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排序方式: 共有209条查询结果,搜索用时 31 毫秒
91.
Manochehr Bahmaeia Roya Pourzarea Amir Ghezloo 《Russian Journal of General Chemistry》2013,83(12):2386-2391
The steel samples have been coated with cerium layer by cathodic electrolytic deposition from the Ce(NO3)3·6H2O solution in aqueous ethyleneglycol in the presence of hydrogen peroxide. The influence of the coating parameters (cathodic current density, pH, cerium concentration, hydrogen peroxide concentration, temperature, and treatment duration) on the surface properties; the optimum conditions of the formation of corrosion preventing coating have been elucidated. Hydrogen peroxide concentration and pH are the major factors influencing the deposition process. The corrosion resistance has been further enhanced after treatment with Na3PO4·12H2O solution. The cerium-coated samples have been subsequently coated by cathodic electrostatic deposition from the colloidal solution of the paint. The coated materials have been subjected to mechanical testing (hardness, impact, cross cut, bending, and cupping tests), and their structure has been visualized by electron microscopy. The cerium coating has been found to improve the steel corrosion resistance by 15%. 相似文献
92.
Simply synthesized TiO_2 nanorods as an effective scattering layer for quantum dot sensitized solar cells
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TiO2 nanorod layers are synthesized by simple chemical oxidation of Ti substrates. Diffuse reflectance spectroscopy measurements show effective light scattering properties originating from nanorods with length scales on the order of one micron. The films are sensitized with CdSe quantum dots (QDs) by successive ionic layer adsorption and reaction (SILAR) and integrated as a photoanode in quantum dot sensitized solar cells (QDSCs). Incorporating nanorods in photoanode structures provided 4- to 8-fold enhancement in light scattering, which leads to a high power conversion efficiency, 3.03% (Voc = 497 mV, Jsc = 11.32 mA/cm2, FF = 0.54), in optimized structures. High efficiency can he obtained just by tuning the photoanode structure without further treatments, which will make this system a promising nanostructure for efficient quantum dot sensitized solar cells. 相似文献
93.
Roya Beheshti 《Mathematische Annalen》2014,360(3-4):753-768
We study smooth hypersurfaces of degree \(d\ge n+1\) in \(\mathbf{P}^n\) whose spaces of smooth rational curves of low degrees are larger than expected, and show that under certain conditions, the primitive part of the middle cohomology of such hypersurfaces have non-trivial Hodge substructures. As an application, we prove that the space of lines on any smooth Fano hypersurface of degree \(d \le 8\) in \(\mathbf{P}^n\) has the expected dimension \(2n-d-3\) . 相似文献
94.
System reliability, especially for serial parallel systems, has attracted much attention in recent years. Redundancy allocation is a technique to increase the reliability of the serial parallel systems. Supplying redundant components depends on some restrictions such as available budget, weight, space, etc. This paper proposes a new model for redundancy allocation problems (RAPs) by considering discount policy. The proposed model attempts to maximize the reliability of a system by gathering various components where there are some limitations on budgeting. We present two models with different assumptions including all unit discount and incremental discount strategies. The resulted formulations are nonlinear integer models and categorized as NP-hard. Therefore, some heuristics and meta-heuristics are designed to solve the resulted models, efficiently. 相似文献
95.
The first application of in situ-generated N-thiocyanatosuccinimide (NTS) for the thiocyanation of alcohols is described. This method can be easily applied for the facile conversion of primary, secondary and tertiary alcohols into the corresponding alkyl thiocyanates or alkyl isothiocyanates in good to excellent yields. 相似文献
96.
Nasser Iranpoor Habib Firouzabadi Roya Azadi 《Journal of organometallic chemistry》2010,695(6):887-6235
The use of an imidazolium-based phosphinite ionic liquid (IL-OPPh2) as both solvent and ligand for Pd offers an efficient catalytic system for silylation of aryl iodides, bromides and also chlorides by triethylsilane in the presence of Cs2CO3. In the absence of base, this system is also performed for catalytic dehalogenation of aryl halides. The ionic liquid containing its corresponding Pd(0) complex can be easily recovered and reused in several runs without losing its efficiency. 相似文献
97.
Roya Majidi 《Physica B: Condensed Matter》2012,407(19):4005-4007
In the present work, we have compared the resistance of the 90°, 180°, and 360° domain walls in the presence of external magnetic field. The calculations are based on the Boltzmann transport equation within the relaxation time approximation. One-dimensional Néel-type domain walls between two domains whose magnetization differs by angle of 90°, 180°, and 360° are considered. The results indicate that the resistance of the 360° DW is more considerable than that of the 90° and 180° DWs. It is also found that the domain wall resistance can be controlled by applying transverse magnetic field. Increasing the strength of the external magnetic field enhances the domain wall resistance. In providing spintronic devices based on magnetic nanomaterials, considering and controlling the effect of domain wall on resistivity are essential. 相似文献
98.
In this work we continue the study of a family of 1D piecewise smooth maps, defined by a linear function and a power function with negative exponent, proposed in engineering studies. The range in which a point on the right side is necessarily mapped to the left side, and chaotic sets can only be unbounded, has been already considered. In this work we are characterizing the remaining ranges, in which more iterations of the right branch are allowed and in which divergent trajectories occur. We prove that in some regions a bounded chaotic repellor always exists, which may be the only non-divergent set, or it may coexist with an attracting cycle. In another range, in which divergence cannot occur, we prove that unbounded chaotic sets always exist. The role of particular codimension-two points is evidenced, associated with fold bifurcations and border collision bifurcations (BCBs), related to cycles having the same symbolic sequences. We prove that they exist related to the border collision of any admissible cycle. We show that each BCB, each fold bifurcation and each homoclinic bifurcation is a limit set of infinite families of other BCBs. 相似文献
99.
Roya Akbarzadeh Ghazaleh Imani Shakibaei Ayoob Bazgir 《Monatshefte für Chemie / Chemical Monthly》2010,15(1):1077-1081
Abstract
An efficient and simple synthesis of ferrocenyl 3-aminoimidazo[1,2-a]pyridines by the three-component reaction of ferrocenecarboxaldehyde, isocyanides, and 2-aminopyridines in the presence of a catalytic amount of InCl3 in ethanol at room temperature is reported. 相似文献100.