Amplification Effect on Rayleigh Scattering and SBS in 25 km Distributed Fiber Raman Amplifier
Hua-Ping Gong; Zai-Xuan Zhang
2008-01-01
The amplification effect on stimulated Brillouin scattering (SBS) and Rayleigh scattering in the backward pumped G652 fibers Raman amplifier have been researched. The signal source is a tunable narrow spectral bandwidth (＜10 MHz) ECL laser and is pumped by the tunable power 1427.2 nm fiber Raman laser. The Rayleigh scattering lines are amplified by fiber Raman amplifier, and Stokes stimulated Brillouin scattering lines are amplified by fiber Raman amplifier and fiber BriUouin amplifier. The SBS lines total gain is a production of the gain of Raman and the gain of Brillouin amplifier. In experiment, the gain of SBS is about 42 dB and the saturation gain of 25 km G652 backward FRA is about 25 dB, so the gain of fiber Brillouin amplifier is about 17 dB.
Zaixuan Zhang; Huaping Gong
2009-01-01
The amplification effect on stimulated Brillouin scattering(SBS)and Rayleigh scattering in the backward pumped G652 fiber Raman amplifier(FRA)is studied.The pump source is a 1427.2-nm fiber Raman laser whose power is tunable between 0-1200 mW,and the signal source is a tunable narrow spectral bandwidth(＜10 MHz)external cavity laser(ECL).The Rayleigh scattering lines are amplified by the FRA and Stokes SBS lines are amplified by the FRA and the fiber Brillouin amplifier.The total gain of SBS lines is the production of the gain of Raman amplifier and that of Brillouin amplifier.In experiment,the SBS gain is about 42 dB and the saturation gain of 25-km G652 backward FRA is about 25 dB,so the gain of fiber Brillouin amplifier is about 17 dB.
Blue Skies, Coffee Creamer, and Rayleigh Scattering
Liebl, Michael
2010-01-01
The first physical explanation of Earths blue sky was fashioned in 1871 by Lord Rayleigh. Many discussions of Rayleigh scattering and approaches to studying it both in and out of the classroom are available. Rayleigh scattering accounts for the blue color of the sky and the orange/red color of the Sun near sunset and sunrise, and a number of…
Blue Skies, Coffee Creamer, and Rayleigh Scattering
Liebl, Michael
2010-01-01
The first physical explanation of Earths blue sky was fashioned in 1871 by Lord Rayleigh. Many discussions of Rayleigh scattering and approaches to studying it both in and out of the classroom are available. Rayleigh scattering accounts for the blue color of the sky and the orange/red color of the Sun near sunset and sunrise, and a number of…
Bétrémieux, Yan
2015-01-01
Detection of the signature of Rayleigh scattering in the transmission spectrum of an exoplanet is increasingly becoming the target of observational campaigns because the spectral slope of the Rayleigh continuum enables one to determine the scaleheight of its atmosphere in the absence of hazes. However, this is only true when one ignores the refractive effects of the exoplanet's atmosphere. I illustrate with a suite of simple isothermal clear Jovian H2-He atmosphere models with various abundances of water that refraction can decrease significantly the spectral slope of the Rayleigh continuum and that it becomes flat in the infrared. This mimics a surface, or an optically thick cloud deck, at much smaller pressures than one can probe in the non-refractive case. Although the relative impact of refraction on an exoplanet's transmission spectrum increases with decreasing atmospheric temperatures as well as increasing stellar temperature, it is still quite important from a retrieval's perspective even for a Jovian-...
Rayleigh scattering: blue sky thinking for future CMB observations
Lewis, Antony
2013-01-01
Rayleigh scattering from neutral hydrogen during and shortly after recombination causes the CMB anisotropies to be significantly frequency dependent at high frequencies. This may be detectable with Planck, and would be a strong signal at in any future space-based CMB missions. The later peak of the Rayleigh visibility compared to Thomson scattering gives an increased large-scale CMB polarization signal that is a greater than 4% effect for observed frequencies greater than 500GHz. There is a similar magnitude suppression on small scales from additional damping. Due to strong correlation between the Rayleigh and primary signal, measurement of the Rayleigh component is limited by noise and foregrounds, not cosmic variance of the primary CMB, and should observable over a wide range of angular scales at frequencies between roughly 200GHz and 800GHz. I give new numerical calculations of the temperature and polarization power spectra, and show that future CMB missions could measure the temperature Rayleigh cross-spe...
Shirinzadeh, B.; Hillard, M. E.; Blair, A. B.; Exton, R. J.
1991-01-01
Using a frequency-doubled Nd-YAG pulsed laser and a single-intensified CCD camera, Rayleigh scattering measurements have been performed to study the cluster formation in a Mach 6 wind tunnel at NASA Langley Research Center. These studies were conducted both in the free stream and in a model flow field for various flow conditions to gain an understanding of the dependence of the Rayleigh scattering (by clusters) on the local pressures and temperatures in the facility. Using the same laser system, simultaneous measurements of the local temperature have also been performed using the rotational Raman scattering of molecular nitrogen and determined the densities of molecular oxygen and nitrogen by using the vibrational Raman scattering from these species. Quantitative results are presented in detail with emphasis on the applicability of the Rayleigh scattering for obtaining quantitative measurements of molecular densities both in the free stream and in the model flow field.
In situ Characterization of Nanoparticles Using Rayleigh Scattering
Biswajit Santra; Shneider, Mikhail N; Roberto Car
2017-01-01
We report a theoretical analysis showing that Rayleigh scattering could be used to monitor the growth of nanoparticles under arc discharge conditions. We compute the Rayleigh scattering cross sections of the nanoparticles by combining light scattering theory for gas-particle mixtures with calculations of the dynamic electronic polarizability of the nanoparticles. We find that the resolution of the Rayleigh scattering probe is adequate to detect nanoparticles as small as C60 at the expected co...
Elm, Jonas; Norman, Patrick; Bilde, Merete;
2014-01-01
and hyperpolarizability β tensors. Using density functional theory, we elucidate the effect of cluster morphology on the scattering properties using a combinatorial sampling approach. We find that the Rayleigh scattering intensity depends quadratically on the number of water molecules in the cluster and that a single......The Rayleigh and hyper Rayleigh scattering properties of the binary (H 2SO4)(H2O)n and ternary (H 2SO4)(NH3)(H2O)n clusters are investigated using a quantum mechanical response theory approach. The molecular Rayleigh scattering intensities are expressed using the dipole polarizability α...
Modulational instability arising from collective Rayleigh scattering.
Robb, G R M; McNeil, B W J
2003-02-01
It is shown that under certain conditions a collection of dielectric Rayleigh particles suspended in a viscous medium and enclosed in a bidirectional ring cavity pumped by a strong laser field can produce a new modulational instability transverse to the wave-propagation direction. The source of the instability is collective Rayleigh scattering i.e., the spontaneous formation of periodic longitudinal particle-density modulations and a backscattered optical field. Using a linear stability analysis a dispersion relation is derived which determines the region of parameter space in which modulational instability of the backscattered field and the particle distribution occurs. In the linear regime the pump is modulationally stable. A numerical analysis is carried out to observe the dynamics of the interaction in the nonlinear regime. In the nonlinear regime the pump field also becomes modulationally unstable and strong pump depletion occurs.
The propagation dynamics of ultraviolet light filament with Rayleigh scattering in air
Zhang Hua
2005-01-01
In this paper we present for the first time the effects of Rayleigh scattering on the long distance propagation of ultraviolet (UV) light filament in air based on the stationary analysis. The simulation results show that the effects of Rayleigh scattering on the propagation of UV laser filaments may not be ignored. These influences are slightly dependent on the laser wavelength. We also compare the UV filament propagations at different input powers in the presence and the absence of the Rayleigh scattering and discuss the mechanisms of power loss and beam defocusing.In the absence of Rayleigh scattering, the filament propagation is determined by the oscillating behaviour of the beam size. In the presence of the scattering, the propagation lengths of filament are close to each other at different initial powers and determined by the Rayleigh scattering.
Optical switching by stimulated thermal Rayleigh scattering
Peterson, Lauren M.
1986-06-01
Preliminary experiments were conducted whose ultimate goal is to develop all-optical control functions useful in an all-optical or optical-electronic hybrid digital computer or for optical interconnects. Stimulated thermal Rayleigh scattering (STRS) based upon generator experiments was pursued for scattering angles of 90 deg and 180 deg (backscattering). A pulsed nitrogen laser pumped dye laser served as the radiation source and the interaction medium was a liquid to which an absorbing dye was added. STRS amplifier experiments were successful and gain was observed and studied parametrically using eosine dye in ethanol. The gain was found to increase (although the gain coefficient decreased) with increasing pump power and the gain was found to be a maximum at an absorption coefficient of about 2.6 per cm. The generator experiments did not lead to stimulated scattering due to the limited output power of the laser and its multi-longitudinal spectral mode content. These studies will be continued along with analytical modeling in order to characterize the interaction and to enable the optimization of the scattering process.
Polarized Rayleigh back-scattering from individual semiconductor nanowires
Zhang Duming; Wu Jian; Lu Qiujie; Gutierrez, Humberto R; Eklund, Peter C, E-mail: hur3@psu.edu [Department of Physics, Pennsylvania State University, University Park, PA 16802 (United States)
2010-08-06
A complete understanding of the interaction between electromagnetic radiation and semiconductor nanowires (NWs) is required in order to further develop a new generation of opto-electronic and photonic devices based on these nanosystems. The reduced dimensionality and high aspect ratio of nanofilaments can induce strong polarization dependence of the light absorption, emission and scattering, leading in some cases to the observation of optical antenna effects. In this work we present the first systematic study of polarized Rayleigh back-scattering from individual crystalline semiconductor NWs with known crystalline structure, orientation and diameters. To explain our experimental Rayleigh polar patterns, we propose a simple theory that relies on a secondary calculation of the volume-averaged internal electromagnetic fields inside the NW. These results revealed that the internal and emitted field can be enhanced depending on the polarization with respect to the NW axis; we also show that this effect strongly depends on the NW diameter.
Technical Report: Rayleigh Scattering Combustion Diagnostic
Adams, Wyatt [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Hecht, Ethan [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
2015-07-29
A laser Rayleigh scattering (LRS) temperature diagnostic was developed over 8 weeks with the goal of studying oxy-combustion of pulverized coal char in high temperature reaction environments with high concentrations of carbon dioxide. Algorithms were developed to analyze data collected from the optical diagnostic system and convert the information to temperature measurements. When completed, the diagnostic will allow for the kinetic gasification rates of the oxy-combustion reaction to be obtained, which was previously not possible since the high concentrations of high temperature CO_{2} consumed thermocouples that were used to measure flame temperatures inside the flow reactor where the combustion and gasification reactions occur. These kinetic rates are important for studying oxycombustion processes suitable for application as sustainable energy solutions.
Brown, Adrian J
2013-01-01
Scattering by particles significantly smaller than the wavelength is an important physical process in the rocky bodies in our solar system and beyond. A number of observations of spectral bluing (referred to in those papers as "Rayleigh scattering") on planetary surfaces have been recently reported, however, the necessary mathematical modeling of this phenomenon has not yet achieved maturity. This paper is a first step to this effect, by examining the effect of grain size and optical index on the albedo of small conservative and absorbing particles as a function of wavelength. The basic conditions necessary for spectral bluing or reddening to be observed in real-world situations are identified. We find that any sufficiently monomodal size distribution of scattering particles will cause spectral bluing in some part of the EM spectrum regardless of its optical index.
Rayleigh scattering in the atmospheres of hot stars
Fišák, Jakub; Munzar, Dominik; Kubát, Jiří
2016-01-01
Rayleigh scattering is a result of an interaction of photons with bound electrons. Rayleigh scattering is mostly neglected in calculations of hot star model atmospheres because most of the hydrogen atoms are ionized and the heavier elements have a lower abundance than hydrogen. In atmospheres of some chemically peculiar stars, helium overabundant regions containing singly ionized helium are present and Rayleigh scattering can be a significant opacity source. We evaluate the contribution of Rayleigh scattering by neutral hydrogen and singly ionized helium in the atmospheres of hot stars with solar composition and in the atmospheres of helium overabundant stars. We computed several series of model atmospheres using the TLUSTY code and emergent fluxes using the SYNSPEC code. These models describe atmospheres of main sequence B-type stars with different helium abundance. We used an existing grid of models for atmospheres with solar chemical composition and we calculated an additional grid for helium-rich stars wi...
Rayleigh scattering in the atmospheres of hot stars
Fišák, J.; Krtička, J.; Munzar, D.; Kubát, J.
2016-05-01
Context. Rayleigh scattering is a result of an interaction of photons with bound electrons. Rayleigh scattering is mostly neglected in calculations of hot star model atmospheres because most of the hydrogen atoms are ionized and the heavier elements have a lower abundance than hydrogen. In atmospheres of some chemically peculiar stars, helium overabundant regions containing singly ionized helium are present and Rayleigh scattering can be a significant opacity source. Aims: We evaluate the contribution of Rayleigh scattering by neutral hydrogen and singly ionized helium in the atmospheres of hot stars with solar composition and in the atmospheres of helium overabundant stars. Methods: We computed several series of model atmospheres using the TLUSTY code and emergent fluxes using the SYNSPEC code. These models describe atmospheres of main sequence B-type stars with different helium abundance. We used an existing grid of models for atmospheres with solar chemical composition and we calculated an additional grid for helium-rich stars with N(He)/N(H) = 10. Results: Rayleigh scattering by neutral hydrogen can be neglected in atmospheres of hot stars, while Rayleigh scattering by singly ionized helium can be a non-negligible opacity source in some hot stars, especially in helium-rich stars.
In situ Characterization of Nanoparticles Using Rayleigh Scattering
Santra, Biswajit; Shneider, Mikhail N.; Car, Roberto
2017-01-01
We report a theoretical analysis showing that Rayleigh scattering could be used to monitor the growth of nanoparticles under arc discharge conditions. We compute the Rayleigh scattering cross sections of the nanoparticles by combining light scattering theory for gas-particle mixtures with calculations of the dynamic electronic polarizability of the nanoparticles. We find that the resolution of the Rayleigh scattering probe is adequate to detect nanoparticles as small as C60 at the expected concentrations of synthesis conditions in the arc periphery. Larger asymmetric nanoparticles would yield brighter signals, making possible to follow the evolution of the growing nanoparticle population from the evolution of the scattered intensity. Observable spectral features include characteristic resonant behaviour, shape-dependent depolarization ratio, and mass-dependent line shape. Direct observation of nanoparticles in the early stages of growth with unobtrusive laser probes should give insight on the particle formation mechanisms and may lead to better-controlled synthesis protocols.
In situ Characterization of Nanoparticles Using Rayleigh Scattering.
Santra, Biswajit; Shneider, Mikhail N; Car, Roberto
2017-01-10
We report a theoretical analysis showing that Rayleigh scattering could be used to monitor the growth of nanoparticles under arc discharge conditions. We compute the Rayleigh scattering cross sections of the nanoparticles by combining light scattering theory for gas-particle mixtures with calculations of the dynamic electronic polarizability of the nanoparticles. We find that the resolution of the Rayleigh scattering probe is adequate to detect nanoparticles as small as C60 at the expected concentrations of synthesis conditions in the arc periphery. Larger asymmetric nanoparticles would yield brighter signals, making possible to follow the evolution of the growing nanoparticle population from the evolution of the scattered intensity. Observable spectral features include characteristic resonant behaviour, shape-dependent depolarization ratio, and mass-dependent line shape. Direct observation of nanoparticles in the early stages of growth with unobtrusive laser probes should give insight on the particle formation mechanisms and may lead to better-controlled synthesis protocols.
Gol' danskii, V.I.; Krupyanskii, Yu.F.; Fleurov, V.N.
1986-06-01
Specific features of the Rayleigh Scattering of Moessbauer Radiation (RSMR) technique in the study of biological systems are described. Experimental data show that the temperature and hydration degree are the principal parameters which influence intramolecular mobility in biopolymers. Data on temperature dependencies of elastic fraction, f, and spectrum line-shape do not fit neither Debye or Einstein models of solids nor the free diffusion in liquids and demand for their explanation a multimode approximation (i.e. a wide spectrum of correlation times, at T=293 K from 10/sup -6/s to 10/sup -12/-10/sup -13/s). On the basis of RSMR, low temperature specific heat and X-ray dynamic analysis data and from the general conditions that information macromolecule must be in a non-equilibrium state (an independent confirmation of this fact comes from the kinetic model of protein folding) a glass-like dynamical model of biopolymers is formulated. A possible interpretation of RSMR data shows that fluctuatively prepared tunneling between quasiequilibrium positions (QEP) can prevail activated transitions up to a room temperature.
Rayleigh scattering in few-mode optical fibers
Wang, Zhen; Wu, Hao; Hu, Xiaolong; Zhao, Ningbo; Mo, Qi; Li, Guifang
2016-01-01
The extremely low loss of silica fibers has enabled the telecommunication revolution, but single-mode fiber-optic communication systems have been driven to their capacity limits. As a means to overcome this capacity crunch, space-division multiplexing (SDM) using few-mode fibers (FMF) has been proposed and demonstrated. In single-mode optical fibers, Rayleigh scattering serves as the dominant mechanism for optical loss. However, to date, the role of Rayleigh scattering in FMFs remains elusive. Here we establish and experimentally validate a general model for Rayleigh scattering in FMFs. Rayleigh backscattering not only sets the intrinsic loss limit for FMFs but also provides the theoretical foundation for few-mode optical time-domain reflectometry, which can be used to probe perturbation-induced mode-coupling dynamics in FMFs. We also show that forward inter-modal Rayleigh scattering ultimately sets a fundamental limit on inter-modal-crosstalk for FMFs. Therefore, this work not only has implications specifically for SDM systems but also broadly for few-mode fiber optics and its applications in amplifiers, lasers, and sensors in which inter-modal crosstalk imposes a fundamental performance limitation. PMID:27775003
Rayleigh scattering in few-mode optical fibers
Wang, Zhen; Wu, Hao; Hu, Xiaolong; Zhao, Ningbo; Mo, Qi; Li, Guifang
2016-10-01
The extremely low loss of silica fibers has enabled the telecommunication revolution, but single-mode fiber-optic communication systems have been driven to their capacity limits. As a means to overcome this capacity crunch, space-division multiplexing (SDM) using few-mode fibers (FMF) has been proposed and demonstrated. In single-mode optical fibers, Rayleigh scattering serves as the dominant mechanism for optical loss. However, to date, the role of Rayleigh scattering in FMFs remains elusive. Here we establish and experimentally validate a general model for Rayleigh scattering in FMFs. Rayleigh backscattering not only sets the intrinsic loss limit for FMFs but also provides the theoretical foundation for few-mode optical time-domain reflectometry, which can be used to probe perturbation-induced mode-coupling dynamics in FMFs. We also show that forward inter-modal Rayleigh scattering ultimately sets a fundamental limit on inter-modal-crosstalk for FMFs. Therefore, this work not only has implications specifically for SDM systems but also broadly for few-mode fiber optics and its applications in amplifiers, lasers, and sensors in which inter-modal crosstalk imposes a fundamental performance limitation.
Yang, Jidong; Wang, Ernv; Zhou, Shang; Yang, Qiong
2015-03-01
Propranolol, a chiral drug with two configurations, i.e., (R)-propranolol hydrochloride (RPH) and (S)-propranolol hydrochloride (SPH), has racemes that can be used in clinical diagnosis due to their synergistic effects. SPH has a β-receptor blocking effect, and RPH has an antiarrhythmic effect. In pH 4.6 Britton-Robinson (BR) buffer solution, both RPH and SPH can react with erythrosine B to form 1:1 ion-association complexes. In the SPH-Ery B reaction system, a remarkable enhancement of the resonance Rayleigh scattering (RRS) signal located at 338 nm was observed. However, a similar phenomenon was not obvious and was unstable in the RPH-Ery B reaction system. Based on this result, a simple, novel and sensitive method for the determination of SPH was proposed based on the RRS technique. The linear range and limit of detection were 0.0680~4.0 µg mL(-1) and 20.6 ng mL(-1), respectively. Additionally, the spectroscopic approaches of frequency doubling scattering (FDS) and second-order scattering (SOS) were also proposed for SPH detection in this article. The interaction information regarding the mechanism of the reaction, suitable reaction conditions, influencing factors and the effects of mixed solutions were our investigation aims. The method had been applied to the determination of SPH in fresh serum and urine samples of healthy human subjects with satisfactory results.
Decoherence due to elastic rayleigh scattering
Uys, H
2010-11-01
Full Text Available in this manuscript now enables an accurate calculation of Rayleigh decoherence for these low-field trapped ion as well as other coherent-control experiments. We thank W.M. Itano, J. P. Britton, D. Hanneke, and M. J. Holland for useful suggestions.M. J. B.... acknowledges support from Georgia Tech and IARPA. D.M. is supported by NSF. This work was supported by the DARPA OLE program and by IARPA. This manuscript is the contribution of NIST and is not subject to U.S. copyright. *huys@csir.co.za †john...
A Rayleigh-Brillouin scattering spectrometer for ultraviolet wavelengths
Gu, Ziyu; van Duijn, Eric-Jan; Ubachs, Wim; 10.1063/1.4721272
2012-01-01
A spectrometer for the measurement of spontaneous Rayleigh-Brillouin scattering line profiles at ultraviolet wavelengths from gas phase molecules has been developed, employing a high-power frequency-stabilized UV laser with narrow bandwidth (2 MHz). The UV light from a frequency-doubled titanium:sapphire laser is further amplified in an enhancement cavity, delivering a 5 Watt UV-beam propagating through the interaction region inside a scattering cell. The design of the RB-scattering cell allows for measurements at gas pressures in the range 0-4 bar and at stably controlled temperatures from -30 to 70 degree Celsius. A scannable Fabry-Perot analyzer with instrument resolution of 232 MHz probes the Rayleigh-Brillouin profiles. Measurements on N2 and SF6 gases demonstrate the high signal-to-noise ratio achievable with the instrument, at the 1% level at the peak amplitude of the scattering profile.
Fast sampling model for X-ray Rayleigh scattering
Grichine, V M
2013-01-01
A simple model for X-ray Rayleigh scattering is discussed in terms of the process total cross-section and the angular distribution of scattered X-ray photons. Comparisons with other calculations and experimental data are presented. The model is optimized for the simulation of X-ray tracking inside experimental setups with complex geometry where performance and memory volume are issues to be optimized. (C) 2013 Elsevier B.V. All rights reserved.
Size Determination of Argon Clusters from a Rayleigh Scattering Experiment
LEI An-Le; ZHAI Hua-Jin; LIU Bing-Chen; LI Zhong; NI Guo-Yuan; XU Zhi-Zhan
2000-01-01
Argon clusters are produced in the process of adiabatic expansion of a high backing pressure gas into vacuum through a nozzle. The cluster size is determined by a Rayleigh scattering measurement. The scattered signal measured is proportional to the 2.78th power of gas stagnation pressure. The average cluster sizes vary from 100 to more than 12000 atoms/cluster with the argon gas backing pressures ranging between 3 to 45 atm.
Large-scale inhomogeneity in sapphire test masses revealed by Rayleigh scattering imaging
Yan, Zewu; Ju, Li; Eon, François; Gras, Slawomir; Zhao, Chunnong; Jacob, John; Blair, David G.
2004-03-01
Rayleigh scattering in test masses can introduce noise and reduce the sensitivity of laser interferometric gravitational wave detectors. In this paper, we present laser Rayleigh scattering imaging as a technique to investigate sapphire test masses. The system provides three-dimensional Rayleigh scattering mapping of entire test masses and quantitative evaluation of the Rayleigh scattering coefficient. Rayleigh scattering mapping of two sapphire samples reveals point defects as well as inhomogeneous structures in the samples. We present results showing significant non-uniform scattering within two 4.5 kg sapphire test masses manufactured by the heat exchanger method.
Rayleigh scattering of a spherical sound wave.
Godin, Oleg A
2013-02-01
Acoustic Green's functions for a homogeneous medium with an embedded spherical obstacle arise in analyses of scattering by objects on or near an interface, radiation by finite sources, sound attenuation in and scattering from clouds of suspended particles, etc. An exact solution of the problem of diffraction of a monochromatic spherical sound wave on a sphere is given by an infinite series involving products of Bessel functions and Legendre polynomials. In this paper, a simple, closed-form solution is obtained for scattering by a sphere with a radius that is small compared to the wavelength. Soft, hard, impedance, and fluid obstacles are considered. The solution is valid for arbitrary positions of the source and receiver relative to the scatterer. Low-frequency scattering is shown to be rather sensitive to boundary conditions on the surface of the obstacle. Low-frequency asymptotics of the scattered acoustic field are extended to transient incident waves. The asymptotic expansions admit an intuitive interpretation in terms of image sources and reduce to classical results in appropriate limiting cases.
Rayleigh-Brillouin Scattering in Binary Gas Mixtures
Gu, Ziyu; van de Water, Willem; Marques, Wilson
2015-01-01
Precise measurements are performed on spectral lineshapes of spontaneous Rayleigh-Brillouin scattering in mixtures of the noble gases Ar and Kr, with He. Admixture of a light He atomic fraction results in marked changes of the spectra, although in all experiments He is merely a spectator atom: it affects the relaxation of density fluctuations of the heavy constituent, but its contribution to the scattered light intensity is negligibly small. The results are compared to a theory for the spectral lineshape without adjustable parameters, yielding excellent agreement for the case of binary mono-atomic gases, signifying a step towards modeling and understanding of light scattering in more complex molecular media.
Rayleigh x-ray scattering from many-electron atoms and ions
Surzhykov, A.; Yerokhin, V. A.; Stöhlker, Th; Fritzsche, S.
2015-07-01
A theoretical analysis is presented for the elastic Rayleigh scattering of x-rays by many-electron atoms and ions. Special emphasis is placed on the angular distribution and linear polarization of the scattered photons for the case when the incident light is completely (linearly) polarized. Based on second-order perturbation theory and the independent particle approximation, we found that the Rayleigh angular distribution is strongly affected by the charge state and shell structure of the target ions or atoms. This effect can be observed experimentally at modern synchrotron facilities and might provide further insight into the structure of heavy atomic systems.
Yu, Sh.; Xiao, X.; Xu, G.
2016-11-01
In order to effectively eliminate Rayleigh and Raman scattering, a method based on Kriging interpolation is proposed, in which both the distance and the correlation between the scattering region and the nonscattering region are considered. The experimental results show that an unbiased estimation of the scattering region is achieved by this Kriging interpolation. Compared with other interpolation methods that use only the neighboring points, the performance of this method for eliminating the scattering region is much less sensitive to the scattering range that we set.
Rayleigh scattering and nonlinear inversion of elastic waves
Gritto, R.
1995-12-01
Rayleigh scattering of elastic waves by an inclusion is investigated and the limitations determined. In the near field of the inhomogeneity, the scattered waves are up to a factor of 300 stronger than in the far field, excluding the application of the far field Rayleigh approximation for this range. The investigation of the relative error as a function of parameter perturbation shows a range of applicability broader than previously assumed, with errors of 37% and 17% for perturbations of {minus}100% and +100%, respectively. The validity range for the Rayleigh limit is controlled by large inequalities, and therefore, the exact limit is determined as a function of various parameter configurations, resulting in surprisingly high values of up to k{sub p}R = 0.9. The nonlinear scattering problem can be solved by inverting for equivalent source terms (moments) of the scatterer, before the elastic parameters are determined. The nonlinear dependence between the moments and the elastic parameters reveals a strong asymmetry around the origin, which will produce different results for weak scattering approximations depending on the sign of the anomaly. Numerical modeling of cross hole situations shows that near field terms are important to yield correct estimates of the inhomogeneities in the vicinity of the receivers, while a few well positioned sources and receivers considerably increase the angular coverage, and thus the model resolution of the inversion parameters. The pattern of scattered energy by an inhomogeneity is complicated and varies depending on the object, the wavelength of the incident wave, and the elastic parameters involved. Therefore, it is necessary to investigate the direction of scattered amplitudes to determine the best survey geometry.
Suppression of Rayleigh-scattering-induced noise in OEOs.
Okusaga, Olukayode; Cahill, James P; Docherty, Andrew; Menyuk, Curtis R; Zhou, Weimin; Carter, Gary M
2013-09-23
Optoelectronic oscillators (OEOs) are hybrid RF-photonic devices that promise to be environmentally robust high-frequency RF sources with very low phase noise. Previously, we showed that Rayleigh-scattering-induced noise in optical fibers coupled with amplitude-to-phase noise conversion in photodetectors and amplifiers leads to fiber-length-dependent noise in OEOs. In this work, we report on two methods for the suppression of this fiber-length-dependent noise: altering the amplitude-dependent phase delay of the OEO loops and suppressing the Rayleigh-scattering-induced noise in optical fibers. We report a 20 dB reduction in the flicker phase noise of a 6 km OEO via these suppression techniques.
Malykin, G. B.
2016-04-01
At present, single-mode optical fibers composed of metamaterials—so-called "left-handed" optical media—for the far- and mid-IR ranges have already been created. In the near future, left-handed singlemode optical fibers for the visible and near-IR ranges will be created, light-carrying cores of which will be composed by an ordered structure of dielectric elements, the dimensions of which will be much smaller than the light wavelength, while the effective refractive index of the structure will be negative; i.e., the structure will possess the so-called "Veselago effect." We show that, because the dimensions of these dielectric elements many times exceed the dimensions of molecules of optical media, the elements should strongly scatter light, with this scattering considerably exceeding the Rayleigh (molecular) light scattering that occurs in conventional quartz single-mode optical fibers. We propose to term this phenomenon the quasi-Rayleigh light scattering. Numerical estimates of the quasi-Rayleigh light scattering for left-handed single-mode optical fibers at a light wavelength of λ = 1.55 μm have been made.
Rayleigh wave scattering at the foot of a mountain
P. S. Deshwal
1987-01-01
Full Text Available A theoretical study of scattering of seismic waves at the foot of a mountain is discussed here. A mountain of an arbitrary shape and of width a (0≤x≤a, z=0 in the surface of an elastic solid medium (z≥0 is hit by a Rayleigh wave. The method of solution is the technique of Wiener and Hopf. The reflected, transmitted and scattered waves are obtained by inversion of Fourier transforms. The scattered waves behave as decaying cylindrical waves at distant points and have a large amplitude near the foot of the mountain. The transmitted wave decreases exponentially as its distance from the other end of the mountain increases.
Two-dimensional temperature determination in sooting flames by filtered Rayleigh scattering
Hoffman, D.; Münch, K.-U.; Leipertz, A.
1996-04-01
We present what to our knowledge are the first filtered Rayleigh scattering temperature measurements and use them in sooting flame. This new technique for two-dimensional thermography in gas combustion overcomes some of the major disadvantages of the standard Rayleigh technique. It suppresses scattered background light from walls or windows and permits detection of two-dimensional Rayleigh intensity distributions of the gas phase in the presence of small particles by spectral filtering of the scattered light.
Benabid, F.; Notcutt, M.; Ju, L.; Blair, D. G.
1999-10-01
We present the level of noise induced by Rayleigh-scattered light from sapphire test mass, the limit of scattering loss on build-up power inside the interferometer and finally the tolerable absorption loss in order to meet the specification of the interferometer sensitivity. The results show that the Rayleigh scattering induced noise remains below h˜10 -25 Hz -1/2 and a higher tolerance on the absorption level in sapphire substrate compared with silica substrate.
Analytical evaluation of atomic form factors: application to Rayleigh scattering
Safari, L; Amaro, P; Jänkälä, K; Fratini, F
2014-01-01
Atomic form factors are widely used for the characterization of targets and specimens, from crystallography to biology. By using recent mathematical results, here we derive an analytical expression for the atomic form factor within the independent particle model constructed from nonrelativistic screened hydrogenic wavefunctions. The range of validity of this analytical expression is checked by comparing the analytically obtained form factors with the ones obtained within the Hartee-Fock method. As an example, we apply our analytical expression for the atomic form factor to evaluate the differential cross section for Rayleigh scattering off neutral atoms.
Instantaneous Rayleigh scattering from excitons localized in monolayer islands
Langbein, Wolfgang; Leosson, Kristjan; Jensen, Jacob Riis;
2000-01-01
We show that the initial dynamics of Rayleigh scattering from excitons in quantum wells can be either instantaneous or delayed, depending on the exciton ensemble studied. For excitation of the entire exciton resonance, a finite rise time given by the inverse inhomogeneous broadening: of the exciton...... resonance is observed. Instead, when exciting only a subsystem of the exciton resonance, in our case excitons localized in quantum well regions of a specific monolayer thickness, the rise has an instantaneous component. This is due to the spatial nonuniformity of the initially excited exciton polarization...
Ribosome formation from subunits studied by stopped-flow and Rayleigh light scattering.
Antoun, Ayman; Pavlov, Michael Y.; Tenson, Tanel; Ehrenberg M, M åNs
2004-01-01
Light scattering and standard stopped-flow techniques were used to monitor rapid association of ribosomal subunits during initiation of eubacterial protein synthesis. The effects of the initiation factors IF1, IF2, IF3 and buffer conditions on subunit association were studied along with the role of GTP in this process. The part of light scattering theory that is essential for kinetic measurements is high-lighted in the main text and a more general treatment of Rayleigh scattering from macromolecules is given in an appendix.
Ribosome formation from subunits studied by stopped-flow and Rayleigh light scattering
Antoun Ayman
2004-01-01
Full Text Available Light scattering and standard stopped-flow techniques were used to monitor rapid association of ribosomal subunits during initiation of eubacterial protein synthesis. The effects of the initiation factors IF1, IF2, IF3 and buffer conditions on subunit association were studied along with the role of GTP in this process. The part of light scattering theory that is essential for kinetic measurements is high-lighted in the main text and a more general treatment of Rayleigh scattering from macromolecules is given in an appendix.
DSMC simulation of Rayleigh-Brillouin scattering in binary mixtures
Bruno, Domenico; Frezzotti, Aldo; Ghiroldi, Gian Pietro
2016-11-01
Rayleigh-Brillouin scattering spectra (RBS) in dilute gas mixtures have been simulated by the Direct Simulation Monte Carlo method (DSMC). Different noble gas binary mixtures have been considered and the spectra have been simulated adopting the hard sphere collision model. It is suggested that DSMC simulations can be used in the interpretation of light scattering experiments in place of approximate kinetic models. Actually, the former have a firmer physical ground and can be readily extended to treat gas mixtures of arbitrary complexity. The results obtained confirm the capability of DSMC to predict experimental spectra and clears the way towards the simulation of polyatomic gas mixtures of interest for actual application (notably, air) where tractable kinetic model equations are still lacking.
Xi, Cunxian; Liu, Zhongfang; Kong, Ling; Hu, Xiaoli; Liu, Shaopu
2008-04-14
In pH 4.2-4.8 HAc-NaAc buffer solution, folic acid (FA) could react with uranium (VI) to form a 2:1 anionic chelate which further reacted with some basic triphenylmethane dyes (BTPMD) such as Ethyl Violet (EV), Methyl Violet (MV) and Crystal Violet (CV) to form 1:2 ion-association complexes. As a result, not only the absorption spectra were changed, but also the intensities of resonance Rayleigh scattering (RRS) were enhanced greatly and the new RRS spectra were observed. The maximum RRS wavelengths were located at 328 nm for EV system, 325 nm for MV system and 328 nm for CV system. The fading degree (DeltaA) and RRS intensities (DeltaI) of three systems were different. Under given conditions, the DeltaA and DeltaI were all directly proportional to the concentration of FA. The linear ranges and the detection limits of RRS methods were 0.0039-5.0 microg mL(-1) and 1.2 ng mL(-1) for EV system, 0.0073-4.0 microg mL(-1) and 2.2 ng mL(-1) for MV system, 0.014-3.5 microg mL(-1) and 4.7 ng mL(-1) for CV system. The RRS methods exhibited higher sensitivity, so they are more suitable for the determination of trace FA. The optimum conditions, the influencing factors and the effects of coexisting substances on the reaction were investigated. The method can be applied to the determination of FA in serum and urine samples with satisfactory results. The structure of the ternary ion-association complex and the reaction mechanism were discussed in this work.
A general purpose exact Rayleigh scattering look-up table for ocean color remote sensing
无
2006-01-01
The current exact Rayleigh scattering calculation of ocean color remote sensing uses the look-up table (LUT), which is usually created for a special remote sensor and cannot be applied to other sensors. For practical application, a general purpose Rayleigh scattering LUT which can be applied to all ocean color remote sensors is generated. An adding-doubling method to solve the vector radiative transfer equation in the plane-parallel atmosphere is deduced in detail. Compared with the exact Rayleigh scattering radiance derived from the MODIS exact Rayleigh scattering LUT, it is proved that the relative error of Rayleigh scattering calculation with the adding-doubling method is less than 0.25%, which meets the required accuracy of the atmospheric correction of ocean color remote sensing. Therefore,the adding-doubling method can be used to generate the exact Rayleigh scattering LUT for the ocean color remote sensors. Finally, the general purpose exact Rayleigh scattering LUT is generated using the adding-doubling method. On the basis of the general purpose LUT, the calculated Rayleigh scattering radiance is tested by comparing with the LUTs of MODIS, SeaWiFS and the other ocean color sensors, showing that the relative errors are all less than 0.5%, and this general purpose LUT can be applied to all ocean color remote sensors.
Remote-sensing gas measurements with coherent Rayleigh-Brillouin scattering
Gerakis, A.; Shneider, M. N.; Stratton, B. C.
2016-07-01
We measure the coherent Rayleigh-Brillouin scattering (CRBS) signal integral as a function of the recorded gas pressure in He, Co2, SF6, and air, and we confirm the already established quadratic dependence of the signal on the gas density. We propose the use of CRBS as an effective diagnostic for the remote measurement of gas' density (pressure) and temperature, as well as polarizability, for gases of known composition.
Coherent Rayleigh-Brillouin scattering as a flow diagnostic technique
Graul, J. S.; Lilly, T. C. [Department of Mechanical and Aerospace Engineering, University of Colorado Colorado Springs, 1420 Austin Bluffs Parkway, Colorado Springs, CO 80918 (United States)
2014-12-09
Broadband coherent Rayleigh-Brillouin scattering (CRBS) was used to measure translational gas temperatures for nitrogen at the ambient pressure of 0.8 atm using a purpose-built Fabry-Perot etalon spectrometer. Temperatures derived from the CRBS spectral analysis were compared with experimentally-measured temperatures, and were found to be, on average, within 2% of the experimentally-measured value. Axial flow velocities from a double jet at a pressure ratio of 0.38 were also measured by looking at the Doppler shift of the CRBS line shape. With recent developments in chirped laser technology and the capacity of CRBS to simultaneously provide thermodynamic and bulk flow information, the CRBS line shape acquisition and analysis technique presented here may allow for future time-resolved, characterization of aerospace flows.
Camacho, Jorge F.; Rodríguez, Rosalío F.
2017-02-01
The fluctuating hydrodynamic treatment developed in the previous article for a nematic liquid crystal under the influence of a thermal gradient α and a uniform gravity field g, is used to calculate its Rayleigh light scattering spectrum. We find that the dissipative thermal gradient force enhances the Rayleigh-line intensity which varies as k -4 with the fluctuations of the wave number k. The Rayleigh line consists of three central Lorentzians, two of which are determined by the visco-heat modes coupling the entropy and director fluctuations, which is a pure non-equilibrium effect. The third Lorentzian is due only to director fluctuations. We find that the former peaks contain the Rayleigh wings owing to the orientational fluctuations of the aniosotropic molecules. It is also shown that the obtained spectrum reduces to the known equilibrium spectrum of a nematic and to that of a simple fluid. For the particular case in which the decay rates are diffusive, we calculate and plot the amplitudes of non-equilibrium fluctuations of the dynamic structure factor as a function of | α|2/ k 4, and also, the intermediate function in the equilibrium and non-equilibrium states.
Resonance Rayleigh scattering for detection of proteins in HPLC.
Lu, Xin; Luo, Zhihui; Liu, Chengwei; Zhao, Shulin
2008-09-01
An HPLC-resonance Rayleigh scattering (RRS) (HPLC-RRS) detection system is described for separation and detection of proteins. This system is based on the modification of a commercial HPLC instrument involving the addition of a pump and a T-shaped interface, and a common fluorescence detector was used for detection. The detection principle is based on the change of RRS intensity of the ion-association complex formed from biebrich scarlet (BS) and protein. The RRS signal was detected at lambdaex=lambdaem=376 nm. The utility of the presented method was demonstrated by the separation and determination of four proteins involving cytochrome (Cyt-c), lysozyme (Lys), HSA, and gamma-globulin (gamma-Glo). An LOD of 0.2-1.0 microg/mL was reached and a linear range was found between peak area and concentration in the range of 0.20-3.0 microg/mL for Cyt-c, 0.25-2.5 microg/mL for Lys, 1.5-10 microg/mL for HSA, and 2.0-15 microg/mL for gamma-Glo, with linear regression coefficients all above 0.99. The method presented has been applied to determine HSA and gamma-Glo in human serum samples synchronously.
In Situ Characterization of Nanostructures Using Rayleigh Scattering
Santra, Biswajit; Shneider, Mikhail N.; Car, Roberto
Controlling selective growth of nanotubes has posed a considerable challenge over the last two decades. A crucial step to overcoming such hurdle is to gain detailed knowledge of the early stage of nanomaterial syntheses for which in situ measurements are required. Laser-based probes, such as Rayleigh scattering (RS), can potentially characterize the shape and size of nanoparticles in situ . The intensity of RS in a gas mixed with nanoparticles is proportional to the polarizabilities of the constituent particles, therefore, theoretical spectroscopy can complement such measurements. Here, we employed time-dependent density functional theory to compute the frequency-dependent polarizabilities of various nanostructures and predicted the corresponding RS intensity and depolarization. We found that with increasing length and asymmetry of the nanostructures the longitudinal polarizability exhibited characteristic resonances leading to measurable signatures in the RS intensity and depolarization. Also by considering gas-particle mixtures at estimated experimental conditions for nanoparticle synthesis on the periphery of an arch, we predict that in situ characterization of a few nanometer long particles with concentration as low as one particle per million is feasible using RS. This work was supported by U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.
Dynamical narrowing of the Rayleigh scattering ring from a semiconductor microcavity
Langbein, W.; Hvam, Jørn Märcher
2001-01-01
In resonant secondary emission of light (SE), scattering by static disorder leads to coherent resonant Rayleigh scattering (RRS), while the scattering with other quasi-particles (e.g. phonons) leads to an incoherent emission called photoluminescence (PL). For a bare quantum well (QW) the SE does ...
Dynamical narrowing of the Rayleigh scattering ring from a semiconductor microcavity
Langbein, W.; Hvam, Jørn Märcher
2001-01-01
In resonant secondary emission of light (SE), scattering by static disorder leads to coherent resonant Rayleigh scattering (RRS), while the scattering with other quasi-particles (e.g. phonons) leads to an incoherent emission called photoluminescence (PL). For a bare quantum well (QW) the SE does ...
Planar Rayleigh scattering results in helium-air mixing experiments in a Mach-6 wind tunnel
Shirinzadeh, B.; Hillard, M. E.; Balla, R. Jeffrey; Waitz, I. A.; Anders, J. B.; Exton, R. J.
1992-01-01
Planar Rayleigh scattering measurements with an argon—fluoride excimer laser are performed to investigate helium mixing into air at supersonic speeds. The capability of the Rayleigh scattering technique for flow visualization of a turbulent environment is demonstrated in a large-scale, Mach-6 facility. The detection limit obtained with the present setup indicates that planar, quantitative measurements of density can be made over a large cross-sectional area (5 cm × 10 cm) of the flow field in...
Setting up a Rayleigh Scattering Based Flow Measuring System in a Large Nozzle Testing Facility
Panda, Jayanta; Gomez, Carlos R.
2002-01-01
A molecular Rayleigh scattering based air density measurement system has been built in a large nozzle testing facility at NASA Glenn Research Center. The technique depends on the light scattering by gas molecules present in air; no artificial seeding is required. Light from a single mode, continuous wave laser was transmitted to the nozzle facility by optical fiber, and light scattered by gas molecules, at various points along the laser beam, is collected and measured by photon-counting electronics. By placing the laser beam and collection optics on synchronized traversing units, the point measurement technique is made effective for surveying density variation over a cross-section of the nozzle plume. Various difficulties associated with dust particles, stray light, high noise level and vibration are discussed. Finally, a limited amount of data from an underexpanded jet are presented and compared with expected variations to validate the technique.
Study of Rayleigh scattering for visualization of helium-air mixing at Mach 6
Shirinzadeh, B.; Balla, R. J.; Hillard, M. E.; Anders, J. B.; Exton, R. J.; Waitz, I. A.
1991-01-01
Using an ArF excimer laser, planar Rayleigh scattering measurements were performed to investigate helium mixing into air at supersonic speeds. These experiments were conducted in the Mach 6, high-Reynolds-number facility at NASA Langley Research Center. The capability of the Rayleigh scattering technique for flow visualization of a turbulent environment was demonstrated. The qualitative agreement between the averaged Rayleigh results and the reduced mean-mass-densities obtained from probe measurements substantiate that careful application of the technique, even in the presence of clusters, can give very useful results. It was also demonstrated that planar, quantitative measurements can be made in the absence of clusters.
Flanagan, Gene [North Carolina State Univ., Raleigh, NC (United States)
2016-02-17
Yttrium barium copper oxide (YBCO) coated conductors are known for their ability to operate in the superconducting state at relatively high temperatures, even above the boiling point of liquid nitrogen (77 K). When these same conductors are operated at lower temperatures, they are able to operate in much higher magnetic fields than traditional superconductors like NiTi or Nb_{3}Sn. Thus, YBCO superconducting magnets are one of the primary options for generating the high magnetic fields needed for future high energy physics devices. Due to slow quench propagation, quench detection remains one of the primary limitations to YBCO magnets. Fiber optic sensing, based upon Rayleigh scattering, has the potential for spatial resolution approaching the wavelength of light, or very fast temporal resolution at low spatial resolution, and a continuum of combinations in between. This project has studied, theoretically and experimentally, YBCO magnets and Rayleigh scattering quench detection systems to demonstrate feasibility of the systems for YBCO quench protection systems. Under this grant an experimentally validated 3D quench propagation model was used to accurately define the acceptable range of spatial and temporal resolutions for effective quench detection in YBCO magnets and to evaluate present-day and potentially improved YBCO conductors. The data volume and speed requirements for quench detection via Rayleigh scattering required the development of a high performance fiber optic based quench detection/data acquisition system and its integration with an existing voltage tap/thermo-couple based system. In this project, optical fibers are tightly co-wound into YBCO magnet coils, with the fiber on top of the conductor as turn-to-turn insulation. Local changes in the temperature or strain of the conductor are sensed by the optical fiber, which is in close thermal and mechanical contact with the conductor. Intrinsic imperfections in the fiber reflect Rayleigh
Diode Laser Velocity Measurements by Modulated Filtered Rayleigh Scattering
Mach, J. J.; Varghese, P. L.; Jagodzinski, J. J.
1999-01-01
The ability of solid-state lasers to be tuned in operating frequency at MHz rates by input current modulation, while maintaining a relatively narrow line-width, has made them useful for spectroscopic measurements. Their other advantages include low cost, reliability, durability, compact size, and modest power requirements, making them a good choice for a laser source in micro-gravity experiments in drop-towers and in flight. For their size, they are also very bright. In a filtered Rayleigh scattering (FRS) experiment, a diode laser can be used to scan across an atomic or molecular absorption line, generating large changes in transmission at the resonances for very small changes in frequency. The hyperfine structure components of atomic lines of alkali metal vapors are closely spaced and very strong, which makes such atomic filters excellent candidates for sensitive Doppler shift detection and therefore for high-resolution velocimetry. In the work we describe here we use a Rubidium vapor filter, and work with the strong D(sub 2) transitions at 780 nm that are conveniently accessed by near infrared diode lasers. The low power output of infrared laser diodes is their primary drawback relative to other laser systems commonly used for velocimetry. However, the capability to modulate the laser frequency rapidly and continuously helps mitigate this. Using modulation spectroscopy and a heterodyne detection scheme with a lock-in amplifier, one can extract sub-microvolt signals occurring at a specific frequency from a background that is orders of magnitude stronger. The diode laser modulation is simply achieved by adding a small current modulation to the laser bias current. It may also be swept repetitively in wavelength using an additional lower frequency current ramp.
Rayleigh-Brillouin scattering profiles of air at different temperatures and pressures
Gu, Ziyu; van de Water, Willem; Ubachs, Wim
2013-01-01
Rayleigh Brillouin (RB) scattering profiles for air have been recorded for the temperature range from 255 to 340 K and the pressure range from 640 to 3300 mbar, covering the conditions relevant for the Earth's atmosphere and for planned atmospheric light detection and ranging (LIDAR) missions. The measurements performed at a wavelength of 366.8 nm detect spontaneous RB scattering at a 90 degree scattering angle from a sensitive intracavity setup, delivering scattering profiles at a 1 percent rms noise level or better. The elusive transport coefficient, the bulk viscosity, is effectively derived by a comparing the measurements to the model, yielding an increased trend. The calculated (Tenti S6) line shapes are consistent with experimental data at the level of 2 percent, meeting the requirements for the future RB scattering LIDAR missions in the Earth's atmosphere. However, the systematic 2 percent deviation may imply that the model has a limit to describe the finest details of RB scattering in air. Finally, it...
Estimating the location of a tunnel using correlation and inversion of Rayleigh wave scattering
Kasililar, A.; Harmankaya, U.; Wapenaar, C.P.A.; Draganov, D.S.
2013-01-01
The investigation of near-surface scatterers, such as cavities, tunnels, abandoned mine shafts, and buried objects, is important to mitigate geohazards and environmental hazards. By inversion of travel times of cross-correlated scattered waves, due to the incident Rayleigh waves, we estimate the loc
TANG XiaoLing; LIU ZhongFang; LIU ShaoPu; HU XiaoLi
2007-01-01
In pH 4.5 Britton-Robinson (BR) buffer solution, erythrosin (ET) can react with diphenhydramine (DP) to form a 1:1 ion-association complex, which not only results in the change of the absorption spectra, but also results in the great enhancement of resonance Rayleigh scattering (RRS) and the quenching of fluorescence. Furthermore, a new RRS spectrum will appear, and the maximum RRS wavelength was located at about 580 nm.In this work, the spectral characteristics of the absorption, fluorescence and RRS, the optimum conditions of the reaction and the properties of an analytical chemistry were investigated. A sensitive, simple and new method for the determination of DP by using erythrosin as a probe has been developed. The detection limits for DP were 0.0020 μg/mL for RRS method, 0.088 μg/mL for absorption method and 0.094 μg/mL for fluorophotometry. There was a linear relationship between the absorbance, RRS and fluorescence intensities and the drug concentration in the range of 0.0067-2.0, 0.29-6.4 and 0.31-3.2 μg/mL, respectively. The effects of the interaction of diphenhydramine and erythrosin on the absorption, fluorescence and resonance Rayleigh scattering spectra were discussed. In light polarization experiment, the polarization of RRS at maximum wavelength was measured to be P = 0.9779, and it revealed that the RRS spectrum of DP-ET complex consists mostly of resonance scattering and few resonance fluorescence. In this study, enthalpy of formation and mean polarizability were calculated by AM1 quantum chemistry method. In addition, the reaction mechanism and the reasons for the enhancement of scattering spectra and the energy transfer between absorption, fluorescence and RRS were discussed.
In situ nanoparticle diagnostics by multi-wavelength Rayleigh-Mie scattering ellipsometry
Gebauer, G
2003-01-01
We present and discuss the method of multiple-wavelength Rayleigh-Mie scattering ellipsometry for the in situ analysis of nanoparticles. It is applied to the problem of nanoparticles suspended in low-pressure plasmas. We discuss experimental results demonstrating that the size distribution and the complex refractive index can be determined with high accuracy and present a study on the in situ analysis of etching of melamine-formaldehyde nanoparticles suspended in an oxygen plasma. It is also shown that particles with a shell structure (core plus mantle) can be analysed by Rayleigh-Mie scattering ellipsometry. Rayleigh-Mie scattering ellipsometry is also applicable to in situ analysis of nanoparticles under high gas pressures and in liquids.
Planar Rayleigh scattering results in helium-air mixing experiments in a Mach-6 wind tunnel
Shirinzadeh, B.; Hillard, M. E.; Balla, R. J.; Waitz, I. A.; Anders, J. B.; Exton, R. J.
1992-01-01
Planar Rayleigh scattering measurements with an argon-fluoride excimer laser are performed to investigate helium mixing into air at supersonic speeds. The capability of the Rayleigh scattering technique for flow visualization of a turbulent environment is demonstrated in a large-scale, Mach-6 facility. The detection limit obtained with the present setup indicates that planar, quantitative measurements of density can be made over a large cross-sectional area (5 cm x 10 cm) of the flow field in the absence of clusters.
Planar Rayleigh Scattering Results in Helium/Air Mixing Experiments in a Mach 6 Wind Tunnel
Shirinzadeh, B.; Balla, R. Jeffrey; Hillard, M. E.; Anders, J. B.; Exton, R. J.; Waitz, I. A.
1991-01-01
Planar Rayleigh scattering measurements using an ArF-excimer laser have been performed to investigate helium mixing into air at supersonic speeds. The capability of the Rayleigh scattering technique for flow visualization of a turbulent environment is demonstrated in a large-scale, Mach 6facility. The detection limit obtained with the present setup indicates that planar, quantitative measurements of density can be made over a large cross sectional area (5 cm by 10 cm) of the flow field in the absence of clusters.
DUAN Hui; LIU Zhong-Fang; LIU Shao-Pu; KONG Ling
2008-01-01
Heated in a boiling water bath, penicillin antibiotics such as amoxicillin, ampicillin, sodium cloxacillin, sodium carbenicillin and sodium benzylpenicillin could react with K3[Fe(CN)6] to form combined products in a dilute HCl medium.As a result, resonance Rayleigh scattering (RRS) intensity was enhanced greatly and new RRS spectra appeared.The maximum scattering wavelengths of the five combined products are all located at 330 nm.The scattered intensity increments (△I) of the combined products are directly proportional to the concentrations of the antibiotics in a certain range.The methods exhibit high sensitivity, and the detection limits for the five penicillin antibiotics are between 4.61 and 5.62 ng·mL-1.The spectral characteristics of RRS and the optimum reaction conditions were investigated.The mechanism of reaction and the reasons for the enhancement of resonance light scattering were discussed.The effects of coexisting substances have been examined, and the results indicated that the method had a good selectivity.It can be applied to the determination of penicillin antibiotics in capsule, tablet, human serum and urine samples.
Wang, Menghua
2016-05-30
To understand and assess the effect of the sensor spectral response function (SRF) on the accuracy of the top of the atmosphere (TOA) Rayleigh-scattering radiance computation, new TOA Rayleigh radiance lookup tables (LUTs) over global oceans and inland waters have been generated. The new Rayleigh LUTs include spectral coverage of 335-2555 nm, all possible solar-sensor geometries, and surface wind speeds of 0-30 m/s. Using the new Rayleigh LUTs, the sensor SRF effect on the accuracy of the TOA Rayleigh radiance computation has been evaluated for spectral bands of the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) satellite and the Joint Polar Satellite System (JPSS)-1, showing some important uncertainties for VIIRS-SNPP particularly for large solar- and/or sensor-zenith angles as well as for large Rayleigh optical thicknesses (i.e., short wavelengths) and bands with broad spectral bandwidths. To accurately account for the sensor SRF effect, a new correction algorithm has been developed for VIIRS spectral bands, which improves the TOA Rayleigh radiance accuracy to ~0.01% even for the large solar-zenith angles of 70°-80°, compared with the error of ~0.7% without applying the correction for the VIIRS-SNPP 410 nm band. The same methodology that accounts for the sensor SRF effect on the Rayleigh radiance computation can be used for other satellite sensors. In addition, with the new Rayleigh LUTs, the effect of surface atmospheric pressure variation on the TOA Rayleigh radiance computation can be calculated precisely, and no specific atmospheric pressure correction algorithm is needed. There are some other important applications and advantages to using the new Rayleigh LUTs for satellite remote sensing, including an efficient and accurate TOA Rayleigh radiance computation for hyperspectral satellite remote sensing, detector-based TOA Rayleigh radiance computation, Rayleigh radiance calculations for high altitude
Liu Yongchun; Xiao Yunfeng; Li Beibei; Jiang Xuefeng; Li Yan; Gong Qihuang [State Key Lab for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China)
2011-07-15
We study the Rayleigh scattering induced by a diamond nanocrystal in a whispering-gallery-microcavity-waveguide coupling system and find that it plays a significant role in the photon transportation. On the one hand, this study provides insight into future solid-state cavity quantum electrodynamics aimed at understanding strong-coupling physics. On the other hand, benefitting from this Rayleigh scattering, effects such as dipole-induced transparency and strong photon antibunching can occur simultaneously. As a potential application, this system can function as a high-efficiency photon turnstile. In contrast to B. Dayan et al. [Science 319, 1062 (2008)], the photon turnstiles proposed here are almost immune to the nanocrystal's azimuthal position.
