• Journal of the Korean Society for Precision Engineering
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• v.18 no.3
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• pp.90-98
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• 2001

In this paper, the development of exclusive control valve for improving the performance of truck cab tilting system is discussed. Cab tilting system is implemented to the heavy truck for the convenience of driver. However when tilting up or down, sudden swing of cab has brought discredit on user. To improve this phenomena it is inevitable to use counter balance valve. But because of high pressure and low flow characteristic, general counter balance valve is unsuitable to cab tilting system. Therefore, this paper presents the developments of exclusive return pressure control valve which prevents sudden swing of cab and verify the validity of design through the computer simulation.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1994.06b
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• pp.49-53
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• 1994

베인형 펌프, 모터 등의 마찰, 마모특성에 관해서 많은 연구가 있었으나, 베인펌프는 구조로부터의 제약이 많기 때문에, 대용량, 고압, 고속화라는 일련의 요구를 만족시키는 것이 쉽지 않아, 그 요구에 부응하기 위해 지금까지의 연구가 내마모성 작동유, 표면처리 기술, 특수 베인기구등의 개발을 제약에 부딪칠 때마다 필요에 따라 한결같이 경험적으로 이루어졌으며, 측정에 대한 면에서도 동적 조건 하에서의 측정은 거의 없으며, 해석에 관해서도 일반성이 상당히 결여된 상태라 할 수 있다. 따라서 본 연구에서는 유압 베인펌프의 베인과 캠링간의 접동 모델로써 동적 마찰 실험장치를 제작하여, 베인 선단의 마찰력을 측정하고 이를 기초로 하여 실기 유압 베인펌프의 베인과 켐링내면간의 접동부에 관한 마찰특성을 추정하는 것을 목적으로 하였다.

• Journal of the Korean Geosynthetics Society
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• v.3 no.2
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• pp.3-11
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• 2004

Fabric Foam systems provide a variety of flexible bank protection for open channels and hydrulic structures. The structural performance and durability of conventional bank protection materials such as concrete, gravel, riprap and vegetation can be significantly improved by confining the materials within the cells of Fabric Foam system. This paper presents the results of field and laboratory tests carried out to evaluate the performance of new Fabric Foam System as a Bank Protection. The results of the tests confirmed effect of Fabric Foam System in Bank Protection.

• Analytical Science and Technology
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• v.18 no.1
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• pp.5-12
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• 2005

It has been established that soft error of high precision electronic circuits can be induced by alpha particles emitted from the naturally occurring radioactive impurities such as U, and Th. As the electronic circuits have recently become lower dimension and higher density, these alpha-particle emitting radioactive impurities have to be strictly controlled. The aim of this study is to develop of NAA (Neutron Activation Analysis) and gamma-spectrometry to improve the analytical sensitivity and precision of U and Th. A new NAA method has been established using the HTS (Hydrulic transfer system) irradiation facility which has been used to produce radioisotopes for industries and medicines instead of the PTS (pneumatic transfer system) irradiation facility which has been used in general NAA. When the ultratrace impurities have to be analyzed by NAA, background gamma-ray spectra induced from $^{222}Rn$ and its progenies in air is serious problem. This unstable background has been eliminated or stabilized by the use of a nitrogen purging system. Ultra trace amounts of U (0.1 ng/g) and Th (0.01 ng/g) in high purity silica used for EMC could be analyzed by the use of HTS-NAA and low background gamma-spectrometry.