• Clean Technology
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• v.18 no.2
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• pp.183-190
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• 2012

Electrochemical regeneration of the iron chloride waste solution from PCB etching reduces environmental contamination and produces copper as by-product, so the economic feasibility is high. But iron chloride waste solution contains iron and copper and the reactions occurring in the electrolytic cell are complicated. In this work, the oxidation of iron chloride and copper deposition were examined through batch electrolysis and the optimum conditions of the process parameters were found. The oxidation of ferrous chloride was achieved easily to the desired level. The copper deposition efficiency was high in the reaction using the carbon cathode when the copper density was 12 g/L with the electric current density of $350mA/cm^2$, and the ratio of the $Fe^{2+}$ ion was high. In addition, the possibility of the scale-up was confirmed in continuous operation of bench reactor using the optimum conditions obtained.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.1
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• pp.61-66
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• 2012

Chemical Mechanical Planarization (CMP) is a polishing process used in the microelectronic fabrication industries to achieve a globally planar wafer surface for the manufacturing of integrated circuits. Pad conditioning plays an important role in the CMP process to maintain a material removal rate (MRR) and its uniformity. For metal CMP process, highly acidic slurry containing strong oxidizer is being used. It would affect the conditioner surface which normally made of metal such as Nickel and its alloy. If conditioner surface is corroded, diamonds on the conditioner surface would be fallen out from the surface. Because of this phenomenon, not only life time of conditioners is decreased, but also more scratches are generated. To protect the conditioners from corrosion, thin organic film deposition on the metal surface is suggested without requiring current conditioner manufacturing process. To prepare the anti-corrosion film on metal conditioner surface, vapor SAM (self-assembled monolayer) and FC (Fluorocarbon) -CVD (SRN-504, Sorona, Korea) films were prepared on both nickel and nickel alloy surfaces. Vapor SAM method was used for SAM deposition using both Dodecanethiol (DT) and Perfluoroctyltrichloro silane (FOTS). FC films were prepared in different thickness of 10 nm, 50 nm and 100 nm on conditioner surfaces. Electrochemical analysis such as potentiodynamic polarization and impedance, and contact angle measurements were carried out to evaluate the coating characteristics. Impedance data was analyzed by an electrical equivalent circuit model. The observed contact angle is higher than 90o after thin film deposition, which confirms that the coatings deposited on the surfaces are densely packed. The results of potentiodynamic polarization and the impedance show that modified surfaces have better performance than bare metal surfaces which could be applied to increase the life time and reliability of conditioner during W CMP.

• Journal of the Korean Chemical Society
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• v.33 no.2
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• pp.168-176
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• 1989

Theoretical analysis of HF chemical laser models are performed through chemical reaction kinetics, gain process and stimulated emission process. A chemical laser of F+$H_2$ nonchain reaction is investigated through V-R transitions of excited HF for vibrational levels up to v = 3 and rate equations including nonchain pumping and deactivation. On this analysis, harmonic and anharmonic vibrational levels are considered separately and the results of the corresponding power calculations are showed very small difference between the two. Output powers are calculated with variation of temperature and initial concentrations of $H_2$. A HF chemical laser of $H_2$+$F_2$ chain reaction is also simulated with a premixed initial condition. Results of present model calculations are satisfactory through comparison with detailed calculations reported by others.

• Tuberculosis and Respiratory Diseases
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• v.58 no.2
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• pp.135-141
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• 2005

배경 및 목적 : Multidrug Resistance-1 (MDR1) 유전자는 다약제내성에 관여하는 P-glycoprotein을 암호화한다. MDR1 유전자의 다형성은 P-glycoprotein의 발현과 기능의 차이를 일으켜 항암화학요법 반응에 영향을 미칠 수 있을 것이다. 저자들은 소세포폐암 환자에서 MDR1 유전자의 다형성과 일배체형에 따른 항암화학요법에 대한 반응을 조사하였다. 대상 및 방법 : 경북대학병원에서 병리적으로 소세포폐암으로 진단받고 etoposide-cisplatin 항암화학요법을 받은 54명을 대상으로 하였다. 전혈 5cc에서 DNA를 추출하고 PCR-RFLP법을 통해 MDR1 유전자 엑손 21의 2677G>T 다형성과, 엑손 26의 3435C>T 다형성을 조사하고 다형성과 일배체형에 따른 항암화학요법의 반응을 조사하였다. 결 과 : 2677G>T 유전자형에 따른 항암화학요법의 반응은 유의한 차이가 없었다. 3435 CC 유전자형은 3435 CT+TT 형에 비해 치료 반응율이 유의하게 높았다 (P = 0.025). 유전자형 분석 결과와 일치되게 2677G/3435C 일배체형은 다른 일배체형에 비해 치료반응을 보이는 경우가 유의하게 많았다 (P = 0.015). 결 론 : 소세포폐암에서 MDR1 유전자의 2677G>T와 3435C>T 다형성 및 이들 다형성의 일배체형은 etoposide-cisplatin 항암화학요법의 반응을 예측할 수 있는 지표로 사용될 수 있을 것으로 생각된다.

