Physical simulation for low-energy astrobiology environmental scenarios

Speculations about the extent of life of independent origin and the potential for sustaining Earth-based life in subsurface environments on both Europa and Mars are of current and relevant interest. Theoretical modeling based on chemical energetics has demonstrated potential options for viable biochemical metabolism (metabolic pathways) in these types of environments. Also, similar environments on Earth show microbial activity. However, actual physical simulation testing of specific environments is required to confidently determine the interplay of various physical and chemical parameters on the viability of relevant metabolic pathways. This testing is required to determine the potential to sustain life in these environments on a specific scenario by scenario basis. This study examines the justification, design, and fabrication of, as well as the culture selection and screening for, a psychrophilic/halophilic/anaerobic digester. This digester is specifically designed to conform to physical testing needs of research relating to potential extent physical environments on Europa and other planetary bodies in the Solar System. The study is a long-term effort and is currently in an early phase, with only screening-level data at this time. Full study results will likely take an additional 2 years. However, researchers in electromagnetic biosignature and in situ instrument development should be aware of the study at this time, as they are invited to participate in planning for future applications of the digester facility.     

Biogenesis and early life on Earth and Europa: favored by an alkaline ocean?

Recent discoveries about Europa--the probable existence of a sizeable ocean below its ice crust; the detection of hydrated sodium carbonates, among other salts; and the calculation of a net loss of sodium from the subsurface--suggest the existence of an alkaline ocean. Alkaline oceans (nicknamed "soda oceans" in analogy to terrestrial soda lakes) have been hypothesized also for early Earth and Mars on the basis of mass balance considerations involving total amounts of acids available for weathering and the composition of the early crust. Such an environment could be favorable to biogenesis since it may have provided for very low Ca2+ concentrations mandatory for the biochemical function of proteins. A rapid loss of CO2 from Europa's atmosphere may have led to freezing oceans. Alkaline brine bubbles embedded in ice in freezing and impact-thawing oceans could have provided a suitable environment for protocell formation and the large number of trials needed for biogenesis. Understanding these processes could be central to assessing the probability of life on Europa.     

Lessons learned from the Space Flyer Unit (SFU) mission

The Space Flyer Unit (SFU) system and mission chronology are briefly introduced. Lessons learned from the SFU mission are categorized as programmatic and engineering lessons. In the programmatic category are dealt with both international and domestic collaborations. As for the engineering lessons safety design, orbital operation, in-flight anomaly, and post flight analyses are the major topics reviewed.     

The face inversion effect in microgravity: is gravity used as a spatial reference for complex object recognition?

Complex objects are better recognized under a specific orientation. When presented upside down, a face, even very familiar, is recognized with greater difficulty than when presented upright ("Inversion effect"). Up to now it was not possible to decide whether the direction provided by gravity or the one provided by the retina and the body constitutes the spatial reference involved in this "Inversion effect". Three cosmonautes learned photographed faces on the ground and had to recognize them both on ground and on flight. Other photographed faces were learned in flight and where presented for recognition on flight. Results show that the Inversion effect is still present on flight for faces that have been learned on ground as well as for those learned on flight. Persistence of the inversion effect in 0-G shows that gravity is not involved as a spatial reference in recognition of faces. Learning and recognition performances of faces learned in flight were significantly lower than performances for faces learned on ground. A possible role of gravity in configural processing, but not in the Inversion effect, is suggested.     

容错式飞机自动除冰系统

 提出一种高可靠性节能型飞机自动除冰系统,采用节能型电分离式除冰方法,并配有最优能量控制策略,使除冰系统所需的除冰能量大大降低；用容错式系统结构,使整个自动除冰系统的可靠性大大增加。实验结果表明系统可靠性高,并且节能效果显著。     

污水处理自控系统及运行信息化剖析--结合南昌市朝阳污水处理厂进行实例研究

本文在成功的实例基础上介绍了污水处理工艺及其流程自动化系统，剖析了尚存的问题，提出了改进的建议。     

陶瓷盖板结构的应力分析

主要根据拉、压不同模量弹性力学理论,采用空间轴对称体有限元法,对多脉冲发动机的陶瓷盖板结构进行了应力分析。根据发动机的工作特点,在应力分析中考虑了动力响应的问题。为了得到符合工作要求的较为理想的陶瓷盖板结构形式,研究了盖板形状、尺寸大小、支承条件对应力分布的影响。     

基于疏水功能表面的飞机防覆冰机理研究进展

如何规避飞机结冰产生的飞行安全隐患一直是航空领域的重要问题。近年来,疏水材料表面被动防覆冰概念被提出并快速发展起来。首先介绍了在液滴冲击阶段防止表面结冰的机理及方法,系统综述了包括减少水滴与表面接触时间以及减少冰核形成时间的研究方案。又进一步介绍了液滴结冰后的防覆冰机理,综述了通过优化疏水表面性能及微纳结构形貌减小冰黏附力的研究进展。最后对疏水表面防覆冰的发展趋势进行了展望。     

MSK和OKQPSK体制的实验评价

实验室的试验测量指出,当通道具有同比特率带宽近于相等的带宽和典型的有关相位延迟特性时,MSK 与 OKQPSK 调制方式有近乎相等误差率性能.为了在比较不同调制方式的性能时消除硬件质量不同引起的差异,设计与制造了高质量 MSK 与 OKQPSK 发射机和通用模型接收机。因此,调制方式的选择应主要考虑复杂性、对设备组合的敏感度和差分编码合适性,而不是误差率。     

高码率可编程帧同步器

印度的第一颗遥感卫星在1988年3月17日从苏联航天站发射到904km的极地太阳同步轨道。从卫星发送的数据高码速率如下:在S波段是5.2Mbps,x波段是10.4Mbps,载荷数据格式是常用的8328字格式。在数据处理系统的各研制阶段,为测试数据已研制了一种独特的可编程通用帧同步器和分路部件。它可以工作到50Mbps,处理的帧码组长度达128位,每帧长度为2e~(20)位码。此设备可在前面板设置允许误码和码位滑动。本文描述了专为IRS飞行器研制的高码率帧同步器的设计和工作过程。简介指标,系统结构同步方法,码位滑动及测试情况,表明该同步器已获得广泛应用。本设备将大大改善系统的工作性能。