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1.
Jinu Park Sang-Bum Kim Jae-Mok Ha Myung-Soo Kim Hong-Soo Park Hyun-Sik Hahm 《Korean Journal of Chemical Engineering》2001,18(4):468-474
The crystallization of the [Ga]-MFI was investigated as a function of synthesis time under atmospheric pressure. The molar
composition of the reactants was 100SiO2-Ga2O3-llNa2O-llTPABr-3500H2O. The crystallinity of the [Ga]-MFT was examined by using several analytical instruments, such as XRD, XPS, XRF, FT-IR, solid-statemas-NMR, DTG/DTA, and SEM. The [Ga]-MFI was successfully synthesized under atmospheric pressure at 97 ‡C in 72 h. It was found that
the nucleation of the [Ga]-MFI took a quite long time, but the crystallization took place very fast. It is supposed that nucleation
is the rate-controlling step in the [Ga]-MFI synthesis under atmospheric pressure. Consequently, if the induction period of
the nucleation can be shortened, it would be possible to synthesize the [Ga]-MFI commercially under atmospheric pressure. 相似文献
2.
Hyun Chul Jung Heon Sang Lee Yong Sung Chun Sang-Bum Kim Woo Nyon Kim 《Polymer Bulletin》1998,41(3):387-394
Summary
Blends of a thermotropic liquid crystalline polymer (LCP) with poly(ether imide) (PEI), poly(ether ether ketone) (PEEK), polysulfone
(PSF) and polyarylsulfone (PAS) prepared by screw extrusion have been investigated by differential scanning calorimeter and
dynamic mechanical thermal analysis. From the measured glass transition temperature (Tg) and specific heat increment (ΔCp) at the Tg, it appears that the LCP dissolves more in the PEI- and PEEK-rich phases than does the PEI and PEEK in the LCP-rich phase.
From the DSC study of PSF-LCP and PAS-LCP blends, the Tg(PSF) and Tg(PAS) of each blends are almost constant with blend composition. Therefore, it is concluded that PSF and PAS are immiscible
with LCP. The polymer-polymer interaction parameter (χ12) and the degree of disorder (y/x1) of LCP have been investigated using the Flory lattice theory in which the anisotropy of LCP is considered. The χ12 values have been calculated from the Tg data and found to be 0.181 ± 0.004 at 593 K for the PEI-LCP blends and 0.069 ± 0.006 at 623 K for the PEEK-LCP blends. Using
the previously presented method, the χ12 and y/x1 in partially miscible systems have been determined.
Received: 6 April 1998/Revised version: 8 June 1998/Accepted: 17 June 1998 相似文献
3.
Jinu Park Sang-Bum Kim Jae-Mok Ha Hong-Soo Park Hyun-Sik Hahm 《Catalysis Letters》2001,75(1-2):125-130
The crystallization of [Ga]-MFI was investigated as a function of synthesis time under atmospheric pressure. The molar composition of the reactants was 100SiO2–Ga2O3–11Na2O–11TPABr–3500H2O. The crystallinity of [Ga]-MFI was examined using several analytical instruments, such as XRD, XPS, XRF, FT-IR, solid state MAS-NMR, and DTG/DTA. [Ga]-MFI was successfully synthesized under atmospheric pressure at 97°C in 72 h. It was found that the nucleation of [Ga]-MFI took quite a long time, but the crystallization took place very fast. It is supposed that the nucleation is the rate-controlling step in [Ga]-MFI synthesis under atmospheric pressure. Consequently, if the induction period of the nucleation can be shortened, it would be possible to synthesize [Ga]-MFI commercially under atmospheric pressure. 相似文献
4.
Dong-Jin Kweon Sang-Bum Chin Hee-Ro Kwak Jae-Chul Kim Kyung-Bin Song 《Power Delivery, IEEE Transactions on》2005,20(3):1976-1983
This paper presents the analysis of ultrasonic signals by the partial discharge in a model transformer as well as by corona in the air at a shielded high-voltage laboratory. In addition, various noises onsite, a 345-kV substation, were measured and analyzed, for example, the vibration by core magnetostriction, cooling pump, cooling fan, onload tap changer (OLTC) operation, OLTC filtering unit operation, and air discharge pulse by corona on the transmission line. Therefore, electrical and mechanical noises onsite were removed using the proper narrow bandpass filter and the noise discrimination algorithm. Also, the developed online ultrasonic detector was applied to detect partial discharge in a 154-kV transformer with a warning level in C/sub 2/H/sub 2/ gas. As a result of an internal inspection, the source of partial discharge was found at the estimated position based on ultrasonic detection and its reliability was verified. 相似文献
5.
Young-In Song Kyoung-Soo Han Sang-Bum Kim So-Young Park Hae-Chang Rim 《Journal of Intelligent Information Systems》2008,31(3):265-286
In this paper, we introduce variability of syntactic phrases and propose a new retrieval approach reflecting the variability of syntactic phrase representation.
With variability measure of a phrase, we can estimate how likely a phrase in a given query would appear in relevant documents and control
the impact of syntactic phrases in a retrieval model. Various experimental results over different types of queries and document
collections show that our retrieval model based on variability of syntactic phrases is very effective in terms of retrieval
performance, especially for long natural language queries. 相似文献
6.
