检索结果-南通市图书馆

Microstructure evolution of cold-sprayed coating during deposition and through post-spraying heat treatment

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

中国有色金属学会会刊：英文版 2004年第z1期14卷 49-54页

作者： li chang-jiu li Wen-ya State Key Laboratory for Mechanical Behavior of Materials Xi''an Jiaotong University Xi''an 710049 China State Key Laboratory for Mechanical Behavior of Materials Xi''an Jiaotong University Xi''an 710049 China

The microstructural features of cold-sprayed coatings were investigated using Cu, Ti and Zn feedstocks by optical microscopy, scanning electron microscopy and transmission electron microscopy to reveal the microstructure evolution mechanisms in cold spray. Four typical effects including tamping, refinement, impact-induced fusion and annealing were examined on microstrueture. It is found that the microstructure of cold spray coating is remarkably influenced by spray materials. Ti coatings consist of evident porous layer and Cu coatings present a limited porous layer only near the surface. It is clear that the successive tamping effect and dynamic refinement of grains significantly influence the microstructure evolution of cold-sprayed coating. The tamping effect leads to the densification of porous coating layer gradually and the refinement effect leads to the formation of fine microstructure. It is considered that the large difference in the formation of porous layer is attributed to the dynamic impact pressure and hardenability of materials. It is also found that the impact-induced fusion during deposition of Zn coating can also modify the interfacial microstructure between particles in cold spray coating. Moreover, the nanocrystalline phase can be formed at the interfaces among particles resulting from the localized melting of the interfaces and tamping effect. Furthermore, the annealing treatment can modify the microstructure and property of a cold-sprayed coating.

关键词： cold spraying coating microstructure evolution annealing treatment

Design and development of multi-channel front end electronics based on dual-polarity charge-to-digital converter for SiPM detector applications

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2期34卷 1-12页

作者： Yu‑Ying li chang‑Yu li Kun Hu Institute of Frontier and Interdisciplinary Science Shandong UniversityQingdao 266237China

With the development of silicon photomultiplier(SiPM)technology,front-end electronics for SiPM signal processing have been highly sought after in various fields.A compact 64-channel front-end electronics(FEE)system achieved by fieldprogrammable gate array-based charge-to-digital converter(FPGA-QDC)technology was built and *** FEE consists of an analog board and FPGA *** analog board incorporates commercial amplifiers,resistors,and *** FPGA board is composed of a low-cost *** electronics performance of the FEE was evaluated in terms of noise,linearity,and uniformity.A positron emission tomography(PET)detector with three different readout configurations was designed to validate the readout capability of the FEE for SiPM-based *** PET detector was made of a 15×15 lutetium–yttrium oxyorthosilicate(LYSO)crystal array directly coupled with a SiPM array *** experimental results show that FEE can process dual-polarity charge signals from the SiPM *** addition,it shows a good energy resolution for 511-keV gamma photons under the dual-end readout for the LYSO crystal array irradiated by a Na-22 ***,the FEE based on FPGA-QDC shows promise for application in SiPM-based radiation detectors.

关键词： Readout electronics Charge measurement Radiation detector Silicon photomultiplier Field-programmable gate array

Design and simulation of a Torus topology for network on chip

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2008年第4期19卷 694-701页

作者： Wu chang li Yubai Chai Song DSP Lab School of Communication and Information Engineering~Univ. of Electronic Science and Technology of China Chengdu 610054 P. R. China

Aiming at the applications of NOC （network on chip） technology in rising scale and complexity on chip systems, a Torus structure and corresponding route algorithm for NOC is proposed. This Torus structure improves traditional Torus topology and redefines the denotations of the routers. Through redefining the router denotations and changing the original router locations, the Torus structure for NOC application is reconstructed. On the basis of this structure, a dead-lock and live-lock free route algorithm is designed according to dimension increase. System C is used to implement this structure and the route algorithm is simulated. In the four different traffic patterns, average, hotspot 13%, hotspot 67% and transpose, the average delay and normalization throughput of this Torus structure are evaluated. Then, the performance of delay and throughput between this Torus and Mesh structure is compared. The results indicate that this Torus structure is more suitable for NOC applications.

