溫熱및 寒冷이 成熱白鼠 肝細胞핵分裂에 미치는 影響에 關한 實驗的 硏究

鄭九鉉 中央醫學社 1965 中央醫學 Vol.8 No.6

In order to observe the effect of, the temperatures upon the hepatic cell mitosis, albino rats weighing from 120 gm, to 150 gm were kept in an incubator at the temperature of 32 °C, or in a refrigerator at the temperature of minus 10 °C for a certain period respectively, and than hepatic cell mitosis was timely observed. In another hand, a small amount of serum of the albino rats which have been exposed in the above two temperatures was injected into unexposed normal albino rats, and the effect of injected sera upon the hepatic cell rnitosis also was observed? And the following conclusions were obtained. 1) In the group of the albino rats which were exposed in the temperature of .30°C, for a certain period, their hepatic cell mitosis has shown the rapid increase in it's activity since 4 houter after exposure, and thereafter reached in 12 hours the maximum level which is five to six times of that in the unexposed group, 24 hours later it returned to the normal level due to the gradual decrease in it's activity, However, the continuous decrease of hepatic cell mitosis reaches the minimum level in 48 to 72 hours and returned again to the normal level. 2) In the group of the albino rats which were exposured in the temperature of minus 10°C for a certain period, the hepatic cell mitosis also has shown the relatively rapid increase in it's activity since 4 to 8 hours after exposure and reached the maximum level in 18 hours, which is more than two times of the unexposed, "Thereafter the hepatic cell mitosis decreased in it's activity relatively repidly in 'one fourth of the normal level in 48 to 72 hours, And a tendency returning to the normal level in one week due to gradual decrease in mitotic activity was also observed. 3) In the group injected with the serum of the albino rats exposed in the temperature of 32°C, for a certain period, the hepatic cell mitosis seemed to slightly decreased in it's activity immediately after the injection. However, thereafter it showed the rapid increase in it's activity reaching the maximum level in 8 to 12 hours, which is about two times of that in the uninjected, And then the relatively rapid decrease in mitotic activity was shown and it became about me third .of that in the uninjected in 24 hours, and returned to the normal level due to the gradual: decrease thereafter. 4) In the group injected with the serum of the albino rats exposed in the temperature of minus 10°C for a certain period, a tendency of more. or less slight decrease of the hepatic cell mitosis was shown immediately after the injection. And the hepatic cell mitosis reached the maximum level in 12, hours which is. about two times of that in the uninjected due to the rapid increase in it's, activity. However, in. 48 hours later it became far -less active than the normal. and thereafter by gradual increase restored to the normal level again. 5) Therefore, it may be suggested that the temperature of 32°C. and animus 10°C have possibly an effect upon the hepatic cell mitosis of albino rats, which at first: stimulated, thereafter slightly inhibited, and finally restored to the normal condition. And it is also suggested that the sera of albino rats exposed in the above temperatures have possibly an effect upon the hepatic cell mitosis which, at first more or less is inhibited and followed by the rapid increase in it's activity thereafter, And then it showed the relatively rapid decrease in activity and finally returned to the normal condition. It seems likely that there may possibly be two factors both stimulating and inhibiting the hepatic cell mitosis in the sera of the albino rats exposed in the above mentioned temperatures.

