• Journal of the Korean Society of Safety
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• v.15 no.1
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• pp.86-92
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• 2000

Recently, more advanced electronic elements become, they consume powerful and radiate more heat in devices. So the most suitable packaging technique is keenly needed. The most important purpose of packaging is to protect devices within a system for a long time and to prevent life of devices from external environments; floating ions such as humidity or sodium, and exposure from ultraviolet rays. In order to study the electrical properties of silicone gels often used as packing material due to the curing condition, volume resistivity and AC breakdown experiment are performed. Specimens are made up at several cured times and temperatures condition ; 0.5[H], 1[H] and 2[H] at 100[$^{\circ}C$], 125[$^{\circ}C$], 150[$^{\circ}C$], 160[$^{\circ}C$], 170[$^{\circ}C$] and 180[$^{\circ}C$]. It is confirmed that from volume resistivity experiment liquid silicone become get state at 90~100 [$^{\circ}C$] and cured specimen for 1~2[H] at 170[$^{\circ}C$] are superior in electrical properties.

• Journal of Environmental Science International
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• v.12 no.4
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• pp.503-510
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• 2003

How to plan the energy system is one of the keys f3r constructing the Environment -Friendly City. for this reason, a great number of surveys for utilizing unused energy have conducted by a planner. In regard to unused energy, the heat from incineration plants classify as a unused energy having high-exergy-energy. From this point of view, It is studied about the plant systems providing heat to district heating & cooling(D.H.C) and producing electric power. It is divided four system models as system I (10K [kgf/cm$^2$) vapor as outlet of boiler, supply far 10K vapor and return to 60$^{\circ}C$ as supply condition of district heating), system II (30 K vapor as outlet of boiler, supply for 5t vapor and return to 60f as supply condition of district heating), system 111 (30 K vapor as outlet of boiler, supply for 85$^{\circ}C$ hot water and return to 60$^{\circ}C$ as supply condition of district heating), system IV (30 K vapor as outlet of boiler, supply for 47$^{\circ}C$ hot water and return to 40t as supply condition of district heating). The results from the upper condition of four system, System II got a proper on economical benefits and system IV calculated as benefiting on energy saving effects, and suggest indifference curve as the total evaluation method of both economical benefits and energy saving.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.8
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• pp.541-546
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• 2014

Korea Expressway Corporation established standard of LED lighting fixture in Dec. 2013. To raise compatibility, the standard requires a fixed form and it is applied to street lights and tunnel lights, etc. Because streetlight has different circumstance condition from tunnel light that is down light and exposed to constant wind velocity over height of 8 meters, in case of LED module which has the same shape, characteristic of radiant heat can be different. In this paper, we designed 25 [W] LED Module that is designated by standard of Korea Expressway Corporation and analyzed characteristics of radiant heat about natural convection and forced convection. It is dropped 10.12[$^{\circ}C$] that max temperature is decreased by increasing 20 mm of bended height of heatsink at the condition of natural convection. Radiant heat characteristic of bended height 35 mm became 78.08[$^{\circ}C$] at the condition of natural convection, 55.30[$^{\circ}C$] at the condition of forced convection so that 22.78[$^{\circ}C$] is decreased that is 29.1[%] decrease. Bended height 55mm became 67.96[$^{\circ}C$] at the condition of natural convection, 48.04[$^{\circ}C$] at the condition of forced convection so that 19.92[$^{\circ}C$] is decreased that is 29.3% decrease.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.10a
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• pp.131-137
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• 1996

To perform condition monitoring of P.C. Box girder bridge under ambient traffic, dynamic characteristics were identified using the results of load test an analysis. It was found that natural frequencies obtained from the measured acceleration data for the forced vibration part and free vibration part were nearly identical. Thus it can be concluded that dynamic parameters are properly determined under ambient traffic condition. Finite element model for analysis was calibrated using measured frequencies. Change of dynamic characteristics were predicted through analysis of the established finite element model with anticipated change.

• Journal of the Chungcheong Mathematical Society
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• v.25 no.2
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• pp.235-239
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• 2012

Let $f$ be an Axiom A difeomorphism of a closed 2- dimensional smooth manifold M: We show that $f$ has the limit shadowing property if and only if $f$ satisfies the $C^0$ transversality condition.

