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Conditioning of BPM pickup signals for operations of the Duke storage ring with a wide range of single-bunch current

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Chinese Physics C 2014年第10期38卷 82-91页

作者：徐卫李京祎黄森林 w.z.wu H.Hao P.wang Y.K.wu National Synchrotron Radiation Laboratory (NSRL) University of Science and Technology of China Dept.of Physics Duke University and FEL labTriangle Universities Nuclear LaboratoryDurhamNC 27708-0308USA Institute of Heavy Ion Physics Peking University

The Duke storage ring is a dedicated driver for the storage ring based oscillator free-electron lasers（FELs）, and the High Intensity Gamma-ray Source（HIGS）. It is operated with a beam current ranging from about1 mA to 100 mA per bunch for various operations and accelerator physics studies. High performance operations of the FEL and γ-ray source require a stable electron beam orbit, which has been realized by the global orbit feedback system. As a critical part of the orbit feedback system, the electron beam position monitors（BPMs） are required to be able to precisely measure the electron beam orbit in a wide range of the single-bunch current. However, the high peak voltage of the BPM pickups associated with high single-bunch current degrades the performance of the BPM electronics, and can potentially damage the BPM electronics. A signal conditioning method using low pass filters is developed to reduce the peak voltage to protect the BPM electronics, and to make the BPMs capable of working with a wide range of single-bunch current. Simulations and electron beam based tests are performed. The results show that the Duke storage ring BPM system is capable of providing precise orbit measurements to ensure highly stable FEL and HIGS operations.

关键词： beam position monitor signal conditioning closed orbit feedback storage ring FEL

VOLUMETRIC MASS TRANSFER COEFFICIENT BETwEEN SLAG AND METAL IN COMBINED BLOwING CONVERTER

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Acta Metallurgica Sinica(English Letters) 2005年第2期18卷 91-95页

作者： z.H.wu z.S.zou w.wu SchoolofMaterialsandMetallurgy NortheasternUniversityShenyang110004China CentralIron＆SteelResearchInstitute Beijing100081China

The effects of operation parameters of combined blowing converter on the volumetric mass transfer coefficient between slag and steel are studied with a cold model with water simulating steel, oil simulating slag and benzoic acid as the transferred substance between water and oil. The results show that, with lance level of 2.1m and the top blowing rate of 25000Nm3/h, the volumetric mass transfer coefficient changes most significantly when the bottom blowing rate ranges from 384 to 540Nm3/h. The volumetric mass transfer coefficient reaches its maximum when the lance level is 2.1m, the top blowing rates is 30000Nm3/h, and the bottom blowing rate is 384Nm3/h with tuyeres located symmetrically at 0.66D of the converter bottom.

关键词： combined blowing converter cold modeling volumetric mass transfer coefficient operational parameter

Probing the Bardeen-Kiselev black hole with the cosmological constant caused by Einstein equations coupled with nonlinear electrodynamics using quasinormal modes and greybody bounds

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Communications in Theoretical Physics 2024年第6期76卷 102-119页

作者： S R wu B Q wang z w Long College of Physics Guizhou UniversityGuiyang 550025China College Pharmacy Guizhou University of Traditional Chinese MedicineGuiyang 550025China

In this work,we investigate a static and spherically symmetric Bardeen-Kiselev black hole(BH)with the cosmological constant,which is a solution of the Einstein-non-linear Maxwell field *** compute the quasinormal frequencies for the Bardeen-Kiselev BH with the cosmological constant due to electromagnetic and gravitational *** varying the BH parameters,we discuss the behavior of both real and imaginary parts of the BH quasinormal frequencies and compare these frequencies with the Reissner-Nordström-de Sitter BH surrounded by quintessence(RN-dSQ).Interestingly,it is shown that the responses of the Bardeen-Kiselev BH with the cosmological constant and the RN-dSQ under electromagnetic perturbations are different when the charge parameter q,the state parameter w and the normalization factor c are varied;however,for the gravitational perturbations,the responses of the Bardeen-Kiselev BH with the cosmological constant and the RN-dSQ are different only when the charge parameter q is ***,compared with the gravitational perturbations,the electromagnetic perturbations can be used to understand nonlinear and linear electromagnetic fields in curved spacetime *** interesting observation is that,due to the presence of Kiselev quintessence,the electromagnetic perturbations around the Bardeen-Kiselev BH with the cosmological constant damps faster and oscillates slowly;for the gravitational perturbations,the quasinormal mode decays slowly and oscillates *** also study the reflection and transmission coefficients along with the absorption cross section in the Bardeen-Kiselev BH with the cosmological constant;it is shown that the transmission coefficients will increase due to the presence of Kiselev quintessence.

