蓄熱用 TMA 包接化合物의 熱物性에 關한 實驗 硏究(Ⅰ)

최영범,한영옥,하옥남,김병철,김진흥 조선대학교 동력자원연구소 1996 動力資源硏究所誌 Vol.18 No.2

This paper presents the test-tube experimental results of thermal properties of TMA clathrate compounds for latent heat storage applications. The results are : ⅰ) subcooling in TMA clathrate compound is the lower than water, ⅱ) Phase change temperature in TMA clathrate compound is the higher than water. ⅲ) Latent heat of 25wt% TMA clathrate compounds of 220.4kJ/㎏K appear to be maximum. ⅳ) Comparing with water, volume of TMA clathrate compounds decreased as the phase change. ⅴ) TMA clathrate compounds precipitated because of increase of density as phase change. Thus, TMA clathrate compounds are found to be the promising compounds for the heat storage from the viewpoint of thermal property.

하지방사통을 동반한 성인 협부결손성 요추전방전위증의 후방요추간유합술 및 추경나사고정술후 추적결과

최철,김근수,최하영,김철진,김형일,이정청 대한신경외과학회 1999 Journal of Korean neurosurgical society Vol.28 No.4

백서에서 실험적 치아이동시 치조골 흡수에 미치는 Bisphosphonate의 영향 : 생화학적 및 조직학적 관찰 Biochemical & Histological Observations

최진휴,김종철 대한치과교정학회 1999 대한치과교정학회지 Vol.29 No.1

백서에서 실험적 치아 이동시 bisphosphonate가 파골세포의 형성에 미치는 영향과 골 흡수 억제기전을 규명하고 독성유무를 알아보고자 하였다. 체중 260-350g의 웅성 백서 87마리를 정상군(장치비장착 + 0.9% NaCl), 대조군(장치장착 _ 0.9% NaCl) 및 장치장착후 bisphosphonate 투여군(0.8mg, 4 mg, 20 mg, 및 100mg/kg) 으로 분류하였다. 상악 좌측 제1대구치를 근심으로 치아이동이 일어나도록 50-70g의 교정력을 가하고, 교정장치 장착후 1일, 3일 및 7일째에 혈청 acid phosphatase와 lactate dehydrogenase (LDH)의 활성도를 측정하고, 또한 제1대구치를 포함한 상악골일부에서 파골세포수 및 골흡수 정도를 조직학적으로 관찰하여 다음과 같은 성적을 얻었다. 1. Acid phosphatase 활성도는 장치후 1일째와 3일째에 대조군과 bisphosphonate 투여군에 서 모두 정상군에 비해 2-3배 높았으나, 7일째에는 정상군과 유의한 차이를 보이지 않았다. 2. LDH활성도는 bisphosphonate 4 mg과 20mg/kg 투여군에서 전 실험기간에 걸쳐 증가된 양상을 보였으나 0.8mg과 100mg/kg 투여군에서는 유의한 차이를 나타내지 않았다. 3. 골흡수는 장치후 1일째에 대조군과 bisphosphonate 투여군에서 모두 관찰되지 않았으나, 3일 이후에 나타난 7일째가지 지속되었다. Bisphosphonate 4, 20 및 100mg/kg 군에서의 골흡수정도는 3일째에는 대조군에 비해 미약하였으나 7일째에는 대조군과 유사하게 나타났다. 4. 파골세포는 1일째에 대조군이나 bisphosphonate 투여군 모두에서 거의 관찰할 수 없었다. 3일째에 대조군에서는 파골세포가 다량 출현하였으나 bisphosphonate 투여군에서는 약물의 용량이 증가함에 따라 감소하여 나타났다. 이상의 결과로 실험적 치아이동시 파골세포의 형성억제가 bisphosphonate에 의한 골흡수억제기전이 아님을 알 수 있었고, bisphosphonate는 투여량이 증가에 따른 뚜렷한 세포독성은 관찰되지 않았으며, 골흡수 억제효과를 지속시키기 위해서는 약물이 반복적으로 투여되어야 할 필요가 있음이 시사되었다. This study was performed to examine the effect of bisphosphonate, an inhibitor of bone resorption, on the formation of osteoclast and bone resorption during experimental tooth movement. Whether bisphosphonate has a cytotoxity in high dose was also examined. Eighty-seven male Sprague-Dawley rats, weighing 260-350g, were classified into normal (no appliance + 0.9% NaCl), control (appliance + 0.9% NaCl) and four bisphosphonate-treated (appliance + 0.8, 4, 20, or 100mg/kg) groups. The maxillary left first molar was moved mesially with the tipping movement using 5-70g of force. Bisphosphonate(etidronate disodium) was injected intraperitoneally with a dose of 0.8, 4, 20 or 100mg/kg simultaneously with the application of the orthodontic force. They were killed at day 1, 3 or 7 after the application of the orthodontic force. The activities of serum acid phosphatase and lactate dehydrogenase (LDH) were assayed, and osteoclasts and the degree of bone resorption were examined histologically. The results obtained were as follows: 1. Acid phosphatase activities were significantly higher in the appliance groups, both control and bisphosphonate-treated (4, 20, and 100 mg/kg) groups, at days 1 and 3 than these in normal. At day 1, bisphosphonate-treated(4, 20mg/kg) groups showed even higher acid phosphatase than control. However, at day 7, no significant difference was noted between the control and bisphosphonate-treated groups. 2. LDH activities in the 4, 20mg/kg bisphosphonate-treated groups were increased during the experimental periods examined, but there were no significant differences in the 0.8, 100mg/kg bisphosphonate-treated groups. 3. There was no bone resorption at day, 1, but severe bone resorption was observed at days 3 and 7 in the control. Bone resorption was reduced by bisphosphonate-treatment at day 3. Bone resorption observed at day 7 was similar between the control and bisphosphonate-treated groups. 4. Few osteoclasts were observed at the alveolar bone in the control and bisphosphonate-treated groups at day 1. At day 3, numerous osteoclasts were shown in the control, the degree of which was reduced in bisphosphonate-treated groups. These results suggest that the inhibition of the osteoclast formation was not the mechanism of bone resorption by the bisphosphonate-treatment during experimenal tooth movement. There was no distinct cytotoxicity with a high dose of bisphosphonate. And the drug should be administrated repeatedly to maintain the inhibitory effect of bone resorption.

