• Journal of Conservation Science
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• v.32 no.2
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• pp.223-234
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• 2016

Two-component epoxy resin is widely used in the cultural heritage restoration field. However according to mixing ratio of resin and hardener, curing property, mechanical strength and chemical structure differ which have possibility to effect the stability of cultural heritage. Result of questionnaire survey shows hands-on workers in the conservation field tend to mix the epoxy resin with his or her eye measurement when the using amount is small or mix additional hardener to shorten the pot life of epoxy resin. This research aims to analyze the curing property, mechanical strength and chemical structure of rapid curing type epoxy resin and medium curing type one depending on relative ratio of 0.25~4 of hardener to resin. When the amount of hardener was 0.5~2 times more than the resin, exothermic heat and curing speed were both increased. In case of included hardener to resin was lower than official ratio, mechanical strength (tensile shear strength, tensile strength and compressive strength) became higher along with active cross-linking bonding of the epoxy resin. Medium curing type epoxy relatively had lower exothermic heat and slower reaction during curing process. It was observed to be put to definite point of mechanical strength under lower content of hardener than official ratio. While, hardener ratio more than twice the resin slowed down the curing greatly and lowered the adhesion strength also. In conclusion, under the lower mixing rate of hardener than official ratio would show relatively fast reaction with similar mechanical strength. Over the official ratio on the other hand, material property drops rapidly. Accordingly, mixing ratio of epoxy resin is expected to be influential to the stability of cultural heritage.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.2
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• pp.90-96
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• 1997

Until now the research was usually related in the fishing basket for crab charybdis japonica, concentrated one's effort to modification on the construction, shape, number of entrance of fishing basket etc.. But there's not make good used to the basically habit, shelter behavior of crab. etc., and was not fundamentally modified to the ability attracting the crab on net fishing basket. In this paper, first of all investigated to the behavior of crab in water tank and then two types modification fishing baskets could the increasing to ability attracting of crab on fishing basket were designed from the result obtained in this experiment and compared with modificated net fishing basket by Kim.Go(1987.1990) at a field and tank experiment. The results obtained are summarized as follows : 1. Being the fishing baskets had dropped in the tank bottom, the touched rate and reacted rate of crab according the elapsed time agree with to experiment of Kim.Go(1987.1990)in the mainly. however, in case of plate type tangle net, the touched rate of crab increased for a short time and then decreased and the reacted rate increased in a hurry to show a maximum and then was established. 2. The beginning catch time of crab was shortest in the plate type tangle net than the any fishing baskets because it's immediately entangled if the crab was touched only a part of body on net and latest in the net fishing basket. 3. A distance of between the touched rate and the reacted rate curve were the most short, wide in the plate type tangle net. therefore, the ability attracting of crab was excellent than the any fishing baskets and in case of pipe type fishing baskets, between the 150mm and 250mm seemed not difference and showed a tendency to increasing against the net fishing baskets. 4. Pipe type fishing baskets seemed to become a good shelting place for the crab because it showed a tendency to stagnate at the inside in that. 5. The mean catch per pot of crab among the net fishing basket, pipe type fishing baskets, plate type tangle net were highest in the pipe type fishing baskets than the net fishing basket and lowest plate type tangle net. Therefore it showed to difference against the tank experiment.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.3
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• pp.133-140
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• 2010

Carbon fiber has many potential applications in a wide array of fields of solar cell, fuel cell, batteries, and polymer matrix composites due to an exceptional mechanical properties and chemical stability. In this study, the effects of catalysts on the property of carbon nanostructures grown on the carbon fiber were systematically investigated. The surface treatment of carbon fiber and catalysts synthesis for carbon nanostructures growth were carried out by one-pot ELP method and thermal CVD, respectively. The surface morphology and crystal structure of carbon nanostructures were examined using a field emission scanning electron microscope and transmission electron microscope. Depending on the type of catalysts and the molar ratio, various types of carbon nanostructures like carbon nanotube, carbon nanofilament, carbon nanospring and etc. were synthesized on the surface of carbon fibers surface.

• Journal of Technologic Dentistry
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• v.35 no.1
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• pp.57-64
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• 2013

