回转式电晕放电架的结构设计

电晕处理机是一种应用非常广泛的塑料薄膜表面处理设备,放电架是其主要组成部分。针对放电架结构的特点,介绍了一种放电架总体结构的设计方法,并对其主要组成部件的结构设计进行了详细的论述。这种放电架采用回转式结构,利用气缸推动回转组件运转,提高了放膜的方便性和安全性。     

基于IPsec的VPN技术应用与研究

利用VPN技术可以在开放的、不安全的公用通信网络上,建立一条安全、稳定的通信隧道,保证数据安全的传输．基于IPsec协议的VPN技术采用了多种技术手段很好的解决了网络通信的安全问题,必将成为VPN发展的主流方向．以IP安全协议体系IPSec作为基础,通过对VPN安全技术的分析,提出了基于IPsec构建VPN的解决方案,简要的分析了嵌套式隧道应用方案．最后对VPN网关系统基本性能进行了测试分析,给出了相关的结果．     

土地利用特征与出行属性对交通方式选择的影响:以南京主城区为例(英文)

以南京市主城区为例,基于随机效用最大化理论,建立了居民的出行方式选择分层logit模型.研究了个人社会经济属性、城市土地利用特征以及出行属性等因素对居民出行方式选择的影响.同时,通过计算出行时间与出行费用的直接弹性和交叉弹性分析它们对出行方式选择的敏感程度.研究结果表明:非机动化的出行方式在居住可达性和就业可达性高的区域更加具有吸引力,小汽车拥有者更加偏向于选择小汽车出行;相对出行费用而言,选择公交与地铁的居民对出行时间更加敏感;完善的公共交通系统以及城市土地利用与交通政策的有效结合有助于缓解由于城市的不断扩张引起的交通拥堵水平.     

Towards a re-conceptualization of teachers' self-efficacy beliefs: tackling enduring problems with the quantitative research and moving on

Various commentators have argued for years that the study of teachers' self-efficacy (TSE) beliefs, largely dominated by quantitative research methodologies, has been confused. Contentious issues include the very conceptualization of these beliefs, how they are defined and accessed through research and how the research is used. One of the biggest anomalies is that, despite claiming that these beliefs are task-specific, many quantitative researchers have both assessed them globally and portrayed them as hard to impact. In contrast, some qualitative researchers have emphasized the task-specific nature of these beliefs and their potential for transformation through self-doubt, reflection and learning. This literature review examines these and other contentious issues, focusing on studies published in international peer-reviewed journals in the last few years, looking, through the use of search terms and the surveying of abstracts followed by detailed reading, for evidence of developing understandings and changing research practices. This review highlights continuing misalignment between theory and method in much of the literature, but also identifies promising research directions. Mixed methods and qualitative research designs seem to have the potential to produce insightful findings that can make the study of TSE beliefs of greater use to teacher educators than has previously been the case.     

A More Powerful Test in Three-Level Cluster Randomized Designs

Abstract

Field experiments that involve nested structures frequently assign treatment conditions to entire groups (such as schools). A key aspect of the design of such experiments includes knowledge of the clustering effects that are often expressed via intraclass correlation. This study provides methods for constructing a more powerful test for the treatment effect in three-level cluster randomized designs with two levels of nesting (at the second and third levels). When the intraclass correlation structure at the second and third level is assumed to be known, the proposed test provides higher estimates of power than those obtained from the typical test based on level-3 unit means, because it preserves the degrees of freedom associated with the number of level-2 and level-1 units. The advantage in power estimates is more pronounced when the number of level-3 units (e.g., schools) is small and the samples are homogeneous (e.g., low-achieving schools).     

Power Analysis in Two-Level Unbalanced Designs

Previous work on statistical power has discussed mainly single-level designs or 2-level balanced designs with random effects. Although balanced experiments are common, in practice balance cannot always be achieved. Work on class size is one example of unbalanced designs. This study provides methods for power analysis in 2-level unbalanced designs with random effects. Overall, the nesting affects power negatively, the treatment affects power positively, and the Level-2 units affect power more than Level-1 units. Computing power assuming balanced designs provides reasonable estimates only when imbalance is mild or moderate. When imbalance is large or extreme, computing power assuming balanced designs produces larger estimates of power. The use of the harmonic mean provides accurate estimates of power in unbalanced 2-level designs even when imbalance is large.     

Investigating the causes of reading comprehension failure: The comprehension-age match design

The reading-level (or reading-age) match design has become a widely-used tool for investigating the possible direction of the relation between particular skills and word reading ability: Cause or consequence. This paper outlines an analogous method for identifying candidate causes of reading comprehension failure, the `comprehension-age match design' and discusses the strengths and limitations of this design.     

How does the modern football goalkeeper train? – An exploration of expert goalkeeper coaches’ skill training approaches

ABSTRACT

The football goalkeeper position arguably represents a unique role within the team sport. Despite its highly complex skill demands, research on football goalkeeping has only sporadically examined the position within isolated and limited parameters. In particular, there is limited literature on “modern” skill acquisition training methods and approaches within the field of goalkeeper training. In a cross-cultural study with fifteen expert goalkeeper coaches, researchers here examined the overarching research question of “how does the modern football goalkeeper train?”. Semi-structured interviews explored expert coaches’ views on critical skills for performance in goalkeeping and the training approaches used to develop these critical skills. Results indicate that four skill sets are considered essential by goalkeeper coaches, these are: decision-making skills, athleticism, mentality, and technical skills. In terms of developing these skills in goalkeeper-specific training, the majority of expert coaches apply a similar microstructure to training sessions. This structure involves a steady progression from simple to complex training tasks, where for large parts, isolated technical training appears to be prioritised over a holistic training approach that integrates technical skills and perceptual-cognitive components (e.g., decision making). Scientific and practical recommendations for researchers and practitioners in the field of football goalkeeper coaching are provided.     

在n阶仿射平面中构造多种类型的BIB设计

在n阶仿射平面中,利用点作处理,线与线之间的位置关系作区组,构造出多种类型的BIB设计。     

楚铜器纹饰的审美特征及其文化内涵

该文着重探讨楚青铜器纹饰发生发展的演变规律、装饰特征 ,阐明其相应的文化背景 ,指出楚铜器纹饰在审美上求奇、求美、花样翻新的价值取向 ,乃是楚民族传统审美心理积淀的结果 ,同时又与当时社会意识形态的变化有关。在楚人独创精神的培育下 ,楚铜器龙纹逐渐演化成为具有楚域风格的装饰纹样。