• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.5
• /
• pp.505-511
• /
• 2014

The EPDM(ethylene-propylene diene monomer) rubbers used for manufacturing engine radiator hoses can be degraded by locally generated electrical stress in addition to thermal and mechanical stresses. This study presents an accelerated life prediction of the EPDM rubber under electrochemical stresses using the Arrhenius formula under various aging temperatures($60^{\circ}C$, $80^{\circ}C$, and $100^{\circ}C$). The modified life prediction formula considers the relationship between the gradient($E_a/R$) and the Arrhenius constant(C). The effects of tensile strain(5%, 10%) on the life of these rubbers were investigated. The aging temperature influences EPDM rubber life, and tensile strain was predicted. It was confirmed that the modified life prediction was within the data deviation level of the test.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.6 no.3
• /
• pp.151-158
• /
• 2002

Recently, the externally prestressed unbonded steel I-beam bridges have been increasingly built. The mechanical behavior of prestressed steel I-beams which are with external unbonded tendon is different from that of normal bonded PSC beams in a point of that the slip of tendons at deviators and the change of tendon eccentricity occurs, when external loads are applied in external unbonded steel I-beams. The concept of prestressing steel structures has not been widely considered, in spite of long and successful history of prestressing concrete members. In this study, The field experiment on prestressed steel I-beams has been performed in the various aspects of prestressed I-beam including the tend on type and profile.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.26 no.11
• /
• pp.1672-1681
• /
• 2002

To evaluate the thermal environments and the workload of farmers in the rice field in summer, this study investigated rice farmers' physiological, psychological responses, work postures, work clothes, air temperature and air humidity during the spraying pesticide in the rice field. Five career farmers (3 males, 2 females) volunteered as the subjects. During the spraying pesticide in the rice field, physiological responses were monitored continuously. The results were as follows. l. Farmers wore only raincoats not pesticide-proof clothing. 2. The value of WBGT, rectal temperature($T_{re}$), mean skin temperature(${\={T}}_{sk}$) were $24.9∼28.9^{\circ}C,\;37.8({\pm}0.3)^{\circ}C\;and\;33.6({\pm}0.6)^{\circ}C$, respectively. Clothing microclimate temperature($T_{cl}$) on the chest and back were $32.5({\pm}2.6)^{\circ}C\;and\;33.6({\pm}2.6)^{\circ}C$, respectively(p<0.00l). Humidity inside of the clothing ($H_{cl}$) was over 80%RH and heart rate(HR) was 112(${\pm}27$)bpm. We evaluated that the spraying pesticide was 'heavy work' by the Tre and HR. To four subjective questionnaires, all farmers expressed 'hard, hot, humid and uncomfortable' without individual difference at the end of works. We suggested that 1) the spraying pesticide in the rice field was a heavy work, 2) because the workload of farmers in the raincoat/pesticide-proof clothing can't be evaluated by only WBGT, assessors should measure physiological, psychological responses as well as thermal environments, 3) to alleviate farmers' heat strain, clothing manufacturers must consider not only the improvement of textile materials and clothing weight but also the designing of personal cooling equipment.