关键词： network on chip Torus route System C simulation

Data-Driven Leader-Follower Output Synchronization for Networked Non-linear Multi-Agent Systems with Switching Topology and Time-Varying Delays

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2018年第1期31卷 87-102页

作者： li chang-Jiang liU Guo-Ping Center for Control Theory and Guidance Technology Harbin Institute of Technology Harbin 150001 China School of Engineering University of South Wales Pontypridd CF37 1DL UK Center for Control Theory and Guidance Technology Harbin Institute of Technology Harbin 150001 China

This paper studies the output synchronization problem for a class of networked non-linear multi-agent systems with switching topology and time-varying delays. To synchronize the outputs,a leader is introduced whose connectivity to the followers varies with time, and a novel data-driven consensus protocol based on model free adaptive control is proposed, where the reference input of each follower is designed to be the time-varying average of the neighboring agents＇ outputs. Both the case when the leader is with a prescribed reference input and the case otherwise are *** proposed protocol allows for time-varying delays, switching topology, and does not use the agent structure or the dynamics information implicitly or explicitly. Sufficient conditions are derived to guarantee the closed-loop stability, and conditions for consensus convergence are obtained, where only a joint spanning tree is required. Numerical simulations and practical experiments are conducted to demonstrate the effectiveness of the proposed protocol.

关键词： Data-driven networked nonlinear multi-agent system output synchronization switching topology time-varying delay

Free energy calculation of single molecular interaction using Jarzynski's identity method:the case of HIV-1 protease inhibitor system

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2012年第3期28卷 891-903页

作者： De-chang li Bao-Hua Ji Biomechanics and Biomaterials Lab Department of Applied MechanicsBeijing Institute of TechnologyKey Laboratory.of Dynamics and Control of Flight VehicleMinistry of Education100081 BeijingChina

Jarzynski＇ identity （JI） method was suggested a promising tool for reconstructing free energy landscape of biomolecular interactions in numerical simulations and ex- periments. However, JI method has not yet been well tested in complex systems such as ligand-receptor molecular pairs. In this paper, we applied a huge number of steered molec- ular dynamics （SMD） simulations to dissociate the protease of human immunodeficiency type I virus （HIV-1 protease） and its inhibitors. We showed that because of intrinsic com- plexity of the ligand-receptor system, the energy barrier pre- dicted by JI method at high pulling rates is much higher than experimental results. However, with a slower pulling rate and fewer switch times of simulations, the predictions of JI method can approach to the experiments. These results sug- gested that the JI method is more appropriate for reconstruct- ing free energy landscape using the data taken from experi- ments, since the pulling rates used in experiments are often much slower than those in SMD simulations. Furthermore, we showed that a higher loading stiffness can produce higher precision of calculation of energy landscape because it yields a lower mean value and narrower bandwidth of work distri- bution in SMD simulations.

关键词： Molecular dynamics simulation. Single molecu-lar interaction ~ Molecular biomechanics ~ Steered moleculardynamics ~ Free energy calculation

Corrosion resistance of an amino acid-bioinspired calcium phosphate coating on magnesium alloy AZ31

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第14期47卷 224-235页

作者： Xiao-li Fan chang-Yang li Yu-Bo Wang Yuan-Fang Huo Shuo-Qi li Rong-chang Zeng Corrosion Laboratory for light Metals College of Materials Science and EngineeringShandong University of Science and TechnologyQingdao 266590China School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450002China

An L-cysteine-bioinspired calcium phosphate(Ca-P)coating is prepared upon magnesium alloy AZ31 in a water bath at 60℃.FE–SEM,FTIR,XRD,electrochemical characterization,hydrogen evolution tests and XPS were used to evaluate the microstructure,chemistry and corrosion performance of the *** indicate that L-cysteine promotes the nucleation process of the coating and significantly increases its *** can be attributed to the complexation of the carboxyl group and mercapto group of L-cysteine with calcium ***,the obtained Ca-P coating possesses higher corrosion resistance than that prepared in L-cysteine-free bath.

