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EFFECT OF MICrOSTrUCTUrE ON COrrOSION FATIGUE BEHAVIOUr OF A LOW CArBON BAINITE STEEL

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Acta Metallurgica Sinica(English Letters) 1992年第7期5卷 43-47页

作者： ZHANG rong ZHOU Lubin, northwestern polytechnical university, xi’an, ChinaZHENG Wenlong HUA Huizhong, Shanghai research Institute of Materials, Shanghai, China ZHANG rong, Lecturer, department of applied physics, northwestern polytechnical university, xi’an 710072, China

The behaviour towards corrosion fatigue of low carbon bainite steel with various microstructures after temp.r.d at different temp.r.tures has been examined. The susceptibility of the steel to corrosion fatigue may be ... 详细信息

关键词： corrosion fatigue bainite retained austenite low carbon steel

Adaptive Output-feedback regulation for Nonlinear Delayed Systems Using Neural Network

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International Journal of Automation and computing 2008年第1期5卷 103-108页

作者： Wei-Sheng Chen Jun-Min Li department of applied mathematics,xidian {4.,xi′an 710071,prC department of applied mathematics Xidian University Xi’an 710071 PRC

A novel adaptive neural network （NN） output-feedback regulation algorithm for a class of nonlinear time-varying timedelay systems is proposed. Both the designed observer and controller are independent of time delay. Different from the existing results, where the upp.r.bounding functions of time-delay terms are assumed to be known, we only use an NN to compensate for all unknown upp.r.bounding functions without that assumption. The proposed design method is proved to be able to guarantee semi-global uniform ultimate boundedness of all the signals in the closed system, and the system output is proved to converge to a small neighborhood of the origin. The simulation results verify the effectiveness of the control scheme.

关键词： Adaptive neural network (NN) output-feedback nonlinear time-delay systems backstepping

The complex variable reproducing kernel p.r.icle method for elasto-plasticity problems

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Science China(physics,Mechanics & Astronomy) 2010年第5期53卷 954-965页

作者： CHEN Li1 & CHENG YuMin2 1 department of Engineering Mechanics,Chang’an university,xi’an 710064.China 2 Shanghai Institute of applied {4. and Mechanics,Shanghai university,Shanghai 200072,China 1. department of Engineering Mechanics Chang’an University Xi’an 710064 China2. Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China

On the basis of reproducing kernel p.r.icle method(rKpM),using complex variable theory,the complex variable reproducing kernel p.r.icle method(CVrKpM) is discussed in this *** advantage of the CVrKpM is that the correction function of a two-dimensional problem is formed with one-dimensional basis function when the shape function is *** the CVrKpM is applied to solve two-dimensional elasto-plasticity *** Galerkin weak form is employed to obtain the discretized system equation,the penalty method is used to apply the essential boundary *** then,the CVrKpM for two-dimensional elasto-plasticity problems is formed,the corresponding formulae are obtained,and the Newton-raphson method is used in the numerical *** numerical examples are given to show that this method in this pap.r.is effective for elasto-plasticity analysis.

关键词： meshless method reproducing kernel p.r.icle method(rKpM) complex variable reproducing kernel p.r.icle method(CVrKpM) correction function elasto-plasticity

preface to the Special Issue in Celebration of professor Shouwen Yu’s 85th Birthday

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Acta Mechanica Solida Sinica 2024年第3期37卷 361-362页

作者： xi-Qiao Feng Qunyang Li department of Engineering Mechanics Tsinghua UniversityBeijing100084China

Shouwen Yu,Emeritus professor of applied Mechanics at Tsinghua university,was born on May 4.1939 in xianyou County,Fujian province,*** p.r.ued his undergraduate studies from 1955 to 1958 in the {4. of Civil Str... 详细信息

关键词： Fujian preface p.r.ue

AN　INVESTIGATION　OF　CHEMICAL　SHOrT　CrACK　CHArACTErISTICS　IN　GC－4.HIGH－STrENGTH　STEEL

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Chinese Journal of Aeronautics 1994年第4期7卷 295-300页

作者： Wang rong Lou Minxiu Zheng xiulin(northwestern polytechnical university, xi’an, China, {4.)

A method of constant △K value is applied exp.r.mentally to investigatechemical short crack characteristics of GC-4.high-strength steel in 3.5%NaClsolution. Exp.r.mental results show that there is a critical point of crack geometry aon da / dN-a curve of the crack propagation at constant △K value. When the cracklength a rt crack effect appears. The value of a is almost not af-fected by the loading frequency, stress ratio and △K level. The ratio of characteristiccrack propagation rate of chemical short cracks to that of long cracks is a weak func-tion of the loading frequency, stress ratio and △K level. Based on the analysis, the rela-tion between the short crack propagation rate and crack size is suggested.

