• Current Optics and Photonics
• /
• 제5권1호
• /
• pp.23-31
• /
• 2021

We propose a wheel screen type Lamina 3D display, which realizes a 3D image that can satisfy the accommodation cue by projecting volumetric images encoded by varying polarization states to a multilayered screen. The proposed system is composed of two parts: an encoding part that converts depth information to states of polarization and a decoding part that projects depth images to the corresponded diffusing layer. Though the basic principle of Lamina displays has already been verified by previous studies, those schemes suffered from a bottleneck of inferior resolution of the 3D image due to the blurring on the surfaces of diffusing layers in the stacked volume. In this paper, we propose a new structure to implement the decoding part by adopting a form of the wheel screen. Experimental verification is also provided to support the proposed principle.

• E2M - 전기 전자와 첨단 소재
• /
• 제8권5호
• /
• pp.611-618
• /
• 1995

The (Sr$_{1-x}$ .Ca$_{x}$)TiO$_{3}$+0.6[mol%]Nb$_{2}$O$_{5}$ (0.05.leq.x.leq.0.2) ceramics were fabricated to form semiconducting ceramics by sintering at about 1350[.deg. C] in a reducing atmosphere(N$_{2}$ gas). Metal oxides, CuO, was painted on the both surface of the specimens to diffuse to the grain boundary. They were annealed at 1100 [.deg. C] for 2 hours. The 2nd phase formed by thermal diffusing from the surface lead to a very high apparent dielectric constant. According to increase of the frequency as a functional of temperature, all specimens used in this study showed the dielectric relaxation, and the relaxation frequency was above 106 [Hz], it move to low frequency with increasing resistivity of grain. The specimens showed three kinds of conduction mechanisms in the temperature range 25-125 [.deg. C] as the current increased: the region I below 200 [V/cm] shows the ohmic conduction. The region rt between 200 [V/cm] and 2000 [V/cm] can be explained by the Poole-Frenkel emission theory, and the region III above 2000 [V/cm] is dominated by the tunneling effect.fect.

• 한국결정성장학회지
• /
• 제29권2호
• /
• pp.50-53
• /
• 2019

박막 태양전지에 주로 적용되는 다결정 규소층을 AIC(Aluminum Induced Crystallization) 공정을 이용하여 제조하였다. 결정립의 확대를 위하여 selective diffusion barrier 사용하였다. 이 diffusion barrier는 $Al_2O_3$ 막을 사용하였다. 공정시간의 단축을 위하여 열처리는 RTA(Rapid Thermal Annealing) 공정으로 진행하였다. 비정질 실리콘의 결정화는 XRD 측정을 통해 분석했다. 그 결과 $500^{\circ}C$에서 결정화되었으며, 결정 크기는 $15.9{\mu}m$로 계산되었다.

• 한국전기전자재료학회논문지
• /
• 제17권12호
• /
• pp.1356-1361
• /
• 2004

High temperature superconducting coated conductor has a structure of ///. The buffer layer consists of multi-layer, this study reports the deposition method and optimal deposition conditions of YSZ(Yttria-stabilized zirconia) layer which plays a important part in preventing the elements of substrate from diffusing into the superconducting layer. YSZ layer was deposited by DC reactive sputtering technique using water vapor for oxidizing deposited elements on substrate. To investigate optimal thickness of YSZ film, four YSZ/CeO$_2$/Ni samples with different YSZ thickness(130 nm, 260 nm, 390 nm, and 650 nm) were prepared. The SEM image showed that the surface of YSZ layer was getting to be rougher as YSZ layer was getting thicker and the growth mode of YSZ layer was columnar grain growth. After CeO$_2$ layer was deposited with the same thickness of 18.3 nm on each four samples, YBCO layer was deposited by PLD method with the thickness of 300 nm. The critical currents of four samples were 0, 6 A, 7.5 A, and 5 A respectively. This shows that as YSZ layer is getting thicker, YSZ layer plays a good role as a diffusion barrier but the surface of YSZ layer is getting rougher.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 하계학술대회 논문집
• /
• pp.406-409
• /
• 2001

In this paper, the microstructure and the dielectric properties of the Sr$_{1-x}$ Ca$_{x}$TiO$_3$(0$\leq$$\chi$$\leq$0.2) -based grain boundary layer ceramics were investigated. The specimens were sintered from 142$0^{\circ}C$ to 152$0^{\circ}C$ for 4hr. in $N_2$ gas. The 2nd phase formed by thermal diffusing from the surface lead to a very high apparent dielectric constant, $\varepsilon$$_{r}$>50000. The structural properties of the specimens were studied by X-ray diffraction and SEM, EDX. All specimens exhibited cubic structure. Increasing content of Ca, the peak intensity were decreased.ed.d.

