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Effect of high magnetic field on the crystallization of Nd_2Fe_(14)B/α-Fe nanocomposite magnets

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Rare Metals 2006年第4期25卷 337-341页

作者： WANG Zhanyong XU Hui ni Jiansen LI Qiang zhou Bangxin Institute of Materials Science Shanghai University Shanghai 200072 China Department of Materials Engineering Shanghai Institute of Technology Shanghai 200235 China Center of Test and Measurement Shanghai University Shanghai 200436 China

Nd8.1Dy0.9Fe76.95Co8.55B5.5 nanocomposite magnets annealed with and without a 10 T magnetic field were investigated in this article. The ribbons with coexisting amorphous and crystalline phases were selected to do this study. The resuits of Moessbauer spectroscopy revealed that the content of α--Fe increased when annealed in high strength magnetic field. The size of the grains also increased considerably after the application of magnetic annealing. All these led to the decrease of the magnetic properties, especially the coercivity of the ribbons.

关键词： magnetic materials nanocomposite magnet crystallization magnetic field melt spinning

The revival of thermal utilization from the Sun: interfacial solar vapor generation

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National Science Review 2019年第3期6卷 562-578页

作者： Lin zhou Xiuqiang Li George W.ni Shining Zhu Jia Zhu National Laboratory of Solid State Microstructures College of Engineering and Applied Sciences School of Physics Key Laboratory of Intelligent Optical Sensing and Manipulation Ministry of Education Collaborative Innovation Center of Advanced Microstructures Nanjing University Department of Mechanical Engineering Massachusetts Institute of Technology

Since solar energy is the ultimate energy resource and a significant amount of global energy utilization goes through heat, there have been persistent efforts for centuries to develop devices and systems for solar–thermal conversion. Most recently, interfacial solar vapor generation, as an emerging concept of solar–thermal conversion, has gained significant attention for its great potentials in various fields such as desalination, sterilization, catalysis, etc. With the advances of rationally designed materials and structures and photon and thermal management at the nanoscale, interfacial solar vapor generation has demonstrated both thermodynamic and kinetical advantages over conventional strategies. In this review, we aim to illustrate the definition, mechanism and figures of merit of interfacial solar vapor generation, and to summarize the development progress of relevant materials and applications, as well as to provide a prospective view of the future.

关键词： solar vapor generation solar absorber solar evaporator interfacial heating

Multi-Function Uninterrupted Phase-Separation Passing System and its Control Method

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CSEE Journal of Power and Energy Systems 2023年第6期9卷 2332-2343页

作者： zhou ni Jiaxin Yuan Feiran Xiao Liwen Peng Zhaoyang Zhang Yongzhi Min the School of Electrical Engineering and Automation Wuhan UniversityWuhan 430072China the School of Electrical Engineering Naval University of EngineeringWuhan 430030China the State Grid Jinan Power Supply Company Jinan 250061China the Department of Electrical and Electronic Engineering Lanzhou Jiaotong UniversityLanzhou 730070China

At present, sudden load changes and terminal voltage fluctuations are two primary problems in the uninterrupted phase-separation passing (UPP) system. To further enhance the reliability of the UPP system and compensate for the voltage sag at the end of the traction power supply network caused by the suddenly connection of locomotive to the power grid, a multi-function uninterrupted phase-separation passing system (MUPPS) and its control strategy are proposed. It has the advantages of linear load change and improving power supply reliability. First, the topology and working principles of a MUPPS are studied;secondly, the current variation characteristics of the bridge arm when the power is continuously supplied by MUPPS during the phase-separation passing are analyzed. Then, the characteristics of a MUPPS to provide reactive power and stabilize the terminal voltage of the traction arm are analyzed. Then, the power transmission characteristics of a MUPPS under emergency working conditions are analyzed. The control strategy for the two conditions is proposed. Finally, simulation analysis and small capacity experiments are conducted. The theoretical analysis and test confirm the correctness and effectiveness of the MUPPS.

