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991.
The first and second law of thermodynamics have been used to analyze the performance of an experimental single‐stage heat transformer operating with the water/lithium bromide mixture. Enthalpy coefficients of performance (COP), external coefficients of performance (COPEXT), exergy coefficient of performance (ECOP), exergy destruction or irreversibility in the system and components (I) and the improvement potential (Pot) have been calculated against the gross temperature lift and the main operating temperatures of the system. The results showed that the highest COP, COPEXT and ECOP values are obtained at the highest solution concentrations meanwhile the Pot and the I of the cycle remain almost constant against these parameters. Also it was shown that the COP, COPEXT and ECOP decrease with an increase with the absorber temperature, meanwhile the Pot and the I increase. Moreover, it was observed that in all the cases independently of the operating temperatures of the system, the absorber accounts with most of the half of the total irreversibility in the system. Finally, it was shown that the improvement potential is considerable for the system. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
992.
Various methods of reproduction usual in the graphic arts industry are compared as to their colour-rendering qualities. The methods of reproduction examined differ according to the nature and the number of their intermediate photographic steps. Colour rendering results were obtained by a combination of experimental methods and calculation. The reproduction methods are compared for the case of a perfect grey reproduction, wherein use is made of a definite set of three-colour printing inks. 相似文献
993.
本文介绍了溴化锂吸收式冷水机组能效标准出台的背景,对标准的重要内容进行了解析说明,并对能效标准实施后的趋势进行了分析。 相似文献
994.
Preparation of Fe/Cr doped SiO2 thin film on 304 stainless steel substrate originated from corrosion
《腐蚀工程科学与技术》2013,48(4):453-457
AbstractA Fe/Cr doped SiO2 thin film which can improve the anticorrosion characteristic of materials was prepared on SUS304 stainless steel substrates by a modified hydrothermal method that constitutes a two part preparation process. The corrosion of stainless steel and the dissolution of silica from Na–Ca glass are simultaneously stimulated by an aqueous lithium bromide solution, and then a Fe/Cr doped SiO2 thin film is coated onto the substrate. The Fe/Cr doped SiO2 film was characterised by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and electron probe X-ray microanalyser. The results showed that the corrosion products and the silica are combined to form a Fe/Cr doped SiO2 thin film. Furthermore, a chemical bond is formed between the silicon coating and the metal that improves the compactness and the adhesive property of the film. The anticorrosion characteristics of the film were measured by the methods of weight loss and electrochemical potentiodynamic polarisation, indicating that the Fe/Cr doped SiO2 thin film can improve the anticorrosion performance of stainless steels effectively. 相似文献
995.
As a noble metal, Iridium finds many applications in the industry. Electrodeposited iridium, as a thin coating, provides a cheaper method of using the metal wherever possible. Iridium and platinum-iridium alloy are used in industrial water electrolysis as anodes because of their low oxygen overpotential. Of all the baths available for electrodepositing iridium, the bromide electrolyte appears to be the best. Different methods of preparing the bromide electrolyte are compared: the one prepared using iridium chloride gives improved performance with respect to stability, current efficiency, higher deposit thickness, and appearance of the deposits, besides its cost effectiveness. 相似文献
996.
为回收焦炉荒煤气部分余热,利用超低温热水型溴化锂制冷技术回收初冷器高温段循环水的余热,夏季制冷工况,利用高温段循环水的余热替代蒸汽或煤气制冷;冬季制热工况,回收中温段循环水余热增加采暖供热面积。该技术应用后,机组运行稳定,实现了夏季焦炉煤气的自给式制冷、采暖季进一步回收中温段余热节约蒸汽的目的,年综合效益445万元。 相似文献
997.
实验以环戊酮与苄胺为起始原料,经亲核加成、乙酰化、Vilsmeier反应关环合成了第四代抗生素头孢匹罗的重要中间体2-氯-6,7-二氢-5 H-环戊并[b]吡啶,经3步反应制备了2-氯-6,7-二氢-5 H-环戊并[b]吡啶。合成中间产物N-亚环戊基苄胺的较佳条件为:反应温度为117~121℃,n(苄胺)∶n(环戊酮)=1∶1.02,回流反应时间为40min;合成中间产物N-环戊烯基-N-苄基乙酰胺的较佳条件为:加料温度0~5℃,反应温度25℃,n(苄胺)∶n(乙酸酐)=1∶1.1,反应时间14h;合成2-氯-6,7-二氢-5 H-环戊并[b]吡啶的条件为:三氯氧磷加料温度0~5℃,回流反应时间15h,水解温度为40~45℃。三步反应的总收率为45.9%,产品结构经1 H NMR和LC-MS确证。 相似文献
998.
以仲丁醇铝(aluminum tri-sec-butoxide,ATSB)和硼酸为原料,采用阳离子表面活性剂(cetyltrimethyl ammonium bromide,CTAB)辅助溶胶–凝胶法于120℃形成白色干凝胶,再进行焙烧得到硼酸铝纳米棒。采用X射线衍射仪、扫描电子显微镜、透射电子显微镜、X射线能量色散谱仪和Fourier变换红外光谱仪对产物结构和形貌进行表征。结果表明:750℃焙烧产物为具有单晶结构的Al4B2O9纳米棒,,其形貌及直径、长度受ATSB和硼酸摩尔比影响;当ATSB与H3BO3摩尔比为1:2时,Al4B2O9纳米棒直径约为15nm,长度为200~300nm。1200℃焙烧的产物为Al18B4O33纳米棒,其直径为200~500nm,长度约为3μm。对硼酸铝纳米棒的形成机理进行了初步探讨。 相似文献
999.
1000.