• Microbiology and Biotechnology Letters
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• v.27 no.3
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• pp.260-265
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• 1999

The structural $\beta$-galactosidase gene (lacZ) from Lactococcus lactis ssp. lactis 7962 was cloned into plamid vector pKF18, which was designated as pKF-gal. Expression of the lacZ from L. lactis 7962 was found to be higher when cells were grown at 3$0^{\circ}C$ than 37$^{\circ}C$. Maximum $\beta$-galactosidase activity was obtained when E. coli/pKF-gal was cultivated for 6hr at 3$0^{\circ}C$ and for 3hr at 37$^{\circ}C$, and L. lactis 7962 was grown for 8hr at 3$0^{\circ}C$. Enzyme induction was achieved by the addition of lactose, galactose, or lactose+IPTG to growing culture. The addition of glucose had no effect on enzyme induction.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.750-751
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• 2007

본 논문에서는 고압 모터의 절연열화 상태를 감시하기 위해 소선단락, 도체표면 공극, 주절연재료 내부공극, 반도전체 제거, 정상권선으로 모델권선을 제작하고 이 모델 권선에 고전압을 인가하여 shering bridge를 이용하여 교류전류의 변화분 및 정전용량, 유전정접 시험을 하였다. 이를 통해 얻어진 결과는 고압 모터의 고정자 권선의 절연상태를 판단하는 중요한 기초자료가 될것으로 판단한다.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.171-175
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• 2003

The putative endochitinase gene, yheB of Escherichia coli K-12 is not expressed under lab culture conditions. The endochitinase gene was amplified by PCR and subcloned into pET28c vector and pQE9 vector, respectively. The endochitinase produced in E. coli harboring pET28c containing yheB or pQE9 vector containing yheE was partly released into the growth medium. The overproduced endochitinase was partially purified by His affinity column chromatography and DE-52 column chromatography. The apparent molecular weight of the endochitinase determined by SDS-polyacrylamide gel electrophoresis was about 97,000. The purified E. coli endochitinase showed maximal chitinolytic activity at pH 6 and $40^{\circ}C$.

• Journal of radiological science and technology
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• v.21 no.1
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• pp.59-64
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• 1998

[ $CaSO_4$ ] thermoluminescent phosphors was made by sintring the $CaSO_4$ after doping the transition elements Tm, Pd, Dy, V, Mo, Zr. The maximum Peaks are found in the measured $CaSO_4$(Tm, Pd, Dy, V, Mo, Zr) TL glow curve at $130^{\circ}C,\;110^{\circ}C,\;140^{\circ}C,\;100^{\circ}C$, and $120^{\circ}C$ when the heating rate is $5^{\circ}C/sec$. The activation energy of the main peak has been estimated by the peak shape method. The estimated activation energies are 1.02eV, 1.32eV, 1.12eV, 0.80eV, and 1.17eV, respectively. The thermoluminescence process in $CaSO_4$(Tm, Pd, Dy, V, Mo, Zr)are found to the 2nd order when the main peak of the glow curve is analyzed by peak shape method. The dose responses of $CaSO_4$(Tm, Pd, Dy, V, Mo, Zr) phosphors are linear within $4{\times}10^{-4}{\sim}1Gy$ of X-rays.

• YAKHAK HOEJI
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• v.58 no.5
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• pp.314-321
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• 2014

Cibotii Rhizoma, the dried rhizome of Cibotium barometz J. Smith (C. barometz), has long been used to treat bone or nervous system disorders. In this regard, we isolated three main phenolic compounds, onitin-4-O-${\beta}$-D-glucopyranoside (1), irisdichototins E & F epimeric mixture (2), and protocatechuic acid (3) from C. barometz methanol extract. In addition, we screened their antioxidative activities by DPPH, ABTS radical, and superoxide scavenging assays. Among these three compounds, irisdichototins E & F and protocatechuic acid showed strong antioxidant activities. Also, the antioxidant activities of the C. barometz extracts were proportional to the contents of irisdichototins E & F and protocatechuic acid, thus these two phenolic compounds could be main active compounds of C. barometz. In addition, onitin-4-O-${\beta}$-D-glucopyranoside is considered as a marker compound of C. barometz because this compound is specifically contained in C. barometz which belongs to Pteridophyta order. A rapid analysis method for the simultaneous determination of phenolic compounds was also developed by UPLC (Ultra Performance Liquid Chromatography). Using the developed method, the two active compounds (irisdichototins E & F and protocatechuic acid) and a marker compound (onitin-4-O-${\beta}$-D-glucopyranoside) were successfully quantified in 14 commercial samples that were collected from different regions.

