이기수 한국대학교육협의회 회장 인터뷰

이기수,편집부 한국교육과정평가원 2010 교육광장 Vol.36 No.-

어음채무자의 면책

이기수 한국사법행정학회 1988 사법행정 Vol.29 No.7

공정거래법 심결사례 해설 및 평석

이기수 한국공정경쟁연합회 1997 경쟁저널 Vol.26 No.-

공정거래법 심결사례 해설 및 평석

이기수 한국공정경쟁연합회 1998 경쟁저널 Vol.40 No.-

불소가 산부식된 법랑질의 재석회화에 미치는 영향에 관한 연구

김진한,이기수 대한치과교정학회 1996 대한치과교정학회지 Vol.26 No.4

치과교정장치의 장착을 위하여 치아법랑질표면을 산부식하는 것은 일반화된 술식이며, 산부식된 법랑질표면은 재석회화되어 자연적으로 정상상태를 회복하는 연구보고되어 왔다. 이 연구의 목적은 산부식된 법랑질 표면의 재석화에 불소가 미치는 영향을 실험적으로 관찰하여 재석회화의 일면을 구명하는데 있다. 교정치료목적으로 발거한 사람 제1소구치 치관을, 불소함유 석회화용액과 불소무함유 석회화용액에 12시간, 1일, 3일, 7일, 14일, 28일, 42일간 담구어 보관한후, 법랑질표면의 미세경도측정과 주사전자현미경관찰을 통하여 법랑질 표면의 변화들을 경시적으로 관찰하여 다음의 결과를 얻었다. 1) 표면미세경도는 불소함유 여부에 관계없이 시간경과에 따라 증가하였으며, 불소함유군은 12시간부터, 불소무함유군은 3일 경과후부터 현저히 증가하였으나, 시간경과에 따라 그 차이는 감소하였다. 2) 주사전자현미경관찰에서 불소함유용군은 12시간후부터 법랑질표면에 침상물질이 침착되기 시작하여 42일 후에는 편평한 표면으로 되었으나, 불소무함유용군은 전실험기간동안 산부식직후보다 약간 더 거칠어졌으나, 산부식된 법랑질표면이 그대로 관찰되었다. 이상의 결과로부터 불소는 산부식된 법랑질표면의 재석회화 시기를 앞당기는 효과가 있으며, 재석회화의 소요시간도 단축하는 효과가 있음이 확인하였다. Remineralization of acid-etched enamel across the time has been one of the curiosities in the context of the orthodontic biomechanics(Arends J. et al., IRL Press, 1, 1985), nevertheless, is so far controversial. It was the aim of this study to observe the remineralization patterns of acid-etched enamel across the time and whether the existence of fluoride might carry out any modifications. The intact buccal surfaces of the first bicuspids which was extracted for orthodontic treatment were ground smooth, and etched with a 38w/w% phosphoric acid for 60 seconds. The surface was observed by the scanning electron microscope and surface microhardness was measured after immersion in the fluoride or non-fluoride containing remineralizing solution for 0 hour, 12 hours, 1 day, 3 days, 7 days, 14 days, 28 days, and 42 days. The following results and conclusions were drawn; 1. Surface microhardness increased in both fluoride containing and non-fluoride containing solution group with time lapse. 2. In fluoride containing solution group, the surface microhardness sharply increased at the 12 hours group, on the other hand, surface microhardness increased at 3 days in non-fluoride containing solution group. 3. The difference in microhardness value between two groups manifested gradual decrease. 4. Scanning electron microphotographs disclosed that the fluoride containing solution group generated spiculate substances in the 12 hours group, which was increased in number and size with time lapse. 7days later, spherical composure was began to be produced. The spiculate substances so much increased in number that the etched enamel surface looked like flat in 42 days. 5. In non fluoride-containing solution group, there was no surface change at 42 days, perceivable in scanning electron microphotographs which could be defined as remineralization though the surface was a little rougher than the incipient etched surface. These results demonstrate that the action of the fluoride is exceedingly pertinent in the remineralization of acid-etched enamel and the remineralization process goes uninterruptedly with time lapse.

화학중합형 및 광중합형 레진접착제가 금속 및 도재브라켓의 전단결합강도에 미치는 영향

윤덕상,이기수 대한치과교정학회 1994 대한치과교정학회지 Vol.24 No.1

This study was designed for comparison of shear bond strengths and failure patterns of four experimental groups which combinated mesh-backed metal brackets and texture based ceramic brackets(Transcend series 2000(TM)) with chemically cured resin (Mono Lok2(TM)) and visible light cured resin (Transbond(TM)). Brackets were bonded on the extracted human bicuspids, after etching them by manufacturer's recommand, and the shear bond strengths were measured on the Instron machine 24 hrs passed in the 37℃ water bath. The results were as follows. 1. Ceramic brackets, transcend series 2000(TM), bonded with MonoLok2(TM) showed statistically higher shear bond strength than mesh-backed metal brackets bonded with MonoLok2(TM). 2. There was no significant difference in shear bond strengths between metal and ceramic brackets bonded with Transbond(TM). 3. Ceramic brackets bonded with both Transbond(TM) and MonoLok2(TM) showed primarily fractures between brackets adhesive interface. 4. Enamel crack was not found in anyone specimen.

