4,090 results
Search Results
2. Quasiclassical approximation in the theory of scattering of polarized atoms
- Author
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Dashevskaya, E. I., Nikitin, E. E., Araki, H., editor, Beig, R., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R. L., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Lehr, Sabine, editor, Jungmann, Klaus Peter, editor, Kowalski, Joachim, editor, Reinhard, Irene, editor, and Träger, Frank, editor
- Published
- 1997
- Full Text
- View/download PDF
3. Recent Progress in the Study of Heavy-Ion Resonances
- Author
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Betts, R. R., Lilley, J. S., editor, and Nagarajan, M. A., editor
- Published
- 1985
- Full Text
- View/download PDF
4. Recent high energy electron investigations at Stanford University
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Buchanan, C. D., Collard, H., Crannell, C., Frosch, R., Griffy, T. A., Hofstadter, R., Hughes, E. B., Nöldeke, G. K., Oakes, R. J., van Oostrum, K. J., Rand, R. E., Suelzle, L., Yearian, M. R., Clark, B. C., Herman, R., Ravenhall, D. G., Höhler, Gerhard, Fujimori, Atsushi, Kühn, Johann, Müller, Thomas, Steiner, Frank, Trümper, Joachim E., Wölfle, Peter, and Woggon, Ulrike
- Published
- 1965
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- View/download PDF
5. Theory of strong interactions of elementary particles in the GeV region
- Author
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Van Hove, L., Höhler, Gerhard, Fujimori, Atsushi, Kühn, Johann, Müller, Thomas, Steiner, Frank, Trümper, Joachim E., Wölfle, Peter, and Woggon, Ulrike
- Published
- 1965
- Full Text
- View/download PDF
6. Flavor Symmetry of Hydrogen Atoms Potentially Affecting the Proton Radius Deduced from the Electron-Hydrogen Scattering.
- Author
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Oks, Eugene
- Subjects
HYDROGEN atom ,ATOMIC physics ,ATOMIC hydrogen ,QUANTUM chromodynamics ,ATOMIC spectroscopy ,FLAVOR ,GLUONS ,ELASTIC scattering - Abstract
Precise knowledge of such fundamental quantity as the proton charge radius r
p is extremely important both for the quantum chromodynamics (for quark-gluon structure) and for atomic physics (for atomic hydrogen spectroscopy). Yet the ambiguity in measuring rp persists for over a dozen of years by now—from the time when in 2010 the muonic hydrogen spectroscopy experiment yielded rp ≈ 0.84 fm in contrast to the form factor experiment by the Mainz group that produced rp ≈ 0.88 fm. Important was that this difference corresponded to about seven standard deviations and therefore was inexplicable. In the intervening dozen of years, more experiments of various kinds were performed in this regard. Nevertheless, the controversy remains, which is why several different types of new experiments are being prepared for measuring rp . In one of our previous papers, we pointed out the factor that was never taken into account by the corresponding research community: the flavor symmetry of electronic hydrogen atoms, whose existence was confirmed by four kinds of atomic or molecular experiments and also evidenced by two kinds of astrophysical observations. Specifically, in that paper there was discussed the possible presence of the second flavor of muonic hydrogen atoms (in the corresponding experimental gas) and its effect on the shift of the ground state of muonic hydrogen atoms due to the proton finite size. In the present paper we analyze the effect of the flavor symmetry of electronic hydrogen atoms on the corresponding elastic scattering cross-section and on the proton charge radius rp deduced from the cross-section. As an example, we use our analytical results for reconciling two distinct values of rp obtained in different elastic scattering experiments: 0.88 fm and 0.84 fm (which is by about 4.5% smaller than 0.88 fm). We show that if the ratio of the second flavor of hydrogen atoms to the usual hydrogen atoms in the experimental gas would be about 0.3, then the extraction of rp from the corresponding cross-section would yield by about 4.5% smaller value of rp compared to its true value. We also derive the corresponding general formulas that can be used for interpreting the future electronic and muonic experiments. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
7. Electron Scattering from the Proton
- Author
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Hofstadter, Robert, McAllister, Robert W., van der Merwe, Alwyn, editor, Noz, M. E., editor, and Kim, Y. S., editor
- Published
- 1988
- Full Text
- View/download PDF
8. Compton scattering: the investigation of electron momentum distributions. [review papers]
- Author
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Williams, B [ed.]
- Published
- 1977
9. Clustering phenomena in nuclei: II. Invited lectures and contributed papers from the second international conference on clustering phenomena in nuclei, College Park, Maryland, 21--25 April 1975
- Author
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Wallace, S [eds.]
- Published
- 1975
10. Comment on paper of M. G. Bowler
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Rosenfeld, A
- Published
- 1974
11. Electron distribution function in a nonuniform, magnetized, weakly photoionized gas: application to a model ionosphere. Environmental research papers
- Author
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Jasperse, J
- Published
- 1975
12. The effect of several configuration interaction target states on the elastic scattering of low-energy electrons by complex atoms. Physical sciences research papers
- Author
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Smith, E
- Published
- 1975
13. RATIO OF THE DIFFUSION COEFFICIENT TO THE MOBILITY COEFFICIENT FOR ELECTRON IN He, A, N*SUB 2/, H*SUB 2/, D*SUB 2/, CO, AND CO*SUB 2/ AT LOW TEMPERATURES AND LOW E/P (WITH TABULATED DATA). Scientific Paper 62-908-113-P6. Technical Report No. 12
