• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
• /
• pp.368-369
• /
• 2006

By means of magnetic pulsed compaction and sintering of weakly aggregated alumina based nanopowders the jet forming nozzle samples for the hydroabrasive cutting were fabricated. The ceramics was obtained from pure alumina, as well as from alumina, doped by $TiO_2$, MgO and AlMg. It was shown that the samples sintered from AlMg doped $Al_2O_3$ powder have the best mechanical properties and structural characteristics: relative density ${\sim}0.97$, channel microhardness. - 18-20 GPa, channel surface roughness ${\sim}0.7\;{\mu}m$, average crystallite size ${\sim}1\;{\mu}m$.

• The Korean Journal of Physiology and Pharmacology
• /
• 제19권1호
• /
• pp.73-79
• /
• 2015

Connexins (Cx) are membrane proteins and monomers for forming gap junction (GJ) channels. Cx46 and Cx50 are also known to function as conductive hemichannels. As part of an ongoing effort to find GJ-specific blocker(s), endocrine disruptors were used to examine their effect on Cx46 hemichannels expressed in Xenopus oocytes. Voltage-dependent gating of Cx46 hemichannels was characterized by slowly activating outward currents and relatively fast inward tail currents. Bisphenol A (BPA, 10 nM) reduced outward currents of Cx46 hemichannels up to ~18% of control, and its effect was reversible (n=5). 4-tert-Octylphenol (OP, $1{\mu}M$) reversibly reduced outward hemichannel currents up to ~28% (n=4). However, overall shapes of Cx46 hemichannel current traces (outward and inward currents) were not changed by these drugs. These results suggest that BPA and OP are likely to occupy the pore of Cx46 hemichannels and thus obstruct the ionic fluxes. This finding provides that BPA and OP are potential candidates for GJ channel blockers.

• 한국생물물리학회:학술대회논문집
• /
• 한국생물물리학회 1997년도 학술발표회
• /
• pp.23-23
• /
• 1997

Tolaasin, a 1.9 kDa peptide forming membrane pores, is produced by Pseudomonas tolaasii and causes a brown blotch disease on cultivated oyster mushroom. During the purification of peptide by a gel permeation chromatography, we have found that fractions of molecular weight ranges between ∼2 to 40 kDa have hemolytic activities and the fractions of higher M.W. showed faster hemolysis.(omitted)

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제1권1호
• /
• pp.40-49
• /
• 2001

We have developed a repeatable process of forming uniform, small-size and high-density self-assembled Si nano-crystals. The Si nano-crystals were fabricated in a conventional LPCVD (low pressure chemical vapor deposition) reactor at $620^{\circ}c$ for 15 sec. The nano-crystals were spherical shaped with about 4.5 nm in diameter and density of $5{\times}l0^{11}/$\textrm{cm}^2$. More uniform dots were fabricated on nitride film than on oxide film. To take advantage of the above-mentioned characteristics of nitride film while keeping the high interface quality between the tunneling dielectrics and the Si substrate, nitride-oxide tunneling dielectrics is proposed in n-channel device. For the first time, the single electron effect at room temperature, which shows a saturation of threshold voltage in a range of gate voltages with a periodicity of ${\Delta}Ｖ_{GS}\;{\approx}\;1.7{\;}V$, corresponding to single and multiple electron storage is reported. The feasibility of p-channel nano-crystal memory with thin oxide in direct tunneling regime is demonstrated. The programming mechanisms of p-channel nano-crystal memory were investigated by charge separation technique. For small gate programming voltage, hole tunneling component from inversion layer is dominant. However, valence band electron tunneling component from the valence band in the nano-crystal becomes dominant for large gate voltage. Finally, the comparison of retention between programmed holes and electrons shows that holes have longer retention time.

• 한국해양공학회지
• /
• 제24권5호
• /
• pp.8-15
• /
• 2010

The flow around a two-dimensional, rectangular cylinder that is freely falling in a channel was simulated using the immersed boundary method with direct forcing to determine the interactions between the fluid and the structure. The results of the present study were in good agreement with previous experimental results. Regardless of the H/L ratio (where H and L are the height and width of the rectangular cylinder, respectively), the flow structures had essentially the same pattern as the two symmetrical circulations that form about the horizontal center of the cylinder, with those centers located at each lateral position near the wake. When the cylinder approaches very close to the bottom, a jet-like flow appeared between the bottom of the rectangular cylinder and the channel. When the jet-like flow goes through the channel, surrounding fluids are sucked into this jet, forming the secondary vortices.

