• Journal of the Korean Society of Radiology
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• v.4 no.1
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• pp.5-9
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• 2010

In recent, a digital x-ray detector attracted worldwide attention and there are many studies to commercialize. There are two methods in digital x-ray detector. This method is an Indirect method and Direct method. This study is to see the differences between the digital x-ray detector based on a-Se used in the existing indirect conversion method and an x-ray conversion material that has better SNR(Signal-to-noise ratio) and property than the a-Se. To solve the problem that is difficult to make a large area film using Screen-Print method, we used a Screen-Print method. In this study, we used a polyclystal $HgI_2$ as x-ray conversion material and a sample thickness is $150{\mu}m$ and an area is $3cm{\times}3cm$. ITO(Indium-Tin-Oxide) electrode was used as top electrode using a Magnetron Sputtering System and each area is $3cm{\times}3cm$, $2cm{\times}2cm$ and $1cm{\times}1cm$ and then we evaluated darkcurrent, sensitivity and SNR of the $HgI_2$ film are measured, then we evaluated the electrical properties. And we used a current integration mode when I-V test. This experiment shows that the sensitivity increases in accordance with the area of the electrode but the SNR is decreased because of the high darkcurrent. Through fabricating of various thicknesses and optimal electrodes, we will optimize SNR in the future work.

• Korean Journal of Plant Tissue Culture
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• v.25 no.4
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• pp.257-261
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• 1998

The repeated subcultures of in vitro plant materials in wasabi became highly vitrified and the capacity for multiple shoot formation from the vitrified plant materials was very low. In order to improve the quality of in vitro propagated planting materials, the experiments were carried out using culture vessels capped with membrane filter(MF). When vitrified shoots were cultured on MS medium with 0.2mg/L BA in the vessels with MF or without MF for 60 days, the shoots in the vessels with MF did not vitrified. In contrast, the shoots grown in the vessels without MF vitrified at 65%. The stomates of vitrified leaves were circular and inflated, whereas those of normal leaves acclimatizated in the vessels with MF were ovate in shape. The hardened shoots were also cultured on MS media without sucrose containing 0.01mg/L IBA in vessels with(photoautotrophic culture) or without(control) MF. Sucrose was necessary for survival of the in vitro plantlets in the vessels without MF. After 20 days of culture, the shoots in the vessels without MF on the sucrose-free media turned yellow and died. But the shoots in the vessels with MF in the sucrose-free media produced a lot of roots. When shoots were cultured on MS medium with 2% sucrose containing 0.01mg/L IBA in the vessels with(photomixotrophic culture) or without(heterotrophic culture) MF, best growth occured in photomixotrophic culture.

• Journal of Life Science
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• v.21 no.2
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• pp.309-315
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• 2011

Rice syrup meal (RSM) was enzymatically hydrolyzed using eight commercial proteases (Protamex, Neutrase, Flavourzyme, Alcalase, Protease M, Protease N, Protease A, Molsin F) for 4 hr at optimum pH and temperature. Proteolytic hydrolysates were examined in supernatant and precipitate using Lowry protein assay, semimicro Kjeldahl method and gravimetric method using weight difference before and after enzymatic hydrolysis. Although RSM contains a high amount of protein (71.2%), only a very small amount of protein was hydrolyzed. Two proteases (Protease M and Protease N) were found to be the most effective in the hydrolysis of RSM protein. In Lowry method, 57.5 and 59.0 mg protein/g RSM were hydrolyzed after Protease M and Protease N treatments, respectively. In gravimetric method, 80.0 and 85.4 mg protein/g RSM were hydrolyzed after Protease M and Protease N treatments. In Kjeldahl method, 67.43 and 70.43 mg protein/g RSM were hydrolyzed after Protamex and Protease N treatments, respectively. For synergistic effect, two or three effective commercial proteases (Protease M, Protease N and Protease A) were applied to RSM at one time. The highest hydrolysis of RSM protein was observed in both Lowry protein assay (80.3 mg protein/g RSM) and gravimetric methods (153.2 mg protein/g RSM) when three commercial proteases were applied at one time, suggesting the synergistic effect of those proteases.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.260-269
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• 2009

