• Computers and Concrete
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• 제13권4호
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• pp.531-545
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• 2014

The purpose of this paper is to develop a prediction model for the compressive strength of waste LCD glass applied in concrete by analyzing a series of laboratory test results, which were obtained in our previous study. The hyperbolic function was used to perform the nonlinear-multivariate regression analysis of the compressive strength prediction model with the following parameters: water-binder ratio w/b, curing age t, and waste glass content G. According to the relative regression analysis, the compressive strength prediction model is developed. The calculated results are in accord with the laboratory measured data, which are the concrete compressive strengths of different mix proportions. In addition, a coefficient of determination $R^2$ value between 0.93 and 0.96 and a mean absolute percentage error MAPE between 5.4% and 8.4% were obtained by regression analysis using the predicted compressive analysis value, and the test results are also excellent. Therefore, the predicted results for compressive strength are highly accurate for waste LCD glass applied in concrete. Additionally, this predicted model exhibits a good predictive capacity when employed to calculate the compressive strength of washed glass sand concrete.

• 한국초등과학교육학회지:초등과학교육
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• 제33권2호
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• pp.401-414
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• 2014

The purpose of this study is to investigate the elementary preservice teachers' conceptions about 'plastics' focusing on non-polar property from a National University of Education. For the study, the views about plastics, relative shapes of a water droplet on plastic or glass material, and relative shapes of water surface in the plastic or glass measuring cylinder were surveyed from the preservice teachers. And the responses were analyzed based on the patterns. The results from the study are as follows: First, most preservice teachers were well aware of the plastic products which are used in daily life. Second, the responses concerning the reason why plastics can be used commonly were divided into 2 categories with 14 sub-level groups. However relatively few preservice teachers mentioned regarding 'chemical stability' and 'conductivity', which are associated with the plastics' non-polar property. Third, it was found that 50 participants (30.1%) had 'Scientific conception (Sc)', 38 (22.9%) had 'Partial-scientific conception (Ps)', 66 (39.8%) had 'Misconception (Mc)', and 12 (7.2%) had 'No conception (Nc)' on the subject of the relative shapes of a water droplet. Fourth, the distribution patterns and the ratio of the preservice teachers' conception on the survey question 3 concerning the relative shapes of water surface were quite similar to those of the survey question 2. So it was concluded that overall understanding level of the preservice teachers was pretty low on the subjects of the relative polarities of the plastic, glass, and water as well as their interactions. Fifth, the distribution percentile of 'Sc'/'Ps'/'Mc'/'Nc' was not related with the gender but highly correlated with preservice teachers' academic field and their science subjects taken in high school. Based on the results from the study, some educational guidelines were suggested.

• 대한토목학회논문집
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• 제4권2호
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• pp.89-99
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• 1984

본(本) 연구(硏究)는 1.5 shot system의 대형약액주입장치(大形藥液注入裝置)에 의하여 물유리계 약액(藥液)을 주입(注入)시켜 고결토(固結土)에 대한 공학적(工學的) 특성(特性)을 구명(究明)하고 물유리계의 부족(不足)한 강도증대(强度增大)를 목적(目的)으로 보통포틀란드 시멘트를 병용(倂用)하여 그 주입효과(注入効果)를 판정(判定)한 것이다. 약액주입효과(藥液注入効果)는 지하수(地下水)의 유속(流速), 온도(溫度), 시료토(試料土)의 입도분포(粒度分布), 밀도(密度), 주입재(注入材)의 농도(濃度), 점도(粘度), Gel time, 주입량(注入量), 주입압력(注入壓力) 및 주입방식(注入方式) 등(等)에 좌우됨을 알고 이들 요소간(要素間)의 상관관계(相關關係)를 비교분석(比較分析)하였다. 현장주입시험(現場注入試驗)을 통(通)하여 유수중(流水中)에서의 희석(稀釋), 유실(流失)을 막아 주입효과(注入効果)의 증대(增大), 지반국부전단파괴(地盤局部剪斷破壞) 또는 지반융기현상(地盤隆起現象)에 대하여 검토(檢討)하였다.

• 대한기계학회논문집
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• 제17권6호
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• pp.1351-1360
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• 1993

본 연구에서는 수적법(hand lay up : HLU)을 이용하여 단 섬유포(chopped strand mat : CSM)형태의 유리섬유를 불포화 폴리에스테르 수지에 강화시킨 복합 적층 판을 대상으로 해수중에서 굽힘·피로시험을 실시하여 피로균열 성장거동을 관찰하고 파면관찰을 통하여 GERP의 피로특성을 검토하였다.

