• Journal of Environmental Science International
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• v.21 no.1
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• pp.105-111
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• 2012

The effects of substrate size on the growth of microphytobenthos Achnanthes sp., Amphora sp., Navicula sp. and Nitzschia sp. were examined using glass beads in order for phytoremediation in the benthic layer of coastal waters. The glass beads used in this study were 0.09~0.15 mm (G.B 1), 0.25~0.50 mm (G.B 2), 0.75~1.00 mm (G.B 3) and 1.25~1.65 mm (G.B 4). No addition of glass bead used as control. The specific growth rate and maximum cell density of four microphytobenthos species were increasing with decreasing size of glass beads. Moreover, the control experiment without added attachment substrates showed the lowest specific growth rate and maximum cell density. Therefore, the suitable attachment substrates for mass culture of microphytobenthos seems to be important in order for phytoremediation using microphytobenthos.

• The Journal of Korean Medicine
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• v.16 no.1 s.29
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• pp.370-378
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• 1995

In order to consider the clinical efficacy of moxa combustion, understand the quality and quantity of heat stimulation and get the basic data for the development of electric moxibustion apparatus, the pattern of combustion temperature was measured by size of moxa(small, medium, large and maximum size). The results were as follows. 1. The pattern of combustion temperature by moxa burning was classified into input period, consisting of preheating and heating periods, and output period, consisting of heat retaining and cooling periods, in all experimental groups. But it was difficult to observe the preheating period in small sized moxa. 2. It was inclined that the more moxa size was large, the more the heating and heat retaining periods were long and the maximum temperature was high. The characteristics of moxa combustion is primarily by the rate of combustion temperature, gradient temperature and duration of combustion, and their correlation among these factors and their clinical effects in practice.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2760-2765
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• 2009

Pfair scheduling algorithm, which is an optimal scheduling algorithm in the hard real-time multiprocessor environments, is based on the fixed quantum size. Recently, several methods that determine the maximum quantum size dynamically were proposed in the mode change environments. But these methods considered the case in which the period of a task can only be decreased. In this paper, we consider the case in which the period of a task can be decreased or increased, and propose an improved method that determine the maximum quantum size dynamically in the mode change environments. A simulation shows that the proposed method is effective.

• Journal of Environmental Health Sciences
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• v.29 no.2
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• pp.45-49
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• 2003

In this study, lots of methods have been studing to utilize energy and decrease contaminated effluents. There has been great progress on IGCC (Integrated gasification combined cycle) to reduce thermal energy losses. The following results have been conducted from desulfurization experiments using waste shell to remove H$_2$S. According to TGA results, temperature had influenced on H$_2$S removal efficiency. As desulfurization temperature increased, desulfurization efficiency increased. Also, maximum desulfurization efficiency was observed at 80$0^{\circ}C$. Desulfurization was related to calcination temperature. Considering temperature ranges of exhausted gas from hot gas gasification equipment were 400~80$0^{\circ}C$. Thus, desulfurization efficiency would be increased desulfurization temperature situation at highly. Experiments by TGA showed that particle size of sorbents had influenced on desulfurization capacity. Maximum desulfurization capacity was observed at 0.631 mm for oyster and clam. Rest of sorbents showed similar capacity within 0.171~0.335 mm particle size range. So, particle size would be considered. When would be used waste shells as IGCC sorbents. According to the results about desulfurization capacity by TGA, oyster had the best desulfurization capacity among limestone and waste shell. We would be identify to substituted oyster for existing sorbents

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.2
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• pp.7-11
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• 1996

The size of pupil with pupillary light reflex is determined by the amount of a luminance. and it is dependent with the distribution function of the retinal illuminance which is the amount of transmittance for the external light due to the size of pupil, and the detector of cone and rod due to the amount of the luminance. The change of the pupil size with the luminance can be expressed with the mathematical model $$y(x)={\alpha}+{\beta}\frac{1}{1+{e}{x}{p}(x-x_0)/{\theta}}$$ where ${\alpha}$ is the size of the pupil diameter in a maximum value of the luminance, ${\beta}$ is the deviation of the pupil's diameter between maximum and minimum, ${\theta}$ is the parameter showed the degree of a sensitivity. Comparing with the experimental value of P.Moon et al, We known that the equation of the model is very compatible.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.3
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• pp.130-135
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• 2012

