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Quasi Ellipsoid Gear Surface Reconstruction Based on Meshless Local Petrov-Galerkin Method and Transmission Characteristic

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Chinese Journal of Mechanical Engineering 2010年第6期23卷 788-792页

作者： wu xuemei SHAN Debin LI Guixian School of Mechanical and Electrical Engineering Harbin Institute of Technology Harbin 150006 China School of Materials Science and Engineering Harbin Institute of Technology Harbin 150006 China

Special transmission 3D model simulation must be based on surface discretization and reconstruction, but special transmission usually has complicated tooth shape and movement, so present software can＇t provide technical support for special transmission 3D model simulation. Currently, theoretical calculation and experimental method are difficult to exactly solve special transmission contact analysis problem. How to reduce calculation and computer memories consume and meet calculation precision is key to resolve special transmission contact analysis problem. According to 3D model simulation and surface reconstruction of quasi ellipsoid gear is difficulty, this paper employes meshless local Petrov-Galerkin （MLPG） method. In order to reduce calculation and computer memories consume, we disperse tooth mesh into finite points--sparseness points cloud or grid mesh, and then we do interpolation reconstruction in some necessary place of the 3D surface model during analysis. Moving least square method （MLSM） is employed for tooth mesh interpolation reconstruction, there are some advantages to do interpolation by means of MLSM, such as high precision, good flexibility and no require of tooth mesh discretization into units. We input the quasi ellipsoid gear reconstruction model into simulation software, we complete tooth meshing simulation. Simulation transmission ratio during meshing period was obtained, compared with theoretical transmission ratio, the result inosculate preferably. The method using curve reconstruction realizes surface reconstruction, reduce simulation calculation enormously, so special gears simulation can be realized by minitype computer. The method provides a novel solution for special transmission 3D model simulation analysis and contact analysis.

关键词： meshless local Petrov-Galerkin method moving least square method quasi ellipsoid gear tooth mesh simulation

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Effect of Low-Frequency Power on Etching Characteristics of 6H-SiC in C4F8/Ar Dual-Frequency Capacitively Coupled Plasma

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Plasma Science and Technology 2013年第10期15卷 1066-1070页

作者： XU Yijun wu xuemei YE Chao Department of Physics Soochow University Suzhou 215006 China The Key Laboratory of Thin Films of Jiangsu Soochow University Suzhou 215006 China State Key Laboratory of Functional Materials for Informatics Shanghai Institute ofMicrosystem and Information Technology Chinese Academy of Sciences Shanghai 200050China

Dry etching of 6H silicon carbide （6H-SiC） wafers in a C4Fs/Ar dual-frequency capacitively coupled plasma （DF-CCP） was investigated. Atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS） were used to measure the SiC surface structure and compositions, respectively. Optical emission spectroscopy （OES） was used to measure the relative concentration of F radicals in the plasma. It was found that the roughness of the etched SiC surface and the etching rate are directly related to the power of low-frequency （LF） source. At lower LF power, a smaller surface roughness and a lower etching rate are obtained due to weak bombardment of low energy ions on the SiC wafers. At higher LF power the etching rate can be efficiently increased, but the surface roughness increases too. Compared with other plasma dry etching methods, the DF-CCP can effectively inhibit CχFγ films＇ deposition, and reduce surface residues.

关键词： SiC plasma etching dual-frequency capacitively coupled plasma X-ray photoelectron spectroscopy optical emission spectroscopy

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Tungstophosphoric heteropolyacid supported onto neutral alumina: characterization and synthesis of acetals and ketals

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Rare Metals 2007年第2期26卷 152-157页

作者： GAO Jinzhang WEI Yunxia WANG xuemei YANG wu Chemistry ＆ Chemical Engineering College Northwest Normal University Lanzhou 730070 China

Tungstophosphoric acid （HPW） catalyst supported on the neural alumina was studied. It was prepared by means of an equilibrium and incipient wetness impregnation technique. Solution of HPW in 50% V/V ethanol-water was used to impregnate Al2O3 at 25℃. It was found that the catalyst containing 30% PW by calcination at 500℃ showed a higher catalytic activity in the synthesis of acetals and/or ketals. In the following condition, that is, the molar ratio of aldehyde/ketone to glycol being 1：1.5, the mass fraction of the catalyst used was 0.5%, and the reaction time was 1.0 h; the yields of ketals and acetals could reach up to 60.5%-86.7%. Moreover, it could be easily recovered and reused.

