• Korean Journal of Environment and Ecology
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• v.25 no.4
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• pp.540-561
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• 2011

We carried out a study for ecological management and ideal vegetation structure selection on the shrine forest of 'Miwhang-sa' considering the species diversity and the vegetation structure analysis associated with global warming. We carried out the analyses of phytosociological vegetation structure, correlation between vegetation units and environmental variables, life form, species diversity, and species evenness. This study identified the vegetation units as 3 communities. The identified vegetation units are as follows: Quercus acuta community(DQ), Quercus serrata-Quercus variabilis community(QQ) and Celtis sinensis community(CS). According to the basis on the environmental variables; Ca, Mg and P, Celtis sinensis community and other communities were classified. Quecus serrata-Quercus variabilis comm. and Quercus acuta comm. were classified, according to the basis on the environmental variables; organic matter(OM), Ni and Zn. Sasa borealis as life form R1-2, dominated the herb layer and will dominate the herb and shrub layers. Species simplification is formed on herb layer and will be formed on shrub layer. The species diversity of Quercus serrata-Quercus variabilis community is higher than the one of Quercus acuta community, and the species diversity of shrine forest around Miwhang-sa was higher than the shrine forest around Nameun-sa where evergreen broad-leaved forests dominate. It is essential that the long-term vegetation management considering the vegetation units by phytosociological analysis, the species simplification problem of low layers by S. borealis and the species diversity and evenness in the shrine forest, Miwhang-sa.

• Journal of the Korea Organic Resources Recycling Association
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• v.32 no.2
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• pp.27-35
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• 2024

It was known that crude oil can be mainly divided into saturates, aromatics, resins, and asphaltenes. If microbial biodegradation of asphaltenes is effectively viable, additional oil production will be expected from depleted oil reservoir. Meanwhile, biodegradation can be applied to other aspects, such as the bioremediation of spilled oil. In this case, the biodegradation of asphaltenes also plays an important role. It has been already reported that asphaltenes are decomposed by bacterial consortia. However, the biodegradation mechanism of asphaltenes has not been clearly presented. The major reason is that the molecular structure of asphaltenes is complicated and is mainly in a aggregated form. In this paper, it was presumed that the biodegradation process of asphaltenes may follow the microbial oxidation mechanism of saturates and aromatics which are easier biodegradable than asphaltenes among the crude oil components. In other words, the biodegradation process was explained by serial stages; the contact between asphaltenes and bacteria in the presence of biosurfactants, and the decomposition of alkyl groups and fused-rings within the asphaltene structure.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.297-297
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• 2006

Recently columnar liquid crystals have been studied due to their possible application to organic conducting materials. Supramolecular columnar liquid crystals consist of mesogenic unit which can aggregate into discs that will make up the columns which associate to form a two-dimensional network. In this study, we prepared supramolecular columnar liquid crystals containing hydrogen bonding between carboxylic acid and, pyridine moieties. Thermal and structural properties of prepared complexe were investigated, and it exhibited hexagonal columnar structure ($Col_{h}$) at room temperature.

• Journal of Photoscience
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• v.9 no.2
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• pp.353-355
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• 2002

We prepared 3-(1-hydroxyethyl)-bacteriopyrochlorophy11-a (3) possessing magnesium atom and phytyl ester from modification of natural bacteriochlorophyll(BChl)-a. A dichloromethane solution of (3$^1$R) and (3$^1$S)-3 was diluted with 100~1000 fold volume of cyclohexane to give new species absorbing near-infrared lights. The resulting Q, maximum of (3$^1$R)-3 was 860 nm and red-shifted by 2150 $cm^{-1}$ / from the monomeric. In the nonpolar organic solvent, epimeric (3$^1$S)-3 showed a 1ess red-shifted peak at 798 nm as well as a residual monomeric band. Such visible spectra indicated that 3 diastereose1ectively aggregated in cyclohexane to afford oligomers possessing a simi1ar supramolecular structure with chlorosomal aggregates of natural BChl-d, 7,8-dehydro-form of 3.

