Rheological behavior of associating ionic polymers based on diallylammonium salts containing single-, twin-, and triple-tailed hydrophobes

The cycloterpolymerizations of N,N-diallyl-(4-octyloxy)benzyl-, N,N-diallyl-(3,5-dioctyloxy)benzyl-, and N,N-diallyl-(3,4,5-trioctyloxy)benzyl-ammonium chloride (0-8 mol%) with hydrophilic monomer N,N-diallyl-N-carboethoxymethylammonium chloride and sulfur dioxide afforded a series of cationic polyelectrolytes (CPE). The CPEs were treated with HCl and NaOH to produce the corresponding pH-responsive cationic acid salts (CAS) and polybetaines (PB), anionic polyelectrolytes (APE) as well as polymers PB/APE containing various proportions of zwitterionic (PB) and anionic fractions (APE) in the polymer chain. Likewise, the cycloterpolymerizations of these single-, twin-, and triple-tailed hydrophobes (0-12 mol%) with hydrophilic monomer diallyldimethylammonium chloride and sulfur dioxide afforded a series of CPE in excellent yields. The polymers were characterized by different techniques including NMR and IR. The solution properties of the series of CPE were investigated by rheological techniques. The studied water soluble polymers showed different rheological behavior depending on their structure (hydrophobe type and content) as well as salinity and pH. The high shear thinning and the formation of networks at low shear would likely promote the use of such polymers in enhanced oil recovery applications.     

Effect of ionic conductivity of a PAN–PC–LiClO<Subscript>4</Subscript> solid polymeric electrolyte on the performance of a TiO<Subscript>2</Subscript> photoelectrochemical cell

A nanoparticle TiO₂ solid-state photoelectrochemical cell has been fabricated. The effect of ionic conductivity of a solid electrolyte of polyacrylonitrile (PAN)–propylene carbonate (PC)–lithium perchlorate (LiClO₄) on the performance of a photoelectrochemical cell of indium tin oxide (ITO)/TiO₂/PAN–PC–LiClO₄/graphite has been investigated. A nanoparticle TiO₂ film was deposited onto ITO-covered glass substrate by controlled hydrolysis technique. A solid electrolyte of PAN–LiClO₄ with PC plasticizer prepared by solution casting technique was used as a redox couple medium. The room temperature conductivity of the electrolyte was determined by AC impedance spectroscopy technique. A graphite electrode was prepared onto a glass slide by electron beam evaporation technique. The device shows a photovoltaic effect under illumination. The short-circuit current density, J _sc, and open-circuit voltage, V _oc, vary with the conductivity of the electrolyte. The highest J _sc of 2.82 μA cm⁻² and V _oc of 0.56 V were obtained at the conductivity of 4.2 × 10⁻⁴ Scm⁻¹ and at the intensity of 100 mW cm⁻².     

Fabrication of a nanoparticle TiO<Subscript>2</Subscript> photoelectrochemical cell utilizing a solid polymeric electrolyte of PAN–PC–LiClO<Subscript>4</Subscript>

A nanoparticle TiO₂ solid-state photoelectrochemical cell utilizing as a solid electrolyte of poly(acrylonitrile)–propylene–carbonate–lithium perchlorate (PAN–PC–LiClO₄) has been fabricated. The performance of the device has been tested in the dark and under illumination of 100-mW cm⁻² light. A nanoparticle TiO₂ film was deposited onto indium tin oxide-covered glass substrate by controlled hydrolysis technique assisted with spin-coating technique. The average grain size for the TiO₂ film is 76 nm. LiClO₄ salt was used as a redox couple. The room temperature conductivity of the electrolyte is 4.2 × 10⁻⁴ S cm⁻¹. A graphite electrode was prepared onto a glass slide by electron beam evaporation technique. The device shows the rectification property in the dark and shows the photovoltaic effect under illumination. The best J _sc and V _oc of the device were 2.82 μA cm⁻² and V _oc of 0.58 V, respectively, obtained at the conductivity of 4.2 × 10⁻⁴ S cm⁻¹ and intensity of 100 mW cm⁻². The J _sc was improved by about three times by introducing nanoparticle TiO₂ and by using a solid electrolyte of PAN–PC–LiClO₄ replacing PVC–PC–LiClO₄ in the device. The current transport mechanism of the cell is also presented in this paper.     

