• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.308-312
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• 2019

Amphiphilic gold nanoparticles were synthesized by the functionalization of gold nanoparticles with hydrophilic and hydrophobic ligands on their surfaces, which can be applied to many disciplines such as biology, photonics, electronics, and so on. The ratio of hydrophilic and hydrophobic ligands plays an important role in such applications since the ratio is closely related to physiochemical properties of the nanoparticles. In this paper, the effect of temperature during the ligand exchange reaction on the ratio of ligands on the gold nanoparticle surface was investigated. Hydrophilic ligands have higher affinity to the nanoparticle surface with an increase of the temperature. Furthermore, the amphiphilic nanoparticles at a higher temperature were more soluble in an aqueous solution even with a lower hydrophilicity of the nanoparticle surface.

• Journal of Korean Society of Forest Science
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• v.75 no.1
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• pp.51-54
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• 1986

The good growth of Populus alba ${\times}$ P. glandulosa is shown at the foothill of the mountain where good soil moisture is available, but its growth is poor at the upper part of the mountain where soil moisture is limitted. Stomatal frequency, stomatal size and transpiration rates that affect soil moisture demand were determined in order to know how this character is inherited from its parents. Number of stomata per $mm^2$, length and width of stomata from the abaxial leaf and transpiration rate ($g/cm^2$) per day in P. alba ${\times}$ P. glandulosa showed intermediate values between those of their parents, while P. alba showed the highest values and P. davidiana the lowest values. The values of stomatal frequency of P. alba ${\times}$ P. glandulosa were close to the expected mean values of parents in the $x^2$ test, and in the regression analysis the transpiration rates for the hybrid and its midparent had strong relationship with 0.97 of regression coefficient. The fact that these intermediate characteristics were observed in the hybrid suggests incomplete dominance in the hybrid. It is concluded that soil moisture demand in P. alba ${\times}$ P. glandulosa and its parents is closed related to stomatal frequency, stomatal size and transpiration rate.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.262-269
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• 1994

This study was conducted to clarify high yielding factors of F$_1$ hybrids in terms of the growth characteristics, canopy structure, nitrogen content and nitrogen profile in the canopy. Varieties used in this study were four hybrid rices showing different heterosis in grain yield and their parents. Varieties of Japonica were Reimei (maintainer), TP 681 and TP 1278(restorers), and F$_1$ (Reimei ms ${\times}$ TP 681, Reimei ms ${\times}$ TP 1278) hybrid rices. Those of Indica type were 1378 (maintainer), Milyang 46 and Suweon 287(restorers), and F$_1$ (1378 ms ${\times}$ Milyang 46, 1378 ms ${\times}$ Suweon 287) hybrid rices. High heterosis in F$_1$ hybrid rices were shown in panicles per hill and spikelets per panicle, being greatest in spikelets per panicle. Spikelets per square meter expressed even greater heterosis than those two yield components because of multiplicative effect of them. Heterosisof ripened concentration of leaf nitrogen and steeper gradient of leaf nitrogen in canopy strata but also better productive structure in favor of light interception seemed to have led to higher canopy photosynthesis of F$_1$ hybrids and subsequent higher partition of assimilates for leaf area expantion especially during vegetative growth stage. Higher dry matter production, resulting from these factors, during vegetative stage would have contributed to the production of greater number of spikelets per square meter, and consequently to higher grain yield in F$_1$ hybrids.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.412-419
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• 1994

This study was carried out to investigate changes of chemical composition in seed, germination percentage, and seedling growth of two F$_1$ hybrid rices(V20A/Cheongcheongbyeo, IR62829A/Cheongcheongbyeo) during germination compared with their parents (V20B, IR62829B and Cheongcheongbyeo) and check variety(Samgangbyeo). F$_1$ hybrid rice showed higher content of free amino acid, inorganic elements, ($P_2O_5$, $K_2$O, MgO) and total sugar, and higher a-amylase activity in brown rice than those of their parents and check variety during germination. Therefore$F_1$hybrid rices showed hybrid vigor in germination percentage at 33 hour and 48 hour after sowing. $F_1$ Hybrid rices also showed /heterosis in seedling growth was different between V20A/Cheongcheongbyeo and IR 62829A/Cheongcheongbyeo. There were positive significant correlation between a-amylase activity and germination percentage, and seedling growth.

