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Estimation methods of eco-environmental water requirements: Case study

Science china Earth Sciences 2005年第8期48卷 1280-1292页

作者： yang Zhifeng1,2. CUI Baoshan1 & LIU Jingling 1. School of Environment, beijing Normal {2., beijing 100875, china 2. state key Joint Laboratory of Environmental Simulation and Pollution control, beijing 100875, china 1. School of Environment Beijing Normal University 100875 Beijing China 2. state key Joint Laboratory of Environmental Simulation and Pollution {2. 100875 Beijing China

Supplying water to the ecological environment with certain quantity and quality is significant for the protection of diversity and the realization of sustainable development. The conception and connotation of eco-environmental water requirements, including the definition of the conception, the composition and characteristics of eco-environmental water requirements, are evaluated in this paper. The classification and estimation methods of eco-environmental water requirements are then proposed. On the basis of the study on the Huang-Huai-Hai Area, the present water use, the minimum and suitable water requirement are estimated and the cor-responding water shortage is also calculated. According to the interrelated programs, the eco-environmental water requirements in the coming years (2.10, 2.30, 2.50) are estimated. The result indicates that the minimum and suitable eco-environmental water requirements fluc-tuate with the differences of function setting and the referential standard of water resources, and so as the water shortage. Moreover, the study indicates that the minimum eco-environmental water requirement of the study area ranges from 2.84×1010m3 to 1.02.1011m3, the suitable water requirement ranges from 6.45×1010m3 to 1.78×1011m3, the water shortage ranges from 9.1×109m3 to 2.16×1010m3 under the minimum water requirement, and it is from 3.07×1010m3 to 7.53×1010m3 under the suitable water requirement. According to the different values of the water shortage, the water priority can be allocated. The ranges of the eco-environmental water re-quirements in the three coming years (2.10, 2.30, 2.50) are 4.49×1010m3?1.73×1011m3, 5.99×10m3?2.09×1011m3, and 7.44×1010m3?2.52.1011m3, respectively.

关键词： eco-environmental water requirements, assessment methods, Huang-Huai-Hai area.

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Experiments and sensitivity analyses for heat transfer in a meter-scale regularly fractured granite model with water flow

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Journal of Zhejiang university-Science A(Applied Physics & Engineering) 2012年第12期13卷 958-968页

作者： wei LU1,2.Yan-yong XIANG1 (1School of Civil Engineering,beijing jiaotong university,{2.,china) (2.4} key Laboratory of Simulation and Regulation of Water Cycle in River Basin,china Institute of Water Resources and Hydropower Research,beijing 100038,china) 1. School of Civil Engineering Beijing Jiaotong University Beijing 100044 China 2. state key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower Research Beijing 100038 China

Experiments of saturated water flow and heat transfer were conducted for a meter-scale model of regularly fractured granite. The fractured rock model （height 1502.5 ram, width 904 mm, and thickness 300 mm）, embedded with two vertical and two horizontal fractures of pre-set apertures, was constructed using 18 pieces of intact granite. The granite was taken from a site currently being investigated for a high-level nuclear waste repository in china. The experiments involved different heat source temperatures and vertical water fluxes in the embedded fractures either open or filled with sand. A finite difference scheme and computer code for calculation of water flow and heat transfer in regularly fractured rocks was developed, verified against both the experimental data and calculations from the TOUGH2.code, and employed for parametric sensitivity analyses. The experiments revealed that, among other things, the temperature distribution was influenced by water flow in the fractures, especially the water flow in the vertical fracture adjacent to the heat source, and that the heat conduction between the neighboring rock blocks in the model with sand-filled fractures was enhanced by the sand, with larger range of influence of the heat source and longer time for approaching asymptotic steady-state than those of the model with open fractures. The temperatures from the experiments were in general slightly smaller than those from the numerical calculations, probably due to the fact that a certain amount of outward heat transfer at the model perimeter was unavoidable in the experiments. The parametric sensitivity analyses indicated that the tem- perature distribution was highly sensitive to water flow in the fractures, and the water temperature in the vertical fracture adjacent to the heat source was rather insensitive to water flow in other fractures.

