检索结果-南通市图书馆

Applied Mathematics and Mechanics(English Edition) 2007年第1期28卷 69-78页

作者： K.hooman h.gurgenci School of Engineering the University of Queensland Brisbane Australia

Effect of temperature-dependent viscosity on fully developed forced convection in a duct of rectangular cross-section occupied by a fluid-saturated porous medium is investigated analytically. The Darcy flow model is applied and the viscosity-temperature relation is assumed to be an inverse-linear one. The case of uniform heat flux on the walls, i.e. the h boundary condition in the terminology of Kays and Crawford [12], is treated. For the case of a fluid whose viscosity decreases with temperature, it is found that the effect of the variation is to increase the Nusselt number for heated walls. having found the velocity and the temperature distribution, the second law of thermodynamics is invoked to find the local and average entropy generation rate. Expressions for the entropy generation rate, the Bejan number, the heat transfer irreversibility, and the fluid flow irreversibility are presented in terms of the Brinkman number, the Péclet number, the viscosity variation number, the dimensionless wall heat flux, and the aspect ratio （width to height ratio）. These expressions let a parametric study of the problem based on which it is observed that the entropy generated due to flow in a duct of square cross-section is more than those of rectangular counterparts while increasing the aspect ratio decreases the entropy generation rate similar to what previously reported for the clear flow case by Ratts and Rant [14].

关键词： entropy generation rate forced convection porous medium rectangular duct temperature-dependent viscosity

两相流体脉动流动时的传热以及受热壁面状况对传热的影响

在线全文

学校读者我要写书评

暂无评论

西安交通大学学报 1983年第3期 42-49页

作者：林宗虎 ,T.N.Veziroglu,S.Kakac,h.gurgenci,A.Mentes 西安交通大学美国Miami大学清洁能源研究所西安交通大学土耳其中东技术大学西安交通大学美国Miami大学西安交通大学美国Miami大学所长国际氢能学会主席西安交通大学名誊教授教授美国Miami大学客座教授博士助理研究员博士助理研究员

本文发表了氟里昂-11在六种不同内壁面状况的垂直管中蒸发且脉动流动时的沸腾传热试验数据,以及用高速摄影观察研究的结果.研究结果归纳成计算式,Nu=190Cs（P/Pc）0.25(（qDe）/(▽hvμe)0.7e-0.125x可用以预测这一流动工况下两相流动... 详细信息

本文发表了氟里昂-11在六种不同内壁面状况的垂直管中蒸发且脉动流动时的沸腾传热试验数据,以及用高速摄影观察研究的结果.研究结果归纳成计算式,Nu=190Cs（P/Pc）0.25(（qDe）/(▽hvμe)0.7e-0.125x可用以预测这一流动工况下两相流动的传热系数.

关键词：脉动流动沸腾传热光滑管时间平均传热系数壁面两相流体

Neuroinflammation as a therapeutic target in huntington's disease

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第3期20卷 817-818页

作者： Andrea Kwakowsky Thulani h.Palpagama Center for Brain Research and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CentreUniversity of GalwayGalwayIreland

In 1872, George huntington presented his essay “On Chorea” to the Meigs and Mason Academy of Medicine and, in doing so, detailed a disease that would later bear his name. huntington's disease(hD) is a genetic, neurodegenerative disease that manifests as the loss of motor control,cognitive impairment,and mood and psychiatric changes in paents.

关键词： huntington inflammation Medicine

Glial response in the midcingulate cortex in huntington’s disease

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第1期20卷 207-208页

作者： Thulani h.Palpagama Andrea Kwakowsky Center for Brain Research and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CenterUniversity of GalwayGalwayIreland

huntington’s disease(hD)is a genetic disease characterized by the progressive degeneration of the striatum and *** can present with a variety of symptoms that can broadly be classified into motor symptoms,inclusive of choreatic movements and rigidity,mood and psychiatric symptoms,such as depression and apathy,and cognitive symptoms,such as cognitive *** causal mutation underlying hD results from an expansion of a CAG repeat sequence on the IT15 gene,resulting in the formation and accumulation of a mutant huntingtin protein.

