• Korean Journal of Veterinary Research
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• v.11 no.1
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• pp.69-81
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• 1971

The effects of n-hexane and tetrachlorodiphenyl on the growth rate, the blood picture and histopathological change induced were observed in chicken. A total of 350 chicken were fed various daily dosages of n-hexane and tetrachlorodiphenyl for the experimental period of 60 days. The results obtained were as follows. 1. The growth rate of chicken in the group fed 100 ppm of tetrachlorodiphenyl was reduced (p<0.05). However no significant results were observed in the other dosage groups. 2. The reduction of the growth rate was found only in the liver and the kidney but not found in the other orgns. 3. No significant results were found in the number of erythrocytes and hematocrit value. However, the number of leukcocytes of chicken in the group fed 100 ppm of tetrachlorodiphenyl was significantly low. 4. In both n-hexane and tetrachlorodiphenyl groups, the number of lymphocytes was found to decrease but the number of basophiles and eosinophiles were found to increase (p<0.05). 5. All the chicken fed 300 ppm of tetrachlorodiphenyl died between 7th and 9th days. 6. Fatty change of hepatic cells and cloudy swelling of epithelia of renal tubules were found in the group fed 0.5 ml of n-hexane. However, in the group fed more the 100 ppm, fatty change of hepatic cells was followed by necrosis and comparatively severe cloudy swelling was found in epithelia of renal tubules.

• Bulletin of the Korean Chemical Society
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• v.19 no.7
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• pp.776-779
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• 1998

Second-order rate constants have been measured spectrophotometrically for the addition reaction of a series of alicyclic amines to 3-butyn-2-one to yield their respective enamines at 25.0 'C. The reactivity of the amines increases with increasing the basicity of the amines. However, the Bronsted-type plot obtained exhibits a downward curvature as the basicity of the amines increases, i.e. βnuc decreases from 0.3 for low basic amines (pKa < 9) and to 0.1 for highly basic amines (pKa > 9). Such a curvature in the Bronsted-type plot is clearly indicative of a change in the reaction mechanism or transition state structure. From the corresponding reactions run in D2O, the magnitude of kinetic isotope effect (KIE) has been calculated to be about 0.8 for highly basic amines and 1.21 for weakly basic amines. The difference in the magnitude of KIE also supports a change in the reaction mechanism or transition state structure upon changing the basicity of the amines. Furthermore, the small KIE clearly suggests that H+ transfer is not involved in the rate-determining step, i.e. the addition reaction is considered to proceed via a stepwise mechanism in which the attack of the amines to the acetylene is the rate-determining step. The curvature in the Bronsted-type plot has been attributed to a change in the degree of bond formation between the amine and the acetylene.

• Journal of Korean Medicine for Obesity Research
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• v.2 no.1
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• pp.73-82
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• 2002

Objectives: The purpose of this study is to investigate the effect of the aerobic exercise and weight training combined with VLCD(very low calorie diet) and chegameuyiin-tang(體減薏苡仁湯) on the change of the body composition during 15 days of hospitalization treatment. Methods: Twenty four female obese patients were observed. Exercise regimen was composed with aerobic exercise and weight training program, and the intensity of aerobic exercise were 50% HRmax(maximal heart rate) twice time a day and weight training were 50% 1RM(one repetition maximum) a day. All subjects diet regimen was VLCD of 600kcal/day. Results & Conclusions. 1. There was no significant difference between the aerobic exercise and the weight training groups in the change of body weight, fat mass, and percent body fat, waist-hip ratio, body mass index and resting metabolic rate. 2. In the comparison of the change rate of FFM(fat free mass), weight training group preserved FFM better than aerobic-exercise-only-group with no statistical significance.

• Human Ecology Research
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• v.59 no.3
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• pp.341-351
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• 2021

The purpose of this study was to examine the longitudinal relationships between Korean adolescents'mobile phone dependency, trajectories of depression, and self-regulated learning abilities. To achieve these goals, structural equation modeling analysis was conducted, using the 3rd, 5th and 7th wave of the data on 4th graders taken from the Korean Children and Youth Panel Survey. The results can be summarized as follows. First, growth-curve longitudinal analysis indicates that depression in 6th through 10th grade has increased. Second, mobile phone dependency among adolescents at 6th grade has a significant effect on both the initial value and the rate of change in depression. Also, the initial value and the rate of change in depression have significant relationships with mobile phone dependency at 10th grade. Moreover, both increased levels of mobile phone dependency and the rate of change in depression significantly influence adolescents'self-regulated learning abilities at 10th grade. Based on a longitudinal data set, these findings demonstrate the causal relationships between Korean adolescents'trajectories of depression and their mobile phone dependency. The findings also provide a comprehensive framework with implications for adolescents'development through an understanding of the relationships between adolescents'depression and mobile phone dependency, which impact their self-regulated learning abilities.

