• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 추계학술대회 논문집
• /
• pp.747-750
• /
• 1997

Using complex potentials and the concept of repeated roots for general solutions, logarithmic stress singularities and coefficient vectors for v-notched cracks in isotropic dissimilar materials are evaluated and demonstrated to have no influence on the logarithmic stress singularities.

• 대한치과교정학회지
• /
• 제15권2호
• /
• pp.211-227
• /
• 1985

The purpose of this study was to analyze the stress distribution and the displacement in the maxillary complex after the application of the three kinds of the head gear. (high pull head gear, straight pull head gear, cervical pull head gear.) Orthopedic force, 300 gram, was applied to the maxilla of the dry human skull in a high, straight and cervical direction. The stress distribution and the displacement within the maxillary complex was analyzed by a 3-dimensional finite element method. The results were as follow: 1. In won, the stress of conical pull head gear was the greatest stress and straight pull head gear was the medium stress and high pull head gear was the least stress. 2. The compressive stress was observed on the anterior portion of premaxilla, especially anterior nasal spine area, when the three kinds of head gear were applied to the dry kuman skull. 3. It appeared that the stress of the anterior portion of the zygomatic bone was greater than the posterior portion in the case of three kinds of head gear application and compressive stress was noted only at the below of the frontozygomatic suture of the zygomatic bone. 4. The backward, upward, sideward displacement of the alveolar area was observed in a high pull head gear application but in the case of straight pull head gear and cervical pull head gear application, the backward, downward, sideward displacement was observed. 5. The forward, downward, sideward displacement was observed on the midpalatine suture and premaxilla on the sagittal plane and transverse palatine suture in the case of three kinds of headgear application.

• 한국정밀공학회지
• /
• 제20권9호
• /
• pp.159-165
• /
• 2003

Most engineers interested in stress singularities have focused mainly on the research of power stress singularities for v-notched cracks in dissimilar materials. The logarithmic stress singularity was discussed a little in Bogy's paper. The power-logarithmic stress singularity was reported by Dempsey and Sinclair. It was indicated that the logarithmic singularity is only a special case of power-logarithmic stress singularities. Then, Dempsey reported specific cases which have power-logarithmic singularities even fur homogeneous boundary conditions. It was known that logarithmic stress singularities for v-notched cracks in dissimilar materials occurs when the surfaces of a v-notched crack have constant tractions. In this paper, using the complex potential method, the stresses and displacements having logarithmic stress singularities were obtained and the coefficients vectors were calculated by a numerical program code: Mathematica. It was shown that our analysis models don't have logarithmic stress singularities under the constant tractions, although the coefficient vectors are existing.

• 대한기계학회논문집A
• /
• 제22권3호
• /
• pp.680-683
• /
• 1998

In case of the infinite body containing a rigid inclusion with line crack shape, stress intensity factor is determined and the relation between stress intensity factor and stress distribution near a crack tip is developed. Also, the relation between stress intensity factor and Kolosoff stress function is developed. Finally, these results are compared with those that the crack surface is under no traction.

• Journal of Korean Biological Nursing Science
• /
• 제25권2호
• /
• pp.123-130
• /
• 2023

Purpose: Sitting time, smoking, and perceived stress strongly influence physical health independent of physical activity. However, the associations among perceived stress, sedentary behavior, and smoking are poorly understood. Therefore, we examined the relationships between sitting time, smoking, and perceived stress in Korean adults aged < 65 years. Methods: We analyzed data from the seventh National Health and Nutrition Survey. In this cross-sectional study, data from 6,890 Korean adults aged < 65 years were analyzed. Complex-sample logistic regression was used to examine the relationships between sitting time, smoking, and perceived stress. Results: The group with a high sitting time (≥ 8 h/day) and those who smoked had significantly higher odds of experiencing stress than the low sitting time (< 8 h/ day) and non-smoking groups (odds ratio: 1.88, 95% confidence interval: 1.42-2.50). Conclusion: Perceived stress was positively correlated with current smoking status and increased sitting time. High sitting time (≥ 8 h/day) and current smoking were associated with a higher risk of perceived stress in Korean adults aged < 65 years.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2009년도 추계학술대회 논문집
• /
• pp.57-58
• /
• 2009

