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Acta Mechanica Solida Sinica 2016年第5期29卷 468-478页

作者： Yangyang Luo min Tang qiao Ni Yikun Wang Lin Wang Department of Mechanics Huazhong University of Science and Technology Wuhan 430074 China Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment Wuhan 430074 China wuhan Second Ship Design and Research Institute Wuhan 430205 China

In this paper,the nonlinear dynamics of a curved pipe is investigated in the case of principal parametric resonance due to pulsating flow and impact with loose *** coupled in-plane and out-of-plane governing equations with the consideration of von Karman geometric nonUnearity are presented and discretized via the differential quadrature method（DQM）.The nonlinear dynamic responses are calculated numerically to demonstrate the influence of pulsating ***,the impact is taken into *** influence of clearance on frettingwear damage,such as normal work rate,contact ratio and impact force level,is demonstrated.

关键词： curved governing quadrature clearance Karman numerically loose conveying parametric dynamical

Integral inference method for da/dN-ΔK and P-da/dN-ΔK curves

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航空动力学报 2011年第6期26卷 1251-1256页

作者： FU Hui-min wu Qiong Research Center of Small Sample Technology Beijing University o~ Aeronautics and Astronautics Beijing 100191 China

The integral inference method for fatigue crack growth(FCG) curve was established based on the two-variance regression *** estimates of da/dN-ΔK curve and P-da/dN-ΔK curve with high confidence level and high survival probability were also *** data scatter with stress intensity factor ranges in reality,which limits the group test method's *** presented method analyzes FCG curve as an integration,thus it can exploit the lengthwise information among the FCG rates corresponding to different stress intensity factor ***,compared with group test method,the presented method can not only save specimens,but also have higher precision in the evaluations of da/dN-ΔK and P-da/dN-ΔK curves.

关键词： aero-engine fatigue crack growth(FCG) crack growth rate integral estimate reliability

EVALUATION OF THREE-DIMENSIONAL NUMERICAL MODEL FOR SALINE INTRUSION AND PURGING IN SEWAGE OUTFALLS

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Journal of Hydrodynamics 2007年第1期19卷 48-53页

作者： wu Wei YAN Zhong-min College of Water Conservancy and Hydropower Engineering Hohai University Nanjing 210098 China

Saline intrusion into sewage outfalls will greatly decrease the efficiency of the structures. The numerical model for this flow has been limited to one- and two-dimensional ones. In this article, a three-dimensional numerical model for saline intrusion and purging in sewage outfalls was developed. The flow was modeled in three dimensions under turbulent conditions with the RNG k-ε turbulence model. The numerical results provided quantitative evidence of the fundamental flow mechanisms that took place during saline intrusion and purging. The comparisons of the results with that of two-dimensional model and that of experiments indicate that the three-dimensional numerical model developed in this article is more effective in predicting the internal flow in outfalls.

关键词： saline intrusion sea ouffalls numericalsimulation three-dimensional numerical model

Generator,multiquadric generator,quasi-interpolation and multiquadric quasi-interpolation

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Applied Mathematics(A Journal of Chinese Universities) 2011年第4期26卷 390-400页

作者： wu Zong-min MA Li-min Shanghai Key Laboratory for Contemporary Applied Mathematics. School of Mathematical Sciences Fudan University Shanghai 200433 China.

The aim of this survey paper is to propose a new concept ＂generator＂. In fact, generator is a single function that can generate the basis as well as the whole function space. It is a more fundamental concept than basis. Various properties of generator are also discussed. Moreover, a special generator named multiquadric function is introduced. Based on the multiquadric generator, the multiquadric quasi-interpolation scheme is constructed, and furthermore, the properties of this kind of quasi-interpolation are discussed to show its better capacity and stability in approximating the high order derivatives.

