• Journal of Microbiology and Biotechnology
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• v.28 no.2
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• pp.298-304
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• 2018

The single-vessel multienzyme UDP-${\alpha}$-$\text\tiny{D}$-glucose recycling system was coupled with a forward glucosylation reaction to produce novel glucose moiety-conjugated derivatives of different tetracycline antibiotic analogs. Among five tetracycline analogs used for the reaction, four molecules (chlorotetracycline, doxytetracycline, meclotetracycline, and minotetracycline) were accepted by a glycosyltransferase enzyme, YjiC, from Bacillus licheniformis to produce glucoside derivatives. However, the enzyme was unable to conjugate sugar units to rolitetracycline. All glucosides of tetracycline derivatives were characterized by ultraviolet absorbance maxima, ultra-pressure liquid chromatography coupled with photodiode array, and high-resolution quadruple time-of-flight electrospray mass spectrometry analyses. These synthesized glucosides are novel tetracycline derivatives.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.699-702
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• 2004

Next generation lithography technologies, such as EBL(Electron Beam Lithography), X-ray lithography, SPL(Scanning Probe Lithography), have been studied widely for getting over line width limitation of photolithography. Among the next generation lithography technologies, SPL has been highlighted because of its high resolution advantage. But is also has problem which are slow processing time and sample size limitation. The purpose of this study is complement of present SPL system. Brand new SPL system was made. SPL test was performed with the system in ultra thin PMMA(polymethlymethacrylate) film.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.4
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• pp.246-252
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• 2017

Non-invasive and non-restrictive methods for measuring the physiological functions of the human body are useful for health care, security, and surveillance. In this paper, a new method that extracts human heartbeat information by utilizing ultra-wideband (UWB) impulse radar is proposed. The amplitude spectra of received radar pulses reflected from the human body are accumulated at specific time intervals, and chirp z-transform (CZT) is used to extract the heartbeat frequency from the amplitude spectra. The heartbeat frequency can be extracted with high-frequency resolution in the frequency band of the heartbeat of interest using CZT. Experimental results to verify the performance of the proposed method show that a highly accurate extraction of the heartbeat frequency is possible using this method.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1043-1047
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• 2003

With the advancement of micro-systems and nanotechnology, the need for ultra-precision fabrication techniques has been steadily increasing. In this paper, a novel nano-structure fabrication process that is based on the fundamental understanding of nano-scale tribological interaction is introduced. The process, which is called Mechano-Chemical Scanning Probe Lithography (MC-SPL), has two steps, namely, mechanical scribing for the removal of a resist layer and selective chemical etching on the scribed regions. Organic monolayers are used as a resist material, since it is essential for the resist to be as thin as possible in order to fabricate more precise patterns and surface structures. The results show that high resolution patterns with sub-micrometer scale width can be fabricated on both silicon and various metal surfaces by using this technique.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.342-344
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• 2006

During last years, large investments have been directed to development and research of nano-technological products like semiconductor, display panel, optic-fiber communication components, life technology, and ultra-precision components. All quantitative measurements at nanometre scale should guarantees accurate results and high quality. Laser interferometer is one of most famous nanometre scale devices to be able to measure metre-scale distance with nanometre scale resolution, but it is easily affected by various error causes like geometrical, instrumental and environmental factor. On the other side, capacitive sensor is robust to above error factors, but it is able to measure relatively shorter distance, under $100{\mu}m$, than laser interferometer. New error correction method for laser interferometry using capacitive sensor will be introduced in this paper.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.234-236
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• 2006

Because of its long measurement range and ultra-precise resolution. the heterodyne laser interferometer systems are very common in various industry area such as semiconductor manufacturing. However the periodical nonlinearity property caused from frequency mixing is an obstacle to improve the high measurement accuracy in nanometer scale. In this paper to minimize the effect of nonlinearity, we propose an adaptive nonlinearity compensation algorithm. We first compute compensation parameters using least square (LS) with the capacitance displacement sensor as a reference input. We then update the parameters with recursive LS (RLS) while the values are optimized to modify the elliptical phase into circular one. Through comparison with some experimental results of laser system, we demonstrate the effectiveness of our proposed algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.463-463
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• 2000

A dual-stage positioner for fast and fine robotic manipulations is presented. By adopting the merits of both coarse and fine actuator, a desirable system having the capacity of large workspace with high resolution of motion is enabled. We have constructed an ultra precision XY positioner with dual-stage mechanism where the PZT driven fine stage is mounted on the motor driven XY positioner and applied it to fine tracking controls and micro-tele operations as a slave manipulator. We describe essential merits of the compound actuation mechanism and some control strategies to successfully utilize it with proper servo system design. Through experimental results, the effectiveness of the coarse/fine manipulation by the dual-stage positioner will be shown.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.662-667
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• 1996

For compensating the error motion of hydrostatic guideways, the structure and the theoretical design method of ACC(Active Controlled Capillary) are proposed. The maximum controllable range, micro step response and dynamic characteristics of ACC are analyzed experimentally for verifing the availability. The experimental results showed that by the use of ACC, the error motion within 2.7${\mu}{\textrm}{m}$ of a hydrostatic guideway can be compensated with the resolution of 27nm, 1/100 of uncontolled error, and the frequency band of 5.5Hz. From these results, it Is confirmed that the ACC is very effect to improve the moving accuracy of high or ultra precision hydrostatic guideways.

• Journal of the Korean Vacuum Society
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• v.2 no.2
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• pp.145-151
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• 1993

Ultra High Vacuum chamber for surface analysis and a series of AES-LEED controllers for LEED optics was designed and constructed. Electron energy resolution of LEED optics was tested. On the basis of the layer by layer mode, thickness of evaporated Ni on Pt(111) was calculated from the Auger signal ratio.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.128-131
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• 2002

Three Dimensional measuring system using optical interference is greatly needed for semiconductor surface or optical surface. The application of this system are : MEMS product, semiconductor surfaces, optical components, precise machined surface, etc. In this paper, Interferometry based measurement system is introduced, which is nondestructive and noncontact inspection system. This system have relatively many advantage, compared with AFM/STM, SEM, Stylus, etc. The developed system can measure the surface topography with high precision and resolution, and with few seconds. And the associated software algorithm is also developed for the ultra precision 3D measuring surface. Various samples that is measured using this system is showed in the latter of this paper.