and quantitative evaluations using thorax and abdomen phantoms with Monte Carlo (MC) simulations, experimental Catphan phantom data, and in vivo human data acquired for a clinical image guided radiation therapy were performed. Results show that the proposed algorithm can significantly reduce scatter artifacts and recover the correct HU in either projection domain or image domain. For the MC thorax phantom study, four components segmentation yield the best results, while the results of three components segmentation are still acceptable. For the Catphan phantom data, the mean value over all pixels in the residual image is...
Theoretical study of the influence of ribose on the proton transfer phenomenon of nucleic acid bases
International Nuclear Information System (INIS)
The first comprehensive theoretical study of ribose's effects on the behavior of proton transfer of nucleic acid base is presented. The specific hydrogen bonding of the ribose hydroxyls plays a very important role in the stabilization of the structure of ribonucleoside. Nine stable uridine conformations have been reported. The intermolecular proton transfer of the isolated, monohydrated uridine complexes in three different regions were extensively explored on the basis of density functional theory at the B3LYP/6-31+G* level. With the introduction of the ribose, not only the structural parameters of the nucleic acid bases changed, but also the energy barriers of the proton transfer process changed. Furthermore, changes of the electron distributions of the molecular orbital of the nucleic acid bases were also analyzed by NBO analysis. Consideration of the ribose's influence represents a much more real situation in the RNA
Preparation and Phase Transfer of Hydrophobic CdSe-Based Quantum Dots.
Du, Yingying; Yang, Ping; Zhu, Yuanna; Zhang, Qiang
2015-03-01
Monodispersed CdTe(x)Se1-x and CdSe cores were synthesized via organic methods. The as-prepared cores were coated with a Cd(y)Zn1-yS shell by an epitaxial growth. Compared with the cores, an obvious red shift was observed in both the absorption and photoluminescence (PL) spectra of core-shell quantum dots (QDs) and the PL efficiency was improved. The CdSe-based core-shell QDs were transferred from oil to water phase by the encapsulation of amphiphilic polymers. The ligands of QDs, namely hexadecylamine (HDA) and oleic acid (OA), dramatically influenced the process of phase transfer. The process of phase transfer of HDA-coated CdTe(x)Se1-x/CdyZn1-yS core-shell QDs was failed, however, the OA-coated CdSe/CdyZn1-yS core-shell QDs can be successfully transferred from oil to water phase. This is ascribed that the surface ligand HDA falls from CdTe(x)Se1-x/Cd(y)Zn1-yS core-shell QDs during the process of phase transfer, leading to non-interaction between QDs and amphiphilic polymers. The effect of molecular weight of the poly(styrene-co-maleic anhydride) (PSMA) on the phase transfer was also investigated. For the QDs with the same size, the PSMA with high molecular weight exhibit a shorter time in the process of phase transfer compared with light molecular weight. Furthermore, the size of the QDs also affects the process of the phase transfer from oil to water phase. The smaller of the QDs, the shorter of the phase transfer time. PMID:26413657
Carbon nanohorn-based nanofluids: characterization of the spectral scattering albedo
Mercatelli, Luca; Sani, Elisa; Giannini, Annalisa; Di Ninni, Paola; Martelli, Fabrizio; Zaccanti, Giovanni
2012-01-01
The full characterization of the optical properties of nanofluids consisting of single-wall carbon nanohorns of different morphologies in aqueous suspensions is carried out using a novel spectrophotometric technique. Information on the nanofluid scattering and absorption spectral characteristics is obtained by analyzing the data within the single scattering theory and validating the method by comparison with previous monochromatic measurements performed with a different technique. The high ab...
On the HSAB based estimate of charge transfer between adsorbates and metal surfaces
International Nuclear Information System (INIS)
Graphical abstract: Left: molecule-to-metal electron charge transfer (ΔN) is proportional to the difference between the metal’s work function and molecular electronegativity. Right: correlation between the work function and explicitly DFT calculated ΔN. Highlights: ► HSAB based electron transfer parameter, ΔN, is analyzed for adsorbates on metal surfaces. ► ΔN gives reasonably estimated trends of charge transfer for atomic and molecular adsorbates. ► Adatom-metal bond strength is linearly proportional to metal-to-adatom charge transfer. ► DFT calculated adsorption energies of the N, O, and Cl adatoms on 11 different metals. ► DFT calculated work functions of low Miller index surfaces for 11 different metals. - Abstract: The applicability of the HSAB based electron charge transfer parameter, ΔN, is analyzed for molecular and atomic adsorbates on metal surfaces by means of explicit DFT calculations. For molecular adsorbates ΔN gives reasonable trends of charge transfer if work function is used for electronegativity of metal surface. For this reason, calculated work functions of low Miller index surfaces for 11 different metals are reported. As for reactive atomic adsorbates, e.g., N, O, and Cl, the charge transfer is proportional to the adatom valence times the electronegativity difference between the metal surface and the adatom, where the electronegativity of metal is represented by a linear combination of atomic Mulliken electronegativity and the work function of metal surface. It is further shown that the adatom-metal bond strength is linearly proportional to the metal-to-adatom charge transfer thus making the ΔN parameter a useful indicator to anticipate the corresponding adsorption energy trends.
Physics picture from neutron scattering study on Fe-based superconductors
Institute of Scientific and Technical Information of China (English)
Bao Wei
2013-01-01
Neutron scattering,with its ability to measure the crystal structure,the magnetic order,and the structural and magnetic excitations,plays an active role in investigating various families of Fe-based high-Tc superconductors.Three different types of antiferromagnetic orders have been discovered in the Fe plane,but two of them cannot be explained by the spin-densitywave (SDW) mechanism of nesting Fermi surfaces.Noticing the close relation between antiferromagnetic order and lattice distortion in orbital ordering from previous studies on manganites and other oxides,we have advocated orbital ordering as the underlying common mechanism for the structural and antiferromagnetic transitions in the 1111,122,and 11 parent compounds.We observe the coexistence of antiferromagnetic order and superconductivity in the (Ba,K)Fe2As2 system,when its phase separation is generally accepted.Optimal Tc is proposed to be controlled by the local FeAs4 tetrahedron from our investigation on the 1111 materials.The Bloch phase coherence of the Fermi liquid is found crucial to the occurrence of bulk superconductivity in iron chalcogenides of both the 11 and the 245 families.Iron chalcogenides carry a larger staggered magnetic moment (＞ 2 μB/Fe) than that in iron pnictides (＜ 1 μB/Fe) in the antiferromagnetic order.Normal state magnetic excitations in the 11 superconductor are of the itinerant nature while in the 245 superconductor the spin-waves of localized moments.The observation of superconducting resonance peak provides a crucial piece of information in current deliberation of the pairing symmetry in Fe-based superconductors.
Composed Scattering Model for Direct Volume Rendering
Institute of Scientific and Technical Information of China (English)
蔡文立; 石教英
1996-01-01
Based on the equation of transfer in transport theory of optical physics,a new volume rendering model,called composed scattering model(CSM),is presented.In calculating the scattering term of the equation,it is decomposed into volume scattering intensity and surface scattering intensity,and they are composed with the boundary detection operator as the weight function.This proposed model differs from the most current volume rendering models in the aspect that in CSM segmentation and illumination intensity calculation are taken as two coherent parts while in existing models they are regarded as two separate ones.This model has been applied to the direct volume rendering of 3D data sets obtained by CT and MRI.The resultant images show not only rich details but also clear boundary surfaces.CSM is demonstrated to be an accurate volume rendering model suitable for CT and MRI data sets.
Design of Wideband MIMO Car-to-Car Channel Models Based on the Geometrical Street Scattering Model
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Nurilla Avazov
2012-01-01
Full Text Available We propose a wideband multiple-input multiple-output (MIMO car-to-car (C2C channel model based on the geometrical street scattering model. Starting from the geometrical model, a MIMO reference channel model is derived under the assumption of single-bounce scattering in line-of-sight (LOS and non-LOS (NLOS propagation environments. The proposed channel model assumes an infinite number of scatterers, which are uniformly distributed in two rectangular areas located on both sides of the street. Analytical solutions are presented for the space-time-frequency cross-correlation function (STF-CCF, the two-dimensional (2D space CCF, the time-frequency CCF (TF-CCF, the temporal autocorrelation function (ACF, and the frequency correlation function (FCF. An efficient sum-of-cisoids (SOCs channel simulator is derived from the reference model. It is shown that the temporal ACF and the FCF of the SOC channel simulator fit very well to the corresponding correlation functions of the reference model. To validate the proposed channel model, the mean Doppler shift and the Doppler spread of the reference model have been matched to real-world measurement data. The comparison results demonstrate an excellent agreement between theory and measurements, which confirms the validity of the derived reference model. The proposed geometry-based channel simulator allows us to study the effect of nearby street scatterers on the performance of C2C communication systems.
