• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.3
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• pp.24-31
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• 2004

A successful on-line monitoring system for conventional machining operations has the potential to reduce cost, guarantee consistency of product quality, improve productivity and provide a safer environment for the operator. In fine-shape machining, typical signs of tool problems such as vibration, noise, chip flow characteristics and visual signs are almost unnoticeable without the use of special equipment. These characteristics increase the importance of automatic monitoring in fine-shape machining, however, sensing and interpretation of signals ar more complex. In addition, the shafts of the mini-tools break before the typical extensive cutting edge of the tool gets damaged. In this study, the existence of a relationship between the characteristics of the cutting force and tool usage was investigated, and tool breakage detection algorithm by LabVIEW was developed and the following results are obtained. It was possible to use a relative error compare which mainly used in established experiment and investigated tool breakage detection algorithm in time domain which can detect AE and cutting force signals more effective and accurate.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.233-237
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• 2017

The dual-channel receiver MMIC which is composed of LNA, Mixer, LO-amp and temperature compensation circuit is designed on a single chip. For the performance comparison, a FMCW radar transceiver module using commercial MMICs is also implemented. As a result, Multi-channel Transceiver using manufactured MMIC shows an improved performance such as noise figure and gain flatness compare to purchased MMIC.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.6 s.348
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• pp.53-61
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• 2006

In high speed flash type or pipelining type A/D Converter, the faster sampling frequency is, the more the effect of DC reference fluctuation is increased by clock feed-through and kick-back. When we measure A/D Converter, further, external noise increases reference voltage fluctuation. Thus reference fluctuation reduction circuit must be needed in high speed A/D converter. Conventional circuit simply uses capacitor but layout area is large and it's not efficient. In this paper, a reference fluctuation reduction circuit using transmission gate is proposed. In order to verify the proposed technique, we designed and manufactured 6bit 2GSPS CMOS A/D converter. The A/D converter is based on 0.18um 1-poly 5-metal N-well CMOS technology, and it consumes 145mW at 1.8V power supply. It occupies chip area of $977um\times1040um$. Experimental result shows that SNDR is 36.25 dB and INL/DNL ${\pm}0.5LSB$ when sampling frequency is 2GHz.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.557-557
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• 2012

Silicatein-${\alpha}$, the enzyme extracted from silica spicules in glass sponges, has been studied extensively in the way of chemistry from 1999, in which the pioneering work by Morse, D. E. - the discovery of the enzymatic hydrolysis in Silicatein-${\alpha}$ - was published. Since its reaction conditions are physiologically favored, synthesis of various materials, such as gallium oxide, zirconium oxide, and silicon oxide, was achieved without any hazardous wastes. Although some groups synthesized oxide films and particles, they have not achieved yet controlled morphogenesis in the reaction conditions mentioned above. With the knowledge of catalytic triad involved in hydrolysis of silicone alkoxide and oligomerization of silicic acid, we designed the novel peptide amphiphiles to not only form self-assembled structure, but also display similar activities to silicatein-${\alpha}$. Designed templates were able to self-assemble into left-handed helices for the peptide amphiphiles with L-form amino acid, catalyzing polycondensation of silicic acids onto the surface of them. It led to the formation of silica helices with 30-50 nm diameters. These results were characterized by various techniques, including SEM, TEM, and STEM. Given the situation that nano-bio-technology, the bio-applicable technology in nanometer scale, has been attracting considerable attention; this result could be applied to the latest applications in biotechnology, such as biosensors, lab-on-a-chip, biocompatible nanodevices.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2003.10a
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• pp.66-72
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• 2003

Toxicogenomics is now emerging as one of the most important genomics application because the toxicity test based on gene expression profiles is expected more precise and efficient than current histopathological approach in pre-clinical phase. One of the challenging points in Toxicogenomics is the construction of intelligent database management system which can deal with very heterogeneous and complex data from many different experimental and information sources. Here we present a new Toxicogenomics database developed as a part of 'Toxicogenomics for Efficient Safety Test (TEST) project'. The TEST database is especially focused on the connectivity of heterogeneous data and intelligent query system which enables users to get inspiration from the complex data sets. The database deals with four kinds of information; compound information, histopathological information, gene expression information, and annotation information. Currently, TEST database has Toxicogenomics information fer 12 molecules with 4 efficacy classes; anti cancer, antibiotic, hypotension, and gastric ulcer. Users can easily access all kinds of detailed information about there compounds and simultaneously, users can also check the confidence of retrieved information by browsing the quality of experimental data and toxicity grade of gene generated from our toxicology annotation system. Intelligent query system is designed for multiple comparisons of experimental data because the comparison of experimental data according to histopathological toxicity, compounds, efficacy, and individual variation is crucial to find common genetic characteristics .Our presented system can be a good information source for the study of toxicology mechanism in the genome-wide level and also can be utilized fur the design of toxicity test chip.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.6 s.336
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• pp.1-8
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• 2005

