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The prediction of the tooth size in the mixed dentition for Korean
Moon, Sung-Hwan,Kim, Seong-Oh,Yu, Hyung-Seong,Choi, Byung-Jai,Choi, Hyung-Jun,Lee, Jae-Ho 大韓小兒齒科學會 2006 大韓小兒齒科學會誌 Vol.33 No.2
이번 연구의 목적은 혼합치열기 아동에서 미맹출된 견치와 소구치의 크기를 예측하는데 있어서 한국인에 맞는 방정식을 만들기 위함이다. 미맹출 치아의 크기를 예측하는 것은 혼합치열기 교정 진단과 치료계획 수립에 있어서 매우 중요하다. 미맹출된 견치와 소구치 크기를 예측하는 방법은 몇가지가 있지만 그중에서도 가장 흔하게 쓰이는 것이 모이어의 예측표와 다나카와 존스턴의 방정식이 있다. 하지만 그것들은 백인을 위해서 제작된 것이고 치아 크기는 인종에 따라서 다르다고 알려져 있다. 이번 연구에서는 치아크기를 측정하여 하악 영구 절치의 크기 합과 견치 및 소구치의 크기 합 사이의 상관관계를 구하고 회귀방정식을 이용해서 한국인에 맞는 예측표를 만들었다. 연세대학교 치과대학에 재학중인 178명의 한국 학생(남 108명, 여 70명, 평균연령 21.63)을 대상으로 실험하였다. 영구치의 근원심 폭경을 석고모형상에서 calipers를 이용해서 측정하였다. 성별간의 치아 크기는 차이가 있었다(p<0.05). Correlation coefficient는 0.57에서 0.64의 범위였고, standard errors of the estimates 는 여성에서 0.6으로써 남성보다 우수하였다. r^(2)값은 0.27에서 0.41의 범위를 나타내었다. Estimating the size of unerupted teeth is an essential aspect of orthodontic diagnosis and treatment planning in the mixed dentition. Several methods were introduced and used for the prediction. The most common methods among these would be Moyers probability chart and Tanaka and Johnston equations. These are currently used widely, but they were developed for Caucasians. Because there are clear racial differences in teeth size, the objectives of this study were to produce correlation coefficients between the combined mesiodistal widths of the permanent mandibular incisors and those of the canines and premolars for each quadrant, and prediction tables with regression equations, specifically for Korean. 178 young adults (70 women, 108 men, mean age 21.63 years) were selected from the College of Dentistry, Yonsei University, Seoul, Korea. The mesiodistal crown diameters of the permanent teeth were measured with calipers. Significant sexual dimorphism was found in tooth sizes. The correlation coefficients between the total mesiodistal width of the mandibular permanent incisors and those of the maxillary and mandibular canines and premolars were found to be between 0.52 and 0.64. The standard error of the estimatation was better (0.60) for women and the r^(2) values ranged from 0.27 to 0.41 for both sexes, Prediction tables were prepared for Korean. This study showed larger canine and premolar diameters than Tanaka and Johnston's and Moyers' studies which might be due to the racial differences. Further investigations with a larger sample size will be needed for more representative data on the Korean population.
김주환,장무성,김상부 國立 昌原大學校 產業技術硏究院 2004 産技硏論文集 Vol.18 No.-
Since 1996, many Korean companies such as Samsung, LG, Hyundai Motor Company, have adopted Six Sigma in order to get a competitive edge in the global marketplace. There are, however, many problems to be solved for successfully implementing Six Sigma in an organization. As is known, one of the key principles of Six Sigma is a data-based management or a decision making based on data. Therefore, Six Sigma requires more measurement than ever, which makes measurement system analysis more important. Usually, a gage R&R study is performed to identify the measurement system's variation relative to process variation. In the study, a gage R&R study is considered for the case where measuring a major quality characteristic accompanies a destructive testing. We suggest a gage R&R study using a screening variable that is highly correlated with the major quality characteristic and also can be measured by a nondestructive testing method. It is assumed that the major quality characteristic and a screening variable have a bivariate normal distribution. A simulation study on the proposed method is performed and we compare it with the conventional gage R&R study for a destructive testing.
수용성 TMAH 암모니아계를 이용한 실리콘 이방성 식각
정귀상,송승환,박진성,최영규 동서대학교 부설 연구소 1996 연구소 논문집 Vol.1 No.-
Si anistropic etching is a key technology for micromachining. The main advantages of teramethyl ammonium hydroxide (TMAH)-based solution are their full compatibility with IC process. In this paper, the anisotropic etching characteristics of single crystal Si in a TMAH ((CH??)??NOH) based solution was described. The influence of the adition of IPA to TMAH solution on their etching characteristics was also presented. The etching rate ratio of Si (111)/(100) is increased with increasing TMAH concentration. The addition of IPA to TMAH solution leads to smoother furfaces of sidewalls etched planes and reduce undercutting ratio by a factor of 2-3. Finally, the p?? Si anisotropic etching characteristics by means of heavily boron doping was investigated.
박성근,송중원,한기환,강진성,박관규 大韓成形外科學會 1991 Archives of Plastic Surgery Vol.18 No.3
Onlay graft of the calvarial bone has been popularized in craniofacial surgery because absorption of the calvarial bone is less than that of the endochondral bone. But the problems with using the calvarial bone are its rigidity and difficulty in setting a precise apposition. When the outer tables of the calvarial bone are used for augmentation and reconstruction of the convex zygoma, forehead, or chin, it is better to place the cancellous surface over the convex recipient bone to get a precise apposition. Whereas, it is better to place the cortical surface over the concave nose or orbital cavity to achieve a good apposition. Therfore, our study was designed to determine the differences of bone absorption and regeneration between cancellous and cortial bone contact to facial bone, and between preserved periosteum and detached periosteum in autograft of calvarial bone in dog models. Outer tables of the calvarial bone were placed in subperiosteal pockets of the upper and lower maxilla in four different ways : Group I ; The cancellous surface was placed in contact with the bare recipient bone, and the cortical surface attached with periosteum was accordingly contacted with the elevated periosteum of the recipient bone. Group Ⅱ ; The corical surface attached with periosteum was placed in contact with the bare recipient bone and the cancellous surface was contacted with the elevated periosteum of the recipient bone, Group Ⅲ ; The arrangenent was similar to Group Ⅰ except that the periosteum of the graft was deprived. Group Ⅳ ; The arrangement was similar to Group Ⅱ except that the periosteum of the graft was deprived. Volume measurements using a caliper technique and histological study were made 20 weeks postoperatively. The volume of maintenance is as follows ; Group Ⅰ, 84.2% ; Group Ⅱ, 77.6% ; Group Ⅲ, 77.0%, and Group Ⅳ, 69.5%. The histolgical contribution of living bone was assessed by a modified point counting technique : Group Ⅰ, 86.6%, Group Ⅱ, 83.8% ; Group Ⅲ, 79.6% and Group Ⅳ, 77.6%. Greater volume maintenance and histological contribution of living bone were found when cancelllous surface rather that the cortical were placed in contact with the recipient bone and the grafts from their periosteum were preserved. We concluded that in order to expect better survival of a grafted bone, the cancellous surface of the graft should contact with the recipient bone and that the periosteum of the graft should be preserved.