112926-00-8Relevant articles and documents
The hydration behavior of Ca-P-Si system via mechanochemical treatment
Yu, Tao,Ye, Jiandong,Zhang, Shujiang
, p. 2990 - 2993 (2010)
In the present study, the Si-substituted amorphous calcium phosphate (Si-ACP) was prepared via a dry-mechanochemical method, and the hydration behavior of Si-ACP was investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electronic microscopy, and the determination of the setting time and compressive strength. The results showed that the mechanochemical treatment had a great effect on the resolution property of Si-ACP, which induced the different hydration behavior. With the presence of Si, the hydration product of Si-ACP showed better results of cell proliferation and metabolic activity, which were characterized by the methyl thiazolyl tetrazolium assay (MTT) with mesenchymal stem cells. This work was expected to have a guiding effect on the study of calcium phosphate cement.
KINETIC STUDY ON HYDROLYSIS OF SILICON PHOSPHATE IN AQUEOUS ALKALINE SOLUTIONS.
Saeki,Narita,Naito
, p. 1591 - 1595 (1984)
Kinetic study of the hydrolysis of silicon phosphate, Si//3(PO//4)//4 (hexagonal), was carried out in borax buffer solutions (pH 5-12, temperature 20-50 degree C) to investigate how it acts as a hardener for alkali silicate adhesive. The silicon phosphate was found to be hydrolyzed with a resulting release of orthophosphate ion, soluble silicate ions, and colloidal silica under mild conditions; the decomposition rate increased with decreasing the particle size of the phosphate and with increasing the pH and temperature of the buffer solution.
AFM studies on the difference in wear behavior between Si and SiO2 in KOH solution
Katsuki, Futoshi,Kamei, Kazuhito,Saguchi, Akihiko,Takahashi, Wataru,Watanabe, Junji
, p. 2328 - 2331 (2000)
Wear behavior between a Si tip and a SiO2 film in KOH solution at various pH values has been examined by using an atomic force microscope. We found that the Si tip removal amount strongly depended on the solution pH value and was at a maximum at pH 10.2-12.5. This result indicates that wear behavior of the Si tip is similar to that of actual chemical mechanical polishing of a Si wafer. It was also found that the Si removal volume in moles was approximately equal to that of SiO2 irrespective of the solution pH value. This equality implies that a Si-O-Si bridge is formed between one Si atom and one SiO2 molecule at the wear interface, followed by the oxidation of the Si tip, and finally the bond rupture by the tip movement and the silica species including the Si-O-Si bridge is dissolved in the KOH solution.
Functionalized mesoporous materials for adsorption and release of different drug molecules: A comparative study
Wang, Gang,Otuonye, Amy N.,Blair, Elizabeth A.,Denton, Kelley,Tao, Zhimin,Asefa, Tewodros
, p. 1649 - 1660 (2009)
The adsorption capacity and release properties of mesoporous materials for drug molecules can be improved by functionalizing their surfaces with judiciously chosen organic groups. Functionalized ordered mesoporous materials containing various types of org
Study of Ge bonding and distribution in plasma oxides of Si1-xGex alloys
Seck,Devine,Hernandez,Campidelli,Dupuy
, p. 2748 - 2750 (1998)
Secondary ion mass spectroscopy (SIMS) and Fourier transform infrared (FTIR) absorption have been studied in thin oxides of Si1-xGex grown by plasma oxidation. SIMS analysis reveals that Ge can migrate to the oxide film surface leavi
Effect of Mie resonance on photocatalytic hydrogen evolution over dye-sensitized hollow C-TiO2 nanoshells under visible light irradiation
Yao, Xiaxi,Hu, Xiuli,Cui, Yingying,Huang, Jialei,Zhang, Wenjun,Wang, Xuhong,Wang, Dawei
, p. 750 - 754 (2021)
Light utilization is one of the key factors for the improvement of photocatalytic performance. Herein, we design C-TiO2 hollow nanoshells with strong Mie resonance for enhanced photocatalytic hydrogen evolution in a dye-sensitized system under visible light irradiation (λ ≥ 420 nm). By tuning the inner diameters of hollow nanoshells, the Mie resonance in hollow nanoshells is adjusted for better excitation of dye molecules, which thus greatly enhances the light utilization in visible light region. This work shows the potential of Mie resonance in nanoshells can be an alternative strategy to increase the light utilization for photocatalysis.
