光敏丝室探测器PET的触发判选处理器

介绍了为光敏丝室探测器PET而设计的触发判选处理器（TRIG）的结构和原理，该处理器具有触发判选，计数率损失测量，随机符合事例率测量，探测器分区计数统计以及系统定标等多项功能，由于应用了EPLD技术和流水线作业等技术，实现了TRIG系统的高集成度和高性能 。     

考虑初始椭圆度的套管抗载能力分析

针对套管的不同初始椭圆度建立了套管、水泥环、地层平面应变力学模型。分析认为，在非均匀地应力作用下，套管内壁的径向变形较大，抗载能力明显降低，破坏主要是由地下非均匀地应力引起的；随着初始椭圆度的增加，在地应力作用下套管各部位产生的应力分布不均程度增大，使得套管抗外载能力减弱。建议在生产和使用过程中应严格将套管椭圆度控制在规定的范围内，从而提高套管的抗载能力。     

Use of the Extreme Groups Approach: A Critical Reexamination and New Recommendations.

Analysis of continuous variables sometimes proceeds by selecting individuals on the basis of extreme scores of a sample distribution and submitting only those extreme scores to further analysis. This sampling method is known as the extreme groups approach (EGA). EGA is often used to achieve greater statistical power in subsequent hypothesis tests. However, there are several largely unrecognized costs associated with EGA that must be considered. The authors illustrate the effects EGA can have on power, standardized effect size, reliability, model specification, and the interpretability of results. Finally, the authors discuss alternative procedures, as well as possible legitimate uses of EGA. The authors urge researchers, editors, reviewers, and consumers to carefully assess the extent to which EGA is an appropriate tool in their own research and in that of others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

基于TS101型DSP链路口的多通道高精度数据采集电路设计

介绍一种基于数字信号处理器(DSP)TS101链路口的多通道高精度数据采集电路的设计方法,详细阐述利用多个ADS8361型A/D转换器进行数据采集,并经TS101链路口传输数据的FP-GA和DSP设计实现,讨论如何提高A/D转换精度的问题.     

非理想截面脊形介质光波导导波模式的研究

提出了一种求解任意截面形状脊形光波导的方法，先利用有效折射率的概念解出某种截面形状脊形光波导的等效折射率，再利用转移矩阵的理论求解出波导的模式色散方程。     

Comparison of finite element reliability methods

The spectral stochastic finite element method (SSFEM) aims at constructing a probabilistic representation of the response of a mechanical system, whose material properties are random fields. The response quantities, e.g. the nodal displacements, are represented by a polynomial series expansion in terms of standard normal random variables. This expansion is usually post-processed to obtain the second-order statistical moments of the response quantities. However, in the literature, the SSFEM has also been suggested as a method for reliability analysis. No careful examination of this potential has been made yet. In this paper, the SSFEM is considered in conjunction with the first-order reliability method (FORM) and with importance sampling for finite element reliability analysis. This approach is compared with the direct coupling of a FORM reliability code and a finite element code. The two procedures are applied to the reliability analysis of the settlement of a foundation lying on a randomly heterogeneous soil layer. The results are used to make a comprehensive comparison of the two methods in terms of their relative accuracies and efficiencies.     

提高检测数据准确性 促进选钼生产稳定高效

本文从6个方面对选钼2个作业段的取样方式进行了校验,通过对检测数据的比对分析,找出了选钼2个作业段数据存在矛盾的原因,并针对原因采取了有效的措施,保证了检测数据的准确性,促进了选钼生产的稳定高效。     

Identification of Chaos Representations of Elastic Properties of Random Media Using Experimental Vibration Tests

This paper deals with the experimental identification of the probabilistic representation of a random field modelling the Young modulus of a nonhomogeneous isotropic elastic medium by experimental vibration tests. Experimental data are constituted of frequency response functions on a given frequency band and for a set of observed degrees of freedom on the boundary of specimens. The random field representation is based on the polynomial chaos decomposition. The coefficients of the polynomial chaos are identified setting an inverse problem and then in solving an optimization problem related to the maximum likelihood principle.     

Effect-Size Indices for Dichotomized Outcomes in Meta-Analysis.

It is very common to find meta-analyses in which some of the studies compare 2 groups on continuous dependent variables and others compare groups on dichotomized variables. Integrating all of them in a meta-analysis requires an effect-size index in the same metric that can be applied to both types of outcomes. In this article, the performance in terms of bias and sampling variance of 7 different effect-size indices for estimating the population standardized mean difference from a 2 × 2 table is examined by Monte Carlo simulation, assuming normal and nonnormal distributions. The results show good performance for 2 indices, one based on the probit transformation and the other based on the logistic distribution. (PsycINFO Database Record (c) 2010 APA, all rights reserved)