空气冲旋钻头牙齿失效分析与新材料实验研究

针对目前空气冲旋钻头钻进中牙齿频繁断裂、脱落以及磨损严重，导致破岩效率低、使用寿命短等问题，采用纳米改型技术，在硬质合金中掺杂纳米Al₂O₃制备出Al₂O₃/WC Co纳米/微米复合材料，对其性能、组织结构进行分析，对其耐磨性、耐冲击性进行实验研究，结果表明：加入3%的纳米Al₂O₃并添加适量的抑制剂和稀土元素能明显改善Al₂O₃/WC Co纳米/微米复合材料的组织结构、细化晶粒，复合材料的耐磨性和耐冲击性能得到大幅提高，较硬质合金YG8提高4～8倍。为大幅度提高钻头破岩效率，延长钻头使用寿命提供了可能性。     

Disagreement in Australian partners’ reports of financial difficulty

We use unique data in which both partners report about household finances to demonstrate that there is often disagreement about whether the household has experienced financial difficulty in the past year. Four alternative explanations for this disagreement are tested using the data. The results indicate that disagreement may be related to the severity of the underlying material hardship rather than to gender differences or individual (as opposed to household) views of financial difficulty. We find limited evidence that for some couples information asymmetries contribute to explaining disagreement about financial difficulty. This implies that standard surveys which collect information about the household’s financial position from a representative individual may fail to completely characterize the nature of material hardship.      

燕京大学外籍教师文献档案的研究与利用

燕京大学是近代中国颇具影响的教会大学,由于历史原因,海内外学者对记载燕京大学外籍教师活动的资料发掘很不够,直到20世纪80年代以后,国内外学者对燕京大学外籍教师的史料才开始重视起来,并且成果丰硕。充分发掘和利用燕京大学外籍教师史料,有助于燕京大学校史研究,有助于客观分析燕京大学外籍教师在北京近代教育史上的作用,有助于为当代教育改革提供借鉴。     

证据的可反驳性——对高科技证据材料的防御

由于高科技证据材料所具有的特点,其容易造成在实体方面认识论常规错误的发生,以及程序方面剥夺被追诉人程序权利的危险,有鉴于此,应当在证据能力和证明力之外建立证据＂可反驳性＂的新属性,以防止上述危险进入刑事诉讼程序。     

《电厂金属材料》课程教学改革初探

通过对《电厂金属材料》这一课程教学现状的初步分析,认为该课程的教学必须更新观念,优化内容,转变体系,在教材建设、教学手段等方面作一些相应的改革.     

马克思主义地理环境论与区域生态文明建设

马克思主义地理环境论应该包括马克思恩格斯人与自然、人与社会关系的理论和自然-人-社会相互作用的物质变换理论以及从普列汉诺夫地理环境论到科学发展观等马克思主义继承者的理论成果。构建区域生态文明的过程既需要上述理论助力顶层设计宏观决策,又离不开它进行具体问题具体分析攻坚克难。具体而言就是,需要在马克思主义地理环境论的指导下,从区域自然地理环境和社会人文环境实际出发,注重区域空间的平衡稳定、区域主体的和谐共生、区域资源的科学配置,从而创造出自然-人-社会“三位一体”的全新的生态文明主体的存在方式和生活方式。     

学籍管理在研究生教育质量保证体系中的重要作用

文章从突出学生主体地位,适应学生个性发展的学籍管理先进理念;从"输入-过程-输出"的学籍 管理流程遵循的严格制度;从为实现快捷、准确、长效的学籍管理目标而采用的计算机现代技术等三个方 面,阐述了学籍管理对研究生教育质量提高的重要性及加强和改进学籍管理的必要性。     

Planned Lead Times in Multistage Systems

This study investigates the impact of planned lead times on performance in multistage manufacturing where material requirements planning is used in a make-to-stock environment. We simulate a variety of different operating environments and find: (1) planned lead times are important to customer service levels under all operating environments examined, but have a smaller impact on inventory investment; (2) tight due dates introduced by short planned lead times hurt customer service without saving much inventory; (3) small increases to tight planned lead times improve customer service substantially with small inventory increases; (4) co-component inventories change with planned lead times, and disparity between such inventories is a sign of poor timing coordination; (5) the fixed order quantity rule performs better than the periodic order quantity rule; and (6) tall product structure and large lot sizes require particular attention to planned lead times. The findings also extend the current understanding of planned lead times by including uncertainties such as forecast error, yield loss, and equipment reliability. The study concludes with a way to diagnose and improve poorly set planned lead times.     

Simulation Analysis of a Manufacturing Supply Chain*

A supply chain is a series of manufacturing plants that transform raw material into finished product. A pipeline within a supply chain refers to the stream of information, material, components, and assemblies that are associated with a particular product. It is typical for manufacturing plants to put considerable effort to optimize the performance of a horizontal slice of a supply chain (such as coordination among parts that share a common resource). The need to optimize the performance of the vertical slice (the supply chain connecting raw material to finished product) by controlling the transmission of schedule instability and the resulting inventory fluctuation is often overlooked. A schedule is stable if actual production requirements for a given period do not change from the forecast production requirements. Stable production schedules are important when managing supply chains as they help control inventory fluctuation and inventory accumulation. Failure to control schedule instability results in high average inventory levels in the system. In this paper a simulation analysis of supply chain instability and inventory is conducted, and it is shown how supply chains can be analyzed for continuous improvement opportunities using simulation. The focus is on a stamping pipeline in an automobile supply chain based on operating data from General Motors (GM). It is shown that the techniques used in this paper are a useful tool for supply chain analysis.     

论形上迷失与异化劳动

形上迷失即终极关怀的缺失,它的内在原因是人的意识,但意识在人类诞生之初仅提供给形上迷失以先在的前提条件,真正导致形上迷失产生的是把人类从他的物质家园———自然中分离出去的异化劳动。在异化劳动的推动下形上迷失跨越史前时代、古代文明和轴心期这三个历史阶段,从偶然的可能开始经由现实的可能最终达到其完全的现实。与此同时在轴心期,人类的精神家园也随之而彻底建立。