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51.
Dr. Hao‐Yiang Wu Prof. Fa‐Kuen Shieh Prof. Hsien‐Ming Kao Yi‐Wen Chen Dr. Juti Rani Deka Shih‐Hsiang Liao Prof. Kevin C.‐W. Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(20):6358-6367
Highly ordered benzene‐bridged periodic mesoporous organosilicas (PMOs) that were functionalized with exceptionally high loadings of carboxylic acid groups (COOH), up to 80 mol % based on silica, have been synthesized and their use as adsorbents for the adsorption of methylene blue (MB), a basic dye pollutant, and for the loading and release of doxorubicin (DOX), an anticancer drug, is demonstrated. These COOH‐functionalized benzene? silicas were synthesized by the co‐condensation of 1,4‐bis(triethoxysilyl) benzene (BTEB) and carboxyethylsilanetriol sodium salt (CES), an organosilane that contained a carboxylic acid group, in the presence of non‐ionic oligomeric surfactant Brij 76 in acidic medium. The materials thus obtained were characterized by a variety of techniques, including powder X‐ray diffraction (XRD), nitrogen‐adsorption/desorption isotherms, TEM, and 13C and 29Si solid‐state NMR spectroscopy. Owing to the exceptionally high loadings of COOH groups, their high surface areas, and possible π? π‐stacking interactions, these adsorbents have very high adsorption capacities and extremely rapid adsorption rates for MB removal and for the controlled loading/release of DOX, thus manifesting their great potential for environmental and biomedical applications. 相似文献
52.
Complex coacervation of gelatin A and sodium alginate was carried out to obtain the maximum coacervate yield. Turbidity and coacervate yield (%) measurements were carried out to support the ratio of the two polymers and pH that produced maximum coacervation. The optimum ratio between gelatin A-sodium alginate and pH to form the maximum coacervate complex was found to be 3.5:1 and 3.5–3.8, respectively. Olive oil microencapsulation was carried out at the optimized ratio and pH. Microcapsules were crosslinked by using glutaraldehyde. Scanning electron microscopy studies confirmed the formation of free flowing spherical microcapsules of different sizes. The size of microcapsules increased with the increase in the concentration of the polymer. The encapsulation efficiency and the release rates of olive oil were dependent on the amount of crosslinker, oil loading and polymer concentration. Thermogravimetric study revealed improvement of thermal stability with crosslinking. Fourier Transform Infrared Spectroscopy study showed that there was no significant interaction between olive oil and gelatin-alginate complex. 相似文献
53.
In the present work effect of 90 MeV O7+ ions with five different fluences on poly(ethylene oxide) (PEO)/Na+-montmorillonite (MMT) nanocomposites has been investigated. PEO/MMT nanocomposites were synthesized by solution intercalation technique. With the increase in irradiation fluence, gallery spacing of MMT increases in the composite and an exfoliated nanostructure is obtained at the fluence of 5?×?1012 ions/cm2 as revealed by X-ray diffraction results. Highest room temperature ionic conductivity of 4.2?×?10?6?S?cm?1 was found for the fluence 5?×?1012 ions/cm2, while the conductivity for unirradiated polymer electrolyte was found to be 7.5?×?10-8?S?cm?1. The increase in intercalation of PEO chains inside the galleries of MMT results in the increase in interaction between Na+ cation and oxygen heteroatom leading to the increase in ionic conductivity of the composites. Surface morphology and interactions among the various constituents in the nanocomposites at different fluence have been examined by scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The appearance of peak for each fluence in the loss tangent suggests the presence of relaxing dipoles in the polymer nanocomposite electrolyte films. With the increase in ion fluence the peak shifts towards higher frequency side, suggesting decrease in the relaxation time. 相似文献
54.
