• Journal of Microbiology and Biotechnology
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• v.21 no.9
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• pp.914-920
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• 2011

Vibrio cholerae utilizes mannitol through an operon of the phosphoenolpyruvate-dependent phosphotransferase (PTS) type. A gene, mtlD, encoding mannitol-1-phosphate dehydrogenase was identified within the 3.9 kb mannitol operon of V. cholerae. The mtlD gene was cloned from V. cholerae O395, and the recombinant enzyme was functionally expressed in E. coli as a $6{\times}$His-tagged protein and purified to homogeneity. The recombinant protein is a monomer with a molecular mass of 42.35 kDa. The purified recombinant MtlD reduced fructose 6-phosphate (F6P) using NADH as a cofactor with a $K_m$ of $1.54{\pm}0.1$ mM and $V_{max}$ of $320.8{\pm}7.81\;{\mu}mol$/min/mg protein. The pH and temperature optima for F6P reduction were determined to be 7.5 and $37^{\circ}C$, respectively. Using quantitative real-time PCR analysis, mtlD was found to be constitutively expressed in V. cholerae, but the expression was up-regulated when grown in the presence of mannitol. The MtlD expression levels were not significantly different between V. cholerae O1 and non-O1 strains.

• Progress in Superconductivity and Cryogenics
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• v.5 no.1
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• pp.66-70
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• 2003

In a HTS transformer, the perpendicular component of magnetic flux density ($B_r$) applied to HTS tapes of pancake windings becomes larger than that of solenoid winding, thereby decreasing the critical current in the HTS tapes. This paper introduces several methods to reduce $B_r$ applied to the HTS tapes in the transformer with double pancake windings by changing winding arrangements and the relative permeability of flux diverters. We have conducted a winding design for a single-phase 1MVA 22.9kV/6.6kV HTS transformer. We observed a change of $B_r$ due to a variation of gap-length between the high voltage windings and the low voltage windings, reciprocal arrangement and an increase of the number of the high voltage pancake. We also observed a change of Br on the HTS tapes due to variation of the relative permeability of flux diverters placed between the high voltage winding and the low voltage winding. Finally, we have designed a 1MVA 22.9kV/6.6kV HTS transformer winding using suggested methods and calculated transformer parameters by the 3D finite element method.

• Radiation Oncology Journal
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• v.1 no.1
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• pp.41-45
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• 1983

To obtain 7 MeV electron beam which is suitable for treatment of the chest wall after radical of modified radical mastectomy, the authors reduced the energy of electron beam by means by Lucite plate inserted in the beam. To determine the proper thickness of the Lucite plate necessary to reduce the energy of 9 MeV electron beam to 6 MeV, dosimetry was made by using a parallel plate ionization chamber in polystyrene phantom. Separation between two adjacent fields, 7 MeV for chest wall and 12 MeV for internal mammary region, was studied by means of film dosimetry in both polytyrene phantom and Humanoid phantom. The results were as follows. 1. The average energy of 9 MeV electron beam transmitted through the Lucite plate was reduced. Reduction was proportional to the thickness of the Lucite plate in the rate of 1.7 MeV/cm. 2. The proper thickness of the Lucite plate necessary to obtain 6 MeV electron beam from 9 MeV was 1.2 cm. 3. 7 MeV electron beam, 80% dose at 2cm depth, is adequate for treatment of the chest wall. 4. Proper separation between two adjacent electron fields, 7 MeV and 12 MeV, was 5mm on both flat surface and sloping surface to produce uniform dose distribution.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.6
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• pp.585-590
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• 2000

A hemolysin producing strain was isolated from Kum rivet estuary located in west part of Korea. In the process of identification the isolated strain was similar to V. mimicus but did not show characteristics of known Vibrio species; therefore, the strain was designated as Vibrio sp. D9 ( V. kumkang) tentatively and further identification study was carried out by comparing its bacteriological characteristics, Morphologically Vibrio sp. D9 was a typical straight roe with a polar flagellium. Among known Vibrio species no identical strains were found when using automatic bacteria identification system ($MicioLog^(TM)$system, release 4.0, Biolog Inc., USA) which evaluated the ability of metabolizing 95 kinds of carbon and nitrogen sources. Vibrio sp. D9 showed 18 and 13 different responses as compared to V. mimicus and V. cholerae, respectively. Clear hemolysis zones were observed with the strain against human and sheep blood agar plate, Hemolytic toxicity was confirmed by strong vascular permeability and fatal toxicity against mouse was also observed. Thus the strain was a pathogenic vibrio. Growth conditions for Vibrio sp. D9 were salinity of $0{\~}5.0{\%}$, pH of $6.4{\~}9.8$, temperature of $15{\~}41^{\circ}C$, respectively.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.58-59
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• 2013

