Journal articles: 'Distribution energie initiale'

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SZCZUREK, ANTONI. "DIFFRACTIVE DOUBLE-ELASTIC PRODUCTION OF η′ AND ηc IN THE pp → pXp REACTION." International Journal of Modern Physics A 22, no. 02n03 (January 30, 2007): 667–71. http://dx.doi.org/10.1142/s0217751x07036087.

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I discuss double-diffractive (double-elastic) production of the η′ and ηc mesons in the pp → pXp reaction within the formalism of unintegrated gluon distribution functions (UGDF). The contribution of γ*γ* → η′ fusion is estimated. The distributions in the Feynman xF (or rapidity), transferred four-momenta squared between initial and final protons (t1, t2) and azimuthal angle difference between outgoing protons (Φ) are calculated and discussed. The results are compared with the WA102 data. Predictions at higher energies are presented.

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DURÃES, F. O., F. S. NAVARRA, and M. NIELSEN. "J/ψ RAPIDITY DISTRIBUTIONS IN THE SATURATION REGIME." International Journal of Modern Physics E 16, no. 07n08 (August 2007): 2079–84. http://dx.doi.org/10.1142/s0218301307007490.

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In this work we calculate the J/ψ production in the initial stage of hadronic and nuclear collisions at RHIC and LHC energies, taking into account the high parton density regime of Quantum Chromodynamics (QCD), where the physics of parton saturation is expected to be dominant. We perform a quantitative analysis of the rapidity distributions in these collisions with the Color Glass Condensate (CGC) approach. The ratio between distributions with or without saturated gluons shows that this mechanism produces a suppression of the J/ψ yield in the forward region only at very high energies.

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Soldin, Dennis. "Atmospheric Muons Measured with IceCube." EPJ Web of Conferences 208 (2019): 08007. http://dx.doi.org/10.1051/epjconf/201920808007.

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IceCube is a cubic-kilometer Cherenkov detector in the deep ice at the geographic South Pole. The dominant event yield is produced by penetrating atmospheric muons with energies above several 100 GeV. Due to its large detector volume, IceCube provides unique opportunities to study atmospheric muons with large statistics in detail. Measurements of the energy spectrum and the lateral separation distribution of muons offer insights into hadronic interactions during the air shower development and can be used to test hadronic models. We will present an overview of various measurements of atmospheric muons in IceCube, including the energy spectrum of muons between 10 TeV and 1 PeV. This is used to derive an estimate of the prompt contribution of muons, originating from the decay of heavy (mainly charmed) hadrons and unflavored mesons. We will also present measurements of the lateral separation distributions of TeV muons between 150m and 450m for several initial cosmic ray energies between 1 PeV and 16 PeV. Finally, the angular distribution of atmospheric muons in IceCube will be discussed.

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Mezei, Zsolt J., Michel D. Epée Epée, Ousmanou Motapon, and Ioan F. Schneider. "Dissociative Recombination of CH+ Molecular Ion Induced by Very Low Energy Electrons." Atoms 7, no. 3 (August 19, 2019): 82. http://dx.doi.org/10.3390/atoms7030082.

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We used the multichannel quantum defect theory to compute cross sections and rate coefficients for the dissociative recombination of CH + initially in its lowest vibrational level v i + = 0 with electrons of incident energy below 0.2 eV. We have focused on the contribution of the 2 2 Π state which is the main dissociative recombination route at low collision energies. The final cross section is obtained by averaging the relevant initial rotational states ( N i + = 0 , ⋯ , 10 ) with a 300 K Boltzmann distribution. The Maxwell isotropic rate coefficients for dissociative recombination are also calculated for different initial rotational states and for electronic temperatures up to a few hundred Kelvins. Our results are compared to storage-ring measurements.

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PIETRYCKI, TOMASZ, and ANTONI SZCZUREK. "DIRECT PHOTON PRODUCTION IN pp AND $p {\bar p}$ COLLISIONS AT HIGH ENERGIES." International Journal of Modern Physics A 22, no. 02n03 (January 30, 2007): 541–45. http://dx.doi.org/10.1142/s0217751x07035793.

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The invariant cross sections for direct photon production in hadron-hadron collisions are calculated for several initial energies (SPS, ISR, [Formula: see text], RHIC, Tevatron, LHC) including initial parton transverse momenta within the formalism of unintegrated parton distributions (UPDF). Kwieciński UPDFs provide very good description of all world data, especially at SPS and ISR energies. Inclusion of the QCD evolution effects and especially their effect on initial parton transverse momenta allowed to solve the long-standing problem of understanding the low energy and low transverse momentum data.

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Riahi, Rashid, and Morteza Raeisi. "Classical and semiclassical description of initial distributions of kaon capture by atomic hydrogen and deuterium." Canadian Journal of Physics 91, no. 3 (March 2013): 273–78. http://dx.doi.org/10.1139/cjp-2012-0481.

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The moderation and capture of negative kaons by atomic hydrogen and deuterium were investigated by the classical trajectory Monte–Carlo (CTMC) and the semiclassical fermion molecular dynamics (FMD) methods. The dependence of ionization and capture cross sections on initial kaon energy was also studied. The initial populations of kaonic atom levels were calculated. The n distributions of kaonic atoms peaked close to the orbital giving optimum overlap with the displaced electronic orbital. The angular momentum distributions, l, are found to be approximately statistical but cut off at large l smaller than lmax = n − 1 in large n. The results are compared with the adiabatic ionization, diabatic states, and Born approximation methods. The FMD results were found to be in better agreement with quantum mechanical calculations than the ones from CTMC. The kaon kinetic energy spectrum prior to capture was calculated, which reveals that capture occurs at small collision energies up to the ionization energy. Also, the calculations show that kaonic hydrogen (deuterium) atoms have kinetic energies below 0.3 a.u. (0.15 a.u.) after formation.

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Pino, G. A., C. A. Rinaldi, E. A. Coronado, and J. C. Ferrero. "Collisional relaxation of highly vibrationally excited CF2O prepared with different initial energies and distribution functions." Journal of Chemical Physics 110, no. 4 (January 22, 1999): 1942–48. http://dx.doi.org/10.1063/1.477861.

