• Korean Journal of Medicinal Crop Science
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• v.6 no.2
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• pp.154-159
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• 1998

This experiment was conducted to investigate the effects of plant age on germination and distribution of seed specific gravity and to find a reason of low germination rate in seeds harvested from young plants, which could be valuable information for the improvement of seed germination in Bupleurum falcatum L. The germination rates of Korean native cultivar were 35% and 4% higher in 1-year-and 2-year-old plants, respectively, than Misshimasaiko (三鳥柴胡) and showed no significant difference between 1- and 2-year-old plants. However, in Misshimasaiko, seed germination rates of 1-year-old plants were $22.7{\sim}23.0%$ lower than those of $2{\sim}3-year-old$ plants. The relative frequency of seeds over 1.00 specific gravity in Misshimasaiko was $33{\sim}34%$ higher in $2{\sim}3-year-old$ plants compared to 52% of 1-year-old plant, but no difference was found between plant ages in Korean native cultivar. Considering varietal difference, the germination rate of seeds with the same specific gravity was not affected by plant age in Korean native cultivar, but in Misshimasaiko it was greatly different between 1-year-old $(5.0{\sim}17.5%)$ and $2{\sim}3-year-old$ plants $(22.5{\sim}55.0)%$. From these results, it was assumed that differences in germination rate among seeds from different plant ages were caused not only by seed specific gravity but also by some other factors.

• The Korean Journal of Ecology
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• v.24 no.6
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• pp.371-376
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• 2001

The rate of soil respiration to varying stand ages was studied in four Robinia pseudoacacia stands(18-, 23-, 28- and 35-year old) throughout one year from September 1998 to August 1999. Soil temperatures showed a pronounced seasonal pattern, in contrast to soil moisture. The highest rate of soil respiration was generally found in August when soil temperatures were the highest, and the lowest in January. The daily rate of soil respiration amounted to 5.51($g\;CO_2{\cdot}m^{-2}{\cdot}day^{-1}$) for 18-year old stand, 5.28 for 23-year old stand, 8.29 for 28-year stand, and 2.67 for 35-year old black locust stand, respectively. The $Q_{10}$ values were ranged between 1.63 and 1.66, averaging 1.65 for the R. pseudoaca'cia stands. The results indicate significant correlation between soil temperature and soil respiration for all four stands(r=0.96 to 0.97). Among the study stands, the annual rate of soil respiration was the highest ($3.03kg\;CO_2{\cdot}m^{-2}{\cdot}yr^{-1}$) for 28-year old stand.

• Journal of Ginseng Research
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• v.14 no.1
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• pp.44-49
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• 1990

Effect of liming material application on the prevention or cure of Mn toxicity symptoms including marginal leaf chlorosis in 3-year-old ginseng plants grown in acidic soils were investigated. It was found that the ratio of Fe to Mn was above about 0.5 and the ratio of Mn to Fe was below about 2.00 in 4-year old ginseng leaves when liming materials were applied in field experiments. It was apparent that the occurrence of marginal leaf chlorosis was decreasing affected by application of Ca, Mg and Fe. The appearance of marginal leaf chlorosis was decreased to about 78 percent in 4-year-old ginseng and to about 69 percent in 5-year-old ginseng, and then the fresh root weight was increased up to 66 percent in 4-year ginseng plants.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.4
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• pp.494-506
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• 2012

The purpose of this study was to analyse 3, 4, 5-year-old children's private speech according to their age and task characteristics (structured task vs. unstructured task). In order to achieve the goal, the main effect of age, characteristic of tasks and interaction effect were considered among age and characteristic of tasks on preschool children's private speech. The subjects were each 30 3, 4, 5-year-olds from preschool in Busan, South Korea. The structured task was puzzle task and the unstructured task was drawing task from TCT-DP. The data was analyzed by repeated measurement two way ANOVA: 3(age) ${\times}$ 2((characteristic of task). As a result, firstly, total private speech of 4-year-old was higher than 3-year-old, 5-year-old in both tasks, and total private speech of 5-year-old was higher than 3-year-old in both tasks. Secondly, the task-irrelevant private speech was not affected by main effect of age and characteristic of task and interaction effect between age and characteristic of task. Thirdly, the task-relevant private speech was received both main effects and interaction effects between age and characteristic of task. Finally, the external manifestation of inner speech were not received effect of age but received effect of characteristic of task, and received interaction effect between age and characteristic of task. The results of this study imply that characteristic of task is an important factor inducing children's private speech.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1981.05a
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• pp.5.1-5
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• 1981

We have recently removed five interesting foreign bodies successfully. Case 1. A broken tracheostomy outer cannular tube in the right main bronchus of a 7 year old boy. Case 2. An acupuncture needle in the trachea of a fifty-one year old man. Case 3. A fish hook with thread in the second isthmus of esophagus of a 10 month old girl. Case 4. An opened safety pin (sharp point toward cephalad) in the third isthmus of esophagus of a sixteen year old boy. Case 5. A big lead bullet which went through soft tissue below right mastoid tip and lodged at the mid-point between right mastoid process and foramen magnum(skull base) of a twenty year old boy, was removed surgically uneventfully.

