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101.
Monocrystalline 6H-SiC thin films have been epitaxially grown on off-axis 6H-SiC {0001} substrates in the temperature range
of 1623–1873 K via chemical vapor deposition. The growth rate was a strong function of the growth temperature and the reactant
gas concentration. The activation energies for growth were 64 kJ/mole and 55 kJ/mole for the (0001) Si face and the (0001)
C face, respectively. The concentration of growth pits in the films increased as a function of decreasing deposition temperature,
increasing concentration of reactant gases and increasing off-axis orientation. Beta-SiC islands were also observed in the
epilayers when the (SiH4 + C2H4)/H2 ratio was ≥2.5:3000. 相似文献
102.
103.
2,6-二甲基萘生产技术进展 总被引:2,自引:0,他引:2
许杰 《精细石油化工进展》2003,4(2):44-47
概述了国外2,6-二甲基萘生产技术现状,详细介绍了ExxonMobil公司2,6-二甲基萘的工艺路线和日本神户制钢所的提纯方法,指出了实现我国2,6-二甲基萘工业化生产应注意的问题。 相似文献
104.
Floodplain waterbodies are reputed to enhance recruitment of riverine fish populations via provision of spawning and nursery habitat, refuge from floods, and increased availability of planktonic food resources compared with main river channels. Notwithstanding, there have been few parallel studies of fishes and their food resources at both main river and floodplain sites. Thus, this study investigated the 0+ fishes, zooplankton and phytoplankton (chlorophyll a) at four main river and four (man‐made) floodplain sites on the lower River Trent, England, between May 1999 and October 2004 inclusive. All sites shared the same key fish species, and there were no consistent differences in the densities, growth or condition of 0+ fishes from main river and floodplain sites. Similarly, all sites shared the same key zooplankton taxa. However, zooplankton densities, notably of large‐bodied cladocerans, and chlorophyll a concentrations, were significantly higher at floodplain sites than at main river sites. Thus, connection of man‐made waterbodies has the potential to enhance recruitment of riverine fish populations via provision of important spawning and nursery habitat, and superior feeding opportunities for 0+ fishes compared with main river channels. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
105.
106.
107.
Mitsuhiro Fukuta Tadashi Yanagisawa Hiroaki Iwata Kazutaka Tada 《International Journal of Refrigeration》2002,25(7)
This paper discusses the feasibility of a vapor compression/absorption hybrid refrigeration cycle for energy saving and utilization of waste heat. The cycle employs propane as a natural refrigerant and a refrigeration oil as an absorbent. A prototype of the cycle is constructed, in which a compressor and an absorption unit are combined in series. The performance of the cycle is examined both theoretically and experimentally. Although the solubility of the propane with the oil is not enough as a working pair in the absorption unit, the theoretical calculation shows that the hybrid cycle has a potential to achieve a higher performance in comparison with a simple vapor compression cycle by using the waste heat. In the experiment, the prototype cycle is operated successfully and it is found that an improvement of an absorber is necessary to achieve the good performance close to the theoretical one. The application of an AHE (absorber heat exchanger) can reduce the heat input to a generator. Further examinations on some other combinations of refrigerant/refrigeration oil and additives are desirable. 相似文献
108.
S. J. Pearton K. P. Lee M. E. Overberg C. R. Abernathy N. Theodoropoulou A. F. Hebard R. G. Wilson S. N. G. Chu J. M. Zavada 《Journal of Electronic Materials》2002,31(5):336-339
High concentrations (0.1–5 at.%) of Mn or Fe were introduced into the near-surface region (≤2000 Å) of 6H-SiC substrates by direct implantation at ~300°C. After annealing at temperatures up to 1000°C, the structural properties were examined by transmission electron microscopy (TEM) and selected-area diffraction pattern (SADP) analysis. The magnetic properties were examined by SQUID magnetometry. While the Mn-implanted samples were paramagnetic over the entire dose range investigated, the Fe-implanted material displayed a ferromagnetic contribution present at <175 K for the highest dose conditions. No secondary phases were detected, at least not to the sensitivity of TEM or SADP. 相似文献
109.
110.
从催化裂化柴油中分离高纯度2,6-二甲基萘 总被引:3,自引:0,他引:3
以大庆石油化工总厂炼油厂催化柴油为原料 ,通过精馏分离得到二甲基萘 (DMN)窄馏分 (2 5 8~ 2 70℃ ) ,经糠醛溶剂抽提 ,减压蒸馏后 ,在 -10~ -2 5℃冷冻 2~ 5h ,离心分离制得纯度约 80 %的粗 2 ,6 DMN ,再经无水乙醇在 -10~ -2 5℃重结晶 ,得到纯度大于等于 98%的 2 ,6 DMN。 相似文献