• Journal of Microbiology and Biotechnology
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• v.23 no.8
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• pp.1107-1115
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• 2013

The Cyt1Aa protein of Bacillus thuringiensis susbp. israelensis elaborates demonstrable toxicity to mosquito larvae, but more importantly, it enhances the larvicidal activity of this species Cry proteins (Cry11Aa, Cry4Aa, and Cry4Ba) and delays the phenotypic expression of resistance to these that has evolved in Culex quinquefasciatus. It is also known that Cyt1Aa, which is highly lipophilic, synergizes Cry11Aa by functioning as a surrogate membrane-bound receptor for the latter protein. Little is known, however, about whether Cyt1Aa can interact similarly with other Cry proteins not primarily mosquitocidal; for example, Cry2Aa, which is active against lepidopteran larvae, but essentially inactive or has very low toxicity to mosquito larvae. Here we demonstrate by ligand binding and enzyme-linked immunosorbent assays that Cyt1Aa and Cry2Aa form intermolecular complexes in vitro, and in addition show that Cyt1Aa facilitates binding of Cry2Aa throughout the midgut of C. quinquefasciatus larvae. As Cry2Aa and Cry11Aa share structural similarity in domain II, the interaction between Cyt1Aa and Cry2Aa could be a result of a similar mechanism previously proposed for Cry11Aa and Cyt1Aa. Finally, despite the observed interaction between Cry2Aa and Cyt1Aa, only a 2-fold enhancement in toxicity resulted against C. quinquefasciatus. Regardless, our results suggest that Cry2Aa could be a useful component of mosquitocidal endotoxin complements being developed for recombinant strains of B. thuringiensis subsp. israelensis and B. sphaericus aimed at improving the efficacy of commercial products and avoiding resistance.

• Journal of the Korean Magnetics Society
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• v.4 no.3
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• pp.256-262
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• 1994

$200{\AA}$ thick Co/Pd multilayered thin films were fabricated by sputtering. Two thicknesses of cobalt sublayer, $2{\AA}$ and $4{\AA}$ were chosen and the effects of sputtering pressure on the perpendicular magnetic anisotropy were investigated. It has been found that the optimum pressure for maximum perpendicular magnetic anisotropy(PMA) existed and the pressure for maximum PMA was lower for the multilayer with $2{\AA}$ cobalt layer than that with $4{\AA}$ cobalt thickness. As the sputtering gas presssure increased, domain wall motion with magnetization became difficult and the predominant mode of magnetization reversal changed from domain wall motion to magnetic moment rotation. It turned out that the perpendicular magnetic anisotropy was higher in case of $2{\AA}$ cobalt thickness than $4{\AA}$ cobait thickness.

• Journal of the Mineralogical Society of Korea
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• v.2 no.1
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• pp.18-25
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• 1989

The X-ray diffraction and electron microscopy study of the kaolin sample from Sancheong area show that the halloysite occurs as hydrated 10$\AA$ form. It implies that the 7$\AA$ reflection and hk-line splitting in the X-ray diffractogram are ascribed to kaolinite. Kaolinite in Sancheong kaolin is of a disordered type. It tends to be enriched in the colored part of kaolin samples. Quantitative analyses show that kaolin contains 16-57% halloysite and 10-55%kaolinite.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.12
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• pp.18-23
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• 2000

In this paper, we propose the organic light-emitting devices with vacuum evaporated ultrathin CsF layer between the AI electrode and conjugated polymer MEH-PPV which was spin coated. In this structure, the CsF layer will be well transferred the electron injection from the electrode to the emission layer MEH-PPV. Finally this structure enhances the emission efficiency of the organic light-emitting device. And we measured the I-V-L properties with the split of CsF thickness into the $2{\AA},\;4{\AA},\;8{AA},\;10{\AA},\;20{\AA},\;50{\AA},\;75{AA}$ respectively. And also we evaporated CsF/Al, CsF/Au Cs/Au electrode respectively for the comparison. As the results, we obtained the maximum quantum efficiency 0.6% at $4{\AA}$ CsF thickness and then at $8{\AA}$, it decreased a little but it's still better than pure Al electrode which has 0.01%.

