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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Applied Science and Convergence Technology
Journal Basic Information
Journal DOI :
The Korean Vacuum Society
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Volume & Issues
Volume 24, Issue 6 - Nov 2015
Volume 24, Issue 5 - Sep 2015
Volume 24, Issue 4 - Jul 2015
Volume 24, Issue 3 - May 2015
Volume 24, Issue 2 - Mar 2015
Volume 24, Issue 1 - Jan 2015
Selecting the target year
Introduction to Helium Leak Detection Techniques for Cryogenic Systems
Kim, Heetae ; Chang, Yong Sik ; Kim, Wookang ; Jo, Yong Woo ; Kim, Hyung Jin ;
Applied Science and Convergence Technology, volume 24, issue 4, 2015, Pages 77~83
DOI : 10.5757/ASCT.2015.24.4.77
Many welding processes are performed to construct cryogenic system. Leak-tight for the cryogenic system is required at low temperature environment. Helium leak detection techniques are commonly used to find leak for the cryogenic system. The helium leak detection techniques for spraying, sniffing and pressurizing techniques are introduced. High vacuum is also necessary to use helium leak detector. So, types of fluid flow, effective temperature, conductance and pumping speed are introduced for vacuum pumping. Leak test procedure is shown for pipe welding, cryomodule and low temperature test. Cryogenic seals which include copper gasket, helicoflex gasket and indium are investigated.
Vacuum Characteristic of a Chamber Made of Mild Steel
Park, Chongdo ; Ha, Taekyun ; Cho, Boklae ;
Applied Science and Convergence Technology, volume 24, issue 4, 2015, Pages 84~89
DOI : 10.5757/ASCT.2015.24.4.84
The base pressure and outgassing rate of a mild steel chamber were measured and compared to those of a stainless steel chamber. A combined sputter-ion and non-evaporable getter pump with a nominal pumping speed of 490 l/s generated the base pressure of
mbar in the mild steel chamber and
mbar in the stainless steel chamber. The rate-of-rise measurements show that the mild steel has an extremely low outgassing rate of
, which is about one-order of magnitude smaller than the outgassing rate of the stainless steels. Vacuum annealing of the mild steel at
reduced the outgassing rate further to
, which was comparable to the outgassing rate of a heat treated stainless steel for extreme-high vacuum use.
The Study on the Precursor Adsorption using in-situ Nanoparticle-assisted Attenuated Total Reflectance Infrared Spectroscopy
Shin, Jae-Soo ; Park, Myung-Su ; Jung, Won-Jun ; Park, Hee-Jung ; Yun, Ju-Young ; Kim, TaeWan ; Kang, Sang-Woo ;
Applied Science and Convergence Technology, volume 24, issue 4, 2015, Pages 90~95
DOI : 10.5757/ASCT.2015.24.4.90
The adsorption behavior of tris (dimethylamino)-cyclopentadienyl-zirconium (Cp-Zr) precursor using an in-situ attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FT-IR) was studied. In attempt to improve the detection intensity of an adsorbed precursor, nanoparticles were uniformly distributed on the Ge ATR crystal surface employing the spray method. The absorption characteristics studies were carried out over the Ge crystal temperature in the range of
. Upon increasing the temperature, a reduction of absorption was observed. Based on the peak intensities of ATR-FT-IR spectroscopy, higher-
absorption efficiency occurs when the nano-particles are utilized compared to pure Ge crystal.
Quantitative Evaluation on Photocatalytic Activity of Anatase TiO
Nanocrystals in Aqueous Solution
Jeon, Byungwook ; Kim, Yu Kwon ;
Applied Science and Convergence Technology, volume 24, issue 4, 2015, Pages 96~101
DOI : 10.5757/ASCT.2015.24.4.96
Quantitative evaluation of photocatalytic activity of oxide nanoparticles in aqueous solution is quite challenging in that the kinetic reaction rate is determined by a complicated interplay among various limiting factors such as light scattering and absorption, diffusion and adsorption of reactants in condensed liquid phase, photoexcited charge separation and recombination rate, and the exact nature of active sites determined by detailed morphology and crystallinity of nanocrystals. Here, we present our simple experimental results showing that the kinetic regime of a typical photocatalytic degradation experiment over UV-irradiated
nanoparticles in aqueous solution is in that dominated by the photoactivity of
and its concentration. This result lays a firm ground of using the measured kinetic reaction rate in evaluating photocatalytic efficiency of oxide nanocrystals under evaluation.
Numerical Modeling of Floating Electrodes in a Plasma Processing System
Joo, Junghoon ;
Applied Science and Convergence Technology, volume 24, issue 4, 2015, Pages 102~110
DOI : 10.5757/ASCT.2015.24.4.102
Fluid model based numerical analysis is done to simulate a plasma processing system with electrodes at floating potential.
is a function of electron temperature, electron mass and ion mass. Commercial plasma fluid simulation softwares do not provide options for floating electrode boundary value condition. We developed a user subroutine in CFD-ACE+ and compared four different cases: grounded, dielectric, zero normal electric field and floating electric potential for a 2D-CCP (capacitively coupled plasma) with a ring electrode.
Direct Comparison of Optical Properties from Graphene Oxide Quantum Dots and Graphene Oxide
Jang, Min-Ho ; Ha, Hyun Dong ; Seo, Tae Seok ; Cho, Yong-Hoon ;
Applied Science and Convergence Technology, volume 24, issue 4, 2015, Pages 111~116
DOI : 10.5757/ASCT.2015.24.4.111
The graphene oxide (GO) and graphene oxide quantum dots (GOQDs), which have gained research interest as new types of light-emitting materials, were synthesized by the modified Hummers method for oxidation of graphite flake and graphite nanoparticle. The optical properties of GO and GOQDs have been compared by mean of photoluminescence (PL), PL excitation (PLE), UV-vis absorbance, and time-resolved PL. The GO have an absorption peak at 229 nm and shoulder part at 310 nm, whereas the GOQDs show broad absorption with a gradual change up without any absorption peaks. The PL emission of GOQDs and GO showed the green color at 520 nm and the red color at 690 nm, respectively. The red emission of GO showed faster PL decay time than the green emission of GOQDs. In particular, the temporal PL profile of the GO showed redshift from 560 nm to 660 nm after the pump event.
Direct Growth of Graphene on Insulating Substrate by Laminated (Au/Ni) Catalyst Layer
Ko, Yong Hun ; Kim, Yooseok ; Jung, Daesung ; Park, Seung Ho ; Kim, Ji Sun ; Shim, Jini ; Yun, Hyeju ; Song, Wooseok ; Park, Chong-Yun ;
Applied Science and Convergence Technology, volume 24, issue 4, 2015, Pages 117~124
DOI : 10.5757/ASCT.2015.24.4.117
A direct growth method of graphene on insulating substrate without catalyst etching and transfer process was developed using Au/Ni/a-C catalyst system. During the growth process, behavior of the Au/Ni catalyst was investigated using EDX, XPS, SEM, and Raman spectroscopy. The Au/Ni catalyst layer was evaporated during growth process of graphene. The graphene film was composed mono-layer flakes. The transmittance of the graphene film was ~80.6%.