• 분석과학
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• 제23권3호
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• pp.233-239
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• 2010

폴리스테린을 주형으로 사용하여 순수한 매크로포러스 실리카 지지체를 졸겔법에 의하여 제조하였으며, 은 입자가 매크로 기공 안에 균일하게 분산되어 있는 매크로포러스 은/실리카 복합소재를 성공적으로 제조하였다. 순수한 실리카 다공체는 폴리스테린 크기에 따라 100 nm와 200 nm의 균일한 기공을 가지고 있었으며 이는 폴리스테린의 크기에 따라 기공크기를 제어할 수 있었다. 매크로포러스 은/실리카 기공의 크기 제어와 $AgNO_3$의 농도에 따른 미세구조를 관찰한 결과 TEOS의 3 wt% $AgNO_3$를 사용한 것이 가장 이상적인 균일한 기공의 분포를 나타내었다. 매크로포러스 은/실리카 복합체는 100-200nm 균일한 기공을 가지고 있었으며, 지지체 내의 은 입자는 대략 15~20 nm 크기를 보여주었다.

• Journal of Welding and Joining
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• 제29권5호
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• pp.90-94
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• 2011

Ag metallic particles from nano-scale to submicron-scale are combined with organic solvent to provide fine circuits and interconnection. Ink-jet printing with Ag nano particle inks demonstrated the potentials of the new printed electronics technology. The bonding at the interface between the Ag wiring layer and the various substrates is very important. In this study, the details of interfaces in Ag wiring are investigated primarily by microstructure observation. By adjusting the materials and sintering conditions, nicely formed interfaces between Ag wiring and Cu, Au or organic substrates are achieved. In contrast, transmission electron microscope (TEM) image clearly shows interface debonding between Ag wiring and Sn substrate. Sn oxides are formed on the surface of the Sn plating. The formation of these is a root cause of the interface debonding.

• Elastomers and Composites
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• 제57권1호
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• pp.1-8
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• 2022

In this study, the photo-deposition method was used to introduce Ag onto the surface of TiO₂ to synthesize an Ag-TiO₂ composite. The effects of the varying amounts of AgNO₃ precursor and annealing time periods on the Ag content in the composites, as well as their antibacterial characteristics under visible light conditions were studied. SEM analysis revealed the spherical morphology of the Ag-TiO₂ composite. Compared with TiO₂, the Ag particles were too small to be observed. An XPS analysis of the Ag-TiO₂ surface confirmed the Ag content and showed the peak intensities for elements such as Ag, Ti, O, C, and Si. The highest Ag content was observed when 33.3 wt.% of AgNO₃ and an annealing time of 6 h were employed; this was the optimum annealing time for Ti-Ag-O bonding, in that the lowest number of O bonds and the highest number of Ag bonds were confirmed by XPS analysis. Superior antibacterial properties against Bacillus and Escherichia coli, in addition to the widest inhibition zones were exhibited by the Ag-TiO₂ composite with an increased Ag content in a disk diffusion test, the bacterial reduction rate against Staphylococcus aureus and Escherichia coli being 99.9%.

• 한국산학기술학회논문지
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• 제9권2호
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• pp.298-302
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• 2008

초경합금입자와 탄소강사이의 브레이징 접합부 특성을 평가하였다 선택된 두 종류의 삽입금속은 기계적 합금 공정으로 만들어졌다. 한 가지는 Cu, Zn, Ag (MIM-1) 그리고 다른 한 가지는 Cu, Zn, Ag과 Cd(MIM-2)로 구성하였다. 삽입금속들의 화학조성은 AWS BAg-20계와 BAg-2a계의 성분과 유사하였다. 그리고 상용삽입금속들(CIM-1, CIM-2) 역시 비교 평가하였다. 삽입금속들의 특성은 젖음성 시험, 전단강도 시험, 그리고 미세조직 관찰로서 나타내었다. 젖음성 시험에서 MIM-1과 CIM-1 삽입금속의 젖음각이 MIM-2와 CIM-2보다 크게 나타났고, MIM-1의 젖음각이 CIM-1보다 더 큰 값을 나타났지만 모든 경우 젖음각이 $25^{\circ}$보다 작았다. 삽입금속, MIM-1이 가장 높은 전단강도를 나타냈고, 그 값은 $2.29{\times}10^2MPa$로 측정되었다. 이 값은 상용 삽입금속의 값과 같거나 높은 것으로 나타났다. 삽입금속의 미세조직은 Cu-rich 초정영역과 Ag-rich 공정영역으로 구성되었다. MIM-1계로 만들어진 초경합금과 탄소강의 접합부는 일부 접합부 계면에 기공을 포함하지만 초정을 기지로 하는 안정적인 미세조직을 나타냈다.

