• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2007.11a
• /
• pp.125-127
• /
• 2007

MoN 코팅막은 Ar과 $N_2$가 섞인 가스 상태 안에서 몰리브덴(Mo) 타겟을 사용해서 아크 이온 플레이팅법을 사용하여 stainless steel 표면 위에 증착을 시켰다. MoN 코팅막의 미세 결정 구조의 특징은 X-선 회절 분석(X-ray Diffractormeter, Phillips co. X'pert)과 XPS를 사용해서 측정하였다. MoN 코팅막은 순수 Mo 코팅막의 13GPa 보다 높은 25 GPa의 미세경도값을 나타냈으며, 또한 Mo 코팅막에 N의 함량이 증가할수록 마찰계수가 낮아지는 것을 알 수 있었다. 이번 연구에서는 MoN 코팅막에서 질소 함량을 변화 시켜 MoN 코팅막의 미세구조와 그 특성에 대하여 연구하였다.

• Korean Journal of Materials Research
• /
• v.15 no.11
• /
• pp.730-734
• /
• 2005

Cr-Al-Si-N coatings were deposited on WC-Co substrates by a hybrid coating system of arc ion plating and DC magnet :on sputtering technique in $N_2/Ar$ mixture. The Cr-tll-Si-N coatings were synthesized with different Si contents. Their microstructure and mechanical properties were systematically investigated. The average size of crystallites largely decreases with the increase of Si content compared with Cr-Al-N. The microhardness of Cr-Al-Si-N coatings largely increases from 24 to 55 GPa. The enhanced hardness is believed to originate from the microstructural change by the fine composite microstructure of Cr-Al-N coatings with Si addition. The average friction coefficient of Cr-Al-Si-N coatings decreases from 0.84 to 0.45 with increasing Si content up to $16\;at.\%$.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.04a
• /
• pp.173-175
• /
• 2003

At the low temperature of $950^{\circ}C$ the $\mu\textrm{m}$-sized whisker growth during the catalytic CVD of pyrolytic carbon from methane with $H_2$- and Ar-gas on quartz substrate with NiO powder was found in this work. In the preliminary study it was observed from pure methane pyrolysis without catalyst at the high temperature $1500~1700^{\circ}C$. If the growth whisker should be stopped at initial stage, about 20 min. of the methane pyrolysis, it would be nanosized whisker growth. The screw growth mechanism and unique mechanical properties of whisker for composites were also recognized. If the pyrolysis would be continued, we could found also spiral growth of whistlers with diameter of about 1, 5 mm. The large length of whisker was about 10 cm in 20 minute.

• Proceedings of the KWS Conference
• /
• 2002.10a
• /
• pp.620-625
• /
• 2002

Considering the fuel consumption of car, a light structure of aluminum alloys is desired for car body nowadays. However, fusion welding of aluminum alloys has some problems of reduction of joint efficiency, porosity formation and hot cracking. ill the present work, investigation to improve the joint performance of laser welded joint has been carried out by addition of Cu, Ni, and Zr to A6N01 alloy welds. Aluminum alloy plate of 2.0mm in thickness with filler metal bar was welded by twin beam Nd:YAG laser facility (total power:5kW). The filler metals were prepared by changing the chemical compositions for adding the elements into the weld metal. Thirteen filler metal bars were prepared and pre-placed into the base metal before welding. Ar gas shielding with a flow rate of 10 l/min was used. The defocusing distance is kept at 0 mm. At travel speeds of 3 to 9 m/min and at laser power of 5kW (front beam 2kW rear beam 3kW), full penetration welds were obtained, whereas at travel speeds of 12 to 18 m/min and same power, partial penetration was observed. The joint efficiency of laser-welded joint was improved by the addition of Cu, Ni, and Zr due to the solid solution hardening, grain refining and precipitation hardening. The type of hardening has been further considered by metallurgical examination.

• Economic and Environmental Geology
• /
• v.29 no.2
• /
• pp.119-127
• /
• 1996

Electrum-sulfide minerals of the Namsan Au-Ag mine were deposited in two stages of quartz and calcite veins that fill fault planes in Mesozoic granitic rocks (230~155 Ma). The K/Ar radiometric dating of hydrothermal sericite indicates that mineralization is early Cretaceous age ($127{\pm}3.0Ma$). Mineralogic, fluid inclusion and sulfur isotopic data show that ore minerals were deposited at temperatures between $340^{\circ}C$ and $200^{\circ}C$ from fluid with salinities of 3 to 6 equiv. wt % NaCl. Evidence of fluid boiling (and $CO_2$ effervescence) indicates a maximum pressures of 100 bars. The formation temperature and $fs_2$, of Au-mineralization from the Namsan mines are mainly $280{\sim}230^{\circ}C$ and $10^{-11}{\sim}10^{-13}$ atm, respectively. Au deposition was likely a result of boiling caused to chemical change (pH, $f_{O2}$, ${\Sigma}_{H_2S{\cdot}{\cdot}}$) of ore-fluids. Sulfur isotope composition of sulfide minerals (${\delta}^{34}S=5.1$ to 8.2‰) are consistent with ${\delta}^{34}S_{{\Sigma}{H2S}}$ value of +6 to +7‰, suggesting an igneous source of sulfur partially mixed with wall-rock sulfur.

