Exploiting Universality in Atoms with Large Scattering Lengths
Braaten, Eric
2012-05-31
The focus of this research project was atoms with scattering lengths that are large compared to the range of their interactions and which therefore exhibit universal behavior at sufficiently low energies. Recent dramatic advances in cooling atoms and in manipulating their scattering lengths have made this phenomenon of practical importance for controlling ultracold atoms and molecules. This research project was aimed at developing a systematically improvable method for calculating few-body observables for atoms with large scattering lengths starting from the universal results as a first approximation. Significant progress towards this goal was made during the five years of the project.
Kaonic hydrogen atom and kaon-proton scattering length
Y. Yan
2009-05-29
Kaonic hydrogen is studied with various realistic potentials in an accurate numerical approach based on Sturmian functions. The kaon-proton scattering length extracted from the 1s energy shift of the kaonic hydrogen by applying the Deser-Trueman formula is severely inconsistent with the one derived by directly solving the scattering Schoedinger equation. We pay special attention to the recent measurement of the energy shift and decay width of the 1s kaonic hydrogen state by the DEAR Collaboration. After taking into account the large discrepancy between the extracted and directly-evaluated scattering lengths, we found theoretical predictions of most chiral SU(3) based models for the kaonic hydrogen decay width are consistent with the DEAR data. We warn the SIDDHARTA collaboration that it may not be reasonable to extract kaon-nucleon scattering lengths, by using the Coulomb-interaction corrected Deser-Truemab formula, from the planned measurement of kaonic hydrogen.
Can one extract the pi-neutron scattering length from pi-deuteron scattering?
A. Nogga; C. Hanhart
2005-11-02
We give a prove of evidence that the original power counting by Weinberg can be applied to estimate the contributions of the operators contributing to the pi-deuteron scattering length. As a consequence, pi-deuteron observables can be used to extract neutron amplitudes--in case of pi-deuteron scattering this means that the pi-neutron scattering length can be extracted with high accuracy. This result is at variance with recent claims. We discuss the origin of this difference.
Universality in Few-body Systems with Large Scattering Length
Eric Braaten; H. -W. Hammer
2006-08-18
Particles with short-range interactions and a large scattering length have universal low-energy properties that do not depend on the details of their structure or their interactions at short distances. In the 2-body sector, the universal properties are familiar and depend only on the scattering length a. In the 3-body sector for identical bosons, the universal properties include the existence of a sequence of shallow 3-body bound states called "Efimov states" and log-periodic dependence of scattering observables on the energy and the scattering length. The spectrum of Efimov states in the limit a -> +/- infinity is characterized by an asymptotic discrete scaling symmetry that is the signature of renormalization group flow to a limit cycle. In this review, we present a thorough treatment of universality for the system of three identical bosons and we summarize the universal information that is currently available for other 3-body systems. Our basic tools are the hyperspherical formalism to provide qualitative insights, Efimov's radial laws for deriving the constraints from unitarity, and effective field theory for quantitative calculations. We also discuss topics on the frontiers of universality, including its extension to systems with four or more particles and the systematic calculation of deviations from universality.
Optical Scattering Lengths in Large Liquid-Scintillator Neutrino Detectors
Michael Wurm; Franz von Feilitzsch; Marianne Goeger-Neff; Martin Hofmann; Tobias Lachenmaier; Timo Lewke; Teresa Marrodan Undagoitita; Quirin Meindl; Randoplh Moellenberg; Lothar Oberauer; Walter Potzel; Marc Tippmann; Sebastian Todor; Christoph Traunsteiner; Juergen Winter
2010-04-06
For liquid-scintillator neutrino detectors of kiloton scale, the transparency of the organic solvent is of central importance. The present paper reports on laboratory measurements of the optical scattering lengths of the organic solvents PXE, LAB, and Dodecane which are under discussion for next-generation experiments like SNO+, Hanohano, or LENA. Results comprise the wavelength range from 415 to 440nm. The contributions from Rayleigh and Mie scattering as well as from absorption/re-emission processes are discussed. Based on the present results, LAB seems to be the preferred solvent for a large-volume detector.
The Dilute Bose-Einstein Condensate with Large Scattering Length
Eric Braaten; H. -W. Hammer; Thomas Mehen
2002-02-01
We study a dilute Bose gas of atoms whose scattering length a is large compared to the range of their interaction. We calculate the energy density of the homogeneous Bose-Einstein condensate to second order in the low-density expansion, expressing it in terms of a and a second parameter Lambda_* that determines the low-energy observables in the 3-body sector. The second-order correction to the energy density has a small imaginary part that reflects the instability due to 3-body recombination. In the case of a trapped Bose-Einstein condensate with large negative scattering length, we calculate the coefficient of the 3-body mean-field term in the energy density in terms of a and Lambda_*. It can be very large if there is an Efimov state near threshold.
Lambda-Neutron Scattering Lengths from Radiative K-minus Capture
W. R. Gibbs; S. A. Coon; H. K. Han; B. F. Gibson
2000-01-02
Radiative capture of the K-minus by the deuteron as a reaction for measurement of the Lambda-neutron scattering lengths. The use of spin information to separate the singlet and triplet scattering lengths is treated.
I=2 $?$-$?$ scattering length with dynamical overlap fermion
Takuya Yagi; Shoji Hashimoto; Osamu Morimatsu; Munehisa Ohtani
2011-08-15
We report on a lattice QCD calculation of the I=2 $\\pi\\pi$ scattering length using the overlap fermion formulation for both sea and valence quarks. We investigate the consistency of the lattice data with the prediction of the next-to-next-to-leading order chiral perturbation theory after correcting finite volume effects. The calculation is performed on gauge ensembles of two-flavor QCD generated by the JLQCD collaboration on a $16^3\\times 32$ lattice at a lattice spacing $\\sim$ 0.12 fm.
eta-Nucleon Scattering Length and Effective Range uncertainties
A. M. Green; S. Wycech
2005-06-28
The coupled eta-N, pi-N, gamma-N, 2pi-N system is described by a K-matrix method. The parameters in this model are adjusted to get an optimal fit to pi-N-->pi-N, pi-N-->eta-N, gamma-N-->pi-N and gamma-N-->eta-N data in an energy range of about 100 MeV or so each side of the eta-threshold. Compared with our earlier analysis, we now utilize recent Crystal Ball data. However, the outcome confirms our previous result that the eta-nucleon scattering length (a) is large with a value of 0.91(6)+i0.27(2) fm.
SPIN-DEPENDENT SCATTERING LENGTHS OF SLOW NEUTRONS WITH NUCLEI BY PSEUDOMAGNETIC MEASUREMENTS
Boyer, Edmond
L-263 SPIN-DEPENDENT SCATTERING LENGTHS OF SLOW NEUTRONS WITH NUCLEI BY PSEUDOMAGNETIC MEASUREMENTS vu par les noyaux. Abstract. - The spin-dependent scattering length of slow neutrons by the nuclei 23 can be of practical importance in many thermal neutron scattering experiments. A new method, called
Precision calculation of threshold pi^- d scattering, pi N scattering lengths, and the GMO sum rule
V. Baru; C. Hanhart; M. Hoferichter; B. Kubis; A. Nogga; D. R. Phillips
2011-10-14
We use chiral perturbation theory (ChPT) to calculate the $\\pi^- d$ scattering length with an accuracy of a few percent, including isospin-violating corrections both in the two- and three-body sector. In particular, we provide the technical details of a recent letter, where we used data on pionic deuterium and pionic hydrogen atoms to extract the isoscalar and isovector pion-nucleon scattering lengths $a^+$ and $a^-$. We study isospin-breaking contributions to the three-body part of $a_{\\pi^-d}$ due to mass differences, isospin violation in the $\\pi N$ scattering lengths, and virtual photons. This last class of effects is ostensibly infrared enhanced due to the smallness of the deuteron binding energy. However, we show that the leading virtual-photon effects that might undergo such enhancement cancel, and hence the standard ChPT counting provides a reliable estimate of isospin violation in $a_{\\pi^- d}$ due to virtual photons. Finally, we discuss the validity of the Goldberger-Miyazawa-Oehme sum rule in the presence of isospin violation, and use it to determine the charged-pion-nucleon coupling constant.
Precision calculation of threshold pi^- d scattering, pi N scattering lengths, and the GMO sum rule
Baru, V; Hoferichter, M; Kubis, B; Nogga, A; Phillips, D R
2011-01-01
We use chiral perturbation theory (ChPT) to calculate the $\\pi^- d$ scattering length with an accuracy of a few percent, including isospin-violating corrections both in the two- and three-body sector. In particular, we provide the technical details of a recent letter, where we used data on pionic deuterium and pionic hydrogen atoms to extract the isoscalar and isovector pion-nucleon scattering lengths $a^+$ and $a^-$. We study isospin-breaking contributions to the three-body part of $a_{\\pi^-d}$ due to mass differences, isospin violation in the $\\pi N$ scattering lengths, and virtual photons. This last class of effects is ostensibly infrared enhanced due to the smallness of the deuteron binding energy. However, we show that the leading virtual-photon effects that might undergo such enhancement cancel, and hence the standard ChPT counting provides a reliable estimate of isospin violation in $a_{\\pi^- d}$ due to virtual photons. Finally, we discuss the validity of the Goldberger-Miyazawa-Oehme sum rule in the p...
Three-Body Recombination of {sup 6}Li Atoms with Large Negative Scattering Lengths
Braaten, Eric; Kang, Daekyoung; Platter, Lucas; Hammer, H.-W.
2009-08-14
The three-body recombination rate at threshold for distinguishable atoms with large negative pair scattering lengths is calculated in the zero-range approximation. The only parameters in this limit are the 3 scattering lengths and the Efimov parameter, which can be complex-valued. We provide semianalytic expressions for the cases of 2 or 3 equal scattering lengths, and we obtain numerical results for the general case of 3 different scattering lengths. Our general result is applied to the three lowest hyperfine states of {sup 6}Li atoms. Comparisons with recent experiments provide indications of loss features associated with Efimov trimers near the 3-atom threshold.
Three-body Recombination of Lithium-6 Atoms with Large Negative Scattering Lengths
Eric Braaten; H. -W. Hammer; Daekyoung Kang; Lucas Platter
2009-10-29
The 3-body recombination rate at threshold for distinguishable atoms with large negative pair scattering lengths is calculated in the zero-range approximation. The only parameters in this limit are the 3 scattering lengths and the Efimov parameter, which can be complex valued. We provide semi-analytic expressions for the cases of 2 or 3 equal scattering lengths and we obtain numerical results for the general case of 3 different scattering lengths. Our general result is applied to the three lowest hyperfine states of Lithium-6 atoms. Comparisons with recent experiments provide indications of loss features associated with Efimov trimers near the 3-atom threshold.
Scattering lengths and medium and high energy {pi}{pi} scattering
Ananthanarayan, B.; Buettiker, P.
1996-11-01
Crucial tests of chiral perturbation theory and determinations of chiral coupling constants rely on fine details of dispersion relation analysis of {pi}{pi} scattering data. Whereas a recent Roy equation analysis of low energy {ital S} and {ital P} waves with {ital a}{sup 0}{sub 0} in the range predicted by standard one-loop chiral perturbation theory, yielded sharp determinations of certain {ital S}- and {ital P}-wave threshold parameters only, we now extend the discussion to medium and high energy. This is shown to contribute to the {ital D}-wave scattering lengths {ital a}{sup 0}{sub 2} and {ital a}{sup 2}{sub 2} significantly, roughly 10{percent} and 30{percent} of their central experimental values, remaining consistent with chiral predictions. Results of our Roy equation fits to the {ital F}-wave scattering length {ital a}{sup 1}{sub 3}, a quantity for which two-loop chiral perturbation theory holds important predictions, are presented. {copyright} {ital 1996 The American Physical Society.}
Resonant dimer relaxation in cold atoms with a large scattering length
Braaten, Eric; Hammer, H.-W.
2007-05-15
Efimov physics refers to universal phenomena associated with a discrete scaling symmetry in the three-body problem with a large scattering length. The first experimental evidence for Efimov physics was the recent observation of a resonant peak in the three-body recombination rate for {sup 133}Cs atoms with large negative scattering length. There can also be resonant peaks in the atom-dimer relaxation rate for large positive scattering length. We calculate the atom-dimer relaxation rate as a function of temperature and show how measurements of the relaxation rate can be used to determine accurately the parameters that govern Efimov physics.
Resonant Dimer Relaxation in Cold Atoms with a Large Scattering Length
Eric Braaten; H. -W. Hammer
2009-03-13
Efimov physics refers to universal phenomena associated with a discrete scaling symmetry in the 3-body problem with a large scattering length. The first experimental evidence for Efimov physics was the recent observation of a resonant peak in the 3-body recombination rate for 133Cs atoms with large negative scattering length. There can also be resonant peaks in the atom-dimer relaxation rate for large positive scattering length. We calculate the atom-dimer relaxation rate as a function of temperature and show how measurements of the relaxation rate can be used to determine accurately the parameters that govern Efimov physics.
Fresnel zone effects in the scattering of sound by cylinders of various lengths
Stanton, Tim
Fresnel zone effects in the scattering of sound by cylinders of various lengths DanielT. Di-source/point-receivercombination.Numerically evaluatingthisexpressionshowedthescatteringcharacteristicstobedominatedbyFresnel zoneeffects·scillationsin thebackscatterversuslengthcurvecausedbyconstructiveand
Determination of pi-N scattering lengths from pionic hydrogen and pionic deuterium data
A. Deloff
2001-04-23
The pi-N s-wave scattering lengths have been inferred from a joint analysis of the pionic hydrogen and the pionic deuterium x-ray data using a non-relativistic approach in which the pi-N interaction is simulated by a short-ranged potential. The pi-d scattering length has been calculated exactly by solving the Faddeev equations and also by using a static approximation. It has been shown that the same very accurate static formula for pi-d scattering length can be derived (i) from a set of boundary conditions; (ii) by a reduction of Faddeev equations; and (iii) through a summation of Feynman diagrams. By imposing the requirement that the pi-d scattering length, resulting from Faddeev-type calculation, be in agreement with pionic deuterium data, we obtain bounds on the pi-N scattering lengths. The dominant source of uncertainty on the deduced values of the pi-N scattering lengths are the experimental errors in the pionic hydrogen data.
Precision Measurement of the n-3He Incoherent Scattering Length Using Neutron Interferometry
M. G. Huber; M. Arif; T. C. Black; W. C. Chen; T. R. Gentile; D. S. Hussey; D. Pushin; F. E. Wietfeldt; L. Yang
2009-05-12
We report the first measurement of the low-energy neutron-$^3$He incoherent scattering length using neutron interferometry: $b_i' = (-2.512\\pm 0.012{statistical}\\pm0.014{systematic})$ fm. This is in good agreement with a recent calculation using the AV18+3N potential. The neutron-$^3$He scattering lengths are important for testing and developing nuclear potential models that include three nucleon forces, effective field theories for few-body nuclear systems, and neutron scattering measurements of quantum excitations in liquid helium. This work demonstrates the first use of a polarized nuclear target in a neutron interferometer.
Sarjonen, R.; Saarela, M.; Mazzanti, F.
2011-10-15
We present a theoretical analysis of excitation modes in Bose-Einstein condensates of ultracold alkali-metal gases for large scattering lengths, showing clear deviations from the Bogoliubov prediction as seen by Papp et al.[Phys. Rev. Lett. 101, 135301 (2008)]. We construct the atom-atom interaction by deriving the T matrix of such systems from two coupled (open and closed) channels assuming that the Feshbach resonance dominates the latter. We calculate molecular bound-state energies as a function of the magnetic field and compare with available experiments. The s-wave phase shifts determine the local effective interaction with long-ranged repulsion and short-ranged attraction. We show that it becomes a universal function at large scattering lengths. Finally, we use this interaction to characterize the ground-state and elementary excitations of {sup 85}Rb, {sup 87}Rb, and {sup 23}Na gases. Good agreement with line shift experiments in {sup 85}Rb is achieved. We find that, at large scattering lengths, Bragg scattering experiments could directly measure the momentum dependence of the effective two-body potential.
Eric Braaten; H. -W. Hammer; Daekyoung Kang; Lucas Platter
2008-11-14
For identical bosons with a large scattering length, the dependence of the 3-body recombination rate on the collision energy is determined in the zero-range limit by universal functions of a single scaling variable. There are six scaling functions for angular momentum zero and one scaling function for each higher partial wave. We calculate these universal functions by solving the Skorniakov--Ter-Martirosian equation. The results for the 3-body recombination as a function of the collision energy are in good agreement with previous results from solving the 3-body Schroedinger equation for 4He atoms. The universal scaling functions can be used to calculate the 3-body recombination rate at nonzero temperature. We obtain an excellent fit to the data from the Innsbruck group for 133Cs atoms with a large positive scattering length.
Three-body Recombination in Bose Gases with Large Scattering Length
Bedaque, P. F.; Braaten, Eric; Hammer, H.-W.
2000-07-31
An effective field theory for the three-body system with large scattering length is applied to three-body recombination to a weakly bound s -wave state in a Bose gas. Our model independent analysis demonstrates that the three-body recombination constant {alpha} is not universal, but can take any value between zero and 67.9({Dirac_h}/2{pi})a{sup 4}/m , where a is the scattering length. Other low-energy three-body observables can be predicted in terms of a and {alpha} . Near a Feshbach resonance, {alpha} should oscillate between those limits as the magnetic field B approaches the point where a{yields}{infinity} . In any interval of B over which a increases by a factor of 22.7, {alpha} should have a zero. (c) 2000 The American Physical Society.
Solution of A Class of Finite-Range Potentials with Large Scattering Length
Bimalendu Deb
2015-06-22
We show that there exists a class of finite-range model potentials that may be useful for describing resonant interactions with large scattering length at low energy. They are expressed in terms of the effective range $r_0$ and the $s$-wave scattering length $a_s$. The mathematical expression of the potential $V_+(r)$ with positive $a_s$ is different from that of the potential $V_{-}(r)$ with negative $a_s$. However, both reduce to the same form $V_{\\infty}$ in the unitarity limits $a_s \\rightarrow \\pm \\infty$. We derive scattering and bound-sate solutions of these potentials. By writing $V_{\\pm}(r) = V^{{\\rm PT}}(r) + V_{\\pm}^{\\epsilon}(r)$, where $ V^{{\\rm PT}}(r)$ is of the form of P\\"{o}schl-Teller potential and $V_{\\pm}^{\\epsilon}$ is expressed as a power series of the small parameter $\\epsilon = (\\sqrt{1 - 2 r_0/a_s})^{-1} - 1 $ when $a_s$ is large, we derive Green function of $V^{{\\rm PT}}(r)$ and thereby develop a perturbative method to obtain scattering solution of $V_{\\pm}(r)$ as a power series in $\\epsilon$. We describe the threshold behavior of scattering phase shift $\\delta_0$ in the unitarity limits and establish the connection of $\\delta_0$ with the strength of the P\\"{o}schl-Teller potential. This study may be important for developing an accurate description or better understanding of physics of strongly interacting ultracold atomic gases with tunable interactions.
Three-body recombination into deep bound states in a Bose gas with large scattering length
Eric Braaten; H. -W. Hammer
2001-06-04
An effective field theory for the three-body system with large scattering length a is applied to three-body recombination into deep bound states in a Bose gas. The recombination constant \\alpha is calculated to first order in the short-distance interactions that allow the recombination. For a < 0, the dimensionless combination m \\alpha/(\\hbar a^4) is a periodic function of \\ln |a| that exhibits resonances at values of a that differ by multiplicative factors of 22.7. This dramatic behavior should be observable near a Feshbach resonance when a becomes large and negative.
Three-Body Recombination into Deep Bound States in a Bose Gas with Large Scattering Length
Braaten, Eric; Hammer, H.-W.
2001-10-15
An effective field theory for the three-body system with large two-body scattering length a is applied to three-body recombination into deep bound states in a Bose gas. The recombination constant {alpha} is calculated to first order in the short-distance interactions that allow the recombination. For a<0 , the dimensionless combination m{alpha}/({Dirac_h}a{sup 4}) is a periodic function of ln
Uncertainties in the eta-Nucleon Scattering Length and Effective Range
A. M. Green; S. Wycech
2000-09-20
The coupled eta-N, pi-N, gamma-N system is described by a K-matrix method. The parameters in this model are adjusted to get an optimal fit to pi-N --->pi- N$, pi-N --->eta-N$, gamma-N--->pi-N and gamma-N --->eta-N data in an energy range of about 100MeV or so each side of the eta threshold. The outcome is the appearance of two solutions one which has an eta-nucleon scattering length (a) of about 1.0 fm and a second with a~0.2fm. However, the second solution has an unconventional non-Lorentian form for the T-matrix in the region of the 1535(20)MeV and 1650(30)MeV S-wave pi-N resonances.
Review of Indirect Methods Used to Determine the $^1S_0$ Neutron-Neutron Scattering Length
C. R. Howell
2008-05-08
We have determined a value for the $^1S_0$ neutron-neutron scattering length ($a_{nn}$) from high-precision measurements of time-of-flight spectra of neutrons from the $^2H(\\pi^-,n \\gamma)n$ capture reaction. The measurements were done at the Los Alamos Meson Physics Facility by the E1286 collaboration. The high spatial resolution of our gamma-ray detector enabled us to make a detailed assessment of the systematic uncertainties in our techniques. The value obtained in the present work is $a_{nn} = -18$.63 $\\pm $0.10 (statistical) $\\pm$ 0.44 (systematic) $\\pm$ 0.30 (theoretical) fm. This result is consistent with previous determinations of $a_{nn}$ from the $\\pi^-d$ capture reaction. We found that the analysis of the data with calculations that use a relativistic phase-space factor gives a more negative value for $a_{nn}$ by 0.33 fm over the analysis done using a nonrelativistic phase-space factor. Combining the present result with the previous ones from $\\pi^-d$ capture gives: $a_{nn} = - 18$.63 $\\pm$ 0.27 (expt) $\\pm$ 0.30 fm (theory). For the first time the combined statistical and systematic experimental uncertainty in $a_{nn}$ is smaller than the theoretical uncertainty and comparable to the uncertainty in the proton-proton $^1S_0$ scattering length ($a_{pp}$). This average value of $a_{nn}$ when corrected for the magnetic-moment interaction of the two neutrons becomes -18.9 $\\pm$ 0.4 fm which is 1.6 $\\pm$ 0.5 fm different from the recommended value of $a_{pp}$, thereby confirming charge symmetry breaking at the 1% confidence level.
Danon, Yaron
Scattering of 64 eV to 3 keV Neutrons from Polyethylene and Graphite and the Coherence Length 12180, USA (Received 31 August 2005; published 8 February 2006) We measured the neutron scattering by the neutron coherence length. The scattered intensity ratios were found to conform to conventional
Reeder, D. Benjamin (Davis Benjamin), 1966-
2002-01-01
This thesis investigates the complexities of acoustic scattering by finite bodies in general and by fish in particular through the development of an advanced acoustic scattering model and detailed laboratory acoustic ...
M. G. Huber; M. Arif; W. C. Chen; T. R. Gentile; D. S. Hussey; T. C. Black; D. A. Pushin; C. B. Shahi; F. E. Wietfeldt; L. Yang
2014-09-30
We report a determination of the n-$^3$He scattering length difference $\\Delta b^{\\prime} = b_{1}^{\\prime}-b_{0}^{\\prime} = $ ($-5.411$ $\\pm$ $0.031$ (statistical) $\\pm$ $0.039$ (systematic)) fm between the triplet and singlet states using a neutron interferometer. This revises our previous result $\\Delta b^{\\prime} = $ (-5.610 $\\pm$ $0.027$ (statistical) $\\pm$ $0.032$ (systematic) fm obtained using the same technique in 2008. This revision is due to a re-analysis of the 2008 experiment that includes a more robust treatment of the phase shift caused by magnetic field gradients near the $^3$He cell. Furthermore, we more than doubled our original data set from 2008 by acquiring six months of additional data in 2013. Both the new data set and a re-analysis of the older data are in good agreement. Scattering lengths of low Z isotopes are valued for use in few-body nuclear effective field theories, provide important tests of modern nuclear potential models and in the case of $^3$He aid in the interpretation of neutron scattering from quantum liquids. The difference $\\Delta b^{\\prime}$ was determined by measuring the relative phase shift between two incident neutron polarizations caused by the spin-dependent interaction with a polarized $^3$He target. The target $^3$He gas was sealed inside a small, flat windowed glass cell that was placed in one beam path of the interferometer. The relaxation of $^3$He polarization was monitored continuously with neutron transmission measurements. The neutron polarization and spin flipper efficiency were determined separately using $^3$He analyzers and two different polarimetry analysis methods. A summary of the measured scattering lengths for n-$^3$He with a comparison to nucleon interaction models is given.
Hadron-Hadron Interactions from $N_f=2+1+1$ Lattice QCD: isospin-2 $??$ scattering length
C. Helmes; C. Jost; B. Knippschild; C. Liu; J. Liu; L. Liu; C. Urbach; M. Ueding; Z. Wang; M. Werner
2015-06-01
We present results for the $I=2$ $\\pi\\pi$ scattering length using $N_f=2+1+1$ twisted mass lattice QCD for three values of the lattice spacing and a range of pion mass values. Due to the use of Laplacian Heaviside smearing our statistical errors are reduced compared to previous lattice studies. A detailed investigation of systematic effects such as discretisation effects, volume effects, and pollution of excited and thermal states is performed. After extrapolation to the physical point using chiral perturbation theory at NLO we obtain $M_\\pi a_0=-0.0442(2)_\\mathrm{stat}(^{+4}_{-0})_\\mathrm{sys}$.
MacDonald, Mark
2015-01-01
lengths for the flux of energy carried by thermal excitations, and for the net energy flux resulting from: 10.1103/PhysRevB.91.134507 PACS number(s): 67.30.em, 67.30.hb, 67.30.he I. INTRODUCTION In the zero, respectively, the mass of a Cooper pair and a bare 3 He atom. In the zero temperature limit, where the presence
A. B. Popov; T. Yu. Tretyakova
2008-12-30
We discuss the experimental data on the n,e-scattering length bne and the values of mean square charge radius of the neutron obtained from them. It is shown that the accumulated during the last 50 years most significant experimental estimates of the bne are not contradictory and lead to the average value =-0.1178+-0.0037 fm^2. Assuming that all the authors have underestimated the errors of their measurements by a factor of 1.7, the combined fit of all available experimental data would lead to Chi^2~1 per degree of freedom. Different modern theoretical predictions of are considered. They are found to be in a good agreement with the obtained experimental value . However the existing theoretical description of the structure of neutron does not provide a value of with a sufficient accuracy.
Hadron-Hadron Interactions from $N_f=2+1+1$ Lattice QCD: isospin-2 $\\pi\\pi$ scattering length
Helmes, C; Knippschild, B; Liu, C; Liu, J; Liu, L; Urbach, C; Ueding, M; Wang, Z; Werner, M
2015-01-01
We present results for the $I=2$ $\\pi\\pi$ scattering length using $N_f=2+1+1$ twisted mass lattice QCD for three values of the lattice spacing and a range of pion mass values. Due to the use of Laplacian Heaviside smearing our statistical errors are reduced compared to previous lattice studies. A detailed investigation of systematic effects such as discretisation effects, volume effects, and pollution of excited and thermal states is performed. After extrapolation to the physical point using chiral perturbation theory at NLO we obtain $M_\\pi a_0=-0.0442(2)_\\mathrm{stat}(^{+4}_{-0})_\\mathrm{sys}$.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque| Stanford Synchrotron Radiation LightsourceScattering Print
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque| Stanford Synchrotron Radiation LightsourceScattering
Small Angle Neutron Scattering Study of Conformation of Oligo(ethylene glycol)- Grafted Polystyrene Fengjun Hua,2 Kunlun Hong,2 and Jimmy W. Mays2 1Neutron Scattering Sciences Division, ORNL 2Center
Canonical quantum potential scattering theory
M. S. Hussein; W. Li; S. Wuester
2008-07-13
A new formulation of potential scattering in quantum mechanics is developed using a close structural analogy between partial waves and the classical dynamics of many non-interacting fields. Using a canonical formalism we find non-linear first-order differential equations for the low energy scattering parameters like scattering length and effective range. They significantly simplify typical calculations, as we illustrate for atom-atom and neutron-nucleus scattering systems. A generalization to charged particle scattering is also possible.
V. P. Levashev
2008-12-22
We have studied the relations between the neutron-triton scattering lengths and effective ranges and the corresponding quantities for the p --$^{3}$He scattering in the framework of the potential model with an effective nucleon-nucleus interaction in the form of a $\\delta $-shell potential. It is shown that the Coulomb renormalization of the pure nuclear scattering lengths does not change the relation well established for the n + $^{3}$H system between the lengths: $A^{1} scattering lengths which give preference to set I of the phase analysis performed by E.A. George et al. (2003), which corresponds to the inequality $A^{1}_{nc} scattering lengths.
Sprouse, Gene D. [American Physical Society (United States)
2011-07-15
Technological changes have moved publishing to electronic-first publication where the print version has been relegated to simply another display mode. Distribution in HTML and EPUB formats, for example, changes the reading environment and reduces the need for strict pagination. Therefore, in an effort to streamline the calculation of length, the APS journals will no longer use the printed page as the determining factor for length. Instead the journals will now use word counts (or word equivalents for tables, figures, and equations) to establish length; for details please see http://publish.aps.org/authors/length-guide. The title, byline, abstract, acknowledgment, and references will not be included in these counts allowing authors the freedom to appropriately credit coworkers, funding sources, and the previous literature, bringing all relevant references to the attention of readers. This new method for determining length will be easier for authors to calculate in advance, and lead to fewer length-associated revisions in proof, yet still retain the quality of concise communication that is a virtue of short papers.
X-ray and Neutron Scattering Studies of Magnetic Domain Dynamics and Spin Structures /
Chen, San-Wen
2014-01-01
Stanley. X-ray and neutron scattering from rough surfaces.1988. [3] R. Pynn. Neutron scattering by rough surfaces at39] V. F. Sears. Neutron scattering lengths and cross
Sandia Energy - Scattering Dynamics
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Scattering Dynamics Home Transportation Energy Predictive Simulation of Engines Combustion Chemistry Chemical Dynamics Scattering Dynamics Scattering DynamicsAshley...
Alexandru C Mihul; Eleonora A Mihul
2006-08-25
Lorentz ordering (causality) implies the following rule: for any given energy p0 of a system there is a certain interval c0 on x0 so that their product is the Lorentz ordering constant L It means p0c0 = L. The constant L=hc. Hence Planck constant h in a similar way as c are both consequences of Lorentz metric. The basic ideas are: 1. Lorentz metric implies that x0 must represent a length like the other components of x in X 2. The dual metric space X* is well defined since the Lorentz metric tensor is not singular. The components of the vectors p in X*are interpreted as representing energy. The properties of the physical systems that are direct consequences of the detailed structure of X and X*, and so expressed through the Lorentz Limit L are presented.
Branch length distribution in TREF fractionated polyethylene Ramnath Ramachandran a
Beaucage, Gregory
Branch length distribution in TREF fractionated polyethylene Ramnath Ramachandran a , Gregory Keywords: Polyethylene Branching Neutron scattering a b s t r a c t Commercial polyethylene is typically and catalyst activity. Further, processing of polyethylene after polymerization may also result in changes
Spin-dependent scattering and absorption of thermal neutrons on dynamically polarized nuclei
Paris-Sud XI, Université de
957 Spin-dependent scattering and absorption of thermal neutrons on dynamically polarized nuclei H neutrons and polarized nuclei have been used to measure spin-dependent scattering lengths and absorption cross sections of slow (S-wave) neutrons on nuclei. In order to obtain those scattering lengths
Comparing Membrane Simulations to Scattering Experiments: Introducing the SIMtoEXP Software
Nagle, John F.
of biomembrane simulations with experimental X-ray and neutron scattering data. It has the following features: (1 the electron density e(z) and neutron scattering length density m(z) profiles along the z direction (i.e., nor simulation Á X-ray scattering Á Neutron scattering Á Computer software Introduction It is well recognized
MAGNETIC NEUTRON SCATTERING. And Recent Developments in the Triple Axis Spectroscopy
Johnson, Peter D.
Chapter 1 MAGNETIC NEUTRON SCATTERING. And Recent Developments in the Triple Axis Spectroscopy Igor.................................................................................... 2 2. Neutron interaction with matter and scattering cross-section ........ 6 2.1 Basic scattering theory and differential cross-section................ 7 2.2 Neutron interactions and scattering lengths
Formation lengths of hadrons in lepto-production
Levon Grigoryan
2012-09-28
The average formation lengths of the hadrons produced during the deep inelastic scattering (DIS) of leptons on protons are studied in the framework of the symmetric Lund model. It is shown that these formation lengths essentially depend on the electric charges of the hadron. For electro-production and charged current (CC) neutrino-production, the average formation lengths of positively charged particles are larger than those of negatively charged antiparticles. This situation is reversed for CC antineutrino-production. In all the mentioned cases, the main mechanism is the direct production of hadrons. The additional mechanism of hadron production, through the decay of resonances, is essential only for pions and leads to a decrease in the average formation lengths.
Intravalley Multiple Scattering of Quasiparticles in Graphene
J. Y. Vaishnav; Justin Q. Anderson; Jamie D. Walls
2011-05-28
We develop a theoretical description of intravalley scattering of quasiparticles in graphene from multiple short-range scatterers of size much greater than the carbon-carbon bond length. Our theory provides a method to rapidly calculate the Green's function in graphene for arbitrary configurations of scatterers. We demonstrate that non-collinear multiple scattering trajectories generate pseudospin rotations that alter quasiparticle interference, resulting in significant modifications to the shape, intensity, and pattern of the interference fringes in the local density of states (LDOS). We illustrate these effects via theoretical calculations of the LDOS for a variety of scattering configurations in single layer graphene. A clear understanding of impurity scattering in graphene is a step towards exploiting graphene's unique properties to build future devices.
Zero energy scattering calculation in Euclidean space
Carbonell, J
2016-01-01
We show that the Bethe-Salpeter equation for the scattering amplitude in the limit of zero incident energy can be transformed into a purely Euclidean form, as it is the case for the bound states. The decoupling between Euclidean and Minkowski amplitudes is only possible for zero energy scattering observables and allows determining the scattering length from the Euclidean Bethe-Salpeter amplitude. Such a possibility strongly simplifies the numerical solution of the Bethe-Salpeter equation and suggests an alternative way to compute the scattering length in Lattice Euclidean calculations without using the Luscher formalism. The derivations contained in this work were performed for scalar particles and one-boson exchange kernel. They can be generalized to the fermion case and more involved interactions.
Three-body Recombination in Bose Gases with Large Scattering...
Office of Scientific and Technical Information (OSTI)
with large scattering length is applied to three-body recombination to a weakly bound s -wave state in a Bose gas. Our model independent analysis demonstrates that the three-body...
Progress in Long Scale Length Laser-Plasma Interactions
Glenzer, S H; Arnold, P; Bardsley, G; Berger, R L; Bonanno, G; Borger, T; Bower, D E; Bowers, M; Bryant, R; Buckman, S; Burkhart, S C; Campbell, K; Chrisp, M P; Cohen, B I; Constantin, G; Cooper, F; Cox, J; Dewald, E; Divol, L; Dixit, S; Duncan, J; Eder, D; Edwards, J; Erbert, G; Felker, B; Fornes, J; Frieders, G; Froula, D H; Gardner, S D; Gates, C; Gonzalez, M; Grace, S; Gregori, G; Greenwood, A; Griffith, R; Hall, T; Hammel, B A; Haynam, C; Heestand, G; Henesian, M; Hermes, G; Hinkel, D; Holder, J; Holdner, F; Holtmeier, G; Hsing, W; Huber, S; James, T; Johnson, S; Jones, O S; Kalantar, D; Kamperschroer, J H; Kauffman, R; Kelleher, T; Knight, J; Kirkwood, R K; Kruer, W L; Labiak, W; Landen, O L; Langdon, A B; Langer, S; Latray, D; Lee, A; Lee, F D; Lund, D; MacGowan, B; Marshall, S; McBride, J; McCarville, T; McGrew, L; Mackinnon, A J; Mahavandi, S; Manes, K; Marshall, C; Mertens, E; Meezan, N; Miller, G; Montelongo, S; Moody, J D; Moses, E; Munro, D; Murray, J; Neumann, J; Newton, M; Ng, E; Niemann, C; Nikitin, A; Opsahl, P; Padilla, E; Parham, T; Parrish, G; Petty, C; Polk, M; Powell, C; Reinbachs, I; Rekow, V; Rinnert, R; Riordan, B; Rhodes, M
2003-11-11
The first experiments on the National Ignition Facility (NIF) have employed the first four beams to measure propagation and laser backscattering losses in large ignition-size plasmas. Gas-filled targets between 2 mm and 7 mm length have been heated from one side by overlapping the focal spots of the four beams from one quad operated at 351 nm (3{omega}) with a total intensity of 2 x 10{sup 15} W cm{sup -2}. The targets were filled with 1 atm of CO{sub 2} producing of up to 7 mm long homogeneously heated plasmas with densities of n{sub e} = 6 x 10{sup 20} cm{sup -3} and temperatures of T{sub e} = 2 keV. The high energy in a NIF quad of beams of 16kJ, illuminating the target from one direction, creates unique conditions for the study of laser plasma interactions at scale lengths not previously accessible. The propagation through the large-scale plasma was measured with a gated x-ray imager that was filtered for 3.5 keV x rays. These data indicate that the beams interact with the full length of this ignition-scale plasma during the last {approx}1 ns of the experiment. During that time, the full aperture measurements of the stimulated Brillouin scattering and stimulated Raman scattering show scattering into the four focusing lenses of 6% for the smallest length ({approx}2 mm). increasing to 12% for {approx}7 mm. These results demonstrate the NIF experimental capabilities and further provide a benchmark for three-dimensional modeling of the laser-plasma interactions at ignition-size scale lengths.
Scattering Solar Thermal Concentrators
Giebink, Noel C.