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8

Konishi, Eiji. "Core-halo quasi-stationary states in the Hamiltonian mean-field model." International Journal of Modern Physics B 30, no. 12 (May 6, 2016): 1630007. http://dx.doi.org/10.1142/s0217979216300073.

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A characteristic feature of long-range interacting systems is that they become trapped in a non-equilibrium and long-lived quasi-stationary state (QSS) during the early stages of their development. We present a comprehensive review of recent studies of the core-halo structure of QSSs, in the Hamiltonian mean-field model (HMF), which is a mean-field model of mutually coupled ferromagnetic XY spins located at a point, obtained by starting from various unsteady rectangular water-bag type initial phase-space distributions. The main result exposed in this review is that the core-halo structure can be described by the superposition of two independent Lynden–Bell distributions. We discuss the completeness of collisionless relaxation of this double Lynden–Bell distribution by using both of Lynden–Bell entropy and double Lynden–Bell entropy for the systems at low energies per particle.

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Berinskii, I., and V. A. Kuzkin. "Equilibration of energies in a two-dimensional harmonic graphene lattice." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, no. 2162 (November 25, 2019): 20190114. http://dx.doi.org/10.1098/rsta.2019.0114.

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We study dynamical phenomena in a harmonic graphene (honeycomb) lattice, consisting of equal particles connected by linear and angular springs. Equations of in-plane motion for the lattice are derived. Initial conditions typical for molecular dynamic modelling are considered. Particles have random initial velocities and zero displacements. In this case, the lattice is far from thermal equilibrium. In particular, initial kinetic and potential energies are not equal. Moreover, initial kinetic energies (and temperatures), corresponding to degrees of freedom of the unit cell, are generally different. The motion of particles leads to equilibration of kinetic and potential energies and redistribution of kinetic energy among degrees of freedom. During equilibration, the kinetic energy performs decaying high-frequency oscillations. We show that these oscillations are accurately described by an integral depending on dispersion relation and polarization matrix of the lattice. At large times, kinetic and potential energies tend to equal values. Kinetic energy is partially redistributed among degrees of freedom of the unit cell. Equilibrium distribution of the kinetic energies is accurately predicted by the non-equipartition theorem. Presented results may serve for better understanding of the approach to thermal equilibrium in graphene. This article is part of the theme issue ‘Modelling of dynamic phenomena and localization in structured media (part 2)’.

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SARCEVIC, INA. "KNO SCALING IN THE PARTON BRANCHING MODEL." Modern Physics Letters A 02, no. 07 (July 1987): 513–23. http://dx.doi.org/10.1142/s021773238700063x.

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We obtain a parton branching distribution Pmn of m quarks and n gluons. We show that this distribution does not obey exact KNO scaling. In the case when quark evolution is neglected, the probability distribution becomes wider as energy increases, in agreement with experimental data. We find that moments fit the data remarkably well with an increasing initial number of gluons and decreasing initial number of quarks. In this model, we predict the upper bounds for the probability distribution and multiplicity moments. We also give theoretical predictions for the multiplicities and moments for Tevatron Collider energies, indicating the slow narrowing of the probability distribution in this energy range.

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11

Tang, Hong. "Retrieval of spherical particle size distribution with an improved Tikhonov iteration method." Thermal Science 16, no. 5 (2012): 1400–1404. http://dx.doi.org/10.2298/tsci1205400t.

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The problem of retrieval for spherical particle size distribution in the independent mode is studied, and an improved Tikhonov iteration method is proposed. In this method, the particle size distribution is retrieved from the light extinction data through the Phillips-Twomey method firstly in the independent mode, and then the obtained inversion results of the particle size distribution is used as the initial distribution and the final retrieved particle size distribution is obtained. Simulation experiments indicate that the spherical particle size distributions obtained with the proposed method coincide fairly well with the given distributions.

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MA, LI, JIANGUANG WANG, and GUANGHOU WANG. "INITIAL PROCESSES OF HYDROGEN CHEMISORPTION ON Si(111) SURFACE." International Journal of Modern Physics B 20, no. 28 (November 10, 2006): 4799–805. http://dx.doi.org/10.1142/s0217979206035722.

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The chemisorption of one monolayer H atoms on Si (111) surface is studied by using the self-consistent, tight-binding, linear muffin-tin orbital method. Energies of adsorption systems, the layer projected density of states (LPDOS) and charge distributions are calculated. It is found that the adsorbed H atoms are more favorable on the top site with a distance of 0.185 nm above the Si surface. The LPDOS in the clean surface decreases significantly after H adsorption, since the dangling bonds of the surface atoms are partially saturated by the adsorbed H atoms.

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Melkikh, A. V., E. A. Melkikh, and V. A. Kozhevnikov. "Numerical Modeling of Material Points Evolution in a System with Gravity." Communications in Computational Physics 21, no. 4 (March 8, 2017): 1118–40. http://dx.doi.org/10.4208/cicp.oa-2015-0004.

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AbstractThe evolution of material points interacting via gravitational force in 3D space was investigated. At initial moment points with masses of 2.48 Sun masses are randomly distributed inside a cube with an edge of 5 light-years. The modeling was conducted at different initial distributions of velocities and different ratios between potential and kinetic energy of the points. As a result of modeling the time dependence of velocity distribution function of points was obtained. Dependence of particles fraction which had evaporated frominitial cluster on time for different initial conditions is obtained. In particular, it was obtained that the fraction of evaporated particles varies between 0,45 and 0,63.Mutual diffusion of two classes of particles at different initial conditions in the case when at initial moment of time both classes of particles occupy equal parts of cube was investigated.The maximum Lyapunov exponent of the system with different initial conditions was calculated. The obtained value weakly depends on the ratio between initial kinetic and potential energies and amounts approximately 10–5. Corresponding time of the particle trajectories divergence turned out to be 40-50 thousand years.

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Krauss-Varban, Dietmar, and Brian T. Welsch. "Solar flare particle heating via low-β reconnection." Proceedings of the International Astronomical Union 2, no. 14 (August 2006): 89. http://dx.doi.org/10.1017/s1743921307009921.

