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991.
In this paper, the author gives the discrete criteria and J\o rgensen inequalities of subgroups for the special linear group on $\overline{\mathrm{F}}((t))$ in two and higher dimensions.  相似文献   
992.
The focus of this work is the preparation of aramid nanofibers via electrospinning technology and the study of their adsorption properties. In this article, aramid nanofibers were prepared by electrospinning aramid fibers solution with the addition of lithium chloride (LiCl). It showed a good adsorption capacity when methylene blue (MB) was used as the model target. There were much larger adsorption amounts and faster kinetics of uptaking target species of electrospun aramid nanofibers to MB than that of electrospun polyethersulfone (PES) nanofibers. Compared with activated carbon, aramid nanofibers also have a much faster adsorption rate to MB. Aramid nanofibers were subsequently used to effectively remove endocrine disruptors such as bisphenol A (BPA), phenol (Phe), and p‐hydroquinone (BPhe) from their aqueous solutions. Additionally, molecule imprinted technology enhances aramid nanofibers with much higher adsorption amounts and special adsorption property for endocrine disruptors. These results showed that aramid nanofibers have the potential to be used in environmental applications. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012  相似文献   
993.
CuCr2O4 spinel powder with high quality black hue, investigated as solar-absorbing pigment for spectrally selective paint, was synthesized by an environmental friendly sol–gel combustion process using citric acid as the fuel and metal nitrates as oxidizers. Single-phase CuCr2O4 spinel crystals were obtained after heat treatment of the as-burnt powder at a low temperature (600 °C) and the average crystallite size of the CuCr2O4 powders increased with the calcining temperature. Morphological analysis of powders calcined at various temperatures was done by field emission scanning electron microscopy. CuCr2O4 powder calcined at 700 °C was chosen as pigment to fabricate thickness sensitive spectrally selective paint coatings by simple spray-coating technique. For the sake of comparison, the as-burnt powder composed of mixed metal oxides (i.e., CuO and Cr2O3) was also used as pigment. The results reveal that the spinel CuCr2O4 based paint coatings exhibit much higher spectral selectivity (α s = 0.88–0.91, ε 100 = 0.27–0.35) which is depending on the coating thicknesses than that of coatings using as-burnt powder as pigment (α s = 0.83–0.88, ε 100 = 0.60–0.66). The CuCr2O4-based paint coatings showed no visible degradation after 600 h of condensation test and the performance criterion value is 0.04, indicating that the coatings have excellent long term stability.  相似文献   
994.
995.
The effects of pH,contact time and natural organic ligands on radionuclide Eu(Ⅲ) adsorption and mechanism on titanate nanotubes(TNTs) are studied by a combination of batch and extended X-ray absorption fine structure(EXAFS) techniques.Macroscopic measurements show that the adsorption is ionic strength dependent at pH < 6.0,but ionic strength independent at pH > 6.0.The presence of humic acid(HA) /fulvic acid(FA) increases Eu(Ⅲ) adsorption on TNTs at low pH,but reduces Eu(Ⅲ) adsorption at high pH.The results of EXAFS analysis indicate that Eu(Ⅲ) adsorption on TNTs is dominated by outer-sphere surface complexation at pH < 6.0,whereas by inner-sphere surface complexation at pH > 6.0.At pH < 6.0,Eu(Ⅲ) consists of ~ 9 O atoms at REu?O ≈ 2.40  in the first coordination sphere,and a decrease in NEu-O with increasing pH indicates the introduction of more asymmetry in the first sphere of adsorbed Eu(Ⅲ).At long contact time or high pH values,the Eu(Ⅲ) consists of ~2 Eu at REu-Eu ≈ 3.60  and ~ 1 Ti at REu-Ti ≈ 4.40 ,indicating the formation of inner-sphere surface complexation,surface precipitation or surface polymers.Surface adsorbed HA/FA on TNTs modifies the species of adsorbed Eu(Ⅲ) as well as the local atomic structures of adsorbed Eu(Ⅲ) on HA/FA-TNT hybrids.Adsorbed Eu(Ⅲ) on HA/FA-TNT hybrids forms both ligand-bridging ternary surface complexes(Eu-HA/FA-TNTs) as well as surface complexes in which Eu(Ⅲ) remains directly bound to TNT surface hydroxyl groups(i.e.,binary Eu-TNTs or Eu-bridging ternary surface complexes(HA/FA-Eu-TNTs)).The findings in this work are important to describe Eu(Ⅲ) interaction with nanomaterials at molecular level and will help to improve the understanding of Eu(Ⅲ) physicochemical behavior in the natural environment.  相似文献   
996.
997.
998.
The present paper investigates the convergence of the Galerkin method for the dynamic response of an elastic beam resting on a nonlinear foundation with viscous damping subjected to a moving concentrated load. It also studies the effect of different boundary conditions and span length on the convergence and dynamic response. A train–track or vehicle–pavement system is modeled as a force moving along a finite length Euler–Bernoulli beam on a nonlinear foundation. Nonlinear foundation is assumed to be cubic. The Galerkin method is utilized in order to discretize the nonlinear partial differential governing equation of the forced vibration. The dynamic response of the beam is obtained via the fourth-order Runge–Kutta method. Three types of the conventional boundary conditions are investigated. The railway tracks on stiff soil foundation running the train and the asphalt pavement on soft soil foundation moving the vehicle are treated as examples. The dependence of the convergence of the Galerkin method on boundary conditions, span length and other system parameters are studied.  相似文献   
999.
Based on analysis on properties of quantum linear superposition, to overcome the complexity of existing quantum associative memory which was proposed by Ventura, a new storage method for multiply patterns is proposed in this paper by constructing the quantum array with the binary decision diagrams. Also, the adoption of the nonlinear search algorithm increases the pattern recalling speed of this model which has multiply patterns to O( log22n -t ) = O( n - t )O( {\log_{2}}^{2^{n -t}} ) = O( n - t ) time complexity, where n is the number of quantum bit and t is the quantum information of the t quantum bit. Results of case analysis show that the associative neural network model proposed in this paper based on quantum learning is much better and optimized than other researchers’ counterparts both in terms of avoiding the additional qubits or extraordinary initial operators, storing pattern and improving the recalling speed.  相似文献   
1000.
Xing Yang  Xiao-Li Hao  Gang Zhao 《Optik》2012,123(16):1486-1491
License plate location (LPL) is the key part of automatic license plate recognition (LPR) system that plays an important role in many applications and a number of LPL methods based on color information have been proposed. However, some problems, such as country specific, similar color interference, lighting variation sensitive, time consuming, processing only one kind of LP with same color combination a time and omitting the case of more than one combinations in a LP, should be solved further. In this study, a color-based LPL method that consists of three modules: color edge extraction, denoising and searching, is proposed. Color edge extraction, the kernel of the proposed, is designed by color-discrete characteristics of license plates in the trichromatic wavebands. In the experiment, 1384 images taken from natural scenes in China and other 104 countries or regions are employed. Of which, 74 have been failed to locate the license plates. The success rate and average execution time are 94.7% and 57 ms, respectively.  相似文献   
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