• 대한두경부종양학회지
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• 제35권2호
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• pp.35-38
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• 2019

Oncocytic lipoadenoma is a rare salivary gland tumor composed of adipose tissue and oncocytic epithelial cells in varied proportions. We report a case of an oncocytic lipoadenoma of the submandibular gland, which presented as a submandibular gland mass. The patient was a 65-year-old woman with a right submandibular mass measuring 2 × 2 × 1.6 cm. As a sonographic evaluation and computed tomograph scan gave us the impression of benign submandibular gland tumor such as pleomorphic adenoma, we resected the right side submandibular gland. Grossly, the tumor was well circumscribed with yellow to brown cut surface. Microscopically, the tumor was surrounded by a thin, fibrous capsule and composed of oncocytic epithelial cells admixed with mature adipose tissue. Final diagnosis was an oncocytic lipoadenoma. We discussed here radiologic and pathologic finding of this rare salivary gland tumor.

• 한국세라믹학회지
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• 제32권11호
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• pp.1269-1275
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• 1995

Effects of GeO2 addition on the thermal and structural stabilities of PbO-Bi2O3-Ga2O3 glasses were studied. Thermal stabilities, as assessed by the weighted thermal stability factors [(Tx-Tg)/Tg], increased with GeO2 concentraton from 0.097 to 0.210 with the addition of 20 mol% GeO2. Increasing GeO2 content resulted in the decrease of apparent density, molar volume, refractive index and thermal expansion. On the other hand, IR transmission cut-off (λT=50%) moved from 6.73${\mu}{\textrm}{m}$ for the ternary PbO-Bi2O3-Ga2O3 glass to shorter wavelength side, 5.98${\mu}{\textrm}{m}$ for a glass containing 20mol% GeO2. There were little change with GeO2 content, however, in the activation energies for the viscous flow of approximately 140 kcal/mole within the temperature interval of 300~50$0^{\circ}C$. Addition of GeO2 to PbO-Bi2O3-Ga2O3 glasses enhanced the thermal and structural stabilities significantly at the expense of their infrared transmittance. An appropriate compsomise between these two opposite trends should be made following the specifications of the final applications.

• 한국광학회지
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• 제16권6호
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• pp.494-499
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• 2005

코어가 확산된 단일모드 광섬유와 외부 물질 사이의 분산 특성의 차이를 이용하여 차단 특성이 우수한 단파장 통과 필터(short-pass filter)를 구현하였다. 두 물질의 결합 방법으로 측면 연마 기법을 도입하였다. 실험 결과 소자의 대역경계 파장(band edge wavelength)은 코어의 확산 정도로 조절이 가능하였다. 일반 통신용 단일 모드 대신에 열확산 코어 확산 광섬유를 도입함으로써 더 예리한 파장응답을 얻을 수 있었다. 열광학 효과를 이용하여 경계 파장을 400nm 이상 가변 할 수 있음을 관측하였다.

• 한국자기학회지
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• 제19권4호
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• pp.152-155
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• 2009

Ba-ferrite 단결정을 제조하여 자기적 성질을 $M\"{o}ssbauer$ 분광법으로 연구하였다. 단결정 시료를 c-축 방향으로 얇게 절단하고 그 면에 감마선을 조사한 결과 Fe 이온의 스핀방향이 c-축과 일치하였고 시료 전체에 걸쳐 단일 결정체임을 확인하였다. 특히 감마선이 스핀과 나란한 경우 $M\"{o}ssbauer$ 흡수선 중에서 결정 내에 존재하는 Fe의 5개 자리 중에서 단지 4개 자리에서만 공명흡수선이 존재하였고 2b 자리에서는 전혀 공명흡수가 일어나지 않았다. 2b 자리에서의 공명흡수가 일어나지 않는 이유는 대칭성이 있는 2개의 우물 형 위치에너지의 중심 사이를 Fe 이온이 매우 빠른 속도로 c-축을 따라 진동하는 것으로 설명할 수 있다.

