산업 시설물의 강풍 위험 평가 기법의 개발

김학선,이승수,남광현,김용달,홍창문,심규철,김응철,Kim. Hak-Sun,Lee. Sung-Su,Nam. Kwang-Hyun,Kim. Yong-Dal,Hong. Chang-Moon,Shim. Kyu-Cheoul,Kim. Eung-Chul 한국방재학회 2007 한국방재학회 학술발표대회논문집 Vol.2007 No.1

Damages induced typhoons have been increased and super-typhoons have occurred frequently. In our study, we propose a storm risk assessment technique based on CFD for the industrial structures and equipment located in the coastal regions. Inflow wind speeds are obtained through the information of geography and meteorology in considering regions before pressures of wind-environment and structures corresponding to different winds are calculated with wind speed multiplier and pressure coefficient. The results are applicable to evaluate a warning wind speed or regions vulnerable to debris in a considering region and to examine the safety of structures and their exteriors.

국소의치용 티나늄의 피로도 및 물리적 성질에 관한 연구

김학선,김광남,장익태,Kim Hak-Sun,Kim Kwang-Nam,Chang Ik-Tae 대한치과보철학회 1994 대한치과보철학회지 Vol.32 No.2

The purpose of this study was to compare the fatigue, physical properties, flexibility and surface roughness of titanium used in removable partial dentures with those of a type IV and alloy and a cobalt- chromium alloy. Fatigue testing subjected the test specimen to rapid cycling at a given stress until failure occurred by using a small-sized, electrodynamic type bending fatigue testing machine. The S-N curves for the framework materials were generated. For tensile testing, a tensile bar as described in the ADA Specification No.14 was subjected to tensile loading until failure occurred. Load-displacement curves were generated for 18 gauge round specimen and tapered half round specimen. Then the flexibilities were calculated. The surface roughnesses were compared by analyzer. Through analyses of the data, the following conclusions were obtained. 1. The fatigue property of titanium was higher than that of a type IV gold alloy$(p\leq0.05)$, but there was no significant difference between titanium and a cobalt-chromium alloy $(p\geq0.05)$. 2. The yield strength, the ultimate tensile strength and Victors hardness of titanium were higher than those of a type IV gold alloy but lower than those of a coalt-chromium alloy$(p\leq0.05)$. 3. The percentage of elongation and reduction of area of titanium were the highest $(p\leq0.05)$. 4. The surface roughness of titanium was the greatest$(p\leq0.05)$. 5. The flexibility of titanium was lower than that of a type IV gold alloy but higher than that of a cobalt-chromium alloy$(p\leq0.05)$.

골담초근의 생리활성 -고지질, 고혈당 및 간손상에 미치는 영향-

김학선,김일혁,Kim, Hak-Sun,Kim, Il-Hyuk 한국생약학회 1992 생약학회지 Vol.23 No.2

The studies were attempted to evaluated the therapeutic effects of various fractions(ether, methanol, butanol) of Caragana chamlagu roots on the hyperlipemia induced by feeding the diet containing 1%, cholesterol and 0.5%, cholic acid in rats, and on the hyperglycemia induced by streptozotocin in rats. Also the preventive effects of these fractions were studies on the liver damage in $CCl_4-intoxicated$ rats. The followings were obtained as the results: 1.The butanol fraction was significantly shown to down the serum lipid level in 1%, cholesterol and 0.5%, cholic acid diet-feeding rats and streptozotocin-induced hyperglycemic rats. Cholesterol level in $CCl_4-intoxicated$ rats was reduced in the case of all pre-treated groups. 2.The serum glucose level of streptozotocin-induced hyperglycemic rats was significantly decreased by the administration of various fractions of C. chamlagu roots, and the lipid-peroxidation of pancreas was significantly decreased in the case of administration of these fractions. 3.The activates of s-GOT and s-GPT were decreased by the administration of various fractions, especially in butanol fraction, of C. chamlagu roots in the $CCl_4-intoxicated$ rats. The liver lipid-peroxidation was decreased by administration of 200mg/kg of these fractions in the $CCl_4-intoxicated$ rats. In histological observation, hepatic cellular necrosis and fatty acid deposit were increased remarkably by $CCl_4-intoxication$, but the pretreatment of various fractions of C. chamlagu roots improved the pathological change of parenchymatous cell necrosis and fatty change around centrilobular area of the control.

마이크로파 중합에 의한 의치상 레진의 물리적 성질에 관한 연구

김학선,김광남,장익태,Kim, Hak Sun,Kim, Kwang Nam,Chang, Ik Tae 대한치과보철학회 1990 대한치과보철학회지 Vol.28 No.2

The purpose of this study was to investigate the physical propertise and determine whether three were any differences in the amount of porosity of the denture base resins cured by microwave irradiation and conventional water bath heating. The resins used in this study were K-33 resin and Acron MC resin. The properties selected were transverse strength, Knoop hardness, and density. A ten-power eyepiece and scanning electron microscope(Magnification of ${\times}$ 30and ${\times}$150)were used to examine the specimens for porosity. Through analyses of the data from this study, the following conclusions were obtained. 1. Microwave energy can be effectively use dtopolymerize poly(methylmethacrylate) denture base resins. 2. In the transverse strength, K-33 resin cured by microwave irradiation was the first highest, water bath cured K-33 resin the second, microwave cured Acron MC resin the third, water bath cured Acron MC resin the fourth. 3. In the Knoop hardness, K-33 resin cured by microwave irradiation was the first hardest, water bath cured K-33 resin the second, water bath cured Acron MC resin the third, microwave cured Acron MC resin the the fourth. 4. No significant difference was found between the density of resin denture bases polymerized by either method. 5. K-33 resin showed the most porosity for the microwave curing. But there was no significant difference in the Acron MC resin and other curing method.

