• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.185-194
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• 2004

It is difficult to analyze and predict the long-term behavior of concrete structures and members under multiaxial stresses because most of existing researches on creep of concrete were mainly concerned about uniaxial stress state. Therefore, the main objective of this paper is the investigation of creep properties of concrete under multiaxial stresses. This paper presents experimental study on creep of concrete under multiaxial compression. Twenty seven cubic specimens($20{\times}20{\times}20 cm$) for three concrete mixes were tested under uniaxial, biaxial, and triaxial stress states. Creep strains were measured in three directions of principal stresses. Poisson's ratio at the initial loading was obtained, as was Poisson's ratio due to creep stain and Poisson's ratio due to the combined creep strain and elastic strain. These Poisson's ratios were approximately equal for each concrete mix. The Poisson's ratio at the initial loading and the Poisson's ratio for the combined strain Increased slightly as the strength of the concrete increased. In addition, the volumetric creep strain and deviatoric creep strain were linearly proportional to volumetric stress and deviatoric stress, respectively.

• Journal of The Korean Association For Science Education
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• v.40 no.4
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• pp.359-374
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• 2020

This study is a complex type consisting of survey study and self-study. The former investigated elementary teachers' epistemological beliefs on convergence knowledge and teaching. As a representative of the result of survey study I, as a teacher as well as a researcher, was the participant of the self-study, which investigated my epistemological belief on convergence knowledge and teaching and my execution of convergent science teaching based on family resemblance of mathematics, science, and physical education. A set of open-ended written questionnaires was administered to 28 elementary teachers. Participating teachers considered convergent teaching as discipline-using or multi-disciplinary teaching. They also have epistemological beliefs in which they conceived convergence knowledge as aggregation of diverse disciplinary knowledge and students could get it through their own problem solving processes. As a teacher and researcher I have similar epistemological belief as the other teachers. During the self-study, I tried to apply convergence knowledge system based on the family resemblance analysis among math, science, and PE to my teaching. Inter-disciplinary approach to convergence teaching was not easy for me to conduct. Mathematical units, ratio and rate were linked to science concept of velocity so that it was effective to converge two disciplines. Moreover PE offered specific context where the concepts of math and science were connected convergently so that PE facilitated inter-disciplinary convergent teaching. The gaps between my epistemological belief and inter-disciplinary convergence knowledge based on family resemblance and the cases of how to bridge the gap by my experience were discussed.

• Journal of Bio-Environment Control
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• v.19 no.1
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• pp.1-5
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• 2010

This research was conducted to investigate difference of internal temperature, humidity, and plant growth according to covering materials in sweet pepper's greenhouse. For growing period, daily mean internal temperature was not different between glass (GH) and plastic film house (PH), but the changed volume was more PH than GH. Internal humidity deficit was more PH than GH as that was 4.3 $g{\cdot}m^{-2}$ and 5.6 $g{\cdot}m^{-2}$, respectively. In change of internal temperature effected by different intensity of external light, that of PH was fasted twice that of GH, and that's tendency was effected by difference of internal temperature for several hours after sunrise. Leaf growth and photosynthetic product were more GH than PH, productivity of GH was better 80 percents than PH. As results, To improve productivity in PH compared with productivity in GH need to be the detailed managements of internal environmental factors in early period after sunrise.

• Applied Microscopy
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• v.38 no.1
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• pp.51-61
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• 2008

This simulation study examined the effect of data acquisition error including the data type of TEM image, and incident beam intensity of the tilt series on 3D tomograms. Simulation was performed with the 3D head phantom model of Kak and Slaney, and the slightly modified 3D head phantom model with enhanced difference in absorption coefficients. Reconstructed tomogram for the original head phantom model using 8-bit gray-scale image was distorted with extremely high level of noise, while an acceptable result was obtained for the modified model. The results for the original model using wrong formulation for the transmitted beam intensity was proved to be incorrect. The high level of noise along the z direction was found in case of the modified model. On the other hand, the wrong value of incident beam intensity in both models gave distorted results. In order to reconstruct an artifacts-free 3D structure from the projections with invisible features in electron tomography, the 16-bit projection images should be used with the correct incident beam intensity which is applied to Beer's law.

• Korean Journal of Plant Tissue Culture
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• v.27 no.6
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• pp.453-459
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• 2000

Three rice (Oryza sativa L. var Dong-Jin) mutants (DTR1, DTR2, DTR3) resistant to S-methyltryptophan (5MT) were selected by mutagenized M3 seeds. The frequency of chlorophyll mutations induced by the EMS (0.2%) treatment performed 2 hours after flowering is clearly higher than that induced by other treatments in M1 generation. Progeny obtained from the self-pollinating of 5MT-resistant lines segregated with 3 : 1 of resistant to sensitive ratio. Furthermore, the ratio of homozygote to heterozygote in 5MT-resistant plants of the M4 generation was 1：2. These results show that 5MT resistance was inherited as a single dominant nuclear gene. The resistance was also expressed in callus derived from seeds. Total free amino acid content in homozygous seeds of DTR1 and DTR2 showed about 1.7 fold-increased compared to the wild-type seeds. In particular, the levels of phenylalanine and Iysine were, respectively, 6.2 and 3.2 times higher than those in the wild-type seeds. However, seeds of DTR3 had lower levels of free amino acid than the wild-type seeds. This result indicate that these mutants as a significant step towards the production of new rice with balanced amino acid content.

