• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.18-24
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• 2007

Paddy fields are apparently nonpoint source pollution and influence water environment. In order to improve water quality in rivers or lakes, to low nutrient load from paddy fields are required. To establish comprehensive plan to control agricultural non-point source pollution, it is imperative to get a quantitative evaluation on pollutants and pollution load from paddy fields. A field monitoring study was carried out to investigate the water balance and losses of nutrients from fields in Sumjin river basin. The size of paddy fields was 115 ha and the fields were irrigated from a pumping station. The observed total nitrogen loads from paddy fields were larger than those of the unit loads determined by Ministry of Environment data (MOE). It is because the nitrogen fertilization level at the studied field was higher than the recommended rate and the high irrigation and subsequent drainage amount. On the contrary, total phosphorus loads were less than those addressed by MOE since phosphorus fertilization level was lower than that of standard level. Therefore, it was found that fertilization, irrigation, and drainage management are key factors to determine nutrient losses from paddy fields. When the runoff losses of nutrients were compared to applied chemical fertilizer, it was found that 42 to 60% of nitrogen lost via runoff while runoff losses of phosphorus account for 1.3 to 7.6% of the total applied amount during the entire year.

• Korean Journal of Environmental Agriculture
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• v.15 no.4
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• pp.406-418
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• 1996

Tomatoes are water logged differently 0, 5, 10 and 15 cm, according to the developing stages such as germination and seedling stage under the condition of greenhouse. Along with this, they are treated according to the time condition such as 6, 12, 24, 48 and 120 hours. The results obtained are summarized as follows. 1. The result at germination stage Remarkable germination failure was observed when tomatoes were water-logged for 25 to 27 hours in the depth of 0 to 5 cm. Plant height recovered within 24 hours regardless of the water-logging depths. In the case of leaves, the recoverable time limit became shorter gradually in accordance with the increase of the water-logging depth. The decrease of the fresh weight showed acute response in the shoot rather than the root. It recovered with the 24 hours of water logging. Significant correlation was observed in all characteristics of plant height, number of leaves, fresh weight and germination rates according to the depth of water-logging. 2. The result at seedling stage Plant height recovered within the 24 hours of water-logging in the depth of 0 cm. On the deeper level, there was significant decrease regardless of time. With regard to the number of leaves, there was recovery up to 120 hours in the depth of 0 cm, up to 24 hours in the depth of 5 cm. There was, however, significant decrease when done for more than 6 hours on the deeper level. Growth of the shoot displayed the same tendency as in plant height and number of leave. The length of the longest root could be maintained by 80% in the water-logging of 0 cm compared with control. However in depth of 5 cm or more, it could not be maintained by the 120 hours water-logging. Root activity became conspicuously diminished with the logging over 0 cm. Respiration showed conspicuous decrease by the depth of 5 cm as a turning point. On the other hand, photosynthesis became decreased linearly by the depth of water-logging. Chlorophyll content displayed gradual decrease up to 48 hours, but conspicuously decreased up to 120 hours according to the varying depth of water-logging. Dieases tended to increase according to the depth and hours of water-logging. Diseases would be prevented by dint of insecticide, but there was no effect of fertilization. Weight and number of fruit per plant displayed gradual decrease as the depth and hours of water-logging became increased. Average weight of a fruit became increased. There was no statisticaly reciprocal effects between the depth and hours of water-logging. There was significant positive correlation among all the investigated characteristics, such as traits of growth and yield.

• Journal of Yeungnam Medical Science
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• v.14 no.1
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• pp.123-136
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• 1997

The purpose of this study was to examine the reliability and validity of a Korean form of Childhood Attention Problem(CAP) scale. CAP were administered to 98 normal elementary school students as control group and 98 attention deficit hyperactivity disorder patients. Male students showed high scores than female students in both subscale and total scores, but not statistically significant. There were no significant difference in CAP scale between male students and female students in attention deficit hyperactivity disorder patients. In the reliability test, the test-retest reliability coefficient was highly satisfactory and that of inattention subscale was 0.83, impulsivity subscale was 0.70 and total score was 0.82. In the reliability test by internal consistency, the Cronbach $\alpha$ coefficient was highly satisfactory and that of inattention subscale was 0.91, overactivity subscale was 0.89(p<0.05). The concurrent validity between CAP scale and ADDES-BV scale was 0.85 in attention deficit hyperactivity disorder patient group and 0.73 in normal control group(p<0.05). In discriminant validity test between attention deficit hyperactivity disorder patient group and normal control group, the patient group showed higher score(p<0.05). The total discriminant capacity of the patient group in CAP was 93.4%. In this point of view, CAP scale showed high reliability and validity in applying to Korean subjects and was proved to be the good and simple screening test tool for attention deficit hyperactivity disorder research and can help many young patient to treat early.

