光学系统的偏振分析

对于大多数光学系统，一般都假设透射波面具有均匀的振幅（或高斯型振幅）和恒定的偏振态。这是几何光学的不完善假设。文中讨论的方法，适合于分析这种假设不能成立的系统。文中所讨论的偏振分析法包括了偏振光线追迹和偏振像差论。文中还讨论了偏振现象的基本分类定义，并述评了琼斯（Ｊｏｎｅｓ）计算法，以此作为讨论的基础。     

Bubble detector characterization for space radiation

In light of the importance of the neutron contribution to the dose equivalent received by space workers in the near-Earth radiation environment, there is an increasing need for a personal dosimeter that is passive in nature and able to respond to this neutron field in real time. Recent Canadian technology has led to the development of a bubble detector, which is sensitive to neutrons, but insensitive to low linear energy transfer (LET) radiation. By changing the composition of the bubble detector fluid (or “superheat”), the detectors can be fabricated to respond to different types of radiation. This paper describes a preliminary ground-based research effort to better characterize the bubble detectors of different compositions at various charged-particle accelerator facilities, which are capable of simulating the space radiation field.     

中远程巡航导弹突防对抗技术研究

具有精确打击特点的中远程巡航导弹是各国防御 /防空体系重点拦截和摧毁的目标 ,西方强国纷纷加大了在防御巡航导弹方面的投入 ,因此巡航导弹的突防对抗能力成为其能否完成作战使命的关键。从巡航导弹面临的战场环境威胁分析入手 ,指出了巡航导弹可采取的突防对抗技术措施。     

Using Spacelab as a precursor of science operations for the Space Station

For more than 15 years, Spacelab, has provided a laboratory in space for an international array of experiments, facilities, and experimenters. In addition to continuing this important work, Spacelab is now serving as a crucial stepping-stone to the improved science, improved operations, and rapid access to space that will characterize International Space Station. In the Space Station era, science operations will depend primarily on distributed/remote operations that will allow investigators to direct science activities from their universities, facilities, or home bases. Spacelab missions are a crucial part of preparing for these activities, having been used to test, prove, and refine remote operations over several missions. The knowledge gained from preparing these Missions is also playing a crucial role in reducing the time required to put an experiment into orbit, from revolutionizing the processes involved to testing the hardware needed for these more advanced operations. This paper discusses the role of the Spacelab program and the NASA Marshall Space Flight Center- (MSFC-) managed missions in developing and refining remote operations, new hardware and facilities for use on Space Station, and procedures that dramatically reduce preparation time for flight.     

Mineralization of wastes of human vital activity and plants to be used in a Life Support System

Available methods for mineralizing wastes of human activity and inedible biomass of plants used in this country and abroad are divided into two types: dry mineralization at high temperatures up to 1270 K with subsequent partial dissolution of the ash and the other--wet oxidation by acids. In this case mineralization is performed at a temperature of 470-460 K and a pressure of 220-270 atmospheres in pure oxygen with the output of mineral solution and dissoluble sediments in the form of scale. The drawback of the first method is the formation of dioxins, CO, SO2, NO2 and other toxic compounds. The latter method is too sophisticated and is presently confined to bench testing. The here proposed method to mineralize the wastes is in mid-position between the thermal and physical chemical methods. At a temperature of 80-90 degrees C the mixture was exposed to a controlled electromagnetic field at normal atmospheric pressure. The method merits simplicity, reliability, produces no dissoluble sediment or emissions noxious for human and plants. The basic difference from the above said methods is to employ as an oxidizer atomic oxygen, its active forms including OH-radicals with hydrogen peroxide as the source. Hydrogen peroxide can be produced with electric power from water inside the Life Support System (LSS).     

Determination of lethality rate constants and D-values for heat-resistant Bacillus spores ATCC 29669 exposed to dry heat from 125°C to 200°C

Exposing flight hardware to dry heat is a NASA-approved sterilization method for reducing microbial bioburden on spacecraft. The existing NASA specification only allows heating the flight hardware between 104°C and 125°C to reduce the number of viable microbes and bacterial spores. Also, the NASA specifications only allow a four log reduction by dry heat microbial reduction because very heat-resistant spores are presumed to exist in a diverse population (0.1%). The goal of this research was to obtain data at higher temperatures than 125°C for one of the most heat-resistant microorganisms discovered in a spacecraft assembly area. These data support expanding the NASA specifications to temperatures higher than 125°C and relaxing the four log reduction specification. Small stainless steel vessels with spores of the Bacillus strain ATCC 29669 were exposed to constant temperatures between 125°C and 200°C under both dry and ambient room humidity for set time durations. After exposures, the thermal spore exposure vessels were cooled and the remaining spores recovered and plated out. Survivor ratios, lethality rate constants, and D-values were determined at each temperature. The D-values for the spores exposed under dry humidity conditions were always found to be shorter than those under ambient humidity. The temperature dependence of the lethality rate constants was obtained by assuming that they obeyed Arrhenius behavior. The results are compared to those of B. atrophaeus ATCC 9372. In all cases, the D-values of ATCC 29669 are between 20 and 50 times longer than those of B. atrophaeus ATCC 9372.     

Biosignatures from Earth-like planets around M dwarfs

Coupled one-dimensional photochemical-climate calculations have been performed for hypothetical Earth-like planets around M dwarfs. Visible/near-infrared and thermal-infrared synthetic spectra of these planets were generated to determine which biosignature gases might be observed by a future, space-based telescope. Our star sample included two observed active M dwarfs-AD Leo and GJ 643-and three quiescent model stars. The spectral distribution of these stars in the ultraviolet generates a different photochemistry on these planets. As a result, the biogenic gases CH4, N2O, and CH3Cl have substantially longer lifetimes and higher mixing ratios than on Earth, making them potentially observable by space-based telescopes. On the active M-star planets, an ozone layer similar to Earth's was developed that resulted in a spectroscopic signature comparable to the terrestrial one. The simultaneous detection of O2 (or O3) and a reduced gas in a planet's atmosphere has been suggested as strong evidence for life. Planets circling M stars may be good locations to search for such evidence.