• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.83-89
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• 2020

For the past few decades, as part of efforts to protect the environment where fossil fuels, which have been a key energy resource for mankind, are becoming increasingly depleted and pollution due to industrial development, ecofriendly secondary batteries, hydrogen generating energy devices, energy storage systems, and many other new energy technologies are being developed. Among them, the lithium-ion battery (LIB) is considered to be a next-generation energy device suitable for application as a large-capacity battery and capable of industrial application due to its high energy density and long lifespan. However, considering the growing battery market such as eco-friendly electric vehicles and drones, it is expected that a large amount of battery waste will spill out from some point due to the end of life. In order to prepare for this situation, development of a process for recovering lithium and various valuable metals from waste batteries is required, and at the same time, a plan to recycle them is socially required. In this study, we introduce a nanoscale pattern transfer printing (NTP) process of Li2CO3, a representative anode material for lithium ion batteries, one of the strategic materials for recycling waste batteries. First, Li2CO3 powder was formed by pressing in a vacuum, and a 3-inch sputter target for very pure Li2CO3 thin film deposition was successfully produced through high-temperature sintering. The target was mounted on a sputtering device, and a well-ordered Li2CO3 line pattern with a width of 250 nm was successfully obtained on the Si substrate using the NTP process. In addition, based on the nTP method, the periodic Li2CO3 line patterns were formed on the surfaces of metal, glass, flexible polymer substrates, and even curved goggles. These results are expected to be applied to the thin films of various functional materials used in battery devices in the future, and is also expected to be particularly helpful in improving the performance of lithium-ion battery devices on various substrates.

• Journal of the Korean Magnetics Society
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• v.13 no.1
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• pp.15-20
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• 2003

Diffusion speed of Cu metal fine particle is fast better than CuO, so it will promote grain growth in sintering. In this paper, the influence on substituting Cu fine particle for CuO of NiCuZn ferrite with basic composition (N $i_{0.204}$C $u_{0.204}$Z $n_{0.612}$ $O_{1.02}$)F $e_{1.98}$ $O_{2.98}$ has been investigated with varying Cu/CuO ratio. The perfect spinel structure of sintered specimen at 90$0^{\circ}C$ was confirmed by the analysis of XRD patterns. The best condition was obtained when the ratio of Cu/CuO was 60%, and the permeability was 1100 and Ms was 87 emu/g in this condition. Cu has influenced on grain growth in sintering, substituting Cu fine particle for CuO could lower sintering temperature over the 3$0^{\circ}C$. After sintering, substituting Cu performed as good as CuO.s CuO.s CuO.

• Journal of the Korean Electrochemical Society
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• v.11 no.2
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• pp.100-104
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• 2008

Titanium sheet metal substrates used in thin film batteries were wet etched and their surface area was increased in order to increase the discharge capacity and power density of the batteries. To obtain a homogeneous etching pattern, we used a conventional photolithographic process. Homogeneous hemisphere-shaped wells with a diameter of approximately $40\;{\mu}m$ were formed on the surface of the Ti substrate using a photo-etching process with a $20\;{\mu}m{\times}20\;{\mu}m$ square patterned photo mask. All-solid-state thin film cells composed of a Li/Lithium phosphorous oxynitride (Lipon)/$LiCoO_2$ system were fabricated onto the wet etched substrate using a physical vapor deposition method and their performances were compared with those of the cells on a bare substrate. It was found that the discharge capacity of the cells fabricated on wet etched Ti substrate increased by ca. 25% compared to that of the cell fabricated on bare one. High discharge rate was also able to be obtained through the reduction in the internal resistance. However, the cells fabricated on the wet etched substrate exhibited a higher degradation rate with charge-discharge cycling due to the nonuniform step coverage of the thin films, while the cells on the bare substrate demonstrated a good cycling performance.