• The Korean Journal of Pharmacology
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• v.19 no.1
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• pp.123-131
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• 1983

1) To delineate the role of central ${\alpha}_2-adrenoceptors$ in the pressor response to raised intracranial pressure(ICP), the influence of yohimbine, an ${alpha}_2-adrenoceptor$ antagonist, on the pressor response to raised ICP was investigated in urethane-anesthetized rabbits. 2) The ICP was raised by infusing saline into a balloon placed in the epidural space. The rise of ICP was slow in the beginning of the infusion but it became sharp as the infusion proceeded. 3) In response to raised ICP, blood pressure(BP) tended to decrease slightly in the beginning and then increased sharply. BP, however, fell abruptly and markedly if ICP was raised further. The maximal pressor response to raised ICP was the increase of $49{\pm}2.4%$ of the original $BP(mean{\pm}SE\;in\;32\;experiments)$, and at this point the volume of saline infused into the balloon was $1.22{\pm}0.15\;ml$, and the ICP $165{\pm}6.4\;mmHg$. 4) Intraventricular yohimbine $(50{\mu}g)$ by itself did not affect BP. After the administration of this dose of yohimbine the increase of both ICP and BP was observed after the infusion of much smaller volume of saline than in the control animals, i.e., after the infusion of $0.83{\pm}0.02\;ml$ of saline the maximal increase of preesor response$(57{\pm}4.5%\;in\;6\;experiments)$ appeared and at this state the ICP was $164{\pm}9.6\;mmHg$. 5) Intraventricular $clonidine(30{\mu}g)$ markedly decreased BP by itself, and in the clonidine-treated rabbits the increase of ICP induced by the infusion was much less than in the control group and the pressor response to raised ICP was hardly seen. 6) The hypotensive effect of intraventricular clonidine was reversed by a susequent intraventricular $yohimbine(500\;{\mu}g)$. At this state the pressor response to raised ICP appeared as in the control animals. 7) These results show that the pressor response to raised ICP was facilitated when ${\alpha}_2-adrenoceptors$ in the rabbit brain was blocked by yohimbine and that yohimbine antagonized the inhibitory effect of clonidine on the pressor response to raised ICP.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.5
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• pp.81-94
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• 2022

This study analyzed the effect of the entrepreneurship planning course provided by an women's university in Seoul on the enhancement of the core competencies of entrepreneurship of university students. To this end, pre- and post-test of core entrepreneurship competency were conducted on 63 female university students (32 in experimental group, 31 in control group) and then the results were analyzed. The course in which the experimental group participated was a team-based project learning course and it required a team of three people to draw an entrepreneurship plan containing social problem solving as the final result. The course was operated for a total of 8 weeks. To measure the level of entrepreneurship core competency in the pre- and post- test, the survey tool that was developed by the Ministry of Education and Korea Entrepreneurship Foundation (2020) was used. This tool composed by 'value creation', 'challenge', 'self-directed', and 'group creativity' competencies. As analyses methods, i) covariance analysis was performed using the pretest as a covariate, and then a two-way ANOVA was performed with treatment (experimental group, control group) and time point (pre test, post test) as two independent variables. Results show while there was no significant difference between the experimental group and the control group in the value creation competency, it significantly contributed to the enhancement of challenge, self-directed, and collective creativity competencies. Based on these results, implications and limitations were discussed, followed by future research direction.

• Journal of Energy Engineering
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• v.17 no.3
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• pp.139-144
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• 2008

Recently due to march as the high oil price, It is necessary for Korea to grope a plan, which is to increase the energy efficiency of existing facilities as well as to develop overseas gas and oil resources. With this point, this work carried out to approach the high pressure LNG pipeline network of Inchon receiving terminal with Newton method as corrective flowrate. We found that the high pressure network mainly depends on FCVs(Flow Control Valves). The high pressure pump showed the maximum efficiency at the FCVs of 50% opening and could discharge LNG only above the LNG head of 1,500m from a system curve obtained. The operating cost of pumps was estimated from their operating points. We compared the operating cost under normal operation with the operating cost under maximum efficiency. Especially, we obtained the day savings of a year as wells as the hour savings of a day. From the results, the high pressure network win be able to reduce the operating cost of 138 million wons in a year. This means that a pump can reduce the operating cost of 9,823 thousands won. Consequently, this work could find the operating features of the pumps under the complicated high pressure LNG network and the savings effect of the pump operating cost. Also, the results will be able to macroscopically contribute the heightening of national energy competitiveness as well as to microscopically contribute the future effective operation of LNG receiving terminal.

