• Elastomers and Composites
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• 제56권3호
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• pp.113-116
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• 2021

In this study, we report a facile fabrication of multi-walled carbon nanotubes (MWCNTs)-CuO composites synthesized by a microwave method using MWCNTs and copper oxide (CuO). The number of copper hydrate precursors affect the size and number of CuO domains formed along the MWCNTs in the composites. The domain size is controllable from 239 nm to 348 nm. The composites are characterized by transmission electron microscopy, energy dispersive spectrometry, X-ray diffraction (XRD), Raman spectroscopy, and UV-Vis spectroscopy. The CuO produced in the composites is confirmed to be tenorite with a monoclinic crystal structure through the XRD patterns of (-111), (111) and (-202).

• 한국염색가공학회지
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• 제34권2호
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• pp.77-92
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• 2022

Natural colorants are regarded as substitutes for synthetic colorants in the fields of fiber dyeing, hair dyeing, cosmetic, and food industries. The use of natural colorants has been increased in view of global environment and sustainability. However, scientific approach to the production is required because the supply of natural colorants depends on the climate, soil, and cultivation methods. This brief review contains the advances in science and technology related to natural colorants including characterization, analysis, CIEL^*a^*b^* and Munsell color systems, and future prospects. For the characterization and the analysis of natural colorants, chromatography, some spectroscopic techniques (UV-Vis, FT-IR, NMR), mass spectrometry, and X-ray diffraction are generally used.

• Journal of the Korean Wood Science and Technology
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• 제51권2호
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• pp.69-80
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• 2023

This study conducted scientific analyses on eight objects of wooden lacquerware to understand the manufacturing techniques of wooden lacquerware in the late Joseon Dynasty. The results of lacquer layer analysis with a microscope and scanning electron microscopy-energy dispersive X-ray spectrometry revealed that most samples were composed of 1-3 lacquer layers. Moreover, a red-colored layer was found to be red ocher and cinnabar, and Fourier-transform infrared spectroscopy analysis was carried out to determine the components of the lacquer layer. The detected components were mostly lacquer and partially cashew shell nut liquid.

• Journal of Korean Vacuum Science & Technology
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• 제6권2호
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• pp.92-96
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• 2002

In this paper, we treated the Ni$_3$Al based alloy samples with intense pulsed ion beams (IPIB) at the beam parameters of 250KV acceleration voltage, 100 - 200 A/cm$^2$ current density and 60 u pulse duration. We simulated the thermal-mechanical process near the surface of Ni$_3$Al based alloy with our STEIPIB codes. The surface morphology and the cross-section microstructures of samples were observed with SEM, the composition of the sample surface layer was determined by X-ray Energy Dispersive Spectrometry (XEDS) and the microstructure on the surface was observed by Transmission Electron Microscope (TEM). The results show that heating rate increases with the current density of IPIB and cooling rate reached highest value less than 150 A/cm$^2$. The irradiation of IPIB induced the segregation of Mo and adequate beam parameter can improve anti-oxidation properly of IC6 alloy. Some craters come from extraneous debris and liquid droplets, and some maybe due to the melting of the intersection region of interphase. Increasing the pulse number enlarges average size of craters and decreases number density of craters.

• 한국표면공학회지
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• 제29권6호
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• pp.816-823
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• 1996

Chlorine containing high density plasmas are widely used to etch various materials in the microelectronic device fabrication. In this study, the characteristics of inductively coupled $Cl_2(O_2/N_2$) plasmas and their effects on the formation of silicon etching have been investigated using a Langmuir probe, quadrupole mass spectrometry(QMS), X-ray photoelectron spectroscopy(XPS), and Scanning Electron Microscopy(SEM). The addition of oxygen for chlorine plasmas reduced ion current densities and chlorine radical densities compared to the nitrogen addition by the recombination of oxygen with chlorine. Also, when silicon is etched in $Cl_2/O_2$ plasmas, etch products recombined with oxygen such as $SiCl_xO_y$ emerged. However, when nitrogen is added to chlorine, etch products recombined with nitrogen or Si-N bondings on the etched silicon surface were not found. All the silicon etch characteristics were dependent on the plasma conditions such as ion density, radical density, etc. As a result sub micron vertical silicon trench etch profiles could be effectively formed using optimized etch conditions for $Cl_2/O_2\; and \;Cl_2/N_2$ gas combinations.

• 한국표면공학회지
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• 제32권2호
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• pp.93-99
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• 1999

Surface polymer layer formed on the silicon wafer during the oxide overetching using $C_4F_8$/ helicon wave plasmas and their characteristics were investigated using spectroscopic elipsometry, X-ray photoelectron spectroscopy, and secondary ion mass spectrometry. Overetch percentage and dc-self bias voltage were varied to investigate the effects on the characteristics of the polymers remaining on the overetched silicon surface. The increase of bias voltage from -80 volts to -120 volts increased the C/F ratio and carbon bondings such as C-C, $C-CF_x$/, and C-Si in the polymer while reducing the thickness of the polymer layer. However, the increase of the overetch percentage from 50% to 100% did not change the composition of the polymer layer and the carbon bondings in the polymer layer remained same even though it increased the polymer thickness. The polymer layer formed at the higher dc-self bias voltage was more difficult to be removed by the following various post-etch treatments compared to that formed at the longer overetch percentage.

