检索结果-南通市图书馆

Design and realization of vacuum control and interlock system for SESRI project

在线全文

学校读者我要写书评

暂无评论

Radiation Detection Technology and Methods 2022年第4期6卷 502-507页

作者： Zhang Jianchuan Min Yue Li Lili Ma Tao Zhou Detai Yin Jia Wang Yanyu Institute of Modern Physics Chinese Academy of SciencesLanzhouChina

Background Vacuum control and interlock system plays an important role in maintaining the vacuum condition for the normal operation of SESRI heavy ion accelerator.Vacuum failure of beam line at any position will cause beam loss,experimental failure,and even serious consequences of accelerator shutdown.Methods This control system is designed and realized based on EPICS structure and PLC controller to realize the control and interlocking function of all kinds of vacuum equipment and ensure the operation and safety of the equipment.PLC level interlock and contact-based hardware interlock methods are used to realize both stability andﬂexibility.Results After a period of test running and actual operation,it is proved that this vacuum control and interlock system shows good stability,reliability andﬂexibility.Conclusion The vacuum control and interlock system in this paper realizes the design requirements of vacuum degree display,valve operability,correct and adjustable interlocking for the SESRI heavy ion accelerator vacuum system.

关键词： Vacuum control Interlock EPICS PLC

Enhancement of Sensitivity by Initial Phase Matching in SU(1,1) Interferometers

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical physics 2019年第1期71卷 37-42页

作者：肖骁梁宏宾李国龙王晓光 Zhejiang Institute of Modern Physics Department of Physics Zhejiang University

We derive a general phase-matching condition(PMC) for enhancement of sensitivity in SU(1,1) interferometers. Under this condition, the quantum Fisher information(QFI) of two-mode SU(1,1) interferometry becomes maximal with respect to the relative phase of two modes, for the case of an arbitrary state in one input port and an even(odd) state in the other port, and the phase sensitivity is enhanced. We also find that optimal parameters can let the QFI in some areas achieve the Heisenberg limit for both pure and mixed initial states. As examples, we consider several input states: coherent and even coherent states, squeezed vacuum and even coherent states, squeezed thermal and even coherent states. Furthermore, in the realistic scenario of the photon loss channel, we investigate the effect of photon losses on QFI with numerical studies. We find the PMC remains unchanged and is not affected by the transmission coefficients for the above input states. Our results suggest that the PMC can exist in various kinds of interferometers and the phase-matching is robust to even strong photon losses.

关键词： quantum Fisher information SU(1,1) parameter estimation phase-matching condition

Microstructure of Hydrogen-Implanted Polycrystalline α-SiC after Annealing

在线全文

学校读者我要写书评

暂无评论

Chinese physics Letters 2018年第9期35卷 50-52页

作者：刘会平李锦钰李炳生 Institute of Modern Physics Chinese Academy of Sciences

Microstructural evolution in H-implanted polycrystalline a-SiC upon thermal annealing at temperature 1100℃ is studied. After annealing, the samples are examined via cross-sectional transmission electron microscopy （XTEM） analysis. H2 gas bubbles are formed during H implantation and some H2 molecules are released from the bubble to form cavities during thermal annealing. The distribution and size of the observed cavities are related to the implantation fluence. The results are compared to H implanted single crystal SiC and He implanted polycrystalline α-SiC. The possible reasons are discussed.

关键词： Microstructure of Hydrogen-Implanted Polycrystalline SiC after Annealing

Photo-and electro-production of narrow exotic states:From light quarks to charm and up to bottom

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2023年第4期18卷 71-94页

作者： Xu Cao Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000 China University of Chinese Academy of Sciences Beijing 100049China Research Center for Hadron and CSR physics Lanzhou University and Institute of Modern Physics of CASLanzhou 730000China

Accessing a full image of the inner content of hadrons represents a central endeavour of modern particle physics,with the main scientific motivation to investigate the strong interaction binding the visible matter.On the one hand,the structure of known exotic candidates is a fundamental open issue addressed widely by scientists.On the other hand,looking for new states of exotic nature is a central component for theoretical and experimental efforts from electron-positron machine and electron accelerator with fixed target to heavy ion and electron-ion colliders.In this article we present a succinct short overview of the attempt to search for exotic narrow N∗and Z states containing light quarks only or also charm,and its connotation for bottom regions(the latter two are also known as Pc(Zc)and Pb(Zb)states,respectively in the literature).We address the effort of searching for exotic narrow N∗and Z states in light quark sector.We focus on recent progress in searching for signal of Pc and Zc states photoproduction and its implication into the Pb and Zb photoproduction and their decay properties.We also discuss future perspectives for the field in electron-ion colliders,a good place to disentangle the nature of some of these states and investigate some other enlightening topics including QCD trace anomaly and quarkonium-nucleon scattering length.

