• Journal of Powder Materials
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• v.21 no.2
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• pp.142-146
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• 2014

Fundamental experiences have been studied for development of pre-treatment process of Sn by-products such as solders. Dry and wet separation/recovery processes were considered by the differences of physical properties. The by-products, which are analyzed by solder metal and oxides. The metal and oxide were simply separated by dry ball-milling process for 12 hours, after that recovery metal powder might be reusable as lead or lead-free solders. In terms of wet separation process, samples were dissolved in $HNO_3+H_2O_2$ and the precipitation were analyzed by $SnO_2$. Overall efficiency of recovery might be increasing via developing simple pre-treatment process.

• The Journal of the Korean dental association
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• v.46 no.7
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• pp.440-445
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• 2008

Dentinogenesis imperfecta is one of the most common autosomal dominant traits experienced in humans. It generally affects both the deciduous and permanent dentitions. There are 3 forms of dentinogenesis imperfecta that have been classified into type I(osteogenesis imperfecta associated), type II(hereditary opalescent dentin), and type III(Brandywine isolate opalescent dentin).1,2 The prevalence for all types of dentinogenesis imperfecta is approximately 1 per 8000 subjects. Early diagnosis and treatment are therefore, fundamental, aiming at obtaining a favourable prognosis since late intervention makes treatment more complex. This clinical report describes a treatment solution to the problems encountered by a dentinogenesis imperfecta patient with minimally invasive techniques.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.12
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• pp.1143-1147
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• 2005

In this study, we report an improved efficiency of Organic light emitting diodes(OLEDs), using $UV/O_3$ treated anode and different cathode. We investigated the efficiency of OLEDs by $UV/O_3$ treatment of ITO surface. We Performed $UV/O_3$ treatment and found that $UV/O_3$ treatment enhanced the performance of OLEDs. The fundamental structure of the OLEDs was ITO $anode/{\alpha}-NPD/Alq_3/Al$ or Li:Al cathode. The Li:Al can improve the OLEDs efficiency dramatically in cathode because it has lower work function than Al. Current-voltage, Luminance-voltage characteristics and luminance efficiency were measured at room temperature.

• Transactions of Materials Processing
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• v.14 no.3 s.75
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• pp.215-223
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• 2005

A numerical analysis program is developed by FDM scheme for the prediction of microstructural transformation during heat treatment of steels. In this study, multi-phase model was used fur description of diffusional austenite transformations in low-alloy hypoeutectoid steels during cooling after austenitization. A fundamental property of the model consisting of coupled differential equations is that by taking into account the rate of austenite grain growth, it permits the prediction of the progress of ferrite, pearlite, and bainite transformations simultaneously during quenching and estimate the amount of martensite also by using K-M eq. In order to simulate the microstructural evolution during tempering process, another Avrami-type eq. was adopted and method for vickers hardness prediction was also proposed. To verify the developed program, the calculated results are compared with experimental ones of casting product. Based on these results, newly designed heat treatment process is proposed and it was proved to be effective for industry.

• Proceedings of the KIEE Conference
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• 2007.04b
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• pp.61-63
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• 2007

In these days there are many troubles - system data error, control malfunctions, cable overheating - in water treatment plant. Specially DAF(Dissolved Air Floation Process) plant has high frequency than previous water treatment process. DAF plant has diverse equipment, nonlinear loads for the precise control. But there is no sufficient overall study about harmonics condition of water treatment plant just taking a following partial action without a fundamental solution. On designing of power system, designer should have regard to harmonics condition, but there is no guide reflected harmonics condition on DAF plant This study says what is the result of guideless design about harmonics. With the result of diagnosis and analysis in DAF plant, economical efficiency and safety of plant will be upgraded in the next design.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2001.11a
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• pp.64-69
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• 2001

This study is the fundamental report to propose the capability of discarded Bentonite by heat-treatment as concrete mineral admixture. The experiment is performed by flow test of mortar and by compressive strength of 7, 14, 28, 91 days, As a result of experiment about mortar using discarded Bentonite by heat-treatment, in the case of $500^{\circ}C$, $600^{\circ}C$, $700^{\circ}C$, $800^{\circ}C$.60min, compressive strength is superior to the every situation than plain Mortar. Especially, in the case of $700^{\circ}C$.60min, as strength activity index is measured by 109%, it can be applied as concrete mineral admixture. But, flow of Mortar using discarded Bentonite by heat-treatment is decreased about 2.5cm in the case of 30min and about 1.7cm in the case of 60min.

• Textile Coloration and Finishing
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• v.6 no.1
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• pp.19-27
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• 1994

Mimosa and Quebracho are, in general, tanned with leather skin, finished silk fabrics according to temperature, treatment time, tannin concetration, pH, and studies that relation between tannin weighting and various factors. This makes fundamental study on characteristic of tannin treated fabrics. and the results are as fallows : 1. λ$_{max}$ was found at 278.5nm for Mimosa. 279.5nm for Quebracho. Also a stability was good in standing time and heating. 2. The higher tannin treatment temprature was, the better tannin weighting effect was. But they were slightly decreased at over 8$0^{\circ}C$, and K/S was slowly increased. 3. As tannin treatment time increased, tannin weighting effect increased but they were decreased at over 8$0^{\circ}C$, 90min. 4. As tannin concentration increased, tannin weighting was increased. 5. In tannin weighting effect according to various pH conditions, the it's best range of pH were 3.5~5.5 of Mimosa, 2.5~3.5 of Quebracho.o.

• Coupled systems mechanics
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• v.8 no.6
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• pp.489-500
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• 2019

With drinking water standards becoming more rigorous and increasing demands for additional water quantities, while water resources are becoming more polluted, mathematical models became an important tool to improve water treatment processes performance in the water supply system. Water treatment processes models reflect the knowledge of the processes and they are useful tools for water treatment process optimization, design, operator training for decision making and fundamental research. Unfortunately, in the current practice of drinking-water production and distribution, water treatment processes modeling is not successfully applied. This article presents a review of some existing water treatment processes simulators and the experience of their application and indicating the main weak points of each process. Also, new approaches in the modeling of water treatment are presented and recommendations are given for the work in the future.

• Structural Engineering and Mechanics
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• v.2 no.4
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• pp.327-343
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• 1994

This is the second part of the paper (Rojek and Kleiber 1993) devoted to nonlinear dynamic analysis of structures consisting of rigid and deformable parts. The first part contains a theoretical formulation of nonlinear equations of motion for the coupled system as well as a solution algorithm. The second part presents the computer implementation of the equations derived in the first part with a short review of the capabilities of the computer program used and the library of finite elements. Details of material nonlinearity treatment are also given. The paper is illustrated by discussing a practical problem of a safety cab analysis for an agricultural tractor.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.217-222
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• 1994

Generally speaking, grouting on the base stabilizes the ground as the aspects of mechanic and engineering properties, with drilling hole at any depth of the earth, and pressuring the cement milk or special chemical grouting material in it. The purpose of grouting on the base is waterproofness and solidification of the ground by earth concreting that the cement milk pass through paticles of soil or crack of rock. This report shows the fundamental properties of microcement compared with those of ordinary portland cement in a point of grouting. It also describes that experimental applications on the treatment of the weathered rock at the constructior of Taegu subway and Boryong earth filled dam site, south of chungchung province, resulted in success.