• Economic and Environmental Geology
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• v.39 no.5 s.180
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• pp.525-535
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• 2006

A study on stream-groundwater exchange was performed using head and temperature data of stream water, streambed, and groundwater. Groundwater level and temperature were obtained from multi-depth monitoring wells in small-scale watershed. During the summer and winter season, time series of temperature data at streambed and groundwater were monitored for six months. In the winter time, we measured the temperature gradient between stream water and streambed. The observed data showed three typical types of temperature characteristics. First, the temperature of streambed was lower than that of stream water; second, the temperature of streambed and stream water was similar; and the last, the temperature of streambed was higher than that of stream water. The interconnections between the stream and the streambed were not homogeneously distributed due to weakly developed sediments and heterogeneous bedrock exposed as bed of the stream. The temperature data may be used in formal solutions of the inverse problems to estimate groundwater flow and hydraulic conductivity.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.1
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• pp.6-14
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• 2011

The re-crystallization process for recovering granular crystalline gypsum from phospho-gypsum have proposed. The process consists of two stages; at the first stage, needle-like fine gypsum is recovered with under-product of 325 mesh wet screening after the speedy hydration of dehydrated phospho-gypsum, and at the second stage, granular crystalline gypsum is recovered with upper-product of 325 mesh wet screening after dehydration and re-crystallization of the needle-like fine gypsum in $Na_2SO_4$ solution. This paper is mainly focused on the influence of dehydration time, cooling speed of temperature and re-crystallization temperature on the recovery of granular crystalline gypsum. And the re-crystallization velocity of needle-like fine gypsum at room temperature and the variation of $Ca^{2+}$ concentration of gypsum slurry during over all re-crystallization process were also discussed.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.69-76
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• 2016

Current driving capability of MCT (MOS Controlled Thyristor) is determined by turn-off capability of conducting current, that is off-FET performance of MCT. On the other hand, having a good turn-on characteristics, including high peak anode current ($I_{peak}$) and rate of change of current (di/dt), is essential for pulsed power system which is one of major application field of MCTs. To satisfy above two requirements, careful control of on/off-FET performance is required. However, triple diffusion and several oxidation processes change surface doping profile and make it hard to control threshold voltage ($V_{th}$) of on/off-FET. In this paper, we have demonstrated the effect of $V_{th}$ adjustment ion implantation on the performance of MCT. The fabricated MCTs (active area = $0.465mm^2$) show forward voltage drop ($V_F$) of 1.25 V at $100A/cm^2$ and Ipeak of 290 A and di/dt of $5.8kA/{\mu}s$ at $V_A=800V$. While these characteristics are unaltered by $V_{th}$ adjustment ion implantation, the turn-off gate voltage is reduced from -3.5 V to -1.6 V for conducting current of $100A/cm^2$ when the $V_{th}$ adjustment ion implantation is carried out. This demonstrates that the current driving capability is enhanced without degradation of forward conduction and turn-on switching characteristics.

• KSBB Journal
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• v.19 no.1
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• pp.83-87
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• 2004

This research was designed to investigate the effects of Estromon including FGF271 (Female Growth Factor 271) which was developed as a phytoestrogen for post- and pre-menopausal syndrome (PMS). The oral administration of two capsules of Estromon twice a day for 3 months significantly improved PMS (Post-/Premenopausal Syndrome) about 5 times more than placebo group (OR=5.04, 95% C.1. 1.40-18.14). In the group of 24 patients having taken Estromon, the concentration of alkaline phosphatase asn the bone marker decreased by -9.3${\pm}$9.5 IU/L after 3 months with a statistic significance. Since the concentration of osteocalcin as the other bone marker also decreased in more patients in Estromon group than in placebo group, the bone density might be expected to be improved in long-term treatment. Serum human growth hormone level increased in 17 out of 24 patients. Triglycerides decreased by -8.0${\pm}$40 (mg%) after 1 month and by -4.4${\pm}$36 (mg%) after 3 months in Estomon group while triglycerides increased in both cases in placebo group (p.0.01). Therefore, PMS patients might benefit from Estromon as a phytoestrogen supplement without any serious side effects.

