• Microbiology and Biotechnology Letters
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• v.26 no.2
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• pp.102-109
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• 1998

To investigate the increased acid tolerance of a acid-resistant mutant Leuconostoc mesenteroides M-100 improved as a kimchi starter, proton permeability, ATPase acitivity, glycolysis activity, $Mg^{2+}$ releasement, and membrane fatty acid composition were studied and comprised with its wild type Leuconostoc mesenteroides Mw. In the proton permeability experiment, the mininum values of the average half time ($t_{1/2}$) of pH equilibration through the cell membrane of the Mw and the M-100 were about 8.6 min and 9.2 min in 150 mM KCI solution, respectivily. In the 3% NaCl solution, the $t_{1/2}$ values of the Mw and the M-100 were 6min and 8.6 min, respectivily. The values and pHs of maximal specific activities of ATPase originated from the Mw and the M-100 were 0.6U at pH 5.5 and 0.8U at pH 5.5, respectivily. The result of pH dependence of glycolysis showed that the M-100 had higher activities than that of Mw except at pH 5.0. The releases of magnesium from the Mw and the M-100 were observed about 36.5% and 13% at pH 4.0 after 2 hours, respectivily. The results of comparison of membrane fatty acid composition of the Mw with the M-100 showed that $C_{12}$, $C_{14}$, $C_{18:1}$, and $C_{19:0cyclo}$ were major different fatty acids between two strains and the content of $C_{18:1}$, and $C_{19:0cyclo}$ were 23.4%, 10.2% in the Mw and 15.1%, 12.2% in the M-100. These results indicated that acid tolerance of the M-100 was significantly improved in comparison with its wild type Mw.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.1
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• pp.38-43
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• 2012

Purpose: Patients injected with FDG use the bathroom that Measured surface contamination level and spatial dose rate. This study about the effect that result affects workers in same part. Materials and Methods: Group1 is St. Vincent' s hospital's 60case. Group 2 is Bucheon St. Mary's hospital's 50case. Last case is lower the average daily number of patients than group 2. Measured time is 8:00, 10:00, 13:00, 15:00 and 17:00. Measured part is 4 point of toilet, basin and wastepaper basket, also measured accumulation dose of toilet during 3 month. Hospitals is installed PET/CT ware surveyed on presence of bathroom that used only by patient and worker has been using the bathroom. Results: The highest average surface contamination level of toilet is group1($8.38{\pm}4.56$), but the highest spatial dose rate is group3. Cumulative exposure dose measured by TLD during 3months is St.Vincent's hospital 0.78 mSv and Bucheon St.Mary's hospital 0.37 mSv. And result of survey is 16.12% worker using the bathroom. Conclusions: The more daily number of patient, the higher surface contamination level of bathroom. Especially, wastepaper basket's surface contamination level is exceed the reference value $4Bq/cm^2$. Based on This survey, Bathroom require special attention and proper decontamination.

• The Korean Journal of Nuclear Medicine
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• v.32 no.5
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• pp.425-432
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• 1998

Purpose: For the purpose of using Re-188 as a therapeutic radionuclide, we performed the quality control of the W-188/Re-188 generator system. Materials and Methods: Several quality control tests of the Re-188 eluate from generator were carried out for about 300 days. After elution of Re-188 with normal saline (20 ml), chromatogram and gamma-ray spectrum of Re-188 eluate were obtained. The presence of aluminum which was derived from the alumina bed of the generator was detected by using aluminum ion indicator kit. Re-188 eluate was allowed to decay for several days, and then W-188 breakthrough in the Re-188 eluate was measured by detecting gamma-ray at 227 keY and 290 keV. The pH and the pyrogenicity of the eluate were checked. The Re-188 bolus was concentrated with ion exchange columns. Results: The radioactivity of Re-188 eluate from the generator was $67.4{\pm}7.0%$ of W-188 during 270 days, and it was highest at third day after previous elution. Radiochemical purity of Re-188 eluate obtained from chromatogram was higher than 99%. Gamma-ray spectrum of Re-188 eluate showed a peak at 155 keV. Aluminum ion and W-188 contamination were not detected. The PH of Re-188 eluate was 3 and the concentration yield was 85%. Conclusion: Our experiments and results on quality control tests of Re-188 eluate from W-188/Re-188 generator may be useful for setting W-188/Re-188 generator in hospitals.

