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Earthquake Engineering and Engineering Vibration 2019年第1期18卷 219-231页

作者： Zhang Yunfeng Liu Heng dept.of Civil & Environmental Engineering University of Maryland College Park

Large amplitude vibration of mast arm structures due to wind loads are the primary contributing factor to the reduced fatigue life of signal support structures. To alleviate this problem of wind-induced in-plane vibration of mast arm signal structures, a particle-thrust damping based turned mass damper(PTD-TMD) device is adopted and its damping effect is characterized experimentally. The particle-thrust damping is a passive damping device that does not require electric power and is temperature independent. Based on the calibration test, an equivalent dynamic model of the PTD-TMD device is developed and used for numerical simulation study. The damping effects of this PTD-TMD device on signal support structures was investigated through both numerical analysis and laboratory testing of a 50-ft(15.24 m) mast arm structure including both free vibration and forced vibration tests. The experimental test and numerical study results show that vibration response behavior of mast arm signal support structures can be significantly reduced by installing the PTD-TMD that can increase the critical damping ratio of the mast arm signal structures to 4%. The stress range at the welded connection between the mast arm and traffic pole is also reduced.

关键词： fatigue mast arm signal support structures tuned mass damper vibration

Grey series time-delay predicting model in state estimation for power distribution networks

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Journal of Harbin Institute of Technology(New Series) 2003年第2期10卷 120-123页

作者：蔡兴国安天瑜周苏荃 dept.of Electrical Engineering

A new combined model is proposed to obtain predictive data value applied in state estimation for radial power distribution networks. The time delay part of the model is calculated by a recursive least squares algorithm of system identification, which can gradually forget past information. The grey series part of the model uses an equal dimension new information model (EDNIM) and it applies 3 points smoothing method to preprocess the original data and modify remnant difference by GM(1,1). Through the optimization of the coefficient of the model, we are able to minimize the error variance of predictive data. A case study shows that the proposed method achieved high calculation precision and speed and it can be used to obtain the predictive value in real time state estimation of power distribution networks.

关键词：电力系统配电系统电力网状态估计灰色预报模型时滞

Physics-based electrical modelling of CIGS thin-film photovoltaic modules for system-level energy yield simulations

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npj Flexible Electronics 2022年第1期6卷 854-862页

作者： Santhosh Ramesh Arttu Tuomiranta Ali Hajjiah Marc Meuris Bart Vermang Jef Poortmans Imec imo-imomecThor Park 83203600 GenkBelgium EnergyVille imo-imomecThor Park 83203600 GenkBelgium KU Leuven Dept.of Electrical Engineering(ESAT)LeuvenBelgium Hasselt University imo-imomecMartelarenlaan 423500 HasseltBelgium Kuwait University Dept.of Electrical EngineeringCollege of Engineering and PetroleumKuwaitKuwait

Copper indium gallium selenide(CIGS)is a commercialized,high-efficiency thin-film photovoltaic(PV)*** state-of-theart energy yield models for this technology have a significant normalized root mean square error(nRMSE)on power estimation:De Soto model—26.7%;PVsyst model—12%.In this work,we propose a physics-based electrical model for CIGS technology which can be used for system-level energy yield simulations by people across the PV value *** model was developed by considering models of significant electrical current pathways from literature and adapting it for the system-level *** improved it further by incorporating temperature and irradiance dependence of parameters through characterisation at various operating *** also devised a module level,non-destructive characterization strategy based on readily available measurement equipment to obtain the model *** model was validated using the measurements from multiple commercial modules and has a significantly lower power estimation nRMSE of 1.2%.

关键词： CIGS electrical PVsyst

INERTIA EFFECTS OF THE FLUID AND CYLINDER IN COAXIAL CYLINDRICAL RHEOMETER

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维普期刊数据库

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Acta Mechanica Sinica 1998年第3期14卷 234-238页

作者：张建保匡震邦 dept.of Physics The Forth Military Medical UniversityXi'an 710032China dept.of Eng.Mechanics Shanghai Jiaotong UniversityShanghai 200240China

The inertias of the fluid and the inner cylinder in coaxial cylinder rheometer (CACR) have great influence on the unsteady flow of non-Newtonian fluid. Even for the Newtonian fluid there exist the so called stress overshoot phenomenon. This phenomenon was studied and a method correcting the measured results for an unsteady flow in the rheometer was proposed. It is found that the inertia effect of the fluid can be ignored when the gap between cylinders is small. (Edited author abstract) 11 Refs.

关键词： inertia rheometer fluid hemorheology

On Memory Capacity of the Probabilistic Logic Neuron Network

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Journal of Computer Science & Technology 1993年第3期8卷 252-256页

作者：张钹张铃 dept.of Computer Science and Technology Tsinghua UniversityBeijing 100084 dept.of Mathematics Anqing Teachers' CollegeAnqingAnhui 246011

In this paper,the memory capacity of Probabilistic Logic Neuron(PLN)network is discussed. We obtain two main results:(1)the method for constructing a PLN network with a given memory capacity;(2)the relationship between the memory capacity and the size of a PLN *** show that the memory capacity of a PLN network depends on not only the number of input ports of its element but also the number of elements *** results provide a new method for designing a PLN network.

