• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.135-137
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• 2002

In the favor of adjusting microwave signal, Hairpin type Filter, which delay microwave signal enough to several nanosecond, is a key component. One of the main advantage in using Hairpin type Filter is a conveniency for equipping with Delay Module, and because of having a wide bandwidth, Hairpin type Filter can be designed to satisfy the most applications. In this work, we attempted to estimate the delay time in a superconductive hairpin type filter A software to synthesize even and odd order equiripple hairpin type filter has been developed. This software arbitrarily locate its transfer zeros making symmetric of asymmetric amplitude response and equalizing group delay. Borland C++ compiler has been used. The program was designed to run under MS-DOS, Window 98, Window 2000. The program optimizes the position of the transfer function zeros in order to fulfill the group delay specification masks. We designed and fabricated a hairpin type HTS 2-pole microstrip bandpass filter to operate at 5.8Ghz. The fabrication method was pulsed laser deposition and YBCO films were deposited on sapphire substrates with a Ce$O_{2}$ thin layer as a buffer layer. We also developed a new style hairpin type filter by using interdigitide inner-pole. Compared to the same size regular hairpin type filters, our filters had a lower center frequency.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1853-1857
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• 2005

This paper reports on the development of the gripping system for automation of phone-camera module assembling. If manual assembling is shifted by automation, it will increase the fabrication speed and reduce the defective rate. In the gripping mechanism design, we needs self-adjustable passive mechanism that minimize the number of the parts. The self-adjusting system compensates the positioning errors that have been made in translations. And also we need gripper system that can be modules of parts. That makes it easy to change or repair the parts. The forces put on the objects is another considerable in the system. It must not cause dropping, breakage, scratch, and large deformation. So final target of this reaseach is how to develop the system that is speedy, small, simple, and safe

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.10
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• pp.1333-1340
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• 2002

The objective of this study is to develop a thermoelectric generation system which converts unused energy from close-at-hand sources such as garbage incineration heat and industrial exhaust etc. into electricity. This paper presents applicability of a commercially available thermoelectric generator f3r waster heat recovery. The test facility consists of water heater, pump, thermoelectric module and aluminium tubes and hot and cold water is used as heat source and sink fluids. It is shown that the three components of thermoelectric research exist in manufacturing a thermoelectric generator. The first component is fabrication of thermoelectric materials, the second is manufacturing of thermoelectric generator with 32 thermoelectric modules. The last one is characteristic measuring of thermoelectric generator with 32 thermoelectric modules of two types, cooling and power purpose. It was found that the rate of cold and hot water is 25 and 37 liter per minute and the maximum power of thermoelectric generator is 28Watts and its efficiency is 1.04%.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.14 no.1
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• pp.24-31
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• 2018

The mechanical design procedure is studied for the PCHE(printed circuit heat exchanger) with electrochemical etched flow channels. The effective heat transfer plates of PCHE are assembled by diffusion bonding to make a module. PCHE is widely used for industrial applications due to its compactness, cost efficiency, and serviceability at high pressure and/or temperature conditions. The limitations and technical barriers of PCHE are investigated for application to nuclear components. Rules for design and fabrication of PCHE are specified in ASME Section VIII but not in ASME Section III of nuclear components. Therefore, the calculation procedure of key dimensions of PCHE is defined based on ASME section VIII. The effective heat transfer region of PCHE is defined by several key dimensions such as the flow channel radius, edge width, wall thickness, and ridge width. The mechanical design procedure of key dimensions was incorporated into a program for easy use in the PCHE design. The effect of assumptions used in the key dimension calculation on stress values is numerically investigated. A comparative analysis is done by comparing finite element analysis results for the semi-circular flow channels with the formula based sizing calculation assuming rectangular cross sections.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.5
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• pp.639-642
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• 2013

In this paper, proposed NED(nuclear event detectors) for detection of a transient radiation. Nuclear event detector was blocked of power temporary for defence of critical damage at a electric device when a induced transient radiation. Conventional NED consist of BJT, resistors and capacitors. The NED supply voltage of 5V and MCM(Multi Chip Module) structures. The proposed NED were designed for low supply voltage using 0.18um CMOS process. The response time of proposed NED was 34.8ns. In addition, pulse radiation experiments using a electron beam accelerator, the output signal has occurred.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.12
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• pp.37-43
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• 2012