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AbstractObservations give tight constraints on the temporal and spatial scales of particle heating in solar flares, and on the required efficiency. Electrons are accelerated into a quasi-thermal population of a few tens of keV. X- and γ-rays imply tails in electron and ion distributions reaching tens of MeV and above. Simple estimates indicate that all available electrons are accelerated at least once to moderate energies, pointing to an initial process resembling bulk heating rather than acceleration of a small or localized population. In the absence of effective collisions, wave-particle interactions are the prime candidate. Here we address the outstanding questions, (i) what process can heat the entire reconnecting plasma to the above energies, and (ii) what provides the free energy for wave-particle interactions? We propose a process in which initially the ions are heated and provide the free energy for electron heating and tail formation.

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15

Deutchman, P. A. "Identical nuclei in coherent pion production at intermediate energies." Canadian Journal of Physics 80, no. 9 (September 1, 2002): 941–50. http://dx.doi.org/10.1139/p02-032.

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The formalism for the calculation of constructive, coherent production of pions through the collision of intermediate-energy nuclei now includes for the first time the exchange symmetry due to identical nuclei both in the initial two-body state and in the final three-body state. Of the eight terms that contribute to the pion-energy distributions, four of the amplitudes are equal in pairs, effectively leaving four amplitudes with direct terms in the initial state and direct and exchange terms in the final state. Of these remaining amplitudes, the final-state exchange terms are negligible as far as the calculation is concerned. This holds for pion-energy distributions over the incident energies from 100 MeV/nucleon to 2 GeV/nucleon for pions fixed in the forward direction (θπ = 0°) and the projectile and target, respectively, fixed in the fore and aft directions. This work is also generalized to include schematic solutions for the cases of identical nuclei in the initial state only, identical nuclei in the final state only, and the case of no identical nuclei at all. PACS Nos.: 24.10Cn, 24.30Cz, 25.70-z, 25.80-e

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BLANN, MARSHALL. "JURASSIC (TRI) QUARK: AN ANGULAR DISTRIBUTION MODEL FOR HEAVY ION REACTIONS." International Journal of Modern Physics E 16, no. 04 (May 2007): 1065–71. http://dx.doi.org/10.1142/s0218301307006514.

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Double differential neutron emission spectra are calculated assuming initial directions and energies result from random angle coupling of beam energy and projectile Fermi momenta. Results are compared with data of Holub et al. for 300 MeV 12C+165Ho.The energy distributions resulting from the random angle assumption are compared with results of the exciton formula for A - 1 degrees of freedom, where A is the projectile mass number.

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17

Gürgöze, M. "On the Distribution of Energy between the Vibration Modes." International Journal of Mechanical Engineering Education 22, no. 2 (April 1994): 127–37. http://dx.doi.org/10.1177/030641909402200210.

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The initial energy of a conservative mechanical system is distributed between its vibratory modes. It is a known fact that if the system is displaced according to a certain mode shape and released with zero velocity then it vibrates only in that mode. In this study it is investigated whether it is possible, through appropriate selection of initial conditions, for energies in different modes to take prescribed ratios of the total energy. Keeping in mind the difficulties of many students with regard to modal quantities, a systematic treatment of the energy distribution between the modes is given. In doing so, the known results in the literature are pointed out as special cases. At the end of the paper two examples are given.

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CHATURVEDI, S., V. GUPTA, and S. K. SONI. "A UNIFIED VIEW OF MULTIPLICITY DISTRIBUTIONS BASED ON A PURE BIRTH PROCESS." Modern Physics Letters A 09, no. 36 (November 30, 1994): 3359–66. http://dx.doi.org/10.1142/s021773239400318x.

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Various probability distributions which have been proposed to explain the charged particle multiplicity distributions in high energy collisions are shown to arise from the evolution equation of a pure birth process subject to appropriate initial conditions. For example, both the negative binomial distribution (NBD) as well as the partially coherent laser distribution (PCLD) can be obtained in this way. New interrelations between some of these probability distributions are also brought out.

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Khokhlov, S. S., A. G. Bogdanov, V. A. Khomyakov, V. V. Kindin, R. P. Kokoulin, A. A. Petrukhin, V. V. Shutenko, and I. I. Yashin. "Energy spectrum of cascade showers initiated by cosmic ray muons in the Cherenkov water detector." EPJ Web of Conferences 208 (2019): 08018. http://dx.doi.org/10.1051/epjconf/201920808018.

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Results of analysis of experimental data on cascade showers with energies of 0.1 – 10 TeV initiated by muons in the Cherenkov water detector NEVOD are presented. The method of selection and reconstruction of cascade parameters in the volume of the detector is discussed. Experimental distributions of cascade axes in zenith angle and energy spectrum of cascades are obtained. The measured distributions are compared with results of calculations.

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KHANDAI, P. K., P. SETT, P. SHUKLA, and V. SINGH. "HADRON SPECTRA IN p+p COLLISIONS AT RHIC AND LHC ENERGIES." International Journal of Modern Physics A 28, no. 16 (June 28, 2013): 1350066. http://dx.doi.org/10.1142/s0217751x13500668.

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We present the systematic analysis of transverse momentum (pT) spectra of identified hadrons in p+p collisions at Relativistic Heavy Ion Collider ([Formula: see text] and 200 GeV) and at Large Hadron Collider (LHC) energies ([Formula: see text], 2.76 and 7.0 TeV) using phenomenological fit functions. We review various forms of Hagedorn and Tsallis distributions and show their equivalence. We use Tsallis distribution which successfully describes the spectra in p+p collisions using two parameters, Tsallis temperature T which governs the soft bulk spectra and power n which determines the initial production in partonic collisions. We obtain these parameters for pions, kaons and protons as a function of center-of-mass energy [Formula: see text]. It is found that the parameter T has a weak but decreasing trend with increasing [Formula: see text]. The parameter n decreases with increasing [Formula: see text] which shows that production of hadrons at higher energies are increasingly dominated by point like qq scatterings. Another important observation is with increasing [Formula: see text], the separation between the powers for protons and pions narrows down hinting that the baryons and mesons are governed by same production process as one moves to the highest LHC energy.

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21

Subramanian, V., and R. Baskaran. "Initial Size Distribution of Sodium Combustion Aerosol." Nuclear Technology 160, no. 3 (December 2007): 308–13. http://dx.doi.org/10.13182/nt07-a3901.

