• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1051-1057
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• 2000

Gamma irradiation was applied to develop fermented shrimp product with lower salt concentration, high sensory quality and storage stability. Shrimp was prepared with 15 and 20% of salt and fermented at $15^{\circ}C$. The sample was irradiated for 15% added salt at the 4th week and for 20% at the 6th week during fermentation with 0, 5 and 10 kGy absorbed doses. The irradiation was applied at optimum stage of fermentation determined when the content of amino nitrogen(AN) arrived approximately 400 mg%. Chemical properties such as amino nitrogen(AN), volatile base nitrogen(VBN), trimethylamine(TMA) and neutral protease activity were examined during whole fermentation. The AN, VBN, TMA and protease activity were not affected immediately after gamma irradiation. The more NaCl concentrations and irradiation dose, the less content of chemical compounds and protease activity was found. From the results of chemical properties, it was concluded that fermented shrimp with 15% of salt and irradiated at 10 kGy before optimum fermentation, or 20% and 5 kGy or above were maintained the sound quality during storage compared with the control.

• Carbon letters
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• v.17 no.1
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• pp.39-44
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• 2016

The work presented in this report was a detailed comparative study of the electrochemical response exhibited by graphite anodes in Li-ion batteries having different physical features. A comprehensive morphological and physical characterization was carried out for these graphite samples via X-ray diffraction and scanning electron microscopy. Later, the electrochemical performance was analyzed using galvanostatic charge/discharge testing and the galvanostatic intermittent titration technique for these graphite samples as negative electrode materials in battery operation. The results demonstrated that a material having a higher crystalline order exhibits enhanced electrochemical properties when evaluated in terms of rate-capability performance. All these materials were investigated at high C-rates ranging from 0.1C up to 10C. Such improved response was attributed to the crystalline morphology providing short layers, which facilitate rapid Li⁺ ions diffusivity and electron transport during the course of battery operation. The values obtained for the electrical conductivity of these graphite anodes support this possible explanation.

• Journal of the Korean Electrochemical Society
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• v.11 no.2
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• pp.95-99
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• 2008

This study has made the electrode that is coated zirconium oxide on the titanium by ESD(Electrostatic spray deposition) coating methode. It has investigated the effects of the etching method of a Ti substrate as the preparation, making of zirconium oxide film and electrochemical characteristics of the electrode that is etched on the titanium. The HCl etching develops a fine and homogeneous roughness on the Ti substrate. Fabrication and material properties of the metal oxide electrode, which is known to be so effective to generate ozone and hypochlorous acid (HOCl) as power oxidant, were studied. A proper metal oxide material is focus zirconium oxide through reference. A coating method to enhance the fabrication reproducibility of the zirconium oxide electrode was used ESD coating method by zirconium oxychloride. Zirconium oxide films on the Ti substrate were tested using SEM, XRD, Cyclic voltammetry.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2683-2688
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• 2011

Silica-manganese oxides with a core-shell structure were synthesized via precipitation of manganese oxides on the $SiO_2$ core while varying the concentration of a precipitation agent. Elemental analysis, crystalline property investigation, and morphology observations using low- and high-resolution electron microscopes were applied to the synthesized silica-manganese oxides with the core-shell structure. As the concentration of the precipitating agent increased, the manganese oxide shells around the $SiO_2$ core sequentially appeared as $Mn_3O_4$ particles, $Mn_2O_3+Mn_3O_4$ thin layers, and ${\alpha}-MnO_2$ urchin-like phases. The prepared samples were assembled as electrodes in a supercapacitor with 0.1 M $Na_2SO_4$ electrolyte, and their electrochemical properties were examined using cyclic voltammetry and charge-discharge cycling. The maximum specific capacitance obtained was 197 F $g^{-1}$ for the $SiO_2-MnO_2$ electrode due to the higher electronic conductivity of the $MnO_2$ shell compared to those of the $Mn_2O_3$ and $Mn_3O_4$ phases.

• Transactions of the Korean hydrogen and new energy society
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• v.12 no.1
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• pp.39-50
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• 2001

Vanadium based solid solution alloys have been studied as a potential negative electrode of Ni/MH battery due to their high hydrogen storage capacity. In order to improve the kinetic property of V-Ti alloy in KOH electrolyte, the ball-milling process with Ni, which has a catalytic effect of hydrogen absorption/desorption, was carried out to modify the surface properties of V-Ti-Cr alloys with high hydrogen storage capacity. Moreover, to overcome the problem of poor cycle life, V-Ti alloy substituted by Cr, V0.68 Ti0.20 Cr0.12, has been developed showing a good cycle performance (keeping about 80 % of initial discharge capacity after 200 cycles). The cycle life of surface-modified V0.68 Ti0.20 Cr0.12 alloy was improved by suppressing the formation of TiO2 layer on the alloy surface while decreasing the amount of dissolved vanadium in the KOH electrolyte. In order to promote the effect of Ni coating on the surface property of V0.68 Ti 0.20 Cr 0.12 alloy by ball-milling, filamentary-typed Ni, which has higher surface coverage area than sphere-typed Ni was used as a surface modifier. Consequently, the surface-modified V0.68 Ti0.20 Cr0.12 alloy electrode showed a improved discharge capacity of 460 mAh/g.