关键词： Fractured granite Water flow Heat transfer Physical modeling Numerical calculation Sensitivity analysis

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QAAS:quick accurate auto-scaling for streaming processing

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Frontiers of Computer Science 2024年第1期18卷 5-15页

作者： Shiyuan LIU Yunchun LI Hailong yang Ming DUN Chen CHEN Huaitao ZHANG wei LI state key Laboratory of Software Development Environment Beijing 100191China School of Computer Science and Engineering Beihang UniversityBeijing 100191China School of Cyber Science and Technology Beihang UniversityBeijing 100191China School of Computer Science and Technology Xi’an Jiaotong UniversityXi’an 710049China

In recent years,the demand for real-time data processing has been increasing,and various stream processing systems have *** the amount of data input to the stream processing system fluctuates,the computing resources required by the stream processing job will also *** resources used by stream processing jobs need to be adjusted according to load changes,avoiding the waste of computing *** present,existing works adjust stream processing jobs based on the assumption that there is a linear relationship between the operator parallelism and operator resource consumption(e.g.,throughput),which makes a significant deviation when the operator parallelism *** paper proposes a nonlinear model to represent operator *** divide the operator performance into three stages,the Non-competition stage,the Non-full competition stage,and the Full competition *** our proposed performance model,given the parallelism of the operator,we can accurately predict the CPU utilization and operator *** with actual experiments,the prediction error of our model is below 5%.We also propose a quick accurate auto-scaling(QAAS)method that uses the operator performance model to implement the auto-scaling of the operator parallelism of the Flink *** to previous work,QAAS is able to maintain stable job performance under load changes,minimizing the number of job adjustments and reducing data backlogs by 50%.

关键词： stream processing performance model auto-scaling

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AFM study on the adsorption and aggregation behavior of dissolved humic substances on mica

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Science china Chemistry 2006年第3期49卷 256-266页

作者： GE Xiaopeng1, ZHOU Yanmei2. Lü Chunhua1 & TANG Hongxiao1 1. state key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, {2. 100085, china 2. School of Civil Engineering & Architecture, beijing jiaotong university, beijing 100044, china 1. state key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China 2. School of Civil Engineering & Architecture Beijing Jiaotong University Beijing 100044 China

Humic substances constitute the major organic fractions of soils, sediments and natural waters, and play a dominant role in the binding, mobilization, transport and ultimate fate of organic contaminants in subsurface systems. In this paper, two humic acid samples, Guanting and Tianjin, with different origin and chemical compositions have been investigated with AFM imaging for their adsorption and aggregation behaviors on mica. While the Tianjin humic sample is found to form small spheres with 2.0 to 330 nm in diameter at lower concentrations, irregular loop-chain assemblies of hundreds of nanometer in diameter with the chain width of about 40 nm are dominant for the Guanting humic sample, which may attribute to the more polar aliphatic fractions in the chemical composition in the latter. The heterogeneous and polydisperse nature of humic substances with multiple structural features, such as sponge-like structures, perforated sheets, aggregate of spheres, branches and chain-like assemblies etc., is apparent at higher concentrations for both humic samples, showing morphologically new evidence for the dominant view of the humic dual-mode sorption model. With naphthalene introduced, the assemblies of Guanting humic substances clearly become more compact with significantly narrowed branches and less porous the perforated sheet-like structures. It is indica- tive of that smaller nanometer scale rings present along the perforated assemblies could potentially represent hydrophobic domains, which may facilitate the adsorption and aggregation of naphthalene onto the natural particle surfaces and therefore lead to an important role of dissolved humic sub- stances in the sorption of environmental pollutants.

关键词： atomic force microscopy (AFM) dissolved humic substances morphology aggregation adsorption

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Distribution Line Longitudinal ProtectionMethod Based on Virtual Measurement Current Restraint

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Energy Engineering 2024年第2期121卷 315-337页

作者： weiWang yang Yu Simin Luo Wenlin Liu wei Tang Yuanbo Ye Power Dispatching control Center State Grid Anhui Electric Power Co.Ltd.Hefei230022China School of Electrical Engineering Beijing Jiaotong UniversityBeijing100044China

As an effective approach to achieve the“dual-carbon”goal,the grid-connected capacity of renewable energy increases *** are the most widely used renewable energy sources and have been applied on various ***,the inherent randomness,intermittency,and weak support of grid-connected equipment not only cause changes in the original flow characteristics of the grid but also result in complex fault *** overcurrent and differential protection methods cannot respond accurately due to the effects of unknown renewable energy ***,a longitudinal protection method based on virtual measurement of current restraint is proposed in this *** positive sequence current data and the network parameters are used to calculate the virtual measurement current which compensates for the output current of photovoltaic(PV).The waveform difference between the virtual measured current and the terminal current for internal and external faults is used to construct the protection *** improved edit distance algorithm is proposed to measure the similarity between virtual measurement current and terminal measurement ***,the feasibility of the protection method is verified through PSCAD simulation.

