检索结果-南通市图书馆

Progress of Lyman-alpha-based beam emission spectroscopy(Ly BES)diagnostic on the HL-2. tokamak

在线全文

学校读者我要写书评

暂无评论

Plasma science and Technology 2024年第3期26卷 118-125页

作者：周艺轩余羿许敏柯锐聂林徐皓赵光义刘灏袁子豪肖晨雨李继全肖池阶 the HL-2. Team Southwestern Institute of Physics Chengdu 610041People's Republic of China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082People's Republic of China State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871People's Republic of China

An edge Lyman-alpha-based beam emission spectroscopy(LyBES)diagnostic,using a heating NBI(neutral beam injection)system,is currently under development on the HL-2. *** 2.-channel edge LyBES,which is intended to measure the density fluctuation in plasma edge(from R=1960 mm to R=2.2. mm)with an improved spatial resolution of 3.3 mm,is a complement to the existing conventional beam emission spectroscopy(BES)*** this article,we introduce the progress of LyBES diagnostic,including the collection optics,the monochromator,and the detector *** reflectance of the collection mirrors is measured to be~82.at 12. nm,and the aberration geometrical radius of the collection optics is tested to be~150μm in the aimed *** linear dispersion of the LyBES monochromator is designed to be~0.09 nm mm^(-1).The bandwidth of the detector system with the 5×10^(7)V A^(-1)preamplifier gain is measured to be~2.0 kHz,and the peak-to-peak noise of the detector system is tested to be~16 *** finalized design,components development and testing of the LyBES diagnostic have been completed at present,and an overall performance of the LyBES diagnostic is to be confirmed in the next HL-2. campaign.

关键词： density fluctuation Ly BES BES vacuum ultraviolet

CONDITIONS FOR UNIFORMLY NON-CONFOUNDING OF CAUSAL DISTRIBUTION EFFECTS OVER MULTIPLE COVARIATES

在线全文

学校读者我要写书评

暂无评论

Journal of Systems science & Complexity 2010年第4期23卷 796-803页

作者： Xueli WANG school of science,Beijing {2. of posts and telecommunications,Beijing 100876,china. school of science Beijing University of Posts and Telecommunications Beijing China

Causation is a distinct concept from association and more important than association inepidemiologic *** paper proposes the concept of uniform non-confounding for causal distributioneffects over multiple covariates,and gives the sufficient conditions for uniform non-confoundingover a covariate set C including confounders or non-confounders,and also shows the conditions forconditionally non-confounding in the *** these conditions can be tested by observeddata.

关键词： Causal distribution effect confounding covariates uniform non-confounding

On the construction of multi-output Boolean functions with optimal algebraic immunity

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2012年第7期55卷 1617-1623页

作者： ZHANG Jie 1,2.,SONG ShouChao 1 ,DU Jiao 2.3 & WEN QiaoYan 2.1 school of science,Beijing {2. of posts and telecommunications,Beijing 100876,china 2.State Key Laboratory of Networking and Switching Technology,Beijing {2. of posts and telecommunications,Beijing 100876,china 3 Department of Mathematics,Xinxiang {2.,Xinxiang 453003,china school of science Beijing University of Posts and Telecommunications Beijing China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing China Department of Mathematics Xinxiang University Xinxiang China

In this paper,we show a construction of multi-output Boolean functions with optimal algebraic ***,the relationship between the algebraic immunity of a multi-output Boolean function and those of its component functions is *** show that all the component functions,together with their nonzero linear combination,of the multi-output Boolean functions achieved by this construction have optimal algebraic immunity simultaneously.

