• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.929-936
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• 1995

LOMI 제염제의 전기화학적 제조공정 중 전하운반체의 역할 및 V$^{3+}$ 이온의 침전현상을 방지하기 위하여 첨가되는 과량의 formic acid 는 제염제 제조시에는 중요한 역할을 하지만 제염 폐기물의 양을 증가시키는 요인이 되기도 한다. EPRI 공정에서는 formate : V 의 비율(FVR)이 10:1 인 조건에서 V$^{2+}$-formate 를 제조한 후 음이온 교환 수지를 이용하여 과량의 formate 를 제거하는 공정을 사용한다. 이러한 방법으로 줄일 수 있는 FVR의 한계가 약 2.5 : 1 이다. 본 연구에서는 제염제 중 formate 의 양을 더욱 줄일 수 있는 방법으로써 V$^{2+}$-formate 제조시 용액 중에 picolinic acid를 미리 첨가하는 영향을 조사하였다. V$^{2+}$ 이온의 농도가 0.1 M 일 때 FVR 를 1.5:1 까지도 줄일 수 있음을 확인하였다.

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.2
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• pp.105-113
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• 2003

The pyrolysis for production of hydrogen and high quality carbon black from natural gas were studied. The reactivities in tubular reactor and FVR(free volume reactor) for the methane pyrolysis were compared, in order to prevent the formation of undesirable carbon product such as pyrocarbon, the FVR was designed. The hydrogen yield and the formation of carbon black from methane pyrolysis in this reactor were investigated at temperature range between 1443 and 1576K. From the result of TEM (transmission electron microscopy) analysis, it was confirmed that the CFC(catalytic filamentous carbon) was formed without pyrocarbon.

• Journal of the Korean Society for Library and Information Science
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• v.48 no.1
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• pp.195-214
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• 2014

The purpose of the study is to suggest a conceptual framework for the vacation reading programs in promoting children's love of reading in public libraries. Within the conceptual framework of free voluntary reading (FVR), the study identified the concept of reading that public libraries should pursue in developing children's reading programs and analyzed current vacation reading programs that four public libraries in Seoul held during winter and summer vacations of 2013. More specifically, the study analyzed (1) their purposes, (2) durations, targeted children groups, the number of children users, (3) their instructors, (4) the content design of the programs, (5) selected books, and (6) completion certificates and rewards for participation. Lastly, the study discussed whether the programs satisfied the characteristics for promoting free voluntary reading and played the roles for vacation reading programs in public libraries. The results of the study suggest the need for shifting the current vacation reading programs to be more inclusive, so that more children can develop to learn love of reading.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.4
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• pp.170-178
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• 2001

Deadbeat technique has been proposed as a digital controller for an UPS inverter to achieve the fast, response to a load variation and to conserve a very low THD under a nonlinear load condition. This scheme contains a fatal drawback, sensitivity against parameter variation and calculation time delay. This paper proposes a second order deadbeat controller, which fundamentally solves the calculation time delay problem and certainly guarantees the robustness of the parameter's variation. RLP(Repetitive Load Predictor) which predicts the load current ahead of two sampling time and FVR(Fundamental Voltage Regulator) which eliminates the fundamental errors of the output voltage are also proposed for the second order deadbeat controller to apply to UPS inverter systems. These are shown theoretically and practically through simulation and experiment.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.1
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• pp.77-83
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• 2013

This paper presents the feasibility on the application of composite coil spring, which has great interest in the automobile industry. In order to obtain much lighter weight of the composite spring, it will be necessary to optimize the design variables such as fiber angles and diameter of coil, etc. First of all, mechanical properties were measured to consider the effects of FVR and ply angles for carbon fiber composite material. And the shear modulus with respect to ply angles were derived based on twisting angles calculated by torsional beam model. Next we determined the design parameters of composite coil spring, which has equivalent spring rate to the steel coil spring. In order to assess the proposed method, finite element model of the composite spring was developed and analysed to obtain the spring constant. The results showed that static spring rate of the composite spring was in a good agreement with that of steel spring.