乙二胺导向合成的微孔晶体磷酸钴的转化现象

以乙二胺为模板剂(SDA)合成微孔晶体磷酸钴, 可以得到多种不同的结构. 本文在合成四种不同结构类型的微孔磷酸钴(命名为CoPO-en-1, CoPO-en-2, CoPO-en-3, CoPO-en-4, en 为乙二胺的英文缩写)过程中发现, 它们之间不仅可以在水热合成条件下相互转化, 在焙烧处理条件下也能实现转化. 研究发现, 在水热合成过程中, CoPO-en-2、CoPO-en-4 分别是CoPO-en-1、CoPO-en-3 的晶化中间物, 在较低晶化温度下或者较高温度的晶化初期, 可以发现它们的身影. 一旦晶化温度升高或者晶化时间延长, 它们就分别转化为CoPO-en-1和CoPO-en-3. 在合成产物的热处理过程中发现: CoPO-en-2、CoPO-en-3、CoPO-en-4 都能够通过焙烧转化为CoPO-en-1. 这种现象表明, 几种微孔磷酸钴结构间的稳定性存在递变关系.     

Equitable Vertex Arboricity Conjecture Holds for Graphs with Low Degeneracy

The equitable tree-coloring can formulate a structure decomposition problem on the communication network with some security considerations. Namely, an equitable tree-k-coloring of a graph is a vertex coloring using k distinct colors such that every color class induces a forest and the sizes of any two color classes differ by at most one. In this paper, we show some theoretical results on the equitable tree-coloring of graphs by proving that every d-degenerate graph with maximum degree at most Δ is equitably tree-k-colorable for every integer k ≥(Δ + 1)/2 provided that Δ≥ 9.818 d,confirming the equitable vertex arboricity conjecture for graphs with low degeneracy.     

On the Mixed Pólya–Szeg? Principle

In this paper,the mixed Pólya-Szeg? principle is established.By the mixed Pólya-Szeg? principle,the mixed Morrey-Sobolev inequality and some new analytic inequalities are obtained.     

Entanglement dynamics of two qubits coupled by Heisenberg XY interaction under a nonuniform magnetic field in a spin bath

This paper investigates the entanglement dynamics of a Heisenberg XY model for a two-spin system in the presence of a nonuniform magnetic field.The master equations and the concurrence evolution equations for the initial α state are derived and analysed.It is shown that for the symmetric initial α state,only the nonuniform field can play a role in entanglement dynamics while the uniform field and the bath will not play such a role.For the asymmetric α state,the nonuniform field leads to the beat pattern oscillation of the concurrence evolution.The inhomogeneity of the field can enhance the entanglement by suppressing the decoherence effects of both the spin-orbit interaction and the spin bath.     

A Comprehensive Therotical Investigation of Intramolecular Proton Transfer in the Excited States for Some Newly-designed Diphenylethylene Derivatives Bearing 2-(2-Hydroxy-Phenyl)-Benzotriazole Part

This article presents a comprehensive therotical investigation of excited state intramolecular proton transfer (ESIPT) for some newly-designed diphenylethylene derivatives containing 2-(2-hydroxy-phenyl)-benzotriazole moiety with various substituted groups. The calculation shows the structural parameters and Mulliken charges of phototautomers enol (E) and keto (K) of these compounds exhibit no or tiny changes from S₀ to S₁. The calculated results suggest that HOMO and LUMO + 1 of the compounds displays excellent overlapping nature, and thus the absorption and emission could be from the electron transition of HOMO→LUMO + 1. The electron density distribution in the frontier orbital of E and K are influenced remarkably by various substituted groups in S₀ and S₁ states. Electron density distribution deficiency in 2-(2-hydroxy-phenyl)-benzotriazole part is observed in L + 1 for these derivatives. The calculation also suggests the potential energy curves of ESIPT are shown to be a strong relationship with electron donor-acceptor groups. The absorption spectra, normal emission spectra and ESIPT spectra of the derivatives were also calculated.     

Pulse characteristics of passively Q-switched 1.34 μm Nd:GdVO<Subscript>4</Subscript>/Co<Superscript>2+</Superscript>:MgAl<Subscript>2</Subscript>O<Subscript>4</Subscript> laser

Passively Q-switched output of a diode-pumped 1.34 μm Nd:GdVO₄ laser was demonstrated by using Co²⁺:MgAl₂O₄(Co²⁺:MALO) crystal as the saturable absorber for the first time. When the transmission of output mirror is 15%, the Q-switched pulse width is 110 ns and a corresponding average output power is 460 mW under the pump power of 9.69 W. The optical-optical conversion efficiency is 36%. At about 330 kHz repetition rate, the single Q-switched pulse energy and the peak power are about 1.39 μJ and 12.6 W, respectively.     

Synthesis and photoinduced electron transfer characteristic of a bis (zinc porphyrin)‐perylene bisimide array

In this article, a donor–acceptor array consisting of two zinc porphyrin (ZnPOR) units attached to the 1,7‐positions of perylene‐3,4:9,10‐bis(dicarboximide) (PDI) was synthesized and characterized. This double‐wing molecule exhibits very broad absorption in the region from 300 to 900 nm. Especially, its lower energy absorption feature presumably arises from donor–acceptor interactions. The fluorescence emission spectra confirmed that photoinduced electron transfer occurred from POR to perylene bisimide moiety in this triad. In contrast to previously studied systems incorporating POR and PDI groups, this array shows the evidence of a relatively strong ground‐state electronic coupling between the donor and acceptor moieties. Additionally, highest occupied molecular orbital and lowest unoccupied molecular orbital values of the array were acquired by cyclic voltammetry (CV). The results showed that these energy values fulfill the energetic conditions required for the proposed electron transfer. More importantly, the photocurrent measurement showed that this molecule exhibits a high capacity to form a photoinduced charge‐separated state and to produce steady and prompt cathodic photocurrent responses. These results confirmed the role of this new array toward harvesting light energy and generating photocurrent during the operation of a photoelectrochemical cell. Copyright © 2011 John Wiley & Sons, Ltd.     

Unique continuation properties for generalized Baouendi-Grushin operators with singular weights

In this paper, properties of the spherical functions and Hardy-Sobolev inequalities of generalized Baouendi-Grushin vector fields are established, and then some unique continuation results for generalized Baouendi-Grushin operators with singular weights are given.     

On first order interpolation inequalities with weights on the Heisenberg group

In this paper, sufficient and necessary conditions for the first order interpolation inequalities with weights on the Heisenberg group are given. The necessity is discussed by polar coordinates changes of the Heisenberg group. Establishing a class of Hardy type inequalities via a new representation formula for functions and Hardy-Sobolev type inequalities by interpolation, we derive the sufficiency. Finally, sharp constants for Hardy type inequalities are determined.