• Journal of Ginseng Research
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• v.25 no.2
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• pp.101-105
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• 2001

Identification of the age of ginseng root is very important in commercial market as well as in research field. However, any criterion abut it has not been clearly established yet. We studied to find a clear morphological key for identification of ginseng root\\`s age using the histochemical staining method. Fresh sections of 3, 4, 5, and 6 year old roots were stained with 1% nile blue, observed under the light microscopy, and compared each other. The number of secretory duct layers(SDL) is a useful key to confirm the age of ginseng root as follow; three-year-old root has two, four-year-old one has three, fie-year-old one has four, and six-year-old one has five resin duct layers on each cortical region of roots. Secretory ducts are thought to be formed by the vascular cambium every year. Unlike the surrounding parenchyma cells, secretory epithelial cells lack starch grains in the cytoplasm.

• Journal of the Korea Society of Computer and Information
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• v.24 no.2
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• pp.179-184
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• 2019

As the tendency of children's overdependence on smart phones increased, it was obligatory to carry out preventive education more than once a year in kindergarten and day care center, but there is no specific guidance on contents and method of preventive education. This is due to the lack of prior studies on the actual use of smartphones and the influence variables of infants and young children. The purpose of this study was to investigate the effects of use time, frequency of use, and sociological background variables on the actual situation of smartphone usage and overdependency on smartphone among 3-5 year old children nationwide. For the analysis, the frequency of the use of smartphone for 3-5 year old children was analyzed by frequency analysis, and the influence variables were correlated and multiple regression analysis. Research shows that smartphone overdependence of 3-5 year old children have an influence on the use time and frequency of use. The results should include content that restricts the use time and frequency of use of smartphones and prevention education programs for 3-5 year olds and young children. Suggesting a need for a transition to the educational method used.

• Korean Journal of Child Studies
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• v.24 no.1
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• pp.61-76
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• 2003

This study investigated children's cognition of physically impossible televised events by age and types of tasks. The 67 subjects were 3-, 5-, and 7-year-old children from 1 day care center and 1 elementary school in Seoul. Children's responses were taped and transcribed. Cognition about the events were measured by recognition of impossibility, possibility of replication, and reasons for the possibility of replication of the events. Data were analysed by ANOVA(repeated measure) and $Scheff{\acute{e}}$ test. Children's cognitions about the events varied by age groups. Three-year-old children's recognition of the 3 tasks was different from that of the 5-and 7-year-old children; while 3-year-olds interpreted the events on TV as real, 5- and 7-year-olds considered them to be unreal.

• Journal of Ginseng Research
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• v.13 no.1
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• pp.84-91
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• 1989

This study was conducted to Investigate the effects of physico-chemical soil properties on the growth and yield of ginseng. 1 In the field survey, the yields of 6 year old ginseng were 2.46 Kg/3.3$m^2$, 2.13 Kg/3.3$m^2$, 1.44 Kg/3.3 $m^2$ in clay loam, loam and sandy loam soils, respectively 2. The missing plant rate for il year old ginseng were 33.6% and 51.6% in clay loam and sandy loam soils, respectively : the stem length and stem diameter of ginseng plants in sandy loam soil were smaller than those in clay loam soil. 3. Soil aggregation and porosity we're slightly higher in 6 year old ginseng fields than in 2 year ones. 4. Inorganic-N increased in 2 year and 3 year old ginseng fields reaching up to 100-120ppm, however it 1 decreased to 75 ppm, 34 ppm and 25 ppm in 4, 5 and 6 year old ginseng fields, respectively, It varied 1 more greatly in sandy loam soil than in clay loam. 5. The $P_2O_5$, K, Ca, and Mg contents differed little with plant age. Sandy loam had high N and $P_2O_5$ contents but low cation contents. 6. The yield of 6 year old ginseng fields were significantly correlated with clay contents and porosity. The missing Plant rate of 6 year old ginseng had a positive correlations with sand. and N contents.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.93-96
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• 2007

Research was taken its place in Dong wun elementary school in Gwang ju city. Subject ages were somewhere around 9 to 13. Among total number of 1,196, subjects with emmetropia were 384 people (32.1%), with 22.56% of 9 year old students, 16.01% of 10 year old student, 36.45% of 12 year old student, 39.11% of 13 year old. When age increases, the rate of emmetropia increase as well. Gender dependence of emmetropia rato was 31.07% for boys and 33.33% for girls, which proves girls with higher emmetropia ratio than boys. Among subjects with binocular vision acuity lower than 0.7, those require spectacles, only 37.5% of 9 years old students, 30.3% of 10 year old students, 44.64% of 12 year old students, and 30% of 9 year old students were wearing glasses. It shows that spectacle-wearing ratio is very low in spite of visual acuty lower than 0.7.