关键词： heteropolyacid tungstophosphodc catalyst catalytic activity acetal ketal.

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A point mutation of PRL gene in pituitary prolactin- secreting adenoma induced by 17-β-estradiol in SD rats

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Chinese Science Bulletin 2000年第5期45卷 435-439页

作者： xuemei wu Rongkun Xu Department of Physiology Institute of Basic Medical Science Chinese Academy of Medical Sciences Beijing China

Animal model bearing pituitary prolactin-secreting adenomas (prolactinoma) induced by 17-β-estradiol (E2) in both eutopic pituitary and ectopic pituitary grafted under the renal capsule was generated. Northern blotting assay indicated that PRL mRNA level in eutopic prolactinomas was higher than that in normal pituitaries and ectopic prolactinomas (P<0.05 - 0.01). By polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) analysis and DNA sequencing, a point mutation from C to A occurring at -36 nt in proximal promoter of rat PRL (rPRL) gene was found only in eutopic prolactinomas. No base change was detected in ectopic prolactinomas. Fusion gene transfection assay in vitro exhibited increased activity of the mutant promoter derived from eutopic prolactinoma (P<0.01). These data suggested that the base change in the proximal promoter of rPRL gene may be associated with hyperexpression of rPRL gene in eutopic prolactinomas. The pathogenesis of eutopic and ectopic prolactinomas

关键词： PCR-SSCP prolactin-secreting adenoma rPRL gene DNA sequencing point mutation.

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Sulforaphane protects primary cultures of cortical neurons against injury induced by oxygen-glucose deprivation/reoxygenation via anti-apoptosis

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Neuroscience Bulletin 2012年第5期28卷 509-516页

作者： xuemei wu Jing Zhao Shanshan Yu Yanlin Chen , Jingxian wu Yong Zhao Department of Pathology Department of Pathophysiology Chongqing Medical University Chongqing 400016 China

Objective To determine whether sulforaphane （SFN） protects neurons against injury caused by oxygen-glucose deprivation/reoxygenation （OGD/R） and, if so, to investigate the possible mechanisms. Methods Primary cultures of neurons were prepared from the cerebral cortex of 1-day-old Sprague-Dawley rats. On days 5-6 in vitro, the neurons were exposed to OGD for 1 h, followed by reoxygenation for 24 h. Cells were treated with 0, 0.1, 0.2, 0.5, 1, 2.5, or 5 μmol/L SFN, with or without 10 μmol/L LY294002, a PI3K-specific inhibitor, during OGD/R （a total of 25 h）. After 24-h reoxygenation, MTT was used to assess viability and injury was assessed by Hoechst 33258/propidium iodide （PI） staining; immunofluorescence staining and Western blot were performed to detect molecular events associated with apoptosis. Results The MTT assay showed that 1 μmol/L SFN significantly increased viability, and Hoechst 33258/PI staining showed that the numbers of injured neurons were reduced significantly in the SFN group. Furthermore, immunofluorescence staining and Western blot showed that SFN increased Bcl-2 and decreased cleaved caspase-3 levels. Moreover, LY294002 inhibited the phosphorylated-Akt expression evoked by SFN, decreased Bcl-2 expression and increased cleaved caspase-3 expression. Conclusion SFN protects neurons against injury from OGD/R and this effect may be partly associated with an anti-apoptosis pathway.

