• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.129-138
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• 2012

The aim of this in vitro study was to evaluate the effectiveness of experimental 2.26% fluoride-polyvinyl alcohol (F-PVA) tape in inhibition of enamel demineralization using enamel surface microhardness (SMH) analysis and scanning electron microscopy (SEM) examination. Enamel specimens (n=60) randomly assigned to four groups: control group, F-PVA tape group, fluoride varinish (F-varnish) group, casein phosphopeptide-amorphous calcium phosphate (CPP-ACFP) group. After topical application, pH-cycling was processed. Then, SMH was measured and the percentage loss of surface microhardness (%SML) was calculated. For the SEM examination, five sample specimens in each group were treated and the morphologic character was evaluated. After pH-cycling, the SMH values of the enamel specimens of F-PVA tape and F-varnish group were significantly higher than that of CPP-ACFP group, there was no significant difference between F-PVA tape and Fvarnish group. With SEM examination, enamel surfaces in the F-PVA tape group and F-varnish group showed numerous spherical and ovoid crystals formed on the enamel surface were also observed. The density of crystals was higher than that of both control group and CPP-ACFP group. F-PVA tape is effective in inhibition of enamel demineralization. Also, F-PVA tape's inhibition of enamel demineralization is comparable to that of F-vanish and greater than that of CPP-ACFP.

• Korean journal of applied entomology
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• v.21 no.2 s.51
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• pp.87-94
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• 1982

The mymarids egg parasite of rice planthopper, Anagrus nr. flaveolus, were investigated to know their parasitic activities after overwitering in the paddy banks and barley fields, their host preferences and seasonal variations in the pesticide sprayed and unsprayed paddy fields of Gyeongnam province O.R.D. at Jinju from 1977 to 1979. The parasitic activities of Anagrus nr. flaveolus after overwintering in the paddy banks were high early in April and tended to decrease remarkably since mid-April by moving to the barley fields. The parasitic rate of Anagrus nr. flavelous was $47.2\~88\%$ between middle and late in April, the peak of egg deposition period. Anagrus nr. flaveolus parasitized Laodelphax striatellus, Nilaparvata lugens, and Sogatella furcifera, but didn't attack the eggs of Nephotettix cincticeps in the paddy fields. High preference was observed with Laodelphax steriatellus. The parasitic activities of Anagrus nr. flaveolus in the pesticide sprayed paddy fields were high in early July and from late August to early September. The parasitic rate in the pesticide unsprayed fields were higher than those of sprayed fields during the pesticide spraying period, from July to August and parasitic activities were active from October to before coming winter.

• Journal of the Korean Institute of Gas
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• v.20 no.4
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• pp.7-14
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• 2016

The economic crisis in North Korea has reduced its capacity to invest in the energy industries. The country is going through a vicious cycle of decreased investment in the energy industries and reduced energy production. This suggests that the energy industries would come to the top priority of investment once the economy improves. This paper calculated the economic ripple effect of the investment on North and South Korean economies based on the assumption that 390 billion won was invested in the construction of a natural gas combined-cycle power plant in Gaesong Industrial Complex. In order to analyze the economic ripple effect of the investment on North Korean economy, we constructed the inter-industry relation table of North Korea for year 2014 and used the input-output model. The ripple effect of the investment in the natural gas industry turned out to be 1.012 billion dollars. In order to analyze the effect of the investment on South Korean economy, we constructed the inter-industry relation table of South Korea for year 2013 and used the demand-driven model for inter-industry analysis. As a result, production, added-value and employment inducement coefficients of the investment in the natural gas industry were calculated as 2.02073, 0.62697 and 8.99409 respectively.

