• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.6
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• pp.19-26
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• 2010

Batch experiments were conducted to investigate growth and nutrient removal performance of microalgae Chlorella vulgaris by using piggery wastewater in different concentration of pollutants and the common growth models (logistic, Gompertz and Richards) were applied to compare microalgal growth parameters. Removal of nitrogen (N) and phosphorus (P) by Chlorella vulgaris showed correlation with biomass increase, implying nutrient uptake coupled with microalgae growth. The higher the levels of suspended solids (SS), COD and ammonia nitrogen were in the wastewater, the worse growth of Chlorella vulgaris was observed, showing the occurrence of growth inhibition in higher concentration of those pollutants. The growth parameters were estimated by non-linear regression of three growth curves for comparative analyses. Determination of growth parameters were more accurate with population as a variable than the logarithm of population in terms of R square. Richards model represented better fit comparing with logistic and Gompertz model. However, Richards model showed some complexity and sensitivity in calculation. In the cases tested, both logistic and Gompertz equation were proper to describe the growth of microalgae on piggery wastewater as well as easy to application.

• Journal of Industrial Technology
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• v.39 no.1
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• pp.7-14
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• 2019

Carbon nanotubes (CNT) on metal substrates are definitely beneficial because they can maintain robust mechanical stability and high conductivity between CNT and metal interfaces. Here, we report direct growth of CNT on Ni-based superalloy, Inconel 600, using thermal chemical vapor deposition (CVD) with acetylene feedstock in the growth temperature range of $400-725^{\circ}C$. Furthermore, we studied the effect of substrate pretreatment on the growth yield enhancement and growth temperature decrease of CNT on Inconel 600. Activation energy (AE) for CNT growth was estimated from the CNT height change with respect to the growth temperature. The AE values significantly decreased from 205.03 to 24.35 kJ/mol by the pretreatment of thermal oxidation of Inconel substrate at $725^{\circ}C$ under ambient. Higher oxidation temperature tends to have lower activation energy. The results have shown the importance of pretreatment temperature on CNT growth yield and growth temperature decrease.

• Journal of Ginseng Research
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• v.19 no.2
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• pp.181-187
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• 1995

Cylindvocarpon destmtalns isolate CY-92-01, pathogen of root-rot of Panax ginseng showed t the maximum mycelial growth on the Czapek solution agar among the thirteen kinds of media. Five isolates (Isolate CY-92-01, CY-92-03, CY-92-07, CY-94-01, CY-94-02) of C. destructan from various growth stages of p. ginseng recovered from several geographical sites also showed maximum growth in the Czapek-Dox broth compared with potato dextrose broth and V-8 juice broth. Rapid growth rate was maintained until 12 days after inoculation on the Czapek-Dox broth and mycelial weight was somewhat constant until 20 days. After 30 days of incubation, the mycelial weight began to decrease. The fungal growth occurred from 5$^{\circ}C$ to $25^{\circ}C$ and optimum temperature for growth was 2$0^{\circ}C$. Mycelial weight orderly decreased at 15, 25, 10, and 5$^{\circ}C$. Quantitative measurement was impossible at 5$^{\circ}C$. No fungal growth was occurred at the temperature higher than 3$0^{\circ}C$. Growth was observed at all tested pH ranges from 2.8 to 8.0. Optimum pH for growth was 4.0~5.0 followed by pH 3.3~3.5 and 5.4~6.0. The least growth occurred at pH 2.8.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.6
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• pp.558-562
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• 1999

For 6H-SiC crystals which was obtained by sublimation growth, the formation of micropipes and internal planar defects was discussed in consideration of the inter-relationship between mass adsorption behavior and the defects origin on the growth interface on the basis of KSV theory and the the step growth pattern on the vicinal plane. Micropipes and planar defects was formed in the region which the step could not be grown by impurities impinging. It was realized that the internal defects formation was related to the crystallographic step planes formed on the growth interface and the migration of the molecules adsorbed on it.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.5
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• pp.191-194
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• 2008

We will focus on the horizontal Bridgman growth system to analyze the transport phenomena numerically, because the simple furnace system and the confined growth environment allow for the precise understanding of the transport phenomena in solidification process. In conventional melt growth process, the dopant concentration tends to vary significantly along the crystal. In this work, we propose the modification of crucible geometry for improving the productivity of silicon single-crystal growth by controlling axial specific resistivity distribution. Numerical analysis has been performed to study the transport phenomena of dopant impurities in conventional and proposed Bridgman silicon growth using the finite element method and implicit Euler time integration. It has been demonstrated using mathematical models and by numerical analysis that proposed method is useful for obtaining crystals with superior uniformity along the growth direction at a lower cost than can be obtained by the conventional melt growth process.

