检索结果-南通市图书馆

Design and development of SiC/(W,Ti)C gradient ceramic nozzle

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2008年第1期51卷 77-84页

作者： LIU LiLi DENG JianXin WANG Yi zhu lina Department of Mechanical Engineering Shandong UniversityJinan 250061China School of Mechanical and Electrical Pingyuan UniversityXinxiang 453003China School of Mechanical and Electrical Beijing Jiaotong UniversityBeijing 100045China

The idea of functionally gradient material (FGM) theory was used to design ceramic nozzle based on the erosion wear behaviors of the ceramic nozzles and the out- standing properties of FGM. The purpose is to reduce the tensile stress at the entry region of the nozzle during sand blasting processes. The design theory and methods of gradient ceramic nozzle were proposed. The physical, micromechanical, and composition distribution models of gradient ceramic nozzle were established. The optimum composition distribution of the gradient ceramic nozzle material was determined from the solution of the multi-objective optimization calculation by constructing the models of the composition distribution versus the structural in- tegrity of the compact in fabricating process. Results showed that compressive residual stresses appeared at the entry area of the gradient ceramic nozzle. The optimized component distribution exponent p is 0.5. An SiC/(W,Ti)C gradient ce- ramic nozzle material was synthesized by hot-pressing according to the design result. Results showed that the surface Vickers hardness of the FGM-1 gradient ceramic nozzle materials was greatly improved in comparison with that of the other layers.

关键词： ceramic nozzle erosion wear function gradient material stress Finite element analysis

Physical Layer Authentication in Wireless Communication Networks:A Survey

在线全文

学校读者我要写书评

暂无评论

Journal of Communications and Information Networks 2020年第3期5卷 237-264页

作者： Lin Bai lina zhu Jianwei Liu Jinho Choi Wei Zhang School of Cyber Science and Technology Beihang UniversityBeijing 100191China School of Electronic and Information Engineering Beihang UniversityBeijing 100191China School of Information Technology Deakin UniversityBurwoodVIC 3125Australia School of Electrical Engineering and Telecommunications The University of New South WalesSydneyNSW 2052Australia

Physical layer security(PLS)in wireless communication systems has attracted extensive research attentions in recent *** cryptography-based methods applied in upper-layer in network,PLS methods are applied in physical layers and can provide information-theoretic security by utilizing the randomness of signals and wireless *** this survey,we provide a comprehensive review in the domain of physical layer authentication(PLA)in wireless communication systems,including the concepts,several key techniques of typical PLA architectures as well as future challenges and research trends in more sophisticated communication *** survey begins with an overview of the background and basic concepts of PLA,such as the general model of wireless security communication system,typical frameworks of key-based/less PLA systems,and the common attack *** then discuss the major concerns and key techniques that are applied in PLA systems,where three types of authentication schemes are considered,i.e.,the authentication based on channel information,radio-frequency and identity *** models and representative research results about key approaches and techniques applied to the authentication systems above are subsequently ***,the associated challenges and potential research trends of PLA in future communication systems are presented at the end of the survey paper.

关键词： physical layer authentication(PLA) radiofrequency identification hypothesis testing wireless communication

Research on fault diagnosis method of piston rod based on harmonic wavelet and manifold learning

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Technology Letters 2018年第3期24卷 232-240页

作者：江志农 zhu lina Zhang Jinjie Zhou Chao Diagnosis and Self-recovering Engineering Research Center Beijing University of Chemical TechnologyBeijing 1013029P.R.China Compressor Health and Intelligent Monitoring Center of National Key Laboratory of Compressor Technology Beijing University of Chemical TechnologyBeijing 100029P.R.China

As the core part of reciprocating compressor,piston rod is easy to cause a serious accident when abrasion and breakage fault occur to it. Therefore,it is very important to monitor its running state. At present,a small number of reciprocating compressors have been installed on-line monitoring and diagnosis system,most of which can only monitor a single vertical subsidence of piston rod and it can't fully represent the running state of piston rod. Therefore,a method of monitoring the vertical and horizontal displacement of piston rod axis orbit is simultaneously used. In view of the characteristics that the piston rod axis orbit is disordered and difficult to extract features,purification of the axis orbit is carried out based on harmonic wavelet and then features are extracted such as vibration energy,natural frequency and the axis orbit envelope area. After that,a nonlinear local tangent space manifold learning algorithm is used to reduce the dimension of the features and obtain sensitive features. By analyzing the practical cases,the effectiveness of the method for fault monitoring and diagnosis of reciprocating compressor piston rod assembly has been verified. Finally,as BP neural network has the characteristics of solving complex nonlinear problems,the validity of the fault diagnosis method of reciprocating compressor piston rod based on harmonic wavelet and manifold learning is proved by actual case data analysis based on BP neural network.

