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An embedded electron current layer observed at the edge of the plasma sheet in the Earth’s magnetotail

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Earth and Planetary Physics 2025年第1期9卷 148-158页

作者： ChenChen Zhan RongSheng Wang QuanMing Lu san Lu XinMin Li Deep Space Exploration Laboratory/School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China Chinese Academy of Sciences(CAS)Center for Excellence in Comparative Planetology/CAS Key Laboratory of Geospace Environment/Anhui Mengcheng National Geophysical Observatory University of Science and Technology of ChinaHefei 230026China Collaborative Innovation Center of Astronautical Science and Technology Harbin 150001China

The formation of an embedded electron current sheet within the magnetotail plasma sheet has been poorly *** this article,we present an electron current layer detected at the edge of the magnetotail plasma *** ions were demagnetized inside the electron current layer,but the electrons were still frozen in with the magnetic field ***,this decoupling of ions and electrons gave rise to a strong Hall electric field,which could be the reason for the formation of the embedded thin current *** magnetized electrons,the absence of the nongyrotropic electron distribution,and negligible energy dissipation in the layer indicate that magnetic reconnection had not been triggered within the embedded thin current *** highly asymmetric plasma on the two sides of the current layer and low magnetic shear across it could suppress magnetic *** observations indicate that the embedded electric current layer,probably generated by the Hall electric field,even down to electron scale,is not a sufficient condition for magnetic reconnection.

关键词： magnetotail plasma sheet magnetic reconnection

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二维Janus LuClI的铁谷特性研究

原子与分子物理学报 2025年第2期42卷 159-168页

作者：朱靖欣郭三栋西安邮电大学电子工程学院西安710121

铁谷材料由于其固有的铁磁性质,可以产生自发谷极化,从而实现谷自由度的操纵.不同的谷极化状态为铁谷材料在信息传递领域的应用提供了可能性.在本文的工作中,采用了可靠的第一性原理计算方法,证明了Janus单层LuClI的动力学、力学和热力... 详细信息

铁谷材料由于其固有的铁磁性质,可以产生自发谷极化,从而实现谷自由度的操纵.不同的谷极化状态为铁谷材料在信息传递领域的应用提供了可能性.在本文的工作中,采用了可靠的第一性原理计算方法,证明了Janus单层LuClI的动力学、力学和热力学稳定性.发现Janus单层LuClI是一种有潜力的铁谷材料,它有着50.927 meV的谷劈裂.当Lu原子磁矩方向(平面外)发生颠倒时,可以实现谷极化翻转.还计算了Janus单层LuClI在布里渊区中的Berry曲率分布,主要集中在-K和K谷,可以实现反常谷霍尔效应.当电子关联强度比较小时,Janus单层LuClI的易磁化轴将指向面内,从而失去自发谷极化.尽管如此,利用应变调控可以使磁化方向从面内转向面外,从而产生谷极化.此外,Janus单层LuClI同时具有面内和面外压电响应,计算得到的面内压电应变系数d11大于大部分已有二维材料的计算值,而面外压电系数d31非常小.这为通过压电效应调控谷载流子提供了可能性.

关键词：铁谷材料压电第一性原理计算

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Lattice design for a hybrid multi-bend achromat light source

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Nuclear Science and Techniques 2020年第7期31卷 55-64页

作者： Eun-san Kim Department of Accelerator Science Korea University Sejong CampusSejong 30019Korea

We present a lattice design and beam dynamics analysis for a 4 GeV low-emittance,high-brilliance synchrotron light *** lattice consisted of 26 six-bend achromats with 26 long and 26 short straight *** present the design results for a hybrid multi-bend achromat(HMBA)lattice with a natural emittance of 168 pm and circumference of 729.3 *** cell had 4 longitudinal gradient bendings,2 combined bendings,14 quadrupoles,and 2 families of *** lattice was designed to beflexible to provide both nonzero and zero dispersion functions in the long straight *** two straight sections in each cell had lengths of 5.6 and 1.2 *** ensure sufficient injection,we optimized the design lattice and dynamic *** investigated the dynamic aperture in the lattice with machine errors,and the results showed that the lattice design provides sufficient dynamic aperture after COD correction for beam *** present the results of an injection scheme that demonstrates the space in the injection section and the particle motions of the injected *** also present the results of beam tracking after the beam injection to examine the characteristics of the beam *** designed HMBA lattice was well optimized in terms of the beam parameters and brilliance as an intermediate light source at 4 GeV and a circumference of 729.3 m.

