PI/TiO2纳米复合膜的H2/CH4和H2/N2分离性能

以可溶性聚酰亚胺为基质 ,经乙酸修饰后的钛酸丁酯为TiO2 溶胶前体 ,NMP为共溶剂 ,采用溶胶凝胶法可制得PI/TiO2 纳米复合膜。采用XPS、TEM和气体透气性能测试等手段 ,对复合膜的结构和H2 分离性能进行了表征。结果表明 ,复合膜中钛酸丁酯已转化为TiO2 ,PI与TiO2 两相结合完好。TiO2 以颗粒状均匀分布在PI基质中 ,其颗粒粒径约为 1 0nm。复合膜的H2 ,N2 和CH4 透气系数随着TiO2 含量的增加而明显增加。当TiO2 含量为2 2 3 %时 ,对H2 的透气系数为 1 4 .1Barrer,对H2 /N2 和H2 /CH4 的分离系数分别为 1 87.5和 1 4 3 .2 ,因此 ,该复合膜是一种较为理想的H2 分离和回收膜材料     

Asymptotic Approximations of Jacobi Polynomials and Their Zeros with Error Bounds

IntroductionUniform asymptotic expansions and error boundsof the (α,β>- 1 ) two- term approximations of theJacobi polynomials P(α,β)n ( cosθ) were obtained[1] .Their result wassin θ2α cosθ2βP(α,β)n ( cosθ) =Γ( n +α + 1 )n!θsinθ1/ 2 Jα( Nθ)Nα +θB0 (θ) Jα+1( Nθ)Nα+1+σ2 ,|σ2 |≤ E2 θ2 +αN -2 ,　 0≤θ≤ π2 ,where E2 is a construct.Baratella and Gatteschiused the first two terms of this expansion[2 ] toconstructa more accurate one- term approximation:x(θ)x′(θ)…     

Oxidative Treatment of Some Reactive Dyes by Fenton Reagent

Nine kinds of reactive dye solutions: Reactive K-2RL, H-E2R, X-6B1Y, HE-4G, X-3B, K-2R,H-E7B, X-4RN and S-F3B were treated by usingFenton reagent. While the concentration of dye is 400mg/L, the FeSO_4 dosage 100-180 mg/L, H_2O_2 240～540 mg/L, that is the stoichiometric numbers of Fe~(2+)and H_2O_2. are between 1: 9～1: 12, pH=3, reaction     

Quantitative Analysis on Postponement Strategies of Decoupling Points in Mass Customization

The key to mass customizing effectively is postponingthe deco upling point of customer order in the supplynetwork. This paper focused on quantitative analysison postponement strategies of multiple decouplingpoints in mass customization to improve operating     

Computer Data Processing of the Hydrogen Peroxide Decomposition Reaction

Two methods of computer data processing, linear fitting and nonlinear fitting, are applied to compute the rate constant for hydrogen peroxide decomposition reaction. The results indicate that not only the new methods work with no necessity to measure the final oxygen volume, but also the fitting errors decrease evidently.     

Effect of Carboxymethyl Starch as Stabilizer for Increasing the Stability of Warp Sizing Pastes

The influences of carboxymethyl starch used as stabilizer upon the stability of native cornstarch-polyvinyl alcohol blend pastes for warp sizing have been investigated. The effect of the modified starch on the paste stability was evaluated in terms of the initial demixing time and the volume percentage of separated starch. The carboxymethyl starch with a series of different degrees of substitution was prepared in ethanol dispersion by varying the amount of monochloroacetic acid reacted with refined native cornstarch. The paste stability strongly depends on the modification extent and amount of carboxymethyl starch used, and on native starch content in the paste. Increase in the modification extent and/or the amount of the modified starch effectively retards the phase separation and reduces the separation extent of native cornstarch-polyvinyl alcohol blend pastes. Moreover, the mechanism and favorable modification extent of carboxymethyl starch for enhancing paste stability are also investigated and disc     

Ratio K: a New Way of Metering and Evaluating the Risk and Return of Stock Investment

Although widely used, both the Markowitz model and VAR (Value at Risk) model have some limitations in evaluating the risk and return of stock investment. By the analysis of the conceptions of risk and return, together with the three hypotheses of technological analysis, a novelty model of metering and evaluating the risk and return of stock investment is established. The major indicator of this model , risk-return ratio K, combines the characteristic indicators of risk and return. Regardless of the form of the risk-return probability density functions, this indicator K can always reflect the risk-return performances of the invested stocks clearly and accurately. How to use the model to make optimum investment and how to make portfolio combined with clustering analysis is also explained.     

Structural Changes of Polyethylene Terephthalate Fibers Grafted by Acrylamide

A group of grafted PET fibers with different graft yield are formed by grafting acrylamide onto the PET main chains. The structure of grafted fibers are studied by scanning electronic microscope ( SEM ), infra-red spectrophotometer ( IR ), and differential scanning calorimetry(DSC). At the same time, the moisture regain, dyeability, strength, and elongation at break of the samples are measured and their relations with structural changes are discussed. Compared with ungrafted fiber, shape of the fiber cross-section, IR characteristic absorption peaks, and melting behavior of the grafted fibers have been changed, causing the fiber dyeability and moisture regain to be increased, and mechanical properties to be changed.     

Research on Precision Assembly Robot''''s Joint Torque Control Based on Current Measurement

A set of new current sensing device is used to realize joint torque control based on current measurement in a precision assembly robot's third joint. The output torque's model of the joint's brushless DC motor is founded. Disturbance factors and the compensated effect of the torque's closed loop based on current measurement are analyzed. Related simulations and experiments show that the system has good current tracking and anti-disturbances performance, which improve the force control performance of the robot in assembly.