国外检漏技术简介

美国宇航工业部门在检漏中,根据不同工作要求,广泛采用各种不同的检测方法与手段,既有灵敏度高的先进设备,也有灵敏度较低的常规设备,总的原则是:经济、实用、易     

新型汽车燃料M15

我国已研制出一种新型汽车燃料M15,它含85％汽油,15％酒精与溶剂,掘估计,全国     

高技术与航天工艺及其发展战略

包括航天技术在内的高技术以一般技术为基础,同时又对一般技术起着推动、促进作用。工艺技术在大多数高技术领域中占有重要地位。航天工艺是航天高技术中不可缺少的关键环节,是生产航天产品的手段和保证条件。应根据我国国情与航天高技术的特点,制订航天工艺的正确发展方针,集中资金,突出重点,合理使用人力、物力、积极采用以计算机为核心的CAD、CAM、CIM、FMS等先进技术。加强超前性的新工艺研究,缩短研制周期,尽快形成生产能力。加快技术改造,新兴工艺与常规工艺同时并举。充分挖潜,在自力更生的基础上引进国外先进技术、设备。     

Identification of morphological biosignatures in Martian analogue field specimens using in situ planetary instrumentation

We have investigated how morphological biosignatures (i.e., features related to life) might be identified with an array of viable instruments within the framework of robotic planetary surface operations at Mars. This is the first time such an integrated lab-based study has been conducted that incorporates space-qualified instrumentation designed for combined in situ imaging, analysis, and geotechnics (sampling). Specimens were selected on the basis of feature morphology, scale, and analogy to Mars rocks. Two types of morphological criteria were considered: potential signatures of extinct life (fossilized microbial filaments) and of extant life (crypto-chasmoendolithic microorganisms). The materials originated from a variety of topical martian analogue localities on Earth, including impact craters, high-latitude deserts, and hydrothermal deposits. Our in situ payload included a stereo camera, microscope, M?ssbauer spectrometer, and sampling device (all space-qualified units from Beagle 2), and an array of commercial instruments, including a multi-spectral imager, an X-ray spectrometer (calibrated to the Beagle 2 instrument), a micro-Raman spectrometer, and a bespoke (custom-designed) X-ray diffractometer. All experiments were conducted within the engineering constraints of in situ operations to generate realistic data and address the practical challenges of measurement. Our results demonstrate the importance of an integrated approach for this type of work. Each technique made a proportionate contribution to the overall effectiveness of our "pseudopayload" for biogenic assessment of samples yet highlighted a number of limitations of current space instrument technology for in situ astrobiology.     

氢与先进的航天材料

本文简要评述与讨论了普通的、以氢为燃料的高超音速航天器用的特殊结构材料氢脆现象,论证了氢与材料的特殊矛盾,提出了缓解矛盾的方法。     

信息

焊接性能优良的耐腐蚀合金Ni-Cr-Mo-CuNi-Cr-Mo-Cu合金(C-2000)以优良的焊接性能与耐腐蚀性能而日益广泛用于化工、环境污染控制等领域。为测定焊接性能及耐腐蚀性能,对其焊件进行了多种试验。通过变拘束裂纹试验,证明其具有与其它焊接性能优良的Ni-Cr-Mo基合金C-22与C-276相同的抗凝固裂纹性能。通过机械(2T与1.5T横向拉伸)试验,证明其焊缝金属具有良好的延伸性,可以满足母材金属的最小抗拉强度要求。通过腐蚀试验表明,在盐酸、氢氯酸与稀硫酸环境中,C-2000合金的腐蚀率低于C-22与C-276合金,在ASTM G28A溶液中,其耐腐蚀性能与C-…     

焊缝的无损检测技术

概述了外观检查、射线检测、磁粉检测、液体渗透检测与噪声检测五种常用的焊缝无损检测技术，分析、比较了每种方法的特点和优缺点。     

延长水管寿命的新方法

一种延长水管寿命的新方法已在民主德国应用于管道检修工作中。水管清洗后,将一双层纺织软管插进去,在双层软管间充气,再在软管外壁与水管内壁间灌进砂浆,经72小时凝     

Iron-scytonemin complexes: DFT calculations on new UV protectants for terrestrial cyanobacteria and astrobiological implications

Cyanobacterial colonies produce the radiation-protectant biomolecule scytonemin as part of their response strategy for survival in environmentally stressed conditions in hot and cold deserts. These colonies frequently use sandstone rocks as host matrices for subsurface colonization, which is accompanied by a zone of depletion of iron and transportation of iron compounds to the mineral surface. It is suggested that an iron-scytonemin complex could feature in this survival strategy and facilitate the movement of iron through the rock. Calculations were carried out on several hypothetical iron-scytonemin complexes to evaluate the most stable structure energetically and examine the effect of the complexation of the biomolecule upon the electronic absorption characteristics of the radiation-protectant species. The implications for extraterrestrial planetary detection and analytical monitoring of an iron-scytonemin complex are assessed.     

用陶瓷合金制作先进刀具

陶瓷合金是由陶瓷与低熔点金属结合剂组成。碳化钨具有良好的耐磨性，但切削钢材时易受化学腐蚀而产生月牙洼。碳化钛有良好的搞月牙洼性能，但耐磨性与弹性模数很低，可