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.2
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• pp.227-235
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• 1993

This study was carried out to evaluate the possibility of composting for organic solid waste from restaurants and domestics. Small three vessels were prepared which were conditioned to semianaerobic, convectional and air-blowed type. During the experiment period for 4 months, the values of volatile solid(VS) %, moisture % and carbon/nitrogen (C/N) ratio of the wastes in the vessels were stabilized, 80 % to 40-50 %, 80 % to 48-55 % and 18 to 8-10, respectively. On the basis of VS % and C/N ratio, the reactions were more adaptable to 2nd order formula than to 1st order one, Reaction rate constant of the 3 vessels were estimated, $4.96{\times}10^{-5}(day^{-1})$ in the semianaerobic type, $5.82{\times}10^{-5}(day^{-1})$ in the convectional type and $8.42{\times}10^{-5}(day^{-1})$ in the air-blowed type on VS. Compared reaction rate constants(k), it can be said that composting period shorten if air is supplied artificially and that vessels simular to those of this study are useful for household organic waste at the backyards.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.47-47
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• 2011

하도 내 수역이 식생으로의 천이가 진행되고 최종적으로는 육상 식물들이 활착하게 되는 육역화 현상은 하도의 수리학적 문제 및 환경생태적 측면에서 큰 문제를 발생시킬 가능성을 내포하고 있다. 최근 하천복원의 필요성이 강조됨에 따라 물골공법 및 국부세굴 유도형 공법 등 실용성을 포함시킨 다양한 하천 복원공법이 제시되고 있다. 물골공법은 자연적인 물골형상에 의한 유사퇴적방지, 홍수시 유속저감 및 생물서식처를 조성하는 하상 생태복원 공법을 의미하며, 본 연구에서는 수리모형실험 및 3차원 수치모의를 이용하여 다양한 하도육역화 방지 공법 중 물골공법의 효과 및 적용성을 검토하였다. 물골공법의 특성 중 유사퇴적방지의 효율성 분석을 위해 부정류(unsteady state)상태에 대해 연구를 수행하였으며 홍수 이후 수위하강시 고수부지 및 물골 주변에서의 흐름특성을 재현하였다. 수위하강 모의를 위해 임의의 수위하강시간을 선정하여, 수위하강이 진행되는 시간( )을 각각의 수위하강시간으로 무차원 화한 후 무차원된 시간(t/�� )에 따른 흐름특성을 비교 분석하였으며 모의 및 분석결과, 수위하강시간이 80초 이상일 경우 주요 지점에서의 유속의 변화는 무차원된 시간에 대하여 일치하였으며 수리모형실험 및 수치모의에 적용할 수위하강시간으로 선정할 수 있었다. 물골 전구간에 대한 부정류 실험을 위해 LSPIV(Large-Scale Particle Image Velocimetry)장치를 이용하여 수위하강에 따른 물골주변의 흐름특성을 관측하였으며 3차원 수치모의를 통해 검증하였다. 실험 분석결과, 수위하강에 따라 고수부지 위로 흐르는 유수가 물골 내부로 유입되어 물골을 따라 흘러 물골 합류부로 이동하는 것으로 나타났으며, 이는 홍수시 유수와 함께 떠다니는 부유사(suspended load)가 물골로 유입되어 물골 합류부로 이동하므로 물골의 유사배제 가능성을 판단할 수 있었다. 또한 물골의 유사배제능력을 평가를 위해 실험을 통하여 산정된 최대 및 최소 마찰속도(U )와 유사이동 한계곡선을 이용하여 물골의 통한 배제 가능한 유사의 입경을 분석하였다. 분석결과, 최소 2mm에서 최대 4mm로 나타났으며 이 입경 이하인 유사에 대해서는 퇴적되지 않고 물골을 통하여 배제될 수 있을 것으로 예상되었다. 본 연구 결과 물골공법 적용시 수위하강에 따라 물골에서 하도방향으로 유사의 수세(flushing)효과가 나타났으며 유사의 부상 및 이송이 효과적으로 발생하여 고수부지 내 유사퇴적 방지가 효과적인 것으로 판단되었다. 추후 다양한 형상의 물골에 대한 능력검토가 보완된다면 물골설계지침 제안을 위한 자료로 활용 가능할 것이다.

