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Experimental study of the flow field of a high head model pump turbine based on PIV technique

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Journal of Hydrodynamics 2021年第5期33卷 1045-1055页

作者： De-min liu Wei-lin Xu Yong-zhi Zhao State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China Dongfang Electric Machinery Co. LtdDeyang 618000China

Pumped storage units are the main parts in China’s power construction,as a hot issue concerned by the *** pump turbine involves the two-way flows and a multiple condition operation,and its operation flow pattern is very *** particle image velocimetry(PIV)is a very effective test technique to determine the internal flow field of pump *** paper discusses the key problems of the pump turbine,based on the PIV experiments under typical conditions of the pump turbine,especially for problems such as the S-shape problem,the hump problem,the pressure fluctuation problem and the cavitation *** the internal flow fields under typical conditions are *** vortices induced and their development are observed in the PTV *** flow phenomenon is shown at each operating *** typical problems of the pump turbine are closely related to the vortex distribution in the internal flow *** the PIV test results under several working conditions and from the comparisons between the optimal condition and the part load condition,it is seen that the vortex distributions are very *** at the vane-less area between the guide vane and the runner are closely related to the strong pressure pulsation,the first hump and the S-shape *** the PIV results of the cavitation working points,it is seen that the flow angle is changed in the vane-less region and the runner leading edge because of the cavitation bubbles and that the flow angle deviates from the optimal setting *** the computational fluid dynamics(CFD)result of the second hump working points,it is concluded that the vortex shedding on the runner leading edge is the main cause of the second hump.

关键词： Pump turbine particle image velocimetry(PIV) pressure pulsation pump hump cavitation four quadrants curve

Construction of Optimal Mixed-Level Uniform Designs

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Journal of Systems Science & Complexity 2024年第2期37卷 841-862页

作者： CHATTERJEE Kashinath liu min-Qian QIN Hong YANG liuqing Department of Population Health Sciences Division of Biostatistics and Data ScienceAugusta UniversityGA 30912USA NITFID LPMC&KLMDASRSchool of Statistics and Data ScienceNankai UniversityTianjin 300071China School of Statistics and Mathematics Zhongnan University of Economics and LawWuhan 430073China

The theory of uniform design has received increasing interest because of its wide application in the field of computer *** generalized discrete discrepancy is proposed to evaluate the uniformity of the mixed-level factorial *** this paper,the authors give a lower bound of the generalized discrete discrepancy and provide some construction methods of optimal mixed-level uniform designs which can achieve this lower *** methods are all deterministic construction methods which can avoid the complexity of stochastic *** saturated mixed-level uniform designs and supersaturated mixed-level uniform designs can be obtained with these ***,the resulting designs are also χ^(2)-optimal and minimum moment aberration designs.

关键词： Generalized discrete discrepancy Hadamard matrix mixed-level design orthogonal array supersaturated design

Repelling effects of Mg on diffusion of He atoms towards surface in SiC: Irradiation and annealing experiments combined with first-principles calculations

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Journal of Advanced Ceramics 2023年第12期12卷 2284-2299页

作者： min liu Qiqi Li Jun Hui Yongfeng Yan Renduo liu Biao Wang Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China School of Materials Science and Engineering Dongguan University of TechnologyDongguan 523000China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China

In this study,the effects of Mg on the formation of He bubbles and diffusion behavior of He atoms in cubic silicon carbide(3C–SiC)were investigated by irradiation and annealing experiments as well as first-principles *** results indicated that two damage bands were formed in He&Mg irradiated *** annealing,Mg could prevent He atoms from diffusing to the surface,resulting in the formation of the He bubbles in the deeper areas far from Mg-implanted regions,which is helpful in avoiding surface ***-principles calculations were then performed to explore the effects of Mg on the He behavior in *** solution energy,binding energy charge density,bond length,and crystal orbital Hamiltonian population of these elements were calculated to identify their *** results suggested that the binding capacity between He and Mg was weak,and Mg could increase the diffusion energy barrier of *** initio molecular dynamics(AIMD)simulation showed that Mg could make He in a high-energy unstable state,and force He atom to move toward the vacancy away from Mg,which explains the experimental results.

关键词： SiC irradiation He bubbles Mg ab initio molecular dynamics(AIMD)

Overexpression of StCYS1 gene enhances tolerance to salt stress in the transgenic potato(Solanum tuberosum L.)plant

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Journal of Integrative Agriculture 2020年第9期19卷 2239-2246页

作者： liu min-min LI Ya-lun LI Guang-cun DONG Tian-tian liu Shi-yang liu Pei WANG Qing-guo Key Laboratory of Food Processing Technology and Quality Control in Shandong Province College of Food Science and EngineeringShandong Agricultural UniversityTai'an 271018P.R.China Institute of Vegetables and Flowers Chinese Academy of Agricultural Sciences/Key Laboratory of Biology and Genetic Improvement of Tuber and Root CropMinistry of Agriculture and Rural AffairsBeijing 100081P.R.China

Salt stress seriously restricts the growth and yield of *** cystatins are vital players in biotic stress and development,however,their roles in salt stress resistance remain ***,we report that StCYS1 positively regulates salt tolerance in potato *** in vitro biochemical test demonstrated that StCYS1 is a bona fide *** of StCYS1 in both Escherichia coli and potato plants significantly increased their resistance to high *** analysis revealed that the transgenic plants accumulated more proline and chlorophyll under salt stress ***,the transgenic plants displayed higher H2O2 scavenging capability and cell membrane integrity compared with wild-type *** results demonstrate that StCYS1 is closely correlated with salt stress and its overaccumulation can substantially enhance salt stress resistance.

