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Impact of dams on flood occurrence of selected rivers in the United States

Frontiers of Earth Science 2017年第2期11卷 268-282页

作者： Xuefei MEI P.h.A.J.M. VAN GELDER Zhijun DAI Zhenghong TANG State Key Laboratory of Estuarine & Coastal Research East China Normal University Shanghai 200062 China Faculty of Technology Policy and Management Delft University of Technology 2628BX Delft the Netherlands Community and Regional Planning Program University of Nebraska-Lincoln Lincoln NE 68588-0105 USA

A significant large number of dams have been constructed in the past two centuries in the United States. These dams＇ ability to regulate downstream flooding has received world-wide attention. In this study, data from 38 rivers distributed over the entire conterminous Untied States with extensive pre- and post-dam annual peak discharge records, were collected to research the impacts of various dams on the flood behaviors at a national scale. The results indicate that dams have led to significant reductions in flood magnitude for nearly all of the sites; the decrease rate in the mean of annual peak discharge varies between 7.4% and 95.14%, except for the Dead River, which increased by 1.46%. Because of dams＇ effective- ness, the probability density curve of annual peak flow changes from a flat to peaked shape because both the range and magnitude of high discharges are decreased. More- over, the potential impact of dams on flood characteristics were closely related to the dam＇s geographic location and function, the ratio of the storage capacity of the dam to the mean annual runoff of the river （C/R）, and the ratio of reservoir storage capacity to the area of its drainage （C/D）. Specifically, the effects of dams on annual peak flows were more related to latitude than longitude. Compared with dams built for other purposes, the dam exclusively used for flood management cut off more flood peaks. Increases in the ratios of C/R and C/D increased the degree of modification of annual maximum discharge.

关键词： flood characteristics river discharge dam,flood modification

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Reflections on 25 Years of Social Science Research Collaboration in China

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Journal of Reproduction and Contraception 2010年第4期21卷 243-250页

作者： Iqbal h.Shah Department of Reproductive health and Research World Health Organization

This paper is to reflect on 25 wonderful years of my collaboration with the Chinese scientists and policy makers on social science and operations research in sexual reproductive health. Past and ongoing collaboration is reviewed, followed by a discussion on the record of achievements and ideas for future directions and research priorities. The paper represents my views based on an exceptionally rich personal and professional experience working with numerous Chinese scientists on a range of research topics.

关键词： Reflections on 25 Years of Social Science Research Collaboration in China

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Damage smear method for rock failure process analysis

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第6期11卷 1151-1165页

作者： G.Li X.F.Cheng h.Pu C.A.Tang state key laboratory of coastal and offshore engineering dalian university of technologydalian116024china state key laboratory for geomechanics and deep underground engineering china university of mining and technologyxuzhou221116china ocean engineering joint research center of dut-uwa dalian university of technologydalian116024china

Damage smear method(DSM)is adopted to study trans-scale progressive rock failure process,based on statistical meso-damage model and finite element *** statistical approach is utilized to reflect the mesoscopic rock *** constitutive law of representative volume element(RVE)is established according to continuum damage mechanics in which double-damage criterion is *** damage evolution and accumulation of RVEs are used to reveal the macroscopic rock failure *** single RVE will be represented by one unique *** initiation,propagation and coalescence of meso-to macro-cracks are captured by smearing failed *** above ideas are formulated into the framework of the DSM and programed into self-developed rock failure process analysis(RFPA)*** laboratory-scale examples are conducted and the well-known engineering-scale tests,*** Energy of Canada Limited’s(AECL’s)Underground Research Laboratory(URL)tests,are used for *** shows that the simulation results match with other experimental results and field observations.

关键词： Failure process Smear method Meso-damage Finite element method (FEM) Rock failure process analysis (RFPA)

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The Uses and Benefits of Big Data for Geological Surveys

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Acta Geologica Sinica(English Edition) 2019年第S1期93卷 64-65页

作者： Michael h.STEPhENSON British Geological Survey NottinghamNG125GGUK

’Long tail’data is the difficult-to-get-at data that sits in libraries,institutes and on the computers of individual *** specialists like to contrast it with the smaller number of large,more accessible data sets(*** et al.,2013).The name’long tail’derives from graphs drawn of the size of data sets against their number:there are relatively few large datasets and a lot of smaller ones.

