• Journal of the Korean Wood Science and Technology
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• 제51권6호
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• pp.470-480
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• 2023

This study aimed to develop a sound-absorbing composite using sugarcane bagasse (SB) and coffee silver skin (CS) as raw materials. The composite boards were manufactured by bonding the fibers with Melamine Urea-Formaldehyde adhesive, ensuring a consistent thickness of 30 mm. Various densities were employed, namely 380, 450, and 520 kg/m³. The samples were fabricated with different fiber ratios, including SB100%, SB75% with CS25%, and SB50% with CS50%. The sound absorption coefficient (SAC) and noise reduction coefficient (NRC) were measured using the impedance tube method within a frequency range of 63-6,300 Hz. The experimental results revealed that the mixing ratio of CS exerted a notable influence on enhancing the SAC, while the density of the composite board exhibited a significant impact on increasing both the SAC and NRC. Among the densities tested, the optimal value was observed at 520 kg/m³, yielding a SAC value of 0.65 at a frequency of 1,000 Hz and an NRC value of 0.55 for the SB50-CS50 composite plate. These findings underscore the importance of considering the CS mixing ratio and composite board density when aiming to optimize sound absorption properties.

• 한국의류학회지
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• 제34권5호
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• pp.775-783
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• 2010

This study examines the dyeability, light fastness, washing fastness, and the antibacterial activity of chitosan and nano silver composite non-woven fabrics dyed with an extracted solution from Chrysanthemum Indicum Linn. The results show that an increase in the chitosan and nano silver percentage resulted in an increase in the $a^*$ values and $b^*$ values; however, the $L^*$ values decreased in the undyed condition. ${\Delta}E$ values of chitosan and nano silver composite non-woven fabrics were higher than cotton 100% non-woven fabrics in the dyed condition with an extracted solution from Chrysanthemum Indicum Linn, and mordant treatments influenced the chrominance change. In the dyed condition with an extracted solution from Chrysanthemum Indicum Linn, an increase in the percentage of chitosan and nano silver resulted in an increase of the K/S values. The dyeability of chitosan and nano silver composite non-woven fabrics increased by mordant treatments. The light fastness and washing fastness of the mordanted non-woven fabrics were better than the non-mordanted. For the antibacterial activity, the bacterial reduction rate of chitosan and nano silver composite non-woven fabrics was 99.9% to Staphylococcus aureus and Klebsiella pneumoniae.

• 한국분무공학회지
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• 제20권1호
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• pp.53-58
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• 2015

In this study, we prepare the Ag nanofluids synthesized by the chemical reduction method and measure the extinction coefficient of those nanofluids at a wavelength of 632.8 nm. The Ag nanofluids are synthesized by the chemical reduction method using silver nitrate ($AgNO_3$) and sodium borohydride ($NaBH_4$) in water and ethylene glycol (EG). For stable dispersion of Ag particles in the base liquids, polyvinyl pyrrolidone (PVP) is added as a surfactant. The extinction coefficient of manufactured Ag nanofluids is measured by an in-house developed measurement system at the wavelength of 632.8 nm. The results show that the extinction coefficient of water-based and EG-based Ag nanofluids is linearly increased with respect to the particle loadings. Moreover, it is shown that the extinction coefficient of EG-based Ag nanofludis is higher than that of water-based Ag nanofluids. Finally we compare the experimental results with both the Maxwell-Garnett model and Rayleigh scattering approximation model, and they demonstrate that the Rayleigh scattering approximation model is reasonably predict the extinction coefficient of Ag nanofluids using hydraulic diameter of silver nanoparticle.

• 한국표면공학회지
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• 제8권1호
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• pp.1-9
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• 1975

The crorosion film of gilt bronz, silver and iron objects, which were excaved from Ancient Tomb of Silla Dynasty, was removed by the electrolytic reduction process. These metallic objects were mainly investigated for microstructure, designs and gilting film etc. Most iron objects might be made by hot forging process. The cold extrusion technique might be used for gold and silver objects, in addition to an amalgam method might be applied for the gilting Au film on Cu-alloy surface. For the gilting on glass surface, first, a Cu alloy was cladded on glass , next, Au-film was obtained on the Cu-ally by the amagum method.

• Bulletin of the Korean Chemical Society
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• 제7권1호
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• pp.55-58
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• 1986

Analytical capability of surface-enhanced Raman scattering has been evaluated. Silver films prepared by homogeneous chemical reduction were used as the substrate. Detection limits for p-nitrobenzoic acid, thiophenol and rhodamine 6G were around $10{\sim}100\;pg$.