Linking Rayleigh-Rice theory with near linear shift invariance in light scattering phenomena
Stover, John C.; Schroeder, Sven; Staats, Chris; Lopushenko, Vladimir; Church, Eugene
2016-09-01
Understanding topographic scatter has been the subject of many publications. For optically smooth surfaces that scatter only from roughness (and not from contamination, films or bulk defects) the Rayleigh-Rice relationship resulting from a rigorous electromagnetic treatment has been successfully used for over three decades and experimentally proven at wavelengths ranging from the X-Ray to the far infrared (even to radar waves). The "holy grail" of roughness-induced scatter would be a relationship that is not limited to just optically smooth surfaces, but could be used for any surface where the material optical constants and the surface power spectral density function (PSD) are known. Just input these quantities and calculate the BRDF associated with any source incident angle, wavelength and polarization. This is an extremely challenging problem, but that has not stopped a number of attempts. An intuitive requirement on such general relationships is that they must reduce to the simple Rayleigh-Rice formula for sufficiently smooth surfaces. Unfortunately that does not always happen. Because most optically smooth surfaces also scatter from non-topographic features, doubt creeps in about the accuracy of Rayleigh-Rice. This paper investigates these issues and explains some of the confusion generated in recent years. The authors believe there are measurement issues, scatter source issues and rough surface derivation issues, but that Rayleigh- Rice is accurate as formulated and should not be "corrected." Moreover, it will be shown that the empirically observed near shift invariance of surface scatter phenomena is a direct consequence of the Rayleigh-Rice theory.
Yan, Zewu; Zhao, Chunnong; Ju, Li; Gras, Slawomir; Baringa, Pablo; Blair, David G.
2005-01-01
This article describes an automatic Rayleigh scattering mapping system (ARSMS), which enables quantitative high-resolution three-dimensional mapping of inhomogeneities in optical materials. The ARSMS allows large high-grade test mass samples for gravitational wave detectors to be evaluated to ensure that an adequate low level of scattering is achieved. The ARSMS combines proprietary camera software with data analysis software and control software to achieve fully automatic operation with graphical user interfaces. This article presents the instrument concept and examples of the output. Device mapping in all degrees of freedom is shown to be better than 0.5mm, with scattering sensitivity better than 0.5ppm/cm. This system is able to scan and map the Rayleigh scattering of large samples in both of cylindrical and rectangular samples using cylindrical and Cartesian coordinates.
Superlinear growth of Rayleigh scattering-induced intensity noise in single-mode fibers.
Cahill, James P; Okusaga, Olukayode; Zhou, Weimin; Menyuk, Curtis R; Carter, Gary M
2015-03-09
Rayleigh scattering generates intensity noise close to an optical carrier that propagates in a single-mode optical fiber. This noise degrades the performance of optoelectronic oscillators and RF-photonic links. When using a broad linewidth laser, we previously found that the intensity noise power scales linearly with optical power and fiber length, which is consistent with guided entropy mode Rayleigh scattering (GEMRS), a third order nonlinear scattering process, in the spontaneous limit. In this work, we show that this behavior changes significantly with the use of a narrow linewidth laser. Using a narrow linewidth laser, we measured the bandwidth of the intensity noise plateau to be 10 kHz. We found that the scattered noise power scales superlinearly with fiber length up to lengths of 10 km in the frequency range of 500 Hz to 10 kHz, while it scales linearly in the frequency range of 10 Hz to 100 Hz. These results suggest that the Rayleigh-scattering-induced intensity noise cannot be explained by third-order nonlinear scattering in the spontaneous limit, as previously hypothesized.
Verreycken, T; Van Gessel, A F H; Pageau, A; Bruggeman, P, E-mail: p.j.bruggeman@tue.n [Eindhoven University of Technology, Department of Applied Physics, PO Box 513, 5600 MB Eindhoven (Netherlands)
2011-04-15
Rayleigh scattering is used to determine the gas temperature of an atmospheric pressure dc excited glow discharge in air with a water electrode. The obtained temperatures are compared with calculated rotational temperatures measured by optical emission spectroscopy of OH(A-X) and N{sub 2}(C-B). At a current of 15 mA a deviation is found between T{sub rot}(OH) and the gas temperature obtained from Rayleigh scattering of about 1000 K. The gas temperatures obtained from Rayleigh scattering, N{sub 2}(C) and OH(A) in the positive column are, respectively, 2600 {+-} 100 K, 2700 {+-} 150 K and 3600 {+-} 200 K. It is shown that the rotational temperature of N{sub 2}(C) is a reliable measurement of the gas temperature while this is not the case for OH(A). The results are explained in the context of quenching processes of the excited states. Spatially resolved gas temperatures in both longitudinal and radial directions are presented. The observed strong temperature gradients near the electrodes are checked to be consistent with the power dissipation and the heat transfer in the discharge. The effect of the polarity of the water electrode and filamentation on the measured temperatures is discussed.
Superlinear growth of Rayleigh scattering-induced intensity noise in single-mode fibers
Cahill, James P; Zhou, Weimin; Menyuk, Curtis R; Carter, Gary M
2015-01-01
Rayleigh scattering generates intensity noise close to an optical carrier that propagates in a single-mode optical fiber. This noise degrades the performance of optoelectronic oscillators and RF-photonic links. When using a broad linewidth laser, we previously found that the intensity noise power scales linearly with optical power and fiber length, which is consistent with guided entropy mode Rayleigh scattering (GEMRS), a third order nonlinear scattering process, in the spontaneous limit. In this work, we show that this behavior changes significantly with the use of a narrow linewidth laser. Using a narrow linewidth laser, we measured the bandwidth of the intensity noise plateau to be 10 kHz. We found that the scattered noise power scales superlinearly with fiber length up to lengths of 10 km in the frequency range of 500 Hz to 10 kHz, while it scales linearly in the frequency range of 10 Hz to 100 Hz. These results suggest that the Rayleigh-scattering-induced intensity noise cannot be explained by third-ord...
Rayleigh-Brillouin scattering in SF6 in the kinetic regime
Wang, Yuanqing; Yu, Yin; Liang, Kun; Marques, Wilson; van de Water, Willem; Ubachs, Wim
2017-02-01
Rayleigh-Brillouin spectral profiles are measured with a laser-based scatterometry setup for a 90° scattering angle at a high signal-to-noise ratio (r.m.s. noise below 0.15% w.r.t. peak intensity) in sulfur-hexafluoride gas for pressures in the range 0.2-5 bar and for a wavelength of λ = 403.0 nm. The high quality data are compared to a number of light scattering models in order to address the effects of rotational and vibrational relaxation. While the vibrational relaxation rate is so slow that vibration degrees of freedom remain frozen, rotations relax on time scales comparable to those of the density fluctuations. Therefore, the heat capacity, the thermal conductivity and the bulk viscosity are all frequency-dependent transport coefficients. This is relevant for the Tenti model that depends on the values chosen for these transport coefficients. This is not the case for the other two models considered: a kinetic model based on rough-sphere interactions, and a model based on fluctuating hydrodynamics. The deviations with the experiment are similar between the three different models, except for the hydrodynamic model at pressures p≲ 2bar . As all models are in line with the ideal gas law, we hypothesize the presence of real gas effects in the measured spectra.
RAYLEIGH SCATTERING IN THE ATMOSPHERE OF THE WARM EXO-NEPTUNE GJ 3470B
Dragomir, Diana [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive Suite 102, Goleta, CA 93117 (United States); Benneke, Björn [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Pearson, Kyle A. [Department of Physics and Astronomy, Northern Arizona University, Flagstaff, AZ 86001 (United States); Crossfield, Ian J. M.; Barman, Travis [Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Eastman, Jason [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Biddle, Lauren I., E-mail: diana@oddjob.uchicago.edu [Gemini Observatory, Northern Operations Center, 670 N. Aohoku Place, Hilo, HI 96720 (United States)
2015-12-01
GJ 3470b is a warm Neptune-size planet transiting an M dwarf star. Like the handful of other small exoplanets for which transmission spectroscopy has been obtained, GJ 3470b exhibits a flat spectrum in the near- and mid-infrared. Recently, a tentative detection of Rayleigh scattering in its atmosphere has been reported. This signal manifests itself as an observed increase of the planetary radius as a function of decreasing wavelength in the visible. We set out to verify this detection and observed several transits of this planet with the LCOGT network and the Kuiper telescope in four different bands (Sloan g, Sloan i, Harris B, and Harris V). Our analysis reveals a strong Rayleigh scattering slope, thus confirming previous results. This makes GJ 3470b the smallest known exoplanet with a detection of Rayleigh scattering. We find that the most plausible scenario is a hydrogen/helium-dominated atmosphere covered by clouds which obscure absorption features in the infrared and hazes which give rise to scattering in the visible. Our results demonstrate the feasibility of exoplanet atmospheric characterization from the ground, even with meter-class telescopes.
Rayleigh scattering and the internal coupling parameter for arbitrary particle shapes
Maughan, Justin B.; Chakrabarti, Amitabha; Sorensen, Christopher M.
2017-03-01
A general method for calculating the Rayleigh scattering by a particle of arbitrary shape is introduced. Although analytical solutions for Rayleigh scattering exist for spheres and ellipsoids, analytical solutions for more complicated shapes don't exist. We find that in general the Rayleigh differential cross section goes as k4V2| α (m) | 2 where k = 2 π / λ and λ is the wavelength, V is the volume of the particle and α (m) the average volume polarizability which is dependent on the shape and the complex index of refraction, m. We use existing computational techniques, the discrete dipole approximation (DDA) and the T-matrix method, to calculate the differential scattering cross section divided by k4 and plot it vs V2 to determine | α (m) | 2. Furthermore, we show that this leads to a general description of the internal coupling parameter ρarbitrary‧ = 2 πk V/A | α (m) | where A is the average projected area of the particle in the direction of incident light. It is shown that this general method makes significant changes in the analysis of scattering by particles of any size and shape.
Rayleigh Scattering in the Atmosphere of the Warm Exo-Neptune GJ 3470b
Dragomir, Diana; Pearson, Kyle A; Crossfield, Ian J M; Eastman, Jason; Barman, Travis; Biddle, Lauren I
2015-01-01
GJ 3470b is a warm Neptune-size planet transiting a M dwarf star. Like the handful of other small exoplanets for which transmission spectroscopy has been obtained, GJ 3470b exhibits a flat spectrum in the near- and mid-infrared. Recently, a tentative detection of Rayleigh scattering in its atmosphere has been reported. This signal manifests itself as an observed increase of the planetary radius as a function of decreasing wavelength in the visible. We set out to verify this detection and observed several transits of this planet with the LCOGT network and the Kuiper telescope in four different bands (Sloan g', Sloan i', Harris B and Harris V). Our analysis reveals a strong Rayleigh scattering slope, thus confirming previous results. This makes GJ 3470b the smallest known exoplanet with a detection of Rayleigh scattering. We find that the most plausible scenario is a hydrogen/helium-dominated atmosphere covered by clouds which obscure absorption features in the infrared and hazes which give rise to scattering i...
Bandoro, J.; Sica, R. J.; Argall, S.
2012-12-01
An important aspect of solar terrestrial relations is the coupling between the lower and upper atmosphere-ionosphere system. The coupling is evident in the general circulation of the atmosphere, where waves generate in the lower atmosphere play an important role in the dynamics of the upper atmosphere, which feeds back on the lower atmosphere's circulation. To address coupling problems requires measurements over the broadest range of heights possible. A recently developed retrieval method for temperature profiles from Rayleigh-scatter lidar measurements using an inversion approach allows the upward extension of the altitude range of temperature by 10 to 15 km over the conventional method, thus producing the equivalent of increasing the systems power-aperture product by 4 times [1]. The method requires no changes to the lidar's hardware and thus, can be applied to the body of existing measurements. In addition, since the uncertainties of the retrieved temperature profile are found by a Monte Carlo error analysis, it is possible to isolate systematic and random uncertainties to model the effect of each one on the final uncertainty product for the temperature profile. This unambiguous separation of uncertainties was not previously possible as only the propagation of the statistical uncertainties are typically reported. For the Purple Crow Lidar, corrections for saturation (e.g. non-linearity) in the photocount returns, ozone extinction and background removal all contribute to the overall systematic uncertainty. Results of individually varying each systematic correction and the effect on the final temperature uncertainty through Monte Carlo realizations are presented to determine the importance for each one. For example, it was found that treatment of the background correction as a systematic versus statistical uncertainty gave results in agreement with each other. This new method is then applied to measurements obtained by the Purple Crow lidar' Rayleigh-scatter
Grace, Emily; Butcher, Alistair; Monroe, Jocelyn; Nikkel, James A.
2017-09-01
Large liquid argon detectors have become widely used in low rate experiments, including dark matter and neutrino research. However, the optical properties of liquid argon are not well understood at the large scales relevant for current and near-future detectors. The index of refraction of liquid argon at the scintillation wavelength has not been measured, and current Rayleigh scattering length calculations disagree with measurements. Furthermore, the Rayleigh scattering length and index of refraction of solid argon and solid xenon at their scintillation wavelengths have not been previously measured or calculated. We introduce a new calculation using existing data in liquid and solid argon and xenon to extrapolate the optical properties at the scintillation wavelengths using the Sellmeier dispersion relationship.
Rayleigh scattering in an optical nanofiber as a probe of higher-order mode propagation
Hoffman, Jonathan E; Beadie, Guy; Rolston, Steven L; Orozco, Luis A
2015-01-01
Optical nanofibers provide a rich platform for exploring atomic and optical phenomena even when they support only a single spatial mode. Nanofibers supporting higher-order modes provide additional degrees of freedom to enable complex evanescent field profiles for interaction with the surrounding medium, but local control of these profiles requires nondestructive evaluation of the propagating fields. Here, we use Rayleigh scattering for rapid measurement of the propagation of light in few-mode optical nanofibers. Imaging the Rayleigh scattered light provides direct visualization of the spatial evolution of propagating fields throughout the entire fiber, including the transition from core-cladding guidance to cladding-air guidance. We resolve the interference between higher-order modes to determine local beat lengths and modal content along the fiber, and show that the modal superposition in the waist can be systematically controlled by adjusting the input superposition. With this diagnostic we can measure vari...
Grace, Emily
2015-01-01
Like all the noble elements, argon and xenon are scintillators, \\emph{i.e.} they produce light when exposed to radiation. Large liquid argon detectors have become widely used in low background experiments, including dark matter and neutrino research. However, the index of refraction of liquid argon at the scintillation wavelength has not been measured and current Rayleigh scattering length calculations disagree with measurements. Furthermore, the Rayleigh scattering length and index of refraction of solid argon and solid xenon at their scintillation wavelengths have not been previously measured or calculated. We introduce a new calculation using previously measured data in liquid and solid argon and xenon to extrapolate the optical properties at the scintillation wavelengths using the Sellmeier dispersion relationship. As a point of validation, we compare our extrapolated index of refraction for liquid xenon against the measured value and find agreement within the uncertainties. This method results in a Rayle...
Resonant Rayleigh scattering of exciton-polaritons in multiple quantum wells
Malpuech, Guillaume; Kavokin, Alexey; Langbein, Wolfgang Werner;
2000-01-01
A theoretical concept of resonant Rayleigh scattering (RRS) of exciton-polaritons in multiple quantum wells (QWs) is presented. The optical coupling between excitons in different QWs can strongly affect the RRS dynamics, giving rise to characteristic temporal oscillations on a picosecond scale....... Bragg and anti-Bragg arranged QW structures with the same excitonic parameters are predicted to have drastically different RRS spectra. Experimental data on the RRS from multiple QWs show the predicted strong temporal oscillations at small scattering angles, which are well explained by the presented...
Rudakov, Fedor M [ORNL; Zhang, Zhili [ORNL
2012-01-01
We present a technique for nonintrusive and standoff detection of large organic molecules using coherent microwave Rayleigh scattering from plasma produced by structure sensitive photoionization through Rydberg states. We test the method on 1,4-diazobicyclooctane. Transitions between the 3s Rydberg state and higher lying Rydberg states are probed using two-color photoionization with 266?nm photons and photons in the range of 460-2400 nm. Photoionization is detected using microwave radiation, which is scattered by the unbounded electrons. Highly resolved Rydberg spectra are acquired in vacuum and in air.
Rayleigh scattering of two x-ray photons by an atom
Hopersky, Alexey N.; Nadolinsky, Alexey M.; Novikov, Sergey A.
2016-05-01
The process of elastic (Rayleigh) scattering of two x-ray free-electron laser (XFEL) photons by a free He atom is theoretically investigated. We obtain the absolute values and the forms of the triple differential scattering cross section. The main theoretical result is the highest probability of creation of scattered photons with energy ℏ ω±≅ℏ ω ±I1 s (ℏ ω is the energy of the incident XFEL photon, I1 s is the energy of the ionization threshold of the 1 s2 atomic shell). The probability of creation cooled (ω+ ) photons is smaller by many orders of magnitude, and is identically zero when the formal (nonphysical) energy of one of the scattered photons is 2 ℏ ω .
Zhang, Weiai; Ma, Caijuan; Su, Zhengquan; Bai, Yan
2016-11-01
This paper describes a highly sensitive and accurate approach using aniline blue (AB) (water soluble) as a probe to determine chitosan (CTS) through Resonance Rayleigh scattering (RRS). Under optimum experimental conditions, the intensities of RRS were linearly proportional to the concentration of CTS in the range from 0.01 to 3.5 μg/mL, and the limit of detection (LOD) was 6.94 ng/mL. Therefore, a new and highly sensitive method based on RRS for the determination of CTS has been developed. Furthermore, the effect of molecular weight of CTS and the effect of the degree of deacetylation of CTS on the accurate quantification of CTS was studied. The experimental data was analyzed by linear regression analysis, which indicated that the molecular weight and the degree of deacetylation of CTS had no statistical significance and this method could be used to determine CTS accurately. Meanwhile, this assay was applied for CTS determination in health products with satisfactory results.
A systematic study of Rayleigh-Brillouin scattering in air, N2 and O2 gases
Gu, Ziyu
2014-01-01
Spontaneous Rayleigh-Brillouin scattering experiments in air, N2 and O2 have been performed for a wide range of temperatures and pressures at a wavelength of 403 nm and at a 90 degrees scattering angle. Measurements of the Rayleigh-Brillouin spectral scattering profile were conducted at high signal-to-noise ratio for all three species, yielding high-quality spectra unambiguously showing the small differences between scattering in air, and its constituents N2 and O2. Comparison of the experimental spectra with calculations using the Tenti S6 model, developed in 1970s based on linearized kinetic equations for molecular gases, demonstrates that this model is valid to high accuracy. After previous measurements performed at 366 nm, the Tenti S6 model is here verified for a second wavelength of 403 nm. Values for the bulk viscosity for the gases are derived by optimizing the model to the measurements. It is verified that the bulk viscosity parameters obtained from previous experiments at 366 nm, are valid for wavel...
Rayleigh scattering in the transmission spectrum of HAT-P-18b
Kirk, J; Louden, T; Doyle, A P; Skillen, I; McCormac, J; Irwin, P G J; Karjalainen, R
2016-01-01
We have performed low-resolution ground-based transmission spectroscopy of the hot Jupiter HAT-P-18b using the ACAM instrument on the William Herschel Telescope (WHT). We detect a bluewards slope extending across our optical transmission spectrum which runs from 4750 Ang to 9250 Ang. The slope is consistent with Rayleigh scattering at the equilibrium temperature of the planet. We do not detect enhanced sodium absorption, which indicates a high altitude haze is masking the feature and giving rise to the Rayleigh slope. Our detection of an opacity source within a hot Jupiter atmosphere demonstrates that ground-based observations can provide transmission spectra with precision comparable to the Hubble Space Telescope (HST).
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.
Polarization of Rayleigh scattered Lyα in active galactic nuclei
Chang, Seok-Jun; Lee, Hee-Won; Yang, Yujin
2017-02-01
The unification scheme of active galactic nuclei invokes an optically thick molecular torus component hiding the broad emission line region. Assuming the presence of a thick neutral component in the molecular torus characterized by a H I column density >1022 cm-2, we propose that far-UV radiation around Lyα can be significantly polarized through Rayleigh scattering. Adopting a Monte Carlo technique, we compute polarization of Rayleigh scattered radiation near Lyα in a thick neutral region in the shape of a slab and a cylindrical shell. It is found that radiation near Lyα Rayleigh reflected from a very thick slab can be significantly polarized in a fairly large range of wavelength Δλ ˜ 50 Å exhibiting a flux profile similar to the incident one. Rayleigh transmitted radiation in a slab is characterized by the central dip with a complicated polarization behaviour. The optically thick part near Lyα centre is polarized in the direction perpendicular to the slab normal, which is in contrast to weakly polarized wing parts in the direction parallel to the slab normal. A similar polarization flip phenomenon is also found in the case of a tall cylindrical shell, in which the spatial diffusion along the vertical direction near the inner cylinder wall for core photons leads to a tendency of the electric field aligned to the direction perpendicular to the vertical axis. Observational implications are briefly discussed including spectropolarimetry of the quasar PG 1630+377 by Koratkar et al. in 1990 where Lyα is strongly polarized with no other emission lines polarized.
YI,Ao-Er; LIU,Zhong-Fang; LIU,Shao-Pu; KONG,Ling
2008-01-01
In pH 5.0-5.4 HOAc-NaOAc buffer solution, clindamycin (Clin) could react with Pd(II) to form a 1 : 1 cati-onic chelate, which could further react with halofluorescein dyes such as diiodofluorescein (DIP), erythrosine (Ery) and eosin Y (EY) to form 1:1 ion-association complexes. As a result, not only the absorption and fluorescence spectra were changed, but also the resonance Rayleigh scattering (RRS) intensities enhanced greatly and new RRS spectra appeared. The three reaction products had characteristic RRS spectra and their maximum RRS wavelengths were located at 285 (DIP system), 287 (Ery system) and 321 (EY system) nm, respectively. The scattering intensities were proportional to the concentration of Clin in certain range which could be applied to determine Clin. The linear ranges and detection limits of Clin were 0.025-2.1μg·mL-1 and 7.8 ng·mL-1 for the DIP system, 0.053-2.4μg·mL-1 and 16.0 ng·mL-1 for the Ery system, 0.038-2.4μg·mL-1 and 11.0 ng·mL-1 for the EY system, respectively. In this work, the optimum reaction conditions and the foreign substances were investigated. A simple, sensitive and fast method was developed for the determination of Clin either in the pharmaceutical form or in the human body fluid. Moreover, the composition, structure, reaction mechanism of the ternary complexes and their effects on the absorption, fluorescence and RRS spectra as well as the reasons of RRS enhancement were discussed.
Li, Ai Ping; Peng, Huanjun; Peng, Jing Dong; Zhou, Ming Qiong; Zhang, Jing
2015-08-01
Herein, a Rayleigh light-scattering (RLS) detection method combined with high performance liquid chromatograph (HPLC) without any post-column probe was developed for the separation and determination of three α1-adrenoceptor antagonists. The quantitative analysis is benefiting from RLS signal enhancement upon addition of methanol which induced molecular aggregation to form an hydrophobic interface between aggregates and water that produce a sort of superficial enhanced scattering effect. A good chromatographic separation among the compounds was achieved using a Gemini 5u C18 reversed phase column (250 mm × 4.6 mm; 4 μm) with a mobile phase consisting of methanol and ammonium acetate-formic acid buffer solution (25 mM; pH = 3.0) at the flow rate of 0.7 mL min-1. The RLS signal was monitored at λex = λem = 354 nm. A limit of detection (LOD) of 0.065-0.70 μg L-1 was reached and a linear range was found between peak height and concentration in the range of 0.75-15 μg L-1 for doxazosin mesylate (DOX), 0.075-3.0 μg L-1 for prazosin hydrochloride (PRH), and 0.25-5 μg L-1 for terazosin hydrochloride (TEH), with linear regression coefficients all above 0.999. Recoveries from spiked urine samples were 88.4-99.0% which is within acceptable limits. The proposed method is convenient, reliable and sensitive which has been used successfully in human urine samples.
Distinct Rayleigh scattering from hot spot mutant p53 proteins reveals cancer cells.
Jun, Ho Joon; Nguyen, Anh H; Kim, Yeul Hong; Park, Kyong Hwa; Kim, Doyoun; Kim, Kyeong Kyu; Sim, Sang Jun
2014-07-23
The scattering of light redirects and resonances when an electromagnetic wave interacts with electrons orbits in the hot spot core protein and oscillated electron of the gold nanoparticles (AuNP). This report demonstrates convincingly that resonant Rayleigh scattering generated from hot spot mutant p53 proteins is correspondence to cancer cells. Hot spot mutants have unique local electron density changes that affect specificity of DNA binding affinity compared with wild types. Rayleigh scattering changes introduced by hot-spot mutations were monitored by localized surface plasmon resonance (LSPR) shift changes. The LSPR λmax shift for hot-spot mutants ranged from 1.7 to 4.2 nm for mouse samples and from 0.64 nm to 2.66 nm for human samples, compared to 9.6 nm and 15 nm for wild type and mouse and human proteins, respectively with a detection sensitivity of p53 concentration at 17.9 nM. It is interesting that hot-spot mutants, which affect only interaction with DNA, launches affinitive changes as considerable as wild types. These changes propose that hot-spot mutants p53 proteins can be easily detected by local electron density alterations that disturbs the specificity of DNA binding of p53 core domain on the surface of the DNA probed-nanoplasmonic sensor.
Molecular Rayleigh Scattering Diagnostic for Dynamic Temperature, Velocity, and Density Measurements
Mielke, Amy R.; Elam, Kristie A.; Sung, Chi-Jen
2006-01-01
A molecular Rayleigh scattering technique is developed to measure dynamic gas temperature, velocity, and density in unseeded turbulent flows at sampling rates up to 16 kHz. A high power CW laser beam is focused at a point in an air jet plume and Rayleigh scattered light is collected and spectrally resolved. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. The circular interference fringe pattern is divided into four concentric regions and sampled at 1 and 16 kHz using photon counting electronics. Monitoring the relative change in intensity within each region allows for measurement of gas temperature and velocity. Independently monitoring the total scattered light intensity provides a measure of gas density. A low speed heated jet is used to validate the measurement of temperature fluctuations and an acoustically excited nozzle flow is studied to validate velocity fluctuation measurements. Power spectral density calculations of the property fluctuations, as well as mean and fluctuating quantities are presented. Temperature fluctuation results are compared with constant current anemometry measurements and velocity fluctuation results are compared with constant temperature anemometry measurements at the same locations.
Sudipta G Dastidar; P Bharath; Arindam Roy
2011-04-01
In this article we report experimental and theoretical results of angle-dependent laser light scattering of nano titanium dioxide nucleated on silica particles. It was observed that the experimental scattering profile from nano-titania coated silica (TCS) particle resembles that of a Rayleigh scattering. It can be inferred from the light scattering profile that nucleating fine particles onto a surface of a bigger particle (core), the resulting scattering profile is dominated by the smaller particles. Thin film transmittance measurement of TCS particles also supports this claim. The theoretical scattering predictions do not match with the experimental findings and the reasons for the discrepancies are addressed. This Rayleigh-like scattering property of TCS particles can be used in cosmetic formulations as a replacement for nanoparticles to provide protection from harmful ultraviolet rays. This study helps to provide insights into these systems for their potential usage in cosmetics.
Initial stage of cavitation in liquids and its observation by Rayleigh scattering
Pekker, M
2016-01-01
A theory is developed for the initial stage of cavitation in the framework of Zel'dovich-Fisher theory of nucleation in the field of negative pressure, while taking into account the surface tension dependence on the nanopore radius. A saturation mechanism is proposed that limits the exponential dependence of the nucleation rate on the energy required to create nanopores. An estimate of the saturated density of nanopores at the nucleation stage is obtained. It is shown that Rayleigh scattering can detect nanopores arising at the initial stage of cavitation development.
Antoniassi, Marcelo; Conceicao, Andre Luiz Coelho; Poletti, Martin Eduardo [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Dept. de Fisica e Matematica
2009-07-01
In this work we have been measured the intensity of Rayleigh and Compton scattering from normal (adipose and fibrous) and neoplastic (benign and malignant) breast tissues using a monoenergetic beam of 17,44keV and a Si(Li) detector positioned at 90 degrees of the direction of incidence. From the scattering peaks were obtained parameters like area, full width at half maximum (FWHM) and combined like the Rayleigh to Compton area ratio (R/C). The results showed that the FWHM and the R/C ratio are different for each tissue type. In this way, the obtained results suggest that it is possible to use this information to characterize and to differentiate the breast tissues, pointing the possibility of its use as complementary tool to the breast cancer diagnosis. (author)
SONG Yan-qi; LIU Shao-pu; LIU Zhong-fang; HU Xiao-li
2011-01-01
In 0.1 mol/L HCl medium,12-tungstophosphoric(TP) acid reacted with matrine(Mat) and oxymatrine(Oxy)to form an ion-association complex.As a result,the new spectra of resonance Rayleigh scattering(RRS),second-order scattering(SOS) and frequency doubling scattering(FDS) appeared and their intensities were enhanced greatly.The maximum scattering wavelengths of RRS,SOS and FDS were located at 370,670 and 390 nm,respectively.The increments of scattering intensity were directly proportional to the concentration of Mat and Oxy in a certain range.Based on this,the method for the determination of matrine and oxymatrine has been established.It has been applied to the determination of matrine and oxymatrine in samples of Radix sophorae flavescentis with satisfactory result.The reaction mechanism and reasons of RRS enhancement were discussed.
Otugen, M. Volkan
1997-01-01
Non-intrusive techniques for the dynamic measurement of gas flow properties such as density, temperature and velocity, are needed in the research leading to the development of new generation high-speed aircraft. Accurate velocity, temperature and density data obtained in ground testing and in-flight measurements can help understand the flow physics leading to transition and turbulence in supersonic, high-altitude flight. Such non-intrusive measurement techniques can also be used to study combustion processes of hydrocarbon fuels in aircraft engines. Reliable, time and space resolved temperature measurements in various combustor configurations can lead to a better understanding of high temperature chemical reaction dynamics thus leading to improved modeling and better prediction of such flows. In view of this, a research program was initiated at Polytechnic University's Aerodynamics Laboratory with support from NASA Lewis Research Center through grants NAG3-1301 and NAG3-1690. The overall objective of this program has been to develop laser-based, non-contact, space- and time-resolved temperature and velocity measurement techniques. In the initial phase of the program a ND:YAG laser-based dual-line Rayleigh scattering technique was developed and tested for the accurate measurement of gas temperature in the presence of background laser glare. Effort was next directed towards the development of a filtered, spectrally-resolved Rayleigh/Mie scattering technique with the objective of developing an interferometric method for time-frozen velocity measurements in high-speed flows utilizing the uv line of an ND:YAG laser and an appropriate molecular absorption filter. This effort included both a search for an appropriate filter material for the 266 nm laser line and the development and testing of several image processing techniques for the fast processing of Fabry-Perot images for velocity and temperature information. Finally, work was also carried out for the development of
Lian Hui Chen; Yi Jian; Hong Qun Luo; Shao Pu Liu; Xiao Li Hu
2007-01-01
In an acetic acid-sodium acetate buffer solution of pH 3.6-6.8, a compound complex was formed between sodium hyaluronate (abbreviated as SH) and some basic bisphenylnaphthylmethane dyes, leading to a great enhancement of the intensity of resonance Rayleigh scattering (RRS) and giving a new RRS spectrum, with its maximum scattering peak near 280 nm. It was also found that the intensity of RRS was directly proportional to the concentration of SH near the range between 0 and 3.0 mg/L. Based on these facts, a sensitive method for the determination of SH has been established. The method had good selectivity, and has been used for the determination of total amounts of SH in samples with satisfactory results. For the NB-SH system, the detection limit of SH was down to 13.7 ng/mL.
Binding equilibrium of I~- to serum albumin with resonance Rayleigh scattering
梁宏; 沈星灿; 蒋治良; 何锡文; 申泮文
2000-01-01
The binding equilibrium between l- and human serum albumin (HSA) or bovine serum albumin (BSA) has been studied by means of the resonance Rayleigh scattering (RRS) and equilibrium dialysis. It has been found for the first time that RRS and multiple frequency scattering (MFS) are enhanced as the l- binding to the HSA and BSA, but fluorescence quenches. The equilibrium dialysis results suggest that the binding of l- to HSA and BSA fits a phase-distribution model other than Scsitchard model, and that the order of magnitude of its phase-distribution constant was found to be 104. It is most probable that Cl~ or other anion ions influence the binding of P by changing the ionic strength in the solution. The dialysis at different pH indicates that the binding mechanism is due to the electrostatic forces between the T-and protonated basic amino-acid residues.
Metzler, Adam M; Siegmann, William L; Collins, Michael D
2012-02-01
The parabolic equation method with a single-scattering correction allows for accurate modeling of range-dependent environments in elastic layered media. For problems with large contrasts, accuracy and efficiency are gained by subdividing vertical interfaces into a series of two or more single-scattering problems. This approach generates several computational parameters, such as the number of interface slices, an iteration convergence parameter τ, and the number of iterations n for convergence. Using a narrow-angle approximation, the choices of n=1 and τ=2 give accurate solutions. Analogous results from the narrow-angle approximation extend to environments with larger variations when slices are used as needed at vertical interfaces. The approach is applied to a generic ocean waveguide that includes the generation of a Rayleigh interface wave. Results are presented in both frequency and time domains.
Rayleigh scattering by H2 in the extrasolar planet HD209458b
Etangs, A Lecavelier des; Desert, J -M; Sing, D
2008-01-01
Transiting planets, such as HD209458b, offer a unique opportunity to scrutinize the planetary atmospheric content. Although molecular hydrogen is expected to be the main atmospheric constituent, H2 remains uncovered because of the lack of strong transition from near-ultraviolet to near-infrared. Here we analyse the absorption spectrum of HD209458b obtained by Sing et al. (2008a) which provides a measurement of the absorption depth in the 3000-6200 AA wavelength range. We show that the rise in absorption depth at short wavelengths can be interpreted as Rayleigh scattering within the atmosphere of HD209458b. Since Rayleigh scattering traces the entire atmosphere, this detection enables a direct determination of the pressure-altitude relationship, which is required to determine the absolute fraction of other elements such as sodium. At the zero altitude defined by the absorption depth of 1.453%, which corresponds to a planetary radius of 0.1205 times the stellar radius, we find a pressure of 33+/-5 mbar. Using t...
Distributed stress and temperature sensing based on Rayleigh scattering of low-coherence light
Gorshkov, B. G.; Taranov, M. A.; E Alekseev, A.
2017-08-01
A novel arrangement for fiber optic distributed stress and temperature sensing based on the Rayleigh scattering spectra correlation method is proposed. The principal feature of the arrangement is usage of low-coherence light in probe pulses, which ensures a wide dynamic range for measurements at moderate sensitivity. Such a characteristic corresponds to performance specifications for infrastructure monitoring systems. A theory of optical time domain reflectometry for arbitrary coherence light is developed describing the contrast in reflectograms and Rayleigh scattering spectra properties. The experimental setup uses a wideband source of light pulses and an electronically controlled micro-electro-mechanical system optical filter for wavelength tuning. Temperature change experiments show root mean square (RMS) noise levels of 0.13 °C, 0.24 °C and 0.3 °C for fiber lengths of 2 km, 8 km and 25 km, respectively, at a spatial resolution of about 1 m (for 10 min data collection). As much as 2000 µstrain dynamic range is demonstrated in the stress measurement experiment while the noise level (RMS error) is estimated to be 2 µstrain. Our experimental results are compared with the theory and a satisfactory match is demonstrated.
Birkedal, Dan; Shah, Jagdeep; Pfeiffer, L. N.
1999-01-01
Recent investigations of secondary emission from quantum well excitons following ultrafast resonant excitation have demonstrated an intricate interplay of coherent Rayleigh scattering and incoherent luminescence. We have very recently demonstrated that it is possible to isolate and time resolve...... the coherent field associated with Rayleigh component using ultrafast spectral interferometry or Tadpole, thus, obtaining substantial and new information of the nature of resonant secondary emission. Our observation demonstrates that Rayleigh scattering from static disorder is inherently a non-ergodic process...... invalidating the use of current theories using ensemble averages to describe our observations. Furthermore, we report here a new and hitherto unknown coherent scattering mechanism involving the two-photon coherence associated with the biexciton transition. The process leaves an exciton behind taking up...
2007-01-01
In pH 4.5 Britton-Robinson(BR)buffer solution,erythrosin(ET)can react with diphenhydramine(DP)to form a 1:1 ion-association complex,which not only results in the change of the absorption spectra,but also results in the great enhancement of resonance Rayleigh scattering(RRS)and the quenching of fluorescence.Furthermore,a new RRS spectrum will appear,and the maximum RRS wavelength was located at about 580 nm.In this work,the spectral characteristics of the absorption,fluorescence and RRS,the optimum conditions of the reaction and the properties of an analytical chemistry were inves- tigated.A sensitive,simple and new method for the determination of DP by using erythrosin as a probe has been developed.The detection limits for DP were 0.0020μg/mL for RRS method,0.088μg/mL for absorption method and 0.094μg/mL for fluorophotometry.There was a linear relationship between the absorbance,RRS and fluorescence intensities and the drug concentration in the range of 0.0067-2.0, 0.29-6.4 and 0.31-3.2μg/mL,respectively.The effects of the interaction of diphenhydramine and erythrosin on the absorption,fluorescence and resonance Rayleigh scattering spectra were discussed. In light polarization experiment,the polarization of RRS at maximum wavelength was measured to be P =0.9779,and it revealed that the RRS spectrum of DP-ET complex consists mostly of resonance scat- tering and few resonance fluorescence.In this study,enthalpy of formation and mean polarizability were calculated by AM1 quantum chemistry method.In addition,the reaction mechanism and the rea- sons for the enhancement of scattering spectra and the energy transfer between absorption,fluores- cence and RRS were discussed.
Conti, C.C., E-mail: ccconti@ird.gov.br [Institute for Radioprotection and Dosimetry – IRD/CNEN, Rio de Janeiro (Brazil); Physics Institute, State University of Rio de Janeiro – UERJ, Rio de Janeiro (Brazil); Anjos, M.J. [Physics Institute, State University of Rio de Janeiro – UERJ, Rio de Janeiro (Brazil); Salgado, C.M. [Nuclear Engineering Institute – IEN/CNEN, Rio de Janeiro (Brazil)
2014-09-15
Highlights: •This work describes a procedure for sample self-absorption correction. •The use of Monte Carlo simulation to calculate the mass attenuation coefficients curve was effective. •No need for transmission measurement, saving time, financial resources and effort. •This article provides de curves for the 90° scattering angle. •Calculation on-line at (www.macx.net.br). -- Abstract: X-ray fluorescence technique plays an important role in nondestructive analysis nowadays. The development of equipment, including portable ones, enables a wide assortment of possibilities for analysis of stable elements, even in trace concentrations. Nevertheless, despite of the advantages, one important drawback is radiation self-attenuation in the sample being measured, which needs to be considered in the calculation for the proper determination of elemental concentration. The mass attenuation coefficient can be determined by transmission measurement, but, in this case, the sample must be in slab shape geometry and demands two different setups and measurements. The Rayleigh to Compton scattering ratio, determined from the X-ray fluorescence spectrum, provides a link to the mass attenuation coefficient by means of a polynomial type equation. This work presents a way to construct a Rayleigh to Compton scattering ratio versus mass attenuation coefficient curve by using the MCNP5 Monte Carlo computer code. The comparison between the calculated and literature values of the mass attenuation coefficient for some known samples showed to be within 15%. This calculation procedure is available on-line at (www.macx.net.br)
A molecular Rayleigh scattering setup to measure density fluctuations in thermal boundary layers
Panda, J.
2016-12-01
A Rayleigh scattering-based density fluctuation measurement system was set up inside a low-speed wind tunnel of NASA Ames Research Center. The immediate goal was to study the thermal boundary layer on a heated flat plate. A large number of obstacles had to be overcome to set up the system, such as the removal of dust particles using air filters, the use of photoelectron counting electronics to measure low intensity light, an optical layout to minimize stray light contamination, the reduction in tunnel vibration, and an expanded calibration process to relate photoelectron arrival rate to air density close to the plate surface. To measure spectra of turbulent density fluctuations, a two-PMT cross-correlation system was used to minimize the shot noise floor. To validate the Rayleigh measurements, temperature fluctuations spectra were calculated from density spectra and then compared with temperature spectra measured with a cold-wire probe operated in constant current mode. The spectra from the downstream half of the plate were found to be in good agreement with cold-wire probe, whereas spectra from the leading edge differed. Various lessons learnt are discussed. It is believed that the present effort is the first measurement of density fluctuations spectra in a boundary layer flow.
Mielke, Amy F.; Seasholtz, Richard G.; Elam, Kristie A.; Panda, Jayanta
2005-01-01
Nonintrusive optical point-wise measurement techniques utilizing the principles of molecular Rayleigh scattering have been developed at the NASA Glenn Research Center to obtain time-averaged information about gas velocity, density, temperature, and turbulence, or dynamic information about gas velocity and density in unseeded flows. These techniques enable measurements that are necessary for validating computational fluid dynamics (CFD) and computational aeroacoustic (CAA) codes. Dynamic measurements allow the calculation of power spectra for the various flow properties. This type of information is currently being used in jet noise studies, correlating sound pressure fluctuations with velocity and density fluctuations to determine noise sources in jets. These nonintrusive techniques are particularly useful in supersonic flows, where seeding the flow with particles is not an option, and where the environment is too harsh for hot-wire measurements.
The fluorescence quenching and resonance Rayleigh scattering enhancement of ET-CPM system
YANG JiDong; ZHOU Shang
2009-01-01
In pH 4.4 BR buffer medium, erythrosine (ET) and Chlorphensmine Maleate (CPM) could form ion-as-sociation complex, which led to the quenching of fluorescence and synchronous fluorescence, and the significant enhancement of resonance Rayleigh scattering(RRS) of erythrosine. Furthermore, a new RRS spectrum would appear, and the maximum RRS wavelength was located at about 578 rim. The quenched fluorescence and enhanced RRS intensity was directly proportional to the concentration of CPM in the ranges of 0.24-8.0 μg/mL, and 0.008-3.6 μg/mL, respectively. The method has been ap-plied to determine CPM in urine samples with satisfactory results. The mechanisms of the RRS en-hancement and fluorescence quenching were discussed as well.
Tallur, Siddharth
2013-01-01
Finite photon lifetimes for light fields in an opto-mechanical cavity impose a bandwidth limit on displacement sensing at mechanical resonance frequencies beyond the loaded cavity photon decay rate. Opto-mechanical modulation efficiency can be enhanced via multi-GHz transduction techniques such as piezo-opto-mechanics at the cost of on-chip integration. In this paper, we present a novel high bandwidth displacement sense scheme employing Rayleigh scattering in photonic resonators. Using this technique in conjunction with on-chip electrostatic drive in silicon enables efficient modulation at frequencies up to 9.1GHz. Being independent of the drive mechanism, this scheme could readily be extended to piezo-opto-mechanical and all optical transduced systems.
Rayleigh scattering of Moessbauer radiation in oriented fibres of hydrated biopolymers
Albanese, G. [Parma Univ. (Italy). Ist. di Fisica; Deriu, A. [Parma Univ. (Italy). Ist. di Fisica; Cavatorta, F. [Parma Univ. (Italy). Ist. di Fisica; Rupprecht, A. [Stockholm Univ. (Sweden). Dept. of Physical, Inorganic and Structural Chemistry
1995-03-01
The Rayleigh scattering of Moessbauer radiation (RSMR) has been measured on films of highly oriented hydrated polynucleotides (A-NaDNA) and polysaccharides (Na-hyaluronate). Both DNA and hyaluronate (HA) have helical secondary structures with a similar pitch (28.2 A for A-DNA, and 32.8 A for Na-HA), but they differ in the basic elements which make up the helices and in the extent of water-biopolymer interactions. These differences are responsible for the diverse stiffness of the polymer backbone, and also affect the dynamics of the first hydration layers. For both samples the elastic scattering intensity shows a sharp peak at about 2 A{sup -1} only for samples oriented with Q parallel to the fibre direction. Its position is close to that of the first maximum in the structure factor of bulk water; it is, however, much narrower than in pure H{sub 2}O and it is similar to a crystalline Bragg peak. It can be attributed to an ordered structure of water along the double helices. From the temperature dependence of the elastic intensity under the peak maximum, the mean square displacement of water oxygens in the direction parallel to the helices has been deduced. The thermal diffuse scattering intensity is also peaked at the same Q values of the elastic intensity, indicating the presence of coherent vibrational excitations propagating along the ordered water filaments. (orig.)
Birkedal, Dan; Shah, Jagdeep; Pfeiffer, L. N.
1999-01-01
Recent investigations of secondary emission from quantum well excitons following ultrafast resonant excitation have demonstrated an intricate interplay of coherent Rayleigh scattering and incoherent luminescence. We have very recently demonstrated that it is possible to isolate and time resolve...... invalidating the use of current theories using ensemble averages to describe our observations. Furthermore, we report here a new and hitherto unknown coherent scattering mechanism involving the two-photon coherence associated with the biexciton transition. The process leaves an exciton behind taking up...
Beresh, Steven Jay; Grasser, Thomas W.; Kearney, Sean Patrick; Schefer, Robert W.
2004-01-01
Simulation-based life-cycle-engineering and the ASCI program have resulted in models of unprecedented size and fidelity. The validation of these models requires high-resolution, multi-parameter diagnostics. Within the thermal-fluids disciplines, the need for detailed, high-fidelity measurements exceeds the limits of current engineering sciences capabilities and severely tests the state of the art. The focus of this LDRD is the development and application of filtered Rayleigh scattering (FRS) for high-resolution, nonintrusive measurement of gas-phase velocity and temperature. With FRS, the flow is laser-illuminated and Rayleigh scattering from naturally occurring sources is detected through a molecular filter. The filtered transmission may be interpreted to yield point or planar measurements of three-component velocities and/or thermodynamic state. Different experimental configurations may be employed to obtain compromises between spatial resolution, time resolution, and the quantity of simultaneously measured flow variables. In this report, we present the results of a three-year LDRD-funded effort to develop FRS combustion thermometry and Aerosciences velocity measurement systems. The working principles and details of our FRS opto-electronic system are presented in detail. For combustion thermometry we present 2-D, spatially correlated FRS results from nonsooting premixed and diffusion flames and from a sooting premixed flame. The FRS-measured temperatures are accurate to within {+-}50 K (3%) in a premixed CH4-air flame and within {+-}100 K for a vortex-strained diluted CH4-air diffusion flame where the FRS technique is severely tested by large variation in scattering cross section. In the diffusion flame work, FRS has been combined with Raman imaging of the CH4 fuel molecule to correct for the local light scattering properties of the combustion gases. To our knowledge, this is the first extension of FRS to nonpremixed combustion and the first use of joint FRS
Shi, Ying; Yang, Liu; Zhu, Jinghui; Yang, Jidong; Liu, Shaopu; Qiao, Man; Duan, Ruilin; Hu, Xiaoli
2017-02-01
Carbon dots (CDs) are raising a substantial amount of attention owing to their many unique and novel physicochemical properties. Herein one-pot synthesized CDs, to the best of our knowledge, were first served as the robust nanoprobe for detection tannic acid (TA) based on resonance Rayleigh scattering technique. The as-prepared CDs can combine with TA via hydrogen bond, resulting in remarkable enhancement of scattering signal with no changes in the fluorescence of CDs. Therefore, a novel protocol for TA determination was established and this strategy allowed quantitative detection of TA in the linear range of 0.2-10.0 μmol L- 1 with an excellent detection limit of 9.0 nmol L- 1. Moreover, the CDs based nanoprobe can be applied to the determination of TA in water sample with satisfactory results. Our study can potentially influence our current views on CDs and particularly impressive and offers new insights into application of CDs beyond the traditional understanding of CDs.
Highly efficient and two-photon excited stimulated Rayleigh-Bragg scattering in organic solutions
He, Guang S., E-mail: gshe@buffalo.edu; Prasad, Paras N. [The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo, Buffalo, New York 14260-3000 (United States); Kannan, Ramamurthi; Tan, Loon-Seng [Air Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/RX, Wright-Patterson AFB, Ohio 45433-7750 (United States)
2015-07-21
The properties of backward stimulated Rayleigh-Bragg scattering (SRBS) in three highly two-photon active AF-chromophores solutions in tetrahydrofuran (THF) have been investigated using 816-nm and 8-ns pump laser beam. The nonlinear reflectivity R, spectral structure, temporal behavior, and phase-conjugation capability of the backward SRBS output have been measured, respectively. Under the same experimental condition, the pump threshold for SRBS in three solution samples can be significantly (∼one order of magnitude) lower than that for stimulated Brillouin scattering (SBS) in the pure solvent (THF). With the optimized concentration value and at a moderate pump energy (∼1.5 mJ) level, the measured nonlinear reflectivity was R ≥ 35% for the 2 cm-long solution sample, while for the SBS from a pure solvent sample of the same length was R ≈ 4.7%. The peculiar features of very low pump threshold, no spectral shift, tolerant pump spectral linewidth requirement (≤1 cm{sup −1}), and phase-conjugation capability are favorable for those nonlinear photonics applications, such as highly efficiency phase-conjugation reflectors for high-brightness laser oscillator/amplifier systems, special imaging through turbid medium, self-adaptive remote optical sensing, as well as for optical rangefinder and lidar systems.
Ogawa, Y., E-mail: y.ogawa@ap.titech.ac.jp [Department of Physics, Tokyo Institute of Technology, Oh-Okayama 2-12-1, Tokyo 152-8551 (Japan); Takahashi, S.; Nakajima, D.; Minami, F. [Department of Physics, Tokyo Institute of Technology, Oh-Okayama 2-12-1, Tokyo 152-8551 (Japan)
2013-01-15
Surface plasmon polariton (SPP) propagation on a Au thin film has been observed by tip-enhanced Rayleigh scattering. The interference pattern has been observed around the edge of the film. The interference is due to the near-field scattering light at the tip and SPP radiation from the edge of the film. From the interference width, we evaluated the wave number of SPP on the Au film. By changing the wavelength of the incidence light, we have obtained the dispersion relation of the SPP. The experimentally obtained dispersion relation is well corresponding to the calculated one using bulk Au parameters. - Highlights: Black-Right-Pointing-Pointer We observed surface plasmon polariton propagation on Au film by tip-enhanced Rayleigh scattering. Black-Right-Pointing-Pointer The dispersion relation was obtained by changing the wavelength of the incidence light. Black-Right-Pointing-Pointer The dispersion relation is well corresponding to the calculated one using bulk Au parameters.
High Prandtl number effect on Rayleigh-Bénard convection heat transfer at high Rayleigh number
Ma, Li; Li, Jing; Ji, Shui; Chang, Huajian
2017-02-01
This paper represents results of the Rayleigh-Bénard convection heat transfer in silicon oil confined by two horizontal plates, heated from below, and cooled from above. The Prandtl numbers considered as 100-10,000 corresponding to three types of silicon oil. The experiments covered a range of Rayleigh numbers from 2.14·109 to 2.27·1013. The data points that the Nusselt number dependents on the Rayleigh number, which is asymptotic to a 0.248 power. Furthermore, the experiment results can fit the data in low Rayleigh number well.
Jagodzinski, Jeremy James
2007-12-01
The development to date of a diode-laser based velocimeter providing point-velocity-measurements in unseeded flows using molecular Rayleigh scattering is discussed. The velocimeter is based on modulated filtered Rayleigh scattering (MFRS), a novel variation of filtered Rayleigh scattering (FRS), utilizing modulated absorption spectroscopy techniques to detect a strong absorption of a relatively weak Rayleigh scattered signal. A rubidium (Rb) vapor filter is used to provide the relatively strong absorption; alkali metal vapors have a high optical depth at modest vapor pressures, and their narrow linewidth is ideally suited for high-resolution velocimetry. Semiconductor diode lasers are used to generate the relatively weak Rayleigh scattered signal; due to their compact, rugged construction diode lasers are ideally suited for the environmental extremes encountered in many experiments. The MFRS technique utilizes the frequency-tuning capability of diode lasers to implement a homodyne detection scheme using lock-in amplifiers. The optical frequency of the diode-based laser system used to interrogate the flow is rapidly modulated about a reference frequency in the D2-line of Rb. The frequency modulation is imposed on the Rayleigh scattered light that is collected from the probe volume in the flow under investigation. The collected frequency modulating Rayleigh scattered light is transmitted through a Rb vapor filter before being detected. The detected modulated absorption signal is fed to two lock-in amplifers synchronized with the modulation frequency of the source laser. High levels of background rejection are attained since the lock-ins are both frequency and phase selective. The two lock-in amplifiers extract different Fourier components of the detected modulated absorption signal, which are ratioed to provide an intensity normalized frequency dependent signal from a single detector. A Doppler frequency shift in the collected Rayleigh scattered light due to a change
Zhang Lei [Chemistry and Chemical Engineering, Southwest University, 400715 Chongqing (China); Peng Jingdong, E-mail: hxpengjd@swu.edu.cn [Chemistry and Chemical Engineering, Southwest University, 400715 Chongqing (China); Tang Jinxia; Yuan Binfang; He Rongxing; Xiao Ying [Chemistry and Chemical Engineering, Southwest University, 400715 Chongqing (China)
2011-11-14
Graphical abstract: Theoretical and experimental analysis had proved that aminoglycosides reacted with Congo red to form binary compounds simultaneously, which led to a novel HPLC-RRS strategy being applied in substances which are not fluorescing and not UV absorbed. Highlights: {yields} A novel HPLC-RRS strategy was shown in this study. {yields} Theoretical and experimental analysis had proved the feasibility of this method. {yields} Because of its specificity, no interference from the matrix was observed. {yields} The analytes in biological matrix were all well resolved without any interference. {yields} It provided new insights for analytes lack of useful spectroscopic and electrochemical properties. - Abstract: In view of the fact that many substances generally exhibit very little ultraviolet absorbance and the absence of native fluorescence, a new strategy with simple instrumentation and excellent analytical performance combining high performance liquid chromatography (HPLC) with resonance Rayleigh scattering (RRS) was developed. It was validated for the quantification of aminoglycosides (AGs). This fact was also carefully calculated by quantum chemistry. However, the sensitivity was probably limited by the volume of flow-through cell. Therefore, the result calls for a suitable one to ensure optimal RRS signal. Interestingly, when serum or urine samples of analytes were analyzed by this method, they were all well resolved without any interference, which would hold a new perspective to be applied in the determination of substances in biological matrix.
Truong, Phuoc Long; Choi, Seung Phill; Sim, Sang Jun
2013-10-25
A strategy for attomolar-level detection of small molecule-size proteins is reported based on Rayleigh light scattering spectroscopy of individual nanoplasmonic aptasensors by exploiting the outstanding characteristics of gold colloids to amplify the nontransparent resonant signal at ultralow analyte concentrations. The fabrication method utilizes thiol-mediated adsorption of a DNA aptamer on the immobilized Au nanoparticle surface, the interfacial binding characteristics of the aptamer with its target molecules, and the antibody-antigen interaction through plasmonic resonance coupling of the Au nanoparticles. Using lysozyme as a model analyte for disease detection, the detection limit of the aptasensor is ∼7 × 10(3) aM, corresponding to the LSPR λmax shift of ∼2.25 nm. Up to a 380% increase in the localized resonant λmax shift is demonstrated upon antibody binding to the analyte compared to the primary response during signal amplification using immunogold colloids. This enhancement leads to a limit of detection of ∼7 aM, which is an improvement of three orders of magnitude. The results demonstrate substantial promise for developing coupled plasmonic nanostructures for ultrasensitive detection of various biological and chemical analytes. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Wu, Huan; Zhao, Yanmei; Tan, Xuanping; Huang, Yunmei; Yuan, Haiyan; Yang, Jidong
2017-09-01
A convenient method for determination of malathion (Mala) based on resonance Rayleigh scattering (RRS) enhancement of L-Tryptophan (L-Try)-Pd(II)-Mala system was proposed in this paper. The interaction between L-Try, Pd(II) and malathion in the system was investigated by fluorescence, RRS and UV-Vis absorption spectroscopy. In the optimum conditions, the RRS intensity of L-Try-Pd(II)-Mala system had a remarkable enhancement because the hydrolysis products of malathion would interact with Pd(II) and L-Try each other formed new complexes, which enhanced intensity was directly proportional to the malathion concentration within a certain range. Based on the RRS enhancement of L-Try-Pd(II) system by Mala, a novel, convenient and specific method for Mala determination was developed. To our knowledge, the method is the first RRS method for determination of Mala was reported. The detection limit for Mala was 6.7 ng/mL and the quantitative determination range was 0.06-0.6 μg/mL. The influence of coexisting substances on RRS was also investigated, and the RRS method exhibited good anti-interference ability. The new analytical method has been applied to determine of malathion in real samples with satisfactory results.
Search for Rayleigh scattering in the atmosphere of GJ1214b
de Mooij, Ernst J W; de Kok, Remco J; Snellen, Ignas A G; Croll, Bryce; Jayawardhana, Ray; Hoekstra, Henk; Otten, Gilles P P L; Bekkers, David H; Haffert, Sebastiaan Y; van Houdt, Josha J
2013-01-01
We investigate the atmosphere of GJ1214b, a transiting super-Earth planet with a low mean density, by measuring its transit depth as a function of wavelength in the blue optical portion of the spectrum. It is thought that this planet is either a mini-Neptune, consisting of a rocky core with a thick, hydrogen-rich atmosphere, or a planet with a composition dominated by water. Most observations favor a water-dominated atmosphere with a small scale-height, however, some observations indicate that GJ1214b could have an extended atmosphere with a cloud layer muting the molecular features. In an atmosphere with a large scale-height, Rayleigh scattering at blue wavelengths is likely to cause a measurable increase in the apparent size of the planet towards the blue. We observed the transit of GJ1214b in the B-band with the FOcal Reducing Spectrograph (FORS) at the Very Large Telescope (VLT) and in the g-band with both ACAM on the William Hershel Telescope (WHT) and the Wide Field Camera (WFC) at the Isaac Newton Tele...
