3상 전압형 PWM 컨버터의 전류제어

우정인,고성현,진해중,허태원 東亞大學校 附設 情報通信硏究所 1998 情報通信硏究所論文誌 Vol.6 No.1

This paper presents a novel current control system in order to eliminate the steady state control error for three-phase voltage source PWM converters. A general mathematical model of the converter which is represented as a state-space model is estabblish. The state-space model is used for simulations of the converter with the proposed tracking control system of sinusoidal current. In this system, a novel current control which do not require coordiante transformations using internal principle of PI controller is described. It is iproved that the steady state deviation reduce to zero from the transfer function fo source current control system. Finally, simulations show good source current control characteristics by means of the simplified control algorithm which do not require coordinate transformations.

분변토 첨가에 따른 토양중의 파라치온의 거동

허창두,신남철,우성훈,박승조 東亞大學校 附設 環境問題硏究所 2004 硏究報告 Vol.26 No.-

The aim of this study was investigated with the behavior of parathion adsorption and degradation efficiency of parathion in various samples loaded with earthworm casting. Adsorption capacity of parathion in loam soil was better than clay loam. Degradation of parathion was 70 percent in loam and clay loam soil to time but samples was loaded 5% casting, L0C5 and CLC5 had shown 90 percent degradation. We found that parathion was leachers pesticide as groundwater ubiquity score (GUS) was more than 4.0.

동해안 석호의 육수학적 조사(1): 청초호

허우명,이상균,권상용,김동진,김범철 江原大學校 附設 環境硏究所 2001 環境硏究 Vol.18 No.-

Water quality and pollution state of Lake Chungcho were evaluated during three years from 1998 to 2000. We surveyed physicochemical parameters, and TSI(trophic state index) was calculated using TP, Chl. a, and SD(secchi disc transparency) data of growing season average. Water samples were collected bimonthly except freezing season. During the study period, total annual precipitation in 1998, 1999 and 2000 year was 1,797, 1,722 and 1,345 mm, respectively. Salinity and conductivity were high (29.3±5.5 ppt, and 45,105±7,585 μS/cm) then other lagoons in the Eastern Coast of Korea. Chemocline was formed by salinity at 0.5~1.5m water depth. As a result of this, DO concentration of hypolimnion was below 3.0 mgO₂/L. Especially, when intense chemocline was formed, temperature of hypolimnion was higher than epilimnion. Secchi disc transparency, chlorophyll a, and COD were 0.8±0.3m, 15.7±20.7 mg/㎥, and 3.1±0.8 mgO₂/L, respecively. Most of TN/TP ratios below 20, but concentration of TN and TP was high. Values of TSI ranged between 59 and 77, indicating a eutrophic condition in this system.

사마귀류 추출물의 생물학적 활성 비교

허진철,황재삼,강석우,윤치영,이상한 慶北大學校農業科學技術硏究所 2007 慶北大農學誌 Vol.25 No.-

In order to investigate the availability of insect resources for agrobiotechnological or medical purposes, we examined antioxidant (DPPH and FRAP assay) and cell viability by oxidant stress and NO inhibition assay by treatment of the extracts of Statilia maculata Thunberg, Tenodera angustipennis Saussure and Tenodera aridifolia Stoll. We found that Tenodera angustipennis Saussure and Tenodera aridifolia Stoll extract (DW, etanol, methanol) had high levels of anti-oxidant activity, whereas Tenodera aridifolia Stoll extract showed increased cell viability by hydrogen peroxide and inhibition of NO production. These findings suggest that Statilia maculata Thunberg, Tenodera angustipennis Saussure and Tenodera aridifolia Stoll, extract have potentials to be developed for agrobiotechnology or medicinal use, indicating that mechanistic study including inhibition against molecular inflammation will show a possibility for the development of useful insect resources.

