• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.7-11
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• 2010

Various transmission technologies have been developed to satisfy environmental issues recently. Especially, the technology of the proportional control solenoid valve (PCSV) to ensure high level performance by electronic control has been studied. This study builds an analysis process for designing of the PCSV and characteristic predictions.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1041-1046
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• 2004

A proportional pressure control valve has a nonmagnetic ring which is inserted in between a coil and plunger and it can get attraction force in proportion to input current by an influence of control cone. Therefore, a proportional pressure control valve is applied to a servo system as substitution of servo valve and an on-off solenoid valve widely because control of a high level is possible and pollution level is low. The purpose of this study is to develop domestic model of a proportional pressure control valve, and a test model was designed and manufactured through valve system analysis and finite element analysis. And comparison between results of theoretical analysis and static / dynamic characteristics test were carried out on a manufactured test model, and it was confirmed that it has excellent performance in comparison with other foreign products.

• Journal of the Korean Institute of Navigation
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• v.6 no.2
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• pp.35-55
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• 1982

The attempt of this paper is to examine the basic theory on the analysis of the effect of a shading coil fitted to an electromagnetic contactor, and to compare experimentally the attracting force of an AC electromagnetic contactor with that of a DC electromagnetic contactor, with varying the airgap length. Equations are also proposed for calculating the AC and DC attracting force per unit consumption wattage by using the circuit constants measured from the experiment, and these calculated attracting forces are compared with those actulally measured, and then, the experimental contactor is examined in the view of its design. The calculated attracting forces are appeared to coincide well with the measured ones and the experimental contactor fitted with shading coil is revealed not so well designed for reducing the fluctuation of the attracting force.

• Journal of the Korean Chemical Society
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• v.46 no.6
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• pp.515-522
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• 2002

Solid beta-dicalcium silicate hydrate $(\beta-C_2SH)$ synthesized under hydrothermal conditions at $240^{\circ}C$ and Ca/Si=2 molar ratio shows cation exchange properties towards divalent metal cations such as Fe, Cu, Zn, Cd, or Pb. The ability of metal cation uptake by the solid was found to be in the order: $Fe^{2+}$〉$Cu^{2+}$〉$Zn^{2+}$〉$Cd^{2+}$ = $Pb^{2+}$. Cesium selectivity of the solid was demonstrated in the presence of univalent cation such as $Li^+$, $Na^+$ and $K^+$ and divalent cations such as $Ca^{2+}$, $Mg^{2+}$ and $Ba^{2+}$, which are one hundred times more concentrated than the $Cs^+$. The uptake of $Cs^+$ is maximum in the presence of $Mg^{2+}$ whereas it is minimum in the presence of $K^+$. The different affinities of ${\beta}-C_2SH$ towards divalent metal cations can be used for the separation of those ions. Due to its selectivity for cesium it can be used in partitioning of radioactive Cs+ from nuclear wastes containing numerous cations. The mechanism of the metal cation exchange and cesium selectivity reactions by the solid is studied.

• Journal of the Korean Statistical Society
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• v.1 no.1
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• pp.38-64
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• 1973

본논문은 한국 주요도시의 인구 유출입현상을 통계적으로 구명하고 구명된 결과를 기초로 하여 앞으로의 인구를 예측하는 데에 목적이 있다. 이를 위하여서 간단한 마아코프 연쇄를 이용한 인구이동모형을 선정하고 센서스 자료를 적용하였다. 인구의 예측에는 흔희 단순 L-곡선(simple logistic curve)을 사용하는 것이 일반적인 방법이나 도시인구의 유출입과 같은 사회적 인구증가율을 내포하고 있는 경우에는 적당한 방법이라고 할 수 없겠다. 본논문은 5개의 장과 부록으로 구성되어 있으며 2장에서는 모형과 기초자료의 분석이 있고 3장에서는 모형의 적용, 4장에서는 도시 인구흡인력 등에 관련된 제반 통계량을 추정하였다. 마지막 장은 결과의 평가로 삼았다.