Energy Technology Data Exchange (ETDEWEB)
Shang Li; Dong Shaojun [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun 130022 (China)], E-mail: dongsj@ciac.jl.cn
2008-03-05
A simple light scattering detection method for neurotransmitters has been developed, based on the growth of gold nanoparticles. Neurotransmitters (dopamine, L-dopa, noradrenaline and adrenaline) can effectively function as active reducing agents for generating gold nanoparticles, which result in enhanced light scattering signals. The strong light scattering of gold nanoparticles then allows the quantitative detection of the neurotransmitters simply by using a common spectrofluorometer. In particular, Au-nanoparticle seeds were added to facilitate the growth of nanoparticles, which was found to enhance the sensing performance greatly. Using this light scattering technique based on the seed-mediated growth of gold nanoparticles, detection limits of 4.4 x 10{sup -7} M, 3.5 x 10{sup -7} M, 4.1 x 10{sup -7} M, and 7.7 x 10{sup -7} M were achieved for dopamine, L-dopa, noradrenaline and adrenaline, respectively. The present strategy can be extended to detect other biologically important molecules in a very fast, simple and sensitive way, and may have potential applications in a wide range of fields.
Shang, Li; Dong, Shaojun
2008-03-01
A simple light scattering detection method for neurotransmitters has been developed, based on the growth of gold nanoparticles. Neurotransmitters (dopamine, L-dopa, noradrenaline and adrenaline) can effectively function as active reducing agents for generating gold nanoparticles, which result in enhanced light scattering signals. The strong light scattering of gold nanoparticles then allows the quantitative detection of the neurotransmitters simply by using a common spectrofluorometer. In particular, Au-nanoparticle seeds were added to facilitate the growth of nanoparticles, which was found to enhance the sensing performance greatly. Using this light scattering technique based on the seed-mediated growth of gold nanoparticles, detection limits of 4.4 × 10-7 M, 3.5 × 10-7 M, 4.1 × 10-7 M, and 7.7 × 10-7 M were achieved for dopamine, L-dopa, noradrenaline and adrenaline, respectively. The present strategy can be extended to detect other biologically important molecules in a very fast, simple and sensitive way, and may have potential applications in a wide range of fields.
International Nuclear Information System (INIS)
A simple light scattering detection method for neurotransmitters has been developed, based on the growth of gold nanoparticles. Neurotransmitters (dopamine, L-dopa, noradrenaline and adrenaline) can effectively function as active reducing agents for generating gold nanoparticles, which result in enhanced light scattering signals. The strong light scattering of gold nanoparticles then allows the quantitative detection of the neurotransmitters simply by using a common spectrofluorometer. In particular, Au-nanoparticle seeds were added to facilitate the growth of nanoparticles, which was found to enhance the sensing performance greatly. Using this light scattering technique based on the seed-mediated growth of gold nanoparticles, detection limits of 4.4 x 10-7 M, 3.5 x 10-7 M, 4.1 x 10-7 M, and 7.7 x 10-7 M were achieved for dopamine, L-dopa, noradrenaline and adrenaline, respectively. The present strategy can be extended to detect other biologically important molecules in a very fast, simple and sensitive way, and may have potential applications in a wide range of fields
Zhang, Yan-jun; Liu, Wen-zhe; Fu, Xing-hu; Bi, Wei-hong
2015-07-01
Traditional BOTDR optical fiber sensing system uses single channel sensing fiber to measure the information features. Uncontrolled factors such as cross-sensitivity can lead to a lower scattering spectrum fitting precision and make the information analysis deflection get worse. Therefore, a BOTDR system for detecting the multichannel sensor information at the same time is proposed. Also it provides a scattering spectrum analysis method for multichannel Brillouin optical time-domain reflection (BOT-DR) sensing system in order to extract high precision spectrum feature. This method combines the three times data fusion (TTDF) and the cuckoo Newton search (CNS) algorithm. First, according to the rule of Dixon and Grubbs criteria, the method uses the ability of TTDF algorithm in data fusion to eliminate the influence of abnormal value and reduce the error signal. Second, it uses the Cuckoo Newton search algorithm to improve the spectrum fitting and enhance the accuracy of Brillouin scattering spectrum information analysis. We can obtain the global optimal solution by smart cuckoo search. By using the optimal solution as the initial value of Newton algorithm for local optimization, it can ensure the spectrum fitting precision. The information extraction at different linewidths is analyzed in temperature information scattering spectrum under the condition of linear weight ratio of 1:9. The variances of the multichannel data fusion is about 0.0030, the center frequency of scattering spectrum is 11.213 GHz and the temperature error is less than 0.15 K. Theoretical analysis and simulation results show that the algorithm can be used in multichannel distributed optical fiber sensing system based on Brillouin optical time domain reflection. It can improve the accuracy of multichannel sensing signals and the precision of Brillouin scattering spectrum analysis effectively. PMID:26717729
Transfer of newborns to neonatal care unit: a registry based study in Northern Tanzania
Directory of Open Access Journals (Sweden)
Kibiki Gibson S
2011-10-01
for babies of non-educated fathers and a high transfer rate for first born babies, there were no signs that transfer was based on non-medical indications.
Zhou, Ying-lin; Li, Yuan-zong
2004-01-01
For the first time, poly(ethylenimine) (PEI) was used to determine nucleic acids with a light scattering technique using a common spectrofluorometer. The interaction of PEI with DNA results in greatly enhanced intensity of light scattering at 300 nm, which is caused by the formation of the big particles between DNA and PEI. Based on this, a new quantitative method for nucleic acid determination in aqueous solutions has been developed. Under the optimum conditions, the enhanced intensity of light scattering is proportional to the concentration of nucleic acid in the range of 0.01-10.0 μg ml -1 for herring sperm DNA (hsDNA), 0.02-10.0 μg ml -1 for calf thymus DNA (ctDNA), 0.02-20.0 μg ml -1 for yeast RNA (yRNA). The detection limits are 5.3, 9.9, and 13.7 ng ml -1, respectively. Synthetic samples were determined satisfactorily. At the same time, the light scattering technique has been successfully used to obtain the information on the effects of pH and ionic strength on the formation and the stability of the DNA/PEI complex, which is important in some fields such as genetic engineering and gene transfer. Using ethidium bromide (EB) as a fluorescent probe, the binding of PEI with hsDNA was studied. Both the binding constant of EB with DNA and the number of binding sites per nucleotide decrease with increasing concentration of PEI, indicating noncompetitive inhibition of EB binding to DNA in the presence of PEI. And the association constant of PEI to DNA obtained is 1.2×10 5 M -1. IR-spectra show that PEI interacts with DNA through both the phosphate groups and the bases of DNA and the formation of DNA/PEI complex may cause the change of the conformation of the DNA secondary structure, which is also proved by UV-spectra.
10BF3 Gas and 10B coating based position sensitive detectors for neutron scattering applications
International Nuclear Information System (INIS)
Global scarcity of 3He has made it essential to explore other materials with reasonably high neutron absorption cross section for thermal neutron detectors. There is also a high demand to improve the performance of neutron detectors in view of throughput. 10BF3 gas and 10B coatings in gas filled proportional detector are the favorable and promising options. Performance of BF3 gas and 10B film (90% enriched) based Position Sensitive Detectors (PSDs) in coaxial geometry are evaluated for compatibility with scattering experiments. Though efficiency of these PSDs in equivalent dimensions is lower than that those with 3He, novel designs of cathode structure are being tried to improve efficiency. Challenges in handling BF3 gas due to its toxicity and limitations in fill pressure due to its electronegative nature, limits its popularity. Whereas our in-house facility for BF3 gas generation and distillation enabled us to carry out extensive tests related to geometry parameters of the PSDs, purification of gas through repeated distillations has been helpful to a certain extent. Design parameters such as anode, cathode and fill gas pressure for BF3 filled cylindrical PSDs are optimised for their performance. Time of Flight (TOF) spectrometer is presently being installed at Dhruva reactor. For this purpose, BF3-filled multi-PSD array is under fabrication in-house. Vertically arranged 1 m long cylindrical PSDs will cover the detection area of 3.5 m2 (3.5 m arc-length and 1 m height). BF3 gas based large area PSDs need complex anode-cathode geometry for gain in efficiency. Various challenges in choice of detector fabrication materials are faced. BF3 gas aging with these fabrication materials is studied and results are implemented in the design of multi-tube based PSD. PSDs based on 10B film in coaxial geometry are successfully fabricated and tested with acceptable position resolution. 10B coatings show advantage of non toxic nature but pose challenges like low efficiency, limits
Prediction of Radionuclide transfer based on soil parameters: application to vulnerability studies
International Nuclear Information System (INIS)
The multi factorial character of the radiocaesium and radiostrontium soil-to-plan transfer, which depends on the radionuclide level in the soil solution amplified by a plant factor, prevents from establishing univariate relationships between transfer factors and soil and/or plant parameters. The plant factor is inversely proportional to the level of competitive species in the soil solution (Ca and Mg, for radiostrontium, and K and NH4 for radiocaesium). Radionuclide level in soil solution depends on the radionuclide available fraction and its distribution coefficient. For radiostrontium, this may be obtained from the Cationic Exchange Capacity (CEC), whereas for radiocaesium the Specific Interception Potential should be calculate, both corrected by the concentrations of the competitive species and selectivity coefficients. Therefore, the transfer factor eventually depends on soil solution composition, the available fraction and the number of sorption sites, as well as on the plant factor. For a given plant, a relative sequence of transfer can be set up based solely on soil parameters, since the plant factor is cancelled. This prediction model has been compared with transfer data from experiments with Mediterranean, mineral soils, contaminated with a thermo generated aerosol, and with podzolic and organic soils, contaminated by the Chernobyl fallout. These studies revealed that it was possible to predict a relative scale of transfer for any type of soil, also allowing a scale of soil vulnerability to radiostrontium and radiocaesium contamination to be set up. (Author)
Silica-gold bilayer-based transfer of focused ion beam-fabricated nanostructures.