Hwabuk Dam has been under construction to reduce flood damage in Nakdong River watershed and to supply stable water for middle area of Gyeongbuk Province. Therefore, fish investigation in up and downstream of the dam was conducted from 2004 to 2008 in order to determine any negative effect on fish community due to dam construction and to use as fundamental data for conserving species diversity and maintaining stream health. According to data analysis on water quality, temperature, dissolved oxygen, pH, suspended solids, and total E-coli had seasonal variation, but they did not significantly differ in sites. However, biological and chemical oxygen demand, chlorophyll-a, nitrogen, and phosphorus representing organic matter and nutrient concentration were higher in upper site and decreased to lower site so that they differed by site. Concentration of arsenic among the heavy metals was less than 0.05 mg $L^{-1}$, which is regulated for protection of human health in water quality standard, except for 0.092 mg $L^{-1}$ in June 2005. During the study period, the total number of fish caught from the 6 sites was 10,263 representing 7 families 19 species. Among them, dominant and subdominant species were Korean chub (Zacco koreanus, 62.5%) and Chinese minnow (Rhynchocypris oxycephalus, 10.6%) which inhabit mostly in mid and upper streams, Korea. Among the 19 species, Korean endemic species were 9 species (47.4%) including Korean slender gudgeon (Squalidus gracilis majimae), Korean dark sleeper (Odontobutis platycephala), and Korean shiner (Coreoleuciscus splendidus). There was several individuals of the $1^{st}$-class endangered species, Naktong nose loach (Koreocobitis nahtongensis), caught in 2005${\sim}$2007, and no introduced species of fish was found in entire sampling period. According to result of community analysis, dominance index decreased toward lower site, but diversity and richness indices increased toward lower site. The equation of length-weight relationship on the dominant species was TW=0.000003$(TL)^{3.2603}$. The parameter b in the equation was greater than 3.0 indicating good nutritional condition in the populations. Compared to populations of Korean chub in other streams, the population in Hwabuk Dam watershed had higher mean of condition factor by size indicating better growth rate. With fish fauna and multi-metric health assessment model in each sampling attempt, index of biotic integrity (IBI) was evaluated and it resulted mostly in good (26${\sim}$35) and excellent (36${\sim}$40) condition in all sites, and the mean of IBI was the highest in site 5. The results indicate that it is very important to study not only environmental impact assessment with fish composition but also stream health assessment in order to conserve healthy aquatic ecosystem.

• Korean Journal of Food Science and Technology
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• v.50 no.1
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• pp.44-54
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• 2018

To maintain the best quality of kimchi during long-term storage, we developed a fermentation storage mode for the kimchi refrigerator. The optimal kimchi fermentation temperature was determined to be $6^{\circ}C$ with fermentation time of 4-7 days in winter and 3-5 days in spring and fall. Based on these results, the fermentation storage mode conditions were programmed to consist of a fermentation temperature of $6^{\circ}C$ and fermentation times of 111 h in winter and 58 h in spring/fall. When kimchi was stored under the developed fermentation storage mode conditions, the total acidity of kimchi was almost the same as that of the control kimchi (stored $-2-\;-1^{\circ}C$ for 12 weeks). However, the number of lactic acid bacteria (LAB) and Leuconostoc sp. in kimchi were higher ($10^1-10^2CFU/mL$) than those in the control kimchi during storage. In addition, kimchi fermented and stored under the fermentation storage mode clearly received higher scores for overall preference than the control kimchi.

• The Korean Journal of Food And Nutrition
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• v.28 no.2
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• pp.269-280
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• 2015

The purpose of this study was to investigate the dietary habits, health status, and nutrients status of male college students in Seoul according to vegetarian habits. The heights of lacto-ovo vegetarian and non-vegetarian students were not significantly different. However, body weight was significantly higher in the non-vegetarians. The lacto-ovo-vegetarians were vegetarians for religious reasons, and indicated 86.0% satisfaction with their meals. However, the lacto-ovo vegetarian and non-vegetarians showed concerns about low nutrient intakes. Lacto-ovo vegetarians displayed a higher proportion of meal regularity and daily breakfast as compared to non-vegetarians. In addition, their favorite food when eating out was Korean food. Lacto-ovo vegetarians showed higher intakes of milk or other dairy products (yogurt, etc.), vegetables, and fruit, as well as more regular eating habits. In contrast, the non-vegetarians showed higher intakes of high-protein foods (eggs, beans, tofu, etc.) and fatty foods. Lacto-ovo vegetarians showed lower intakes of total energy, as well as vitamins $B_2$, $B_6$, and niacin. Non-vegetarians showed in sufficient dietary fiber intake. In conclusion, lacto-ovo-vegetarians need a meal plan to consider the intake of other nutrients, while non-vegetarians should try to prevent the occurrence of health problems due to excessive intake of nutrients.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.466-471
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• 2010

This study investigated the effects of dietary supplementation of fermented apple pomace (FAP), fermented pear pomace (FPP), fermented orange pomace (FOP), and fermented Angelica keiskei Koidz pomace (FAKP) on performance, shelf life, fatty acid composition and cholesterol in broiler chickens. A total of 600, 1-day-old male broiler chicks (Cobb strain) were randomly divided into six groups with four replicates of 30 birds each. There were five treatment groups: control (C), FAP (1.0%, T1), FPP (1.0%, T2), FOP (1.0%, T3), and FAKP (1.0%, T4). The body weight of the broiler chickens fed FAP diet was higher (1,758 g) than the other treatments. There was no difference in the thiobarbituric acid reactive substances (TBARS) in chicken meat between all groups at days 1, 3, and 5 of storage, while the FAP-supplemented group displayed lower TBARS values at day 7. There was no significant difference in fatty acid composition between the groups but the cholesterol content of chicken meat was lower than the control groups. These results suggest the possibility that FAP could be used as a functional feed to improvement the quality performance of broiler chickens.