• Progress in Medical Physics
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• v.21 no.3
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• pp.291-297
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• 2010

This study examined the dosimetric influence of implanted gold markers in proton therapy and the effects of their positions in the spread-out Bragg peak (SOBP) proton beam. The implanted cylindrical gold markers were 3 mm long and 1.2 mm in diameter. The dosimetric influence of the gold markers was determined with markers at various locations in a proton-beam field. Spatial dose distributions were measured using a three-dimensional moving water phantom and a stereotactic diode detector with an effective diameter of 0.5 mm. Also, a film dosimetry was performed using Gafchromic External Beam Treatment (EBT) film. The GEANT4 simulation toolkit was used for Monte-Carlo simulations to confirm the measurements and to construct the dose-volume histogram with implanting markers. Motion data were obtained from the portal images of 10 patients to investigate the effect of organ motions on the dosimetric influence of markers in the presence of a rectal balloon. The underdosed volume due to a single gold marker, in which the dose was less than 95% of a prescribed amount, was 0.15 cc. The underdosed volume due to the presence of a gold marker is much smaller than the target volume. However, the underdosed volume is inside the gross tumor volume and is not smeared out due to translational prostate motions. The positions of gold markers and the conditions of the proton-beam field give different impacts on the dose distribution of a target with implanted gold markers, and should be considered in all clinical proton-based therapies.

• The Korean Journal of Mycology
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• v.16 no.4
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• pp.220-225
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• 1988

This study was carried out to investigate the effect on the system of crop rotation of sesame(Sesamum indicum L). The results of infected plant percentage and yield of sesame wilting disease, fluctuation of density of Fusarium oxysporum and Actinomycetes, and their pathogenicity test on Fusarium spp isolated from sesame cultural soil were investigated. Density of F. oxysporum was the highest in a sesame continuous cropping soil but that of Actinomycetes was the lowest in that soil. And that of F. oxysporum and Actinomycetes according to investigation date was the highest at June. 30 and July. 30, respectively. Their pathogenicity of F. oxysporum and F. solani isolated from sesame cultural soil to sesame, peanut and green gram were recognized to all isolates except one isolate among F. oxysporum 8 isolates and one isolate to sesame, 2 isolates to peanut and all isolates to green gram among F. solani 4 isolates. F. oxysporum density and infected plant of wilting disease were increased as a result of replanted cultivation of sesame, and yield of that was prominantly reduced. Relation between density of F. oxysporum in cultural soil and infected plant percentage showed positive correlation and yield index highly negative. There was little difference between sesame-upland rice and sesame-peanut in the system of crop rotation.

• The Korean Journal of Nuclear Medicine
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• v.30 no.3
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• pp.367-371
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• 1996

The $MAG_3$ is a tubular excreting radiopharmaceutical for renal image. We synthesized benzoyl $MAG_3\;(Bz-MAG_3)$ and made a kit for labeling with $^{99m}Tc$. We checked the labeling efficieny of $^{99m}Tc$ labeled $MAG_3$ and biodistribution. Labeling efficieny was checked by TLC-SG (acetonitrile/$H_2O$=2/1). After injecting of 1 mCi of $^{99m}Tc-MAG_3$ to ICR-mice, $T_{max}(min),\;T_{1/2}(min)$ were obtained in the renogram. Sequential images (30sec, 2min, 5min, 10min, 15min, 20min) of $^{99m}Tc-MAG_3$ were compared with those of commercial $^{99m}Tc$-DTPA (Du Pont Merck Pharmaceutical Co.) kit. 1) The $R_f$ value of synthesized $^{99m}Tc-MAG_3$ was 0.78 and labeling efficiency was $97.5{\pm}1.9%$ (n=10). 2) The dynamic images of the $^{99m}Tc-MAG_3$ were better than those of the $^{99m}Tc$-DTPA. 3) The $T_{max}(min.)$ and $T_{1/2}(min.)$ of $^{99m}Tc-MAG_3$ (n=10) were $1.5{\pm}0.5$ (left), $1.4{\pm}0.4$ (right), and $4.3{\pm}1.4$ (left), $4.8{\pm}2.0$ (right), respectively. The $T_{max}(min.)$ and $T_{1/2}(min.)$ of $^{99m}Tc$-DTPA (n=7) were $2.7{\pm}1.6$ (left), $2.7{\pm}1.6$ (right), and $3.8{\pm}1.7$ (left), $4.5{\pm}2.7$ (right), respectively. The quaility of image and labeling efficiency of the synthesized $Bz-MAG_3$ kit were excellent, that it was supposed to be used in routine clinical work.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.9
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• pp.717-722
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• 2001

This paper presents a methodology on the backward path tracking control of a trailer type robot which consists of two parts: a tractor and a trailer. It is difficult to control the motion of a trailer vehicle since its dynamics is non-holonomic. Therefore, in this paper, the modeling and parameter estimation of the system using a real-coded genetic algorithm(RCGA) is proposed and a backward path tracking control algorithm is then obtained based on the linearized model. Experimental results verify the effectiveness of the proposed method.

• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.93-100
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• 2011

Maintenance of adequate soil water potential during the period of crop growth is necessary to support optimum plant growth and yields. A better understanding of soil water movement within and below the rooting zone can facilitate optimal irrigation scheduling aimed at minimizing the adverse effects of water stress on crop growth and development and the leaching of water below the root zone which can have adverse environmental effects. The objective of this study was to evaluate the feasibility of using a portable irrigation controller with an Watermark sensor for the cultivation of drip-irrigated vegetable crops in a greenhouse. The control capability of the irrigation controller for a soil water potential of -20 kPa was evaluated under summer conditions by cultivating 45-day-old tomato plants grown in three differently textured soils (sandy loam, loam, and loamy sands). Water contents through each soil profile were continuously monitored using three Sentek probes, each consisting of three capacitance sensors at 10, 20, and 30 cm depths. Even though a repeatable cycling of soil water potential occurred for the potential treatment, the lower limit of the Watermark (about 0 kPa) obtained in this study presented a limitation of using the Watermark sensor for optimal irrigation of tomato plants where -20 kPa was used as a point for triggering irrigations. This problem might be related to the slow response time and inadequate soil-sensor interface of the Watermark sensor as compared to a porous and ceramic cup-based tensiometer with a sensitive pressure transducer. In addition, the irrigation time of 50 to 60 min at each of the irrigation operation gave a rapid drop of the potential to zero, resulting in over irrigation of tomatoes. There were differences in water content among the three different soil types under the variable rate irrigation, showing a range of water contents of 16 to 24%, 17 to 28%, and 24 to 32% for loamy sand, sandy loam, and loam soils, respectively. The greatest rate increase in water content was observed in the top of 10 cm depth of sandy loam soil within almost 60 min from the start of irrigation.

• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.162-168
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• 2011

This study was carried out to investigate the plant growth of several Carex L. plants according to light intensity and soil depth planted on a green wall and roof, and to show basic data for the use of Carex L. plants in various forms. The temperature was dropt more in the green container compared to the normal especially during the genial weather from August to September. The plant growth of Carex testaceae, Carex oshimensis Evergold, and Carex ciliatomarginata Nakai was excellent at light intensity from 0 to $1799\;{\mu}M{\cdot}m^{-2}{\cdot}s^{-1}$, and that of Carex siderosticta Hance, Carex flagellifera Bronzita, Carex ornithopoda Variegata, and Carex morrowii Ice Dance were best in lower light intensity from 0 to $786\;{\mu}M{\cdot}m^{-2}{\cdot}s^{-1}$. The leaf color of the plants changed vividly as the light intensity grew lower and the visible value of the plants increased. There must be more considerations about the pattern changes in additory experiments. The water content in the soil depth of 10 cm was maintained higher than the other treatments because of no drainage layer. Most Carex L. plants grew excellent in the soil depth of 10 cm. However, Carex oshimensis Evergold, Carex siderosticta Hance, and Carex testaceae showed the best plant growth in soil depth 20 cm, and Carex morrowii Ice Dance and Carex ciliatomarginata Nakai in soil depth of 40 cm. Therefore, Carex L. plants could be recommended as materials for green roof because they also grew well in light soil depth of 10~20 cm.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.368-370
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• 2013

