Photophysical Properties of Sol–gel derived Luminescent Silicone Hybrids Synthesized via Facile Amino‐Ene Reaction

Novel luminescent silicone hybrids (LSHs) containing lanthanide ions were prepared via different sol–gel processes. The precursor, dimethyl ester‐functionalized silane, was synthesized via a facile amino‐ene reaction. The coordinated assembly of the ester ligands and lanthanide ions (Eu³⁺, Tb³⁺ and Dy³⁺) occurred. The ester ligands were immobilized onto the Si‐O network backbone during the preparation of the silicone hybrid materials. The particle size can be controlled to ca 50 nm by adjusting the solvent ratio. The obtained materials were characterized by Fourier transform infrared, ¹H nuclear magnetic resonance spectroscopy (NMR), ¹³C NMR, ²⁸Si NMR, X‐ray diffraction, X‐ray photoelectron spectroscopy, thermogravimetric analysis, high‐resolution scanning electronic microscopy and luminescent (excitation and emission) spectroscopy. The coordination state and photophysical performance of the compounds were studied in detail. The terbium‐ and europium‐containing materials show sharp green and red emissions, respectively, which indicate that efficient intramolecular energy transfer took place in these LSHs.     

Experimental Verification of Left-Handed Metamaterials Composed of Coplanar Electric and Magnetic Resonators

We verified experimentally left-handed metamaterials （LHM） composed of coplanar electric and magnetic resonators. A typical LHM sample composed of coplanar resonator unit cells was fabricated, investigated and tested. The experimental results show that the tested sample has a left-handed band of width 1.4 GHz in the X band. The experimental results agree quite well with the simulation ones. Moreover, both the simulation and experimental results show that the LHM under study can automatically achieve good impedance-matching in the left-handed band.     

On the moment of inertia of a proto neutron star

The influences of σ* and Φ mesons,temperature and coupling constants of nucleons on the moment of inertia of the proto neutron star(PNS) are examined in the framework of relativistic mean field theory for the baryon octet {n,p,Λ,Σ+,Σ0,Σ+,Ξ-,Ξ0} system.It is found that,compared with that without considering σ* and Φ mesons,the moment of inertia decreases.It is also found that the higher the temperature,the larger the incompressibility and symmetry energy coeficient,and the larger the moment of inertia of a PNS.The influence of temperature and coupling constants of the nucleons on the moment of inertia of a PNS is larger than that of the σ* and Φ mesons.     

Controlling bifurcations and chaos in TCP–UDP–RED

We study the bifurcation and chaotic behavior of the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) network with Random Early Detection (RED) queue management. These bifurcation and chaotic behaviors may cause heavy oscillation of an average queue length and induce network instability. We propose an impulsive control method for controlling bifurcations and chaos in the internet congestion control system. The theoretical analysis and the simulation experiments show that this method can obtain the stable average queue length without sacrificing the other advantages of RED.     

Morlet小波在确定局部周期中的应用

本文通过引入改进的Morlet小波变换核函数,得到了等幅值的Morlet小波变换(MMWT)和功率谱(MMPS).理论及实验均表明,MMPS不但能够准确的确定信号的局部周期,而且使相同振幅(强度)的谐波产生了相同大小的MMPS,弥补了MPS的不足.对于MMWT还给出了相应的Morlet小波变换尺度与频率转化公式.     

Study of association thermodynamics between crystal violet and sodium bis(2-ethylhexyl)sulfosuccinate and kinetics of basic fading of crystal violet in microemulsions

The thermodynamics of the association between 4,4′,4″-tris(dimethyl-amino)triphenylmethyl chloride (crystal violet or CV) and sodium bis(2-ethylhexyl)-sulfosuccinate (aerosol OT or AOT) in water/AOT/n-decane microemulsion and the kinetics of the basic hydrolysis of CV in a water-in-oil microemulsion were investigated by UV–vis spectroscopic measurements. An association model of CV and AOT was used to analyze the experimental data to obtain the association constants at various temperatures. By taking the association into account, the “actual” rate constants and the activation energies of the basic hydrolysis of CV in the media of water/AOT/oil were obtained. The difference in thermodynamics and kinetics between the two media of water/AOT/n-decane and water/AOT/isooctane is discussed. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 294–300, 2008     

A new synthesis of alkynyl tellurides promoted by CsOH and 4(A°) MS

The mixture of cesium hydroxide and terminal alkynes in dry DMF in the presence of 4(A°), molecular sieves was stirred for 3.0 h at room temperature under N2, then aryltellurenyl bromide in THF was added, and the reaction mixture was stirred for 2.0 h. Alkynyl tellurides were obtained in about 90% yields by flash chromatography.     

A unified method for a class of convex separable nonlinear knapsack problems

In this paper, a unified algorithm is proposed for solving a class of convex separable nonlinear knapsack problems, which are characterized by positive marginal cost (PMC) and increasing marginal loss–cost ratio (IMLCR). By taking advantage of these two characteristics, the proposed algorithm is applicable to the problem with equality or inequality constraints. In contrast to the methods based on Karush–Kuhn–Tucker (KKT) conditions, our approach has linear computation complexity. Numerical results are reported to demonstrate the efficacy of the proposed algorithm for different problems.