도암호의 수질과 어류군집 특성 연구

이상하,최재석,이광열,장영수,임인수,허우명,김재구,김범철 강원대학교 부속 환경연구소 2005 Journal of the Environment Vol.2 No.-

To investigate nutrient dynamics of the lake and fish community, both water and fish samples were collected at three different areas (dam site, upper inflowing and downstream of lake outfow) for one year from Sep.2004 to Aug.2005 During the experimental periods, mean concentration of chl, a in epilimnetic layer (0-5m) was 18.5mg^(-3) and transparency ranged from 0.3m to 2.4m, respectively. In nutrient, mean concentrations of TP and TN were 111 mgP m^(-3) and 4.4 mgN L^(-1), respectively. Based on the water quality standard suggested by U.S.EPA(*1976), the trophic state of Lake Doam was classified as eutrophic state. Total number of fish collected in Lake Doam was 9,600 indiveduals in 26 species of 6 family. Sixteen of Korean endemic soecies including H. mylodon, A. signifer, P. tenuicorpa occurred. O. mykiss as introduced fish was also found in Lake Doam. Dominant and subdominant species were P. herzi and Z. platypus that took about 34.6% and 22.5% of total fish composition, respectively. Six species including A. signifer. P. tenuicorpa. and R. kumgangensis were rare in Lake Doam. Pelagic typw of figh commonly occurred at upper regions, whereas benthic type was mainly domenated at downstream area. Therefore, pollution source inflowed from the upper regions did not seriously affect downstream area (Songcheon water system) due to the role of dam as pollutant barrier. In addition high appearance of Comat type of fish that si hybrid between gold fish (C.auratus) and C. auratus was found in the lake, It was unclear the reasons that high prorortion of mutant species apperared in the lake. Further more researches are required in this area.

Thermally Stable Intermolecular Proton Bonds in Polyaromatic Aldehyde Crystals

Heo, Sung Woo,Hwang, In-Chul,Chun, Young,Lee, Jung Woo,Singh, N. Jiten,Kim, Seung Bin,Kim, Kwang S. Wiley Blackwell (John Wiley Sons) 2011 Chemistry - An Asian Journal Vol.6 No.8

Larvae and juvenile of Acanthaphritis unoorum (Percophidae, Pisces), new to Korean fish fauna

Sung-Hyun Heo,Tae Woo Ban,Jin-Koo Kim,Hwang-Sung Ji,Seong Yong Moon 한국수산해양기술학회(구 한국어업기술학회) 2018 한국수산해양기술학회 학술발표대회 Vol.2018 No.11

전방 경유 디스크 절제술 및 유합술과 후방 추간공 절제술에서의 경추 추간공의 형태학적 변화 비교

정성수(Sung-Soo Chung),선우성(Woo-Sung Sun),정종철(Jong-Chul Chung),허기성(Ki-Sung Heo),김현민(Hyun-Min Kim) 대한정형외과학회 2021 대한정형외과학회지 Vol.56 No.6

