• 한국결정성장학회지
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• 제19권3호
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• pp.125-129
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• 2009

The preparation and characterization of niobium carbide crystallites were investigated in this study, and in particular, the effect of preparation conditions were studied on the synthesis of niobium carbides crystallites. For this purpose, various characterization techniques including x-ray diffraction, BET surface area, and oxygen uptake measurements were employed to characterize the synthesized niobium carbide crystallites. The niobium carbide crystallites were prepared using niobium oxide and methane gas or methane-hydrogen mixture. Using x-ray diffraction a lattice parameter of $4.45{\AA}$ and a crystallite size ranging from $52{\AA}$ to $580{\AA}$ was found. BET surface areas ranged from $3.2\;m^2/g$ to $16.6\;m^2/g$ and oxygen uptake values varied from $0.5{\mu}mol/g$ to $6.1{\mu}mol/g$. It was observed that niobium carbide crystallites were active for ammonia decomposition reaction. While the BET surface area increased with increasing the oxygen uptake, the conversion of ammonia decomposition reaction decreased. These results indicated that the ammonia decomposition over these materials was considered to be structure-sensitive.

• 생약학회지
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• 제41권1호
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• pp.48-53
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• 2010

GCSB-5 preparation is a purified extract from a mixture of 6 medicinal plants(Acanthopanacis Cortex, Achyranthis Radix, Saposhnikoviae Radix, Cibotii Rhizoma, Glycine Semen Nigra, Eucommiae Cortex) that have been widely used for the treatment of various bone disorders. The aim of this study was to investigate HPLC analysis method and screening of standard compound on Cibotii Rhizoma for quality standardization of a medicinal crude drug GCSB-5. Onitin-4-O-$\beta$-D-glucopyranoside was isolated from Cibotii Rhizoma as the standard compound and identified on the basis of spectroscopic data such as NMR. HPLC analysis method for the determination of onitin-4-O-$\beta$-D-glucopyranoside was established for the quality control of the medicinal plants of Cibotii Rhizoma species, GCSB-5 raw material and GCSB-5 preparation. And validation of HPLC analysis methods were conformed for verification of HPLC methods by check to specificity, linearity, intra-day precision, inter-day precision and accuracy following ICH guideline.

• 대한약리학회지
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• 제12권1호
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• pp.69-73
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• 1976

A combined syrup preparation of pyrantel pamoate and oxantel pamoate containing 50mg/ml of respective anthelminthics was evaluated on the efficacy to treat the human intestinal nematodes. Total 24 cases were treated with oral administration of above preparation 10 mg/kg body weight by single dose. The results were summarized as follows: 1. Out of 21 cases of Ascaris lumbricoides infection, 19 (90.5%) turned to be egg negative on 21 days after treatment and egg-reduction rate was 99.7%. 2. 17 cases out of 19 cases infected with Trichocephalus trichiurus were egg negative after treatment (84.2%) and egg reduction rate was 60.6%. 3. As for Ancylostoma duodenale infection, egg negative conversion rate was 88.9% and egg reduction rate was 98.1% by single oral administration among 9 infected cases. 4. In Enterobius vermicularis infection, all of 17 cases gave negative anal swab on 21th day after the treatment. From the above results, it was assumed that the anthelminthic activities of pyrantel pamoate and oxantel pamoate were not potentiated by the mixture of two kinds of drugs but showed simple additive effect.

• Journal of Pharmaceutical Investigation
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• 제32권4호
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• pp.299-303
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• 2002

The oral bioavailability of itraconazole is variable and low in fasting state. This is mainly due to the low solubility of this drug. Bioavailability can be improved by changing the formulation and it is general that the liquid preparations show greater bioavailability than the solid dosage forms such as tablets and capsules do. Benzyl alcohol-water binary mixture showed the excellent solubilizing capacity for itraconazole but the release of the drug from the preparation needs to be enhanced. In this study, various nonionic surfactants and hydrophilic polymers, poloxamers, were screened to investigate their effects on the releasε of itraconazole from the liquid preparations. Poloxamer 407 showed the most enhancing effect on the drug release and the release rate was proportional to thε amount of poloxamer 407 added. A liquid preparation of itraconazole, consisting of benzyl alcohol/water/poloxamer 407 ternary solvent system, releasεd more than 80% of the total drug amount at 5 min and showεd the possibility of a new formulation development.