부적절한 예방화학요법 후 지연 발현된 Plasmodium vivax 말라리아 1 예

최수철,장상필,김상화,서환조,서진태,김구엽 대한내과학회 1998 대한내과학회지 Vol.54 No.3

Malaria is the world's most important parasitic infection. Although it has been erw5cated from temperate zones including Korea, increasing numbers of travellers visit tropical malarious countries and imported malaria becomes important medical problem in the developed countries. In Korea with increasing travellers to malaria-endemic area, the incidence of imported malaria shows rising tendency same as the developed countries. It becomes important to personal general personal protective measures and chemoprophylaxis to trevellers, when employed in appropriate manner, that can be highly effective in preventing malaria. We recently experienced a case of in Plasmodium vivax malaria with delayed manifestations due to inadequate chemoprophylaxis. A 53-year-old woman with history of trevel to East Africa 4 months ago and chief complaint of fever was diagnosed as tertian malaria. She had irregularly taken prophylatic antimalarial during travel and had not taken it after return but should have taken it at least 4 weeks after return.

조명광원의 색온도와 조도 및 스펙트럼 측정

최대욱,박성진,임춘우,석성수,오철한 慶北大學校 師範大學 科學敎育硏究所 1999 科學敎育硏究誌 Vol.23 No.-

The peak wavelength and temperatures of W-Halogen standard light source were measured by using the modified Wien's Law. In the case of graybody, the emissivity ε should be taken into account in using the Wien's Law. In the experiment, PDA spectroscope was used for the measurement of peak wavelength of intensity distribution of spectrum. As the current of light source increases from 5A to 7.4A, the peak wavelength of intensity distribution of the spectrum decreased from 717nm to 690nm, and temperature increased from 3127K to 3330K. Illuminations of three-wavelength lamps and light source were also measured. It was found that irradiation spectrum of those three-wavelength lamps are not coincident to blue(450nm), green(550nm) and red(610nm).

