• 한국결정성장학회지
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• 제30권4호
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• pp.123-130
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• 2020

AGM 연축전지(Absorbent Glass Mat Lead-Acid Battery)의 수명 특성을 결정짓는 양극 활물질(Active Material)의 주요 구성 결정인 4BS(Tetrabasic lead Sulfate)의 입자 크기를 제어하기 위해 4BS Nano Seed(NS)를 적용 중에 있다. 4BS NS 적용 시, 나노 입자 특성상 분산 안정성이 저하되어 제 기능을 다하지 못한다. 이를 개선하기 위해 기존 첨가제인 광명단(Red Lead)에 나노 입자의 4BS seed가 포함된 Incorporated Nano Seed(INS)를 함량별로 첨가하여 양극판 분석과 제품 성능을 평가하였다. INS 함량이 증가할수록 4BS 입자 크기는 작아지면서 균일해지는 특성을 확인할 수 있었으며, 반응 비표면적 증가에 따른 고율 방전 특성도 향상되는 것을 알 수 있었다. 극판 제조 공정에서의 개별 극판에 대한 입도 분포의 편차를 확인하기 위해, AGM 연축전지 200 대 대한 내부 저항 및 전압 검사를 진행하였으며 제품 제조 공정 품질 편차가 감소하는 것을 확인하였다.

• 한국생산제조학회지
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• 제22권4호
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• pp.747-754
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• 2013

This study introduces a recently designed desktop-sized NC turning system and its components. This machine is designed for the ultra-precise turning of parts with a diameter of 0.5-20 mm with minimum space usage for the machine. This study aims to achieve submicron-level accuracy of movements and good rigidity of the machine for precision machining using the desktop-sized machine. The components such as the main machine structure, air bearing servo spindle, and XZ stage with needle roller guides are designed, and the designed machine is built with a PC-based CNC controller. Its static and dynamic stiffness performances and positioning resolutions are tested. Through machining tests with single-crystal diamond tools, a form error less than $0.8{\mu}m$ and surface roughness (Ra) of $0.03{\mu}m$ for workpieces are obtained.

• Composites Research
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• 제33권2호
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• pp.55-60
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• 2020

구조용 일액형 에폭시 접착제에 나노 및 마이크로 크기의 Fe₃O₄ 분말을 첨가하여 유도가열용 접착제를 제조하였고, 제조된 접착제를 이용하여 GFRP 피착재의 두께 및 Fe₃O₄ 분말의 첨가량 변화에 따른 가열 성능을 평가하였다. 실험 결과, 접착제의 승온 거동이 유도 가열로 가열한 경우 오븐경화에 비해 GFRP 피착재의 두께에 영향을 작게 받는 것이 관찰되었으며 접착제 내의 Fe₃O₄ 분말의 함량이 증가할수록 가열 속도와 전단 강도가 증가하는 경향을 나타냈다.

• Structural Engineering and Mechanics
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• 제86권4호
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• pp.487-501
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• 2023

Nanoparticles have lower size and larger specific surface area, good stability and less toxic and side effects. In recent years, with the development of nanotechnology, its application range has become wider and wider, especially in the field of biomedicine, which has received more and more attention. Bone defect repair materials with high strength, high elasticity and high tissue affinity can be prepared by nanotechnology. The purpose of this paper was to study how to analyze and study the composite materials for sports bone injury based on multifunctional nanomaterials, and described the electrospinning method. In this paper, nano-sized zirconia (ZrO₂) filled micro-sized hydroxyapatite (HAP) composites were prepared according to the mechanical properties of bone substitute materials in the process of human rehabilitation. Through material tensile and compression experiments, the performance parameters of ZrO₂/HAP composites with different mass fraction ratios were analyzed, the influence of filling ZrO₂ particles on the mechanical properties of HAP matrix materials was clarified, and the effect of ZrO₂ mass fraction on the mechanical properties of matrix materials was analyzed. From the analysis of the compressive elastic modulus, when the mass fraction of ZrO₂ was 15%, the compressive elastic modulus of the material was 1222 MPa, and when 45% was 1672 MPa. From the analysis of compression ratio stiffness, when the mass fraction of ZrO₂ was 15%, the compression ratio stiffness was 658.07 MPa·cm³/g, and when it was 45%, the compression ratio stiffness is 943.51MPa·cm³/g. It can be seen that by increasing the mass fraction of ZrO₂, the stiffness of the composite material can be effectively increased, and the ability of the material to resist deformation would be increased. Typically, the more stressed the bone substitute material, the greater the stiffness of the compression ratio. Different mass fractions of ZrO₂/HAP filling materials can be selected to meet the mechanical performance requirements of sports bone injury, and it can also provide a reference for the selection of bone substitute materials for different patients.