• 한국전기전자재료학회논문지
• /
• 제17권2호
• /
• pp.150-155
• /
• 2004

This study attempts to form a TiN barrier layer against Cu diffusion by the easier and more convenient method. In this new approach, Ti was sputter-deposited, and nitrided by heat-treating in the NH$_3$ambient. Sheet resistance of as-deposited Ti was 20 Ω/$\square$, but increased to 195 Ω/$\square$ after the heat-treatment at 30$0^{\circ}C$, and lowered to 120 Ω/$\square$ after the heat-treatment at 50$0^{\circ}C$, and $600^{\circ}C$. AES results for these thin films confirmed that the atomic ratio of Ti and N was close to 1:1 at or above 40$0^{\circ}C$ heat-treatment. However, it was also found that excessive oxygen was contained in the TiN layer. To examine the barrier property against Cu diffusion, 100nm Cu was deposited on the TiN layer and then annealed at 40$0^{\circ}C$ for 40 min.. Cu remained at the surface without diffusing into the Si layer.

• 한국재료학회지
• /
• 제17권3호
• /
• pp.179-183
• /
• 2007

A plate heat exchanger (PHE) normally uses vacuum brazing technology for connecting plates and fins. However, the reliability of high temperature brazing, especially with nickel-based filler metals containing boron the formation of brittle intermetallic compounds (IMCs) in brazed joints is of major concern. since they considerably degrade the mechanical properties. This research was examined the vacuum brazing of commercially SUS304 stainless steel with BNi-2 (Ni-Cr-B-Si) filler metal, and discussed to determine the influence of brazing temperatures on the microstructure and mechanical strength of brazed joints. In the metallographic analysis it is observed that considerable large area of Cr-B intermetallic compound phases at the brazing layer and the brazing tensile strength is related to removal of this brittle phase greatly. The mechanical properties of brazing layer could be stabilized through increasing the brazing temperature over $100^{\circ}C$ more than melting temperature of filler metals, and diffusing enough the brittle intermetallic compound formed in the brazing layer to the base metal.

• 전기의세계
• /
• 제27권4호
• /
• pp.45-51
• /
• 1978

A new method of realizing the field effect transistor with a sub-.mu. channel width is described. The sub-.mu. channel width is made possible by etching grooves into n$^{+}$ pn$^{[-10]}$ n$^{[-10]}$ structure and using p region at the wall for the channel region of the Metal-Oxide-Semiconductor transistor (MOST), or by diffusing two different types of impurities through the same diffusion mask and using p region at the surface for the channel region of MOST. When the drain voltage is increased at the pn$^{[-10]}$ drainjunction the depletion layer extends into the n$^{[-10]}$ region instead of into p region; this is also the secret of success to realize the sub-.mu. channel width. As the result of the experimental fabrication, a microwave MOST was obtained. The cut-off frequency was calculated to be 15.4 GHz by Linvill's power equation using the measured capacitances and transconductance.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 C
• /
• pp.1384-1386
• /
• 2001

In this paper, the structural and electrical properties of the $Sr_{1-x}Ca_xTiO_3$($0{\leq}x{\leq}0.2$)-based grain boundary layer ceramics were investigated by X-ray, SEM and V-I system. Increasing content of Ca, the average gram size and the lattice constant were decreased. The relative density of all specimens was > 96%. The 2nd phase formed by thermal diffusing from the surface lead to a very excellent electrical properties, that is, ${\varepsilon}_r$ > 50000, tan${\delta}$ < 0.05, $\Delta$C < ${\pm}$ 10%.

• 한국세라믹학회지
• /
• 제35권1호
• /
• pp.55-65
• /
• 1998

Ag-36.8a%Cu-7.4at%Ti 조성의 브레이징 합금을 Si3N4 기판위에 브레이징한 후 브레이징 합금의 산화거동을 대기중 400, 500, 600$^{\circ}C$에서 조사하였다. 브레이징 합금의 구성원소인 Ag는 산화되지 않고 Cu와 Ti가 산화되며, 산화거동은 포물선적 산화법칙을 따랐다. 브레이징 합금의 산화에 따른 활성화에너지는 80kj/ mol 으로서 소량 첨가된 활성원소인 Ti에 의하여 순수한 Cu의 산화시 활성화에너지보다 감소하였다. 산화 초기에 생성되는 외부산화물은 Cu이온의 외부확산에 의해 성장이 지배되는 Cu산화물로 구성되어 있었다. 산화기간이 경과함에 따라 외부산화물층 아래에서 Cu의 농도는 감소되고 Ag의 농도는 증가하는 농도구배가 발생하여, 브레이징 합금의 산화물은 Cu산화물층(CuO)/Ag잉여층/Cu산화물층(Cu2O)/Ag잉여층의 다층구조를 갖았다. 또한, 분위기중의 산소는 Cu산화물 및 Ag잉여층을 통해 브레이징 합금 내부로 확산되어 브레이징 합금내의 Ti와 반응하여 내부산화물 TiO2를 생성하였다.