혼합유의 이화학적 특성에 관한 연구

최성희,박철진,오성기 경희대학교 부설 식량자원개발연구소 1992 硏究論文集 Vol.13 No.-

The objective of this study was to investigate the physicochemical characteristics of binary and ternary oil systems. Materials used in this experiment were four edible oils i. e. sesame, soybean, red-pepper seed and Sancho (Zanthoxylum schinifolium) seed oils. The physicochemical properties of mixed oils, as well as the inductive period of oxidation, were measured. The results obtained are as follows : 1. The optimum mixing ratios of sesame oil with each of soybean, red-pepper seed and Sancho seed oils, which still maintained a characteristic sesame oil flavor, were 1 : 3,1 : 0.5 and 1 : 0.5, respectively. 2. Sesame, soybean and red-pepper seed oils showed low acid and peroxide values. In contrast, however, Sancho seed oil showed the very high values, and acid, peroxide and TBA values were 17. 4, 28.6 and 1.8, respectively, Among the oils, soybean oil gave the longest induction period of oxidation and Sancho seed oils the shortest, and the induction period was increased in order of Sanch seed, red-pepper seed, sesame and soybean oils. 3. Binary oil system such as a mixed oil of seasame oil and each of soybean and red-pepper seed oils did not show any significant change in acid, peroxide and TBA values, but a mixed oil of sesame oil and Sancho seed oils gave a drastic change in acid (7.2), peroxide (12.3), and TBA (0.2) values. All the binary oil systems extended their induction periods of oxidation. 4. In ternary oil system, a mixed oil of sesame, soybean and red-pepper sees oils did not show any significant change in acid and peroxide values. In contrast, however, mixed oils of sesame, red -pepper seed and Sancho seed oils in the ratios of 1 : 1 : 1 and 4.5, 8.9 and 0.13 in the ratio of 1 : 0.25 : 0.25, respectively. All the ternary oil systems also extended the induction period of oxidation.

흰쥐 안면신경핵 세포의 전기생리학적 및 형태학적 특성

최병주,조진화,배용철,김영진 大韓小兒齒科學會 2000 大韓小兒齒科學會誌 Vol.27 No.3

흰쥐의 안면신경핵을 구성하는 신경세포들의 시냅스 연결 양태 및 세포막 특성을 규명하기 위해 in vivo 필드전위 및 세포내 전위 측정법을 이용하여 전기생리적 반응을 관찰하였다. 말초 안면신경 분지를 역행성으로 전기자극시 자극세기에 비례하여 전위의 크기가 증가되었고 필드 전위의 양태는 두 가지 반응으로 나타났는데 전기자극 직후 1ms 부근에서 정점을 나타내는 양태와 이와 더불어 7~8ms 부근에서 후기 정점을 동반하는 양태가 있었다. 안면신경핵은 염색시 내측, 배외측, 중간측 및 외측등 4부분의 소핵으로 구분되었다. Neurobiotin으로 채워진 단일 신경세포를 형태학적으로 재구축하였는데 세포체는 추체형태를 나타내었고 주 수상돌기는 모든 방향으로 뻗어져 있었고 각 수상돌기의 영역은 해당 소핵 내에 한정되어 있었다. 일련의 과분극 전류(-1.2~+1.2nA)를 세포내에 가하였을 때 동반되는 세포내 전위변화를 입력저항 값으로 계산하였을 때 그 기울기가 직선형으로 나타났다. 탈분극 전류를 세포내 주입시 지속적인 활동성 전위가 나타났으며 전류의 크기에 비례하여 각 전위의 개수가 증가하였고 spike-빈도 적응 현상이 나타났다. 그러나 시간 의존성 내향성 정류현상은 관찰되지 않았고 anodal break excitation이 나타났다. 이상의 실험결과로 보아 안면신경핵을 구성하고 있는 세포들 사이의 시냅스는 다양한 형태로 존재할 가능성이 있다고 사료되며 이들 시냅스간의 변화를 통하여 안면 신경마비, 반쪽 안면 경련, hypoglossal-facial anastomosis등에서 나타날 수 있는 임상적 신경성 증상 기전을 설명할 수 있을 것으로 여겨진다. 주요어 : 안면신경핵, 시냅스, 신경세포막 특성, 안면신경마비, 반쪽 안면 경련 This study used in vivo intracellular and extracellular fIeld potential recording to evaluate the intrinsic membrane properties and connection pattern within facial nucleus. 1.There were four subdivisions of medial, intermediate, lateral, and dorsolateral in facial nucleus. 2.Principal cells in the facial nucleus was recorded from and filled with neurobiotin in anesthetized rats. The extent of their dendrites and the characteristics of cell body were examined. 3.Principal cells had a large amplitude action potential and afterhyperpolarization was followed a single action potential. 4.The response from facial motonucleus to electrical stimulation of the facial nerve was mainly a monophasic wave, with a latency of 1 msec, which was assumed to reflect antidromic activation of facial motoneurons. In some of rats the response in addition showed late components at a latency of about 7-8 msec, but its amplitude was small. 5.Mest of cells exhibited accommodation of spike discharge upon depolarization of membrane by 0.8 nA for 400 ms. Our results support the hypothesis that there normally are weak connections between different parts of the facial motonucleus to explain pathophysiology of hemifacial spasm and facial nerve paralysis.

