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1.
Won Young Jung Seung Hee Baek Seong Soo Park Gun-Dae Lee Euh Duck Jeong Hyun Gyu Kim Seong-Soo Hong 《Reaction Kinetics and Catalysis Letters》2007,91(2):233-240
The nanosized titania and TiO2/SiO2 particles were prepared by the microwave-hydrothermal method. The effect of physical properties TTIP/TEOS ratio and calcination
temperature has been investigated. The major phase of the pure TiO2 particle is of the anatase structure, and a rutile peak was observed above 800°C. In TiO2/SiO2 particles, however, no significant rutile phase was observed, although the calcination temperature was 900°C. No peaks for
the silica crystal phase were observed at either silica/titania ratio. The crystallite size of TiO2/SiO2 particles decreases as compared to pure TiO2 at high calcination temperatures. The TiO2/SiO2 particles show higher activity on the photocatalytic decomposition of orange II as compared to pure TiO2 particles. 相似文献
2.
Yinam Li Tae‐Hoon Kim Qinghua Zhao Euh‐Kyung Kim Seung‐Hon Han Yun‐Hi Kim Jin Jang Soon‐Ki Kwon 《Journal of polymer science. Part A, Polymer chemistry》2008,46(15):5115-5122
We have designed and synthesized a new polymer, which could be used in the organic thin film transistor (OTFT). Poly[2,6‐bis(3′‐dodecythiophene‐2′‐yl)anthracene] (PDTAn), which is composed with anthracene moiety and dodecyl alkyl thiophene, was synthesized by oxidative polymerization using iron (III) chloride. The mole ratio of FeCl3 and monomer (4.2:1), keeping low temperature during the initiation reaction, amount of solvent, and dropping order were very important for oxidative polymerization without crosslinking. The molecular weight of the polymer (Mw) was measured to be 40,000 with 2.85 of polydispersity index by GPC. The physical and optical properties of the polymer were characterized by differential scanning calorimetry (DSC), cyclic voltammetry (CV), and optical absorption and photoluminescence (PL) spectroscopy. A field‐effect mobility of 1.1 × 10?4 cm2 V?1 S?1, a current on/off ratio of 105, and the Vth at ?15.2 V had been obtained for OTFTs using this polymer semiconductor by solution coating. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5115–5122, 2008 相似文献
3.
Tae Kyu Kim Euh Duck Jeong Chae Young Oh Min Seob Shin Jong-Pil Kim Ok-Sang Jung Hongsuk Suh Fazlur Rahman Nawaz Khan Myung Ho Hyun Jong Sung Jin 《Chemical Papers》2011,65(6):863-872
A series of neutral gelators and cationic amphiphiles derived from 1,2 diphenylethylenediamine (I) and 1,2-cyclohexanediamine (II) was synthesised. Helical silica nanotubes were prepared utilising these organic gelators through sol-gel polycondensation
of tetraethoxy silane, (TEOS-silica source). Right- and left-handed helical nanotubes respectively were obtained from a 1:
1 mass mixture of optically active, (1S,2S)-III-(1S,2S)-V neutral gelator and (1S,2S)-IV-(1S,2S)-VI cationic amphiphile and a 1: 1 mass mixture of optically active, (1R,2R)-III-(1R,2R)-V neutral gelator and (1R,2R)-IV-(1R,2R)-VI cationic amphiphile, indicating that the handedness of the helical nanotubes varied with the change in the neutral gelator
precursors used. The nanotubes were characterised by SEM images. 相似文献
4.
We recall a curvature identity for 4-dimensional compact Riemannian manifolds as derived from the generalized Gauss–Bonnet formula. We extend this curvature identity to non-compact 4-dimensional Riemannian manifolds. We also give some applications of this curvature identity. 相似文献
5.
Yunhee Euh JeongHyeong Park Kouei Sekigawa 《Differential Geometry and its Applications》2013,31(4):463-471
We give an integral formula for the first Pontrjagin number of a compact almost Hermitian surface and derive curvature identities from the integral formula based on the fundamental fact that the first Pontrjagin number in the deRham cohomology group is a topological invariant. Further, we provide some applications of the identities. 相似文献
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7.
