• 한국재료학회지
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• 제13권5호
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• pp.285-291
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• 2003

The nanosized silver and gold particles are prepared by ERC method in which metal vapors with high temperature is rapidly quenched by coolants such as liquid nitrogen or liquid argon. In order to monitor the crystal structural changes on the internal and the surface of the nanosized noble metal particles, lattice parameter, internal strain and Debye-Waller factor are investigated, and the calculation of X-ray diffraction scattering intensity is performed. The lattice parameters of silver and gold particles agree with those of bulk materials, and crystal internal strain of the metal particles is not changed by rapid cooling. The Debye-Waller factor of gold particles is increased with decreasing particle size because of the surface softening phenomenon of nanosized particles, but the crystal structural change on the surface of the particles is not detected from the comparison the calculated X-ray diffraction profile with the experimental profile on gold particles with the particle size of 4 nm.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.545-545
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• 2007

Recently, innovative process has been investigated in order to replace the conventional high-cost micro patterning processes on the electronic products. To produce desirable profit margins from this low cost products, printed circuit board(PCB), will require dramatic changes in the current manufacturing philosophies and processes. Innovative process using metal nano particles replaces the current industry standard of subtractive etched of copper as a highly efficient way to produce robust circuitry on low cost substrates. An advantage of using metal nano particles process in patterned conductive line manufacturing is that the process is additive. Material is only deposited in desired locations, thereby reducing the amount of chemical and material waste. Simply, it just draws on the substrate as glass epoxy or polyimide with metal nano particles. Particles, when their size becomes nano-meter scale, show some specific characteristics such as enhanced reactivity of surface atoms, decrease in melting point, high electric conductivity compared with the bulk. Melting temperature of metal gets low, the metal nano particles could be formated onto polymer substrates and sintered under $300^{\circ}C$, which would be applied in PCB. It can be getting the metal line of excellent electric conductivity.

• 한국표면공학회지
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• 제22권2호
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• pp.78-87
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• 1989

Mechanism of formation of electroless composite coatings is similar to that of electrodeposited composite coating, but the amount of particles entraped in electroless coating is higher that the one of electrodeposited coatings. The methol of entrapment by the metal for SiC and Al2O3 particles is different from that for WC particles. In the former case the particles are gracually engulfed by the depositing metal, wheran with WC a metal envelope is rapidly fomed around each particles. This difference can be attributed to the difference in electrical resistivity of the particles. Inclusion density of SiC and Al2O3 particles during copeposition depend on the particle size, agitation condition, vabration conditions and electrolyte temperatures.

• 한국환경과학회지
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• 제15권12호
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• pp.1171-1175
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• 2006

Deposited road particles (DRPs) were analysed for heavy metal concentrations at four different roads in a city, Korea. The samples were collected using a roadway surface vacuum cleaning vehicle which was commonly used in collecting roadway surface particles. Six particle size ranges were analyzed separately for twelve heavy metal elements (Cd, Cr, Pb, Ni, Al, As, Co, Cu, Fe, Mn, Zn and Hg). At all sampling sites, the high concentration of the heavy metals occurred in the <74um particle size range, which conventional roadway cleaning vehicles do not remove efficiently. The Pb concentration significantly increased with decreasing particle size of DRPs, and other toxic heavy metals (Cd, Cr and Ni) also showed similar results. The heavy metal concentrations in the smaller size fraction of DRPs is important because they are contaminants that are preferentially transported by road runoff during rainfall.

• 한국분말재료학회지
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• 제7권1호
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• pp.19-26
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• 2000

Al-Cr-Zr metal powders were prepared by cryo-milling(-75$^{\circ}C$),ambi-milling(25$^{\circ}C$) and warm-milling(200$^{\circ}C$) to investige the effect of milling temperature. The morphogical changes and microstructural evolution of Al-6wt.%Cr-3wt.%Zr metal powder ball milling were investigated by SEM, OM and XRD. The cryo-milling at -75$^{\circ}C$ caused the more refinement of powder particle size than ambi-milling and warm-milling. The partic morpholgy of Al-Cr-Zr metal powders changed changes into spheroidal particles at 25$^{\circ}C$and spherical particles at 200$^{\circ}C$The spherical particles were formed by agglomertion and contiuous wrapping of the spheroidal particles. The calculated Al crystallite size in Al-Cr-Zr metal powders by the Scherer equation were refined rapidly for short milling time -75$^{\circ}C$compared with milling at 25$^{\circ}C$ and 200$^{\circ}C$.

