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Mercury in leaf litter in typical suburban and urban broadleaf forests in China

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Journal of Environmental Sciences 2011年第12期23卷 2042-2048页

作者： Zhenchuan niu Xiaoshan zhang zhangwei Wang Zhijia Ci Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

To study the role of leaf litter in the mercury （Hg） cycle in suburban broadleaf forests and the distribution of Hg in urban forests, we collected leaf litter and soil from suburban evergreen and deciduous broadleaf forests and from urban forests in Beijing. The Hg concentrations in leaf litter from the suburban forests varied from 8.3 to 205.0 ng/g, with an average （avg） of （49.7 ± 36.9） ng/g. The average Hg concentration in evergreen broadleaf forest leaf litter （50.8 ± 39.4） ng/g was higher than that in deciduous broadleaf forest leaf litter （25.8 ± 10.1） ng/g. The estimated Hg fluxes of leaf litter in suburban evergreen and deciduous broadleaf forests were 179.0 and 83.7 mg/（ha·yr）, respectively. The Hg concentration in organic horizons （O horizons）（（263.1 ± 237.2） ng/g） was higher than that in eluvial horizons （A horizons）（（83.9 ± 52.0） ng/g）. These results indicated that leaf litterfall plays an important role in transporting atmospheric mercury to soil in suburban forests. For urban forests in Beijing, the Hg concentrations in leaf litter ranged from 8.8–119.0 （avg 28.1 ± 16.6） ng/g, with higher concentrations at urban sites than at suburban sites for each tree. The Hg concentrations in surface soil in Beijing were 32.0–25300.0 ng/g and increased from suburban sites to urban sites, with the highest value from Jingshan （JS） Park at the centre of Beijing. Therefore, the distribution of Hg in Beijing urban forests appeared to be strongly influenced by anthropogenic activities.

关键词： mercury broadleaf forests leaf litter soil flux

Effect of Welding Paramenter on Joint Property of Aluminum Matrix Composite in Liquid-Phase-Impacting Diffusion Welding

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Journal of Materials Science & Technology 2003年第z1期19卷 195-198页

作者： Wei GUO Qingchang MENG Jitai niu Xinmei zhang The National Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology1 Harbin 150001 China The National Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology1 Harbin 150001 China The National Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology1 Harbin 150001 China The National Key Laboratory of Metal Matrix Composite Shanghai Jiao Tong University Shanghai 200030 China The National Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology1 Harbin 150001 China

In this paper, a new method for welding SiCp/101A was put forward. It is LPI (liquid-phase-impacting) diffusionwelding. Through LPI diffusion welding SiCp/101A aluminum, the effect of welding parameters on the weldedjoint property was investigated, and the optimal welding parameters were brought forward at the same time. Themicrostructure of joint was analyzed by means of optical-microscope, scanning electron microscope in order to studythe relationship between the macro-properties of joint and the microstructure. The results show that LPI diffusionwelding could be used for welding aluminum matrix composites SiCp/101A successfully.

关键词： Aluminum matrix composite, Liquid-phase-impacting diffusion welding, SiCp/101A

Experimental research on hydrophilic characteristics of natural soft rock at high stress state

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International Journal of Mining Science and Technology 2015年第3期25卷 489-495页

作者： Guo Hongyun Lei Xiangyang zhang Yumei Yang Guoxing niu zhang The Engineering Design Research Institute of Equipment of PLA Astronaut Center of China China Taiyuan Satellite Launch Center

In order to study features of rock–water interaction, a self-developed experimental system called Intelligent Testing System for Water Absorption in Deep Soft Rocks(ITSWADSR) was utilized to analyze the hydrophilic behaviors of natural soft rock at high stress state. Combining X-ray diffraction and mercury injection test, main influencing factors on hydrophilic characteristics were studied. According to the results, it could be concluded as the following:(1) the effective porosity, and the content of illite, illite/smectite formation(S = 5%) and kaolinite have positive correlation with the water absorption capacity of rock; meanwhile, the initial moisture content, fractal dimension of effective pores, illite/smectite formation(S = 30%) and chlorite present negative correlation;(2) among the positive factors, the ascending order is kaolinite, illite/smectite formation(S = 5%) and illite;(3) the descending order among the negative factors are chlorite, illite/smectite formation(S = 30%) and fractal dimension of the effective pores;(4) influence of effective porosity on the pressurized water absorbing capacity of rock is minimal, while it is maximal in the process of no pressurized water absorption.

