• 접착 및 계면
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• 제13권2호
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• pp.73-84
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• 2012

공기-유리 사이의 계면에서 광학적 정보가 전달되는 메카니즘을 알아보기 위하여, 유리컵을 잡은 손가락 지문(골과 능선)의 선명도에 미치는 불완전 전반사(Frustrated Total Internal Reflection: FTIR)와 수분 효과를 이론과 실험을 통해 조사하였다. 물이 든 컵을 잡은 손가락의 경우, 지문이 아주 선명하였는데 이는 컵 바닥으로부터 출발한 빛이 유리벽에서 전반사(Total Internal Reflection: TIR)된 빛과 지문 능선에서 반사된 빛의 세기가 서로 달라서 나타남을 기하광학, Fresnel 이론, TIR 및 FTIR 현상을 이용하여 밝혀내었다. 또한 공기-유리 경계면에서 지문의 선명도에 미치는 FTIR과 수분 효과를 실험적으로 관측한 결과, 지문이 선명하게 보이는 현상은 FTIR 현상보다는 수분의 효과가 훨씬 더 지배적이라는 사실을 처음으로 규명하였다.

• Restorative Dentistry and Endodontics
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• 제19권1호
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• pp.45-63
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• 1994

128 freshly extracted human molars were used to study the interaction between dentinal smear layer removal with various agents, and the shear bond strength of a light cured glass ionomer cement to dentin. It was proposed that the removal of smear layers using acidic cleaners followed by incorporation of Fe mordant with dentin could enhanced the infiltration of monomer component in light curing glass ionomer cement and resulted in a high bond strength. For the first treatment process for removal of smear layers on the surfaces of dentin, 50 % citric acid, 10% maleic acid and 10 % phosphoric acid were used, and for the second treatment process, 15% ferric chloride, 6.8% ferric oxalate or 30% potassium oxalate were used. Distilled water was used as a control. After double sequential treatment on dentin, a light curing glass ionomer cement was bonded to dentin. After being immersed in water at 31'C for 24 hours, shear bond strengths were measured Instron testing machine(Model No.4202, USA). Surface changes were also observed using SEM (Hitachi, S-2300, Japan) after treatment process with each agents. The following conclusions were drawn : 1. Dentin surface cleaned with maleic acid and treated with ferric oxalate showed the highest bond strength with light curing glass ionomer cement. 2. Bond strengths of glass ionomer cement to dentin treated with maleic acid or citric acid were the highest, and that treated with phosphoric acid showed the lowest. 3. The effect of ferric oxalate on shear bond strength to dentin was always higher than that of ferric chloride. 4. The smear layers were clearly removed and the orifices of dentinal tubules were opened widely by the citric acid, maleic acid and phosphoric acid. 5. The orifices of dentinal tubules opened after using the first solution were closed with the treatment of ferric chloride. 6. The precipitate like crystals were formed on dentin surfaces and tubules, but a significant decrease in bond strength of glass ionomer cement to dentin surface treated with potassium oxalate.

• Restorative Dentistry and Endodontics
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• 제19권1호
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• pp.217-230
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• 1994