- Author
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Parker, Jr, J
- Published
- 1962
14. COMMENTS OF A PAPER ON ELASTICALLY SCATTERED RECOIL NUCLEI IN SOLID STATE DETECTORS.
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Walker, R
- Published
- 1969
15. Reactor neutrino physics potentials of cryogenic pure-CsI crystal.
- Author
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Wang, Lei, Li, Guanda, Yu, Zeyuan, Liang, Xiaohua, Wang, Tian'an, Liu, Fang, Sun, Xilei, Guo, Cong, Zhang, Xin, Lei, Yu, and Chen, Yuede
- Subjects
SCINTILLATION counters ,NEUTRINOS ,CRYOELECTRONICS ,PHYSICS ,NEUTRINO scattering ,CRYSTALS ,ELASTIC scattering - Abstract
This paper presents a world-leading scintillation light yield among inorganic crystals measured from a 0.5 kg pure-CsI detector operated at 77 Kelvin. Scintillation photons were detected by two 2-inch Hamamatsu SiPM arrays equipped with cryogenic front-end electronics. Benefiting the light yield enhancement of pure-CsI at low temperatures and the high photon detection efficiency of SiPM, a light yield of 30.1 photoelectrons per keV energy deposit was obtained for X-rays and γ -rays with energies from 5.9 to 59.6 keV. Instrumental and physical effects in the light yield measurement are carefully analyzed. This is the first stable cryogenic operation of kg-scale pure-CsI crystal readout by SiPM arrays at liquid nitrogen temperatures for several days. The world-leading light yield opens a door for the usage of pure-CsI crystal in several fields, particularly in detecting the coherent elastic neutrino-nucleus scattering of reactor neutrinos. The potential of using pure-CsI crystals in neutrino physics is discussed in the paper. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
16. Multiple scattering and resolution effects in small-angle neutron scattering experiments calculated and corrected by the software package MuScatt
- Author
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Sebastian Jaksch, Henrich Frielinghaus, and Vitaliy Pipich
- Subjects
Physics ,Elastic scattering ,small-angle neutron scattering ,SANS ,Scattering ,resolution ,Neutron scattering ,Inelastic scattering ,Research Papers ,Small-angle neutron scattering ,General Biochemistry, Genetics and Molecular Biology ,multiple scattering ,Computational physics ,ddc ,Wavelength ,corrections ,ddc:540 ,Deconvolution ,Chandrasekhar limit - Abstract
Calculations and desmearing of different multiple scattering effects for the small-angle scattering technique using the software package MuScatt are presented., This article deals with multiple scattering effects that are important for the method of small-angle neutron scattering (SANS). It considers three channels for the coherent elastic, the incoherent elastic and the incoherent inelastic scattering processes. The first channel contains the desired information on the experiment. Its multiple scattering effects can be desmeared, as shown in the later sections of the article. The other two channels display a nearly constant background as a function of the scattering angle. The incoherent elastic scattering is treated by the theory of Chandrasekhar, allowing for multiple scattering even at large scattering angles. The transfer to a single representative thermalized wavelength by the inelastic scattering – as a simplification – is assumed to happen by a single scattering event. Once the transition to this altered wavelength has happened, further incoherent multiple scattering is considered. The first part of the paper deals with the multiple scattering effects of light water. In the later part of the article, deconvolution algorithms for multiple scattering and instrumental resolution of the elastic coherent signal as implemented in the program MuScatt are described. All of these considerations are interesting for both reactor-based instruments with velocity selectors and time-of-flight SANS instruments and may improve the reliability of the data treatment.
- Published
- 2021
17. Discontinuous Dynamics of a 2-DOF Friction Oscillator with Rigid and Elastic Composite Constraints.
- Author
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Cheng, Xinyu, Fan, Jinjun, and Li, Jianping
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MULTIBODY systems ,PERIODIC motion ,MOTION ,VIBRATION (Mechanics) ,SWITCHING theory ,EQUATIONS of motion ,ELASTIC scattering ,DRY friction ,SLIDING friction - Abstract
Purpose: The switching of motion states and grazing/sliding motion for an oscillator are typical dynamic phenomena in some discontinuous/non-smooth dynamical systems such as friction/vibro-impact systems with clearance. This work describes the behavior of discontinuous dynamics for a two-degree-of-freedom (2-DOF) frictional collision system with intermediate rigid constraint and unilateral elastic collision under periodic excitation by flow switching theory, where this kind of system considered in this paper can better reflect the actual working conditions of a class of mechanical vibration systems and is few researched at present. Methods: First, the physical model studied in this paper is introduced and analyzed in depth (such as motion state, motion equation, etc.). Second, based on the discontinuity/nonsmoothness of oscillator's movement, the absolute and relative phase planes of oscillator's movement are divided into multiple dynamic domains and dynamic boundaries such that the vector field in each dynamic domain is continuous. Third, according to the difference between the static friction coefficient and the dynamic friction coefficient of the system, the flow barrier which is generated on the velocity boundary and prevents the boundary flow from flowing to the domain is studied. Results: By means of the vector field and G-function, the criteria for the switching of each state of motion on the separation boundaries are obtained. And then, the conversions of some typical movements are more intuitively demonstrated through numerical simulation based on MATLAB software. A multi-body dynamics model of this 2-DOF system is developed in MSC Adams to help us visualize the actual dynamics behavior under real dimensional system parameters and compare it with the foregoing numerical simulation for a group of periodic motion data, and the results are nearly consistent. Conclusion: This work further improves the flow switching theory and brings a theoretical reference for multi-constrained mechanical systems. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
18. Time-domain analysis for the scattering of plane elastic waves in half-space with an open trench.
- Author
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Liang, Yuwang, Zhou, Fengxi, Cao, Xiaolin, Wang, Liye, Zhu, Shunwang, and Zhou, Zhixiong
- Subjects
ELASTIC waves ,PLANE wavefronts ,TIME-domain analysis ,ELASTIC wave propagation ,ELASTIC scattering ,BOUNDARY element methods ,TRENCHES ,FINITE element method - Abstract
In this paper, the scattering and vibration isolation of elastic waves from the open trench are analyzed and discussed in the time domain using the scaled boundary finite element method (SBFEM). Based on the theory of soil-structure interaction, the site with an open trench is decomposed into a near-field system and an infinite far-field system. The quadtree domain decomposition technique is employed for SBFEM mesh discretization of the near-field. The far-field is rigorously modeled by the displacement unit impulse response matrix. The obliquely plane elastic wave from the far-field is converted into a traction force acting on the near/far-field boundary. The time-space domain numerical model is established for elastic wave propagation in half-space with an open trench. Finally, through numerical examples to verify the effectiveness of the method of this paper, and parametric analyze the effect law of the incidence angle and the trench depth, etc., on the vibration isolation performance. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
19. Low energy elastic and inelastic scattering of positrons from formic acid.
- Author
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Stevens, D, Datar, Aaditya, Cheong, Z, and Sullivan, J P
- Subjects
SCATTERING (Physics) ,INELASTIC scattering ,ELECTRON scattering ,ELASTIC scattering ,FORMIC acid ,DIFFERENTIAL cross sections ,ELECTRONIC excitation - Abstract
This paper presents a detailed study of low energy positron scattering from formic acid, examining elastic scattering, electronic excitation and ionisation processes. Through detailed comparisons with previous experimental and theoretical data, it is clear that the picture for positron scattering from this target remains incomplete, with significant disagreement between experiment and theory in the comparisons of differential cross section data. Calculations of elastic electron scattering are unexpectedly in better agreement with the positron scattering experiments, and give some hints as to potential areas for improvement in the modelling of scattering for targets which tend to be dominated by dipole interactions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
