• Journal of Plant Biology
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• v.27 no.4
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• pp.215-222
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• 1984

The reversal effect of salicylic acid(SA) on inhibition of flowering in Lemna gibba $G_3$ grown on ${NH_4}^+$-free 1/2H medium under continuous light is modified by ${PO_4}^{2-}$- and $Ca^{2+}$ levels. Dimethylsulfoxide(DMSO) either depresses the SA effect in ${NH_4}^{1}$-free 1/2H medium or amplifies it in E medium. The dual action of DMSO determined by relative levels of macro and micronutrient components is discussed.

• Journal of Bio-Environment Control
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• v.7 no.2
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• pp.123-129
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• 1998

This experiment was conducted to composition of nutrient solution for tore of endive hydroponics, and was compared the nutrient solution developed in the Seoul City University(SCUE) with the conventional solution of Proefstation voor Tuinbouw ender Glas. Proper compositions of nutrient solution for endive hydroponics were NO$_3$-N 15.0, NH$_4$-N 1.0, PO$_4$-P 3.0. K 10.0, Ca 5.0 and Mg 3.5 me.$\ell$$^{-1}$ , respectively SCUE and PTG standard nutrient solution showed slightly better yields among nutrient solutions. The SCUE nutrient solution and the PTG nutrient solution had no difference on growth and yield of endive Plants.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.363-369
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• 2009

This experiment was conducted to find out the effect of nutrient solution composition on the growth of cucumber plants and the changes in macro-elements in nutrient solutions in recirculating hydroponic systems. Cucumber plants (Cucumis sativus L. cv. Joeun Baegdadagi) were grown in closed perlite cultivation systems supplied with different nutrient solutions developed by NHRS (National Horticultural Research Station in Japan), Yamasaki, PBG (Proefstation voor Bloemisterij en Glasgroente), and NIHHS (National Institute of Horticultural and Herbal Science in Korea). The concentrations of $NO_{3^-}N$, $Ca^{2+}$, $Mg^{2+}$, and $SO_{4^-}S$ in the recycled nutrient solutions increased but that of $NH_{4^-}N$ decreased gradually in all the treatments. The $PO_{4^-}P$ and $K^+$ concentrations were continuously reduced from the beginning of the harvest to the harvest peak period. There were no significant differences in the concentrations of $NO_{3^-}N$, $NH_{4^-}N$, and $Ca^{2+}$ in the recirculated nutrient solutions among four treatments, while the concentrations of $PO_{4^-}P$ and $K^+$ were lowest and those of $Mg^{2+}$ and $SO_{4^-}S$ were highest in the treatment of Yamasaki's nutrient solution. All growth-related parameters of cucumber plants except for leaf number were not significantly affected by the nutrient solution compositions. Due to its low concentrations of $PO_{4^-}P$ and $K^+$ in the recycled nutrient solution, however, the number and yield of cucumber fruits were lowest in the treatment of Yamasaki's nutrient solution.

• Carbon letters
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• v.16 no.4
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• pp.233-240
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• 2015

Electrochemical synthesis was employed to prepare a novel hydroxyapatite/graphene (HAP/Gr) composite powder suitable for medical applications as a hard tissue implant (scaffold). The synthesis was performed in a homogeneous dispersion containing Na₂H₂EDTA·2H₂O, NaH₂PO₄ and CaCl₂ with a Ca/EDTA/PO₄³⁻ concentration ratio of 0.25/0.25/0.15M, along with 0.01 wt% added graphene nanosheets, at a current density of 137 mA cm⁻² and pH value of 9.0. The field emission scanning electron microscopy and transmission electron microscopy observations of the composite HAP/Gr powder indicated that nanosized hydroxyapatite particles were uniformly placed in the graphene overlay. Raman spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction confirmed graphene incorporation in the HAP/Gr powder. The electrochemically prepared HAP/Gr composite powder exhibited slight antibacterial effect against the growth of the bacterial strain Staphylococcus aureus.

