• Toxicological Research
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• v.30 no.4
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• pp.311-316
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• 2014

For the detection of trace copper to be used in medical diagnosis, a sensitive handmade carbon nanotube paste electrode (PE) was developed using voltammetry. Analytical optimized conditions were found at 0.05 V anodic peak current. In the same conditions, various common electrodes were compared using stripping voltammetry, and the PE was found to be more sharply sensitive than other common electrodes. At optimum conditions, the working ranges of $3{\sim}19{\mu}gL^{-1}$ were obtained. The relative standard deviation of $70.0{\mu}gL^{-1}$ was determined to be 0.117% (n = 15), and the detection limit (S/N) was found to be $0.6{\mu}gL^{-1}$ ($9.4{\times}10^{-9}M$). The results were applied in detecting copper traces in the kidney and the brain cells of fish.

• Journal of Environmental Science International
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• v.21 no.11
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• pp.1333-1338
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• 2012

In order to measure the minute amount of Cu(II) in our environment, cyclic voltammetry (CV) and square-wave stripping voltammetry (SWSV) were performed for a trace copper assay using bismuth immobilized on a carbon nanotube paste electrode. An analytical working range of 30 to $240{\mu}g/L$ Cu(II) was obtained for CV and SWSV. The SWSV precision obtained was 0.47 % (n = 15) RSD in $30.0{\mu}g/L$ Cu(II). The detection limit obtained was 3.1 ng/L Cu(II) using SWSV, while the CV yielded the nano-range detection limit through the pre-concentration step. By using this research method, Cu(II) value could be determined in the urine of human sample and in the brain of fish sample. This research can be effectively applied to other cases of measuring minute amount of Cu(II) in living organisms.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.5
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• pp.482-487
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• 2023

A carbon-based hybrid resistor was fabricated using carbon nanotube (CNT) paste as an adhesive layer to establish electrically continuous ohmic contacts between CNT sheets and different CNT sheet or copper based metal alloy plates, and its electrical properties were evaluated. CNT sheets were fabricated using vacuum filtration with a CNT solution dispersed in isopropyl alcohol (IPA) solvent. The electrical characteristics of these carbon-based hybrid resistors were investigated. The CNT paste fulfilled the requirements for forming ohmic contacts between CNT sheets and metal alloy plates, which was attributed to the lowest work function difference and excellent wettability at the interface.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.1
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• pp.69-74
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• 2015

With difficulties during the cleaning of reflow flux residues due to the decrease of the part size and interconnection pitch in the advanced electronic devices, the need for the no-clean solder paste is increasing. In this study, an epoxy curable solder paste was made with SAC305 solder powder and the curable flux of which the main ingredient is epoxy resin and its reflow solderability, flux residue corrosivity and solder joint mechanical properties was investigated with comparison to the commercial rosin type solder paste. The fillet shape of the cured product around the reflowed solder joint revealed that the curing reaction occurred following the fluxing reaction and solder joint formation. The copper plate solderability test result also revealed that the wettability of the epoxy curable solder paste was comparable to those of the commercial rosin type solder pastes. In the highly accelerated temperature and humidity test, the cured product residue of the curable solder paste showed no corrosion of copper plate. From FT-IR analysis, it was considered to be resulted from the formation of tight bond through epoxy curing reaction. Ball shear, ball pull and die shear tests revealed that the adhesive bonding was formed with the solder surface and the increase of die shear strength of about 15~40% was achieved. It was considered that the epoxy curable solder paste could contribute to the improvement of the package reliability as well as the removal of the flux residue cleaning process.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.134-134
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• 2016

The effect of different thermal treatments on the sub-50 nm copper nanoparticles is examined in the aspects of chemical, electrical and surface morphology. The copper nanoparticles are chemically synthesized and fabricated for paste-type solution. Simple bar coating method is practiced as a deposition process to form copper thin film on a typical slide glass. Deposited copper thin films are annealed by two different routes: general tube furnace with 99.99 % Ar atmosphere and selective laser sintering process. The thermal behavior of the different thermal-treated copper thin films is compared by SEM, XRD, FT-IR and XPS analysis. In this study, the laser sintering process ensures low annealing temperature, fast working speed and ambient-accessible route. Moreover, the laser-sintered copper thin film shows good electrical property and enhanced chemical stability than conventional thermal annealing process. Consequently, the proposed laser sintering process can be compatible with plastic substrate for flexible applications.

