检索结果-南通市图书馆

Effects of Additives on the Microstructure and Tribology Performance of Ta-12W Alloy Micro-Arc Oxidation Coating

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 142-149页

作者：刘玲 hu Changgang CHENG Wendong 刘兴泉 School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 610054China

Oxide ceramic coatings were fabricated on tantalum alloys by micro-arc oxidation (MAO) to improve their hardness and tribological properties. The MAO coatings were manufactured in a mixed silicatephosphate electrolyte containing NaF and/or EDTA (ethylene diamine tetraacetic acid). The surface morphology,cross-sectional view, chemical composition, hardness, and wear performance of the coatings were analysed. As revealed by the scanning electron microscopy, silica-rich nodules appear on the MAO coating obtained in the silicate-phosphate electrolyte, but the formation of nodules is inhibited with NaF and/or EDTA in the ***, they reduce the roughness and improve the compactness of the coatings, which are composed of Ta_(2)O_(5),(Ta, O), and TaO. A thick and hard coating is obtained in the NaF-containing electrolyte, and the tribology performance is effectively improved. With additives, the nodule structure is detached from the coating surface and dissolved in the electrolyte. By using NaF as an electrolyte additive, the abrasion performance of the MAO coating is enhanced by decreasing the nodule structure, increasing the size of micropores, and improving the coating hardness.

关键词： micro-arc oxidation tantalum alloy additives tribology performance

Cnoidal waves and their soliton limits in single mode fiber lasers

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2024年第3期12卷 543-551页

作者： XIAO hu TUPEI CHEN SEONGWOO YOO DINGYUAN TANG Julong College Shenzhen Technology UniversityShenzhen 518118China School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore 639798Singapore

Cnoidal waves are a type of nonlinear periodic wave solutions of the nonlinear dynamic *** are well known in fluid dynamics,but it is not the case in *** this paper we show both experimentally and numerically that cnoidal waves could be formed in a fiber laser either in the net normal or net anomalous cavity dispersion regime,especially because,as the pump power is increased,the formed cnoidal waves could eventually evolve into a train of bright(in the net anomalous cavity dispersion regime)or dark(in the net normal cavity dispersion regime)*** simulations of the laser operation based on the extended nonlinear Schrödinger equation(NLSE)have well reproduced the experimental *** result not only explains why solitons can still be formed in a fiber laser even without mode locking but also suggests a new effective way of automatic stable periodic pulse train generation in lasers with a nonlinear cavity.

关键词： fiber pump mode

Microstructure and mechanical properties stability of pre-hardening treatment in Al-Cu alloys for pre-hardening forming process

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 539-551页

作者： Liping Tang Pengfei Wei Zhili hu Qiu Pang hubei Longzhong laboratory Xiangyang 441000China hubei Key Laboratory of Advanced Technology for Automotive Components School of Automotive EngineeringWuhan University of TechnologyWuhan 430070China hubei Engineering Research Center for Green&Precision Material Forming Wuhan University of TechnologyWuhan 430070China Key Laboratory of Metallurgical Equipment and Control Technology of Ministry of Education School of Machinery and AutomationWuhan University of Science and TechnologyWuhan 430081China

The stability of the microstructure and mechanical properties of the pre-hardened sheets during the pre-hardening forming(PHF)process directly determines the quality of the formed *** microstructure stability of the pre-hardened sheets was in-vestigated by differential scanning calorimetry(DSC),transmission electron microscopy(TEM),and small angle X-ray scattering(SAXS),while the mechanical properties and formability were analyzed through uniaxial tensile tests and formability *** results in-dicate that the mechanical properties of the pre-hardened alloys exhibited negligible changes after experiencing 1-month natural aging(NA).The deviations of ultimate tensile strength(UTS),yield strength(YS),and sheet formability(Erichsen value)are all less than 2%.Also,after different NA time(from 48 h to 1 month)is applied to alloys before pre-hardening treatment,the pre-hardened alloys possess stable microstructure and mechanical properties as ***,with the extension of NA time before pre-hardening treatment from 48 h to 1 month,the contribution of NA to the pre-hardening treatment is *** a yield strength increment of 20 MPa is achieved,with no loss in *** limited enhancement is mainly attributed to the fact that only a limited number of clusters are transformed into Guinier-Preston(GP)zones at the early stage of pre-hardening treatment,and the formation ofθ''phase inhibits the nucleation and growth of GP zones as the precipitated phase evolves.

