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time evolution of Artificial Plasma Cloud in Atmospheric Environment

Plasma Science and Technology 2004年第4期6卷 2427-2432页

作者：陆启明杨维纮刘万东 Department of Modern Physics University of Science and Technology of ChinaHefei 230027China Department of Modern Physics University of Science and Technology of ChinaHefei 230027Chinay analyzing the time evolution of artificial plasma cloud in the high altitude of atmospheric environment we found that there are two zones an exponential attenuation zone and a linearly attenuating zone existing in the spatial distribution of electron density of the artificial plasma clouds. The plasma generator's particle flux density only contributes to the exponential attenuation zone and has no effect on the linear attenuation zone. The average electron density in the linear attenuation zone is about 10-5 of neutral particle density and can diffuse over a wider area. The conclusion will supply some valuable references to the research of electromagnetic wave and artificial plasma interaction the plasma invisibleness research of missile and special aerocraft and the design of artificial plasma source.

By analyzing the time evolution of artificial plasma cloud in the high altitude of atmospheric environment, we found that there are two zones, an exponential attenuation zone and a linearly attenuating zone, existing in the spatial distribution of electron density of the artificial plasma clouds. The plasma generator's particle flux density only contributes to the exponential attenuation zone, and has no effect on the linear attenuation zone The average electron density in the linear attenuation zone is about 10-5 of neutral particle density, and can diffuse over a wider area. The conclusion will supply some valuable references to the research of electromagnetic wave and artificial plasma interaction, the plasma invisibleness research of missile and special aerocraft, and the design of artificial plasma source.

关键词： artificial plasma time evolution plasma generator

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time evolution of negative binomial optical field in a diffusion channel

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Chinese Physics B 2015年第9期24卷 97-100页

作者：刘堂昆吴盼盼单传家刘继兵范洪义 College of Physics and Electronic Science Hubei Normal University Department of Material Science and Engineering University of Science and Technology of China

We find the time evolution law of a negative binomial optical field in a diffusion channel. We reveal that by adjusting the diffusion parameter, the photon number can be controlled. Therefore, the diffusion process ca... 详细信息

关键词： negative binomial optical field time evolution diffusion channel integration within an ordered product(IWOP) of operators

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time evolution and Squeezing of Degenerate and Non-degenerate Coupled Parametric Down-Conversion with Driving Term

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Communications in Theoretical Physics 2009年第3期51卷 514-518页

作者： LI Jiang-Fan FANG Jia-Yuan XIAO Fu-Liang LIU Xin-Hai WANG Cheng-Zhi School of Physics and Electronic Science Changsha University of Science and Technology Changsha 410076 China

By properly selecting the time-dependent unitary transformation for the linear combination of the number operators, we construct a time-dependent invariant and derive the corresponding auxiliary equations for the degenerate and non-degenerate coupled parametric down-conversion system with driving term. By means of this invariant and the Lewis-Riesenfeld quantum invariant theory, we obtain closed formulae of the quantum state and the evolution operator of the system. We show that the time evolution of the quantum system directly leads to production of various generalized one- and two-mode combination squeezed states, and the squeezed effect is independent of the driving term of the Hamiltonian. In some special cases, the current solution can reduce to the results of the previous works.

关键词： coupled parametric down-conversion time evolution Lewis-Riesenfeld invariant theory Schrodinger equation squeezed states

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Quantitative conditions for time evolution in terms of the von Neumann equation

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Science China(Physics,Mechanics & Astronomy) 2018年第7期61卷 54-60页

作者： WenHua Wang HuaiXin Cao ZhengLi Chen Lie Wang School of Ethnic Education Shaanxi Normal University Xi'an 710062 China School of Mathematics and In Cbrmatton Sctence Shaanxi Normal University Xi 'an 710062 China

The adiabatic theorem describes the time evolution of the pure state and gives an adiabatic approximate solution to the Schrrdinger equation by choosing a single eigenstate of the Hamiltonian as the initial state. In quantum systems, states are divided into pure states （unite vectors） and mixed states （density matrices, i.e., positive operators with trace one）. Accordingly, mixed states have their own corresponding time evolution, which is described by the von Neumann equation. In this paper, we discuss the quantitative conditions for the time evolution of mixed states in terms of the von Neumann equation. First, we introduce the definitions for uniformly slowly evolving and δ-uniformly slowly evolving with respect to mixed states, then we present a necessary and sufficient condition for the Hamiltonian of the system to be uniformly slowly evolving and we obtain some upper bounds for the adiabatic approximate error. Lastly, we illustrate our results in an example.