Wu, Xiaofei; Geisler, Peter; Krauss, Enno; Kullock, René; Hecht, Bert
2015-10-21
The demand for using nanostructures fabricated by focused ion beam (FIB) on delicate substrates or as building blocks for complex devices motivates the development of protocols that allow FIB-fabricated nanostructures to be transferred from the original substrate to the desired target. However, transfer of FIB-fabricated nanostructures is severely hindered by FIB-induced welding of structure and substrate. Here we present two (ex and in situ) transfer methods for FIB-fabricated nanostructures based on a silica-gold bilayer evaporated onto a bulk substrate. Utilizing the poor adhesion between silica and gold, the nanostructures can be mechanically separated from the bulk substrate. For the ex situ transfer, a spin-coated poly(methyl methacrylate) film is used to carry the nanostructures so that the bilayer can be etched away after being peeled off. For the in situ transfer, using a micro-manipulator inside the FIB machine, a cut-out piece of silica on which a nanostructure has been fabricated is peeled off from the bulk substrate and thus carries the nanostructure to a target substrate. We demonstrate the performance of both methods by transferring plasmonic nano-antennas fabricated from single-crystalline gold flakes by FIB milling to a silicon wafer and to a scanning probe tip. PMID:26395208
Lyapunov-based Low-thrust Optimal Orbit Transfer: An approach in Cartesian coordinates
Zhang, Hantian; Cao, Qingjie
2014-01-01
This paper presents a simple approach to low-thrust optimal-fuel and optimal-time transfer problems between two elliptic orbits using the Cartesian coordinates system. In this case, an orbit is described by its specific angular momentum and Laplace vectors with a free injection point. Trajectory optimization with the pseudospectral method and nonlinear programming are supported by the initial guess generated from the Chang-Chichka-Marsden Lyapunov-based transfer controller. This approach successfully solves several low-thrust optimal problems. Numerical results show that the Lyapunov-based initial guess overcomes the difficulty in optimization caused by the strong oscillation of variables in the Cartesian coordinates system. Furthermore, a comparison of the results shows that obtaining the optimal transfer solution through the polynomial approximation by utilizing Cartesian coordinates is easier than using orbital elements, which normally produce strongly nonlinear equations of motion. In this paper, the Eart...
Machine Translation of Noun Phrases from Arabic to English Using Transfer-Based Approach
Directory of Open Access Journals (Sweden)
Omar Shirko
2010-01-01
Full Text Available Problem statement: Any Arabic to English Machine Translation (MT system should be capable of dealing with word order which Arabic exhibits. This poses a significant challenge to MT due to the vast number of ways to express the same sentence in Arabic. The ordering features are very important and should be carefully applied to ensure the generation of sentence in the target language. Because they apply to the target language, it should fulfill the specific requirement of this language. Mistakes in the MT output can be either the result of analysis problems at the source language level, or due to generation problem at target language level. Word order rules are crucial for the generation of sentences in the target language. They also serve as rules for the ordering of sentence constituents. These rules draw their information from the syntactic knowledge. The word order problem becomes more obvious when making machine translation between languages that have rich morphological variations. Approach: The main objective of this research is to develop a machine translation that translates Arabic noun phrases into English by using transfer-based approach. A system called Npae-Rbmt has been developed in this research. Transfer-based machine translation is one instance of rule-based machine-translation approaches and is currently one of the most widely used methods of machine translation. The idea of transfer-based machine translation it is necessary to have an intermediate representation that captures the meaning of the original sentence in order to generate the correct translation. Using advantages of transfer-based machine translation such as analysis step, the Transfer-based becomes simpler as linguistic analysis goes deeper-as the representation of analysis step becomes more abstract. In fact, a major goal of MT research is to define a level of analysis which is so deep in which transfer-based machine translation is able to do. Results: The method
Zang, Jie; Cong, Zhenhua; Chen, Xiaohan; Zhang, Xingyu; Qin, Zengguang; Liu, Zhaojun; Lu, Jianren; Wu, Dong; Fu, Qiang; Jiang, Shiqi; Zhang, Shaojun
2016-04-01
This paper presents the tunable Stokes laser characteristics of KTiOAsO4 (KTA) crystal based on stimulated polariton scattering (SPS). When the pumping laser wavelength is 1064.2 nm, the KTA Stokes wave can be discontinuously tuned from 1077.9 to 1088.4 nm with four gaps from 1079.0 to 1080.1 nm, from 1080.8 to 1082.8 nm, from 1083.6 to 1085.5 nm, and from 1085.8 to 1086.8 nm. When a frequency doubling crystal LiB3O5 (LBO) is inserted into the Stokes laser cavity, the frequency-doubled wave can be discontinuously tuned from 539.0 to 539.5 nm, from 540.1 to 540.4 nm, from 541.3 to 541.8 nm, from 542.7 to 542.9 nm and from 543.4 to 544.2 nm. With a pumping pulse energy of 130.0 mJ and an output coupler reflectivity of about 30%, the obtained maximum Stokes laser pulse energy at 1078.6 nm is 33.9 mJ and the obtained maximum frequency-doubled laser pulse energy at 543.8 nm is 15.7 mJ. By using the most probably coupled transverse optical modes obtained from the literature, the polariton refractive indexes, and the simplified polariton Sellmeier equations, the polariton dispersion curve is obtained. The formation of the Stokes frequency gaps is explained. PMID:27137044
Directory of Open Access Journals (Sweden)
V. Buchard
2011-01-01
Full Text Available Estimates of Aerosol Single Scattering Albedo (SSA from ground-based spectral measurements in the UV-visible are conducted at Villeneuve d'Ascq (VdA in France. In order to estimate this parameter, measurements of global and diffuse UV-visible solar irradiances performed under cloud-free conditions since 2003 with a spectroradiometer operated by the Laboratoire d'Optique Atmosphérique (LOA are used. The technique consists in comparing the measured irradiance values to modelled irradiances computed for various SSA. The retrieval is restricted to the 330–450 nm range to avoid ozone influence.
For validation purpose, the retrieved values of SSA at 440 nm are compared to the ones obtained from sunphotometer measurements of the AERONET/PHOTONS network available on the LOA site. The results are rather satisfying: for the period 2003–2006 the Root Mean Square (RMS of the differences is about 0.05, this value is within the uncertainty domain of retrieval of both products. Distinction between days characterized by different aerosol content, by means of the aerosol optical thickness (AOT retrieved from ground-based measurements at the same wavelength, shows that the comparisons between both products are better when AOT are higher. Indeed in case AOT are greater than 0.2, the RMS is 0.031 compared to 0.060 for days with an AOT lower than 0.2. The SSA estimated at 340 and 380 nm from ground-based spectra are also studied, though no validation can be carried out with sunphotometer data (440 nm is the shortest wavelength at which the SSA is provided by the network. The good comparisons observed at 440 nm can let assume that the SSA retrieved from spectroradiometer measurements at the two other wavelengths are also obtained with a good confidence level. Thus these values in the UV range can be used to complete aerosol data provided by AERONET/PHOTONS at VdA. Moreover they can be used for a best knowledge of the aerosol absorption that is necessary
Phenomenological analysis connecting proton-proton and antiproton-proton elastic scattering
Avila, R. F.; Campos, S. D.; Menon, M. J.; Montanha, J.
