• Macromolecular Research
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• v.17 no.1
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• pp.26-30
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• 2009

To modify and strengthen the properties of PHEMA hydrogel, composite hydrogels containing varying amounts of a Pluronic (PEO-PPO-PEO) component were synthesized by bulk polymerization of HEMA in the presence of Pluronic dimethacrylate under mild photo initiating conditions. The effects of the Pluronic component on gel properties were investigated by measuring the degree of swelling with its temperature responsive behavior, the mechanical properties, and the morphology of the composite hydrogels. With increased Pluronic content, the modified PHEMA hydrogels exhibited an increase in the degree of swelling, and the swelling showed an enhanced thermo-responsive behavior that was completely reversible. In addition, improved mechanical strength and the development of a microporous gel morphology were observed in hydrogels containing Pluronic.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.36-41
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• 2008

Fault detection and diagnosis(FDD) system is beneficial in equipment management by providing the operator with tools which can help find out a failure of the system. An experimental study has been performed on fault detection and diagnosis method for a water chiller. Bayes classifier, which is one of classical pattern classifiers, is adopted in deciding whether fault occurred or not. FDD algorithm can detect refrigerant leak failure, when 20% amount of charged refrigerant for normal operation leaks from the water chiller. The refrigerant leak failure caused COP reduction by 6.7% compared with normal operation performance. When two kinds of faults, such as a decrease in the mass flow rate of cooling water and temperature sensor fault of cooling water inlet, are detected, COP is a little decreased by these faults.

• Nuclear Engineering and Technology
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• v.43 no.4
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• pp.383-390
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• 2011

Nuclear power has become an essential part of electricity generation to meet the continuous growth of electricity demand. A Sodium-cooled Fast Reactor (SFR) was developed to extend uranium resource utilization under a growing nuclear energy scenario while concomitantly providing a nuclear waste management solution. Key questions in this scenario are when to introduce SFRs and how many reactors should be introduced. In this study, a methodology using Linear Programming is employed in order to quantify an optimized growth pattern of a nuclear energy system comprising light water reactors and SFRs. The optimization involves tradeoffs between SFR capital cost premiums and the total system U3O8 price premiums. Optimum nuclear growth patterns for several scenarios are presented, as well as sensitivity analyses of important input parameters.

• Journal of Plant Biology
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• v.39 no.1
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• pp.9-13
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• 1996

A clone, LCM1, which encodes calmodulin (CaM) was isolated and characterized from monocot lily (Lilium longiflorum Thunb.) plants. The clone is 681 bps and contains the 447 bp coding region, 8 bp leader sequence, 210 bp 3'-untraslated region, and a poly(A) tail. The coding region of 149 amino acids encodes a protein of predicted Mr 17 kD. Comparison of the LCM1 amino acid sequence with other CaMs revealed that the protein is highly conserved among various living organisms. The expression level of calmodulin gene in lily was studied by RNA blot analysis. The LCM1 mRNA was present in all tissues tested. However, a higher level of calmodulin was observed in anther and floral bud. The level of calmodulin mRNA in anther was about 10 times higher than that in anther was about 10 times higher than that in vegetative tissues. The anther preferential expression of CaM in lily is currently investigated in dicot plants.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.443-448
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• 1998

With using artificial neural networks (ANNs), an analytical study related to the heated length effect on critical heat flux(CHF) has been carried out to make an improvement of the CHF prediction accuracy based on local condition correlations or table. It has been carried out to suggest a feasible criterion of the threshold length-to-diameter (L/D) value in which heated length could affect CHF. And within the criterion, a L/D correction factor has been developed through conventional regression. In order to validate the developed L/D correction factor, CHF experiment for various heated lengths have been carried out under low and intermediate pressure conditions. The developed threshold L/D correlation provides a new feasible criterion of L/D threshold value. The developed correction factor gives a reasonable accuracy fur the original database, showing the error of -2.18% for average and 27.75% for RMS, and promising results for new experimental data.

• Journal of the Korea Safety Management & Science
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• v.10 no.1
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• pp.75-82
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• 2008

National technical qualification does not recognised degree of working-career in labor market and an industrial field situation. National qualification is supply to nurture expert manpower and accomplish of self-development and a duty accomplishment ability improvement at a side of personal. So, This study is purposed to find that a method for recognition of working-career on the national technical qualification system According to, this study is designed to questionnaire with BSC(Balaced ScoreCard), SEM(Structure Equation Model) with the delphi method, and is analysed using the AMOS 7.0 program package. Finally, This study is suggested growing to qualification standard for an examination a degree of master craftsman only under the change of national qualification systematization as a standard to operation and control.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.363-368
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• 2004

Maglev vehicles, which are levitated and propelled by electromagnets, often run on elevated guideways comprised of steel, aluminum and concrete. Therefore, an analysis of the dynamic interaction between the Maglev vehicle and the guideway is needed in the design of the critical speed, ride, controller design and weight reduction of the guideway. This study introduces a dynamic interaction simulation technique that applies FEM. The proposed method uses FEM to model the elevated guideway and the Maglev vehicle, which is different from conventional studies. Because the proposed method uses FEM, it is useful to calculate the deformation of the elevated guideway, the dynamic stress, and the motion of the vehicle. By applying the proposed method to an urban transit Maglev vehicle, UTM01, the dynamic response is simulated according to velocity increase and can be reviewed again. From the result of the study, we concluded that FEM simulation of the dynamic interaction between the maglev vehicle and the guideway is possible.

• ETRI Journal
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• v.34 no.2
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• pp.210-215
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• 2012

In this paper, a group delay time controller (GDTC) is proposed based on a reflection topology employing a parallel resonator as the reflection termination. The design equations of the proposed GDTC have been derived and validated by simulation and experimental results. The group delay time can be varied by varying the capacitance and inductance at an operating frequency. To show the validity of the proposed circuit, an experiment was performed for a wideband code division multiple access downlink band operating at 2.11 GHz to 2.17 GHz. According to the experiment, a group delay time variation of $3{\pm}0.17$ ns over bandwidth of 60 MHz with excellent flatness is obtained.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.63-64
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• 2006

In this paper, the open loop antenna using a strip-conductor for an RFID reader at dual-band frequency(910MHz, 2.45GHz) is proposed. The impedance is matched by varying the antenna parameters such as the length of strip-conductor and the gap of between two strip-conductors. Return loss and gain of designed antenna are -11.919dB, 2.5dBi at 910MHz, and -15.766dB, 5.65dBi at 2.45GHz, respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.717-720
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• 2008

This paper, an evaluation of the mechanical property for the backfilling materials of the NATM Composite lining tunnel using the lightweight foamed mortar, relates to the performance of permeability, compressive strength and unit volume weight. Therefore, this study is aimed to prove the three main factor that refered to the above line for development of new tunnel method. As the result of this study, it would be confirmed that the D mix is better than other mixs a side of all tests and its relation that is for the tunnel backfilling materials.