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哥伦比亚电力系统中发电机的无功能力试验

国外大电机 2015年第1期 15-20页

作者： h.m.SANChEZ

当今电力系统面临着越来越多的来自各方的压力，其中包括电网扩大的困难，用电需求不断增长，及缺乏适宜的调整构架来鼓励新的输配电工程的投资。在哥伦比亚，这种现象迫使电力系统接近极限运行，因此主要的公用电力公司和独立系统操作... 详细信息

当今电力系统面临着越来越多的来自各方的压力，其中包括电网扩大的困难，用电需求不断增长，及缺乏适宜的调整构架来鼓励新的输配电工程的投资。在哥伦比亚，这种现象迫使电力系统接近极限运行，因此主要的公用电力公司和独立系统操作者（Xm）开始立项来确定主要发电机的实际动态和静态无功能力。一旦这项工作完成，基于完整的电力系统模型的电网规划和安全评价将会对发电机提供电压支持和电力系统稳定性的实际能力给出更好的确认。一年多以来，专业委员会研究了发电机无功功率的产出和吸收，掌握了构成同步发电机出力曲线的不同限值，其中包括转子绕组、定子铁心、辅机系统以及发电机稳定性所要求的限值，最终提出一个具体的协议用于无功能力试验。此协议有两个主要的目的：通过识别发电机实际的安全运行区域来重新定义出力曲线，并按照所划定的标准来调节过励和欠励限制器，使之与出力曲线一致。通过定义欠励和过励限制器调节标准，可以使发电机组吸收和产出最多的无功功率，而无需要降低发电机及其相关设备的安全性和整体性。了解发电机实际吸收和产出无功功率能力的一个直接获益是因为维持电压而发电所带来的运行成本的降低。也就是说，如果发现一组发电机的无功能力超出了起初申报的值，那么因为有过剩的无功发电能力，对该地区要求的最少联网发电量计算值会减少。另一个收益是改善了电网规划，现在更接近电力系统的实际运行条件，减少了高成本的无功资源设备的购买，并且由于了解了电力系统的实际需求，减小了电压跌落的风险。最近已在两座电厂按照该协议进行了试验，一个是1200mW的水电厂，另一个是790mW的火电厂，证明了其一致性和可信性。目前，此协议已被用作全哥伦比亚所有中央调度发电机进行此类试验的通用协议和“标准”。本文描述了该协议的形成过程，以及表明其在电力系统中适用性的现场试验结果。考虑到发电机控制有效模型的可用性，并预计相量测量单元在哥伦比亚电力系统中的广泛应用，有望在不久的将来可以根据并网的全部机组的实际出力曲线实现运行点的实时监测。这样，电厂运行人员不再担心机组运行在重新定义的实际出力曲线中的不同点，并且有助于电力系统运营者掌握每个时刻无功功率的实际储备量。通过此信息还可以实时了解电压稳定性的裕度，并且在需要的时候采取预防措施。

关键词：无功功率实际出力曲线过励磁限制器(OEL) 欠励限制器(UEL) 励磁系统自动电压调整器(AVR) 稳定性限制

Deformation Characteristics and Tectonic Evolution of the Eastern Qinling Orogenic Belt

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Acta Geologica Sinica(English Edition) 1986年第3期 23-35页

作者： m.mattauer Ph.matte J.malavieille P.Tapponnier h.maluski Department des Sciences de la Terre Equipe Tectonique Université des Sciences et Techniques du Languedoc Place E. Bataillon 34060 montpellier Cédex France. Department des Sciences de la Terre Equipe Tectonique Université des Sciences et Techniques du Languedoc Place E. Bataillon 34060 Montpellier Cédex France.Department des Sciences de la Terre Equipe Tectonique Université des Sciences et Techniques du Languedoc Place E. Bataillon 34060 Montpellier Cédex France.Institut de Physique du Globe 4 Place Jussieu 75230 Paris Cedex 05 France.Department des Sciences de la Terre Equipe Tectonique Université des Sciences et Techniques du Languedoc Place E. Bataillon 34060 Montpellier Cédex France.

