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A high-power and high-stability power supply design

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Radiation Detection Technology and Methods 2021年第2期5卷 307-313页

作者： p.liu B.Chen p.F.Wei Institute of High Energy physics Chinese Academy of SciencesBeijing 100049China

Objective BEpCII is a high-performance collider with a design energy of 2.1 GeV. In order to obtain more physical experimentsand synchrotron radiation applications, BEpCII decided to carry out energy upgrading to 2.5 GeV. Insufficient energyof special magnet power supplies in collision zone is a key factor restricting BEpCII’s operation under 2.5 GeV ***, three high-power and high-stability power supplies are designed for BEpCII energy *** The designed power supplies output part adopts high-frequency chopper modules parallel connected and adoptsdigital-analog hybrid control methods. The voltage loop regulator uses high-speed analog control, and current loop regulatoruses digital control which is based on *** The experimental data show that the output current stability of the developed power supplies is lower than50 ppm. The output current resolution is lower than 70 ppm. The developed power supplies can well meet the design requirementsof BEpCII energy upgrading.

关键词： BEpCII energy upgrading High-frequency chopper High stability Digital-analog hybrid control

Control Schemes for passive Teleoperation Systems over Wide Area Communication Networks with Time Varying Delay

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International Journal of Automation and computing 2014年第1期11卷 100-108页

作者： Shafiqul Islam Xiaoping p.liu Abdulmotaleb El Saddik Lakmal Seneviratne Jorge Dias School of Information Technology and Engineering University of Ottawa School of Engineering and Applied Sciences Harvard University Robotics and Mechanical Engineering Khalifa University of Science & Technology Department of Systems and Computer Engineering Carleton University Electrical Engineering New York University Division of Engineering Kings College London Robotics and Electrical and Computer Engineering Khalifa University of Science & Technology Institute of Systems and Robotics University of Coimbra

In this paper,the problem of time varying telecommunication delays in passive teleoperation systems is *** design comprises delayed position,velocity and position-velocity signals with the local position and velocity signals of the master and slave *** adaptive control terms are employed locally to cope with uncertain parameters associated with the gravity loading vector of the master and slave ***-Krasovskii function is employed for three methods to establish asymptotic tracking property of the closed loop teleoperation *** stability analysis is derived for both symmetrical and unsymmetrical time varying delays in the forward and backward communication channel that connects the local and remote ***,evaluation results are presented to illustrate the efectiveness of the proposed design for real-time applications.

关键词： Teleoperation telerobotics Lyapunov-Krasovskii functional time varying delay passive systems

Synergistic and non-specific nucleic acid production by T7 RNA polymerase and Bsu DNA polymerase catalyzed by single-stranded polynucleotides

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Synthetic and Systems Biotechnology 2018年第2期3卷 130-134页

作者： Nicholas J.Emery Sagardip Majumder Allen p.liu Department of Mechanical Engineering University of MichiganAnn ArborMIUnited States Cellular and Molecular Biology program University of MichiganAnn ArborMIUnited States Department of Biomedical Engineering University of MichiganAnn ArborMIUnited States Biophysics program University of MichiganAnn ArborMIUnited States Department of Biomedical Engineering Boston UniversityBostonMAUnited States.

point-of-care molecular diagnostic tests show great promise for providing accurate,timely results in lowinfrastructure healthcare settings and at *** design space for these tests is limited by a variety of possible background reactions,which often originate from relatively weak promiscuous activities of the enzymes used for nucleic acid *** this background signal is amplified alongside the signal of the intended biomarker,the dynamic range of the test can be severely ***,a detailed knowledge of potential side reactions arising from enzyme promiscuity can improve rational design of point-of-care molecular diagnostic *** this end,we report a previously unknown synergistic reaction between T7 RNA polymerase and Bsu DNA polymerase that produces nucleic acid in the presence of single-stranded DNA or *** reaction occurs in the absence of any previously reported substrates for either polymerases and compromises a theoretical microRNA amplification scheme utilizing these polymerases.

关键词： catalyzed utilizing rational

A Target Grabbing Strategy for Telerobot Based on Improved Stiffness Display Device

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IEEE/CAA Journal of Automatica Sinica 2017年第4期4卷 661-667页

作者： pengwen Xiong Xiaodong Zhu Aiguo Song Lingyan Hu Xiaoping p.liu Lihang Feng School of Information Engineering Nanchang University School of Instrumentation Science and Engineering Southeast University IEEE Department of Systems and Computer Engineering Carleton University Computer Integrated Surgical Systems and Technology Engineering Research Center(CISST ERC) Johns Hopkins University

Most target grabbing problems have been dealt with by computer vision system, however, computer vision method is not always enough when it comes to the precision contact grabbing problems during the teleoperation process, and need to be combined with the stiffness display to provide more effective information to the operator on the remote side. Therefore, in this paper a more portable stiffness display device with a small volume and extended function is developed based on our previous work. A new static load calibration of the improved stiffness display device is performed to detect its accuracy, and the relationship between the stiffness and the position is given. An effective target grabbing strategy is presented to help operator on the remote side to judge and control and the target is classified by multi-class SVM(supporter vector machine). The teleoperation system is established to test and verify the feasibility. A special experiment is designed and the results demonstrate that the improved stiffness display device could greatly help operator on the remote side control the telerobot to grab target and the target grabbing strategy is effective.