• 한국전산유체공학회지
• /
• 제11권4호
• /
• pp.75-80
• /
• 2006

Navier-Stokes simulation of the flow in a micro viscous pump is carried out. The micro viscous pump consists of a rotating circular rotor placed in a two dimensional channel. All simulation is carried out by using a finite volume approach, at the Reynolds number of 0.5, to study the performance of the micro viscous pump. Length of channel of the pump is varied to simulate the effects of the pumping load. Numerical solutions show that the net flow of the pump is realized by two counter rotating vortices formed on both sides of the rotor. The volume flow rate of the pump is decreased as length of the channel is increased, while the static pressure difference across the rotor is increased. The static pressure difference across the rotor is observed to be inversely proportional to the volume flow rate as inertia effects are negligibly small. The efficiency of the pump is found to reach a maximum when two counter rotating vortices on both sides of the rotor becomes to merge forming an outer enveloping vortex.

• 한국통신학회논문지
• /
• 제40권4호
• /
• pp.646-652
• /
• 2015

본 논문은 다중 사용자 MIMO 시스템에서 사용자 선택을 위해 필요한 precoding matrix index (PMI)/channel quality indication (CQI)의 보고 방식에 따른 성능을 분석한다. 이러한 분석을 통해 셀 내의 단말의 수, 선택되는 사용자의 수, 그리고 코드북(codebook)의 크기가 Best Companion Grouping (BCG)방식 스케쥴링의 성능에 복잡하게 영향을 미치는 것을 확인한다. 이에 따라 셀 내의 사용자 수와 코드북의 크기에 따라 동시에 스케쥴링 되는 사용자들의 그룹이 형성될 수 있는 확률이 달라지는 것을 확인할 수 있으며, 피드백 오버헤드가 주어졌을 때 이에 따라 피드백하는 PMI의 수와 사용하는 코드북의 크기를 적응적으로 선택함으로써 시스템의 평균 수율 성능을 최적화할 수 있음을 보였다.

• Fisheries and Aquatic Sciences
• /
• 제15권1호
• /
• pp.9-14
• /
• 2012

The objectives of this research were to improve the film-forming properties of Channel Catfish Ictalurus punctatus skin gelatin (CSG) by cross-linking with transglutaminase (TG), determine and optimize the TG reaction time, and characterize the mechanical and barrier properties of CSG edible film. Cross-linking of CSG was performed by TG for 0, 10, 20, 30, and 40 min at $50^{\circ}C$, and the reaction was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The color and mechanical and barrier properties of edible films fabricated with CSG cross-linked with TG were characterized. Gelatin yields from the extraction ranged from 18.2% to 23.3%. SDS-PAGE exhibited dark bands at 120 and 250 kDa, indicating successful TG-mediated cross-linking. The color of CSG film was not affected by TG cross-linking. The tensile strength of CSG films cross-linked with TG decreased from 42.59 to 21.73 MPa and the percent elongation increased from 42.92% to 76.96% as reaction times increased from 0 to 40 min. There was no significant difference in water vapor permeability of CSG films.

• 한국석유지질학회지
• /
• 제2권2호
• /
• pp.71-81
• /
• 1994

선상지 삼각주는 흔히 깊은 분지로 전진하여 급경사의 전면층을 형성한다. 현생의 급경사 선상지-삼각주는 사태흔적, 츄트/협곡, 스웨일(swale), 로브(lobe), 스플레이(splay). 및 암설낙하(debris fall) 등의 표층 지형에 의해 특징지워진다. 이들은 강하구에서 발생하는 퇴적물 붕괴나 중력류에 의해 생성된다. 고기의 선상지-삼각주 퇴적상은 경사가 급한 전면층과 비교적 경사가 완만한 기저층 및 전삼각주(prodelta)층을 구성한다. 이는 다시 판상 또는 쐐기 모양의 역암 및 사암, 사태 충진층, 츄트/협곡 충진층, 판상층, 열편층, 사태층 등으로 구성된다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 춘계합동학술대회 논문집
• /
• pp.172-175
• /
• 2002

The technique of induced discharge by a pulsed CO2 laser is being applied to control electrical discharge path, material processing, triggered lightning for protecting the power equipments. In this paper, we have investigated about the characteristics of the induced discharge at atmospheric conditions by using a plasma channel, which is produced when a pulsed CO2 laser radiation is focused by a focusing mirror as a trigger source. A plasma channel produced by laser radiation has an effect on decreasing the threshold voltage and inducing the discharge in both needle electrodes. We have confirmed a delay time between a produced plasma channel and an electrical discharge after laser radiation. We provided the decreased voltage lower than the natural discharge voltage between electrode type of needles and was induced the discharge by forming a plasma channel between them. In this research we could understand the time delay of induced discharge by laser radiation, and the characteristics of the discharge cause by the decrease in the threshold voltage, and the polarity effect by changes of plasma channel positions between two electrodes.