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41.
Atsushi Takada Yu-Ichi Komizo Hidenori Terasaki Tomoyuki Yokota Kenji Oi Koichi Yasuda 《Welding International》2013,27(4):254-261
Inclusions contributing to acicular ferrite nucleation were investigated from a crystallographic point of view in low carbon low alloy steelweld metals. The samples from electro slag welding (ESW) and submerged arc welding (SAW) deposits with various cooling rates were prepared in this study. In those samples, intragranular acicular ferrite formation was observed from inclusions. The inclusions contributing to acicular ferrite formation were of multi-phase type consisting of amorphous phase, spinel type and MnS. They were surrounded by a Ti-enriched layer. It was confirmed by selected area diffraction patterns and energy-dispersive X-ray spectrometer analyses that the Ti-enriched layer was TiO. The acicular ferrite had a Baker–Nutting orientation relationship with the TiO layer on the inclusion surface. The misfit was 3.0% at the interface between the acicular ferrite and TiO. Therefore, it is considered that TiO on the inclusion surface contributes to the heterogeneous nucleation of acicular ferrite by small lattice misfit. However, themorphologies of ferrite growth which nucleated from inclusions were different in both samples. Whereas the growth of ferrites nucleated from TiO was enough in ESW, the size of nucleated ferrite in SAW was a few hundred millimetres in size. In the early stage of nucleation from TiO, ferrite had small deviation from Kurdjumov–Sachs orientation relationship (K–S relationship) in both ESW and SAW. However, there was a difference in the growth stage of ferrite. The ferrite orientations were gradually changed to fit to the K–S relationship in ESW. On the other hand, the nucleated ferrite in SAW stopped growing and the newly nucleated ferrite which had K–S relationship prior to austenite was formed adjacently because of large super cooling due to small heat input. 相似文献
42.
Randeep Rakwal Ganesh Kumar Agrawal Junko Shibato Tetsuji Imanaka Satoshi Fukutani Shigeru Tamogami Satoru Endo Sarata Kumar Sahoo Yoshinori Masuo Shinzo Kimura 《International journal of molecular sciences》2009,10(3):1215-1225
We report molecular changes in leaves of rice plants (Oryza sativa L. - reference crop plant and grass model) exposed to ultra low-dose ionizing radiation, first using contaminated soil from the exclusion zone around Chernobyl reactor site. Results revealed induction of stress-related marker genes (Northern blot) and secondary metabolites (LC-MS/MS) in irradiated leaf segments over appropriate control. Second, employing the same in vitro model system, we replicated results of the first experiment using in-house fabricated sources of ultra low-dose gamma (γ) rays and selected marker genes by RT-PCR. Results suggest the usefulness of the rice model in studying ultra low-dose radiation response/s. 相似文献
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Supermicroporous Niobium Oxide as an Acid Catalyst 总被引:1,自引:0,他引:1
Mayako Hiyoshi Byongjin Lee Daling Lu Michikazu Hara Junko N. Kondo Kazunari Domen 《Catalysis Letters》2004,98(4):181-186
Supermicroporous (1.5–2.5 nm pore diameter) niobium oxide is synthesized using a nonionic block copolymer as a structural directing reagent, which is removed by water washing after aging. The oxide contains water in the bulk material in the form of a water-rich niobium oxide. The supermicroporous niobium oxide is applicable for various acid-catalyzed reactions. 相似文献
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Rapid solidification magnesium alloy powders produced by spinning water atomization process were hot extruded into rectangular bars, from which tensile and compression samples have been cut at 0°, 45° and 90° angles from the extrusion direction to study their anisotropy. Electron back-scattered diffraction analysis has been used to investigate the texture evolution during the extrusion process. Texture parameters like the Schmid factor and the intensity of (0 0 0 1) basal plane in the pole figure have been evaluated and correlated to the mechanical properties. Results have shown that the extruded rods exhibited high strength and relatively less anisotropy compared to other previously reported values for wrought magnesium alloys. Tensile and compression yield stresses have shown very similar values to each other at all loading directions. This limited anisotropy could be linked to both the fine grained and inter-metallic-compound-dispersed microstructure of the extruded alloys. Dynamic recrystallization behavior during hot extrusion has also been investigated in the present study. 相似文献
47.
Magnesium (Mg) composite reinforced with carbon nanotubes (CNTs) having superior mechanical properties was fabricated using both pure Mg and AZ61 Mg alloy matrix in this study. The composites were produced via powder metallurgy route containing wet process using isopropyl alcohol (IPA) based zwitterionic surfactant solution with unbundled CNTs. The produced composites were evaluated with tensile test and Vickers hardness test and analyzed by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM) equipped with energy dispersive spectroscopy (EDS) and electron back scattered diffraction (EBSD). As a result, only with AZ61 Mg alloy matrix, tensile strength of the composite was improved. In situ formed Al2MgC2 compounds at the interface between Mg matrix and CNTs effectively reinforced the interfacial bonding and enabled tensile loading transfer from the Mg matrix to nanotubes. Furthermore, it was clarified that the microstructures and grain orientations of the composite matrix were not significantly influenced by CNT addition. 相似文献
48.
Kawahara J Tanaka S Tanaka C Aoki Y Yonemoto J 《The Science of the total environment》2011,409(16):3073-3077
The activity of 5- to 6-year-old Japanese children (n = 29) was monitored for 3 consecutive days, including one weekend day, using an ActivTracer tri-axial accelerometer. The daily inhalation rate and time spent in sedentary, light, or moderate to vigorous levels of physical activity (MVPA) were estimated from the accelerometer measurements based on previously developed regression equations. The 3-day mean daily inhalation rate (STPD) was estimated at 8.3 ± 1.4 m3 day−1 in 10 subjects who completed 3 days of monitoring. The time spent in sedentary, light, or MVPA each day was 320, 415, and 81 min day−1, respectively. Analysis of between-day reliability indicated that 3 days of monitoring with the ActivTracer tri-axial accelerometer provided an acceptable estimate of daily inhalation rate (intra-class correlation coefficient [ICC] = 0.892), but low to moderate reliability for the time spent in different levels of activities (ICC = 0.43 to 0.58). We observed a significant difference in the daily inhalation rate between weekdays and the weekend day, possibly due to differences in time spent in MVPA. This finding suggests that a weekend day should be included to obtain more reliable estimates of daily inhalation rate using an accelerometer. 相似文献
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