• Korean Journal of Food Science and Technology
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• v.25 no.3
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• pp.252-257
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• 1993

Nine Korean native cattle were purchased from a beef cattle farm. Immediatly after slaughtering and skinning, each carcass was split into left and right sides and the one half was kept as a control, the other one was electrically stimulated by using 400v stimulator for 1 min. All samples were analyzed for shear force value, ATP and biochemical changes to investigate the effect of electrical stimulation during storage at $5^{\circ}C\;and\;15^{\circ}C$. The amount of lactate of electrically stimulated (E.S.) meat showed a rapid increment compared with that of control (p<0.01). E.S. treatment caused a rapid drop of pH value. Initial pH decreased from 6.85 to 6.38 in M. semitendinosus and from 7.0 to 6.58 in Triceps brachii by E.S. treatment (p<0.01). Electrically stimulated muscle showed decrease (34.67%) in ATP to $5.74{\mu}mole/g$ from $8.78{\mu}mole/g$ of unstimulated meat. ATP of the electrically stimulated muscle stored at $15^{\circ}C$ and $5^{\circ}C$ was degraded faster than that of control until 6 hours post-mortem (p<0.05). The tenderness of meat after aging was improved significantly by electrical stimulation with lower shear force value than that of untreated meat (p<0.01).

• Particle and aerosol research
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• v.13 no.4
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• pp.151-158
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• 2017

Electrostatic precipitator is widely used to remove particulate matters in indoor air and industrial flue gas due to low pressure drop and high collection efficiency. However, it has a low collection efficiency for the submicrometer sized particles. Electrospraying is a potential method to increase the particle charging efficiency, which results in increased collection efficiency. Although particle charging efficiency is highly dependent upon droplet size, the effective measuring method of the droplets is still uncertain. Tap water was electrosprayed in this study, and the images of electrosprayed droplets were taken with a high speed camera coupled with several visualization methods in order to measure the droplets size. The droplet size distribution was determined by an image processing with an image-J program. As a result, a droplet measured by a laser visualization, had a half size of that by a Xenon light visualization. In addition, the experimentally measured droplet sizes were a good agreement with the predicted values suggested by $Fern{\acute{a}}ndez$ de la Mora and Loscertales(1994).

• Journal of Physiology & Pathology in Korean Medicine
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• v.32 no.6
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• pp.403-410
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• 2018

Lifestyle of adolescents cause a lot of health effects in the future. Therefore, in Korea, school health law was enacted and relevant business such as school education program is being carried out. This study was conducted to recognize symptom according to grade. A survey of youth health status was conducted at 19 middle and high schools in Seongnam city from May 2015 to December 2015. The survey made up of 14 questions which was about the health status satisfaction on the adolescent was conducted to investigate frequency by year and the respective health status of 6 grades. A total of 9,584 students responded to the survey, 58.22% answered that they were not free of constipation. 25.69% of respondents had no symptoms of headache, consequently over 70% of respondents had headache. 57.06% of respondents had no symptoms of low back pain and 34.7% had no symptoms of neck & shoulder pain, therefore over 50% of respondents had muscular skeletal symptoms. In menstrual history, only 17.95% of respondents said their period was regular and painless. In respiratory history, except cold, no nasal drop & obstruction has appeared in the group of 54.02%. And 62.97% of respondents had persistent cough usually with cold and 23.41% had cough with cold breeze even if not catch cold. In the third grade of high school students, there were many complaints of pain in various parts such as headache, back pain and shoulder pain, neck pain and menstrual pain, and there was a high rate of complaints of digestive system symptom and defecation symptom. More than half of respondent had constipation discomfort, headache and musculo-skeletal symptoms, menstrual problems and cough. In the third grade of high school students, the rate of complaints of pain complaints, digestive system symptoms, and bowel symptoms was high. Therefore, there is a need for measures and management for continuous health care and health promotion in accordance with students' symptoms and age at each grade level.

• Applied Chemistry for Engineering
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• v.22 no.1
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• pp.37-44
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• 2011

The critical micelle concentration (CMC) of sorbitan laurate SP 20 surfactant in this paper was near $7.216{\times}10^{-4}mol/L$ and the surface tension at CMC was about 26.0 mN/m, which showed higher CMC and lower surface tension than those of octylphenol ethoxylate octylphenol ethoxylate (OPE) 10 surfactant. Dynamic surface tension measurement using a maximum bubble pressure tensiometer showed that the adsorption rate at the interface between air and surfactant solution was found to be slower with SP 20 surfactant, presumably due to a low mobility of SP 20 surfactant monomer. The contact angle of SP 20 surfactant solution was observed to decrease with an increase in surfactant concentration and showed a larger value than that of OPE 10 surfactant solution. Half-life time for foams generated with 1 wt% surfactant solution was also larger with SP 20 surfactant, which indicated higher foam stability with SP 20 surfactant. Dynamic behavior study reveals that the solubilization of n-decane oil was much lower with SP 20, which is in good agreement with experimental results of foam stability, contact angle and CMC. Dynamic interfacial tension measurement by a spinning drop tensiometer shows that interfacial tensions at equilibrium condition in both systems were almost the same but the time required to reach equilibrium was longer with SP 20.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.645-668
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• 2022

