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121.
Heath Fletcher Christine C. Allen Robert C. Burns Donald C. Craig 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(5):505-507
The title compound, K5[BW12O40]·16H2O, contains a [BW12O40]5? polyanion of 222 crystallographic symmetry, with a central tetrahedrally coordinated BIII atom surrounded by four groups of three edge‐sharing octahedra (W3O13 subunits), which are linked in turn to each other and to the central BO4 tetrahedron by shared O atoms at the vertices. There is a crystallographically unique B—O bond of 1.554 (10) Å, while the average W—O distances are 2.344 (17) Å for four coordinate O atoms, 1.917 (12) and 1.89 (2) Å for two coordinate O atoms within and connecting the W3O13 subunits, respectively, and 1.709 (8) Å for terminal O atoms. Not all of the K+ ions and H2O groups were located. 相似文献
122.
123.
Anam Safri Ashleigh Jane Fletcher Ramsha Safri Hifza Rasheed 《Molecules (Basel, Switzerland)》2022,27(23)
Recent studies on the removal of pollutants via adsorption include the use of carbon-based adsorbents, due to their high porosity and large surface area; however, such materials lack photoactive properties. This study evaluates the synergistic effect of integrated mesoporous carbon xerogel (derived from resorcinol formaldehyde) and titanium dioxide (TiO2) for combined adsorption and photodegradation application. The complex formed between carbon xerogel and TiO2 phase was investigated through FTIR, proving the presence of a Ti-O–C chemical linkage. The physicochemical properties of the synthesised adsorbent–photocatalyst were probed using FESEM, BET analysis and UV–Vis analysis. The kinetics, equilibrium adsorption, effect of pH, and effect of adsorbent dosage were investigated. The expansion of the absorbance range to the visible range was verified, and the corresponding band gap evaluated. These properties enabled a visible light response when the system was exposed to visible light post adsorption. Hence, an assistive adsorption–photodegradation phenomenon was successfully executed. The adsorption performance exhibited 85% dye degradation which improved to 99% following photodegradation. Further experiments showed the reduction of microorganisms under visible light, where no microbial colonies were observed after treatment, indicating the potential application of these composite materials. 相似文献
124.
John Galletly J. Fletcher und A. Percy Smith 《Fresenius' Journal of Analytical Chemistry》1881,20(1):267-268
Ohne Zusammenfassung 相似文献
125.
Yujie Xia Tao Li Chao Yuan Cameron Fletcher Xinyue Dai Xingfan Zhang Lishu Zhang Prof. Dr. Yanyan Jiang Dr. Hui Li 《Chemphyschem》2020,21(6):568-574
The electron transport properties of polycyclic aromatic hydrocarbons (PAHs) with different numbers of benzene rings tethered to narrow zigzag graphene nanoribbon (ZGNR) electrodes have been investigated. Results show that the transport properties of PAHs are dependent on whether the number of benzene rings in the width direction is odd or even. This effect is strong for narrow width PAHs, but its strength decreases as the width of the PAH is increased. PAHs with an odd number of rings exhibit poor transport properties, whereas the ones having an even number of rings show excellent transport properties coupled with a negative differential resistance (NDR) effect. Moreover, the linkage points and the structure of the molecules have a noticeable effect on the transport properties of the PAH, making the odd-even effect weaker or disappear entirely. Although the PAH with three benzene rings displays poor transport capabilities, it shows excellent rectification behavior compared to the other examined molecules. These studies present a feasible avenue for designing molecular devices with enhanced performance by the careful manipulation of the PAH molecular structure. 相似文献
126.
The purpose of this paper is to define a uniformity on a frame using entourages. A definition of uniformities in terms of covers has been given byA. Pultr ([8], [10]). We introduce two new symmetry conditions for a quasi-uniform space, open-set symmetry and small-set symmetry. We prove that a quasi-uniformityU is a uniformity if and only if it is both open-set symmetric and small-set symmetric. The category of (covering) uniform frames is isomorphic with the category of entourage uniform frames. 相似文献
127.
Winifred M. Huo Christopher E. Dateo Graham D. Fletcher 《Radiation measurements》2006,41(9-10):1202-1208
As part of the database for building up a biochemical model of DNA radiation damage, electron impact ionization cross sections of sugar-phosphate backbone and DNA bases have been calculated using the improved binary-encounter dipole (iBED) model. It is found that the total ionization cross sections of - and -deoxyribose-phosphate, two conformers of the sugar-phosphate backbone, are close to each other. Furthermore, the sum of the ionization cross sections of the separate deoxyribose and phosphate fragments is in close agreement with the - and -deoxyribose-phosphate cross sections, differing by less than 10%, an indication that a building-up principle may be applicable. Of the four DNA bases, the ionization cross section of guanine is the largest, then in decreasing order, adenine, thymine, and cytosine. The order is in accordance with the known propensity of oxidation of the bases by ionizing radiation. Dissociative ionization (DI), a process that both ionizes and dissociates a molecule, is investigated for cytosine. The DI cross section for the formation of H and (cytosine-H1)+, with the cytosine ion losing H at the 1 position, is also reported. The threshold of this process is calculated to be 16.9 eV. Detailed analysis of ionization products such as in DI is important to trace the sequential steps in the biochemical process of DNA damage. 相似文献
128.
R. S. Fletcher 《Physics letters. [Part B]》1994,320(3-4):373-376
We study the survival probability for rapidity gaps in a model which includes diffractive dissociation. A Good-Walker model implementation of the minijet model, which consistently includes inelastic diffraction, predicts a much larger survival probability than previous calculations. 相似文献
129.
D.O Harrison R. Thomas A.E. Underhill J.K. Fletcher P.S. Gomm F. Hallway 《Polyhedron》1985,4(4):681-685
The preparation, spectroscopic and magnetic properties are reported for complexes of iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) with th 相似文献
130.