• Bulletin of the Korean Chemical Society
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• 제7권3호
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• pp.190-193
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• 1986

The structure of partially $Ag^+$-exchanged zeolite 4A, $Ag_{7.6}Na_{4.4}-A$, vacuum dehydrated at $370^{\circ}C$, has been determined by single-crystal x-ray diffraction techniques in the cubic space group, Pm3m (a = 12.311(1)${\AA}$) at $24(1)^{\circ}}C$. The structure was refined to the final error indices $R_1$ = $R_2$ (weighted) = 0.064 using 266 independent reflections for which $I_0$>$3{\sigma}(I_0)$. Three $Na^+$ ions occupy the 3 8-ring sites, and the remaining ions, 1.4 $Na^+$ and 6.6 $Ag^+$, fill the 8 6-ring sites; each $Ag^+$ ion is nearly in the [111] plane of its 3 O(3) ligands, and each $Na^+$ ion is 0.9${\AA}$ from its corresponding plane, on the large-cavity side. One reduced silver atom per unit cell was found inside the sodalite unit. It was presumably formed from the reduction of a $Ag^+$ ion by an oxide ion of a residual water molecule or of the zeolite framework. It may be present as a hexasilver cluster in 1/6 of the sodalite units, or, most attractively among several alternatives, as an isolated Ag atom coordinated to 4 Ag ions in each sodalite unit to give $(Ag_5)^{4+}$, symmetry 4mm.

• 한국의류학회지
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• 제32권6호
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• pp.947-958
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• 2008

은나노를 이용한 드럼식 세탁기로 세탁한 경우 발생되는 세탁물의 변퇴색 및 오염현상을 관찰하기 위해 이와 유사한 세탁원리를 갖는 론더로메타를 이용하여 그 결과를 알아보았다. 반응성염료로 염색한 면직물과 분산염료로 염색한 폴리에스터 직물을 세탁포로 하고, 첨부 백포로 면, 폴리에스테르, 나일론을 이용하여, 세탁온도, 세탁액비, 세제 농도, 세탁용수를 변화시켜 세탁물의 염색견뢰도를 관찰하였고, 은물로 세탁한 경우 세탁물로의 은침착 여부를 관찰하였다. 그 결과, 세탁조건에 따른 염색포의 변색은 크지 않았으나, 세탁온도가 높고, 세탁 액비가 낮은 조건에서 첨부 백포로의 오염이 크게 나타났고, 특히 나일론 첨부 백포로의 오염이 컸다. 세제농도와 세탁용수는 염색견뢰도에 큰 영향을 미치지 않았다. 세탁용수를 달리하여 세제없이 백포만 반복 세탁한 경우, 은물로 세탁한 면, 나일론은 수돗물로 세탁한 경우보다 백도가 약간 낮게 나타났으며, 정량분석 결과 세탁물에 은화합물이 침착되었음이 확인되었다.

• Journal of Oral Medicine and Pain
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• 제42권4호
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• pp.102-108
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• 2017

Purpose: Many metal ions released from dental casting alloys have been reported to influence the intraoral symptoms of oral lichen planus (OLP) and burning mouth syndrome (BMS). The aim of this study was to investigate the relationship between salivary metal ion levels and the prosthetic duration as well as to evaluate the time-dependent morbid effects of metal ions in OLP and BMS patients. Methods: Three study groups consist of the following subjects respectively: 17 OLP patients, 12 BMS patients, and 12 patients without oral symptoms. The salivary concentrations of 13 metal ions (copper, cobalt, zinc, chromium, nickel, aluminum, silver, iron, titanium [Ti], platinum, tin, palladium, and gold) were measured by Laser Ablation Microprobe Inductively coupled Plasma Mass Spectrometry. Results: The Ti ions had statistically significant differences among the groups with a prosthetic duration of less than 5 years. There were no significant differences between all ion levels among the groups wearing dental cast alloys for over 5 years. In the BMS group, the level of Ti ions in patients with prosthetic restorations less than 5 years old were significantly high (p<0.05). Conclusions: In the BMS group, 3-60 months during which salivary Ti levels were higher were matched with the duration of burning symptoms ($15.6{\pm}17.1months$). Furthermore, Ti ions were statistically high in the oral cavity of BMS patients fitted with dental casting alloys for 5 years. These results suggest that Ti ions released from dental implants and oral prostheses could attribute to burning sensation of BMS.