Singh, Anant K; Senapati, Dulal; Wang, Shuguang; Griffin, Jelani; Neely, Adria; Candice, Perry; Naylor, Khaleah M; Varisli, Birsen; Kalluri, Jhansi Rani; Ray, Paresh Chandra
2009-07-28
The presence of E. coli in foodstuffs and drinking water is a chronic worldwide problem. The worldwide food production industry is worth about U.S. $578 billion, and the demand for biosensors to detect pathogens and pollutants in foodstuffs is growing day by day. Driven by the need, we report for the first time that two-photon Rayleigh scattering (TPRS) properties of gold nanorods can be used for rapid, highly sensitive and selective detection of Escherichia coli bacteria from aqueous solution, without any amplification or enrichment in 50 colony forming units (cfu)/mL level with excellent discrimination against any other bacteria. TPRS intensity increases 40 times when anti- E. coli antibody-conjugated nanorods were mixed with various concentrations of Escherichia coli O157:H7 bacterium. The mechanism of TPRS intensity change has been discussed. This bionanotechnology assay could be adapted in studies using antibodies specific for various bacterial pathogens for the detection of a wide variety of bacterial pathogens used as bioterrorism agents in food, clinical samples, and environmental samples.
HE Youqiu; LIU Shaopu; LIU Qin; LIU Zhongfang; HU Xiaoli
2005-01-01
The interaction between gold nanoparticle and safranine T (ST) has been studied with resonance Rayleigh scattering (RRS) spectra, absorption and fluorescence spectra. In the pH 5 solution, citrate [(H2L)2-] self-assembles on the surface of positively-charged gold nanoparticle, which results in the [(Au)n(H2L)m]x- complex. In other words, one of carboxylate oxygens in (H2L)2- moves inward and combines with gold nanoparticle. The other carboxylate oxygens moves outward to form a supermolecular complex anion with x negative charges. Then by virtue of electrostatic attraction, hydrophobic force and charge transfer action, the complex anion binds with ST cation to form a new ion-association complex. Here (H2L)2- acts as a bridge. The formation of the complex results in the significant enhancement of RRS intensity, the appearance of new RRS spectrum, the red shift of plasma absorption band of gold nanoparticle as well as the decrease in the absorbance and fluorescence quenching for safranine T. In this work, the interaction between gold nanoparticle and ST on the RRS, absorption and fluorescence spectra has been investigated. The reason why RRS intensity increases greatly and the reaction mechanism have been inquired. The results show that RRS spectra can not only be used to study nanoparticle and reaction product, but also are a sensitive means to characterize and detect nanoparticles.
Hydride generation-resonance Rayleigh scattering and SERS spectral determination of trace Bi
Liang, Xiaojing; Wen, Guiqing; Liu, Qingye; Liang, Aihui; Jiang, Zhiliang
2016-09-01
In acidic solutions, Bi(III) was reduced by NaBH4 to form BiH3 gas. Using I3- graphene oxide (GO) as absorption solution, the BiH3 gas reacted with I3- to form I- that resulted in the I3- concentration decreasing. In the absence of BiH3, the I3- concentration was high, and as receptors it was closed to the surfaces of GO which was as donors. Then the surface plasmon resonance Rayleigh scattering (RRS) energy of GO transfers to I3- heavily, and results in the RRS quenching severely. With the increase of the Bi(III) concentration, the receptors and the RRS energy transfer (RRS-ET) decreased, so the RRS intensity enhanced linearly at 370 nm. The RRS intensity was linear to the Bi(III) concentration in 0.05-5.5 μmol/L, with a detection limit of 4 ng/mL Bi. A new RRS-ET spectral method was developed for the determination of trace Bi(III). Using I3- as the absorption solution, silver nanorod (AgNR) as sol substrate and Vitoria blue B (VBB) as molecular probe, a SERS method was developed for detection of Bi.
Rayleigh scattering by aqueous colloidal silica as a cause for the blue color of hydrothermal water
Ohsawa, Shinji; Kawamura, Takao; Takamatsu, Nobuki; Yusa, Yuki
2002-03-01
Thermal waters in hydrothermal ponds, bathing pools and the brines of geothermal electric power plants commonly have a characteristic blue color. Although many researchers have assumed that the blue color is due to a colloidal suspension and/or absorption by dissolved ferrous iron or by water itself, there has been no specific effort to identify the physical nature of this phenomenon. We have tested, in synthetic and natural solutions, whether aqueous colloidal silica is responsible for the blue color. Aqueous colloidal silica is formed by silica polymerization in thermal waters of the neutral-chloride type which contain initially monomeric silica in concentrations up to three times above the solubilities of amorphous silica. The hue of the blue thermal waters in the pools tested agrees with that of a synthesized colloidal silica solution. Grain-size analyses of aqueous colloidal silica in the blue-colored thermal waters demonstrate that the color is caused by Rayleigh scattering from aqueous colloidal silica particles with diameters (0.1-0.45 μm) smaller than the wavelengths of visible radiation.
Veniaminov, Andrey V.; Sillescu, Hans
1999-04-01
Tracer diffusion of 9,10-phenanthrenequinone (PQ) and its photoproduct in super-cooled phenolphthalein-dimethyl-ether (PDE) was studied by forced Rayleigh scattering. In order to investigate the spatial frequency dependence of the grating dynamics, several spatial harmonics of the grating with non-sinusoidal phase profile produced by non-linear recording were monitored. An optical scheme with a diverging reading beam is proposed for simultaneous reconstruction of the harmonic components.
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.
Doll, Ulrich; Burow, Eike; Beversdorff, Manfred; Stockhausen, Guido; Willert, Christian; Morsbach, Christian; Schlüß, Daniel; Franke, Martin
2015-01-01
The flow field of a Ranque-Hilsch vortex tube is characterized experimentally. Firstly conventional probe based technology is used in order to measure inlet and outlet temperatures as well as to acquire temporally resolved wall pressure data over a wide range of operating conditions. Secondly the filtered Rayleigh scattering technique is employed in order to gather detailed temporally averaged planar information on the vortex tube’s flow topology. These measurements form the basis of a detail...
Zhou, Mingqiong; Peng, Jingdong; He, Rongxing; He, Yuting; Zhang, Jing; Li, Aiping
2015-02-01
A reliable and versatile high performance liquid chromatography coupled with resonance Rayleigh scattering method was established for the determination of three fluoroquinolones, including levofloxacin, norfloxacin and enrofloxacin in water sample and human urine sample. In pH 4.4-4.6 Britton-Robinson buffer medium, the fluoroquinolones separated by high performance liquid chromatography could react with erythrosine to form 1:1 ion-association complexes, which could make contributions to the great enhancement of RRS. The resonance Rayleigh scattering signal was recorded at λex = λem = 330 nm. The resonance Rayleigh scattering spectral characteristics of the drugs and the experimental conditions such as pH, detection wavelength, erythrosine concentration, flow rate, the length of reaction tube were studied. Quantum chemistry calculation, Fourier transform infrared spectroscopy and absorption spectroscopy were used to discuss the reaction mechanism. The recoveries of samples added standard ranged from 97.53% to 102.00%, and the relative standard deviation was below 4.64%. The limit of detection (S/N = 3) of 0.05-0.12 μg mL-1 was reached, and the linear regression coefficients were all above 0.999. The proposed method was proved as a simple, low cost and high sensitivity method.
Tian, Fengling; Huang, Wei; Yang, Jidong; Li, Qin
In pH 3.25-3.35 Britton-Robinson (BR) buffer solution, albendazole (ABZ) could react with eosin Y (EY) to form a 1:1 ion-association complex, which not only results in the quenching of fluorescence, but also resulted in the great enhancement of resonance Rayleigh scattering (RRS) and frequency doubling scattering (FDS). Furthermore, a new RRS spectrum will appear, and the maximum RRS wavelength was located at about 356 nm. The detection limit for ABZ were 21.51 ng mL-1 for the fluorophotometry, 6.93 ng mL-1 for the RRS method and 12.89 ng mL-1 for the FDS method. Among them, the RRS method had the highest sensitivity. The experimental conditions were optimized and effects of coexisting substances were evaluated. Meanwhile, the influences of coexisting substances were tested. The methods have been successfully applied to the determination of ABZ in capsules and human urine samples. The composition and structure of the ion-association complex and the reaction mechanism were discussed.
Xiaoyi Bao
2013-01-01
Full Text Available A distributed optical fiber sensor with the capability of simultaneously measuring temperature and strain is proposed using a large effective area non-zero dispersion shifted fiber (LEAF with sub-meter spatial resolution. The Brillouin frequency shift is measured using Brillouin optical time-domain analysis (BOTDA with differential pulse-width pair technique, while the spectrum shift of the Rayleigh backscatter is measured using optical frequency-domain reflectometry (OFDR. These shifts are the functions of both temperature and strain, and can be used as two independent parameters for the discrimination of temperature and strain. A 92 m measurable range with the spatial resolution of 50 cm is demonstrated experimentally, and accuracies of ±1.2 °C in temperature and ±15 με in strain could be achieved.
SEARCH FOR RAYLEIGH SCATTERING IN THE ATMOSPHERE OF GJ1214b
De Mooij, E. J. W.; Jayawardhana, R. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Brogi, M.; Snellen, I. A. G.; Hoekstra, H.; Otten, G. P. P. L.; Bekkers, D. H.; Haffert, S. Y.; Van Houdt, J. J. [Leiden Observatory, Leiden University, Postbus 9513, 2300-RA, Leiden (Netherlands); De Kok, R. J. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584-CA, Utrecht (Netherlands); Croll, B., E-mail: demooij@astro.utoronto.ca [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
2013-07-10
We investigate the atmosphere of GJ1214b, a transiting super-Earth planet with a low mean density, by measuring its transit depth as a function of wavelength in the blue optical portion of the spectrum. It is thought that this planet is either a mini-Neptune, consisting of a rocky core with a thick, hydrogen-rich atmosphere, or a planet with a composition dominated by water. Most observations favor a water-dominated atmosphere with a small scale-height, however, some observations indicate that GJ1214b could have an extended atmosphere with a cloud layer muting the molecular features. In an atmosphere with a large scale-height, Rayleigh scattering at blue wavelengths is likely to cause a measurable increase in the apparent size of the planet toward the blue. We observed the transit of GJ1214b in the B band with the FOcal Reducing Spectrograph at the Very Large Telescope and in the g band with both ACAM on the William Herschel Telescope (WHT) and the Wide Field Camera at the Isaac Newton Telescope (INT). We find a planet-to-star radius ratio in the B band of 0.1162 {+-} 0.0017, and in the g band 0.1180 {+-} 0.0009 and 0.1174 {+-} 0.0017 for the WHT and INT observations, respectively. These optical data do not show significant deviations from previous measurements at longer wavelengths. In fact, a flat transmission spectrum across all wavelengths best describes the combined observations. When atmospheric models are considered, a small scale-height water-dominated model fits the data best.
Gerakis, A.; Shneider, M. N.; Stratton, B. C.; Santra, B.; Car, R.; Raitses, Y.
2016-09-01
Laser-based diagnostics methods, such as Spontaneous and Coherent Rayleigh and Rayleigh-Brillouin scattering (SRBS and CRBS), can be used for in-situ detection and characterization of nanoparticle shape and size as well as their concentration in an inert gas atmosphere. We recently developed and tested this advanced diagnostic at PPPL. It was shown that the signal intensity of the CRBS signal depends on the gas-nanoparticle mixture composition, density and the polarizabilities of the mixture components. The measured results agree well with theoretical predictions of Refs. In this work, we report the application of this diagnostic to monitor nucleation and growth of nanoparticles in a carbon arc discharge. In support of these measurements, A time-dependent density functional theory was used to compute the frequency-dependent polarizabilities of various nanostructures in order to predict the corresponding Rayleigh scattering intensities as well as light depolarization. Preliminary results of measurements demonstrate that CRBS is capable to detect nanoparticles in volume. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.
Pandey, Ravindra; Ghosh, Sampa; Mukhopadhyay, S; Ramasesha, S; Das, Puspendu K
2011-01-28
We report large quadratic nonlinearity in a series of 1:1 molecular complexes between methyl substituted benzene donors and quinone acceptors in solution. The first hyperpolarizability, β(HRS), which is very small for the individual components, becomes large by intermolecular charge transfer (CT) interaction between the donor and the acceptor in the complex. In addition, we have investigated the geometry of these CT complexes in solution using polarization resolved hyper-Rayleigh scattering (HRS). Using linearly (electric field vector along X direction) and circularly polarized incident light, respectively, we have measured two macroscopic depolarization ratios D=I(2ω,X,X)/I(2ω,Z,X) and D(')=I(2ω,X,C)/I(2ω,Z,C) in the laboratory fixed XYZ frame by detecting the second harmonic scattered light in a polarization resolved fashion. The experimentally obtained first hyperpolarizability, β(HRS), and the value of macroscopic depolarization ratios, D and D('), are then matched with the theoretically deduced values from single and double configuration interaction calculations performed using the Zerner's intermediate neglect of differential overlap self-consistent reaction field technique. In solution, since several geometries are possible, we have carried out calculations by rotating the acceptor moiety around three different axes keeping the donor molecule fixed at an optimized geometry. These rotations give us the theoretical β(HRS), D and D(') values as a function of the geometry of the complex. The calculated β(HRS), D, and D(') values that closely match with the experimental values, give the dominant equilibrium geometry in solution. All the CT complexes between methyl benzenes and chloranil or 1,2-dichloro-4,5-dicyano-p-benzoquinone investigated here are found to have a slipped parallel stacking of the donors and the acceptors. Furthermore, the geometries are staggered and in some pairs, a twist angle as high as 30° is observed. Thus, we have demonstrated in
Luchsinger, Kristen; Redfield, Seth; Cauley, Paul W.; Barman, Travis S.; Jensen, Adam G.
2017-01-01
When studying planetary atmospheres, scattering signatures, such as Rayleigh scattering, can often be the most easily characterized signal. This is especially true in terrestrial atmospheres, where Rayleigh scattering is the dominant spectral feature in optical wavelengths. These scattering signatures, unlike molecular or atomic line absorption, are broad and continuous, and are char- acterized by a single slope. Rayleigh scattering provides an imporant glimpse into the atmospheric composition of an exoplanet's atmosphere, and a Rayleigh scattering detection on a smaller, ground-based telescope can be a useful method to identify interesting science targets for larger, space-based telescopes.We will present observations of three exoplanets using the HYDRA multi- object spectrometer on the WIYN telescope at Kitt Peak National Observatory. We obtained two transits each for WASP 12b and GJ 3470b, and one transit for HD 189733b, for a range of wavelengths between 4500 Å and 9201 Å. A successful Rayleigh scattering detection in the atmospheres of these planets using this in- strument would represent a step forward in our current detection capabilities and open up the study of planetary atmospheres to smaller, ground-based telescopes.Data presented herein were obtained at the WIYN Observatory from telescope time allocated to NN-EXPLORE through the scientific partnership of the National Aeronautics and Space Administration, the National Science Foundation, and the National Optical Astronomy Observatory. This work was supported by a NASA WIYN PI Data Award, administered by the NASA Exoplanet Science Institute.
LI TaiShan; LIU ShaoPu; LIU ZhongFang; HU XiaoLi; ZHANG LiPing
2009-01-01
CdTe nanocrystals (CdTe NCs) were achieved by reaction of CdCl2 with KHTe solution and were capped with sodium mercaptoacetate. The product was detected by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), fluorescence spectra, ultraviolet-visible spectra and X-ray diffraction (XRD). The CdTe NCs are of cubic structure and the average size is about 5 nm. The fluorescence quantum yield of CdTe NCs aqueous solution increased from 37% to 97% after 20 d under room light. The maximum λem of fluorescence changed from 543 nm to 510 nm and the blue shift was 33 nm. CdTe NCs aqueous solution can be steady for at least 10 months at 4℃ in a refrigerator. The resonance Rayleigh scattering (RRS) of CdTe NCs in the aqueous solution was investigated. The maximum scattering peak was located at about 554 nm. The interactions of CdTe NCs with amikacin sulfate (AS) and micronomicin sulfate (MS) were in-vestigated respectively. The effects of AS and MS on fluorescence and RRS of CdTe NCs were analyzed. It was found that AS and MS quenched the photoluminescence of CdTe NCs and enhanced RRS of CdTe NCs. Under optimum conditions, there are linear relationships between quenching intensity (F0-F), intensity of RRS (1-10) and concentration of AS and MS. The detection limits (3σ) of AS and MS are re-spectively 3.4 ng.mL-1 and 2.6 ng.mL-1 by the fluorescence quenching method, and 15.2 ng.mL-1 and 14.0 ng.mL-1 by the RRS method. The methods have high sensitivity, thus CdTe NCs may be used as fluorescence probes and RRS probes for the detection of aminoglycoside antibiotics.
LIU; Shaopu; HU; Xiaoli; LIU; Zhongfang
2006-01-01
The interaction between congo red (CR) and amikacin (AMK) was studied by resonance Rayleigh scattering (RRS), frequency doubling scattering (FDS) and second-order scattering (SOS) combining with absorption spectrum. In a weak acidic medium, CR combined with AMK to form an ion association complex with the composition ratio of 1∶1 by electrostatic interaction, hydrophobicity and charge transferring effect. As a result, the new spectra of RRS, FDS, and SOS appeared and their intensities were enhanced greatly. The maximum wavelengths of RRS, FDS and SOS were located at 563 nm, 475 nm and 940 nm, and the scattering intensities were proportional to the concentration of AMK. These three methods have very high sensitivities, and the detection limits were 4.0 ng·mL(1 for RRS, 3.6 ng·mL(1 for FDS and 1.9 ng·mL-1 for SOS, respectively. At the same time, the methods have better selectivity. A new method for the determination of trace amounts of AMK with congo red by resonance scattering technique has been developed. The recovery for the determination of AMK in blood serum and urine sample was between 95.5% and 105.5%. In this study, the properties, such as enthalpy of formation, charge distribution and mean polarizability, were calculated by AM1 quantum chemistry method. In addition, the reaction mechanism and the reasons for the enhancement of scattering spectra were discussed.
Wang, Jian; Liu, Zhongfang; Liu, Jiangtao; Liu, Shaopu; Shen, Wei
2008-03-01
In pH 4.4-4.5 Britton-Robinson (BR) buffer solution, fluoroquinolone antibiotics (FLQs) including ciprofloxacin (CIP), norfloxacin (NOR), levofloxacin (LEV) and lomefloxacin (LOM) could react with erythrosine (Ery) to form 1:1 ion-association complexes, which not only resulted in the changes of the absorption spectra and the quenching of fluorescence, but also resulted in the great enhancement of resonance Rayleigh scattering (RRS). These offered some indications of the determination of fluoroquinolone antibiotics by spectrophotometric, fluorescence and resonance Rayleigh scattering methods. The detection limits for fluoroquinolone antibiotics were in the range of 0.097-0.265 μg/mL for absorption methods, 0.022-0.100 μg/mL for fluorophotometry and 0.014-0.027 μg/mL for RRS method, respectively. Among them, the RRS method had the highest sensitivity. In this work, the spectral characteristics of the absorption, fluorescence and RRS, the optimum conditions of the reactions and the properties of the analytical chemistry were investigated. The methods have been successfully applied to determination of some fluoroquinolone antibiotics in human urine samples and tablets. Taking CIP-Ery system as an example, the charge distribution, the enthalpy of formation and the mean polarizability were calculated by density function theory (DFT) method. In addition, the reasons for the enhancement of scattering spectra were discussed.
Yu ZHANG; Kun Ji CHEN; Xin WANG; Ming MA; De Gang FU; Ning GU; Ju Zheng LIU; Zu Hong LU; Ling XU; Jun XU
2003-01-01
The second-order optical nonlinearity of CdS nanoparticles with different diameters of28.0, 30.0, 31.5, 50.0, and 91.0 3 was studied by hyper-Rayleigh scattering technique. Resultsshow that the first-order hyperpolarizability β value per CdS particle decreases as size is reduced todiameter of 31.5 A; however, as CdS size further decreases, this trend is reversed and β valueincreases. Substantially, the normalized β value per CdS formula unit, β0, exhibits systematicenhancement with decreasing size. This phenomenon is interpreted in terms of a so-calledsurface contribution mechanism.
Fractal analysis of the Rayleigh Photoinduced Light Scattering Pattern from LiNbO3:Zn Crystals
Sidorov, N. V.; Manukovskaya, D. V.; Palatnikov, M. N.
2017-03-01
Fractal analysis was used to study Rayleigh photoinduced light scattering (PILS) patterns in a series of LiNbO3:Zn single crystals (0.018-0.88 mass%) that were grown from the congruent melt and were promising as nonlinear optical materials with low photorefraction and coercive-field values. Results from fractal analysis and Raman light-scattering spectroscopy were compared. Extremes found on the time dependence of the fractal dimension of various layers of the PILS pattern speckle structure indicated that the concentration of laser-induced defects in the photorefractive crystal changed. The rate of change of the concentration of laser-induced defects depended non-linearly on the crystal Zn concentration. The form of congruent Zn-doped LiNbO3 crystals with the most ordered structure was identified.
Xi Shao
2016-03-01
Full Text Available The Visible Infrared Imaging Radiometer Suite (VIIRS onboard Suomi National Polar Orbiting Partnership (SNPP uses a solar diffuser (SD as its radiometric calibrator for the reflective solar band calibration. The SD is made of Spectralon™ (one type of fluoropolymer and was chosen because of its controlled reflectance in the Visible/Near-Infrared/Shortwave-Infrared region and its near-Lambertian reflectance property. On-orbit changes in VIIRS SD reflectance as monitored by the Solar Diffuser Stability Monitor showed faster degradation of SD reflectance for 0.4 to 0.6 µm channels than the longer wavelength channels. Analysis of VIIRS SD reflectance data show that the spectral dependent degradation of SD reflectance in short wavelength can be explained with a SD Surface Roughness (length scale << wavelength based Rayleigh Scattering (SRRS model due to exposure to solar UV radiation and energetic particles. The characteristic length parameter of the SD surface roughness is derived from the long term reflectance data of the VIIRS SD and it changes at approximately the tens of nanometers level over the operational period of VIIRS. This estimated roughness length scale is consistent with the experimental result from radiation exposure of a fluoropolymer sample and validates the applicability of the Rayleigh scattering-based model. The model is also applicable to explaining the spectral dependent degradation of the SDs on other satellites. This novel approach allows us to better understand the physical processes of the SD degradation, and is complementary to previous mathematics based models.
Conti, C. C.; Anjos, M. J.; Salgado, C. M.
2014-09-01
X-ray fluorescence technique plays an important role in nondestructive analysis nowadays. The development of equipment, including portable ones, enables a wide assortment of possibilities for analysis of stable elements, even in trace concentrations. Nevertheless, despite of the advantages, one important drawback is radiation self-attenuation in the sample being measured, which needs to be considered in the calculation for the proper determination of elemental concentration. The mass attenuation coefficient can be determined by transmission measurement, but, in this case, the sample must be in slab shape geometry and demands two different setups and measurements. The Rayleigh to Compton scattering ratio, determined from the X-ray fluorescence spectrum, provides a link to the mass attenuation coefficient by means of a polynomial type equation. This work presents a way to construct a Rayleigh to Compton scattering ratio versus mass attenuation coefficient curve by using the MCNP5 Monte Carlo computer code. The comparison between the calculated and literature values of the mass attenuation coefficient for some known samples showed to be within 15%. This calculation procedure is available on-line at www.macx.net.br.
Thakkar, Disha; Gevriya, Bhavesh; Mashru, R. C.
2014-03-01
Linezolid reacted with palladium to form 1:1 binary cationic chelate which further reacted with eosin dye to form 1:1 ternary ion association complex at pH 4 of Walpole's acetate buffer in the presence of methyl cellulose. As a result not only absorption spectra were changed but Resonance Rayleigh Scattering (RRS), Second-order Scattering (SOS) and Frequency Doubling Scattering (FDS) intensities were greatly enhanced. The analytical wavelengths of RRS, SOS and FDS (λex/λem) of ternary complex were located at 538 nm/538 nm, 240 nm/480 nm and 660 nm/330 nm, respectively. The linearity range for RRS, SOS and FDS methods were 0.01-0.5 μg mL-1, 0.1-2 μg mL-1 and 0.2-1.8 μg mL-1, respectively. The sensitivity order of three methods was as RRS > SOS > FDS. Accuracy of all methods were determined by recovery studies and showed recovery between 98% and 102%. Intraday and inter day precision were checked for all methods and %RSD was found to be less than 2 for all methods. The effects of foreign substances were tested on RRS method and it showed the method had good selectivity. For optimization of process parameter, Taguchi orthogonal array design L8(24) was used and ANOVA was adopted to determine the statistically significant control factors that affect the scattering intensities of methods. The reaction mechanism, composition of ternary ion association complex and reasons for scattering intensity enhancement was discussed in this work.
Calculating Rayleigh scattering amplitudes from 100 eV to 10 MeV. [100 eV to 10 MeV
Parker, J.C.; Reynaud, G.W.; Botto, D.J.; Pratt, R.H.
1979-05-01
An attempt is made to explain how to calculate the contribution to elastic photon-atom scattering due to Rayleigh scattering (the scattering off bound electrons) in the photon energy range 100 eV less than or equal to W less than or equal to 10 MeV. All intermediate calculations are described, including the calculation of the potential, bound state wave functions, matrix elements, and final cross sections. 12 references. (JFP)
Liu, Zhengwen; Liu, Shaopu; Wang, Lei; Peng, Juanjuan; He, Youqiu
2009-09-01
In pH 6.6 Britton-Robinson buffer medium, the CdS quantum dots capped by thioglycolic acid could react with aminoglycoside (AGs) antibiotics such as neomycin sulfate (NEO) and streptomycin sulfate (STP) to form the large aggregates by virtue of electrostatic attraction and the hydrophobic force, which resulted in a great enhancement of resonance Rayleigh scattering (RRS) and resonance non-linear scattering such as second-order scattering (SOS) and frequency doubling scattering (FDS). The maximum scattering peak was located at 310 nm for RRS, 568 nm for SOS and 390 nm for FDS, respectively. The enhancements of scattering intensity (Δ I) were directly proportional to the concentration of AGs in a certain ranges. A new method for the determination of trace NEO and STP using CdS quantum dots probe was developed. The detection limits (3 σ) were 1.7 ng mL -1 (NEO) and 4.4 ng mL -1 (STP) by RRS method, were 5.2 ng mL -1 (NEO) and 20.9 ng mL -1 (STP) by SOS method and were 4.4 ng mL -1 (NEO) and 25.7 ng mL -1 (STP) by FDS method, respectively. The sensitivity of RRS method was the highest. The optimum conditions and influence factors were investigated. In addition, the reaction mechanism was discussed.
Collisional effects on Rayleigh-Taylor-induced magnetic fields
Manuel, M. J.-E. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Flaig, M.; Plewa, T. [Florida State University, Tallahassee, Florida 32306 (United States); Li, C. K.; Séguin, F. H.; Frenje, J. A.; Casey, D. T.; Petrasso, R. D. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hu, S. X.; Betti, R.; Hager, J.; Meyerhofer, D. D.; Smalyuk, V. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)
2015-05-15
Magnetic-field generation from the Rayleigh-Taylor (RT) instability was predicted more than 30 years ago, though experimental measurements of this phenomenon have only occurred in the past few years. These pioneering observations demonstrated that collisional effects are important to B-field evolution. To produce fields of a measurable strength, high-intensity lasers irradiate solid targets to generate the nonaligned temperature and density gradients required for B-field generation. The ablation process naturally generates an unstable system where RT-induced magnetic fields form. Field strengths inferred from monoenergetic-proton radiographs indicate that in the ablation region diffusive effects caused by finite plasma resistivity are not negligible. Results from the first proof-of-existence experiments are reviewed and the role of collisional effects on B-field evolution is discussed in detail.
无
2009-01-01
CdTe nanocrystals(CdTe NCs) were achieved by reaction of CdCl2 with KHTe solution and were capped with sodium mercaptoacetate.The product was detected by transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM),energy dispersive spectroscopy(EDS),fluorescence spectra,ultraviolet-visible spectra and X-ray diffraction(XRD).The CdTe NCs are of cubic structure and the average size is about 5 nm.The fluorescence quantum yield of CdTe NCs aqueous solution increased from 37% to 97% after 20 d under room light.The maximum λem of fluorescence changed from 543 nm to 510 nm and the blue shift was 33 nm.CdTe NCs aqueous solution can be steady for at least 10 months at 4℃ in a refrigerator.The resonance Rayleigh scattering(RRS) of CdTe NCs in the aqueous solution was investigated.The maximum scattering peak was located at about 554 nm.The interactions of CdTe NCs with amikacin sulfate(AS) and micronomicin sulfate(MS) were investigated respectively.The effects of AS and MS on fluorescence and RRS of CdTe NCs were analyzed.It was found that AS and MS quenched the photoluminescence of CdTe NCs and enhanced RRS of CdTe NCs.Under optimum conditions,there are linear relationships between quenching intensity(F0-F),intensity of RRS(I-I0) and concentration of AS and MS.The detection limits(3б) of AS and MS are respectively 3.4 ng·mL-1 and 2.6 ng·mL-1 by the fluorescence quenching method,and 15.2 ng·mL-1 and 14.0 ng·mL-1 by the RRS method.The methods have high sensitivity,thus CdTe NCs may be used as fluorescence probes and RRS probes for the detection of aminoglycoside antibiotics.
Qiao, Man; Wang, Yaqiong; Liu, Shaopu; Liu, Zhongfang; Yang, Jidong; Zhu, Jinghui; Hu, Xiaoli
2015-03-01
A new method based on resonance Rayleigh scattering (RRS) was proposed for the determination of quinolones (QNS) at the nanogram level. In pH 3.3-4.4 Britton-Robinson buffer medium, quinolones such as ciprofloxacin, pipemidic acid (PIP), lomefloxacin (LOM), norfloxacin (NOR) and sarafloxacin (SAR) were protonated and reacted with methyl orange (MO) to form an ion-pair complex, which then further formed a six-membered ring chelate with Pd(II). As a result, new RRS spectra appeared and the RRS intensities were enhanced greatly. RRS spectral characteristics of the MO-QNS-Pd(II) systems, the optimum conditions for the reaction, and the influencing factors were investigated. Under optimum conditions, the scattering intensity (∆I) increments were directly proportional to the concentration of QNS with in certain ranges. The method had high sensitivity, and the detection limits (3σ) ranged from 6.8 to 12.6 ng/mL. The proposed method had been successfully applied for the determination of QNS in pharmaceutical formulations and human urine samples. In addition, the mechanism of the reaction system was discussed based on IR, absorption and fluorescence spectral studies. The reasons for the enhancement of scattering spectra were discussed in terms of fluorescence-scattering resonance energy transfer, hydrophobicity and molecular size.
Yi Guobin; Zhu Zhenghong; Wang Fei; Chen Xudong; Yang Jin; Huang Yunwei
2011-01-01
A thermally sensitive copolymer, poly(N-isopropylacrylamfide-co-styrene) [P(NIPAM-co-St)] (Mn=9.5×105 g/mol and Mw/Mn= 1.51) was synthesized by soap-free emulsion polymerization. The phase separation of the co-polymer in water was investigated by Rayleigh scattering (RS) technique. The RS spectra revealed the transition of molecular conformation and the aggregation of molecular chains in the course of phase separation. The coil-to-globule and globule-to-coil transitions of P(NIPAM-co-St) chains were found in one heating-and-cooling cycle. By means of Avrami formula, apparent activation energy of phase separation of P(NIPAM-co-St) aqueous solutions was estimated. Moreover, a model was proposed to describe the phase separation process.
FAN,Li; LIU,Shao-Pu; YANG,Da-Cheng; LUO,Hong-Qun
2003-01-01
In acidic medium, thorium (Ⅳ) can react with a bisazo dye ofchromotropic acids such as arsenazo Ⅲ (AA Ⅲ), arsenazo M (AAM), chlorophosphonazo Ⅲ (CPA Ⅲ) and chlorosulphonphenol S (CSP S) to form an anionic chelate which further interacts with some proteins to produce a complex. This results in a significant enhancement of intensity of the resonance Rayleigh scattering (RRS) and the appearance of a new RRS spectrum. There are a few obvious RRS peaks in the range of 400-470 nm and the most intensive peak of them is lorated at 470 nm. The intensity of RRS is directly proportional to the concentration of protein in the range of tively. This new RRS method has high sensitivity and fairly good selectivity and can be applied to the direct determinstion of proteins in human serum with satisfactory results.
Wang, Qi; Huang, Xi; Fu, Xuan; Deng, Huan; Ma, Meihu; Cai, Zhaoxia
2016-06-05
Avidin is a glycoprotein with antinutritional property, which should be limited in daily food. We developed an affinity biosensor system based on resonance Rayleigh scattering (RRS) and using affinity biotin labeling Au nanoparticles (AuNPs). This method was selective and sensitive for quick avidin detection due to the avidin-biotin affinitive interaction. Under optimal conditions, RRS intensity of biotin-AuNPs increase linearly with an increasing concentration of avidin from 5 to 160 ng/mL. The lower limit of detection was 0.59 ng/mL. This rapid and selective avidin detection method was used in synthetic samples and egg products with recoveries of between 102.97 and 107.92%, thereby demonstrating the feasible and practical application of this assay. Copyright © 2016 Elsevier B.V. All rights reserved.
Dzierzega, K.; Mendys, A.; Zawadzki, W. [Marian Smoluchowski Institute of Physics, Jagiellonian University, ul. Reymonta 4, 30-059 Krakow (Poland); Pokrzywka, B. [Mt. Suhora Observatory, Pedagogical University of Cracow, ul. Podchorazych 2, 30-084 Krakow (Poland); Pellerin, S. [GREMI, site de Bourges, Universite d' Orleans, CNRS, rue Gaston Berger BP 4043, 18028 Bourges (France)
2013-04-01
Thomson and Rayleigh scattering methods were applied to quantify the electron and heavy particle temperatures, as well as electron number density, in a laser spark in helium at atmospheric pressure. Plasma was created using 4.5 ns, 25 mJ pulses from Nd:YAG laser at 532 nm. Measurements, performed for the time interval between 20 ns and 800 ns after breakdown, show electron density and temperature to decrease from 7.8 Multiplication-Sign 10{sup 23} m{sup -3} to 2.6 Multiplication-Sign 10{sup 22} m{sup -3} and from 95 900 K to 10 350 K, respectively. At the same time, the heavy particle temperature drops from only 47 000 K down to 4100 K which indicates a two temperature plasma out of local isothermal equilibrium.
Rayleigh scattering of Moessbauer radiation in superionic conductor RbAg/sub 4/I/sub 5/
Ovanesyan, N.S.; Goffman, V.G.; Sokolov, V.B.; Tkachev, V.V. (AN SSSR, Chernogolovka. Otdelenie Inst. Khimicheskoj Fiziki)
1984-04-01
The dynamical properties of RbAg/sub 4/I/sub 5/ has been investiaated by Rayleigh scattering of Moessbauer radiation (RSMR) with wave-length lambda = 0.86 A. The character of Ag/sup +/ ion oscillatory motion and diffusion in RbAg/sub 4/I/sub 5/ depending on temperature including the phase transitions region is studied. It is shown that in the superionic crystal RbAg/sub 4/I/sub 5/ the diffusion process is strongly correlated, i.e. a great number of initial and final states at diffusion jumps coincide. The observed broadening can be less than the expected one by value orders. Diffusion correlation can strongly reduce the activation barrier and lead to anomalously high ionic conduction.
Bi, Shuyun; Wang, Yu; Wang, Tianjiao; Pang, Bo; Zhao, Tingting
2013-01-15
A new sensitive DNA probe containing cetylpyridinium bromide (CPB) and emodin (an effective component of Chinese herbal medicine) was developed using the resonance Rayleigh light scattering (RLS) technique. A novel assay was first developed to detect DNA at nanogram level based on the ternary system of DNA-CPB-emodin. The RLS signal of DNA was enhanced remarkably in the presence of emodin-CPB, and the enhanced RLS intensity at 340.0 nm was in direct proportion to DNA concentration in the range of 0.01-2.72 μg mL(-1) with a good linear relationship. The detection limit was 1.5 ng mL(-1). Three synthetic DNA samples were measured obtaining satisfactory results, the recovery was 97.6-107.3%.
Cylindrical Effects on Magneto-Rayleigh-Taylor Instability
Weis, Matthew; Lau, Yue Ying; Gilgenbach, Ronald; Jennings, Christopher; Hess, Mark
2012-10-01
This paper concentrates on the effects of cylindrical geometry on the magneto-Rayleigh-Taylor instability (MRT), a major concern in the magnetized liner inertial fusion concept (MagLIF) [1]. Several issues are being studied, such as the Bell-Plesset effect [2], the effects of magnetic shear and feedthrough [3], and the nonzero MRT growth rate that remains (but was hardly noticed) in the k = m = 0 limit in Harris' seminal paper on a cylindrical liner [4], where k and m are respectively the azimuthal and axial wavenumber. We shall use simulation and direct integration of the eigenvalue equation to investigate the importance of the cylindrical geometry, which is particularly relevant in the final stage of compression in the MagLIF concept. [4pt] [1] S. A. Slutz, et. al, Phys. Plasmas 17, 056303 (2010). [0pt] [2] G. I. Bell, Los Alamos Scientific Laboratory, Report LA-1321 (1951); M. S. Plesset, J. Appl. Phys. 25, 96 (1954).[0pt] [3] P. Zhang et al., Phys. Plasmas 19, 200703 (2012); Y. Y. Lau et al., Phys. Rev. E 83, 006405 (2011). [0pt] [4] E. G. Harris, Phys. Fluids 5, 1057 (1962).
Kohei Arai
2013-08-01
Full Text Available Comparison of the rain rate estimated with the assumptions of Rayleigh and Mie scattering is made. We analyzed the different relationships between the radar reflective factor and rain rate (so-called Z-R relationship with both scattering models for different DSD (droplet size distribution and rainfall types as the wavelength is 2.2cm which is in accord with the band of TRMM/PR. Meanwhile we introduced a discrete ordinates method to retrieve the Z-R relationship for Mie scattering assumption. It is found that the retrieval result can be represented as the sum of some simple Z-R relationships. By the analysis of the Z-R relationships estimated from Rayleigh and Mie scattering assumptions in the rain types, we found that the difference of Z-R relationships between Rayleigh and Mie scattering in the thunderstorm that represents the larger raindrop size is larger than that in the drizzle that represent the smaller raindrop size.
Reynolds and Atwood Numbers Effects on Homogeneous Rayleigh Taylor Instability
Aslangil, Denis; Livescu, Daniel; Banerjee, Arindam
2015-11-01
The effects of Reynolds and Atwood numbers on turbulent mixing of a heterogeneous mixture of two incompressible, miscible fluids with different densities are investigated by using high-resolution Direct Numerical Simulations (DNS). The flow occurs in a triply periodic 3D domain, with the two fluids initially segregated in random patches, and turbulence is generated in response to buoyancy. In turn, stirring produced by turbulence breaks down the scalar structures, accelerating the molecular mixing. Statistically homogeneous variable-density (VD) mixing, with density variations due to compositional changes, is a basic mixing problem and aims to mimic the core of the mixing layer of acceleration driven Rayleigh Taylor Instability (RTI). We present results covering a large range of kinematic viscosity values for density contrasts including small (A =0.04), moderate (A =0.5), and high (A =0.75 and 0.9) Atwood numbers. Particular interest will be given to the structure of the turbulence and mixing process, including the alignment between various turbulence and scalar quantities, as well as providing fidelity data for verification and validation of mix models. Arindam Banerjee acknowledges support from NSF CAREER award # 1453056.
Motion Induced by Light: Photokinetic Effects in the Rayleigh Limit
Ruffner, David B; Grier, David G
2015-01-01
Structured beams of light can move small objects in surprising ways. Particularly striking examples include observations of polarization-dependent forces acting on optically isotropic objects and tractor beams that can pull objects opposite to the direction of the light's propagation. Here we develop a theoretical framework in which these effects vanish at the leading order of light scattering theory. Exotic optical forces emerge instead from interference between different orders of multipole scattering. These effects create a rich variety of ways to manipulate small objects with light, so-called photokinetic effects. Applying this formalism to the particular case of Bessel beams offers useful insights into the nature of tractor beams and the interplay between spin and orbital angular momentum in vector beams of light, including a manifestation of orbital-to-spin conversion.
Collision-induced hyper-Rayleigh light scattering in gaseous dihydrogen-neon mixtures
Glaz, W.; Bancewicz, T. [Nonlinear Optics Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, PL-61-614 Poznan (Poland); Godet, J.-L. [Laboratoire de Photonique d' Angers, EA 4464, Universite d' Angers, 2 boulevard Lavoisier, F-49045 Angers Cedex 01 (France); Haskopoulos, A.; Maroulis, G. [Department of Chemistry, University of Patras, GR-26500 Patras (Greece)
2011-07-15
Cartesian components of the collision-induced (CI) hyperpolarizability {Delta}{beta} tensor are computed for the linear, T-shaped, and 45 deg. configurations of the H{sub 2}-Ne pair in the intermolecular range 3 to 14 bohr. Symmetry-adapted components {Delta}{beta}{sub {lambda}L}{sup (K)}(R) of the vector (K=1) part, as well as the septor (K=3) part, of the H{sub 2}-Ne CI hyperpolarizability are calculated starting from the ab initio Cartesian hyperpolarizability tensor values transformed into their spherical counterparts. By applying these quantities, the vector together with the septor collision-induced hyper-Rayleigh (CIHR) spectra for the H{sub 2}-Ne binary gas mixture are determined in the frequency range from -1250 to 2500 cm{sup -1}. The profiles are partially employed as a benchmarking device to estimate the importance of the short intermolecular distance part of the {Delta}{beta}(R) dependence. The depolarization ratio of the CIHR spectra in the whole frequency range is also calculated. The nature of the CIHR signal and the feasibility of the related experiments are discussed and analyzed.
Rother, Tom
2016-07-01
In this paper I propose a classical optics experiment that results in a maximum violation of a Bell-like inequality. The first part is concerned with the Bell-like inequality (the so-called CHSH-inequality) itself. Its importance and its maximum violation in Quantum Mechanics (QM) are discussed in detail by employing an abstract probability state concept in a 4-dim. but classical event space. A T-matrix that represents the integral part of a corresponding Green's function as well as a statistical operator that contains a negative quasi-probability can be related to the corresponding quantum mechanical experiment. It is demonstrated that the derivation and usage of the T-matrix and the Green's function is equivalent to what is known from classical scattering theory. It is shown moreover that the negative quasi-probability of the statistical operator may be interpreted as a sink of probabilities related to two single events of the considered 4-dim. event space. A necessary condition for the violation of the CHSH-inequality is derived and discussed afterwards. In the second part of this paper I discuss a modification of the 4-dim. event space considered in the first part. It is shown that a combination of conventional Rayleigh scattering with a Mach-Zehnder setup would be able to put this modification into practice. Thus it becomes possible to achieve a maximum violation of the CHSH-inequality, if formulated in terms of intensities, on a pure classical way. The combination of classical light scattering with correlation experiments such as proposed in this paper may open new ways to study and to use the violation of Bell-like inequalities in modern optics.
Hödemann, S.; Möls, P.; Kiisk, V.; Murata, T.; Saar, R.; Kikas, J.
2015-12-01
A new optical method is presented for evaluation of the stress profile in chemically tempered (chemically strengthened) glass based on confocal detection of scattered laser beam. Theoretically, a lateral resolution of 0.2 μm and a depth resolution of 0.6 μm could be achieved by using a confocal microscope with high-NA immersion objective. The stress profile in the 250 μm thick surface layer of chemically tempered lithium aluminosilicate glass was measured with a high spatial resolution to illustrate the capability of the method. The confocal method is validated using transmission photoelastic and Na+ ion concentration profile measurement. Compositional influence on the stress-optic coefficient is calculated and discussed. Our method opens up new possibilities for three-dimensional scattered light tomography of mechanical imaging in birefringent materials.
Hödemann, S., E-mail: siim.hodemann@ut.ee; Möls, P.; Kiisk, V.; Saar, R.; Kikas, J. [Institute of Physics, University of Tartu, Wilhelm Ostwald st., Tartu 50411 (Estonia); Murata, T. [Nippon Electric Glass Co., 7-1 Seiran 2-chome, Otsu-shi, Shiga 520-8639 (Japan)
2015-12-28
A new optical method is presented for evaluation of the stress profile in chemically tempered (chemically strengthened) glass based on confocal detection of scattered laser beam. Theoretically, a lateral resolution of 0.2 μm and a depth resolution of 0.6 μm could be achieved by using a confocal microscope with high-NA immersion objective. The stress profile in the 250 μm thick surface layer of chemically tempered lithium aluminosilicate glass was measured with a high spatial resolution to illustrate the capability of the method. The confocal method is validated using transmission photoelastic and Na{sup +} ion concentration profile measurement. Compositional influence on the stress-optic coefficient is calculated and discussed. Our method opens up new possibilities for three-dimensional scattered light tomography of mechanical imaging in birefringent materials.
Semi-classical Dynamics of Superradiant Rayleigh Scattering in a Bose-Einstein Condensate
Müller, J H; Targat, R le; Arlt, J J; Polzik, E S; Hilliard, A J
2016-01-01
Due to its coherence properties and high optical depth, a Bose-Einstein condensate provides an ideal setting to investigate collective atom-light interactions. Superradiant light scattering in a Bose-Einstein condensate is a fascinating example of such an interaction. It is an analogous process to Dicke superradiance, in which an electronically inverted sample decays collectively, leading to the emission of one or more light pulses in a well-defined direction. Through time-resolved measurements of the superradiant light pulses emitted by an end-pumped BEC, we study the close connection of superradiant light scattering with Dicke superradiance. A 1D model of the system yields good agreement with the experimental data and shows that the dynamics results from the structures that build up in the light and matter-wave fields along the BEC. This paves the way for exploiting the atom-photon correlations generated by the superradiance.
Rayleigh Scattering Cross Section Redward of Ly$\\alpha$ by Atomic Hydrogen
Lee, Hee-Won; Kim, Hee Il
2004-01-01
We present a low energy expansion of the Kramers-Heisenberg formula for atomic hydrogen in terms of $(\\omega/\\omega_l)$, where $\\omega_l$ and $\\omega$ are the angular frequencies corresponding to the Lyman limit and the incident radiation, respectively. The leading term is proportional to $(\\omega/\\omega_l)^4$, which admits a well-known classical interpretation. With higher order terms we achieve accuracy with errors less than 4 % of the scattering cross sections in the region $\\omega/\\omega_...
LIU; Shaopu(刘绍璞); HU; Xiaoli(胡小莉); LUO; Hongqun(罗红群); FAN; Li(范莉)
2002-01-01
In near neutral medium, the resonance Rayleigh scattering (RRS) intensities of an alone cationic surfactant and nucleic acid are very weak. However, when they combine with each other to form a complex, the RRS intensity of the solution is enhanced greatly. In this paper the reactions of five cationic surfactants with nucleic acids have been studied. The results show that the reaction conditions and RRS spectral characteristics of these reactions are similar, but their sensitivities are obviously different. Among them, the sensitivity of cetyldimethyl benzylammonium chloride (CDBAC) with an aryl and large molecular weight is the highest, while that of cetyltrimethylammonium bromide (CTAB) without aryl and with small molecular weight is the lowest. The detection limits for ctDNA and yRNA of the former are 6.6 and 29.4 ng@mL?1, while that of the latter are 13.3 and 53.6 ng@mL?1. The method has better selectivity and can be applied to the determination of trace amounts of nucleic acids. Furthermore, it is discovered in the investigation that not only the RRS intensity is related to the structure and molecular weight of the cationic surfactants, but also the change of the RRS intensity is closely related to the conformational change of nucleic acid. Therefore, the RRS method can be expanded to become a useful way to study the nucleic acid conformation.
无
2010-01-01
The forming of bleomycinA2-Cu(Ⅱ) cationic chelate and the interaction of the chelate with DNA have been investigated by using resonance Rayleigh scattering(RRS),molecular absorption and fluorescence spectra.The result shows that in aqueous solution,bleomycinA2(BLMA2) can react with Cu(Ⅱ) to form 1:1 cationic chelate which contributes to the changes of the absorption spectra and the quenched fluorescence of BLMA2.When the cationic chelate further bound with DNA to form ternary ion-association complexes,the remarkable enhancement of the RRS intensity was observed.In this work,the optimum conditions for the coordination reaction of BLMA2 with Cu(Ⅱ) and some influencing factors have been investigated.The reaction mechanism of BLMA2-Cu(Ⅱ) binding with DNA was suggested and a binding model was proposed.In addition,the fluorescence quenching type of BLMA2 was investigated.A highly sensitive,simple and rapid new method for the determination of DNA by using BLMA2-Cu(Ⅱ) as RRS probe has been developed.The detection limits(3σ) are 7.2 ng/mL for ctDNA,7.1 ng/mL for sDNA and 18 ng/mL for hsDNA.The method can be applied to the determination of trace amounts of DNA.
Casamayou-Boucau, Yannick; Ryder, Alan G.
2017-09-01
Anisotropy resolved multidimensional emission spectroscopy (ARMES) provides valuable insights into multi-fluorophore proteins (Groza et al 2015 Anal. Chim. Acta 886 133-42). Fluorescence anisotropy adds to the multidimensional fluorescence dataset information about the physical size of the fluorophores and/or the rigidity of the surrounding micro-environment. The first ARMES studies used standard thin film polarizers (TFP) that had negligible transmission between 250 and 290 nm, preventing accurate measurement of intrinsic protein fluorescence from tyrosine and tryptophan. Replacing TFP with pairs of broadband wire grid polarizers enabled standard fluorescence spectrometers to accurately measure anisotropies between 250 and 300 nm, which was validated with solutions of perylene in the UV and Erythrosin B and Phloxine B in the visible. In all cases, anisotropies were accurate to better than ±1% when compared to literature measurements made with Glan Thompson or TFP polarizers. Better dual wire grid polarizer UV transmittance and the use of excitation-emission matrix measurements for ARMES required complete Rayleigh scatter elimination. This was achieved by chemometric modelling rather than classical interpolation, which enabled the acquisition of pure anisotropy patterns over wider spectral ranges. In combination, these three improvements permit the accurate implementation of ARMES for studying intrinsic protein fluorescence.
Long, Xiufen; Zhang, Caihua; Cheng, Jiongjia; Bi, Shuping
2008-01-01
We present a novel method for the study of the aggregation of protein induced by metal ion aluminum(III) using resonance Rayleigh scattering (RRS) technique. In neutral Tris-HCl medium, the effect of this aggregation of protein results in the enhancement of RRS intensity and the relationship between the enhancement of the RRS signal and the Al concentration is nonlinear. On this basis, we established a new method for the determination of the critical induced-aggregation concentrations ( CCIAC) of metal ion Al(III) inducing the protein aggregation. Our results show that many factors, such as, pH value, anions, salts, temperature and solvents have obvious effects. We also studied the extent of aggregation and structural changes using ultra-violet spectrometry, protein intrinsic fluorescence and circular dichroism to further understand the exact mechanisms of the aggregation characteristics of proteins induced by metal ion Al(III) at the molecular level, to help us to develop effective methods to investigate the toxicity of metal ion Al, and to provide theoretical and quantitative evidences for the development of appropriate treatments for neurodementia such as Parkinson's disease, Alzheimer's disease and dementia related to dialysis.
无
2010-01-01
In a weak acidic medium(pH 2.4-2.8),eosin Y molecules(H2L) could replace water molecules to associate with Triton X-100 to form hydrophobic hydrogen bonding complexes.These complexes could further aggregate to form nanoparticles through the squeezing action of the water phase and Van Der Waals force,resulting in changes in the absorption spectrum and fluorescence quenching of EY as well as the significant enhancement of resonance Rayleigh scattering.This enables the sensitive determination of Triton X-100 using the fading spectrophotometry,fluorescence quenching method and RRS method.Among them,the RRS method shows the highest sensitivity with a detection limit of 20.6 ng mL-1 for Triton X-100.The optimum experimental conditions and factors that affect the absorption,fluorescence and RRS spectra were tested.The effects of coexisting substances were investigated and the results showed good selectivity.Based on these results,new spectrophotometric methods,fluorescence quenching method and RRS method for the determination of Triton X-100,were established.The hydrogen bonding association of eosin Y with Triton X-100 and the formation of nanoparticles as well as their effects on related spectral characteristics were discussed utilizing infrared,transmission electron microscope technique and quantum chemical method.
LIU; JiangTao; LIU; ZhongFang; LIU; ShaoPu
2007-01-01
The interaction of bleomycinA5 with nucleic acids has been investigated by using resonance Rayleigh scattering (RRS), molecular absorption and fluorescence spectra. The result shows that in near pH 2.2 buffer medium and absence of any metal ions, nucleic acids are capable of binding with bleomycinA5 (BLMA5) to form complexes which can remarkably enhance the RRS intensity and result in bathochromic and hyperchromic molecular absorption of nucleic acids and fluorescence quenching of bleomycinA5. The RRS spectral characteristics for the binding products of bleomycinA5 with various DNA and RNA are similar, and the maximum RRS peaks are at 301 nm for ctDNA and sDNA, 370 nm for hsDNA, 310 nm for RNAtypeVI and RNAtypeIII, respectively. The increments of RRS intensity are greatly different in which DNA enhances greatly and RNA enhances lightly. In this work, the optimum conditions of the interaction and some influencing factors have been investigated. The reaction mechanism and a binding model for the interaction of BLMA5 with the nucleic acids are discussed. In addition, a highly sensitive, simple and rapid new method for the determination of DNA has been developed. The detection limits (3σ) are 5.7 ng/mL for ctDNA, 7.4 ng/mL for sDNA and 9.2 ng/mL for hsDNA, respectively. The method can be applied to determination of trace amounts of DNA.
Sidewall effects in Rayleigh-B\\'enard convection
Stevens, Richard J A M; Verzicco, Roberto
2014-01-01
We investigate the influence of the temperature boundary conditions at the sidewall on the heat transport in Rayleigh-B\\'enard (RB) convection using direct numerical simulations. For relatively low Rayleigh numbers Ra the heat transport is higher when the sidewall is isothermal, kept at a temperature $T_c+\\Delta/2$ (where $\\Delta$ is the temperature difference between the horizontal plates and $T_c$ the temperature of the cold plate), than when the sidewall is adiabatic. The reason is that in the former case part of the heat current avoids the thermal resistance of the fluid layer by escaping through the sidewall that acts as a short-circuit. For higher Ra the bulk becomes more isothermal and this reduces the heat current through the sidewall. Therefore the heat flux in a cell with an isothermal sidewall converges to the value obtained with an adiabatic sidewall for high enough Ra ($\\simeq 10^{10}$). However, when the sidewall temperature deviates from $T_c+\\Delta/2$ the heat transport at the bottom and top p...
The acoustoelastic effect on Rayleigh waves in elastic-plastic deformed layered rocks
Liu Jin-Xia; Cui Zhi-Wen; Wang Ke-Xie
2007-01-01
On the basis of the acoustoelastic theory for elastic-plastic materials, the influence of statically deformed states including both the elastic and plastic deformations induced by applied uniaxial stresses on the Rayleigh wave in layered rocks is investigated by using a transfer matrix method. The acoustoelastic effects of elastic-plastic strains in rocks caused by static deformations, are discussed in detail. The Rayleigh-type and Sezawa modes exhibit similar trends in acoustoelastic effect: the acoustoelastic effect increasing rapidly with the frequency-thickness product and the phase velocity change approaching a constant value for thick layer and high frequency limit. Elastic-plastic deformations in the Castlegate layered rock obviously modify the phase velocity of the Rayleigh wave and the cutoff points for the Sezawa modes. The investigation may be useful for seismic exploration, geotechnical engineering and ultrasonic detection.
Ultraviolet Rayleigh Scatter Imaging for Spatial Temperature Profiles in Atmospheric Microdischarges
2014-09-01
is known as the Townsend breakdown, and is usually initiated by a cosmic ray for its first ionization [17]. The relationship between breakdown...electrodes. Here the current may be expressed as = 2, where is the effective radius and is the current density, which gives...For this case, the surrounding gas can be treated as a cooling shell and ℎ can be written as a function of our effective radius
PENG; Jingdong; LIU; Shaopu; LIU; Zhongfang; SHI; Yan
2006-01-01
In a pH 3.6-5.0 Hac-NaAc buffer solution, when sodium tanshinon ⅡA silate (STSⅡA) reacts with La(Ⅲ) to form a chelate, the resonance Rayleigh scattering (RRS) intensity can be enhanced greatly and a new RRS spectrum will appear. The maximum RRS peak is located at 306 nm and the RRS intensity is proportional to the concentration of STSⅡA in a certain range. The method is very sensitive and the detection limit for STSⅡA (3σ/K) is 82.12 ng·mL-1. The optimum reaction conditions and the effect of coexisting substances have been investigated. A new, simple and fast method for the determination of STSⅡA based on RRS method is developed. It can be applied to the determination of STSⅡA in the synthesis samples and Nuoxinkang injection. Combined with infrared absorption and NMR spectra, the structure of the chelate and the reasons of RRS enhancement are also discussed.