关键词： quasinormal modes greybody factors Bardeen-Kiselev black hole with cosmological constant

The Novel Mechanical Property of Tongue of a woodpecker

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Journal of Bionic Engineering 2009年第3期6卷 214-218页

作者： P zhou X Q Kong C w wu z Chen National Key Laboratory for Structural Analysis of Industrial Equipment Dalian University of Technology Department of Civil and Environmental Engineering University of Missouri

Biomaterials such as bone,teeth,nacre and silk are known to have superior mechanical properties due to their specific nanocomposite *** we report that the woodpecker's tongue exhibits a novel strength and flexibility due to its special composite micro/*** tongue consists of a flexible cartilage-and-bone skeleton covered with a thin layer tissue of high strength and *** the interface between the cartilage-and-bone skeleton and the tissue layer,there is a hierarchical fiber-typed *** is this special design of the tongue that makes the woodpeckers efficient in catching the insects inside *** special micro/nanostructures of the woodpecker's tongue show us a potential method to enhance the interfacial connection between soft and hard material layers for bio-inspired composite system designs.

关键词： woodpeckcr hyoid cartllage multilevel structure tensile strength

A new model for the expansion tube considering the stress coupling:Theory,experiments and simulations

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Defence Technology（防务技术） 2022年第7期18卷 1190-1204页

作者： M.z.wu X.w.zhang Q.M.zhang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyHaidian DistrictBeijing10081China

Based on the two-arc profile assumption,the expansion deformation and energy absorption of circular tubes compressed by conical-cylindrical dies were ***,the deformation of the two arcs was analyzed independently and an improved model denoted as Model-I was ***,by further involving the coupling between the bending moment and membrane forces,a more elaborate model,i.e.,Model-II was ***,experiments and simulations were conducted to verify the models,which show that,compared with previous theoretical models,Model-II could not only capture the prominent features of the deformation,but also improve the prediction accuracy of the steady driving force *** means of this model,it was found that the critical semi-conical angle,which makes the driving force minimum,increases with the increase of the friction coefficient,expansion ratio as well as the radius/thickness ratio of the ***,the energy dissipation due to stretching is always greater than that of bending,while the friction dissipation can account for the largest proportion at small semi-conical angle or large friction *** a certain friction and die conditions,the specific energy absorption of expanded tubes can be much higher than that under progressive collapse mode.

关键词： Expansion Circular tube Stress coupling Strain hardening Energy absorption

Exergy analysis of R1234ze（z） as high temperature heat pump working fluid with multi-stage compression

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Frontiers in Energy 2017年第4期11卷 493-502页

作者： Bin HU Di wu L.w. wANG R.z. wANG Institute of Refrigeration and Cryogenics Shanghai Jiao Tong University Shanghai 200240 China

In this paper, the simulation approach and exergy analysis of multi-stage compression high tempera- ture heat pump （HTHP） systems with R1234ze（z） working fluid are conducted. Both the single-stage and multi-stage compression cycles are analyzed to compare the system performance with 120℃ pressurized hot water supply based upon waste heat recovery. The exergy destruction ratios of each component for different stage compression systems are compared. The results show that the exergy loss ratios of the compressor are bigger than that of the evaporator and the condenser for the single-stage compres- sion system. The multi-stage compression system has better energy and exergy etticiencies with the increase of compression stage number. Compared with the single- stage compression system, the coefficient of performance （COP） improvements of the two-stage and three-stage compression system are 9.1% and 14.6%, respectively. when the waste heat source temperature is 60℃, the exergy efficiencies increase about 6.9% and 11.8% for the two-stage and three-stage compression system respec- tively.

