• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.133-133
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• 2012

일반적으로 TiO2는 광촉매 작용으로 표면 살균성을 가지며, 친수특성으로 인한 자가세정 능력도 가지고 있다. 또한 지구상에 많이 존재하는 광물로 원료의 가격이 저렴하다는 장점이 있어 산업 전반에 사용되고 있다. 하지만 외부의 환경적 오염으로 인한 광촉매 반응 면적의 감소에 따라 반응효율이 저하되는 단점이 있으며, SiO2는 투명한 유리와 같이 비정질상태가 안정하고 높은 굴절률을 가지며 내구성이 외부환경에 강해 무반사 코팅이나 금속박막의 보호층으로 주로 사용된다. WO3는 높은 굴절률과 가시광선 영역에서의 우수한 투과율을 가지고 있으나 conduction band에서 생성된 광캐리어들이 빠르게 재결합 하여 광분해 효율이 좋지 않기 때문에 흔히 쓰이지 않고 있다. 이러한 박막들의 단점을 보완하기 위해 물리적 구조를 변화시켜 반응 면적을 극대화하기 위해 버퍼층이나 다층박막을 사용하는 등 다양한 연구가 진행되고 있다. 본 실험에서는 Slide glass에 Plasma etching 하였을때 친수성이 나타나는 특성을 이용하여 대면적 코팅과 표면 경도를 우수하게 만들 수 있는 RF Magnetron sputtering법으로 Slide glass에 Ar Gas 분위기에서 각 파워별 Plasma etching한 후 TiO2, SiO2, WO3 박막을 증착하여 광학적, 구조적 특성을 분석하였다. 광투과율 측정장치(UV-VIS Spectrophotometer)를 사용하여 투과율을 측정한 결과 모든 박막이 가시광 영역에서 80% 이상의 높은 투과율을 나타내었으며, 접촉각 측정결과 100w로 etching한 glass에 TiO2를 증착한 박막에서 가장 낮은 $3^{\circ}$ 이하의 접촉각을 나타내었다. SEM (Scanning Electron Microscope) 분석을 통해 표면구조를 관찰한 결과 100w로 etching한 후 TiO2를 증착한 박막이 가장 조밀한 구조를 보였으며, AFM (Atomic Force MicroScope) 분석 결과 100w로 etching한 후 TiO2를 증착한 박막의 표면이 가장 거칠어지는 것을 볼 수 있었는데, 이는 물과 닿는 박막의 유효 표면적의 증가로 인하여 광촉매 효과가 증가하였기 때문에 친수성이 향상된 것으로 사료된다. 이러한 박막은 건물 유리벽과 자동차의 내 외장재 전자기기용 광학 필름에 자가세정, 내반사 코팅소재, 디스플레이 표시장치로 활용할 수 있을 것으로 예상된다. 본 연구는 중소기업청에서 지원하는 2011년도 산학연 공동기술개발 지원사업의 연구수행으로 인한 결과물임을 밝힙니다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.433-433
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• 2012

As the requirement in patterning geometry continuously shrinks down, the termination of etch process at the exact time became crucial for the success in nano patterning technology. By virtue of real-time optical emission spectroscopy (OES), etch end point detection (EPD) technique continuously develops; however, it also faced with difficulty in low open ratio etching, typically in self aligned contact (SAC) and one cylinder contact (OCS), because of very small amount of optical emission from by-product gas species in the bulk plasma glow discharge. In developing etching process, one may observe that coupon test is being performed. It consumes costs and time for preparing the patterned sample wafers every test in priority, so the coupon wafer test instead of the whole patterned wafer is beneficial for testing and developing etch process condition. We also can observe that etch open area is varied with the number of coupons on a dummy wafer. However, this can be a misleading in OES study. If the coupon wafer test are monitored using OES, we can conjecture the endpoint by experienced method, but considering by data, the materials for residual area by being etched open area are needed to consider. In this research, we compare and analysis the OES data for coupon wafer test results for monitoring about the conditions that the areas except the patterns on the coupon wafers for real-time process monitoring. In this research, we compared two cases, first one is etching the coupon wafers attached on the carrier wafer that is covered by the photoresist, and other case is etching the coupon wafers on the chuck. For comparing the emission intensity, we chose the four chemical species (SiF2, N2, CO, CN), and for comparing the etched profile, measured by scanning electron microscope (SEM). In addition, we adopted the Dynamic Time Warping (DTW) algorithm for analyzing the chose OES data patterns, and analysis the covariance and coefficient for statistical method. After the result, coupon wafers are over-etched for without carrier wafer groups, while with carrier wafer groups are under-etched. And the CN emission intensity has significant difference compare with OES raw data. Based on these results, it necessary to reasonable analysis of the OES data to adopt the pre-data processing and algorithms, and the result will influence the reliability for relation of coupon wafer test and whole wafer test.

