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排序方式: 共有1613条查询结果,搜索用时 171 毫秒
61.
A novel alignment method for control of high pretilt angle in nematic liquid crystals (NLC), using a solvent dipping effect on various alignment layers, was successfully investigated. The pretilt angle of a NLC is increased by dipping before rubbing treatment on three kinds of rubbed polyimide (PI) surfaces. The pretilt generated by the dipping after rubbing a PI surface with a short side chain is high compared with a PI surface with a long side chain. The pretilt generated by dipping before rubbing homeotropic layer of a positive type NLC (δε > 0) is lower than that of the negative type NLC (δε < 0). The generated NLC pretilt angle is attributed to the perpendicular component of the permittivity epsilon of the NLC. 相似文献
62.
A new photoalignment material, copoly(4-methacryloyloxychalcone-cholesteryl methacrylate) (copoly(M4Ch-ChMA)), was synthesized and the electro-optical characteristics for the photoaligned vertically aligned (VA) liquid crystal display (LCD) were studied. Excellent voltagetransmittance characteristics were achieved for the photoaligned VA-LCD with 1 min polarized UV exposure at an oblique direction of 30° on the copoly(M4Ch-ChMA) surfaces. The response time of the VA-LCD was about 39 ms, and increased with increasing UV exposure time. We suggest that the proportion of photodimerized chalcone group increased with increasing UV exposure time, contributing to a higher response time. 相似文献
63.
Suk Soon Choi Hyun Min Lee Jeong Hyub Ha Dong Gyun Kang Chang Sup Kim Jeong Hyun Seo Hyung Joon Cha 《Applied biochemistry and biotechnology》2013,171(5):1170-1177
During wastewater treatment, phosphate removal is an important and challenging process; thus, diverse technologies, including those derived from biological means, have been devised for efficient phosphate removal. Although conventional biological methods are effective in decreasing wastewater phosphate levels to ~1 mg/L, long periods of microbial adaptation are required for effective phosphate removal, and the removal efficiency of these methods is relatively poor at lower phosphate concentrations. In the present work, we constructed a recombinant Escherichia coli with periplasmic-expressed phosphate-binding protein (PBP) and investigated its biological removal ability for low phosphate levels. We found that the PBP-expressing recombinant E. coli cells showed efficient (> 94 %) removal of phosphate at low concentrations (0.2–1.0 mg/L) in a treated cell mass-dependent manner. Collectively, we propose that our PBP-expressing recombinant whole-cell system could be successfully used during wastewater treatment for the biological removal of low concentrations of phosphate. 相似文献
64.
All possible optically active regioisomers of myo‐inositol mono‐ and bisphosphates were synthesized using inositol derivatives suitably protected with various protecting groups (IRns) as key intermediates. A series of procedures including Novozym 435 catalyzed enzymatic resolution of (3aR,4S,7S,7aR)‐rel‐3a,4,7,7a‐tetrahydro‐2,2‐dimethyl‐1,3‐benzodioxole‐4,7‐diol diacetate, several protection and deprotection reactions, and acyl migration afforded two enantiomeric pairs of IR5 and six enantiomeric pairs of IR4. Phosphorylation of these key intermediates by the phosphitylation and oxidation procedure gave the target products after removal of the protecting groups. 相似文献
65.
Hyun Ook Seo Dae Han Kim Kwang-Dae Kim Eun Ji Park Chae Won Sim Young Dok Kim 《Adsorption》2013,19(6):1181-1187
Adsorption and desorption of toluene on bare and TiO2-coated silica with a mean pore size of 15 nm under dry and humid conditions were studied using toluene breakthrough curves and temperature programmed desorption (TPD) of toluene and CO2. Two TiO2/silica samples (either partially or fully covered with TiO2) were prepared with 50 and 200 cycles of TiO2 atomic layer deposition (ALD), respectively. The capacity of silica to adsorb toluene improved significantly with TiO2-thin film coating under dry conditions. However, toluene desorption from the surface due to displacement by water was more pronounced for TiO2-coated samples than bare samples under humid conditions. In TPD experiments, silica with a thinner TiO2 film (50-ALD cycled) had the highest reactivity for toluene oxidation to CO2 both in the absence and presence of water. Toluene adsorption and oxidation reactivity of silica can be controlled by modifying the silica surface with small amount of TiO2 using ALD. 相似文献
66.
67.
We synthesized a fluorescent adenosine derivative, rApy, as a probe to study RNA structural transitions, in particular the intermolecular G-quadruplex formation. rApy was incorporated into the dangling positions of guanine-rich oligonucleotides, which under physiological conditions undergo π-stacking on top of each other exhibiting a strong emission signal in their G-quadruplex conformation, but not in their single-stranded state. 相似文献
68.
Hyun Ook Seo Myung‐Geun Jeong Kwang‐Dae Kim Dae Han Kim Young Dok Kim Dong Chan Lim 《Surface and interface analysis : SIA》2014,46(8):544-549
Degradation behaviors of poly(3‐hexylthiophene‐2,5‐diyl) (P3HT) layers on NiO in the presence of H2O at ambient pressure and dark conditions were studied using X‐ray photoelectron spectroscopy (XPS). Upon H2O exposure at 120 °C, partial oxidation of P3HT together with molecular water incorporation, but with the maintained local ring‐structure, were deduced by XPS. Valence band spectra of XPS evidenced that the partial oxidation of P3HT local structure could alter π‐conjugation systems of P3HT layers, forming additional electronic states close to its original highest occupied molecular orbital. For comparison, P3HT surface was also exposed to O2, and no change in the S 2p and C 1s spectra was found by O2 exposure at 120 °C, implying that H2O plays a major role at the initial stage of P3HT oxidation. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
69.
Electrophoresis 2014, 35, 1504–1508. DOI: 10.1002/elps.201400001 Combination of DNA biobarcode assay with micro‐capillary electrophoretic analysis on a chip allows us to perform breast and colorectal cancer cell detection with high sensitivity, multiplexity, and accuracy.
70.
Chemical interaction between Paeonia lactiflora and Glycyrrhiza uralensis,the components of Jakyakgamcho‐tang,using a validated high‐performance liquid chromatography method: Herbal combination and chemical interaction in a decoction 下载免费PDF全文
The herbal combination is the basic unit of a herbal formula that affects the chemical characteristics of individual herbs. In the present study, a method of simultaneous determination of the 11 marker compounds in Jakyakgamcho‐tang was developed using high‐performance liquid chromatography with photodiode array detection. The validated analytical method was successfully applied to approach the chemical interaction between Paeonia lactiflora and Glycyrrhiza uralensis in co‐decoction. In P. lactiflora, the contents of gallic acid, oxypaeoniflorin, (+)‐catechin, paeoniflorin, and benzoylpaeoniflorin were decreased, while those of albiflorin and benzoic acid were increased; in G. uralensis, the contents of liquiritin, isoliquiritin, ononin, and glycyrrhizin were decreased, when decocting two herbs together. Moreover, as the ratio between P. lactiflora and G. uralensis was increased, the contents of chemical contents from each herb were proportionally increased. However, each content of marker compound per the gram of herbal medicine was decreased as the ratio of combinative herbs increased. The results showed that P. lactiflora and G. uralensis affect the extraction efficiency of chemical compounds in a Jakyakgamcho‐tang decoction. Overall, the method established in this study was simple, rapid, and accurate, and would be useful for the determination of marker compounds and for the investigation of the chemical interaction between herbal medicines. 相似文献