2006-01-01
Based on the behavior of the elastic scattering data, we introduce an almost model-independent parametrization for the imaginary part of the scattering amplitude, with the energy and momentum transfer dependences inferred on empirical basis and selected by rigorous theorems and bounds from axiomatic quantum field theory. The corresponding real part is analytically evaluated by means of dispersion relations, allowing connections between particle-particle and particle-antiparticle scattering. S...
An Algorithm of Inter Satellite Two-Way Time Transfer Based on Mobile Satellite
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Feijiang Huang
2013-03-01
Full Text Available Two-way time transfer is one of the most accurate time synchronization methods applied to spacecrafts and ground stations to carry out time transfer. As this method doesn’t require the knowledge of locations of two satellites in advance and it offsets the negative influence of transmission path and other additional delays, this method has boosted the time synchronization accuracy. However, in the process of time synchronization, this method demands that the aircrafts, who conduct time synchronization, could be relatively static. So it is mainly used in GEO satellites for satellite-ground two-way time transfer. Based on the establishment of mobile satellite mutual visual model, the simulation of satellite mutual visual time on mobile satellite, including IGSO (Inclined Geo Synchronous Orbit satellite and MEO (Medium Earth Orbit satellite, has been conducted. The visual time and the variation range of IGSO-MEO link distance have been gained. The characteristics of the propagation delay of two-way time transfer signals between IGSO satellite and MEO satellite varying with inter satellite range were analyzed and the rule of inter satellite clock offset varying with inter satellite range obtained with this algorithm was deduced. This study presents a inter satellite dynamic two-way time transfer algorithm based on mobile satellite. The high-accuracy inter satellite clock offset is solved through the combination of inter satellite pseudo-range polynomial fitting and clock-offset polynomial fitting. Simulation results showed that with the algorithm the inter satellite time transfer error can be controlled within 1ns. The algorithm can be used high-accuracy time transfer between mobile satellites.
Ferreira, Aires; Viana-Gomes, J.; Nilsson, Johan; Mucciolo, E. R.; Peres, N. M. R.; Castro Neto, A. H.
2011-04-01
We show that a coherent picture of the dc conductivity of monolayer and bilayer graphene at finite electronic densities emerges upon considering that strong short-range potentials are the main source of scattering in these two systems. The origin of the strong short-range potentials may lie in adsorbed hydrocarbons at the surface of graphene. The equivalence among results based on the partial-wave description of scattering, the Lippmann-Schwinger equation, and the T-matrix approach is established. Scattering due to resonant impurities close to the neutrality point is investigated via a numerical computation of the Kubo formula using a kernel polynomial method. We find that relevant adsorbate species originate impurity bands in monolayer and bilayer graphene close to the Dirac point. In the midgap region, a plateau of minimum conductivity of about e2/h (per layer) is induced by the resonant disorder. In bilayer graphene, a large adsorbate concentration can develop an energy gap between midgap and high-energy states. As a consequence, the conductivity plateau is supressed near the edges and a “conductivity gap” takes place. Finally, a scattering formalism for electrons in biased bilayer graphene, taking into account the degeneracy of the spectrum, is developed and the dc conductivity of that system is studied.
He, Hexiang; Wong, Kam Sing
2016-08-01
Wavefront shaping applied on scattering light is an efficient method for imaging through thin scattering layers. Normally, optimized modulation can be obtained by a liquid-crystal spatial light modulator (LCSLM) and CCD hardware iteration. In this paper, an improved method for such an optimization process is introduced. The core of the proposed method is to firstly detect the disturbed wavefront, and then to calculate the modulation phase pattern by computer simulation. Fast processing speed resulting in high quality images have been achieved with this new approach. Using supposition of conjugated phase of the scattering wavefront and a Fresnel phase scheme, more than two orders of magnitude improvement in processing speed for imaging restoration was shown compared to the LCSLM-CCD iteration method.
Lü, X.; Schrottke, L.; Grahn, H. T.
2016-06-01
We present scattering rates for electrons at longitudinal optical phonons within a model completely formulated in the Fourier domain. The total intersubband scattering rates are obtained by averaging over the intrasubband electron distributions. The rates consist of the Fourier components of the electron wave functions and a contribution depending only on the intersubband energies and the intrasubband carrier distributions. The energy-dependent part can be reproduced by a rational function, which allows for the separation of the scattering rates into a dipole-like contribution, an overlap-like contribution, and a contribution which can be neglected for low and intermediate carrier densities of the initial subband. For a balance between accuracy and computation time, the number of Fourier components can be adjusted. This approach facilitates an efficient design of complex heterostructures with realistic, temperature- and carrier density-dependent rates.
Average-Atom Model for X-ray Scattering from Warm Dense Matter
Johnson, W R; Cheng, K T
2012-01-01
A scheme for analyzing Thomson scattering of x-rays by warm dense matter, based on the average-atom model, is developed. Emphasis is given to x-ray scattering by bound electrons. Contributions to the scattered x-ray spectrum from elastic scattering by electrons moving with the ions and from inelastic scattering by free and bound electrons are evaluated using parameters (chemical potential, average ionic charge, free electron density, bound and continuum wave functions, and occupation numbers) taken from the average-atom model. The resulting scheme provides a relatively simple diagnostic for use in connection with x-ray scattering measurements. Applications are given to dense hydrogen, beryllium, aluminum, titanium, and tin plasmas. At high momentum transfer, contributions from inelastic scattering by bound electrons are dominant features of the scattered x-ray spectrum for aluminum, titanium, and tin.
Effects of creating video-based modeling examples on learning and transfer
Hoogerheide, Vincent; Loyens, Sofie M M; van Gog, Tamara
2014-01-01
Two experiments investigated whether acting as a peer model for a video-based modeling example, which entails studying a text with the intention to explain it to others and then actually explaining it on video, would foster learning and transfer. In both experiments, novices were instructed to study
A Computer-Based Simulation for Teaching Heat Transfer across a Woody Stem
Maixner, Michael R.; Noyd, Robert K.; Krueger, Jerome A.
2010-01-01
To assist student understanding of heat transfer through woody stems, we developed an instructional package that included an Excel-based, one-dimensional simulation model and a companion instructional worksheet. Guiding undergraduate botany students to applying principles of thermodynamics to plants in nature is fraught with two main obstacles:…
Analysis of a Knowledge-Management-Based Process of Transferring Project Management Skills
Ioi, Toshihiro; Ono, Masakazu; Ishii, Kota; Kato, Kazuhiko
2012-01-01
Purpose: The purpose of this paper is to propose a method for the transfer of knowledge and skills in project management (PM) based on techniques in knowledge management (KM). Design/methodology/approach: The literature contains studies on methods to extract experiential knowledge in PM, but few studies exist that focus on methods to convert…
Directory of Open Access Journals (Sweden)
LIU Ketang
2013-02-01
Full Text Available Functional graphite oxide materials were synthesized through the Hummers chemical oxidation of graphite.Heterogeneous catalyst was prepared via direct grafting diamine-based chiral ligand to graphite oxide followed by the complexation with organorhodium complex.Such a chiral rhodium catalyst exhibited high catalytic activity and enantioselectivity in asymmetric transfer hydrogenation of aromatic ketones in aqueous medium under mild condition.
Zhang, Yan; Zhang, Limin; Jin, Meng; Zhao, Huijuan; Gao, Feng; Li, Jiao
2015-03-01
In diffuse florescence tomography (DFT), the radiative transfer equation (RTE) and its P1 approximation, i.e. the diffuse equation (DE), have been used as the forward models. Since the assumptions of the diffusion approximation are not valid in particular regions of biological tissue which are close to the collimated light sources and boundaries, not scattering dominated or having void-like sub-domains, the RTE-based DFT methodology has become a focus of investigation. Therefore, we present a RTE-based featured-data scheme for time-domain DFT, which combines the discrete solidangle- element method and the finite element method to obtain numerical solutions of the Laplace-transformed 2D timedomain RTE, with the natural boundary condition and collimating light source model. The scheme is validated using the measurement data from phantom and in-vivo small-animal experiments compared to the DE-based scheme.
Neutron signal transfer analysis
Pleinert, H; Lehmann, E
1999-01-01
A new method called neutron signal transfer analysis has been developed for quantitative determination of hydrogenous distributions from neutron radiographic measurements. The technique is based on a model which describes the detector signal obtained in the measurement as a result of the action of three different mechanisms expressed by signal transfer functions. The explicit forms of the signal transfer functions are determined by Monte Carlo computer simulations and contain only the distribution as a variable. Therefore an unknown distribution can be determined from the detector signal by recursive iteration. This technique provides a simple and efficient tool for analysis of this type while also taking into account complex effects due to the energy dependency of neutron interaction and single and multiple scattering. Therefore this method provides an efficient tool for precise quantitative analysis using neutron radiography, as for example quantitative determination of moisture distributions in porous buil...