关键词： Control strategy high-speed railway MUPPS neutral section

Framework on low-carbon retrofit of rural residential buildings in arid areas of northwest China:A case study of Turpan residential buildings

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Building Simulation 2023年第2期16卷 279-297页

作者： Junkang Song Wanjiang Wang Pingan ni Hanjie Zheng Zihan Zhang Yihuan zhou College of Architectural and Civil Engineering Xinjiang University830017China College of Architecture Xi'an University of Architecture and Technology710000China College of Architecture and Environment Sichuan University610065China

At present,buildings in arid and hot regions are facing severe challenges of indoor comfort improvement and carbon emission reduction,especially in rural ***-objective optimization could be an effective tool for tackling the aforementioned ***,this paper proposes a life-cycle optimization framework considering thermal comfort,which is beneficial to promoting residents’motivation for low-carbon retrofit in arid climate ***,in response to the above problems,three objective functions are specified in the framework,which are global warming potential(GWP),life cycle cost(LCC),and thermal discomfort hours(TDH).To improve the optimization efficiency,this research uses Deep Neural Networks(DNN)combined with NSGA-II to construct a high-precision prediction model(meta-model for optimization)based on the energy consumption simulation database formed by the orthogonal multi-dimensional design *** accuracy index of the modified model is R2>0.99,cv(RMSE)≤1%,and NMBE≤0.2%,which gets rid of the dilemma of low prediction accuracy of traditional machine learning *** the scheme comparison and selection stage,the TOPSIS based on two empowerment methods is applied to meet different design tendencies,where the entropy-based method can avoid the interference of subjective preference and significantly improve the objectivity and scientific nature of decision ***,sensitivity analysis is conducted on the variables,which supports guidance for practitioners to carry out the low-carbon ***,the multi-objective optimization analysis for a farmhouse in Turpan is taken as a case study to evaluate the performance of the *** results show that the framework could significantly improve the building performance,with 60.8%,52.5%,and 14.2%reduction in GWP,LCC,and TDH,respectively.

关键词： life cycle assessment arid regions deep neural networks entropy-based TOPSIS method multi-criteria optimization

New insight into the stability and dynamics of fluid-conveying supported pipes with small geometric imperfections

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Applied Mathematics and Mechanics(English Edition) 2021年第5期42卷 703-720页

作者： Kun zhou Qiao ni Wei CHEN Huliang DAI Zerui PENG Lin WANG Department of Mechanics School of Aerospace EngineeringHuazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment Wuhan 430074China Department of Mechanical Engineering Technische Universitat DarmstadtDarmstadt 64293Germany

In several previous studies,it was reported that a supported pipe with small geometric imperfections would lose stability when the internal flow velocity became sufficiently ***,however,it has become clear that this conclusion may be at best incomplete.A reevaluation of the problem is undertaken here by essentially considering the flow-induced static deformation of a *** the aid of the absolute nodal coordinate formulation(ANCF)and the extended Lagrange equations for dynamical systems containing non-material volumes,the nonlinear governing equations of a pipe with three different geometric imperfections are introduced and *** on extensive numerical calculations,the static equilibrium configuration,the stability,and the nonlinear dynamics of the considered pipe system are determined and *** results show that for a supported pipe with the geometric imperfection of a half sinusoidal wave,the dynamical system could not lose stability even if the flow velocity reaches an extremely high value of ***,for a supported pipe with the geometric imperfection of one or one and a half sinusoidal waves,the first-mode buckling instability would take place at high flow ***,based on a further parametric analysis,the effects of the amplitude of the geometric imperfection and the aspect ratio of the pipe on the static deformation,the critical flow velocity for buckling instability,and the nonlinear responses of the supported pipes with geometric imperfections are analyzed.

关键词： supported pipes conveying fluid geometric imperfection absolute nodal coordinate formulation(ANCF) static equilibrium configuration critical flow velocity nonlinear dynamics

Research on the method of construction disturbance zoning for shield tunnel approaching to urban structures

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Frontiers of Structural and Civil Engineering 2024年第11期18卷 1663-1679页

作者： Ziyang zhou Fukang GUO Jianzhong ni Kun FENG Jingxuan ZHANG Yiwen LIU Key Laboratory of Transportation Tunnel Engineering of Ministry of Education Southwest Jiaotong UniversityChengdu 610031China Hangzhou Fuyang City Construction Investment Group co. Ltd.Hangzhou 310000China

This paper presents a calculation method that evaluates the extent of disturbance based on structural safety ***,it summarizes the assessment methods for construction disturbance zones in shield tunneling near pile foundations,urban ground structures,and underground ***,taking the construction of the Chengdu Jinxiu Tunnel under bridges and urban pipelines as the engineering background,a study on the disturbance zoning of adjacent structures was *** most intense disturbance occurs within one week of the tunnel underpass process,and it has a significant impact within a range of two times the tunnel diameter along the tunnel *** bridge pile and bridge deck experience less disturbance from tunnel approaching construction,with a maximum disturbance zone characterized as medium *** the other hand,underground pipelines are subjected to more significant disturbances from tunnel construction,with a maximum disturbance zone classified as strong *** implementation of“bridge pile sleeve valve pipe grouting&underground pipeline ground grouting&tunnel advance grouting”in the field effectively limits the vertical settlement of bridges and pipelines,resulting in a decrease of approximately 0.1 in disturbance level for the *** disturbance zoning method can assess tunnel disturbance with structures,identify high-risk interference locations,and facilitate targeted design reinforcement solutions.