2015-01-31
This program set out to explore a scattering-based approach to concentrate sunlight with the aim of improving collector field reliability and of eliminating wind loading and gross mechanical movement through the use of a stationary collection optic. The approach is based on scattering sunlight from the focal point of a fixed collection optic into the confined modes of a sliding planar waveguide, where it is transported to stationary tubular heat transfer elements located at the edges. Optical design for the first stage of solar concentration, which entails focusing sunlight within a plane over a wide range of incidence angles (>120 degree full field of view) at fixed tilt, led to the development of a new, folded-path collection optic that dramatically out-performs the current state-of-the-art in scattering concentration. Rigorous optical simulation and experimental testing of this collection optic have validated its performance. In the course of this work, we also identified an opportunity for concentrating photovoltaics involving the use of high efficiency microcells made in collaboration with partners at the University of Illinois. This opportunity exploited the same collection optic design as used for the scattering solar thermal concentrator and was therefore pursued in parallel. This system was experimentally demonstrated to achieve >200x optical concentration with >70% optical efficiency over a full day by tracking with <1 cm of lateral movement at fixed latitude tilt. The entire scattering concentrator waveguide optical system has been simulated, tested, and assembled at small scale to verify ray tracing models. These models were subsequently used to predict the full system optical performance at larger, deployment scale ranging up to >1 meter aperture width. Simulations at an aperture widths less than approximately 0.5 m with geometric gains ~100x predict an overall optical efficiency in the range 60-70% for angles up to 50 degrees from normal. However, the concentrator optical efficiency was found to decrease significantly with increasing aperture width beyond 0.5 m due to parasitic waveguide out-coupling loss and low-level absorption that become dominant at larger scale. A heat transfer model was subsequently implemented to predict collector fluid heat gain and outlet temperature as a function of flow rate using the optical model as a flux input. It was found that the aperture width size limitation imposed by the optical efficiency characteristics of the waveguide limits the absolute optical power delivered to the heat transfer element per unit length. As compared to state-of-the-art parabolic trough CPV system aperture widths approaching 5 m, this limitation leads to an approximate factor of order of magnitude increase in heat transfer tube length to achieve the same heat transfer fluid outlet temperature. The conclusion of this work is that scattering solar thermal concentration cannot be implemented at the scale and efficiency required to compete with the performance of current parabolic trough CSP systems. Applied within the alternate context of CPV, however, the results of this work have likely opened up a transformative new path that enables quasi-static, high efficiency CPV to be implemented on rooftops in the form factor of traditional fixed-panel photovoltaics.
Continuously variable focal length lens
Adams, Bernhard W; Chollet, Matthieu C
2013-12-17
A material preferably in crystal form having a low atomic number such as beryllium (Z=4) provides for the focusing of x-rays in a continuously variable manner. The material is provided with plural spaced curvilinear, optically matched slots and/or recesses through which an x-ray beam is directed. The focal length of the material may be decreased or increased by increasing or decreasing, respectively, the number of slots (or recesses) through which the x-ray beam is directed, while fine tuning of the focal length is accomplished by rotation of the material so as to change the path length of the x-ray beam through the aligned cylindrical slows. X-ray analysis of a fixed point in a solid material may be performed by scanning the energy of the x-ray beam while rotating the material to maintain the beam's focal point at a fixed point in the specimen undergoing analysis.
Screening length in plasma winds
Elena Caceres; Makoto Natsuume; Takashi Okamura
2007-06-04
We study the screening length L_s of a heavy quark-antiquark pair in strongly coupled gauge theory plasmas flowing at velocity v. Using the AdS/CFT correspondence we investigate, analytically, the screening length in the ultra-relativistic limit. We develop a procedure that allows us to find the scaling exponent for a large class of backgrounds. We find that for conformal theories the screening length is (boosted energy density)^{-1/d}. As examples of conformal backgrounds we study R-charged black holes and Schwarzschild-anti-deSitter black holes in (d+1)-dimensions. For non-conformal theories, we find that the exponent deviates from -1/d and as examples we study the non-extremal Klebanov-Tseytlin and Dp-brane geometries. We find an interesting relation between the deviation of the scaling exponent from the conformal value and the speed of sound.
[49] INTERSUBUNIT MEASUREMENTS BY NEUTRON SCATTERING 629 ribosomal 30 S subparticle in its lateral Neutron Scattering By PETER B. MOOREand DONALDM. ENGELMAN Several years ago we suggested that neutron.28 " The scattering lengths are taken from G. E. Bacon, "Neutron Scattering." Oxford Univ. Press (Clarendon
Variable focal length deformable mirror
Headley, Daniel (Albuquerque, NM); Ramsey, Marc (Albuquerque, NM); Schwarz, Jens (Albuquerque, NM)
2007-06-12
A variable focal length deformable mirror has an inner ring and an outer ring that simply support and push axially on opposite sides of a mirror plate. The resulting variable clamping force deforms the mirror plate to provide a parabolic mirror shape. The rings are parallel planar sections of a single paraboloid and can provide an on-axis focus, if the rings are circular, or an off-axis focus, if the rings are elliptical. The focal length of the deformable mirror can be varied by changing the variable clamping force. The deformable mirror can generally be used in any application requiring the focusing or defocusing of light, including with both coherent and incoherent light sources.
Distributions of off-diagonal scattering matrix elements: Exact results
Nock, A. Kumar, S. Sommers, H.-J. Guhr, T.
2014-03-15
Scattering is a ubiquitous phenomenon which is observed in a variety of physical systems which span a wide range of length scales. The scattering matrix is the key quantity which provides a complete description of the scattering process. The universal features of scattering in chaotic systems is most generally modeled by the Heidelberg approach which introduces stochasticity to the scattering matrix at the level of the Hamiltonian describing the scattering center. The statistics of the scattering matrix is obtained by averaging over the ensemble of random Hamiltonians of appropriate symmetry. We derive exact results for the distributions of the real and imaginary parts of the off-diagonal scattering matrix elements applicable to orthogonally-invariant and unitarily-invariant Hamiltonians, thereby solving a long standing problem. -- Highlights: •Scattering problem in complex or chaotic systems. •Heidelberg approach to model the chaotic nature of the scattering center. •A novel route to the nonlinear sigma model based on the characteristic function. •Exact results for the distributions of off-diagonal scattering-matrix elements. •Universal aspects of the scattering-matrix fluctuations.
Satat, Guy
2015-01-01
In this thesis we demonstrate novel methods to overcome optical scattering in order to resolve information about hidden scenes, in particular for biomedical applications. Imaging through scattering media has long been a ...
Word lengths are optimized for efficient communication
Makous, Walter
Word lengths are optimized for efficient communication Steven T. Piantadosi1 , Harry Tily celebrated empirical laws in the study of language, Zipf's 75-y-old theory that word length is primarily languages that average information content is a much better predictor of word length than frequency
dynamics that occur in the ®nal stages of protein folding, we have used neutron scattering to probe- lastic neutron scattering (IQNS). The IQNS results show length scale dependent, pico-second dynamics neutron scattering; a-lactalbumin*Corresponding author Introduction Proteins can form collapsed, partially
High-Energy Scattering vs Static QCD Strings
V. A. Petrov; R. A. Ryutin
2014-09-30
We discuss the shape of the interaction region of the elastically scattered protons stipulated by the high-energy Pomeron exchange which turns out to be very similar with the shape of the static string representing the confining QCD flux tube. This similarity disappears when we enter the LHC energy region, which corresponds to many-Pomeron exchanges. Reversing the argument we conjecture a modified relationship between the width and the length of the confining string at very large lengths.
Scattering of low-energy electrons and positrons by atomic beryllium: Ramsauer-Townsend effect
Reid, David D
2014-01-01
Total cross sections for the scattering of low-energy electrons and positrons by atomic beryllium in the energy range below the first inelastic thresholds are calculated. A Ramsauer-Townsend minimum is seen in the electron scattering cross sections, while no such effect is found in the case of positron scattering. A minimum total cross section of 0.016 a.u. at 0.0029 eV is observed for the electron case. In the limit of zero energy, the cross sections yield a scattering length of -0.61 a.u. for electron and +13.8 a.u. for positron scattering.
E. Borie
2013-02-05
A recent proposal to measure the proton form factor by means of muon-proton scattering will use muons which are not ultrarelativistic (and also not nonrelativistic). The usual equations describing the scattering cross section use the approximation that the scattered lepton (usually an electron) is ultrarelativistic, with v/c approximately equal to 1. Here the cross section is calculated for all values of the energy. It agrees with the standard result in the appropriate limit.
Environment scattering in GADRAS.
Thoreson, Gregory G.; Mitchell, Dean James; Theisen, Lisa Anne; Harding, Lee T.
2013-09-01
Radiation transport calculations were performed to compute the angular tallies for scattered gamma-rays as a function of distance, height, and environment. Green's Functions were then used to encapsulate the results a reusable transformation function. The calculations represent the transport of photons throughout scattering surfaces that surround sources and detectors, such as the ground and walls. Utilization of these calculations in GADRAS (Gamma Detector Response and Analysis Software) enables accurate computation of environmental scattering for a variety of environments and source configurations. This capability, which agrees well with numerous experimental benchmark measurements, is now deployed with GADRAS Version 18.2 as the basis for the computation of scattered radiation.
Scattering Techniques and Geometries
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
grains - Thin films - Texture (crystallite orientation) - Real time experiments (electrochemistry, stress-strain) Get to know your beamlines incident scattered Detector Q...
Lujan Neutron Scattering Center
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
the inadvertent spread of Technetium 99 by employees and contractors at the Lujan Neutron Scattering Center August 27, 2012-The Laboratory is investigating the inadvertent...
Temperature dependence of diffusion length, lifetime and minority electron mobility in GaInP
Schultes, F. J.; Haegel, N. M.; Christian, T.; Alberi, K.; Fluegel, B.; Jones-Albertus, R.; Pickett, E.; Liu, T.; Misra, P.; Sukiasyan, A.; Yuen, H.
2013-12-09
The mobility of electrons in double heterostructures of p-type Ga{sub 0.50}In{sub 0.50}P has been determined by measuring minority carrier diffusion length and lifetime. The minority electron mobility increases monotonically from 300?K to 5?K, limited primarily by optical phonon and alloy scattering. Comparison to majority electron mobility over the same temperature range in comparably doped samples shows a significant reduction in ionized impurity scattering at lower temperatures, due to differences in interaction of repulsive versus attractive carriers with ionized dopant sites. These results should be useful in modeling and optimization for multi-junction solar cells and other optoelectronic devices.
The Fiber Optic Multiplexed Upgraded Thomson Scattering Diagnostic for the ISTTOK Tokamak
The Fiber Optic Multiplexed Upgraded Thomson Scattering Diagnostic for the ISTTOK Tokamak M. P by different length optical fibers used to relay the scattered light to a single spectrometer. 2. Thomson vessel and opposite to the collection lenses. Figure 1 shows the present two fiber optic Thomson
Low energy scattering phase shifts for meson-baryon systems
Detmold, William
2015-01-01
In this work, we calculate meson-baryon scattering phase shifts in four channels using lattice QCD methods. From a set of calculations at four volumes, corresponding to spatial sizes of 2, 2.5, 3, and 4 fm, and a pion mass of m_pi ~ 390 MeV, we determine the scattering lengths and effective ranges for these systems at the corresponding quark masses. We also perform the calculation at a lighter quark mass, m_pi ~ 230 MeV, on the largest volume. Using these determinations, along with those in previous work, we perform a chiral extrapolation of the scattering lengths to the physical point after correcting for the effective range contributions using the multi-volume calculations performed at m_pi ~ 390 MeV.
Probing the Conformational Distributions of Sub-Persistence Length DNA
Mastroianni, Alexander; Sivak, David; Geissler, Phillip; Alivisatos, Paul
2009-06-08
We have measured the bending elasticity of short double-stranded DNA (dsDNA) chains through small-angle X-ray scattering from solutions of dsDNA-linked dimers of gold nanoparticles. This method, which does not require exertion of external forces or binding to a substrate, reports on the equilibrium distribution of bending fluctuations, not just an average value (as in ensemble FRET) or an extreme value (as in cyclization), and in principle provides a more robust data set for assessing the suitability of theoretical models. Our experimental results for dsDNA comprising 42-94 basepairs (bp) are consistent with a simple worm-like chain model of dsDNA elasticity, whose behavior we have determined from Monte Carlo simulations that explicitly represent nanoparticles and their alkane tethers. A persistence length of 50 nm (150 bp) gave a favorable comparison, consistent with the results of single-molecule force-extension experiments on much longer dsDNA chains, but in contrast to recent suggestions of enhanced flexibility at these length scales.
Positron scattering and annihilation from the hydrogen molecule at zero energy
Zhang, J -Y; Varga, K
2009-01-01
The confined variational method is used to generate a basis of correlated gaussians to describe the interaction region wave function for positron scattering from the H$_2$ molecule. The scattering length was $\\approx -2.7$ $a_0$ while the zero energy $Z_{\\rm eff}$ of 15.7 is compatible with experimental values. The variation of the scattering length and $Z_{\\rm eff}$ with inter-nuclear distance was surprisingly rapid due to virtual state formation at $R \\approx 3.4$ $a_0$.
A length operator for canonical quantum gravity
T. Thiemann
1996-06-29
We construct an operator that measures the length of a curve in four-dimensional Lorentzian vacuum quantum gravity. We work in a representation in which a $SU(2)$ connection is diagonal and it is therefore surprising that the operator obtained after regularization is densely defined, does not suffer from factor ordering singularities and does not require any renormalization. We show that the length operator admits self-adjoint extensions and compute part of its spectrum which like its companions, the volume and area operators already constructed in the literature, is purely discrete and roughly is quantized in units of the Planck length. The length operator contains full and direct information about all the components of the metric tensor which faciliates the construction of a new type of weave states which approximate a given classical 3-geometry.
Mixing lengths scaling in a gravity flow
Ecke, Robert E [Los Alamos National Laboratory; Rivera, Micheal [Los Alamos National Laboratory; Chen, Jun [Los Alamos National Laboratory; Ecke, Robert E [Los Alamos National Laboratory
2009-01-01
We present an experimental study of the mixing processes in a gravity current. The turbulent transport of momentum and buoyancy can be described in a very direct and compact form by a Prandtl mixing length model [1]: the turbulent vertical fluxes of momentum and buoyancy are found to scale quadraticatly with the vertical mean gradients of velocity and density. The scaling coefficient is the square of the mixing length, approximately constant over the mixing zone of the stratified shear layer. We show in this paper how, in different flow configurations, this length can be related to the shear length of the flow {radical}({var_epsilon}/{partial_derivative}{sub z}u{sup 3}).
Word lengths are optimized for efficient communication
Piantadosi, Steven Thomas
We demonstrate a substantial improvement on one of the most celebrated empirical laws in the study of language, Zipf's 75-y-old theory that word length is primarily determined by frequency of use. In accord with rational ...
Recent Developments in Few-Nucleon Scattering
A. Kievsky
2010-02-05
Using modern nucleon-nucleon interactions in the description of the $A=3,4$ nuclei, it is not possible to reproduce both the three- and four-nucleon binding energies simultaneously. This is one manifestation of the necessity of including a three-nucleon force in the nuclear Hamiltonian. Several models of the three-nucleon force exist and are applied in the description of light nuclei. However, as it is discussed here, a simultaneous description of the three- and four-body binding energies and the $n-d$ doublet scattering length seems to be problematic. Accordingly, a comparative study of some of these models is performed. In a different analysis, we study applications of the Kohn Variational Principle, formulated in terms of integral relations, to describe $N-d$ scattering processes.
Process for fabricating continuous lengths of superconductor
Kroeger, Donald M. (Knoxville, TN); List, III, Frederick A. (Andersonville, TN)
1998-01-01
A process for manufacturing a superconductor. The process is accomplished by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon, overlaying a continuous length of a second substrate ribbon on said first substrate ribbon, and applying sufficient pressure to form a bound layered superconductor precursor between said first substrate ribbon and said second substrates ribbon. The layered superconductor precursor is then heat treated to form a super conductor layer.
Scattering Solar Thermal Concentrators
Broader source: Energy.gov [DOE]
"This fact sheet describes a scattering solar thermal concentrators project awarded under the DOE's 2012 SunShot Concentrating Solar Power R&D award program. The team, led by the Pennsylvania State University, is working to demonstrate a new, scattering-based approach to concentrating sunlight that aims to improve the overall performance and reliability of the collector field. The research team aims to show that scattering solar thermal collectors are capable of achieving optical performance equal to state-of-the-art parabolic trough systems, but with the added benefits of immunity to wind-load tracking error, more efficient land use, and utilization of stationary receivers."
quantum scattering calculations
Ihee, Hyotcherl
in a given quantum state per solid angle unit cross section : integral of the differential cross section) converged integral and differential cross sections geometriquantum scattering calculations on chemical reaction 1st Day #12;schedule day 1. 1.Introduction day
Polarized Proton Nucleus Scattering
B. Z. Kopeliovich; T. L. Trueman
2001-05-28
We show that, to a very good approximation, the ratio of the spin-flip to the non-flip parts of the elastic proton-nucleus amplitude is the same as for proton-nucleon scattering at very high energy. The result is used to do a realistic calculation of the analyzing power A_N for pC scattering in the Coulomb-nuclear interference (CNI) region of momentum transfer.
Imaging an event horizon: mitigation of scattering toward Sagittarius A*
Fish, Vincent L.; Lu, Ru-Sen; Doeleman, Sheperd S.; Pankratius, Victor [Massachusetts Institute of Technology, Haystack Observatory, Route 40, Westford, MA 01886 (United States); Johnson, Michael D.; Narayan, Ramesh; Vertatschitsch, Laura E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bouman, Katherine L.; Zoran, Daniel; Freeman, William T. [Massachusetts Institute of Technology, Computer Science and Artificial Intelligence Laboratory, 32 Vassar Street, Cambridge, MA 02139 (United States); Psaltis, Dimitrios [Astronomy and Physics Departments, University of Arizona, 933 North Cherry Street, Tucson, AZ 85721 (United States); Broderick, Avery E. [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, ON N2L 2Y5 (Canada); Gwinn, Carl R., E-mail: vfish@haystack.mit.edu [Department of Physics, University of California, Santa Barbara, CA 93106 (United States)
2014-11-10
The image of the emission surrounding the black hole in the center of the Milky Way is predicted to exhibit the imprint of general relativistic (GR) effects, including the existence of a shadow feature and a photon ring of diameter ?50 ?as. Structure on these scales can be resolved by millimeter-wavelength very long baseline interferometry. However, strong-field GR features of interest will be blurred at ? ? 1.3 mm due to scattering by interstellar electrons. The scattering properties are well understood over most of the relevant range of baseline lengths, suggesting that the scattering may be (mostly) invertible. We simulate observations of a model image of Sgr A* and demonstrate that the effects of scattering can indeed be mitigated by correcting the visibilities before reconstructing the image. This technique is also applicable to Sgr A* at longer wavelengths.
March, 2001 Neutron Scattering Group
Johnson, Peter D.
March, 2001 Neutron Scattering Group A High Performance Hybrid Spectrometer for theA High of the instrument performance · Igor Zaliznyak · Laurence Passell OutlineOutline #12;Neutron Scattering GroupNeutron states in single crystals.single crystals. #12;Neutron Scattering GroupNeutron Scattering Group What
Fracture Properties From Seismic Scattering
Burns, Daniel R.
2007-01-01
Fractures scatter seismic energy and this energy can be analyzed to provide information about fracture
S-wave scattering lengths and effective ranges for collisions of ground state Be atoms
Jamieson, M.J.
Jamieson,M.J. Cheung,A.S.C. Ouerdane,H. Jeung,G.H. Geum,N. Journal of Physics B, Volume 40 pp 3497-3504
Stimulated forward Raman scattering in large scale-length laser-produced
Office of Scientific and Technical Information (OSTI)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)Feedback System inStatus of the MEIC ion colliderArticle) |andplasmas
Stimulated forward Raman scattering in large scale-length laser-produced
Office of Scientific and Technical Information (OSTI)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)Feedback System inStatus of the MEIC ion colliderArticle)
Three-body Recombination in Bose Gases with Large Scattering Length
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory of rare Kaon and Pion decaysArticle) | SciTechworkSciTech
Sighting optics including an optical element having a first focal length and a second focal length
Crandall, David Lynn (Idaho Falls, ID)
2011-08-01
One embodiment of sighting optics according to the teachings provided herein may include a front sight and a rear sight positioned in spaced-apart relation. The rear sight includes an optical element having a first focal length and a second focal length. The first focal length is selected so that it is about equal to a distance separating the optical element and the front sight and the second focal length is selected so that it is about equal to a target distance. The optical element thus brings into simultaneous focus, for a user, images of the front sight and the target.
Crystal diffraction lens with variable focal length
Smither, Robert K. (Hinsdale, IL)
1991-01-01
A method and apparatus for altering the focal length of a focusing element o one of a plurality of pre-determined focal lengths by changing heat transfer within selected portions of the element by controlled quantities. Control over heat transfer is accomplished by manipulating one or more of a number of variables, including: the amount of heat or cold applied to surfaces; type of fluids pumped through channels for heating and cooling; temperatures, directions of flow and rates of flow of fluids; and placement of channels.
Apparatus for fabricating continuous lengths of superconductor
Kroeger, Donald M. (Knoxville, TN); List, III, Frederick A. (Andersonville, TN)
2002-01-01
A process and apparatus for manufacturing a superconductor. The process is accomplished by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon, overlaying a continuous length of a second substrate ribbon on said first substrate ribbon, and applying sufficient pressure to form a bound layered superconductor comprising a layer of said superconducting precursor powder between said first substrate ribbon and said second substrates ribbon. The layered superconductor is then heat treated to establish the superconducting phase of said superconductor precursor powder.
Apparatus for fabricating continuous lengths of superconductor
Kroeger, Donald M. (Knoxville, TN); List, III, Frederick A. (Andersonville, TN)
2001-01-01
A process and apparatus for manufacturing a superconductor. The process is accomplished by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon, overlaying a continuous length of a second substrate ribbon on said first substrate ribbon, and applying sufficient pressure to form a bound layered superconductor comprising a layer of said superconducting precursor powder between said first substrate ribbon and said second substrates ribbon. The layered superconductor is then heat treated to establish the superconducting phase of said superconductor precursor powder.
Crystal diffraction lens with variable focal length
Smither, R.K.
1991-04-02
A method and apparatus for altering the focal length of a focusing element of one of a plurality of pre-determined focal lengths by changing heat transfer within selected portions of the element by controlled quantities is disclosed. Control over heat transfer is accomplished by manipulating one or more of a number of variables, including: the amount of heat or cold applied to surfaces; type of fluids pumped through channels for heating and cooling; temperatures, directions of flow and rates of flow of fluids; and placement of channels. 19 figures.
Naohiro Kanda
2011-06-03
For a long time, it is believed that the light by light scattering is described properly by the Lagrangian density obtained by Heisenberg and Euler. Here, we present a new calculation which is based on the modern field theory technique. It is found that the light-light scattering is completely different from the old expression. The reason is basically due to the unphysical condition (gauge condition) which was employed by the QED calcualtion of Karplus and Neumann. The correct cross section of light-light scattering at low energy of $(\\frac{\\omega}{m} \\ll 1)$ can be written as $ \\displaystyle{\\frac{d\\sigma}{d\\Omega}=\\frac{1}{(6\\pi)^2}\\frac{\\alpha^4} {(2\\omega)^2}(3+2\\cos^2\\theta +\\cos^4\\theta)}$.
Quaglioni, S; Navratil, P; Roth, R
2009-12-15
The exact treatment of nuclei starting from the constituent nucleons and the fundamental interactions among them has been a long-standing goal in nuclear physics. Above all nuclear scattering and reactions, which require the solution of the many-body quantum-mechanical problem in the continuum, represent an extraordinary theoretical as well as computational challenge for ab initio approaches.We present a new ab initio many-body approach which derives from the combination of the ab initio no-core shell model with the resonating-group method [4]. By complementing a microscopic cluster technique with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters, this approach is capable of describing simultaneously both bound and scattering states in light nuclei. We will discuss applications to neutron and proton scattering on sand light p-shell nuclei using realistic nucleon-nucleon potentials, and outline the progress toward the treatment of more complex reactions.
Length dependence of the Raman spectra of carbon nanotubes
Zare, Aurea Tucay
2009-01-01
DNA-wrapping technology, combined with size-exclusion chromatography, have made possible the sorting of carbon nanotubes according to length. In particular, length sorted nanotube samples, with finite lengths approaching ...
Length Scale of Leidenfrost Ratchet Switches Droplet Directionality...
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Small Angle Neutron Scattering
Urban, Volker S [ORNL
2012-01-01
Small Angle Neutron Scattering (SANS) probes structural details at the nanometer scale in a non-destructive way. This article gives an introduction to scientists who have no prior small-angle scattering knowledge, but who seek a technique that allows elucidating structural information in challenging situations that thwart approaches by other methods. SANS is applicable to a wide variety of materials including metals and alloys, ceramics, concrete, glasses, polymers, composites and biological materials. Isotope and magnetic interactions provide unique methods for labeling and contrast variation to highlight specific structural features of interest. In situ studies of a material s responses to temperature, pressure, shear, magnetic and electric fields, etc., are feasible as a result of the high penetrating power of neutrons. SANS provides statistical information on significant structural features averaged over the probed sample volume, and one can use SANS to quantify with high precision the structural details that are observed, for example, in electron microscopy. Neutron scattering is non-destructive; there is no need to cut specimens into thin sections, and neutrons penetrate deeply, providing information on the bulk material, free from surface effects. The basic principles of a SANS experiment are fairly simple, but the measurement, analysis and interpretation of small angle scattering data involves theoretical concepts that are unique to the technique and that are not widely known. This article includes a concise description of the basics, as well as practical know-how that is essential for a successful SANS experiment.
What Does a Scattering Pattern Tell US?
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Scattering Space sample light image Image Space lens Angular Space Q 4p sin(q) l Fourier Transform Scattering Pattern Fourier Transform Phase Problem Scattering Pattern...
Neutron Scattering Tutorials | Neutron Science | ORNL
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Neutron Scattering Tutorials SHARE Neutron Scattering Tutorials The following lectures were presented at the 2011 and 2010 National School on Neutron & X-Ray Scattering. This...
New hydrocracking catalysts increase throughput, run length
Huizinga, T. [Shell Internationale Petroleum Mij., The Hague (Netherlands); Theunissen, J.M.H. [Rayong Refinery Co. Ltd., Rayong (Thailand); Minderhoud, H.; Veen, R. van [Koninklijke/Shell-Lab., Amsterdam (Netherlands)
1995-06-26
An improved, second-stage hydrocracking catalyst has been developed by combining stabilized Y zeolites with amorphous silica alumina cracking components. A commercial application of this catalyst, along with a new, first-stage zeolitic hydrocracking catalyst, resulted in increased unit throughput and cycle length. The paper discusses the hydrocracking process, first-stage catalysts, second-stage catalysts, hydrogenation process, commercial results, and product properties.
Critical length limiting super-low friction
Ming Ma; Andrea Benassi; Andrea Vanossi; Michael Urbakh
2015-01-02
Since the demonstration of super-low friction (superlubricity) in graphite at nanoscale, one of the main challenges in the field of nano- and micro-mechanics was to scale this phenomenon up. A key question to be addressed is to what extent superlubricity could persist, and what mechanisms could lead to its failure. Here, using an edge-driven Frenkel-Kontorova model, we establish a connection between the critical length above which superlubricity disappears and both intrinsic material properties and experimental parameters. A striking boost in dissipated energy with chain length emerges abruptly due to a high-friction stick-slip mechanism caused by deformation of the slider leading to a local commensuration with the substrate lattice. We derived a parameter-free analytical model for the critical length that is in excellent agreement with our numerical simulations. Our results provide a new perspective on friction and nano-manipulation and can serve as a theoretical basis for designing nano-devices with super-low friction, such as carbon nanotubes.
Low-energy potential scattering in two and three dimensions
N. N. Khuri; Andre Martin; Jean-Marc Richard; Tai Tsun Wu
2009-06-10
Conditions are established for the existence of a scattering length and an effective range in the low-energy expansion of the S-wave phase-shift of a central potential in two and three dimensions. The behavior of the phase-shift as a function of the momentum is also derived for longer-range power-law potentials which do not fulfill these conditions.
Time-of-flight direct recoil ion scattering spectrometer
Krauss, A.R.; Gruen, D.M.; Lamich, G.J.
1994-09-13
A time-of-flight direct recoil and ion scattering spectrometer beam line is disclosed. The beam line includes an ion source which injects ions into pulse deflection regions and separated by a drift space. A final optics stage includes an ion lens and deflection plate assembly. The ion pulse length and pulse interval are determined by computerized adjustment of the timing between the voltage pulses applied to the pulsed deflection regions. 23 figs.
Length and Energy of Quadratic Bezier Curves and Applications
Hoffmann, Christoph M.
Length and Energy of Quadratic B´ezier Curves and Applications Young Joon Ahn a , Christoph for the arc length and the bending energy of quadratic B´ezier curves. The formulae are in terms control point is analyzed for curves of fixed arc length or bending energy. In the case of arc length
Small angle neutron scattering in materials science: Recent practical applications
Melnichenko, Yuri B [ORNL; Wignall, George D [ORNL
2007-01-01
Modern materials science and engineering relies increasingly on detailed knowledge of the structure and interactions in 'soft' and 'hard' materials, but there have been surprisingly few microscopic techniques for probing the structures of bulk samples of these substances. Small-angle neutron scattering (SANS) was first recognized in Europe as a major technique for this purpose and, over the past several decades, has been a growth area in both academic and industrial materials research to provide structural information on length scales {approx}10-1000 Angstroms (or 1-100 nm). The technique of ultrahigh resolution small-angle neutron scattering (USANS) raises the upper resolution limit for structural studies by more than two orders of magnitude and (up to {approx}30 {micro}m) and hence overlaps with light scattering and microscopy. This review illustrates the ongoing vitality of SANS and USANS in materials research via a range of current practical applications from both soft and hard matter nanostructured systems.
Vernon, M.F.
1983-07-01
The molecular-beam technique has been used in three different experimental arrangements to study a wide range of inter-atomic and molecular forces. Chapter 1 reports results of a low-energy (0.2 kcal/mole) elastic-scattering study of the He-Ar pair potential. The purpose of the study was to accurately characterize the shape of the potential in the well region, by scattering slow He atoms produced by expanding a mixture of He in N/sub 2/ from a cooled nozzle. Chapter 2 contains measurements of the vibrational predissociation spectra and product translational energy for clusters of water, benzene, and ammonia. The experiments show that most of the product energy remains in the internal molecular motions. Chapter 3 presents measurements of the reaction Na + HCl ..-->.. NaCl + H at collision energies of 5.38 and 19.4 kcal/mole. This is the first study to resolve both scattering angle and velocity for the reaction of a short lived (16 nsec) electronic excited state. Descriptions are given of computer programs written to analyze molecular-beam expansions to extract information characterizing their velocity distributions, and to calculate accurate laboratory elastic-scattering differential cross sections accounting for the finite apparatus resolution. Experimental results which attempted to determine the efficiency of optically pumping the Li(2/sup 2/P/sub 3/2/) and Na(3/sup 2/P/sub 3/2/) excited states are given. A simple three-level model for predicting the steady-state fraction of atoms in the excited state is included.
Transmission Eigenvalues in Inverse Scattering Theory
2012-04-22
TE and Scattering Theory. Spherically Stratified Media. Transmission Eigenvalues. Open Problem. Transmission Eigenvalues in Inverse. Scattering Theory.
s-wave scattering of a polarizable atom by an absorbing nanowire
Fink, Martin; Arnecke, Florian; Eiglsperger, Johannes; Friedrich, Harald; Madronero, Javier; Raab, Patrick; Naranjo, Andres; Wirzba, Andreas
2010-06-15
We study the scattering of a polarizable atom by a conducting cylindrical wire with incoming boundary conditions, that is, total absorption, near the surface of the wire. Based on the explicit expression given recently [C. Eberlein and R. Zietal, Phys. Rev. A 75, 032516 (2007)] for the nonretarded atom-wire potential, we formulate a hierarchy of approximations that enables the numerical determination of this potential to any desired accuracy as economically as possible. We calculate the complex s-wave scattering length for the effectively two-dimensional atom-wire scattering problem. The scattering length a depends on the radius R of the wire and a characteristic length {beta} related to the polarizability of the atom via a simple scaling relation, a=R a{approx}({beta}/R). The 'scaled scattering length' a{approx} tends to unity in the thick-wire limit {beta}/R{yields}0, and it grows almost proportional to 1/R in the opposite thin-wire limit.
Multiple Contributors
1988-01-01
Trek IV! SHALOM PAX PEACE to us all in 1986 Table of Contents TITLE AUTHOR ARTIST PAGE I. DATA ENTRIES FROST ON THE TYPEWRITER V.L. Thorn LaVena Kay Kldd 2 "Trek Omen" V.L. Thorn 6 (originally appeared In TREKisM #26) JAMES T. KIRK vs THE COMPUTER... appeared in TREKisM at Length III) TALES FROM THE VULCAN HEARTH Karen C. Hunter 53 HOW THE VULCANS LOST THEIR WINGS 54 THE SKY GOD'S DAUGHTER 56 THE GIFT OF THE GODS LaVena Kay Kldd 57 "Sul Generis" V.L. Thorn 58 "Cat-Kin" Emily Ross 60 (originally appeared...
Multiple Contributors
1983-01-01
Length III is published by the Star Trek Special Interest Group LSIGJ of Mensa. Copyright (c) 1983..., 1701 W. Third St, Brooklyn NY 11223. \\S In January Paramount STAR TREK new produc Star Trek' no time wa two-and-a- of TREKisM interested said in an Thank you, never ceas the contin eternally ixgmqp^ion of 19 P i c t u r II. A er, Ha...
Localization length of nearly periodic layered metamaterials
del Barco, O
2015-01-01
We have analyzed numerically the localization length of light $\\xi$ for nearly periodic arrangements of homogeneous stacks (formed exclusively by right-handed materials) and mixed stacks (with alternating right and left-handed metamaterials). Layers with index of refraction $n_1$ and thickness $L_1$ alternate with layers of index of refraction $n_2$ and thickness $L_2$. Positional disorder has been considered by shifting randomly the positions of the layer boundaries with respect to periodic values. For homogeneous stacks, we have shown that the localization length is modulated by the corresponding bands and that $\\xi$ is enhanced at the center of each allowed band. In the limit of long-wavelengths $\\lambda$, the parabolic behavior previously found in purely disordered systems is recovered, whereas for $\\lambda \\ll L_1 + L_2$ a saturation is reached. In the case of nearly periodic mixed stacks with the condition $|n_1 L_1|=|n_2 L_2|$, instead of bands there is a periodic arrangement of Lorenztian resonances, ...
Nanoscale structure in AgSbTe2 determined by diffuse elastic neutron scattering
Specht, Eliot D [ORNL; Ma, Jie [ORNL; Delaire, Olivier A [ORNL; Budai, John D [ORNL; May, Andrew F [ORNL; Karapetrova, Evguenia A. [Argonne National Laboratory (ANL)
2015-01-01
Diffuse elastic neutron scattering measurements confirm that AgSbTe2 has a hierarchical structure, with defects on length scales from nanometers to microns. While scattering from mesoscale structure is consistent with previously-proposed structures in which Ag and Sb order on a NaCl lattice, more diffuse scattering from nanoscale structure suggests a structural rearrangement in which hexagonal layers form a combination of (ABC), (ABA), and (AAB) stacking sequences. The AgCrSe2 structure is the best-fitting model for the local atomic arrangements.
A New Polyethylene Scattering Law Determined Using Inelastic Neutron Scattering
Lavelle, Christopher M [ORNL; Liu, C [Oak Ridge National Laboratory (ORNL); Stone, Matthew B [ORNL
2013-01-01
Monte Carlo neutron transport codes such as MCNP rely on accurate data for nuclear physics cross-sections to produce accurate results. At low energy, this takes the form of scattering laws based on the dynamic structure factor, S (Q, E). High density polyethylene (HDPE) is frequently employed as a neutron moderator at both high and low temperatures, however the only cross-sections available are for T =300 K, and the evaluation has not been updated in quite some time. In this paper we describe inelastic neutron scattering measurements on HDPE at 5 and 300 K which are used to improve the scattering law for HDPE. We describe the experimental methods, review some of the past HDPE scattering laws, and compare computations using these models to the measured S (Q, E). The total cross-section is compared to available data, and the treatment of the carbon secondary scatterer as a free gas is assessed. We also discuss the use of the measurement itself as a scattering law via the 1 phonon approximation. We show that a scattering law computed using a more detailed model for the Generalized Density of States (GDOS) compares more favorably to this experiment, suggesting that inelastic neutron scattering can play an important role in both the development and validation of new scattering laws for Monte Carlo work.
Chen, Wei-Ren [ORNL; Do, Changwoo [ORNL; Hong, Kunlun [ORNL; Liu, Emily [Rensselaer Polytechnic Institute (RPI); Liu, Yun [National Institute of Standards and Technology (NIST); Porcar, L. [National Institute of Standards and Technology (NIST); Smith, Gregory Scott [ORNL; Wu, Bin [ORNL; Egami, T [University of Tennessee, Knoxville (UTK); Smith, Sean C [ORNL
2012-01-01
Based on atomistic molecular dynamics (MD) simulations, the small angle neutron scattering (SANS) intensity behavior of a single generation-4 (G4) polyelectrolyte polyamidoamine (PAMAM) starburst dendrimer is investigated at different levels of molecular protonation. The SANS form factor, P(Q), and Debye autocorrelation function, (r), are calculated from the equilibrium MD trajectory based on a mathematical approach proposed in this work which provides a link between the neutron scattering experiment and MD computation. The simulations enable scattering calculations of not only the hydrocarbons, but also the contribution to the scattering length density fluctuations caused by structured, confined water within the dendrimer. Based on our computational results, we question the validity of using radius of gyration RG for microstructure characterization of a polyelectrolyte dendrimer from the scattering perspective.
Weak Deeply Virtual Compton Scattering
Ales Psaker; Wolodymyr Melnitchouk; Anatoly Radyushkin
2007-03-01
We extend the analysis of the deeply virtual Compton scattering process to the weak interaction sector in the generalized Bjorken limit. The virtual Compton scattering amplitudes for the weak neutral and charged currents are calculated at the leading twist within the framework of the nonlocal light-cone expansion via coordinate space QCD string operators. Using a simple model, we estimate cross sections for neutrino scattering off the nucleon, relevant for future high intensity neutrino beam facilities.
Fast Length-Constrained MAP Decoding of Variable Length Coded Markov Sequences over Noisy Channels
Wu, Xiaolin
Zhe Wang, Xiaolin Wu and Sorina Dumitrescu Department of Electrical and Computer Engineering McMaster University, Hamilton, Ontario, Canada L8S 4K1 zwang@grads.ece.mcmaster.ca xwu that is variable length coded and transmitted over a binary symmetric channel. The number of source symbols
INVERSE MEDIUM SCATTERING PROBLEMS FOR ...
SIAM (#1) 1035 2001 Apr 10 12:32:38
2005-08-08
An energy estimate for the scattered field with a uniform bound with respect to the ...... are not stored. We use the commonly used compressed row storage (CRS) ...
Advances in total scattering analysis
Proffen, Thomas E [Los Alamos National Laboratory; Kim, Hyunjeong [Los Alamos National Laboratory
2008-01-01
In recent years the analysis of the total scattering pattern has become an invaluable tool to study disordered crystalline and nanocrystalline materials. Traditional crystallographic structure determination is based on Bragg intensities and yields the long range average atomic structure. By including diffuse scattering into the analysis, the local and medium range atomic structure can be unravelled. Here we give an overview of recent experimental advances, using X-rays as well as neutron scattering as well as current trends in modelling of total scattering data.
Dictionaries Using Variable-Length Keys and Data, with Applications *
Blelloch, Guy E.
(Isil- logn, 1) + Itil) and Isil is the length of bit string si. We assume a word length w > log m. We present string Isil > 1, Itil > 1 for all bit-strings si and ti. Fox' fixed-length keys the dictionary problem
Generation of Full-Length cDNA Library
Chuong, Cheng-Ming
Generation of Full- Length cDNA Library from Single Human Prostate Cancer Cells BioTechniques 27 are performed on fixed and per- meabilized cells. Subsequent RT-PCR generates full-length cDNA libraries. Flowchart of current method for generating a full-length cDNA library from single cells. Cell fixation
Neutron Scattering Group February, 2001
Johnson, Peter D.