International Nuclear Information System (INIS)
A depth discrimination method is devised based on a multirow linear array detector for push-broom Compton scatter imaging. Two or more rows of detector modules are placed at different positions towards a sample. An improved parallel-hole collimator is fixed in front of the modules to restrict their fields of view. The depth information could be indicated by comparing the signal differences. In addition, an available detector and several related simulations using GEANT4 are given to support the method well. - Highlights: • We devise a depth discrimination method for push-broom Compton scatter imaging. • Depth of sample is indicated by comparing signal proportions of different modules. • The depth discrimination is linked to different measurement geometries. • A multirow linear array detector based on XP1452 and LYSO was developed. • Simulation model is built using GEANT4 to support the method well
Wave scattering theory a series approach based on the Fourier transformation
Eom, Hyo J
2001-01-01
The book provides a unified technique of Fourier transform to solve the wave scattering, diffraction, penetration, and radiation problems where the technique of separation of variables is applicable. The book discusses wave scattering from waveguide discontinuities, various apertures, and coupling structures, often encountered in electromagnetic, electrostatic, magnetostatic, and acoustic problems. A system of simultaneous equations for the modal coefficients is formulated and the rapidly-convergent series solutions amenable to numerical computation are presented. The series solutions find practical applications in the design of microwave/acoustic transmission lines, waveguide filters, antennas, and electromagnetic interference/compatibilty-related problems.
Czech Academy of Sciences Publication Activity Database
Mukherji, D.; Wehr, J.; Strunz, Pavel; Gilles, R.; Hofmann, M.; Hoelzel, M.; Roesler, J.
München : Technische Universität München, 2012 - (Carsughi, F.; Lommatzsch, I.; Neuhaus, J.). s. 34-34 [4th User Meeting at the FRM II. 23.03.2012-23.03.2012, Garching bei München] Institutional support: RVO:61389005 Keywords : Co-Re based alloys * neutron scattering * high temeperature Subject RIV: BM - Solid Matter Physics ; Magnetism http://cdn.frm2.tum.de/fileadmin/stuff/ information /UserOffice/UM2012_Booklet_lr.pdf
Monte-Carlo simulation of an ultra small-angle neutron scattering instrument based on Soller slits
Energy Technology Data Exchange (ETDEWEB)
Rieker, T. [Univ. of New Mexico, Albuquerque, NM (United States); Hubbard, P. [Sandia National Labs., Albuquerque, NM (United States)
1997-09-01
Monte Carlo simulations are used to investigate an ultra small-angle neutron scattering instrument for use at a pulsed source based on a Soller slit collimator and analyzer. The simulations show that for a q{sub min} of {approximately}le-4 {angstrom}{sup -1} (15 {angstrom} neutrons) a few tenths of a percent of the incident flux is transmitted through both collimators at q=0.
Rusiecki, Philip R.
2015-01-01
Approved for public release; distribution is unlimited Heavy oxide inorganic scintillators may prove viable in the detection of fast neutrons based on the mechanism of inelastic neutron scattering. A candidate set of crystals incorporating constituents of heavy atomic mass, namely bismuth germinate (BGO), zinc tungstate (ZWO), cadmium tungstate (CWO), lead tungstate (PWO), lutetium-gadolinium orthosilicate activated with cerium (LGSO:Ce) and lutetium-aluminum garnet with cerium (LuAG:Ce), ...
Diffuse neutron scattering signatures of rough films
International Nuclear Information System (INIS)
Patterns of diffuse neutron scattering from thin films are calculated from a perturbation expansion based on the distorted-wave Born approximation. Diffuse fringes can be categorised into three types: those that occur at constant values of the incident or scattered neutron wavevectors, and those for which the neutron wavevector transfer perpendicular to the film is constant. The variation of intensity along these fringes can be used to deduce the spectrum of surface roughness for the film and the degree of correlation between the film's rough surfaces
Platzer, K.-H.; Hirsch, C.; Metzger, D. E.; Wittig, S.
1992-05-01
The experimental technique presented is designed to obtain detailed local heat transfer data on both stationary as well as rotating disk-cavity surfaces applicable to gas turbines. The method employed utilizes thin coatings of thermochromic liquid crystals (TLC) as surface temperature indicators under aerodynamically steady but thermally transient experimental conditions. The color display of the liquid crystals is monitored by a video camera. The video signals are captured in real time by a computer-based color recognition system to extract areal temperature and heat transfer information. Some typical results are presented and compared with literature data to illustrate the potential of the system.
Design of interface for industrial CT data transfers system base on ARM9 and FPGA
International Nuclear Information System (INIS)
A design base on ARM9 microprocessor produced by samsung company and FPGA produced by altera company. Details on hardware connection technology between S3C2410 and FPGA via AHB bus. The design also introduce realization of the timing control of AHB bus in QuartusII environment and drivers development for AHB bus under the Linux operation system. The results realize the data transfer steadily and rapidly in Industrial CT Data Transfers System. The design display advantage of ARM and FPGA. And also give good instructions for other similar design on dual core. (authors)
Charge-transfer complexes of pyrimidine Schiff bases with aromatic nitro compounds
Issa, Yousry M.; El Ansary, A. L.; Sherif, O. E.; Hassib, H. B.
2011-08-01
Charge-transfer (CT) complexes of pyrimidine Schiff bases, derived from condensation of 2-aminopyrimidine and substituted benzaldehydes, with some aromatic polynitro compounds were prepared and investigated using IR, UV, visible and 1H NMR spectroscopy. For all solid complexes, the main interaction between the donor and acceptor molecules takes place through the π-π* interaction. Strong and some weak acidic acceptors, in addition interact through proton transfer from the acceptor molecule to the basic centre of the electron donor. Also, an n-π* transition was detected in some complexes.
Experience in the transfer of oil sludge from Kemaman supply base (KSB) Terengganu
International Nuclear Information System (INIS)
EPMI and MINT had signed a contract for transferring 2400 drums containing oil sludge waste from Kemaman Supply Base (KSB), Terengganu to MINT, Bangi with a cost of RM 2.5 million. The work was done in two stages; the first stage involved 800 drums and the second stage involved 1600 drums. The preparation and implementation work involved application to obtain approval from the Atomic Energy Licensing Board (AELB) and Department of Environment (DOE) as the transportation has to comply with transport regulations for radioactive and toxic waste, appointing transport company, providing information and briefing to supervisors / workers regarding radiation as well as other safety aspects during transfer of waste. (Author)
Wu, Q.; Li, Y. H.; Gao, N.; Yang, F.; Chen, Y. Q.; Fang, K.; Zhang, Y. W.; Chen, H.
2015-03-01
In this letter, a potential way to transfer power wirelessly based on magnetic metamaterials (MMs) assembled by ultra-subwavelength meta-atoms is proposed. Frequency-domain simulation and experiments are performed for accurately obtaining effective permeability of magnetic metamaterials. The results demonstrate that MMs possess great power for enhancing the wireless power transfer efficiency between two non-resonant coils. Further investigations on the magnetic-field distribution demonstrate that a large-area flattened magnetic field in near range can be effectively realized, exhibiting great flexibility in assembling.
Measuring the heat-transfer coefficient of nanofluid based on copper oxide in a cylindrical channel
Guzei, D. V.; Minakov, A. V.; Rudyak, V. Ya.; Dekterev, A. A.
2014-03-01
The heat-transfer coefficient of nanofluid during its flow in a cylindrical channel is studied experimentally. The studied nanofluid was prepared based on distilled water and CuO nanoparticles. Nanoparticle concentration varied in the range from 0.25 to 2% in the volume. The nanofluid was stabilized using a xanthane gum biopolymer the mass concentration of which did not exceed 0.03%. Considerable intensification of heat transfer was found. The nanofluid appeared to be Newtonian when particle concentrations exceeded 0.25%. Estimates for rheological parameters of the nanofluid and thermal conductivity coefficient have been obtained.
