• 한국터널지하공간학회 논문집
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• 제14권2호
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• pp.141-157
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• 2012

TBM 공법 적용을 위한 도로터널 단면의 국내 외 설계사례와 시공사례 및 터널단면 설계기준을 조사 분석하였다. 교통량에 따라 차로수의 규모 및 내부형상(단층 혹은 복층)이 상이하였고, 상 하부의 여유공간은 환기, 방재시설 및 유지관리 공간 등으로 다양하게 활용하고 있음을 확인하였다. TBM도로터널의 구성요소별 면적비를 확인하기 위하여 2차로 규모의 표준단면을 가정하고, 길어깨 폭원변화에 따른 내공단면 구성요소(시설한계 수용공간, 상부여유공간, 하부여유공간)의 단면적비를 분석하였다. 아울러 도로터널에 필수적으로 설치되는 차도 슬래브의 지지형식별 소요두께를 구조해석을 통하여 산정하였고, 산정된 벽체 및 슬래브 두께와 하부 여유공간의 상관관계를 분석하여 유효단면적 범위를 제시하였다.

• 치과방사선
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• 제28권1호
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• pp.111-126
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• 1998

In this study, radiographic evaluation was made using panoramic radiography and cross-sectional tomography of SCANORA/sup (R)/ in male and female adults in their 20's on the relationship between the maxillary sinus floor and the apex of the maxillary molar, to test the accuracy and effectiveness of the cross-sectional tomography, and to use this information in the assessment of preop. and postop. root canal treatment, apical surgery, extraction and implantology. Forty-one adults with an average age of 24.4 years were studied using panoramic radiography and cross-sectional tomography. In panoramic view and cross-sectional view, the position of the apices of maxillary molars were classified as separated, contacted, or protruded type; the general shape of the maxillary sinus floor was evaluated horizontally and vertically from cross-sectional tomography. The accuracy of each radiography was tested using maxilla from 5 fresh cadavers from the Anatomy Lab at Yonsei University Dental College, and panoramic view and cross-sectional tomography were taken in the same condition as with the patients. The results were as follows: 1. Panoramic view and cross-sectional view were taken in the maxilla specimen, and the actual distance between the maxillary sinus floor and the tooth apices were measured in the specimen; the median values of the distance from the tooth apices to the maxillary sinus floor in the panoramic view, cross-sectional view and in the actual maxilla specimen were 2.83 mm, 4.51mm, and 4.l5mm, respectively. In the cross-sectional view, the measured distance was close to the actual distance but in the panoramic view, the measured distance was far from the actual distance. 2. When the results of the panoramic view and cross-sectional view were compared, 40.5％ of the results agreed with each other in the two radiographic methods and buccal roots of the 2nd molar were the closest to the maxillary sinus floor in the cross-sectional tomography. 3. In cross-sectional view, when the vertical relationship of the maxillary sinus floor and maxillary roots was assessed, in 1st molars, type II (the sinus floor that extends down to the buccolingual furcation area) was predominant, while in 2nd molars, type I (the sinus floor located above the level connecting the buccal and lingual apices) was predominant. In the horizontal relationship, in 1st molars, type II (the lowest floor of the maxillary sinus located in between the buccal and lingual roots) was predominant; in 2nd molars, type I (the lowest floor of the maxillary sinus located on the buccal side of the buccal roots) and type II appeared in similar frequency. In conclusion, the SCANORA/sup (R)/ cross-sectional tomography was more effective than the frequently used panoramic view, in that the relationship of the maxillary molars and maxillary sinus floor can be evaluated more accurately and the buccolingual cross-sectional view can also be observed. And maxillary sinus floor that was close to maxillary 2nd molar had tendency to be located on buccal side than that close to 1st molar. Therefore, cross-sectional tomography is an effective and accurate method to evaluate the position of the teeth in relation to the sinus floor preoperative and can be easily used to diagnose localized periapical lesions. Also, the image quality obtained was quite satisfactory.

• 대한간호학회지
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• 제25권2호
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• pp.193-209
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• 1995