关键词： quantitative condition time evolution uniformly slowly evolving δ-uniformly slowly evolving upper bound

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Investigations on the time evolution of the plasma density in argon electron-beam plasma at intermediate pressure

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Plasma Science and Technology 2017年第3期19卷 47-53页

作者： Xiaoyan BAI Chen CHEN Hong LI Wandong LIU KTX Laboratory and Department of Modem Physics University of Science and Technology of China Hefei 230026 People＇s Republic of China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear Technology Xi＇an 710024 People＇s Republic of China

The time evolution of the argon electron-beam plasma at intermediate pressure and low electron beam intensily was *** applying the amplitude modulation with the frequency of 20 Hz on the stable beam current,the plasma evolution was studied.A Faraday cup was used for the measurement of the electron beam current and a single electrostatic probe was used for the measurement of the ion *** results indicated that the ion current was in phase with the electron beam current in the pressure range from 200 Pa to 3000 Pa and in the beam current range lower than 20 mA,the residual density increased approximately linearly with the maximum density in the log-log plot and the fitting coefficient was irrelative to the *** then three kinds of kinetic models were developed and the simulated results given by the kinetic model,without the consideration of the excited atoms,mostly approached to the experimental *** indicated that the effect of the excited atoms on the plasma density can be ignored at intermediate pressure and low electron beam current intensity,which can greatly simplify the kinetic *** the *** decrease of the plasma density when the beam current was suddenly off was studied based on the simplified model and it was found that the decease characteristic at intermediate pressure was approximate to the one at high pressure at low electron beam intensity,which was in good accordance with the experimental results.

关键词： electron-beam plasma kinetic model time evolution residual density phase lag

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Restudy on Dark Matter time-evolution in the Littlest Higgs Model with T-Parity

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Communications in Theoretical Physics 2008年第11期50卷 1211-1218页

作者： QIAO Qing-Peng TANG Jian LI Xue-Qian Department of Physics Nankai University Tianjin 300071 China

Following previous study, in the littlest Higgs model （LHM）, the heavy photon is supposed to be a possiL dark matter candidate and its relic abundance of the heavy photon is estimated in terms of the Boltzman- Lee-Weinba time-evolution equation. The effect of the T-parity violation is also considered. Our calculations show that when Higmass MH taken to be 300 GeV and do not considering T-parity violation, only two narrow ranges 133 〈 MAH 〈 135 Ge and 167 〈 MAH〈 169 GeV are tolerable with the current astrophysical observation and if 135 〈 MAH 〈 167 GeV there must at least exist another species of heavy particle contributing to the cold dark matter. As long as the T-pari; can be violated, the heavy photon can decay into regular standard model particles and would affect the dark matt abundance in the universe, we discuss the constraint on the T-parity violation parameter based on the present dat Direct detection prospects are also discussed in some detail.

关键词： little Higgs dark matter time evolution

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Wobbling Motion in the Even-even Nucleus

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原子核物理评论 2024年第1期41卷 200-206页

作者： SUN Bowen JI Yingzhi CHEN Qibo Department of Physics East China Normal UniversityShanghai 200241China

