• 대한금속재료학회지
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• 제49권6호
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• pp.462-467
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• 2011

In order to understand why annealing at $480^{\circ}C$ for several hour prevents the initiation of PWSCC, the residual stress variation with isothermal annealing at $480^{\circ}C$ and isochronal annealing between 480 and $800^{\circ}C$ in cold rolled Alloy 600 was investigated by the XRD method. The isothermal annealing decreased residual stress slightly in the rolling direction but not in the transverse direction, whereas the isochronal annealing for two hours increased residual stress. It seemed that the decrease in residual stress by isothermal annealing was due to lattice contraction by an ordering reaction because the isothermal annealing increased hardness. The effects of the isochronal annealing could be interpreted as the influence of thermal expansion and a disordering reaction.

• 한국도시철도학회논문집
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• 제6권4호
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• pp.383-392
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• 2018

본 연구에서는 비교적 경간이 긴 트러스교를 포함한 무도상 교량을 대상으로 장대레일을 부설할 때 궤도-교량 상호작용으로 인한 레일 부가 축응력과 교량 지점 반력 등의 변화를 검토하여 레일 장대화를 위한 개량 방안을 분석하였다. 연구결과에 따르면 무도상 교량에서 장대레일을 부설할 경우 레일 부가 축응력과 지점 반력이 큰 폭으로 증가하는 것으로 나타났다. 레일 부가 축응력은 횡저항력을 충분히 확보할 경우 수용 가능하지만, 지점 반력이 증가하게 될 경우 받침이나 교각의 손상이 우려되고 대규모 보수 보강을 필요로 하므로 지점 반력을 완화시킬 수 있는 방안을 강구할 필요가 있다. 교량 가동단의 마찰저항을 고려하는 경우 레일 부가 축응력은 감소하지만 지점 반력에 미치는 영향은 매우 작은 것으로 나타났다. 반면 궤도 종저항력이 작아지면 레일 부가 축응력과 지점 반력이 모두 큰 폭으로 감소하는 것으로 나타났으며, 레일 부가 축응력이 큰 일부 구간에 ZLR 체결장치를 적용하는 경우 레일 부가 축응력 뿐 아니라 교량 지점 반력이 크게 감소하는 것으로 나타났다. 따라서 무도상 교량의 레일 장대화를 위하여 일부 ZLR 체결장치를 적용하고 궤도 종저항력을 줄이는 방안이 매우 효과적이라고 판단된다.

• 여성건강간호학회지
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• 제9권3호
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• pp.224-234
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• 2003

Purpose: This study was to test the effects of a full body massage on labor pain and delivery stress reaction for primipara during labor. Method: This study employed a quasi- experimental method(nonequivalent control group, pre-post test design). The subjects of this study were 57 primipara hospitalized at the U OB & GYN hospital in Inchon from November 1. 2001 to July 31, 2002. 28 women were assigned to the experimental group and 29 to the control group. The experimental group was given 20 minutes full body massage for each of three delivery phases. The control group was given conventional delivery care. The levels of labor pain were measured by the Visual Analogue Scale and the expression scores of the labor pain and the levels of delivery stress reaction were measured by pulse rate, respiration rate, and blood pressure, and State-Anxiety Scale. Data were analyzed using the repeated measures analysis of covariance(ANCOVA), t-test, $X^2$- test, simple ANCOVA with SPSS program. Result: There was no interaction effect between time and group(F=.370, p=.693), but significant time effects were found for subjective labor pain(F=3.840, p=.028). There was no interaction effect between time and group(F=.112, p=.894), but significant group effects were found for objective labor pain(F=12.299, p=.001). There was no interaction effect between time and group for PR(F=.172, p=.843), RR(F=.626, p=.539), SBP(F=.089, p=.915), DBP(F=.748, p=.479), but significant group effects were found for SBP(F=7.547, p=.008). The level of status anxiety of the experimental group was significantly lower than the control group(F=11.787, p=.001). Conclusion: This study showed that the full body massage has partially positive effect on labor pain and delivery stress reaction. Therefore this study suggested that the full body massage might be used clinically to help primipara during labor.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제26권4호
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• pp.266-272
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• 2015

Objectives : This study examined the impact of peer's suicide on mental health of middle-school students. The aim of this study was to describe the course of posttraumatic stress and grief reaction, suicide ideation, and depression score among adolescents after exposure to peer's suicide and to examine the relationship between posttraumatic stress and other mental health scores in these subjects. Methods : Thirty seven middle school students who were exposed to the suicidal death of a peer completed self-report measures to assess levels of depression, grief reaction, post-traumatic stress, and suicide ideation at 1 month and 8 months after the peer's suicide. Results : There was no significant change in mental health scores between 1 month and 8 months. Level of posttraumatic stress after 8 months was related to acute grief response. Subjects who experienced a clinically significant level of suicidal ideation and posttraumatic stress showed more mental health problems. Conclusion : The results suggested that peer's suicide strongly impacted mental health issues of adolescents at a critical time of adolescent development. Clinicians should perform a thorough evaluation of mental health problems for youth who experienced peer's suicide and help them in management of their grief reaction.