• Journal of Conservation Science
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• v.33 no.5
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• pp.363-370
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• 2017

The aim of this study was to obtain information about two early-20th Century clothes, for which the "National Memorial Museum of Forced Mobilization under Japanese Occupation" has sought to receive preservation treatment. Optical microscopes and a scanning electron microscope were used to investigate the weaving of the clothes, and Fourier transform infrared spectroscopy(FT-IR) was used to investigate the fibers. Cloth A is believed to be a Japanese half sleeved inner wear(Hanjuban) used by women. Cloth B is believed to be working clothing that was checked by an Osaka plant. This was verified by a book written by the Japanese army. Both of the clothes were made mostly from cotton, although the inner wear also used viscose rayon on the neck collar. The button on the working wear was made of urea formaldehyde resin, an early precursor to plastic.

• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.311-316
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• 2010

This study aimed to prepare antimony-doped tin oxide (ATO) dispersion with high stability. The methods to achieve this goal were sought by investigating the changes of ATO particle size, size distribution, dispersion property as wet ball milling treatment time increased. And the changes of wet ball milled ATO dispersion property were also investigated, as pH increased. The changes of ATO particle size and size distribution, according to wet ball milling treatment time were evaluated with laser diffraction particle size analyzer and scanning electron microscope (SEM). The changes of ATO dispersion property, as wet ball milling treatment time and pH increased, were evaluated with zeta potential analysis and Turbiscan. By 60 min wet ball milling treatment time, ATO particle size decreased and size distribution became narrower, as the treatment time increased. After 60 min milling, the ATO particle size decreased to less than 30% of the initial size and the size distribution was narrowed to $0.1{\sim}5{\mu}m$ from $1{\sim}35{\mu}m$. However, more than 60 min milling, ATO particles aggregated and the particle size increased. ATO dispersion stability also increased as the treatment time and pH increased because the reduced particle size increased particle surface energy and repulsion between particles and the increased pH enhanced particle surface ionization. Hence, after proper length of wet ball milling treatment, highly stable ATO dispersion can be prepared, as increasing pH of the dispersion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5074-5081
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• 2015

A method for improving the warpage of the plastic part is a method of removing residual stress of the plastic product. that a non-uniform cooling are appeared in the injection molding process make uniform cooling. this study was developed the Rapid heating and cooling device used peltier module for uniform cooling. Make the Rapid heating and cooling device(RCHD), for Traditional water cooling device(TWCD) method and the Rapid heating and cooling method warpage were compared and were analyzed and the materials used amorphous ABS polymer. various warpage were compared for the process parameters such as packing pressure, packing time, resin temperature, mold temperature, In the amorphous ABS polymer, TWCD method has higher warpage than RCHD method and show the result to be a bit more uniform cooling. The distribution state of the ABS polymer was confirmed Through the Scanning electron microscope. In the TWCD method the distribution state of the polymer be densely distributed, and RCHS method be distributed wider than TWCD method. this is that injection molded parts be seen that cooling was made uniformly, As the temperature of the mold is gradually progress, Particles of the polymer is increased this is that internal stress was reduced.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.123-123
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• 2012