Neutron Scattering Group February, 2001 A High Performance Instrument for the Single Crystal Igor Zaliznyak Outline #12;Neutron Scattering Group Neutron spectrometer for studies of the low-energy coherent excitations in single crystals. Common requirements for a single crystal neutron spectrometer
A New Basis for Interpretation of the Planck Length
C. L. Herzenberg
2006-10-17
A critical length has recently been identified that appears to provide a fundamental limit distinguishing quantum behavior from classical behavior. Because of the unique association between critical length and mass, it appears that we can correlate the mass of an object with the size over which its quantum behavior is manifested. When the expression for the critical length is set equal to the Planck length, we find an associated mass value that in magnitude corresponds to an approximation of the mass of the visible universe. This would appear to suggest that the quantum behavior associated with the universe as a whole would be manifested at distances comparable to or smaller than the Planck length. Accordingly, it would appear that all position measurements would be subject to uncertainties at the limit of the Planck length, so that the Planck length sets a fundamental limit on position determination.
Hu, Naiping; Borkar, Neha; Kohls, Doug; Schaefer, Dale W. (UCIN)
2014-09-24
A combination of ultra small angle X-ray scattering (USAXS) and ultra small angle neutron scattering (USANS) is used to characterize porous materials. The analysis methods yield quantitative information, including the mean skeletal chord length, mean pore chord length, skeletal density, and composition. A mixed cellulose ester (MCE) membrane with a manufacturer-labeled pore size of 0.1 {mu}m was used as a model to elucidate the specifics of the method. Four approaches describing four specific scenarios (different known parameters and form of the scattering data) are compared. Pore chords determined using all four approaches are in good agreement with the scanning electron microscopy estimates but are larger than the manufacturer's nominal pore size. Our approach also gives the average chord of the skeletal solid (struts) of the membrane, which is also consistent for all four approaches. Combined data from USAXS and USANS gives the skeletal density and the strut composition.
Requirements, possible alternatives & international NEUTRON SCATTERING
Dimeo, Robert M.
Requirements, possible alternatives & international NEUTRON SCATTERING DETECTORS for Rob Dimeo NIST neutron scattering instruments are the most demanding require background low #12;#12;The Helium-3 Supply Crisis Alternative Techniques to Helium-3 based Detectors for Neutron Scattering Applications
LIGHT SCATTERING STUDIES OF SILICA AEROGELS
Hunt, A.J.
2010-01-01
van de Hulst, H.C. , Light Scattering by Small Particles,A New Polarization-Modulated Light Scattering Instrument,"and interpretation of light scattering effects in aerogels.
Search for: "neutron scattering" | DOE PAGES
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neutron scattering" Find + Advanced Search Advanced Search All Fields: "neutron scattering" Title: Full Text: Bibliographic Data: Creator Author: Name Name ORCID Search...
Microwave scattering from laser spark in air
Sawyer, Jordan; Zhang Zhili [Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Shneider, Mikhail N. [Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States)
2012-09-15
In this paper, microwave Mie scattering from a laser-induced plasma in atmospheric air is computed. It shows that the scattered microwave transitions from coherent Rayleigh scattering to Mie scattering based on the relative transparency of the laser-induced plasma at the microwave frequency. The microwave penetration in the plasma alters from total transparency to partial shielding due to the sharp increase of the electron number density within the avalanche ionization phase. The transition from Rayleigh scattering to Mie scattering is verified by both the temporal evolution of the scattered microwave and the homogeneity of polar scattering plots.
Neutron Scattering User Program | Neutron Science | ORNL
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User Program SHARE Neutron Scattering Can Benefit Your Research Neutron scattering has applications in almost every technical and scientific field, from biology and chemistry to...
11th LANSCE School on Neutron Scattering
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11th LANSCE School on Neutron Scattering LANSCE 11th LANSCE School on Neutron Scattering Home Abstract Lecturers Lecturer Abstracts Hands-On Experiments Free Day About the...
SciTech Connect: "neutron scattering"
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neutron scattering" Find + Advanced Search Term Search Semantic Search Advanced Search All Fields: "neutron scattering" Semantic Semantic Term Title: Full Text: Bibliographic...
Benchmark calculations for elastic fermion-dimer scattering
Shahin Bour; H. -W. Hammer; Dean Lee; Ulf-G. Meißner
2012-06-08
We present continuum and lattice calculations for elastic scattering between a fermion and a bound dimer in the shallow binding limit. For the continuum calculation we use the Skorniakov-Ter-Martirosian (STM) integral equation to determine the scattering length and effective range parameter to high precision. For the lattice calculation we use the finite-volume method of L\\"uscher. We take into account topological finite-volume corrections to the dimer binding energy which depend on the momentum of the dimer. After subtracting these effects, we find from the lattice calculation kappa a_fd = 1.174(9) and kappa r_fd = -0.029(13). These results agree well with the continuum values kappa a_fd = 1.17907(1) and kappa r_fd = -0.0383(3) obtained from the STM equation. We discuss applications to cold atomic Fermi gases, deuteron-neutron scattering in the spin-quartet channel, and lattice calculations of scattering for nuclei and hadronic molecules at finite volume.
A. Gashi; E. Matsinos; G. C. Oades; G. Rasche; W. S. Woolcock
2007-10-18
Using newly calculated electromagnetic corrections, we have made a phase shift analysis of experimental data on pi+/- p elastic scattering up to 100 MeV, assuming the effective hadronic interaction to be isospin invariant. The output consists of parametrised s and p-wave hadronic phases for isospin 1/2 and 3/2. It is not possible to fit the charge exchange data satisfactorily. We give values for the s-wave scattering lengths and effective ranges and for the p-wave scattering volumes. The combinations 2a_1 + a_3 and a_1 - a_3 of s-wave scattering lengths extracted from pionic hydrogen data are compared with those obtained from our analysis.
Thomson scattering diagnostic for the measurement of ion species fraction
Ross, J. S.; Park, H.-S.; Amendt, P.; Divol, L.; Kugland, N. L.; Glenzer, S. H. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Rozmus, W. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Department of Physics, University of Alberta Edmonton, Alberta T6G 2R3 (Canada)
2012-10-15
Simultaneous Thomson scattering measurements of collective electron-plasma and ion-acoustic fluctuations have been utilized to determine ion species fraction from laser produced CH plasmas. The CH{sub 2} foil is heated with 10 laser beams, 500 J per beam, at the Omega Laser facility. Thomson scattering measurements are made 4 mm from the foil surface using a 30 J 2{omega} probe laser with a 1 ns pulse length. Using a series of target shots the plasma evolution is measured from 2.5 ns to 9 ns after the rise of the heater beams. Measuring the electron density and temperature from the electron-plasma fluctuations constrains the fit of the two-ion species theoretical form factor for the ion feature such that the ion temperature, plasma flow velocity and ion species fraction are determined. The ion species fraction is determined to an accuracy of {+-}0.06 in species fraction.
K$^-$-proton scattering and the $?(1405)$ in dense matter
Volker Koch
1994-06-25
The scattering of antikaons with nucleons is studied in the nuclear environment. Describing the $\\lam$ as a $K^-$ proton bound state, we find, that due to the Pauli blocking of intermediate states, the mass of the $\\Lambda (1405)$ is shifted upwards in energy, above the $K^-$ proton threshold and and its width is somewhat broadened. As a consequence the s-wave $K^-$--nucleon scattering length turns attractive at finite nucleon density ($\\rho \\geq 0.25 \\rho_0$) leading to a mean field potential for the $K^-$ of about $\\sim -100 \\, \\rm MeV$ in nuclear matter at ground state density. Consequences for Heavy Ion collisions and possible experimental checks for the structure of the $\\lam$ are discussed. (Figures will be sent on request)
Pitch-angle scattering of energetic particles with adiabatic focusing
Tautz, R. C. [Zentrum für Astronomie und Astrophysik, Technische Universität Berlin, Hardenbergstraße 36, D-10623 Berlin (Germany); Shalchi, A. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Dosch, A., E-mail: robert.c.tautz@gmail.com, E-mail: andreasm4@yahoo.com, E-mail: alexanderm.dosch@gmail.com [Center for Space Plasmas and Aeronomic Research, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35805 (United States)
2014-10-20
Understanding turbulent transport of charged particles in magnetized plasmas often requires a model for the description of random variations in the particle's pitch angle. The Fokker-Planck coefficient of pitch-angle scattering, which is used to describe scattering parallel to the mean magnetic field, is therefore of central importance. Whereas quasi-linear theory assumes a homogeneous mean magnetic field, such a condition is often not fulfilled, especially for high-energy particles. Here, a new derivation of the quasi-linear approach is given that is based on the unperturbed orbit found for an adiabatically focused mean magnetic field. The results show that, depending on the ratio of the focusing length and the particle's Larmor radius, the Fokker-Planck coefficient is significantly modified but agrees with the classical expression in the limit of a homogeneous mean magnetic field.
Thomson scattering diagnostic for the measurement of ion species fraction
Ross, J S; Park, H S; Amendt, A; Divol, L; Kugland, N L; Rozmus, W; Glenzer, S H
2012-05-01
Simultaneous Thomson scattering measurements of collective electron-plasma and ion-acoustic fluctuations have been utilized to determine ion species fraction from laser produced CH plasmas. The CH{sub 2} foil is heated with 10 laser beams, 500 J per beam, at the Omega Laser facility. Thomson scattering measurements are made 4 mm from the foil surface using a 30 J 2{omega} probe laser with a 1 ns pulse length. Using a series of target shots the plasma evolution is measured from 2.5 ns to 9 ns after the rise of the heater beams. Measuring the electron density and temperature from the electron-plasma fluctuations constrains the fit of the two-ion species theoretical form factor for the ion feature such that the ion temperature, plasma flow velocity and ion species fraction are determined. The ion species fraction is determined to an accuracy of {+-}0.06 in species fraction.
Structuring Materials on Multiple Length Scales for Energy Application...
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Structuring Materials on Multiple Length Scales for Energy Applications October 25, 2012 at 3pm36-428 Adreas Stein Department of Chemistry, University of Minnesota astein...
Ultra-low-loss tapered optical fibers with minimal lengths
Ryutaro Nagai; Takao Aoki
2014-11-09
We design and fabricate ultra-low-loss tapered optical fibers (TOFs) with minimal lengths. We first optimize variations of the torch scan length using the flame-brush method for fabricating TOFs with taper angles that satisfy the adiabaticity criteria. We accordingly fabricate TOFs with optimal shapes and compare their transmission to TOFs with a constant taper angle and TOFs with an exponential shape. The highest transmission measured for TOFs with an optimal shape is in excess of 99.7 % with a total TOF length of only 23 mm, whereas TOFs with a constant taper angle of 2 mrad reach 99.6 % transmission for a 63 mm TOF length.
Quantum Measurements of Scattered Particles
Marco Merkli; Mark Penney
2015-03-20
We investigate the process of quantum measurements on scattered probes. Before scattering, the probes are independent, but they become entangled afterwards, due to the interaction with the scatterer. The collection of measurement results (the history) is a stochastic process of dependent random variables. We link the asymptotic properties of this process to spectral characteristics of the dynamics. We show that the process has decaying time correlations and that a zero-one law holds. We deduce that if the incoming probes are not sharply localized with respect to the spectrum of the measurement operator, then the process does not converge. Nevertheless, the scattering modifies the measurement outcome frequencies, which are shown to be the average of the measurement projection operator, evolved for one interaction period, in an asymptotic state. We illustrate the results on a truncated Jaynes-Cummings model.
Crandall, David Lynn
2011-08-16
Sighting optics include a front sight and a rear sight positioned in a spaced-apart relation. The rear sight includes an optical element having a first focal length and a second focal length. The first focal length is selected so that it is about equal to a distance separating the optical element and the front sight and the second focal length is selected so that it is about equal to a target distance. The optical element thus brings into simultaneous focus for a user images of the front sight and the target.
Equilibrium Tail Distribution Due to Touschek Scattering
Nash,B.; Krinsky, S.
2009-05-04
Single large angle Coulomb scattering is referred to as Touschek scattering. In addition to causing particle loss when the scattered particles are outside the momentum aperture, the process also results in a non-Gaussian tail, which is an equilibrium between the Touschek scattering and radiation damping. Here we present an analytical calculation for this equilibrium distribution.
Light and Color in Nature -Scattering Effects -
Assarsson, Ulf
1 Seminar WS 2003/04 Light and Color in Nature - Scattering Effects - Marcus Magnor WS03/04: Light and Color in Nature Scattering Overview · Last Lecture Interference · Today Light scattering: water rendering #12;2 WS03/04: Light and Color in Nature Scattering List of Topics · Rainbow Stephan
RisR1125(EN) Neutron Scattering
RisřR1125(EN) Neutron Scattering Studies of Modulated Magnetic Structures Steen Aagaard Sřrensen investigations of the magnetic systems DyFe4Al8 and MnSi by neutron scattering and in the former case also by X and the correlations between the scattering entities of the sample. The theoretical framework of neutron scattering
T Cell Renewal Rates, Telomerase, and Telomere Length Shortening1
de Boer, Rob J.
T Cell Renewal Rates, Telomerase, and Telomere Length Shortening1 Rob J. De Boer2 and Andre´ J develop mathematic models describing how the population average of telomere length depends on the cell division rates of naive and memory T cells during clonal expansion and normal renewal. The results show
Biophysics of filament length regulation by molecular motors
Hui-Shun Kuan; M. D. Betterton
2013-02-13
Regulating physical size is an essential problem that biological organisms must solve from the subcellular to the organismal scales, but it is not well understood what physical principles and mechanisms organisms use to sense and regulate their size. Any biophysical size-regulation scheme operates in a noisy environment and must be robust to other cellular dynamics and fluctuations. This work develops theory of filament length regulation inspired by recent experiments on kinesin-8 motor proteins, which move with directional bias on microtubule filaments and alter microtubule dynamics. Purified kinesin-8 motors can depolymerize chemically-stabilized microtubules. In the length-dependent depolymerization model, the rate of depolymerization tends to increase with filament length, because long filaments accumulate more motors at their tips and therefore shorten more quickly. When balanced with a constant filament growth rate, this mechanism can lead to a fixed polymer length. However, the mechanism by which kinesin-8 motors affect the length of dynamic microtubules in cells is less clear. We study the more biologically realistic problem of microtubule dynamic instability modulated by a motor-dependent increase in the filament catastrophe frequency. This leads to a significant decrease in the mean filament length and a narrowing of the filament length distribution. The results improve our understanding of the biophysics of length regulation in cells.
On Termination and Derivation Lengths for Ground Rewrite Systems
Giesl, Juergen
On Termination and Derivation Lengths for Ground Rewrite Systems Dieter Hofbauer 1 UniversitÂ¨at GH@theory.informatik.uniÂkassel.de Abstract. It is shown that for terminating ground term rewrite systems the length of derivations a suitable interpretation into the natural numbers. Terminating ground systems are not necessarily
How Salmonella Typhimurium measure the length of their Flagellar Filaments
Keener, James P.
How Salmonella Typhimurium measure the length of their Flagellar Filaments J. P. Keener Department and length regulation of the fil- ament of the flagellar motor of Salmonella Typhimurium. Under of Salmonella Typhimurium is an example of an organelle that is built to exacting standards. Morphologically
Explanation of the Random Lengths Framing Lumber Composite Price
Explanation of the Random Lengths Framing Lumber Composite Price May 10, 2006 The Random Lengths Framing Lumber Composite is a broad measure of price behavior in the U.S. framing lumber market prices, 33% comes from Western U.S. prices, and 34% comes from Canadian prices. The Composite does
Scaling Behavior and Equilibrium Lengths of Knotted Polymers
California at Santa Barbara, University of
Scaling Behavior and Equilibrium Lengths of Knotted Polymers Eric Rawdon Akos Dobay John C. Kern numerical simulations to investigate how the chain length and topology of freely fluctuating knotted polymer of a characteristic changes with the chain size and how this change depends on the topology of the modeled polymers
Electromagnetic wave scattering by Schwarzschild black holes
Luís C. B. Crispino; Sam R. Dolan; Ednilton S. Oliveira
2009-05-20
We analyze the scattering of a planar monochromatic electromagnetic wave incident upon a Schwarzschild black hole. We obtain accurate numerical results from the partial wave method for the electromagnetic scattering cross section, and show that they are in excellent agreement with analytical approximations. The scattering of electromagnetic waves is compared with the scattering of scalar, spinor and gravitational waves. We present a unified picture of the scattering of all massless fields for the first time.
Scattering apodizer for laser beams
Summers, M.A.; Hagen, W.F.; Boyd, R.D.
1984-01-01
A method is disclosed for apodizing a laser beam to smooth out the production of diffraction peaks due to optical discontinuities in the path of the laser beam, such method comprising introduction of a pattern of scattering elements for reducing the peak intensity in the region of such optical discontinuities, such pattern having smoothly tapering boundaries in which the distribution density of the scattering elements is tapered gradually to produce small gradients in the distribution density, such pattern of scattering elements being effective to reduce and smooth out the diffraction effects which would otherwise be produced. The apodizer pattern may be produced by selectively blasting a surface of a transparent member with fine abrasive particles to produce a multitude of minute pits. In one embodiment, a scattering apodizer pattern is employed to overcome diffraction patterns in a multiple element crystal array for harmonic conversion of a laser beam. The interstices and the supporting grid between the crystal elements are obscured by the gradually tapered apodizer pattern of scattering elements.
Scattering apodizer for laser beams
Summers, Mark A. (Livermore, CA); Hagen, Wilhelm F. (Livermore, CA); Boyd, Robert D. (Livermore, CA)
1985-01-01
A method is disclosed for apodizing a laser beam to smooth out the production of diffraction peaks due to optical discontinuities in the path of the laser beam, such method comprising introduction of a pattern of scattering elements for reducing the peak intensity in the region of such optical discontinuities, such pattern having smoothly tapering boundaries in which the distribution density of the scattering elements is tapered gradually to produce small gradients in the distribution density, such pattern of scattering elements being effective to reduce and smooth out the diffraction effects which would otherwise be produced. The apodizer pattern may be produced by selectively blasting a surface of a transparent member with fine abrasive particles to produce a multitude of minute pits. In one embodiment, a scattering apodizer pattern is employed to overcome diffraction patterns in a multiple element crystal array for harmonic conversion of a laser beam. The interstices and the supporting grid between the crystal elements are obscured by the gradually tapered apodizer pattern of scattering elements.
Finite volume effects in low-energy neutron-deuteron scattering
Alexander Rokash; Evgeny Epelbaum; Hermann Krebs; Dean Lee; Ulf-G. Meißner
2013-08-15
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.
Quantifying entanglement with scattering experiments
O. Marty; M. Epping; H. Kampermann; D. Bruß; M. B. Plenio; M. Cramer
2013-10-03
We show how the entanglement contained in states of spins arranged on a lattice may be quantified with observables arising in scattering experiments. We focus on the partial differential cross-section obtained in neutron scattering from magnetic materials but our results are sufficiently general such that they may also be applied to, e.g., optical Bragg scattering from ultracold atoms in optical lattices or from ion chains. We discuss resonating valence bond states and ground and thermal states of experimentally relevant models--such as Heisenberg, Majumdar-Ghosh, and XY model--in different geometries and with different spin numbers. As a by-product, we find that for the one-dimensional XY model in a transverse field such measurements reveal factorization and the quantum phase transition at zero temperature.
J. M. Harris; G. R. S. Iyer; D. O. Simien; J. A. Fagan; J. Y. Huh; J. Y. Chung; S. D. Hudson; J. Obrzut; J. F. Douglas; C. M. Stafford; E. K. Hobbie
2011-01-01
Single-wall carbon nanotube (SWCNT) films show significant promise for transparent electronics applications that demand mechanical flexibility, but durability remains an outstanding issue. In this work, thin membranes of length purified single-wall carbon nanotubes (SWCNTs) are uniaxially and isotropically compressed by depositing them on prestrained polymer substrates. Upon release of the strain, the topography, microstructure, and conductivity of the films are characterized using a combination of optical/fluorescence microscopy, light scattering, force microscopy, electron microscopy, and impedance spectroscopy. Above a critical surface mass density, films assembled from nanotubes of well-defined length exhibit a strongly nonlinear mechanical response. The measured strain dependence reveals a dramatic softening that occurs through an alignment of the SWCNTs normal to the direction of prestrain, which at small strains is also apparent as an anisotropic increase in sheet resistance along the same direction. At higher strains, the membrane conductivities increase due to a compression-induced restoration of conductive pathways. Our measurements reveal the fundamental mode of elasto-plastic deformation in these films and suggest how it might be suppressed.
Hydrogen atom in momentum space with a minimal length
Djamil Bouaziz; Nourredine Ferkous
2010-09-05
A momentum representation treatment of the hydrogen atom problem with a generalized uncertainty relation,which leads to a minimal length ({\\Delta}X_{i})_{min}= \\hbar \\sqrt(3{\\beta}+{\\beta}'), is presented. We show that the distance squared operator can be factorized in the case {\\beta}'=2{\\beta}. We analytically solve the s-wave bound-state equation. The leading correction to the energy spectrum caused by the minimal length depends on \\sqrt{\\beta}. An upper bound for the minimal length is found to be about 10^{-9} fm.
Minimal Length Effects on Tunnelling from Spherically Symmetric Black Holes
Benrong Mu; Peng Wang; Haitang Yang
2015-01-24
In this paper, we investigate effects of the minimal length on quantum tunnelling from spherically symmetric black holes using the Hamilton-Jacobi method incorporating the minimal length. We first derive the deformed Hamilton-Jacobi equations for scalars and fermions, both of which have the same expressions. The minimal length correction to the Hawking temperature is found to depend on the black hole's mass and the mass and angular momentum of emitted particles. Finally, we calculate a Schwarzschild black hole's luminosity and find the black hole evaporates to zero mass in infinite time.
Minimal Length Effects on Tunnelling from Spherically Symmetric Black Holes
Mu, Benrong; Yang, Haitang
2015-01-01
In this paper, we investigate effects of the minimal length on quantum tunnelling from spherically symmetric black holes using the Hamilton-Jacobi method incorporating the minimal length. We first derive the deformed Hamilton-Jacobi equations for scalars and fermions, both of which have the same expressions. The minimal length correction to the Hawking temperature is found to depend on the black hole's mass and the mass and angular momentum of emitted particles. Finally, we calculate a Schwarzschild black hole's luminosity and find the black hole evaporates to zero mass in infinite time.
Laskar, Junaid M; Philip, John
2015-01-01
The ability to control the light matter interaction and simultaneous tuning of both structural order and disorder in materials, although are important in photonics, but still remain as major challenges. In this paper, we show that optical path length dictates light-matter interaction in the same crystal structure formed by the ordering of magnetic nanoparticle self-assembled columns inside magnetic nanofluid under applied field. When the optical path length (L=80 {\\mu}m) is shorter than the optical (for wavelength, {\\lambda}=632.8 nm) coherence length inside the magnetic nanofluid under applied field, a Debye diffraction ring pattern is observed; while for longer path length (L=1mm), a corona ring of scattered light is observed. Analysis of Debye diffraction ring pattern suggests the formation of 3D hexagonal crystal structure, where the longitudinal and lateral inter-column spacings are 5.281 and 7.344 microns, respectively. Observation of speckles within the Debye diffraction pattern confirms the presence o...
Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group
neutrinoless double beta decay and measure solar neutrinos and geoneutrinos. The type of particle by ap- proximately 9500 PMTs. For detections of neutrinoless double beta decay, the liquid scintillator double beta decay, low energy solar neutrinos, geo- neutrinos and supernova neutrinos using scintillation
Yu, Edward T.
of QDs in the context of our work is attractive for achieving long wavelength absorption in solar cells enhancement at all infrared wave- lengths in the device photocurrent spectrum. Epitaxial layer structuresImproved performance of In,,Ga...As/GaAs quantum dot solar cells via light scattering
Applying Vocal Tract Length Normalization to Meeting Recordings
Garau, Giulia; Renals, Steve; Hain, Thomas
2005-01-01
Vocal Tract Length Normalisation (VTLN) is a commonly used technique to normalise for inter-speaker variability. It is based on the speaker-specific warping of the frequency axis, parameterised by a scalar warp factor. ...
FEL GAIN LENGTH AND TAPER MEASUREMENTS AT LCLS
Ratner, D.
2010-01-01
taper mea- surements from LCLS. We ?nd gain lengths of ? 2.9AND TAPER MEASUREMENTS AT LCLS ? D. Ratner † , A. Brachmann,et al. , First Results of the LCLS Laser-Heater Sys- tem,
Inferring the Rate-Length Law of Protein Folding
Lane, Thomas J
2013-01-01
We investigate the rate-length scaling law of protein folding, a key undetermined scaling law in the analytical theory of protein folding. We demonstrate that chain length is a dominant factor determining folding times, and that the unambiguous determination of the way chain length corre- lates with folding times could provide key mechanistic insight into the folding process. Four specific proposed laws (power law, exponential, and two stretched exponentials) are tested against one an- other, and it is found that the power law best explains the data. At the same time, the fit power law results in rates that are very fast, nearly unreasonably so in a biological context. We show that any of the proposed forms are viable, conclude that more data is necessary to unequivocally infer the rate-length law, and that such data could be obtained through a small number of protein folding experiments on large protein domains.
FEL GAIN LENGTH AND TAPER MEASUREMENTS AT LCLS
Ratner, D.
2010-01-01
more than double the coherent, FEL power over the satura-FEL GAIN LENGTH AND TAPER MEASUREMENTS AT LCLS ? D.Figure 11: Post-saturation FEL pulse energy for a taper with
Antenna mechanism of length control of actin cables
Lishibanya Mohapatra; Bruce L. Goode; Jane Kondev
2015-05-02
Actin cables are linear cytoskeletal structures that serve as tracks for myosin-based intracellular transport of vesicles and organelles in both yeast and mammalian cells. In a yeast cell undergoing budding, cables are in constant dynamic turnover yet some cables grow from the bud neck toward the back of the mother cell until their length roughly equals the diameter of the mother cell. This raises the question: how is the length of these cables controlled? Here we describe a novel molecular mechanism for cable length control inspired by recent experimental observations in cells. This antenna mechanism involves three key proteins: formins, which polymerize actin, Smy1 proteins, which bind formins and inhibit actin polymerization, and myosin motors, which deliver Smy1 to formins, leading to a length-dependent actin polymerization rate. We compute the probability distribution of cable lengths as a function of several experimentally tuneable parameters such as the formin-binding affinity of Smy1 and the concentration of myosin motors delivering Smy1. These results provide testable predictions of the antenna mechanism of actin-cable length control.
Scattering of scalar waves on a single crystalline plane
V. K. Ignatovich
2013-08-06
Scattering of a scalar particle on a crystalline plane with quadratic cell and identical fixed scatterers is solved precisely. Contradiction of the standard scattering theory is pointed out.
Neutron inelastic scattering in natural Pb as a background in...
Office of Scientific and Technical Information (OSTI)
SCATTERING; ISOTOPES; LEAD; LEAD 206; LEAD 207; LEVELS; NEUTRONS; SCATTERING Inelastic neutron scattering on Pb isotopes can result in gamma rays near the signature endpoint...
Deep--elastic scattering and asymptotics
S. M. Troshin; N. E. Tyurin
2012-01-20
Deep--elastic scattering and its role in discrimination of the possible absorptive and reflective asymptotic scattering mechanisms are discussed with emphasis on the difference in the experimental signatures related to production processes.
Coherent scattering from a free gas
Sanders, Scott N.
We investigate decoherence in atom interferometry due to scattering from a background gas and show that the supposition that residual coherence is due to near-forward scattering is incorrect. In fact, the coherent part is ...
10th LANSCE School on Neutron Scattering
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
10th LANSCE School on Neutron Scattering LANSCE 10th LANSCE School on Neutron Scattering Home Abstract Lecturers Hands-On Experiments Free Day About the School Sponsors FAQ's...
Focusing polychromatic light through strongly scattering media
.1080) Active or adaptive optics; (290.1990) Diffusion; (290.4210) Multiple scattering; (290.7050) Turbid media
Scattering Properties of nanostructures : applications to photovoltaics
Derkacs, Daniel
2009-01-01
improvements for nanoparticle scattering coupling efficiency and photocurrent enhancement are anticipated for quantum-well solar cell
Measurements of the Thermal Neutron Scattering Kernel
Danon, Yaron
Measurements of the Thermal Neutron Scattering Kernel Li (Emily) Liu, Yaron Danon, Bjorn Becker and discussions Problems and Future study Questions #12;3 M. Mattes and J. Keinert, Thermal Neutron Scattering experimental data used was from 1973-1974! M. Mattes and J. Keinert, Thermal Neutron Scattering Data
Neutron Scattering Studies of Correlated Electron Systems
Boothroyd, Andrew
Neutron Scattering Studies of Correlated Electron Systems Lucy Helme Thesis submitted submitted for the Degree of Doctor of Philosophy, Trinity Term 2006 This thesis presents neutron scatteringO2, through inelastic neutron scattering studies of the crystal field transitions above and below
Lauren Bains August 27, 2002 Differential Scattering Cross Sections of Photons Scattered
Saskatchewan, University of
Lauren Bains August 27, 2002 Differential Scattering Cross Sections of Photons Scattered from Compton scattering of high energy photons off of oxygen nuclei (Saskatchewan Accelerator Laboratory (SAL) Experiment 056). Nuclear Compton scattering occurs when a photon with some initial momentum interacts
Alekseev, A E; Potapov, V T
2013-10-31
Spectral characteristics of the noise intensity fluctuations at the output of a scattered-light interferometer, caused by phase fluctuations of semiconductor laser radiation are considered. This kind of noise is one of the main factors limiting sensitivity of interferometric sensors. For the first time, to our knowledge, the expression is obtained for the average noise power spectral density at the interferometer output versus the degree of a light source coherence and length of the scattering segment. Also, the approximate expressions are considered which determine the power spectral density in the low-frequency range (up to 200 kHz) and in the limiting case of extended scattering segments. The expression obtained for the noise power spectral density agrees with experimental normalised power spectra with a high accuracy. (interferometry of radiation)
Feedback Mechanism for Microtubule Length Regulation by Stathmin Gradients
Maria Zeitz; Jan Kierfeld
2014-12-09
We formulate and analyze a theoretical model for the regulation of microtubule (MT) polymerization dynamics by the signaling proteins Rac1 and stathmin. In cells, the MT growth rate is inhibited by cytosolic stathmin, which, in turn, is inactivated by Rac1. Growing MTs activate Rac1 at the cell edge, which closes a positive feedback loop. We investigate both tubulin sequestering and catastrophe promotion as mechanisms for MT growth inhibition by stathmin. For a homogeneous stathmin concentration in the absence of Rac1, we find a switch-like regulation of the MT mean length by stathmin. For constitutively active Rac1 at the cell edge, stathmin is deactivated locally, which establishes a spatial gradient of active stathmin. In this gradient, we find a stationary bimodal MT length distributions for both mechanisms of MT growth inhibition by stathmin. One subpopulation of the bimodal length distribution can be identified with fast growing and long pioneering MTs in the region near the cell edge, which have been observed experimentally. The feedback loop is closed through Rac1 activation by MTs. For tubulin sequestering by stathmin, this establishes a bistable switch with two stable states: one stable state corresponds to upregulated MT mean length and bimodal MT length distributions, i.e., pioneering MTs; the other stable state corresponds to an interrupted feedback with short MTs. Stochastic effects as well as external perturbations can trigger switching events. For catastrophe promoting stathmin we do not find bistability.
Contradictions of the quantum scattering theory
V. K. Ignatovich
2006-01-23
The standard scattering theory (SST) in non relativistic quantum mechanics (QM) is analyzed. Self-contradictions of SST are deconstructed. A direct way to calculate scattering probability without introduction of a finite volume is discussed. Substantiation of SST in textbooks with the help of wave packets is shown to be incomplete. A complete theory of wave packets scattering on a fixed center is presented, and its similarity to the plane wave scattering is demonstrated. The neutron scattering on a monatomic gas is investigated, and several problems are pointed out. A catastrophic ambiguity of the cross section is revealed, and a way to resolve this ambiguity is discussed.
Pumping current of a Luttinger liquid with finite length
Sebastián Franchino Vińas; Pablo Pisani; Mariano Salvay
2012-03-16
We study transport properties in a Tomonaga-Luttinger liquid in the presence of two time-dependent point like weak impurities, taking into account finite-length effects. By employing analytical methods and performing a perturbation theory, we compute the backscattering pumping current (I_bs) in different regimes which can be established in relation to the oscillatory frequency of the impurities and to the frequency related to the length and the renormalized velocity (by the electron-electron interactions) of the charge density modes. We investigate the role played by the spatial position of the impurity potentials. We also show how the previous infinite length results for I_bs are modified by the finite size of the system.
Chaos in a well : Effects of competing length scales
R. Sankaranarayanan; A. Lakshminarayan; V. B. Sheorey
2001-06-12
A discontinuous generalization of the standard map, which arises naturally as the dynamics of a periodically kicked particle in a one dimensional infinite square well potential, is examined. Existence of competing length scales, namely the width of the well and the wavelength of the external field, introduce novel dynamical behaviour. Deterministic chaos induced diffusion is observed for weak field strengths as the length scales do not match. This is related to an abrupt breakdown of rotationally invariant curves and in particular KAM tori. An approximate stability theory is derived wherein the usual standard map is a point of ``bifurcation''.
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDidDevelopment Top LDRDUniversity PartnershipsSavannah
Diffusing-Wave Spectroscopy in a Standard Dynamic Light Scattering Setup
Zahra Fahimi; Frank Aangenendt; Panayiotis Voudouris; Johan Mattson; Hans M. Wyss
2015-09-11
Diffusing-Wave Spectroscopy (DWS) treats the transport of photons through turbid samples as a diffusion process, thereby making it possible to extract the dynamics of scatterers from measured correlation functions. The analysis of DWS data requires knowledge of the path length distribution of photons traveling through the sample. While for flat sample cells this path length distribution can be readily expressed in analytical form, no such expression is available for cylindrical sample cells. DWS measurements have therefore typically relied on dedicated setups that use flat sample cells. Here we show how DWS measurements, in particular DWS-based microrheology measurements, can be performed in standard dynamic light scattering setups that use cylindrical sample cells. To do so we perform simple random walk simulations which yield numerical predictions of the path length distribution as a function of both the transport mean free path and the detection angle. This information is used in experiments to extract the mean-square displacement of tracer particles in the material, as well as the resulting frequency-dependent viscoelastic response. An important advantage of our approach is that by measuring at different detection angles, the average photon path length can be varied. Using a single sample cell, this gives access to a wider range of length and time scales than obtained in a conventional DWS setup. Such angle-dependent measurements also offer an important consistency check, as for all detection angles the DWS analysis should yield the same tracer dynamics, even though the respective path length distributions are very different. We validate our approach by performing measurements both on aqueous suspensions of tracer particles and on solid-like gelatin samples, for which we find our DWS-based microrheology data to be in excellent agreement with rheological measurements.
TIME CONSTANTS AND ELECTROTONIC LENGTH OF MEMBRANE CYLINDERS
Zucker, Robert S.
TIME CONSTANTS AND ELECTROTONIC LENGTH OF MEMBRANE CYLINDERS AND NEURONS WILFRID RALL From electrophysiological experiments. It depends upon the several time con- stants present in passive decay of membrane membrane time constant, Tm = RmCm, observed in the decay of a uniform membrane potential, there exist many
TECHNICAL NOTES Determination of Length of a Horizontal Drain
Chahar, B. R.
(Sherard et al. 1967; Sharma 1991) suggested limits for the upstream and the downstream slopes. Chahar1 Abstract: An earth dam can be prevented from a seepage failure due to softening of the downstream the downstream slope cover and the length of the downstream horizontal drain in homogeneous isotropic
Zero Capacity Region of Multidimensional Run Length Constraints
Zeger, Kenneth
there are at least consecutive zeros. An -dimensional pattern of zeros and ones arranged in an hyper For integers and satisfying , a binary sequence is said to satisfy a one-dimensional run length constraint. For , the -dimensional -constrained capacity is defined as where denotes the number of -dimensional binary rectangular
Path Length Correction for dE/dx Olushakin Olojo
Cinabro, David
Path Length Correction for dE/dx Olushakin Olojo Department of Mechanical Engineering Wayne State used in CLEO. Due to the recent use of Helium Propane gas in the drift chamber, it is now possible of 5050% ArgonEthane to 6040% HeliumPropane in the CLEO drift chamber has reduced e#ects caused
Holographic Screening Length in a Hot Plasma of Two Sphere
Ardian Nata Atmaja; Hasan Abu Kassim; Norhasliza Yusof
2015-04-16
We study the screening length of a quark-antiquark pair moving in a hot plasma living in two sphere $S^2$ manifold using AdS/CFT correspondence where the background metric is four dimensional Schwarzschild-AdS black hole. The geodesic solution of the string ends at the boundary is given by a stationary motion in the equatorial plane as such the separation length $L$ of quark-antiquark pair is parallel to the angular velocity $\\omega$. The screening length and the bound energy are computed numerically using Mathematica. We find that the plots are bounded from below by some functions related to the momentum transfer $P_c$ of the drag force configuration. We compare the result by computing the screening length in the quark-antiquark reference frame where the gravity dual are "Boost-AdS" and Kerr-AdS black holes. Finding relations of the parameters of both black holes, we argue that the relation between mass parameters $M_{Sch}$ of the Schwarzschild-AdS black hole and $M_{Kerr}$ of the Kerr-AdS black hole in high temperature is given by $M_{Kerr}=M_{Sch}(1-a^2l^2)^{3/2}$, where $a$ is the angular momentum parameter.
Introduction Fracture at small length scales is a concern
Suo, Zhigang
Introduction Fracture at small length scales is a concern in many advanced technologies. Micro. These constrained geometries localize cracking so that fracture may not compromise the structural integrity functions. For example, lo- calized fracture of a dielectric film adjacent to a conducting line
Scaling Behavior and Equilibrium Lengths of Knotted Polymers Eric Rawdon,
Bigelow, Stephen
Scaling Behavior and Equilibrium Lengths of Knotted Polymers Eric Rawdon, Akos Dobay, John C. Kern fluctuating knotted polymer rings affect their various spatial characteristics such as the radius of the smallest sphere enclosing momentary configurations of simulated polymer chains. We describe how the average
Lolon, Elyezer P.
2006-04-12
Low-permeability gas wells often produce less than predicted after a fracture treatment. One of the reasons for this is that fracture lengths calculated after stimulation are often less than designed lengths. While actual fracture lengths may...
Hard Scattering Studies at Jlab
Harutyun Avagyan; Peter Bosted; Volker Burkert; Latifa Elouadrhiri
2005-09-01
We present current activities and future prospects for studies of hard scattering processes using the CLAS detector and the CEBAF polarized electron beam. Kinematic dependences of single and double spin asymmetries have been measured in a wide kinematic range at CLAS with a polarized NH{sub 3} and unpolarized liquid hydrogen targets. It has been shown that the data are consistent with factorization and observed target and beam asymmetries are in good agreement with measurements performed at higher energies, suggesting that the high energy-description of the semi-inclusive DIS process can be extended to the moderate energies of JLab measurements.