关键词： Photovoltaic interconnection distribution network longitudinal protection method edit distance algorithm

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Experimental study on drying of typical MSW under incinerator-like conditions

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Science china(Technological Sciences) 2007年第5期50卷 636-643页

作者： ZHANG yanguo1, CHEN MeiQian2. MENG AiHong1, LI QingHai1 & CHEN YunXuan2.1 key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua {2., beijing 100084, china 2.School of Mechanical, Electronical and control Engineering, beijing jiaotong university, beijing 100044, china 1. key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University Beijing 100084 China 2. School of Mechanical Electronical and Control Engineering Beijing Jiaotong University Beijing 100044 China

In this paper, a series of experiments were conducted to investigate the drying of typical municipal solid wastes (MSW) in a muffle incinerator. From the experimental drying characteristic curves, the effects of temperature on drying process were observed to be more obvious in the low temperature region than in the high tem- perature region in muffle incinerator. At a specified drying temperature, drying time was highly dependent upon the packed waste thickness, having an exponent rela- tion with the thickness. When the drying temperature increased or the thickness of potato bulks was diminished, the maximum drying rate reduced. Based on the first-order reaction, activation energy (Ea), and factor A of potato and cabbage were determined.

关键词： drying, MSW, potato blocks, cabbage stems, temperature, dying rate

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Micromechanical analysis of interaction energy for SMA reinforced composite

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Science china(Technological Sciences) 2009年第3期52卷 610-616页

作者： ZHU YuPing1,2. DUI GuanSuo1 & DUO Liu3 1 Institute of Mechanics, beijing jiaotong university, beijing 100044, {2. 2.Department of Engineering Mechanics, Jiangsu university, Zhenjiang 2.2.13, {2. 3 state key Lab of Crystal Materials, Shandong university, Jinan 2.0100, {2. Institute of Mechanics Beijing Jiaotong University Beijing 100044 China Department of Engineering Mechanics Jiangsu University Jiangsu Zhenjiang 212013 China state key Lab of Crystal Materials Shandong University Jinan 250100 China

The energy of the interaction between the matrix and the inclusions in shape memory alloy (SMA) re- inforced composite is one of the most important and complicated parts in thermodynamic constitutive theory. In this paper, the interaction energy is derived based on the classical theory of micromechanics and the thermodynamic theory. The SMA composite is treated as three phases, namely the austenitic phase, the martensite phase and the matrix phase. The interaction among the three phases is analyzed in a way close to the fact. The present expression is used to calculate the interaction energy of a typical SMA composite with attentions paid to understand of the effects of the matrix material, the fiber ge- ometry, and the fiber/matrix volume ratio. It is shown that the method developed in this paper is credible compared with the references. Some useful conclusions are obtained.

关键词： shape memory alloy interaction energy SMA composite micromechanics thermodynamics

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Time trends and disparities of obesity and related national policies and programs in Nepal:a systematic review

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Global Health Journal 2024年第2期8卷 46-57页

作者： Junxiang wei Peng Nie Liwang Gao yang Mi Youfa Wang Department of Obstetrics Northwest Women's and Children's HospitalXi'anShaanxiChina School of Economics and Finance Xi'an Jiaotong UniversityXi'anShaanxiChina Center for Non-Communicable Disease Management Beijing Children's HospitalCapital Medical UniversityNational Center for Children's HealthBeijingChina Global Health Institute No.21 Hongren BuildingWest China Science and Technology lnnovation Harbour(iHarbour)Xi'anShaanxiChina School of Public Health Xi'an Jiaotong UniversityXi'anShaanxiChina

