The effects of metal ions loaded onto activated carbons on adsorption capability of dichloromethane/trichloromethane were investgated. Four kinds of metal ions loaded activated carbons were prepared by the impregnated...
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The effects of metal ions loaded onto activated carbons on adsorption capability of dichloromethane/trichloromethane were investgated. Four kinds of metal ions loaded activated carbons were prepared by the impregnated method. Breakthrough curves for dichloromethane/trichloromethane adsorption on modified activated carbons in a fixed bed were measured. The effects of metal ions loaded onto activated carbons on adsorption capability of dichloromethane/trichloromethane was discussed with the help of the hard soft acid base principle. The results showed that the adsorption capability of the modified activated carbons for dichloromethane/trichloromethane decreased in the order of Fe(III)-AC>Mg(II)-AC>Cu(II)-AC>AC>Ag(I)-AC. Based on the hard soft acid base principle, dichloromethane and trichloromethane are hard base. The loading of Fe3+, Mg2+ enhanced the interaction between dichloromethane/trichloromethane and the surfaces of modification activated carbons because Fe3+, Mg2+ are hard acid, and the loading of Ag+ weakened the interaction between dichloromethane/trichloromethane and the Ag (I)/AC surfaces because Ag+ is a soft acid.
Cascading failures often occur in congested networks such as the Internet. A cascading failure can be described as a three-phase process： generation, diffusion, and dissipation of the congestion. In this account, we ...
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Cascading failures often occur in congested networks such as the Internet. A cascading failure can be described as a three-phase process： generation, diffusion, and dissipation of the congestion. In this account, we present a function that represents the extent of congestion on a given node. This approach is different from existing fimctions based on betweenness centrality. By introducing the concept of ＇delay time＇, we designate an intergradation between permanent removal and nonremoval. We also construct an evaluation fimction of network efficiency, based on congestion, which measures the damage caused by cascading failures. Finally, we investigate the effects of network structure and size, delay time, processing ability and packet generation speed on congestion propagation. Also, we uncover the relationship between the cascade dynamics and some properties of the network such as structure and size.
The Fe-O films were deposited on pure iron substrates by immersion ion implantation and deposition (PIII&D) to improve the medical performance of stents. The microstructures and mechanical properties of the films ...
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The Fe-O films were deposited on pure iron substrates by immersion ion implantation and deposition (PIII&D) to improve the medical performance of stents. The microstructures and mechanical properties of the films were characterized with X-ray diffraction (XRD), glancing angle X-ray diffraction (GAXRD), and X-ray photoelectron spectroscopy (XPS) and conventional mechanical probes. The impact of film growth conditions on the films was studied and the corrosion characteristics of the Fe-O films were evaluated with the simulated body fluid (SBF). The results show that the oxygen flow rate strongly affects the phase structures of the Fe-O films and the interfacial adhesion. For instance, Fe-O forms at low oxygen flow rates;whereas at an increased oxygen flow rate, FeO phase changes into Fe3O4. phase. At an oxygen flow rate of 3.4 sccm, Fe-O films with high corrosion resistance and fairly strong interfacial adhesion can be grown on iron substrates. We suggest that Fe-O films coated stainless steel be a potential material for stent fabrication.
In this paper, a series of composites of Eu-Tb rare-earth complex/methacrylate-type polymer, namely EuxTb1-x (TTA)(Phen)-P(MMA-co-MAA) (x=1, 0.75, 0.5, 0.25, 0), were prepared with different ratios of Tb3+ by in-situ ...
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In this paper, a series of composites of Eu-Tb rare-earth complex/methacrylate-type polymer, namely EuxTb1-x (TTA)(Phen)-P(MMA-co-MAA) (x=1, 0.75, 0.5, 0.25, 0), were prepared with different ratios of Tb3+ by in-situ synthesis. The structure and microscopic morphology of EuxTb1-x (TTA)(Phen)-P(MMA-co-MAA) were characterized by FT-IR spectra and SEM images. The optical gap and photoluminescent properties were investigated by UV-vis absorption spectra and photoluminescent spectra. The results indicated that EuxTb1-x (TTA)(Phen)-P(MMA-co-MAA) could emit mostly characteristic fluorescence of europium ion and intense red fluorescence with peak wavelength at 613 nm under UV excitation at 365 nm. Photoluminescent intensity of them was found to be influenced with the content of MAA and Tb3+. It was demonstrated that EuxTb1-x (TTA)(Phen)-P(MMA-co-MAA) were excellent red photoluminescent composites of rare-earth complex/methacrylate-type polymer.
A new moving object segmentation approach based on the motion field extracted from H.264 compressed domain is proposed. The noisy motion vectors in the motion field are first removed by the vector median filtering. Th...
