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991.
活性氧化铝载体的研制 总被引:6,自引:0,他引:6
氧化铝是催化剂常用的载体。本文讨论了氢氧化铝凝胶制备工艺参数对产物氢氧化铝物性的影响。 相似文献
992.
993.
为获得持久抗菌的功能丝绸材料,采用硝酸、磷酸、亚硝酸钠体系将原料壳聚糖的C6位伯羟基选择性氧化为羧基制得水溶性氧化壳聚糖(OCS),使OCS的羧基与脱胶蚕丝织物(SFF)的氨基反应,得到氧化壳聚糖改性蚕丝织物(OCSMSF)。借助核磁共振仪、扫描电子显微镜、红外光谱仪、X射线衍射仪等手段表征了OCS与OCSMSF的化学结构,测试了OCSMSF的力学、吸湿、抗菌等性能。结果表明:酰胺反应已将氧化壳聚糖分子化学键合在SFF中,OCS改性蚕丝纤维的结晶度降低;在优化反应参数条件下,OCS接枝蚕丝织物的质量增加率达到9.17%,OCSMSF的强力略有减小,而吸湿性提高42.92%,OCSMSF对测试细菌的抑菌率大于94%,且抗菌耐洗涤性好,同时OCSMSF对仙人掌黄酮提取物有良好的缓释效果。 相似文献
994.
995.
Marc Jungo Daniel Erni Werner Baechtold 《International Journal of Numerical Modelling》2003,16(2):143-159
We propose a new set of equations describing a cylindrical vertical cavity surface emitting laser (VCSEL) cavity under CW operation, based on the rate equations including lateral carrier diffusion. The only numerical step in the calculation consists in finding the roots of a polynomial expression. This model enables a quasi‐instantaneous calculation of the laser's light‐current characteristic, including such effects as spatial hole burning, current spreading, inhomogeneous optical intensity distribution, and diffusion losses. An analysis of the VCSELs threshold current and differential quantum efficiency is proposed, which illustrates the interplay between injected current profile and diffusion coefficient. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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997.
本文介绍了现役航空母舰、巡洋舰、驱逐舰和护卫舰主动力装置的装舰情况。统计分析了最近三十年来上述战舰各种发动机的装舰使用情况,指出了各型战舰主动力装置的发展趋势 相似文献
998.
《International Journal of Hydrogen Energy》2020,45(56):32089-32097
Liquid organic hydrogen carriers (LOHCs) represent a promising approach for hydrogen storage due to their favorable properties including stability and compatibility with the existing infrastructure. However, fossil-based LOHC molecules are not green or sustainable. Here we examined the possibility of using norbelladine and trisphaeridine, two representative structures of Amaryllidaceae alkaloids, as the LOHCs from the sustainable and renewable sources of natural products. Our first principles thermodynamics calculations reveal low reversibility for the reaction of norbelladine to/from perhydro-norbelladine because of the existence of stabler isomers of perhydro-norbelladine. On the other hand, trisphaeridine is found promising due to its high hydrogen storage capacity (~5.9 wt%) and favorable energetics. Dehydrogenation of perhydro-trisphaeridine has an average standard enthalpy change of ~54 kJ/mol-H2, similar to that of perhydro-N-ethylcarbazole, a typical LOHC known for its low dehydrogenation enthalpy. This work is a first exploration of Amaryllidaceae alkaloids for hydrogen storage and the results demonstrate, more generally, the potential of bio-based molecules as a new sustainable resource for future large-scale hydrogen storage. 相似文献
999.
《International Journal of Hydrogen Energy》2020,45(58):32884-32898
Shanghai is one of the fastest growing regions of hydrogen energy in China. This paper researched feasible hydrogen sources in both internal and external Shanghai. This study comes up 9 hydrogen production methods and 6 transportation routes, ultimately forms 12 hydrogen supply solutions according to local conditions. The total cost in each solution is estimated including processes of hydrogen production, treatments, storage and transportation based on different transport distance. The results indicate that hydrogen supply cost is above 50 CNY/kgH2 for external hydrogen sources after long-distance transportation to Shanghai, such as hydrogen production from coal in Inner Mongolia and from renewables in Hebei. The total cost of on-site hydrogen production from natural gas can be controlled under 40 CNY/kgH2. When the price of wind power reduces to 0.5 CNY/kWh, hydrogen production from offshore wind power cooperating with hydrogen pipeline network has the greatest development potential for Shanghai hydrogen supply. 相似文献
1000.
《能源学会志》2020,93(4):1261-1270
The chemical looping gasification (CLG) of rice husk was conducted in a fixed bed reactor to analyze the effects of the ratio of oxygen carrier to rice husk (O/C), temperature, residence time and preparation methods of Fe-based oxygen carriers. The yield of gas, H2/CO, lower heating value of syngas (LHV), conversion efficiency and performance parameters were analyzed to obtain CLG reaction characterization and optimal reaction conditions. Results showed that when O/C increased from 0.5 to 3.0, the gas production, H2/CO, CO2 yield and carbon conversion efficiency gradually increased, while the yield of H2, CO and CH4 and LHV gradually decreased. At the same time, a highest gasification efficiency was obtained when O/C was 1.5. As increasing temperature, the gas production, CO yield, carbon conversion efficiency and gasification efficiency gradually increased, while the yield of H2, CH4 and CO2, H2/CO and LHV gradually decreased. Sintering and agglomeration was obvious when the temperature was higher than 850 °C. When the reaction time increased from 10 min to 60 min, the gas production, CO yield, carbon conversion efficiency and gasification efficiency gradually increased, but the yield of H2, H2/CO and LHV decreased, among which 30 min was the best reaction residence time. In addition, coprecipitation was the best preparation method among several preparation methods of oxygen carrier. Finally, O/C of 1.5, 800 °C, 30 min and coprecipitation preparation method of oxygen carrier were the optimal parameters to obtain a gasification efficiency of 26.88%, H2 content of 35.64%, syngas content of 56.40%, H2/CO ratio of 1.72 and LHV of 12.25 MJ/Nm3. 相似文献