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22

Brown, KL, and J. Fletcher. "Electronic Energy Distribution Function at High Electron Swarm Energies in Neon." Australian Journal of Physics 48, no. 3 (1995): 479. http://dx.doi.org/10.1071/ph950479.

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Electron swarms moving through a gas under the influence of an applied electric field have been extensively investigated. Swarms at high energies, as measured by the ratio of the applieq field to the gas number density, E/N, which are predominant in many applications have, in general, been neglected. Discharges at E/N in the range 300 < E/N < 2500 Td have been investigated in neon gas in the pressure range 6 < po < 133 Pa using a differentially pumped vacuum system in which the swarm electrons are extracted from the discharge and energy analysed in both a parallel plate retarded potential analyser and a cylindrical electrostatic analyser. Both pre-breakdown and post-breakdown discharges have been studied. Initial results indicate that as the discharge traverses breakdown no sudden change in the nature of the discharge occurs and that the discharge can be described by both a Monte Carlo simulation and by a Boltzmann treatment given by Phelps et al. (1987).

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OKOROKOV, V. A. "DEPENDENCE OF ASYMMETRIES FOR CHARGE DISTRIBUTION WITH RESPECT TO THE REACTION PLANE ON INITIAL ENERGY IN HEAVY-ION COLLISIONS." International Journal of Modern Physics E 22, no. 06 (June 2013): 1350041. http://dx.doi.org/10.1142/s0218301313500419.

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In this paper, two combinations of correlators are defined in order to investigate the evolution of possible [Formula: see text] invariance violation in strong interactions with initial energy for heavy-ion collisions. These combinations correspond to absolute and relative asymmetry of distribution of electrically charge particles with respect to the reaction plane in heavy-ion collisions. Energy dependence of parameters under study was derived from data of STAR and ALICE experiments. Significant decreasing both absolute and relative asymmetry is observed at energies [Formula: see text]. This feature agrees qualitatively with other results of stage-I beam energy scan program in STAR experiment. General behavior of dependence of absolute asymmetry on initial energy agrees reasonably with behavior of similar dependence of Chern–Simons diffusion rate calculated at different values of external Abelian magnetic field. The observed behavior of parameters under study versus energy can be considered as indication on possible transition to predominance of hadronic states over quark–gluon degrees of freedom in the mixed phase created in heavy-ion collisions at intermediate energies.

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Kasza, Gábor, and Tamás Csörgő. "Lifetime estimations from RHIC Au+Au data." International Journal of Modern Physics A 34, no. 26 (September 20, 2019): 1950147. http://dx.doi.org/10.1142/s0217751x19501471.

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We discuss a recently found family of exact and analytic, finite and accelerating, [Formula: see text]-dimensional solutions of perfect fluid relativistic hydrodynamics to describe the pseudorapidity densities and longitudinal HBT-radii and to estimate the lifetime parameter and the initial energy density of the expanding fireball in Au[Formula: see text]+[Formula: see text]Au collisions at RHIC with [Formula: see text] GeV and 200 GeV colliding energies. From these exact solutions of relativistic hydrodynamics, we derive a simple and powerful formula to describe the pseudorapidity density distributions in high-energy proton–proton and heavy-ion collisions, and derive the scaling of the longitudinal HBT radius parameter as a function of the pseudorapidity density. We improve upon several oversimplifications in Bjorken’s famous initial energy density estimate, and apply our results to estimate the initial energy densities of high-energy reactions with data-driven pseudorapidity distributions. When compared to similar estimates at the LHC energies, our results indicate a surprising and nonmonotonic dependence of the initial energy density on the energy of heavy-ion collisions.

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Kalashnik, Maxim V., and Otto Chkhetiani. "An Analytical Approach to the Determination of Optimal Perturbations in the Eady Model." Journal of the Atmospheric Sciences 75, no. 8 (July 25, 2018): 2741–61. http://dx.doi.org/10.1175/jas-d-18-0089.1.

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Abstract Within the framework of the baroclinic instability Eady model, an analytical approach to the determination of optimal perturbations with a maximum of the energy growth rate or the ratio of the final and initial energies is considered. This approach is based on the energy balance equation and explicit expressions for the energy functionals resulting from the perturbation representation by means of the superposition of the edge Rossby waves (ERWs). The corresponding expressions are functions of the parameters of the initial perturbation, and the determination of optimal parameters reduces to the study of these functions on an extremum. For perturbations with zero potential vorticity (PV), the amplitudes of the initial buoyancy distributions at the boundaries of the atmospheric layer and the phase shift between these distributions serve as parameters. Analytical formulas are obtained for the optimal phase shift and the maximum of the energy ratio, which determine their dependence on the wavenumber and optimization time. It is also shown that the optimal perturbations always have equal boundary amplitudes. The parameters of the optimal perturbations are compared with the parameters of the growing normal modes. It is established that there exists only one exponentially growing normal mode, which is the optimal perturbation. Along with the instability, the ERWs can be excited by their interaction with the initial vortex perturbations (PV ≠ 0). The optimal regime of ERWs excitation by the initial singular distribution of PV is investigated.

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Yang, X. M., C. F. Drury, W. D. Reynolds, and D. C. MacTavish. "Use of sonication to determine the size distributions of soil particles and organic matter." Canadian Journal of Soil Science 89, no. 4 (August 1, 2009): 413–19. http://dx.doi.org/10.4141/cjss08063.

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Applying ultrasound energy to soil-water suspensions (sonication) is an established method of determining the size distributions of soil primary mineral particles and associated organic matter. The size distributions may vary, however, with sonication input energy and soil type. The objective of this study was to determine the effects of sonication input energy on the size distributions of soil mineral particles and organic matter for a range of soil textures and carbon contents typical of agricultural soils in southwestern Ontario. The soils included a Brookston clay loam, a Brookston clay, a Huron silt loam, a Perth silt loam and a Harrow sandy loam. All soils were under no-tillage management. Nine sonication energies ranging from 50 to 1500 J mL–1 were applied to soil-water suspensions (1:4 mass ratio), and the soil particle size distribution results were compared with those obtained using the standard chemical dispersion (pipette) method. The three medium- and coarse-textured soils (Huron, Perth, Harrow) required about 250 J mL–1 for complete dissociation of soil aggregates, while the two fine-textured soils (Brookston) required sonication energies of 600-750 J mL–1. Increasing sonication energy increased the amount of soil organic carbon (SOC) measured in the clay-size fraction and decreased the amounts in the sand and silt fractions. Therefore, accurate determinations of particle size distribution and SOC contents require an initial assessment of the amount of sonication energy required for the complete dispersion of the particle size fractions. For the Brookston clay loam and Brookston clay soils, 40–52% less particulate SOC was found in the sand fraction at 750 J mL–1 sonication energy than that obtained using the standard pipette method, indicating particle size reduction by sonication of particle organic matter. It should be noted that the sand-size SOC typically represents a small fraction. Furthermore, sonication had a minor effect on the SOC content of the clay fraction. It was concluded that sonication is a viable technique for determining the size distribution of soil primary mineral particles, as well as the amount of SOC associated with the silt and clay fractions. Key words: Sonication, ultrasound energy, particle size distribution, organic carbon fractionation, clay soil