최근 연구되고 있는 TSV(Through Silicon Via) 기술은 Si 웨이퍼 상에 직접 전기적 연결 통로인 관통홀을 형성하는 방법으로 칩간 연결거리를 최소화 할 수 있으며, 부피의 감소, 연결부 단축에 따른 빠른 신호 전달을 가능하게 한다. 이러한 TSV 기술은 최근의 초경량화와 고집적화로 대표되는 전자제품의 요구를 만족시킬 수 있는 차세대 실장법으로 기대를 모으고 있다. 한편, 납땜 재료의 주 원료인 주석은 주로 반도체 소자의 제조, 반도체 칩과 기판의 접합 및 플립 칩 (Flip Chip) 제조시의 범프 형성 등 반도체용 배선재료에 널리 사용되고 있다. 최근에는 납의 유해성 때문에 대부분의 전자제품은 무연솔더를 이용하여 제조되고 있지만, 주석을 이용한 반도체 소자가 고밀도화, 고 용량화 및 미세피치(Fine Pitch)화 되고 있기 때문에, 반도체 칩의 근방에 배치된 주석으로부터 많은 알파 방사선이 방출되어 메모리 셀의 정보를 유실시키는 소프트 에러 (Soft Error)가 발생되는 위험이 많아지고 있다. 이로 인해, 반도체 소자 및 납땜 재료의 주 원료인 주석의 고순도화가 요구되고 있으며, 특히 알파 방사선의 방출이 낮은 로우알파솔더 (Low Alpha Solder)가 요구되고 있다. 이에 따라 본 연구는 4인치 실리콘 웨이퍼상에 직경 $60{\mu}m$, 깊이 $120{\mu}m$의 비아홀을 형성하고, 비아 홀 내에 기능 박막증착 및 전해도금을 이용하여 전도성 물질인 Cu를 충전한 후 직경 $80{\mu}m$의 로우알파 Sn-1.0Ag-0.5Cu 솔더를 접합 한 후, 접합부 신뢰성 평가를 수행을 위해 고속 전단시험을 실시하였다. 비아 홀 내 미세구조와 범프의 형상 및 전단시험 후 파괴모드의 분석은 FE-SEM (Field Emission Scanning Electron Microscope)을 이용하여 관찰하였다. 연구 결과 비아의 입구 막힘이나 보이드(Void)와 같은 결함 없이 Cu를 충전하였으며, 고속전단의 경우는 전단 속도가 증가할수록 취성파괴가 증가하는 경향을 보였다. 본 연구를 통하여 전해도금을 이용한 비아 홀 내 Cu의 고속 충전 및 로우알파 솔더 볼의 범프 형성이 가능하였으며, 이로 인한 전자제품의 소프트에러의 감소가 기대된다.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.5
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• pp.675-686
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• 2007

Statement of problem: Titanium nitride(TiN) coatings are the most general and popular coating method and used to improve the properties of metallic surface for industrial purposes. When TiN coating applied to the abutment screw, frictional resistance would be reduced, as a results, the greater preload and prevention of the screw loosening could be expected. Purpose: The purpose of this study was to investigate mechanical properties of TiN coated film of various coating thickness on the titanium alloy surface and to evaluate proper coating thickness. Material and method: 95 Titanium alloy (Ti-6Al-4V) discs of 15 mm in diameter and 3 mm in thickness were prepared for TiN coating and divided into 7 groups in this study. Acceding to coating deposition time (CDT) with TiN by using Arc ion plating, were divided into 7 groups : Group A (CDT 30min), Group B (CDT 60min), Group C (CDT 90min), Group D (CDT 120min), Group E (CDT 150min), Group F(CDT 180min) and Group G (no CDT) as a control group. TiN coating surface was observed with Atomic Force Microscope(AFM), field emission scanning electron microscopy(FE-SEM) and examined with scratch tester, wear tester. Result: 1. Coating thickness fir each coated group was increased in proportion to coating deposition time. 2. Surface of all coated groups except Group A was homogeneous and smooth. However, surface of none coated Group G had scratch. 3. Adhesion strength for each coated group was increased in proportion to coating deposition time. 4. Wear resistance for each coated group was increased in proportion to coating deposition time. 5. Surface roughness in Group A, B, C was increased in proportion to coating deposition time. But, surface roughness in Group D, E, F was showed decreased tendency in proportion to coating deposition time. Conclusion: According to coating deposition time, mechanical properties of TiN coated film were changed. It was considered that 120 minutes coating deposition time ($1.32{\mu}m$ in coating thickness) is necessary.

