• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.526-530
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• 2004

We report the space charge and the surface potential of the interface between metal and CuPc according to isotropic property and different metal by measuring the microwave reflection coefficients $S_{11}$ of copper(II)-phthalocyanine(CuPc) thin films by using a near-field microwave microscope(NSMM) in order to understand. CuPc thin films were prepared on gold and aluminium substrates using a thermal evaporation method. Two kinds of CuPc thin films were prepared. One was deposited on preheated substrate at $150^{\circ}C$ and the other was annealed after deposition by using thermal evaporation methods. The microwave reflection coefficients $S_{11}$ of CuPc thin films were changed by the dependence on the heat treatment conditions. By comparing reflection coefficient $S_{11}$ we measured electrical conductivity of CuPc thin films and studied this results with respect to the surface potential and space charge of the interface between metal and CuPc thin films.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.292-297
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• 2000

In this research, the dynamic photoelastic experimental hybrid method for bimaterial is introduced. Dynamic biaxial loading device is developed, its strain rate is 31.637 s-1 and its maximum impact load is 20 ton. Manufactured methods for model of the dynamic photoelastic experiment for bimaterial are suggested. They are bonding method(bonding material: AW106, PC-1) and molding method. In the bonding method, residual stress is not occurred in the manufactured bimaterial. Crack is propagated along the interface or sometimes deviated from the interface. While in the molding method, residual stress is occurred in the manufactured bimaterial. Crack is always deviated from the interface and propagated in the epoxy region(softer materila). In order to propagate with constant velocity along the interface of bimaterial with arbitrary stiffer material, edge crack should be located along the interface of the acute angle side of the softer material in the bimaterial.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.439-442
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• 2002

The interface between two different materials in the insulation systems is the weak-link in the underground power transmission systems, In this paper, Optimum conditions of the interface between Epoxy and EPDM is studied. The variation factor condition of interface is roughness of surface, spreading of oils, interfacial pressure and temperature. The breakdown times under the constant voltage below the breakdown voltage were also gained. The breakdown voltage at the after laying time equivalent to is calculated by the V-t characteristic and the inverse power law. When this is done, the characteristic life exponent n is used and the long time breakdown voltage can be evaluated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.95-96
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• 2005

The general method and mechanism for the polarity control of heteroepitaxial wurtzite films, such as ZnO and GaN, by interface engineering via plasma-assisted molecular beam epitaxy are addressed. We proposed the principle and method controlling the crystal polarity of ZnO on GaN and GaN on ZnO. The crystal polarity of the lower film was maintained by forming a heterointerfce without any interface layer between the upper and the lower layers. However the crystal polarity could be changed by forming the heterointerface with the interface layer having an inversion center. The principle and method suggested here give us a promising tool to fabricate polarity inverted heterostructures, which applicable to invent novel heterostructures and devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.59-64
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• 1994

The Si-SiO$_2$interface trpas of the degraded short-channel SONOSFET memory devices were investigated using the charge pumping techniques. The degradation of devices with write/erase cycle appeared as the increase of the Si-SiO$_2$interface trap density. In order to determine the capture cross-section of the interface trap. I$\_$CP/-V$\_$GL/ characteristic curves were measured at different temperatures. Also, the spatial distributions of Si-SiO$_2$interface trap were examined by the variable-reverse bias boltage method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.532-535
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• 1999

In power cable joints, the interfaces of two different dielectric materials are inevitable. In addition, the interfacial breakdown between two internal dielectric surfaces represents one of the major causes of failure for power cable joints. We chose epoxy/EPDM interface, one of the interface in cable joints, and investigate dielectric interfacial breakdown phenomenon. First, design specimen with Flux 2D. Second, find interface condition which has high dielectric strength. Third, investigate interfacial breakdown properties with variable temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1988.10a
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• pp.21-26
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• 1988

Composition with O-3 connectivity were fabricated from PZT and phenolic resin powders. These composites were investigated for dielectric and pizoelectric properties with PZT-polymer interface porosity variation. The interface porosity dependence of dielectric and piezoelectric properties was especially discussed by porosity factors. The interface porosity dependence of piezoelectric constant was larger than that of dielectric constant. It was considered that the interface pore plays the role of a stress buffer. Thus the local stress applied on PZT particles in the composite was remarkably diminish.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.7
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• pp.607-611
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• 2000

The characteristics on the interface between Epoxy and EPDM which are materials of the underground insulation systems of power delivery have studied. The breakdown strength of specimens are observed by applying high AC voltage at the room temperature. The breakdown times under the constant voltage below the breakdown voltage were gained. As constant voltage is applied the breakdown time is proportion to the breakdown strength. The life exponent n is gained by inverse power law and the long breakdown life time can be evaluated. AC breakdown strength and life time is improved by oiling to the interface. When the low viscosity oil is spread interface has the highest life time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.93-93
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• 2007

We present a mechanism for stress-induced interface degrdadations through ab initio pseudopotential calculations. We find that N interstitials at the interface create various defects levels in the Si band gap, which range from the mid gap to the conduction band of Si. The level positions are dependent on the configuration of oxygen toms around the N interstitial. On the other hand, the mid-gap level caused by Pb center is possibly removed by substitution of a N atom for a threefold-coordinated Si atom in the defect. Our calculations explain why interface state generations are enhanced in Si oxynitride, especially near conduction band edge of Si, although densities of Pb center are reduced.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.10
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• pp.2089-2095
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• 2002

Ceramic/metal composites have many attractive properties and great potential fur applications. Interfacial fracture properties of different layered composites are important in material integrity. Therefore, evaluation of fracture toughness at interface is required in essence. In this study, the mechanical characteristics for interface of ceramic/metal composites were investigated by indentation test of micro-hardness method. Apparent interfacial toughness of TBC system could be determined with a relation between the applied load and the length of the crack formed at the interface by indentation test.