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Two novel molybdenum-based heterogeneous catalysts immobilized on dendrimer-functionalized graphene oxide via electrostatic interactions (Mo-1) or covalent bonding (Mo-2) are reported. The catalysts show excellent catalysis in epoxidation of alkenes with high conversion, better selectivity and good recyclability. The characteristics were identified by SEM, TEM (EDS-mapping), FT-IR, XRD, and XPS. The cause of the difference between the two catalysts is supported by DFT calculations.

Composite pile foundation has been widely used in ground engineering. This composite pile foundation system has complex pile-soil interactions under seismic loading. The calculation of vertical bearing capacity of composite pile foundation is still an unsolved problem if the soil around piles is partially or completely liquefied under seismic loading. We have completed indoor shaking table model tests to measure the vertical bearing capacity in a liquefiable soil foundation under seismic loading. This paper will use a numerical approach to analyze the change of this vertical bearing capacity under seismic loading. Firstly, the Goodman contact element is improved to include the Rayleigh damping. Such an improvement can well describe the reflection and absorption of seismic waves at the interface of soil and piles. Secondly, the Biot’s dynamic consolidation theory incorporated an elastoplastic model is applied to simulate the soil deformation and the generation and accumulation of pore water pressure under seismic loading. Thirdly, after verification with our indoor shaking table test data, this approach is used to investigate the effects of pile spacing on liquefaction resistance of the composite pile foundation in liquefiable soil. The time histories of pore water pressure ratio (PPR′) are calculated for the liquefiable soil and the vertical bearing capacity in partially liquefied soil is calculated and compared with our indoor shaking table test data at the 3D, 3.5D, 4D, 5D and 6D cases (D is the pile diameter). It is found that the pile spacing has some influence on the extent of soil liquefaction between piles. The vertical bearing capacity varies with liquefaction extent of inter-pile soil. The optimization of pile spacing varies with liquefaction extent. These results may provide some reference for the design of composite pile foundation under seismic loading.

In this precent study, microstructure evolution of a newly developed 690 MPa composite microalloyed anti-seismic fire-resistant steel plate after quenching at 740 °C , quenching at 740 °C + tempering at 400 °C were studied and the fire resistance mechanism was analyzed. Experimental results show that the microstructure of hot rolled state of the tested steel is lath martensite, acicular ferrite, bainite and M/A island. After quenching at 740 °C, the microstructure of steel was composed of lath martensite, polygonal ferrite and retained austenite. The mixed microstructure of tempered troostite + bainite + a small amount of M/A island was obtained after quenching at 740 °C + tempering at 400 °C , it transforms into tempered sorbite + bainite after holding at 600 °C for 3h. A great number of fine carbides containing Mo, Nb, V and Ti precipitate at 600 °C of the quenched + tempered state of tested steel. The mixed microstructure and fine composite carbides make the quenched +tempered steel have excellent fire resistance.

A label-free immunosensor was developed to detect the presence of an antigen. This immunosensor was based on the modulation of the electrochemistry of the surface bound redox species thionine (Thi). The model antigen was carcinoembryonic antigen (CEA) and the model epitope was the antibody of CEA (anti-CEA). Glassy carbon electrode surfaces were first drop-coated with a mixture of graphene, Thi and Nafion and air-dried. The electrode surface was then electrodeposited in HAuCl4solution to form Au nanoparticles (AuNPs). The resulted AuNPs were used to immobilize anti-CEA. Binding of CEA to the surface bound epitope resulted in the attenuation of the Thi electrochemistry. Under optimal conditions, the response of the label-free immunosensor had a liner range from 10 fg/mL to 100 ng/mL with a detection of 3.5 fg/mL (S/N=3).

Spindle-like hollow mesoporous silica nanoparticles (spindle-like HMSNs) were fabricated via the template-sacrificial technique using hematite (Fe2O3) spindles as hard template, tetraethylorthosilicate (TEOS) as precursor and cetyltrimethyl ammonium bromide (CTAB) as the pore directing agent. The Fe2O3core and CTAB were selectively removed by hydrochoric acid aqueous solution etching. Transmission electron microscopy results revealed that spindle-like HMSNs with thickness of shell range from 8 to 47 nm were prepared by changing the concentration of the reactant. This methodology provides a facile and robust route for preparation of hollow mesoporous materials.

In this paper, an attempt has been made to study the dynamic mechanic properties of vulcanized rubber material which is used for industrial structure. A split Hopkinson pressure bar (SHPB) is utilized to obtain uniaxial compression response of the vulcanized rubber material under different strain-rate and temperatures loading conditions. The stress-strain curves under different conditions are obtained, which can be used as a basis for the data analysis procedure. It is found that the dynamic compressive strength of vulcanized rubber improves with the increase of strain-rate. And it is also significantly higher at low temperature than that at normal temperature，which is opposite from stiffness. Vulcanized rubber exhibits excellent superelasticity at temperature of -40°C that is noted as well.

