• The Mathematical Education
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• v.39 no.1
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• pp.37-47
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• 2000

Number concept is basic in mathematics education. But it is very complex and is not easy to understand real number concept, because of its infinity. This study tried to show that what percents of secondary school mathematics teachers in Korea understood the properties of real number, such as cardinality, continuity, relation with real line, and infinity, which were written by verbal language.

• Journal of Korean Society of Forest Science
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• v.85 no.1
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• pp.1-14
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• 1996

The object of this study was to examine the effects of air pollution on forest vegetation structure in the vinicity of Sasang industrial complex in Korea. Forest vegetation structure was investigated at 19 sample plots surrounding industrial complex and at one site away from industrial complex as a control. The results obtained were as follows; 1. For analysis of vegetation structure, upperstory of forests was mostly consisted of Pinus thunbergii, and partly of Alnus firma and Robinia pseudoacacia. In midstory, major components were Pinus thunbergii, Robinia pseudoacacia, Rhus trichocarpa, Rhus chinensis and Styrax japonica, In lower story, Pinus thunbergii was a minor component, while Robinia pseudoacacia, Quercus serrata, Rhus trichocarpa. and Rhododendron yedoense var. poukhanense which were known to be resistant to air pollution were found in large number. Especially, importance percentage of Robinia pseudoacacia was high, while that of Rhododendron mucronulatum was low in surrounding industrial complex. 2. For woody plants, number of species, species diversity and similarity index in industrial complex, were not significantly different from those in control plot. 3. For herbs, Oplismenus undulatifolius appeared in large number in most plots. The $SDR_3$ of Miscanthus sinensis, Calamagrostis arundinacea, Paederia scandens, Spodiopogon cotulifer and Carex humilis were high, but that of Aster scaber, Saussurea seoulensis, Solidago virgaaurea var. asiatica and Prunella vulgaris var. lilacina were low in the vicinity of industrial complex. 4. Number of herb species decreased to below 10 species at surrounding industrial complex as compared to 20 species in the control plot. In addition species diversity, and similarity index in the industrial complex were lower than those in control plot. It may be concluded that Pinus thunbergii forests in industrial complex consists of tree species resistant to air pollution, and that composition of woody vegetation in industrial complex was not much different from control plot, while composition of herbs was already quite different between the two plots. Forest vegetation structure, therefore, may change with time due to air pollution in the industrial complex.

• Journal of the Korean Applied Science and Technology
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• v.14 no.1
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• pp.89-93
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• 1997

In this research, ultra-thin films of organic charge transfer complex were deposited on to ordinary microscope slide-glass subtrates with a Langmuir-Blodgett technique. ${\pi}$-A isotherm characteristics of these complex were studied in order to find optimum conditions of deposition by varying temperature of subphase, compression speed, and spreading amount. Transfer ratio of these films were studied during the process of deposition. The UV-visible absorbance spectra of LB films were measured to find state of deposition by varing layer number. The observed optimum conditions of surface, pressure, spreading amount, and dipping speed for depositing LB films(Y-type) were 38m/Nm, $150{\mu}l$ and 5mm/min, respectively. Since the tansfer ratio is close to 100%, the monolayer on the subphase seems to be well transferred to the solid substrate. The thickness of the film was well-controlled as the UV-vis absorbance of films were changed linear according to the number of layers.

• Korean Journal of Plant Taxonomy
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• v.47 no.4
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• pp.304-307
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• 2017

We report somatic chromosome numbers for three species belonging to the Euphorbia pekinensis complex distributed in Far East Asia. In E. pekinensis populations distributed in Korea, 2n = 28 and 56 were found, while the Japanese native E. lasiocaula was also found at 2n = 28 and 56 and the Japanese endemic E. sinanensis was found at 2n = 20. Based on the number of chromosomes, E. lasiocaula distributed in Japan supports treatment as a variety of E. pekinensis rather than as a different species, while E. sinanensis should be recognized as a distinct species rather than as a variety of E. pekinensis. In the same populations of E. pekinensis and E. lasiocaula, diploid and tetraploid individuals were found, and the diversity of these chromosome numbers was consistent with the morphological diversity of these populations, suggesting the future evolutionary potential of this species.

• The Pure and Applied Mathematics
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• v.23 no.2
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• pp.155-162
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• 2016

In this paper, we solve the additive ρ-functional inequalities (0.1)${\parallel}f(x+y)+f(x-y)-2f(x){\parallel}$ $\leq$ ${\parallel}{\rho}(2f(\frac{x+y}{2})+f(x-y)-2f(x)){\parallel}$, where ρ is a fixed complex number with |ρ| < 1, and (0.2) ${\parallel}2f(\frac{x+y}{2})+f(x-y)-2f(x)){\parallel}$ $\leq$ ${\parallel}{\rho}f(x+y)+f(x-y)-2f(x){\parallel}$, where ρ is a fixed complex number with |ρ| < 1. Furthermore, we prove the Hyers-Ulam stability of the additive ρ-functional inequalities (0.1) and (0.2) in complex Banach spaces.

