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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
Editor in Chief :
Sam Kyu Noh
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
Thermal Characteristics of Rotating Anode X-ray Tube with Emissivity in Aging Process for Digital Radiography
Lee, Seok Moon ;
Applied Science and Convergence Technology, volume 24, issue 5, 2015, Pages 125~131
DOI : 10.5757/ASCT.2015.24.5.125
We investigated the thermal characteristics of rotating anode X-ray tube to develop it for digital radiography by using computer simulation. The target which is the area of the anode struck by electrons is the most important component to get a long life of X-ray tube. So we analyze the thermal characteristics of the target and rotor assembly according to their emissivity by using ANSYS transient thermal simulation and then compare with the measured data of the target temperature operating in aging process of X-ray tube. Especially, keeping the lead coated layer as the role of metal lubricant on ball bearing enables to prevent the noise in rotating anode. The simulation result showed that its temperature was under the melting point of the lead in X-ray tube for digital radiography with 1.2 mm large focal spot 0.6 mm small focal spot and 150 kV tube voltage. We also investigated the relationship between the diameter of the anode shaft and the temperature of the anode and rotor assembly. It has been confirmed that the smaller anode shaft could be good for the rotor thermal characteristics.
Vacuum Test of Cavity with Liquid Nitrogen
Choi, Suk ; Park, Gunn-Tae ; Kim, Heetae ;
Applied Science and Convergence Technology, volume 24, issue 5, 2015, Pages 132~135
DOI : 10.5757/ASCT.2015.24.5.132
Schematic of RAON vacuum system is introduced. Vacuum test for superconducting cavity with liquid nitrogen is performed. Schematic plan for RAON vacuum system is introduced and vacuum control system for superconducting cavity test is constructed. Vacuum pressure of cavity is shown as a function of pumping time. The temperature of cavity is shown as a function of cooling time. Outgassing species from cavity is also detected. Detailed experimental procedure is presented to test the cavity vacuum with liquid nitrogen.
Compact Anode Design with the Heat Capacity Performance in Rotating Anode X-ray Tube for Digital Radiography
Lee, Seok Moon ;
Applied Science and Convergence Technology, volume 24, issue 5, 2015, Pages 136~141
DOI : 10.5757/ASCT.2015.24.5.136
We studied the compact anode design to develop 100 kW rotating anode X-ray tube with large focal spot 1.2 mm, small focal spot 0.6 mm and tube voltage 150 kV for large hospital digital radiography using computer thermal simulation. The larger thermal radiation effect in a high vacuum can reduce the temperature of anode so the method to increase the surface area of anode is investigated. The anode has the multi-tier shape at the back side of TZM body of anode and also bigger diameter of anode. The number of multi-tiers was varied from 6 to 15 and the diameter of anode was also varied from
. From ANSYS transient thermal simulation result, we could obtain
anode maximum temperature when applying 100 kW input power at 0.1 second on target focal track which is less than
of the conventional 75 kW X-ray tube with reduced anode weight by 15.5% than the conventional anode. The compact anode of reduced anode weight is able to improve the unwanted noise when the rotor is rotating at high-speed and also reduce the rotational torque which the cost effective stator-coil is possible. It is believed that the anode with 15 ea multi-tiers using
can satisfy with the specification of the anode heat capacity. From the results of this paper, it has been confirmed that the proposed compact anode can be used as the anode of 100 kW rotating anode X-ray tube for digital radiography.
Failure Analysis of Filaments of Quadrupole Mass Spectrometer for Plasma Process Monitoring
Ha, Sung Yong ; Kim, Dong Hoon ; Joo, Junghoon ;
Applied Science and Convergence Technology, volume 24, issue 5, 2015, Pages 142~150
DOI : 10.5757/ASCT.2015.24.5.142
A failure analysis of tungsten filaments used in quadrupole mass spectrometer for plasma process monitoring was carried by using SEM and EDS. Failed at high temperature, filaments showed two kinds of failure modes. The one is that diameter of filament became thinner gradually and finally snapped. The other is that filament abruptly snapped almost at a right angle. The EDS analysis showed Fe and C, including W and Fe, on the surface of failed filament. when failed filaments were treated with plasma in mixture of Ar and
, the amount of Fe and C decreased. The failure analysis of filament showed that the cause of filament failure is thermal evaporation and grain growth of tungsten at high temperature.