关键词： long tail data informatics biostratigraphy geological survey

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Duffin-Kemmer-Petiau equation under hartmann ring-shaped potential

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Chinese Physics C 2014年第3期38卷 7-11页

作者： h.hassanabadi M.Kamali Z.Molaee S.Zarrinkamar Physics Department Shahrood University of Technology Department of Basic Sciences Garmsar BranchIslamic Azad University

We solve the DufRn-Kemmer-Petiau（DKP） equation in the presence of hartmann ring-shaped potential in（3＋l）-dimensional *** obtain the energy eigenvalues and eigenfunctions by the Nikiforov-Uvarov（NU）method.

关键词： DKP equation hartmann ring-shaped potential Nikiforov-Uvarov method energy eigenvalue eigenfunctions

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The influence of chlorinated aromatics＇ structure on their adsorption characteristics on activated carbon to tackle chemical spills in drinking water source

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Frontiers of Environmental Science & Engineering 2015年第1期9卷 138-146页

作者： Pengfei LIN Yuan ZhANG Xiaojian ZhANG Chao ChEN Yuefeng XIE Irwin h SUFFET School of Environment Tsinghua University Beijing 100084 China Environmental Programs Pennsylvania State University Middletown PA 17057 USA Department of Environment health Sciences University of California at Los Angeles Los Angeles CA 90095 USA

This study focused on evaluating the efficiency of powdered activated carbon （PAC） adsorption process and tackling chlorobenzenes and chlorophenols spill in drinking water source. The adsorption kinetics and PAC＇s capacities for five chlorobenzenes and three chlorophenols at drinking water contamination levels were studied in order to determine the influence of different functional groups on the adsorption behavior. The results showed that PAC adsorption could be used as an effective emergency drinking water treatment process to remove these compounds. The adsorption kinetics took 30 min to achieve nearly equilibrium and could be described by both pseudo first-order and pseudo second-order models. A mathematic relationship was developed between the pseudo first-order adsorption rate constant, k1, and the solutes＇ properties including lgKow, polarizability and molecular weight. The Freundlich isotherm equation could well describe the adsorption equilibrium behaviors of chlorinated aromatics with r2 from 0.920 to 0.999. The h-bond donor/acceptor group, hydrophobicity, solubility and molecular volume were identified as important solute properties that affect the PAC adsorption capacity. These results could assist water professionals in removing chlorinated aromatics during emergency drinking water treatment.

关键词： chlorinated aromatics adsorption powdered activated carbon kinetics equilibrium

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Simplified Technique for Predicting Offshore Pipeline Expansion

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Journal of Marine Science and Application 2018年第1期17卷 68-78页

作者： J.h.Seo D.K.Kim h.S.Choi S.Y.Yu K.S.Park Graduate School of Engineering Mastership Pohang University of Science and TechnologyPohang 37673Republic of Korea Ocean and Ship Technology Research Group Universiti Teknologi PETRONAS32610 Seri IskandarPerakMalaysia Department of Civil and Environmental Engineering Universiti Teknologi PETRONAS32610 Seri IskandarPerakMalaysia Vietnam Construction Steel Solution Marketing Center POSCO Vietnam HoldingsHo Chi Minh City 700000Vietnam

In this study,we propose a method for estimating the amount of expansion that occurs in subsea pipelines,which could be applied in the design of robust structures that transport oil and gas from offshore *** begin with a literature review and general discussion of existing estimation methods and terminologies with respect to subsea *** to the effects of high pressure and high temperature,the production of fluid from offshore wells is typically caused by physical deformation of subsea structures,e.g.,expansion and contraction during the transportation *** severe cases,vertical and lateral buckling occurs,which causes a significant negative impact on structural safety,and which is related to on-bottom stability,free-span,structural collapse,and many other *** addition,these factors may affect the production rate with respect to flow assurance,wax,and hydration,to name a *** this study,we developed a simple and efficient method for generating a reliable pipe expansion design in the early stage,which can lead to savings in both cost and computation *** such,in this paper,we propose an applicable diagram,which we call the standard dimensionless ratio(SDR)versus virtual anchor length(LA)diagram,that utilizes an efficient procedure for estimating subsea pipeline expansion based on applied reliable *** this user guideline,offshore pipeline structural designers can reliably determine the amount of subsea pipeline expansion and the obtained results will also be useful for the installation,design,and maintenance of the subsea pipeline.

