纳米级铜粉改善润滑油抗磨性能的研究

在ＭＨＫ－５００型环块摩擦磨损试验机上,研究了纳米级金属铜粉（直径在１０￣５０ｎｍ）加入到矿物油中的润滑性能。结果表明,在低中滴动速度下（滑动速度分别为１．２８５ｍ／ｓ和２．５７ｍ／ｓ）,加有纳米级铜粉的润滑油表现出优良的抗磨性能。通过ＳＥＭ扫描电镜对磨痕形貌进行分析,提出了低滑动速度和高滑动速度下,纳米级铜粉分别以“垫片”和“滚珠”形态参与润滑。     

关于狄拉克函数

文章讨论了δ函数,给出了它的一个比较便于应用的定义,用它证明了基本Green函数满足广义Laplace方程。     

地下工程防水等级标准之我见──兼谈“国标”相关内容的不足

综述国内外地下工程和隧道的防水等级标准，并对我国现行标准有关内容进行评价。     

E36高强度船板钢的开发

介绍了湘钢宽厚板厂开发E36高强度船板钢的主要技术思路和工艺路线。通过合理的成分设计、钢水纯净度控制和控轧控冷工艺,得到钢质纯净、组织细化的E36级船板,使其具有优异的综合力学性能,满足了船级社的认证要求。     

双指标出矿管理方法在采场出矿中的应用

在无底柱分段崩落法的采场出矿管理中，采用出矿量和截止出矿品位两个指标来确定放矿截止时间，同时。应用磁化率仪测定夹石厚度和快速测定当次品位，实践证明，双指标出矿方法取得了较好的效果，能有效地防止丢矿和过贫化的现象。     

提高金堆城选铜指标的实践

介绍了近３年来金堆城华光实业总公司有色金属选矿厂采取技术措施,提高选铜指标的生产实践经验。     

油井水泥降滤失剂JZ-2

本文简要介绍了一种新的油井水泥降滤失剂ＪＺ２的合成，实验考察了加有ＪＺ２的Ｇ级水泥浆的性能，扼要报道了ＪＺ２在江汉油田两口油井固井中良好的使用效果。室内实验结果表明，ＪＺ２具有优良的控制水泥浆滤失的能力，与分散剂、缓蚀剂相容，对油井水泥的选择性小，加量为干水泥质量的１．２％—１．８％时，可使水泥浆的滤失量（６０—９５℃，７．０ＭＰａ，３０ｍｉｎ）由净浆的１５００—２０００ｍｌ降低到２００ｍｌ以下。     

What are the differences in driver injury outcomes at highway-rail grade crossings? Untangling the role of pre-crash behaviors

Crashes at highway-rail grade crossings can result in severe injuries and fatalities to vehicle occupants. Using a crash database from the Federal Railroad Administration (N = 15,639 for 2004–2013), this study explores differences in safety outcomes from crashes between passive controls (Crossbucks and STOP signs) and active controls (flashing lights, gates, audible warnings and highway signals). To address missing data, an imputation model is developed, creating a complete dataset for estimation. Path analysis is used to quantify the direct and indirect associations of passive and active controls with pre-crash behaviors and crash outcomes in terms of injury severity. The framework untangles direct and indirect associations of controls by estimating two models, one for pre-crash driving behaviors (e.g., driving around active controls), and another model for injury severity. The results show that while the presence of gates is not directly associated with injury severity, the indirect effect through stopping behavior is statistically significant (95% confidence level) and substantial. Drivers are more likely to stop at gates that also have flashing lights and audible warnings, and stopping at gates is associated with lower injury severity. This indirect association lowers the chances of injury by 16%, compared with crashes at crossings without gates. Similar relationships between other controls and injury severity are explored. Generally, crashes occurring at active controls are less severe than crashes at passive controls. The results of study can be used to modify Crash Modification Factors (CMFs) to account for crash injury severity. The study contributes to enhancing the understanding of safety by incorporating pre-crash behaviors in a broader framework that quantifies correlates of crash injury severity at active and passive crossings.     

基于JSP的成人教育成绩管理系统的设计与实现

根据高校成人教育的成绩管理特点,介绍了开发基于JSP的成人教育成绩管理系统的分析和设计过程;对系统安全性、数据库操作封装、用户口令加密、中文输出和Web服务器配置等实现系统的主要技术作了探讨.     

一种结合共同邻居和用户评分信息的相似度算法

随着互联网的发展,推荐系统逐步得到广泛应用,协同过滤(CF)是其中运用得最早.最成功的技术之一.CF首先根据用户间的相似度,找出每个用户的近邻;然后根据目标用户近邻的评分预测目标用户的评分;最后把预测评分较高的项目推荐给目标用户.因此相似度计算方法直接关系到预测结果的准确性,对推荐起着至关重要的作用.目前,学者们已从不同的角度提出了各种各样的相似度计算方法,其中共同邻居算法(common-neighbors)是一种简单有效的方法.但此法仅考虑了两用户间的共同邻居数,忽略了用户的具体评分信息.针对这个问题对共同邻居算法进行了改进,同时考虑了共同邻居数和用户的评分信息.实验结果表明,改进的共同邻居算法在一定程度上可提高评分预测的准确性.