• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.4
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• pp.322-327
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• 2006

CdS films have been prepared on polycarbonate, polyethylene terephthalate, and Coming 7059 substrates by r.f magnetron sputtering technique at room temperature. A comparison of the properties of the films deposited on polymer and glass substrates was performed. In addition, the influence of the sputter power on the structural and optical properties of these films was evaluated. The XRD measurements revealed that CdS films were polycrystalline and retained the mixed structure of hexagonal wurtzite and cubic phase, regardless of substrate types. As the sputter power was increased from 75 to 150 Watt, the structure of CdS films was converted from the mixed of hexagonal and cubic phase to hexagonal phase. The morphology of CdS films is found to be continuous and dense. Also, the grain of CdS films is larger with increasing the sputter power. The average transmittance exceeded 80 % in the visible spectrum for all films and decreases slightly with the sputter power.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.830-832
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• 1999

청주 LG산전 전력시험기술센터에는 LG산전에서 생산하고 있는 모든 전력량계를 관련규격에 따라 자동으로 시험할 수 있는 분리형 펄스 장치[1]와, 전력량계 회전 감지용 센서 및 카운터, 측정용 소프트웨어를 보유하고 있다. 기존 소프트웨어는 개발 당시 등록한 모든 전력량계에 한해서 관련규격에 따라 자동으로 시험하고 각 전력량계에 대한 개별 오차와 평균 오차, 개별오차와 평균오차와의 차이를 계산하고, 계산결과를 출력할 수 있는 기능들을 지니고 있었다. 그러나 기존 소프트웨어에는 새로운 시험환경을 등록할 수 있는 기능이 없었다. 따라서 G산전에서 생산되는 전력량계가 다양화됨에 따라 새로운 전력량계도 시험할 수 있도록 기존 소프트웨어를 수정하지 않을 수 없었다. 이러한 문제로 인해 LG산전에서는 기존 소프트웨어가 가지고 있는 문제점을 해결하고 데이터 관리 및 성적서 작성 기능과 같은 새로운 기능을 가진 소프트웨어를 개발하게 되었다. 따라서, 본 논문에서는 측정용 소프트웨어 개발 과정과 새로운 기능들 현장 적용 결과를 발표하고자 한다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.4
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• pp.282-290
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• 2003

AMR(Automatic Meter Reading) and RC(Remote Control) System have been researched from former several decade for a various power rate system, a efficient power service and rising of personal expenses, etc. But the existing AMR and RC System have disadvantage which are complex and high cost to install an individual communication network of electricity company. This paper proposed a new type of AMR and RC System using PLC with Web. and made components for proposal system. Most customer who live in apartment have an internet cable in the Republic of Korea. Therefore there is no more installation component for communication in proposal system at the apartment, except Web server system and PLC modem. so we made the PLC modem the digital watt-hour meter with a build in PLC modem and the software on server computer for establishing the proposal system.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.4
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• pp.446-451
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• 2009

In this paper, we described the design and test results of a high output power amplifier MMIC developed by using 0.5um power pHEMT processes on a 6-inch GaAs wafer for the X-band T/R module application. In the MMIC design, we have used a simple on-chip gate active bias technology to compensate the threshold-voltage variation of pHEMT during the fabrication process and 16-to-1 power combining method to achieve the output power over 10watt. The fabricated chip has an output power over 12watts and maximum PAE of 32% over the frequency range of fo +/-750MHz.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.5
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• pp.475-483
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• 2000

This paper describes designs about the power system of KITSAT-4 satellite. The KITSAT-4 power system is mainly composed of power stage and control stage. The power stage is a 200〔W〕 buck converter and control stages are hardware controller and software controller The hardware controller is PPT(Peak Power Tracker), battery voltage controller and software controller is battery current controller and direct duty controller. So the operation of power system has many advantages in that it can select controller according to reliable control and precise control. The controller design methods are presented and the small signal analyses are performed to verify system stability.

