检索结果-南通市图书馆

Study of weakly-bound odd-A nuclei with quasiparticle blocking

在线全文

学校读者我要写书评

暂无评论

Chinese physics C 2016年第2期40卷 19-24页

作者：熊雪宇裴俊琛张一怒朱怡 State Key laboratory of Nuclear physics and technology School of PhysicsPeking University

The coordinate-space Hartree-Fock-Bogoliubov（HFB） approach with quasiparticle blocking has been applied to study the odd-A weakly bound nuclei ^17,19B and ^37Mg,in which halo structures have been reported in *** Skyrme nuclear forces SLy4 and UNEDF1 have been adopted in our *** results with and without blocking have been compared to demonstrate the emergence of deformed halo structures due to blocking *** our calculations,^19B and ^37Mg have remarkable features of deformed halos.

关键词： deformed halo blocking effects weakly bound nuclei Hartree-Fock-Bogoliubov

Electrically and Optically Bistable Operation in an Integration of a 1310 nm DFB Laser and a Tunneling Diode

在线全文

学校读者我要写书评

暂无评论

Chinese physics Letters 2018年第4期35卷 38-41页

作者： Ya-Jie Li Jia-Qi Wang Lu Guo Guang-Can Chen Zhao-Song Li Hong-Yan Yu Xu-Liang Zhou Huo-Lei Wang Wei-Xi Chen Jiao-Qing Pan Key laboratory of Semiconductor Materials science Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 College of Materials science and Opto-Eleetronic technology University of Chinese Academy of Sciences Beijing 100049 Department of Applied physics and Materials science California Institute of Technology California 91125 USA State Key laboratory for Mesoscopic physics School of Physics Peking University Beijing 100871

We experimentally demonstrate an In P-based hybrid integration of a single-mode DFB laser emitting at around 1310 nm and a tunneling diode. The evident negative differential resistance regions are obtained in both electrical and optical output characteristics. The electrical and optical bistabilities controlled by the voltage through the tunneling diode are also measured. When the voltage changes between 1.46 V and 1.66 V, a 200-mV-wide hysteresis loop and an optical power ON/OFF ratio of 17 dB are obtained. A side-mode suppression ratio of the integrated device in the ON state is up to 43 dB. The tunneling diode can switch on/off the laser within a very small voltage range compared with that directly controlled by a voltage source.

关键词： DFB In Electrically and Optically Bistable Operation in an Integration of a 1310 nm DFB Laser and a Tunneling Diode

Implementation of encoder and decoder for LDPC codes based on FPGA

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2019年第4期30卷 642-650页

作者： CHENG Kun SHEN Qi LIAO Shengkai PENG Chengzhi Department of Modern physics University of Science and Technology of ChinaHefei 230026China Shanghai Branch National Laboratory for Physical Sciences at Microscale and Department of Modern PhysicsUniversity of Science and Technology of ChinaHefei 230026China Chinese Academy of sciences Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum physics University of Science and Technology of ChinaShanghai 201315China

This paper proposes a parallel cyclic shift structure of address decoder to realize a high-throughput encoding and decoding method for irregular-quasi-cyclic low-density parity-check(IR-QC-LDPC)codes,with a dual-diagonal parity structure.A normalized min-sum algorithm(NMSA)is employed for *** whole verification of the encoding and decoding algorithm is simulated with Matlab,and the code rates of 5/6 and 2/3 are selected respectively for the initial bit error ratio as 6%and 1.04%.Based on the results of simulation,multi-code rates are compatible with different basis *** the simulated algorithms of encoder and decoder are migrated and implemented on the field programmable gate array(FPGA).The 183.36 Mbps throughput of encoder and the average 27.85 Mbps decoding throughput with the initial bit error ratio 6%are realized based on FPGA.

关键词： low-density parity-check(LDPC) field programmable gate array(FPGA) normalized min-sum algorithm(NMSA).

Near-field properties of a shell nanocylinder pair with gain materials

在线全文

学校读者我要写书评

暂无评论

Chinese physics B 2012年第11期21卷 388-392页

作者：王乔吴世法王晓钢 MOE Key laboratory of Materials Modification by Beams School of Physics&Optoelectronic EngineeringDalian University of Technology State Key laboratory of Nuclear physics and technology School of PhysicsPeking University

We study the near-field response of a shell nanocylinder pair, with its core filled by gain materials, using a two- dimensional finite-difference time-domain method. It is shown that the gain materials in the core of the cylinder can compensate for the intrinsic absorption of the metal shell, leading to local-field enhancement in the gap of the active pair. A linear dependence is found between the field enhancement and the gain coefficient at resonance. The detailed physics is studied by calculating the electrical-field distribution of the shell pair filled with different gain materials. The influence of the gap width and the shell thickness on the interaction of two adjacent active shell cylinders is also investigated.

关键词： shell nanocylinder pair gain material local-field enhancement

Performance of a small AT-TPC prototype

在线全文

学校读者我要写书评

暂无评论

Nuclear science and Techniques 2018年第7期29卷 138-144页

作者： Jin-Yan Xu Qi-Te Li Yan-Lin Ye Jian Gao Jia-Xing Han Shi-Wei Bai Ka-Hou Ng School of physics and State Key laboratory of Nuclear physics and technology Peking University

A small prototype of an active-target time projection chamber detector based on the gas electron multiplier(GEM) readout technique was designed and *** calculations were performed to analyze the electric field distribution and optimize the *** particular,a guard ring installed above the GEM foil may play an important role in shaping the electric field in the gas vessel and improving the overall performance of the *** best results were obtained at a guard-ring voltage of-950 *** using a collimated a-particle source,an energy resolution of 3.6–4.0 ke V can be achieved for deposited energies of 18–21 keV,respectively.A position resolution of less 0.2 mm was observed along the electron drift direction,whereas the resolution in the readout plane was approximately 0.45 mm.A time resolution of less than 20 ns was *** using helium as the primary working gas as well as the target material,a t a elastic scattering events can be clearly imaged.

