• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.6
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• pp.64-70
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• 2006

The optical element was usually used in optical devices and optical transfer devices, but it has been recently used in communication, computer and medical equipment. With the development of very high speed optical-communication, the development of the kernel parts of optical communication has also increased. Presently, the alignment of the optical element is time consuming, and an effective alignment algorithm has not yet to be developed. In this paper, the alignment automation of the optical element is studied. The ultra precision stage is applied to an optical element alignment to improve the accuracy of the alignment. The automation program of the optical element alignment is developed by LabVIEW programming to save the alignment time. The alignment algorithms of the optical element consist of field search and peak search algorithms.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.139-140
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• 2006

This paper proposes the Embedded Linux System that can overcome the shortcomings of conventional CNC machine system. Linux is free of charge with the open source library and tools that can be used in the development of Kernel. Besides, Application is easily available through countless open source, allowing simple mending for seamless porting. This study have developed the study about NC Program automation Load System based on Embedded Linux and the ordered controller.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.669-672
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• 2006

고온가스냉각 원자로에서는 고온 안정성 및 핵분열생성물 차단 성능이 우수한 TRISO(tri-tsotropic) 핵연료를 사용하고 있다. TRISO 핵연료 입자는 직경이 약 1 mm인 구 형태로 입자의 중심에는 직경 $0.5{\mu}m$의 핵연료 커널(kernel)이 포함되며 커널 외곽을 코팅 층이 에워싸고 있다. 이 코팅 층은 완충(buffer) PyC(pyrolytic carbon) 층, 내부 PyC 층, SiC 층, 그리고 외부 PyC 층으로 구성되어 있다. 각 코팅 층의 두께는 수십${\sim}$백 ${\mu}m$ 범위이며, 본 연구에서는 각 코팅 층의 두께를 비파괴적으로 측정하기 위하여 마이크로포커스 X-선 발생장치와 고해상도 X-선 평판(flat panel) 검출기로 구성된 정밀한 X-선 래디오그래피 장치를 구성하고, $UO_2$ 핵물질 대신에 $ZrO_2$를 커널로 사용한 모의 TRISO 핵연료 입자에 대한 래디오그래피 영상을 획득한 후 디지털 영상처리기술을 이용하여 코팅 층 사이의 경계선이 구분 가능하도록 영상을 개선하고 디지털 영상처리 알고리즘을 개발하여 코팅 층의 두께를 측정하였다.

• Journal of Powder Materials
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• v.19 no.6
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• pp.398-404
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• 2012

This paper describes the spherical ammonium diuranate gel particles which are the intermediated material of the $UO_2$ microsphere for an VHTR(very high temperature reactor) nuclear fuel. The characteristics of the intermediate-ADU gel particles prepared by AWD(ageing, washing, and drying) and FB(fluidized-bed) apparatus were examined and compared in a sol-gel fabrication process. The electrical conductivity of washing filtrate from the FB treating and the surface area of dried-ADU gel particles were higher than those of AWD treating. Also, an internal pore volume in dried-ADU gel particles showed a more decrease in AWD treatment than FB treatment because of decomposition of PVA affected by the washing time. However, the internal microstructures of ADU gel particles were similar regardless of the process variation.

• Journal of the Korean Ceramic Society
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• v.45 no.11
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• pp.725-733
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• 2008

In this study the preparation method of the spherical ADU droplets, intermediate compound of a HTGR nuclear fuel, was detailed-reviewed and then, the characteristics on an ageing and a washing steps among the wet process and the thermal treatment process on the died-ADU${\rightarrow}UO_3$ conversion with the high temperature furnaces were studied. The key parameters for spherical droplets forming are a precise control of feed rate and a suitable viscosity value selection of a broth solution. Also, a harmony of vibrating frequency and amplitude of a vibration dropping system are important factor. In our case, an uranium concentration is $0.5{\sim}0.7mol/l$, viscosity is $50{\sim}80$ centi-Poise, vibration frequency is about 100Hz. In thermal treatment for no crack spherical $UO_3$ particle, the heating rate in the calcination must be operated below $2^{\circ}C$/min, in air atmosphere.