关键词： exotic states photo-and electro-production electron-ion colliders hadron

Lambda polarization at the Electron-ion collider in China

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2023年第10期34卷 117-125页

作者： Zhaohuizi Ji Xiao-Yan Zhao Ai-Qiang Guo Qing-Hua Xu Jin-Long Zhang institute of Frontier and Interdisciplinary Science Shandong UniversityQingdao 266237China Institute of Modern Physics of CAS Lanzhou 730000China Southern Center for Nuclear‑Science Theory(SCNT) Institute of Modern PhysicsChinese Academy of SciencesHuizhou 516000China

Lambda polarization can be measured through its self-analyzing weak decay, making it an ideal candidate for studying spin effects in high-energy scattering. In lepton-nucleon deep inelastic scattering(DIS), Lambda polarization measurements can probe polarized parton distribution functions(PDFs) and polarized fragmentation functions(FFs). One of the most promising facilities for high-energy nuclear physics research is the proposed Electron-ion collider in China(EicC). As a next-generation facility, EicC is set to advance our understanding of nuclear physics to new heights. In this article, we study the Lambda production in electron-proton collisions at the EicC energy, in particular the reconstruction of Lambda based on the performance of the designed EicC detector. In addition, taking spontaneous transverse polarization as an example, we provide a theoretical prediction with a statistical projection based on one month of EicC data, offering valuable insights into future research prospects.

关键词： Electron-ion collider in China Lambda polarization Polarizing fragmentation functions Nucleon structure

Calculation of microscopic nuclear level densities based on covariant density functional theory

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2023年第9期34卷 118-127页

作者： Kun-Peng Geng Peng-Xiang Du Jian Li Dong-Liang Fang College of physics Jilin UniversityChangchun 130012China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China

In this study,a microscopic method for calculating the nuclear level density(NLD)based on the covariant density functional theory(CDFT)is developed.The particle-hole state density is calculated by a combinatorial method using single-particle level schemes obtained from the CDFT,and the level densities are then obtained by considering collective effects such as vibration and rotation.Our results are compared with those of other NLD models,including phenomenological,microstatisti-cal and nonrelativistic Hartree–Fock–Bogoliubov combinatorial models.This comparison suggests that the general trends among these models are essentially the same,except for some deviations among the different NLD models.In addition,the NLDs obtained using the CDFT combinatorial method with normalization are compared with experimental data,including the observed cumulative number of levels at low excitation energies and the measured NLDs.The CDFT combinatorial method yields results that are in reasonable agreement with the existing experimental data.

关键词： Nuclear level density Covariant density functional theory Combinatorial method

强激光影响核同质异能态:物理机制与前景展望

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2022年第15期67卷 1526-1529页

作者：马志国符长波何万兵马余刚 Key Laboratory of Nuclear physics and Ion-beam Application(MoE) Institute of Modern PhysicsFudan UniversityShanghai 200433China

Over one hundred years have passed since the nuclear isomer was first introduced,in analogy with chemical isomers to describe long-lived excited nuclear states.In 1921,Otto Hahn discovered the first nuclear isomerPa.After that,step by step,it was realized that different types of nuclear isomers exist,including spin isomer,K isomer,seniority isomers,and"shape and fission"isomer[1,2].

关键词： states. isomers 同质异能态

The Deformation Analysis of the 3D Alignment Control Network Based on the Multiple Congruence Models

在线全文

学校读者我要写书评

暂无评论

Journal of Geodesy and Geoinformation Science 2023年第2期6卷 21-31页

作者： Xudong ZHANG Wenjun CHEN Xiaodong ZHANG Yajun ZHENG Bin ZHANG Shaoming WANG Jiandong YUAN Guozhen SUN Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China

In the construction and maintenance of particle accelerators,all the accelerator elements should be installed in the same coordinate system,only in this way could the devices in the actual world be consistent with the design drawings.However,with the occurrence of the movements of the reinforced concrete cover plates at short notice or building deformations in the long term,the control points upon the engineering structure will be displaced,and the fitness between the subnetwork and the global control network may be irresponsible.Therefore,it is necessary to evaluate the deformations of the 3D alignment control network.Different from the extant investigations,in this paper,to characterize the deformations of the control network,all of the congruent models between the points measured in different epochs have been identified,and the congruence model with the most control points is considered as the primary or fundamental model,the remaining models are recognized as the additional ones.Furthermore,the discrepancies between the primary S-transformation parameters and the additional S-transformation parameters can reflect the relative movements of the additional congruence models.Both the iterative GCT method and the iterative combinatorial theory are proposed to detect multiple congruence models in the control network.Considering the actual work of the alignment,it is essential to identify the competitive models in the monitoring network,which can provide us a hint that,even the fitness between the subnetwork and the global control network is good,there are still deformations which may be ignored.The numerical experiments show that the suggested approaches can describe the deformation of the 3D alignment control network roundly.

关键词： similarity transformation 3D alignment control network deformation analysis hypothesis testing iterative global congruence test iterative combinatorial theory

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

在线全文

学校读者我要写书评

暂无评论

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