• The Korean Journal of Ceramics
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• v.2 no.4
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• pp.221-225
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• 1996

In diamond synthesis by metal film growth method under high pressure and high temperature, the nucleation and growth of diamond was observed dependent on the carbon source variation from graphite powder to the heat treated powders of lamp black carbon. At the low driving force condition near equilibrium pressure and temperature line, nucleation of diamond did not occur but growth of seed diamond appeared in the synthesis from lamp black carbon while both nucleation and growth of diamond took place in the synthesis from graphite. Growth morphology change of diamond occurred from cubo-octahedron to octahedron in the synthesis from graphite but very irregular growth of seed diamond occurred in the synthesis from lamp block carbon. Lamp black carbon transformed to recrystallized graphite first and very nucleation of diamond was observed on the recrystallized graphite surface. Growth morphology of diamond on the recrystallized graphite was clear cubo-octahedron even at higher pressure departure condition from equilibrium pressure and temperature line.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.1
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• pp.1-5
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• 2001

SiC single crystals were grown in the various condition of growth pressure and temperature in the sublimation growth. We observed the growth step morphology and the shapes on the surface of as-grown crystals using an optical microscope, and characterized the co-relations among the growth parameters by adapting the Burton, Carbera and Frank theory(BCF theory)for nucleation and crystal growth.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.3
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• pp.293-300
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• 1996

A continuous growth method (Orr's method) were developed to grow LiNbO3 single crystals. The optimum growth condition established are as follows; When the controlled temperature of a platinum crucible were 1190℃∼1210℃, the pulling rate was 2 mm/hr, the feeding rate was 1.5∼2.5 g/hr, and the rotation speed was 20 rpm. The phase and growth orientation of the grown LiNbO3 crystals wer characterized by a X-ray diffraction method. The overflowing phenomena, which induced cracking into the grown crystal during the process, was effectively suppressed by the control of the growth parameter.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.2
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• pp.50-57
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• 2004

Mercurous Bromide ($Hg_2Br_2$) crystals hold promise for many acousto-optic and opto-electronic applications. This material is prepared in closed ampoules by the physical vapor transport (PVT) growth method. We investigate the effects of solutal convection on the crystal growth rate in a horizontal configuration for diffusive-convection conditions and purely diffusion conditions achievable in a low gravity environment. Our results show that the growth rate is decreased by a factor of one-fourth with a ten reduction of gravitational acceleration near y = 2.0 cm. For 0.1 $g_O$ the growth rate pattern exhibits relatively flat which is intimately related to diffusion-dominated processes. The growth rate nonuniformity is regardless of aspect ratio across the interfacial positions from 0 to 1.5. Also, the effect of a factor of the ten reduction in the gravitational acceleration is same to both Ar = 5 and 2. The enlargement in the molecular weight of B from 50 to 500 by a factor 4 causes a decrease in the maximum growth rate by the same factor, indicative of the effect of solutal gradients.

• Korean Journal of Ecology and Environment
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• v.40 no.4
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• pp.520-526
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• 2007

To select submerged macrophytes to suppress growth of Microcystis aeruginosa through releasing allelochemicals, we conducted growth experiments with water from patches of submerged macrophytes and with aqueous extracts of those submerged macrophytes. In the first experiment, growth rates of M. aeruginosa decreased as biomass of Myriophyllum spicatum and Hydrilla verticillata increased. In the second experiment, M. aeruginosa showed approximately 50% growth reduction with extracts from M. spicatum and 24% reduction with extracts from Ottelia alismoides. Both M. aeruginosa growth experiments with water and plant extracts suggest that M. spicatum would be the best candidate to reduce M. aeruginosa growth.