Bi, Shuyun; Wang, Yu; Pang, Bo; Yan, Lili; Wang, Tianjiao
2012-05-01
Two new systems for measuring DNA at nanogram levels by a resonance Rayleigh light scattering (RLS) technique with a common spectrofluorometer were proposed. In the presence of cetyltrimethylammonium bromide (CTAB), the interaction of DNA with hesperetin and apigenin (two effective components of Chinese herbal medicine) could enhance RLS signals with the maximum peak at 363 and 433 nm respectively. The enhanced intensity of RLS was directly proportional to the concentration of DNA in the range of 0.022-4.4 μg mL-1 for DNA-CTAB-hesperetin system and 0.013-4.4 μg mL-1 for DNA-CTAB-apigenin system. The detection limit was 2.34 ng mL-1 and 2.97 ng mL-1 respectively. Synthetic samples were measured satisfactorily. The recovery of DNA-CTAB-hesperetin system was 97.3-101.9% and that of DNA-CTAB-apigenin system was 101.2-109.5%.
Tsui, Po-Hsiang; Wan, Yung-Liang; Tai, Dar-In; Shu, Yu-Chen
2015-08-01
Ultrasound Nakagami imaging has recently attracted interest as an imaging technique for analyzing envelope statistics. Because the presence of structures has a strong effect on estimation of the Nakagami parameter, previous studies have indicated that Nakagami imaging should be used specifically for characterization of soft tissues with fewer structures, such as liver tissues. Typically, changes in the properties of the liver parenchyma cause the backscattered statistics to transform from a Rayleigh distribution to a pre-Rayleigh distribution, and this transformation can be visualized using a Nakagami imaging technique. However, different estimators result in different estimated values; thus, the performance of a Nakagami image may depend on the type of estimator used. This study explored the effects of various estimators on ultrasound Nakagami imaging to describe the backscattered statistics as they change from a Rayleigh distribution to a pre-Rayleigh distribution. Simulations and clinical measurements involving patients with liver fibrosis (n = 85) yielded image data that were used to construct B-mode and conventional Nakagami images based on the moment estimator (denoted as mINV images) and maximum-likelihood estimator (denoted as mML images). In addition, novel window-modulated compounding Nakagami images based on the moment estimator (denoted as mWMC images) were also obtained. The means and standard deviations of the Nakagami parameters were examined as a function of the backscattered statistics. The experimental results indicate that the mINV, mML and mWMC images enabled quantitative visualization of the change in backscattered statistics from a Rayleigh distribution to a pre-Rayleigh distribution. Importantly, the mWMC image is superior to both mINV and mML images because it simultaneously realizes sensitive detection of the backscattered statistics and a reduction of estimation variance for image smoothness improvement. We therefore recommend using m
Cloaking of solar cell contacts at the onset of Rayleigh scattering
San Román, Etor; Vitrey, Alan; Buencuerpo, Jerónimo; Prieto, Iván; Llorens, José M.; García-Martín, Antonio; Alén, Benito; Chaudhuri, Anabil; Neumann, Alexander; Brueck, S. R. J.; Ripalda, José M.
2016-01-01
Electrical contacts on the top surface of solar cells and light emitting diodes cause shadow losses. The phenomenon of extraordinary optical transmission through arrays of subwavelength holes suggests the possibility of engineering such contacts to reduce the shadow using plasmonics, but resonance effects occur only at specific wavelengths. Here we describe instead a broadband effect of enhanced light transmission through arrays of subwavelength metallic wires, due to the fact that, in the absence of resonances, metal wires asymptotically tend to invisibility in the small size limit regardless of the fraction of the device area taken up by the contacts. The effect occurs for wires more than an order of magnitude thicker than the transparency limit for metal thin films. Finite difference in time domain calculations predict that it is possible to have high cloaking efficiencies in a broadband wavelength range, and we experimentally demonstrate contact shadow losses less than half of the geometric shadow. PMID:27339390
Siewe, M. Siewe [Laboratoire de Mecanique, Departement de Physique, Faculte des sciences, Universite de Yaounde I, B.P. 812 Yaounde (Cameroon); Cao, Hongjun [Department of Mathematics, School of Science, Beijing Jiaotong University, Beijing 100044 (China); Nonlinear Dynamics and Chaos Group, Departamento de Fisica, Universidad Rey Juan Carlos, Tulipan s/n, 28933 Mostoles, Madrid (Spain); Sanjuan, Miguel A.F. [Nonlinear Dynamics and Chaos Group, Departamento de Fisica, Universidad Rey Juan Carlos, Tulipan s/n, 28933 Mostoles, Madrid (Spain)], E-mail: miguel.sanjuan@urjc.es
2009-02-15
The Rayleigh oscillator is one canonical example of self-excited systems. However, simple generalizations of such systems, such as the Rayleigh-Duffing oscillator, have not received much attention. The presence of a cubic term makes the Rayleigh-Duffing oscillator a more complex and interesting case to analyze. In this work, we use analytical techniques such as the Melnikov theory, to obtain the threshold condition for the occurrence of Smale-horseshoe type chaos in the Rayleigh-Duffing oscillator. Moreover, we examine carefully the phase space of initial conditions in order to analyze the effect of the nonlinear damping, and in particular how the basin boundaries become fractalized.
Mielke, Amy F.; Elam, Kristie A.; Sung, Chih-Jen
2007-01-01
A molecular Rayleigh scattering technique is developed to measure time-resolved gas velocity, temperature, and density in unseeded turbulent flows at sampling rates up to 32 kHz. A high power continuous-wave laser beam is focused at a point in an air flow field and Rayleigh scattered light is collected and fiber-optically transmitted to the spectral analysis and detection equipment. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. Photomultiplier tubes operated in the photon counting mode allow high frequency sampling of the circular interference pattern to provide time-resolved flow property measurements. An acoustically driven nozzle flow is studied to validate velocity fluctuation measurements, and an asymmetric oscillating counterflow with unequal enthalpies is studied to validate the measurement of temperature fluctuations. Velocity fluctuations are compared with constant temperature anemometry measurements and temperature fluctuations are compared with constant current anemometry measurements at the same locations. Time-series and power spectra of the temperature and velocity measurements are presented. A numerical simulation of the light scattering and detection process was developed and compared with experimental data for future use as an experiment design tool.
Chen, Fang; Peng, Jingdong; Liu, Shaopu; Peng, Huanjun; Pan, Ziyu; Bu, Lingli; Xiao, Huan; Zhang, Ruiwen
2017-04-01
A highly sensitive detection approach of resonance Rayleigh scattering spectra (RRS) is firstly applied to analyzing nootropic drugs including piracetam (PIR) and oxiracetam (OXI). In HCl-NaAc buffer solution (pH = 3.0), the OXI chelated with palladium (II) to form the chelate cation [Pd2·OXI]2 +, and then reacted with Congo red (CGR) by virtue of electrostatic attraction and hydrophobic force to form binary complex [Pd2·OXI]. CGR2, which could result in the great enhancement of RRS. The resonance Rayleigh scattering signal was recorded at λex = λem = 375 nm. This mixture complex not only has higher RRS, but also makes contribution to significant increase of fluorescence, and the same phenomena also were discovered in PIR. The enhanced RRS intensity is in proportion to the PIR and OXI concentration in the range of 0.03-3.0 μg mL- 1, and the detection limit (DL) of RRS method for PIR and OXI is 2.3 ng mL- 1 and 9.7 ng mL- 1. In addition, the DL of fluorescence method for PIR and OXI is 8.4 μg mL- 1 and 19.5 μg mL- 1. Obviously, the RRS is the highly sensitive method, and the recoveries of the two kinds of nootropic drugs were range from 100.4% to 101.8.0% with RSD (n = 5) from 1.1% to 3.1% by RRS method. This paper not only investigated the optimum conditions for detecting nootropics with using RRS method, but also focused on the reasons for enhancing RRS intensity and the reaction mechanism, which in order to firm and contract the resultant. Finally, The RRS method has been applied to detect nootropic drugs in human urine samples with satisfactory results. Fig. S2. The effect of ionic strength: Pd (II)-CGR system (curve a); Pd (II)-OXI-CGR system (curve b); Pd (II)-PIR- CGR system (curve c). Pd (II): 2.0 × 10- 4 mol L- 1; CGR: 1.0 × 10- 5 mol L- 1; OXI: 1.5 μg mL- 1; PIR: 2 μg mL- 1; NaCl: 1 mol L- 1. Fig. S3. The effect of time: Pd (II)-OXI-CGR system (curve a); Pd (II)-PIR-CGR system (curve b). Pd (II): 2.0 × 10- 4 mol L- 1; CGR: 1.0 × 10- 5 mol L- 1
Rayleigh imaging in spectral mammography
Berggren, Karl; Danielsson, Mats; Fredenberg, Erik
2016-03-01
Spectral imaging is the acquisition of multiple images of an object at different energy spectra. In mammography, dual-energy imaging (spectral imaging with two energy levels) has been investigated for several applications, in particular material decomposition, which allows for quantitative analysis of breast composition and quantitative contrast-enhanced imaging. Material decomposition with dual-energy imaging is based on the assumption that there are two dominant photon interaction effects that determine linear attenuation: the photoelectric effect and Compton scattering. This assumption limits the number of basis materials, i.e. the number of materials that are possible to differentiate between, to two. However, Rayleigh scattering may account for more than 10% of the linear attenuation in the mammography energy range. In this work, we show that a modified version of a scanning multi-slit spectral photon-counting mammography system is able to acquire three images at different spectra and can be used for triple-energy imaging. We further show that triple-energy imaging in combination with the efficient scatter rejection of the system enables measurement of Rayleigh scattering, which adds an additional energy dependency to the linear attenuation and enables material decomposition with three basis materials. Three available basis materials have the potential to improve virtually all applications of spectral imaging.
Mitigation Effect of Finite Larmor Radius on Rayleigh-Taylor Instability in Z-Pinch Implosions
邱孝明; 黄林; 简广德
2002-01-01
Based on the framework of magnetohydrodynamic theory, a simple model is proposed to study the mitigation effect of finite Larmor radius on the Rayleigh-Taylor instability in Z-pinch implosions. In this model, taking account of Ti ≥ Te in Z-pinch implosions we believe that the magnetohydrodynamic plasma responds to a perturbation (～ exp [i (k. x - ωt)]) at frequency (ω + ik2⊥ρ2iΩi) instead of frequency ω, where k2⊥ρ2i is due to the finite Larmor radius effects expressed from the generalkinetic theory of magnetized plasma. Therefore the linearized continuity and momentum equations for the perturbed mass-density and velocity include the finite Larmor radius effects. The calculations indicate that, in the wavenumber region of interest, the finite Larmor radius effects can mitigate the Rayleigh-Taylor instability in Z-pinch implosions.
Singh, Prem; Mehta, D.; Singh, N. E-mail: nsingh@pu.ac.in; Puri, S.; Shahi, J.S
2004-09-01
The K-L and K-M resonant Raman scattering (RRS) cross-sections have been measured for the first time at the 59.536 keV photon energy in the {sub 70}Yb (B{sub K}=61.332 keV), {sub 71}Lu (B{sub K}=63.316 keV) and {sub 72}Hf (B{sub K}=65.345 keV) elements; B{sub K} being the K-shell binding energy. The K-L and K-M RRS measurements have been performed at the 59 deg. and 133 deg. angles, respectively, to avoid interference of the Compton-scatter peak. The Rayleigh and Compton scattering cross-sections for the 59.536 keV {gamma}-rays have also been measured at both the angles in the atomic region 1{<=}Z{<=}92. Measurements were performed using the reflection-mode geometrical arrangements involving the {sup 241}Am radioisotope as photon source and planar Si(Li) and HPGe detectors. Ratios of the K-M and K-L RRS cross-sections in Yb, Lu and Hf are in general lower than that of the fluorescent K{beta}{sub 1,3,5} (K-M) and K{alpha} (K-L) X-ray transition probabilities. Theoretical Rayleigh scattering cross-sections based on the modified form-factors (MFs) corrected for the anomalous scattering factors (ASFs) and the S-matrix calculations are on an average {approx}15% and {approx}6% higher, respectively, at the 133 deg. angle and exhibit good agreement with the measured data at the 59 deg. angle. Larger deviations {approx}30% and {approx}20%, respectively, are observed at the 133 deg. angle for the {sub 64}Gd, {sub 66}Dy, {sub 67}Ho and {sub 70}Yb elements having the K-shell binding energy in vicinity of the incident photon energy. The measured Compton scattering cross-sections are in general agreement with those calculated using the Klein-Nishina cross-sections and the incoherent scattering function.
Effective potential for relativistic scattering
Elbistan, Mahmut; Balog, Janos
2016-01-01
We consider quantum inverse scattering with singular potentials and calculate the Sine-Gordon model effective potential in the laboratory and centre-of-mass frames. The effective potentials are frame dependent but closely resemble the zero-momentum potential of the equivalent Ruijsenaars-Schneider model.
Banquet Speech Some Sketches Of Rayleigh
Howard, John N.
1985-11-01
Several short sketches are presented of Lord Rayleigh, to show his method of working and his interaction with his fellow scientists. The topics discussed are: his research on the blue of the sky (Rayleigh scattering); his rescue of Waterston from near-oblivion; his research on surface acoustic waves (Rayleigh waves); his collaboration with Agnes Pockels; his research on blackbody radiation (the Rayleigh-Jeans Law).
Antoniassi, M.; Conceição, A. L. C.; Poletti, M. E.
2011-10-01
In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90° ( x=0.99 Å -1). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number ( Zeff) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Zeff of breast tissues, which are mainly related to the elemental composition of carbon ( Z=6) and oxygen ( Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.
Antoniassi, M.; Conceicao, A.L.C. [Departamento de Fisica e Matematica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil); Poletti, M.E., E-mail: poletti@ffclrp.usp.br [Departamento de Fisica e Matematica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil)
2011-10-01
In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90{sup o} (x=0.99 A{sup -1}). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number (Z{sub eff}) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Z{sub eff} of breast tissues, which are mainly related to the elemental composition of carbon (Z=6) and oxygen (Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.
Local Effects on Strain Seismograms at Matsushiro Seismological Observatory - 2. Rayleigh Waves
Taishi Okamoto
2007-01-01
Full Text Available We evaluate local effects on strain seismograms for a Rayleigh wave observed at Matsushiro Seismological Observatory, Japan Meteorological Agency, central Japan, by applying a method proposed in a previous report (Okamoto et al. 2007. The method involves examination of polarization angles, local phase velocity, and accuracy of velocity seismograms. The results are as follows: 1 Polarization angles of observed strain seismograms agree with expected ones from those of velocity seismograms also observed at Matsushiro; 2 Local phase velocity estimated by comparison between strain and velocity seismograms is 54% larger than the theoretical value calculated from the PREM velocity model; 3 Velocity spectra observed at Matsushiro have almost the same amplitude as an average of those at F-net observation stations near Matsushiro. These results indicate that both EW and NS component strain seismograms observed at Matsushiro have been reduced by 35% in amplitude for a Rayleigh wave due to local heterogeneity. The local effects on a Rayleigh wave are quite different from that on a Love wave obtained in the previous report.
Angerhausen, Daniel; Mandell, Avi; Dunham, Edward W; Becklin, Eric E; Collins, Peter L; Hamilton, Ryan T; Logsdon, Sarah E; McElwain, Michael W; McLean, Ian S; Pfueller, Enrico; Savage, Maureen L; Shenoy, Sachindev S; Vacca, William; VanCleve, Jeffry; Wolf, Juergen
2015-01-01
Here we report on the first successful exoplanet transit observation with the Stratospheric Observatory for Infrared Astronomy (SOFIA). We observed a single transit of the hot Jupiter HD 189733 b, obtaining two simultaneous primary transit lightcurves in the B and z' bands as a demonstration of SOFIA's capability to perform absolute transit photometry. We present a detailed description of our data reduction, in particular the correlation of photometric systematics with various in-flight parameters unique to the airborne observing environment. The derived transit depths at B and z' wavelengths confirm a previously reported slope in the optical transmission spectrum of HD 189733 b. Our results give new insights to the current discussion about the source of this Rayleigh scattering in the upper atmosphere and the question of fixed limb darkening coefficients in fitting routines.
Sing, D. K.; Wakeford, H. R.; Showman, A. P.; Nikolov, N.; Fortney, J. J.; Burrows, A. S.; Ballester, G. E.; Deming, D.; Aigrain, S.; Désert, J.-M.; Gibson, N. P.; Henry, G. W.; Knutson, H.; Lecavelier des Etangs, A.; Pont, F.; Vidal-Madjar, A.; Williamson, M. W.; Wilson, P. A.
2015-01-01
We present Hubble Space Telescope optical and near-IR transmission spectra of the transiting hot-Jupiter WASP-31b. The spectrum covers 0.3-1.7 μm at a resolution R ˜ 70, which we combine with Spitzer photometry to cover the full-optical to IR. The spectrum is dominated by a cloud deck with a flat transmission spectrum which is apparent at wavelengths > 0.52 μm. The cloud deck is present at high altitudes and low pressures, as it covers the majority of the expected optical Na line and near-IR H2O features. While Na I absorption is not clearly identified, the resulting spectrum does show a very strong potassium feature detected at the 4.2σ confidence level. Broadened alkali wings are not detected, indicating pressures below ˜10 mbar. The lack of Na and strong K is the first indication of a sub-solar Na/K abundance ratio in a planetary atmosphere (ln[Na/K] = -3.3 ± 2.8), which could potentially be explained by Na condensation on the planet's night side, or primordial abundance variations. A strong Rayleigh scattering signature is detected at short wavelengths, with a 4σ significant slope. Two distinct aerosol size populations can explain the spectra, with a smaller sub-micron size grain population reaching high altitudes producing a blue Rayleigh scattering signature on top of a larger, lower lying population responsible for the flat cloud deck at longer wavelengths. We estimate that the atmospheric circulation is sufficiently strong to mix micron size particles upwards to the required 1-10 mbar pressures, necessary to explain the cloud deck. These results further confirm the importance of clouds in hot Jupiters, which can potentially dominate the overall spectra and may alter the abundances of key gaseous species.
Field-Correlation Effects on Rayleigh-Enhanced Nondegenerate Four-Wave Mixing
王延帮; 姜谦; 米辛; 俞祖和; 傅盘铭
2002-01-01
We study Rayleigh-enhanced nondegenerate four-wave mixing (NFWM) with time-delayed, correlated fluctuating fields. The importance of the field correlation is revealed in the Rayleigh-enhanced NFWM spectrum when the time delay is varied. The Rayleigh-enhanced NFWM is employed to study the ultrafast processes in the frequency domain. A relaxation time as short as 220 fs was deduced in the Rayleigh-enhanced NFWM experiments in carbon disulphide.
Quantum Effects on Rayleigh-Taylor Instability of Incompressible Plasma in a Vertical Magnetic Field
G.A.Hoshoudy
2010-01-01
@@ Quantum effects on Rayleigh-Taylor instability of a stratified incompressible plasmas layer under the influence of vertical magnetic field are investigated.The solutions of the linearized equations of motion together with the boundary conditions lead to deriving the relation between square normalized growth rate and square normalized wawe number in two algebraic equations and are numerically analyzed.In the case of the real solution of these two equations,they can be combined to generate a single equation.The results show that the presence of vertical magnetic field beside the quantum effect will bring about more stability on the growth rate of unstable configuration.
无
2008-01-01
In pH 4.2-5.0 Britton-Robinson buffer solution medium, fluoroquinolone antibiotics (FLQs), such as ciprofloxacin (CIP), norfloxacin (NOR), ofloxacin (OF), levofloxacin (LEV), lomefloxacin (LOM), and sparfloxacin (SPA), react with Cu (Ⅱ) to form chelate cations, which further bind with erythrosine to form the ion association complexes. They can result in the changes of the absorption spectra. Simultaneously, erythrosine fades obviously and the maximum fading wavelength is located at 526 nm. The fading reactions have high sensitivities. Thus, new spectrophotometries of determination for these drugs are developed. The ion-association reactions result in the quenching of fluorescence, which also have high sensitivities. The detection limits for six antibiotics are in the range of 7.1-12.2 μg·L-1. Furthermore, the reactions can result in the enhancement of resonance Rayleigh scattering (RRS). The maximum scattering peaks of six ion-association complexes are located at 566 nm, and there are two small RRS peaks at 333 nm and 287 nm. The detection limits for fluoroquinolone antibiotics are in the range of 1.70-3.10 μg·L-1 for RRS method. Among the above three methods, the RRS method has the highest sensitivity. In this work, we investigated the spectral characteristics of the absorption, fluorescence and RRS, the optimum conditions of the reactions, and the properties of the analytical chemistry. In addition, the mechanism of reactions were discussed by density function theory (DFT) and AM1 methods.
Effects on PP waves and Rayleigh waves of water column approximation
Zhou, Y.; Ni, S.
2015-12-01
Spectral-element method (SEM) combines the flexibility of the finite-element method and the accuracy of the pseudo-spectral method. It can handle the complexity of the 3-D earth model, such as heterogeneity of velocity and density, anisotropy, anelasticity, sharp velocity and density contrasts, topography. And with water column approximation, it can also deal with oceans. Because of its powerful ability, there are a wide range of application of SEM in studies of PP waves and Rayleigh waves. PP wave and its precursors have been used in measuring topography of 410 km or 660 km. Rayleigh waves are the most recognizable part of the seismograms and have been broadly applied in crustal and uppermost mantle tomography. In global SEM simulation, oceans are usually assumed to be incompressible, which means that the entire water column moves as a whole as a result of the normal displacement of the seafloor. It is necessary to investigate the accuracy of water column approximation when thickness of ocean approaches wavelength of the wave in the ocean water. In this paper, based on plane wave assumption, we study both the accurate form and water column approximate form of effective boundary condition. The reflection coefficient equation of PP waves with effective boundary of water was derived. Accurate and approximate PP reflection coefficient with oceans in different depth is demonstrated. The formula of Rayleigh wave phase velocity dispersion with effective water boundary is also investigated. It is shown that water column approximation in global SEM simulation is not sufficient for some parts of the ocean.
Effects of charged sand on electromagnetic wave propagation and its scattering field
HE; Qinshu; ZHOU; Youhe; ZHENG; Xiaojing
2006-01-01
Based on the Rayleigh's scattering theory, the effects of sandstorms on the propagation of electromagnetic wave with different visibilities are presented by solving the scattering field of charged sand particles. Because of the electric charges on the sand surface, the theoretical attenuation will be large enough to match the measured value under certain conditions. And the results show that the effect of sand with electric charges all over its surface on electromagnetic wave attenuation is the same as that of sand without charge, which proves that electric charges distribute on partial surface of the sand in fact.
Jian Guangde; Huang Lin; Qiu Xiaoming
2005-01-01
The assembling stabilizing effect of the finite Larmor radius (FLR) and the sheared axial flow (SAF) on the Rayleigh-Taylor instability in Z-pinch implosions is studied by means of the incompressible finite Larmor radius magnetohydrodynamic (MHD) equations. The finite Larmor radius effects are introduced in the momentum equation with the sheared axial flow through an anisotropic ion stress tensor. In this paper a linear mode equation is derived that is valid for arbitrary kL, where k is the wave number and L is the plasma shell thickness. Numerical solutions are presented. The results indicate that the short-wavelength modes of the RayleighTaylor instability are easily stabilized by the individual effect of the finite Larmor radius or the sheared axial flow. The assembling effects of the finite Larmor radius and sheared axial flow can heavily mitigate the Rayleigh-Taylor instability, and the unstable region can be compressed considerably.
Importance sampling the Rayleigh phase function
Frisvad, Jeppe Revall
2011-01-01
Rayleigh scattering is used frequently in Monte Carlo simulation of multiple scattering. The Rayleigh phase function is quite simple, and one might expect that it should be simple to importance sample it efficiently. However, there seems to be no one good way of sampling it in the literature. Thi....... This paper provides the details of several different techniques for importance sampling the Rayleigh phase function, and it includes a comparison of their performance as well as hints toward efficient implementation.......Rayleigh scattering is used frequently in Monte Carlo simulation of multiple scattering. The Rayleigh phase function is quite simple, and one might expect that it should be simple to importance sample it efficiently. However, there seems to be no one good way of sampling it in the literature...
Revisiting the Effects of Compressibility on the Rayleigh-Taylor Instability
ZHOU Qianhong; LI Ding
2007-01-01
The effects of compressibility on the Rayleigh-Taylor instability(RTI)are investigated.It is shown that the controversy over compressibility effects in the previous studies is due to improper comparison,in which the density varying effect obscures the real role of compressibility.After eliminating the density varying effect,it is found that the compressibility destabilizes RTI in both the cases of constant density and exponentially varying density when M<1.This destabilizing effect is more important at smaller values of the Atwood number AT or greater values of gravity g,and the increment in the growth rate produced by compressibility depends inversely on the pressure p or the ratio of specific heat I.
Nonequilibrium thermohydrodynamic effects on the Rayleigh-Taylor instability in compressible flows
Lai, Huilin; Xu, Aiguo; Zhang, Guangcai; Gan, Yanbiao; Ying, Yangjun; Succi, Sauro
2016-08-01
The effects of compressibility on Rayleigh-Taylor instability (RTI) are investigated by inspecting the interplay between thermodynamic and hydrodynamic nonequilibrium phenomena (TNE, HNE, respectively) via a discrete Boltzmann model. Two effective approaches are presented, one tracking the evolution of the local TNE effects and the other focusing on the evolution of the mean temperature of the fluid, to track the complex interfaces separating the bubble and the spike regions of the flow. It is found that both the compressibility effects and the global TNE intensity show opposite trends in the initial and the later stages of the RTI. Compressibility delays the initial stage of RTI and accelerates the later stage. Meanwhile, the TNE characteristics are generally enhanced by the compressibility, especially in the later stage. The global or mean thermodynamic nonequilibrium indicators provide physical criteria to discriminate between the two stages of the RTI.
Sound scattering at fluid-fluid rough surface
无
2008-01-01
Extinction theorem was used to deduce the first order scattering cross-section including the double scattering effects for the fluid-fluid rough surface. If the double scattering effects are neglected in the present method, the scattering cross-section agrees with the result obtained by the perturbation method based on Rayleigh hypothesis. Calculations of scattering strength were carried out, and comparisons with the first-order perturbation method based on Rayleigh hypothesis were also done. The results show that double scattering effects are obvious with the increase of the root mean square of surface height and the grazing angle when the valid condition k1h < 1 is satisfied.
Goryachev, Maxim; Creedon, Daniel L; Galliou, Serge; Tobar, Michael E
2013-08-23
The confinement of high frequency phonons approaching 1 GHz is demonstrated in phonon-trapping acoustic cavities at cryogenic temperatures using a low-coupled network approach. The frequency range is extended by nearly an order of magnitude, with excitation at greater than the 200th overtone achieved for the first time. Such a high frequency operation reveals Rayleigh-type phonon scattering losses due to highly diluted lattice impurities and corresponding glasslike behavior, with a maximum Q(L)×f product of 8.6×10(17) at 3.8 K and 4×10(17) at 15 mK. This suggests a limit on the Q×f product due to unavoidable crystal disorder. Operation at 15 mK is high enough in frequency that the average phonon occupation number is less than unity, with a loaded quality factor above half a billion. This work represents significant progress towards the utilization of such acoustic cavities for hybrid quantum systems.
Lu, Xin; Zhang, Dan; Liu, Chengwei; Xu, Qin; Zhao, Shulin
2009-12-01
A resonance Rayleigh scattering (RRS) detection approach was developed to detect sisomicin (Siso) in rat serum following chromatographic separation. The detection principle is based on the enhancement of RRS intensity of ion-association complex formed from aminoglycosides and pontamine sky blue (PSB) used as molecular recognition probe. The high-performance liquid chromatography (HPLC) coupled with RRS detection scheme was implemented post-column by mixing a PSB solution with the column eluent prior to detection. The RRS signal was detected by fluorescence detector at lambda(ex)=lambda(em)=365 nm. Separation and detection conditions were optimized. Siso and etimicin (Eti) chosen as the internal standard (IS) were separated on a C(18) reversed phase column with the mobile phase consisting of a ternary mixture of 20mM sodium acetate aqueous solution-methanol (92:8, v/v) containing 0.22% TFA (v/v). The limit of detection (S/N=3) for Siso was 18 ng. A calibration curve ranged from 25 ng to 700 ng shown to be linear. The presented method was applied for the determination of Siso in rat serum and used for the pharmacokinetics study of Siso in rat.
Yang, Qingling; Liu, Jian; Li, Banglin; Hu, Xiaoli; Liu, Shaopu; Chen, Gangcai
2016-10-01
In this paper, Hg2 + ions are demonstrated to form anionic [HgI4]2 - complexes after interacting with massive amount of I- ions. Subsequently, the addition of tetradecyl pyridyl bromide (TPB) can make [HgI4]2 - anionic complexes react with univalent tetradecyl pyridyl cationic ions (TP+), forming dispersed ion-association complexes (TP)2(HgI4). Due to the extrusion action of water and Van der Waals force, the hydrophobic ion-association complexes aggregate together, forming dispersed nanoparticles with an average size of about 8.5 nm. Meanwhile, resonance Rayleigh scattering (RRS) intensity is apparently enhanced due to the formation of (TP)2(HgI4) ion-association nanoparticles, contributing to a novel technique for Hg2 + detection. The wavelength of 365 nm is chosen as a detection wavelength and several conditions affecting the RRS responses of Hg2 + are optimized. Under the optimum condition, the developed method is used for the determination of Hg2 + in aqueous solution and the detection limit is estimated to be 0.8 ng mL- 1. Finally, the practical application of the developed method can be confirmed through the detections of Hg2 + in waste and river water samples with satisfactory results.
Duboisset, J; Matar, G; Russier-Antoine, I; Benichou, E; Bachelier, G; Jonin, Ch; Ficheux, D; Besson, F; Brevet, P F
2010-11-01
We report the first hyperpolarizability of tryptophan (Trp) and tyrosine (Tyr) and an upper limit for that of phenylalanine (Phe), three natural aromatic amino acids. The measurements were performed with hyper-Rayleigh scattering in an aqueous Tris buffer solution at a pH of 8.5 and 150 mM salt concentration with a fundamental wavelength of 780 nm. A value of (4.7 ± 0.7) × 10(-30) esu is found for Trp and (4.1 ± 0.7) × 10(-30) esu for Tyr whereas the upper limit of 1.4 × 10(-30) esu is found for that of Phe due to its limited solubility. The influence of the presence of lysine (Lys) in close vicinity of Trp is investigated with a measurement of the first hyperpolarizabilty of Trp in an excess of Lys and compared to the first hyperpolarizability obtained for the tripeptide Lys-Trp-Lys. The clear decrease of the values measured in these two cases indicates that the first hyperpolarizabilty of Trp is very sensitive to its local environment.
2008-01-01
In pH 4.2-5.0 Britton-Robinson buffer solution medium, fluoroquinolone antibiotics (FLQs), such as ciprofloxacin (CIP), norfloxacin (NOR), ofloxacin (OF), levofloxacin (LEV), lomefloxacin (LOM), and sparfloxacin (SPA), react with Cu (II) to form chelate cations, which further bind with erythrosine to form the ion association complexes. They can result in the changes of the absorption spectra. Simultane- ously, erythrosine fades obviously and the maximum fading wavelength is located at 526 nm. The fad- ing reactions have high sensitivities. Thus, new spectrophotometries of determination for these drugs are developed. The ion-association reactions result in the quenching of fluorescence, which also have high sensitivities. The detection limits for six antibiotics are in the range of 7.1-12.2 μg·L?1. Furthermore, the reactions can result in the enhancement of resonance Rayleigh scattering (RRS). The maximum scattering peaks of six ion-association complexes are located at 566 nm, and there are two small RRS peaks at 333 nm and 287 nm. The detection limits for fluoroquinolone antibiotics are in the range of 1.70 -3.10 μg·L?1 for RRS method. Among the above three methods, the RRS method has the highest sen- sitivity. In this work, we investigated the spectral characteristics of the absorption, fluorescence and RRS, the optimum conditions of the reactions, and the properties of the analytical chemistry. In addi- tion, the mechanism of reactions were discussed by density function theory (DFT) and AM1 methods.
The effect of a magnetic field on the development of Rayleigh Taylor type instability
Syusyukin, A.I.
1984-01-01
The results are presented of an experimental study of magnetohydrodynamic (MGD) instability of the Rayleigh Taylor type. The effect of a magnetic field on the development of magnetohydrodynamic instability was studied in the free surfaces of an accelerating electricity conducting piston. The tests were conducted with a liquid metallic piston and with a piston which is made up of a liquid which does not conduct electricity and one which does. It is shown that a rise in the magnetic induction leads to a more intense development of the instability which is accompanied by a more rapid destruction of the dense structure of the piston. The mechanism of destruction of a free surface under the effects of bulk forces is discussed.
Proximity effect correction concerning forward scattering
Tsunoda, Dai; Shoji, Masahiro; Tsunoe, Hiroyuki
2010-09-01
The Proximity Effect is a critical problem in EB Lithography which is used in Photomask writing. Proximity Effect means that an electron shot by gun scatters by collided with resist molecule or substrate atom causes CD variation depending on pattern density [1]. Scattering by collision with resist molecule is called as "forward scattering", that affects in dozens of nanometer range, and with substrate atom is called as "backward scattering, that affects approximately 10 micrometer in 50keV acceleration voltage respectively. In conventional Proximity Effect Correction (PEC) for mask writing, we don't need to think forward scattering effect. However we should think about forward scattering because of smaller feature size. We have proposed a PEC software product named "PATACON PC-Cluster"[2], which can concern forward scattering and calculate optimum dose modulation. In this communication, we explain the PEC processing throughput when the that takes forward scattering into account. The key technique is to use different processing field size for forward scattering calculation. Additionally, the possibility is shown that effective PEC may be available by connecting forward scattering and backward scattering.
Light scattering from exoplanet oceans and atmospheres
Zugger, Michael E; Williams, Darren M; Kane, Timothy J; Philbrick, C Russell
2010-01-01
Orbital variation in polarized and unpolarized reflected starlight from exoplanets could eventually be used to detect liquid water on planet surfaces. Exoplanets with rough surfaces, or those dominated by atmospheric Rayleigh scattering, should reach peak brightness in full phase, orbital longitude (OL) = 180 degrees, whereas ocean-covered planets with transparent atmospheres should reach peak brightness in crescent phase near OL = 30 degrees. Application of Fresnel theory to a planet with no atmosphere covered by a calm ocean predicts a peak polarization fraction of 1 at OL = 74 degrees; however, our model shows that clouds, wind-driven waves, aerosols, absorption, and Rayleigh scattering in the atmosphere and within the water column, dilute the polarization fraction and shift the peak to other OLs. Observing at longer wavelengths reduces the obfuscation of the water polarization signature by Rayleigh scattering but does not mitigate the other effects. Planets with thick Rayleigh scattering atmospheres reach...
Compressibility Effect on the Rayleigh-Taylor Instability with Sheared Magnetic Fields
Ruderman, M. S.
2017-04-01
We study the effect of plasma compressibility on the Rayleigh-Taylor instability of a magnetic interface with a sheared magnetic field. We assume that the plasma is ideal and the equilibrium quantities are constant above and below the interface. We derive the dispersion equation. Written in dimensionless variables, it contains seven dimensionless parameters: the ratio of plasma densities above and below the interface ζ, the ratio of magnetic field magnitude squared χ, the shear angle α, the plasma beta above and below the interface, β2 and β1, the angle between the perturbation wave number and the magnetic field direction above the interface φ, and the dimensionless wave number κ. Only six of these parameters are independent because χ, β1, and β2 are related by the condition of total pressure continuity at the interface. Only perturbations with the wave number smaller than the critical wave number are unstable. The critical wave number depends on φ, but it is independent of β1 and β2, and is the same as that in the incompressible plasma approximation. The dispersion equation is solved numerically with ζ= 100, χ= 1, and β1 = β2 = β. We obtain the following results. When β decreases, so does the maximum instability increment. However, the effect is very moderate. It is more pronounced for high values of α. We also calculate the dependence on φ of the maximum instability increment with respect to κ. The instability increment takes its maximum at φ= φm. Again, the decrease of β results in the reduction of the instability increment. This reduction is more pronounced for high values of |φ- φm|. When both α and |φ- φm| are small, the reduction effect is practically negligible. The theoretical results are applied to the magnetic Rayleigh-Taylor instability of prominence threads in the solar atmosphere.
The effect of normal electric field on the evolution of immiscible Rayleigh-Taylor instability
Tofighi, Nima; Ozbulut, Murat; Feng, James J.; Yildiz, Mehmet
2016-10-01
Manipulation of the Rayleigh-Taylor instability using an external electric field has been the subject of many studies. However, most of these studies are focused on early stages of the evolution. In this work, the long-term evolution of the instability is investigated, focusing on the forces acting on the interface between the two fluids. To this end, numerical simulations are carried out at various electric permittivity and conductivity ratios as well as electric field intensities using Smoothed Particle Hydrodynamics method. The electric field is applied in parallel to gravity to maintain unstable evolution. The results show that increasing top-to-bottom permittivity ratio increases the rising velocity of the bubble while hindering the spike descent. The opposite trend is observed for increasing top-to-bottom conductivity ratio. These effects are amplified at larger electric field intensities, resulting in narrower structures as the response to the excitation is non-uniform along the interface.
Effect of enhanced thermal dissipation on the Rayleigh-Taylor instability in emulsion-like media
Toor, A.; Ryutov, D.
1997-07-01
Rayleigh-Taylor instability in a finely structured emulsion-like medium consisting of the two components of different compressibility is considered. Although the term ``emulsion`` is used to describe the structure of the medium, under typical fast Z-pinch conditions both components behave as gases. The two components are chosen in such a way that their densities in the unperturbed state are approximately equal. Specific emphasis has been made on the analysis of perturbations with the scale {lambda} considerably exceeding the size of the grains a. Averaged equations describing such perturbations am derived. The difference in compressibility of the two components leads to the formation of temperature variations at the scale a, and increases the rate of the thermal dissipation by a factor ({lambda}/a){sup 2}. The strongest stabilizing effect of the thermal dissipation takes place when the thermal relaxation time is comparable with the instability growth rate.
The effects of Ekman pumping on quasi-geostrophic Rayleigh-Benard convection
Plumley, Meredith; Marti, Philippe; Stellmach, Stephan
2016-01-01
Numerical simulations of 3D, rapidly rotating Rayleigh-Benard convection are performed using an asymptotic quasi-geostrophic model that incorporates the effects of no-slip boundaries through (i) parameterized Ekman pumping boundary conditions, and (ii) a thermal wind boundary layer that regularizes the enhanced thermal fluctuations induced by pumping. The fidelity of the model, obtained by an asymptotic reduction of the Navier-Stokes equations that implicitly enforces a pointwise geostrophic balance, is explored for the first time by comparisons of simulations against the findings of direct numerical simulations and laboratory experiments. Results from these methods have established Ekman pumping as the mechanism responsible for significantly enhancing the vertical heat transport. This asymptotic model demonstrates excellent agreement over a range of thermal forcing for Pr ~1 when compared with results from experiments and DNS at maximal values of their attainable rotation rates, as measured by the Ekman numb...
Wang Lifeng [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Peng Jingdong [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)], E-mail: hxpengjd@swu.edu.cn; Liu Limin [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)
2008-12-07
A new reversed-phase high performance liquid chromatography with resonance Rayleigh scattering detection (HPLC-RRS) was developed for simultaneous separation and determination of four tetracycline antibiotics (TCs). A good chromatographic separation among the compounds was achieved using a Synergi Fusion-RP column (150 mm x 4.6 mm; 4 {mu}m) and a mobile phase consisting of methanol-acetonitrile-oxalic acid (5 mM) at the flow rate of 0.8 mL min{sup -1}. Column temperature was 30 deg. C. The RRS signal was detected at {lambda}{sub ex} = {lambda}{sub em} = 370 nm. The recoveries of sample added standard ranged from 95.3% to 103.5%, and the relative standard deviation was below 2.79%. A detection limit of 2.12-5.12 {mu}g mL{sup -1} was reached and a linear range was found between peak height and concentration in the range of 10.36-518.0 {mu}g mL{sup -1} for oxytetracycline (OTC), 12.11-605.5 {mu}g mL{sup -1} for tetracycline (TC), 11.79-589.5 {mu}g mL{sup -1} for chlortetracycline (CTC) and 10.32-516.0 {mu}g mL{sup -1} for doxycycline (DC). The linear regression coefficients were all above 0.999. The method has been applied successfully to the determination of OTC, TC, CTC, DC in pharmaceutical formulations and in honey. The method was simple, rapid and showed a better linear relation and high repeatability.
Yang, Jidong; Tan, Xuanping; Zhang, Xiaoning; Yang, Qiong; Shen, Yizhong
2015-01-01
A simple protocol that can be used to simultaneously determinate enantiomers is extremely intriguing and useful. In this study, we proposed a low-cost, facile, sensitive method for simultaneous determination. The molecular recognition of Cu(2+) functionalized N-acetyl-l-cysteine capped CdTe quantum dots (Cu(2+)-NALC/CdTe QDs) with phenylalanine (PA) enantiomers was investigated based on the resonance Rayleigh scattering (RRS) spectral technique. The RRS intensity of NALC/CdTe QDs is very weak, but Cu(2+) functionalized NALC/CdTe QDs have extremely high RRS intensity, the most important observations are that PA could quench the RRS intensity of Cu(2+)-NALC/CdTe QDs, and that l-PA and d-PA have different degree of influence. In addition, those experimental factors such as acidity, concentration of Cu(2+) and reaction time were investigated in regards to their effects on enantioselective interaction. Finally, the applicability of the chiral recognized sensor for the analysis of chiral mixtures on enantiomers has been demonstrated, and the results that were obtained high precision (<4.63%) and low error (<3.06%).
Electromagnetic Scattering by Spheres of Topological Insulators
Ge, Lixin; Zi, Jian
2015-01-01
The electromagnetic scattering properties of topological insulator (TI) spheres are systematically studied in this paper. Unconventional backward scattering caused by the topological magneto-electric (TME) effect of TIs are found in both Rayleigh and Mie scattering regimes. This enhanced backward scattering can be achieved by introducing an impedance-matched background which can suppress the bulk scattering. For the cross-polarized scattering coefficients, interesting antiresonances are found in the Mie scattering regime, wherein the cross-polarized electromagnetic fields induced by the TME effect are trapped inside TI spheres. In the Rayleigh limit, the quantized TME effect of TIs can be determined by measuring the electric-field components of scattered waves in the far field.
3-D simulations to investigate initial condition effects on the growth of Rayleigh-Taylor mixing
Andrews, Malcolm J [Los Alamos National Laboratory
2008-01-01
The effect of initial conditions on the growth rate of turbulent Rayleigh-Taylor (RT) mixing has been studied using carefully formulated numerical simulations. An integrated large-eddy simulation (ILES) that uses a finite-volume technique was employed to solve the three-dimensional incompressible Euler equations with numerical dissipation. The initial conditions were chosen to test the dependence of the RT growth parameters ({alpha}{sub b}, {alpha}{sub s}) on variations in (a) the spectral bandwidth, (b) the spectral shape, and (c) discrete banded spectra. Our findings support the notion that the overall growth of the RT mixing is strongly dependent on initial conditions. Variation in spectral shapes and bandwidths are found to have a complex effect of the late time development of the RT mixing layer, and raise the question of whether we can design RT transition and turbulence based on our choice of initial conditions. In addition, our results provide a useful database for the initialization and development of closures describing RT transition and turbulence.
Solar effect on the Rayleigh-Taylor instability growth rate as simulated by the NCAR TIEGCM
Wu, Qian
2017-04-01
The TIEGCM (Thermosphere Ionosphere Electrodynamics General Circulation Model) is used to investigate the solar effect on the equatorial ionospheric Rayleigh-Taylor (R-T) instability growth rate, which is responsible for the occurrence of the plasma bubbles. The R-T growth rate is calculated for the solar maximum year 2003 and minimum 2009. The growth rate is strongly dependent on the solar activity. During solar maximum, the pre-reversal enhancement is much stronger leading to higher R-T growth rate. The R-T growth rates from the TIEGCM follow the same solar dependence as the observed occurrence of equatorial plasma bubbles by DMSP satellites. The R-T growth rate also enhances when the day/night terminator is parallel to the magnetic field line near the equator. The R-T growth rate does not correlate well with the solar F10.7 index on a short time scale ( 10 days) because the field-line integrated electron content gradient cancels out the positive correlation between the vertical ion drift with the F10.7 index. The TIEGCM result shows the importance of the electron content gradient to the R-T growth rate and the plasma bubble occurrence. The bubble occurrence rates were estimated based on the vertical ion drift simulation results.
Effect of noise on Rayleigh-Taylor mixing with space-dependent acceleration
Pandian, Arun; Abarzhi, Snezhana
2016-11-01
We analyze, for the first time by our knowledge, the effect of noise on Rayleigh-Taylor (RT) mixing with space-dependent acceleration by applying the stochastic model. In these conditions, the RT mixing is a statistically unsteady process where the means values of the flow quantities vary in space and time, and there are also the space and time dependent fluctuations around these mean values. The stochastic model is derived from the momentum model and is represented by a set of nonlinear differential equations with multiplicative noise. The models equations are solved theoretically and numerically. Investigating a broad range of values of acceleration, self-similar asymptotic solutions are found in the mixing regime. There are two types of mixing sub-regimes (acceleration-driven and dissipation-driven respectively), each of which has its own types of solutions and characteristic values with the latter saturating to a value on the order of one. It is also observed that the representation of the dynamics in an implicit form is noisier as compared to the case of an explicit time-dependent form. The work is supported by the US National Science Foundation.
Effects of acceleration rate on Rayleigh-Taylor instability in elastic-plastic materials
Banerjee, Arindam; Polavarapu, Rinosh
2016-11-01
The effect of acceleration rate in the elastic-plastic transition stage of Rayleigh-Taylor instability in an accelerated non-Newtonian material is investigated experimentally using a rotating wheel experiment. A non-Newtonian material (mayonnaise) was accelerated at different rates by varying the angular acceleration of a rotating wheel and growth patterns of single mode perturbations with different combinations of amplitude and wavelength were analyzed. Experiments were run at two different acceleration rates to compare with experiments presented in prior years at APS DFD meetings and the peak amplitude responses are captured using a high-speed camera. Similar to the instability acceleration, the elastic-plastic transition acceleration is found to be increasing with increase in acceleration rate for a given amplitude and wavelength. The experimental results will be compared to various analytical strength models and prior experimental studies using Newtonian fluids. Authors acknowledge funding support from Los Alamos National Lab subcontract(370333) and DOE-SSAA Grant (DE-NA0001975).
Viscous effects on the Rayleigh-Taylor instability with background temperature gradient
Gerashchenko, S
2016-01-01
The growth rate of the compressible Rayleigh-Taylor instability is studied in the presence of a background temperature gradient, $\\Theta$, using a normal mode analysis. The effect of $\\Theta$ variation is examined for three interface types corresponding to combinations of the viscous properties of the fluids (inviscid-inviscid, viscous-viscous and viscous-inviscid) at different Atwood numbers, $At$, and, when at least one of the fluids' viscosity is non-zero, as a function of the Grashof number. For the general case, the resulting ordinary differential equations are solved numerically; however, dispersion relations for the growth rate are presented for several limiting cases. An analytical solution is found for the inviscid-inviscid interface and the corresponding dispersion equation for the growth rate is obtained in the limit of a large $\\Theta$. For the viscous-inviscid case, a dispersion relation is derived in the incompressible limit and $\\Theta=0$. Compared to $\\Theta=0$ case, the role of $\\Theta0$ (col...
Numerical simulation of helical-vortex effects in Rayleigh-Bénard convection
G. V. Levina
2006-01-01
Full Text Available A numerical approach is substantiated for searching for the large-scale alpha-like instability in thermoconvective turbulence. The main idea of the search strategy is the application of a forcing function which can have a physical interpretation. The forcing simulates the influence of small-scale helical turbulence generated in a rotating fluid with internal heat sources and is applied to naturally induced fully developed convective flows. The strategy is tested using the Rayleigh-Bénard convection in an extended horizontal layer of incompressible fluid heated from below. The most important finding is an enlargement of the typical horizontal scale of the forming helical convective structures accompanied by a cells merging, an essential increase in the kinetic energy of flows and intensification of heat transfer. The results of modeling allow explaining how the helical feedback can work providing the non-zero mean helicity generation and the mutual intensification of horizontal and vertical circulation, and demonstrate how the energy of the additional helical source can be effectively converted into the energy of intensive large-scale vortex flow.
Scattering effect on entanglement propagation in RCFTs
Numasawa, Tokiro
2016-01-01
In this paper we discuss the scattering effect on entanglement propagation in RCFTs. In our setup, we consider the time evolution of excited states created by the insertion of many local operators. Our results show that because of the finiteness of quantum dimension, entanglement is not changed after the scattering in RCFTs. In this mean, entanglement is conserved after the scattering event in RCFTs, which reflects the integrability of the system. Our results are also consistent with the free quasiparticle picture after the global quenches.
Effect of plumes on measuring the large scale circulation in turbulent Rayleigh-Bénard convection
Stevens, Richard Johannes Antonius Maria; Clercx, H.J.H.; Lohse, Detlef
2011-01-01
We studied the properties of the large-scale circulation (LSC) in turbulent Rayleigh-Bénard (RB) convection by using results from direct numerical simulations in which we placed a large number of numerical probes close to the sidewall. The LSC orientation is determined by either a cosine or a
Absorbing aerosol radiative effects in the limb-scatter viewing geometry
A. Wiacek
2013-02-01
Full Text Available The limb-scatter satellite viewing geometry is well suited to detecting low-concentration aerosols in the upper troposphere due to its long observation path length (~ 50–100 km, high vertical resolution (~ 1–2 km and good geographic coverage. We use the fully three-dimensional radiative transfer code SASKTRAN to simulate the sensitivity of limb-scatter viewing Odin/OSIRIS satellite measurements to absorbing mineral dust and carbonaceous aerosols (smoke and pure soot, as well as to non-absorbing sulfate aerosols and ice in the upper troposphere.
At long wavelengths (813 nm the addition of all aerosols (except soot to an air only atmosphere produced a radiance increase as compared to air only, on account of the low Rayleigh scattering in air only at 813 nm. The radiance reduction due to soot aerosol was negligible (< 0.1% at all heights (0–100 km.
At short wavelengths (337, 377, 452 nm, we found that the addition of any aerosol species to an air only atmosphere caused a decrease in single-scattered radiation due to an extinction of Rayleigh scattering in the direction of OSIRIS. The reduction was clearly related to particle size first, with absorption responsible for second-order effects only. Multiple-scattered radiation could either increase or decrease in the presence of an aerosol species, depending both on particle size and absorption. Large scatterers (ice, mineral dust all increased multiple-scattered radiation within, below and above the aerosol layer. Small, highly absorbing pure soot particles produced a negligible multiple-scattering response (< 0.1% at all heights, primarily confined to within and below the soot layer. Medium-sized scatterers produced a multiple-scattering response that depended on their absorbing properties. Increased radiances were simulated as compared to air only at all short wavelengths (337, 377 and 452 nm for sulfate aerosol particles (non-absorbing while decreased radiances were
Multiple scattering effects on spaceborne lidar
Winker, David M.; Poole, Lamont R.
1992-01-01
A semianalytic Monte Carlo code originally developed for oceanographic calculations (Poole et al., 1981) has been modified for use in studying multiple scattering of space-based lidar. The approach is very similar to that described by Kunkel and Weinman (1976). The trajectory of each photon is followed from the transmitter through multiple scattering until the photon is either scattered backward out of the atmosphere, scattered forward into the ground and absorbed, or scattered out the sides of the cloud. The probability that the photon will return directly to the detector is computed and summed over all significant scattering events within the field of view of the detector. Multiple scattering of the lidar pulse causes an apparent increase in the transmittance of the medium. Multiple scattering effects for space-based lidar are more significant than for ground-based lidar due to the much larger beam diameter in the atmosphere. These larger diameters are due not only to the greater range between the lidar and the scattering volume, but also the need to maintain relatively large beam divergences to satisfy eye safety restrictions on the laser irradiance at the Earth's surface. The simulations presented here are for a wavelength of 1064 nm and the Deirmendjian C1 phase function, which yields an extinction coefficient of 17.259/km. We have looked at two cases: a space-based lidar at 296 km observing a C1 cloud 293 km from the lidar and, for comparison purposes, a ground-based lidar looking at a C1 cloud with a base height of either 2 km or 5 km. The C1 size distribution roughly approximates that of stratocumulus or altocumulus clouds (aufm Kampe and Weickmann, 1957).
Two-dimensional simulation of Poiseuille-Rayleigh-Bénard flows in binary fluids with Soret effect
无
2007-01-01
Poiseuille-Rayleigh-Bénard flows in binary fluids with Soret effect are directly simulated by a mixed finite element method.A temperature perturbation is used as an initial disturbed source for the basic parallel flows.The whole spatio-temporal evolution of the binary fluid flows is exhibited:initially only the disturbed mode with the wavenumber k=π is amplified while others are damped.and continuously the amplified mode grows further and the nonlinear effect becomes important;after a nonlinear evolution transition the flow system evolves finally into a periodic right traveling wave.
Krywonos, Andrey; Harvey, James E; Choi, Narak
2011-06-01
Scattering effects from microtopographic surface roughness are merely nonparaxial diffraction phenomena resulting from random phase variations in the reflected or transmitted wavefront. Rayleigh-Rice, Beckmann-Kirchhoff. or Harvey-Shack surface scatter theories are commonly used to predict surface scatter effects. Smooth-surface and/or paraxial approximations have severely limited the range of applicability of each of the above theoretical treatments. A recent linear systems formulation of nonparaxial scalar diffraction theory applied to surface scatter phenomena resulted first in an empirically modified Beckmann-Kirchhoff surface scatter model, then a generalized Harvey-Shack theory that produces accurate results for rougher surfaces than the Rayleigh-Rice theory and for larger incident and scattered angles than the classical Beckmann-Kirchhoff and the original Harvey-Shack theories. These new developments simplify the analysis and understanding of nonintuitive scattering behavior from rough surfaces illuminated at arbitrary incident angles.
Noninertial effects on nonrelativistic topological quantum scattering
Mota, H. F.; Bakke, K.
2017-08-01
We investigate noninertial effects on the scattering problem of a nonrelativistic particle in the cosmic string spacetime. By considering the nonrelativistic limit of the Dirac equation we are able to show, in the regime of small rotational frequencies, that the phase shift has two contribution: one related to the noninertial reference frame, and the other, due to the cosmic string conical topology. We also show that both the incident wave and the scattering amplitude are altered as a consequence of the noninertial reference frame and depend on the rotational frequency.
Prajapati, Ramprasad
2016-07-01
The Rayleigh-Taylor (R-T) instability is recently investigated is strongly coupled plasma looking to its importance in dense stellar systems and Inertial Confinement Fusion [1-3]. In the present work, the effect of quantum corrections are studied on Rayleigh-Taylor (R-T) instability and internal wave propagation in a strongly coupled, magnetized, viscoelastic fluid. The modified generalized hydrodynamic model is used to derive the analytical dispersion relation. The internal wave mode and dispersion relation are modified due to the presence of quantum corrections and viscoelastic effects. We observe that strong coupling effects and quantum corrections significantly modifies the dispersion characteristics. The dispersion relation is also discussed in weakly coupled (hydrodynamic) and strongly coupled (kinetic) limits. The explicit expression of R-T instability criterion is derived which is influenced by shear velocity and quantum corrections. Numerical calculations are performed in astrophysical and experimental relevance and it is examined that both the shear and quantum effects suppresses the growth rate of R-T instability. The possible application of the work is discussed in Inertial Confinement Fusion (ICF) to discuss the suppression of R-T instability under considered situation. References: [1] R. P. Prajapati, Phys. Plasmas 23, 022106 (2016). [2] K. Avinash and A. Sen, Phys. Plasmas 22, 083707 (2015). [3] A. Das and P. Kaw, Phys. Plasmas 21 (2014) 062102.
Effect of noise on Rayleigh-Taylor mixing with time-dependent acceleration
Swisher, Nora; Pandian, Arun; Abarzhi, Snezhana
2016-11-01
We perform a detailed stochastic study of Rayleigh-Taylor (RT) mixing with time-dependent acceleration. A set of nonlinear stochastic differential equations with multiplicative noise is derived on the basis of momentum model and group theory analysis. A broad range of parameters is investigated, and self-similar asymptotic solutions are found. The existence is shown of two sub-regimes of RT mixing dynamics - the acceleration-driven and the dissipation-driven mixing. In each sub-regime, statistic properties of the solutions are investigated, and dynamic invariants are found. Transition between the sub-regimes is studied. The work is supported by the US National Science Foundation.
Combined effect of horizontal magnetic field and vorticity on Rayleigh Taylor instability
Banerjee, Rahul
2016-01-01
In this research, the height, curvature and velocity of the bubble tip in Rayleigh-Taylor instability at arbitrary Atwood number with horizontal magnetic field are investigated. To support the earlier simulation and experimental results, the vorticity generation inside the bubble is introduced. It is found that, in early nonlinear stage, the temporal evolution of the bubble tip parameters depend essentially on the strength and initial perturbation of the magnetic field, although the asymptotic nature coincides with the non magnetic case. The model proposed here agrees with the previous linear, nonlinear and simulation observations.
Effects of Spherical Aberration on Optical Trapping Forces for Rayleigh Particles
YAO Xin-Cheng; LI Zhao-Lin; GUO Hong-Lian; CHENG Bing-Ying; ZHANG Dao-Zhong
2001-01-01
The trapping force on Rayleigh particles in an optical tweezers system with an oil immersion objective is calculated by an electromagnetic model. The results indicate that the stability of particles trapped will be affected by spherical aberration, which is caused by refractive difference between objective oil and water solution, when the specimen manipulated is suspended in a water solution. The trapping force and depth of potential well will decrease and the minimum of laser power for ensuring the stability of particles trapped will increase with the enhanced trapping depth.