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A new moving object segmentation approach based on the motion field extracted from H.264 compressed domain is proposed. The noisy motion vectors in the motion field are first removed by the vector median filtering. Then the predicted motion fields reconstructed by backward estimation are used to accumulate the motion field. After that, global motion compensation is performed on the accumulated motion field with moving background. Finally the modified statistical region merging is exploited to segment the moving object based on magnitude, divergence and curl. Experimental results demonstrate that our approach is applied to the H. 264 video with static or moving background and the segmentation quality is good.
A novel optical fiber sensor model based on surface plasmon resonance phase modulation is presented. The theoretical model related to several resonance excitation parameters is established according to light waveguide...
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A novel optical fiber sensor model based on surface plasmon resonance phase modulation is presented. The theoretical model related to several resonance excitation parameters is established according to light waveguide theory and multi-layer reflection theory. The mechanism and characteristics of the phase modulation are studied. Simulation results indicate that with the increase of the incidence light wavelength, the refractive index of the fiber core and the absolute value of the dielectric constant real part of metal, the liquid refractive index measuring range corresponding to the phase change shifts towards the higher refractive index. With the increase of the incidence light angle and the void part of the metal, the sensitivity of phase modulation degrades gradually. Therefore, the liquid refractive index measuring range and the sensitivity can be adjusted by the selection of the resonance excitation parameter.
Three different kinds of lead-free piezoelectric ceramics, barium titanate (BT), sodium bismuth titanate (BNT), and KNbO3-NaNbO3(KNN), were fabricated and inlayed into polymethymethacrylic (PMMA) of denture base resin...
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Three different kinds of lead-free piezoelectric ceramics, barium titanate (BT), sodium bismuth titanate (BNT), and KNbO3-NaNbO3(KNN), were fabricated and inlayed into polymethymethacrylic (PMMA) of denture base resin. The structure of the piezoelectric ceramic specimen was measured by X-ray diffraction (XRD) technique. The bond strength of the lead-free piezoelectric ceramics with polymethymethacrylic was investigated, and the strength values was measured through adhesive shearing strength test. The results demonstrated that the adhesive shearing strength values of the three kinds of specimens showed statistic significance (PBNT>BT. These results show the favorable adhesive properties between the lead-free piezoelectric ceramics and polymethymethacrylic materials, which might provide a new strategy for the application of oral clinical treatment.
Mg-Al hydrotalcite nanocrystalline was synthesized by the liquid coprecipitation method and characterized by XRD, TEM and TG. The effects on the crystal from different reaction conditions, such as reaction temperature...
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Mg-Al hydrotalcite nanocrystalline was synthesized by the liquid coprecipitation method and characterized by XRD, TEM and TG. The effects on the crystal from different reaction conditions, such as reaction temperature, drying time and carbonate ion concentration, were investigated systematically. The samples were modified by silane coupling agent KH550, and then filled into polyether polyol to synthesize hydrotalcite/polyurethane nano-composites. The flame retardancy of hydrotalcite, in comparison to Al(OH)3, was studied. Results indicated that the higher reaction temperature, the bigger crystal size;the thermal decomposition performance of hydrotalcite is better after drying 5h;the crystal regularity improved with the increasing carbonate ion concentration. Moreover, it is found that the optimum dosage of silane coupling agent KH550 is 5%. Finally, the results of flame-retardant test showed that the flame retardancy of Mg-Al hydrotalcite is better than that of Al(OH)3.
Monitoring user's abnormal behaviors, which is an effective method to detect impersonation, is used for impersonation detection in insider threats. A model is built by using TAN-based Bayesian network to reflect t...
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Monitoring user's abnormal behaviors, which is an effective method to detect impersonation, is used for impersonation detection in insider threats. A model is built by using TAN-based Bayesian network to reflect the characteristics of user's behavior. When the deviation from the model is found, the system can determine the identity of the user. As a result, experiments show that the monitoring numbers of processes called by users can be very effective on detecting impersonation and can identify the identity of the attacker.
The support vector method was applied to classify rock quality, and the indexes often used in engineering such as rock quality designation, integrity coefficient, uniaxial saturated compressive strength, and friction ...
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The support vector method was applied to classify rock quality, and the indexes often used in engineering such as rock quality designation, integrity coefficient, uniaxial saturated compressive strength, and friction factor of structural planes were adopted as discriminant parameters. The radial basis kernel function was selected to train samples, the optimized model parameters were determined by cross-validation, and a model of rock quality ranks was established. In comparison with the existing multi-classification model based on support vector machine constructed by a one-against-all method, the multi-classification model constructed by the pairwise method proposed in this paper may obviously reduce the indivisible region, that is, extraordinarily improves the model accuracy. Applications of this model to engineering show that the result of this model agrees with that of engineering reconnaissance, indicating that the classification method of rock quality ranks is effective.
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