• Korean Journal of Materials Research
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• v.13 no.4
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• pp.205-212
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• 2003

RF sputtering process was applied to produce thin hydroxyapatite［HA, Ca10($PO_4$)$_{6}$ $ (OH)_2$films on Ti-6Al-4V alloy substrates. To make a 101.6 mm dia.${\times}$5 mm HA target, the commercial HA powder was first calcinated for 3h at $200^{\circ}C$. A certain amount of the calcinated HA powder was pressed under a pressure of 20,000 psi by the cold isostatic press(CIP) and the pressed HA target was sintered for 6 h at $1,200^{\circ}C$. The effects of different heat treating conditions on the bonding strength between HA thin films and Ti-6Al-4V alloy substrates were studied. Before deposition, the alloy substrates were annealed for 1 h at $850^{\circ}C$ under $3.0${\times}$10^{-3}$ Xtorr, and after deposition, the hydroxyapatite/Ti-6Al-4V alloy thin films were annealed for 1 h at 400, 600 and $800^{\circ}C$ under the atmosphere, respectively. Experimental results represented that the HA thin films on the annealed substrates had higher hardness than non-heat treated substrates before the deposition.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.52-57
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• 2001

Fatigue crack growth behaviour of Ti-6A-4V alloy is investigated in air and salt solution environment at room temperature and $200^{\circ}C$. Fatigue crack growth rate is blown to be fast for the formation of corrosive product in hot salt environment. For the effect on corrosion fatigue crack growth behaviour of region II. fatigue crack growth rate in atmosphere had a little gap to both case, $200^{\circ}C$ and room temperature. However, it showed very fast tendency in salt corrosive atmosphere, and it was remarkably accelerated in $200^{\circ}C$ temperature salt environment. When $\Delta$K was approximately 30MPa(equation omitted), fatigue crack growth rate had a little difference between at room temperature and at $200^{\circ}C$ high temperature, however in case of salt corrosive environment the room temperature was 3.5 times Inter and $200^{\circ}C$ high temperature for 16 times than air environment respectively.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.4
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• pp.208-212
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• 2004

In this paper, the characteristics of co-sputtered Ru-Zr metal alloy as gate electrode of MOS capacitors have been investigated. The atomic compositions of alloy were varied by using the combinations of relative sputtering power of Ru and .Zr. C-V and I-Vcharacteristics of MOS capacitors were measured to find the effective oxide thickness and work function. The alloy made of about 50% of Ru and 50% of Zr exhibited an adequate work function for nMOS. C-V and I-V measurements after 600 and $700^{\circ}C$ rapid thermal annealing were performed to prove the thermal and chemical stability of the Ru-Zr alloy film. Negligible changes in the accumulated capacitance and work function before and after annealing were observed. Sheet resistance of Ru-Zr alloy was lower than that of poly-silicon. It can be concluded that the Ru-Zr alloy can be a possible substitute for the poly-silicon used as a gate of nMOS.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.737-740
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• 2010

High leakage current and threshold voltage shift(${\Delta}Vth$) are demerits of a-Si:H TFT. These characteristics are influenced by gate insulator and active layer film quality, surface roughness, and process conditions. The purpose of this investigation is to improve off current($I_{off}$) and ${\Delta}V_{th}$ characteristics. Nitrogen-rich deposition condition was applied to gate insulator, and hydrogen-rich deposition condition was applied to active layer to reduce electron trap site and improve film density. $I_{off}$ improved from 1.01 pA to 0.18 pA at $65^{\circ}C$, and ${\Delta}V_{th}$ improved from -1.89 V to 1.22 V.

• KSBB Journal
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• v.20 no.2 s.91
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• pp.106-111
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• 2005

The functional relationship between the number of mole of an i-fatty acid (Si) included in fish oil and the hydrolysis time(t) was expressed as a mathematical model, $S_i=-{\alpha_i}1n(t)+\beta_i$. The average errors of calculated values on the basis of the measured values were distributed in the range of less than $5\%$ for all the 15 fatty aids composing of fish oil. The equation of hydrolysis rate of each fatty acid was deduced as $v_i={\gamma_i}exp(\frac{S_i}{\alpha_i})$ from the above-mentioned $S_i=-{\alpha_i}ln(t)+{\beta_i}$. Therefore the hydrolysis yields of fatty acids were analyzed using the equation of $S_i\;Vs.\;t.$. The 15 fatty acids were categorized into 4groups from the view point of hydrolysis yield. The hydrolysis yields of the first group, including C14:0, C16:0, C16:1, C18:0, C18:1 (n-7) and 1l8:1 (n-9), were higher than $70\%$ at 48 hr of hydrolysis. Those of the second group, C20:1, C22:1, C18:3, C20:4 and C20:5, were distributed from $40\%,\;to\;60\%$, and third group were around $30\%$. The final group containing only C22:6 was very hard to be hydrolyzed and the yield was less than $20\%$ at the same time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.295-299
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• 1996

