• Journal of the Korean Electrochemical Society
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• v.6 no.2
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• pp.93-97
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• 2003

The electrode for a supercapacitor was prepared using an amorphous ruthenium oxide, which was synthesized from ruthenium trichloride hydrate$(RuO_2{\cdot}nH_2O)$. A supercapacitor was assembled with an electrode of ruthenium oxide material on a current collector of tantalum, and an electrolyte of 4.8 M sulfuric acid. The result of the AC impedance analyses on $Ta/H_2SO_4(4.8 M)/Pt$ cell showed that tantalum was stable at the potential range of $0.0\~1.1V(vs. SCE)$. Therefore, Ta film could be used the supercapacitor as a current collector. The irreversible hydrolysis in the supercapacitor occurred over ca. 1.0V(vs.SCE) when the supercapacitor was protonated to 0.5V(vs. SCE). The supercapacitor protonated to 0.5V(vs.SCE) showed good electrochemical properties when it was tested at the potential range of 1.0V in the charge-discharge test. The potential range of the electrodes including the positive and the negative electrode was varied between -0.004 and 0.995V(vs. SCE). The potential ranges of the positive and the negative electrode were $-0.004\~0.515V(vs.\;SCE)\;and\; 0.515\~0.995V(vs.\;SCE)$, respectively.

• Journal of Sensor Science and Technology
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• v.11 no.6
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• pp.327-334
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• 2002

Fine particles of $SnO_2$ were fabricated by the sol-gel powder processing using tine(II) chloride dihydrate($SnCl_2{\cdot}2H_2O$) and ethanol($C_2H_5OH$) as raw materials. The powders were investigated about the properties and electrical sensing. Gel powders were fabricated by drying of sol at $120^{\circ}C$ after aging 72hrs and 168hrs. The amount of $SnO_2$ phase was increased below $600^{\circ}C$ due to the elimination of volatile components, and the $SnO_2$ phase was almost completed by the heat treatment at $700^{\circ}C$ for 30min. The grain sizes were about 30nm below $700^{\circ}C$, and it showed the narrow distribution of the grain sizes. The specimens to measure electrical properties were fabricated by the thick film screen printing technique on the alumina substrates. The conductance of $SnO_2$ was showed the intrinsic behaviour of semiconducting ceramics above at $450^{\circ}C$. The constant conductance was observed in the temperature range of $200{\sim}450^{\circ}C$. The sensing properties of response time, recovery, and sensitivity of CO were improved with aging time.

• Korean Journal of Materials Research
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• v.20 no.11
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• pp.586-591
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• 2010

Solar cells have been more intensely studied as part of the effort to find alternatives to fossil fuels as power sources. The progression of the first two generations of solar cells has seen a sacrifice of higher efficiency for more economic use of materials. The use of a single junction makes both these types of cells lose power in two major ways: by the non-absorption of incident light of energy below the band gap; and by the dissipation by heat loss of light energy in excess of the band gap. Therefore, multi junction solar cells have been proposed as a solution to this problem. However, the $1^{st}$ and $2^{nd}$ generation solar cells have efficiency limits because a photon makes just one electron-hole pair. Fabrication of all-silicon tandem cells using an Si quantum dot superlattice structure (QD SLS) is one possible suggestion. In this study, an $SiO_x$ matrix system was investigated and analyzed for potential use as an all-silicon multi-junction solar cell. Si quantum dots with a super lattice structure (Si QD SLS) were prepared by alternating deposition of Si rich oxide (SRO; $SiO_x$ (x = 0.8, 1.12)) and $SiO_2$ layers using RF magnetron co-sputtering and subsequent annealing at temperatures between 800 and $1,100^{\circ}C$ under nitrogen ambient. Annealing temperatures and times affected the formation of Si QDs in the SRO film. Fourier transform infrared spectroscopy (FTIR) spectra and x-ray photoelectron spectroscopy (XPS) revealed that nanocrystalline Si QDs started to precipitate after annealing at $1,100^{\circ}C$ for one hour. Transmission electron microscopy (TEM) images clearly showed SRO/$SiO_2$ SLS and Si QDs formation in each 4, 6, and 8 nm SRO layer after annealing at $1,100^{\circ}C$ for two hours. The systematic investigation of precipitation behavior of Si QDs in $SiO_2$ matrices is presented.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.99-106
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• 1982

