• Journal of agricultural medicine and community health
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• v.12 no.1
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• pp.80-93
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• 1987

Mass chemotherapy of Clonorchis sinensis infection in Korea was started in 1982 with 40mg/kg body weight single dose administration scheme of praziquantel. The purpose of this study was to investigate the efficiency of current mass chemotherapy project and compare the epidemiological changes in endemic area of Ckmorchis sinensis. This study was performed at Kimhae-city and Samrangjin-eup of Miryang-gun, Kyongnam province, highly endemic area of C. sinensis located southeastern part of Korea from July to October of 1986. The therapy project of Kimhae area was performed in 1984, whereas that of Samrangjin was done in 1985 by stool examination of the Korea Association for Parasite Eradication(KAPE) and drug administration of local health centre. The results obtained were as follows; 1) As a results of stool examination from 234 specimens obtained in Kimhae area, the infection rate has decreased to 34.2%from 45.6p in 1983, but the infection rate of C. sinensis from 341 specimens obtained in Samrangjin area did not decrease (58.1%in 1986 490%in 1983). 2) The study in Kimhae area showed that the average EPG decreased remarkably from 4,858 to 1,340 and those classified above the category of heavy infection decreased also from 14.0pp to 1.7%. The study in Samrangjin area showed that the average EPG did decrease drastically from 9,597 to 6,498 and those classified above the category of heavy infection did not go down drastically from 25.2% to 14.2%. 3) The study in Kimhae area showed decrease of Cs.$D._{50}$ in comparison to that in 1983, wheareas Cs.$D._{50}$ in Samrangjin area showed no much difference compared to that in 1983. The intensities of endemicity were represented with the regression equation calculated with the cumulative percentages of EPG count. Regression equation was Y=4.49+1.19 log x in Kimhae area and Y=3.66+127 log x in Samrangjin area. 4) The two stage catalytic model was applied and the calculation lead to the equation $Y=5.33(e^{-0.018t}-e^{-0.016t})$ in Kimhae area and $Y=1.25(e^{-0.010t}-e^{-0.018t})$ in Kimhae area and $Y=125(e^{-0.010t}-e^{-0.050t})$ in Samrangjin area 5) The infection rate of cercaria in P.manchouric-us studied in Kimhae area showed 1.25% which is not much different from that in previous years, wheareas the infection rate of metacercaria in P. parva studied in the same area this year showed 2.5-20.2/gm of flesh in comparison to 64/gm of flesh in 1983. 6) Data of C. sinensis infection on the reservoir host in Kimhae area showed 4 out of 18 dogs, 1 out of 18 rats and that in Samrangjin area showed 2 out of 18 dogs respectively. 7) Among the inhabitants who were under mass chemotherapy in Kimhae area, 71out of them, upon stool examination, showed infection rate of 66.2% and those classified above the category of heavy infection, 2.4%. In comparison to infection rate of 33.7% and those classified above the category of heavy infection, which is 1.0%, obtained from those not under mass chemotherapy showed higher infection rate and somewhat equal distribution of intensity of infection. The above statements reflect the fact that individual therapy besides mass chemotherapy was prevalent in that area. 8) On the other side, the studies in Samrangjin area showed infection rate of 68.7% and those above the category of heavy infection, which is 6.1%, in comparison to infection rate of 58.3% and those above the category of heavy infection, which is 16.5%, in those not under mass chemotherapy. the above reflects that although a good deal of inhabit-ants were classified under light or moderate infection category, those above the category of heavy infection, yet, numbered a lot, and individual chemotherapy has not been going on. In conclusion, it was suggested that the number of reinfected inhabitants among those under mass chemotherapy were numerous. Accordingly, the reinforcement of health education should be followed with mass chemotherapy. The facts of high infection rate exemplified by 65% and high number of those above the category of heavy infection in Samrangjin area say that reevaluation of dosage, number of medication and intervals should be necessarily made.

• Journal of Technology Innovation
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• v.11 no.1
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• pp.79-97
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• 2003

R&D expenditure of Korean firms has been increasing drastically since 1980 and occupied 84% of total R&D expenditure in 1994. After 1994, however, the growth rate of industry R&D expenditure has dropped below single digit. R&D concentration rate of upper 20 companies declined from 61.9% in 1999 to 49.8% in 2001. The technology trade balance has diverged by 2.8 billion dollars in 2000 compared to around 0.3 billion dollars in 1985. We find several reasons on declining the industry R&D growth rate in Korea. First, we carefully say there might be an crowding out effect in increasing government R&D investment from Granger causality test between industry R&D and government R&D. Second, the decreasing benefit of tax credit since 1992 on industry R&D expenditure has caused the decrease of industry R&D growth rate. Third, the type of R&D cost becomes to similar to matured countries type of cost, which means the portion of capital expenditure has been decreased since late of 1980s. Therefore, industry R&D growth rate gets to saturation point. We draw several policy implications from the changing structure of business R&D of Korean company. Firstly, to stimulate industry R&D investment Korean government needs to strengthen tax credit policy. Secondly, to induce foreign direct investment Korean government needs to establish technology infrastructures and high quality of manpower. To utilize foreign technology resources Korean government need to introduce global R&D program executed by foreign scientist as an Project Leader.