20. Near-field imaging method for interior inverse elastic scattering problem.
- Author
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Zeng, Fang, Wang, Jiajia, Zhou, Shuang, and Dong, Haiyun
- Subjects
- *
ELASTIC scattering , *HELMHOLTZ equation , *COORDINATE transformations , *BOUNDARY value problems , *INVERSE problems , *POWER series , *LONGITUDINAL waves - Abstract
The interior inverse elastic scattering problem is considered in this paper. The scattering in the cavity is illuminated by an time-harmonic elastic point source at fixed frequency. The boundary of the cavity is assumed to be a small and smooth perturbation of some circle. In this paper, we are interested in the reconstruction of the boundary according to the measured data on a closed curve inside the cavity. In implementation, we split the displacement field into compressional and shear waves by the Helmholtz decomposition. Then we use coordinate transformation, power series expansion based on perturbed parameters and Fourier expansion of corresponding power series coefficients to simplify the original boundary value problem to a successive sequence of one-dimensional boundary value problem. We linearize the inverse problem by eliminating the higher-order terms in the power series expansion; and design a reconstruction algorithm by the explicit relationship between the Fourier coefficients of the boundary function and the total field. In order to obtain better resolution, we also use a nonlinear correction method in the numerical experiments. The numerical results have shown the effectiveness and the stableness of the proposed method. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
21. Selected bibliography on atomic collisions: Data collections, bibliographies, review articles, books, and papers of particular tutorial value
- Author
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Steven T. Manson, M. R. Flannery, Earl W. McDaniel, and E.W. Thomas
- Subjects
Elastic scattering ,Nuclear and High Energy Physics ,Range (particle radiation) ,Chemistry ,Electron ,Collision ,Atomic and Molecular Physics, and Optics ,Nuclear physics ,Bibliography ,Nuclear force ,Particle ,Atomic physics ,Nuclear Experiment ,Transport phenomena - Abstract
This bibliography deals mainly with binary and ternary collisions involving electrons, photons, and heavy particles (i.e., atoms, molecules, and ions). The energy range covered for each kind of collision is such that the interactions might be described as electronic, atomic, or chemical—higher-energy collisions involving nuclear forces are not treated. Also covered are particle and photon impact on surfaces, the passage of particles and radiation through bulk matter, and transport phenomena in gases. Practically all of the references cited are data compilations, other bibliographies, review articles, or books. The main objective is to provide easy access to atomic collision data, although some references are included principally for their tutorial value.
- Published
- 1985
22. Regge Poles in the Scattering of Particles of Unequal Mass. Remark on a Paper of Freedman and Wang
- Author
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Loyal Durand
- Subjects
Scattering amplitude ,Physics ,Elastic scattering ,Scattering ,Quantum mechanics ,Crossing ,General Physics and Astronomy ,Scattering length ,Scattering theory ,Mott scattering ,Mathematical physics ,S-matrix - Published
- 1967
23. Monte Carlo simulation of coherently scattered photons based on the inverse-sampling technique
- Author
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Ying Liang, Bradley J. Nartowt, Wazir Muhammad, Jun Deng, and Gregory R. Hart
- Subjects
Physics ,Elastic scattering ,Photon ,Anomalous scattering ,Scattering ,Monte Carlo method ,Complex system ,010403 inorganic & nuclear chemistry ,Condensed Matter Physics ,Research Papers ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Computational physics ,Inorganic Chemistry ,Matrix (mathematics) ,symbols.namesake ,Structural Biology ,symbols ,General Materials Science ,Physical and Theoretical Chemistry ,Rayleigh scattering - Abstract
The acceptance–rejection technique has been widely used in several Monte Carlo simulation packages for Rayleigh scattering of photons. However, the models implemented in these packages might fail to reproduce the corresponding experimental and theoretical results. The discrepancy is attributed to the fact that all current simulations implement an elastic scattering model for the angular distribution of photons without considering anomalous scattering effects. In this study, a novel Rayleigh scattering model using anomalous scattering factors based on the inverse-sampling technique is presented. Its performance was evaluated against other simulation algorithms in terms of simulation accuracy and computational efficiency. The computational efficiency was tested with a general-purpose Monte Carlo package named Particle Transport in Media (PTM). The evaluation showed that a Monte Carlo model using both atomic form factors and anomalous scattering factors for the angular distribution of photons (instead of the atomic form factors alone) produced Rayleigh scattering results in closer agreement with experimental data. The comparison and evaluation confirmed that the inverse-sampling technique using atomic form factors and anomalous scattering factors exhibited improved computational efficiency and performed the best in reproducing experimental measurements and related scattering matrix calculations. Furthermore, using this model to sample coherent scattering can provide scientific insight for complex systems.
- Published
- 2020
24. Comparative study of α - α interaction potentials constructed using various phenomenological models.
- Author
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AWASTHI, Ayushi and SASTRI, O. S. K. S.
- Subjects
COULOMB potential ,ELASTIC scattering ,COMPARATIVE studies ,MATHEMATICAL functions ,RUNGE-Kutta formulas ,MORSE theory - Abstract
In this paper, we have made a comparative study of α-α scattering using different phenomenological models like Morse, double Gaussian, double Hulthén, Malfliet-Tjon, and double exponential for the nuclear interaction, and atomic Hulthén as the screened Coulomb potential. The phase equations for S, D, and G channels have been numerically solved using the 5
th -order Runge-Kutta method to compute scattering phase shifts (SPS) for the elastic scattering region consisting of energies up to 25.5 MeV. The model parameters in each of the chosen potentials were varied in an iterative fashion to minimize the mean absolute percentage error (MAPE) between simulated and expected SPS. A comparative analysis revealed that all the phenomenological models result in exactly similar optimized potentials with closely matching MAPE values for S, D, and G states. One can conclude that any mathematical function that can capture the basic features of two-body interaction will always guide the construction of optimized potentials correctly. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
25. How Fast are Elastic Domino Waves?
- Author
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Ding, Daniel, Lau, Clement, Westerhof, Jorrit, Hoeven, Lotte van der, Kampstra, Lieke, Beek, Patrick van der, and Ostanin, Igor
- Subjects
ELASTIC waves ,ELASTIC scattering ,DISCRETE element method - Abstract
The paper is concerned with the problem of toppling propagation velocity in elastic, domino-like mechanical systems. We build on the work of Efthimiou and Johnson, who developed the theory of perfectly elastic collisions of thin rigid dominoes on a frictional foundation. This theory has been criticised for the lack of correspondence with the experimental observations, in particular, prediction of infinite propagation velocity for zero spacing between dominoes, as well as the inability to represent the collective nature of collisions in real domino systems. In our work we consider a more realistic scenario of dominoes of finite stiffness and obtain a theory of fast elastic domino waves, taking into account a limit velocity of the perturbation propagation in the system of dominoes. Moreover, finite collision time allows to extract dynamic quantities of collisions and establish upper and lower borders for domino separations where the theory could still be applied. Our discrete element simulations support our theoretical findings and shed light on the nature of collective interactions in the nearly-elastic domino chains. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. Dip-Bump Structure in Proton's Single Diffractive Dissociation at the Large Hadron Collider.