오리피스 단관 형상이 가스계 소화 노즐 방사 특성에 미치는 영향

김학선(Hak-Sun Kim),노고섭(Go-Sub Noh),황인주(In-Ju Hwang),김윤제(Youn-Jea Kim) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11

난류 모델에 따른 소화 노즐의 유동 특성

김학선(Hak-Sun Kim),김요환(Yo-Hwan Kim),김윤제(Youn-Jea Kim) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12

In this study, the effect of the turbulence models on the noise level of the gaseous fire-extinguishing system was analyzed. In particular, the jet flow characteristics of the discharged extinguish agent were investigated by three-dimensional transient analysis. The numerical analysis was performed using the commercial code ANSYS CFX ver. 18.1 to calculate sound pressure level(SPL) and vortex structure. As a result, the LES turbulence model exhibits the similar trend to the 120 dB experimental SPL data, and could be considered as the suitable turbulence model for this analysis.

SPICE에서의 BJT F<SUP>-1</SUP>잡음 해석 파라미터의 추출에 관한 연구

김학선(Kim Hak Sun),이형재(Lee Hyung Jae) 대한전자공학회 1995 대한전자공학회 학술대회 Vol.1995 No.12

상완골 계단식 절골술의 변형방법을 이용한 내반주 변형의 치료

김학선(Hak-Sun Kim) 대한정형외과학회 1995 대한정형외과학회지 Vol.30 No.1

흡음체 형상 변화가 소화노즐의 방출 특성에 미치는 영향

김학선(Hak Sun Kim),김요한(Yo-Hwan Kim),김윤제(Youn-Jea Kim) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.4

가속화 사회의 시간 테크놀로지 ― 1980년대를 중심으로

김학선 ( Kim Hak-sun ) 한국사회사학회 2020 사회와 역사 Vol.0 No.128

이 글의 목적은 대한민국이 가속화 사회로서 겪고 있는 시간부족감과 관련해서 1980년대의 시간 테크놀로지를 살펴보는 것이다. 시간 테크놀로지란 시간을 한정된 자원으로 인식하고 효율적 이용과 관리를 통해 절약, 단축, 축적을 실현하고자 하는 과학적·경제적·정치적·사회적 방법을 총칭하는 용어이다. 1980년대에 시간성이 크게 변화하면서 대한민국 사회의 가속화 속도가 빨라지게 되었는데, 그 조건을 형성하고 그 방향으로 전진하는 데에 시간 테크놀로지가 중요한 역할을 했다. 1980년대에 달라진 시간 개념과 시간 이용 그리고 과학기술의 발전과 그 관련 담론 등이 상호작용하며 형성된 시간 테크놀로지가 현재에까지 영향을 미치고 있다. 1980년대에는 야간통행 금지제도가 해제됨으로써 24시간을 자유롭게 이용할 수 있게 되었으며, 일상시간이 국가와 사회와 개인의 발전을 위한 자원으로 인식되어 적극적으로 개발되었다. 그리고 자동화 담론이 유행하고, 자동화 기술이 대중화되기 시작했다. 또한 첨단기술을 바탕으로 이루어질 이상향인 ‘테크노피아’가 곧 다가올 현실로 제시되었다. 이런 사회 변화 속에서 다양한 시간 테크놀로지가 개발되었다. 시간을 단축하기 위한 여러 방법들이 개발되고, 24시간의 자유를 이용해서 노동시간과 학습시간을 연장하는 방안이 고안되고, 시간 경쟁력을 높이기 위해 시간 관리와 개발에 매진하는가 하면, 대중적인 자동화 시간에 적응하고 첨단기술사회의 일원이 되기 위해서는 새로운 시간규율을 익히고 미리 준비해야 한다는 인식이 확산되기도 했다. 1980년대에 개발된 시간 테크놀로지들의 변모 양상은, 현재 대한 민국 사회가 가속화로 인해 겪는 문제점을 해결하고자 그 속도와 방향을 재고할 때 참고사항이 될 수 있을 것이다. This article examines the time technologies of the 1980s in South Korea and its experience as an ‘acceleration society.’ Time technology refers to the scientific, economic, political, and social methods that seek to conserve, reduce, and accumulate efficient use and management of time―a limited resource. The 1980s marked a period of rapid change in the concept of time and contributed to South Korea’s acceleration. Time technologies played crucial roles in shaping certain conditions for and the directionality of change. Such technologies fostered new views of time recognition and management, scientific development, and social acceleration. The lifting of the nationwide curfew in the 1980s meant that citizens could freely use the 24 hours of the day. Daytime became a resource for the country, society, and individual development. Discourse on automation also became prevalent. Technopia, a utopia based on advanced technology, became a more tangible reality. Various time technologies have been developed in the midst of these social changes. A variety of methods helped reduce and extend the time for work and study now that citizens had gained 24-hour freedom. There was a growing widespread awareness that society needed to adapt to flourish as citizens of a high-tech society; it would have to learn and prepare in advanced new rules of time. The transformation of 1980s time technologies in South Korea serve as a reference for rethinking problems in modern Korean society encountered by social acceleration.