• 한국임상보건과학회지
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• 제1권1호
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• pp.29-34
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• 2013

Purpose : This study was to investigate that tongue positions have effect on the cervical range of motion (ROM). Methods : 18 subjects, 20 to 25 years of age, were participated in this study. The tongue positions were neutral position, anterior protrusion, posterior protrusion, superior protrusion, inferior protrusion, left side protrusion and right side protrusion. The neck movements were right side flexion, left side flexion, right rotation and left rotation. The cervical range of motion measured by cervical range of motion instrument (CROM, C9266-49, USA). The changes were analyzed using the paired t-test. SPSSWIN (ver. 20.0) was used for data analysis and the significance level was chosen as ${\alpha}$=0.05. Results : In the lateral flexion, the angle of left lateral flexion increased in anterior protrusion(p<0.05) and right side protrusion(p<0.05) significantly. In the rotation, the angle of right rotation increased in anterior protrusion(p<0.05), posterior protrusion (p<0.05), superior protrusion(p<0.05), inferior protrusion(p<0.05), and left side protrusion (p<0.05) significantly. Conclusions : In conclusion, we found that the tongue positions affected some cervical movements.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2352-2356
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• 2008

Heat transfer and performance characteristics have been investigated for a rectangular wavy duct with dimple or protrusion arrays. The test duct was 15mm in height and 105mm wide. The print diameter of the dimple/protrusion wall was 12.99mm and the depth/height of the dimple/protrusion was 3.75mm. Local heat transfer coefficients on the dimple/protrusion wall were measured using a transient TLC technique. The Reynolds number was varied from 3,000 to 10,000. For the wavy duct tested in this study, adverse static pressure characteristics occurred at turning region of the wavy duct due to secondary flows. For the wavy duct with protrusion array, higher heat transfer enhancement level of 7.4 times than smooth straight case in maximum was obtained at low Reynolds number due to the high heat transfer enhancement by vortex flows. Also, the protrusion array increased the performance level of 3.0 at low Reynolds number of 3,000.

• 설비공학논문집
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• 제10권1호
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• pp.129-136
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• 1998

Pressure drop and heat transfer characteristics of a periodically fully developed flow in the flat channel with protrusions are investigated. The effects of shape and location of protrusion on the pressure drop and heat transfer are numerically analyzed in the present study. Taguchi method is used to optimize these parameters. It is found that the ratio of the height of protrusion to channel height shows larger influence on the pressure drop and heat transfer than the ratio of the length of protrusion to module length. As the height of protrusion increases, pressure drop and heat transfer increase, but if the height of protrusion exceeds 2/3 of the channel height, there is a substantial pressure drop. The results also show that the optimal length and height of protrusion are half of the module length and half of the channel height, respectively.

• Imaging Science in Dentistry
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• 제50권4호
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• pp.309-318
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• 2020

Purpose: This study investigated correlations between findings on panoramic radiographs and cone-beam computed tomography (CBCT) to assess the relationship between the maxillary sinus floor and the roots of maxillary posterior teeth. In addition, radiographic signs indicating actual root protrusion into the maxillary sinus were evaluated on panoramic radiographs. Materials and Methods: Paired panoramic radiographs and CBCT images from 305 subjects were analyzed. This analysis classified 2,440 maxillary premolars and molars according to their relationship with the maxillary sinus floor on panoramic radiographs and CBCT images. In addition, interruption of the sinus floor was examined on panoramic radiographs. Results: Root protrusion into the maxillary sinus occurred most frequently in the mesiobuccal roots of the second molars. The classification according to panoramic radiographs and CBCT images was the same in more than 90% of cases when there was no contact between the root apex and the sinus floor. When the panoramic radiograph showed root protrusion into the sinus, the CBCT images showed the same classification in 67.5% of second molars, 48.8% of first molars, and 53.3% of second premolars. There was a statistically significant relationship between interruption of the sinus floor on panoramic radiographs and root protrusion into the sinus on CBCT images. Conclusion: The presence of root protrusion into the sinus on panoramic radiographs demonstrated a moderate ability to predict root protrusion into the maxillary sinus. Interruption of the maxillary sinus floor could be considered an indicator of actual root protrusion into the maxillary sinus.