Self-pulsing effect in chaotic scattering
Jung, C [Centro de Ciencias FIsicas, Universidad Nacional Autonoma de Mexico, Cuernavaca, Morelos (Mexico); MejIa-Monasterio, C [Centro de Ciencias FIsicas, Universidad Nacional Autonoma de Mexico, Cuernavaca, Morelos (Mexico); Merlo, O [Institut fuer Physik der Universitaet Basel, Basel (Switzerland); Seligman, T H [Centro de Ciencias FIsicas, Universidad Nacional Autonoma de Mexico, Cuernavaca, Morelos (Mexico)
2004-05-01
We study the quantum and classical scattering of Hamiltonian systems whose chaotic saddle is described by binary or ternary horseshoes. We are interested in situations for which a stable island, associated with the inner fundamental periodic orbit of the system exists and is large, but chaos around this island is well developed. Such situations are quite common as they correspond typically to the near-integrable domain in the transition from integrable to chaotic scattering. Both classical and quantum dynamics are analysed and in both cases, the most surprising effect is a periodic response to an incoming wave packet. The period of this self-pulsing effect or scattering echoes coincides with the mean period, by which the scattering trajectories rotate around the stable orbit. This period of rotation is directly related to the development stage of the underlying horseshoe. Therefore the predicted echoes will provide experimental access to topological information. We numerically test these results in kicked one-dimensional models and in open billiards.
Wang, H.; Currie, C. A.
2013-12-01
For many continental plates, significant vertical motion of Earth's surface has occurred within the plate interior which can not be clearly linked to plate tectonic processes. For example, several craton areas exhibit anomalous basins, e.g., the Williston basin, Illinois basin and Michigan basin in North America. In orogenic belts, there are examples of local areas (~100 km wide) where the surface has undergone subsidence and then uplift of >1 km, such as the Arizaro basin (central Andes) and Wallowa Mountains (northeast Oregon). Given the near-circular shape of the surface deflection, it has been suggested that they may be related to gravitational foundering of dense lower lithosphere, i.e., Rayleigh-Taylor instability (or 'RT drip'). In order to investigate the surface effects of an RT drip, we use two methods: (1) 2D thermal-mechanical numerical models to study links between drip dynamics and crustal deformation and (2) a theoretical analysis of the crustal deformation induced by stresses from the RT drip. The numerical models consist of a continental lithosphere overlying a sublithospheric mantle. A high-density material is placed in the mantle lithosphere or lower crust to initiate a drip event, and a stress-free boundary condition allows the development of surface topography during model evolution. A reasonable range of crustal viscosity and thickness is tested to study the RT drip in different tectonic settings, from a cold craton to a hot orogen with thick crust. Four types of surface deflection are observed: (1) subsidence; (2) subsidence followed by uplift; (3) uplift; and (4) little deflection. When the crust is relatively strong or thin, the surface has a negative elevation, forming a basin. For a weak or thick crust, the RT drip induces crustal flow, leading to crustal thickening that can uplift the surface; an extremely weak crust decouples the surface and RT drip and the surface is unperturbed. Our theoretical analysis considers the surface
The Effect of Anisotropic Scatter on Atmospheric Neutron Transport
2015-03-26
slab geometry, two studies were conducted exploring the relative effect of anisotropic scatter as compared to isotropic scatter in the center of mass... anisotropic scatter. In order to address this question, first anisotropic scatter was implemented, then verified, and finally, the measurement of the... measured value. The relative error between neutron counts in isotropic and anisotropic time- integrated energy bins, isotropic anisotropicrel
Effective Tree Scattering at L-Band
Kurum, Mehmet; ONeill, Peggy E.; Lang, Roger H.; Joseph, Alicia T.; Cosh, Michael H.; Jackson, Thomas J.
2011-01-01
For routine microwave Soil Moisture (SM) retrieval through vegetation, the tau-omega [1] model [zero-order Radiative Transfer (RT) solution] is attractive due to its simplicity and eases of inversion and implementation. It is the model used in baseline retrieval algorithms for several planned microwave space missions, such as ESA's Soil Moisture Ocean Salinity (SMOS) mission (launched November 2009) and NASA's Soil Moisture Active Passive (SMAP) mission (to be launched 2014/2015) [2 and 3]. These approaches are adapted for vegetated landscapes with effective vegetation parameters tau and omega by fitting experimental data or simulation outputs of a multiple scattering model [4-7]. The model has been validated over grasslands, agricultural crops, and generally light to moderate vegetation. As the density of vegetation increases, sensitivity to the underlying SM begins to degrade significantly and errors in the retrieved SM increase accordingly. The zero-order model also loses its validity when dense vegetation (i.e. forest, mature corn, etc.) includes scatterers, such as branches and trunks (or stalks in the case of corn), which are large with respect to the wavelength. The tau-omega model (when applied over moderately to densely vegetated landscapes) will need modification (in terms of form or effective parameterization) to enable accurate characterization of vegetation parameters with respect to specific tree types, anisotropic canopy structure, presence of leaves and/or understory. More scattering terms (at least up to first-order at L-band) should be included in the RT solutions for forest canopies [8]. Although not really suitable to forests, a zero-order tau-omega model might be applied to such vegetation canopies with large scatterers, but that equivalent or effective parameters would have to be used [4]. This requires that the effective values (vegetation opacity and single scattering albedo) need to be evaluated (compared) with theoretical definitions of
Perrett, Glynis M. [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Campbell, John L., E-mail: icampbel@uoguelph.ca [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Gellert, Ralf [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); King, Penelope L. [Research School of Earth Sciences, Australian National University, Canberra, ACT 0200 (Australia); Nield, Emily; O’Meara, Joanne M.; Pradler, Irina [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario N1G 2W1 (Canada)
2016-02-01
The intensity ratio C/R between Compton and Rayleigh scatter peaks of the exciting Pu L X-rays in the alpha particle X-ray spectrometer (APXS) is strongly affected by the presence of very light elements such as oxygen which cannot be detected directly by the APXS. C/R values are determined along with element concentrations by fitting APXS spectra of geochemical reference materials (GRMs) with the GUAPX code. A quantity K is defined as the ratio between the C/R value determined by Monte Carlo simulation based on the measured element concentrations and the fitted C/R value from the spectrum. To ensure optimally accurate K values, the choice of appropriate GRMs is explored in detail, with attention paid to Rb and Sr, whose characteristic Kα X-ray peaks overlap the Pu Lα scatter peaks. The resulting relationship between the ratio K and the overall oxygen fraction is linear. This provides a calibration from which the concentration of additional light invisible constituents (ALICs) such as water may be estimated in unknown rock and conglomerate samples. Several GRMs are used as ‘unknowns’ in order to evaluate the accuracy of ALIC concentrations derived in this manner.
Jiang, Fei
2016-11-01
In this article, we investigate the effect of viscosity on the largest growth rate in the linear Rayleigh-Taylor (RT) instability of a three-dimensional nonhomogeneous incompressible viscous flow in a bounded domain. By adapting a modified variational approach and careful analysis, we show that the largest growth rate in linear RT instability tends to zero as the viscosity coefficient goes to infinity. Moreover, the largest growth rate increasingly converges to one of the corresponding inviscid fluids as the viscosity coefficient goes to zero. Applying these analysis techniques to the corresponding viscous magnetohydrodynamic fluids, we can also show that the largest growth rate in linear magnetic RT instability tends to zero as the strength of horizontal (or vertical) magnetic field increasingly goes to a critical value.
Effect of Plumes on Measuring the Large Scale Circulation in Turbulent Rayleigh-B\\'enard Convection
Stevens, Richard J A M; Lohse, Detlef
2011-01-01
We studied the properties of the large-scale circulation (LSC) in turbulent Rayleigh-B\\'enard (RB) convection by using results from direct numerical simulations in which we placed a large number of numerical probes close to the sidewall. The LSC orientation is determined by either a cosine or a polynomial fit to the azimuthal temperature or azimuthal vertical velocity profile measured with the probes. We study the LSC in \\Gamma=D/L=1/2 and \\Gamma=1 samples, where D is the diameter and L the height. For Pr=6.4 in an aspect ratio \\Gamma=1 sample at $Ra=1\\times10^8$ and $5\\times10^8$ the obtained LSC orientation is the same, irrespective of whether the data of only 8 or all 64 probes per horizontal plane are considered. In a \\Gamma=1/2 sample with $Pr=0.7$ at $Ra=1\\times10^8$ the influence of plumes on the azimuthal temperature and azimuthal vertical velocity profiles is stronger. Due to passing plumes and/or the corner flow the apparent LSC orientation obtained using a cosine fit can result in a misinterpretati...
Khomenko, E; de Vicente, A; Collados, M; Luna, M
2014-01-01
We study the Rayleigh-Taylor instability (RTI) at a prominence-corona transition region in a non-linear regime. Our aim is to understand how the presence of neutral atoms in the prominence plasma influences the instability growth rate, and the evolution of velocity, magnetic field vector and thermodynamic parameters of turbulent drops. We perform 2.5D numerical simulations of the instability initiated by a multi-mode perturbation at the corona-prominence interface using a single-fluid MHD approach including a generalized Ohm's law. The initial equilibrium configuration is purely hydrostatic and contains a homogeneous horizontal magnetic field forming an angle with the direction in which the plasma is perturbed. We analyze simulations with two different orientations of the magnetic field. For each field orientation we compare two simulations, one for the pure MHD case, and one including the ambipolar diffusion in the Ohm's law (AD case). Other than that, both simulations for each field orientation are identica...
Virtual Bilepton Effects in polarized Moller Scattering
Meirose, B
2008-01-01
We investigate the indirect effects of heavy vector bileptons being exchanged in polarized Moller scattering, at the next generation of linear colliders. Considering both longitudinal and transverse beam polarization, and accounting for initial-state radiation, beamstrahlung and beam energy spread, we discuss how angular distributions and asymmetries can be used to detect clear signals of virtual bileptons, and the possibility of distinguishing theoretical models that incorporate these exotic particles. We then estimate 95% C.L. bounds on the mass of these vector bileptons and on their couplings to electrons.
Investigation of multiple scattering effects in aerosols
Deepak, A.
1980-01-01
The results are presented of investigations on the various aspects of multiple scattering effects on visible and infrared laser beams transversing dense fog oil aerosols contained in a chamber (4' x 4' x 9'). The report briefly describes: (1) the experimental details and measurements; (2) analytical representation of the aerosol size distribution data by two analytical models (the regularized power law distribution and the inverse modified gamma distribution); (3) retrieval of aerosol size distributions from multispectral optical depth measurements by two methods (the two and three parameter fast table search methods and the nonlinear least squares method); (4) modeling of the effects of aerosol microphysical (coagulation and evaporation) and dynamical processes (gravitational settling) on the temporal behavior of aerosol size distribution, and hence on the extinction of four laser beams with wavelengths 0.44, 0.6328, 1.15, and 3.39 micrometers; and (5) the exact and approximate formulations for four methods for computing the effects of multiple scattering on the transmittance of laser beams in dense aerosols, all of which are based on the solution of the radiative transfer equation under the small angle approximation.
Rayleigh surface waves, phonon mode conversion, and thermal transport in nanostructures
Maurer, Leon; Knezevic, Irena
We study the effects of phonon mode conversion and Rayleigh (surface) waves on thermal transport in nanostructures. We present a technique to calculate thermal conductivity in the elastic-solid approximation: a finite-difference time-domain (FDTD) solution of the elastic or scalar wave equations combined with the Green-Kubo formula. The technique is similar to an equilibrium molecular dynamics simulation, captures phonon wave behavior, and scales well to nanostructures that are too large to simulate with many other techniques. By imposing fixed or free boundary conditions, we can selectively turn off mode conversion and Rayleigh waves to study their effects. In the example case of graphenelike nanoribbons with rough edges, we find that mode conversion among bulk modes has little effect on thermal transport, but that conversion between bulk and Rayleigh waves can significantly reduce thermal conductivity. With increasing surface disorder, Rayleigh waves readily become trapped by the disorder and draw energy away from the propagating bulk modes, which lowers thermal conductivity. We discuss the implications on the accuracy of popular phonon-surface scattering models that stem from scalar wave equations and cannot capture mode conversion to Rayleigh waves.
Sound scattering at fluid-fluid rough surface
2008-01-01
Extinction theorem was used to deduce the first order scattering cross-section including the double scattering effects for the fluid-fluid rough surface.If the dou- ble scattering effects are neglected in the present method,the scattering cross-section agrees with the result obtained by the perturbation method based on Rayleigh hypothesis.Calculations of scattering strength were carried out,and comparisons with the first-order perturbation method based on Rayleigh hypothe- sis were also done.The results show that double scattering effects are obvious with the increase of the root mean square of surface height and the grazing angle when the valid condition k1h<1 is satisfied.
Investigation of Simulating Radar Images Concerning the Multipath Scattering Effect
Yang Chun-hua; Zhu Guo-qiang
2004-01-01
In the composed system of a target and rough surface, the electromagnetic scattering mechanism, especially the multipath scattering, is investigated. Using physical optics double bouncing algorithm, the multipath scattering model of the system has been established. Simulated by a wideband radar signal and based on fractal rough surface. the artificial echo of the target has been obtained in virtue of the established multipath scattering model. By simulating to image the target in one dimension using the artificial echo, two kinds of range profiles are attained. It is found that one is from the target and the other is from the multipath scattering effect.
Cheng, Jian-Ping; Zhang, Hong-Na; Cai, Wei-Hua; Li, Si-Ning; Li, Feng-Chen
2017-07-01
The present paper presents direct numerical simulations of Rayleigh-Bénard convection (RBC) in an enclosed cell filled with the polymer solution in order to investigate the viscoelastic effect on the characteristics of heat transport and large-scale circulation (LSC) of RBC. To overcome the difficulties in numerically solving a high Weissenberg number (Wi) problem of viscoelastic fluid flow with strong elastic effect, the log-conformation reformulation method was implemented. Numerical results showed that the addition of polymers reduced the heat flux and the amount of heat transfer reduction (HTR) behaves nonmonotonically, which firstly increases but then decreases with Wi. The maximum HTR reaches around 8.7 % at the critical Wi. The nonmonotonic behavior of HTR as a function of Wi was then corroborated with the modifications of the period of LSC and turbulent energy as well as viscous boundary layer thickness. Finally, a standard turbulent kinetic energy (TKE) budget analysis was done for the whole domain, the boundary layer region, and the bulk region. It showed that the role change of elastic stress contributions to TKE is mainly responsible for this nonmonotonic behavior of HTR.
Seismic Rayleigh Wave Digital Processing Technology
Jie, Li
2013-04-01
In Rayleigh wave exploration, the digital processing of data plays a very important position. This directly affects the interpretation of ground effect. Therefore, the use of accurate processing software and effective method in the Rayleigh wave exploration has important theoretical and practical significance. Previously, Rayleigh wave dispersion curve obtained by the one-dimensional phase analysis. This method requires channel spacing should be less than the effective wavelength. And minimal phase error will cause great changes in the phase velocity of Rayleigh wave. Damped least square method is a local linear model. It is easy to cause that inversion objective function cannot find the global optimal solution. Therefore, the method and the technology used in the past are difficult to apply the requirements of the current Rayleigh wave exploration. This study focused on the related technologies and algorithms of F-K domain dispersion curve extraction and GA global non-linear inversion, and combined with the impact of Rayleigh wave data acquisition parameters and the characteristics. Rayleigh wave exploration data processing software design and process technology research is completed. Firstly, the article describes the theoretical basis of Rayleigh wave method. This is also part of the theoretical basis of following treatment. The theoretical proof of existence of Rayleigh wave Dispersive in layered strata. Secondly, F-K domain dispersion curve extraction tests showed that the method can overcome the one-dimensional digital processing technology deficiencies, and make full use of multi-channel Rayleigh wave data record information. GA global non-linear inversion indicated that the inversion is not easy getting into local optimal solution. Thirdly, some examples illustrate each mode Rayleigh wave dispersion curve characteristics in the X-T domain. Tests demonstrated the impact on their extraction of dispersion curves. Parameters change example (including the X
Robert R. Wilson Prize I: Intrabeam Scattering and Touschek Effect
Piwinski, Anton
2017-01-01
Intrabeam scattering and the Touschek effect are explained and compared. Especially intrabeam scattering plays an important role in colliders and synchrotron radiation sources where it limits the beam lifetime and the brightness,respectively. A short history of the consequences of both effects in different accelerators is given. An invariant due to intrabeam scattering is discussed which shows that only below transition energy a stable particle distribution is possible whereas above transition energy a stable distribution cannot exist.
Andersen, Kurt Munk
1997-01-01
Rayleigh's principle expresses that the smallest eigenvalue of a regular Sturm-Liouville problem with regular boundary conditions is the minimum value of a certain functional, the so called Rayleigh's quotient, and that this value is attained at the corresponding eigenfunctions only. This can...... be proved by means of more advanced methods. However, it turns out that there is an elementary proof, which is presented in the report....
Rotating Rayleigh-Taylor turbulence
Boffetta, G.; Mazzino, A.; Musacchio, S.
2016-09-01
The turbulent Rayleigh-Taylor system in a rotating reference frame is investigated by direct numerical simulations within the Oberbeck-Boussinesq approximation. On the basis of theoretical arguments, supported by our simulations, we show that the Rossby number decreases in time, and therefore the Coriolis force becomes more important as the system evolves and produces many effects on Rayleigh-Taylor turbulence. We find that rotation reduces the intensity of turbulent velocity fluctuations and therefore the growth rate of the temperature mixing layer. Moreover, in the presence of rotation the conversion of potential energy into turbulent kinetic energy is found to be less effective, and the efficiency of the heat transfer is reduced. Finally, during the evolution of the mixing layer we observe the development of a cyclone-anticyclone asymmetry.
Gilmore, R. E.; Eagle, R.; Ries, J. B.; Tripati, A. K.
2013-05-01
have different chemical and ionic properties (atomic mass, ionic radius, charge), and these properties impact the frequency that an element is incorporated into the CaCO3 lattice. A Rayleigh model allows us to determine at what point during calcification an element is assimilated into the CaCO3 lattice: whether it is incorporated even when there is abundant calcium in solution, or not incorporated until calcium is nearly depleted. The effect of CO2- and temperature-induced changes in calcification rate on element partitioning in these organisms will be examined to determine if these biogenic calcification systems conform to a Rayleigh model.
Deharak, B. A.; Savich, J. L.; Roberts, H. M.; Brown, E. G.; McGill, M. R.; Kim, B. N.; Weaver, C. M.; Martin, N. L. S.
2016-05-01
We have conducted a series of Monte Carlo simulations of laser assisted free-free scattering experiments. The simulations make use of Kroll-Watson approximation to account for the effects of the laser field on the scattering process. The parameters for these simulations are believed to mimic the experimental conditions of the work reported by Wallbank and Holmes, particularly the target number density. The simulations account for the effects multiple scattering (i.e., the scattering of a single incident electron from multiple target atoms). We present a comparison of the results of these simulations to the experimental results of Wallbank and Holmes. This work was supported by the National Science Foundation under Grants Nos. PHY-0855040 (NLSM) and PHY-1402899 (BAd).
Study of multiple scattering effects in heavy ion RBS
Fang, Z.; O`Connor, D.J. [Newcastle Univ., NSW (Australia). Dept. of Physics
1996-12-31
Multiple scattering effect is normally neglected in conventional Rutherford Backscattering (RBS) analysis. The backscattered particle yield normally agrees well with the theory based on the single scattering model. However, when heavy incident ions are used such as in heavy ion Rutherford backscattering (HIRBS), or the incident ion energy is reduced, multiple scattering effect starts to play a role in the analysis. In this paper, the experimental data of 6MeV C ions backscattered from a Au target are presented. In measured time of flight spectrum a small step in front of the Au high energy edge is observed. The high energy edge of the step is about 3.4 ns ahead of the Au signal which corresponds to an energy {approx} 300 keV higher than the 135 degree single scattering energy. This value coincides with the double scattering energy of C ion undergoes two consecutive 67.5 degree scattering. Efforts made to investigate the origin of the high energy step observed lead to an Monte Carlo simulation aimed to reproduce the experimental spectrum on computer. As a large angle scattering event is a rare event, two consecutive large angle scattering is extremely hard to reproduce in a random simulation process. Thus, the simulation has not found a particle scattering into 130-140 deg with an energy higher than the single scattering energy. Obviously faster algorithms and a better physical model are necessary for a successful simulation. 16 refs., 3 figs.
Azimuthal effects in grazing surface scattering
Robin, A. E-mail: arobin@uos.de; Jensen, J.; Heiland, W
2003-06-01
We report on surface scattering experiments in the MeV regime. N{sup q+} (q=1, 2) ions with 0.7-1.4 MeV are scattered off a single-crystalline Pt(110)(1x2) surface under grazing incidence and specular reflection geometry. We investigate the energy loss dependency on the azimuthal angle under variation of the perpendicular energy.
van der Poel, Erwin P; Ostilla-Mónico, Rodolfo; Verzicco, Roberto; Lohse, Detlef
2014-07-01
The effect of various velocity boundary condition is studied in two-dimensional Rayleigh-Bénard convection. Combinations of no-slip, stress-free, and periodic boundary conditions are used on both the sidewalls and the horizontal plates. For the studied Rayleigh numbers Ra between 10(8) and 10(11) the heat transport is lower for Γ=0.33 than for Γ=1 in case of no-slip sidewalls. This is, surprisingly, the opposite for stress-free sidewalls, where the heat transport increases for a lower aspect ratio. In wider cells the aspect-ratio dependence is observed to disappear for Ra ≥ 10(10). Two distinct flow types with very different dynamics can be seen, mostly dependent on the plate velocity boundary condition, namely roll-like flow and zonal flow, which have a substantial effect on the dynamics and heat transport in the system. The predominantly horizontal zonal flow suppresses heat flux and is observed for stress-free and asymmetric plates. Low aspect-ratio periodic sidewall simulations with a no-slip boundary condition on the plates also exhibit zonal flow. In all the other cases, the flow is roll like. In two-dimensional Rayleigh-Bénard convection, the velocity boundary conditions thus have large implications on both roll-like and zonal flow that have to be taken into consideration before the boundary conditions are imposed.
Evaluation of Influence of Multiple Scattering Effect in Light-Scattering-Based Applications
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.
Scatterers shape effect on speckle patterns
Denisenkov, Valentin S.; Kiyko, Vadim V.; Vdovin, Gleb V.
2015-03-01
Laser speckle analysis is a very powerful method with various existing applications, including biomedical diagnostics. The majority of the speckle applications are based on analysis of dependence of scattered light intensity distribution from sizes of the scattereres. We propose a numerical model of speckle formation in reflected light in one-dimension which shows that properties of the scattered light are strongly dependent on the form of the scatterers. In particular, the dependence of number of speckles from the size of the scatterers was investigated for the light reflected from the surface with varying roughness; the single roughness on the surface was assumed to have the form of one-dimensional `pyramid' with the sides having either linear or parabolic descent from the top of the `pyramid' to the bottom. It was found that for the linear roughness, number of speckles decreased with increase of the roughness size, whereas for the parabolic roughness the number of speckles increased. Results of numerical simulation were compared with experiment investigations of roughness samples (0.5-2.5 μm) made of glass and copper. Due to different production processes, the glass samples are likely to have the parabolic roughness and copper samples are likely to have the linear roughness. Experiments show that the dependences of number of speckles also have different slopes, the same as in numerical simulation. These findings can lead to new analytical methods capable of determining not only the size distribution of roughness (or scatterers) but also the shape.
Scattering approach to quantum transport and many body effects
Pichard, Jean-Louis; Freyn, Axel
2010-12-01
We review a series of works discussing how the scattering approach to quantum transport developed by Landauer and Buttiker for one body elastic scatterers can be extended to the case where electron-electron interactions act inside the scattering region and give rise to many body scattering. Firstly, we give an exact numerical result showing that at zero temperature a many body scatterer behaves as an effective one body scatterer, with an interaction dependent transmission. Secondly, we underline that this effective scatterer depends on the presence of external scatterers put in its vicinity. The implications of this non local scattering are illustrated studying the conductance of a quantum point contact where electrons interact with a scanning gate microscope. Thirdly, using the numerical renormalization group developed by Wilson for the Kondo problem, we study a double dot spinless model with an inter-dot interaction U and inter-dot hopping td, coupled to leads by hopping terms tc. We show that the quantum conductance as a function of td is given by a universal function, independently of the values of U and tc, if one measures td in units of a characteristic scale τ(U,tc). Mapping the double dot system without spin onto a single dot Anderson model with spin and magnetic field, we show that τ(U,tc) = 2TK, where TK is the Kondo temperature of the Anderson model.
韩权; 田丽; 王晓源; 杨晓慧; 杨龙虎
2012-01-01
In pH5. 5 ~6. 5 Britton-Robinson buffer media,a compound complex was formed between Dermatan Sulfate( DS)and Ethyl Violet( EV) .leading to a great enhancement of the intensity of resonance rayleigh scattering( RRS)and giving a new RRS spectrum. The maximum scattering peak is located at 498 nm and two relatively weaker peaks are located at 327 nm and 650 ma. It was also found that the intensity of RRS was directly proportional to the concentration of DS in the range of 0 ~ I. 6 mg/L. Based on these facts,a sensitive method for the determination of DS was proposed. The detection limit of this method was found to be 5. 0 ng/ mL Good selectivity of the method was shown by the results of interference test. The proposed method has been used for the determination of total amounts of dermatan sulfate in urine and blood samples with satisfactory results.%在pH5.5～6.5的Britton-Robinson缓冲溶液中,乙基紫与硫酸皮肤素作用形成结合产物时将导致溶液共振瑞利散射(RRS)显著增强并产生新的RRS光谱,其最大散射峰位于498 nm处,另在327 nm和650 nm处有两个强度较小的散射峰.硫酸皮肤素浓度在0～1.6 mg/L范围内,与RRS强度有良好的线性关系.据此,建立了一种测定硫酸皮肤素的分析方法.该法具有高灵敏度,对硫酸皮肤素的检出限为5.0 ng/mL,选择性良好.应用于尿样和血清中硫酸皮肤素的测定,结果令人满意.
Arabi, Pouria; Jafarpur, Khosrow
2016-08-01
In the present study, effect of different flow regimes on free convection heat transfer has been examined. In the light of this, a novel analytical method is developed to calculate free convection heat transfer from isothermal convex bodies with arbitrary shape over all range of Rayleigh number in fluids with any Prandtl number. The crux of this method is based on the concept of dynamic behaviors existing in natural convection flow. In the previous models the Body Gravity Function (BGF) and Turbulent Function (TF) have been taken as constant values. In this study, BGF accounts for the effect of body shape and orientation with respect to gravity vector in laminar free convection. Besides, TF accounts for the impact of Prandtl number, body shape and orientation with regard to gravity vector in turbulent free convection. By contrast, it is shown that these two parameters undergo a change through the variation of Rayleigh number and cannot be considered as a constant. These two parameters are modeled based upon the thermal resistance concept. Moreover, two transition criteria happening in free convection heat transfer will be obtained according to this new analytical method (conduction-laminar and laminar-turbulent transitions). Finally, three models (models 1, 2 and 3) are proposed for calculation free convection heat transfer and present results for ten isothermal convex bodies with various aspect ratios (0.298 ≤ √ A /P ≤ 2.470) have been compared with the available experimental and numerical data. Here, the results of model 2 are almost equal to those of model 3. Also, the results of model 1 are more precise than those of model 3 while the parameters computation of model 1 is more intricate in comparison with model 3. On the one hand, the model 1 has an average difference <6 % vis-à-vis numerical data in entire range of Rayleigh number (laminar and turbulent). On the other hand, the average difference of model 1 is not more than 8 % versus experimental data
Dielectric effects on Thomson scattering in a relativistic magnetized plasma
Bindslev, H.
1991-01-01
the absorption is small. Symmetry between variables relating to incident and scattered fields is demonstrated and shown to be in agreement with the reciprocity relation. Earlier results are confirmed in the cold plasma limit. Significant relativistic effects, of practical importance to the scattering......The effects of the dielectric properties of a relativistic magnetized plasma on the scattering of electromagnetic radiation by fluctuations in electron density are investigated. The origin of the density fluctuations is not considered. Expressions for the scattering cross-section and the scattered...... power accepted by the receiving antenna are derived for a plasma with spatial dispersion. The resulting expressions allow thermal motion to be included in the description of the plasma and remain valid for frequencies of the probing radiation in the region of omega(p) and omega(ce), provided...
Effects of shear elasticity on sea bed scattering: numerical examples.
Ivakin, A N; Jackson, D R
1998-01-01
It is known that marine sediments can support both compressional and shear waves. However, published work on scattering from irregular elastic media has not examined the influence of shear on sea bed scattering in detail. A perturbation model previously developed by the authors for joint roughness-volume scattering is used to study the effects of elasticity for three sea bed types: sedimentary rock, sand with high shear speed, and sand with "normal" shear wave speed. Both bistatic and monostatic cases are considered. For sedimentary rock it is found that shear elasticity tends to increase the importance of volume scattering and decrease the importance of roughness scattering relative to the fluid case. Shear effects are shown to be small for sands.
Effects of cellular fine structure on scattered light pattern.
Liu, Caigen; Capjack, Clarence E
2006-06-01
Biological cells are complex in both morphological and biochemical structure. The effects of cellular fine structure on light scattered from cells are studied by employing a three-dimensional code named AETHER which solves the full set of Maxwell equations by using the finite-difference time-domain method. It is shown that changes in cellular fine structure can cause significant changes in the scattered light pattern over particular scattering angles. These changes potentially provide the possibility for distinguishability of cellular intrastructures. The effects that features of different intrastructure have on scattered light are discussed from the viewpoint of diagnosing cellular fine structure. Finally, we discuss scattered light patterns for lymphocyte-like cells and basophil-like cells.
Universal dimer-dimer scattering in lattice effective field theory
Elhatisari, Serdar; Lee, Dean; Meißner, Ulf-G; Rupak, Gautam
2016-01-01
We consider two-component fermions with short-range interactions and large scattering length. This system has universal properties that are realized in many different fields including atomic, nuclear and particle physics. In the limit of large fermion-fermion scattering length $a_\\mathrm{ff}$ and zero range interaction, all properties of the system scale proportionally with the only length scale $a_\\mathrm{ff}$. We consider the case where there are bound dimers and calculate the scattering phase shifts for the two-dimer system near threshold using lattice effective field theory. From the scattering phase shifts, we extract the universal dimer-dimer scattering length $a_\\mathrm{dd}/a_\\mathrm{ff}=0.645(89)$ and effective range $r_\\mathrm{dd}/a_\\mathrm{ff}=-0.413(79)$.
Analysis of multiple scattering effects in optical Doppler tomography
Yura, H.T.; Thrane, L.; Andersen, Peter E.
2005-01-01
Optical Doppler tomography (ODT) combines Doppler velocimetry and optical coherence tomography (OCT) to obtain high-resolution cross-sectional imaging of particle flow velocity in scattering media such as the human retina and skin. Here, we present the results of a theoretical analysis of ODT where...... multiple scattering effects are included. The purpose of this analysis is to determine how multiple scattering affects the estimation of the depth-resolved localized flow velocity. Depth-resolved velocity estimates are obtained directly from the corresponding mean or standard deviation of the observed...... Doppler frequency spectrum. Thus, in the present analysis, the dependence of the mean and standard deviation of the Doppler shift on the scattering properties of the flowing medium are obtained. Taking the multiple scattering effects into account, we are able to explain previous measurements of depth...
Weiss, Stephan; Zhong, Jin-Qiang; Clercx, Herman J H; Lohse, Detlef; Ahlers, Guenter; 10.1103/PhysRevLett.105.224501
2011-01-01
In turbulent thermal convection in cylindrical samples of aspect ratio \\Gamma = D/L (D is the diameter and L the height) the Nusselt number Nu is enhanced when the sample is rotated about its vertical axis, because of the formation of Ekman vortices that extract additional fluid out of thermal boundary layers at the top and bottom. We show from experiments and direct numerical simulations that the enhancement occurs only above a bifurcation point at a critical inverse Rossby number $1/\\Ro_c$, with $1/\\Ro_c \\propto 1/\\Gamma$. We present a Ginzburg-Landau like model that explains the existence of a bifurcation at finite $1/\\Ro_c$ as a finite-size effect. The model yields the proportionality between $1/\\Ro_c$ and $1/\\Gamma$ and is consistent with several other measured or computed system properties.
Weak phonon scattering effect of twin boundaries on thermal transmission.
Dong, Huicong; Xiao, Jianwei; Melnik, Roderick; Wen, Bin
2016-01-29
To study the effect of twin boundaries on thermal transmission, thermal conductivities of twinned diamond with different twin thicknesses have been studied by NEMD simulation. Results indicate that twin boundaries show a weak phonon scattering effect on thermal transmission, which is only caused by the additional twin boundaries' thermal resistance. Moreover, according to phonon kinetic theory, this weak phonon scattering effect of twin boundaries is mainly caused by a slightly reduced average group velocity.
Weak phonon scattering effect of twin boundaries on thermal transmission
Huicong Dong; Jianwei Xiao; Roderick Melnik; Bin Wen
2016-01-01
To study the effect of twin boundaries on thermal transmission, thermal conductivities of twinned diamond with different twin thicknesses have been studied by NEMD simulation. Results indicate that twin boundaries show a weak phonon scattering effect on thermal transmission, which is only caused by the additional twin boundaries’ thermal resistance. Moreover, according to phonon kinetic theory, this weak phonon scattering effect of twin boundaries is mainly caused by a slightly reduced averag...
Effect of Scatterering on Coherent Anti-Stokes Raman Scattering (CARS) signals
Ranasinghesagara, Janaka C; Piazza, Vincenzo; Potma, Eric O; Venugopalan, Vasan
2016-01-01
We develop a computational framework to examine the factors responsible for scattering-induced distortions of coherent anti-Stokes Raman scattering (CARS) signals in turbid samples. We use the Huygens-Fresnel Wave-based Electric Field Superposition (HF-WEFS) method combined with the radiating dipole approximation to compute the effects of scattering-induced distortions of focal excitation fields on the far-field CARS signal. We analyze the effect of spherical scatterers, placed in the vicinity of the focal volume, on the CARS signal emitted by different objects (2{\\mu}m diameter solid sphere, 2{\\mu}m diameter myelin cylinder and 2{\\mu}m diameter myelin tube). We find that distortions in the CARS signals arise not only from attenuation of the focal field but also from scattering-induced changes in the spatial phase that modifies the angular distribution of the CARS emission. Our simulations further show that CARS signal attenuation can be minimized by using a high numerical aperture condenser. Moreover, unlike...
Nandukumar, Yada
2015-01-01
We investigate oscillatory instability and routes to chaos in Rayleigh-B\\'enard convection of electrically conducting fluids in presence of external horizontal magnetic field. Three dimensional direct numerical simulations (DNS) of the governing equations are performed for the investigation. DNS shows that oscillatory instability is inhibited by the magnetic field. The supercritical Rayleigh number for the onset of oscillation is found to scale with the Chandrasekhar number $\\mathrm{Q}$ as $\\mathrm{Q}^{\\alpha}$ in DNS with $\\alpha = 1.8$ for low Prandtl numbers ($\\mathrm{Pr}$). Most interestingly, DNS shows $\\mathrm{Q}$ dependent routes to chaos for low Prandtl number fluids like mercury ($\\mathrm{Pr} = 0.025$). For low $\\mathrm{Q}$, period doubling routes are observed, while, quasiperiodic routes are observed for high $\\mathrm{Q}$. The bifurcation structure associated with $\\mathrm{Q}$ dependent routes to chaos is then understood by constructing a low dimensional model from the DNS data. The model also shows...
Effect of polarization entanglement in photon-photon scattering
Rätzel, Dennis; Wilkens, Martin; Menzel, Ralf
2017-01-01
It is found that the differential cross section of photon-photon scattering is a function of the degree of polarization entanglement of the two-photon state. A reduced general expression for the differential cross section of photon-photon scattering is derived by applying simple symmetry arguments. An explicit expression is obtained for the example of photon-photon scattering due to virtual electron-positron pairs in quantum electrodynamics. It is shown how the effect in this explicit example can be explained as an effect of quantum interference and that it fits with the idea of distance-dependent forces.
Evaluation of radar multiple scattering effects in Cloudsat configuration
A. Battaglia
2007-01-01
Full Text Available MonteCarlo simulations have been performed to evaluate the importance of multiple scattering effects in co- and cross-polar radar returns for 94 GHz radars in Cloudsat and airborne configurations. Thousands of vertically structured profiles derived from some different cloud resolving models are used as a test-bed. Mie theory is used to derive the single scattering properties of the atmospheric hydrometeors. Multiple scattering effects in the co-polar channel (reflectivity enhancement are particularly elusive, especially in airborne configuration. They can be quite consistent in satellite configurations, like CloudSat, especially in regions of high attenuation and in the presence of highly forward scattering layers associated with snow and graupel particles. When the cross polar returns are analysed [but note that CloudSat does not measure any linear depolarization ratio (LDR hereafter], high LDR values appear both in space and in airborne configurations. The LDR signatures are footprints of multiple scattering effects; although depolarization values as high as −5 dB can be generated including non-spherical particles in single scattering modelling, multiple scattering computations can produce values close to complete depolarization (i.e. LDR=0 dB. Our simulated LDR profiles from an air-borne platform well reproduce, in a simple frame, some experimental observations collected during the Wakasa Bay experiment. Since LDR instrumental uncertainties were not positively accounted for during that experiment, more focused campaigns with air-borne polarimetric radar are recommended. Multiple scattering effects can be important for CloudSat applications like rainfall and snowfall retrievals since single scattering based algorithms will be otherwise burdened by positive biases.
Passive retrieval of Rayleigh waves in disordered elastic media.
Larose, Eric; Derode, Arnaud; Clorennec, Dominique; Margerin, Ludovic; Campillo, Michel
2005-10-01
When averaged over sources or disorder, cross correlation of diffuse fields yields the Green's function between two passive sensors. This technique is applied to elastic ultrasonic waves in an open scattering slab mimicking seismic waves in the Earth's crust. It appears that the Rayleigh wave reconstruction depends on the scattering properties of the elastic slab. Special attention is paid to the specific role of bulk to Rayleigh wave coupling, which may result in unexpected phenomena, such as a persistent time asymmetry in the diffuse regime.
Li, Fangzuo; Liu, Zhiguo; Sun, Tianxi
2016-11-01
This paper presents an alternative analytical method based on the Rayleigh to Compton scattering intensity ratio and effective atomic number for non-destructive identification of vegetable oils using confocal energy dispersive X-ray fluorescence and scattering spectrometry. A calibration curve for the Rayleigh to Compton scattering intensity ratio and effective atomic number was constructed on the basis of a reliable physical model for X-ray scattering. The content of light elements, which are "invisible" using X-ray fluorescence, can be calculated "by difference" from the calibration curve. In this work, we demonstrated the use of this proposed approach to identify complex organic matrices in different vegetable oils with high precision and accuracy.
Refractive effects in 9Be scattering and nuclear rainbow ghosts
Satchler, G. R.; Fulmer, C. B.; Auble, R. L.; Ball, J. B.; Bertrand, F. E.; Erb, K. A.; Gross, E. E.; Hensley, D. C.
1983-08-01
Data for the elastic scattering of 9Be on 12C and 16O at 158 MeV provide evidence of refractive effects that allow the optical potentials to be determined with little ambiguity. The real potentials are deep. Large angle data indicate dominance of negative-angle scattering from the far side of the target nucleus. The analysis also implies a residual rainbow phenomenon, contrary to what has been seen previously in heavy-ion scattering. We suggest this be called a rainbow ghost. Operated by Union Carbide Corporation under contract W-7405-eng-26 with the US Department of Energy.
Isospin effects in elastic proton-nucleus scattering
Chinn, C. R.; Elster, Ch.; Thaler, R. M.
1993-05-01
Isovector effects in proton-nucleus elastic scattering at medium energies are studied. The accuracy of the Kerman-McManus-Thaler isospin averaging procedure is found to be very good for nuclei larger than 4He. Studies of 40Ca and 208Pb suggest that the surface neutrons may be pulled in somewhat relative to the protons, although uncertainties in the detailed applicability of the present truncation of the multiple scattering treatment render firm conclusions premature.
Isospin effects in elastic proton-nucleus scattering
Chinn, C.R. (Service de Physique et Techniques Nucleaires, Centre d' Etudes de Bruyeres-le-Chatel, B.P. No. 12, 91680 Bruyeres-le-Chatel (France)); Elster, C. (Institute of Nuclear and Particle Physics and Department of Physics, Ohio University, Athens, Ohio 45701 (United States)); Thaler, R.M. (Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States) Case Western Reserve University, Cleveland, Ohio 44106 (United States))
1993-05-01
Isovector effects in proton-nucleus elastic scattering at medium energies are studied. The accuracy of the Kerman-McManus-Thaler isospin averaging procedure is found to be very good for nuclei larger than [sup 4]He. Studies of [sup 40]Ca and [sup 208]Pb suggest that the surface neutrons may be pulled in somewhat relative to the protons, although uncertainties in the detailed applicability of the present truncation of the multiple scattering treatment render firm conclusions premature.
Effective gravitational fields in transplackian scattering
Betti, Luca S G
2014-01-01
After a short introduction to the general Quantum Gravity problem, we compare a result from the S-matrix description of gravitational interaction due to Amati, Ciafaloni and Veneziano (ACV) with classical General Relativity results. In Chapter 1, we introduce the metric produced by a massless particle moving at the speed of light. In Chapter 2, we review ACV's semiclassical approach to gravitation and show some of its result. In Chapter 3, we detail the computation of gravitational field expectation values in a high-energy scattering process, following ACV's prescriptions. In Chapter 4, we analyze our results. The main feature is that the leading contributions to the metric computed in terms of the Feynman diagrams deriving from ACV's model perfectly reproduce classical results.
Yao, Xiaojun; Müller, Berndt
2016-01-01
We study the dynamical screening effect in the QED plasma on the $\\alpha$-$\\alpha$ scattering at the $^8$Be resonance. Dynamical screening leads to an imaginary part of the potential which results in a thermal width for the resonance and dominates over the previously considered static screening effect. As a result, both the resonance energy and width increase with the plasma temperature. Furthermore, dynamical screening can have a huge impact on the $\\alpha$-$\\alpha$ thermal nuclear scattering rate. For example, when the temperature is around $10$ keV, the rate is suppressed by a factor of about $900$. We expect similar thermal suppressions of nuclear reaction rates to occur in nuclear reactions dominated by an above threshold resonance with a thermal energy. Dynamical screening effects on nuclear reactions can be relevant to cosmology and astrophysics.
Kurudirek, Murat
2016-11-01
The objective of this work was to study water- and tissue-equivalent properties of some gel dosimeters, human tissues and water, for scattering of photons using the effective atomic number (Z eff). The Rayleigh to Compton scattering ratio (R/C) was used to obtain Z eff and electron density (N e ) of gel dosimeters, human tissues and water considering a 10(-2)-10(9) momentum transfer, q (Å(-1)). In the present work, a logarithmic interpolation procedure was used to estimate R/C as well as Z eff of the chosen materials in a wide scattering angle (1°-180°) and energy range (0.001-100 MeV). The Z eff of the chosen materials was found to increase as momentum transfer increases, for q > ~1 Å(-1). At fixed scattering angle and energy, Z eff of the material first increases and then becomes constant for high momentum transfers (q ≥ 3 Å(-1)), which indicates that Z eff is almost independent of energy and scattering angle for the chosen materials. Based on the Z eff data and the continuous momentum transfer range (10(-2)-10(9) Å(-1)), MAGIC, PAGAT and soft tissue were found to be water-equivalent materials, since their differences (%) relative to water are significantly low (≤3.2 % for MAGIC up to 10(3) Å(-1), ≤2.9 % for PAGAT up to 10(9) Å(-1), and ≤3.8 % for soft tissue up to 10(9) Å(-1)), while the Fricke gel was not found to be water equivalent. PAGAT was found to be a soft tissue-equivalent material in the entire momentum transfer range (<4.3 %), while MAGAT has shown to be tissue equivalent for brain (≤8.1 % up to 10 Å(-1)) and lung (<8.2 % up to 10 Å(-1)) tissues. The Fricke gel dosimeter has shown to be adipose tissue equivalent for most of the momentum range considered (<10 %).
Relativistic effects in elastic scattering of electrons in TEM.
Rother, Axel; Scheerschmidt, Kurt
2009-01-01
Transmission electron microscopy typically works with highly accelerated thus relativistic electrons. Consequently the scattering process is described within a relativistic formalism. In the following, we will examine three different relativistic formalisms for elastic electron scattering: Dirac, Klein-Gordon and approximated Klein-Gordon, the standard approach. This corresponds to a different consideration of spin effects and a different coupling to electromagnetic potentials. A detailed comparison is conducted by means of explicit numerical calculations. For this purpose two different formalisms have been applied to the approaches above: a numerical integration with predefined boundary conditions and the multislice algorithm, a standard procedure for such simulations. The results show a negligibly small difference between the different relativistic equations in the vicinity of electromagnetic potentials, prevailing in the electron microscope. The differences between the two numeric approaches are found to be small for small-angle scattering but eventually grow large for large-angle scattering, recorded for instance in high-angle annular dark field.
van der Poel, Erwin P; Verzicco, Roberto; Lohse, Detlef
2015-01-01
The effect of various velocity boundary condition is studied in two-dimensional Rayleigh-B\\'enard convection. Combinations of no-slip, stress-free and periodic boundary conditions are used on both the sidewalls and the horizontal plates. For the studied Rayleigh numbers Ra between $10^8$ and $10^{11}$ the heat transport is lower for $\\Gamma = 0.33$ than for $\\Gamma = 1$ in case of no-slip sidewalls. This is surprisingly opposite for stress-free sidewalls, where the heat transport increases for lower aspect-ratio. In wider cells the aspect-ratio dependence is observed to disappear for $\\text{Ra} \\ge 10^{10}$. Two distinct flow types with very different dynamics can be seen, mostly dependent on the plate velocity boundary condition, namely roll-like flow and horizontal zonal flow, which have a substantial effect on the dynamics and heat transport in the system. The predominantly horizontal zonal flow suppresses heat flux and is observed for stress-free and asymmetric plates. Low aspect-ratio periodic sidewall s...
Measuring the effect of rounding the corners of scattering structures
Markowskei, Audrey J.; Smith, Paul D.
2017-05-01
In studying acoustic or electromagnetic wave diffraction, the choice of an appropriate canonical structure to model the dominant features of a scattering scenario can be very illuminating. A common approach used when dealing with domains with corners is to round the corners, producing a smooth surface, eliminating the singularities introduced by the corners. In order to quantify the effect of corner rounding, this paper examines the diffraction from cylindrical scatterers which possess corners, that is, points at which the normal changes discontinuously. We develop a numerical method for the scattering of a plane wave normally incident on such cylindrical structures with soft, hard, or impedance loaded boundary conditions. We then examine the difference between various test structures with corners and with the corners rounded to assess the impact on near- and far-field scattering, as a function of the radius of curvature in the vicinity of the rounded corner point. We then examine the nature of the differences in the far field between the cornered and rounded scatterers as well as the effect on the differences as the frequency of the plane wave increases and obtain precise quantitative estimates for the rate of convergence of the maximum difference between the far-field solutions as the radius of curvature of the rounded scatterer approaches zero.
Chromo-Rayleigh Interactions of Dark Matter
Bai, Yang
2015-01-01
For a wide range of models, dark matter can interact with QCD gluons via chromo-Rayleigh interactions. We point out that the Large Hadron Collider (LHC), as a gluon machine, provides a superb probe of such interactions. In this paper, we introduce simplified models to UV-complete two effective dark matter chromo-Rayleigh interactions and identify the corresponding collider signatures, including four jets or a pair of di-jet resonances plus missing transverse energy. After performing collider studies for both the 8 TeV and 14 TeV LHC, we find that the LHC can be more sensitive to dark matter chromo-Rayleigh interactions than direct detection experiments and thus provides the best opportunity for future discovery of this class of models.
Antoniassi, M.; Conceicao, A.L.C.; Poletti, M.E. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Fac. de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica
2010-07-01
The scattered radiation has been used in several industrial and clinical applications since it permits to characterize the scattering material. Several types of information can be extracted from the spectrum of scattered radiation which can be used to characterization of biological tissues such as breast tissues. In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose), benign (fibroadenoma) and malignant (carcinoma) neoplastic breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90 deg C (x = 0.99 angstrom-1). A practical method using the area of elastic and inelastic scattering was used for determining the effective atomic number (Z{sub eff}) of the samples, being validated comparing the experimental obtained values of Z{sub eff} of several standard materials with calculated values using traditional method based on total cross-section of compounds. The obtained results show that exist differences in the distributions of Z{sub eff} of breast tissues, which are related to the content of carbon (Z=6) and oxygen (Z=8) in each tissue type. The results suggest that is possible to use this parameter for characterizing breast tissues, pointing the possibility of its use as a complementary tool for the diagnosis of the breast cancer. (author)
Effective Tree Scattering and Opacity at L-Band
Kurum, Mehmet; O'Neill, Peggy E.; Lang, Roger H.; Joseph, Alicia T.; Cosh, Michael H.; Jackson, Thomas J.
2011-01-01
This paper investigates vegetation effects at L-band by using a first-order radiative transfer (RT) model and truck-based microwave measurements over natural conifer stands to assess the applicability of the tau-omega) model over trees. The tau-omega model is a zero-order RT solution that accounts for vegetation effects with effective vegetation parameters (vegetation opacity and single-scattering albedo), which represent the canopy as a whole. This approach inherently ignores multiple-scattering effects and, therefore, has a limited validity depending on the level of scattering within the canopy. The fact that the scattering from large forest components such as branches and trunks is significant at L-band requires that zero-order vegetation parameters be evaluated (compared) along with their theoretical definitions to provide a better understanding of these parameters in the retrieval algorithms as applied to trees. This paper compares the effective vegetation opacities, computed from multi-angular pine tree brightness temperature data, against the results of two independent approaches that provide theoretical and measured optical depths. These two techniques are based on forward scattering theory and radar corner reflector measurements, respectively. The results indicate that the effective vegetation opacity values are smaller than but of similar magnitude to both radar and theoretical estimates. The effective opacity of the zero-order model is thus set equal to the theoretical opacity and an explicit expression for the effective albedo is then obtained from the zero- and first- order RT model comparison. The resultant albedo is found to have a similar magnitude as the effective albedo value obtained from brightness temperature measurements. However, it is less than half of that estimated using the theoretical calculations (0.5 - 0.6 for tree canopies at L-band). This lower observed albedo balances the scattering darkening effect of the large theoretical albedo
An Effective Field Theory for Forward Scattering and Factorization Violation
Rothstein, Ira Z
2016-01-01
Starting with QCD, we derive an effective field theory description for forward scattering and factorization violation as part of the soft-collinear effective field theory (SCET) for high energy scattering. These phenomena are mediated by long distance Glauber gluon exchanges, which are static in time, localized in the longitudinal distance, where $|t| \\ll s$. In hard scattering, Glauber gluons can induce corrections which invalidate factorization. With SCET, Glauber exchange graphs can be calculated explicitly, and are distinct from graphs with soft, collinear, or ultrasoft gluons. We derive a complete basis of operators which describe the leading power effects of Glauber exchange. Key ingredients include regulating light-cone rapidity singularities and subtractions which prevent double counting. Our results include a novel all orders gauge invariant pure glue soft operator which appears between two collinear rapidity sectors. The 1-gluon Feynman rule for the soft operator coincides with the Lipatov vertex, b...
Revisiting the scattering greenhouse effect of CO2 ice clouds
Kitzmann, Daniel
2016-01-01
Carbon dioxide ice clouds are thought to play an important role for cold terrestrial planets with thick CO2 dominated atmospheres. Various previous studies showed that a scattering greenhouse effect by carbon dioxide ice clouds could result in a massive warming of the planetary surface. However, all of these studies only employed simplified two-stream radiative transfer schemes to describe the anisotropic scattering. Using accurate radiative transfer models with a general discrete ordinate method, this study revisits this important effect and shows that the positive climatic impact of carbon dioxide clouds was strongly overestimated in the past. The revised scattering greenhouse effect can have important implications for the early Mars, but also for planets like the early Earth or the position of the outer boundary of the habitable zone.
Shiels, C.; Butler, S. L.
2015-09-01
Mantle convection models with a low viscosity asthenosphere and high viscosity surface plates have been shown to produce very large aspect ratio convection cells like those inferred to exist in Earth's mantle and to exhibit two asthenospheric flow regimes. When the surface plate is highly mobile, the plate velocity exceeds the flow velocities in the asthenosphere and the plate drives a Couette-type flow in the asthenospheric channel. For sluggish plates, the flow velocities in the asthenosphere exceed the plate velocity and the asthenospheric flow is more Poiseuille-like. It has been shown that under certain circumstances, flows become increasingly Couette-like as the aspect ratio of the plate is increased in numerical simulations. These models also show an increase in the average surface heat flux with aspect ratio which is counterintuitive, as one would expect that large aspect ratio models would result in older and colder oceanic lithosphere. Previous investigations have used single internal heating rates and Rayleigh numbers and a plate formulation that did not preclude significant deformation within the plate. In this paper, we investigate the conditions necessary for Couette and Poiseuille asthenospheric flows and for surface heat flux to increase with plate aspect ratio by varying the internal heating rate, the Rayleigh number and the representation of surface plates in 2D mantle convection models Plates are represented as a high viscosity layer with (1) a free-slip top surface boundary condition and (2) a force-balance boundary condition that imposes a constant surface velocity within the plate. We find that for models with a free-slip surface boundary condition, the internal heating rate and Rayleigh number do not strongly affect the dominance of Couette or Poiseuille flows in the asthenosphere but the increase in surface heat flux with model aspect ratio in the Poiseuille asthenospheric flow regime increases with internal heating rate. For models using
Multiple photon effects in $pp$ scattering at SSC energies
Delaney, D B; Shio, C; Siopsis, G; Ward, B F L
1992-01-01
The Monte Carlo program SSCYFS2 is used in conjunction with available parton distribution functions to calculate the effects of multiple photon radiation on pp scattering at SSC energies. Effects relevant to precision SSC physics such as Higgs discovery and exploration are illustrated.
Coulomb distortion effects in deep-inelastic electron scattering
Co', Giampaolo; Heisenberg, Jochen
1987-11-01
The effects of the Coulomb distortion of the electron wave functions in the description of the electron scattering processes in the quasi-elastic region are discussed. A method to extract longitudinal and transverse response functions considering these effects is presented. While the transverse response function is remarkably affected by the Coulomb distortion, the values of the longitudinal response function are practically unchanged.
Homogeneous illusion device exhibiting transformed and shifted scattering effect
Mei, Jin-Shuo; Wu, Qun; Zhang, Kuang; He, Xun-Jun; Wang, Yue
2016-06-01
Based on the theory of transformation optics, a type of homogeneous illusion device exhibiting transformed and shifted scattering effect is proposed in this paper. The constitutive parameters of the proposed device are derived, and full-wave simulations are performed to validate the electromagnetic properties of transformed and shifted scattering effect. The simulation results show that the proposed device not only can visually shift the image of target in two dimensions, but also can visually transform the shape of target. It is expected that such homogeneous illusion device could possess potential applications in military camouflage and other field of electromagnetic engineering.
Scattering from Star Polymers including Excluded Volume Effects
Li, Xin; Liu, Yun; Sánchez-Diáz, Luis E; Hong, Kunlun; Smith, Gregory S; Chen, Wei-Ren
2014-01-01
In this work we present a new model for the form factor of a star polymer consisting of self-avoiding branches. This new model incorporates excluded volume effects and is derived from the two point correlation function for a star polymer.. We compare this model to small angle neutron scattering (SANS) measurements from polystyrene (PS) stars immersed in a good solvent, tetrahydrofuran (THF). It is shown that this model provides a good description of the scattering signature originating from the excluded volume effect and it explicitly elucidates the connection between the global conformation of a star polymer and the local stiffness of its constituent branch.
The Aharonov--Bohm effect in scattering theory
Sitenko, Yu A
2013-01-01
The Aharonov--Bohm effect is considered as a scattering event with nonrelativistic charged particles of the wavelength which is less than the transverse size of an impenetrable magnetic vortex. The quasiclassical WKB method is shown to be efficient in solving this scattering problem. We find that the scattering cross section consists of two terms, one describing the classical phenomenon of elastic reflection and another one describing the quantum phenomenon of diffraction; the Aharonov--Bohm effect is manifested as a fringe shift in the diffraction pattern. Both the classical and the quantum phenomena are independent of the choice of a boundary condition at the vortex edge, providing that probability is conserved. We show that a propagation of charged particles can be controlled by altering the flux of a magnetic vortex placed on their way.
Gagnon, Alexander C.; Adkins, Jess F.; Fernandez, Diego P.; Robinson, Laura F.
