• The Korean Journal of Physiology
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• v.26 no.2
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• pp.99-111
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• 1992

Permissive action of thyroid hormone at the level of Ca channel and responsible mechanisms underlying thyroid hormone-induced change in myocardial contractile state and $T_3-induced$ arrhythmias were investigated in rabbit ventricular or atrial myocytes using whole cell patch clamp technique. Single cells were isolated by Langendorff perfusion with collagenase. Cardiac myocytes were incubated in $low-Cl^-,$, $high-K^+$ medium containing $1_{\mu}M\;L-triiodothyronine\;(T_3)$ at $4^{\circ}C$ for 2.10 hours. The calcium currrent $(I_{Ca})$ was increased in $T_3$ loaded cells, however, the shape of current voltage curve and reverse potential did not altered. Cyclic AMP, cyclic GMP, isoprenaline and 3-isobutyl-1-methyl-xanthine increased $I_{Ca}$ in euthyroid and hyperthyroid conditions, and acetylcholine blocked the increase of $I_{Ca}\;in\;T_3$ loaded cells. The amplitude of $I_{Ca}$ was much larger after perfusing cGMP than cGMP in both conditions, whereas the degree of increase of $I_{Ca}$ was greater after perfusing cAMP than cGMP in $T_3$ loaded cells. The degree of increase of $I_{Ca}$ after perfusing isoprenaline or IBMX also was greater in $T_3$ loaded cells than in control cells. Background current induced by isoprenaline also increased in $T_3$ loaded cells. The Ca release dependent inward current was increased in amplitude but its activation and inactivation time course was not changed in $T_3$ loaded cells. Activation of Na pump current was not changed in $T_3$ loaded cells. From the above results it is suggested that thyroid hormone induced increase in the contractile state of cardiac myocytes are accompanied by augmented $I_{Ca}$ and the increase of Ca release from sarcoplasmic reticulum and the permissive action of thyroid hormone to catecholamines could induce arrhythmias through the increase of $I_{Ca}$ and background current.

• Archives of Pharmacal Research
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• v.29 no.4
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• pp.310-317
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• 2006

We investigated the effects of trinitrobenzene sulfonic acid (TNBS), an amino-group reagent, on the human ether-a-go-go-related gene (HERG) $K^+$ channels expressed in Xenopus oocytes. TNBS neutralizes the positively charged amino-groups of peptide N-terminal and lysine residues. External application of TNBS at 10 mM for 5 min irreversibly shifted the curves for currents at the end of the pulse and tail currents of HERG to a more negative potential and decreased the maximal amplitude of the $I_{tail}$ curve $(I_{tail,max})$. TNBS had little effect on either the activated current-voltage relationship or the reversal potential of HERG current, indicating that TNBS did not change ion selectivity properties. TNBS shifted the time constant curves of both activation and deactivation of the HERG current to a more hyperpolarized potential; TNBS's effect was greater on channel opening than channel closing. External $H^+$ is known to inhibit HERG current by shifting $V_{1/2}$ to the right and decreasing $I_{tail,max}$. TNBS enhanced the blockade of external $H^+$ by exaggerating the effect of $H^+$ on $I_{tail,max}$, not on $V_{1/2}$. Our data provide evidence for the presence of essential amino-groups that are associated with the normal functioning of the HERG channel and evidence that these groups modify the blocking effect of external $H^+$ on the current.

• Journal of IKEEE
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• v.25 no.2
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• pp.315-321
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• 2021

In this paper, we have developed the multiple channel measurement system for IC Socket Test. The one can test the current-voltage measurements for pitting the several device specification, which analyze the thin current from several ㎂ to 5A with very low resistor mΩ. The increasement of the IC socket channel with lead pitch under 0.25 mm be need to perform several functions, concurrently. The system to perform these functions be designed to integrate several SMU(source measure unit) on board. So, we can reduce the 2 minutes test time per channel point to 40 sec, with daisy chain test method. Using by graphic interface, I-V curve mode and data logging technologies, we can implement the test flow methods and can make economies the time and cost.

