• Title/Summary/Keyword: Half b - separated

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Electronic Structure and Magnetism of CrP/SrBi Interface: A First Principles Study

  • Bialek, Beata;Lee, Jae-Il
    • Journal of Magnetics
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    • v.12 no.3
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    • pp.93-96
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    • 2007
  • We investigated the electronic structure and magnetic properties of zinc-blende CrP/SrBi interface by using the all-electron full-potential linearized augmented plane wave method within the generalized gradient approximation. It is found that the half-metallicity is destroyed when the two half-metals are in contact. Magnetic moments of the atoms forming the supercell differ considerably from the respective values obtained for the bulk structures of the two materials. Cr atoms being and not being in contact with Bi atoms have magnetic moment 3.43 and $2.69{\mu}_B$, respectively. Bi atoms lose their majority electrons which results in their negative polarization. Alkaline Sr atoms are very weakly negatively polarized. The spin distribution within the supercell is such that well separated regions of positive and negative polarization are seen, especially around the layer of P atoms being in contact with the layer of Sr atoms.

A Permeability Measurement of Small Unilamellar Vesicles by 6-Carboxyfluorescein$^*$

  • Lee, Choong-Hee;Choi, Myung-Un
    • Bulletin of the Korean Chemical Society
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    • v.5 no.4
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    • pp.154-158
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    • 1984
  • In order to characterize the permeability of small unilamellar vesicles (SUV), efflux of 6-carboxyfluorescein (6-CF) from the vesicles was monitored spectrophotofluorometrically. Since the entrapped highly quenched 6-CF (200 mM) became fluorescent upon release from the vesicles, the 6-CF could be used as an efflux probe. SUV containing entrapped 6-CF was prepared from egg phosphatidylcholine and separated by gel filtration on Sepharose 4B. Observed change of relative fluorescent intensity with time was sigmoidal. From this curve, the parameter of permeability was determined either by half-time or a released amount per unit time from the initial slope. Half-time of efflux of prepared SUV having 302 ng phospholipid/ml in 10 mM Tris-HCl buffer pH 7.4 was 21.0 min at $37{\circ}C$. Various factors which could affect the half-time were examined including temperature, pH, salt, and vesicle concentration. In particular the effect of vesicle concentration on the efflux revealed that the permeability can be a function of the concentration.

Analysis of Half-life Time and Residual Concentration of Ethalfluralin Herbicide in Soils (토양 중 제초제 Ethalfluralin의 잔류 농도와 반감기 분석)

  • Han, Seong Soo;Rim, Yo Sup;Kim, Il Kwang
    • Analytical Science and Technology
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    • v.10 no.3
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    • pp.168-178
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    • 1997
  • The optimum conditions for the residual analysis of the ethalfluralin herbicide on soils were investigated and the residues in soils were determined by gas chromatography with electron capture detector(GC-ECD). The soil samples extracted with methanol and dichloromethane and concentrated. The concentrated phase were redissolved with toluene and analyzed with GC-ECD after separated by cyanosilica gel Sep-Pak cartridge. From the standard addition experiments with 0.1 and 1.0ppm, the average recoveries were 92.8~101.2% and the detection limit was 0.004ppm. The half-life time of ethalfluralin in the soil(A) was 35 days in the laboratory and 7.2 days in the field test whereas it was 45 days and 9.7 days for each in case of soil(B).

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Two new free-living marine nematodes of the genus Belbolla (Nematoda, Enoplida, Enchelidiidae) from a shallow subtidal benthic habitat of the outermost islands of Korea