• Journal of computational fluids engineering
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• v.16 no.2
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• pp.66-74
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• 2011

The SCR catalyst in coal-fired power plant is eroded by the collision of fly ash on the catalyst surface. However the erosion of SCR catalyst by the collision of fly ash has not been fully studied, especially in terms of fluid dynamics. Hence, in the present study, we focus on the gas and solid flows inside the SCR catalyst duct and their consequent effect on the erosion characteristics. For this purpose, computational fluid dynamics is applied to investigate the two-phase flows and to evaluate the erosion rate for different flow and particle injection conditions. Also, the erosion rate and pressure drop of commonly used square shape are compared with equilateral triangle and hexagon shapes. The pressure drop of SCR catalyst is increased when SCR catalyst surface area per unit volume increases. The erosion rate of SCR catalyst is enhanced when the particle velocity, mass flow rate of particle, particle diameter and cell density of SCR catalyst are increased. From the results, the pressure drop and erosion rate at the catalyst surface can be minimized by reducing cell density of SCR catalyst to decrease particle velocity and number of particle impacts.

• Journal of the Ergonomics Society of Korea
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• v.31 no.1
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• pp.151-156
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• 2012

Objective: In 2010, the rate of injuries and illnesses in the shipbuilding industry was 1.20, about 1.74 times higher than the average of overall industries(0.69). Musculoskeletal disorders(MSDs) became a major problem since 2000 in shipbuilding industry. The purpose of this study was to provide efficient implementation management through evaluating the economic effectiveness of the Musculoskeletal Disorders Prevention Program(MDPP). Successfully implementing the MDPP in the workplace may decrease the risk of MSDs and therefore reduce MSDs related costs. Methods: Occupational accident index (frequency rate, severity rate, and frequency severity indicator), estimated direct costs, and total occupational accident occurrence rate were provided by analysis of MSDs, statistical analysis of MDPP decreed companies, and data analysis of implementation. Results: The study shows the number of MSDs for MDPP decreed companies decreased 76.2% from 2,319 in 2004 to 551 in 2008. Above all, the number of MSDs decreased 78.7% in Shipbuilding industries. Forty companies (85.1%) showed a decreasing tendency and 27.7% of those had an $R^2$ > 0.7. Similar results were found in severity rate and frequency severity indicator. From these results, it appears there are a number of advantages in implementing the MDPP. Conclusion: MDPP effectiveness was demonstrated by analysing implementation and occupational accident index. A more effective and efficient implementation would take into account business sector, size, policy, and organization of the company.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.31 no.4
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• pp.214-224
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• 2020

Objectives: This study aimed to examine the trend in diagnostic prevalence of psychiatric disorders in children and adolescents. Methods: Individuals aged 0-18 years were included in the study based on the National Health Insurance Claims Data. To investigate the trends in diagnosis and diagnostic prevalence of psychiatric disorders reflecting the decrease in the birth rate, data were analyzed from 2010 as a reference year to 2015. Results: The number of patients diagnosed with psychiatric disorder decreased annually, from 23,412 on 2010 to 18,821 on 2015. The most common disorder was hyperkinetic disorder in male and depressive episode in female. Although there was no significant change in overall diagnostic prevalence rate of psychiatric disorders, age groups <10 years and some disorders had significant changes in prevalence rate. This study classified the diagnostic prevalence by age into two unique patterns: group in which the diagnosis rate increases with age and group in which the diagnosis rate peaks at a certain age and then decreases. Conclusion: Diagnostic prevalence of psychiatric disorders was different according to age and sex. These patterns should be reflected in the formulation of policies related to mental health and in medical practice for pediatric patients. It is urgent to identify how these patterns change in young adults.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.4
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• pp.313-318
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• 1990

