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      • KCI등재후보

        간헐식 흐름방식을 활용한 수직 · 수평 습지의 정화효율 평가

        주광진(Kwang Jin Joo),이동민(Dong Min Lee),김기중(Ki Jung Kim),조용철(Yong Chul Cho),장광현(Gwang Hyeon Jang),최이송(I Song Choi),오종민(Jong Min Oh) 응용생태공학회 2017 Ecology and resilient infrastructure Vol.4 No.3

        본 연구에서는 부영양화의 원인이 되는 질소와 인의 제거 효율을 향상시킬 목적으로 광물질을 활용한 여재를 이용하여 호기, 혐기의 흐름조건을 만들어주기 위한 수직·수평 흐름 인공습지를 고안하여 아크릴 반응조로 제작한 후 성능평가를 진행하였다. 수직·수평 흐름형 인공습지의 경우 호기 및 혐기조건을 평가하기 위해서 반응조 내 용존산소(DO) 농도를 측정해본 결과 호기상태에서는 2.7 ㎎/L, 혐기상태에서는 N.D로 확인되어 목적에 부합된 결과가 확인되었다. 실험결과에서는 SS 저감효과가 140 min, 80 min, 60 min의 운전시간에서 각각 94%, 91%, 61%의 효율을 보였고, T-P의 경우 각각의 운전시간에 따라 84%, 71%, 63%의 저감효율을 보였다. 또한 T-N의 경우 각각의 운전시간에 따라 63%, 49%, 42%의 저감효율을 보여 기존의 습지가 12~24 hr 체류시간을 가지는 것에 비하여 짧은 운전시간에도 높은 처리효율을 보이는 것으로 확인되었다. 본 연구에서는 수직·수평 흐름 방식을 복합 적용하여 기존 인공습지의 단점을 보완하기 위해 기술개발을 진행한 것으로 어떠한 기능적 효과를 갖는지 확인하였고, 향후 이에 대한 현장적용을 위한 운영 및 관리적 차원의 메커니즘 연구가 추가로 진행 될 필요가 있다. Nitrogen and phosphorus are key factors in causing eutrophication of water body. In this study, ceramics media was selected to increase the removal efficiency of nitrogen and phosphorus. We designed vertical, horizontal flow constructed wetlands to create aerobic and anaerobic flow conditions by using the media, then proceeded to performance evaluations after acrylic reactors were produced. In the case of vertical and horizontal flow constructed wetlands, we measured oxygen concentrations to evaluate aerobic and anaerobic conditions. we got the result of 2.7 ㎎/L in the aerobic condition, N.D in the anaerobic condition respectively, which suited our purpose. The result of the combined vertical and horizontal flow condition showed that the removal efficiency of SS was 94%, 91%, 61% at 140 min, 80 min, 60 min of running times, respectively, and the removal efficiency of T-P was 84%, 71%, 63% during each running time. In case of T-N, the removal efficiency was 63%, 49%, 42% during each running time. We found that the reactor exerted better removal efficiency when in the short time compared to 12 - 24 hr residence time of existing wetlands. In this study, we conducted experiments to explore functional effects after applying combined vertical and horizontal flow methods in the field. Further study will be carried out to identify its mechanism and administrative perspective.

      • KCI등재

        Fabrication of Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> Films by Rapid Thermal Annealing of Cu/ZnSn/Cu Precursor Layer and Their Application to Solar Cells

        R.B.V. Chalapathy,Gwang Sun Jung,Young Min Ko,Byung Tae Ahn,HyukSang Kwon 한국태양광발전학회 2013 Current Photovoltaic Research Vol.1 No.2

        Cu2ZnSnS4 thin film have been fabricated by rapid thermal annealing of dc-sputtered metal precursor with Cu/ZnSn/Cu stack in sulfur ambient. A CZTS film with a good uniformity was formed at 560℃ in 6 min. Cu2SnS3 and Cu3SnS4 secondary phases were present at 540°C and a trace amount of Cu2SnS3 secondary phase was present at 560℃. Single-phase large-grained CZTS film with rough surface was formed at 560ºC. Solar cell with best efficiency of 4.7% (Voc = 632 mV, jsc = 15.8 mA/cm<SUP>2</SUP>, FF = 47.13%) for an area of 0.44cm<SUP>2</SUP> was obtained for the CZTS absorber grown at 560℃ for 6 min. The existence of second phase at lower-temperature annealing and rough surface at higher-temperature annealing caused the degradation of cell performance. Also poor back contact by void formation deteriorated cell performance. The fill factor was below 0.5; it should be increased by minimizing voids at the CZTS/Mo interface. Our results suggest that CZTS absorbers can be grown by rapid thermal annealing of metallic precursors in sulfur ambient for short process times ranging in minutes.

