全再生快速修补混凝土的制备及性能

根据修补区混凝土可开放交通的要求,优选出全再生快速修补混凝土最优配合比,并与常用的再生粗骨料快速修补混凝土进行比较.结果表明,全再生快速修补混凝土的抗压强度和粘结强度较易满足要求;其最优化配合比参数为:胶凝材料总量为500 kg/m3,再生细骨料在细骨料中掺量为30％,而其砂率为35％;其干燥收缩略大于常用的再生粗骨料快速修补混凝土,但显著提高了其抗氯离子渗透性能.     

我国煤巷机械化掘进机现状及锚杆支护技术

介绍了我国煤巷机械化掘进机和支护技术的现状，全面阐明煤巷快速掘进、煤巷锚杆支护技术是高效集约化矿井建设的关键性配套技术，进而指出煤巷机械化快速掘进技术的发展趋势。     

Rapid,Label-Free Prediction of Antibiotic Resistance in Salmonella typhimurium by Surface-Enhanced Raman Spectroscopy

The rapid identification of bacterial antibiotic susceptibility is pivotal to the rational administration of antibacterial drugs. In this study, cefotaxime (CTX)-derived resistance in Salmonella typhimurium (abbr. CTX^r-S. typhimurium) during 3 months of exposure was rapidly recorded using a portable Raman spectrometer. The molecular changes that occurred in the drug-resistant strains were sensitively monitored in whole cells by label-free surface-enhanced Raman scattering (SERS). Various degrees of resistant strains could be accurately discriminated by applying multivariate statistical analyses to bacterial SERS profiles. Minimum inhibitory concentration (MIC) values showed a positive linear correlation with the relative Raman intensities of I₉₉₀/I₁₃₄₈, and the R² reached 0.9962. The SERS results were consistent with the data obtained by MIC assays, mutant prevention concentration (MPC) determinations, and Kirby-Bauer antibiotic susceptibility tests (K-B tests). This preliminary proof-of-concept study indicates the high potential of the SERS method to supplement the time-consuming conventional method and help alleviate the challenges of antibiotic resistance in clinical therapy.     

模具装配车间生产调度规则的研究

装配车间(Assembly job shop)问题是一类具有工序次序约束、装配次序约束以及资源能力约束等多种约束的组合优化问题。而且制造型企业机械加工车间的设备往往存在日可用时间的约束,工件随加工顺序的不同,其实际的设备占有时间可能发生变化,增加了制定生产调度计划的难度。以提高模具装配车间的生产效益为目标,提出了在装配车间中考虑设备日可用时间约束的优先调度规则,并通过仿真实验验证所提出调度规则对各评价指标具有较优的结果。     

A molten metal jet impingement on a flat spreading surface

ABSTRACT

In the event of a severe accident, past experiences such as Three Mile Island and Fukushima Daichi have shown that the reactor core of a light-water nuclear reactor, if not properly safeguarded, could go through a meltdown. This will be followed by the formation of a corium, a mix of molten fuel elements, and liquid metals from the Reactor Pressure Vessel (RPV). In the worst-case scenario, a melt through from the RPV can occur and lead to the spreading of the corium, in the form of a molten element’s jet impinging on a flat concrete structure of the Primary Containment Vessel (PCV). To enhance the decommissioning and the safety procedure, scope of the present article is to deepen the understanding of the phenomena involved in the mentioned scenario, mainly jet-instability and molten material spreading. In the present study, experiments were carried out, by using corium simulant materials such as Copper and Tin, to investigate the link between the instability of the gravity-driven molten metal jet and the impinging followed by its spreading over a flat area.     

基于决策树的堆芯物理参数预测研究

反应堆堆芯核设计涉及大量方案的搜索与详细计算,缩短方案搜索时间有利于提高核设计效率。数据挖掘技术通过对大量数据进行学习与模式识别,可实现核设计方案物理参数的快速预测,更快地筛选出可行的备选堆芯方案。本文基于数据挖掘的决策树4种算法：C4.5、RepTree、Random Forest及Random Tree,在计算时以燃料富集度、含可燃毒物燃料棒数量及含量作为自变量,以寿期内k_eff不均匀系数偏差（KUCD）、径向功率不均匀系数偏差（RPNCD）、径向中子通量不均匀系数偏差（RFNCD）、堆芯寿期（CL）作为目标函数,构成目标函数符合度（CPF）,利用大量已知核设计参数的组件及堆芯设计方案作为数据挖掘训练集,构建数据挖掘模型,并用于对未知核设计参数的组件方案集合（测试集）进行CPF快速预测。结果表明,4种算法利用训练集构建数据挖掘模型的时间在0.6 s以内,各算法的交叉验证精度均在0.7以上,其中C4.5算法对CPF预测精度最高;对测试集方案的核设计参数预测中,单个方案的预测时间均在0.9 s以内,而Random Forest算法对CPF等于4的预测效果最好。     

基于Moldflow和UG的手机前盖模具设计

根据手机前盖的结构特点和质量要求,运用Moldflow软件对产品浇注系统、冷却系统进行优化设计。通过正交试验,分析了注射工艺参数对产品体积收缩率和翘曲变形的影响规律,得到优化注射工艺方案。根据Moldflow分析结果,利用UG软件完成产品的模具设计。     

快速检测技术在食品监测中的研究进展

快速检测技术与传统检测方法相比,具有检测时效快、检测方法简单等优点,其在保障食品安全中起到非常重要的作用。文章重点叙述了食品中化学有害物质、微生物、农药残留、重金属离子的快速检测技术的研究进展。     

新产品创意对快速原型的需求评价

由于需求的多变性、模糊性以及多样性的特点,使得新产品创意与市场需求之间存在一定的差距.为了实现新产品概念商业化的成功,产品创意必须再次回到市场需求问题上来,并经过需求评价等方法进一步完善与发展.本文结合设计实例,阐述了快速原型在问题评价时激发创造性思维中所起到的作用.     

镁及镁合金的防护处理现状分析

综述了镁及镁合金防护存在的问题、影响因素及防护方法。对镁合金表面防护包括化学转化膜、阳极氧化、金属镀层等技术所涉及的理论基础及存在问题进行了概括与分析。并对镁合金耐蚀性研究的发展趋势作了展望。