Forty-two outbred female Sprague-Dawley rats weighing 145 g were used to study the effects of a beta-agonist, cimaterol, on growth, body composition and urinary excretion of 3-methylhistidine (MH) at 3, 6 and 18 d. Cimaterol (CIM) was administered in the feed at 10 mg/kg. The growth promoting effect of CIM was most evident during the initial part of the feeding period, followed by a gradual decrease in the magnitude of the response with no significant effect at 18 d. The action of CIM was confined to skeletal and cardiac muscles with no stimulating effect on other organs. The amount of urine excretion and urinary MH excretion was reduced (p<.01) at 3 d in the CIM group. No difference was found at 6 d, followed by an increased urine excretion (p<.05) and MH excretion (p<.01) at 18 d. An inverse relationship between growth rate and urinary MH excretion suggested that the increased growth rate of CIM-fed rats during the initial part of the feeding period is primarily attributed to the decreased protein degradation rate. It was further suggested that both fractional synthesis rate and fractional degradation rate increased during the later part of the feeding period.

• Journal of the Korean Chemical Society
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• v.13 no.2
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• pp.109-114
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• 1969

Halogen exchange reactions of benzyl halides have been studied in absolute acetone. Rate constants were calculated using an integrated rate expression derived for the reaction involving ion-pair association. The order of nucleophilicity of halide ions in acetone was found to be a reverse of the order in 90% aqueous enthanol solvent. This was interpreted by means of HSAB principle and solvation of halide ions. Net increase in rate of reaction in acetone compared with the rate in protic solvent resulted from large increase in ${\Delta}S^\neq$ rather than decrease in ${\Delta}H^\neq$. The solvation of the transition state also contribute to the net increase in rate.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.5
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• pp.238-246
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• 2002

Utilities are trying to install the equipment of high quality to avoid deterioration of supply reliability. In addition, many sectionalizing switches which can decrease the total outage value for a fault are installed for the same reason. Therefore, utilities are interested in stun dards and criteria for installing switches to optimize the total cost on distribution systems. The affect of sectionalizing switches installed on distribution feeder is gradually decreased because the failure rate on distribution feeder is decreased. Also the automation for distribution systems is widely applied for the efficient operation. Therefore, the renewal for installation standards of sectionalizing switches Is required to reflect the current operation situation. The variable data is used to consider the KEPCO's real situation of distribution feeder as follows; the feeder capacity, connecting rate, feeder length, failure rate of distribution feeder, the failure rate of switches, perception time of feeder fault, the restoration time for a faulted section, the transfer time to other feeders, and the switching time. In this study, We propose equations which can determine the number of sectionalizing switches for minimizing the outage and switch installation cost.

• Journal of the Korea Institute of Building Construction
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• v.7 no.4
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• pp.139-144
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• 2007

The purpose of this study is to analyze concrete characteristics by admixing agent and additive contents according to the change of unit-water to identify its effect on compressive strength. First of all, as for flesh concrete, overall unit-water showed a tendency to decrease as component inclusion rate of admixing agent was increased. In addition, air content showed a tendency to increase by increasing WR, WB, NP series admixing agent contents, on the other hand, the change of air content was gentle by around $1.5{\pm}0.5%$ for S, T, M series agents. Bulk density showed an inverse proportion to the change of air content. As for hardened concrete, expression rate of 3-day age compressive strength was generally decreased for S, T, WR, WB, NP, M series admixing agent component. Also, expression rate of 7-day age compressive strength showed an excellent record for S, M series agents, and expression rate of 28-day age compressive strength showed a tendency to increase more than plain on the whole.

• Water for future
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• v.9 no.2
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• pp.67-75
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• 1976

With 9 existng reservoirs selected in the Sab-Gyo River Basin, the sedimentation of the reservoirs has been calculated by comparing the present capacity with the original value, which revealed its reduced reservoirs capacity. The reservoirs has a total drainage area of 6,792 ha, with a total capacity of 1,204.09 ha-m, and are short of water supply due to reduction of reservoirs capacity. Annual sedimention in the reservcire is relation to the drainage area, the mean of annual rain fall, and the slop of drainage area. The results of obtained from the investigation are summarized as follow; (1) A sediment deposition rate is very high, being about $9.19{m}^3/ha$ of drainage area, and resulting in the average decrease of reservoir capacity by 19.1%. This high rate of deposition could be mainly attributed to the serve denvdation of forests due to disor derly cuttings of tree. (2) An average unit storage of 415.8mm as the time of initial construation is decreesed to 315.59mm at present, as resultting, we could'nt supply water at 566.24ha. (3) A sediment deposition rate as a relation to the capacity of unit drainage area is as follow; $Qs=1.43 (c/a)^{0.531}$ (4) A sediment deposition rate as a relation to the mean of annval rainfall is as follow; $Qs=672.61 p^{0.024}$ (5) A sediment deposition rate as a relation to the mean slop of drainage area is follow; $Qs=267.21 S^{0.597}$