• Journal of Environmental Health Sciences
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• v.27 no.4
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• pp.9-14
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• 2001

This study was performed to develop the modified FGD(Flue Gas Desulfurization) process which can eliminate the possibility of generating secondary pollutants. Limestone was regenerated by adding ammonium hydroxide and carbon dioxide, and reusing it as a absorbent in FGD gypsum Process. A series of the new or modified FGD process which include desulfurization and regeneration limestone from CaSO$_3$. 1/2H20 and CaSO4 . 2H2O, were carried out under various experimental conditions. The results showed that the optimum injection ratio for regeneration of limestone was 0.3 ml/min of CO2 flow rate, 2 ml of NH4OH per 0.01 M of regent grade CaSO4 . 2H20O and the optimum regeneration temperature was 50. The increaser was the number of times of limestone regeneration, the faster was the breakthrough point of desulfurization at the desulfurination process which the regenerated limestone was used. Then the efficiency of desulrurization was decreased. This study can be confirmed the possibility for reuse of regenerated limestone due to the similarity of desulfurization characteries both reagent grade calcium carbonate and regenerated calcium carbonate. Finally, it appeared that the new technology using regenerated 1imestone can be applied to the FGD process.

• Korean Journal of Childcare and Education
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• v.13 no.2
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• pp.21-37
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• 2017

Objective: The current study aimed at examining the mediation effects of children's self-esteem and self-control in learning between perceived academic achievement at $4^{th}$ grade and $6^{th}$ grade. This article proposes that perceived academic achievement boosts self-esteem and self-control in learning and both in turn, influence subsequent perceived academic achievement. We especially attempted to empirically prove that a serial multiple mediation of self-esteem and self-control in learning between the perceived academic achievement at two time points exists. Methods: We analyzed the longitudinal data of 1,881 children from the $4^{th}$ to the $6^{th}$ wave data of the '2010 Korea Children and Youth Panel Survey (KCYPS)' by means of a Hayes's PROCESS(2012) program. Results: The results revealed that perceived academic achievement at $4^{th}$ grade influenced children's self-esteem and self-control in learning at $5^{th}$ grade. Children' self-esteem and self-control in learning subsequently predicted perceived academic achievement at $6^{th}$ grade. Children's self-esteem significantly predicted self-control in learning supporting the hypothesis of serial multiple mediation. Conclusion/Implications: In conclusion, children's self-esteem and self-control in learning behaviors both mediated the association between perceived academic achievement at $4^{th}$ grade and at $6^{th}$ grade. The findings imply the importance of consideration of both psychosocial and behavioral aspects in understanding the academic performance during childhood.

• Journal of Korean Neurosurgical Society
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• v.46 no.1
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• pp.16-22
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• 2009

Objective : This study was designed to investigate automated pressure-controlled discography (APCD) findings, to calculate the elastance of intervertebral discs, and to assess the relationship between the calculated elastance and disc degeneration. Methods : APCD was performed in 19 patients. There were a total of 49 intervertebral discs treated. Following intradiscal puncture, a dye was constantly injected and the intradiscal pressure was continuously measured. The elastance of the intervertebral disc was defined as unit change in intradiscal pressure per fractional change in injected dye volume. Disc degeneration was graded using a modified Dallas discogram scale. Results : The mean elastance was 43.0${\pm}$9.6 psi/mL in Grade 0, 39.5${\pm}$8.3 psi/mL in Grade 1, 30.5${\pm}$22.3 psi/mL in Grade 2, 30.5${\pm}$22.3 psi/mL in Grade 3, 13.2${\pm}$8.3 psi/mL in Grade 4 and 6.9${\pm}$3.8 psi/mL in Grade 5. The elastance showed significant negative correlation with the degree of degeneration ($R^2$=0.529, P=0.000). Conclusion: APCD liberates the examiner from the data acquisition process during discography. This will likely improve the quality of data and the reliability of discography. Elastance could be used as an indicator of disc degeneration.

• Journal of the Korean Solar Energy Society
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• v.36 no.5
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• pp.9-18
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• 2016

G-SEED(Green Standard for Energy and Environmental Design) is the certification system to evaluate environmental friendliness of buildings for the purpose of reducing environmental burden generated from the entire process of buildings, which is classified into 4 grades according to the evaluated score. Green building certification rule regulate to get over green 2nd grade for the public office buildings of $3000m^2$ or more. However, detailed measures on the applied level of each issue to obtain targeted certification grade have not been prepared yet. For each issue, the score distribution and the ratio of score in proportion to credit were analyzed by certification grade for office buildings which get the G-SEED certification. And applied level of issues were presented for each certification grade.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.1
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• pp.116-127
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• 2004

