• Journal of the Korean Magnetics Society
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• v.6 no.5
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• pp.323-328
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• 1996

NiFe($60\;{\AA}$)/Cu($60\;{\AA}$)/Co($30\;{\AA}$) trilayers were formed on the $4^{\circ}$ tilt-cut Si(111) substrate by rf magnetron sputtering method. With a Cu($50\;{\AA}$) underlayer, NiFe($60\;{\AA}$)/Cu($60\;{\AA}$)/Co($30\;{\AA}$) trilayers developed in-plane magnebc anisotropy and in-plane perpendicular alignment of easy axes in two magnetic components of NiFe($60\;{\AA}$)/Cu($60\;{\AA}$)/Co($30\;{\AA}$) trilayers has been found. The easy axis of Co layer consisbng of NiFe($60\;{\AA}$)/Cu($60\;{\AA}$)/Co($30\;{\AA}$) trilayers turned out to be along $4^{\circ}$ tilt Si <112> direcbon and that of NiFe layer along Si <110> direction. [NiFe($60\;{\AA}$)/Cu($60\;{\AA}$)/Co($30\;{\AA}$)]/Cu($50\;{\AA}$)/Si(111, $4^{\circ}$ tiIt-cut) trilayers showed about 2.2 % MR ratio at room temperature and large plateau in MR curves, which are more improved MR characteristics than those in [NiFe($60\;{\AA}$)/Cu($60\;{\AA}$)/Co($30\;{\AA}$)]/Cu($50\;{\AA}$)/glass trilayers with no appreciable magnetic anisotropy.

• 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.

• Korean Journal of Materials Research
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• v.29 no.6
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• pp.392-397
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• 2019

A cold roll-bonding process is applied to fabricate an AA6061/AA5052/AA6061 three-layer clad sheet. Two AA6061 and one AA5052 sheets of 2 mm thickness, 40 mm width, and 300 mm length are stacked, with the AA5052 sheet located in the center. After surface treatment such as degreasing and wire brushing, sample is reduced to a thickness of 1.5 mm by multi-pass cold rolling. The rolling is performed at ambient temperature without lubricant using a 2-high mill with a roll diameter of 400 mm at rolling speed of 6.0 m/sec. The roll bonded AA6061/AA5052/AA6061 complex sheet is then hardened by natural aging(T4) and artificial aging(T6) treatments. The microstructures of the as-roll bonded and age-hardened Al complex sheets are revealed by optical microscopy; the mechanical properties are investigated by tensile testing and hardness testing. After rolling, the roll-bonded AA6061/AA5052/AA6061 sheets show a typical deformation structure in which grains are elongated in the rolling direction. However, after T4 and T6 aging treatment, there is a recrystallization structure consisting of coarse equiaxed grains in both AA5052 and AA6061 sheets. The as roll-bonded specimen shows a sandwich structure in which an AA5052 sheet is inserted into two AA6061 sheets with higher hardness. However, after T4 and T6 aging treatment, there is a different sandwich structure in which the hardness of the upper and lower layers of the AA6061 sheets is higher than that of the center of the AA5052 sheet. The strength values of the T4 and T6 age-treated specimens are found to increase by 1.3 and 1.4 times, respectively, compared to that value of the starting material.

• Korean Journal of Materials Research
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• v.32 no.3
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• pp.161-167
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• 2022

