• Composites Research
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• v.30 no.3
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• pp.181-187
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• 2017

The effect of nanoscopic and microscopic Fe, $Fe_3O_4$, and Ni particles and their shapes and substrate materials on the heating behavior of thermoplastic polyurethane (TPU) adhesive films was investigated via induction heating. The heat generation tendency of $Fe_3O_4$ particles was higher than that shown by Fe and Ni particles in the TPU adhesive films. When the Fe and Ni particle size was larger than the penetration skin depth, the initial heating rate and maximum temperature increased with an increase in the particle size. This is attributed to the eddy current heat loss. The heating behavior of the TPU films with Ni particles of different shapes was examined, and different hysteresis heat losses were observed depending on the particle shape. Consequently, the flake-shaped Ni particles showed the most favorable heat generation because of the largest hysteresis loss. The substrate materials also affected the heating behavior of the TPU adhesive films in an induction heating system, and the thermal conductivity of the substrate materials was determined to be the main factor affecting the heating behavior.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.4
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• pp.341-345
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• 2003

ZnWO$_4$shows excellent frequency selectivity due to its high quality factor(Q${\times}$f) at microwave frequencies. However, in order to use ZnWO$_4$as multilayered wireless communication components, its other properties such as sintering temperature(105$0^{\circ}C$). $$\tau$_f$(-70ppm/$^{\circ}C$) and $$\varepsilon$_r$(15.5) should be modified. In present study, TiO$_2$and LiF were used to improve the microwave dielectric and sintering properties of ZnWO$_4$. TiO$_2$ additions to ZnWO$_4$changed $\tau$$_{f}$ from negative to positive value, and also increased $$\varepsilon$_r$, due to its high $$\tau$_f$(＋400ppm$^{\circ}C$) and $$\varepsilon$_r$(100). At 20 mol% TiO$_2$ addition, $$\tau$_f$was controlled to near zero ppm/$^{\circ}C$ with $$\varepsilon$_r$=19.4 and Q${\times}$ f=50000GHz. However, the sintering temperature was 110$0^{\circ}C$. LiF addition to the ZnWO$_4$＋TiO$_2$ mixture greatly reduced the sintering temperature from 110$0^{\circ}C$ to 85$0^{\circ}C$ due to liquid phase formation. Also LiF addition decreased the $$\tau$_f$value due to its high negative $$\tau$_f$ value. Therefore, by controlling the TiO$_2$and LiF amount. temperature stable LTCC(Low Temperature Cofired Ceramics) material with low loss in the ZnWO$_4$-TiO$_2$-LiF system could be fabricated.d.d.

• Journal of Life Science
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• v.30 no.2
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• pp.202-210
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• 2020

As the elderly population increases, it is becoming important to prevent and treat muscle loss caused by aging or disease. Steroidal androgen in the protein assimilation steroid (AAS) system is mainly used to induce muscle improvement, but it is well known that long-term or excessive doses of AAS result in various side effects, although they are prescribed for various muscle and weight loss treatments. Research is therefore underway to explore natural substances that promote muscle renewal with relatively few side effects. However, despite many studies on the improvement of skeletal muscle and the reduction of muscle disease using natural products, there is still a lack of significant clinical results and mechanism studies. The promotion of muscle regeneration through treatment with natural substances typically involves three mechanisms: positive control of the muscle modulating factor (MRF), activation of the protein synthesis mechanism, and inhibition of the protein breakdown mechanism. A study of plant extracts that are known to have muscle neoplasmic stimulation effects, such as black ginseng, plum, and nutmeg, as well as single substances derived from natural products, such as creatine, catechin, and several fatty acids, is therefore described. We also summarize the mechanisms that have been identified so far through which each of these extracts or single materials facilitates muscle regeneration and the signaling pathways that they mediate.