• Journal of Power Electronics
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• v.5 no.1
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• pp.55-61
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• 2005

A fuel cell (FC) system includes a fuel processor plus subsystems to manage air, water, and thermal energy, and electric power. The overall system is high-priced and needs peripheral devices. In this paper, a FC simulator is designed and constructed with the electrical characteristics of a fuel cell generation (FCG) system, using uses a simple buck converter to overcome these disadvantages. The characteristic voltage and current (V-I) curve for the FC simulator is controlled by a simplified linear function. In addition, to verify FCG system performance and operation, a full-bridge DC/DC converter and a single-phase DC/AC inverter were designed and constructed for FC applications. Close agreement between the simulation and experimental results confirms the validity and usefulness of the proposed FC simulator.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.73-76
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• 2008

Bipolar Plates for PEMFC have been a key component of fuel cells with MEA, thus in this research they have been fabricated by a compression molding technique after mixing graphite powder with phenol resin. The results have shown the prominent properties compared with those by foreign advanced company with respect to the electrical conductivity and flexural strength. In addition, it has been carried out that the Voltage-Current characteristics comparison according to the unit cell experiments of bipolar plates. As a result, we have obtained good performances and we are going to research the molding feasibility of bipolar plate's flow channel.

• Proceedings of the KWS Conference
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• 1998.10a
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• pp.129-132
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• 1998

The dynamic resistance monitoring in primary circuit or T/C is one of the important issues in that in-process and real time quality assurance of resistance spot weld is needed to increase the product reliability. It is well known that tile dynamic resistance curve gives us very useful information about nugget growth and weldability. In the present paper, a new dynamic resistance detecting method is presented as a practical manner of weld quality assurance using instantaneous current and voltage measured by primary circuit. Primary dynamic resistance patterns are basically similar to those of the secondary, but there is evident advantage such as no extra devices are needed to obtain the quality assurance index and eventually feedback control will be possible caused by T/C based monitoring system.

• Transactions on Electrical and Electronic Materials
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• v.16 no.5
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• pp.290-292
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• 2015

We have reported about bipolar resistive switching effect on Poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]:Graphene oxide composite films, which are sandwiched between aluminum and indium tin oxide electrodes. In this case, I-V sweep curve showed a hysteretic behavior, which varied according to the polarity of the applied voltage bias. The device exhibited excellent switching characteristics, with the ON/OFF ratio being approximately two orders in magnitude. The device had good endurance (10⁵ cycles without degradation) and long retention time (5 × 10³ s) at room temperature. The bistable switching behavior varied according to the trapping and de-trapping of charges on GO sites; the carrier transport was described using the space-charge-limited current (SCLC) model.

• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.247-251
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• 2008

In this paper. we analyze electrical characteristics of photovoltaic module according to mechanical load test. Using the equipment for giving load on the surface of module, dark current-voltage is measured. By varying load from 0kg to 206kg, slight different I-V curve is detected. From this, reduced shunt resistance is roughly calculated and micro crack is assumed to be happened. system Through this experiment, periodic external force on PV module might give an negative effect. The detailed analysis is described in the following paper.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1063-1066
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• 2006

We report the transparent getter performance of $POCl_3$ and amine based system by using the acid-base reaction in the fastest chemical reaction for top emitting OLEDs. OLED device including synthesized getter component exhibited stable current-voltage curve after 500 hours under $60^{\circ}C$, 90% RH storage condition and showed stable surface performance until 520 hours.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.39-45
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• 2012

Currently, the aircraft industry, aircraft parts as well as airframe have been developed in producing, the aircraft parts and fuselages have been produced the product by cutting rather than forging and casting because of the residual stress and stress concentration. In this study, the aircraft is being used in many parts of aluminium alloy 2024 in wire-cut E.D.M. The selected experimental parameters are peak current, no-load voltage, off time and feed rate. It is found that cutting mountain part on surface roughness of the curve 0.3mm than 0.25mm diameter wire electrode is stable in many uniform distribution.