  • Hyun Soo Rho;Hyo Jin Lee;Heegab Lee;Chang Geun Choi
    • Korean Journal of Environmental Biology
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    • v.39 no.4
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    • pp.423-434
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    • 2021
  • Two new free-living marine nematodes of the genus Belbolla Andrássy, 1973 belonging to family Enchelidiidae are newly described based on specimens obtained from a shallow subtidal sediment of the western and southern outermost islands of Korea. Belbolla koreensis sp. nov. differs from other species of the genus by the combination of the following characteristics: longer body length (3,080-3,462 ㎛ long), eight oesophageal bulbs in the posterior region of pharynx, well-developed two winged precloacal supplements (anterior precloacal supplement slightly longer than posterior one: 47-59 ㎛ vs. 43-46 ㎛ long), strongly arcuated, very thick, L-shaped spicule (122-127 ㎛ long, 1.7-1.9 anal body diameter(a.b.d.) long) with three separated blunt distal tips, and well-developed relatively long cylindrical shaped gubernacular apophysis with blunt teeth covering two thirds of the dorsal margin (57-58 ㎛ long, 0.8-0.9 a.b.d. long). Belbolla hoonsooi sp. nov. is characterized by the following combination of characteristics: longer body length (3,494 ㎛ long), eight oesophageal bulbs in the posterior region of pharynx, well-developed two winged precloacal supplements (anterior precloacal supplement slightly longer than posterior one: 43 ㎛ vs. 36 ㎛ long), strongly arcuated, L-shaped spicule (119 ㎛ long, 1.5 a.b.d. long) with three separated blunt distal tip, and well-developed relatively long inverted triangle shaped gubernacular apophysis with blunt teeth covering half of the dorsal margin (45 ㎛ long, 0.6 a.b.d. long). Detailed morphological characteristics and illustrations of two new Belbolla nematodes from the Korean seawaters were provided by differential interference contrast microscopy. Comparative tables on biogeographical and morphological characteristics of Belbolla species are also provided herein.

Evaluation of the Thermal Properties of Disposable Coveralls for Railroad Carriage Maintenance Workers (철도 차량 정비 작업자를 위한 일회용 부직포 작업복의 온열적 성능 평가)

  • 최정화;이주영;김소영
    • Journal of the Korean Society of Clothing and Textiles
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    • v.28 no.8
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    • pp.1175-1185
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    • 2004
  • This study evaluated thermo-physiological and subjective properties of improved disposable coveralls for railroad carriage maintenance through climatic chamber trials and a filed study. Subjects wore five kinds of disposable coveralls (Type A: a disposable coverall on the market, Type B: a coverall with an improved hood and size-adjustable design, Type C: a coverall with a portable hood, Type D: a coverall with small holes for ventilation, Type E: a sleeveless coverall, Type F: a separated type of coverall with half sleeves) The air temperature in the climatic chamber was set in 9$^{\circ}C$ and 30$^{\circ}C$ For each condition, subjects simulated the railroad work for 120min. and rectal temperature, skin temperatures, clothing microclimate and subjective sensations were measured. The results of chamber trials showed rectal temperature and clothing microclimate did not display significant differences by clothing type. In 30$^{\circ}C$ air temperature, mean skin temperature was higher in Type E and Type F than in Type A(p<0.05) but between the improved coveralls(B-F), we could not find any significant difference. In the case of thermal comfort, the most preferred types were Type B and Type C in 9$^{\circ}C$ and Type F in 30$^{\circ}C$. All subjects felt more comfortable in the improved coveralls than in coveralls of the market (Type A). In field study, workers preferred Type B, Type C and Type F to Type A but the most favorite type differed by the specific type of work. Especially, workers were dissatisfied that Type D tore easily due to lots of small holes around the armpits and Type I did not protect workers' shoulder and arms from oil contamination. According to the climatic chamber trials and field study, the most effective coveralls were Type B and Type C for winter and Type F for summer.

Fumigant Activity of Essential Oils and Components of Illicium verum and Schizonepeta tenuifolia Against Botrytis cinerea and Colletotrichum gloeosporioides

  • Lee, Sun-Og;Park, Il-Kwon;Choi, Gyung-Ja;Lim, He-Kyoung;Jang, Kyong-Soo;Cho, Kwang-Yun;Shin, Sang-Cheol;Kim, Jin-Cheol
    • Journal of Microbiology and Biotechnology
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    • v.17 no.9
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    • pp.1568-1572
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    • 2007
  • To develop a natural fungicide against Botrytis cinerea and Colletotrichum gloeosporioides, a total of 25 essential oils were tested for their fumigant activity against post-harvest pathogens. The vaporous phases of oils were treated to each fungus on potato dextrose agar medium in half-plate separated Petri plates at $10\;{\mu}g$ per plate. The essential oil of Illicium verum strongly inhibited the mycelial growth of both B. cinerea and C. gloeosporioides by over 90%. On the other hand, the essential oil of Schizonepeta tenuifolia showed inhibitory activity against mycelial growth of only B. cinerea by over 90%. Gas chromatography-mass spectrometry and bioassay indicated trans-anethole in I. verum and menthone in S. tenuifolia as a major antifungal constituent. The essential oils of I. verum and S. tenuifolia and their major constituents could be used to manage post-harvest diseases caused by B. cinerea and C. gloeosporioides.