• 한국전기전자재료학회논문지
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• 제13권3호
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• pp.183-187
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• 2000

In this study the SrBi$_2$Ta$_2$$O_{9}$ (SBT) thin films were etched by using magnetically enhanced inductively coupled Ar/CHF$_3$plasma as function of CHF$_3$/(Ar+CHF$_3$)gas mixing ratio. Maximum etch rate of SBT thin films was 1650 $\AA$/min and the selectivities of SBT to Pt and photoresist(PR) were 1.35 and 0.94 respectively under CHF$_3$/(Ar+CHF$_3$) of 0.1 For study on etching mechanism of SBT thin film X-ray photoelectron spectroscopy (XPS) surface analyses and secondary ion mass spectrometry (SIMS) mass analysis of etched SBT surfaces were performed. Among the elements of SBT thin film. M(Sr, Bi, Ta)-O bonds are broken by Ar ion bombardment and form SrF and TaF$_2$by chemical reaction with F. SrF and TaF$_2$are removed more easily by Ar ion bombardment. Scanning electron microscopy(SEM) was used for the profile examination of etched SBT film and the cross-sectional SEM profile of etched SBT film under CHF$_3$(Ar+CHF$_3$) of 0.1 was about 85$^{\circ}$X>.

• 한국분말재료학회지
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• 제29권1호
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• pp.28-33
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• 2022

Aluminum-based powders have attracted attention as key materials for 3D printing owing to their low density, high specific strength, high corrosion resistance, and formability. This study describes the effects of TiC addition on the microstructure of the A6013 alloy. The alloy powder was successfully prepared by gas atomization and further densified using an extrusion process. We have carried out energy dispersive X-ray spectrometry (EDS) and electron backscatter diffraction (EBSD) using scanning electron microscopy (SEM) in order to investigate the effect of TiC addition on the microstructure and texture evolution of the A6013 alloy. The atomized A6013-xTiC alloy powder is fine and spherical, with an initial powder size distribution of approximately 73 ㎛ which decreases to 12.5, 13.9, 10.8, and 10.0 ㎛ with increments in the amount of TiC.

• Current Photovoltaic Research
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• 제4권1호
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• pp.16-20
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• 2016

$Cu_2ZnSnS_4$ (CZTS) thin films were fabricated by successive electrodeposition of layers of precursor elements followed by sulfurization of an electrodeposited Cu-Zn-Sn precursor. In order to improve quality of the CZTS films, we tried to optimize the deposition condition of absorber layers. In particular, I have conducted optimization experiments by changing the Cu-layer deposition time. The CZTS absorber layers were synthesized by different Cu-layer conditions ranging from 10 to 16 minutes. The sulfurization of Cu/Sn/Zn stacked metallic precursor thin films has been conducted in a graphite box using rapid thermal annealing (RTA). The structural, morphological, compositional, and optical properties of CZTS thin films were investigated using X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and X-ray Flourescenece Spectrometry (XRF). Especially, the CZTS TFSCs exhibits the best power conversion efficiency of 4.62% with $V_{oc}$ of 570 mV, $J_{sc}$ of $18.15mA/cm^2$ and FF of 45%. As the time of deposition of the Cu-layer to increasing, the properties were confirmed to be systematically changed. And we have been discussed in detail below.

• Geomechanics and Engineering
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• 제13권1호
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• pp.141-159
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• 2017

A pick cutter is a rock-cutting tool used in partial-face excavation machines such as roadheaders, and its quality is a key element influencing the excavation performance and efficiency of such machines. In this study, pick cutters with hardfacing deposits applied to a tungsten carbide insert were made with aim of increasing their durability and wear resistance. They were field-tested by being installed in a roadheader and compared with conventional pick cutters under the same excavation conditions for 24 hours. The hardfaced pick cutters showed much smaller weight loss after excavation, and therefore better excavation performance, than the conventional pick cutters. In particular, the damage to and detachment (loss) of tungsten carbide inserts was minimal in the hardfaced pick cutters. A detailed inspection using scanning electron microscope-energy dispersive X-ray spectrometry and three-dimensional X-ray computed tomography scanning revealed no macro- or micro-cracks in the pick cutters. The reason for the absence of cracks may be that the heads of pick cutters are mechanically worn after the tungsten carbide inserts have been worn and damaged. However, scanning revealed the presence of voids between tungsten carbide inserts and pick cutter heads. This discovery of voids indicates the need to improve production processes in order to guarantee a higher quality of pick cutters.