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Simplified Analysis for Leaky Modes in Planar Optical Waveguides

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Chinese Physics Letters 1999年第6期16卷 413-414页

作者： CAO Zhuang-qi qiU Limlin shen qi-shun DOU Xiao-ming CHEN Ying-li Department of Applied Physics Shanghai Jiaotong UniversityShanghai 200030

In combination with the transfer matrix method and the concept of an equivalent attenuated coefficient,a first-order perturbation theory is proposed to study the leaky modes in planar optical *** analytical expressions of the perturbed propagation constants are presented in a more explicit and general manner compared to the existing theory.

关键词： theory. perturbation constants

Determination of the Refractive Index Profile of a Polymer Waveguide by Photobleaching

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Chinese Physics Letters 2000年第6期17卷 433-434页

作者： SHAN Ji-Xiang shen qi-shun ZHANG Ai-Hua CAO Zhuang-qi CHEN Ying-Li Department of Applied Physics Jiao Tong UniversityShanghai 200030

The shrinkage effect of polymer films,which was demonstrated in our photobleaching experiment,can be fitted approximately by an exponentially decaying *** taking the shrinkage effect into account,the index profile of the polymer waveguide was determined to be a Fermi function with the help of the m-line method and the exact transfer matrix theory.

关键词： function waveguide Waveguide

On the half-quantized Hall conductance of massive surface electrons in magnetic topological insulator films

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 127-136页

作者： Rui Chen shun-qing shen Department of Physics The University of Hong KongHong Kong 999077China Department of Physics Hubei UniversityWuhan 430062China

In topological insulators,massive surface states resulting from local symmetry breaking were thought to exhibit a half-quantized Hall conductance,obtained from the low-energy effective model in an infinite Brillouin *** a lattice model,the surface band is composed of a combination of surface states and bulk *** massive surface states alone may not be enough to support an exact one-half quantized surface Hall conductance in a finite Brillouin zone and the whole surface band always gives an integer quantized Hall conductance as enforced by the TKNN *** explore this,we investigate the band structures of a lattice model describing the magnetic topological insulator film that supports the axion insulator,Chern insulator,and semi-magnetic topological insulator *** reveal that the gapped and gapless surface bands in the three phases are characterized by an integer-quantized Hall conductance and a half-quantized Hall conductance,*** propose an effective model to describe the three phases and show that the low-energy dispersion of the surface bands inherits from the surface Dirac *** gapped surface band manifests a nearly half-quantized Hall conductance at low energy near the center of Brillouin zone,but is compensated by another nearly half-quantized Hall conductance at high energy near the boundary of Brillouin zone because a single band can only have an integer-quantized Hall *** gapless band hosts a zero Hall conductance at low energy but is compensated by another half-quantized Hall conductance at high energy,and thus the half-quantized Hall conductance can only originate from the gapless ***,we calculate the layer-resolved Hall conductance of the *** conclusion suggests that the individual gapped surface band alone does not support the half-quantized surface Hall effect in a lattice model.

关键词： magnetic topological insulator Dirac equation half-quantized Hall conductance

Analytical computation of magnetic field in coil-dominated superconducting quadrupole magnets based on racetrack coils

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Nuclear Science and Techniques 2024年第4期35卷 119-135页

作者： Chuang shen Ying-shun Zhu Fu-San Chen China Spallation Neutron Source Institute of High Energy PhysicsChinese Academy of Sciences1 Zhongziyuan RoadDongguan 523000China Institute of High Energy Physics Chinese Academy of Sciences19B Yuquan RoadBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

Currently,three types of superconducting quadrupole magnets are used in particle accelerators:cos 2θ,CCT,and ***,all three coil configurations have complex spatial geometries,which make magnet manufacturing and strain-sensitive superconductor applications *** with the three existing quadrupole coils,the racetrack quadrupole coil has a simple shape and manufacturing process,but there have been few theoretical *** this paper,the two-dimensional and three-dimensional analytical expressions for the magnetic field in coil-dominated racetrack superconducting quadrupole magnets are *** analytical expressions of the field harmonics and gradient are fully resolved and depend only on the geometric parameters of the coil and current ***,a genetic algorithm is applied to obtain a solution for the coil geometry parameters with field harmonics on the order of 10^(-4).Finally,considering the practical engineering needs of the accelerator interaction region,electromagnetic design examples of racetrack quadrupole magnets with high gradients,large apertures,and small apertures are described,and the application prospects of racetrack quadrupole coils are analyzed.

