낮은 Pr수를 갖는 순수 물질에서의 진동대류에 관한 수치 해석

현명택,홍남호,이동원 濟州大學校工科大學産業技術硏究所 1997 尖端技術硏究所論文集 Vol.8 No.1

Numerical study was investigated to the transient natural convection in a square cavity. The cavity is filled with the pure substance of a low Prandtl number and the vertical walls are constantly maintained different temperature, while the horizontal boundaries are adiabatic. A control volume approach with a central difference scheme is used to formulate the finite difference equations. The results were presented transient Nusselt number, stream function and temperature distribution. It was found that the flow pattern and heat transfer exhibit time-periodic oscillation at various conditions. The average Nusselt number, the amplitude and the frequency of oscillation increases as the Rayleigh number is increased. The increment of Prandtl number makes that the amplitude and the frequency of oscillation reduced, and average Nusselt number increased.

봉다발 온도장 해석을 위한 난류 Prandtl 수 모델 개발

현명택,김신 濟州大學校工科大學産業技術硏究所 1999 尖端技術硏究所論文集 Vol.10 No.1

The turbulent Prandtl number is a useful concept for engineering calculations. However, most turbulent Prandtl number are developed for simple geometries like circular tube and parallel plates and these seem to be inadequate for rod bundles like nuclear subchannels. In this study, based on some recent measurements of turbulent Prandtl numbers in rod bundles and general behaviors of the dimensionless number, a turbulent Prandtl numbers model for road bundles is proposed. Also, thermal hydraulic fields in rod bundles are numerically predicted with the proposed model and the average Nuseelt numbers are successfully compared with well-known empirical correlations.

복합부력에 의한 사다리꼴 용기내에서의 유동 형성 과정에 관한 연구

현명택 제주대학교 1992 논문집 Vol.35 No.-

Numerical solutions for double-diffusive convection, subject to the externally imposed horizontal temperature gradient and vertical solute gradient in an equilateral trapezoidal enclosure, are secured. Insepection of the large-time numerical solutions clearly points to the existence of four distinct flow regimes. When N is very small, the overall flow properties are similar to those of a purely thermal convection. For the increasing values of N, the distinguished feature is the emergence of multilayered flow structure. Layered flow structure with stagnant zone is appeared for the relatively high buoyancy ratio. When N is large, the fluid in the bulk of the container is essentially motionless.

제주 벤쳐기업의 경영특성 분석

서현진,현명택 제주대학교 경상대학 경영경제연구소 2000 경영경제연구 Vol.2 No.-

건강성인자원자에 있어서 Theophylline과 β_(2)-adrenergicagonists (Procaterol 및 Albuterol)의 약동학적 상호작용

신현택,권현명,김호순 숙명여자대학교 약학연구소 1998 약학논문집-숙명여자대학교 Vol.14 No.-

Theophylline and adrenergic β₂ -agonists are frequently used together in bronchial asthma and chronic obstructive pulmonary disease(COPD). Among the adrenergic β₂ -agonists, procaterol and albuterol are most frequently used with theophylline in Korean hospitals. The effect of procaterol and albuterol administration on pharmacokinetics of theophylline was studied in 11 normal healthy volunteers(6 males, 5 females). The theophylline clearances with and without /J-adrenergic agonist (procaterol) were 38.76 + 9.53 ml/kg/hr and 32.46 + 8.46 ml/kg/hr respectively, which were not statistically significant. Similar result was seen with albuterol. The values of AUC, T_(1/2), Ke and Vdss were not influenced by either procaterol or albuterol. Also, there was no significant change in cardiac output and heart rate. In conclusion, adrenergic β₂ -agonists (procaterol and albuterol) do not alter theophylline pharmacokinetics.