关键词： Natural soft rock Water absorption tests X-ray diffraction Mercury injection test Hydrophilic characteristics

Light Trapping Effect in Wing Scales of Butterfly Papilio peranthus and Its Simulations

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Journal of Bionic Engineering 2013年第2期10卷 162-169页

作者： Zhiwu Han Shichao niu Lufeng zhang Zhenning Liu Luquan Ren Key Laboratory of Bionic Engineering (Ministry of Education China) Jilin University Changchun 130022 P. R. China

Broadband light trapping effect and arrays of sub-wavelength textured structures based on the butterfly wing scales are applicable to solar cells and stealth technologies. In this paper, the fine optical structures in wing scales of butterfly Papilio peranthus, exhibiting efficient light trapping effect, were carefully examined. First, the reflectivity was measured by reflectance spectrum. Field Emission Scanning Electronic Microscope （FESEM） and Transmission Electron Microscope （TEM） were used to observe the coupling morphologies and structures of the scales. Then, the optimized 3D model of the coupling structure was created combining Scanning Electron Microscope （SEM） and TEM data. Afterwards, the mechanism of the light trapping effect of these structures was analyzed by simulation and theoretical calculations. A multilayer nano-structure of chitin and air was found. These structures are effective in increasing optical path, resulting in that most of the incident light can be trapped and adsorbed within the structure at last. Furthermore, the simulated optical results are consistent with the experimental and calculated ones. This result reliably confirms that these structures induce an efficient light trapping effect. This work can be used as a reference for in-depth study on the fabrication of highly efficient bionic optical devices, such as solar cells, photo detectors, high-contrast, antiglare, and so forth.

关键词： butterfly wing scale light trapping structures biomimetic functional surfaces

Discovery of super-silicic and super-titanic garnets in garnet-pyroxenite in Zhaheba and its geological significance

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Chinese Science Bulletin 2008年第14期53卷 2186-2191页

作者： niu HeCai zhang HaiXiang SHAN Qiang YU XueYuan Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China

Super-silicic garnet which exists stably at more than 5 GPa is a typical ultra-high pressure mineral. The super-silicic garnet and super-titanic garnet were discovered for the first time in garnet-pyroxenite of early Paleozoic Zhaheba-Aermantai orogenic belt in north Xinjiang. Our study indicates that these su- per-silicic garnets as well as super-titanic garnets were formed at a depth of at least 300 km. Their host rock―― garnet-pyroxenite is one kind of ultra-pressure metamorphic rocks which is related to the ul- tra-deep subduction of the oceanic crust. Thus, the early Paleozoic Zhaheba-Aermantai orogenic belt is related to the ultra-deep subduction of the Paleo-Asian oceanic crust.

关键词：蛇纹石辉岩石榴石变质作用

Iron stability in drinking water distribution systems in a city of China

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Journal of Environmental Sciences 2006年第1期18卷 40-46页

作者： niu zhang-bin WANG Yang zhang Xiao-jian HE Wen-fie HAN Hong-da YIN Pei-jun Department of Environment Science and Technology Tsinghua University Beijing 100084 China Tianjin Water Works Limited Company Tianjin 300000 China