Vacuum-packed and seasoned-dried products of filefish, Navodon modestus, caught in large quantities in the coasts of Japan and Korea, were prepared tentatively and stored at $35^{\circ}C$ for $3\sim4$ months to test their keeping quality. Headed, eviscerated, ana skinned filefish were purchased from Tokyo central wholesale market and filleted. The fillets were seasoned with the seasoning powder prepared from sugar, sorbitol, salt, glutamate, 5'-ribonucleotide, and either beef flavor (Flava-Beef, Kyowa Hakko Kogyo Co. Ltd.), red pepper, or smoke flavor (Smok-EZ, Alpha Foods Co. Ltd.). After seasoning, the fillets were dried at $39\sim41^{\circ}C$ for several hours, vacuum-packed in the bag of plastic film, and cooked in water of $80^{\circ}C$ for 40 min. Two kinds of products different in moisture level were prepared : one containing moisture of $26\sim29\%$ and the other $40\sim46\%$. The moisture level, water activity, color value (L,a, and b values), texture, and viable counts of bacteria of these products were determined during storage at $35^{\circ}C$. From the results obtained, it became clear that the products could be preserved in good condition for $3\sim4$ months at $35^{\circ}C$, though they slightly decreased in the softness with decrease of moisture content and developed a pale brown during storage. Judging from organoleptic evaluation on the flavor, the products containing beef flavor as a seasoning was most desirable.

• Journal of the Korean Vacuum Society
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• v.21 no.5
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• pp.233-241
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• 2012

We have deposited the bilayer consisted of the underlayer and the overlayer by using DC magnetron sputter on Single crystal MgO (001) substrate. This bilayer was fabricated at fixed annealing temperature and time. We have controlled agglomeration effect by changing of the bilayer thickness. Finally, we have made the self-organization and nano-structured film. In this processing, we have made nano-dot which consists of the underlayer and the overlayer, unlike the existing method called the agglomeration effect in the single layer. The underlayer has deposited using Ti, Cr and Co. And the overlayer has deposited with Ag. Through the analysis of Atomic force microscopy (AFM), the microstructure of underlayer is observed by AFM to confirm the formation of nano-dot. As the nano-dot through above processing, we have found that the nano-dot has the different shape. As a result, when we manufactured nano-dot through the agglomeration effect of bi-layer, the best matching material is Ti for underlayer. And also, we have found that MgO/Ti/Ag samples have been grown expitaxially toward the direction of MgO (001) by X-ray Diffraction analysis.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.1
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• pp.20-26
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• 2001

Titanium boride ($\textrn{TiB}_{x}$) films were deposited on (100) silicon substrates at the substrate temperature of $500^{\circ}C$ by means of the co-evaporation of titanium and boron evaporants during deposition. The co-evaporation method makes it possible to deposit the non-stoichiometric films with different boron-to-titanium ratio($0{\le}B/Ti \le 2.5$). The resistivity increases linearly as the boron-to-titanium ratio in the as-deposited films is increased. The surface roughness of $\textrn{TiB}_{x}$ films is changed as a function of the boron-to-titanium ratio. The XRD spectrum for pure titanium film shows a highly (002) preferred orientation. For B/Ti=0.59 ratio only a single TiB phase that shows a (111) preferred orientation is observed. However, the $\textrn{TiB}_{x}$ phase with the hexagonal structure of the $AlB_2$(C32) type appears as the boron concentration increase, and only a single $\textrn{TiB}_{x}$ phase is observed for $B/Ti \ge 2.0$ ratio. The $\textrn{TiB}_{x}$/Si samples reveal a tensile stress (3~$20{\times}^9$dyn/$\textrm{cm}^2$) in the overall composition of the films, although the magnitude of the residual stresses is depended on the nominal B/Ti ratio.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.6
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• pp.282-287
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• 2009

$Ni_xFe_{100-x}$ films with a thickness of about 100nm were deposited on Si(100) substrates at room temperature by a DC magnetron co-sputtering using Fe and Ni targets. Compositional, structural, electrical and magnetic properties of the films were investigated. $Ni_{67}Fe_{33}$, $Ni_{55}Fe_{45}$, $Ni_{50}Fe_{50}$, $Ni_{45}Fe_{55}$, $Ni_{40}Fe_{60}$ films are obtained by increasing the sputtering power of the Fe target. The films of x < 55 have BCC structure and show the phase transformation after annealing at the range of $300{\sim}450^{\circ}C$ for 2 h. On the other hand, the films of x < 50 have the mixed crystalline phases of BCC and FCC after the annealing treatment. The saturation magnetization was decreased initially by the phase transformation effect but then increased again after annealing at $450^{\circ}C$ due to the grain growth and crystallization of BCC phases.