Objective Overweight and obesity prevalence has increased in low-income *** study systematically reviewed the obesity trend,disparities,and prevention and control efforts in *** We searched PubMed and Google Scholar for articles and reports published between January 1,2.04 and December 31,*** information on National policies and programs related to obesity prevention was retrieved from governmental websites and consultation with relevant *** and obesity were defined using the World Health Organization body mass index cut ***-two studies and reports were *** Overall,overweight and obesity rates increased in all groups in Nepal although nationally representative data remained *** combined overweight and obesity(OW/OB)and obesity rates in women aged 15-49 years increased from 8.5%to 2..2.and from 0.9%to 5.1%between 2.06 and 2.16,***/OB and obesity rates in men were 17.1%and 2.5%based on data from the 2.16 Demographic and Health ***/OB rate in under-five children increased from 0.6%to 2.8%between 2.06 and *** rates for school-age(5-9 years)boys and girls in 2.16 were 2.4%and 2.8%,respectively,and were 1.1%and 1.4%for male and female adolescents aged 10-19 years,***/OB prevalence was much higher among women,residents in urban areas and central provinces,and in higher socioeconomic status *** prevalence of OW/OB and obesity for 2.30 in adults aged 15-49 was 44.7%and 8.3%,respectively,while it was 2.2.for OW/OB in preschool *** and direct interventions that specifically focused on obesity prevention and control are *** OW/OB prevalence in Nepal has increased during the past 1.8 decades,disproportionately affecting population *** interventions mostly focused on undernutrition with some indirect implications for obesity *** the future,Nepal needs to develop population-based programs for obesity

关键词： Nutrition transition Overweight Obesity Obesity prevention Systematic review Nepal

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Rumen metagenome reveals the mechanism of mitigation methane emissions by unsaturated fatty acid while maintaining the performance of dairy cows

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Animal Nutrition 2024年第3期18卷 296-308页

作者： Zhantao yang Yuhui Zheng Siyuan Liu Tian Xie Qianqian Wang Zhonghan Wang Shengli Li wei Wang state key Laboratory of Animal Nutrition and Feeding Beijing Engineering Technology Research Center of Raw Milk Quality and Safety ControlCollege of Animal Science and TechnologyChina Agricultural UniversityBeijing 100193China

Dietary fat content can reduce the methane production of dairy cows;however,the relevance fatty acid(FA)composition has towards this inhibitory effect is ***,in-depth studies elucidating the effects of unsaturated fatty acids(UFA)on rumen function and the mechanism of reducing methane(CH4)production are *** study exposed 10 Holstein cows with the same parity,similar milk yield to two total mixed rations:low unsaturated FA(LUFA)and high unsaturated FA(HUFA)with similar fat *** LUFA group mainly added fat powder(C16:0>90%),and the HUFA group mainly replaced fat powder with extruded *** experiment lasted 2. d,the last 5 d of which,gas exchange in respiratory chambers was conducted to measure gas *** found that an increase in the UFA in diet did not affect milk production(P>0.05)and could align the profile of milk FAs more closely with modern human nutritional ***,we found that increasing the UFA content in the diet lead to a decrease in the abundance of Methanobrevibacter in the rumen(|linear discriminant analysis[LDA]score|>2.and P 2.and P<0.05),which ultimately decreased CH4 production(P<0.05).Our results illustrated the mechanism involving decreased CH4 production when fed a UFA diet in dairy *** believe that our study provides new evidence to explore CH4 emission reduction measures for dairy cows.

关键词： Methane emission Rumen metagenome Dairy cow Unsaturated fatty acid

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Optimization of Processing Parameters for Laser Powder Deposition using Finite Element Method

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Journal of Wuhan university of Technology(Materials Science) 2010年第5期25卷 832-837页

作者：付垚 state key Laboratory of Non-ferrous Metals and Processes General Research Institute for Non-ferrous Metals

In order to investigate the effects of powder materials and processing parameters on thermal and stress field during laser powder deposition （LPD）, a finite element model was developed with the help of ANSYS software. The finite element model was verified by the comparison between the experimental results and computed results. Then LPD processes with different powder materials and processing parameters were simulated by using the FE model. The results show that less difference of thermal conductivity and thermal expansion coefficient between powder material and substrate material produces lower residual stress; higher laser power, laser scanning speed and smaller laser beam diameter can lead higher peak temperature and higher residual stress. The research opens up a way to rational selection of the powder materials and processing parameters for ensured quality.

关键词： laser powder deposition thermal field stress field powder material processing parameters

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