• 한국전기전자재료학회논문지
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• 제11권9호
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• pp.727-732
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• 1998

Ag-deposited graphite powder was prepared by a chemical reduction method of metal particles onto graphite powder. X-ray diffraction observation of Ag-deposited graphite powder revealed that silver existed in a metallic state, but not in an oxidized one. From SEM measurement, ultrafine silver particles were highly dispersed on the surface of graphite particles. Cylindrical lithium ion secondary battery was manufactured using Ag-deposited graphite anodes and $LiCoO_2$ cathodes. The cycleability of lithium ion secondary battery using Ag-deposited graphite anodes was superior to that of original graphite powder. The improved cycleability may be due to both the reduction of electric resistance between electrodes and the highly durable Ag-graphite anode.

• 폴리머
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• 제34권2호
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• pp.144-149
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• 2010

Ag/polystyrene(PS) 나노복합체를 110 $^{\circ}C$의 가열법에 의하여 silver 2-ethylhexylcarbamate(Ag-CB) 복합체의 환원과 동시에 라디칼 중합을 진행하여 제조하였다. 또한, 이러한 전통적인 가열법과는 대조적으로 마이크로파를 조사하여 스티렌 단량체의 중합이 진행됨이 없이 은 나노입자가 잘 분산된 콜로이드 스티렌 용액을 제조할 수 있었다. 이렇게 단지 마이크로파를 조사하여 은 나노입자를 제조하는 방법은 반응기 내의 전체 용액 속에서 균일하고 빠르게 진행되어 매우 입자가 작고 균일한 은 나노콜로이드 용액을 제조할 수 있었다. 또한, 연속적으로 얻어진 은 나노입자를 포함하는 단량체 용액을 라디칼 중합시킴으로써 PS 고분자 매트릭스에 은 나노입자가 잘 분산된 Ag/PS 나노복합체를 얻을 수 있었다. Ag/PS(0.1/100) 나노복합체는 Ag/PS(4.0/100)를 마스터배치로 사용하여 용융-혼합 방법에 의하여 성공적으로 제조할 수 있었으며 그러한 나노복합체를 UV-VIS spectroscopy, TEM, 그리고 XRD를 이용하여 확인하였다.

• 자원리싸이클링
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• 제14권6호
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• pp.21-27
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• 2005

국내 은 함유 폐자원의 고부가가치 제품화를 위한 연구의 일환으로써 sodium formaldehydesulfoxy와 ascorbic acid를 각각 환원제로 사용한 Ag 나노분발의 제조실험을 수행하였다. Ag수용액은 질산은을 소정 농도로 증류수에 용해시켜 사용하였으며, Ag미립자의 응집방지를 위한 분산제로는 Tamol NN8906, PVP, SDS 및 caprylic acid를 각각 사용하었다. 환원반응을 통하여 제조한 Ag 미립자는 입도분석기 및 TEM측정을 통하여 morphology와 평균입도를 측정하였다. sodium formaldehydesulfoxylate 에 의한 은의 환원을 위해서는 이론치의 1.4배를 첨가해 주어야 하는 것으로 나타났으며, ascorbic acid와는 달리 생성된 Ag 입자가 너무 크게 성장하는 문제점이 있었다. 분산제에 따른 Ag 입자의 특성을 살펴본 결과, Tamol 및 PVP를 사용한 경우에는 bimodal distribution을 보였으나, SDS 와 caprylic acid의 경우에는 수십 nm에서 $100{\mu}m$에 이르는 매우 broad한 입도분포를 보였다.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 추계총회 및 연구발표회 초록집
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• pp.85.2-85
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• 2003

• Korean Chemical Engineering Research
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• 제46권4호
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• pp.756-763
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• 2008

본 연구에서는 잉크젯용 전도성 금속 나노 잉크 개발을 목표로 통계적인 실험과 분석을 진행하여 재현성 있는 고품질의 은 나노 입자를 합성할 수 있는 기술을 개발하고자 하였다. 은 나노 입자는 상용 수계분산제 Daxad19를 이용한 용액 환원침전법을 통해 0.3 M의 고농도로 합성되었다. 합성에 주요한 영향을 주는 6개의 인자를 선정한 후 실험 계획법(Design-of-experiment)을 통해 실험을 수행하였다. 합성된 은 입자는 SEM, TEM, UV-Visible 등의 분석법을 이용하여 입자크기 및 분포와 분산도 등을 측정하였으며 통계 프로그램인 Minitab으로 이를 최적화하였다. 통계적인 실험계획 및 분석은 2차 부분요인분석법(2k-fractional factorial design)과 반응표면분석법인 박스-벤켄법(Box-Behnken design)으로 진행하였다. 이를 통한 합성 최적화로 평균입경 $30nm{\pm}10%$를 가진 구형의 은 나노 입자를 합성하였다. 또한 본 연구에서는 실험 결과 해석을 통해 환원침전법에서의 입자크기 및 형상 제어의 방식도 실험적으로 밝혀냈다.