科创中国

By recording nocturnally migrating passerines with tracking radar we have investigated how coastlines affect the migrants' flight paths. Birds could use coastlines as an orientation aid or as a reference cue to compensate for wind drift while mi- grating. However, on the small scale of Falsterbo Peninsula in southern Sweden, we found very little effect of coastlines on migrants flight paths, irrespective of altitude. We tracked 2 930 migrants in three autumn and two spring seasons, at altitudes from 60 up to 3 000 meters. We compared tracks of migrants flying in three different areas, which correspond to the three main coastlines, and can demonstrate that the orientation of the tracks did not differ in a way consistent with the coastlines between the areas in autumn, and showed only a slight effect in spring. This is in accordance with earlier infrared device monitoring in Falsterbo, but contrary to earlier visual observations. It supports the view of nocturnally migrating passerines as mainly broad-front migrants. Even though the coastlines on the scale of the peninsula affected the flight paths very little, it is possible that the coastline has an effect on a larger regional scale, by migrants avoiding long sea crossings and thereby being funneled towards the peninsula, but this remains to be investigated [Current Zoology 60 (5): 660-669, 2014].

目的:测定飞行员长时间(8h)模拟飞行时,佩戴飞行头盔对其飞行耐力的影响,为飞行头盔设计改进和使用提供依据.方法:按受试者佩戴头盔的重量(1.7kg与2.0 kg)和任务负荷(仅提供影视音乐节目与模拟航线飞行)的不同将试验分为3组,观察记录受试者的主诉和表现.结果:受试者反映的问题,主要是闷热和压痛.为减轻闷热和压痛,受试者不断地调整头盔.闷热、压痛和调整头盔频次与时间进程相关,闷热出现在1h-3h,压痛出现在4-7h.因头盔重量和任务负荷不同,各组受试者的主诉和调整头盔频次有显著性差异.结论:头盔重量以及任务负荷等对飞行耐受能力有重大影响:头盔增重、任务负荷增加,加快了闷热和压痛的生成.频繁地调整头盔是缓解闷热和压痛的主要行为表现.相关测量结果为飞行头盔设计改进和使用提供了重要依据.

In order to compare the two species' flight performance over the exposed and windy Falsterbo Peninsula, where thermal conditions seldomly are very favorable, we used tracking radar to study flight parameters of sparrowhawks Accipiter ni- sus and common buzzards Buteo buteo during autumn migration. The results showed a clear difference between sparrowhawks and common buzzards in their flight altitudes and speeds, and in the wind conditions they encountered. Common buzzards had higher flight altitudes and were more selective of wind. Flight altitude was negatively related to the wind speed, which was most pronounced for common buzzards. Sparrowhawks had higher mean air- and cross-country speeds than common buzzards. Air- speed was negatively related, whereas ground and cross-country speeds were positively related to the tailwind component for both raptors. The differences between sparrowhawks and buzzards could to a large degree be explained by a larger dependence on thermal soaring among the common buzzards; a strategy associated with selectivity for favourable thermal and wind conditions during migratory flight. An additional important explanation for the interspecific differences was the habit of the sparrowhawks to combine migratory flight with hunting for prey, which makes it prone to fly at lower altitudes and use flapping flight to a much larger degree than common buzzards which do not forage during their migratory passage of the Falsterbo Peninsula [Current Zoo- logy 60(5): 670-679, 2014].

随着我国通用航空的发展,私人飞行员数量近年来从无到有并呈快速增长趋势.对于这一新的航空活动参与群体,为了在保证其飞行安全的同时保证公众安全,并促进其发展,本文研究其发展现状及目前政府监管上存在的问题,并提出监管对策建议.本文通过大量调研访谈得到目前我国私人飞行员发展现状,对比美国政府监管模式及我国道路交通安全管理模式,提出应修订相关法律规章相关内容及改进政府监管模式;鼓励行业协会的发展;加强政府对社会公众的航空安全教育与沟通.