• Journal of the Korean Society of Safety
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• v.28 no.6
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• pp.17-22
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• 2013

The production of flame-retardant polypropylene powder coating with the addition of flame retardant (PP) controlled rheology (CR) and polypropylene, were discussed comparing the mechanical properties, such as safety and topical coating properties. Mechanical properties measurements showed almost the same as AA-1 where the flame retardant is not added. These results appear to, and because it is excellent in compatibility with polypropylene and flame retardant. Physical properties of the coating film, a test piece flame retardant organic is added, although it shows the physical properties of the coating film was stable, did not show the physical properties satisfactory is the test piece flame retardant of weapons has been added. In the safety of the topic, AA-4, AA-5 the results of thermal analysis but it is excellent, the LOI is excellent in 27.8 vol% 27.0 vol% in AA-4 and AA-2, AA-3, and 27.4 vol%, did not show many obstacles flame AA-5 result UL94.

• Journal of the Korean Chemical Society
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• v.7 no.1
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• pp.74-84
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• 1963

Hexamethylenediamine dihydroiodide is monoclinic, with cell dimensions $a=4.85{\AA}$, $b=12.77{\AA}$, $c=9.73{\AA}$, ${\beta}=91.5^{\circ}$ The space group is $P2_1/c$, with two molecules per unit cell. It has a center of symetry in the molecule. All atomic positions are determined by means of a two-dimensional patterson synthesis and fourier synthesis. The C-N bond distance is $1.48{\AA}$ and the C-C bond distances are lying between $1.55{\AA}$, and $1.59{\AA}$. The iodine atom is bonded by hydrogen bridges of $3.59{\AA}{\pm}0.1{\AA}$ to nitrogen atoms and surrounded by three nitrogen atoms. The hexamethylenediamine chain is zigzag in the hexamethylenediamine dihydrochloride molecules though, it is not zigzag in the hexamethylenediamine dihydroiodide.

• Journal of the Korean Magnetics Society
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• v.9 no.5
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• pp.251-255
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• 1999

NiFe(60 $\AA$)/Co(0$\AA$$\leq$x$\AA$$\leq$15$\AA$)/Cu(60$\AA$)/Co(30$\AA$) spin valve thin films were prepared on 4$^{\circ}$ tilt-cut Si(111) substrates with a 50 $\AA$ thick Cu underlayer without applying any external magnetic field during the deposition, and the effects of inserted ultrathin Co layer on magnetic anisotropy and GMR properties of the NiFe(60 $\AA$)/Cu(60$\AA$)/Co(30$\AA$) spin valves were investigated. As the ultrathin Co layer was inserted into the NiFe/Cu interface of the spin valves, GMR ratio was increased from about 1.5% to 3.5%, and the easy axis of NiFe(60 $\AA$) layer was rotated by 90$^{\circ}$. Accordingly, it was aligned along the same direction with the easy axis of Co(30 $\AA$)layer. Therefore, squared R-H curves was obtained in the spin valves, which is favorable properties for the digital GMR devices such as MRAM. In order to investigate the change of magnetic anisotropy of NiFe layer of the spin valves in more details,XRD measurement was performed using NiFe(500 $\AA$) and NiFe(500 $\AA$)/Co(10 $\AA$) thin films on the same templates. Strong (220) NiFe peak was observed in both films regardless of the inserted Co layer, so it was thought that the variation of magnetic anisotropy of NiFe layer is from the interface effect, the change of interface from NiFe/Cu to NiFe/Co, rather than the volume effect such as the change of magnetocrystalline effect.

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.485-492
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• 2006

The AA5182/polypropylene/AA5182(AA/PP/AA) sandwich sheets have been developed for application to automotive body panels in future lightweight vehicles with significant weight reduction. It has been reported that the AA5182 aluminum sheet shows $L\"{u}ders$ band because of dissolved Mg atoms that cause fabrication process problem, especially surface roughness. The examination of serration behavior has been made after the tensile deformation of the AA/PP/AA sandwich sheets as well as that of the AA5182 aluminum skins at room and elevated temperatures. All sandwich sheets and the AA5182 aluminum skin showed serration behavior on their flow curves. However, the magnitude of serration was significantly diminished in the sandwich sheet with high volume fraction of the polypropylene core. According to the results of the analysis of the surface roughness following the tensile test, $L\"{u}ders$ band depth of the sandwich sheet evidently showed lower than that of the AA5182 aluminum skin. The strain rate sensitivity, m-value, of the AA5182 aluminum skin was -0.006. By attaching these skins to the polypropylene core, which has relatively large positive value of 0.050, m-value of the sandwich sheets changed to the positive value. The serration mechanism of the sandwich sheets was quantitatively investigated in the point of the effect on polypropylene thickness variation, that on the strain rate sensitivity and that on the localized stress state.

