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Hyperconcentrated flows as influenced by coupled wind-water processes

Science china Earth sciences 2005年第11期48卷 1990-2000页

作者： XU Jiongxin institute of Geographical sciences and Natural Resources Research, chinese academy of sciences Key laboratory of Water Cycle and Related Land Surface Processes, chinese academy of sciences, beijing 100101, china Key laboratory of Water Cycle and Related Land Surface Processes Chinese Academy of Sciences Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China

Using data from more than 40 rivers in the middle Yellow River basin, a study has been made of the influence of coupled wind-water processes on hyperconcentrated flows. A simple “vehicle” model has been proposed to describe hyperconcentrated flows. The liquid phase of two-phase flows is a “vehicle”, in which coarse sediment particles are carried as solid-phase. The formation and characteristics of hyperconcentrated flows are closely related with the forma-tion and characteristics of this liquid-phase and solid-phase. Surface materials and geomorphic agents of the middle Yellow River basin form some patterns of combination, which have deep influence on the formation and characteristics of liquid- and solid-phases of hyperconcentrated flows. The combination of high percentages of relatively coarse material with low percentages of fine material appears in the area predominated by the wind process, where the supply of rela-tively coarse sediment is sufficient, but the supply of relatively coarse sediment is not. The com-bination of low percentages of relatively coarse material with high percentages of fine material appears in the area predominated by the water process, where the supply of fine sediment is sufficient, but the supply of fine sediment is not. In the area predominated by coupled wind-water processes appears the combination of medium percentages of coarse and fine materials, and thus both coarse and fine sediments are in relatively sufficient supply. The manner in which the mean annual sediment concentrations of liquid- and solid-phases vary with total suspended sediment concentration is different. With the increased total suspended sediment concentration, mean annual sediment concentration of liquid-phase increased to a limit and then remained constant; however, mean annual sediment concentrations of solid-phase in-creased continuously. Thus, the magnitude of total suspended sediment concentration depends on the supply conditions of relatively coarse sedime

关键词： river sediment, hyperconcentrated flows, liquid-solid two-phase flows, wind process, fluvial process, Yellow River

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A new trust region algorithm for image restoration

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Science china Mathematics 2005年第2期48卷 169-184页

作者： WEN Zaiwen & WANG Yanfei State Key laboratory of Scientific Engineering Computing, institute of Computational Mathematics and Scientific/Engineering Computing, academy of Mathematics and System sciences, chinese academy of sciences, beijing 100080, china National Key laboratory on Remote Sensing Science, institute of Remote Sensing Applications, chinese academy of sciences, beijing 100101, china State Key laboratory of Scientific Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing China National Key laboratory on Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing China

The image restoration problems play an important role in remote sensing and astronomical image analysis. One common method for the recovery of a true image from corrupted or blurred image is the least squares error (LSE) method. But the LSE method is unstable in practical applications. A popular way to overcome instability is the Tikhonov regularization. However, difficulties will encounter when adjusting the so-called regularization parameter a. Moreover, how to truncate the iteration at appropriate steps is also challenging. In this paper we use the trust region method to deal with the image restoration problem, meanwhile, the trust region subproblem is solved by the truncated Lanczos method and the preconditioned truncated Lanczos method. We also develop a fast algorithm for evaluating the Kronecker matrix-vector product when the matrix is banded. The trust region method is very stable and robust, and it has the nice property of updating the trust region automatically. This releases us from tedious finding the regularization parameters and truncation levels. Some numerical tests on remotely sensed images are given to show that the trust region method is promising.

关键词： trust region algorithm, image restoration, Lanczos method, Kronecker matrix-vector product, preconditioning.

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Inorganic chemical composition and source signature of PM2.5 in beijing during ACE-Asia period

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Science Bulletin 2003年第10期48卷 1002-1005页

作者： ZHANG Renjian, XU Yongfu & HAN Zhiwei LAPC, institute of Atmospheric Physics, chinese academy of sciences, beijing 100029, china LAPC Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

Aerosol samples for PM2.5 were collected in beijing for 38 consecutive days from March to April 2001 using an IMPROVE Sampler. Concentrations of 20 elements in PM2.5 were determined using a PIXE method. Results show that the average mineral dust concentration of PM2.5 was 14.6 mg/m3 during the observation period. On the sand-dust event days of March 21 and April 10, dust PM2.5 mass concentrations were 62.4 and 54.1 mg/m3, respectively. These demonstrate that fine particle pollution by dust event in beijing was very severe. The enrichment factors of S and Cu reached minimums on the dusty days and were high on the non-dusty days. It is considered that enrichment factors of elements in PM2.5, which are associated with human activities, can probably provide an effective method to distinguish local sources from external sources of dust. Factor analysis on the chemical composition in PM2.5 shows that sources of crustal matters, anthropogenic emission, and oil combustion contributed to PM2.5 levels in air in the springtime of 2001 in beijing.

