• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.107-111
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• 2005

We have performed a study on the electrochemical characteristics and nuclear ($^7Li$) magnetic resonance of $V_2O_5$ xerogels that have been synthesized by the sol-gel reaction of $V_2O_5$ powder with hydrogen peroxide. NMR measurements revealed that chemical shift of $Li^+$ ions varied as lithium ions were inserted into $V_2O_5$ xerogel and that several different sites for $Li^+$ ions existed in the $V_2O_5$ xerogel structure. The electrochemical properties of the xerogel electrodes did not depend much upon the concentration of $V_2O_5$ and HCl that were used for the synthesis of $V_2O_5$ gels. The specific capacity of $V_2O_5$ xerogels were about 140 mAh/g, similar to that of the xerogels prepared by the ion exchange method.

• Microbiology and Biotechnology Letters
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• v.51 no.1
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• pp.37-42
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• 2023

Neutral and non-essential amino acid, glutamine (Gln), plays an essential role in supplying nitrogen to all the amino acids and nucleotides in the mammalian body. Gln is also the most important carbon source that provides intermediates for gluconeogenesis and fatty acid synthesis and supplements the tricarboxylic acid cycle in fast-growing cancer cells. Among the known 14 Gln transporter genes, soluted carrier family 1 member 5 (SLC1A5) has been reported to be closely associated with cancer cell growth. Three variants (v1, v2, and v3) have been derived from SLC1A5. Here, we established a heterologous gene expression system for the active form of human SLC1A5 variant-2 (hSLC1A5v2) in Escherichia coli. v2 is the smallest variant that has not yet been studied. Four expression systems were investigated: pBAD, pCold, pET, and pQE. We also addressed the problem of codon usage bias. Although pCold and pET overexpressed hSLC1A5v2 in E. coli, they were functionally inactive. hSLC1A5v2 using the pBAD system was able to catalyze the successful transport of Gln, even if it was not highly expressed. Initial activity of hSLC1A5v2 for [¹⁴C] Gln uptake in E. coli reached up to 6.73 μmole·min^-1·gDW^-1 when the cell was induced with 80 mM L-arabinose. In this study, we demonstrated a heterologous expression system for the human membrane protein, SLC1A5, in E. coli. Our results can be used for the functional comparison of SLC1A5 variants (v1, v2, and v3) in future studies, to facilitae the developement of SLC1A5 inhibitors as effective anticancer drugs.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.239-244
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• 2013

This paper presents a design of the CMOS LDO regulator with a UVLO protection function for a high speed PMIC. Proposed LDO regulator circuit consists of a BGR reference circuit, an error amplifier and a power transistor and so on. UVLO block between the power transistor and the power supply is added for a low input protection function. Also, UVLO block showed normal operation with turn-off voltage of 2.7V and turn-on voltage of 4 V in condition of 5 V power supply. Proposed circuit generated fixed 3.3 V from a supply of 5V. From SPICE simulation results using a $1{\mu}m$ high voltage CMOS technology, simulation results were 5.88 mV/V line regulation and 27.5 uV/mA load regulation with load current 0 mA to 200 mA.

• Particle and aerosol research
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• v.16 no.4
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• pp.95-105
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• 2020

Vanadium Pentoxide (V2O5) has been emerged as alternative electrode materials for supercapacitors due to their low cost, natural abundance, and environmental friendliness. Graphene (GR) loaded with V2O5 can exhibit enhanced specific capacitance. In this study, we present three-dimensional (3D) crumpled graphene (CGR) decorated with V2O5. The V2O5-graphene composites were synthesized from a colloidal mixture of graphene oxide (GO) and Ammonium metavanadate (NH4VO3), via aerosol spray drying and post heat treatment process. The average size of composite was ranged from 1.82 to 4.6 ㎛. Morphology of the composite changed from a crumpled paper ball to spherical ball having relatively smooth surface as the content of V2O5 increased in the composites. The electrochemical performance of the V2O5-graphene composites was examined. The V2O5-graphene composite electrode showed the specific capacitance of 312 F/g. In addition, the device possessed acceptable cyclic stability, with 84% after 2000 cycles at 2 A/g. These outstanding properties are expected to make the composites prepared in this study as promising electrode materials for supercapacitor applications.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.8
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• pp.652-657
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• 2001

Vanadate glasses containing 10~20mol% glass former, P$_2$O$_{5}$ were prepared by melting the batch in platinum crucible and quenching on the copper plate. Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ glass-ceramics having LiV$_3$O$_{8}$ were obtained by heat-treatment of this glass in crystallization temperature. The glass-ceramics showed singnificantly good capacity and long cycles life according to heating condition. In this paper, we described electrochemical properties during crystallization process and found the best crystallizaton condition of Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ glass as cathode material. Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ glass-ceramics heat-treated at 233$^{\circ}C$ for 3 hors showed good rechargeable capacity of 220mAh/g in the cycling range between 2.0 and 3.9V.en 2.0 and 3.9V.

