• Proceedings of the Korean Magnestics Society Conference
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• 2009.05a
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• pp.53-54
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• 2009

• Journal of Korean Society on Water Environment
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• v.24 no.3
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• pp.306-310
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• 2008

Characteristics of microalgal growth was investigated using anaerobic effluent from two-phase animal waste digestor as substrate. Batch experiments were carried out to investigate the effect of the initial nitrogen and phosphorus concentrations on growth of Microcystis aeruginosa, Chlorella sp. and Euglena gracilis. In 400 times diluted anaerobic effluent (TN 3 mg/L), single cell growth of the Euglena gracilis population increased twice without delay, although Chlorella sp. and Microcystis aerugenos take over 144 hours. Similar appearance with single cell growth was observed in mixed cultures. However, microalgae population did not increase under condition of 10 times diluted influent (TP 3 mg/L) in both pure and mixed cultures, which was affected by high organic and nitrogen concentration. Logistic growth model successfully fitted to determine biokinetic parameters such as ${\lambda}$: lag time, ${\mu}m$: maximal specific growth rate, A: asymptote of growth.

• Journal of the Korean Regional Science Association
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• v.13 no.2
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• pp.45-54
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• 1997

A regional economy is characterized as a spatial economy. However the literature shows that it has been treated as a point economy since space is little recognized in regional modeling due to mathematical complication. This leads to the fact that regional model does not sufficiently represent regional characteristic. This paper attempts to construct a regional growth model in a partial equilibrium framework specifically taking into consideration land as a primary factor. The model is formulated largely neoclassical. Labor is assumed to move in response to differences in the wage rate, while capital is perfectly mobile across regions. The paper shows that two growth equilibrium points exist, one stable equilibrium point and the other unstable equilibrium point. The unstable growth equilibrium indicates the existence of minimum threshold that a region must overcome the minimum threshold to grow constantly. Consequently, directions of regional growth are characterized by two growth paths depending on the initial condition of a region. That is to say, a region below the minimum threshold is converging toward the lower stable equilibrium point over time. When a regional economy initially lies above the minimum threshold, it will grow forever. A regional economy is not thus necessarily converging a stationary is not thus necessarily converging a stationary equilibrium point through factor movement. Finally, the impacts of the presence of agglomeration economies and diseconomies are analyzed through the phase diagram. The paper also shows that agglomeration economies result in lowering the minimum threshold and in escalating the level of stable equilibrium However, when agglomeration diseconomies prevail, the results are opposite, i.e., rising the minimum threshold of growth and lowering the growth level of stable equilibrium.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.64-71
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• 2018

This study was conducted to investigate the effects of light intensity and wavelength on the growth of Tetraselmis suecica and Tetraselmis tetrathele. These species were exposed to a blue light-emitting diode (LED; max=450 nm), a yellow LED (max=590 nm), a red LED (max=630 nm) and a fluorescent lamp (three wavelengths). The maximum growth rates (${\mu}_{max}$) of T. suecica and T. tetrathele under a red LED were 1.12/day and 0.95/day, respectively. Under a yellow LED, growth rates were 70% of the values for red wavelength, with low half-saturation constants (Ks). The optimum light source to ensure economically effective and productive growth in a Tetraselmis culture system (Photo-Bioreactor) would thus appear to be a three-phase culture, wherein a yellow LED is used during the lag phase and initial exponential phase to increase growth rate, followed by a red LED during the middle exponential phase to maximize growth rate, and finally a yellow LED again during the late exponential phase and stationary phase to achieve increased yield of useful bioactive substances.

• Journal of Power System Engineering
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• v.8 no.4
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• pp.11-16
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• 2004

In this study, to investigate the effects of omitting low-amplitude cycles from a flight-simulation loading, crack growth tests were conducted on 2124-T851 aluminum alloy specimens. Three test spectra were generated by omitting small load ranges as counted by the rain-flow count method. The crack growth test results were compared with the data obtained from the flight-simulation loading. The experimental results show that the ranges equal to or smaller than 5% of the maximum load do not contribute to crack growth behavior because these are below the initial stress intensity factor range. Omitting these from the flight-simulation loading, test time can be reduced by 54%. However, in the case of omitting the load ranges below 15% of the maximum load, crack growth rates decreased, and crack growth curve deviated from the crack growth data under the flight-simulation loading because loading cycles above fatigue fracture toughness were omitted.

• Journal of Powder Materials
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• v.11 no.2
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• pp.165-170
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• 2004

Growth behavior of two different types of grains, faceted and rounded, in a liquid matrix has been studied in the (75WC-25TiCN)-30Co system. Powder samples were sintered above the eutectic temperature for various times under a carbon saturated condition. (Ti,W)(C,N) grains with a rounded shape and WC grains with a faceted shape coexisted in the same Co based liquid. With increasing sintering time, the average size of (Ti.W)(C,N) grains increased continuously and very large WC grains appeared. The growth of rounded (Ti,W)(C,N) grains followed a cubic law, r^3-r^3_0$=kt, where r is the average size of the grains, $r_0$ the initial average size, k the proportionality constant and t the sintering time. indicating a diffusion-controlled growth. On the other hand, the growth of the faceted WC grains resulted in a bimodal grain size distribution, showing an abnormal grain growth. These observations show that the growth behavior of different types of grains is governed by their shape, faceted or rounded, even in the same liquid matrix.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.2
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• pp.159-166
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• 2016

