检索结果-南通市图书馆

Voidage correction method for DEM study of 3D pebble flows in a bed of cycloidal base

在线全文

学校读者我要写书评

暂无评论

PARTICUOLOGY 2024年第10期93卷 30-40页

作者： xia, Zirui Shi, Minglei Zou, Quan Gui, Nan Yang, Xingtuan Tu, Jiyuan Jiang, Shengyao Tsinghua Univ Inst Nucl & New Energy Technol Collaborat Innovat Ctr Adv Nucl Energy Technol Key Lab Adv Reactor Engn & SafetyMinist Educ Beijing 100084 Peoples R China Tsinghua Univ Dept Engn Phys Beijing 100084 Peoples R China Tsinghua Univ Dept Automat Beijing 100084 Peoples R China RMIT Univ Sch Engn Melbourne Vic 3083 Australia

Voidage (porosity or void fraction) in packed particles (or pebbles) is of fundamental importance in calculating the pressure drop, obtaining the drag, predicting the bed permeability, estimating the neutron streaming, etc. For the case when particles are deformed, a method of voidage correction during the packing state is proposed using a Discrete Element Method (DEM) simulation of 3D pebble flow inside a bed of cycloidal base. A function to evaluate the remaining volume of a pebble intercepted by horizontal and vertical planes is proposed for voidage calculation. After that, the process of solving voidage distribution is provided in detail. Using this method, the voidage inside the cycloidal-base pebble bed is obtained to refer to reported similar data for validation. This method can be potentially used for dynamical voidage calculation in CFD-DEM simulation which can get suitable voidage distribution after the correction. (c) 2024 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

关键词： Voidage Pebble flow Packed bed Discrete element method Cycloidal base KD-Tree Volume correction RADIAL POROSITY GAS MODEL SIMULATION PACKINGS SPHERES

Generating Baikal-GVD high energy cascade-like neutrino events with a GEANT4-based simulation toolkit

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第10期48卷 256-263页

作者： Zike Wang A.D.Avrorin zhen Cao Mingjun Chen Peiyuan Chu zh.-A.M.Dzhilkibaev Bo Gao Tianqi Huang Jiali Liu Ying Qi xiaohao You D.N.Zaborov Key Laboratory of Particle Astrophysics Experimental Physics Division&Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China Institute for Nuclear Research of the Russian Academy of Sciences Moscow 117312Russia TIANFU Cosmic Ray Research Center Chengdu 610213China School of Science Tibet UniversityLhasa 850000China

Using the GEANT4 and Cosmic Ray Monte Carlo(CRMC)software packages,we developed a new simulation toolkit for astrophysical neutrino *** configuring the Baikal-GVD detector and comparing the vertex position and direction of incident particles,as well as the channel-by-channel signals,to the events detected by Baikal-GVD,we successfully generated 13 high-energy cascade neutrino events with the *** analysis revealed a systematic offset between the reconstructed shower position and the true interaction position,with a distance close to the scale of the shower maximum of−0.54±1.29 *** achieved a good linear relationship between the photoelectron number of neutrino events obtained by simulation and the real data measured by *** simulation toolkit could serve as a reliable basis for studying the performance of astrophysical neutrino telescopes.

关键词： high-energy neutrino cascade event simulation Cherenkov

老年心力衰竭患者血浆脑钠肽前体质量浓度与QTc间期关系及对预后的预测

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国组织工程研究与临床康复 2007年第16期11卷 3055-3057页

作者：张建义黄文新阳跃中潘迪华莫新玲夏中华徐彤彤桂林医学院附属医院心内科广西壮族自治区桂林市541001

目的:分析老年充血性心力衰竭患者血浆脑钠肽前体与QTc间期的关系、以及二者对充血性心力衰竭预后的判断价值。方法:选择2003-05/2005-07在桂林医学院附属医院心内科住院的充血性心力衰竭患者208例[年龄(66.1±13.5)岁]。①使用罗氏201... 详细信息

目的:分析老年充血性心力衰竭患者血浆脑钠肽前体与QTc间期的关系、以及二者对充血性心力衰竭预后的判断价值。方法:选择2003-05/2005-07在桂林医学院附属医院心内科住院的充血性心力衰竭患者208例[年龄(66.1±13.5)岁]。①使用罗氏2010全自动分析仪测定其脑钠肽前体质量浓度,根据测定值把患者分为0.05]。③相关回归分析示脑钠肽前体质量浓度,左心房及左心室直径与QTc间期呈直线正相关(P<0.05-0.01),QTc间期与QT间期离散度呈直线正相关(P<0.014)。结论:①充血性心力衰竭患者患者血浆脑钠肽前体质量浓度与QTc间期有很好的相关性。②二者联合应用有助于充血性心力衰竭患者危险程度的分层,同时增高示预后不良。