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BEDNYAKOV, V. A., A. A. GRINYUK, G. I. LYKASOV, and M. POGHOSYAN. "ROLE OF GLUONS IN SOFT AND SEMI-HARD MULTIPLE HADRON PRODUCTION IN pp COLLISIONS AT LHC." International Journal of Modern Physics A 27, no. 08 (March 30, 2012): 1250042. http://dx.doi.org/10.1142/s0217751x1250042x.

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Hadron inclusive spectra in pp collisions are analyzed within the modified quark–gluon string model including both the longitudinal and transverse motion of quarks in the proton in the wide region of initial energies. The self-consistent analysis shows that the experimental data on the inclusive spectra of light hadrons like pions and kaons at ISR energies can be satisfactorily described at transverse momenta not larger than 1–2 GeV /c. We discuss some difficulties to apply this model at energies above the ISR and suggest to include the distribution of gluons in the proton unintegrated over the internal transverse momentum. It leads to an increase in the inclusive spectra of hadrons and allows us to extend the satisfactory description of the data in the central rapidity region at energies higher than ISR.

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Demirel, Ali Ihsan. "Magnetic Relaxation and Flux Creep in Superconducting YBCO Thin Films." Modern Physics Letters B 17, no. 20n21 (September 10, 2003): 1075–80. http://dx.doi.org/10.1142/s0217984903006104.

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In this work, the temperature dependence of the magnetic relaxation in samples of YBa 2 Cu 3 O 7 (YBCO) thin films of two different qualities grown on MgO by metal organic chemical deposition technique (MOCVD) is measured in the range of 4.2–80 K using an initial applied magnetic field of 0.1 T. The relaxation data are analyzed in terms of a single effective activation energy and then more correctly of a distribution of activation energies. The single activation energies extracted are in broad agreement with published results.

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Wolschin, Georg. "Local Thermalization of Gluons in a Nonlinear Model." Nonlinear Phenomena in Complex Systems 23, no. 1 (April 14, 2020): 72–78. http://dx.doi.org/10.33581/1561-4085-2020-23-1-72-78.

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Analytic solutions of a nonlinear boson diffusion equation account for the fast local equilibration of gluons in relativistic heavy-ion collisions using schematic initial conditions. The solutions describe the time-dependent approach to the Bose-Einstein equilibrium distribution with a local equilibration time of τeq ≈ 0.1 fm/c and central temperatures of the order of 500 – 600 MeV in the initial stages of Pb-Pb collisions at energies reached at the Large Hadron Collider (LHC).

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Agafonov, A. I. "Finding the boson-number distributions in superconducting thin-film rings." International Journal of Modern Physics B 28, no. 32 (December 14, 2014): 1450233. http://dx.doi.org/10.1142/s0217979214502336.

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A theory of the infrared (IR)-field-induced single-photon generation by the narrow thin-film superconducting rings made of the isotropic s-wave pairing type-II superconductors is presented. It is shown that statistical measurements of the energies of photons emitted by the same current-carrying ring prepared initially in the same quantum state, allow to find the number distribution of Cooper pairs in the superconductor.

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Maintas, X. N., F. K. Diakonos, G. D. Galanopoulos, N. K. Kaplis, C. I. Papoulias, and H. E. Tsagkarakis. "Bound state effects in transverse momentum parton distributions." HNPS Proceedings 15 (January 1, 2020): 225. http://dx.doi.org/10.12681/hnps.2642.

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We use a non-gaussian intrinsic transverse momentum distribution, associated with the wavefunction of the partonic ground state inside the proton, to calculate the production of π0 with intermediate transverse momentum values in p − p collisions at high energies. It is shown that a perfect description of the experimental data for different experiments is achieved using an almost constant value for the mean transverse momentum of the initial partons, compatible with Heisenberg’s uncertainty relation (⟨kT ⟩ ≈ 0.3 GeV ). Our analysis suggests the presence of a non-vanishing, non-perturbative contribution from partonic bound states to the pp → πo(γ) + X and pp → p + X cross section.

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Abdalla, Ahmed Mohamed. "Rapidity Distribution of Charged Pions From Pb+Pb and Au+Au Central Collisions." JOURNAL OF ADVANCES IN PHYSICS 12, no. 1 (July 30, 2016): 4153–60. http://dx.doi.org/10.24297/jap.v12i1.167.

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Rapidity distributions for charged pions produced from central collisions Pb+Pb and Au+Au at (b â‰¤ 3.4 fm.) in range of energy 2 GeV up to Â = 200 GeV are investigated. The experimental results are studied Â in terms of the Ultra-relativistic Quantum Molecular Dynamic Model Ur-QMD. In general, the model can give suitable predictions of rapidity distributions for production of charged pions from interactions with energies below 160 A GeV. This model is supported the assumption that the onset of de-confinement is located at low energies. It treats the initial nucleon-nucleon interactions within a string-hadronic framework. In addition, it includes effects such as string-string interactions and hadronic re-scattering that expected to be relevant in A+A collisions. There is a kind of similarity for mechanism responsible for production of the two charge states of pions and it can extended to other hadrons. Ultra-relativistic quantum molecular dynamic model give good description on energy dependence for charged pion productions and points of maximum rapidity.Â

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Wang, Shouyi, Zhigang Xu, Chengming Zhang, Jinghan Zhang, Zhongshan Mu, Tianyu Zhao, Yuanyuan Wang, Shuai Gao, Hao Yin, and Ziyun Zhang. "Improved Winter Wheat Spatial Distribution Extraction Using A Convolutional Neural Network and Partly Connected Conditional Random Field." Remote Sensing 12, no. 5 (March 3, 2020): 821. http://dx.doi.org/10.3390/rs12050821.

