• Journal of Korean Society of Forest Science
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• v.95 no.6
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• pp.735-742
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• 2006

The objective of this study was to elucidate the tolerance of woody plants to simulated acid rain in relation to mycorrhizal inoculation. Germinating seedlings of Robinia pseudoacacia were planted in 1I pots with autoclaved soil mixture of vermiculite, sand and nursery soil at 1:1:1 ratio. Each pot was inoculated with both crushed root nodules from a wild tree of the same species and commercial arbuscular mycorrhizal inoculum of Glomus intraradices at the time of planting the seedlings. Simulated acid rains at pH 2.6, 3.6, 4.6, and 5.6 were made by mixing sulfuric acid and nitric acid at 3: 1 ratio. Each pot received nutrient solution without N and P, and was also supplied with 180 ml of the one pH level of the acid rains once a week for 50 days. The plants were grown in the green house. At the end of experimental period, plants were harvested to determine contents of chlorophyll, mineral nutrients and net photosynthesis in the tissues, dry weight of the plants, and mycorrhizal infection in the roots. Mycorrhizal infection rate was significantly reduced only at pH 2.6, which meant vitality of G intraradices was inhibited at extremely low pH. Height growth, dry weight production, nodule production and chlorophyll content were increased by mycorrhizal infection in all the pH levels except pH 3.6. Particularly, mycorrhizal inoculation increased root nodule production by 85% in pH 5.6 and 45% in 4.6 treatments. But the stimulatory effect of mycorrhizal inoculation on nodule production was reduced at pH 3.6 and 2.6. Net photosynthesis was increased by mycorrhizal infection in all the pH levels. The phosphorus(P) content in the tissues was increased by 43% in average by mycorrhizal inoculation, which was statistically significant except in pH 2.6. It was concluded that mycorrhizal inoculation of Robinia pseudoacacia would enhance growth and resistance of the plants to acid rain by improving the photosynthesis, phosphorus nutrition, and more nodule production.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.97-104
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• 2020

The present study conducted mock-up tests under the simulated sewage environments to examine the practical significance and limitation of coating materials that were previously developed on the basis of the bacterial glycocalix as a protection of concrete structures exposed to microbiological and sulphate attacks. The variations of the compressive strength and mass of the concrete due to the sulphate attack were measured using cylinder specimens. The bacteria growth and glycocalix formulation were calculated from the samples extracted from the sewage pipes. The next generation sequencing analysis was also conducted for environmental damage assessment due to the use of Rhodobacter capsulatus in the simulated sewage environments. The mock-up tests revealed that the developed coating materials have a good potential in resisting the sulphate attack, indicating no reduction on compressive strength and mass of the coated concrete under the sewage environment. At the age of 91 days, the concentrations of viable bacteria and glycocalix measured from the hardened coating materials were 1.4×10⁴cell/mL and 67.5mg/㎤, respectively. Moreover, harmful strains were not observed in the sewage water including glycocalix-coated concrete pipes. This implies that Rhodobacter capsulatus used in the coating materials does not influence negatively the microorganism cluster in the sewage environments.

• Korean Journal of Materials Research
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• v.16 no.4
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• pp.225-230
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• 2006

Nanoimprint lithography (NIL) is a novel method of fabricating nanometer scale patterns. It is a simple process with low cost, high throughput and resolution. NIL creates patterns by mechanical deformation of an imprint resist and physical contact process. The imprint resist is typically a monomer or polymer formulation that is cured by heat or UV light during the imprinting process. Stiction between the resist and the stamp is resulted from this physical contact process. Stiction issue is more important in the stamps including narrow pattern size and wide area. Therefore, the antistiction layer coating is very effective to prevent this problem and ensure successful NIL. In this paper, an antistiction layer was deposited and characterized by PECVD (plasma enhanced chemical vapor deposition) method for metal stamps. Deposition rates of an antistiction layer on Si and Ni substrates were in proportion to deposited time and 3.4 nm/min and 2.5 nm/min, respectively. A 50 nm thick antistiction layer showed 90% relative transmittance at 365 nm wavelength. Contact angle result showed good hydrophobicity over 105 degree. $CF_2$ and $CF_3$ peaks were founded in ATR-FTIR analysis. The thicknesses and the contact angle of a 50 nm thick antistiction film were slightly changed during chemical resistance test using acetone and sulfuric acid. To evaluate the deposited antistiction layer, a 50 nm thick film was coated on a stainless steel stamp made by wet etching process. A PMMA substrate was successfully imprinting without pattern degradations by the stainless steel stamp with an antistiction layer. The test result shows that antistiction layer coating is very effective for NIL.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.1
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• pp.25-32
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• 2007

We investigated the silicide reaction stability between 10 nm-Col-xNix alloy films and silicon substrates with the existence of 4 nm-thick natural oxide layers. We thermally evaporated 10 nm-Col-xNix alloy films by varying $x=0.1{\sim}0.9$ on naturally oxidized single crystal and 70 nm-thick polycrystalline silicon substrates. The films structures were annealed by rapid thermal annealing (RTA) from $600^{\circ}C$ to $1100^{\circ}C$ for 40 seconds with the purpose of silicidation. After the removal of residual metallic residue with sulfuric acid, the sheet resistance, microstructure, composition, and surface roughness were investigated using a four-point probe, a field emission scanning electron microscope, a field ion bean4 an X-ray diffractometer, and an Auger electron depth profiling spectroscope, respectively, to confirm the silicide reaction. The residual stress of silicon substrate was also analyzed using a micro-Raman spectrometer We report that the silicide reaction does not occur if natural oxides are present. Metallic oxide residues may be present on a polysilicon substrate at high silicidation temperatures. Huge residual stress is possible on a single crystal silicon substrate at high temperature, and these may result in micro-pinholes. Our results imply that the natural oxide layer removal process is of importance to ensure the successful completion of the silicide process with CoNi alloy films.

• Journal of Life Science
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• v.23 no.9
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• pp.1079-1087
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• 2013

Speed germination success and robust vegetative growth of citrus rootstock through improved sowing methods and fertilizer inputs offer the usage of root system for the citrus. The current study evaluated the influence of seed coat removal and different fertilizer concentrations on plant germination and plant growth of spontaneous rootstock siblings. Decoated and coated seeds of diploid and tetraploid plants were sown in tubes. Commercial fertilizer concentrations of 0, 2, 4, 6, 8 and $10g{\cdot}l^{-1}$ were added. The experimental layout followed a randomized block $2{\times}6$ factorial design (seed coat removal ${\times}$ fertilizer concentration) for each rootstock. Fertilizer concentrations were 0, 10, 20 and $30g{\cdot}l^{-1}$ of the fertilizer for the resistance of the strength on the salt level. The germination rate of seeds without testa sown in vitro was improved (67-80%) compared to that of nontreated seeds. The eventual tree height of the seeds without testa in the diploid group was increased due to higher fertilization compared to that in the nontreated group. The removal of seed testa promoted the seed germination of both diploid and tetraploid trifoliate orange and resulted in greater height. Their vegetative development was also increased due to the increased fertilization of the rootstock. The Fv/Fm value for the diploid plants was 0.4 and 0.8 for the tetraploid ones under salt stress after 11 days of treatment. The removal of seed testa may improve the seed germination of trifoliate orange. Tetraploid trifoliate orange appears to possess resistance to salt stress compared to the diploid variety.