关键词： huntington degeneration cortex

Comparative chemical sensor for detection of chromium(Ⅵ) in aqueous solution

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2025年第1期21卷 21-27页

作者： Sura h.AL-REKABI A.A.ALWAhIB Electrical Technique Department Al Suwayrah Technical Institute Middle Technical University Laser and Optoelectronics Department University of Technology-Iraq

A process for purifying aqueous solutions containing heavy and toxic metals such as chromium（Cr） has been investigated. One of the extremely harmful pollutants in rivers and seawater is the heavy metal ions due to their direct impacts on human, animals and plants are hexavalent Cr（Ⅵ）. Consequently, highly sensitive sensor to detect Cr is essential. Surface plasmon resonance（SPR） technique has attracted huge research interest in detecting heavy metals specifically. In this study, three types of prism-based SPR sensor, gold（Au）/silver（Ag）, Au/polyaniline（PANI） and Au/titanium dioxide（TiO2） nanostructured films, are investigated as potential sensing material to detect the presence of Cr（Ⅵ） ions in water. The base Au layer with thickness of 48.3 nm is deposited on a glass slide for all sensors. For Au/Ag, Au/PANI nanofibers and Au/TiO2sensor films, the Cr（Ⅵ） concentration is varied from 1 ppm to 15 ppm with sensitivity of 0.270 °ppm-1, 0.082 °ppm-1and 0.039 °ppm-1, respectively. Based on these results, the Au/PANI nanofibers are the most sensitive to Cr（Ⅵ） among the tested sensing materials.

关键词： Titanium dioxide

Does mesenchymal stem cell’s secretome affect spinal sensory circuits?Implication for pain therapies

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第1期20卷 181-183页

作者： Francesco Ferrini Esri h.Juárez Adalberto Merighi Department of Veterinary Sciences University of TurinGrugliascoTOItaly Department of Psychiatry and Neuroscience UniversitéLavalQuébec CityQCCanada

Mesenchymal stem cells(MSCs)are multipotent adult stem cells of mesodermal origin that can be isolated from various tissues,including bone marrow,tooth pulp,adipose tissue,and umbilical *** have gained significant attention in regenerative medicine due to their ability to modulate the immune system and favor tissue *** enrich the medium in which they are cultivated with a broad range of bioactive molecules,including growth factors,cytokines,chemokines,enzymes,nucleic acids,and extracellular vesicles that collectively compose the MSC *** increasing number of pre-clinical studies suggest that delivering in vivo an MSC-conditioned medium(i.e.,the medium collected from MSC cultures after at least 3 days of exposure)exerts neuroprotective and anti-inflammatory effects in a variety of neurological conditions.

关键词： protective clinical collective

Dynamic stress concentration in an infinitely long cylindrical cavity due to a point spherical source embedded within a fluid-saturated poroelastic formation of infinite extent

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 139-156页

作者： h.hOSSEINI O.BALILAShAKI Department of Mechanical Engineering Faculty of EngineeringGolestan University

The effects of a harmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely within a fluid-saturated poroelastic formation of infinite extent are examined theoretically. It is assumed that the source is located outside the cavity at a specified distance from the borehole axis. The magnitudes of the hoop and radial stresses beside the pore pressures exerted on the interface and inside the porous medium surrounding the borehole are calculated and discussed. Biot's poroelastic modeling along with three types of boundary conditions for the cylindrical interface including the ideal fluid, empty borehole, and rigid inclusion with a hard boundary is employed for the analysis. Utilizing a proper translational addition theorem for expressing the incident spherical wave in terms of cylindrical wave expansions, the proposed boundary conditions at the interface are satisfied. Stresses are formulated by means of wave potential functions in a three-dimensional(3D) manner. The effects of the frequency and the radial distance between the source and borehole on the induced stresses are examined for the first cylindrical modes over frequency spectra. Two permeability conditions for the interface and three types of soils for the porous formation are considered throughout the analysis. To give an overall outline of the study, a numerical example is presented. The results clearly indicate that the distance is a key parameter and has considerable effects on the induced stress values. In addition, the interface permeability condition and soil characteristics play an important role in determining the dynamic response of the borehole. Finally,the obtained results are compared with the relevant analyses existing in the literature for some limit cases, and good agreement is achieved.

