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Effects of precipitation and landuse on runoff during the past 50 years in a typical watershed in the Loess Plateau, China

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International Journal of Sediment Research 2009年第3期24卷 352-364页

作者： Huaxing BI1, Bin LIU2, Jie WU3, Lei YUN3, Zhihan CHEN2 and Zhewei CUI31 Prof. in hydrology, College of soil and water conservation, Box 67, beijing Forestry University, 35 Qinghua East Road, haidian district, beijing 100083, China, 2 Researcher in hydrology, Xifeng station of soil and water conservation, Xifeng, Gansu Province, China 3 Graduate Assis., College of soil and water conservation, beijing Forestry University, beijing 100083, China Prof. in hydrology College of soil and water conservation Box 67 Beijing Forestry University 35 Qinghua East Road Haidian District Beijing 100083 China Researcher in hydrology Xifeng station of soil and water conservation Xifeng Gansu Province China Graduate Assis. College of soil and water conservation Beijing Forestry University Beijing 100083 China

In the past century, great progress has been made worldwide in our understanding of forest-water relationship. The successful forestation programs implemented in China-which have improved the ecological environmental conditions-have gained the attention of many researchers and highlighted the relationship between forestation and water yields. The arid and semi-arid Loess Plateau has received attention from water engineers and eco-hydrological researchers in China because of a shortage in water resources. We selected one of the oldest stations conducting soil and water conservation experiments, the Xifeng soil and water conservation station, and chose the Nanxiaohe catchment and its paired catchments (Yangjiagou catchment and Dongzhuanggou catchment) as our research areas. Trends in precipitation, air temperature, streamflow over the past 50 years, and the effect of changing land use on streamflow were analyzed. The Mann-Kendall test showed that precipitation had a negative trend (downward trend), whereas air temperature showed a positive trend (upward trend) from the past to present in the Nanxiaohe catchment. However, the trends seen in precipitation, air temperature did not contain any "jumping points." The paired catchment approach is used to detect the effects of land cover change on hydrology in the Yangjiagou and the contrast catchment, i.e., Dongzhuanggou catchment in our study. The results showed a large change in land use in the Yangjiagou catchment from 1954 to 2008. An increase in forested land (from 0% to 40.08% from 1954 to 2008) and a reduction of bare land (from 51.26% to 5.50% from 1954 to 2008) accounted for a large part of the change in land use. However, the land use changed little in the contrast catchment. The comparison of streamflow in the paired catchments showed that forestation reduced streamflow by 49.63% (or 6.5 mm) each year.

关键词： Surface water hydrology Climate variability/change Forests Land use/land cover change Loess Plateau of China

Analysis of an Auto Black Box in Accident Reviewing

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Analysis of an Auto Black Box in Accident Reviewing

The 2~nd International Forum of Automotive Traffic Satety(INFATS2002)

作者： XU Xiang-yang,LIU Bin (1.Dept of Automotive Engineering,Beihang University,beijing 100083 2.37 XueYuan Road,haidian district beijing,China,100083)

＜正＞According to the theory of black box used in plane,a new accurate and efficient method for car accident reviewing is presented to overcome the shortcomings of car accident reviewing method being used.

关键词： accident reviewing black box

Feasibility Analysis of Waste Phosphate Rock Treatment for Pollution Control of Coal Waste Piles with Spontaneous Combustion by Inhibiting Pyrite Oxidation

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Feasibility Analysis of Waste Phosphate Rock Treatment for P...

海峡两岸三地环境与资源学术研讨会暨第二届中国环境资源与生态保育学会会员代表大会

作者： ZHANG Lei,XU Yunqiang Institute of Land Reclamation and Ecological Restoration,China University of Mining and Technology (beijing),D11 Xueyuan Road,haidian district,beijing,China 100083,

With spontaneous combustion,coal waste piles release sulfur dioxide,hydrogen sulfide,carbon monoxide and nitrogen oxides,which become the most serious source of pollution and threaten the ecological safety and human health in mining *** oxidation is the key of pollution release in coal waste piles and numerous studies have identified the potential of phosphate rock to control pyrite oxidation. So it seems to be a new approach to use waste phosphate rock in tailings to control the pollution of coal waste piles with spontaneous *** paper analyses the feasibility of using the waste phosphate rock treatment to prevent coal waste piles spontaneous combustion to control pollution and the role of waste phosphate rock playing,including formatting of oxidation film and bio-film,which act as a physical and chemical barrier,and providing nutrition for microbial and plant.

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Technique and Policy Issues on Irrigation Agriculture Development and Countermeasures in China

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Technique and Policy Issues on Irrigation Agriculture Develo...

国际农业工程大会

作者： Fahu Li, Dr.College of Hydraulic and Civil Engineering, China Agricultural University, POB 295, No. 17, Qinghua Donglu, haidian district, beijing 100083, China

＜正＞ Agriculture development is comprehensively affected by natural resource, society and economic development level. Agriculture is an industry with low economic profit but it is special important for society stability and country *** agriculture plays an important role on grain supply, but water resource shortage constrains its development. China is a developing country with vast population;Issues that

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Influence of carbon black activation on the AC electrical properties of conductive carbon black/polypropylene composites

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Influence of carbon black activation on the AC electrical pr...

