중등학교 교과서의 농업·농촌 기능 분석 및 반영 방안

서우석,강대구,정진수,김절용,김재호,이윤조 한국농업교육학회 2007 농업교육과 인적자원개발 Vol.39 No.2

태양광 발전시스템의 최대전력추적을 위한 DC/DC 컨버터 제어

최연옥,서진연,장용해,정삼용,조금배 조선대학교 에너지.자원신기술연구소 1999 에너지·자원신기술연구소 논문지 Vol.21 No.2

Solar energy converters were used to convert the electrical energy from the solar arrays to a stable and reliable power source. The object of this paper is to analyze and design DC/DC converters of different types in a solar energy system in order to investigate the performance of the converters. A simple method which combines a discrete time control and a PI compensator is used to track the maximum power point of the solar array. The system is kept to operate close to MPPT's thus the maximum possible power transfer from the solar array is achieved. Experimental tests were carried out for buck, boost and buck-boost converters using a simple maximum power point tracking algorithm.

치조골 상실에 따른 상악 치아군 저항중심의 변화에 관한 유한요소해석

성상진,김인태,국윤아,전윤식,김성훈,모성서 대한치과교정학회 2009 대한치과교정학회지 Vol.39 No.5

효과적인 교정치료계획의 수립을 위하여 치열군의 저항중심의 위치에 대한 평가는 필수적이다. 이번 연구의 목적은 상악 치열군(4전치, 6전치, 14치아)에서 치조골 손실에 따른 저항중심의 위치변화를 조사해보고자 하였다. 상악 전치열 14개 치아와 치주인대 및 0 mm, 2 mm, 4 mm 손실된 치조골의 3차원 유한요소 모델을 제작하였고 각 치아군(4전치, 6전치, 14치아)별로 치관부를 협측, 설측호선 및 splint wire로 고정하여 치아군 모델을 제작한 후 상악 중절치의 절단연 중점에서 연장된 splint wire에 4전치와 6전치군에는 200 g, 14치아군에는 400 g의 후방 견인력과 압하력을 적용하여 저항중심의 수직적, 수평적 위치를 분석하였다. 4전치군에서 저항중심의 수직 위치는 치조골 0 mm, 2 mm, 4 mm 손실에 따라 중절치의 절단연에서 치근방향 13.5 mm, 14.5 mm, 15 mm, 수평 위치는 후방 12 mm, 12 mm, 12.5 mm, 6전치군에서는 치근방향 13.5 mm, 14.5 mm, 15.5 mm, 후방 14 mm, 14 mm, 14.5 mm, 14치아군에서는 치근방향 11 mm, 13 mm, 14.5 mm, 후방 26.5 mm, 27 mm, 25.5 mm에 위치하였다. 모든 치아군에서 저항중심은 치조골 손실에 따라 치근첨 방향으로 이동하였으나, 치조정과의 거리는 가까워졌고, 4전치군과 6전치군에서 저항중심은 치조골 손실에 따라 후방으로 이동하였으나, 14치아군에서는 치조골 2 mm 손실 시에는 후방으로 이동하였으나, 4 mm 손실 시에는 전방으로 이동하였다. Objective: The aim of this study was to investigate the changes in the center of resistance of the maxillary teeth in relation to alveolar bone loss. Methods: A finite element model, which included the upper dentition and periodontal ligament, was designed according to the amount of bone loss (0 mm, 2 mm, 4 mm). The teeth in each group were fixed with buccal and lingual arch wires and splint wires. Retraction and intrusion forces of 200 g for 4 and 6 anterior teeth groups and 400 g for the full dentition group were applied. Results: The centers of resistance were at 13.5 mm, 14.5 mm, 15 mm apical and 12 mm, 12 mm, 12.5 mm posterior in the 4 incisor group; 13.5 mm, 14.5 mm, 15 mm apical and 14 mm, 14 mm, 14.5 mm posterior in the 6 anterior teeth group; and 11 mm, 13 mm, 14.5 mm apical and 26.5 mm, 27 mm, 25.5 mm posterior in the full dentition group respectively according to 0 mm, 2 mm, 4 mm bone loss. Conclusions: The center of resistance shifted apically and posteriorly as alveolar bone loss increased in 4 and 6 anterior teeth groups. However, in the full dentition group, the center of resistance shifted apically and anteriorly in the 4 mm bone loss model.

단순추적법에 의한 태양전지의 특성평가

최연옥,서진연,조금배 조선대학교 에너지.자원신기술연구소 1997 에너지·자원신기술연구소 논문지 Vol.19 No.2

The main problems in photovoltaic performance measurement arises from the fact that solar cells have a highly selective spectral response and are, therefore, very sensitive to the spectral composition of the incident radiation. Outdoors, this varies considerably with location, weather, time of year and time of day, Indoors, it depends on the type of simulator used and it can change as the equipment ages. Unless measurement procedures take account of these variations and other difficulties, such as the marked temperature dependence of solar cell, the results can be grossly erroneous. Performance rakings of the same module by laboratory have been know to disagree by as much as 20%.

