• 한국재료학회지
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• 제28권4호
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• pp.235-240
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• 2018

We propose a speedy two-step deposit process to form an Au electrode on hole transport layer(HTL) without any damage using a general thermal evaporator in a perovskite solar cell(PSC). An Au electrode with a thickness of 70 nm was prepared with one-step and two-step processes using a general thermal evaporator with a 30 cm source-substrate distance and $6.0{\times}10^{-6}$ torr vacuum. The one-step process deposits the Au film with the desirable thickness through a source power of 60 and 100 W at a time. The two-step process deposits a 7 nm-thick buffer layer with source power of 60, 70, and 80 W, and then deposits the remaining film thickness at higher source power of 80, 90, and 100 W. The photovoltaic properties and microstructure of these PSC devices with a glass/FTO/$TiO_2$/perovskite/HTL/Au electrode were measured by a solar simulator and field emission scanning electron microscope. The one-step process showed a low depo-temperature of $88.5^{\circ}C$ with a long deposition time of 90 minutes at 60 W. It showed a high depo-temperature of $135.4^{\circ}C$ with a short deposition time of 8 minutes at 100 W. All the samples showed an ECE lower than 2.8 % due to damage on the HTL. The two-step process offered an ECE higher than 6.25 % without HTL damage through a deposition temperature lower than $88^{\circ}C$ and a short deposition time within 20 minutes in general. Therefore, the proposed two-step process is favorable to produce an Au electrode layer for the PSC device with a general thermal evaporator.

• 대한치과재료학회지
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• 제45권4호
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• pp.257-274
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• 2018

본 논문에서는 순수 티타늄(cp-Ti) 임플란트를 SLA (Sandblasting with Large grit and Acid) 처리할 때 산-처리 용액의 유형, 산-처리 온도 및 산-처리 시간 등이 티타늄 표면에 주는 영향을 평가하고자 하였다. 원판형의 cp-Ti 시편을 준비하여 표면을 인산칼슘계 세라믹 분말로 RBM (Resorbable Blast Media) 처리하였다. 산-처리 용액으로 염산을 30 vol%로 고정하고 황산의 농도를 10, 20, 30, 35 vol%로 증가시키며 혼합한 용액에 증류수를 추가하여 4종의 산-처리 용액을 준비하였다. 실험군은 4종의 산-처리 용액, 3 종의 처리온도 및 3 종의 처리시간 등 36 가지로 분류하여 실험군당 4개의 시편을 산-처리하였다. 산-처리 전 후 시편 무게를 전자저울로 측정하여 무게 감소비율을 계산하였고, 공초점주사전자현미경으로 표면거칠기를 측정하였다. X-선 회절분석기(XRD)로 XRD 패턴을 측정하였고, 주사전자현미경으로 표면 형상을 관찰하였으며, 에너지 분산형 분석기(EDX)와 광전자분광법(XPS)로 표면성분을 분석하였다. 무게 감소비율과 표면거칠기 측정값은 Tukey-multiple comparison test (p = 0.05)로 통계 분석하여 다음의 결과를 얻었다. 산-처리에 따른 티타늄 시편의 무게 감소는 황산의 농도 및 산-처리 용액의 온도가 높을수록 유의하게 증가하였다. 산-처리한 티타늄의 표면 거칠기는 산-처리 조건(황산 농도, 온도, 시간)에 일정한 영향을 받지 않았다. XRD 분석에서 산-처리한 모든 시편에서 티타늄(${\alpha}-Ti$)과 수소화 티타늄($TiH_2$) 결정상이 관찰되었고, XPS 분석으로 티타늄 표면에 얇은 n산화 티타늄 층이 형성된 것을 알 수 있었다. $90^{\circ}C$ 산-용액에서 처리할 경우 티타늄 표면이 과도하게 용해될 수 있으므로 주의하여야 한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1028-1030
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• 1995

In the fields of the optics, precise machine, semiconducting processing, the micro-positioning actuators are required for the control of position in the submicron range. In this study, $Pb(Ni_{1/3}Nb_{2/3})O_3-Pb({Zn}_{1/3}Nb_{2/3})O_3-Pb({Zr}_{1/2}Ti_{1/2})O_3$ ceramics were fabricated by solid state reaction. The structural, dielectric and electric properties were investigated for sintering condition. The specimen sintered at $1,150(^\circ}C)$ for 1hr, had the highest density and dielectric contant. The resistivity, dielectric and density were increased with increasing PZN contents.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.319.2-319.2
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• 2016