• 공업화학
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• 제10권1호
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• pp.173-176
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• 1999

초임계수를 이용한 금속산화물의 미세입자 제조에 대하여 연구하였다. 금속염 수용액으로는 cobalt nitrate solution과 manganese nitrate solution을 sample solution으로 선택하여 코발트산화물과 망간산화물 입자를 제조하였다. 얻어진 결과로부터 초임계수를 이용한 금속산화물 미세입자의 제조가 가능함을 확인할 수 있었으며, 초임계수 하에서는 매우 빠른 dehydration반응이 일어남을 관찰할 수 있었다. 짧은 반응시간(30~100 초)에도 불구하고 미세입자 ($0.5{\sim}2{\mu}m$)가 생성되었으며, 초임계수 공정에서는 mixer의 온도가 입자의 크기 및 분포에 큰 영향을 미침을 알 수 있었다. 반응온도 조절을 통하여 입자의 크기를 제어할 수 있음을 확인할 수 있었다.

• 대한화학회지
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• 제43권1호
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• pp.1-7
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• 1999

이 논문에서는 광화학적 방법을 이용하여 금속 콜로이드 입자를 반도체 나노입자를 함유한 수용액내에서 제조하여 그 광학적 특성을 관찰하였다. 형성된 금속입자는 사용된 반도체 입자에 따라 다른 경향을 나타낸다. Au 금속 입자를 CdS 입자를 함유한 수용액내에서 제조한 경우 일반적인 금속 입자의 Plasmon Resonance의 특성을 보이는 반면 Ag금속 입자를 AgBr 입자를 함유한 용액내에서 제조한 경우 Red-Shift 현상을 보였고, 그 정도는 UV 조사량에 따라 달라졌다. 이러한 금속 Plasmon Resonance의 Red-Shift 현상을 Effective Medium 이론을 이용하여 이론적으로 설명하였다.

• Journal of Magnetics
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• 제21권4호
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• pp.635-643
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• 2016

Improvements were made in the study for the design of the conventional Eddy Current Separator (ECS) used for separating small sized non-ferrous particles in the waste. These improvements include decreasing the air gap between the material and magnetic drum, making the drum position adjustable and placing the splitter closer to the drum. Thus, small particles were separated with high efficiency. The magnetic drum was removed from inside the ECS conveyor belt system as design change and was placed as a separate unit. Hence, the force generated on the test material increased by about 5.5 times while the air gap between the non-ferrous materials and drum decreased from 3 mm to 1 mm. The non-metal material in the waste is separated before the drum in the novel design. Whereas non-ferrous metal particles are separated by falling into the splitter as a result of the force generated as soon as the particles fall on the drum. Every material that passes through the drum can be recycled as a result of moving the splitter closer to the contact point of the drum. In addition, the drum can also be used for the efficient separation of large particles since its position can be adjusted according to the size of the waste material. The performance of the novel design ECS was verified via analytical approaches, finite element analysis (FEA) and experimental studies.

• 센서학회지
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• 제17권2호
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• pp.95-99
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• 2008

Various etching methods of optical fiber and formation of metal nano particles on the optical fiber have been proposed for fabrication of fiber optic localized surface plasmon resonance (FO LSPR) biosensors. Different types of etched optical fiber are possible by removing the cladding of optical fiber using HF (hydrofluoric acid) solution and BHF (buffered hydrofluoric acid) solution, which results in improved surface roughness when BHF solution is used. Localized surface plasmon can be formed and measured by formation of silver and gold nano particles on the etched optical fiber. The characteristics of the etched optical fiber and metal nano particles on the etched surface of the optical fiber play a key role in dictating the sensitivity of the LSPR sensors, so that the proposed results can be expected to be applied for related research on fiber optic based biosensors.

• Environmental Engineering Research
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• 제10권2호
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• pp.45-53
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• 2005

Metal oxide particles with mole ratio of aluminum: titanium of 1:1 were synthesized by a sol-gel method. Langmuir (a) and Freundlich (b) adsorption isotherms of dissolved lead [Pb(Ⅱ)] ion on the metal oxide particles containing aluminum and titanium were determined as follows, respectively,(a) , (b) at pH 6where, correlation coefficients (R2) of Langmuir and Freundlich adsorption isotherms were 0.95 and 0.96, respectively.The overall adsorption rate of Pb(Ⅱ) on the metal oxide particles containing aluminum and titanium was determined by a differential bed reactor. The overall adsorption rate at pH 6 was as a following equation.at pH 6