关键词： Al-Cu alloy pre-hardened alloy natural aging mechanical properties microstructure

An improved interval model updating method via adaptive Kriging models

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 497-514页

作者： Sha WEI Yifeng CHEN hu DING Liqun CHEN Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechanoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China Shanghai Institute of Aircraft Mechanics and Control Shanghai 200092China

Interval model updating(IMU)methods have been widely used in uncertain model updating due to their low requirements for sample ***,the surrogate model in IMU methods mostly adopts the one-time construction *** makes the accuracy of the surrogate model highly dependent on the experience of users and affects the accuracy of IMU ***,an improved IMU method via the adaptive Kriging models is *** method transforms the objective function of the IMU problem into two deterministic global optimization problems about the upper bound and the interval diameter through universal grey *** optimization problems are addressed through the adaptive Kriging models and the particle swarm optimization(PSO)method to quantify the uncertain parameters,and the IMU is *** the construction of these adaptive Kriging models,the sample space is gridded according to sensitivity *** sampling is then performed in key subspaces based on the maximum mean square error(MMSE)*** interval division coefficient and random sampling coefficient are adaptively adjusted without human interference until the model meets accuracy *** effectiveness of the proposed method is demonstrated by a numerical example of a three-degree-of-freedom mass-spring system and an experimental example of a butted cylindrical *** results show that the updated results of the interval model are in good agreement with the experimental results.

关键词： interval model updating(IMU) non-probabilistic uncertainty adaptive Kriging model surrogate model grey number

pH- and near-infrared light-responsive,biomimetic hydrogels from aqueous dispersions of carbon nanotubes

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第4期17卷 3120-3129页

作者： Lulin hu Xinxin Yu Jingcheng Hao Lu Xu Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 264000China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Yantai Center for Food and Drug Control Yantai 264000China Key Laboratory of Colloid and Interface Chemistry&Key Laboratory of Special Aggregated Materials Shandong UniversityJinan 250100China

Owing to their low flexibility,poor processability and a lack of responsiveness,inorganic materials are usually non-ideal for constructing a living ***,to date,lifelike materials with structural hierarchies and adaptive properties usually rely on light and soft organic molecules,although few exceptions have been acquired using two-dimensional(2D)inorganic ***,with a systematic study on the gelation behavior of carbon-based 0D quantum dots,1D nanotubes,and 3D fullerenes,we find that acidified 1D carbon nanotubes(CNTs)can serve as an alternative building block for fabricating purely inorganic biomimetic soft *** as-prepared CNT gels exhibit not only a pH-or photothermal-triggered mechanical and tribological adaptivity,which allows them to simulate the behavior of sea cucumbers,peacock mantis shrimps,and mammalian muscles or cortical bones,but also a unique damping property that is similar to spider’s cuticular *** high elasticity,effective lubrication,excellent biocompatibility,and controllable friction and wear also allow them to function as a new type of smart lubricants,whose tribological properties can be regulated either by its internal pH changes or spatiotemporally by near-infrared(NIR)light irradiations,free of any toxic and flammable base oils or additives.

关键词： biomimetic hydrogels carbon nanotubes(CNTs) mechanical and tribological adaptivity pH-and near-infrared(NIR)light responsiveness switchable lubrication

Feedback Mechanism-driven Mutation Reptile Search Algorithm for Optimizing Interpolation Developable Surfaces

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

Journal of Bionic Engineering 2024年第1期21卷 527-571页

作者： Gang hu Jiao Wang Xiaoni Zhu Muhammad Abbas Department of Applied Mathematics Xi'an University of TechnologyXi'an 710054China School of Mechanical and Precision Instrument Engineering Xi'an University of TechnologyXi'an 710048China Department of Mathematics University of SargodhaSargodha 40100Pakistan