• 한국세라믹학회지
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• 제42권6호
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• pp.371-376
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• 2005

Phosphate glasses were prepared by melting quenching process, and glass formation and dissolution properties were studied. The glass forming region in the $K_2O-CaO-P_2O_5$ system is quietly agreed with the report by Mazurin OV et al. with $M_2O-M'O-P_2O_5$ system (M : monovalent cation, M'divalent cation). Conditionally these glasses have solubility from absorbing the moisture or water and then release elements with trace elements, and the thermal and chemical properties were controllable by the $CaO,\;K_2O,\;P_2O_5$ contents. In the abnormal glass properties, this paper showed the possibility the present glasses can be a good candidate for one component of the slow released agriculture fertilizer.

• 한국세라믹학회지
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• 제34권9호
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• pp.941-948
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• 1997

CuCl nanocrystallites dispersed nonlinear optical silica and borosilicate glasses were fabricated by sol-gel process. CuCl powder was dissolved in TEOS(Si(OC2H5)4) and TMB((CH3O)3B), precursors of silica and borosilicate glasses, with ethanol, water and HCl, and precipitated through the heat treatment in the matrix glass. The optical properties of CuCl doped glasses were measured using the spectrophotometer at room temperature and low temperature(77K); Z1, 2 and Z3 exciton peaks from the absorption spectra, were observed at about 370 nm and 380 nm, respectively. The average radius of nanocrystallites, calculated from the blue shift of Z3 excitons, was measured according to annealing temperature and time. The precipitation temperature of CuCl nanocrystallites was decreased when boron was added to silica glass. Increase of annealing temperature and time made average radius of nanocrystallites saturated about 2 nm.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.75-80
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• 2005

The present work was undertaken to numerically analyze the defrosting phenomena of windshield glass. In order to analysis the phase change from frost to water on windshield glass by discharging hot air from a defroster nozzle, the flow and the temperature field of the cabin interior, the heat transfer through the windshield glass, and the phase change of frost should be solve simultaneously. In the present work, the flow field was obtained by solving 3-D incompressible Navier-Stokes equations, and the temperature field was computed from the incompressible energy equation. The phase change process was solved by the enthalpy method. For the code validation, the temperature and the phase change of the driven cavity were calculated. The calculation showed a good agreement with other numerical results. Then, the present code was applied to the defrosting problem of a real automobile, and a good agreement with the experimental data was also obtained.

• Geomechanics and Engineering
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• 제12권1호
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• pp.71-83
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• 2017

Collapsible soil presents a porous unsaturated structure, its sudden settlement after humidification, without supplementary charge, can be of a big nuisance for the foundations and therefore for the constructions built on it. To improve its structure and limit its instability, samples of laboratory reconstituted soil, with different percentages of water contents and compacted at different compaction energies, were treated with glass-fiber. The study of the mechanical behavior was performed by oedometer tests. The microstructure was explored by the Scanning Electron Microscope (SEM). The results obtained show clearly the efficiency of the treatment with glass fiber on reducing the collapsibility of such soil.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.347-350
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• 2001

A typical Mold method is to form a gate electrode, a gate oxide, and emitter tip after fabrication of mold shape using wet-etching of Si substrate. In this study, however, new Mold method using a side wall space structure is used in order to make sharper emitter tip with a gate electrode. Using LPCVD(low pressure chemical vapor deposition), a gate oxide and electrode layer are formed on a Si substrate, and then BPSG(Boro phospher silicate glass) thin film is deposited. After, the BPSG thin film is flowed into a mold as high temperature in order to form a sharp mold structure. Next TiN thin film is deposited as a emitter tip substance. The unfinished device with a glass substrate is bonded by anodic bonding techniques to transfer the emitters to a glass substrate, and Si substrate is etched using KOH-deionized water solution. Finally, we made sharp field emitter array with gate electrode on the glass substrate.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.353-355
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• 1989

Composite insulating materials have the defect of interface. To minimize the defect of interface of GFRP (glass cloth reinforced plastics), coupling agent is treated. In this paper, the method of coupling agent treatment has been studied. The result shows that the optimum electric and mechanical properties is obtained for the sample treated on the glass fiber with 0.3% amino silane water solution.