The objectives of this study are to build up the concept of Environment-Oriented Land Suitability Assessment(EOLSA) and to develop the EOLSA mapping system by applying the EOLSA criteria to the case study area. In order to draw out the EOLSA critera, this study adopted the Delphi method including the experts' awareness survey to urban planners as well as environmental researchers in May and June 2001. As a result, the concept of EPLSA was defined as a process of land use planning to scientifically assess the physical and environmental value of land and to classify conservation aptitude into several grades for the sustainable management of environmental resources. With an outcome of applying the EOLSA criteria with five degrees to the Seoul Metropolitan Area (SMA), Grade I, indicating the highest conservation value, accounted for 57.76% of the SMA. Then, Grade II reached up to 15.06%, Grade III 3.12%, Grade IV 15.92%, and Grade V, the lowest conservation value, 7.99% respectively. And also, the case analysis showed that the share of Grade I area was the highest in Gapyong county and Yangpyong county, Pochon county, Yeonchon county, Yongin city in the order and the lowest in Kwangmyong city, Osan city, Kunpo city, Kuri city, and Buchon city.

• Korean Journal of Metals and Materials
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• v.47 no.5
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• pp.304-310
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• 2009

Recently, manganese nodule has been focused on alternative resources because of its high grade of noble metallic elements such as Co, Ni, and Cu etc. From the viewpoint of an optimization the operating variables for energy efficiency of smelting reduction process, thermodynamic model for smelting reduction process of Manganese nodule was developed by using energy and material balance concept. This model provided that specific consumption of pure oxygen and coke was strongly depended on post combustion ratio (PCR) and heat transfer efficiency (HTE). The dressing and dehydrating process of low grade manganese can be proposed an essential process to minimize the specific energy consumption with decreasing slag volume. The effect of electricity coal base smelting reduction process was also discussed from the energy optimizing point of view.

• Journal of the Korean School Mathematics Society
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• v.18 no.3
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• pp.281-309
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• 2015

The purpose of this study is provides an implication of further teaching learning process by analyze the common and difference and characteristic of mathematical self-efficiency between three peer tutoring groups discourse in the mathematical teaching leaning process that use peer tutoring. To achieve this goal, three groups formed that consist of one peer tutor who received a first grade of mathematic achievement and one peer student. Peer student of each group is divided into high grade, middle grade, low grade of mathematic achievement. Then analyze the discourse in the exponential function problem solving process. Based on the results of study, this paper provides a concrete example of merit of peer tutoring on the peer tutor. Result of study also provides a practical help to make a peer tutoring group by considering a difference of grades between peer tutor and peer student. Because there is a possibility of mutual discourse on the tutoring group that consist of similar grades.

• Journal of the Korean institute of surface engineering
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• v.49 no.3
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• pp.280-285
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• 2016

In this study, we investigated the influences of potassium fluoride(KF) addition on the surface characteristics of plasma electrolytic oxidation(PEO) coating produced on Al alloy. The PEO of marine grade Al alloy(5083 grade) was conducted in KOH 1g/L solution adding different concentrations of KF(0, 1 and 2 g/L) under a galvanostatic regime. With KF addition, unusual behavior was observed on the voltage-time characteristic curves, which can be characterized by the following process: (i) initial rapid increase in voltage (ii) a short plateau after 1st breakdown (iii) gradual increase in voltage (iv) intermittent fluctuation of voltage after 2nd breakdown. The SEM observation revealed irregular surface morphology with KF addition, as compared with one formed without KF addition, which had a reticulate structure. The XRD analysis detected the formation of aluminium hydroxide fluoride hydrate($H_{4.76}Al_2F_{3.24}O_{3.76}$) on surface grown by PEO process with KF. Particularly, at very early stage of the process (~ 120 s), thin film was formed having nanoporous structure, and F element was confirmed on surface by EDS analysis. The thickness and surface roughness of the coating increased with increasing KF concentration. As a result, KF addition was found to be less beneficial influences on PEO of marine grade Al alloy, and therefore needs further research to improve its capability.

• 한국도로학회:학술대회논문집
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• 2006.10a
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• pp.105-114
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• 2006

There are several methods determining an appropriate performance grade of virgin binder, which is re(erred as design binder, in RAP contained bituminous mixture design process. However, difficulties have been experienced in utilizing the methods in the field application in Korea, because SHRP binder test, the key tests to determine a design binder, requires well-trained personnel, high price equipment, and time consuming process. Thus, the study investigated the relationship among the binder aging level, RAP contents, and rheologica1 properties of binder. The study results provide mix designer with a simple method in selecting an appropriate grade of virgin binder.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.1
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• pp.17-23
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• 2017

This study is about the development and revision of a blower design for a ventilation system. In this study, to describe the flow in the 4000CMM grade blower, 3-dimensional steady-state turbulence was assumed to govern the flow equation. The flow field with velocity distribution according to the elbow duct of the ventilation system is also compared. Finally, vibration was observed in the blower at the installation to ventilation system. The cause was due to a problem in the manufacturing process of the airfoil type impeller.