본 과제에서는 3.3kV/220V, 6kVA 용량의 양방향 지능형 반도체 변압기의 새로운 회로 구성을 제안하고 그 동작과 성능을 분석하였다. 제안하는 3상 반도체변압기는 1.9kV/127V 단상 반도체 변압기 모듈 3대를 Y-결선으로 구성하였으며, 각 단상 반도체 변압기는 고압 고주파 AC-DC 정류기와 저압 양방향 DC-DC-AC 컨버터로 구성되어 있다. 제안하는 3.3kV/220V, 6kVA 3상 반도체변압기를 제작하고 실험을 통해 그 동작과 성능을 검증하였다. 먼저 1차적으로는 3상 반도체변압기의 정상동작에 대해 실험을 실시하고 그 후에는 3상 입력전압에 외란이 발생하였을 때 보상성능을 순방향 조류와 역방향 조류 2가지 경우로 나누어 실험을 실시하고 그 결과를 분석하였다. 분석한 결과 제안하는 반도체변압기는 양방향 전력흐름이 가능하고 입력전압에 Sag가 발생한 경우에도 이를 보상하여 수전단이나 부하에 전력공급이 가능함을 알 수 있었다.

• Journal of the Korean Graphic Arts Communication Society
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• v.14 no.1
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• pp.115-131
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• 1996

The PVT(pressure-volume-temperature) relation of main-chain dimer liquid crystals having structures such as $\alpha$,$\omega$-bis[(4,4`-cyanobiphenyl) oxy] alkane(CBA-n with=9, 10) were studied. these dimer liquid crystals are known to form an enantiotropic nematic mesophase. In this work, we have determined the volume change as a function of temperature and pressure by using a GNOMIX PVT apparatus. In the V-Tcurves obtaind from isobaris mearements on various pressures, volume changes were observed at the nematic-isotropiz and nematic-crystal phase transitions. The volume changes at the transition exhibit slight odd-even effect with respect to the number of methylene unit n. The values of the (S)v obtained at the NI transition for CBA-9 and -10 were 6.9 and 12.6J/mol k. The valuesof (S)v for the CN transition were estimated on the basis of DSC(differential scanning calorimetry) data: 58.8(CBA-9) and 65.3J/mol k (CBA-10). For both transition, it was found that the correction about the volume change is significant, ranging from 40% to 60% of the total transition entropy observed under constant pressure.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.517-522
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• 2020

Electron beam have many factors that affect dose distribution, so even if identical settings are used, they should be identified and used for radiation treatment, and the effects on the structures in the body are sensitive, making it difficult to investigate uniform dose distribution on tumors. In this study, a dosimeter was produced using PbI₂ which is a photoelectric material, and electrical characteristics were analyzed for 6, 9, and 12 MeV electronics in linear accelerators. The reproducibility test results showed that RSD were 1.1215%, 1.0160%, and 0.05137% respectively at 6, 9, and 12 MeV energies, indicating that the output signals were stable. The linearity evaluation results showed that the R² values of the reliability indicator for straight line trend lines were 0.9999, 0.9999, and 0.9994, respectively, at 6, 9, and 12 MeV, to confirm that the output signal was proportional to PbI₂ as dose increased. The PbI₂ dosimeter in this study is judged to be highly applicable to electromagnet measurement and is thought to be able to be used as a basic study of electron detector through photoelectric material.

• Superconductivity and Cryogenics
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• v.9 no.2
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• pp.6-9
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• 2007

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.16-23
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• 2018

Alternative technologies for sludge treatment and disposal need to be developed urgently because the amount of produced production has increased continuously. In this study, Pulsed Electric Fields (PEF) technique was applied for sludge solubilization and the performance was evaluated. The PEF equipped with electrodes coated by epoxy resin and teflon was inducted to the activated sludge suspension, and the effect of the coating materials on the solubilization was determined. In addition, the effect of the applied voltage on the solubilization yield was investigated as the applied voltage was increased from 6 to 12 and 15 kV. Sludge solubilization was not observed when the epoxy-coated electrode was used for PEF induction regardless of the applied voltage. However, sludge solubilization occurred when 12 and 15 kV were applied to the teflon-coated electrodes. The MLSS decreased to 9%, and the soluble-COD increased to 496% when the applied voltage was 15 kV. But sludge solubilization did not happen under 6 kV condition. The corona discharge was observed at applied voltages of 12 and 15 kV, (Ed- sorry but I cannot understand the following highlight) but if 6 kV, strongly indicating that the corona discharge make the sludge solubilized, which suggests that the critical voltage for sludge solubilization lies between 6 and 12 kV. Consequently, proper selection of electrode-coating materials and the applied voltage of PEF could lead to sludge solubilization by corona discharge.

• Journal of the Korean Chemical Society
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• v.18 no.6
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• pp.437-442
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• 1974

Pentacyclo ($5,3,0,0^{2,5},06{3,9},0^{4,8})-decane-6,10-dione was synthesized from the cyclopentanone in good overall yield(60%). Cyclopentanone ethylene ketal(Ⅰ) was brominated with pyridinium bromide perbromide, and the brominated ketal(Ⅱ) was converted to the dimer of cyclopentadienone ethylene ketal(Ⅲ). The ethylene ketal(Ⅲ) was again converted to the dicyclopentadiene-1,8-dione(Ⅳ). Finally, the pentacyclo ($5,3,0,0^{2,5},06{3,9},0^{4,8})-decane-6,10-dione(Ⅴ) was synthesized from the dicyclopentadilene-1,8-dione(Ⅳ) by photochemical cyclization.