• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1491-1494
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• 2011

Lithium vanadium phosphate, $Li_3V_2(PO_4)_3$ was prepared by a simple solid state route. It was found that making a fine powder of $Li_3V_2(PO_4)_3$ by the mechanical milling is very effective for increasing the insertion/extraction of lithium from $Li_3V_2(PO_4)_3$ structure. In charge/discharge test, the ball-milled $Li_3V_2(PO_4)_3$ sample exhibited a higher initial discharge capacity of 174 mAh/g in the voltage range of 3.0-4.8 V, compared with pure $Li_3V_2(PO_4)_3$ sample (152 mAh/g). Furthermore, the ball-milled $Li_3V_2(PO_4)_3$ presented not only higher cycle retention rate after 50 cycles, but also better rate capability compared with pure sample in the whole region (0.1-7 C).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.3
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• pp.487-493
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• 1997

Ti/sic(4H) Schottky barrier diodes were fabricated. The donor concentration and the built-in potential obtained by capacitance-voltage(C-V) measurement was about $2.0{\times}10^{15}{\textrm}{cm}^{-3}$ and 0.65 V, respectively. The ideality factor of 1.07 was obtained from the slope of current-voltage(I-V) characteristics at low current density. The breakdown field under the reverse bias voltage was about $1.7{\times}10^3V/{\textrm}{cm}$ and was very high. The barrier height of Ti for SiC(4H) was 0.91 V, which was determined by the analysis of the saturation current-temperature and the C-V characteristics.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.844-849
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• 2022

The pathogenic Vibrio genus denotes halophilic bacteria that are distributed in aquatic environments, including both sea and freshwater. V. cholerae, V. vulnificus, and V. parahaemolyticus are the main species that can be potent human pathogens and the leading cause of septicemia, wound infections, and seafood borne gastroenteritis. The aim of this study was to investigate the presence of pathogenic Vibrios in seawater. We obtained a total of 80 seawater samples from the Geum River estuary area in the west coast of Korea from April to December 2021. Pathogenic Vibrios was determined using a combination of the most probable number-polymerase chain reaction (MPN-PCR) methods. The detection levels of V. cholerae, V. parahaemolyticus, and V. vulnificus in the seawater samples were 7.5%, 68.8%, and 30.0%, respectively. The quantitative results were as follows: 3.6-3.6 MPN/100 mL in V. cholerae, 3.6-3,400 MPN/100 mL in V. parahaemolyticus, and 3.6-4,300 MPN/100 mL in V. vulnificus. Overall, these results provide novel insight into the necessity for seawater sanitation in the Geum River estuary area, and could help reduce the risk of seafood-borne outbreaks caused by pathogenic Vibrios.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.231-238
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• 2013

This paper describes a DC-DC converter IC for Flat Panel Displays. In case of operate LCD devices various type of DC supply voltage is needed. This device can convert DC voltage from 6~14[V] single supply to -5[V], 15[V], 23[V], and 3.3[V] DC supplies. In order to meet current and voltage specification considered different type of DC-DC converter circuits. In this work a negative charge pump DC-DC converter(-5V), a positive charge pump DC-DC converter(15V), a switching Type Boost DC-DC converter(23V) and a buck DC-DC converter(3.3V). And a oscillator, a thermal shut down circuit, level shift circuits, a bandgap reference circuits are designed. This device has been designed in a 0.35[${\mu}m$] triple-well, double poly, double metal 30[V] CMOS process. The designed circuit is simulated and this one chip product could be applicable for flat panel displays.

• Journal of the Korean Chemical Society
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• v.8 no.4
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• pp.147-152
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• 1964

Vanadium (IV) and vanadium (V) cupferrate compositions in benzene phase were determined by molar ratio method and continuous variation method spectrophotometrically at 450$m{\mu}$ or 445$m{\mu}$ of wavelength. Compositions of vanadium (IV) cupferrates, V(IV)/Cupf, varied from 1/2 to 1/4 with the acidity of solution from which the complexes were precipitated. The complexes precipitated were vanadium(IV) cupferrate($VCupf_4$) in solution with lower pH than 1.0, and vanadyl(IV) cupferrate ($VOCupf_2$) in solution with 1.8-4.3 of pH. It was considered, however, that the complexes in solution with 1.3-1.7 of pH might be hydrogen vanadyl(IV) cupferrate ($HVOCupf_3$) or nearly equimolar mixture of $VCupf_4\;and\;VOCupf_2$ complexes. Vanadium (V) cupferrate composition did not vary with the acidity of solution from which the complexes were precipitated. In solution with lower pH than 1.8, the complex precipitated was hydrogen vanadyl (V) cupferrate, $HVO_2Cupf_2$.

• Journal of the Korean Ceramic Society
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• v.11 no.3
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• pp.19-26
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• 1974

Mechanical properties of the system PbO-B2O3-V2O5 low melting glass during crystallization by heat-treatment were investigated. Wettability of the system PbO-B2O3-V2O5 was excellent and appropriate for commercial sealing as a low melting solder glass. Crystals, during heat-treated at 30$0^{\circ}C$ of the system PbO-B2O3-V2O5 were $\beta$-4PbO.B2O3, 5PbO.4B2O3, and Pb2V2O7 mainly. The percent of crystallinity was 82$\pm$5%. Mechanical properties of the system PbO-B2O3-V2O5 were influenced not only by the differences of density and coefficient of thermal expansion and the stress induced from the difference in the density and coefficient of thermal expansion between glass phase and crystals but also crystallization conditions.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.166-168
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• 2020

