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31.
在水热环境下,将Na10[α-SiW9O34]爛18H2O和CuCl2爛2H2O在2,2′-联咪唑和4,4′-联吡啶存在下反应合成一种饱和Keggin硅钨酸盐杂化物[Cu(biim)2]4[α-SiW12O40]2爛4H2O(1),并通过红外光谱,X射线光电子能谱和X射线单晶衍射进行了结构表征.化合物1分子包含2个中性的Keggin[Cu(biim)2]2[α-SiW12O40]单元和4个结晶水分子.值得注意的是在[α-SiW12O40]4-单元中,与硅原子相连的每个氧原子无序排列在两个位置,这导致了硅原子呈现立方体的几何构型.中性Keggin型[Cu(biim)2]2[α-SiW12O40]单元具有中心对称性,两个[Cu(biim)2]2+配离子对称连接在[α-SiW12O40]4-的两端.邻近的[Cu(biim)2]2[α-SiW12O40]单元之间通过氢键作用形成三维的超分子结构. 相似文献
32.
S. Raj Mohan M. P. Joshi C. Shalu C. Ghosh C. Mukharjee L. M. Kukreja 《Journal of Polymer Science.Polymer Physics》2015,53(20):1431-1439
Charge transport properties in thin films of Poly(2‐methoxy‐5‐(3′,7′‐dimethyloctyloxy)‐1,4‐phenylenevinylene) (MDMO PPV) cast using either chloroform (CF), toluene (TOL), or chlorobenzene (CB) as solvent were investigated. Hole mobility (μ) in these thin films measured using time‐of‐flight transient photoconductivity showed an increasing trend with respect to the solvent used in the same order, that is, μCF (2.4 × 10?7 cm2/Vs) < μTOL (6.9 × 10?7 cm2/Vs) < μCB (2.3 × 10?6 cm2/Vs). Observed variations in mobilities were attributed to different morphologies of MDMO PPV chains in thin films cast using the aforesaid solvents. Nature of the interchain interactions and aggregate formation were obtained using photoluminescence (PL), Raman spectroscopy, and AFM studies. Ratio of PL peak intensities of 0–0 and 0–1 transitions, which is a direct measure of interchain interaction, was the highest in CB and lowest in CF. Variation in the relative intensities of out‐of‐plane wagging of vinylene group (~963 cm?1 mode) in Raman spectra suggested different extent of coiling of polymer chains in these thin films. From these observations, it was elicited that aggregate size and interchain interactions are highest in CB and least in CF. AFM‐based topographic images of thin films further supported these variations in the size of aggregates. Variation in the aggregate sizes and interchain interactions explained the corresponding variation in the mobility. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1431–1439 相似文献
33.
A novel Ni/Na – containing inorganic-organic hybrid supramolecule {(PW12O40)·[Na2(NiH2EDTA·H2O)(H4EDTA)·2H2O]·2H2O·H3O}n (short for NiEDTA-PW12) has been successfully synthesized by solution method, and investigated by thermogravimetric-differential thermal analysis (TG-DTA), ultraviolet visible (UV-Vis) spectroscopy, cyclic voltammetry (CV), photoluminescence (PL), ultraviolet visible diffuse reflectance spectrum (UV-vis DRS) and single-crystal X-ray diffraction (XRD). NiEDTA-PW12 exhibits intriguing infinite supramolecular structure with Na+ ions as linker. Furthermore, NiEDTA-PW12 displays a fast-responsive reversible photochromism under ultraviolet or visible light. The photochromic property of NiEDTA-PW12 has been investigated by techniques of UV-vis DRS and PL, and the impact of the O2 on fading of the colored NiEDTA-PW12 has been investigated. 相似文献
34.
The steady flow and heat transfer of a hybrid nanofluid past a permeable stretching/shrinking wedge with magnetic field and radiation effects are studied. The governing equations of the hybrid nanofluid are converted to the similarity equations by techniques of the similarity transformation. The bvp4c function that is available in MATLAB software is utilized for solving the similarity equations numerically. The numerical results are obtained for selected different values of parameters. The results discover that two solutions exist, up to a certain value of the stretching/shrinking and suction strengths. The critical value in which the solution is in existence decreases as nanoparticle volume fractions for copper and wedge angle parameter increase. It is also found that the hybrid nanofluid enhances the heat transfer rate compared with the regular nanofluid. The reduction of the heat transfer rate is observed with the increase in radiation parameter. The temporal stability analysis is performed to analyze the stability of the dual solutions, and it is revealed that only one of them is stable and physically reliable. 相似文献
35.
