장력법을 적용한 박판블록의 변형제어에 관한 연구

김철호,양종수,김호경,Kim, Cheol-Ho,Yang, Jong-Soo,Kim, Ho-Kyung 대한용접접합학회 2007 대한용접·접합학회지 Vol.25 No.6

The weld-induced deformation is more serious in thin plates than in thick plates because heat affect zone of thin plates is wider than that of thick plates and in addition internal and external constraints have much more influence upon weld-induced deformation of thin plates. This paper deals with the application of the mechanical tensioning method to butt weld of thin plates to reduce the transverse and longitudinal deformation. In order to investigate the quantitative effect of tensioning method upon the reduction of angular deformation and shrinkage in longitudinal and transverse direction of weld line, butt welding test has been carried out for several thin plate specimens with varying plate thickness and magnitude of tensile load. From the present experimental study, it has been found that the tensioning method is very effective in reducing the weld-induced residual stress as well as the weld-induced deformation.

초전도 결정의 저온 비열 점프의 자기장 의존성

김철호,Kim, Cheol-Ho 한국재료학회 2011 한국재료학회지 Vol.21 No.2

Specific heat of a crystal is the sum of electronic specific heat, which is the specific heat of conduction electrons, and lattice specific heat, which is the specific heat of the lattice. Since properties such as crystal structure and Debye temperature do not change even in the superconducting state, the lattice specific heat may remain unchanged between the normal and the superconducting state. The difference of specific heat between the normal and superconducting state may be caused only by the electronic specific heat difference between the normal and superconducting states. Critical temperature, at which transition occurs, becomes lower than $T_{c0}$ under the influence of a magnetic field. It is well known that specific heat also changes abruptly at this critical temperature, but magnetic field dependence of jump of specific heat has not yet been developed theoretically. In this paper, specific heat jump of superconducting crystals at low temperature is derived as an explicit function of applied magnetic field H by using the thermodynamic relations of A. C. Rose-Innes and E. H. Rhoderick. The derived specific heat jump is compared with experimental data for superconducting crystals of $MgCNi_3$, $LiTi_2O_4$ and $Nd_{0.5}Ca_{0.5}MnO_3$. Our specific heat jump function well explains the jump up or down phenomena of superconducting crystals.

한국 동해안에 출현하는 냉수괴의 특성과 기원

김철호,김구,Kim, Cheol Ho,Kim, Kuh 한국해양학회 1983 韓國海洋學會誌 Vol.18 No.1

To serch the origin of the cold water mass along the east coast of Korea its characteristics are inrestigated based upon Cooperative Study of Kuroahio and Fisheries Research and Development Agency data. In the southwestern part of the Japan Sea the North Korean Cold Water sinks at the front and flows southwards on top of the Japan Sea Proper Water. it is found that the sunken North Korean Cold Water il high in the content of dissolved oxygen and less saline compared with the Japan Sea Proper Water. It is highly likely that the cold water mass off the Jugbyeon-Chuksan coast in summer il the North Koreah Cold Water and not upwelled Japan Sea Proper Water. It os shown that the Notth Korean cold Water Flows strongly in summer and its scuthern limit is generally off Chuksan-Janggigab and occasionally off Gampo as observed in 1973.

세균에 의한 남조 Anabaena cylindrica의 분해에 대한 연구

김철호,권오섭,이진애,Kim, Cheol-Ho,Gwon, O-Seop,Lee, Jin-Ae 한국조류학회(藻類) 2003 ALGAE Vol.18 No.4

A Gram (-), rod-shaped bacterium in size of 1.6-2.8 $\times$ 0.4 μm was isolated from a eutrophic reservoir, which exhibited growth-inhibiting effect against a bluegreen alga (Anabaena cylindrica). This isolate showed positive reactions for catalase and oxidase, and optimal conditions of 35-40°C and pH 9.0. This isolate was designated AC-1 in this manuscript. In a mixed-culture of A. cylindrica and AC-1, their growth patterns were inversely correlated and the bluegreen algal vegetative cells completely disappeared within 24-36 hours. AC-1 showed similar lytic activity in natural water as in an artificial medium. The lytic activity of AC-1 was dependent on the photosynthetic activity of A. cylindrica. When observed under phase contrast microscope, the isolate lysed vegetative cells of A. cylindrica in scattered state in a liquid medium, whereas heterocysts have not been lysed.