2007-09-01
Deep-sea corals are a new tool in paleoceanography with the potential to provide century long records of deep ocean change at sub-decadal resolution. Complicating the reconstruction of past deep-sea temperatures, Mg/Ca and Sr/Ca paleothermometers in corals are also influenced by non-environmental factors, termed vital effects. To determine the magnitude, pattern and mechanism of vital effects we measure detailed collocated Sr/Ca and Mg/Ca ratios, using a combination of micromilling and isotope-dilution ICP-MS across skeletal features in recent samples of Desmophyllum dianthus, a scleractinian coral that grows in the near constant environment of the deep-sea. Sr/Ca variability across skeletal features is less than 5% (2σ relative standard deviation) and variability of Sr/Ca within the optically dense central band, composed of small and irregular aragonite crystals, is significantly less than the surrounding skeleton. The mean Sr/Ca of the central band, 10.6 ± 0.1 mmol/mol (2σ standard error), and that of the surrounding skeleton, 10.58±0.09 mmol/mol, are statistically similar, and agree well with the inorganic aragonite Sr/Ca-temperature relationship at the temperature of coral growth. In the central band, Mg/Ca is greater than 3 mmol/mol, more than twice that of the surrounding skeleton, a general result observed in the relative Mg/Ca ratios of D. dianthus collected from separate oceanographic locations. This large vital effect corresponds to a ˜ 10 °C signal, when calibrated via surface coral Mg/Ca-temperature relationships, and has the potential to complicate paleoreconstructions. Outside the central band, Mg/Ca ratios increase with decreasing Sr/Ca. We explain the correlated behavior of Mg/Ca and Sr/Ca outside the central band by Rayleigh fractionation from a closed pool, an explanation that has been proposed elsewhere, but which is tested in this study by a simple and general relationship. We constrain the initial solution and effective partition
Xia, Haiyun; Dou, Xiankang; Shangguan, Mingjia; Zhao, Ruocan; Sun, Dongsong; Wang, Chong; Qiu, Jiawei; Shu, Zhifeng; Xue, Xianghui; Han, Yuli; Han, Yan
2014-09-08
Temperature detection remains challenging in the low stratosphere, where the Rayleigh integration lidar is perturbed by aerosol contamination and ozone absorption while the rotational Raman lidar is suffered from its low scattering cross section. To correct the impacts of temperature on the Rayleigh Doppler lidar, a high spectral resolution lidar (HSRL) based on cavity scanning Fabry-Perot Interferometer (FPI) is developed. By considering the effect of the laser spectral width, Doppler broadening of the molecular backscatter, divergence of the light beam and mirror defects of the FPI, a well-behaved transmission function is proved to show the principle of HSRL in detail. Analysis of the statistical error of the HSRL is carried out in the data processing. A temperature lidar using both HSRL and Rayleigh integration techniques is incorporated into the Rayleigh Doppler wind lidar. Simultaneous wind and temperature detection is carried out based on the combined system at Delhi (37.371°N, 97.374°E; 2850 m above the sea level) in Qinghai province, China. Lower Stratosphere temperature has been measured using HSRL between 18 and 50 km with temporal resolution of 2000 seconds. The statistical error of the derived temperatures is between 0.2 and 9.2 K. The temperature profile retrieved from the HSRL and wind profile from the Rayleigh Doppler lidar show good agreement with the radiosonde data. Specifically, the max temperature deviation between the HSRL and radiosonde is 4.7 K from 18 km to 36 km, and it is 2.7 K between the HSRL and Rayleigh integration lidar from 27 km to 34 km.
The effect of hemolysis on acoustic scattering from blood
Coussios, Constantin-C.; Ffowcs Williams, Shon E.
2002-05-01
In an attempt to develop a direct method for measuring the extent of red cell damage in vitro, the effect of the degree of hemolysis on ultrasonic scattering from blood was investigated. Starting with a suspension of 30% hematocrit, a series of suspensions containing different relative concentrations of healthy and damaged red cells in saline were prepared, with the total number of cells present in any one suspension being constant. For each sample, a suspension of equal concentration of healthy cells, but no lyzed cells, was also produced. Using a specially designed container, all samples were exposed to 15 MHz ultrasound in pulse-echo mode and measurements of backscattering were obtained. At high hematocrits, the samples containing damaged cells were found to scatter substantially more than the suspensions containing exclusively healthy cells. This indicates that damaged cells contribute significantly to the overall backscattered intensity. Below a concentration of 13% per volume of healthy cells, scattering levels from healthy and hemolyzed suspensions were comparable. A theoretical model, which treats healthy cells as weak-scattering spheres and damaged cells as hard thin disks, is proposed to interpret the observed scattering behavior.
Initial Integration of Noise Prediction Tools for Acoustic Scattering Effects
Nark, Douglas M.; Burley, Casey L.; Tinetti, Ana; Rawls, John W.
2008-01-01
This effort provides an initial glimpse at NASA capabilities available in predicting the scattering of fan noise from a non-conventional aircraft configuration. The Aircraft NOise Prediction Program, Fast Scattering Code, and the Rotorcraft Noise Model were coupled to provide increased fidelity models of scattering effects on engine fan noise sources. The integration of these codes led to the identification of several keys issues entailed in applying such multi-fidelity approaches. In particular, for prediction at noise certification points, the inclusion of distributed sources leads to complications with the source semi-sphere approach. Computational resource requirements limit the use of the higher fidelity scattering code to predict radiated sound pressure levels for full scale configurations at relevant frequencies. And, the ability to more accurately represent complex shielding surfaces in current lower fidelity models is necessary for general application to scattering predictions. This initial step in determining the potential benefits/costs of these new methods over the existing capabilities illustrates a number of the issues that must be addressed in the development of next generation aircraft system noise prediction tools.
Sorensen, C.M.
1976-01-01
An effort to expand light-scattering autocorrelation techniques to Brownian diffusional and critical fluid systems in which multiple scattering effects are important, and to understand the observed similarity of the Rayleigh linewidth of light scattered from these two seemingly different systems is discussed. A formalism was developed to find the light field multiply scattered from a suspension of Brownian diffusing particles. For the field doubly scattered from a system of noninteracting Brownian particles, the intensity and correlation time were much less dependent on the scattering angle than for the singly scattered component. The polarized and depolarized correlation times of light scattered from Brownian particle systems were measured. The double-scattering formalism was extended to light scattered from critical fluid systems. In the region k xi greater than 5 the doubly and singly scattered correlation times were nearly equal. The dynamic droplet model of critical phenomena was developed which gives the proper, experimentally verified, forms for the intensity and linewidth of light scattered from a critical fluid. To test the dynamic droplet model and the mode theories Rayleigh linewidth predictions, light-scattering measurements were performed on the critical fluid system methanol and cyclohexane. The data agreed with both the dynamic droplet and decoupled mode theory predictions. The depolarized scattered spectra from a critical fluid were measured, and qualitative agreement with the double-scattering theory was found. 57 figures, 5 tables.
Effect of pyrophosphate on the light scatter in KDP crystal
无
2001-01-01
Pyrophosphate doped potassium dihydrogen phosphate (KDP) crystal was grown from aqueous solution by the temperature lowering method. Light scatter in KDP crystal was detected with the ultramicroscopic method. The light scatter in KDP crystal was aggravated when pyrophosphate was doped into the growth solution, which was distributed ununiformly in prism and pyramidal sectors of KDP crystal. Different effects of pyrophosphate on prism and pyramidal sectors of KDP crystal can explain this case. The transmission in this crystal was measured, showing that pyrophosphate affects the transmission evidently.
Gao Fei; Yamada Ryoko; Watanabe Mitsuo; Liu Hua-Feng
2009-01-01
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.
Proton Elastic Scattering from 14Be and Halo Effects
GU Bai-Ping; REN Zhong-Zhou
2006-01-01
The elastic scattering ofp-14Be system at Elab = 200 MeV is evaluated within the relativistic impulse approximation. We discuss the effects of the halo neutrons on the three observables of the elastic scattering system,such as differential cross section dσ/dΩ, analyzing power Ay and spin rotation Q. The results of the three observables of the elastic scattering of p-14Be system are compared with those of p-12C and p-16O systems at the same energy as Elab = 200 MeV. We have found that in the small angular region the Ay and Q, as well as dσ/dΩ, are quite sensitive to the nucleon density distributions on the surface of the target nucleus and offer some unique behaviors of halo nuclei.
Light scattering of PMMA latex particles in benzene: structural effects
Nieuwenhuis, E.A.; Vrij, A.
1979-01-01
Intra- and interparticle structural effects were studied in polymethylmethacrylate (PMMA) latex dispersions in a nonpolar solvent with the technique of light scattering. The required transparency of the dispersions was attained by a close matching of the refractive index of PMMA and solvent, for whi
Quantum noise memory effect of multiple scattered light
Lodahl, P
2005-01-01
We investigate frequency correlations in multiple scattered light that are present in the quantum fluctuations. The memory effect for quantum and classical noise is compared, and found to have markedly different frequency scaling, which was confirmed in a recent experiment. Furthermore, novel mesoscopic correlations are predicted that depend on the photon statistics of the incoming light.
Scattering effect in proton beam windows at spallation targets
Meng, C; Jing, H T
2010-01-01
Proton beam window (PBW) is a boundary wall between a high vacuum area in the proton beam line and the helium atmosphere in a helium vessel at a high beam power target. The thermal and mechanical problems of the PBW have been studied in other spallation neutron sources; however, the scattering effect in PBW is seldom reported in literature but it may pose serious problems for the target design if not well treated. This paper will report the simulation studies of the scattering effect in PBW. Different materials and different structures of PBW are discussed. Taking CSNS as an example, a thin single-layer aluminum alloy PBW with edge cooling has been chosen for CSNS-I and CSNS-II, and a sandwiched aluminum alloy PBW has been chosen for CSNS-III. Simulations results of the scattering effect in the presence of beam uniformization at target by using non-linear magnets at the different CSNS PBWs are presented. The simulations show that the scattering effect at PBW is very important in the beam loss and the beam dis...
Molecule scattering from solid surfaces : Orientation and surface corrugation effects
Vicanek, M; Schlatholter, T; Heiland, W
1997-01-01
Various effects connected with orientation and surface corrugation in molecule scattering from solid surfaces are investigated by means of classical trajectories simulations for H-2 impinging on Pd(110). Primary excitation of the projectiles is modeled according to the situation in molecular beam ex
Terrestrial effects on dark matter-electron scattering experiments
Emken, Timon; Kouvaris, Chris; Shoemaker, Ian M.
2017-01-01
techniques involving detection of dark matter-electron scattering offer new sensitivity to sub-GeV dark matter. Typically however it is implicitly assumed that the dark matter is not altered as it traverses the Earth to arrive at the detector. In this paper we study in detail the effects of terrestrial...
Effective single scattering albedo estimation using regional climate model
Tesfaye, M
2011-09-01
Full Text Available In this study, by modifying the optical parameterization of Regional Climate model (RegCM), the authors have computed and compared the Effective Single-Scattering Albedo (ESSA) which is a representative of VIS spectral region. The arid, semi...
Herschbach, Christian; Fedorov, Dmitry V.; Mertig, Ingrid; Gradhand, Martin; Chadova, Kristina; Ebert, Hubert; Ködderitzsch, Diemo
2013-11-01
We present a detailed analysis of the skew-scattering contribution to the spin Hall conductivity using an extended version of the resonant scattering model of Fert and Levy [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.106.157208 106, 157208 (2011)]. For 5d impurities in a Cu host, the proposed phase shift model reproduces the corresponding first-principles calculations. Crucial for that agreement is the consideration of two scattering channels related to p and d impurity states since the discussed mechanism is governed by a subtle interplay between the spin-orbit and potential scattering in both angular-momentum channels. It is shown that the potential scattering strength plays a decisive role for the magnitude of the spin Hall conductivity.
An effective field theory for forward scattering and factorization violation
Rothstein, Ira Z.; Stewart, Iain W.
2016-08-01
Starting with QCD, we derive an effective field theory description for forward scattering and factorization violation as part of the soft-collinear effective field theory (SCET) for high energy scattering. These phenomena are mediated by long distance Glauber gluon exchanges, which are static in time, localized in the longitudinal distance, and act as a kernel for forward scattering where | t| ≪ s. In hard scattering, Glauber gluons can induce corrections which invalidate factorization. With SCET, Glauber exchange graphs can be calculated explicitly, and are distinct from graphs involving soft, collinear, or ultrasoft gluons. We derive a complete basis of operators which describe the leading power effects of Glauber exchange. Key ingredients include regulating light-cone rapidity singularities and subtractions which prevent double counting. Our results include a novel all orders gauge invariant pure glue soft operator which appears between two collinear rapidity sectors. The 1-gluon Feynman rule for the soft operator coincides with the Lipatov vertex, but it also contributes to emissions with ≥ 2 soft gluons. Our Glauber operator basis is derived using tree level and one-loop matching calculations from full QCD to both SCETII and SCETI. The one-loop amplitude's rapidity renormalization involves mixing of color octet operators and yields gluon Reggeization at the amplitude level. The rapidity renormalization group equation for the leading soft and collinear functions in the forward scattering cross section are each given by the BFKL equation. Various properties of Glauber gluon exchange in the context of both forward scattering and hard scattering factorization are described. For example, we derive an explicit rule for when eikonalization is valid, and provide a direct connection to the picture of multiple Wilson lines crossing a shockwave. In hard scattering operators Glauber subtractions for soft and collinear loop diagrams ensure that we are not sensitive to
Modelling Nuclear Effects in Neutrino Scattering
Leitner, T; Mosel, U
2006-01-01
We have developed a model to describe the interactions of neutrinos with nucleons and nuclei via charged and neutral currents, focusing on the region of the quasielastic and Delta(1232) peaks. For neutrino nucleon collisions a fully relativistic formalism is used. The extension to finite nuclei has been done in the framework of a coupled-channel BUU transport model where we have studied exclusive channels taking into account in-medium effects and final state interactions.
Ridouane, El Hassan; Hasnaoui, Mohammed; Campo, Antonio
2006-01-01
Coupled laminar natural convection with radiation in air-filled square enclosure heated from below and cooled from above is studied numerically for a wide variety of radiative boundary conditions at the sidewalls. A numerical model based on the finite difference method was used for the solution of mass, momentum and energy equations. The surface-to-surface method was used to calculate the radiative heat transfer. Simulations were performed for two values of the emissivities of the active and insulated walls (ɛ1=0.05 or 0.85, ɛ2=0.05 or 0.85) and Rayleigh numbers ranging from 103 to 2.3×106 . The influence of those parameters on the flow and temperature patterns and heat transfer rates are analyzed and discussed for different steady-state solutions. The existing ranges of these solutions are reported for the four different cases considered. It is founded that, for a fixed Ra, the global heat transfer across the enclosure depends only on the magnitude of the emissivity of the active walls. The oscillatory behavior, characterizing the unsteady-state solutions during the transitions from bicellular flows to the unicellular flow are observed and discussed.
Yeh, Chien-Hung; Chow, Chi-Wai
2016-05-16
In this investigation, we demonstrate a new colorless orthogonal-frequency-division-multiplexing (OFDM) wavelength-division-multiplexing passive optical network (WDM-PON) system with Rayleigh backscattering (RB) noise mitigation. Here, only a single laser source at the central office (CO) is needed to produce the downstream signal and distributed continuous-wave (CW) carrier, which will then be modulated at the optical networking unit (ONU) to produce the upstream signal. Single side-band (SSB) modulation is used to wavelength-shift the distributed CW carrier, which will be launched into a reflective semiconductor optical amplifier (RSOA) based ONU for directly modulation of 5.15 Gbps OFDM upstream signal. To avoid the radio-frequency (RF) power fading and chromatic fiber dispersion, the four-band OFDM modulation is proposed to generate a 40 Gbps downstream when a Mach-Zehnder modulator (MZM) with -0.7 chirp parameter is used. Hence, the RB circumvention can be centralized in the CO. Moreover, the signal performances of downstream and upstream are also studied and discussed in this measurement.
Thompson, Laird A.; Teare, Scott W.
2002-09-01
Laser guide stars created by Rayleigh scattering provide a reasonable means to monitor atmospheric wavefront distortions for real-time correction by adaptive optics systems. Because of the λ-4 wavelength dependence of Rayleigh scattering, short-wavelength lasers are a logical first choice for astronomical laser guide star systems, and in this paper we describe the results from a sustained experimental effort to integrate into an adaptive optics system a 351 nm Rayleigh laser guide star created at an altitude of 20 km (above mean sea level) at the Mount Wilson 2.5 m telescope. In addition to providing obvious scientific benefits, the 351 nm laser guide star projected by the University of Illinois Seeing Improvement System is ``stealth qualified'' in terms of the Federal Aviation Administration and airplane avoidance. Because of the excellent return signal at the wavefront sensor, there is no doubt that future applications will be found for short-wavelength Rayleigh-scattered laser guide stars.
A parallel architecture for interactively rendering scattering and refraction effects.
Bernabei, Daniele; Hakke-Patil, Ajit; Banterle, Francesco; Di Benedetto, Marco; Ganovelli, Fabio; Pattanaik, Sumanta; Scopigno, Roberto
2012-01-01
A new method for interactive rendering of complex lighting effects combines two algorithms. The first performs accurate ray tracing in heterogeneous refractive media to compute high-frequency phenomena. The second applies lattice-Boltzmann lighting to account for low-frequency multiple-scattering effects. The two algorithms execute in parallel on modern graphics hardware. This article includes a video animation of the authors' real-time algorithm rendering a variety of scenes.
Longwave scattering effects on fluxes in broken cloud fields
Takara, E.E.; Ellingson, R.G. [Univ. of Maryland, College Park, MD (United States)
1996-04-01
The optical properties of clouds in the radiative energy balance are important. Most works on the effects of scattering have been in the shortwave; but longwave effects can be significant. In this work, the fluxes above and below a single cloud layer are presented, along with the errors in assuming flat black plate clouds or black clouds. The predicted fluxes are the averaged results of analysis of several fields with the same cloud amount.
Effect of the Pauli principle in elastic scattering
Picklesimer, A.; Thaler, R. M.
1981-01-01
The effect of imposition of the Pauli principle for two-fragment elastic nuclear scattering is examined. It is shown that the antisymmetrized problem can be cast into the Lippmann-Schwinger form with an effective interaction in which the effect of the Pauli principle is entirely absorbed into the effective interaction potential operator. This result enables the formalism to be developed in analogy with the unsymmetrized formulation. Central to the approach is the choice of the off-shell extension of the transition operator. Comparison is made with a previously proposed treatment based on a different off-shell extension. It is shown that both the antisymmetrized transition operator and the associated optical potential proposed herein are readily expressed as spectator expansions in which the effect of the Pauli principle among the active fermions is incorporated in a physically appealing fashion at each stage of the expansion. NUCLEAR REACTIONS Antisymmetrization incorporated in elastic scattering and optical potential theory. Multiple scattering series and spectator expansion.
邱孝明; 黄林; 简广德
2002-01-01
A magnetohydrodynamic (MHD) formulation is derived to investigate and compare the mitigation effects of both the sheared axial flow and finite Larmor radius (FLR) on the Rayleigh-Taylor (RT) instability in Z-pinch implosions. The sheared axial flow is introduced into MHD equations in a conventional way and the FLR effect into the equations via а/аt → -i(ω + ik2⊥ρi2Ωi), as proposed in our previous paper [Chin. Phys. Lett. 2002, 19:217] , where k2⊥ρ2i is referred to FLR effect from the general kinetic theory of magnetized plasma. Therefore the linearized continuity and momentum equations for the perturbed massdensity and velocity include both the sheared axial flow and the FLR effect. It is found that the effect of sheared axial flow with a lower peak velocity can mitigate RT instability in the whole wavenumber region and the effect of sheared axial flow with a higher one can mitigate RT instability only in the large wavenumber region (for normalized wavenumber κ＞ 2.4); The effect of FLR can mitigate RT instability in the whole wavenumber region and the mitigation effect is stronger than that of the sheared axial flow with a lower peak velocity in the almost whole wavenumber region.
Relativistic effects in neutron-deuteron elastic scattering
Witala, H; Glöckle, W; Kamada, H
2004-01-01
We solved the three-nucleon Faddeev equation including relativistic features such as relativistic kinematics, boost effects and Wigner spin rotations. As dynamical input a relativistic nucleon-nucleon interaction exactly on-shell equivalent to the AV18 potential has been used. The effects of Wigner rotations for elastic scattering observables were found to be small. The boost effects are significant at higher energies.They diminish the transition matrix elements at higher energies and lead in spite of the increased relativistic phase-space factor as compared to the nonrelativistic one to rather small effects in the cross section, which are mostly restricted to the backward angles.
Effective Field Theory and Unitarity in Vector Boson Scattering
Sekulla, Marco; Ohl, Thorsten; Reuter, Jürgen
2016-01-01
Weak vector boson scattering at high energies will be one of the key measurements in current and upcoming LHC runs. It is most sensitive to any new physics associated with electroweak symmetry breaking. However, a conventional EFT analysis will fail at high energies. To address this problem, we present a parameter-free prescription valid for arbitrary perturbative and non-perturbative models: the T-matrix unitarization. We describe its implementation as an asymptotically consistent reference model matched to the low-energy effective theory. We show examples of typical observables of vector-boson scattering at the LHC in our unitarized framework. For many strongly-coupled models like composite Higgs models, dimension-8 operators might be actually the leading operators. In addition to those longitudinal and transversal dimension eight EFT operators, the effects of generic tensor and scalar resonances within simplified models are considered.
Effective field theory and unitarity in vector boson scattering
Sekulla, Marco [Karlsruher Institut fuer Technologie (KIT), Karlsruhe (Germany); Kilian, Wolfgang [Siegen Univ. (Germany); Ohl, Thorsten [Wuerzburg Univ. (Germany); Reuter, Juergen [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group
2016-10-15
Weak vector boson scattering at high energies will be one of the key measurements in current and upcoming LHC runs. It is most sensitive to any new physics associated with electroweak symmetry breaking. However, a conventional EFT analysis will fail at high energies. To address this problem, we present a parameter-free prescription valid for arbitrary perturbative and non-perturbative models: the T-matrix unitarization. We describe its implementation as an asymptotically consistent reference model matched to the low-energy effective theory. We show examples of typical observables of vector-boson scattering at the LHC in our unitarized framework. For many strongly-coupled models like composite Higgs models, dimension-8 operators might be actually the leading operators. In addition to those longitudinal and transversal dimension eight EFT operators, the effects of generic tensor and scalar resonances within simplified models are considered.
Transient Effects And Pump Depletion In Stimulated Raman Scattering
Carlsten, J. L.; Wenzel, R. G...; Druhl, K.
1983-11-01
Stimulated rotational Raman scattering in a 300-K multipass cell filled with para-H2 with a single-mode CO2-pumped laser is studied using a frequency-narrowed optical parametric oscillator (OPO) as a probe laser at the Stokes frequency for the So(0) transition. Amplification and pump depletion are examined as a function of incident pump energy. The pump depletion shows clear evidence of transient behavior. A theoretical treatment of transient stimulated Raman scattering, including effects of both pump depletion and medium saturation is presented. In a first approximation, diffraction effects are neglected, and only plane-wave interactions are considered. The theoretical results are compared to the experimental pulse shapes.
The effect of magnetic impurity scattering in Au films
无
2010-01-01
The magnetic impurity scattering plays an important role in the phase coherence behavior of thin films.By using the thickness and disorder dependences of the low temperature logarithmic anomaly in resistivity we are able to determine the concentration of magnetic impurities in Au films and demonstrate that the low temperature saturation or plateau in phase decoherence time is closely related with the Kondo effect.
Radar Array Signal Processing in the Presence of Scattering Effects
2008-01-15
Final INov . 2004 - Oct. 2007 4. TITLE AND SUBTITLE Sa. CON RACT NUMBER Radar Array Signal Processing in the Presence of Scattering Effects N/A 5b. GRANT...polarization. Hence, we considered models depicting how the features of this signal are affected by the medium materials through which the signal propagates. We...security (e.g., for nuclear materials ), and particle communications. We assume Poisson distribution for each detectors measurement within the
Effects of surface and interface scattering on anomalous Hall effect in Co/Pd multilayers
Guo, Z. B.
2012-09-27
In this paper, we report the results of surface and interface scattering on anomalous Hall effect in Co/Pd multilayers with perpendicular magnetic anisotropy. The surface scattering effect has been extracted from the total anomalous Hall effect. By scaling surface scattering contribution with ρAHs∼ργss, the exponent γ has been found to decrease with the increase of surface scattering resistivity, which could account for the thickness-dependent anomalous Hall effect. Interface diffusion induced by rapid thermal annealing modifies not only the magnetization and longitudinal resistivity but also the anomalous Hall effect; a large exponent γ ∼ 5.7 has been attributed to interface scattering-dominated anomalous Hall effect.
Photon Scattering in 3D Radiative MHD Simulations
Hayek, Wolfgang
2009-09-01
Recent results from 3D time-dependent radiative hydrodynamic simulations of stellar atmospheres are presented, which include the effects of coherent scattering in the radiative transfer treatment. Rayleigh scattering and electron scattering are accounted for in the source function, requiring an iterative solution of the transfer equation. Opacities and scattering coefficients are treated in the multigroup opacity approximation. The impact of scattering on the horizontal mean temperature structure is investigated, which is an important diagnostic for model atmospheres, with implications for line formation and stellar abundance measurements. We find that continuum scattering is not important for the atmosphere of a metal-poor Sun with metailicity [Fe/H] = -3.0, similar to the previously investigated photosphere at solar metallicity.
Sakata, Yoshitaro; Terasaki, Nao; Sakai, Kazufumi; Nonaka, Kazuhiro
2016-11-01
The stress-induced light scattering method (SILSM) was proposed for inspecting surface to detect polishing induced latent flaws. In this study, in order to clarify the mechanism of the light scattering intensity variation of latent flaws using SILSM, we have investigated stress effect of light scattering intensities using polarized light system and calculated the reflectance and the retardation using Jones matrix. As the results, we evaluated the change in the birefringence around a tip of a latent flaw between before and after stress were applied.
Relativistic (Dirac equation) effects in microscopic elastic scattering calculations
Hynes, M. V.; Picklesimer, A.; Tandy, P. C.; Thaler, R. M.
1985-04-01
A simple relativistic extension of the first-order multiple scattering mechanism for the optical potential is employed within the context of a Dirac equation description of elastic nucleon-nucleus scattering. A formulation of this problem in terms of a momentum-space integral equation displaying an identifiable nonrelativistic sector is described and applied. Extensive calculations are presented for proton scattering from 40Ca and 16O at energies between 100 and 500 MeV. Effects arising from the relativistic description of the propagation of the projectile are isolated and are shown to be responsible for most of the departures from typical nonrelativistic (Schrödinger) results. Off-shell and nonlocal effects are included and these, together with uncertainties in the nuclear densities, are shown not to compromise the characteristic improvement of forward angle spin observable predictions provided by the relativistic approach. The sensitivity to ambiguities in the Lorentz scalar and vector composition of the optical potential is displayed and discussed.
Relativistic (Dirac equation) effects in microscopic elastic scattering calculations
Hynes, M.V.; Picklesimer, A.; Tandy, P.C.; Thaler, R.M.
1985-04-01
A simple relativistic extension of the first-order multiple scattering mechanism for the optical potential is employed within the context of a Dirac equation description of elastic nucleon-nucleus scattering. A formulation of this problem in terms of a momentum-space integral equation displaying an identifiable nonrelativistic sector is described and applied. Extensive calculations are presented for proton scattering from /sup 40/Ca and /sup 16/O at energies between 100 and 500 MeV. Effects arising from the relativistic description of the propagation of the projectile are isolated and are shown to be responsible for most of the departures from typical nonrelativistic (Schroedinger) results. Off-shell and nonlocal effects are included and these, together with uncertainties in the nuclear densities, are shown not to compromise the characteristic improvement of forward angle spin observable predictions provided by the relativistic approach. The sensitivity to ambiguities in the Lorentz scalar and vector composition of the optical potential is displayed and discussed.
Nuclear effects in deep inelastic scattering and transition region
Kumano, S
2016-01-01
We discuss nuclear effects on neutrino-nuclear interactions in a wide kinematical range from shallow to deep inelastic scattering (DIS) region. There is necessity from neutrino communities to have precise neutrino-nucleus cross sections within several percent order for future measurements on neutrino oscillations and leptonic CP violation. We try to create a model to calculate neutrino cross sections in the wide kinematical range, from quasi-elastic scattering and resonance productions to the DIS. In this article, nuclear modifications of structure functions are mainly discussed, and a possible extension to the $Q^2 \\to 0$ region is explained. We also comment on the transition region between baryon resonances and the DIS. There are ongoing experimental efforts on nuclear modifications of structure functions or parton distribution functions such as by pA reactions at RHIC and LHC, Drell-Yan measurements at Fermilab, Miner$\
Refractive effects in the scattering of loosely bound nuclei
Cãrstoiu, F; Tribble, R E; Gagliardi, C A
2004-01-01
A study of the interaction of loosely bound nuclei 6,7Li at 9 and 19 AMeV with light targets has been undertaken. With the determination of unambiguous optical potentials in mind, elastic data for four projectile-target combinations and one neutron transfer reaction 13C(7Li,8Li)12C have been measured on a large angular range. The kinematical regime encompasses a region where the mean field (optical potential) has a marked variation with mass and energy, but turns out to be sufficiently surface transparent to allow strong refractive effects to be manifested in elastic scattering data at intermediate angles. The identified exotic feature, a "plateau" in the angular distributions at intermediate angles, is fully confirmed in four reaction channels and interpreted as a pre-rainbow oscillation resulting from the interference of the barrier and internal barrier farside scattering subamplitudes.
Continuum effects in the scattering of exotic nuclei
Druet, T. [Universite Libre de Bruxelles (ULB), Physique Quantique, C.P. 165/82, Brussels (Belgium); Universite Libre de Bruxelles (ULB), Physique Nucleaire Theorique et Physique Mathematique, Brussels (Belgium); Descouvemont, P. [Universite Libre de Bruxelles (ULB), Physique Nucleaire Theorique et Physique Mathematique, Brussels (Belgium)
2012-10-15
We discuss continuum effects in the scattering of exotic nuclei, and more specifically on the {sup 11}Be + {sup 64}Zn scattering. {sup 11}Be is a typical example of an exotic nucleus, with a low binding energy. Elastic, inelastic and breakup cross-sections of the {sup 11}Be + {sup 64}Zn system are computed in the Continuum Discretized Coupled Channel formalism, at energies near the Coulomb barrier. We show that converged cross-sections need high angular momenta as well as as large excitation energies in the wave functions of the projectile. Extensions to other systems are simulated by different collision energies, and by varying the binding energy of {sup 11}Be. (orig.)
Liu, Wanhai; Yu, Changping; Jiang, Hongbin; Li, Xinliang
2017-02-01
Based on the harmonic analysis [Liu et al., Phys. Plasmas 22, 112112 (2015)], the analytical investigation on the harmonic evolution in Rayleigh-Taylor instability (RTI) at a spherical interface has been extended to the general case of arbitrary Atwood numbers by using the method of the formal perturbation up to the third order in a small parameter. Our results show that the radius of the initial interface [i.e., Bell-Plessett (BP) effect] dramatically influences the harmonic evolution for arbitrary Atwood numbers. When the initial radius approaches infinity compared against the initial perturbation wavelength, the amplitudes of the first four harmonics will recover those in planar RTI. The BP effect makes the amplitudes of the zeroth, second, and third harmonics increase faster for a larger Atwood number than smaller one. The BP effect reduces the third-order negative feedback to the fundamental mode for a smaller Atwood number, and strengthens it for a larger one. Hence, the BP effect helps the fundamental mode grow faster for a smaller Atwood number.
Stability of Rayleigh-Taylor Vortices in Dusty Plasma
MA Jun; CHEN Yin-Hua; GAN Bao-Xia; WANG Fei-Hu; WANG Dong
2006-01-01
@@ The evolution of Rayleigh-Taylor mode in dusty plasma with vortex-flow is investigated. Based on fluid theory and Bayly's method, we derive the coupling equations describing the Rayleigh-Taylor mode in the core of vortex,and research the evolution characteristics of the perturbation amplitude with time numerically. It is shown that the eccentric of vortex and the content of dust have considerable effects on the amplitude evolutions.
An effective method for incoherent scattering radar's detecting ability evaluation
Lu, Ziqing; Yao, Ming; Deng, Xiaohua
2016-06-01
Ionospheric incoherent scatter radar (ISR), which is used to detect ionospheric electrons and ions, generally, has megawatt class transmission power and hundred meter level antenna aperture. The crucial purpose of this detecting technology is to get ionospheric parameters by acquiring the autocorrelation function and power spectrum of the target ionospheric plasma echoes. Whereas the ISR's echoes are very weak because of the small radar cross section of its target, estimating detecting ability will be significantly instructive and meaningful for ISR system design. In this paper, we evaluate the detecting ability through signal-to-noise ratio (SNR). The soft-target radar equation is deduced to be applicable to ISR, through which we use data from International Reference Ionosphere model to simulate signal-to-noise ratio (SNR) of echoes, and then comparing the measured SNR from European Incoherent Scatter Scientific Association and Advanced Modular Incoherent Scatter Radar with the simulation. The simulation results show good consistency with the measured SNR. For ISR, the topic of this paper is the first comparison between the calculated SNR and radar measurements; the detecting ability can be improved through increasing SNR. The effective method for ISR's detecting ability evaluation provides basis for design of radar system.
Beating Rayleigh's Curse by Imaging Using Phase Information
Tham, Weng-Kian; Ferretti, Hugo; Steinberg, Aephraim M.
2017-02-01
Every imaging system has a resolution limit, typically defined by Rayleigh's criterion. Given a fixed number of photons, the amount of information one can gain from an image about the separation between two sources falls to zero as the separation drops below this limit, an effect dubbed "Rayleigh's curse." Recently, in a quantum-information-inspired proposal, Tsang and co-workers found that there is, in principle, infinitely more information present in the full electromagnetic field in the image plane than in the intensity alone, and suggested methods for extracting this information and beating the Rayleigh limit. In this Letter, we experimentally demonstrate a simple scheme that captures most of this information, and show that it has a greatly improved ability to estimate the distance between a pair of closely separated sources, achieving near-quantum-limited performance and immunity to Rayleigh's curse.
Resolution effects and analysis of small-angle neutron scattering data
Pedersen, J.S.
1993-01-01
A discussion of the instrumental smearing effects for small-angle neutron scattering (SANS) data sets is given. It is shown that these effects can be described by a resolution function, which describes the distribution of scattering vectors probed for the nominal values of the scattering vector. ...
Effect of the Pauli principle in elastic scattering
Picklesimer, A.; Thaler, R.M.
1981-01-01
The effect of imposition of the Pauli principle for two-fragment elastic nuclear scattering is examined. It is shown that the antisymmetrized problem can be cast into the Lippmann-Schwinger form with an effective interaction in which the effect of the Pauli principle is entirely absorbed into the effective interaction potential operator. This result enables the formalism to be developed in analogy with the unsymmetrized formulation. Central to the approach is the choice of the off-shell extension of the transition operator. Comparison is made with a previously proposed treatment based on a different off-shell extension. It is shown that both the antisymmetrized transition operator and the associated optical potential proposed herein are readily expressed as spectator expansions in which the effect of the Pauli principle among the active fermions is incorporated in a physically appealing fashion at each stage of the expansion.
Terahertz scattering by granular composite materials: An effective medium theory
Kaushik, Mayank; Ng, Brian W.-H.; Fischer, Bernd M.; Abbott, Derek
2012-01-01
Terahertz (THz) spectroscopy and imaging have emerged as important tools for identification and classification of various substances, which exhibit absorption characteristics at distinct frequencies in the THz range. The spectral fingerprints can potentially be distorted or obscured by electromagnetic scattering caused by the granular nature of some substances. In this paper, we present THz time domain transmission measurements of granular polyethylene powders in order to investigate an effective medium theory that yields a parameterized model, which can be used to estimate the empirical measurements to good accuracy.
Quantum radiation reaction effects in multiphoton Compton scattering.
Di Piazza, A; Hatsagortsyan, K Z; Keitel, C H
2010-11-26
Radiation reaction effects in the interaction of an electron and a strong laser field are investigated in the realm of quantum electrodynamics. We identify the quantum radiation reaction with the multiple photon recoils experienced by the laser-driven electron due to consecutive incoherent photon emissions. After determining a quantum radiation dominated regime, we demonstrate how in this regime quantum signatures of the radiation reaction strongly affect multiphoton Compton scattering spectra and that they could be measurable in principle with presently available laser technology.
Nucleon-nucleon scattering from effective field theory
Kaplan, D B; Wise, M B; Kaplan, David B; Savage, Martin J; Wise, Mark B
1996-01-01
We perform a nonperturbative calculation of the 1S0 nucleon-nucleon scattering amplitude, using an effective field theory (EFT) expansion. We use dimensional regularization throughout, and the MS-bar renormalization scheme; our final result depends only on physical observables. We show that the EFT expansion of the real part of the inverse of the Feynman amplitude converges at momenta much greater than the scale that characterizes the derivative expansion of the EFT Lagrangian. Our conclusions are optimistic about the applicability of an EFT approach to the quantitative study of nuclear matter.
Momentum space approach to microscopic effects in elastic proton scattering
Picklesimer, A.; Tandy, P. C.; Thaler, R. M.; Wolfe, D. H.
1984-12-01
The microscopic nonrelativistic first-order optical potential for proton-nucleus scattering is studied in some detail. Momentum-space calculations have been performed for a number of different target nuclei at proton energies above ~100 MeV and these microscopic predictions are compared with experimental cross section, analyzing power, and spin-rotation function data. The input to these calculations consists of the free on-shell nucleon-nucleon t matrix, its nonlocal and off-shell structure, the treatment of the full-folding integral, and target densities obtained from electron scattering. Off-shell and nonlocal effects, as well as various factorization approximations, are studied. The sensitivity to uncertainties in the off-shell extension of the t matrix, within the context of the Love-Franey model, is explicity displayed. Similarly, uncertainties due to nonlocalities and incomplete knowledge of nuclear densities are shown. Explicit calculations using the t matrix of Love and Franey indicate that these effects play significant roles only for relatively large angles (θ<~60°) and/or lower energies (~150 MeV). These studies reinforce the conclusion that the lack of agreement between such first-order predictions and the data for spin observables at small angles arises from a physical effect not included in the nonrelativistic first-order theory, rather than from any uncertainty in the calculation or in its input.
Stone, Kevin H.
2014-07-14
Some polymer properties, such as conductivity, are very sensitive to short- and intermediate-range orientational and positional ordering of anisotropic molecular functional groups, and yet means to characterize orientational order in disordered systems are very limited. We demonstrate that resonant scattering at the carbon K-edge is uniquely sensitive to short-range orientation correlations in polymers through depolarized scattering at high momentum transfers, using atactic polystyrene as a well-characterized test system. Depolarized scattering is found to coexist with unpolarized fluorescence, and to exhibit pronounced anisotropy. We also quantify the spatially averaged optical anisotropy from low-angle reflectivity measurements, finding anisotropy consistent with prior visible, x-ray absorption, and theoretical studies. The average anisotropy is much smaller than that in the depolarized scattering and the two have different character. Both measurements exhibit clear spectral signatures from the phenyl rings and the polyethylene-like backbone. Discussion focuses on analysis considerations and prospects for using this depolarized scattering for studies of disorder in soft condensed matter.
Stone, Kevin H.; Kortright, Jeffrey B.
2014-09-01
Some polymer properties, such as conductivity, are very sensitive to short- and intermediate-range orientational and positional ordering of anisotropic molecular functional groups, and yet means to characterize orientational order in disordered systems are very limited. We demonstrate that resonant scattering at the carbon K edge is uniquely sensitive to short-range orientation correlations in polymers through depolarized scattering at high momentum transfers, using atactic polystyrene as a well-characterized test system. Depolarized scattering is found to coexist with unpolarized fluorescence and to exhibit pronounced anisotropy. We also quantify the spatially averaged optical anisotropy from low-angle reflectivity measurements, finding anisotropy consistent with prior visible, x-ray absorption, and theoretical studies. The average anisotropy is much smaller than that in the depolarized scattering and the two have different character. Both measurements exhibit clear spectral signatures from the phenyl rings and the polyethylenelike backbone. Discussion focuses on analysis considerations and prospects for using this depolarized scattering for studies of disorder in soft condensed matter.
Effect of anisotropic scattering on radiative heat transfer in two-dimensional rectangular media
Hao Jin Bo
2003-01-01
Effect of scattering on radiative heat transfer in two-dimensional rectangular media by the finite-volume method has been studied. Compared with the existing solutions, it shows that the result obtained by the finite-volume method is reliable. Furthermore, relative errors caused by the approximation that linear and nonlinear anisotropic scattering media is simplified to isotropic scattering media have been studied.
Millimeter Wave Scattering from Neutral and Charged Water Droplets
Heifetz, Alexander; Liao, Shaolin; Gopalsami, N Sami; Raptis, A C Paul
2010-01-01
We investigated 94GHz millimeter wave (MMW) scattering from neutral and charged water mist produced in the laboratory with an ultrasonic atomizer. Diffusion charging of the mist was accomplished with a negative ion generator (NIG). We observed increased forward and backscattering of MMW from charged mist, as compared to MMW scattering from an uncharged mist. In order to interpret the experimental results, we developed a model based on classical electrodynamics theory of scattering from a dielectric sphere with diffusion-deposited mobile surface charge. In this approach, scattering and extinction cross-sections are calculated for a charged Rayleigh particle with effective dielectric constant consisting of the volume dielectric function of the neutral sphere and surface dielectric function due to the oscillation of the surface charge in the presence of applied electric field. For small droplets with (radius smaller than 100nm), this model predicts increased MMW scattering from charged mist, which is qualitative...
Effect of dust particle polarization on scattering processes in complex plasmas
Kodanova, S. K.; Ramazanov, T. S.; Bastykova, N. Kh.; Moldabekov, Zh. A. [Institute for Experimental and Theoretical Physics, Al-Farabi Kazakh National University, 71 Al-Farabi Str., 050040 Almaty (Kazakhstan)
2015-06-15
Screened interaction potentials in dusty plasmas taking into account the polarization of dust particles have been obtained. On the basis of screened potentials scattering processes for ion-dust particle and dust particle-dust particle pairs have been studied. In particular, the scattering cross section is considered. The scattering processes for which the dust grain polarization is unimportant have been found. The effect of zero angle dust particle-dust particle scattering is predicted.
Bouteraa, Mondher; Nouar, Chérif
2015-12-01
Finite-amplitude thermal convection in a shear-thinning fluid layer between two horizontal plates of finite thermal conductivity is considered. Weakly nonlinear analysis is adopted as a first approach to investigate nonlinear effects. The rheological behavior of the fluid is described by the Carreau model. As a first step, the critical conditions for the onset of convection are computed as a function of the ratio ξ of the thermal conductivity of the plates to the thermal conductivity of the fluid. In agreement with the literature, the critical Rayleigh number Ra(c) and the critical wave number k(c) decrease from 1708 to 720 and from 3.11 to 0, when ξ decreases from infinity to zero. In the second step, the critical value α(c) of the shear-thinning degree above which the bifurcation becomes subcritical is determined. It is shown that α(c) increases with decreasing ξ. The stability of rolls and squares is then investigated as a function of ξ and the rheological parameters. The limit value ξ(c), below which squares are stable, decreases with increasing shear-thinning effects. This is related to the fact that shear-thinning effects increase the nonlinear interactions between sets of rolls that constitute the square patterns [M. Bouteraa et al., J. Fluid Mech. 767, 696 (2015)]. For a significant deviation from the critical conditions, nonlinear convection terms and nonlinear viscous terms become stronger, leading to a further diminution of ξ(c). The dependency of the heat transfer on ξ and the rheological parameters is reported. It is consistent with the maximum heat transfer principle. Finally, the flow structure and the viscosity field are represented for weakly and highly conducting plates.
Long-range effects in electron scattering by polar molecules
Fabrikant, Ilya I.
2016-11-01
We review long-range effects in electron collisions with polar molecules, starting with elastic scattering. We then go to rotationally and vibrationally inelastic processes and dissociative electron attachment. The last two are strongly affected by vibrational Feshbach resonances which have been observed and described theoretically in many systems from simple diatomic molecules to more complex polyatomics, biologically relevant molecules, and van der Waals clusters. We then review environmental effects which include electron interaction with molecules adsorbed on surfaces and molecules in cluster environments. We concentrate on physics rather than on listing results of ab initio calculations. With increasing complexity of targets and processes model approaches become more relevant. We demonstrate their success in the theoretical description of electron attachment to polyatomic molecules and to molecules in complex environments.
Effective Field Theories from Soft Limits of Scattering Amplitudes.
Cheung, Clifford; Kampf, Karol; Novotny, Jiri; Trnka, Jaroslav
2015-06-05
We derive scalar effective field theories-Lagrangians, symmetries, and all-from on-shell scattering amplitudes constructed purely from Lorentz invariance, factorization, a fixed power counting order in derivatives, and a fixed order at which amplitudes vanish in the soft limit. These constraints leave free parameters in the amplitude which are the coupling constants of well-known theories: Nambu-Goldstone bosons, Dirac-Born-Infeld scalars, and Galilean internal shift symmetries. Moreover, soft limits imply conditions on the Noether current which can then be inverted to derive Lagrangians for each theory. We propose a natural classification of all scalar effective field theories according to two numbers which encode the derivative power counting and soft behavior of the corresponding amplitudes. In those cases where there is no consistent amplitude, the corresponding theory does not exist.
Higher twist effects in deeply virtual Compton scattering
Pirnay, Bjoern Michael
2016-08-01
In this work we explore the effects of higher twist power corrections on the deeply virtual Compton scattering process. The calculation of the helicity amplitudes for all possible polarization combinations is performed within the framework of QCD operator product expansion. As a result the known accuracy of the amplitudes is improved to include the (kinematic) twist-4 contributions. For the most part the analysis focuses on spin-1/2 targets, the answers for scalar targets conveniently emerge as a byproduct. We investigate the analytical structure of these corrections and prove consistency with QCD factorization. We give an estimation of the numerical impact of the sub-leading twist contributions for proton targets with the help of a phenomenological model for the nonperturbative proton generalized parton distributions. We compare different twist approximations and relate predictions for physical observables to experiments performed by the Hall A, CLAS, HERMES, H1 and ZEUS collaborations. The estimate also includes a numerical study for planned COMPASS-II runs. Throughout the analysis special emphasis is put on the convention dependence induced by finite twist truncation of scattering amplitudes.
Electron scattering from neon via effective range theory
Fedus, Kamil, E-mail: kamil@fizyka.umk.pl [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Torun (Poland)
2014-07-01
Elastic cross-sections for electron scattering on neon from 0 energy up to 16 eV are analyzed by an analytical approach to the modified effective range theory (MERT). It is shown that energy and angular variations of elastic differential, integral and momentum transfer cross sections can be accurately parameterized by six MERT coefficients up to the energy threshold for the first Feshbach resonance. MERT parameters are determined empirically by numerical comparison with large collection of available experimental data of elastic total (integral) cross-sections. The present analysis is validated against numerous electron beams and swarm experiments. The comparison of derived MERT parameters with those found for other noble gases, helium, argon and krypton, is done. The derived scattering length (for the s-partial wave) in neon, 0.227a0, agrees well with recent theories; it is small but, differently from Ar and Kr, still positive. Analogue parameters for the p-wave and the d-wave are negative and positive respectively for all the four gases compared. (author)
Refractive effects in the scattering of loosely bound nuclei
Carstoiu, F.; Trache, L.; Tribble, R.E.; Gagliardi, C.A. [Texas A and M Univ., College Station, TX (United States). Cyclotron Inst; Carstoiu, F. [Laboratoire de Physique Corpusculaire, IN2P3-CNRS, ISMRA, Universite de Caen, 14 - Caen (France); Carstoiu, F. [National Institute for Physics and Nuclear Engineering, Horia Hulubei, Bucharest-Magurele (Romania)
2004-07-01
A study of the interaction of the loosely bound nuclei {sup 6,7}Li at 9 and 19 MeV/nucleon with light targets has been undertaken. With the determination of unambiguous optical potentials in mind, elastic data for four projectile-target combinations and one neutron transfer reaction {sup 13}C({sup 7}Li,{sup 8}Li){sup 12}C have been measured over a large angular range. The kinematical regime encompasses a region where the mean field (optical potential) has a marked variation with mass and energy, but turns out to be sufficiently surface transparent to allow strong refractive effects to be manifested in elastic scattering data at intermediate angles. The identified exotic feature, a 'plateau' in the angular distributions at intermediate angles, is fully confirmed in four reaction channels and is interpreted as a pre-rainbow oscillation resulting from the interference of the barrier and internal barrier far-side scattering sub-amplitudes. (authors)
Non-perturbative QCD effects in forward scattering at LHC
Bahia, C A S; Luna, E G S
2015-01-01
We study infrared contributions to semihard parton-parton interactions by considering an effective charge whose finite infrared behavior is constrained by a dynamical mass scale. Using an eikonal QCD-based model in order to connect this semihard parton-level dynamics to the hadron-hadron scattering, we obtain predictions for the proton-proton ($pp$) and antiproton-proton ($\\bar{p}p$) total cross sections, $\\sigma_{tot}^{pp,\\bar{p}p}$, and the ratios of the real to imaginary part of the forward scattering amplitude, $\\rho^{pp,\\bar{p}p}$. We discuss the theoretical aspects of this formalism and consider the phenomenological implications of a class of energy-dependent form factors in the high-energy behavior of the forward amplitude. We introduce integral dispersion relations specially tailored to relate the real and imaginary parts of eikonals with energy-dependent form factors. Our results, obtained using a group of updated sets of parton distribution functions (PDFs), are consistent with the recent data from ...
Experimental study on stimulated scattering of ZnO nanospheres dispersed in water
Shi, Jiulin, E-mail: hyq1304@126.com; Wu, Haopeng [Nanchang Hangkong University, Jiangxi Engineering Laboratory for Optoelectronics Testing Technology (China); Yan, Feng; Yang, Junjie [Nanchang Hangkong University, School of Measuring and Optical Engineering (China); He, Xingdao, E-mail: xingdaohe@126.com [Nanchang Hangkong University, Jiangxi Engineering Laboratory for Optoelectronics Testing Technology (China)
2016-01-15
The backward stimulated scattering (BSS) from ZnO nanospheres dispersed in water has been investigated experimentally by employing a Nd:YAG pulse laser with ∼532 nm wavelength and ∼8 ns pulse width as the pump laser source. The present results show that the BSS effect is uniquely and unequivocally different compared to other known stimulated scattering, such as stimulated Rayleigh scattering, stimulated Brillouin scattering, and stimulated Raman scattering, and it displays the characteristics of no frequency shift and threshold dependence on initial spontaneous Mie scattering seed source. These can be understood by means of the Mie scattering theory and a laser-induced stationary Bragg grating model.
Cannavacciuolo, L.; Sommer, C.; Pedersen, J.S.;
2000-01-01
We present a systematic Monte Carlo study of the scattering function S(q) of semiflexible polyelectrolytes at infinite dilution, in solutions with different concentrations of added salt. In the spirit of a theoretical description of polyelectrolytes in terms of the equivalent parameters, namely...... outlined in the Odijk-Skolnick-Fixman theory, in which the behavior of charged polymers is described only in terms of increasing local rigidity and excluded volume effects. Moreover, the Monte Carlo data are found to be in very good agreement with experimental scattering measurements with equilibrium...
Momentum space approach to microscopic effects in elastic proton scattering
Picklesimer, A.; Tandy, P.C.; Thaler, R.M.; Wolfe, D.H.
1984-06-01
The microscopic non-relativistic first-order optical potential for proton-nucleus scattering is studied in some detail. Momentum-space calculations have been performed for a number of different target nucli at proton energies above approx.100 MeV and these microscopic predictions are compared with experimental cross section, analyzing power, and spin-rotation function data. The input to these calculations consists of the free on-shell nucleon-nucleon t-matrix, its non-local and off-shell structure, the treatment of the full-folding integral, and target densities obtained from electron scattering. Off-shell and non-local effects, as well as various factorization approximations, are studied. The sensitivity to uncertainies in the off-shell extension of the t-matrix, within the context of the Love-Franey model, is explicitly displayed. Similarly, uncertainties due to non-localities and incomplete knowledge of nuclear densities are shown. Explicit calculations using the t-matrix of Love and Franey indicate that these effects play significant roles only for relatively large angles (THETA less than or equal to 60/sup 0/) and/or lower energies (approx.150 MeV). These studies reinforce the conclusion that the lack of agreement between such first-order predictions and the data for spin observable at small angles arises from a physical effect not included in the non-relativistic first-order theory, rather than from any uncertainty in the calculation or in its input. 31 references.
Kuranz, Carolyn C.; Drake, R. Paul; Park, Hye Sook; Huntington, Channing; Miles, Aaron R.; Remington, Bruce A.; Plewa, Tomek; Trantham, Matt; Shvarts, Dov; Raman, Kumar; MacLaren, Steven; Wan, Wesley; Doss, Forrest; Kline, John; Flippos, Kirk; Malamud, Guy; Handy, Timothy; Prisbey, Shon; Grosskopf, Michael; Krauland, Christine; Klein, Sallee; Harding, Eric; Wallace, Russell; Marion, Donna; Kalantar, Dan
2017-06-01
Energy-transport effects can alter the structure that develops as a supernova evolves into a supernova remnant. The Rayleigh Taylor (RT) instability is thought to produce structure at the interface between the stellar ejecta and the circumstellar matter (CSM), based on simple models and hydrodynamic simulations. When a blast wave emerges from an exploding star, it drives a forward shock into the CSM and a reverse shock forms in the expanding stellar ejecta, creating a young supernova remnant (SNR). As mass accumulates in the shocked layers, the interface between these two shocks decelerates, becoming unstable to the RT instability. Simulations predict that RT produces structures at this interface, having a range of spatial scales. When the CSM is dense enough, as in the case of SN 1993J, the hot shocked matter can produce significant radiative fluxes that affect the emission from the SNR. Here we report experimental results from the National Ignition Facility (NIF) to explore how large energy fluxes, which are present in supernovae such as SN 1993J, might affect this structure. The experiment used NIF to create a RT unstable interface subject to a high energy flux by the emergence of a blast wave into lower-density matter, in analogy to the SNR. We also preformed and with a low energy flux to compare the affect of the energy flux on the instability growth. We found that the RT growth was reduced in the experiments with a high energy flux. In analyzing the comparison with SN 1993J, we discovered that the energy fluxes produced by heat conduction appear to be larger than the radiative energy fluxes, and large enough to have dramatic consequences. No reported astrophysical simulations have included radiation and heat conduction self-consistently in modeling SNRs.
Dark matter effective field theory scattering in direct detection experiments
Schneck, K.; Cabrera, B.; Cerdeno, D. G.; Mandic, V.; Rogers, H. E.; Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.; Barker, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.; Borgland, A.; Brandt, D.; Brink, P. L.; Bunker, R.; Caldwell, D. O.; Calkins, R.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, Priscilla B.; Daal, M.; Di Stefano, P. C.; Doughty, T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.; Hall, Jeter C.; Harris, H. R.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jardin, D. M.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Leder, A.; Loer, B.; Lopez Asamar, E.; Lukens, W.; Mahapatra, R.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt, R. A.; Morales Mendoza, J. D.; Oser, S. M.; Page, K.; Page, W. A.; Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Roberts, A.; Saab, T.; Sadoulet, B.; Sander, J.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.; Speller, D.; Toback, D.; Upadhyayula, S.; Villano, A. N.; Welliver, B.; Wilson, J. S.; Wright, D. H.; Yang, X.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.
2015-05-01
We examine the consequences of the effective eld theory (EFT) of dark matter-nucleon scattering or current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. We demonstrate that spectral di*erences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. We also discuss the implications of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.
Dark matter effective field theory scattering in direct detection experiments
Schneck, K.; Cabrera, B.; Cerdeño, D. G.; Mandic, V.; Rogers, H. E.; Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.; Barker, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.; Borgland, A.; Brandt, D.; Brink, P. L.; Bunker, R.; Caldwell, D. O.; Calkins, R.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.; Hall, J.; Harris, H. R.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jardin, D. M.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Leder, A.; Loer, B.; Lopez Asamar, E.; Lukens, P.; Mahapatra, R.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt, R. A.; Morales Mendoza, J. D.; Oser, S. M.; Page, K.; Page, W. A.; Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Roberts, A.; Saab, T.; Sadoulet, B.; Sander, J.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.; Speller, D.; Toback, D.; Upadhyayula, S.; Villano, A. N.; Welliver, B.; Wilson, J. S.; Wright, D. H.; Yang, X.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.
2015-05-18
We examine the consequences of the effective field theory (EFT) of dark matter-nucleon scattering for current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. Here. we demonstrate that spectral differences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. In conclusion, we discuss the implications of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.
Dark matter effective field theory scattering in direct detection experiments
Schneck, K; Cerdeno, D G; Mandic, V; Rogers, H E; Agnese, R; Anderson, A J; Asai, M; Balakishiyeva, D; Barker, D; Thakur, R Basu; Bauer, D A; Billard, J; Borgland, A; Brandt, D; Brink, P L; Bunker, R; Caldwell, D O; Calkins, R; Chagani, H; Chen, Y; Cooley, J; Cornell, B; Crewdson, C H; Cushman, P; Daal, M; Di Stefano, P C F; Doughty, T; Esteban, L; Fallows, S; Figueroa-Feliciano, E; Godfrey, G L; Golwala, S R; Hall, J; Harris, H R; Hofer, T; Holmgren, D; Hsu, L; Huber, M E; Jardin, D M; Jastram, A; Kamaev, O; Kara, B; Kelsey, M H; Kennedy, A; Leder, A; Loer, B; Asamar, E Lopez; Lukens, P; Mahapatra, R; McCarthy, K A; Mirabolfathi, N; Moffatt, R A; Mendoza, J D Morales; Oser, S M; Page, K; Page, W A; Partridge, R; Pepin, M; Phipps, A; Prasad, K; Pyle, M; Qiu, H; Rau, W; Redl, P; Reisetter, A; Ricci, Y; Roberts, A; Saab, T; Sadoulet, B; Sander, J; Schnee, R W; Scorza, S; Serfass, B; Shank, B; Speller, D; Toback, D; Upadhyayula, S; Villano, A N; Welliver, B; Wilson, J S; Wright, D H; Yang, X; Yellin, S; Yen, J J; Young, B A; Zhang, J
2015-01-01
We examine the consequences of the effective field theory (EFT) of dark matter-nucleon scattering for current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. We demonstrate that spectral differences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. We also discuss the implications of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.