The purpose of this study was to determine the effect of intermittent low - intensity, short duration exercise during hindlimb suspension on the mass, relative weight, myofibrillar protein content, cross-sectional area of Type I and Type II fibers and SDH activity in Type II(plantaris) muscle. To examine the effectiveness of intermittent low-intensity, short duration exercise on mass, myofibrillar protein content and fiber size, the hindlimbs of adult female Wistar rats were suspended(HS) and half of these rats walked on a treadmill for 45 min/day(9 min every 2h) at 5m /min and a 15$^{\circ}$grade (HS-EX). Plantaris wet weight was 19.67% significantly smaller(p<0.005) and relative plantaris weight was 6.25% smaller compared with those of control rats following seven days of hindlimb suspension. Plantaris wet weight and relative plantaris weight increased by 27.66%, 12.22% each through intermit-tent exercise during hindlimb suspension(p<0.005, p<0.05), moreover, plantaris wet weight and relative plantaris weight of the HS-EX rats were similar to those of control rats. Soleus wet weight and relative soleus weight decreased significantly by 31% and 22.0% in the HS rats(p<0.05). Soleus wet weight and relative soleus weight increased by 10.41%, 25.64% respectively through intermittent ex-ercise during hindlimb suspension, furthermore, soleus wet weight and relative weight of the HS-EX rats were closer to those of control rats. Myofibrillar protein content of plantaris and soleus decreased significantly by 51.49%, 59.65% each, following seven days of hindlimb suspension (p<0.005) Myofibrillar protein content of plantaris and soleus increased by 51.79%, 75.47% each with significance through intermittent exercise during hindlimb suspension(p<0.005). Myofibrillar protein content of plantaris and soleus in HS-EX rats was smaller than that of control rats. No change was observed in fiber type percentage following 1 week of hindlimb suspension or exercise during hindlimb suspension. The type I fiber cross-sectional area of both soleus and plantaris muscle was 18.72% and 41.07% lower in the HS than that of the controls (p<0.05, p<.001), that of both muscles was 6.60% and 29. 3％ greater in the HS-EX than that of the HS rats. HS plus intermittent low- intensity short duration exercise resulted in Type I fiber cross-sectional area closer to the controls. Type II fiber cross-sectional area of both plantaris and soleus muscle was 22.45% and 22.58% sl nailer in the HS than in the controls, that of both muschles in the HS-EX was 14.10%, 5.78% greater than HS. Intermittent exercise during hindlimb suspension resulted in Type I, II fiber cross-sectional area closer to the control value. There was no change in SDH activity following 1week of hindlimb suspension or exercise during hindlimb suspension in the plantaris muscle. The results suggest that intermittent low intensity short duration exercise can ameliorate Type II muscular atrophy Induced by hindlimb suspension.

• 한국산학기술학회논문지
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• 제20권4호
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• pp.619-625
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• 2019

저심도 터널에서는 온도차에 의한 부력을 이용한 자연배기시스템이 많이 사용되고 있지만 이는 연기배출을 인위적으로 조절할 수 없다. 그러므로 자연배기시스템에서는 수직환기구에서 연기 배출량이 설계된 연기 배출량보다 적어지는 Plug-holing 현상을 고려한 설계가 필수적이다. Plug-holing 현상은 터널과 수직환기구의 형상 위치, 화원의 위치와 발열량 등에 영향을 받는다. 본 연구에서는 터널과 자연 환기구의 단면적 비와 화원의 열방출률이 자연배기시스템에서 발생하는 Plug-holing 현상에 미치는 영향에 대하여 실험적으로 분석하였다. 1/20 크기로 축소시킨 실험모델에서 터널과 수직환기구의 종횡비는 고정시키고 터널과 수직환기구의 단면적 비를 달리하여 Plug-holing 현상에 미치는 영향을 확인하였다. 화원의 열방출율은 0.55 kW, 0.98 kW, 1.67 kW로 고정시켰다. 실험결과, 연기 경계층온도와 수직환기구 내의 온도와의 비교를 통한 Plug-holing 발생을 판단하였고, 터널과 수직환기구의 단면적 비가 증가함에 따라서 수직환기구 하부의 유동과 온도분포 특성이 변함을 확인하였다. 터널 화재 시 Plug-holing 현상은 터널과 수직환기구의 단면적 비에 영향을 받으며 단면적 비가 클수록 Plug-holing 발생 가능성이 증가하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제3권1호
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• pp.35-39
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• 2001

The optimum cross-sectional area profile of gas-cooled high-temperature superconductor(HTS) current lead is analyzed to have minimum helium boil-off rate. The conventional constant area HTS lead has much higher helium consumption than the optimum HTS lead considered in this study. The optimum HTS lead has variable cross-sectional area to have constant satiety factor. An analytical formula of optimum shape of lead and temperature profile are obtained. For multi-stacking HTS current leads, the optimum tape lengths and minimum heat dissipation rate are also formulated. The developed formulations are applied to the Bi-2223 material, and the differences between constant area, constant safety-factor, and multi-stacking current leads are discussed.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2001년도 학술대회 논문집
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• pp.84-88
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• 2001

