We have employed a full-relativistic version of an all-electron full-potential linearized-augmented plane-wave method in the local density approximation to investigate the electronic structure of nanolaminate Zr2AlX (X=C and N). The Zr 4d electrons are treated as valence electrons. We have investigated the lattice parameters, bulk moduli, band structures, total and partial densities of states and charge densities. It is demonstrated that the strength and electrical transport properties in these materials are principally governed by the metallic planes. 相似文献
In this study, a more general version of F-expansion method is proposed. With this offered method, more than one Jacobi elliptic functions are located in the solution function. We seek analytical solutions of the space-time fractional cubic Schrodinger equation by use of the new type of F-expansion method. Consequently, multifarious exact analytical solutions consisting of single, double, and multiple combined Jacobi elliptic functions solutions are acquired. 相似文献
One of the important stages in supply chain management which regards all the activities from the purchasing of raw material to final delivery of the product is the supplier selection process. Since it is the first stage of the supply chain management, it is a critical process affecting the consecutive stages. It is simply desired to select the best supplier for a specific product. But since there are a lot of criteria and alternatives to be considered, numerous decision making models have been proposed to provide a solution to this problem. Within this study, an integrated approach including fuzzy Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and a mixed integer linear programming model is developed to select the best supplier in a multi-item/multi-supplier environment. The importance value of each supplier with respect to each product is obtained via fuzzy TOPSIS in the first stage. Then in the second stage, these values are used as an input in the mathematical model which determines the suppliers and the quantities of products to be provided from the related suppliers. So as to validate the proposed methodology, an application is performed in air filter sector. 相似文献
The aim of this study was to investigate the effect of three saponin-containing plant species extracts (Aesculuc hippocastanum L. seed extract [AHE], Medicago sativa L. extract [MSE] and Spinacia oleracea L. extract [SOE]) on lipid peroxidation and on antioxidant systems in rats exposed to X-rays (XR). The rats were divided into three categories. The first category served as controls and received only a standard diet. The second category served as the radiation group and received 5 and 10 Gy XR dose. The third category (XR+extract-treated) received plant extracts (25.0 or 50.0 mg kg(-1) live weight) and 5 or 10 Gy XR dose. Blood samples were analyzed for their content of malondialdehyde (MDA), reduced glutathione (GSH), plasma vitamin C, beta-carotene and retinol. In animals receiving XR, the plasma MDA (P < 0.001) value significantly increased but the level of GSH (P < 0.01), vitamin C (P < 0.001), retinol and beta-carotene (P < 0.001) decreased significantly with increasing XR doses. In the XR+extract-treated groups, the concentrations of MDA increased significantly with increasing radiation but their concentrations decreased significantly with increasing extract concentrations. Plasma concentrations of GSH, beta-carotene, retinol and vitamin C in XR+extract-treated groups decreased significantly with increasing XR dose but their concentrations increased with increasing extract doses. Further, comparison of blood samples of XR+extract-treated groups with those from the control group showed that GSH, beta-carotene, retinol and vitamin C values increased significantly but that MDA values decreased significantly. The results showed that all extracts have enhanced the antioxidant status and decreased the incidence of free radical-induced lipid peroxidation in blood samples of rats exposed to XR. However, the antioxidant effect of AHE-administered animals was more effective than that of MSE- and SOE-administered whole-body XR rats. We conclude that the supplementation with saponin-containing extracts may serve to reinforce the antioxidant systems, thus having protective effect against cell damage by XR. 相似文献
A new sandwich-tpype dilutetium tetraphthalocyanine 4 has been synthesized by the reaction of dimeric lutetium(III) phthalocyanine 3 with two equiv. of dilithium octakishexylthiophthalocyanine in amyl alcohol. Compound 3 was prepared from 4',5',4",5"-tetraiminoisoindoline(1,4,7,10-tetrathia-12-crown-4) 1, 4,5-bis(hexylthio)-1,2-diiminoisoindoline and lutetium acetate in amyl alcohol. Compounds 3 and 4 were characterized by elemental analysis, UV/visible, IR, (1)H NMR and ESR spectroscopy. The electrochemical and electrochromic properties of 3 and 4 have been examined by cyclic voltammetry. Both 3 and 4 displayed well-defined electrochromic behavior. 相似文献
Films of titanate nanosheets (approx. 1.8-nm layer thickness and 200-nm size) having a lamellar structure can form electrolyte-filled semi-permeable channels containing tetrabutylammonium cations. By evaporation of a colloidal solution, persistent deposits are readily formed with approx. 10-μm thickness on a 6-μm-thick poly(ethylene-terephthalate) (PET) substrate with a 20-μm diameter microhole. When immersed in aqueous solution, the titanate nanosheets exhibit a p.z.c. of − 37 mV, consistent with the formation of a cation conducting (semi-permeable) deposit. With a sufficiently low ionic strength in the aqueous electrolyte, ionic current rectification is observed (cationic diode behaviour). Currents can be dissected into (i) electrolyte cation transport, (ii) electrolyte anion transport and (iii) water heterolysis causing additional proton transport. For all types of electrolyte cations, a water heterolysis mechanism is observed. For Ca2+ and Mg2+ions, water heterolysis causes ion current blocking, presumably due to localised hydroxide-induced precipitation processes. Aqueous NBu4+ is shown to ‘invert’ the diode effect (from cationic to anionic diode). Potential for applications in desalination and/or ion sensing are discussed.
The conditions for cloud point extraction of lead(II) from aqueous solutions were investigated and optimized. The procedure
is based on the separation of Pb(II) – brillant cresyl blue (BCB) complexes into the micellar media by adding the surfactant
Triton X-114. After phase separation, the surfactant-rich phase was dissolved with 1 mol L−1 HNO3 in ethanol and diluted with 1 mol L−1 HNO3 solution before lead was determined by flame atomic absorption spectrometry. Optimization of the pH, ligand and surfactant
quantities, incubation time, temperature, viscosity, sample volume, and interfering ions was performed. The effects of the
matrix ions were also examined. The detection limits for three times the standard deviations of the blank for lead were 7.5 μg L−1 for water samples and 0.33 μg g−1 for sediment samples. The validity of cloud point extraction was checked by employing certified reference samples of Lake
Sediment IAEA-SL-1 and Sewage Sludge BCR-CRM 144R. The procedure was applied to natural waters and sediment samples with satisfactory
results (recoveries >95%, relative standard deviations <6.4%). 相似文献