Fountain Effect의 이해를 위한 실험 장치의 개발 및 적용

서은미,정기주,이춘우 공주대학교 사범대학 과학교육연구소 2000 과학교육연구 Vol.31 No.1

아래 부분이 물에 잠겨 회전하는 물체에 나타나는 fountain effect를 이론적으로 분석하고 실험 장치를 만들어 이를 확인하였다. We analyzed theoretically about the fountain effect which a rotating metal-sphere shows on water and comparing to the experimental results.

응급실 내원 환자의 만족도 평가 및 관련 요인에 대한 연구

서강석,감신,박정배,이정헌,김종근,윤영국,곽경숙,이원기,우석정 大韓應急醫學會 1998 대한응급의학회지 Vol.9 No.4

Background: To examine the influencing factors on patients' satisfaction in the emergency department(ED) for quality assurance. Methods: Patients who visited to the ED were prospectively investigated from November 1 to December 31, 1997. Authors developed questionnaire to investigate influencing factors on patients' satisfaction. A Chi-square test and LISREL 7.0 were applied for statistical analysis. Results: Patients' satisfaction was significantly related to physical environment variables, accessibility variables, kindness of hospital personnel variables, and patient's trust for doctors variables. In path analysis, willingness for revisit was influenced by patients' satisfation, accessibility, physical environment, patients' trust for doctors in order, and willingness for recommendation was influenced by accessibility, patients' satisfaction, and kindness of hospital personnel in order. Conclusions: The influencing factors on patients' satisfaction are physical environment, accessibility, kindness of hospital personnel, and patient's trust for doctors. Willingness for revisit and willingness for recommendation are influenced by patients' satisfation. In spite of some limitations, the results of this study can be used as a baseline information for exploring the influencing factors on patients' satisfaction. Further comprehensive research efforts should be made on the study of patients' satisfactoin in the ED.

3차원 전산화단층촬영 영상을 이용한 안면 연조직 두께 계측의 임상적 유용성

정호걸,김기덕,한승호,허경석,이제범,박혁,최성호,김종관,박창서 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.36 No.2

Purpose : To evaluate clinical usefulness of facial soft tissue thickness measurement using 3D computed tomographic images. Materials and Methods : One cadaver that had sound facial soft tissues was chosen for the study. The cadaver was scanned with a Helical CT under following scanning protocols about slice thickness and table speed; 3 mm and 3 mm/sec, 5 mm and 5 mm/sec, 7 mm and 7 mm/sec. The acquired data were reconstructed 1.5, 2.5, 3.5 mm reconstruction interval respectively and the images were transferred to a personal computer. Using a program developed to measure facial soft tissue thickness in 3D image, the facial soft tissue thickness was measured. After the ten-time repeation of the measurement for ten times, repeated measure analysis of variance (ANOVA) was adopted to compare and analyze the measurements using the three scanning protocols. Comparison according to the areas was analyzed by Mann-Whitney test. Results : There were no statistically significant intraobserver differences in the measurements of the facial soft tissue thickness using the three scanning protocols (p>0.05). There were no statistically significant differences between measurements in the 3 mm slice thickness and those in the 5 mm, 7 mm slice thickness (p>0.05). There were statistical differences in the 14 of the total 30 measured points in the 5 mm slice thickness and 22 in the 7mm slice thickness. Conclusion : The facial soft tissue thickness measurement using 3D images of 7 mm slice thickness is acceptable clinically, but those of 5 mm slice thickness is recommended for the more accurate measurement.