- Author
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Jenkovszky, László, Schicker, Rainer, and Szanyi, István
- Subjects
DIFFRACTIVE scattering ,LARGE Hadron Collider ,NUCLEON-nucleon scattering ,PROTONS ,MOMENTUM transfer ,HADRON colliders ,ELASTIC scattering - Abstract
By extending the dipole Pomeron (DP) model, successful in describing elastic nucleon–nucleon scattering, to proton single diffractive dissociation (SD), we predict a dip-bump structure in the squared four-momentum transfer (t) distribution of proton's SD. Structures in the t distribution of single diffractive dissociation are predicted around t = − 4 GeV 2 at LHC energies in the range of 3 GeV 2 ≲ | t | ≲ 7 GeV 2 . Apart from the dependence on s (total energy squared) and t (squared momentum transfer), we predict also a dependence on missing masses. We include the minimum set of Regge trajectories, namely the Pomeron and the Odderon, indispensable at the LHC. Further generalization, e.g., by the inclusion of non-leading Regge trajectories, is straightforward. The present model contains two types of Regge trajectories: those connected with t -channel exchanges (the Pomeron, the Odderon, and non-leading (secondary) reggeons) appearing at small and moderate − t , where they are real and nearly linear, as well as direct-channel trajectories α (M 2) related to missing masses. In this paper, we concentrate on structures in t neglecting (for the time being) resonances in M 2 . [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. RESONANT MODAL APPROXIMATION OF TIME-DOMAIN ELASTIC SCATTERING FROM NANO-BUBBLES IN ELASTIC MATERIALS.
- Author
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BOCHAO CHEN, YIXIAN GAO, YONG LI, and HONGYU LIU
- Subjects
ELASTIC scattering ,SCATTERING (Physics) ,FINITE fields ,ACOUSTIC field ,COMPOSITE materials - Abstract
This paper is devoted to establishing the resonant modal expansion of the lowfrequency part of the scattered field for acoustic bubbles embedded in elastic materials. Due to the nanobubble with damping, the Minnaert resonance can be induced at certain discrete resonant frequencies, which forms the fundamental basis of effectively constructing elastic metamaterials via the composite material theory. There are two major contributions in this work. First, we ansatz a special form of the density, approximate the incident field with a finite number of modes, and then obtain an expansion with a finite number of modes for the acoustic-elastic wave scattering in the time-harmonic regime. Second, we show that the low-frequency part of the scattered field in the time domain can be well approximated by using the modal expansion with sharp error estimates. Interestingly, we find that the 0th mode is the main contribution to reconstruct the information of the low-frequency part of the scattered field. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. New approach on the study of operator matrix.
- Author
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Marzouk, Ines and Walha, Ines
- Subjects
TRANSPORT equation ,ELASTIC scattering ,NEUTRON transport theory ,DIFFERENTIAL equations ,SCHUR complement ,MATRICES (Mathematics) ,SCHRODINGER operator - Abstract
In the present paper, a new technique is presented to study the problem of invertibility of unbounded block 3 × 3 operator matrices defined with diagonal domain. Sufficient criteria are established to guarantee our interest and to prove some interaction between such a model of an operator matrix and its diagonal operator entries. The effectiveness of the proposed new technique is shown by a physical example of an integro differential equation named the neutron transport equation with partly elastic collision operators. In particular, the obtained results answer the question in [H. Zguitti, A note on Drazin invertibility for upper triangular block operators, Mediterr. J. Math. 10 2013, 3, 1497–1507] and the conjecture in [A. Bahloul and I. Walha, Generalized Drazin invertibility of operator matrices, Numer. Funct. Anal. Optim. 43 2022, 16, 1836–1847]. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
29. Comment on Paper of M. G. Bowler
- Author
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A. H. Rosenfeld
- Subjects
Physics ,Elastic scattering ,Nuclear physics ,Isospin ,Quantum electrodynamics - Published
- 1974
30. Simulations of foil-based spin-echo (modulated) small-angle neutron scattering with a sample using McStas
- Author
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Erik Knudsen, Wim G. Bouwman, Peter Kjær Willendrup, and Linda Udby
- Subjects
Larmor precession ,Physics ,Elastic scattering ,Scattering ,polarized neutrons ,Neutron scattering ,Small-angle neutron scattering ,Research Papers ,General Biochemistry, Genetics and Molecular Biology ,Computational physics ,Monte Carlo simulations ,small-angle scattering ,Spin echo ,Neutron ,Small-angle scattering ,spin-echo methods - Abstract
Simulations of a foil-based spin-echo small-angle neutron scattering instrument are performed and agree with analytical calculations. The simulation tools for polarization manipulation can be used to optimally design new spin-echo instruments., For the further development of spin-echo techniques to label elastic scattering it is necessary to perform simulations of the Larmor precession of neutron spins in a magnetic field. The details of some of these techniques as implemented at the reactor in Delft are simulated. First, the workings of the magnetized foil flipper are simulated. A full virtual spin-echo small-angle neutron scattering instrument is built and tested without and with a realistic scattering sample. It is essential for these simulations to have a simulated sample that also describes the transmitted beam of unscattered neutrons, which usually is not implemented for the simulation of conventional small-angle neutron scattering (SANS) instruments. Finally, the workings of a spin-echo modulated small-angle neutron scattering (SEMSANS) instrument are simulated. The simulations are in good agreement with theory and experiments. This setup can be extended to include realistic magnetic field distributions to fully predict the features of future Larmor labelling elastic-scattering instruments. Configurations can now be simulated for more complicated combinations of SANS with SEMSANS.