Hydrogen energy is emerging as an important means of carbon neutrality in the various sectors including power, transportation, storage, and industrial processes. Fuel cell power plants are the fastest spreading in the hydrogen ecosystem and are one of the key power sources among means of implementing carbon neutrality in 2050. However, high volatility in system marginal price (SMP) and renewable energy certificate (REC) prices, which affect the profits of fuel cell power plants, delay the investment timing and deployment. This study applied the real option methodology to analyze how the dual uncertainties in both SMP and REC prices affect the investment trigger price level in the irreversible investment decision of fuel cell power plants. The analysis is summarized into the following three. First, under the current Renewable Portfolio Standard (RPS), dual price uncertainties passed on to plant owners has significantly increased the investment trigger price relative to one under the deterministic price case. Second, reducing the volatility of REC price by half of the current level caused a significant drop in investment trigger prices and its investment trigger price is similar to one caused by offering one additional REC multiplier. Third, investment trigger price based on gray hydrogen and green hydrogen were analyzed along with the existing byproduct hydrogen-based fuel cells, and in the case of gray hydrogen, economic feasibility were narrowed significantly with green hydrogen when carbon costs were applied. The results of this study suggest that the current RPS system works as an obstacle to the deployment of fuel cell power plants, and policy that provides more stable revenue to plants is needed to build a more cost-effective and stable hydrogen ecosystem.

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.1
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• pp.103-113
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• 1993

Every year, over $3.37{\times}10^7$ ton of municipal solid waste is generated in Korea, of which about 28% is organic food waste from restaurant, dining halls and households etc. Methane conversion of the food waste by anaerobic digestion could be a viable approach for energy recovery as well as safe disposal of the waste. However, as food waste is composed of highmolecular complex polymers such as cellulose, lignin and protein, anaerobic digestion of food waste has not been efficient in terms of volumetric loading rate, solid retention time and extent of anaerobic degradation. In this research, the improved anaerobic degradation of food waste was attemped by applying rumen microorganisms to anaerobic digestion. Acidification efficiency of food waste by rumen microorganisms was compared with that of conventional acidogenesis. And optimum acidification conditions by rumen microorganisms were also determined. For the experiments, anaerobic batch reactors of 600 mL was fed with the processed (dried and milled) food waste obtained from a restaurant. Ultimate volatile fatty acid (VFA) yield produced by rumen microorganisms was about 8.4 meq VFA/g volatile solid (VS) that is 95% of the theoretical value. This yield was not much different from that of conventional acidogenesis, but hydrolysis rate was about twice faster. Cumulative VFA concentration increased from 66 meq/L to 480 meq/L, when the initial TS was increased from 1% to 15%. But VFA yield at 15% TS was half of that at 1% TS. This inhibition on the acidification might be caused by the rapid drop of pH and higher concentration of nonionized VFA. Optimal pH and temperature range for the acidification were about 6.0~7.5 and $35{\sim}45^{\circ}C$, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.1 no.1
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• pp.73-82
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• 2000

Conventional funding system for the university research projects is limited to a grant or subsidy type funding method which does not require an obligation of refund. Such a funding system is known as ideal one for the university research activities which in general is not a profit oriented activities. It is considered ideal in a sense that nonprofit oriented research activities gives more emphasis on creativity than on efficiency or practical value. A venture- business-start-up research activity can not be considered as a pure nonprofit oriented activities. It clearly gives more emphasis on efficiency and practical value than on creativity Recently a large portion of the venture-business-start-up research activities are carried out in the universities. When a conventional research funding system is applied to such a new type of research activities, it turned out that the success rate is much lower than expectancy. This is why a new and differentiated funding system is sought for such a new type of research activities. A funding system of loan type for a venture-business-start-up research activities is proposed herewith. A loan system naturally requires a pay back after the successful start up of the venture business. This loan system nay be considered that a business concept is grafted on a conventional funding system for the university research activities. This means that a rather loose or generous terms and conditions of the money loan case is introduced into this funding system to remedy the short comings of the intrinsic nonprofit nature of the university research activities. The point is how to improve the success rate and how to reduce the undesirable aspect of the conventional university research activities when it is practiced with the new type of research activities. After one and half year of practicing with the new funding system. it can not be asserted that a definitely positive results could be obtained. but a trend of desirable aspects could be observed such as low drop out rate. project selection efficiency, higher sense of responsibility. etc.