방사선치료 후 영구치 치배 발육장애 증례보고 : REPORT OF CASE

강명봉,김영재,김정욱,장기택,이상훈,한세현,김종철 大韓小兒齒科學會 2005 大韓小兒齒科學會誌 Vol.32 No.2

두경부 악성 종양에 대한 방사선치료는 유용한 방법이다. 하지만 방사선치료의 부작용으로 다양한 구강내 합병증을 동반한다. 이 글에서 치열 발육 단계에 방사선치료를 받은 두 증례를 보고하는 바이다. 첫 번째 증례는 생후 19개월에 급성 골수성 백혈병으로 진단 받아 방사선치료를 받은 7세 여자 환아로 영구치 치배의 선천적 결손과 왜소치 소견을 보였다. 두 번째 증례에서는 생후 13개월에 양측성 망막아세포종으로 진단 받아 방사선치료를 받았고 영구치 치배의 선천적 결손, 왜소치, 치근의 저형성 그리고 법랑질 저형성증 소견을 보였다. Radiotherapy for head and neck tumors is a viable treatment modality. However, a wide range of potentially debilitating dental complications may be accompanied by this treatment. We report two cases of developmental disturbance of permanent tooth germs after radiotherapy. The one was that of a seven-year-old girl, who had congenitally missing teeth, and microdontia of permanent tooth germs. she had received radiotherapy for acute myelocytic leukemia at the age of 19 months. The other was that of a nine-year-old boy, in which congenitally missing teeth, microdontia, root hypoplasia, and enamel hypoplasia of permanent teeth were observed. He had undergone a course of radiotherapy for bilateral retinoblastoma at the age of 13 months.

경관영향평가 항목선정을 위한 타당성 평가

오명성,조현주,이현택,나정화 경북대학교 농업과학기술연구소 2008 慶北大農學誌 Vol.26 No.-

This research is significant in terms of estimating the validity by setting evaluation items in view of integrating not only original beauty and visual areas but also natural ecological areas based on questionnaire. The results are as follows. 1) According to literature study, 17 items such as variety, the character of sites in terms of landscape, the beauty of landscape, visibility, and ratio of green visibility are selected. Also, 21 items such as variety of animals and plants species, size of green area, and ecological naturalness are selected m the area of landscape ecological resources. 2) As a result of questionnaire of the group of landscape experts, animals and plants ecological areas show 5.6341, the highest in importance analysis according to assessment areas. Also, as a result of importance analysis on items in each area, for example, in the area of visual resources, the item of skyline analysis is 6.0488, the highest. 3) As a result of corelation of item meaning on landscape effect assesment, for example, meaningness of psychological assessment item and landscape site item indicate 0.710, the highest coefficient correlation. 4) As critical assessment items per unit project, items such as damage minimization of original land features for project in terms of point, ratio of green visibility, variety of animals and plants species marked above 8.0 as high important medium. The project in terms of line, minimization of original land features, Preservation of worthy biotope showed high point and the character of sites in terms of landscape, minimization of original land features, the size of green area, and analysis of skyline marked above 8.5 as high importance points. On the contrary, items for climate and soil showed relatively low points.