• Geotechnical Engineering
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• v.11 no.3
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• pp.43-54
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• 1995

The aim of the work described in this paper is to develope a constitutive model for the prediction of an unsaturated soil and to confirm the application'of the model, which is composed of the elastic and plastic part in consideration of the matric suction and the net mean stress. From test results, volume changes and deviator stresses are analyzed at each state and their relationships are formulated. The application of the model to silty sands is confirmed by the comparison between test and predicted results. During drying -wetting and loading -unloading processes for isotropic states, the agreement between predicted and test results are satisfactory. Predicted deviator stresses are well agreed with test results in shearing process. Overall acceptable predictions are reproduced in high confining pressure. Usefulness of the model is confirmed for the unsaturated soil except volumetric strain, which is not well agreed with the test results due to deficiency of dilatancy of the model in low confining pressure. It is, therefore. recommended to study the behavior of dilatancy for an unsaturated soil.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1261-1262
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• 2006

Electro-magnetic launcher(EML)는 전자기력을 이용하여 발사체를 추진시키는 장치이다. EML은 크게 레일건의 형태와 코일건의 형태로 구분되며, 본 논문에서는 코일건의 형태로 설계, 제작하였다. 코일건의 형태인 EML은 솔레노이드에 여자되는 전류에 의해서 발사체에 흡인력이 발생하여 추진, 가속되므로 솔레노이드의 최적형태를 설계하고, 이를 바탕으로 제작하여 EML의 스위칭 시간에 따른 속도를 측정하여, 여자전류의 스위칭 시간에 따른 동작특성을 해석, 실험하여 분석하였다.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2227-2228
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• 2006

Electro-magnetic launcher(EML)는 전자기력을 이용하여 발사체를 추진시키는 장치이다. EML은 크게 레일건의 형태와 코일건의 형태로 구분되며, 본 논문에서는 코일건의 형태로 설계, 제작하였다. 코일건의 형태인 EML은 솔레노이드에 여자되는 전류에 의해서 발사체에 흡인력이 발생하여 추진, 가속되므로 솔레노이드의 최적형태를 설계하고, 이를 바탕으로 제작하여 EML의 스위칭 시간에 따른 속도를 측정하여, 여자전류의 스위칭 시간에 따른 동작특성을 해석, 실험하여 분석하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.1
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• pp.43-51
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• 1998

Most of fuel-injection system operated with mechanical methods are difficult to control the injection quantity and injection timing as well as injection rate exactly. Moreover high pressure injection scheme is never be realized with conventional one. On the other hand, serious air pollution can be lessened with injection system equipped with those functions. Therefore, electronically controlled Unit Injuctor(UI) appeared to satify above mentioned desires. However, it is still difficult that the most important part, especially solenoid valve, is analyzed precisely, because of the existence of complex combination of electromagnetics, electrics and dynamic problems. In this study, experimental and theoretical analysis are accomplished for understanding of solenoid valve characteristics and further its design. As the result, the follows are obtained 1) As the increase of wire diameter, the response time became shorter and optimal inductance existed in relative with the response time and wire diameter. 2) According to increasing input voltage, the traction force increased, otherwise the response time was shortened. 3) As the increase of armature stroke, the traction force decreased and the response time became longer.

• Korean Journal of Head & Neck Oncology
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• v.29 no.1
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• pp.18-21
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• 2013

랑게르한스 세포 조직구증은 골수에서 유래하는 랑게르한스 세포 조직구의 이상 증식에 의해 발병하는 희귀한 질병으로 알려져 있다. 비록 모든 장기에서 발생 할 수 있으나 갑상선을 침범하는 경우는 매우 드물다. 18세 남자가 5달전부터 점점 커지는 갑상선 종괴를 주소로 내원하여 세침흡인 세포검사, 총샘검, 경부 전산화단층촬영을 시행하였다. 세침흡인 세포검사에서 악성신생물이 의심되었고, 총생검에서 랑게르한스 세포 조직구증으로 나타났다. 경부 전산화단층촬영에서는 우측 갑상선에서 윤곽이 잘 구분되는 저음영의 종괴와 우측 기관 주위 림프절의 종대가 관찰되었다. 갑상선 전절제술과 우측 중앙 선택적 경부 림프절 청소술이 시행되었다. 랑게르한스 세포 조직구증이 갑상선을 침범하는 경우는 드물지만 갑상선 비대가 있는 환자가 뇌하수체 기능부전의 증상이나 뼈와 폐의 침범과 관련된 증상을 호소한다면 갑상선의 랑게르한스 세포 조직구증 침범을 고려해야 한다. 또한, 다른 장기의 랑게르한스 세포 조직구증을 치료한 과거력이 있는 경우는 갑상선 종괴를 감별 진단하는데 있어 랑게르한스 세포 조직구증을 고려해야 한다.