关键词： sulforaphane oxygen-glucose deprivation apoptosis neuroprotection

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The control and optimization of macro/micro-structure of ion conductive membranes for energy conversion and storage

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Chinese Journal of Chemical Engineering 2016年第5期24卷 558-571页

作者： Xiaoming Yan Wenji Zheng Xuehua Ruan Yu Pan xuemei wu Gaohong He State Key Laboratory of Fine Chemicals School of Petroleum and Chemical EngineeringDalian University of Technology Research and Development Center of Membrane Science and Technology School of Chemical EngineeringDalian University of Technology

Ion conductive membranes(ICMs)are frequently used as separators for energy conversion and storage technologies of fuel cells,flow battery,and hydrogen pump,because of their good ion-selective conduction and low electronic ***,this feature article reviews the recent studies on the development of new nonfluorinated ICMs with low cost and their macro/micro-structure *** general,these new nonfluorinated ICMs have lower conductivity than commercial perfluorinated ones,due to their poor ion transport *** ion exchange capacity(IEC)would create more continuous hydrophilic channels,thus enhancing the ***,high IEC also expands the overall hydrophilic domains,weakens the interaction between polymer chains,enhances the mobility of polymer chains,and eventually induces larger *** micro-scale expansion and macro-scale swelling of the ICMs with high IEC could be controlled by limiting the mobility of polymer *** on this strategy,some ef ficient techniques have been developed,including covalent crosslinking,semi-interpenatrating polymer network,and ***,this review introduces the optimization of macro/microstructure of both perfluorinated and nonfluorinated ICMs to improve the ***-scale multilayer composite is an ef ficient way to enhance the mechanical strength and the dimensional stability of the ICMs,and could also decrease the content of per fluorosulfonic acid resin in the membrane,thereby reducing the cost of the perfluorinated *** side chain,multiple functionalization,small molecule inducing micro-phase separation,electrospun nano fiber,and organic–inorganic hybrid could construct more ef ficient ion transport channels,improving the ion conductivity of ICMs.

关键词： Ion conductive membranes Macrostructure Microstructure Optimization

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Seasonal variation and sources of atmospheric polycyclic aromatic hydrocarbons in a background site on the Tibetan Plateau

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Journal of Environmental Sciences 2023年第3期125卷 524-532页

作者： xuemei wu Weijun Sun Baojuan Huai LeiWang Chuntan Han Yetang Wang Wenying Mi College of Geography and Environment Shandong Normal UniversityJinan 250014China Qilian Alpine Ecology and Hydrology Research Station Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China MINJIE Institute of Environmental Science and Health Research Geesthacht 21502Germany

The study of atmospheric polycyclic aromatic hydrocarbons(PAHs) in northeastern Tibetan Plateau with fragile ecological environment and complex atmospheric circulation system is blank. To understand the characteristics and sources of persistent organic pollutants in the atmosphere of the northeastern Tibetan Plateau, we monitored levels in the central Qilian Mountain. From 2016 to 2017, we collected 45-pair(particle + gas) samples using active air samplers to investigate the sources, transport paths, and their influencing *** of PAHs were analysed with a source diagnostic model, and atmospheric transport paths were calculated. The concentration range for Σ15PAHs was 439–4666 pg/m^(3), and the average was 2015 pg/m^(3). The PAHs in central Qilian Mountain are mainly low molecular weight(LMW) PAHs. Winter concentrations of PAHs were higher than those in summer. The transport of PAHs is mainly affected by westerlies, and there are seasonal differences. Source analysis showed that PAHs mainly came from coal and biomass combustion and vehicle emissions, with seasonal differences. This study clarifies the concentration and seasonal variation of PAHs in the northern Tibetan Plateau, which is conducive to understanding the atmospheric transport process and fate of pollutants. The background site of Qilian Mountains located in the Silk Road economic belt has the value and significance of longterm observation of pollutants.

