• Journal of the Speleological Society of Korea
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• no.71
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• pp.1-4
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• 2006

Chloromethylnaphthalene is a valuable compound for obtaining of the plant growing stimulator - -napthylacetic acid. Chloromethylation of naphthalene by paraformaldehyde in the presence of glacial acetic acid, phosphoric and hydrochloric acids at temperature 80 - 85C and duration - 6 hours the -chloromethylnaphthalene yield was 55-57%. Using Box-Wilson method for mathematical planning of experiment carried out optimization of its synthesis for purpose increasing -chloromethylnaphthalene yield. Preliminary, one - factor experiments were carried out for selecting independence main parameters influencing on the synthesis. A full factor experiment of 23 with extended matrix of planning was used for optimization. Aiming to increase the -chloromethylnaphthalene yield, the obtained mathematical model was used for program of sharp raising on the reply surface. The received optimal conditions for the -chloromethylnaphthalene synthesis were selected as following: molar ratio of naphthalene parapfsormaldehyde of 1 : 2 temperature - 105C duration of the reaction - 3 hours. The yield of -chloromethylnaphthalene under these optimal conditions was 75%.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.3046-3054
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• 2013

Synthesis of Carbon Nanotube bundles has been achieved by simple and economical solvothermal procedure at very low temperature of $180^{\circ}C$. The product yield obtained was about 70-75%. The optimization of reaction conditions for an efficient synthesis of CNTs has been presented. The CNTs are obtained by reduction of hexachlorobenzene in the presence of Na/Ni in cyclohexane. The X-ray diffraction, Fourier transform infrared and Raman spectral studies have inferred us the graphene structure of the products. The CNTs formed as the bundles were viewed on scanning electron microscope, transmission electron microscope and high-resolution transmission electron microscope. These are the multiwalled CNTs with outer diameter of 5-10 nm, the inner diameter 2-4 nm and cross sectional diameter up to 5 nm. Brunauer-Emmett-Teller (BET) based $N_2$ gas adsorption studies have been made to obtain BET surface area and $H_2$ storage capacity. Effect of the experimental variables such as reaction temperature, amount of catalyst and the amount of carbon source were investigated. It is found that they affect significantly on the product nature and yield.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.4
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• pp.378-385
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• 2004

Viscous-driven pumping is a very promising type in microscale applications. However, there exist a few disadvantages such as low efficiency and small volume flow rate. In the present study, a pump with tandem rotating cylinders and its optimum synthesis are proposed fur enhancing pumping performance. First, using an unstructured grid CFD method, we investigate the effects of geometrical parameters and then the performance of the pump with tandem cylinders is evaluated. Next, an optimum design synthesis tool is constructed by combining the aforementioned CFD analysis model with the mathematical optimization model, namely, Modified Method of Feasible Directions (MMFD). This technique is used to optimize the geometrical parameters of the pump, fur maximizing pumping efficiency. From the optimization results, it is believed that the present optimum synthesis is robust and has a potential fur other microfluidic device design.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05a
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• pp.36-37
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• 2004

$\alpha$-Chloromethylnaphthalene is a valuable compound for obtaining of the plant growing stimulator - $\alpha$-napthylacetic acid. Chloromethylation of naphthalene by paraformaldehyde in the presence of glacial acetic acid, phosphoric and hydrochloric acids at temperature 80-85$^{\circ}C$ and duration - 6 hours the $\alpha$-chloromethyl-naphthalene yield was 55-57%. Using Box-Wilson method for mathematical planning of experiment carried out optimization of its synthesis for purpose increasing $\alpha$-chloromethylnaphthalene yield. Preliminary, one - factor experiments were carried out for selecting independence main parameters influencing on the synthesis. A full factor experiment of 2$^3$with extended matrix of planning was used for optimization. Aiming to increase the $\alpha$-chloromethylnaphthalene yield, the obtained mathematical model was used for program of sharp raising on the reply surface. The received optimal conditions for the $\alpha$-chloromethylnaphthalene synthesis were selected as following: molar ratio of naphthalene - parapfsormaldehyde of 1 : 2; temperature -105$^{\circ}C$; duration of the reaction -3 hours. The yield of $\alpha$-chloromethylnaphthalene under these optimal conditions was 75 %.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.4
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• pp.165-174
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• 2000

This paper presents the application of H$\infty$ control synthesis using LMI optimization method to power system stabilizer(PSS) design. Since power system is usually operated under circumstance of unmeasurable uncertainties and external disturbances, the improvement of small signal stability becomes one of the most important issue for securing system stability and preventing low frequency oscillation phenomena. The LMI optimized H$\infty$ PSS provides robust performance and guarantees the internal stability under these operating conditions. The global optimal H$\infty$ norm is found using LMI convex optimization method which is more systematic than standard two Riccati solution method. The design results are simulated for a case study. We verified that the LMI method shows the best performance characteristic smong standard Riccati method and conventional lead/lag method.

• The Journal of the Acoustical Society of Korea
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• v.41 no.6
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• pp.637-646
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• 2022

Sub-arrays of arbitrary conformal array have different geometric shape through steering direction, thus the beam patterns of sub-arrays are always non-uniform. In this paper, we apply the beam pattern synthesis method using convex optimization into the conformal array, and shows the improvement of uniformity of beam performance. The simulation is performed with the conformal array of cut-sphere shape. As a result, the standard deviation of 3 dB beamwidth in elevation is greatly reduced but the directivity index is also reduced. To alleviate this trade-off, we propose a convex optimization using a shading function.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.459-459
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• 2003

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.888-888
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• 2009

A simulation study on SCR (Steam Carbon dioxide Reforming) process in gas-to-liquid (natural gas to Fischer-Tropsch synthetic fuel) process was carried out in order to find optimum reaction conditions for GTL (gas-to-liquid) process reaction. Optimum SCR operating conditions for synthesis gas to FT (Fischer-Tropsch) process were determined by changing reaction variables such as feed temperature and pressure. During the simulation, overall synthesis process was assumed to proceed under steady-state conditions. It was also assumed that physical properties of reaction medium were governed by RKS (Redlich-Kwong-Soave) equation. SCR process was considered as reaction models for synthesis gas in GTL proess. The effect of temperature and pressure on SCR process $H_2$/CO ratio and the effect of reaction pressure on SCR reaction were mainly examined. Simulation results were also compared to experimental results to confirm the reliability of simulation model. Simulation results were reasonably well matched with experimental results.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.1
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• pp.74-84
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• 1991

This paper presents an algorithm for technology-dependent logic optimization and technology mapping, and describes a performance-driven logic synthesis system, SILOS, implemented based on the proposed algorithm. The system analyzes circuits and resynthesizes the critical sections such that generated circuit operates opertes within time constraints, using only gate types supported by library for direct implementation. Experimental results show that the system can be a viable tool in synthesizing high-performance logic circuits.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.8
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• pp.56-63
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• 1995

A new method is presented for the synthesis of lossy tapered transmission line having presecribed frequency characteristic in the passband. The theory of lossy case extends lossless cases suggested by Klopfenstein and others, and a special optimization process based on the Fourier transfrom pair and generalized Taylor's procedure is proposed for exact designs of frequency-dependent and distance-dependent lossy tapered line. The process is achieved by control of zero points of lobe-like input reflection coefficient. The validity of the suggested method is confirmed by synthesizing a lossy microstrip transformer and analyzing the simulation results.