树脂交换-比浊法测定混碳及料液中的硫酸根

为消除稀土离子颜色以及水解对比浊法测定混合碳酸轻稀土及氯化稀土料液中的硫酸根的影响,采用在酸性条件下,稀土离子与TYPE型阳离子交换树脂进行交换,溶液中的硫酸根与Ba~(2+)反应生成Ba SO_4,在稳定剂的存在下,比浊测定硫酸根的含量。分别讨论了树脂的交换能力、空白的影响、Ba SO_4的凝聚时间等研究内容。通过精密度和准确度数据,确定了试验的最优条件,w(SO~(2-)_4)测定范围为0.01%~1.5%,RSD为2.3%~15.4%。     

Influence of EDTA on Demineralization Rate of Dentine： Calcification Treatment in Root Canal Therapy

The aim of this study was to investigate the influence of ethylenediaminetetraacetic acid （EDTA） irrigation on demineralization rate of dentine located in the apical third of root canal walls. Teeth were divided into A and B two groups. In group A, all of the teeth was irrigated with EDTA and NaOCI （sodium hypochlorite）, followed by cutting the apical third into slices longitudinally to examine the influence of EDTA on different portions of apical third of root canal. In group B, the apical third of a tooth was firstly cut into slices longitudinally, followed by coating the root canal walls with EDTA to in-situ observe the demineralization of dentine with different time. It was found that the influence of EDTA on root-canal was gradually increased from the apical to the upper end of the apical third for group A. In addition, the demineralization rate of dentine was remarkable in the first 25 min for group B. The diffusion of EDTA into root dentine would lead to potential damage to the dentine. Furthermore, demineralization rate curve was calculated.     

A3M: an agent architecture for automated manufacturing

This paper proposes a software architecture based on mobile agents for distributed process control applications. A set of agents is employed to handle, in a single manufacturing cell, automatic assignment of control tasks to controllers, monitoring of cell functionalities and dynamic cell reconfiguration. The agents operate in a two‐layered structure: at the highest level, the planning agents analyse the inputs of the system designer and automatically create the field agents, which operate at the lowest level and embed the control tasks to be executed. Field agents, which are mobile, are able to reach autonomously the controllers of the cell, in order to perform the control activity there. Exploiting the mobility enables a field agent to change its running device when the variation of the design parameters or a system fault requires a new task distribution. A load‐balancing algorithm is introduced, with the objective of assigning each field agent to a controller of the manufacturing cell in order to fairly distribute the computation load. The algorithm uses a branch‐and‐bound technique to explore all possible solutions and applies two heuristics to throw away non‐feasible solutions and select the best branch to analyse. The algorithm is designed to run on‐line in order to allow a fast task redistribution when a fault condition occurs in the process control environment. Copyright © 2008 John Wiley & Sons, Ltd.     

Peptide fingerprint of high quality Campania white wines by MALDI-TOF mass spectrometry

Food traceability is essential to preserve the identity of unique quality traits against frauds or commercial disputes. Therefore, there is a growing demand of new traceability systems for the collection of information related to units/batches of food ingredients and products.     

油田罐区消防泵控制方案设计

本文针对某海外油田罐区消防系统实际状况，在满足工艺要求及现场情况的前提下，提出了一种解决消防泵控制方案，有效的提高了油田罐区火灾的应急处理能力。详细介绍了消防泵的控制方法，为类似油田消防泵控制系统的设计提供了借鉴和参考。     

Mechanical properties of proton-conducting sulfonated aromatic polymer membranes: Stress-strain tests and dynamical analysis

The mechanical properties of sulfonated aromatic polymers (SAPs: SPEEK and SPPSU) are studied by tensile stress-strain tests and dynamic mechanical analysis (DMA). The elastic moduli are generally above 1 GPa with tensile strength between 25 and 80 MPa and elongation at rupture between 7 and 50%. These properties are consistent with polymers below their glass transition temperature. The glass transition and elastic moduli are strongly increased by thermal treatments of the SAP membranes, due to formation of cross-links between macromolecules. The cross-linking is observed “in situ” during DMA experiments on thermally untreated SPPSU. These data show that previously neglected SAPs might become very interesting PEM fuel cell membranes, if previously thermally treated.     

Kinetic and mass transfer in the hydrogenation of polyunsaturated organic compounds in the presence of supported Pd catalysts

The hydrogenation of 1,5-cyclo-octadiene has been studied on well-defined Pd catalysts. The reaction is affected by internal diffusion of hydrogen into the catalyst particles. Despite this limitation, the reaction orders of the reactants have been determined. All the performed kinetic runs have been simulated and the kinetic and mass-transfer parameters giving the best fit of experimental data have been evaluated. The reaction occurs in two steps, in the first, a conjugate diene (1,3-cyclo-octene) is formed via isomerization, then, hydrogenation occurs quickly forming the monoene. The hydrogenation of the obtained cyclo-octene is relatively slow and strongly inhibited by the presence of the cyclo-octadiene. This last reaction has, therefore, been used for comparing the activities of different palladium catalysts showing an exponential behaviour of the reaction rate with the metal dispersion.     

Light olefins dimerization to high quality gasoline components

New attractive technologies can be designed in the field of light olefins dimerization (C₃–C₅) in order to obtain products useful as gasoline blending components; the technologies are characterized both by low investment costs and by high product quality. Isobutene dimerization is a powerful alternative to MTBE production whenever the use of the latter will be forbidden in gasoline. Also the dimerization of iso-amylenes and propylene, when properly designed, can give products (both the olefins and the corresponding hydrogenated derivatives) characterized by very high octane numbers. More in general all these technologies can help to debottleneck the FCC downstream when enhanced olefins production is achieved by means of new FCC catalysts and processes.     

Electro-elastic fields of piezoelectric materials with an elliptic hole under uniform internal shearing forces

The existing investigations on piezoelectric materials containing an elliptic hole mainly focus on remote uniform tensile loads. In order to have a better understanding of the fracture behavior of piezoelectric materials under different loading conditions, theoretical and numerical solutions are presented for an elliptic hole in transversely isotropic piezoelectric materials subjected to uniform internal shearing forces based on the complex potential approach. By solving ten variable linear equations, the analytical solutions inside and outside the hole satisfying the permeable electric boundary conditions are obtained. Taking PZT-4 ceramic into consideration, numerical results of electro-elastic fields along the edge of the hole and axes, and the electric displacements in the hole are presented. Comparison with stresses in transverse isotropic elastic materials shows that the hoop stress at the ends of major axis in two kinds of material equals zero for the various ratios of major to minor axis lengths; If the ratio is greater than 1, the hoop stress in piezoelectric materials is smaller than that in elastic materials, and if the ratio is smaller than 1, the hoop stress in piezoelectric materials is greater than that in elastic materials; When it is a circle hole, the shearing stress in two materials along axes is the same. The distribution of electric displacement components shows that the vertical electric displacement in the hole and along axes in the material is always zero though under the permeable electric boundary condition; The horizontal and vertical electric displacement components along the edge of the hole are symmetrical and antisymmetrical about horizontal axis, respectively. The stress and electric displacement distribution tends to zero at distances far from the elliptical hole, which conforms to the conclusion usually made on the basis of Saint-Venant’s principle. Unlike the existing work, uniform shearing forces acting on the edge of the hole, and the distribution of electro-elastic fields