• The Transactions of the Korea Information Processing Society
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• v.4 no.2
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• pp.465-482
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• 1997

In this paper, we have studied on cinstructing code-recognition shstem by neural network according to a image process taking the DOT classification code stamped on tire surface.It happened to a few problems that characters distorted in edge by diffused reflection and two adjacent characters take the same label,even very sen- sitive to illumination ofr recognition the stamped them on tire.Thus,this paper would propose the algorithm for tire code under being cinscious of these properties and prove the algorithm drrciency with a simulation.Also,we have suggerted the MCBP network composing of multi-linked recognizers of dffcient identify the DOT code being tire classification code.The MCBP network extracts the projection balue for classifying each character's rdgion after taking out the prjection of each chracter's region on X,Y axis,processes each chracters by taking 7$\times$8 normalization.We have improved error rate 3% through the MCBP network and post-process comparing the DOT code Database. This approach has a accomplished that learming time get's improvenent at 60% and recognition rate has become to 95% from 90% than BckPropagation with including post- processing it has attained greate rates of entire of tire recoggnition at 98%.

• KSBB Journal
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• v.9 no.3
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• pp.246-252
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• 1994

Enzyme-catalyzed polycondensatlon reaction of aliphatic polyesters with several repeating units was studied using the biocatalytic activities of lipases from different sources. Porcine pancreatic lipase (PPL) was found to be best in utilizing bls(2,2,2-trichloroethyl) glutarate and 1,4-butanediol as substrafes. The reaction was also catalyzed to some extent by the lipases from Humicola lanuginos and Psudomonas sp. In the series of short-chain diols(C2-C4), bis(2,2,2-trichloroethyl) glutarate was iransesterified fastest with 1,4-butanediol and for the long-chain diols (PEG-300-PEG-1000), the reaction was fastest with PEG-400. With PEGs, only monoesterification product was obtained. PPL functioned well in relatively hydrophilic organic solvents such as tetrahydrofuran(THF), ether and acetonitrile. The reaction rate was accelerated as the reaction temperature was raised from $20^{\circ}C$ to $60^{\circ}C$ while Mn values of the reaction products were not affected by the reaction temperature. End group analysis by NMR showed that Mn values of the polymer were in the range of 1500-4000 daltons.

• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.290-303
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• 2011

The purpose of this study was to introduce the practical model on the enhancement of the divergent and convergent thinking skills through inquiry instruction in science class. In this study, the creative thinking skill has been defined by divergent thinking skill as the narrow sense. In the science field, the problem solving thinking skill is just same as the inquiry thinking skill. Also, the problem solving thinking skill has been defined by convergent thinking skill as the critical thinking skill. This new instruction had been used for the college student in the class of general chemistry laboratory for the one semester. The first results had been founded that the students' divergent thinking skill had been increased significantly. Especially, the skills of recognition of problems, the skills of making hypothesis, and the skills of transformation and interpretation of data had been increased significantly. The second results had been founded that the students' convergent thinking skill had been increased significantly. Especially, the skills of making hypothesis, the skills of transformation and interpretation of data, and the skills of making conclusion and generalization had been increased significantly. The third results had been founded that the students' the creative and problem solving thinking skill had been increased significantly. Especially, the rest of all skills exception the skill of control variables had been increased significantly.

• Korean Journal of Environment and Ecology
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• v.21 no.3
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• pp.257-277
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• 2007

We carried out a phytosociological study on pine forests in Korea with the method of Zurich-Montpellier School. We collected the data of 252 $relev{\acute{e}}s$ from 45 sites in the pine forests throughout the Korean Peninsula and its attached islands. The vegetation of the pine forests was classified into one association, three communities and seven subcommunities as follows: A: Quercus mongolica-Pinus densiflora community, A-1: Typical subcommunity, A-2: Vaccinium korean urn subcommunity, A-3 : Rhododendron micranthum subcommunity, B: Quercus serrata-Pinus densiflora community, B-1: Typical subcommunity, B-2: Juniperus rigida subcommunity, B-3: Styrax japonica subcommunity, B-4: Eurya japonica subcommunity, C: Saso-Pinetum densiflorae Yim et al. 1990, and D: Castanopsis cuspidata var. sieboldii-Pinus densiflora community. The former three communities were integrated into the Lindero-Quercion mongolicae Kim 1990 em. 1992. The Castanopsis cuspidata var. sieboldii-Pinus densiflora community remained to be studied in future to determine the association. The communities of Quercus mongolica-Pinus densiflora community was distributed throughout the montane zone in central-northern part of the Korean Peninsula. Quercus serrata-Pinus densiflora community occupied widely in the sub-montane and hilly areas in central and Southern Korean Peninsula. The association of Saso-Pinetum densiflorae was found in Cheju Island. Castanopsis cuspidata var. sieboldii-Pinus densiflora community were distributed in the warm-temperate zone including islands off the south-west coast of the Peninsula.