关键词：充血性心力衰竭脑钠肽前体 QTc间期

老年充血性心力衰竭患者血浆脑钠肽前体水平与长期预后的关系

在线全文

学校读者我要写书评

暂无评论

中国组织工程研究与临床康复 2007年第25期11卷 4895-4898页

作者：张建义黄文新阳跃中潘迪华莫新玲夏中华徐彤彤桂林医学院附属医院心内科广西壮族自治区桂林市541001

目的:血浆脑钠肽水平对于充血性心力衰竭的预后评估均具有重要意义,但脑钠肽前体的敏感性和特异性更高。分析血浆脑钠肽前体水平对老年充血性心力衰竭患者长期预后的预测价值。方法:选择2003-05/2005-07在桂林医学院附属医院心内科住院... 详细信息

目的:血浆脑钠肽水平对于充血性心力衰竭的预后评估均具有重要意义,但脑钠肽前体的敏感性和特异性更高。分析血浆脑钠肽前体水平对老年充血性心力衰竭患者长期预后的预测价值。方法:选择2003-05/2005-07在桂林医学院附属医院心内科住院的心力衰竭患者208例及本科同期收住院的急性冠状动脉综合征组患者26例,另外选择正常对照组30例,为本院的医学生,以上观察对象均自愿参加观察。分别测定各组观察对象的血浆脑钠肽前体水平,均在入院的第1天完成,患者出院后不再测定脑钠肽前体。使用惠普500型心动图检测心力衰竭组患者的心脏各腔室直径及射血指数。对所有出院的心力衰竭患者均进行电话随访,每3个月随访1次,平均随访2年,只电话询问死亡还是健在。结果:心力衰竭患者208例、急性冠状动脉综合征患者26例及正常对照组30例全部进入结果分析,无脱落。①各组观察对象的血浆脑钠肽前体水平比较:心力衰竭组是正常对照组的150倍[(4.82±0.75)μg/L,(31.38±29.28)ng/L(P<0.01)],是急性冠脉综合征组的23倍[(208.80±120.13)ng/L(P<0.01)]。②不同年龄、性别、病种、心功能分级心力衰竭患者血浆脑钠肽前体水平比较:心力衰竭患者脑钠肽前体的水平随年龄的增加而升高(P<0.05～0.01);女性显著高于男性(P<0.01);心功能不同级别间脑钠肽前体的水平呈倍数增加(P<0.01),死亡者显著高于生存者(P<0.01)。③心力衰竭患者血浆脑钠肽前体水平与各临床指标的相关性分析:心力衰竭患者血浆脑钠肽前体水平与年龄、左心室直径及纽约心脏协会心功能分级呈正相关(r=0.310,0.283,0.647,P<0.05～0.01),与射血指数呈负相关(r=-0.327,P<0.01)。结论:老年心力衰竭患者的血浆脑钠肽前体水平明显增高,与之相关的预后不良危险因素包括心功能分级增高、射血分数降低、左心室直径扩大、老年及女性心力衰竭患者等。

关键词：心力衰竭充血性冠状动脉疾病利钠肽脑超声心动描记术

Semaphorin 7A impairs barrier function in cultured human corneal epithelial cells in a manner dependent on nuclear factor-kappa B

在线全文

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2024年第3期17卷 444-453页

作者： Cheng-Cheng Yang Xiu-xia Yang xiao-Jing zhao Heng Wang Zi-Han Guo Kai Jin Yang Liu Bin-Hui Li Department of Ophthalmology the Fifth Affiliated HospitalSun Yat-sen UniversityZhuhai 519000Guangdong ProvinceChina Department of Ophthalmology Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical UniversityHangzhou 310006Zhejiang ProvinceChina Eye Institute of xiamen University Fujian Provincial Key Laboratory of Ophthalmology and Visual ScienceSchool of MedicineXiamen UniversityXiamen 361005Fujian ProvinceChina

