• Journal of the Korean Chemical Society
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• v.16 no.3
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• pp.157-165
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• 1972

Thermal decomposition of ammonium metavanadate has been investigated by using the quartz spring balance and differential thermal analysis. It showed that the decomposition of ammonium metavanadate is proceeded at two stages which correspond to $180^{\circ}C-220^{\circ}C$ and $310^{\circ}C-330^{\circ}C$ decomposition temperatures, respectively. Evolved ammonia gas in thermal decomposition has been analyzed quantitatively by titration. And the constituents of gases evolved have been evaluated by gas chromatography and omegatron spectrometer. From these results, it was concluded that the gases evolved in the first step decomposition were $NH_3$ and $H_2O$ with 2:1 ratio and the second step decomposition corresponded to the formation of $NH_3$, $H_2O$ and $N_2O$ which was produced in oxidation of $NH_3$ by $V_2O_5$. The decomposition products were identified by means of X-ray diffraction method. The decomposition product in air was V_2O_5 and the product in vacuum $V_3O_7.$ The kinetics of the thermal decomposition was studied, giving the values of the activation energy of 41.4 kcal/mole and 64.4 (kcal/mole) respectively.

• Journal of the Korean Electrochemical Society
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• v.24 no.4
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• pp.113-119
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• 2021

In this study, impurity free V^3.5+ electrolytes were prepared using formic acid as a reducing agent and PtD/C as a catalyst and it was applied to VRFB. The well-oriented 3D dendrite structure of the PtD/C catalyst showed high catalytic activity in formic acid oxidation reaction and vanadium reduction reaction. As a result, the conversion ratio of electrolyte using the PtD/C was 2.73 mol g^-1 h^-1, which was higher than that of 1.67 mol g^-1 h^-1 of Pt/C prepared by the polyol method. In addition, in the VRFB charging and discharging experiment, the V^3.5+ electrolyte produced by the catalytic reaction showed the same performance as the standard V^3.5+ electrolyte prepared by the electrolytic method, thus proving that it can be used as an electrolyte for VRFB.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.41.2-41.2
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• 2011

Recently, scaling down of ULSI (Ultra Large Scale Integration) circuit of CMOS (Complementary Metal Oxide Semiconductor) based electronic devices become much faster speed and smaller size than ever before. However, very narrow interconnect line width causes some drawbacks. For example, deposition of conformal and thin barrier is not easy moreover metallization process needs deposition of diffusion barrier and glue layer. Therefore, there is not enough space for copper filling process. In order to overcome these negative effects, simple process of copper metallization is required. In this research, Cu-V thin alloy film was formed by using RF magnetron sputter deposition system. Cu-V alloy film was deposited on the plane $SiO_2$/Si bi-layer substrate with smooth and uniform surface. Cu-V film thickness was about 50 nm. Cu-V layer was deposited at RT, 100, 150, 200, and $250^{\circ}C$. XRD, AFM, Hall measurement system, and XPS were used to analyze Cu-V thin film. For the barrier formation, Cu-V film was annealed at 200, 300, 400, 500, and $600^{\circ}C$ (1 hour). As a result, V-based thin interlayer between Cu-V film and $SiO_2$ dielectric layer was formed by itself with annealing. Thin interlayer was confirmed by TEM (Transmission Electron Microscope) analysis. Barrier thermal stability was tested with I-V (for measuring leakage current) and XRD analysis after 300, 400, 500, 600, and $700^{\circ}C$ (12 hour) annealing. With this research, over $500^{\circ}C$ annealed barrier has large leakage current. However V-based diffusion barrier annealed at $400^{\circ}C$ has good thermal stability. Thus, thermal stability of vanadium-based thin interlayer as diffusion barrier is good for copper interconnection.

