Preparation,characterization of Fe,Ce Co-doped flower-like TiO2 photocatalysts and their properties in photocatalytic oxidation of arsenite

Russian Journal of Physical Chemistry A - Preoxidation process is usually needed in the treatment of arsenic containing water because arsenite (i.e., As(III)) is less easily to be removed by...     

An intuitionistic fuzzy projection-based approach for partner selection

The partner selection is an important decision problem in the formation of a new virtual enterprise. Using the projection technique, this study introduces an approach to partner selection with linguistic values and intuitionistic fuzzy information under a group decision-making environment. To avoid information loss, there is no aggregations of decision information in this model except ideal decisions as auxiliary decision tools. Comparisons of the suggested methodology with other methods are also made. A numerical example and an experimental analysis are proposed to illustrate the application of the proposed model.     

Fabrication and Luminescent Properties of 6H-SiC/3C-SiC/6H-SiC Quantum Well Structure

Quantum well structure film of 6H-SiC/3C-SiC/6H-SiC was fabricated on 6H-SiC (0001) with the substrate temperature of 1350 K by solid source molecular beam epitaxy (SSMBE) through the variation of Si flux rate. The crystal polytypes and luminescent properties of the film were characterized by reflection high energy electron diffraction (RHEED) and photoluminescence (PL), respectively. The results of RHEED indicated that the film was 6H-SiC/3C-SiC/6H-SiC with the quantum well structure. The results of PL excited by He-Gd laser at room temperature showed that there were intense emissions in the range of 480–600 nm, which could not be observed from the substrate. The fitting peaks were consistent with the results calculated from the model of quantum well structure, which showed that such intense emissions were probably from the quantum wells with different widths.     

An Expedient Approach to the Benzopyran Core: Application to Synthesis of the Natural Products(±)-Xyloketals and(±)-Alboatrin

A mild and efficient protocol for the synthesis of the benzopyran ring has been described and a series of chromans compounds is reported, the yield is from 72% to 95%. The diadduct tended to angular product and showed good regioselectivity. This strategy was applied for the benzopyran derived natural products (±)‐xyloketals and (±)‐alboatrin. The crystal of compound 9 exhibited centro‐symmetric space group, containing two isomers in one unit. The relative configurations were 1R,10R,15S and 34S,22R,30S, respectively.     

Evaluation of two methods to minimize the anticlastic curvature of cylindrical bent crystals

A scanning dynamically focusing sagittal X‐ray monochromator accepting 3 mrad × 0.1 mrad from a 6 T wiggler has been designed for XAFS measurements. In the energy range 4.1–12.4 keV, the slope error of the second cylindrical crystal caused by anticlastic bending must be less than 1/5 of the Darwin width of the crystal or the photon flux will decrease drastically. Two methods to minimize the anticlastic bending are proposed. Thin crystals with stiffening ribs and thin crystals with an aspect ratio equal to the `golden value' are evaluated by finite‐element analysis and by long‐trace‐profiler characterization. Both approaches are satisfactory, but the `golden value' approach is preferred in this case for the second crystal of the new monochromator not only because it is easy to manufacture but also because the surface is smoother than the ribbed crystal.     

Large-scale controllable patterning growth of aligned organic nanowires through evaporation-induced self-assembly

Organic one-dimensional nanostructures are attractive building blocks for electronic, optoelectronic, and photonic applications. Achieving aligned organic nanowire arrays that can be patterned on a surface with well-controlled spatial arrangement is highly desirable in the fabrication of high-performance organic devices. We demonstrate a facile one-step method for large-scale controllable patterning growth of ordered single-crystal C(60) nanowires through evaporation-induced self-assembly. The patterning geometry of the nanowire arrays can be tuned by the shape of the covering hats of the confined curve-on-flat geometry. The formation of the pattern arrays is driven by a simple solvent evaporation process, which is controlled by the surface tension of the substrate (glass or Si) and geometry of the evaporation surface. By sandwiching a solvent pool between the substrate and a covering hat, the evaporation surface is confined to along the edge of the solvent pool. The geometry of the formed nanowire pattern is well defined by a surface-tension model of the evaporation channel. This simple method is further established as a general approach that is applicable to two other organic nanostructure systems. The I-V characteristics of such a parallel, organic, nanowire-array device was measured. The results demonstrate that the proposed method for direct growth of nanomaterials on a substrate is a feasible approach to device fabrication, especially to the fabrication of the parallel arrays of devices.     