• Korean Journal of Plant Tissue Culture
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• v.25 no.3
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• pp.165-169
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• 1998

Anthers of three cross combinations of hot-pepper(Capsicum annuum L.) were cultured on Dumas De Vaulx medium supplemented with some growth regulators. The embryo production efficiency and the diversity for agronomic traits in $A_2$ lines were investigated. The embryo production frequencies of hybrid combinations were ranged from 16.4% to 43.4%, the highest embryo induction combination was DGSH $\times$ C-NH with 43.4% embryogenic efficiency. Among total 275 $A_2$ lines, phenotypic variants were found in six lines, 2.1% variant frequency. The diversity of $A_2$ lines derived from anther culture was different according to the cross combinations. Fruit color was within parental range, no transgressive variation was observed. However leaf color showed transgressive variation. In fruit length, fruit width and fruit weight, one C-HC $\times$ DGSH and DGSH $\times$ C-NH showed great diversity compared with doner parents while Cheokjo 1 $\times$ C-NH crossed with Cheokjo 1 with big fruit shape showed small diversity. Stem length to 1st branch was relatively similer to or longer than donor parents. Stem thick exhibited remarkable diversity. Node number to 1st branch distributed alomost within the range of donor parents in C-HC $\times$ DGSH combination, however great transgressive variations were observed in DGSH $\times$ C-NH and Cheokjo 1 $\times$ C-NH combinations.

• Polymer(Korea)
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• v.30 no.3
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• pp.247-252
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• 2006

The long-term use of indwelling urinary catheters can allow bacterial adhesion to their surfaces, followed by the catheter-associated urinary tract infection. In an attempt to minimize the bacterial adhesion, various amphiphilic polyurethanes (APUs) were synthesized as potential coating materials for urinary catheters. By varying composition of the soft segments such as PEO, PTMO, and PDMS, four different polyurethanes were synthesized. All the APU-coated urinary catheters had the smooth surfaces and showed higher hydrophilicity, compared to the commercial silicone catheters. In particular, the use of APUs with the higher PEG content significantly augmented hydrophilicity and remarkably reduced the total amount of bacteria adhering to the surface. Overall, the APUs prepared in this study provided the promising potential as coating materials for urinary catheters.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.4
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• pp.462-465
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• 1987

Three F$_1$ hybrids, Seokwang/Milyang 54, HR1619-6-2-1-2-2/Milyang 54 and 55061/IR19735-5-2-3-2-1, and their parents were inoculated with each of four individual blast races, IC-l3, IH-l, IA-61 and IB-47, and the mixtures of two races, IC-13 and IH-l, IC-13 and IA-61, and IC-13 and IB-47, respectively. The varietal reactions to the tested races showed that two parental varieties of each cross, Seokwang and Milyang 54, HR1619-6-2-1-2-2 and Milyang 54, and 55061 and IR19735-5-2-3-2-1 have different resistance gene(s) respectively. The F 1 hybrids between two cultivars having different resistant genes were resistant to the mixture of two races of which one race was virulent to one parent and avirulent to the other parent respectively, while the parents of these F$_1$s were susceptible. This may suggest that the F$_1$ hybrids have wider spectrum resistance to leaf blast than their parents.

