• Food Science of Animal Resources
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• v.28 no.4
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• pp.480-485
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• 2008

In this experiment, 5 treatments consisted of control, probiotics (0.2%; T1), illite (1.0%; T2), activated carbon (1.0%; T3), and hardwood vinegar (1.0%; T4) as diets of chicken were evaluated for 35 days through feeding of 200 male chickens (Arbor Acre Broiler). Thigh muscle from slaughtered chickens were analyzed on pH, volatile basic nitrogen (VBN), thiobarbituric acid reactive substance (TBARS), shear force, and meat color during 10 d of cold storage at $4{\pm}1^{\circ}C$. Groups of T3 and T4 showed higher pH levels compared to the control group, and T4 showed significantly higher value. Over the storage period, all treatment groups showed increase in pH (p<0.05). Values of VBN of T1, T3, and T4 were lower than those of the control group and T2 up to 7 d of storage (p<0.05), but there was no significance at 10 d of storage. Values of TBARS of T3 and T4 were lower than the control group, T1, and T2, while all treated groups showed rapid increase of TBARS values over storage period (p<0.05). Shear force did not show significant difference among treated groups, but it was decreased over storage. Lightness of meat color (L) in treated groups was higher than the control, and T4 showed the highest value during entire storage period (p<0.05). Yellowness levels (b) of T3 and T4 were higher than the control group. These results may suggest the improvement of chicken meat quality and shelf life via the addition 1% activated carbon and 1% hardwood vinegar into feed.

• Food Science of Animal Resources
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• v.28 no.4
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• pp.505-511
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• 2008

The goal of this study was to investigate the effects of dietary mugwort on the proximate composition, volatile basic nitrogen (VBN), thiobarbituric acid reactive substance (TBARS) and fatty acid in chicken meats. One hundred sixty broiler chicks (1 d old) were assigned to one or four dietary groups: Control; commercial feed supplemented with 1% mugwort (T1); commercial feed with 3% mugwort (T2) and commercial feed with 5% mugwort (T3). After 42 d, broilers from each group were slaughtered and meat samples were vacuum packaged and stored at $4{\pm}1^{\circ}C$ over a period of 0, 1,2,3, and 4 wk. Chicken breast was not influenced by all treatments in moisture, crude protein and crude fiber, while crude fat was lowered (p<0.05) in chickens fed with the T2 and T3 diets compared to the control and T1 diets. All treatments with mugwort diets tended to have decreased VBN values for chicken breast and thigh compared to control. As storage time increased, VBN was increased for all chickens (p<0.05). No significant differences in TBARS were observed among all treatments at 0 wk. TBARS values were reduced with the T2 and T3 diets and initially increased from 0 through 3 wk, then abruptly decreased at 4 wk. Dietary mugwort supplementation resulted in increased stearic acid (excepted T2) and oleic acid and decreased linoleic acid. Stearic acid in thigh meat was decreased in the T1, T2 and T3, however linoleic acid levels tended to increase with mugwort powder supplementation. It is concluded that dietary mugwort has a positive effect on increasing unsaturated fatty acid contents and decreasing saturated fatty acids.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.5
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• pp.187-200
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• 2019

The main purpose of this study is to investigate the effects of motivation of the employment in Korea with gender, nationality, motivation of studying in Korea, major satisfaction and Korean proficiency level of foreign students who are studying in Korea. The second purpose is to analyze the current factors, to leverage educational management and to make and support some policy of Minister of Education for international students in order to promote utilization of employment of the students in Korea during 4 years of studying. This paper is used by IBM SPSS Statistics 24 Version for data analysis. As a result of the analysis, the average of students in Southeast Asia, Central Asia and South and North America Africa was higher than Japan and China in terms of motivation of employment in Korea. First, the external motivation to study in Korea has affected TOPIK with positive influence. Second, in the relationship between motivation to study in Korea and the majors satisfaction, the higher the internal motivation of study, the higher the majors' satisfaction level. Third, in the relationship between motivation to study in Korea and motivation of the employment in Korea, internal motivation to study has a positive effect on motivation of the employment. As internal motivation increases, grade of the motivation of the employment increases. Fourth, the relationship between major satisfaction and employment showed positive (+) effect. In other words, the higher the major satisfaction, the higher the motivation of the employment. Fifth, TOPIK has a negative effect on motivation of the employment. It means that external motivation was the main factor that positively influenced TOPIK and internal motivation was also main factors that positively influenced both major satisfaction and motivation of the employment in Korea. Sixth, when the internal motivation has an effect on motivation of Korea employment, the higher the major satisfaction as the parameter, the higher the motivation of Korea employment. Therefore, it will be helpful to understand the meaning of studying motivation and major satisfaction of international students, and to be used as basic data on education policies of universities and governments supporting the career and employment for international students.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.2
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• pp.165-175
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• 1995

