Planetary resources and astroecology. Planetary microcosm models of asteroid and meteorite interiors: electrolyte solutions and microbial growth--implications for space populations and panspermia

Planetary microcosms were constructed using extracts from meteorites that simulate solutions in the pores of carbonaceous chondrites. The microcosms were found to support the growth of complex algal and microbial populations. Such astroecology experiments demonstrate how a diverse ecosystem could exist in fluids within asteroids, and in meteorites that land on aqueous planets. The microcosm solutions were obtained by extracting nutrient electrolytes under natural conditions from powders of the Allende (CV3) and Murchison (CM2) meteorites at low (0.02 g/ml) and high (10.0 g/ml) solid/solution ratios. The latter solutions contain > 3 mol/L electrolytes and about 10 g/L organics, that simulate natural fluids in asteroids during aqueous alteration and in the pores of meteorites, which can help prebiotic synthesis and the survival of early microorganisms. These solutions and wet solids were in fact found to support complex self-sustaining microbial communities with populations of 4 x 10(5) algae and 6 x 10(6) bacteria and fungi for long periods (> 8 months). The results show that planetary microcosms based on meteorites can: assay the fertilities of planetary materials; identify space bioresources; target astrobiology exploration; and model past and future space-based ecosystems. The results show that bioresources in the carbonaceous asteroids can sustain a biomass of 10(18) kg, comprising 10(32) microorganisms and a human population of 10(14). The results also suggest that protoplanetary nebulae can support and disperse microorganisms and can be therefore effective environments for natural and directed panspermia.     

钢筋砼梁的修补与增强

钢筋砼梁由于某种原因使得局部或全部结构受到损坏，为恢复和提高梁的承载能力，曾纺式用了几种修补和增强的方法。环氧树脂稀浆用于封闭梁的裂缝，用加大断面和增加钢筋数量来提高梁的抗弯能力。经试验用水泥稀浆和环氧树脂砂浆作为粘结材料是有效的，达到了预期的目的。     

钢纤维增强的砼剪力墙

近几年钢纤维混凝在建筑领域的应用研究不断深化。本文介绍了用钢纤维混凝土取代梁、柱中的部分箍筋，从而提高了剪刀墙和联系梁结构的整体性。并在相同延性时比普通砼有更高的极限强度。     

The Soviet-Russian space suits a historical overview of the 1960's

The development of protective suits for space use started with the Vostok-suit SK-1, first used by Yu. Gagarin on April 12, 1961, and then used on all subsequent Vostok-flights. The technical background for the design of these suits was the work on full pressure protective suits for military pilots and stratospheric flights in the 1930's through 50's. The Soviet-Russian space programme contains a large number of 'firsts', and one of the most well known is the first EVA by Leonov in 1965. This event is also the starting point for a long series of space suit development for Extravehicular Activities over the last 35 years. The next step to come was the transfer in void space of crew members between the two spacecraft Soyuz 4 and 5 in 1969. As has later become known this was an essential element in the planned Soviet lunar exploration programme, which in itself required a new space suit. After the termination of the lunar programme in 1972, the space suit development concentrated on suits applicable to zero-gravity work around the manned space stations Salyut 6, Salyut 7 and MIR. These suits have become known as the ORLAN-family of suits, and an advanced version of this suit (ORLAN-M) will be used on the International Space Station together with the American EMU. This paper covers the space suit development in the Soviet Union in the 1960's and the experience used from the pre-space era.     

斜拉桥钢索的抗蚀保护

预应力砼结构技术的发展,推动了斜拉桥的广泛应用,且具有结构形式经济的虎性。拉索和锚具的高强度和抗疲劳特性以及抗蚀保护成为设计工程师设计的关键。该文着重介绍了近几年 来美国斜拉钢索的防抗蚀方面的新方法、新材料。     

砼剪力墙的合理设计法

我国对钢筋砼剪力墙的计算，一般根据《砼结构设计规范》（BGJ10－89）和《钢筋砼高层建筑结构设计与施工规程》（JGJ3－91）中的公式进行计算，工作量相当浩繁。澳大利亚Curtin大学土木工程系教授B．Viuaya Rangan提出了一种简化计算法，本文仅对此作一简单的介绍。     

硅灰在塞浦路斯的应用实例

硅灰是硅金属生产中的一种付产品，具有能提高砼强度，减少砼的碱－硅反应（ＡＳＲ）等性能，可掺入高强砼中用于相应的建筑工程中，同时具有提高硅的抗硫酸盐的性能，由于塞浦路斯海岸线的土层中硫酸盐的含量高，因而硅灰在塞浦路斯获得广泛的应用，该文着重介绍了硅灰在塞浦路斯的应用实例。