Synthesis of magnesium silicate by heat treatment of sols and mechanical activation of solid components
Dudkin,Vasyutin
, p. 751 - 755 (2011)
A layered magnesium silicate, an analog to natural talc, was synthesized by mechanical treatment of a mixture of magnesium hydroxide and hydrated silicic acid powders, as well as by heat treatment of aqueous dispersions containing magnesium hydroxide particles and silica sols prepared from different precursors.
Synthesis of surfactant-templated silica films with orthogonally aligned hexagonal mesophase
Koganti, Venkat R.,Rankin, Stephen E.
, p. 3279 - 3283 (2005)
Thin silica films with orthogonally aligned hexagonal close-packed cylindrical structure are synthesized by dip coating silica precursors and poly(ethylene oxide)-polyproplyene oxide (PEO-PPO) triblock surfactants (P123) onto modified glass slides. All films cast from this sol display 2D hexagonal pore structures (a a?? 6.2 nm) under transmission electron microscopy (TEM). However, X-ray diffraction (XRD) shows that confining freshly deposited films between two chemically neutral modified slides completely aligns the pores toward the direction orthogonal to the substrate. Equally effective alignment is obtained by using slides modified with either a random PEO-PPO copolymer or P123 itself. The channels in films cast onto unmodified slides, onto modified slides which are exposed to air, or onto modified slides which are exposed to unmodified glass slides align at least partially parallel to the substrate. Parallel mesophase alignment is also observed in a control experiment with a sol containing the nonionic surfactant template decaethelyne glycol hexadecyl ether (Brij-56) sandwiched between copolymer-modified slides because the surfaces are not chemically neutral toward Brij-56. This study confirms that it is possible to use substrate surface chemistry to control the orientation of mesophases in mixtures of reactive silicates and low molecular weight nonionic surfactant templates. ? 2005 American Chemical Society.
Self-assembled-monolayer film islands as a self-patterned-mask for SiO2 thickness measurement with atomic force microscopy
Komeda,Namba,Nishioka
, p. 3398 - 3400 (1997)
A novel method for measuring ultrathin (2-12 nm) SiO2 film thickness is discussed. The process consists of: (1) formation of octadecyltrichlorosilane (OTS) self-assembled-monolayer (SAM) islands on SiO2 of which thickness to be measured, (2) removal of the SiO2 layers not covered by the OTS-SAM islands, and (3) measurement of the height difference between the etched and nonetched areas by atomic-force-microscopy. The OTS film is good resist against HF and its islands can be regarded as self-patterned-mask. Practical usefulness is demonstrated not only by the compatibility of the measured values but also by the short measurement period resulting from the -~-directness of the method.
Development of Highly Active Silica-Supported Nickel Phosphide Catalysts for Direct Dehydrogenative Conversion of Methane to Higher Hydrocarbons
Dipu, Arnoldus Lambertus,Nishikawa, Yuta,Inami, Yuta,Iguchi, Shoji,Yamanaka, Ichiro
, p. 199 - 212 (2022)
The direct dehydrogenative conversion of methane (DCM) to higher hydrocarbons was investigated over silica-supported nickel phosphide catalysts (NixPy/SiO2) over 1023?K. NixPy/SiO2 catalysts were prepared by precipitation method to promote formation of nickel phosphide (Ni2P) as an active phase for the DCM reaction. Characterization studies of the NixPy/SiO2 catalysts with different P/Ni molar ratios were conducted by a X-ray diffraction analysis, a H2-temperature-programmed reduction spectrum, a scanning electron microscopy image, a X-ray absorption spectroscopy and a N2-adsorption measurement. Catalytic activity tests for the DCM reaction were conducted using a conventional fixed-bed reactor. Products of C2H4 (ethylene), C2H6 (ethane), C2H2 (acetylene), C3H6 (propylene), C6H6 (benzene), C7H8 (toluene), C10H8 (naphthalene) and H2 were analyzed by GC-TCD and GC-FID instruments. Different degrees of the Ni2P phase and character were observed for the NixPy/SiO2 catalysts from characterization studies. Data from characterization studies indicated that smaller and dispersed Ni2P particles were obtained by precipitation method as compared to that of impregnation method. NixPy/SiO2 with a molar ratio of P/Ni = 3.0 showed optimum catalytic performance with 3.28% of methane conversion, 1.93% of total product yield, and 60% of selectivity to hydrocarbons. The experimental results of the effects of reaction temperatures on the product distributions and activation energies indicated that the Ni2P phase successfully activated the C–H bond of methane and selectively converted to ethane. Ethane thermally converted to other higher hydrocarbons in the gas phase without the participation of the catalyst. Graphic Abstract: [Figure not available: see fulltext.].