关键词： Superconducting quadrupole magnet Racetrack coil Multipole field Genetic algorithm Magnetic design

The Completeness of Accreting Neutron Star Binary Candidates from the Chinese Space Station Telescope

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Research in Astronomy and Astrophysics 2024年第9期24卷 28-36页

作者： Hao shen shun-Yi Lan Xiang-Cun Meng Yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China International Centre of Supernovae Yunnan Key LaboratoryKunming 650216China

A neutron star(NS)has many extreme physical conditions,and one may obtain some important information about an NS via accreting neutron star binary(ANSB)*** upcoming Chinese Space Station Telescope(CSST)provides an opportunity to search for a large sample of ANSB *** goal is to check the completeness of the potential ANSB samples from CSST *** this paper,we generate some ANSBs and normal binaries under the CSST photometric system by binary evolution and binary population synthesis method and use a machine learning method to train a classification *** the Precision(94.56%)of our machine learning model is as high as before study,the Recall is only about 63.29%.The Precision/Recall is mainly determined by the mass transfer rate between the NSs and their *** addition,we also find that the completeness of ANSB samples from CSST photometric data by the machine learning method also depends on the companion mass and the age of the *** candidates with a low initial mass companion star(0.1 M_(⊙)to 1 M_(⊙))have a relatively high Precision(94.94%)and high Recall(86.32%),whereas ANSB candidates with a higher initial mass companion star(1.1 M_(⊙)to 3 M_(⊙))have similar Precision(93.88%)and quite low Recall(42.67%).Our results indicate that although the machine learning method may obtain a relatively pure sample of ANSBs,a completeness correction is necessary for one to obtain a complete sample.

关键词： stars:neutron X-rays:binaries methods:analytical

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分辨率为1pm的波长监测新方法

物理学报 2006年第9期55卷 4709-4712页

作者：冯耀军曹庄琪陈麟沈启舜上海交通大学物理系上海200240

在亚毫米尺度金属包覆波导研究基础上,提出了一种波长监测的新方法.实验采用自由空间耦合技术,激发了波导中对波长变化十分灵敏的超高阶导模,并以此为探针,实现了1pm波长漂移的监测.

关键词：波长监测金属包覆波导超高阶导模

Recursive Filtering for Stochastic Systems With Filter-and-Forward Successive Relays

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1202-1212页

作者： Hailong Tan Bo shen qi Li Hongjian Liu School of Mathematics-Physics and Finance Anhui Polytechnic UniversityWuhu 241000China Anhui Future Technology Research Institute Anhui Polytechnic UniversityWuhu 241000China College of Information Science and Technology Donghua UniversityShanghai 201620China Engineering Research Center of Digitalized Textile and Fashion Technology Ministry of EducationShanghai 201620China School of Information Science and Engineering Hangzhou Normal UniversityHangzhou 311121China

In this paper,the recursive filtering problem is considered for stochastic systems over filter-and-forward successive relay(FFSR)*** FFSR is located between the sensor and the remote filter to forward the *** the successive relay,two cooperative relay nodes are adopted to forward the signals alternatively,thereby existing switching characteristics and inter-relay interferences(IRI).Since the filter-and-forward scheme is employed,the signal received by the relay is retransmitted after it passes through a linear *** objective of the paper is to concurrently design optimal recursive filters for FFSR and stochastic systems against switching characteristics and IRI of ***,a uniform measurement model is proposed by analyzing the transmission mechanism of ***,novel filter structures with switching parameters are constructed for both FFSR and stochastic *** the help of the inductive method,filtering error covariances are presented in the form of coupled difference ***,the desired filter gain matrices are further obtained by minimizing the trace of filtering error ***,the stability performance of the filtering algorithm is analyzed where the uniform bound is guaranteed on the filtering error ***,the effectiveness of the proposed filtering method over FFSR is verified by a three-order resistance-inductance-capacitance circuit system.

