• Human Ecology Research
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• v.58 no.3
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• pp.429-445
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• 2020

This study developed and validated a 'Parent-child Lexical Interaction Scale for Preschoolers (PLIS-P)'. First, we developed the preliminary scale with 7 factors after reviewing previous literature related to vocabulary and literacy instruction for young children and reflected on feedback from child studies experts and mothers with young children. Subsequently, to validate the scale, the online survey was conducted on mothers with 5-to 6-year-old children who live in Seoul, Gyeonggi, Incheon, Gyeongsang, Chungcheong, Jeolla, Gangwon, and Jeju. Responses from 309 mothers were used to conduct exploratory and confirmatory factor analysis and correlation analysis. The results were as follows. First, the result of exploratory analysis showed that the model with 7 factors was satisfactory: (1) vocabulary exposure, (2) word elaboration, (3) scaffolding, (4) play activity, (5) conventional instruction, (6) word type awareness instruction, (7) word morphology instruction. Second, confirmatory factor analysis confirmed the good fit of the model. Third, the concurrent validity was confirmed by correlation analysis using EC-HOME. Last, the internal consistency reliability of each factor of PLIS-P was also confirmed. This study developed both a theoretical framework of parent-child lexical interaction and a Parent-child Lexical Interaction Scale for Preschoolers. This scale can be used by parents, practitioners, and researchers to acquire knowledge about interaction related to words between Korean parents and young children.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.6
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• pp.755-761
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• 2007

Disinfection performance in clearwell is generally measured by CT, which is expressed by $C{\times}T$. C is represented by disinfection concentration, and T is represented by $T_{10}$ which means 90% contact time in clearwell. In order to improve Disinfection performance, augmentation of $T_{10}$ is required. Guide wall has been generally used to improve $T_{10}$ because $T_{10}$ changes according to flow field. In this study, porous media is proposed instead of guide wall, and disinfection performance between guide wall and porous media wall are compared. Flow field and $T_{10}$ in each clearwell are investigated as well. Improved Disinfection performance appear in case of porous media wall compare to guide wall, and best performance occur in porosity factor ${\beta}$ 1e+4.

• Research in Plant Disease
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• v.17 no.1
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• pp.99-101
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• 2011

The ascomycetous fungus Taphrina wiesneri, the pathogen of cherry witches' broom, is highly pathogenic to Prunus yedoensis, the most widely planted cherry trees in Korea as park and roadside trees. A collection of 13 strains of the pathogen in Korea and Japan was characterized by 18S rDNA gene sequence and restriction fragment length polymorphism (RFLP) analysis. In cluster analysis based on 18S rDNA gene sequence the strains were divided into 2 clusters. In RFLP analysis of the rDNA-IGS region using HhaI, the strains were separated into four patterns, B, C, D and G, of which pattern G was new.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.3
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• pp.331-337
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• 2013

Post-chlorination for disinfection in portable water process is final process. The design factors of post-chlorination are inflow pipe line from tank of filtrated water to cleanwell, injection point of chlorine, appropriate shape of baffle in cleanwell for disinfection efficient improvement. Until now, we did not have the design standard for post-chlorination. we evaluated most suitable design method of post-chlorination process in portable water process by using computational fluid dynamics in this research. We found the result that the pipe to connect the cleanwell should be one. If pipe line split into two or more, uniform distribution of the flow is difficult. Second, optimal injection point of chlorine is the middle of pipe line to connect the cleanwell. Therefore, it is not economical to install chlorine contact basin in cleanwell. Third, the shape of baffle should be designed in order to water flows in one direction. And we found that it is better to design the low number of flow turning.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.767-772
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• 2006

The SWTR(Surface Water Treatment Rule) requires achieving removal 99.9% Giardia and 99.99% Virus. To remove Giardia and Virus, disinfection process is essential process. CT is important index for Disinfection performance. CT value is expressed by CXT. C is represented by disinfection concentration and T is represented by $T_{10}$ which means 90% contact time in clearwell. To improve Disinfection performance, it is desirable to increase $T_{10}$. Primary factor affected $T_{10}$ is flow Pattern. Because guide wall change that flow pattern is uniform, we have installed guide wall to increase $T_{10}$. In this paper, we have performed numerical analysis for clearwell installed symmetric guide wall and center divided guide wall using CFD. We have analyzed flow pattern and $T_{10}$ in each clearwell. And. we compare symmetric guide wall with center divided guide wall in flow pattern and $T_{10}$.

