Lunar equatorial regolith temperature profiles were simulated using the half-limited solid heat conduction model. Based on the infrared data measured using the Diviner radiometer on the Lunar Reconnaissance Orbiter la...
详细信息
Lunar equatorial regolith temperature profiles were simulated using the half-limited solid heat conduction model. Based on the infrared data measured using the Diviner radiometer on the Lunar Reconnaissance Orbiter launched by the United Sates in June 2009, three factors influencing temperature profiles were analyzed. The infrared brightness temperature data from Diviner channel 7 were used to retrieve surface temperature. In simulating regolith temperature profiles, the retrieved temperature, rather than temperatures calculated from solar radiance at the lunar surface, were used as the input for surface temperature in solving the heat-conductive equation. The results showed that the bottom-layer temperature at depths of 6 m approached almost 246 K after 10000 iterations. The temperature was different to the temperature of 250 K at the same depth encountered in simulations using solar radiance. Simulations from both methods of surface temperatures over a lunar day gave similar variations. At lunar night, the temperature difference between the two was about 2 K; the main differences occurred when the solar elevation angle was very low when surface temperatures are largely affected by terrain topography. With no certainty in lunar temperature profiles at present, the advantage of the retrieval method using infrared sensor data as input to the boundary conditions in solving the lunar heat conduction equation is that simulations of surface temperature variations are more accurate. This is especially true in areas with large variations in terrain topography, where surface temperatures vary greatly because of shading from the sunlight.
Performance of simultaneous desulfurization and denitration using the solution of NaClO2 and NaClO as new-style complex absorbent was investigated experimentally in self-designed bench scale bubbling reactor. The effe...
详细信息
Performance of simultaneous desulfurization and denitration using the solution of NaClO2 and NaClO as new-style complex absorbent was investigated experimentally in self-designed bench scale bubbling reactor. The effects of main parameters, such as the concentrations of NaClO2 and of NaClO, solution pH and reaction temperature and so on, on removal efficiencies of SO2 and NOx, were examined, then the optimal conditions were established, in which the molar ratio of NaClO to NaClO2 was 1：1, the reaction temperature was 50℃ and the solution pH was 5.5. The removal efficiencies of SO2 and NO under the optimal conditions were 100% and 89.2%, respectively. The mechanism of simultaneous removal based on complex absorbent was proposed by analyzing the removal products and the electrode potentials of related species, namely SO2 and NO are oxi- dized by chlorite anion, hypochlorite, chlorine dioxide and chlorine contained in complex absorbent. In thermodynamic aspect, simultaneous desulfurization and denitration reactions in liquid phase can happen spontaneously and completely, and are all exothermic reactions. It was confirmed by kinetics that for simultaneous desulfurization and denitration, the reaction order and average activation energy of SO2 were 1 and 21.6 kJ·mol^-1, respectively, and those of NO were 1 and 8.2 kJ·mol^-1, respectively.
The inclusion-complex of CD-MCP （β-cyclodextrin （β-CD） including 1-methylcyclopropene （1-MCP）） was prepared and characterized. Basing on programmed-heating procedure and weight-temperature analysis, as well as...
详细信息
The inclusion-complex of CD-MCP （β-cyclodextrin （β-CD） including 1-methylcyclopropene （1-MCP）） was prepared and characterized. Basing on programmed-heating procedure and weight-temperature analysis, as well as the application of Satava-Sestak＇s, Ozawa＇s and Kissinger＇s methods, the mechanism and kinetics of thermal dissociation of this inclusion complex were studied. An additional mass loss is found at 170-180℃. The mechanism of thermal dissociation of CD-MCP is dominated by a one-dimensional random nucleation and subsequent growth process （A2/3）. The activation energy Es and the pre-exponential factor AS for the process are 102.14 kJ/mol and 3.63×10^10s^-1, respectively. This ES value shows that there is no strong chemical intere, ctions between β-CD and 1-MC;P,
Ti-6Al-4V compacts were fabricated by metal injection molding (MIM). Influence of vacuum sintering time on mechanical properties of the sintered compacts at 1260℃were investigated. The experimental results show that ...
详细信息
Ti-6Al-4V compacts were fabricated by metal injection molding (MIM). Influence of vacuum sintering time on mechanical properties of the sintered compacts at 1260℃were investigated. The experimental results show that the compacts sintered at 1 260℃ for 3 hours～6 hours, which was made from hydrogenation-dehydrogenation(HDH) powder(averageparticles size is 45 μm), had a relative density of 95.6%～ 96.7%, ultimate tensile strength (648 MPa～686 MPa) and 0.2% yield strength (526 MPa～615 MPa) but a lower elongation (95%),ultimate tensile strength (800 MPa～848 MPa), 0.2% yield strength (712 MPa～762 MPa) and high elongation (7.4%～9.5%).The mechanical properties of mixed powder specimens were nearly equivalent to the ASTM for the PM compacts.
To isolate seed-expressed sequences, a cDNA library was constructed using wheat ( Triticumaest/vum L) seed tissues at 12 d after pollination. Plasmid DNAs of 10 000 clones randomly picked out fromthe library were prep...
详细信息
To isolate seed-expressed sequences, a cDNA library was constructed using wheat ( Triticumaest/vum L) seed tissues at 12 d after pollination. Plasmid DNAs of 10 000 clones randomly picked out fromthe library were prepared. The preparation of high density filters were made with the Biomek 2000 HDRTsystem, and then hybridized separately with three probes prepared by reverse transcription of RNA ofunpollinated ovary, embryo and endosperm. Based on the hybridization results, 800 clones expressed inembryo and/or endosperm were chosen for further analysis of expressed sequence tags (ESTs). Finally,216 different genes were identified preliminarily. Of them, 24 (11.5%) were considered identical to knownwheat genes, 122 (56%) were identified as putative new plant genes which may be involved in seed storageproteins, biochemical metabolisms, development, and other biological processes of seeds, while 70 (32.5%)sequence identities could not be determined.
维普期刊数据库
同方期刊数据库
暂无评论