关键词： filtering successive stochastic

Improved Double Deep Q Network-Based Task Scheduling Algorithm in Edge Computing for Makespan Optimization

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Tsinghua Science and Technology 2024年第3期29卷 806-817页

作者： Lei Zeng qi Liu Shigen shen Xiaodong Liu School of Computer Science Nanjing University of Information Science and TechnologyNanjing 210044China School of Software Nanjing University of Information Science and TechnologyNanjing 210044China School of Information Engineering Huzhou UniversityHuzhou 313000China School of Computing Edinburgh Napier UniversityEdinburghEH105DTUK

Edge computing nodes undertake an increasing number of tasks with the rise of business ***,how to efficiently allocate large-scale and dynamic workloads to edge computing resources has become a critical *** study proposes an edge task scheduling approach based on an improved Double Deep Q Network(DQN),which is adopted to separate the calculations of target Q values and the selection of the action in two networks.A new reward function is designed,and a control unit is added to the experience replay unit of the *** management of experience data are also modified to fully utilize its value and improve learning *** learning agents usually learn from an ignorant state,which is *** such,this study proposes a novel particle swarm optimization algorithm with an improved fitness function,which can generate optimal solutions for task *** optimized solutions are provided for the agent to pre-train network parameters to obtain a better cognition *** proposed algorithm is compared with six other methods in simulation *** show that the proposed algorithm outperforms other benchmark methods regarding makespan.

关键词： edge computing task scheduling reinforcement learning makespan Double Deep Q Network(DQN)

Probabilistic prediction on three-dimensional roughness of discontinuity based on two-dimensional traces under rock tunnel excavation based on Bayesian theory

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Underground Space 2024年第1期14卷 338-356页

作者： qi Zhang Yuechao Pei Xiaojun Wang Xiaojun Li Yixin shen School of Civil Engineering Southeast UniversityNanjing 211189China Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

Three-dimensional(3D)roughness of discontinuity affects the quality of the rock mass,but 3D roughness is hard to be measured due to that the discontinuity is invisible in the ***-dimensional(2D)roughness can be calculated from the visible traces,but it is difficult to obtain enough quantity of the traces to directly derive 3D roughness during the tunnel *** this study,a new method using Bayesian theory is proposed to derive 3D roughness from the low quantity of 2D roughness *** more accurately calculating 3D roughness,a new regression formula of 2D roughness is established firstly based on wavelet *** new JRC3D prediction model based on Bayesian theory is then developed,and Markov chain Monte Carlo(MCMC)sampling is adopted to process JRC3D prediction *** discontinuity sample collected from the literature is used to verify the proposed *** groups with the sampling size of 2,3,4,and 5 of each group are randomly sampled from JRC2D values of 170 profiles of the discontinuity,*** research results indicate that 100%,90%,85%,and 60%predicting JRC3D of the sample groups corresponding to the sampling size of 5,4,3,and 2 fall into the tolerance interval[JRC_(true)–1,JRC_(true)+1].It is validated that the sampling size of 5 is enough for predicting *** sensitivities of sampling results are then analyzed on the influencing factors,which are the correlation function,the prior distribution,and the prior *** discontinuity across the excavation face at ZK78+67.5 of Daxiagu tunnel is taken as the tunnel engineering application,and the results further verify that the predicting JRC3D with the sampling size of 5 is generally in good agreement with JRC3D true values.

关键词： Rock discontinuity Joint roughness coefficient Tunnel excavation Bayesian theory Markov chain Monte Carlo sampling