EPVC－Ⅱ型旋风管流场的实验研究

本文用五孔球探针测量了ＥＰＶＣ一Ⅱ型旋风管的流场，研究了分离空间高度、排尘结构形式对流场的影响，发现了排尘口处的旋流屏蔽现象，确定了适宜的结构尺寸并回归得到切向速度的计算公式。     

二氧化碳催化加氢研究进展

介绍了近年来由 CO2 催化加氢制取甲醇、烃类、醛类、甲酸和二甲醚等反应的研究进展     

Morphologies and microstructures of tree-like carbon produced at different reaction conditions in a CVD process

Centimeter-size multi-branched tree-like carbon structures have been generated by the catalytic chemical vapor deposition of toluene using ferrocene as the catalyst precursor and investigated by means of SEM, TEM, and EDX. It is found that a temperature of 1000-1200 °C and a carrier gas flow rate of 1000-2500 ml/min are necessary for the generation of the carbon trees. Their morphologies and microstructures change greatly with the changing reaction conditions. The fractal dimensions of the trees are calculated to quantitatively investigate the influence of different reaction temperatures on the morphologies.     

淀粉化工新进展

本文综述了国内外淀粉化工的发展概况，从氨基酸和有机酸、螯合物、羧甲基淀粉、淀粉塑料、淀粉基表面活性剂和淀粉粘合剂等６个方面评述了淀粉化工的新进展。提出以淀粉及水解产物、衍生物为原料，进行深度加工，开发一系列化工产品，是发展我国淀粉化工的重要途径之一。     

A numerical analysis of rate data for packed bed reactors in gas-solid reaction systems

A numerical solution of the pseudo-steady state governing equations on the basis of the Langmuir-Hinshelwood type rate equation was obtained by the approximate finite difference method in packed bed reactors for gas-solid reaction system. It was proved that the numerical method has good accuracy compared with the strict solution in the special case that the reaction rate can be represented by the first-order kinetics in terms of gaseous reactant and the effectiveness factor is unity druing the reaction. The numerical method is proposed to predict the transient of exit-gas compositions of a packed bed reactor used for gas-solid reaction systems. The exit-gas composition can be predicted from the conversion data of a single particle with varying reaction time. The present method can be easily applied to the systems involving adsorptive gaseous reactants and complex reaction behavior with structural changes of particles.     

Effect of adsorptive gaseous reactant on non-isothermal behavior for gas-solid reactions

The effect of adsorptive species on non-isothermal gas-solid reactions is studied on the basis of Langmuir-Hinshelwood kinetics. The concept of an effectiveness factor provides good information to ascertain the effect of adsorptive species and the transition of the rate controlling regime, in connection with the parameters, generally used in the analysis of non-isothermal behavior. For highly exothermic reactions, the effectiveness factor-Thiele modulus curves with multiple solutions are presented with respect to the modified adsorption equilibrium constant. The variations of the rate-controlling regime by the effect of adsorptive species are also discussed.     

A new characterization procedure for aqufous solutions with unknown composition

A new characterization procedure for aqueous solutions with unknown composition was proposed based on the binomial distribution of TOC (total organic carbon) fraction in terms of a characterizing variable, the Freundlich coefficient, k, so that the solution in question can be described by a finite number of pseudo.species identified with a certain k value. The validity and computational accuracy of this procedure has been demonstrated by characterizing three sets of experimental data chosen from different sources. Predictions based on this procedure yielded acceptable results that agreed closely with experimental data.     

聚丙烯酸酯作为塑料化学镀镍预处理剂的研究

考察了采用聚丙烯酸酯作ABS塑料的表面处理剂的可行性。通过X射线电子能谱(XPS)、扫描电子显徽镜(SEM)和X射线能量色散分析仪(EDAX)分别研究了该豫处理的机理、镀层形貌和镀层表面镍磷的含量,并讨论了温度和pH值对镍磷在ABS表面沈积速率的影响。     

Diffusional interference in liquid phase counter-adsorptions

A surface diffusion mocel with diffusional interference has been presented for the analysis of multicomponent adsorption of phenols by activated carbon. Surface diffusion coefficients for multicomponent adsorptions were estimated from the relationship between. the surface diffusion coefficient of each species and the surface coverage. The diffusional interference coefficients, W_ij, was determined from experimental counter-adsorption data. The numerical values of W_ij were in the range of 0.4–0.9, which show that the introduction of diffusional interference is necessary to analyze multicomponent counter-adsorptions properly. The proposed model successfully simulates the behaviour of phenols-activated carbon system in a batch adsorber.     

On the complexity of role updating feasibility problem in RBAC

In Role Based Access Control (RBAC) systems, it is necessary and important to update the role–permission assignments in order to reflect the evolutions of the system transactions. However, role updating is generally complex and challenging, especially for large-scale RBAC systems. This is because the resulting state is usually expected to meet various requirements and constraints. In this paper, we focus on a fundamental problem of role updating in RBAC, which determines whether there exists a valid role–permission assignment, i.e., whether it can satisfy all the requirements of the role updating and without violating any role–capacity or permission–capacity constraint. We formally define such a problem as the Role Updating Feasibility Problem (RUFP), and study the computational complexity of RUFP in different subcases. Our results show that although several subcases are solvable in linear time, this problem is NP-complete in the general case.