In order to improve the thermal shock resistance of solar thermal heat transfer tube material, the mullite-cordierite composite ceramic as solar thermal heat transfer tube material were fabricated by pressureless sintering using α-Al₂O₃, Suzhou kaolin, talc, and feldspar as starting materials. The important parameter for solar thermal transfer tube such as water absorption (W _a), bulk density (D _b), and the mechanical properties were investigated. The phase composition and microstructure of the composite ceramics were analyzed by XRD and SEM. The experimental results show that the B3 sintered at 1 300 °C and holding for 3 h has an optimum thermal shock resistance. The bending strength loss rate of B3 is only 2% at 1 100°C by air quenching-strength test and the sample can endure 30 times thermal shock cycling, and the water absorption the bulk density and bending strength are 0.32%, 2.58 g·cm⁻³, and 125.59 MPa respectively. The XRD analysis indicated that the phase compositions of the sample were mullite, cordierite, corundum, and spinel. The SEM images illustrate that the cordierite is prismatic grain and the mullite is nano rod, showing a good thermal shock resistance for composite ceramics as potential solar thermal power material.

Co-precipitation compound precursors-hydrothermal processing was employed to synthesize Ni/Cu/Al₂O₃/ZrO₂ composite powder, and ZrO₂-based composite ceramics was prepared. The technology recycled the metal of nickel, copper and aluminum from sludge, and the recovery rate of nickel was up to 95.5%. The property of ZrO₂-based composite ceramics was improved because of the existence of nickel and copper particles. The fracture toughness of Ni/Cu/Al₂O₃/ZrO₂ composite ceramics was 8.52 MPa·m^1/2 and the compressive strength was 51 MPa, showing the increase by 2.54 times and 1.5 times, respectively, compared with those of pure ZrO₂ ceramics.

The bulk Ti₃SiC₂ specimens with less than 1 wt% TiC impurity were prepared by vacuum sintering technique, and the average grain size was about 5–6 μm in the elongated direction. When the sintering temperature, soaking time and heating rate were 1 400 °C, 1 h and 10 °C·min⁻¹, respectively, the highest relative density of Ti₃SiC₂ specimens could reach 97.8%. Meanwhile, the lowest coefficient of friction (COF) and wear rate (WR) of the Ti₃SiC₂ samples were 0.55 and 1.37×10⁻³ mm³(Nm)⁻¹ at a sliding speed of 0.35 m/s, load pressure of 10 N and ambient condition, respectively. The COF of the Ti₃SiC₂ sample reduced with the increasing of the load pressure, while the WRs fluctuated little. The WR increased with the increasing of the sliding speed, and weakly influenced the COF. These changing behaviors could be attributed to the presence and coverage of the amorphous mixture oxide film of Ti, Si, Al, and Fe on the Ti₃SiC₂ friction surface. The self-antifriction mechanism led to reducing of the COF. The increasing of the WR was attributed to the wearing consumption.

The semi-terminated silica nanotubes with 80–100 nm porous diameter were prepared with Al/Al₂O₃ (AAO) template by the sol-gel method, and then were functionalized by 3-aminopropyltriethoxysilane (APTES). The functionalized silica nanotubes were characterized by transmission electron microscope (TEM), fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (¹H-NMR and ²⁹Si-NMR). The results indicated that APTES was successfully functionalized onto the internal surface and the mouth of the silica nanotubes. It would provide the material base for silica nanotubes corking and delivery drug.

Nickel-coated graphite particles and two-component silicone-rubber were compounded to form a conductive composite system. The electrical volume resistivity of the composites were examined and compared under constant tensile strains, cyclic heating-cooling, electric field and repeated cyclic tensile strains in order to study the mechanism of electrical conductivity behaviors of the conductive composites under stress, temperature and current. The results showed that a peak value of the electrical resistivity appeared previously and then gradually increasing with increasing tensile strain. The electrical resistivity displayed positive temperature coefficient effect during the temperature increasing and decreasing. Applying 5A direct current to the conductive composites resulted in an increase in the electrical resistance immediately, but no changes were detected under lower currents. Under the repeated cyclic strain, the peak value of the electrical resistivity of each cycle increased with the test cycle. All the electrical resistivity changes were attributed to the conductive networks broken-up and rebuilt in the conductive composites.

