检索结果-南通市图书馆

Damping controller design based on FO-PID-EMA in VSC HVDC system to improve stability of hybrid power system

Journal of Central South University 2020年第2期27卷 403-417页

作者： Nima SHAFAGHATIAN arvin kiani Naser TAHERI Zahra RAHIMKHANI Seyyed Saeed MASOUMI Department of Electrical Engineering Zanjan BranchIslamic Azad UniversityZanjanIran Department of Mechanical Engineering Tabriz BranchIslamic Azad UniversityTabrizIran Department of Electrical Engineering Faculty of QuchanKhorasan Razavi BranchTechnical and Vocational University(TVU)Khorasan RazaviIran Department of Computer Engineering Sarvestan BranchIslamic Azad UniversitySarvestanIran Department of Electrical Engineering Yasuj BranchIslamic Azad UniversityYasujIran

Wind energy sources have different structures and functions from conventional power plants in the power *** resources can affect the exchange of active and reactive power of the ***,power system stability will be affected by the performance of wind power plants,especially in the event of a *** this paper,the improvement of the dynamic stability in power system equipped by wind farm is examined through the supplementary controller design in the high voltage direct current(HVDC)based on voltage source converter(VSC)transmission *** this regard,impacts of the VSC HVDC system and wind farm on the improvement of system stability are ***,an algorithm based on controllability(observability)concept is proposed to select most appropriate and effective coupling between inputs-outputs(IO)signals of system in different work *** selected coupling is used to apply damping controller ***,a fractional order PID controller(FO-PID)based on exchange market algorithm(EMA)is designed as damping *** analysis of the results shows that the wind farm does not directly contribute to the improvement of the dynamic stability of power ***,it can increase the controllability of the oscillatory mode and improve the performance of the supplementary controller.

关键词： hybrid power system high voltage direct current based on voltage source converter(VSC HVDC) fractional order PID(FO-PID)damping controller exchange market algorithm

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

Stress analysis of thermally affected rotating nanoshafts with varying material properties

引用

Acta Mechanica Sinica 2016年第5期32卷 813-827页

作者： Keivan kiani Department of Civil Engineering K.N. Toosi University of Technology

Based on the surface elasticity theory of GurtinMurdoch, thermo-elastic fields within rotating nanoshafts with varying material properties subjected to a thermal field are explicitly examined. Accounting for the surface energy effect, the nonclassical boundary conditions are enforced in the cases of fixed-free and free-free conditions. The effects of variation of material properties, temperature of the environment, angular velocity, and radius of the outer radius on the radial displacement, hoop and radial stresses are investigated. In all performed studies, the role of the surface effect on the thermo-elastic field of the nanostructure is methodically discussed.

关键词： Rotating nanoshaft Thermo-elastic field Surface energy effect Non-classical boundary conditions Analytical modeling

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

On the limitations of linear beams for the problems of moving mass-beam interaction using a meshfree method

引用

Acta Mechanica Sinica 2012年第1期28卷 164-179页

作者： Keivan kiani Ali Nikkhoo Department of Civil Engineering Islamic Azad University Department of Civil Engineering University of Science and Culture

This paper deals with the capabilities of linear and nonlinear beam theories in predicting the dynamic response of an elastically supported thin beam traversed by a moving mass. To this end, the discrete equations of motion are developed based on Lagrange＇s equations via reproducing kernel particle method （RKPM）. For a particular case of a simply supported beam, Galerkin method is also employed to verify the results obtained by RKPM, and a reasonably good agreement is achieved. Variations of the maximum dynamic deflection and bending moment associated with the linear and nonlinear beam theories are investigated in terms of moving mass weight and velocity for various beam boundary conditions. It is demonstrated that for majority of the moving mass velocities, the differences between the results of linear and nonlinear analyses become remarkable as the moving mass weight increases, particularly for high levels of moving mass velocity. Except for the cantilever beam, the nonlinear beam theory predicts higher possibility of moving mass separation from the base beam compared to the linear one. Furthermore, the accuracy levels of the linear beam theory are determined for thin beams under large deflections and small rotations as a function of moving mass weight and velocity in various boundary conditions.

