• 한국기계가공학회지
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• 제10권6호
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• pp.152-158
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• 2011

An electric upsetting process by the rigid-thermoviscoplastic finite element method was simulated in this study. Several engineering assumptions were made to calculate the heat generation due to the electric resistance. The skin effect of the bar was taken into account for the heat generation. The approach was applied to simulate an artifical electric upsetting process for the exhaust valve of the ship engine.

• Journal of Computational Design and Engineering
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• 제3권4호
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• pp.349-362
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• 2016

The numerical solutions of unsteady hydromagnetic natural convection Couette flow of a viscous, incompressible and electrically conducting fluid between the two vertical parallel plates in the presence of thermal radiation, thermal diffusion and diffusion thermo are obtained here. The fundamental dimensionless governing coupled linear partial differential equations for impulsive movement and uniformly accelerated movement of the plate were solved by an efficient Finite Element Method. Computations were performed for a wide range of the governing flow parameters, viz., Thermal diffusion (Soret) and Diffusion thermo (Dufour) parameters, Magnetic field parameter, Prandtl number, Thermal radiation and Schmidt number. The effects of these flow parameters on the velocity (u), temperature (${\theta}$) and Concentration (${\phi}$) are shown graphically. Also the effects of these pertinent parameters on the skin-friction, the rate of heat and mass transfer are obtained and discussed numerically through tabular forms. These are in good agreement with earlier reported studies. Analysis indicates that the fluid velocity is an increasing function of Grashof numbers for heat and mass transfer, Soret and Dufour numbers whereas the Magnetic parameter, Thermal radiation parameter, Prandtl number and Schmidt number lead to reduction of the velocity profiles. Also, it is noticed that the rate of heat transfer coefficient and temperature profiles increase with decrease in the thermal radiation parameter and Prandtl number, whereas the reverse effect is observed with increase of Dufour number. Further, the concentration profiles increase with increase in the Soret number whereas reverse effect is seen by increasing the values of the Schmidt number.

• 한국화재소방학회논문지
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• 제30권3호
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• pp.16-22
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• 2016

소방공무원의 화상방지를 위해 소방보호복의 개발이 이루어지고 있으나, 보호 성능을 높이기 위해서 소재의 두께가 증가하고, 그럼으로 경량화 달성이 어려워지는 단점이 존재한다. 이를 극복하기 위한 여러 가지 방법 중 Phase Change Material(PCM, 상변화 물질)을 적용한 섬유를 소방보호복 안감에 적용하는 연구가 진행되고 있다. 기존 연구의 경우, 고온노출시 PCM 적용 섬유의 온도 특성에 대한 연구가 일부 있었으나, 화상 발생과의 직접적인 연관성을 살펴볼 수가 없다는 큰 단점이 존재한다. 본 연구에서는 짧은 시간 고열유속 상태의 돌발화염조건에 대해 현재 사용되고 있는 소방보호복 안감에 대한 PCM 적용 여부에 따라 2도 화상 발생 억제 효과를 수치계산을 통해 살펴보았다. 피부의 화상 해석을 위해 생체 열전달 방정식(Bio-heat transfer)을 이용하여 지배방정식을 유도하였으며, 유한차분법(Finite Difference Method)을 활용하여 화상에 대한 예측을 수행하는 수치해석 접근법을 사용하였다. 시간에 따른 온도 및 손상함수 결과 분석을 통해 PCM 소재의 열흡수가 열전달을 지연시키는 효과가 큼을 확인할 수 있었고, 그에 의해 화상발생을 방지하는 매우 유효한 방법임을 확인할 수 있었다.

• 대한한방소아과학회지
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• 제30권2호
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• pp.1-9
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• 2016

Objectives Hataedock is a Korean herbal medical oral treatment that removes fetal toxic heat and meconium from new born babies. The purpose of this study is to evaluate whether Hataedock treatment of Duchi extracts has anti-inflammation effects on AD (Atopic Dermatitis)-induced NC/Nga mice. Methods After Hataedock treatment of Duchi extracts on days 0, 3-week-old NC/Nga mice were sensitized on days 28, 35, 42 by exposure of DNFB (dinitrochlorobenzene) and were induced to have AD. Immunohistochemistry of NF-${\kappa}B$ p65, iNOS, COX-2 and TUNEL assay of apoptotic body was used to identify changes of skin damages and anti-inflammation effects. Results The alleviate effect of the skin damage and angiogenesis was observed in DT group. The damage of stratum corneum, hyperplasia, edema, infiltration of lymphocytes and distribution of capillary were decreased in DT group. Also, the study results suggested that Hataedock treatment of Duchi extracts in DT group remarkably downregulated levels of NF-${\kappa}B$ p65 by 70% (p < 0.001), as well as COX-2 by 51%, iNOS by 62% (p < 0.001). Additionally, Hataedock treatment of Duchi extracts in DT group up-regulated apoptosis of inflammatory cells by 68% in atopic dermatitis-like skin lesion. Conclusions From the study results, we observed that Hataedock treatment of Duchi extracts alleviates AD through diminishing various inflammatory cytokines in the skin lesions, which are involved in the initial steps of AD development. It is anticipated to have potential applications for prevention and treatment of atopic dermatitis.