• Journal of the Semiconductor & Display Technology
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• v.4 no.2 s.11
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• pp.15-19
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• 2005

The organic light-emitting devices(OLEDs) based on fluorescence have low efficiency due to the requirement of spin-symmetry conservation. By using the phosphorescent material, the internal quantum efficiency can reach 100$\%$, compared to 25$\%$ in case of the fluorescent material [1]. Thus recently phosphorescent OLEDs have been extensively studied and showed higher internal quantum efficiency than conventional OLEDs. In this study, we have applied a new Ir complex as a red dopant and fabricated a red phosphorescent OLED on a flexible PC(Polycarbonate) substrate. Also, we have investigated the electrical and optical properties of the devices with a structure of A1/LiF/Alq3/(RD05 doped)BAlq/NPB/2-TNAIA/ITO/PC substrate. Our device showed the lightening efficiency of > 30 cd/A at an initial brightness of 1000 cd/$m^{2}$. The CIE(Commission Internationale de L'Eclairage) coordinates for the device were (0.62,0.37) at a current density of 1 mA/$cm^{2}$. In addition, although the sheet resistance of ITO films on PC substrate is higher than that on glass substrate, the flexible OLED showed much better lightening efficiency without much increase in operating voltage.

• Journal of Biosystems Engineering
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• v.30 no.5 s.112
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• pp.274-279
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• 2005

Impact is one of the major cause of damage to fruits druing varios processes from the production on the farm to the consumer. The tissue of fruits are ruptured in a very short period time less than 10ms by impact loading. Mechanical behavior of fruits under impact loading can be analyzed better with high speed sampling data acquisition system and one of them is a digital storage oscilloscope. A impact test system was developed to test the physical properties of fruits including apple, pear, and peach which may lead to a better understanding of the physical laws. The test system consisted of a digital storage oscilloscope and simple mechanism which can apply impact force to fresh produce. Rupture force, energy, and deffrmation were measured at the five levels of drop heights from 4 to 24cm fur each internal and external tissues. Rupture forces for apple and pear were in the range of 72.9 to 87.7 N and 70.8 to 84.1 N for external and internal tissues, respectively. Rupture forces far peach external tissues were in the range of 43.4 to 65.0 N.

• Applied Chemistry for Engineering
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• v.32 no.3
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• pp.243-252
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• 2021

With increasingly strict requirements for advanced energy storage devices in electric vehicles (EVs) and stationary energy storage systems (EES), the development of lithium-ion batteries (LIBs) with high power density and safety has become an urgent task. Because the performance of LIBs is determined primarily by the physicochemical characteristics of its electrode material, TiO₂, owing to its excellent stability, high safety levels, and environmentally friendly properties, has received significant attention as an alternative material for the replacement of commercial carbon-based anode materials. In particular, self-organized TiO₂ micro and nanostructures prepared by anodization have been intensively investigated as promising anode materials. In this review, the mechanism for the formation of anodic TiO₂ nanotubes and microcones and the parameters that influence their morphology are described. Furthermore, recent developments in anodic TiO₂-based composites as anode electrodes for LIBs to overcome the limitations of low conductivity and specific capacity are summarized.

• Journal of Electrochemical Science and Technology
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• v.12 no.4
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• pp.458-464
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• 2021

Lithium ion batteries (LIBs) is a kind of rechargeable secondary battery, developed from lithium battery, lithium ions move between the positive and negative electrodes to realize the charging and discharging of external circuits. Zeolitic imidazolate frameworks (ZIFs) are porous crystalline materials in which organic imidazole esters are cross-linked to transition metals to form a framework structure. In this article, ZIF-67 is used as a sacrificial template to prepare nano porous carbon (NPC) coated cobalt nanoparticles. The final product Co/NPC composites with complete structure, regular morphology and uniform size were obtained by this method. The conductive network of cobalt and nitrogen doped carbon can shorten the lithium ion transport path and present high conductivity. In addition, amorphous carbon has more pores that can be fully in contact with the electrolyte during charging and discharging. At the same time, it also reduces the volume expansion during the cycle and slows down the rate of capacity attenuation caused by structure collapse. Co/NPC composites first discharge specific capacity up to 3115 mA h/g, under the current density of 200 mA/g, circular 200 reversible capacity as high as 751.1 mA h/g, and the excellent rate and resistance performance. The experimental results show that the Co/NPC composite material improves the electrical conductivity and electrochemical properties of the electrode. The cobalt based ZIF-67 as the precursor has opened the way for the design of highly performance electrodes for energy storage and electrochemical catalysis.

• Korean Journal of Food Science and Technology
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• v.15 no.4
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• pp.359-363
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• 1983

Effects of irradiation on the physicochmical properties and its quality of powdered hot pepper paste which was used as a minor matrial of meat products, were investigated during the three months storage. Proximate components of powdered hot pepper paste were not remarkably changed according to the irradiation dose except the slight increase of total and reducing sugars. Capsanthin was insignificantly decreased by the increase of irradiation dose. Color difference according to the irradiation dose could not be distinguished by naked eye but was slightly changed by mechanical measurement. Total bacteria and E.coli were sterilized by the irradiation of 10kGy and 5kGy, respectively and no microorganisms were grown up after three months storage at $37^{\circ}C$. Sterilization of powered hot pepper paste by irradiation was expected to be superior to the traditional methods in the wholsomeness and sterilizing efficacy.