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Analytical method of Cr stable isotope and its application to water pollution survey

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Chinese Science Bulletin 2010年第7期55卷 664-669页

High Cr(VI) concentration is a potential serious risk to environment and ecologic ***,it is essential to effectively monitor Cr contamination in water systems and scientifically evaluate its evolution trend.A new method of in-situ tracer technique by Cr isotopic analysis for quantitatively estimating Cr-contamination and its regional evolution in natural waters as well as a case application are reported in this *** on documented literatures,an experimental procedure for chemical separation and purification of Cr in water samples and its analytical method for Cr isotopic measurement by thermal ionization mass spectrometry(TIMS) are *** samples collected around a chemical factory in Hubei Province were analyzed by this *** samples showδ53Cr values ranging from-1.7‰to 7.3‰and an elevating trend with an increasing in distance from the sampling site to pollution source.A functional correlation following Rayleigh fractionation law was established between sample'sδ53Cr value and its extent of Cr *** study suggests that Cr isotopic analysis is an effective method to reveal the spatial distribution and its evolution trend of Cr contamination in the regional water *** is thus helpful to assessing the self-purifying ability of local water system according to Cr isotopic fractionation.

关键词：铬(VI) 水污染调查稳定同位素应用同位素分析供水系统演变趋势示踪技术

Durability of Asphalt Mixture in Different Corrosion Solution

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Journal of wuhan University of Technology(Materials Science) 2011年第6期26卷 1200-1204页

作者：陈拴发关博文 key Laboratory for Special Area Highway Engineering of ministry of {2. Chang’an University School of Materials Science and Engineering Chang’an University

The corrosion to asphalt mixture under different kinds of corrosion solution, such as pH=2.solution, pH=12.solution, pH = 12.solution and 10% Na2.O4 solution, was studied. The performance attenuation of asphalt mixture was analyzed under the normal environment and the freeze-thaw environment, and the analysis was given on the sensitivity of the test results to the evaluation index. The experimental results show that the performance of asphalt mixture is attenuated faster under the acidic solution, alkaline solution and sulfate solution. Corrosion factor Kc, freeze-thaw corrosion factor Kf, and freeze-thaw effect factor Kfc are proposed to evaluate asphalt mixture resistance to corrosion in different kinds of corrosion solution. The values of Kc and Kfc decrease with the increasing of corrosion time. The change rule of Kf show that the rate of corrosion is decreased by the action of freeze-thaw in acidic solution and in alkaline solution, but is increased by the action of freeze-thaw in sulfate solution. The microscopic analysis indicates that acid solution reacts with aggregate of asphalt mixture, alkaline solution reacts with asphalt cement of asphalt mixture, the surface tension of sulfate solution and crystallization of sulfate are the main reasons which weak the performance of asphalt mixture.

关键词： asphalt mixture corrosion damage corrosion mechanism corrosion evaluation

Effect of Fly Ash and Early Strength Agent on Durability of Concrete Exposed to the Cyclic Sulfate environment

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Journal of wuhan University of Technology(Materials Science) 2010年第6期25卷 1065-1069页

作者：袁晓露李北星 key Laboratory of Silicate Materials Science and Engineering of ministry of {2. Wuhan University of Technology

The effect of fly ash and early strength agent on resistance of concrete to the cyclic sulfate environment was *** specimens made with ordinary portland cement or ordinary portland cement incorporating fly ash with the replacement of 10% or 2.%,or 1% early strength agent and fly ash with the replacement of 2.%,were made and subjected to 2.0 cycles of exposure to the cyclic sulfate *** properties including loss of mass,chloride ion diffusion coefficient,compressive strength and flexural strength were *** and chemical component of samples were determined by means of X-ray diffraction,scanning electron microscopy and energy dispersive *** experimental results indicated that effect of fly ash on the cyclic sulfate resistance of concretes was mostly dependent on the amount of fly *** strength agent improved performances of concrete with 2.% fly ash exposed to cyclic sulfate environment.