• Korean Journal of Agricultural Science
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• v.17 no.1
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• pp.45-51
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• 1990

This study was conducted to obtain basic data for the design of cooling system by the test of engine performance of the power tiller being used widely in the rural area. Among the various factors affecting engine performance, the flow rate of cooling water was considered as the major factor in this study. Motoring loss, output, fuel consumption ratio, torque, heat absorption of cooling water, and thermal efficiency were measured and analyzed based on three flow rates of cooling water such as 15, 20, and $25{\ell}/min$. The results obtained were as follows : 1. Motoring loss of the engine was 1.371 kW at 2,200 rpm., and mechanical efficiency was 79.1% at rated output level. 2. Output power of the engine increased with the flow rate of cooling water increased. 3. BSFC was 282.9g/kW-h at the flow rate of $20{\ell}/min$, and the temperature of cooling water at outlet was $80.9^{\circ}C$. 4. There was a little variation of torque of the engine depending on the flow rate of cooling water. 5. Absorption of heat by cooling water was increased with the increase of flow rate. 6. The highest thermal efficiency of 32.3% at the flow rate of $20{\ell}/min$ was observed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.502-502
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• 2007

A catenary system should be designed to have an uniform elasticity over a span in order to maintain the lowest possible loss of contact between a pantograph and a contact wire. A elasticity uniformity of a catenary can be regarded as a important design factor used for predicting the current collection performance for a catenary. There are a couple of formulas to calculate the degree of elasticity uniformity of a catenary according to the literature survey. The effectiveness of these formulas is reviewed by performing catenary elasticity and loss of contact analysis for various different configurations of catenary systems using a beam element based FEM program. The results reveals that these formulas are not suitable to predict the current collection performance for a catenary. Therefore, a new formula based on the standard deviation of the elasticity over a span is proposed in this study. The analysis results show that the new formula for an elasticity uniformity of a catenary is very effective in predicting the current collection performance for a catenary.

• Journal of Korean Society of Disaster and Security
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• v.15 no.1
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• pp.47-56
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• 2022

Recently, water resources and energy policies such as integrated water management and carbon neutrality are changing rapidly. There is an opinion that the value of hydropower reservoirs related to these policies should be re-evaluated. In the past, they have contributed to flood control in addition to electricity generation, such as operating at a limited water level during the flood season, but loss of power generation is inevitable with this operation. Therefore, this study introduced the concept of resilience to the hydropower generation system to minimize the power loss. A framework for evaluating the power generation performance of them was presented by defining the maximization of electricity sales as performance. Based on the current procedure of multiple operation plan, a scenario was established and simulation was performed using HEC-5. As a result of applying to the framework, it was confirmed that the power generation performance according to each scenario was evaluated as an important factor. And it was confirmed that the performance of flood control and water use could also be evaluated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3197-3202
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• 2013

When car builder designs the large carbody structure of railway vehicles, it is necessary to optimize the damping characteristics through the analysis of structure borne noise such as sound pressure level(SPL). This paper is a study on the structure borne noise analysis by characterizing the damping of double skin aluminum extruded panels for rolling stock carbody. The normalized SPL was calculated based on the simple source theory using measured mechanical mobility parameters from vibration tests(i.e. point, transfer and modal mobility). The reduced SPL was predicted by using finite element method by applying loss factor of damping material into laminated shell elements. It was found out that the damping material coated on the panels like underframe, which part is seriously affected by vibration during train run, took effect to reduce noise level.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.6
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• pp.872-878
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• 2016

Astaxanthin (ASX) is a xanthophyll pigment isolated from crustaceans and salmonids. Owing to its powerful antioxidant activity, ASX has been reported to have the potential to protect against gastric ulcers and a variety of other illnesses. Histamine (His) is a dietary factor that causes gastric erosion and ulceration in young chicks. In this study, we examined whether ASX had protective effects on dietary histamine-induced lesions in the gizzard and proventriculus of broiler chickens. Four experimental treatment groups were planned: basal diet (BD), BD+His, BD+ASX, and BD+ASX+His, with four chicks (5 days old) in each group and three replications (i.e., a total of 12 chicks per group). The BD was supplemented with either 0.4% His or 100 ppm ASX. The birds were fed ad libitum for 3 weeks, and diets contained no antimicrobial compounds. Supplementing the diet with His significantly decreased body weight gain, but increased the weights of the gizzard and proventriculus of the chicks as compared with those of chicks in the BD group (p<0.05). ASX did not affect His-dependent changes in chick body weight or weights of the gizzard and proventriculus. The loss of gastric glands in the proventriculus, which was observed in His-treated chicks, was not prevented by ASX administration. The frequency of proventricular ulceration, however, was lowered by treatment with ASX, without significant differences between the two supplementation levels. In conclusion, our data showed that ASX might be helpful for alleviating structural damage to the digestive system in poultry under certain stressful conditions.