산유체모델에 의한 Building downwash 현상 해석

구윤서,최상민,이진호,윤희영 안양대학교 산업기술연구소 2000 自然科學硏究 Vol.7 No.-

본 연구에서는 굴뚝주변에 위치한 건물에 의한 세류현상을 보다 정확히 모사하기 위해서 전산유체모델을 이용하였다. 계산 신뢰도를 검증하기 위해서 전산모델 계산치와 1993년 Thompson의 추적자 실험에 의한 실측치 및 대기 환경영향평가에 많이 사용되는 ISCST3 모델 계산치와 각각 비교하였다. ISCST3에서는 건물의 영향을 고려하기 위하여 BPIP을 이용, 건물의 높이와 폭을 결정하여 모델링을 수행하였다. 전산유체모델에서는 건물을 형상화시키고 굴뚝에서 오염물질을 배출시켜 확산 계산을 하였다. 전산유체모델로 모사한 결과, 건물의 후면에 wake가 발생하는 것을 볼 수 있었고, wake zone의 길이는 건물 높이의 약 2배가 되었다. 오염물질 농도를 비교한 결과 ISCST에서는 최대 농도값과 착지점이 일치하지 않았으나, 전산유체모델로 계산한 결과는 추적자 실험치와 거의 일치한 값을 나타냈다. This study used the computational fluid dynamic(CFD) for describing a dispersion influenced by building downwash. We compared calculated concentrations with Thompson's tracer experiment and ISCST3 models. In calculating ISCST3 model, BPIP(Building Profile Input Program) was used to estimate building heights & widths corresponding to a specific wind direction. Results show that ISCST3 model is not appropriate to describe the building downwash but CFD model, which calculates the flow fields and dispersions simultaneously, is in good agreement with tracer measurements. In order to describe the dispersion induced by building wake near the stack, it is recommended to use CFD model.

가변부하를 이용한 PV모듈의 시험회로 설계

최연옥,이열선,서진연,한승조,조금배 조선대학교 동력자원연구소 1997 動力資源硏究所誌 Vol.19 No.1

A complete computerized system for the characterization and performance testing of photovoltaics(PV) modules under natural sunlight and ambient condition was designed. I-V characteristics of PV module provides on essential diagnostic means in assessing the performance and internal cell parameters of PV module depends on its basic materials, manufacturing technology and operating environmental conditions. I-V curves derived from PV modules refect to a large extent the physical properties and their expected performance. In this paper, Electrical performance measurement and evaluation methods for solar cell module by MOSFET variable Load were studied. Also, Mathematical model and theory of solar cell associated with the photovoltaic effect has been discribed.

토양환경지도 자료를 이용한 콩밭 토양의 화학성 비교

박지숙,이민진,정재원,김미혜,이서연,지윤미,한준호,김유학,공명석,한광현,노희명 忠北大學校 農業科學硏究所 2015 農業科學硏究 Vol.31 No.2

It is important to interpret the soil chemical properties in order to effectively manage the farmland. This study was conducted to investigate the soil chemical properties of upland soybean field according to the soil series at 32 upland fields located in the parts of Gangwon-do. Soil sampling sites were selected by using the National Statistics DB and KSIS DB that is a soil environment information system provided by the Rural Development Administration. Soil samples were collected from 0~15 cm of top soil before seeding or transplanting, air-dried, passed through a 2 mm sieve, and analyzed for soil pH, EC, organic matter, available phosphorus (P2O5), exchangeable potassium, exchangeable calcium and exchangeable magnesium. The average chemical properties have exceeded the each nutrient optimum range level of RDA, except the organic matter in experimental soil 2015. And despite application of conventional fertilization, each soil series nutrient contents were change respectively. The results of this study suggest that conventional fertilization should be applied based on the analysis about the amount of accumulated nutrient contents in the soil.

