What are the implications of climate change for trans-Atlantic aircraft routing and flight time?

The effect of wind changes on aircraft routing has been identified as a potential impact of climate change on aviation. This is of particular interest for trans-Atlantic flights, where the pattern of upper-level winds over the north Atlantic, in particular the location and strength of the jet stream, strongly influences both the optimal flight route and the resulting flight time. Eastbound trans-Atlantic flights can often be routed to take advantage of the strong tailwinds in the jet stream, shortening the flight time and reducing fuel consumption. Here we investigate the impact of climate change on upper-level winds over the north Atlantic, using five climate model simulations from the Fifth Coupled Model Intercomparison Project, considering a high greenhouse-gas emissions scenario. The impact on aircraft routing and flight time are quantified using flight routing software. The climate models agree that the jet stream will be on average located 1° further north, with a small increase in mean strength, by 2100. However daily variations in both its location and speed are significantly larger than the magnitude of any changes due to climate change. The net effect of climate change on trans-Atlantic aircraft routes is small; in the annual-mean eastbound routes are 1 min shorter and located further north and westbound routes are 1 min longer and more spread out around the great circle. There are, however, seasonal variations; route time changes are larger in winter, while in summer both eastbound and westbound route times increase.     

中国至尼泊尔跨境铁路最大坡度研究

中国至尼泊尔跨境铁路穿越喜马拉雅山脉,具有显著的地形高差,海拔从佩枯错4 600 m急骤下降至加德满都1 360 m,部分地段自然纵坡达50‰及以上,需要采用较大坡度以适应地形。在分析国内外大坡度铁路使用及发展的基础上,结合项目地形特点对坡度方案进行分段研究,重点对佩枯错至加德满都段最大坡度方案从运输安全性、运输质量、运输能力和运输经济性等方面综合分析论证。结合长大下坡紧急制动距离的要求,分析客货列车下坡限速,考虑牵引力、制动力、黏着力和车钩强度等限制条件,检算满足长大坡道客货列车牵引、制动安全的牵引质量和编挂辆数,并结合运输需求分析不同坡度方案能力适应性,通过模拟牵引计算比较列车运行速度,计算工程投资、机车购置费和运营费的费用现值,进行经济性比较。综合分析,本项目最大坡度日喀则至佩枯错段暂推荐采用13‰,佩枯错至加德满都段采用30‰。     

车辆段5T、AEI探测站维修作业通道开设方式探讨

本文针对铁路全封闭后,车辆段5T、AEI探测站维修人员进出困难的问题,提出了设置探测站作业通道需遵守的三条原则。归纳了栅栏直开、探测站双开门、围墙开门三种探测站作业通道的开设方式,比较各自优缺点和适用条件。建议在既有探测站增设作业通道时,需因地制宜,选择合理方案。在新建探测站工程时应同步进行作业通道的设计和施工。     

浅析呼和浩特西站计算机联锁改造

本文介绍了呼和浩特西站(DS6-K5B 计算机联锁系统)与呼和浩特站增加三线工程改造施工的相关过程和经验,重点阐述了大型站场含控制台改造需要注意的问题。     

本体论在军事信息系统建模中的应用研究

系统建模是复杂信息系统分析和设计的关键。本休论作为一种语义信息建模方法，对解决知识的“共享”和“重用”问题具有巨大潜力。在C^4ISR系统的建设过程中采用信息系统建模方法，尤其是引入本体论，对于C^4ISR系统综合集成具有重要意义。通过辨析信息系统、系统建模、本体论的概念，分析了IDEF5方法，对本体论在C^4ISR系统建模中的应用进行了探讨，并讨论了C^4ISR系统本体描述语言。     

海上风电安装船的发展趋势研究

随着海上风力发电产业的迅速发展,风电安装船需求越来越大,并且风电安装船是高附加值工程船,因此这一市场的吸引力将越来越受到造船界重视,竞争将越来越激烈,但海上风电场施工成本高、海上作业时间长及工期长等问题的存在延缓了海力发电产业的发展。因此,本文将着重对海上风电结构物施工、安装过程的单一海工设备发展进行浅析,为探索深水化、大型化、专业化、集成化的海上风电安装船来完成深海域基础施工及风机安装问题提供设计参考。     

