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61.
K. Durga Prasad S.V.S. Murty 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
A Wireless Sensor Network for in situ probing of lunar water/ice is proposed. The mission scenario in single and multi-tier architectures for probing water in a permanently shadowed region of the Moon and different scenarios of exploration are discussed. The ideas presented in the paper are a positive assertion of feasibility for the sensor node hardware, given current levels of technological advancements. 相似文献
62.
A. Buch R. Sternberg C. Szopa C. Freissinet C. Garnier El J. Bekri C. Rodier R. Navarro-González F. Raulin M. Cabane M. Stambouli D.P. Glavin P.R. Mahaffy 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
In the frame of the 2009 Mars Science Laboratory (MSL) mission a new sample preparation system (SPS) compatible with gas chromatography–mass spectrometry (GC–MS) has been developed for the in situ analysis of complex organic molecules in the Martian soil. The goal is to detect, if they exist, some of the key compounds that play an important role in life on Earth including carboxylic acids, amino acids and nucleobases. 相似文献
63.
采用热重-差热分析联用(TG-DTA)、差示扫描量热(DSC)、加压热重(PTG)等热分析方法,研究了镁基水反应金属燃料热分解反应的基本特性及其变化规律。研究发现,燃料热分解过程中先后发生AP分解反应、HTPB分解反应,氩气中不发生Mg的氧化反应;添加催化剂、减小AP粒度、增大氧化剂与粘合剂比例、增大细Mg粉含量等,可以降低燃料中AP的分解温度T,减小表观活化能Ea,增大反应速率常数k;减小AP粒度、增大氧化剂与粘合剂比例可以降低燃料中HTPB的分解温度,减小表观活化能Ea,增大反应速率常数k;随着压强增大,AP与HTPB分解失重速率增大、AP失重百分数增大、燃料热分解凝聚相产物质量百分数减少,压强对AP分解影响较大,对HTPB分解影响较小。 相似文献
64.
俞赞琪 《西安航空技术高等专科学校学报》2005,23(5):55-56,59
通过对处理制泥废水及烧结废水工艺、设备、措施及综合利用进行了详细的描述,对拟用新措施将污水二次处理预期达到饮用及绿化水标准提出了建设性的设想,采用现代计算机FLASH软件将生产工艺制作成动画演示,强化了工厂管理体系. 相似文献
65.
66.
Bruce Fegley Jr. 《Space Science Reviews》2000,92(1-2):177-200
Thermochemical equilibrium calculations predict gas phase, gas-grain, and solid phase reactions as a function of pressure
and temperature in the solar nebula. However, chemical reactions proceed at different rates, which generally decrease exponentially
with decreasing temperature. At sufficiently low temperatures (which vary depending on the specific reaction) there may not
have been enough time for the predicted equilibrium chemistry to have taken place before the local environment cooled significantly
or before the gaseous solar nebula was dispersed. As a consequence, some of the high temperature chemistry established in
sufficiently hot regions of the solar nebula may be quenched or frozen in without the production of predicted low temperature
phases. Experimental studies and theoretical models of three exemplary low temperature reactions, the formation of troilite
(FeS), magnetite (Fe3O4), and hydrous silicates, have been done to quantify these ideas. A comparison of the chemical reaction rates with the estimated
nebular lifetime of 0.1-10 million years indicates that troilite formation proceeded to completion in the solar nebula. Magnetite
formation was much slower and only thin magnetite rims could have formed on metal grains. Hydrous silicate formation is predicted
to be even slower, and hydrous silicates in meteorites and interplanetary dust particles probably formed later on the parent
bodies of these objects, instead of in the solar nebula.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
67.
In order to improve the deposition rate and microstructure of pyrocarbon, nickel was introduced by electroplating on carbon fibers and used as a catalyst during the deposition of pyrocarbon at 1000 C using methane as a precursor gas. The distribution of nickel catalyst and the microstructure of pyrocarbon were characterized by scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), X-ray diffraction(XRD), and Raman micro-spectrometry. Results show that nano-sized nickel particles could be well distributed on carbon fibers and the pyrocarbon deposited catalytically had a smaller d002 value and a higher graphitization degree compared with that without catalyst. In addition, the deposition rate of pyrocarbon in each hour was measured.The deposition rate of pyrocarbon in the first hour was more than 10 times when carbon cloth substrates were doped with nickel catalysts as compared to the pure carbon cloths. The pyrocarbon gained by rapid deposition may include two parts, which are generation directly on the nickel catalyst and formation with the carbon nanofibers as crystal nucleus. 相似文献
68.
Caroline Andrade Enner Alcântara Nariane Bernardo Milton Kampel 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2019,63(7):2175-2188
Monitoring chlorophyll-a (Chl-a) concentrations in inland waters is crucial for water quality management, since Chl-a is a proxy for phytoplankton biomass and, thus, for ecological health of a water environment. Chl-a concentration can be retrieved through the inherent optical properties (IOPs) of a water system, which, in turn, can be remotely sensed obtained. Quasi-analytical algorithm (QAA), originally developed for ocean waters, can also retrieve IOPs for inland waters after re-parameterizations. This study is aimed at assessing the performance of sixteen schemes composed by QAA original and re-parameterized versions followed by models that use absorption coefficients as inputs for estimating Chl-a concentration in Ibitinga reservoir, located at Tietê River cascading system, São Paulo State, Brazil. It was verified that only QAAV5 based schemes were able to obtain reasonable estimates for image data and that by four models tested presented similar and acceptable results for QAAV5 outputs. The best model were applied to a Ocean and Land Colour Instrument (OLCI) image. Light absorption in the reservoir showed to be dominated by colored dissolved organic matter (CDOM), and wide spatial and temporal variability of optical and water quality properties was observed. 相似文献
69.
机载蒸发循环系统动态仿真 总被引:1,自引:0,他引:1
从部件的数学模型出发,根据闭环系统各部件的耦合关系,建立了机载蒸发循环系统的动态数学模型。对充注R142b的机载蒸发循环系统进行了动态仿真,仿真数据与试验数据基本吻合,仿真方法可靠,可以作为机载蒸发循环系统优化及系统控制的依据。 相似文献
70.
FINITE DIFFERENCE MODEL FOR SIMULATION OF DENSIFYING CARBON-CARBON COMPOSITES BY CHEMICAL VAPOR INFILTRATIONP ROCESSES 总被引:1,自引:0,他引:1
NomenclaturesA0—coeficientoftheArheniusequationC(n)—hydrocarbonconcentrationinunit(n)(mol/cm3)C0—hydrocarbonconcentrationatex... 相似文献