Average-Atom Thomson Scattering
Johnson, Walter R.
-Atom Approximation W. R. Johnson, Notre Dame J. Nilsen & K. T. Cheng, LLNL The cross section for Thomson scattering Average-Atom Model Divide plasma into WS cells with a nucleus and Z electrons p2 2 - Z r + V a(r) = a a(r) V(r) = VKS(n(r), r) n(r) = nb(r) + nc(r) 4r2nb(r) = nl 2(2l+1) 1+exp[( nl -Âµ)/kBT] Pnl(r)2 Z = r
Completeness for sparse potential scattering
Shen, Zhongwei
2014-01-15
The present paper is devoted to the scattering theory of a class of continuum Schrödinger operators with deterministic sparse potentials. We first establish the limiting absorption principle for both modified free resolvents and modified perturbed resolvents. This actually is a weak form of the classical limiting absorption principle. We then prove the existence and completeness of local wave operators, which, in particular, imply the existence of wave operators. Under additional assumptions on the sparse potential, we prove the completeness of wave operators. In the context of continuum Schrödinger operators with sparse potentials, this paper gives the first proof of the completeness of wave operators.
Small Angle X-Ray Scattering Detector
Hessler, Jan P.
2004-06-15
A detector for time-resolved small-angle x-ray scattering includes a nearly constant diameter, evacuated linear tube having an end plate detector with a first fluorescent screen and concentric rings of first fiber optic bundles for low angle scattering detection and an annular detector having a second fluorescent screen and second fiber optic bundles concentrically disposed about the tube for higher angle scattering detection. With the scattering source, i.e., the specimen under investigation, located outside of the evacuated tube on the tube's longitudinal axis, scattered x-rays are detected by the fiber optic bundles, to each of which is coupled a respective photodetector, to provide a measurement resolution, i.e., dq/q, where q is the momentum transferred from an incident x-ray to an x-ray scattering specimen, of 2% over two (2) orders of magnitude in reciprocal space, i.e., qmax/qmin approx=lO0.
Influence of the Environment Fluctuations on Incoherent Neutron Scattering Functions
D. J. Bicout
2001-04-09
In extending the conventional dynamic models, we consider a simple model to account for the environment fluctuations of particle atoms in a protein system and derive the elastic incoherent structure factor (EISF) and the incoherent scattering correlation function C(Q,t) for both the jump dynamics between sites with fluctuating site interspacing and for the diffusion inside a fluctuating sphere. We find that the EISF of the system (or the normalized elastic intensity) is equal to that in the absence of fluctuations averaged over the distribution of site interspacing or sphere radius a. The scattering correlation function is $C(Q,t)=\\sum_{n} \\psi(t)$, where the average is taken over the Q-dependent effective distribution of relaxation rates \\lambda_n(a) and \\psi(t) is the correlation function of the length a. When \\psi(t)=1, the relaxation of C(Q,t) is exponential for the jump dynamics between sites (since \\lambda_n(a) is independent of a) while it is nonexponential for diffusion inside a sphere.
Fast methods for inverse wave scattering problems
Lee, Jung Hoon, Ph. D. Massachusetts Institute of Technology
2008-01-01
Inverse wave scattering problems arise in many applications including computerized/diffraction tomography, seismology, diffraction/holographic grating design, object identification from radar singals, and semiconductor ...
Coupled-channel scattering on a torus
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Guo, Peng; Dudek, Jozef Jon; Edwards, Robert G.; Szczepaniak, Adam Pawel
2013-07-01
Based on the Hamiltonian formalism approach, a generalized Luscher's formula for two particle scattering in both the elastic and coupled-channel cases in moving frames is derived from a relativistic Lippmann-Schwinger equation. Some strategies for extracting scattering amplitudes for a coupled-channel system from the discrete finite-volume spectrum are discussed and illustrated with a toy model of two-channel resonant scattering. This formalism will, in the near future, be used to extract information about hadron scattering from lattice QCD computations.
Recent Studies on Inverse Medium Scattering Problems
2007-06-28
Numerical examples are presented to illustrate the efficiency and robustness of the ... Energy estimates for the scattered field are established, which provide ...
Transmission Eigenvalues in Inverse Scattering Theory
Title: Transmission Eigenvalues in Inverse Scattering Theory Abstract: The transmission eigenvalue problem is a new class of eigenvalue problems that has
Simulation and Application of Light Scattering Properties for Scatterers with Large Aspect Ratios
Sun, Bingqiang
2014-12-02
For scatterers with axial or N-fold rotational symmetry, the T-matrix is one of the most efficient techniques to obtain the scattering properties. Extended boundary condition method (EBCM) and invariant imbedding T-matrix method (II...
Lee, Wu-Jung
2013-01-01
The interpretation of echoes collected by active remote-sensing systems, such as sonar and radar, is often ambiguous due to the complexities in the scattering processes involving the scatterers, the environment, and the ...
Transport relaxation time and length scales in turbulent suspensions
P. Claudin; F. Charru; B. Andreotti
2010-11-03
We show that in a turbulent flow transporting suspended sediment, the unsaturated sediment flux $q(x,t)$ can be described by a first-order relaxation equation. From a mode analysis of the advection-diffusion equation for the particle concentration, the relaxation length and time scales of the dominant mode are shown to be the deposition length $H U/V_{\\rm fall}$ and deposition time $H/V_{\\rm fall}$, where $H$ is the flow depth, $U$ the mean flow velocity and $V_{\\rm fall}$ the sediment settling velocity. This result is expected to be particularly relevant for the case of sediment transport in slowly varying flows, where the flux is never far from saturation. Predictions are shown to be in quantitative agreement with flume experiments, for both net erosion and net deposition situations.
Dangerous implications of a minimum length in quantum gravity
Cosimo Bambi; Katherine Freese
2008-07-17
The existence of a minimum length and a generalization of the Heisenberg uncertainty principle seem to be two fundamental ingredients required in any consistent theory of quantum gravity. In this letter we show that they would predict dangerous processes which are phenomenologically unacceptable. For example, long--lived virtual super--Planck mass black holes may lead to rapid proton decay. Possible solutions of this puzzle are briefly discussed.
Critical Waves and the Length Problem of Biology
R. B. Laughlin
2015-04-17
It is pointed out that the mystery of how biological systems measure their lengths vanishes away if one premises that they have discovered a way to generate linear waves analogous to compressional sound. These can be used to detect length at either large or small scales using echo timing and fringe counting. It is shown that suitable linear chemical potential waves can, in fact, be manufactured by tuning to criticality conventional reaction-diffusion with a small number substances. Min oscillations in E. coli are cited as precedent resonant length measurement using chemical potential waves analogous to laser detection. Mitotic structures in eucaryotes are identified as candidates for such an effect at higher frequency. The engineering principle is shown to be very general and functionally the same as that used by hearing organs. PNAS Significance Statement: This paper invokes physical principles to address the question of how living things might use reaction-diffusion to measure out and regulate the many thousands of lengths required to make their body parts and internal organs. It argues that two ideas have been missing. One is that oscillation is necessary to achieve the necessary design stability and plasticity. The other is that the system must be tuned to criticality to stabilize the propagation velocity, thus enabling clocks to function as meter sticks. The broader significance is twofold: First, a fundamental piece of the machinery of life is probably invisible to present-day biochemical methods because they are too slow. Second, the simplicity of growth and form identified a century ago by D'Arcy Thompson is probably a symptom of biological engineering strategies, not primitive law.
Kucheyev, S O; Toth, M; Baumann, T F; Hamza, A V; Ilavsky, J; Knowles, W R; Thiel, B L; Tileli, V; van Buuren, T; Wang, Y M; Willey, T M
2006-06-05
We use low-vacuum scanning electron microscopy to image directly the ligament and pore size and shape distributions of representative aerogels over a wide range of length scales ({approx} 10{sup 0}-10{sup 5} nm). The images are used for unambiguous, real-space interpretation of small-angle scattering data for these complex nanoporous systems.
V. A. Babenko; N. M. Petrov
2007-04-08
The triplet and singlet low-energy parameters in the effective-range expansion for neutron--proton scattering are determined by using the latest experimental data on respective phase shifts from the SAID nucleon--nucleon database. The results differ markedly from the analogous parameters obtained on the basis of the phase shifts of the Nijmegen group and contradict the parameter values that are presently used as experimental ones. The values found with the aid of the phase shifts from the SAID nucleon--nucleon database for the total cross section for the scattering of zero-energy neutrons by protons, $\\sigma_{0}=20.426 $b, and the neutron--proton coherent scattering length, $f=-3.755 $fm, agree perfectly with the experimental cross-section values obtained by Houk, $\\sigma_{0}=20.436\\pm 0.023 $b, and experimental scattering-length values obtained by Houk and Wilson, $f=-3.756\\pm 0.009 $fm, but they contradict cross-section values of $\\sigma_{0}=20.491\\pm 0.014 $b according to Dilg and coherent-scattering-length values of $f=-3.7409\\pm 0.0011 $fm according to Koester and Nistler.
Euler Number Existing estimators for curve length in 3D are applied to a binary representation
van Vliet, Lucas J.
. This technique measures curve length in 3D and (DÂ2)-dimensional hyper- length in D-dimensional hyper oriented lines in three-dimensional space. Verwer (Verwer 1991) published recipes and results be extended to measure hyper-length in hyper-space. To allow comparison with binary length estimators we
221B Lecture Notes Scattering Theory II
Murayama, Hitoshi
Schwinger equation Eq. (1) is by pertur- bation theory, i.e., a power series expansion in the potential V . Note that) far away from the scatterer where r = |x| and k = k x r is the wave-vector of the scattered wave. Note, in the absence of the potential, | = | , or in other words, | = | + O(V ). Therefore the lowest (1st) order
The scattering problem for nonlocal potentials
Zolotarev, V A
2014-11-30
We solve the direct and inverse scattering problems for integro-differential operators which are one-dimensional perturbations of the self-adjoint second derivative operator on the half-axis. We also describe the scattering data for this class of operators. Bibliography: 28 titles.
Generating Particlelike Scattering States in Wave Transport
Rotter, Stefan
Generating Particlelike Scattering States in Wave Transport Philipp Ambichl1, Florian Libisch1.ambichl@tuwien.ac.at Algorithm to Generate Particlelike States1 Results of Numerical Simulation References Generic Scattering in general · wave spreads over entire resonator · no secure and efficient communication between A and B
Technology development for gene discovery and full-length sequencing
Marcelo Bento Soares
2004-07-19
In previous years, with support from the U.S. Department of Energy, we developed methods for construction of normalized and subtracted cDNA libraries, and constructed hundreds of high-quality libraries for production of Expressed Sequence Tags (ESTs). Our clones were made widely available to the scientific community through the IMAGE Consortium, and millions of ESTs were produced from our libraries either by collaborators or by our own sequencing laboratory at the University of Iowa. During this grant period, we focused on (1) the development of a method for preferential cloning of tissue-specific and/or rare transcripts, (2) its utilization to expedite EST-based gene discovery for the NIH Mouse Brain Molecular Anatomy Project, (3) further development and optimization of a method for construction of full-length-enriched cDNA libraries, and (4) modification of a plasmid vector to maximize efficiency of full-length cDNA sequencing by the transposon-mediated approach. It is noteworthy that the technology developed for preferential cloning of rare mRNAs enabled identification of over 2,000 mouse transcripts differentially expressed in the hippocampus. In addition, the method that we optimized for construction of full-length-enriched cDNA libraries was successfully utilized for the production of approximately fifty libraries from the developing mouse nervous system, from which over 2,500 full-ORF-containing cDNAs have been identified and accurately sequenced in their entirety either by our group or by the NIH-Mammalian Gene Collection Program Sequencing Team.
Minimum length, extra dimensions, modified gravity and black hole remnants
Maziashvili, Michael
2013-03-01
We construct a Hilbert space representation of minimum-length deformed uncertainty relation in presence of extra dimensions. Following this construction, we study corrections to the gravitational potential (back reaction on gravity) with the use of correspondingly modified propagator in presence of two (spatial) extra dimensions. Interestingly enough, for r?0 the gravitational force approaches zero and the horizon for modified Schwarzschild-Tangherlini space-time disappears when the mass approaches quantum-gravity energy scale. This result points out to the existence of zero-temperature black hole remnants in ADD brane-world model.
Pauling bond strength, bond length and electron density distribution
Gibbs, Gerald V.; Ross, Nancy L.; Cox, David F.; Rosso, Kevin M.; Iversen, Bo B.; Spackman, M. A.
2014-01-18
A power law regression equation, /r)-0.21, determined for a large number of oxide crystals at ambient conditions and /r)-0.22, determined for geometry optimized hydroxyacid molecules, that connect the bond lengths to the average Pauling electrostatic bond strength, , for the M-O bonded interactions. On the basis of the correspondence between the two sets of equations connecting ?(rc) and the Pauling bond strength s with bond length, it appears that Pauling’s simple definition of bond strength closely mimics the accumulation of the electron density between bonded pairs of atoms. The similarity of the expressions for the crystals and molecules is compelling evidence that the M-O bonded interactions for the crystals and molecules 2 containing the same bonded interactions are comparable. Similar expressions, connecting bond lengths and bond strength, have also been found to hold for fluoride, nitride and sulfide molecules and crystals. The Brown-Shannon bond valence, ?, power law expression ? = [R1/(R(M-O)]N that has found wide use in crystal chemistry, is shown to be connected to a more universal expression determined for oxides and the perovskites, = r[(1.41)/
Varying properties along lengths of temperature limited heaters
Vinegar, Harold J. (Bellaire, TX); Xie, Xueying (Houston, TX); Miller, David Scott (Katy, TX); Ginestra, Jean Charles (Richmond, TX)
2011-07-26
A system for heating a subsurface formation is described. The system includes an elongated heater in an opening in the formation. The elongated heater includes two or more portions along the length of the heater that have different power outputs. At least one portion of the elongated heater includes at least one temperature limited portion with at least one selected temperature at which the portion provides a reduced heat output. The heater is configured to provide heat to the formation with the different power outputs. The heater is configured so that the heater heats one or more portions of the formation at one or more selected heating rates.
Self-aligned submicron gate length gallium arsenide MESFET
Huang, Hsien-Ching
1987-01-01
38 21. Proximity cap annealing . 22. Temperature profile of post implant anneal 46 47 23. 24. 25. 26. 27. 28. 29. 30. "Pits" or holes in GaAs post implant anneal without sacrificial cap Silicon monoxide source (bafile box) used.... 16(b)). The bottom resist layer is then further etched in the oxygen plasma to produce undercutting for the desire gate structure. The amount of undercut is determined by the desired length of the gate and is the width of the remaining resist...
UNIVERSITY OF CALIFORNIA Inelastic Neutron Scattering Study of the
Lawrence, Jon
UNIVERSITY OF CALIFORNIA IRVINE Inelastic Neutron Scattering Study of the Intermediate Valence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Inelastic Neutron Scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.a Neutron Scattering Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.b
EXPERIMENTS ON N-P SCATTERING WITH 260 MEV NEUTRONS
Kelly, E.; Leith, C.; Segre, E.; Wiegand, C.
1950-01-01
FIG. IN MEV Mu 56 NEUTRON SCATTERING ANGLE FIG 3 Mu 57EXPERIWNTS ON N-P SCATTERING WITH 260 MEV NEUTRONS Eo Refly,EXPERIMENTS OM N-P SCATTERING WITH 260 MEV NEUTRONS E Kelly,
Fully portable, highly flexible dilution refrigerator systems for neutron scattering
Boyer, Edmond
775 Fully portable, highly flexible dilution refrigerator systems for neutron scattering P. A systems developed specifically for neutron scattering environ- ments. The refrigerators are completely relatively recently however, the lowest temperatures available in almost all neutron scattering laboratories
Jain, Dr Nirmesh [University of Sydney, Australia] [University of Sydney, Australia; Liu, Dr C K [Institute of Materials research and Engineering, A-STAR, Singapore] [Institute of Materials research and Engineering, A-STAR, Singapore; Hawkett, Dr B. S. [University of Sydney, Australia] [University of Sydney, Australia; Warr, G. G. [University of Sydney, Australia] [University of Sydney, Australia; Hamilton, William A [ORNL] [ORNL
2014-01-01
The optical magnetic chaining technique (MCT) developed by Leal-Calderon, Bibette and co-workers in the 1990 s allows precise measurements of force profiles between droplets in monodisperse ferrofluid emulsions. However, the method lacks an in-situ determination of droplet size and therefore requires the combination of separately acquired measurements of droplet chain periodicity versus an applied magnetic field from optical Bragg scattering and droplet diameter inferred from dynamic light scattering (DLS) to recover surface force-distance profiles between the colloidal particles. Compound refractive lens (CRL) focussed small-angle scattering (SANS) MCT should result in more consistent measurements of droplet size (form factor measurements in the absence of field) and droplet chaining period (from structure factor peaks when the magnetic field is applied); and, with access to shorter length scales, extend force measurements to closer approaches than possible by optical measurements. We report on CRL-SANS measurements of monodisperse ferrofluid emulsion droplets aligned in straight chains by an applied field perpendicular to the incident beam direction. Analysis of the scattering from the closely spaced droplets required algorithms that carefully treated resolution and its effect on mean scattering vector magnitudes in order to determine droplet size and chain periods to sufficient accuracy. At lower applied fields scattering patterns indicate structural correlations transverse to the magnetic field direction due to the formation of intermediate structures in early chain growth.
Li, Jing; Vitusevich, Svetlana; Pud, Sergii; Sydoruk, Viktor; Offenhäusser, Andreas; Petrychuk, Mykhailo; Danilchenko, Boris
2013-12-04
The transport properties of Si nanowire (NW) structures fabricated on the basis of silicon on insulator (SOI) wafers were studied using noise spectroscopy before and after treatment with small doses of gamma radiation. The total resistance obtained from the I-V characteristics of Si NW structures scaled perfectly with length. Normalized flicker noise demonstrated 1/L{sup 2} dependence, which is a characteristic of dominant noise contribution from near-contact regions. The behavior changed to 1/L dependence after a small dose (1×10{sup 4} Gy) of gamma radiation treatment. Comparison of the random telegraph signal (RTS) noise parameters in the samples with small lengths before and after the treatment revealed a decrease in RTS amplitude and a shift to a lower frequency range after gamma irradiation. These results confirmed that the main changes in the samples were related to strain relaxation near-contact regions. In addition, such treatment resulted in a considerable decrease in the scattering data of device parameters.
The Chain-Length Distribution in Subcritical Systems
Steven Douglas Nolen
2000-06-01
The individual fission chains that appear in any neutron multiplying system provide a means, via neutron noise analysis, to unlock a wealth of information regarding the nature of the system. This work begins by determining the probability density distributions for fission chain lengths in zero-dimensional systems over a range of prompt neutron multiplication constant (K) values. This section is followed by showing how the integral representation of the chain-length distribution can be used to obtain an estimate of the system's subcritical prompt multiplication (MP). The lifetime of the chains is then used to provide a basis for determining whether a neutron noise analysis will be successful in assessing the neutron multiplication constant, k, of the system in the presence of a strong intrinsic source. A Monte Carlo transport code, MC++, is used to model the evolution of the individual fission chains and to determine how they are influenced by spatial effects. The dissertation concludes by demonstrating how experimental validation of certain global system parameters by neutron noise analysis may be precluded in situations in which the system K is relatively low and in which realistic detector efficiencies are simulated.
Application of Neutron Imaging and Scattering to Fluid Flow and...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Application of Neutron Imaging and Scattering to Fluid Flow and Fracture in EGS Environments Application of Neutron Imaging and Scattering to Fluid Flow and Fracture in EGS...
Quasielastic Neutron Scattering Study of Water Confined in Carbon...
Office of Scientific and Technical Information (OSTI)
Quasielastic Neutron Scattering Study of Water Confined in Carbon Nanopores Citation Details In-Document Search Title: Quasielastic Neutron Scattering Study of Water Confined in...
Neutron scattering of iron-based superconductors (Journal Article...
Office of Scientific and Technical Information (OSTI)
Neutron scattering of iron-based superconductors Citation Details In-Document Search Title: Neutron scattering of iron-based superconductors Low-energy spin excitations have been...
Proton Angular Distribution for 90 Mev Neutron-proton Scattering
Hadley, James
2010-01-01
recoil protons in neutron -proton scattering at 90 Mev hasFOR 90 lWEV NEUTRON-PROTON SCATTERING James Hadley, Cecil E.
2012 LANSCE Neutron Scattering School | Los Alamos National Laboratory
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
2 LANSCE Neutron Scattering School LANSCE 2012 LANSCE Neutron Scattering School Home About the School Hands-On Experiments Quick Links Application - Closed Schedule Poster...
Neutron inelastic scattering in natural Pb as a background in...
Office of Scientific and Technical Information (OSTI)
Neutron inelastic scattering in natural Pb as a background in neutrinoless double-beta decay experiments Citation Details In-Document Search Title: Neutron inelastic scattering in...
2012 LANSCE Neutron Scattering School | Los Alamos National Laboratory
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
1 LANSCE Neutron Scattering School LANSCE 2011 LANSCE Neutron Scattering School Home NSS 2011 About the School Lecturers Hands-On Experiments Quick Links Application Schedule...
International Conference on Neutron Scattering 2005 Darling Harbour. Sydney. Australia
International Conference on Neutron Scattering 2005 Darling Harbour. Sydney. Australia 27 November, Hillerřd, Denmark Combined application of small-angle neutron scattering and oscillatory shear
Shape Reconstruction of Inverse Medium Scattering for the ...
2011-11-03
scattered wave, is developed. The algorithm requires multi-frequency data. .... The well-posedness of the direct scattering is proved, and important energy. 2 ...
WPEC subgroup 35 ""scattering angular distribution in the fast...
Office of Scientific and Technical Information (OSTI)
WPEC subgroup 35 ""scattering angular distribution in the fast energy range"" status report Citation Details In-Document Search Title: WPEC subgroup 35 ""scattering angular...
The I=2 ?? S-wave Scattering Phase Shift from Lattice QCD
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Beane, S. R.; Chang, E.; Detmold, W.; Lin, H. W.; Luu, T. C.; Orginos, K.; Parreno, A.; Savage, M. J.; Torok, A.; Walker-Loud, A.
2012-02-16
The ?+?+ s-wave scattering phase-shift is determined below the inelastic threshold using Lattice QCD. Calculations were performed at a pion mass of m? ? 390 MeV with an anisotropic nf = 2+1 clover fermion discretization in four lattice volumes, with spatial extent L ? 2.0, 2.5, 3.0 and 3.9 fm, and with a lattice spacing of bs ? 0.123 fm in the spatial direction and bt bs/3.5 in the time direction. The phase-shift is determined from the energy-eigenvalues of ?+?+ systems with both zero and non-zero total momentum in the lattice volume using Luscher's method. Our calculations are precise enoughmore »to allow for a determination of the threshold scattering parameters, the scattering length a, the effective range r, and the shape-parameter P, in this channel and to examine the prediction of two-flavor chiral perturbation theory: m?2 a r = 3+O(m?2/??2). Chiral perturbation theory is used, with the Lattice QCD results as input, to predict the scattering phase-shift (and threshold parameters) at the physical pion mass. Our results are consistent with determinations from the Roy equations and with the existing experimental phase shift data.« less
Hadronic ?Z box corrections in Mřller scattering
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Hall, Nathan L.; Blunden, Peter G.; Melnitchouk, Wally; Thomas, Anthony W.; Young, Ross D.
2014-04-01
The possibility of measuring the parity-violating asymmetry in Moller scattering with sufficient accuracy to determine sin2?W to 0.1% offers a complementary path to the discovery of new physics to that followed at high energy colliders. We present a new calculation of the ?Z box contribution to parity-violating electron-proton scattering, which constitutes an important uncertainty in computing the background to this process. We show that while the ?Z correction grows rapidly with energy, it can be relatively well constrained by data from parity-violating inelastic scattering and parton distribution functions.
Integral equations of scattering in one dimension
Vania E. Barlette; Marcelo M. Leite; Sadhan K. Adhikari
2001-03-05
A self-contained discussion of integral equations of scattering is presented in the case of centrally-symmetric potentials in one dimension, which will facilitate the understanding of more complex scattering integral equations in two and three dimensions. The present discussion illustrates in a simple fashion the concept of partial-wave decomposition, Green's function, Lippmann-Schwinger integral equations of scattering for wave function and transition operator, optical theorem and unitarity relation. We illustrate the present approach with a Dirac delta potential.
Attosecond neutron Compton scattering from protons
C. Aris Chatzidimitriou-Dreismann
2007-02-01
The effect of "anomalous" scattering of neutrons and electrons from protons in the electron-volt energy-transfer range is considered, and related experimental results are mentioned. A recent independent confirmation of this effect with a new data analysis procedure is presented. Due to the very short characteristic scattering time, there is no well defined separation of time scales of electronic and protonic motions. An outline of a proposed theoretical interpretation is presented, which is based on the fact that scattering protons represent \\textit{open} quantum systems, thus being subject to decoherence.
Thomson Scattering in the Solar Corona
Inhester, Bernd
2015-01-01
The fundaments of the application of Thomson scattering to the analysis of coronagraph images has been laid decades ago. Even though the basic formulation is undebated, a discussion has grown in recent years about the spatial distribution of Thomson scatter sensitivity in space. These notes are an attempt to clarify the understanding about this topic. We reformulate the classical calculations in a more transparent way using modern SI-compatible quantities and extend the scattering calculations to the case of relativistic electrons. Many mathematical and some basic physical ingredients are made explicit in several chapters of the appendix.
Nucleon-Nucleon Scattering Parameters in the Limit of SU(3) Flavor Symmetry
Beane, Silas; Chang, Emanuel; Savage, Martin; Lin, Huey-Wen; Orginos, Konstantinos; Cohen, Saul; Detmold, William; Luu, Tom; Parreno, Assumpta; Junnarkar, Parikshit; Walker-Loud, Andre Paul
2013-08-01
The scattering lengths and effective ranges that describe low-energy nucleon-nucleon scattering are calculated in the limit of SU(3)-flavor symmetry at the physical strange-quark mass with Lattice Quantum Chromodynamics. The calculations are performed with an isotropic clover discretization of the quark action in three volumes with spatial extents of L ~ 3.4 fm, 4.5 fm and 6.7 fm, and with a lattice spacing of b ~ 0.145 fm. With determinations of the energies of the two-nucleon systems ?both of which contain bound states at these light-quark masses? at rest and moving in the lattice volume, Luscher?s method is used to determine the low-energy phase shift in each channel, from which the scattering length and effective range are obtained. The scattering parameters in the {sup 1}S{sub 0} channel are found to be m{sub ?}a{sup ({sup 1}S{sub 0})} = 9.51+/-0.74+/-1.00 and m{sub ?}r{sup ({sup 1}S{sub 0})} = 4.76+/-0.37+/-0.40, and in the {sup 3}S{sub 1} channel are m{sub ?}a{sup ({sup 3}S{sub 1})} = 7.45+/-0.57+/-0.71 and m{sub ?}r{sup ({sup 3}S{sub 1})} = 3.71+/-0.28+/-0.28. These values are consistent with the two-nucleon system exhibiting Wigner?s supermultiplet symmetry, which becomes exact in the limit of large-N{sub c}.
Park, Y; Winey, B; Sharp, G
2014-06-01
Purpose: To demonstrate feasibility of proton dose calculation on scattercorrected CBCT images for the purpose of adaptive proton therapy. Methods: Two CBCT image sets were acquired from a prostate cancer patient and a thorax phantom using an on-board imaging system of an Elekta infinity linear accelerator. 2-D scatter maps were estimated using a previously introduced CT-based technique, and were subtracted from each raw projection image. A CBCT image set was then reconstructed with an open source reconstruction toolkit (RTK). Conversion from the CBCT number to HU was performed by soft tissue-based shifting with reference to the plan CT. Passively scattered proton plans were simulated on the plan CT and corrected/uncorrected CBCT images using the XiO treatment planning system. For quantitative evaluation, water equivalent path length (WEPL) was compared in those treatment plans. Results: The scatter correction method significantly improved image quality and HU accuracy in the prostate case where large scatter artifacts were obvious. However, the correction technique showed limited effects on the thorax case that was associated with fewer scatter artifacts. Mean absolute WEPL errors from the plans with the uncorrected and corrected images were 1.3 mm and 5.1 mm in the thorax case and 13.5 mm and 3.1 mm in the prostate case. The prostate plan dose distribution of the corrected image demonstrated better agreement with the reference one than that of the uncorrected image. Conclusion: A priori CT-based CBCT scatter correction can reduce the proton dose calculation error when large scatter artifacts are involved. If scatter artifacts are low, an uncorrected CBCT image is also promising for proton dose calculation when it is calibrated with the soft-tissue based shifting.
Analysis and Optimization of "Full-Length" Diodes
Schock, Alfred
2012-01-19
A method of analyzing the axial variation of the heat generation rate, temperature, voltage, current density and emitter heat flux in a thermionic converter is described. The method is particularly useful for the case of "long" diodes, each extending over the full length of the reactor core. For a given diode geometry and fuel distribution, the analysis combines a nuclear solution of the axial fission density profile with the iterative solution of four differential equations representing the thermal, electrical, and thermionic interactions within the diode. The digital computer program developed to solve these equations can also perform a design optimization with respect to lead resistance, load voltage, and emitter thickness, for a specified maximum emitter temperature. Typical results are presented, and the use of this analysis for predicting the diode operating characteristics is illustrated.
Light absorption cell combining variable path and length pump
Prather, W.S.
1993-12-07
A device is described for use in making spectrophotometric measurements of fluid samples. In particular, the device is a measurement cell containing a movable and a fixed lens with a sample of the fluid there between and through which light shines. The cell is connected to a source of light and a spectrophotometer via optic fibers. Movement of the lens varies the path length and also pumps the fluid into and out of the cell. Unidirectional inlet and exit valves cooperate with the movable lens to assure a one-way flow of fluid through the cell. A linear stepper motor controls the movement of the lens and cycles it from a first position closer to the fixed lens and a second position farther from the fixed lens, preferably at least 10 times per minute for a nearly continuous stream of absorption spectrum data. 2 figures.
Light absorption cell combining variable path and length pump
Prather, William S. (2419 Dickey Rd., Augusta, GA 30906)
1993-01-01
A device for use in making spectrophotometric measurements of fluid samples. In particular, the device is a measurement cell containing a movable and a fixed lens with a sample of the fluid therebetween and through which light shines. The cell is connected to a source of light and a spectrophotometer via optic fibers. Movement of the lens varies the path length and also pumps the fluid into and out of the cell. Unidirectional inlet and exit valves cooperate with the movable lens to assure a one-way flow of fluid through the cell. A linear stepper motor controls the movement of the lens and cycles it from a first position closer to the fixed lens and a second position farther from the fixed lens, preferably at least 10 times per minute for a nearly continuous stream of absorption spectrum data.
Characteristic length of an AdS/CFT superconductor
Kengo Maeda; Takashi Okamura
2008-10-30
We investigate in more detail the holographic model of a superconductor recently found by Hartnoll, Herzog, and Horowitz [Phys. Rev. Lett. 101, 031601], which is constructed from a condensate of a charged scalar field in AdS_4-Schwarzschild background. By analytically studying the perturbation of the gravitational system near the critical temperature T_c, we obtain the superconducting coherence length proportional to 1/\\sqrt{1-T/T_c} via AdS/CFT correspondence. By adding a small external homogeneous magnetic field to the system, we find that a stationary diamagnetic current proportional to the square of the order parameter is induced by the magnetic field. These results agree with Ginzburg-Landau theory and strongly support the idea that a superconductor can be described by a charged scalar field on a black hole via AdS/CFT duality.
What Does a Scattering Pattern Tell US?
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
amplitude e iwt Phase difference Phase difference S e i (ri Q) A(DK) fi A(Q) Fourier Transform ( ri ) DK Q 4p sin(q) l Lensless Imaging Sample Space Scattering Space...
Association of scattering matrices in quantum networks
Almeida, F.A.G.; Macędo, A.M.S.
2013-06-15
Algorithms based on operations that associate scattering matrices in series or in parallel (analogous to impedance association in a classical circuit) are developed here. We exemplify their application by calculating the total scattering matrix of several types of quantum networks, such as star graphs and a chain of chaotic quantum dots, obtaining results with good agreement with the literature. Through a computational-time analysis we compare the efficiency of two algorithms for the simulation of a chain of chaotic quantum dots based on series association operations of (i) two-by-two centers and (ii) three-by-three ones. Empirical results point out that the algorithm (ii) is more efficient than (i) for small number of open scattering channels. A direct counting of floating point operations justifies quantitatively the superiority of the algorithm (i) for large number of open scattering channels.
INELASTIC LIGHT SCATTERING STUDIES OF BOROCARBIDE SUPERCONDUCTORS
Yang, In-Sang
INELASTIC LIGHT SCATTERING STUDIES OF BOROCARBIDE SUPERCONDUCTORS INSANG YANG Department In recent years of studies in ``unconventional'' superconductivity, researchers have concentrated on exotic behavior of the heavy fermion and cuprate su perconductors. However, even superconductors that are thought
Neutron-deuteron breakup and quasielastic scattering
Ohlson, Alice Elisabeth
2009-01-01
Quasielastic scattering and deuteron breakup in the 200 MeV region is studied by impinging a pulsed neutron beam on a deuterium target at the Weapons Neutron Research facility at the Los Alamos Neutron Science Center. The ...
Analysis of light transport in scattering media
Mukaigawa, Yasuhiro
We propose a new method to analyze light transport in homogeneous scattering media. The incident light undergoes multiple bounces in translucent objects, and produces a complex light field. Our method analyzes the light ...
What Does a Scattering Pattern Tell US?
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
light image Image Space lens Can we create the image without a lens? Angular Space Math Q 4p sin(q) l Lensless Imaging Sample Space Scattering Space sample light image lens...
Millstone Hill Thomson Scatter Results for 1965
Evans, J. V.
1969-12-08
This report presents F-region electron densities, and electron and ion temperatures observed during the year 1965 at the Millstone Hill Radar Observatory (42.6°N. 71.5“W) by the UHF Thomson (incoherent) scatter radar. The ...
Millstone Hill Thomson Scatter Results for 1964
Evans, J. V.
1967-11-15
Thomson scatter (incoherent backscatter) observations of the ionosphere were made at Millstone Hill at a wavelength of 68 cm during 1964, for 30-hour periods every two weeks. These data have been employed to derive the ...
INVERSE SCATTERING PROBLEMS WITH MULTI-FREQUENCIES ...
2015-01-25
variational problem is studied for the direct scattering; an energy estimate is given to ... with some general remarks and directions for future research in section 4. ... alternative theorem, the direct problem can be shown to have a unique weak ...
Scattering by coupled resonating elements in air
Anton Krynkin; Olga Umnova; Alvin Y. B. Chong; Shahram Taherzadeh; Keith Attenborough
2011-01-12
Scattering by (a) a single composite scatterer consisting of a concentric arrangement of an outer N-slit rigid cylinder and an inner cylinder which is either rigid or in the form of a thin elastic shell and (b) by a finite periodic array of these scatterers in air has been investigated analytically and through laboratory experiments. The composite scatterer forms a system of coupled resonators and gives rise to multiple low frequency resonances. The corresponding analytical model employs polar angle dependent boundary conditions on the surface of the N-slit cylinder. The solution inside the slits assumes plane waves. It is shown also that in the low-frequency range the N-slit rigid cylinder can be replaced by an equivalent fluid layer. Further approximations suggest a simple square root dependence of the resonant frequencies on the number of slits and this is confirmed by data. The observed resonant phenomena are associated with Helmholtz-like behaviour of the resonator for which the radius and width of the openings are much smaller than the wavelength. The problem of scattering by a finite periodic array of such coupled resonators in air is solved using multiple scattering techniques. The resulting model predicts band-gap effects resulting from the resonances of the individual composite scatterers below the first Bragg frequency . Predictions and data confirm that use of coupled resonators results in substantial insertion loss peaks related to the resonances within the concentric configuration. In addition, for both scattering problems experimental data, predictions of the analytical approach and predictions of the equivalent fluid layer approximations are compared in the low-frequency interval.
Quantum Energy Regression using Scattering Transforms
Matthew Hirn; Nicolas Poilvert; Stephane Mallat
2015-02-06
We present a novel approach to the regression of quantum mechanical energies based on a scattering transform of an intermediate electron density representation. A scattering transform is a deep convolution network computed with a cascade of multiscale wavelet transforms. It possesses appropriate invariant and stability properties for quantum energy regression. This new framework removes fundamental limitations of Coulomb matrix based energy regressions, and numerical experiments give state-of-the-art accuracy over planar molecules.
Quantum Energy Regression using Scattering Transforms
Hirn, Matthew; Mallat, Stephane
2015-01-01
We present a novel approach to the regression of quantum mechanical energies based on a scattering transform of an intermediate electron density representation. A scattering transform is a deep convolution network computed with a cascade of multiscale wavelet transforms. It possesses appropriate invariant and stability properties for quantum energy regression. This new framework removes fundamental limitations of Coulomb matrix based energy regressions, and numerical experiments give state-of-the-art accuracy over planar molecules.
Deep Inelastic Scattering -- Theory and Phenomenology
B. R. Webber
1996-07-26
Recent developments in theory and phenomenology relevant to deep inelastic lepton scattering are reviewed, concentrating on the following topics: Predicted behaviour of non-singlet and polarized structure functions at small $x$; Theoretical studies of saturation and unitarity effects at small $x$ in quarkonium scattering; Renormalons and higher twist contributions; Next-to-leading-order calculations of jet cross sections; Forward jet production as a probe of small-$x$ dynamics.
Integration Rules for Loop Scattering Equations
Baadsgaard, Christian; Bourjaily, Jacob L; Damgaard, Poul H; Feng, Bo
2015-01-01
We formulate new integration rules for one-loop scattering equations analogous to those at tree-level, and test them in a number of non-trivial cases for amplitudes in scalar $\\phi^3$-theory. This formalism greatly facilitates the evaluation of amplitudes in the CHY representation at one-loop order, without the need to explicitly sum over the solutions to the loop-level scattering equations.
Light-scattering studies of silica aerogels
Hunt, A.J.
1983-02-01
Due to its combination of transparency and low thermal conductivity, aerogel holds considerable promise for use as insulating window materials for residential and commercial applications. This paper reports on the preliminary investigation of the optical and scattering properties of silica aerogels. It briefly describes the properties of aerogels important for window glazing applications. The optical properties are then described, followed by a discussion of the scattering measurements and their interpretation.
Symmetry Algebra of IIB Superstring Scattering
Gordon Chalmers
2005-10-26
The graviton scattering in IIB superstring theory is examined in the context of S-duality and symmetry. There is an algebra that generates all of the terms in the four-point function to any order in derivatives. A map from the algebra to the scattering is given; it suggests the correctness of the full four-point function with the S-duality. The higher point functions are expected to follow a similar pattern.
Wilson, David J.
2014-06-23
We have obtained clear signals of resonances in coupled-channel pi K - eta K scattering. Using distillation and a large basis of operators we are able to extract a precise spectrum of energy levels using the variational method. These energies are analysed using inelastic extensions of the Luescher method to obtain scattering amplitudes that clearly describe S, P and D wave resonances, corresponding to the physical K_0^*(1430), the K^*(892) and the K_2^*(1430).
