• 대한치과교정학회지
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• 제26권6호
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• pp.657-666
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• 1996

Orthopantomogram is commonly used to evaluate root parallelism. "Good parallelism" between roots is widely accepted as one of the guidelines of a successful orthodontic treatment. In case there was a large angle between crown axis and root axis, and if we valued only the position of crown in establishing occlusal relationship without considering of the situation of root, the problem of root arrangement between adjacent teeth would be occurred. The estimate of root parallelism in mesiodistal direction before and after orthodontic treatment must be emphasized. The intent of this study was to determine the clinical importance and correlation of the angle between crown axis and root axis. Orthopantomograms of 105 orthodontic patients being treated in Yonsei university were used in this study. Twenty-eight teeth in both maxilla and mandible were selected and analyzed quantitively to evaluate the angle between crown axis and root axis, and obtain the correlationship among the individual teeth. The results are as follows: 1. Among the teeth presenting normal distribution, the maxillary right canine showed the largest mean value( $5.73{\pm}4.42^{\circ}$), which was composed of the crown-root angles, and the mandibular left lateral incisor showed the smallest mean value( $0.60{\pm}3.76^{\circ}$). 2. The crown-root angles of the maxillary incisors and the first molars, and the mandibular central incisors and the first molars didn't show normal distribution and the ranges of these angles were dispersed. 3. Significant differences were present between the crown axis and the root axis except for lower first premolars. (p<0.05) 4. No significant difference was present for the crown-root angle between right and left side, (p<0.05) 5. No significant difference was present for the crown-root angle between male and female except for lower left first premolar. (p<0.05) 6. In the upper right quadrant, significant correlations were present between crown-root angles of the central incisor and lateral incisor, lateral incisor and canine. In the upper left quadrant, significant correlations were present between crown-root angles of the central incisor and lateral incisor. In the lower right quadrant, significant correlations were present between crown-root angles of the central incisor and lateral incisor, first molar and second molar. In the lower left quadrant, significant correlations were present between crown-root angles of the central incisor and lateral incisor, lateral incisor and canine, first molar and second molar. (p<0.05)

• 대한소아치과학회지
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• 제45권3호
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• pp.334-343
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• 2018

이번 연구에서는 상악 중절치의 편측성 맹출 장애의 원인을 조사하고 매복된 치아들의 매복깊이, 매복각도, 치근발육 상태를 치과용 Cone-beam CT로 분석하여 치료방향을 예측하는데 도움이 되고자 하였다. 총 134명의 환자 중 상악 중절치의 편측성 맹출 장애로 진단된 평균연령은 7.9세였으며, 남자가 여자보다 2.1배 더 높은 빈도를 나타냈다. 맹출 장애의 주원인은 물리적 장애물로 과잉치와 치아종이 대부분을 차지하였다. 편측성 맹출 장애를 보였던 치아 중 물리적 장애물을 제거한 후, 78증례는 자발적으로 맹출하였으며 56증례는 비자발적으로 맹출하였다. 또한 편측성 매복 상악 중절치의 자발적 혹은 비자발적 맹출은 매복깊이, 매복각도, 치근발육 정도와 연관성이 있었다. 정상적으로 맹출한 치아의 매복 각도는 $50^{\circ}-90^{\circ}$ 사이였으며, 매복 상악 중절치의 자발적 맹출 빈도도 이 범위에서 가장 높았다. 또한 자발적 맹출에 걸린 시간은 매복각도와 치근 발육보다 매복깊이와 높은 상관관계를 보였다. 비자발적 맹출을 보였던 치아들 중 대부분은 교정적 견인에 의해 구강내로 맹출 되었고, 그 기간은 약 12개월 정도 걸렸으며, 교정적 견인기간은 매복깊이, 매복각도, 치근발육 정도와 통계적인 유의성을 나타내지 않았다. 이번 연구의 결과들은 편측성 상악 중절치 맹출 장애의 원인과 치료에 대한 정보를 제공할 수 있었으며, 치료 결과를 제공함으로써 향후 치료계획을 세우는데 도움이 될 수 있으리라 생각된다.

• 한방비만학회지
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• 제1권1호
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• pp.1-11
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• 2001

Obesity is a metabolic disease associated with multiple hormonal abnormalities. Therefore, obesity management aims at balancing these endocrine malfunctions nowadays. Although many studies proved interactions of hormones related with obesity, there are still lots of controversies. Most of these malfunctions are more pronounced in central, visceral obesity than in peripheral obesity. Recently, it is revealed that a central lesion of endocrine malfunction in human visceral obesity is probably related with a hypersensitivity of hypothalamopituitary-adrenal(HPA) axis. Probably associated with this axis, Insulin and cortisol promote lipid accumulation by expressing lipoprotein lipase activity, while sex hormones and growth hormone exert the opposite effects. Also reviewed was thyroid hormone which is closely related with thermogenesis. Serotonin is prescribed as antidepressant and it is applied to some eating disorders. Recently, leptin made in fat deposit also took attentions in terms of regulator of appetite and messenger of sex signal.