关键词： piston rod reciprocating compressor axis orbit harmonic wavelet manifold learning

An apodized cubic phase mask used in a wavefront coding system to extend the depth of field

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第5期31卷 422-428页

作者： lina zhu Fei Li Zeyu Huang Tingyu Zhao Department of Physics Key Laboratory of Optical Field Manipulation of Zhejiang ProvinceZhejiang Sci-Tech UniversityHangzhou 310018China

The point spread function(PSF)caused by a wavefront coding system with a cubic phase mask has big side-lobes which leads to bad image *** paper proposes a novel apodized cubic phase mask to suppress the side-lobes of the *** annealing algorithm is used to optimize the cubic and the truncation parameter of the phase *** system with the novel phase mask has better performance in the modulation transfer function(MTF)especially in low-and-medium spatial frequency *** simulation results show that the restored images with the novel phase mask are superior to the one with the classic cubic phase mask in contrast and ringing *** experimental results show that the side-lobes of the PSF are suppressed by using the apodized cubic phase mask.

关键词： apodized cubic phase mask wavefront coding depth of field image restoration

Metallurgy Failure Analysis for an Early Fracture Engine Intake Valve Made of 85Cr18Mo2V

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2012年第S1期41卷 148-151页

作者： Zhang Yubo Xu Binshi Wang Haidou Yang Daxiang lina, zhu Acad Armored Forces Engn Natl Key Lab Remfg Beijing 100072 Peoples R China

By means of analysis technique such as scanning electron microscopy(SEM)equipped with energy dispersive spectroscopy(EDS),and transmission electron microscopy(TEM),deep metallurgy failure analysis for an early fracture engine intake valve made of the martensite material of 85Cr18Mo2V was performed through macroscopical and microcosmic as well as chemical composition *** to the result of SEM,this valve belonged to fatigue *** crack sources of dense micro-holes near the surface of intake valve and SiO2 impurity are the direct reasons to cause the valve *** EDS analysis for the fatigue source region approved that superfluous Si,O and Al impurity *** TEM observation of the slice cut from the region closing to the fracture surface showed that deep areas near the surface of valve were oxidized *** material structure got brittle due to the generation of *** will be produced in these oxidation areas under high cycle fatigue ***,the synthetical action of various factors finally caused the fracture of valve.

关键词： intake valve fatigue fracture 85Cr18Mo2V failure analysis interior oxidation

Wind Speed Short-Term Prediction Based on Empirical Wavelet Transform, Recurrent Neural Network and Error Correction

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2024年第2期29卷 297-308页

作者：朱昶胜朱丽娜 School of Computer and Communication Lanzhou University of TechnologyLanzhou 730050China

Predicting wind speed accurately is essential to ensure the stability of the wind power system and improve the utilization rate of wind ***,owing to the stochastic and intermittent of wind speed,predicting wind speed accurately is difficult.A new hybrid deep learning model based on empirical wavelet transform,recurrent neural network and error correction for short-term wind speed prediction is proposed in this *** empirical wavelet transformation is applied to decompose the original wind speed *** long short term memory network and the Elman neural network are adopted to predict low-frequency and high-frequency wind speed sub-layers respectively to balance the calculation efficiency and prediction *** error correction strategy based on deep long short term memory network is developed to modify the prediction *** actual wind speed series are utilized to verify the effectiveness of the proposed *** empirical results indicate that the method proposed in this paper has satisfactory performance in wind speed prediction.

关键词： wind speed prediction empirical wavelet transform deep long short term memory network Elman neural network error correction strategy

Effects of annealing treatment on tribological behavior of tungsten-doped diamond-like carbon film under lubrication(Part 2):Tribological behavior under MoDTC lubrication

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2022年第7期10卷 1061-1077页

作者： Shaojun ZHANG lina zhu Yanyan WANG Jiajie KANG Haidou WANG Guozheng MA Haipeng HUANG Guang’an ZHANG Wen YUE School of Engineering and Technology China University of Geosciences(Beijing)Beijing 100083China Zhengzhou Research Institute China University of Geosciences(Beijing)Zhengzhou 451283China National Engineering Research Center for Remanufacturing Beijing 100072China National Key Lab for Remanufacturing Academy of Armored Forces EngineeringBeijing 100072China Beijing Research Institute Sinopec Lubricant Co.Ltd.Beijing 100085China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

