• 대한치과교정학회지
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• 제11권2호
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• pp.125-134
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• 1981

To study the calcification of second molars in skeletal class II malocclusion, the author examined cephalograms, orthopantomograms, periapical films of 391 children from 7y 0m to 15y 11 m years old who had skeletal class II malocclusion, and observed the difference in the calcification stage between upper and lower second molars. The result s are as follows. 1. The mean ages of crown completion of upper and lower second molars are $8.7{\pm}1.75$, $8.8{\pm}1.13$ in boys, and $8.4{\pm}0.81$, $8.5{\pm}0.91$ in girls. 2. The mean ages of root completion of upper and lower second molars are $14.0{\pm}1.09,\;14.5{\pm}0.52$ in boys, and $13.7{\pm}1.15,\;13.8{\pm}1.18$ in girls. 3. The calcification stages of upper second molars are more advanced than those of lower second molars at $5\%$ level in both sexes.

• 한국환경보건학회지
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• 제23권3호
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• pp.66-71
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• 1997

To investigate the effect of several factors on serum lipids in maternal and infants umbilical cord blood, 111 cases of newborn infants and women delivered of a child who had delivered at hospital located in Chung-Ju city from Feb. 1, 1996 to Aug. 31, 1996 were studied. The gestational ages of cases were 37 to 42 weeks and the average maternal ages were 28.1$\pm$4.25 years old without any other medical or obstetric problems. No relationships between maternal consumption of coffee and maternal serum lipid levels were observed. However, serum total cholesterol and LDL-cholesterol levels in infants'umbilical cord were significantly increased in proportion to increasing maternal consumption of coffee. The other factors such as alcohol drinking habits and residency affected maternal serum lipid levels and not serum lipid levels in infants' umbilical cord. Delivery frequency showed very little or no effects on serum lipid levels in both maternal blood and infant's umbilical cord blood. In conclusion, maternal consumption of coffee significantly correlated with increasement of serum lipid levels in infants'umbilical cord.

• Journal of Ecology and Environment
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• 제34권3호
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• pp.251-257
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• 2011

The purpose of this study was to investigate the acclimation responses of Tamarix chinensis to cold stress. We evaluated the acclimation responses by measuring biomass, daily elongation rate, chlorophyll content, and total soluble carbohydrate content. The plant samples comprised leaves from seedlings of 2 different ages (8 and 12 weeks); the leaves were collected 0, 2, and 4 weeks after cold treatment. We found that the cold-treated samples showed reduced daily elongation rates and chlorophyll content. Further, these samples showed more than 8-fold increase in the total soluble carbohydrate content. However, the seedling ages did not have a significant influence on the growth of cold-treated seedlings. On the basis of these findings, we can conclude that T. chinensis seedlings aged less than 1 year old show acclimation to cold stress by accumulating soluble carbohydrates. This study may help us understand how T. chinensis seedlings acclimatize to their first cold season.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.407-410
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• 1999

The 5 types of cement mortar was immersed in the various chemical solutions for 400 days and then the compressive strength and the length change were measured to consider the chemical resistance at required ages. Due to the effect of flyashe and GGBF slag, the compressive strength of blended cement mortar was higher than that of portland cement mortar at long ages. According to the result of length change, the mineral admixture in blended cement had an indluence on reducing the amount of C3A, the cause of making concrete expand, and it made the formation of cements mortar denser so that the length change was much smaller than that of the portland cement mortar. However, the OPC mortar immersed in Na2SO4 solution for 180 days shows 4 times bigger length change chante than the blended cement mortar.

• 대한한방내과학회지
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• 제19권2호
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• pp.208-218
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• 1998

To clarify the activating effects of Buthus martensi Karsch on immunological function, its effect on primary and secondary antibodies production in mice of various ages was investigated. Buthus martensi Karsch increased the number of both antibody producing cells(anti-IgM and anti-IgG producing plaque forming cells, PFC) and phagocytic activity of peritoneal macrophage. Futhermore, these phenomena were significantly increased with aging in mice. Buthus martensi Karsch also increased natural killer cell activity concerning to cancer immunology. These results suggest that Buthus martensi Karsch markedly increases the reduced activity in the elderly and activates the immune response in senescence mice.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.571-574
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• 2000

When fresh concrete is exposed to low temperature, the concrete may suffer from the frost damage at early ages and the strength development may be delayed. To solve such problems of cold weather concreting admixtures called agent for enduring cold climate are developed to prevent the fresh concrete from being frozen at early ages. In this study, the experiments are carried out on several kinds of agent for enduring cold climate to present their performance. According to experimental results, most kinds of agent for enduring cold climate show the strength development in the range $-5^{\circ}C$ of curing temperature, it tends to be delayed at long term maturity without agents for enduring cold climate. while it gains high strength maturity when agents for enduring cold climate is applied.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.273-276
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• 2003

The non-evaporable water and calcium hydroxides were measured by TG/DTA for studying the temperature effect on hydration of concrete mixture. The experimental parameters introduced in this study were the curing temperatures, ages and W/C ratios. The mixing temperature was also controlled to improve the efficiency of experimental work. While the mixture cured at high temperature showed the large quantity of non-evaporable water and calcium hydroxides at early age, the production rate of these hydration products was decreased as increasing the curing age, and the quantity of hydration product became smaller than that of the corresponding mixture cured at lower temperature at later age.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.527-532
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• 2003

When fresh concrete is exposed to sufficiently low temperature, the free water in the concrete is cooled below its freezing point and transforms into ice, which causes decrease in compressive strength of concrete. Of the many influencing factors on the loss of compressive strength, the age of concrete at the beginning of freezing, water-cement ratio, and cement-type are significantly important. The objective of this study is to examine how the these factors affect the compressive strength of concrete frozen at early ages. The results from the tests showed that as age at the beginning of freezing is delayed and water-cement ratio is low, the loss of compressive strength decreases. In addition, concrete made with high-early-strength cement is less susceptible to frost damage than concrete made with ordinary portland cement.

• Journal of Oral Medicine and Pain
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• 제6권1호
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• pp.57-82
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• 1981

The author had collected the full mouth stone model of 277 persons from 20 ages to 60 ages and studied the attrition pattern of posterior teeth paying attention to the teeth cusps on the stone model. All of the attrition patterns were classified by age, sex and analyzed. The results are followings : 1. Attrition patterns of posterior teeth were divided into 64 forms.(expept 3rd molar) 2. There was no significant difference between right & left. 3. Generally early attrition pattern of younger age and late attriction pattern of older age were more prominent in men being compared with sexual difference. 4. Being compared with age group, early attrition pattern showed decreasing tendency and late attrition pattern showed increasing tendency by aging.

• 한국주거학회논문집
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• 제12권2호
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• pp.45-54
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• 2001

The purpose of this research was to analyze the correlation between the Apartment Purchase Price Decision Factor and Amenity decision Factor with cognition of the Consumer. The result are as follows; 1. The correlation coefficient between the Apartment Price Decision Factor and Amenity decision Factor with cognition of the Consumer was 0.587. 2. The ranking of the purchase price factor which it prefers were analyzed orientation > sunlight > view > the rising price expectation > natural environment etc. And the ranking of the amenity were analyzed orientation > natural environment > view > sunlight > noise etc. 3. Consumer group was classified the location, sex, year of ages and unit scale. The rank correlation coefficient of (the significant was below 0.05) sex was 0.617~0.644, year of ages was 0.62~0.771 and unit scale was 0.762~0.852. This research proved the fact that the amenity correlated with the apartment purchase price decision factor, so amenity contained an economic value. And this result will be used in decision-making-process of apartment construction.