The purpose of this study was to assess the 24-hour shear bond strength of amalgam to glass ionomer cement, using five different intermediaries. The intermediaries used in this study were Scotchbond 2 (light curing dentin adhesive), Panavia (resin cement), liquid' of glass ionomer cement (chemical curing & light curing), and uncured mixture of light curing glass ionomer cement. This study was operated with 48 specimens devided into 6 groups. The experimental groups are as follows: Group 1 : Bonded Amalgam to chemical curing glass ionomer cement with liquid of chemical curing glass ionomer. Group 2 : Bonded Amalgam to light curing glass ionomer cement with liquid of chemical curing glass ionomer. Group 3: Bonded Amalgam to light curing glass ionomer cement with resin cement. Group 4: Bonded Amalgam to light curing glass ionomer cement with light curing dentin adhesive. Group 5: Bonded Amdlgam to light curing glass ionomer cement with liquid of light curing glass ionomer. Group 6: Bonded Amalgam to light curing glass ionomer cement with uncured mixture of light curing glass ionomer cement. 30 minutes after amalgam condensation, all specimens were stored for 24 hours in water at $37^{\circ}C$ and tested with Instron (1122). The following results obtained: 1. The shear bond strength of group 6 was higher than those of the other groups (46.7 kgf/$cm^2$, p<0.05). 2. The shear bond strength of resin cement intermediary group was lower than that of the group using uncured mixture of light curing glass ionomer cement. 3. The results of group 1 and group 2 were different, even though the inter-me diaries used were same. 4. Intermediary of Group 5 did not show complete set in Scanning Electromicroscopic examination. 5. Light-curing dentin adhesive did not show any bonding ability to amalgam.

• 한국결정성장학회지
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• 제23권3호
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• pp.146-151
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• 2013

본 연구에서는 석탄 바닥재와 준설토(7 : 3, 무게비율)로 제조된 인공골재의 물성에 미치는 폐촉매 유리질 슬래그(이하 폐유리로 칭함) 첨가 영향을 평가하였다. 특히 인공골재의 비중 및 흡수율 결과를 미세구조와 연계하여 그 발포특성을 고찰하였다. $1050{\sim}1150^{\circ}C$ 범위 내에서 인공골재 비중은 소성온도와 함께 약간 증가되었으나 그 이상의 소성온도에서는 감소하여 발포경향을 나타내었다. 폐유리 첨가량이 증가할수록 인공골재의 발포특성은 억제되었으며, 비중은 증가하는 경향을 보였다. 한편 인공골재 흡수율은 소성온도의 증가와 함께 감소하였다. $1200^{\circ}C$ 이상의 소성온도에서 표면에 균열이 발생함과 동시에 다량의 액상이 형성되었으나, 이러한 현상들은 폐유리를 첨가함으로서 제어할 수 있었다. 본 연구에서 제조된 인공골재의 비중은 1.1~1.6, 흡수율은 8~22 % 범위값을 나타내어 인공경량골재의 KS 기준을 만족하였다.

• 한국안광학회지
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• 제5권2호
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• pp.187-192
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• 2000

본 연구에서는 물 유리의 경제성을 바탕으로 광학적 및 기계적인 특성을 조사하여 투명하고 높은 경도를 가진 표면 보호막의 기능을 검토하기 위하여 $SiO_2-Na_2O-R_mO_n$계 박막을 제조하였다. 물 유리에 CaO와 $Al_2O_3$를 소량의 1 N HCl 1N $NH_4OH$와 함께 각각 첨가하여 코팅용 졸을 준비하였다. Stainless steel. Si wafer. soda-lime-silica glass등 다양한 기판 위에 spin-coating 한 후 질소 분위기 하에서 500, 750 및 $900^{\circ}C$로 최종 열처리를 행했다. 제조된 막은 Knoop 경도계로 micro-hardness를 측정하였다. 막의 표면 질소 함유량을 알아보기 위하여 EDX 분석을 행하였다. 그리고 Field Emission Scanning Electron Microscope(FE-SEM)을 이용하여 막의 표면구조를 관찰하였으며, UV-VIS 스펙트라 측정을 통하여 막의 두께와 반사 특성을 조사하였다.

