• Journal of Life Science
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• v.24 no.11
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• pp.1174-1179
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• 2014

This research was carried out to evaluate whether gamma ray is a useful tool for breeding new strains of mushrooms. For this research, 5 mutant groups, 20 strains of Hypsizigus marmoreus, 2 strains of Lyophyllum decastes, and 1 strain of Lyophyllum shimeji were used. Monokaryon spores from one variety of H. marmoreus were irradiated with 50~2,000 Gy of gamma ray. The propriety dose was 50~200 Gy for mutagenesis. Mutant monokaryon mycelia crossed each order to become dikaryon mycelia. The internal transcribed spacer (ITS) regions of rDNA were amplified using PCR, and the products were sequenced. The sequences of the ITS regions (16 partial rDNA, complete ITS1, 5.8 rDNA and partial rDNA) were analyzed by PCR, and strains of H. marmoreus, L. decastes, and L. shimeji were auto-sequenced. The lengths of the sequenced ITSs were 1,052~1,143 nucleotides. Genetic matrices were calculated using Nei-Li's genetic distance coefficient based on ITS sequence. The dissimilarities were 0~3.35% in strains of H. Hypsizigus. In addition, a phylogenetic tree was constructed based on ITS sequences using the neighbor-joining (NJ) method. The phylogenetic tree revealed that 23 strains and 5 mutant groups were divided into 12 clusters; the mutant groups fell into different clusters. These results show that mushroom spores were mutated effectively by gamma ray; therefore, gamma ray could be a useful tool for breeding new strains of mushrooms.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.4
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• pp.334-345
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• 2006

The objectives of this study were to analyze and compare 24 hrs personal exposure levels of MF at microenvironments such as home, school, educational institute, internet pc game room, transportation, and other places according to time activity patterns using various metrics for children attending the primary schools located near and away from the power lines, and to characterize the major microenvironments and impact factors attributed personal exposure level. The study was carried out for 44 children attending a primary school away from the lines(school A) and 125 children attending a school away from 154 kV power lines(school B), all who aged 12 years and were 6 grade, from July 2003 to December 2003. All participants filled in a questionnaire about characteristics, residence, use of electrical appliances and others. Children wore a small satchel in which EMDEX II and Lite (Enertech, Co. Ltd) and a diary of activity list for period of registration in 20 minutes blocks. All statistical calculations were made with the SAS System, Releas 6.12. The summary of results was presented below. First, about the characteristics of subjects, there no differences between two groups. The subject almost spent about 56 % of their time at home and about 20~25 % of their time at school. Fifty percent of children spent 2 hours at private educational institutes. Second, the personal exposure measurements of children in school B was statistically higher than those of children in school A by various metrics such as arithmetic mean, geometric mean, percentile(5, 25, 50, 75, 95), maximum, rate of change metric, constant field metric. The arithmetic and geometric mean magnetic fields during the time the children were at school B were 0.98 and $0.86{\mu}T$ and were about 23 times higher than those of children were at school A. In conclusion, the significant major determinants of personal exposure level is the distance from the power line to microenvironments.

• Korean Journal of Materials Research
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• v.20 no.11
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• pp.586-591
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• 2010

Solar cells have been more intensely studied as part of the effort to find alternatives to fossil fuels as power sources. The progression of the first two generations of solar cells has seen a sacrifice of higher efficiency for more economic use of materials. The use of a single junction makes both these types of cells lose power in two major ways: by the non-absorption of incident light of energy below the band gap; and by the dissipation by heat loss of light energy in excess of the band gap. Therefore, multi junction solar cells have been proposed as a solution to this problem. However, the $1^{st}$ and $2^{nd}$ generation solar cells have efficiency limits because a photon makes just one electron-hole pair. Fabrication of all-silicon tandem cells using an Si quantum dot superlattice structure (QD SLS) is one possible suggestion. In this study, an $SiO_x$ matrix system was investigated and analyzed for potential use as an all-silicon multi-junction solar cell. Si quantum dots with a super lattice structure (Si QD SLS) were prepared by alternating deposition of Si rich oxide (SRO; $SiO_x$ (x = 0.8, 1.12)) and $SiO_2$ layers using RF magnetron co-sputtering and subsequent annealing at temperatures between 800 and $1,100^{\circ}C$ under nitrogen ambient. Annealing temperatures and times affected the formation of Si QDs in the SRO film. Fourier transform infrared spectroscopy (FTIR) spectra and x-ray photoelectron spectroscopy (XPS) revealed that nanocrystalline Si QDs started to precipitate after annealing at $1,100^{\circ}C$ for one hour. Transmission electron microscopy (TEM) images clearly showed SRO/$SiO_2$ SLS and Si QDs formation in each 4, 6, and 8 nm SRO layer after annealing at $1,100^{\circ}C$ for two hours. The systematic investigation of precipitation behavior of Si QDs in $SiO_2$ matrices is presented.