关键词： dust ACE-Asia PM2.5 chemical composition source apportionment.

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RECENT DOMESTIC PROGRESS IN SPACE CRYSTALLIZATION OF PROTEINS

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空间科学学报 1998年第S1期18卷 98-103页

作者： BI Ru-chang (institute of biophysics, The chinese academy of sciences, beijing 100101)

The advances of protein crystal growth in microgravity are limited by its low success rate of space crystallization experiments. Our recent efforts have concentrated on exploration of the ways to increase the success rate of the *** corresponding studies include structural comparisons of space- and Earthgrown protein crystals, numerical simulations of solute transport in protein crystallizer, optimization of protein crystailization conditions and improvement of crystallization techniques used. These studies show that the success rate of space protein crystallization could be improved by different ways.

关键词： Protein Crystal growth Microgravity Success rate of experiments

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Geochemical characteristics of rare earth elements in Wuhan section of the Yangtze River

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Journal of Environmental sciences 1995年第1期7卷 44-51页

作者： Wang Lijun Zhang Shen Zhang Chaosheng(institute of Geography,chinese academy of sciences,beijing 100101,china)Li Xiuxia(institute of High Energy Physics,chinese academy of sciences,beijing 100080,china) Inst of Geog Chinese Academy of Sciences Beijing China China

ＧｅｏｃｈｅｍｉｃａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｉｎＷｕｈａｎｓｅｃｔｉｏｎｏｆｔｈｅＹａｎｇｔｚｅＲｉｖｅｒＷａｎｇＬｉｊｕｎ；ＺｈａｎｇＳｈｅｎ；ＺｈａｎｇＣｈａｏｓｈｅ... 详细信息

ＧｅｏｃｈｅｍｉｃａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｉｎＷｕｈａｎｓｅｃｔｉｏｎｏｆｔｈｅＹａｎｇｔｚｅＲｉｖｅｒＷａｎｇＬｉｊｕｎ；ＺｈａｎｇＳｈｅｎ；ＺｈａｎｇＣｈａｏｓｈｅｎｇ（ＩｎｓｔｉｔｕｔｅｏｆＧｅｏ...

关键词： geochemical characteristics rare earth elements Yangtze River

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Measurement of respiration amount of white birch（Betula platyphylla）population in the mountainous region of beijing

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Journal of Environmental sciences 1995年第4期7卷 391-398页

作者： Fang Jingyun, Wang Xiaoke(Research Center for Eco - Environmental sciences ,chinese academy of sciences, beijing 100085 , china)

Ｍｅａｓｕｒｅｍｅｎｔｏｆｒｅｓｐｉｒａｔｉｏｎａｍｏｕｎｔｏｆｗｈｉｔｅｂｉｒｃｈ（Ｂｅｔｕｌａｐｌａｔｙｐｈｙｌｌａ）ｐｏｐｕｌａｔｉｏｎｉｎｔｈｅｍｏｕｎｔａｉｎｏｕｓｒｅｇｉｏｎｏｆＢｅｉｊｉｎｇＦａｎｇＪｉ... 详细信息

Ｍｅａｓｕｒｅｍｅｎｔｏｆｒｅｓｐｉｒａｔｉｏｎａｍｏｕｎｔｏｆｗｈｉｔｅｂｉｒｃｈ（Ｂｅｔｕｌａｐｌａｔｙｐｈｙｌｌａ）ｐｏｐｕｌａｔｉｏｎｉｎｔｈｅｍｏｕｎｔａｉｎｏｕｓｒｅｇｉｏｎｏｆＢｅｉｊｉｎｇＦａｎｇＪｉｎｇｙｕｎ，ＷａｎｇＸｉａｏｋｅ（...

关键词： diameter distribution mountainous region of beijing respiration white birch population.

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Trophic transfer of mercury and methylmercury in an aquatic ecosystem impacted by municipal sewage effluents in beijing, china

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Journal of Environmental sciences 2010年第8期22卷 1189-1194页

作者： Jianjie Fu, Yawei Wang, Qunfang Zhou, Guibin Jiang State Key laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental sciences, chinese academy of sciences, beijing 100085, china. State Key laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 Chin

Gaobeidian Lake, located in beijing, china, serves as a recipient lake for efluents from a large municipal sewage treatment plant （MSTP）. In order to evaluate the effects of discharging MSTP efluent on the mercury contamination of the local aquatic ecosystem, sediment cores, water, plankton, fish, and turtle samples were collected from Gaobeidian Lake for mercury speciation analysis. High concentrations of total mercury （T-Hg） were detected in sediment cores （5.24–17.0 μg/g dry weight （dw）, average： 10.1 μg/g）. The ratio of methylmercury （MeHg） to T-Hg was less than 0.3% in sediments and ranged from 35% to 76% in biota samples. The highest level of T-Hg and MeHg were found in aquatic bryophyte and crucian carp （3673 and 437 ng/g dw, respectively）. The relative contents of MeHg were significantly correlated with trophic levels （R2 = 0.5506, p 0.001）, which confirmed that MeHg can be bio-transferred and biomagnified via food chain in this aquatic ecosystem.