Purpose: Waste parts of zirconia blocks and powders were remained after CAD/CAM process. In order to make these residual zirconia fit for practical use, zirconia single cores were produced by drain casting process. Methods: Remained zirconia blocks were reduced to powders with zirconia mortar, and screened with 180 mesh sieve. Zirconia slip was prepared from waste parts of zirconia by ball milling. Plaster molds for forming cores by slip casting were also prepared. Formed cores were removed from mold after partial drying. Dried cores were biscuit fired at $1,100^{\circ}C$ for 1hour. Biscuit fired cores were treated with tools to control the fitness and thickness. Finished cores were $2^{nd}$ fired at $1,500^{\circ}C$ for 1hour. Microstructure of cross section of core was observed by SEM. Results: When mill pot was filled with 100g of zirconia and alumina mixed powder, 300g of zirconia ball, and 180g of distilled water, the optimum slip for drain casting was obtained. Gypsum plaster for ceramic forming was more suitable then yellow stone plaster for casting process. SEM photograph showed the microstructure of fully dense with uniform grain size of zirconia and well dispersed alumina grains into the zirconia matrix. Conclusion: Zirconia single cores were produced by drain casting process. Drain casting is useful process to make these residual zirconia fit for practical use. Further study will be focused on the preparation of the bridge type cores by casting.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.296-301
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• 1999

The concerns on the crop damage by ultraviolet (UV) radiations is increasing owing to the decrease of their absorbing stratospheric ozone in the tropospheric. Cultivar differences on early growth of UV radiation among five Korean rice cultivars, four japonica types and one Tongil type (indica-japonica cross hybrid), were studied. Pot-seeded rice plants were grown under four different radiation conditions, i.e., visible radiation only, visible radiation with supplemented with high or low dose of UV-B (280~320 nm in wavelength) and UV-C (less than 280 nm in wavelength). The inhibitory degree on plant height, shoot and root weight and length of leaf blade and leaf sheath were determined at 40 days after seeding. UV-C showed the most severe inhibitory effect on the degree of biomass gain and leaf growth in most cultivars examined, followed by high UV-B and low UV-B. Among the cultivars used, the Kuemobyeo was the most sensitive cultivar and had not repair or showed resistance ability to continued irradiation of UV radiation. However, Janganbyeo and Jaekeon showed different responses that the elongation of leaf blades was promoted on 2nd and 3rd leaves and inhibited on 4th and 5th leaves but this inhibitory degree was reduced on 6 th and 7th leaves. Such tendency on leaf growth means that both cultivars had low sensitivity and most resistant ability to continued irradiation of UV radiation. While Tongil showed different response to enhanced UV radiation, ie., low UV-B promoted leaf growth but the inhibitory was severely increased by continued irradiation of high UV-B and UV-C, which means that Tongil had high threshold of UV radiation for response as an inhibitory light of plant growth. The results of this study indicate that the differences on sensitivity or resistant to the effects of UV radiation were existed among Korean rice cultivars.

• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1500-1512
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• 2017

In this study, the siderophore-producing characteristics and conditions of Bacillus sp. PZ-1 were investigated and the enhancement of siderophores on Pb uptake and translocation in Brassica juncea were determined. Results of single factor experiment showed that glucose, pH, and $Pb(NO_3)_2$ could stimulate PZ-1 growth and siderophore production. The maximum siderophore production of 90.52% siderophore units was obtained by response surface methodology optimization at the glucose concentration of 21.84 g/l, pH 6.18, and $Pb(NO_3)_2$ concentration of $245.04{\mu}mol/l$. The type of siderophore was hydroxamate and its concentration in the fermentation broth amounted to $32.24{\mu}g/ml$. Results of pot experiments indicated that the siderophores enhanced B. juncea to assimilate more Pb from soil with the uptake ratio from 1.04 to 2.74, and to translocate more Pb from underground to overground with the TF values from 1.21 to 1.48. The results revealed that Bacillus sp. PZ-1 could produce abundant siderophores and might be potentially used to augment the phytoextraction of Pb from soil.

• Journal of Plant Biotechnology
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• v.30 no.2
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• pp.179-184
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• 2003

In order to establish micropropagation system Anthurium andreanum 'Atlanta', dwarf type, shoots of A. andreanum were cultured on medium supplemented with cytokinin. Callus was formed from the base of shoots. high frequency callus induction was obtained on medium with 10.0mg/L BA or 10.0mg/L TDZ(thidiazuron) at more than 71.8%. The shoots were cultured on media with various combinations and concentrations of TDZ, BA and 2.4-D to enhance callus induction. Callus was induced at more than 72.6% and grew vigorously on media containing 10.0mg/L BA and 0.0∼0.5mg/L 2.4-D, or 1.0mg/L TDZ. Stimulation effects of cytokinin by 2.4-D did not occur in combined treatments of cytokinin and 2.4-D. Callus was cut into sections(7${\times}$10mm), and then cultured on media with BA alone or BA and 2.4-D to regenerate shoots and to stimulate the callus growth. Shoot regeneration and callus growth were effective on media with 10.0mg/L BA alone, or 10.0mg/L BA and 0.1mg/L 2.4-D. In combined treatments of BA and 2.4-D, stmulation effects of cytocinin by 2.4-D also did not occur. Callus growth was decreased, accordiong to increasing the concentration of 2.4-D. In cimbined treatments of TDZ and 2.4-D in shoot regeneration and callus proliferation, stimulated effects of cytokinin by 2.4-D did not occur entirely. Media with 0.5∼1.0mg/L TDZ ingibited the regeneration and rooting of shoots, and callus growth from callus sections. Addition of 2.4-D on medium with TDZ ingibited the regeneration and rooting of shoots, and callus growth. Rooted plantdts were acclimatized in greenhouse. The plantlets were survived more than 98% in soil of vermiculite alone or mixed perlite 1 and vermiculite 1.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.1
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• pp.77-84
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• 2004