• Herbal Formula Science
• /
• v.10 no.2
• /
• pp.97-112
• /
• 2002

In order to investigate the effect of Sagoonja-Tang, Samool-Tang and Yookmijihwang-Tang against the cold, heat and immobilization stress, each formula was injected intragastically to mice exposed to forced cold water swimming($4^{\circ}C$), forced hot water swimming($42^{\circ}C$) and immobilization stress before measuring the change of plasma corticosterone level of mice. The results were as follows: 1. One hour after each Sagoonja-Tang, Samool-Tang, Yookmijihwang-Tang with the dose of 1g／kg, 3g／kg each were administered to mice, we put cold stress($4^{\circ}C$) on mice for 3min. Then those prescriptions didn't show any significant effect on plasma corticosterone level. however, Yookmijihwang-Tang(1g/kg) showed a significant increase(p〈0.05), and Samool-Tang(3g/kg) showed a small increase. 2. One hour after Samool-Tang, Sagoonja-Tang and Yookmijihwang-Tang with the dose of 1g／kg, 3g／kg each were administerd, mice exposed to heat stress($42^{\circ}C$) for 3 min. Samool-Tang(1g/kg) and Yookmijihwang-Tang(lg/kg) showed significant decrease of corticosterone level(p〈0.01, p〈0.05) but Sagoonja-Tang didn't change it. In the case of the dose of 3g/kg, only Samool-Tang decreased corticosterone level(P〈0.01), but Sagoonja-Tang, Yookmijihwang-Tang didn't make significant effect on plasma corticosterone level of the mice exposed to heat stress($42^{\circ}C$ ). 3. Those mice which exposed to immobilization stress one hour after Sagoonja-Tang, Samool-Tang, Yookmijihwang-Tang with the dose of 1g/kg and 3g/kg didn't show effective decrease of corticosterone level. However, Sagoonja-Tang(3g/kg), Samool-Tang(lg/kg, 3g/kg) showed the effect of mild increase of corticosterone level rather than decrease. These data revealed that the effect-variation of prescriptions depended on the kinds of stress and the dose of prescriptions had a different effect on therapy.

• Journal of Sasang Constitutional Medicine
• /
• v.18 no.3
• /
• pp.185-194
• /
• 2006

1. Objecrives Although Lee Je-Ma emphasized it is important to be aware of our own Nature & Emotion(性情) and control them properly, there is few case report about Taeyangin focused on their psychological sides. This report is about a Taeyangin patient who had Hae Yuk and Yul Gyuk syndrome caused by her stress from the work place and relationship with her seniors 2. Methods We observed the female patient had hospitalized in the Oriental Hospital of Dongguk University more than twice has been followed up for the last one year. We prescripted Mi-hoo-teung-shik-chang Tang as her physical symptom. The improvement of her physical conditions were checked through her sleep, meal, menstruation, stool and urine. And MMPI has been tested three times for the last one year to analyze her psychological progress. 3. Results and Conclusions Working in a group can cause hard stress for Taeyangin who is not good at adjusting themselves to whatever environment they are in. Mi-hoo-teung-shik-chang Tang could improve Taeyangin's physical conditions such as Hae Yuk, Yul Gyuk, insomnia, nausea, anorexia and hypouresis. But as her psychological aspect, she was getting more anxious, depressed and avoiding contact with others due to the stress. It is necessary to rake care of patients' psychological sides as well as physical conditions through managing their Nature & Emotion(性情).

• Journal of Applied Biological Chemistry
• /
• v.59 no.4
• /
• pp.361-364
• /
• 2016

We developed a spectrophotometric assay method for polyethoxylated ascorbic acidusing 3-ethyl ascorbic acid as standard material. The analytical method was validated by linearity, accuracy, precision, and stability. The coefficient of variation of the precision of the assay was less than 3.4 %. The linearity of the calibration curves in the desired concentration range is good ($r^2$>0.998). 3-Ethyl ascorbic acid and polyethoxylated ascorbic acid were stable in stock solution at room temperature for up to at least 6 h. The developed assay could be used for the content analysis of polyethoxylated ascorbic acid in samples.

• The Journal of the Korea Contents Association
• /
• v.18 no.6
• /
• pp.1-26
• /
• 2018

This study examines 17 ex-offenders' wives who is receiving housing support from the Korea Rehabilitation Agency to understood the difficulties child-rearing experiences with the grounded theory. Based upon the research outcomes, supporting that needs for prisoners' wives who feel a huge burden on taking care of infants and preschool children by themselves was discussed. The prisoners' wives with children at school age and initial/middle adolescent need to get strong support due to not only the shock about husbands in prison but also the burden and stress that should follow the role as parents of students. Those late adolescent/adulthood who were supposed to follow their dreams, were required for their financial and emotional sacrifice. Result indicates children need to get support to form the right identity, not to get exhausted or shrink from being stigmatized and prejudiced as children of released prisoners.