关键词： Stress concentration

基于切削电流指数新异检测的长壁采煤机监测方法研究

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

湖南科技大学学报（自然科学版） 2006年第2期21卷 55-58页

作者：秦国军胡茑庆官志强 hal gurgenci 国防科技大学机电工程与自动化学院湖南长沙410073 澳大利亚昆士兰大学采矿联合研究中心

在定义采煤机切削电流指数的基础上,采用统计分析和支持向量机方法,对采煤机健康状态进行了新异故障检测方法的研究,通过大量正常数据,构建和训练了新异类检测器.通过对澳大利亚某煤矿1号采煤机的实测数据应用表明,该检测器可有效检测... 详细信息

在定义采煤机切削电流指数的基础上,采用统计分析和支持向量机方法,对采煤机健康状态进行了新异故障检测方法的研究,通过大量正常数据,构建和训练了新异类检测器.通过对澳大利亚某煤矿1号采煤机的实测数据应用表明,该检测器可有效检测意外发生的未知故障.图7,表3,参8.

关键词：长壁采煤机切削电流指数新异类检测统计分析支持向量机

Free vibration and transient response of double curved beams connected by intermediate straight beams

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-TALOOKOLAEI h.GhANDVAR E.JUMAEV S.KhATIR T.CUONG-LE School of Mechanical Engineering Babol Noshirvani University of Technology Department of Mechanical Engineering Faculty of Engineering New Uzbekistan University University of Business and Science Center for Engineering Application and Technology Solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. Subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANSYS, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

关键词： Kinetic energy

植物系统发生海报——以演化视角介绍植物多样性的科教资料项目

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

生物多样性 2025年

作者：蒋陈焜郁文彬饶广远黎怀成 Julien B.Bachelier hartmut h.hilger Theodor C.h.Cole 北京大学生命科学学院蛋白质与植物基因研究国家重点实验室北京大学前沿交叉学科研究院北京大学-清华大学生命科学联合中心中国科学院西双版纳热带植物园综合保护中心/云南省热带雨林与亚洲象保护重点实验室 Dahlem Centre of Plant Sciences (DCPS)， Institute of Biology， Structural and Functional Plant Diversity， Freie Universit?t Berlin

中国的植物多样性保护行动虽然提升了公众对多样性的认识，但这些努力往往未能深入到理解植物多样性演化及其保护的深层意义。从演化的视角进行植物多样性宣传教育，有利于促进对多样性的综合理解，增进对多样性保护的认可。然而， ... 详细信息

中国的植物多样性保护行动虽然提升了公众对多样性的认识，但这些努力往往未能深入到理解植物多样性演化及其保护的深层意义。从演化的视角进行植物多样性宣传教育，有利于促进对多样性的综合理解，增进对多样性保护的认可。然而，现有资料多集中于物种的识别、鉴定与分类，缺乏从生物演化角度对植物多样性进行系统性介绍的内容。本文介绍了一个具有全球影响力的科教资料案例——由美裔德国植物学家Theodor C. h. Cole发起的植物系统发生海报(Plant Phylogeny Posters)项目。该项目通过整合最新的系统与演化植物学研究成果，以系统发生为线索介绍植物多样性及其亲缘关系，旨在利用系统发生树所蕴含的丰富演化思想内涵，启发读者理解植物多样性与演化。海报以系统发生树结合植物类群的形态、地理分布、物种数量等数据信息，直观展示了多个分类等级的重要类群的演化历史。在数十所大学和科研机构的45位研究人员的努力下， 70张系统发生海报已被翻译成中文，并向所有人免费开放获取。这一科教项目有望为增进公众深入理解植物多样性及其保护行动提供宝贵的资源和帮助。

关键词：植物多样性演化系统发生科教资料