关键词：原型性能优化设计模拟计算工作气体宝石时间电子

Infrared radiation characteristics of a hypersonic vehicle under time-varying angles of attack

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2019年第4期32卷 861-874页

作者： Qinglin NIU Zhichao YUAN Biao CHEN Shikui DONG School of Energy science and Engineering Harbin Institute of Technology Key laboratory of Aerospace Thermophysics of Ministry of Industry and Information technology Harbin Institute of Technology Key laboratory of Chemical Laser Dalian Institute of Chemical Physics Chinese Academy of Sciences

Hypersonic vehicles emit strong infrared(IR) radiation signatures that can be treated as a detecting source for object identification and routine diagnosis. This paper is aimed at examining the intrinsic radiation characteristics of a Boost-Glide Vehicle(BGV) under the condition of various Angles of Attack(AOAs). A two-temperature model considering the thermal and chemical nonequilibrium effects is coupled with Navier-Stokes equations solved by the finite volume technique.A gas–solid conjunction heat transfer model is also added into the fluid solver to simulate the surface temperature of the vehicle. The radiative transfer equation is solved with Line of Sight(LOS)algorithm. The computational results for a Hypersonic technology Vehicle-2(HTV-2) type vehicle show that radiances of the vehicle are strongly dependent on the surface temperature. The presence of AOA results in the significant difference of the surface temperature. Infrared radiation characteristics are also changed in intensity and spectral band due to the AOA. Simulations are performed with two time-varying AOAs. Transient results indicate that the variation of AOA does have a great effect on the infrared radiance and is closely related to observation angle, spectral band, angle size,angular velocity and time history.

关键词： Angle of attack Fluid-thermal interaction HTV-2 Hypersonic vehicle IR radiation Surface temperature

Phase transitions in bismuth under rapid compression

在线全文

学校读者我要写书评

暂无评论

Chinese physics B 2019年第3期28卷 300-303页

作者： Dong-Liang Yang Jing Liu Chuan-Long Lin Qiu-Min Jing Yi Zhang Yu Gong Yan-Chun Li Xiao-Dong Li Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of Science Center for High Pressure science and technology Advanced Research National Key laboratory for Shock Wave and Detonation physics Institute of Fluid PhysicsChinese Academy of Engineering Physics

The structural phase transitions of bismuth under rapid compression has been investigated in a dynamic diamond anvil cell using time-resolved synchrotron x-ray diffraction. As the pressure increases, the transformations from phase I,to phase II, to phase III, and then to phase V have been observed under different compression rates at 300 K. Compared with static compression results, no new phase transition sequence appears under rapid compression at compression rate from 0.20 GPa/s to 183.8 GPa/s. However, during the process across the transition from phase III to phase V, the volume fraction of product phase as a function of pressure can be well fitted by a compression-rate-dependent sigmoidal *** resulting parameters indicate that the activation energy related to this phase transition, as well as the onset transition pressure, shows a compression-rate-dependent performance. A strong dependence of over-pressurization on compression rate occurs under rapid compression. A formula for over-pressure has been proposed, which can be used to quantify the over-pressurization.

关键词： bismuth high pressure rapid compression over-pressurization

Neutronics Analysis of Water-Cooled Ceramic Breeder Blanket for CFETR

在线全文

学校读者我要写书评

暂无评论

Plasma science and technology 2016年第7期18卷 775-780页

作者：祝庆军李佳刘松林 Institute of Plasma physics Chinese Academy of Sciences School of Nuclear science and technology University of Science and Technology of China

In order to investigate the nuclear response to the water-cooled ceramic breeder blanket models for CFETR, a detailed 3D neutronics model with 22.5° torus sector was developed based on the integrated geometry of CFETR, including heterogeneous WCCB blanket models, shield, divertor, vacuum vessel, toroidal and poloidal magnets, and ports. Using the Monte Carlo N-Particle Transport Code MCNP5 and IAEA Fusion Evaluated Nuclear Data Library FENDL2.1, the neutronics analyses were performed. The neutron wall loading, tritium breeding ratio, the nuclear heating, neutron-induced atomic displacement damage, and gas production were determined. The results indicate that the global TBR of no less than 1.2 will be a big challenge for the watercooled ceramic breeder blanket for CFETR.

关键词： fusion reactor WCCB blanket TBR nuclear heating

Second-order slip MHD flow and heat transfer of nanofluids with thermal radiation and chemical reaction

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2015年第9期36卷 1131-1146页

作者： Jing ZHU Liu ZHENG Liancun ZHENG Xinxin ZHANG School of Mathematica and physics University of Science and Technology Beijing School of Mechanical Engineering University of Science and Technology Beijing

The effects of the second-order velocity slip and temperature jump boundary conditions on the magnetohydrodynamic （MHD） flow and heat transfer in the presence of nanoparticle fractions are investigated. In the modeling of the water-based nanofluids containing Cu and A1203, the effects of the Brownian motion, thermophoresis, and thermal radiation are considered. The governing boundary layer equations are transformed into a system of nonlinear differential equations, and the analytical approximations of the solutions axe derived by the homotopy analysis method （HAM）. The reliability and efficiency of the HAM solutions are verified by the residual errors and the numerical results in the literature. Moreover, the effects of the physical factors on the flow and heat transfer are discussed graphically.

关键词： nanofluid velocity slip temperature jump homotopy analysis method(HAM) heat and mass transfer magnetohydrodynamic (MHD) flow