●AIM:To evaluate the role of semaphorin 7A(Sema7A)and its associated regulatory mechanisms in modulating the barrier function of cultured human corneal epithelial cells(HCEs).●METHODS:Barrier models of HCEs were treated with recombinant human Sema7A at concentrations of 0,125,250,or 500 ng/mL for 24,48,or 72h in *** electrical resistance(TEER)as well as Dextran-fluorescein isothiocyanate(FITC)permeability assays were conducted to assess barrier *** quantify tight junctions(TJs)such as occludin and zonula occludens-1(ZO-1)at the mRNA level,reverse transcriptionpolymerase chain reaction(RT-PCR)analysis was *** was used to examine the activity of the nuclear factor-kappa B(NF-κB)signaling pathway and the production of TJs *** analyses were employed to localize the ***-linked immunosorbent assay(ELISA)and RT-PCR were utilized to observe changes in interleukin(IL)-1β*** investigate the role of NF-κB signaling activation and IL^(-1)βin Sema7A’s anti-barrier mechanism,we employed 0.1μmol/L IκB kinase 2(IKK2)inhibitor IV or 500 ng/mL IL^(-1)receptor(IL-1R)antagonist.●RESULTS:Treatment with Sema7A resulted in decreased TEER and increased permeability of Dextran-FITC in HCEs through down-regulating mRNA and protein levels of TJs in a time-and dose-dependent manner,as well as altering the localization of ***,Sema7A stimulated the activation of inhibitor of kappa B alpha(IκBα)and expression of IL-1β.The anti-barrier function of Sema7A was significantly suppressed by treatment with IKK2 inhibitor IV or IL-1R antagonists.●CONCLUSION:Sema7A disrupts barrier function through its influence on NF-κB-mediated expression of TJ proteins,as well as the expression of IL-1β.These findings suggest that Sema7A could be a potential therapeutic target for the diseases in corneal epithelium.

关键词： human corneal epithelial barrier function transepithelial electrical resistance zonula occludens-1 occludin nuclear factor-kappa B

向量图参数分析心力衰竭患者心肌复极离散指标及预后

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国组织工程研究与临床康复 2007年第48期11卷 9747-9750页

作者：张建义黄文新阳跃中潘迪华莫新玲徐彤彤夏中华刘琼蔡钰石红梅桂林医学院附属医院心内科广西壮族自治区桂林市541001

目的:心电图QT间期离散度对心血管事件的预测价值仍有争议,实验从向量图的角度探讨QT间期离散度的应用及其对心力衰竭患者预后的预测价值。方法:①临床资料:2003-05/2005-07在桂林医学院附属医院住院的充血性心力衰竭患者229例为充血性... 详细信息

目的:心电图QT间期离散度对心血管事件的预测价值仍有争议,实验从向量图的角度探讨QT间期离散度的应用及其对心力衰竭患者预后的预测价值。方法:①临床资料:2003-05/2005-07在桂林医学院附属医院住院的充血性心力衰竭患者229例为充血性心力衰竭组,年龄60～83岁;同期住院的急性冠脉综合征患者26例为急性冠脉综合征组;30例年龄匹配的正常人为正常对照组。所有受试者对实验均知情同意,实验符合伦理学标准。②检测方法:使用北京美高仪软件技术有限公司提供的Q/CPCGY 001-2000型心电综合分析系统检测向量图;同时检测与向量图同步记录的12导联心电图;应用上海群天医疗器械有限公司生产的Q/NYOZ-02-2001型动态心电图仪检测室性心律失常的发生情况;对充血性心力衰竭患者电话随访2年,只询问健在还是死亡。③观察指标:向量图各指标与QT间期离散度的关系、二者与心律失常事件和死亡率的关系。结果:285例受试者的资料均进入结果分析。①向量图指标:充血性心力衰竭组及急性冠脉综合征组额面及横面的QRS/T夹角均大于正常对照组(P<0.05);死亡组额面及横面的QRS/T夹角均显著大于生存组(P<0.05);室性早搏≥LOWNⅢ级者的额面及横面QRS/T夹角的平均角度均显著大于<Ⅲ级者(P<0.05～0.01)。②心电图指标:充血性心力衰竭组及急性冠脉综合征组QTc、间期离散度均大于正常对照组(P<0.05);死亡者的QTc显著大于生存者(P<0.01);室性早搏≥LOWNⅢ级QT者的QTc显著大于<Ⅲ级者(P<0.05)。③相关性分析:额面及横面的QRS/T环的夹角与QT间期离散度呈显著正相关(P<0.05)。结论:向量图的QRS/T夹角、心电图的QTc是反映心肌电不稳定、预测充血性心力衰竭患者心律失常事件、死亡率、以及长期预后不良的有用指标,QT间期离散度无预测作用。

关键词： QT间期离散度向量图心电图心力衰竭

在线全文

学校读者我要写书评

暂无评论

“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,design equations and runaway speed of the Kaplan turbine

在线全文

学校读者我要写书评

暂无评论

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

作者： zh.zhang zhAW 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

Master equation and runaway speed of the Francis turbine

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

作者： zh.zhang 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