• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.6
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• pp.965-970
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• 1994

ZnO transparent conducting oxide thin films have been prepared by Pyrosol deposition method and the effects of the different experimental variables on the electrical resistivity and optical transmittance of the prepared films have been investigated in details. The best film with a resistivity of about 8 X 10S0-2TΩcm and transmittance about 80% has been obtained at the substrate temperature of 4$25^{\circ}C$ by using HS12T+CHS13TOH(1:3) solvent and NS12T carrier gas after annealing at 20$0^{\circ}C$ for 40 minutes in vacuum. Furthermore, We have also found the effect of substrate temperature on crystallographic orientation and surface morphology. Annealing of the as-deposited film in vacuum leads to a substantial reduction in resistivity without affecting the optical transmittance and crystallographic orientation.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.123-126
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• 1995

The purpose of this paper is to improve ultrasound images using motion estimation and recursive filtering. Although averaging without motion correction can make image blurring, the proposed estimation method improves image SNR without motion blurring by recursively averaging images with motion correction. Computer simulation on the proposed method has been performed to improve phantom and ultrasound fish images and the results show the utility of the proposed method.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1506-1509
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• 2000

The Korean National Photovoltaic Project was initiated in October 1989 to develop technologies for the generation of economically competitive electric power by photovoltaic systems. It consists of four stages through the year 2006 with technical goals and cost targets related with solar cells, balance of systems and system application. The objectives of the project are to utilize photovoltaic technology, to transfer developed technology to industries and end users by research activities and to diffuse photovoltaic systems by demonstration projects. This paper reviews long-term plan abd status of technology R&D, and markets of photovoltaics. Some activities designed to promote collaboration with foreign countries are also introduced.

• Corrosion Science and Technology
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• v.10 no.2
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• pp.65-70
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• 2011

DLC is considered as the candidate material for application of moving parts in automotive components relatively in high pressure and temperature operating conditions for its high hardness with self lubrication and chemical inertness. The properties of interlayer between the substrate and the DLC film were studied. Arc ion plating method have been employed to deposit onto substrate and sputtering method was used for synthesizing DLC onto interlayer. Among these six types of interlayer, deposited DLC film onto TiCN showed excellent value for characteristics. From the results of analysis for physical properties of DLC films, it seems that the adhesion forces were more important factors than intrinsic mechanical properties such as hardness, roughness and wear resistance of DLC films. AFM(Atomic Force Microscope) was used for understanding roughness of DLC films. Hardnesses of the coating layers were identified by nano-indentation method and adhesions were checked by scratch method.

• Journal of the Korean Ceramic Society
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• v.26 no.3
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• pp.409-415
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• 1989

Si3N4-TiN electro-conductive ceramic composites with 7wt% Al2O3＋3wt% Y2O3 or 5wt% MgO as sintering aids were fabricated by pressureless sintering at 1,80$0^{\circ}C$ for 1h. The 3pt. flexural strength, KIC and Vickers hardness were measrued in order to investigate the effects of TiN on the mechanical properties. Also oxidation behavior was observed by measuring the weight gain after exposure to air at 1,10$0^{\circ}C$ for 100h. the reaction products between Si3N4 and TiN was not detected by XRD and EDS. Mechanical properties of the composites were not influenced by the addition of TiN less than 30vol%, but oxidation resistance of the composites was rapidly decreased with the amount of added TiN.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.326-328
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• 1996

The 10kW or 1MW model of a photovoltaic array written in PSPICE is presented in this paper. A problem with this large scale centralized photovoltaic system is the decrease of power due to the resistance of cable connecting individual subarray with inverter. In this paper, we analyzed the relationship between the resistance of cable and subarray output power of 1MW photovoltaic system by the PSPICE modeling. As a result of simulation, we can proved that photovoltaic array output power is limitted by the resistance of cable.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.31-35
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• 2002

스위치드 릴럭턴스 모터의 연구에서 센서리스 구동방법이나 이와 유사한 구동 방법은 스위치드 릴럭턴스 모터의 상품화 및 상용화에 있어서 소음 문제와 함께 반드시 해결해야 할 문제이다. 그러나 센서리스 구동 방법들은 초기 구동에 있어서 강제정렬 방법을 사용한 것이 일반적인데, 이것은 모터의 사용에 있어서 제한성을 가져다 준다. 본 논문에서는 탐색 코일을 이용한 스위치드 릴럭턴스 모터의 구동법과 함께 강제 정렬의 방법을 사용하지 않고 초기 기동문제를 해결하는 방법을 제안하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.2 no.4
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• pp.11-18
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• 1997

태양광 발전시스템의 발전출력은 일사량과 온도에 따라서 크게 변동하고, 태양전지 어레이와 병렬로 연결되는 축전지의 전압에 의해 변동한다. 이 대책으로 지금까지 MPPT 제어(최대출력점 제어)를 해왔는데, 이 제어방식은 손실이 크고 비용이 많이 든다. 따라서 본 논문에서는 이러한 PV 시스템 구성요소의 매칭 손실저감을 위하여 PSpice를 이용한 구성요소의 전자 모델링을 행하고, 태양전지 어레이와 축전지 및 인버터 입력전압의 최적 전압구성법에 대한 연구 결과에 대하여 기술하고 있다. 축전지 최적전압은 태양전지 어레이 최적전압의 약 90%정도가 적당하다는 결과를 얻었다.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.125-129
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• 2006

This paper presents the isolation and performance evaluation of PV systems installed at Tibet area of China in order to identity the key factors that determines system operation at a severe climate conditions and promote the cooperation of PV technology between Korea and China. The installed systems consist of 100kW on-grid connected PV systems, BOS(balance of systems), data acquisition and transmission equipments. The Korea side supplied the solar cell, BOS like as inverter, control box and monitoring system. And the Chinese side assembled solar module by using Koreans solar cells, constructed site and built control house.

• Bulletin of the Korean Chemical Society
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• v.17 no.12
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• pp.1149-1153
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• 1996

Ab initio and extended Huckel calculations were carried out on the isomers of trans-RhCl(η2-C2H2)(PH3)2 (1). Due to π-back donation in 1 complex, the rotational energy barrier of alkyne ligand is computed to be in the range of 18.6-25.2 kcal/mol at MP4 levels. The optimized hydrido-alkynyl complex (2) at ab initio level has the distorted trigonal bipyramidal structure. Vinylidene complex (3) is computed to be more stable than 1 complex by 17.1 kcal/mol at MP4//MP2 level. The stabilities of isomers show similar trend at the various level calculations, that is, EHT, MP4//HF, and MP4//MP2 levels. The optimized geometries at ab initio level are in reasonable agreement with experimental data. A detailed account of the bonding in each isomers (1-3) have been carried out in terms of orbital analyses.