• Animal cells and systems
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• 제11권2호
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• pp.169-173
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• 2007

Hyperpolarization-activated nonselective cation channels (HCNs) play a pivotal role in producing rhythmic electrical activity in the heart and the nerve cells. In our previous experiments, voltage-dependent $Cd^{2+}$ access to one of the substituted cysteines in S6, T464C, supports the existence of an intracellular voltage-dependent activation gate. Direct binding of intracellular cAMP to HCN channels also modulates gating. Here we attempted to locate the cAMP-modulated structure that can modify the gating of HCN channels. SpHCN channels, a sea urchin homologue of the HCN family, became inactivated rapidly and intracellular cAMP removed this inactivation, resulting in about eight-fold increase of steady-state current level. T464C was probed with $Cd^{2+}$ applied to the intracellular side of the channel. We found that access of $Cd^{2+}$ to T464C was strongly gated by cAMP as well as voltage. Release of bound $Cd^{2+}$ by DMPS was also gated in a cAMP-dependent manner. Our results suggest the existence of an intracellular cAMP-modulated gate in the lower S6 region of spHCN channels.

• Journal of Power Electronics
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• 제16권2호
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• pp.786-797
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• 2016

This paper describes the design and development of a novel semiconductor-based solid-state switch for damped oscillating voltage test system. The proposed switch is configured as two identical series-connected switch stacks, each of which comprising 10 series-connected IGBT function units. Each unit consists of one IGBT, a gate driver, and an auxiliary voltage sharing circuit. A single switch stack can block 20 kV-rated high voltage, and two stacks in series are proven applicable to 30 kV-rated high voltage. The turn-on speed of the switch is approximately 250 ns. A flyback topology-based power supply system with a front-end power factor correction is built for the drive circuit by loosely inductively coupling each unit with a ferrite core to the primary side of a power generator to obtain the advantages of galvanic isolation and compact size. After the simulation, measurement, and estimation of the parasitic effect on the gate driver, a prototype is assembled and tested under different operating regimes. Experimental results are presented to demonstrate the performance of the developed prototype.

• Journal of Information Display
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• 제12권1호
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• pp.47-50
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• 2011

Highly stable amorphous indium.gallium.zinc-oxide (a-IGZO) thin-film transistors (TFTs) were fabricated with an etchstopper and via-hole structure. The TFTs exhibited 40 $cm^2$/V s field-effect mobility and a 0.21 V/dec gate voltage swing. Gate-bias stress induced a negligible threshold voltage shift (${\Delta}V_{th}$) at room temperature. The excellent stability is attribute to the via-hole and etch-stopper structure, in which, the source/drain metal contacts the active a-IGZO layer through two via holes (one on each side), resulting in minimized damage to the a-IGZO layer during the plasma etching of the source/drain metal. The comparison of the effects of the DC and AC stress on the performance of the TFTs at $60^{\circ}C$ showed that there was a smaller ${\Delta}V_{th}$ in the AC stress compared with the DC stress for the same effective stress time, indicating that the trappin of the carriers at the active layer-gate insulator interface was the dominant degradation mechanism.

• Design & Manufacturing
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• 제10권2호
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• pp.50-54
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• 2016

In the semiconductor industry the final products were checked for several environments before sell the products. The burning test of memory and chip was implemented in reliability for all of parts. The memory and chip were developed to high density memory and high performance chip, so circuit design was also high integrated and the test bed was needed to be thin and fine pitch socket. LGA(Land Grid Array) IC socket with thin wall thickness was designed to satisfy this requirement. The LGA IC socket plastic part was manufacture by injection molding process, it was needed accuracy, stiffness and suit resin with high flowability. In this study, injection molding process analysis was executed for 2 and 4 cavities moldings with runner, gate and sprue. The warpage analysis was also implemented for further gate removal process. Through the analyses the total deformations of the moldings were predicted within maximum 0.05mm deformation. Finally in consideration of these results, 2 and 4 cavities molds were designed and made and tested in injection molding process.

