土层地基上建筑结构混合控制的减震效率

研究土 -结构相互作用对结构混合控制减震效能的影响。首先建立了土层地基上结构混合控制的运动方程 ,通过不同输入地震波、不同土层剪切波速、不同结构参数等条件下的数值分析 ,讨论了桩基础对结构混合控制减震效率的影响规律。数值结果表明 :对于土 -结构相互作用体系 ,采用混合控制的减震效率明显要强于单一的 TL D的减震效率 ;在土层较为坚硬的情况下 ,混合控制仍具有较高减震效能 ;随着土层变软 ,土 -结构相互作用减小结构地震反应的效应趋于明显 ,混合控制的减震效率明显降低 ,因此 ,对软土地基上的结构实施混合控制时 ,必须先要正确分析土 -结构体系的地震反应。     

Iterative ultrasonic signal and image deconvolution for estimation of the complex medium response

The ill‐conditioned inverse problem of estimating ultrasonic medium responses by deconvolution of RF signals is investigated. The primary difference between the proposed method and others is that the medium response function is assumed to be complex‐valued rather than restricted to being real‐valued. Derived from the complex medium model, complex Wiener filtering is presented, and a Hilbert transform related limitation to inverse filtering type methods is discussed. We introduce a nonparametric iterative algorithm, the least squares method with point count regularization (LSPC). The algorithm is successfully applied to simulated and experimental data and demonstrates the capability of recovering both the real and imaginary parts of the medium response. The simulation results indicate that the LSPC method can outperform Wiener filters and improve the resolution of the ultrasound system by factors as high as 3.7. Experimental results using a single element transducer and a conventional medical ultrasound system with a linear array transducer show that despite the errors in pulse estimation and the noise in the RF signals, excellent results can be obtained, demonstrating the stability and robustness of the algorithm. © 2006 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 266–277, 2005     

新型无机闪烁体CeF3的时间特性研究

CeF3是新型快响应无机闪烁体．对近年国内研制的CeF3无机闪烁体的时间特性进行了研究，包括脉冲辐射诊断所关心的CeF3对快脉冲γ辐射源的时间响应．如上升时间、半高竟、脉冲后沿；同时推算并使用了用脉冲法获得晶体发光衰减常数的简单估算公式，获得的CeF3衰减常数值与国外研究同行其它测量方法得到的结果基本一致。     

基于随机有限元的梁单元反应变异性分析

针对工程中由于不确定因素的影响而导致的结构反应的变异,利用随机有限元推导了在多个随机变量作用下梁单元结构反应变异的公式,以镗刀杆工作的位移变异为例,详细地介绍了其计算过程,并将其与解析法和Monte-Carlo法进行了对比,分析了各自的适用范围,为不确定性结构的可靠性分析奠定了基础。     

基于小波变换的超声电机启动和关断特性的测试与分析

叙述了本研究中心研发的超声电机瞬态测试系统及其测试方法。由于噪声的影响，启动、关断响应曲线常常不太光滑，以往采用平滑技术和数字滤波等处理办法，获得启动和关断响应特性精度较差。本文利用小波变换对原始启动、关断响应数据进行分析，去除噪声，从而较准确地获得了超声电机启动和关断的响应时间。实验结果表明，超声电机确实具有毫秒级的响应时间。     

Computer Solutions in Choosing Automatic Process Regulators

The paper discusses the use of the URA software for choosing automatic regulators and calculating their setting parameters, as it is intended for simulating transient response by computer.     

The measuring method of early lateral energy fraction in the scale model experiments

This paper introduces a measuring method of early lateral energy fraction in the scale model experiments. According to the interference principle of half wave length making the high frequency figure-8 directional microphone. With the signal-processing technique, a receiving and analyzing system, for the measurements of lateral energy fraction in the scale model is realized.     

Structured Latent Curve Models for the Study of Change in Multivariate Repeated Measures.

This article considers a structured latent curve model for multiple repeated measures. In a structured latent curve model, a smooth nonlinear function characterizes the mean response. A first-order Taylor polynomial taken with regard to the mean function defines elements of a restricted factor matrix that may include parameters that enter nonlinearly. Similar to factor scores, random coefficients are combined with the factor matrix to produce individual latent curves that need not follow the same form as the mean curve. Here the associations between change characteristics in multiple repeated measures are studied. A factor analysis model for covariates is included as a means of relating latent covariates to the factors characterizing change in different repeated measures. An example is provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phase I IASC-ASCE Structural Health Monitoring Benchmark Problem Using Simulated Data

Structural health monitoring (SHM) is a promising field with widespread application in civil engineering. Structural health monitoring has the potential to make structures safer by observing both long-term structural changes and immediate postdisaster damage. However, the many SHM studies in the literature apply different monitoring methods to different structures, making side-by-side comparison of the methods difficult. This paper details the first phase in a benchmark SHM problem organized under the auspices of the IASC–ASCE Structural Health Monitoring Task Group. The scale-model structure adopted for use in this benchmark problem is described. Then, two analytical models based on the structure—one a 12 degree of freedom (DOF) shear-building model, the other a 120-DOF model, both finite element based—are given. The damage patterns to be identified are listed as well as the types and number of sensors, magnitude of sensor noise, and so forth. MATLAB computer codes to generate the response data for the various cases are explained. The codes, as well as details of the ongoing Task Group activities, are available on the Task Group web site at 〈http://wusceel.cive.wustl.edu/asce.shm/〉.     

考虑风电接入和气电转换的综合能源系统日前区间优化

针对气电综合能源系统优化调度中未充分挖掘可调度因素、未充分考虑风电预测误差不确定性的现状,研究含风电的气电综合能源系统日前区间优化调度方法。首先,基于区间数学对风电出力的不确定性进行区间描述,综合考虑抽水蓄能、气电双向转换以及需求响应等资源和技术,并用区间数学表示优化目标和优化约束,构建含高比例风电的气电综合能源系统日前优化模型,综合优化系统的经济性、环保性。然后,基于区间序关系和可能度的方法将区间优化模型转化为确定性优化模型,继而采用Jaya算法进行求解,保证求解的高效性和解空间的可行性。最后,进行算例分析,仿真结果验证了综合利用抽水蓄能、气电双向转换以及需求响应等要素对系统进行区间优化,能取得优化效果上的优势,并能为系统调度人员提供风电不确定度对系统优化影响的信息。