• 대한토목학회논문집
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• 제29권1B호
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• pp.91-96
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• 2009

LDH(Layered double hydroxide) 물질을 제조하고 이를 이용하여 비소를 흡착시키는 실험을 수행하였다. TEM을 이용하여 제조한 LDH 물질의 형상을 살펴본 결과 열처리를 거친 시료는 나노크기의 결정화된 구조를 가지고 있고 열처리를 거치지 않은 시료는 아직 결정화가 완전히 이루어지지 않았으며 크기도 마이크로 범위에서 나타났다. X선 회절분석 결과를 보면 이 같은 결과가 뚜렷이 나타났으며, 열처리를 거친 경우는 뚜렷한 결정화를 보이고 있었다. $N_2$ 흡착 및 탈착 결과를 통해 LDH가 mesoporous한 공극 형태를 가지고 있다는 것을 알 수 있었다. 비표면적은 열처리를 거친 시료가 열처리를 거치지 않은 시료보다 2배 이상 크게 나타났다. 흡착 등온 실험 결과에서도 두 시료는 비슷한 흡착량을 보이며 기존 철산화 물에 못지않은 흡착능을 나타내고 있다. 금번에 합성한 Mg Fe-LDH 물질을 이용하여 토양 및 지하수의 비소 제거 공정에 적용할 수 있음을 확인하였다.

• Transactions on Electrical and Electronic Materials
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• 제12권4호
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• pp.160-163
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• 2011

Polymer nanocomposite has been attracting more attention as a new insulation material because homogeneous dispersion of nano-sized inorganic fillers can improve various properties significantly. In this paper, various kinds of epoxy-based nanocomposites were made, and the AC breakdown strengths of Nano filler and micro-$SiO_2$ filler mixtures of epoxy-based composites were analyzed using sphere-to-sphere electrodes. Moreover, nano- and microfiller combinations were investigated as an approach to practical application of nanocomposite insulation materials. Its composition ratio was 100 (resin):82 (hardener):1.5 (accelerator). AC breakdown tests were performed at room temperature ($25^{\circ}C$), $80^{\circ}C$, and $100^{\circ}C$ in the vicinity of $T_g$ ($90^{\circ}C$). Thermal conductivity was measured using TC-30.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.99-99
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• 2010

Polymer nanocomposite has been attracting much attention as a new insulation material, since homogeneous dispersion of nm-sized inorganic fillers can improve various properties significantly. In this paper, various kinds of epoxy based nanocomposites were made and AC breakdown strength of Nano-TiO2 and micro-silica filler mixture of epoxy based composites were studied by sphere to sphere electrode. Moreover, nano- and micro-filler combinations were adopted as an approach toward practical application of nanocomposite insulation materials. Nano-TiO2 particle size is about 10nm and composites ratio was resin (100) : hardener (82) : accelerator (1.5). AC breakdown test was performed at room temperature (25 [$^{\circ}C$], 80 [$^{\circ}C$] and 100 [$^{\circ}C$] in the vicinity of Tg (90[$^{\circ}C$]). And thermal conductivity were measured by ASTM-D5470.

• 한국재료학회지
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• 제20권10호
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• pp.513-517
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• 2010

There have been many efforts to modify and improve the properties of functional thin films by hybridization with nano-sized materials. For the fabrication of electronic circuits, micro-patterning is a commonly used process. For photochemical metal-organic deposition, photoresist and dry etching are not necessary for microscale patterning. We obtained direct-patternable $SnO_2$ thin films using a photosensitive solution containing Ag nanoparticles and/or multi-wall carbon nanotubes (MWNTs). The optical transmittance of direct-patternable $SnO_2$ thin films decreased with introduction of nanomaterials due to optical absorption and optical scattering by Ag nanoparticles and MWNTs, respectively. The crystallinity of the $SnO_2$ thin films was not much affected by an incorporation of Ag nanoparticles and MWNTs. In the case of mixed incorporation with Ag nanoparticles and MWNTs, the sheet resistance of $SnO_2$ thin films decreased relative to incorporation of either single component. Valence band spectral analyses of the nano-hybridized $SnO_2$ thin films showed a relation between band structural change and electrical resistance. Direct-patterning of $SnO_2$ hybrid films with a line-width of 30 ${\mu}m$ was successfully performed without photoresist or dry etching. These results suggest that a micro-patterned system can be simply fabricated, and the electrical properties of $SnO_2$ films can be improved by incorporating Ag nanoparticles and MWNTs.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.158-158
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• 2011

A wide range of techniques for the direct-printing of functional materials have been developed for the fabrication of micro- and nanoscale structures and devices. Here we report a new direct patterning method, liquid bridge-mediated nanotransfer molding (LB-nTM), for the formation of two- or three-dimensional structures with feature sized as small as tens of nanometers over large areas up to 4". LB-nTM is based on the direct transfer of various materials from a mold to a substrate via a liquid bridge between them. The LB-nTM method was applied to the preparation of organic nanowire FETs on flexible substrates.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.935-936
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• 2009

In this paper, we describe the basic operating mechanism of our novel reflective display, Fast Moving Ball Actuator (FMBA) mode[1], using micro-sized metal coated polymer ball in fluid medium. Metal surface of the ball can be charged up by contact electrode and their locations can be controlled by applied field to obtain optically on and off state. In the medium with high viscosity, the response speed of the moving ball might be reached into their terminal velocity and changed in proportion to the frequency of applied voltage on the electrodes.