• Composites Research
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• 제23권1호
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• pp.44-50
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• 2010

본 연구에서는 염수 침수 실험과 염수 분무 실험이라는 두 가지의 실험을 위그선의 구조재료로 사용될 3가지 다른 복합재료 시스템에 대해서 해수와의 접촉에 의한 물성저하를재현하기 위해 수행하였다. 140일간 염수환경하에서 노화시킨 후 탄소섬유 복합재료와유리섬유 복합재료의 인장, 압축, 전단 강성과 강도 및 층간 전단 강도를 측정하였다. 기본 물성파의 비교를 통해서 염수환경이 복합재료의 기계적 물성에 미치는 영향이 평가되었다. 실험을 통해 염수 분무환경과 침수 환경의 차이는 거의 영향을 미치지 않음을 확인하였다. 탄소섬유 복합재료의 경우 인장 물성에 적은 손실이 발생한 반면 유리섬유 복합재료에서는 인장물성의 저하률이 탄소섬유 복합재료에 비해서 큼을 확인하였다. 그리고 모재 지배적 물성들의 큰 물성저하가 관찰되었다. 이를 통해, 염수는 복합재료의 섬유와 모재 사이의 계면을 퇴화시키고, 또한 모재 자체 물성과 유리섬유의 물성을 저하시킬 수 있음을 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 추계학술대회 논문집
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• pp.43-45
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• 1988

This paper deals with the effect amino silane coupling agent for the composite insulating material (GFRP). Three kinds of coupling agent treatments are studied, that is treatment on glass fiber, epoxy resin and both glass fiber and epoxy resin. The result shows that the optimum electrical and mechanical properties is obtained for the sample treated on the glass fiber with 0.3% amino silane water solution.

• 디지털산업정보학회논문지
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• 제10권2호
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• pp.37-45
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• 2014

This paper is a study of the water sensor using a coaxial cavity resonator. This water sensor uses the resonant frequency variation of the coaxial cavity resonator when there is a water drop of the used coaxial cavity resonator. And we made resonant frequencies by controlling the input voltage of the oscillator which will be mainly resonated in the coaxial cavity resonator. First, we made the coaxial cavity resonator by simulating the resonator structure with the proposed size and we expect the resonant frequency from the simulation and then we decide the VCO from the result. Second, we made the water drop detecting sensor circuit and measured the water sensor. We decided the size of the resonator as inner conductor 5mm, outer conductor 14mm, the height of resonator 9.5mm, and the height of the glass 6mm from the simulated result. The simulated resonant frequencies are 3.09GHz and we made the VCO frequency ranges from 2.56GHz to 3.2GHz. The measured resonant frequency is 2.97GHz and the return loss is under -8. 4 dB at the center frequency. When the water is dropped on the glass of the resonator, the voltage has changed from 690mV to 145mV. It shows the proposed water sensor can detect the water by the resonant frequency variation of the resonator.

• 한국물환경학회지
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• 제25권3호
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• pp.370-374
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• 2009

Adsorption characteristics of glass fibers, obtained from the spent lithium primary batteries recycling process, were investigated for the removal of Acid Red 27 dye from aqueous solution. The batch data clearly showed that increasing the initial sorptive concentration apparently enhanced the amount adsorbed and the uptake process followed the pseudo-second order rate model. The equilibrium adsorption data at different initial sorptive concentrations were fitted well to Freundlich and Langmuir adsorption isotherms. Moreover, the increase in temperature, favored the uptake of dye on this solid, indicated the process was endothermic in nature. Further, using the temperature dependence sorption data obtained at different temperatures was used to estimate various thermodynamic parameters.

• 설비공학논문집
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• 제15권9호
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• pp.779-785
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• 2003

The present work proposed a newly developed fluidized bed-type psychrometer that could be applicable to the high temperature and contaminant gases. The psychrometer is a device that test gas passes through the water in a glass bottle as a bubbly flow to obtain the adiabatic saturation temperature. A fluidized bed-type psychrometer was made and its characteristics were compared with the Assmann Psychrometer. The characteristic time was in the order of a hundred seconds, and decreased for the decrease of the mass of water and the increase of the air flow rate. The air flow rate and the insulation of the glass bottle were definitely important in the accurate measurement of the wet bulb temperature. The error in wet bulb temperature became less than 5 percent of the difference of dry and wet bulb temperatures if the air velocity in the glass bottle was greater than 1.5m/s.