• Transactions on Electrical and Electronic Materials
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• v.10 no.3
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• pp.71-74
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• 2009

Electroplated Cu is a cost efficient metallization method in microelectronic packaging applications. Typically in 3-D chip staking technology, utilizing through silicon via (TSV), electroplated Cu metallization is inevitable for the throughput as well as reducing the cost of ownership (COO).To achieve a comparable film quality to sputtering or CVD, a pre-cleaning process as well as plating process is crucial. In this research, atmospheric plasma is employed to reduce the usage of chemicals, such as trichloroethylene (TCE) and sodium hydroxide (NaHO), by substituting the chemical assisted organic cleaning process with plasma surface treatment for Cu electroplating. By employing atmospheric plasma treatment, marginally acceptable electroplating and cleaning results are achieved without the use of hazardous chemicals. The experimental results show that the substitution of the chemical process with plasma treatment is plausible from an environmentally friendly aspect. In addition, plasma treatment on immersion Sn/Cu was also performed to find out the solderability of plasma treated Sn/Cu for practical industrial applications.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.3
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• pp.179-183
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• 2004

A biocompatible polyelectrolyte complex multilayer (PECML) film consisting of poly-L-lysine (PLL) as a polycation and hyaluronic acid (HA) as a polyanion was developed to test its use for surface modification to prevent cell attachment and protein drug delivery. The formation of PECML through the electrostatic interaction of HA and PLL was confirmed by contact angle measurement, ESCA analysis, and HA content analysis. HA content increased rapidly up to 8 cycles for HA/PLL deposition and then slightly increased with an increasing number of deposition cycle. In vitro release of PLL in the PECML continued up to 4 days and ca. 25% of HA remained on the chitosan-coated cover glass after in vitro release test for 7 days. From the results, PECML of HA and PLL appeared to be stable for about 4 days. The surface modification of the chitosan-coated cover glass with PECML resulted in drastically reduced peripheral blood mononuclear cell (PBMC) attachment. Concerned with its use for protein drug delivery, we confirmed that bovine serum albumin (BSA) as a model protein could be incorporated into the PECML and its release might be triggered by the degradation of HA with hyaluronidase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.498-499
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• 2007

In this paper, we report on a study of the electrode/electrolyte interfaces of MCMB/$LiCoO_2$ cell using Ion-chromatography. The cells for the experiments were preconditioned by cycling three times and stabilized at OCV of 3.0V 4.35V and 4.5V. The stabilized cathode electrode was used for surface characterization investigations. Concerning the $LiCoO_2$/electrolyte interfaces, the result obtained have shown the presence of $F^-\;and\;CO_3^{2-}$ on the surface of cathode electrode as well as increasing the concentration of ions as cell voltage increase.

• Journal of Sensor Science and Technology
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• v.32 no.3
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• pp.147-153
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• 2023

Metal-organic frameworks (MOFs) of cobalt gallate were synthesized and deposited on gold electrodes using self-assembly monolayers (SAMs) and hydrothermal processing. These MOF films exhibit strong adsorption capabilities for gaseous particulates, and the use of SAMs allows the synthesis and deposition processes to be completed in a single step. When cobalt gallate is mixed with SAMs, a coordination bond is formed between the cobalt ion and the carboxylate or hydroxyl groups of the SAMs, particularly under hydrothermal conditions. Additionally, the quartz crystal microbalance (QCM) gas sensor accurately measures the number of particulates adsorbed on the MOF films in real-time. Thus, the QCM gas sensor is a valuable tool for quantitatively measuring gases, such as SO₂, NO₂, and CO₂. Furthermore, the QCM MOF film gas sensor was more effective for gas adsorption than the MOF particles alone and allowed the accurate modeling of gas adsorption. Moreover, the QCM MOF films accurately detect the adsorption-desorption mechanisms of SO₂ and NO₂, which exist as gaseous particulate matter, at specific gas concentrations.

