• Journal of the Korean Institute of Telematics and Electronics A
• /
• 제33A권10호
• /
• pp.139-143
• /
• 1996

We report on the static and dynamic characteristics of optically modulated resonant tunneling diode oscillator (RTDO) formed in double-barrier quantum-well structure. Under the illumination of Ti:Sapphire laser, the dc current-voltage (I-V) curves of RTDO shifted towared lower voltages. This characteristic was found to odify the series resistance, negtive differential resistance, capacitance, and the inductance of the RTDO. As a result, the resonant frequency of TRDO centered at 5.302 GHz was found to decrease about 20 MHz under the laser illumination. At a constnat bias voltage, the oscillation frequency decreased linearly as the laser power was increased.

• Proceedings of the Korea Concrete Institute Conference
• /
• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
• /
• pp.155-158
• /
• 1995

High durabitiy concrete increasingly sutudied in various countries. This report presents the data on durability related properties such as the chloride ion permeability, the resistance to freezing-thawing, the corrosion of steel and the resistance attack. To promote the actual application of high durability concrete, several series of high durability concrete have been made and applied to actual structures.

• Journal of Advanced Marine Engineering and Technology
• /
• 제8권2호
• /
• pp.67-73
• /
• 1984

The Author researched and published its results on how effectively the arcs suppressed when the contactors are opened at current zero point which indispensively exsists in AC circuits. In order to increase the effectiveness of suppressing the arcs in larger current, the author suggests a new suppressing method using auxiliary contactor which contains resistance which is connected in parallel with main contactor. The author's firm belief is that the arcs are suppressed remarkably, but there are several problems, especially how to determine the optimal resistance connected in series with auxiliary contactor.

• Journal of the Korean Society of Safety
• /
• 제13권3호
• /
• pp.74-79
• /
• 1998

To establish measuring method for minimum ignition energy of explosive powders caused by electrostatic discharge, A measuring method(Hartman) using a very small quantity of pine tree testing powder was proposed, and the influence of discharge current limiting resistance connected in series into a capacitive discharge circuit on ignition energies of explosive powders was investigated. As a result the minimum ignition energy was 42.25mJ when discharge current limiting resistance 300 $k\Omega$.

• Proceedings of the KIPE Conference
• /
• 전력전자학회 2014년도 전력전자학술대회 논문집
• /
• pp.542-543
• /
• 2014

In this paper, an estimation scheme based on an augmented sigma-point Kalman filter to estimate the state of charge (SOC) of the battery is presented, where the battery parameters of the series resistance ($R_o$), diffusion capacitance ($C_1$) and resistance ($R_1$) are also estimated through the recursive least squares (RLS) for better accuracy of the SOC. The effectiveness of the proposed method is verified by simulation results.

• Proceedings of the KIEE Conference
• /
• 대한전기학회 1985년도 하계학술회의논문집
• /
• pp.341-343
• /
• 1985

In designing the high frequency oscillator with FET, it may be necessary to make the FFT unstable using feedback. For convenient realization, sir feedback type is usually employed. It is convenient to determine the load which makes oscillation possible, with the contour plot of the negative resistance of the FET positively feedback for each type. Analytic formulas are given for this contour plot in this paper, and the results are discussed.

• 한국기계연구소 소보
• /
• 통권9호
• /
• pp.153-167
• /
• 1982

From first-order thin-ship theory, we can obtain the" wave resistance, wave amplitude functions, wave elevation along the hull, sinkage and trim of a ship moving with constant speed into calm water. Generally, these calculations of ship is called with Michell’s Theory, and there is all the difference between calculated wave resistance and residual resistance from conventional wave resis¬tance test. But, these calculated results are important reference materials for initial hull form design procedure. Various calculated results for Shearer’ s Model, Wigley’s Model and Series 60 4210W Model have been calculated using this theory. The results are compared with the corresponding experimental values, and the agreement between theoretical and experimental values is considered satisfactory.

• Journal of the Society of Naval Architects of Korea
• /
• 제47권3호
• /
• pp.398-409
• /
• 2010

This paper considers the numerical computation of added resistance on ships in the presence of incident waves. As a method of solution, a higher-order Rankine panel method is applied in time domain. The added resistance is evaluated by integrating the second-order pressure on the body surface. Computational results are validated by comparing with experimental data and other computational results on a hemi-sphere, a barge, Wigley hull models, and Series 60 hull, showing very fair agreements. The study is extended to the comparison between Neumann-Kelvin and double-body linearization approaches, and their differences are discussed.

• Bulletin of the Society of Naval Architects of Korea
• /
• 제19권2호
• /
• pp.19-25
• /
• 1982

Several formulae have been proposed to estimate the viscous resistance of ships by wake surveys. Both the total head and the velocity should be measured. The integration of he total head loss shows over estimations of the resistance by about 10%. Therefore measurements of the velocity are required, which need much more works. A simple method is suggested in this paper to take accout of the velocity-defect from the measured total head. It gives reasonable estimations of the viscous resistance within the experimental accuracy. Experimental data of a low-drag body of revolution in the wind-tunnel and Series 60 model, CB=0.6 in the tank are used to verify the suggested formula.

• Bulletin of the Society of Naval Architects of Korea
• /
• 제20권4호
• /
• pp.25-32
• /
• 1983

A series of model testes on a container ship in regular were executed. This paper presents the results of resistance, self-propulsion, and ship motion tests. The experimental results of ship motion measured on a towed model and a self-propelled model were compared with those of Japanese's model test showing fairly good agreements. The results of added resistance tests were compared with those of Japanese' model test and also compared with the calculation results by Gerritsma's method showing somewhat large discrepancies at higher speeds. Also the results of added resistance tests measured on a fixed model were compared with the calculation results by Gerritsma's method. Finally the results of self-propulsion tests were presented.