Dark matter effective field theory scattering in direct detection experiments
Schneck, K.; Cabrera, B.; Cerdeño, D. G.; Mandic, V.; Rogers, H. E.; Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.; Barker, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.; Borgland, A.; Brandt, D.; Brink, P. L.; Bunker, R.; Caldwell, D. O.; Calkins, R.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.; Hall, J.; Harris, H. R.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jardin, D. M.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Leder, A.; Loer, B.; Lopez Asamar, E.; Lukens, P.; Mahapatra, R.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt, R. A.; Morales Mendoza, J. D.; Oser, S. M.; Page, K.; Page, W. A.; Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Roberts, A.; Saab, T.; Sadoulet, B.; Sander, J.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.; Speller, D.; Toback, D.; Upadhyayula, S.; Villano, A. N.; Welliver, B.; Wilson, J. S.; Wright, D. H.; Yang, X.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.
2015-05-18
We examine the consequences of the effective field theory (EFT) of dark matter–nucleon scattering for current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. We demonstrate that spectral differences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. We also discuss the implications of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.
Coexisting Raman- and Rayleigh-Enhanced Four-Wave Mixing in Femtosecond Polarization Beats
NIE Zhi-Qiang; ZHAO Yan; ZHANG Yan-Peng; GAN Chen-Li; ZHENG Huai-Sin; LI Chang-Biao; LU Ke-Qing
2009-01-01
Based on the polarization interference of Raman- and Rayleigh-enhanced four-wave mixing processes,heterodyne detection of the Raman,Rayleigh and coexisting Raman and Rayleigh femtosecond difference-frequency polarization beats is investigated in the cw and the three Markovian stochastic models,respectively.These two processes exhibit asymmetric and symmetric spectra,respectively,and the thermal effect in them can be suppressed by a field-correlation method.Such studies of coexisting Raman- and Rayleigh-enhanced four-wave mixing processes can have important applications in coherence quantum control,and quantum information processing.
HUANG Lin; JIAN Guang-de; QIU Xiao-ming
2007-01-01
The synergistic stabilizing effect of gyroviscosity and sheared axial flow on the Rayleigh-Taylor instability in Z-pinch implosions is studied by means of the incompressible viscid magneto-hydrodynamic equations. The gyroviscosity (or finite Larmor radius) effects are introduced in the momentum equation through an anisotropic ion stress tensor. Dispersion relation with the effect of a density discontinuity is derived. The results indicate that the short-wavelength modes of the Rayleigh-Taylor instability are easily stabilized by the gyroviscosity effects. The long wavelength modes are stabilized by the sufficient sheared axial flow. However, the synergistic effects of the finite Larmor radius and sheared axial flow can heavily mitigate the Rayleigh-Taylor instability. This synergistic effect can compress the Rayleigh-Taylor instability to a narrow wave number region. Even with a sufficient gyroviscosity and large enough flow velocity, the synergistic effect can completely suppressed the Rayleigh-Taylor instability in whole wave number region.
A study of scattered radiation effect on digital radiography imaging system
Baek, Cheol Ha [Dept. of Radiological Science, Dongseo University, Busan (Korea, Republic of)
2017-03-15
Scattered radiation is inherent phenomenon of x-ray, which occurs to the subject (or patient). Therefore it cannot be avoidable but also interacts as serious noise factor because the only meaningful information on x-ray radiography is primary x-ray photons. The purpose of this study was to quantify scattered radiation for various shooting parameters and to verify the effect of anti-scatter grid. We employed beam stopper method to characterize scatter to primary ratio. To evaluate effect on the projection images calculated contrast to noise ratio of given shooting parameters. From the experiments, we identified the scattered radiation increases in thicker patient and smaller air gap. Moreover, scattered radiation degraded contrast to noise ratio of the projection images. We find out that the anti-scatter grid rejected scattered radiation effectively, however there were not fewer than 100% of scatter to primary ratio in some shooting parameters. The results demonstrate that the scattered radiation was serious problem of medical x-ray system, we confirmed that the scattered radiation was not considerable factor of digital radiography.
The effect of multiple scattering on the aspect sensitivity and polarization of radio auroral echoes
Donovan, E.F.; Moorcroft, D.R. (Western Ontario, University, London (Canada))
1992-04-01
A Monte Carlo model of radio wave scattering in the auroral electrojet has been developed to investigate multiple scattering of radio auroral echoes. Using this model, predictions of the aspect angle behavior of first-, second-, and third-order scattered power have been made. The results indicate that multiple scattering may be an important effect for VHF radars which observe the auroral E region at large magnetic aspect angles. The model shows that linearly polarized radio waves can become depolarized because of multiple scattering if the radio transmitter is horizontally polarized but not if the radio transmitter is vertically polarized. 52 refs.
Imaging Rayleigh wave attenuation with USArray
Bao, Xueyang; Dalton, Colleen A.; Jin, Ge; Gaherty, James B.; Shen, Yang
2016-07-01
The EarthScope USArray provides an opportunity to obtain detailed images of the continental upper mantle at an unprecedented scale. The majority of mantle models derived from USArray data to date contain spatial variations in seismic-wave speed; however, in many cases these data sets do not by themselves allow a non-unique interpretation. Joint interpretation of seismic attenuation and velocity models can improve upon the interpretations based only on velocity and provide important constraints on the temperature, composition, melt content, and volatile content of the mantle. The surface wave amplitudes that constrain upper-mantle attenuation are sensitive to factors in addition to attenuation, including the earthquake source excitation, focusing and defocusing by elastic structure, and local site amplification. Because of the difficulty of isolating attenuation from these other factors, little is known about the attenuation structure of the North American upper mantle. In this study, Rayleigh wave traveltime and amplitude in the period range 25-100 s are measured using an interstation cross-correlation technique, which takes advantage of waveform similarity at nearby stations. Several estimates of Rayleigh wave attenuation and site amplification are generated at each period, using different approaches to separate the effects of attenuation and local site amplification on amplitude. It is assumed that focusing and defocusing effects can be described by the Laplacian of the traveltime field. All approaches identify the same large-scale patterns in attenuation, including areas where the attenuation values are likely contaminated by unmodelled focusing and defocusing effects. Regionally averaged attenuation maps are constructed after removal of the contaminated attenuation values, and the variations in intrinsic shear attenuation that are suggested by these Rayleigh wave attenuation maps are explored.
Formal analogy between Compton scattering and Doppler effect
Nielsen, A.; Olsen, Jørgen Seir
1966-01-01
Viewed from the scatterer, the energy of the incoming photon or particle is equal to that of the outgoing, and the angle of incidence is equal to the angle of reflection, when the direction of the velocity of the scatterer after the collision is taken as reference. This paper sets out to prove th...
Leaky Rayleigh wave investigation on mortar samples.
Neuenschwander, J; Schmidt, Th; Lüthi, Th; Romer, M
2006-12-01
Aggressive mineralized ground water may harm the concrete cover of tunnels and other underground constructions. Within a current research project mortar samples are used to study the effects of sulfate interaction in accelerated laboratory experiments. A nondestructive test method based on ultrasonic surface waves was developed to investigate the topmost layer of mortar samples. A pitch and catch arrangement is introduced for the generation and reception of leaky Rayleigh waves in an immersion technique allowing the measurement of their propagation velocity. The technique has been successfully verified for the reference materials aluminium, copper, and stainless steel. First measurements performed on mortar specimens demonstrate the applicability of this new diagnostic tool.
Transverse spin effects in polarized semi inclusive deep inelastic scattering
Pappalardo, Luciano Libero
2008-10-15
The theoretical framework for the inclusive and semi-inclusive deep inelastic scattering is provided in Chapters 2 and 3, respectively. While a phenomenological and historical perspective is adopted in Chapter 2 for the description of the inclusive processes, a detailed treatment of the formalism concerning the physics of the transverse degrees of freedom of the nucleon is presented in Chapter 3. In Chapter 4 the main components of the HERMES experimental apparatus are presented. The extraction of the Collins and Sivers moments is discussed in Chapter 5 after a brief overview of the main steps of the data analysis. A selection of systematic studies is also reported at the end of the chapter. Chapter 6 is completely devoted to the estimate of the acceptance and smearing effects on the extracted azimuthal moments. A crucial role in the studies presented is played by a newly developed Monte Carlo generator which simulates azimuthal asymmetries arising from intrinsic quark momenta. A novel approach for the estimate of the acceptance effects is presented at the end of the chapter. The extracted Collins and Sivers moments, corrected for the acceptance effects, are shown in Chapter 7. The discussion and the interpretation of the results, together with a preliminary extraction of the Sivers polarization, are also treated in Chapter 7. Final conclusions and a brief summary are reported in Chapter 8. (orig.)
Focussing effects in laser-electron Thomson scattering
Harvey, C; Holkundkar, A R
2016-01-01
We study the effects of laser pulse focussing on the spectral properties of Thomson scattered radiation. Modelling the laser as a paraxial beam we find that, in all but the most extreme cases of focussing, the temporal envelope has a much bigger effect on the spectrum than the focussing itself. For the case of ultra-short pulses where the paraxial model is no longer valid, we adopt a sub-cycle vector beam description of the field. It is found that the emission harmonics are blue shifted and broaden out in frequency space as the pulse becomes shorter. Additionally the carrier envelope phase becomes important, resulting in an angular asymmetry in the spectrum. We then use the same model to study the effects of focussing beyond the limit where the paraxial expansion is valid. It is found that fields focussed to sub-wavelength spot sizes produce spectra that are qualitatively similar to those from sub-cycle pulses due to the shortening of the pulse with focussing. Finally, we study high-intensity fields and find ...
One-particle reducibility in effective scattering theory
Vereshagin, V.
2016-10-01
To construct the reasonable renormalization scheme suitable for the effective theories one needs to resolve the "problem of couplings" because the number of free parameters in a theory should be finite. Otherwise the theory would loose its predictive power. In the case of effective theory already the first step on this way shows the necessity to solve the above-mentioned problem for the 1-loop 2-leg function traditionally called self energy. In contrast to the customary renormalizable models the corresponding Feynman graph demonstrates divergencies that require introducing of an infinite number of prescriptions. In the recent paper [1] it has been shown that the way out of this difficulty requires the revision of the notion of one-particle reducibility. The point is that in effective scattering theory one can introduce two different notions: the graphic reducibility and the analytic one. Below we explain the main ideas of the paper [1] and recall some notions and definitions introduced earlier in [2] and [3].
Inverse Scattering Method and Soliton Solution Family for String Effective Action
GAO Ya-Jun
2009-01-01
A modified Hauser-Ernst-type linear system is established and used to develop an inverse scattering method for solving the motion equations of the string effective action describing the coupled gravity, dilaton and Kalb-Ramond fields. The reduction procedures in this inverse scattering method are found to be fairly simple, which makes the proposed inverse scattering method applied fine and effective. As an application, a concrete family of soliton solutions for the considered theory is obtained.
Study on the shadowing effect for optical wave scattering from randomly rough surface
Lixin Guo(郭立新); Yunhua Wang(王运华); Zhensen Wu(吴振森)
2004-01-01
Based on the Kirchhoff approximation for rough surface scattering and by calculating the shadowing function of the rough surface, the formula of the scattering cross section of the dielectric rough surface is presented with consideration of the shadowing effect for the optical wave incidence. It is obtained that in comparison with the conventional Kirchhoff solution, the shadowing effect should not be neglected for the optical wave scattering from the rough surface. The influence of the shadowing effect for different incidence angle, surface root mean square slope, and surface roughness on the scattering cross section is discussed in detail.
Sivers Effect in Dihadron Semi-Inclusive Deep Inelastic Scattering
Kotzinian, Aram; Thomas, Anthony W
2014-01-01
The Sivers effect describes the correlation of the unpolarized parton's transverse momentum with the transverse spin of the nucleon. It manifests as a sine modulation of the cross section for single hadron semi-inclusive deep inelastic scattering (SIDIS) on a transversely polarized nucleon with the azimuthal angle between the produced hadron's transverse momentum and the nucleon spin ($\\varphi_h$ and $\\varphi_S$, respectively). It has been recently suggested that the Sivers effect can also be measured in two hadron SIDIS process as sine modulations involving the azimuthal angles $\\varphi_T$ and $\\varphi_R$ of both the total and the relative transverse momenta of the hadron pair. Here we present the detailed derivation of the two hadron SIDIS cross section using simple parton-model inspired functional forms for both the parton distribution and the fragmentation functions. We show explicitly that the terms corresponding to the $\\sin(\\varphi_R-\\varphi_S)$ and $\\sin(\\varphi_T-\\varphi_S)$ modulations are non-zero....
1982-03-31
68 Figure 26. Least Squares Analysis of Scattering Data Presented in Figure 24. +, Prism separation of I mm; o, Prism separa- tion of 52 mm...rived by Marcuse , and we will later show its appropriateness using a some- what different analysis. For Rayleigh scattering, the form of the...scattering centers of uniform size. (3)Following a more general statistical analysis by Marcuse , the formula - 41 N(koa2Sn)(z) L(ka), scat 0 (37) L(kaO
Light scattering by fractal dust aggregates: I. Angular dependence of scattering
Tazaki, Ryo; Okuzumi, Satoshi; Kataoka, Akimasa; Nomura, Hideko
2016-01-01
In protoplanetary disks, micron-sized dust grains coagulate to form highly porous dust aggregates. Because the optical properties of these aggregates are not completely understood, it is important to investigate how porous dust aggregates scatter light. In this study, the light scattering properties of porous dust aggregates were calculated using a rigorous method, the T-matrix method, and the results were then compared with those obtained using the Rayleigh-Gans-Debye (RGD) theory and Mie theory with the effective medium approximation (EMT). The RGD theory is applicable to moderately large aggregates made of nearly transparent monomers. This study considered two types of porous dust aggregates, ballistic cluster-cluster agglomerates (BCCAs) and ballistic particle-cluster agglomerates (BPCAs). First, the angular dependence of the scattered intensity was shown to reflect the hierarchical structure of dust aggregates; the large-scale structure of the aggregates is responsible for the intensity at small scatteri...
Parnell, William J.; Abrahams, I. David
2010-11-01
In this article we attempt to clarify various notions regarding multiple point scattering. We consider several predictions for the effective material properties of an inhomogeneous slab region which can be derived from classical multiple scattering theories. In particular we are interested in the point scattering limit when wavelengths λ0 ≫ l ∼ a where l is the characteristic length-scale of the distance between inclusions and a is the characteristic length-scale of inclusions. In this limit we are able to derive effective properties which are physically valid for any volume fraction φ, except in the sound-soft scatterer case where there is a condition on the size of φ. We shall confine attention to random distributions of inclusions and employ the Quasi-Crystalline Approximation to yield results. In particular we discuss the different scenarios of acoustics and antiplane elasticity and stress the reciprocity between these two problems which means that they can be solved simultaneously. We make various statements regarding the efficacy of the various multiple scattering theories in the prediction of effective material properties in the quasi-static limit.
Effects of subsurface volume scattering on the lunar microwave brightness temperature spectrum
Keihm, S. J.
1982-01-01
The effects of volumetric scattering on the lunar microwave brightness temperature are examined for a broad range of feasible lunar rock population distributions. Mie-scattering phase functions and the radiative transfer method are utilized. Surveyor and Apollo data relevant to lunar rock size distributions are discussed, and parameters are chosen for nine scattering models which liberally cover the range of studied rock population distributions. Scattering model brightness temperature predictions are analyzed in terms of the lunar disk center emission averaged over a lunation for wavelengths of 3-30 cm. The effects of scattering on the amplitude of disk center brightness temperature variations and resultant deductions of regolith electrical loss are examined. Constraints on the global scale variability of subsurface scatterers imposed by microwave brightness temperature maps are considered.
Coste, C; Lund, F; Coste, Christophe; Umeki, Makoto; Lund, Fernando
1999-01-01
When a surface wave interacts with a vertical vortex in shallow water the latter induces a dislocation in the incident wavefronts that is analogous to what happens in the Aharonov-Bohm effect for the scattering of electrons by a confined magnetic field. In addition to this global similarity between these two physical systems there is scattering. This paper reports a detailed calculation of this scattering, which is quantitatively different from the electronic case in that a surface wave penetrates the inside of a vortex while electrons do not penetrate a solenoid. This difference, together with an additional difference in the equations that govern both physical systems lead to a quite different scattering in the case of surface waves, whose main characteristic is a strong asymmetry in the scattering cross section. The assumptions and approximations under which these effects happen are carefully considered, and their applicability to the case of scattering of acoustic waves by vorticity is noted.
Support scattering effects on low-gain satellite antenna pattern measurements
Appel-Hansen, Jørgen
1973-01-01
The purpose of the present investigation is to determine the difference between the scattering effects from two types of supports on satellite antenna pattern measurements. The difference in scattering effects is estimated by comparing low-gain antenna patterns recorded when using a foam tower an...
Aharonov-Bohm effect on Aharonov-Casher scattering
Lin, Qiong-Gui
2010-01-01
The scattering of relativistic spin-1/2 neutral particles with a magnetic dipole moment by a long straight charged line and a magnetic flux line at the same position is studied. The scattering cross sections for unpolarized and polarized particles are obtained by solving the Dirac-Pauli equation. The results are in general the same as those for pure Aharonov-Casher scattering (by the charged line alone) as expected. However, in special cases when the incident energy, the line charge density, and the magnetic flux satisfy some relations, the cross section for polarized particles is dramatically changed. Relations between the polarization of incident particles and that of scattered ones are presented, both in the full relativistic case and the nonrelativistic limit. The characteristic difference between the general and special cases lies in the backward direction: in the general cases the incident particles are simply bounced while in the special cases their polarization is turned over simultaneously. For pure Aharonov-Casher scattering there exist cases where the helicities of all scattered particles are reversed. This seems to be remarkable but appears unnoticed previously. Two mathematical approaches are employed to deal with the singularity of the electric and magnetic field and it turns out that the physical results are essentially the same.
Global effects of moon phase on nocturnal acoustic scattering layers
Prihartato, PK
2016-01-18
© Inter-Research 2016. The impact of moon phase on the global nocturnal vertical distribution of acoustic scattering layers (SLs) in the upper 200 m was studied during the Malaspina expedition that circumnavigated the world. We assessed the nocturnal weighted mean depths and the vertical extension of the SL (the range between the upper 25th percentile and lower 75th percentile of the backscatter) and used a generalized additive model to reveal the relationship between the nocturnal vertical distribution of the SL and moon phase, as well as other environmental factors. Moon phase significantly affected the SL distribution on a global scale, in contrast to other factors such as dissolved oxygen, temperature and fluorescence, which each correlated with nocturnal SL distribution during the large geographic coverage. Full moon caused a deepening effect on the nocturnal SL. Contrary to expectations, the shallowest distribution was not observed during the darkest nights (new moon) and there was no difference in vertical distribution between new moon and intermediate moon phases. We conclude that the trend of deepening SL during approximately full moon (bright nights) is a global phenomenon related to anti-predator behavior.
Radiative effects in scattering of polarized leptons by polarized nucleons and light nuclei
Akushevich, I V; Shumeiko, N M
2001-01-01
Recent developments in the field of radiative effects in polarized lepton-nuclear scattering are reviewed. The processes of inclusive, semi-inclusive, diffractive and elastic scattering are considered. The explicit formulae obtained within the covariant approach are discussed. FORTRAN codes POLRAD, RADGEN, HAPRAD, DIFFRAD and MASCARAD created on the basis of the formulae are briefly described. Applications for data analysis of the current experiments on lepton-nuclear scattering at CERN, DESY, SLAC and TJNAF are illustrated by numerical results.
Image degradation due to scattering effects in two-mirror telescopes
Harvey, James E.; Krywonos, Andrey; Peterson, Gary; Bruner, Marilyn
2010-06-01
Image degradation due to scattered radiation is a serious problem in many short-wavelength (x-ray and EUV) imaging systems. Most currently available image analysis codes require the scattering behavior [data on the bidirectional scattering distribution function (BSDF)] as input in order to calculate the image quality from such systems. Predicting image degradation due to scattering effects is typically quite computation-intensive. If using a conventional optical design and analysis code, each geometrically traced ray spawns hundreds of scattered rays randomly distributed and weighted according to the input BSDF. These scattered rays must then be traced through the system to the focal plane using nonsequential ray-tracing techniques. For multielement imaging systems even the scattered rays spawn more scattered rays at each additional surface encountered in the system. In this paper we describe a generalization of Peterson's analytical treatment of in-field stray light in multielement imaging systems. In particular, we remove the smooth-surface limitation that ignores the scattered-scattered radiation, which can be quite large for EUV wavelengths even for state-of-the-art optical surfaces. Predictions of image degradation for a two-mirror EUV telescope with the generalized Peterson model are then numerically validated with the much more computation-intensive ZEMAX® and ASAP® codes.
A Novel Simulator of Nonstationary Random MIMO Channels in Rayleigh Fading Scenarios
Qiuming Zhu
2016-01-01
Full Text Available For simulations of nonstationary multiple-input multiple-output (MIMO Rayleigh fading channels in time-variant scattering environments, a novel channel simulator is proposed based on the superposition of chirp signals. This new method has the advantages of low complexity and implementation simplicity as the sum of sinusoids (SOS method. In order to reproduce realistic time varying statistics for dynamic channels, an efficient parameter computation method is also proposed for updating the frequency parameters of employed chirp signals. Simulation results indicate that the proposed simulator is effective in generating nonstationary MIMO channels with close approximation of the time-variant statistical characteristics in accordance with the expected theoretical counterparts.
Ultraslow-light effects in symmetric and asymmetric waveguide structures with moon-like scatterers
Wan, Yong; Ge, Xiao-Hui; Xu, Sheng; Guo, Yue; Yuan, Feng
2017-02-01
Ultraslow-light effects in two-dimensional hexagonal-lattice coupled waveguide with moon-like scatterers were theoretically studied using the plane-wave expansion method. For symmetric structures, simulations showed that slow light with high group index can be achieved by shifting the scatterers and adjusting the radius of moon-like scatterers. The maximum group index was over 8:0 × 104. For asymmetric structures, simulations showed that slow light with flat band and high group index can be obtained by shifting the scatterers, adjusting the radius of moon-like scatterers, and rotating the scatterers. The maximum group index was over 5:7 × 105 with a "saddle-like" relationship between the frequency and group index.
Superstructures in Rayleigh-Benard convection
Stevens, Richard; Verzicco, Roberto; Lohse, Detlef
2016-11-01
We study the heat transfer and the flow structures in Rayleigh-Bénard convection as function of the Rayleigh number Ra and the aspect ratio. We consider three-dimensional direct numerical simulations (DNS) in a laterally periodic geometry with aspect ratios up to Γ =Lx /Lz =Ly /Lz = 64 at Ra =108 , where Lx and Ly indicate the horizontal domain sizes and Lz the height. We find that the heat transport convergences relatively quickly with increasing aspect ratio. In contrast, we find that the large scale flow structures change significantly with increasing aspect ratio due to the formation of superstructures. For example, at Ra =108 we find the formation of basically only one large scale circulation roll in boxes with an aspect ratio up to 8. For larger boxes we find the formation of multiple of these extremely large convection rolls. We illustrate this by movies of horizontal cross-section of the bulk and the boundary layer and analyze them by using spectra in the boundary layer and the bulk. In addition, we study the effect of the large scale flow structures on the mean and higher order temperature and velocity statistics in the boundary layer and the bulk by comparing the simulation results obtained in different aspect ratio boxes. Foundation for fundamental Research on Matter (FOM), Netherlands Center for Multiscale Catalytic Energy Conversion (MCEC), SURFsara, Gauss Large Scale project.
Hybrid Rayleigh, Raman and TPE fluorescence spectral confocal microscopy of living cells
Pully, V.V.; Lenferink, Aufrid T.M.; Otto, Cornelis
2010-01-01
A hybrid fluorescence–Raman confocal microscopy platform is presented, which integrates low-wavenumber-resolution Raman imaging, Rayleigh scatter imaging and two-photon fluorescence (TPE) spectral imaging, fast ‘amplitude-only’ TPE-fluorescence imaging and high-spectral-resolution Raman imaging.
Kostorz, G. [Eidgenoessische Technische Hochschule, Angewandte Physik, Zurich (Switzerland)
1996-12-31
While Bragg scattering is characteristic for the average structure of crystals, static local deviations from the average lattice lead to diffuse elastic scattering around and between Bragg peaks. This scattering thus contains information on the occupation of lattice sites by different atomic species and on static local displacements, even in a macroscopically homogeneous crystalline sample. The various diffuse scattering effects, including those around the incident beam (small-angle scattering), are introduced and illustrated by typical results obtained for some Ni alloys. (author) 7 figs., 41 refs.
Color effects from scattering on random surface structures in dielectrics
Clausen, Jeppe; Christiansen, Alexander B; Garnæs, Jørgen;
2012-01-01
We show that cheap large area color filters, based on surface scattering, can be fabricated in dielectric materials by replication of random structures in silicon. The specular transmittance of three different types of structures, corresponding to three different colors, have been characterized....... The angle resolved scattering has been measured and compared to predictions based on the measured surface topography and by the use of non-paraxial scalar diffraction theory. From this it is shown that the color of the transmitted light can be predicted from the topography of the randomly textured surfaces....
Experimental determination of the effective refractive index in strongly scattering media
Gómez Rivas, J.; Gomez Rivas, J.; Hau, D.H.; Imhof, A.; Sprik, R.; Bret, B.P.J.; Johnson, P.M.; Hijmans, T.W.; Lagendijk, Aart
2003-01-01
Measurements of the angular-resolved-optical transmission through strongly scattering samples of porous gallium phosphide are described. Currently porous GaP is the strongest-scattering material for visible light. From these measurements the effective refractive index and the average reflectivity at
Pilny, Lukas; Bissacco, Giuliano; De Chiffre, Leonardo
The effect of angular orientation of a scattered light sensor with respect to main curvature and surface lay on roughness measurements is evaluated. A commercial scattered light sensor OS 500-32 from Optosurf GmbH was used. The investigation was performed on polished cylindrical surfaces with cro...
Serre, J.; Ghazali, A.; Hugon, P. Leroux
1981-02-01
Using a self-consistent multiple-scattering method, we estimate the relative importance of both effects of scattering and of impurity-concentration fluctuations on band states in heavily doped semiconductors and thus we account for band tailing. We apply this formalism to the estimate of the interband absorption spectrum in a typical case, in satisfactory agreement with experiment.
A Simple Capacity Formula for Correlated Diversity Rayleigh Fading Channels
CHENG Xing-qing; SU Shu-chun; LI Dao-ben
2004-01-01
Abstract: The system capacity can be considerably increased if we appropriately exploit the randomness of multipath propagation. A simple average capacity formula is derived for correlated diversity Rayleigh fading channels through linear transformation method.Numerical results that illustrate the effect of correlation parameter and diversity order on the diversitycapacity are also presented.
Off-shell and nonlocal effects in proton-nucleus elastic scattering
Picklesimer, A.; Tandy, P.C.; Thaler, R.M.; Wolfe, D.H.
1984-04-01
The influence of off-shell and nonlocal effects in the first-order nonrelativistic microscopic optical potential is investigated for elastic proton scattering above 100 MeV. With the free nucleon-nucleon t matrix taken from the model of Love and Franey, these effects are significant only for scattering angles greater than about 60/sup 0/ and energies below about 300 MeV. The inadequacy of the standard first-order theory for predictions of spin observables at forward scattering angles remains unchanged when these effects are included and the need for higher order processes including medium and relativistic effects is reinforced.
Off-shell and nonlocal effects in proton-nucleus elastic scattering
Picklesimer, A.; Tandy, P. C.; Thaler, R. M.; Wolfe, D. H.
1984-04-01
The influence of off-shell and nonlocal effects in the first-order nonrelativistic microscopic optical potential is investigated for elastic proton scattering above 100 MeV. With the free nucleon-nucleon t matrix taken from the model of Love and Franey, these effects are significant only for scattering angles greater than about 60° and energies below about 300 MeV. The inadequacy of the standard first-order theory for predictions of spin observables at forward scattering angles remains unchanged when these effects are included and the need for higher order processes including medium and relativistic effects is reinforced.
Optical scattering in glass ceramics
Mattarelli, M.; Montagna, M.; Verrocchio, P.
2008-01-01
The transparency of glass ceramics with nanocrystals is generally higher than that expected from the theory of Rayleigh scattering. We attribute this ultra-transparency to the spatial correlation of the nanoparticles. The structure factor is calculated for a simple model system, the random sequentia
Asymptotic Rayleigh instantaneous unit hydrograph
Troutman, B.M.; Karlinger, M.R.
1988-01-01
The instantaneous unit hydrograph for a channel network under general linear routing and conditioned on the network magnitude, N, tends asymptotically, as N grows large, to a Rayleigh probability density function. This behavior is identical to that of the width function of the network, and is proven under the assumption that the network link configuration is topologically random and the link hydraulic and geometric properties are independent and identically distributed random variables. The asymptotic distribution depends only on a scale factor, {Mathematical expression}, where ?? is a mean link wave travel time. ?? 1988 Springer-Verlag.
Tsui, Po-Hsiang; Wan, Yung-Liang; Huang, Chih-Chung; Wang, Ming-Chen
2010-10-01
The Nakagami parameter is associated with the Nakagami distribution estimated from ultrasonic backscattered signals and closely reflects the scatterer concentrations in tissues. There is an interest in exploring the possibility of enhancing the ability of the Nakagami parameter to characterize tissues. In this paper, we explore the effect of adaptive thresholdfiltering based on the noise-assisted empirical mode decomposition of the ultrasonic backscattered signals on the Nakagami parameter as a function of scatterer concentration for improving the Nakagami parameter performance. We carried out phantom experiments using 5 MHz focused and nonfocused transducers. Before filtering, the dynamic ranges of the Nakagami parameter, estimated using focused and nonfocused transducers between the scatterer concentrations of 2 and 32 scatterers/mm3, were 0.44 and 0.1, respectively. After filtering, the dynamic ranges of the Nakagami parameter, using the focused and nonfocused transducers, were 0.71 and 0.79, respectively. The experimental results showed that the adaptive threshold filter makes the Nakagami parameter measured by a focused transducer more sensitive to the variation in the scatterer concentration. The proposed method also endows the Nakagami parameter measured by a nonfocused transducer with the ability to differentiate various scatterer concentrations. However, the Nakagami parameters estimated by focused and nonfocused transducers after adaptive threshold filtering have different physical meanings: the former represents the statistics of signals backscattered from unresolvable scatterers while the latter is associated with stronger resolvable scatterers or local inhomogeneity due to scatterer aggregation.
Effects of Multiple Photon Scattering in Deciduous Tree Canopies
2009-12-01
SCATTERING IN DECIDUOUS TREE CANOPIES 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62204F 6. AUTHOR(S...where mh 18= , 16132.0 −= mLm , and 85.0=hzm . Note that the value for mL corresponds to our own experimental results, as will be described in Section 4
The polarization effect of a laser in multiphoton Compton scattering
Liang, Guo-Hua; Lü, Qing-Zheng; Teng, Ai-Ping; Li, Ying-Jun
2014-05-01
The multiphoton Compton scattering in a high-intensity laser beam is studied by using the laser-dressed quantum electrodynamics (QED) method, which is a non-perturbative theory for the interaction between a plane electromagnetic field and a charged particle. In order to analyze in the real experimental condition, a Lorentz transformation for the cross section of this process is derived between the laboratory frame and the initial rest frame of electrons. The energy of the scattered photon is analyzed, as well as the cross sections for different laser intensities and polarizations and different electron velocities. The angular distribution of the emitted photon is investigated in a special velocity of the electron, in which for a fixed number of absorbed photons, the electron energy will not change after the scattering in the lab frame. We obtain the conclusion that higher laser intensities suppress few-laser-photon absorption and enhance more-laser-photon absorption. A comparison between different polarizations is also made, and we find that the linearly polarized laser is more suitable to generate nonlinear Compton scattering.
Sakievich, Philip; Peet, Yulia; Adrian, Ronald
2016-11-01
At high Rayleigh numbers in moderate aspect-ratio cylindrical domains turbulent Rayleigh-Bénard convection (RBC) exhibits coherent large-scale motions with patterns like some of those found in laminar flow. In this work we show how the patterns of the largest scales in turbulent RBC affect the bias and convergence of the flow statistics at aspect-ratio 6.3 (diameter/ height). Large scale motions influence two of the finite-time statistical mean's inherent properties: 1) the orientation of the patterns changes so slowly that it may appear almost fixed during a finite averaging time interval, thereby imbedding a preferred azimuthal direction in the sampled data; 2) they also have at least two states associated with the occurrence of up and down motions near the center of the convection cell. We will present a novel technique for triggering additional states of RBC in DNS simulations that are targeted for improving the statistical convergence of the flow. This technique gently perturbs the flow so that the new variations of the large scale patterns can be sampled. Funding through U. S. National Science Foundation Grants CBET-1335731, CMMI-1250124 and XSEDE research allocation TG-CTS150039.
Electrodynamics of surface-enhanced Raman scattering
Adles, E J; Aspnes, D E
2011-01-01
We examine SERS from two perspectives: as a phenomenon described by the Laplace Equation (the electrostatic or Rayleigh limit) and by the Helmholtz Equation (electrodynamic or Mie limit). We formulate the problem in terms of the scalar potential, which simplifies calculations without introducing approximations. Because scattering is not usually calculated this way, we provide the necessary theoretical justification showing that the scalar-potential description is complete. Additional simplifications result from treating the scatterer as a point charge q instead of a dipole. This allows us to determine the consequences of including the longitudinal (Coulomb) interaction between q and a passive resonator. This interaction suppresses the mathematical singularities that lead to the unphysical resonant infinities in first and second enhancements. It also modifies the effective restoring-force constant of a resonant denominator, which permits us to explore the possibility of dual resonance through a molecular pathw...
Characterization of the angular memory effect of scattered light in biological tissues
Schott, Sam; Léger, Jean-Francois; Bourdieu, Laurent; Gigan, Sylvain
2015-01-01
High resolution optical microscopy is essential in neuroscience but suffers from scattering in biological tissues. It therefore grants access to superficial layers only. Recently developed techniques use scattered photons for imaging by exploiting angular correlations in transmitted light and could potentially increase imaging depths. But those correlations (`angular memory effect') are of very short range and, in theory, only present behind and not inside scattering media. From measurements on neural tissues and complementary simulations, we find that strong forward scattering in biological tissues can enhance the memory effect range (and thus the possible field-of-view) by more than an order of magnitude compared to isotropic scattering for $\\sim$1\\,mm thick tissue layers.
Characterization of the angular memory effect of scattered light in biological tissues
Schott, Sam; Bertolotti, Jacopo; Léger, Jean-Francois; Bourdieu, Laurent; Gigan, Sylvain
2015-05-01
High resolution optical microscopy is essential in neuroscience but suffers from scattering in biological tissues. It therefore grants access to superficial layers only. Recently developed techniques use scattered photons for imaging by exploiting angular correlations in transmitted light and could potentially increase imaging depths. But those correlations (`angular memory effect') are of very short range and, in theory, only present behind and not inside scattering media. From measurements on neural tissues and complementary simulations, we find that strong forward scattering in biological tissues can enhance the memory effect range (and thus the possible field-of-view) by more than an order of magnitude compared to isotropic scattering for $\\sim$1\\,mm thick tissue layers.
Characterization of the angular memory effect of scattered light in biological tissues.
Schott, Sam; Bertolotti, Jacopo; Léger, Jean-Francois; Bourdieu, Laurent; Gigan, Sylvain
2015-05-18
High resolution optical microscopy is essential in neuroscience but suffers from scattering in biological tissues and therefore grants access to superficial brain layers only. Recently developed techniques use scattered photons for imaging by exploiting angular correlations in transmitted light and could potentially increase imaging depths. But those correlations ('angular memory effect') are of a very short range and should theoretically be only present behind and not inside scattering media. From measurements on neural tissues and complementary simulations, we find that strong forward scattering in biological tissues can enhance the memory effect range and thus the possible field-of-view by more than an order of magnitude compared to isotropic scattering for ∼1 mm thick tissue layers.
Strong Coulomb scattering effects on low frequency noise in monolayer WS2 field-effect transistors
Joo, Min-Kyu; Yun, Yoojoo; Yun, Seokjoon; Lee, Young Hee; Suh, Dongseok
2016-10-01
When atomically thin semiconducting transition metal dichalcogenides are used as a channel material, they are inevitably exposed to supporting substrates. This situation can lead to masking of intrinsic properties by undesired extrinsic doping and/or additional conductance fluctuations from the largely distributed Coulomb impurities at the interface between the channel and the substrate. Here, we report low-frequency noise characteristics in monolayer WS2 field-effect transistors on silicon/silicon-oxide substrate. To mitigate the effect of extrinsic low-frequency noise sources, a nitrogen annealing was carried out to provide better interface quality and to suppress the channel access resistance. The carrier number fluctuation and the correlated mobility fluctuation (CNF-CMF) model was better than the sole CNF one to explain our low-frequency noise data, because of the strong Coulomb scattering effect on the effective mobility caused by carrier trapping/detrapping at oxide traps. The temperature-dependent field-effect mobility in the four-probe configuration and the Coulomb scattering parameters are presented to support this strong Coulomb scattering effect on carrier transport in monolayer WS2 field-effect transistor.
Multiphase Rayleigh-Bénard convection
Oresta, P.; Fornarelli, F.; Prosperetti, Andrea
2014-01-01
Numerical simulations of two-phase Rayleigh-Bénard convection in a cylindrical cell with particles or vapor bubbles suspended in the fluid are described. The particles or bubbles are modeled as points, the Rayleigh number is 2×106 and the fluids considered are air, for the particle case, and
Electron gyroharmonic effects on ionospheric stimulated Brillouin scatter
Mahmoudian, A.; Scales, W. A.; Bernhardt, P. A.; Isham, B.; Kendall, E.; Briczinski, S. J.; Fuentes, N. E. B.; Vega-Cancel, O.
2014-08-01
Stimulated Brillouin scattering (SBS) and resonant phenomena are well known in the context of laser fusion, fiber optics, and piezoelectric semiconductor plasmas, as well as in various biological applications. Due to recent advances, active space experiments using high-power high-frequency (HF) radio waves may now produce stimulated Brillouin scattering (SBS) in the ionospheric plasma. The sensitivity of the narrowband SBS emission lines to pump frequency stepping across electron gyroharmonics is reported here for the first time. Experimental observations show that SBS emission sidebands are suppressed as the HF pump frequency is stepped across the second and third electron gyroharmonics. A correlation of artificially enhanced airglow and SBS emission lines excited at the upper hybrid altitude is observed and studied for second gyroharmonic heating. The SBS behavior near electron gyroharmonics is shown to have important diagnostic applications for multilayered, multi-ion component plasmas such as the ionosphere.
Effective Spectral Function for Quasielastic Scattering on Nuclei
Bodek, A; Coopersmith, B
2014-01-01
Spectral functions that are used in neutrino event generators (such as GENIE, NEUT, NUANCE, NUWRO, and GiBUU) to model quasielastic(QE) scattering from nuclear targets include Fermi gas, Local Thomas Fermi gas (LTF), Bodek-Ritche Fermi gas with high momentum tail, and the Benhar Fantoni two dimensional spectral function. We find that the predictions of these spectral functions for the $\\frac{d\\sigma}{d\
Effect of nonstoichiometry on Raman scattering of VO2 films
Yuan Hong-Tao; Feng Ke-Cheng; Wang Xue-Jin; Li Chao; He Chen-Juan; Nie Yu-Xin
2004-01-01
@@ We report on Raman scattering of VO2 films prepared by radio frequency magnetron sputtering under different conditions. Our investigations revealed that the dominated Raman peaks shift towards high frequency for both V-rich and O-rich VO2 films, compared with the stoichiometry VO2 films. The experimental evidence is presented and the cause for nonstoichiometry dependence of Raman spectra of VO2 films is discussed.
Array gain for a cylindrical array with baffle scatter effects.
Bertilone, Derek C; Killeen, Damien S; Bao, Chaoying
2007-11-01
Cylindrical arrays used in sonar for passive underwater surveillance often have sensors surrounding a cylindrical metal baffle. In some operational sonars, the phones in each stave (i.e., each line of phones aligned with the cylinder axis) are hardwired together so that the array is equivalent to a baffled circular array of directional elements, where each element corresponds to a line array of omnidirectional phones steered to broadside. In this paper a model is introduced for computing the array gain of such an array at high frequencies, which incorporates baffle scatter using infinite, rigid cylinder scattering theory, and with ambient noise described by an angular spectral density function. In practice the phones are often offset from the baffle surface, and the acoustic field sampled by the staves is distorted at high frequencies due to interference between the incident and scattered fields. Examples are given to illustrate the resulting array gain degradation, using three noise distributions that are frequently used in sonar performance modeling: three-dimensional isotropic, two-dimensional isotropic, and surface dipole noise.
Crystal effects in the neutralization of He+ ions in the low energy ion scattering regime.
Primetzhofer, D; Markin, S N; Juaristi, J I; Taglauer, E; Bauer, P
2008-05-30
Investigating possible crystal effects in ion scattering from elemental surfaces, measurements of the positive ion fraction P+ are reported for He+ ions scattered from single and polycrystalline Cu surfaces. In the Auger neutralization regime, the ion yield is determined by scattering from the outermost atomic layer. For Cu(110) P+ exceeds that for polycrystalline Cu by up to a factor of 2.5, thus exhibiting a strong crystal effect. It is much less pronounced at higher energies, i.e., in the reionization regime. However, there a completely different angular dependence of the ion yield is observed for poly- and single crystals, due to massive subsurface contributions in nonchanneling directions.
SIMULATION OF THE Ku-BAND RADAR ALTIMETER SEA ICE EFFECTIVE SCATTERING SURFACE
Tonboe, Rasmus; Andersen, Søren; Pedersen, Leif Toudal
2006-01-01
A radiative transfer model is used to simulate the sea ice radar altimeter effective scattering surface variability as a function of snow depth and density. Under dry snow conditions without layering these are the primary snow parameters affecting the scattering surface variability. The model...... is initialised with in situ data collected during the May 2004 GreenIce ice camp in the Lincoln Sea (73ºW; 85ºN). Our results show that the snow cover is important for the effective scattering surface depth in sea ice and thus for the range measurement, ice freeboard and ice thickness estimation....
Effects Of Aerosol And Multiple Scattering On The Polarization Of The Twilight Sky
Ugolnikov, O S; Maslov, I A
2003-01-01
The paper contains the review of a number of wide-angle polarization CCD-measurements of the twilight sky in V and R color bands with effective wavelengths equal to 550 and 700 nm. The basic factors effecting (usually decreasing) on the polarization of the twilight sky are the atmospheric aerosol scattering and multiple scattering. The method of multiple scattering separation is being considered. The results are compared with the data of numerical simulation of radiation transfer in the atmosphere for different aerosol models. The whole twilight period is divided on the different stages with different mechanisms forming the twilight sky polarization properties.
Properties of Differential Scattering Section Based on Multi-photon Nonlinear Compton Effect
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.
Anelastic Rayleigh-Taylor mixing layers
Schneider, N.; Gauthier, S.
2016-07-01
Anelastic Rayleigh-Taylor mixing layers for miscible fluids are investigated with a recently built model (Schneider and Gauthier 2015 J. Eng. Math. 92 55-71). Four Chebyshev-Fourier-Fourier direct numerical simulations are analyzed. They use different values for the compressibility parameters: Atwood number (the dimensionless difference of the heavy and light fluid densities) and stratification (accounts for the vertical variation of density due to gravity). For intermediate Atwood numbers and finite stratification, compressibility effects quickly occurs. As a result only nonlinear behaviours are reached. The influence of the compressibility parameters on the growth speed of the RTI is discussed. The 0.1—Atwood number/0.4—stratification configuration reaches a turbulent regime. This turbulent mixing layer is analyzed with statistical tools such as moments, PDFs, anisotropy indicators and spectra.
Strong coupling effects in near-barrier heavy-ion elastic scattering
Keeley, N. [National Centre for Nuclear Research, Otwock (Poland); Kemper, K.W. [The Florida State University, Department of Physics, Tallahassee, Florida (United States); University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Rusek, K. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland)
2014-09-15
Accurate elastic scattering angular distribution data measured at bombarding energies just above the Coulomb barrier have shapes that can markedly differ from or be the same as the expected classical Fresnel scattering pattern depending on the structure of the projectile, the target or both. Examples are given such as {sup 18}O + {sup 184}W and {sup 16}O + {sup 148,} {sup 152}Sm, where the expected rise above Rutherford scattering due to Coulomb-nuclear interference is damped by coupling to the target excited states, and the extreme case of {sup 11}Li scattering, where coupling to the {sup 9}Li + n + n continuum leads to an elastic scattering shape that cannot be reproduced by any standard optical model parameter set. An early indication that the projectile structure can modify the elastic scattering angular distribution was the large vector analyzing powers observed in polarised {sup 6}Li scattering. The recent availability of high-quality {sup 6}He, {sup 11}Li and {sup 11}Be data provides further examples of the influence that coupling effects can have on elastic scattering. Conditions for strong projectile-target coupling effects are presented with special emphasis on the importance of the beam-target charge combination being large enough to bring about the strong coupling effects. Several measurements are proposed that can lead to further understanding of strong coupling effects by both inelastic excitation and nucleon transfer on near-barrier elastic scattering. A final note on the anomalous nature of {sup 8}B elastic scattering is presented as it possesses a more or less normal Fresnel scattering shape whereas one would a priori not expect this due to the very low breakup threshold of {sup 8}B. The special nature of {sup 11}Li is presented as it is predicted that no matter how far above the Coulomb barrier the elastic scattering is measured, its shape will not appear as Fresnel like whereas the elastic scattering of all other loosely bound nuclei studied to
Asymmetrically pumped Bragg scattering with the effects of nonlinear phase modulation
Andersen, Lasse Mejling; Friis, Søren Michael Mørk; Reddy, Dileep V.
2014-01-01
We derive exact solutions to asymmetrically pumped Bragg scattering with nonlinear phase-modulation (NPM) and show that this setup allows for the frequency conversion of many temporal modes, while reducing the effects due to NPM.......We derive exact solutions to asymmetrically pumped Bragg scattering with nonlinear phase-modulation (NPM) and show that this setup allows for the frequency conversion of many temporal modes, while reducing the effects due to NPM....
Automatically identifying scatter in fluorescence data using robust techniques
Engelen, S.; Frosch, Stina; Hubert, M.
2007-01-01
is developed based on robust statistical methods. The method does not demand any visual inspection of the data prior to modeling, and can handle first and second order Rayleigh scatter as well as Raman scatter in various types of EEM data. The results of the automated scatter identification method were used......First and second order Rayleigh and Raman scatter is a common problem when fitting Parallel Factor Analysis (PARAFAC) to fluorescence excitation-emission data (EEM). The scatter does not contain any relevant chemical information and does not conform to the low-rank trilinear model. The scatter...... as input data for three different PARAFAC methods. Firstly inserting missing values in the scatter regions are tested, secondly an interpolation of the scatter regions is performed and finally the scatter regions are down-weighted. These results show that the PARAFAC method to choose after scatter...
Experimental Investigation of Scattering from Randomly Rough Plastic Cylinders
1992-09-01
fluid, here following the form from Morse and Ingard [20] and Skudrzyk [21]. First, the adiabatic equation of state relating the pressure, p, and...wavelength, we get the standard relation between the particle velocity and the pressure u = -VP. (2.6) Rayleigh [19] and Morse and Ingard [20] derive the...the internal and scattered fields, Rayleigh [191 and Morse and Ingard [20] solve for the scattered field from an infinitely long circular cylinder by
Berginc, G.
2013-11-01
We have developed a general formalism based on Green's functions to calculate the coherent electromagnetic field scattered by a random medium with rough boundaries. The approximate expression derived makes it possible to determine the effective permittivity, which is generalised for a layer of an inhomogeneous random medium with different types of particles and bounded with randomly rough interfaces. This effective permittivity describes the coherent propagation of an electromagnetic wave in a random medium with randomly rough boundaries. We have obtained an expression, which contains the Maxwell - Garnett formula at the low-frequency limit, and the Keller formula; the latter has been proved to be in good agreement with experiments for particles whose dimensions are larger than a wavelength.
Collet, Remo; Hayek, Wolfgang; Asplund, Martin
2011-08-01
We study the effects of different approximations of scattering in 3D radiation-hydrodynamics simulations on the photospheric temperature stratification of metal-poor red giant stars. We find that assuming a Planckian source function and neglecting the contribution of scattering to extinction in optically thin layers provides a good approximation of the effects of coherent scattering on the photospheric temperature balance.
Seismic metasurfaces: Sub-wavelength resonators and Rayleigh wave interaction
Colquitt, D J; Craster, R V; Roux, P; Guenneau, S R L
2016-01-01
We consider the canonical problem of an array of rods, which act as resonators, placed on an elastic substrate; the substrate being either a thin elastic plate or an elastic half-space. In both cases the flexural plate, or Rayleigh surface, waves in the substrate interact with the resonators to create interesting effects such as effective band-gaps for surface waves or filters that transform surface waves into bulk waves; these effects have parallels in the field of optics where such sub-wavelength resonators create metamaterials, and metasurfaces, in the bulk and at the surface respectively. Here we carefully analyse this canonical problem by extracting the dispersion relations analytically thereby examining the influence of both the flexural and compressional resonances on the propagating wave. For an array of resonators atop an elastic half-space we augment the analysis with numerical simulations. Amongst other effects, we demonstrate the striking effect of a dispersion curve that transitions from Rayleigh...
Artemyev, A. V., E-mail: ante0226@gmail.com [Space Research Institute, RAS, Moscow (Russian Federation); Mourenas, D.; Krasnoselskikh, V. V. [LPC2E/CNRS - University of Orleans, Orleans (France); Agapitov, O. V. [Space Sciences Laboratory, University of California, Berkeley, California 94720 (United States)
2015-06-15
In this paper, we study relativistic electron scattering by fast magnetosonic waves. We compare results of test particle simulations and the quasi-linear theory for different spectra of waves to investigate how a fine structure of the wave emission can influence electron resonant scattering. We show that for a realistically wide distribution of wave normal angles θ (i.e., when the dispersion δθ≥0.5{sup °}), relativistic electron scattering is similar for a wide wave spectrum and for a spectrum consisting in well-separated ion cyclotron harmonics. Comparisons of test particle simulations with quasi-linear theory show that for δθ>0.5{sup °}, the quasi-linear approximation describes resonant scattering correctly for a large enough plasma frequency. For a very narrow θ distribution (when δθ∼0.05{sup °}), however, the effect of a fine structure in the wave spectrum becomes important. In this case, quasi-linear theory clearly fails in describing accurately electron scattering by fast magnetosonic waves. We also study the effect of high wave amplitudes on relativistic electron scattering. For typical conditions in the earth's radiation belts, the quasi-linear approximation cannot accurately describe electron scattering for waves with averaged amplitudes >300 pT. We discuss various applications of the obtained results for modeling electron dynamics in the radiation belts and in the Earth's magnetotail.
Suppression of the low spatial frequency effects of scattered radiation in digital radiography
Kotre, C. J.
2016-01-01
One of the deleterious effects of scattered radiation in the digital radiograph is to add a slowly varying background to the image. This can reduce the ability of the observer to discern low contrast signals if the background gradient over a signal feature prevents the use of a small enough display window to make the signal visible. This paper presents an image processing scheme for suppressing the low spatial frequency effects of scattered radiation in digital radiography and demonstrates it on a range of clinical and phantom images. The approach relies on the approximate separation of high atomic number bony features from the low atomic number soft tissue background, and the use of forward convolution with a scatter kernel to produce an estimate of the scatter distribution arising from the soft tissue background. This is then scaled by an estimate of the soft tissue scatter fraction and subtracted from the original image to produce the final scatter-suppressed image. The implementation employs many approximations in order to make use of information that is readily available in the image headers of current x-ray imaging systems. The performance of the image processing scheme is demonstrated on phantom and clinical images. It is argued that clinical application of the approach could employ a user-controlled scatter subtraction step that would reduce any risk of misinterpretation of the processed image.
Superradiant Forward Scattering in Multiple Scattering
Chabe, Julien; Bienaime, Tom; Bachelard, Romain; Piovella, Nicola; Kaiser, Robin
2012-01-01
We report on an interference effect in multiple scattering by resonant scatterers resulting in enhanced forward scattering, violating Ohm's law for photons. The underlying mechanism of this wave effect is superradiance, which we have investigated using cold atoms as a toy model. We present numerical and experimental evidences for this superradiant forward scattering, which is robust against disorder and configuration averaging.
Scattering effect of submarine hull on propeller non-cavitation noise
Wei, Yingsan; Shen, Yang; Jin, Shuanbao; Hu, Pengfei; Lan, Rensheng; Zhuang, Shuangjiang; Liu, Dezhi
2016-05-01
This paper investigates the non-cavitation noise caused by propeller running in the wake of submarine with the consideration of scattering effect caused by submarine's hull. The computation fluid dynamics (CFD) and acoustic analogy method are adopted to predict fluctuating pressure of propeller's blade and its underwater noise radiation in time domain, respectively. An effective iteration method which is derived in the time domain from the Helmholtz integral equation is used to solve multi-frequency waves scattering due to obstacles. Moreover, to minimize time interpolation caused numerical errors, the pressure and its derivative at the sound emission time is obtained by summation of Fourier series. It is noted that the time averaging algorithm is used to achieve a convergent result if the solution oscillated in the iteration process. Meanwhile, the developed iteration method is verified and applied to predict propeller noise scattered from submarine's hull. In accordance with analysis results, it is summarized that (1) the scattering effect of hull on pressure distribution pattern especially at the frequency higher than blade passing frequency (BPF) is proved according to the contour maps of sound pressure distribution of submarine's hull and typical detecting planes. (2) The scattering effect of the hull on the total pressure is observable in noise frequency spectrum of field points, where the maximum increment is up to 3 dB at BPF, 12.5 dB at 2BPF and 20.2 dB at 3BPF. (3) The pressure scattered from hull is negligible in near-field of propeller, since the scattering effect surrounding analyzed location of propeller on submarine's stern is significantly different from the surface ship. This work shows the importance of submarine's scattering effect in evaluating the propeller non-cavitation noise.
Filtered Rayleigh Scattering Measurements in a Buoyant Flowfield
2007-03-01
graph in Figure 35 have a Reynolds number of 238 and a Grashof number of 1242. The referenced literature of Law et al, 2003, and Satyanarayana and...and is consistent with the literature (Law et al., 2003 and Satyanarayana and Jaluria, 1982). A key advantage for using the time averaged image to...Journal, Vol. 44, No. 7, pp. 1505-1515. Satyanarayana , S. and Jaluria, Yogesh. (1982), “A Study of Laminar Buoyant Jets Discharged at an
Filtered Rayleigh Scattering Measurements in a Buoyant Flow Field
2008-03-01
In order to perform the division operations necessary in Eq. (8), the matricies are first converted to single precision values. The background...50 background images, 50 laser-only images, and 50 helium flow images are manipulated as matricies by Matlab, and an example result is displayed
Effect of the third π ∗ resonance on the angular distributions for electron-pyrimidine scattering
Mašín, Zdeněk; Gorfinkiel, Jimena D.
2016-07-01
We present a detailed analysis of the effect of the well known third π∗ resonance on the angular behaviour of the elastic cross section in electron scattering from pyrimidine. This resonance, occurring approximately at 4.7 eV, is of mixed shape and core-excited character. Experimental and theoretical results show the presence of a peak/dip behaviour in this energy range, that is absent for other resonances. Our investigations show that the cause of the peak/dip is an interference of background p-wave to p-wave scattering amplitudes with the amplitudes for resonant scattering. The equivalent resonance in pyrazine shows the same behaviour and the effect is therefore likely to appear in other benzene-like molecules. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.
Meyer, S. S.; Jeffries, A. D.; Weiss, R.
1983-01-01
It is believed that X-ray emission from clusters of galaxies represents thermal bremsstrahlung from a hot plasma. According to Sunyaev and Zel'dovich (1972), the plasma column density and temperature derived from this model imply a measurable distortion of the cosmic background radiation (CBR) in the cluster direction. This distortion results from the Compton scattering of the CBR photons by the electrons in the plasma, resulting in an average increase of each photon. This process, known as the Sunyaev-Zel'dovich effect, is photon conserving and 'shifts' the CBR spectrum to higher frequencies. The result is a decrease of flux at frequencies below 7.5 per cm (the Rayleigh-Jeans region), and an increase above. The investigation is concerned with measurements of the Sunyaev-Zel'dovich effect at frequencies in the range from 3 to 10 per cm. Attention is given to the employed observing and analysis technique, and an initial null result for the cluster Abell 1795.