小兒의 Virus性 肝炎

徐廷期 대한가정의학회 1984 Korean Journal of Family Medicine Vol.5 No.7

백서 대뇌피질절편에서 산소 및 포도당 결핍에 의한 [³H]Acetylcholine의 유리에 관한 연구

이정주,김기원,서만욱,김영현,김기원 대한신경과학회 1998 대한신경과학회지 Vol.16 No.4

치성각화낭과 법랑모세포종의 임상 및 방사선학적 감별진단

정호걸,이장렬,김기덕,박창서 大韓口腔顎顔面 放射線學會 2000 Imaging Science in Dentistry Vol.30 No.4

Purpose : To clarify the clinical and radiologic parameters that can be used to differentiate odontogenic keratocyst and ameloblastoma Materials and Methods : The records of 46 patients of ameloblastoma and 48 patients of odontogenic keratocyst at the Yonsei University Dental Hospital during the period of 1979 to 1995 were retrospectively reviewed. As a possible means for differentiating between the odontogenic keratocyst and ameloblastoma, the clinical parameters and the radiologic parameters were evaluated. Results : In the clinical parameters, there was no significant difference in age, sex, and sign and symptoms (p 〉 0.05). In the radiologic parameters, there was significant difference in site, shape of the lesion, and external root resorption of adjacent teeth (p 〈 0.05). Conclusion : The site, shape of the lesion, and external root resorption of adjacent teeth can be the parameters to differentiate odontogenic keratocyst and ameloblastoma, but a definite differentiation of these two lesions needs a more specialized imaging modality. (Korean J Oral Maxillofac Radiol 2000;30:249-254)

두개골의 3차원 영상 분석을 위한 전산화단층촬영 방법의 비교 : 상층 두께가 3차원 영상의 계측에 미치는 영향

정호걸,김기덕,박혁,김동욱,정해조,김희중,유선국,김용욱,박창서 대한구강악안면방사선학회 2004 Imaging Science in Dentistry Vol.34 No.3

Purpose : To evaluate the quantitative accuracy of three-dimensional (3D) images by means of comparing distance measurements on the 3D images with direct measurements of dry human skull according to slice thickness and scanning modes. Materials and Mathods : An observer directly measured the distance of 21 line items between 12 orthodontic landmarks on the skull surface using a digital vernier caliper and each was repeated five times. The dry human skull was scanned with a Helical CT with various slice thickness (3, 5, 7 mm) and acquisition modes (Conventional and Helical). The same observer measured corresponding distance of the same items on reconstructed 3D images with the internal program of V-works 4.0 (Cybermed Inc., Seoul, Korea). The quantitative accuracy of distance measurements were statistically evaluated with Wilcoxons’ two-sample test. Results : 11 line items in Conventional 3 mm, 8 in Helical 3mm, 11 in Conventional 5 mm, 10 in Helical 5 mm, 5 in Conventional 7 mm and 9 in Helical 7 mm showed no statistically significant difference. Average difference between direct measurements and measurements on 3D CT images was within 2 mm in 19 line items of Conventional 3 mm, 20 of Helical 3 mm, 15 of Conventional 5 mm, 18 of Helical 5 mm, 11 of Conventional 7mm and 16 of Helical 7 mm. Conclusion : Considering image quality and patient’s exposure time, scanning protocol of Helical 5 mm is recommended for 3D image analysis of the skull in CT.

