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PREPARATION OF NANOSIZED SILICON NITRIDE POWDERS BY AMMONO SOL-GEL PROCESSING

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中国有色金属学会会刊：英文版 1997年第3期7卷 22-25页

作者： Gao, jiming Xiao, Hanning Zhang, Li Du, Haiqing Hunan Univ Changsha China

ＰＲＥＰＡＲＡＴＩＯＮＯＦＮＡＮＯＳＩＺＥＤＳＩＬＩＣＯＮＮＩＴＲＩＤＥＰＯＷＤＥＲＳＢＹＡＭＭＯＮＯＳＯＬＧＥＬＰＲＯＣＥＳＳＩＮＧ①ＧａｏＪｉｍｉｎｇ，ＸｉａｏＨａｎｎｉｎｇ，ＺｈａｎｇＬｉ，ＤｕＨａｉｑｉｎｇ... 详细信息

ＰＲＥＰＡＲＡＴＩＯＮＯＦＮＡＮＯＳＩＺＥＤＳＩＬＩＣＯＮＮＩＴＲＩＤＥＰＯＷＤＥＲＳＢＹＡＭＭＯＮＯＳＯＬＧＥＬＰＲＯＣＥＳＳＩＮＧ①ＧａｏＪｉｍｉｎｇ，ＸｉａｏＨａｎｎｉｎｇ，ＺｈａｎｇＬｉ，ＤｕＨａｉｑｉｎｇＣｈｅｍｉｓｔｒｙａｎｄＣｈｅｍｉ...

关键词： silicon nitride nanosized powder ammonolysis sol gel

Preparation and Characterization of Ni60-Cr_3C_2-WC/TiC Plasma Welding Surfacing Layer

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Journal of Wuhan University of Technology(Materials Science) 2018年第6期33卷 1402-1406页

作者： ZHU jiming YU Hailing Department of Resources and Civil Engineering Shandong University of Science and Technology College of Mining and Safety Engineering Shandong University of Science and Technology

Using plasma build-up welding technology, Ni60, WC, Cr3C2, and TiC composite powders were clad on the surface of the substrate in a certain proportion according to the metallurgical bonding method to increase the bond strength between the coating and the substrate. Scanning electron microscopy and energy dispersive spectroscopy were used to observe the microstructure of the surfacing layer and the chemical composition of the sample. The hardness and wear resistance of the surfacing layer were tested and analyzed by the HV-1000 hardness tester and the impact wear device. The results showed that in the microstructure, fishbone, spider-web, and floral-like structures appeared in the surfacing layer. When the micro-hardness was tested, the depth of the indentation reflected the hardness of the surfacing layer. When analyzing wear resistance, the amount of wear increases with time.

关键词： Ni60 Cr3C2 WC/TiC plasma surfacing layer

含孔洞CoCrNiFeCu高熵合金纳米压入的分子动力学模拟

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原子与分子物理学报 2025年第3期42卷 141-148页

作者：史银花施琴江苏联合职业技术学院镇江分院镇江212016

高熵合金具有优异的力学性能、耐磨耐蚀耐高温等性能,成为未来最有发展潜力的新型材料之一.因此,本文通过分子动力学模拟的方法探究了孔洞对CoCrNiFeCu高熵合金模型纳米压痕力学性能和位错演化的影响.结果表明,屈服点、载荷、杨氏模量... 详细信息

高熵合金具有优异的力学性能、耐磨耐蚀耐高温等性能,成为未来最有发展潜力的新型材料之一.因此,本文通过分子动力学模拟的方法探究了孔洞对CoCrNiFeCu高熵合金模型纳米压痕力学性能和位错演化的影响.结果表明,屈服点、载荷、杨氏模量和硬度等力学参数随着孔洞深度D的增加呈现先增加后稳定的趋势.孔洞的存在显著影响了位错形核的位置,随着孔洞深度的增加,初始位错优先在孔洞与表面之间形成,随后集中在模型表面形成,且位错环由平面圆环状转变为“翼状”.在孔洞深度较小时(D<40A),位错环沿(110)面水平扩展,随着孔洞深度的增加,位错环开始向下扩展.此外,在压痕深度为30?时,位错密度随着孔洞深度的增加逐渐增加.