UV-IR diagnostic technology is being used for predictive maintenance of high voltage equipment together with IR-thermography and ultrasonic devices. In this paper, the UV-IR camera design, fabrication, and perform a simple test to be take advantage of the diagnostic equipment. UV-IR camera developed a $6.4^{\circ}{\times}4.8^{\circ}$ of the field of view as a conventional camera to diagnose a wide range of slightly enlarged, and power equipment to measure the distance between the camera and the distance meter has been attached. In a distance of 5m with the UV-IR it is possible to detect partial discharge with a PD level of 2.5 pC and a RIV(Radio Influence Voltage) level of $3.6dB{\mu}V$.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.26-26
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• 2003

During fabrication process for the large space optical surfaces, the traditional bound abrasive grinding with bronze bond cupped diamond wheel tools leaves the machine marks and the subsurface damage to be removed by subsequent loose abrasive lapping. We explored a new grinding technique for efficient quantitative control of precision CNC grinding for space optics materials such as Zerodur. The facility used is a NANOFORM-600 diamond turning machine with a custom grinding module and a range of resin bond diamond tools. The machining parameters such as grit number, tool rotation speed, work-piece rotation speed, depth of cut and feed rate were altered while grinding the work-piece surfaces of 20-100 mm in diameter. The input grinding variables and the resulting surface quality data were used to build grinding prediction models using empirical and multi-variable regression analysis methods. The effectiveness of the grinding prediction model was then examined by running a series of precision CNC grinding operation with a set of controlled input variables and predicted output surface quality indicators. The experiment details, the results and implications are presented.

• Transactions on Electrical and Electronic Materials
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• v.4 no.4
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• pp.22-25
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• 2003

High series resistance due to the presence of glass frit is one of the major problems for screen printed silicon solar cells. Cells having electrical parameters below the prescribed values are usually rejected during solar module fabrication. Therefore, it is highly desirable to improve the electrical parameters of the silicon solar cells and thereby to increase the overall production yield. It was observed that, the performance of low quality mono-crystalline silicon solar cells made by standard screen printing technology could be improved remarkably by novel surface treatment. We have chemically treated the surface using sodium hydroxide (NaOH) and silver nitrate ($AgNO_3$) solutions. NaOH treatment helps to reduce the series resistance by decreasing the presence of excess glass frit on the top silver grid contact. The $AgNO_3$ treatment is used to reduce the series resistance comes from the deposition of silver on the grids by filling the holes present (if any) within the grid pattern.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.450-451
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• 2006

The method of conductor wiring is that a messenger wire is installed, the end of the wire is connected to the conductor and a engine puller pulls the conductor. The length of one section of wiring is $3{\sim}5km$ and one group messenger wire pulls simultaneously $2{\sim}4$ group conductor, while a tensioner maintains wiring tension to prevent the deflection of the conductor. However, there are many obstacles such as roads, power lines, communication lines, buildings, farms and crops. Therefore to prevent damage from conductor deflection a staging is used. The currently used staging is scaffolding lumber which is difficult to secure and it's construction efficiency is very low because it requires a lot of time and manpower. So this study developed a insulating defense tube and pipe connecting device, and a truss structure fabrication module using steel pipe which reduces construction time and cost through a compressive and dielectric strength test.

• Korean Journal of Optics and Photonics
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• v.19 no.2
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• pp.140-143
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• 2008

The integrated external cavity laser has been fabricated with a 1550 nm FP-LD, an optical filter, a micro ball lens and accurate ceramic blocks using a micro-block stacking (MBS) technique. The integrated external cavity laser module whose size is only $2.0{\times}2.1{\times}0.7\;mm^3$ has been mounted on the TO-CAN package. For the case of the 1.8% transmission filter, the single mode characteristic has been obtained with the optical power of -27.1 dBm and the SMSR of 31.7 dB.