목적: 경추 추간공 협착증에서 전방경유 경추 추간판 절제술 및 유합술과 추간공 절제술 후 추간공의 크기 변화 및 임상 결과를 비교하여 그 효용성에 대하여 알아보고자 하였다. 대상 및 방법: 2018년 1월부터 2019년 3월까지 전방경유 경추 추간판 절제술 및 유합술 및 추간공 절제술을 시행한 186명 중에서 나이, 성별, 체질량지수 등을 고려한 환자-대조군 연구를 통해 선별된 102예를 대상으로 하여 후향적으로 분석하였다. 술 전 및 술후 5일째 자기공명영상을 촬영하여 전방경유 경추 추간판 절제술 및 유합술을 시행 받은 군(A군-51명)과 추간공 절제술을 시행 받은 군(B군-51명) 사이의 추간공의 크기 변화 및 임상 결과를 비교하였다. 결과: 술 후 A군에서 추간공 수직 직경의 변화는 평균 1.7 mm, B군에서는 평균 1.2 mm로 증가하였으며 A군에서 0.5 mm 높게 나타났다(p=0.042). 추간공 횡단 직경의 변화는 A군에서 평균 1.2 mm, B군에서는 1.8 mm로 B군에서 0.6 mm 넓게 나타났다(p=0.021). Neck disability index (NDI), Japanese orthopaedic association (JOA) score 모두 양 군에서 호전되는 결과를 보였으며 A군에서 더 높은 호전을 보였지만 통계학적으로 유의하지는 않았다(각각 p=0.356, p=0.607). 결론: 미세현미경과 내시경을 이용한 추간공 절제술은 전방경유 경추 추간판 절제술 및 유합술에 필적하는 임상적 결과를 보였고, 수술 후 경부의 통증 및 불편감을 줄이면서 인접분절의 퇴행변화를 줄일 수 있기 때문에 경추의 추간공 협착증 환자에서 유용한 치료 방법 중 하나로 판단된다. Purpose: This study compared the change in foraminal space on magnetic resonance imaging (MRI) and the clinical outcome after anterior cervical discectomy and fusion (ACDF) versus foraminotomy in cervical foraminal stenosis. Materials and Methods: A retrospective case-control study was conducted from January 2018 to March 2019 on 186 patients who underwent ACDF and foraminotomy. One hundred and two cases were selected considering age, sex, and body mass index. MRI was performed before and on the 5<SUP>th</SUP> day after surgery to compare the changes in the foraminal diameter between the ACDF group (group A-51) and foraminotomy group (group B-51). Results: Between groups A and B, the average change in foraminal vertical diameter was 1.7 mm and 1.2 mm, respectively; group A was 0.5 mm larger difference (p=0.042). The average change in foraminal transverse diameter was 1.2 mm and 1.8mm, respectively; group B showed a 0.6 mm larger change (p=0.21). Both the neck disability index (NDI) and Japanese orthopaedic association (JOA) scores improved in both groups. Group A showed more improvement, but there was no significant difference (p=0.356, p=0.607, respectively). Conclusion: Foraminotomy is a useful option for patients with foraminal stenosis of the cervical spine because it showed comparable clinical and morphological results to ACDF and could minimize motion segment loss and muscle and ligament damage.

반전유화법에 의한 유화아스팔트의 안정성 연구

허우성 ( Woo Sung Heo ),이은경 ( Eun Kyoung Lee ),최세영 ( Sei Young Choi ) 한국고무학회 2009 엘라스토머 및 콤포지트 Vol.44 No.2

본 연구에서는 아스팔트가 가지는 단점을 보완하고자 아스팔트를 비이온 계면활성제(Span 80, Span 60, Tween 80, 및 Tween 60), 음이온 계면활성제(SLS), 및 양이온 계면활성제(Imidazole)를 변량 배합하여 반전유화법으로 아스팔트 에멀젼을 제조하였다. 유화아스팔트의 안정성을 규명하고자 입자크기, 점도, 제타전위, 및 내수성을 고찰하였다. 비이온 계면활성제와 음이온 계면활성제를 혼합 사용할 경우 유화아스팔트의 안정성은 우수하였으며 계면활성제의 양이 증가함에 따라 입자크기는 감소하였고, 반면에 점도와 제타전위 및 내수성은 증가하였다. In this study, asphalt emulsion was manufactured by phase inversion emulsification method with nonionic surfactants(Span 80, Span 60, Tween 80, and Tween 60), anionic surfactant(SLS) and cationic surfactant(Imidazole) in different feeding ratio to make up for the week points of asphalt. Its stabilization was carefully investigated with respect to droplet size, viscosity, zeta potential, and water-proofing property. When the surfactants mixed with nonionic and anionic surfactant were used into the asphalt, a stabilization of the asphalt emulsion was good. As the amount of the mixed surfactant was increased, the droplet size of asphalt emulsion were decreased, while the viscosity and zeta potential were increased. When the surfactants mixed with nonionic and anionic surfactant were used into the asphalt, a stabilization of asphalt emulsion was good.

500㎿ Retrofit 터빈 로터 열전달 및 응력해석에 관한 연구

최우성(Woo Sung Choi),장성호(Sung Ho Chang),송기욱(Gee Wook Song),김범신(Bum Shin Kim),허재실(Jae Sil Heo) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.5