• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.819-822
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• 2021

To enhance phage endolysin-mediated cell wall disruption of Escherichia coli O157:H7, the cells were co-treated with aromatic compounds, namely thymol or eugenol, found in essential oils and endolysin LysECP26. Interestingly, the minimal inhibitory concentrations of LysECP26 was four times lower when used in combination with either of the two compounds than when it was used alone. This synergistic activity was also confirmed by viable cell counting. Within 1 h of LysECP26 and eugenol or thymol co-treatment to the cells, there was a 2.3 or 3.8 log CFU/mL reductions, respectively. Additionally, field emission scanning electron microscopy showed cell wall disruption and severe morphological alterations of the cells in case of the combination treatments. Therefore, endolysin and thymol or eugenol co-treatment can help in developing efficient bio-control strategies against gram-negative pathogen E. coli O157:H7.

• Journal of Surface Science and Engineering
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• v.52 no.3
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• pp.130-137
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• 2019

In this study, the cobalt sulfide (CoS) nanosheet on stainless steel as a supercapacitor electrode is synthesized by using a facile successive ionic layer adsorption reaction (SILAR) method. The number of cycles for dipping and rinsing can control the nanosheet thickness of CoS on stainless steel. Field emission-scanning electron microscopy (FE-SEM) showed a layer structure of CoS particles coupled as agglomeration. And x-ray diffraction (XRD) showed the crystallinity of the CoS nanosheet. To investigate the characteristics of the CoS nanosheet electrode as the supercapacitor, analysis of electrochemical measurement was conducted. Finally, the CoS nanosheet of 70cycles on stainless steel shows the specific capacitance ($44.25mF/cm^2$ at $0.25mA/cm^2$) with electrochemical stability of 78.5% over during 2000cycles.

• Journal of the Semiconductor & Display Technology
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• v.17 no.2
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• pp.71-75
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• 2018

In this study, we prepared OLED cell with ITO (Indium Tin Oxide) films grown on the glass substrate by facing targets sputtering. Before fabrication of OLED cells, we investigated properties of ITO films deposited at various sputtering conditions. To investigate properties of as-prepared films, we employed four-point probe, UV-VIS spectrometer, X-ray diffractometer (XRD), field emission scanning electron microscopy (FE-SEM), hall-effect measurement. As a results, as-prepared ITO films have high transmittance of over 85 % in the visible range (300-800 nm) and a resistivity of under $10^{-4}$ (${\Omega}-cm$). Their resistivity increased as a function of oxygen gas flow and substrate temperature. OLED cell with ITO films were fabricated by thermal evpoeartor. Properties of OLEDs cell referring to properties of ITO films.

• Mycobiology
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• v.47 no.2
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• pp.250-255
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• 2019

In the present study, we aimed to determine the cause of surface film formation in three rice vinegars fermented using the traditional static fermentation method. The pH and total acidity of vinegar were 3.0-3.3 and 3.0-8.7%, respectively, and acetic acid was the predominant organic acid present. Colonies showing a clear halo on GYC medium were isolated from the surface film of all vinegars. Via 16S rDNA sequencing, all of the isolates were identified as Acetobacter pasteurianus. Furthermore, field-emission scanning electron microscopy analysis showed that the bacterial cells had a rough surface, were rod-shaped, and were ${\sim}1{\times}2{\mu}m$ in size. Interestingly, cells of the isolate from one of the vinegars were surrounded with an extremely fine threadlike structure. Thus, our results suggest that formation of the surface film in rice vinegar was attributable not to external contamination, to the production of bacterial cellulose by A. pasteurianus to withstand the high concentrations of acetic acid generated during fermentation. However, because of the formation of a surface film in vinegar is undesirable from an industrial perspective, further studies should focus on devising a modified fermentation process to prevent surface film formation and consequent quality degradation.

• Elastomers and Composites
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• v.53 no.4
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• pp.202-206
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• 2018

Five solution styrene butadiene rubber/neodymium butadiene rubber (SSBR/NdBR) composites were manufactured using different ratios of SSBR and NdBR. In this study, the composites were reinforced with NdBR and silica to confirm the physical properties of SSBR used for treads of automobile tires and the dispersibility with silica. The morphologies of the rubber composites were observed using field-emission scanning electron microscopy (FE-SEM). The crosslinking behaviors of the composites were tested using a rubber process analyzer (RPA), and the abrasion resistances were tested using a National Bureau of Standards (NBS) abrasion tester. The hardness values, tensile strengths, and cold resistances of the composites were also tested according to ASTM standards. Increased NdBR content yielded composites with excellent crosslinking properties, abrasion resistances, hardnesses, tensile strengths, and cold resistances. The crosslinking point increased due to the double bond in NdBR, thereby increasing the degree of crosslinking in the composites. The NdBR-reinforced composites exhibited excellent abrasion resistances, which is explained as follows. In SSBR, a breakage is permanent because a resonance structure between styrene and SSBR forms when the molecular backbone is broken during the abrasion process. However, NdBR forms an additional crosslink due to the breakdown of the molecular backbone and high reactivity of the radicals produced. In addition, the low glass transition temperature (Tg) of NdBR provided the rubber composites with excellent cold resistances.