关键词： fly ash early strength agent durability concrete cyclic sulfate environment

Research on the slope spectrum of the Loess Plateau

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Science china(Technological Sciences) 2008年第S1期51卷 175-185页

作者： TANG GuoAn,LI FaYuan,LIU XueJun,LONG Yi & YANG Xin key Laboratory of Virtual Geographic environment,Nanjing Normal University,{2. of education,Nanjing 2.0046,china Nanjing Normal Univ Key Lab Virtual Geog Environm Minist Educ Nanjing 210046 Peoples R China

A new concept dealing with digital analysis of loess terrain,slope spectrum,is presented and discussed in this paper,by introducing its characteristic,represen-tation and extracting method from DEMs. Using 48 geomorphological units in dif-ferent parts of the loess as test areas and 5 m-resolution DEMs as original test data,the quantitative depiction and spatial distribution of slope spectrum in china's Loess Plateau have been studied on the basis of a series of carefully-designed experiments. In addition,initial experiment indicates a strong relationship between the slope spectrum and the loess landform types,displaying a potential importance of the slope spectrum in geomorphological studies. Based on the slope spectrums derived from the 2. m-resolution DEM data in whole loess terrain in northern part of Shaanxi,13 slope spectrum indices were extracted and integrated into a compre-hensive layer with image integration method. Based on that,a series of unsuper-vised classifications was applied in order to make a landform classification in northern Shaanxi Loess Plateau. Experimental results show that the slope spec-trum analysis is an effective method in revealing the macro landform features. A continuous change of slope spectrum from south to north in northern Shaanxi Loess Plateau shows an obvious spatial distribution of different loess landforms. This also proves the great significance of the slope spectrum method in describing the terrain roughness and landform evolution as well as a further understanding on landform genesis and spatial distribution rule of different landforms in the Loess Plateau.

关键词： Loess Plateau slope spectrum slope DEM loess landform

Carbon distribution and fluxes of 16 rivers discharging into the Bohai Sea in summer

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Acta Oceanologica Sinica 2011年第3期30卷 43-54页

作者： XIA Bin ZHANG Longjun key Laboratory of Marine environmental Science and Ecology Ministry of Education Ocean University of China Qingdao 266100 China key Laboratory of Sustainable Utilization of Marine Fisheries Resources Ministry of Agriculture Yellow Sea Fisheries Research Institute Chinese Academy of Fisheries Sciences Qingdao 266071 China

Riverine carbon input is closely related to the inshore aquatic environment, the marine carbon pool and climate change. Samples were synchronously obtained from 16 rivers discharging into the Bohai Sea （china） in 1-5 July 2.05. The dissolved organic carbon （DOC） concentrations of the 16 rivers were mainly controlled by anthropogenic activities. The particulate organic carbon （POC） of the Haihe, Luanhe, Ziyaxinhe, Chaobaixinhe, Xiaoqinghe, Xiaolinghe, Duliujianhe, Jiyunhe, and Majiahe Rivers mainly originated from pollutants discharged by human, while that of the Huanghe River （Yellow River）, Daliaohe, Shuangtaizihe, Tuhaihe, Dalinghe, Daqinghe, and Liuguhe Rivers were generated mainly by soil erosion. Higher dissolved inorganic carbon （DIC） concentrations in the 16 rivers were detected, which were influenced by the large amounts of carbonate and industrial pollution. The estimated DOC, POC and DIC fluxes from the 16 rivers discharging into the Bohai Sea in summer, 2.05 were 0.91×10^5, 1.2.×10^5 and 6.31×10^5t, respectively.