      • D-Amphetamine이 니코틴성 흥분작용에 의한 카테콜아민 분비작용에 미치는 영향

        임건한,서유석,민선영,임지연,김용직,나광문,임동윤 朝鮮大學校 附設 醫學硏究所 2005 The Medical Journal of Chosun University Vol.30 No.1

        본 연구의 목적은 d-arphetamine이 흰쥐의 적출부신 관류모델에서 니코틴 수용체 흥분에 의한 카테콜아민(CA) 유리작용에 미치는 영향을 검색하여 그 작용기전을 규명하고자 하였다. D-amphetamine은 흰쥐 부신정맥내로 60분간 관류시 d-amphetamine자체는 약한 CA 분비작용을 나타내었으나, d-amphetamine (30 μM)을 비롯한 강력한 neuronal nicotine 수용체 작용제인 cytisine (50 μM) 및 epibatidine (30 μM)에 의한 CA 유리작용을 처음 4-10분 동안만 유의하게 증강시켰다. 또한, d-amphetamine (30 μM)은 60분간 부신정맥 내로 관류한 상태에서 dihydropyridine L-형 칼슘통로 개방약물인 Bay-K-8644 (10 μM)과 세포질내 칼슘저장고에서 Ca^(2+) ATPase 억제제인 cyclopiazonic acid (10 μM)의 CA 유리작용을 처음 4분간만 유의하게 증강시켰다. 그러나, 고농도의 d-amphetamine (500 μM)은 상기한 모든 분비촉진제의 CA분비작용을 오히려 억제하였다. 이와 같은 연구결과로 보면, 흰쥐 관류 부신수질에서 d-amphetamine은 낮은 농도에서는 콜린성 니코틴 수용체 흥분에 의한 카테콜아민 분비반응을 증강시키지만, 고농도에서는 오히려 억제적으로 작용함을 시사한다. 따라서, d-amphetamine은 용량에 따라서 흰쥐 적출 관류부신수질의 니코틴 수용체의 작용제 및 길항제로 이중 작용(dual action)을 나타내는 것으로 생각된다. 이러한 d-amphetamine의 작용은 흰쥐 부신수질 크롬친화세포의 dihydropyridine계 L-형 칼슘통로의 활성화 및 세포 내 칼슘저장고로부터 칼슘유리작용과 관련성이 있는 것으로 사료된다. The purpose of the present study was to examine the effect of d-amphetamine on CA release evoked by nocotinic receptor stimulation from the isolated perfused model of the rat adrenal gland, and to establish its mechanism of action. D-amphetamine(30 μM), when perfused into an adrenal vein of the rat adrenal gland for 60 min, enhanced the CA secretory responses evoked by ACh (5.32 mM), nicotine (30 μM), cytisine (50 μM, a selective neuronal nicotinic Nn-receptor agonist) and epibatidine (30 nM, a selective neuronal nicotinic Nn receptor agonist) only for the first period (4~10 min), although it alone has weak effect on CA secretion. Moreover, d-amphetamine (30 μM) in to an adrenal vein for 60 min also augmented the CA release evoked by BAY-K-8644, an activator of the dihydropyridine L-type Ca^(2+) channels, and cyclopiazonic acid, an inhibitor of cytoplasmic Ca^(2+) ATPase only for the first peroid (4 min). However, in the presence rather inhibited the CA secretory responses evoked by the above all of secretagogues. Taken together, these experimental results suggest that d-amphetamine at a low concentration enhances the CA secretion from the rat adrenal medulla evoked by stimulation of cholinergic nicotininc receptors, but at a high concentration it rather inhibits them. It semms that d-amphetamine has dual action acting as both agonist and antagonist at nicotinic receptors of the isolated perfused rat adrenal medulla, which are might be dependent on the concentration. It is also thought that these actions of d-amphetamine are probably relevant to the activation of the dihydropyridine L-type Ca^(2+) channels located on the rat adrenomedullary chromaffin cell membrane and release of Ca^(2+) from the cytoplasmic store.