In this article, we have developed an overlapping Schwarz method for a weakly coupled system of convection-diffusion equations. The method splits the original domain into two overlapping subdomains. A hybrid difference scheme is proposed in which on the boundary layer region, we use the central finite difference scheme on a uniform mesh, whereas on the nonlayer region, we use the mid-point difference scheme on a uniform mesh. It is shown that the numerical approximations converge in the maximum norm to the exact solution. We have proved that, when appropriate subdomains are used, the method produces almost second-order convergence. Furthermore, it is shown that two iterations are sufficient to achieve the expected accuracy. Numerical examples are presented to support the theoretical results. The main advantage of this method used with the proposed scheme is that it reduces iteration counts very much and easily identifies in which iteration the Schwarz iterate terminates. 相似文献
36.
37.
《Mendeleev Communications》2022,32(2):234-237
Starting from the functional cyclotriphosphazene, polysiloxane and nano-SiO2 precursors, three new hybrid nanocomposites with reinforced mechanical properties were prepared. Young’s modulus values for all the composite samples are similar in the range of 7–11 MPa, stress at fracture increases with the nano-SiO2 content increase in the material and reaches a maximum value of 36 MPa for the composite with 20% nano-SiO2. The nanocomposites investigated are elastic and demonstrate the ability to be deformed without failure up to 54% strain. 相似文献
38.
《Physics letters. A》2020,384(20):126513
An interaction mechanism between graphene and magnetic film in cavity is presented in this work. The pseudospin in graphene can indirectly interact with the spins in magnetic film by the media of a circularly polarized photons under the conditions of high temperature and intense laser field. The interaction energy as well as the average values of pseudospin and spin components are calculated according to a generating functional approach. This interaction mechanism provides a scheme of detecting the pseudospin polarization effect. 相似文献
39.
Yoongook Park 《Molecular Crystals and Liquid Crystals》2020,705(1):135-140
AbstractOptically clear adhesives (OCAs) are widely used in optoelectronic displays because of their high outdoor visibility. Here, we develop new transparent adhesive films with wide-viewing-angle characteristics using poly(methyl methacrylate) (PMMA)/TiO2 core–shell micro/nanoparticles. TiO2 nanoparticles are embedded in the shell of PMMA microparticles, forming an organic–inorganic hybrid structure. To examine the optical transmittance of the films in the visible wavelength region, ultraviolet-visible spectroscopy is performed and light diffusion is evaluated. The TiO2 nanoparticles in the shell of the PMMA microparticles exhibit improved light scattering, and the new functional OCAs are expected to provide wide-viewing-angle characteristics for future flexible displays. 相似文献
40.
Dr. A. F. Eftaiha Dr. Abdussalam K. Qaroush Ghada G. Kayed Abdel Rahman K. Abdel Rahman Dr. Khaleel I. Assaf Prof. Dr. Matthew F. Paige 《Chemphyschem》2020,21(16):1858-1865
A series of water soluble, surface-active ionic liquids (SAILs), namely, 1-alkyl-3-methyl imidazolium chlorides ([Cn-mim]Cl) and their mixtures with palmitic acid (PA) are investigated in Langmuir monolayers and Langmuir–Blodgett films. It is inferred from the surface pressure-area isotherms that C16-mim-IL mixes non-ideally with PA and stabilizes the binary mixed films. In addition, the residence of mim-IL at the water surface is enhanced as a function of the increasing alkyl side chain length. Generally, the compressional moduli values decrease upon increasing the content of the mim-ILs over a wide range of compositions. Furthermore, film relaxation measurements indicate that the IL component is selectively excluded from the mixed films upon achieving a certain target pressure. Brewster angle microscope images demonstrate minimal changes on the PA domains in the presence of either C4- and C8-mim-ILs, whereas presence of the hexadecyl counterpart results in the formation of condensed sheets. Atomic force microscopy imaging of deposited films show the formation of propeller-like aggregates when C8- or C16-mim-IL is present in the mixed films. 相似文献