A cold roll-bonding process is applied to fabricate an AA6061/AA5052/AA6061/AA5052 layered sheet. Two AA6061 and one AA5052 sheets of 2mm thickness, 40mm width and 300mm length are alternately stacked, then reduced to a thickness of 2.0 mm by multi-pass cold rolling after surface treatment such as degreasing and wire brushing. The rolling is performed at ambient temperature without lubricant using a 2-high mill with a roll diameter of 400 mm at a rolling speed of 6.0 m/sec. The roll-bonded AA6061/AA5052/AA6061/AA5052 layered sheet is then hardened by natural aging (T4) and artificial aging (T6) treatments. The microstructure of the as-roll bonded and the age-hardened Al sheets was revealed by SEM observation; the mechanical properties were investigated by tensile testing and hardness testing. After T4 and T6 aging treatment, the specimens had a recrystallization structure consisting of coarse equiaxed grains in both AA5052 and AA6061 regions. The as-roll-bonded specimen showed a clad structure in which the hardness of AA5052 regions was higher than that of AA6061 regions. However, after T4 and T6 aging treatment, specimens exhibited different structures, with hardness of AA6061 regions higher than that of AA5052 regions. Strengths of T6 and T4 age-treated specimens were found to increase by 1.55 and 1.36 times, respectively, compared to the value of the starting material.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.138-139
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• 2003

Sandwich sheet samples comprising AA1050/AA1050/AA1050, AA3003/AA1050/AA3003, AA3003 AA3003 AA3003. AA1050/AA3003/AA1050, SUS430/AA3003/SUS430, AA3003/SUS430/AA3003 and SUS430/SUS430/SUS430 were cold rolled in order to clarify the evolution of strain states md textures in the sandwich samples. To investigate the effect of stacking sequences of the samples on strain and texture, the relative contribution of each layer to the total reduction was measured and textures of the mid-layer sheet of sandwich samples were determined.

• Korean Journal of Materials Research
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• v.26 no.7
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• pp.388-392
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• 2016

A cold roll-bonding process was applied to fabricate an AA1050/AA6061/AA1050 laminate complex sheet. Two AA1050 and one AA6061 sheets of 2 mm thickness, 40 mm width and 300 mm length were stacked up after surface treatment that included degreasing and wire brushing; material was then reduced to a thickness of 3 mm by one-pass cold rolling. The laminate sheet bonded by the rolling was further reduced to 1.2 mm in thickness by conventional rolling. The rolling was performed at ambient temperature without lubricant using a 2-high mill with a roll diameter of 210 mm. The rolling speed was 5.0 m/sec. The AA1050/AA6061/AA1050 laminate complex sheet fabricated by roll bonding was then hardened by natural aging T4) and artificial aging (T6) treatments. The microstructures of the as-roll bonded and the age hardened Al complex sheets were revealed by optical microscope observation; the mechanical properties were investigated by tensile testing and hardness testing. The strength of the as-roll bonded complex sheet was found to increase by 2.9 times compared to that value of the starting material. In addition, the hardness of the complex sheets increased with cold rolling for AA1050 and age-hardening treatment for AA6061, respectively. After heat treatment, both AA1050 and AA6061 showed typical recrystallization structures in which the grains were equiaxed; however, the grain size was smaller in AA6061 than in AA1050.

• 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.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.75-82
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• 2011

Five different composition UV-cured poly(urethane acrylate-co-acrylic acid) (PU-co-AA) films have been prepared by reacting isophorone diisocyanate(IPDI), polycaprolactone triol(PCLT), 2-hydroxyethyl acrylate(HEA), and different weight ratio trimethylolpropane triacrylate(TMPTA) and acrylic acid(AA) as diluents, and characterized using a Fourier transform infrared spectroscopy(FT-IR). The adhesion properties onto the stainless steel, morphology, mechanical hardness, and electrical property of UV-cured PU-co-AA films were investigated as a function of acrylic acid(AA) content. All the PU-co-AA films are structure-less and the molecular ordering and packing density decreased with increasing content of AA due to the flexible structure and -COOH side chains in AA. The crosscut test showed that PU-co-AA films without AA and with low content of AA showed 0% adhesion(0B) and the adhesion of PU-co-AA films in the range of 40-50% AA increased dramatically as the content of AA increases. The pull-off measurements showed that the adhesion force of PU-co-AA films to stainless steel substrate varied from 6 to 31 kgf /$cm^2$ and increased linearly with increasing AA content. The mechanical hardness also decreased as the content of AA increases. This may come from relatively linear and flexible structure in AA and low crystallinity in PU-co-AA films with higher content of AA. The higher AA-containing PU-co-AA films showed higher dielectric constant due to the increase of polarization by introducing AA monomer. In conclusion, the physical properties of UV-cured PU-co-AA films are strongly dependent upon the content of AA and the incorporation of AA in polyurethane acrylate is very useful way to increase the adhesion strength of UV-curable polymers on the stainless steel substrate.

