铜浮选专家控制系统设计与应用

针对国内某选矿厂铜浮选工艺泡沫速率不稳定,精矿品位波动大,回收率不理想等特点,设计了一套浮选专家控制系统,该系统结合泡沫影像分析技术,在线品位分析技术,PID控制与模糊逻辑控制技术。系统架构简明合理,逻辑层次清晰有效,投入运行一段时间后,在不同原矿品位前提下,都能实现稳定泡沫速率,减少精矿品位波动,提高回收率等指标优化,同时药剂添加量也有明显减少。这表明该系统运行效果良好,值得应用推广。     

Mechanical properties of epoxy networks based on DGEBA and aliphatic amines

The mechanical properties of epoxy networks based on diglycidyl ether of bisphenol A epoxy resin cured with various linear aliphatic amines, such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and cyclic amines such as 1‐(2‐aminoethyl)piperazine and isophorone diamine, were studied. General characteristics such as T_g, density, and packing density, were determined and related to the structure and funcionality of the curing agent. Dynamic mechanical spectra were used to study both the α and β relaxations. Tensile and the flexural tests were used to determine the Young's and flexural modulus, and fracture strength all in the glassy state. Furthermore, linear elastic fracture mechanics was used to determine K_IC. As a rule, isophorone diamine network presented the higher tensile and flexure modulus while 1‐(2‐aminoethyl)piperazine gave the highest toughness properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

The synergistic performance of multiwalled carbon nanotubes and sepiolite nanoclays as flame retardants for unsaturated polyester

The synergistic effect on the thermal decomposition and heat release rate (HRR) in particular the peak heat release rate (PHRR) of unsaturated polyester (UP) resin blended with multiwalled carbon nanotubes (MWNTs) and sepiolite nanoclay was investigated using thermal gravimetric analysis (TGA), pyrolysis combustion flow calorimetery (PCFC) and the cone calorimetery. Initial microcalorimeter findings established a synergistic effect for ternary system comprising a 10:0.5 wt% mixture of sepiolite:MWNT, respectively, which resulted in a 40% reduction in heat release capacity (HRC). This result was also confirmed within the well‐established cone calorimeter by a 50% reduction in PHRR in contrast to unfilled UP. The mechanism behind this reduction is thought to be due to the bridging of the MWNTs between the sepiolite clay needles, creating a tight protective surface layer that reduces the MLR. TGA also confirmed the advantage of such a ternary system through a 36^°C shift in the onset decomposition temperature and an 11% increase in residual char. Copyright © 2010 John Wiley & Sons, Ltd.     

Single-frame super-resolution in remote sensing: a practical overview

Image acquisition technology is improving very fast from a performance point of view. However, there are physical restrictions that can only be solved using software processing strategies. This is particularly true in the case of super resolution (SR) methodologies. SR techniques have found a fertile application field in airborne and space optical acquisition platforms. Single-frame SR methods may be advantageous for some remote-sensing platforms and acquisition time conditions. The contributions of this article are basically two: (1) to present an overview of single-frame SR methods, making a comparative analysis of their performance in different and challenging remote-sensing scenarios, and (2) to propose a new single-frame SR taxonomy, and a common validation strategy. Finally, we should emphasize that, on the one hand, this is the first time, to the best of our knowledge, that such a review and analysis of single SR methods is made in the framework of remote sensing, and, on the other hand, that the new single-frame SR taxonomy is aimed at shedding some light when classifying some types of single-frame SR methods.     

Effective reinforcement of carbon nanotubes in polypropylene matrices

This study describes an attempt to mechanically reinforce polypropylene (PP) using multi‐wall carbon nanotubes (MWNTs) through a melt compounding process followed by hot‐pressing and solid state drawing. The effect of a high density polyethylene (HDPE) coating on MWNTs and melt flow index (MFI) of PP on the dispersion of MWNTs and composite properties are studied by means of mechanical tests, transmission electron microscopy (TEM), scanning electron microscope (SEM), differential scanning calorimetry (DSC), and wide angle x‐ray diffraction (WAXD). Highly orientated composite tapes are prepared to fully utilize the properties of MWNTs in uniaxial direction. Highly aligned MWNTs are shown by SEM, while highly oriented polymer chains are characterized by WAXD. Composite theory is used to analysis the results and indicate that effective reinforcement of PP by MWNTs is highest at relatively low filler content and draw ratios. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Rigorous and efficient full-wave analysis of trapezoidal patchantennas

A rigorous full-wave analysis in the spectral domain for trapezoidal patch antennas is presented. Particularly, a new set of entire domain basis functions for an efficient implementation of the method of moments (MoM) is carried out by properly imposing the boundary conditions. The simulated results obtained through the presented method are compared to the measurements showing a good agreement. Finally, a parametric analysis of the main antenna features (matching, radiation pattern, cross-polarization levels) is also carried out     

Different strategies to recover the activity of monomeric triosephosphate isomerase by directed evolution

A monomeric version of triosephosphate isomerase from Trypanosomabrucei, MonoTIM, has very low activity, and the same is truefor all of the additional monomeric variants so far constructed.Here, we subjected MonoTIM to directed evolution schemes toachieve an activity improvement. The construction of a suitablestrain for genetic selection provided an effective way to obtainactive catalysts from a diverse population of protein variants.We used this tool to identify active mutants from two differentstrategies of mutagenesis: random mutagenesis of the whole geneand randomization of loop 2. Both strategies converged in theisolation of mutations Ala43 to Pro and Thr44 to either Alaor Ser, when randomizing the entire gene or to Arg in the caseof randomization of loop 2. The kinetic characterization ofthe two more active mutants showed an increase of 11-fold ink_cat and a reduction of 4-fold in K_m for both of them, demonstratingthe sensitivity of the selection method. A small differencein growth rate is observed when both mutant genes are compared,which seems to be attributable to a difference in solubilityof the expressed proteins.     

Influence of chemical structure of hardener on mechanical and adhesive properties of epoxy polymers

The mechanical and adhesive properties of epoxy formulations based on diglycidyl ether of bisphenol A cured with various aliphatic amines were evaluated in the glass state. Impact and uniaxial compression tests were used to determine the impact energy, elastic modulus and yield stress, respectively. The adhesion tests were carried out in steel–steel joints using single‐lap shear, T‐peel, and impact adhesive joints geometry. The better mechanical and adhesive behavior of the networks is obtained when exists high flexibility of chain between crosslink and/or high elastic modulus. The 1‐(2‐aminoethyl)piperazine epoxy network presents the best adhesive properties, high flexibility, and the largest impact energy. However, it possesses low elastic modulus and yield stress. Also, exhibits increases in peel strength and impact energy while reductions in lap shear strength. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Extended method of line procedure for the analysis of microwave components with bianisotropic inhomogeneous media

Method of line (MoL) procedure is very useful in the analysis of radiative and transmissive microwave components, but its standard version does not allow for the study of elements with complex substrates. In this work, we first show that components integrated into materials exhibiting the magneto-electric effect (biisotropic and general bianisotropic media) cannot be analyzed following a standard MoL algorithm. Next, we derive an extended MoL numerical tool, which allows for the analysis of components in the presence of any linear medium (even inhomogeneous, bianisotropic and lossy). Such an extension is based on the generalization of the transmission-line equations for a general linear medium, which, in the case in point, are not necessarily decoupled. Furthermore, we present the full coincidence of this new method with the standard MoL in the case of simpler media (i.e., not exhibiting the magneto-electric effect) and, finally, we show some numerical results, obtained analyzing microwave antennas and resonators with bianisotropic and chiral substrates.