G.Y. Sha
金属学报(英文版)
An experimental-numerical method for measuring dynamic crack propagating veloc-ities under stress wave loading is established in this paper. The experiments of thethree-point bend specimen are done on the improved Hopkinson bar. Deflection ofloading point, dynamic load and instantaneous crack length ave measured, then crackpropagating velocities are calculated. Experiments on 40Cr steel show that the resultsgiven by this method have a good agreement with that obtained by the resistance frac-ture gage method. Therefore this method is feasible for measuring crack propagatingvelocities under high loading rate and will have wide application.
关键词:
stress wave loading
,
null
Journal of Superconductivity and Novel Magnetism
The local structure and the g factors (g(x), g(y), and g(z)) of the Cu(2+) site in Y(2)BaCuO(5) are theoretically studied using the perturbation formulas of the g factors for a 3d(9) ion in orthorhombically elongated octahedra. The orthorhombic field parameters in these formulas are determined from the superposition model and the local geometry of the system. From the calculations, the oxygen octahedron is found to undergo the local elongation Delta Z (approximate to 0.05 angstrom) along c-axis and the relative bond length variation Delta X (approximate to 0.1 angstrom) along a- and b-axes, respectively. The calculated g factors based on the above local structure are in good agreement with the experimental data. The relationships between the anisotropies of the g factors and the low symmetrical (orthorhombic) distortions of the Cu(2+) site in Y(2)BaCuO(5) are discussed.
关键词:
Crystal fields and spin Hamiltonians;Electron paramagnetic resonance;Cu(2+);Y(2)BaCuO(5);crystal
于萍
,
王亚权
腐蚀学报（英文）
研究了添加0.1mass%稀土Y的铸造K38G高温合金在1000℃的恒温氧化行为.结果表明,较之不含Y的合金，含Y铸态K38G合金的氧化速率显著降低； 氧化时形成双层的外氧化膜，表层为以Cr2O3和TiO.2为主的混合氧化物层，内层为连续的Al2O3层；没有内氧化和内氮化，没有氧化膜的剥落，加入稀土Y有效地提高了氧化膜的粘附性能.
关键词:
高温氧化
,
null
,
null
,
null
于萍
,
王亚权
腐蚀学报（英文）
doi:10.3969/j.issn.1002-6495.2007.03.010
研究了添加0.1 mass%稀土Y的铸造K38G高温合金在1000℃的恒温氧化行为.结果表明,较之不含Y的合金,含Y铸态K38G合金的氧化速率显著降低;氧化时形成双层的外氧化膜,表层为以Cr2O3和TiO2为主的混合氧化物层,内层为连续的Al2O3层;没有内氧化和内氮化,没有氧化膜的剥落,加入稀土Y有效地提高了氧化膜的粘附性能.
关键词:
高温氧化
,
K38G
,
高温合金
,
稀土元素
,
Y
于萍
,
王亚权
,
王文
腐蚀学报（英文）
对加入0.05mass%～0.5mass%稀土Y铸造的K38G高温合金800 ℃恒温的氧化行为进行了研究.结果表明,含Y铸态K38G合金的氧化动力学曲线偏离了抛物线规律，接近于立方规律；Y有效抑制了该合金的内氧化；当Y含量达0.5mass%时，该合金中析出富Y相，降低了其氧化抗力.
关键词:
高温氧化
,
null
,
null
Physica Status Solidi B-Basic Research
The perturbation formulas of EPR g factors g(\\) g(perpendicular to) and hyperfine structure constants A(\\) A(perpendicular to) for the trigonal octahedral 3d(7) cluster are derived considering not only the configuration interaction effect due to the admixture among ground and excited states, but also the covalency effect due to the admixture between the d electrons of the 3d(7) ion and the p electrons of ligands. In these formulas, the parameters related to both effects and the trigonal field parameters are estimated from the optical spectra and the structural parameters of the studied system. According to these formulas, the EPR parameters g(\\), g(perpendicular to), A(\\) and A(perpendicular to) for Co2+ in the octahedral sites of Y3Al5O12 and Y3Ga5O12 garnets are satisfactorily explained from the optical spectra and the structure data. The role of the covalency effect is discussed.
关键词:
superposition model;phase-transition;absorption;linbo3;ions
史小慧
,
王蕊欣
,
高保娇
,
雷彩萍
,
李艳华
高分子材料科学与工程
首先采用氯甲基化试剂1,4-二氯甲氧基丁烷对水杨羟肟酸(SHA)实施氯甲基化反应,制得氯甲基化水杨羟肟酸(CMSHA);然后以聚甲基丙烯酸羟乙酯(PHEMA)改性的硅胶微粒PHEMA/SiO2为载体,使其表面的醇羟基与CMSHA上的氯甲基基团发生亲向取代反应,制得水杨羟肟酸功能化的复合螯合吸附材料(SHA-PHEMA/SiO2).考察了取代反应的主要影响因素;并研究了SHA-PHEMA/SiO2对重金属离子的螯合性能.结果表明,CMSHA与PHEMA/SiO2之间的取代反应遵循单分子取代反应(SNl)的机理;较高温度下,强极性溶剂有利于反应的进行.SHA-PHEMA/SiO2对不同重金属离子表现出不同的螯合吸附能力,摩尔吸附容量的顺序为Cu2+＞ Zn2+ ＞Cd2+＞ Pb2+;SHA-PHEMA/SiO2对Cu2+离子的吸附动力学符合伪二级速率方程;其吸附行为同时遵循Freundlich和Langmuir模式.
关键词:
水杨羟肟酸
,
聚甲基丙烯酸羟乙酯
,
硅胶
,
亲核取代反应
,
螯合吸附
