• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.5
• /
• pp.122-130
• /
• 1996

In this study, machinability of some aluminum-magnesium alloy are experimentally investigated using polycrystalline diamond tool with turning, and evaluated some independent cutting variables affected micrometal cutting characteristics as cutting force, specific cutting resistance, shear angles. To know the effect of cutting parameters of single point diamond machining, experiments were performed to measure cutting forces for high speed turning of aluminum alloy 6061-T6, SM45C and FC20 with poly- crystalline diamond and coated cemented carbide tool. Independent cutting variables were changed to a variety of cutting speed, feed rate, rake angles, material properties of workpiece and tool. Futhermore. Some useful informations are obtained in this study can guide micro metal cutting of aluminum alloy with diamond tool.

• Clean Technology
• /
• v.29 no.1
• /
• pp.71-75
• /
• 2023

In general, the presence of non-selective intercrystalline (grain boundary) defects in polycrystalline metal-organic framework (MOF) or zeolite membranes, which are known to be ca. 1 nm in size, causes lower membrane performance (selectivity) than the intrinsically expected. In this study we show that applying a thin polymeric coating of polydimethylsiloxane (PDMS) on a polycrystalline MOF membrane is effective to cap the non-selective intercrystalline defects and therefore improve membrane performance. To demonstrate the concept, first, polycrystalline UiO-66, one of Zr-based MOFs, membranes were prepared by an in-situ solvothermal growth. By controlling membrane growth condition with respect to growth temperature, we were able to obtain polycrystalline UiO-66 membranes at 150 ℃ with intercrystalline defects of which the quantity is not significant, so it can be plugged by the suggested PDMS deposition. Second, their performances were compared before and after the PDMS deposition. As expected, the PDMS deposition ended up with a noticeable increase in CO₂/N₂ ideal selectivity from 6 to 14, indicating successful intercrystalline defect plugging. However, the enhancement in CO₂/N₂ selectivity was accompanied by a significant reduction in CO₂ permeance from 5700 to 33 GPU because the PDMS deposition not only plugs defects but also forms a continuous coating on membrane surface, adding an additional transport resistance.

• Proceedings of the IEEK Conference
• /
• 2000.06b
• /
• pp.322-325
• /
• 2000

N-channel poly-Si TFT, Processed by Solid Phase Crystalline(SPC) on a glass substrate, has been investigated by measuring its electrical properties before and after electrical stressing. It is observed that the threshold voltage shift due to electrical stress varies with various stress conditions. Threshold voltages measured in 1.5$\mu\textrm{m}$ and 3$\mu\textrm{m}$ poly-Si TFTs are 3.3V, 3.V respectively. With the threshold voltage shia the degradation of transconductance(G$\_$m/) and subthreshold swing(S) is also observed.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.129-134
• /
• 2004

The development of fabrication processes of polycrystalline-silicon-thin-film transistors (poly-Si TFTs) at low temperatures is reviewed. Rapid crystallization through laser-induced melt-regrowth has an advantage of formation of crystalline silicon films at a low thermal budget. Solid phase crystallization techniques have also been improved for low temperature processing. Passivation of $SiO_2$/Si interface and grain boundaries is important to achieve high carrier transport properties. Oxygen plasma and $H_2O$ vapor heat treatments are proposed for effective reduction of the density of defect states. TFTs with high performance is reported.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.19 no.5
• /
• pp.38-42
• /
• 1982

N+-P/P+solar cells were fabricated by using the polycrystalline silline wafer with the resistivity of 3-6 ohm-cm. minority carrier lifetimes, measured by Nd: YAG laser, were from 100ns up to 150ns. Conversion efficiency measured under AM 1 irradiation, were about 4%.

• Journal of the Korean Ceramic Society
• /
• v.25 no.5
• /
• pp.425-430
• /
• 1988

In this study, aluminum sec-butoxide, aluminum iso-propoxide were mixed with alcohol such as, secbutanol, iso-propanol. And then Acetyl Acetone, water were added to make Acetyl bond and OH bond. After that, Polymeric alumina sol was synthesized from catalysis reaction with strong acid typically HCl. These alumina soil was dried at 8$0^{\circ}C$~9$0^{\circ}C$ to have a optmum viscosty for spinning, spinned at spinner, and then sintered to make polycrystalline alumina fiber.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08b
• /
• pp.1266-1269
• /
• 2007

Polycrystalline silicon (poly-Si) films were prepared directly on plastic substrates at a low (< $200^{\circ}C$) by using Catalytic Chemical Vapor Deposition (Cat-CVD) technique without subsequent annealing steps. Surface roughness of the poly-Si layer and the density of the gate dielectric layer were found to be influential to the TFT performance.

• Journal of Information Display
• /
• v.11 no.1
• /
• pp.21-23
• /
• 2010

A new level shifter using low-temperature polycrystalline silicon (poly-Si) thin-film transistors (TFTs) for low-power applications is proposed. The proposed level shifter uses a capacitive-coupling effect and can reduce the power consumption owing to its no-short-circuit current. Its power saving over the conventional level shifter is 72% for a 3.3 V input and a 10 V output.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.715-717
• /
• 2006

$NiCl_2$ vapor was introduced into conventional furnace to conduct vapor-induced crystallization (VIC) process. We made the metal chloride atmosphere by sublimating the $NiCl_2$ compound. The $NiCl_2$ atmosphere enhanced the crystallization of amorphous silicon thin films. As the result, polycrystalline Si film with large grain size and low metal contamination has been obtained.

• Transactions of Materials Processing
• /
• v.5 no.4
• /
• pp.297-304
• /
• 1996

A process model is formulated considering the effect of crystallographic texture developed in forming process. The deformation induced plastic anisotropy can be predicted by capturing the evolution of texture during large deformation in the polycrystalline aggregate. The anisotropic stiffness matrix for the aggregate is derived and implemented in Eulerian finite element code using a Consistent Penalty method. As an application the evolution of texture in rolling drawing and extrusion processes are simulated. The numerical results show good agreements with report-ed experimental textures.