• Journal of Welding and Joining
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• v.32 no.4
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• pp.46-54
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• 2014

In this study, the effect of bonding temperature and bonding pressure on deformation and tensile properties of diffusion bonded joint of STS304 compact heat exchanger was investigated. The diffusion bonds were prepared at 700, 800 and $900^{\circ}C$ for 30, 60 and 90 min in pressure of 3, 5, and 7 MPa under high vacuum condition. The height deformation of joint decreased and the width deformation of joint increased with increasing bonding pressure at $900^{\circ}C$. The ratio of non-bonded layer and void observed in the joint decreased with increasing bonding temperature and bonding pressure. Three types of the fracture surface were observed after tensile test. The non-bonded layer was observed in diffusion bonded joint preformed at $700^{\circ}C$, the non-bonded layer and void were observed at $800^{\circ}C$. On the other hand, the ductile fracture occurred in diffusion bonded joint preformed at $900^{\circ}C$. Tensile load of joint bonded at $800^{\circ}C$ was proportional to length of bonded layer and tensile load of joint bonded at $900^{\circ}C$ was proportional to minimum width of pattern. The tensile strength of joint was same as base metal.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.610-614
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• 2013

Massive intercalation of urea into montmorillonite (MUCH) was recently proposed to enhance urea use efficiency through smart suppression of emission of $NH_3$ and NOx. This study was to synthesize citrate-incorporated MUCH (Cit-MUCH) which can enhance suppression of $NH_3$ volatilization. The XRD pattern of Cit-MUCH was very similar to that of MUCH to indicate successful incorporation of citric acid into MUCH. Incorporation of citric acid was confirmed by the existence of $COO^-$ symmetric stretching vibration. During the initial 4 days after application, $NH_3$ volatilization from both bare and perilla-planted soils was much more suppressed by application of Cit-MUCH than MUCH. A peak volatilization rate decreased from 28.3 N mg $m^{-2}\;h^{-1}$ of MUCH-broadcasted soil to 22.2 N mg $m^{-2}\;h^{-1}$ of Cit-MUCH-broadcast soil. $NH_3$ volatilization was less in planted soil than bare soil for 72 hrs after application. These results showed that incorporation of citric acid led to increase in suppression of ammonia volatilization from urea-applied soils.

• Journal of the Korean Chemical Society
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• v.29 no.5
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• pp.516-521
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• 1985

Ethylenediamine-triacetatocobalt (III) complexes with an ammine, an ethylene-diamine, and a trimethylenediamine as the unidentate ligand were prepared, and were isolated as only one isomer for each case by the Dowex 50W-X8, cation exchange resin in $H^+$ form. The geometrical isomer of these complexes have been assigned cis-equatorial form in the three possible geometrical isomers from the elemental analysis, pH titration, IR, NMR, and electronic absorption spectrum. It was found that $[CoN_3O_3]$ system of the meridional form with multidentate ligand have the first absorption band of the largely splitting pattern, and that the diamines (ethylenediamine, trimethylenediamine) have coordinated to the central cobalt (III) ion as a unidentate ligand.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.430.2-430.2
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• 2016

The front transparent conductive oxide (TCO) films in thin fill solar cell should exhibit high transparency, conductivity, good surface morphology and excellent light scattering properties. The light trapping phenomenon is limited due to random surface structure of TCO films. The proper control of surface structure and uniform cauliflower TCO films may be appropriate for efficient light trapping. We report light trapping scheme of ICP-RIE glass texturing by SF6/Ar plasma for high roughness and haze ratio of ITO films. It was observed that the variation of etching time, pattern size and Ar flow ratio during ICP-RIE process were important factors to improve the diffused transmittance and haze ratio of textured glass. The ICP-RIE textured glass showed low etching rates due to the presence of metal elements like Al, B, F and Na. The ITO films deposited on textured glass substrates showed the high RMS roughness and haze ratio in the visible wavelength region. The change in surface morphology showed negligible influence on electrical and structural properties of ITO films. The ITO films with high roughness and haze ratio can be used to improve the performance of thin film solar cells.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.4
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• pp.533-548
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• 1998