• Korean Journal of Materials Research
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• v.31 no.12
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• pp.672-676
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• 2021

In this paper, the effect of Ni (0, 0.5 and 1.0 wt%) additions on the microstructure, mechanical properties and electrical conductivity of cast and extruded Al-MM-Sb alloy is studied using field emission scanning electron microscopy, and a universal tensile testing machine. Molten aluminum alloy is maintained at 750 ℃ and then poured into a mold at 200 ℃. Aluminum alloys are hot-extruded into a rod that is 12 mm in diameter with a reduction ratio of 39:1 at 550 ℃. The addition of Ni results in the formation of Al₁₁RE₃, AlSb and Al3Ni intermetallic compounds; the area fraction of these intermetallic compounds increases with increasing Ni contents. As the amount of Ni increases, the average grain sizes of the extruded Al alloy decrease to 1359, 536, and 153 ㎛, and the high-angle grain boundary fractions increase to 8, 20, and 34 %. As the Ni content increases from 0 to 1.0 wt%, the electrical conductivity is not significantly different, with values from 57.4 to 57.1 % IACS.

• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.366-370
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• 2022

A 12 ㎛ pixel-sized 360 × 240 microbolometer focal plane array (MBFPA) was fabricated using a complementary metaloxide-semiconductor (CMOS)-compatible process. To release the MBFPA membrane, an amorphous carbon layer (ACL) processed at a low temperature (<400 ℃) was deposited as a sacrificial layer. The thermal time constant of the MBFPA was improved by using serpentine legs and controlling the thickness of the SiNx layers at 110, 130, and 150 nm on the membrane, with response times of 6.13, 6.28, and 7.48 msec, respectively. Boron-doped amorphous Si (a-Si), which exhibits a high-temperature coefficient of resistance (TCR) and CMOS compatibility, was deposited on top of the membrane as an IR absorption layer to provide heat energy transformation. The structural stability of the thin SiNx membrane and serpentine legs was observed using field-emission scanning electron microscopy (FE-SEM). The fabrication yield was evaluated by measuring the resistance of a representative pixel in the array, which was in the range of 0.8-1.2 Mohm (as designed). The yields for SiNx thicknesses of SiNx at 110, 130, and 150 nm were 75, 86, and 86%, respectively.

• Journal of Surface Science and Engineering
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• v.55 no.2
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• pp.70-76
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• 2022

In this paper, we compared the properties of the chromium nitride (CrN) films prepared by inductively coupled plasma magnetron sputtering (ICPMS). As a comparison, CrN film prepared by a direct current magnetron sputtering (dcMS) is also studied. The crystal structure, surface and cross-sectional microstructure and composite properties of the as-deposited CrN films are compared by x-ray diffraction, field emission scanning electron microscopy, nanoindentation tester and corrosion resistance tester, respectively. It is found that the as-deposited CrN films by ICPMS grew preferentially on (200) plane when compared with that by dcMS on (111) plane. As a result, the films deposited by ICPMS have a very compact microstructure with high hardness: the nanoindentation hardness reached 19.8 GPa and 13.5 GPa by dcMS, respectively. Besides, the residual stress of CrN films prepared by ICPMS is also relatively large. After measuring the corrosion resistance, the corrosion current of films prepared by ICPMS was three order of magnitude smaller than that of CrN films deposited by dcMS.

• Journal of Powder Materials
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• v.29 no.6
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• pp.485-491
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• 2022

Lithium lanthanum titanium oxide (LLTO) is a promising ceramic electrolyte because of its high ionic conductivity at room temperature, low electrical conductivity, and outstanding physical properties. Several routes for the synthesis of bulk LLTO are known, in particular, solid-state synthesis and sol-gel method. However, the extremely low ionic conductivity of LLTO at grain boundaries is one of the major problems for practical applications. To diminish the grain boundary effect, the structure of LLTO is tuned to nanoscale morphology with structures of different dimensionalities (0D spheres, and 1D tubes and wires); this strategy has great potential to enhance the ion conduction by intensifying Li diffusion and minimizing the grain boundary resistance. Therefore, in this work, 0D spherical LLTO is synthesized using ultrasonic spray pyrolysis (USP). The USP method primarily yields spherical particles from the droplets generated by ultrasonic waves passed through several heating zones. LLTO is synthesized using USP, and the effects of each precursor and their mechanisms as well as synthesis parameters are analyzed and discussed to optimize the synthesis. The phase structure of the obtained materials is analyzed using X-ray diffraction, and their morphology and particle size are analyzed using field-emission scanning electron microscopy.

• Corrosion Science and Technology
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• v.22 no.2
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• pp.99-107
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• 2023

Layered silicate clay montmorillonite (MMT) has been used in nanocomposite coating to improve corrosion protection by reinforcing the barrier property. The better dispersion of MMT in the coating produces a higher barrier effect. Pretreatment with MMT could favor the delamination of clay platelets, facilitating MMT dispersion in the coating. In the present work, a montmorillonite/silica (MMT/Si) composite was prepared by the in situ sol-gel method. x-ray diffraction measurements and field-emission scanning electron microscopy observations showed silica crystal formation and increased basal spacing between the MMT platelets. Composite MMT/Si particles were introduced in an epoxy resin to reinforce the corrosion protection of the coating applied on the AA2024 surface. Electrochemical impedance spectroscopy (EIS) was performed to characterize the protective property of the coating. The results demonstrated the high barrier effect of the coating containing 5 wt% of MMT/Si. Adhesion evaluation after a salt spray test exhibited a high adherence to the epoxy coating containing MMT/Si.