• Journal of the Mineralogical Society of Korea
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• v.18 no.3 s.45
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• pp.183-194
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• 2005

The mineralogical, physicochemical and thermal properties of the Myogi bentonite occurring in Japan were measured. A adsorption properties of U, Th, Ce and Eu ions on the Myogi bentonite were also investigated in different solution concentrations and pH conditions. The Myogi bentonite showed a strong alkaline character (pH 10.4), very high swelling, viscosity property and CEC, and a slow flocculation behavior due to the strong hydrophilic property. By the thermal analysis, the dehydroxylation of crystal water in bulk and clay fractions of the Myogi bentonite occur at $591^{\circ}C$ and $658^{\circ}C$, respectively, The adsorption experiments of ions such as U, Th, Ce and Eu were conducted for 0.2 g bentonites with 20mL solutions of various concentrations and different pH conditions with pH 3, 5, 7, 9, and 11. As a result, the Myogi bentonite showed excellent adsorption capacities for Ce, Th and Eu ions, whereas U ion showed very low adsorption capacity. Generally, Ce, Th and Eu ions showed the similar adsorption properties for the different concentrated solutions and pH conditions. These adsorption properties seem to be affected by the formation of various forms of chemical species and precipitation as well as ionic exchange reaction and surface adsorptions on smectite. Some associated zeolite minerals perhaps have some effects on the adsorption of U, Th, Ce and Eu on Myogi bentonite.

• Journal of the Korean Chemical Society
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• v.53 no.4
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• pp.422-426
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• 2009

An efficient, chemoselective and practical protocol for N-Boc protection of amines using di-tertbutoxypyrocarbonate $(Boc)_{2}O$ in presence of Indion 190 resin. Resin was easily separated from the reaction mixture by filtration and reused in subsequent reactions without any apparent loss of activity. Simple workup, mild condition, short reaction time and high yield are some of the striking features of the present process.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.3
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• pp.74-81
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• 2013

Due to its accuracy and efficiency, reduced kinetic mechanism of diesel surrogate is widely used as fuel model when applying 3-D diesel engine simulation. But for the well-developed prediction of diesel surrogate reduced kinetic mechanism, it is important to know some meaningful factors which affect to ignition delay time. Meanwhile, ignition delay time consists of two parts. One is the chemical ignition delay time related with the chemical reaction, and the other is the physical ignition delay time which is affected by physical behavior of the fuel droplet. Especially for chemical ignition delay time, chemical properties of each fuel were studied for a long time, but researches on their mixtures have not been done widely. So it is necessary to understand the chemical characteristics of their mixtures for more precise and detailed modeling of surrogate diesel oil. And it shows same ignition trend of paraffin mixture with those of single component, and shorter ignition delay at low/high initial temperature when mixing paraffin and toluene.

• Clean Technology
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• v.18 no.4
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• pp.432-439
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• 2012

The electrocatalytic oxidation of CO was studied using carbon-supported 20 wt% PtRu (PtRu/C) catalysts, which were prepared with different Pt : Ru atomic ratios from 7 : 3 to 3 : 7 using a colloidal method combined with a freeze-drying procedure. The bimetallic PtRu/C catalysts were characterized by various physicochemical analyses, including X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). CO stripping voltammetry measurements indicated that the addition of Ru with a Pt catalyst significantly improved the electrocatalytic activity for CO electrooxidation. Among the tested catalysts, the $Pt_5Ru_5/C$ catalyst had the lowest onset potential (vs.Ag/AgCl) and the largest CO EAS. Structural modification via lattice parameter change and electronic modification in the unfilled d band states for Pt atoms may facilitate the electrooxidation of CO.

• Analytical Science and Technology
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• v.29 no.5
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• pp.225-233
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• 2016

The chemical engrafting of polymers on particle surface, plays an important role on selective partitioning of micro/nano-particles in the separated layers of liquid media, such as aqueous two phase systems (ATPSs). Three polymers, dextran, poly (ethylene glycol) and albumin were chosen and chemically conjugated to the polystyrene (PS) magnetic microparticle surface. The attachment of long-chained polymer chains which may switch the partition behavior, can be simply performed by S_N2 substitution of various polymers having primary amine functional groups, with p-toluenesulfonyl (tosyl)-activated polystyrene magnetic micro-particles. The surface modification of microparticle was probed by infrared microscopy. The distinctive peak represents N-H stretching vibration mode for microparticles after the reaction and it is common for all three polymers examined. The locations of main peaks are similar for all micro-particles but different and distinguishable in fingerprint region.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.518-529
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• 1996

To develope chemical heat pump using available energy sources such as solar heat and many kinds of waste thermal energy we have studied the enhancement effect of inserted fins in cylindical packed bed reactor. Two dimensionnal(radial and circumferential) partial differential eqaetions, concerning heat and masstransfer in CaO packed bad, are solved numerically to describe the characteristics of the reaction of fins inserted reactor and heat transfer. The results obtained by numerical analysis about two dimensional profiles of temperature and conversion in the reactant in the packed bed and exothermic heat amount released from the reactor are follows; -. The insertion of fins in reactor can redue the reaction completion time by half. -. The rate of thermochemical reaction depends of the temperature and concentration and it is also governed by the boundary conditions and heat transfer rate in the particle packed bed.