关键词： Pipe expansion hP/hT Thermal expansion Subsea pipeline

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Survey and Analysis of VoIP Frame Aggregation Methods over A-MSDU IEEE 802.11n Wireless Networks

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Computers, Materials & Continua 2021年第2期66卷 1283-1300页

作者： Mosleh M.Abualhaj Abdelrahman h.hussein Manjur Kolhar Mwaffaq Abu Alhija Al-Ahliyya Amman University AmmanJordan Prince Sattam Bin Abdulaziz University Al-KharjSaudi Arabi

The IEEE 802.11n standard has provided prominent features that greatly contribute to ubiquitous wireless *** the last ten years,voice over IP(VoIP)has become widespread around the globe owing to its low-cost or even free call *** combination of these technologies(VoIP and wireless)has become desirable and inevitable for ***,VoIP faces a bandwidth utilization issue when working with 802.11 wireless *** bandwidth utilization is inefficient on the grounds that(i)80 bytes of 802.11/RTP/UDP/IP header is appended to 10–730 bytes of VoIP payload and(ii)765μs waiting intervals follow each 802.11 VoIP *** considering the quality requirements of a VoIP call,be including frame aggregation in the IEEE 802.11n standard has been suggested as a solution for the bandwidth utilization ***,several aggregation methods have been proposed to handle the quality requirements of VoIP calls when carried over an IEEE 802.11n wireless *** this survey,we analyze the existing aggregation methods of VoIP over the A-MSDU IEEE 802.11n wireless *** survey provides researchers with a detailed analysis of the bandwidth utilization issue concerning the A-MSDU 802.11n standard,discussion of the main approaches of frame aggregation methods and existing aggregation methods,elaboration of the impact of frame aggregation methods on network performance and VoIP call quality,and suggestion of new areas to be investigated in conjunction with frame *** survey contributes by offering guidelines to design an appropriate,reliable,and robust aggregation method of VoIP over 802.11n standard.

关键词： VoIP VoIP frame aggregation IEEE 802.11n bandwidth utilization A-MSDU A-MPDU

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ATOMIC　FORCE　MICROSCOPY　OBSERVATION　OF　MAGNETRON　SPUTTERED　ALUMINUM－SILICON　ALLOY　FILMS

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Acta Metallurgica Sinica(English Letters) 1996年第4期9卷 263-266页

作者： J.W.Wu,J.h. Fang and Z.h.Lu (National Laboratory of Molecule and Biomolecule Electronics,Southeast University,Nanjing 210096, China

wo different surface morphology characteristics of magnetron sputtered aluminumsilicon(Al-Si)alloy films deposited at 0 and 200℃ were observed by atomic force microscopy(AFM).One is irregularly shaped grains put togther on a *** other is irregularly shaped grains Piled up in space. Nanometer-sized particles with heights from 1.6 to 2.9 nm were first observed. On the basis of these observations the growth mechanism of magnetron sputtered films is discussed.

关键词： magnetron sputtering Al-Si alloy surface morphology,atomic force microscopy,film growth mechanism

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Welfare and Market Impacts of Food Safety Measures in China: Results from Urban Consumers' Valuation of Product Attributes

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Journal of Integrative Agriculture 2014年第6期13卷 1404-1411页

作者： David L. Ortega h. holly Wang Nicole J. Olynk Widmar Department of Agricultural Foodand Resource EconomicsMichigan State University Department of Agricultural Economics Purdue University

This study provides an economics assessment of various food safety measures in China. A choice experiment approach is used to elicit Chinese consumer preferences for various food safety attributes using data from a 2008 urban consumer survey. An alternative welfare calculation is used to model aggregate market impacts of select food safety measures. Our results show that the largest welfare gains are found in the current government-run certiifcation program. The implementation of a third-party certiifcation system, a traceability network and a product label would generate signiifcant value and would help reduce current system inefifciencies in China. This study builds on previous research and provides an alternative approach for calculating consumer valuation of safety and quality attributes that can be used to estimate aggregate economic and welfare impacts.

关键词： food safety consumer welfare food policy China

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