• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.461-464
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• 2009

The characteristics of slow wave structure employed for backward wave oscillators expected to be a high power microwave source are studied analyytically. The slow wave structure is a sinusoidally corrugated wall waveguide. The waveguide is designed and fabricated by cast aluminun. The dispersion relation and transmitted characteristics for microwaves are measured in the air. There exist literatures on high efficiency of enhanced radiation from backward wave oscillators involving plasma studied experimentally.

• Fibers and Polymers
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• v.2 no.4
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• pp.171-177
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• 2001

Change of tensile properties, electrical conductivity and microwave shielding of electrochemically synthesized polypyrrole films with time are presented. Highly doped films had good electrical stability, retaining high microwave reflectivity throughout the aging period. Lightly doped films were less stable and partially reflective and absorptive of microwaves. FT-IR spectral observations revealed a progressive increase in intensity of an unsaturated conjugated carbonyl peak, which was not observed in the highly doped films, suggesting that the concentration of the dopant had an influence on mechanism of degradation of conductivity.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1283-1284
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• 2015

본 논문에서는 무전극 플라즈마 광원 장치가 무선기기와의 간섭을 최소화하기 위해 협대역 초고주파 발진을 일으키기 위한 전원 개발을 논의한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.169-173
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• 2003

In this paper, we present a design and experiment study of high power large diameter backward wave oscillator. Analysis is made within the scope of linear theory of absolute instibility. The Electron beam generator may be atteractive source of high power millimeter microwaves which has simpler structure.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.779-784
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• 1998

The velocity and amplitude of microwaves are affected by the electromagnetic properties of a material through which the wave propagates. And the electromagnetic properties of a dielectric material such as concrete is represented by its permittivity. For the development of an accurate and reliable nondestructive testing (NDT) technique for concrete structures using microwave, it is necessary to have knowledge about the permittivity of concrete. In this paper, mortar specimens are used to serve as a basis for further measurement of concrete. The effect of water on the permittivity was studied using specimens with different water content. To assure the reliability of the measurement results, a statistical method was introduced.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.374-377
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• 2004

We present a detailed design study of high power large diameter backward wave oscillator operating at 24 GHz for a beam energy of 100 keV. The ratio of the mean diameter of the slow wave structure to the wavelength of output microwaves is increased to be 4.8. Analysis is made within the scope of linear theory of absolute instability.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.2
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• pp.123-130
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• 2015

This paper presents a new formulation for transient simulations of microwave propagation in heterogeneous unbounded domains. In particular, perfectly-matched-layers(PMLs) are introduced to allow for wave absorption at artificial boundaries used to truncate the infinite extent of the physical domains. The development of the electromagnetic PML targets the application to engineering mechanics problems such as structural health monitoring and inverse medium problems. To formulate the PML for plane electromagnetic waves, a complex coordinate transformation is introduced to Maxwell's equations in the frequency-domain. Then the PML-endowed partial differential equations(PDEs) for transient electromagnetic waves are recovered by the application of the inverse Fourier transform to the frequency-domain equations. A mixed finite element method is employed to solve the time-domain PDEs for electric and magnetic fields in the PML-truncated domain. Numerical results are presented for plane microwaves propagating through concrete structures, and the accuracy of solutions is investigated by a series of error analyses.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.6
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• pp.597-602
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• 2008

This paper examines the damage effect and delay time of CMOS integrated circuits device with coupling caused by high power microwaves. The waveguide and magnetron was employed to study the influence of high power micro-waves on CMOS inverters. The CMOS inverters were composed of a LED circuit for visual discernment. Also CMOS inverters broken by high power microwave is observed with supply current and delay time. When the power supply current was increased 2.14 times for normal current at 9.9 kV/m, the CMOS inverter was broken by latch-up. Three different types of damage were observed by microscopic analysis: component, onchipwire, and bondwire destruction. Based on the results, CMOS inverters can be applied to database to elucidate the effects of microwaves on electronic equipment.

• Resources Recycling
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• v.23 no.2
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• pp.46-52
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• 2014

This study was conducted to observe the removal efficiency of oil-contaminated soil by various tests using microwaves and high-temperature heating elements. The water content was measured with the treatment amount, which was lowered to 300g in a relatively short amount of time. The treatment rate of TPH(Total Petroleum Hydrocarbons) showed the highest value with 70.1% when the SiC-activated carbon heating element was at 4 kW/kg, compared to the SiC heating element used alone. In particular, the higher electric power became, the higher treatment rate became, except at 3 kW. In the case of the heating element made by the fusion of SiC and activated carbon, the internal temperature exceeded $300^{\circ}C$ and again fell when it was treated at 4 kW for about 2 minutes. Then, after about 8 minutes, it rose again. On the basis of such results, the energy content necessary for the sample was calculated according to the electric power of microwaves, and tthe constant of TPH treatment was measured by tests on the treatment characteristics of oil-contaminated soil.

• The Korean Journal of Food And Nutrition
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• v.11 no.2
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• pp.228-236
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• 1998

Egg is an important foods containing many good proteins. But it is well known that egg protein has a lot of allergenicity. The purpose of this study is to develop the methods to reduce the allergenicity of egg. I tried various experimental methods ; For example, heat treatment, irradiation with ultraviolet and microwaves, treatment with polyphosphate, enzyme hydrolysis and PCA inhibition test using guinea pigs and degrees of hydrolysis. The results obtained were as follows ; 1. Heat treatment reduced allergenicity of egg protein. The longer the heat time, the better the effect. 2. Irradiating with ultraviolet and microwave increased both the degree of protein hydrolysis and PCA inhibition reduced the allergenicity. Ultraviolet was more effective than microwaves on egg protein. Fertilized eggs did not reduce allergenicity. 3. Enzyme treatment increased the degree of hydrolysis and PCA inhibition, and reduced allergenicity considerably. Alcalase was more effective than neutrase. 4. Adding polyphosphate did not induced protein hydrolysis, but increased PCA inhibition and reduced allergenicity. 5. The picture of various treatments of egg gel by SEM showed a light surface which indicated that protein was desolved. Neutrase was lighter than alcalase, and the longer the heating time, the lighter the surface became. 6. Measurements of the hardness of egg gel by Instron showed that the longer the reaction time with enzyme, the softer it became.