关键词： Long-range atmospheric transport Seasonal variation concentration Meteorological factors Qilian Mountain

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High magnetic field helicon plasma discharge for plasma-wall interaction studies

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Science China(Physics,Mechanics & Astronomy) 2016年第4期59卷 88-89页

作者： TianYuan Huang ChengGang Jin Jun Yu xuemei wu LanJian Zhuge College of Physics Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and TechnologySoochow University Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China Soochow University Analysis and Testing Center Soochow University

Dear Editors,Plasma-Wall Interactions(PWIs)are important for the development of magnetic confinement fusion devices such as International Thermonuclear Experimental Reactor(ITER),as they can release impurities into th... 详细信息

关键词：放电等离子体相互作用螺旋波等离子体高磁场国际热核实验反应堆核聚变装置 ITER 磁约束

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Catalytic hydrogenation performance of ZIF-8 carbide for electrochemical reduction of carbon dioxide

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Chinese Journal of Chemical Engineering 2021年第11期34卷 144-153页

作者： Shuai Fan Huiyuan Cheng Manman Feng xuemei wu Zihao Fan Dongwei Pan Gaohong He State Key Laboratory of Fine Chemicals Research and Development Center of Membrane Science and TechnologySchool of Chemical EngineeringDalian University of TechnologyDalian 116024China

The conversion of CO_(2) electrocatalytic hydrogenation into energy-rich fuel is considered to be the most effective way to carbon ***-doping carbonized ZIF-8 is proposed as carrier of the earth-rich Sn catalyst to overcome the limit of electron transfer and CO_(2) adsorption capacity of *** porous structure of Sn doped carbonized ZIF-8 is controlled by hydrothermal and carbonization conditions,which induces much higher specific surface area than that of the commercial Sn nanoparticle(1003.174 vs.7.410 m^(2)·g^(-1)).The shift of nitrogen peaks in X-ray Photoelectron Spectroscopy spectra indicates interaction between ZIF-8 and Sn,which induces the shift of electron cloud from Sn to the chemical nitrogen to enhance conductivity and regulate electron transfer from catalyst to CO_(2).Lower mass transfer resistance and Warburg resistance are investigated through EIS,which significantly improves the catalytic activity for CO_(2) reduction reaction(CO_(2)RR).Onset potential of the reaction is reduced from-0.74 V to less than-0.54 V *** total Faraday efficiency of HCOOH and CO reaches 68.9%at-1.14 V ***,which is much higher than that of the commercial Sn(45.0%)and some other Sn-based catalyst reported in the literature.

关键词： Carbon dioxide Electrochemistry Selective catalytic reduction Electrochemical hydrogen pump Nitrogen-doping carbonized ZIF-8

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Observed features of stable surface seawater isotopes across the Pacific, Indian and Southern oceans

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Acta Oceanologica Sinica 2024年第10期43卷 33-39页

作者： xuemei wu Weijun Sun Biao Tian Baojuan Huai Zhiheng Du Minghu Ding College of Geography and Environment Shandong Normal UniversityJinan 250014China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China

The marine hydrological process is still unclear due to scarce *** on stable water isotopes in surface seawater along the 33rd Chinese National Antarctic Science Expedition from November 2016 to April 2017,this study explored the hydrological processes in the Pacific,Indian and Southern *** results show that the Northwest Pacific(0°–26°N)is a region with strong evaporation(theδ18O-δD slope is 6.58),while the southern Indian Ocean is a region with strong precipitation(theδ18O-δD slope is 9.57).The influence of continental runoff and water mass mixing reduces the correlation betweenδ18O and salinity in the eastern Indian *** characteristics of the isotopes and hydrological parameters indicate that the Agulhas Front and sub-Tropical Convergence do not merge in the Antarctic–Indian Ocean *** freezing of sea ice near the Antarctic continent decreases theδ18O andδD by 0.40‰and 7.0‰,respectively,compared with those near 67°*** study is helpful for understanding marine hydrological processes and promoting the understanding and research of the nature of ocean responses in the context of climate change.

关键词： spatial variability surface seawater isotopes δ18O-salinity relation water mass fronts

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