Fact #728: May 21, 2012 Average Trip Length is Less Than Ten Miles
Broader source: Energy.gov [DOE]
The average trip length (one-way) is 9.7 miles according to the 2009 Nationwide Personal Transportation Survey. Trip lengths vary by the purpose of the trip. Shopping and family/personal business...
Neutron and X-ray Scattering Study of Magnetic Manganites
Boothroyd, Andrew
Neutron and X-ray Scattering Study of Magnetic Manganites Graeme Eoin Johnstone A Thesis submitted are performed using a variety of neutron scattering and x-ray scattering techniques. The electronic ground for analysing the results of the polarised neutron scattering experiment. There are a large number of people who
Neutron scattering at high pressure D. B. McWhan
Paris-Sud XI, Université de
715 Neutron scattering at high pressure D. B. McWhan Room 1D-234, Murray Hill, New Jersey 07974, U scattering at steady-state and pulsed sources are reviewed. The pressure cells available at most neutron 10 GPa have been made. For elastic scattering, a comparison is made between neutron scattering and X
Static and Dynamic Light Scattering G. C. Berry
Kurnikova, Maria
copolymers or very low molecular weight polymers), for polyelectrolytes dissolved in an electrolyte9/23/97 Static and Dynamic Light Scattering G. C. Berry Department of Chemistry Carnegie Mellon 1 SCATTERING RELATIONS 2 Scattered Intensity Measures 2 Static Scattering Relations 2 Dynamic
Fault Detection Likelihood of Test Sequence Length Fevzi Belli, Michael Linschulte
Belli, Fevzi
accepted hypothesis is that the longer the test sequences, the higher the chances to detect faults. However the length of test sequences. · For our experiments the length of sequences varied from 2 to 4, definingFault Detection Likelihood of Test Sequence Length Fevzi Belli, Michael Linschulte University
QueueTrak: Automated Line Length Detection using a Wireless Sensor Network
Whitehouse, Kamin
, it uses a series of custom active infrared sensors to detect the length of a line in a store or restaurant the design, implementation, and evaluation of QueueTrak, a sensor network that measures the length of linesQueueTrak: Automated Line Length Detection using a Wireless Sensor Network Jared Alexander, Matthew
NON-DESTRUCTIVE SINGLE SHOT BUNCH LENGTH MEASUREMENTS FOR THE CLIC TEST FACILITY 3
NON-DESTRUCTIVE SINGLE SHOT BUNCH LENGTH MEASUREMENTS FOR THE CLIC TEST FACILITY 3 A. Dabrowski, M and P. Urschütz, CERN, Geneva, Switzerland Abstract A non-destructive bunch length detector has been has been made at CTF3 to develop a non destructive single shot bunch length monitor. This device
THE DISTRIBUTION OF THE COMBINED LENGTH OF SPANNED CYCLES IN A
Hart, Sergiu
THE DISTRIBUTION OF THE COMBINED LENGTH OF SPANNED CYCLES IN A RANDOM PERMUTATION By YANNAI A of the combined length L = L(, M) of all cycles of that contain at least one element of M. We give a simple-MAIL: ratio@math.huji.ac.il URL: http://www.ratio.huji.ac.il/ #12;The Distribution of the Combined Length
Pore accessibility by methane and carbon dioxide in coal as determined by neutron scattering
He, Lilin [ORNL; Melnichenko, Yuri B [ORNL; Mastalerz, Maria [Indiana Geological Survey; Sakurovs, Richard [ORNL; Radlinski, Andrzej Pawell [ORNL; Blach, Tomasz P [ORNL
2012-01-01
Contrast-matching ultrasmall-angle neutron scattering (USANS) and small-angle neutron scattering (SANS) techniques were used for the first time to determine both the total pore volume and the fraction of the pore volume that is inaccessible to deuterated methane, CD{sub 4}, in four bituminous coals in the range of pore sizes between {approx}10 {angstrom} and {approx}5 {micro}m. Two samples originated from the Illinois Basin in the U.S.A., and the other two samples were commercial Australian bituminous coals from the Bowen Basin. The total and inaccessible porosity were determined in each coal using both Porod invariant and the polydisperse spherical particle (PDSP) model analysis of the scattering data acquired from coals both in vacuum and at the pressure of CD{sub 4}, at which the scattering length density of the pore-saturating fluid is equal to that of the solid coal matrix (zero average contrast pressure). The total porosity of the coals studied ranged from 7 to 13%, and the volume of pores inaccessible to CD{sub 4} varied from {approx}13 to {approx}36% of the total pore volume. The volume fraction of inaccessible pores shows no correlation with the maceral composition; however, it increases with a decreasing total pore volume. In situ measurements of the structure of one coal saturated with CO{sub 2} and CD{sub 4} were conducted as a function of the pressure in the range of 1-400 bar. The neutron scattering intensity from small pores with radii less than 35 {angstrom} in this coal increased sharply immediately after the fluid injection for both gases, which demonstrates strong condensation and densification of the invading subcritical CO{sub 2} and supercritical methane in small pores.
Length Scale Selects Directionality of Droplets on Vibrating Pillar Ratchet
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Agapov, Rebecca L.; Boreyko, Jonathan B.; Briggs, Dayrl P.; Srijanto, Bernadeta R.; Retterer, Scott T.; Collier, Pat; Lavrik, Nickolay V.
2014-09-22
Directional control of droplet motion at room temperature is of interest for applications such as microfluidic devices, self-cleaning coatings, and directional adhesives. Here, arrays of tilted pillars ranging in height from the nanoscale to the microscale are used as structural ratchets to directionally transport water at room temperature. Water droplets deposited on vibrating chips with a nanostructured ratchet move preferentially in the direction of the feature tilt while the opposite directionality is observed in the case of microstructured ratchets. This remarkable switch in directionality is consistent with changes in the contact angle hysteresis. To glean further insights into the lengthmore »scale dependent asymmetric contact angle hysteresis, the contact lines formed by a nonvolatile room temperature ionic liquid placed onto the tilted pillar arrays were visualized and analyzed in situ in a scanning electron microscope. The ability to tune droplet directionality by merely changing the length scale of surface features all etched at the same tilt angle would be a versatile tool for manipulating multiphase flows and for selecting droplet directionality in other lap-on-chip applications.« less
A method for estimating the cooperativity length in polymers
Marco Pieruccini
2014-10-28
The problem of estimating the size of the cooperatively rearranging regions (CRRs) in supercooled polymeric melts from the analysis of the $\\alpha$-process in ordinary relaxation experiments is addressed. The system is treated with the canonical formalism as an ensemble of CRRs, which are described by a stationary distribution relative to the rearrangement energy threshold. The process whereby a CRR changes its configuration is viewed as consisting of two distinct steps: a reduced number of monomers reaches initially an activated state allowing for some local rearrangement; then, the regression of the energy fluctuation may take place through the configurational degrees of freedom, thus allowing for further rearrangements on larger length-scales. The latter are indeed those to which the well known Donth's scheme refers. Two main regimes are envisaged, depending on wether the role played by the configurational degrees of freedom in the regression of the energy fluctuation is significant or not. It is argued that the latter case is related to the occurrence of an arrhenian dependence of the central relaxation time. Data of the literature are rediscussed within this new framework.
Thermal management of long-length HTS cable systems
Demko, Jonathan A; Hassenzahl, William V
2011-01-01
Projections of electric power production suggest a major shift to renewables, such as wind and solar, which will be in remote locations where massive quantities of power are available. One solution for transmitting this power over long distances to load centers is direct current (dc), high temperature superconducting (HTS) cables. Electric transmission via dc cables promises to be effective because of the low-loss, highcurrent- carrying capability of HTS wire at cryogenic temperatures. However, the thermal management system for the cable must be carefully designed to achieve reliable and energyefficient operation. Here we extend the analysis of a superconducting dc cable concept proposed by the Electric Power Research Institute (EPRI), which has one stream of liquid nitrogen flowing in a cryogenic enclosure that includes the power cable, and a separate return tube for the nitrogen. Refrigeration stations positioned every 10 to 20 km cool both nitrogen streams. Both go and return lines are contained in a single vacuum/cryogenic envelope. Other coolants, including gaseous helium and gaseous hydrogen, could provide potential advantages, though they bring some technical challenges to the operation of long-length HTS dc cable systems. A discussion of the heat produced in superconducting cables and a system to remove the heat are discussed. Also, an analysis of the use of various cryogenic fluids in long-distance HTS power cables is presented.
Decreasing transmembrane segment length greatly decreases perfringolysin O pore size
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Lin, Qingqing; Li, Huilin; Wang, Tong; London, Erwin
2015-04-08
Perfringolysin O (PFO) is a transmembrane (TM) ?-barrel protein that inserts into mammalian cell membranes. Once inserted into membranes, PFO assembles into pore-forming oligomers containing 30–50 PFO monomers. These form a pore of up to 300 Ĺ, far exceeding the size of most other proteinaceous pores. In this study, we found that altering PFO TM segment length can alter the size of PFO pores. A PFO mutant with lengthened TM segments oligomerized to a similar extent as wild-type PFO, and exhibited pore-forming activity and a pore size very similar to wild-type PFO as measured by electron microscopy and a leakagemore »assay. In contrast, PFO with shortened TM segments exhibited a large reduction in pore-forming activity and pore size. This suggests that the interaction between TM segments can greatly affect the size of pores formed by TM ?-barrel proteins. PFO may be a promising candidate for engineering pore size for various applications.« less
Coherent neutron scattering and collective dynamics on mesoscale
Novikov, Vladimir [ORNL; Schweizer, Kenneth S [ORNL; Sokolov, Alexei P [ORNL
2013-01-01
By combining, and modestly extending, a variety of theoretical concepts for the dynamics of liquids in the supercooled regime, we formulate a simple analytic model for the temperature and wavevector dependent collective density fluctuation relaxation time that is measurable using coherent dynamic neutron scattering. Comparison with experiments on the ionic glass-forming liquid Ca K NO3 in the lightly supercooled regime suggests the model captures the key physics in both the local cage and mesoscopic regimes, including the unusual wavevector dependence of the collective structural relaxation time. The model is consistent with the idea that the decoupling between diffusion and viscosity is reflected in a different temperature dependence of the collective relaxation time at intermediate wavevectors and near the main (cage) peak of the static structure factor. More generally, our analysis provides support for the ideas that decoupling information and growing dynamic length scales can be at least qualitatively deduced by analyzing the collective relaxation time as a function of temperature and wavevector, and that there is a strong link between dynamic heterogeneity phenomena at the single and many particle level. Though very simple, the model can be applied to other systems, such as molecular liquids.
Spectra and Scattering of Light Lattice Nuclei from Effective Field Theory
Kirscher, Johannes; Gazit, Doron; Pederiva, Francesco; van Kolck, Ubirajara
2015-01-01
An effective field theory is used to describe light nuclei, calculated from quantum chromodynamics on a lattice at unphysically large pion masses. The theory is calibrated at leading order to two available data sets on two- and three-body nuclei for two pion masses. At those pion masses we predict the quartet and doublet neutron-deuteron scattering lengths, and the alpha-particle binding energy. For $m_\\pi=510~$MeV we obtain, respectively, $^4a_{\\rm nD}=2.3\\pm 1.3~$fm, $^2a_{\\rm nD}=2.2\\pm 2.1~$fm, and $B_{\\alpha}^{}=35\\pm 22~$MeV, while for $m_\\pi=805~$MeV $^4a_{\\rm nD}=1.6\\pm 1.3~$fm, $^2a_{\\rm nD}=0.62\\pm 1.0~$fm, and $B_{\\alpha}^{}=94\\pm 45~$MeV are found. Phillips- and Tjon-like correlations to the triton binding energy are established. Higher-order effects on the respective correlation bands are found insensitive to the pion mass. As a benchmark, we present results for the physical pion mass, using experimental two-body scattering lengths and the triton binding energy as input. Hints of subtle changes i...
Spectra and Scattering of Light Lattice Nuclei from Effective Field Theory
Johannes Kirscher; Nir Barnea; Doron Gazit; Francesco Pederiva; Ubirajara van Kolck
2015-06-30
An effective field theory is used to describe light nuclei, calculated from quantum chromodynamics on a lattice at unphysically large pion masses. The theory is calibrated at leading order to two available data sets on two- and three-body nuclei for two pion masses. At those pion masses we predict the quartet and doublet neutron-deuteron scattering lengths, and the alpha-particle binding energy. For $m_\\pi=510~$MeV we obtain, respectively, $^4a_{\\rm nD}=2.3\\pm 1.3~$fm, $^2a_{\\rm nD}=2.2\\pm 2.1~$fm, and $B_{\\alpha}^{}=35\\pm 22~$MeV, while for $m_\\pi=805~$MeV $^4a_{\\rm nD}=1.6\\pm 1.3~$fm, $^2a_{\\rm nD}=0.62\\pm 1.0~$fm, and $B_{\\alpha}^{}=94\\pm 45~$MeV are found. Phillips- and Tjon-like correlations to the triton binding energy are established. Higher-order effects on the respective correlation bands are found insensitive to the pion mass. As a benchmark, we present results for the physical pion mass, using experimental two-body scattering lengths and the triton binding energy as input. Hints of subtle changes in the structure of the triton and alpha particle are discussed.
Method for compression of data using single pass LZSS and run-length encoding
Berlin, G.J.
1994-01-01
A method used preferably with LZSS-based compression methods for compressing a stream of digital data. The method uses a run-length encoding scheme especially suited for data strings of identical data bytes having large run-lengths, such as data representing scanned images. The method reads an input data stream to determine the length of the data strings. Longer data strings are then encoded in one of two ways depending on the length of the string. For data strings having run-lengths less than 18 bytes, a cleared offset and the actual run-length are written to an output buffer and then a run byte is written to the output buffer. For data strings of 18 bytes or longer, a set offset and an encoded run-length are written to the output buffer and then a run byte is written to the output buffer. The encoded run-length is written in two parts obtained by dividing the run length by a factor of 255. The first of two parts of the encoded run-length is the quotient; the second part is the remainder. Data bytes that are not part of data strings of sufficient length are written directly to the output buffer.
Method for compression of data using single pass LZSS and run-length encoding
Berlin, G.J.
1997-12-23
A method used preferably with LZSS-based compression methods for compressing a stream of digital data is disclosed. The method uses a run-length encoding scheme especially suited for data strings of identical data bytes having large run-lengths, such as data representing scanned images. The method reads an input data stream to determine the length of the data strings. Longer data strings are then encoded in one of two ways depending on the length of the string. For data strings having run-lengths less than 18 bytes, a cleared offset and the actual run-length are written to an output buffer and then a run byte is written to the output buffer. For data strings of 18 bytes or longer, a set offset and an encoded run-length are written to the output buffer and then a run byte is written to the output buffer. The encoded run-length is written in two parts obtained by dividing the run length by a factor of 255. The first of two parts of the encoded run-length is the quotient; the second part is the remainder. Data bytes that are not part of data strings of sufficient length are written directly to the output buffer. 3 figs.
Method for compression of data using single pass LZSS and run-length encoding
Berlin, Gary J. (Beech Island, SC)
1997-01-01
A method used preferably with LZSS-based compression methods for compressing a stream of digital data. The method uses a run-length encoding scheme especially suited for data strings of identical data bytes having large run-lengths, such as data representing scanned images. The method reads an input data stream to determine the length of the data strings. Longer data strings are then encoded in one of two ways depending on the length of the string. For data strings having run-lengths less than 18 bytes, a cleared offset and the actual run-length are written to an output buffer and then a run byte is written to the output buffer. For data strings of 18 bytes or longer, a set offset and an encoded run-length are written to the output buffer and then a run byte is written to the output buffer. The encoded run-length is written in two parts obtained by dividing the run length by a factor of 255. The first of two parts of the encoded run-length is the quotient; the second part is the remainder. Data bytes that are not part of data strings of sufficient length are written directly to the output buffer.
Guo, Hao; Levin, K
2010-01-01
We show how the difference between the finite temperature T structure factors, called S_-, associated with spin and density, can be used as a indication of superfluidity in ultracold Fermi gases. This observation can be exploited in two photon Bragg scattering experiments on gases which undergo BCS- Bose Einstein condensation crossover. Essential to our calculations is a proper incorporation of spin and particle number conservation laws which lead to compatibility at general T with two f-sum rules. Because it is applicable to general scattering lengths, a measurement of S- can be a useful, direct approach for establishing where superfluidity occurs.
Inelastic electron-vortex-beam scattering
Ruben Van Boxem; Bart Partoens; Jo Verbeeck
2015-03-16
Recent theoretical and experimental developments in the field of electron vortex beam physics have raised questions on what exactly this novelty in the field of electron microscopy (and other fields, such as particle physics) really provides. An important part in the answer to those questions lies in scattering theory. The present investigation explores various aspects of inelastic quantum scattering theory for cylindrically symmetric beams with orbital angular momentum. The model system of Coulomb scattering on a hydrogen atom provides the setting to address various open questions: How is momentum transferred? Do vortex beams selectively excite atoms, and how can one employ vortex beams to detect magnetic transitions? The analytical approach presented here provides answers to these questions. OAM transfer is possible, but not through selective excitation; rather, by pre- and post-selection one can filter out the relevant contributions to a specific signal.
Scattering and; Delay, Scale, and Sum Migration
Lehman, S K
2011-07-06
How do we see? What is the mechanism? Consider standing in an open field on a clear sunny day. In the field are a yellow dog and a blue ball. From a wave-based remote sensing point of view the sun is a source of radiation. It is a broadband electromagnetic source which, for the purposes of this introduction, only the visible spectrum is considered (approximately 390 to 750 nanometers or 400 to 769 TeraHertz). The source emits an incident field into the known background environment which, for this example, is free space. The incident field propagates until it strikes an object or target, either the yellow dog or the blue ball. The interaction of the incident field with an object results in a scattered field. The scattered field arises from a mis-match between the background refractive index, considered to be unity, and the scattering object refractive index ('yellow' for the case of the dog, and 'blue' for the ball). This is also known as an impedance mis-match. The scattering objects are referred to as secondary sources of radiation, that radiation being the scattered field which propagates until it is measured by the two receivers known as 'eyes'. The eyes focus the measured scattered field to form images which are processed by the 'wetware' of the brain for detection, identification, and localization. When time series representations of the measured scattered field are available, the image forming focusing process can be mathematically modeled by delayed, scaled, and summed migration. This concept of optical propagation, scattering, and focusing have one-to-one equivalents in the acoustic realm. This document is intended to present the basic concepts of scalar scattering and migration used in wide band wave-based remote sensing and imaging. The terms beamforming and (delayed, scaled, and summed) migration are used interchangeably but are to be distinguished from the narrow band (frequency domain) beamforming to determine the direction of arrival of a signal, and seismic migration in which wide band time series are shifted but not to form images per se. Section 3 presents a mostly graphically-based motivation and summary of delay, scale, and sum beamforming. The model for incident field propagation in free space is derived in Section 4 under specific assumptions. General object scattering is derived in Section 5 and simplified under the Born approximation in Section 6. The model of this section serves as the basis in the derivation of time-domain migration. The Foldy-Lax, full point scatterer scattering, method is derived in Section 7. With the previous forward models in hand, delay, scale, and sum beamforming is derived in Section 8. Finally, proof-of-principle experiments are present in Section 9.
BUILDING A NETWORK FOR NEUTRON SCATTERING EDUCATION
Pynn, Roger; Baker, Shenda Mary; Louca, Despo A; McGreevy, Robert L; Ekkebus, Allen E; Kszos, Lynn A; Anderson, Ian S
2008-10-01
In a concerted effort supported by the National Science Foundation, the Department of Commerce, and the Department of Energy, the United States is rebuilding its leadership in neutron scattering capability through a significant investment in U.S. neutron scattering user facilities and related instrumentation. These unique facilities provide opportunities in neutron scattering to a broad community of researchers from academic institutions, federal laboratories, and industry. However, neutron scattering is often considered to be a tool for 'experts only' and in order for the U.S. research community to take full advantage of these new and powerful tools, a comprehensive education and outreach program must be developed. The workshop described below is the first step in developing a national program that takes full advantage of modern education methods and leverages the existing educational capacity at universities and national facilities. During March 27-28, 2008, a workshop entitled 'Building a Network for Neutron Scattering Education' was held in Washington, D.C. The goal of the workshop was to define and design a roadmap for a comprehensive neutron scattering education program in the United States. Successful implementation of the roadmap will maximize the national intellectual capital in neutron sciences and will increase the sophistication of research questions addressed by neutron scattering at the nation's forefront facilities. (See Appendix A for the list of attendees, Appendix B for the workshop agenda, Appendix C for a list of references. Appendix D contains the results of a survey given at the workshop; Appendix E contains summaries of the contributed talks.) The workshop brought together U.S. academicians, representatives from neutron sources, scientists who have developed nontraditional educational programs, educational specialists, and managers from government agencies to create a national structure for providing ongoing neutron scattering education. A concerted effort was made to involve representatives from historically black colleges and universities (HBCUs) and minority educational institutions (MEIs). The roadmap contained herein provides the path to a national infrastructure for education of students, faculty, and professional researchers who wish to make use of national neutron scattering facilities but do not have (or do not believe they have) the educational background to do so. Education of other stakeholders, including the public, students in kindergarten through twelfth grade (K-12), and policy makers is also included. The opening sessions of the workshop provided the current status of neutron scattering education in North America, Europe, and Australia. National neutron sources have individually developed outreach and advertising programs aimed at increasing awareness among researchers of the potential applications of neutron scattering. However, because their principal mission is to carry out scientific research, their outreach efforts are necessarily self-limiting. The opening session was designed to build awareness that the individual programs need to be coupled with, and integrated into, a broader education program that addresses the complete range of experience, from the student to the experienced researcher, and the wide range of scientific disciplines covered by neutron scattering. Such a program must also take full advantage of existing educational programs and expertise at universities and expand them using modern distance learning capabilities, recognizing that the landscape of education is changing.
J. E. Beckman; R. F. Peletier; J. H. Knapen; R. L. M. Corradi; L. J. Gentet
1996-02-19
We have measured the radial brightness distributions in the disks of three nearby face-on spirals: M 51, NGC 3631, and NGC 4321 (M 100) in the photometric bands B through I, with the addition of the K band for M 51 only. The measurements were made by averaging azimuthally, in three modes, the two-dimensional surface brightness over the disks in photometric images of the objects in each band: (a) over each disk as a whole, (b) over the spiral arms alone, and (c) over the interarm zones alone. From these profiles scale-lengths were derived for comparison with schematic exponential disk models incorporating interstellar dust. These models include both absorption and scattering in their treatment of radiative transfer. The model fits show that the arms exhibit greater optical depth in dust than the interarm zones. The average fraction of emitted stellar light in V which is extinguished by dust within 3 scale-lengths of the center of each galaxy does not rise above 20% in any of them. We show that this conclusion is also valid for models with similar overall quantities of dust, but where this is concentrated in lanes. These can also account for the observed scale-lengths, and their variations.
Recent Applications of Small-angle Neutron Scattering in Strongly Interacting Soft-condensed Matter
Wignall, George D [ORNL; Melnichenko, Yuri B [ORNL
2005-01-01
Before the application of small-angle neutron scattering (SANS) to the study of polymer structure, chain conformation studies were limited to light and small-angle x-ray scattering techniques, usually conducted in dilute solution owing to the difficulties of separating the inter- and intrachain contributions to the structure. The unique role of neutron scattering in soft condensed matter arises from the difference in the coherent scattering length between deuterium (b{sub D} = 0.67 x 10{sup -12} cm) and hydrogen (b{sub H} = -0.37 x 10{sup -12} cm), which results in a marked difference in scattering power (contrast) between molecules synthesized from normal (hydrogeneous) and deuterated monomer units. Thus, deuterium labelling techniques may be used to 'stain' molecules and make them 'visible' in the condensed state and other crowded environments, such as concentrated solutions of overlapping chains. For over two decades, SANS has proved to be a powerful tool for studies of structure-property relationships in polymeric systems and has made it possible to extract unique information about their size, shape, conformational changes and molecular associations. These applications are now so numerous that an exhaustive review of the field is no longer practical, so the authors propose to focus on the use of SANS for studies of strongly interacting soft matter systems. This paper will therefore discuss basic theory and practical aspects of the technique and will attempt to explain the physics of scattering with the minimum of unnecessary detail and mathematical rigour. Examples will be given to demonstrate the power of SANS and to show how it has helped to unveil universal aspects of the behaviour of macromolecules in such apparently diverse systems as polymer solutions, blends, polyelectrolytes and supercritical mixtures. The aim of the authors is to aid potential users who have a general scientific background, but no specialist knowledge of scattering, to understand the potential of the technique and, if they so choose, to apply it to provide new information in areas of their own particular research interests.
Cross-Section Fluctuations in Chaotic Scattering
B. Dietz; H. L. Harney; A. Richter; F. Schaefer; H. A. Weidenmueller
2009-12-22
For the theoretical prediction of cross-section fluctuations in chaotic scattering, the cross-section autocorrelation function is needed. That function is not known analytically. Using experimental data and numerical simulations, we show that an analytical approximation to the cross-section autocorrelation function can be obtained with the help of expressions first derived by Davis and Boose. Given the values of the average S-matrix elements and the mean level density of the scattering system, one can then reliably predict cross-section fluctuations.
Account of Nuclear Scattering at Volume Reflection
Bondarenco, M V
2011-01-01
For a particle traversing a bent crystal in the regime of volume reflection we evaluate the probability of interaction with atomic nuclei. Regardless of the continuous potential shape, this probability is found to differ from the corresponding value in an amorphous target by an amount proportional to the crystal bending radius, and the particle deflection angle. Based on this result, we evaluate the rate of inelastic nuclear interactions, and the final beam angular dispersion due to multiple Coulomb scattering. The theoretical predictions are compared with the experiments. The impact of multiple Coulomb scattering on the mean volume reflection angle is also discussed.
Rayleigh-Brillouin scattering of carbon dioxide
Gu, Ziyu; van de Water, Willem
2014-01-01
The spectral lineshape of spontaneous Rayleigh-Brillouin scattering in CO2 is studied in a range of pressures. The spectrum is influenced by the bulk viscosity, which is a relaxation phenomenon involving the internal degrees of freedom of the molecule. The associated relaxation rates can be compared to the frequency shift of the scattered light, which demands precise measurements of the spectral lineshape. We find the value of the bulk viscosity around 5.7 X 10^{-6} kg/(ms) for the range of pressures p= 2-4 bar and for conditions of room temperature.
High Energy Scattering in Higher Dimensional Theories
Maharana, Jnanadeva
2015-01-01
The high energy behavior of scattering amplitudes in spacetime dimensions, $D>4$, is investigated. The bound on total cross sections, $\\sigma_t \\le Constant~(los s)^{D-2}$, $D\\ge 4$ has been obtained in the past under usual assumptions. I derive new bound on scattering amplitudes in the region $|t|
A. Liam Fitzpatrick; Jared Kaplan
2011-04-13
We show that suitably regulated multi-trace primary states in large N CFTs behave like `in' and `out' scattering states in the flat-space limit of AdS. Their transition matrix elements approach the exact scattering amplitudes for the bulk theory, providing a natural CFT definition of the flat space S-Matrix. We study corrections resulting from the AdS curvature and particle propagation far from the center of AdS, and show that AdS simply provides an IR regulator that disappears in the flat space limit.
[Inelastic electron scattering from surfaces]. [Progress report
Not Available
1993-10-01
This program uses ab-initio and multiple scattering to study surface dynamical processes; high-resolution electron-energy loss spectroscopy is used in particular. Off-specular excitation cross sections are much larger if electron energies are in the LEED range (50--300 eV). The analyses have been extended to surfaces of ordered alloys. Phonon eigenvectors and eigenfrequencies were used as inputs to electron-energy-loss multiple scattering cross section calculations. Work on low-energy electron and positron holography is mentioned.
Scattering theory with localized non-Hermiticities
Znojil, Miloslav [Nuclear Physics Institute ASCR, 250 68 Rez (Czech Republic)
2008-07-15
In the context of the recent interest in solvable models of scattering mediated by non-Hermitian Hamiltonians (cf. H. F. Jones, Phys. Rev. D 76, 125003 (2007)) we show that the well-known variability of the ad hoc choice of the metric {theta} which defines the physical Hilbert space of states can help us to clarify several apparent paradoxes. We argue that with a suitable {theta}, a fully plausible physical picture of the scattering can be recovered. Quantitatively, our new recipe is illustrated on an exactly solvable toy model.
Geometric phases in a scattering process
Liu, H. D.; Yi, X. X. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)
2011-08-15
The study of geometric phase in quantum mechanics has so far been confined to discrete (or continuous) spectra and trace-preserving evolutions. By considering only the transmission channel, a scattering process with internal degrees of freedom is neither a discrete spectrum problem nor a trace-preserving process. We explore the geometric phase in the scattering process by taking only the transmission process into account. We find that the geometric phase can be calculated by the same method as in unitary evolution. The interference visibility depends on the transmission amplitude. The dependence of the geometric phase on the barrier strength and the spin-spin coupling constant is also presented and discussed.
Diffractive Scattering and Gauge/String Duality
Tan, Chung-I [Brown University, Providence, Rhode Island, United States
2009-09-01
High-energy diffractive scattering will be discussed based on Gauge/String duality. As shown by Brower, Polchinski, Strassler and Tan, the ubiquitous Pomeron emerges naturally in gauge theories with string-theoretical descriptions. Its existence is intimately tied to gluons, and also to the energy-momentum tensor. With a confining dual background metric, the Pomeron can be interpreted as a 'massive graviton'. In a single unified step, both its infrared and ultraviolet properties are dealt with, reflecting confinement and conformal symmetry respectively. An effective field theory for high-energy scattering can be constructed. Applications based on this approach will also be described.
Electromagnetic wave scattering by small bodies
A. G. Ramm
2008-04-21
A reduction of the Maxwell's system to a Fredholm second-kind integral equation with weakly singular kernel is given for electromagnetic (EM) wave scattering by one and many small bodies. This equation is solved asymptotically as the characteristic size of the bodies tends to zero. The technique developed is used for solving the many-body EM wave scattering problem by rigorously reducing it to solving linear algebraic systems, completely bypassing the usage of integral equations. An equation is derived for the effective field in the medium, in which many small particles are embedded. A method for creating a desired refraction coefficient is outlined.
Quantum-entanglement-initiated super Raman scattering
Agarwal, G. S. [Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078 (United States)
2011-02-15
It has now been possible to prepare a chain of ions in an entangled state and thus the question arises: How will the optical properties of a chain of entangled ions differ from say a chain of independent particles? We investigate nonlinear optical processes in such chains. Since light scattering is quite a versatile technique to probe matter, we explicitly demonstrate the possibility of entanglement-produced super Raman scattering. Our results suggest the possibility of similar enhancement factors in other nonlinear processes like four-wave mixing.
Alpha resonant scattering for astrophysical reaction studies
Yamaguchi, H.; Kahl, D.; Nakao, T. [Center for Nuclear Study (CNS), University of Tokyo, RIKEN campus, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Wakabayashi, Y.; Kubano, S. [The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Hashimoto, T. [Research Center for Nuclear Physics (RCNP), Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Hayakawa, S. [Istituto Nazionale Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS), Via S. Sofia 62, 95125 Catania (Italy); Kawabata, T. [Department of Physics, Kyoto University, Kita-Shirakawa, Kyoto 606-8502 (Japan); Iwasa, N. [Department of Physics, Tohoku University, Aoba, Sendai, Miyagi 980-8578 (Japan); Teranishi, T. [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan); Kwon, Y. K. [Institute for Basic Science, 70, Yuseong-daero 1689-gil, Yuseong-gu, Daejeon 305-811 (Korea, Republic of); Binh, D. N. [30 MeV Cyclotron Center, Tran Hung Dao Hospital, Hoan Kiem District, Hanoi (Viet Nam); Khiem, L. H.; Duy, N. G. [Institute of Physics, Vietnam Academy of Science and Technology, 18 Hong Quoc Viet, Nghia do, Hanoi (Viet Nam)
2014-05-02
Several alpha-induced astrophysical reactions have been studied at CRIB (CNS Radioactive Ion Beam separator), which is a low-energy RI beam separator at Center for Nuclear Study (CNS) of the University of Tokyo. One of the methods to study them is the ? resonant scattering using the thick-target method in inverse kinematics. Among the recent studies at CRIB, the measurement of {sup 7}Be+? resonant scattering is discussed. Based on the result of the experiment, we evaluated the contributions of high-lying resonances for the {sup 7}Be(?,?) reaction, and proposed a new cluster band in {sup 11}C.
Quantum Electric Field Fluctuations and Potential Scattering
Haiyun Huang; L. H. Ford
2015-03-10
Some physical effects of time averaged quantum electric field fluctuations are discussed. The one loop radiative correction to potential scattering are approximately derived from simple arguments which invoke vacuum electric field fluctuations. For both above barrier scattering and quantum tunneling, this effect increases the transmission probability. It is argued that the shape of the potential determines a sampling function for the time averaging of the quantum electric field operator. We also suggest that there is a nonperturbative enhancement of the transmission probability which can be inferred from the probability distribution for time averaged electric field fluctuations.
Quantum Electric Field Fluctuations and Potential Scattering
Huang, Haiyun
2015-01-01
Some physical effects of time averaged quantum electric field fluctuations are discussed. The one loop radiative correction to potential scattering are approximately derived from simple arguments which invoke vacuum electric field fluctuations. For both above barrier scattering and quantum tunneling, this effect increases the transmission probability. It is argued that the shape of the potential determines a sampling function for the time averaging of the quantum electric field operator. We also suggest that there is a nonperturbative enhancement of the transmission probability which can be inferred from the probability distribution for time averaged electric field fluctuations.
Noise autocorrelation spectroscopy with coherent Raman scattering
Loss, Daniel
LETTERS Noise autocorrelation spectroscopy with coherent Raman scattering XIAOJI G. XU, STANISLAV O to noise. Here, we present a new approach to coherent Raman spectroscopy in which high resolution is achieved by means of deliberately introduced noise. The proposed method combines the efficiency
Coherent anti-Stokes Raman Scattering (CARS)
Greenaway, Alan
Coherent anti-Stokes Raman Scattering (CARS) For the study of biofilms Alexander Mc Vey1, Nils.f.mcvey@ed.ac.uk Polystyrene beads of diameter 2µm as imaged by the CARS system at COSMIC, The University of Edinburgh #12;Introduction Outline of CARS CARS set-up Results Pushing the limits Results Imaging E. coli Where do we go
Wave scattering and splitting by magnetic metamaterials
Wave scattering and splitting by magnetic metamaterials Alexander B. Kozyrev1, Chao Qin1, Ilya V experimentally propagation of electromagnetic waves through a slab of uniaxial magnetic metamaterial. We observe.2110) Electromagnetic Theory; (999.9999) Metamaterials. References and links 1. D. R. Smith, W. J. Padilla, D. C. Vier
Scattering theory of electrical Markus Bttiker
Paris-Sud 11, Université de
symmetry H-invariant if momenta and magnetic field are reversed 13 but is an even function incident current density density of states independent of material !! 6 Landauer formula #12;Drift state scattering matrix current conservation S is a unitray matrix In the absence of a magnetic field
Millstone Hill Thomson Scatter Results for 1971
Evans, J. V.
1978-03-24
During 1971, the incoherent scatter radar at Millstone Hill (42.6°N, 71.5°W) was employed to measure the electron density, electron and ion temperatures, and the vertical velocity of the 0[superscript +] ions in the F-region ...
INVERSE SCATTERING PROBLEMS WITH MULTI-FREQUENCIES ...
2015-01-25
as location, geometry, or material property, from knowledge of the scattered field ... samples), and nano-optics (e.g., design and fabrication of nano-scale optical ... cated structures, and to accurately compute acoustic and electromagnetic fields and ...... sion method for 3D electromagnetic imaging using adjoint fields, Inverse
The Kinematic Algebras from the Scattering Equations
Monteiro, Ricardo
2013-01-01
We study kinematic algebras associated to the recently proposed scattering equations, which arise in the description of the scattering of massless particles. In particular, we describe the role that these algebras play in the BCJ duality between colour and kinematics in gauge theory, and its relation to gravity. We find that the scattering equations are a consistency condition for a self-dual-type vertex which is associated to each solution of those equations. We also identify an extension of the anti-self-dual vertex, such that the two vertices are not conjugate in general. Both vertices correspond to the structure constants of Lie algebras. We give a prescription for the use of the generators of these Lie algebras in trivalent graphs that leads to a natural set of BCJ numerators. In particular, we write BCJ numerators for each contribution to the amplitude associated to a solution of the scattering equations. This leads to a decomposition of the determinant of a certain kinematic matrix, which appears natur...
Scattering of twisted relativistic electrons by atoms
V. Serbo; I. P. Ivanov; S. Fritzsche; D. Seipt; A. Surzhykov
2015-05-11
The Mott scattering of high-energetic twisted electrons by atoms is investigated within the framework of the first Born approximation and Dirac's relativistic equation. Special emphasis is placed on the angular distribution and longitudinal polarization of the scattered electrons. In order to evaluate these angular and polarization properties we consider two experimental setups in which the twisted electron beam collides with either a single well-localized atom or macroscopic atomic target. Detailed relativistic calculations have been performed for both setups and for the electrons with kinetic energy from 10 keV to 1000 keV. The results of these calculations indicate that the emission pattern and polarization of outgoing electrons differ significantly from the scattering of plane-wave electrons and can be very sensitive to the parameters of the incident twisted beam. In particular, it is shown that the angular- and polarization-sensitive Mott measurements may reveal valuable information about, both the transverse and longitudinal components of the linear momentum and the projection of the total angular momentum of twisted electron states. Thus, the Mott scattering emerges as a diagnostic tool for the relativistic vortex beams.
Geometry of Scattering at Planckian Energies
Renata Kallosh
1991-11-05
We present an alternative derivation and geometrical formulation of Verlinde topological field theory, which may describe scattering at center of mass energies comparable or larger than the Planck energy. A consistent trunckation of 3+1 dimensional Einstein action is performed using the standard geometrical objects, like tetrads and spin connections. The resulting topological invariant is given in terms of differential forms.
NONLINEAR EFFECTS IN WAVE SCATTERING AND GENERATION
NONLINEAR EFFECTS IN WAVE SCATTERING AND GENERATION Flow Interaction with Topography Roger Grimshaw for waves to be generated upstream and/or downstream. In many cases when the topographic feature has a small, the initial condition for the fKdV equation is u(x 0) = 0 so that the waves are generated directly by the ow
Kaonic Hydrogen and K p Scattering
Weise, Wolfram
Kaonic Hydrogen and KĂż p Scattering B. Borasoy,1,2,* R. NiĂ?ler,1,2, and W. Weise1, 1 Physik and width in kaonic hydrogen in view of the new accurate DEAR measurements. Questions of consistency
Fiber optic probe for light scattering measurements
Nave, Stanley E. (Evans, GA); Livingston, Ronald R. (Aiken, SC); Prather, William S. (Augusta, GA)
1995-01-01
A fiber optic probe and a method for using the probe for light scattering analyses of a sample. The probe includes a probe body with an inlet for admitting a sample into an interior sample chamber, a first optical fiber for transmitting light from a source into the chamber, and a second optical fiber for transmitting light to a detector such as a spectrophotometer. The interior surface of the probe carries a coating that substantially prevents non-scattered light from reaching the second fiber. The probe is placed in a region where the presence and concentration of an analyte of interest are to be detected, and a sample is admitted into the chamber. Exciting light is transmitted into the sample chamber by the first fiber, where the light interacts with the sample to produce Raman-scattered light. At least some of the Raman-scattered light is received by the second fiber and transmitted to the detector for analysis. Two Raman spectra are measured, at different pressures. The first spectrum is subtracted from the second to remove background effects, and the resulting sample Raman spectrum is compared to a set of stored library spectra to determine the presence and concentration of the analyte.