The optimum cross-sectional area Profile of gas-cooled high-temperature superconductor (HTS) current lead is analyzed to have minimum helium boil-off rate. The conventional constant area HTS lead has much higher helium consumption than the optimum HTS lead considered in this study. The optimum HTS lead has variable cross-sectional area to have constant safety factor. An analytical formula of optimum shape of lead and temperature profile are obtained. For multi-step HTS current leads, the optimum tape lengths and minimum heat dissipation rate are also formulated. The developed formulations are applied to the Bi-2223 material, and the differences between constant area, constant safety-factor, and multi-step current leads are discussed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.591-596
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• 2000

Flow through compliant tubes with linear taper in wall thickness is numerically simulated by finite element analysis. Two models are examined: a planar two-dimensional channel, and an axisymmetric tube. For verification of the numerical method, flow through a compliant stenotic vessel is simulated and compared to existing experimental data. Computational results for an axisymmetric tube show that as cross-sectional area falls with a reduction in downstream pressure, flow rate increases and reaches a maximum when the speed index (mean velocity divided by wave speed) is near unity at the point of minimum cross-section area, indicative of wave speed flow limitation or "choking" (flow speed equals wave speed) in previous one-dimensional studies. For further reductions in downstream pressure, flow rate decreases. Cross-sectional narrowing is significant but localized. When the ratio of downstream-to-upstream wall thickness is ${\le}$ 2 the area throat is located near the downstream end; as wall taper is increased to ${\ge}$ 3 the constriction moves to the upstream end of the tube. In the planar two-dimensional channel, area reduction and flow limitation are also observed when outlet pressure is decreased. In contrast to the axisymmetric case, however, the elastic wall in the two-dimensional channel forms a smooth concave surface with the area throat located near the mid-point of the elastic wall. Though flow rate reaches a maximum and then falls, the flow does not appear to be choked.

• 한국정밀공학회지
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• 제27권4호
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• pp.102-108
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• 2010

Projection microstereolithography is a process of fabricating a micro-structure by using dynamic mask such as digital micromirror device(DMD). DMD shapes the beam into cross-sectional image of structure. Photocurable resin is cured by the beam and stacked layer on top of layer. It is difficult to deliver the beam from the DMD to the photocurable resin without any distortions. We assume that the beam exposed to the resin by 1 pixel of DMD has Gaussian distribution, so the shaped beam reflected by the DMD affects its neighboring area. Curing pattern corresponding to a cross-sectional images is predicted by superposition of pixels of Gaussian distribution and it is similar to cured shape.

• Physical Therapy Rehabilitation Science
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• 제1권1호
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• pp.28-32
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• 2012

Objective: The purpose of this study is to compare chronic low back pain patients' pain provocation position so as to identify the relevance with lumbar stabilizing muscles atrophy and pain provocation position. Design: Cross-sectional study. Methods: Fifty five chronic low back pain patients were participated in this study. Subjects were eligible for study participation if they were 35-55 years old and had experienced low back pain for more than 3 months. Subjects were questioned about pain and pain provocation test were done. And then they were inspected their cross sectional area (CSA) of lumbar muscles (erector spinae, iliopsoas, and multifidus) by using computed tomography. Analyze the relevance through the result data with painful area, aspect of pain and pain provocation position. Results: CSA of erector spinae showed significant decrease on ipsilateral extension position (p<0.05). Iliopsoas muscle showed significant decrease on contralateral position (p<0.05). Multifidus showed significant decrease on the position of contralateral extension and contralateral flexion (p<0.05). Conclusions: Based on the results of our study, it may be possible to evaluate muscle atrophy by assessing causing position.

• Journal of Korean Neurosurgical Society
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• 제50권3호
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• pp.201-204
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• 2011

Objective : To quantitatively evaluate the asymmetry of the multifidus and psoas muscles in unilateral sciatica caused by lumbar disc herniation using magnetic resonance imaging (MRI). Methods : Seventy-six patients who underwent open microdiscectomy for unilateral L5 radiculopathy caused by disc herniation at the L4-5 level were enrolled, of which 39 patients (51.3%) had a symptom duration of 1 month or less (group A), and 37 (48.7%) had a symptom duration of 3 months or more (group B). The cross-sectional areas (CSAs) of the multifidus and psoas muscles were measured at the mid-portion of the L4-5 disc level on axial MRI, and compared between the diseased and normal sides in each group. Results : The mean symptom duration was $0.6{\pm}0.4$ months and $5.4{\pm}2.7$ months for groups A and B, respectively (p<0.001). There were no differences in the demographics between the 2 groups. There was a significant difference in the CSA of the multifidus muscle between the diseased and normal sides (p<0.01) in group B. In contrast, no significant multifidus muscle asymmetry was found in group A. The CSA of the psoas muscle was not affected by disc herniation in either group. Conclusion : The CSA of the multifidus muscle was reduced by lumbar disc herniation when symptom duration was 3 months or more.