• Journal of the Korean GEO-environmental Society
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• v.16 no.4
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• pp.13-22
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• 2015

The combined impact of Dissolved Organic Matter (DOM) fouling and inorganic ($CaSO_4,Ca_3(PO_4)_2$) scaling on the retention of TNT (2, 4, 6-Trinitrotoluene), RDX (Hexahydro-1, 3, 5-trinitro-1, 3, 5-triazine) and HMX (1, 3, 5, 7-Tetranitro-1, 3, 5, 7-tetrazocane) explosive contaminants by nano-filtration membrane were studied, since organic fouling and salt scaling are the major limitations for membrane filtration. Results reported here indicate that DOM fouling layer with a humic acid does not necessarily lead to an immediate loss of permeate flux but can result in a severe impact on the flux loss when both humic acid and inorganic scaltants were presented simultaneously. The $Ca_3(PO_4)_2$ mixed with humic acid showd most sever flux loss (42%) compared to that of only humic acid presence (8%). It could be a result that the scaling formation of the NF membrane was dominated by cake layer formation of DOM and it was along with pore blocking by the formation of crystals inside the porous active matrix of the NF membrane. In addition, these results indicated that the membrane selectivity of the explosives retention trended correlated with respect to increasing explosives size (listed by MW) based on greater steric interactions and followed the order (MW, g $mol^{-1}$; removal, %): HMX (296.15; 83%) ${\gg}$ RDX (222.12; 49%) ≋ TNT (227.13; 32%). Because the scaling and fouling layer could lead to a additional cake-enhanced concentration polarisation effect, the retention of explosives with the presence of humic acid in the feed solution and inorganic scaling formation on top of an organic fouling layer do not differ substantially retention from that of pure DI feed and NaCl solution.

• KSBB Journal
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• v.10 no.4
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• pp.441-448
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• 1995

Optimized fermentation medium and cultural conditions for the production or exopolysaccharide KS-1 with Bacillus polymyxa KS-1 was following as; 30g g1ucose, 2.59g yeast extract, $2.5g KH_2PO_4, 0.5g NaCl, 0.3g MgSO_4.7H_20, 0.1g CaC0_3 0.05g, FeSO_4.7H_2O, and 0.05g MnS0_4 . 4H_20in 1 liter distilled water. The exopolysaccharide production was influenced by the by the temperature and pH, the optimal conditions for the production of exopolysaccharide KS-1 seemed to be $30^{\circ}C$ and pH 7.0, respectively. About $10.3g/\ell$ of maximum exopolysaccharide was obtained al the initial pH 7.0, $30^{\circ}C$, 2vvm of aeration rate and 400 rpm of impeller speed in a jar fermentor.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.607-615
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• 2016

This research was conducted to investigate the influence of different kinds of acids added to irrigation water containing high levels of bicarbonate on the growth and daughter plant production during the propagation of 'Seolhyang' strawberry. Fertigation solution was prepared with equal concentrations of essential nutrients as found in Hoagland solution, plus $240mg{\cdot}L^{-1}\;HCO_3{^-}$. The concentrations of $HCO_3{^-}$ in the treatment solution were decreased to $60mg{\cdot}L^{-1}$ by the addition of $HNO_3$, $H_3PO_4$, $H_2SO_4$, $HNO_3+H_3PO_4$, or salicylic acid. The mother plants transplanted to raised beds were treated with a specific treatment solution for 126 days and growth and daughter plant productions were monitored. The fresh weight of mother plants in the -control treatment ($240mg{\cdot}L^{-1}\;HCO_3{^-}$) was significantly lower than those in acid containing treatments. The number of daughter plants produced per mother plant was 13 in the -control treatment, but 19.4, 20.1, 18.6, 22.4, and 18.9 in the treatments of $HNO_3$, $H_3PO_4$, $H_2SO_4$, $HNO_3+H_3PO_4$ and salicylic acid, respectively. The substrate pHs after 126 days of treatment were 8.2 and 7.3 in the -control and salicylic acid treatments, respectively, but 5.5, 5.4, 5.3, and 5.5 in the treatments of $HNO_3$, $H_3PO_4$, $H_2SO_4$, and $HNO_3+H_3PO_4$ treatments, respectively. The tissue Ca and Mg contents of mother plants were significantly higher in +control ($90mg{\cdot}L^{-1}\;HCO_3{^-}$) and various acid blending treatments compared to the -control treatment. By contrast, Ca and Mg contents were not significantly different among treatments with acids. The Fe, Mn, Zn, and Cu contents in plant tissue of -control were also significantly lower than those in all other treatments.

