• 한국생물공학회:학술대회논문집
• /
• 2003.10a
• /
• pp.692-695
• /
• 2003

In this work immobilization technique of enzymes onto the magnetic nanoparticles has been developed for biochip applications. Glucose oxidase and lactate dehydrogenase were immobilized on magnetic nanoparticles via cyanamide and glutaraldehyde. Immobilized enzymes had good operational and storage stability The immobilized glucose oxidase and lactate dehydrogenase were characterized by some factors(pH, temperature, and components of buffer solution etc) which affect the activity, In order to characterize the magnetic nanoparticles, we have used transmission electron microscopy(TEM), X-ray diffraction(XRD) and Fourier transform infrared(FTIR).

• 한국생물공학회:학술대회논문집
• /
• 2005.04a
• /
• pp.120-122
• /
• 2005

Phospholipases C (PLCs) from B. cereus 318 and recombinant Pichia pastoris were immobilized on sol-gel coated glass beads. The pH and temperature on immobilized PLC activity were investigated. Operational and storage stability of the immobilized PLCs was measured by spectro- photometric assay. The PLCs immobilized on sol-gel coated glass beads were photographed by scanning electron microscope (SEM).

• Proceedings of the KIEE Conference
• /
• 2008.11a
• /
• pp.217-219
• /
• 2008

Among the Flexible AC Transmission Systems (FACTS) devices, Unified Power Flow Controller (UPFC) is considered as the most powerful and versatile one as it provides simultaneous, real time control of the transmission parameters, voltages, impedances, and phase angles which determine the power flow in AC transmission systems. This paper presents modelling of UPFC and describes its characteristics. The UPFC implemented in this paper is based on Sinusoidal Pulse Width Modulation (SPWM) and Electro-Magnetic Transients Program (EMTP)/ATPDraw is used to model and analyze it. The simulation results confirm advantages of UPFC in operational performance with respect to the steady state Power flow regulation and the transient stability control.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.2
• /
• pp.465-473
• /
• 2015

The increasing need to improve transient security assessment of existing or forecasted operating conditions of networks by power system operators is major concern of the power system security monitoring problem at the Energy Management Systems. This paper proposes a preventive control of transient stability with generation rescheduling based on rotor trajectory index obtained using time domain simulations. This index may help power engineers in making operational decision and to obtain a generation configuration with better transient security dispatch. The effectiveness of the proposed methodology is demonstrated on IEEE 39-bus New England system for a three phase fault at different loading conditions with single and multiple line outage cases.

• Microbiology and Biotechnology Letters
• /
• v.24 no.6
• /
• pp.738-742
• /
• 1996

An efficient packed-bed type biofilm reactor charged with immobilized phototrophs was developed to treat organic wastewater at an extremely high volumetric loading rate. The packed bed reactor (PBR) charged with porous ceramic beads was superior to a fluidized-bed reactor suspended with activated carbon powders in terms of many aspects such as BOD removal efficiency, operational stability, and overall economics. For wastewater with BOD concentration as high as 20, 000mg/l, the BOD removal efficiency was maintained above 90% when the hydraulic retention time (HRT) was longer than 1 day. The allowable volumetric BOD loading rate of this reactor (20gBOD/l day) is more than ten-folds higher than that of an ordinary activated sludge method. The behaviour of the reactor was represented well by a Monod type kinetic equation with a maximum specific BOD loading rate(P) of 22.2gBOD/l day and a half saturation constant(K$_{s}$) of 1, 750 mgBOD/l.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2011.11a
• /
• pp.162-163
• /
• 2011

This paper presents the system dynamics methodology for modeling and control the production/inventory system. Under system dynamics point of view, we can apply some production/inventory policies as if we use the control laws for dynamics systems, then the behavior of system is analyzed and evaluated to improve the performance of production/inventory system. We also utilize the hybrid modeling method for the dynamic of production system with the combination of Matlab/Simulink and Matlab/Sateflow. Finally, the numerical simulation results are carried out in Matlab/Simulink environment and compare with the results from other works. It is shown that our approach can obtain some good performances (such as operational cost, stability of inventory, customer service level).

• Proceedings of the KIPE Conference
• /
• 2004.07b
• /
• pp.686-690
• /
• 2004

This paper describes the performance improvement of transient response and the modeling of small aircraft onboard generator. As the characteristics of the stator coil which are a major parameters of transient response were improved, the characteristics of transient response could be increased, therefore, the improved generator can be satisfied with large and fast load changes. Established the control model of the generator, it could be possible to do the analysis of generator performance, and improve the operational stability of the generator system using the control model.

• Proceedings of the KIEE Conference
• /
• 1999.11a
• /
• pp.35-42
• /
• 1999

As our power system has changed the past undeveloped model causing the lacked supply of power to the civilized model that the remained one makes the voltage and the frequency rise at the middle of the night, the leading power factor operation of generators, that is, the under-exited operation is essentially to be needed, so, at a viewpoint of the stability of the power system, it is a very important factor. In this investigation. the equation of curves for each area on the capability curve has been studied at the above-mentioned viewpoint. Also, each capability curve for the operating power stations (Nuclear P/S, Thermal P/S, Hydrolic & pumping-up P/S Gas turbine P/S) has, been presented, and studied whether the leading power factor operational area is able to be expanded or not.

• Journal of Information Display
• /
• v.12 no.4
• /
• pp.219-222
• /
• 2011

Iridium-(III)-bis[(4,6-di-fluorophenyl)-pyridinate-N,$C^2$' ]picolinate-based blue phosphorescent organic light-emitting diodes with different electron transport materials were fabricated. Each electron transport material had different electron mobilities and triplet energies. The device with 1,3,5-tri(m-pyrid-3-yl-phenyl)benzene had the highest external quantum efficiency (20.1%) and luminous current efficiency (33.1 cd/A) due to its high electron mobility and triplet energy. The operational stability of each device was also compared with that of the others. The device with 2,2',2"(1,3,5-benzenetriyl)tris-(1-phenyl-1H-benzimidazole) was found to have a longer lifetime than the other devices.

• Transactions of the Korean hydrogen and new energy society
• /
• v.14 no.4
• /
• pp.283-290
• /
• 2003

To clarify the cause of backfire occurrence and realize a hydrogen fueled engine linear alternator system, dynamic characteristics of a free-piston hydrogen engine were analyzed and compared with those of conventional reciprocating engines. It was found that the mean velocity and acceleration of a free-piston engine were higher than those of reciprocating engines. Piston displacement and compression ratio were varied with the change of the fuel mass flow rate. Therefore, the operational stability and controllability were the most important thinks of the development of a free-piston hydrogen engine.