Mesoporous TiO2 microspheres with high specific surface areas were synthesized by means of a facile one‐step microwave hydrothermal process without using any template. The mesoporous materials were rapidly achieved using TiCl4, urea and ammonium sulphate at comparatively low microwave power (400 W) for 8 min irradiation. The morphology and microstructure of the as‐prepared products were characterized by field emission scanning electron microscopy (FESEM), X‐ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer‐Emmett‐Teller (BET) surface area analysis. Structural characterization indicates that the TiO2 microspheres display mesoporous structure. The average pore sizes and BET surface areas of the spheres were 5.3 nm and 222 m2g?1, respectively. The mesoporous nanocrystals synthesized at 160 °C for 8 min were then used to prepare the photoanode for dye sensitized solar cells (DSSCs). A high power conversion efficiency of 5.72% was achieved from the mesoporous TiO2 based photoanode, representing about 25.7% improvement over the efficiency of P25 photoanode. 相似文献
55.
56.
Sasanka Deka 《Solid State Communications》2005,134(10):665-669
The electronic structure of polycrystalline ferromagnetic Zn1−xCoxO (0.05≤x≤0.15) and the oxidation state of Co in it, have been investigated. The Co-doped polycrystalline samples are synthesized by a combustion method and are ferromagnetic at room temperature. XPS and optical absorption studies show evidence for Co2+ ions in the tetrahedral symmetry, indicating substitution of Co2+ in the ZnO lattice. However, powder XRD and electron diffraction data show the presence of Co metal in the samples. This give evidence to the fact that some Co2+ ion are incorporated in the ZnO lattice which gives changes in the electronic structure whereas ferromagnetism comes from the Co metal impurities present in the samples. 相似文献
57.
A theoretical study is made on the amplification mechanism of electrostatic Bernstein mode wave in presence of kinetic Alfven wave turbulence in a magnetized plasma on the basis of plasma-maser interaction. It is shown that a test high frequency electrostativ Bernstein mode wave is unstable in the presence of low frequency kinetic Alfven wave turbulence. The growth rate of the Bernstein wave vanishes only in an unmagnetized plasma. Because of the universal existence of the kinetic Alfven waves in large scale plasmas, the results have potential importance in space and astrophysical radiation processes. 相似文献
58.
Interaction of Bernstein mode wave with ion-acoustic turbulence is treated as the plasma maser effect. Ion-acoustic turbulence
is considered as resonant mode, propagating orthogonal to the test Bernstein mode. The external magnetic field, in the direction
of ion-acoustic turbulence, is playing key role in transferring energy in upconversion process from resonant low frequency
wave to the high frequency wave through modulated electric field. It is shown that the direct coupling term and the associated
reverse absorbtion effect do not contribute individually to the growth or damping to the Bernstein mode. Only the polarization
coupling term is found to be effective in the energy upconversion process as the external magnetic field is providing momentum
in the direction of propagation of Bernstein mode. The polarization coupling term is identified to be the dominant upconversion
factor in the plasma maser effect. 相似文献
59.
E. A. Ivanova-Shor A. M. Shor S. S. Laletina R. Ch. Deka V. A. Nasluzov 《Russian Chemical Bulletin》2017,66(5):759-768
The review is dedicated to the elaboration and application of hybrid quantum mechani-cal/molecular mechanical methods for heterogeneous catalytic systems, including single atoms and clusters of transition metals immobilized on covalent oxide supports. The following issues are considered: (1) elaboration of the hybrid covEPE method for modeling of covalent sys-tems of the zeolite and silicate types, (2) computations of the properties of atoms and small titanium, rhodium, iridium, and gold clusters localized in cavities or embedded in the zeolite framework, and (3) computations of small silver and tantalum clusters anchored at the dehydr-oxylated and hydroxylated silica surfaces. The calculations were performed by the density functional theory (DFT) with the Becke—Perdew (BP) exchange-correlation potential. 相似文献
60.
We present some congruences involving the functions c?4(n) and which denote, respectively, the number of generalized Frobenius partitions of n with 4 colors and 4-order generalized Frobenius partitions of n with 4 colors. 相似文献