- Published
- 2021
31. Experimental validation of a spectroscopic Monte Carlo light transport simulation technique and Raman scattering depth sensing analysis in biological tissue
- Author
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Rajeev Agarwal, Guillaume Sheehy, Juliette Selb, Alireza Akbarzadeh, Frederic Leblond, Jessie R. Weber, and Ehsan Edjlali
- Subjects
Paper ,Materials science ,Optical fiber ,Monte Carlo method ,elastic scattering ,Biomedical Engineering ,Inelastic scattering ,Spectrum Analysis, Raman ,01 natural sciences ,Light scattering ,law.invention ,010309 optics ,Biomaterials ,symbols.namesake ,Optics ,law ,0103 physical sciences ,Fiber Optic Technology ,Scattering, Radiation ,Computer Simulation ,tissue optics ,General ,Monte Carlo simulation ,Elastic scattering ,Phantoms, Imaging ,business.industry ,Scattering ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,metrology ,Raman spectroscopy ,symbols ,fluorescence ,business ,Monte Carlo Method ,Raman scattering - Abstract
Significance: Raman spectroscopy (RS) applied to surgical guidance is attracting attention among scientists in biomedical optics. Offering a computational platform for studying depth-resolved RS and probing molecular specificity of different tissue layers is of crucial importance to increase the precision of these techniques and facilitate their clinical adoption. Aim: The aim of this work was to present a rigorous analysis of inelastic scattering depth sampling and elucidate the relationship between sensing depth of the Raman effect and optical properties of the tissue under interrogation. Approach: A new Monte Carlo (MC) package was developed to simulate absorption, fluorescence, elastic, and inelastic scattering of light in tissue. The validity of the MC algorithm was demonstrated by comparison with experimental Raman spectra in phantoms of known optical properties using nylon and polydimethylsiloxane as Raman-active compounds. A series of MC simulations were performed to study the effects of optical properties on Raman sensing depth for an imaging geometry consistent with single-point detection using a handheld fiber optics probe system. Results: The MC code was used to estimate the Raman sensing depth of a handheld fiber optics system. For absorption and reduced scattering coefficients of 0.001 and 1 mm − 1, the sensing depth varied from 105 to 225 μm for a range of Raman probabilities from 10 − 6 to 10 − 3. Further, for a realistic Raman probability of 10 − 6, the sensing depth ranged between 10 and 600 μm for the range of absorption coefficients 0.001 to 1.4 mm − 1 and reduced scattering coefficients of 0.5 to 30 mm − 1. Conclusions: A spectroscopic MC light transport simulation platform was developed and validated against experimental measurements in tissue phantoms and used to predict depth sensing in tissue. It is hoped that the current package and reported results provide the research community with an effective simulating tool to improve the development of clinical applications of RS.
- Published
- 2020
32. First demonstration of 30 eVee ionization energy resolution with Ricochet germanium cryogenic bolometers.
- Author
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Ricochet Collaboration, Augier, C., Baulieu, G., Belov, V., Bergé, L., Billard, J., Bres, G., Bret, J. -. L., Broniatowski, A., Calvo, M., Cazes, A., Chaize, D., Chala, M., Chapellier, M., Chaplinsky, L., Chemin, G., Chen, R., Colas, J., Cudmore, E., and De Jesus, M.
- Subjects
GERMANIUM detectors ,MODULATION-doped field-effect transistors ,BOLOMETERS ,NUCLEAR energy ,IONIZATION energy ,GERMANIUM ,ELASTIC scattering - Abstract
The future Ricochet experiment aims to search for new physics in the electroweak sector by measuring the Coherent Elastic Neutrino-Nucleus Scattering process from reactor antineutrinos with high precision down to the sub-100 eV nuclear recoil energy range. While the Ricochet collaboration is currently building the experimental setup at the reactor site, it is also finalizing the cryogenic detector arrays that will be integrated into the cryostat at the Institut Laue Langevin in early 2024. In this paper, we report on recent progress from the Ge cryogenic detector technology, called the CryoCube. More specifically, we present the first demonstration of a 30 eVee (electron equivalent) baseline ionization resolution (RMS) achieved with an early design of the detector assembly and its dedicated High Electron Mobility Transistor (HEMT) based front-end electronics with a total input capacitance of about 40 pF. This represents an order of magnitude improvement over the best ionization resolutions obtained on similar phonon-and-ionization germanium cryogenic detectors from the EDELWEISS and SuperCDMS dark matter experiments, and a factor of three improvement compared to the first fully-cryogenic HEMT-based preamplifier coupled to a CDMS-II germanium detector with a total input capacitance of 250 pF. Additionally, we discuss the implications of these results in the context of the future Ricochet experiment and its expected background mitigation performance. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Momentum work and the energetic foundations of physics. II. The ideal gas law derived via processes.
- Author
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Kalies, Grit, Do, Duong D., and Arnrich, Steffen
- Subjects
IDEAL gases ,MECHANICS (Physics) ,ZERO point energy ,ELASTIC scattering ,PHYSICS ,THERMODYNAMIC state variables ,CLASSICAL mechanics - Abstract
In Paper I of this series, the elastic collision was described via simultaneous processes, where the energy is conserved at any moment. In this paper, we critically review the kinetic theory of gases, which was developed based on Newtonian mechanics, and show that it violates the principle of the conservation of energy. By placing the energy conservation at the beginning of the deductive formalism, we derive the ideal gas law via equally strong simultaneous counter-processes at the walls, namely, momentum work and volume work. Several new insights into the state variables of an ideal gas are obtained: (i) pressure cannot be expressed via the kinetic energy of an ideal gas, and (ii) temperature can be interpreted as a particle-related (microscopic) state variable. The historical choice to set a zero point of the potential energy for a confined ideal gas needs to be corrected, and the internal energy of an ideal gas turns out to include more forms of energy than specified in the kinetic theory of gases. Finally, and importantly, we show that the process approach to an ideal gas and thus to collisions is experimentally confirmed. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. Numerical Studies of Coulomb Collisions, Relaxation, and Debye Shielding by N-Body Simulation.
- Author
-
Wang, Cheng-Pu and Nishimura, Yasutaro
- Subjects
ELASTIC scattering ,CHEMICAL relaxation ,ELECTRON distribution ,PLASMA kinetic theory ,ANISOTROPY - Abstract
Basic kinetic process of plasmas is studied by a first principle based N-body simulation. By confirming Coulomb collisional relaxation process, this paper is extended to investigate the dynamics of Debye shielding. Some of the key numerical techniques are discussed, including how to avoid singularities at the near encounter of two charged particles. Electron distribution function in Debye shielding is revealed, which deviates from conventional Maxwellian distribution function. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
35. Collaboration with Dr. Efrem Sh. Soukhovitsukii: our fortuitous experiences on optical model analysis, his contribution to nuclear data activities of Japan and a posthumous study on light-nuclei.