• Journal of the Korean Society of Combustion
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• v.22 no.2
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• pp.36-41
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• 2017

Aero gas turbine engines must demonstrate their ability to be ignited on ground conditions or relighted in flight. The electric spark ignition is usually used in current aero gas turbine engines. Experiments on ignition characteristics relating to spark igniter penetration depth under atmospheric pressure and temperature conditions were conducted on the model combustor which is scaled in 1/18. Exciter was operated during 2 seconds, and successful ignition phenomena were confirmed by the pressure rising sharply in combustor. In addition, instantaneous ignition images were captured by a high-speed camera. It showed kernel propagation and successful ignition events in the sector model combustor. Ignition test results showed that ignition limit with increase in penetration depth of the igniter plug was wider. When the penetration depth of the igniter plug increased under the same fuel injection pressure condition, successful ignition events were obtained in higher differential pressure conditions between inlet and outlet of the combustor. The results demonstrate that the ratio of the combustible mixture, which is exposed to the high temperature environment around the igniter plug tip, increases. Thereby affect the combustor ignition performance.

• Korean Journal of Materials Research
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• v.30 no.10
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• pp.533-541
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• 2020

UO₂ kernels, a key component of fuel elements for high temperature gas cooled reactors, have usually been prepared by sol-gel methods. Sol-gel processes have a number of advantages, such as simple processes and facilities, and higher sphericity and density. In this study, to produce 900 ㎛-sized UO₂ particles using an external gelation process, contact length extension of the NH₃ gas of the broth droplets pass and the improvement of the gelation device capable of spraying 14 M-NH₄OH solution are used to form 3,000 ㎛-sized liquid droplets. To produce high-sphericity and high-density UO₂ particles, HMTA, which promotes the gelation reaction in the uranium broth solution, is added to diffuse ammonium ions from the outside of the gelation solution during the aging process and generate ammonium ions from the inside of the ADU gel particles. Sufficient gelation inside of ADU gel particles is achieved, and the density of the UO₂ spheres that undergo the subsequent treatment is 10.78 g/㎤; the sphericity is analyzed and found to be 0.948, indicating good experimental results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.993-998
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• 2002

Ultra precision processing technology is the field which is seriously protected its technology by advanced nations. Because of this reason, this technology is very difficult to supply for domestic companies, also domestic companies are revealed the limit of technology development by itself. And then, those are depend on the technology development of advanced nation, domestic companies are not conquer application step with already developed parts. Of course, some cases of its research are succeed. those are included element technology, system technology and so on, for development of ultra precision processing system. To conquer technology holding ultra precision processing accuracy of no level, active research are needed. In this paper, stability of ultra precision cutting unit is analyzed, this unit is the kernel unit in ultra precision processing machine. According to alteration of shape and material about hinge, stability investigation is performed Through this stability investigation, trial and error is reduced in design and manufacture, at the same time, we are accumulated foundation data for un it control.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.297-297
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• 2022

Wheat is the staple food crop in the word, but wheat products have a low bioavailability of iron and zinc. So in the developing world, where wheat is a staple food, it suffers from micronutrients deficiency. This study was conducted to generate wheat varieties with enhanced grain Zn and Fe contents. Sixty wheat resource were cultivated over 2 years (2019-2021) in the field of NICS, Jeonju, Republic of Korea, to identify agronomic traits. Wheat grains were ground using grinder and analyzed whole wheat flour protein contents and Fe and Zn contents using ICP-OES. The average contents of Zn and Fe grain were 4.6 mg/100g (2.4~8.8 mg/100g) and 4.5 mg/100g (2.4~7.9 mg/100g), respectively. The contents of Fe and Zn in the wheat grain had a positive correlation with the protein content of whole wheat flour, but there was no correlation with heading date (4.22~5.27) and the thousand kernel weight (21.3~57.5 g). Although there was year variation, six resources with high contents of Fe (>5.2 mg/100 g) and Zn (>5.3 mg/100 g) grain in 2 years were selected. These results provide information for selecting breeding materials for biofortified wheat, and further studies on germplasms genetic variations and bioavailability are needed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.2048-2054
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• 2013

Due to the development of the digital technology, the territories of broadcasting and telecommunications are being converged and there have been the efforts to eliminate the spatial and/or temporal restrictions in utilizing the services (usually implemented as applications) via various devices (e.g. smart-phone, smart TV, pad-computer, etc). In the circumstances, Web is coming to the fore as a common running platform of the services and the digital broadcasting receivers are pressed to run Web applications as well as Java applications, which are the standard of data service of the digital broadcasting. The paper introduces a platform for running HTML5-based Web applications, which is equipped with a Web kernel (an engine for running HTML5 Web applications), a Web desktop (the facilities (with an UI similar to Window OS) for managing Web applications), and SDK (a set of API's for Web application developers).