• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.365-366
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• 2015

This paper describes the analysis on thermo-mechanical characteristics of underground cable termination. Specially, the interface pressures between stress relief cone and XLPE insulation were analysed according to the change of conductor temperature and ambient temperature. This interface pressures were measured by real test with current transformer and chamber and the interface pressure was changed with conductor and ambient temperature. This paper will continue to perform the test with various cases, then the relation between low interface pressure and breakdown will prove with test results in the near future.

• Smart Structures and Systems
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• v.19 no.4
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• pp.403-413
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• 2017

The present article encompasses a nonlinear finite element (FE) and genetic algorithm (GA) based optimal vibration energy harvesting from nonprismatic piezo-laminated cantilever beams. Three cases of cross section profiles (such as linear, parabolic and cubic) are modelled to analyse the geometric nonlinear effects on the output responses such as displacement, voltage, and power. The simultaneous effects of taper ratios (such as breadth and height taper) on the output power are also studied. The FE based nonlinear dynamic equation of motion has been solved by an implicit integration method (i.e., Newmark method in conjunction with the Newton-Raphson method). Besides this, a real coded GA based constrained optimization scheme has also been proposed to determine the best set of design variables for optimal harvesting of power within the safe limits of beam stress and PZT breakdown voltage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11b
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• pp.19-22
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• 2004

Growth of Electrical Tree Under 50Hz~60Hz high electric stress has been studied on the Occurrence of a Pattern, to the Progression Speed at Y axis of electrical Tree. CCD Images of evolving tree structures could be obtained in both systems. Electrical Treeing was found to occur reproducibly, but in a markedly different manner in the two morphologimlly different but chemically identical materials. For the measurement of Electrical Tree, a visual measurement with an optical microscope has been used to explain breakdown mechanism in High-voltage systems.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1794-1797
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• 1997

The preflashover light emission of the $SiO_2$-dielectric system behavior under high electric field is discussed. Time dependence of the voltage drop, electrical current, and light emission, are analyzed for high-purity $SiO_2$-vacuum systems under impulse voltage stress. We will summarize the experimental results showing the main feature of the time-dependent system response up to breakdown.

• Structural Engineering and Mechanics
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• v.60 no.2
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• pp.301-312
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• 2016

In a concrete member under pure tension, the stress in concrete is uniformly distributed over the whole concrete section. It is supposed that a local bond failure occurs at each crack, and there is a relative slip between steel and surrounding concrete. The compatibility of deformation between the concrete and reinforcement is thus not maintained. The bond transfer length is a length of reinforcement adjacent to the crack where the compatibility of strain between the steel and concrete is not maintained because of partially bond breakdown and slip. It is an empirical measure of the bond characteristics of the reinforcement, incorporating bar diameter and surface characteristics such as texture. Based on results from a series of previously conducted long-term tests on eight restrained reinforced concrete slab specimens and material properties including creep and shrinkage of two concrete batches, the ratio of final bond transfer length after all shrinkage cracking, to THE initial bond transfer length is presented.

• Corrosion Science and Technology
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• v.15 no.4
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• pp.153-158
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• 2016

Light metal alloys of Mg, Ti, and Al undergo environmentally assisted cracking (EAC). Passive film breakdown and pitting are not only precursor events for stress corrosion, but can accelerate hydrogen evolution that is responsible for hydrogen embrittlement. This is clearly demonstrated in the case of Mg and Ti alloys. The so-called innocuous precipitates, which do not directly participate in either alloy strengthening or EAC can be effective precursors for initiating EAC. This aspect is highlighted using high strength aluminium alloys. Such behaviours lead to a paradigm shift in the design of alloys with resistance to EAC.

• The Journal of Pediatrics of Korean Medicine
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• v.13 no.1
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• pp.1-16
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• 1999

A literature study was progressed for oriental medical diagnosis and treatment for Jianwang(健忘) : forgetfulness(amnesia). In orental medicine, the reason of Jianwang(健忘) was congenital insufficiency(稟賦不足), meditational excessiveness(思慮過多), deficiency of heart(心虛), phlegm retention(痰飮), deficiency of kidney(腎裏), breakdown of the normal physiological coordination between the heart and the kidney(心腎不交), blood stasis(瘀血). The method of medical treatment was invigorating vital energy and enriching the blood(大補氣血), invigorating the heart and nourishing blood(補心養血), dissipating phlegm and relieving mental stress(化痰寧神), regulating the spleen corresponds to earth(理脾土), invigorating the heart and the kidney(補心腎), reinforcing the liver and the kidney(培肝腎), promoting blood circulation to remove blood stasis(活血祛瘀) and etc. Herbal medication was followed as those method. The prescription was commonly used as Guibitang(歸脾湯), Insuksan(仁熟散), Chunwangbosimdan(天王補心丹), Susunghwan(壽星丸), Samjohwan(蔘棗丸) and etc.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.6
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• pp.107-116
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• 1994

In this paper, The electrical properties of MOS capacitors and transistoras with gate of in-situ doped amorphous Si and poly Si doped by POCI$_3$. Under constant current F-N stress, MOS capacitors with in-situ doped amorphous Si gate have shown the best resistance to degradation in reliabilty properties such as increase of leakage current, shift of gate voltage (V$_{g}$). shift of flat band voltage (V$_{fb}$) and charge to breakdown(Q$_{bd}$). Also, MOSFETs with in-situ doped amorphous Si gate have shown to have less degradation in transistor properties such as threshold voltage, transconductance and drain current. These improvements observed in MOS devices with in-situ doped amorphous Si gate is attributed to less local thinning spots at the gate/SiO$_2$ interface, caused by the large grain size and the smoothness of the surface at the gate/SiO$_2$ interface.

• Transactions on Electrical and Electronic Materials
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• v.16 no.3
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• pp.107-111
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• 2015

Our work is based on the development of a numerical model to develop a methodology for predicting the aging and breakdown in insulation due to the dynamics of space charge packets. The model of bipolar charge transports is proposed to simulate space charge dynamic for high DC voltage in law-density polyethylene (LDPE), taking into account the trapping and detrapping of recombination phenomena, this model has been developed and experimentally validation. Theoretical formulation of the physical problem is based on the Poisson, the continuity and the transport equations as well as on the appropriate models for injection. Numerical results provide temporal and local distributions of the electric field, the space charge density for the different kinds of charges, conduction and displacement current densities, and the external current.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.497-501
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• 2004

The primary failure causes of underground distribution power cables are water penetration in insulation layer and stress enhancement at inner semi-conductive layer. Accordingly, it is needed to improve the materials and the structure of power cables for extending lifetime and preventing failure. We uses non-flaming PE materials instead of PVC as a covering material and encapsulating structure. We also use super smooth class material as a inner semi-conductive layer. The newly developed cables are improved in AC breakdown voltage after ageing tests.