• 한국의학물리학회지:의학물리
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• 제20권4호
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• pp.208-215
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• 2009

2차원의 영상을 이용한 돌출형 전립선 비대증의 부피 평가방법에서 돌출부위를 포함시킬 경우와 포함시키지 않을 경우의 부피변화를 3차원 볼륨 렌더링(volume rendering, VR)을 이용하여 비교 평가하고자 한다. 돌출형 전립선 부피측정을 위한 가상 전립선 모델은 곤약을 이용해 임의로 평균 1 cm 정도로 돌출되도록 하여 10 ml에서 각각 10 ml씩 부피를 변화시켜 100 ml까지 총 10 개의 모델을 제작하였다. 이 때 제작된 모델의 부피측정은 64 channel 전산화단층촬영(computed tomography, CT)과 3.0 Tesla 자기공명영상(magnetic resonance image, MRI)을 이용하여 획득된 3차원 볼륨 영상자료로 계측하였다. 산출한 CT와 MRI영상들의 3차원 볼륨데이터 근접성 평가를 위해 wilcoxon 부호순위(signed rank) 검정을 하였다. 또한 획득한 영상자료는 3차원 영상처리를 통하여 볼륨 렌더링으로 재구성한 후 타원체부피공식법을 이용하여 돌출부위를 포함시킬 때와 포함하지 않을 때의 부피를 구하였다. 이 때 돌출 유무에 따라 각각 측정된 부피와 3차원 볼륨 렌더링의 부피를 wilcoxon 부호순위(signed rank) 검정을 사용하여 유의성을 평가했으며 상관계수(pearson's correlation coefficient, r)를 사용하여 상관관계를 분석하였다. 계측된 가상 전립선 모델의 돌출부위길이는 CT에서 $0.90{\pm}0.18\;mm$, MRI에서 $0.75{\pm}0.11\;mm$이었으며, CT와 MRI에서 계측된 3차원 영상 부피의 p-value는 0.414로 유의한 차이는 없었다. 그러나 MRI에서 측정된 3차원 영상 부피와 2차원 영상에서 돌출부위를 포함시킬 때의 p-value는 0.005인 반면 포함하지 않을 때의 p-value는 0.139로 나타났으며, CT에서도 측정된 3차원 영상 부피와 2차원 영상에서 돌출부위를 포함시킬 때의 p-value는 0.005인 반면 포함하지 않을 때의 p-value는 0.057로 나타났다. 돌출형 전립선의 부피측정은 돌출부위를 제외하고 상하길이를 측정하는 것이 3차원 볼륨 렌더링에 의한 부피 값과 더 가까운 부피 값을 얻을 수 있었다.

• 대한전기학회논문지
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• 제39권9호
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• pp.956-963
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• 1990

The general shapes of prebreakdown pulses in a discharge gap were calculated and the current pulses due to avalanche were detected in SF6 by changing the polarity of the protrusion placed on an electrode at pressures up to about 400 Kpa. The mathematical model of prebreakdown pulse development with a negative protrusion shows agreement with the observed pulses. No evidence of intense bursts of field-emitted electrons was observed. Breakdown probably results from a single avalanche developing to a critical size. However the calculated shape of prebreakdown current pulse does not agree with the observed pulses with a positive protrusion. The breakdown is preceded by multiple avalanche development at pressures less than about 200 Kpa. This observation has been interpreted as due to the formation of negative ions following photoionization in the gas which drift into the critical volume near a positive protrusion.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2002년도 제7차 학술대회 초록집
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• pp.138-138
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• 2002

To determine the accuracy of magnetic resonance (MR) imaging for discrimination between intervertebral disk extrusion versus protrusion. MR images of 80 patients who had MR imaging of the spine and confirmed as intervertebral disk extrusion or protrusion were retrospectively reviewed by an experienced musculoskeletal radiologist. A 1.5-T scanner was used. After review of medical records, MR findings of disk extrusion and protrusion were compared using the chi-square test. Intraobserver agreement for differentiation of disk extrusion from protrusion was calculated by using coefficient.

