• Journal of Plant Biology
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• v.19 no.1
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• pp.1-6
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• 1976

This study was carried out to investigate the formation of precipitates between lead ion and the essential anions of plants, the effects of lead concentration on seed germination and plant growth in water and soil culture, and the germinating and growing recovery of inhibited seed germination and plant growth by lead. Four kinds of the seeds (Glycine max M., Triticum vulgare V., Setaria viridis (L) P. De Beauvois, and Digitoria sanguinalis (L) Scopoli var) were germinated and growth in water and soil culture included the different concentrations of lead for five days. The seeds and plants inhibited germination and growth by lead were transferred to lead free Hoagland solution and the growing recovery was observed. The precipitates of lead ion were observed in the solution of both acidity and alkalinity included each anion of $H_2PO_4^-, HPO_4^{2-}, PO_4^{3-}, SO_4^{2-} and MoO_4^{2-}$ in a room temperature, whereas the precipitates between lead ion and other anions were observed largely in the solution of alkalinity, so that it seemed that lead could be remained in the state of non-soluble in plant and soil. The inhibition of germination and growth in the water culture was observed in 100ppm of lead, whereas the inhibition in the case of the soil culture was observed in 10000ppm of lead. The difference of the effected concentration between water and soil culture in germination and the growth was 100 times. When the seed and plant inhibited the growth in 5000ppm or 10000ppm of lead for five days were transferred to lead free Hoagland solution, the recovery of germination and growth was observed in three days. This growing recovery was different according to the kinds of plant and concentrations of lead. It seemed that plant growth could be inhibited by the inhibition of the metabolism concerned with the precipitates between lead iion and other anions.

• Korean Journal of Organic Agriculture
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• v.14 no.4
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• pp.411-420
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• 2006

Indole-3-acetic acid (IAA) biosynthesis by bacteria occurs widely in rhizospheres. Bacterial species able to synthesize IAAmay be exploited for beneficial interactions in crop management systems. The objective of this study was to determine the response of ivyleaf morningglory (Ipomoea hederacea) seedlings to IAA and to an IAA-producing rhizobacterum, Bradyrhizobium japonicum isolate GD3. IAA solution and isolate GD3 suppression of seedling growth measured as radicle length and biomass depended on IAA concentration. Seedling radicle length was significantly reduced by ca. 29% with more than $1.0{\mu}M$ of IAA solution, compared to the control, 48 h after application. The cell concentration at 50% growth reduction ($GR_{50}$) of the seedling radicle was IAA production by isolate GD3 at $10^{4.82}\;cfu$, the cell concentration for 50% growth reduction ($GR_{50}$) of seedling radicle was 0.24 iM, which was much lower than the IAA solution concentration ($117.48{\mu}M$) required for $GR_{50}$. Therefore, excess IAA production by isolate GD3 may be more detrimental to morningglory radicle growth than standard IAA solution. Results confirmed involvement of IAA in suppressive effects of isolate GD3 on morning-glory seedlings grown in a hydroponic system.

• Journal of the Korean Ceramic Society
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• v.46 no.6
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• pp.596-601
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• 2009

Double-layered ZnO nanostructures have been synthesized by aqueous solution method on (001) plane of ZnO nanorod. A stepwise changing of aqueous solution concentration gave rise to a new nano-structured layer consisting of either multiple of nanorods or nanowires with much smaller radii than that of the ZnO nanorod on which the new layer was grown. As the first step the ZnO nanorods have been grown to have the (001) preferential orientation in the aqueous solution consisting of 0.1M zinc nitrate and 0.1 M HMT. This preferentially aligned ZnO nanorods have been regrown in either a less diluted solution of 0.01M zinc nitrate and 0.01 M HMT or a more diluted solution of 0.005M zinc nitrate and 0.01 M HMT. A new nano-layer consisting of numerous aligned nanorods or nanowires has been produced on the (001) planes of ZnO nanorods. The growth mechanism for this double layered ZnO nanostructure is ascribed to the (001) polar surface energy instability and inhibition of (001) plane growth due to the step-wise change of aqueous solution concentration; ZnO nuclei formed on the (001) plane grow preferentially in (010) plane instead of (001) plane to reduce the total surface energy. Surface area of ZnO nanostructure can be increased in orders of magnitudes by forming a new layer consisting of smaller nanorods/nanowires on (001) plane of ZnO nanorods.

• Journal of the Korean Ceramic Society
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• v.56 no.6
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• pp.589-595
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• 2019

The top-seeded solution growth (TSSG) method is an effective approach for the growth of high-quality SiC single crystals. In this method, the temperature gradient in the melt is the key factor determining the crystal growth rate and crystal quality. In this study, the effects of the aperture at the top of the hot-zone on the growth of the SiC single crystal obtained using the TSSG method were evaluated using multiphysics simulations. The temperature distribution and C concentration profile in the Si melt were taken into consideration. The simulation results showed that the adjustment of the aperture at the top of the hot-zone and the temperature gradient in the melt could be finely controlled. The surface morphology, crystal quality, and polytype stability of the grown SiC crystals were investigated using optical microscopy, high-resolution X-ray diffraction, and micro-Raman spectroscopy, respectively. The simulation and experimental results suggested that a small temperature gradient at the crystal-melt interface is suitable for growing high-quality SiC single crystals via the TSSG method.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.1
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• pp.8-13
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• 2016