关键词： shield tunnel approaching construction field monitoring disturbance zoning method

Research on the Marine Antifouling Ability and Mechanism of Acrylate Copolymers and Marine Coatings Based on a Synergistic Effect

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Journal of Ocean University of China 2023年第3期22卷 717-727页

作者： zhou Wenjun zhou Yu ni Chunhua YU Liangmin YUAN Zhengjun LI Changcheng YAN Xuefeng Key Laboratory of Marine Chemistry Theory and Technology Ministry of EducationOcean University of ChinaQingdao 266100China Sanya Oceanographic Institution Ocean University of ChinaSanya 572024China

Marine biofouling is an urgent global problem in the process of ocean exploitation and *** our work,a series of zinc-based acrylate copolymers(ACZn-x)were designed and synthesized using benzoic acid,zinc oxide(ZnO)and a random quaternion copolymer consisting of ethyl acrylate(EA),butyl acrylate(BA),acrylic acid(AA)and methacrylic acid(MAA)by free radical polymerization and dehydration *** ACZn-x with a zinc benzoate side chain is able to hydrolyze in natural seawater under static conditions,resulting in the formation of a smooth *** investigated and confirmed the antifouling(AF)behavior of ACZn-x in the laboratory and revealed that they have better antibacterial(86%for *** and 72%for ***)and anti-algal(≥60.1%for *** and≥67.5%for ***)*** also assessed the marine AF properties of ACZn-x and corresponding coatings in Qingdao,China;the ACZn-x exhibited ideal AF properties with little silt and biological mucosa adhered to the ACZn-x surface after 6 months,and corresponding coatings exhibited little biofouling after 16 months in the ***,possible AF mechanisms were further proposed at the cellular *** results could be helpful for the development and application of effective AF coatings.

关键词： zinc-based acrylate copolymer self-polishing marine antifouling mechanism

Comparative analysis of modern and ancient buried Phoebe zhennan wood:surface color,chemical components,infrared spectroscopy,and essential oil composition

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Journal of Forestry Research 2015年第2期26卷 501-507页

作者： Jiulong Xie Jinqiu Qi Xingyan Huang ni zhou Yao Hu College of Forestry Sichuan Agricultural University

We compared the chemical components and essential oils of ancient buried Zhennan（Phoebe zhennan）wood with those in samples from living *** removal of the carbon layer the recovered Zhennan exhibited a dark green color,which differed from the yellow color of the living *** molecular weight components（including hot-water and toluene-alcohol extractives）,hemicellulose,and 1 % Na OH solubility in the recovered wood were greatly *** of cellulose was ***,the ancient wood had somewhat more klason lignin than the modern *** transform infrared（FTIR） analysis gave further evidence on the differences in chemical *** to the GC–MS results,naphthalene derivatives were detected in the essential oils from both the modern and recovered *** delicate fragrance of the modern and recovered wood may be attributed to the aromatic constituents as identified by GC–MS.

关键词： Phoebe zhennan Ancient buried wood Chemistry Essential oil

DFT Calculations for Electron Transfer Bond-breakingReaction of CH_3-X

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Chinese Chemical Letters 2001年第4期12卷 347-350页

作者： Yu Mei XING Zheng Yu zhou Ben ni DU Department of Chemistry Qufu Normal UniversityShandong Qufu 273165 Department of Chemistry Nankai UniversityTianjin 300071 State Key Laboratory of Crystal Materials Shandong UniversityShandongJinan 250100

DFT/6-311 + g** level calculations are performed tp study the electron transfer bond-breaking reaction of CH3-X. The calculated values are in good agreement with the experimental results or the empirical model. Through analyzing the change of the energy and the charge densilty along hte reaction path, the bond-breaking in ET reaction for CH3X is investigated.

关键词： electron transfer bond-breaking reaction density functional theory (DFT) CH_(3)X