• 한국전자파학회논문지
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• 제15권4호
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• pp.379-386
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• 2004

OFDM(orthogonal frequency division multiplexing) 통신 방식은 무선 고속 데이터 전송에 적합한 방식이다. 하지만 높은 PAPR(peak-to-average power ratio)의 발생으로 HPA(high power amplifier)에서 비선형 왜곡된다. 따라서 본 논문에서는 이 문제점을 개선시키기 위한 PAPR 저감 방법으로 dummy sequence를 삽입하는 새로운 방식의 SLM 기법(dummy sequence insertion - selected mapping: DSI-SLM)을 제안한다. 이 DSI-SLM 기법은 각각의 브렌치에 서로 다른 위상 factor를 곱하는 대신 각각에 일정비율의 부반송파에 dummy 시퀀스를 삽입하여 IFFT 후 가장 낮은 PAPR을 갖는 브렌치의 데이터를 전송한다. 이 방식들에 사용된 dummy 시퀀스는 송신단의 PAPR 저감만을 위해 사용하며 위상 회전 부가 정보 전송 및 복원 과정이 필요치 않아 기존 SLM에 비해 계산량 및 복잡도를 감소시킬 수 있다. 또한 PTS 방식에서 최적의 rotation factor를 찾기 위한 peak value optimization에 의한 계산량 증가 및 송신기의 시간 지연 문제 등을 해결할 수 있다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제28권6호
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• pp.464-471
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• 2002

The purpose of this study was to evaluate the stress patterns within fractured mandibles generated by reduction forceps and to determine the optimal position of the reduction forcep. Twenty-seven mandibular models were fabricated using a photoelastic resin. Each of the three sets of mandible models prepared was osteotomized according to one of three different fracture types(symphysis, parasymphysis and body fractures). After reducing the cut segments, a reduction forcep was placed into different engagement holes to compress the segments. Photoelastic stress analysis was used to visualize the stress patterns within the fractured mandiblular models generated by the reduction forcep. In the case of symphysis or parasymphysis fractures, an optimum distribution of stress over the fracture site was achieved when placing the reduction forcep more than 12.5mm on either side of the fracture line between the midway level bisecting the mandible and 5mm below the level. In the case of body fractures, optimum stress distribution was achieved when the reduction forcep was placed more than 15mm from the fracture line on the midway level. In conclusion, a correct use of reduction forceps helps to provide a precise threedimensional reduction for mandibular fractures.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제41권1호
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• pp.30-36
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• 2015

Objectives: The aim of this study is to determine the incidence, location, and orientation of maxillary sinus septa in formalin embalmed cadavers. Materials and Methods: The study was conducted on 210 cadaveric heads available in our department. After taking the mid-sagittal section the specimens were opened from the medial aspect and the sinus sinus septa, their anatomical plane, location and dimensions. Results: The mean linear distance between maxillary sinus floor and its anatomical ostium was $26.76{\pm}5.21mm$ and $26.91{\pm}4.96mm$ on right and left side, respectively. A total of 59 maxillary sinus septa (28.1%) were observed in 210 maxillary specimens. Septae were most common, 33 septa (55.9%), in the middle region (between first and second molar tooth) of the sinus cavity. The maxillary sinus membrane (Schneiderian membrane) adhered tightly to the maxillary sinus and over the septae. Significantly more maxillary sinus septa were observed in edentulous maxillae in comparison to the dentate upper jaw. Conclusion: Knowledge of location of maxillary sinus ostium is mandatory for the rhinologist for drainage of secretions in maxillary sinusitis. The morphological details of maxillary sinus septa, particularly their location and anatomical planes, will guide dentists in performance of safe implant surgeries. The maxillary antrum septa of category I and II may complicate the procedure of inversion of bone plate and elevation of sinus membrane during maxillary augmentation surgeries. The category III septa observed in the sagittal plane were embedded by one of the branches of the infraorbital nerve in it, and if accidentally cut will lead to infraorbital nerve palsy in maxillary sinus surgeries.