MPEG 비디오 그룹은 MPEG-I 표준의 일부로 포인트 클라우드(Point Cloud) 압축을 위한 비디오 기반 포인트 클라우드 부호화(V-PCC)와 몰입형(immersive) 비디오 압축을 위한 MPEG Immersive Video(MIV) 표준을 개발하고 있다. 최근에는 포인트 클라우드 및 몰입형 비디오와 같은 체적형(volumetric) 비디오를 모두 압축할 수 있도록 V-PCC 와 MIV 를 통합한 V3C(Visual Volumetric Video-based Coding) 표준화를 진행하고 있다. 본 논문에서는 V3C 코덱을 사용한 3DoF+(3 Degree of Freedom plus) 비디오 부호화 방안을 분석한다. 또한 V3C 코덱의 2D 코덱으로 기존 HEVC 대신 VVC 를 사용할 경우의 부호화 성능 향상을 분석한다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.4
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• pp.223-229
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• 2022

In this paper, the ignition trans used in boilers was studied. Regardless of the change in the ignition rod length and the ignition rod gap, the output frequency was measured between 59.5 and 61.3 Hz, and it was found that the low frequency circuit operated normally. When the ignition rod gap changed by 2 to 10 mm, the ignition rod length was measured from 2.8A to 3.45A at 30cm. The ignition rod length was measured from 9.37 A to 14.5 A at 500 cm and from 13.2 A to 32.6 A at 1000 cm. As the ignition rod length and the ignition rod gap increased, the current increased. As a result of measuring the secondary coil output voltage. The ignition rod length was measured from AC 0.84 kV to AC 1.75 kV at 30 cm, AC 1.17 kV to AC 1.944 at 500 cm, and AC 1.4 kV to AC 7.18 kV at 1000 cm. As the ignition rod length and the ignition rod gap increased, the output voltage of the secondary coil also increased. As a result of measuring the output voltage of the ignition trans, the ignition rod length was measured from DC 1.11 kV to DC 1.57 kV at 30cm, DC 2.49 kV to DC 3.72 kV at 500cm, and DC 3.78 kV to DC 9.42 kV at 1000cm, and the power voltage increased as the ignition rod length and interval increased.

• Korean Journal of Pharmacognosy
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• v.50 no.1
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• pp.53-58
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• 2019

Morus alba fruit contains several anthocyanins and flavonoids like cyanidin-3-O-rutinoside and quercetin-3-O-rutinoside. Extractions from Morus alba fruit were performed with five different compositions of ethanol/water [v/v]. High-Performance Liquid Chromatography (HPLC) was used for the validation and content determination of cyanidin-3-O-rutinoside and quercetin-3-O-rutinoside. The contents of cyanidin-3-O-rutinoside in ethanol extracts (100%, 70%, 40%, 20% and 0%, ethanol/water [v/v]) were 1.150%, 0.822%, 0.749%, 0.663% and 0.597%, respectively. Quercetin-3-O-rutinoside contents of ethanol extracts (100%, 70%, 40%, 20% and 0%, ethanol/water [v/v]) were 0.167%, 0.161%, 0.159%, 0.155% and 0.096%, respectively. The highest contents of cyanidin-3-O-rutinoside and quercetin-3-O-rutinoside were in the ethanol extract with 100% ethanol/water [v/v]. These HPLC analysis method could be used as basic data for standardization of functional food from Morus alba fruit.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.581-588
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• 2007

To enhance the photodecomposition of concentrated ammonia into N2, Pt/V-TiO2 photocatalysts were prepared using solvothermal and impregnation methods. Nanometer-sized particles of 0.1, 0.5 and 1.0 mol% V-TiO2 were prepared solvothermally, and then impregnated with 1.0 wt% Pt. The X-ray diffraction (XRD) peaks assigned to V2O5 at 30.20 (010) and Pt metal at 39.80 (111) and 46.20 (200) were seen in the 1.0 wt% Pt/ 10.0 mol% V-TiO2. The particle size increased in the order: pure TiO2, V-TiO2 and Pt/V-TiO2 after thermal treatment at 500 °C, while their surface areas were in the reverse order. On X-ray photoelectron spectroscopy (XPS), the bands assigned to the Ti2p3/2 and Ti2p1/2 of Ti4+-O were seen in all the photocatalysts, and the binding energies increased in the order: TiO2 < Pt/V-TiO2 < V-TiO2. The XPS bands assigned to the V2p3/2 (517.85, 519.35, and 520.55 eV) and V2p1/2 (524.90 eV) in the V3+, V4+ and V5+ oxides appeared over V-TiO2, respectively, while the band shifted to a lower binding energy with Pt impregnation. The Pt components of Pt/ V-TiO2 were identified at 71.60, 73.80, 75.00 and 76.90 eV, which were assigned to metallic Pt 4f7/2, PtO 4f7/2, PtO2 4f7/2, and PtO 4f5/2, respectively. The UV-visible absorption band shifted closer towards the visible region of the spectrum in V-TiO2 than in pure TiO2 and; surprisingly, the Pt/V-TiO2 absorbed at all wavelengths from 200 to 800 nm. The addition of vanadium generated a new acid site in the framework of TiO2, and the medium acidic site increased with Pt impregnation. The NH3 decomposition increased with the amount of vanadium compared to pure TiO2, and was enhanced with Pt impregnation. NH3 decomposition of 100% was attained over 1.0 wt% Pt/1.0 mol% V-TiO2 after 80 min under illumination with 365 nm light, although about 10% of the ammonia was converted into undesirable NO2 and NO. Various intermediates, such as NO2, -NH2, -NH and NO, were also identified in the Fourier transform infrared (FT-IR) spectra. From the gas chromatography (GC), FT-IR and GC/mass spectroscopy (GC/MS) analyses, partially oxidized NO and NO2 were found to predominate over V-TiO2 and pure TiO2, respectively, while both molecules were reduced over Pt/V-TiO2.