강재의 단축인장 시험과 마모와의 관계

오흥국,연규현,김태훈 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.4

The reorientations of the atoms by frictional shear deformation at the surface induce cracks at the boundary of the grain. The cracks grow and propagate in regions where the hydrostatic component of stress is least com-pressive because the compressive component restores the cracks by three-dimensional crystallizing π-bondings. The materials, with Luder's band have very small amount of wear at the initial state. It suggests that initial frictional shear deformation be consumed to the formation of the Luder's band. The average wear amounts of the materials increase very steeply as the ø_u, the stress-strain ratio at the ultimate point, decreases.

퍼팅 동작 영상분석 시 프레스 동작의 이벤트 설정 가능성 여부

박태진,서국웅,서국은 釜山大學校 附設 體育科學硏究所 2009 體育科學硏究所 論文集 Vol.25 No.1

본 연구는 부산.경남지역에서 세미프로로 활동 중인 7명을 선정하여 퍼팅(10.94 m)동작 시 프레스 동작을 3차원 영상 기법을 통해 운동학적으로 비교.분석하여 얻은 결론은 다음과 같다. 첫 번째, 양손은 어드레스를 취한 후 백스윙되기 전까지 볼 진행 방향으로 움직이는 것으로 나타났다. 두 번째, 퍼터헤드, 몸통, 어깨 중심점은 프레스 동작 시 좌.우 방향으로 움직이지 않고 고정되어 있는 것으로 나타났으며, 프레스 시 양손 중심점은 어드레스 시 보다 임팩트 시에 가까운 것으로 나타났다. 세 번째, 퍼팅 스트로크 시 총소요시간 중 프레스 동작이 22.83%를 차지하고, 구간 중 다운스윙과 팔로스루 시간 보다 많이 소요되는 것으로 나타났다.

釜山大 男學生의 體力 및 身體遂行 能力에 關한 硏究

金泰運,徐國雄,金命祚,趙福德,黃喆文 釜山大學校 附設 體育科學硏究所 1988 體育科學硏究所 論文集 Vol.4 No.-

The purpose of this study was measure height, weight, chest girth, sit and reach, grip strength, back strength, % body fat and VO₂max for freshman students majoring in engineering in Puasn National University. In comparison with the results of other studies, the following conclusion were drawn. A. Height(172 ±4㎝) and weight(62 ±7㎏) were increased, but chest girth(87 ±6㎝) decreased. B. VO₂max(2.4 ±0.31/min 38 ±38 ±6ml/㎏/min) and % body fat (7 ±4%) were significantly low. C. Questionaire revealed 16% of subjects exercise 4∼5 hours per week D. Questinmaire revealed that smokers and drinkers are 18%, 86% respectively.

다이벤조 테트라아자펜타렌 (Dibenzotetraazapentalene) 유도체들의 생성에 관한 치환기 효과

朴國泰 全北大學校 1981 論文集 Vol.23 No.-

The rates of deoxygenative cyclization by triethyl phosphite in solvents of varying dielectric constants has been measured for 1-(ο-nitrophenyl)-1 H-benzotriazole, 2-(ο-nitrophenyl)-2H-benzotriazole, and 5-chloro-1-(ο-nitrophenyl)-1H-benzotriazole. The reactions were found to be second order overall, insensitive to the dielectric constants of the solvents, and characterized by a large negative entropy of activation. The rate constants of deoxygenative cyclization of 1-(ο-nitrophenyl)-1H-benzotriazole and 5-chloro-1-(ο-nitrophenyl)-1H-benzotriazole were similar. These findings are consistent with the rate-determining step involving the formation of a four-membered cyclic transition state.

표본화 및 유지회로 성능향상에 관한 연구

홍국태,이성대,정강민 成均館大學校 科學技術硏究所 1995 論文集 Vol.46 No.1

In this paper, a high speed, high accuracy sample and hold circuit that minimizes the hold step error by using a new circuit architecture is proposed. This new sample-and-hold scheme takes advantages of the speed of the open loop sample-and-hold circuit in the SAMPLE time and the cancellation of charge injection in the HOLD time. It operates above 50MHz with 0.3mV hold step error.