- Author
-
Kunieda, Satoshi, Iwamoto, Osamu, Fukahori, Tokio, and Chiba, Satoshi
- Subjects
NUCLEAR physics ,ABSORPTION cross sections ,ANGULAR distribution (Nuclear physics) ,ELASTIC scattering ,NUCLEAR structure ,NUCLEAR energy ,INELASTIC scattering - Abstract
Optical model or coupled-channels calculation serves as an entrance to sophisticated calculation of nuclear data. It gives the optical quantities such as total, shape elastic scattering, absorption cross sections, direct inelastic scattering cross sections, angular distributions of elastic and inelastic scattering, and transmission coefficients for subsequent statistical model calculations. Traditionally, coupling of the elastic scattering channel to excited states of the target nucleus was ignored or treated with a simplified model such as rigid rotor or harmonic oscillator. It was a great contribution of Dr. Efrem Sh. Soukhovitsukii who has developed an excellent computation scheme which takes account of the low-lying collective nuclear structure in terms of the soft-rotator + vibrational model, and integrated it into the coupled-channels calculation. This methodology was realized as 2 computer codes, SHEMMAN and OPTMAN. In Japan, we had a fortuitous experience with him to employ this methodology in nuclear data evaluation, which started as a nuclear physics work to analyze neutron-scattering cross section of 12 C which were published as a series of 3 papers in Nuclear Physics A journal. After recognizing the usefulness of this methodology, it was applied to evaluation of nuclear data gradually and extensively, which resulted in obtaining awards of Atomic Energy Society of Japan (AESJ) by one of the authors (SK). This paper describes our collaborative works and recent findings on light-nuclei based on what he had developed. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
36. A remark on the paper 'partial wave singularities near j = 1 and high energy elastic scattering'
- Author
-
L.Ya. Pomeranchuk, V.N. Gribov, and K.A. Ter-Martirosyan
- Subjects
Scattering amplitude ,Physics ,Elastic scattering ,Scattering ,Quantum mechanics ,Quantum electrodynamics ,Crossing ,General Physics and Astronomy ,Scattering length ,Optical theorem ,Scattering theory ,Inelastic scattering - Published
- 1964
37. Inelastic scattering and solvent scattering reduce dynamical diffraction in biological crystals
- Author
-
Jan Pieter Abrahams and Tatiana Latychevskaia
- Subjects
Diffraction ,Electrons ,Inelastic scattering ,010403 inorganic & nuclear chemistry ,01 natural sciences ,Molecular physics ,03 medical and health sciences ,Microscopy, Electron, Transmission ,protein crystallography ,Materials Chemistry ,030304 developmental biology ,Elastic scattering ,multislice calculation ,0303 health sciences ,Crystallography ,Scattering ,Electron crystallography ,Chemistry ,Cryoelectron Microscopy ,Metals and Alloys ,Proteins ,Research Papers ,Atomic and Molecular Physics, and Optics ,Elasticity ,inelastic electron scattering ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,electron crystallography ,Electron diffraction ,X-ray crystallography ,Solvents ,electron diffraction ,cryo-EM ,Protein crystallization ,Crystallization - Abstract
Multiple, dynamical electron diffraction can be simulated by multislice calculations. However, experimental evidence indicates that these calculations overestimate dynamical diffraction. It is shown that ignoring bulk solvent scattering and inelastic scattering in calculations, results in overestimating dynamical effects., Multi-slice simulations of electron diffraction by three-dimensional protein crystals have indicated that structure solution would be severely impeded by dynamical diffraction, especially when crystals are more than a few unit cells thick. In practice, however, dynamical diffraction turned out to be less of a problem than anticipated on the basis of these simulations. Here it is shown that two scattering phenomena, which are usually omitted from multi-slice simulations, reduce the dynamical effect: solvent scattering reduces the phase differences within the exit beam and inelastic scattering followed by elastic scattering results in diffusion of dynamical scattering out of Bragg peaks. Thus, these independent phenomena provide potential reasons for the apparent discrepancy between theory and practice in protein electron crystallography.
- Published
- 2019
38. Elastic propagation of fast electron vortices through amorphous materials
- Author
-
Thomas Schachinger, Stefan Sack, and Stefan Löffler
- Subjects
Angular momentum ,elastic scattering ,FOS: Physical sciences ,02 engineering and technology ,Electron ,amorphous materials ,01 natural sciences ,Biochemistry ,Inorganic Chemistry ,Structural Biology ,Condensed Matter::Superconductivity ,0103 physical sciences ,General Materials Science ,Cylindrical coordinate system ,Physical and Theoretical Chemistry ,electron vortex beams ,010302 applied physics ,Physics ,Elastic scattering ,Condensed Matter - Materials Science ,Quantum Physics ,Scattering ,Materials Science (cond-mat.mtrl-sci) ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Research Papers ,Computational physics ,Amorphous solid ,Vortex ,Cathode ray ,0210 nano-technology ,Quantum Physics (quant-ph) - Abstract
This article describes the scattering behavior of electron vortices inside amorphous samples. It focuses on the vortex purity, net angular momentum transfer, and statistical variations due to random beam and atom positions., This work studies the elastic scattering behavior of electron vortices when propagating through amorphous samples. A formulation of the multislice approach in cylindrical coordinates is used to theoretically investigate the redistribution of intensity between different angular momentum components due to scattering. To corroborate and elaborate on our theoretical results, extensive numerical simulations are performed on three model systems (Si3N4, Fe0.8B0.2, Pt) for a wide variety of experimental parameters to quantify the purity of the vortices, the net angular momentum transfer, and the variability of the results with respect to the random relative position between the electron beam and the scattering atoms. These results will help scientists to further improve the creation of electron vortices and enhance applications involving them.
- Published
- 2019
- Full Text
- View/download PDF
39. Drift Velocity with Elastic Scattering.
- Author
-
Morin, Rachel M. and Mecholsky, Nicholas A.
- Subjects
VELOCITY ,MONTE Carlo method ,QUANTUM mechanics ,STATISTICAL mechanics ,ELASTIC scattering ,CLASSICAL mechanics - Abstract
The drift velocity of a particle under a driving force has its roots in the theory of electrical conduction. Although it has been studied for over 100 years, it still yields surprises. At the heart of a particle's drift velocity is an interplay of classical, quantum, and statistical mechanics. Irreversibility and energy loss have been assumed as essential features of drift velocities and very little effort has been made to isolate the aspects of particle transport that are due to elastic mechanisms alone. In this paper, we remove energy loss and quantum mechanics to investigate the classical and statistical factors that can produce a drift velocity using only elastic scattering. A Monte Carlo simulation is used to model a particle in a uniform force field, subject to randomly placed scatterers. Time-, space-, and energy-dependent scattering models, with varied ranges of scattering angles, are investigated. A constant drift velocity is achieved with the time scattering model, which has a constant average time between scattering events. A decreasing drift velocity is observed for space and energy-dependent models. The arrival of a constant drift velocity has to do with a balance of momentum gained between collisions and momentum lost after a collision. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