关键词： Bohai Sea carbon fluxes dissolved organic carbon particulate organic carbon carbon cycling sources

Orthogonal design for optimization of pigment extraction from surface sediments of the Changjiang River Estuary

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Acta Oceanologica Sinica 2011年第4期30卷 33-42页

作者： ZHAO Jun YAO Peng YU Zhigang Thomas S Bianchi key Laboratory of Marine environment and Ecology Ministry of Education Ocean University of China Qingdao 266100 China Department of Oceanography Texas A ＆ M University College Station TX 77843 USA key Laboratory of Marine Chemistry Theory and Technology Ministry of Education Ocean University of China Qingdao 266100 China Institute of Marine Organic Geochemistry College of Chemistry and Chemical Engineering Ocean University of China Qingdao 266100 China

Using a suitable solvent for extracting pigments from sediment for high performance liquid chromatography（HPLC） analysis is critical for obtaining qualitative and quantitative estimates of phytoplanktonic and benthic algal biomass,as well as community composition. Five methodological factors（sample dehydration,extraction solvent,extraction duration,number of extractions,and ratio of solvent volume：sample weight） were studied using an L 9（3 4 ） orthogonal design in a sedimentary pigment extraction experiment on samples collected from the Changjiang large-river delta-front estuary（LDE）,using HPLC analysis. The results show that the optimal extraction method for sedimentary pigments should include freeze-drying samples prior to extraction. The effects of different factors on sedimentary pigment extraction were separated by the L 9（3 4 ） orthogonal design experiments and showed that the extraction solvent was the most important,with extraction duration the second most important,and numbers of extraction and ratio of solvent volume：sample weight was the least important. The mixed solvent treatment comprised of acetone,methanol and water（80：15：5,by volume） was best for polar pigment extraction,with 100% acetone better for apolar pigments. For most pigments employed in this study（i.e.,peridinin,fucoxanthin,alloxanthin,diatoxanthin,zeaxanthin,pheophytin-a and β-carotene） ,3 h was found to be enough time for extraction from these deltaic sediments. However,for chlorophyll-a,the most important pigment used for estimating algal biomass,12.h was needed. A small amount of solvent（3 ml） with duplicate extractions obtained the greatest amount and diversity of pigments. Unfortunately,no extraction method was found to be suitable for all pigments in sediments. The choice of extraction procedure should be made in accordance with the objective of each study,taking into consideration the properties of sediments and pigments in question.

关键词： sedimentary pigments extraction orthogonal design HPLC Changjiang River Estuary

The effects of hydrodynamic conditions on geotechnical strength of the sediment in Yellow River Delta

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International Journal of Sediment Research 2011年第3期26卷 318-330页

作者： JIA Yong-Gang,LIU Xiao-Lei,SHAN Hong-Xian,ZHENG Jie-Wen,and HUO Su-Xia 1 Prof.,Corresponding author,3 Prof.,key Laboratory of Marine environment and Ecology,{2. of education, china Institute of Genenvironmental Engineering,College of environmental Science & Engineering,Ocean University of china,Songlinglu 2.8,Qingdao 2.6100,china, 2.Ph.D.student,key Laboratory of Marine environment and Ecology,{2. of education,Songlinglu 2.8, Qingdao 2.6100,china, 4,5 Ph.D.student,key Laboratory of Marine environment and Ecology,{2. of education,Songlinglu 2.8, Qingdao 2.6100,china, [a]Prof. Corresponding author [b]Ph.D. student Key Laboratory of Marine Environment and Ecology Ministry of Education Songlinglu 238 Qingdao 266100 China [c]Prof. Key Laboratory of Marine Environment and Ecology Ministry of Education China Institute of Genenvironmental Engineering College of Environmental Science & Engineering Ocean University of China Songlinglu 238 Qingdao 266100 China [d]Ph.D. student Key Laboratory of Marine Environment and Ecology Ministry of Education Songlinglu 238 Qingdao 266100 China [e]Ph.D. student Key Laboratory of Marine Environment and Ecology Ministry of Education Songlinglu 238 Qingdao 266100 China