• Journal of the East Asian Society of Dietary Life
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• v.8 no.4
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• pp.422-429
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• 1998

The content of zinc and copper were analyzed and compared for five favorite traditional Korean dishes. The purpose of the research was to substantiate traditional Korean foods, which are good sources of these two minerals, to emphasize the importance of the minerals and to improve nutritional conditions. Foods were collected from institutional food services and Korean restaurants. The result of the analysis of the minerals are listed below. 1. When the survey was done on the preference and the frequency of intake of 106 Korean traditional dishes, the most popular food item was soybean paste stew (doenjangchigae); the second, barbecued beef (pulgogi): the third, cooked rice with assorted vegetables (pibimpap): the fourth, grilled fishes : the fifth, spicy beef vegetable soup (yukkaejang). The frequency of intake of eating these dishes was also very high. 2. The average one serving portion of each of the five dishes from institutional food services and Korean restaurants are as follows. The average one serving size of cooked rice with assorted vegetables of the two systems were 451.2g and 403.0g; spicy beef vegetable soup, 379.3g and 512.3g; soybean paste stew, 292.0g and 278.8g; barbecued beef, 76.1g and 202.5g: grilled croaker(chogi, fish), 47.5g and 36.5g, and grilled spanish mackerel(samchi, fish), 60.0g and 250.0g. The differences of the average one serving portion between the two systems were very significant. 3. The total average zinc content of each of the five dishes from the two different systems were analyzed. The zinc content of cooked rice ith assorted vegetables from institutional food services was 4.3mg and that from Korean restaurants was 2.9mg; spicy beef vegetable soup, 1. 7mg and 3.2mg: sybean pste stew, 1.4mg and 1.6mg: barbecued beef, 1.9mg and 4.3mg; grilled croaker, 0.5mg and 0.4mg; grilled spanish mackerel, 0.8mg and 2.7mg. The difference between the average of total zinc content of two systems were not statistically significant. 4. The average total copper content of each item from the two different systems were compared. The average total copper content of barbecued beef from institutional food services was 692.4$\mu\textrm{g}$ and that from Korean restaurants was 502.5$\mu\textrm{g}$. The value of the institutional food services system was significantly higher(p＜0.05). Spicy beef vegetable soup, 161.1$\mu\textrm{g}$ and 208.3$\mu\textrm{g}$: soybean paste soup, 290.5$\mu\textrm{g}$ and 308.5$\mu\textrm{g}$; barbecued beef, 217.7$\mu\textrm{g}$ and 339.l$\mu\textrm{g}$: grilled croaker, 51.7$\mu\textrm{g}$ and 44.l$\mu\textrm{g}$; grilled spanish mackerel, 92.0$\mu\textrm{g}$ and 265.2$\mu\textrm{g}$. The difference of the two systems was not significant. 5. The zinc contents per 100g each of five traditional Korean dishes were barbecued beef, 2.2mg, grilled spanish mackerel, 1.2mg, grilled croaker, 1.1mg, cooked rice with assorted vegetables, 0.8mg, soybean paste stew, 0.6mg, spicy beef vegetable soup, 0.5mg. The copper contents were; barbecued beef, 203.0$\mu\textrm{g}$, cooked rice with assorted vegetables, 138.7$\mu\textrm{g}$, grilled spanish mackerel, 137.9$\mu\textrm{g}$, grilled croaker, 119.l$\mu\textrm{g}$, soybean paste stew, 105.l$\mu\textrm{g}$, spicy beef vegetable soup, 40.5$\mu\textrm{g}$.