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Improving the accuracy of edge pixel classification is crucial for extracting the winter wheat spatial distribution from remote sensing imagery using convolutional neural networks (CNNs). In this study, we proposed an approach using a partly connected conditional random field model (PCCRF) to refine the classification results of RefineNet, named RefineNet-PCCRF. First, we used an improved RefineNet model to initially segment remote sensing images, followed by obtaining the category probability vectors for each pixel and initial pixel-by-pixel classification result. Second, using manual labels as references, we performed a statistical analysis on the results to select pixels that required optimization. Third, based on prior knowledge, we redefined the pairwise potential energy, used a linear model to connect different levels of potential energies, and used only pixel pairs associated with the selected pixels to build the PCCRF. The trained PCCRF was then used to refine the initial pixel-by-pixel classification result. We used 37 Gaofen-2 images obtained from 2018 to 2019 of a representative Chinese winter wheat region (Tai’an City, China) to create the dataset, employed SegNet and RefineNet as the standard CNNs, and a fully connected conditional random field as the refinement methods to conduct comparison experiments. The RefineNet-PCCRF’s accuracy (94.51%), precision (92.39%), recall (90.98%), and F1-Score (91.68%) were clearly superior than the methods used for comparison. The results also show that the RefineNet-PCCRF improved the accuracy of large-scale winter wheat extraction results using remote sensing imagery.

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Bakrania, M. R., I. J. Rae, A. P. Walsh, D. Verscharen, A. W. Smith, T. Bloch, and C. E. J. Watt. "Statistics of solar wind electron breakpoint energies using machine learning techniques." Astronomy & Astrophysics 639 (July 2020): A46. http://dx.doi.org/10.1051/0004-6361/202037840.

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Solar wind electron velocity distributions at 1 au consist of a thermal “core” population and two suprathermal populations: “halo” and “strahl”. The core and halo are quasi-isotropic, whereas the strahl typically travels radially outwards along the parallel or anti-parallel direction with respect to the interplanetary magnetic field. Using Cluster-PEACE data, we analyse energy and pitch angle distributions and use machine learning techniques to provide robust classifications of these solar wind populations. Initially, we used unsupervised algorithms to classify halo and strahl differential energy flux distributions to allow us to calculate relative number densities, which are of the same order as previous results. Subsequently, we applied unsupervised algorithms to phase space density distributions over ten years to study the variation of halo and strahl breakpoint energies with solar wind parameters. In our statistical study, we find both halo and strahl suprathermal breakpoint energies display a significant increase with core temperature, with the halo exhibiting a more positive correlation than the strahl. We conclude low energy strahl electrons are scattering into the core at perpendicular pitch angles. This increases the number of Coulomb collisions and extends the perpendicular core population to higher energies, resulting in a larger difference between halo and strahl breakpoint energies at higher core temperatures. Statistically, the locations of both suprathermal breakpoint energies decrease with increasing solar wind speed. In the case of halo breakpoint energy, we observe two distinct profiles above and below 500 km s−1. We relate this to the difference in origin of fast and slow solar wind.

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Pasmanik, D. l., and V. Y. Trakhtengerts. "Spectral characteristics of waves and particles in the model of cyclotron wave-particle interactions near plasmapause." Annales Geophysicae 17, no. 3 (March 31, 1999): 351–57. http://dx.doi.org/10.1007/s00585-999-0351-7.

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Abstract. Further analysis of energetic electron precipitation at the evening sector of magnetosphere is performed. In the framework of the quantitative model of cyclotron wave-particle interactions developed in the previous Pasmanik et al. paper, the case of finite spread over energies of initial energetic electron distribution is studied. The solution for distribution function of energetic electron is found. The energetic spectrum of trapped and precipitating electrons and whistler wave spectrum are analysed.Key words. Magnetospheric physics (energetic particles · precipitating; energetic particles · trapped); · Space plasma physics (wave-particle interactions).

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Gadea, F. X., and J. Durup. "Preliminary Study on Kinetic Energy Distributions of Ar+ Fragments Resulting From Ar3+ Visible Photodissociation." Laser Chemistry 11, no. 2 (January 1, 1991): 95–98. http://dx.doi.org/10.1155/lc.11.95.

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According to a strategy which involves DIM excitonic Hamiltonian, DIM-like transition dipole moments, realistic dynamical propagations with the HWD method (Hemiquantal dynamics with the Whole DIM basis), and the Wigner function to weight the initial conditions, a non-empirical theoretical study of the kinetic energy distribution of the Ar+ photofragments is performed for three total energies. The results illustrate the dominant symmetric stretching motion and the importance of non-adiabatic effects in the Ar3+ dissociation dynamics.

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SALEEV, V. A., and N. P. ZOTOV. "INITIAL STATE SCATTERING AND pT SPECTRA OF MUON PAIRS IN HADRON-NUCLEUS AND NUCLEUS-NUCLEUS COLLISIONS AT HIGH ENERGIES." Modern Physics Letters A 07, no. 07 (March 7, 1992): 545–57. http://dx.doi.org/10.1142/s0217732392000513.

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The muon pair production processes in hadron-nucleus and nucleus-nucleus collisions at high energies are considered using the additive quark model and the perturbation QCD. The transverse momentum dependence of the muon pairs in hadron-nucleus collisions is described. The pT-dependence of the muon pair distributions and their ratio at different values of the total transverse energy ET in heavy nucleus collisions is predicted. A good description of the ET-dependence of [Formula: see text] is provided.

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Li, X. M., B. F. Shen, X. M. Zhang, Z. Y. Jin, and F. C. WANG. "The diagnostics of density distribution for inhomogeneous dense DT plasmas using fast protons." Laser and Particle Beams 26, no. 2 (June 2008): 139–45. http://dx.doi.org/10.1017/s0263034608000165.