Molybdenum dialkyldithiocarbamate(MoDTC)is widely used as a friction modifier in engine lubricating *** MoDTC lubrication,the friction and wear behaviors of tungsten-doped diamond-like carbon(W-DLC)films annealed at 100-400℃were discussed and evaluated using scanning electron microscopy(SEM),atomic force microscopy(AFM),and Raman ***(polymerized alpha olefin)PAO+MoDTC lubrication,the coefficient of friction of all samples decreased,but the wear rates of the W-DLC films annealed at 300℃increased *** interacting with zinc dialkyldithiophosphate(ZDDP),the wear rates of W-DLC films annealed at different temperatures declined significantly owing to the formation of dense phosphate tribofilms on the worn surfaces.

关键词： diamond-like carbon(DLC) annealing friction and wear behaviors molybdenum dialkyldithiocarbamate(MoDTC) zinc dialkyldithiophosphate(ZDDP)

An overview on CV2/CRMP5 antibody-associated paraneoplastic neurological syndromes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2023年第11期18卷 2357-2364页

作者： Sai Wang Haiman Hou Yao Tang Shuang Zhang Gege Wang Ziyan Guo lina zhu Jun Wu Department of Neurology The First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan ProvinceChina

Paraneoplastic neurological syndrome refers to certain malignant tumors that have affected the distant nervous system and caused corresponding dysfunction in the absence of tumor *** with this syndrome produce multiple antibodies,each targeting a different antigen and causing different symptoms and *** CV2/collapsin response mediator protein 5(CRMP5)antibody is a major antibody of this *** damages the nervous system,which often manifests as limbic encephalitis,chorea,ocular manifestation,cerebellar ataxia,myelopathy,and peripheral *** CV2/CRMP5 antibody is crucial for the clinical diagnosis of paraneoplastic neurological syndrome,and anti-tumor and immunological therapies can help to alleviate symptoms and improve ***,because of the low incidence of this disease,few repo rts and no reviews have been published about it so *** article intends to review the research on CV2/CRMP5antibody-associated paraneoplastic neurological syndrome and summarize its clinical features to help clinicians comprehensively understand the ***,this review discusses the curre nt challenges that this disease poses,and the application prospects of new detection and diagnostic techniques in the field of paraneoplastic neurological syndrom e,including CV2/CRMP5-associated paraneoplastic neurological syndrome,in recent years.

关键词： autoimmunity CRMP5 CV2 CV2/CRMP5 antibody paraneoplastic neurological syndromes paraneoplastic syndromes tumor

Controllable NO Release for Catheter Antibacteria from Nitrite Electroreduction over the Cu-MOF

在线全文

学校读者我要写书评

暂无评论

Transactions of Tianjin University 2023年第4期29卷 275-283页

作者： Yibo Wang Yutian Qin Wei Li Yuting Wang lina zhu Meiting Zhao Yifu Yu Institute of Molecular Plus Department of ChemistrySchool of ScienceTianjin UniversityTianjin 300072China Tianjin Key Laboratory of Molecular Optoelectronic Sciences Department of ChemistryInstitute of Molecular Aggregation ScienceTianjin UniversityTianjin 300072China College of Chemistry Nankai UniversityTianjin 300071China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

Implant-associated infections caused by biomedical catheters severely threaten patients'*** use of electrochemical control on NO release from benign nitrite equipped in the catheter can potentially resolve this issue with excellent *** by nitrite reductase,a Cu-BDC(BDC:benzene-1,4-dicarboxylic acid)catalyst with coordinated Cu(Ⅱ)sites was constructed as a heterogeneous electrocatalyst to control nitrite reduction to nitric oxide for catheter *** combined results of in situ and ex situ tests unveil the key function of interconversion between Cu(Ⅱ)and Cu(Ⅰ)species in NO_(2)^(-)reduction to *** being incorporated into the actual catheter,the Cu-BDC catalyst exhibits high electrocatalytic activity toward NO_(2)^(-)reduction to NO and excellent antibacteria efficacy with a sterilizing rate of 99.9%,paving the way for the development of advanced metal-organic frameworks(MOFs)electrocatalysts for catheter antibacteria.

关键词： Heterogeneous electrocatalysis Nitrite electroreduction NO-releasing catheter Antibacterial MOF material