• Journal of IKEEE
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• v.22 no.2
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• pp.356-361
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• 2018

We investigated a hydrogen gas sensor which is available in a high temperature atmosphere. The hydrogen sensors were fabricated into a metal-oxide-semiconductor (MOS) structure made of $Pd/Ta_2O_5/SiC$, and the thin tantalum oxide ($Ta_2O_5$) layer was fabricated by rapid thermal oxidation (RTO). In the experiment, we made three types of sensors with different palladium (Pd) patterns to evaluate the effect of Pd electrode on response characteristics. As the result, the response characteristics in capacitance were improved further when the filled area of the Pd electrode became larger.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.297-300
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• 2002

Application of electronic nose and PLD chip design was developed to be used in gas discrimination system for limited kinds of gas. An array of 4 metal oxide gas sensors with different selectivity patterns were used in order to measure gases. BP(Back Propagation) algorithm was designed and implemented on CPLD of two hundred thousand gate level chips by VHDL language for processing input signals from 4 kinds of gas sensors. This module successfully discriminated 4 kinds of gases and displayed the results on LCD and LED. The developed module could be used for various applications in the field of food process control and alcohol judgment.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1176-1179
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• 2002

This paper presents the use of a Genetic Algorithm to find the optimal layout for the placement of garment patterns on a fabric of fixed width to minimize fabric waste. We developed a program to simulate garment pieces and their layout on a fixed-width fabric. Each piece in the order book is placed with 2 possible orientations: 0 degrees and 180 degrees. The efficiency is measured by the length of fabric used after all the patterns in the order book have been laid out. A comparison is made between the placement using our proposed genetic algorithm to that made by an expert human using our simulation program. The results from our experiments on various pattern designs indicate that our genetic algorithm can effectively be used to obtain highly efficient solutions, comparable to that done by an expert while using a reasonable amount of time. The algorithm can also be adapted for use in other areas related to optimal consumption of sheet material such as metal, paper, and leather.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1045-1048
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• 2003

In this paper, we studied plasma damage of MIS capacitor with $Al_2$O$_3$ dielectric film. Using capacitor pattern with the same area but different perimeters, we tried to separate etching damage mechanism and to optimize the dry etching process. After etching both metal and dielectric layer by the same condition, leakage current and C-V measurements were carried out for Pt/A1$_2$O$_3$/Si structures. The flatband voltage shift was appeared in the C-V plot, and it was caused by the variation of the fixed interface charge and the interface trapped charge. From I-V measurement, it was found the leakage current along the periphery could not be ignored. Finally, we established the process condition of RF power 300W, 100mTorr, Ar/Cl$_2$ gas 60sccm as an optimal etching condition.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1021-1024
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• 2003

In this work, we fabricated various 2D metallic and polymeric nanopatterns with the feature resolution of sub-micrometer scale by using the method of microcontact printing ($\mu$ P) based on soft lithography. Silicon masters for the micromolding were made by e-beam lithography. Composite poly(dimethylsiloxane) (PDMS) molds were composed of a thin, hard layer supported by soft PDMS layer. Finally, monodisperse metal or polymer particles could be obtained in the prepared pattern for the application of electronic devices.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1296-1301
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• 2003

The chemical mechanical polishing(CMP) is necessarily applied to manufacturing the dielectric layer and metal line in the semiconductor device. The conditioning of polishing pad in CMP process additionally operates for maintaining the removal rate, within wafer non-uniformity, and wafer to wafer non-uniformity. But the fixed abrasive pad(FAP) using the hydrophilic polymer with abrasive that has the swelling characteristic by water owns the self-conditioning advantage as compared with the general CMP. FAP also takes advantage of planarity, resulting from decreasing pattern selectivity and defects such as dishing due to the reduction of abrasive concentration. This paper introduces the manufacturing technique of FAP. And the tungsten CMP using FAP achieved the good conclusion in point of the removal rate, non-uniformity, surface roughness, material selectivity, micro-scratch free contemporary with the pad life-time.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.3
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• pp.14-17
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• 2006

To diagnosis abnormal compressor conditions in an air-conditioner, the acoustic emission (AE) signal, which is derived from wear condition, compressed air, and assembly error, was analyzed experimentally. Burst and continuous type AE signals resulted from metal contact and compressed air, and the raw AE signal of compressors was acquired in the production line. After extracting samples using waveforms, the Early Life Test (ELT) was conducted and the waveform was classified as normal or abnormal. Efficient parameters in the waveform pattern were investigated in time and frequency domains and a diagnosis algorithm for air-conditioners using Neural Network estimation is suggested.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.388-392
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• 2003

As the machine tool industry progresses, the performance of cutting tools also needs to be of good quality and specialized. If the existing metal cutting tool tip is coated properly, its life would be longer and the machining of a difficult-to-cut material also could be possible. For the development of the high quality cutting tool, the applicabilities of TiAIN coating deposited by PVD on the cutting insert were experimentally investigated. The various measurements, such as, SEM micrograph, XRD pattern, AFM surface morphology, and hardness were performed to cross-check the possibility and availability of TiAIN coated tool in the field. The effects of it is successful and we hope to see good results in many fields.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.309-312
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• 2001

A primitive gas classification system which can classify limited species of gas was designed and simulated. The 'electronic nose' consists of an array of 4 metal oxide gas sensors with different selectivity patterns, signal collecting unit and a signal pattern recognition and decision Part in PLD(programmable logic device) chip. Sensor array consists of four commercial, tin oxide based, semiconductor type gas sensors. BP(back propagation) neutral networks with MLP(Multilayer Perceptron) structure was designed and implemented on CPLD of fifty thousand gate level chip by VHDL language for processing the input signals from 4 gas sensors and qualification of gases in air. The network contained four input units, one hidden layer with 4 neurons and output with 4 regular neurons. The 'electronic nose' system was successfully classified 4 kinds of industrial gases in computer simulation.

• Current Optics and Photonics
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• v.3 no.6
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• pp.566-570
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• 2019

To investigate dependence of the sensitivity of THz metamaterials on the position of target dielectric materials, we functionalized the metamaterial gap with an adhesive polymer. A shift in resonance frequency occurs when polystyrene microbeads are deposited in the gap of the metamaterial's metal resonator pattern, while little change is observed when they are deposited on other areas of the metasurface. A two-dimensional mapping of the sensitivity, with a grid size of 1 ㎛, is obtained from a finite-difference time-domain simulation: The frequency shift is displayed as a function of the position of a target dielectric cube. The resulting sensitivity distribution clearly reveals the crucial role of the gap in sensing with metamaterials, which is consistent with the electric field distribution near the gap.