Probing the Molecular Orientation of ZnPc on AZO Using Soft X-ray Spectroscopies for Organic Photovoltaic Applications
Jung, Yunwoo ; Lee, Nalae ; Kim, Jonghoon ; Im, Yeong Ji ; Cho, Sang Wan ;
Applied Science and Convergence Technology, volume 24, issue 5, 2015, Pages 151~155
DOI : 10.5757/ASCT.2015.24.5.151
The interfacial electronic structure between zinc phthalocyanine (ZnPc) and aluminumdoped zinc oxide (AZO) substrates has been evaluated by ultraviolet photoemission spectroscopy and angle-dependent x-ray absorption spectroscopy to understanding the molecular orientation of a ZnPc layer on the performance of small molecule organic photovoltaics (OPVs). We find that the ZnPc tilt angle improves the
interaction on the AZO substrate, thus leading to an improved short-circuit current in OPVs based on phthalocyanine. Furthermore, the molecular orientation-dependent energy level alignment has been analyzed in detail using ultraviolet photoemission spectroscopy. We also obtained complete energy level diagrams of ZnPc/AZO and ZnPc/indium thin oxide.
Diamagnetic Shift of a InGaP-AlInGaP Semiconductor Single Quantum Well under Pulsed-magnetic Fields
Choi, B.K. ; Kim, Yongmin ; Song, J.D. ;
Applied Science and Convergence Technology, volume 24, issue 5, 2015, Pages 156~161
DOI : 10.5757/ASCT.2015.24.5.156
Application of magnetic fields is important to characterize the carrier dynamics in semiconductor quantum structures. We performed photoluminescence (PL) measurements from an InGaP-AlInGaP single quantum well under pulsed magnetic fields to 50 T. The zero field interband PL transition energy matches well with the self-consistent Poisson-
equation. We attempted to analyze the dimensionality of the quantum well by using the diamagnetic shift of the magnetoexciton. The real quantum well has finite thickness that causes the quasi-two-dimensional behavior of the exciton diamagnetic shift. The PL intensity diminishes with increasing magnetic field because of the exciton motion in the presence of magnetic field.
Linear Ion Beam Applications for Roll-to-Roll Metal Thin Film Coatings on PET Substrates
Lee, Seunghun ; Kim, Do-Geun ;
Applied Science and Convergence Technology, volume 24, issue 5, 2015, Pages 162~166
DOI : 10.5757/ASCT.2015.24.5.162
Linear ion beams have been introduced for the ion beam treatments of flexible substrates in roll-to-roll web coating systems. Anode layer linear ion sources (300 mm width) were used to make the linear ion beams. Oxygen ion beams having an ion energy from 200 eV to 800 eV used for the adhesion improvement of Cu thin films on PET substrates. The Cu thin films deposited by a conventional magnetron sputtering on the oxygen ion beam treated PET substrates showed Class 5 adhesion defined by ASTM D3359-97 (tape test). Argon ion beams with 1~3 keV used for the ion beam sputtering deposition process, which aims to control the initial layer before the magnetron sputtering deposition. When the discharge power of the linear ion source is 1.2 kW, static deposition rate of Cu and Ni were 7.4 and
Interband Transition and Confinement of Charge Carriers in CdS and CdS/CdSe Quantum Dots
Man, Minh Tan ; Lee, Hong Seok ;
Applied Science and Convergence Technology, volume 24, issue 5, 2015, Pages 167~171
DOI : 10.5757/ASCT.2015.24.5.167
Quantum-confined nanostructures open up additional perspectives in engineering materials with different electronic and optical properties. We have fabricated unique cation-exchanged CdS and CdS/CdSe quantum dots and measured their first four exciton transitions. We demonstrate that the relationship between electronic transitions and charge-carrier distributions is generalized for a broad range of core-shell nanostructures. These nanostructures can be used to further improve the performance in the fields of bio-imaging, light-emitting devices, photovoltaics, and quantum computing.