关键词： injection beam lattice

Improved adaptive pruning algorithm for least squares support vector regression

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Journal of Systems Engineering and Electronics 2012年第3期23卷 438-444页

作者： Runpeng Gao Ye san Control and Simulation Center Harbin Institute of TechnologyHarbin 150001P.R.China

As the solutions of the least squares support vector regression machine （LS-SVRM） are not sparse, it leads to slow prediction speed and limits its applications. The defects of the ex- isting adaptive pruning algorithm for LS-SVRM are that the training speed is slow, and the generalization performance is not satis- factory, especially for large scale problems. Hence an improved algorithm is proposed. In order to accelerate the training speed, the pruned data point and fast leave-one-out error are employed to validate the temporary model obtained after decremental learning. The novel objective function in the termination condition which in- volves the whole constraints generated by all training data points and three pruning strategies are employed to improve the generali- zation performance. The effectiveness of the proposed algorithm is tested on six benchmark datasets. The sparse LS-SVRM model has a faster training speed and better generalization performance.

关键词： least squares support vector regression machine (LS- SVRM) pruning leave-one-out (LOO) error incremental learning decremental learning.

RBF neural network based on q-Gaussian function in function approximation

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Frontiers of Computer Science 2011年第4期5卷 381-386页

作者： Wei ZHAO Ye san Control and Simulation Center Harbin Institute of Technology Harbin 150001 China

To enhance the generalization performance of radial basis function （RBF） neural networks, an RBF neural network based on a q-Gaussian function is proposed. A q-Gaussian function is chosen as the radial basis function of the RBF neural network, and a particle swarm optimization algorithm is employed to select the parameters of the network. The non-extensive entropic index q is encoded in the particle and adjusted adaptively in the evolutionary process of population. Simulation results of the function approximation indicate that an RBF neural network based on q-Gaussian function achieves the best generalization performance.

关键词： radial basis function (RBF) neural network,q-Gaussian function particle swarm optimization algo-rithm function approximation

Gender, Intra-Household Dynamics, and Household Hurricane Preparedness: An Exploratory Study Employing a Dyadic Interview Approach

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International Journal of Disaster Risk Science 2018年第1期9卷 16-27页

作者： Li-san Hung Department of Geography Pennsylvania State University

This exploratory study targets married, heterosexual couples living in Sarasota County, Florida and uses a dyadic interview approach to understand how the interactions of married couples, or intra-household dynamics,could affect household hurricane preparedness. Interview results reveal that couples consider household hurricane preparedness to be a joint process between husband and wife, but in many cases, partners do not have the same opinions about these preparations. This study also shows the relations between household hurricane preparedness and household division of labor, and how the tendency of wives to prioritize relational preparedness activities could be an answer to understanding why some quantitative studies show that females have lower preparedness levels than males. Other potential problems with this previous research, including the selection of survey participants and the measurement of household hurricane preparedness, are likewise discussed.