Fiber optic probe for light scattering measurements
Nave, S.E.; Livingston, R.R.; Prather, W.S.
1993-01-01
This invention is comprised of a fiber optic probe and a method for using the probe for light scattering analyses of a sample. The probe includes a probe body with an inlet for admitting a sample into an interior sample chamber, a first optical fiber for transmitting light from a source into the chamber, and a second optical fiber for transmitting light to a detector such as a spectrophotometer. The interior surface of the probe carries a coating that substantially prevents non-scattered light from reaching the second fiber. The probe is placed in a region where the presence and concentration of an analyte of interest are to be detected, and a sample is admitted into the chamber. Exciting light is transmitted into the sample chamber by the first fiber, where the light interacts with the sample to produce Raman-scattered light. At least some of the Raman- scattered light is received by the second fiber and transmitted to the detector for analysis. Two Raman spectra are measured, at different pressures. The first spectrum is subtracted from the second to remove background effects, and the resulting sample Raman spectrum is compared to a set of stored library spectra to determine the presence and concentration of the analyte.
Inelastic neutron scattering in valence fluctuation compounds
Jon M Lawrence
2011-02-15
The valence fluctuation compounds are rare earth intermetallics where hybridization of the nearly-localized 4f electrons with the conduction electrons leads to incorporation of the 4f's into the itinerant states. This hybridization slows down the conduction electrons and hence gives them a heavy effective mass, justifying application of the term 'heavy Fermion' (HF) to these materials. During the project period, we grew large single crystals of several such compounds and measured their properties using both standard thermodynamic probes and state-of-the-art inelastic neutron scattering. We obtained three main results. For the intermediate valence compounds CePd{sub 3} and YbAl{sub 3}, we showed that the scattering of neutrons by the fluctuations of the 4f magnetic moment does not have the momentum dependence expected for the itinerant heavy mass state; rather, the scattering is more typical of a localized spin fluctuation. We believe that incoherent scattering localizes the excitation. For the heavy Fermion compound Ce(Ni{sub 0.935}Pd{sub 0.065}){sub 2}Ge{sub 2}, which sits at a T = 0 critical point for transformation into an antiferromagnetic (AF) phase, we showed that the scattering from the AF fluctuations does not exhibit any of the divergences that are expected at a phase transition. We speculate that alloy disorder profoundly suppresses the growth of the fluctuating AF regions, leading to short range clusters rather than regions of infinite size. Finally, we explored the applicability of key concepts used to describe the behavior of rare earth heavy Fermions to uranium based HF compounds where the 5f electrons are itinerant as opposed to localized. We found that scaling laws relating the spin fluctuation energy measured in neutron scattering to the low temperature specific heat and susceptibility are valid for the uranium compounds, once corrections are made for AF fluctuations; however, the degeneracy of the high temperature moment is smaller than expected for rare-earth-like Hund's rule behavior, essentially because the orbital moment is suppressed for itinerant 5f electrons. We also found that the standard local-moment-based theory of the temperature dependence of the specific heat, susceptibility and neutron scattering fails badly for URu{sub 2}Zn{sub 20} and UCo{sub 2}Zn{sub 20}, even though the theory is phenomenally successful for the closely related rare earth compound YbFe{sub 2}Zn{sub 20}. Both these results highlight the distinction between the itineracy of the 5f's and the localization of the 4f's. It is our hope that these results are sufficiently significant as to stimulate deeper investigation of these compounds.
Simulation of a D-T Neutron Source for Neutron Scattering Experiments
Lou, T.P.; Ludewigt, B.A.; Vujic, J.L.; Leung, K.-N.
2003-01-01
T Neutron Source for Neutron Scattering Experiments T.P. Louor cold neutrons for neutron scattering experiments. Thisto simulate a neutron scattering setup and to estimate
Nano-crystal growth in cordierite glass ceramics studied with X-ray scattering
Bras, Wim
2010-01-01
By Small-Angle Neutron-Scattering, Electron-Paramagneticphases.. Small angle neutron scattering (SANS) experimentsand Small Angle Neutron Scattering (SANS) on some of the
Page, John
the solid scatterers, and by ii tortuosity effects, where the wave energy is largely confined University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Received 4 June 1998 We study, both
Coherent light scattering of ultraviolet light by avian feather barbs
Prum, Richard O.; Andersson, Staffan; Torres, Rodolfo H.
2003-04-05
Ultraviolet (UV) structural colors of avian feathers are produced by the spongy medullary keratin of feather barbs, but various physical mechanisms have been hypothesized to produce those colors, including Rayleigh scattering, Mie scattering...
Fluid Flow Property Estimation from Seismic Scattering Data
Brown, Stephen
2012-01-01
We present a methodology for relating seismic scattering signals from fractures to the fluid permeability field of the fracture network. The workflow is used to interpret seismic scattering signals for the reservoir ...
Multidimensional Inverse Scattering with Fixed-Energy Data
Multidimensional Inverse Scattering with Fixed-Energy Data A.G. Ramm Department of Mathematics #12;Multidimensional Inverse Scattering with Fixed-Energy Data 375 0 =/8o p(x)wl(x)w2(x)da'. (**) J
A study of neutron-deuteron scattering in configuration space
V. M. Suslov; M. A. Braun; I. Filikhin; B. Vlahovic
2006-10-09
A new computational method for solving the configuration-space Faddeev equations for the breakup scattering problem has been applied to nd scattering both below and above the two-body threshold.
Anisotropic light scattering of individual sickle red blood cells
Kim, Youngchan
We present the anisotropic light scattering of individual red blood cells (RBCs) from a patient with sickle cell disease (SCD). To measure light scattering spectra along two independent axes of elongated-shaped sickle RBCs ...
Radicle length and osmotic stress affect the chilling sensitivity of cucumber radicles
Mangrich, M E; Martinez-Font, R T; Saltveit, Mikal E
2006-01-01
seedling vigor, and induced osmotic- and heat-shock pro-2006 Radicle Length and Osmotic Stress Affect the Chillingmm before and after the osmotic treatment, after chilling,
Anovitz, Lawrence {Larry} M [ORNL; Cole, David [Ohio State University; Rother, Gernot [ORNL; Allard Jr, Lawrence Frederick [ORNL; Jackson, Andrew [NIST Center for Neutron Research (NCRN), Gaithersburg, MD; Littrell, Ken [ORNL
2013-01-01
Small- and Ultra-Small Angle Neutron Scattering (SANS and USANS) provide powerful tools for quantitative analysis of porous rocks, yielding bulk statistical information over a wide range of length scales. This study utilized (U)SANS to characterize shallowly buried quartz arenites from the St. Peter Sandstone. Backscattered electron imaging was also used to extend the data to larger scales. These samples contain significant volumes of large-scale porosity, modified by quartz overgrowths, and neutron scattering results show significant sub-micron porosity. While previous scattering data from sandstones suggest scattering is dominated by surface fractal behavior over many orders of magnitude, careful analysis of our data shows both fractal and pseudo-fractal behavior. The scattering curves are composed of subtle steps, modeled as polydispersed assemblages of pores with log-normal distributions. However, in some samples an additional surface-fractal overprint is present, while in others there is no such structure, and scattering can be explained by summation of non-fractal structures. Combined with our work on other rock-types, these data suggest that microporosity is more prevalent, and may play a much more important role than previously thought in fluid/rock interactions.
Proton-Proton Scattering at 340 MeV
Chamberlain, Owen; Wiegand, Clyde
2008-01-01
shielding and due to the strong diffraction scattering in the forvrard direction by carbon in the polyethylene
Small Angle X-ray Scattering (SAXS) Laboratory Learning Experiences
Meagher, Mary
.A. & Svergun D.I. (1987). Structure Analysis by Small-Angle X-Ray and Neutron Scattering. NY: Plenum PressSmall Angle X-ray Scattering (SAXS) Laboratory Learning Experiences o - Use of small angle X-ray scattering instrumentation o - Programs that you will use SAXS (BRUKER AXS) PRIMUS (Konarev, Volkov, Koch
MULTIPLICITY OF RESONANCES EQUALS MULTIPLICITY OF THE SCATTERING MATRIX
); #31;(x) = ~ #31;(x) = 1; ~ #31;#31; = #31;: ? Supported in part by ACI : M#19;ethodes math#19 matrix is de#12;ned just as in the usual potential scattering [4], [3]. We denote by S(#21;) the standard (relative) scattering matrix. The standard scattering matrix S(#21;) continues meromorphically in #21; from
Nitrogen Contamination in Elastic Neutron Scattering Songxue Chi,ab
Lynn, Jeffrey W.
Nitrogen Contamination in Elastic Neutron Scattering Songxue Chi,ab Jeffrey W. Lynn,a* Ying Chen a neutron scattering measurement is a contribution to the background, especially in inelastic measurements of having N2 in the sample environment system during elastic neutron scattering measurements on a single
The Neutron Scattering Society www.neutronscattering.org
Chen, Sow-Hsin
The Neutron Scattering Society of America www.neutronscattering.org Press Release, February 4, 2008 The Neutron Scattering Society of America is pleased to announce the 2008 recipients of its 3 major prizes. The Neutron Scattering Society of America (NSSA) established the Clifford G. Shull Prize in Neutron Science
Coulomb scattering for scalar field in Scr\\" odinger picture
Crucean Cosmin; Racoceanu Radu; Pop Adrian
2008-04-11
The scattering of a charged scalar field on Coulomb potential on de Sitter space-time is studied using the solution of the free Klein-Gordon equation. We find that the scattering amplitude is independent of the choice of the picture and in addition the total energy is conserved in the scattering process.
National School on Neutron and X-ray Scattering
15th National School on Neutron and X-ray Scattering August 10 - 24, 2013 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major Ridge National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang
Thirteenth National School on Neutron and X-ray Scattering
Thirteenth National School on Neutron and X-ray Scattering June 11 June 25, 2011 at Argonne of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang, Suzanne
Neutron scattering in magnetic fields (*) W. C. Koehler
Boyer, Edmond
691 Neutron scattering in magnetic fields (*) W. C. Koehler Solid State Division, Oak Ridge. Abstract 2014 The use of magnetic fields in neutron scattering experimentation is reviewed briefly. Two of the scattering sample ; in the second the field acts on the neutron itself. Several examples are discussed
Sixteenth National School on Neutron and X-ray Scattering
Pennycook, Steve
Sixteenth National School on Neutron and X-ray Scattering June 14-28, 2014 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major's Neutron Scattering Science Division. Scientific Directors: Suzanne G.E. te Velthuis, Esen Ercan Alp
The Neutron Scattering Society www.neutronscattering.org
Homes, Christopher C.
The Neutron Scattering Society of America www.neutronscattering.org Press Release February 11, 2008 The Neutron Scattering Society of America is pleased to announce the election as Fellows of the Society of in application of neutron scattering to studies of surfaces and crystal field excitations as well as his
National School on Neutron and X-ray Scattering
Pennycook, Steve
National School on Neutron and X-ray Scattering May 30 June 13, 2009 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang, Suzanne
Fourteenth National School on Neutron and X-ray Scattering
Pennycook, Steve
Fourteenth National School on Neutron and X-ray Scattering August 12 - 25, 2012 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major Ridge National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang
Neutron Scattering Society of America Purpose and New Initiatives
1 Neutron Scattering Society of America (NSSA) Purpose and New Initiatives www.neutronscattering.org SNS/ANL School on Neutron and X-Ray Scattering June 2011 Visit us now on Facebook #12;2 What and provide a focal point for the neutron scattering community in the USA To identify the needs
A Java-based Science Portal for Neutron Scattering Experiments
Vazhkudai, Sudharshan
A Java-based Science Portal for Neutron Scattering Experiments Sudharshan S. Vazhkudai James A scattering facility recently commissioned by the US Department of Energy (DOE). The neutron beam produced (SNS) [14] is a large-scale leading- edge neutron scattering facility that hopes to fundamen- tally
TUTORIAL / ARTICLE DIDACTIQUE Neutron scattering study of the classical
Ryan, Dominic
TUTORIAL / ARTICLE DIDACTIQUE Neutron scattering study of the classical antiferromagnet MnF2: a perfect hands-on neutron scattering teaching course1 Z. Yamani, Z. Tun, and D.H. Ryan Abstract: We present of neutron scattering concepts. The nature of antiferromagnetism and the magnetic Hamiltonian in this classi
ORNL Neutron Scattering School May 30 -June 5, 2009
Pennycook, Steve
ORNL Neutron Scattering School May 30 - June 5, 2009 Oak Ridge National Laboratory Oak Ridge, 2009, for the first week of the Neutron Xray Scattering School. Please be certain to bring photo for Neutron Scattering Users · Radiological Worker Training for HFIR and SNS Users In addition
Twelfth National School on Neutron and X-ray Scattering
Pennycook, Steve
Twelfth National School on Neutron and X-ray Scattering June 12 June 26, 2010 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang, Suzanne
LANSCE School on Neutron Scattering: Materials at the Mesoscale
1 11th LANSCE School on Neutron Scattering: Materials at the Mesoscale Lujan Center Los Alamos. Please name the applicant for admission to the 11th LANSCE School on Neutron Scattering: Last, First LANSCE School on Neutron Scattering including: drive and motivation, ability to work with others
Tenth National School on Neutron and X-ray Scattering
Pennycook, Steve
Tenth National School on Neutron and X-ray Scattering September 24 - October 11, 2008 at Argonne of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang, Suzanne
Neutron Scattering Society of America Purpose and New Initiatives
Pennycook, Steve
1 Neutron Scattering Society of America (NSSA) Purpose and New Initiatives www.neutronscattering.org SNS/ANL School on Neutron and X-Ray Scattering June 2010 Visit us now on Facebook #12;2 What and provide a focal point for the neutron scattering community in the USA To identify the needs
Nonperturbative NN scattering in {sup 3}S{sub 1}–{sup 3}D{sub 1} channels of EFT(??)
Yang, Ji-Feng
2013-12-15
The closed-form T matrices in the {sup 3}S{sub 1}–{sup 3}D{sub 1} channels of EFT(??) for NN scattering with the potentials truncated at order O(Q{sup 4}) are presented with the nonperturbative divergences parametrized in a general manner. The stringent constraints imposed by the closed form of the T matrices are exploited in the underlying theory perspective and turned into virtues in the implementation of subtractions and the manifestation of power counting rules in nonperturbative regimes, leading us to the concept of EFT scenario. A number of scenarios of the EFT description of NN scattering are compared with PSA data in terms of effective range expansion and {sup 3}S{sub 1} phase shifts, showing that it is favorable to proceed in a scenario with conventional EFT couplings and sophisticated renormalization in order to have large NN scattering lengths. The informative utilities of fine tuning are demonstrated in several examples and naturally interpreted in the underlying theory perspective. In addition, some of the approaches adopted in the recent literature are also addressed in the light of EFT scenario. -- Highlights: •Closed-form unitary T matrices for NN scattering are obtained in EFT(??). •Nonperturbative properties inherent in such closed-form T matrices are explored. •Nonperturbative renormalization is implemented through exploiting these properties. •Unconventional power counting of couplings is shown to be less favored by PSA data. •The ideas about nonperturbative renormalization here might have wider applications.
Bahadur, J. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)], E-mail: jbahadur@barc.gov.in; Sen, D.; Mazumder, S. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Ramanathan, S. [Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)
2008-05-15
Nano-crystalline nickel oxide powder was synthesized by a precipitation route. Powder samples were heat treated at 300, 600 and 900 deg. C, and pore structure evolution was followed by small angle neutron scattering (SANS) technique. SANS measurements were carried out also on pelleted samples in order to study the modifications of pore morphology due to heat treatment. SANS data reveal scattering from pores at two different length scales. The pore structure at various heat treatment temperatures does not follow any scaling behavior. - Graphical abstract: SEM micrograph shows the microstructure of the nano-crystalline NiO. An average agglomerate size of {approx}1 {mu}m is evident from SEM and LS. SANS profiles for the samples heat treated at 300, 600 and 900 deg. C, respectively, are shown. A significant variation in the profile shape due to the modification in the intra-agglomerate pore structure under heat treatment is visible.
Ying Chen; Ming Gong; Yu-Hong Lei; Ning Li; Jian Liang; Chuan Liu; Jin-Long Liu; Yong-Fu Liu; Yu-Bin Liu; Zhaofeng Liu; Jian-Ping Ma; Zhan-Lin Wang; Jian-Bo Zhang
2015-03-09
In this paper, low-energy scattering of the $(D^{*}\\bar{D}^{*})^\\pm$ meson system is studied within L\\"uscher's finite-size formalism using $N_{f}=2$ twisted mass gauge field configurations. With three different pion mass values, the $s$-wave threshold scattering parameters, namely the scattering length $a_0$ and the effective range $r_0$, are extracted in $J^P=1^+$ channel. Our results indicate that, in this particular channel, the interaction between the two vector charmed mesons is weakly repulsive in nature hence do not support the possibility of a shallow bound state for the two mesons, at least for the pion mass values being studied. This study provides some useful information on the nature of the newly discovered resonance-like structure $Z_c(4025)$ observed in various experiments.
Double pulse Thomson scattering system at RTP
Beurskens, M.N.; Barth, C.J.; Chu, C.C.; Donne, A.J.; Herranz, J.A.; Lopes Cardozo, N.J.; van der Meiden, H.J.; Pijper, F.J. [FOM-Instituut voor Plasmafysica `Rijnhuizen`, Associatie Euratom-FOM, 3430 BE Nieuwegein (The Netherlands)] [FOM-Instituut voor Plasmafysica `Rijnhuizen`, Associatie Euratom-FOM, 3430 BE Nieuwegein (The Netherlands)
1997-01-01
In this article a double pulse multiposition Thomson scattering diagnostic, under construction at RTP, is discussed. Light from a double pulsed ruby laser (pulse separation: 10{endash}800 {mu}s, max. 2{times}12.5 J) is scattered by the free electrons of the tokamak plasma and relayed to a Littrow polychromator for spectral analysis. The spectrally resolved light is recorded by two ICCD detectors. Simulations show that the system sensitivity will be such that electron temperatures in the range of 100 eV{endash}7 keV can be determined with an accuracy as good as 2{percent}{endash}3{percent} for electron densities of 10{sup 20} m{sup {minus}3}, with a spatial resolution down to 2.6 mm. With this diagnostic the dynamics of small scale structures in the electron temperature profile will be studied. {copyright} {ital 1997 American Institute of Physics.}
Pumping angular momentum by driven chaotic scattering
T. Dittrich; F. L. Dubeibe
2008-04-29
Chaotic scattering with an internal degree of freedom and the possibility to generate directed transport of angular momentum is studied in a specific model, a magnetic dipole moving in a periodically modulated magnetic field confined to a compact region in space. We show that this system is an irregular scatterer in large parts of its parameter space. If in addition all spatio-temporal symmetries are broken, directed transport of mass as well as angular momentum occurs. The sensitive parameter dependence of the corresponding currents includes frequent sign reversals. Zeros of either quantity entail the exclusive occurrence of the other and thus give rise in particular to angular-momentum separation without mass transport as a classical analogue of spin-polarized currents.
Ab initio alpha-alpha scattering
Serdar Elhatisari; Dean Lee; Gautam Rupak; Evgeny Epelbaum; Hermann Krebs; Timo A. Lähde; Thomas Luu; Ulf-G. Meißner
2015-06-11
Processes involving alpha particles and alpha-like nuclei comprise a major part of stellar nucleosynthesis and hypothesized mechanisms for thermonuclear supernovae. In an effort towards understanding alpha processes from first principles, we describe in this letter the first ab initio calculation of alpha-alpha scattering. We use lattice effective field theory to describe the low-energy interactions of nucleons and apply a technique called the adiabatic projection method to reduce the eight-body system to an effective two-cluster system. We find good agreement between lattice results and experimental phase shifts for S-wave and D-wave scattering. The computational scaling with particle number suggests that alpha processes involving heavier nuclei are also within reach in the near future.
Ab initio alpha-alpha scattering
Elhatisari, Serdar; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A; Luu, Thomas; Meißner, Ulf-G
2015-01-01
Processes involving alpha particles and alpha-like nuclei comprise a major part of stellar nucleosynthesis and hypothesized mechanisms for thermonuclear supernovae. In an effort towards understanding alpha processes from first principles, we describe in this letter the first ab initio calculation of alpha-alpha scattering. We use lattice effective field theory to describe the low-energy interactions of nucleons and apply a technique called the adiabatic projection method to reduce the eight-body system to an effective two-cluster system. We find good agreement between lattice results and experimental phase shifts for S-wave and D-wave scattering. The computational scaling with particle number suggests that alpha processes involving heavier nuclei are also within reach in the near future.
Multiple Scattering Measurements in the MICE Experiment
Carlisle, T.; Cobb, J.; Neuffer, D.; /Fermilab
2012-05-01
The international Muon Ionization Cooling Experiment (MICE), under construction at RAL, will test a prototype cooling channel for a future Neutrino Factory or Muon Collider. The cooling channel aims to achieve, using liquid hydrogen absorbers, a 10% reduction in transverse emittance. The change in 4D emittance will be determined with an accuracy of 1% by measuring muons individually. Step IV of MICE will make the first precise emittance-reduction measurements of the experiment. Simulation studies using G4MICE, based on GEANT4, find a significant difference in multiple scattering in low Z materials, compared with the standard expression quoted by the Particle Data Group. Direct measurement of multiple scattering using the scintillating-fibre trackers is found to be possible, but requires the measurement resolution to be unfolded from the data.
Optical theorem and elastic nucleon scattering
Milos V. Lokajicek; Vojtech Kundrat
2009-06-22
In the theoretical analysis of high-energy elastic nucleon scattering one starts commonly from the description based on the validity of optical theorem, which allows to derive the value of total cross section directly from the experimentally measured t-dependence of elastic differential cross section. It may be shown, however, that this theorem has been derived on the basis of one assumption that might be regarded perhaps as acceptable for long-range (e.g., Coulomb) forces but must be denoted as quite unacceptable for finite-range hadron forces. Consequently, the conclusions leading to the increase of total cross section with energy at higher collision energies must be newly analyzed. The necessity of new analysis concerns also the derivation of elastic scattering t-dependence at very low transverse momenta from measured data.
Correlation-length bounds, and estimates for intermittent islands in parabolic SPDEs
Conus, Daniel; Khoshnevisan, Davar
2011-01-01
We consider the nonlinear stochastic heat equation in one dimension. Under some conditions on the nonlinearity, we show that the "peaks" of the solution are rare, almost fractal like. We also provide an upper bound on the length of the "islands," the regions of large values. These results are obtained by analyzing the correlation length of the solution.
Estimating the correlation length of inhomogeneities in a polycrystalline Igor Simonovski*
Cizelj, Leon
such as the random orientation, shape and size of the grains. A crystal plasticity material model was applied rules. Keywords: Correlation length; Polycrystalline material; Crystal plasticity; 2 #12;1 INTRODUCTION size. The correlation length can therefore be considered as an indicator of first plastic deformations
VALVE: Variable Length Value Encoder for Off-Chip Data Buses. Dinesh C. Suresh, Banit Agrawal*
Najjar, Walid A.
VALVE: Variable Length Value Encoder for Off-Chip Data Buses. Dinesh C. Suresh, Banit Agrawal (VALVE) technique to reduce the power consumption in the off-chip data buses. While past research has proposed scheme is capable of detecting and encoding variable length bit patterns in the data values. VALVE
Estimating Total Length of Headless White Hake, Urophycis tenuis, Landed in Maine
Estimating Total Length of Headless White Hake, Urophycis tenuis, Landed in Maine EDWIN P. CREASER, little is known about the length composition of this species landed from Maine fishing vessels sampling personnel of the Maine Department of Marine Resources to develop an easy and rapid method
Length: 4-15 mm Larvae (maggots): Creamy-white to green or
Isaacs, Rufus
Hover fly Syrphidae Length: 4-15 mm Larvae (maggots): Creamy-white to green or brown. Worm flies" or "flower flies"). Eggs: Small (1 mm in length). Cylindrical, white and laid singly on leaves or shoots near aphid colonies. 15 mm4 mm #12;Pupae: Green, tan or brown. Typically pear- shaped with a pair
TESLA-FEL 2004-01 Silica Aerogel Radiators for Bunch Length
TESLA-FEL 2004-01 Silica Aerogel Radiators for Bunch Length Measurements J. BÂ¨ahr a , V. Djordjadze aerogel are used to measure the electron bunch length at the photo injector test facility at DESY Zeuthen by the usage of aerogel is calculated analytically and Monte Carlo simulations are performed. It is shown
Variable length pattern coding for power reduction in off-chip data buses
Venkitasubramanian Iyer, Jayakrishnan
2009-05-15
indicating the index of the match is sent. If a variable length pattern match occurs then the code and unmatched portion of data is sent. We implemented our scheme, Variable Length Pattern Coding (VLPC) for various integer and floating point benchmarks...
Surface Free Energies, Interfacial Tensions and Correlation Lengths of the ABF Models
Pearce, Paul A.
Surface Free Energies, Interfacial Tensions and Correlation Lengths of the ABF Models David L. O. Abstract The surface free energies, interfacial tensions and correlation lengths of the Andrews been established there are various quan- tities of physical interest, such as the surface free energies
Gardel, Margaret
Thick Filament Length and Isoform Composition Determine Self-Organized Contractile Units motors are clustered into thick filaments. Although the role of mechanochemistry is well appreciated, the extent to which thick filament length regulates actomyosin contractility is unknown. Here, we study
Classification of Self-Dual Codes of Length 36 Masaaki Harada
Harada, Masaaki
by eight. Two codes are equivalent if one can be obtained from the other by permuting the coordinates. An automorphism of C is a permutation of the coordinates of C which preserves C. The set consisting of all-dual codes of lengths up to 30 and doubly even self-dual codes of length 32 is known (see [9, Table I
Scanning microscopy using a short-focal-length Fresnel zone plate
Scanning microscopy using a short-focal-length Fresnel zone plate Ethan Schonbrun,* Winnie N. Ye demonstrate a form of scanning microscopy using a short-focal-length Fresnel zone plate and a low-NA relay. In this scheme, parallel scanning microscopy using a Fresnel zone-plate array would require only a single spatial
A Simple Biomass-Based Length-Cohort Analysis for Estimating Biomass and Fishing Mortality
A Simple Biomass-Based Length-Cohort Analysis for Estimating Biomass and Fishing Mortality CHANG IK, Washington 98115, USA Abstract.--A biomass-based length-cohort analysis (LCA) was examined for its performance in estimating total stock biomass and fishing mortality (F) for a population in equilibrium. We
Inclusive Deep-Inelastic Scattering at HERA
Zhiqing Zhang; for the H1; ZEUS Collaborations
2014-12-19
This contribution covers three recent results on deep-inelastic scattering at HERA: (i) new measurements of the proton longitudinal structure function $F_L$ from H1 and ZEUS experiments, (ii) a dedicated NC cross section measurement from ZEUS in the region of high Bjorken $x$, and (iii) preliminary combination results of all HERA inclusive data published up to now by H1 and ZEUS, taking into account the experimental correlations between measurements.
Plasmonic nanoparticle scattering for color holograms
Montelongo, Yunuen; Tenorio-Pearl, Jaime Oscar; Williams, Calum; Zhang, Shuang; Milne, William Ireland; Wilkinson, Timothy David
2014-09-02
resolution limit in optical microscopy or the storage capacity for optical memory devices. Holography in the subwavelength domain has been somewhat limited to the treatment of nanostructures with effective medium theory (EMT), for either dielectrics (10, 11... limitations of all of the optical devices in- volved (4–6). Here we use narrow-band scattering points to pro- duce two simultaneous independent color holograms in plane. Interestingly, in contrast with the traditional concept of optical information storage, we...
Virtual Compton Scattering: Results from Jefferson Lab
L. Van Hoorebeke
2003-05-01
Virtual Compton Scattering o013 the proton has been studied at Q 2 -values of 1:0 and 1:9 (GeV=c) 2 in Hall A at the Thomas Je013erson National Accelerator Facility (JLab). Data were taken below and above the pion production threshold as well as in the resonance region. Results obtained below pion threshold at Q 2 = 1:0 (GeV=c) 2 are presented in this paper.
Tetraquark Production in Double Parton Scattering
F. Carvalho; E. R. Cazaroto; V. P. Gonçalves; F. S. Navarra
2015-11-23
We develop a model to study tetraquark production in hadronic collisions. We focus on double parton scattering and formulate a version of the color evaporation model for the production of the $X(3872)$ and of the $T_{4c}$ tetraquark, a state composed by the $c \\bar{c} c \\bar{c}$ quarks. We find that the production cross section grows rapidly with the collision energy $\\sqrt{s}$ and make predictions for the forthcoming higher energy data of the LHC.
Thomson scattering for core plasma on DEMO
Mukhin, E. E.; Kurskiev, G. S.; Tolstyakov, S. Yu.; Bukreev, I. M.; Chernakov, P. V.; Kochergin, M. M.; Koval, A. N.; Litvinov, A. E.; Masyukevich, S. V.; Razdobarin, A. G.; Semenov, V. V. [Ioffe Physical Technical Institute, 26 Polytechnicheskaya St., St. Petersburg (Russian Federation); Kukushkin, A. B.; Sdvizhenskii, P. A. [NRC Kurchatov Institute, 1, Akademika Kurchatova pl., Moscow, 123182 (Russian Federation); Andrew, P. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France)
2014-08-21
This paper describes the challenges of Thomson scattering implementation for core plasma on DEMO and evaluates the capability to measure extremely high electron temperature range 0.5-40keV. A number of solutions to be developed for ITER diagnostics are suggested in consideration of their realization for DEMO. New approaches suggested for DEMO may also be of interest to ITER and currently operating magnetic confinement devices.
Timelike Compton scattering off the neutron
Marie Boër; Michel Guidal; Marc Vanderhaeghen
2015-10-10
We study the exclusive photoproduction of an electron-positron pair on a neutron target in the Jefferson Lab energy domain. The reaction consists of two processes: the Bethe-Heitler and the Timelike Compton Scattering. The latter process provides potentially access to the Generalized Parton Distributions (GPDs) of the nucleon. We calculate all the unpolarized, single- and double-spin observables of the reaction and study their sensitivities to GPDs.
Scattering off the Color Glass Condensate
Heikki Mäntysaari
2015-06-24
In this thesis the Color Glass Condensate (CGC) framework, which describes quantum chromodynamics (QCD) at high energy, is applied to various scattering processes. Higher order corrections to the CGC evolution equations, known as the BK and JIMWLK equations, are also considered. It is shown that the leading order CGC calculations describe the experimental data from electron-proton deep inelastic scattering (DIS), proton-proton and proton-nucleus collisions. The initial condition for the BK evolution equation is obtained by performing a fit to deep inelastic scattering data. The fit result is used as an input to calculations of single particle spectra and nuclear suppression in proton-proton and proton-nucleus collisions, which are shown to be in agreement with RHIC and LHC measurements. In particular, the importance of a proper description of the nuclear geometry consistently with the DIS data fits is emphasized, as it results in a nuclear suppression factor $R_{pA}$ which is consistent with the available experimental data. In addition to single particle production, the correlations between two hadrons at forward rapidity are computed. The RHIC measurements are shown to be naturally explainable in the CGC framework, and the previous CGC calculations are improved by including the so called inelastic and double parton scattering contributions. This improvement is shown to be required in order to get results compatible with the experimentally measured correlations. Exclusive vector meson production, which can be a powerful tool to study the gluonic structure of nuclei at small Bjorken-$x$, is also considered. The cross sections are calculated within the CGC framework in the context of a future electron-ion collider. In particular, the cross section for incoherent diffractive vector meson production is derived and a centrality estimator for this process is proposed.
Ice thickness measurements by Raman scattering
Pershin, Sergey M; Klinkov, Vladimir K; Yulmetov, Renat N; Bunkin, Alexey F
2014-01-01
A compact Raman LIDAR system with a spectrograph was used for express ice thickness measurements. The difference between the Raman spectra of ice and liquid water is employed to locate the ice-water interface while elastic scattering was used for air-ice surface detection. This approach yields an error of only 2 mm for an 80-mm-thick ice sample, indicating that it is promising express noncontact thickness measurements technique in field experiments.
Yano, M., E-mail: masao-yano-aa@mail.toyota.co.jp; Manabe, A.; Shoji, T.; Kato, A. [Advanced Material Engineering Division, Toyota Motor Corporation, Susono 410-1193 (Japan); Ono, K. [High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801 (Japan); Harada, M. [Toyota Central R and D Labs, Inc., Aichi 480-1192 (Japan); Kohlbrecher, J. [Laboratory for Neutron Scattering, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)
2014-05-07
The magnetic reversal behaviors of single domain sized Nd-Fe-B permanent magnets, with and without isolation between the Nd{sub 2}Fe{sub 14}B grains, was clarified using small-angle neutron scattering (SANS). The SANS patterns obtained arose from changes in the magnetic domains and were analyzed using the Teubner–Stray model, a phenomenological correlation length model, to quantify the periodicity and morphology of the magnetic domains. The results indicated that the magnetic reversal evolved with the magnetic domains that had similar sized grains. The grain isolation enabled us to realize the reversals of single domains.
De Flaviis, Franco
Tilt Beam Characteristic by Changing Length of Finite-Sized Square Dielectric Substrate of One Arm by changing the length of finite-sized square dielectric substrate of one arm rectangular spiral antenna has). Horizontal spiral arm length (HL) is varied from HL=0.8o to HL=5.2o to choose the length that yields
Spin Dependence of Dark Matter Scattering
Vernon Barger; Wai-Yee Keung; Gabe Shaughnessy
2008-06-11
New experiments designed to discover a weakly interacting dark matter (DM) particle via spin dependent scattering can distinguish models of electroweak symmetry breaking. The plane of spin dependent versus spin independent DM scattering cross sections is a powerful model diagnostic. We detail representative predictions of mSUGRA, singlet extended SM and MSSM, a new Dirac neutrino, Littlest Higgs with T-parity (LHT) and Minimal Universal Extra Dimensions (mUED) models. Of these models, the nMSSM has the largest spin dependent (SD) cross section. It has a very light neutralino which would give lower energy nuclear recoils. The Focus Point region of mSUGRA, mUED and the right handed neutrino also predict a very large SD cross section and predict a large signal of high energy neutrinos in the IceCube experiment from annihilations of dark matter in the Sun. We also describe a model independent treatment of the scattering of DM particles of different intrinsic spins.
Scattering off the Color Glass Condensate
Mäntysaari, Heikki
2015-01-01
In this thesis the Color Glass Condensate (CGC) framework, which describes quantum chromodynamics (QCD) at high energy, is applied to various scattering processes. Higher order corrections to the CGC evolution equations, known as the BK and JIMWLK equations, are also considered. It is shown that the leading order CGC calculations describe the experimental data from electron-proton deep inelastic scattering (DIS), proton-proton and proton-nucleus collisions. The initial condition for the BK evolution equation is obtained by performing a fit to deep inelastic scattering data. The fit result is used as an input to calculations of single particle spectra and nuclear suppression in proton-proton and proton-nucleus collisions, which are shown to be in agreement with RHIC and LHC measurements. In particular, the importance of a proper description of the nuclear geometry consistently with the DIS data fits is emphasized, as it results in a nuclear suppression factor $R_{pA}$ which is consistent with the available exp...
Scattering properties of dark atoms and molecules
Cline, James M; Moore, Guy; Xue, Wei
2013-01-01
There has been renewed interest in the possibility that dark matter exists in the form of atoms, analogous to those of the visible world. An important input for understanding the cosmological consequences of dark atoms is their self-scattering. Making use of results from atomic physics for the potentials between hydrogen atoms, we compute the low-energy elastic scattering cross sections for dark atoms. We find an intricate dependence upon the ratio of the dark proton to electron mass, allowing for the possibility to "design" low-energy features in the cross section. Dependences upon other parameters, namely the gauge coupling and reduced mass, scale out of the problem by using atomic units. We derive constraints on the parameter space of dark atoms by demanding that their scattering cross section does not exceed bounds from dark matter halo shapes. We discuss the formation of molecular dark hydrogen in the universe, and determine the analogous constraints on the model when the dark matter is predominantly in ...
Double parton scattering at high energies
Antoni Szczurek
2015-04-24
We discuss a few examples of rich newly developing field of double parton scattering. We start our presentation from production of two pairs of charm quark-antiquark and argue that it is the golden reaction to study the double parton scattering effects. In addition to the DPS we consider briefly also mechanism of single parton scattering and show that it gives much smaller contribution to the $c \\bar c c \\bar c$ final state. Next we discuss a perturbative parton-splitting mechanism which should be included in addition to the conventional DPS mechanism. We show that the presence of this mechanism unavoidably leads to collision energy and other kinematical variables dependence of so-called $\\sigma_{eff}$ parameter being extracted from different experiments. Next we briefly discuss production of four jets. We concentrate on estimation of the contribution of DPS for jets remote in rapidity. Understanding of this contribution is very important in the context of searches for BFKL effects known under the the name Mueller-Navelet jets. We discuss the situation in a more general context. Finally we briefly mention about DPS effects in production of $W^+ W^-$. Outlook closes the presentation.
Scattering amplitudes in super-renormalizable gravity
Pietro Donŕ; Stefano Giaccari; Leonardo Modesto; Leslaw Rachwal; Yiwei Zhu
2015-06-15
We explicitly compute the tree-level on-shell four-graviton amplitudes in four, five and six dimensions for local and weakly nonlocal gravitational theories that are quadratic in both, the Ricci and scalar curvature with form factors of the d'Alembertian operator inserted between. More specifically we are interested in renormalizable, super-renormalizable or finite theories. The scattering amplitudes for these theories turn out to be the same as the ones of Einstein gravity regardless of the explicit form of the form factors. As a special case the four-graviton scattering amplitudes in Weyl conformal gravity are identically zero. Using a field redefinition, we prove that the outcome is correct for any number of external gravitons (on-shell $n-$point functions) and in any dimension for a large class of theories. However, when an operator quadratic in the Riemann tensor is added in any dimension (with the exception of the Gauss-Bonnet term in four dimensions) the result is completely altered, and the scattering amplitudes depend on all the form factors introduced in the action.
