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Characteristics of urban ozone level in Hong kong

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Journal of Environmental Sciences 2001年第1期13卷 1-7页

作者： D.Y.C.LEUnG D.n.zhang Department of Mechanical Engineering The University of Hong KongPokfulam RoadHong KongChina Research Institute of Environmental Engineering East China University of Science and TechnologyShanghai 200237China

The long term trend of ozone level in Hong Kong has been investigated. One of the characteristics of ozone level in Hong Kong is the existence of autumn maximum and summer minimum. Observations of the diurnal variation of ozone level have been made in different area categories. There are early morning peak and afternoon peak occurred in the diurnal variation, which are different from some metropolitans where only an afternoon peak is observed. A negative correlation coefficient was found between monthly ozone level with nitric oxide level. On the contrary, there is a positive correlation between ozone and nitrogen dioxide. The positive correlation coefficient between nitric oxide and nitrogen dioxide shows that the total amount of nitric oxide emitted from a series of moving and fixed sources greatly exceeded the stoichiometric amount of ozone formed from chemical reactions of precursors and long distance transportation.

关键词： ozone urban air pollution Hong kong China

Aerodynamic load control on a dynamically pitching wind turbine airfoil using leading-edge protuberance method

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Acta Mechanica Sinica 2020年第2期36卷 275-289页

作者： Y.n.zhang M.M.zhang C.Cai J.Z.Xu Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China The Key Laboratory of Wind Energy Utilization of CAS Beijing 100190China University of Chinese Academy of Sciences Beijing 100049China Dalian national Laboratory for Clean Energy Chinese Academy of SciencesDalian 116023China

The aerodynamic loads of wind turbine blades are substantially affected by dynamic stall induced by the variations of the angle of attack of local airfoil *** purpose of the present study is to explore the effect of leading-edge protuberances on the fluctuation of the aerodynamic performances for wind turbine airfoil during dynamic *** experimental investigation is carried out by a direct force measurement technique employing force balance at a Reynolds number Re=2×*** phase-averaged and instantaneous aerodynamic loads of the pitching airfoil,including the baseline and the wavy airfoil,are presented and *** phase-averaged results indicate that the effects of dynamic stall for the wavy airfoil can be delayed or minimized compared to the baseline airfoil,and the negative damping area of the wavy airfoil is significant decreased in full-stall *** effects of leading-edge protuberances are more notable at a higher reduced *** the instantaneous aerodynamic loads of the wavy airfoil,there is an observable reduction in fluctuations compared with baseline ***,spectral analysis is applied to quantitatively undercover the nonstationary features of the instantaneous aerodynamic *** is found that the leading edge protuberances can reduce the harmonics of the aerodynamic force signal,and enhance the stability of the aerodynamic loads under different reduced *** conclusion,leading-edge protuberances are found effective to reduce the fluctuation characteristics of the aerodynamic loads during the dynamic stall process,and help to improve the stability and prolong the service life of the wind turbine blades.

关键词： Wind turbine airfoil Dynamic stall Loads control Leading-edge protuberance Aerodynamic experiment

2018-2022年浙江省钩端螺旋体病流行特征与时空聚集性分析

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中国人兽共患病学报 2024年第9期40卷 855-859页

作者：郭颂姚文武刘营施旭光任江萍张蓉杨章女孙继民浙江省疾病预防控制中心

目的分析2018-2022年浙江省人间钩端螺旋体病(钩体病)的流行特征与时空分布特点，为制定钩体病防控策略提供科学依据。方法钩体病数据来源于中国疾病预防控制信息系统，采用描述性流行病学方法进行分析。应用ArcMap 10.8软件进行空间... 详细信息