A top-seeded solution growth (TSSG) is a method of growing SiC single crystal from the Si melt dissolved the carbon. In this study, multiphysics modeling was conducted using COMSOL Multiphysics, a commercialized finite element analysis package, to get analytic results about electromagnetic analysis, heat transfer and fluid flow in the Si melt. Experimental results showed good agreements with simulation data, which supports the validity of the simulation model. Based on the understanding about solution growth of SiC and our set-up, crystal growth was conducted on off-axis 4H-SiC seed crystal in the temperature range of $1600{\sim}1800^{\circ}C$. The grown layer showed good crystal quality confirmed with optical microscopy and high resolution X-ray diffraction, which also demonstrates the effectiveness of the multiphysics model to find a process condition of solution growth of SiC single crystal.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.2
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• pp.240-247
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• 2002

Recently, a thermal energy storage system has been developed actively fur the purpose of saving energy and reducing the peak electrical demand. Especially, ice slurry is a promising working fluid for low temperature energy storage systems. A flow of ice crystals has a large cooling capacity as a result of the involvement of latent heat. However, there are still problems related to the recrystallization of ice crystals for realizing long term storage and long distance transportation. To find improvements fur this, a method for the creation of ice crystals resistant to recrystallization has been proposed and researched by the use of an antifreeze protein (AFP) solution etc. In the present study, it has been investigated the growth of ice crystal in several kinds of water solution added non-ionic surfactant. The results shows that size of ice crystal was smaller with increasing in added surfactant. And ice crystal was not increased with added surfactant.

• Journal of Ocean Engineering and Technology
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• v.7 no.2
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• pp.131-140
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• 1993

To study the corrosion fatigue begavior of T.M.C.P. steel, the rotary bending fatigue test with the change of concentration of NaCl solution was carried out. Fatigue life in the corrosion environment is decreased markedly in comparision with that in the air. Fatigue limit in the air was about 225 MPa. In case of 3.5% NaCl solution fatigue life could be expressed as .sigma./sub f/=10,392 * (N/sub f/)/sup -o.2923 . According to the paris's rule, crack growth rates could be expressed as da/dN=2.62.*10/sup -7/ .DELTA. K/sup 1.09/(3.5% NaCl solution), da/dN=1.95 *10/sup -7 .DELTA. K/sup 1.05/(1% NaCl solution), da/dN=2.62 * 10/sup -7/.DELTA./sup 0.72/(0.01% NaCl solution) with da/dN expressed in mm/cycle and .DELTA.K in MPa.GAMMA.m. The crack growth rate in the corrosion environment was highest under 3.5% NaCl solution.

• Korean Journal of Organic Agriculture
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• v.12 no.4
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• pp.427-436
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• 2004

This study was conducted to investigate the effect of microbial product on microorganisms in soil and the growth of leaf lettuce. The test material were treated with chitosan, wood vinegar and EM activity liquid, and treatment concentration was 50 times solution and 100 times solution level with foliar application. The results were summarized as follows : Among foliar application of microorganisms treatments diluted by chitosan 100 times solution level was effective considering growth of leaf lettuce as compared other dilutions and control plot. Change of microorganism number in the soil for cultivation of chinese cabbages and leaf lettuce was increased with microorganism treatment plot as compared with control plot. Specially chitosan 100 times solution level showes the most significant effect.

• Korean Journal of Environment and Ecology
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• v.7 no.1
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• pp.6-9
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• 1993

To examine aluminum toxicity on woody plants, Forsythia koreans and Platanus occidentalis cuttings were grown in the pot(48$\times$33$\times$9cm) filled with sand, and treated aluminum solution and ground water (pH 6.75) 3times per week from April 28, 1993 to June 16. Aluminum solution were prepared 1.0, 2.5 and 5.0mM aluminum potassium sulfate, dilulted with ground water. Growth-related characters (Shoot growth, leaf number and leaf chlorophyll content ) and root growth were measured and compared among the treatments. In all growth-related characters(Shoot growth, leaf number and leaf chlorophyll content), differences among the treatments were highly significant. In root growth, differences among the treatments were highly significant for Forsythia koreana cuttings, but not for Platanus occidentalis cuttings.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.277-283
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• 1997

The effect of nutrient concentration and plant growth regulators on rooting of Coleus stem cuttings were investigated. In contrast to sand cutting, the nutrient solution or plant growth regulator treatment increased the root numbers and root length. The concentration of nutrient solution were 1, l/2 and 1/4 strength of the balanced nutrient solution developed by Japanese Horticultural Experimental Station and the highest root growth was obtained from 1/4 strength nutrient concentration. NAA or IBA treatment in culture solution stimulated the rooting and 0.01mg/l of NAA or IBA was effective in root development. Furthermore, days for rooting were shortened and root growth were promoted by mixing nutrient solutions with plant growth regulators and by using cutting with leaves. The rooting of Coleus was observed under microscope and the adventitious root formation initiated at 3 days after cutting with nutrient and auxin mixture.