可变误差多面体法同时测定镧及其它轻稀土含量

报导了以化学性质极其相似的La、Ce、Pr、Nd、Sm为分析对象, 采用五个已知组成的标样, 通过全选主元的Gauss消去法求得单组分的吸光常数。据此再用可变误差多面体法求解样品中各组分的浓度, 实践证明, 此法不仅减小了实验误差和手工计算时间,而且考虑了组分间的相互作用, 能获得比较准确的结果, 可变误差多面体法也是解决这类问题更为合适的方法。     

稀土元素的电分析化学研究 IX:铽-8-羟基喹啉——-高氯酸钠的极谱配合附波

In this paper the polarographic behavior of terbium-oxine(Ox)- sodium perchlorate system has been studied. In the solution of NaClO4, Ox has a well defined single-sweep polarographic wave P1. After the addition of Tb3+ a new wave P2 appears at more negative potential. A linear calibration curve of the decrease of P1 is obtained in Tb3+ concentration range from 1.0X10-6M to 1.0X10-5M under the optimun conditions of pH4.0-4.5, 0.1M NaClO4-8X10-5M Ox. The wave height of P2 increases linearly with Tb3+ concentration from 3.0X10-6M to 3.0X10-5M in 0.1M NaClO4-2.0X10-4M Ox. It has been shown by applying a number of polarographic techniques that the wave is an adsorptive complex wave. We proposed the reduction processes of the complex and determined the dissocation constants of Ox.     

烯土硝酸盐冠醚配合物Y(NO3)3 3H2O-B15C5-CH3CN三元体系18`C时溶解度的研究

A semimicro method has been used to study the solubilities of the ternary system, Y(NO3)3.3H2O-B15C5-CH3CN, at 18C. The results indicated that there is only one complex formed in this system. The stable complex has been isolated and its composition was determined by chemical analysis to be Y(NO3)3.B15C5.3H2O and the dehydration behavior of the complex was studied using DTA and TG methods.     

氧在稀土酞菁上的电化学还原

过渡金属大环配合物(例如酞菁和卟啉)对氧的电化学还原具有很高的催化活性,因而是目前电化学最活跃的研究领域之一.关于氧在过渡金属大环配合物上电化学还原机理,一般认为与过渡金属的价态变化有关.近年来,由于稀土双酞菁具有电致变色(electrochromic)的特性,引起了人们极大的兴趣,并对它们的电化学行为进行了一系列的研究,但关于它们对氧的电化学还原作用却未见报道.我们利用循环伏安法研究了某些稀土单酞菁和双酞菁对氧的电化学还原的影响,并提出了氧的电化学还原的反应历程.     

稀土与双偶氮变色酸反应系列的动力学和机理特征

本文在前报基础上, 对稀土与双偶氮变色酸配合物反应选用了一系列体系进行了较系统的动力学研究, 实验获得速度方程的通式为:r=K-[RE(H2O)m3+m][H6R]β[H3O+]-1β=1或2。实验活化能分别处在40-70kj,mol之间, 根据速率方程所确定的速控步骤过渡态的组成, 参照Eign-Tamm机理, 它们可能遵循两种不同机理, 一种是配合物失水作为速控步骤, 一种是质子转移作为速控步骤, 动力学处理导出的方程与经验速率方程获得满意的吻合。     

基于多个小孔径基阵的水下目标宽带波达方位估计方法

本文将多小孔径基阵应用于声纳浮标阵对可疑海区进行快速搜索的研究中,提出了一种基于多个小孔径子阵的宽带目标方位估计方法.该方法采用一种新颖的降秩估计器的信号模型,对多个小孔径子阵的输出信息进行综合处理,然后使用近似意义上的降秩估计器对目标源进行方位估计.所建立的阵列模型中不需要包含有关小孔径子阵之间的任何位置信息,因此,有效地减小了因阵形估计带来的烦杂工作和估计误差对方位估计性能的影响.仿真结果表明,此方法提高了定向精度,给出了稳定的目标方位估计.     