In this paper, we propose a technique to detect the size and location of the small target in images by using Gaussian kernel repeatedly. In order to detect the size and location of the small target, we find the local maximum value by applying the facet model and then use the $3{\times}3$ Gaussian kernel repeatedly. we determine the size of small target by comparing the local maximum value $D_2$ according to the number of iteration. To reduce the computational complexity, we use the Gaussian pyramid when using the kernel repeatedly. Through the experiment, we verified that the size and location of the small target is detected by the number of iterations and results show improvements from conventional methods.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.608-618
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• 2005

A new technique giving significant drag reduction in turbulent shear flows has been proposed by using the buoyancy effect to generate periodic spanwise motion. Such spanwise motion can be obtained by arranging heating and cooling strips periodically aligned in the spanwise direction of a vertical channel, where the streamwise mean flow is perpendicular to the gravity vector The strip size has been changed in order to obtain the optimum size corresponding to the maximum drag reduction. The bulk Reynolds number, $ Re_{m} = U_{m} \delta / \nu \$ is fixed at 2270 while Grashof numbers is changed between $10^{6}$ to $10^{7}$. As Grashof number increases, considerable drag reduction can be obtained, At the highest Grashof number, an optimum strip size of about 250 wail units gives drag reduction of about 35$\%$. The greater the Grashof number, the smaller the strip size attains the maximum drag reduction.

• Journal of Powder Materials
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• v.11 no.2
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• pp.137-142
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• 2004

In this study, chemical solution mixing and hydrogen reduction method was used to fabricate nanostructured $Fe_xCo_{1-x}$ alloy powders. Fe-Co chloride mixture, FeCl$_2$ and COCI$_2$ with 99.9％ purity, were reduced in hydrogen atmosphere. Nanostructured Fe-Co alloy powders with a grain size of 50 nm were successfully fabricated. Magnetic properties of fabricated $Fe_xCo_{1-x}$(x=0, 10, 30, 50, 70, 100) alloy powders with the same grain size were measured because size factor can affect magnetic properties. Coercivity of Fe-Co alloy powders were increased with increasing Co contents. Maximum value of coercivity in various Co contented Fe-Co alloy powders with similar grain size was 125 Oe at Fe$_{100}$. Saturation magnetization value at Fe$_{70}$Co$_{30}$ composition showed maximum value of 219 emu/g and saturation magnetization value decreased with increasing Co contents and minimum value of 155 emu/g was observed at Co$_{100}$.

• Journal of Welding and Joining
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• v.10 no.3
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• pp.54-62
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• 1992

Large steel water pipes are joined prevalently by bell and method and welded at inside and outside of lapped parts. According to the Korean Standard(KS) for fabrication of water pipes, the weldments are designed to have the length of leg which is same as or larger than the thickness of the pipe. It is recently pointed out that the standard size of weldments is too large, which results in an excessive consumption of material and labor. In this study, several cases of weldments having different sizes were investigated to reduce the length of leg to the effective size. For each case, the analysis of stresses was carried out to evaluate the safety of the welded pipes by using a package program, ANSYS, under the consideration of the loading condition of water pipes which includes the soil pressure on the pipe, the load over the road, and temperature change of the pipe. The results of this study revealed that the weldment which has the length of leg of the size over 0.7*thickness of the pipe could provide a stress level below the yield strength. Especially when the length of leg is 85% of the wall thickness, the maximum equivalent stress is only slightly higher than that of the leg of fillet of the size of 1.0*pipe thickness.

• ETRI Journal
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• v.45 no.6
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• pp.996-1006
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• 2023

Renewable energy is promoted massively to overcome problems that fossil fuel power plants generate. One popular renewable energy type that offers easy installation is a photovoltaic (PV) system. However, the energy harvested through a PV system is not optimal because influenced by exposure to solar irradiance in the PV module, which is constantly changing caused by weather. The maximum power point tracking (MPPT) technique was developed to maximize the energy potential harvested from the PV system. This paper presents the MPPT technique, which is operated on a new high-gain voltage DC/DC converter that has never been tested before for the MPPT technique in PV systems. Fuzzy logic (FL) was used to operate the MPPT technique on the converter. Conventional and adaptive perturb and observe (P&O) techniques based on variables step size were also used to operate the MPPT. The performance generated by the FL algorithm outperformed conventional and variable step-size P&O. It is evident that the oscillation caused by the FL algorithm is more petite than variables step-size and conventional P&O. Furthermore, FL's tracking speed algorithm for tracking MPP is twice as fast as conventional P&O.