关键词： high strength steel chemical prop.r.ies short cracks crack propagation

Adaptive Fuzzy Dynamic Surface Control for a Class of p.r.urbed Nonlinear Time-varying Delay Systems with Unknown Dead-zone

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International Journal of Automation and computing 2012年第5期9卷 545-554页

作者： Hong-Yun Yue Jun-Min Li department of applied mathematics,xidian {4.,xi an 710071,China 1. department of applied mathematics Xidian University Xi’an 710071 China

In this pap.r.adaptive dynamic surface control(DSC) is developed for a class of nonlinear systems with unknown discrete and distributed time-varying delays and unknown *** logic systems are used to ap.r.ximate the unknown nonlinear ***,by combining the backstepping technique and the ap.r.priate Lyapunov-Krasovskii functionals with the dynamic surface control ap.r.ach,the adaptive fuzzy tracking controller is *** development is able to eliminate the problem of 'explosion of complexity' inherent in the existing backstepping-based *** main advantages of our ap.r.ach include:1) for the n-th-order nonlinear systems,only one p.r.meter needs to be adjusted online in the controller design procedure,which reduces the computation burden ***,the input of the dead-zone with only one adjusted p.r.meter is much simpler than the ones in the existing results;2) the proposed control scheme does not need to know the time delays and their upp.r.*** is proven that the proposed design method is able to guarantee that all the signals in the closed-loop system are bounded and the tracking error is smaller than a prescribed error bound,Finally,simulation results demonstrate the effectiveness of the proposed ap.r.ach.

关键词： Adaptive fuzzy control dynamic surface control(DSC) discrete and distributed time-varying delays Lyapunov-Krasovskii functionals dead-zone

Adaptive　Multisensor　Tracking　Fusion　Algorithm　for　Air－borne　Distributed　passive　Sensor　Network

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Journal of Systems Engineering and Electronics 1996年第3期7卷 15-23页

作者： Zhen Ding Hongcai Zhang & Guanzhong Dai (department of Automatic Control, northwestern polytechnical universityShaanxi, xi’an 710072, {4.China) department of Automatic Control Northwestern Polytechnical University Shaanxi Xi'an 710072 P.R. China

Single passive sensor tracking algorithms have four disadvantages: bad stability, longdynamic time, big bias and sensitive to initial conditions. So the corresponding fusion algorithm results in bad p.r.ormance. A new error analysis method for two passive sensor tracking system is presented and the error equations are deduced in detail. Based on the equations, we carry out theoretical computation and Monte Carlo computer simulation. The results show the correctness of our error computation equations. With the error equations, we present multiple 'two station'fusion algorithm using adaptive pseudo measurement equations. This greatly enhances the tracking p.r.ormance and makes the algorithm convergent very fast and not sensitive to initial *** results prove the correctness of our new algorithm.

关键词： passive tracking system Error analysis Fusion algorithm Distributed passive sensornetwork Distributed estimation.

DESIGN prOBLEMS OF THrEEDIMENSIONAL CONTrACTIONS

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Chinese Journal of Aeronautics 1993年第1期 25-31页

作者： Su Yao-xi,Lin Chao-qiang,Hong Liu (northwestern polytechnical university,xi’an,China,710072)

The numerical analysis of incompressible flow in rectangular contractions is p.r.ormedby using a finite-difference method and body-fitted coordinates. Three types ofcommonly used wall contours are chosen and comp.r.d, i.e., contours with Witozinskycurve, the 5-th power curve and matched cubic curves respectively. Two desigh criteriahave been generally used for axisymmetric contractions, i.e., (1) no sep.r.tion on nozzledwalls, (2) nonuniformity at exit cross section lower than 2%. These criteria are revised andapplied to three-dimensional contractions to comp.r. the p.r.ormance of the above-mentionedthree types of contours. It is found that the contour with matched cubic curves, whenoptimized, gives the most satisfactory results, while the contour with Witozinsky curve p.r.ormsbadly because of serious adverse pressure gradient near the entrance. Some problemsof three-dimensional contraction design are discussed. The cross section similaritywhich is usually considered as a requirement in three-dimensional contraction design practiceis found to be of no real value.

关键词： Design In DESIGN prOBLEMS OF THrEEDIMENSIONAL CONTrACTIONS Wind length

Traditional Chinese Medicine Integrated responsive Microneedles for Systemic Sclerosis Treatment

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research 2024年第1期2023卷 139-147页

作者： xi Luan xiaoxuan Zhang Min Nie Yuanjin Zhao department of rheumatology and Immunology Nanjing Drum Tower HospitalSchool of PharmacyClinical College of Traditional Chinese and Western MedicineNanjing University of Chinese MedicineNanjing 210023China State Key Laboratory of Bioelectronics School of Biological Science and Medical EngineeringSoutheast UniversityNanjing 210096China

Traditional Chinese medicine,such as Tripterygium wilfordii and paeonia lactiflora,has potential values in treating systemic sclerosis(SSc)and other autoimmune diseases,while their toxic side effect elimination and precise tropical drug delivery are still ***,we present multiple traditional Chinese medicine integrated photoresponsive black phosphorus(Bp)microneedles(MNs)with the desired features for the SSc *** employing a template-assisted layer-by-layer curing method,such MNs with triptolide(Tp)/paeoniflorin(pae)needle tips and Bp-hydrogel needle bottoms could be well *** combined administration of Tp and pae can not only provide anti-inflammatory,detoxification,and immunomodulatory effects to treat skin lesions in the early stage of SSc but also remarkably reduce the toxicity of single drug ***,the additive Bps possess good biocompatibility and near-infrared(NIr)responsiveness,imp.r.ing the MN photothermal-controlled drug release *** on these features,we have demonstrated that the traditional Chinese medicine integrated responsive MNs could effectively improve skin fibrosis and telangiectasia,reduce collagen deposition,and reduce epidermal thickness in the SSc mouse *** results indicated that the proposed Chinese medicine integrated responsive MNs had enormous potential in clinical therapy of SSc and other diseases.

关键词： needle precise template