关键词： algebraic immunity Boolean functions algebraic attacks annihilators

On the Symmetry Classes of Functions

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Wuhan university Journal of Natural sciences 2005年第5期10卷 813-816页

作者： ZHU Ping~1,2. FAN Yun~3 1. school of Mathematics and Statistics, Wuhan university, Wuhan 430072. Hubei,{2. 2. school of science, Beijing university of posts and telecommunications, Beijing 100876,{2. 3. school of Mathematics and Statistics, Huazhong Normal university, Wuhan 430079, Hubei,{2. school of Mathematics and Statistics Wuhan University Wuhan Hubei China school of science Beijing University of Posts and Telecommunications Beijing China school of Mathematics and Statistics Huazhong Normal University Wuhan Hubei China

Let R be an integral domain of characteristic zero such that the corresponding group rings have block decompositions. We first prove that the submodule consisting of all the R-valued ξi-symmetric functions of several variables is a symmetry class, where ξi is any block character. Then we present a relationship among certain operators introduced for block character. Then we present a relationship among certain operators introduced for block characters. As a consequence, we obtain a decomposition of an arbitrary R-valued function of several variables. Finally, we describe the symmetry property of such summands and determine all the symmetry classes.

关键词： symmetry class strict symmetry class blockcharacter ξi-symmetric function block idempotent

The tri-band high spectral resolution spectrometer with gratings in tandem for the charge-exchange recombination spectroscopy diagnostic system on HL-2. tokamak

在线全文

学校读者我要写书评

暂无评论

Plasma science and Technology 2024年第6期26卷 103-110页

作者：刘亮余德良马倩何小斐 Maarten DE BOCK Manfred von HELLERMANN Michael WALSH 陈文锦何小雪魏彦玲张能李栋魏会领 the HL-2. Team Southwestern Institute of Physics Chengdu 610041People’s Republic of China College of Physics and Optoelectronic Technology Baoji University of Arts and SciencesBaoji 721000People’s Republic of China ITER Organization Route de Vinon-sur-VerdonCS 90046St.Paul Lez Durance Cedex 13067France Fusion Spectroscopy Markgraf-Albrecht Str.14Berlin 10711Germany

Charge-exchange(CX) recombination spectroscopy is a powerful tool monitoring ion temperature and plasma rotation with good temporal and spatial resolutions. A compact, new design for a high-throughput, tri-band high spectral resolution spectrometer has been developed for the charge-exchange recombination spectroscopy measurement on the HL-2. tokamak. The simultaneous measurements of He II(468.57 nm), C VI(52..1 nm), and Dα(656.1 nm accompanied by beam emission spectra) with an acquisition frequency up to 400 Hz are achieved by vertically binning the spectrum from each fiber in experiments. Initial results indicate that the system can provide radial profiles of not only ion temperature and rotation velocity,but also concentration of carbon. For the case of helium, the measurements for the ion temperature and rotation velocity are straightforward but the apparent concentration associated with the observed CX intensity is obviously too high. Modeling of the active He II CX feature including plume contributions needs to be carried out to extract the true helium *** spectrometer could become a prototype for the ITER charge-exchange recombination spectroscopy diagnostic and the pilot experiments, as presented here, demonstrate the possibility of impurity concentrations measurements based on the combined measurement of local beam emission and charge-exchange recombination spectroscopy spectra.

关键词： CXRS ion temperature plasma rotation impurity concentration

Reverse reconciliation for continuous variable quantum key distribution

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2010年第1期53卷 100-105页

作者： LU ZhiXin 1,2., YU Li 1,2., LI Kang 1,2., LIU BingCan 1,2.3 , LIN JianGui 1,2., JIAO RongZhen 1,2.& YANG BoJun 1,2. school of science, Beijing {2. of posts and telecommunications, Beijing 100876, china 2.Key Laboratory of Information Photonics and Optical Communication, Ministry of Education, Beijing {2. of posts and telecommunications, Beijing 100876, china 3 Department of Fundamental Courses, Academy of Armored Force Engineering, Beijing 100072. china school of science Beijing University of Posts and Telecommunications Beijing China Key Laboratory of Information Photonics and Optical Communication Ministry of Education Beijing University of Posts and Telecommunications Beijing China Department of Fundamental Courses Academy of Armored Force Engineering Beijing China

An efficient and practical post-processing technique based on reverse reconciliation for continuous variable quantum key distribution is proposed and simulated with low-density parity check (LDPC) codes. MultiLevel Coding/ MultiStage Decoding, which fully utilizes optimization technique such as vector quantization and iterative decoding and the optimal channel coding most close to the Shannon limit, was used to realize efficient reverse reconciliation algorithm. Simulation results showed that the proposed method can improve the secure key distribution rate to 2.2.kb/s and the coding efficiency to 0.89 over 2. km in single-mode optical fiber. Moreover, there still is room for much improvement.

