The Isoelectric Point and the Points of Zero Charge of Fe-Al-Mg Hydrotalcite-like Compounds

The relation of the isoelectric point (IEP) and the point of zero net charge (PZNC) of the hydrotalcite-like compounds was discussed. It was found that the IEP does not equal to the PZNC and the IEP is higher than the PZNC. The structural positive charges existing in the HTlc,which cause the difference between the IEP and the PZNC. The effects of the structural positive charges of the HTlc on its IEP and PZNC are the same as the specific adsorption of metal cations.     

关于具有给定Sylow子群正规化子的有限群Ⅱ

本文在有限可解群中解决了：任意ｍ－秩≤２的子群闭的局部群系具有性质：“如果群Ｇ的非单位Ｓｙｌｏｗ子群的正规化子属于，则群Ｇ也属于的一个充分必要条件．     

横向放大率法确定复合光学系统的基点

介绍了应用测量横向放大率确定两薄透镜组成的复合光学系统基点的方法。由于采用线阵光电耦合器件（CCD）测量物经光学系统成像的横向放大率，提高了测量精度。     

一类求解线性约束非线性规划问题的可行方向法

Wilson,Han和Powell提出的序列二次规划方法(简称SQP方法)是求解非线性规划问题的一个著名方法,这种方法每次迭代的搜索方向是通过求解一个二次规划子问题得到的,本文受[1]启发,得到二次规划子问题的一个近似解,进而给出了一类求解线性约束非线性规划问题的可行方向法,在约束集合满足正则性的条件下,证明了该算法对五种常用线性搜索方法具有全局收敛性。     

Computations of critical groups and applications to asymptotically linear wave equation and beam equation

In this paper, by using the Morse index theory for strongly indefinite functionals developed in [Nonlinear Anal. TMA, in press], we compute precisely the critical groups at the origin and at infinity, respectively. The abstract theorems are used to study the existence (multiplicity) of nontrivial periodical solutions for asymptotically wave equation and beam equation with resonance both at infinity and at zero.     

Photoluminescence characteristics of ZnTiO3: Bi nanocrystals

The photoluminescence properties of the Bi³⁺ in sol-gel derived ZnTiO₃ nanocrystals have been investigated. An ultra-violet emission at 360 nm and a visible emission band at 506 nm have been observed, originating from two kinds of emission centers. The former is ascribed to the ³P₁-¹S₀ transition of Bi³⁺ and the latter to the recombination of the electrons with the photo-generated holes trapped in the zinc vacancies. In all cases the latter contribution is predominant.     

NOESY技术在地胆草倍半萜内酯化合物结构鉴定中的应用（I）

明确从地胆草中分离得到的两对牦牛儿内酯型的立体异构体即地胆草种内酯（scabertopin）、异地胆草种内酯（isoscabertopin）、异去氧地胆草内酯（isodeoxyelephantopin）和去氧地胆草内酯（deoxyelephantopin）的C-2相对构型；方法 NOESY技术，并结合这4个化合物的¹H NMR，¹³C NMR，HMQC谱；结果 两对立体异构体的NOESY谱有明显差异；结论 通过分析NOESY谱，找寻H-1相关信息，若发现H-1与H-8，H-9β和14-CH₃有NOE相关，可以判断化合物的C-2为α构型，若H-1与H-5，H-7，H-3α及H-9α之间有NOE相关，则化合物的C-2为β构型.     

Ionic conductivity of epitactic MBE-grown BaF2 films

We studied parallel conductivities of pure BaF₂ films with thicknesses ranging from 35 to 300 nm, epitaxially grown on Al₂O₃(0 1 2) substrates by molecular beam epitaxy technique. The overall conductivities of the films are found to increase with decreasing thickness. The detailed investigation of the overall conductance as a function of the thickness permits the deconvolution of bulk and boundary effects, the latter being attributed to distinct space charge effects in the interface between BaF₂ film and Al₂O₃ substrate. The (extrinsic) Debye length (λ) is estimated to be about 8 nm at T=593 K, which corresponds to an impurity content of 10¹⁸/cm³ (singly ionized dopant assumed). This is consistent with the fact that we observed a constant boundary contribution for all investigated films (film thickness >4λ). It is also consistent with the Debye length observed in a previous report on CaF₂/BaF₂ heterolayers fabricated by the same technique, in which the low temperature enhancement was also attributed to space charges in BaF₂ [Nature 408 (2000) 946]. Only at low temperatures (below 370 °C), the conductance seems to be influenced by strain effect.