• Korean Journal of Materials Research
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• v.33 no.10
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• pp.385-392
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• 2023

A solution combustion process for the synthesis of hollandite (BaAl₂Ti₆O₁₆) powders is described. SYNROC (synthetic rock) consists of four main titanate phases: perovskite, zirconolite, hollandite and rutile. Hollandite is one of the crystalline host matrices used for the disposal of high-level radioactive wastes because it immobilizes Sr and Lns elements by forming solid solutions. The solution combustion synthesis, which is a self-sustaining oxi-reduction reaction between a nitrate and organic fuel, generates an exothermic reaction and that heat converts the precursors into their corresponding oxide products in air. The process has high energy efficiency, fast heating rates, short reaction times, and high compositional homogeneity. To confirm the combustion synthesis reaction, FT-IR analysis was conducted using glycine with a carboxyl group and an amine as fuel to observe its bonding with metal element in the nitrate. TG-DTA, X-ray diffraction analysis, SEM and EDS were performed to confirm the formed phases and morphology. Powders with an uncontrolled shape were obtained through a general oxide-route process, confirming hollandite powders with micro-sized soft agglomerates consisting of nano-sized primary particles can be prepared using these methods.

• Korean Journal of Child Studies
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• v.37 no.2
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• pp.27-42
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• 2016

Objective: The purpose of this study was to examine the changes of childcare expenses and private education expenses caused by target expanding the childcare subsidy policy and its relationship to household income. Methods: The study analyzed data of the Korean Welfare Panel Study from 2009, before the universal childcare policy was enforced, to 2013, when the universal childcare policy was enforced. Results and Conclusion: The results of analysis were as follows. First, while childcare expenses, private education expenses, and their ratios to household income showed a tendency of gradual decline, the graphs of childcare and private education expenses were symmetric. Second, there were differences in childcare and private education expenses among income classes. Third, in 2009, before the universal childcare policy was enforced, household income affected childcare and private expenses. Lastly, in 2013, after the universal childcare policy was implemented, household income had a greater effect on private education expenses, while the effect of household income on childcare expenses became insignificant.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.1
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• pp.105-112
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• 2008

Disinfection is a basic and effective microorganism inactivation method and historically contributed a decrease in waterborne diseases. To guarantee the disinfection ability, improving T in CT value is important. Many indexes are used to estimate the hydraulic efficiency, however, these are black-box analysis. Therefore it is need to develope new estimation method. In this study, internal short-circuiting estimation method (ISEM) is developed using CFD and we inquire into the factor which causes increase of $T_{10}/T$ value as LW ratio increases. And the effect of shape on the relation of LW ratio and $T_{10}/T$ is analyzed. As LW ratio increases, internal short-circuiting index (ISI) of influent and effluent zone is rapidly reduced and recirculation and dead zone are reduced in channel zone. Therefore, as the $T_{10}/T$ value converges maximum value, ISI curve is changed from "V" shape to "U" shape and hydraulic efficiency is improved especially in downstream portion of clearwell. The less the shape ratio(width/length of clearwell) is the less the $T_{10}/T$ value is at a same LW ratio because the portion of turning zone increases as shape ration decreases, therefore more boundary separation is generated.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.6
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• pp.819-826
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• 2005

To guarantee the disinfection ability in clearwell, a value of CT is considered where C[mg/l] is disinfectant residual at the exit of clearwell and T[min] means $T_{10}$, the contact time when 10% of tracer is out of clearwell after introducing the tracer at the inlet. To meet a CT value required, increasing the C value is not recommended because high C value can increase potential of producing disinfection by product like THMs. Increasing the hydraulic efficiency surrogated by $T_{10}$ is thus an option widely recommended. Right now, it is widely adopted estimating $T_{10}$ considering LW ratio only due to the suggestions of previous researches. The authors think however there are other factors to consider including shape, flow rate, configuration of inlet and outlet, and the existence of intra basin. This study is initiated to closely look at the effects of two factor on hydraulic efficiency. The factors are shape and inlet flow velocity, i.e., inflow. For that, computational fluid dynamics (CFD) model is developed and pilot test is also carried out. The results show that at a L/W ratio, disinfection ability is overestimated with larger length in shape and higher inlet flow velocity. This suggests that in determining $T_{10}$, the shapes of clearwell and inlet flow velocity should also be considered as well as L/W ratio.

• Human Ecology Research
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• v.58 no.1
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• pp.1-12
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• 2020

This study examined if the effect of family functioning on preschoolers' school readiness can be mediated by mothers' affective parenting and preschoolers' self-regulation in the year before children enter elementary school. This study analyzed the 7^th year data of panel study of Korean children collected by the Korean Institute of Child Care and Education. Statistical analysis included 1,513 pairs of 6-year-old children and mothers. Descriptive statistics analysis, correlation analysis, structural equation modeling, and bootstrapping analysis were conducted using SPSS 22 and Amos 20. The primary findings were as follows. First, the sub-factors of preschoolers' school readiness composed of children's social and emotional development, approach to learning, cognitive development and general knowledge, and communication were positively correlated with family functioning, mothers' affective parenting, and preschoolers' self-regulation. Second, the result of structural equation modeling showed that the indirect paths from family functioning to preschoolers' school readiness through mothers' affective parenting and preschoolers' self-regulation were significant, while the direct path was insignificant. Third, bootstrapping analysis showed that mothers' affective parenting and preschoolers' self-regulation fully mediated the relationship between family functioning and preschoolers' self-regulation. The findings provide the grounds for families and parents with preschool aged children to implement effective support practices to maintain a functional family system that can promote preschoolers' school readiness.