• Journal of the Korean Ceramic Society
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• v.40 no.10
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• pp.991-997
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• 2003

The effect of A1$_4$C$_3$ additive on the thermoelectric properties of SiC ceramics were studied. Porous SiC ceramics with 47∼59% relative density were fabricated by sintering the pressed $\alpha$-SiC powder compacts with A1$_4$C$_3$at 2100∼220$0^{\circ}C$ for 3 h in Ar atmosphere. Crystalline phases of the sintered bodies were identified by powder X-Ray Diffraction (XRD) and their microstructures were observed with a Scanning Electron Microscope (SEM). In the case of A1$_4$C$_3$ addition, the phase transformation of 6H-SiC to 4H-SiC could be observed during sintering. The Seebeck coefficient and electrical conductivity were measured at 550∼95$0^{\circ}C$ in Ar atmosphere. In the case of undoped specimens, the Seebeck coefficients were positive (p-type semiconducting) possibly due to a dominant effect of the acceptor impurities (Al, Fe) contained in the starting powder and electrical conductivity increased as increasing sintering temperature. Electrical conductivity of A1$_4$C$_3$doped specimen is larger than that of undoped specimen under the same condition, which might be due to the reverse phase transformation and increasing of carrier density. And the Seebeck coefficient of A1$_4$C$_3$ doped specimen is also larger than that of undoped specimen. The density of specimen, the amount of addition and sintering atmosphere had significant effects on the thermoelectric property.

• Journal of the Korean Magnetics Society
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• v.19 no.6
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• pp.209-215
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• 2009

M-type barium ferrite (BaFe12O19) powders were synthesized through the co-precipitation method. Starting material composition $Fe^{3+}:\;Ba^{2+}$ mole ratio was fixed as 8 and the relative amount of $Fe^{3+}$ and $Ba^{2+}$ was controlled. Structure and magnetic properties and powder morphology were investigated using XRD, SEM, VSM. Powder showing high coercivity and small magnetization was obtained at pH8 and $Fe_{3+}:\;Ba_{2+}$ of 12 : 1.5. Small magnetization value was originated from the existence of ${\alpha}-Fe_2O_3$. Single-phase Mtype barium ferrite were obtained regardless of the heat treatment condition and the amount of $Fe_{3+}\;and\;Ba_{2+}$ at pH$\approx$10. The largest value of magnetization (55.7 emu/g) under investigation were obtained when $Fe_{3+}:\;Ba_{2+}$ of 13.6 : 1.7 and furnace cooled powder in $O_2$. Particle size of powder was in the range of 50~200 nm.

• Corrosion Science and Technology
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• v.8 no.4
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• pp.162-169
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• 2009

Pure titanium and its alloys are drastically used in implant materials due to their excellent mechanical properties, high corrosion resistance and good biocompatibility. However, the widely used Ti-6Al-4V is found to release toxic ions (Al and V) into the body, leading to undesirable long-term effects. Ti-6Al-4V has much higher elastic modulus than cortical bone. Therefore, titanium alloys with low elastic modulus have been developed as biomaterials to minimize stress shielding. For this reason, Ti-30Ta-xZr alloy systems have been studied in this study. The Ti-30Ta containing Zr(5, 10 and 15 wt%) were 10 times melted to improve chemical homogeneity by using a vacuum furnace and then homogenized for 24 hrs at $1000^{\circ}C$. The specimens were cut and polished for corrosion test and Ti coating and then coated with TiN, respectively, by using DC magnetron sputtering method. The analyses of coated surface were carried out by field emission scanning electron microscope(FE-SEM). The electrochemical characteristics were examined using potentiodynamic (- 1500 mV~+ 2000 mV) and AC impedance spectroscopy(100 kHz~10 mHz) in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. The equiaxed structure was changed to needle-like structure with increasing Zr content. The surface defects and structures were covered with TiN/Ti coated layer. From the polarization behavior in 0.9% NaCl solution, The corrosion current density of Ti-30Ta-xZr alloys decreased as Zr content increased, whereas, the corrosion potential of Ti-30Ta-xZr alloys increased as Zr content increased. The corrosion resistance of TiN/Ti-coated Ti-30Ta-xZr alloys were higher than that of the TiN-coated Ti-30Ta-xZr alloys. From the AC impedance in 0.9% NaCl solution, polarization resistance($R_p$) value of TiN/Ti coated Ti-30Ta-xZr alloys showed higher than that of TiN-coated Ti-30Ta-xZr alloys.