关键词： potato salt stress cystatin StCYS1 overexpression

2022 Multiple-country Monkeypox Outbreak and Its Importation Risk into China:An Assessment Based on the Risk Matrix Method

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Biomedical and Environmental Sciences 2022年第10期35卷 878-887页

作者： DU min ZHANG Shi Mo SHANG Wei Jing YAN Wen Xin liu Qiao QIN Chen Yuan liu min liu Jue Department of Epidemiology and Biostatistics School of Public HealthPeking UniversityBeijing 100191China Institute for Global Health and Development Peking UniversityBeijing 100871China Global Center for Infectious Disease and Policy Research&Global Health and Infectious Diseases Group Peking UniversityBeijing 100191China

Objective To analyze the 2022 multiple-country monkeypox outbreak and assess its importation risk into *** Data was from United States Centers for Disease Control and *** described the global epidemic and calculated concentration index to measure economic-related *** risk into China was evaluated and ranked by using risk matrix method and Borda count method,*** As of July 29,2022,of 79 countries or territories,39(49.37%,39/79),17(21.52%,17/79),6(7.59%,6/79),12(15.19%,12/79),and 5(6.33%,5/79)country or territories identified cases1,*** were economic-related health disparities exist in the distribution of cases(the concentration index=0.42,P=0.027),and the inequality disadvantageous to the rich(pro-poor).There were 12(15.38%,12/78),15(19.23%,15/78),6(7.69%,6/78),and 45(57.69%,45/78)countries or territories with extremely high,high,moderate,and low importation *** States and France ranked first with the highest Borda points of 156,and counts of *** Of 78 countries or territories,the key attention need be paid to the United States and France,*** the epidemic progresses,preparing prevention and control measures to further reduce importation risk was crucial.

关键词： Monkeypox Importation risk China Risk matrix method

Positional and Quantitative Characterization of the Hydroxyethyl Groups in Hydroxyethyl Starch by GC/MS or NMR

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Chinese Chemical Letters 2002年第11期13卷 1097-1099页

作者： Ye min liu Gui Yun XU Center for Molecular Science Institute of ChemistryChinese Academy of SciencesBeijing 100080

The position and quantity of the hydroxyethyl groups in hydroxyethyl starch (HES) were studied by GC/MS and NMR. Quantitative characterization was carried out based on the results of both methods.

关键词： Hydroxyethyl starch GC/MS NMR.

Fuzzy Shape Control Based on El man Dynamic Recursion Network Prediction Model

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Journal of Iron and Steel Research International 2006年第1期13卷 31-35页

作者： JIA Chun-yu liu Hong-min College of Mechanical Engineering Yanshan University Qinhuangdao 066004 Hebei China

In the strip rolling process, shape control system possesses the characteristics of nonlinearity, strong coupling, time delay and time variation. Based on self adapting Elman dynamic recursion network prediction model, the fuzzy control method was used to control the shape on four-high cold mill. The simulation results showed that the system can be applied to real time on line control of the shape.

关键词： shape prediction shape control Elman dynamic recursion network parameter self-adjusting fuzzy control

Hydrogenic-Donor Impurity States in GaAs/Al xGa 1−xAs Quantum Dots in the Presence of an Electric Field

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Chinese Physics Letters 2011年第8期28卷 217-220页

作者： PAN Jiang-Hong liu Li-Zhe liu min College of Physical and Technology Guangxi Normal UniversityGuilin 541004

We report a calculation of binding energy of the ground state of a hydrogenic donor in a quantum cylindrical GaAs dot surrounded by Ga1−xAlxAs with finite confinement potentials,in the presence of a uniform electric field applied parallel to the dot *** binding energy increases inchmeal as the radius of the dot decreases until a maximum value for a certain value of the quantum dot radii,then begins to drop *** for the binding energies and electronic wave function density of the hydrogenic-donor as functions of the impurity position,dot thickness and applied electric field are also presented.

关键词： donor quantum radius

Application of an Integrated Risk Matrix and the Borda Count Method on Lassa Fever in Assessing the Importation Risk of EID — 9 African Countries, 1996–2023

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China CDC weekly 2024年第44期6卷 1152-1158页

作者： Weijing Shang Yu Wu Jue liu Wannian Liang min liu School of Public Health Peking UniversityBeijingChina Vanke School of Public Health Tsinghua UniversityBeijingChina.

Introduction:Common methods for assessing and responding to outbreaks of emerging infectious diseases(EIDs)are usually applied in isolation and have *** study aimed to integrate the risk matrix and Borda count methods to assess the importation risk of EIDs to China,using Lassa fever(LF)as an ***:This study used a mixed-methods approach combining multi-source data with an integrated risk matrix and Borda count *** were obtained from the World Health Organization,the Concise Statistics of International Students dataset,the United Nations World Tourism Organization,and the Statistical *** risk was assessed across two dimensions:possibility and *** importation risk was then categorized into 4 levels(low,moderate,high,and extremely high),corresponding to green,yellow,orange,and red zones,respectively,in the risk matrix assessment *** Borda count method was used to rank the ***:The importation risk for 9 countries that experienced LF outbreaks from 1996 to 2023 was scored and ranked by importation possibility and severity to derive overall importation *** study determined that Nigeria posed the highest LF importation risk to China,ranking first among West African countries with the highest Borda *** with moderate importation risk included Sierra Leone,Burkina Faso,and ***:An integrated risk matrix and Borda count method presented in this study may serve as a significant supplement to other risk assessment methods and enrich the current toolbox of public health countermeasures and inform future risk management of the importation of EIDs.

关键词： EID orange dimensions