• Journal of Korean Academy of Nursing
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• v.25 no.4
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• pp.807-824
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• 1995

This study was intended to provide women who are experiencing menopause with effective nursing care by exploring the menopause experience. The purpose of the research was to understand the subjective feelings of women about the question of what the menopause experience is. Q-Methodological method was used for that purpose. As the research method, Q-statements were collected preliminary to the study of through in -depth interviews and a literature review. For the study 34 Q-statements were selected. There were 21 women as subjects for the research. The 21 women sorted the 34 statements using the principle of Forced Normal Distribution. The principle of Forced Normal Distribution, which has nine scales to measure the individual opinions, was called Q-Factor Analysis by using PC Quanl Program to supply the material. As a result, there were four categories(self-com-passion type, self-regulation type, self-perception type, self-abandonment type) of special opinion about the menopause experience in these women. The first type was called Self-compassion This type' was associated with varying degrees of emotonal instability(psychological withdrawal). And type in menopause signifies loss of a socially valued status and may result in depressive symptoms. This type expresses the menopause experience as associated with negative reaction. The second type is called Self-regulation. This type overcomes the menopause experience more actively than the other types and do not express the menopause experience as one of suffering. This type make efforts by themselves to regulate the mono-pause experience. The third type is called Self-perception. This type perceives the experience of menopause which as typical menopausal syndrome (hot flashes and decreased vaginal lubrication, decreased estrogen producing atrophic changes of the labia and vaginal mucosa, making intercourse uncomfortable). The fourth type is called Self- abandonment. This type denies the experience of menopause. The meaning of menopausal experience is significantly related with a life accident or life load. Also, This type experiences pain in the musculoskeletal system. As a result, The meaning of the menopausal experience is affected by perceived subjective experience of the nurses, the need to understand each persons meaning of the menopause experience and to develop appropriate nursing interventions based on the typology of menopause experience. Finally. The result of the study will provide basic data for nursing intervention the menopausal women.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.6
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• pp.1423-1430
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• 2008

The water extract of Sopung-tang(SPT) has been traditionally used for treatment of psycologic disease and brain damage in oriental medicine. However, little is known about the mechanism by which the water extract of SPT rescues cells from these disease. Therefore, this study was designed to investigate the effect of SPT on the glutamate-induced toxicity of rat C6 glial cells. SPT have protective effects in glutamate-induced toxicity, which was revealed as apoptosis characterized by chromatic condensation and fragmentation and the loss of mitochondrial membrane potential in C6 glial cells. Also, SPT have inhibited the active form of caspase-3 and PARP and significantly protected the apoptotic phenomena by glutamate toxicity in C6 glial cells. However, SPT significantly recovered the depletion of GSH and inhibited the generation of ROS by glutamate in C6 glial cells. In addition, both SPT and antioxidants such as GSH and NAC protected the glutamate-induced cytotoxicity in C6 glial cells, indicating that SPT possibly have antioxidative effect. Specially, SPT were showed transcriptional factor significantly increased the activation of NF-${\kappa}B$ using the analysis of NF-${\kappa}B$ luciferase reporter system in C6 glial cells. These NF-${\kappa}B$ activation protected cells from glutamate-induced toxicity to generate the heme oxygenase-1(HO-1). Taken together, we suggest that SPT have protective effects in glutamate-induced toxicity via a antioxidative mechanism.