关键词： CoCrNiFeCu 分子动力学纳米压入力学性能位错演变

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Insight into the triggering effect of(Al,Mg,Ca,Mn)-oxy-sulfide inclusions on localized corrosion of weathering steel

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Journal of Materials Science & Technology 2021年第5期64卷 99-113页

作者： Pan Liu Qinhao Zhang Xinran Li jiming Hu Fahe Cao Department of Chemistry Zhejiang UniversityHangzhou310027China School of Materials Sun Yat-sen UniversityGuangzhou510006China

The surface properties of weathering steel(WS)is very important for its service performance and safety,and the localized corrosion induced by inclusions is closely related to the surface properties of WS and its *** the current work,a common spherical(Al,Mg,Ca,Mn)-oxy-sulfide inclusion was selected to investigate the corrosion evolution of complex inclusion and its effect on localized corrosion on WS *** results indicate the inclusion in WS consists of(Ca,Mn)sulfides part and(Ca,Al,Mg)oxides part with complex core-shell *** preferential dissolution occurs in(Ca,Mn)sulfides part as well as metal matrix around the ***,both parts of the inclusions with poor conductivity and high-density dislocation at metal matrix around the inclusions was found,which suggests that traditional micro-galvanic corrosion cell may not be the cause of inclusion-induced localized corrosion on WS surface at initial stage of *** variation in maximum and average depth around the inclusion or selected region with immersion time indicates that localized corrosion induced by inclusions is overwhelmed by uniform corrosion of WS in the latter stage of immersion,then the rust formed on WS surface consists of two layers.

关键词： Weathering steel Inclusions Marine environment Localized corrosion Rust

The weeping characteristic of submerged multi-orifice plate

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Chinese Journal of Chemical Engineering 2020年第4期28卷 955-968页

作者： jiming Wen Ruifeng Tian Sichao Tan Qiunan Sun Haifeng Gu Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering UniversityHarbin 150001China

Weeping is an adverse phenomenon which results in higher pressure drop and poorer aeration *** experiments have been conducted to study the mechanism by which weeping impairs the work performance of multi-orifice plate.A theoretical model is improved to analyze the weeping phenomenon of multiorifice plate based on potential flow *** relations of different bubbling conditions and weeping rate are *** condition and average weeping rate have relation with the driven pressure differential and dynamic variation of gas chamber *** addition,a set of experiments are designed to study the influence of various factors on weeping *** bubble coalescence during bubble formation is a fatal factor determining weeping rate,so the relation between weeping rate and gas flow rate is concerned with the pitch of orifices and orifice *** is a critical plate thickness which is in favor of weeping.

关键词： Weeping Multi-orifice plate Wave pressure Gas chamber pressure

Distillation Sequence Optimization Considering Extractive Distillation under Multiple Conditions: A Methanol to Propylene Case Study

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China Petroleum Processing & Petrochemical Technology 2019年第4期21卷 88-93页

作者： Yu Jing Qian Feng Wang jiming Key Laboratory of Advanced Control and Optimization for Chemical Process Ministry of EducationEast China University of Science and TechnologyShanghai 200237 Coteva AgriscienceTM Shanghai 201203 School of Chemical Engineering East China University of Science and TechnologyShanghai 200237

This study provides insights into the distillation sequence optimization of refinery system in a methanol to propylene plant with extractive distillation under multiple conditions. The simulated annealing algorithm(SA) with relative cost function was used to solve a meaningful optimization problem. It was observed that different conditions had differed on the flowsheet. Case study shows the effectiveness of the proposed method.

关键词： distillation sequence optimization simulated annealing algorithm MATLAB multiple conditions

Assessment of tomographic window and sampling rate efects on GNSS water vapor tomography

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Satellite Navigation 2023年第1期4卷 155-166,I0005页

作者： Fei Yang Yilin Sun Xiaolin Meng jiming Guo Xu Gong College of Geoscience and Surveying Engineering China University of Mining and Technology-BeijingBeijing 100083China College of Architecture and Civil Engineering Beijing University of TechnologyBeijing 100124China School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China