This study was conducted to suggest vegetation mat forming methods with native wildflowers, introduced wild flower, grasses and native herb plants which can be used for erosion control of the disturbed slopes. The main results are summarized as follows. In forming the vegetation mat at early stage, foreign grasses, native wild plants shows more effective than the other seed mixture types. But, after 12 weeks, using native wild flowers shows more effective than foreign grasses. Also, the mixture of the native grasses and kentucky bluegrasses (seed mixture type F) are the best in ground coverage among the seed mixtures types. In order to restore slopes more naturally, more diverse plants should be used. The native grasses such as Marrubium incisum Bentham, Lutos comiculatus L. var. japonicus Regel, and Artemisia princeps Pampan seems to be useful to forming the vegetation mat, also it will be more easy if mixing with foreign grasses such as Kentucky bluegrass. The mixture of native grasses and introduced wild flowers are not proper in forming the vegetation mat. Also, pot planting of the native grasses are not proper in forming the vegetation mat.

• Journal of Life Science
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• v.11 no.3
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• pp.235-241
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• 2001

To select the sntagonistic bacteria against B. cinerea, isolates were screened from the eggplant leaves and rhizosphere soils in the eggplnat fields in the greenhouse. W1 and P99 isolates were selected by the inhibition of mycelial growth of B. cinerea E12 in vitro test. These isolates, W1 and P99, were identified as Bacillus subtilis and Pseudomonas putida, respectively, by the Bergeys manual and API systems, For the formulation of the antagonistic bacteria, the media for the mass production were prepared with biji(soybean curd residues) or soybean flour. B. subtilis W1 or P. putida P99 was mass cultured in biji broth or soybean flour extrect broth and then soybean flour, corn starch flour, rice glutinous flour and biji flour as high molecular substrates were added. These mixtures were dried, grinded and formulated as brofungicides of wettable powder type. The assess the control effect of biofungicides against the infection of B. cinerea, six types of formulations were assayed at the pot culturing with eggplant in the greenhouse. According to the results, there were no significant differences among the formulation methods. However, P99S or PppB formulated with P. putida P99 showed the highest control values as 90.4% and 96.1%, respectively. Then. BSB or BSD formulated whit B. subtilis W1 were 80.8% and 83.0%, respectively. There afforementioned values were more effective than that of chemical fungicide. Ipro W.P which showed as 72.6%.

• Journal of Technologic Dentistry
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• v.40 no.1
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• pp.17-25
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• 2018

Purpose: When casting of ceramics, proper amount of deflocculant was added for disperse the particles in slip. In this study, examined the optimum amount of APMA(ammonium polymethaacrylate) water as deflocculant for casting the zirconia. Methods: The 100 g of zirconia powder were ball milled with 300 g zirconia ball, 90 g of distilled water, and APMA water in polyethylene pot for 24 hours. The amount of APMA water were added as deflocculant from 0.5 to 0.9 g at an intervals of 0.1 g. The viscosity of slip with no deflocculant showed 1362c.p. and the minimum viscosity with 580c.p. obtained when the slip contained 0.7% of deflocculant. Bar type specimens were casted with plaster mold and biscuit fired at $1100^{\circ}C$ for 1 hours. Biscuit fired specimens were finished with $60mm(L){\times}14mm(W){\times}10mm(H) bar$. Finished specimens were 2nd fired at $1500^{\circ}C$ for 1 hour. Results: Regardless the addition of deflocculant, all 2nd fired specimens showed 0% of apparent porosity and water absorption. The specimens with no deflocculant showed 24% of drying shrinkage and 27.4% firing shrinkage. On the other hand, The specimens with deflocculant showed 17.4% of drying shrinkage and 17.6% firing shrinkage regardless the amount of deflocculant. The maximum bulk density with $6.09g/cm^3$ obtained when the specimens casted with 0.7~0.9% of deflocculant contained slips. Bend strength of specimen with no deflocculant showed 680 MPa and the maximum bend strength with 814 MPa obtained when the specimen casted with 0.7% of diflocculant contained slip. Conclusion : It was found that the particle shape of the powder according to the dispersing agent is added, the particle size, sintering temperature and affect the particle size distribution, sintering time, sintering atmosphere, such a great influence on the sintering.