• Journal of Welding and Joining
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• v.31 no.6
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• pp.65-70
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• 2013

In joining Alumina to copper plate by Mo-Mn metallizing process, the effects of the composition of metallizing paste on the bonding strength were investigated. The bonding strength increased with increasing Mn amount in the paste up to 20% but followed by the decrease with addition of Mn. The maximum bonding strength reached 50MPa at 20%Mn when heated to $1550^{\circ}C$ for 60minute. The addition of Si to the metallizing powder increased the bonding strength of the joint by enhancing the mechanical bonding between the Alumina and the metallizing layer due to the decrease of layer viscosity with the addition of $SiO_2$. It is thought that MnO reacted with $Al_2O_3$ to yield $MnAl_2O_4$ spinel, forming a joint.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1989.06a
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• pp.59-61
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• 1989

The cell parameters of the sintered CdS/CdTe solar cells in which te CuCl$_2$was added in the carbon paste after the sintering of the CdS/CdTe composites an were annealed at 35$0^{\circ}C$ for 10 min in nitrogen are investigated. Voc and FF do not change significantly as the CuCl$_2$increasing up to 500 ppm, Jsc increases with futher increase in copper. The hole concentration, determined by C-V measurement, increases to $1.5\times$10$^{16}$ ㎤ as the copper increased to 25 ppm and then stays at about the same value with further increase in copper.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.09a
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• pp.21-30
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• 2002

According the difference of flex substrate, (reel tape), there are three kind assembly types of LCD driver IC is COG, TCP and COF, respectively. The TCP is the maturest in these types for stability of raw material supply and other specification. And TCP is the major assembly type of LCD driver IC and the huge demand from Taiwan's large TFT LCD panel house since this spring. But due to its package structure and the raw material applied in this package, there is some limitation in fine pitch application of this package type, (TCP). So, COF will be very potential in compact and portable application comparison with TCP in the future. There are three kinds assembly methods in COF, one is ACF by using the anisotropic conductive film to connect the copper lead of tape and gold bump of IC, another is eutectic bonding by using the thermo-pressure to joint the copper lead of tape and gold bump of IC, and last is NCP by using non-conductive paste to adhere the copper lead of tape and gold bump of IC. To have a global realization, this paper will briefly review the status of Taiwan's large TFT panel house, the internal driver IC design house, and the back-end assembly house in the beginning. The different material property of raw material, PI tape is also compared in the paper. The more detail of three kinds of COF assembly method will be described and compared in this paper.

• Korean Journal of Materials Research
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• v.22 no.7
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• pp.335-341
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• 2012

Recently, the demand for the miniaturization of printed circuit boards has been increasing, as electronic devices have been sharply downsized. Conventional multi-layered PCBs are limited in terms their use with higher packaging densities. Therefore, a build-up process has been adopted as a new multi-layered PCB manufacturing process. In this process, via-holes are used to connect each conductive layer. After the connection of the interlayers created by electro copper plating, the via-holes are filled with a conductive paste. In this study, a desmear treatment, electroless plating and electroplating were carried out to investigate the optimum processing conditions for Cu via filling on a PCB. The desmear treatment involved swelling, etching, reduction, and an acid dip. A seed layer was formed on the via surface by electroless Cu plating. For Cu via filling, the electroplating of Cu from an acid sulfate bath containing typical additives such as PEG(polyethylene glycol), chloride ions, bis-(3-sodiumsulfopropyl disulfide) (SPS), and Janus Green B(JGB) was carried out. The desmear treatment clearly removes laser drilling residue and improves the surface roughness, which is necessary to ensure good adhesion of the Cu. A homogeneous and thick Cu seed layer was deposited on the samples after the desmear treatment. The 2,2'-Dipyridyl additive significantly improves the seed layer quality. SPS, PEG, and JGB additives are necessary to ensure defect-free bottom-up super filling.