Satellite-tracking technology has allowed scientists to make a quantum leap in the field of migration ecology. Nowadays, the basic description of migratory routes of many species of birds has been reported. However, the investigation of bird migration at individual level (i.e. repeatability in migratory routes and timing) still remains seldom explored. Here, we investigated repeated migratory trips of a trans-Saharan endangered migratory raptor, the Egyptian Vulture Neophron percnopterus, tracked by GPS satellite telemetry. We compared between- and within-individual variation in migratory routes and timing in order to assess the degree of repeatability (or conversely, the flexibility) in migration. To this end, we analysed a dataset of 48 trips (23 springs and 25 autumns) recorded for six adult birds during 2007-2013. Our results showed consistent migration timing at the individual level, both in spring and autumn. Interestingly, there was a high degree of flexibility in the routes followed by the same individual in different years, probably due to variations in meteorological conditions. Contrary to expectations of a faster migration in spring than in autumn owing to a time-minimization strategy for breeding, birds spent less time in autumn migration (13 ± 2 days, range = 9-18 d) than in spring migration (19 ± 3 days, range = 13-26 d), which can be explained by differences in environmental con- ditions en route. Egyptian vultures showed a consistent clockwise loop migration through western Africa, following more easterly routes in autumn than in spring. Finally, our results provide supporting evidence of low phenotypic plasticity in timing of migration (i.e. strong endogenous control of migration) and high flexibility in routes [Current Zoology 60 (5): 642-652, 2014].

针对深空通信延时非常大的特点,提出了一种基于喷泉编码和并行路径的无反馈数据传输协议,该协议能够避免发送端和接收端之间反复的握手过程,缩短数据传输时间.同时通过在发送端和接收端之间部署多个中继,建立并行传输路径保证数据能够连续传输,克服单一路径易受链路中断影响的缺点,达到充分利用链路资源的效果.仿真结果表明,只要采用编码开销比链路丢包率稍微大一点的喷泉码就能保证数据在接收端以极高的概率准确恢复;增加并行传输路径的数目可以提高传输容量,减小传输所用时间.

汽车行驶速度是公路设计指标的重要依据,更是道路交通安全的重要因素.然而.近年来随着我国高速公路通车里程的增加,公路设计人员的实践经验逐渐年积累,意识到现行路线设计规范采用的计算行车速度方法已不能真实反映我国交通的实际运行特性,无法保证线形标准的协调一致性,存在一定的安全隐患.为进一步保障和提高我国公路的行车安全,交通部颁发了《公路项目安全性评价指南》,初步提出了对我国公路安全性评价的内容、方法和标准,从行车安全性的角度要求高速公路和一级公路需进行公路安全性评价,以达到减少交通事故,降低交通事故危害的目的.本文正是基于这一条件,针对公路线形连续是保证汽车安全行驶的基本要素,结合某高速公路初步设计阶段,应用《公路项目安全性评价指南》中的运行速度协调性与设计速度与运行速度协调性,分析计算高速公路初步设计阶段的平、纵面线形设计的运行速度,对其整体线形的一致性进行分析评价.以求为下一阶段平、纵面指标的优化调整提供参考意见.

飞行错觉一直是造成严重飞行事故的主要原因之一,因此采用VC++和ACCESS相结合的方法开发了一套抗飞行错觉模拟训练系统,该系统可以与任何一台飞行模拟器相结合使用,通过网络将需要训练的数据传送给模拟器的飞控等系统软件,由软件驱动硬件,从而使整个模拟器具有一个逼真的环境,飞行员利用模拟器飞行,能体会空中飞行时翻、滚、转等产生的复合错觉,进而找到抗飞行错觉的有效办法,提高飞行员的空间认知能力水平,保障飞行顺利安全.

1.1961年,前苏联人加加林完成了人类第一次进入太空飞行的壮举,加加林也由此成为世界上的第一个进入太空的人,

已有创新平行路径文献用随机数学模型将平行路径简单投射为研发投入——产出的二维线性模式,但该模型对于指导企业解决原始性创新平行路径效应带来的创新网络化、外围化的问题,尚有一定的难度,论文基于Genentech的案例从复杂系统、知识基和实践行为网络三个层面分析了原始性创新平行路径的非线性形成机制:在创新复杂系统中,创新平行路径是客观存在的,越是原始性的创新越能引发更多的创新平行路径;新的知识组合形成技术平台改良或者替代原有技术平台从而形成了原始创新的平行路径,知识基越复杂形成的原始性创新平行路径越多,且平行路径效应越明显;新的技术平台结合不同的市场概念形成了原始性创新的平行路径,市场需求越复杂,形成的原始性创新平行路径越多,且平行路径效应越明显;知识基越复杂,实践网络嵌入方式越复杂,从而形成越多的原始性创新平行路径,且对企业而言平行路径效应越明显.