• Applied Chemistry for Engineering
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• v.17 no.2
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• pp.183-187
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• 2006

The choice of solvents for electrolytes solutions is very important to improve the characteristics of charge/discharge in the Li-ion battery system. Such solvent systems have been widely investigated as electrolytes for Li-ion batteries. In this paper, the electrochemical properties of the solid electrolyte interphase film formed on carbon anode surface and the solvent decomposition voltage in 1 M LiPF6/EC:MA(x:y) electrolyte solutions prepared from the various mixing volume ratios are investigated by chronopotentiometry, cyclic voltammetry, and impedance spectroscopy. As a result, the solvent decomposition voltages are varied with the ionic conductivity of the electrolyte. Electrochemical properties of the passivation film were different, which are dependent on the mixture ratio of the solvents. Therefore, the most appropriate mixing ratio of EC and MA as a solvent in 1 M $LiPF_6/(EC+MA)$ system for Li-ion battery is approximately 1:3 (EC:MA, volume ratio).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1313-1318
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• 2006

The mechanism fur the surface film formation was studied by in situ Atomic Force Microscopy (AFM) observation of a highly oriented pyrolytic graphite (HOPG) basal plane surface during cyclic voltammetry at a slow scan-rate of 0.5 mV $s^{-1}$ in 1 moi $dm^{-3}$ (M) $LiPF_6$ dissolved in a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC). Decomposition of the electrolyte solution began at a potential around 2.15 V vs. $Li^+$/Li on step edges. In the potential range 0.95-0.8 V vs. $Li^+$/Li, flat areas (hill-like structures) and large swelling appeared on the surface. It is considered that these two features were formed by the intercalation of solvated lithium ions and their decomposition beneath the surface, respectively. At potentials more negative than 0.80 V vs. $Li^+$/Li, particle-like precipitates appeared on the basal plane surface. After the first cycle, the thickness of the precipitate layer was 30 nm. The precipitates were considered to be decomposition of the lithium salt ($LiPF_6$) and solvent molecules (EC and DEC), and to have an important role in suppressing further solvent decomposition on the basal plane.

• Journal of the Korean Electrochemical Society
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• v.26 no.1
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• pp.11-18
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• 2023

As the use of lithium-ion secondary batteries is rapidly increasing due to the rapid growth of the electric vehicle market, the disposal and recycling of spent batteries after use has been raised as a serious problem. Since stored energy must be removed in order to recycle the spent batteries, an effective discharging process is required. In this study, graphite and NCM622 were used as active materials to manufacture coin-type half cells and full cells, and the electrochemical behavior occurring during overdischarge was analyzed. When the positive and negative electrodes are overdischarged respectively using a half-cell, a conversion reaction in which transition metal oxide is reduced to metal occurs first in the positive electrode, and a side reaction in which Cu, the current collector, is corroded following decomposition of the SEI film occurs in the negative electrode. In addition, a side reaction during overdischarge is difficult to occur because a large polarization at the initial stage is required. When the full cell is overdischarged, the cell reaches 0 V and the overdischarge ends with almost no side reaction due to this large polarization. However, if the full cell whose capacity is degraded due to the cycle is overdischarged, corrosion of the Cu current collector occurs in the negative electrode. Therefore, cycled cell requires an appropriate treatment process because its electrochemical behavior during overdischarge is different from that of a fresh cell.

• Korean Journal of Materials Research
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• v.22 no.2
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• pp.86-90
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• 2012

Insoluble catalytic electrodes were fabricated by RF magnetron sputtering of Pt on Ti substrates and the performance of seawater electrolysis was compared in these electrodes to that is DSA electrodes. The Pt-sputtered insoluble catalytic electrodes were nearly 150 nm-thick with a roughness of $0.18{\mu}m$, which is 1/660 and 1/12 of these values for the DSA (dimensionally stable anodes) electrodes. The seawater electrolysis performance levels were determined through measurements of the NaOCl concentration, which was the main reaction product after electrolysis using artificial seawater. The NaOCl concentration after 2 h of electrolysis with artificial seawater, which has 3.5% NaCl normally, at current densities of 50, 80 and 140 mA/$cm^2$ were 0.76%, 1.06%, and 2.03%, respectively. A higher current density applied through the electrodes led to higher electrolysis efficiency. The efficiency reached nearly 58% in the Pt-sputtered samples after 2 h of electrolysis. The reaction efficiency of DSA showed higher values than that of the Pt-sputtered insoluble catalytic electrodes. One plausible reason for this is the higher specific surface area of the DSA electrodes; the surface cracks of the DSAs resulted in a higher specific surface area and higher reaction sites. Upon the electrolysis process, some Mg- and Ca-hydroxides, which were minor components in the artificial seawater, were deposited onto the surface of the electrodes, resulting in an increase in the electrical resistances of the electrodes. However, the extent of the increase ranged from 4% to 7% within an electrolysis time of 720 h.