Fabrication of Disordered Subwavelength Structures on Curved Surfaces by Using a Thermal Dewetting Process
Lee, Jong Heon ; Song, Young Min ;
Applied Science and Convergence Technology, volume 24, issue 5, 2015, Pages 172~177
DOI : 10.5757/ASCT.2015.24.5.172
We present disordered moth eye structures on curved surfaces fabricated by dry etching of thermally dewetted metal nanoparticles. This lithography-free fabrication allows the formation of subwavelength scale nanostructures on the strongly inclined surfaces such as ball lens as well as on the microlens arrays with low curvature. In particular, we found that the size and average distance of nanostructures are closely related to the inclined angle of the surface. Experimental results on oblique angle deposition of metal thin films followed by thermal dewetting also support these effects.
Vanadium Oxide Microbolometer Using ZnO Sandwich Layer
Han, Myung-Soo ; Kim, Dae Hyeon ; Ko, Hang Ju ; Kim, Heetae ;
Applied Science and Convergence Technology, volume 24, issue 5, 2015, Pages 178~183
DOI : 10.5757/ASCT.2015.24.5.178
Optical, electrical and structural properties of VOx/ZnO/VOx thin film are studied. The VOx/ZnO/VOx multilayer is deposited by using a radio frequency (RF) sputtering system. The VOx/ZnO/VOx thin film shows the high temperature coefficient of resistance (TCR) of
and the low sheet resistance of about 80
at room temperature. The responsivity and detectivity of the bolometer are measured as a function of modulation frequency.
Enhancement of Size Gradient of Imprinted Nanopattern by Plasma Etching under a Nonuniform Magnetic Field
Lim, Jonghwan ; Kim, Soohyun ; Kim, Da Sol ; Jeong, Mira ; Lee, Jae-Jong ; Yun, Wan Soo ;
Applied Science and Convergence Technology, volume 24, issue 5, 2015, Pages 184~189
DOI : 10.5757/ASCT.2015.24.5.184
We report a simple way to enhance the size gradient of an imprinted nanopattern through oxygen plasma etching under a nonuniform magnetic field. A sample substrate was placed next to a magnet, and then a nonuniform magnetic field condition was formed around the sample. Using oxygen plasma etching, a line pattern having an initial width of 273 nm was gradually modified from 248 nm at one end to 182 nm at the other end. Controlling the arrangement of the magnet and sample, we could induce a triangular shape size gradient. We verified that the gradually modified nanopatterns we produced are applicable to continual optical property control, showing a possibility to be utilized for optical components such as gratings and polarizers.
A Reusable Pb
Detecting Aptasensor Employing a Gold Nanorod-DNAzyme Conjugate
Lee, Jayeon ; Ha, Tai Hwan ;
Applied Science and Convergence Technology, volume 24, issue 5, 2015, Pages 190~195
DOI : 10.5757/ASCT.2015.24.5.190
Here, we demonstrated a
detecting aptasensor using
-sensitive DNAzyme-conjugated gold nanorods (GNRs). Fluorescent DNA substrates that were initially quenched by GNRs, are released in response to
ions to give a substantial fluorescence signal. The GNR-tethered DNAzyme is reusable at least three times with a LOD of 50 nM.
Fabrication and Simulation of Fluid Wing Structure for Microfluidic Blood Plasma Separation
Choe, Jeongun ; Park, Jiyun ; Lee, Jihye ; Yeo, Jong-Souk ;
Applied Science and Convergence Technology, volume 24, issue 5, 2015, Pages 196~202
DOI : 10.5757/ASCT.2015.24.5.196
Human blood consists of 55% of plasma and 45% of blood cells such as white blood cell (WBC) and red blood cell (RBC). In plasma, there are many kinds of promising biomarkers, which can be used for the diagnosis of various diseases and biological analysis. For diagnostic tools such as a lab-on-a-chip (LOC), blood plasma separation is a fundamental step for accomplishing a high performance in the detection of a disease. Highly efficient separators can increase the sensitivity and selectivity of biosensors and reduce diagnostic time. In order to achieve a higher yield in blood plasma separation, we propose a novel fluid wing structure that is optimized by COMSOL simulations by varying the fluidic channel width and the angle of the bifurcation. The fluid wing structure is inspired by the inertial particle separator system in helicopters where sand particles are prevented from following the air flow to an engine. The structure is ameliorated in order to satisfy biological and fluidic requirements at the micro scale to achieve high plasma yield and separation efficiency. In this study, we fabricated the fluid wing structure for the efficient microfluidic blood plasma separation. The high plasma yield of 67% is achieved with a channel width of
in the fabricated fluidic chip and the result was not affected by the angle of the bifurcation.