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An Encoder with Speed over 40Gbps for RC LDPC Codes with Rates Up to 0.96

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Chinese Journal of Electronics 2016年第5期25卷 921-927页

作者： HE Zhiyong ZHAO Qiang xu hushan CUI Wenjuan LUO Yuxi Institute of Modern Physics Chinese Academy of Sciences

We propose a class of Rate-compatible(RC) Low-density parity-check(LDPC) codes with a very wide range of code rates. To widen the range of rates, we have developed an optimal transmission scheme to push the upper bound of code rates to 0.96. Characterized by a parity check matrix in a dual-diagonal form, the proposed RC LDPC code can be encoded in linear time. Constructed from shifted identity sub-matrices, the proposed codes are particularly well-suited for the high-speed implementation of parallel encoders. Furthermore, the encoder can be implemented efficiently with several left circular shifters and XOR gates. To maximize the encoding speed, we have proposed a q-parallel encoder architecture, where q is the size of each sub-matrix. The implementation results into Field programmable gate array(FPGA) devices indicate that a72-parallel encoder for the proposed RC LDPC code with a code rate from 0.5 to 0.96 is capable of reaching a speed of 42 Gigabits per second(Gbps) using a clock frequency of 300 MHz.

关键词： Low-density parity-check codes(LDPC) High-speed encoder Field programmable gate array(FPGA) implementation

Speed of the internal pellet target in CSRm

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Science China(Physics,Mechanics & Astronomy) 2009年第7期52卷 1047-1052页

作者： LI ZhanKui RONG XinJuan xu hushan ZHANG xueYing Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China Graduate University of Chinese Academy of Sciences Beijing 100049China

Pellet target is one of the main candidate targets in CSRm (cooler storage ring’s main ring) for hadron physics studies. Pellet speed is an important physical parameter for the target. Larger pellet speed could shorten the interacting time interval between the pellet and the cyclotron beam, and thus results in a small temperature variation for the pellet. This could make the pellet facility work in a stable condition. A fluid dynamic simulation was carried out for the pellet speed, and it was found that the maximum speed for the target pellet may be restricted to about 100 m/s even if all working parameters were set to their optimal values.

关键词： internal target pellet target pellet speed capillary fluid dynamics

Cluster dynamics modeling of niobium and titanium carbide precipitates inα-Fe andγ-Fe

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Chinese Physics B 2022年第2期31卷 509-515页

作者： Nadezda Korepanova Long Gu Mihai Dima hushan xu Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 101408China Institute for Physics and Nuclear Engineering Bucharest 077125Romania School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China Paul Scherrer Institute Villigen 5232Switzerland

Kinetic behaviors of niobium and titanium carbide precipitates in iron are simulated with cluster *** simulations,carried out in austenite and ferrite for niobium carbides,and in austenite for titanium carbide,are analyzed for dependences on temperature,solute concentration,and initial cluster *** results are presented for different temperatures and solute concentrations,compared to experimental data *** show little impact of initial cluster distribution beyond a certain relaxation time and that highly dilute alloys with monomers only present a significantly different behavior from denser alloys or ones with different initial cluster distributions.

关键词： cluster dynamics precipitates precipitation kinetics carbides

The stripper design and test at HIRFL-CSR

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Nuclear Science and Techniques 2010年第4期21卷 237-240页

作者： ZHANG Hongbin XIAO Guoqing YUAN Youjin xu hushan LI Zhankui LU Ziwei MAO Ruishi ZHAO Tiecheng Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China

Charge stripping is employed to produce multi-charged ions for injecting the cooling storage *** penetrating through the carbon foil,the widened distribution of ion charge states poses a limit to the ion ***,the carbon foil plays a key role in the charge stripping *** this paper,four strippers for Heavy Ion Research Facility at Lanzhou(HIRFL) and Cooling Storage Ring(CSR) are *** charge state distribution of the stripped ions is measured and the stripping efficiency of the foils is *** experimental results are consistent with the theoretical values.

