• Korean Journal of Food Science and Technology
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• v.11 no.4
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• pp.258-263
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• 1979

A cylindrical focusing solar food dryer made with aluminum-laminated acryl film was demonstrated for the dehydration of agricultural product and its perfomance was analyzed with respect to the solar energy utilization and its scale-up technology. With one square meter reflector and a 74 cm copper pipe absorber, the heat exchange efficiency between air stream and absorber was 1.39 %. The installation of circular segment-baffle increased 33 % of the efficiency. In dehydration of radish-cut with this drier, 58 % of fuel consumption was saved. The relationship between reflector area and heat energy utilization was established for the scale-up purpose.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.339-345
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• 2018

We investigated the curing properties of cured coatings for a multi-focal UV-LED. The coatings are for LEDs that operate at multiple UV wavelengths, unlike conventional single-wavelength UV-LEDs. Using UV-LED light sources with wavelengths of 365, 395, 420, and 450 nm, we analyzed the optical characteristics such as the direction of light flux and light source. We also analyzed the curing characteristics at each UV-LED wavelength to optimize the LED for composite wavelengths. The curing performance state was predicted through computer simulation for when the multiple wavelengths of UV light sources are superimposed, and then actual LEDs were designed and fabricated. To improve the internal high-speed curing, a multi-spot module was fabricated, in which each LED is condensed, and multiple wavelengths are synthesized and condensed at the same position. The adhesive strength, surface hardness, and internal hardness of the curing agent were tested by varying the wavelength combination conditions. The surface hardening and internal hardening were compared and analyzed using a hardness tester and FT-IR analyzer. As a result, the characteristics of the surface and internal hardness were improved by a multi-spot method in which four wavelengths were overlapped in a UV-LED rather than a single wavelength.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.3
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• pp.252-259
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• 2008

The deep-sea mining system is generally composed of surface vessel, lifting system, buffer, flexible pipe and miner. The mining system can be regarded as a large-scale system in which each subsystem is interconnected to other ones. In order to control a large-scale system, decentralized control approaches have been proposed recently. In this paper, as a basic study on application of decentralized control, firstly, the mining system was modeled in a simplified way. Lifting system and buffer were regarded as a spherical pendulum and the flexible pipe was taken as a two-dimensional linear spring connection. Based on the simplified model dynamics, the mining system can be decentralized two subsystems, the one consisting of surface vessel, lifting system and buffer, and the other, the miner. Next, this paper proposed the design of controller for each decentralized subsystem by regarding the interacting terms as disturbances. The controllers kept the constant distance between two subsystems during the miner was moving on the specified track. Finally, the efficiency of proposed controller was proven through the numerical simulation of the derived model.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.547-548
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• 2009

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.545-546
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• 2009

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.88-89
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• 2009

• Proceedings of the Optical Society of Korea Conference
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• 2005.07a
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• pp.282-283
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• 2005

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.222-223
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• 2004

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.455-460
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• 1996

원자력발전소의 전열관 보수용접 기술 개발을 위해 Inconel 600 재질의 plate 판에 레이저 용접실험을 수행하였다. 레이저 발진기로 부터 발진된 레이저 빔은 광섬유를 통하여 전송되고, 집광렌즈군를 이용하여 용접이 이루어지도록 하였다. pulse 레이저 용접 변수인 펄스폭, 반복율, 첨두출력 및 용접속도를 변화시키면서 용접결과를 측정하였다. 이에 따른 적절한 용접범위를 제시하였다.

• Proceedings of the Safety Management and Science Conference
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• 2011.11a
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• pp.335-343
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• 2011