• Korean journal of food and cookery science
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• v.13 no.3
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• pp.272-277
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• 1997

To evaluate the quality of commercial anchovy sauces, 8 varieties (2 products from the Fishery Cooperation, 2 from small companies, and 4 well-known brands) were chosen and their physicochemical and sensory properties were examined. The salinity of anchovy sauces ranged from 19.8％ to 26%, where product E was the saltiest and followed by F> H > B > E > A> C = G > D. Product D with the least salinity was turbid, rancid, and high in ammonia content, suggesting that it is difficult to control the quality of anchovy source with a low salt content. Protein content of anchovy sauces ranged from 2.51％ to 2.64%. The unit price of anchovy source A was the highest, whereas B was the lowest. Sensory evaluation scores of anchovy sauces were in the order of B > G > A > F > E > C > H > D for color, B > G = C > H > E = F > G > D for odor, E > C > F > G > H > D > B > A for saltiness, and B > A > C > H > E = F > G > D for overall acceptability. Above results suggest that product B was the best in quality as well as the cheapest among all. Based on the above results, kimchies were prepared with product A, B, C with a high sensory quality and product H with a high market occupancy, and sensory evaluation was performed. The kimchi with product C got the highest sensory score in appearance and the one with product A and H in odor. Although the kimchi with product A generally had high scores throughout the fermentation period, there were no significant differences in texture, salty taste, and overall acceptability among kimchies with different varieties of anchovy sauces.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.874-882
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• 2017

As the interest on the air-pollution is gradually rising up at home and abroad, automotiv e and fuel researchers have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research has brought forward three main issues : evaporative, performance, air pollution. In addition, researcher studied the environment problems of the bio-ethanol, bio-butanol, bio-ETBE (Ethyl Tertiary Butyl Ether), MTBE (Methyl Tert iary Butyl Ether) fuel contained in the fuel as octane number improver. The researchers have many dat a about the health effects of ingestion of octane number improver. However, the data support the con clusion that octane number improver is a potential human carcinogen at high doses. Based on the bio-fuel and octane number improver types (bio-ethanol, bio-butanol, bio-ETBE, MTBE), this paper dis cussed the influence of gasoline fuel properties on the evaporative emission characteristics. Also, this p aper assessed the acceleration and power performance of gasoline vehicle for the bio-fuel property. As a result of the experiment, it was found that all the test fuels meet the domestic exhaust gas standards, and as a result of measurement of the vapor pressure of the test fuels, the bio - ethanol : 15 kPa and the biobutanol : 1.6 kPa. thus when manufacturing E3 fuel, Increasing the biobutanol content reduces evaporation gas and vapor pressure. In addition, Similar accelerating and powering performance was shown for the type of biofuel and when bio-butanol and bio-ethanol were compared accelerated perf ormance was improved by about 3.9% and vehicle power by 0.8%.

• Journal of the Korean Institute of Gas
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• v.8 no.2 s.23
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• pp.15-27
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• 2004

The purpose of this paper is to improve the performance of Polymer electrolyte fuel cell(PEMFC) by studying the channel dimension of bipolar plates using commercial CFD program 'Fluent'. Simulations are done ranging from 0.5 to 3.0mm for different size in order to find the channel size which shoves the highst hydrogen consumption. The results showed that the smaller channel width, land width, channel depth, the higher hydrogen consumption in anode. When channel width is increased, the pressure drop in channel is decreased because total channel length Is decreased, and when land width is increased, the net hydrogen consumption is decreased because hydrogen is diffused under the land width. It is also found that the influence of hydrogen consumption is larger at different channel width than it at different land width. The change of hydrogen consumption with different channel depth isn't as large as it with different channel width, but channel depth has to be small as can as it does because it has influence on the volume of bipolar plates. however the hydrogen utilization among the channel sizes more than 1.0mm which can be machined in reality is the most at channel width 1.0, land width 1.0, channel depth 0.5mm and considered as optimum channel size. The fuel cell combined with 2cm${\times}$2cm diagonal or serpentine type flow field and MEA(Membrane Electrode Assembly) is tested using 100W PEMFC test station to confirm that the channel size studied in simulation. The results showed that diagonal and serpentine flow field have similarly high OCV and current density of diagonal (low field is higher($2-40mA/m^2$) than that of serpentine flow field under 0.6 voltage, but the current density of serpentine type has higher performance($5-10mA/m^2$) than that of diagonal flow field under 0.7-0.8 voltage.