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81.
MFI type inorganic carrier was used in two different cationic forms, hydrogen and calcium respectively. MFI-supported molybdenum and rhenium catalysts were prepared. The activities of the catalysts were compared for the aromatization reaction of methane. Higher activity values were attained with the catalysts supported on HZSM-5. Aromatics were also observed with the catalysts supported on CaZSM-5, despite their deficiency in acid sites. Highly dispersed rhenium is expected to be formed with the use of the inorganic carrier in calcium form. On the other hand, lower reaction rates were observed with rhenium supported on CaZSM-5, in spite of the improved dispersion of the active rhenium species on this catalyst. This was interpreted in terms of the critical role of the acid sites in the conversion of methane to aromatics, compared to the improved dispersion of the active metal.  相似文献   
82.
合成丁酸异戊酯的新方法   总被引:3,自引:0,他引:3  
采用超强酸代替浓硫酸作催化剂,对丁酸异戊酯合成反应进行了研究,讨论了影响收率的多种因素,在最佳条件下,酯化反应时间短,催化剂可以重复使用,丁酸异戊酯收率达到98%。  相似文献   
83.
84.
铜氨废水处理与废铜液回收   总被引:6,自引:0,他引:6  
简述某电子厂生产电路板过程中产生的镀铜废液,废水回收处理方法,介绍应用高质量浓度含铜废液制取工业硫酸铜与海绵铜的工艺方法和流程,铜氨废水的处理要用破络添加混凝剂沉淀后可达标排放,对调试,运行中一般故障的排除进行了论述。  相似文献   
85.
Game design elements are often implemented in persuasive systems aimed to promote physical activity, a process called “gamification.” Gamification is believed to motivate users to become more active, and is commonly implemented in commercial products. However, relatively few studies rigorously evaluated the effectiveness of gamification, and they yielded contradicting findings. We set out to evaluate the effectiveness of virtual rewards and social comparison—two game elements prevalent in persuasive systems. We developed a research prototype, called “StepByStep,” aimed to promote routine walking. We created different versions of StepByStep, implemented as an application on Android-based mobile devices, and compared their effectiveness in two field studies. Study 1 showed that a quantified version of the application—offering continuous measurement of walking time, a daily goal, and real-time feedback on progress toward this goal—facilitated reflection on activity and significantly increased walking time over baseline level. Study 2 showed that gamified versions offering virtual rewards and social comparison were only as effective as the quantified version. Thus, we advise designers to facilitate reflection on meaningful aspects of physical activity by developing novel ubiquitous measures. Furthermore, our findings highlight the importance of systematic comparisons between quantified and gamified elements for better understanding their motivational affordances.  相似文献   
86.
Ozonation of purine and pyrimidine bases and of carbohydrates was studies in laboratory experiments. The results showed that nucleobases are much more reactive with molecular ozone in aqueous solution than carbohydrates. Second order rate constants for direct reaction of ozone on purines (adenine and guanine) and on pyrimidines (cytosine, thymine and uracil) ranged from 0.76 × 103 to 6.8 × 103 M-1s-1at 2°C. The difference of reactivity between these solutes may be attributed to their substituents. As far as carbohydrates are concerned, direct reactions of ozone are very slow k03 ? 0.1 – 0.3 M-1s-1 at 20°C, and the results indicated that free radical reactions are predominant in the degradation pathway of carbohydrates by ozone. Some ozonation by-products of monosaccharides (glucose, xylose) and disaccharides (cellobiose) also were identified in this study by means of GC/MS analyses.  相似文献   
87.
Ben 《电脑》2014,(2)
正随着中国市场化的逐步放开和信息化时代的全面到来,中国4S店的整车销售高利润的时代已经一去不复返了!几乎所有的厂商都全面重视售后市场,全面进军美容、装潢和精品等市场领域。装潢项目大部分4S单店采用售车促销赠送方式,虽然其他销售业绩可观,但是随着市场信息透明度的加强,类似隔热膜的利润随年下降。精品项目随着网购井喷  相似文献   
88.
Ben 《电脑》2014,(1):196-197
十年发展,十年沉淀,十年新起点!2013年12月9日,由上海追得贸易发展有限公司主办的"智慧·创新·分享"暨"大师贴膜品牌升级行业发布会"于上海兴荣温德姆五星级酒店隆重召开。时值企业成立十周年,大师贴膜品牌迎来了又一次里程碑式的跨越,追得企业也将迎来更加创新的发展模式。  相似文献   
89.
Rock phosphate fractions were examined for their porous structure by nitrogen adsorption. The pore size distribution and the shape of pores does not seem to depend on the particle size. The specific surface area values present two regions, one above and one below that of the particles with 125 μrn diameter. Particles of a given size were leached with dilute phosphoric acid (1.5 mass% P2O5) at 25°C. It was observed that there is a widening of the initial pores during leaching. The particles collected at the initial period of the reaction are pitted and those collected at the final period are disintegrated.  相似文献   
90.
Ben 《电脑》2014,(6):198-198
正眼下,信息的日益透明化、渠道的日渐扁平化、消费的日趋理性化都给国内窗膜市场提出了新的要求,中美合资羿阳(Unisun)科技趁机而入,带来Sundef山迪品牌,给行业、给消费者带来了源自美国的高性价比高端产品选择。新时代下的消费新需求中国的太阳膜市场拥有近20年的发展历史,期间经历了多次变革。眼下,隔热膜已成为汽车  相似文献   
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