• Korean Journal of Materials Research
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• v.33 no.12
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• pp.565-571
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• 2023

AA1050/AA6061/AA1050 layered sheet was fabricated by cold roll-bonding process and subsequently T4 and T6 aging-treated. Two commercial AA1050 sheets of 1 mm thickness and one AA6061 sheet of 2 mm thickness were stacked up so that an AA6061 sheet was located between two AA1050 sheets. After surface treatments such as degreasing and wire brushing, they were then roll-bonded to a thickness of 2 mm by cold rolling. The roll-bonded Al sheets were then processed by natural aging (T4) and artificial aging (T6) treatments. The as roll-bonded Al sheets showed a typical deformation structure, where the grains are elongated in the rolling direction. However, after the T4 and T6 aging treatments, the Al sheets had a recrystallized structure consisting of coarse grains in both the AA5052 and AA6061 regions with different grain sizes in each. In addition, the sheets showed an inhomogeneous hardness distribution in the thickness direction, with higher hardness in AA6061 than in AA1050 after the T4 and T6 age treatments. The tensile strength of the T6-treated specimen was higher than that of the T4-treated one. However, the strength-ductility balance was much better in the T4-treated specimen than the T6-treated one. The tensile properties of the Al sheets fabricated in the present study were compared with those in a previous study.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.4
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• pp.508-514
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• 2010

This study was conducted to evaluate the effects of dietary arachidonic acid (AA, 20:4n-6) levels on growth performance and body composition in juvenile eel, Anguilla japonica. Six semi-purified experimental diets were formulated to be isonitrogenous and iso-caloric containing 55.0% crude protein and 15% crude lipid (18.3 kJ of available energy $g^{-1}$). Six different levels of AA were added to the basal diet, with 0, 0.2, 0.4, 0.6, 0.8 or 1.2% on a dry matter (DM) basis, respectively ($AA_{0.07},\;AA_{0.22},\;AA_{0.43},\;AA_{0.57},\;AA_{0.78}\;or\;AA_{1.23}$). After a conditioning period, fish initially averaging 27${\pm}$0.5 g (mean${\pm}$SD) were randomly distributed into each aquarium as triplicate groups of 20 fish each. One of six experimental diets was fed on a DM basis to fish in three randomly selected aquaria at a rate of 2-3% of total body weight twice a day. At the end of the 12-week feeding trial, weight gain (WG) and feed efficiency (FE) of fish fed $AA_{0.78}$ and $AA_{1.23}$ diets were significantly higher than of fish fed $AA_{0.07},\;AA_{0.22},\;AA_{0.43}$ diets (p<0.05). Specific growth rate (SGR) of fish fed the $AA_{0.78}$ diet was significantly higher than of fish fed $AA_{0.07},\;AA_{0.22},\;AA_{0.43}$ diets (p<0.05). However, there were no significant differences in WG, SGR and FE among fish fed $AA_{0.57},\;AA_{0.78}\;or\;AA_{1.23}$ diets (p>0.05). Whole body AA deposition of fish fed the $AA_{1.23}$ diet was significantly higher than for the other diets (p<0.05). Broken-line model analysis on the basis of WG and SGR indicated that the dietary AA requirement could be greater than 0.69% but less than 0.71% of the diet in juvenile eel. The growth-promoting activity of AA observed in the present study provides strong support for the contention that dietary AA is essential for juvenile eel.