• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1389-1394
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• 2004

Experiments were done for the unsteady flow in a counter rotating axial flow fan near peak efficiency and stall point. Flow fields in a counter rotating axial flow fan were measured at cross-sectional planes of the upstream and downstream of each rotor. Cross sectional passage flow patterns were investigated through the acquired data by the $45^{\circ}$ inclined hot-wire. Comparison of flow characteristics between two different operating conditions such as tip vortex, secondary flow and turbulence intensity were performed through the analyses of axial, radial and tangential velocity distributions. As a result, tip vortex and secondary flows are enforced and measured obviously at stall point.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.544-549
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• 2003

When a shock wave arrives at an open end of tube, an impulse wave is discharged from the tube exit and causes serious noise and vibration problems. In the current study, the effect of the cross-sectional area of tube on the impulse wave is numerically investigated using a CFD method. The Harten-Yee's total variation diminishing(TVD) scheme is used to solve the axisymmetric, two-dimensional, unsteady, compressible Euler equations. With three different cross-sectional areas of tube, the Mach number of the incident shock wave $M_{s}$ is varied between 1.01 and 1.5. The results obtained show that the directivity and magnitude of impulse wave strongly depend upon the Mach number of incident shock wave and are influenced by the tube area. It is also known that the tube cross-sectional area significantly affects the magnitude of impulse wave at or near the tube axis.

• 한국가정과학회지
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• 제2권1호
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• pp.110-113
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• 1999

Clothing shape is principally described in seven factors that are composed of clothing design, clothing material, clothing size, pattern design, sewing method and body motion etc. The aims of this study was to measurement out-line space-shape variation of clothing fitness with body by using the image processing. The subjects for direct anthropometric measurements were 248 female college students aged from 19 to 22. The data were statistically analyzed by principal analysis and cluster analysis. The results selected one somatotype. for the out-line space-shape variation of clothing fitness with body, there dimensional clothing shapes measured. and cross-sectional clothing shape obtained by the measurement was considered to be space wave form. The out-line space-shape variation of clothing fitness with body was observed between the node number and amplitudes of clothing wave form, and node number was determined at the maxim of space-shape amplitude, and the space-shape amplitudes have related with aspect ratio of cross-sectional shape. (Korean J of Human Ecology 2(1) :110-113, 1999)

• 설비공학논문집
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• 제16권9호
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• pp.804-810
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• 2004

This paper reports the characteristics of the three dimensional turbulent flow by numerical method in the 180 degree bends with increasing cross-sectional area. Calculated pressure and velocity, Reynolds stress distributions are compared to the experimental data. Turbulence model employed are low Reynolds number $textsc{k}$-$\varepsilon$ model and algebraic stress model(ASM). The results show that the main vortex generated from the inlet part of the bend maintained to outlet of the bend and vortices are continually developed at the inner wall region. The distribution of turbulent kinetic energy along the bend are increase up to 120$^{\circ}$ because of increment of cross-sectional area. Secondary flow strength of the flow is lower about 60% than that of square duct flow.

• The Journal of Korean Physical Therapy
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• 제26권5호
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• pp.324-330
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• 2014

Purpose: The aim of the current study was to compare the muscle architecture of lower extremity using rehabilitative ultrasound imaging (RUSI) in young adults in Seoul and Hanoi. Methods: The study design was a comparative study of muscle cross-sectional area of lower extremity. Sixty healthy young subjects (Seoul group: 30, Hanoi group: 30) participated in this study. Real-time B-mode RUSI with a 7.5MHz linear transducer was used for measurement of cross-sectional area, pennation angle, and muscle thickness of the rectus femoris, tibialis anterior, and medial gastrocnemius muscles. Independent t-test was used for statistical analysis. Results: Significant difference in cross sectional area of rectus femoris was observed between Korean young adults and Hanoi young adults (p<0.01). Muscle thickness and pennation angle of tibialis anterior in Korean young adults were greater than in Hanoi young adults (p<0.01). In addition, the muscle thickness and pennation angle of the medial part of gastrocnemius muscle were greater in Korean young adults than in Hanoi young adults (p<0.01). In addition, in the results for gender, men had larger muscle architectures than women in both groups (p<0.01). Conclusion: This study, using RUSI, showed significant difference in muscle architectures of lower extremity in a diverse group of young adults RUSI.

• 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.

