-metrics, projective flatness and families of polarized abelian varieties

We compute the curvature of the -metric on the direct image of a family of Hermitian holomorphic vector bundles over a family of compact Kähler manifolds. As an application, we show that the -metric on the direct image of a family of ample line bundles over a family of abelian varieties and equipped with a family of canonical Hermitian metrics is always projectively flat. When the parameter space is a compact Kähler manifold, this leads to the poly-stability of the direct image with respect to any Kähler form on the parameter space.

     

Interactions between metal ions and carbohydrates. Coordination behavior of neutral erythritol to Ca(II) and lanthanide ions

The study of the sugar-metal ion interactions remains one of the main objectives of carbohydrate coordination chemistry because the interactions between metal ions and carbohydrates are involved in many biochemical processes. This paper presents a comparison of coordination structures of erythritol with alkaline-earth-metal and lanthanide chloride and nitrate in the solid state using FT-IR and X-ray diffraction. Neutral, nondeprotonated erythritol (E) reacts with CaCl(2) to give three CaCl(2)(-)erythritol (CaE(I), CaE(II), CaE(III)) complexes, showing that three of the five general features of calcium-carbohydrate complexes deduced in the reference encounter contrary examples. Different coordination structures have been observed for calcium and lanthanide chloride and nitrates. The coordination of carbohydrates to metal ions is complicated, and erythritol, chloride ions, nitrates, water molecules, and ethanol (crystallization medium and reaction solvents) have the chance to coordinate to metal ions. IR spectral results show that different lanthanide ions, from LaCl(3) to TbCl(3), have similar coordination structures with erythritol. The results show that erythritol can act as two bidentate neutral ligands (CaE(I), CaE(II), CaE(III), CaEN, PrE, NdE) or as a three-hydroxyl donor (NdEN). The IR results are consistent with the crystal structures.     

具时滞的奇异(n-1,1)共轭边值问题的多重正解

Abstract. This paper discusses the singular (n-l, 1) conjugate boundary value problem as fol-lows by using a fixed point index theorem in cones     

复杂网络上灾害蔓延动力学研究

针对关键生命线系统，如电网、供水网、供气网、交通网、通信网等的一些共性特征，建立一个普适性的灾害蔓延动力学模型. 这个模型考虑网络结点的自修复功能、灾害蔓延机制和内部随机噪声，并研究自修复因子、延迟时间因子和噪声强度三个重要特征参数对三种网络(随机网络、无标度网络和小世界网络)结点修复率和崩溃结点数的影响. 模拟结果与这些实际生命线系统的特征一致，表明所建立的模型可以有效地模拟生命线系统的灾害演化动力学. 关键词： 复杂网络 生命线系统 灾害蔓延     

Chiral extrapolation of lattice data for B-meson decay constant

The B-meson decay constant f_B has been calculated from unquenched lattice QCD in the unphysical region. For extrapolating the lattice data to the physical region, we propose a phenomenological functional form based on the effective chiral perturbation theory for heavy mesons, which respects both the heavy quark symmetry and the chiral symmetry, and the non-relativistic constituent quark model which is valid at large pion masses. The inclusion of pion loop corrections leads to non-analytic contributions to f_B when the pion mass is small. The finite-range regularization technique is employed for the re-summation of higher-order terms of the chiral expansion. We also take into account the finite volume effects in lattice simulations. The dependence on the parameters and other uncertainties in our model are discussed. PACS 12.39.Fe; 12.39.Hg; 12.39.-x; 12.38.Gc     

碳纳米管束中的正电子理论

采用中性原子叠加模型和有限差分方法(SNA-FD)计算了大范围内不同管径的单壁碳纳米管束中的正电子情况，发现对于单壁碳纳米管束，正电子的主要湮没区域，湮没对象和正电子寿命随碳纳米管管径的不同而发生规律性变化.计算得到管径范围在0.8—1.6nm的碳纳米管束的正电子寿命范围为332—470ps，与实验测得的394ps符合较好.     

In situ variable temperature X-ray diffraction studies on the transformations of nano-precursors to La-Ni-O phases

In situ variable temperature XRD (VT-XRD) measurements on the transformation of nano-precursors to LaNiO phases are presented. Experimental results showed that LaNiO₃ and La₂NiO₄ phases were formed at ca. 700 °C via the reaction of La₂O₃ and NiO (from the initial nano-precursors), where a relatively low temperature of 700 °C was found for the synthesis of La₂NiO₄. The formation of La₃Ni₂O₇ at higher temperature (up to 1150 °C) appeared to proceed through a further reaction of La₂NiO₄ with unreacted NiO, whilst the formation of La₄Ni₃O₁₀ (at 1075 °C) proceeded via a further decomposition of LaNiO₃. Although phase pure La₃Ni₂O₇ and La₄Ni₃O₁₀ were not directly obtained under the processing conditions herein, the results of this study allow for a better understanding of formation pathways, particularly for the higher order La-Ni-O phases.