파손된 치면열구전색제의 수리 방법에 따른 미세누출 비교

강명봉,현홍근,김영재,김정욱,장기택,이상훈,한세현,김종철 대한소아치과학회 2007 大韓小兒齒科學會誌 Vol.34 No.2

치면열구전색은 수 십년간 교합면 우식의 예방에 가장 효과적인 방법 중 한가지로 알려져 왔다. 하지만 치면열구전색제의 마모와 파절 때문에 치면열구전색제의 재시술 또는 수리를 필요로 하게 되었다. 본 연구의 목적은 파손된 치면열구전색제를 수리할 때 치질과 잔여 전색제의 표면처리 방법에 따른 미세누출 차이를 알아보고자 하는 것이다. 120개의 영구 대구치에 치면열구전색제를 적용하고 인위적인 파손을 만든 뒤 인공타액에 4주 동안 보관하였다. 4주 후 근심 또는 원심의 치면열구전색제가 완전히 파손 양상을 나타내는 치아 60개를 선택하여 각각 15개씩 4개 군으로 나누어 실험에 사용하였다. 각 군을 산부식만 시행한 경우(1군), air-abrasion만 시행한 경우(2군), 산부식 후 결합제를 적용한 경우(3군), air-abrasion 후 결합제를 적용한 경우(4군)로 나눠 각각의 치아를 표면처리한 후 치면열구전색제를 도포하였다. 고온(55℃)과 저온(5℃)에서 각각 30초씩 500회의 열순환을 시행한 뒤 미세누출도를 검사하여 다음과 같은 결과를 얻었다. 1. 치면열구전색제/치면열구전색제 경계면에서 미세누출도는 결합제 사용 유무에 관계없이 air-abrasion을 처리한 2군, 4군에서 산부식을 사용한 1군, 3군보다 낮은 값을 보였고(p<0.05) 1군과 2군, 3군과 4군 사이에는 통계적 유의차가 없었다(p>0.05). 2. 치면열구전색제/치아 경계면에서 미세누출도는 결합제를 사용한 3군, 4군에서 결합제를 사용하지 않은 1군, 2군보다 낮은 값을 보였고(p<0.05) 산부식을 사용한 1, 3군과 air-abrasion을 사용한 2, 4군 사이에는 통계적 유의차가 없었다(p>0.05). 3. SEM 상에서 치면열구전색제를 산부식 처리하였을 때 표면거칠기의 증가가 적었으나 air-abrasion 하였을 경우 표면거칠기가 현저하게 증가하는 것을 관찰하였다. The aim of this study was to investigate whether differences in surface treatment Prior to repair influenced the seal of a resin fissure sealant placed on the occlusal surfaces of permanent molar teeth. One hundred and twenty extracted human molars were selected and a light curing sealant was placed on their occlusal surface following cleaning by prophylaxis and acid etching. The teeth were deliberately damaged, and then stored in artificial saliva for four weeks. Sixty teeth with the desired morphology of sealant failure were randomly divided into four groups where one group was treated with only etching agent, another by only air-abrasion, another by applying an etching agent followed by a bonding agent, and the last by air-abrasion followed by a bonding agent each. After sealant application, the samples were thermocycled and the degree of microleakage was determined. The results were as follows: 1. In the sealant/sealant interface, group 2(0.22), 4(0.23) using air-abrasion showed a significantly lower microleakage score than group 1(0.38), 3(0.35) using an etching agent(p<0.05). There were no statistically significant differences(p>0.05) between groups 1, 2 and groups 3, 4. 2. In the sealant/tooth interface, group 3(0.20), 4(0.20) which used a bonding agent showed a significantly lower microleakage score than group 1(0.35), 2(0.40)(p<0.05). There were no statistically significant differences (p>0.05) between groups 1, 3 and groups 2, 4. 3. In SEM examination, while sealant surfaces treated with etching did not result in highly rough surfaces, those treated with air-abrasion did show rough surfaces.

봉다발 온도장 해석을 위한 난류 Prandtl 수 모델 개발

김신,현명택 濟州大學校 産業技術硏究所 1999 산업기술연구소논문집 Vol.10 No.1

The turbulent Prandtl number is a useful concept for engineering calculations. However, most turbulent Prandtl number models are developed for simple geometries like circular tube and parallel plates and these seem to be inadequate for rod bundles like nuclear subchannels. In this study, based on some recent measurements of turbulent Prandtl numbers in rod bundles and general behaviors of the dimensionless number, a turbulent Prandtl number model for rod bundles is proposed. Also, thermal hydraulic fields in rod bundles are numerically predicted with the proposed model and the average Nuseelt numbers are successfully compared with well-known empirical correlations.

건물 신선 외기 태양열 난방 제어 시스템에 관한 연구

권기린,현명택,강은철 제주대학교 공과대학 첨단기술연구소 2002 尖端技術硏究所論文集 Vol.13 No.2

Unglazed solarwall installed in south wall is to preheat fresh air by solar insolated energy. This system has been proved as cost effective and easy to design and install and even operate. So, advanced countries such as Canada and USA have already developed and applied the solar wall systems. KIER has started to work on design, analysis and control of the solar wall system. The purpose of this paper is to introduce the solar wall fresh air heating control system. The control system logic as well as hardware will be explained. The impacts of solar wall control system on the room temperature have been investigated. The designed control system to keep the room temperature constant between 18℃ to 25℃ could be developed and demonstrated with LabVIEW 6i software and DAQ hardware in KIER.