상악 치아군의 저항중심의 위치에 관한 3차원 유한요소 해석

정광모,성상진,이기준,전윤식,모성서 대한치과교정학회 2009 대한치과교정학회지 Vol.39 No.2

최근 골내 고정 형태의 temporary anchorage device (TAD)를 많이 이용하게 되면서 다양한 위치로부터 그리고 강한 교정력을 이용할 수 있게 되었다. 이에 따라 치아군의 이동양상을 예측하고 치료계획을 세우기 위하여 다양한 치아군의 저항중심의 위치에 대한 이해가 필요하게 되었다. 본 연구에서는 3차원 유한요소해석을 이용하여 상악 4전치, 6전치 그리고 상악 전치열에서 3차원적 저항중심의 위치를 조사하고자 하였다. 이를 위하여 상악 전치열 14개 치아와 치근막 및 치조골의 3차원 유한요소모델을 제작하였고, 각 치아군별로 치관부를 협측, 설측 호선, 설측 splint wire로 고정하여 개별 치아이동을 최소화하고 적용된 힘이 치아에 고루 분산되도록 하였다. 상악 중절치 절단연의 중점에서 연장된 와이어 빔에 수직, 수평으로 100 g 또는 200 g의 힘을 가하여 치아의 변위를 해석하고, 각 치아군에 속한 치아들이 최대한 평행이동 되는 힘의 적용부위를 저항중심으로 정의하였다. 연구결과 상악 4전치군의 저항중심은 상악 중절치 절단연으로부터 치근방향 13.5 mm, 후방 12.0 mm, 상악 6전치군은 상악 중절치 절단연으로부터 치근방향 13.5 mm, 후방 14.0 mm에 위치하였으며 상악 전치열군의 저항중심은 상악 중절치 절단연으로부터 치근방향 11.0 mm, 후방 26.5 mm에 위치하였다. 본 유한요소 실험모델을 이용하여 얻은 결과는 교정치료의 효율성을 높일 수 있으리라 생각된다. Objective: The aim of this study was to investigate the 3-dimensional position of the center of resistance of the 4 maxillary anterior teeth, 6 maxillary anterior teeth, and the full maxillary dentition using 3-dimensional finite element analysis. Methods: Finite element models included the whole upper dentition, periodontal ligament, and alveolar bone. The crowns of the teeth in each group were fixed with buccal and lingual arch wires and lingual splint wires to minimize individual tooth movement and to evenly disperse the forces to the teeth. A force of 100 g or 200 g was applied to the wire beam extended from the incisal edge of the upper central incisor, and displacement of teeth was evaluated. The center of resistance was defined as the point where the applied force induced parallel movement. Results: The results of study showed that the center of resistance of the 4 maxillary anterior teeth group, the 6 maxillary anterior teeth group, and the full maxillary dentition group were at 13.5 mm apical and 12.0 mm posterior, 13.5 mm apical and 14.0 mm posterior, and 11.0 mm apical and 26.5 mm posterior to the incisal edge of the upper central incisor, respectively. Conclusions: It is thought that the results from this finite element models will improve the efficiency of orthodontic treatment.

3차원 전산화단층촬영 영상을 이용한 얼굴 연조직 두께 계측

정호걸,김기덕,한승호,신동원,허경석,이제범,박혁,박창서 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.37 No.1

Purpose : To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. Materials and Methods : One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side, The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. Results : There were no statistically significant differences between the direct measurements and those using the 3D images (p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. Conclusion : The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissues thickness more easily in forensic science and anthropology. (Korean J Oral Maxillofac Radiol 2006; 36 : 49-54)

나이에 따른 한국인 정상 이하선의 전산화단층촬영값의 차이

박창서,김기덕,이은숙,정호걸 大韓口腔顎顔面 放射線學會 1999 Imaging Science in Dentistry Vol.29 No.2

Purpose : To determine normal CT number range of parotid gland by analyzing the change by age increase and the difference among individuals and between both sexes in CT number of normal parotid gland. Materials & Methods : 134 subjects who took the CT scan between the period of Jan. 1996 and Dec. 1997 at Yonsei University, Dental Hospital were selected. Criteria for selection were that the patients must be within the normal range clinically and radiologically, and the entire parotid gland on the axial view must be shown. Among the axial views, the one showing the greatest parotid gland size was selected and its CT number was recorded. Also, CT numbers from both masseter muscle were recorded as its control. Results : There was statistically significant correlation between CT number of right and left of parotid glands and masseter muscles. With the increase of age, there is a significant decrease in the CT number of parotid gland(p<0.05). There was no statistically significant difference in CT number between sexes except the 7th decade and beyond age group of parotid gland(p>0.05). Conclusion : As age increases, CT number of parotid gland has a tendency to decrease, and there is no significant difference in the CT numbers between left and right parotid gland. Therefore in the CT scan of patients suspected of having a salivary gland disease of the parotid gland, to consider normal range of the age-dependent CT numbers of parotid gland and compare the CT numbers of the right and left parotid gland might be useful in diagnosing the disease.(J Korean Oral Maxillofac Radiol 1999;29:451-458)