• The Pure and Applied Mathematics
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• v.23 no.2
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• pp.145-153
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• 2016

In this paper, we solve the quadratic ρ-functional inequalities (0.1) ${\parallel}f(x+y)+f(x-y)-2f(x)-2f(y){\parallel}$ $\leq$ ${\parallel}{\rho}(4f(\frac{x+y}{2})+f(x-y)-2f(x)-2f(y)){\parallel}$, where $\rho$ is a fixed complex number with $\left|{\rho}\right|$ < 1, and (0.2) ${\parallel}4f(\frac{x+y}{2})+f(x-y)-2f(x)-2f(y){\parallel}$ $\leq$ ${\parallel}{\rho}(f(x+y)+f(x-y)-2f(x)-2f(y)){\parallel}$, where ρ is a fixed complex number with |ρ| < $\frac{1}{2}$. Furthermore, we prove the Hyers-Ulam stability of the quadratic ρ-functional inequalities (0.1) and (0.2) in complex Banach spaces.

• Korean Journal of Poultry Science
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• v.30 no.3
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• pp.145-150
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• 2003

A feeding trial was carried out to investigate the effect of dietary complex probiotics on performance. egg qualities and intestinal microflora in laying hens. Three hundred twenty ISA Brown laying hens, 34 weeks of age, were randomly allotted to four dietary treatments containing 0, 0.1, 0.2 and 0.4% complex probiotics for 12 weeks. There were four replicates per treament. Total egg production, soft and broken egg number tended to improve as dietary complex probiotics increased, but was not significantly different. Average egg weight was significantly higher in the 0.1% and 0.2% complex probiotics than the control(P<0.05). Daily egg mass also increased by adding complex probiotics compared to that of control, but was not statistically different. No significant difference was found in feed intake and feed conversion ratio. Eggshell breaking strength and thicknes were not significantly different, whereas yolk color was significantly lower in the supplemental 0.2% probiotics than the comtrol at 12 weeks of age(P<0.05). There was no significant difference in Haugh unit. Total number of cecum Lactobacillus and naerobes were significantly higher in the complex probiotics than control(p.0.05). However, the number of ileal Lactobacillus and naerobe were not significantly different. It was concluded that dietary complex probiotics could improve the egg weight and intestinal beneficial microbes.

• Korean journal of applied entomology
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• v.33 no.4
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• pp.216-224
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• 1994

Sex combs which lack in females are characteristic of some members of the subgenus Sophophora When present, they can be van/ from a single blistle to very extensive structures, but the meianogaster subgroup of the subgenus Sophophora have only on the f~rst tarsal segments of the fore legs. D mauritiona among the melanogaster compler of the melar~ogaster subgroup have significantly more sex comb teeth (mean 12.75) than other specie& and the yakubo complex (range of the mean 6.84-758) have less than the melanogaster complex (range of the mean 835-12.75). In sex comb tooth number of interspecd~ch ybrids among the melonogoster complex, there appeared difference u;ith parental species Thus, analysis of male sex comb tooth in FI hybrid could not exhibit the direction of hereditan/ nature. On the other hand, D auraria (the montium subgroup), D suzuki (the suzuki subgroup) and D, lutecens (the takohashii subgroup) of the melanogaster species have two sex combs on the first and second tarsal segments, and the mean number were different according to the species.

• Korean journal of applied entomology
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• v.34 no.4
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• pp.308-313
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• 1995

Drosophila melanogaster, D. simulans, and D. sechellia are closely related species which belong to the D. melanogaster complex; the first two cosmopolita and the last one restricted to th Seychelles archipelago. The phenogenetical relationship between this complex and their hybrids were investigated by the comparison of sex-comb tooth number an genital arch of male. In interspecific hybrids of all crosses between three species four hybrid males were produced and completely sterile. Males of D. simulans (${O}_{9}$) have significantly less sex-comb teeth (mean 8.35) than either D. melanogaster (OR, mean 10.73) and D. sechellia (Ja, mean 10.60). From the analysis by the number of sex-comb tooth in interspecific hybrids we could not represent the direction of heredity nature. each species of D. melanogaster complex were characteristic in the shape of the genital arch, which readily allows these species to be distinguished. The common structure of the genital arch in the interspecific hybrids were mosaic-like structure between parental species.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.06b
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• pp.185-194
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• 1999

This paper suggests the new techmology to control metal flow in order to reduce the number of preforming and machining for the cold forged product with complex geometry. This technology can be summarized the complex forming, which consists of bulk forming and sheet forming, and multi-action forging, which be preformed double action dies. To analyze the process, finite element simulation has been performed. The proposed technology is applied to hub which is part of air conditioner clutch. According to the result of this study, the relative velocity of mandrel and punch is primary process variable.