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AbstractThe density distribution of inhomogeneous dense deuterium-tritium plasmas in laser fusion is revealed by the energy loss of fast protons going through the plasma. In our simulation of a plasma density diagnostics, the fast protons used for the diagnostics may be generated in the laser-plasma interaction. Dividing a two-dimensional area into grids and knowing the initial and final energies of the protons, we can obtain a large linear and ill-posed equation set for the densities of all grids, which is solved with the Tikhonov regularization method. We find that the accuracy of the set plan with four proton sources is better than those of the set plans with less than four proton sources. Also we have done the density reconstruction especially for four proton sources with and without assuming circularly symmetrical density distribution, and find that the accuracy is better for the reconstruction assuming circular symmetry. The error is about 9% when no noise is added to the final energy for the reconstruction of four proton sources assuming circular symmetry. The accuracies for different random noises to final proton energies with four proton sources are also calculated.

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Wan, Zhen, William H. Oliver, Geraint F. Lewis, Justin I. Read, and Michelle L. M. Collins. "On the origin of the asymmetric dwarf galaxy distribution around andromeda." Monthly Notices of the Royal Astronomical Society 492, no. 1 (December 12, 2019): 456–67. http://dx.doi.org/10.1093/mnras/stz3477.

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ABSTRACT The dwarf galaxy distribution surrounding M31 is significantly anisotropic in nature. Of the 30 dwarf galaxies in this distribution, 15 form a disc-like structure and 23 are contained within the hemisphere facing the Milky Way. Using a realistic local potential, we analyse the conditions required to produce and maintain these asymmetries. We find that some dwarf galaxies are required to have highly eccentric orbits in order to preserve the presence of the hemispherical asymmetry with an appropriately large radial dispersion. Under the assumption that the dwarf galaxies originate from a single association or accretion event, we find that the initial size and specific energy of that association must both be relatively large in order to produce the observed hemispherical asymmetry. However if the association was large in physical size, the very high-energy required would enable several dwarf galaxies to escape from the M31 and be captured by the Milky Way. Furthermore, we find that associations that result in this structure have total specific energies concentrated around $E = V_{\rm esc}^{2} - V_{\rm init}^{2} \sim 200^2$ – $300^2\ \rm {km^2\ s^{-2}}$, implying that the initial velocity and initial position needed to produce the structure are strongly correlated. The overlap of initial conditions required to produce the radial dispersion, angular dispersion, and the planar structure is small and suggests that either they did not originate from a single accretion event, or that these asymmetric structures are short-lived.

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Ljubenov, Vladan, Rodoljub Simovic, Srpko Markovic, and Radovan Ilic. "Photon scattering and reflection in medical diagnostic energy domain." Nuclear Technology and Radiation Protection 23, no. 1 (2008): 31–36. http://dx.doi.org/10.2298/ntrp0801031l.

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The dependence of reflected photons angular and energy distributions on parameter c' - the probability for large-angle scattering - is treated in this paper. The simulation of photon reflection was performed by the FOTELP code for a normal incidence of photons into infinite slabs of common shielding materials, and for the photon initial energies of 20 keV up to 100 keV.

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Kamiński, Marcin, and Michał Strąkowski. "Computer Simulation of Stochastic Energy Fluctuations in Tensile Test of Elasto-Plastic Porous Metallic Material." Energies 13, no. 2 (January 19, 2020): 485. http://dx.doi.org/10.3390/en13020485.

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The main aim of this work is the computational implementation and numerical simulation of a metal porous plasticity model with an uncertain initial microdefects’ volume fraction using the Stochastic Finite Element Method (SFEM) based on the semi-analytical probabilistic technique. The metal porous plasticity model applied here is based on Gurson–Tvergaard–Needleman theory and is included in the ABAQUS finite element system, while the external probabilistic procedures were programmed in the computer algebra system MAPLE 2017. Hybrid usage of these two computer systems enabled the determination of fluctuations in elastic and plastic energies due to initial variations in the ratio of the metal micro-voids, and the calculation of the first four probabilistic moments and coefficients of these energies due to Gaussian distribution of this ratio. A comparison with the Monte-Carlo simulation validated the numerical efficiency of the proposed approach for any level of input uncertainty and for the first four probabilistic characteristics traditionally seen in the experimental series.

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Nastasovic, Aleksandra, and Antonije Onjia. "Surface characterization of polymers by inverse gas chromatography." Journal of the Serbian Chemical Society 72, no. 4 (2007): 403–6. http://dx.doi.org/10.2298/jsc0704403n.

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An inverse gas chromatographic (IGC) study of the sorption properties of macroporous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate), PGME, and PGME modified with ethylene diamine, PGME-en, was presented. At infinite dilution, the thermodynamic parameters of adsorption, the dispersive components of the surface free energies, the acid/base constants and the interaction parameters for the initial and modified copolymer samples were investigated. The adsorption isotherms determined by IGC under conditions of finite surface coverage were used to estimate the surface area, the isosteric heat of adsorption and the adsorption energy distribution on the surface of the initial and modified copolymer samples. .

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Chirkov, P. N., Y. A. Chesnokov, V. A. Maisheev, D. Bolognini, S. Hasan, M. Prest, and E. Vallazza. "Channeling radiation of multi-GeV positrons in single crystals." International Journal of Modern Physics A 31, no. 10 (April 6, 2016): 1650051. http://dx.doi.org/10.1142/s0217751x16500512.

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The process of radiation of 120 GeV positrons moving in a channeling regime in (011) plane of a single crystal was considered. At the beginning on the basis of the theory of nonlinear oscillations, the trajectory of moving positrons at different initial conditions was derived. Then taking into account the nonlinearity of motion, the distribution function over oscillation amplitudes of channeling particles was found. After this, the intensity of radiation at different initial conditions was calculated with the help of two various methods. These results may be useful for comparison with experimental data at positron energies from 100 and more GeV.

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Sahoo, Raghunath, Aditya Nath Mishra, Nirbhay K. Behera, and Basanta K. Nandi. "Charged Particle, Photon Multiplicity, and Transverse Energy Production in High-Energy Heavy-Ion Collisions." Advances in High Energy Physics 2015 (2015): 1–30. http://dx.doi.org/10.1155/2015/612390.

