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991.
微波场中A型分子筛及分子筛膜合成的研究 总被引:8,自引:0,他引:8
Effects of aging time and alkalinity as well as cation concentration(Na+) on the synthesis of A type zeolite and zeolite membrane were investigated in this paper. The results showed that aging time for synthesis of A type zeolite and zeolite membrane had remarkable influence and alkalinity could accelerate the formation of zeolite but was disadvantage to zeolite membrane synthesis. Cation concentration(Na+) also couldn′t accelerate the synthesis of zeolite and zeolite membrane but it was probable an important factor to accelerate crystal growth .Moreover, more compact zeolite membranes could be synthesized by this method while the thickness of membrane was thinner than that of convention. Zeolites and zeolite membranes were characterized by XRD, TEM as well as IR characterization techniques. 相似文献
992.
提出了一种简明的理论分析方法,求出了三分子反应A+2X 3X在一维介质上的动力学行为的解析解,并成功地解决了该反应动力学行为对初始条件的依赖性问题。还通过数值模拟证实了提出的理论方法的正确性。 相似文献
993.
The intelligent controlled drug delivery systems (DDS) are a series of the preparations including microcapsules or nanocapsules composed of intelligent polymers and medication. The properties of preparations can change with the external stimuli, such as pH value, temperature,chemical substance, light, electricity and magnetism etc. According to this properties, the DDS can be intelligently controlled. This paper has reviemed research on syntheses and applications of intelligent controlled DDS of polymer carriers.Drug delivery system with pH stimuliThe volume of polymer hydrogel can change with the pH value of external environment. The sensitive polymer hydrogels to pH are often as carriers. The polymer hydrogel carrying medicine is especially suitable for taking orally. In order to protect medicine from losing activation, we enwrapped medicine into polymer hydrogel with acidic group. In the acidic environment of stomach,the volume of polymer hydrogel contracts because of the hydrogen bond. The medicine in the polymer hydrogel cannot disperse out. When it goes to the intestine of basic environment, the hydrogen bond will be broken, and the medicine can release.Drug delivery system with temperatureTemperature sensitive polymer hydrogel can change its volume with changing of environmental temperature. This kind of polymer hydrogel can be also used as a carrier of medicine. At a low temperature, the polymer chains form hydrogen bond with water to swell to let medicine disperse out from the hydrogel. On the other hand, the hydrogen bond will be broken and polymer chain will lose water to contract with temperature's increasing. And the medicine will not disperse out. For example,the poly(N-isopropylacrylamide)(PNIPAAm) is the hydrogel that is swelled at lower temperature and contracted at higher temperature. PNIPAAm has the lower critical solution temperature(LCST).We can adjust its LCST to control PNIPAAm hydrogel's swelling or contraction to let medicine release or not.Drug delivery system with other stimuliThe polymer carrier drug delivery system can be intelligently controlled with the stimuli of pH value and temperature. In addition, there are still some other stimuli for DDS. For example, DDS with light; DDS with electricity(or electric field); DDS with magnetism(magnetic field); DDS with chemical substance; etc. The characteristic of intelligent polymer carrier is based on P.J.Flory's gel-swelling theory. Intelligent polymer carrier DDS will be widely used in biological and medical fields. 相似文献
994.
WANG Fei LIU YongSheng WAN XiangJian ZHOU JiaoYan & CHEN YongSheng Key Laboratory for Functional Polymer Materials Centre for Nanoscale Science Technology 《中国科学B辑(英文版)》2011,(4)
One polythiophene derivative PT3T and two low band gap copolymers,PBTT-T3T and PBTT,with different ratios of 5,6-dini-trobenzothiadiazole as the acceptor unit in the polymer backbone have been synthesized by Pd-catalyzed Stille-coupling polymerizations.Thermal stability,X-ray diffraction analyses,UV-vis absorption spectra,photoluminescence spectra and electrochemical properties of the copolymers were investigated.The band gap estimated from UV-vis-NIR spectra of the copolymers films varied from 1.39 to 1.94... 相似文献
995.
The local maxima of water density in the space near the single-helical of Konjac glucomannan as well as the dominant conformation of the system was studied by molecular dyna-mics under the water environment. The results indicate that the hydration shell,potential energy,and its hydrogen bond network with water bridges of the left-handed single-helix conformation was favored compared to those of right-handed single-helix conformation. This work suggests that the left-handed single-helix conformation was the dominant conformation of KGM in the water environment. 相似文献
996.
997.
Some excellent catalysts for ODE reaction,such as K-Sr-Bi-O-Cl[1], LiCl/sulfated-zirconia[2], which have high conversion of ethane and selectivity to ethylene, have been reported recently. But the relatively high reaction temperatures up to 620℃ and/or very low GHSV have been used over above catalyst systems. So the research aimed at searching for new catalysts with good performances at low temperatures appears to be desirable. 相似文献
998.
超微NaY分子筛的合成(Ⅰ)──添加轻稀土离子的影响 总被引:11,自引:0,他引:11
导向剂的陈化时间和反应胶的晶化温度可以影响NaY分子筛的晶化行为.随导向剂陈化时间的增加,NaY分子筛的晶化速度加快,晶粒尺寸减小;随晶化温度的升高,NaY分子筛的晶化速度加快,但晶粒尺寸增加.而向合成体系中添加轻稀土离子(Ln3+)对NaY分子筛的晶化行为影响更为明显.与未添加稀土离子时相比较,在一定的稀土离子添加量范围内[n(Ln3+)/n(Al3+)<0.2],NaY分子筛的晶化速度明显加快而晶粒尺寸显著减小,同时所合成出的NaY分子筛的n(SiO2)/n(Al2O3)比也有较大的提高.添加稀土离子使合成体系中形成异晶晶种的Ln(OH)3微晶,从而进一步引发NaY分子筛的成核. 相似文献
999.
提出了一种基于COM-Express Nano工控板现IP调度台的方法。给出了系统硬件和软件结构,描述了软硬件各个模块的功能。该设计方案以COM-Express Nano工控板为软件和硬件平台,在此基础上实现IP视频和音频调度设备,具有容易实现可扩展性强等特点。 相似文献
1000.
充分考虑复杂网络中只有部分状态变量可测量的特点,提出了辨识复杂网络拓扑结构的新方法.针对复杂网络中存在部分不可测状态变量的问题,在系统具有多输出的情况下,提出了一种利用降维观测器辨识网络拓扑的方法;进一步实现了仅利用输出变量就能辨识网络拓扑.根据Lyapunov稳定性理论,推导出了设计观测器的条件和拓扑辨识方法.与现有基于观测器的复杂网络辨识方法相比,该方法更加简单实用.最后利用该方法对复杂网络的拓扑结构进行辨识仿真,效果良好. 相似文献