공동골격을 가진 개방셀 세라믹스의 상대밀도와 압축강도 모델

정한남,현상훈 한국세라믹학회 1997 한국세라믹학회지 Vol.34 No.11

A model for predicting the relative density and the compressive strength of open-cell ceramics with three-dimensional network structure was proposed through the interpretation of their macrostructure and fracture mechanics. The equation predicting the relative density was derived under the assumption that the open-cell structure was a periodic array of the tetrakaidecahedron unit cell consisting of cylindrical struts containing the internal hollow with the shape of a triangular prism. The model for compressive strength of open-cell ceramics with the hollow strut was also developed by modifying conventional model which based on fracture behavior of them subjected to the compressive stress. Both the relative density and the compressive strength were expressed in terms of the ratio of the strut diameter to the length together with the ratio of the hollow size to the strut diameter. The proposed model for the relative density and the compressive strength of the alumina-zirconia composite with open-cell structure were accorded well with the experimental values, whereas Gibson-Ashby and Zhang's model did not show such a good agreement.

개방셀 세라믹스의 압축강도에 대한 제조공정변수 및 미세구조의 영향

정한남,현상훈 한국세라믹학회 1999 한국세라믹학회지 Vol.36 No.9

The effect of fabrication variables and microstructures on the compressive strength of open cell alumina zirconia and silicon nitride ceramics fabricated by polymeric sponge method was investigated. Bulk density and compressive strength of open cell ceramics were mainly affected by coating characteristics of ceramic slurry on polymeric sponge that controlled a shape thickness and defect of the struts. Sintering temperature was optimized for enhancement of strut strength and compressive strength of open cell ceramics. Relative density and compressive strength behaviors were relatively well matched with the predicted values. Open cell ceramics of lower relative density below 0.1 prepared by first relatively well matched with the predicted values. Open cell ceramics of lower relative density below 0.1 prepared by first coating of ceramic slurry had thin triangular prismatic struts that were often broken or longitudinally cracked. With an application of second coating of slurry shape of struts was transformed into thickner cylindrical one and defects in struts were healed but the relative density increased over 0.2 Open cell zirconia had both the highest bulk density and compressive strength and alumina had the lowest compressive strength while silicon nitrides showed relatively high compressive strength and the lowest density. Based upon the analysis open cell silicon nitride was expected to be one of potential structural ceramics with light weight.

오가피 첨가량에 따른 약주의 품질 특성

김기식, 윤향식, 한남수, 정헌상, 노재관, 노창우 충북대학교 농업과학기술연구소 2010 農業科學硏究 Vol.26 No.2

-본문참고-

젊은 남성에게서 재발한 다발성 간 내 국소 결절성 과형성 1예

정은 ( Eun Chung ),박정화 ( Chung Hwa Park ),김진아 ( Jean A Kim ),한남익 ( Nam Ik Han ),이영석 ( Young Sok Lee ),최호중 ( Ho Joong Choi ),배시현 ( Si Hyun Bae ),박일영 ( Il Young Park ) 대한소화기학회 2014 대한소화기학회지 Vol.64 No.1

Focal nodular hyperplasia (FNH) is the second most common benign hepatic tumor that is usually found in women. Diagnosis of FNH mainly depends on imaging studies such as color Doppler flow imaging, computed tomography, and magnetic resonance imaging. It is characterized by the presence of stellate central scar and is nowadays incidentally diagnosed with increasing frequency due to advances in radiologic imaging technique. FNH typically presents as a single lesion in 70% of cases and generally does not progress to malignancy or recur after resection. Herein, we report a case of a young male patient with recurrent multiple FNH who underwent surgical resection for presumed hepatic adenoma on computed tomography. (Korean J Gastroenterol 2014;64:49-53)

원발성 맥락막 악성 흑색종 1예

정하상(Ha Sang Chung),양한남(Han Nam Yang),유중하(Joong Ha Yoo) 대한안과학회 1984 대한안과학회지 Vol.25 No.4