关键词： Generator function representation approximation numerical differentiation multiquadric quasi-interpolation

Surface effects on cylindrical indentation of a soft layer on a rigid substrate

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Acta Mechanica Sinica 2020年第2期36卷 422-429页

作者： min Li Huan-Xin Zhang Zi-Long Zhao Xi-qiao Feng Institute of Biomechanics and Medical Engineering AMLDepartment of Engineering MechanicsTsinghua UniversityBeijing 100084China

In this paper,theoretical and numerical methods are combined to investigate the two-dimensional,cylindrical indentation of an elastic soft layer bonded on a rigid *** incorporating the Gurtin-Murdoch’s theory of surface elasticity into the Kerr model,we account for surface effects on the indentation behavior of a soft *** governing differential relation between the surface pressure and displacement of the film-substrate system is *** an incompressible thin layer,the explicit solutions are derived,which are simple and *** element simulations are performed using an explicit restart algorithm to study the indentation properties of the layer-substrate system and to examine the validity and accuracy of the theoretical *** work holds promise for applications in mechanical characterization of soft materials,such as biological tissues and cells.

关键词： Soft materials Indentation Surface effect Contact Kerr model

Near-infrared chemical imaging for quantitative analysis of chlorpheniramine maleate and distribution homogeneity assessment in pharmaceutical formulations

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Journal of Innovative Optical Health Sciences 2016年第6期9卷 12-20页

作者： Manfei Xu Luwei Zhou qiao Zhang Zhisheng wu Xinyuan Shi Yanjiang qiao Beijing University of Chinese Medicine P.R.China 100102 Pharmaceutical Engineering and New Drug Development of Traditional Chinese Medicine(TCM)of ministry of Education P.R.China 100102 Key Laboratory of TCM-information Engineering of State Administration of TCM Beijing P.R.China 100102 Beijing Key Laboratory for Basic and Development Research on Chinese Medicine Beijing P.R.China 100102

Near infrared chemical imaging(NIR-CI)combines conventional near infrared(NIR)spectros-copy with chemical imaging,thus provides spectral and spatial information simult *** could be utilized to visualize the spatial distribution of the ingredients in a *** data acquired using NIR CI instrument are hyperspectral data cube(hypercube)containing thousands of *** methodologies are necessary to transform spectral information into chemical *** least squares(PLS)method was performed to extract chemical information of chlorpheniramine maleate in pharmaceutical formulations.A series of samples which consisted of different CPM concentrations(w/w)were compressed and hypercube data were *** spectra extracted from the hypercube were used to establish the PLS model of *** results of the model were R^(2)_(val)0.981,RMSEC 0.384%,RMSECV 0.483%,RMSEP 0.631%,indicating that this model was reliable.

关键词： Near infrared chemical imaging partial least squares regression assessment of distributional homogeneity chlorpheniramine maleate

Mechanical Properties of Laser Welded Joints of High Volume Fraction SiCp/Al Aluminum Matrix Composite

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第3期35卷 522-528页

作者： Hao Xiuqing Li Liang Song Xiaolu wu qiao College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016P.R.China

High volume fraction SiCp/Al aluminum matrix composite possesses a variety of outstanding properties,such as high thermal conductivity and low coefficient of thermal *** is widely applied in many fields,especially in automotive and *** orthogonal experiment is conducted to study the effects of relevant parameters on the mechanical properties by CO2 *** the micro-hardness in different regions is *** effects of such parameters as laser power,middle layer thickness and welding speed on the tensile strength of the welded joints are *** experimental results indicate that the maximum of the tensile strength of the welded joints is attained at the laser power of 1 200 W,the welding speed of 1.5 m/min and the middle layer thickness of 0.3 *** addition,the mechanism of the improvement of micro-hardness on the weld bead is also *** technology, surface tribology, wetting behavior and friction reduction.

关键词： micro-hardness mechanical properties laser welding aluminum matrix composite

Mutations in the SARS-CoV-2 spike receptor binding domain and their delicate balance between ACE2 affinity and antibody evasion

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Protein & Cell 2024年第6期15卷 403-418页

作者： Song Xue Yuru Han Fan wu qiao Wang Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS) Shanghai Institute of Infectious Disease and BiosecurityShanghai Frontiers Science Center of Pathogenic Microorganisms and InfectionSchool of Basic Medical SciencesShanghai Medical CollegeFudan UniversityShanghai 200032China