개에서의 indocyanine green 배설시험 및 혈장효소 활성치의 변화

김철호,최일관,손민수,김진구,강정부,Kim, Cheol-ho,Choi, Il-kwan,Son, Min-soo,Kim, Jin-gu,Kang, Chung-boo 대한수의학회 1992 大韓獸醫學會誌 Vol.32 No.4

This experiment was carried out to establish a proper method of indocyanine green(ICG) excretion test for a applicable liver function test in dogs. The half life(T1/2), fractional clearance rate(KICG) and retention rate after injection of ICG with or without administred carbon tetrachloride($CCl_4$) were also invested. The results obtained were as follows ; 1. The maximum absorbance of ICG in plasma was at 810nm. 2. Half life and fractional clearance rate when administered 0.25 and 0.50mg of ICG per Kilogram body weight were $6.33{\pm}0.58$ minutes and $0.11{\pm}0.99$/minute in the former, $10.01{\pm}1.0$ minutes and $0.07{\pm}0.007$/minute in the latter, respectively. The ICG removal rate was exponentially linear for the first 15 minutes after injection both, of 0.25 and 0.50mg of ICG. 3. One day following the administration of $0.0042m{\ell}\;CCl_4$ kilogram body weight which injected 0.50mg of ICG, half life was more longer and fractional clearance rate was significantly reduced than that of ICG single injection. 4. Plasma retention rate when 15, 30, 45 minutes after injection dose of 0.25 and 0.50mg ICG per Kilogram body weight, $14.7{\pm}4.8$, $5.1{\pm}3.1$, $2.6{\pm}1.6%$ in the former, $26.9{\pm}1.8$, $11.1{\pm}2.4$, $4.8{\pm}1.3%$ in the latter, respectively. However, after administration of $CCl_4$, plasma retention rate of ICG at a dose of 0.50mg, it was $39.3{\pm}0.9$, $16{\pm}2.9$, $10.7{\pm}0.1%$, respectively. 5. Plasma enzyme(AST, ALT, r-GTP) activities administered with $CCl_4$ were increased, but there was no change which injected any dose of single ICG injection. From these results, ICG excretion test to dog is applicable to evaluation of liver function in both clinical and research.

저온에서 초전도 결정의 비열 점프

김철호,Kim, Cheol-Ho 한국결정성장학회 2011 한국결정성장학회지 Vol.21 No.1

본 논문에서는 먼저 저온에서의 초전도 결정의 비열 점프를 임계 온도의 함수로 구하였다. 다음에, 구한 비열 점프의 부호와 크기 등을 분석하여 여러 가지 실험적인 사실들을 예측하였다. 마지막으로 우리가 예측한 실험 사실과 실제의 실험이 일치하는지 비교하였다. 이론적으로 구한 비열점프는 $YNi_2B_2C$ 결정의 비열 점프 업 과 비열 점프 다운 현상을 비교적 잘 설명한다. 특히 매우 낮은 온도에서는 상전도-초전도 전이 시에 비열이 점프 다운된다는 주목할 만한 이론적 예측을 실험 결과를 통해 확인할 수 있었다. In this paper, firstly we have derived and presented the specific heat jump as a function of the critical temperature. Secondly, we have analyzed the sign and magnitude of the derived specific heat jump and predicted the expected experimental results. And lastly, we have compared the expected experimental results with the real experimental results. Theoretically derived specific heat jump is considerably compatible with the specific heat jump up and down phenomena of the $YNi_2B_2C$ crystal. Especially, the remarkable theoretical prediction-hat the specific heat would jump down during the normal state-to-superconducting state transition at extremely low temperatures-have been confirmed by the experimental results.

벤처기업 블루오션 디자인에서 찾다

김철호,Kim, Cheol-Ho 벤처기업협회 2005 벤처다이제스트 Vol.82 No.-

하천의 어제, 오늘 그리고 내일 1 - 원주천의 역사와 문화

김철호,Kim, Cheol-Ho 한국하천협회 2013 하천과 문화 Vol.9 No.1

흡착입자간 상호작용에 따른 흡착등온선 패턴

김철호,Kim, Cheol Ho 한국재료학회 2013 한국재료학회지 Vol.23 No.8

We study and describe-from the point of view of the interactions of the adsorbed particles-three types of the adsorption isotherms, namely, Langmuir type adsorption isotherms, phase transition type adsorption isotherms, and adsorption limited type adsorption isotherms, which are observed by experiments. By introducing and using a one dimensional statistical occupancy model, we derived analytical adsorption isotherms for the no force, the attractive force, and the repulsive force exerted on the other adsorbed particles. Our derived adsorption isotherms qualitatively pretty well agree with the experimental results of the adsorption isotherms. To specify each adsorption type, Langmuir type adsorption is a phenomenon that occurs with no forces between the adsorbed particles, phase transition type adsorption is a phenomenon that occurs with the strong attractive forces between the adsorbed particles, and adsorption limited type adsorption is a phenomenon that occurs with the repulsive forces between the adsorbed particles. The theoretical analysis-only using fundamental thermodynamics and occupancy statistics though-qualitatively quite well explains the experimental results.

세나라 책방을 둘러보고 프랑크푸르트도서전을 다녀와서

김철호,Kim, Cheol-Ho 대한출판문화협회 1993 출판저널 Vol.138 No.-

우리가 '출판선진국'에게서 배울 건 책을 보는 그들의 관점과 태도이지 책을 만드는 기술과 방법은 아니다. 유럽의 어린이책 편집자들은 어린이를 어른과 똑같다고 생각하는 것 같다. 또한 어린이용 그림책에는 책마다 전력투구하는 작가의 예술혼이 있다. 영국.프랑스.독일의 책방을 보고 온 필자의 유럽아동물에 대한 인상기를 통해 우리 아동물출판 실태를 돌아본다.