镧系金属一氢化物有效芯势研究

采用Cundari和Stevens等推导的有效芯势对镧系金属一氢化物进行了理论计算，以探讨镧系金属元素与氢的相互作用。结果表明所有镧系金属一氢化物基态时理论上是稳定的，最稳定的是SmH,最不稳定的是DyH;键长计算结果显示，基态时镧系金属一招兵买马花物有独立王国 收缩现象发生；红外振动频率理论计算值与实验结果一致；成键轨道中，金属原子轨道的贡献主要是s轨道和d轨道：从CeH至ErH(GdH)例外）随着外层电子的增加s轨道成分逐渐增大d轨道成分逐渐减小；从TmH和LuH（包括GdH)，成键轨道中金属原子轨道的贡献主要是d轨道，约为90％；约大多数镧系金属一氧化物的成键轨道中金属原子轨道f成分小于1％。     

Extraction-ability and -selectivity of tetra-aza-crown ethers for transition metal cations

In order to investigate the relative effects of the differences between the structures and lipophilicities of 1, 10-dioxa-4, 7, 13, 16-tetra-azacyclo-octadecane (TA-18-crown-6) and the tetrabenzyl derivative of 1,10-dioxa-4, 7, 13, 16-tetra-azacyclo-octadecane (TBTA-18-crown-6) on their extraction-abilities and -selectivities for transition metal cations, constants of the overall extraction (logK _ex) of 1:1 (M:L) complexes, the distribution (K _D) for two diluents (CH₂Cl₂ and CHCl₃) with different dielectric constants have been determined at 25 ± 0.1 °C. The magnitude of logK _ex is largely determined by that of K _D. The equilibrium constants of TA-18-crown-6 have been compared with those of TBTA-18-crown-6. It is found that:(i) logK _ex sequences of TA-18-crown-6 and TBTA-18-crown-6 for transition metals in CH₂Cl₂ lie in order: Fe³⁺ > Cu²⁺ > Mn²⁺ > Co²⁺ > Cd²⁺ > Ni²⁺ > Zn²⁺ and Fe³⁺ > Cu²⁺ > Co²⁺ > Mn²⁺ > Ni²⁺ > Cd²⁺ > Zn²⁺ respectively; (ii) the stability sequences of two types of tetra-aza-crown ethers with the transition metal cations in CHCl₃ are the same as follows: Fe³⁺ > Ni²⁺ > Cu²⁺ > Co²⁺ > Zn²⁺ > Cd²⁺ > Mn²⁺, and (iii) unusual selectivities are observed for transition metal-tetra-aza-crowns, e.g. the high Fe³⁺/M ⁿ⁺ selectivity factors (S_f) of TA-18-crown-6, except for the competitive-extractions for the special case in CHCl₃ of TBTA-18-crown-6, it was found that the Mn²⁺/M ⁿ⁺ values were relatively higher according to the other transition metal cations. A systematic sequence in these two types of solvents is not found for a given transition metal cation in terms of the variation of selectivity with the tetra-aza-crown ethers. The results provide alternatives for the rational design of other specific ligands on the transition metal cations.     

Internet中的物理资源

对Internet中的物理资源进行了较系统的介绍，主要内容有：综合物理网站、物理期刊网站和物理教学网站，其中重点介绍了美国和欧洲主要国家的物理网站和物理期刊网站，利用这些物理站点，可以方便的进行文献检索、物理会议查询，物理教学相关资料的查询和世界各大学物理系的查询；可以方便快捷的了解当今世界各国的物理教学学科研的最新进展，文中对各个物理站点的使用方法都一一做了详细的介绍，以方便读者使用。     

Symmetries of Itô and Stratonovich Dynamical Systems and Their Conserved Quantities

A new definition for the symmetries of Itô and Stratonovich dynamicalsystem is given. Determining systems of symmetries for Itô andStratonovich systems have been obtained, and their relation has beendiscussed. It has been shown that some of the Lie point symmetries ofthe Fokker–Planck equation can be constructed using the symmetries ofItô dynamical systems. Conserved quantities can be found from thesymmetries of stochastic dynamical systems which do not arise from aHamiltonian. The results have been applied to an example.     

Eigenvalues of Two Parameter Polynomial Operator Pencils of Waveguide Type

The spectral structure of two parameter unbounded operator pencils of waveguide type is studied. Theorems on discreteness of the spectrum for a fixed parameter are proved. Variational principles for real eigenvalues in some parts of the root zones are established. In the case of n = 1 (quadratic pencils) domains containing the spectrum are described (see Fig. 1–3). Conditions in the definition of the pencils of waveguide type arise naturally from physical problems and each of them has a physical meaning. In particular a connection between the energetic stability condition and a perturbation problem for the coefficients is given.     

Über die Stromdichtepotentialkurven passivierbarer Metalle,am Beispiel des Eisens dargestellt

Zusammenfassung Es wurde an Hand des Zahlenmaterials meiner Arbeit »Über die Passivierung speziell des Eisens« a. a. O. gezeigt, da\ man unter BerÜcksichtigung der Zeiterscheinungen Stromspannungskurven fÜr die Passivierung des Eisens erhält, welche aus zwei ästen bestehen. Von diesen entspricht der eine dem Verhalten des aktiven, der andere dem Verhalten des passiven Metalles. Die frÜheren, ohne BerÜcksichtigung der Zeitverhältnisse von verschiedenen Forschern aufgestellten Kurven entsprechen mehr oder weniger Zufallswerten, geben das Verhalten eines Metalles, das aktiv und passiv auftreten kann, nicht vollständig wieder und sind als Grundlage theoretischer Diskussionen unzureichend.     

Retracted: Determination of scutellarin isomer,a predominant metabolite of scutellarin,in human plasma by HPLC/tandem mass spectrometry and its application to a pharmacokinetic study in Chinese healthy volunteers

Retraction: The following article from Biomedical Chromatography, “Determination of scutellarin isomer, a predominant metabolite of scutellarin, in human plasma by HPLC/tandem mass spectrometry and its application to the pharmacokinetic study in Chinese healthy volunteers” by Chun‐hua Xia, Yu‐qing Xiong, and Guang‐ji Wang, published online on 21 June 2007 in Wiley Interscience (www.interscience.wiley.com/journal/bmc), has been retracted at the authors' request.     

Buchbesprechungen

Ohne Zusammenfassung     

荧光法研究Ge-132对牛血清白蛋白Maillard反应的抑制作用

人体内氨基酸及蛋白质的非酶糖化反应(Maillard反应)与糖尿病及其并发症的关系已经引起广泛注意[1].有机锗化合物β-羧乙基锗倍半氧化物(Ge-132)具有预防糖尿病及调节糖代谢的作用[2].