基于有限元计算的螺栓接头预紧力和允许外力设计方法

用MSC.Marc软件建立螺栓接头的三维接触有限元模型,计算得到了螺栓接头中螺纹段最大等效应力随预紧力的变化曲线、残余预紧力和螺纹段最大等效应力随被连接件所受轴向外力的非线性变化曲线,提出了基于这些曲线设计高强度螺栓接头预紧力和允许外力的方法。     

土钉墙技术在坡、残积土边坡支护中的应用

结合工程实例，阐述了坡、残积土层中边坡土钉墙支护的设计与施工要点，并针对施工过程中出现的特殊情况，提出相应的解决方案与处理措施。     

Ti-50．9at％Ni薄膜组织和相转变的研究

采用磁控溅射方法在Si片沉积了Ti-50．9at％Ni形状记忆合金薄膜,并将薄膜分别在不同温度下进行退火．利用示差扫描量热方法（DSC）、X射线衍射仪（XRD）、透射电镜（TEM）研究了薄膜退火前后形貌、相变特征及应力随退火温度的变化．实验结果表明：溅射态薄膜为非晶态,其晶化温度范围为430℃-535℃,晶化同时伴随着Ti3Ni4相的析出;退火后的薄膜随着退火温度的升高,Rs、Af、Ms均呈上升趋势．薄膜的残余应力随着退火温度的增加而逐渐减少．     

Using students’ feedback for teacher education: measurement invariance across pre-service teacher-rated and student-rated aspects of quality of teaching

Comparing self-perceived quality of teaching to students’ perception can be used in higher education to improve the quality of teaching of pre-service teachers in teacher education. However, comparing these measurements from different perspectives is only meaningful if the same constructs are being measured. To shed light on this comparison’s meaningfulness, we scrutinised whether aspects of quality of teaching are measured in the same way across pre-service teachers and their students by means of measurement invariance analyses. To do so, 272 pre-service teachers in teacher education rated aspects of their quality of teaching, and were rated by their 4851 students. Measurement invariance across these perspectives was tested in multilevel structural equation models. Strong measurement invariance held for two aspects of quality of teaching; for the third, one item lacked weak measurement invariance. Pre-service teachers perceived their quality of teaching lower than their students. In conclusion, aspects of quality of teaching can be compared across perspectives, and teacher education should encourage pre-service teachers to use students’ feedback as a valuable resource for improving their quality of teaching.     

发电厂厂用电源切换方式的探讨

分析厂用电切换时施加在电动机群上的电压,即母线残压的变化过程;指出为提高快速切换成功率,应根据实际情况确定允许的合闸相角差;提出新型切换装置应具备快速切换、同期捕捉切换、残压切换功能。     

Application of time-temperature superposition method in thermal aging life prediction of shipboard cables

The life of shipboard cables will decrease due to the complex aging processes. In terms of the safety perspective, remaining life prediction of the cable is essential to maintain a reliable operation. In this paper, firstly, based on Arrhenius equation, residual life of new styrene-butadiene cable is calculated; result indicates that the degradation rate which changes with time is proportional to thermal temperature. Then second order dynamic model is adopted into the residual life prediction, combined with the time-temperature superposition method （TTSP）, and a new residual life model is proposed. According to the accelerated thermal aging experiment data and Arrhenius equation, TTSP method demonstrates to be an efficient way for life prediction, and life at normal temperature can be estimated by this model. In order to monitor the state of styrene-butadiene cable more accurately, an improved residual life model based on equivalent environment temperature of cable is proposed, and life of cable under real operation is analyzed. Result indicates that this model is credible and reliable, and it provides an important theoretical base for residual life of cables.     

A short German Physical-Self-Concept Questionnaire for elementary school children (PSCQ-C): Factorial validity and measurement invariance across gender

Research on children’s physical self-concept (PSC) is increasingly recognised as an important field of psychology. However, there is a lack of instruments suitable for younger children at elementary school age. In the present study, a short German 21-item Physical Self-Concept-Questionnaire for children (PSCQ-C) was tested measuring seven specific facets of elementary school children’s PSC (strength, endurance, speed, flexibility, coordination, physical appearance, global sport competence). A number of 770 elementary school children aged 8–12 years completed the PSCQ-C. Results showed good psychometric properties and high reliabilities of the seven scales. Confirmatory factor analysis revealed that the presumed 7-factor model fitted the data best compared to a global 1- and 2-factor model. Also, full measurement invariance was strongly established. Correlations among the seven scales were mainly moderate. Gender differences were suggestive of developmental trends that are consistent with prior studies. These results provide support that the PSCQ-C is a confidential instrument with sound psychometric properties measuring seven specific facets of elementary school children’s PSC.     

调质40Cr钢喷丸和喷丸后精车残余应力的实验研究

对不同硬度的调质40Cr钢喷丸后的残余应力和不同硬度的调质40Cr钢喷丸后精密车削的残余应力,进行了测试与分析。研究结果对控制和利用机械加工的残余应力,具有理论和实际意义     

建水紫陶装饰工艺的艺术特点

作为中国"四大名陶"之一的建水紫陶诞生于云南西南边陲的建水县,迄今已有近千年的历史积淀,它以自身独特而鲜明的两大工艺技术,即"彩泥刻填"和"无釉磨光"在中国制陶工艺的历程中占据着自己的一席之地。此外,素有"文人陶"之称的建水紫陶除特殊的工艺技巧外,诸多工匠艺人在陶面上进行书画创作,以陶代纸,独特的装饰艺术塑造出建水紫陶区别于一般陶器的艺术特点。     

浅析固定资产折旧

首先简单地介绍固定资产的有关概念 ,计提折旧的方法以及两种方法的异同等 ;其次介绍固定资产折旧方法的特点、固定资产折旧方法的优点和缺点、固定资产折旧方法在目前的社会地位 ,以及固定资产折旧方法的利弊 ,针对固定资产折旧方法的存在问题所带来的各种措施。