• Environmental Analysis Health and Toxicology
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• 제30권
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• pp.3.1-3.6
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• 2015

Objectives This study aims to evaluate the size-dependent toxicity of spherical silver nanoparticles (Ag NPs) to an endemic benthic organism, Glyptotendipes tokunagai. Methods Ag nanoparticles of three nominal sizes (50, 100, and 150 nm) capped with polyvinyl pyrrolidone (PVP-Ag NPs) were used. Their physicochemical properties, acute toxicity (48 hours), and bioaccumulation were measured using third instar larvae of G. tokunagai. Results The aggregation and dissolution of PVP-Ag NPs increased with exposure time and concentration, respectively, particularly for 50 nm PVP-Ag NPs. However, the dissolved concentration of Ag ions was not significant compared with the median lethal concentration value for $AgNO_3$ (3.51 mg/L). The acute toxicity of PVP-Ag NPs was highest for the smallest particles (50 nm), whereas bioaccumulation was greatest for the largest particles (150 nm). However, larger PVP-Ag NPs were absorbed and excreted rapidly, resulting in shorter stays in G. tokunagai than the smaller ones. Conclusions The size of PVP-Ag NPs significantly affects their acute toxicity to G. tokunagai. In particular, smaller PVP-Ag NPs have a higher solubility and stay longer in the body of G. tokunagai, resulting in higher toxicity than larger PVP-Ag NPs.

• 한국결정학회지
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• 제11권1호
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• pp.28-33
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• 2000

The slow of 2,3-bis(2-pyridyl)pyarzine(bpp) with Ag(CF₃CO₂) produces crystalline product suitable for X-ray crystallography. Crystallographic characterization of the crystal (C/sub 32/H/sub 20/-F/sub 6/N/sub 8/O₄Ag₂: triclinic P1, a=8.518(5)Å, b=9.546(2)Å, c=10.632(1)Å, α=81.11(1)°, β=87.61(3)°, γ=75.66(3)°, V=827.5(5)ų, Z=1, R=0.0431) has provided that the complex is a cyclic dimer [Ag(bpp)(CF₃CO₂)]₂. Each bpp ligand connects two tetrahedral silver(I) ions in a tridentate mode (Ag-N, 2.26()-2.43(2)Å), and the trifluoroacetato anion is bonded to each silver(I) atom in a monodentate fashion (Ag-O, 2.38(1); 2.39(2) Å). The skeletal cyclic dimer is stable up to 212℃, and drastically decomposes around this temperature.

• 공업화학
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• 제5권6호
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• pp.957-966
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• 1994

HZSM-5와 Ag 이온으로 교환된 ZSM-5를 촉매로 사용하여 부탄과 1-부텐으로부터 방향족 화합물로의 전환반응을 수행하였다. 방향족 탄화수소의 수율은 HZSM-5 내에 Ag 이온을 도입함으로써 현저하게 증가하였다 Ag 이온들은 출발원료인 탄화수소의 탈수소 촉매로서 작용하였다. 부탄과 1-부텐의 탈수소 과정에서 생성된 수소는 $Ag^+$ 이온을 Ag 금속으로 환원시킴과 동시에 산점의 형성을 유발하였다. Ag의 담지량이 다른 ZSM-5를 촉매로 사용하여 1-부텐의 전환반응을 수행하고, 이들 촉매의 산점특성 변화에 따른 효과를 검토하였다.

• 한국응용과학기술학회지
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• 제37권5호
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• pp.1100-1105
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• 2020

본 연구는 기계화학적 활성화 된 스카치테이프가 금속 이온 수용액에서 유발하는 자발적 금속 나노입자 필름 형성의 구동력과 그 크기를 전기화학적 방법으로 분석했다. 은 필름이 형성된 테이프를 질산에 녹이고, 완충용액과 섞어 전기화학 측정용 샘플을 준비했다. 양극 벗김 전압전류법의 피크 신호를 통해, 은 입자의 자발적 환원에 소모된 전하량을 측정했다. 이를 검정 곡선에 대입하여, 환원된 은의 양을 구했다. 그 결과 은의 양이 선행 연구 대비 10⁶배 많은 점, 수용액에서 전하를 가진 이온들의 짧은 수명을 참고하여, 자발적 반응의 구동력을 라디칼로 결론 냈다.