关键词： PLN network memory capacity

THE NONLINEAR INTERACTION OF VORTEX RINGS WITH A FREE SURFACE

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Acta Mechanica Sinica 1997年第2期13卷 120-129页

作者：叶取源 C.K.Chu dept.of Engineering Mechanics Shanghai Jiao Tong UniversityShanghai 200030China dept.of Applied Physics Columbia UniversityNew YorkNY 10027USA

Nonlinear interactions of vortex rings with a free surface are considered in an incompressible, ideal fluid using the vortex contour dynamics technique and the boundary integral equation method. The flow is axisymmetric and the vorticity is linearly distributed in the vortex. Effects of the gravity and the surface tension as well as the initial geometric parameter of the vortex on the interaction process are investigated in considerable detail. The interaction process may be divided into three major stages: the vortex free-traveling stage, the collision stage, and the vortex stretching and rebounding stage. Time evolutions of both the vortex and free surface under various conditions are provided and analyzed. Two kinds of waves exist on the free surface during interaction. In a special case where the gravity and surface tension are very weak or the vortex is very strong, an electric-bulb-like 'cavity' is formed an the free surface and the vortex is trapped in the 'cavity' for quite a. long time, resulting in a large amount, of fluid above the mean fluid surface.

关键词： vortex ring vortex dynamics contour dynamics nonlinear free surface

STUDY OF THERMAL DEFORMATION OF MICROELECTRONICS PACKAGING PRODUCT BY INTERFEROMETRIC TECHNIQUE

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Acta Mechanica Sinica 1997年第2期13卷 186-192页

作者：卿新林王国韬戴福隆 dept.of Engineering Mechanics Tsinghua UniversityBeijing 100084China

In this paper, the out-of-plane deformation of silicon surface of Direct Chip Attachment (DCA) assembly, under thermal loading, was measured in real-time by Twyman/Green interferometry. The contour maps of the out-of-plane displacement fields of silicon surface under thermal loading and cycling of various temperature were obtained, Experimental results show that the relation between the out-of-plane displacement and temperature is nonlinear and varies with temperature cycling, due to nonlinear mechanical behavior of the materials used in electronic packaging. A comparison of the aut-of-plane displacement Gelds of silicon surface measured by T/G interferometry in real-time and replicating technique of high temperature specimen grating of moire interferometry was made.

关键词： electronic packaging thermal deformation Twyman/Green interferometry Moire interferometry

A new method for PQ disturbance detection and identification

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Journal of Harbin Institute of Technology(New Series) 2007年第3期14卷 392-397页

作者：吕干云程浩忠丁屹峰翟海保 dept.of Information Science and Engineering Zhejiang Normal University dept.of Electrical Engineering Shanghai Jiaotong UniversityShanghai 200030China dept.of Electrical Engineering Shanghai Jiaotong University

A new method based on phase-shift and N-1 Support Vector Machines(SVMs)is presented for power quality(PQ)disturbance detection and *** phase-shift and simple algebra operation,the method detects out the PQ disturbances easily and *** a data dealing process is carried out to extract features from the detecting *** SVM theory is introduced into the identification of PQ disturbances.N kinds of PQ disturbances are classified with an N-1 SVMs *** testing results show that the proposed method can detect and classify the PQ disturbances ***,the classifier has a good performance on training speed and correct ratio.

关键词：相变支持向量机检测识别 PQ扰动功率

A COMPUTATIONAL METHOD FOR FIRST-EXCURSION RELIABILITY

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Acta Mechanica Sinica 1996年第4期12卷 377-386页

作者：刘宁 dept.of Hydraulic Engineering Tsinghua UniversityBeijing 100084China

An efficient computational method is suggested for the first-excursion reliability assessment of nonstationary process. In the proposed method, the nonlinear performance function is Linearized at the Hasofer-Lind point obtained by an iterative algorithm. The problem of the nonstationary processes is solved by the discrete-time method, in which the precision can be controlled by choosing the steps of discretization. The derived formulae can be conveniently degraded to calculate both the first-excursion reliability with linear performance function of stationary processes and the time-independent reliability. The suggested method is useful for the analysis of components and systems with nonstationary responses in structural design where some uncertainties are represented by a vector of nonstationary processes. Examples are given to demonstrate the fast convergency and effectiveness of the presented method.

关键词： structural reliability nonstationary processes nonlinear performance function first-excursion reliability

Modeling and cyclic behavior of segmental bridge column connected with shape memory alloy bars

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Earthquake Engineering and Engineering Vibration 2012年第3期11卷 375-389页

作者： Hwasung Roh Andrei M.Reinhorn Jong Seh Lee dept.of Civil and Environmental Engineering Hanyang University dept.of Civil Structural and Environmental EngineeringUniversity at Buffalo The State University of New York

This paper examines the quasi-static cyclic behavior, lateral strength and equivalent damping capacities of a system of post-tensioned segmental bridge columns tied with large diameter martensitic Shape Memory Alloy （SMA） link-bars. Moment-curvature constitutive relationships are formulated and analysis tools are developed for the PT column, including a modified four-spring model prepared for the SMA bars. The suggested system is exemplified using a column with an aspect ratio of 7.5 and twelve 36.5 mm diameter NiTi martensitic SMA bars. A post-tensioning force of 40% to 60% of the tendon yield strength is applied in order to obtain a self re-centering system, considering the residual stress of the martensitie SMA bars. The cyclic response results show that the lateral strength remains consistently around 10% of the total vertical load and the equivalent viscous damping ratios reach 10%-12% of critical. When large diameter NiTi superelastic SMA bars are incorporated into the column system, the cyclic response varies substantially. The creep behavior of the superelastic SMA bar is accounted for since it affects the re-centering capability of the column. Two examples are presented to emphasize the modeling sensitivities for these special bars and quantify their cyclic behavior effects within the column assembly.

关键词： segmental rocking columns shape memory alloy bars cyclic response energy dissipation damping recentering