      • KCI등재

        Fabrication of Cu<sub>2</sub>ZnSnS<sub>4</sub> Films by Rapid Thermal Annealing of Cu/ZnSn/Cu Precursor Layer and Their Application to Solar Cells

        Chalapathy, R.B.V.,Jung, Gwang Sun,Ko, Young Min,Ahn, Byung Tae,Kwon, HyukSang Korea Photovoltaic Society 2013 Current Photovoltaic Research Vol.1 No.2

        $Cu_2ZnSnS_4$ thin film have been fabricated by rapid thermal annealing of dc-sputtered metal precursor with Cu/ZnSn/Cu stack in sulfur ambient. A CZTS film with a good uniformity was formed at $560^{\circ}C$ in 6 min. $Cu_2SnS_3$ and $Cu_3SnS_4$ secondary phases were present at $540^{\circ}C$ and a trace amount of $Cu_2SnS_3$ secondary phase was present at $560^{\circ}C$. Single-phase large-grained CZTS film with rough surface was formed at $560^{\circ}C$. Solar cell with best efficiency of 4.7% ($V_{oc}=632mV$, $j_{sc}=15.8mA/cm^2$, FF = 47.13%) for an area of $0.44cm^2$ was obtained for the CZTS absorber grown at $560^{\circ}C$ for 6 min. The existence of second phase at lower-temperature annealing and rough surface at higher-temperature annealing caused the degradation of cell performance. Also poor back contact by void formation deteriorated cell performance. The fill factor was below 0.5; it should be increased by minimizing voids at the CZTS/Mo interface. Our results suggest that CZTS absorbers can be grown by rapid thermal annealing of metallic precursors in sulfur ambient for short process times ranging in minutes.

      • 건강증진 프로그램이 노인의 혈중지질수준에 미치는 영향

        민춘기,염동삼,현광석 忠南大學校體育科學硏究所 2001 體育科學硏究誌 Vol.19 No.1

        The Purpose of this study was to investigate the effects of program for improving blood lipid level. This study employed 36 healthy older people who were 60∼65 years old(mean age 62.5years). The subjects were randomly assigned to one of three groups (two experimental groups and one control). Each group ended up with 12 subjects. The subjects in the utilized the 3×4 factorial ANOVA repeated measure design. The results of the study were as follows: 1. There were statistically significant difference between the HDL-C means of the control group and the two experimental groups. 2. The total cholesterol(TC), triglyceride(TG) are meaned among the control group and the experimental groups show statistically significant differences.

      • 혈우병 환자에 동반된 자발성 후복막강 출혈

        김광일,김동호,우상민,이석주,김홍성,조인성,윤환중,조덕연,김삼용 충남대학교 의과대학 지역사회의학연구소 1997 충남의대잡지 Vol.24 No.1

        Spontaneous retroperitoneal hemorrhage due to hemophilia A with impaired coagulopathy is very rare. Spontaneous retroperitoneal hemorrhage has been recorded as having originated from many retroperitoneal organs and blood vessels, and it may be due to local and/or systemic factors. In the majority of the patients, kidney and adrenal gland were the major site of hemorrhage. The systemic causes of spontaneous retroperitoneal hemorrhage are anticoagulation therapy and chronic hemodialysis. During the course of these treatments, hemorrhagic complications may occur at many site, including the retroperitoneal space. Blood dyscrasias including leukemia, polycythemia, sickle cell trait and hemophilia have been reported associated with spontaneous retroperitoneal hemorrhage. We report a case of spontaneous retroperitoneal hemorrhage occurred in a gemophilia A patient with brief review of literature

      • 단감 저장병 원인균 푸른 곰팡이 분리 보고

        안광환,배영민,김동완,주우홍 Institute of Genetic Engineering Changwon National 2002 Gene and Protein Vol.6 No.-

        To develop the control method of postharvest disease on persimmons, the analysis of a major pathogen of postharvest disease and incidence of the disease on persimmon fruits were studied from 2001 to 2002. A major postharvest pathogen was identified on the basis of morpholoical characteristics as Peniacillium sp..