Molar Uprighting Spring에 의해 발생되는 치조골내의 응력분포에 관한 광탄성학적 연구

최진휴,김종철 전남대학교 치과대학 1990 전남치대논문집 Vol.2 No.1

This study was performed to analyze the effects of forces to the alveolar bone by various molar uprighting spring such as helical uprighting spring, T-loop spring, Modified T-loop spring and open coil spring. The simplified two-dimensional photoelastic model was constructed with a lower left posterior quadrant containing the second molar, the first and second premolars and the canine, with the first molar missing. Several molar uprighting springs were fabricated from 0.017 by 0.022 inch blue Elgiloy and applied to the photoelastic model. Two-dimensional photoelastic stress analysis was performed, and the stress distribution was recorded by photography. The results obtained were as follows ; 1. In all the kinds of the springs, the center of rotation of the mandibular second molar was observed at the apical 1/5-1/6 between the alveolar crest and the root apex. 2. In all the kinds of the spring, the stress induced in the mesial root surface of the manibular second molar was relatively homogeneous but there was some difference in the magnitude of the stress. 3. In the kinds of the springs, the distal crown tipping moment of the second molar was increased in turn as open coil spring, helical uprighting spring, T-loop spring, and modified T-loop spring. 4. The largest extrusive force was occured in the T-loop spring, intrusive force was occured in Modified T-loop spring only, and the largest distal tipping force was occured in open coil spring. 5. In the T-loop spring with activation, the stress induced in the mesial root surface of the second molar was increased gradually from the root apex to the alveolar crest and highly concentrated in the alveolar crest.

전산화단층사진을 이용한 하악골 비대칭 환자의 저작근 평가

최순철,이선복,이진구,이원진,허민석,이삼선 大韓口腔顎顔面 放射線學會 2004 Imaging Science in Dentistry Vol.34 No.1

Purpose : To compare the size of the masseter and lateral pterygoid muscle between the affected and the unaffected side of the patients who have the chief complaints of the mandibular asymmetry. Materials and Methods : Twenty two patients (male: 4, female: 18, average age: 21.3 year-old) were radiographed using posterior-anterior (P-A) cephalography and computed tomography (CT). On P-A cephalography, the degree of deviation was determined by the distance from the mentum to the vertical reference line through the crista galli and the anterior nasal spine. On the scanned tracing papers of the maximum cross-sectional area of the masseter and lateral pterygoid muscle using axial CT images, the pixel number was measured. The ratio of the affected : unaffected sides were obtained. For the masseter and lateral pterygoid muscle, the relationship between the muscular volume and degree of skeletal hypoplasia was studied. Results : The half cases showed no skeletal asymmetry. The lateral pterygoid muscle of the affected side was larger significantly than unaffected side (p<0.05). However, there was no significant difference between two sides in the cases of skeletal asymmetry. There was only significant difference in the cases without skeletal asymmetry (p<0.05). Conclusions : To some extent, the slight mandibular hypoplasia could affect the growth of some masticatory muscles.

크롬-망간鋼에서 析出된 複合炭化物의 粗大化 特性에 관한 硏究

崔鎭源,李相允,安哲佑 東亞大學校 大學院 1987 大學院論文集 Vol.12 No.-

This study has been carried out to investigate into the Ostwald Ripening behaviors of comples carbide particles precipitated in Cr-Mn steel during spheroidizing treatment at a range of temperature 650℃ to 710℃ after standarding the initial particle size distribution. The results obtained from the experiment are as follows; 1. Optical micrographs have shown that the precipitated particles mostly grow along grain boundaries with their shapes being irregular and that particles within the ferrite matrix appear to be small spheres. 2. Average particle size measurements have presented that a reciprocal of the slopes of three straight lines obtained from the relation between the log of average particle radius and the log of spheroidiaing time for 650℃, 680℃ and 710℃ approaches a value of 3.5 and that the growth of complex carbide particles occurs by a diffusion controlled mechanism combined with volume diffusion and grain boundary diffusion. 3. In has been found from the measured values for the average particle radius and the number of particles per unit volume that the average value of activation energy is 48.3Kcal/mole, which shows that the coarsening of complex carbide particles is governed by the interdiffusion mechanism of Fe, C, Cr and Mn atoms. 4. X-ray diffraction analysis has shown that the complex carbide particles precipitated during spheroidizing treatment are of two types, (Fe, Cr, Mn)₃C and (Fe, Cr, Mn)? C₃. 5. Experimentally measured particle size distribution curves approach the steady state distribution curve obtained for volume diffusion but their width and height are relatively broader and lower.