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ANALYSIS OF THE PREDICTION CAPABILITY OF WEB SEARCH DATA BASED ON THE HE-TDC METHOD - PREDICTION OF THE VOLUME OF DAILY TOURISM VISITORS

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Journal of Systems Science and Systems Engineering 2017年第2期26卷 163-182页

作者： Geng Peng Ying Liu Jiyuan Wang jifa Gu School of Economic and Management University of Chinese Academy of Sciences Beijing 100190 China Key Laboratory of Big Data Mining and Knowledge Management Chinese Academy of Sciences Beijing 100190 China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

Web search query data are obtained to reflect social spots and serve as novel economic indicators. When faced with high-dimensional query data, selecting keywords that have plausible predictive ability and can reduce dimensionality is critical. This paper presents a new integrative method that combines Hurst Exponent （HE） and Time Difference Correlation （TDC） analysis to select keywords with powerful predictive ability. The method is called the HE-TDC screening method and requires keywords with predictive ability to satisfy two characteristics, namely, high correlation and fluctuation memorability similar to the predicting target series. An empirical study is employed to predict the volume of tourism visitors in the Jiuzh.i Valley scenic area. The study shows that keywords selected using HE-TDC method produce a model with better robustness and predictive ability.

关键词： Tourism visitor volume prediction web-search data HE-TDC method Jiuzh.i Valley,time series Hurst exponent

On limiting behavior of stationary measures for stochastic evolution systems with small noise intensity

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Science China Mathematics 2020年第8期63卷 1463-1504页

作者： Lifeng Chen zh.o Dong jifa Jiang Jianliang zh.i Mathematics and Science College Shanghai Normal UniversityShanghai 200234China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China Wu Wen-Tsun Key Laboratory of Mathematics University of Science and Technology of ChinaHefei 230026China

The limiting behavior of stochastic evolution processes with small noise intensityεis investigated in distribution-based ***μεbe a stationary measure for stochastic process Xεwith smallεand X0 be a semiflow on a Polish *** that{με:0<ε≤ε0}is *** all their limits in the weak sense are X0-invariant and their supports are contained in the Birkhoff center of *** are made to various stochastic evolution systems,including stochastic ordinary differential equations,stochastic partial differential equations,and stochastic functional differential equations driven by Brownian motion or Levy processes.

关键词： stationary measure Lyapunov function limit measure support Birkhoff center stochastic evolution system

Master equation,design equations and runaway speed of the Kaplan turbine

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Journal of Hydrodynamics 2021年第2期33卷 282-300页

作者： zh.zh.ng zh.W Zurch University of Applied ScienceZurichSwitzerland

To make the Kaplan turbine technology comparable to both the Pelton and the Francis turbine,the master equation for the Kaplan turbine has been established by analyses similar to that-for the Francis *** analysis begins with the descriptions of free vortex flows at the runner inlet and the swirl flow at the impeller *** considering the Euler equation for specific work and by further evaluating the most significant shock and swirling losses,the first and the second energy equations in the form of hydraulic efficiency were *** master equation is then established by combining both energy *** addition,three design equations and a new design parameter are *** master equation relates the turbine hydromechanics to the geometrical design of both the runner and the guide-vane *** enables the complete hydraulic characteristics of a given Kaplan turbine to be analytically and simply computed.A computation example demonstrates the functionality and applicability of the *** the reconstructed master equation,the runaway speed of the Kaplan turbine and its dependence on the guide-vane setting can be easily and precisely *** bulb turbines with guide vanes directly ahead of the turbine runner in the same tube,all computations are also applicable using another equivalent control parameter.

关键词： Kaplan turbine master equation design equations design parameter runaway speed hydraulic efficiency shock loss swirling loss bulb turbines

Manufacture of HTR Fuel Element

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High Technology Letters 1995年第1期1卷 87-90页

作者： Shijiang, X. Chunhe, T. zh.chang, X. Junguo, zh. Xueliang, Q. Ende, L. Tsinghua Univ Beijing China

The HTR Fuel Element R & D Program,set in 1987,aims to develop the manufacturetechnology of HTR fuel element and to produce the fuel element for the first core of our 10MW experimental *** the work on laboratory scale... 详细信息

关键词： High temperature reactor Coated fuel particles Spherical fuel element Irradiation qualification