• Journal of Environmental Science International
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• v.5 no.5
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• pp.611-617
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• 1996

The effects of nutritional sources on growth of Pseudomonas sp. P2 were investigated in medium containing biphentyl as a carbon source. To determine characterization of Pseudomonas sp. P2, the incubation time was determined to 100 h of the log phase in the growth curve. The optimal compositions for the growth of Pseudomonas sp. P2 degrading polychlorinated biphenyls (PCBs) were 1000 mg/L $NH_4NO_3$, 1000mg/L KH_2PO_4$, 100mg/L MgSO_4$.$7H_2O$, 30mg/L $CaCl_2$.$2H_2O$, 200mg/L NaCl, and 10mg/L $FeSO_4$.$7H_2O$. Pseudomonas sp. P2 showed the degradability of 59.3%, 57.6%, 51.4%, and 48.7% at 500mg/L, 1000mg/L, 1500mg/L, and 2000mg/L of the PCBs within insulating oil after 100 h incubation under the optimum conditions, respectively.

• Journal of Animal Science and Technology
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• v.45 no.5
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• pp.875-884
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• 2003

Operational parameters for struvite crystallization, as a process to recover nitrogen and phosphorus resources from animal wastewater, were studied in this research. Crystallization distinctive of NH$_4$-N and PO$_4$$^{3-}$ in accordance to chemical sources, influent pH, aeration and stirring was examined using 2L of working volume of struvite reactor. Also, to find an effective treatment process combining with electrolysis method, removal characteristics of NH$_4$-N and PO$_4$$^{3-}$ in 6 different processes was tested. As chemical sources for the derivation of struvite formation, MgSO$_4$ and MgCl$_2$ were superior to CaCO$_3$ and CaCl$_2$. From experiment which was conducted to know the effects of aeration and stirring on struvite formation, it was revealed that aeration stimulated the crystallization reaction by inducing faster pH increase. While 90% of P removal was achieved within 1 hour under aeration, 14 hours was consumed under stirring condition. Struvite formation under aeration was affected by influent pH. No crystallization was observed at pH 5 level, but active crystallization reaction was induced over pH 6.0. 95% of P removal by struvite formation at pH 6, 7 and 9 was achieved within 3h, 2h and 10 min., respectively. However, over pH 10, operational problem due to excessive foam formation occurred, and blunting of crystallization reaction was observed at pH 11. When consider the pH range of animal wastewater, pH 7 to 9, efficient struvite formation could be achieved by simple aeration, without any chemical usage for pH adjustment. Among tested processes, the treatment process which electrolyzing the supernatant from struvite reactor, providing air to both reactors, showed best pollutant removal efficiencies. In this combined process, the removal efficiencies of NH$_4$-N and PO$_4$$^{3-}$ was 86% and 98%, respectively, and 92.4% of color removal was obtained.

• Journal of Bio-Environment Control
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• v.14 no.3
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• pp.203-211
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• 2005

The experiment was conducted to investigate the nutrition absorption pattern in the growth stages and develope the optimal nutrient solution hydroponically grown the tomato in closed substrate culture system with the nutrient solution of National Horticultural Research Station in Japan into 1/2S, 1 S, and 2S. When plant was grown in 1/2 S, the growth and yield were high and the pH and EC in the rooting zone were stable. Suitable composition of nutrient solution for tomato was $NO_3-N$ 7.1, $PO_{4}$-P 2.1, K 4.0, Ca 3.1, Mg 1.2, and $SO_{4}-S\;1.2\;me{\cdot}L^{-1}$ in the early growth stage and $NO_3-N$ 6.5, $PO_4-P$ 2.3, K 3.4, Ca 3.1, Mg 1.1, and $SO_4-S\;1.1\;me{\cdot}L^{-1}$ in the late growth stage by calculating a rate of nutrient and water uptake. To estimate the suitability for the nutrient solution of tomato in a development of optimum nutrient solution of tomato developed by Wonkwang university in korea (WU), plant was grown in perlite substrate supplied with different solution and strengths(S) by research station for greenhouse vegetable and floricultuin in the Netherlands (Proefstation voor tuinbouw onder glas te Naaldwijk; PTG) of 1/2 S, 1 S and 2 S, respectively, The growth was good at the PTG and WU of 2 S in early growth stage, and at the WU 2S in late growth stage. The highest yield of tomato obtained in the WU of 2 S, although blossom-end rot was appeared in all treatments. pH and EC in root zone of WU of 2 S were stable during the early and late growth stage. Therefore when plant was grown in WU of 2 S, N and P content in the nutrient solution need to low, according N and P content of their leaves were high in WU of 2 S.