GPU-BASED MONTE CARLO DUST RADIATIVE TRANSFER SCHEME APPLIED TO ACTIVE GALACTIC NUCLEI
International Nuclear Information System (INIS)
A three-dimensional parallel Monte Carlo (MC) dust radiative transfer code is presented. To overcome the huge computing-time requirements of MC treatments, the computational power of vectorized hardware is used, utilizing either multi-core computer power or graphics processing units. The approach is a self-consistent way to solve the radiative transfer equation in arbitrary dust configurations. The code calculates the equilibrium temperatures of two populations of large grains and stochastic heated polycyclic aromatic hydrocarbons. Anisotropic scattering is treated applying the Heney-Greenstein phase function. The spectral energy distribution (SED) of the object is derived at low spatial resolution by a photon counting procedure and at high spatial resolution by a vectorized ray tracer. The latter allows computation of high signal-to-noise images of the objects at any frequencies and arbitrary viewing angles. We test the robustness of our approach against other radiative transfer codes. The SED and dust temperatures of one- and two-dimensional benchmarks are reproduced at high precision. The parallelization capability of various MC algorithms is analyzed and included in our treatment. We utilize the Lucy algorithm for the optical thin case where the Poisson noise is high, the iteration-free Bjorkman and Wood method to reduce the calculation time, and the Fleck and Canfield diffusion approximation for extreme optical thick cells. The code is applied to model the appearance of active galactic nuclei (AGNs) at optical and infrared wavelengths. The AGN torus is clumpy and includes fluffy composite grains of various sizes made up of silicates and carbon. The dependence of the SED on the number of clumps in the torus and the viewing angle is studied. The appearance of the 10 μm silicate features in absorption or emission is discussed. The SED of the radio-loud quasar 3C 249.1 is fit by the AGN model and a cirrus component to account for the far-infrared emission.
International Nuclear Information System (INIS)
We describe a new algorithm for solving the coupled frequency-integrated transfer equation and the equations of magnetohydrodynamics in the regime that light-crossing time is only marginally shorter than dynamical timescales. The transfer equation is solved in the mixed frame, including velocity-dependent source terms accurate to O(v/c). An operator split approach is used to compute the specific intensity along discrete rays, with upwind monotonic interpolation used along each ray to update the transport terms, and implicit methods used to compute the scattering and absorption source terms. Conservative differencing is used for the transport terms, which ensures the specific intensity (as well as energy and momentum) are conserved along each ray to round-off error. The use of implicit methods for the source terms ensures the method is stable even if the source terms are very stiff. To couple the solution of the transfer equation to the MHD algorithms in the ATHENA code, we perform direct quadrature of the specific intensity over angles to compute the energy and momentum source terms. We present the results of a variety of tests of the method, such as calculating the structure of a non-LTE atmosphere, an advective diffusion test, linear wave convergence tests, and the well-known shadow test. We use new semi-analytic solutions for radiation modified shocks to demonstrate the ability of our algorithm to capture the effects of an anisotropic radiation field accurately. Since the method uses explicit differencing of the spatial operators, it shows excellent weak scaling on parallel computers
International Nuclear Information System (INIS)
This paper proposes a hybrid method based on the forward–backward method (FBM) and the reciprocity theorem (RT) for evaluating the scattering field from dielectric rough surface with a 2D target above it. Here, the equivalent electric/magnetic current densities on the rough surface as well as the scattering field from it are numerically calculated by FBM, and the scattered field from the isolated target is obtained utilizing the method of moments (MOM). Meanwhile, the rescattered coupling interactions between the target and the surface are evaluated employing the combination of FBM and RT. Our hybrid method is first validated by available MOM results. Then, the functional dependences of bistatic and monostatic scattering from the target above rough surface upon the target altitude, incident and scattering angles are numerically simulated and discussed. This study presents a numerical description for the scattering mechanism associated with rescattered coupling interactions between a target and an underlying randomly rough surface. (classical areas of phenomenology)
Socioeconomics of Individual Transferable Quotas and Community-Based Fishery Management
Copes, Parzival; Charles, Anthony T.
2004-01-01
In many fisheries around the world, the failures of centralized, top-down management have produced a shift toward co-managementÂ—collaboration and sharing of decision making between government and stakeholders. This trend has led to a major debate between two very different co-management approachesÂ—community-based fishery management and market-based individual transferable quota management. This paper examines the debate over the relative merits of these models and undertakes a socioeconomic...
Input-output Transfer Function Analysis of a Photometer Circuit Based on an Operational Amplifier
Wilmar Hernandez
2008-01-01
In this paper an input-output transfer function analysis based on the frequency response of a photometer circuit based on operational amplifier (op amp) is carried out. Op amps are universally used in monitoring photodetectors and there are a variety of amplifier connections for this purpose. However, the electronic circuits that are usually used to carry out the signal treatment in photometer circuits introduce some limitations in the performance of the photometers that influence the selecti...
Polarized Proton Nucleus Scattering
Kopeliovich, B. Z.; Trueman, T. L.
2000-01-01
We show that, to a very good approximation, the ratio of the spin-flip to the non-flip parts of the elastic proton-nucleus amplitude is the same as for proton-nucleon scattering at very high energy. The result is used to do a realistic calculation of the analyzing power A_N for pC scattering in the Coulomb-nuclear interference (CNI) region of momentum transfer.
Freedman, A.; Onasch, T. B.; Renbaum-Wollf, L.; Lambe, A. T.; Davidovits, P.; Kebabian, P. L.
2015-12-01
Accurate, as compared to precise, measurement of aerosol absorption has always posed a significant problem for the particle radiative properties community. Filter-based instruments do not actually measure absorption but rather light transmission through the filter; absorption must be derived from this data using multiple corrections. The potential for matrix-induced effects is also great for organic-laden aerosols. The introduction of true in situ measurement instruments using photoacoustic or photothermal interferometric techniques represents a significant advance in the state-of-the-art. However, measurement artifacts caused by changes in humidity still represent a significant hurdle as does the lack of a good calibration standard at most measurement wavelengths. And, in the absence of any particle-based absorption standard, there is no way to demonstrate any real level of accuracy. We, along with others, have proposed that under the circumstance of low single scattering albedo (SSA), absorption is best determined by difference using measurement of total extinction and scattering. We discuss a robust, compact, field deployable instrument (the CAPS PMssa) that simultaneously measures airborne particle light extinction and scattering coefficients and thus the single scattering albedo (SSA) on the same sample volume. The extinction measurement is based on cavity attenuated phase shift (CAPS) techniques as employed in the CAPS PMex particle extinction monitor; scattering is measured using integrating nephelometry by incorporating a Lambertian integrating sphere within the sample cell. The scattering measurement is calibrated using the extinction measurement of non-absorbing particles. For small particles and low SSA, absorption can be measured with an accuracy of 6-8% at absorption levels as low as a few Mm-1. We present new results of the measurement of the mass absorption coefficient (MAC) of soot generated by an inverted methane diffusion flame at 630 nm. A value
The analysis of nano structures based on small angle scattering of neutrons
International Nuclear Information System (INIS)
The paper describes the technology of small angle neutron scattering from neutron beam cooling to beam focusing and image processing. The applicability of the method is illustrated by sodium bubble analysis in tungsten, and investigation of the the effect of microbial transglutamase on casein micellas.
A method for moisture measurement in porous media based on epithermal neutron scattering.
El Abd, A
2015-11-01
A method for moisture measurement in porous media was proposed. A wide beam of epithermal neutrons was obtained from a Pu-Be neutron source immersed in a cylinder made of paraffin wax. (3)He detectors (four or six) arranged in the backward direction of the incident beam were used to record scattered neutrons from investigated samples. Experiments of water absorption into clay and silicate bricks, and a sand column were investigated by neutron scattering. While the samples were absorbing water, scattered neutrons were recorded from fixed positions along the water flow direction. It was observed that, at these positions scattered neutrons increase as the water uptake increases. Obtained results are discussed in terms of the theory of macroscopic flow in porous media. It was shown that, the water absorption processes were Fickian and non Fickian in the sand column and brick samples, respectively. The advantages of applying the proposed method to study fast as well as slow flow processes in porous media are discussed. PMID:26298060
International Nuclear Information System (INIS)
A new way of α-particle diagnostics enabling by means of laser scattering to determine an average energy and relative concentration of α-particles with high space resolution, is discussed. The technique is based on scattering of CO2-laser radiation on plasma fluctuations of Bernstein ion wave type with frequencies exceeding frequency of low hybrid resonance
Cellular automata-based artificial life system of horizontal gene transfer
Directory of Open Access Journals (Sweden)
Ji-xin Liu
2016-02-01
Full Text Available Mutation and natural selection is the core of Darwin's idea about evolution. Many algorithms and models are based on this idea. However, in the evolution of prokaryotes, more and more researches have indicated that horizontal gene transfer (HGT would be much more important and universal than the authors had imagined. Owing to this mechanism, the prokaryotes not only become adaptable in nearly any environment on Earth, but also form a global genetic bank and a super communication network with all the genes of the prokaryotic world. Under this background, they present a novel cellular automata model general gene transfer to simulate and study the vertical gene transfer and HGT in the prokaryotes. At the same time, they use Schrodinger's life theory to formulate some evaluation indices and to discuss the intelligence and cognition of prokaryotes which is derived from HGT.