The Fifth China-Japan Seminar on Advanced Engineering Plastics, Polymer Alloys and Composites

作者： DING Nai-Xiu,ZHAN Mao-Sheng School of Materials Science and Engineering,beijing University of Aeronautics and Astronautics 37XueYuan Road,haidian district,beijing 100083.,PR China

Carbon black was first activated by grafting and coupling *** the grafted carbon black,coupled carbon black,together with the unmodified carbon black were filled into polypropylene to prepare three kinds of composites *** measurements of Fourier Transform Infrared Spectroscopy (FT1R) and alternating current (AC) electrical properties were performed on the *** from the result of FTIR spectra it can be found that different groups are bonded to the surface of carbon black after *** the corresponding conductive composites,it was found that the value of percolation threshold decreases and the electrical conductivity improves consequently after the carbon black *** influence of carbon black activation on the AC electrical properties of the composites and their variation with frequency was *** AC conduction mechanism was discussed and the conduction model was constructed based on the ***: AC electrical properties;Polypropylene;Carbon black;Activation;Grafting;Coupling

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基于遗传算法的非线性参数估计器

系统仿真学报 1995年第4期7卷 43-47页

作者：唐淑琴武颖琪北京市海淀区学院路37号中国系统仿真学会

提出非线性参数估计的遗传算法方法。遗传算法是一种基于自然选择和自然遗传学机理的全局搜索学习算法。文中介绍了遗传算法的基本原理和参数估计算法。仿真实例验证了该方法的良好特性。

关键词：遗传算法参数估计非线性参数估计器

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天然气管道可靠性特征量

天然气工业 1997年第6期17卷 50-53页

作者：宋东昱严大凡中国石油天然气总公司石油规划设计总院石油大学

依据四川石油管理局输气公司经营的１２条输气管道近２５年的运行数据和陕甘宁盆地中部气田先导开发试验区地面集输管网近两年的运行数据，运用数理统计理论，对天然气管道的可靠性特征量进行了统计，并介绍了天然气管道事故分布统计及... 详细信息

依据四川石油管理局输气公司经营的１２条输气管道近２５年的运行数据和陕甘宁盆地中部气田先导开发试验区地面集输管网近两年的运行数据，运用数理统计理论，对天然气管道的可靠性特征量进行了统计，并介绍了天然气管道事故分布统计及其参数估值的步骤，给出了天然气干线管道事故分布、维修时间分布类型及其估值以及采气管线、集气支线、站内管线的事故率。

关键词：天然气管道油气集输可靠性

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Apple maturity discrimination and positioning system in an apple harvesting robot

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Apple maturity discrimination and positioning system in an a...

The First International Conference on Computers and Computing Technologies in Agriculture

作者： LIU ZHAOXIANG LIU GANG~* Key Laboratory of Modern Precision Agriculture System Integration Research China Agricultural University PO Box 125 Qinghua Donglu 17 haidian district beijing 100083 China

＜正＞To obtain the spatial position and the maturity of apples,a system based on a multi-spectral vision technique and a trigonometrical survey technique was *** comprised a 2D vision sensor and a *** 2D vision sensor was constructed using two laser beams:a red laser beam（685 nm） and an infrared laser beam （830 nm）.Beams were installed perpendicularly to one another,and they were united along the same optical axis using a cold *** united beam was transmitted into an apple through a full reflecting mirror and a swinging mirror;the reflected beam from the apple was focused onto the sensitive surface of a position sensitive device（PSD） through a focusing *** two output signals of the PSD were transmitted into a microprocessor after a set of processes includingⅠ/Ⅴconversion,amplification, filtering and *** microprocessor transmitted the output information of position and maturity to a manipulator through the RS 232 bus. To evaluate the performance of the system,some tests were performed.

关键词： multispectral vision PSD robot trigonometrical survey

The passivation role of the Si based film on the crystallinesillicon substrate

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The passivation role of the Si based film on the crystalline...

第二届晶体硅太阳电池及材料科学与技术国际研讨会

作者： Zhangyan12 Zhao lei1 Diao hongweit Zeng xiangboa Zhou chunlan1 Wang wenjing1 Guo bei2 Zhang bing2 Li hongyuan2 Institute of electrician Chinese Academy of Sciences haidian district beijing 100083 China School of Material Science and Engineering Hebei University of Technology Tianjin 300130 China. Institute of Semiconductors Chinese Academy of Sciences haidian district beijing 100083 China.

＜正＞Combination of characteristics of both crystalline and thin film Si,the amorphous /crystalline silicon heterojunction solar cells have attracted a growing amount of attention because of its low-temperature processes,high efficiency,and low cost *** solar cells were considered as interfacial *** the photo-carrier generation occurs mostly in the c-Si, it is known that the interface recombination between c-Si/a-Si:H,the surface passivation of the crystalline silicon substrate is a critical *** amorphous silicon film on texturised c-Si heterojunction solar cells with 20.1% efficiency developed by Sanyo were achieved by insert a thin hydrogenated amorphous silicon（a-Si:H） buffer *** goal of the paper is to research the the passivation role of the si based film on the crystalline silicon *** Deposite a series of thin film silicon layers on polished crystalline silicon substrate by *** influence of RF power,substrate temperature,hydrogen dilution and gas pressure have been systematically investigated on the properties of Si based *** the construction of the Si based films by laman spectrum and test the minority carrier lifetime by *** is found that the minority carrier lifetime of the silicon substrate became much better than *** shows that the Si based films play an important role on the passivation of the silicon substrate。And the passivation is related to the microstructure of the si based film,the best passivation role can be achieved by Complete amorphous si based *** also showed in this paper about the direction to make better si based films by PECVD.

关键词： PECVD passivation thin film