目的分析2018-2022年浙江省人间钩端螺旋体病(钩体病)的流行特征与时空分布特点，为制定钩体病防控策略提供科学依据。方法钩体病数据来源于中国疾病预防控制信息系统，采用描述性流行病学方法进行分析。应用ArcMap 10.8软件进行空间自相关分析和结果可视化展示，通过SaTScan 10.1.2软件进行时空扫描，分析和描述钩体病时空聚集性特征。结果浙江省2018-2022年共报告人间钩体病病例255例，包含1例死亡病例，年均发病率为0.084 3/10万，年均死亡率为0.000 3/10万。8月至10月为浙江钩体病高发月份，病例以45～86岁的中年及老年人为主(221例，86.67%),65～69岁年龄组发病人数最多(57例),男女比例为4.67∶1,职业主要为农民(190例，74.51%)。温州市和丽水市的5年累计发病数(201例)占总发病数的78.82%。2018-2022年全局空间自相关分析表明全省钩体病发病率呈现空间正自相关；局部空间自相关分析显示，“高-高”聚集区主要集中在浙江省南部山地丘陵地带的温州市、丽水市和台州市。时空扫描分析在浙江省南部发现3个高发聚集区域。结论浙江省钩体病发病呈现明显的地区聚集性和季节性，高发区域主要位于浙江南部的山地和丘陵地区，病例以中老年男性农民为主，需加强农村居民健康教育，防范潜在流行风险。

关键词：钩端螺旋体病流行特征空间自相关时空聚集性

ERP Solution for Large & Medium State Firms

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Wuhan University Journal of natural Sciences 2001年第Z1期6卷 612-618页

作者： Philip n.zhang CEO of Wuhan Philwong Computer Technology Co.Ltd.

The application and development process of MRP-II /ERP can be divided into four stages as following. This period covers almost the entire 1980s', when the MRP-II was first introduced, implemented and partially applied to Chinese manufacturing SOEs (mostly machine tool manufacturing, automobile manufacturing). Because many obstacles are encountered and effect was limited, the period was also referred to "Three One-Third Theory" phase, that is one-third of foreign MRP-II software can be used, one-third needs to be modified before use and the rest one third is useless.

关键词： ERP Solution for Large Medium State Firms BPR

Synthesis and Crystal Structure of a Genistein-derived Compound

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Chinese Journal of Structural Chemistry 2008年第2期27卷 200-204页

作者： zhang Li-n SHI Lei FAnG Rui-Qin ZHU Hai-Liang School of Life Sciences Nanjing University Nanjing 210093 China

A genistein derivative, 5-hydroxy-3-（4-hydroxyphenyl）-7-（2-（piperidin- 1-yl）ethoxy）- 4H-chromen-4-one 3, was designed, prepared and structurally characterized by single-crystal X-ray diffraction. X-ray structure analysis reveals that 3 crystallizes in the orthorhombic system, space group Pbca, with a = 16.238（3）, b = 10.308（2）, c = 22.987（5）A, V = 3847.6（13）A3, Z = 8,μ= 0.093 mm^-1, Dc = 1.317 g/cm^3, F（000） = 1616, R = 0.0789 and wR = 0.1554 for 1463 observed reflections with I 〉 2σ（I）.

关键词： genistein crystal structure derivative 1,2-dibromoethane piperidine

Corrosion and cavitation erosion resistance enhancement of cast ni–Al bronze by laser surface melting

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Journal of Iron and Steel Research International 2022年第2期29卷 359-369页

作者： Q.n.Song Y.Tong H.L.Li H.n.zhang n.Xu G.Y.zhang Y.F.Bao W.Liu Z.G.Liu Y.X.Qiao Engineering Research Center of Dredging Technology of Ministry of Education Hohai UniversityChangzhou213022JiangsuChina College of Mechanical and Electrical Engineering Hohai UniversityChangzhou213022JiangsuChina College of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang212003JiangsuChina