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.309-313
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• 2012

The purpose of this study is to simultaneously detect and identify specific genus of Lactobacillus distributed in vagina of healthy women in their twenties by using multiplex primer. Vaginal fluid samples were taken from 166 women who were healthy and did not have vaginosis symptoms caused by bacterial infection. Six species of lactic acid bacteria belong to Lactobacillus genus that are known to inhabit in healthy vagina were selected to make a species-specific multiplex primer. Multiplex primer I was specified to selectively detect L. iners, L. crispatus, L. gasseri and multiplex primer II was specified to selectively detect L. acidophilus, L. jensenii, L. fermentum. L. crispatus (77%) was most frequently detected, and L. acidophilus (57%) and L. jensenii (57%) were relatively higher than others. Although the proportion of L. iners (59%) was a little higher than those of L. acidophilus and L. jensenii, this should be further validated in healthy women's vagina to be sure since they often appear in women having bacterial vaginosis and/or during the antibiotic therapy. Conclusively, the multiplex PCR technique using the species-specific primer could a useful tool to predict variation of vaginal health condition and process of recovery from vaginal disease.

• The KIPS Transactions:PartD
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• v.13D no.6 s.109
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• pp.775-788
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• 2006

Many disaster monitoring systems are constantly studied to prevent disasters such as environmental pollution, the breaking of a tunnel and a building, flooding, storm earthquake according to the progress of wireless telecommunication, the miniaturization of terminal devices, and the spread of sensor network. A disaster monitoring system can extract information of a remote place, process sensor data with rules to recognize disaster situation, and provide work for preventing disaster. However existing monitoring systems are not enough to predict and prevent disaster, because they can only process current sensor data through utilizing simple aggregation function and operators. In this paper, we design and implement a disaster prevention system to predict near future dangerous area through using outside sensor network and spatial Information. The provided prediction technique considers the change of spatial information over time with current sensor data, and indicates the place that could be dangerous in near future. The system can recognize which place would be dangerous and prepare the disaster prevention. Therefore, damage of disaster and cost of recovery would be reduced. The provided disaster prevention system and prediction technique could be applied to various disaster prevention systems and be utilized for preventing disaster and reducing damages.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.201-207
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• 1979

The stow net now used in the Yellow Sea, are traditional bag net with the opening held by a lighter upper and a weighted lower beams standing against the current. Such bag net anchored at the bottom are known in many countries, particularly in the estuaries of large rivers, but more rarely in sea fisheries, because they are too much affected by the weather, moreover a permanent strong current is necessary. Some scientists intended to improve this fishing gear, using the shearing devices instead of a lighter upper and a weighted lower beams in order to widen mouth of the stow net however they are unsuccessful. One-fortieth scale model net of the stow net was tested in a circular water tank with an effective volume of $5.67m\times1.76m\times1.00m$ of observing the configuration and tension of the net. Experiments were carried out under the various combination including water velocity, spherical floats and elevating floats with the shearing hoods instead of the upper beam. We found those devices offered a very low resistance per net area to current compared with the spherical floats or upper beam, and had a fairly good shearing power at any velocity and direction of the current. The total resistance (R) of the model net to which shearing hoods and floats are attached can be induced by the following formula under the condition of 0.25m/sec to 0.5m/sec, $$R(kg)=3.11V^{1.54}$$ The height (h) of the improved model net (m-B) is higher than traditional model net(m-A) with upper and lower beams, m-A: h(cm)=89.22-2.42(V-15). $V\geqq15,\;cm/sec$ m-B: h(cm)=89.20-0.78V (V:cm/sec) The catch efficiency of improved model net is 1.5 times traditional model net.

• Journal of the Korean Wood Science and Technology
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• v.41 no.6
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• pp.515-527
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• 2013

Building energy simulations which are mainly used in Korea have evaluated the building energy performance with the different thermal conductivity of construction materials. In order to evaluate the energy consumption accurately, the difference in thermal conductivity of the wood used in stud for wooden structure was confirmed from the each simulation. In addition, the thermal transmission of building members and the thermal bridge at the conjunction of building members according to thermal conductivity from each simulation programs were researched. The thermal conductivity of pine that has the largest variation among the energy simulations was applied to the thermal properties of studs in wooden structure. The maximum error between the maximum and minimum thermal transmission of roof, wall, and floor slab was $0.023W/m^2{\cdot}K$. Plus, that thermal bridge at Rafter junction on the roof, roof-wall joint, and floor slab-wall joint was $0.025W/m{\cdot}K$. The heat transfer image for changes in temperature and the heat exchange were analyzed by HEAT2 program. The distorted temperature lines were found around the insufficient insulated connection parts. It was predicted that the temperature at the distorted parts in the analyzed image was lower than that of the other portion of the other structures.