• Journal of Applied Biological Chemistry
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• v.53 no.1
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• pp.25-30
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• 2010

This paper describes a simultaneous method for the determination of two aminoglycosides (neomycin and gentamicin) using solid phase extraction followed by liquid chromatograph-mass spectrometry. The extract was applied to an WCX and HLB solid phase extraction cartridge. The cartridges were washed with water and methanol, and analytes were eluted with TCA buffer-acetonitrile mixture. The aminoglycosides were separated by ion-pairing reversed phase mode prior to ESI-LC/MS. Under the conditions applied neomycin was almost separated from all the gentamicin compounds. No interfering peaks from endogenous compounds of matrix were noted at the elution position of the analytes. Recoveries of neomycin fortified at levels of 0.25, 0.5, 1.0 and 2.0 mg/kg seafood samples ranged from 92 to 115%. Recoveries of gentamycin fortified at levels of 0.05, 0.1, 0.2, 0.4 mg/kg seafood samples ranged from 99 to 116%. Method detection limits in four seafood sample matrices were between 0.002 and 0.033 mg/kg.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.1
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• pp.50-56
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• 2011

To make conservative port and coast ecosystems and creative the greenspace, We were investigated with characteristic of flora, environmental factors, types of port, adaptive species, minimum conservation area and plantation model. In 50 sites of study areas, there are 19 families and 174 species of vascular plants and 19 families and 48 species of halophytes. Dominant communities in port ecosystem contains Carex kobomugi community, Elymus mollis community, Carex pumila community, Ixeris repens community, Vitex rutundifolia community, Calystegia soldandlla community, Rosa rugosa community, Lathyrus japonica community, Salsola komarovi community, Cynodon dactylon community, Tetragonia tetragonioides community, Suaeda japonica community, Suaeda maritima community, Zoysia sinica community and Phragmites communis community. We carried out Canonical Correspondence Analysis(CCA) for ordinations on the vegetation and plant communities-environmental variable matrices in 50 sites. The communities tended to cluster into three types: Clay marsh, Sand marsh, Sand gravel marsh types. Adaptive species in habitate types are selected that sand marsh-type communities in ports contained Elymus mollis community, Ixeris repens community, Carex kobomugi community, Carex pumila community, Clay marsh-type communities contained Suaeda japonica community, Phragmites communis community, Zoysia sinica community and Suaeda maritima community, Sand gravel marsh-type communities contained Vitex rutundifolia community, Calystegia soldandlla community. We are conducted the estimation of minimal area for plantation of adaptive plant species and carried out guide line and plantation model for creation of green space in port ecosystem.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.1
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• pp.21-30
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• 2004

This study deals with free vibrations of laminated composite structures with a channel section using finite element method. In this paper, the mixed finite element method using Lagrangian and Hermite interpolation functions is adopted and a high-order plate theory is used to analyze laminated composite non-prismatic folded plates with a channel section more accurately for free vibration. The theory accounts for parabolic distribution of the transverse shear stress and requires no shear correction factors supposed in the first-order plate theory. An 32×32 matrix is assembled to transform the system element matrices from the local to global coordinates using a coordinate transformation matrix, in which an eighth drilling degree of freedom (DOF) per node is appended to the existing 7-DOF system. The results in this study are compared with those of available literatures for the conventional and first-order plate theory. Sample studies are carried out for various layup configurations and length-thickness ratio, and geometric shapes of plates. The significance of the high-order plate theory in analyzing complex composite structures with a channel section is enunciated in this paper.

• The KIPS Transactions:PartB
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• v.11B no.6
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• pp.653-660
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• 2004

