基于抗裂的沥青路面合理结构研究

利用专门的道路设计程序,对半刚性基层沥青路面进行结构力学计算。通过沥青路面内的应力大小和分布分析,得到层底拉应力随结构力学参数(各材料层厚度、模量及结构形式)变化规律,据此提出避免沥青面层疲劳开裂和半刚性基层反射裂缝的沥青路面合理结构,并指出基于抗裂的沥青路面材料组合设计方向。研究结果对半刚性基层沥青路面结构组合设计具有理论参考价值。     

基于SMW工法的城市深基坑开挖稳定性分析

SMW工法具有防渗性好、构造简单、施工速度快、工程造价低等优点,广泛应用于大型隧道工程、城市地下空间开发、高层建筑深基坑开挖支护工程等。以某城市深基坑工程的SMW工法围护结构为研究对象,在考虑水泥土与型钢的相互作用下,建立有限元数值模型,分析开挖过程中墙体位移和土体变形特点。结果表明:开挖深度对墙体侧向位移有显著影响;随着坡面荷载的增加,基坑内外水平方向和竖直方向沉降量均有所增大。     

基于GST的甘肃省产业结构与用水系统分析

以甘肃省2000—2010年统计数据为依据,采用相关分析法和灰色系统理论(GST),对全省及地级行政区的产业结构与产业用水系统进行了定量分析和比较。结果表明:①第一产业构成的下降对产业用水影响很小,第二产业、第三产业构成每增长1%,产业用水将分别减少0.801%和0.730%;②第一产业、第二产业构成与其用水比例关系较为显著,第一产业构成比例每降低1%,其相应的用水比例仅下降0.127%,第二产业构成比例每增长1%,其相应的用水比例将下降0.468%;③第一产业产值与产业用水的综合关联度相对最高,第二产业次之,第三产业相对最小;④大力发展第二产业,积极推动第三产业的发展,限制或适当压缩第一产业的发展规模,是甘肃产业结构调整的方向。     

基于无线传感器网络的水环境监测系统设计

在深入研究ZigBee无线传感器网络的基础上,提出了一种基于无线传感器网络的水环境监测系统的设计方案。该方案借助ZigBee技术在短距离无线通信方面的优势,采用树型拓扑结构组建无线传感器网络,对水环境监测中的水温、pH值、电导率、溶解氧和浊度等重要指标进行远程实时监测。     

淹没丁坝端坡对附近水流结构的调整作用

工程应用中的丁坝往往具有一定的端坡,而且经常处于淹没状态。为了研究端坡对淹没状态下丁坝附近水流结构的调整作用,采用水槽试验和三维浅水模型相结合的方法,分析淹没时丁坝阻水面积相等条件下坝头直立和具有一定端坡时丁坝附近的表层平面流场、底层平面流速分布和底层切应力分布情况。结果表明:淹没程度?H/H?0.17时,丁坝下游仍出现回流区,端坡系数m等于1时相对回流长度和坝头附近流向偏角最大;存在一定端坡时,坝头附近临近底床平面强流速范围和底床切应力范围显著减小或消失,m等于7时能够将丁坝附近流场调整得较为均匀。     

大中型水电站机电工程质量全过程控制的主要措施

水电站机电工程质量控制,对确保按照设计质量要求生产供货、按照规范标准安装试验、确保电站安全稳定运行、提高经济收益有着重要的意义。但是,质量控制是一个系统全面、不断进步的工作,需要我们不断探索,不断进步。     

城市地下管网信息一体化成图作业方案的设计与实现

分析了城市地下管网信息的特点及数据源的获取方式,研究了系统的编码方法,设计了各数据文件的结构,对管网数据野外直接采集到内业一体化成图的作业方案进行了详细论述,并在"煤航2010管网信息处理系统"平台上进行了功能演示,获得了较好的效果。     

南水北调中线京石段金属结构设计回顾和总结

南水北调中线京石段应急供水工程金属结构设备较多,该项工程已经通过验收,并经过输水运行,金属结构设备运行正常。对金属结构设计进行回顾和总结,以利在今后类似的工程设计中进行改进和提高。     

The training of knowledge structures for manufacturing tasks: an empirical study

Abstract

Knowledge structure refers to the manner in which a human organizes knowledge with a given domain. Research has identified knowledge structure as a determinant of the human ability to perform cognitive-oriented tasks. Yet uncertainty still exists about how to improve an individual's cognitive task performance through the controlled utilization of the individual's knowledge structure. The purpose of this study is to investigate whether the development of individual's knowledge structure in a particular domain can be manipulated through training. The experiment utilized the manufacturing domain of plastic extrusion machine operation. Sixteen subjects, having no previous knowledge of the domain, were randomly assigned to one of two experimental groups. Each of the experimental groups corresponded to a distinct training condition. Over a three-day period, both training groups received the same instructional content; however, the sequence in which the training material was presented differed. One group initially received the abstract, conceptual relationships between domain concepts, followed by more detailed relationships associated with the lower level aspects of the domain. The other group received the training material in the reverse order; i.e. the lower level information followed by the abstract. Prior to and concluding the training sessions, each individual's knowledge structure was assessed along two dimensions, hierarchical levels and multiple relations, through a computer-based measurement technique.entitled KSAT. The group which received the abstract relationships first showed significant improvement following training along both dimensions of knowledge structure. No significant changes in the knowledge structure dimensions were found for the group which received the lower level relationships first. This study suggests that an individual's knowledge structure can be manipulated through training, with a significant effect being attributed to the training sequence of abstract material followed by the more detailed material.     

Participation of Danish and immigrant cleaners in a 1-year worksite intervention preventing physical deterioration

Worksite health promotion is seldom offered to workers who are low-educated and multi-ethnic, possibly due to an assumption that they are more reluctant to participate. Furthermore, little has been done to promote health at female-dominated workplaces. The main aim of this study was to investigate differences in participation among immigrant and Danish cleaners throughout a 1-year randomised controlled study tailored to cleaners and carried out in predominantly female workplaces. No significant differences in ethnicity were found in consent and participation throughout the 1-year intervention. Dropout was equally distributed among Danish and immigrant cleaners. This study indicates that a worksite health promotion intervention among a female-dominated, high-risk occupation such as cleaning can be equally appealing for Danes and immigrants. PRACTITIONER SUMMARY: This study provides insight about participation of Danish and immigrant cleaners in a worksite health promotion intervention in a predominantly female occupation. For attaining high participation and low dropout in future worksite health promotion interventions among cleaners, the intervention ought to not only target the ethnic background of the workers, but also to be specifically tailored to the job group.