稀土与L-脯氨酸配合物的合成、表征及晶体结构

本文合成了通式为Ln(L-Pro)3(H2O)3(ClO4)3(Ln=Pr、Nd、Er, L-Pro=L-脯氨酸)的固体配合物。元素分析、红外光谱、热分析对配合物进行了表征。培养了镨脯氨酸配合物的单晶, X射线四圆衍射确定了晶体的结构。晶体属于单斜晶系、空间群P2~1, a=0.9879(3), b=2.1883(4), c=1.3393(2)nm, β=91.23(2)°,v=2.895(1)nm^3, z=2。晶体中每一个镨原子与来自6个L-脯氨酸羧基上的6个氧原子和2个结晶水分子键合, 形成了一个八配位的稍有畸变的三角十二面体。每一个L-脯氨酸分子以羧基双齿方式与两个镨离子配位, 形成了一个无限长的链状结构。     

LaOX-Pr^3^+(X=Cl, Br)体系的荧光特性及其配位场理论解析

LaOX-Pr^3^+(X=Cl,Br)体系在室温和液氮温度下均只观察到^3P~0能级的发射,其原因在于Pr^3^+离子的4f5d激发态具有较高能量(>37kK),且^3P~2,^3P~1向^3P~0存在有效的电子驰豫;本文基于DSCPCF配位场模型的计算结果,对该体系的发射光谱和激发光谱进行了理论归属,实测峰位与计算值较好吻合。     

Simultaneous acquisition of phosphocreatine and inorganic phosphate images for Pi:PCr ratio mapping using a RARE sequence with chemically selective interleaving

The ratio of inorganic phosphate to phosphocreatine (Pi:PCr) is a validated marker of mitochondrial function in human muscle. The magnetic resonance imaging rapid acquisition with relaxation enhancement (RARE) pulse sequence can acquire phosphorus-31 (³¹P) images with higher spatial and temporal resolution than traditional spectroscopic methods, which can then be used to create Pi:PCr ratio maps of muscle regions. While the ³¹P RARE method produces images that reflect the content of the ³¹P metabolites, it has been limited to producing an image of only one chemical shift in a scan. This increases the scan time required to acquire images of multiple chemical shifts as well as the likelihood of generating inaccurate Pi:PCr maps due to gross motion. This work is a preliminary study to demonstrate the feasibility of acquiring Pi and PCr images in a single scan by interleaving Pi and PCr chemical shift acquisitions using a chemically selective radiofrequency excitation pulse. The chemical selectivity of the excitation pulse evaluated and the Pi:PCr maps generated using the interleaved Pi and PCr acquisition method with the subject at rest and during exercise are compared to those generated using separate Pi and PCr acquisition scans. A paired t test indicated that the resulting Pi:PCr ratios for the exercised forearm muscle regions were not significantly different between the separate Pi and PCr acquisition method (3.18±1.53) (mean±standard deviation) and the interleaved acquisition method (3.41±1.66). This work demonstrates the feasibility of creating Pi:PCr ratio maps in human muscle with Pi and PCr images acquired simultaneously by interleaving between the Pi and PCr resonances in a single scan.     

稀土与邻香兰素二胺类双Schiff碱配合物合成及其性质的研究

在非水体系中首次合成了硝酸稀土(III)的邻香兰素(2-羟基-3-甲氧基苯甲醛)与乙二胺(L^1)、联苯胺(L^2)、邻苯二胺(L^3)和间苯二胺(L^4)的双Schiff碱配合物(1-8)。通过测定红外光谱、摩尔电导、X射线衍射和X射线光电子能谱推断了配合物的结构和键合情况,配合物的中心金属离子与配体中的二个氮原子、二个氧原子和二个硝酸根中的四个氧原子配位,其配位数为8。通过热重及差热分析发现配合物在低于230℃时很稳定,对于同一配体与不同中心金属离子形成的配合物来说,其热稳定性随稀土离子半径的减小而降低。在77K时测试了铕配合物的激发光谱和荧光光谱,观察到Eu^3^+的特征发射峰。