• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.70-75
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• 1991

Continuous and simultaneous production of gluconic acid and sorbitol from glucose and fructose was carried out by using glucose-fructose oxidoreductase and glucanolactonase of Zymomonas mobilis. In order to utilize the enzymes without purification, Zymomonas mobilis was permeabilized with toluene. Optimum conditions for permeabilization and reaction kinetics of permeabilized Zymomonas mobilis were studied. In batch operation with the permeabilized cells immobilized in alginate beads, about 90% conversion was obtained within 35 h reaction. Continuous production of gluconic acid and sorbitol using the immobilized permeabilized cells was carried out. Optimum conditions for continuous operation with the imn~obilized cells were; pH 6.2 and temperature $40^{\circ}C$. Maximum productivities for gluconic acid and sorbitol were about 14.5 g/l/h and 14.8 g/l/h respectively at the dilution rate of 0.075 $h^{-1}$ when 300 g/l each of substrates was fed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.4
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• pp.274-280
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• 2001

This paper presents transconductance (g$\_$m/( characteristics of GaAs MESFET's at high temperatures ranging from room temperature to 350$\^{C}$. GaAs MESFET of 0.3x750[㎛] gate dimension has been used to obtain the experimental data. Gate to source voltage(V$\_$GS/) has been controlled to obtain the temperature dependent characteristics for maximum transconductance g$\_$mmax/ of the device. Furthermore g$\_$mmax/ and expected g$\_$m/ have been traced with temperatures ranging from room temperature to 350$\^{C}$ also by compensating for C$\_$GS/ to maintain the optimum operation of the device. From the results, V$\_$GS/decreases as the operating temperature increases for optimum operation of the transconductance. Finally V$\_$GS/ has been optimized to trace g$\_$mmax/ and enhances the decreased g$\_$m/ with different temperatures.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.5
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• pp.397-403
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• 2017

This paper studies the voltage angle control of interior permanent magnet synchronous motors (IPMSMs). For voltage angle control, the optimum voltage angle trajectory according to the operating speed is researched while the voltage and current limit conditions are considered. Through research, two different optimum voltage angle trajectories that depend on the design of IPMSMs were found. The IPMSM drive based on a voltage angle control that follows such trajectory is proposed. Unlike the conventional voltage angle control method, which is applied only in the flux-weakening region, the proposed voltage angle control can be implemented in all operation ranges from low to high speed. The proposed method is verified by experiments using a DSC controller for 800 W IPMSM.

• The Korean Journal of Food And Nutrition
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• v.6 no.4
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• pp.268-275
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• 1993

The whole cells of Actinoplanes missouriensis KCTC 1780 which produce glucose isomerase was immobillized by flocculation method for the effective production of high fructose syrup using packed-bed bioreactor system. Among the flocculation methods used In this study, the glucose Isomerase activity of flocculated cells using 5% polyethylenimmine and 0.2% glutaraldehyde was the highest as 46.3 unit, and the flocculant was 10.3g(wet weight) per 100m1 of broth, and the residual activity was 92.5%. In the batch operation of glucose isomerization using the flocculated cells, the optimum pH, temperature and isomerization ratio were 7.0, 75$^{\circ}C$ and 31%, respectively. The optimum concentration of Mg2+ which was activator on the glucose isomerization of flocculated cells was 0.1M, and glucose isomerase activity was increased by about 40% compared to none of Mg2+. In the packed-bed bioreactor system with 1.2 hour of residence time at 7$0^{\circ}C$, the reaction stability maintained until 96 hour without toss of activity, and the equilibrium was kept up to 120 hours of the operation.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.1
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• pp.219-229
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• 1994

This paper describes an expert system on the cylindrical grinding operations in order to establish the optimum grinding conditions, which satisfy the maximum removal rates, considering the several constraints of grinding power, workpiece burn, chatter vibration and surface roughness. Specialized knowledge of the grinding operations are acquired from the actual operation database. Coefficientis in the experimental equations are obtaines through the fuzzy regression model based on the fuzzy set theory, and are stored in the actual operation database. The developed system is capable of determining the optimum grinding conditions taking into account some problems, and practical examples of implementaion are described.

• Journal of Biosystems Engineering
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• v.39 no.4
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• pp.299-303
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• 2014

Purpose: This study set out to develop a machine for separating shatter-resistant sesame after threshing. Methods: Three grades of sieve and different blower speeds were tested for a separation system that had been designed specifically for shatter-resistant sesame. Performance tests were run to evaluate the sieve and blower systems in terms of the sesame separation and loss ratios. Results: Tests of the first separation stage using the sieve system revealed the optimum sieve perforation size to be 5 mm. Tests of the second separation stage using the blower system identified the optimum blower speed as being 220 rpm. The optimum separation and loss ratios, of 96.5% and 3.5%, respectively, were obtained at a blower speed of 220 rpm. Conclusions: These results will be useful for the design, construction, and operation of threshing harvesters. For shatter-resistant sesame, an optimum blower speed of 220 rpm was identified.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1199-1202
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• 1993

An Optimum Fuzzy Controller which can be sued to direct the driver to control a running train in an optimum operation way has been developed. In the development process of the controller, the theory and technology of Optimum Control and Fuzzy Control are applied. Practical field tests have been carried out in P.R. of China. In order to make the function of the controller more perfect, the controller is improved by the advanced fuzzy control technology and tool in Japan. The computer simulation of the improved controller has been finished.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.454-457
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• 2005

Voloxidizer for hot cell demonstration that handle spend fuel of high radiation virulence in limited space should become a small size and not scatter in its exit. This study determine optimum velocity of $U_3O_8$ using Newton-Raphson Method. We have conducted fortran programing on the Newton-Raphson Method, obtained a theory results and, predicted optimum velocity on the particle size distribution of $U_3O_8$. We have conducted experimentation using acrylic experimental device for verification of theory method, sampled and analyzed using the particle size analyzer In the results, we have found maximum $5\~7\%$ error rate in the comparative value of theory and experimentation. Optimum velocity and experimental results of $U_3O_8$ for scatter prevention have applied for design of demonstration voloxidizer, and produced operation condition of voloxidizer.

• Journal of Korea Water Resources Association
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• v.30 no.6
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• pp.731-741
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• 1997

Optimum design conditions of rapid mixing impellers for an effective Water Treatment Plant operation were experimentally studied by thorough examination of parameters, such as impeller type and detention time. which govern the removal efficiency of turbidity. It was found that the impeller type is one of the major parameters governing the economic power consumption and the efficiency of turbidity removal. The experimental results showed that not only the velocity gradient G but also a new design guide. so called mixing energy per unit volume of raw water, could be used as a design and operation guides for rapid mixing in W.T.P.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.738-743
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• 1991

A multiobjective analysis technique was applied for the optimum operation of pumps and reservoirs in service water transmission systems. Three major objectives were identified and assessed on the normally operating service water transmission systems. They are, 1) stability of pump operation; 2) economic point of view in minimizing the energy cost for pumping; 3) reliability in meeting the stochasticaly varying demands. The measures of these objectives were required times of pump on-offs in stability, required total energy cost in economics, and minimum required storage during the operating horizon in reliability. In order to find the best meeting solution to the decision maker, a set of non-dominated solutions which show the tradeoff relationships between the considering objectives were generated. The DM selects the best solution from this explicit tradeoff relationships using his heuristic decision rules or experience. The theory was verified by applying to the Kumi Service Water System. A combined technique of the ${\varepsilon}-constraint$ and the weighting methods was used to generate the nondominated solutions, and the dynamic programming algorithm was applied to find the optimal solution for the discretized multi-objective analysis problems.