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A Study on Synthesis and Dispersion of Silver Nano Particle Using Trisodium Citrate (Trisodium Citrate을 이용한 은 나노입자의 합성 및 분산성에 관한 연구)

  • Lee, Jong Jib
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.4
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    • pp.772-779
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    • 2016
  • Silver nanoparticles were prepared by reacting silver nitrate and trisodium citrate in an aqueous solution. Their size and shape were investigated by scanning electron microscopy (SEM). The synthesis was carried with different silver nitrate concentration, addition of TSC, solvent, surfactant, ultrasonication, and dispersing agent. With higher concentration of silver nitrate or TSC, the particles became large or agglomerated. The SEM results showed that the nanoparticles have spherical and pseudospherical shape with a narrow size distribution. The hydrophobic solvent did not affect the dispersibility, but the hydrophilic solvent enhanced it. The addition of HPMC surfactant caused the size to increase (50-100 nm) with non-uniform shapes and partial agglomeration. The dispersibility was significantly improved by ultrasonication for over 3 hours after the addition of a dispersing agent. Complete dispersion was achieved by adding the dispersant, and the nanoparticle sizes were as follows: 30-40 nm (BYK-182) < 42-78 nm (BYK-192) < 51-113 nm (BYK-142). The nanoparticles were 38.45-46.28 nm after the addition of 2-4 wt% TSC in 0.002 M silver nitrate solution.

Characteristics of Ag/AgCl Thin Film Reference Electrode in Urea Sensors (요소센서를 위한 은/염화은 박막 기준전극의 특성)

  • Jin, Joon-Hyung;Kang, Chul-Goo;Kang, Moon-Sik;Min, Nam-Ki;Hong, Suk-In
    • Proceedings of the KIEE Conference
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    • pp.1911-1913
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    • 2001
  • 전위차 측정형 바이오 센서는 기준전극에 대한 센서 전극의 전기화학적 전위를 정확하게 측정하여야 하므로 기준전극의 안정성이 매우 중요하다. 기준전극의 전위는 전해질 용액 내의 염소 음이온 농도에 영향을 받으나 다행히도 혈액 내의 염소 음이온 농도는 거의 변화가 없으므로 혈액 속에서의 은/염화은 기준전극의 전위도 거의 변화가 없다. 본 연구에서는, 사진석판 (Photolithography) 공정을 이용하여 실리콘 표면 및 다공질 실리콘 표면에 은/염화은 박막 기준전극을 제작하고 시료 용액에서의 drift, 안정성, 재현성 등에 대한 특성을 고찰하였고, SEM, AES, EDX 스펙트럼 등을 이용하여 전극의 표면을 분석하였다. 시료 용액의 염소 음이온 농도를 $10^{-4}$M에서 1M까지 변화시켜가며 기준 전극의 전위를 측정한 결과 약 50mV/pCl의 기울기를 얻었으며 이것은 Nernst식을 잘 따르는 결과이다.

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수산화인회석을 지지체로 사용한 은 나노 입자의 합성과 촉매 활성 연구

  • Pyo, Eun-Ji;Gwon, Gi-Yeong
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.164.1-164.1
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    • 2016
  • 본 연구에서 지지체로 사용된 단결정 형태의 수산화인회석(Hydroxyapatite)은 칼슘과 인산염으로 구성된 무기물이다. 염기 조건 (10 M NaOH)에서 수열합성법 (Hydrothermal method)을 이용하여 단결정 형태의 수산화인회석을 합성하였다. 합성된 단결정 수산화인회석의 표면에 이온 교환 반응을 통하여 은 원자를 도입하였으며, 아르곤 및 수소 기류 (96% Ar, 4% $H_2$) 조건에서 가열하는 온도를 조절하는 것으로 은 나노 입자를 생성시켰다. 합성된 샘플은 XRD 패턴 및 TEM 이미지 분석을 통하여, 수산화인회석의 합성 및 은 나노 입자가 형성된 것을 확인하였다. 합성된 샘플을 유기 반응 촉매로 사용하여 여러 가지 알코올 (1차, 2차 알코올)의 산화 반응에 응용하였으며, UV-Visble light 영역에서의 메틸렌 블루 분해 반응 실험에 광촉매로서 사용하였다.

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농업기술 - UCMT농법(農法)(유시엠티 농법) (II)

  • Lee, Yun-Gu
    • 농업기술회보
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    • v.46 no.5
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    • pp.30-34
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    • 2009
  • 하농(下農)은 잡초를 기르고 중농(中農)은 작물을 기르고 상농(上農)은 땅을 기른다. 좋은 땅의 조건은 물리학적 조건과 생물학적 그리고 화학적 조건을 고루 갖추어야 한다.

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Statistical Analysis for Silver Nanoparticle Synthesis Using Ionic Liquid (이온성액체 기반 은 나노입자 합성을 위한 통계적 실험 분석)

  • Lee, Kil Woo;Yoo, Kye Sang
    • Applied Chemistry for Engineering
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    • v.29 no.1
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    • pp.77-80
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    • 2018
  • Silver nanoparticles with various sizes were synthesized using ionic liquids. In order to conduct more efficient research, experimental methods and results were analyzed statistically. First, effects of five different parameters including the reaction time, temperature, NaOH concentration, reducing agent and ionic liquid amount on the size of silver particles were investigated. As a result, the effects of time and temperature were negligible. The experimental conditions for the other three factors were then statistically constructed. From XRD analyses, the particles synthesized under all conditions had a pure silver crystal structure. Sizes of the synthesized silver particles were also analyzed by HR-SEM. In the three synthetic conditions, NaOH concentration had the greatest influence on determining the size of silver particles and the reducing agent concentration was relatively minute. Synthesis conditions of silver particles with various sizes were presented by using statistical methods with respect to NaOH and ionic liquids. In addition, the sizes of silver particles according to three experimental conditions were derived by the mixture method.

