聚苯乙烯非晶区结构的RDF研究

本文介绍了以X-射线衍射法测定非品区结构的径向分市函数RDF方法，并将其应用于聚苯乙烯（PS）非晶区的结构研究．     

Microwave-assisted synthesis and in-situ self-assembly of coaxial Ag/C nanocables

We have successfully developed a new one-pot solution-phase route, namely microwave-assisted hydrothermal reduction/carbonization (MAHRC), for a rapid synthesis of coaxial Ag/C nanocables. The nanocables can self-assemble in situ in an end-to-end fashion into interconnected chains.     

Speciation of dissolved iron(II) and iron(III) in environmental water samples by gallic acid-modified nanometer-sized alumina micro-column separation and ICP-MS determination

A method has been developed for the speciation of trace dissolved Fe(II) and Fe(III) in water by coupling gallic acid (GA) modified nanometer-sized alumina micro-column separation with inductively coupled plasma mass spectrometry (ICP-MS). The separation of Fe(II) and Fe(III) was achieved based on the obvious difference in reaction kinetics between Fe(II) and Fe(III) with GA. Fe(III) was selectively retained on the micro-column at pH 5.5-6.5, while Fe(II) could not be retained by the micro-column at the whole tested pH range of 1.0-6.5, and passed through the micro-column. The Fe(II) can be determined by ICP-MS directly without preconcentration/separation procedure, while Fe(III) retained on the micro-column was then eluted with 1.0 mL of 1 mol L(-1) HCl and determined by ICP-MS. The parameters affecting the separation of Fe(II) and Fe(III) were investigated systematically and the optimum separation conditions were established. Under the optimized conditions, the detection limits of 0.48 microg L(-1) and 0.24 microg L(-1) with relative standard deviation of 5.6% and 4.3%(C= 5 microg L(-1), n= 7) for Fe(II) and Fe(III) were found, respectively. No obvious effect on the speciation of Fe(II) and Fe(III) was found with the change of the ratio of Fe(II) and Fe(III) from 0 ratio 10 to 10 ratio 0. The proposed method was applied for the determination of trace Fe(II) and Fe(III) in environmental water and the recoveries for spiked samples were found to be in the range of 97-105%.     

涂敷法制作质谱场电离发射丝的方法及性能研究

本文介绍一种新的质谱场电离发射丝的制备方法——涂敷法,并研究了其制备机理及影响发射丝灵敏度的因素。此外,还对涂敷法制作的发射丝及高温活化法制作的发射丝进行了各项性能对比试验。最后,介绍了涂敷发射丝的应用效果。     

1,2,2,6,6-五甲基哌啶醇对聚丙烯光稳定作用的研究

<正> 关于受阻胺类光稳定剂的稳定作用机理,是近年来光稳定研究领域中广泛探讨的课题,我们用异辛烷溶液研究了1,2,2,6,6-五甲基哌啶醇的光稳定作用,结果已在前文报道,本工作是上述研究的继续,主要研究五甲基哌啶醇对聚丙烯膜的光稳定作用。     

Transmembrane ion conductance by an acyclic bolaamphiphile

[reaction in text] An acyclic bolaamphiphile forms ion channels in vesicles and planar bilayer membranes that are closely similar to the channels formed by related bismacrocyclic compounds. Thus the function of these ion channels does not depend on synthetically difficult macrocyclic subunits.     

苯乙烯-4-甲基丙烯酰氧-2.2.6.6-四甲基哌啶共聚物的250兆赫~1H-核磁共振研究

本文用250兆赫~1H-核磁共振技术研究了苯乙烯(S)-4-甲基丙烯酰氧-2、2.6.6-四甲基哌啶(M)自由基引发聚合的共聚物的组分比和微结构,定量测定了以M为中心的三元组分布。由此确认该共聚体系属于一级马尔可夫链模型,并确定了单体竞聚率常数,r_M=0.32,r_S=0.60。对苯乙烯含量较多的共聚物还定量估计了以S为中心的三元组分布,与理论上计算结果有很好的一致性。     

Preparation of Small Particle Sized ZnAl-Hydrotalcite-Like Compounds by Ultrasonic Crystallization

Ultrasonic technology has been intensively studied recently due to its special features. In this paper, an ultrasonic crystallization method was introduced for the preparation of ZnAl-Hydrotalcite-Like compounds (ZnAl-HTLcs). Samples with high crystallinity, small particle size and narrow particle size distribution were obtained and fully characterized using conventional techniques of XRD, FT-IR and TGDTA. The results prove that both ultrasonic frequency and ultrasonic power have effects on the sizes of the product particles. By varying the ultrasonic power from 250 W to 88 W, with the ultrasonic frequency fixed at 59 kHz, the median particle size of the samples increased from 0.37 μm to 0.82 μm. By altering the hydrothermal treatment time from 1 h to 5 h at 110℃, the median particle size of ZnAl-HTLcs synthesized via ultrasonic crystallization increased from 0.88 μm to 1.11 μm.     

Dirhodium(II) tetrakis[methyl 2-oxaazetidine-4-carboxylate]: a chiral dirhodium(II) carboxamidate of exceptional reactivity and selectivity

[formula: see text] A new chiral azetidinone-carboxylate ligand for dirhodium(II) catalysis enhances reactivity toward diazo decomposition and selectivity toward cyclopropanation enabling diazomalonates, vinyldiazoacetates, and aryldiazoacetates to be effectively used with a dirhodium(II) carboxamidate catalyst.     

Synthesis and lysozyme adsorption of rod-like large-pore periodic mesoporous organosilica

Highly ordered rod-like large-pore periodic mesoporous organosilica (PMO) was successfully synthesized at low acid concentration with the assistance of inorganic salt using triblock copolymer P123 as a template. The roles of inorganic salt and acidity in the production of highly ordered mesostructure and the morphology control of PMOs were investigated. It was found that the inorganic salt can significantly widen the range of the synthesis parameters to produce highly ordered 2D hexagonal pore structure of p6mm symmetry. However, the uniform rod-like PMOs can only be synthesized in a narrow range of acid and salt concentrations, which were sensitive to induction time. The adsorption of lysozyme on PMO was studied at different pH values in comparison with adsorption on pure silica material under controlled morphology and pore structure. It was found that the adsorption capacity of lysozyme on the PMO was lower than that on pure SBA-15 silica material and the adsorption amounts are larger at pH 9.6 than at 7.0 for both materials. The results show that the electrostatic interaction between lysozyme and PMO/SBA-15 surface is more dominant than the hydrophobic forces and the interaction of neighboring lysozyme molecules also plays an important role.