• 한국융합학회논문지
• /
• 제9권12호
• /
• pp.331-336
• /
• 2018

본 연구는 평소 자신의 업무에 대하여 지각하는 스트레스 지수가 높은 30~40대 직장 여성 50명을 대상으로 미용대체 요법이 스트레스 완화에 미치는 복합적인 영향을 분석하여 급변하는 현대사회에서 여성 직장인들이 받는 스트레스를 완화시켜 건강하고 아름다운 삶을 유지하는데 도움을 주고자 하였다. 미용요법은 향기요법과 건식 이완 마사지를 15분간 시행하였으며, 시행 전 설문을 통하여 스트레스 지수를 확인하였다. 실험은 주1회 4주간 시행되었고 결과 측정은 타액 내 코티졸의 농도로 분석하였다. 그 결과 실험 전 스트레스 지수 평균은 3.97로 높게 나타났으며, 실험 후 대상자들의 코티졸 농도는 유의하게(p<0.05) 낮아졌고 특히, 기혼과 부양책임을 가진 대상자들에게서 더 많은 변화를 보였다. 이상의 결과로 향을 이용한 건식이완 마사지는 스트레스가 심한 30~40대 여성들의 심신 안정에 매우 효과적인 것으로 판단되며 이러한 미용적 방안을 잘 적용한다면 스트레스 관리에 도움이 될 것으로 판단된다.

• 대한기계학회논문집
• /
• 제12권2호
• /
• pp.286-294
• /
• 1988

본 논문에서는 Bogdanoff가 제시한 열응력 관계식을 이용하여 균일 열유동을 받는 무한체내에 존재하는 균열에 대해서 균열표면에 자유트랙션조건과 열경계 조건을 부여하여 TSIF를 구하고자 한다. 다루고자 하는 커스프 균열의 형태는 하이포사이클로이드형(hypocycloid type), 대칭익형(symmetric airfoil type), 그리고 대칭입술형(symmetric lip type)이다.

• 동의신경정신과학회지
• /
• 제29권1호
• /
• pp.57-68
• /
• 2018

Objectives: To experimentally assess the anti-depressant effects of Gammakdaejo-tang Complex Extracts (GMDJ-Tang) in rats. Methods: Twenty Wistar Hannover (160~170 g) stressed rats were treated with different concentrations of GMDJ-Tang extracts i.e., 0, 62.5 mg/kg, 125 mg/kg, and 250 mg/kg. Chronic mild stress was induced by food deprivation, empty bottles, forced swimming, flickered light, tilt cages, shaking cages, high density breeding, water deprivation, and by soaking the litter cover according to fixed schedule. Blood and brain tissue samples were collected for biochemical analysis. Tests included serotonin and ELISA assays. Results: GMDJ-tang increased the weight of treated rats as well as levels of serotonin, BDNF and TrkB; however, the differences were not significant. In contrast, the extracts significantly decreased blood glucose in stressed rats. GMDJ-tang extracts did not significantly impact Serum AST, ALT, leukocytes, erythrocytes and thrombocytes when comparing treatment groups to control rats. Likewise, hemoglobin, hematocrit and PLT increased in treatment groups following treatment with GMDJ-tang, but this change was without significance. Conclusions: These results suggest that GMDJ-tang can alleviate chronic mild stress in rats, possibly through anti-depressant activity.

• Composites Research
• /
• 제13권4호
• /
• pp.67-74
• /
• 2000

계면크랙으로부터 먼 거리에 일정한 반평면(anti-plane) 전단력이 가해지는 경우에 대해서 복소변수 변위함수(complex variable displacement function)를 이용하여 곡면형상의 접합면을 가지는 폼과 복합재료의 접합재료에 대한 일반해를 고찰하였다. 점탄성 모델을 표현하기 위하여 Kelvin-Maxwell 모델을 제시하였으며, 폼의 점탄성을 나타내는 수학적 모델을 라플라스 변환을 이용하여 처리하였다. 폼의 점탄성 및 복합재료의 이방성을 고려하여 계면크랙에서의 응력세기계수를 예측하였다. 응력세기계수는 접합면의 곡률이 증가할수록 증가하는 경향을 보이며 시간이 지남에 따라 증가하다 일정값에 수렴하였다. 또한 폼과 복합재료 사이의 전단 강성계수비가 증가할수록 응력세기계수가 증가하였으며, 복합재료의 섬유방향이 응력세기계수의 변화에 미치는 영향은 점차 감소하였다.