波音董事长兼CEO詹姆士·麦克纳尼谈创新

<正> 创新对于詹姆士·麦克纳尼来说是一个非常有兴趣的话题。在接受美国《航空周刊与空间技术》(AwsT)采访的过程中,他明确地阐述了自己对创新定义的理解,解释了创新能力远比技术能力重要得多的原因。 AWST:你认为创新的最主要意义是什么? 麦克纳尼:创新的最大意义在于提高你的用户或者消费者的竞争力。衡量创新的影响力,主要是衡量创新对于客户和经济体的快速成长或者生产力的提高所产生的影响力有多大。实际上,创新越多,成本就会越低。也就是说,创新能够让企业在提高员工工资、增加再投资和提高人们的生活水平方     

Raman spectroscopic analysis of a desert cyanobacterium Nostoc sp. in response to UVB radiation

Cyanobacteria are capable of tolerating environmental extremes. To survive in extreme environments, cyanobacteria have developed the capability to adapt to a variety of stresses. For example, cyanobacteria have adopted a number of strategies with which to survive UV stress, including expression of UV-screening pigments and antioxidant systems. We have previously shown that several antioxidants are significantly expressed in Nostoc sp. by UVB irradiation. We report here that the content of UV-responsive biomarkers such as β-carotene and scytonemin can be easily detected by Fourier transform Raman spectroscopy with use of a small sample size and that the content of β-carotene is dependant on the UVB intensity and exposure time. Our results indicate that Raman spectroscopy may be a helpful tool to analyze UV-protective molecules of cyanobacterium in astrobiological studies without access to large sample sizes and complicated extractions, which are needed by other analytical techniques such as high-performance liquid chromatography and mass spectrometry.     

高压涡轮工作叶片叶型设计研究

针对高压涡轮工作叶片叶栅型面特征,采用可压燃气黏性流2维计算方法对高压涡轮工作叶片叶型进行了气动研究,并通过试验验证了优化设计,得到了叶栅气动设计参数。经与初始叶型对比,优化叶型在各状态下损失特性变化更为平缓,在超临界状态下效率更高,在λ2is=1.20状态下的损失减少了2.8%。该方法缩短了设计时间,并且节省了平面叶栅吹风试验的成本。     

带有补片电极的矩形AT切石英片的厚度切变、厚度扭转和弯曲振动

本文研究了补片《矩形》电极尺寸和质量对镀膜矩形晶体片的振动和能陷的影响。文中采用晶体片振动的Mindlin二维近似方程来保留厚度切变、厚度扭转和弯曲的耦合膜。通过采用位移公式以有限元法获得数值解,此解满足晶体片的边缘静止条件和在晶体片镀膜与非镀膜交界处的应力和位移的连续条件。文內对位置对称的补片电极矩形AT切石英片进行了数值计算,获得了晶体片和电极不同尺寸和不同质量时的谐振频率及其相应的二维振动膜。Mindlin和Lee,Lee和Spencer及Tiersten把计算结果同现有的分析结果做了比较,而Curran和Koneval把计算结果与实验数据进行了比较。所得二维Bechmann数基本上取决于三个参数:电极长度与晶体片厚度之比;电极宽度与晶体片厚度之比;以及电极质量与晶体单位面积质量之比。     

PHYSIOLAB: a new laboratory for the study of the cardio-vascular system

On the basis of the experience gained during the previous french-russian missions on board MIR about the adaptation processes of the cardio-vascular system, a new laboratory has been designed. The objective of this “PHYSIOLAB” is to have a better understanding of the mechanisms underlying the changes in the cardio-vascular system, with a special emphasis on the phenomenon of cardio-vascular deconditioning after landing.

Beyond these scientific objectives, it is also intended to use PHYSIOLAB to help in the medical monitoring on-board MIR, during functional tests such as LBNP.

PHYSIOLAB will be set up in MIR by the French cosmonaut during the next french-russian CASSIOPEE mission in 1996. Its architecture is based on a central unit, which controls the experimental protocols, records the results and provides an interface for transmission to the ground via telemetry. Different specific modules are used for the acquisition of various physiological parameters.

This PHYSIOLAB under development for the CASSIOPEE mission should evolve towards a more ambitious laboratory, whose definition would take into account the results obtained with the first version of PHYSIOLAB. This “second generation” laboratory should be developed in the frame of wide international cooperation.     

Astrobiology through the ages of Mars: the study of terrestrial analogues to understand the habitability of Mars

Mars has undergone three main climatic stages throughout its geological history, beginning with a water-rich epoch, followed by a cold and semi-arid era, and transitioning into present-day arid and very cold desert conditions. These global climatic eras also represent three different stages of planetary habitability: an early, potentially habitable stage when the basic requisites for life as we know it were present (liquid water and energy); an intermediate extreme stage, when liquid solutions became scarce or very challenging for life; and the most recent stage during which conditions on the surface have been largely uninhabitable, except perhaps in some isolated niches. Our understanding of the evolution of Mars is now sufficient to assign specific terrestrial environments to each of these periods. Through the study of Mars terrestrial analogues, we have assessed and constrained the habitability conditions for each of these stages, the geochemistry of the surface, and the likelihood for the preservation of organic and inorganic biosignatures. The study of these analog environments provides important information to better understand past and current mission results as well as to support the design and selection of instruments and the planning for future exploratory missions to Mars.     

Titan and exobiological aspects of the Cassini-Huygens mission

Titan, the largest satellite of Saturn, has a dense N2-CH4 atmosphere rich in organic compounds, both in gas and in aerosol phases. Its surface is probably covered by oceans of liquid methane-ethane mixtures, with many dissolved organics. This quasi planet appears as a natural laboratory to study chemical evolution toward complex organic systems in a planetary environment over a long time scale. With the Cassini-Huygens mission NASA and ESA will jointly send an orbiter (Cassini) around Saturn and a probe (Huygens) in the atmosphere of Titan. This mission, currently planned to be launched in 1996-1997 for a Saturn - Titan arrival in 2004, offers a unique opportunity to study in detail extra-terrestrial organic processes. Consequently, it has important implications in the field of exobiology and the origins of life.