D. Liu and X. Zhu,Erratum to: “Fractional chromatic number and circular chromatic number for distance graphs with large clique size”. Journal of Graph Theory47(2) 2004, 129–146

The original article to which this Erratum refers was published in Journal of Graph Theory 47:129–146,2004 .     

胶子重组函数的性质

通过协变和非协变的方法研究了领头对数近似(LLA)下扭度为4的QCD演化方程中的胶子重组函数的性质.指出了GLRMQ方程中的胶子重组函数并不适用.讨论了避免红外发散的方法,这种方法可以用于高扭度下演化核和系数函数的推导.     

Efficient Oxidation of Alcohols with Potassium Permanganate Adsorbed on Aluminum Silicate Reagent

A new reagent, potassium permanganate adsorbed on aluminum silicate, suitable for the oxidation of primary and secondary alcohols to the corresponding carbonyl compounds is described.     

Mesoscopic details of crack tip deformation field by application of differential interference contrast method

An experimental method is developed to examine the near tip deformation at the mesoscopic scale level. The differential interference contrast (DIC) method is used by application of the Nomarski prism in polarized microscope for measuring the out of surface deformation. The method is very sensitive to small height changes detected by different interference color. Discussed are results for the crack tip deformation field.     

Synthesis of a soluble pyrrole copolymer with phenetidine

A new series of copolymers was synthesized through the oxidative polymerization of pyrrole (PY) and o‐phenetidine (PHT) with inorganic oxidants in acidic media. The polymerization parameters including the mixing method of the oxidant with the comonomer, the comonomer ratio, the time, the temperature, the oxidant, the organic medium, and the acid were systematically optimized for the synthesis of copolymers with high yields, intrinsic viscosities, and solubility. The resultant copolymers were characterized by elemental analysis, infrared, ultraviolet–visible, solution high‐resolution ¹H NMR and solid‐state high‐resolution ¹³C NMR, circular dichroism spectroscopy, and cyclic voltammetry. The results showed that the PY observed content in the copolymers was much higher than the PY feed content. The regular variation of the polymerization yield, intrinsic viscosity, solubility, macromolecular structure, and electroactivity of the resulting polymers with the comonomer ratio, together with the complete solubility of a PY/PHT (10/90) polymer in highly polar solvents, indicated the formation of real random copolymers containing both PY and PHT units rather than a mixture of two homopolymers. However, the polymers containing more than 59 mol % PY were not homogeneous copolymers consisting of soluble and insoluble parts. A semiquantitative relationship between the polymerization yield or solubility of the copolymers and the polarity index of the organic solvents was examined. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2073–2092, 2004     

Influence of solvents on the formation of ultrathin uniform poly(vinyl pyrrolidone) nanofibers with electrospinning

Although there have been many reports on the preparation and applications of various polymer nanofibers with the electrospinning technique, the understanding of synthetic parameters in electrospinning remains limited. In this article, we investigate experimentally the influence of solvents on the morphology of the poly(vinyl pyrrolidone) (PVP) micro/nanofibers prepared by electrospinning PVP solution in different solvents, including ethanol, dichloromethane (MC) and N,N‐dimethylformamide (DMF). Using 4 wt % PVP solutions, the PVP fibers prepared from MC and DMF solvents had a shape like a bead‐on‐a‐string. In contrast, smooth PVP nanofibers were obtained with ethanol as a solvent although the size distribution of the fibers was somewhat broadened. In an effort to prepare PVP nanofibers with small diameters and narrow size distributions, we developed a strategy of using mixed solvents. The experimental results showed that when the ratio of DMF to ethanol was 50:50 (w/w), regular cylindrical PVP nanofibers with a diameter of 20 nm were successfully prepared. The formation of these thinnest nanofibers could be attributed to the combined effects of ethanol and DMF solvents that optimize the solution viscosity and charge density of the polymer jet. In addition, an interesting helical‐shaped fiber was obtained from 20 wt % PVP solution in a 50:50 (w/w) mixed ethanol/DMF solvent. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3721–3726, 2004     

