A new soluble organic–inorganic hybrid based on polyoxomolybdate, [C6H12N5O]3[(PO4)Mo12O36]·6H2O (1), has been successfully synthesized and characterized by using elemental analysis, IR, UV spectroscopies, 1H NMR technique, and single-crystal X-ray diffraction. According to the results of X-ray crystallography the anion [(PO4)Mo12O36]3− has a typical Keggin structure and the Mo–O distances of Mo–O–Mo bonds are alternately short and long in the polyoxoanion structure. Hirshfeld surface analyses, especially dnorm surface and fingerprint plots, are used for decoding intermolecular interactions in the crystal network and contribution of component units for the construction of the 3D architecture. The results indicate that in 1 the hydrogen bond interaction play a main role in the construction of the 3D architecture, especially the CHO interaction which overruns the classic NHO, NHO hydrogen bond interactions; van der Waals force between the peripheral atoms of component units cannot be ignored. 相似文献
The thermal behavior of Illitic-kaolinitic clay for manufacturing of low porosity ceramic Raschig rings was characterized
during the sintering process. The samples were shaped by extrusion method and fired at different temperatures from 1,100 to
1,300 °C. The main physical-chemical transformations were studied by evaluating changes in shrinkage, water absorption, porosity,
mechanical strength, microstructure and mineralogical compositions. The optimum sintering condition was found to obtain maximum
mechanical strength. Chemical resistance of ceramic Raschig rings also was determined according standard method. It was shown
that the better chemical resistance could be attributed to the different mineralogical compositions, in particular with presence
of mullite phase. 相似文献
In this study, two different nano-silica particles (hydrophilic, Aerosil TT600 and hydrophobic, Aerosil R972) were selected in order to provide the most transparent, UV-absorbent nano-clearcoats. These nano-silica particles were used to improve and optimize properties of 2-pack polyurethane clearcoats based on acrylic polyol. Micro-PIXE analysis was employed to illustrate distribution of nano-silica in the polyurethane matrix. Physical and chemical degradations were investigated via spectrophotometry and FTIR spectroscopy.Additionally, thermal stability and the ability of the clearcoats to resist simulated car wash conditions were also studied. Contrary to belief, coatings loaded with hydrophilic nano-silica which are more UV-absorbent had less durability in UV-B/H2O accelerated tests. 相似文献
Inflammation has a fundamental impact on the pathophysiology of osteoarthritis (OA), a common form of degenerative arthritis. It has previously been established that curcumin, a component of turmeric (Curcuma longa), has anti-inflammatory properties. This research evaluates the potentials of curcumin on the pathophysiology of OA in vitro. To explore the anti-inflammatory efficacy of curcumin in an inflamed joint, an osteoarthritic environment (OA-EN) model consisting of fibroblasts, T-lymphocytes, 3D-chondrocytes is constructed and co-incubated with TNF-α, antisense oligonucleotides targeting NF-kB (ASO-NF-kB), or an IkB-kinase (IKK) inhibitor (BMS-345541). Our results show that OA-EN, similar to TNF-α, suppresses chondrocyte viability, which is accompanied by a significant decrease in cartilage-specific proteins (collagen II, CSPG, Sox9) and an increase in NF-kB-driven gene proteins participating in inflammation, apoptosis, and breakdown (NF-kB, MMP-9, Cox-2, Caspase-3). Conversely, similar to knockdown of NF-kB at the mRNA level or at the IKK level, curcumin suppresses NF-kB activation, NF-kB-promotes gene proteins derived from the OA-EN, and stimulates collagen II, CSPG, and Sox9 expression. Furthermore, co-immunoprecipitation assay shows that curcumin reduces OA-EN-mediated inflammation and chondrocyte apoptosis, with concomitant chondroprotective effects, due to modulation of Sox-9/NF-kB signaling axis. Finally, curcumin selectively hinders the interaction of p-NF-kB-p65 directly with DNA—this association is disrupted through DTT. These results suggest that curcumin suppresses inflammation in OA-EN via modulating NF-kB-Sox9 coupling and is essential for maintaining homeostasis in OA by balancing chondrocyte survival and inflammatory responses. This may contribute to the alternative treatment of OA with respect to the efficacy of curcumin. 相似文献
Since ZnO nanoparticles increase the electrical conductivity of the polypyrrole (PPy) coatings, an investigation was carried out to evaluate the effect of ZnO nanoparticles loading on the corrosion protection performance of PPy coatings on AA2024 Al alloy in 3.5% NaCl solution. At first, some measurements were carried out to find the best experimental conditions containing the electrodeposition method, electrosynthesis solvent composition, and ZnO nanoparticles’ concentration for preparing the optimum PPy coating on Al alloy2024. Three different methods of electrodeposition, namely: cyclic voltammetry, galvanostatic, and potentiostatic techniques were analyzed. The anti-corrosion performance of the PPy coatings was evaluated by electrochemical impedance spectroscopy and Tafel polarization methods. The PPy prepared by potentiostatic method exhibited the best performance against corrosion of Al alloy2024 in 3.5% NaCl solution. Then, different mixtures of H2O/ethanol were tested as electrosynthesis solvents for preparation of PPy coatings on the alloy by optimized electrodeposition mode (i.e., potentiostatic). In evaluation of the prepared coatings, the pure water was introduced as the optimum solvent in electrodeposition of PPy. The investigation of different ZnO nanoparticles’ concentrations proved that the PPy coating containing 0.025% ZnO nanoparticles was the optimum coating against the corrosion of Al alloy in NaCl solution. Finally, the long-term evaluation of the corrosion protection performance of the coatings revealed that the optimum coating provided suitable protection against corrosion up to 14 days after immersion.
Oxidative aromatization of 1,3,5-trisubstituted 2-pyrazolines by in-situ generation of NO+ from oxalic acid/sodium nitrite system has been described. The main advantages of this procedure are the use of an inexpensive and readily available catalyst, facile work-up, and improved yields in aqueous ethanol. 相似文献
In this investigation, a numerical technique to obtain the approximate solutions of four well‐known nonlinear differential equations in the area of heat transfer is presented. This method is based on the operational matrix of derivative of linear barycentric rational interpolation. The main advantages of this approach are that it uses the Floater‐Hormann weights, which are very efficient in practice, and reduces the governing differential equation to a system of algebraic equations. The results are compared with the obtained numerical results of the fourth‐order Runge‐Kutta method along with the shooting method and some of the previously existing methods. The acquired results reveal that the derivative operational matrix method with barycentric rational basis functions is very efficient and can be implemented easily and fast. 相似文献
A two-stage thermocatalytic upgrading process using a novel catalyst was investigated to produce light olefins and liquid fuels from fuel oil. The upgraded oil from the first thermal stage demonstrated lower viscosity and higher crackability compared to the virgin feedstock. In the next step, the vapor-phase catalytic cracking of the upgraded fraction was implemented over a novel nanoporous composite catalyst, characterized by the XRD, FTIR, NH3- TPD, and N2 physisorption techniques. In total, more than 55?wt% of light olefins, particularly propylene (25.5?wt%) together with 25.4?wt% and 32.5?wt% of gasoline and diesel fuel were obtained in this process. 相似文献