전이성 안내염증 1예

정하상,양한남,문연성,김무웅 중앙대부설한국의과학연구소 1985 한국의과학 Vol.17 No.1

초등학생의 성취목표성향에 따른 성공수행 피드백이 운동기능학습에 미치는 영향

박종태,정성우,한남익 한국초등체육학회 2015 한국초등체육학회지 Vol.21 No.3

본 연구는 초등학교 5, 6학년 남자 아동의 족구 패스동작 기능학습에서 성취목표성향의 하위요인인 과제성향이 높은 집단(과제성향), 자기성향이 높은 집단(자기성향) 그리고 과제성향과 자기성향이 모두 높은 집단(과제·자기성 향)에 따른 성공수행 피드백과 실패수행 피드백의 효과를 검증하는데 그 목적이 있다. 이러한 연구 목적을 달성 하기 위해 B광역시에 소재한 B초등학교 5, 6학년 남학생 128명을 대상으로 성취목표성향질문지와 족구 패스동작 의 수행점수 결과를 비교 분석하여 다음과 같은 결론을 얻었다. 첫째, 습득단계에서 성공수행 피드백 집단이 실 패수행 피드백 집단보다 유의하게 높은 수행 점수를 나타내었으나 성취목표성향에 따른 차이는 나타나지 않았다. 둘째, 파지단계에서 성취목표성향의 과제성향집단과 과제·자기성향집단이 자기성향집단보다 유의하게 높은 수행 점수를 나타내었다. 또한 성공수행 피드백 집단이 실패수행 피드백 집단보다 유의하게 높은 수행점수를 나타내었 다. 셋째, 초등학생의 족구 패스 기능학습에서 과제성향집단, 과제·자기성향집단이 성공수행 피드백을 제공받을 때 가장 효과적인 수행성적을 나타내었다. The purpose of this study was to examine the distinct influences of feedback after good trials and poor trials on elementary school student' jokgu pass skill learning and to provide more effective methods for teaching various student who have different achievement goal orientations. The subjects were selected from the B elementary school in Busan metropolitan city. The test subjects were 5th and 6th grade elementary school students(Males, n=128). The test subjects constituted a high - task goal orientation group(24 feedback after good trials students, 24 feedback after poor trials students), a high - ego goal orientation group(16 feedback after good trials students, 16 feedback after poor trials students) and a high - task · ego goal orientation group(22 feedback after good trials students, 22 feedback after poor trials students). The task used in this research was pass skill of jokgu. The data analysis of acquisition phase and retention tests were carried out under 3(task/ego/task·ego goal orientation group)×2(feedback after good/poor group)×6(block) or 3(task/ego/task·ego goal orientation group)×2(feedback after good/poor group)×2(block) factorial design with repeated measures on the last factor. The following results were reached by analysing the test data. (a) feedback after good trials groups were more effective than feedback after poor trials students at acquisition phase retention test. (b) a high - task goal orientation and task · ego goal orientation groups were more effective than high - ego goal orientation group at retention test. The study proves that high - task goal/task · ego orientation and feedback after good trials are important factor on skill learning of jokgu pass.

Flory-Huggins 식을 이용한 고분자 흡착 모델 및 전분의 흡착

현상훈,정한남 한국세라믹학회 1986 한국세라믹학회지 Vol.23 No.3

The equilibrium dsorption of starch on activated alumina and kaolin was studied to provide the fundamental data for investigating the effect of polymer adsorption on the flocculation of solid particles. The new polymer adsor-ption model(PAH-FH) predicting the adsorption equilibria of polymers on the solid surface has been developed using the solution theory and the concepts of Gibbs dividing surface in conjunction with the Flory-Huggins eq-uation and the adsorption behaviors of polymers were examined by this model The accurate adsorption equilibrium data of starch on alumina and kaolin were determined within the tempera-ture range of 298-318K by the ignition loss method. Using these experimenta data the model developed in this study was evaluated. It was shown that this model could predict the adsorption isotherm more accura-tely than the Langmuir model as well as could describe the characteristics of the adsorption equilibria through model parameters.

Zirconia성형체의 미세구조와 콜로이드/계면변수와의 상관관계에 대한 분석

장현명,한규호,이기강,정한남 한국세라믹학회 1990 한국세라믹학회지 Vol.27 No.1

The green microstructure and sintering behavior of ZrO2 were analyzed in terms of kinetic stability (measured by the stability ratio ; W) and interfacial characteristics of colloidal suspension. Green density and the most frequent pore radius(MFPR) of green body were directly correlated with the stability ratio. These observations were explained using a concept of the critical stability ratio(Wc) and the potential energy of two interacting particles in colloidal suspension. Analysis of the data also indicates that the potential energy barrier between two interacting colloid particles should be higher than its critical value for a fabrication of ZrO2 green body with dense and uniform microstructure. Besides, we have successfully applied a concept of the donoracceptor interaction to increase the kinetic stability of ZrO2 slip and density of green body.

콜로이드/계면변수가 Zirconia의 치밀화와 기공제거에 미치는 영향

장현명,한규호,이기강,정한남 한국세라믹학회 1990 한국세라믹학회지 Vol.27 No.2

The sintering characteristics of ZrO2 were analyzed in terms of pore microstructure and kinetics of pore elimination. The pore structue of the ZrO2 sample prepared from colloid suspension was characterized by three distinct types of pores ; intradomain, interdomain, and intergglomerate pores. Sintering data at 1600$^{\circ}C$ showed that pores larger than a certain critical size(∼3$\mu\textrm{m}$) were difficult to remove, and this was analyzed in terms of the interagglomerate pore formed from the suspension under the condition of low kinetic stability, that is, the stability ratio smaller than its critical value. A theoretical equation for densification rate was derived and was applied to the densification rate of the ZrO2 polycrystalline body containging both the matrix(the 1st-generation) pores and the interagglomerate (the 2nd-generation) pores under the condition of slow grain growth.