• Journal of Korea Water Resources Association
• /
• v.39 no.12 s.173
• /
• pp.1023-1030
• /
• 2006

The characteristics of the longitudinal velocity in a $180^{\circ}$ constant-radius, recirculating laboratory channel were investigated. Three-dimensional velocity fields were measured using a side-looking ADV. The shortcomings of existing equations for longitudinal velocity are discussed. An eddy viscosity model is adopted in the downstream momentum equation. A mathematical equation was developed to describe the vertical distribution of longitudinal velocity. The comparisons of the longitudinal velocity show generally good agreement. It is found that the curvature change in the curved channel affects the vertical location of maximum velocity and the vertical profile of longitudinal velocity.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.8 no.2
• /
• pp.170-177
• /
• 2008

In the present work a methodology to minimize short channel effects (SCEs) by modulating the effective channel length is proposed to design 25 nm single and double gate-source/drain underlap MOSFETs. The analysis is based on the evaluation of the ratio of effective channel length to natural/ characteristic length. Our results show that for this ratio to be greater than 2, steeper source/drain doping gradients along with wider source/drain roll-off widths will be required for both devices. In order to enhance short channel immunity, the ratio of source/drain roll-off width to lateral straggle should be greater than 2 for a wide range of source/drain doping gradients.

• The Korean Journal of Physiology and Pharmacology
• /
• v.2 no.5
• /
• pp.549-553
• /
• 1998

Using the planar lipid bilayer method, we investigated the effect of d-tubocurarine (dTC) on the extracellular side of large-conductance $Ca^{2+}-activated\;K^+$ channel from rat brain. When the initial open probability (Po) of the channel was relatively high, dTC decreased channel activity in a concentration dependent manner. In contrast, when the initial Po was lower, sub-micro molar dTC increased channel activity by destabilizing the closed states of the channel. Further addition of dTC up to micro molar range decreased channel activity. This dual effect of dTC implicates that there exist at least two different binding sites for dTC.

• The Korean Journal of Physiology and Pharmacology
• /
• v.10 no.2
• /
• pp.71-77
• /
• 2006

The goal of this study was to analyze the effects of genistein, a widely used tyrosine kinase inhibitor, on cloned Shaw-type $K^+$ currents, Kv3.1 which were stably expressed in Chinese hamster ovary (CHO) cells, using the whole-cell configuration of patch-clamp techniques. In whole-cell recordings, genistein at external concentrations from 10 to $100{\mu}M$ accelerated the rate of inactivation of Kv3.1 currents, thereby concentration-dependently reducing the current at the end of depolarizing pulse with an $IC_{50}$ value of $15.71{\pm}0.67{\mu}M$ and a Hill coefficient of $3.28{\pm}0.35$ (n=5). The time constant of activation at a 300 ms depolarizing test pulses from -80 mV to +40 mV was $1.01{\pm}0.04$ ms and $0.90{\pm}0.05$ ms (n=9) under control conditions and in the presence of $20{\mu}M$ genistein, respectively, indicating that the activation kinetics was not significantly modified by genistein. Genistein $(20{\mu}M)$ slowed the deactivation of the tail current elicited upon repolarization to -40 mV, thus inducing a crossover phenomenon. These results suggest that drug unbinding is required before Kv3.1 channels can close. Genistein-induced block was voltage-dependent, increasing in the voltage range $(-20\'mV{\sim}0\'mV)$ for channel opening, suggesting an open channel interaction. Genistein $(20{\mu}M)$ produced use-dependent block of Kv3.1 at a stimulation frequency of 1 Hz. The voltage dependence of steady-state inactivation of Kv3.1 was not changed by $20{\mu}M$ genistein. Our results indicate that genistein blocks directly Kv3.1 currents in concentration-, voltage-, time-dependent manners and the action of genistein on Kv3.1 is independent of tyrosine kinase inhibition.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.3B
• /
• pp.253-262
• /
• 2006

The present paper presents a direct numerical simulation of turbulent flows in a compound open-channel. Mean flows and turbulence structures are provided, and they are compared with the numerical data and measured data available in the literature. The simulated results show that twin vortices are generated near the juncture of the main channel and the floodplain and their maximum magnitude is about 5% of bulk streamwise velocity. At the juncture, the simulated wall shear stress becomes the maximum unlike the experimental data. A quadrant analysis shows that both sweeps and ejections become the main contributor to production of Reynolds shear stresses. A conditional quadrant analysis reveals that the directional tendency of dominant coherent structures determines the production of Reynolds shear stress and the pattern of twin vortices.

• Proceedings of the IEEK Conference
• /
• 2003.07b
• /
• pp.843-846
• /
• 2003

In this paper, we have analyzed algorithm of physical layer, data link layer and MAC layer of Out-Of-Band (OOB) specified in the OpenCabl $e^{TM}$SCTE-55-2 2002$^{[3]}$ and designed architecture of the OOB processor. The OOB processor performs fundamental multiple access control for the OOB channel and extracts session key information from a EMM packet for descrambling MPEG-2 streams. In this paper, we have implemented a prototype board for the DVS167 OOB processor and verified it.t.

• Kyungpook Mathematical Journal
• /
• v.13 no.2
• /
• pp.153-156
• /
• 1973

• Water for future
• /
• v.10 no.2
• /
• pp.61-65
• /
• 1977

• 한국전산유체공학회:학술대회논문집
• /
• 2008.08a
• /
• pp.68.5-69
• /
• 2008

• Proceedings of the Korea Water Resources Association Conference
• /
• 2002.05a
• /
• pp.547-552
• /
• 2002