Curvature lines are special and important curves on *** is of great significance to construct developable surface interpolated on curvature lines in engineering *** this paper,the shape optimization of generalized cubic ball developable surface interpolated on the curvature line is studied by using the improved reptile search ***,based on the curvature line of generalized cubic ball curve with shape adjustable,this paper gives the construction method of SGC-Ball developable surface interpolated on the ***,the feedback mechanism,adaptive parameters and mutation strategy are introduced into the reptile search algorithm,and the Feedback mechanism-driven improved reptile search algorithm effectively improves the solving *** IEEE congress on evolutionary computation 2014,2017,2019 and four engineering design problems,the feedback mechanism-driven improved reptile search algorithm is compared with other representative methods,and the result indicates that the solution performance of the feedback mechanism-driven improved reptile search algorithm is *** last,taking the minimum energy as the evaluation index,the shape optimization model of SGC-Ball interpolation developable surface is *** developable surface with the minimum energy is achieved with the help of the feedback mechanism-driven improved reptile search algorithm,and the comparison experiment verifies the superiority of the feedback mechanism-driven improved reptile search algorithm for the shape optimization problem.

关键词： Reptile search algorithm Feedback mechanism Adaptive parameter Mutation strategy SGC-Ball interpolation developable surface Shape optimization

Stochastic LQ Control with Extra Measurability Restriction

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

Journal of Systems Science & Complexity 2024年第3期37卷 1003-1022页

作者： WANG Hongxia hu Yuxi LI Zixing SONG Lianfeng College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266590China

Different from the standard linear quadratic(LQ)problem for stochastic systems,the LQ problem considered in the paper has extra measurability *** problem also appears in the LQ control problem for stochastic systems with delays,rational expectations problems,asymmetric information control,and so *** essential difficulty lies in that one has to optimize the input and its conditional expectations *** stochastic maximum principle(SMP)and orthogonal decomposition technique are the key ***,the authors establish the SMP and convert the original problem into forward and backward stochastic difference equations(FBSDEs)with extra measurability ***,the authors resolve the FBSDEs by using the orthogonal decomposition technique and obtain the analytical solution to the underlying ***,the authors explore the essential distinction between the problem and the standard stochastic LQ control ***,numerical examples are given to illustrate the obtained results.

关键词： Multiplicative noise systems optimal control stochastic maximum principle stochastic systems

A review of medical ocular image segmentation

在线全文

学校读者我要写书评

暂无评论

虚拟现实与智能硬件（中英文） 2024年第3期6卷 181-202页

作者： Lai WEI Menghan hu Shanghai Key Laboratory of Multidimensional Information Processing East China Normal UniversityShanghai 200241China

Deep learning has been extensively applied to medical image segmentation,resulting in significant advancements in the field of deep neural networks for medical image segmentation since the notable success of U Net in ***,the application of deep learning models to ocular medical image segmentation poses unique challenges,especially compared to other body parts,due to the complexity,small size,and blurriness of such images,coupled with the scarcity of *** article aims to provide a comprehensive review of medical image segmentation from two perspectives:the development of deep network structures and the application of segmentation in ocular ***,the article introduces an overview of medical imaging,data processing,and performance evaluation ***,it analyzes recent developments in U-Net-based network ***,for the segmentation of ocular medical images,the application of deep learning is reviewed and categorized by the type of ocular tissue.

关键词： Medical image segmentation Orbit Tumor U-Net Transformer

Underwater Directional Acoustic Source Based on Pentamode Material

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2024年第1期37卷 1-9页

作者： Binghao Zhao Peng Wang Dongwei Wang Gengkai hu School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Wuhan Second Ship Design and Research Institute Wuhan 430205China

An underwater directional acoustic emitter is conceived with a highly anisotropic lattice material,whose acoustic characteristics manifest strong dependence on the orientation of the lattice material’s principal *** these features,a cylindrical structure made of such anisotropic lattice material is engineered to possess distinct impedance values in different directions,thereby facilitating wave emission along the principal axis while inducing reflection in other ***,through numerical simulations,it is demonstrated that the emission direction can be effectively manipulated by adjusting the principal axis orientation,concurrently enhancing the emitted *** contrast to previous directional acoustic structures,the compact emitter presented in this study can get rid of the size-wavelength constraint,enabling effective control of low-frequency waves.

关键词： Underwater Directional emission Pentamode material Broadband frequency