Excavation of artificial caverns inside asteroids by leveraging rotational self-energy

Future space ventures will likely require exploitation of near-Earth asteroid resources. Moreover, it can be envisaged that asteroids may host habitats in their interiors. In fact, a cavern inside an asteroid would be a natural radiation shield against cosmic radiation and may also serve as a confined environment for storage of mined material such as water ice or other processed volatiles such as propellants. To this end, this paper proposes to leverage the asteroid rotational self-energy to remove material from the asteroid interiors and create a spherical cavern, by means of the orbital siphon concept. The siphon is a chain of tether-connected payload masses (the asteroid material), which exploits the rotation of the asteroid for the delivery of mass from the asteroid to escape. Under certain conditions the siphon can be initiated to ensure self-sustained flow of mass from the asteroid to escape. A net orbital siphon effect is generated by connecting new payloads at the bottom of the chain while releasing the upper payloads. Key parameters are discussed, such as the required siphon dimension and the maximum size of the internal cavity that can be excavated, as a function of the asteroid rotational period. Moreover, assuming elastic material behaviour, a closed-form expression for the stress tensor is found and a failure criterion is used to identify regions in the asteroid interiors subjected to the larger stresses. It is shown that the conditions for failure are relaxed as the radius of the internal void increases.     

A survey of safety separation management and collision avoidance approaches of civil UAS operating in integration national airspace system

Recent years have witnessed a booming of the industry of civil Unmanned Aircraft System (UAS). As an emerging industry, the UAS industry has been attracting great attention from governments of all countries and the aviation industry. UAS are highly digitalized, informationized, and intelligent; therefore, their integration into the national airspace system has become an important trend in the development of civil aviation. However, the complexity of UAS operation poses great challenges to the traditional aviation regulatory system and technical means. How to prevent collisions between UASs and between UAS and manned aircraft to achieve safe and efficient operation in the integrated operating airspace has become a common challenge for industry and academia around the world. In recent years, the international community has carried out a great amount of work and experiments in the air traffic management of UAS and some of the key technologies. This paper attempts to make a review of the UAS separation management and key technologies in collision avoidance in the integrated airspace, mainly focusing on the current situation of UAS Traffic Management (UTM), safety separation standards, detection system, collision risk prediction, collision avoidance, safety risk assessment, etc., as well as an analysis of the bottlenecks that the current researches encountered and their development trends, so as to provide some insights and references for further research in this regard. Finally, this paper makes a further summary of some of the research highlights and challenges.     

太阳能飞机循环飞行的高度剖面能量策略

为满足设定的太阳能飞机多日连续飞行条件，依据飞行过程中当前时刻的飞行高度、光伏输出功率、动力电池组余量等系统状态参数，研究如何分配动力电池组充放电和电推进系统输入等功率。所用策略立足于实时功率平衡，充分利用正午前后的光伏峰值功率用于飞机爬升及充电，在午后下滑过程中利用全部光伏输出，以最大化利用光伏资源；在光伏有效输出不足时则以一定的维持功率下滑，使能量的综合损失最小。方法能够提高以预定夜间飞行高度连续多日续航的成功率，提升飞行高度、纬度、季节范围或搭载能力，或者拓展这几种飞行条件的组合域，优化太阳能飞机的适用性。     

一种基于虚拟页地址映射的NAND Flash管理算法

本文提出了一种基于虚拟页地址映射的NAND Flash管理算法.该算法通过定义坏块表、对应表等结构，以及设计的坏块替换策略和虚拟页地址到实际物理页地址的转换算法，实现上层软件采用虚拟地址对NAND Flash的无坏块连续页地址访问.该算法是一种高效的地址映射算法，能高效地对数据进行索引，占用SRAM空间较少，使系统达到高性能，并使得闪存使用的更加稳定持久.     

FDI飞机舵面损伤故障全局检测的非线性数学模型

阐述了飞机在单舵面损伤故障下 ,建立故障状态下的数学模型 ,以及同样输入条件下飞机正常运动时的数学模型 ,得到飞机在相同飞行条件下损伤时的气动系数和无损伤正常时的气动系数 ,最终得到气动系数的残差。这将为以后飞机过载残差和角加速度残差奠定基础。论文中结合一定的算例给予证实推论的正确性。     

Ту-154М变稳飞机空中飞行模拟试验评述

依据Ту－１５４М变稳飞机的特点，主要进行了不同操纵器、不同控制律和不同显示画面的飞行试验研究。特别是通过中央杆和侧杆、电传系统不同控制律飞行品质特性之间、两种先进控制方案及不同显示方式的比较，不仅掌握了这方面的试飞技术和评定技术，还亲身体验到变稳飞机在发展仿真技术，新机预研及提高试飞员试飞技术和评定技术等方面的巨大作用。     

以培养适用型人才为宗旨建立新型的校外学习中心管理体系

校外学习中心是远程教学和远程学习的活动基地。校外学习中心必须能适应市场经济形势需求,以培养适用型人才为宗旨,不断完善自身机制,实行规范化管理,不断提高教学管理工作水平,建立起新型的管理体系。     

工程陶瓷的加工技术

主要介绍了国内外工程陶瓷特种和常规加工技术的开发及应用近况。     

工业工程在重新规划和改进钣金车间生产现场中的应用

通过分析对比，详细介绍了南飞公司应用工业工程重新规划和改进钣金车间生产现场的作法，以及所取得的技术经济效果。     

浅谈高校后勤服务中的安全管理

随着高校后勤社会化改革的不断发展，高校后勤在市场经济的大潮中不断完善、不断发展，与此同时，高校后勤又面临着进一步深化改革、建立新型服务关系和体制机构以及如何加强安全管理的新形势。如何去适应新的形势的要求，如何提高安全管理的水平，就成了摆在我们面前首先要解决的问题，着重分析了高校后勤服务中的安全管理的目的和意义，指出了高校后勤服务活动中常见事故点，分析了安全事故成因，明确了高校后勤服务中的安全管理的任务，对高校后勤安全管理的发展方向进行了探讨。