• Journal of the Korean Society for Heat Treatment
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• v.30 no.2
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• pp.43-52
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• 2017

Heat treatment condition for dissolution of the M23C6 carbides in 2.25Cr-1Mo-V-Ti material for thermal power plant tube was investigated using a dilatometer method. 2.25Cr-1Mo-V-Ti material was heat-treated at $900{\sim}1,100^{\circ}C$ for 0, 10, 30 min to find the proper dissolution condition of M23C6 carbides. The phase identification and volume fraction of the carbide were measured by using OM, SEM, EBSD and TEM analysis. Optimal heat treatment condition of M23C6 carbide dissolution was selected by predicting dissolution temperature of carbide using Bs points appeared at dilatometer curve. Experimental results showed that the conditions of carbide dissolution was 900, 1,000, $1,100^{\circ}C$ for 30 min. Eventually, the optimal heat treatment condition for dissolution was 30 min at $1,000^{\circ}C$ considering the minimum coarsening of Austenite grain size.

• KSBB Journal
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• v.4 no.2
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• pp.65-68
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• 1989

In order to determin the optimum extraction condition for protein in a Chrysalis of Silk Worm, Temperature, Time, and pH variation were conducted in the extraction. N.S.I. and nitrogen contents of the extracts in this condition were identified by Kjeldaha method and a C.H.N. corder. The results were as follows; Crude protein and crude fat contents in the extracts were 23.34% and 15.61%, respectively. N.S.I. values with respect to the temperature variation were 6.7% at 6$0^{\circ}C$, 7.94% at 8$0^{\circ}C$ and 8.67% at 10$0^{\circ}C$ in the condition of pH 4, 1 hr. N.S.I. values in pH variation were 7.94% at pH4, 8.99% at pH6, 9.70% at pH8, 10.19% at pH 10 and 12.16% at pH 12 in the condition of 8$0^{\circ}C$, 1hr. N.S.I. values in extraction time variation were 8.67% in 1hr, 9.23% in 2hr and 9.76% in 3hr in the condition of 10$0^{\circ}C$, pH 4. The tendency of N.S.I. variation in this extration condition was reconfirmed also by a C.H.N. corder.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.11
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• pp.895-900
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• 2005

We derive a linear matrix inequality(LMI) condition guaranteeing that any invariant zeros of a triple (A, B, C) lie in the open left half plane of the complex plane, i.e. $C(sI-A)^{-1}B$ is minimum phase. The LMI condition is equivalent to a certain constrained Lyapunov matrix equation which can be found in many results relating to stability analysis or control design. We show that the LMI condition can be used to simplify various control engineering problems such as a dynamic output feedback control problem, a variable structure static output feedback control problem, and a nonlinear system observer design problem. Finally, we give some numerical examples.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.103-106
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• 2000

Nondestructive tests are useful method in rapidly evaluating the condition of existing concrete structures. An objective of this work is to investigate the factors influencing the longitudinal wave velocity-strength relationship, such as w/c ratio, curing temperature, curing condition. Test results show that a change in the w/c ratio ranging from 0.46 to 0.88 and in the curing temperature from 1$0^{\circ}C$ to 3$0^{\circ}C$ did not alter the velocity-strength relationship. however, curing methods had significant effects on the velocity-strength relationship. Therefore, the estimation of compressive strength until 28 day can be accomplished by only a nonlinear equation with consideration of curing condition.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.59-59
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• 2000

Recently low resistance of bus line is required for large screen size TFT-LCD panels. As a result, lower resistance Al-alloy is currently reviewed extensively. The resistivity is required smaller than 10 $\mu$$\Omega$cm. In this paper, Al-Nd thin film were deposited on glass substrates by D.C. magnetron sputtering system under various condition. Its properties were characterized by SEM, AFM, XRD, 4-ping-probe. The optimal condition of Al-Nd was 12$0^{\circ}C$, 125W, 0.4Pa, 30sccm(Ar) and 35$0^{\circ}C$, 20min. annealing. At that condition the resistivity of Al-Nd(2wt.%) was about 4 $\mu$$\Omega$cm. The minimum contact resistance of ITO/Nd was about 110$\mu$$\Omega$cm in the condition of 30$0^{\circ}C$, Ar 30 sccm. O2.