A mixture of NiCrSiB alloy powder and tantalum (Ta) powder was used as laser clad material to improve abrasive wear resistance of the Ni-based coating. The microstructure and wear resistance of the coating were investigated. Addition of Ta element works to suppress the growth of coarse M₇C₃ carbide in the coating, resulting in a decrease in aspect ratio of coarse carbide. In the abrasive wear test, in situ synthesized TaC particles well bond with Ni-based matrix, and are hardly pull out from wear surface. Grooves on the worn surface of NiCrSiB coating are much deeper and sharper than those in the NiCrSiB+Ta composite coating. Also, a weight loss of the composite coating is much lower than that of the NiCrSiB coating. The wear resistance of the laser clad Ni-based coating is enhanced to a much greater extent through the addition of Ta. This is attributed to the in situ synthesized hard TaC particles of nearly equiaxed shape, the Ni-based matrix strengthened by Ta and the decrease in aspect ratio of the coarse brittle carbides.

Silicon-doped diamond-like carbon (Si-DLC) films possess the potential to improve wear performance of DLC films in humid atmospheres and at higher temperatures. But many experimental results of Si-DLC films show that their structure and mechanical properties have changed greatly with the increasing silicon content. Therefore, molecular dynamics (MD) simulations were used to generate hydrogen-free Si-DLC films and study their nano-indentation process under the interaction of a diamond indenter. The results show that sp ³/sp ²(C) (only carbon atoms) always decreases with the increasing silicon content. But sp ³/sp ²(C+Si) ratio increases firstly and reaches a maximum at the silicon content of 0.2, and then decreases with the further increase of the silicon content. Bulk modulus and hardness of the Si-DLC films both decrease with the increasing of the silicon content, which has the same trend with Papakonstantinou and Ikeyama’s results. It is concluded that the hardness of the Si-DLC films is dependent on sp ³/sp ²(C), not sp ³/sp ²(C+Si).

Tungsten carbide (WC) particles can be in-situ synthesized through the reaction between tungsten wires and molten of gray cast iron. The different composite coatings were obtained by adjusting the pouring temperature and the center distance of tungsten wires, and were comparatively observed by X-ray diffraction, scanning electron microscopy, and two-body abrasive wear tests. The results show that the intensities of the WC peaks increase by the increasing pouring temperature, and firstly become strong and then weak by the increasing center distance. In case of the pouring temperature 1 400 °C and the center distance 0.5 mm, the formed WC particles present quadrilateral and triangle-structure and are homogenously distributed in the matrix. The wear rate of the composite coatings for stable center distance gradually increases by increasing the loads, however, at a constant pouring temperature, it firstly decreases from 5.91 to 2.97 mg/cm²·h, and slightly increases to 3.98 mg/cm²·h by increasing the center distance.

The Pr³⁺-Yb³⁺ co-doped oxyfluoride glass-ceramics containing CaF₂ nanocrystals were obtained by thermal treatment on the as-made glasses. The structure of fluoride nanocrystals was investigated. The light-emitting mechanism of Pr³⁺-Yb³⁺ in the near infrared region was proposed and the fluorescence lifetime and quantum efficiency was calculated. The results indicate that the main phase in the oxyfluoride glassceramics is CaF₂ nanocrystal sized at 30 nm. Energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) have proved the incorporation of Pr³⁺ and Yb³⁺ into CaF₂ nanocrystal lattice. Near-infrared quantum cutting involving Yb³⁺ 980 nm and 1 015 nm (²F_5/2→² F _7/2) emission has been achieved upon the excitation of the ³ P ₀ energy level of Pr³⁺ at 482 nm. The fluorescence lifetime decreases sharply and quantum efficiency increases with increasing Yb³⁺ concentration, and the optimal quantum efficiency reaches 191%.