• 한국통신학회논문지
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• 제30권4A호
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• pp.288-295
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• 2005

OFDM(orthogonal frequency division multiplexing) 통신 시스템은 고속 무선 데이터 전송에 적합한 방식으로 널리 알려져 있지만, 높은 PAPR(peak-to-average power ratio)로 인하여 HPA(high power amplifier)에서 큰 비선형 왜곡을 겪는 문제점을 갖는다. 본 논문에서는 이러한 높은 PAPR을 저감하는 방법으로 더미 시퀀스(dummy sequence)를 삽입하는 새로운 SLM (selective mapping)방식을 제안하며, 이를 DSI-SLM기법이라 하기로 한다. 제안된DSI-SLM 기법은 각 브랜치(branch)에서 일정비율의 부반송파에 각기 다른 더미 시퀀스를 인가하고 IFFT(inverse Fourier transform) 후 가장 낮은 PAPR을 갖는 브랜치의 데이터를 전송한다. 이 방식에 사용된 더미 시퀀스는 송신단에서 PAPR 저감만을 위해 사용될 뿐 수신단에서의 데이터 복원 과정에는 필요로 하지 않으므로, 기존의 SLM및 PTS에서 나타나는 부가정보 전송의 필수성과 같은 단점을 해결하면서 실시간 데이터 처리를 가능케 한다.

• Journal of Community Nutrition
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• 제2권2호
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• pp.97-104
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• 2000

The purpose of this study was to investigate meal behavior and food preferences of children with different body types. This survey was conducted using a questionnaire for 274 boys and 257 girls in the 6th grade of elementary school in Anyang city. A questionnaire method was used. Food preferences of 14 food groups were tested with 5 likert scale points. Body types were divided with weight-length index(WLI) calculated by height and weight. The cut-off point for the underweight children was 90, and that of the overweight children was 100. The mean weight of the underweight children(26.2%) was 31.9$\pm$4.0kg, and that of the overweight children(26.9%) was 49.4$\pm$6.3kg. The average BMI of overweight children and underweight children was 21.0kg/$m^2$ and 15.5kg/$m^2$respectively. Perceived health status was different based on body types, and more of the overweight children answered they are healthy compared to the underweight children, Body types were not significantly different based on parent's education and occupation. Only 56.7% of the children ate breakfast at a regular time, 60% and 42.9% of the children had their lunch and dinner at regular time, respectively. Higher percentage of overweight children had irregular breakfast(20.1%) and skipped their breakfast and dinner compared to the other groups, however only dinner was statistically significant. The most frequently answered reasons for skipping meals were 'no time to eat'(50%) and 'bad side-dishes'(17.0%). Food preference was not different among the body type groups, however rice-cake was preferred in the underweight group, as well as milk and lettuce were preferred in overweight group. The preferences for milk and grain powdered drink(misitgaru) were same as or a carbonated soft drink. Focusing pubericant, it is necessary to have a regular breakfast. With regard to the importance of nutrition and health for children, the nutrition education for meal behavior and food preference to achieve a balanced diet should be considered.

• 디지털콘텐츠학회 논문지
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• 제16권5호
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• pp.717-725
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• 2015

전립선 영상은 비용이 상대적으로 저렴한 경직장 초음파 영상을 이용하여 전립선 진단에 많이 사용된다. 경직장 초음파 영상은 3차원으로 촬영되어 여러 장으로 하나의 진단 단위가 만들어 진다. 의사는 진단을 위해 2차원 영상을 순서대로 모니터에 표시하여 볼 수도 있고, 3차원의 영상을 볼 수도 있다. 2차원 영상은 원 영상을 그대로 출력하면 되지만, 3차원 영상은 다양한 각도에서 보이기도 하고, 내부의 어떤 면을 자른 형태로도 보여야 하므로 정확하게 전립선과 배경을 구분하여야 한다. 특히 경계를 구분할 때, 전립선의 중간 부분은 상대적으로 구분하기 쉬우나, 기저부와 첨단부는 불확실한 부분이 많으므로 경계를 구분하기기 매우 어렵다. 이에, 본 논문은 평균 형상 모델을 적용하여 전립선 경계를 추출하는 방법을 제안하고, 실험을 통하여 기존의 방법에 비해 우수함을 보인다.