This study was conducted to examine the effect of IgY supplementation on growth performance, blood metabolism, and disease occurrence in the weaned calves at 3 or 4 month of age. Average daily gain (ADG) and feed intakes were not affected by IgY supplementation, regardless of weaning months. White blood cell (WBC) count of the control group was higher in the final stage than in the initial stage (p<0.05), while that of the IgY supplemented group was lower in the final stage compared to the initial stage (p<0.05). regardless of treatments. Hematocrit (HCT) and red blood cell (RBC) counts were lower in the final stage than in the initial stage (p<0.05), but mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) counts were higher in the final stage than in the initial stage, regardless of treatments. In the control group, concentrations of albumin and globulin were higher in the final stage compared to the initial stage in the weaned calves at 3 month of age (p<0.05), and concentration of blood urea nitrogen (BUN) was increased in the IgY supplemented group. In the control group, concentrations of aspartate aminotransferase (AST) and gamma (${\gamma}$)-glutamyl transferase (GGT) were higher in the final stage compared to the initial stage (p<0.05). In contrast, concentrations of aspartate aminotransferase (AST) and gamma(${\gamma}$)-glutamyl transferase (GGT) were lower in the final stage compared to the initial stage for the IgY supplemented group. A diarrhea calf was only found in the control group. Manure score was higher in the control group compared to IgY supplemented group (p<0.05). Thus, these results indicates that IgY supplementation had positive effects on some blood metabolites, fecal condition score and diarrhea without negative effect on growth performance of the weaned Hanwoo calves.

• KSBB Journal
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• v.20 no.4
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• pp.271-277
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• 2005

The polyunsaturated fatty acids (PUFAs) are mostly synthesized by the marine original microorganisms. In this study, the effect of concentrations of glucose, NaCl, and $MgSO_4{\cdot}7H_2O$ on both the growth and the production of lipid and Docosahexaenoic acid (DHA) was investigated using Thraustochytrium aureum ATCC 34304. $Y_{Lipid/X}\;and\;Y_{DHA/Lipid}$ increased according to the increase of initial glucose concentration until 15 g/L of glucose. The maximum values of $Y_{Lipid/X}\;and\;Y_{DHA/Lipid}$ were 0.18 g/g and 0.41 g/g respectively at 15 g/L of glucose. The biomass yield, $Y_{x/s}$, however, was constant as 0.378 g/g regardless of initial glucose concentrations in the range of 5 g/L to 25 g/L. The specific growth rate of T. aureum increased also with initial glucose concentration from 5 g/L and 15 g/L. The maximum value was $0.79\;day^{-1}$ at 15 g/L of glucose, and the growth rate decreased to $0.57\;day^{-1}$ and remained constant according to initial sugar concentration in the range of higher than 15 g/L of glucose. The concentration of NaCl was changed from 0 g/L to 48 g/L, in order to study the characteristics of the growth and the production of lipid and DHA according to NaCl concentration. The growth and the production of lipid as well as DHA stopped all at 0 g/L of NaCl and the maximum values of all the three variables occurred at 24 g/L. The effect of $MgSO_4{\cdot}7H_2O$ concentration was also investigated not to find the growth and the production of lipid and DHA at 0 g/L. However, the growth and the Production with $MgSO_4{\cdot}7H_2O$ concentration increased to reach the maximum values at 18 g/L of $MgSO_4{\cdot}7H_2O$.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.2
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• pp.63-70
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• 2012

Larix kaempferi and Betula costata seedlings were grown under an elevated temperature ($27^{\circ}C$) for four weeks to understand initial changes on physiological characteristics caused by temperature rising in connection with global warming. At the end of the treatment, growth performance, leaf pigment content, antioxidative enzyme activities and malondialdehyde (MDA) content were measured and analyzed. Relative growth rates of the height of two tree species grown under elevated temperature ($27^{\circ}C$) were lower than those of control ($24^{\circ}C$) and dry weights of leaves, stems and roots were also reduced at higher temperature. Particularly, the root growth reduction of two tree species increased markedly at $27^{\circ}C$ over the study period, which increased the ratio of shoot to root. Under higher temperature, leaf pigment contents decreased, whereas anti-oxidative enzyme activities such as ascorbate peroxidase (APX) and catalase (CAT) increased as compared with the control. But MDA content was not affected by elevated temperature. In conclusion, the elevated temperature leads to root growth reduction, restriction of nutrient uptake from soil and the reduction of leaf pigment contents, which can inhibit the aboveground growth. In addition, higher temperature might act as a stress factor that causes growth reduction through the increase of energy consumption during a growth period.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.155-161
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• 2001

In this study, we analyzed the $NO_X$ removal efficiency and particle size distribution by the pulsed corona discharge process and investigated the effect of several process variables. The NO removal efficiencies and the particle characteristics were measured and analyzed as the function of initial concentrations of NO, $H_2O$, and $NH_3$, applied voltage, pulse frequency and residence time. As the frequency of applied voltage increases, or as the applied voltage increases or as the residence time increases, the NO removal efficiency increases. The change of initial $NH_3$ and $H_2O$ concentrations do not affect the NO removal efficiency significantly. The particle concentration and size increases with the increases of initial NO concentration, residence time and applied voltage.