Scattering amplitudes in super-renormalizable gravity
Donŕ, Pietro; Modesto, Leonardo; Rachwal, Leslaw; Zhu, Yiwei
2015-01-01
We explicitly compute the tree-level on-shell four-graviton amplitudes in four, five and six dimensions for local and weakly nonlocal gravitational theories that are quadratic in both, the Ricci and scalar curvature with form factors of the d'Alembertian operator inserted between. More specifically we are interested in renormalizable, super-renormalizable or finite theories. The scattering amplitudes for these theories turn out to be the same as the ones of Einstein gravity regardless of the explicit form of the form factors. As a special case the four-graviton scattering amplitudes in Weyl conformal gravity are identically zero. Using a field redefinition, we prove that the outcome is correct for any number of external gravitons (on-shell $n-$point functions) and in any dimension for a large class of theories. However, when an operator quadratic in the Riemann tensor is added in any dimension (with the exception of the Gauss-Bonnet term in four dimensions) the result is completely altered, and the scattering...
Scattering Theory for Open Quantum Systems
J. Behrndt; M. M. Malamud; H. Neidhardt
2006-10-31
Quantum systems which interact with their environment are often modeled by maximal dissipative operators or so-called Pseudo-Hamiltonians. In this paper the scattering theory for such open systems is considered. First it is assumed that a single maximal dissipative operator $A_D$ in a Hilbert space $\\sH$ is used to describe an open quantum system. In this case the minimal self-adjoint dilation $\\widetilde K$ of $A_D$ can be regarded as the Hamiltonian of a closed system which contains the open system $\\{A_D,\\sH\\}$, but since $\\widetilde K$ is necessarily not semibounded from below, this model is difficult to interpret from a physical point of view. In the second part of the paper an open quantum system is modeled with a family $\\{A(\\mu)\\}$ of maximal dissipative operators depending on energy $\\mu$, and it is shown that the open system can be embedded into a closed system where the Hamiltonian is semibounded. Surprisingly it turns out that the corresponding scattering matrix can be completely recovered from scattering matrices of single Pseudo-Hamiltonians as in the first part of the paper. The general results are applied to a class of Sturm-Liouville operators arising in dissipative and quantum transmitting Schr\\"{o}dinger-Poisson systems.
Seismic scattering in the subduction zone of the Middle America region
Dominguez, Luis Antonio
2012-01-01
vi 4 Scattering of seismic waves in heterogenousvii 6 Evaluation of seismic scattering usingan alternative seismic network . .
Stewart, G.; Lackner, M.; Haid, L.; Matha, D.; Jonkman, J.; Robertson, A.
2013-07-01
With the push towards siting wind turbines farther offshore due to higher wind quality and less visibility, floating offshore wind turbines, which can be located in deep water, are becoming an economically attractive option. The International Electrotechnical Commission's (IEC) 61400-3 design standard covers fixed-bottom offshore wind turbines, but there are a number of new research questions that need to be answered to modify these standards so that they are applicable to floating wind turbines. One issue is the appropriate simulation length needed for floating turbines. This paper will discuss the results from a study assessing the impact of simulation length on the ultimate and fatigue loads of the structure, and will address uncertainties associated with changing the simulation length for the analyzed floating platform. Recommendations of required simulation length based on load uncertainty will be made and compared to current simulation length requirements.
Relativistic models for quasielastic electron and neutrino-nucleus scattering
Carlotta Giusti; Andrea Meucci
2012-12-12
Relativistic models developed within the framework of the impulse approximation for quasielastic (QE) electron scattering and successfully tested in comparison with electron-scattering data have been extended to neutrino-nucleus scattering. Different descriptions of final-state interactions (FSI) in the inclusive scattering are compared. In the relativistic Green's function (RGF) model FSI are described consistently with the exclusive scattering using a complex optical potential. In the relativistic mean field (RMF) model FSI are described by the same RMF potential which gives the bound states. The results of the models are compared for electron and neutrino scattering and, for neutrino scattering, with the recently measured charged-current QE (CCQE) MiniBooNE cross sections.
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.
Boothroyd, Andrew
Concepts of Neutron ScatteringConcepts of Neutron Scattering 66thth PSI Summer School on Condensed Andrew Boothroyd University of Oxford Basic features of neutron scattering Neutron diffraction Neutron on the lattice * * * #12;ScatteringScattering ``nuts and boltsnuts and bolts'' Neutrons, photons, electrons
Stimulated Raman scattering of laser dye mixtures dissolved in multiple scattering media
Yashchuk, V P; Komyshan, A O; Tikhonov, E A; Olkhovyk, L A
2014-10-31
Stimulated Raman scattering (SRS) of a mixture of rhodamine 6G and pyrromethene 605 laser dyes in vesicular films is studied. It is shown that a peculiar interaction of dyes occurs under conditions of multiple scattering of light from vesicles. This interaction manifests itself as SRS excitation of one of the dyes by random lasing of the other dye, provided that the random lasing spectrum overlaps the Stokes lines of the first dye. In addition, there is energy transfer between molecules of these dyes if their luminescence and absorption spectra overlap. The results obtained confirm that the mechanism of SRS from laser dyes in multiple scattering media is similar to that in coherent-active Raman spectroscopy. These results extend the possibility of determining the vibrational spectrum of dye molecules from their secondary radiation in these media. (nonlinear optical phenomena)
SU-C-12A-06: A Universal Definition for CT Irradiated Length
McKenney, S; Bakalyar, D [Henry Ford Health System, Detroit, MI (United States); Boone, J [UC Davis Medical Center, Sacramento, CA (United States)
2014-06-01
Purpose: The length of scan shown or calculated from the console is the distance between the center of the starting and ending images. The irradiated length for such a set of images can vary substantially from this distance, depending on the acquisition mode. We propose that the rise to equilibrium function h(?) be used to uniquely define an irradiated length independent of the details of the scanning process. This method also seamlessly accommodates recent developments in active collimation. Method: h(?) is determined along the central axis of a long cylindrical phantom, ideally from integration of the dose spread function. For practical reasons h(?) may be approximated from helical scans with real-time dose rate measurements or from a series of central dose measurements using finite irradiated length exposures. For a particular scan then, the irradiated length ? is calculated from a central dose measurement of h and then applying the inverse function h(?){sup -1}. Results: h(?) was determined from measurements made in a prototype ICRU/TG200 phantom, 60 cm long and 30 cm in diameter. The resultant ? generally agreed with indicated scan length plus one beam width for axial and indicated scan length for helical scans if overscanning was accounted for. For most scanners, DLP/CTDIvol is a good measure of irradiated length allowing for another index of comparison. Conclusion: Central dose measurements with a small chamber along with the rise to equilibrium function h(?) provide us with a robust and consistent means of determining scan length independent of the means of irradiation over a variety of scanners and scanning conditions. The method is limited to ? significantly less than the equilibrium.
The Harmonic Oscillator in the Classical Limit of a Minimal-Length Scenario
Quintela, T S; Nogueira, J A
2015-01-01
In this work we explicitly solve the problem of the harmonic oscillator in the classical limit of a minimal-length scenario. We show that (i) the motion equation of the oscillator is not linear anymore because the presence of a minimal length introduces an anarmonic term and (ii) its motion is described by a Jacobi sine elliptic function. Therefore the motion is still periodic with the new period depending on the minimal length. This result is very important since it can be used to probe the Planck-scale physics. We show applications of our results in spectroscopy and gravity.
A Bunch Length Monitor for JLab 12 GeV Upgrade
Ahmad, Mahmoud Mohamad Ali; Freyberger, Arne P.; Gubeli, Joseph F.; Krafft, Geoffrey A.
2013-12-01
A continuous non-invasive bunch length monitor for the 12 GeV upgrade of Jefferson Lab will be used to determine the bunch length of the beam. The measurement will be done at the fourth dipole of the injector chicane at 123 MeV using the coherent synchrotron light emitted from the dipole. The estimated bunch length is 333 fs. A vacuum chamber will be fabricated and a Radiabeam real time interferometer will be used. In this paper, background, the estimated calculations and the construction of the chamber will be discussed.
The effect of stride length alterations on running efficiency in beginning runners
James, Jerry Lynn
1980-01-01
summary table for caloric cost 2 Descriptive statistics for caloric cost 3 Duncan's New Nultiple Range Test for Stride Length 18 20 LIST OF FIGURES F1gure Page l The eff1cient range of a runner 2 The relat1ve roles of Stride Rate and Stride... Length in velocity changes 3 A two-by-three (sex-by-stride length) repeated measures design 4 A bar chart of the caloric cost means of SL-A, SL-B, and SL-C w1thout distinction between sexes l7 22 5 A bar chart of the caloric cost means of each...
Basics of Ion Scattering in Nanoscale Materials
Whitlow, Harry J.; Zhang, Yanwen
2010-01-01
Energetic ions interact with materials by collisions with the nuclei and electrons of the atoms that make up the material. In these collisions energy and momentum is transferred from the projectile particle which is a moving atom or ion, to the target particles (atomic nucleus or electron). Each collision leads to a slowing down of the moving projectile and also a deflection of the trajectory which gives rise to the term scattering which is often used synonymously to describe the energy transfer process. In this chapter, we introduce from an experimental viewpoint the underlying theory for interaction of ions for analysis and modification of nanometer scale materials. A more detailed theoretical overview of the topic can be found in the recent monographs by Sigmund. Detailed derivations of the formulae introduced will not be given here but can be found in standard texts that are indicated by references. The treatment here starts by considering an individual scattering event. The results are then used to consider the effects on the primary ion in the limit where a large number of collisions take place. Subsequently, the primary effects are considered in nanometer materials which approach the thin-medium limit where the primary particles encounter only limited number of scattering centers. Finally, the dissipation of the energy deposited by the primary projectiles in secondary processes such as cascades of displaced atoms and electrons will be considered in the thick and thin medium limits. This approach was chosen because it builds upon the standard concepts in ion-matter interactions that are well know and have been widely used in experimental measurements of the stopping force and applications such as Rutherford backscattering spectrometry (RBS), ion beam modification of materials etc.
A NEW ANALYSIS OF INTRABEAM SCATTERING
Nash, B
2004-09-15
Beginning with the Fokker-Planck equation we present a new analysis of intrabeam scattering (IBS) in electron storage rings. Our approach is distinguished by having no ill-defined Coulomb logarithm, a fundamental drawback of previous approaches. We treat the case of linear x{sub {beta}}Y{sub {beta}} coupling in detail, deriving explicit expressions for the second moment invariants and their time evolution in the presence of IBS. We compare our results with those of Bjorken-Mtingwa, as well as with measurements performed at KEK's ATF damping ring. More details of our derivations will be published elsewhere.
Resonant and non-resonant magnetic scattering
McWhan, D.B.; Hastings, J.B.; Kao, C.C.; Siddons, D.P.
1991-12-31
The tunability and the polarization of synchrotron radiation open upon new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and thy fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation.
Resonant and non-resonant magnetic scattering
McWhan, D.B.; Hastings, J.B.; Kao, C.C.; Siddons, D.P.
1991-01-01
The tunability and the polarization of synchrotron radiation open upon new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and thy fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation.
Giant resonance study by 6li scattering
Chen, Xinfeng
2009-05-15
used to study giant resonances (see Ref. [20])...... 7 FIG. 2.1 Coordinates relation for folding calculation. ..................................................... 32 FIG. 2.2 A sample input file of DFPD4. The number 1 - 8 on the left side represent... of the crosssection for inelastic scattering from 116 Sn for 1.6 MeV wide bin centered at E x =12.62, 22.20, 30.17 MeV of the giant resonance peak and the continuum along with DWBA fits.. ............................ 99 FIG.4.14 E0, E1, E2 and E3 Strength...
A modified variational approach to scattering
Parnell, Gregory Elliott
1978-01-01
that where Wg mr P (rj= ZrZ e (2. 9) in the units Eq. (2. 2). The Schrddinger wave equation for the system, H% = EW, then becomes ? '7- ? ?, +, -, ]I ? E'i t 22 s Ig, Iq &g! where E is the total energy of the system. This may be written [fl+H+ tj~p~](1... scattering, ft, is the bound electron wavefunction, and/& is the free electron wavefunction. Then, and (2. 7) where the P i&, (r) are the reduced radial eigenfunctions of the isolated nC hydrogenlike atom problem, gr) is analogously the reduced radial...
Electromagnetic wave scattering by many small particles
A. G. Ramm
2006-08-18
Scattering of electromagnetic waves by many small particles of arbitrary shapes is reduced rigorously to solving linear algebraic system of equations bypassing the usual usage of integral equations. The matrix elements of this linear algebraic system have physical meaning. They are expressed in terms of the electric and magnetic polarizability tensors. Analytical formulas are given for calculation of these tensors with any desired accuracy for homogeneous bodies of arbitrary shapes. An idea to create a "smart" material by embedding many small particles in a given region is formulated.
Transient Rayleigh scattering from single semiconductor nanowires
Montazeri, Mohammad; Jackson, Howard E.; Smith, Leigh M.; Yarrison-Rice, Jan M.; Kang, Jung-Hyun; Gao, Qiang; Tan, Hark Hoe; Jagadish, Chennupati
2013-12-04
Transient Rayleigh scattering spectroscopy is a new pump-probe technique to study the dynamics and cooling of photo-excited carriers in single semiconductor nanowires. By studying the evolution of the transient Rayleigh spectrum in time after excitation, one can measure the time evolution of the density and temperature of photo-excited electron-hole plasma (EHP) as they equilibrate with lattice. This provides detailed information of dynamics and cooling of carriers including linear and bimolecular recombination properties, carrier transport characteristics, and the energy-loss rate of hot electron-hole plasma through the emission of LO and acoustic phonons.
Dispersion corrections to parity violating electron scattering
Gorchtein, M.; Horowitz, C. J. [Nuclear Theory Center, Indiana University, Bloomington, IN 47408 (United States); Ramsey-Musolf, M. J. [University of Wisconsin-Madison, Madison, WI 53706 (United States)
2010-08-04
We consider the dispersion correction to elastic parity violating electron-proton scattering due to {gamma}Z exchange. In a recent publication, this correction was reported to be substantially larger than the previous estimates. In this paper, we study the dispersion correction in greater detail. We confirm the size of the disperion correction to be {approx}6% for the QWEAK experiment designed to measure the proton weak charge. We enumerate parameters that have to be constrained to better than relative 30% in order to keep the theoretical uncertainty for QWEAK under control.
Total Cross Sections for Neutron Scattering
C. R. Chinn; Ch. Elster; R. M. Thaler; S. P. Weppner
1994-10-19
Measurements of neutron total cross-sections are both extensive and extremely accurate. Although they place a strong constraint on theoretically constructed models, there are relatively few comparisons of predictions with experiment. The total cross-sections for neutron scattering from $^{16}$O and $^{40}$Ca are calculated as a function of energy from $50-700$~MeV laboratory energy with a microscopic first order optical potential derived within the framework of the Watson expansion. Although these results are already in qualitative agreement with the data, the inclusion of medium corrections to the propagator is essential to correctly predict the energy dependence given by the experiment.
Cold neutron scattering in imperfect deuterium crystals
Andrzej Adamczak
2010-12-10
The differential cross sections for cold neutron scattering in mosaic deuterium crystals have been calculated for various target temperatures. The theoretical results are compared with the recent experimental data for the neutron wavelengths $\\lambda\\approx$~1--9~\\AA. It is shown that the structures of observed Bragg peaks can be explained by the mosaic spread of about $3^{\\circ}$ and contributions from a~limited number of crystal orientations. Such a~crystal structure should be also taken into account in ultracold neutron upscattering due to the coherent phonon annihilation in solid deuterium.
Deeply Virtual Compton Scattering off the neutron
M. Mazouz; A. Camsonne; C. Muńoz Camacho; for the Jefferson Lab Hall A collaboration
2007-12-12
The present experiment exploits the interference between the Deeply Virtual Compton Scattering (DVCS) and the Bethe-Heitler processes to extract the imaginary part of DVCS amplitudes on the neutron and on the deuteron from the helicity-dependent D$({\\vec e},e'\\gamma)X$ cross section measured at $Q^2$=1.9 GeV$^2$ and $x_B$=0.36. We extract a linear combination of generalized parton distributions (GPDs) particularly sensitive to $E_q$, the least constrained GPD. A model dependent constraint on the contribution of the up and down quarks to the nucleon spin is deduced.
Neutron scattering and extra short range interactions
V. V. Nesvizhevsky; G. Pignol; K. V. Protasov
2007-11-14
The available data on neutron scattering were analyzed to constrain a hypothetical new short-range interaction. We show that these constraints are several orders of magnitude better than those usually cited in the range between 1 pm and 5 nm. This distance range occupies an intermediate space between collider searches for strongly coupled heavy bosons and searches for new weak macroscopic forces. We emphasise the reliability of the neutron constraints in so far as they provide several independent strategies. We have identified the most promising way to improve them.
MFTF Thomson scattering: a system study
Frank, A.M.
1980-09-11
This report documents the design effort for a Thomson scattering diagnostic system for MFTF. The principal problem is obtaining enough photons, in the presence of a poorly known background, to make satisfactory measurements. No currently available laser will yield enough photons to do this. Design concepts for imaging and detection are discussed. The ability of components to survive in the high-radiation environment of MFTF is identified as an important problem. The transition to MFTF-B makes many of the problems identified here more serious.
Scattering of singular beams by subwavelength objects
Hemo, Evyatar; Shamir, Joseph
2013-01-01
In recent years, there has been a mounting interest in better methods of measuring nanoscale objects, especially in fields such as nanotechnology, biomedicine, cleantech, and microelectronics. Conventional methods have proved insufficient, due to the classical diffraction limit or slow and complicated measuring procedures. The purpose of this paper is to explore the special characteristics of singular beams with respect to the investigation of subwavelength objects. Singular beams are light beams that contain one or more singularities in their physical parameters, such as phase or polarization. We focus on the three-dimensional interaction between electromagnetic waves and subwavelength objects to extract information about the object from the scattered light patterns.
Quadratic electroweak corrections for polarized Moller scattering
A. Aleksejevs, S. Barkanova, Y. Kolomensky, E. Kuraev, V. Zykunov
2012-01-01
The paper discusses the two-loop (NNLO) electroweak radiative corrections to the parity violating electron-electron scattering asymmetry induced by squaring one-loop diagrams. The calculations are relevant for the ultra-precise 11 GeV MOLLER experiment planned at Jefferson Laboratory and experiments at high-energy future electron colliders. The imaginary parts of the amplitudes are taken into consideration consistently in both the infrared-finite and divergent terms. The size of the obtained partial correction is significant, which indicates a need for a complete study of the two-loop electroweak radiative corrections in order to meet the precision goals of future experiments.
Fano resonances in scattering: an alternative perspective
Lukas Schwarz; Holger Cartarius; Günter Wunner; Walter Dieter Heiss; Jörg Main
2015-06-24
In a previous paper it has been shown that the interference of the first and second order pole of the Green's function at an exceptional point, as well as the interference of the first order poles in the vicinity of the exceptional point, gives rise to asymmetric scattering cross section profiles. In the present paper we demonstrate that these line profiles are indeed well described by the Beutler-Fano formula, and thus are genuine Fano resonances. Also further away from the exceptional points excellent agreement can be found by introducing energy dependent Fano parameters.
SMB, Small Angle X-Ray Scattering
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Popov, M V; Bartel, N; Gwinn, C R; Johnson, M D; Joshi, B C; Kardashev, N S; Karuppusamy, R; Kovalev, Y Y; Kramer, M; Rudnitskii, A G; Safutdinov, E R; Shishov, V I; Smirnova, T V; Soglasnov, V A; Zensus, J A; Zhuravlev, V I
2015-01-01
We studied scattering properties of the pulsar PSR B0329+54 with a ground-space radio interferometer RadioAstron which included the 10-m Space Radio Telescope, the 110-m Green Bank Telescope, the 14x25-m Westerbork Synthesis Radio Telescope, and the 64-m Kalyazin Radio Telescope. The observations were performed at 324 MHz on baselines of up to 235,000 km in November 2012 and January 2014. At short ground-space baselines of less than about 20,000 km, the visibility amplitude decreases with the projected baseline length, providing a direct measurement of the diameter of the scattering disk of 4.7$\\pm$0.9 mas. The size of the diffraction spot near Earth is 15,000$\\pm$3,000 km. At longer baselines of up to 235,000 km, where no interferometric detection of the scattering disk would be expected, significant visibilities were observed with amplitudes scattered around a constant value. These detections result in a discovery of a substructure in the completely resolved scatter-broadened image of the pointlike source, ...
Effects of graded distribution of scattering centers on ballistic transport
Mitran, T. L.; Nemnes, G. A.; Ion, L.; Dragoman, Daniela
2014-09-28
The transmission coefficient of a two dimensional scattering region connected to ideal leads was calculated for the case of electrons interacting with an inhomogeneous distribution of repulsive or attractive scattering centers. The scattering centers with Gaussian profiles were positioned at regular intervals perpendicular to the transport direction, but were spaced according to a power law along this direction. The transmission function was obtained using a scattering formalism based on the R-matrix method. The simulations revealed that although, overall, the transmission coefficient decreases and becomes almost monotonously dependent on energy as the inhomogeneity of both attractive and repulsive scattering centers increases, the redistribution of transmission between open channels depends on the type of scattering centers.
Chen, Wei-Ren [ORNL; Do, Changwoo [ORNL; Egami, T [University of Tennessee, Knoxville (UTK); Hong, Kunlun [ORNL; Li, Xin [ORNL; Liu, Emily [Rensselaer Polytechnic Institute (RPI); Liu, Yun [National Institute of Standards and Technology (NIST); Porcar, L. [National Institute of Standards and Technology (NIST); Smith, Gregory Scott [ORNL; Smith, Sean C [ORNL; Wu, Bin [ORNL
2012-01-01
Atomistic molecular dynamics (MD) simulations and contrast variation small angle neutron scattering (SANS) technique have been used to investigate the generation-5 (G5) polyelectrolyte polyamidoamine (PAMAM) starburst dendrimer with respect to its conformational dependence on counterion behavior at different levels of molecular charge. Satisfactory agreement is seen between the simulated results, such as the excess intra-dendrimer scattering length density (SLD) distribution and hydration level, and their experimental counterparts. The conformational evolution of charged dendrimer appears to be highly dependent on the association behavior of counterion. We explore the nature of the distribution of counterions around charged amines and qualitatively account for its sensitivity to the counterion valency on the difference of excess free energy. Moreover, via extending the concept of electrical double layer for compact charged colloids, we define an effective radius of charged dendrimer based on the spatial distribution of counterions in its vicinity. Within the same framework, the correlation between the strength of intra-dendrimer electrostatic repulsion and counterion valency and dynamics is also addressed.
A high resolution multiposition Thomson scattering system for the Rijnhuizen Tokamak Project
Barth, C.J.; Beurskens, M.N.; Chu, C.C.; Donne, A.J.; Lopes Cardozo, N.J.; Herranz, J.; v.d. Meiden, H.J.; Pijper, F.J. [FOM-Instituut voor Plasmafysica `Rijnhuizen`, Association EURATOM-FOM, P.O. Box 1207, 3430 BE Nieuwegein (The Netherlands)] [FOM-Instituut voor Plasmafysica `Rijnhuizen`, Association EURATOM-FOM, P.O. Box 1207, 3430 BE Nieuwegein (The Netherlands)
1997-09-01
A high resolution multiposition Thomson scattering setup to measure the electron temperature (T{sub e}) and density (n{sub e}) of a hot plasma is described. The system is operational at the Rijnhuizen Tokamak Project. Light from a high power pulsed ruby laser is scattered by the free plasma electrons and relayed to a Littrow polychromator for spectral analysis. The spectrally and spatially resolved light is detected by a GaAsP photocathode. The two-dimensional image is intensified and recorded with a charge-coupled device camera. T{sub e} in the range of 50 eV{endash}6 keV can be measured at 115 spatial elements of 2.6 mm length along the laser beam. The observation error is {lt}6{percent} at n{sub e}=2{times}10{sup 19} m{sup {minus}3} and smaller for higher n{sub e}. The high resolution and accuracy enabled the observation of small scale structures in T{sub e} and n{sub e}. {copyright} {ital 1997 American Institute of Physics.}
An evaluation of inductance loop detector lead length and optimal speed trap distance
Hamm, Robert Alan
1994-01-01
component of freeway management systems is the inductance loop detector. This research effort evaluated the use of inductance loop detectors in a freeway management situation to determine maximum permissible lead lengths and an optimal speed trap distance...
2013-01-01
stained in the cells as brightly as the full PTN, but with aFull length PTN or any mutant that contains the black domain and either grey domain (represented by black lines) can transform cells
The dynamics of genomic-length DNA molecules in 100-nm channels
Wang, Yan Mei
Prinz*, Han Cao , Steven Chou , Walter W. Reisner , Robert Riehn , Yan Mei Wang , Edward C. Cox§ , James w, and contour length L, such that (pw)1/5 L3/5 . Compare this form with the result expected
McGehee, Michael
of their prom- ise as low-cost solutions for the world's energy needs.13 Efficiencies under simulated solar thicknesses, a model can be fitted to the data and an exciton diffusion length extracted. Important consid
Length regulation of microtubules by molecular motors: Exact solution and density profiles
Arita, Chikashi; Santen, Ludger
2015-01-01
In this work we study a microtubule (MT) model , whose length is regulated by the action of processive kinesin motors. We treat the case of infinite processivity, i.e. particle exchange in the bulk is neglected. The exact results can be obtained for model parameters which correspond to a finite length of the MT. In contrast to the model with particle exchange we find that the lengths of the MT are exponentially distributed in this parameter regime. The remaining parameter space of the model, which corresponds to diverging MT lengths, is analyzed by means of extensive Monte-Carlo simulations and a macroscopic approach. For divergent MTs we find a complex structure of the phase diagram in terms of shapes of the density profile.
Telomere Length in Circulating Leukocytes Is Associated with Lung Function and Disease
Nyholt, Dale R.
Telomere Length in Circulating Leukocytes Is Associated with Lung Function and Disease Eva Albrecht. Comprehensive Pneumology Center Munich (CPC-M), Member of the German Center for Lung Research, Munich, Germany
Zabaras, Nicholas J.
Multi-length scale design of deformation processes for control of orientation (texture) dependent properties Shankar Ganapathysubramanian and Nicholas Zabaras Materials Process Design and Control Laboratory are quite sensitive to the anisotropy of these crystalline materials. Process optimization is especially
Qurz 2 SOLUTIONS, SECTION ALL (10 pts.) Find the length of the ...
Jony
Qurz 2 SOLUTIONS, SECTION ALL. (10 pts.) Find the length of the curve. Solution. Using the formula for the arclength, of a curve onthe interval [0, 2],. 0. (5 pts.) ...
Impact of carbon nanotube length on electron transport in aligned carbon nanotube networks
Lee, Jeonyoon
Here, we quantify the electron transport properties of aligned carbon nanotube (CNT) networks as a function of the CNT length, where the electrical conductivities may be tuned by up to 10× with anisotropies exceeding 40%. ...
expansion. Given bone's inherent mechanosensitivity, low intensity vibration (LIV), a mechanical signal-frequency mechanical signals induced via low intensity vibration (LIV) are anabolic to bone, perhaps servingOriginal Full Length Article Low magnitude mechanical signals mitigate osteopenia without
Bunch length measurement at the Fermilab A0 photoinjector using a Martin-Puplett interferometer
Thurman-Keup, Randy; Fliller, Raymond Patrick; Kazakevich, Grigory; /Fermilab
2008-05-01
We present preliminary measurements of the electron bunch lengths at the Fermilab A0 Photoinjector using a Martin-Puplett interferometer on loan from DESY. The photoinjector provides a relatively wide range of bunch lengths through laser pulse width adjustment and compression of the beam using a magnetic chicane. We present comparisons of data with simulations that account for diffraction distortions in the signal and discuss future plans for improving the measurement.
Viscosity of plant oils as a function of temperature, fatty acid chain length, and unsaturation
Neo, Tong Heng
1988-01-01
VISCOS1TY OF PLANT OILS AS A FUNCTION OF TEMPERATURE, FATIY ACID CHAIN LENGTH, AND UNSATURATION A Thesis by TONG HENG NEO Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 1988 Major Subject: Agricultural Engineering VISCOSITY OF PLANT OILS AS A FUNCTION OF TEMPERATURE, FATTY ACID CHAIN LENGTH, AND UNSATURATION A Thesis by TONG HENG NEO Approved as to style and content by...
Effect of tube length on laboratory displacement of oil by CO?
Turki, Wafik Hussein
1973-01-01
EFFECT OF TUBE LENGTH ON LABORATORY DISPLACEMENT OF OIL BY CO 2 A Thesis by WAFIK H. " TURKI Submitted to the Graduate College of Texas AhM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE December... 1973 Major Subject: Petroleum Engineering EFFECT OF TUBE LENGTH ON LABORATORY DISPLACEMENT OF OIL BY CO A Thesis by WAFIK H. TURKI Approved as to style and content by: (Chair n of Committee) (Head of Department) (Member) (Member ) Z. ~-g...
Direct Scattering Processes and Signatures of Chaos in Quantum Waveguides
G. B. Akguc; L. E. Reichl
2003-02-14
The effect of direct processes on the statistical properties of deterministic scattering processes in a chaotic waveguide is examined. The single channel Poisson kernel describes well the distribution of S-matrix eigenphases when evaluated over an energy interval. When direct processes are transformed away, the scattering processes exhibit universal random matrix behavior. The effect of chaos on scattering wavefunctions,eigenphases, and time delays is discussed.
Quantum Monte Carlo calculations of neutron-alpha scattering
Kenneth M. Nollett; Steven C. Pieper; R. B. Wiringa; J. Carlson; G. M. Hale
2006-12-09
We describe a new method to treat low-energy scattering problems in few-nucleon systems, and we apply it to the five-body case of neutron-alpha scattering. The method allows precise calculations of low-lying resonances and their widths. We find that a good three-nucleon interaction is crucial to obtain an accurate description of neutron-alpha scattering.
Variational Calculations of Positronium Scattering with Hydrogen
Woods, Denton
2015-01-01
Positronium-hydrogen (Ps-H) scattering is of interest, as it is a fundamental four-body Coulomb problem. We have investigated low-energy Ps-H scattering below the Ps(n=2) excitation threshold using the Kohn variational method and variants of the method with a trial wavefunction that includes highly correlated Hylleraas-type short-range terms. We give an elegant formalism that combines all Kohn-type variational methods into a single form. Along with this, we have also developed a general formalism for Kohn-type matrix elements that allows us to evaluate arbitrary partial waves with a single codebase. Computational strategies we have developed and use in this work are also discussed. With these methods, we have computed phase shifts for the first six partial waves for both the singlet and triplet states. The $^{1,3}$S and $^{1,3}$P phase shifts are highly accurate results and could potentially be viewed as benchmark results. Resonance positions and widths for the $^1$S-, $^1$P-, $^1$D-, and $^1$F-waves have bee...
Scattering theory approach to electrodynamic Casimir forces
Rahi, Sahand Jamal; Kardar, Mehran [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, Santa Barbara, California 93106 (United States); Emig, Thorsten [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, Santa Barbara, California 93106 (United States); Institut fuer Theoretische Physik, Universitaet zu Koeln, Zuelpicher Strasse 77, 50937 Koeln (Germany); Laboratoire de Physique Theorique et Modeles Statistiques, CNRS UMR 8626, Universite Paris-Sud, 91405 Orsay cedex (France); Graham, Noah [Department of Physics, Middlebury College, Middlebury, Vermont 05753 (United States); Jaffe, Robert L. [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Center for Theoretical Physics, Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
2009-10-15
We give a comprehensive presentation of methods for calculating the Casimir force to arbitrary accuracy, for any number of objects, arbitrary shapes, susceptibility functions, and separations. The technique is applicable to objects immersed in media other than vacuum, nonzero temperatures, and spatial arrangements in which one object is enclosed in another. Our method combines each object's classical electromagnetic scattering amplitude with universal translation matrices, which convert between the bases used to calculate scattering for each object, but are otherwise independent of the details of the individual objects. The method is illustrated by rederiving the Lifshitz formula for infinite half-spaces, by demonstrating the Casimir-Polder to van der Waals crossover, and by computing the Casimir interaction energy of two infinite, parallel, perfect metal cylinders either inside or outside one another. Furthermore, it is used to obtain new results, namely, the Casimir energies of a sphere or a cylinder opposite a plate, all with finite permittivity and permeability, to leading order at large separation.
Stimulated Brillouin scattering in solid aerosols
Chitanvis, S.M.
1988-08-01
We estimate the differential scattering cross-section due to SBS in a glass bead which is much larger than the wavelength of a high energy laser beam which irradiates it. We consider three possible scenarios: neither the incident nor the Stokes wavelength is on a Mie resonance; only the Stokes wavelength is on resonance; and the incident wavelength and the Stokes wavelength are on a Mie resonance. For the first two cases, we find that the SBS scattering cross-section is extremely small compared to the geometric/Mie cross-section. It follows as a corollary that SBS in a glass bead will be insufficient to shatter it in these two cases. In the last case, it is quite possible that due to the buildup of high fields on-resonance within the spherical bead, the bead might be shattered. The chance of such an event occurring in a polydisperse distribution of spherical beads is generally not expected to be very high. 3 figs.
Age-related changes in the plasticity and toughness of human cortical bone at multiple length-scales
Zimmermann, Elizabeth A.; Schaible, Eric; Bale, Hrishikesh; Barth, Holly D.; Tang, Simon Y.; Reichert, Peter; Busse, Bjoern; Alliston, Tamara; Ager III, Joel W.; Ritchie, Robert O.
2011-08-10
The structure of human cortical bone evolves over multiple length-scales from its basic constituents of collagen and hydroxyapatite at the nanoscale to osteonal structures at nearmillimeter dimensions, which all provide the basis for its mechanical properties. To resist fracture, bone’s toughness is derived intrinsically through plasticity (e.g., fibrillar sliding) at structural-scales typically below a micron and extrinsically (i.e., during crack growth) through mechanisms (e.g., crack deflection/bridging) generated at larger structural-scales. Biological factors such as aging lead to a markedly increased fracture risk, which is often associated with an age-related loss in bone mass (bone quantity). However, we find that age-related structural changes can significantly degrade the fracture resistance (bone quality) over multiple lengthscales. Using in situ small-/wide-angle x-ray scattering/diffraction to characterize sub-micron structural changes and synchrotron x-ray computed tomography and in situ fracture-toughness measurements in the scanning electron microscope to characterize effects at micron-scales, we show how these age-related structural changes at differing size-scales degrade both the intrinsic and extrinsic toughness of bone. Specifically, we attribute the loss in toughness to increased non-enzymatic collagen cross-linking which suppresses plasticity at nanoscale dimensions and to an increased osteonal density which limits the potency of crack-bridging mechanisms at micron-scales. The link between these processes is that the increased stiffness of the cross-linked collagen requires energy to be absorbed by “plastic” deformation at higher structural levels, which occurs by the process of microcracking.
Chen, Zheng [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China)
2011-02-15
Large discrepancies among the laminar flame speeds and Markstein lengths of methane/air mixtures measured by different researchers using the same constant-pressure spherical flame method are observed. As an effort to reduce these discrepancies, one linear model (LM, the stretched flame speed changes linearly with the stretch rate) and two non-linear models (NM I and NM II, the stretched flame speed changes non-linearly with the stretch rate) for extracting the laminar flame speed and Markstein length from propagating spherical flames are investigated. The accuracy and performance of the LM, NM I, and NM II are found to strongly depend on the Lewis number. It is demonstrated that NM I is the most accurate for mixtures with large Lewis number (positive Markstein length) while NM II is the most accurate for mixtures with small Lewis number (negative Markstein length). Therefore, in order to get accurate laminar flame speed and Markstein length from spherical flame experiments, different non-linear models should be used for different mixtures. The validity of the theoretical results is further demonstrated by numerical and experimental studies. The results of this study can be used directly in spherical flame experiments measuring the laminar flame speed and Markstein length. (author)
Nayaz Khalid Ahmed; Martin Hecht
2009-11-09
In microfluidics, varying wetting properties, expressed in terms of the local slip length, can be used to influence the flow of a liquid through a device. We study flow past surfaces on which the slip length is modulated in stripes. We find that the effective slip length for such a flow can be expressed as a function of the individual slip lengths on the stripes. The angle dependence of the effective slip is in excellent agreement with a recent theory describing the slip length as a tensorial quantity. This tensorial nature allows to induce a transverse flow, which can be used in micro mixers to drive a vortex. In our simulations of a flow through a square channel with patterned surfaces we see a homogeneous rotation about the direction of the flow. We investigate the influence of patterns of cosine shaped varying local slip on the flow field depending on the orientation of the pattern and find the largest effective slip length for periods of stripes parallel to the flow direction.
A Model for Fiber Length Attrition in Injection-Molded Long-Fiber Composites
TuckerIII, Charles L. [University of Illinois, Urbana-Champaign; Phelps, Jay H [University of Illinois, Urbana-Champaign; El-Rahman, Ahmed Abd [University of Illinois, Urbana-Champaign; Kunc, Vlastimil [ORNL
2013-01-01
Long-fiber thermoplastic (LFT) composites consist of an engineering thermoplastic matrix with glass or carbon reinforcing fibers that are initially 10 to 13 mm long. When an LFT is injection molded, flow during mold filling orients the fibers and degrades the fiber length. Fiber orientation models for injection molding are well developed, and special orientation models for LFTs have been developed. Here we present a detailed quantitative model for fiber length attrition in a flowing fiber suspension. The model tracks a discrete fiber length distribution (FLD) at each spatial node. Key equations are a conservation equation for total fiber length, and a breakage rate equation. The breakage rate is based on buckling of fibers due to hydrodynamic forces, when the fibers are in unfavorable orientations. The FLD model is combined with a mold filling simulation to predict spatial and temporal variations in fiber length distribution in a mold cavity during filling. The predictions compare well to experiments on a glassfiber/ PP LFT molding. Fiber length distributions predicted by the model are easily incorporated into micromechanics models to predict the stress-strain behavior of molded LFT materials. Author to whom correspondence should be addressed; electronic mail: ctucker@illinois.edu 1
Observation of the Second Harmonic in Thomson Scattering from...
Office of Scientific and Technical Information (OSTI)
Observation of the Second Harmonic in Thomson Scattering from Relativistic Electrons Citation Details In-Document Search Title: Observation of the Second Harmonic in Thomson...
Proton-Proton Scattering at 340 MeV
Chamberlain, Owen; Wiegand, Clyde
2008-01-01
on Nuclear Physics. Basil. High yner gy Neutron- protonand Proton~proton Scattering 9 Helv. Phys. Acta (in press J a review
Test of factorization in diffractive deep inelastic scattering...
Office of Scientific and Technical Information (OSTI)
Test of factorization in diffractive deep inelastic scattering and photoproduction at HERA Citation Details In-Document Search Title: Test of factorization in diffractive deep...
Electromagnetic wave scattering by many conducting small particles
A. G. Ramm
2008-04-21
A rigorous theory of electromagnetic (EM) wave scattering by small perfectly conducting particles is developed. The limiting case when the number of particles tends to infinity is discussed.
Probing Spatial, Electronic Structures with X-ray Scattering...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Probing Spatial, Electronic Structures with X-ray Scattering, Spectroscopic Techniques Wednesday, September 5, 2012 - 10:45am SLAC, Bldg. 137, Room 226 Gang Chen Seminar:...
