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51.
Corrosion and passivation behavior of Mg-Zn-Y-Al alloys prepared by cooling rate-controlled solidification 总被引:1,自引:0,他引:1
Michiaki Yamasaki Shogo IzumiYoshihito Kawamura Hiroki Habazaki 《Applied Surface Science》2011,257(19):8258-8267
Highly corrosion-resistant nanocrystalline Mg-Zn-Y-Al multi-phase alloys have been prepared by consolidation of rapidly solidified (RS) ribbons. The relation between corrosion behavior and microstructure evolution of Mg-Zn-Y-Al alloys with a long period stacking ordered phase has been investigated. In order to clarify the influence of rapid solidification on the occurrence of localized corrosion such as filiform corrosion, several Mg96.75Zn0.75Y2Al0.5 (at.%) alloys with different cooling rates are fabricated by the gravity casting, copper mould injection casting and melt-spinning techniques and their corrosion behavior and microstructures are examined by the salt water immersion test, electrochemical measurements, GDOES, XRD, SEM and TEM. To clarify the effect of aluminium addition on the improvement in corrosion resistance of the alloys, several Mg97.25−xZn0.75Y2Alx alloys with different aluminium contents are fabricated by consolidating RS ribbons and the formation of corroded films on the Mg-Zn-Y-Al alloys have been investigated. Rapid solidification brings about the grain refinement and an increase in the solid solubility of zinc, yttrium and aluminium into the magnesium matrix, enhancing microstructural and electrochemical homogeneity, which in turn enhanced corrosion resistance. The addition of aluminium to magnesium can modify the structure and chemical composition of surface films and improves the resistance to local breakdown of the films. 相似文献
52.
Magnetite particles were synthesized through a process including dissolution of Fe(OH)2 and precipitation of an oxidized phase in aqueous solution. The Fe3+ ion was added at the beginning of the synthesis to accelerate the formation of magnetite, control the particle size and improve the monodispersibility. It was found that the addition of Fe3+ ion affected the nucleation and the formation of magnetite particles significantly. Magnetite nanoparticles with small particle size and narrow size distribution were obtained. Furthermore, high magnetic properties were obtained in small particle size. The particle size and magnetic properties increased through the increase of Fe2+/Fe3+ ratio. 相似文献
53.
We synthesized the DNA oligonucleotide containing a new cross-linkable 4-amino-2-oxo-6-vinyltriazine (AOVT) nucleobase analogue (Et-AOVT) and evaluated these properties. Our results of the cross-link assay and thermal denaturing assay of duplexes containing AOVT demonstrated that the additional aza of AOVT has an impact on the duplex stability and crosslink properties. Our data suggests that the additional 5-aza of AOVT is involved in the hydrogen bonding with the complementary guanine, and this hydrogen bonding system successfully flipped the reactive vinyl group out to the major groove of the duplex demonstrating a new paradigm of a “cross-linkable duplex”. 相似文献
54.
Masatoshi Enomoto 《Advances in Mathematics》2006,201(2):263-317
We study the relative position of several subspaces in a separable infinite-dimensional Hilbert space. In finite-dimensional case, Gelfand and Ponomarev gave a complete classification of indecomposable systems of four subspaces. We construct exotic examples of indecomposable systems of four subspaces in infinite-dimensional Hilbert spaces. We extend their Coxeter functors and defect using Fredholm index. The relative position of subspaces has close connections with strongly irreducible operators and transitive lattices. There exists a relation between the defect and the Jones index in a type II1 factor setting. 相似文献
55.
Kazuyuki Enomoto 《Geometriae Dedicata》1997,65(2):193-201
The total squared curvature of a closed plane curve is minimized by a covering of a circle, if the rotation number of the curve is not zero. We measure the closeness of a closed plane curve to a circle by the difference of its total squared curvature from the minimum. A similar result is obtained for a simple closed curve in the 2-sphere. 相似文献
56.
Frontispiece: Entropy‐Driven 1,2‐Type Friedel–Crafts Reaction of Phenols with N‐tert‐Butoxycarbonyl Aldimines
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57.