A series of plate impact experiments have been conducted on alumina specimens with different thicknesses through the light gas gun in order to further investigate the delayed failure phenomenon under shock loading. With the aid of the velocity interferometer system for any reflector, an evident recompression signal has been observed in the temporal curve of the rear free surface velocity of the specimen, which indicates the generation of the failure wave. According to the experimental results, the failure wave propagation was probed. The results show that the failure wave generates a delayed time of ∼0·105 μs behind the shock wave front and propagates into the stressed body with a velocity of ∼5051 m s−1 under the impact stress of 7·16 GPa. The physical mechanism of the failure wave was further discussed.

The joint technics on sodium jarosite process and solvent extraction technique for lixivium of nickel laterite ores has been investigated. The results indicate that a Fe2O3 product with Fe grade of 58.12% could be obtained by precipitation separation and roasting, the total recovery of iron reaches 94.87%.Under the conditions of extracting temperature for 30°C, phase ratio 1:1, blance time 10min, pH = 5.5, the percentage extraction rate of Ni reaches 99.04%. When the 3 mol/L H2SO4 solution was used as stripping agent, the stripping rate of Ni reaches 97.52%. The total recovery of nickel reaches 94.56%.

Adding fly ash to recycled concrete with super-substitute technique, comparing the 28d strength of fly ash recycled concrete(FARC) with the 28d strength of ordinary recycled concrete(ORC), the compressive strength of fly ash recycled concrete slightly decreased with the increase of the fly ash and the admixture of renewable aggregate. Along with the increase of mixing amount of the air entraining and water-reducing agent, the compressive strength of fly ash recycled concrete tends to reduce. The order of the factors that affect the chloride ion diffusion coefficient of recycled concrete is fly ash admixture→mixing amount of the air entraining and water-reducing agent→admixture of recycled coarse aggregate→polypropylene fibre admixture, which provides a basis for the application of recycled concrete engineering in the environment which is affected by chlorine salt in the north frigid area .

In this paper, the precursors were synthesized by microwave hydrothermal method using SnCl4•5H2O and Ce(NO3)3·6H2O as raw material, CO(NH2)2 as precipitants, respectively. Pure SnO2 nanoparticles and cerium-doped SnO2 nanoparticles were obtained. Furthermore, five kinds of SnO2 thick film gas sensors were fabricated from the above SnO2 nanoparticles (the sensors denoted as sensor SC0, SC2, SC3, SC4 and SC6, respectively). The experiment results showed that, compared with pure SnO2 thick film gas sensor, the intrinsic resistance of cerium-doped SnO2 thick film gas sensors decreased, and their sensor responses to acetone vapor increased, which are discussed in relation to the SEM micrographs of thick film sensors.

Using orthogonal test, the influence of variable mixing proportions of recycled coarse aggregate, polypropylene fibre and air entraining and water-reducing admixture on the anti-penetration capability of chloride ion of recycled concrete is analyzed. And the mechanism of resistance to chloride ion permeation concerning different mixing proportions of the materials is figured out. After that, basing on the effects of these materials on the durability life of recycled concrete in chlorate surroundings, the sequence is worked out: first, air entraining and water reducing agent, then recycled coarse aggregate, last one, polypropylene fibre. Employing Fick’s second law, the durability life of recycled concrete applied in chlorate environment is estimated. As a result, evidences for the practical application of recycled concrete are provided for its use in the northern cold areas and the places along the coast.

At present, there are not any systematic researches on the fundamental performance of recycled concrete(RC). Thus it incites the inadequate confidence for the usage of RC. In this thesis, four different kinds of RC whose strength are C20、C25、C30、C35 respectively,are made using various mixing proportion. Then the influence rule of different recycled aggregate mixture quantities is drawn out, which consists the impacts on compressive strength, axial compressive strength, splitting strength, elastic modulus as well as the bending strength of RC. Meanwhile, the relation between the cubic compressive strength and the splitting strength, elastic modulus, axial compressive strength, bending strength is imitated, which provides study basis for the using of wasted concrete.

Iron ore reduction and carbon deposition under H2-CO mixtures were investigated by using the non-isothermal method. Iron ore in three different configurations were used in this work: pellet, coarse granularity particles and fine granularity particles. The reduced samples were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and accelerated surface area and porosimetry System(ASAP 2020M+C). In pure CO, the carbon deposition increases with decreasing of the sample size. In H2-CO mixtures, the rate of carbon deposition is accelerated dramatically. Morphologies of samples treated in different reducing ambinent were investigated. Specific surface area of the treated sample increases with higher level of carbon deposition.

