• 대한화학회지
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• 제12권2호
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• pp.47-50
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• 1968

Dowex $1{\times}4$ 陰이온 交煥樹指를 二段階(높이:下段 22cm, 上段 3cm, 直經 1.5cm)로 充塡하여 비스머스 金屬中에 들어있는 不純物인 Pb(II), Ag(I), Cu(II)를 7.5M 鹽酸으로, 그리고 Zn(II), Fe(III)를 0.5M 鹽酸으로 分離하고 上段에 남아있는 Te(IV)은 2M NaOH 용액으로 容出하고 아직도 上段에 남아있는 Au(III)는 樹脂를 태워서 分離하였다. 또 한가지 方法은 같은 樹脂를 10cm 높이로 一段階의 管에 充塡하여 0.5M 鹽酸으로 Pb(II), Ag(I), Cu(II), Fe(III), Zn(II)를 함께 容出하여 비스머스 中에서 分離하였다. 分離된 모든 不純物은 比色法으로 定量하였다.

• 한국재료학회지
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• 제29권1호
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• pp.37-42
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• 2019

This study investigates Ag coated $Cu_2O$ nanoparticles that are produced with a changing molar ratio of Ag and $Cu_2O$. The results of XRD analysis reveal that each nanoparticle has a diffraction pattern peculiar to Ag and $Cu_2O$ determination, and SEM image analysis confirms that Ag is partially coated on the surface of $Cu_2O$ nanoparticles. The conductive paste with Ag coated $Cu_2O$ nanoparticles approaches the specific resistance of $6.4{\Omega}{\cdot}cm$ for silver paste(SP) as $(Ag)/(Cu_2O)$ the molar ratio increases. The paste(containing 70 % content and average a 100 nm particle size for the silver nanoparticles) for commercial use for mounting with a fine line width of $100{\mu}m$ or less has a surface resistance of 5 to $20{\mu}{\Omega}{\cdot}cm$, while in this research an Ag coated $Cu_2O$ paste has a larger surface resistance, which is disadvantageous. Its performance deteriorates as a material required for application of a fine line width electrode for a touch panel. A touch panel module that utilizes a nano imprinting technique of $10{\mu}m$ or less is expected to be used as an electrode material for electric and electronic parts where large precision(mounting with fine line width) is not required.

• 한국물환경학회지
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• 제30권3호
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• pp.298-303
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• 2014

We measured by electrochemical method for TRC (total residual chlorine) in ocean. From the results of Au electrode used for working electrode through cyclic voltammetry test, we obtained charge in voltage ranged from 0.0V-1.0V, and analyzed correlations of charge for TRC. Reduction peak TRC was investigated to be approximately 0.65 V vs. Ag/AgCl, and in the case that salt concentrations and temperatures in ocean appeared different, charge was analyzed for being different in the same TRC. However, in the case that each condition was constant, charge was measured at highly correlations for TRC.

• 대한화학회지
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• 제55권1호
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• pp.63-69
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• 2011

이 작업은 수송체로서 N,N'-bis(2-hydroxybenzyl)-1,3-diaminopropane (L1)과 N,N'-bis(2-hydroxybenzyl)-2,2-dimethyl-1,3-diaminopropane (L2)에 기초한 $Ag^+$ 이온-선택 전극의 제조, 개발 그리고 전압반응에 대해 토의한다. $Ag^+$에 대하여 L1에 기초한 전극은 58.7 mV/dec에 도달하는 안정한 Nernst에 가까운 기울기와 $1.0{\times}10^{-6}M$의 검출한계를 갖는 등급의 최소 다섯가지 순서의 선형범위에서 최적의 전압 반응 특징을 보이는 것을 나타낸다. 제안된 전극은 다른 테스트한 양이온과 비교하여 $Ag^+$에 우위의 선택성을 보였다. 훌륭한 전압 분석적 특징은 중요한 진짜 샘플에서 은의 순도분석의 성공적인 응용을 이끌 것이다. 그리고 그것은 제안된 $Ag^+$-ISE가 측정 능력의 중요한 진보를 보여준다는 것을 나타내고 있다. 그러나 L2에 기초한 전극에 대해서는, 약한 전압 반응 특징들이 전체 실험 과정에서 관측되었다.

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2249-2252
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• 2011

Two new carborane complexes containing closo- or nido-carborane diphosphine ligands with the formula: complex $[Hg(7,8-(PPh_2)_2-7,8-C_2B_9H_{10})_2]$ $CH_2Cl_2$ (1) and $[Ag_2({\mu}-Cl)_2(1,2-(P^iPr_2)_2-1,2-C_2B_{10}H_{10})_2]$ (2) have been synthesized and characterized by elemental analysis, 1H and 13C NMR spectroscopy and X-ray structure determination. The X-ray structure analyses revealed that the carborane diphosphine ligand was degraded from closo-1,2-$(PPh_2)_2-1,2-C_2B_{10}H_{10}$ to nido-[$7,8-(PPh_2)_2-7,8-C_2B_9H_{10}]^-$ in complex 1, while the closo nature of the starting ligand $1,2-(P^iPr_2)_2-1,2-C_2B_{10}H_{10}$ was retained in complex 2. In either of the two complexes, the carborane diphosphine ligand was coordinated bidentately to the Hg(II) or Ag(I) center through its two phosphorus atoms, therefore forming a five-member cheating ring between the carborane ligand and the metal center. The coordination geometry of the metal atom is distorted tetrahedron formed by $P_4$ unit in complex 1 and $P_2Cl_2$ unit in complex 2, respectively.

