Adsorption and dissociation of O2 on the Cu2O(1 1 1) surface: Thermochemistry, reaction barrier

The adsorption and dissociation of O₂ on the perfect and oxygen-deficient Cu₂O(1 1 1) surface have been systematically studied using periodic density functional calculations. Different kinds of possible modes of atomic O and molecular O₂ adsorbed on the Cu₂O(1 1 1) surface are identified: atomic O is found to prefer threefold 3Cu site on the perfect surface and O_vacancy site on the deficient surface, respectively. Cu_CUS is the most advantageous site with molecularly adsorbed O₂ lying flatly over singly coordinate Cu_CUS-Cu_CSA bridge on the perfect surface. O₂ adsorbed dissociatively on the deficient surface, which is the main dissociation pathway of O₂, and a small quantity of molecularly adsorbed O₂ has been obtained. Further, possible dissociation pathways of molecularly adsorbed O₂ on the Cu₂O(1 1 1) surface are explored, the reaction energies and relevant barriers show that a small quantity of molecularly adsorbed O₂ dissociation into two O atoms on the deficient surface is favorable both thermodynamically and kinetically in comparison with the dissociation of O₂ on the perfect surface. The calculated results suggest that the presence of oxygen vacancy exhibits a strong chemical reactivity towards the dissociation of O₂ and can obviously improve the catalytic activity of Cu₂O, which is in agreement with the experimental observation.     

X-Y振镜扫描式舌诊高光谱采集系统

针对目前舌诊研究中在舌体信息全面获取方面存在严重不足,将高光谱技术用到舌诊的研究中来,提出了一种基于X-Y振镜扫描式舌诊高光谱采集系统.通过模拟实验,采集与舌体大小相似图片的高光谱信息,验证了该系统可以用于舌体高光谱信息采集,实验结果表明,与现有舌诊客观化研究相比,该系统可以获得更多的舌体信息,为舌诊客观化研究提供了一...     

超Li系统的Bargmann对称约束和双非线性化

给出超Li系统的一个显式对称约束和关于其Lax对的双非线性化.在此对称约束下,超Li系统的时间部分和空间部分分别被约化为有限维Liouville可积超Li系统.     

Weighted pseudo almost periodic solutions of N-th order neutral differential equations with piecewise constant arguments

In this work, we present some existence theorems of weighted pseudo almost periodic solutions for N-th order neutral differential equations with piecewise constant argument by means of weighted pseudo almost periodic solutions of relevant difference equations.     

The relation and transformation between hierarchical inner product encryption and spatial encryption

Hierarchical inner product encryption (HIPE) and spatial encryption (SE) are two important classes of functional encryption that have numerous applications. Although HIPE and SE both involve some notion of linear algebra, the former works in vectors while the latter is based on (affine) spaces. Moreover, they currently possess different properties in terms of security, anonymity (payload/attribute-hiding) and ciphertext sizes, for example. In this paper, we formally study the relation between HIPE and SE. In our work, we discover some interesting and novel property-preserving transformation techniques that enable generic construction of an SE scheme from an HIPE scheme, and vice versa.     

扩散模型中扩散系数的非参数组合估计

为了提高扩散系数估计的准确度, 我们利用动态组合时间域与状态域信息提出一个新的组合估计量. 我们发现所提组合估计量能有效估计扩散模型的扩散系数, 正如在本文中模拟所示. 在一定的条件下, 建立了估计量的渐进正态性, 并证明了时间域估计量与状态域估计量是渐进独立的. 大量的模拟展示了所提组合估计量优于单域估计量, 也优于本文所提估计量.     

一类无穷下级整函数的Julia集的径向分布

主要研究方程f"(z)+A(z)f'(z)+B(z)f(z)=0(A(z)),B(z)为整函数)的解、解的多项式或微分多项式这些具有无穷下级的整函数的Julia集的径向分布问题.     

Structural characterization of poly(amino)ester dendrimers and related impurities by electrospray tandem mass spectrometry

An acid‐terminated poly(amino)ester dendrimer was studied by electrospray ionization tandem mass spectrometry to establish its fragmentation pathways, with the aim of using them to investigate the structure of any defective molecules generated during the dendrimer synthesis. This poly(amino)ester dendrimer could be ionized in both polarities but the most structurally relevant dissociation pathways were found from the deprotonated molecule in negative ion mode. The dissociation pattern of this dendrimer is fully described and supported by accurate mass measurements. The main dissociation reactions of the negatively charged polyacidic dendrimer were shown to consist of (i) the release of carbon dioxide and ethene within a branch, which proceeds as many times as intact neutral branches are available; and (ii) the elimination of an entire dendrimer arm. Monitoring the occurrence of these reactions together with any deviation from these two main routes allowed six major dendritic impurities to be structurally characterized. Copyright © 2010 John Wiley & Sons, Ltd.     

Two New Dawson-Type Polyoxometalates: 1D Chain Made by Mono-Dawson Units and 2D Layer Made by Double-Dawson Units

Abstract  

Two new Dawson-Type POTs, (H₂en)H₂[Cu(en)₂][Cu(en)(H₂O)₃][Cu(en)₂ (H₂O)](P₂W₁₇CuO₆₁)·8H₂O (1, en = ethylenediamine) and H₁₀K₆(P₂W₁₇CuO₆₁)₂·34H₂O (2), have been synthesized under hydrothermal conditions and characterized by IR spectroscopy, TG, XRD and single-crystal X-ray structural analysis. Crystal data for 1: triclinic, P[`1] {P}{\bar{1}} , a = 11.6855(26) ?, b = 13.2679(29) ?, c = 28.1540(60) ?, α = 80.4009(75)°, β = 82.5150(79)°, γ = 67.1482(46)°, Z = 2. Crystal data for 2: monoclinic, C2/c, a = 43.5701(99) ?, b = 12.3078(25) ?, c = 29.3742(66) ?, β = 101.3749(21)°, Z = 4. Compound 1 exhibits a 1D chain, in which the [Cu(en)₂]²⁺ cations act as the linkages of mono-{P₂W₁₇Cu} units. Compound 2 shows a 2D layer, in which the double-Dawson units are connected by K⁺ cations.