关键词： multi-stage compression high temperatureheat pump heat recovery exergy destruction,R1234ze(z) working fluid

A Model of Tangential Contact Damping Considering Asperity Interaction and Lateral Contact

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Acta Mechanica Solida Sinica 2018年第6期31卷 758-774页

作者： w.P.Fu z.Q.Gao w.wang J.B.wu School of Mechanical and Precision Instrument Engineering Xi'an University of TechnologyXi'an 710048 China

A precise tangential contact damping model is proposed,which includes the lateral contact of the upper-lower asperities and the interaction of adjacent *** effects of the normal static preload,frequency,and amplitude of tangential displacement on the tangential contact damping were analyzed by simulation,***,the results of simulation are verified by *** tangential contact damping of considering the interaction and lateral contact of asperity is very close to the experimental results.

关键词： Asperity Lateral contact Interaction Tangential contact damping

Bioinspired Passive Tactile Sensors Enabled by Reversible Polarization of Conjugated Polymers

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Nano-Micro Letters 2025年第1期17卷 361-377页

作者： Feng He Sitong Chen Ruili zhou Hanyu Diao Yangyang Han Xiaodong wu School of Mechanical Engineering Sichuan UniversityChengdu 610065People’s Republic of China School of Software Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065People’s Republic of China State Key Laboratory of Polymer Materials Engineering Sichuan UniversityChengdu 610065People’s Republic of China

Tactile perception plays a vital role for the human body and is also highly desired for smart prosthesis and advanced *** to active sensing devices,passive piezoelectric and triboelectric tactile sensors consume less power,but lack the capability to resolve static ***,we address this issue by utilizing the unique polarization chemistry of conjugated polymers for the first time and propose a new type of bioinspired,passive,and bio-friendly tactile sensors for resolving both static and dynamic ***,to emulate the polarization process of natural sensory cells,conjugated polymers(including poly(3,4-ethylenedioxythiophen e):poly(styrenesulfonate),polyaniline,or polypyrrole)are controllably polarized into two opposite states to create artificial potential *** controllable and reversible polarization process of the conjugated polymers is fully in situ ***,a micro-structured ionic electrolyte is employed to imitate the natural ion channels and to encode external touch stimulations into the variation in potential difference *** with the currently existing tactile sensing devices,the developed tactile sensors feature distinct characteristics including fully organic composition,high sensitivity(up to 773 mV N^(−1)),ultralow power consumption(nw),as well as superior *** demonstrations,both single point tactile perception(surface texture perception and material property perception)and two-dimensional tactile recognitions(shape or profile perception)with high accuracy are successfully realized using self-defined machine learning *** tactile sensing concept innovation based on the polarization chemistry of conjugated polymers opens up a new path to create robotic tactile sensors and prosthetic electronic skins.

关键词： Passive tactile sensors Reversible polarization of conjugated polymers Tactile perception Machine learning algorithm Object recognition

A betatron tune measurement system based on bunch-by-bunch transverse feedback at the Duke storage ring

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Chinese Physics C 2013年第7期37卷 76-82页

作者：徐卫 w. z. wu 李京祎何多慧 Y. K. wu National Synchrotron Radiation Laboratory (NSRL) University of Science and Technology of China FEL Laboratory TUNL and Department of Physics Duke University

To combat electron beam instabilities, a digital bunch-by-bunch transverse feedback （TFB） system has been developed for the Duke storage ring. while it is capable of suppressing transverse beam instabilities for multibunch operation, the TFB system has not been needed for typical operation of the Duke storage ring. To explore the great potential of this system, we have developed beam diagnostic techniques using the TFB, in particular, the TFB based tune measurement techniques. The tune measurement technique allows us to conduct fast chromaticity measurements, compared with the existing chromaticity measurement system using a network analyzer. This new tune measurement system also enables us to measure the bunch tune for multibunch operation of the Duke storage ring. with the TFB based tune measurement system, we have studied the tune stability of the electron beam in the Duke storage ring. This tune system has also been used to calibrate the tune knob for the Duke storage ring.

关键词： transverse feedback tune chromaticity