• 설비공학논문집
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• 제21권10호
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• pp.583-589
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• 2009

Activated carbon has long been used in purification processes for indoor air quality. However, the bioaerosol removal by activated carbon is not often sufficient to be used in an air control devise. In order to overcome these problems, silver nano-particles have been proposed as an antibacterial agent on the surface of activated carbon. Silver or silver ions have been known for antimicrobial activities. In this study, bioaerosol generated by using an Escherichia coli culture was introduced to a lab-scale column packed with activated carbon (AC) and silver nano-particles attached to activated carbon (Ag-AC). E. coli was almost completely removed in the Ag-AC column, whereas bioaerosol penetrated through the AC column. To determine the antibacterial effect of different filter materials in a full-scale air-handling system, another experiment was conducted using a wind tunnel equipped with a heat exchanger and three filter materials including commercial fabric, AC and Ag-AC. It was found that E. coli proliferated on the surface of the heat exchanger after 5 days, which dramatically increased bioaerosol counts in the effluent air stream. The fabric filter could not control the increased bioaerosol and most of the E. coli penetrated the filter. The bacterial removal efficiency was found to be approximately 45% in the AC filter, while the antibacterial efficiency increased to 70% using the Ag-AC filter. Consequently, the Ag-AC filter can be an effective method to control bioaerosol and improve indoor air quality.

• 한국환경보건학회지
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• 제39권4호
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• pp.369-375
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• 2013

Objectives: This study was conducted to identify factors determining the toxicity of manufactured silver nano-particles (AgNPs) on aquatic organisms. Methods: For this purpose, we prepared several AgNPs with varied characteristics, including hydrodynamic size (nano-$^{ABC}Ag^{Cit}\;vs$-sized-$^{ABC}Ag^{Cit}$), impurities ($^{ABC}Ag$ stock vs $^{ABC}Ag$), and citrate capping ($^{ABC}Ag^{Cit}$), using a commercially available manufactured AgNP ($^{ABC}Ag$ stock). Acute tests were conducted using larval zebrafish (Danio rerioI). In addition, in order to determine the ecotoxicological potentials of various capping agents, toxicity tests were conducted with microbes, waterfleas, and fish for eight different capping agents that are used for NPs. Results: The toxicity of AgNPs in terms of 96 h fish $LC_{50}$ increased in the following order: $^{ABC}Ag$ stock < $^{ABC}Ag=^{ABC}Ag^{Cit}=nano-^{ABC}Ag^{Cit}$ < ${\mu}$-sized-$^{ABC}Ag^{Cit}$ < $AgNO_3$. After removing impurities by dialysis, 96 h $LC_{50}$ value decreased significantly from $126.6{\mu}g/L$ (95% confidence intervals [CI]: 107.0-146.2) ($^{ABC}Ag$ stock) to $78.6{\mu}g/L$ (CI: 72.7-84.8) ($^{ABC}Ag$). For ${\mu}$-sized-$^{ABC}Ag^{Cit}$ (ranging between 3.9 and 40.6 nm) and $^{ABC}Ag^{Cit}$ (40.6 nm and $9.1{\mu}m$), the 96 h $LC_{50}$ of the former ($43.9{\mu}g/L$, CI: 36.0-51.7) was approximately two-fold lower than that of the latter ($87.0{\mu}g/L$, CI: 73.5-100.3). Conclusions: In this study, we found that for acute lethality, the contribution of impurities and particle size was significant, but that of citrate was negligible.