• Macromolecular Research
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• v.8 no.5
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• pp.209-214
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• 2000

Polyenaminonitriles containing cycloaliphatic and aliphatic units were prepared by interfacial or solution polymerization reaction of p-bis(1-chloro-2,2-dicyanovinyl) benzene (1) with 4-aminobenzyl-amine, 1-(2-aminoethyl)piperazine, 2-(aminomethyl)pyrrolidine and 4-(aminomethyl)piperidine. The chemical structure of the polymers was confirmed through a syntheses of the model compound. The resulting polymers possessed inherent viscosities of 0.29∼0.62 dL/g and they were easily soluble in polar aprotic solvents and common organic solvents. Thermal properties of the polymers such as curability and stability were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and infrared spectroscopy. The polymers exhibited a large exotherm in DSC analyses and underwent a curing reaction around 340-370$\^{C}$ to form insoluble materials. The polymers showed 70-80% residual weight at 600 $\^{C}$ under nitrogen.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.83-86
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• 1998

Ferroelectric PZT(40/67)/PZT(60/40)heterolayered thin films were Prepared by the alkoxide-based Sol-Gel method. PZT(40/60) and PZT(60/40) stock solutions were made and spin-coated on the P7Ti/Si02/Si substrate alternately. These PZT(40/60) and PZT(60/40) films were dried at 300$^{\circ}C$ for 30min to remove organic materials and were sintered at 650$^{\circ}C$ for 1 hour to crystalize into a perovskite structure. The coating and heating procedure were repeated 6 times to form heterolayered films. Increasing the number of coating, coercive field was decreased. The relative dielectric constant, loss, remanent polarization and coercive field of the 4-coated PZT heterolayered were 1200, 4.1[%], 30.794[${\mu}$C/㎡] and 147.22[kV/cm], respectively.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.51-51
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• 2012

Cellulose is extremely difficult to dissolve cellulose in water and most common organic solvents due to their stiff molecular structure, close chain packing and intermolecular hydrogen bonds. Recently, cellulose solutions using ionic liquids (ILs) as a green solvent have been known to form cholesteric liquid crystalline phase at high cellulose concentration. In this study, the phase transition and rheological behaviors of concentrated cellulose/[AMIM]Cl solution were investigated using polarized optical microscopy and rheometry. Studies were conducted to characterize the influence of cellulose concentration on the phase transition of the cellulose solution and the mechanical properties of the regenerated fibers spun from the anisotropic cellulose/[AMIM]Cl solutions.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.287-287
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• 2006

Amphiphilic random copolymers can form various types of micelles in aqueous media depending on the balance between two opposite interactions- electrostatic repulsion and hydrophobic attraction. This balance can change by addition of some organic solvent to the aqueous solution, and as a result, we can control the micellar structure and micellization equilibrium by changing the solvent content. In the present study, we have investigated the micellization equilibrium of an amphiphilic statistical copolymer consisting of sodium 2-(acrylamido)-2- methylpropanesulfonate and hexyl methacrylate in mixtures of water and methanol by sedimentation equilibrium and fluorescence.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.303-303
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• 2011

Orderings and electronic structures of organic molecules on metal substrates have been studied due to possible applications in electronic devices. In molecular systems, delocalized pi-electrons play important roles in the adsorption behaviors and electronic structures. We studied the adsorption and electronic structures of Co-Porphyrin molecules on Au(111) using scanning tunneling microscopy (STM) and spectroscopy (STS) at low temperature. Molecules form closely packed two-dimensional islands on Au(111) surface with two different types, having different shape evolutions in our energy-dependent STM observations. The Kondo resonance state, occurred by spin exchange interaction between the Co center atom and conduction electrons in the metal substrate, was observed in one type, while it was absent in the other type in scanning tunneling spectroscopy measurements. Possible origins of two molecular shapes will be discussed.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1142-1146
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• 1996

Cholesterol-containing surfactant was synthesized, and it was sonicated with monomer in water to form a vesicle solution. This vesicle solution was dried to construct a membrane which had a molecular multilayer structure. Using UV irradiation the monomer in this membrane were polymerized, and then surfactant was extracted by organic solvent. Using a X-ray diffractometer, the thickness of one layer and the regularity of the multilayer were measured. And scanning electron microscopy was conducted for fractured polymer film.