• Computers and Concrete
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• 제29권3호
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• pp.127-144
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• 2022

To investigate the flexural stiffness of the steel-composite beam, the contributions of the concrete slab and steel beam to the stiffness were considered separately. The method for flexural stiffness of the composite beam, considering the stiffness of the concrete slab and steel beam, was proposed in this paper. In addition, finite element models of the composite beams were established and validated. Parametric analyses were carried out to study the effects of different parameters on the neutral axis distance reduction factors of the concrete slab and steel beam. Afterward, the neutral axis distance reduction factors were fitted, and the stiffness combination coefficients of the two parts were solved. Based on the stiffness combination coefficients, the flexural stiffness of the composite beam can be obtained. The proposed method was validated by the tested and analyzed results. The method has a simple form and high accuracy in predicting the flexural stiffness of the steel-concrete composite beam, even though the degree of shear connection is less than 0.5.

• Radiation Oncology Journal
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• 제9권1호
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• pp.159-164
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• 1991

전중추신경 방사선 조사는 수아세포종, 중추신경정상피종, 중추신경임파종, 중추신경백혈병 환자 치료에 시행한다. 뇌부위에는 양면 조사야를 통하고 척추 신경부위는 후면 단일 조사야를 통해 방사선 조사한다. 이때 조사야가 인접한 부위에서 발생하는 방사선조사야의 중첩에 의한 선량의 불균일성은 큰 문제로, 특히 척추신경의 극히 한정된 방사선 인내능력으로 인해 심각한 부작용을 병발할 수 있다. 이 문제를 해결하기위한 많은 연구가 보고되고 있으나 그들이 보고한 방법에 의해서도 불균일성은 최고 $60\%\sim70\%$로 부터 최소 $15\%\sim20\%$에 이른다. 저자는 split beam (central axis beam)과 collimator rotation technique을 이용하거나 collimator/couch rotation technique을 이용하여 3조사야가 접하는 부위의 방사선량의 불균일성을 해결하고자 시도하였다. 저자의 방법으로 시행할 때 3조사야가 접하는 부위에서의 불균일성은 $5\%$정도로 감소시킬 수 있었다. 본 논문에서 저자의 방법의 장단점을 기술하였다.

• 한국유체기계학회 논문집
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• 제16권4호
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• pp.22-27
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• 2013

The purpose of this paper is to perform the structural design of the small scale vertical-axis wind turbine (VAWT) blade using a response surface method(RSM). First, the four design factors that have a strong influence on the structural response of blade were selected. Analysis conditions were calculated by using the central composite design(CCD), which is a typical design of experiment for the response surface method(RSM). Also, the significance of the central composite design(CCD) was verified using analysis of variance(ANOVA). The finite element analysis was performed for the selected analytical conditions for the application of response surface method(RSM). Finally, a optimization problem was solved with a objective function of blade weight and a constraint of allowable stress to achieve a optimal structural design of blade.

• 핵의학기술
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• 제14권2호
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• pp.172-176
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• 2010

PET/CT 검사에서 발생하는 환자의 움직임은 감쇠보정의 불일치를 초래하여 정량평가에 영향을 주게 되어 결과의 정확도를 저하시키게 된다. 본 연구에서는 PET/CT 3D 영상촬영에서 투과촬영 후 방출촬영의 위치변화에 따른 감쇠보정 불일치 시 감쇠보정 위치 변화 방법을 이용한 영상재구성법의 유용성에 대하여 평가하였다. GE Discovery STE16 장비에 스티로폼($20{\times}20{\times}10$ cm)의 중심점을 기준으로 x, y축 방향으로 ${\pm}2$, 6, 10 cm까지 1 mL 주사기 삽입 공간을 제작하였다. $^{18}F$-FDG 5 kBq/mL의 주사기를 중심점에서 투과촬영한 후 위치를 변화하여 방출촬영하고 위치 변화에 따른 감쇠보정 방법을 사용하여 영상을 얻었다. 재구성 방법은 반복영상 재구성법으로 반복횟수 2회, 부분집합 수 20을 적용하였으며 모든 방출촬영 데이터는 시간경과에 따른 붕괴보정을 적용하였다. 또한 주사기 위치에 관심영역을 설정한 후 방사능 값(kBq/mL)과 중심점에 대한 각 위치에서의 백분율 오차를 비교하였다. 방출영상의 중심점의 방사능 값은 2.30 kBq/mL이며, +x축 1.95, 1.82, 1.75 kBq/mL, -x축 2.07, 1.75, 1.65 kBq/mL, +y축 2.07, 1.87, 1.90 kBq/mL, -y축 2.17, 1.85, 1.67 kBq/mL로 나타났고, 백분율 오차는 +x축 15, 20, 23%, -x축 9, 23, 28%, +y축 12, 21, 20%, -y축 8, 22, 29%로 산출 되었다. 그리고 방출 영상에서 감쇠보정 위치변화 방법을 사용 하였을 경우 +x축 2.00, 1.95, 1.80 kBq/mL, -x축 2.25, 2.15, 1.90 kBq/mL, +y축 2.07, 1.90, 1.90 kBq/mL, -y축 2.10, 2.02, 1.72 kBq/mL로 나타났으며, 백분율 오차는 +x축 13, 15, 21%, -x축 2, 6, 17%, +y축 9, 17, 17%, -y축 8, 12, 25%로 산출 되었다. 감쇠보정 불일치 시 감쇠보정 위치변화 방법을 사용한 경우의 방사능 농도 값은 x, y축에서 평균 0.14, 0.03 kBq/mL 증가 하였고, 백분율 오차는 6.1, 4.2% 향상되었다. 또한 중심으로부터 멀어질수록 공간분해능이 저하되는 특성상 중심에서 먼 위치일수록 방사능 값의 저하현상은 커짐을 알 수 있었다. 그러나 실제 임상에서는 감약 정도가 더 커지기 때문에 이러한 불일치 시 그 오차는 더 클 것으로 사료된다. 따라서 감쇠보정이 일치하지 않는 부분의 병변에서는 감쇠보정 위치변화 방법을 적용하여 방사능 값의 오차를 감소시킬수 있을 것이다.

