• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.1
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• pp.85-92
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• 2002

In this study, we analyzed and experimented micro-strip line inductors and capacitors for a SAW duplexer, an important devise for mobile communication. For SAW duplexers, micro-strip line lumped elements must have small impedance values, below several tens of nH or several tens of pF, and a small area pattern. In this study, we performed theoretical analysis of flat line type, meander line type, and spiral line type inductors and interdigital capacitors on a LiTaO$_3$ Piezo-crystal. We proposed a measurement method to evaluate small values of lumped elements accurately with network analyzer. In experiments, we confirmed validity of the theoretical analysis method through fabrication and characterization of micro-strip line lumped elements. The analysis method in this paper can be applied to SAW duplexers well as other microwave devices.

• Current Optics and Photonics
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• v.5 no.3
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• pp.238-242
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• 2021

In this paper, we present an in line plastic-optical-fiber (POF) temperature sensor based on intensity modulation. The in line POF temperature sensor is composed of a POF, including an in-fiber micro hole filled with reversible thermochromic material, the transmittance of which depends on temperature. The reversible thermochromic material was cobalt chloride/polyvinyl butyral gel. A cobalt chloride solution of concentration 30.8 mM was formulated using 10% water/90% ethanol (v/v) solution, and gelled by dissolving polyvinyl butyral in this solution. Four types of in line POF sensors, with in line micro holes of four different diameters, were fabricated to measure temperature in the range of 25 to 75 ℃. The output optical power of all of these in line POF temperature sensors was inversely proportional to the temperature; the relation between output power and temperature was approximately linear, and the sensitivity was proportional to the diameter of the in-fiber micro hole. The experimental results indicate that an in line POF sensor can be used effectively for measuring moderate temperatures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.362-365
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• 1997

In the field of Micro-Mechanics, it has been known diffcult to integrate the micro-machine with sensor and source line for the conventional copper line cnanot be used in compact and small size. We developed a system to make thethin copper film as a connect line on the poyurethane pipe (2mm in diameter) by the evaporation technique. This system consists of an evaporation chamber two long branches, substrate hoider and a Linear-Rotary motion feed feedthrough. The results showed that thin copper film coated polyurethanc pipe could be applied th the small medical devices such as the micro active endoscope.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.143-151
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• 1999

The shape of surface micro-crack is very irregular due to nonhomogeneous microstructure but is very important in respect to qualitative estimation of fatigue life. Fractal geomety can quantify the shape of surface mciro-crack. Fractal dimension is measured for surface micro-cracks with coast line and box counting method and estimates cycle ration in Al 2024-T3. The average fractal dimension $D_{favg}$ of surface micro-cracks has 3-parameter weibull distribution and location parameter is nearly constant but shape parameter decreases as cycle ration increases. The fractal dimension by coast line method is measured for individual surface micro-crack but the fractal dimension by box countin method is measured for all the surface micro-cracks under sampling area. Therefore, This paper shows fractal dimension $D_{fb}$ can predict cycle ratio $N/N_f$ more convenient than fractal dimension $D_{favg}$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.157-158
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• 2007

• Proceedings of the KOSOMBE Conference
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• v.1993 no.11
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• pp.13-16
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• 1993

In this paper the morphological characteristic parameters according to the Lee's physical constitution theory are suggested using the X-ray computed tomography. The Lee's physical constitution theory is classify into 4 physical constitutional types by the relative degree of visceral function: those are macro-negative(strong liver- weak lung), micro-negative(strong kidney- weak spleen), micro-positive(strong spleen- weak kidney) and macro-positive(string lung- weak liver). The morphological characteristic parameters are the following. The AA-line is the distance between Rt. & Lt. acupuncture point keug-cheun. The BB-line is the length of lung. The CC-line is the longest width of thorax. The DD-line is the vertical distance between the CC-line and the EE-line. The EE-line is the distance between the Rt. and Lt. anterior superior iliac spines. As the results macro-negative(strong liver-weak lung) has the longest CC-line and the short BB-line. Micro-negative(strong kidney-weak spleen) has the longest EE-line and the short CC-line. Micro-positive(strong spleen-weak kidney) has the longest DD-line and the short BB-line. And macro-positive(strong lung-weak kidney) has the longest BB-line and the short EE-line.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.294-299
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• 2001

The old technique of sandblasting which has been used for decoration of glass surface has recently been developed into a powder blasting technique for various materials, capable of producing micro structures larger than 100 m. This paper describes the performance of powder blasting technique in micro-line grooving of glass and the effect of the number of nozzle scanning on the depth and width of line groove. Experimental results showed that increasing the no. of nozzle scanning resulted in the increase of depth and width in grooves. Increase of width which may cause several problems in the precision machining results from wear of mask film.

• 한국가시화정보학회:학술대회논문집
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• 2002.11a
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• pp.31-34
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• 2002

Imaging techniques using x-ray beam at high energies (>6KeV) such as contact radiography, projection microscopy, and tomography have been used to nondestructively discern internal structure of objects in material science, biology, and medicine. This paper introduces the x-ray micro-imaging method using 1B2 micro-probe line of PAL (Pohang Accelerator Laboratory). Cross-sectional information on low electron density materials can be obtained by probing a sample with coherent synchrotron x-ray beam in an in-line holography setup. Living organism such as plants, insects are practically transparent to high energy x-rays and create phase shift images of x-ray wave front. X-ray micro-images of micro-bubbles of $20\~120\;{\mu}m$ diameter in an opaque tube were recorded. Clear phase contrast images were obtained at Interfaces between bubbles and surrounding liquid due to different decrements of refractive index.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.689-693
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• 2005

Inkjet printing is a non-contact and direct writing associated with a computer. In the industrial field, there have been many efforts to utilize the inkjet printing as a new way of manufacturing, especially for electronic devices. For the application of inkjet printing to electronic field, one of the key factors is exact realization of designed images into printed patterns. In this work, micro patterning for conducting line has been studied using the piezoelectric print head and silver nano ink. Dimensions of printed images have been predicted in terms of print resolution and diameter of a single dot. The predicted and the measured values showed consistent results. Using the results, the design capability for industrial inkjet printing could be achieved.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.7
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• pp.647-655
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• 2003

Commonly used SAW duplexers have a difficulty on manufacture so that a transmission line is printed on the package or an LTCC multi-layer is needed because a quarter-wave transmission line which is a kind of an isolation network is applied to the SAW duplexers. In this study, new structures of one chip type SAW duplexers are proposed. In the proposed structure, Tx and Rx SAW ladder filters and isolation networks are located on a single 36LiTaO$_3$ piezoelectric substrate. The manufacture process is very simple than commonly used product. It is possible to improve tile performance by means of optimizing the micro-strip line lumped elements. It is easy to integrate and modulate with other surrounding components. The optimal design techniques can be applied to other kind of multi-port devices.