关键词： Magnesium alloys Phosphate Coating Corrosion resistance Amino acid

Microstructure and mechanical properties in core of a carburizing 20CrNi2MoV bearing steel subjected to cryogenic treatment

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2021年第3期28卷 360-369页

作者： chang-sheng li Bin-zhou li Xin Jin Yu Wang State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819LiaoningChina Ansteel Group Ansteel Beijing Research InstituteBeijing102211China

Microstructure and mechanical properties in core of a carburizing 20CrNi2MoV bearing steel subjected to cryogenic treatment were *** treatment sample was quenched and tempered at 180℃ for 2 *** treatment samples were quenched,cryogenically treated at−80 and−196℃ for 4 h,slowly returned to room temperature and thereafter tempered at 180℃ for 2 h,and finally tempered at 180℃ for 2 *** scanning electron microscope,electron backscattering diffraction,X-ray diffraction and transmission electron microscope were adopted for microstructure *** results show that cryogenic treatment increases the fraction of high-angle grain boundaries and the precipitation of finely dispersed carbides in the matrix,decreases the volume fraction of inter-lath retained austenite,and hence improves the strength and *** with the conventional treatment,the hardness,yield strength and ultimate tensile strength of the steel after cryogenic treatment are increased by 11.7%,12.6%and 18.3%,respectively,while the impact energy is decreased by 9.8%.

关键词： Bearing steel Cryogenic treatment Lath martensite Retained austenite Mechanical property

Determination of L-phenylalanine by cucurbit[7]uril sensitized fluorescence quenching method

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

Chinese Chemical Letters 2011年第7期22卷 851-854页

作者： chang Feng li li Ming Du Hao Wu Ying Xia chang Analytical and Testing Center Shanxi Normal University Linfen 041004 China School of Chemistry and Materials Science Shanxi Normal University Linfen 041004 China

The determination method of L-phenylalartine （LPA） by fluorescence quenching was developed. The assay was based on the combination of the cucurbit[7]uril （CB [7]） with palmatine hydrochloride （PAL） reaction. In the presence of CB [7], the fluorescence of PAL was quenched by LPA which can be employed to detect LPA. Under the optimal conditions, a linear range 3.63 ×10^-8- 9.68 ×10^-6 mol/L and a detection limit 1.27 ×10^-8 mol/L of LPA were obtained. The relative standard deviation （R.S.D） was 1.8% obtained from a series of 11 standards each containing 6.05 ×10^-6 mol/L of LPA. This paper also discusses the mechanism of fluorescence indicator probe.

关键词： L-phenylalanine Palmatine hydrochloride Cucurbituril Fluorescent probe

Hard magnetization direction and its relation with magnetic permeability of highly grain-oriented electrical steel

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2014年第11期21卷 1077-1082页

作者： Hao Wang chang-sheng li Tao Zhu State Key Laboratory of Rolling and Automation Northeastern University

The magnetic properties of highly grain-oriented electrical steel vary along different directions. In order to investigate these properties, standard Epstein samples were cut at different angles to the rolling direction. The hard magnetization direction was found at an angle of 60° to the rolling direction. To compare the measured and fitting curves, when the magnetic field intensity is higher than 7000 A/m, it is appropriate to simulate the relation of magnetic permeability and magnetization angle using the conventional elliptical model. When the magnetic field intensity is less than 3000 A/m, parabolic fitting models should be used; but when the magnetic field intensity is between 3000 and 7000 A/m, hybrid models with high accuracy, as proposed in this paper, should be applied. Piecewise relation models of magnetic permeability and magnetization angle are significant for improving the accuracy of electromagnetic engineering calculations of electrical steel, and these new models could be applied in further industrial applications.

关键词： electrical steel magnetization direction magnetic permeability mathematical models