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141.
142.
Effect of Enzyme Modification of Corn Grits on their Properties as an Adsorbent in a Skarstrom Pressure Swing Cycle Dryer 总被引:1,自引:0,他引:1
Corn grits have been tested as a desiccant in a pressure swing adsorption (PSA) system to produce dry air. Two sizes of unmodified corn grits were tested in the PSA system: 2.16 and 0.978 mm in diameter, which dried moist air to dew points of –42°C and –69°C, respectively. A modification technology has been developed for the corn grits that gives an increase in the operational adsorptive capacity in a pressure swing adsorption system, so that they remove as much moisture from air as molecular sieves at the same conditions. After modification, 2.16 mm corn grits dry moist air to a –56°C dew point and the 0.978 mm corn grits dry air to a –80°C dew point. The modification process creates surface modifications on the corn grits apparently making more adsorption sites easily available. The modification procedure increases the specific surface area of the grits and possibly decreases the crystallinity, which would make more hydroxyl groups available for adsorption of water. Possible applications of using corn grits in the pressure swing adsorption system include industrial gas dryers, sorptive cooling air conditioners, and recycling equipment for industrial solvents. 相似文献
143.
Elena Laukhina Vladislava Tkacheva Salavat Khasanov Leokadia Zorina Jordi Gómez-Segura Angel Pérez del Pino Jaume Veciana Vladimir Laukhin Concepció Rovira 《Chemphyschem》2006,7(4):920-923
Temperature has great impact on the structure and size of the linked crystallites of the conducting topmost layer formed at the surface of a polycarbonate film via the reaction BEDT-TTF+IBr [BEDT-TTF=bis(ethylenedithio)tetrathiafulvalene]. We show that fine temperature control permits formation of a semiconducting topmost layer of alpha'-(BEDT-TTF)(2)(I(x)Br(1-x))(3) crystallites with either micro- or nanometre size, a result that opens a route to miniaturized conducting plastic materials. 相似文献
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148.
以钛氧有机物为前驱物制备具有高光催化活性的纳米二氧化钛晶体 总被引:9,自引:0,他引:9
纳米二氧化钛的制备方法及前驱物的差别影响其光催化活性.将20ml钛酸丁酯及30ml乙酐在密闭容器中与50ml环己烷混合,在70~85℃反应30min,生成微细的非晶钛氧有机物;经FT-IR和TGA分析,该物质被确认为计量式是TiOOOCCH3)2和TiO(OC4H9)(OOCCH3)的混合体.该钛氧有机物前驱物经焙烧后得到具有高光催化活性的纳米二氧化钛晶体.表征结果表明,钛氧有机物在焙烧过程中,其表面的吸附物及键合有机基团在400℃以前发生脱附和氧化分解;在389~405℃间形成锐钛矿型晶体,在600℃出现金红石晶型;600℃焙烧3h所得样品的比表面积为86m2/g,其二次粒子呈200~300nm条形体,孔隙大于20nm;单分散粒子为球形单晶,粒径为22nm;表面物理吸附水量为1.21%,加热至800℃时失重1.48%,粉体稳定纯净.光催化实验结果表明,以钛氧有机物为前驱物制备的纳米二氧化钛晶体具有高的光催化活性,光降解丁基罗丹明溶液的反应速率常数约为溶胶-凝胶法制备的催化剂样品的4倍.表面氧空缺和一定量的表面羟基可能是粉体具有高光催化活性的重要因素. 相似文献
149.
Sumio Aisawa 《Journal of solid state chemistry》2003,174(2):342-348
The intercalation of non-ionized guest pentoses (ribose and 2-deoxyribose) into the Mg-Al and Zn-Al layered double hydroxides (LDHs) was carried out at 298 K by the calcination-rehydration reaction using the Mg-Al and Zn-Al oxide precursors calcined at 773 K. The resulting solid products reconstructed the LDH structure with incorporating pentoses, and the maximum amount of ribose intercalated by the Mg-Al oxide precursor was approximately 20 times that by the Zn-Al oxide precursor. The ribose/Mg-Al LDH was observed to have the expanded LDH structure with a broad (003) spacing of 0.85 nm. As the thickness of the LDH hydroxide basal layer is 0.48 nm, the interlayer distance of the ribose/Mg-Al LDH is 0.37 nm. This value corresponds to molecular size of ribose in thickness (0.36 nm), supporting that ribose is horizontally oriented in the interlayer space of LDH. The maximum amount of ribose intercalated by the Mg-Al oxide precursor was approximately 5 times that of 2-deoxyribose. Ribose is substituted only by the hydroxyl group at C-2 position for 2-deoxyribose. Therefore, the number of hydroxyl group of sugar is essentially important for the intercalation of sugar molecule into the LDH, suggesting that the intercalation behavior of sugar for the LDH was greatly influenced by hydrogen bond between hydroxyl group of the intercalated pentose and the LDH hydroxide basal layers. 相似文献
150.
Composite materials were processed by casting a mixture of aqueous suspensions of latex and microfibrils. These microfibrils, or whiskers, are extracted from a sea animal and are monocrystals of cellulose, with an aspect ratio around 100 and an average diameter of 20 nm. It has been found that the mechanical properties (shear modulus) are increased by more than two orders of magnitude in the rubbery state of the polymeric matrix, when the whisker content was 6% (w/w). This very large effect is discussed on the basis of different types of mechanical models and it is concluded that these whiskers form a rigid network, probably linked by hydrogen bonds. The formation of this network is assumed to be governed by a percolation mechanism. 相似文献