船用反应堆主冷却剂泵建模研究与仿真

本文依据船用反应堆主泵试验数据,绘制了基于RELAP5程序的主泵全特性曲线,利用建立的数学仿真模型对主泵启动特性、惰转特性、稳态运行工况、高低速切换工况的响应过程进行分析。结果表明：主泵模型能够实现相应的仿真功能,较为准确地反映主泵的运行特性;船用主泵对转动惯量的要求较高;模型适用于后续对反应堆系统不同响应的分析,并可为主泵的设计及优化提供参考。     

北京地铁5号线折返追踪间隔分析

在城市轨道交通运行系统中,列车在折返区域的追踪间隔是单条线路提升运力的瓶颈.分析北京地铁5号线折返追踪间隔,以实现“列车2 min运行间隔”的目标.首先根据现场实测数据分析5号线列车在折返区域中的进站追踪能力、折返追踪能力和出站追踪能力,进而计算列车在折返区域的最小运行间隔;其次,基于列车运行图编制理论提出通过缩短列车站停时分、出入库时分、转台时分来减小列车折返追踪间隔的方法;最后,结合北京地铁实际的运营管理经验,从系统设计角度提出缩短城市轨道交通列车折返追踪间隔的技术手段和措施.     

羟基红花黄色素A对MPP~+诱导的SH-SY5Y细胞凋亡的保护作用

目的观察羟基红花黄色素A(HSYA)对MPP+诱导的SH-SY5Y细胞凋亡的保护作用,并探讨其作用机制。方法采用MTT法检测细胞存活率,流式细胞术检测细胞凋亡率;二乙酸二氯荧光素盐(DCFH-DA)法检测细胞内活性氧(ROS)含量;罗丹明123(Rhodamine123)染色法检测细胞线粒体膜电位;Western blot法检测Cyt-C、Bcl-2、Bax、Caspase-3和Caspase-9的表达。结果 1mmol/L MPP+处理SH-SY5Y细胞48h后,细胞存活率显著降低,并诱导细胞产生凋亡,凋亡率达(38.6±1.8)%。而HSYA(15、60、120μmol/L)预处理1h,可明显增加SH-SY5Y细胞存活率(P<0.001),并能有效抑制MPP+诱导的细胞调亡(P<0.01);可明显抑制MPP+诱导的细胞内ROS的增加(P<0.001);也能有效抑制MPP+诱导的细胞线粒体膜电位的降低(P<0.01)。120μmol/L HSYA预处理能显著性增加Bcl-2/Bax比值(P<0.01);能够明显抑制MPP+诱导的胞质Cyt-C的释放(P<0.05)和Caspase-3、Caspase-9的高表达(P<0.05,P<0.05)。结论 HSYA预处理能明显提高MPP+诱导的SH-SY5Y细胞损伤的细胞存活率,可有效抑制细胞调亡的发生,其机制可能与抑制细胞线粒体凋亡途径有关。     

Direct electrochemical extraction of Ti5Si3 from Ti/Si-containing metal oxide compounds in molten CaCl2

Direct electrochemical extraction of Ti₅Si₃ from pressed cathode pellets comprising of powdered Ti/Sicontaining metal oxide compounds was investigated by using molten salt electro-deoxidation technology.Three groups of mixtures including TiO₂ mixed with SiO₂,Ti-bearing blast furnace slag（TBFS） mixed with TiO₂, and TBFS mixed with high-titanium slag（HTS） were prepared at the same stoichiometric ratio（Ti:Si=5:3） corresponding to the target composition of Ti₅Si₃,and used as the starting materials in this experiment,respectively. The pressed porous cylindrical pellet of the Ti/Si-containing compounds served as a cathode,and two different anode systems,i.e.,the inert solid oxide oxygen-ion-conducting membrane（SOM） based anode system and graphite-based anode system were used contrastively.The electrochemical experiment was carried out at 900-1050℃and 3.0-4.0 V in molten CaCl₂ electrolyte.The results show that the oxide components were electro-deoxidized effectively and Ti₅Si₃ could be directly extracted from these complex Ti/Si-containing metal oxide compounds.