• Journal of the Semiconductor & Display Technology
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• v.9 no.4
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• pp.67-70
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• 2010

X-ray absorption rate and multiplication factor of X-ray detector were calculated with Garfield code. High Z (= atomic number) was important factor to increase the absorption rate but low Z is also important to increase the multiplication. Five different gas composition were examined under the condition of 1400 V bias and 400 um gap. Xe 100% gas showed the highest absorption rate and He 96% + isobutene 4% showed the highest multiplication.

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.307-311
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• 2018

Mid-range vinylidene content polyisobutylenes were prepared by using a Lewis acid catalyst. The best results were obtained when a complex catalyst composed of n-propanol as a cocatalyst and $BF_3$ as a main catalyst was used at the reaction temperature of -8 to $5^{\circ}C$ under a pressure of $2.5kg/cm^2$. The number average molecular weight ($M_n$) and viscosity of the polyisobutylenes were 500~1,000 g/mol and 20~210 cSt (at $100^{\circ}C$), respectively. The vinylidene content was 40~70% and easily varied by adjusting the reaction temperature.

• Journal of the Korean Chemical Society
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• v.7 no.2
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• pp.128-132
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• 1963

A study has been made on the applicability of gas-liquid partition chromatography to the qualitative and quantitative analysis of complex mixture of gaseous hydrocarbons. While phthalate columns are widely used for this $purpose^9$, they separates neither saturated hydrocarbons from the unsaturated nor n-butane from isobutene or butene-1, therefore combined columns such as phthalate and dimethylsulfolane have been used for the perfect separation of gaseous hydrocarbons. It is shown by this study, however, that hydrocarbons having $C_1$ through $C_4$ can be separated with a 2-meters tetraethyleneglycol dimethylether column except ethane from ethylene, and trans-from cis-2-butene especially operated at $15^{\circ}C$$ using helium as the carrier gas. The column effluents were in order of methane, (ethane, ethylene), propane, propylene, isobutane, n-butane, isobutylene, butene-1, (trans-& cis-2-butene, isopentane), (butadiene-1, 3, n-pentane). Two kinds of liquified petroleum gases in market are analysed qualitatively and quantitatively. The results indicate that use of this 2-meters TEGDE column permits the separation and identification of all the commonly encountered aliphatic gaseous hydrocarbons.

• Journal of the Korean Chemical Society
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• v.55 no.1
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• pp.81-85
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• 2011

$V_{0.9}Sb_{0.1}O_x$ systems, bulk and deposited on different supports (five types of $\gamma$-aluminas, $\alpha$-alumina, silica-alumina, silica gel, magnesium oxide), have been tested in the oxidative dehydrogenation (ODH) of iso-butane. Catalytic performance of VSb oxides has shown to be highly dependent on the support and the nature of the support decreasing in a series: $\gamma$-$Al_2O_3$ > $\alpha$-$Al_2O_3$ > Si-Al-O > $SiO_2$ $\approx$ MgO $\gg$ unsupported. Variation of the V-Sb-O-loading in the studied range of coverage (0.5-2 theoretical monolayer) only slightly influences the catalysts' activity and selectivity. The best catalytic performance of $\gamma$-alumina-supported $V_{0.9}Sb_{0.1}O_x$ systems can be explained by the optimal surface interaction between support and supported components resulting in the formation of well-spread amorphous active $VO_x$-component with vanadium in a high oxidation state.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.1964-1969
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• 2021

We developed a Dual-PPACs detector for fast neutron measurements that consists of two sets of PPAC: conventional PPAC and fission PPAC. A²³⁸U(U₃O₈) coating is placed in the fission PPAC's anode, which is used as the neutrons conversion layer. An experiment was performed to measure neutron time-of-flight (TOF) in which ²⁵²Cf spontaneous fission source was used. An excellent time resolution of 164ps has been observed at 6 mbar in isobutene gas. With the excellent time resolution of Dual-PPACs detector, exact neutron energy can be extracted from the timing measurement. The experimental detection efficiency was 1.9 × 10^-7, consistent with the efficiency of 2.5 × 10^-7 given by a Geant4 simulation. Ultimately, the results show that the Dual-PPACs detector is a suitable candidate for measuring fast neutrons in the future CiADS system.