• Journal of Applied Biological Chemistry
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• 제55권1호
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• pp.13-17
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• 2012

In order to enzymatically produce chitooligosaccharide using the crude enzyme preparation from Bacillus cereus D-11, we first studied the optimal reaction conditions. It was found that the optimal temperature for hydrolysis of chitosan was $55^{\circ}C$. The ratio of enzyme/substrate should not be lower than 0.13 U/mg in the reaction mixture. The enzyme activity was stable below $50^{\circ}C$. The products of enzymatic reaction were analyzed by both thin layer chromatography and high performance liquid chromatography. Under the appropriate condition, chitosan was hydrolyzed using the enzyme preparation. The resulting chitooligosaccharides were purified and separated by Dowex ($H^+$) ion exchange chromatography. From 4 g soluble chitosan, 0.95 g $(GlcN)_2$, 1.43 g $(GlcN)_3$, and 1.18 g $(GlcN)_4$ were recovered.

• Geomechanics and Engineering
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• 제36권3호
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• pp.247-258
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• 2024

Tailings are waste materials of mining operations, consisting of a mixture of clay, silt, sand with a high content of unrecoverable metals, process water, and chemical reagents. They are usually discharged as slurry into the storage area retained by dams or earth embankments. Poor knowledge of the hydro-mechanical behaviour of tailings has often resulted in a high rate of failures in which static liquefaction has been widely recognized as one of the major causes of dam collapse. Many studies have dealt with the static liquefaction of coarse soils in saturated conditions. This research provides an extension to the case of silty tailings in unsaturated conditions. The static liquefaction resistance was evaluated in terms of stress-strain behavior by means of monotonic triaxial tests. Its dependency on the preparation method, the volumetric water content, the void ratio, and the degree of saturation was studied and compared with literature data. The static liquefaction response was proved to be dependent mainly on the preparation technique and degree of saturation that, in turn, controls the excess of pore pressure whose leading role is investigated by means of the relationship between the -B Skempton parameter and the degree of saturation. A preliminary interpretation of the static liquefaction response of Stava tailings is also provided within the Critical State framework.

• Food Science and Biotechnology
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• 제18권2호
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• pp.570-573
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• 2009

The debranching enzyme of Nostoc punctiforme (NPDE) is a novel enzyme that catalyzes the hydrolysis of $\alpha$-1,6-glycosidic linkages in starch, followed by the sequential hydrolysis of $\alpha$-1,4-glycosidic linkages. The debranching activity of NPDE is highly specific for branched chains with a degree of polymerization (DP)>8. Moreover, the rate of hydrolysis of $\alpha$-1,4-linkages by NPDE is greatly enhanced for maltooligosaccharides (MOs) with a DP>8. An analysis of reaction mixtures containing various starches revealed the accumulation of maltooctaose (G8) with glucose and maltose. Based on the novel enzymatic properties of NPDE, an MO mixture containing more than 60% G8 with yield of 18 g G8 for 100 g starch was prepared by the reaction of NPDE with soluble starch, followed by ethanol precipitation and gel permeation chromatography (GPC). The yield of the G8-rich mixture was significantly improved by the addition of isoamylase. In summary, a 4-step process for the production of a G8-rich mixture was developed involving the enzymatic hydrolysis of starch by NPDE.

• 한국광학회:학술대회논문집
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• 한국광학회 2002년도 하계학술발표회
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• pp.196-197
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• 2002

졸-겔법은 비정질이나 결정질의 산화물 박막을 제작하는 유용한 방법중 하나이다.(1) 또한 졸-겔법은 제작하고자 하는 특성의 시편을 비교적 쉽게 구현할 수 있다는 장점이 있다. TiO$_2$와 SiO$_2$ 박막은 비교적 큰 굴절률 차이를 갖고 있어 혼합비에 따라 넓고 완만한 굴절률 분포를 가진다.(2) 이것은 박막이 원하는 광학적 특성을 가지게 하여 광학이나 촉매 분야에 응용할 수 있는 가능성이 크다는 것을 의미한다. (중략)

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2004년도 추계학술발표회 발표논문집
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• pp.1128-1129
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• 2004

• 한국산학기술학회논문지
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• 제4권3호
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• pp.260-262
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• 2003

A thermal vapor deposition method for crystallization of insoluble analytes with matrix is established as a new sample preparation method for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). A mixture of mono, bis and tris(p-ethyl benzylidene) sorbitols was incorporated into microcrystals of ferulic acid, which was confirmed by confocal micrographs. Molecular masses of sorbitol derivatives were determined in this way by MALDI-MS without thermal decomposition.