检索结果-南通市图书馆

Rotation effect on near-wall turbulence statistics and flow structures

Science China(Physics,Mechanics & Astronomy) 2005年第2期48卷 211-227页

作者： LIU Nansheng lu Xiyun zhuang Lixian Department of Mechanics and Mechanical Engineering University of Science and Technology of China Hefei 230026 China Department of Mechanics and Mechanical Engineering University of Science and Technology of China Hefei 230026 China Department of Mechanics and Mechanical Engineering University of Science and Technology of China Hefei 230026 China

Large eddy simulation (LES) of turbulent flow through an axially rotating pipe, coupled with nonlinear dynamic subgrid-scale (SGS) model, is carried out to investigate rotation effect on the near-wall turbulence characteristics and flow structures. In the rotating turbulent pipe flow, it is found that the tendency towards a relaminarized flow appears and the axial velocity fluctuation is suppressed; however, the azimuthal fluctuation is enhanced due to the presence of the pipe wall rotation. The joint probability density function (joint PDF) of the velocity fluctuations and the probability density function (PDF) of the helicity fluctuation are analyzed in detail. It is revealed that the resolved Reynolds stress and helicity fluctuation in the wall region are closely related to the correlation between the velocity and vorticity fluctuations and affected significantly by the rotation-induced azimuthal mean flow. Further, the budgets of resolved Reynolds stresses indicate that the rotation effect is responsible for the more active turbulent energy redistribution and the production of the azimuthal turbulence fluctuation. The near-wall inclined streaky structures with respect to the axial direction are ascribed to the spiral motion of the fluid induced by the rotating pipe. The turbulence characteristics revealed in this study are of great help for the understanding of physical fundamentals in the rotating turbulent flows and for the development of reliable turbulence model.

关键词： large eddy simulation (LES), dynamic subgrid-scale (SGS) model, rotating turbulent flow, coherent structures.

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

OPTIMAL PRICING STRATEGY TO REDUCE FUEL CONSUMPTION IN ELECTRICITY GENERATION WITH SMART METER

引用

Journal of Systems Science and Systems Engineering 2015年第1期24卷 81-106页

作者： Xiaoyan Xu zhuang Ma Liang Xu Ye lu School of Management University of Science & Technology of China School of Management Zhejiang University Department of Management Science City University of Hong Kong

It has been widely recognized that the efficiency of a thermal power system can be improved by technological advancement of electricity generation and manipulation of electricity consumption. The smart meter enables two-way communication between the customers and the electricity generation system. The electricity generation system uses price incentive （i.e. a higher price in the peak period and a lower price in the off-peak period） to shift part of demands from peak to off-peak period under the smart grid environment. Given the fact that fuel consumption in each period is a strictly increasing convex function of power output, we propose two-period and multi-period pricing strategies, and study the effect of different pricing strategies on reducing fuel consumption.

关键词： Pricing strategy smart meter energy consumption,convex programming

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

Promoting the methanol oxidation catalytic activity by introducing surface nickel on platinum nanoparticles

引用

Nano Research 2018年第4期11卷 2058-2068页

作者： Siqi lu Huiming Li Jingyao Sun Zhongbin zhuang State Key Lab of Organic-Inorganic Composites Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing Key Lab of Energy Environmental Catalysis Beijing University of Chemical Technology Beijing 100029 China

High performance methanol oxidation reaction （MOR） catalysts are critical to the performance of attractive, direct methanol fuel cells. Here, we use surface controlled PtNi alloy nanoparticles as model catalysts to study the MOR mechanism and give further guidance to the design of new high performance MOR catalysts. The enhanced MOR activity of PtNi alloy was mainly attributed to the enhanced OH adsorption owing to surface Ni sites. This suggests that the MOR undergoes the Langmuir-Hinshelwood mechanism, whereby adsorbed CO is removed with the assistance of adsorbed OH. Within the PtNi catalyst, Pt provides methanol adsorption sites （in which methanol is converted to adsorbed CO） and Ni provides OH adsorption sites. The optimized Pt-Ni ratio for MOR was found to be 1：1. This suggests that bifunctional catalysts with both CO and OH adsorption sites can lead to highly active MOR catalysts.