The recent progresses on the wobbling motion are briefly *** far 17 wobbling candidates have been reported in odd-A and even-even nuclei that spread over A≈100,130,160 and 190 mass *** two-quasiparticle configuration wobbling in ^(130)Ba and the wobbling motion in a triaxial rotor are taken as examples in this paper to show the wobbling motion in even-even *** the ^(130)Ba,the wobbling are investigated based on the combination of the covariant density functional theory(CDFT)and the particle rotor model(PRM).The CDFT provides crucial information on the configuration and deformation parameters of observed bands,serving as input for PRM *** corresponding experimental energy spectra and electromagnetic transition probabilities are *** analysis of the angular momentum geometry reveals the enhanced stability of transverse wobbling of a two-quasiparticle configuration compared to a single-quasiparticle *** the triaxial rotor,the time evolution of wobbling motion is explored through the solution of Euler *** investigation yields valuable insights into the evolution of orientation angles(φ and θ)and angular momentum ***,the study reveals that low-energy states of a triaxial rotor predominantly exhibit wobbling motion around the intermediate ***,an increase in excitation energy corresponds to a prolonged period of intermediate axis wobbling ***,a contrasting trend is observed in the case of long axis wobbling,where an increase in excitation energy leads to a decrease in the wobbling period.

关键词： wobbling motion even-even nucleus two-quasiparticle time evolution

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A comparison between artificial neural network algorithms and empirical equations applied to submerged weir scour evolution prediction

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International Journal of Sediment Research 2023年第1期38卷 105-114页

作者： Dawei Guan Jingang Liu Yee-Meng Chiew Jian-Hao Hong Liang Cheng Key Laboratory of Ministry of Education for Coastal Disaster and Protection Hohai University School of Civil and Environment Engineering Nanyang Technological University Sustainability Center Nanhua University School of the Environment and Safety Engineering Jiangsu University

Estimating the time evolution of a local scour hole downstream of submerged weirs can help determine the maximum scour depth and length and is essential to designing submerged weir *** the current study, artificial neural networks with a backpropagation learning algorithm were used to estimate the temporal variation of scour profiles downstream of submerged weirs under clear water conditions. Physical factors, such as the flow condition, weir size, and sediment characteristics, are general scour considerations. Two sets of data combinations, namely original and non-dimensional data, were utilized in developing the backpropagation network(BPN) model. Using the data combinations and a trial-and-error method, the appropriate number of hidden neurons in the model architecture was determined. The results indicated that using non-dimensional variables as inputs in estimating the time evolution of scour holes downstream of a submerged weir is more suitable for the BPN model. Comparisons of the prediction results of the BPN model and an empirical regression formula revealed that the BPN model was more accurate and more direct in predicting the temporal variation of the local scour hole profile. In addition, sensitivity analysis showed that the dimensionless time exerted the most significant impact on the time evolution of the non-dimensional scour hole profile.

关键词： Submerged weir Scour profile Artificial neural networks (ANNs) time evolution Backpropagation

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Density-Density Propagator of the Luttinger Model of Spin-Half Fermions after an Interaction Quench

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Communications in Theoretical Physics 2012年第8期58卷 292-294页

作者：周宗立袁兴红穆姝慧赵艳娄萍章国顺 School of Science Anhui Agricultural University School of Physics and Material Science Anhui University School of Life Sciences Anhui Medical University

Motivated by recent research achievement of quantum interacting systems in non-equilibrium, we consider a Luttinger model with a suddenly switched-on interaction proposed by Cazalilla [M.A. Cazalilla, Phys. Rev. Lett. 97 (2006) 156403]. In order to compare with real systems, we extend Cazalilla's scenario to the spinful system. To find the influence of initial states on the time evolution of some non-equilibrium systems, we mainly focus on the density-density propagator. By comparison and analysis, we discover the different behavior of this non-equilibrium system. Further, it is found that the propagator saves strong memory of initial state, and the effects of right-left interaction cancel out in total density-density propagator.

关键词： Luttinger model of spin-half fermions interaction quench time evolution density-density propagator

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Casimir Effect via a Generalized Matsubara Formalism

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Journal of Applied Mathematics and Physics 2022年第12期10卷 3601-3615页

作者： Adolfo P. C. Malbouisson Centro Brasileiro de Pesquisas Físicas/MCTI Rio de Janeiro Brazil

We investigate the Casimir effect in the context of a nontrivial topology by means of a generalized Matsubara formalism. This is performed in the context of a scalar field in D Euclidean spatial dimensions with d compactified dimensions. The procedure gives us the advantage of considering simultaneously spatial constraints and thermal effects. In this sense, the Casimir pressure in a heated system between two infinite planes is obtained and the results are compared with those found in the literature.

关键词： Cavities Simple Systems time evolution

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