关键词： Nonlinear beam theory Moving mass-beam in- teraction Euler-Bernoulli beam theory - Reproducing kernel particle method (RKPM) Galerkin method (GM)

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

Modified consecutive modal pushover procedure for seismic investigation of one-way asymmetric-plan tall buildings

引用

Earthquake Engineering and Engineering Vibration 2012年第2期11卷 221-232页

作者： Faramarz Khoshnoudian Mahdi kiani Department of Civil Engineering Amirkabir University of TechnologyTehranIran

The effects of higher modes and torsion have a significant impact on the seismic responses of asymmetric-plan tall buildings. A consecutive modal pushover (CMP) procedure is one of the pushover methods that have been developed to consider these effects. The aim of this paper is to modify the (CMP) analysis procedure to estimate the seismic demands of one-way asymmetric-plan tall buildings with dual systems. An analysis of 10-, 15- and 20-story asymmetric-plan buildings is carried out, and the results from the modified consecutive modal pushover (MCMP) procedure are compared with those obtained from the modal pushover analysis (MPA) procedure and the nonlinear time history analysis (NLTHA). The MCMP estimates of the seismic demands of one-way asymmetric-plan buildings demonstrate a reasonable accuracy, compared to the results obtained from the NLTHA. Furthermore, the accuracy of the MCMP procedure in the prediction of plastic hinge rotations is better than the MPA procedure. The new pushover procedure is also more accurate than the FEMA load distribution and the MPA procedure.

关键词： modified consecutive modal pushover seismic demands nonlinear time history analysis asymmetric-plan tall buildings torsion

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

Evaluation of soil erodibility factor(k)for loess derived landforms of Kechik watershed in Golestan Province,North of Iran

引用

Journal of Mountain Science 2016年第11期13卷 2028-2035页

作者： Farshad kiani Aboutaleb GHEZELSEFLO Dept.of Soil Science Gorgan university of agricultural sciences and natural resourcesGorgan ***Iran Natural resources organization of Golestan province Gorgan ***Iran

The technique proposed by Wischmeier ＆ Smith for estimating the soil erodibility factor is among the most important methods in this regard. Given the high amounts of silt and lime content in loess soils of eastern parts of Golestan province in Iran, this study aims to evaluate the ability of Wischmeier ＆ Smith index to estimate the soil erodibility of this region. Soil erodibility was first obtained by Wischmeier nomograph and then was compared with the actual values obtained by selecting six plots and then performing physical and chemical tests on these samples. Using the nomograph, Wischmeier index was calculated to be about 0.05-0.092 Mg h MJ？1 mm？1. The results showed that Wischmeier index was 182, 4.11, 6 and 0.35 times than actual value in field with half-hour rainfall, Fournier index, SWAT value with half-hour rainfall and SWAT value with Fournier index, respectively. Obtained results showed that erodibility estimated by Wischmeier ＆ Smith index was higher than the actual measured value. Poor performance of this index in loess soils indicates the need for further research in this field.

关键词： Soil erodibility Loess Wischmeier nomograph Iran

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

Graphitization in CK 45 Steel

引用

Journal of Materials Science & Technology 2009年第2期25卷 164-168页

作者： A.R. kiani-Rashid Department of Materials Engineering Faculty of Engineering Ferdowsi University of Mashhad Mashhad Iran

The purpose of this study was to determine the influence of heat treatment cycle on graphite phase formation on CK 45 steel. The presence of well distributed graphite in the matrix is responsible for the good mechanical and thermal properties of this kind of alloy. Such properties include excellent wear resistance, higher resistance to thermal shock, and higher resistance to oxidation at high temperature. A number of specimens were made up of appropriate design to provide the experimental materials. The transformation phase to a free carbon microstructure during graphitization under different conditions was then examined for the most successful experimental steels. Austenitising temperature of 920℃ and the following isothermal heat treatment of 750℃ at different holding times were used. Microstructures were examined by OM （optical microscopy） and SEM （scanning electron microscopy）. Furthermore, it was found that isothermal transformation at 750℃ for different soaking times produced a typical microstructure. Also, the amount of graphite increased with increasing isothermal heat treatment time. Heat treatment leading to supersaturation of iron with carbon was described and some of the consequences of the supersaturation were presented. Finally, the formation of the thermodynamically stable state of the graphite taken from the supersaturated solid solution was discussed.

