• Clean Technology
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• v.17 no.4
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• pp.325-328
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• 2011

Atom-efficient preparation of 9, 9'-bis[4-(2'-hydroxy-3'-acryloyloxypropoxy) phenyl]fluorene (3), the extensively used building block for fluorene-containing acrylic epoxy polymers has been described. The epoxide ring opening esterification of 9, 9-bis[4-(glycidyloxy)phenyl]fluorene (1) with acrylic acid was catalyzed by some onium salts such as quaternary ammonium and phosphonium salts. While the coupling reactions depend greatly on the kind of the onium salts, the reaction of 9, 9-bis[4-(glycidyloxy)phenyl]fluorene (1) with acrylic acid proceed most efficiently in the presence of a catalytic amount of tetrabutylphosphonium bromide at $110^{\circ}C$ with 90% yield. This reaction is a cleaner reaction that minimizes the use of reactants and the production of chemical wastes.

• Polymer(Korea)
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• v.28 no.4
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• pp.344-351
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• 2004

Poly(ethylene glycol)-based diblock and triblock polyester copolymers stimulating to temperature were studied as injectable biomaterials in drug delivery system because of their nontoxicity, biocompatibility and biodegradability. We synthesized the diblock copolymers consisting of methoxy poly(ethylene glycol) (MPEG) (M$_{n}$=750 g/mole) and poly($\varepsilon$-caprolactone) (PCL) by ring opening polymerization of $\varepsilon$-CL with MPEG as an initiator in the presence of HCl . Et$_2$O. The aqueous solution of synthesized diblock copolymers represented sol phase at room temperature and a sol to gel phase transition as the temperature increased from room temperature to body temperature. To confirm the in vivo gel formation, we observed the formation of gel in the mice body after injection of 20 wt% aqueous solution of each block copolymer. After 2 months, we observed the maintenance of gel without dispersion in mice. In this study, we synthesized diblock copolymers exhibiting sol-gel phase transition and confirmed the feasibility as biomaterials of injectable implantation.n.

• Korean journal of applied entomology
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• v.25 no.3 s.68
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• pp.159-167
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• 1986

White tip nematode damage to rice was surveyed at 111 $My{\check{o}}n$ from 36 Gun in Kyongsangnam-Do, $Ky{\check{o}}ngsangbuk-Do\;and\;Ch{\check{o}}llanam-Do$. Rate of damaged stem by the nematode was highest at $Ch'angny{\check{o}}ng-Gun\;in\;Ky{\check{o}}ngsangnam-Do$ as 28.3%, $Y{\check{o}}ngch'on-Gun\;in\;Ky{\check{o}}ngsangbuk-Do$ as 69.3% and $Pos{\check{o}}ng-Gun\;in\;Ch{\check{o}}llanam-Do$ as 40.6%. In pot experiment, no white tip symptoms were appeared in Tongil hybrids except $W{\check{o}}np'ung$ by 3.4% but a great number of the nematode was detected in seeds while symptom and a fair amount of the nematode were observed in Japonica cultivars. The number of nematode in Shingwang cultivar of Tongil hybrids and Dongin cultivar of Japonica was highest by 1997, by 1023 individuals per 10g of seed respectively. Detection rate of the nematode was different depended upon peeling of the husks. Less than 50% was detected from unhulling seed compared with hulled seed except 8 cultivars such as $Shins{\check{o}}nchal$, Hangangchal, $S{\check{o}}gwang,\;Y{\check{o}}ngpung$, Milyang 23, $Such{\check{o}}ng,\;Taech'{\check{o}}ng\;and\;S{\check{o}}nam$. More effective detection was oftained with temperature level at $25^{\circ}C$ and increased with immersing time regardless of peeling the husks.

• Korean Journal of Environmental Agriculture
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• v.1 no.2
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• pp.129-133
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• 1982

This study was conducted to find out the resistance of rice varieties to ozone gas. Thirty eight rice varieties were exposed to 0.3 ppm $O_3$ gas for 3 hours. Damage symptom, percentage of destroyed leaf and chlorophyll contents were observed after $O_3$ fumigation. The results obtained are as follows. 1) Typical symptom of $O_3$ damage appeared to greyish subtle spots in Japonica type and redish brown subtle spots in Indica-Japonica hybrid type within rice leaf vein. 2) Resistant varieties to $O_3$ gas were Palgwangbyeo, Seokwangbyeo and Milyang 30, while sensitive ones were Gwanakbyeo, Jinjubyeo and Hankangchalbyeo. 3) Chlorophyll damage of rice leaves were higher in Nongbaeck, Dobongbyeo, Palgeum, Jinjubyeo than in Milyang 21, Podgwangbyeo, Josaeongtongil, Honamjosaeng, Hwanggeumbyeo. 4) The amount of chlorophyll damage showed highly significant positive correlation with that of leaf destruction.