关键词： quantum communication key distribution reverses reconciliation low-density parity check codes

Effects of impurity on the entanglement of the three-qubit Heisenberg XXX spin chain

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2007年第2期50卷 208-214页

作者： HU MingLiang1 & TIAN DongPing2.1 school of science,Xi’an Jiaotong {2.,Xi’an 710049,china 2.Xi’an Institute of posts and telecommunications,Xi’an 710061,china school of science Xi’an Jiaotong University Xi’an China Xi’an Institute of posts and telecommunications Xi’an China

We investigate the entanglement of the three-qubit Heisenberg XXX chain in the presence of impurity and obtain the analytical expressions of the concurrence C. It is found that for impurity entanglement, C appears only when J 1 > J for J > 0, and J 1 > 0 for J 0 and ?2. < J 1 < J, and initially increases with the increase of J 1 and arrives at the maximum value C max = (e4J/T ?3)/(e4J/T + 3) before it decays to zero gradually, so is the critical temperature T c with, however, the maximum value T cmax = 4J/In3.

关键词： Heisenberg XXX chain impurity thermal entanglement

Neighborhood-following algorithms for linear programming

在线全文

学校读者我要写书评

暂无评论

science china Mathematics 2004年第6期47卷 812-820页

作者： Al Wenbaoschool of science, Beijing {2. of posts and telecommunications, Beijing 100876, china school of science Beijing University of Posts and Telecommunications Beijing China

In this paper, we present neighborhood-following algorithms for linear programming. When the neighborhood is a wide neighborhood, our algorithms are wide neighborhood primal-dual interior point algorithms. If the neighborhood degenerates into the central path, our algorithms also degenerate into path-following algorithms. We prove that our algorithms maintain the O9√nL) -iteration complexity still, while the classical wide neighborhood primal-dual interior point algorithms have only the O(nL-iteration complexity. We also proved that the algorithms are quadratic convergence if the optimal vertex is nondegenerate. Finally, we show some computational results of our algorithms.

关键词： linear programming primal-dual interior point methods wide neighborhood methods quadratic convergence

EXIT analysis of M-algorithm based MIMO detectors and LDPC code design optimization

在线全文

学校读者我要写书评

暂无评论

science in china(Series F) 2009年第12期52卷 2248-2258页

作者： YOU MingHou1,2. TAO XiaoFeng1,2. CUI QiMei1,2.& ZHANG Ping1,2.1 Wireless Technology Innovation Institute, Beijing university of posts and {2., Beijing 100876, china 2.Key Laboratory of Universal Wireless Communications, (Beijing university of posts and {2.), Ministry of Education, Beijing 100876, china Wireless Technology Innovation Institute Beijing University of Posts and Telecommunications Beijing China Key Laboratory of Universal Wireless Communications (Beijing University of Posts and Telecommunications) Ministry of Education Beijing China

This paper investigates joint design and optimization of both low density parity check （LDPC） codes and M-algorithm based detectors including iterative tree search （ITS） and soft-output M-algorithm （SOMA） in multiple-input multiple-output （MIMO） systems via the tool of extrinsic information transfer （EXIT） charts. First, we present EXIT analysis for ITS and SOMA. We indicate that the extrinsic information transfer curves of ITS obtained by Monte Carlo simulations based on output log-likelihood rations are not true EXIT curves, and the explanation for such a phenomenon is given, while for SOMA, the true EXIT curves can be computed, enabling the code design. Then, we propose a new design rule and method for LDPC code degree profile optimization in MIMO systems. The algorithm can make the EXIT curves of the inner decoder and outer decoder match each other properly, and can easily attain the desired code with the target rate. Also, it can transform the optimization problem into a linear one, which is computationally simple. The significance of the proposed optimization approach is validated by the simulation results that the optimized codes perform much better than standard non-optimized ones when used together with SOMA detector.

关键词： MIMO systems iterative receiver LDPC codes code optimization EXIT charts M-algorithm