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.1
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• pp.8-16
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• 2003

$TiO_2$ thin films were deposited by DC reactive magnetron sputtering with variations in sputtering parameter such as Ar and $O_2$ flow rate, DC power, substrate temperature and magnetic field. Deposition rate, crystal structure, chemical bond of $TiO_2$ films on the deposition conditions were investigated by Alpha-step, X-ray Diffractometer(XRD), X-ray Photoelectron Spectroscopy(XPS). When the DC power was applied at 500watt, deposition rate of $TiO_2$ film was about 480A/min. $TiO_2$ films coated under the deposition condition of 15sccm Ar and 7~10sccm $O_2$ flow rate was only observed anatase phase. With increasing substrate temperature from RT to $300^{\circ}C$, crystal orientation of $TiO_2$ films variously became.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.28-28
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• 2008

Generally speaking, Rogowskii coil for magnetic flux change detection according to electric current is used for digital addition watt-hour meter, because it is not saturated at electromagnetic that not Current Transformer working by magnetic material but non-magnetic material. In this paper, we described sensitive quality an electric current coil sensor followed by the principal of Rogowskii coil on the low dielectric loss LTCC, change different line width, gap, line length at sensing parts and extinction parts.

• Journal of the Korean Institute of Telematics and Electronics
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• v.14 no.5
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• pp.7-14
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• 1977

Conventionally, a TIVT has been used for high power amplification in the microwave frequency range. However, an ultra-high-power amplifier in the 2GHz range has successfully been designed and fabricated employing high power transistors developed recently and available commercially. In the design of the amplifier, a balanced-pair configuration is adopted in order to obtain very high microwave power, and a good impedance matching is achieved by making use of microstripline techniques. For the RF power divider as well as combiner, an approach of stripline directional coupler isadopted because of its easiness in fabrication. The coupler so designed and fabricated indicates a satisfactory performance as a quadrature hybrie coupler. Measurements on the amplifier developed for an immediate commercial application also exhibit excellent overall performance characteristics RF power output, 14 watts, gain 14dB, frequency bandwidth, 160MHz, effciency 40%.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.104-108
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• 2012

Recently, small scale hydropower needs to be developed due to its clean, renewable and abundant energy resources. However, suitable draft of hydro-turbine body in combination with differences in wheel blade shapes is not determined yet in the range of small hydropower and it is necessary to study for the effective draft in combination with type. Therefore, watermill shaped of 250mm diameter. hydro-turbine aiming 20 watt class generator is adopted in this study because of its simple structure and high possibility of applying to small hydropower. The result shows that effective draft for the turbine body is variable concerning the size of turbine and flow rate of water. Thus, the difference of water depth between fore and aft turbine body contributes to the increase of torque, angular momentum and power output.

• Journal of ILASS-Korea
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• v.5 no.1
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• pp.49-57
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• 2000

This study presents the flow visualization results, velocity and turbulence intensity measurements made within an air filter cover and entry region of a mass air flow sensor (MAFS) which is used in an induction system of 3.8L engine. Flow structure in two air filter cover assemblies were examined. The first was a clear plastic replica of the production cover while the second was a modified clear plastic cover with a geometry configured to reduce fluctuations. High speed flow visualization and laser doppler velocimetry (LDV) systems were used to reveal and analyze the flow field characteristics encountered in the sensor design process under steady flow conditions. A 40-watt copper vapor laser was used as a light source. Its beam is focused down to a sheet of light approximately 1.5mm thick. The light scattered off the particles was recorded by a 16mm high speed rotating prism camera at 5000 frames per second. A comparison of the flow patterns and LDV measurements in the original and modified air filter covers is presented to illustrate the controlling effect of the cover design on the turbulence structure formation near the bypass and on the sensor output signal. In both axial and radial planes of the main passage it was found that the turbulence flow pattern is remarkably influenced by the air filter cover and main passage configuration.