• 한국실내디자인학회논문집
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• 제29호
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• pp.281-288
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• 2001

It shows 21st century as a networking society that is moving up the concept of global town and being industrialized with regional and personal connections. Individual's original idea and variety of 21th century may be respected by such environmental change, and age (Literary, human axis, technology axis, nature axis, kaining farming axis are central keyword) of culture that cultural capacity of individual becomes important fetters that create added value is forecasted to become. The moaning for space that is unemployment enemy by change of conceptional environment about cultural life and agreeable quality of life by development of Information-Communication technology may be required newly. As it does interaction along with development of science technique and Information-Communication technology, the future environment of various that complex! Is predicted to form network environment (existence space, cyberspace) newly. Human central interest is risen in technology balance hereupon, and these characteristic escaped in physical system that do with functional special quality and require human central and sensitive interaction. First, if examine about phenomenon by Digitize and chance aspect that is risen in 21th century, Digitize is time that action occurs fusion Tuesday that is various and Blur phenomenon of city·space, and the period to collapse the border between several individual. Second, importance more than man-centered and sensitive aspect of functional physical system is risen by digital age with development of technology medium, and as the five digital senses showed up, it suggests a sensual of the times and therefore the interest and direction get set up for the sensual sides of consumers. Third, special quality is, medium enemy by that digital space connotes meaning disk floret, variability, transparency, space red of extensity etc.. to burn and is digitalised, can be risen by symbolic, original individualities and emotional communication's the importance is required sensitivity enemy who is sympathy horn by fusion anger of individual. Technology of new media may open direction of new communication through interface that did not enjoy so far is going to supply new means that can express own to human

• Radiation Oncology Journal
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• 제13권2호
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• pp.199-203
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• 1995

Purpose: To evaluate the dose under lung block as a function of depth and the effectiveness of a block as a function of block width. Materials and Methods : Field size of mantle field was $22.8{\times}32.4cm^2.$ Dose distribution of the mantle field was measured with two dimensional water phantom system. To analyze the effectiveness of the lung block. central axis plane, 5cm off-axis plane, and 10cm off-axis plane were studied. Results: The dose under the lung block was recorded with maximum at the depth between 5cm and 10cm. In the central axis plane, dosimetric block width was $10-15\%$ less than physical block width. In the 5cm off-axis plane, dosimetric block width was $4-9\%$ less than physical block width. In the 10cm off-axis plane, dosimetric block width was $2\%$ less than physical block width. Conclusion: Depth dependence of the dose under the lung block was founded. Also, block width dependence of the lung block was founded. To induce the accurate relation between the physical block width and the 'effective' block width, it needs more detailed understanding of the variables involved.

• Clinics in Shoulder and Elbow
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• 제2권2호
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• pp.151-156
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• 1999

Purpose : Average humeral head retroversion was showed significant wide range from literatures based on variable measuring technique, We performed computed tomography(CT) study in an effort to define the specific anatomy relationships and evaluate their use. Materials and Methods : Two hundreds shoulders and distal humeri CT scan with no known pathology were examined. The study population was divided to 10 groups by gender and age (from third to seventh decade). The number of each group was twenty. Retroversion of proximal humerus and glenoid were measured using the lines that were connected the central axis of humeral head, central points of the humeral epicondyles paralleling to the trochlea, paralled to the glenoid surface, midpoint between the transverse glenoid diameter and medial edge of the scapular. We also measured the bicipital groove distance from the humeral central axis and scapulothoracic angle. Results: Retroversion of proximal humerus was highly variable, ranging in this study from 13 to 58 degrees(mean 28.73) These values correlated with sex, not age, height or hand dominance. Glenoid retroversion at the inferior sections showed average 1.3 degree, did not signigicant differences. The central axis was an average of l0mm(5-15mm) posterior to the posterior margin of the bicipital groove. Scapulothoracic angle was average 43 degrees(25-53 degrees) Conclusion: Anatomical reconstruction of retroversion angle should be individualized and bicipital groove could be useful as landmark for the lateral fin of the prosthesis to be positioned an average of 10mm posteriorly.