• Asian Journal for Public Opinion Research
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• 제8권4호
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• pp.478-492
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• 2020

The COVID-19 global health crisis has affected the mental and psychological health and well-being of the people around the world. However, little is known about the impact of COVID-19 among Filipino teachers. This study was conducted to determine the impact of the COVID-19 pandemic on the quality of life (QoL) of professional teachers in the Philippines. A descriptive cross-sectional study was used involving 139 licensed professional teachers. The COVID-19 Impact on Quality of Life (COV19-QoL) was the primary measure used in this study. Descriptive statistics, t-test, and one-way ANOVA were the statistical tools employed to analyze the data. Results indicated a moderate COVID-19 impact on the QoL of the teachers. There was a significant difference in the impact of COVID-19 on QoL by degree program. However, the impact of COVID-19 on QoL did not significantly differ by age, sex, marital status, employment status, monthly salary, presence of a COVID-19 case near their residence, personal knowledge of someone who was infected or died of COVID-19, presence of a medical condition, and perceived threat. The psychological well-being and QoL of teachers must be recognized and teachers must be provided with support as they continue to adapt to the impact brought by the COVID-19 pandemic. This study contributes to the growing literature on the impact of the pandemic.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.550-555
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• 2003

When a shock wave arrives at an open end of tube, an impulse wave is discharged from the tube exit and complicated flow is formed near tube exit. The flow field is influenced by the cross-sectional geometry of tube exit, such as circular, square, rectangular, trapezoid and etc. In the current study, three-dimensional propagation characteristics of impulse wave discharged from the tube exit with non-circular cross section are numerically investigated using a CFD method. Total variation diminishing (TVD) scheme is used to solve the three-dimensional, unsteady, compressible Euler equations. Computations are performed for the Mach numbers of the incident shock wave $M_{s}$ below 1.5. The results obtained show that the peak pressure of the impulse wave and propagation directivity depends on the cross-sectional geometry of tube exit and the Mach number of incident shock wave.

• 한국화재소방학회논문지
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• 제25권6호
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• pp.83-88
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• 2011

본 연구에서는 전기기기 및 가전기기 등의 배선으로 사용되는 비닐코드의 구조 및 특성을 제시하고, 에너지원의 종류에 따라 소손된 비닐평형코드(VFF, $1.25mm^2$)의 실체 사진 및 용융된 도체의 금속 단면 구조를 분석하였다. 정상 VFF는 소선 여러 가닥을 꼬아서 제작되었으며, 도체의 표면은 적갈색이다. 또한 도체의 금속 조직 분석에서 그레인이 연신된 것을 알 수 있었다. 일반 화염에 의해 소손된 VFF의 표면은 절연물이 탄화되어 도체의 표면에 융착되었고, 윤기가 없는 것을 알 수 있었다. 또한 용융 부분의 단면 구조 분석에서 일정한 모양의 보이드가 형성되었고, 전선 고유의 연신 구조는 확인할 수 없었다. 통전중인 VFF에 외부 화염이 인가되어 소손된 용융 도체의 단면 분석에서 전선 고유의 연신 구조는 없었고, 불규칙적인 보이드 및 주상 조직 등이 성장한 것을 알 수 있었다. 과전류에 의해 소손된 VFF는 표면이 고르게 탄화되었으며, 용융된 도체의 단면 구조 분석에서 수지상 조직의 성장이 확인되었다. 단락에 의해 용융된 VFF의 특성 분석에서 표면의 일부가 오염되었지만 약간의 윤기가 있고, 용융되어 재결합한 부분이 둥근 모양을 나타냈다. 또한 금속 현미경을 이용한 단면 구조 분석에서 경계면 및 주상 조직 등이 확인되었고, 용융된 도체 이외의 부분에서는 정상 구리와 같은 비정질체인 구조가 확인되었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
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• pp.98-106
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• 1999

In this study cold rolling process for the irregular cross-sectional shape has been investigated. The product analyzed in present study is the steel cutter, which is frequently used to cut the desired shape on leather. Because steel cutter always has a irregular cross-section, after rolling process the workpiece is severely bended to every direction. The bending of the workpiece affects the processed performed after rolling such as heat treatment and grinding, then that of the workpiece becomes more severe. In this study, therefore, to prevent the bending of the workpiece to the left and right sides. rigid-plastic finite element method has been utilized and in order to find optimal roll geometry rapidly, one dimensional equal interval search technique has been also introduced. By using both rigid plastic finite element method and optimum technique, cold rolling process for the irregular cross-sectional shape has been successfully investigated.