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.

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.

入口에 案內管이 있는 開放型 熱 사이폰에 關한 硏究

최인규,이진호,김철주 연세대학교 대학원 1976 延世論叢 Vol.13 No.2

The experimental study was carried out to investigate the characteristics of the flow fluctuation pheonomena, which occurred in the transition process from the impeded flow regime to the boundary layer flow regime in awl open thermosyphon by placing flow guides at the center of the orifice inlet where fluctuation occurred. The diameter and length of the guides were varied and their effects were investigated. With guides of long length, the fluctuation was not observed, and of medium length, the fluctuation was observed only in case of large diameter. However, when the length of the guides were short, the fluctuation took place just like in case of no guides. In this case, the existance of upward flow in the guide just before fluctuation occurred, resulted in reverse flow of the thermosyphon, however the Nusselt number showed same characteristics when the temperature of the orifice inlet was taken as the thermosyphon outlet temperature instead of as inlet temperature.

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

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.

Goretex를 이용한 융비술

최진영,민철기,명훈,황순정,서병무,이종호,정필순,김명진 大韓顎顔面成形再建外科學會 2003 Maxillofacial Plastic Reconstructive Surgery Vol.25 No.4

융비술시 실리콘 고무는 다루기 쉽고 조직 반응이 적어 현대 많이 돌출의 합병증이 생길 수 있다. 저자등은 이러한 실리콘의 단점을 보완할 수 있는 goretex를 사용하여 융비술을 시행하고 비첨에 대해서 자가연골을 이식하여 만족할 만한 결과를 얻었기에 goretex가 안면부 연조직의 증강을 위한 이식재료로 적합하다고 생각되어 문헌고찰과 함께 보고하는 바이다. Many different materials have been used to provide augmentation of the nasal dorsum. this include both autogenous and homogenous materials,as well as allografts. Silicone among the artificial materials has been most widely used. The silicone has some advantages and disadvantages. Goretex(expanded polytetra-fluoroethylene) which has widely used in vascular surgery and abdominal surgery can be used for facial soft tissue augmentation. The author presemts 2 cases of nasal augmentaion using goretex with literature review.

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).

프레탈^(R)정(실로스타졸 50mg)에 대한 실로졸^(R)정의 생물학적 동등성

최한곤,권기철,이승호,김학미,박병주,유봉규,이종달,이경희,하정희,우종수,박인숙,최진석,용철순 한국병원약사회 2003 병원약사회지 Vol.20 No.1

Bioequivalence of two cilostazol tablets, the Pletaal^(R)(Korea Otsuka Pharmaceutical Co., Ltd.) and the Cilozol^(R)(Hanmi Pharmaceutical Co., Ltd.), was evaluated according to the guideline of KFDA, Sixteen normal male volunteers(age 20~29 years old) were divided into two groups and a randomized 22 cross-over study was employed. After two tablets containing 50㎎ of cilostazol were orally administered. blood was taken at predetermined time intervals and the concentration of cilostazol in plasma was determined with an HPLC method using UV detector. The pharmacokinetic parameters(C_(max), T_(max) and AUC_(t)) were calculated and ANOVA was utilized for the statistical analysis of parameters. The results showed that the differences in C_(max), T_(max) and AUC_(t) between two tablets were 4.99%, 1.74% and 7.68%, respectively. The powers(1-β) for C_(max), T_(max) and AUC_(t) were83.92%, 80.12% and 85.03%, respectively. Detectable differences(Δ) and confidence intervals were all less than 20%, and confidence interval of all the parameters were also less than 20% at the significance level(α) of 0.05. All of these parameters met the criteria of KFDA for bioequivalence, indicating that Cilozol^(R) tablet is bioequivalent to Pletaal^(R) tablet.

전유전체 서열 분석과 가시화를 위한 워크벤치 개발과 응용

최정현,진희정,김철민,장철훈,조환규 한국유전학회 2002 Genes & Genomics Vol.24 No.2

An increasing number of genome sequencing projects results in explosive growth of whole genome sequences. Furthermore the number of studies on the functions of individual genes has also been rapidly increased. However on-memory algorithms are not applicable to the analysis of whole genome sequences, since the size of individual whole gene a ranges from several million base pairs to hundreds billion base pairs. In order to effectively manipulate the huge sequence data, it is necessary to use the indexed data structure for external memory. In this paper, we introduce the development and application of the workbench for the analysis and visualization of whole genome sequences using string B-tree that is suitable for the analysis of huge data. This system consists of two main parts, the analysis query part and the visualization part. The query system supports various transactions such as pattern matching, k-occurrence, and k-mer analysis. The visualization system helps biologists to easily understand whole genome structure and specificity by various kinds of visualization such as whole genome sequence viewer, annotation viewer, CGR (Chaos Game Representation) viewer, k-mer viewer, RWP (Random Walk Plot) viewer, and map viewer. We can find the relationships among organisms, support gene prediction in a genome, and study the function of junk DNA using our workbench. In this paper, we apply our workbench to investigating specific sequence such as avoided sequence, common sequence, and classifiable sequence.

Ciprofloxacin 제제의 생물학적 동등성에 관한 연구

최철희,신재국,신완균,유호진,이경훈,정원석,장인진,신상구 대한화학요법학회 1991 대한화학요법학회지 Vol.9 No.1

국내 시판중인 ciprofloxacin 제제인 Citopcin®(250㎎ tablet)의 동등성을 검토하기 위해 제조원인 Bayer사의 Citopcin®(250㎎ tablet)를 기준제제로 하여 18명의 건강한 남성 피험자를 대상으로 500㎎ 1회 교차 경구 투여후 약동학적 성상을 분석비교한 결과는 다음과 같다. 시험제제의 생체 이용율의 지표인 AUC, C_(mao), T_(max) 및 MRT들의 평균치는 백분율차이에 있어 모든 기준제제 지표의 ± 20% 이내였으며, 이들 생체 이용율 지표들은 분산분석 검정에서 차이를 인지할 수 없었다.생체 이용율 지표들의 기준제제에 대한 백분율 90% 대칭 신뢰구간 검토시 모든 경수들에서 ± 20% 이내의 조건을 만족하였으며 AUC의 경우에는 대칭형 신뢰구간으로 변환시 95% 신뢰구간에서도 동등성의 조건을 만족하였다, 이상의 시험결과로 시험제제인 Citopcin®은 기준제제인 Ciprobay®와 생물학적 동등한 제제로 판단되었다. The pharmacokinetics of ciprofloxacin was studied for the evaluation of the bioequivalence of the generic ciproflocacin products. Two single doses of 500㎎ each of ciprofloxacin(Ciprobay® 250㎎ tablet as a reference compound and Citopcin® 250㎎ tablet s a test compound) were administered orally to ighteen male volunteers in a balanced, randomized crossover design. Pek plasma levels of ciprofloxacin were observed about 1 hour after the doses and the peak concentrations of both products were similar(Ciprobay®, 3.18㎍/㎖; Citopcin®, 2.89㎍/㎖). The values of other pharmacokinetic parameter of ciprofloxacin computed for Ciprobay® are presented in that order: AUC=13.53:12.47㎍·h/㎖, T_(max)=1.28:1.14 hours; MRT=5.30:5.08 hours; t_(1/2)β=3.65:3.47 hours. No satistically significant, differences were detected when AUC and the other parameters were compared with the method of ANOVA. Using the criteria of 90% confidence interval for the assessment of bioequivalence al the parameters were acceptable. The products were found to be equivalent on the premise that no significant difference was detected when the relevant pharmacokinetic parameters were compared, and the confidence limit analysis showed acceptable results.