关键词： Graphitization Carbon Microstructure Heat treatment Phase transformation

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

Zn(NO_3)_2·6H_2O/2,4,6-trichloro-1,3,5-triazine(TCT) a mild and selective system for nitration of phenols

引用

Chinese Chemical Letters 2010年第4期21卷 403-406页

作者： Firouzeh Nemati Hossein kiani Department of Chemistry Faculty of ScienceSemnan UniversitySemnanIran

Certain phenols and naphthols were nitrated regioselectively with Zn(NO)·6HO/TCT in acetonitrile as solvent at room temperature and short reaction time in good *** reaction condition was *** is a cheap and commercial... 详细信息

关键词： Nitration Phenols 2 4 6-Trichloro-l 3 5-triazine Regioselective

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

Assessing dynamic response of multispan viscoelastic thin beams under a moving mass via generalized moving least square method

引用

Acta Mechanica Sinica 2010年第5期26卷 721-733页

作者： Keivan kiani Ali Nikkhoo Bahman Mehri Department of Civil Engineering Sharif University of Technology Department of Mathematical Sciences Sharif University of Technology

Dynamic response of multispan viscoelastic thin beams subjected to a moving mass is studied by an efficient numerical method in some detail. To this end, the unknown parameters of the problem are discretized in spatial domain using generalized moving least square method （GMLSM） and then, discrete equations of motion based on Lagrange＇s equation are obtained. Maximum deflection and bending moments are considered as the important design parameters. The design parameter spectra in terms of mass weight and velocity of the moving mass are presented for multispan viscoelastic beams as well as various values of relaxation rate and beam span number. A reasonable good agreement is achieved between the results of the proposed solution and those obtained by other researchers. The results indicate that, although the load inertia effects in beams with higher span number would be intensified for higher levels of moving mass velocity, the maximum values of design parameters would increase either. Moreover, the possibility of mass separation is shown to be more critical as the span number of the beam increases. This fact also violates the linear relation between the mass weight of the moving load and the associated design parameters, especially for high moving mass velocities. However, as the relaxation rate of the beam material increases, the load inertia effects as well as the possibility of moving mass separation reduces.

关键词： Moving mass-beam interaction - Multispan viscoelastic beam Euler-Bernoulli beam Generalized moving least square method (GMLSM)

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

Mechanical responses of pristine and defective hexagonal boron-nitride nanosheets:A molecular dynamics investigation

引用

Frontiers of Structural and Civil Engineering 2020年第3期14卷 623-631页

作者： Mohammad SALAVATI arvin MOJAHEDIN Ali Hossein Nezhad SHIRAZI Institute of Structural Mechanics Bauhaus-Universitat WeimarWeimar D-99423Germany

ABSTRACT In this work we conducted classical molecular dynamics(MD)simulation to investigate the mechanical characteristics and failure mechanism of hexagonal boron-nitride(h-BN)*** and defective structure of h-BN nanosheets were considered under the uniaxial tensile loadings at various *** defective structure contains three types of the most common initial defects in engineering materials that are known as cracks,notches(with various length/size),and point vacancy defects(with a wide range of concentration).MD simulation results demonstrate a high load-bearing capacity of extremely defective(amorphized)h-BN *** results also reveal that the tensile strength decline by increasing the defect content and temperature as *** MD results provide a comprehensive and useful vision concerning the mechanical properties ofh-BN nanosheets with/without defects,which is very critical for the designing of nanodevices exploiting the exceptional physics of h-BN.

关键词： hexagonal boron-nitride mechanical properties crack notch point defects molecular dynamics

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

A Green and Highly Efficient Protocol for Catalyst-free Kno- evenagel Condensation and Michael Addition of Aromatic Al- dehydes with 1,3-Cyclic Diketones in PEG-400

引用

Chinese Journal of Chemistry 2011年第11期29卷 2407-2410页

作者： Firouzeh, Nemati Hossein, kiani Department of Chemistry Faculty of Science Semnan University Semnan Iran

A convenient, highly efficient and green approach for synthesis of tetraketones from aromatic aldehydes with dimedone and 1,3-indanedione at room temperature in PEG-400 is described. The use of PEG-400 as the reaction medium and avoiding the use of any catalyst makes the process environmentally benign. Seven new compounds are reported.

关键词： Michael addition green chemistry polyethelene glycol Knoevenagel condensation dimedone,1,3-Indanedione

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

在线全文

在线全文

在线全文

在线全文

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

在线全文

在线全文

在线全文

在线全文

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：