비영리조직의 지배구조 : 이사회를 중심으로

정구현 한국비영리학회 2002 한국비영리학회 학술대회 Vol.- No.-

韓國의 非營利公益法人 活動에 관한 硏究

鄭求鉉 연세대학교 경영연구소 1991 연세경영연구 Vol.28 No.1

농업인의 혁신기술 수용 및 지속적 사용 변수간의 관계

정구현,최영찬,장익훈,박흔동 한국농·산업교육학회 2010 농업교육과 인적자원개발 Vol.42 No.3

This study was conducted to find the critical factors influencing pig farmers' adoption of new technology for pig night soil treatment. Survey for this study was implemented targeting pig farmers in Korea. The research model was built based on DoI(Diffusion of Innovation) and TAM(Technology Acceptance Model) to figure out the effect of individual innovativeness, education support quality and technology support quality on perceived usefulness and perceived ease of use which lead intention to use and user satisfaction. Result from PLS is, first, individual innovativeness, education support quality, and technology support quality work as antecedent variables of perceived usefulness and perceived ease of use. Second, education support quality has positive effect on perceived usefulness of new technology and perceived usefulness has positive effect on user satisfaction of the technology. Finally, this study found that technology support quality doesn't have significant impact on perceived usefulness whereas it has positive effect on perceived ease of use. These results give an implication that development and evaluation of education program require major effort since adoption and intense to use of the new technology in pig farm is most affected by education support quality. 이 연구의 목적은 농업인의 혁신기술 수용 및 기술의 지속적 사용에 미치는 주요한 선행요인을 밝히기 위한 것으로 2002년부터 시작된 ‘양돈분뇨처리기술 시범사업’을 통해 가축분뇨처리 신기술을 도입한 농가에 대해 실시된 설문조사를 바탕으로 수행되었다. 연구모형은 혁신확산이론(DOI)과 기술수용이론(TAM)을 기반으로 도출되었으며 농업인 개인의 특성인 혁신성과 기술보급의 주체이자 변화주도자의 역할을 하고 있는 농업기술센터의 특성인 교육지원품질, 사후 기술지원품질 요인이 기술에 대한 인지된 유용성과 인지된 용이성, 그리고 한 단계 더 나아가 기술에 대한 만족과 지속적인 사용의도에 미치는 영향을 PLS를 이용한 구조방정식 모형 분석을 통해 분석하였다. 분석의 결과는 다음과 같다. 첫째, 혁신확산이론과 기술수용모형을 수정한 정보시스템 지속적 이용 모형에 관한 연구를 바탕으로 신기술의 지속적 이용에 영향을 주는 선행요인으로 개인의 혁신성과 교육지원 품질, 기술지원 품질이 인지된 유용성과 인지된 용이성의 선행변수가 됨을 도출하였다. 둘째, 교육지원품질은 신기술에 대한 유용성 인지에 긍정적인 영향을 미치고, 인지된 유용성은 사용자의 기술만족에 긍정적 영향을 미친다. 또한, 기술만족은 지속적 사용의도에 긍정적 영향을 미치는 것을 실증하였다. 셋째, 기술지원품질은 인지된 유용성에는 유의미한 영향력을 가지지 못하나 인지된 용이성에 긍정적 영향을 미치고 있다. 이와 같은 결과로부터의 주요 시사점은 농가의 신기술 도입 및 지속적 사용의도에 가장 큰 영향을 미치는 요인은 농업기술센터의 교육품질로 앞으로 농업기술센터와 같은 지도기관의 교육프로그램 개발 및 평가에 더 많은 노력이 필요하다는 것을 알 수 있게 해준다.

시간 향유의 양극화와 자본주의적 위기

정구현 교수신문 2016 시간(時間, time) Vol.- No.-

한국 기업의 사회적 책임과 사회공헌활동

정구현 연세대학교 경영연구소 1996 연세경영연구 Vol.33 No.2

Wear Characteristics of Atomic Force Microscopy Tips: A Reivew

정구현 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

Based on the interaction between the extremely sharp tip and the sample, atomic force microscopy (AFM) has been widely utilizedto explore the surface phenomena at the nano-scale. During the AFM measurements such as topographical imaging, forcespectroscopy, and friction loop, the tip is often damaged due to wear, which in turn forms the artifacts in the AFM images and increasethe uncertainties of material properties measured by an AFM. In this paper, based on the numerous studies performed by researchers,the wear characteristics of silicon- and carbon-based tips, and metal coated tips are comprehensively reviewed, including thecharacterization methods and models for tip wear, with an aim to provide an overview of key findings of tip wear that can be usefulfor AFM scientists and engineers.

韓國과 美國간의 直接投資에 관한 硏究

鄭求鉉 경남대학교 극동문제연구소 1987 한국과 국제정치 Vol.3 No.2

사회혁신과 조직혁신

정구현 한국혁신학회 2006 한국혁신학회지 Vol.1 No.1

머신비전을 이용한 나사 머리 성형 펀치의 검사 알고리즘

정구현,정성엽,Jeong, Ku Hyeon,Chung, Seong Youb 한국교통대학교 융복합기술연구소 2013 융ㆍ복합기술연구소 논문집 Vol.3 No.2

This paper proposes a vision-based inspection algorithm for a punch which is used when forming the head of the small screws. To maintain good quality of punch, the precise inspection of its dimension and the depth of the punch head is important. A CCD camera and an illumination dome light are used to measure its dimensions. And a structured line laser is also used to measure the depth of the punch head. Resolution and visible area depend on setup between laser and camera which is determined using CAD-based simulation. The proposed method is successfully evaluated using experiment on #2 punch.