투명 전극은 전기전도도를 갖는 동시에 가시광선을 투과하는 소재를 말하며, 구체적으로는 빛의 파장이 400~700 nm 영역대의 가시광선을 80% 이상 투과하며 전기전도도가 비저항으로 $10^{-3}{\Omega}cm$이하이거나 면저항이 $10^3{\Omega}$/${\Box}$소재를 의미한다. 투명 전극은 전기전도도에 따라 사용되는 용도가 다양하다. LCD, PDP, OLED 와 같은 평판디스플레이 및 3D 디스플레이의 투명전극으로 사용되는 핵심재료일 뿐만 아니라 터치스크린, 투명필름, 대전방지막, 열반사막, EMI 방지막, 태양전지 분야에 광범위하게 이용되고 있다. 일반적으로, 투명전극 박막에 가장 많이 사용되고 있는 소재는 ITO (indium tin oxide)이나, 주성분인 In의 사용량 증가로 상용 ITO 타겟 가격이 급등하고 있음으며, 고가의 ITO 타겟을 대체하기 위한 저가의 투명전극 소재 개발이 절대적으로 요구되며, 신규 소재 개발을 통한 기술력 우위 선점이 필수적으로 요구되는 상황이다. 본 연구에서는 기존에 디스플레이 분야에서 널리 활용되는 고가의 ITO를 대체하기 위한 다성분 금속산화물 투명전극 스퍼터링 타겟 제조기술을 개발하기 위한 연구로서, Metal이 첨가된 In-Ga-Zn-O기반의 3성분계 투명도전성 소재를 조성설계, 고밀도 균질 타겟 제조 및 투명전극 박막을 형성하는 연구를 실시하였다. 고체산화물 산화인듐(In2O3)분말, 산화갈륨(Ga2O3) 분말그리고 산화아연(ZnO)분말과 Metal을 몰비로 칭량한 후 분말을 폴리에틸렌제 포트에 넣고 에탄올을 충분히 채운 후 지르코니아(ZrO2) 볼(ball)을 이용하여 24 h 동안 볼 밀링(ball milling) 방법으로 혼합한 뒤, $120^{\circ}C$의 플레이트위에서 마그네틱 바로 stirring하면서 건조하였다. 이 분말을 건조기에서 완전히 건조한 후 알루미나 유발을 이용해서 pulverizing한 후 sieving기를 이용하여 분말의 조립화를 하였다. 이 분말을 금형에 넣고 300 kg/$cm^2$의 압력으로 press하여 성형한 뒤 대기중에서 소결하였다 소결을 위한 승온 온도는 $10^{\circ}C$/min이었고 소결은 $1,450^{\circ}C$에서 6 h 동안 하였다. IGZO target의 조성 비율은 1:1:12 (mol%)를 사용하였으며, 첨가한 Metal은 Boron (B), Germanium (Ge), Barium (Ba)을 사용하여 타겟을 제작하였다. M-IGZO 박막은RF magnetron Sputter를 이용하여 증착하였으며, 앞선 실험에서 제작한 타겟을 사용하여 M-IGZO박막을 투명전극으로 사용하기 위한 각각의 특성을 파악하였다. 모든 박막은 상온에서 증착을 하였으며, 증착된 박막두께를 측정하기 위해 ${\alpha}$-step IQ를 사용하였고, 광학적 특성을 분석하기 위해 UV-Visible spectrophotometer 로 투과율을 측정하였다. 그리고 전기적 특성을 측정하기 위해 Hall effect measurement 및 4-probe를 사용하였으며, 결정성 분석을 위하여 XRD를 이용하여 분석하였다. 표1은 M-IGZO타겟을 사용하여 증착시간에 따른 면저항 특성을 나타내었다. Ge, B, Ba이 첨가된 IGZO 박막은 증착시간이 증가할수록 면저항이 낮아짐을 알 수 있었다. 또한, Ge이 첨가된 IGZO 박막이 다른 금속이 첨가된 IGZO 박막의 면저항보다 현저히 낮음을 알 수 있었다. Fig. 1(a), (b), (c)는 각 타겟을 동일한 조건으로 증착을 하여 광학적특성을 나타내는 그래프이다. GZO 박막의 광학적 특성을 보면 가시광 영역에서 평균 투과율은 모두 80% 이상으로 우수한 광투과 특성을 보여 투명전자소자로 사용가능하다. 특히, 자외선 영역을 모두 차단하는 UV cut 능력이 우수함을 알 수 있었다. 따라서, 금속이 첨가된 IGZO 박막을 태양전지용 투명전극으로 사용할 경우, 자외선에 의하여 수명이 단축되는 현상을 줄여줄 수 있음을 기대할 수 있으며 내구성 향상에 크게 기여할 것으로 보인다. Fig. 2는 Ge=0, 0.5, 5%인 IGZO 투명전극을 총 40회 반복하여 증착을 실시한 후 각각의 면저항을 측정한 결과이다. 실험결과에 따르면 Ge가 0%, 5%인 IGZO 투명전극은 증착을 거듭할수록 면저항이 증가하는 결과를 나타내었으며, 0.5%인 IGZO 투명전극은 점차 안정화되어가는 결과를 나타내었다. 따라서 안정화 되었을 때 평균 면저항은 26ohm/sq.로 나타났으며, 광투과율은 Fig. 3과 같이 가시광영역에서 평균 80%이상의 결과를 보였으며, 550 nm에서는 86.36%의 우수한 특성을 나타내었다. 본 연구에서는 Metal이 첨가된 In-Ga-Zn-O기반의 3성분계 투명도전성 소재 target을 제작하여 RF magnetron sputter로 박막을 형성한 후 특성을 비교하였다. M-IGZO target 중 Ge (0.5%)을 첨가한 IGZO 타겟을 사용한 투명전극이 가장 우수한 특성을 보였으며, 제작된 M-target의 In 비율이 30% 정도로 기존의 ITO (90%) 대비하여 투명전극 제작 단가를 절감할 수 있다.