基于改进蚁群算法的跨境电商物流网络优化——以X快递公司为例

本文基于改进蚁群算法,针对X快递公司跨境电商物流网络进行优化研究。从物流网络承载能力和跨境物流网络优化两要素出发,构建多约束条件下的承载能力模型,并提出优化模型以降低成本、提升效率。通过算例验证模型有效性,为跨境电商物流网络优化提供新思路,增强企业在激烈市场竞争中的物流优势。     

开发与推广相结合加快电动汽车实用化

介绍了电动汽车目前的技术水平与距离实际使用的差距,以及电动汽车的关键技术－蓄电池,电动机,电量指示器,充电器车身总成技术现状发展趋势。论述了开发与推荐相结合是加快电动汽车实用化的捷径,建立了示范试验区是推广的必由之路,介绍了国外电动汽车示范试验区积累的宝贵资料,并对电动汽车与传统汽车的购置,使用费用进行对比,结论是电动汽车折购置费用高一些,两种车辆的使用费用相当。     

南京南站到发线运用方案对京沪高速铁路列车追踪间隔时间的影响分析

本文基于车站进路一次解锁及分段解锁的不同情况,重点研究了南京南站到发线运用方案对京沪高速铁路列车出发及到达追踪间隔时间的影响.在分析到发线运用方案对列车追踪间隔时间影响机理的基础上,对南京南站所有到发线运用方案下的列车追踪间隔时间进行检算.检算结果表明:到发线运用方案主要影响进路分段解锁下的南京南站列车到达追踪间隔时间...     

编组场尾部车辆溜放仿真系统的研究

为了确切地描述编组场尾部货车溜放的运动规律，为科学、合理地制定防溜器的安装方案提供依据，根据车列纵向动力学的方法，分析了车列溜放过程中存在的各种纵向力，采用面向对象模块化设计方法编制了编组场尾部货车溜放仿真软件。本系统的开发实现了实时模拟各种工况下货车溜放过程。     

Serum concentrations of laminin and fibronectin in patients with acute coronary syndromes

Objective To study the serum iaminin (LN) and fibronectin (FN) changes in acute coronary syndromes (ACS), and explore the role of them in assessing the severity of ACS. Methods This study included 46 ACS patients [25 with acute myocardial infarction (AMI) and 21 with unstable angina (UA)], 51 stable angina (SA) patients and 47 people without CHD as controls. Serum levels of LN, FN, fibrinogen and blood fat were assessed. Coronary angiography were performed on 49 of them. Results The serum concentration of LN was lower in ACS patients [(85.20±27. 57)ng/mL], higher in SA patients [(116. 80 ± 28. 80)ng/mL] as compared to that in the control group [(100.06±29.96)ng/mL], with significant difference among the groups (P<0.05). No difference was found in FN among the three groups. However, the subgroup analysis in the group with ACS showed that the serum concentration of FN was significantly higher in UA patients [(229.60±121.39)μg/mL ], and lower in AMI patients [(108.31±47.12) μg/mL ]. The serum LN and FN concentration could respectively enter the logistic regression equations of ACS patients and US patients. Neither LN nor FN concentration was correlated with narrowing of coronary artery of angiography. Conclusion Serum LN and FN level may be a useful indicator for stability of atherosclerosis plaque in coronary arterial disease patients, but could not predict the extent of narrowing in coronary angiography.     

AES算法及其实现技术

章在简述AES算法产生背景的基础上对算法进行了分析,对算法的具体实现方法进行了说明,给出了算法的测试数据。最后,采用分割运算的方法对算法的并行处理性能进行了估测。     

『天蝎号』核潜艇遇难之谜

1968年5月的一天,美国的一艘“巨无霸”核攻击潜艇突然神秘失踪,关于它的失踪原因在三十多年来一直争论不休。直到这艘核潜艇失踪数十年后的今天,美国《知情者》日报最近隆重推出一颗重磅“原子弹”——揭开美国海军“天蝎号”核潜艇遇难之谜。