The purpose of this study was to investigate the influence of balancing interference on the mandibular movement and masticatory muscle activity. 5 subjects(male. average age of 24.3) without dysfuction in masticatory system were selected. The balancing interference was provided by construction of cast metal crown and onlay on the upper and lower first molars. Clinical examination, changes displacement and velocity, and muscle activity were recorded and analyzed by means of BioPak system(Bioresearch Inc., Milwaukee Wisconsin. USA). The results were as follows ; 1. In clinical examination, various symptoms were reported by all subjects after application of interference. Almost symptoms were subsided after elimination of interference. 2. In the border movements in frontal plane, lateral border movement toward non-interference side was changed according to the interference after application of interference. Immediately after removal of interference, border movements' pattern was recovered as same as before experiment. 3. During gum chewing on the non-interference side, horizontal movement was decreased immediately after application of interference(p<0.05). 1 week after application of interference, horizontal movement was more decreased in 3 subjects and showed a chopping type masticatory stroke. But in 2subjects, horizontal movement was increased to avoid interference. 4. In EMG of the mandibular rest position, no significant changes were showed in the experiment period(p>0.05). 5. During gum chewing on the interference side, the activity of opposite temporal muscle was increased immediately after application of interference(p<0.05). 1 week after application of interference. The activity of ipsilateral temporal muscle and left and right masseter muscles was increased (p<0.05). 1 week after elimination of interference, increased muscle activity was recovered about the same level as before experiment. 6. During gum chewing on the non-interference side, 1 week after application of interference, the activity of ipsilateral temporal muscle was increased (p<0.05). 1 week after elimination of interference. increased muscle activity was returned about the same level as before experiment.

• Korean Journal of Materials Research
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• v.19 no.2
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• pp.108-110
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• 2009

Transparent Sn-doped $In_2O_3$ (ITO) single-layer and ITO/Au/ITO multilayer films were deposited on glass substrates by reactive magnetron sputtering to compare the properties of the films. They were then annealed in a vacuum of $1{\times}10^{-2}\;Pa$ at temperatures ranging from 150 to $450^{\circ}C$ for 20 min to determine the effect of the annealing temperature on the properties of the films. As-deposited 100 nm thick ITO films exhibit a sheet resistance of $130{\Omega}/{\square}$ and optical transmittance of 77% at a wavelength length of 550 nm. By inserting a 5 nm-thick Au layer in ITO/metal/ITO (IMI) films, the sheet resistance was decreased to as low as $20{\Omega}/{\square}$ and the optical transmittance was decreased to as little as 73% at 550 nm. Post-deposition annealing of ITO/Au/ITO films led to considerably lower electrical resistivity and higher optical transparency. In the Xray diffraction pattern, as-deposited ITO films did not show any diffraction peak, whereas as-deposited ITO/ Au/ITO films have Au (222) and $In_2O_3$ (110) crystal planes. When the annealing temperature reached the 150 - $450^{\circ}C$ range, the both diffraction peak intensities increased significantly. A sheet resistance of $8{\Omega}/{\square}$ and an optical transmittance of 82% were obtained from the ITO/Au/ITO films annealed at $450^{\circ}C$.

• Food Science and Preservation
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• v.12 no.6
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• pp.613-616
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• 2005

The aging degree of Kimchi fermented at $4^{\circ}C$ for 29 days was evaluated by the correlation between the flavor and the acidity analysis. The Kimchi fermentation induced a gradual reduction in pH and an increase in acidity from $0.26\%$ (initial) to $1.15\%$ (29th day). Flavor pattern of the fermented Kimchi was obtained by the electronic nose system with 12 metal oxide sensors. Electronic nose analysis could differentiate the flavor profiles of Kimchi according to the fermentation periods, making 5 group in the principal component analysis (PCA) plot Therefore, aging degree of Kimchi could be differentiated by flavor patterns analysed by electronic nose.