• Environmental Analysis Health and Toxicology
• /
• v.20 no.1
• /
• pp.67-73
• /
• 2005

오염물질의 노출에 의해 발현이 변화되는 유전자의 발굴은 외부환경 자극에 대한 적응이나 반응의 메커니즘을 알아내는뎨 중요한 정보를 제공하며, 오염물질에 반응하는 유전자는 환경오염을 감지하는 분자 마커로 개발될 수 있다. DD-PCR 기법은 차등 발현 유전자들을 발굴해내기 위한 유용한 방법으로 사용되어 왔고, 본 연구는 이 방법을 이용하여 벤조피렌에 반응하는 조피볼락 유전자들의 발굴을 목적으로 진행되었다. 간조직에서 추출한 RNA로부터 벤조피렌의 노출에 의해 발현 양이 달라진 12개의 클론을 발굴하였고, 그 염기서 열을 분석하였다. 또한 벤조피렌의 노출시간을 각각 6, 12, 24시간으로 달리한 조피볼락에서 12개의 클론 중 4개의 클론에 대해 northern blot 분석이 실시되었으며, 이들 모두 노출시간에 따 라 발현양이 증가 또는 감소하는 것이 확인되었다. 본 연구결과는 오염물질의 영향에 의한 유전자들의 발현에 관한 전반적인 지식을 제공하였고, 나아가 환경오염이나 외부 스트레스를 감지해 낼 수 있는 바이오마커의 개발을 위한 첫 단계로서의 정보를 제공할 수 있을 것으로 생각된다.

• Korean Journal of Plant Resources
• /
• v.30 no.1
• /
• pp.88-95
• /
• 2017

Effects of different soil water conditions on fruit characteristics were investigated in 5-year-old 'Nero' black chokeberry trees (Aronia melanocarpa). Three kinds of drought stresses, including low water deficit, severe water deficit, and very severe water deficit, due to decline of soil water decreased the fruit quality of weight of 10 berries, soluble solid content, and anthocyanin, compared with the control (consistent water supply) during the harvest period. After longer drought stress, supply of soil water could induce berry cracking because cell size of epidermis of fruits contracted, whereas cell size of sub-epidermis and flesh expanded. Thus periodic water supply using water supply facility is needed for yield and quality of 'Nero' black chokeberry fruits.

• Fashion & Textile Research Journal
• /
• v.8 no.3
• /
• pp.349-356
• /
• 2006

The purpose of this study was to compare the thermophysiological responses and subjective sensations of clothing materials with different water transfer property investigated in exercising and resting subjects at an ambient temperature of $20^{\circ}C$ and a relative humidity of 40%. Two kinds of clothing ensemble were tested: 100% cotton with highly water-absorbent but slowly dry properties(C) and 100% polyester with quickly water-absorbent and dry properties by four capillary channels(QADP). Seven apparently healthy male participants each undertook two series of experiments comprised 10-min of rest, 20-min of exercise with 70% of $VO_{2max}$ on a treadmill and 20-min of recovery. Mean skin temperature was significantly lower in QADP than in C during exercise and recovery. Clothing microclimate temperature was significantly lower in QADP during exercise and clothing surface temperature was also lower in QADP especially during recovery. Also, clothing surface humidity was significantly higher in QADP after the later half of exercise. The concentration of blood lactic acid tended to decrease to a lower level at recovery 3 minutes when wearing QADP rather than C clothing ensemble. Metabolic energy was marginally significantly less during the second half of exercise in QADP. Body mass loss tended to be greater in C than in QADP. The participants had better scores in thermal sensation, comfortable sensation and wetness in QADP during exercise and recovery. These results show that functional materials with quickly water-absorbent and dry properties can alleviate heat strain and induce more comfortable clothing microclimates and subjective sensations in the exercise-induced hyperthermia.