高复生的心理健康和应急事件状况及社会支持在两者间的作用机制

采用症状自评量表（SCL-90）、社会支持评定量表（SSRS）和青少年生活事件量表（ASLEC）对450名高考复习生进行测评,再应用结构方程模型技术对社会支持的中介效应进行检验。分析结果表明,高复生心理健康水平比常模差,并且比应届高三学生有更大的应激强度;社会支持在负性生活事件和心理健康之间起中介作用,占总效应的9．5％。     

基于ANSYS的高速包装机的椭圆齿轮模态分析

采用有限元法,建立了椭圆齿轮的动力学模型,通过有限元分析软件ANSYS对椭圆齿轮进行模态分析,得到了椭圆齿轮的前六阶固有频率和对应振型。该方法和所得结果为动态设计提供了参考,同时也为椭圆齿轮系统的动态响应计算和分析奠定了基础。     

TBZ在MWCNT—DHP膜修饰电极上的电化学分析研究

在pH：2．0的B—R（Britton—Robinson）的缓冲溶液中,对制备的多壁碳纳米管,双十六烷基磷酸（MwcNT—D船）膜修饰电极进行了循环伏安法（CV）表征;分别研究了涕必灵（1BZ）在裸玻碳电极（GcE）和MWCNT—DHP膜修饰电极上的电化学行为,采用微分脉冲伏安法（DTV）,以MWCNT—DHP膜修饰电极为工作电极,建立了一个简单、快速、灵敏的涕必灵电化学分析检测体系;并结合固相萃取技术,测定了环境水中涕必灵含量,检测限达到2．0×10-8mol·L-1,平均回收率为97．28％-99．40％,RSD为1．3％～2．8％（n=6）。     

Estimation of MIMIC Model Parameters with Multilevel Data

The purpose of this simulation study was to assess the performance of latent variable models that take into account the complex sampling mechanism that often underlies data used in educational, psychological, and other social science research. Analyses were conducted using the multiple indicator multiple cause (MIMIC) model, which is a flexible and effective tool for relating observed and latent variables. The data were simulated in a hierarchical framework (e.g., individuals nested in schools) so that a multilevel modeling approach would be appropriate. Analyses were conducted accounting for and not accounting for the nested data to determine the impact of ignoring such multilevel data structures in full structural equation models. Results highlight the differences in modeling results when the analytic strategy is congruent with the data structure and what occurs when this congruency is absent. Type I error rates and power for the standard and multilevel methods were similar for within-cluster variables and for the multilevel model with between-cluster variables. However, Type I error rates were inflated for the standard approach when modeling between-cluster variables.     

关于广义Pexider方程解的注记

许多领域的研究离不开函数方程,特别在动力系统和嵌入流中十分重要,函数方程有各种形式,对他们的求解是复杂的,有时甚至是相当困难的。文章首先研究了两类广义Pexider函数方程,对其中一类我们用换元法将其转化为已有的Pexider对数方程,从而求得其一般解,对另一类我们采用将方程两端先微分使其转化为微分方程,然后求解微分方程,从而获得了它的二次可微解.     

Is academic tracking related to gains in learning competence? Using propensity score matching and differential item change functioning analysis for better understanding of tracking implications

This study analyzes gains in cognitive components of learning competence with respect to cohorts based on ability tracking in a Czech longitudinal study. Propensity score matching is used to form parallelized samples of academic and non-academic track students and to eliminate the effect of selective school intake. We applied regression models on the total scores to test for the overall track effect. Furthermore, we analyze scores and gains on the subscores and check for differential item functioning in Grade 6 and in change to Grade 9. While after 3 years, no significant difference between the two tracks was apparent in the total learning competence score, we did, however, find significant differences in some subscores and in the functioning of some items. We argue that item-level analysis is important for deeper understanding of the tracking implications and may provide the basis for more precise evidence-based decisions regarding the tracking policy.     

Is everyone in class in agreement and why (not)? Using student and teacher reports to predict within-class consensus on goal structures

Students in the same class can differ considerably in their perceptions of teaching quality, but little is known about the drivers of this lack of agreement. In this study, we relied on within-class consensus as a measure of agreement in students' perceptions and explored both student-reported predictors (Sample 1) and teacher-reported predictors (Sample 2) of consensus in students’ ratings of six goal structures dimensions (task, autonomy, recognition, grouping, evaluation, time). Classroom-level results from multi-level models indicated that student-perceived differential teacher treatment negatively predicted consensus regarding evaluation, as well as achievement heterogeneity, whereas instructional clarity positively predicted consensus for recognition, grouping, and evaluation, as well as class-average achievement (Sample 1). Mediating effects of achievement heterogeneity and achievement were not statistically significant. In Sample 2, negative effects of teacher-reported emotional exhaustion and teaching-related anxiety on consensus were observed for several dimensions. Teaching-related enjoyment had no effect.     

Application of colour metallography in the examination of ancient metals

The use of colour in the metallographic examination of ancient metals is useful both for research and teaching purposes. Application of different optical methods of examination include: polarized light, with or without a first-order red compensator, and differential interference contrast microscopy (DIC). The use of DIC can be combined with the other techniques mentioned in the text for the examination of etched or unetched metal surfaces, which are best observed microscopically using a metallograph. Colour techniques are now used routinely in industrial metallography, and are available for a variety of metals and alloys. Colour tint etching can be used to enhance grain structure or different phases present in the metallic artefact which may not be visible in conventional etched samples, or which lack optical contrast. Many more applications of these techniques in the examination of ancient metals will be published in the literature as they become better known and second-hand equipment with DIC lenses enter the market at a price suitable for conservation laboratories to purchase them.     

一种非线性偏微分方程的小波解法

利用微分算子的紧支撑小波表示,讨论了一种非线性偏微分方程的Daubechies小波解,给出了此类问题的求解步骤,并做出了相应的数值结果。