Laser surface melting (LSM) was applied on a cast ni–Al bronze (nAB), which was a crucial material for marine ship propellers. A 720 μm-thick LSM layer with fine equiaxed and dendritic microstructures was obtained. After immersion for 30 days, the corrosion rate of cast nAB was reduced by 25% after LSM. Preferential corrosion occurred and deep corrosion pits appeared at α + κIII microstructure for the cast nAB. LSM nAB underwent general corrosion, and a much more protective film formed on the surface because of the homogenized microstructure. The mass loss of the cast nAB was approximately 2.1 times larger than that of LSM nAB after cavitation erosion (CE) in 3.5 wt.% naCl solution for 5 h. For the two materials, the mechanical impact effect was dominantly responsible for CE damage. Therefore, the improved hardness and homogenized microstructure contributed to the improved CE resistance of LSM nAB. CE destructed the film, shifted the open circuit potential toward a more negative value, and raised the current density by an order of magnitude. Corrosion at the cast eutectoid microstructure and the dendrites of LSM nAB facilitates the degradation under the cavitation attack. CE-corrosion synergy was largely caused by corrosion-enhanced-CE.

关键词： Laser surface melting ni-Al bronze Microstructure Corrosion Cavitation erosion Synergy

Comparing hydrogen embrittlement behaviors of two press hardening steels:2 GPa vs.1.5 GPa grade

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Journal of Materials Science & Technology 2022年第29期124卷 109-115页

作者： Z.H.Cao B.n.zhang M.X.Huang Department of Mechanical Engineering The University of Hong KongPokfulam RoadHong KongChina

*** The pursuit of advanced high-strength steels(AHSS)has been rising for the automobile industry to build lightweight and fuelefficient vehicles without compromising crashworthiness[1,2].The group of press hardening steels(PHS)is an excellent candidate that comprises high strength,high toughness,and good formability,which are optimal to build intrusion resistant components such as(ⅰ)A/B-pillar reinforcements,(ⅱ)bumper and door beams.

关键词： strength toughness steels

PRECIPITATIOn AnD GROWTH OF PEROVSKITE PHASE In TITAnIUM BEARInG BLAST FURnACE SLAG

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Acta Metallurgica Sinica(English Letters) 2007年第1期20卷 9-14页

作者： Z.Z. Guo T.P. Lou L. zhang L.n. zhang Z.T. Sui School of Materials and Metallurgy Northeastern University Shenyang 110006 Ghina

The effects of transformation of slag composition and additive agents on the morphology, the precipitation behavior, the crystal growth, and the volume fraction (VF) of perovskite (CaO·¤TiO_2) crystal in the Ti-bearing blast furnace slags were investigated. As the morphology of perovskite is dispersed in molten slags, the crystal growth mechanism of the melting of fine dendrites and the coarsening of large grains exist throughout the solidification of molten slags. With the increase of CaO and Fe_2O_3 content, VF of perovskite obviously increases. However, high basicity leads to the viscosity of slag, which results in the reduction of the average equivalent diameter (AED). The experimental results showed that the presence of the additives CaF_2 and MnO efficiently decreased the viscosity of the slags, and obviously improved the morphology of perovskite and promoted its growth.

关键词： perovskite phase Ti-bearing blast furnace slag precipitation additive agent

Effect of solute atom concentration and precipitates on serrated flow in Mg-3nd-Zn alloy

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Journal of Materials Science & Technology 2018年第7期34卷 1236-1242页

作者： W.H.Wang D.Wu R.S.Chen X.n.zhang State Key Laboratory of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University The Group of Magnesium Alloys and Their Applications Institute of Metal Research Chinese Academy of Sciences

Influence of solute atom concentration and precipitates on serrated flow, i.e., Portevin-Le Chatelier effect, was studied in Mg-3nd-Zn alloy by tensile test at 250℃ with a strain rate of l x 10^-3 s^-1 Microstructure and tensile property of the Mg-3nd-Zn alloy in solution and aging conditions were also investigated. Results indicate that the serrated flow was weakened with aging time, and geometry of the serrations changed from sharp to rounded corner. Through analyzing the mechanism of the interactions between dislocations and solute atoms, it was identified that the precipitates did not only weaken the serrated flow due to the decrease in the concentration of solute atom, but also regulate the serration type by restraining the movement of dislocations during high temperature deformation.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

关键词： Magnesium alloy Serrated flow Precipitate Heat treatment Deformation behavior