Empirical correlations between test methods of measuring formaldehyde emission of plywood, particleboard and medium density fiberboard 总被引:1,自引:0,他引:1
Byung-Dae Park Eun-Chang Kang Sang-Bum Park Jong Young Park 《Holz als Roh- und Werkstoff》2011,69(2):311-316
Since different test methods of measuring the formaldehyde emission (FE) from wood-based composite panels have been used for different countries and regions, this study attempted to establish empirical correlations between three test methods (i.e., 24-hour desiccator, 1 m3 chamber, and perforator) for plywood (PLW), particleboard (PB), and medium density fiberboard (MDF), particularly emphasizing on correlations between the 24-hour desiccator and the 1 m3 chamber method. The desiccator method found statistically high correlations with other two methods, resulting in regression coefficient values ranging from 0.96 to 0.88 for PLW, PB, and MDF samples. In particular, the desiccator method had an empirically high correlation with the 1 m3 chamber method that had been adopted as the reference method of comparing regionally different test methods of measuring the FE of wood-based composite panels by the ISO/TC89. 相似文献
7.
Kim SJ Lee JK Kim JW Jung JW Seo K Park SB Roh KH Lee SR Hong YH Kim SJ Lee YS Kim SJ Kang KS 《Journal of materials science. Materials in medicine》2008,19(8):2953-2962
Stem cell-based therapy has recently emerged for use in novel therapeutics for incurable diseases. For successful recovery from neurologic diseases, the most pivotal factor is differentiation and directed neuronal cell growth. In this study, we fabricated three different widths of a micro-pattern on polydimethylsiloxane (PDMS; 1, 2, and 4 microm). Surface modification of the PDMS was investigated for its capacity to manage proliferation and differentiation of neural-like cells from umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs). Among the micro-patterned PDMS fabrications, the 1 microm-patterned PDMS significantly increased cell proliferation and most of the cells differentiated into neuronal cells. In addition, the 1 microm-patterned PDMS induced an increase in cytosolic calcium, while the differentiated cells on the flat and 4 microm-patterned PDMS had no response. PDMS with a 1 microm pattern was also aligned to direct orientation within 10 degrees angles. Taken together, micro-patterned PDMS supported UCB-MSC proliferation and induced neural like-cell differentiation. Our data suggest that micro-patterned PDMS might be a guiding method for stem cell therapy that would improve its therapeutic action in neurological diseases. 相似文献
8.
Sang-Bum Kim Hee Eun Kang Hyun-Jong Cho Yeong Shik Kim Suk-Jae Chung 《Drug development and industrial pharmacy》2016,42(2):263-269
Magnolol (MAG; 5,5′-diallyl-2,2′-biphenyldiol) is a major bioactive component of Magnolia officinalis. We investigated the metabolic interactions of MAG with hepatic cytochrome P450 monooxygenase (CYP) through in vitro microsomal metabolism study using human (HLM) and rat liver microsomes (RLM). CYP2C and 3A subfamilies were significantly involved in the metabolism of MAG, while CYP1A subfamily was not in HLM and RLM. The relative contribution of phase I enzymes including CYP to the metabolism of MAG was comparable to that of uridine diphosphate glucuronosyltransferase (UGT) in RLM. Moreover, MAG potently inhibited the metabolic activity of CYP1A (IC50 of 1.62?μM) and 2C (IC50 of 5.56?μM), while weakly CYP3A (IC50 of 35.0?μM) in HLM and RLM. By the construction of Dixon plot, the inhibition type of MAG on CYP activity in RLM was determined as follows: uncompetitive inhibitor for CYP1A (Ki of 1.09–12.0?μM); competitive inhibitor for CYP2C (Ki of 10.0–15.2?μM) and 3A (Ki of 93.7–183?μM). Based on the comparison of the current IC50 and Ki values with a previously reported liver concentration (about 13?μM) of MAG after its seven times oral administration at a dose of 50?mg/kg in rats, it is suggested that MAG could show significant inhibition of CYP1A and 2C, but not CYP3A, in the in vivo rat system. These results could lead to further studies in clinically significant metabolism-mediated MAG–drug interactions. 相似文献
9.
Sang-Bum Kim Young-Kook Kim Yun-Su Lim Myung-Soo Kim Hyun-Sik Hahm 《Korean Journal of Chemical Engineering》2003,20(6):1023-1025
A mechanistic study on the partial oxidation of methane to synthesis gas (H2 and CO) was conducted with supported nickel catalysts. To investigate the reaction mechanism, pulse experiments, O2-TPD, and a comparison of the moles of reactants and products were carried out. From the O2-TPD experiment, it was observed that the active catalyst in the synthesis gas production desorbed oxygen at a lower temperature.
In the pulse experiment, the temperature of the top of the catalyst bed increased with the pulses, whereas the temperature
of the bottom decreased. This suggests that there are two kinds of reactions, that is, the total oxidation of methane (exothermic)
at the top and reforming reactions (endothermic) at the bottom. From the comparison of the moles of reactants and products,
it was found that the moles of CO2, CH4 and H2O decreased as the moles of H2 and CO increased. The results support the mechanism that synthesis gas is produced through a two-step reaction mechanism:
the total oxidation of methane to CO2 and H2O takes place first, followed by the reforming reaction of the produced CO2 and H2O with residual CH4 to form synthesis gas.
This paper is dedicated to Professor Hyun-Ku Rhee on the occasion of his retirement from Seoul National University. 相似文献
10.
Lee Jae-Sung Lim Ji-Na Wang Tao Lee Sang-Bum Hwang Jin-Hee Jung U-Suk Kim Min-Jeong Choi Seong-Ho Ishizuka Satoshi Lee Hong-Gu 《Food science and biotechnology》2016,25(1):275-281
Food Science and Biotechnology - Direct influences of dietary trans-11 18:1 vaccenic acid (TVA) at physiological concentrations of 50-200 μM were evaluated for cell growth, cytotoxic activity,... 相似文献