시각장애인용 점자학습기 개발에 관한 연구

최태종,장병태,김정국,허웅 명지대학교 산업기술연구소 2001 産業技術硏究所論文集 Vol.20 No.-

This paper descirbes a Braille training system that helps to learn braille effectively. The system converts written text to voice and exerts braille tactile pins simultaneously according to the text. The system consists of a voice sysnthesis device for converting text to voice, tactile device, and software to control the devices. The tactile device includes a control unit, pin array, pin action generator, serial port, and a power supply, and the tactile pins are exerted by solenoid. The Braille training system has been used to teach braille to people who do not know braille at all. It is found that the group of people who learned braille with the system showed much better braille recognition capability compared to the group who learned braille by traditional method. Therefore, the Braille training system can be effective in learning braille.

회전 자계에 의해 초전도체에 발생되는 Eddy current 분포에 관한 연구

고태국,최진형,오윤상 연세대학교 산업기술연구소 1993 논문집 Vol.25 No.2

The distribution of magentic field and eddy current is analized to investigate the normal spot wihich plays a part in excitation. Magnetic Reynods Number has been introduced to explain the distribution of magnetic field and eddy current. Through the eddy current equation, we can predict where the quenching points are formed in superconductiong sheet. The part of zero-compression by motion. When the magnetic of the normal spot is large, the eddy current is increased in the side of normal spot and decreased in the left side. So the current reaches to the critical current, the superconductor begins to quench locally.

위암발증 원인에 대한 생활습관 및 영양섭취에 있어서 농촌지역 주민 조사 : 강원도 화천군 주민의 Helicobacter pylori 감염률을 중심으로 Infection of Helicobacter pylori in Whachon Area, Kang-Won Do

권태봉,이정선,우영국,이명헌,정철원,주진순 한국식품영양학회 1999 韓國食品營養學會誌 Vol.12 No.1

위암발증의 원인을 밝히기 위하여 설문조사를 통하여 강원도 화천군에 거주하는 주민들의 일반사항, 생활습관 및 영양섭취실태와, ELISA법으로 Helicobacter pylori 감염률을 조사하였다. 조사 대상자는 40∼69세까지의 지역주민 169명으로 남자 79명, 여자 90명이었으며 그 결과는 다음과 같다. 조사 대상자의 학력은 65.7%가 초등학교 이하였으며, 월수입은 60%가 50만원 이하였다. 대상자의 62.7%가 농업에 종사하였고 자녀수는 64.3%가 3∼5명이었으며 대상자의 34.5%가 흡연을 하고 있었고 68.4%가 음주를 한다고 대답하였다. 대상자의 전체 평균신장은 156.7㎝로 여자는 150.1㎝, 남자는 164.4㎝ 이었다. 평균체중은 61.1㎏으로 여자의 체중은 57㎏, 남자는 65.7㎏이었으며 BMI는 전체 평균 25.5%로 여자는 24.8%, 남자는 20.1%이었다. Helicobacter pylori의 감염률은 전체 조사대상자의 66.3%이었으며, 여자의 67.7%, 남자의 64.6%가 감염되었고 연령별로는 40대의 70%, 50대의 62.2%, 60대의 69.4%가 각각 감염된 것으로 나타났다. 일상 생활 요인에 따른 Helicobacter pylori의 감염률은 흡연의 정도가 심하고 학력이 낮으며 월수입이 낮을수록 높은 경향을 보였다. Helicobacter pylori의 감염여부에 따라 감염자와 비감염자의 영양섭취량을 조사해 본 결과 비감염자는 감염자와 비교해서 에너지, 총단백질, 동물성 단백질, 칼슘, 비타민 C 섭취량이 높은 경향을 보였으며 철분과 niacin의 섭취량은 낮은 경향을 보였다. To examine the relationship between the casual infection of gastric cancer and lifestyle and nutritional status, we surveyed 169 persons, 90 females and 79 males, aged 40∼69 years from June 7 to June 14, 1997, in Whachon area, Kang-Won Do, Korea. For this purpose, we investigated Helicobacter pylori infection and identified the effect of sex, age, smoking, alcohol consumption, economic status, occupation, life-style and food intake on Helicobacter pylori infection. Helicobacter pylori status was evaluated using an enzyme-linked immunosorbant assay(ELISA) for anti-Helicobacter pylori immunoglobulin G(IgG). Helicobacter pylori infection was present in 66.3% of total subjects, namely, 67.7% of female and 64.6% of male and its prevalence increased with smoking, low education level and low monthly income. Energy, total protein, calcium and vitamin C intakes in the negative Helicobacter pylori infection group were higher than those in positive Helicobacter pylori infection group. However iron and niacin intakes were lower in the Helicobacter pylori negative group than in the positive group.

