Bacterial cellulose may provide the microbial-life biosignature in the rock records

Bacterial cellulose (BC) is a matrix for a biofilm formation, which is critical for survival and persistence of microbes in harsh environments. BC could play a significant role in the formation of microbial mats in pristine ecosystems on Earth. The prime objective of this study was to measure to what extent spectral and other characteristics of BC were changed under the performance of BC interaction with the earthly rock – anorthosite – via microorganisms. The spectral analyses (Fourier Transform Infrared FT-IR, spectroscopy, and atomic absorption spectroscopy) showed unprecedented accumulation of chemical elements in the BC-based biofilm. The absorption capacity of IR by BC was shielded a little by mineral crust formed by microorganisms on the BC-based biofilm surface, especially clearly seen in the range of 1200–900 cm⁻¹ in FT-IR spectra. Confocal scanning laser microscopy analysis revealed that elements bioleached from anorthosite created surface coats on the BC nanofibril web. At the same time, the vibrational spectra bands showed the presence of the characteristic region of anomeric carbons (960–730 cm⁻¹), wherein a band at 897 cm⁻¹ confirmed the presence of β-1, 4-linkages, which may serve as the cellulose fingerprint region. Results show that BC may be a biosignature for search signs of living organisms in rock records.     

航空发动机叶片丢失问题研究综述

对近年来航空发动机叶片丢失问题的研究进展进行了综述.简述了叶片丢失过程相关的力学问题,重点探讨了叶片丢失激励下转子和整机结构系统的瞬态动力特性以及持续生存能力方面的力学机理、数值仿真和试验研究成果,包括叶片丢失过程中的载荷及力学行为、整机动力学建模和求解技术、整机和机理性的试验研究等.研究表明:对于恶劣载荷环境下复杂结构系统,需要以整机系统为研究对象并考虑载荷时效特征,通过结构和动力学安全性设计策略提升结构完整性和可靠性.      

Biological assessment of Ariane 5 fairing

United Nations Space Treaties [10 and 11] require the preservation of planets and of Earth from contamination. All nations part to these Treaties shall take measures to prevent forward and backward contamination during missions exploring our solar system. As observer for the United Nations Committee on Peaceful Uses of Outer Space, the COSPAR (Committee of Space Research) defines and handles the applicable policy and proposes recommendations to Space Agencies [COSPAR Planetary Protection Panel, Planetary Protection Policy accepted by the COSPAR Council and Bureau, 20 October 2002, amended 24 March 2005. http://www.cosparhq.org/scistr/PPPolicy.htm.]. The goal is to protect celestial bodies from terrestrial biological contamination as well as to protect the Earth environment from an eventual biohazard which may be carried by extraterrestrial samples or by space systems returning to Earth. According to the applicable specifications, including in our case the French requirements [CNES, System Safety. Planetary Protection Requirements. Normative referential CNES RNC-CNES-R-14, CNES Toulouse, ed. 4, 04 October 2002.], the prevention of forward contamination is accomplished by reducing the bioburden on space hardware to acceptable, prescribed levels, including in some instances system sterilization, assembling and integrating the appropriate spacecraft systems in cleanrooms of appropriate biological cleanliness, avoiding or controlling any recontamination risk, and limiting the probability impact of space systems. In order to prepare for future exploration missions [Debus, A., Planetary protection: organization requirements and needs for future planetary exploration missions, ESA conference publication SP-543, pp 103–114, 2003.], and in particular for missions to Mars requiring to control the spacecraft bioburden, a test program has been developed to evaluate the biological contamination under the fairing of the Ariane 5 launcher.     