법랑질표면에서 폴리아크릴산용액 농도와 황산이온 농도가 결정형성에 미치는 영향

김주형,이기수 대한치과교정학회 1998 대한치과교정학회지 Vol.28 No.5

교정장치의 직접부착을 위하여 일반적으로 사용되고 있는 산부식법의 대체가능 방법중 하나는 결정형성법이며, 폴리아크릴산과 황산이온은 결정형성액의 주요 물질로 알려져 왔다. 이 연구는 황산이온농도와 폴리아크릴산의 농도변화가 결정형성에 미치는 영향을 관찰하여 결정형성용액에 관한 기초자료를 획득하기 위하여 시행되었다. 분자량 5,000의 폴리아크릴산을 10%, 20%, 30% 및 40%의 용액으로 만들고, 각각의 용액에 황산이온 농도가 0.1M, 0.2M, 0.3M, 0.5M 및 1.0M이 포함되는 총 20가지의 실험용 결정형성용액을 제조하고, 이들을 법랑표면에 60초간 반응시킨 후, 주사전자현미경 사진을 촬영하여 결정 피복도, 결정 길이 및 결정형태 분포의 균일성을 평가하여 다음과 같은 결론을 얻었다. 1. 폴리아크릴산 용액은 법랑질 표면을 경미하게 부식시켰으며, 농도에 따른 부식효과의 차이는 없었다. 2. 폴리아크릴산의 농도는 결정형성에 적은 영향을 미쳤다. 특히 20% - 40%사이의 폴리아크릴산 용액은 결정형성에 영향을 미치지 않았다. 3. 황산이온 농도는 결정형성의 주요인자이다. 0.2M이상의 황산이온이 포함된 폴리아크릴산 용액에서 결정이 형성되었다. 4. 20%∼40% 폴리아크릴산 용액에 포함된 황산이온농도가 결정 피복도에 미치는 영향은 황산이온 농도가 어느한도까지 증가하면 결정 피복도도 증가하나 그 이상에서는 감소하는 경향으로 나타났다. 이 실험에서는 0.5M 황산이온이 포함된 실험용액이 가장 높은 결정 피복도를 나타냈으며, 최대의 결정 피복도를 나타내는 황산이온 농도는 0.5M, 혹은 0.5M에서 1.0M사이에 있을 것으로 추정되었다. 5. 폴리아크릴산 용액내의 황산이온 농도가 증가할수록 결정길이는 작아지는 경향을 보였다. 6. 폴리아크릴산 용액내의 황산이온 농도는 결정 형태의 분포에 영향을 미친다. 황산이온의 농도가 낮을수록 spherulitic형 배열의 결정형성이 증가하고, 황산이온농도가 증가하면 무정형 배열의 결정형성이 증가하는 경향을 보였다. 7. 이 연구에서 가장 양호한 실험용 결정형성용액은 0.5M 황산이온이 포함된 30% 폴리아크릴산 용액이었다. This study was designed to observe the effects of various concentration of polyacrylic acid containing different concentration of sulfate ion on the crystal formation on the enamel surface. Experimental crystal growth solutions were made of 10%, 20%, 30%, and 40% polyacrylic acid(molecular weight, 5,000)solutions which contacted for 60seconds with these solutions, washed for 15 seconds, dried, and then the crystal topography on the enamel surface was observed under the scanning election microscope. The crystal topography were evaluated on the SEM photographs by degree of crystal coverage, crystal length, and consistency of crystal morphology, and conclusions were as the follows. 1. Polyacrylic acid solution etched slightly the enamel surface, and the difference of etching effect by its concentration was not observed. 2. The effect of concentration of ployacrylic acid on the crystal formation was less, especially that of 20%-40% polyacrylic acid. was almost not different. 3. Concentration of the sulfate ion was a determinant factor in precipitating crystals on the enamel. The experimental crystal growth solutions containing 0.1M sulfate ion did not make crystal formation but those containing over 0.2M sulfate ion did. 4. The degree of crystal coverage showed a tendency to increase and then decrease according to the concentration of sulfate ion in the 20%-40% polyacrylic acid. The experimental solutions containing 0.5 M sulfate ion showed the peak of degree of crystal coverage. 5. The crystal length showed a tendency to decrease by increment of sulfate ion in the polyacrylic acid solution. 6. There was a tendency to increase the frequency of random arrangement of short crystals when increasing the concentration of sulfate ion in the polyacrylic acid solution. The lower concentration of sulfate ion in the plyacrylic acid solutions tended to make spherulitic arrangement of crystals, the higher concentration of sulfate ion, the more random arrangement of crystals, The experimental solutions containing 0.5M sulfate ion showed more spherulitic arrangement than random arrangement of crystals. 7. The best one of these experimental crystal growth solutions was 30%polyacrylic acid solution containing 0.5M sulfate ion.

공정거래법(약관규제법) 심결사례 해설 및 평석

이기수 한국공정경쟁연합회 1998 경쟁저널 Vol.32 No.-

교육용 Programmable Controller의 설계 및 제작에 관한 연구

李祥宰,李琦秀 金烏工科大學校 1986 論文集 Vol.7 No.-

In this paper, we designed and abricated the small-size programmable controller(PC) for On-Off cintroller application, which has 32input/output orts, 32 internal relays, and the user memory of 2Kbytes. For the good understanding of the basic operational principles of the PC hardware and the easy troubleshooting, we constructed the entire hardware based on modular design of several functional blocks. The software of this system was prepared with machine code through the ladder-diagram method. The elevator system was modeled and simulated for the experiments, and the results were in good agreement with the theoritical expects.

공정거래법 심결사례 해설 및 평석

이기수 한국공정경쟁연합회 1998 경쟁저널 Vol.35 No.-