Viscosity,particle size distribution,and structural investigation of tetramethyloxysilane/2‐hydroxyethyl methacrylate sols during the sol–gel process with acid and base catalysts

The tetramethoxysilane (TMOS)/2‐hydroxylethyl methacrylate (HEMA) hybrid gels were synthesized with acid and base catalysts, via the in situ polymerization of HEMA, with and without the cosolvent methanol. With methanol in the TMOS/HEMA sol, the enhanced esterification and depolymerization reactions of the silanols resulted in a slower growth of silica particles. The silica particles that were synthesized with an acid catalyst were less than 40 nm. The thermal resistance of the poly(2‐hydroxyethyl methacrylate) (PHEMA) chains was enhanced by the addition of colloidal silica. The Fourier transform infrared characterizations and the exothermal peaks on the differential scanning calorimetry traces of these hybrid gels indicated chemical hybridization occurring as a result of condensation of the colloid silica and PHEMA at higher temperatures. Hence, the residual weight content of the hybrid gel after its synthesis with the base catalyst was even higher than the content of TMOS in the hybrid sol. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3476–3486, 2004     

Distributions of major-to-ultratrace elements among the particulate and dissolved fractions in natural water as studied by ICP-AES and ICP-MS after sequential fractionation.

In order to elucidate the distributions of the elements among the particulate and dissolved fractions in pond water, major-to-ultratrace elements in different sizes of particles as well as in the filtrate passed through the 0.05 microm filter were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). The different sizes of particle samples (ca. 100-300 microg each) were collected on the membrane filters with pore sizes of 10, 3.0, 1.2, 0.4, 0.2 and 0.05 microm, respectively, by sequential fractionation. As a result, about 40 elements in different sizes of particles could be determined by ICP-AES and ICP-MS, after acid digestion using HNO3/HF/HClO4. Then, the fractional distribution factors of major-to-ultratrace elements among the particulate and dissolved fractions were estimated from the analytical results. The total contents of Al, Fe, Ti, REEs (rare earth elements), Bi, Pb and Ag in the particulate fractions (larger than 0.05 microm) were more than 80-90%, while those of Ca, Sr, Cs, W, Ba, Mn and Co in the dissolved fraction, which corresponded to the filtrate passed through the 0.05 microm membrane filter, were more than 80%. It was further found that the fractional distributions of Cu and Zn in the dissolved fraction were ca. 50%. In addition, the enrichment factors (EFs) of the elements in the particulate fractions with particle sizes of 3.0-10 microm and 0.05-0.2 microm were estimated to elucidate their geochemical characteristics in natural water.     

Estimation of kinetics parameters for the adsorption of human serum albumin onto hydroxyapatite-modified silver electrodes by piezoelectric quartz crystal impedance analysis.

The adsorption of human serum albumin onto hydroxyapatite-modified silver electrodes has been in situ investigated by utilizing the piezoelectric quartz crystal impedance technique. The changes of equivalent circuit parameters were used to interpret the adsorption process. A kinetic model of two consecutive steps was derived to describe the process and compared with a first-order kinetic model by using residual analysis. The experimental data of frequency shift fitted to the model and kinetics parameters, k1, k2, psi1, psi2 and qr, were obtained. All fitted results were in reasonable agreement with the corresponding experimental results. Two adsorption constants (7.19 kJ mol(-1) and 22.89 kJ mol(-1)) were calculated according to the Arrhenius formula.     

螺旋线径向挤压变形对其慢波结构冷测特性的影响

 介绍了用MAFIA软件的准周期边界条件计算螺旋线行波管慢波结构的色散和耦合阻抗，以及用ANSYS软件对螺旋线径向挤压变形建模的方法，并对螺旋线受挤压径向变形对其冷测特性的影响进行了详细的分析。结果表明:螺旋线径向挤压变形会导致相速增大，而在通常的变形范围内耦合阻抗也会增加；当变形继续增大时耦合阻抗上升到最大值后开始下降。