Nabil S. Youssef
,
K.H.Hegab
材料科学技术（英文）
Some transition metal chelates of two ligands L1 and L2 were prepared and characterized by elemental analysis. The IR and 1H NMR spectra of several chelates of two ligands L1 and L2 showed the involvement of the azo group in chelation with the transition metal ions, in most of the studied chelates, and that the two ligands L1 and L2 showed the involvement of the azo group in chelation with the transition metal ions, in most of the studied chelates, and that the two ligands L1 and L2 were coordinated either in the enol or the keto form. IR spetra also showed that Fe(III)-, Ni(II)-, Mn(II)-, VO(II)-L1 and Cu(II)-L2 chelates behaved in a bidentate manner, in contrast with the two (1:1) M:L cobalt chelates with the two ligands are tridentate. TG analysis indicated the presence of three to twelve water molecules of hydration eliminated on heating up to 150°C and one or two coordinated water molecules removed at 150-180°C. The octahedral structure is proposed for all the chelates, except Cu(II)-L2 and Ni(II)-L1 chelates which have square planar geometry, based on their electronic spectra.
关键词:
Applied Physics Letters
Amorphous Ge1-xSx(x=0.61, 0.67, and 0.72) semiconductor alloys have been found formed by ball milling of powder mixtures of elemental Ge and S. The amorphization process and the ball-milled products have been investigated by x-ray diffraction, transmission electron microscopy, and Raman scattering. The results show that amorphous Ge-S alloys may form in a self-heating reaction, driven by the large heat of formation of amorphous and/or liquid Ge-S alloys. The structure of mechanically alloyed amorphous Ge-S alloys is similar to but not exactly identical with that of rapidly cooled amorphous Ge-S alloys. The amorphization transition mechanism reported is believed to be suitable for preparing other amorphous semiconductor alloys with similar thermodynamic conditions.
关键词:
magnetic-properties;ni-zr;amorphization;powders;transition;interdiffusion;germanium;systems;glasses;metals
Ting DU Longmei WANG Yeming WU Yuqing ZHANG Aisheng LIU Central Iron and Steel Research Institute
,
Beijing
,
100081
,
China
材料科学技术（英文）
The temperature dependences of the equilibrium constants for the reactions RES_((S))=[RE]+[S]. (RE=Ce,La,Nd,Sm,Y),of the standard Gibbs energies for the RES formed and of the interaction coefficients between RE elements and S for the Fe-base,Ni-base and Cu-base solutions are sum- marized.
关键词:
thermodynamics
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null
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null
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null
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null
Applied Physics Letters
Transport in S(2) molecules sandwiched between Au electrodes is investigated with a combination of density functional theory and the non-equilibrium Green's function method. We consider four different configurations and find that their conductances are related to the details of the bonding geometry. When S(2) connects to pyramidal-shaped electrodes at the top site, the transmission is governed by a resonance and is strongly affected by the bias. In contrast, the transport of the remaining three configurations is through several closely spaced broad molecular orbitals, and the transmission coefficient is almost flat around the Fermi level. (C) 2012 American Institute of Physics. [doi:10.1063/1.3665614]
关键词:
conductance;molecule
孙新阁
,
霍立兴
,
张玉凤
腐蚀学报（英文）
采用楔形张开加载恒位移实验研究了X65管线钢在H2S溶液中的应力腐蚀开裂行为，并得出了X65管线钢母材、焊缝和热影响区的临界应力强度因子KISCC分别为55.7093 MPa•m 1/2、33.3189 MPa•m1/2和38.0711 MPa•m1/2；平台处的裂纹扩展速率da/dt分别为3.38×10－9m/s、3.5×10－9 m/s和3.5×10－9m/s.研究结果还表明，焊缝比母材具有更高的应力腐蚀敏感性.
关键词:
管线钢
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null
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null