ZrN 코팅은 TiN과 특성이 유사한 옅은 금색의 질화 박막이나 내식성이 우수하여 의료용, 자동차 부품, 항공부품, 장식용으로 적용되고 있다. 스테인레스계 의료용 기구나 생활기구의 항균성 기능이 부여된 표면처리는 아직 널리 보급되고 있지 않아 장식성과 내부식성이 뛰어난ZrN 박막에 구리를 함유시킴으로서 항균성의 변화를 관찰하고자 하였다. 진공 아크 이온플레이팅 방법으로서 ZrN을 성장시키면서 스퍼터링법에 의하여 Cu를 함유시키는 방법으로 실험을 실시하였다. 기재는 SUS 304를 사용하였고, 공정온도 $400^{\circ}C$에서 질소분압 1-5 Pa, 아크전류 90 A의 조건에서 Cu 스퍼터링 타겟의 전류를 1-7A 까지 변화하여 구리함유 ZrN 박막을 합성하였다. 구리 함류량에 따른 XRD를 통한 결정구조분석과 SEM/EDX를 통한 성분변화분석을 실시하였다. 구리함유 박막에 대해서 시간에 따른 대장균을 성장을 분석하여 기재인 SUS304, ZrN, 구리 함유 ZrN에 대한 대장균 항균성을 조사하였다.

• 산업기술연구
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• 제22권A호
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• pp.37-42
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• 2002

The shearing process for the sheet metal is normally used in the precision elements such as a frame of TFT-LCD or lead frame of IC chips. In these precision elements, the burr formation prevents the system assembly and needs the additional burr removing process. In this study, we have developed the novel ultrasonic deburring system to remove the small burr came from shearing of the sheet metal effectively. The deburring tool is driven by the stepping motor and alumina and SiC particles are used as abrasives. Ultrasonic power and the flowing resistance of the abrasives make ti possible to abrasive the burr.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.737-739
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• 1992

The microstructure and humidity sensitive characteristics of $V_2O_5$ doped $CaTiO_3$ were studied. Sensing elements were prepared in bulk form. This element exhibits a porous structure. The grain grows and electrical conductivity increases as doping amount of $V_2O_5$ increases. The change of impedance and capacitance under different r.h is remarkable, and the conduction carriers of this element were ions.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.685-691
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• 1993

This paper introduces a PC-based image data processing unit that is composed of preprocessor board and main processor board; The preprocessor contains Inmos A110 processor and efficient H/W architecture for fast mask/logic operations at the speed of video signal rate. It is controlled by the main processor which communicates with the host PC. The main processor board contains TI TMS320C31 digital signal processor, and can access the frame memory of the processor for extra S/W tasks. We test 3*3, 5*5 masks and logic operations on 386/486/DSP and compare the result with that of the proposed unit. The result shows ours are extremely faster than conventional CPU based approach, that is, over several hundred times faster than even DSP.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.683-686
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• 2001

The thermomechanical characteristics of NITINOL shape memory alloy were evaluated using DSC with small samples and DMA with three-point bending specimens. The shape memory alloy of 54.4Ni/45.5Ti wt.% was used so that the austenite finish temperature was in the range of $50~100^{\circ}C$. Two types of sample were tested in the experiments corresponding to as-received and annealed conditions. Simple beam bending theory was used to calculate the dynamic moduli of the shape memory alloy. According to the results, a large discrepancy in transformation temperatures was found between DSC and DMA techniques. Annealing treatment was found to suppress the R-phase transformation during cooling and the secondary plateau in the austenite transformation. Such a heat treatment was also significantly influenced to raise the transformation temperatures and the moduli of the shape memory alloy.

• 한국세라믹학회지
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• 제31권11호
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• pp.1355-1361
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• 1994

With the availability of ceramics (Al2O3, Al2O3-TiC), it is possible to machine very hard steel at different cutting conditions. When hardened steel STD 11 is turned using ceramic tools, chip formation is observed conical-herical and arc chips with a cyclic saw toothed type. The main cause of saw toothed chip formation is observed conical-herical and arc chips with a cyclic saw toothed type. The main cause of saw toothed chip formation is found to be periodic gross shear fracture extending from the free surface of the chip toward the tool tip. In regard to chip control, ceramic Al2O3 is superior to the other cutting tools. The roughness of machined surface was getting worse with increasing of cutting speed and feed.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
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• pp.383-389
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• 1999

The purpose of this study was to investigate the effects of alloying and rolling condition on the mechanical properties and to develop high strength line pipe steels with good toughness. Tests were carried out by the laboratory experiments followed by mill trials and mass production. It was found that a small addition of microalloying elements, such as Nb, V with Mo or Ti remarkably increased the strength and toughness of hot strips. The optimum condition of thermomechanical rolling on low carbon microalloyed steel improved the toughness through the formation of a fine and uniform microstructure. Based on this mill trials following the fundamental research, the production technology of line pipe steels, grade X70∼X100 with high toughness, has been established. These grade steels exhibit excellent low temperature toughness (vTs= under -80$^{\circ}C$) and sufficient strength in both the base metal and the ERW seam weld position, respectively.