To determine the effect of soil moisture stress on growth of barley and grain quality, a pot experiment was carried out for two barley varieties(Olbori and Chogangbori) by using large plastic pot(52cm in diameter and 55cm in depth) filled with sandy loam soil under rain-controlled open green house. By means of measuring soil water potential with micro tensiometer and gypsum block installed at 10cm in soil depth, soil moisture was controlled by sub-irrigation at several irigation points such as -0.05bar, -0.2bar, -0.5bar, -1.0bar, -5.0bar and -10.0bar in soil water potential. The lower soil water potential was controlled, the shorter length of stem and internode became, and the more narrow stem diameter was. Leaf area was significantly decreased when soil water potential was controlled lower than -0.5bar, although chlorophyll content of flag and first leaves was not changed so much. Weight of grain and ear was significantly decreased when soil water potential was lower than -5.0bar and the highest grain yield was obtaind in a plot where soil water potential was controlled at -0.2bar. However, the most efficient water use of Olbori and Chogangbori was obtained at -0.5bar and -1.0bar in water potentials, respectively. Crude protain content, maximum viscosity, consistency and ${\beta}$-glucan content of barley flour increased as soil water potential significantly decreased, especially below -5.0bar, but gelatination temperature decreased as soil water potential decreased.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.447-453
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• 2007

With a broad objective for the development of microbial based fertilizers, a total of 373 strains were isolated from rhizoplane and rhizosphere of pepper, tomato, lettuce, pasture, and grass. The efficacy of the isolates to augument overall plant growth was evaluated. After screening for their plant growth promotion and antagonistic properties in vitro efficient strains were further selected. The most efficient strains was characterized by 16S rRNA gene sequences and biochemical techniques and was designated as Bacillus subtilis S37-2. The strains facilitated plant growth and inhibited the plant phathogenic fungi such as Fusarium oxysporum (KACC 40037, Rhizoctonia solani (KACC 40140), and Sclerotinia sclerotiorum (KACC 40457). Pot based bioassay using lettuce as test plant was conducted by inoculating suspension ($10^5$ to $10^8cells\;mL^{-1}$) of B. subtilis S37-2 to the rhizosphere of lettuce cultivated in soil pots. Compared with non-inoculated pots, marked increase in leaf (42.3%) and root mass (48.7%) was observed in the inoculation group where the 50ml of cell mixture ($8.7{\times}10^8cells\;ml^{-1}$) was applied to the rhizosphere of letuce either once or twice. Antagonistic effects of B. subtilis S37-2 strain on S. sclerotiorum (KACC 40457) were tested. All the tested lettuce plants perished after 9 days in treatment containing only S. sclerotiorum, but only 17% of lettuce was perished in the inoculation plot. B. subtilis grew well in the TSB culture medium. The isolates grew better in yeast extracts than peptone and tryptone as nitrogen source. The growth rate was 2~4 times greater at $37^{\circ}C$ as compared with $30^{\circ}C$ incubation temperature. B. subitlis S37-2 produced $0.1{\mu}g\;ml^{-1}$ of IAA (indole 3-acetic acid) in the TSB medium containing L-tryptophan($20mg\;L^{-1}$) in 24 hours.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.320-327
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• 2021

Freezing damage to fruit trees is frequently occurring due to cold in winter and low temperature in spring to abnormal weather caused by global warming. In particular, the freezing injury of deciduous fruit trees is highly dependent on the developmental stages of the flower buds. And the cold resistance is weakened as the growth progresses, so it is most vulnerable period from flowering to petal fall(post-bloom). Therefore, this study was conducted to analyze the cause of the freezing injury caused by severe low temperature to 'Fuji', which has a late flowering period more than 'Hongro' in April 2020. We investigated freezing injury rate in 'Fuji' and 'Hongro' apple trees damaged by natural low temperature at Boeun-gun, Chungbuk province in Korea. In addition, flower buds in the same developmental stage (tight cluster) were treated artificially low temperature to investigate the injury rate for accurate comparative analysis between varieties, and to analyze the soluble sugar and hormone contents in the flower buds. As a result of survey in natural low temperature, 'Fuji' had a higher injury rate than 'Hongro' in both orchards, and in particular, B orchard 'Fuji' had the highest injury rate of 60.5%. Also there were significantly difference in the freezing injury rate between 'Fuji' and 'Hongro' in artificially low temperature treatments. As a result of analyzing the soluble sugar contents in 'Hongro' was higher than 'Fuji'. Also ABA, IAA and SA contents were more increased in the damaged tissue than in the normal flower buds by low temperature treatments. Consequently, it was assumed that the freezing injury was closely related to soluble sugar contents in the flower buds. In particular, the freezing injury rate was negatively correlated with the sorbitol contents.