• Journal of the Optical Society of Korea
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• 제17권2호
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• pp.200-204
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• 2013

We propose a cell structure for the fast switching of liquid crystals by the fringe field. By forming protrusion between patterned electrodes, we can obtain enhancement of response time. The protrusion reduces the effective cell gap, with which a fast response time can be realized. There is little decrease in the transmittance because the protrusion is located between patterned electrodes. We confirmed that the total response time can be decreased by 33% with little loss of the transmittance by optimizing the shape of the protrusion structure.

• Journal of Advanced Marine Engineering and Technology
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• 제36권1호
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• pp.57-63
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• 2012

열전달 향상을 위하여 이차유동을 발생시켜 열전달을 증가시키는 방법에는 여러 가지가 있다. 본 연구에서는 수평채널에 딤플과 돌출을 설치하여 각각의 깊이와 높이를 변화시켰을 때의 압력강하 및 열전달 특성을 수치해석을 통하여 연구하였다. 딤플과 돌출은 수평채널의 윗면과 아래면 에 설치되었으며, 깊이 및 높이를 0.125, 0.25, 0.25, 0.3, 0.375로 하였다. 딤플의 경우, 후면부에서 높은 Nusselt 수가 나타났고 깊이가 커질수록 평균 Nusselt 수가 감소하였다. 돌출의 경우, 전면부에서 높은 Nusselt 수가 나타났고 높이가 커질수록 Nusselt 수가 증가하였다. 딤플과 돌출 모두 유속이 증가함에 따라 열전달이 향상되는 경향을 보였지만 성능계수는 감소하였다. 성능계수는 유속이 낮은 영역에서 가장 크게 나타났다.

• 마이크로전자및패키징학회지
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• 제20권2호
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• pp.65-74
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• 2013

Through-Silicon Via (TSV) 기술은 3차원 적층 패키징를 위한 핵심 기술로서 큰 관심을 받고 있다. 그러나 TSV 기술은 아직 다양한 공정상의 문제와 신뢰성 문제를 해결해야 하는 난제가 남아 있다. 특히 구리 비아(via)와 실리콘 기판의 큰 열팽창계수의 차이로 인한 열응력은 계면 박리, 크랙 발생, 구리 protrusion 등 다양한 신뢰성 문제를 발생시킨다. 본 연구에서는 구리 TSV 구조의 열응력을 수치해석을 이용하여 분석하였으며, 3차원 TSV 비아와 실리콘 기판의 응력 및 변형을 해석하였다. 비아의 크기, 비아와 비아 사이의 간격 및 비아의 밀도가 TSV 구조의 응력에 미치는 영향을 분석하였으며, 또한 어닐링(annealing) 온도 및 비아의 크기가 구리 protrusion에 미치는 영향을 관찰하였다. 구리 TSV 구조의 신뢰성을 향상시키기 위해서는 적절한 비아와 비아 사이의 간격을 유지한 상태에서, 비아의 크기 및 비아의 밀도는 작아야 한다. 또한 구리 protrusion을 감소시키기 위해서는 비아의 크기 및 어닐링 공정과 같은 공정의 온도를 낮추어야 한다. 본 연구의 결과는 TSV 구조의 열응력과 관련된 신뢰성 이슈를 이해하고, TSV 구조의 설계 가이드라인을 제공하는데 도움을 줄 수 있을 것으로 판단된다.