加速寿命试验的损伤减寿模型

针对加速寿命试验提出了损伤减寿模型，并在产品寿命服从指数分布场合给出了参数的点估计。     

RANDOMIZATION METHOD OF DETERMINISTIC EQUATION FOR PROBABILITY FRACTURE MECHANICS

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基于日地月方位信息的近地轨道卫星自主导航

研究了用日地月方位信息进行卫星自主导航的方法。给出一种最小二乘导航算法。用 Gorddard空间飞行中心发布的我国实践 5号卫星的轨道数据 ,在对地定向三轴稳定的姿态运行模式下 ,模拟出了日、地、月在卫星本体坐标系中的方位测量数据。数字仿真实验结果表明 ,在地球敏感器噪声 0 .10°( 3σ) ,日、月敏感器噪声 0 .0 3°( 3σ)情况下 ,一天之内的导航径向误差在 - 30 0 m～ 2 0 0 m波动 ,相对地心的方位误差不超过 0 .0 4 1°     

远程空空导弹攻防成功概率研究

攻防成功概率是衡量远程空空导弹武器系统作战效能的关键性指标。在研究被动/主动双模导引头远程空空导弹末制导截获概率模型和载机生存概率模型的基础上,建立了攻防成功概率的计算模型,并以F-16战斗机为打击目标进行了验证,进而根据算例结果分析了诸因素对攻防成功概率的影响,为远程空空导弹的作战效能评估提供了有益的参考。     

Bioaugmentation in growing plants for lunar bases

Microorganisms may be a key element in a precursory scenario of growing pioneer plants for extraterrestrial exploration. They can be used for plant inoculation to leach nutritional elements from regolith, to alleviate lunar stressors, as well as to decompose both lunar rocks and the plant straw in order to form a protosoil. Bioleaching capacities of both French marigold (Tagetes patula L.) and the associated bacteria in contact with a lunar rock simulant (terrestrial anorthosite) were examined using the model plant-bacteria microcosms under controlled conditions. Marigold accumulated K, Na, Fe, Zn, Ni, and Cr at higher concentrations in anorthosite compared to the podzol soil. Plants inoculated with the consortium of well-defined species of bacteria accumulated higher levels of K, Mg, and Mn, but lower levels of Ni, Cr, Zn, Na, Ca, Fe, which exist at higher levels in anorthosite. Bacteria also affected the Са/Mg and Fe/Mn ratios in the biomass of marigold grown on anorthosite. Despite their growth retardation, the inoculated plants had 15% higher weight on anorthosite than noninoculated plants. The data suggest that the bacteria supplied basic macro-and microelements to the model plant.     

基于混合细菌觅食算法的多无人机任务分配研究

多无人机协同任务分配问题是多无人机协同控制的关键.本文首先深入分析多无人机任务分配问题的特点,建立了扩展的混合整数线性规划(MILP)任务分配模型.其次,通过分析细菌觅食优化算法和粒子群优化算法的优缺点,提出一种具有较强全局搜索能力且收敛速度快的混合细菌觅食优化算法.最后将该算法应用于多无人机协同任务分配中并进行了仿真...     

Introduction to Japanese exploration study to the moon

The Japan Aerospace Exploration Agency (JAXA) views the lunar lander SELENE-2 as the successor to the SELENE mission. In this presentation, the mission objectives of SELENE-2 are shown together with the present design status of the spacecraft. JAXA launched the Kaguya (SELENE) lunar orbiter in September 2007, and the spacecraft observed the Moon and a couple of small satellites using 15 instruments. As the next step in lunar exploration, the lunar lander SELENE-2 is being considered. SELENE-2 will land on the lunar surface and perform in-situ scientific observations, environmental investigations, and research for future lunar utilization including human activity. At the same time, it will demonstrate key technologies for lunar and planetary exploration such as precise and safe landing, surface mobility, and overnight survival. The lander will carry laser altimeters, image sensors, and landing radars for precise and safe landing. Landing legs and a precisely controlled propulsion system will also be developed. A rover is being designed to be able to travel over a wide area and observe featured terrain using scientific instruments. Since some of the instruments require long-term observation on the lunar surface, technology for night survival over more than 2 weeks needs to be considered. The SELENE-2 technologies are expected to be one of the stepping stones towards future Japanese human activities on the moon and to expand the possibilities for deep space science.