A weakly Einstein manifold is a natural generalization of a 4-dimensional Einstein manifold. In this paper, we shall give a characterization of a weakly Einstein manifold in terms of so-called generalized Singer-Thorpe bases. As an application, we prove a generalization of the Hitchin inequality for compact weakly Einstein 4-manifolds. Examples are provided to illustrate the theorems. 相似文献
8.
Cho SJ Jung JS Shin SC Jin I Ko BH Kim Kwon Y Suh-Kim H Moon IS 《Experimental & molecular medicine》2003,35(6):486-493
The 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP), a protein of unknown function in vivo, is abundantly expressed in myelinating glia in two isoforms, CNP1 and CNP2. In this study, immunoblot analysis showed that CNP1 is the major isoform in adult forebrain, and that both isoforms are included in the postsynaptic density (PSD) fraction and tyrosine-phosphorylated at the basal level. However, subcellular distribution and detergent extraction data showed that CNP is nonspecifically associated with the PSD fraction. Immunocytochemistry revealed that CNP is detected, in a weak but punctate pattern, in dissociated rat hippocampal neurons of 3 days to 2 weeks in vitro. The CNP-positive punctae were distributed throughout soma and dendrites, and distinct from PSD95-positive ones. Immunoblot analysis indicated that CNP is also expressed in neuronal stem cell lines, HiB5 and F11. Interestingly, in addition to the known two isoforms, a new CNP isoform of MW 45 kDa was expressed in these cell lines and was the major type of isoform in F11 cells. Taken together, our data suggest that CNP is expressed in the early stage of in vitro development and nonspecifically included in the adult rat PSD fraction. 相似文献
9.
Erdene‐Ochir Ganbold Yunhee Lee Kangtaek Lee Prof. Ohyun Kwon Dr. Sang‐Woo Joo Prof. 《化学:亚洲杂志》2010,5(4):852-858
The interfacial behavior of self‐assembled thin films of benzoic acid (BA) and phenylphosphonic acid (PPOA) anchored on TiO2 surfaces was studied by using temperature‐dependent diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. On the basis of the disappearance of the OH band from the infrared spectra at room temperature, BA and PPOA appear to adsorb onto TiO2 surfaces through carboxylate and phosphonate groups, respectively. Above 420 °C, DRIFT spectra indicated that both BA and PPOA desorb from TiO2 surfaces; however, dissimilar desorption behavior could be inferred for BA and PPOA from their temperature‐dependent spectral changes. The benzene ring modes of PPOA remained above 420 °C, whereas those of BA disappeared. Density functional theory calculations showed that the adsorption of BA and PPOA on TiO2 surfaces corresponded to bidentate bridging geometry on TiO2 surfaces, and the adsorption of PPOA is stronger than that of BA. The monodentate structures with energy differences of 4.9 and 9.1 kcal mol?1 from the most stable bidentate structures of BA and PPOA, respectively, from the DFT calculations appeared to be possible, particularly at the high temperatures above 420 °C, as indicated by the intensified OH bands. The geometry of PPOA was also estimated to be more upright standing than that of BA on TiO2 surfaces, which may lead a rather straight detachment from the TiO2 surfaces based on the presence of in‐plane ring modes in the DRIFT spectra at the higher temperature. 相似文献
10.
Interfacial area concentration (IAC) is one of the most important parameters in the two-phase flow models. Five-sensor probe method is a useful measurement technique to measure an IAC. It is essentially based on the four-sensor probe method but it is improved by adapting one more sensor. The passing types of the interfaces through the sensors are classified into four categories and independent methods are applied to the interfaces belonging to each category. To verify the applicability of the five-sensor probe method, benchmarking tests are performed for a rectangular visual channel by using the photographic method. The bubble velocity, void fraction, and Sauter mean diameter measured by the probe are also benchmarked. This paper also includes the design of the five-sensor conductivity probe, the IAC measurement method, the signal processing procedure of the probe signal and the data analysis method by photography. 相似文献