关键词： Multi-class SVM(supporter vector machine) teleoperation target grabbing stiffness display

Research on high bandwidth power supply

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Radiation Detection Technology and Methods 2022年第3期6卷 409-417页

作者： p.liu F.L.Long Y.Li Institute of High Energy physics Chinese Academy of SciencesBeijing 100049People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China

Background Fourth-generation photon sources like Free Electron Lasers(FEL)and Diffraction-Limited Storage Rings(DLSR)have high requirements for beam *** the case of DLSR sources,a set of high-performance fast orbit feedback system(FOFB)is needed to correct the beam orbit quickly and *** FOFB system has four key components,which is BpM,orbit feedback calculation,fast correction magnet and fast corrector power *** FOFB gives the correction command and controls the fast corrector power supply to drive the fast correction magnet to correct the beam quickly and *** corrector power supply has an important impact on the performance of *** corrector power supply needs to have high bandwidth and low output current *** The new GaN power device is used to solve the restriction of the high-speed *** switching frequency of the power supply is increased to 300 *** control system is designed to improve the bandwidth and optimize the output current *** modeling analysis of the key parts of the system is given and the simulation experiments are carried out with *** and conclusion The test results showed that bandwidth of the designed power supply is 20 *** step response time is 18us and output current ripple is lower than 1 mA.

关键词： photon source FOFB High bandwidth MATLAB GaN

Design of precision acquisition system for precision power supply of photon source

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Radiation Detection Technology and Methods 2021年第4期5卷 586-593页

作者： p.liu F.L.Long Y.Z.Du Institute of High Energy physics Chinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

purpose photon source has developed to the fourth *** requirements for beam stability and power supply output current stability have been greatly *** this paper,a precision acquisition system is designed for improving the stability for power supply output *** The acquisition system consists of two parts,the analog to digital converter(ADC)system and the temperature control *** composition and software simulation analysis are given in this *** A prototype is made and *** test results showed that the acquisition system has an effective resolution of 15.5 bits,signal-to-noise ratio(SNR)of 98 dB,and integral nonlinearity(INL)of 86 *** internal temperature stable range is±0.06℃.Conclusions The acquisition system can fully meet the requirements of the developed photon source.

关键词： photon source Beam stability High precision Digital temperature control SNR

Semiconducting single-walled carbon nanotubes synthesized by S-doping

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Nano-Micro Letters 2009年第1期1卷 9-13页

作者： Z.J.Li L.Wang Y.J.Su p.liu Y.F.Zhang National Key Laboratory of Nano/Micro Fabrication Technology Key Laboratory for Thin Film and Microfabrication of the Ministry of Education Research Institute of Micro/Nanometer Science & Technology Shanghai Jiaotong University

An approach was presented for synthesis of semiconducting single-walled carbon nanotubes(SWNTs) by sulfur(S) doping with the method of graphite arc discharge. Raman spectroscopy, UV-vis-NIR absorption spectroscopy and electronic properties measurements indicated the semconducting properties of the SWNTs samples. Simulant calculation indicated that S doping could induce convertion of metallic SWNTs into semiconducting ones. This strategy may pave a way for the direct synthesis of pure semiconducting SWNTs.

关键词： S-doping Single-wall Carbon nanotubes Semiconducting Arc discharge

Development of high-precision DC power supply prototype for HEpS-TF

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Radiation Detection Technology and Methods 2019年第2期3卷 1-7页

作者： X.L.Guo F.L.Long B.Chen p.liu University of Chinese Academy of Sciences Beijing 100049China Institute of High Energy physics Chinese Academy of SciencesBeijing 100049China Dongguan Neutron Science Center Dongguan 523803China

purpose This power supply prototype is developed for the quadrupole magnets in the storage ring of *** project requires a high current stability of these power supplies,in order to master the key technology of this type of power supply in advance,a prototype is made in the project of HEpS test *** Modularization is used in the prototype’s topology and a combination of digital and analog control is adopted in the closed-loop *** control loops are used to improve the output current’s *** order to improve the current stability,the key devices in the circuit are under thermostatical *** The acceptance test results for the NDRC are given in details,which show that all the parameters are better than the design *** After a lot of experiments and tests,all the parameters of this prototype passed the acceptance *** the results,the stability of this prototype achieved 5.2 ppm,the repeatability is 3.2 ppm,and the low-frequency voltage ripples are lower than the requirements of *** success of this prototype means that the requirements of power supplies in physical design can be met.

关键词： Stability High-precision DC power supply Repeatability Voltage ripple

EFFECT OF COLD WORKING ON THE AGING pROpERTIES OF Cu-Cr-Zr-Mg ALLOY BY ARTIFICIAL NEURAL NETWORK

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Acta Metallurgica Sinica(English Letters) 2004年第5期17卷 741-746页

作者： J.H.Su H.J.Li Q.M.Dong p.liu B.X.Kang B.H.Tian CollegeofMaterialsScienceandEngineering NorthwesternPolytechnicalUniversityXi＇an710072China GollegeofMaterialsScienceandEngineering HenanUniversityofScienceandTechnologyLuoyang471003China

A developmental research has been carried out to deal with the high performance of Cu-Cr-Zr-Mg lead frame alloy by artificial neural network (ANN). Using the cold working to assist in the aging hardening can improve the the hardness and electrical conductivity properties of Cu-Cr-Zr-Mg lead frame alloy. This paper studies the effect of different extent of cold working on the aging properties by a supervised ANN to model the non-linear relationship between processing parameters and the properties. The back-propagation (Bp) training algorithm is improved by Levenberg-Marquardt algorithm. A basic repository on the domain knowledge of cold worked aging processes is established via sufficient data mining by the network. The predicted values of the ANN coincide well with the tested data. So an important foundation has been laid for prediction and optimum controlling the rolling and aging properties of Cu-Cr-Zr-Mg alloy.

关键词： Cu-Cr-Zr-Mg alloy cold working aging artificial neural network (ANN)