• Journal of the Korean GEO-environmental Society
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• v.15 no.3
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• pp.15-19
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• 2014

Spilling pollutants and its contamination to the ground have serious impact to public resulting in various research about remediation techniques. In this study, the use of amphiphilic block copolymer for remediation was investigated with a series of laboratory tests on removal of hydrophobic contaminant in soil. Four types of amphiphilic block copolymer were developed and the efficiency of the cleaning was compared with surfactant using arbitrary diesel-contaminated soils. The results of the study show that the use of amphiphilic polymer in the soil washing process significantly enhanced the remediation of the contaminated soil and a potential of new methodology of eco-friendly remediation.

• Journal of the Korean Magnetics Society
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• v.20 no.6
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• pp.216-221
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• 2010

Magnetic nanocomposites contained iron oxide were synthesized by through cross-linking polymerization of dimethylacetamide (DMAc) solution and toluen solution on the amphiphilic polymer networks based on urethan acrylate nonionomer (UAN) precursor chains. For the study on microscopic structures and magnetic properties of the magnetic nanoparticles, FESEM and XRD and Mossbauer spectroscopy were used. The results investigated show that there are magnetic nanoparticles of $Fe_2O_3$ in samples and the magnetic nanocomposites contained iron oxide in polymer networks of UAN using DMAc solution are more smaller than using toluen solution. All of the Fe ions in the samples present $Fe^{3+}$ and the magnetic property of samples are paramagnetic by superparamagnetic effect at room temperature.

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.200-211
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• 1993

Somatic hybrids of Pleurotus florida ASI 2016 and Pleurotus ostreatus ASI 2018 were obtained by protoplast fusion. The 40 fusants($P1{\sim}P40$) was examined for the yield on fermented and pasteurized rice straw in a tray. The carpophore yield of them were showed as the range of $27.0{\sim}155.2$, based on parental values of 100(ASI 2018), The pilei of fusants between orange white colored P. florida and dark grey colored P. ostreatus had mixed colors in the young stage. Other breeding programmes were performed to improve new varieties with high yield and good quality. A new oyster mushroom variety, Wonhyeongneutaribeosus(P72), was developed at the Agricultural Sciences Institute, Rural Development Administration in 1990. This P.florida-ostreatus-ostreatus hybrid P72 was selected from 38 protoplast fusion products($P41{\sim}P78$) between P.florida-ostreatus recombinant P5-M 43-arg rib and P. ostreatus ASI 2-13-0 2001-19-pro orn. The yield indexes of 38 hybrids ranged $40.5{\sim}152.7$ compared with the parental values of 100(ASI 2001). Hybrid P72 was characterized by the large fruiting bundle of semispherical shape with long stipe and by the small and circular pileus, resulting in lower harvesting cost. A significant increase in carpophore production was observed in somatic hybrids of protoplasts due to heterosis. A comparision of hybrid with parents P72 was made using isozyme analysis. The esterase banding patterns could be characterized by new bands in the hybrids. Seven fusion products of four crosses between P.florida ASI 2016 and P. ostreatus ASI 2018 were analysed with respect to the distribution of progenies and segregation of gene markers by random basidiospore analysis. Segregation of alleles should yield progeny of four genotypes in a Mendelian ratio of 1 : 1 : 1 : 1 for prototrophs, auxotrophs of one parental type, auxotrophs of the other parental type, and auxotrophic recombinants, respectively. However, five fusants of them did not detect one parental, P.ostreatus, type. Basidiospores could yield progeny of 16 genotypes in the cross of one of the recombinant P5-M43-arg $rib{\times}P. ostreatus$ ASI 2-13-pro orn but the segregants of three fusants were not detected clearly. The allele ratio of loci could be expected 1 : 1 : 1 : 1 for arg, rib, pro and orn. The ratio, however, would be changed to 4 : 1 : 1 : 1 with increasing proportion of argo In almost all the fusants, prototrophic recombinants were recovered in large numbers against auxotrophic markers. Parental genotypes were recovered with the recombinant progeny amounting to $38.68{\sim}99.56%$. The analysis provides proof of heterokaryosis and strong evidence for haploidy of vegetative nuclei, a sexual cycle consisting of nuclear fusion and meiosis.