• 환경위생공학
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• 제6권2호
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• pp.59-68
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• 1991

The word of stress was wsed in the field of physics as a external force from 17th century, but the meaning of this stress had chafed to the internal and exteral demand fort the human body in medical area. All the stumulants which make stress was called as j stressor. When animals get stress blucose excreted from liver to adapt for the emergent state ant some related hormone secrete convert protein and lipid to glucose for the purpose of energy supply to muscle. As a results heart rate, blood pressure, respiration rate are increased and musclse are strengthed. These physiolgical reactions ate controlled by autonomic nerve system under the control of hyothalamus in brain. Autonomic nerve system and endocrinary system are react harmoiously to stress reaction. According to the stress reaction, adrenomedullary system are stimulated, and epinephrine, morepinephrine are exceted. Author experimented the effect of the immobilizational stress to rat by analyzing the variaition of catecholamine secrction, the Na concentration and the effect of the antistresf effect by Panax Ginseng which is a traditional Korean herb medicine. The concentration of the norepinephrine, epinephrin, and dopamin in normal rat are 1 578 ng/ml, 0.365 ng/ml, and 0.731 ng/ml respectively, but in the immobilyzed stress groIn the concentration were increased to 1.915 ng.ml, 0.854 ng/ml, and 2,361 ng/ml which she the high show the higher concentration of catecholamine to stressor.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.1195-1201
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• 2002

Researches on the FRF-based substructuring method have been mainly focused on vibratory response analysis. Present study Is concerned about the application of the method to the dynamic stress analysis of a air-conditioner compressor mounting bracket in a passenger car. This is performed by using reaction forces that can be obtained by the FRF-based substructuring method. The air-conditioner system, composed of a compressor and bracket, Is analyzed by using the FRF-based substructuring method. The experimental and numerical FRFs are combined to calculate the system responses and reaction forces at the connection point. The dynamic reaction forces plugged into the bracket FE model to compute the stresses of the bracket Dynamic strains by the present method are compared with those from strain-gage test for bracket system on shaker. The comparison shows possibility of practical usage of the method for the real problem

• 한국해양공학회지
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• 제13권1호통권31호
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• pp.94-104
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• 1999

In order to evaluate the performance of axially of laterally loaded piles experimentaly, pile load tests can be carried out at the site Otherwise stress analyses or subgrade reaction analyses can solve the problem. In this study, stress analysis using FLAC code and subgrade reaction analyses using load transfer curves recommended by API(1993) were performed consistently on the basis of a result of site investigations, and the result of analyses was compared with the measured. As a result the behavior of pile heads was analyzed accurately for both axially and laterally loaded tests. Furthermore axially transferred loads were calculated appropriately for the measured and axial loads were transferred mainly mainly by the frictional resistance rather than by the tip resistance. Consequently, it can be commented that both analysis methods of soil-pile systems are applicable at teh objective site and that solutions may be more accurate if material properties from the site investigation are more explicit.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.513-516
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• 2001

Water stress measurements of rice that use spectral reflection characteristics have been conducted to detect a water stress of rice during growing stage. Water stress reaction was measured using a spectroradiometer in the wavelength range from 300nm to 1100nm. In order to maintain all the experimental conditions, the measurement time have been settled at a fixed solar radiation times. Spectral reflectance were measured as a function of the moisture content. The results indicate that the spectral reflectance of rice was dependent on moisture content. As the moisture content is lowered the spectral reflectance of rice formed in NIR wavelength range increased. This effect can be best explained in terms of water stress.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권2호
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• pp.45-50
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• 2005

To improve mean-life and reliability of power cable, in this study, we have investigated electrical properties and stress-strain showing by changing the content of carbon black that is semiconductive additives for underground power transmission. Specimens were made of sheet form with the nine of specimens for measurement. Volume resistivity of specimens was measured by volume resistivity meter after 10 minutes in the pre-heated oven of both 25±1 [℃] and 90±1 [℃]. And stress-strain of specimens was measured by TENSOMETER 2000. A speed of measurement was 200[mm/min], ranges of stress and strain were 400[Kgf/㎠] and 600[%]. In addition tests of stress-strain were progressed by aging specimens in air oven. From this experimental results, volume resistivity was high according to increasing the content of carbon black. And yield stress was increased, while strain was decreased according to increasing the content of carbon black. And stress-strain were decreased some after aging because of oxidation reaction of chemical defect. We could know EEA was excellent more than other specimens from above experimental results.

• 한국지반공학회논문집
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• 제18권6호
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• pp.33-42
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• 2002

지반 굴착시 지반의 변위특성과 지보재의 설치시기에 대한 중요한 정보를 제공하는 지반반응곡선(Ground reaction curve)을 구하는 방법은 일반적으로 원형단면이고 측압계수 K＝1.0인 상태를 가정한 closed from solution을 통해서 구해지지만, 실제 현장에서는 주로 마제형 굴착단면이 사용되며 $K\neq$1.0인 경우 대부분이다. 지반 굴착시 측압계수와 굴착 형상에 따라 측벽에서의 초기탄성변위 및 임계지보압이 변화하는 경향을 알아보기 위하여 측압계수 값을 0.5～3.0 사이에서 변화시키고, 각 측압계수마다 초기연직응력을 5～30MPa 사이에서 변화시켜가면서 원형단면과 마제형 단면인 경우를 구분하여 수치해석을 통해 지반반응곡선을 얻었다. Closed form solution에 의해 얻어진 지반반응곡선은 측압계수와 굴착단면의 형상을 고려하지 못하기 때문에 $K\neq$1.0인 실제 지반에 대한 변위거동과 지반의 자립성을 평가하는 데 큰 오차를 유발할 수 있는 것으로 나타났다. 따라서, Closed from solution에 의해 지보재의 설치시기를 예측하는 것은 많은 오차를 수반하는 과정이므로, 수치해석을 통한 지보설치 시기와 자립성에 대한 검토를 수행하는 것이 바람직 할 것으로 판단된다.