关键词： methylmercury total mercury trophic levels aquatic ecosystem municipal sewage treatment plants

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Preliminary crystallographic studies on Des-(Phe-Val-Asn)^(B1-3)-insulin

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chinese Science Bulletin 1997年第6期42卷 507-510页

作者： JIN Rongsheng, WAN Zhuli and LIANG DongcaiState Key laboratory of Biomacromolecules, institute of biophysics, chinese academy of sciences, beijing 100101, Chin State Key laboratory of Biomacromolecules Institute of Biophysics Chinese Academy of Sciences Beijing China

THE results of the X-ray analysis of the three-dimensional structure of insulin have shown that, in rhombohedral 2-Zn insulin, the N-terminal segment of the B-chain is on the surface of the monomer and dimmer of insulin molecules, assigning an extended conformation and high flexibility. With the difference of the surrounding solvent circumstances such as the crystallization condition of rhombohedral 4-Zn insulin, its configuration varies significantly: the

关键词： Des-(Phe-Val-Asn)B1-3 -insulin crystal growth X-ray diffraction.

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Reconstruction of temperature series in china for the last 5000 years

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Progress in Natural Science:Materials International 2006年第8期16卷 838-845页

作者： GE Quansheng, WANG Shunbing and ZHENG Jingyun (institute of Geographical sciences and Natural Resources Research, chinese academy of sciences, beijing 100101, china Graduate School of the chinese academy of sciences, beijing 100039, china) institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China. Graduate School of The chinese academy of sciences Beijing 100039 China

A temperature series with a 100 year resolution for the last 5000 years in china has been reconstructed by using 31 longterm temperature proxy series selected from recent publications in the last 20 years. The proxy records include pollens, stalagmites, lake-sediments, peat, ice cores and historical documents. The result reveals that in the millennial scale temperature variation it was warm in 3050-250 BC and it was cold in 250 BC-1950 AD. In the above two periods there were many stages of sub-scale temperature fluctuations. The result also shows an obvious temperature discrepancy on the century to multi-century scale between the Eastern Monsoon Region, the Qinghai-Tibet Region and the Northwestern Region in 2850 BC, 2350 BC, 1350 BC, 950-350 BC, 50-250 AD, and 550 AD. A comparison between the reconstructed series of this paper and some North Hemisphere temperature series indicates that in the longterm scale change, the temperature change in china is in phrase with that of the Northern Hemisphere during the last 5000 years, while on the century to multi-century scale there are differences at the beginning and end times, which may imply that temperature change does not occur simultaneously in different regions.

关键词： temperature series the last 5000 years china.

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PREPARATION AND PROPERTIES OF ETHYL-CYANOETHYL CELLULOSE/POLYACRYLIC ACID COMPOSITE FILMS WITH REFLECTION COLORS

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chinese Journal of Polymer Science 2001年第3期19卷 277-282页

作者： Yong Huang institute of Chemistry, chinese academy of sciences, beijing 100080 china laboratory of Cellulose and Lignocellulosics Chemistry Guangzhou institute of Chemistry chinese academy of sciences, Guangzhou 510650, china 中科院化学所北京

Ethyl-cyanoethyl cellulose [(E-CE)C]/acrylic acid (AA) becomes a cholesteric liquid crystalline solution withvivid colors when the (E-CE)C concentration is 42 wt%～52 wt%. (E-CE)C/polyacrylic acid (PAA) composites withcholesteric structure were prepared by polymerzing AA in (E-CE)C/AA liquid crystalline solutions. The layers of orderedpolymer chains in the cholesteric phase were inclined during polymerization and the degree of the inclination depended onthe polymerization temperature and the concentration of the solution before polymerization. The cholesteric structure in thecomposites could not be changed when temperature was lower than 100℃. Cross-linking of the PAA in compositesimproved their water-resistance. The cholesteric order of the composites without cross-linking was destroyed when theywhere immersed in water. The color derived from the selective reflection of the cholesteric phase of the cross-linkedcomposites turned from blue to red after the composites absorbed water. The color of the composites could be returned to theoriginal one when the absorbed water was removed from the swollen composites.

关键词： Cholesteric structure Composites Selective reflection Liquid crystalline solutions

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