3-Coil resonance-based wireless power transfer system for implantable electronic
Yi, Ying
2013-05-01
This paper presents a 3-coil resonance-based wireless power transfer (R-WPT) system using a single layer of inductor coil windings, in a pancake configuration, in order to obtain a compact system for implantable electronic applications. A theoretical analysis and experimental measurements in terms of quality factor Q and power transfer efficiency (PTE), was done. Our proposed 3-coil scheme can achieve a high PTE with a resonance frequency of 2.46 MHz over a transfer distance of up to 30 mm, by using two 15-mm radius implant coils. The achieved experimental PTE is more than 85%at a 5 mm separation distance, and about 50% PTE at a distance of 20 mm. © 2013 IEEE.
Risk Contagion in Chinese Banking Industry: A Transfer Entropy-Based Analysis
Directory of Open Access Journals (Sweden)
Jianping Li
2013-12-01
Full Text Available What is the impact of a bank failure on the whole banking industry? To resolve this issue, the paper develops a transfer entropy-based method to determine the interbank exposure matrix between banks. This method constructs the interbank market structure by calculating the transfer entropy matrix using bank stock price sequences. This paper also evaluates the stability of Chinese banking system by simulating the risk contagion process. This paper contributes to the literature on interbank contagion mainly in two ways: it establishes a convincing connection between interbank market and transfer entropy, and exploits the market information (stock price rather than presumptions to determine the interbank exposure matrix. Second, the empirical analysis provides an in depth understanding of the stability of the current Chinese banking system.
Efficient Synchronization of Dipolarly Coupled Vortex-Based Spin Transfer Nano-Oscillators
Locatelli, Nicolas; Hamadeh, Abbass; Abreu Araujo, Flavio; Belanovsky, Anatoly D.; Skirdkov, Petr N.; Lebrun, Romain; Naletov, Vladimir V.; Zvezdin, Konstantin A.; Muñoz, Manuel; Grollier, Julie; Klein, Olivier; Cros, Vincent; de Loubens, Grégoire
2015-11-01
Due to their nonlinear properties, spin transfer nano-oscillators can easily adapt their frequency to external stimuli. This makes them interesting model systems to study the effects of synchronization and brings some opportunities to improve their microwave characteristics in view of their applications in information and communication technologies and/or to design innovative computing architectures. So far, mutual synchronization of spin transfer nano-oscillators through propagating spinwaves and exchange coupling in a common magnetic layer has been demonstrated. Here we show that the dipolar interaction is also an efficient mechanism to synchronize neighbouring oscillators. We experimentally study a pair of vortex-based spin transfer nano-oscillators, in which mutual synchronization can be achieved despite a significant frequency mismatch between oscillators. Importantly, the coupling efficiency is controlled by the magnetic configuration of the vortices, as confirmed by an analytical model and micromagnetic simulations highlighting the physics at play in the synchronization process.
Phonon Boltzmann equation-based discrete unified gas kinetic scheme for multiscale heat transfer
Guo, Zhaoli
2016-01-01
Numerical prediction of multiscale heat transfer is a challenging problem due to the wide range of time and length scales involved. In this work a discrete unified gas kinetic scheme (DUGKS) is developed for heat transfer in materials with different acoustic thickness based on the phonon Boltzmann equation. With discrete phonon direction, the Boltzmann equation is discretized with a second-order finite-volume formulation, in which the time-step is fully determined by the Courant-Friedrichs-Lewy (CFL) condition. The scheme has the asymptotic preserving (AP) properties for both diffusive and ballistic regimes, and can present accurate solutions in the whole transition regime as well. The DUGKS is a self-adaptive multiscale method for the capturing of local transport process. Numerical tests for both heat transfers with different Knudsen numbers are presented to validate the current method.
Dong, Haiyun; Wei, Yanhui; Zhang, Wei; Wei, Cong; Zhang, Chunhuan; Yao, Jiannian; Zhao, Yong Sheng
2016-02-01
Wavelength tunable micro/nanolasers are indispensable components for various photonic devices. Here, we report broadband tunable microlasers built by incorporating a highly polarized organic intramolecular charge-transfer (ICT) compound with a supramolecular host. The spatial confinement of the ICT dye generates an optimized energy level system that favors controlled population distribution between the locally excited (LE) state and the twisted intramolecular charge-transfer (TICT) state, which is beneficial for significantly broadening the tailorable gain region. As a result, we realized a wide tuning of lasing wavelength in the organic supramolecular microcrystals based on temperature-controlled population transfer from the LE to TICT state. The results will provide a useful enlightenment for the rational design of miniaturized lasers with desired performances. PMID:26756966
Das, Rabindra Nath
2007-01-01
In this paper, the new forms obtained for Chandrasekhar's H- function in Radiative Transfer by one of the authors both for non-conservative and conservative cases for isotropic scattering in a semi-infinite plane parallel atmosphere are used to obtain exclusively new forms for the first and second derivatives of H-function . The numerics for evaluation of zero of dispersion function, for evaluation of H-function and its derivatives and its zeroth, the first and second moments are outlined. Those are used to get ready and accurate extensive tables of H-function and its derivatives, pole and moments for different albedo for scattering by iteration and Simpson's one third rule . The schemes for interpolation of H-function for any arbitrary value of the direction parameter for a given albedo are also outlined. Good agreement has been observed in checks with the available results within one unit of ninth decimal
Proton inelastic scattering cannot be predicted from electron scattering results
International Nuclear Information System (INIS)
The prediction of proton inelastic scattering based on transition densities determined from electron scattering is critically examined. As an example, for the O3+ state in 16O, it is shown that abnormal parity amplitudes prevent an unambiguous prediction, and largely different results can be found for proton scattering while electron scattering results are identical
Silica-gold bilayer-based transfer of focused ion beam-fabricated nanostructures
Wu, Xiaofei; Geisler, Peter; Krauss, Enno; Kullock, René; Hecht, Bert
2015-10-01
The demand for using nanostructures fabricated by focused ion beam (FIB) on delicate substrates or as building blocks for complex devices motivates the development of protocols that allow FIB-fabricated nanostructures to be transferred from the original substrate to the desired target. However, transfer of FIB-fabricated nanostructures is severely hindered by FIB-induced welding of structure and substrate. Here we present two (ex and in situ) transfer methods for FIB-fabricated nanostructures based on a silica-gold bilayer evaporated onto a bulk substrate. Utilizing the poor adhesion between silica and gold, the nanostructures can be mechanically separated from the bulk substrate. For the ex situ transfer, a spin-coated poly(methyl methacrylate) film is used to carry the nanostructures so that the bilayer can be etched away after being peeled off. For the in situ transfer, using a micro-manipulator inside the FIB machine, a cut-out piece of silica on which a nanostructure has been fabricated is peeled off from the bulk substrate and thus carries the nanostructure to a target substrate. We demonstrate the performance of both methods by transferring plasmonic nano-antennas fabricated from single-crystalline gold flakes by FIB milling to a silicon wafer and to a scanning probe tip.The demand for using nanostructures fabricated by focused ion beam (FIB) on delicate substrates or as building blocks for complex devices motivates the development of protocols that allow FIB-fabricated nanostructures to be transferred from the original substrate to the desired target. However, transfer of FIB-fabricated nanostructures is severely hindered by FIB-induced welding of structure and substrate. Here we present two (ex and in situ) transfer methods for FIB-fabricated nanostructures based on a silica-gold bilayer evaporated onto a bulk substrate. Utilizing the poor adhesion between silica and gold, the nanostructures can be mechanically separated from the bulk substrate. For the ex
Dixit, Manish Kumar; Pandey, Vinay Kumar; Dubey, Mrigendra
2016-04-13
Three l-tartaric acid based symmetrical A-π-D-chiral-D-π-A type structural isomeric nitrobenzylidenes () have been synthesized with intent to achieve isomer specific metallogels with intramolecular charge transfer properties. Alkali metal ions in these systems not only trigger charge transfer but also play a vital role in gelation. The presence of intramolecular rather than intermolecular charge transfer as well as aggregation has been well established by various kinds of experiments using UV-vis, CD, (1)H NMR, DFT and crystallography techniques. The role of alkali metal ions in triggering ICT was proved by titration with their respective crown ethers. Notably, Na(+) afforded twisted fiber morphology whilst Li(+) gave merely long range fibers. The true gel phase material was proved by detailed rheological studies. PMID:26974120
Yang, Defu; Chen, Xueli; Peng, Zhen; Wang, Xiaorui; Ripoll, Jorge; Wang, Jing; Liang, Jimin
2013-01-01
Modeling light propagation in the whole body is essential and necessary for optical imaging. However, non-scattering, low-scattering and high absorption regions commonly exist in biological tissues, which lead to inaccuracy of the existing light transport models. In this paper, a novel hybrid light transport model that couples the simplified spherical harmonics approximation (SPN) with the radiosity theory (HSRM) was presented, to accurately describe light transport in turbid media with non-s...
