• 한국표면공학회지
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• 제32권6호
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• pp.686-694
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• 1999

Insoluble anodes of the Ta/Ir mixed metal oxide for electrodeposition of Ni-W alloy in ammoniacal citrate bath were prepared by thermal decomposition method. Ti plate was etched in boiling oxalic acid solution and coated with ethanol solution of $TaCl_{5}$ and $IrCl_4$ mixed in a fixed ratio, followed by drying and treating at various temperatures. The coating layer of these insoluble anode was characterized by SEM, EDX, XRD and DSC. The decomposition rate of citric acid in plating bath was determined by measuring the $CO_2$ gas evolved at the anodes with Gas Chromatography. Evolution of $CO_2$ gas from Ta/Ir oxide anodes decreased about 5% compared with that of Pt. The $CO_2$ gas evolution was increased with the amount of Ir-oxide in the coatings. The coatings which have more than 40% ratio of Ta content and heat-treated at the temperature higher than $400^{\circ}C$ showed better efficiency

• 한국표면공학회지
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• 제37권6호
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• pp.335-343
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• 2004

Bath stabilizers in the electroless nickel(EN) plating solution are known to prevent sudden bath decomposition and extend its lifetime. Further, every stabilizer has a different role and function in EN solution and it influences the surface structure. In this study, the effects of various stabilizers on the deposition rate, surface morphology, deposition content of phosphor and hardness were investigated.

• 한국표면공학회지
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• 제46권4호
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• pp.153-157
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• 2013

The defect like the void or seam is frequently generated in the PCB (Printed Circuit Board) Via-Filling plating inside via hole. The organic additives including the accelerating agent, inhibitor, leveler, and etc. are needed for the copper Via-Filling plating without this defect for the plating bath. However, the decomposition of the organic additive reduces the lifetime of the plating bath during the plating process, or it becomes the factor reducing the reliability of the Via-Filling. In this paper, the interaction of each organic additives and the decomposition of additive were discussed. As to the accelerating agent, the bis (3-sulfopropyl) disulfide (SPS) and leveler the Janus Green B (JGB) and inhibitor used the polyethlylene glycol 8000 (PEG). The research on the interaction of the organic additives and decomposition implemented in the galvanostat method. The additive decomposition time was confirmed in the plating process from 0 Ah/l (AmpereHour/ liter) to 100 Ah/l with the potential change.

• 자원리싸이클링
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• 제20권6호
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• pp.50-55
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• 2011

태양전지(Photovoltaic, PV) 모듈의 층간 접착제로 사용된 EVA(Ethylene Vinyl Acetate)를 초음파 조사(irradiation)를 이용하여, 선택적으로 분해함으로써 모듈 내 실리콘웨이퍼(Si-wafer)로 제조된 셀(cell)을 분리, 회수하는 연구를 진행하였다. 본 실험에 사용한 초음파 발생장치는 bath-type의 초음파 세척기 (Output: 130 W, Frequency: 40 kHz)로, PV모듈과의 거리는 2 cm로 고정하고 유기용매 종류, 농도, 온도를 조절하면서 EVA 분해 및 셀의 분리 최적 조건을 도출하였다. $55^{\circ}C$, 5M인 조건에서는 용매 종류에 상관없이 160 min 이내에 EVA층의 완전 분해는 가능하였으나, 분해과정 중 발현되는 팽창현상(swelling)에 의해 셀의 일부분이 파손된 상태로 회수되었다. 반면에 $65^{\circ}C$, 5M조건에서는 셀의 파손이 억제된 상태로 회수 가능하였으며, 이는 온도 상승에 의해 EVA 성분의 분해속도가 상승되고, 이로 인해 EVA층의 팽창현상이 발현되기 전에 분해가 일어난 결과라고 판단된다.

• Bulletin of the Korean Chemical Society
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• 제27권10호
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• pp.1572-1576
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• 2006

A dimeric precursor, $[Cu(dmae)(OCOCH_3)(H_2O)]_2$ for the CVD of copper metal films, (dmaeH = N,N-dimethylaminoethanol) was synthesized by the reaction of copper(II) acetate monohydrate ($Cu(OCOCH_3)_2{\cdot}H_2O$) and dmaeH in toluene. The product was characterized by m.p. determination, elemental analysis and X-ray crystallography. Molecular structure of $[Cu(dmae)(OCOCH_3)(H_2O)]_2$ shows that a dimeric unit $[Cu(dmae)(OCOCH_3)(H_2O)]_2$ is linked to another through hydrogen bond and it undergoes facile decomposition at 300 C to deposit granular copper metal film under nitrogen atmosphere. The decomposition temperature, thermal behaviour, kinetic parameters, evolved gas pattern of the complex, morphology, and the composition of the film were also investigated.

• Bulletin of the Korean Chemical Society
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• 제4권5호
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• pp.203-208
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• 1983

A thermal decomposition of trichloroethylene was studied in the temperature range of 440-$460^{\circ}C$ by using the conventional static system. In order to investigate the pressure dependence of reaction and to eliminate free radical process, propylene was used as the bath gas. The pressure range investigated was 10∼900 Torr. The decomposition was the unimolecular dehydrochlorination and the reaction products were hydrogen chloride and dichloroacetylene. Results were interpreted in terms of the Ric-Ramsperger-Kassel-Marcus (RRKM) unimolecular rate theory and the Arrhenius parameters were determined from fall-off behaviors. The Arrhenius parameters are found to be log $A=13.8{\pm}0.2sec^{-1}$ and E = $56.6{\pm}0.7$ kcal/mole, respectively.