      • 수익관리를 위한 항공요금체계 모델에 관한 연구

        이광원,정민의 천안대학교 2002 천안외국어대학논문집 Vol.- No.2

        Airline fares are based on demand. When setting fares, airlines take into consideration variables like the number of passengers in a particular market, passenger income level, competitors' prices and related travel expenses, passenger preferences and passenger expectations with respect to future travel. The major objective of the airlines is to maximize revenue from each flight by offering the right mix of full and low fares. Many airlines have developed yield management computer system that allocate the right mix of seats for the right price. Each Airline fare is designated a “fare basis” that is composed of a combination of letters and figure. This indicates the seat availability for the specific fare on every flight. This article is tried to study yield management of airfare and understand the optimal allocation of available seat to different classes under the airfare counting strategy. Especially EMAR model can be applied to the multi-class estimations with the objective of maximizing total expected revenue. And then airfare models for Yield management are critical to reaching financial success in the airline industry. And they are called economies of scope rather than economies of scale. They are arisen from factors like the control of distribution, price leadership, loyalty marketing schemes and frequent flyer programmes.

      • KCI등재

        12Cr 강의 화염경화 표면처리 층의 초음속 물방울 충격에 의한 손상 거동

        김광호,이민구,김경호,김흥회,김길무 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.1

        Water drop impact erosion properties of the 12Cr steel, currently used as nuclear steam turbine blade material, surface-hardened by the flame hardening process have been characterized. For this, variations of both the maximum erosion depth de,,,,ax and volume loss V with the cumulative impacts n at the supersonic impact velocity (~350 m/s) have been investigated for the as-received and flame-hardened 12Cr steels with different hardnesses. Typically all the samples showed an erosion-time characteristic involving the incubation period initially followed by the steady state period. It is also found that the d_(e,max) increases stepwise-like with the number of impacts n, which results from a sudden formation of craters by crack propagation. Compared to those for the as-received 12Cr steel, the flame-hardened ones showed an excellent resistance to water drop impact erosion with 2.2~2.8 times higher incubation time n, and 115~1/8 times lower erosion rate a. In the incubation period the as-received 12Cr steel was damaged by ductile depression and ploughing, while the flame-hardened 12Cr steel by fatigue cracks and brittle platelet deformation. Erosion in the steady state period was developed by the cleavage fracture commonly. (Received July 22, 2004)

      • KCI등재

        증기 터빈 동익 재료인 12Cr 강의 화염표면 처리에 의한 열 이력 제어 및 경화 특성에 관한 연구

        이민구,김광호,김경호,김흥회 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.11

        Low carbon 12Cr steel used as a nuclear steam turbine blade material have been surface-modified by the flame hardening process and the properties of hardness, hardening depth, and residual stress have been studied. For this, the thermal cycles of 12Cr steel have been controlled precisely as a function of the surface temperature, the exposed height from the water surface, and the cooling rate. The application of flame hardening increases the hardness of 12Cr steel (base value, 250 HV) to 420~550 HV considerably, forming relatively sharp hardening boundaries. Both the hardening depth and the austenitization period are linearly correlated well within the range of processing conditions employed. The rapid cooling rate also increases the hardening depth as well as the surface hardness. The properties of residual stress are discussed in terms of contributions of both the thermal and transformation stress components. The optimum processing conditions for the desirable residual stress state in the material are as follows : less than 1200℃ for the 18 mm-exposed and less than 1150℃ for full-exposed conditions by the criteria of Siemens AG-KWU, and on the basis of the specification of GE Power Generation Engineering, 944~1050℃ for the 10 mm-exposed, 883~1150℃ for the 14 mm-exposed, 833~1134℃ for the 18 mm-exposed, and 785~1097℃ for the full-exposed.

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