• Journal of the Korean Society of School Health
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• v.5 no.1
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• pp.101-110
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• 1992

We investigated each 50 students in the primary school its 1st year student(boys & girls) on the conditions of oral hygiene between urban and rural children centering around the dental caries. The purpose of this study is to promote national oral health and to offer the basic data on the oral health level of community. We got conclusion as follows : 1. Sex : The prevalence rate of dental caries between the rural and urban children showed high to the urban children. 2. Education Level of Parents : When the educational background of father is high, the prevalence rate of dental caries showed high(P<0.01). The educational background of mother has not influenced on the prevalence rate. 3. Economic Level of Home : When the economic level of home is high, the prevalence rate of dental caries is high(P<0.01). 4. Intake Frequency of Eating Between Meals : The average intake frequency of eating between meals a day of urban children was $2.3{\pm}0.76times$, the average intake frequency of eating between males a day of urban children was $2.79{\pm}0.82times$(P<0.01). 5. Brushing Frequency : The average brushing a day of rural children was $2.48{\pm}0.82times$, urban children was $2.34{\pm}0.71times$, and when the brushing frequency is high, the prevalence rate of dental caries showed low(P<0.01). 6. Brushing Time : The rural children and urban children had no difference, but brushing time had influenced on the prevalence rate(P<0.01). 7. Kinds of Drinking Water: The kinds of drinking water had not influenced on the prevalence rate of dental caries. 8. Amount of Pocket Money : The urban children is the more amount of pocket money than the rural, when the amount of pocket money is lots, the prevalence rate of dental caries showed high(P<0.01). 9. Average Intake Frequency a day for the caries food of eating between meals of rural children was 2.91 times and urban children was 3.47 times. The average intake frequency a day for the caries food of eating between meals had influenced on the prevalence rate dental caries. In the point of view for the oral health, the urban children is bad than the rural children in the actual conditions of intake. The education of oral health for parents has demanded, the necessity of oral control for the children of the improvement effectively as the methods to maintain the oral health level.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.4
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• pp.345-356
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• 2011

Based on the consideration of land based pollutant discharges from the basin and seawater quality related carrying capacity and the seawater quality improvement in receiving water bodies of Yeoja Bay where eutrophication and organic pollution are in progress, were evaluated. The permissible inflow loads of BOD, TN and TP by using the geographical features and box modelling method were estimated. As results, it is shown that the reduction rate of discharged BOD and TP loads were 39.3% and 30.8 %, respectively, however, 6.9% was estimated for TN. According to the pollutant loading in each tributary and generated load of the basin, it is given much weight on the land use group, and also was shown in discharged load estimation. This suggests that it is important to control nonpoint source pollutant such as livestock and land use groups as well as point source to contribute the proposition of the water quality improvement plan according to the characteristics of the bay.

• Journal of the Korea Concrete Institute
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• v.23 no.5
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• pp.617-626
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• 2011

Seven post-tensioned lightweight concrete (LWC) beam specimens were tested under a symmetrical two-point top loading system. The parameters investigated were the amounts of mild longitudinal reinforcement and effective prestressing. The design compressive strength and dry density of the LWC tested were 30 MPa and 1,770 $kg/m^3$, respectively. Similar to post-tensioned normal weight concrete (NWC) beams, the crack propagation and stress increase of the unbonded tendons were significantly affected by the amounts of mild longitudinal reinforcement and effective prestressing. With the increase in the amounts of mild longitudinal reinforcement and effective prestressing, the serviceability and flexural capacity of the beams were enhanced whereas the stress increase in the unbonded tendons decreased. To control the crack width in post-tensioned LWC beams, a minimum amount of mild longitudinal reinforcement specified in ACI 318-08 provision is required. The flexural behavior of post-tensioned LWC beams and stress increase of the unbonded tendons could be rationally predicted by the proposed non-linear two-dimensional analysis. On the other hand, ACI 318-08 flexure provision was too conservative about the post-tensioned LWC beams.

• Analytical Science and Technology
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• v.25 no.6
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• pp.382-387
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• 2012

Ethylene oxide ($C_2H_4O$, EtO) is used as a raw material for the production of ethylene glycol and other industrially important material such as ethanolamines and also used as a disinfecting agent. It is applied for gas-phase sterilization of thermally sensitive medical equipment, and for processing of storage facilities as a mixture with fluorinated hydrocarbon. In this perspective, accurate determination of the mole fractions of components in the liquefied gas mixture is required for the quality control and safety of production and use. Each component of the liquefied gas mixture has different chemical and physical properties such as vapor pressure and boiling point. Therefore, we can suppose that analytical results can be different according to the introduction method for the gas phase of upper layer, or for the liquid phase of lower layer in gas cylinder. In this study, we designed a new on-line sample injection device for the liquefied gas mixture in liquid or gas state, and applied to the analysis of liquefied gas mixture of ethylene oxide and fluorinated hydrocarbons by GC/AED (gas chromatograph-atomic emission detector). We studied performance of AED, and effect of sample introduction and selected wavelength to the accuracy and repeatability of analytical results.