• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.528-533
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• 2005

This paper presents the study of flows at T-junction pipe with orifices. Experiments were carried out for several flow rates, orifice sizes, and pressure differences. Numerical simulations were also done to get more data for the wide range of flow rates. Experimental results and numerical ones are in a good agreement. Due to the effect of T-junction part, the flow rates at the lateral pipe are greater than those at straight pipe for the same pressure differences. When orifices were added, the effects of T-junction part on the ratio of flow rates and the ratio of loss coefficients reduced.

• 동력기계공학회지
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• 제9권4호
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• pp.39-44
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• 2005

This paper presents the study of flows at T-junction pipe with orifices. Experiments were carried out for several flow rates, orifice sizes, and pressure differences. Numerical simulations were also done to get more data for the wide range of flow rates. Experimental results and numerical ones are in a good agreement. Due to the effect of T-junction part, the flow rates at the lateral pipe are greater than those at straight pipe for the same pressure differences. When orifices were added, the effects of T-junction part on the ratio of flow rates and the ratio of loss coefficients reduced.

• Progress in Superconductivity
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• 제13권1호
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• pp.47-51
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• 2011

Mono-atomic-layer graphene is an interesting system for studying the relativistic carrier transport arising from a linear energy-momentum dispersion relation. An easy control of the carrier density in graphene by applying an external gate field makes the system even more useful. In this study, we measured the Josephson current in a device consisting of mono-layer graphene sheet sandwiched between two closely spaced (~300 nm) aluminum superconducting electrodes. Gate dependence of the supercurrent in graphene Josephson junction follows the gate dependence of the normal-state conductance. The gate-tunable and relatively large supercurrent in a graphene Josephson junction would facilitate our understanding on the weak-link behavior in a superconducting-normal metal-superconducting (SNS) type Josephson junction.

• Progress in Superconductivity
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• 제3권1호
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• pp.65-69
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• 2001

We measured the transport properties of$ YBa_2$$Cu_3$$O_{x}$ ramp-edge junction fabricated with interface-engineered barrier. The current-voltage characteristics show a typical resistively-shunted junction like behavior Voltage noise measurement revealed that the main source of the 1/f noise is the critical current and resistance fluctuations. The analysis of the noise data showed that the critical current fluctuations increase with temperature, whereas the resistance fluctuations are almost constant, and both fluctuations are almost correlated. The smaller magnitude of the critical current and resistance fluctuations seems to result from the columnar-deflects.s.

• Progress in Superconductivity
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• 제3권1호
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• pp.60-64
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• 2001

We have studied properties of step-edge Junction prepared with crystal orientation of sapphire substrate. The Step on sapphire substrates fabricated by conventional photolithography method and Ar ion milling method. $CeO_2$ buffer layer and in-situ YBCO thin film were deposited on the stepped sapphire substrates by a pulsed laser deposition method with the predetermined optimized condition. The step angle was centre fled low angle of about $25^{\circ}$. The YBCO film thickness was varied to obtain various thickness ratios of the film to the step height in a range from 0.7 to 1.2. I-V curves of junction were showed RSJ-behavior, double junction structure, and hysteresis due to the crystal orientation of substrate.

• ETRI Journal
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• 제28권5호
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• pp.555-560
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• 2006

A PIN photodiode having a low dark current of 1.35 nA and a high external quantum efficiency of 95.3% fabricated for a passive optical network receiver. As the current was increased under a high voltage of 38 V and a temperature of $190^{\circ}C$, it was observed that there is a threshold current at 11 mA which induces a junction failure. Experimental data suggest that the junction failure occurs due to the crystal breaking at the end facet as a result of thermal heat or energetic carriers. This threshold behavior of junction failure is a valuable observation for the safe treatment of photodiodes. As long as the current is limited below the threshold currents, we have not observed failure events of our photodiodes.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1148-1151
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• 2009

A self-designed, written in labview, Organic Light-Emitting Diode junction temperature measuring program was used to calculate the internal junction temperature for devices during operation, and an infrared thermometer was used to measure the backside temperature of the device substrate, to discuss the effects of the junction and substrate temperature difference to the characteristics of the device.

• 설비공학논문집
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• 제27권7호
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• pp.337-343
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• 2015

This paper investigates the ventilation characteristics in a two-dimensional underground network junction composed of four main lines interconnected by eight ramps. Simple one-dimensional models cannot be applied to network junctions since there are interferences of traffic piston effects in the main lines and at the ramps. A numerical algorithm was developed to analyze the pressure and airflow distributions iteratively. The Darcy-Weisbach equation was used to calculate the piston effects by traffic flows, and a Hardy Cross iteration was conducted for network analysis at the interconnected junction. The results show interesting ventilation characteristics and CO concentration distributions depending on system parameters such as vehicle speed, tunnel diameter, and other junction configurations.

• 산업기술연구
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• 제30권A호
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• pp.83-88
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• 2010

Recently, the LED lighting is widely used to illumination purpose due to its high luminous efficiency and the long life time. However, the light power and lifetime is reduced by junction temperature increment of LED. So it is important to measure the junction temperature accurately. In this paper, we proposed a new design and implementation method of high power LED junction temperature measurement circuit. The proposed circuit has two current sources which are a driving current source and a measurement is verified by experiment, and the result shows that the proposed circuit is appropriate to practical use.

• 전기학회논문지
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• 제58권5호
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• pp.989-993
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• 2009

Triple junction which consists of three media(electrode, insulator, and gas) should be considered in designing of high voltage equipments due to the electric field enhancement. In this paper, positive lightning impulse breakdown voltage is predicted based on the streamer theory for simplified insulator models and 72.5kV spacer with varying the triple junction geometry and gas pressure, and the results are compared to the experimental results. The electric field coefficient concept is also applied in order to evaluate the partial discharge inception voltage and the surface flashover voltage from the streamer inception voltage. The application of this method using the constant electric field coefficient of 1.3 and 0.66 is possible for evaluating the triple-junction insulation of the simplified insulator and the 72.5kV spacer respectively. The error rate is under 10%.