• Journal of the Korean GEO-environmental Society
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• v.22 no.10
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• pp.21-29
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• 2021

Most concrete gravity-type dams in and out of the country were constructed by column method to control cracks caused by concrete hydration heat generated during construction, resulting in a certain level of leakage after impoundment through various causes, such as contraction joints and construction joints. However, due to the characteristics of concrete structures that shrink and expand according to temperature, concrete dams have vertical joints and drains to allow penetration. PVC waterproof shows excellent effects in completion of the dam, which however increases the possibility of interfacial failure due to different thermal expansion. Other causes of penetration may include problems with quality control during installation, generation of cracks due to heat of hydration of concrete, waterproofing methods, etc. In the case of Bohyunsan Dam in Yeongcheon, North Gyeongsang Province, the amount of drainage in the gallery was checked and underwater, and it was confirmed that there are many penetrations from drainage holes connected to vertical joints, and that some of the PVC waterproofs are not fully operated. As a new method to prevent penetration through vertical joints, D.S.I.M. (Dam Sealing Innovation Method) developed by World E&C was applied to Bohyunsan Dam and checked the amount of drainage in the gallery. As a result of first testing three most leaking vertical joints, the drain in the gallery was reduced by 87% on the average and then applied to the remaining 13 locations, which showed a 83% reduction effect based on the total drain in the gallery. Summing up these results, it was found that D.S.I.M. preventing water leakage from the upstream face is a valid construction method to reduce the water see-through and penetration quantity seen in downstream faces of concrete dams. If D.S.I.M. is applied to other concrete dams at domestic and abroad, it is expected that it will be very effective to prevent water leakage through vertical joints that are visible from downstream faces.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.4
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• pp.296-304
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• 2018

The objective of this study was to analyze the impact of climate change on rice yield and quality. Experiments were conducted using SPAR(Soil-Plant-Atmosphere-Research) chambers, which was designed to create virtual future climate conditions, in the National Institute of Crop Science, Jeonju, Korea, in 2016. In the future climate conditions($+2.8^{\circ}C$ temp, 580 ppm $CO_2$) of year 2051~2060 according to RCP 8.5 scenario, elevated temperature and $CO_2$ accelerated the heading date by about five days than the present climate conditions, resulted in a high temperature environment during grain filling stage. Rice yield decreased sharply in the future climate conditions due to the high temperature induced poor ripening. And the spikelet numbers, ripening ratio, and 1000-grain weight of brown rice were significantly decreased compared to control. The rice grain quality was also decreased sharply, especially due to the increased immature grains. In the future climate conditions, expression of starch biosynthesis-related genes such as granule-bound starch synthase(GBSSI, GBSSII, SSIIa, SSIIb, SSIIIa), starch branching enzyme(BEIIb) and ADP-glucose pyrophosphorylase(AGPS1, AGPS2, AGPL2) were repressed in developing seeds, whereas starch degradation related genes such as ${\alpha}-amylase$(Amy1C, Amy3D, Amy3E) were induced. These results suggest that the reduction in yield and quality of rice in the future climate conditions is likely caused mainly by the poor grain filling by high temperature. Therefore, it is suggested to develop tolerant cultivars to high temperature during grain filling period and a new cropping system in order to ensure a high quality of rice in the future climate conditions.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.4
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• pp.273-279
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• 2018

This experiment was conducted to investigate the effects of individual management and group management of Jeju cross-bred horses on the physiological characteristics, productivity, and characteristics of the loin muscle of the horse meat. Sixteen herds of Jeju cross-bred horses older than 44 months were selected as experimental subjects. The experiment was conducted by dividing the herds into eight herds for individual management and another eight herds for group management. Herds were fed with concentrated feed of 2.5% of the body weight for four times a day and roughage and water were fed ad libitum. In the 12th week, the intestinal pH was statistically significantly lower with group management than with individual management (p<0.05). However, no symptoms of colic were observed. With regard to the general composition of the loin muscle, fat content was a statistically significant difference between the 7.83% with individual management and 5.65% with group management (p<0.05), indicating that individual management is more effective than group management in terms of fattening. In conclusion, feeding a concentrated feed at a level of 2.5% of body weight with individual management during fattening of Jeju cross-bred horses could be utilized as a fattening method.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.4
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• pp.53-68
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• 2020

The concentrations of ammonia, hydrogen sulfide and fine dust were measured in the compost facility of a full-time Hanwoo breeding farms. The experiments were conducted in stack type composting facility(T1) and mechanical-stirred composting facilities(T2, T3). In the stack type composting facility, the highest temperature of compost pile was 46℃, and in the two mechanical-stirred composting facilities, it rose to 63℃ and 68℃, respectively. The concentrations of PM2.5 at T1, T2 were 15 ㎍/㎥ and 5~10 ㎍/㎥, respectively. And the concentration of PM2.5 at T3 was below 10 ㎍/㎥. The highest concentration of ammonia generated at T1 was 4 ppm, but no hydrogen sulfide was detected. The ammonia concentrations at T2 and T3 were 3 ppm and 4 ppm, respectively. However, hydrogen sulfide was not detected in both facilities. At T3, the ammonia concentration increased to 65 ppm at the point where the compost was stirred with a mechanical agitator. During composting period, the pH of the compost pile decreased from 9.06 to 8.94 and then increased to 9.14 as the composting period elapsed. The NaCl content of compost was 0.09% after composting process was complete. Moisture content of compost decreased from 65.9% to 62% as composting progressed. As composting proceeded, the content of volatile solids decreased from 65.6% to 64.7% and the content of TKN decreased from 1.327% to 1.095%.