The investigation of the Coulomb breakup effect on the 6-He elastic scattering
Kucuk, Yasemin; Boztosun, Ismail [Erciyes University, Department of Physics, Kayseri (Turkey); Keeley, Nicholas [Andrzej Soltan Institute, Department of Nuclear Reactions (Poland)
2009-07-01
The elastic scattering of the halo nuclei from the heavier target exhibits a different behavior from the standart Fresnel-type diffraction at energies near the Coulomb barrier. In this paper, we have performed the CDCC calculations for 6-He elastic scattering from the different targets to investigate the effect of the Coulomb breakup coupling and we have observed that the deviation from the standard diffraction behavior due to strong breakup coupling starts at around ZT= 60.
Kiss, Annamaria; Kuramoto, Yoshio; Hoshino, Shintaro
2011-01-01
Accurate numerical results are derived for transport properties of Kondo impurity systems with potential scattering and orbital degeneracy. Using the continuous-time quantum Monte Carlo (CT-QMC) method, static and dynamic physical quantities are derived in a wide temperature range across the Kondo temperature T_K. With strong potential scattering, the resistivity tends to decrease with decreasing temperature, in contrast to the ordinary Kondo effect. Correspondingly, the quasi-particle densit...
Partial Wave Analysis of Scattering with Nonlocal Aharonov-Bohm Effect
Lin, H
2003-01-01
Partial wave analysis of two dimensional scattering for an arbitray short range potential and a nonlocal Aharonov-Bohm magnetic flux is established. The nonlocal influence of magnetic flux in the cross section of scattering for hard disk with a magnetic flux is examined. Due to the ergodic property of the nonlocal effect such influence would occur in quite general potential system and may be useful in understanding phenomenon of mesoscopic phyiscs.
Abel Palafox
2014-01-01
Full Text Available We address a prototype inverse scattering problem in the interface of applied mathematics, statistics, and scientific computing. We pose the acoustic inverse scattering problem in a Bayesian inference perspective and simulate from the posterior distribution using MCMC. The PDE forward map is implemented using high performance computing methods. We implement a standard Bayesian model selection method to estimate an effective number of Fourier coefficients that may be retrieved from noisy data within a standard formulation.
Temperature effects on multi-particle scattering in a gapped quantum magnet
Notbohm, S.; Tennant, D. A.; Lake, B.; Canfield, P. C.; Fielden, J.; Kögerler, P.; Mikeska, H.-J.; Luckmann, C.; Telling, M. T. F.
2007-03-01
We report measurements of the temperature effects on the dimerized antiferromagnetic chain material, copper nitrate Cu(NO3)2·2.5D2O. Using inelastic neutron scattering we have measured the temperature dependence of the one- and two-magnon excitation spectra as well as the temperature induced one-magnon intra-band scattering in a single crystal. Comparison is made with numerical evaluations of thermal averages based on the calculation for a chain of 16 spins.
Neutron Angular Scatter Effects in 3DHZETRN: Quasi-Elastic
Wilson, John W.; Werneth, Charles M.; Slaba, Tony C.; Badavi, Francis F.; Reddell, Brandon D.; Bahadori, Amir A.
2017-01-01
The current 3DHZETRN code has a detailed three dimensional (3D) treatment of neutron transport based on a forward/isotropic assumption and has been compared to Monte Carlo (MC) simulation codes in various geometries. In most cases, it has been found that 3DHZETRN agrees with the MC codes to the extent they agree with each other. However, a recent study of neutron leakage from finite geometries revealed that further improvements to the 3DHZETRN formalism are needed. In the present report, angular scattering corrections to the neutron fluence are provided in an attempt to improve fluence estimates from a uniform sphere. It is found that further developments in the nuclear production models are required to fully evaluate the impact of transport model updates. A model for the quasi-elastic neutron production spectra is therefore developed and implemented into 3DHZETRN.
Analysis of beam plasma instability effects on incoherent scatter spectra
M. A. Diaz
2010-12-01
Full Text Available Naturally Enhanced Ion Acoustic Lines (NEIALs detected with Incoherent Scatter Radars (ISRs can be produced by a Langmuir decay mechanism, triggered by a bump on tail instability. A recent model of the beam-plasma instability suggests that weak-warm beams, such those associated with NEIAL events, might produce Langmuir harmonics which could be detected by a properly configured ISR. The analysis performed in this work shows that such a beam-driven wave may be simultaneously detected with NEIALs within the baseband signal of a single ISR. The analysis shows that simultaneous detection of NEIALs and the first Langmuir harmonic is more likely than simultaneous detection of NEIALs and enhanced plasma line. This detection not only would help to discriminate between current NEIAL models, but could also aid in the parameter estimation of soft precipitating electrons.
Sharma, A.; Janssen, N. M. A.; Mathijssen, S. G. J.; de Leeuw, D. M.; Kemerink, M.; Bobbert, P. A.
2011-03-01
We investigate the effect of Coulomb scattering from trapped charges on the mobility in the two-dimensional channel of an organic field-effect transistor. The number of trapped charges can be tuned by applying a prolonged gate bias. Surprisingly, after increasing the number of trapped charges to a level where strong Coulomb scattering is expected, the mobility has decreased only slightly. Simulations show that this can be explained by assuming that the trapped charges are located in the gate dielectric at a significant distance from the channel instead of in or very close to the channel. The effect of Coulomb scattering is then strongly reduced.
Overview of Rayleigh-Taylor instability
Sharp, D.H.
1983-01-01
The aim of this talk is to survey Rayleigh-Taylor instability, describing the phenomenology that occurs at a Taylor unstable interface, and reviewing attempts to understand these phenomena quantitatively.
Strong coupling effects in near-barrier heavy-ion elastic scattering
Keeley, N; Rusek, K
2014-01-01
Accurate elastic scattering angular distribution data measured at bombarding energies just above the Coulomb barrier have shapes that can markedly differ from or be the same as the expected classical Fresnel scattering pattern depending on the structure of the projectile, the target or both. Examples are given such as 18O + 184W and 16O + 148,152Sm where the expected rise above Rutherford scattering due to Coulomb-nuclear interference is damped by coupling to the target excited states, and the extreme case of 11Li scattering, where coupling to the 9Li + n + n continuum leads to an elastic scattering shape that cannot be reproduced by any standard optical model parameter set. The recent availability of high quality 6He, 11Li and 11Be data provides further examples of the influence that coupling effects can have on elastic scattering. Conditions for strong projectile-target coupling effects are presented with special emphasis on the importance of the beam-target charge combination being large enough to bring ab...
22 MeV polarized proton scattering from 40Ca and effective NN interactions
无
2000-01-01
Analyzing powers and differential cross sections have been measured for elastic scattering of 22 MeV polarized protons from 40Ca, 16O and 12C, and diferential cross sections for inelastic scattering of 22 MeV protons from 3- (3.736 MeV)and 5-(4.491 MeV) states of 40Ca have also been measured. The experimental data for polarized proton elastic scattering have been analyzed with a phenomenological optical potential parameters, the experimental data and theoretical values are in good agreement. In the theoretical frame of microscopic single scattering model, transition densities extracted from electron inelastic scattering and M3Y and Halderson’s effective interactions have been utilized to analyze the experimental data of 22 MeV proton inelastic scattering from 40Ca. Overall, it seems that Halderson’s effective interaction can better describe the experimental data than M3Y although the degree of agreement between experimental and theoretical values needs to be improved.
Core-shell colloidal particles with dynamically tunable scattering properties.
Meng, Guangnan; Manoharan, Vinothan N; Perro, Adeline
2017-09-27
We design polystyrene-poly(N'-isopropylacrylamide-co-acrylic acid) core-shell particles that exhibit dynamically tunable scattering. We show that under normal solvent conditions the shell is nearly index-matched to pure water, and the particle scattering is dominated by Rayleigh scattering from the core. As the temperature or salt concentration increases, both the scattering cross-section and the forward scattering increase, characteristic of Mie scatterers. The magnitude of the change in the scattering cross-section and scattering anisotropy can be controlled through the solvent conditions and the size of the core. Such particles may find use as optical switches or optical filters with tunable opacity.
Jeffrey, D.J. (Oklahoma Univ., Norman (USA))
1989-12-01
The Sobolev-P method, a generalization of the Sobolev method, is developed for the treatment of the polarization state of radiation and the polarizing effect of resonance line scattering. The polarization state of the radiation is described by the Stokes parameters. The photon angular redistribution is described by a linear combination of the Rayleigh and isotropic phase matrices. Using this form of photon redistribution the Sobolev-P method formulas are derived for the case of axisymmetric systems. For continuum radiative transfer it is shown that quantitatively accurate calculations can be done using the Sobolev-P method and a discretized continuous opacity approximation. Sample synthetic flux and polarization spectra for model axisymmetric supernova systems calculated using Sobolev-P method are reported. A comparison of these sample results with spectropolarimetric data for SN 1987A shows some qualitative agreement of the features and indicates that it is pausible that SN 1987A has a length-width asymmetry of order 20 percent. 68 refs.
王文星; 黄玉萍; 徐淑坤
2011-01-01
以没食子酸为还原剂和稳定剂,用种子生长法制备出粒径均匀、单分散性和稳定性好、近球形的Ag/Au 核壳纳米粒子.高分辨透射电镜(HRTEM)与 X-射线能量色散光谱仪(EDX)测试表明,在Ag/Au摩尔比为1:1.6时,Au已完全包裹在Ag纳米粒子表面时,平均粒径为25 nm.以此摩尔比制备的Ag/Au核壳纳米粒子为探针用共振瑞利散射光谱测定人血清总蛋白,在NaAc-HAc缓冲液(pH 4.4)及0.05 mol/L NaCl介质中,Ag/Au核壳纳米粒子与HSA形成稳定的复合物;Ag/Au-HSA纳米复合物的相对散射强度ΔI390 nm与HSA浓度在0.0011～0.35 mg/L范围内呈线性关系,其回归方程为ΔI390 nm＝-0.54+494.82c(r＝0.9994),检出限为0.36 μg/L.本方法有较好的选择性,可用于人血清蛋白分析,结果与考马斯亮蓝G-250法一致,回收率在98.2%～102.3%之间,相对标准偏差为2.3%.%Nearly spherical Ag/Au core/shell nanoparticles with good monodispersity and stability were synthesized in aqueous solution by seed growth method using gallic acid as reductant and stabilizer. High resolution transmission electron microscopic (HRTEM) image and energy dispersive X-ray spectrometry (EDX) showed complete coating of gold on the surface of Ag nanoparticles and the presence of Au and Ag in individual nanoparticle with the average size of about 25 nm. The Ag/Au core/shell nanoparticles with Au/Ag molar ratio of 1:1.6 were used as probes to determine human serum proteins by resonance Rayleigh scattering (RRS) spectrometry. The results indicated that in pH 4.4 NaAc-HAc buffer solutions and in the presence of NsC1 of 0.05 mol/L, HSA was combined with Ag/Au core/shell nanoparticles to form stable complex. The enhanced resonance scattering intensity at 390 nm (△I390nm) was linear to HSA concentration in the range of 0. 0011-0.35 mg/L, with the regress equation of △I390nm = -0. 54+494. 82C(r＝ 0. 994) and the detection limit of 0.36 μg/L.Co-existing metal ions and amino acids
Rayleigh-Taylor mixing in supernova experiments
Swisher, N. C.; Abarzhi, S. I., E-mail: snezhana.abarzhi@gmail.com [Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Kuranz, C. C. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Arnett, D. [University of Arizona, Tucson, Arizona 85721 (United States); Hurricane, O.; Remington, B. A.; Robey, H. F. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
2015-10-15
We report a scrupulous analysis of data in supernova experiments that are conducted at high power laser facilities in order to study core-collapse supernova SN1987A. Parameters of the experimental system are properly scaled to investigate the interaction of a blast-wave with helium-hydrogen interface, and the induced Rayleigh-Taylor instability and Rayleigh-Taylor mixing of the denser and lighter fluids with time-dependent acceleration. We analyze all available experimental images of the Rayleigh-Taylor flow in supernova experiments and measure delicate features of the interfacial dynamics. A new scaling is identified for calibration of experimental data to enable their accurate analysis and comparisons. By properly accounting for the imprint of the experimental conditions, the data set size and statistics are substantially increased. New theoretical solutions are reported to describe asymptotic dynamics of Rayleigh-Taylor flow with time-dependent acceleration by applying theoretical analysis that considers symmetries and momentum transport. Good qualitative and quantitative agreement is achieved of the experimental data with the theory and simulations. Our study indicates that in supernova experiments Rayleigh-Taylor flow is in the mixing regime, the interface amplitude contributes substantially to the characteristic length scale for energy dissipation; Rayleigh-Taylor mixing keeps order.
Multiple Scattering and Visco-Thermal Effects on 2D Phononic Crystal
Duclos, Aroune; Pagneux, Vincent
2008-01-01
In this paper, we are interested in the transition between regimes here either visco-thermal or multiple scattering effects dominate for the propagation of acoustic waves through a 2D regular square array of rigid cylinders embedded in air. An extension of the numerical method using Schl\\"omilch series is performed in order to account for visco-thermal losses. Comparison withexperimental data and results from classical homogenization theory allows to study the transition between a low frequency limit (where viscous and thermal effects dominate) and a high frequency regime (where multiple scattering effects become predominant). For this particular geometry, a large frequency domain where visco-thermal and multiple scattering effects coexist is found.
Near-critical-angle scattering for the characterization of clouds of bubbles: particular effects.
Onofri, Fabrice R A; Krzysiek, Mariusz A; Barbosa, Séverine; Messager, Valérie; Ren, Kuan-Fang; Mroczka, Janusz
2011-10-20
We report experimental investigations on the influence of various optical effects on the far-field scattering pattern produced by a cloud of optical bubbles near the critical scattering angle. Among the effects considered, there is the change of the relative refractive index of the bubbles (gas bubbles or some liquid-liquid droplets), the influence of intensity gradients induced by the laser beam intensity profile and by the spatial filtering of the collection optics, the coherent and multiple scattering effects occurring for densely packed bubbles, and the tilt angle of spheroidal optical bubbles. The results obtained herein are thought to be fundamental for the development of future works to model these effects and for the extension of the range of applicability of an inverse technique (referenced herein as the critical angle refractometry and sizing technique), which is used to determine the size distribution and composition of bubbly flows.
Neutron scattering effects on fusion ion temperature measurements.
Ziegler, Lee (Bechtel/Nevada, Las Vegas, NV); Starner, Jason R.; Cooper, Gary Wayne; Ruiz, Carlos L.; Franklin, James Kenneth (Ktech Corporation, Albuquerque, NM); Casey, Daniel T.
2006-06-01
To support the nuclear fusion program at Sandia National Laboratories (SNL), a consistent and verifiable method to determine fusion ion temperatures needs to be developed. Since the fusion temperature directly affects the width in the spread of neutron energies produced, a measurement of the neutron energy width can yield the fusion temperature. Traditionally, the spread in neutron energies is measured by using time-of-flight to convert a spread in neutron energies at the source to a spread in time at detector. One potential obstacle to using this technique at the Z facility at SNL is the need to shield the neutron detectors from the intense bremsstrahlung produced. The shielding consists of eight inches of lead and the concern is that neutrons will scatter in the lead, artificially broaden the neutron pulse width and lead to an erroneous measurement. To address this issue, experiments were performed at the University of Rochester's Laboratory for Laser Energetics, which demonstrated that a reliable ion temperature measurement can be achieved behind eight inches of lead shielding. To further expand upon this finding, Monte Carlo N-Particle eXtended (MCNPX) was used to simulate the experimental geometric conditions and perform the neutron transport. MCNPX was able to confidently estimate results observed at the University of Rochester.
Incoherent subharmonic light scattering in isotropic media.
Feng, D H; Xu, Z Z; Feng, X L; Jia, T Q; Li, X X; Liu, J S
2005-02-01
Incoherent subharmonic light scattering in isotropic media is a new kind of nonlinear light scattering, which involves single input photon and multiple output photons of equal frequency. We investigate theoretically the dependence of the subharmonic scattering intensity on the hyperpolarizability of molecules and the incident intensity using nonlinear optics theory similar to that used for Hyper-Rayleigh scattering and degenerate optical parametric oscillators. It is derived that the subharmonic scattering intensities grow exponentially or superexponentially with the hyperpolarizability of molecules and the incident intensity.
Parametrics Resonances of a Forced Modified Rayleigh-Duffing Oscillator
Miwadinou, C H; Chabi, J B
2013-01-01
We investigate in this paper the superharmonic and subharmonic resonances of forced modified Rayleigh-Duffing oscillator. We analyse this equation by method of multiple scales and we obtain superharmonic and subharmonic resonances order-two and order-three. We obtain also regions where steady-state subharmonic responses exist. Finally, we use the amplitude-frequency curve for demonstrate the effect of various parameters on the response of the system.
Extrinsic spin Hall effect induced by resonant skew scattering in graphene.
Ferreira, Aires; Rappoport, Tatiana G; Cazalilla, Miguel A; Castro Neto, A H
2014-02-14
We show that the extrinsic spin Hall effect can be engineered in monolayer graphene by decoration with small doses of adatoms, molecules, or nanoparticles originating local spin-orbit perturbations. The analysis of the single impurity scattering problem shows that intrinsic and Rashba spin-orbit local couplings enhance the spin Hall effect via skew scattering of charge carriers in the resonant regime. The solution of the transport equations for a random ensemble of spin-orbit impurities reveals that giant spin Hall currents are within the reach of the current state of the art in device fabrication. The spin Hall effect is robust with respect to thermal fluctuations and disorder averaging.
Micro-Doppler Effect of Extended Streamlined Targets Based on Sliding Scattering Centre Model
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.
Effects of Raman scattering and attenuation in silica fiber-based parametric frequency conversion
Friis, Søren Michael Mørk; Andersen, Lasse Mejling; Rottwitt, Karsten
2017-01-01
Four-wave mixing in the form of Bragg scattering (BS) has been predicted to enable quantum noise-less frequency conversion by analytic quantum approaches. Using a semi-classical description of quantum noise that accounts for loss and stimulated and spontaneous Raman scattering, which are not curr......Four-wave mixing in the form of Bragg scattering (BS) has been predicted to enable quantum noise-less frequency conversion by analytic quantum approaches. Using a semi-classical description of quantum noise that accounts for loss and stimulated and spontaneous Raman scattering, which...... are not currently described in existing quantum approaches, we quantify the impacts of these effects on the conversion efficiency and on the quantum noise properties of BS in terms of an induced noise figure (NF). We give an approximate closed-form expression for the BS conversion efficiency that includes loss...... and stimulated Raman scattering, and we derive explicit expressions for the Raman-induced NF from the semi-classical approach used here. We find that Raman scattering induces a NF in the BS process that is comparable to the 3-dB NF associated with linear amplifiers...
Mitri, F G
2016-12-01
The goal of this work is to demonstrate the emergence of a spin torque singularity (i.e. zero spin torque) and a spin rotation reversal of a small Rayleigh lipid/fat viscous fluid sphere located arbitrarily in space in the field of an acoustical Bessel vortex beam. This counter-intuitive property of negative spin torque generation suggests a direction of spin rotation in opposite handedness of the angular momentum carried by the incident beam. Such effects may open new capabilities in methods of quantitative characterization to determine physical properties such as viscosity, viscoelasticity, compressibility, stiffness, etc., and other techniques for the rotation and positioning using acoustical tractor beams and tweezers, invisibility cloaks, and acoustically-engineered composite metamaterials to name a few examples. Based on the descriptions for the velocity potential of the incident beam and the scattering coefficients of the sphere in the long-wavelength approximation limit, simplified expressions for the spin and orbital radiation torque components are derived. For beams with (positive or negative) unit topological charge (m=±1), the axial spin torque component for a Rayleigh absorptive sphere is maximal at the center of the beam, while it vanishes for |m|>1 therein. Moreover, the longitudinal orbital torque component, causing the sphere to rotate around the center of the beam is evaluated based on the mathematical decomposition using the gradient, scattering and absorption transverse radiation force vector components. It is shown that there is no contribution of the gradient transverse force to the orbital torque, which is only caused by the scattering and absorption transverse force components. Though the incident acoustical vortex beam carrying angular momentum causes the sphere to rotate in the same orbital direction of the beam handedness, it induces a spin torque singularity (i.e. zero spin torque) and subsequent sign reversal. This phenomenon of
REVISITING THE SCATTERING GREENHOUSE EFFECT OF CO{sub 2} ICE CLOUDS
Kitzmann, D., E-mail: daniel.kitzmann@csh.unibe.ch [Center for Space and Habitability, University of Bern, Sidlerstr. 5, 3012 Bern (Switzerland)
2016-02-01
Carbon dioxide ice clouds are thought to play an important role for cold terrestrial planets with thick CO{sub 2} dominated atmospheres. Various previous studies showed that a scattering greenhouse effect by carbon dioxide ice clouds could result in a massive warming of the planetary surface. However, all of these studies only employed simplified two-stream radiative transfer schemes to describe the anisotropic scattering. Using accurate radiative transfer models with a general discrete ordinate method, this study revisits this important effect and shows that the positive climatic impact of carbon dioxide clouds was strongly overestimated in the past. The revised scattering greenhouse effect can have important implications for the early Mars, but also for planets like the early Earth or the position of the outer boundary of the habitable zone.
Rayleigh Waves in a Rotating Orthotropic Micropolar Elastic Solid Half-Space
Baljeet Singh
2013-01-01
Full Text Available A problem on Rayleigh wave in a rotating half-space of an orthotropic micropolar material is considered. The governing equations are solved for surface wave solutions in the half space of the material. These solutions satisfy the boundary conditions at free surface of the half-space to obtain the frequency equation of the Rayleigh wave. For numerical purpose, the frequency equation is approximated. The nondimensional speed of Rayleigh wave is computed and shown graphically versus nondimensional frequency and rotation-frequency ratio for both orthotropic micropolar elastic and isotropic micropolar elastic cases. The numerical results show the effects of rotation, orthotropy, and nondimensional frequency on the nondimensional speed of the Rayleigh wave.
Remarks on the Rayleigh-Benard Convection on Spherical Shells
Wang, Shouhong
2011-01-01
The main objective of this article is to study the effect of spherical geometry on dynamic transitions and pattern formation for the Rayleigh-Benard convection. The study is mainly motivated by the importance of spherical geometry and convection in geophysical flows. It is shown in particular that the system always undergoes a continuous (Type-I) transition to a $2l_c$-dimensional sphere $S^{2lc}$, where lc is the critical wave length corresponding to the critical Rayleigh number. Furthermore, it has shown in [12] that it is critical to add nonisotropic turbulent friction terms in the momentum equation to capture the large-scale atmospheric and oceanic circulation patterns. We show in particular that the system with turbulent friction terms added undergoes the same type of dynamic transition, and obtain an explicit formula linking the critical wave number (pattern selection), the aspect ratio, and the ratio between the horizontal and vertical turbulent friction coefficients.
Hu, Bo, E-mail: hubo2011@semi.ac.cn
2015-03-15
The effect of surface polar optical phonons (SOs) from the dielectric layers on electron mobility in dual-gated graphene field effect transistors (GFETs) is studied theoretically. By taking into account SO scattering of electron as a main scattering mechanism, the electron mobility is calculated by the iterative solution of Boltzmann transport equation. In treating scattering with the SO modes, the dynamic dielectric screening is included and compared to the static dielectric screening and the dielectric screening in the static limit. It is found that the dynamic dielectric screening effect plays an important role in the range of low net carrier density. More importantly, in-plane acoustic phonon scattering and charged impurity scattering are also included in the total mobility for SiO{sub 2}-supported GFETs with various high-κ top-gate dielectric layers considered. The calculated total mobility results suggest both Al{sub 2}O{sub 3} and AlN are the promising candidate dielectric layers for the enhancement in room temperature mobility of graphene in the future.
Lobachevsky, Pavel; Ivashkevich, Alesia; Forrester, Helen B; Stevenson, Andrew W; Hall, Chris J; Sprung, Carl N; Martin, Olga A
2015-12-01
Synchrotron radiation is an excellent tool for investigating bystander effects in cell and animal models because of the well-defined and controllable configuration of the beam. Although synchrotron radiation has many advantages for such studies compared to conventional radiation, the contribution of dose exposure from scattered radiation nevertheless remains a source of concern. Therefore, the influence of scattered radiation on the detection of bystander effects induced by synchrotron radiation in biological in vitro models was evaluated. Radiochromic XRQA2 film-based dosimetry was employed to measure the absorbed dose of scattered radiation in cultured cells at various distances from a field exposed to microbeam radiotherapy and broadbeam X-ray radiation. The level of scattered radiation was dependent on the distance, dose in the target zone and beam mode. The number of γ-H2AX foci in cells positioned at the same target distances was measured and used as a biodosimeter to evaluate the absorbed dose. A correlation of absorbed dose values measured by the physical and biological methods was identified. The γ-H2AX assay successfully quantitated the scattered radiation in the range starting from 10 mGy and its contribution to the observed radiation-induced bystander effect.
Low frequency sound scattering from spherical assemblages of bubbles using effective medium theory.
Hahn, Thomas R
2007-12-01
The determination of the acoustic field scattered by an underwater assembly of gas bubbles or similar resonant monopole scatterers is of considerable theoretical and practical interest. This problem is addressed from a theoretical point of view within the framework of the effective medium theory for the case of spherically shaped assemblages. Although being valid more generally, the effective medium theory is an ideal instrument to study multiple scattering effects such as low frequency collective resonances, acoustically coupled breathing modes of the entire assembly. Explicit expressions for the scattering amplitude and cross sections are derived, as well as closed form expressions for the resonance frequency and spectral shape of the fundamental collective mode utilizing analytical S-matrix methods. This approach allows, in principle, a simultaneous inversion for the assembly radius and void fraction directly from the scattering cross sections. To demonstrate the validity of the approach, the theory is applied to the example of idealized, spherically shaped schools of swim bladder bearing fish. The analytic results of the theory are compared to numerical first-principle benchmark computations and excellent agreement is found, even for densely packed schools and frequencies across the bladder resonance.
Dossou, Kokou B
2016-01-01
By applying the properties of Fabry-Perot resonance and Rayleigh anomaly, we have showed that a photonic crystal slab can scatter the light from an incident plane wave into a diffracted light with a very large reflection or transmission coefficient. The enhanced field is either a propagating diffraction order (with a grazing angle of diffraction) or a weakly evanescent order, so it can be particularly useful for applications requiring an enhanced propagating field (or an enhanced field with a low attenuation). An efficient effective medium technique is developed for the design of the resonant photonic crystal slabs. Numerical simulations have shown that photonic crystal slabs with low index contrast, such as the ones found in the cell wall of diatoms, can enhance the intensity of the incident light by four orders of magnitude.
Zhao, Junlei; Xiao, Fei; Zhao, Haoxin; Dai, Yun; Zhang, Yudong
2017-01-01
Higher-order aberrations (HOAs) and intraocular scatter lead to the degradation of image quality on the retina, and consequently deteriorate subjective visual performance. In this article, we modified an adaptive optics double-pass system to combine objective and subjective visual testing capabilities. Employing the modified DP system, we investigated the effects of HOAs and intraocular scatter on contrast sensitivity. Contrast sensitivity measurements were performed with HOAs either retained or corrected by adaptive optics, and with scatter either remaining at the natural eye-induced level or further enhanced by a set of three different scatter filters. Contrast sensitivity was found to be worse when HOAs were uncorrected or scatter increased. Quantitative analysis indicated that the joint effect of HOAs and scatter on contrast sensitivity was not a simple summation of each contributing factor, suggesting a potential compensatory mechanism between HOAs and intraocular scatter on contrast sensitivity. PMID:28736660
The effects of substrate phonon mode scattering on transport in carbon nanotubes.
Perebeinos, Vasili; Rotkin, Slava V; Petrov, Alexey G; Avouris, Phaedon
2009-01-01
Carbon nanotubes (CNTs) have large intrinsic carrier mobility due to weak acoustic phonon scattering. However, unlike two-dimensional metal-oxide-semiconductor field effect transistors (MOSFETs), substrate surface polar phonon (SPP) scattering has a dramatic effect on the CNTFET mobility, due to the reduced vertical dimensions of the latter. We find that for the van der Waals distance between CNT and an SiO2 substrate, the low-field mobility at room temperature is reduced by almost an order of magnitude depending on the tube diameter. We predict additional experimental signatures of the SPP mechanism in dependence of the mobility on density, temperature, tube diameter, and CNT-substrate separation.
Effect of boron doping on first-order Raman scattering in superconducting boron doped diamond films
Kumar, Dinesh; Chandran, Maneesh; Ramachandra Rao, M. S.
2017-05-01
Aggregation of impurity levels into an impurity band in heavily boron doped diamond results in a background continuum and discrete zone centre phonon interference during the inelastic light scattering process. In order to understand the Raman scattering effect in granular BDD films, systematically heavily doped samples in the semiconducting and superconducting regimes have been studied using the excitation wavelengths in the UV and visible regions. A comprehensive analysis of the Fano resonance effect as a function of the impurity concentrations and the excitation frequencies is presented. Various Raman modes available in BDD including signals from the grain boundaries are discussed.
Interfacial scattering effect on anomalous Hall effect in Ni/Au multilayers
Zhang, Qiang
2017-04-21
The effect of interfacial scattering on anomalous Hall effect (AHE) was studied in the ${{\\\\left(\\\\text{N}{{\\\\text{i}}_{\\\\frac{36}{n}~\\\\text{nm}}}/\\\\text{A}{{\\\\text{u}}_{\\\\frac{12}{n}~\\\\text{nm}}}\\ ight)}_{n}}$ multilayers. Field-dependent Hall resistivity was measured in the temperature range of 5–300 K with the magnetic field up to 50 kOe. The anomalous Hall resistivity (${{\\ ho}_{\\\\text{AHE}}}$ ) was enhanced by more than six times at 5 K from n = 1 to n = 12 due to the increased interfacial scattering, whereas the longitudinal resistivity (${{\\ ho}_{xx}}$ ) was increased nearly three times. A scaling relation ${{\\ ho}_{\\\\text{AHE}}}\\\\sim \\ ho _{xx}^{\\\\gamma}$ with $\\\\gamma =1.85$ was obtained for ${{\\ ho}_{\\\\text{AHE}}}$ and ${{\\ ho}_{xx}}$ measured at 5 K, indicating that the dominant mechanism(s) of the AHE in these multilayers should be side-jump or/and intrinsic in nature. The new scaling relation ${{\\ ho}_{\\\\text{AHE}}}=\\\\alpha {{\\ ho}_{xx0}}+\\\\beta \\ ho _{xx0}^{2}+b\\ ho _{xx}^{2}$ (Tian et al 2009 Phys. Rev. Lett. 103 087206) has been applied to our data to identify the origin of the AHE in this type of multilayer.
Rayleigh--Taylor spike evaporation
Schappert, G. T.; Batha, S. H.; Klare, K. A.; Hollowell, D. E.; Mason, R. J.
2001-09-01
Laser-based experiments have shown that Rayleigh--Taylor (RT) growth in thin, perturbed copper foils leads to a phase dominated by narrow spikes between thin bubbles. These experiments were well modeled and diagnosed until this '' spike'' phase, but not into this spike phase. Experiments were designed, modeled, and performed on the OMEGA laser [T. R. Boehly, D. L. Brown, R. S. Craxton , Opt. Commun. 133, 495 (1997)] to study the late-time spike phase. To simulate the conditions and evolution of late time RT, a copper target was fabricated consisting of a series of thin ridges (spikes in cross section) 150 {mu}m apart on a thin flat copper backing. The target was placed on the side of a scale-1.2 hohlraum with the ridges pointing into the hohlraum, which was heated to 190 eV. Side-on radiography imaged the evolution of the ridges and flat copper backing into the typical RT bubble and spike structure including the '' mushroom-like feet'' on the tips of the spikes. RAGE computer models [R. M. Baltrusaitis, M. L. Gittings, R. P. Weaver, R. F. Benjamin, and J. M. Budzinski, Phys. Fluids 8, 2471 (1996)] show the formation of the '' mushrooms,'' as well as how the backing material converges to lengthen the spike. The computer predictions of evolving spike and bubble lengths match measurements fairly well for the thicker backing targets but not for the thinner backings.
Rayleigh-Taylor instability simulations with CRASH
Chou, C.-C.; Fryxell, B.; Drake, R. P.
2012-03-01
CRASH is a code package developed for the predictive study of radiative shocks. It is based on the BATSRUS MHD code used extensively for space-weather research. We desire to extend the applications of this code to the study of hydrodynamically unstable systems. We report here the results of Rayleigh-Taylor instability (RTI) simulations with CRASH, as a necessary step toward the study of such systems. Our goal, motivated by the previous comparison of simulations and experiment, is to be able to simulate the magnetic RTI with self-generated magnetic fields produced by the Biermann Battery effect. Here we show results for hydrodynamic RTI, comparing the effects of different solvers and numerical parameters. We find that the early-time behavior converges to the analytical result of the linear theory. We observe that the late-time morphology is sensitive to the numerical scheme and limiter beta. At low-resolution limit, the growth of RTI is highly dependent on the setup and resolution, which we attribute to the large numerical viscosity at low resolution.
High Rayleigh number convection numerical experiments
Verzicco, Roberto
2002-03-01
temperature variance dissipations. The achieved results seem to support the idea that the observed transitional behaviors have to be attributed to the change in the topology of the mean flow rather than to a transition from a laminar to a turbulent state of the viscous boundary layers. Other issues accomplished by the simulation concern the study of the scaling properties of the turbulent quantities and length scales in terms of Ra. Finally, further details on the turbulence dynamics are obtained by the analysis of the power spectra and low order structure functions of both the temperature and the velocity components, computed from the numerical probes both within the bulk region and close to the walls. References Roche, PE; Castaing, B; Chabaud, B; Hebral, B. ``Observation of the 1/2 power law in Rayleigh-Benard convection'' Phys. Rev. E, 2001, 6304(4), p. 5303. Niemela, J.J.; Skrbek, L.; Sreenivasan, K.R. and Donnelly, R.J. ``Turbulent convection at very high Rayleigh numbers'' Nature, 405, 243-253 (11 May 2000). Verzicco, R. and Camussi, R. ``Prandtl number effects in convective turbulence'' J. of Fluid Mech., 383, (1999), 55-73.
Study of Rayleigh-backscattering induced coherence collapse in an asymmetric DFB FL sensor
Liu, Wen; Ma, Lina; Hu, Zhengliang; Feng, Ying; Yang, Huayong
2016-09-01
Rayleigh-back scattering induced coherence collapse of an asymmetric distributed feedback fiber laser (DFB FL) sensor is investigated using a composite cavity model. The coherence collapse threshold condition of the asymmetric DFB FL sensor is measured. The DFB FL sensor shows different dynamic behaviors in different pump configurations. According to the asymmetric behavior to the external optical feedback, a novel method to find the actual phase shift position of the asymmetric DFB FL sensor is presented.
Coste, C; Coste, Christophe; Lund, Fernando
1999-01-01
Previous results on the scattering of surface waves by vertical vorticity on shallow water are generalized to the case of dispersive water waves. Dispersion effects are treated perturbatively around the shallow water limit, to first order in the ratio of depth to wavelength. The dislocation of the incident wavefront, analogous to the Aharonov-Bohm effect, is still observed. At short wavelengths the scattering is qualitatively similar to the nondispersive case. At moderate wavelengths, however, there are two markedly different scattering regimes according to wether the capillary length is smaller or larger than depends both on phase and group velocity. The validity range of the calculation is the same as in the shallow water case: wavelengths small compared to vortex radius, and low Mach number. The implications of these limitations are carefully considered.
Ballistic Performance Study of Nanowire FET: Effect of Channel Materials and Phonon Scattering
Iztihad, Hossain Md.; Khan, Touhid; Sufian, Abu; Alam, Md. Nur Kutubul; Mollah, Md. Nurunnabi; Islam, Md. Rafiqul
2016-02-01
The ballistic performance of Si and Ge nanowire (NW) is compared in this study. Current-voltage characteristic is obtained by self-consistently solving the nonequilibrium Green’s function (NEGF) transport equation with Poisson’s equation. The result is obtained at ⟨001⟩ channel orientation. Simulation result shows Ge NW gives higher ON-state current than Si NW, when OFF-state current is made equal by gate metal work function engineering. However, at subthreshold region, performance of NW FET for both material is almost identical. The intravalley and intervalley electron-phonon scattering effect is also calculated using the deformation potential theory and the self-consistent Born approximation. It is found that electron-phonon scattering effect is more pronounced at ON-state of Si NW FET. The ballistic current decreases with the decrease in diameter of the Si NW FET due to electron-phonon scattering.
Artemyev, A. V., E-mail: ante0226@gmail.com; Vasiliev, A. A. [Space Research Institute, RAS, Moscow (Russian Federation); Mourenas, D.; Krasnoselskikh, V. V. [LPC2E/CNRS—University of Orleans, Orleans (France); Agapitov, O. V. [Space Sciences Laboratory, University of California, Berkeley, California 94720 (United States)
2014-10-15
In this paper, we consider high-energy electron scattering and nonlinear trapping by oblique whistler waves via the Landau resonance. We use recent spacecraft observations in the radiation belts to construct the whistler wave model. The main purpose of the paper is to provide an estimate of the critical wave amplitude for which the nonlinear wave-particle resonant interaction becomes more important than particle scattering. To this aim, we derive an analytical expression describing the particle scattering by large amplitude whistler waves and compare the corresponding effect with the nonlinear particle acceleration due to trapping. The latter is much more rare but the corresponding change of energy is substantially larger than energy jumps due to scattering. We show that for reasonable wave amplitudes ∼10–100 mV/m of strong whistlers, the nonlinear effects are more important than the linear and nonlinear scattering for electrons with energies ∼10–50 keV. We test the dependencies of the critical wave amplitude on system parameters (background plasma density, wave frequency, etc.). We discuss the role of obtained results for the theoretical description of the nonlinear wave amplification in radiation belts.
Quasi-Rayleigh waves in butt-welded thick steel plate
Kamas, Tuncay; Giurgiutiu, Victor; Lin, Bin
2015-03-01
This paper discusses theoretical and experimental analyses of weld guided surface acoustic waves (SAW) through the guided wave propagation (GWP) analyses. The GWP analyses have been carried out by utilizing piezoelectric wafer active sensors (PWAS) for in situ structural inspection of a thick steel plate with butt weld as the weld bead is ground flush. Ultrasonic techniques are commonly used for validation of welded structures in many in-situ monitoring applications, e.g. in off-shore structures, in nuclear and pressure vessel industries and in a range of naval applications. PWAS is recently employed in such ultrasonic applications as a resonator as well as a transducer. Quasi-Rayleigh waves a.k.a. SAW can be generated in relatively thick isotropic elastic plate having the same phase velocity as Rayleigh waves whereas Rayleigh waves are a high frequency approximation of the first symmetric (S0) and anti-symmetric (A0) Lamb wave modes. As the frequency becomes very high the S0 and the A0 wave speeds coalesce, and both have the same value. This value is exactly the Rayleigh wave speed and becomes constant along the frequency i.e. Rayleigh waves are non-dispersive guided surface acoustic waves. The study is followed with weld-GWP tests through the pitch-catch method along the butt weld line. The tuning curves of quasi-Rayleigh wave are determined to show the tuning and trapping effect of the weld bead that has higher thickness than the adjacent plates on producing a dominant quasi-Rayleigh wave mode. The significant usage of the weld tuned and guided quasi-Rayleigh wave mode is essentially discussed for the applications in the in-situ inspection of relatively thick structures with butt weld such as naval offshore structures. The paper ends with summary, conclusions and suggestions for future work.
Quasi-Rayleigh waves in butt-welded thick steel plate
Kamas, Tuncay, E-mail: kamas@email.sc.edu, E-mail: victorg@sc.edu, E-mail: linbin@cec.sc.edu; Giurgiutiu, Victor, E-mail: kamas@email.sc.edu, E-mail: victorg@sc.edu, E-mail: linbin@cec.sc.edu; Lin, Bin, E-mail: kamas@email.sc.edu, E-mail: victorg@sc.edu, E-mail: linbin@cec.sc.edu [Mechanical Engineering University of South Carolina, 300 Main Str., Columbia, SC 29208 (United States)
2015-03-31
This paper discusses theoretical and experimental analyses of weld guided surface acoustic waves (SAW) through the guided wave propagation (GWP) analyses. The GWP analyses have been carried out by utilizing piezoelectric wafer active sensors (PWAS) for in situ structural inspection of a thick steel plate with butt weld as the weld bead is ground flush. Ultrasonic techniques are commonly used for validation of welded structures in many in-situ monitoring applications, e.g. in off-shore structures, in nuclear and pressure vessel industries and in a range of naval applications. PWAS is recently employed in such ultrasonic applications as a resonator as well as a transducer. Quasi-Rayleigh waves a.k.a. SAW can be generated in relatively thick isotropic elastic plate having the same phase velocity as Rayleigh waves whereas Rayleigh waves are a high frequency approximation of the first symmetric (S0) and anti-symmetric (A0) Lamb wave modes. As the frequency becomes very high the S0 and the A0 wave speeds coalesce, and both have the same value. This value is exactly the Rayleigh wave speed and becomes constant along the frequency i.e. Rayleigh waves are non-dispersive guided surface acoustic waves. The study is followed with weld-GWP tests through the pitch-catch method along the butt weld line. The tuning curves of quasi-Rayleigh wave are determined to show the tuning and trapping effect of the weld bead that has higher thickness than the adjacent plates on producing a dominant quasi-Rayleigh wave mode. The significant usage of the weld tuned and guided quasi-Rayleigh wave mode is essentially discussed for the applications in the in-situ inspection of relatively thick structures with butt weld such as naval offshore structures. The paper ends with summary, conclusions and suggestions for future work.
Dirac sea effects in $K^+$ scattering from nuclei
Caillon, J C
1993-01-01
The ratio $R_T$ of $K^+-^{12}C$ to $K^+-d$ cross sections has been calculated microscopically using a boson-exchange $KN$ amplitude in which the $\\sigma$ and $\\omega$ mesons are dressed by the modifications of the Dirac sea in nuclear matter. In spite of the fact that this dressing leads to a scaling of the mesons effective mass in nuclear matter, the effect on the $R_T$ ratio is found to be weak.
Effect of Compton Scattering on the Electron Beam Dynamics at the ATF Damping Ring
Chaikovska, I; Delerue, N; Variola, A; Zomer, F; Kubo, K; Naito, T; Omori, T; Terunuma, N; Urakawa, J
2011-01-01
Compton scattering provides one of the most promising scheme to obtain polarized positrons for the next generation of $e^-$ -- $e^+$ colliders. Moreover it is an attractive method to produce monochromatic high energy polarized gammas for nuclear applications and X-rays for compact light sources. In this framework a four-mirror Fabry-P\\'erot cavity has been installed at the Accelerator Test Facility (ATF - KEK, Tsukuba, Japan) and is used to produce an intense flux of polarized gamma rays by Compton scattering \\cite{ipac-mightylaser}. For electrons at the ATF energy (1.28 GeV) Compton scattering may result in a shorter lifetime due to the limited bucket acceptance. We have implemented the effect of Compton scattering on a 2D tracking code with a Monte-Carlo method. This code has been used to study the longitudinal dynamics of the electron beam at the ATF damping ring, in particular the evolution of the energy spread and the bunch length under Compton scattering. The results obtained are presented and discussed...
Finite volume effects in low-energy neutron-deuteron scattering
Rokash, Alexander; Krebs, Hermann; Lee, Dean; Meißner, Ulf-G
2013-01-01
We present a lattice calculation of neutron-deuteron scattering at very low energies and investigate in detail the impact of the topological finite-volume corrections. Our calculations are carried out in the framework of pionless effective field theory at leading order in the low-energy expansion. Using lattice sizes and a lattice spacing comparable to those employed in nuclear lattice simulations, we find that the topological volume corrections must be taken into account in order to obtain correct results for the neutron-proton S-wave scattering lengths.
One phonon resonant Raman scattering in semiconductor quantum wires: Magnetic field effect
Betancourt-Riera, Re., E-mail: rbriera@posgrado.cifus.uson.mx [Instituto Tecnologico de Hermosillo, Avenida Tecnologico S/N, Colonia Sahuaro, C.P. 83170, Hermosillo, Sonor, (Mexico); Departamento de Investigacion en Fisica, Universidad de Sonora, Apartado Postal 5-088, C.P. 83190, Hermosillo, Sonora (Mexico); Betancourt-Riera, Ri. [Instituto Tecnologico de Hermosillo, Avenida Tecnologico S/N, Colonia Sahuaro, C.P. 83170, Hermosillo, Sonora (Mexico); Nieto Jalil, J.M. [Tecnologico de Monterrey-Campus Sonora Norte, Bulevar Enrique Mazon Lopez No. 965, C.P. 83000, Hermosillo, Sonora (Mexico); Riera, R. [Departamento de Investigacion en Fisica, Universidad de Sonora, Apartado Postal 5-088, C.P. 83190, Hermosillo, Sonora (Mexico)
2013-02-01
We have developed a theory of one phonon resonant Raman scattering in a semiconductor quantum wire of cylindrical geometry in the presence of an external magnetic field distribution, parallel to the cylinder axis. The effect of the magnetic field in the electron and hole states, and in the Raman scattering efficiency, is determinate. We consider the electron-phonon interaction using a Froehlich-type Hamiltonian, deduced for the case of complete confinement phonon modes by Comas and his collaborators. We also assume T=0 K, a single parabolic conduction and valence bands. The spectra are discussed for different magnetic field values and the selection rules for the processes are also studied.
Effective potential and off-shell two-body scattering amplitudes in the eikonal approximation
Bartnik, E.A.; Rek, Z.
1973-12-31
An effective potential is computed for 2-body elastic scattering with the experimental on-shell t-matrices as an input. Nonrelativistic elkonal approximation and locality together with spherical ial are assumed. The explicit form of potential for pp, pi /sup +/p, and pi /sup -/p in the energy range from 5 to 20 GeV is investigated. The half off-shell scattering amplitude is calculated in the potential model. In the position representation this amplitude is found to be asymmetric along the eikonal direction, and an interesting absorption interpretation of this fact is given. (auth)
Temperature effects on multi-particle scattering in a gapped quantum magnet
Notbohm, S. [Hahn-Meitner-Institut, Glienicker Strasse 100, 14109 Berlin (Germany) and School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS (United Kingdom)]. E-mail: susanne.notbohm@hmi.de; Tennant, D.A. [Hahn-Meitner-Institut, Glienicker Strasse 100, 14109 Berlin (Germany); Institut fuer Festkoerperphysik, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Lake, B. [Hahn-Meitner-Institut, Glienicker Strasse 100, 14109 Berlin (Germany); Institut fuer Festkoerperphysik, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Canfield, P.C. [Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Fielden, J. [Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Koegerler, P. [Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Mikeska, H.-J. [Institut fuer Theoretische Physik, Universitaet Hannover, Appelstr. 2, 30167 Hannover (Germany); Luckmann, C. [Institut fuer Theoretische Physik, Universitaet Hannover, Appelstr. 2, 30167 Hannover (Germany); Telling, M.T.F. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 OQX (United Kingdom)
2007-03-15
We report measurements of the temperature effects on the dimerized antiferromagnetic chain material, copper nitrate Cu(NO{sub 3}){sub 2}.2.5D{sub 2}O. Using inelastic neutron scattering we have measured the temperature dependence of the one- and two-magnon excitation spectra as well as the temperature induced one-magnon intra-band scattering in a single crystal. Comparison is made with numerical evaluations of thermal averages based on the calculation for a chain of 16 spins.
Numerical Study of Coulomb Scattering Effects on Electron Beamfrom a Nano-Tip
Qiang, Ji; Corlett, John N.; Lidia, Steven M.; Padmore, HowardA.; Wan, Weishi; Zholent, Andrew A.; Zolotorev, Max
2007-06-25
Nano-tips with high acceleration gradient around the emission surface have been proposed to generate high brightness beams. However, due to the small size of the tip, the charge density near the tip is very high even for a small number of electrons. The stochastic Coulomb scattering near the tip can degrade the beam quality and cause extra emittance growth and energy spread. In the paper, we present a numerical study of these effects using a direct relativistic N-body model. We found that emittance growth and energy spread, due to Coulomb scattering, can be significantly enhanced with respect to mean-field space-charge calculations.
Medium effect in high density region probed by nucleus-nucleus elastic scattering
Furumoto, T; Yamamoto, Y
2014-01-01
We investigate the sensitivity of the medium effect in the high density region on the nucleus-nucleus elastic scattering in the framework of the double-folding (DF) model with the complex $G$-matrix interaction. First, the evaluating position of the local density, which is an ambiguity of the DF model, is investigated. However, the effect has a minor role to the nucleus-nucleus system. Next, the medium effect including three-body-force (TBF) effect is investigated with two methods. In the both methods, the medium effect is clearly seen on the potential and the elastic cross section, but not on the total reaction cross section. Finally, we make clear the crucial role of the TBF effect up to $k_F =$ 1.6 fm$^{-1}$ in the nucleus-nucleus elastic scattering.
Hammers, Martijn; Muskens, Gerard; Van Kats, Ruud J. M.; Teunissen, Wolf A.; Kleijn, David
2016-01-01
A key issue in conservation is where and how much management should be implemented to obtain optimal biodiversity benefits. Cost-effective conservation requires knowledge on whether biodiversity benefits are higher when management is concentrated in a few core areas or scattered across the
Effects of nonlinear phase modulation on Bragg scattering in the low-conversion regime
Andersen, Lasse Mejling; Cargill, D. S.; McKinstrie, C. J.
2012-01-01
In this paper, we consider the effects of nonlinear phase modulation on frequency conversion by four-wave mixing (Bragg scattering) in the low-conversion regime. We derive the Green functions for this process using the time-domain collision method, for partial collisions, in which the four fields...
Effects of nonlinear phase modulation on low-conversion four-wave mixing Bragg scattering
Andersen, Lasse Mejling; McKinstrie, C. J.; Rottwitt, Karsten
We consider the effects of nonlinear phase modulation (NPM) on frequency converseon by Bragg scattering. Previously we found that arbitrary mode reshaping without temporal entanglement (separability) was possible. When NPM is included, the modes are chirped and the separability is no longer compl...
Transverse spin effects in proton-proton scattering and $Q \\bar Q$ production
Goloskokov, S. V.
2002-01-01
We discuss transverse spin effects caused by the spin-flip part of the Pomeron coupling with the proton. The predicted spin asymmetries in proton-proton scattering and QQ production in proton-proton and lepton-proton reactions are not small and can be studied in future polarized experiments.
Preliminary study of rain effects on radar scattering from water surfaces
Moore, R. K.; Yu, Y. S.; Fung, A. K.; Dome, G. J.; Werp, R. E.; Kaneko, D.
1979-01-01
Preliminary wave-tank results indicate that radar scatter from water surfaces is severely affected by rain at low but not at high wind speeds. The effect is governed by both the rain rate and droplet size. A simple experiment to check this phenomenon is described.
Pilny, Lukas; Bissacco, Giuliano; De Chiffre, Leonardo
2014-01-01
Light scattering is a method for surface roughness measurements well suitable for use in a production environment thanks to its fast measurement rate, insensitivity to vibrations and to small misalignments. The method is however affected by several other factors. In this paper, the effect of angu...
Onyeaju, M. C.; Ikot, A. N.; Chukwuocha, E. O.; Obong, H. P.; Zare, S.; Hassanabadi, H.
2016-09-01
Scattering and bound states solution for the one-dimensional Klein-Gordon particle with Hylleraas potential is presented within the frame work of position dependent effective mass formalism. We calculate in detail the reflection and transmission coefficients using the properties of hypergeometric functions and the equation of continuity of the wave functions.
V. I. Egorov
2012-01-01
Full Text Available A scheme of a single photon source for quantum informatics applications based on the spontaneous parametric scattering effect is proposed and a quantum cryptography setup using it is presented. The system is compared to the alternative ones that operate with attenuated classic light.
Stark effect in Lax-Phillips scattering theory
Ben Ari, Tamar [Department of Physics, Bar Ilan University, Ramat Gan 52900 (Israel); Horwitz, L.P. [Department of Physics, Bar Ilan University, Ramat Gan 52900 (Israel) and School of Physics, Tel Aviv University, Ramat Aviv 69978 (Israel)]. E-mail: larry@post.tau.ac.il
2004-11-15
We show that for a simple version of the Stark effect, the Lax-Phillips eigenstate associated with the resonance can be explicitly computed, and we exhibit the (necessarily) semigroup property of decay in time. The widths and location of the resonances are those given by the poles of the resolvent of the standard quantum mechanical form.
Electron Gyro-Harmonic Effects on Ionospheric Stimulated Brillouin Scatter
2014-08-21
HAARP) facility. Increasing the maximum transmitter power up to 3.6 MW (effective radiated power ( ERP )∼1 GW) has allowed studying parametric decay...calculations are valid for SBS lines excited at the UH level and for the transmitted wave near vertical incidence. 3. Discussion and Conclusions
Bivariate Rayleigh Distribution and its Properties
Ahmad Saeed Akhter
2007-01-01
Full Text Available Rayleigh (1880 observed that the sea waves follow no law because of the complexities of the sea, but it has been seen that the probability distributions of wave heights, wave length, wave induce pitch, wave and heave motions of the ships follow the Rayleigh distribution. At present, several different quantities are in use for describing the state of the sea; for example, the mean height of the waves, the root mean square height, the height of the “significant waves” (the mean height of the highest one-third of all the waves the maximum height over a given interval of the time, and so on. At present, the ship building industry knows less than any other construction industry about the service conditions under which it must operate. Only small efforts have been made to establish the stresses and motions and to incorporate the result of such studies in to design. This is due to the complexity of the problem caused by the extensive variability of the sea and the corresponding response of the ships. Although the problem appears feasible, yet it is possible to predict service conditions for ships in an orderly and relatively simple manner Rayleigh (1980 derived it from the amplitude of sound resulting from many independent sources. This distribution is also connected with one or two dimensions and is sometimes referred to as “random walk” frequency distribution. The Rayleigh distribution can be derived from the bivariate normal distribution when the variate are independent and random with equal variances. We try to construct bivariate Rayleigh distribution with marginal Rayleigh distribution function and discuss its fundamental properties.
Transparent alumina: A light scattering model
Apetz, R.; Van Bruggen, P.B.
2003-01-01
A model based on Rayleigh-Gans-Debye light scattering theory has been developed to describe the light transmission properties of fine-grained, fully dense polycrystalline ceramics consisting of birefringent crystals. This model extends light transmission models based on geometrical optics, which are
Scattering and Diffraction of Electromagnetic Radiation: An Effective Probe to Material Structure
Xu, Yu-Lin
2016-01-01
scattered intensities are cross sections, such as for extinction, scattering, absorption, and radiation pressure, as a critical type of key quantity addressed in most theoretical and experimental studies of radiative scattering. Cross sections predicted from different scattering theories are supposed to be in general agreement. For objects of irregular shape, the GMM-PA solutions can be compared with the highly flexible Discrete Dipole Approximation (DDA) [4,5] when dividing a target to no more than 106 unit cells. Also, there are different ways to calculate the cross sections in the GMM-PA, providing an additional means to examine the accuracy of the numerical solutions and to unveil potential issues concerning the theoretical formulations and numerical aspects. To solve multiple scattering by an assembly of material volumes through classical theories such as the GMM-PA, the radiative properties of the component scatterers, the complex refractive index in particular, must be provided as input parameters. When using a PA to characterize a material body, this involves the use of an adequate theoretical tool, an effective medium theory, to connect Maxwell's phenomenogical theory with the atomistic theory of matter. In the atomic theory, one regards matter as composed of interacting particles (atoms and molecules) embedded in the vacuum [6]. However, the radiative properties of atomic-scaled particles are known to be substantially different from bulk materials. Intensive research efforts in the fields of cluster science and nanoscience attempt to bridge the gap between bulk and atom and to understand the transition from classical to quantum physics. The GMM-PA calculations, which place virtually no restriction on the component-particle size, might help to gain certain insight into the transition.
Effect of electron-phonon scattering anisotropy on the Hall effect in molybdenum
Cherepanov, V.I.; Startsev, V.E.; Volkenshtein, N.V.
1979-10-01
The Hall effect is studied in the temperature interval 2--150 K in monocrystalline molybdenum with resistance ratio rho/sub 273.2//rho/sub 4.2/ =32000. For T<80 /sup 0/K the Hall coefficient is anisotropic and has a nonmonotonic temperature dependence. An extremum in R/sub H/(T) is observed at hydrogen temperatures and is sensitive to the magnitude of the magnetic field. The observed behavior of R/sub H/(T) is explained by the Fermi surface geometry of molybdenum and by the influence of the electron-phonon scattering anisotropy. The interpretation of the experimental data is supported by a comparison of the temperature dependences of the Hall coefficient for molybdenum and tungsten.
Polarization effects in the non-linear Compton scattering
Ivanov, D Y; Serbo, V G
2005-01-01
We consider emission of a photon by an electron in the field of a strong laser wave. A probability of this process for circularly or linearly polarized laser photons and for arbitrary polarization of all other particles is calculated. We obtain the complete set of functions which describe such a probability in a compact invariant form. Besides, we discuss in some detail the polarization effects in the kinematics relevant to the problem of electron to photon conversion at photon-photon and electron-photon colliders.
Direct extraction of nuclear effects in quasielastic scattering on carbon
Wilkinson, Callum
2016-01-01
The differences between neutrino and antineutrino CCQE cross sections measured on hydrocarbon targets are due to fundamental differences in the cross section, different neutrino and antineutrino fluxes from the same beamline, and the additional interactions on hydrogen for antineutrinos that are absent for neutrinos. In this analysis we correct for the former two differences to extract a constraint on the ratio of the CCQE cross section for free and bound protons from MINERvA and MiniBooNE data. This measures nuclear effects in carbon, and we compare this measurement to models.