Synthesis and Characterization of [Ar′GaC(Ph)CH]2 and K2[Ar′GaC(Ph)CH]2⋅OEt2: From Digallene to Digallacyclohexadiene to Digallatabenzene

On a plane : Addition of PhCCH to Ar′GaGaAr′ (Ar′=2,6‐(2,6‐iPr₂C₆H₃)₂C₆H₃) yielded the 1,4‐digallacyclohexadiene [{Ar′GaC(Ph)CH}₂] ( 1 ), which afforded the 1,4‐digallatabenzene dianion [Ar′GaC(Ph)CH]₂^2? ( 2 ) upon reduction with potassium (see scheme; C gray, Ga green, K blue). Structural parameters, DFT calculations, and ¹H NMR spectroscopy support aromatic character of 2 .

     

Effect of substrate temperature on few-layer graphene grown on Al2O3 (0 0 0 1) via direct carbon atoms deposition

Few-layer graphene (FLG) was grown on Al₂O₃ (0 0 0 1) substrates at different temperatures via direct carbon atoms deposition by using solid source molecular beam epitaxy (SSMBE) method. The structural properties were characterized by reflection high energy electron diffraction (RHEED), Raman spectroscopy and near-edge X-ray absorption fine-structure (NEXAFS). The results showed that the FLG started to form at the substrate temperature of 700 °C. When the substrate temperature increased to 1300 °C, the quality of the FLG was the best and the layer number was estimated to be less than 5. At higher substrate temperature (1400 °C or above), the crystalline quality of the FLG would be deteriorated. Our experiment results demonstrated that the substrate temperature played an important role on the FLG layer formation on Al₂O₃ (0 0 0 1) substrates and the related growth mechanism was briefly discussed.     

Approach to group decision making based on determining the weights of experts by using projection method

The aim of this paper is to present a new approach for determining weights of experts in the group decision making problems. Group decision making has become a very active research field over the last decade. Especially, the investigation to determine weights of experts for group decision making has attracted great interests from researchers recently and some approaches have been developed. In this paper, the weights of experts are determined in the group decision environment via projection method. First of all, the average decision of all individual decisions is defined as the ideal decision. After that, the weight of expert is determined by the projection of individual decision on the ideal decision. By using the weights of experts, all individual decisions are aggregate into a collective decision. Then an ideal solution of alternatives of the collective decision, expressed by a vector, is determined. Further, the preference order of alternatives are ranked in accordance with the projections of alternatives on the ideal solution. Comparisons with an extended TOPSIS method are also made. Finally, an example is provided to illustrate the developed approach.     

Transfer color to night vision images

Natural color appearance is the key problem of color night vision field. In this paper, the color mood of daytime color image is transferred to the monochromic night vision image. This method gives the night image a natural color appearance. For each pixel in the night vision image, the best matching pixel in the color image is found based on texture similarity measure. Entropy, energy, contrast, homogeneity, and correlation features based on co-occurrence matrix are combined as texture similarity measure to find the corresponding pixels between the two images. We use a genetic algorithm (GA) to find the optimistic weighting factors assigned to the five different features. GA is also employed in searching the matching pixels to make the color transfer algorithm faster. When the best matching pixel in the color image is found, the chromaticity values are transferred to the corresponding pixel of the night vision image. The experiment results demonstrate the efficiency of this natural color transfer technique.