界面缩聚法制备间苯二甲酰双酚酸酯聚芳酯

以四丁基氯化铵为相转移催化剂,双酚酸甲酯或双酚酸乙酯与间苯二甲酰氯界面缩聚,合成得到了侧链含酯基的聚芳酯.在吡啶、三乙胺、碳酸氢钠、氢氧化钠中选择合适的催化剂,既可以发生聚合反应又不会使双酚酸酯的酯基发生水解.聚合反应在7种溶剂中进行,通过探讨聚合反应机理以解释溶剂对聚合反应产率以及聚合物特性黏数的影响.以二氯甲烷为溶剂,在优化的聚合条件下较高产率地得到了高特性黏数的聚合物.DSC及TGA分析表明,间苯二甲酰双酚酸酯类聚芳酯具有比间苯二甲酰双酚酸好的热稳定性,热分解温度可从200℃提高到300℃.     

Numerical simulation of Richtmyer-Meshkov instability

The compressible Navier-Stokes equations discretized with a fourth order accurate compact finite difference scheme with group velocity control are used to simulate the Richtmyer-Meshkov (R-M) instability problem produced by cylindrical shock-cylindrical material interface with shock Mach number Ms=1.2 and density ratio 1:20 (interior density/outer density). Effect of shock refraction, reflection, interaction of the reflected shock with the material interface, and effect of initial perturbation modes on R-M instability are investigated numerically. It is noted that the shock refraction is a main physical mechanism of the initial phase changing of the material surface. The multiple interactions of the reflected shock from the origin with the interface and the R-M instability near the material interface are the reason for formation of the spike-bubble structures. Different viscosities lead to different spike-bubble structure characteristics. The vortex pairing phenomenon is found in the initial double mode simulation. The mode interaction is the main factor of small structures production near the interface.

     

Kinetics and Modeling of Vinyl Acetate Graft Polymerization from Poly(ethylene glycol)

A kinetic model for the graft polymerization of VAc from PEG was developed using the method of moments. Experiments were carried out to verify the model. The effect of various parameters, such as initiator concentration, temperature, and PEG molecular weight on the polymerization kinetics was examined. Polymerization rate, grafting efficiency, graft copolymer molecular weight, and PEG grafted ratio were measured. The model was in good agreement with the experimental data. No gel effect was observed at the studied PEG/VAc weight ratio of 1:1. The chain transfer constant to PEG was correlated to be . The model was also applied in a semi‐batch reaction and compared with the experimental results.

     

Preparation and SO2 Absorption/Desorption Properties of Crosslinked Poly(1,1,3,3‐Tetramethylguanidine Acrylate) Porous Particles

Summary: Novel crosslinked porous particles based on the ionic copolymer of 1,1,3,3‐tetramethylguanidine acrylate (TMGA) and N,N‐methylenebisacrylamide (MBA) were prepared via an inverse suspension polymerization using cyclohexane as continuous phase and Span 60 as the dispersant. The SO₂ absorption–desorption properties of the P(TMGA‐co‐MBA) particles were studied for the first time. The particles showed excellent SO₂ absorption properties: high capacity and rate. These absorption properties, as well as the particle volume, shape, and morphology, remained unchanged during the SO₂ absorption–desorption cycles. The material appeared to be a good candidate as SO₂ absorbent for fuel gas desulfurization (FGD) and purification of other SO₂‐containing gases.

Optical microscope image of the P(TMGA‐co‐MBA) porous particles.     

Speciation of Fe(III) and Fe(II) in water samples by liquid–liquid extraction combined with low-temperature electrothermal vaporization (ETV) ICP-AES

The use of 1-phenyl-3-methyl-4-benzoylpyrazolone (PMBP) as extractant for separation of Fe(III) and Fe(II) and low-temperature vaporization of the Fe(III)–PMBP chelate into ICP-AES for their speciation analysis was investigated. The factors affecting the formation of Fe(PMBP)₃ chelate and its vaporization behavior were investigated in detail. PMBP was used not only as the extractant for the separation of Fe(III) and Fe(II) but also as the chemical modifier for the low-temperature ETV-ICP-AES determination of iron. Under the optimized conditions, the detection limit for iron(III) and iron(II) are both 3.2?ng/mL, with relative standard deviations of 3.9 and 4.5%, respectively. The proposed method was applied to the determination of trace iron in biological standard reference materials and the species in East Lake water samples, and the results obtained were satisfactory.     

衍射微透镜列阵的研究与应用

本文研究了衍射微透镜列阵的设计与制作工艺方法，在此基础上研制出一系列衍射微透镜列阵，衍射效率均大于８５％，在深紫外、可见及红外波前传感器中得到了成功应用。     

可燃气体检测报警器计量检定与计量管理的探讨

指出了可燃气体检测报警器计量检定的重要性,结合河南省南阳市辖区内可燃气体检测报警器计量检定的现状,着重分析了计量检定与计量管理存在的问题和难点,并且提出了相关建议。     

Regio- and stereoselective synthesis of highly functionalized vinyl ethers via coiodination of acetylenic ketones

A Cu(OTf)₂-catalyzed highly regio- and stereoselective coiodination of acetylenic ketones was reported, providing a mild and convenient method for the synthesis of (Z)-β-carbonyl-β-iodoenol ethers in good yields.     

Stochastic bounded consensus tracking of leader–follower multi-agent systems with measurement noises based on sampled-data with small sampling delay

This paper is concerned with the stochastic bounded consensus tracking problems of leader–follower multi-agent systems, where the control input of an agent can only use the information measured at the sampling instants from its neighborhood agents or a virtual leader with a time-varying reference state, the measurements are corrupted by random noises, and the signal sampling process induces a small sampling delay. The augmented matrix method, probability limit theory and algebra graph theory are employed to derive the necessary and sufficient conditions guaranteeing mean square bounded consensus tracking. It turns out that the convergence of the proposed protocol simultaneously depends on the constant feedback gains, the network topology, the sampling period and the sampling delay, and that the static consensus tracking error depends on not only the above-mentioned factors, but also the noise intensity, the number of agents and the upper bound of the changing rate of the virtual leader’s state. The obtained results cover no sampling delay as a special case. Simulations are provided to demonstrate the effectiveness of the theoretical results.