Object-oriented analysis-synthesis coding (OOASC) subdivides each image of a sequence into a number of moving objects and estimates and compensates the motion of each object. It employs a motion parameter technique for estimating motion information of each object. The motion parameter technique employing gradient operators requires a high computational load. The main objective of this paper is to present efficient motion parameter estimation techniques using the hierarchical structure in object-oriented analysis-synthesis coding. In order to achieve this goal, this paper proposes two algorithms : hybrid motion parameter estimation method (HMPEM) and adaptive motion parameter estimation method (AMPEM) using the hierarchical structure. HMPEM uses the proposed hierarchical structure, in which six or eight motion parameters are estimated by a parameter verification process in a low-resolution image, whose size is equal to one fourth of that of an original image. AMPEM uses the same hierarchical structure with the motion detection criterion that measures the amount of motion based on the temporal co-occurrence matrices for adaptive estimation of the motion parameters. This method is fast and easily implemented using parallel processing techniques. Theoretical analysis and computer simulation show that the peak signal to noise ratio (PSNR) of the image reconstructed by the proposed method lies between those of images reconstructed by the conventional 6- and 8-parameter estimation methods with a greatly reduced computational load by a factor of about four.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.289-295
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• 1995

This study was carried out to develop a controlled-release insecticide formulation for the control of rose aphid (Macrosiphum ibarae) in rose and cotton aphid (Myzus persicae) in chrysanthemum (Dendranthema grandiflorum var. Meibung) in greenhouse. Imidacloprid[1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine] was chosen as a toxicant. Two synthetic polymers, low density polyethylene(LDPE) and ethylene vinyl acetate(EVA), were used as polymer matrices. The tested plastic sheet formulations were prepared by heat-aided extrusion procedures after mixing imidacloprid technical and the polymers of three different combinations, and physicochemical properties as well as efficacy of the formulations were investigated. The amounts of imidacloprid recovered and incorporated in the formulations were recorded over 90% and 80%, respectively. Release of the active ingredient from the formulations was remarkably affected by mixing rates of polymers. The active ingredient in the formulations was chemically unstable with over 10% degradation rates after 90 day storage at $50{\pm}2^{\circ}C$. The residual amounts of imidacloprid in the soil treated with the formulations were paralleled with the release pattern of the formulations. Efficacy of the formulations on rose and cotton aphid was maintained over 90% even 120days after treatment under greenhouse.

• Korean Journal of Environmental Biology
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• v.22
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• pp.30-37
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• 2004

Peysistent oyganochlorine compounds (OCs) weve determined in sediments and bivalves from Gwangyang Bay. The concentrations of ∑PCB, ∑DDT, ∑HCH and ∑CHL in sediments were in the range of f 2.25∼11.4 ng g$\^$-1/, 0.16∼1.16 ng g$\^$-1/, nd∼0.51 ng g$\^$-1/, and 0.05∼0.79 ng g$\^$-1/, respectively. The overall OCs concentrations in sediments were below the effect range -median (ER-M) values toy benthic organisms suggested by NOAA (1991). Levels of PCB compounds a re relatively lower than other industrialized bays (Pusan Bay, Ulsan Bay, and Youngil Bay). OCs accumulated in bivalves were higher than those in sediments. In bivalves, the concentration ranges of ∑PCB, ∑DDT, ∑HCH and ∑CHL were 9.97∼31.7 ng g$\^$-1/, 7.54∼22.6 ng g$\^$-1/, 0.49∼2.0 ng g$\^$-1/, and 0.82∼7.32 ng g$\^$-1/, respectively. Relatively high PCB concentrations in both environmental matrices are found at the inner bay than the outer part, indicating that the sources of PCBs were located inside the bay. DDT compound showed relatively high concentrations in the vicinity of the mouth of river and urban area, whereas other organochlorine pesticides show homogeneous distributions over the bay. Homologue profile of PCB compounds shows that low-chlorinated congeners (especially, di-, tyi- and tetra-) are abundant in Gwangynng Bay, which is diferent from other areas in Korea.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.269-280
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• 1998

Recently, application of composite materials such as fiber reinforced concretes(FRCs) and fiber reinforced plastics(FRPs) in conjunction with conventional structural components has become one of the main research areas. A proper use of advanced composite materials requires understanding their resistance mechanism and failure mode when they are applied to structures or their components. Particular considerations are given in this research to develop an analytical model which can predict the nonlinear flexural responses of bonded and unbonded prestressed concrete beams possibly having layers of different cementitious composite matrices in a section and/or FRP tendons. The block concept is used, which can be regarded as an intermediate modeling method between the couple method with one block and the layered method with multiply sliced layers in a section. In order to find a particular deflection point of a beam under load, solutions to the 2N-variables are found numerically by using approximate N-force equilibrium equations and N-moment equilibirum equations. The model is shown to successfully predict the flexual behavior of variously reinforced bonded and unbonded prestressed concrete beams. The model is also successful in simulating a gradually increasing load after sudden drop inload resistance due to fracture of one or more FRP tendons. This feature is useful in tracing the overall load-deflection response of a beam prestressed with brittle FRP tendons.