40. Billiard in a rotating half-plane.
- Author
-
Kryzhevich, Sergey and Plakhov, Alexander
- Subjects
BILLIARDS ,ELASTIC scattering ,CONTINUOUS time models ,SYSTEM dynamics - Abstract
The main objective of this research is to study the properties of a billiard system in an unbounded domain with moving boundary. We consider a system consisting of an infinite rod (a straight line) and a ball (a massless point) on the plane. The rod rotates uniformly around one of its points and experiences elastic collisions with the ball. We define a mathematical model for the dynamics of such a system and write down asymptotic formulae for its motions. In particular, we determine existence and uniqueness of solutions. We find all possible grazing impacts of the ball. Besides, we demonstrate that for almost every initial condition, the ball goes to infinity exponentially fast, with the time intervals between neighboring collisions tending to zero. The approach developed in this paper is an original combination of methods of Billiards and Vibro-Impact Dynamics. It could be a base for studying more complicated systems of similar types. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
41. Simultaneous events, singularity in the space of models and chicken game.
- Author
-
Raczynski, Stanislaw
- Subjects
DISCRETE event simulation ,ELASTIC scattering ,CHICKENS - Abstract
The discrete event simulation with simultaneous events is discussed. Discrete models are treated as some points in the general space of models. The main topic of this paper is the convergence of sequences of continuous models to the corresponding discrete event model. It is pointed out that the discrete event models may represent some singularities in the space of models. This fact is related to the problem of validity of discrete event simulation. The models presented here are not the topic of the paper. These are known models, used as examples. The model of the "chicken game" and multiple elastic collisions are considered. It is shown that if a discrete event model is some special limit case of a sequence of continuous models with finite event duration, then that limit model is a singularity. It may provide results very different from the expected limit value of the results from the converging sequence of models. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
42. Molecular Dynamics Simulations of Primary Radiation Damage in Silicon Carbide.
- Author
-
KUCAL, E., CZERSKI, K., and KOZIOŁ, Z.
- Subjects
MOLECULAR dynamics ,RADIATION damage ,CRYSTAL defects ,ELASTIC scattering ,ATOMIC displacements ,SILICON carbide ,NEUTRON irradiation - Abstract
Molecular dynamics simulations provide information on atomic displacement cascades due to the ionic collisions on the time scale of picoseconds and simultaneously account for the effects of crystal structure and temperature. Thus, molecular dynamics can help to understand the specific material behaviour during ion irradiation and make predictions for long-term neutron exposure as well. The latter is especially important for new generations of high-temperature reactors which use ceramics as construction materials. The paper presents the preliminary molecular dynamics simulations of argon irradiation of the SiC sample at very low energies, where mainly elastic collisions dominate, and two different sample temperatures are presented. The obtained results clearly illustrate the time-dependent reduction of the crystal defect number and the influence of the electronic stopping power. Additionally, the number of sustainable crystal defects depends largely on the sample temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
43. Complex translation methods and its application to resonances for quantum walks.
- Author
-
Higuchi, Kenta and Morioka, Hisashi
- Subjects
- *
RESONANCE , *ELASTIC scattering , *QUANTUM scattering , *MOMENTUM space , *PSEUDODIFFERENTIAL operators , *CLASSICAL mechanics , *ROTATIONAL motion - Abstract
In this paper, some properties of resonances for multi-dimensional quantum walks are studied. Resonances for quantum walks are defined as eigenvalues of complex translated time evolution operators in the pseudo momentum space. For some typical cases, we show some results of existence or nonexistence of resonances. One is a perturbation of an elastic scattering of a quantum walk which is an analogue of classical mechanics. Another one is a shape resonance model which is a perturbation of a quantum walk with a non-penetrable barrier. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Absolute cross section measurements for the scattering of low- and intermediate-energy electrons from PF3. I. Elastic scattering.
- Author
-
Hishiyama, N., Hoshino, M., Blanco, F., García, G., and Tanaka, H.
- Subjects
ELASTIC scattering ,INTERMEDIATES (Chemistry) ,CROSS-sectional method ,COLLISIONS (Nuclear physics) ,PHOSPHORUS fluorides ,MOMENTUM transfer - Abstract
We report absolute elastic differential cross sections (DCSs) for electron collisions with phosphorus trifluoride, PF
3 , molecules (e- + PF3 ) in the impact energy range of 2.0-200 eV and over a scattering angle range of 10°-150°. Measured angular distributions of scattered electron intensities were normalized by reference to the elastic DCSs of He. Corresponding integral and momentum-transfer cross sections were derived by extrapolating the angular range from 0° to 180° with the help of a modified phase-shift analysis. In addition, due to the large dipole moment of the considered molecule, the dipole-Born correction for the forward scattering angles has also been applied. As a part of this study, independent atom model calculations in combination with screening corrected additivity rule were also performed for elastic and inelastic (electronic excitation plus ionization) scattering using a complex optical potential method. Rotational excitation cross sections have been estimated with a dipole-Born approximation procedure. Vibrational excitations are not considered in this calculation. Theoretical data, at the differential and integral levels, were found to reasonably agree with the present experimental results. Furthermore, we explore the systematics of the elastic DCSs for the four-atomic trifluoride molecules of XF3 (X = B, N, and P) and central P-atom in PF3 , showing that, owing to the comparatively small effect of the F-atoms, the present angular distributions of elastic DCSs are essentially dominated by the characteristic of the central P-atom at lower impact energies. Finally, these quantitative results for e- - PF3 collisions were compiled together with the previous data available in the literature in order to obtain a cross section dataset for modeling purposes. To comprehensively describe such a considerable amount of data, we proceed by first discussing, in this paper, the vibrationally elastic scattering processes whereas vibrational and electronic excitation shall be the subject of our following paper devoted to inelastic collisions. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
45. Direct heavy ion transfer reactions
- Author
-
Phillips, W. R., Ehlers, J., editor, Hepp, K., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Zittartz, J., editor, Beiglböck, W., editor, and Robson, B. A., editor
- Published
- 1976
- Full Text
- View/download PDF
46. An efficient big data classification using elastic collision seeker optimization based faster R-CNN.
- Author
-
Chidambaram, S., Cyril, C. Pretty Diana, and Ganesh, S. Sankar
- Subjects
ELASTIC scattering ,BIG data ,MACHINE learning ,CLASSIFICATION - Abstract
Big data is a large set of data that is analyzed with the calculation to manifest myriad sources. Big data is capable of handling various challenges to processing huge amounts of data. To handle issues based on large-scale databases, a MapReduce framework is employed which provides robust and simple infrastructure for huge datasets. This paper proposes a novel Elastic collision seeker optimization based Faster R-CNN (ECSO-FRCNN) classifier for efficient big data classification. The proposed ECSO-FRCNN classifier is capable of handling missing attributes, and incremental learning and improves training performance effectively. As the proposed technique deals with large data samples, it necessitates the inclusion of the MapReduce framework. The adaption of MapReduce design in big data classification prevents the classification results from uncertainties such as data redundancy, misclassification, and storage issues. The proposed method is examined with three standard datasets, namely the skin segmentation dataset, mushroom dataset, and localization dataset, collected from the University of California, UCI machine learning repository. Finally, extensive experimental analysis is carried out for various parameters to depict the efficiency of the system. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
47. Electronic Structure, Spectroscopy, Cold Ion–Atom Elastic Collision Properties, and Photoassociation Formation Prediction of the (MgCs) + Molecular Ion.
