• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2729-2732
• /
• 2008

Cylindrical film-cooling hole is formulated numerically and optimized to enhance film-cooling effectiveness. The Kriging method is used an optimization technique with Reynolds-averaged Navier-Stokes analysis of fluid and heat transfer with shear stress transport model. The hole length-to-diameter ratio and injection angle are chosen as design variables and spatially averaged film-cooling effectiveness is considered as objective function which is to be maximized. Twelve training points obtained by Latin Hypercube Sampling for two design variables. Optimum shape shows the film-cooling effectiveness increased.

• Plant Resources
• /
• v.8 no.2
• /
• pp.91-95
• /
• 2005

In spring, to determine the optimal planting date and plant density of rapeseed in southern areas of Korea. $Taiwan^{\#1}$ variety for spring sowing, the highest yielding variety was grown under five different planting date and plant density. Yield components such as plant height, ear length, number of seedling stand per $m^2$, number of per ear and seed set percentage were highest at the plots with Mar. 5 of planting date and 50/20cm drilling of plant density. Yield of seed, oil, gas and 1,000 grains weight and erucic acid content were highest at the Mar. 5 of planting date and 50/20cm drilling of plant density. Judging from the results reported above, at optimum planting date and plant density of rapeseed seemed too be Mar. 5 of planting date and 50/20cm plant density in spring sowing.

• Plant Resources
• /
• v.8 no.2
• /
• pp.171-174
• /
• 2005

This study was conducted to investigate the effect of activated carbon on leaf and stem production of Agastache rugosa as affected by different amounts of activated carbon. The results obtained are summarized as follows. Growth characteristics including plant height and leaf length were the highest when activated carbon added with $10\%$, suggesting that optimum amount of activated carbon was ranged from 10 to $20\%$. Growth and enlargement of the root were improved by $10\%$ AC. Activated carbon can be utilized as a soil conditioner in agricultural crop areas.

• Plant Resources
• /
• v.8 no.3
• /
• pp.225-229
• /
• 2005

This study was conducted to investigate the effect of activated carbon on leave production of Allium tuberosum. Growth characteristics including plant height and leaf length were the highest when activated carbon was added with 5%, suggesting that optimum amount of activated carbon was ranged from 5 to 10%. Weight of fresh green vegetable in Allium tuberosum was low in control. And fresh weight of Allium tuberosum was higher in 5% treatment of activated carbon. However, when the plants were grown in activated carbon of $5{\sim}10%$, fresh yield of green vegetable of Allium tuberosum can be increased by using Activated Carbon. Activated carbon can be utilized as a soil conditioner in agricultural crop areas.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.14 no.1
• /
• pp.73-82
• /
• 2002

A small refrigeration system used in a water purifier was tested by employing propane/isobutane (R-290/R-6OOa) mixtures as an alternative refrigerant of R-12. The drop-in tests were performed by varying mass fraction of propane at 0.25, 0.5 and 0.75 with a change of both refrigerant charge amount and capillary tube length in order to find an optimum composition in aspect of performance and reliability of the system. As a result, the mixture of 50% propane-50% isobutane showed the best performance and reliability among them in a small refrigeration system. During steady state operations, both the COP and refrigeration capacity increased by 4% and 9%, respectively, as compared to the baseline R-12 system. In addition, the propane/isobutane (50/50) mixture system yielded advantages in the minimization of modification and redesigning of system components due to very similar saturation tempera- ture and pressure characteristics with R-12.

• Plant Resources
• /
• v.8 no.1
• /
• pp.67-70
• /
• 2005

To determine the optimal fertilizer level of wanggol in southeren areas of Korea, Gwangsan ealy local, the highest yielding variety was grown under nine different fertilezer levels. Yield components such as stem length, number of tillers, stem diameter were the highest at the treatments of fertilizer levels, $N-P_{2}O_{5}-K_{2}O=7-2-3$ and 9-2-3 kg/10a plots. Dry cortex and medulla yield were the highest at the treatments of $N-P_{2}O_{5}-K_{2}O=7-2-3$ and 9-2-3 kg/10a fertilizer levels. Judging from the results, an optimum fertilizer level of wanggol seemed to be $N-P_{2}O_{5}-K_{2}O=7-2-3$ and 9-2-3 kg/10a.

• Plant Resources
• /
• v.8 no.1
• /
• pp.71-74
• /
• 2005

Activated carbon(AC) can be utilized as a soil conditioner in agricultural crop areas. This study was conducted to investigate the effect of AC on Leaf and Stem Production of Angelica acutiloba as affected by different amounts of AC. The results obtained are summarized as follows. Growth characteristics including plant height and leaf length were the highest when activated carbon added with 10, suggesting that optimum amount of activated carbon was ranged from 10 to $20\%$. Growth and enlargement of the root were improved by $10\%$ AC.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.41 no.5
• /
• pp.541-550
• /
• 1992

The fourth harmonic conversion(FHC) efficiency of high-power Nd laser pulse with wavelength of 1.054x10S0-6Tm using two KDP crystals(doubler adn quadrupler) was simulated numerically. Simulation results show that for the perfect phase-matching condition the FHC efficiency were 60-70% for several hundreds MW/cmS02T class and over 70% for GW/cmS02T class laser pulses. And the overall characteristics of FHC were discussed in terms of effects of input intensity, crystal length, and mismatch angle Δ$\theta$. Optimum method to FHC was type-II doubler & type-I quadrupler KDP crystal because type-II KDP doubler crystal has wide tolerance of acceptance matching-angle.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.53 no.8
• /
• pp.463-468
• /
• 2004

This paper was applied space harmonic method as a characteristic analysis technique for slotless PMLSM. There is advantages of active response to the change of design parameters as well as reduction of the calculation time. The method can be overcome disadvantages of finite element analysis that needs long times calculation, repetitions of pre and post-process. In this paper, 3D-space harmonic method was applied to consider the precise description of end turn coil shape and the changes of characteristic according to changes of length of z-axis direction. The thrust of optimal design was performed using genetic algorithm to enhance the thrust which is the disadvantage of slotless type PMLSM. For design parameters, width of permanent magnet, width of coil, width of coil inner and lengths of z-axis direction were selected. For objective functions. thrust per weight. thrust per volume. multi-objective function was selected.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 1999.11a
• /
• pp.120-123
• /
• 1999

This paper presents the design method of EMC(Electromagnetic Coupling) microstrip array antenna for CS(Communication Satellite) system. Microstrip dipole antennas are attractive elements owing to the desirable properties such as simplicity, small size and linear polarization. From the optimum simulation results by the FDTD method[1], design parameters such as EMC dipole length, width, height and offset are discussed at 12CHz. The array characteristics of 5-elements and 10-elements array are also presented. By adjusting geometry of model antenna, we can design dual polarization EMC microstrip dipole antenna for CS system. Direction of nam beam is easily tilted by the control of distance between dipole elements.