• Advances in materials Research
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• 제9권3호
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• pp.171-187
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• 2020

The microstructural evolution of different compositions of Mg-Sn alloys (30%Sn-70%Mg, 40%Sn-60%Mg and 50%Sn-50%Mg) is studied at first to understand the changes observed with change in tin content and deformation conditions. The Mg₂Sn phase increases with increase in tin content and a significant substructure development is found in 50%Sn-50%Mg alloy. The above observation led to further deformation studies on Mg₂Sn based thermoelectric materials with higher tin percentage. The microstructure in terms of Electron backscatter diffraction (EBSD)measurements is studied in detail followed by the determination of thermoelectric properties i.e., Seebeck coefficient and electrical conductivity for both as cast and extruded Mg_(2+x)Sn-Ag alloys. The electrical conductivity of the extruded Mg_(2+x)Sn-.3wt%Ag {x =1} alloy was found to be more than its as cast counterpart while the Seebeck coefficient values remained almost the same.

• Journal of Electrochemical Science and Technology
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• 제11권3호
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• pp.310-317
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• 2020

A development of disposable strip-type galactose sensor for point-of-care testing (POCT) was studied, which was constructed using screen-printed carbon electrodes. Galactose levels were determined by the redox reaction of galactose oxidase in the presence of potassium ferricyanide as an electron transfer mediator in a small sample volume (i.e., less than 1 µL). The optimal performance of biosensor was systematically designated by varying applied potential, operating pH, mediator concentration, and amount of enzyme on the electrode. The sensor system was identified as a highly active for the galactose measurement in terms of the sensitivity (slope = 4.76 ± 0.05 nA/µM) with high sensor-to-sensor reproducibility, the linearity (R² = 0.9915 in galactose concentration range from 0 to 400 µM), and response time (t_95% = <17 s). A lower applied potential (i.e., 0.25 V vs. Ag/AgCl) allowed to minimize interference from readily oxidizable metabolites such as ascorbic acid, acetaminophen, uric acid, and acetoacetic acid. The proposed galactose sensor represents a promising system with advantage for use in POCT.

• 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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• 제37권11호
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• pp.961-966
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• 1993

옛 동전(銅錢)에 존재하는 이리듐, 금과 은 등 귀금속 원소들을 정량하기 위한 연구를 수행하였다. $^{192}Ir,\;^{198}Au$ 및 $^{110m}Ag$의 방사능 세기를 계측할 때, 반감기가 긴 핵종에서 방출된 큰 감마선 에너지에 의한 간섭을 감소시키기 위하여 용매추출, 이온교환 크로마토그래피 등 방사화학 분리를 적용하였다. 그 결과 이리듐을 $10^{-11}$ g/g양까지 정량할 수 있었고, 또한 Currie의 방법으로 계산한 3종류의 검출한계, 즉 임계, 검출, 정량한계를 향상시킬 수 있었다. 이리듐의 회수율을 결정하기 위하여 담체를 첨가하여 방사화학 분리를 한 후 중성자를 제조사하였다. 5개의 동전 중의 Ir, Au 및 Ag에 대한 평균 회수율은 각각 65.3%, 98.5%, 99.5%이었다.

• Nuclear Engineering and Technology
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• 제45권1호
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• pp.61-66
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• 2013

Among the radioactive wastes generated from the nuclear power plant, a radioactive nuclide such as $^{129}I$ is classified as a difficult-to-measure (DTM) nuclide, owing to its low specific activity. Therefore, the establishment of an analytical procedure, including a chemical separation for $^{129}I$ as a representative DTM, becomes essential. In this report, the adsorption and recovery rate were measured by adding $^{125}I$ as a radio-isotopic tracer ($t_{1/2}$ = 60.14 d) to the simulation sample, in order to measure the activity concentration of $^{129}I$ in a pressurized-water reactor primary coolant. The optimum condition for the maximum recovery yield of iodine on the anion exchange resins (AG1 x2, 50-100 mesh, $Cl^-$ form) was found to be at pH 7. In this report, the effect of the boron content in a pressurized-water reactor primary coolant on the separation process of $^{129}I$ was examined, as was the effect of $^3H$ on the measurement of the activity of iodine. As a result, no influence of the boron content and of the simultaneous $^3H$ presence was found with activity concentrations of $^3H$ lower than 50 Bq/mL, and with a boron concentration of less than 2,000 ${\mu}g/mL$.