L—氨基酸氧化酶电极的制作及电极特性的研究

报道了一种新的Ｌ－氨基酸氧化酶电极，这种酶电极系由氨气敏电极和以氨基化玻璃布为载体的酶膜所组成；研究了固定化条件对酶膜活性的影响以及底物浓度、温度和ｐＨ对电极响应特性的影响。该电极在６．０×１０＾－５～４．０×１０＾－３ｍｏｌ／Ｌ的底物浓度范围内呈良好的线性关系，检测下限为５．０×１０＾－５ｍｏｌ／Ｌ。在最宜条件下，酶电极具有良好的稳定性。     

水中酚的膜萃取分离流动注射技术测定的研究

本文提出了硅橡胶膜在线萃取分离流动注射技术测定水样中苯酚的方法。由于水样中的苯酚透过硅橡胶进入萃取液的萃取量随时间的增加和温度的升高而增大，故采用停流技术及升高温度以降低酚的检出限。     

Asymptotic analysis of Daubechies polynomials

To study wavelets and filter banks of high order, we begin with the zeros of . This is the binomial series for , truncated after terms. Its zeros give the zeros of the Daubechies filter inside the unit circle, by . The filter has additional zeros at , and this construction makes it orthogonal and maximally flat. The dilation equation leads to orthogonal wavelets with vanishing moments. Symmetric biorthogonal wavelets (generally better in image compression) come similarly from a subset of the zeros of . We study the asymptotic behavior of these zeros. Matlab shows a remarkable plot for . The zeros approach a limiting curve in the complex plane, which is the circle . All zeros have , and the rightmost zeros approach (corresponding to ) with speed . The curve gives a very accurate approximation for finite . The wide dynamic range in the coefficients of makes the zeros difficult to compute for large . Rescaling by allows us to reach by standard codes.

     

Visual recognition of melamine in milk via selective metallo-hydrogel formation

A novel protocol allowing convenient and highly selective visual recognition of melamine in raw milk via selective metallo-hydrogel formation at a concentration as low as 10 ppm without any tedious pretreatment has been developed.     

槲皮素伏安行为及其稀土络合物极谱催化氢波研究

在乙醇量小于5％的水溶液中，于pH1.5至4.5，4.2至9.5分别得到槲皮素的两个还原波，均为羰基两电子还原．前者为其分子的强吸附波，后者为一价阴离子的波．在pH6.1附近的醋酸盐缓冲底液中，可获得槲皮素与Tb（Ⅲ）、Dy（Ⅲ）、Ho（Ⅲ）、Er（Ⅲ）、Tm（Ⅲ）、Yb（Ⅲ）、Lu（Ⅲ）和Y（Ⅲ）等重稀土离子络合物的双重表面催化氢波．络合物被诱导吸附，组成为（REL_2）L_吸．Sc（Ⅲ）与槲皮素形成单一表面催化氢波，其组成为（ScL）L_吸．     

Preparation and characterization of sulfonated poly(phenylene oxide) proton exchange composite membrane doped with phosphosilicate gels

A new class of proton exchange composite membranes made by incorporating phosphosilicate gels into SPPO matrix was prepared and characterized. The thermal stability was evaluated by TGA and DSC, and the amorphous structure information was provided from XRD. The experimental results showed that the composite membranes have good stability to oxidation by Fenton's reagent test, and the membrane dimension is hardly changed, even at high temperature. The hydration number values of the persulfonic acid group of composite membranes were lower than that of Nafion 112 at room temperature, but the water uptake of composite membranes at 80°C was higher than that of Nafion 112. With increasing relative humidity and doping amount, the conductivity of the composite membranes increased. Moreover, the conductivities of water-equilibrated composite membranes were higher than that of Nafion 112 (0.0871 S/cm) at room temperature, and the highest conductivity for the composite membrane was 0.216 S/cm. Copyright © 2007 John Wiley & Sons, Ltd.     

含IIIA或VA族杂原子的碳原子簇负离子的研究

在自制的仪器上，以脉冲激光束在高真空中溅射适当的样品，产生了一系列合有1个VA族原子（N、P、As）或ⅢA族原子（B、Al）及13个以下碳原子的原子簇负离子。在实验记录的飞行时间质谱中，这些簇离子的信号强度均因其碳原子数的奇偶而发生交替变化．对实验结果的分析研究显示：这些簇离子均为直链构型．VA或ⅢA族原子位于链的一端，所有成簇原子的价键均得到满足．     

The effect of methyl group on the mechanical properties of hydrophobic association hydrogel

Hydrophobic association hydrogels were fabricated via micellar copolymerization of acrylamide and hydrophobic monomers lauryl (meth)acrylate (LA or LMA) in an aqueous solution of sodium dodecyl sulfate. The effect of methyl groups of hydrophobic monomers on the crosslinking network structure and mechanical behavior of the gels was investigated on the basis of rubber elastic theory. It was found that the LMA-gel exhibited higher effective crosslink density and elastic modulus. The methyl groups of hydrophobic monomers limited the flexibility of the methacrylate backbone in the association domain, which resulted in the increment of chains constraints. With the increase of stretch rate, the dissipated energy of LMA-gel increased more highly than that of LA-gel. In addition, the methyl group hindered the movement of polymer chains, leading to the lower recovery efficiency of dissipated energy for LMA-gel. In contract, the LA-gel exhibited a rapid response to external force, and possessed better elasticity and self-recovery property. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1505–1512     

Determination of nifedipine in dog plasma by high‐performance liquid chromatography with tandem mass spectrometric detection

Nifedipine is a dihydropyridine calcium channel blocker used widely in the management of hypertension and other cardiovascular disorders. In this work, a simple, rapid and sensitive liquid chromatography/tandem mass spectrometry method was developed and validated to determine nifedipine in dog plasma using nimodipine as the internal standard. Chromatographic separation was carried out on a C₈ column. The mobile phase consisted of a mixture of acetonitrile, water and formic acid (60:40:0.2, v/v/v) at a flow rate of 0.5 mL/min. Detection was performed on a triple quadrupole tandem mass spectrometer in selected reaction monitoring mode via an atmospheric pressure chemical ionization source. The method has a lower limit of quantification of 0.20 ng/mL with consumption of plasma as low as 0.05 mL. The linear calibration curves were obtained in the concentration range of 0.20–50.0 ng/mL (r = 0.9948). The recoveries of the liquid extraction method were 74.5–84.1%. Intra‐day and inter‐day precisions were 4.1–8.8 and 6.7–7.4%, respectively. The quantification was not interfered with by other plasma components and the method was applied to determine nifedipine in plasma after a single oral administration of two controlled‐release nifedipine tablets to beagle dogs. Copyright © 2013 John Wiley & Sons, Ltd.     

Flocking and asymptotic velocity of the Cucker–Smale model with processing delay

The processing delay is incorporated into the influence function of the well-known Cucker–Smale model for self-organized systems with multiple agents. Both symmetric and non-symmetric pairwise influence functions are considered, and a Lyapunov functional approach is developed to establish the existence of flocking solutions for the proposed delayed Cucker–Smale model. An analytic formula is given to calculate the asymptotic flocking velocity in terms of model parameters and the variation of the position during the initial time interval.