The ground-based Global Navigation Satellite System(GNSS)water vapor tomography is increasingly important in GNSS *** the multi-GNSS and more ground-based GNSS sites can be incorporated into the regional water vapor tomographic model,determining the tomographic window and sampling rate is crucial for the modelling of the water vapor *** two factors afect not only the number of available signal rays from the satellites,but also the number of tomographic voxels crossed by the signal *** study uses Hong Kong as the research area to explore the impact of 12 schemes with diferent tomographic window and sampling rate on the three water vapor tomography methods,including Least squares,Kalman fltering,and Multiplicative Algebraic Reconstruction Technique(MART).Numerical results show that the tomographic results with the three methods get better as the width of the tomographic window decreases and the sampling rate increases in these 12 schemes,and it is found that the Least squares method is most afected by the two factors,followed by Kalman fltering and MART *** is recommended to set a tomographic window width of 10 min and a sampling rate of 300 s in a GNSS water vapor tomographic experiment with dense GNSS site like Hong Kong.

关键词： GNSS meteorology Water vapor Tomography

Trends of chemical speciation profiles of anthropogenic volatile organic compounds emissions in China, 2005-2020

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Frontiers of Environmental Science & Engineering 2014年第1期8卷 27-41页

作者： Wei WEI Shuxiao WANG jiming HAO Shuiyuan CHENG Department of Environmental Science and Engineering Beijing University of Technology Beijing 100124 China School of Environment State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC) Tsinghua University Beijing 100084 China

This study estimates the detailed chemical profiles of China＇s anthropogenic volatile organic com- pounds （VOCs） emissions for the period of 2005-2020. The chemical profiles of VOCs for seven activity sectors are calculated, based on which the Photochemical Ozone Creation Potential （POCP） of VOCs for these sectors is evaluated. At the national level, the VOCs species emitted in 2005 include alkanes, alkenes and alkynes, aromatic compounds, alcohols, ketones, aldehydes, esters, ethers and halocarbons, accounting for 26.4wt.%, 29.2wt.%, 21.3 wt.%, 4.7 wt.%, 5.4 wt.%, 1.7 wt.%, 2.1 wt.%, 0.7 wt. % and 2.2wt.% of total emissions, respectively. And during 2005-2020, their mass proportions would respec- tively grow or decrease by - 34.7%, -48.6%, 108.5%, 6.9%, -32.7%, 7.3%, 65.3%, 100.5%, and 55.4%. This change would bring about a 13% reduction of POCP for national VOCs emissions in the future. Thus, although the national VOCs emissions are expected to increase by 33% over the whole period, its ozone formation potential is estimated to rise only by 14%. Large discrepancies are found in VOCs speciation emissions among provinces. Compared to western provinces, the eastern provinces with a more developed economy would emit unsaturated hydrocarbons and benzene with lower mix ratios, and aromatic compounds except benzene, oxidized hydrocar- bons and halocarbons with higher mix ratios. Such differences lead to lower POCP of VOCs emitted in eastern provinces, and higher POCP of VOCs emitted in western provinces. However, due to the large VOCs emissions from Chinese eastern region, the ozone forma- tion potential of VOCs emission in eastern provinces would be much higher than those in western provinces by about 156%-235%.

关键词： volatile organic compounds (VOCs) chemi-cal speciation ozone formation Photochemical OzoneCreation Potential (POCP) China

An Interpolation-Free Cell-Centered Finite Volume Scheme for 3D Anisotropic Convection-Diffusion Equations on Arbitrary Polyhedral Meshes

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Communications in Computational Physics 2023年第10期34卷 1277-1305页

作者： Shuai Miao jiming Wu Yanzhong Yao School of Mathematical Sciences Peking UniversityBeijing100871P.R.China Institute of Applied Physics and Computational Mathematics Beijing100088P.R.China

Most existing cell-centered finite volume schemes need to introduce auxiliary unknowns in order to maintain the second-order accuracy when the mesh is distorted or the problem is discontinuous,so interpolation algorithms of auxiliary unknowns are *** algorithms are not only difficult to construct,but also bring extra *** this paper,an interpolation-free cell-centered finite volume scheme is proposed for the heterogeneous and anisotropic convectiondiffusion problems on arbitrary polyhedral *** propose a new interpolationfree discretization method for diffusion term,and two new second-order upwind algorithms for convection *** interestingly,the scheme can be adapted to any mesh topology and can handle any discontinuity *** experiments show that this new scheme is robust,possesses a small stencil,and has approximately secondorder accuracy for both diffusion-dominated and convection-dominated problems.

关键词： Interpolation-free finite volume scheme convection-diffusion polyhedral mesh