Tahat, Amani; Martí Rabassa, Jordi; Khwaldeh, Ali; Tahat, Kaher
2014-01-01
In computational physics proton transfer phenomena could be viewed as pattern classification problems based on a set of input features allowing to classify the proton motion into two categories: transfer‘occurred’and transfer‘not occurred’. The goal of this paper is to evaluate the use of artificial neural networks in the classification of proton transfer events, based on the feed-forward back propagation neural network, used as a classifier to distinguish between the two transfer cases. In t...
International Nuclear Information System (INIS)
Optical coherence tomography (OCT) has been demonstrated to be a powerful tool for noninvasive, real-time oral cancer diagnosis. However, in previous reports, OCT has still been found to be difficult to use in the diagnosis of oral precancerous stages, including mild dysplasia and moderate dysplasia. In clinical applications, early diagnosis and treatment of oral cancer can greatly improve the survival rate. Therefore, in this study, we propose a new approach to differentiate the oral precancerous stages based on the evaluation of the optical scattering properties of the epithelial layer, which is where the dysplastic cells start to develop in the precancerous stages. Instead of using exponential decay fitting to evaluate the scattering properties of mucosal tissues based on the Beer–Lambert law, linear fitting of the OCT depth intensity is used to evaluate the scattering properties of normal and dysplastic cells. From the statistical results of the linear fitting, the slope, a, can be an effective indicator to discriminate healthy mucosa and moderate dysplasia when an a value equal to zero is the threshold value, and the intercept, b, can be used to differentiate healthy and dysplastic mucosae, as well as mild and moderate dysplasia, when b values of 0.15 and 0.18 are used as the threshold values, respectively. Furthermore, this approach is also applied to the determination of the safe margin between normal and abnormal mucosae, making it possible to provide real-time, in vivo inspection during oral maxillofacial surgery. (paper)
International Nuclear Information System (INIS)
To date, the light scattering models of snow consider very little about the real snow microstructures. The ideal spherical or other single shaped particle assumptions in previous snow light scattering models can cause error in light scattering modeling of snow and further cause errors in remote sensing inversion algorithms. This paper tries to build up a snow polarized reflectance model based on bicontinuous medium, with which the real snow microstructure is considered. The accurate specific surface area of bicontinuous medium can be analytically derived. The polarized Monte Carlo ray tracing technique is applied to the computer generated bicontinuous medium. With proper algorithms, the snow surface albedo, bidirectional reflectance distribution function (BRDF) and polarized BRDF can be simulated. The validation of model predicted spectral albedo and bidirectional reflectance factor (BRF) using experiment data shows good results. The relationship between snow surface albedo and snow specific surface area (SSA) were predicted, and this relationship can be used for future improvement of snow specific surface area (SSA) inversion algorithms. The model predicted polarized reflectance is validated and proved accurate, which can be further applied in polarized remote sensing. -- Highlights: • Bicontinuous random medium were used for real snow microstructure modeling. • Photon tracing technique with polarization status tracking ability was applied. • SSA–albedo relationship of snow is close to that of sphere based medium. • Validation of albedo and BRDF showed good results. • Validation of polarized reflectance showed good agreement with experiment data
Tsai, M. T.; Lee, J. D.; Lee, Y. J.; Lee, C. K.; Jin, H. L.; Chang, F. Y.; Hu, K. Y.; Wu, C. P.; Chiang, C. P.; Yang, C. C.
2013-04-01
Optical coherence tomography (OCT) has been demonstrated to be a powerful tool for noninvasive, real-time oral cancer diagnosis. However, in previous reports, OCT has still been found to be difficult to use in the diagnosis of oral precancerous stages, including mild dysplasia and moderate dysplasia. In clinical applications, early diagnosis and treatment of oral cancer can greatly improve the survival rate. Therefore, in this study, we propose a new approach to differentiate the oral precancerous stages based on the evaluation of the optical scattering properties of the epithelial layer, which is where the dysplastic cells start to develop in the precancerous stages. Instead of using exponential decay fitting to evaluate the scattering properties of mucosal tissues based on the Beer-Lambert law, linear fitting of the OCT depth intensity is used to evaluate the scattering properties of normal and dysplastic cells. From the statistical results of the linear fitting, the slope, a, can be an effective indicator to discriminate healthy mucosa and moderate dysplasia when an a value equal to zero is the threshold value, and the intercept, b, can be used to differentiate healthy and dysplastic mucosae, as well as mild and moderate dysplasia, when b values of 0.15 and 0.18 are used as the threshold values, respectively. Furthermore, this approach is also applied to the determination of the safe margin between normal and abnormal mucosae, making it possible to provide real-time, in vivo inspection during oral maxillofacial surgery.
International Nuclear Information System (INIS)
The feasibility of an ultrasonic nondestructive evaluation method for the properties of a single-fiber interphase is investigated theoretically. The nondestructive characterization method of the interphase suggested in this study is to utilize the frequency-domain characteristics of stresses in the scattered waves. It has been observed that the peaks and valleys in the frequency response of ultrasonic scattered waves are affected in their locations and magnitudes significantly by the interphase properties. To assess the feasibility of solving the inverse problem, a neural network model is constructed based on the theoretically computed database containing the interphase properties and the corresponding frequency response characteristics. It is shown that the neural network constructed in this study is capable of estimating the intenhase properties with good accuracy in most cases. This implies that the method suggested in this study is feasible and is worth attempting in an experimental study in the future.
Zhang, Xi; Jiang, Hongrui
2015-03-01
Photo-self-charging cells (PSCs) are compact devices with dual functions of photoelectric conversion and energy storage. By introducing a scattering layer in polymer-based quasi-solid-state dye-sensitized solar cells, two-electrode PSCs with highly compact structure were obtained. The charge storage function stems from the formed ion channel network in the scattering layer/polymer electrolyte system. Both the photoelectric conversion and the energy storage functions are integrated in only the photoelectrode of such PSCs. This design of PSC could continuously output power as a solar cell with considerable efficiency after being photo-charged. Such PSCs could be applied in highly-compact mini power devices.
Boiling heat transfer phenomenon base on the event of loca and severe accident
International Nuclear Information System (INIS)
Research and development base on TMI-2 NPP accident mostly directed to vessel and core performance. The majority of research was conducted which aimed on boiling heat transfer phenomenon, begin by loss of coolant accident (LOCA) until severe accident, in which core meltdown. Study on boiling heat transfer has been done by simulation on core bottom re-flooding process and a narrow gap cooling. The results of experimental research which was conducted by BATAN concerning LOCA and severe accident are giving a clearly picture, in how boiling heat transfer phenomenon was occurs during sequent of nuclear reactors accident, especially TMI-2 accident. The mapping of heat transfer base on transient temperature data was created in boiling curve form which was shown the differences of heat flux in three boiling regimes, both in pool boiling and flow boiling. The experimental simulation of LOCA shown that the CHF value (67.31 kW/m2 ) is small than the CHF value of severe accident (262 kW/m2). (author)
Yokokawa, Takumi; Nishidate, Izumi
2016-04-01
We investigate a method to evaluate light-scattering properties and chromophore concentrations in human skin tissue through diffuse reflectance spectroscopy using the reflectance signals acquired at isosbestic wavelengths of hemoglobin (420, 450, 500, and 585 nm). In the proposed method, Monte Carlo simulation-based empirical formulas are used to specify the scattering parameters of skin tissue, such as the scattering amplitude a and the scattering power b, as well as the concentration of melanin C m and the total blood concentration C tb. The use of isosbestic wavelengths of hemoglobin enables the values of C m, C tb, a, and b to be estimated independently of the oxygenation of hemoglobin. The spectrum of the reduced scattering coefficient is reconstructed from the scattering parameters. Experiments using in vivo human skin tissues were performed to confirm the feasibility of the proposed method for evaluating the changes in scattering properties and chromophore concentrations in skin tissue. The experimental results revealed that light scattering is significantly reduced by the application of a glycerol solution, which indicates an optical clearing effect due to osmotic dehydration and the matching of the refractive indices of scatterers in the epidermis.