• Korea journal of population studies
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• v.31 no.1
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• pp.27-54
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• 2008

The purpose of this study is to analyze the effect of policy boosting fertility and labor participation rate on potential GDP growth rate. To do this, we employ a growth accounting approach, which decomposes per capita GDP into two parts. The first one is the change of dependency ratio and the other is the change of labor input. The labor input is again decomposed into the qualitative and quantitative parts. The quantitative part considers the change of labor participation rate and working time. The qualitative aspects is based on the trend of productivity of labor. From the scenarios of NSO(National Statistics Office), the effect of the fertility-raising policy on per capita potential GDP growth rate is calculated and projected to the year of 2050. We also forecast the policy effect inducing high labor participating rate of female labor and beyond 55-year old labor. The baseline results show that the per capita GDP growth rate will show mid 4% to the year of 2010, gradually declining to 3.94% by 2020, 3.03% by 2030, 2.41% by 2040. The high fertility rate scenario will not have effects on the potential growth by 2030, but show 0.10%p higher per capita GDP growth rate than that of baseline scenario result. By the high female labor participation policy, the per capita GDP growth rate will reach 0.04%p higher per capita GDP growth rate than that of baseline scenario. Based on the results of this paper, we conclude that the quantitative labor input cannot solely account for the trend decline of potential GDP, and the qualitative aspect, like labor productivity, is much more important element to sustain and boots the economic growth.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.3
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• pp.192-200
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• 2002

There is a volume change between the sediments and the dredged materials because the dredged materials is fully disturbed by the dredger and settled in the basin from the stabilized condition. The volume of the dredged materials is also affected by the coagulants and flocculants (hereafter C & F) which was used to speed up the settling of the suspended solids. In this study, the volume change of the dredged materials is analysed in detail due to the injection amount of the C & F. The dredged materials were sampled in the lagoon located in the East coastal zone, and the volume change of the samples is quantitatively analysed by the laboratory test due to the change of the clay content and the amount of the C & F. The optimal amounts of the C & F is determined by showing the minimal volume change due to C & F injection. From the experimental results, the volume of the dredged materials is increased 1.68 times on an average and the volume change rate is slightly increased, i.e., negligible, as the clay content increase in the case of the C & F injection.

• The KIPS Transactions:PartD
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• v.17D no.4
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• pp.271-282
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• 2010

Insufficient requirement management accounts for 54% ofunsuccessful software development projects and 22% of insufficient requirement management comes from requirement change management. Hence, requirement management activities are important to reduce failure rates and a tracing method is suggested as the major factor in requirements change management. A traceability table is easy to use because of its legibility accurate tracing. However, traceability tables of existing studies have failed to concretely suggest method of change management and effect of traceability. Also, studies of methods to estimate change impact is complex. Hence, this study suggests how to use a traceability table to manage changes in requirements. Together, in comparison to existing studies, this study suggests easier methods to estimate change rate and change impact. Also Fifteen projects were sampled to test the hypothesis that traceability table influences the success of projects and that it decreases the failure rate that comes from the insufficient requirements management.

• Journal of Forest and Environmental Science
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• v.39 no.3
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• pp.167-179
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• 2023

The extent of change in the Land use/Land cover (LULC) of Okomu National Park (ONP) and fringe communities was evaluated. High resolution Landsat imagery was used to identify the major vegetation cover/land use systems and changes around the national park and fringe communities while field visits/ground truthing, involving the collection of coordinates of the locations was carried out to ascertain the various land cover/land use types identified on the images, and the extent of change over three-time series (2000, 2010 and 2020). The change detection was analyzed using area calculation, change detection by nature and normalized difference vegetation index (NDVI). The result of the classification and analysis of the LULC Change of ONP and fringe communities revealed an alarming rate of encroachment into the protected area. All the classification features analyzed had notable changes from 2000-2020. The forest, which was the dominant LULC feature in 2000, covering about 66.19% of the area reduced drastically to 36.12% in 2020. Agricultural land increased from 6.14% in 2000 to 34.06% in 2020 while vegetation (degraded land) increased from 27.18% in 2000 to 38.89% in 2020. The magnitude of the change in ONP and surroundings showed the forest lost -247.136 km² (50.01%) to other land cover classes with annual rate change of 10%, implying that 10% of forest land was lost annually in the area for 20 years. The NDVI classification values of 2020 indicate that the increase in medium (399.62 km² ) and secondary high (210.17 km² ) vegetation classes which drastically reduced the size of the high (38.07 km² ) vegetation class. Consequent disappearance of the high forests of Okomu is inevitable if this trend of exploitation is not checked. It is pertinent to explore other forest management strategies involving community participation.

• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.93-101
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• 2003

The extinction of unsteady diffusion flame was experimentally studied in an opposing jet counterflow burner using diluted methane. The stabilized flame was perturbed by linearly varying velocity change that was generated by pistons installed on both sides of the air and fuel stream. As the results, the extinction of unsteady flame is dependent not only on the history of unsteadiness, but also on the initial condition. We found that there are several unsteady effects on the flame extinction. First, the extinction strain rates of unsteady cases are extended well beyond steady state extinction limits. Second, as the slope of the strain rate change increases, the unsteady extinction strain rate becomes larger. Third, the extension of unsteady extinction strain rate becomes smaller as the initial strain rate increases. We also found that the extension of the extinction limit mainly results from the unsteady response of the reaction zone because there is no retardation effect of a mixing layer for our experimental condition.

• 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.