A field study on the estimation and analysis of iron stability in drinking water distribution system was carried out in a city of China. The stability of iron ion was estimated by pC-pH figure. It was found that iron ion was unstable, with a high Fe （OH）3 precipitation tendency and obvious increase in turbidity. The outer layer of the corrosion scale was compact, while the inner core was porous. The main composition of the scale was iron, and the possible compound constitutes of the outer scale were α-FeOH, γ-FeOOH, α-Fe2O3, γ-F2O3, FeCl3, while the inner were Fe3O4, FeCl2, FeCO3. According to the characteristics of the corrosion scale, it was thought that the main reason for iron instability was iron release from corrosion scale. Many factors such as pipe materials, dissolved oxygen and chlorine residual affect iron release. Generally, higher iron release occurred with lower dissolved oxygen or chlorine residual concentration, while lower iron release occurred with higher dissolved oxygen or chlorine residual concentration. The reason was considered that the passivated out layer of scale of ferric oxide was broken down by reductive reaction in a condition of low oxidants concentration, which would result more rapid corrosion of the nine and red water phenomenon.

关键词： chlorine residual corrosion scale dissolved oxygen drinking water distribution systems iron release iron stability

Relationship Between Myocardial Injury and Expression of PGC-1α and Its Coactivators in Chronic Keshan Disease

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Current Medical Science 2022年第1期42卷 85-92页

作者： Shuai JIANG Qian-ru YE Rong-xia ZHEN Juan-niu zhang Yi-yi zhang Xu LIU Jie HOU Institute of Keshan Disease Chinese Center for Endemic Disease ControlHarbin Medical UniversityHarbin 150081China Affiliated Hospital of Jilin Medical College Jilin 132013China Hangzhou Center for Disease Control and Prevention Hangzhou 310021China Sanya Institute of Technology Sanya 572022 China Inner Mongolia Autonomous Region Mental Health Center Hohhot010010China

Objective:Keshan disease(KD)is a mitochondrial *** present study explored the roles of peroxisome proliferator-activated receptor(PPAR)-y coactivator-la(PGC-la),the key regulator of mitochondrial structure and function,and its coactivators in myocardial injury in chronic ***,the usefulness of these molecules in the diagnosis of chronic KD was assessed.

关键词： Keshan disease peroxisome proliferator-activated receptor-y coactivator-la myocardial injury lactate dehydrogenase

Mechanism of laser beam welding for SiC_P/6063Al composite

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Rare Metals 2002年第2期21卷 123-126页

作者： niu Jitai, zhang Deku, and JI GuojuanNational Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, China Harbin Institute of Technology National Key Laboratory of Advanced Welding Production Technology Harbin 150001

The laser beam welding technique was used to process SiCparticles/6063Al alloy matrix composite, the in- fluence of laserpower and welding speed on the properties of joint was *** the laser beam power with same welding speed can make thequantity and size of Al_4C_3 decreased, and the ineractive mechanismof the reinforcing particles and the matrix in the joint and thecauses for joint strength reduction were analyzed. Increasing weldingspeed properly can improve the distribution of energy and restrainthe interfacial reaction in the molten pool, an measures for impovingwere proposed.

关键词： laser beam welding SiC_p joint interfacial

A Mild and Efficient Deprotection of Geminal Diacetates Catalyzed by FeCl3 ·6H2O in Ionic Liquid

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有机化学 2003年第Z1期23卷 107-108页

作者： GUO Hai-Ming niu Hong-Ying zhang Xin-Ying WANG Jian-Ji School of Chemical and Environmental Sciences Key Laboratory of Environmental Science and Engineering for Colleges and Universities of Henan Province Henan Normal University Xinxiang 453002 School of Chemical and Environmental Sciences Key Laboratory of Environmental Science and Engineering for Colleges and Universities of Henan Province Henan Normal University Xinxiang 453002 School of Chemical and Environmental Sciences Key Laboratory of Environmental Science and Engineering for Colleges and Universities of Henan Province Henan Normal University Xinxiang 453002 School of Chemical and Environmental Sciences Key Laboratory of Environmental Science and Engineering for Colleges and Universities of Henan Province Henan Normal University Xinxiang 453002

　　The selective deprotection of geminal diacetates promoted by FeCl3·6H2O in the ionic liquid [bmim] [BF4] canbe efficiently achieved in good yields. The ionic liquid and the catalyst can be recycled easily and the... 详细信息

关键词： ionic liquid