关键词： Dyadic interviews Gender Household decision making Household hurricane preparedness Intra-household dynamics

MULTIPLE POSITIVE SOLUTIONS FOR QUASILINEAR ELLIPTIC PROBLEMS INVOLVING CONCAVE-CONVEX NONLINEARITIES AND MULTIPLE HARDY-TYPE TERMS

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Acta Mathematica Scientia 2013年第5期33卷 1314-1328页

作者： Tsing-san HSU Center for General Education Chang Gung University

In this paper, we deal with the existence and multiplicity of positive solutions for the quasilinear elliptic problem -△pu-∑i=1^kμi｜u｜^p-2/｜x-ai｜p^u=｜u｜^p^＊-2u＋λ｜u｜^q-2u,x∈Ω,where Ω belong to R^N（N ≥ 3） is a smooth bounded domain such that the different points ai∈Ω,i= 1,2,...,k,0≤μi〈μ^-=（N-p/p）^p,λ〉0,1≤q〈p,and p^＊=p^N/*** results depend crucially cn the parameters λ,q and μi for i=1,2,...,k.

关键词： multiple positive solutions concave-convex nonlinearities multiple Hardy- type terms

On the Asymptotic Uniformity of the Quantization Error for Moran Measures on R^1

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Acta Mathematica Sinica,English Series 2019年第9期35卷 1520-1540页

作者： san Guo ZHU School of Mathematics and Physics Jiangsu University of Technology

Let E be a Moran set on R1 associated with a bounded closed interval J and two sequences(nk)k =1 ^∞ and(Ck =(ck,j)j=1)^nk)k≥1. Let μ be the Moran measure on E associated with a sequence(Pk)k≥1 of positive probability vectors with Pk =(pk,j)j =1,^nk, k ≥ 1. We assume that k≥1 1≤j≤nk^inf min Ck,j>0,k≥1 1≤j≤nk^inf minCk,j>0,k≥1 1≤j≤nk ^inf min pk,j>0. For every n ≥ 1, let αn be αn n optimal set in the quantization for μ of order r ∈(0,∞) and{Pa(αn)}a∈α∈an an arbitrary Voronoi partition with respect to αn. We write Iα(α,μ):=∫Pα(αn)^d(x,αn)^τ dμ(x),α∈αn;J(αn,μ):=α∈αn^minⅠα(α,μ),J(αn,μ):=α∈αn^max Ⅰα(α,μ).We show that J(αn,μ),J(αn,μ) and en^r,r(μ)-en^r +1,r(μ) are of the same order as 1/n en^r ,r(μ), where en^r ,r(μ):=∫d(x,αn)^r dμ(x) is the nth quantization error for μ of order r. In particular, for the class of Moran measures on R1, our result shows that a weaker version of Gersho’s conjecture holds.

关键词： Moran measures quantization error Voronoi partition asymptotic uniformity

Aerodynamic design on high-speed trains

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Acta Mechanica Sinica 2016年第2期32卷 215-232页

作者： san-san Ding Qiang Li Ai-Qin Tian Jian Du Jia-Li Liu School of Mechanical Electronic and Control EngineeringBeijing Jiaotong University CSR Qingdao Sifang Locomotive & Rolling Stock Co. Ltd.

Compared with the traditional train,the operational speed of the high-speed train has largely improved,and thedynamicenvironmentofthetrainhaschangedfromoneof mechanical domination to one of aerodynamic *** aerodynamic problem has become the key technological challenge of high-speed trains and significantl affects the economy,environment,safety,and *** this paper,the relationships among the aerodynamic design principle,aerodynamic performance indexes,and design variables are firs studied,and the research methods of train aerodynamics are proposed,including numerical simulation,a reducedscale test,and a full-scale *** schemes of train aerodynamics involve the optimization design of the streamlined head and the smooth design of the body *** design of the streamlined head includes conception design,project design,numerical simulation,and a reduced-scale *** design of the body surface is mainly used for the key parts,such as electric-current collecting system,wheel truck compartment,and *** aerodynamic design method established in this paper has been successfully applied to various high-speed trains（CRH380A,CRH380 AM,CRH6,CRH2 G,and the Standard electric multiple unit（EMU）） that have met expected design *** research results can provide an effective guideline for the aerodynamic design of high-speed trains.

关键词： High-speed train Aerodynamic design Optimization design Smooth design