The Qinling mountains separating the northern from the southern China plate is a key region for the study of structural evolution of eastern Asia. It is composed of the Palaeozoic fold belt in its northern part and the Variscan and Indosinian fold belts in its southern part. The evolution of the former is marked by the closure of a northward subducting oceanic basin in the early stage, followed by southward obduction of ophiolites and intracontinental thrusting during the Variscan; whereas that of the latter is represented by intracontinental, shallow crustal deformation on the basis of a large-scale detachment structure(with a horizontal slip of at least of 100 km). Since the late Palaeozoic, however, both of the belts have been cut by a series of east-west sinistral strike-slip faults.

关键词： Deformation Characteristics and Tectonic Evolution of the Eastern Qinling Orogenic Belt

mODELING DIURNAL AND LONG-TERm NUTRIENT DYNAmICS IN TASIK hARAPAN mALAYSIA

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MODELING DIURNAL AND LONG-TERM NUTRIENT DYNAMICS IN TASIK HA...

Characteristics and Outcomes of Coronavirus Disease 2019 (COVID-19) Infection among Children Admitted in Al-Imam Abdulrahman Al Faisal hospital in Riyadh, Saudi Arabia

第三世界生态高峰会

作者： h.L.Koh S.Y.Teh.m.mansor A.m.I.Izani D.L.DeAngelis School of math.matical Sciences ISchool of Biological Sciences Universiti Sains malaysia 11800 Pulau Pinang malaysia. Department of Biology University of miami USA

Previous studies conducted on Lake harapan in Universiti Sains malaysia main campus in Penang malaysia have identified algae and nutrients as the main parameters contributing towards poor water quality in the *** oxygen(DO)can fluctuate wildly over the diurnal cycle due to photosynthesis and respiration,reaching a high of 15 mg/L around 5 to 6 pm and a low of almost zero at about 5 to 6 am in the *** low DO has resulted in episodic fish kill,while the high levels of algae(330 mg/l of Chl a)reduce the aesthetic value of the *** the lake has been in operation for the past 15 years as a flood retention pond without any desludging,sediment accumulated

关键词： Sediment photosynthesis model

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Open Journal of Pediatrics 2021年第2期11卷 170-178页

作者： Abdullah h. Alh.moud hareth A. Aldosaimani Abdullah A. Alyahya Ahmad K. Almadani Nabil h. madkhali Laila m. Alali Ibrah.m A. Alsahabi Department of Laboratory Al-Imam Abdulrahman Al-Faisal Hospital First Health Cluster Ministry of Health Riyadh Saudi Arabia Department of Pediatrics Al-Imam Abdulrahman Al-Faisal Hospital First Health Cluster Ministry of Health Riyadh Saudi Arabia Department of health.management Al-Imam Abdulrahman Al-Faisal Hospital First Health Cluster Ministry of Health Riyadh Saudi Arabia Collage of medicine Jazan Univerisity Jazan Saudi Arabia

Background: At the beginning of the COVID-19 pandemic, some reports demonstrated that children are at lower risk of infection. Though, with the growing transmission of the virus, it has been illustrated that it can infect children. Nevertheless, the features and outcomes of COVID-19 infection in children are still unclear. Objective: This study aims to describe the clinical characters and outcomes of children infected with COVID-19 and admitted to a hospital in Saudi Arabia. Design and Setting: This is a retrospective study that was carried out in Imam Abdulrahman Al Faisal Hospital in Riyadh, Saudi Arabia, by collecting data from patients’ records of children who were admitted to the hospital from March to July 2020. The collected data included information on the age and gender of the children, as well as their clinical course during hospitalization. Results: Thirty-three patients were included;39.4% of the children aged less than one year, 51.5% were males. Asthma occurred in 15.2% of patients. Asthma (p-valuemil