关键词： methanol oxidation reaction (MOR) Pt alloy catalysts surface structure OH adsorption

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 miniature triaxial apparatus for investigating the micromechanics of granular soils with in situ X-ray micro-tomography scanning

引用

Frontiers of Structural and Civil Engineering 2020年第2期14卷 357-373页

作者： zhuang cheng Jianfeng WANG Matthew Richard COOP Guanlin YE Department of Architecture and Civil Engineering City University of Hong KongHong Kong 999077China Shenzhen Research Institute of City University of Hong Kong Shenzhen 518057China Department of Civil Environmental and Geomatic EngineeringUniversity College LondonLondon WC1E 6BTUK Department of Civil Engineering Shanghai Jiaotong UniversityShanghai 200240China

The development of a miniature triaxial apparatus is *** conjunction with an X-ray microtomography(termed as X-ray fiCT hereafter)facility and advanced image processing techniques,this apparatus can be used for in situ investigation of the micro-scale mechanical behavior of granular soils under *** apparatus allows for triaxial testing of a miniature dry sample with a size of 8 mm x 16 mm(diameter x height).In situ triaxial testing of a 0.4-0.8 mm Leighton Buzzard sand(LBS)under a constant confining pressure of 500 kPa is *** evolutions of local porosities(i.e.,the porosities of regions associated with individual particles),particle kinematics(i.e.,particle translation and particle rotation)of the sample during the shear are quantitatively studied using image processing and analysis ***,a novel method is presented to quantify the volumetric strain distribution of the sample based on the results of local porosities and particle *** is found that the sample,with nearly homogenous initial local porosities,starts to exhibit obvious inhomogeneity of local porosities and localization of particle kinematics and volumetric strain around the peak of deviatoric *** the post-peak shear stage,large local porosities and volumetric dilation mainly occur in a localized *** developed triaxial apparatus,in its combined use of X-ray|iCT imaging techniques,is a powerful tool to investigate the micro-scale mechanical behavior of granular soils.

关键词： triaxial apparatus X-ray fiCT in situ test micro-scale mechanical behavior granular soils

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

Entanglement wedge cross-section with Gauss-Bonnet corrections and thermal quench

引用

Science China(Physics,Mechanics & Astronomy) 2021年第12期64卷 90-103页

作者： Yong-zhuang Li cheng-Yong Zhang Xiao-Mei Kuang School of Science Jiangsu University of Science and TechnologyZhenjiang 212003China Department of Physics and Siyuan Laboratory Jinan UniversityGuangzhou 510632China Center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China

The entanglement wedge cross section(EWCS) is numerically investigated statically and dynamically in a five-dimension Ad SVaidya spacetime with Gauss-Bonnet(GB) corrections, focusing on two identical rectangular strips on the boundary. In the static case, EWCS increases as the GB coupling constant α increases and disentangles at small separation between two strips for smaller α. For the dynamic case, such a monotonic relationship between EWCS and α holds but the two strips no longer disentangle monotonically as in the static case. In the early thermal quenching stage, the disentanglement occurs at smaller αwith larger separations. Two strips then disentangle at larger separation with larger α as time evolves. Our results indicate that the higher-order derivative corrections, like the entanglement measure in the dual boundary theory, also have nontrivial effects on the EWCS evolution.

关键词： Ad S/CFT correspondence holographic entanglement entropy Gauss-Bonnet gravity entanglement wedge cross section

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

Effect of Controlled Cooling After Hot Rolling on Mechanical Properties of Hot Rolled TRIP Steel

引用

Journal of Iron and Steel Research International 2008年第2期15卷 65-70页

作者： WU Di LI zhuang lu Hui-sheng State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China Department of Material Engineering Shenyang Institute of Aeronautical Engineering Shenyang 110034 Liaoning China Department of Science and Technology Information China Iron and Steel Research Institute Group Beijing 100081 China

A three-step cooling pattern on the runout table（ROT）was conducted for the hot rolled TRIP *** evolution during thermomechanical controlled processing（TMCP）was *** condition of controlled cooling on a ROT in the laboratory rolling mill was *** results indicated that the microstructure containing polygonal ferrite,granular bainite and a significant amount of the stable retained austenite can be obtained through three-step cooling on the ROT after hot *** led to ferrite grain *** cooling after hot rolling resulted in the stability of the remaining austenite and a satisfactory TRIP *** mechanical properties were obtained through TMCP for the hot rolled TRIP steel.

