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61.
62.
A method has been developed for the preparation of modified silica plates for high performance thin-layer chromatography (HPTLC). Some typical organosilanes were thus allowed to react in situ with the silica of Merck HPTLC-plates. This method was found to be highly reproducible, simple and cheap. Non-polar plates were prepared and compared with commercial plates from Merck, Whatman and Macherey-Nagel. Modification with cyanodecyltrichlorosilane resulted in plates that showed good coverage, efficiency and low residual silica activity. Silica modified with a multifunctional silane has different properties in different organic solvents. It will appear to be non-polar in a polar solvent and vice versa. New advantageous separation systems are thus made feasible by the presence of cyano groups on the plate. The utility of modified thin-layer plates is demonstrated by the separation of some homologues of p-hydroxybenzoic acid esters and of some polycyclic aromatic hydrocarbons. 相似文献
63.
研究了半导体隔片光电化学电池(SC-SEP)中光池溶液的pH、暗池溶液的氧化还原电对以及两池中的暗电极对电池的开路电压、光生电压、短路光电流和光伏安特性的影响。对它们的影响机制进行了初步分析。通过合理选择电池体系,SC-SEP的性能可比单隔室的光电化学电池(PEC)优越。 相似文献
64.
John A. Rogers Zhenan Bao 《Journal of polymer science. Part A, Polymer chemistry》2002,40(20):3327-3334
Plastic electronic materials and high‐resolution printing methods may be important technologies for new classes of consumer electronic devices that are lightweight, mechanically flexible and bendable, and that can cover large areas at low cost. This article summarizes some of our recent work in this area. It focuses on the materials and patterning techniques that we used to produce plastic active‐matrix backplane circuits for a type of paperlike display. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3327–3334, 2002 相似文献
65.
可见光化的半导体光催化剂 总被引:1,自引:0,他引:1
光解水制氢能否实用化取决于太阳光的有效利用率, 研究开发可见光化的光催化剂成为当前光催化剂研究中的重要课题.本文介绍了利用 光解水制氢的反应机理,综述了近年来半导体光催化剂在利用可见光方面的研究进展,重点描述了这些光催化剂的结构,并对该领域今后的研究方向进行了展望. 相似文献
66.
电沉积AuInSe2半导体薄膜上的电化学振荡现象 总被引:1,自引:0,他引:1
研究了电沉积制得的AuInSe2半导体薄膜上过氧化氢阴极还原过程中产生的电化学振荡行为,对影响该振荡行为的一些因素如半导体薄膜的后处理、溶液组成、传质、光照、化学浸渍作用等进行了分析,同时采用外界周期性光照和外接小幅度正弦波电位来调节振荡频率,为金铟硒半导体薄膜发展成为光电传感器件提供了一定的理论与实践基础. 相似文献
67.
Bodnarchuk M. I. Kovalenko M. V. Stroyuk A. L. Kuchmii S. Ya. 《Theoretical and Experimental Chemistry》2004,40(5):287-292
The photochemical behavior of solutions containing a mixture of CdS and CdTe nanoparticles under pulsed irradiation conditions was investigated. It was shown that electron transfer from the CdS particles to the CdTe nanoparticles occurs during the photoexcitation of such systems. The effectiveness of the process is increased with increase in the size of the CdTe nanoparticles. Such behavior is due to decrease in the potential of the CdTe conduction band with increase in the size of the nanoparticles as a result of the appearance of quantum-dimensional effects. 相似文献
68.
向列相液晶被广泛应用于液晶显示中,但是由于杂质的存在,会导致液晶的驱动电压变大,增加能耗。 为了降低阈值电压和饱和电压,通常向液晶中添加纳米颗粒来提高电光性能。 本文利用水热法制备了表面粗糙和光滑的两种立方体Fe2O3纳米颗粒,其形貌均匀,尺寸约550 nm。 将二者分别掺杂到向列相液晶E7中,结果表明,粗糙立方体Fe2O3/E7复合体系具有比光滑立方体Fe2O3/E7复合体系和向列相液晶E7更优的电光性能,且在掺杂质量分数为0.4%时,其电光性能达到最优,阈值电压和饱和电压分别降低9.9%和11.6%,对比度增大80%,响应时间降低至6.0 ms。 这归因于粗糙立方体Fe2O3具有足够的表面积和表面所带电荷更多,所以会更易吸附体系中的杂质离子和减弱杂质离子的屏蔽作用,从而提高了电光性能。 相似文献
69.
Masoumeh Hasani Mojtaba Shamsipur 《Journal of inclusion phenomena and macrocyclic chemistry》1993,16(2):123-137
The formation of ammonium complexes with several crown ethers and cryptands in nitrobenzene, acetonitrile and dimethylformamide solutions was investigated by conductometry at 25°C. Stability constants of the resulting 1:1 complexes sere determined from the molar conductance-mole ratio data and found to vary in the order DC18C6>18C6>DB30C10>DB21C7>DB24C8>DB18C6>15C5>B15C5>12C4, in the case of crown complexes, and in the order C222>C221>C211>C22>C21 for the ammonium cryptates. The stabilities of the complexes varied inversely with the Gutmann donicity of the solvents. Influences of the number of members in the macrocycle, nature of the substituents in the polyether ring, cavity size and dimensionality, conformations of the free and complexed ligands and number of N+–H bonds available for hydrogen bonding are discussed. 相似文献
70.
A. Lainez M. M. Rodrigo Emmerich Wilhelm J. -P. E. Grolier 《Journal of solution chemistry》1992,21(1):49-65
Excess molar volumes V
E
and excess molar heat capacities C
P
/E
at constant pressure have been obtained, as a function of mole fraction x1, for several binary liquid mixtures belonging either to series I: pyridine+n-alkane (ClH2l+2), with l=7, 10, 14, 16, or series II: piperidine+n-alkane, with l=7, 8, 10, 12, 14. The instruments used were a vibrating-tube densimeter and a Picker flow microcalorimeter, respectively. V
E
of pyridine+n-heptane shows a S-shaped composition dependence with a small negative part in the region rich in pyridine (x1>0.90). All the other systems show positive V
E
only. The excess volumes increase with increasing chain length l of the n-alkane. The excess molar heat capacities of the mixtures belonging to series II are all negative, except for a small positive part for piperidine+n-heptane in the region rich in piperidine (x1>0.87). The C
P
/E
at the respective minima, C
P
/E
(x1,min
), become more negative with increasing l, and the x1,min
values range from about 0.26 (l=7) to 0.39 (l=14). Most interestingly, mixtures of series I exhibit curves of C
P
/E
against x1 with two minima and one maximum, the so-called W-shape curves.Dedicated to Professor A. Néckel on the occasion of his 65th birthday. Communicated in part at the XVIIèmes Journées de Calorimétrie, d'Analyse Thermique et de Thermodynamique Chimique, Ferrara, Italy, 27–30 October, 1986. 相似文献