Papers by Keyword: Hollow Sphere

Abstract: A kind of ordered meso-sized hollow silica spherical material was prepared by hydrothermal route using monodispersed cross-linked polymethyl polymer spheres as template, metacrylate tetraethyl orthosilicate as a silica source. The calcination was empolyed for the removing of template and generation silica hollow spherical materials with meso-sized pores. The adsorption performance of the obtained hollow silica spheres was investigated and the results indicated that the obtained hollow silica spheres had high adsorption capacity for sulfadimethoxine. They were sucessfully used as the dispersive adsorbent for matrix solid phase dispersive extraction sulfadimethoxine from chicken tissue with satisfactory results.

Abstract: Hollow sodalite spheres were prepared in water-soluble polymer polyacrylamide hydrogels (PAM) which were used as "soft template". The samples were characterized by XRD and SEM. The influence of the contents of initiator (ammonium persulfate) and crosslinker (N,N’-methylene-bis-acrylamide) on the size and morphology of hollow sodalite spheres was investigated. The results showed that the pore sizes of hollow sodalite spheres significantly decreased and the shell thicknesses thickened as the amount of initiator increased. The amount of MBAM affected the crystallization of sodalite, stacked arrangement and hollow structure. When the amounts range of MBAM was 0.8%-1.6%, hollow sodalite spheres were non-friable and smaller than the others, and their arrangement was uniform and orderly.

Abstract: This paper presents the effect of centrifugal load in functionally graded hollow sphere. Analytical solution for stresses is determined using the direct method and the power series method. The material stiffness varies continuously across the thickness direction according to the power law functions of radial directions. Increasing the angular velocity results in increasing the all above quantities. With increasing the power law indices the radial displacement, the shear and circumferential stresses due to centrifugal load all are decreased and the radial stress due to centrifugal load increased.

Abstract: NH4Al (OH) 2CO3 (AACH) hollow spheres and solid spheres were successfully synthesized with water in oil in water (W/O/W) emulsion, applying the liquid-to-liquid-phase boundary of the micellar system as a template. During the facile procedure, no high pressure, high temperature, or other complex reaction conditions were required. Transmission electric microscope (TEM) images showed that all the hollow structural products have a good spherical morphology with an average diameter of 1 μm. The as-synthesized spheres had large diameters and thin shells of about 30 nm composed of numerous small nanocrystals. In addition, the AACH product can be calcined into Al2O3 without changing its shape.

Abstract: TiO₂ hollow microspheres were synthesized by a facile solvothermal method. The prepared samples were characterized by the XRD, SEM, TEM, BET and UV-vis. The results showed that the TiO₂ hollow microspheres offered an enhanced photocatalytic activity due to the multiple reflections of the UV light within the inner hollow structure.

Abstract: Using aluminum sulfate as precursor and urea as precipitator, hollow sphere boehmite was synthesized by hydrothermal treatment on 140°C for 24h. The time effect of as-synthesized product was studied by XRD, SEM and TG, et al. The results show that with the hydrothermal time increasing the product’s phase transformed from sodium sulfate aluminum to amorphous form to mixture phases of sodium sulfate aluminum and boehmite to boehmite. After 24h hydrothermal treatment, the product can completely change to boehmite. With the hydrothermal time increasing, the micromorphology of hydrolysis product experienced the evolution of smooth dense globe to core-shell sphere to hollow sphere.

Abstract: This work studied the theoretical solution for axisymmetric steady-state mechanical and thermal stresses in hollow functionally graded spheres with respect to heat source. The material properties of the FG sphere change continuously across the thickness direction according to the power functions of radial direction. The steady-state temperature, displacements, and stresses are derived due to the general mechanical and thermal boundary conditions as function of radial and circumferential directions. The temperature and Navier equations are solved analytically, using Taylor and Legendre series. With increasing the power law indices the temperature distribution due to heat source is decreased. Circumferential stress and radial displacement due to heat source are decreased as the power law index increases.

Abstract: Taking pipe - hollow spherical node as the object, and using ANSYS finite element analysis software, established five kinds of finite element model to analyze the stress concentration at the weld connection of the different connections of steel structures - hollow ball under the uniaxial tension. Obtained this node’s stress concentration factor, stress distribution, by changing the hollow spherical diameter and wall thickness, pipe’s diameter and wall thickness, obtained the trend of the stress concentration factor under different control ball matches. Take static tests on typical structures of two specifications 6 hollow sphere nodes, get the measured stress concentration factor, and stress distribution of this node. Through comparative analysis of theoretical analysis and experimental results, show that the two rules are consistent. The research results can provide basis for improving the pipe - hollow spherical joints connecting structural.

Abstract: Three different CeO2 sphere nanomaterials (hollow sphere, flowerlike sphere, spherical cluster) were controllably synthesized by carbon sphere template method, hydrothermal and solvothermal method respectively. Then 2.5 wt% Au was doped on the supports by the deposition precipitation method and Au/CeO2 catalysts with three different morphologies were obtained. Composition, morphology and structure of these catalysts were characterized by the techniques of XRD, Raman, TPR, SEM and TEM, and the activity for CO oxidation of the catalysts was investigated. The catalytic test results indicated that the addition of Au could remarkably improve catalytic performance on CO oxidation. The activities of the three catalysts differ largely, the flowerlike Au/CeO2 catalyst had the highest activity for CO oxidation and its T100% was 29°C. The mechanism for the different activity of the catalysts was investigated. H2-TPR result indicated flowerlike had a more intensive peak at 125°C than others and it implied more reducible Au species in this case, that plays a vital role in the CO oxidation.

Abstract: Ni-Se powders synthesized by hydrothermal co-reduction method from NiCl2.6H2O and SeO2 at 95～220 °C. The phases and morphology of the products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) respectively. Experimental results show that, Ni0.85Se can be synthesized at 95～220 °C while noticeable impurities appeared at lower reaction temperatures. The products with single-phase Ni0.85Se obtained at 200 and 220 °C show hollow sphere structures with diameters of about 150 ~ 700 nm, which have complete and regular shape but no holes.