• Progress in Superconductivity and Cryogenics
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• v.24 no.1
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• pp.18-22
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• 2022

The effect of electron beam (EB) irradiation on superconducting properties and microstructures of MgB₂ bulk superconductors were investigated. At E-beam doses of 1×10¹⁶ e/cm² and 1×10¹⁷ e/cm², the effect of irradiation on a superconducting transition temperature (T_c) of MgB₂ was weak. As a dose increases to 5×10¹⁷ e/cm², T_c decreases by 0.5 K. The critical current density (J_c) measured at 4.2 K and 20 K, and 0 T - 5 T increases slightly as exposure time increases. X-ray diffraction for the irradiation surface of MgB₂ shows that the diffraction intensity of (hkl) peaks decreases proportionally as the exposure time increases. This indicates that the crystallinity of MgB₂ was degraded by irradiation. TEM investigation for the irradiated sample showed distorted lattice structure, which is consistent with the XRD results. The J_c increase and T_c reduction of MgB₂ by irradiation are believed to be caused by the lattice distortion.

• International Commerce and Information Review
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• v.7 no.4
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• pp.23-36
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• 2005

With the rapid development of the Internet, e-business has been entering a new phase. However, there're still some problems to be settled and needs for breakthrough. The paper proposes an innovative approach to e-business models with the aim to resolve the problems. The paper reviews the exiting e-commerce models and points out some of the common weaknesses of the models, and presents the "Business Blogging e-Hub"model for e-business. With the characteristics of all-sided information, multi-dimensional interactivity and trans-model e-commerce platform, the proposed model is created and derived from the integration of the "classical"e-commerce models as B2B, B2C and C2C with the technology and essence of blogging, and is thus sure to meet rapidly changing business needs.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.59-65
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• 2008

The equilibrium solubilization capacity of the mixture of hydrocarbon oils by $C_{12}E_8$ nonionic surfactant micellar solution was measured at $23^{\circ}C$ by gas chromatography (GC) analysis. Experimental results indicated that the solubilization capacity for pure alkanes was found to decrease almost linearly with the alkane carbon number (ACN) of the hydrocarbon oil. For the binary mixture systems of the hydrocarbon oils both selective and nonselective solubilization behaviors were observed depending on the difference in ACN of the two hydrocarbon oils. Equilibrium solubilization tests for the hydrocarbon oil mixtures in $C_{12}E_8$ surfactant solutions such as the three n-octane/n-nonane, n-nonane/n-decane and n-decane/n-undecane mixture systems suggest almost non-selective solubilization. On the other hand, the n-octane/n-decane and n-octane/n-undecane systems, where difference in ACN of the two hydrocarbon oils is greater than 1, selective solubilization in favor of n-octane was conclusively demonstrated.

• Korean journal of food and cookery science
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• v.7 no.4
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• pp.71-86
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• 1991

This study was attempted to enhance nutritional value of cooked rice by adding milk in cooking water. Cooked and soaked rice with five different levels of milk in cooking water (0%, A: 30%, B: 50%, C: 70%, D: 100%, E) was tested for rheological parameters, fine structural changes, sensory evaluation. 1. Water absorbance of raw rice in cooking water with varying amountes of milk, was tested at $5^{\circ}C$ and $15^{\circ}C$ for 2 hours. Water absorption ratio was decreased as milk content was increased and soaking temperature was low. Time for maximum water absorption of sample A was 40 min at 1$15^{\circ}C$ but for sample B to D, it was not reached until 120 min. 2. Electronmicroscopic observation revealed that starch granules of rice lost their regular forms by soaking for 90 minutes, but recovered most of initial regularity after 24 hours. Increase in milk content of soaking water decreased marginal sharpness of the starch granule, presumably due to reduced swelling of the granule. 3. Degree of gelatinization of cooked rice was highest in sample A and progressively decreased as milk content was increased. It was, however, increased in all samples when the cooking water to rice ratio was raised from 160% to 180%. During 4 hour storage, rates of retrogradation were not different between A and B samples, but those of C, D and E were about 2.5 times higher than A and B under the optimal condition of 170% cooking water to rice ratio. This was in the order reverse to hardness order of AC>A, D＞E at cooking water to rice ratios of 160% and 170%, above which A sample surpassed the rest of samples. 4. Sensory evaluation conducted by fifteen university students as panelists showed that there were more significant differences among five samples in flavour, texture than appearance and a notable preference for b and C over A, D and E.

• Fire Science and Engineering
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• v.17 no.4
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• pp.13-19
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• 2003

In this paper, we studied on the characteristics of RCD(Residual Current Device) case deteriorated by tracking, and compared the tracked samples between in the site of fire($S_1$) and in the reappearance experiment($E_1$). This experiment is applied to IEC Publ. 112 method. Electrical fire by tracking occurred after scintillation and dry-band generated. The insulation resistance between source terminals of RCD case was about 25.7Ω in $E_1$ and the resistance was about 58.6Ω in $S_1$.The exothermic peaks of $E_1$ appeared at $491.0^{\circ}C$ and $603.2^{\circ}C$. The exothermic peak at $603.2^{\circ}C$ was shown by tracking. And the exothermic peak of $S_1$ appeared at $593.1^{\circ}C$. In spectrum of $S_1$ and $E_1$, absorption peak didn't appear at near 1590 cm$^{-1}$ .