• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.113-119
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• 2006

Recently, the ground injection method using water glasses as one of the main resources and the products of these constructions have basic problems in terms of the method of constructions for the permanent foundation reinforcement and stopping leakage of water because they have some serious problems such as durability, compressive strength, injectant eluviation and so forth even though they are still used to stop leakage of water in the temporary structures. The purpose of this study is to demonstrate the strength characteristic and environment friendliness of NDS method by unconfined compressive strenth test, permeability test, length change test, leaching test, and assessment of environmental impact in comparison water glass type material. The test results show that NDS method has significant improvement of strength, permeability, volume change, and leaching. An assessment of environmental impact also demonstrates that the NDS material is environmentally friendly.

• Journal of the Korean GEO-environmental Society
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• v.12 no.10
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• pp.5-12
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• 2011

Recently, NDS(Natural and Durable Stabilizer)method and other similar methods are composed of inorganic accelerating agent and the ultra-super fine cement have been studied as the ground improvement material in Korea. However, in the existing research, the chemical changing process of NDS in the strength development mechanism with the elapsed curing time and the principles of strength development did not give an explanation. For the popularization of the inorganic grout material, it determined that the mechanism verifying of the curing process had to be clearly preceded. Therefore, unconfined compression test, SEM and XRD analysis were performed by the elapsed curing time and were analyzed. In addition, the same trial for SGR method, that is the representative example of the water glass grout material, was selected as comparative target in order to distinguish properties of NDS more clearly. The result of experiment, the strength development mechanism of NDS could be investigated through the close correlation of the unconfined compression strength - SEM - XRD analysis, and excellence of a performance was confirmed.

• Journal of Life Science
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• v.15 no.1 s.68
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• pp.80-86
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• 2005

To achieve the purpose of this study, forty-eight male Sprague-Dawley rats were assigned to control and three endurance exercise group. 36 rats were forced to exercise according to exercise intensity for 8 weeks and 12 rats were untrained for control group. Cardiac cytosol was extracted from cardiac tissue and cardiac mitochondria was purified from the cytosol. Purified mitochondria were separated into four fraction: inner membrane, outer membrane inter membrane space and matrix. The changes of cytosolic and mitochondrial LDH isozymes activity were measure. Relative activity $(\%)$ of cytosol for low and control group showed the following order of prevalence $AB_3>A_2B_2>B_4>A_3B>A_4$ for moderate and high group : $AB_3>B_4>A_2B_2>A_3B>A_4$. Outer membrane for low group showed $AB_3>B_4>A_2B_2$, for moderate group:$ B_4>AB_3>A_2B_2$, for high and control group: $B_4>A_3B$. Inter membrane space for low, moderate and high group showed $B_4>AB_3>A_2B_2>A_3B>A_4$, for control group: $B_4>A_3B>AB_3>A_2B_2>A_4$. Inner membrane for all group showed $B_4>AB_3>A_2B_2>A_3B>A_4$. Matrix for control, low, moderate and high group showed $B_4>AB_3>A_2B_2>A_3B>A_4$. These results suggest that long term exercise intensity effect on cardiac tissue cytosolic and mitochondrial activity and $A_4,\;A_3B,\;A_2B_2,\;AB_3\;and\;B_4$ isozymes were found entirely in mitochondrial fraction.

• Journal of the Korean Geosynthetics Society
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• v.8 no.3
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• pp.25-34
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• 2009

Determination of design parameters of composite ground including colluvial soil layer is far difficult because the maximum particle size of such a soil is remarkably large and particle distribution may vary from area to area. The stress-strain behavior of colluvial soils is in fact dependent upon the engineering characteristics at the boundary between coarse and fine materials. However, strength parameters are in general determined based on the characteristics of fine material, which causes an underestimation of such parameters. In this study, strength parameters of colluvial soil are evaluated by means of BIMROCK model curve. In addition, limit equilibrium analysis is carried out to verify the rational shear strength evaluation.

• Korean Journal of Childcare and Education
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• v.6 no.1
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• pp.67-93
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• 2010

The purpose of the present study was to examine how 25~36-month-old toddlers' temperament, mother's rearing attitude, teacher interaction relates to their language abilities and to analyze the predictive power of these variables in predicting language ability. The subjects were 206 toddlers, 206 mothers and 38 class teachers at child care center in G metropolitan city. The collected data were analyzed using Pearson's correlation analysis and stepwise multiple regression analysis on SPSS program. The results of this study were as follow. First, there was a significant relationship between mother's rearing attitude, teacher interaction and toddlers language abilities. However, toddlers' temperament showed no significant correlations with toddlers language abilities. Second, teacher's positive attitude was the best predictor of toddlers language abilities. Toddlers' reactivity and mother's rational guidance were also predictors of toddlers' language abilities.

• Korean Journal of Childcare and Education
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• v.12 no.1
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• pp.1-17
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• 2016

The objective of the study is to find out the effects of toddler's temperament and mother's parenting behavior on the development of vocabulary ability. The study was conducted with 299 infants between the ages of 18 and 24 months and their mothers in 47 day care centers in I city, Jeollabukdo. The results of the study are as follows. First, according to the correlation between infant's temperament and vocabulary based on the composition of temperament, approach-avoidance, adaptability, and mood showed a negative correlation with receptive and expressive vocabulary, and response intensity showed a positive correlation with receptive vocabulary. Second, according to the relation between mother's parenting behavior and infant's vocabulary ability based on the sub-factors of mother's parenting behavior, instructional parenting behavior and setting-limits parenting behavior showed a positive correlation with receptive and expressive vocabulary. Third, according to the effects of infant's temperament and mother's parenting behavior on the development of infant's vocabulary ability, as for the understanding of vocabulary, the explanation power of approach-avoidance is the highest, followed by instructional parenting behavior, response intensity, and mood. As for expressive vocabulary, the explanation power of instructional parenting behavior is the highest, followed by mood, response intensity and activity. In the development of infant's vocabulary ability, it was found that receptive vocabulary was affected the most by approach-avoidance, and expressive vocabulary was affected the most by instructional parenting behavior. Mothers will have to have interrelation skills suitable for temperament for the development of infant's receptive vocabulary, and have parenting behavior expressing the traits of things and events for the development of expressive vocabulary.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.3
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• pp.263-278
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• 2022