The sintering behavior, physical properties and heat processing changes of bauxite-based homogenized grogs prepared by homogenization process and high temperature sintering using bauxite as starting material were investigated. Results show that the bauxite-based mullite can be synthesized by the method, sintering temperature with and without MgO/CeO2sintering aids are 1600°C and 1700°C separately, the mullite with apparent porosity of＜1.0% and 2.5%, bulk density of ≥2.87g•cm-3and 2.75g•cm-3, Refracteriness-Under-Load(RUL) 1600°C and 1620С; changes in the heat processing is divided into three stages: dehydration stage(400°С~900°С ), primary mullitization stage(1000°С ~1200°С) and secondary mullitization stage(>1200°С).

Based on CT imaging theory and self-designed loading device, the CT real-time scanning test on recycled concrete under uniaxial static compression has been accomplished, which can be used to specifically study the whole process about microcrack initiation, perforation, coalescence and macrocrack generation in meso-scale. By real-time CT scanning of cylinder recycled concrete specimen, the propagation process of the internal cracks can be effectively tracked during the whole loading process. By extracting and analyzing the CT numbers of CT images under different loading period, the relational expression between CT numbers and deterioration variable was established, which can better reflect the effect of mixing amount of recycled coarse aggregate on deterioration degree of recycled concrete. The results showed that with the increasing mixing amount of recycled coarse aggregate, the deterioration degree of the specimens increased slightly yet uniaxial compression strength of the specimens decreased slightly.

Monodisperse ellipsoids were synthesized by continuous coating of silica on hematite spindle cores. Spindle cores with decreasing aspect ratio were obtained by decreasing the molar ratio of Fe 3+ and H 2 PO 4 − . Using PVP molecules as the surface stabilizer for silica coating, the aspect ratio of the ellipsoids can also be tuned by altering the amount of added TEOS. These monodisperse ellipsoids with well controlled sizes and aspect ratios can be regarded as the potential building blocks for self-assembly.

The corrosion can be widely found in metal materials, which greatly restricts the utilization of metal. Super-hydrophobic coating, known as a material surface with a contact angle greater than 150°, which has been gradually used as a protect film on the surface of metallic material in recent studies. The article presents a review of recent literatures which covers aspects of using super-hydrophobic film as a smart protect surface to protect metallic materials. Different super-hydrophobic systems obtained by different preparation technologies were introduced in this work. Overall, the obtained results indicate that the super-hydrophobic coatings can effectively enhance the anti-corrosion ability of the metal surface, which supports the possibility of using super-hydrophobic film as a substitute of chromate-containing passivation coatings to protect metallic substrates.

The failure wave phenomenon was interpreted in glass media under the high velocity impact with the stress levels below the Hugoniot elastic limit. In view of the plate impact experimental observations a damage-accumulating model predominated by the deviatoric stress impulse was proposed while Heaviside function was adopted in the damage-accumulating model to describe the failure delay in the interior of materials. Features of the failure layer and propagation mechanism as well as their dynamic characteristics were further presented. The reduction in failure wave propagation speed is pointed out as the reflected rarefaction waves reflect again from the failure layer boundary.

With the porous media model based on mixture theory, a finite element formulation for dynamic transient analysis of fluid-saturated two-phase porous media is presented. Time integration of the equation, deduced with penalty method, can be performed by using implicit or explicit method. One-dimensional wave propagation in column under step loading and impulsive loading are analyzed with the developed finite element program. The obtained curves of displacements, velocities, effective stresses and pore pressures against time demonstrate the existence of wave propagation phenomena, which coincide with the theoretical results.

Three-dimensional photonic crystals (or photonic band gap materials) have been fabricated with oblate spheroids as the photonic building block. The nonspherical shape was realized by the blown film extrusion process of a prefabricated colloidal photonic crystal of spherical polystyrene particles, with its voids infiltrated by polyvinyl alcohol. The extrusion was applied on the composite film at a temperature above the glass transition temperature of both polymers. The uniformly applied two-dimensional stretching retains the positional order in the prefabricated colloidal crystal; transforms the spheres into oblate spheroids; and results in orientational order between the spheroids. The morphology of the particles can be predictably changed from a sphere into an oblate spheroid with a specified aspect ratio by the extent of the blown film extrusion. Therefore, the concomitant photonic band gap properties can be tuned in a convenient way.

A ternary system, consisting of air, an air-core/dense-silica-shell core−shell particle, and liquids has been used to fabricate an inverse opal structure with low fill factor, high refractive index contrast, and reversible tuning capabilities of the bandgap spectral position. The original close-packed opal structure is a ternary self-assembled photonic crystal from monodisperse and spherical polystyrene-core/silica-shell colloidal particles with air as the void material. Calcination removed the polystyrene and converted the core−shell particles to hollow spheres with a dense shell. In a final step, liquid is infiltrated only in the voids between the hollow spheres, but does not penetrate in the shell. This allows facile and reversible tuning of the bandgap properties in an inverse opal structure.