关键词： COVID-19 Clinical Outcomes Children Characters mortality Saudi Arabia

Effects of forced aeration on community dynamics of free and attached bacteria in copper sulphide ore bioleaching

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International Journal of minerals,metallurgy and materials 2022年第1期29卷 59-69页

作者： Wei Chen Shenghua Yin I.m.S.K.Ilankoon Key Laboratory of ministry of Education for high-Efficient mining and Safety of metal University of Science and Technology BeijingBeijing 100083China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China Discipline of Ch.mical Engineering School of EngineeringMonash UniversityJalan Lagoon SelatanBandar SunwaySelangor Darul Ehsan 47500Malaysia

Bacterial community dynamics and copper leaching with applied forced aeration were investigated during low-grade copper sulphide bioleaching to obtain better bioleaching *** illustrated that appropriate aeration improved bacterial concentrations and leaching *** highest bacterial concentration and Cu^(2+)concentration after 14-d leaching were 7.61×10^(7) cells·mL^(−1) and 704.9 mg·L^(−1),respectively,at aeration duration of 4 h·d^(−1).The attached bacteria played a significant role during bioleaching from 1 to 7 ***,free bacteria dominated the bioleaching processes from 8 to 14 *** phenomenon was mainly caused by the formation of passivation layer through Fe3+hydrolysis along with bioleaching,which inhibited the contact between the attached bacteria and ***,16S rDNA analysis verified the effect of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans on the bioleaching *** results demonstrate the importance of free and attached bacteria in bioleaching.

关键词： attached bacteria bioleaching forced aeration free bacteria low-grade copper sulphide ore

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Algorithms of Confidence Intervals of WG Distribution Based on Progressive Type-II Censoring Samples

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Journal of Computer and Communications 2017年第7期5卷 101-116页

作者： moh.med A. El-Sayed Fathy h. Riad m. A. Elsafty Yarub A. Estaitia Department of math.matics Faculty of Science Fayoum University Fayoum Egypt Department of Computer Science College of Computers and IT Taif University Taif KSA Department of math.matics Faculty of Science Minia University Minia Egypt Department of math.matics Faculty of Science Aljouf University Aljouf KSA Department of math.matics and Statistics Faculty of Science Taif University Taif KSA

The purpose of this article offers different algorithms of Weibull Geometric (WG) distribution estimation depending on the progressive Type II censoring samples plan, spatially the joint confidence intervals for the parameters. The approximate joint confidence intervals for the parameters, the approximate confidence regions and percentile bootstrap intervals of confidence are discussed, and several markov chain monte Carlo (mCmC) techniques are also presented. The parts of mean square error (mSEs) and credible intervals lengths, the estimators of Bayes depend on non-informative implement more effective than the maximum likelihood estimates (mLEs) and bootstrap. Comparing the models, the mSEs, average confidence interval lengths of the mLEs, and Bayes estimators for parameters are less significant for censored models.

关键词： Algorithms Simulations Point Estimation Confidence Intervals Bootstrap Approximate Bayes Estimators mCmC mLEs

基于脱钩理论的贵州省建设占用耕地与经济增长关系数据与分析

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全球变化数据学报（中英文） 2019年第1期3卷 59-68,168-177页

作者：刘青山陈浒陈静王存璐李林芝杨乙未张红梅国家喀斯特石漠化防治工程技术研究中心/贵州师范大学喀斯特研究院/中国南方喀斯特生态环境学科创新引智基地/贵州省喀斯特山地生态环境省部共建国家重点实验培育基地贵阳550001

为了探讨贵州省建设占用耕地与经济协调发展之间的关系,利用贵州省2007–2016共10年的统计数据,选取建设占用耕地量与非农GDP产值两个重要指标,运用脱钩系数模型并参考相关研究成果对贵州省耕地占用与经济发展之间的关系进行实证研究,... 详细信息