• 교육녹색환경연구
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• 제10권1호
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• pp.53-63
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• 2011

The purpose of this study is to suggest a scheme to provide children safer and more comfortable walking circumstances by survey current walking circumstances of schoolzone ways. A scheme suggested in this study was based on the analysis of survey to elementary school in 3 Newtowns(Dongtan, Dongbaek and Gumdan City) and actually surveyed data on school zone, the scheme can be summed up as follows; First, to avoid pedestrian roads being interrupted and to expend waiting space near schoolzone ways, several measures are needed including fixing roads and building additional gateway. Second, pedestrian crossings in front of school gate should be located at least 30m away from the left side of the gate. Third, to secure pedestrians' safety in school zone ways should be planed and established more security concepts und facilities.

• ETRI Journal
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• 제38권4호
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• pp.645-653
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• 2016

This paper demonstrates the performance of a metal-substrate power module with multiple fabricated chips for a high current electrical application, and evaluates the proposed module using a 1.5-kW sinusoidal brushless direct current (BLDC) motor. Specifically, the power module has a hybrid structure employing a single-layer heat-sink extensible metal board (Al board). A fabricated motor driver IC and trench gate DMOSFET (TDMOSFET) are implemented on the Al board, and the proper heat-sink size was designed under the operating conditions. The fabricated motor driver IC mainly operates as a speed controller under various load conditions, and as a multi-phase gate driver using an N-ch silicon MOSFET high-side drive scheme. A fabricated power TDMOSFET is also included in the fabricated power module for three-phase inverter operation. Using this proposed module, a BLDC motor is operated and evaluated under various pulse load tests, and our module is compared with a commercial MOSFET module in terms of the system efficiency and input current.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권4호
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• pp.473-481
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• 2012

For a mesa-isolated small geometry SOI MOSFET, the potentials in the silicon film, front, back, and side-wall oxide layers can be derived three-dimensionally. Using Taylor's series expansions of the trigonometric functions, the derived potentials are written in terms of the natural length that can be determined by using the derived formula. From the derived 3-D potentials, the minimum values of the front and the back surface potentials are derived and used to obtain the closed-form expressions for the front and back gate threshold voltages as functions of various device parameters and applied bias voltages. Obtained results can be found to explain the drain-induced threshold voltage roll-off and the narrow width effect of a fully depleted small geometry SOI MOSFET in a unified manner.

• Journal of Information Display
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• 제7권1호
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• pp.1-6
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• 2006

A 10" carbon nanotube field emission display device was fabricated with a novel structure with a hopping electron spacer (HES) by screen printing technique. HES plays a role of preventing the broadening of electron beams emitted from carbon nanotubes without electrical discharge during operation. The structure of the novel tetrode is composed of carbon nanotube emitters on a cathode electrode, a gate electrode, an extracting electrode coated on the top side of a HES, and an anode. HES contains funnel-shaped holes of which the inner surfaces are coated with MgO. Electrons extracted through the gate are collected inside the funnel-shaped holes. They hop along the hole surface to the top extracting electrode. In this study the effects of the addition of HES on emission characteristics of field emission display were investigated. An active ozone treatment for the complete removal of residues of organic binders in the emitter devices was applied to the field emission display panel as a post-treatment.

• 교육녹색환경연구
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• 제8권2호
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• pp.12-21
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• 2009

The purpose of this study is to suggest a scheme to provide children safer and more comfortable walking circumstances by survey current walking circumstances of school zone ways. First, to avoid pedestrian roads being interrupted and to expand waiting space near school zone ways, several measures are needed including fixing roads, using schools' unemployed spaces and building additional gateway. Second, pedestrian crossings in front of school gate should be located at least 23.16m away from the left side of the gate. Third, on narrow path which cross main streets, the interval of pedestrian signal should be extended as against of the moment. And traffic calming facilities should be built on accurate position. Fourth, to secure pedestrians' safety and field of view, trees lining streets and any obstacles located within 10m from bus stop sign should be removed. Finally, education system about school zone ways should be improved to help children get used to more complicated roads' conditions.

• 반도체디스플레이기술학회지
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• 제5권1호
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• pp.17-20
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• 2006

This paper presents of a new type of memory cell that could potentially replace both DRAM and flash memory. The proposed device cell operates by sensing the state of about 1,000 electrons trapped between unique insulating barriers in the channel region of the upper transistor. These electrons are controlled by a side gate on the transistor, and their state in turn controls the gate of the larger transistor, providing signal gain within the memory cell. It becomes faster and more reliable memory with lower operation voltage. Moreover, the use of a multiple tunnel junction (MTJ) fur the vertical transistor can significantly improve the data retention and operation speed.