Coupled-channel scattering in 1 + 1 dimensional lattice model
Guo, Peng [JLAB
2013-07-01
Based on the Lippmann-Schwinger equation approach, a generalized Lüscher’s formula in 1+1 dimensions for two particles scattering in both the elastic and coupled-channel cases in moving frames is derived. A two-dimensional coupled-channel scattering lattice model is presented, which represents a two-coupled-channel resonant scattering scalars system. The Monte Carlo simulation is performed on finite lattices and in various moving frames. The two-dimensional generalized Lüscher’s formula is used to extract the scattering amplitudes for the coupled-channel system from the discrete finite-volume spectrum.
Signal evaluations using singular value decomposition for Thomson scattering diagnostics
Tojo, H., E-mail: tojo.hiroshi@jaea.go.jp; Yatsuka, E.; Hatae, T.; Itami, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka 311-0193 (Japan); Yamada, I.; Yasuhara, R.; Funaba, H.; Hayashi, H. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)
2014-11-15
This paper provides a novel method for evaluating signal intensities in incoherent Thomson scattering diagnostics. A double-pass Thomson scattering system, where a laser passes through the plasma twice, generates two scattering pulses from the plasma. Evaluations of the signal intensities in the spectrometer are sometimes difficult due to noise and stray light. We apply the singular value decomposition method to Thomson scattering data with strong noise components. Results show that the average accuracy of the measured electron temperature (T{sub e}) is superior to that of temperature obtained using a low-pass filter (<20 MHz) or without any filters.
Numerical solution of inverse scattering for near-field optics
2007-04-30
May 2, 2007 ... tering problem that arises in near-field optics, which reconstructs the scatterer of an inhomogeneous me- dium located on a substrate from data ...
The Algebraic Approach to the Phase Problem for Neutron Scattering
A. Cervellino; S. Ciccariello
2004-01-27
The algebraic approach to the phase problem for the case of X-ray scattering from an ideal crystal is extended to the case of the neutron scattering, overcoming the difficulty related to the non-positivity of the scattering density. In this way, it is proven that the atomicity is the crucial assumption while the positiveness of the scattering density only affects the method for searching the basic sets of reflections. We also report the algebraic expression of the determinants of the Karle-Hauptman matrices generated by the basic sets with the most elongated shape along one of the reciprocal crystallographic axes.
ORNL study uses neutron scattering, supercomputing to demystify...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Morgan McCorkle Communications and Media Relations 865.574.7308 ORNL study uses neutron scattering, supercomputing to demystify forces at play in biofuel production This graphical...
Inverse medium scattering for the Helmholtz equation at fixed ...
2005-09-03
Feb 23, 2012 ... More importantly, we give an explicit energy estimate for the scattered field, ...... We used the commonly used compressed row storage.
Numerical solution of an inverse medium scattering problem for ...
"Gang Bao; Peijun Li"
2009-04-24
Apr 1, 2009 ... An energy estimate for the scattered field is obtained on ...... We use the compressed row storage format, which makes no assumptions about.
Sharp upper bounds on the number of the scattering poles
We study the scattering poles of a compactly supported “black box” perturbations of the Laplacian in Rn, n odd. We prove a sharp upper bound of the counting ...
Chin, Y.H.
2011-01-01
for a quick estimate of the FEL parameters which minimizefor the Optimization of the FEL Gain Length Including thet h e Optimization o f the FEL Gain Length Including t h e
Liu, J; Bourland, J [Wake Forest University, Winston-salem, NC (United States)
2014-06-01
Purpose: To analytically estimate first-order x-ray scatter for kV cone beam x-ray imaging with high computational efficiency. Methods: In calculating first-order scatter using the Klein-Nishina formula, we found that by integrating the point-to-point scatter along an interaction line, a “pencil-beam” scatter kernel (BSK) can be approximated to a quartic expression when the imaging field is small. This BSK model for monoenergetic, 100keV x-rays has been verified on homogeneous cube and cylinder water phantoms by comparing with the exact implementation of KN formula. For heterogeneous medium, the water-equivalent length of a BSK was acquired with an improved Siddon's ray-tracing algorithm, which was also used in calculating pre- and post- scattering attenuation. To include the electron binding effect for scattering of low-kV photons, the mean corresponding scattering angle is determined from the effective point of scattered photons of a BSK. The behavior of polyenergetic x-rays was also investigated for 120kV x-rays incident to a sandwiched infinite heterogeneous slab phantom, with the electron binding effect incorporated. Exact computation and Monte Carlo simulations were performed for comparisons, using the EGSnrc code package. Results: By reducing the 3D volumetric target (o(n{sup 3})) to 2D pencil-beams (o(n{sup 2})), the computation expense can be generally lowered by n times, which our experience verifies. The scatter distribution on a flat detector shows high agreement between the analytic BSK model and exact calculations. The pixel-to-pixel differences are within (-2%, 2%) for the homogeneous cube and cylinder phantoms and within (0, 6%) for the heterogeneous slab phantom. However, the Monte Carlo simulation shows increased deviation of the BSK model toward detector periphery. Conclusion: The proposed BSK model, accommodating polyenergetic x-rays and electron binding effect at low kV, shows great potential in efficiently estimating the first-order scatter from small imaging fields. We are investigating more thoroughly to improve performance and explore applications.
New structures in scattering amplitudes: a review
Paolo Benincasa
2013-12-19
We review some recent developments in the understanding of field theories in the perturbative regime. In particular, we discuss the notions of analyticity, unitarity and locality, and therefore the singularity structure of scattering amplitudes in general interacting theories. We describe their tree-level structure and their on-shell representations, as well as the links between the tree-level structure itself and the structure of the loop amplitudes. Finally, we describe the on-shell diagrammatics recently proposed both on general grounds and in the remarkable example of planar supersymmetric theories. This review is partially based on lectures given at: Dipartimento di Fisica and INFN, Universit\\`a di Bologna; Departamento de F{\\i}sica de Part{\\i}culas, Universidade de Santiago de Compostela; and as part of the program Strings@ar Lectures on Advanced Topics of High Energy Physics held at the IAFE
Quantum Chaotic Scattering in Microwave Resonators
B. Dietz; T. Friedrich; H. L. Harney; M. Miski-Oglu; A. Richter; F. Schaefer; H. A. Weidenmueller
2010-02-24
In a frequency range where a microwave resonator simulates a chaotic quantum billiard, we have measured moduli and phases of reflection and transmission amplitudes in the regimes of both isolated and of weakly overlapping resonances and for resonators with and without time-reversal invariance. Statistical measures for S-matrix fluctuations were determined from the data and compared with extant and/or newly derived theoretical results obtained from the random-matrix approach to quantum chaotic scattering. The latter contained a small number of fit parameters. The large data sets taken made it possible to test the theoretical expressions with unprecedented accuracy. The theory is confirmed by both, a goodness-of-fit-test and the agreement of predicted values for those statistical measures that were not used for the fits, with the data.
The scattering and extinction properties of nanodiamonds
Rai, Rakesh K
2009-01-01
The study of scattering and extinction properties of possible nanodiamond grains in the ISM are reported. Calculations using Discrete Dipole Approximation (DDA) for varying ellipsoidal shapes and sizes from 2.5 to $10 nm$ are considered. Nanodiamonds show negligible extinction from IR to near-UV and very sharp far-UV rise. Comparison with observations rule out possibility of independent nanodiamond dust but point towards possibility of nanodiamonds as a component in the ISM. Radiation induced transformations may lead to carbonaceous grains with different core and mantles. So calculations are also performed for a core-mantle target model with nanodiamond core in graphite mantles. The graphite extinction features get modified with the peak at 2175 \\AA{} being lowered, broadened, blue shifted and accompanied by enhanced extinction in the far-UV. Such variations in the 2175 \\AA{} band and simultaneous far-UV rise are observed along some sources. A three component dust model incorporating silicate, graphite and gr...
Technical Report: Rayleigh Scattering Combustion Diagnostic
Adams, Wyatt; Hecht, Ethan
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.
Green's Function Approach to Inclusive Electron Scattering
F. Capuzzi; C. Giusti; A. Meucci; F. D. Pacati
2003-11-21
A Green's function approach to the inclusive quasielastic ($e,e'$) scattering is presented. The components of the nuclear response are written in terms of the single-particle optical model Green's function. The explicit calculation of the Green's function can be avoided by its spectral representation, which is based on a biorthogonal expansion in terms of the eigenfunctions of the non-Hermitian optical potential and of its Hermitian conjugate. This allows one to treat final state interactions consistently in the inclusive ($e,e'$) and in the exclusive ($e,e'N$) reactions. Numerical results for the longitudinal and transverse response functions obtained in a nonrelativistic and in a relativistic framework are presented and discussed also in comparison with data.
Unitary constraints on Deeply Virtual Compton Scattering
J.M. Laget
2007-11-01
At moderately low momentum transfer ($-t$ up to 1 GeV$^2$) the coupling to the vector meson production channels gives the dominant contribution to real Compton and deeply virtual Compton scattering (DVCS). Starting from a Regge Pole approach that successfully describes vector meson production, the singular part of the corresponding box diagrams (where the intermediate vector meson-baryon pair propagates on-shell) is evaluated without any further assumptions (unitarity). Such a treatment explains not only the unexpectedly large DVCS unpolarized cross section that has been recently measured at Jefferson Laboratory (JLab), but also all the beam spin and charge asymmetries that has been measured at JLab and Hermes, without explicit need of Generalized Parton Distributions (GPD). The issue of the relationship between the two approaches is addressed.
Scattering om two Aharonov-Bohm vortices
Eugene Bogomolny
2015-08-19
The problem of two Aharonov-Bohm (AB) vortices for the Helmholtz equation is examined in detail. It is demonstrated that the method proposed in [J. M. Myers, J. Math. Phys. \\textbf{6}, 1839 (1963)] for diffraction on a slit can be generalized to get an explicit solution for AB vortices. Due to singular nature of AB interaction the Green function and the scattering amplitude for two AB vortices obey a series of partial differential equations. Coefficients entering these equations, in their turn, fulfill ordinary non-linear differential equations whose solutions can be obtained from a solution of the Painleve V (or III) equation. The asymptotics of necessary functions for very large and very small distances between two vortices are calculated explicitly. Taken together, it means that the problem of two AB vortices is integrable.
Improved Wireless Performance from Mode Scattering in Ventilation Ducts
Stancil, Daniel D.
Improved Wireless Performance from Mode Scattering in Ventilation Ducts Benjamin E. Henty, PA 15230. henty@eirp.org and stancil@cmu.edu Abstract Ventilation ducts are a convenient undesirable in a ven- tilation duct setting. With this in mind we investigate the mode scattering effects
nova.tex, 781996. SCATTERING OF LIGHT BY FREE ELECTRONS
Rodriguez, Carlos
nova.tex, 7Â8Â1996. SCATTERING OF LIGHT BY FREE ELECTRONS as a Test of Quantum Theory \\Lambda E. T. RELATIVISTIC BASIS OF THE SCHR Â¨ ODINGER EQUATION 9 8. NON--ARISTOTELIAN SCATTERING OF LIGHT BY ELECTRONS 10 9 dominates every home and office. But on the other hand, this very fact makes it seem strange that a meeting
Discrete Fourier transform in nanostructures using scattering Michael N. Leuenbergera)
Flatte, Michael E.
Discrete Fourier transform in nanostructures using scattering Michael N. Leuenbergera) and Michael that the discrete Fourier transform DFT can be performed by scattering a coherent particle or laser beam off the initial vector into the two-dimensional potential by means of electric gates, the Fourier
Heterodyne coherent anti-Stokes Raman scattering (CARS) imaging
Potma, Eric Olaf
Heterodyne coherent anti-Stokes Raman scattering (CARS) imaging Eric O. Potma,* Conor L. Evans with heterodyne co- herent anti-Stokes Raman scattering (CARS) interferometric microscopy. This technique that is linear in the concentration of vibrational modes. We show that heterodyne CARS microscopy permits
Studying Deeply Virtual Compton Scattering with Neural Networks
Kresimir Kumericki; Dieter Mueller; Andreas Schafer
2011-10-17
Neural networks are utilized to fit Compton form factor H to HERMES data on deeply virtual Compton scattering off unpolarized protons. We used this result to predict the beam charge-spin assymetry for muon scattering off proton at the kinematics of the COMPASS II experiment.
Using Back-Scattering to Enhance Efficiency in Neutron Detectors
Kittelmann, Thomas; Cai, Xiao Xiao; Kanaki, Kalliopi; Cooper-Jensen, Carsten P; Hall-Wilton, Richard
2015-01-01
The principle of using strongly scattering materials to recover efficiency in neutron detectors, via back-scattering of unconverted thermal neutrons, is discussed in general. Feasibility of the method is illustrated through Geant4-based simulations of a specific setup involving a moderator-like material placed behind a single layered boron-10 thin film gaseous detector.
Nonlinear Thomson scattering: A tutoriala... Y. Y. Lau,b)
Umstadter, Donald
scattering. An important current application of these scattering processes is the generation of ultrashort an intense laser and of an energetic electron beam in x-ray production. The close analogy with free electron. INTRODUCTION The widespread availability and the continuous develop- ment of ultra-high intensity lasers have
A light scattering study of colloid-polymer mixtures
Pirie, Angus D
A detailed light scattering study of non-equilibrium states found in a model colloid-polymer mixture is presented. Conventional light scattering is used to examine the average structure of the phase, over a wide range of wavevectors. For all non...
Charged impurity-induced scatterings in chemical vapor deposited graphene
Li, Ming-Yang; Tang, Chiu-Chun [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Ling, D. C. [Department of Physics, Tamkang University, Tamsui Dist., New Taipei 25137, Taiwan (China); Li, L. J. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 11529, Taiwan (China); Chi, C. C.; Chen, Jeng-Chung [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan (China)
2013-12-21
We investigate the effects of defect scatterings on the electric transport properties of chemical vapor deposited (CVD) graphene by measuring the carrier density dependence of the magneto-conductivity. To clarify the dominant scattering mechanism, we perform extensive measurements on large-area samples with different mobility to exclude the edge effect. We analyze our data with the major scattering mechanisms such as short-range static scatters, short-range screened Coulomb disorders, and weak-localization (WL). We establish that the charged impurities are the predominant scatters because there is a strong correlation between the mobility and the charge impurity density. Near the charge neutral point (CNP), the electron-hole puddles that are induced by the charged impurities enhance the inter-valley scattering, which is favorable for WL observations. Away from the CNP, the charged-impurity-induced scattering is weak because of the effective screening by the charge carriers. As a result, the local static structural defects govern the charge transport. Our findings provide compelling evidence for understanding the scattering mechanisms in graphene and pave the way for the improvement of fabrication techniques to achieve high-quality CVD graphene.
Efimov physics in bosonic atom-trimer scattering
Deltuva, A. [Centro de Fisica Nuclear da Universidade de Lisboa, P-1649-003 Lisboa (Portugal)
2010-10-15
Bosonic atom-trimer scattering is studied in the unitary limit using momentum-space equations for four-particle transition operators. The impact of the Efimov effect on the atom-trimer scattering observables is explored, and a number of universal relations is established. Positions and widths of tetramer resonances are determined. The trimer relaxation rate constant is calculated.
Emergence of a measurement basis in atom-photon scattering
Yinnon Glickman; Shlomi Kotler; Nitzan Akerman; Roee Ozeri
2012-06-18
The process of quantum measurement has been a long standing source of debate. A measurement is postulated to collapse a wavefunction onto one of the states of a predetermined set - the measurement basis. This basis origin is not specified within quantum mechanics. According to the theory of decohernce, a measurement basis is singled out by the nature of coupling of a quantum system to its environment. Here we show how a measurement basis emerges in the evolution of the electronic spin of a single trapped atomic ion due to spontaneous photon scattering. Using quantum process tomography we visualize the projection of all spin directions, onto this basis, as a photon is scattered. These basis spin states are found to be aligned with the scattered photon propagation direction. In accordance with decohernce theory, they are subjected to a minimal increase in entropy due to the photon scattering, while, orthogonal states become fully mixed and their entropy is maximally increased. Moreover, we show that detection of the scattered photon polarization measures the spin state of the ion, in the emerging basis, with high fidelity. Lastly, we show that while photon scattering entangles all superpositions of pointer states with the scattered photon polarization, the measurement-basis states themselves remain classically correlated with it. Our findings show that photon scattering by atomic spin superpositions fulfils all the requirements from a quantum measurement process.
Radiative heat transfer in inhomogeneous, nongray, and anisotropically scattering media
Guo, Zhixiong "James"
Radiative heat transfer in inhomogeneous, nongray, and anisotropically scattering media Zhixiong Radiative heat transfer in three-dimensional inhomogeneous, nongray and anisotropically scattering of an application of engineering interest, radiative heat transfer in a boiler model with non-isothermal, nongray
Scattering E#ects in the TESLA Colllimation Adriana Bungau
Scattering E#ects in the TESLA Colllimation System Adriana Bungau University of Manchester scattering angles and random output direction. In the TESLA TDR simulations, the collimation depth was set of the particles which strike the TESLA collima tors can not be possible without taking into consideration
SCATTERING POLES FOR NEGATIVE POTENTIALS Andr'as Vasy
Vasy, AndrĂˇs
SCATTERING POLES FOR NEGATIVE POTENTIALS Andr'as Vasy Mathematics Department, MIT Cambridge, MA number of poles in P and they correspond to the bound states of the Hamiltonian \\Delta +V (\\Delta is the positive Laplacian). In [5] Zworski has shown that the number of scattering poles n(r) in a disc of radius
Simulation-Length Requirements in the Loads Analysis of Offshore Floating Wind Turbines: Preprint
Haid, L.; Stewart, G.; Jonkman, J.; Robertson, A.; Lackner, M.; Matha, D.
2013-06-01
The goal of this paper is to examine the appropriate length of a floating offshore wind turbine (FOWT) simulation - a fundamental question that needs to be answered to develop design requirements. To examine this issue, a loads analysis of an example FOWT was performed in FAST with varying simulation lengths. The offshore wind system used was the OC3-Hywind spar buoy, which was developed for use in the International Energy Agency Code Comparison Collaborative Project and supports NREL's offshore 5-megawatt baseline turbine. Realistic metocean data from the National Oceanic and Atmospheric Administration and repeated periodic wind files were used to excite the structure. The results of the analysis clearly show that loads do not increase for longer simulations. In regards to fatigue, a sensitivity analysis shows that the procedure used for counting half cycles is more important than the simulation length itself. Based on these results, neither the simulation length nor the periodic wind files affect response statistics and loads for FOWTs (at least for the spar studied here); a result in contrast to the offshore oil and gas industry, where running simulations of at least 3 hours in length is common practice.
Seng, Y. S.; Lee, P.; Rawat, R. S.
2014-11-15
The breakdown phase of the UNU-ICTP plasma focus (PF) device was successfully simulated using the electromagnetic particle in cell method. A clear uplift of the current sheath (CS) layer was observed near the insulator surface, accompanied with an exponential increase in the plasma density. Both phenomena were found to coincide with the surge in the electric current, which is indicative of voltage breakdown. Simulations performed on the device with different insulator lengths showed an increase in the fast ionization wave velocity with length. The voltage breakdown time was found to scale linearly with the insulator length. Different spatial profiles of the CS electron density, and the associated degree of uniformity, were found to vary with different insulator lengths. The ordering, according to the degree of uniformity, among insulator lengths of 19, 22, and 26?mm agreed with that in terms of soft X-ray radiation yield observed from experiments. This suggests a direct correlation between CS density homogeneity near breakdown and the radiation yield performance. These studies were performed with a linearly increasing voltage time profile as input to the PF device.
Energy Dependence and Scaling Property of Localization Length near a Gapped Flat Band
Ge, Li
2015-01-01
Using a tight-binding model for a one-dimensional Lieb lattice, we show that the localization length near a gapped flat band behaves differently from the typical Urbach tail in a band gap: instead of reducing monotonically as the energy E moves away from the flat band energy E_{FB}, the presence of the flat band causes a nonmonotonic energy dependence of the localization length. This energy dependence follows a scaling property when the energy is within the spread (W) of uniformly distributed diagonal disorder, i.e. the localization length is only a function of (E-E_{FB})/W. Several other lattices are compared to distinguish the effect of the flat band on the localization length, where we eliminate, shift, or duplicate the flat band, without changing the dispersion relations of other bands. Using the top right element of the Green's matrix, we derive an analytical relation between the density of states and the localization length, which shines light on these properties of the latter, including a summation rul...
Safronova, Marianna
Scattering: short--range potentialrange potential incident particles mass: m velocity: v range of the potential V(r ... againdinger equation ... again ( ) 2 2 2 2 2 2 2 ( ) ( ) 2 1 2 2 ( ) 0 E m k E m m k - = = = + = r r r v k V k U U + = + = r r r r r r r #12;3 Wave function at large r &Wave function at large r
Scattering of particles with internal degrees of freedom
Slipushenko, S. V.; Tur, A. V.; Yanovsky, V. V.
2013-08-15
The scattering of particles with a small number of internal degrees of freedom is considered. Billiard formalism is used to study the scattering of two such structurally complex particles. The main scattering characteristics are found. Various types of scattering modes are revealed. In particular, a mode is detected when the velocity of motion of such particles away from each other is higher than their approach velocity before the collision. The scattering of such particles is shown to occur after a finite number of collisions. A generalized Newton law is proposed for the collision of particles with a small number of degrees of freedom, and the form of the effective coefficient of restitution is found.
Anisotropic Elastic Resonance Scattering model for the Neutron Transport equation
Mohamed Ouisloumen; Abderrafi M. Ougouag; Shadi Z. Ghrayeb
2014-11-24
The resonance scattering transfer cross-section has been reformulated to account for anisotropic scattering in the center-of-mass of the neutron-nucleus system. The main innovation over previous implementations is the relaxation of the ubiquitous assumption of isotropic scattering in the center-of-mass and the actual effective use of scattering angle distributions from evaluated nuclear data files in the computation of the angular moments of the resonant scattering kernels. The formulas for the high order anisotropic moments in the laboratory system are also derived. A multi-group numerical formulation is derived and implemented into a module incorporated within the NJOY nuclear data processing code. An ultra-fine energy mesh cross section library was generated using these new theoretical models and then was used for fuel assembly calculations with the PARAGON lattice physics code. The results obtained indicate a strong effect of this new model on reactivity, multi-group fluxes and isotopic inventory during depletion.
Scattering amplitudes for multi-indexed extensions of solvable potentials
Ho, C.-L. [Department of Physics, Tamkang University, Tamsui 251, Taiwan, ROC (China); Lee, J.-C., E-mail: jcclee@cc.nctu.edu.tw [Department of Electrophysics, National Chiao-Tung University, Hsinchu, Taiwan, ROC (China); Sasaki, R. [Center for Theoretical Sciences, National Taiwan University, Taipei, Taiwan, ROC (China); Department of Physics, Shinshu University, Matsumoto 390-8621 (Japan)
2014-04-15
New solvable one-dimensional quantum mechanical scattering problems are presented. They are obtained from known solvable potentials by multiple Darboux transformations in terms of virtual and pseudo virtual wavefunctions. The same method applied to confining potentials, e.g. Pöschl–Teller and the radial oscillator potentials, has generated the multi-indexed Jacobi and Laguerre polynomials. Simple multi-indexed formulas are derived for the transmission and reflection amplitudes of several solvable potentials. -- Highlights: •Scattering amplitudes calculated for infinitely many new solvable potentials. •New scattering potentials obtained by deforming six known solvable potentials. •Multiple Darboux transformations in terms of (pseudo) virtual states employed. •Scattering amplitudes checked to obey the shape invariance relation. •Errors in scattering amplitudes of some undeformed potentials in the literature corrected.
Resonant scattering of surface plasmon polaritons by dressed quantum dots
Huang, Danhong; Cardimona, Dave; Easter, Michelle; Gumbs, Godfrey; Maradudin, A. A.; Lin, Shawn-Yu; Zhang, Xiang
2014-06-23
The resonant scattering of surface plasmon-polariton waves (SPP) by embedded semiconductor quantum dots above the dielectric/metal interface is explored in the strong-coupling regime. In contrast to non-resonant scattering by a localized dielectric surface defect, a strong resonant peak in the spectrum of the scattered field is predicted that is accompanied by two side valleys. The peak height depends nonlinearly on the amplitude of SPP waves, reflecting the feedback dynamics from a photon-dressed electron-hole plasma inside the quantum dots. This unique behavior in the scattered field peak strength is correlated with the occurrence of a resonant dip in the absorption spectrum of SPP waves due to the interband photon-dressing effect. Our result on the scattering of SPP waves may be experimentally observable and applied to spatially selective illumination and imaging of individual molecules.
Yashchuk, V P; Komyshan, A O; Smaliuk, A P; Prygodiuk, O A; Ishchenko, A A; Olkhovyk, L A
2013-12-31
It is shown that reabsorption of the luminescence radiation in the range of its overlapping with the absorption spectrum and the following reemission to a long-wavelength range may noticeably affect the process of stimulated Raman scattering (SRS) in polymethine dyes in multiple scattering media (MSM). This is related to the fact that SRS in such media occurs jointly with the random lasing (RL), which favors SRS and makes up with it a united nonlinear process. Reemission into the long-wavelength spectrum range amplified in MSM causes the RL spectrum to shift to longer wavelengths and initiates the long-wavelength band of RL, in which a main part of the lasing energy is concentrated. This weakens or completely stops the SRS if the band is beyond the range of possible spectral localisation of Stokes lines. This process depends on the efficiency of light scattering, dye concentration, temperature and pump intensity; hence, there exist optimal values of these parameters for obtaining SRS in MSM. (nonlinear optical phenomena)
2002-01-01
by using small angle neutron scattering Winnie Yong †‡ ,technique of small angle neutron scattering has been used tois small angle neutron scattering (SANS). SANS experiments
Quantum phase transitions of the Dirac oscillator in a minimal length scenario
L. Menculini; O. Panella; P. Roy
2014-11-19
We obtain exact solutions of the (2+1) dimensional Dirac oscillator in a homogeneous magnetic field within a minimal length ($\\Delta x_0=\\hbar \\sqrt{\\beta}$), or generalised uncertainty principle (GUP) scenario. This system in ordinary quantum mechanics has a single left-right chiral quantum phase transition (QPT). We show that a non zero minimal length turns on a infinite number of quantum phase transitions which accumulate towards the known QPT when $\\beta \\to 0$. It is also shown that the presence of the minimal length modifies the degeneracy of the states and that in this case there exist a new class of states which do not survive in the ordinary quantum mechanics limit $\\beta \\to 0$.
Infrared length scale and extrapolations for the no-core shell model
Wendt, K A; Papenbrock, T; Sääf, D
2015-01-01
We precisely determine the infrared (IR) length scale of the no-core shell model (NCSM). In the NCSM, the $A$-body Hilbert space is truncated by the total energy, and the IR length can be determined by equating the intrinsic kinetic energy of $A$ nucleons in the NCSM space to that of $A$ nucleons in a $3(A-1)$-dimensional hyper-radial well with a Dirichlet boundary condition for the hyper radius. We demonstrate that this procedure indeed yields a very precise IR length by performing large-scale NCSM calculations for $^{6}$Li. We apply our result and perform accurate IR extrapolations for bound states of $^{4}$He, $^{6}$He, $^{6}$Li, $^{7}$Li. We also attempt to extrapolate NCSM results for $^{10}$B and $^{16}$O with bare interactions from chiral effective field theory over tens of MeV.
Nano-scaled graphene platelets with a high length-to-width aspect ratio
Zhamu, Aruna (Centerville, OH); Guo, Jiusheng (Centerville, OH); Jang, Bor Z. (Centerville, OH)
2010-09-07
This invention provides a nano-scaled graphene platelet (NGP) having a thickness no greater than 100 nm and a length-to-width ratio no less than 3 (preferably greater than 10). The NGP with a high length-to-width ratio can be prepared by using a method comprising (a) intercalating a carbon fiber or graphite fiber with an intercalate to form an intercalated fiber; (b) exfoliating the intercalated fiber to obtain an exfoliated fiber comprising graphene sheets or flakes; and (c) separating the graphene sheets or flakes to obtain nano-scaled graphene platelets. The invention also provides a nanocomposite material comprising an NGP with a high length-to-width ratio. Such a nanocomposite can become electrically conductive with a small weight fraction of NGPs. Conductive composites are particularly useful for shielding of sensitive electronic equipment against electromagnetic interference (EMI) or radio frequency interference (RFI), and for electrostatic charge dissipation.
Ashkenazy, Yossi "Yosef"
Fourier analysis of light scattered by elongated scatterers Zeev Schiffer, Yosef Ashkenazy, Reuven in the Fourier plane, the size and structure of a single cell is deter- mined by means of a particular inverse Fourier trans- form. However, using such a transform to determine the structural parameters of an entire
Walker, D. Greg
Coupled QuantumCoupled Quantum--ScatteringScattering Modeling of the ThermoelectricModeling of the Thermoelectric Properties of Si/Ge/SiProperties of Si/Ge/Si Quantum Well SuperlatticesQuantum Well Superlattices Phonons Si SiGe 2 S T ZT = · Quantum well superlattices proposed to improve thermoelectric figure
Synchrotron X-ray Scattering Studies of Rapidly Evolving Nanoscale Interfacial Systems /
Dai, Yeling
2013-01-01
Stanley. X-ray and neutron scattering from rough surfaces.Stanley. X-ray and neutron scattering from rough surfaces.grazing incidence x-ray and neutron scattering from ordered
Analysis of Order Formation in Block Copolymer Thin Films Using Resonant Soft X-Ray Scattering
Virgili, Justin M.; Tao, Yuefei; Kortright, Jeffrey B.; Balsara, Nitash P.; Segalman, Rachel A.
2006-01-01
Methods of X-Ray and Neutron Scattering in Polymer Science.µ t for X-ray and neutron scattering experiments is unity;18 In classical scattering of light, X-rays or neutrons the
X-ray scattering studies of structure and dynamics of surfaces and interfaces of polymeric liquids
Jiang, Zhang
2007-01-01
Evanescent X-ray and Neutron Scattering. Springer-Verlag,Methods of X-ray and neutron scattering in polymer science.Stanley. X-ray and neutron scattering from rough surfaces.
Determination of the length and compass orientation of hydraulic fractures by pulse testing
Manohar, Madan Mohan
1984-01-01
S3HAIDVHi OIlflVHOAH i0 NOIlVIN3IHO SSVHWOO QNV HlBN31 3Wl iO NOIlVNIWH3l30 DETERMINATION OF THE LENGTH AND COMPASS ORIENTATION OF HYDRAULIC FRACTURES BY PULSE TESTING A Thesis by MADAN MOHAN MANOHAR Approved as to Style and Content by: Wi... liam J. Lee (Ch ai rman of Commi t tee ) Le a M. Je Member) Richard A. Morse (Member) D. Yon Gonten ( d of Department) December 1984 ABSTRACT Determination of the Length and Compass Drientat1on of Hydraulic Fractures by Pulse Testing...
Huang, David M.; Chandler, David
2000-04-01
The Lum-Chandler-Weeks theory of hydrophobicity [J. Phys. Chem. 103, 4570 (1999)] is applied to treat the temperature dependence of hydrophobic solvation in water. The application illustrates how the temperature dependence for hydrophobic surfaces extending less than 1nm differs significantly from that for surfaces extending more than 1nm. The latter is the result of water depletion, a collective effect, that appears at length scales of 1nm and larger. Due to the contrasting behaviors at small and large length scales, hydrophobicity by itself can explain the variable behavior of protein folding.
Adam J. Mullavey; Bram J. J. Slagmolen; John Miller; Matthew Evans; Peter Fritschel; Daniel Sigg; Sam J. Waldman; Daniel A. Shaddock; David E. McClelland
2011-12-14
Residual motion of the arm cavity mirrors is expected to prove one of the principal impediments to systematic lock acquisition in advanced gravitational-wave interferometers. We present a technique which overcomes this problem by employing auxiliary lasers at twice the fundamental measurement frequency to pre-stabilise the arm cavities' lengths. Applying this approach, we reduce the apparent length noise of a 1.3 m long, independently suspended Fabry-Perot cavity to 30 pm rms and successfully transfer longitudinal control of the system from the auxiliary laser to the measurement laser.
Tests of the Gravitational Inverse-Square Law below the Dark-Energy Length Scale
D. J. Kapner; T. S. Cook; E. G. Adelberger; J. H. Gundlach; B. R. Heckel; C. D. Hoyle; H. E. Swanson
2006-11-14
We conducted three torsion-balance experiments to test the gravitational inverse-square law at separations between 9.53 mm and 55 micrometers, probing distances less than the dark-energy length scale $\\lambda_{\\rm d}=\\sqrt[4]{\\hbar c/\\rho_{\\rm d}}\\approx 85 \\mu$m. We find with 95% confidence that the inverse-square law holds ($|\\alpha| \\leq 1$) down to a length scale $\\lambda = 56 \\mu$m and that an extra dimension must have a size $R \\leq 44 \\mu$m.
Minimal Length and the Existence of Some Infinitesimal Quantities in Quantum Theory and Gravity
A. E. Shalyt-Margolin
2014-12-10
In this work it is demonstrated that, provided a theory involves a minimal length, this theory must be free from such infinitesimal quantities as infinitely small variations in surface of the holographic screen, its volume, and entropy. The corresponding infinitesimal quantities in this case must be replaced by the "minimal variations possible" -- finite quantities dependent on the existent energies. As a result, the initial low-energy theory (quantum theory or general relativity) inevitably must be replaced by a minimal-length theory that gives very close results but operates with absolutely other mathematical apparatus.
Effect of core length on laboratory displacement of oil by CO? in sandstone
Chan, Kenneth Yun-Kwong
1974-01-01
EXPECT OP CORE LENGTH ON LABORATORY DISPLACEMENT OP OIL BY C02 IN SANDSTONE A Thesis by KENNETH YUN KWONG CHAN Submitted to the Graduate College of Texas khM University in partial fulfillment of the requirement for the degree of MASTER OP... SCIENCE August 1974 Major Subject: Petroleum Engineering EPACT OP CORE LENGTH ON LABORATORY DISPLACEMENT Oy OIL BY COR IN SANDSTONE A Thesis by KENNETH YUN KWONG CHAN Approved as to style and content by: a an o omm ee ea o Department ember Mem...
He, Lilin [ORNL; Mavila Chathoth, Suresh [ORNL; Melnichenko, Yuri B [ORNL; Presser, Volker [Drexel University; Mcdonough, John [Drexel University; Gogotsi, Yury G. [Drexel University
2011-01-01
We used small-angle neutron scattering (SANS) and neutron contrast variation to study the structure of four nanoporouscarbons prepared by thermo-chemical etching of titanium carbide TiC in chlorine at 300, 400, 600, and 800 C with pore diameters ranging between -4 and -11 {angstrom}. SANS patterns were obtained from dry samples and samples saturated with deuterium oxide (D{sub 2}O) in order to delineate origin of the power law scattering in the low Q domain as well as to evaluate pore accessibility for D{sub 2}O molecules. SANS cross section of all samples was fitted to Debye-Anderson-Brumberger (DAB), DAB-Kirste-Porod models as well as to the Guinier and modified Guinier formulae for cylindrical objects, which allowed for evaluating the radii of gyration as well as the radii and lengths of the pores under cylindrical shape approximation. SANS data from D{sub 2}O-saturated samples indicate that strong upturn in the low Q limit usually observed in the scattering patterns from microporous carbon powders is due to the scattering from outer surface of the powder particles. Micropores are only partially filled with D{sub 2}O molecules due to geometrical constraints and or partial hydrophobicity of the carbon matrix. Structural parameters of the dry carbons obtained using SANS are compared with the results of the gas sorption measurements and the values agree for carbide-derived carbons (CDCs) obtained at high chlorination temperatures (>600 C). For lower chlorination temperatures, pore radii obtained from gas sorption overestimate the actual pore size as calculated from SANS for two reasons: inaccessible small pores are present and the model-dependent fitting based on density functional theory models assumes non-spherical pores, whereas SANS clearly indicates that the pore shape in microporous CDC obtained at low chlorination temperatures is nearly spherical.
Kontar, Eduard P.; Bian, Nicolas H.; Emslie, A. Gordon; Vilmer, Nicole E-mail: emslieg@wku.edu
2014-01-10
Recent observations from RHESSI have revealed that the number of non-thermal electrons in the coronal part of a flaring loop can exceed the number of electrons required to explain the hard X-ray-emitting footpoints of the same flaring loop. Such sources cannot, therefore, be interpreted on the basis of the standard collisional transport model, in which electrons stream along the loop while losing their energy through collisions with the ambient plasma; additional physical processes, to either trap or scatter the energetic electrons, are required. Motivated by this and other observations that suggest that high-energy electrons are confined to the coronal region of the source, we consider turbulent pitch-angle scattering of fast electrons off low-frequency magnetic fluctuations as a confinement mechanism, modeled as a spatial diffusion parallel to the mean magnetic field. In general, turbulent scattering leads to a reduction of the collisional stopping distance of non-thermal electrons along the loop, and hence to an enhancement of the coronal hard X-ray source relative to the footpoints. The variation of source size L with electron energy E becomes weaker than the quadratic behavior pertinent to collisional transport, with the slope of L(E) depending directly on the mean free path ? associated with the non-collisional scattering mechanism. Comparing the predictions of the model with observations, we find that ? ? (10{sup 8}-10{sup 9}) cm for ?30 keV, less than the length of a typical flaring loop and smaller than, or comparable to, the size of the electron acceleration region.
LeClair, Robert J.; Boileau, Michel M.; Wang Yinkun [Department of Physics and Astronomy, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario, P3E 2C6 (Canada) and Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario, P3E 2C6 (Canada); Department of Physics and Astronomy, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario, P3E 2C6 (Canada); Department of Physics and Astronomy, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario, P3E 2C6 (Canada)
2006-04-15
The goal of this work is to develop a technique to measure the x-ray diffraction signals of breast biopsy specimens. A biomedical x-ray diffraction technology capable of measuring such signals may prove to be of diagnostic use to the medical field. Energy dispersive x-ray diffraction measurements coupled with a semianalytical model were used to extract the differential linear scattering coefficients [{mu}{sub s}(x)] of breast tissues on absolute scales. The coefficients describe the probabilities of scatter events occurring per unit length of tissue per unit solid angle of detection. They are a function of the momentum transfer argument, x=sin({theta}/2)/{lambda}, where {theta}=scatter angle and {lambda}=incident wavelength. The technique was validated by using a 3 mm diameter 50 kV polychromatic x-ray beam incident on a 5 mm diameter 5 mm thick sample of water. Water was used because good x-ray diffraction data are available in the literature. The scatter profiles from 6 deg. to 15 deg. in increments of 1 deg. were measured with a 3 mmx3 mmx2 mm thick cadmium zinc telluride detector. A 2 mm diameter Pb aperture was placed on top of the detector. The target to detector distance was 29 cm and the duration of each measurement was 10 min. Ensemble averages of the results compare well with the gold standard data of A. H. Narten [''X-ray diffraction data on liquid water in the temperature range 4 deg. C-200 deg. C, ORNL Report No. 4578 (1970)]. An average 7.68% difference for which most of the discrepancies can be attributed to the background noise at low angles was obtained. The preliminary measurements of breast tissue are also encouraging.