Intensive selection pressure constrains the evolutionary trajectory of SARS-CoV-2 genomes and results in various novel variants with distinct mutation *** mutations,particularly those within the receptor binding domain(RBD)of SARS-CoV-2 spike(S)protein,lead to the functional alteration in both receptor engagement and monoclonal antibody(mAb)***,we review the data of the RBD point mutations possessed by major SARS-CoV-2 variants and discuss their individual effects on ACE2 affinity and immune *** single amino acid substitutions within RBD epitopes crucial for the antibody evasion capacity may conversely weaken ACE2 binding ***,this weakened effect could be largely compensated by specific epistatic mutations,such as N501Y,thus maintaining the overall ACE2 affinity for the spike protein of all major *** predominant direction of SARS-CoV-2 evolution lies neither in promoting ACE2 affinity nor evading mAb neutralization but in maintaining a delicate balance between these two ***,this review interprets how RBD mutations efficiently resist antibody neutralization and meanwhile how the affinity between ACE2 and spike protein is maintained,emphasizing the significance of comprehensive assessment of spike mutations.

关键词： ACE2 affinity maintained

Research on Concrete Beam Crack Recognition Algorithm Based on Block Threshold Value Image Processing

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Structural Durability & Health Monitoring 2020年第4期14卷 355-374页

作者： Wenting qiao Xiaoguang wu Wen Sun Qiande wu School of Highway Chang'an UniversityXi'an710064China Iner Mongolia Transport Construction Engineering Quality Supervision Bureau Hohhot010020China Jiangsu Fasten Matenial Analysis and Inspecting Co LtdJiangyin214446China School of Civil Engineering Southeast UniversityNanjing210000China

To solve the problem that the digital image recognition accuracy of concrete structure cracks is not high under the condition of uneven ill umination and complex surface color of concrete structure,this paper has proposed a block segmentation method of maximum entropy threshold based on the digital image data obtained by the ACTIS automatic detection *** steps in this research are as follows:*** crack digital images of concrete specimens with typical fea-tures were collected by using the Actis system of KURABO Co,Ltd,of Japan in the concrete beam bending *** images are segmented into blocks to dis-tinguish backgrounds of different *** max imum interclass average gray difference method is used to distinguish the sub-blocks and screen out the image blocks that need to be *** is made to the image with 2D max imum entropy threshold segmentation method to obtain the binary image,and the target image can be obtained by screening the connected domain features of the binary *** have shown that compared with other algo-rithms,the proposed method can effectively decrease the image over-segmentation and under segmentation rates,highlight the characteristics of the target cracks,solve the problems of excessive difference between the identified length and actual length of cracks caused by background gray level change and uneven ilumnination,and effectively improve the recognition accuracy of bridge concrete cracks.

关键词： Concrete crack block segmentation maximum entropy segmentation algorithms maximum interclass variance(Otsu)method

Numerical Study on the Stress–Strain Cycle of Thermal Self-Compressing Bonding

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Chinese Journal of Mechanical Engineering 2018年第4期31卷 140-147页

作者： Yun-Hua Deng qiao Guan Jun Tao Bing wu Aeronautical Key Laboratory for Welding and Joining Technologies AVIC Beijing Aeronautical Manufacturing Technology Research Institute School of Mechanical Engineering and Automation Beihang University Science and Technology on Power Beam Process Laboratory AVIC Beijing Aeronautical Manufacturing Technology Research Institute

Thermal self-compressing bonding(TSCB) is a new solid-state bonding method pioneered by the authors. With electron beam as the non-melted heat source, previous experimental study performed on titanium alloys has proved the feasibility of TSCB. However, the thermal stress–strain process during bonding, which is of very important significance in revealing the mechanism of TSCB, was not analysed. In this paper, finite element analysis method is adopted to numerically study the thermal elasto-plastic stress–strain cycle of thermal self-compressing bonding. It is found that due to the localized heating, a non-uniform temperature distribution is formed during bonding, with the highest temperature existed on the bond interface. The expansion of high temperature materials adjacent to the bond interface are restrained by surrounding cool materials and rigid restraints, and thus an internal elasto-plastic stress–strain field is developed by itself which makes the bond interface subjected to thermal compressive action. This thermal self-compressing action combined with the high temperature on the bond interface promotes the atom diffusion across the bond interface to produce solid-state joints. Due to the relatively large plastic deformation, rigid restraint TSCB obtains sound joints in relatively short time compared to diffusion bonding.

关键词： Thermal self-compressing bonding Locally non-melted heating Thermal elasto-plastic stress–strain Atom diffusion Solid-state bonding Finite element analysis