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“如果”句功能的类型学考察

汉语学习 2024年第2期 22-32页

作者：吴炳章姜彩璨许冰中国海洋大学外国语学院山东青岛266100

“如果”句的语义结构和用法复杂多样,但学界对该结构的功能类型分析过于笼统。文章通过语料库梳理书面语中“如果”句的结构特点和语篇关系,对其进行了功能分类。从功能视角看,“如果”句在知识域、语言域和人际域中分别发挥前提限定... 详细信息

“如果”句的语义结构和用法复杂多样,但学界对该结构的功能类型分析过于笼统。文章通过语料库梳理书面语中“如果”句的结构特点和语篇关系,对其进行了功能分类。从功能视角看,“如果”句在知识域、语言域和人际域中分别发挥前提限定、语篇建构和会话修辞等功能。根据从句和主句的意义关系,“如果”句可以分为蕴含条件句和非蕴含条件句。各类“如果”句的功能各有句法语义特征。从各类“如果”句的用法分布看,“如果”句的主要功能是表达推理关系,其次是语篇关系,再次是话语修辞。

关键词： “如果”句假设条件句间接条件句

Master equation and runaway speed of the Francis turbine

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Journal of Hydrodynamics 2018年第2期30卷 203-217页

作者： zh.zh.ng Free Researcher Zurich Switzerland

The master equation of the Francis turbine is derived based on the combination of the angular momentum（Euler） and the energy laws. It relates the geometrical design of the impeller and the regulation settings（guide vane angle and rotational speed） to the discharge and the power output. The master equation, thus, enables the complete characteristics of a given Francis turbine to be easily computed. While applying the energy law, both the shock loss at the impeller inlet and the swirling loss at the impeller exit are taken into account. These are main losses which occur at both the partial load and the overloads and, thus, dominantly influence the characteristics of the Francis turbine. They also totally govern the discharge of the water through the impeller when the impeller is found in the standstill. The computations have been performed for the discharge, the hydraulic torque and the hydraulic efficiency. They were also compared with the available measurements on a model turbine. Excellent agreement has been achieved. The computations also enable the runaway speed of the Francis turbine and the related discharge to be determined as a function of the setting angle of the guide vanes.

关键词： Francis turbine master equation runaway speed hydraulic efficiency shock loss swirling loss streamline similarity method

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Journal of Hydrodynamics 2018年第1期30卷 140-152页

作者： zh.zh.ng Free Researcher Zurich Switzerland

An analytical method is presented, which enables the non-uniform velocity and pressure distributions at the impeller inlet of a pump to be accurately computed. The analyses are based on the potential flow theory and the geometrical similarity of the streamline distribution along the leading edge of the impeller blades. The method is thus called streamline similarity method（SSM）. The obtained geometrical form of the flow distribution is then simply described by the geometrical variable G（s） and the first structural constant G_Ⅰ. As clearly demonstrated and also validated by experiments, both the flow velocity and the pressure distributions at the impeller inlet are usually highly non-uniform. This knowledge is indispensible for impeller blade designs to fulfill the shockless inlet flow condition. By introducing the second structural constant G_Ⅱ, the paper also presents the simple and accurate computation of the shock loss, which occurs at the impeller inlet. The introduction of two structural constants contributes immensely to the enhancement of the computational accuracies. As further indicated, all computations presented in this paper can also be well applied to the non-uniform exit flow out of an impeller of the Francis turbine for accurately computing the related mean values.

关键词： Pumps streamline similarity method flow distribution shock loss structural constant

血清RDW、NT-proBNP水平联合检测对老年急性心力衰竭患者发生MACE的预测价值

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淮海医药 2024年第2期42卷 142-146页

作者：荆娇莹朱继法张晓河南省新郑市公立人民医院心血管内科 451100 郑州大学第一附属医院心内一科河南郑州450000

目的:分析急性心力衰竭(AHF)患者红细胞分布宽度(RDW)、氨基末端B型脑钠肽前体(NT-proBNP)水平及与心功能分级的相关性,探讨二者联合检测对AHF患者发生主要不良心血管事件(MACE)的预测价值。方法:选取某院2018年2月—2020年9月收治的136... 详细信息