상악 치아군의 저항중심의 위치에 관한 3차원 유한요소 해석

정광모,성상진,이기준,전윤식,모성서 대한치과교정학회 2009 대한치과교정학회지 Vol.39 No.2

최근 골내 고정 형태의 temporary anchorage device (TAD)를 많이 이용하게 되면서 다양한 위치로부터 그리고 강한 교정력을 이용할 수 있게 되었다. 이에 따라 치아군의 이동양상을 예측하고 치료계획을 세우기 위하여 다양한 치아군의 저항중심의 위치에 대한 이해가 필요하게 되었다. 본 연구에서는 3차원 유한요소해석을 이용하여 상악 4전치, 6전치 그리고 상악 전치열에서 3차원적 저항중심의 위치를 조사하고자 하였다. 이를 위하여 상악 전치열 14개 치아와 치근막 및 치조골의 3차원 유한요소모델을 제작하였고, 각 치아군별로 치관부를 협측, 설측 호선, 설측 splint wire로 고정하여 개별 치아이동을 최소화하고 적용된 힘이 치아에 고루 분산되도록 하였다. 상악 중절치 절단연의 중점에서 연장된 와이어 빔에 수직, 수평으로 100 g 또는 200 g의 힘을 가하여 치아의 변위를 해석하고, 각 치아군에 속한 치아들이 최대한 평행이동 되는 힘의 적용부위를 저항중심으로 정의하였다. 연구결과 상악 4전치군의 저항중심은 상악 중절치 절단연으로부터 치근방향 13.5 mm, 후방 12.0 mm, 상악 6전치군은 상악 중절치 절단연으로부터 치근방향 13.5 mm, 후방 14.0 mm에 위치하였으며 상악 전치열군의 저항중심은 상악 중절치 절단연으로부터 치근방향 11.0 mm, 후방 26.5 mm에 위치하였다. 본 유한요소 실험모델을 이용하여 얻은 결과는 교정치료의 효율성을 높일 수 있으리라 생각된다. Objective: The aim of this study was to investigate the 3-dimensional position of the center of resistance of the 4 maxillary anterior teeth, 6 maxillary anterior teeth, and the full maxillary dentition using 3-dimensional finite element analysis. Methods: Finite element models included the whole upper dentition, periodontal ligament, and alveolar bone. The crowns of the teeth in each group were fixed with buccal and lingual arch wires and lingual splint wires to minimize individual tooth movement and to evenly disperse the forces to the teeth. A force of 100 g or 200 g was applied to the wire beam extended from the incisal edge of the upper central incisor, and displacement of teeth was evaluated. The center of resistance was defined as the point where the applied force induced parallel movement. Results: The results of study showed that the center of resistance of the 4 maxillary anterior teeth group, the 6 maxillary anterior teeth group, and the full maxillary dentition group were at 13.5 mm apical and 12.0 mm posterior, 13.5 mm apical and 14.0 mm posterior, and 11.0 mm apical and 26.5 mm posterior to the incisal edge of the upper central incisor, respectively. Conclusions: It is thought that the results from this finite element models will improve the efficiency of orthodontic treatment.

Retinoic Acid가 흰쥐 태자 혀조직의 분화와 Laminin 합성에 미치는 영향에 대한 연구

김혜주,정호삼,서윤경,백두진,김원규,윤지희,이방헌 대한췌담도연구회 2000 대한췌담도연구회지 Vol.5 No.4

아황산가스가 흰쥐 허파조직내 Laminin 활서에 미치는 영향에 대한 면역조직학적 연구

배성만,정호삼,서윤경,백두진,김원규,윤지희 한양대학교 의과대학 2000 한양의대 학술지 Vol.20 No.2

Sulfur dioxide (SO_2), a kind of air pollutant, causes harmful damage to human body. In particular, inhalation of sulfoxide dioxide has been demonstrated to result in the injury to the upper respiratory duct. However, mechanisms by which SO_2 affects these tissues remain to be clarified. In the present study, to investigate the mechanism of SO_2 effects, the influence of SO_2 exposure was examined in terms of the injury of lung and the expression pattern of laminin in the basal lamina. The basal lamina is an important tissue for the regulation of internal respiration by composing of air-blood barrier. Sprague-Dawley rats repetitively exposed to a mixture of O_2 gas and SO_2 gas (250 ppm) for 30 minutes a day were sacrificed to observe the distribution of laminin in the alveolar septum as well as the morphological alteration of alveoli using immunohistological methods. The resutls we observed were as follows: 1. Alveoli from SO_2-exposed rats (for 5 days) were strongly stained with anti-laminin antibody, suggesting laminin expressed at the high level, at week 1 to 3 upon exposure to SO_2 2. At week 1 to 3 after exposure of rats to SO_2, alveolar septa were collapsed, leading to the reduction of alveolar volume along with morphological changes to irregular shapes. 3. At week 4 to 6 after exposure of rats to SO_2, alveoli were weakly stained with anti-laminin antibody, suggesting laminin expression was decreased during this period. 4. Rats sacrificed at week 7 upon exposure to SO_2 exhibited the expansion of new alveoli and the expression of laminin was partially recovered up to the intermediate level. Taken together, these results demonstrate that the expression of laminin was enhanced in the early phase, followed by downregulation in the late phase. Moreover, lung injury and resolution were correlated with the level of laminin. Thus, these results suggest that SO_2 suppresses the expression of laminin, which may be associated with the neo-generation of lung tissue.