Masaya Enomoto Noriyuki KidaNorimichi Kojima Isao WatanabeTakao Suzuki Yasuyuki Ishii 《Polyhedron》2011,30(18):3137-3139
We have investigated the magnetic properties of iron mixed-valence complexes, (n-CnH2n+1)4N[FeIIFeIII(dto)3] (dto = C2O2S2, n = 3, 5), in which not only a ferromagnetic transition but also a novel charge transfer phase transition (CTPT) take place [1]. This CTPT can be observed under ambient pressure for n = 3, while it appears abruptly above 0.5 GPa for n = 5 [2]. Recently, we have measured the muon spin relaxation (μSR) for the CTPT of n = 3, which revealed the dynamical process of electron-transfer between FeII and FeIII and its frequency was estimated at about 0.1 MHz [3]. To investigate the pressure induced CTPT for n = 5, we carried out the μSR measurement for n = 5 at 150 K between 0.30 and 0.64 GPa with the 4He gas-operated pressure system. The asymmetry of the muon spin relaxation for n = 5 with Cu-Be pressure cell was almost constant up to 0.55 GPa, while it rapidly decreased with increasing pressure above 0.60 GPa. This result shows that the applied pressure causes the spin fluctuation due to the CTPT, which induces the decrease of the asymmetry of muon spin relaxation. This experiment can correctly decide the phase transition pressure from the absence to the appearance of the CTPT for n = 5. 相似文献
58.
Otani M Taniguchi T Sakai A Seta J Kadoyama K Nakamura-Hirota T Matsuyama S Sano K Takano M 《Applied biochemistry and biotechnology》2011,164(6):804-818
We validated the novel PhosphoQUANTI SolidBlue Complex (PQSC) dye for the sensitive fluorescent detection of phosphorylated proteins in polyacrylamide- and two-dimensional gel electrophoresis (PAGE and 2DE, respectively). PQSC can detect as little as 15.6 ng of ß-casein, a pentaphosphorylated protein, and 61.3 ng of ovalbumin, a diphosphorylated protein. Fluorescence intensity correlates with the number of phosphorylated residues on the protein. To demonstrate the specificity of PQSC for phosphoproteins, enzymatically dephosphorylated lysates of Swiss 3T3 cells were separated in 2DE gels and stained by PQSC. The fluorescence signals in these gels were markedly reduced following dephosphorylation. When the phosphorylated proteins in Swiss 3T3 cell lysates were concentrated using a phosphoprotein enrichment column, the majority of phosphoproteins showed fluorescence signals in the pI 4–5 range. Finally, we performed phosphoproteome analysis to study differences in the protein phosphorylation profiles of proliferating and quiescent Swiss 3T3 cells. Over 135 discernible protein spots were detected, from which a selection of 15 spots were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF-MS). The PQSC staining procedure for phosphoprotein detection is simple, reversible, and fully compatible with MALDI TOF-MS. 相似文献
59.
Zaima N Goto-Inoue N Hayasaka T Enomoto H Setou M 《Analytical and bioanalytical chemistry》2011,400(7):1865-1871
It has become necessary to assess the authenticity of beef origin because of concerns regarding human health hazards. In this
study, we used a metabolomic approach involving matrix-assisted laser desorption/ionization imaging mass spectrometry to assess
the authenticity of beef origin. Highly accurate data were obtained for samples of extracted lipids from beef of different
origin; the samples were grouped according to their origin. The analysis of extracted lipids in this study ended within 10 min,
suggesting this approach can be used as a simple authenticity assessment before a definitive identification by isotope analysis. 相似文献
60.
The mammalian tongue is one of the most important organs during food uptake because it is helpful for mastication and swallowing.
In addition, taste receptors are present on the surface of the tongue. Lipids are the second most abundant biomolecules after
water in the tongue. Lipids such as phosphatidylcholine (PC), lysophosphatidylcholine (LPC) and sphingomyelin (SM) are considered
to play fundamental roles in the mediation of cell signaling. Imaging mass spectrometry (IMS) is powerful tool for determining
and visualizing the distribution of lipids across sections of dissected tissue. In this study, we identified and visualized
the PC, LPC, and SM species in a mouse tongue body section with matrix-assisted laser desorption/ionization (MALDI)-IMS. The
ion image constructed from the peaks revealed that docosahexaenoic acid (DHA)-containing PC, LPC, linoleic acid-containing
PC and SM (d18:1/16:0), and oleic acid-containing PC were mainly distributed in muscle, connective tissue, stratified epithelium,
and the peripheral nerve, respectively. Furthermore, the distribution of SM (d18:1/16:0) corresponded to the distribution
of nerve tissue relating to taste in the stratified epithelium. This study represents the first visualization of PC, LPC and
SM localization in the mouse tongue body. 相似文献