• The Korean Journal of Physiology
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• 제23권1호
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• pp.139-149
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• 1989

Although tail flick reflex (TFR) in rats has been used as a classic model of the nociceptive test to evaluate the action of analgesics, there have been few studies on the origin of the latent period of TFR. Present study was performed to elucidate the mechanism of increase in latency of TFR by morphine in anesthetized rats. Tail skin and dorsolateral tail nerve were stimulated electrically and EMG activities were recorded from abductor caudae dorsalis muscle participating in tail flick reflex. In the case of noxious radiant heat stimulation to tail, the tail flick tension was recorded before and after administration of morphine. Then changes in latency and conduction velocity of peripheral nerve were evaluated. The results obtained were as follows: 1) The latencies of TFR evoked by the electrical stimulation of tail skin and dorsolateral tail nerve were all within 40 ms and were elongated by several milliseconds from control after the administration of morphine. Peripheral conduction velocities of tail flick afferent nerve were within the range of 10-25 m/s. 2) The conduction velocity of peripheral nerve was significantly reduced after morphine administration, therefore the afferent time (utilization time+conduction time to spinal cord) was significantly increased. But the time for central delay and efferent time was not affected by morphine. 3) The conduction velocity under room temperature $(20-25^{\circ}C)$ was significantly reduced after morphine while that under vasodilation state $(40{\sim}42^{\circ}C)$ increased, 30 min and 45 min after morphine. The conduction velocity under vasodilation state without treatment of morphine increased continuously 4) The latency in tension response of TFR evoked by electrical stimulation was elongated by several milliseconds from control while the latency evoked by noxious radiant heat was elongated by several seconds compared with that of control. From the above results, it could be concluded that: 1) the increased latency of TFR evoked by electrical stimulation of the tail after morphine administration was due to the reducton in conduction velocity of peripheral nerve, which was the secondry effect of morphine on the peripheral vasomotion and 2) increased latency of TFR evoked by noxious radiant heat was also due to the same effect of morphine and the increase in cutaneous insulation to the noxious heat.

• 한국환경보건학회지
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• 제33권3호
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• pp.211-216
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• 2007

This study was to determine the effect of cooling part of the trunk without harm for the health. The results provide basic data for the development of clothing which could increase work efficiency and reduce body strain in hot environment. Eight males took part in the study. The experiment was conducted in a climate-chamber controlled with $37{\pm}1^{\circ}C,\;50{\pm}5%R.H$. The trunk was divided into six areas to be cooled: head, neck, chest, abdomen, the upper back, the lower back. According to preceding studies, permissible safety cooling limits of skin temperature, of each part of the trunk for four hours cooling were $25^{\circ}C$ on the head, $20^{\circ}C$ on the neck, $27^{\circ}C$ on the chest, $25^{\circ}C$ on the abdomen, $20^{\circ}C$ on the upper back, $20^{\circ}C$ on the lower back. So cooling temperatures of each region set up temperatures above mentioned. In conclusion, the head, the neck and the upper back cooling could reduce sweating amount, rectal temperature and heart rates and reduce the heat stress of workers exposing in the hot environment by decreased subjective sensations of heat and comfort. Thus, it was concluded that effectiveness of cooling among the trunk was best on the head and the neck.

• 대한화장품학회지
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• 제41권1호
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• pp.27-34
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• 2015

나노입자의 응용은 1970년대부터 발전되어 왔다. 금속 나노입자에 빛을 조사하면 나노입자 표면에서 플라즈몬 공명(SPR, surface plasmon resonance)을 일으킨다. SPR 효과는 금속표면에 입사한 빛에너지에 의해 전자가 여기하며 공명을 일으켜 진동을 발생시키는 현상을 말한다. 여기 된 전자들이 금속원자들과 충돌을 일으키며 열에너지로 전환될 수 있는데 이를 금속의 광열효과(photothermal effect)라고 한다. 우리는 광열 효과를 이용하여 온열 화장품의 개발 가능성을 제시하고자 한다. 온열 화장품의 개발을 위해 생체 독성이 적은 금 나노입자를 선택하여 광열 효과에 있어서의 세포 생체적합성과 열효율을 살펴보았다. 금 나노입자의 합성 상태는 금 나노입자가 갖는 독특한 흡광 스펙트럼으로 확인하였으며, 금 나노입자의 농도는 원자 흡광분석기로 측정하였다. 세포의 독성평가는 MTT assay와 이중 염색법을 사용하였으며, 금 나노입자의 광열 효과는 제논 램프를 광원으로 하여 금 나노입자의 농도의 증가에 따른 광열 효과증대를 적외선-열화상 카메라로 확인하였다. 금 나노입자의 광열 효과를 온열 화장품에 적용한다면 한대 지방의 기후, 또는 겨울철에 태양 에너지를 열에너지로 전환시켜 피부에 손실된 열을 공급, 피부온도 유지에 도움이 되고 피부건강에 긍정적 효과를 주리라 사료된다.

