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八配位钇(Ⅲ)-反式-1,2-环己二胺四乙酸配合物NH4[Y(trans-CYDTA)(H2O)2]·4.5H2O的合成及分子结构 总被引:10,自引:0,他引:10
In this paper, the molecular and crystal structures of the NH4[Y(trans CYDTA)(H2O)2]·4.5 H2O(trans-CYDTA=trans 1,2-cyclohexanediaminetetraacetic acid) are reported. The crystal data are as follows: Triclinic system, P1space group,a=0.8599(6)nm,b=1.0021(7)nm,c=1.4370(9)nm,α =88.095(13)°,β =75.559(1)°,γ =88.344(12)°,V=1.1981(14)nm3,Z=2, M=708.68,Dc=1.570g· cm-3, μ =2.506mm-1 and F(000)=590. The final R1 and wR2 are 0.0571 and 0.1350 for 4205 [I >2.0σ (I)] unique reflections and 0.1007 and 0.1615 for all 4981 reflections, respectively. In the title complex, the anion [Y(trans-CYDTA)(H2O)2]- has an eight coordination structure with distorted square antiprism. The trans CYDTA which acts as a hexadentate ligand with four Oatoms and two Natoms and two H2O molecules directly coordinate to central metal Y(Ⅲ) ion. It can be known that the Y(Ⅲ) ion can form an eight coordinate compound with aminopolycarboxylic acid ligands in addition nine coordination structure. 相似文献
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张向东刘天伟李芳芳肖红陆雷 《原子核物理评论》2015,(S1):64-68
采用强流脉冲电子束对含有α+β两相的亚稳β钛合金进行了表面处理。处理使用的电子束加速电压为27 k V,脉冲次数分别为5,10和25次,脉冲持续时间为2μs。采用金相显微镜、扫描电子显微镜、电子背散射衍射和X射线衍射等技术对处理后的样品表面形貌和组织结构进行分析。结果表明,5次脉冲处理样品表面呈现波状特征,增加脉冲处理,样品表面变得较为平坦且出现了层片状特征;处理后样品表层α相逐渐消失,出现了应力诱发的α′′马氏体组织。 相似文献
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通过高温固相法合成了Dy3+,Tm3+单掺杂的四硼酸锌(ZnB4O7)磷光体,测定了室温下这2个磷光体经60Coγ-射线辐照后的三维热释光谱。从三维热释光谱可以观察到:这2个磷光体的主发光峰均位于218℃;ZnB4O7∶Tm3+磷光体的主热释光峰的发射波长为366、453、475、651和754 nm,ZnB4O7∶Dy3+磷光体的主热释光峰的发射波长为480、573、665和755 nm,分别为稀土离子Tm3+和Dy3+的特征跃迁发射。对于Tm3+掺杂的ZnB4O7磷光体,热释光发射强度较高,在辐射剂量学领域有潜在的应用。利用峰形法,评估了ZnB4O7∶Tm3+磷光体在218℃时发光峰的动力学参数,其陷阱深度E为1.64 eV,频率因子为3.42×1016s-1,遵循二级动力学。 相似文献
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We extend the hole confinement model of Edwards et al. to the problem of two kinds of complex magnetic sandwich structures. One is the magnetic sandwich covered on both sides by nonmagnetic films(case 1) and the other is that covered by magnetic films(case 2). The interlayer exchange coupling and the angular dependence of coupling energy in the two cases are investigated systematically. For case 1, our results show that the magnetic and outer nonmagnetic films influence significantly the oscillation behavior of exchange coupling and the appearance of noncollinear exchange coupling is very sensitive to the thickness of magnetic and outer nonmagnetic layers. Our results also show that the nonoscillatory component of the coupling generally varies with the thickness of magnetic(outer nonmagnetic) films and the results in the case where the thickness of both magnetic(outer nonmagnetic) films vary simultaneously are significantly different from that in the case where the thickness of one of the two magnetic(outer nonmagnetic) films is fixed while the other is varied, which is qualitatively in agreement with the experimental measurements. For case 2, the exponential dependence of exchange coupling on the thickness of the intermagnetic layer has been obtained, similar to the Parkin's experimental results for giant magnetoresistance. 相似文献
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泥岩三轴蠕变实验研究 总被引:1,自引:0,他引:1
采用MTS伺服刚性压力实验机对高家梁煤矿泥岩进行了三轴蠕变实验研究,获得了泥岩在不同应力条件下的蠕变变形规律。实验表明围压对泥岩微观缺陷的发展有一定的限制作用。随着围压的增加,泥岩的三轴抗压强度和弹性模量均有所增加。在围压一定时:衰减蠕变量随轴压的增大而增大;衰减蠕变率随偏应力的增加而增大;稳态蠕变率随偏应力的增大而增大。在偏应力一定时,稳态蠕变率随围压的增大而减小。当围压大于4MPa后,围压的限制作用将明显减小。随着围压继续增大,稳态蠕变率变化并不明显。根据获得的实验数据,用回归法求出了H-K模型蠕变方程的参数。结果表明H-K模型能较好地模拟实验结果。在实际工程中可通过支护增加围压以提高围岩屈服强度,也可根据实际工程中泥岩蠕变的变化趋势确定合理的二次支护时间,避免流变破坏的发生。 相似文献
10.
Huizhen Zhang 《中国物理 B》2021,30(11):113303-113303
Chirality is ubiquitous in natural world. Although with similar physical and chemical properties, chiral enantiomers could play different roles in biochemical processes. Discrimination of chiral enantiomers is extremely important in biochemical, analytical chemistry, and pharmaceutical industries. Conventional chiroptical spectroscopic methods are disadvantageous at a limited detection sensitivity because of the weak signals of natural chiral molecules. Recently, superchiral fields were proposed to effectively enhance the interaction between light and molecules, allowing for ultrasensitive chiral detection. Intensive theoretical and experimental works have been devoted to generation of superchiral fields based on artificial nanostructures and their application in ultrasensitive chiral sensing. In this review, we present a survey on these works. We begin with the introduction of chiral properties of electromagnetic fields. Then, the optical chirality enhancement and ultrasensitive chiral detection based on chiral and achiral nanostructures are discussed respectively. Finally, we give a short summary and a perspective for the future ultrasensitive chiral sensing. 相似文献