The effect of temperature and light on anthocyanin synthesis in Glehnia littoralis Fr. Schm. (갯방풍의 Anthocyanin생성에 미치는 온도 및 광의 영향)

  • 부희옥
    • Korean Journal of Plant Resources
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    • v.8 no.2
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    • pp.135-141
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    • 1995
  • The experiment was carried out to clarify the effects of air temperature, light exposure and UV light on the growth and anthocyanin syntheses of Glehnia littoralis Fr. Schm. The major pigment of purfied aglycone of Glehnia littoralis Fr. Schm. was identified as cyanidin by TLC and HPLC analysis. The anthocyanin Syntheses was promoted at low temperature and in the treatment of light exposure (12hrs a day) for 4-6 days after shading. The plants grown under UV-cut film had less anthocyanin content those tose under UV-transmission film.

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Study on Osteological Characteristics of Acanthorhodeus gracilis (가시납지리 (Acanthorhodeus gracilis)의 골격학적 연구(硏究))

  • Kim, Ik-Soo;Kim, In-Ja
    • Korean Journal of Ichthyology
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    • v.10 no.2
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    • pp.231-240
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    • 1998
  • The characteristics of cranium, vertebral column and fin supports of Acanthorhodeus gracilis were examined. The fish did not have a fontanell in cranium nor process of supraethmoid. It had double orbitosphenoids and a basioccipital process developed from anterior portion of basioccipital. It had a high and triangular dorsal process on supraoccipital. In the urohyal, hypohyal attachment was bifurcated and horizontal and vertical plate were in an elongated rhombus shape with posterior edge pointed. It had teeth of 1-rowed, 5/5 and 4 free teeth. The fish did not have a coracoid foramen on shoulder girdle. It does not have a uroneural on ural centrum. It had a long and slender posterior process of pelvic bone. It had a large and flat supraneural. The fish had 14 or 15 interneural spines, of which the 1st, 2nd, 3rd and 4th had single basiosts and the rest had double basiosts. It had 11 or 12 interhemal spines, of which the 1st, 2nd, 3rd and 4th had single basiosts and the rest had double basiosts.

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Reflectivity characteristics of Ag nano-crystals grown by electroless plating (무전해 도금에 의해 성장되어진 은 나노결정의 반사율 특성)

  • Kim, Shin-Woo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.23 no.5
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    • pp.218-223
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    • 2013
  • In this study, the reflectivity characteristics of Ag nano-coating grown by electroless plating were investigated in order to use as the reflecting plate of BLU (Back Light Unit) in the LCD (Liquid Crystal Display) or LED (Light Emitting Diode) display equipment. The microstructure of Ag nano-coating was polycrystalline nano-structure that consisted of Ag nano-crystals to be reduced and precipitated, and the size of reduced nano-crystals increased as the thickness of nano-coating increased. The reflectivity of Ag nano-coating in the visible light decreased as the thickness of nano-coating increased and the reduction of reflectivity was more severe in the short wavelength region of visible light. The decrease of reflectivity was closely related to the size of Ag nano-crystal and was thought to be due to the larger surface roughness of larger nano-coating thickness. Therefore, the finer Ag nano-crystals and thinner nano-coating thickness could be favorable for the higher reflectivity of Ag nano-coating grown by electroless plating.

Preparation of Silver Nanoparticles by Chemical Reduction-Protection Method Using 1-Decanoic Acid and Tri-n-octylphosphine, and their Application in Electrically Conductive Silver Nanopaste (1-Decanoic Acid와 Tri-n-octylphosphine을 이용하여 화학적 환원법으로 제조된 은 나노입자의 특성 및 전기적 전도체 적용)

  • Sim, Sang-Bo;Bae, Dong-Sik;Han, Jong-Dae
    • Applied Chemistry for Engineering
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    • v.27 no.1
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    • pp.68-73
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    • 2016
  • Silver nanoparticles were prepared by chemical reduction-protection method using 1-decanoic acid and tri-n-octylphosphine as surfactants, and using $NaBH_4$ as a reducing agent. The silver nanoparticles were also studied for their formation, structure, morphology and size using UV-Visible spectroscopy, XRD, TEM and SEM. Further the viscosity of the silver paste and the surface resistance of the silver metal film produced by screen coating onto a PET film were investigated. Well dispersed and quasispherical silver nanoparticles with the size of 10-200 nm were obtained under the optimal molar ratio of $NaBH_4/AgNO_3=1:5$. The surface resistance of silver metal film coated on the PET film made with the silver nanoparticles under the optimal molar ratio showed a minal value of $41{\mu}{\Omega}/cm^2$.

Separation of Gold and Silver from Diverse Solutions by Solvent Extraction (다양한 용액으로부터 용매추출에 의한 금과 은의 분리)

  • Xing, Weidong;Lee, Manseung
    • Journal of the Korean Institute of Resources Recycling
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    • v.26 no.5
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    • pp.3-11
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    • 2017
  • Solvent extraction is an important process to recover pure gold and silver from various leaching solutions. The present work reviews the aqueous chemistry and solvent extraction separation of gold (I, III) and silver (I) from several leaching systems such as cyanide, thiocyanate, thiosulfate, thiourea and chloride medium. The extraction and separation behavior of gold (I, III) and silver (I) by various single and mixtures was compared on the basis of extraction reaction and the selectivity from these mediums. The chloride medium is recommended for the separation of gold and silver by solvent extraction in terms of extraction and stripping efficiency.