Formation of nanometer coherent structures during spinodal decomposition and ordering coexistence phase transformation in Fe-24Al alloys

The nanometer coherent structure evolution of spinodal decomposition and ordering coexistence phase transformation in Fe-24Al alloys is investigated by the microscopic phase field kinetic model. The results show that the concentration and long-range order parameters all continuously change towards to their equilibrium values during phase transformation. With the increase of elastic interaction energy, the anisotropy along [01] or [10] elastic soft direction is more obvious and the time reaching equilibrium state is also shortened. According to the results, the formation of nanometer coherent structures during phase transformation is composed of the initial decreasing stage of order degree stage, the incubation stage, the continuous increasing stage of concentration order parameter and long-range order parameter, and the later stable stage. The spinodal decomposition and ordering is interaction; the initial ordering stage is a necessary condition of the coexistence phase transformation. The nanometer coherent structures are not found to grow during the whole phase transformation. The simulation results are in accordance with the results in experiment obtained by the aging treatment in Fe-24Al alloys.     

基于G.8032的二层以太环网两点故障保护方案研究

ITU-T提出了以太网环网保护切换的方案,即G.8032标准.该标准采用备用链路的方法,当故障发生时,开通备用链路.但是,该标准只针对一点故障的保护,对于两点故障的保护能力还是空白,本文主要讨论基于G.8032标准的两点故障的保护.     

汽车零部件物流越库配送系统的多重响应优化

提出了一种离散动态系统仿真和响应面元模型相结合的优化方法,对汽车零部件物流越库中心内部设计的多重绩效(零部件吞吐量与平均运作时间)进行优化.在越库中心实际运作的基础上,借助Arena模拟越库的内部运作流程,选取一部分重要内部构件作为系统绩效的设计变量,根据仿真实验的结果拟合出吞吐量和运作时间的响应面元模型,识别出越库中心设计的关键因子,并找出3种目标下最大化绩效的因子组合.优化结果表明,优化后的越库能大大改进系统绩效,所采用的方法可用于零部件的越库实践.     

Experimental study on mechanical properties of weathered rock covered by loess

Based on dynamic triaxial test, the mechanical properties of the weathered rock covered by loess were studied. The cohesion value of weathered mudstone is far below that of the weathered sandstone, while the internal friction angle values are basically equivalent, about 30°. Compared with the undisturbed sample, the cohesion value of remodeling weathered rock sample decreases significantly. With the increase of moisture content, the strength of weathered mudstone is obviously decreased due to the influence of the water softening effect. This results illustrate that the bearing stratum is not easily affected by external disturbance in comparison to weathered mudstone. In the engineering, in order to ensure the good mechanical properties of the soil, more attention should be paid to keeping the water content constant, even to reducing the water content. The experiments show that the relations between shear stress and strain of weathered rock were nonlinear and the behavior of weathered rock can be expressed by the hyperbolic model. The initial modulus of undisturbed weathered rock, under the same consolidation conditions, is much greater than that of remodeling samples. Meanwhile, the initial dynamic elastic modulus of sandstone is also greater than that of the mudstone. The dynamic shear modulus ratios of the undisturbed sandstone, the undisturbed mudstone, as well as the remodeling mudstone have the normalization characteristics with the increase of dynamic shear strain. The damping ratio of mudstone is larger than that of the sandstone, and the damping ratio of remolding sample is also greater than that of the undisturbed mudstone. The mudstone has the bad mechanical properties as bearing stratum.     

课程改革引领下的汽车专业实训基地建设探讨

<正>实训基地建设是职业院校基础能力建设的重要组成部分,是职业院校培养技术技能型专门人才的必备条件。以课改思想来指导实训基地建设,以"七个合一"课改理念来组织实训基地建设,必将推动职业院校又好又快发展,为地方经济发展提供高素质劳动者和优秀专业人才。2005年江苏省教育厅制定出台了《江苏省职业教育课程改革行动计划》,标志着新一轮江苏职业教育课程改革工     

吊舱式电力推进船舶螺旋桨匹配设计仿真研究

在国内,吊舱推进器的设计还处于理论起步阶段,尤其是吊舱推进器螺旋桨,其设计方法尚未成熟,而螺旋桨的设计对于整个推进系统推进性能的影响又尤为关键,关系到船—机—桨匹配的综合推进性能。为此,采用常规螺旋桨敞水特性图谱等效设计POD螺旋桨参数的方法对吊舱推进器螺旋桨进行设计,分析吊舱式推进船舶船—机—桨的匹配性能。为了提高设计效率及优化推进系统的推进性能,针对吊舱式电力推进船舶,采用常规螺旋桨等效设计方法设计POD螺旋桨参数,同时基于LabVIEW图形化编程语言开发船—机—桨匹配数值分析软件以对设计参数进行静态匹配计算,并与母船的推进效率进行对比,选取最优化的螺旋桨参数作为POD螺旋桨参数,以优化推进效率。研究结果表明：采用常规螺旋桨等效设计方法设计POD螺旋桨参数的方案,同时结合开发的船—机—桨匹配数值仿真分析平台,可以方便、快捷地对吊舱式推进船舶进行船—机—桨匹配分析计算比较,提高推进性能。     

堆石混凝土技术在水运工程中的应用

堆石混凝土技术以其低水化热、施工工艺简便、施工效率高、施工质量高等优势广泛应用在水利水电工程混凝土结构施工中,但在水运工程存在有大体积混凝土结构部位（如胸墙）中却很少得到应用。文中以黄骅港围堰二期工程为例,从施工方案设计、综合评定分析等方面介绍了堆石混凝土技术在该工程中的成功运用,优势明显。本工程也为堆石混凝土技术应用在水运工程敲开了大门,前景宽广。     

铁路分局货车动态分析系统

针对铁路分局货车统计的现状,设计开发了站-段-分局三级统计应用系统,实现了分局货车甩挂、在途和运行分析等的计算机处理,同时为通用系统提供了统计数据源.     

关于公路桥梁日常养护管理的思考

长期以采,我国公路桥梁管理中一直存在着"重建设、轻养护"这个问题.由于日常养护管理不到位,在日趋增大的车辆荷栽作用下,很多桥梁技术状况快速下降.针对由伸缩缝引发的桥梁典型病害进行分析,提出加强日常养护管理的建议,对于公路桥梁的日常养护管理具有参考价值.     

氯化两面针碱诱导人肝癌细胞SMMC-7721凋亡的研究

目的 研究氯化两面针碱诱导人肝癌细胞SMMC-7721凋亡的作用.方法 采用噻唑蓝(MTT)比色法检测人肝癌细胞SMMC-7721生长活力;Hoechst33258核染色,观察细胞形态学变化;流式细胞仪检测细胞周期及细胞凋亡率.结果 氯化两面针碱作用于细胞后,在体外呈浓度、时间依赖性显著抑制SMMC-7721细胞的生长,作用24、48、72h的半数抑制浓度(IC50)分别为(19.5±1.8)、(3.8±0.2)、(2.8±0.1)mg/L;Hoechst33258染色后,可见核染色质凝集,凋亡细胞呈致密浓染,与对照组相比,氯化两面针碱处理后凋亡细胞比例增加;流式细胞仪检测到G2/M细胞比例增加,G0/G1、S期细胞比例下降.药物作用于SMMC-7721细胞后,随浓度增加细胞凋亡率增加.结论 氯化两面针碱对SMMC-7721细胞有明显的生长抑制作用,可能与改变细胞周期并诱导细胞凋亡有关.