• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1999.06a
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• pp.105-110
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• 1999

여러 종류의 작업장은 생산공정상의 필요나 일기변화에 따가 온습조건에 많은 차이가 있으며, 인체에 불리한 열환경조건이 조성되는 경우가 있다. 일반적으로 열피로(heat stress)와 열장애(heat strain)는 근로자의 안전과 보건을 평가하는데 필요하며, 열피로는 열적영향을 발생시키는 원인을 말하고, 열장애는 열에 의해 발생되는 결과로서 생리적인 부하를 의미하게 된다. 신체내부에서 발생되는 열은 열피로의 한가지 형태이고, 따라서 이것을 측정하는 것은 아주 본질적인 사항이다. (중략)

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.855-858
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• 2010

본 연구는 발달적 위기에 놓여있는 중년여성의 피로도와 스트레스 저항력 그리고 정서와의 상관관계를 알아보기 위하여 뇌신경 생리학적 지표인 뇌파 측정을 이용하여 분석해 보고자 하였다. 2005년 3월부터 2009년 6월까지 한국정신과학연구소에 뇌파 측정을 의뢰한 우리나라 중년여성 4403명(35세~65세)을 기준으로 선정된 뇌기능 지수(긴장도, 항스트레스지수, 정서지수)를 시계열 선형분석과 상관분석으로 한 결과 중년여성의 피로도, 스트레스 저항력 그리고 정서에는 밀접한 관계가 있었다. 그러므로 사회적으로나 가정적으로 성숙하고 책임감 있는 중년여성의 역할이 필요한 현대사회에서, 중년기의 심리적 생리적 문제에 적극적으로 대처하는 것이 개인생활은 물론 가족의 원만한 기능과 안녕을 유지, 증진하는데 반드시 필요하다.

• Physical Therapy Korea
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• v.5 no.4
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• pp.9-19
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• 1998

연구목적 이 연구의 목적은 피로유발수축후 장딴지근과 가자미근의 근전도 power spectrum 중앙경항치를 비교 검사하는 것이다. 실험대상 열 여섯명의 자원자(남자 10, 여자 6)를 대상으로 하였다. 남자 대상자의 연령범위는 25세에서 33세(평균 $28.6{\pm}2.5$)였고 여자 대상자의 연령범위는 26세에서 31세($27.8{\pm}1.9$)였다. 실험방법 실험대상자는 피로유발수축전후 50% 최대등척성근수축을 수행하였다. 자료수집과 분석을 위해 LabVIEW 소프트웨어를 사용하였다. 결과 t-검정결과 내측 장딴지근에서는 피로유발수축후 주파수의 중위값과 평균이 통계적으로 유의하게 감소하였으나 가자미근에서는 통계적으로 유의한 차이가 없었다. t-검정결과 두 근육간 주파수 감소의 차이는 통계적으로 유의한 차이가 있었다. 토의 및 결론 이 결과들은 피로유발수축후 근전도 power spectrum 중앙경향치가 저주파대역으로 감소함을 나타내었다. 이 연구는 중앙주파수와 평균주파수가 피로지수로서의 신뢰도와 타당도가 뛰어나며 객관적 측정과 훈련효과 평가로 사용할수 있음을 보였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1145-1150
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• 2011

The purpose of this study was to determine the relationships between fatigue, stress resistance and emotion in middle aged women under the developmental crisis using a brain wave measurement which is a cranial physiological index. From March 2005 to June 2009, women aged between 35 and 65 (N=4402) who volunteered for a brain wave test at the KRIJUS( Korea Research Institute of Jungshin Science) were monitored the brain function quotient (tension degree, anti-stress quotient and emotional quotient). Correlation and time-series linear analysis revealed significantly the relationships between fatigue, stress resistance and emotion. Also, according to the emotional propensity, cheerful propensity was higher in the cheerful and depressed propensity, positive propensity was higher in the positive and negative propensity, during the whole test, cheerful and positive propensity was higher. Therefore, it is necessary to increase the quality of life by decreasing fatigue and stress level of the middle-aged women to maintain and increase their individual health and the better family relationship.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.1
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• pp.50-56
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• 2007

Exhaust manifold is generally subjected to thermal cycle loadings ; at hot condition, large compressive plastic deformations are generated, and at cold condition, tensile stresses are remained in highly deformed critical zones. These phenomena originate from the fact that thermal expansions of the runners are restricted by inlet flange clamped to the cylinder head, because the former is less stiff than the latter and, the temperature of the inlet flange is lower than that of the runners. Since the failure of an exhaust manifold is mainly caused by geometric constraints between the cylinder head and the manifold, the thermal stress can be controlled by geometric factors. The generic geometric factors include the inter distance (2R), the distance from the head to the outlet (L), the tube diameter(d) and the tube thickness (t). This criteria based on elastic analysis up to onset of yield apparently indicate that the pre-stress also reduces the factor; however, high temperature relaxation may reduce this effect at later operation stage.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.245-247
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• 2017

A turbine wheel undergoes high heat flux and centrifugal force when a gas turbine starts. The temperature and stress of the turbine wheel increase rapidly, and the time point and rate of them may not coincident. The difference of heating and rotating rates influences the life of turbine wheel. We conducted thermo-mechanical fatigue analysis with finite element methods to study the influence. The low acceleration and deceleration of the wheel extends the life. If the turbine wheel decelerate faster than cooling, the life increases.

• Journal of Biomedical Engineering Research
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• v.23 no.1
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• pp.9-16
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• 2002

Localized muscle fatigue can be identified by a downward shift of the EMG frequency typically represented by a fall in the median frequency The Present experimental study was Performed to investigate the time change of the median frequency and the muscle torque during maximal isometric back extension exercises at different exercise angles (0$^{\circ}$, 12$^{\circ}$, 36$^{\circ}$and 72$^{\circ}$) Twenty heath subjects (mean age : 24.35 $\pm$ 2.70) were Participated in this study Median frequency was extracted from EMG signals by employing the fast Fourier transform. Initial median frequency and the slope of median frequency was not significantly correlated with the muscle torque. Pearson's Product moment correlation was used to quantify the relationship between slopes of median frequency and torque. The results may suggest that the exorcise angle during maximal isometric back extension exercises does not affect the slopes of the median frequency and torque, and y-intercept of the median frequency among exercise angles There was no significant correlation between slopes of median frequency and torque. But there was a moderate correlation between median frequency and torque at each exercise angle. In conclusion, the exercise angle during maximal isometric back extension exercise is not a direct effect on slopes of median frequency and torque. But results showed that the shift of median frequency and torque shift were highly correlated in all subjects.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.1 s.34
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• pp.53-58
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• 2005

We researched damage formation and failure mechanism under DC(direct current) and AC(alternative current) in order to estimate reliability of Cu interconnects in ULSI. Higher current density and temperature induces more short TTF(time to failure) during interconnects carry DC. Measurement reveals that Cu electromigration has activation energy of 0.96eV and current density exponent value of 4. Thermal fatigue is occurred under DC, and higher frequency and ${\Delta}$T value gives more severe damage during interconnects carry AC Through failure morphology analysis with respect to texture, we observed that damages had grown widely and facetted grains had appeared in (100)grain but damages in (111) had grown thickness direction of line and had induced a failure rapidly.