• Journal of the Korean institute of surface engineering
• /
• v.29 no.6
• /
• pp.829-833
• /
• 1996

Superconducting YBaCuO thin films were deposited on MgO (100) single crystal substrate by rf reactive sputtering method. Sputtering target was prepared by mixing the original powders of $Y_2O_3$, $BaCO_3$, and CuO at $830^{\circ}C$, and its composition was $YBa_2Cu_{3.3}O_x$ adding the excess CuO to compensate for the loss of Cu in the deposition process. The sputtering conditions for a high quality of YBCO thin film were: substrate temperature of 13$0^{\circ}C$; gas pressure of 10 mTorr; gas mixture ($O_2$: Ar =10: 90); distance of 2.5 inch; and rf power density of 4.87 W /$\textrm{cm}^2$. The deposition rate was 2.4~2.6 nm/min. From the RBS results, it was found that Cu and Ba contents in thin films decreased with the increase of substrate temperature. The increase of gas pressure resulted in significant deficiency of Ba elements.

• The Korean Journal of Ceramics
• /
• v.6 no.4
• /
• pp.354-358
• /
• 2000

The SnO$_2$film was deposited on a corning glass 1737 substrate by plasma enhanced chemical vapor deposition using a gas mixture of SnCl$_4$, $O_2$, and Ar. The film thickness was measured using $\alpha$-step and was about 9400$\AA$. The conventional X-ray diffractometry and pole figure attachment were used to refine the crystal structure of SnO$_2$ thin film. Six pole figures, (200), (211), (310), (301), (321), and (411), were measured with CoK$_\alpha$ radiation in reflection geometry. The X-ray diffraction data were measured at room temperature using CuK$_\alpha$ radiation with graphite monochromator. The agreement between calculated and observed patterns for the normal direction of SnO$_2$ thin film was not satisfactory due to the severely preferred orientation effect. The Rietveld refinement of heavily textured SnO$_2$ thin film was successfully achieved by adopting the pole density distribution of each reflection obtained from the inverse pole figure as a correction factor for the preferred orientation effect. The R-weighted pattern, R$_wp$, was 15.30%.

• Journal of Powder Materials
• /
• v.21 no.5
• /
• pp.355-359
• /
• 2014

Pt nanopowder-dispersed $SiO_2$ (SOP) films were prepared by RF co-sputtering method using Pt and $SiO_2$ targets in Ar atmosphere. The growth rate and Pt content in the film were controlled by means of manipulating the RF power of Pt target while that of $SiO_2$ was fixed. The roughness of the film was increased with increasing the power of Pt target, which was mainly due to the increment of the size and planar density of Pt nanopowder. It was revealed that SOP film formed at 10, 15, 20 W of Pt power contained 2.3, 2.7, and 3.0 nm of spherical Pt nanopowder, respectively. Electrical conductivity of SOP films was exponentially increased with increasing Pt power as one can expect. Interestingly, conductivity of SOP films from Hall effect measurement was greater than that from DC I-V measurement, which was explained by the significant increase of electron density.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.48 no.2
• /
• pp.169-180
• /
• 2022

Streptococcus sp. is generally known as a strain that produces hyaluronic acid. In this study, we focused on ingredients other than hyaluronic acid among several metabolites produced by Streptococcus sp. during cultivation. The hair experimental sample (HAIRCLE^TM) was prepared with Streptococcus sp. culture filtrate under the condition that hyaluronic acid was not produced and the effect on the hair was identified. Tensile strength of hair was tested with a universal testing machine (UTM). Surface properties of a hair were examined with an atomic force microscope (AFM). Our results suggest that HAIRCLE^TM could prevent damage to a hair such as destroyed-cuticle, increased-faction force, and broken-hair. Furthermore, hair-related experiments confirmed that HAIRCLE^TM could promote the expression of hair growth factors VEGF, HGF, and Wnt10b and mitigate male hair loss by inhibiting androgen receptors and TGF-β2 expression. In addition, it was confirmed that the expression of barrier-related factors (INV, CLDN-1) was increased for oxidative stress, and the COX-2 expression, an inflammatory factor, was inhibited, thereby improving damaged scalp barriers and alleviating induced inflammation.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
• /
• 2006.10a
• /
• pp.68-71
• /
• 2006

Multi-component $ZnO-In_2O_3-SnO_2$ thin films have been prepared by RF magnetron co-sputtering using targets composed of $In_3Sn_4O_{12}$(99.99%) [1] and ZnO(99.99%) at room temperature. $In_3Sn_4O_{12}$ contains less In than commercial ITO, so that it lowers cost. Working pressure was held at 3 mtorr flowing Ar gas 20 sccm and sputtering time was 30 min. RF power ratio [RF1 / (RFI + RF2)] of two guns in sputtering system was varied from 0 to 1. Each RF power was varied $0{\sim}100W$ respectively. The thickness of the films was $350{\sim}650nm$. The composit ion concentrations of the each film were measured with EPMA, AES and XPS. The low resistivity of $1-2\;{\times}\;10^3$ and an average transmittance above 80% in the visible range were attained for the films over a range of ${\delta}\;(0.3\;{\leq}\;{\delta}\;{\leq}\;0.5)$. The films also showed a high chemical stability with time and a good uniformity.