• ETRI Journal
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• 제26권3호
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• pp.252-256
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• 2004

We formed silver nanocrystallites by the thermal decomposition of a $Ag^{+1}$-oleate complex, which was prepared by a reaction with $AgNO_{3}$ and sodium oleate in a water solution. The resulting monodispersed silver nanocrystallites were produced by controlling the temperature (290$^{\circ}$C). Transmission electron microscopic (TEM) images of the particles showed a 2-dimensional assembly of the particles with a diameter of $9.5{\pm}0.7nm$, demonstrating the uniformity of these nanocrystallites. An energy-dispersive X-ray (EDX) spectrum and X-ray diffraction (XRD) peaks of the nanocrystallites showed the highly crystalline nature of the silver structure. We analyzed the decomposition of the $Ag^{+1}$-oleate complex using a Thermo Gravimetric Analyzer (TGA) and observed the crystallization process using XRD.

• 동굴
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• 제76호
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• pp.15-17
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• 2006

[ $YBa_2Cu_3O_{7-{\delta}}$ ] superconductor films have been prepared on silver substrates by electrophoretic deposition. As silver does not react with $YBa_2Cu_3O_{7-{\delta}}$ compound and has little influence on its superconductivity, it is usually doped in $YBa_2Cu_3O_7$ to improve the strength of the material and eliminate micro cracks. It has been proved that Ag additive can lower the melting temperature of $YBa_2Cu_3O_{7-{\delta}}$ and act as linking bridge among $YBa_2Cu_3O_{7-{\delta}}$ particles, thus in this paper Ag doped $YBa_2Cu_3O_{7-{\delta}}$ thick films are prepared by electrophoretic co deposition. As there are only some referenced experience formula and models for co electrophoretic deposition and does not exist unified explanation, the behavior of Ag particles during co electrophoretic deposition is also studied.

• 한국재료학회지
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• 제8권12호
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• pp.1082-1089
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• 1998

$YBa_2$$Cu_3$$O_{7-y}$ (123) 초전도체에서 은 입자의 미세분산을 얻고자 말릭산을 사용한 발화합성과 고상반응법으로 123와 123-Ag 복합 초전도분말을 제조하였다. 발화합성분말을 원료로 사용할 시 마이크론 미만의 미세한 123 분말과 은 분말의 복합체를 얻을 수 있었다. 원료로 사용된 산화은($Ag_2O$) 분말은 발화합성과정 중금속 은으로 환원되었다. 원료분말에 첨가된 금속 은에 의한 반응 물질간의 확산 촉진으로 123상이 단시간내에 생성되었고 입자성장도 촉진되었다. 발화합성법으로 제조한 시편은 기계적 혼합공정으로 제조한 시편에 비해 은 입자들은 미세하게 분산시킬 수 있어서 초전도체의 임계전류밀도가 향상되었다.

• 한국지반환경공학회 논문집
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• 제17권2호
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• pp.5-11
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• 2016

다층벽탄소나노튜브(MWCNT)와 titanium(IV) butoxide(TNB) 그리고 silver nitrate($AgNO_3$)를 이용하여 졸-겔법으로 $MWCNT-TiO_2$ 복합체와 $Ag-MWCNT-TiO_2$ 복합체를 제조하였다. 복합체에서의 Ag의 분산 및 구조를 주사전자현미경(SEM)과 투과전자현미경(FE-TEM)으로 관찰하였다. X선 회절 분석기(XRD)를 이용하여 복합체의 패턴을 보았을 때 anatase 결정구조를 확인할 수 있었다. 에너지 분광 분석기(EDX)로 원소성분을 분석한 결과 주요 원소인 C, Ti, O 그리고 Ag가 확인되었다. $TiO_2$ 입자는 MWCNT에 균일하게 분산되었고, Ag 입자는 튜브 표면에 고정되었다. 또한 UV 조사 시간에 따른 메틸렌블루의 분해를 통하여 광촉매 활성평가를 하였다. $Ag-MWCNT-TiO_2$ 복합체는 $MWCNT-TiO_2$ 복합체보다 높은 광분해능을 보였다. Ag의 높은 전도성이 $MWCNT-TiO_2$ 복합체의 광활성을 향상 시킨다는 결과를 나타냈다.