关键词：兰州重离子加速器 CSR 塔设计多电荷离子重离子研究装置冷却储存环电荷态分布测试

Mass Dependence of Cross Section Fluctuation in Dissipative Reaction ^(19)F+^(51)V

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Chinese Physics Letters 1995年第11期12卷 661-664页

作者： LU Jun WANG Qi xu hushan LI Songlin ZHU Yongtai YIN xu FAN Enjie ZHANG Yuhu LI Zhichang ZHAO Kui LU Xiuqin HU Xiaoqing Institute of Modern Physics Academia SinicaLanzhou 730000 China Institute of Atomic Energy Beijing 102413 Institute of High Energy Phxsics Academia SinicaBeijing 100039

Excitation functions for projectile-like fragments from ^(19)F+^(51)V reaction have been measured at 102.25 to 109.50MeV in 250keV steps.A TOF+(ΔE-E)telescope atθ_(L)=21.7°is used to identify atomic number Z and mass number A of ejectiles *** of the dissipative cross section for a series of isotopes are *** coherence energy widths are extracted by generalized statistical fluctuation analysis and the dependence on mass number and on N/Z values are observed for the first time.

关键词： steps dissipative

Interaction Time Study of the Dissipative Process in the Reaction ^(19)F+^(45)Sc

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Chinese Physics Letters 1993年第11期10卷 656-659页

作者： WANG Qi LI Songlin LU Jun xu hushan YIN xu FAN Enjie GUO Zhongyan ZHU Yongtai XIE Yuanxiang LI Zhichang LU Xiuqin HU Xiaoqing Institute of Modern Physics Academia SinicaLanzhou 730000 China Institute of Atomic Energy Academia SinicaBeijing 102413 Institute of High Energy Physics Beijing 100039

Excitation functions have been measured for the dissipative products of 4≤Z≤12 in ^(19)F+^(45)Sc reaction from 102 to ^(108)MeV by a step of 300keV at θl=42°.The energy coherence widths have been extracted and the dinuclear system lifetimes of the order of 10^(-21 ) s have been deduced by analysing the cross section Auctuations.

关键词： dinuclear dissipative

Pellet Target- a novel internal target at CSRm

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IMP & HIRFL Annual Report 2004年 196-197页

作者： Li Zhankui and xu hushan

The internal targets used in the storage ring are quite promising targets due to the well defined reaction vertex, low background and undisturbed reaction products. Light-isotope targets, such as hydrogen and deuterium, are the most favorite candidates for hadron physics study. For physical experiments, the figure of merit is usually the luminosity, and it is found that the frozen micro-spheres (called pellets) could provide a high luminosity which is comparable to that of an external target, whereas the conventional gas targets can not reach this criterion because of the heavy gas load in the reaction chamber. A global detector with nearly '4 configuration can be arranged around the pellet target. In the near future, a pellet target facility with global detectors is foreseen at CSRm in Lanzhou.

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An ellipsoidal time detector with PMT readout

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Nuclear Science and Techniques 2009年第4期20卷 248-250页

作者： LI Jiaxing LIU Pingping WANG Jiansong XIAO Guoqing GUO Zhongyan HU Zhengguo MAO Ruishi SUN Zhiyu xu hushan ZHAN Wenlong School of Physical Science and Technology Southwest University Chongqing 400715 China Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China

In this paper we present a timing detector which has low detection threshold and is *** photons induced by radioactive beam ions passing through a thin plastic-scintillator foil BC422,emit from the foil center corresponding to one focal point of an aluminum ellipsoidal mirror and are reflected to another focus point at which the cathode of a photomultiplier tube locates.A time resolution of about 115 ps can be achieved for1 2N of 58.5 MeV/u and 130 ps for1 7B of 43.7 MeV/*** counting rate up to 10 8packets per second(pps) is allowed.

关键词： PMT 光量子放射性原子核物理学

Measurement of the Fluctuations in DIC Excitation Function

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Chinese journal of nuclear physics 1995年第3期17卷 254-259页

作者： xu, hushan Wang, Qi Lu, Jun Li, Songlin Fan, Enjie Li, Zhichang Zhao, Kui Lu, Xiuqin Hu, Xiaoqing Inst of Modern Physics Chinese Acad of Sciences Lanzhou China

An experimental setup successfuUy used for measuring the fluctuations in deep inelastic colli-sion(DIC)excitation functions is *** the preliminary results of the experiment,the dependenceof the coherence energy widths... 详细信息

关键词： Fluctuation DIC excitation function Element and Isotope identification Coherence energy width Interaction time