• Journal of Chest Surgery
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• v.11 no.2
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• pp.129-134
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• 1978

Two hundred and seventeen patients underwent diagnostic rigid bronchoscopy or bionchofiberscopy to evaluate the cytologic diagnosis in the lung cancer patient at the department of chest surgery of Yon-Sei university, college of the medicine from 1971 to 1977 year. One hundred and twenty cases of these patients were taken rigid bronchoscopy and ninety four cases of these patient were taken bronchofiberscopy. Cytologic examination of the sputum was done in 214 cases and sputum cytology was positive in 50 cases [23.4%]. Rigid bronchoscopy was made in 120 cases and this bronchoscopic cytology including bronchial washing and bronchial biopsy was positive in 34 cases [28.5%]. Bronchofiberscopy was performed in 94 cases and was positive in 45 cases [47.5%]. Histopathologically, 41 cases [43.6%] were epidermoid cell carcinoma, 8 cases [8.5%]of undifferentiated cell type, 12 cases [12.8%]of adenocarcinoma, 8 cases [8.5%]of alveolar cell type, and the 25 cases were undetermined. Cytologic examination of the sputum lacks the accuracy of the bronchoscopies in terms of both localization and accurate histologic indentification of the type of neoplasm. Rigid bronchoscope has the advantage of permitting identification of a tumor in a central location and of providing a sufficient amount of biopsy material for accurate diagnosis of carcinoma. However, it has the disadvantage of limiting examination to the larger, more central portions of the tracheobronchial tree. Bronchofiberscope had the advantage of examine upper lobe as well as other portions of the tracheobronchial tree which could not be visualized with the rigid bronchoscopy. A positive diagnosis in bronchofiberscopy was obtained in the highest rate, 47. 8% [45 cases]. A1 last, if a bronchogenic carcinoma is suspected on the basis of either symptoms of an abnormality on the chest film the diagnostic work-up-sputum cytology, bronchial washing, bronchoscopic biopsy, scalene node biopsy, thoracentesis and mediastinoscopy explothoracotomy etc-should precede in an attempt not only to obtain the higher positive diagnosis but also to obtain a tissue diagnosis and to evaluate the stage of the disease and to ascertain the appropriate mode of therapy.

• Journal of Yeungnam Medical Science
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• v.17 no.2
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• pp.123-128
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• 2000

Purpose: This study was aimed to develop a new vaginal applicator(Shin's Applicator) for 2-channel high-dose rate vaginal brachytherapy to evaluate uniformity of surface dose, and to present 3-dimensional dose distribution of the applicator. Methods: Shin's Applicator was inexpensively constructed using human soft tissue equivalent acrylic bar. We evaluated dose uniformity along the applicator surface using film densitometer and performed vaginal intracavitary brachytherapy after insertion of the applicator using HDR brachytherapy planning software and brachytherapy unit(Ralstron-20B). Results: Shin's Applicator allows improved dose distribution than the existing 1-channel cylinder and achieves diminished urinary bladder and rectal dose by 20%. Conclusions: From the above results, it can be concluded that Shin's Applicator may be an improved form of a vaginal applicator. Furthermore, it can be suggested that this applicator has an advantage, for it prevents vaginal stenosis after radiation therapy and can be used as a disposable vaginal dilator. Further follow up examination with radiological study may be helpful to evaluate the therapeutic efficacy of this applicator.