A Retinoid Antagonist Inhibits the Retinoic Acid Response Element that Located in the Promoter Region of the Cytomegalovirus

  • Lee, Mi-Ock;Ahn, Ju-Mi;Han, Sun-Young
    • Biomolecules & Therapeutics
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    • v.6 no.3
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    • pp.276-282
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    • 1998
  • Retinoids regulate a wide variety of biological processes such as cellular proliferation and differentiation in many cell types. They have also shown to stimulate replication of several viruses including human cytomegalovirus (CMV). Retinoid signalling pathway involves two distinct subfamilies of nuclear receptors, retinoic acid receptors (RARs) and retinoid X receptors (RXRs) that bind to specific retinoic acid response elements (RAREs) in the promoter regions of retinoid-target genes. Here, we characterized RAREs in the regulatory regions of the CMV and of the hepatitis B vi.us (HBV). The viral RAREs, i.e., CMV-RARE and HBV-RARE, are composed of two consensus RARE half-sites (A/GGGTCA) arranged as a direct repeat separated by 5-bp and 1-bp, respectively. The RAREs were activated by both RAR/RXR heterodimers and RXR homodimers in transient transfection experiments. We also found that COUP-TF$\alpha$ (chicken ovalbumin upstream promoter-transcription factor u) and COUP-TF$\beta$ repressed the retinoid response of the viral elements. Further we demonstrated that previously known retinoid antagonist, SRI 1330, repressed retinoid-induced transactivation of the CMV-RARE. These results implicate Vitamin A, it's nuclear receptors and COUP-TFs as important regulators of the CMV and HBV pathogenesis and the SRl1330 as potential negative modulator of such retinoid-dependent processes.

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Numerical Modeling of Heat Transfer Due to Particle Impact on a Wall (벽면에서의 입자 고찰에 의한 열전달 수치 모델)

  • 권오붕
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.31 no.3
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    • pp.296-305
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    • 1995
  • A numerical study was undertaken to clarify the mechanisms of heat transfer in fluid-particle suspension flows. Such flows, including fluidization, are of considerable industrial importance. The present study uses 2-D numerical computations of collisions of normal incidence between a particle and a wall. By comparing the results using (a) adiabatic boundary conditions on the particle and (b) uniform, elevated temperature conditions on the particle, the contributions of fluid-mediated conduction and particle induced convection were successfully separated. Computational expedience led to the use of a transient conduction thermal layer as the background thermal field for the analysis. The results shows that the effect of particle movement is very small until the particle reaches a distance of one to one half diameter away from the wall. The gas-mediated conduction effect is dominant over the induced gas convection effect when Pe is small and the induced gas convection effect becomes significant as Pe increases.

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A Study on the Range of Color Preception in Primary Colors (1차색의 지각범위에 관한 연구)

  • 이정옥;정용희;이순자
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.13 no.4
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    • pp.7-13
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    • 1999
  • The purpose of this study was to suggest the c1ata which were useful to apply the color for clothes resign 29 female university students were se10cted in this experirrental study for the perception scope of primroy color from July to Dec. in 1998. The results of this study are as the following : 1) The perception scope of red perceived by more than 30% of the subjects was wider in Chroma-axis than in Value-axis, including 5R 4/12, 5R 4/10 and 5R 5/14 in standard color 5R standard color 5R 4/14. The perception scope of yellow was wider in Chroma-axis in standard color 5Y 8/14. And the perception scope of blue was wider in Value-axis in standard color 5B 4/10. 2) In chromaticity diagram, the perception scope of red perceived by one subjoct and over was large, covering three-quarters and being extended in X -axis. The perception scope of yellow was awuximately a half, without being linked together. A few of it were separated. And the perception scope of blue was about two-thirds, including all color chips in the line. In conclusion, the perception scope of red was comprehensively broad and there aweared relatively strong corrnron feature between the subjects. The perception scq;e of yellow was awuximate1y a half and there was little cormnon feature between the subjects. And the perception sccpe of blue was sorrewhat wide and the sUbiects expressed strong cornrmn feature. feature.

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