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We review the charged particle and photon multiplicities and transverse energy production in heavy-ion collisions starting from few GeV to TeV energies. The experimental results of pseudorapidity distribution of charged particles and photons at different collision energies and centralities are discussed. We also discuss the hypothesis of limiting fragmentation and expansion dynamics using the Landau hydrodynamics and the underlying physics. Meanwhile, we present the estimation of initial energy density multiplied with formation time as a function of different collision energies and centralities. In the end, the transverse energy per charged particle in connection with the chemical freeze-out criteria is discussed. We invoke various models and phenomenological arguments to interpret and characterize the fireball created in heavy-ion collisions. This review overall provides a scope to understand the heavy-ion collision data and a possible formation of a deconfined phase of partons via the global observables like charged particles, photons, and the transverse energy measurement.

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Dulloo, Abdul R., and Ward S. Diethorn. "Recoil tritium in 304-stainless steel: the initial distribution revisited." Journal of Nuclear Materials 256, no. 2-3 (August 1998): 235–46. http://dx.doi.org/10.1016/s0022-3115(98)00048-8.

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Jacob, Wolfgang, Thomas Dürbeck, Thomas Schwarz-Selinger, and Udo von Toussaint. "Bonding States of Hydrogen in Plasma-Deposited Hydrocarbon Films." C — Journal of Carbon Research 6, no. 1 (January 9, 2020): 3. http://dx.doi.org/10.3390/c6010003.

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We applied temperature-programmed desorption (TPD) spectroscopy to study the bonding of hydrogen in amorphous hydrogenated carbon (a–C:H) films. Typical hard plasma-deposited a–C:H films with an initial hydrogen content (H/(H+C)) of about 30% were used as samples. About 85% of the initial hydrogen content is released in the form of H2, the rest in the form of hydrocarbons. Using a temperature ramp of 15 K/min, release of hydrogen starts at about 600 K with a first peak at about 875 K and a broad shoulder around 1050 K. The peak positions depend on the temperature ramp. This fact was exploited to determine the pre-exponential factor for an analytic analysis of the release spectra. This analysis revealed a pre-exponential factor of ν = 1 × 10 16 1/s, which deviates significantly from the frequently assumed prefactor 1 × 10 13 1/s. This higher prefactor leads to a shift in the determined binding energies by about +0.5 eV. Standard TPD measurements with linear temperature ramps up to 1275 K were complemented by so-called “ramp and hold” experiments with linear ramps up to certain intermediate temperatures and holding the samples for different times at these temperatures. Such experiments provide valuable additional data for investigation of the thermal behavior of the investigated films. Our experiments prove that the width of the hydrogen release spectrum is determined by a distribution of binding energies rather than release kinetics or diffusive effects. This binding energy distribution has a peak at about 3.1 eV and a shoulder at higher energies extending from about 3.6 to 3.9 eV.

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Dhaundiyal, Alok, Suraj B. Singh, Muammel M. Hanon, and Norbert Schrempf. "Clayton Copula as an Alternative Perspective of Multi-Reaction Model." Environmental and Climate Technologies 22, no. 1 (November 1, 2018): 83–106. http://dx.doi.org/10.2478/rtuect-2018-0006.

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Abstract This study proposes to assess the effect of some relevant parameters of biomass pyrolysis on the numerical solutions of nthorder distributed activation energy model (DAEM) or multi reaction model (MRM). The two-step process mechanisms of pyrolysis is described by replacing the initial distribution function of f (E) with the Clayton copula. The upper limit (E∞) of ‘dE’ integral, activation energy (A), heating rate (m), and the shape and scale parameters of bivariate distribution function. Temperature ramp rate is assumed to vary linearly with time. Thermo-analytical data is obtained with the help of thermogravimetric (TG) analysis. Asymptotic technique is adopted to approximate double exponential and bivariate distribution function f (E1, E2), where E1and E2are the activation energies for bivariate scheme.

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Karimianfard, Hossein, and Hossein Haghighat. "An initial-point strategy for optimizing distribution system reconfiguration." Electric Power Systems Research 176 (November 2019): 105943. http://dx.doi.org/10.1016/j.epsr.2019.105943.

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Batmunkh, Munkhbaatar, Alexander Bugay, Lkhagvaa Bayarchimeg, and Oidov Lkhagva. "Radiation Damage to Nervous System: Designing Optimal Models for Realistic Neuron Morphology in Hippocampus." EPJ Web of Conferences 173 (2018): 05004. http://dx.doi.org/10.1051/epjconf/201817305004.

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The present study is focused on the development of optimal models of neuron morphology for Monte Carlo microdosimetry simulations of initial radiation-induced events of heavy charged particles in the specific types of cells of the hippocampus, which is the most radiation-sensitive structure of the central nervous system. The neuron geometry and particles track structures were simulated by the Geant4/Geant4-DNA Monte Carlo toolkits. The calculations were made for beams of protons and heavy ions with different energies and doses corresponding to real fluxes of galactic cosmic rays. A simple compartmental model and a complex model with realistic morphology extracted from experimental data were constructed and compared. We estimated the distribution of the energy deposition events and the production of reactive chemical species within the developed models of CA3/CA1 pyramidal neurons and DG granule cells of the rat hippocampus under exposure to different particles with the same dose. Similar distributions of the energy deposition events and concentration of some oxidative radical species were obtained in both the simplified and realistic neuron models.

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Mikkola, Seppo. "Numerical Simulations of Encounters of Hard Binaries." Symposium - International Astronomical Union 113 (1985): 335–38. http://dx.doi.org/10.1017/s0074180900147564.

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Results from numerical integrations of random binary-binary encounters have been used to obtain various cross-sections and outcome distributions for the four-body scattering. The initial orbital elements were chosen randomly except the Kepler-energies for which various selected values were used. Rough estimates for mass effects were obtained by simulating encounters of binaries with unequal component masses.We developed a semi-analytical theory for obtaining the types and energies of the outcome configurations. The theory contains some adjustable parameters, the values of which we deduced by comparing the theory and experiments.The energy transfer rate by collisions (=outcome is not two binaries) dominates over that due to fly-by's by an order of magnitude, provided that the binaries are hard. The formation of a hierarchical three-body system is fairly common. In a collision of energetically similar very hard binaries the probability is about 20 percent, while it is greater than 50 percent if the binding energies differ by a factor of more than four.

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Journal articles on the topic 'Distribution energie initiale'

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