检索结果-南通市图书馆

Prediction of Vibration Characteristics in Beam Structure Using Sub-Scale Modeling with Experimental Validation

Chinese Journal of Mechanical Engineering 2015年第5期28卷 928-934页

作者： zai behzad ahmed SAMI Saad KHAN M Amir AHMAD Furqan PARK Myung Kyun Structure Design and Development Directorate Institute of Space Technology Department of Civil and Environmental Engineering KAIST Department of Mechanical Engineering Myongji University

Geometric or sub-scale modeling techniques are used for the evaluation of large and complex dynamic structures to ensure accurate reproduction of load path and thus leading to true dynamic characteristics of such structures. The sub-scale modeling technique is very effective in the prediction of vibration characteristics of original large structure when the experimental testing is not feasible due to the absence of a large testing facility. Previous researches were more focused on free and harmonic vibration case with little or no consideration for readily encountered random vibration. A sub-scale modeling technique is proposed for estimating the vibration characteristics of any large scale structure such as Launch vehicles, Mega structures, etc., under various vibration load cases by utilizing precise scaled-down model of that dynamic structure. In order to establish an analytical correlation between the original structure and its scaled models, different scale models of isotropic cantilever beam are selected and analyzed under various vibration conditions（ i.e. free, harmonic and random） using finite element package ANSYS. The developed correlations are also validated through experimental testing The prediction made from the vibratory response of the scaled-down beam through the established sets of correlation are found similar to the response measured from the testing of original beam structure. The established correlations are equally applicable in the prediction of dynamic characteristics of any complex structure through its scaled-down models. This paper presents modified sub-scale modeling technique that enables accurate prediction of vibration characteristics of large and complex structure under not only sinusoidal but also for random vibrations.

关键词： sub-scale modeling resonance frequency vibration characteristics scale factors power spectral density

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Field evaluation of durum wheat landraces for prevailing abiotic and biotic stresses in highland rainfed regions of Iran

引用

The Crop Journal 2015年第5期3卷 423-433页

作者： Reza Mohammadi behzad Sadeghzadeh Hasan Ahmadi Nowzar Bahrami ahmed Amri Dryland Agricultural Research Institute (DARI) Center of Agricultural Research and Natural Resources International Center for Agricultural Research in the Dry Areas (ICARDA)

Biotic and abiotic stresses are major limiting factors for high crop productivity worldwide. A landrace collection consisting of 380 durum wheat(Triticum turgidum L. var. durum) entries originating in several countries along with four check varieties were evaluated for biotic stresses:yellow rust(Puccinia striiformis Westendorf f. sp. tritici) and wheat stem sawfly(WSS) Cephus cinctus Norton(Hymenoptera: Cephidae), and abiotic stresses: cold and drought. The main objectives were to(i) quantify phenotypic diversity and identify variation in the durum wheat landraces for the different stresses and(ii) characterize the agronomic profiles of landraces in reaction to the stresses. Significant changes in reactions of landraces to stresses were *** resistant to each stress were identified and agronomically *** reduction due to the stresses varied from 11.4%(yellow rust) to 21.6%(cold stress) for 1000-kernel weight(TKW) and from 19.9(yellow rust) to 91.9%(cold stress) for grain yield. Landraces from Asia and Europe showed enhanced genetic potential for both grain yield and cold tolerance under highland rainfed conditions of Iran. The findings showed that TKW and yield productivity could be used to assess the response of durum wheat landraces to different stresses. In conclusion, landraces showed high levels of resistance to both biotic and abiotic stresses, and selected landraces can serve in durum wheat breeding for adaptation to cold and drought-prone environments.

关键词： Durum wheat Landraces Biotic and abiotic stresses

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nanoscale control of grain boundary potential barrier, dopant density and filled trap state density for higher efficiency perovskite solar cells

引用

InfoMat 2020年第2期2卷 409-423页

作者： behzad Bahrami Sally Mabrouk Nirmal Adhikari Hytham Elbohy Ashim Gurung Khan M.Reza Rajesh Pathak Ashraful H.Chowdhury Gopalan Saianand Wenjin Yue Jiantao zai Xuefeng Qian Mao Liang Qiquan Qiao Department of Electrical Engineering and Computer Science Center for Advanced Photovoltaics and Sustainable EnergySouth Dakota State UniversityBrookingsSouth Dakota Physics Department Damietta UniversityNew Damietta CityEgypt Global Innovative Center for Advanced Nanomaterials Faculty of EngineeringThe University of NewcastleCallaghanNew South WalesAustralia College of Biochemical Engineering Anhui Polytechnic UniversityWuhuChina Shanghai Electrochemical Energy Devices Research Center School of Chemistry and Chemical EngineeringState Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghaiChina Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion Department of Applied ChemistryTianjin University of TechnologyTianjinChina

In this work,grain boundary(GB)potential barrier(ΔφGB),dopant density(Pnet),and filled trap state density(PGB,trap)were manipulated at the nanoscale by exposing the fabricated perovskite films to various relative humidity(RH)*** mapping of surface potential in the perovskite film revealed higher positive potential at GBs than inside the *** averageΔφGB,Pnet,and PGB,trap in the perovskite films decreased from 0%RH to 25%RH exposure,but increased when the RH increased to 35%RH and 45%*** clearly indicated that perovskite solar cells fabricated at 25%RH led to the lowest average GB potential,smallest dopant density,and least filled trap states *** is consistent with the highest photovoltaic efficiency of 18.16%at 25%RH among the different relative humidities from 0%to 45%RH.

关键词： dopant density filled trap state density grain boundary potential barrier perovskite solar cells relative humidity

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：