• 대한화장품학회지
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• 제30권2호
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• pp.167-172
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• 2004

피부 활성 물질로 넓이 알려져 있는 vitamin C (L-Ascorbic acid)는 콜라겐 생합성 촉진과 강한 항산화 작용으로 피부 항노화 및 주름 개선 효과 있을 뿐만 아니라 멜라닌 세포 활성 억제, 자외선 차단, 상처치유 등의 효능을 갖고 있다. 그러나 물성 면에서 피부 자극과 수분 및 공기, 빛에 불안정하여 쉽게 산화된다는 단점을 갖고 있다 이러한 문제점을 해결하기 위해 많은 연구가 진행되어 왔고, 그 결과 다양한 vitamin C 유도체가 개발되었다. 그러나 아직까지도 vitamin C의 불안정한 물성을 해결하면서 그 자체의 효능을 피부에 적용시키기에는 미흡한 점이 많다는 평을 받고 있다. 본 연구에서는 이러한 vitamin C의 불안정한 물성을 개선시키고 그 효능을 피부에 적용시킬 수 있는 vitamin C 유도체를 개발하기 위해, 피부 친화성이 우수한 스핑고지질류 중 하나인 phytosphingosine을 이용하여 산염기 반응에 의한 vitamin C의 OH기와 phytosphingosine의 -NH$_2$이온 결합시킨 새로운 vitamin C 유도체인 phytosphingosine ascorbate (SP-VC)를 합성하였다. 이렇게 합성된 phytosphingosine ascorbate (SP-VE)는 원소 분석(C58.3 : H9.3 : N2.8 : 029.5) 및 mass spectrosocopy (Maldi TOF-MS), UV/vis spectra (268.5nm), $^1$H NMR, FT-IR, 열분석 (m.p=154$^{\circ}C$), HPLC 등을 통하여 구조 및 물성을 확인하였다 또한 효능면에서는 우선적으로 phytosphingosine ascorbate(SP-VC)의 항균 및 항산화 효과를 확인하였다. 이러한 결과를 토대로 vitamin C와 phytosphingosine의 효능을 동시에 갖으며 불안정한 물성과 자극을 개선시킬 것이라 예상되는 새로운 소재를 합성하였다.

• 한국의류학회지
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• 제36권4호
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• pp.371-381
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• 2012

This study investigates quantitative wear training effects and involved 15 participants from a previous study (part 1) in May to September 2009. Before wear training, the subjects' rectal temperature, skin temperature, heart rate, blood pressure and local sweating were measured for 1 hour in a climate chamber ($39{\pm}1^{\circ}C$, $65{\pm}5%RH$, 0.3m/s) to evaluate heat tolerance. Subsequently, the subjects were divided into 3 groups that consisted of 5 participants. Group N (control-group) dressed the participants so that they felt comfortable (or cool). Group W and MW where participants underwent regular wear training for 10 weeks (5 days a week a total of 50 times). The intensity of the wear training for the participants of group MW was stronger than that for group W. A heat-tolerance experiment was performed after wear training. The results were as follows: 1. The participants of groups W and MW felt more comfortable after wear training than before wear training in the case of warmer $T_{cl}$. However, no significant differences were observed before and after wear training for group N. 2. The heat tolerance of the participants of groups W and MW was higher after wear training than before wear training. However, no significant difference was noted in this regard for group N. 3. The results showed the wear training effect (based on quantitative guidelines). The results show that the predicted optimal temperature inside clothing can enhance heat tolerance.

• 대한화장품학회지
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• 제23권3호
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• pp.128-133
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• 1997

In manufacturing emulsion lipstick in the past, heat and emulsifyoil phase made with oil, wax and lipophilic emulsifier with water phase together; and then mold above-mentioned materials, so-called lipophilic emulsified lipstick production method has been used. However it is hard to manufacture products using the above said method and furthermore, weak in moisturizing effect, lip care and stability. In this paper, I will discuss about multi-emulsion lipstick complementing already existing emulsion lipstick in terms of stability, giving moisturing effect of lip, and outstanding protection effectiveness of skin by safely gelatinating the state between amphiphilic lipid and water in stable.