• 한국염색가공학회지
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• 제23권1호
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• pp.51-59
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• 2011

Calcium alginate fiber were prepared by wet spinning of various conditions, including different concentrations of sodium alginate solution and $CaCl_2$ concentrations for coagulating the fiber through an absorption of calcium ion. The absorption of calcium ion during the coagulating step lead to solidify the fibers by the replacement of sodium ion with calcium ion to produce some crosslinking. The concentration of calcium ion in the calcium alginate fiber seems to be well related to the mechanical and physical property of the fiber, such as fiber strength moisture regain, and degree of swelling. The tensile strength of calcium alginate fiber was increased along with the increasing amount of sodium alginate solution. According to EDS analysis, 7 wt% $CaCl_2$ coagulation bath resulted in more calcium ion in the fiber compared to 3 wt% $CaCl_2$ coagulation bath. The decomposition temperature of calcium alginate fiber was $199^{\circ}C$, which $14^{\circ}C$ higher than that of sodium alginate.

• 열처리공학회지
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• 제13권2호
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• pp.71-84
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• 2000

A study on adhesion and wear resistance of VC(vanadium carbide) coating on die steels, STD11 and STD61, has been carried out. The VC coating on the die steels was made by immersing them in molten borax bath, a kind of TRD(thermo-reactive deposition and diffusion). Adhesion strength and wear resistance were investigated using scratch test, indentation test and plate-disc test(Ogoshi type) respectively. The influence of sliding distance on the amount of wear has been determined and dominant wear mechanisms has been characterized using optical microscopy, scanning electron microscopy and EDS spectroscopy. The critical adhesion strength($L_c$) between VC coating layer and substrate(STD11) was increased to 60N($L_c$) in the scratch test. In the case of STD61, the strength increased to 24N. The wear resistance of VC coated die steels was excellent because the diffusion layer formed just below the coating layer. The dominant wear mechanism was identified as adhesive wear for VC coating die steels which were worn by combination of cracking and plucking of VC fragments and disc.

• KIEE International Transactions on Power Engineering
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• 제4A권1호
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• pp.33-41
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• 2004

Knowledge of partial discharge (PD) is important to accurately diagnose and predict the condition of insulation. The PD phenomenon is highly complex and seems to be random in its occurrence. This paper indicates the possible use of chaos theory for the recognition and distinction concerning PD signals. Chaos refers to a state where the predictive abilities of a systems future are lost and the system is rendered aperiodic. The analysis of PD using deterministic chaos comprises of the study of the basic system dynamics of the PD phenomenon. This involves the construction of the PD attractor in state space. The simulation results show that the variance of an orthogonal axis in an attractor of chaos theory increases according to the magnitude and the number of PDs. However, it is difficult to clearly identify the characteristics of the PDs. Thus, we calculated the magnitude on an orthogonal axis in an attractor using singular value decomposition (SVD) and principal component analysis (PCA) to extract the numerical characteristics. In this paper, we proposed the condition monitoring method for gas insulated switchgear (GIS) using SVD for efficient calculation of the variance. Thousands of simulations have proven the accuracy and effectiveness of the proposed algorithm.

• 대한화학회지
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• 제10권1호
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• pp.32-42
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• 1966

$CaCl_2$, CaO 및 $WO_3$로 構成되는 熔融鹽을 黑鉛 陽極과 鐵 陰極으로 電解하여 순수한 金屬텅스텐을 얻는 方法에 관하여 실험하였다. 電氣分解에 적합한 熔融浴을 選定하기 위하여 $CaCl_2$-CaO系와 $CaCl_2-CaWO_4$系에 관한 二相 狀態圖를 작성하였으며 同時에 $CaCl_2$와 $WO_3$와의 高溫下에서의 化學反應을 검토하여 安定한 電解浴을 얻기 위해서는 一定量의 CaO가 添加되어야 할 것임을 알 수 있었다. 炭素陽極을 사용하여 $WO_3$를 W와 CO로 분해시킬 때의 分解電壓은 -0.1 volt이었으며 熱力學的 計算에 의한 것은 -0.3 volt이었다. 熔融鹽을 電氣分解한 結果 金屬텅스텐이 100%에 가까운 電流效率로 電極에 析出되나 이는 陽極에서 二次的으로 발생하는 CO가스에 의하여 쉽게 WC등으로 변화하므로 순수한 텅스텐을 얻기 위해서는 電解浴의 溫度를 $1100^{\circ}C$이상으로 유지하여야 된다는 것을 알게 되었다. 電解浴의 組成은 可及的 低融點과 $WO_3$의 分解, $CaCl_2$의 蒸發 등을 억제하기 위해서는 $CaCl_2$ 100分에 대하여 CaO와 $WO_3$가 각 10 乃至 20分이 適切하였으며 CaO와 $WO_3$의 몰比率은 1이상이 요구되었다. 陰極 電流密度를 1~5 $amp/cm^2$의 範圍에서 變化시켜도 電流效率에 큰 影響이 없었다.