• Journal of Astronomy and Space Sciences
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• v.24 no.1
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• pp.55-68
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• 2007

We carried out a validation study on AURIC FUV/EUV dayglow calculation with $OII\;834{\AA},\;OI\;989{\AA},\;OI\;1027{\AA},\;NII\;1085{\AA},\;NI\;1134{\AA},\;NI\;1200{\AA},\;OI\;1304{\AA},\;OI\;1356{\AA}$ dayglows observed by STP78-1 satellite. Comparison between calculated and observed values indicates that they are in agreement within about 20% for dayglows of $OII\;834{\AA},\;OI\;1027{\AA},\;NI\;1200{\AA},\;OI\;1304{\AA}$. However, the calculated intensities of $OI\;989{\AA},\;NII\;1085{\AA},\;NI\;1134{\AA}$ are only 42, 74 and 45% of the observed values, respectively, showing serious differences from the observation. It was surmised that the differences in $OI\;989{\AA}\;and\;NI\;1134{\AA}$ are due to incomplete calculation of radiative transfer and uncertain photochemical processes in AURIC model, respectively. The difference in $NII\;1085{\AA}$ is conjectured to be due to variation of the input solar EUV flux rather than due to AURIC model itself. For up-looking dayglows from the satellite, the calculated values from AURIC are all less than those of STP78-1, which may imply that AURIC model does not include dayglow contribution from regions below the satellite altitude when it computes dayglows in up-looking direction. The differences are particularly serious for $OI\;989{\AA},\;NI\;1134{\AA},\;NI\;1200{\AA}$ dayglows. The calculated latitudinal variation of $OII\;834{\AA}$ dayglow is also significantly different from the observed one, especially at mid-latitude regions. This may be due to inability of MSISE-90 (in input of AURIC) to simulate oxygen atom densities at mid-latitudes during auroral storms at those days of STP78-1 observations. Our findings of the validation study should be resolved when AURIC model is revised in future.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.11
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• pp.1146-1152
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• 2005

Graft copolymers were synthesized from methylcellulose(MC) and acrylic acid(AA) with active carboxyl groups in the presence of potassium persulfate($K_2S_2O_8$) initiator to enhance adsorption capacity of toxic heavy metal such as $Pb^{2+}$ and $Cu^{2+}$ from wastewater. The resulting grafted copolymers(MC-g-AA/PAA) were mixture of the graft copolymers from MC and AA(MC-g-AA) and polyacrylic acid homopolymers(PAA). The degree of palling was increased with rising concentration of monomer and initiator under the reaction conditions at $60^{\circ}C$, 3 hrs. The water insoluble property of MC-g-AA showed more than 19.7% degree of grafting. So that it could be an adsorbent of heavy metals. Adsorption characteristics of the MC-g-AA were evaluated depending on the degree of grading, pH of wastewater, adsorption time, dosage of MC-g-AA and concentration of heavy metals in the different conditions. Degree of grafting, and initial concentration of heavy metal ions increased, the adsorption amount of $Pb^{2+}$ and $Cu^{2+}$ increased, but added MC-g-AA increased, the adsorption amount per unit weight of $Pb^{2+}$ and $Cu^{2+}$ decreased. The MC-g-AA showed the high $Pb^{2+}$ and $Cu^{2+}$ adsorption amount in the range pH $4{\sim}6$. Also all of $Pb^{2+}$ and $Cu^{2+}$ ions reached in adsorption equilibrium in neighborhood 4 hours. The adsorption of heavy metals described by Freundlich isotherm, it was determined the value of l/n of $Pb^{2+}$ and $Cu^{2+}$ that 0.4294 and 0.3453, respectively.