• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.147-151
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• 2001

본 논문에서는 두 동축케이블을 사용한 고주파용 결합기 설계 시 결합폭, 외경과 내경의 비 그리고 결합길이의 변수 변화에 따른 특성을 나타내었다. 또한 두 개의 동축케이블 사이에 금속봉을 삽입하여 고주파 대역에서 결합도가 향상된 새로운 구조를 제안하였다. 본 논문에서 제시한 구조는 일반적인 구조에 비하여 지향성과 반사손실 특성을 유지시키면서 결합도가 약1.8 dH 향상되었다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1566-1567
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• 2011

일반적으로 배전반과 변압기와 같은 고전압 전력기기를 운전하는 경우에는 외부 환경에 의한 열화특성뿐만 아니라 전력기기 내부의 구조적 특성에 의한 절연적 특성 변화가 발생하게 된다. 따라서 고신뢰성의 고전압 전력기기를 설계하기 위해서는 이와 같은 점을 고려한 내부 설계가 이루어져야 한다. 본 연구에서는 접지부에 여러 가지 형상을 가지는 볼트와 같은 구조물을 위치시키고 그에 따른 절연파괴전압의 변화에 대한 연구를 수행하였다. 동일한 전극 간격에 대한 AC 전압의 특성변화를 실험을 통하여 측정하고 분석하였다. 실험 결과, 절연파괴전압은 접지측에 위치한 볼트의 형상에 따라 크게 변화한다는 사실을 알 수 있었으며, 이와 같은 결과는 고전압 전력기기를 설계 및 제작하는데 큰 도움이 될 수 있을 것으로 판단된다.

• Korean Journal of Optics and Photonics
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• v.17 no.4
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• pp.371-380
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• 2006

We design and fabricate a novel tunable wavelength filter, which utilizes long-range surface plasmon-polaritons excited along nm-thick-metal strips. A gold metal strip, with $\sim$ cm length, 20 nm thickness, and $\sim$ 5$\mu$m width, is embedded in thick thermo-optic Polymer films supported by a silicon wafer. A dielectric Bragg grating structure is Placed on the metal strip, so that transmission signals at telecom wavelength are selected by thermal effect of the thermo-optic polymer. High extinction ratio of 25 dB and total insertion loss of $\sim$25 dB/cm can be measured by single-mode coupling of optical fibers. We also verify that wavelength tuning of the long-range surface plasmon-polariton filters can be achieved by electric current directly applied to the metal-strip waveguides.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.61-65
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• 2006

A thery was developed to design a high pressure vessel with combined structure of the metal and the composite to withstand the pressure of several tens of thousands psias to reduce the weight of the impulse motor which produces high level of thrust within several tens of seconds. The elastic-plastic stress analyses were carried out to prove the validity of the design theory A combustion chamber of the impulse motor was designed by the design theory, fabricated, and tested by the hydraulic pressure and the static firings. The bursting pressures from the tests were compared to those predicted by tile design theory and the stress analyses and found to be almost the same. It will be possible to design the high pressure vessel with combined structure of the metal and the composite very easily by the proposed design theory.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.2
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• pp.23-30
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• 2006

A thery was developed to design a high pressure vessel with combined structure of the metal and the composite to withstand the pressure of several tens of thousands psias to reduce the weight of the impulse motor which produces high level of thrust within several tens of seconds. The elastic-plastic stress analyses were carried out to prove the validity of the design theory. A combustion chamber of the impulse motor was designed by the design theory, fabricated, and tested by the hydraulic pressure and the static firings. The bursting pressures from the tests were compared to those predicted by the design theory and the stress analyses and found to be almost the same. It will be possible to design the high pressure vessel with combined structure of the metal and the composite very easily by the proposed design theory.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.11
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• pp.767-773
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• 2017

Printed Circuit Heat Exchanger (PCHE) has an advantage for exchanging thermal energy between high-pressure and high-temperature fluids because its core is made by diffusion bonding method of accumulated metal thin-plates which are engraved of flow channel. Moreover, because it is possible that the flow channel can be micro-size hydraulic diameter, the heat transfer area per unit volume can be made larger than traditional heat exchanger. Therefore, PCHE can have higher efficiency of heat transfer. The smaller channel size can make the larger heat transfer area per unit volume. But if high pressure fluid flows inside the channel, the channel wall can be deformed, the structure and shape of flow channel and header have to be designed appropriately. In this study, the design methodology of PCHE channel in high pressure environment based on pressure vessel codes was investigated. And this methodology was validated by computational analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.4A
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• pp.256-266
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• 2003

In this paper, scattering characteristics of the rectangular waveguide with elliptical conducting post and equivalent impedance of post are analyzed by mode matching method and generalized scattering method. The scattcring characteristics of rectangular waveguide are varied by the height and eccentricity of elliptical conducting post. When the height of post(2.54mm, 4mm) is small, variation in scattering characteristics appears in total simulated frequency. But as the height of post(7.62mm, 9mm) is increased, it is dominant in higher frequency. The simulated result shows good agreement with the HFSS's result. Proposed structure and analysis method are easily applied to the design and manufacture of waveguide component with elliptical conducting post.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.4
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• pp.69-74
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• 2010

A new package substrate for dynamic random access memory(DRAM) devices has been developed using selective aluminum anodization. Unlike the conventional substrate structure commonly made by laminating epoxy-based core and copper clad, this substrate consists of bottom aluminum, middle anodic aluminum oxide and top copper. Anodization process on the aluminum substrate provides thick aluminum oxide used as a dielectric layer in the package substrate. Placing copper traces on the anodic aluminum oxide layer, the resulting two-layer metal structure is completed in the package substrate. Selective anodization process makes it possible to construct a fully filled via structure. Also, putting vias directly in the bonding pads and the ball pads in the substrate design, via in pad structure is applied in this work. These arrangement of via in pad and two-layer metal structure make routing easier and thus provide more design flexibility. In a substrate design, all signal lines are routed based on the transmission line scheme of finite-width coplanar waveguide or microstrip with a characteristic impedance of about $50{\Omega}$ for better signal transmission. The property and performance of anodic alumina based package substrate such as layer structure, design method, fabrication process and measurement characteristics are investigated in detail.

• Journal of the Microelectronics and Packaging Society
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• v.2 no.2
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• pp.1-8
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• 1995

전자세라믹 부품으로 널리 사용되는 압전세라믹 발음체 디바이스의 응용과 그종류 를 분류하였고 특징, 구조와 작동원리 압전체로 사용되는 재료의 조성, 전극재료, 금속진동 판의 종류와 물성 압전반응체의 제조공정, 음향설계와 향후의 전망에 대하여 해설하였다.

• Korean Journal of Optics and Photonics
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• v.28 no.6
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• pp.361-365
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• 2017

In this paper, we demonstrate a facile fabrication technique for a periodically aligned metal nanoparticle array, for a narrow-band plasmonic absorber. The metal nanoparticles are fabricated by e-beam evaporation and heat treatment processes on top of a periodic aluminum groove template. The plasmonic absorber is constructed with the transferred metal nanoparticle array, sputtered 33-nm-thick $Al_2O_3$, and 200-nm-thick metal reflector layers on silicon substrate. 46-nm-diameter and 76-nm-lattice metal-nanoparticle-array-based plasmonic absorber has performed as a narrow-band absorber with a central wavelength of 572 nm and full width at half maximum (FWHM) of 109.9 nm.