This paper contains experimental study for the development and performance of TBM backfill material with thixotropic properties. The LW backfill material is widely applied to fill the cavity on the back side of the shield TBM excavation, but has disadvantages such as settlement caused by strength reduction, material separation by groundwater, and reduced plasticity. In this paper, laboratory tests and a model test were conducted to assess the performance of inorganic thixotropic backfill material proposed to improve these problems. The results of laboratory tests show that 1 hr-uniaxial compressive strength of ITB was 12 times higher than LW, and the rate of bleeding of 20 hr was 8.3 times lower, and the result of flow table test was more than 27 times higher. This result indicated that the inorganic thixotropic backfill material has superior properties to LW backfill in terms of strength reduction, material separation, and thixotropy. In the model experiment, a model injection device tester was manufactured and the injection performance and filling rate were verified. When material was injected in the water, it was visually checked whether material separation occurred, and it was confirmed that the filling rate was 96% or more. Comparison results with the test of LW and ITB materials was concluded that ITB can reduce the material separation by groundwater and the occurrence of tunnel cavity.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1253-1257
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• 2010

그라우팅은 건설공사에서 지반의 갈라진 틈이나 공동, 공극 등에 적절한 충전재를 압력을 이용하여 주입하는 것으로, 굴착공사 시 누수방지와 불안정한 지반의 보강을 위하여 광범위하게 사용되고 있다. 가장 많이 사용되고 있는 그라우팅 주입재의 재료로는 물유리계를 주재료로 사용하는 약액주입공법이 많이 사용되어지고 있다. 기존의 물유리계 재료를 사용할 경우 발생하는 용출현상 및 강도저하를 보완하기 위하여 가소성을 부과한 무기질계 재료ECG(Eco Clean Grouting)를 사용하여, 강도 및 내구성이 우수하고 주입재의 용출 현상이 발생하지 않아 환경오염 문제가 거의 없는 영구적인 차수 및 보강에 적합한지와 친환경적 특성을 확인한다. 본 연구는 가소성 무기질계 재료인 ECG(Eco Clean Grouting)재료를 사용하여 현재 많이 사용되는 재료인 물유리계 재료로 일축압축강도, 체적변화, 내구성 평가, 투수시험, 어독성 시험, 용탈시험등을 수행하여 비교 분석 하였다. 일축압축 시험결과 재령 28일 강도는 ECG가 물유리재료에 비해 크게 발현되었고, 내화학성시험 결과 ECG의 길이변화율이 거의 없는 것으로 내화학성에서 강점을 보였다.

• Journal of the Korean GEO-environmental Society
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• v.9 no.5
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• pp.37-43
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• 2008

Inorganic injection material, which is one of the ground improvement materials, consists of cement accelerator and inorganic micro particle. The inorganic injection material is known to overcome the major limitations of water glass type improvement materials, which are leaching and accompanying strength loss. The inorganic injection material is superior in durability and strength, and environmentally friendly since leaching is prevented. In this study, the effectiveness and environment-friendliness of the MIS(Micro Injection-process System) using the inorganic injection material is compared to SGR, which uses the water glass. The performed tests were unconfined compression test, chemical resistance test, and fish poison test. The unconfined compression tests showed that the MIS results in 1.7 times higher 28 day strength compared to the SGR. In addition, the strength continually increased with time for the MIS, while it decreased for the SGR. The chemical resistance tests indicated that the rate of change in length using the MIS is 10~25 times smaller than when using the SGR. The fish poison test proved that MIS was more environmentally friendly. The analysis of chemical ingredients of leached showed that the amount of $Cr^{6+}$, Pb and Si leached from the MIS is less compared to the SGR. Accordingly, the MIS grout is more high-strength than existing SGR grout. It is excellent in shortening of construction period, structural stability of foundation and environmentally friendly. So, it is considered that it has not little the problem about groundwater pollution.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.10 no.1
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• pp.43-49
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• 1999

Objectives：One of the most common developmental problems is communication disorder in which a child appears normal in every way but who has failed to begin speaking or speaks very little. A few studies have examined the temperamental characteristics of children with communication disorders. This study was to investigate the temperamental characteristics of Korean children with communication disorders. Methods：The parents of 20 Korean children with communication disorders and the parents of 50 normal control children, the age of both groups ranges from 3 to 7, completed Korean version of Parental Temperamental Questionnaire developed by Thomas and Chess. Children with a pervasive developmental disorder, mental retardation, or speech-motor or sensory deficit were excluded. The scores of each temperamental scale of two groups and the diagnostic clusters of two groups were compared. Results：The children with communication disorders were characterized by lower mood scores and higher intensity of reaction scores than normal controls. The two groups showed no significant correlation in terms of the temperamental diagnostic clusters. Conclusion：This findings suggest the existence of a distinct temperamental profile of the children with communication disorders. Early detection of the profile may be of great value for parents in understanding the developmental characteristics of the children with communication disorders and in providing appropriate parenting approaches.