• 대한치과보철학회지
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• 제27권1호
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• pp.31-47
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• 1989

The purpose of this study was to evaluate the chemical bond strength of successively recast Pd-Ag ceramic alloys with porcelain and to investigate changes of quantity of trace elements at the metal-porcelain interface. Porcelain was fired as usual manner on the each successively recast specimen. Rectangular planar shear test was performed and bond strength was measured by Instron universal testing machine. Diffusion of trace elements at the each interface was observed by ESCA (Electron Spectroscopy for Chemical Analysis). The obtained results were as follows : 1. Chemical bond strength was significantly decreased after second recasting. But in case of first recasting, there was no significant decrease of bond strength statistically (p<0.05). 2. Bond strength was not significantly decreased in each generation, when fifty percents new alloy was added (p<0.05). 3. Ag, Sn and In were observed at the porcelain interface. But Pd was not observed. 4. The quantity of Ag, In ions were progressively increased at the metal-porcelain interface as the casting was repeated. Silver ion was most significantly increased.

• Bulletin of the Korean Chemical Society
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• 제11권3호
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• pp.200-205
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• 1990

Chemically modified electrodes(CMEs), based on 2-imino-1-cyclopentane-dithiocarboxylic acid (icdc) containing carbon paste, have been characterized using cyclic voltammetric techniques. Ag(I) was chemically deposited on the CMEs, and voltammograms were obtained with the electrode in a separate buffer solution. The CME surface can be regenerated with exposure to acid and reused for deposition. In 10 deposition/measurement/regenerate cycles, the linear response have been reproduced up to $1{\times}10^{-6}$ M in linear sweep voltammetry and 1${\times}$10-8 M in differential pulse voltammetry with relative standard deviation of 5.2% and 12.4%, respectiveiy. The sensitivity increased with deposition time and scanning rate, and detection limit was $1{\times}10^{-7}M\;and\;1{\times}10^{-9}M$ at 20 minutes deposition in the linear sweep voltammetry and differential pulse voltammetry, respectively. The presence of some metal ions does not influence the silver ion response. Satisfactory results were obtained for the analysis of the silver ion for a variety of reference materials without interference of Hg ion at the condition of pH = 5-6.

• 대한화학회지
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• 제38권9호
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• pp.621-627
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• 1994

$Ag^{+}$ 이온과 $Ca^{2+}$ 이온으로 치환된 제올라이트 $A(Ag_{12-2x}Ca_{x}-A$, x=2 및 3)$를 탈수하고 $250^{\circ}C$, 0.15torr의 Cs 증기로 처리한 결정구조를 X-선 단결정 회절법으로 입방공간군 Pm{\bar\3m(a=12.344(2){\AA}$/ 과 12.304(2) $\AA$)을 사용하여 해석하였다. 이들 구조에서 최종 오차인자 값 Rw는 I > $3\sigma(I)$인 180 및 179개의 반사를 이용하여 0.091 및 0.093까지 정밀화시켰다. 이들 구조에서 Cs종은 네 개의 서로 다른 결정학적 자리에 위치하였다. 단위세포당 세 개의 $Cs^{+}$ 이온은 8-링 중심에 위치하여, 6.81~7.14개의 $Cs^{+}$이온은 큰 동공내의 3회 회전축상 6-링상에 위치하고, 1.83~2.03개의 $Cs^{+}$ 이온은 소다라이트 동공내의 3회 회전축상에 위치하고, 0.66~0.71개의 $Cs^{+}$이온은 4-링에 위치하였다. 또한 4.12~4.27개의 Ag 원자는 큰 동공 중심 가까이에 위치하였다. 이들 구조에서 단위세포내에 과잉으로 흡착된 Cs원자들은 3회 회전축상 위에 놓여 있는 $Cs^{+}$이온과 결합하여 선형의 $(Cs_4)^{3+}$ 클라스터를 형성하고 있었다. 또 $Cs^+$ 이온이 8-링을 차지하고 있어서 은 원자가 구조 밖으로 나오지 못하게 막고 있었다. 이들 원자는 큰 동공 중심에서 hexasilver 클라스터를 형성하고 있었으며, 14개의 $Cs^{+}$ 이온과 배위하여 안정화되어 있었다.