• Journal of Plant Biotechnology
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• v.40 no.4
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• pp.192-197
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• 2013

This study examined the phenotypic and molecular characteristics of the $2^{nd}$ clone ($T_0V_2$) plants of LeLs-antisense gene-transgenic chrysanthemum line (LeLs80) that exhibited non-branching, proving the relevance of these characteristics as a factor for use in environmental risk assessment. Results of the Southern blot analysis showed that three copies of the LeLs-antisense gene were introduced into the transgenic line, and northern analysis showed that the transcripted gene was normally expressed in the transgenic line. A flanking T-DNA sequencing method was used to determine that sequences of 184 and 464 bps flanked the LeLs-antisense gene in the transgenic line. These sequences, respectively, matched the 35S promoter for expression of the npt II gene and the NOS terminator for expression of the LeLs-antisense gene within the pCAMBIA 2300 vector.

• Research in Plant Disease
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• v.23 no.1
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• pp.75-81
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• 2017

In May 2016, 24 peach samples showing abnormal and virus like symptoms were collected in one of major peach producing area, Yeongcheon-si, Gyeongsangbuk-do, Korea. We performed RT-PCR diagnosis for confirmation of viral infection. The diagnostic targets are 17 species of viruses and viroids that quarantine and high risk pathogens when it occur. As a results, seven species of viruses and viroids, including an unreported (Apricot pseudo-chlorotic leaf spot virus, APCLSV) and a quarantine (Peach latent mosaic viroid, PLMVd) species in Korea, were detected. For the sequence analysis of unreported virus, APCLSV, the sequence of coat protein gene were amplified and cloned. The sequence showed 97% nucleotide identity with other APCLSV isolates and compared with other seven species of reported Trichoviruses. This virus was classified as APCLSV based on the sequence and phylogenetic analysis. This isolate was named Yeongcheon. As patterns of APCLSV occurrence, all samples that APCLSV detected were co-infected with Apple chlorotic leaf spot virus (ACLSV). As properties of ACLSV, APCLSV has high possibility of wide spread disease in fruit tree farms in Korea. Therefore, it is necessary to do related researches, such as infection route and influence of disease in commercial orchards.

• Korean Journal of Ecology and Environment
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• v.53 no.1
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• pp.102-108
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• 2020

This study is to analyze the growth response of the Quercus dentata seedlings to four environmental factors and measure the ecological niche breadth. Environmental factors were light, moisture content, soil texture, and organic matter, treated with four gradients. The more quantity light increased, the heavier the leaves biomass, aboveground biomass, belowground biomass and plant biomass was. In treatment of water content and soil texture, growth response was no difference. The more organic matter increased, the heavier aboveground biomass was, but the remaining trait of plant was no difference. The ecological niche breadth was 0.865 in light, 0.995 in moisture content, 0.994 in soil texture and 0.988 in nutrient. Ecological niche breadth was the widest in the moisture content treatment and the narrowest in the light treatment. This means that the growth of Q. dentata seedlings grows well as the amount of light increases, and is sensitive to light, Thus, it is determined a growth and ecological niche breadth by light factors.

• Membrane Journal
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• v.16 no.3
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• pp.221-229
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• 2006

This study is about the preparation and characterization of sulfonated random copolymer membranes containing perfluorocyclobutane (PFCB), fluorenyl, and sulfonyl units. The polymers were prepared through three synthetic steps, that is, the synthesis of a trofluorovinylether-terminated monomer, its thermal polymerization, and post-sulfonation using chlorosulfonic acid. A series of sulfonated random copolymers with different ion exchange capacity (IEC) were prepared by changing contents of fluorenyl uints in polymers with fixed molar ratio of chlorosulfonic acid during the post-sulfonation reaction. All the synthesized compounds were characterized by FT-lR, $^1H-NMR$, $^{19}F-NMR$, and Mass spectroscopy. As the content of sulfonated fluorenyl units increased, the IEC, water uptake, and ion conductivity of the sulfonated random copolymer membranes increased. The sulfonated random copolymer S-1 and S-2 showed higher values of ion conductivity than the Nafion-115 in a wide range of temperatures ($25{\sim}80^{\circ}C$).

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.1
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• pp.44-48
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• 2015

Mucopolysaccharidosis (MPS) IIIA is a lysosomal storage disorder caused by abnormalities of the enzyme Heparan N-sulfatase that is required for degradation of heparan sulfate. The patient in this study was a 5 year-old boy who presented with macrocephaly and developmental delay. Urinary excretion of glycosaminoglycan was increased (26 g/moL creatinine, reference range: <7 g/moL creatinine) and a distinct band of heparan sulfate was shown in electrophoresis. Heparan N-sulfatase activity was significantly decreased in skin fibroblasts (0.2 pmoL/min/mg protein, reference range: 9-64 pmoL/min/mg protein). PCR and direct sequencing analysis of the SGSH gene showed compound heterozygous mutations: c.1040C>T (p.S347F) and c.703G>A (p.D235N). This is the first report for a Korean patient with MPS IIIA who was confirmed by biochemical investigation and molecular genetic analyses.