• Journal of the Korean Applied Science and Technology
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• v.37 no.3
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• pp.516-525
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• 2020

The densities of aqueous solutions of the amphiphile 2-(2-hexyloxyethoxy)ethanol (C₆E₂) were measured at 279.15 K and 282.15 K by vibrating-tube densitometry. Then using the density data of the binary C₆E₂ (1)/water(2) system, the excess volumes and partial molar volumes were determined at various compositions. Excess volume V^E exhibits negative deviation for the whole region of composition, which implies relatively stronger attraction between molecules. At the C₆E₂ mole fraction of around 0.45, V^E was at its minimum. Partial molar volume ${\bar{V}}_1$ increases monotonously with the mole fraction x₁(=x) and ${\bar{V}}_2$ decreases with x. Any particular point in ${\bar{V}}_1$ and ${\bar{V}}_2$, which may point to molecular association, was unobserved.

• Journal of Food Hygiene and Safety
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• v.21 no.4
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• pp.238-243
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• 2006

The populations of V. parahaemolyticus were enumerated in oysters collected in wholesale seafood markets in Seoul and tested in various possible condition. The populations of oysters soled in the markets were ranged $<2\sim1.4\times10^6$ MPN/100 g from April to November in 2005. In the case of oysters added with V. parahaemolyticus of $4\times10^3$ CFU/100 g, the highest population numbers were $1.4\times10^7$ CFU/100 g, $5.4\times10^5$ CFU/100 g and $2.7\times10^4$ CFU/100 g at $36^{\circ}C$ after culturing for 15 hours, at $25^{\circ}C$ after 15 hours and at $4^{\circ}C$ after 15 hours, respectively. But the difference of the populations of V. parahaemolticus in oysters stored in the icebox with ice for bulked sale and displayed in stalls on ice for the small packaged sale was not significant. In the case of oysters carried with ambient temperature at $30.8^{\circ}C$, the V. parahaemolyticus density was dramatically increased from $2.7\times10^5$ to $1.4\times10^8$ MPN/100 g. It was indicated it is important to carry the oysters to home with ice after purchase. Even after the washing two times with 21 tap water, the common cooking method in Korea was not greately make the decrease of V. parahaemolyticus density from $1.4\times10^8$ MPN/100 g to $9.0\times10^5$ MPN/100 g. So it is noticed to stored in low temperature after cooking, especially in hot seasons.

• Journal of the Korean Chemical Society
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• v.41 no.3
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• pp.117-122
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• 1997

On the basis of our previous paper[Bull. Korean Chem. Soc. 1995, 16, 1015], the relative stability, ionization potential, and chemical reaction of the neutral and multiply charged $C_{60}$n ions(n=3+ to 6-) have been investigated by the semi-empirical MNDO method. $C_{60}^{1-}$ has the highest stability. The ionization potential values of the $C_{60}$ ions range from 15.31 eV of $C_{60}^{2+}$ to -13.01 eV of $C_{60}^{6-}$. These values show a linear relationship according to charges. The average IP per charge is 3.15 eV from our calculations and 3.22 eV from the linear function of IP. A charge- or electron-transfer reaction of $C_{60}^{n+}$ will only occur if the ionization potential of any guest molecule is lower than the electron affinity of the host $C_{60}^{n+}$. If the energy gap between ionization potential and electron affinity, ${\Delta}_{IP-EA}$, is high, charge-transfer reactions arise by the charge-controlled effect. However, if ${\Delta}_{IP-EA}$ is low, electron-transfer reactions arise by the frontier-controlled effect.