• Applied Chemistry for Engineering
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• v.31 no.3
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• pp.291-298
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• 2020

ZITO/Ag/ZITO multilayer transparent electrodes at room temperature on glass substrates were prepared using RF/DC magnetron sputtering. Transparent conductive films with a sheet resistance of 9.4 Ω/㎡ and a transmittance of 83.2% at 550 nm were obtained for the multilayer structure comprising ZITO/Ag/ZITO (100/8/42 nm). The sheet resistance and transmittance of ZITO/Ag/ZITO multilayer films meant that they would be highly applicable for use in polymer-dispersed liquid crystal (PDLC)-based smart windows due to the ability to effectively block infrared rays (heat rays) and thereby act as an energy-saving smart glass. Effects of the thickness of the PDLC layer and the intensity of ultraviolet light (UV) on electro-optical properties, photopolymerization kinetics, and morphologies of difunctional urethane acrylate-based PDLC systems were investigated using new transparent conducting electrodes. A PDLC cell photo-cured using UV at an intensity of 2.0 mW/c㎡ with a 15 ㎛-thick PDLC layer showed outstanding off-state opacity, good on-state transmittance, and favorable driving voltage. Also, the PDLC-based smart window optimized in this study formed liquid crystal droplets with a favorable microstructure, having an average size range of 2~5 ㎛ for scattering light efficiently, which could contribute to its superior final performance.

• Journal of Mushroom
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• v.16 no.3
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• pp.131-139
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• 2018

The king oyster mushroom (Pleurotus eryngii) is widely consumed because of its flavor, texture, and its functional properties such as antioxidant activity and prebiotic effects. However, long-term product storage and transportation (e.g., export) are difficult because of its limited durability. The shelf-life of king oyster mushroom is affected by environmental factors such as temperature, humidity, gas composition, and ventilation, which may affect sensory characteristics including respiration rate, texture, moisture, flavor, color, and pH. The major problems regarding storage of mushrooms are browning, flavor changes, and softening. To address these problems, novel preservation techniques were developed, and more durable variants were bred. Different drying methods, gamma irradiation, chitosan coating, modified atmosphere (MA) packaging, and controlled atmosphere (CA) storage were evaluated in order to extend the shelf-life of king oyster mushrooms. Freeze drying showed better results for the preservation of mushrooms than other drying methods. Irradiation with 1 kGy was more effective for extending mushroom shelf-life than higher doses. The preservative performance of chitosan-based films was improved by combining the compound with other hydrocolloids, such as oil, protocatechuic acid, and wax. The CA storage conditions recommended for king oyster mushrooms are 5kPa $O_2$ and 10 to 15kPa $CO_2$ at temperatures below $10^{\circ}C$. Active MA packaging with microperforated PP film was also effective for maintaining quality during storage.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.12 no.2
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• pp.117-123
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• 2006

To mass-product useful biopolymer films, chitosan/gelatin blend films were prepared by solution casting method. Effect of mixing ratio, tensile strength(TS), elongation(${\Delta}E$) at break, total color difference(E), water vapor permeability(WVP) and oxygen permeability(OP) on chitosan/gelatin blend films properties were investigated. TS, ${\Delta}E$, E, WVP and OP values of chitosan/gelatin blend films were 43.43-38.30 MPa, 9.02-15.09%, 1.28-3.81, $0.8420-0.9673ng{\cdot}m/m^2{\cdot}s{\cdot}Pa$ and $1.5472{\times}10^{-7}-1.5424{\times}10^{-7}mL{\cdot}{\mu}m/m^2{\cdot}s{\cdot}Pa$, respectively. TS of the blend films decreased, while E and E of the blend films increased with increasing chitosan content. WVP and OP of the blend films did not show any significant relationship with mixing ratio and thickness of the blend films. OP of the blend films were lower than those of low density polyethylene and oriented polypropylene.