In this paper, CMOS A/D converter with 6bit 2GSPS Nyquist input at 1.8V is designed. In order to obtain the resolution of 6bit and the character of high-speed operation, we present an Interpolation type architecture. In order to overcome the problems of high speed operation, a novel One-zero Detecting Encoder, a circuit to reduce the Reference Fluctuation, an Averaging Resistor and a Track & Hold, a novel Buffered Reference for the improved SNR are proposed. The proposed ADC is based on 0.18um 1-poly 3-metal N-well CMOS technology, and it consumes 145mW at 1.8V power supply and occupies chip area of 977um $\times$ 1040um. Experimental result show that SNDR is 36.25 dB when sampling frequency is 2GHz and INL/DNL is $\pm$0.5LSB at static performance.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.45-48
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• 2003

In the research of proteomics, mass spectrometry analysis is the essential method for identification of the unknown proteins. Trypsin treatment for the sample preparation of mass spectrometry is the inevitable procedure[1]. However, sample preparation procedure is cumbersome and time consuming. To resolve these problems, Temperature controllable microreactor was designed and fabricated. It consists of metering chamber, micro channel, reaction chamber, platinum (Pt) thin film heater and a temperature sensor so that micro metering and mixture of reagent with temperature control can be done on the same chip. The total size of the fabricated microreactor was $37{\times}30{\times}1\;mm^3$ and the size of channel cross section was $200{\times}100{\mu}m^2$. PID temperature controller was realized using NI DAQ, PCI-MIO-l6E-1 board and LabVIEW program.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.18.2-18.2
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• 2011

생활수준이 향상되고, 환경오염이 가속되면서 환경에 대한 관심이 더욱 증대되고 있다. 수질센서의 경우, 그 측정 항목이 매우 다양하고, 높은 정밀도를 요하고 있을 뿐만 아니라 지속적인 실시간 모니터링을 요구하고 있어, 기술적으로 해결해야 할 문제가 많이 남아 있다. 또한, 현재 약 15% 정도로 매우 낮은 국산화율을 보이고 있어, 대부분의 주요 센서들이 수입에 의존하고 있는 실정이다. 수질을 측정하기 위한 센서는 크게 두 가지 형태로 나누어 질 수 있는데, 하나는 flow injection analysis (FIA) 방식이며, 다른 하나는 Probe 방식의 센서이다. 본 발표에서는 수질 센서에 대한 최근 국내 기술 동향과, 수질 모니터링을 위한 Lab-on-a-chip 형 암모니아 분석 칩, Probe 형 중금속 센서 연구 개발 결과를 요약하고자 한다. 암모니아 분석 칩은 마이크로 유체 소자 내에서 Berthelot reaction을 유도하고, 흡광법에 의하여 물 속에 존재하는 암모니아를 간접적으로 측정하는 방법이다. 또한, 중금속 센서로 일반적인 working electrode 소재로 사용되는 독성이 있는 Hg 보다 친환경적인 개발된 bismuth-modified carbon nanotube와 같은 Bi계 복합소재를 적용하여 물 속에 존재하는 저 농도의 Pb, Cd, Zn을 측정 분석할 수 있었다. 본 연구를 통해 개발된 분석칩과 중금속 센서를 이용하여 하천에서 샘플링된 물에서의 암모니아 및 중금속 농도를 각각 분석할 수 있었다.

• Design & Manufacturing
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• v.2 no.2
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• pp.25-28
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• 2008

Micro fabrication of biochip such like lab-on-a-chip becomes increasingly important. In this study, we designed and manufactured of new molds which were main factors for forming process in order to mass produce of biochip using forming process. Forming analysis of biochip was performed by Moldflow software. Results of this study are able to design and manufacture the mold which can be easy to eject the workpiece by using the slide mechanism for biochip.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2407-2409
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• 2005

본 논문에서는 다양한 생물분자 감지를 위한 센서로 마이크로캔틸레버를 제안하였고 이것을 이용해 여러 생물 분자들을 광학적, 전기적으로 분석하였다. 마이로캔틸레버는 표면 미세 가공 기술로 제작되었고, 이러한 제작 방식은 공정이 간단하고 비용이 적게 들며 센서 array가 가능하다는 장점을 갖는다. 생물분자를 포함하는 용액을 주입하기 위하여 PDMS와 fused silica glass를 이용해 fluid cell system을 제작하였다. 마이크로캔틸레버 상단의 gold가 코팅된 부분에서 생물분자의 자기조립 (self assembly)현상이 일어나고 이는 마이크로캔틸레버 상, 하단의 표면 스트레스 차이를 야기 시킨다. 이로 인해 마이크로캔틸레버 자체의 휘어짐 현상이 일어나게 되고 이러한 휘어진 정도를 측정함으로써 마이크로캔틸레버의 생물분자 감지능을 확인할 수 있었다. Cystamine dihydrochloride와 glutaraldehyde 분자를 분석하였고 각기 다른 농도의 cystamine dihydrochloride 용액에서도 실험함으로써 농도별 감지능 또한 확인하였다. 이러한 생물분자 감지를 위한 마이크로캔틸레버의 센서로써의 성능은 u-TAS 와 lab-on-a-chip에서 유용히 이용될 수 있으리라 확신한다.