• Korean Journal of Materials Research
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• v.8 no.7
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• pp.607-612
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• 1998

다합금계백주철의 성분원소인 Cr, V, Mo 및 W 의 첨가량을 변화시켜 응고조직을 관찰하였다. MC탄화물은 초정 austenite dendrite 내에 괴상 및 구상으로 M7C3탄화물은 intercellular boundary에 꽃형태 또는 bar 형태로, 그리고 M2C 탄화물은 M7C3탄화물과 마찬가지로 intercellular boundary에 침상으로 정출하였다. 기지조직은 주방상태에서 pealite 또는 (pearlite + austenite)의 혼합조직으로 구성되어 있었으며, 또한 EPMA 분석결과 MC탄화물은 V, M7C3 탄화물은 Cr 그리고 M2C탄화물은 Mo 및 W가 주성분으로 되어 있음을 알 수 있었다. 냉각곡선을 측정한 결과 액상에서 MC, M7C3, M2C 순으로 공정반응이 일어나고 있었으며 또한 X-선 회절시험을 통해 각 탄화물의 회절 peak를 관찰하였는바 응고조직의 사진과 잘 일치하고 있음을 알 수 있었다.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.2
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• pp.31-36
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• 2014

In this paper, we developed an intergrated piezoresistive temperature and humidity sensor using nano-technology, and evaluated the properties. In the measuring range from $20^{\circ}C$ to $80^{\circ}C$, output sensitivity of temperature was about 0.75mV/$1^{\circ}C$. Output sensitivity of humidity was about 1.35mV/10%(RH). Therefore, developed sensor suggests that it is possible applicable to the general residential environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.4
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• pp.423-430
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• 2019

The convergence of the automotive industry and the ICT technology can be broadly divided into the commercial service sector and the Cooperative-ITS (C-ITS) service sector. The C-ITS service sector is using V2X communication technology as a field that aims to provide safer transportation, more green and efficient transportation, and more predictable and productive mobility. The recent convergence of self-driving cars and connected cars requires high data rates, low transmission delays, and low transmission error rates. Interest in comparison of performance between WAVE and C-V2X (LTE-V2X, 5G-V2X) has been amplified and application services by communication technology are being studied. In this paper, we design the application performance evaluation method of Hybrid V2X communication system and confirm that the decrease of packet error rate (PER) performance is caused by the increase of communication distance, not the vehicle speed.

• Korean Journal of Agricultural Science
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• v.27 no.1
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• pp.39-47
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• 2000

A large scale field test of prefabricated vertical drains is performed to analyze the effect of parameters of the very soft clay at a test site. Compression index and the coefficient of horizontal consolidation obtained by back-analysis from the settlement data were compared with those obtained by means of laboratory tests. The Hyperbolic, Asaoka's and The Curve fitting methods are used to estimate final settlements and coefficients of consolidation. 1. Final settlement predicted with the Hyperbolic method was the largest, and the settlements predicted with the Asaoka's and the Curve fitting methods were nearly the same range, and it was concluded that smear effect has to be considered on design in the case that spacing of drains is small 2. The relationships of the measured consolidation ratio (Urn) and the designed consolidation ratio($U_t$) were showed as $U_m$ = (1.13~1.17)$U_t$, $U_m$ = (1.07~1.20)$U_t$, $U_m$ = (1.13~1.17)$U_t$ on the Hyperbolic, Asaoka's and the Curve fitting methods, respectively. The relations on the Asaoka's and the Curve fitting methods were nearly the same range. 3. The relationships of the field compression index($C_{cfield}$) and virgin compression index($V_{cclab}$) were showed as $C_{cfield}$ = (1.26~1.45)$V_{cclab}$, $C_{cfield}$ = (1.08~1.15) $V_{cclab}$, $C_{cfield}$ = (1.04~1.21)$V_{cclab}$, on the Hyperbolic, Asaoka's and the Curve fitting methods, respectively. 4. The ratio ($C_h/C_v$) of the coefficient of vertical consolidation and the coefficient of horizontal consolidation that is obtained by back-analysis from the settlement data was $C_h$=(0.7~0.9)$C_v$, $C_h$=(0.9~1.5)$C_v$, $C_h$=(2.4~3.0)$C_v$ on the Hyperbolic, Asaoka's and the Curve fitting methods, respectively. 5. It was concluded that the exact consolidation coefficient must be determined after the final settlement is predicted again when the consolidation is finished, because the field consolidation coefficient is decreased as the time allowed to be alone is increased.