- Author
-
Farjallah, Mohamed, Sardar, Dibyendu, Deb, Bimalendu, and Berriche, Hamid
- Subjects
ION-atom collisions ,IONS ,ELASTICITY ,ELECTRONIC structure ,ELASTIC scattering ,POTENTIAL energy - Abstract
In this paper, we extensively study the electronic structure, interactions, and dynamics of the (MgCs)
+ molecular ion. The exchanges between the alkaline atom and the low-energy cationic alkaline earths, which are important in the field of cold and ultracold quantum chemistry, are studied. We use an ab initio approach based on the formalism of non-empirical pseudo-potential for Mg2+ and Cs+ cores, large Gaussian basis sets, and full-valence configuration interaction. In this context, the (MgCs)+ cation is treated as an effective two-electron system. Adiabatic potential energy curves and their spectroscopic constants for the ground and the first 20 excited states of1,3 Σ+ symmetries are determined. Furthermore, we identify the avoided crossings between the electronic states of1,3 Σ+ symmetries. These crossings are related to the charge transfer process between the two ionic limits, Mg/Cs+ and Mg+ /Cs. Therefore, vibrational-level spacings and the transition and permanent dipole moments are presented and analyzed. Using the produced potential energy data, the ground-state scattering wave functions and elastic cross-sections are calculated for a wide range of energies. In addition, we predict the formation of a translationally and rotationally cold molecular ion (MgCs)+ in the ground-state electronic potential energy through a stimulated Raman-type process aided by ion–atom cold collision. In the low-energy limit (<1 mK), elastic scattering cross-sections exhibit Wigner law threshold behavior, while in the high-energy limit, the cross-sections act as a function of energy E go as E−1/3 . A qualitative discussion about the possibilities of forming cold (MgCs)+ molecular ions by photoassociative spectroscopy is presented. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
48. A comparison of experimental and theoretical low energy positron scattering from furan.
- Author
-
Cheong, Z., Moreira, G. M., Bettega, M. H. F., Blanco, F., Garcia, G., Brunger, M. J., White, R. D., and Sullivan, J. P.
- Subjects
ELASTIC scattering ,ELECTRON scattering ,INELASTIC scattering ,POSITRONS ,POSITRONIUM - Abstract
This paper presents a joint experimental and theoretical study of positron scattering from furan. Experimental data were measured using the low energy positron beamline located at the Australian National University and cover an energy range from 1 eV to 30 eV. Cross sections were measured for total scattering, total elastic and inelastic scattering, positronium formation, and differential elastic scattering. Two theoretical approaches are presented: the Schwinger multichannel method and the independent atom method with screening corrected additivity rule. In addition, our data are compared to corresponding electron scattering results from the same target with a number of significant differences observed and discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
49. Angularly resolved, finely sampled elastic scattering measurements of single cells: requirements for robust organelle size extractions
- Author
-
Janet E. Sorrells, Ashley E. Cannaday, and Andrew J. Berger
- Subjects
Paper ,Light ,angular scattering ,Mie scattering ,Biomedical Engineering ,Signal-To-Noise Ratio ,Models, Biological ,01 natural sciences ,Noise (electronics) ,Instability ,Light scattering ,elastic light scattering ,010309 optics ,Biomaterials ,Mice ,Cell Line, Tumor ,0103 physical sciences ,Calibration ,Mie theory ,Animals ,Scattering, Radiation ,Computer Simulation ,Particle Size ,Organelles ,Elastic scattering ,Physics ,Microscopy ,Fourier Analysis ,Scattering ,Reproducibility of Results ,Ray ,Elasticity ,Atomic and Molecular Physics, and Optics ,single cell ,Mitochondria ,Electronic, Optical and Magnetic Materials ,Computational physics ,Organelle Size ,Carcinoma, Squamous Cell ,Polystyrenes - Abstract
Angularly resolved elastic light scattering is an established technique for probing the average size of organelles in biological tissue and cellular ensembles. Focusing of the incident light to illuminate no more than one cell at a time restricts the minimum forward-scattering angle θmin that can be detected. Series of simulated single-cell angular-scattering patterns have been generated to explore how size estimates vary as a function of θmin. At a setting of θmin=20 deg, the size estimates hop unstably between multiple minima in the solution space as simulated noise (mimicking experimentally observed levels) is varied. As θmin is reduced from 20 deg to 10 deg, the instability vanishes, and the variance of estimates near the correct answer also decreases. The simulations thus suggest that robust Mie theory fits to single-cell scattering at 785 nm excitation require measurements down to at least 15 deg. Notably, no such instability was observed at θmin=20 deg for narrow bead distributions. Accurate sizing of traditional calibration beads is, therefore, insufficient proof that an angular-scattering system is capable of robust analysis of single cells. Experimental support for the simulation results is also presented using measurements on cells fixed with formaldehyde.
- Published
- 2019
50. Shannon entropy of resonant scattered state in the eâ€"C60 elastic collision.
- Author
-
Sarswat, Shruti, R, Aiswarya, and Jose, Jobin
- Subjects
RESONANT states ,ELASTIC scattering ,ENTROPY ,RESONANCE - Abstract
Resonance is a remarkable feature in elastic scattering and the resonant states of eâ€"C
60 scattering are benchmarked using Shannon entropy in the present work. The resonant wavefunction, total cross-section, partial cross-sections, and scattering phase shifts are calculated for the eâ€"C60 scattering to review the localization properties owing to resonance. Three different model interaction potentials are used in the paper to simulate the environment of the C60 shell; annular square well, Gaussian annular square well, and Lorentzian potential. This paper aims to establish a relationship between the Shannon entropy and resonant properties linked with e + C60 scattering. This work introduces the Shannon entropy as an indicator of resonance in elastic scattering and it unveils the susceptibility of entropic properties to the nature of the model potential. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
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