• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.332-337
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• 2003

Enzyme kinetics data play a vital role in the design of reactors and control of processes. In the present study, kinetic studies on pectinases were carried out. Partially purified polymethylgalacturonase (PMG) and polygalacturonase (PG) were the two pectinases studied. The plot of initial rate vs. initial substrate concentration did not follow the conventional Michaelis-Menten kinetics, but substrate inhibition was observed. For PMG, maximum rate was attained at an initial pectin concentration of 3 g/l, whereas maximum rate was attained when the initial substrate concentration of 2.5 g/l of polygalacturonic acid for PG I and PG II. The kinetic data were fitted to five different kinetic models to explain the substrate inhibition effect. Among the five models tested, the combined mechanism of protective diffusion limitation of both high and inhibitory substrate concentrations (semi-empirical model) explained the inhibition data with 96-99% confidence interval.

• Journal of the Korean Society for information Management
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• v.8 no.2
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• pp.96-107
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• 1991

The inherent limitation of the conventional approaches in automatic indexing lies in the fact that they compute the relevancy between index terms and documents rather indirectly or relatively. As an alternative the anlaysis of document texts seeks a means of establishing a direct relevancy of the terms. More rigorous linguistic analysis will ensure better chance of relevancy. Various semantic topologies among terms may suggest the sufficient quality for relevancy. The enhanced and guaranteed relevance will allow the high precision of retrieval. Along with this line the on going project in KAIST pursues the user oriented retrieval system that spawns still may other issues that are not c o m n in traditional perspective.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.1006-1011
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• 2008

In this paper, we developed a system for large scale on-line interactive game server based on Platform as a Service(PaaS). Small and medium sized game developing companies have various aspects of limitation to launch a large scale on line game site. By using the system proposed in this paper, small and medium sized game developing companies can easily publish their games into market.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.6
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• pp.971-981
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• 1994

In this paper, we consider feedback-linearizing control of VR (Variable Reluctance) motors which have been increasingly used in high performance direct-drive applications. We characterize all torque controllers that can make the generated torque of a VR motor linear to torque command but without torque ripple. The torque controlles maximize the range of torque commands which are admissible under the physical limitation in stator currents. The whole class of all such torque controllers is parameterized in the explicit form which contains a function to be chosen freely. This free function can be used to achieve other control objectives as well as linear dynamic characteristics. As the examples for optimal choices of the free function, we actually determine two optimal free functions, one for minimal rate of change in current commands and the other for minimal power loss due to stator resistance. To illuminate further the practical use of torque controllers proposed in this paper, we present some experimental results for the case of a commercially available VR motor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.265-266
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• 2006

It was well known that thermopile was quiet a competent sensor using to probe the temperature of "hot point" where the temperature can be off the temperature-limitation for normal operation of the main electrical power equipment. In the present work, we aimed for developing new Ge-thermopile materials which can be using a non-contact temperature sensors at various hot-point of the power equipment and evaluation of its output property. As a results of the present works, a new thermopile which were composed Ga-poded p-type and Sb-doped n-type in Ge-semiconductor were designed and manufactured by MBE(Molecular Beam Epitaxy) process and showed superior sensitivity at room temperature.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.282-282
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• 2006

Nanoporous organosilicate thin films were realized by the microphase separation of pore generating components mixed with an organosilicate matrix. The refractive index of such nanoporous organosilicate films can be tuned in the range of $1.40{\sim}1.22$. With a nanoporous single layer with n ${\sim}1.225,\;99.85\;%$ transmittance in the visible range was achieved. In order to overcome the limitation on the narrow wavelength for high transmittance imposed by single nanoporous thin films, bilayer thin films with different reflectance for each layer were prepared by inserting high refractive index layer with a refractive index of 1.447. It is demonstrated that the novel broadband antireflection coating with improved transmittance can be easily achieved by the nanoporous bilayer thin films described in present study.

• Journal of Welding and Joining
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• v.20 no.2
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• pp.77-81
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• 2002

Many kinds of Pb-free solder have been investigated because of the environmental concerns. Sn-Ag-Cu system is well blown as most competitive Pb-free solder. However, since Sn-Ag-Cu system has relatively high melting point compared to Sn-Pb eutectic, it may a limitation, the some application. In this study, Bi and In contained solder of $Sn_3Ag_8Bi_5In$ which has relatively lower melting point, $188~204^{\circ}C$, was investigated. $Sn_3Ag_8Bi_5In$ solder ball of $500\mu\textrm{m}$ diameter was set on the Ni/Cu/Cr-UBM and reflow soldered in the range of $220~240^{\circ}C$ for 5~15s. The maximum shear strength of the solder ball was around 170mN by reflowing at $240^{\circ}C$ for 10s. Intermetallic compound formed on the UBM of Si-wafer was analysed by SEM(scanning electron microscope) and XRD(X-ray diffractometer).

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.1
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• pp.156-161
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• 2017

This work presents a novel structure for junction-less tunneling field effect transistor (JL-TFET) with a floating gate over the source region. Introduction of floating gate instead of fixed metal gate removes the limitation of fabrication process suitability. The proposed device is based on a heavily n-type-doped Si-channel junction-less field effect transistor (JLFET). A floating gate over source region and a control-gate with optimized metal work-function over channel region is used to make device work like a tunnel field effect transistor (TFET). The proposed device has exhibited excellent ID-VGS characteristics, ION/IOFF ratio, a point subthreshold slope (SS), and average SS for optimized device parameters. Electron charge stored in floating gate, isolation oxide layer and body doping concentration are optimized. The proposed JL-TFET can be a promising candidate for switching performances.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.6
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• pp.546-551
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• 2005

[ ${\beta}-1,3-Glucan$ ] (curdlan) is a water-insoluble polysaccharide composed exclusively of ${\beta}-1,3\;linked$ glucose residues. Extracellular curdlan was mostly synthesized by Agrobacterium species and Alcaligenes faecalis under nitrogen-limiting conditions. In this study, we screened the microorganisms capable of producing extracellular curdlan from soil samples. For the first time, we reported Gram-positive bacterium Bacillus sp. SNC 107 capable of producing extracellular curdlan in appreciable amounts. The effect of different carbon sources on curdlan production was studied and found that the yield of curdlan was more when glucose was used as carbon source. It was also found that maximum production was achieved when the initial concentration of ammonium and phosphate in the medium was 0.5 and 1.9 g/L respectively. In this study the curdlan production was increased from 3 to 7g/L in shake flask cultures.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.181.3-181
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• 2001

Recently, the study on development of electrical and electronic device is done to get miniature, high degrees of integration and efficiency by using inorganic materials. the study of Langmuir-Boldgett(LB) method that uses organic materials because of the limitation for the ultrasmall size. In this paper, to do research for medical artificial organs as well as principal parts living body thin film application, electrical properties of L-$\alpha$-DLPC Langmuir(L) films were investigated a displacement current measuring technique with pressure stimulation. We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is 20[mN/m]. LB layers of L-$\alpha$-DLPC deposited by LB method ...