Coastal structures in tidal estuaries are of scientific and societal interest as they form important artificial sea barriers resulting in different hydrodynamic conditions on both sides of them.A field study was performed on both sides of an embankment in the Yellow River Delta,china,in order to investigate the temporal and spatial variations in the geotechnical strength of the sediment caused by the effects of different hydrodynamic *** a portable core penetration tester together with hydrodynamic observation and fractal dimension analyses,changes in sediment strength were tested in 1999 and 2.02.in rectangular areas on both sides of the embankment and along two cross-shore *** field observations both on space and time scales suggest that different intensity in wave loading can not change the mean strength of the superficial sediment within 0-15cm depth,but rather makes it more uneven under strong hydrodynamic conditions,with the increasing degree of heterogeneity that can be quantitatively described by the fractal *** effect of waves is regarded as the major control factor on the quasi-periodic alternation of sediment strength within the study area surface and the depth stratification in the Yellow River *** work is still necessary to determine the forming process,its mechanism and their implications for efficient environmental management,coastal protection and hazard forecasting.

关键词： Sediment strength Heterogeneity Hard layer Hydrodynamic action Intertidal zone Yellow River Delta

Guided wave propagation in multilayered piezoelectric structures

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Science china(Physics,Mechanics & Astronomy) 2009年第7期52卷 1094-1104页

作者： GUO YongQiang1, CHEN WeiQiu2.3 & ZHANG YongLiang4 1 key Laboratory of Mechanics on Disaster and environment in Western{2., ministry of education, and School of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000,{2. 2.key Laboratory of Soft Soils and Geoenvironmental Engineering, ministry of education, and Department of Civil Engineering, Zhejiang University, Hangzhou 310058,{2. 3 Department of Engineering Mechanics, Zhejiang University, Hangzhou 31002.,{2. 4 School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070,{2. key Laboratory of Mechanics on Disaster and environment in Western{2. Ministry of Education and School of Civil Engineering and Mechanics Lanzhou University Lanzhou 730000 China key Laboratory of Soft Soils and Geoenvironmental Engineering Ministry of Education and Department of Civil Engineering Zhejiang University Hangzhou 310058 China Department of Engineering Mechanics Zhejiang University Hangzhou 310027 China School of Civil Engineering Lanzhou Jiaotong University Lanzhou 730070 China

A general formulation of the method of the reverberation-ray matrix (MRRM) based on the state space formalism and plane wave expansion technique is presented for the analysis of guided waves in multilayered piezoelectric structures. Each layer of the structure is made of an arbitrarily anisotropic piezoelectric material. Since the state equation of each layer is derived from the three-dimensional theory of linear piezoelectricity, all wave modes are included in the formulation. Within the framework of the MRRM, the phase relation is properly established by excluding exponentially growing functions, while the scattering relation is also appropriately set up by avoiding matrix inversion operation. Consequently, the present MRRM is unconditionally numerically stable and free from computational limitations to the total number of layers, the thickness of individual layers, and the frequency range. Numerical examples are given to illustrate the good performance of the proposed formulation for the analysis of the dispersion characteristic of waves in layered piezoelectric structures.

关键词： multilayered piezoelectric structures the method of reverberation-ray matrix guided waves dispersion characteristic

Quenched moderate deviations principle for random walk in random environment

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Science china Mathematics 2010年第8期53卷 1947-1956页

作者： HONG WenMing 1 & WANG HuaMing 1,2.1 key Laboratory of Mathematics and Complex Systems of ministry of {2. & School of Mathematical Sciences,Beijing Normal University,Beijing 100875,china 2.Department of Basic Courses,Business College,Beijing Union University,Beijing 10002.,china 1. key Laboratory of Mathematics and Complex Systems of ministry of {2. & School of Mathematical Sciences Beijing Normal University Beijing 100875 China2. Department of Basic Courses Business College Beijing Union University Beijing 100025 China

We derive a quenched moderate deviations principle for the one-dimensional nearest random walk in random environment,where the environment is assumed to be stationary and *** approach is based on hitting time decompos... 详细信息

关键词： random walk in random environment moderate deviations principle hitting time