• Korean journal of applied entomology
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• v.22 no.4 s.57
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• pp.233-236
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• 1983

Results obtained from the experiment conducted to determine the potential distribution of greenhouse white flies are summerized as follows; Hatching rate of eggs were significantly decreased when eggs were treated under $-5^{\circ}C$ for three days and no eggs were hatched when 4he eggs were treated at $10^{\circ}C$. for three days. Kate of pupation was also decreased when larvae were subjected to $-5^{\circ}C$ for three days and no pupation of larvae was of served when the larvae were under $-20^{\circ}C$ for three days. Emergency rate of pupae was decreased when pupae were under $-20^{\circ}C$. for three days and no emergence was observed when pupae were treated at the temperature of $-20^{\circ}C$ for three days. Survival rate of adults were greatly decreased when they were under $-7.5^{\circ}C$. for three days and the adults were completely dead when they were subjected to $-10^{\circ}C$. for three days. Therefore, it may be concluded that the greenhouse white flies may be overwintered, in the from of pupae at the middle-southern part of Korea, while they may overwinter in all developmental stages in Jeju Island and in southern tip coast area of Korea.

• Korean journal of applied entomology
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• v.21 no.3 s.52
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• pp.138-141
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• 1982

The insecticides aldicarb$(Temik^{(R)}\;15G)$, carbofuran$(Curaterr^{(R)}\;3G)$, and disulfoton$(Disyston^{(R)}\;5G)$ were evaluated in the field for the control of the pine gall midges(Thecodiplosis joponensis Uchida et Inouye) at rate of 5 a.i.g/cm dbh using the method of circle-furrow treatment(ca. loom in furrow depth), apart 50cm Iron the trunk of the pine trees. In addition, for improving the application method of granular insecticides the effects of conventional circle-furrow treatment were compared with those of pit treatments and radical-furrow treatments. A single root-zone treatment of aldicarb and carbofuran i the pine trees was significanlty effective for the pressure of the gall incidence by the insects. Control effectiveness in three-pit treatment was identical with those in conventional circle-furrow treatment. The pit treatment compared with the circle-furrow and radical furrow treatments would be a further feasible method in saving labor cost.

• Korean journal of applied entomology
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• v.27 no.2
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• pp.87-93
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• 1988

Some attempts were made to investigate the biological characteristics of the brown planthopper(BPH), Nilaparvata lugens St${\aa}$l, biotypes in terms of perference in feeding oviposition on rice field, egg and nymphal periods, egg hatchability, emergemce ratio, growth index, adult lingevity and gecundity fed on 60-day-old rece cultivaes with different resistance genes. Feeding and oviposition perference of the three BPH biotypes on Dongjinbyeo with no resistance gene were shown very higher than on rice cultivars with resistance genes. Those of biotype-2 on Cheongcheongbyeo with bph 1 gene and bitype-3 on Milyang 63 with bph 2 gene were relatively high, however, they were still remarkably lower than those of Dongjibyeo. The egg and nymphal periods of the three BPH biotyes on Milyang 23 were shorter than on the other rice cultivars. The periods of biotype-2 on Cheongcheongbyeo and biotype-3 on Milyang 63 were as short as those of the three BPH biotypes on Milyang 23. The egg hachability, emergence ratio, and growth index of the three BPH bioyoes on Milyang 23 were higher than on the other rice cultivars and those of biotype-2 on Cheongcheongbyeo and biotyoe-3 on Milyang 63 were as high as on Milyang 23. The female adult longevity of the BPH biotype-1 on Milyang 23 was longer than on the other cultivaes, and that of biotype-2 on Cheongcheongbyeo and bioty-3 an Milyang 63 were as ling as on Milyang 23. The number of egg laid by a female of the three BPH biotypes were greatly increased on Milyang 23. Those of biotype-2 on Cheongcheongbyeo and biotype-3 an Milyang 63 were also greatly increased.