Interacting Entropy-Corrected New Agegraphic K-essence, Tachyon and Dilaton Scalar Field Models in?Non-flat Universe

We consider the new agegraphic dark energy model with the help of the quantum corrections to the entropy-area relation in the setup of loop quantum gravity. Employing this new form of dark energy so called entropy-corrected new agegraphic dark energy (ECNADE), we investigate the model of interacting dark energy and derive its equation of state (EoS). We study the correspondence between the K-essence, tachyon and dilaton scalar fields with the interacting (ECNADE)in the non-flat FRW universe. Moreover, we reconstruct the corresponding scalar potentials which describe the dynamics of the scalar field.     

CFD analysis of an oscillating wing at various reduced frequencies

The effect of various reduced frequencies has been examined for an oscillating aspect ratio 10 NACA 0015 wing. An unsteady, compressible three‐dimensional (3D) Navier–Stokes code based on Beam and Warming algorithm with the Baldwin–Lomax turbulence model has been used. The code is validated for the study against published experimental data. The 3D unsteady flow field is simulated for reduced frequency values of 0.1, 0.2 and 0.3 for a fixed mean angle of attack position and fixed amplitude. The type of motion is sinusoidal harmonic. The force coefficients, pressure distributions and flow visualization show that at the given conditions the flow remains attached to the wing surface even at high angles of attack with no clear separation or typical light‐to‐deep category of dynamic stall. Increased magnitude of hysteresis and higher gradients are seen at higher reduced frequencies. The 3D effects are even found at midspan locations. In addition, the rate of decrease in lift near the wing tips compared with the wing root is not much like in the static cases. Copyright © 2008 John Wiley & Sons, Ltd.     

Enzymatic glucose biosensor based on flower-shaped copper oxide nanostructures composed of thin nanosheets

Well-crystallized flower-shaped copper oxide nanostructures composed of thin nanosheets has been synthesized by simple low-temperature hydrothermal process and used to fabricate highly sensitive amperometric glucose biosensor which exhibited a high and reproducible sensitivity of 47.19 μA mM^?1 cm^?2, response time less than 5 s, linear dynamic range from 0.01 to 10.0 mM, correlation coefficient of R = 0.9986, and limit of detection (LOD), based on S/N ratio (S/N = 3) of 1.37 μM. This work opens a way to utilize simply-grown CuO nanostructures as an efficient electron mediator to fabricate efficient glucose biosensors.     

Neutron spectrum parameters in irradiation channels of the Nigeria Research Reactor-1 (NIRR-1) for the <Emphasis Type="Italic">k</Emphasis><Subscript>0</Subscript>-NAA standardization

Summary The first nuclear research reactor in Nigeria has been commissioned for neutron activation analysis and limited radioisotope production. In order to extend its utilization to include the k₀-standardization method, the following neutron spectrum parameters in inner and outer irradiation channels were determined by the “Cd-ratio for multi-monitor method”: the thermal-to-epithermal flux ratio, f, and the epithermal flux shape factor, α. Neutron spectrum parameters determined in the inner irradiation channel B2, are: α = -0.052±0.002 and f = 19.2±0.5. For the outer irradiation channel B4, the neutron spectrum parameters were found to be α = +0.029±0.003 and f = 48.3±3.3. The results are compared with the neutron spectrum parameters of other reactor facilities with similar core configuration such as the Slowpoke and Miniature Neutron Source Reactor facilities available in the literature.     

Non-catalytic growth of high aspect-ratio ZnO nanowires by thermal evaporation

High-density and high aspect-ratio ZnO nanowires were grown on Si(100) substrates by the thermal evaporation of metallic zinc powder without the use of metal catalysts or additives. The as-grown nanowires had diameters in the range of 60-100 nm with lengths 5-15 μm. Detailed structural characterization indicated that the obtained nanowires are single-crystalline with a perfect hexagonal facet and surfaces. The room temperature PL spectrum exhibited strong UV emission, affirming that the as-grown products have good optical properties. The possible growth mechanism for the formation of hexagonal-faceted and perfect surface ZnO nanowires is also discussed.     

英文维文人名机器翻译算法的研究与实现

本文提出了一种基于规则库的多层过滤进行机器翻译的算法.该算法实现了英文人名向维吾尔文人名的自动翻译.该算法不同于传统的英维人名翻译系统所采取的方法,不需要建立丰富、全面的两种语言人名对齐词库.本算法在对已翻译的大量实例进行统计并分析的基础上,找出了英文与维文人名翻译的三层规则并设计出了本算法.