• Korean Journal of Materials Research
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• v.5 no.7
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• pp.802-807
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• 1995

The electrochromic properties of vacuum deposited V$_2$O$_{5}$ thin films as a function of crystallinity and film thickness have been systematically investigated. The as-deposited films have slightly yellow appearance. V$_2$O$_{5}$ films deposited at higher substrate temperature(>14$0^{\circ}C$) are found to be crystalline while those deposited at low substrate temperature are amorphous. The optical modulation on lithium ion injection indicates that V$_2$O$_{5}$ films exhibit anodic coloration in the 300~500 nm wavelength range and cathodic coloration in the 500~1100nm wavelength range independent of crystallinity and film thickness. The optical band gap energy of crystalline and amorphous Li$_{x}$ VV$_2$O$_{5}$ films shifts to higher energies by 0.17 eV and 0.75 eV, respectively, with increasing lithium ion injection up to x=0.6. The coloration efficiency of amorphous Li$_{x}$ V$_2$O$_{5}$ exhibits very little dependence on film thickness and lithium ion injection amounts in the near-infrared while it increases significantly with increasing film thickness and decreasing lithium ion injection amounts in the blue and near-UV due to the shift in absorption edge below around 500nm. However, the coloration efficiency of crystalline Li$_{x}$ V$_2$O$_{5}$is relatively independent of film thickness and lithium ion injection in the 300~1100 nm wavelength range.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.661-663
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• 2004

In this paper, we have investigated characteristics of C-V for double gate MOSFET with main gate and side gate by the variation of side sate length and side gate voltage. Main gate voltage is changed from -5V to +5V. We know that characteristics of C-V is good under the condition of LSG=70nm, VSG=3V, VD=2V. We have analyze characteristics of device by ISE-TCAD.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.28-31
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• 1994

We have investigated the characterization of $V_2O_{5}$ thin films as a counter electrode for lithium based complementary electrochromic devices. The amorphous $V_2O_{5}$ thin films produces comparatively small changes in transmittance in the visible and near infrared compared to the crystalline $V_2O_{5}$ thin films, while the degradation occurs in a-$V_2O_{5}$ thin films with increasing the cycle life time. As the thickness of $V_2O_{5}$ thin films increases from 100 to 600 nm, the magnitude of transmittance modulation decreases. The crystalline $V_2O_{5}$ thin films with thickness around 1000 have electrochromic properties suitable for counter electrode application in lithium based electrochromic smart windows.

• Journal of the Korean Magnetics Society
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• v.13 no.3
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• pp.109-114
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• 2003

The purpose of this study Is to investigate the effect of $V_2$O$_{5}$ addition on the microstructures and magnetic properties of 7.7${\times}$4.5${\times}$1.0 mm sized multi-layer chip inductors prepared by the screen printing method using 0∼0.5 wt％ $V_2O_{5}$-doped NiCuZn ferrite pastes. With increasing the $V_2O_{5}$ content, the exaggerated grain growth of ferrite layers was developed due to the promotion of Ag diffusion and Cu segregation into the grain boundaries oi ferrites, which affected significantly the magnetic properties of the chip inductors. After sintering at $900^{\circ}C$, the inductance at 10 MHZ of the 0.5 wt％ $V_2O_{5}$-doped chip inductor was 3.7 ${\mu}$H less than 4.2 ${\mu}$H of the 0.3 wt% $V_2O_{5}$-doped one, which was thought to be caused by the residual stress at the ferrite layers increased with the promotion of Ag diffusion and Cu segregation. The quality factor of the 0.5 wt% $V_2O_{5}$-doped chip inductor decreased with increasing the sintering temperature, which was considered to be caused by the electrical resistivity of the ferrite layer decreased with the promotion of Ag/cu segregation at the grain boundaries and the growth of the mean grain size of ferrite due to exaggerated grain growth of ferrite layers.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.163-169
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• 2017

The purpose of this study was to estimate the antimicrobial activity of Maesil (Japanese apricot, Prunus mume) extract against Vibrio vulnificus. The strains tested in the study were 28 V. vulnificus isolates originated from fish, seawater, mud flat and seawater in fish restaurant. The vvhA gene was detected using real-time PCR and biochemical identification expressed above good identification in 28 isolates of V. vulnificus. All of V. vulnificus used in this study was susceptible to tetracycline and chloramphenicol antibiotics. These two antibiotics were considered to be useful for the treatment of patients. Maesil extracts 2.5% and 5% showed antimicrobial activity against V. cholerae NCCP 13589 and V. parahemolyticus NCCP 11143. V. vulnificus isolate and V. vulnificus NCCP 11135 showed growth inhibition at 1.25%, 2.5% and 5% of Maesil extract, respectively. Compared with V. cholerae and V. parahemolyticus, the antibacterial activity of Maesil extract against V. vulnificus was high. The minimum bactericidal concentration of Maesil extract for V. vulnificus was 1.6%. These results revealed that Maesil extract was found to be very useful for inhibiting the growth of V. vulnificus and can be expected to prevent food poisoning caused by V. vulnificus.