In order to investigate the relation between the microstructure and the V-I characteristics of HTSC wire, single and 19 filamentary silver-sheathed Bi2223 tapes were fabricated using the powder-in-tube method. Higher J$\_$c/ at 77.3 K(0 T) and 4.2 K(in magnetic field) can be achieved for the 19 filamentary Bi tape, comparing the single filamentary tape. However, the I$\_$c/ distribution of 19 filamentary Bi2223 tape was found to be wider by analyzing the curve obtained from 2nd differential of V-I data. This was considered to be resulted from worse uniformity of oxide filament due to severe cold working.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.45-49
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• 2001

We have investigated physical and electrical properties of the Hf $O_2$/HfS $i_{x}$/ $O_{y}$ thin film for alternative gate dielectrics in the metal-oxide-semiconductor device. The oxidation of Hf deposited directly on the Si substrate results in the H $f_{x}$/ $O_{y}$ interfacial layer and the high-k Hf $O_2$film simultaneously. Interestingly, the post-oxidation N2 annealing of the H102/H1Si70y thin films reduces(increases) the thickness of an amorphous HfS $i_{x}$/ $O_{y}$ layer(Hf $O_2$ layer). This phenomenon causes the increase of the effective dielectric constant, while maintaining the excellent interfacial properties. The hysteresis window in C-V curves and the midgap interface state density( $D_{itm}$) of Hf $O_2$/HfS $i_{x}$/ $O_{y}$ thin films less than 10 mV and ~3$\times$10$^{11}$ c $m^{-2}$ -eV without post-metallization annealing, respectively. The leakage current was also low (1$\times$10-s A/c $m^2$ at $V_{g}$ = +2 V). It is believed that these excellent results were obtained due to existence of the amorphous HfS $i_{x}$/ $O_{y}$ buffer layer. We also investigated the charge trapping characteristics using Fowler-Nordheim electron injection: We found that the degradation of Hf $O_2$/HfS $i_{x}$/ $O_{y}$ gate oxides is more severe when electrons were injected from the gate electrode.e electrode.e.e electrode.e.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.166-168
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• 2020

MPEG 비디오 그룹은 MPEG-I 표준의 일부로 포인트 클라우드(Point Cloud) 압축을 위한 비디오 기반 포인트 클라우드 부호화(V-PCC)와 몰입형(immersive) 비디오 압축을 위한 MPEG Immersive Video(MIV) 표준을 개발하고 있다. 최근에는 포인트 클라우드 및 몰입형 비디오와 같은 체적형(volumetric) 비디오를 모두 압축할 수 있도록 V-PCC 와 MIV 를 통합한 V3C(Visual Volumetric Video-based Coding) 표준화를 진행하고 있다. 본 논문에서는 V3C 코덱을 사용한 3DoF+(3 Degree of Freedom plus) 비디오 부호화 방안을 분석한다. 또한 V3C 코덱의 2D 코덱으로 기존 HEVC 대신 VVC 를 사용할 경우의 부호화 성능 향상을 분석한다.

• Transactions on Electrical and Electronic Materials
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• v.8 no.4
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• pp.170-173
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• 2007

Organic field-effect transistors (OFETs) are of interest for use in widely area electronic applications. We fabricated the organic field-effect transistor based a copper phthalocyanine (CuPc) as an active layer on the silicon substrate. The CuPc FET device was made a topcontact type and the substrate temperature was room temperature and $150^{\circ}C$. The CuPc thickness was 40 nm, and the channel length was $50{\mu}m$, channel width was 3 mm. We observed the typical current-voltage (I-V) characteristics and capacitance-voltage (C-V) in CuPc FET and we calculated the effective mobility with each device. Also, we observed the AFM images with different substrate temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.160-160
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• 2007

금속 게이트 전극으로 활용하기 위해서 TiN 박막을 D.C. Magnetron reactive sputtering 방식으로 질소가스와 아르곤 가스 혼합가스를 이용하여 증착하여 MOSCAP을 제작하였다. 박막내의 질소의 조성은 혼합가스내의 질소가스의 분압을 변화시킴으로써 조절하였고, XPS를 이용하여 조성을 분석하였다. 또한 질소농도에 따른 전기적 특성의 분석은 I-V, C-V 측정을 통해 시험하였고 XRD를 이용하여 결정상 분석을 시행하였다. 박막내의 질소농도와 전기적 비저항은 질소분압이 높아짐에 따라 증가하였고, 박막의 workfunction 또한 질소농도의 변화에 따라 변화함을 알 수 있었다.