目的:分析急性心力衰竭(AHF)患者红细胞分布宽度(RDW)、氨基末端B型脑钠肽前体(NT-proBNP)水平及与心功能分级的相关性,探讨二者联合检测对AHF患者发生主要不良心血管事件(MACE)的预测价值。方法:选取某院2018年2月—2020年9月收治的136例AHF患者为AHF组,选取同期90例慢性心力衰竭(CHF)患者为CHF组,同期100例健康体检者为健康组,比较三组NT-proBNP、RDW水平。比较不同心功能分级AHF患者血清NT-proBNP、RDW水平及与心功能分级的相关性。随访1年,根据AHF患者是否发生MACE,评估血清RDW、NT-proBNP水平联合检测对AHF患者发生MACE的预测价值。结果:AHF组血清RDW、NT-proBNP水平[(16.79±1.82)%、(6086.22±973.74)pg/mL]高于CHF组[(14.86±1.32)%、(3168.57±875.69)pg/mL]和健康组[(12.81±0.73)%、(128.96±33.64)pg/mL],差异均有统计学意义(P<0.05)。Ⅱ级、Ⅲ级、Ⅳ级AHF患者血清RDW分别为(14.67±0.56)%、(17.62±0.74)%、(19.27±0.46),血清NT-proBNP分别为(5715.64±784.31)pg/mL、(6234.45±850.53)pg/mL、(6512.39±913.03)pg/mL,随着AHF患者心功能分级增加,血清RDW、NT-proBNP水平逐渐升高,差异均有统计学意义(P<0.05)。心功能分级与血清RDW(r=0.607)、NT-proBNP(r=0.614)水平呈正相关(P<0.05)。发生MACE的AHF患者血清RDW、NT-proBNP水平[(18.46±1.63)%、(6481.70±754.38)pg/mL]高于未发生MACE的AHF患者[(16.47±1.42)%、(6009.90±669.75)pg/mL](P<0.05);血清RDW、NT-proBNP水平联合检测预测AHF患者发生MACE的AUC、敏感度、特异度分别为0.944、90.91%、88.60%(P<0.001)。结论:老年AHF患者血清RDW、NT-proBNP处于较高水平,其水平变化与AHF患者心功能分级呈正相关,二者联合检测对AHF患者发生MACE具有较高的预测价值。

关键词：急性心力衰竭红细胞分布宽度氨基末端B型脑钠肽前体主要不良心血管事件

Conflicting selection pressures on seed size and germination caused by carnivorous seed dispersers

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Integrative Zoology 2023年第5期18卷 799-816页

作者： jifa CUI Yaqian zh.NG Jinyu GUO Nan WU Youbing zh.U Engineering Research Center of Eco-environment in Three Gorges Reservoir Region Ministry of EducationChina Three Gorges UniversityYichangChina

Plants produce nutritious,fleshy fruits that attract various animals to facilitate seed dispersal and recruitment ***-specific differential selection of seed size by multiple frugivorous disperser assemblages may affect the subsequent germination of the ingested ***,there is little empirical evidence supporting this *** the present study,we documented conflicting selection pressures exerted on seed size and germination by five frugivorous carnivores on a mammal-dispersed pioneer tree,the date-plum persimmon(Diospyros lotus),in a subtropical *** analyses revealed that these carnivores acted as primary seed dispersers of *** also observed that seed sizes were selected based on body mass and were species-specific,confirming the“gape limitation”hypothesis;three small carnivores(the masked palm civet Paguma larvata,yellow-throated marten Martes flavigula,and Chinese ferret-badger Melogale moschata)significantly preferred to disperse smaller seeds in comparison with control seeds obtained directly from wild plants whereas the largest Asiatic black bears(Ursus thibetanus)ingested larger *** dispersed by medium-sized hog badgers(Arctonyx albogularis)were not significantly different from control ***,regarding the influence of gut passage on seed germination,three arboreal dispersal agents(martens,civets,and bears)enhanced germination success whereas terrestrial species(ferret-badgers and hog badgers)inhibited the germination process compared with undigested control *** conflicting selection pressures on seed size and germination may enhance the heterogeneity of germination dynamics and thus increase species fitness through diversification of the regeneration *** results advance our understanding of seed dispersal mechanisms and have important implications for forest recruitment and ecosystem dynamics.

关键词： fleshy fruit gut treatment seed germination seed size selection pressure