• Polymer(Korea)
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• v.38 no.4
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• pp.510-517
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• 2014

A series of polyimide (PI) was prepared by reacting 4,4'-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA) as the anhydride and bis(3-aminophenyl) sulfone (APS), bis[4-(3-aminophenoxy)-phenyl] sulfone (BAPS), 2,2-bis(4-aminophenyl)-hexafluoropropane (6FPD), 2,2-bis[4-(4-aminophenoxy)-phenyl]hexafluoropropane (6FBAPP), 2,2'-bis(trifluoromethyl)benzidine (TFDB), or 1,4-phenylenediamine (PDA) as the diamine. Residual stress behaviors were detected in-situ during thermal imidization of the polyimide precursors using a thin film stress analyzer (TFSA), and interpreted with respect to their morphology. According to the molecular orientation and packing order, the residual stress varied from 23.1 to 12.5 MPa, decreased with increasing chain rigidity. The thermal properties of the PI films were investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and thermomechanical analysis (TMA). Their optical properties were measured by ultraviolet-visible spectrophotometer (UV-vis), and spectrophotometry. The properties of PI films were found to be strongly dependent upon the morphological structure. However, trade-offs between residual stress and optical properties were identified.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.1
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• pp.26-32
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• 1985

Ten recommended rice varieties were cultivated in paddy area affected by air-pollutants and in normal area to select varieties adaptable to air-pollution environment. Rice plants grown in pollution site showed higher contents of total sulfur and fluorine in leaf through the whole growing period compared with those in non-pollution site, and rice leaves destroyed by air-pollutants were found only in pollution site. Rice grain yield and four yield components of ten rice varieties grown in pollution site were lower than those in normal area. Five rice varieties among ten were selected as adaptable to air-pollution environment, based on their yielding potential in pollution site and grain yield ratio between two sites. Rice varieties adaptable to pollution showed little variation of percent ripened grains and number of panicles per hill between two sites. Chlorophyll content in flag leaf of rice plants grown in pollution area was lower than in non-pollution area. No relationship was found between grain yield ratio (pollution/non-pollution site) of ten varieties and total sulfur content ratio, fluorine content ratio, chlorophyll content ratio between two sites, and percent destroyed leaf in pollution site, respectively. This result suggest that varietal adaptability to air-pollution environment is not related with the amount of pollutants absorbed, but with the degree of response to pollutants.

• Polymer(Korea)
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• v.25 no.1
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• pp.98-107
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• 2001

Dielectric properties and shape memory characteristics of SBS composites filled with carbon black as conductive filler and (Ba,Ca)$(Sn,Ti)O_3$ or $SrTiO_3$ as dielectrics were investigated for the development of phantom model. SBS/carbon black composite showed an increment of complex dielectric constant with increasing the content of carbon black and the frequency dependence that the dielectric constant decreases with the frequency. The complex dielectric constant and the conductivity of SBS/carbon black/dielectrics composites increased with the increase of dielectrics and the characteristics of the frequency dependence also occurred by the effect of carbon black. Phantom materials with the dielectric properties and the conductivity corresponding to human tissues for the measurement of specific absorption rate(SAR) within the frequency range of current mobile phones(775MHz~2GHz) could be developed by adjusting the composition ratios of carbon black, dielectrics and SBS and by controlling the characteristic of frequency dependence of composite. From thermomechanical cycling test good shape recoverability could be obtained in SBS composite even though the residual strain was increased by the effect of filler.

• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.242-252
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• 1985

In order to get information on the ecology of rice false smut, germination ability and pathogenicity of sclerotia and chlamydospores of the pathogen, environmental conditions affecting the disease outbreak and varietal resistance have been investigated. 1. The degree of outbreak of rice false smut was higher in the upland rice in comparison with the paddy field rice in respect to the number of affected grains per ear, the size and weight of smut balls formed on affected grains as well as the ratio of sclerotial formation produced on smut balls. 2. Germination percentage and days required for germination of overwintered sclerotia placed on the soil surface in July were 81% and 19 days, respectively, while those of overwintered sclerotia treated in May were 60-70% and 41 days. Sclerotia placed on the soil surface or under 1 cm depth of the soil surface and incubated at $25-30^{\circ}C$ were germinated well, whereas those placed under 3 cm or 5 cm depth of the soil surface were not germinated at all. Germinability and stroma productivity of sclerotia were reduced when the sclerotia were cutted into small pieces. 3. The average number of stroma formed on a sclerotium was six and that of perithecia formed in a stroma was about 50 to 140. 4. Percentage of germination of chlamydospores on the yellow balls was very high and was decreased as the color of the balls being darken with maturation. 5. Panicle of rice plants were successfully infected by injection inoculation with suspention of ascospores and chlamydospores of the pathogen to the sheaths at the booting stages, while seeding infection by spraying with suspensions of chlamydospores was unsuccessful. 6. More number of infected grains was distributed on basal parts of an affected ear than that of infected ones distributed upper parts of the ear, when the affected ear was divided into five parts from its basal portion to the apical of the ear. 7. The occurrence of the disease was more severe in the late maturing varieties of rice in comparison with the early maturing varieties. 8. When the level of nitrogen applied was increased, the incidence of disease increased, and the infection percentage of the disease was increased as the transplanting date was delayed. 9. The weight of panicles and 1000 kernels and the ratio of ripenness were reduced, and the contamination degree of grains with chlamydospores were increased as the number of smut balls per panicle were increased.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.50-57
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• 1985

An attempt was made to determine the optimum levels of sewage sludge application for seogwangbyeo in the farmer's field. 1. Optimum amount of sewage slude application was 338kg/11a at the fertilizer (N-P-K) level of 15-10-10kg/10a, 430kg/10a at that of 7.5-10-10kg/10a and 544kg/10a at no fertilizer. 2. Number of tillers during all growing period were increased with amounts of sewage sludge and/or chemical fertilizers. 3. Panicles per hill was increased but percent ripeness was decreased with the application of increasing level of sewage sludge and/or chemical fertilizer. In particular, the decrease of ripeness among yield-related components sotood out as an important one to be solved for higher yield. 3. Panicles per hill was increased but percent ripeness was decreased with the application of increasing level of sewage sludge and/or chemical fertilizer. In particular, the decrease of ripeness among yield-related components stood out as an important one to be solved for higher yield. 4. Ripeness was remarkably decreased in high nitrogen content of soil and rice plant under heavy amounts of sewage sludge and/or chemical fertilizer. 5. Ripeness that had direct effect on yield showed significantly possitive correlation with the content of $SiO_2$ and $SiO_2/N$ in rice plant from 25 days after transolanting to harvesting stage. 6. Maximumutillzation of nitrogen and its production efficiency of absorbed nitrogen in sewage sludge were 16.6% and 31.9kg (Yield/kg, N) at the level 15-10-10kg/10a as fertilizer with amounts of sewage sludge application, and 19.0% and 31.8kg (yield/kg, N) at sewage sludge application without fertilizer.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.3
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• pp.111-121
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• 2013

Accurate prediction of sea water temperature has been emphasized to make precise local weather forecast and to understand change of ecosystem. The Yellow Sea, which has turbid water and strong tidal current, is an unique shallow marginal sea. It is essential to include the effects of the turbidity and the strong tidal mixing for the realistic simulation of temperature distribution in the Yellow Sea. Evaluation of ocean circulation model response to vertical mixing scheme and turbidity is primary objective of this study. Three-dimensional ocean circulation model(Regional Ocean Modeling System) was used to perform numerical simulations. Mellor- Yamada level 2.5 closure (M-Y) and K-Profile Parameterization (KPP) scheme were selected for vertical mixing parameterization in this study. Effect of Jerlov water type 1, 3 and 5 was also evaluated. The simulated temperature distribution was compared with the observed data by National Fisheries Research and Development Institute to estimate model's response to turbidity and vertical mixing schemes in the Yellow Sea. Simulations with M-Y vertical mixing scheme produced relatively stronger vertical mixing and warmer bottom temperature than the observation. KPP scheme produced weaker vertical mixing and did not well reproduce tidal mixing front along the coast. However, KPP scheme keeps bottom temperature closer to the observation. Consequently, numerical ocean circulation simulations with M-Y vertical mixing scheme tends to produce well mixed vertical temperature structure and that with KPP vertical mixing scheme tends to make stratified vertical temperature structure. When Jerlov water type is higher, sea surface temperature is high and sea bottom temperature is low because downward shortwave radiation is almost absorbed near the sea surface.