关键词： hot rolled TRIP steel three-step cooling TRIP effect mechanical property

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

Complete f-moment Convergence for Widely Orthant Dependent Random Variables and Its Application in Nonparametric Models

引用

Acta Mathematica Sinica,English Series 2019年第12期35卷 1917-1936页

作者： Chao lu zhuang CHEN Xue Jun WANG School of Mathematical Sciences Anhui University

In this paper,we study the complete f-moment convergence for widely orthant dependent(WOD,for short)random variables.A general result on complete f-moment convergence for arrays of rowwise WOD random variables is *** applications,we present some new results on complete f-moment convergence for WOD random *** also give an application to nonparametric regression models based onWOD errors by using the complete convergence that we ***,the choice of the fixed design points and the weight functions for the nearest neighbor estimator are proposed,and a numerical simulation is provided to verify the validity of the theoretical result.

关键词： Widely orthant dependent random variables complete f-moment convergence complete convergence complete consistency

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

Effect of Thermomechanical Processing on Mechanical Properties of Hot Rolled Multiphase Steel

引用

Journal of Iron and Steel Research International 2008年第1期15卷 55-60页

作者： LI zhuang WU Di lu Hui-sheng Department of Material Engineering Shenyang Institute of Aeronautical Engineering Shenyang 110034 Liaoning China State Key Lab of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China Department of Science and Technology Information China Iron and Steel Research Institute Group Beijing 100081 China

The effect of thermomechanical processing（TMP）on the mechanical properties of hot rolled multiphase steel was *** was conducted using a laboratory hot rolling mill,in which three different kinds of finish rolling deformation degrees and temperatures were *** results indicate that polygonal ferrite,granular bainite,and a considerable amount of stabilized retained austenite can be obtained by *** stability of the retained austenite increases with decreasing finish rolling temperature and increasing finish rolling deformation *** tensile strength（σb）,total elongation（δ）,and the product of ultimate tensile strength by total elongation（σb·δ）for 50% reduction at finish rolling temperature of 700 ℃ reach maximum values [791 MPa,36% and 28 476（MPa·%）,respectively].

关键词： hot rolled multiphase steel finish rolling deformation degree finish rolling temperature retained austenite mechanical property

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

Valuing Credit Default Swap under a double exponential jump diffusion model

引用

Applied Mathematics(A Journal of Chinese Universities) 2014年第1期29卷 36-43页

作者： YANG Rui-cheng PANG Maooxiu JIN zhuang Finance School Inner Mongolia University of Finance and Economics Hohhot 010070 China. School of Mathematics and Information Ludong University Yantai 264000 China.

This paper discusses the valuation of the Credit Default Swap based on a jump market, in which the asset price of a firm follows a double exponential jump diffusion process, the value of the debt is driven by a geometric Brownian motion, and the default barrier follows a continuous stochastic process. Using the Gaver-Stehfest algorithm and the non-arbitrage asset pricing theory, we give the default probability of the first passage time, and more, derive the price of the Credit Default Swap.

关键词： Credit Default Swap Brownian motion double exponential jump diffusion model

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

Low-complexity method for DOA estimation based on ESPRIT

引用

Journal of Systems Engineering and Electronics 2010年第5期21卷 729-733页

作者： Xuebin zhuang Xiaowei Cui Mingquan lu Zhenming Feng Department of Electronic Engineering Tsinghua University Beijing 100084 R R. China

A low-complexity method for direction of arrival（DOA） estimation based on estimation signal parameters via rotational invariance technique（ESPRIT） is *** of using the cross-correlation vectors in multistage Wiener filter（MSWF）,the orthogonal residual vectors obtained in conjugate gradient（CG） method span the signal subspace used by *** computational complexity of the proposed method is significantly reduced,since the signal subspace estimation mainly needs two matrixvector complex multiplications at the iteration of data ***,the prior training data are not needed in the proposed *** overcome performance degradation at low signal to noise ratio（SNR）,the expanded signal subspace spanned by more basis vectors is used and simultaneously renders ESPRIT yield redundant DOAs,which can be excluded by performing ESPRIT once more using the unexpanded signal *** with the traditional ESPRIT methods by MSWF and eigenvalue decomposition（EVD）,numerical results demonstrate the satisfactory performance of the proposed method.

关键词： direction of arrival(DOA) multistage Wiener filter(MSWF) conjugate gradient(CG) estimation signal parameters via rotational invariance technique(ESPRIT) eigenvalue decomposition(EVD).

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

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：