대기중의 습도에 따른 탄소강의 마모와 마찰

오흥국,연규현,김태훈 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.3

The atmospheric humidity is varied between 30% and 90% with season in Korea. Thus the influence of humidity on the behavior of wear is important to predict the wear for tools and dies. This paper presents the influence of atmospheric humidity on the wear of carbon steels for the un-lubricated pin-on-disk sliding contact. It was found that the severe wear is dominant at a low humidity and the mild wear is strongly related with the carbon concentration of the steel at a high humidity in this study. The experiments were caned out in a chamber where the humidity was accurately maintained by humidifier. To investigate the relationship, three different carbon steels such as 1020, 1041, and 1045 steels were used.

Zinc Titanate에서 H₂S 흡수특성 조사

이태진,박노국,권원태,장원철,박영성 嶺南大學校 環境問題硏究所 1996 環境硏究 Vol.16 No.1

요약문사출성형법으로 평가를 위해 ZnO 함량을 변화시키면서 4종류의 Zinc Titanate 흡수제를 제조하였다. Zn/Ti 몰비가 증가할수록 지배적인 결정상은 Zn 2Ti3O8과 Zn2TiO4로 관찰되었다. Zinc Titanate 탈황제에 의한 H2S 흡수반응을 모사석탄가스의 고온탈황에 의해서 실험적으로 연구하였다. 내경 3cm인 석영관의 고정상 반응기로 4종류의 Zin cTitanate 흡수제에 대하여 H2S 흡수와 재생의 10-cycle 실험을 수행하였다. 파과곡선, SEM, BET 등의 실험적인 관찰을 근거로 하여 650℃가 최적 흡수반응온도임을 결정하였다. 탈황과 재생의 반복적인 실험동안 H2S와 S02의 파과곡선들을 구하였다. 또한, 시험 전후의 흡수제의 물성변화를 SEM, EDX, Hg-porosimetry 및 BET 방법으로 분석하였다. 비록 더많은 연구가 필요하지만, 제한된 실험적 조건에서 판단하면 YZT-3(Zn/Ti=1.5)가 가장 우수한 탈황제라고 결론내릴 수 있다.AbstractFour zinc titanate sorbents were prepared for evaluation by extrusion method with varying ZnO contents. The predominant crystalline phases were Zn2Ti3O3 and Zn2TiO4 as Zn/Ti molar ratio was increased. Absorption of HzS by the zinc titanate sorbents was studied experimentally in high temperature desulfurization of simulated coal gas. Fixed-bed system of 3 cm i. d. quartz tube was used to carry out 10-cycle experiments of H2S absorption and regeneration for the zinc titanate sorbents. In these experiments the optimal absorption temperature was determined as 650 ℃ based on experimental observation of breakthrough curves, SEM and BET results, and so on. H2S and SO; breakthrough curves were obtained for each sorbent during repetitive cycles of desulfurization and regeneration. Also, property changes of the sorbent before and after testing were analyzed using SEM, EDX, XRD, Hg-porosimeter and BET method. It is concluded under this limited experimental conditions YZT-3 (Zn/Ti =1.5) was the most suitable desulfurization sorbent even though further tests are required.