为了探讨贵州省建设占用耕地与经济协调发展之间的关系,利用贵州省2007–2016共10年的统计数据,选取建设占用耕地量与非农GDP产值两个重要指标,运用脱钩系数模型并参考相关研究成果对贵州省耕地占用与经济发展之间的关系进行实证研究,得到贵州省建设占用耕地与经济增长分析数据集。数据结果表明,2007–2016年贵州省建设占用耕地与经济发展的脱钩关系曲线总体呈"m"型变化;脱钩状态依次表现出波动调整期、过渡平稳期和波动调整期共三个时期的动态过程;脱钩状态类型中耕地保护和经济发展状况最好的时期,即强脱钩类型占到统计周期的33.33%,贵州省的经济发展一直保持着理想的良性循环发展状态。数据集包括以下内容:(1)2007–2016年贵州省非农GDP变化率;(2)2007–2016年贵州省建设占用耕地量与经济增长脱钩指标分析数据。数据集存储为1个Excel文件(.xlsx格式),数据量为14.2 KB。

关键词：经济耕地占用脱钩分析贵州省农业

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The Vascular Vegetation Populating the Flora in Building materials of historic monuments Cities of the West Central Region of morocco

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Open Journal of Ecology 2014年第9期4卷 565-570页

作者： Bouamar Baghdad A.Taleb A.Carlo Inigo Inigo h.El hadi m.Dalimi Department Natural Resources and Environment Agronomic and Veterinary Institute-Hassan ⅡRabatMorocco Instituto de Recursos Naturales y Agrobiologia de Salamanca(IRNASA) Consejo Superior de Investigaciones Cientificas(CSIC)SalamancaSpain Laboratory of Applied Geology Geomatics and EnvironmentFaculty of Science of Ben M’SikHassan Ⅱ UniversityCasablancaMorocco Department of Ch.mistry Faculty of Science and TechnologyUniversity Hassan ⅡMohammediaMorocco

In the concern of the preservation of the main historic monuments of the cities of Rabat and Sale (morocco), a botanical study was conducted in 2009. The prospecting of these monuments allowed raising an inventory of the flora populating their building materials, and it has proved that this flora is rich and diversified. Indeed, it consists of 171 adventitious species distributed in 46 botanical families. The most represented families are Asteraceae, Poaceae, Fabaceae, Caryophyllaceae, Geraniaceae, Brassicaceae and Lamiaceae. They supply, to th.m only 49.7% of the specific size. The annual therophytes and the dicotyledon are dominant with respectively 66.7% and 84.7% of the specific size. Nevertheless, the presence of more than 20 species of trees and perennials constitutes a serious danger for bulwarks walls, especially by the phenomenon of fissuring by the action of the huge roots of these vegetables. These vegetables fitting into are placed on joints or cracks fissures have a ch.mical action on stones by acids that they release, and also a mechanical action by the growth of roots inside cracks fissures. They remain one of these are one of the important biological factors of the degradation of historic monuments. It is to note that the bulwarks walls of the site of Chella (Roman ruins) present more floral diversity than the other canvassed monuments (91 species) that are 53% of the total size.

关键词： Degradation historic monuments Building materials Flora morocco

基于DWI的腹膜转移功能性肿瘤负荷可预测晚期卵巢癌不完全肿瘤减灭

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国际医学放射学杂志 2020年第6期 751-752页

作者：刘晨 E.Y.P.Lee h.An J.A.U.Perucho K.W.h.Chiu E.S.hui m.m.Y.Chu h.Y.S.Ngan Department of Diagnostic Radiology Queen Mary Hospital University of Hong Kong

摘要目的探讨基于DWI的腹膜转移(PC)量化评估在判断卵巢癌(OC)不完全肿瘤减灭中的预测价值。方法术前前瞻性纳入疑似Ⅲ-Ⅳ期或复发性OC病人行DWI检查。采

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