The aim of this work is optimizing the techniques to prepare pure cellulose microspheres, which are used as packing adsorbents for high-performance liquid chromatography. Thereupon, cellulose was dissolved in a pre-cooled NaOH/urea solution, from which various-size microspheres were prepared. The volume-average diameters were controlled approximately at 30 μm, 8 μm and 4 μm grades when cyclohexane, liquid paraffin and pump oil were used as dispersants, respectively. The present investigations reveal that higher viscosity dispersant is suitable for the preparation of smaller-size microspheres, while larger size microspheres are prepared preferably using lower-viscosity dispersant. The chiral stationary phase derived from 8 μm grade microspheres can separate the enantiomers of efavirenz.

Memory effect has been studied in the system using magnetic nanoparticles with Ni nanocore encapsulated by non-magnetic and oxidation-resistant Ni₂P nanoshell acquired through surface-phosphatizing Ni nanoparticles. The self-assembled array with interparticle spacing of about 6 nm shows memory effect up to 200 K below its average blocking temperature of 260 K. And reducing the interparticle spacing of the self-assembled array via annealing can further enlarge the temperature range of memory effect up to room-temperature. The memory effect can be understood based on the thermal relaxation theory of single-domain magnetic nanoparticles. Furthermore, the read-write magnetic coding is realized based on the temperature changes, using the memory effect up to room-temperature, which may be useful for future memory devices.

Mullite whiskers were facilely prepared by sintering kyanite at high temperature, with the addition of AlF₃·3H₂O. The as-prepared whiskers have been characterized systematically in terms of phase composition, morphology, and structure. Results showed that the morphology and size of mullite whiskers were strongly depended on the content of AlF₃·3H₂O and sintering temperature. At temperatures in the range of 1 100 to 1 500°C with 4 wt% addition of AlF₃·3H₂O, the well-shaped mullite whiskers were obtained. For an instance, the mullite whiskers with 5–10 μm in length and 0.1–0.2 μm in cross-section could be formed at 1 400°C, with 4 wt% addition of AlF₃·3H₂O. Moreover, results showed that the addition of mullite whiskers into ceramic matrix enhanced its fracture toughness significantly.

Chemical modification/ambient drying method and freeze drying method were introduced to research the synthesis of mesoporous silica aerogels. By analyzing N₂ gas adsorption/desorption isotherms, the fractal geometric characteristics of gels were focused. The overall surface fractal dimensions were determined by analyzing N₂ gas adsorption branch and a Frenkel-Halsey-Hill (FHH) equation was empolyed to determine surface fractal dimension D _f. It is found that, during ambient drying process, V _TMCS/V _Wetgel ratio plays a crucial role in the changes of geometric feature, the key point is 50%, when the ratio is lower, and surface roughness increases with the ratio, when it exceeds 50%, the surface is almost unaffected by the modification. While freeze drying always tends to get larger D _f, freeze drying process could cause a rough surface of the gels. Compared with traditional porosity and specific surface area analyses, fractal geometry may be expected to be favorable for mesoporous structural analyses of materials.

ZrO₂-MgO-Y₂O₃-CaO-Al₂O₃ composites with a multiphase microstructure were fabricated by die pressing process and sintered at various thermal programs. The microstructure of this polycrystalline was examined to clarify the role of Al₂O₃ on grain growth. Environmental scanning electron microscopy (ESEM) micrographs revealed that spinel was beneficial to refine grain. The effect of thermal treatment on the formation of monoclinic phase was discussed. It can be found that, the grain size and the fraction of the monoclinic phase in this partially stabilized zirconia(PSZ) increases after heat treatment at 1 150 °C. The temperature of heat-treatment, not the time for holding, is the governing factor of the fraction of monoclinic phase.

The influence of temperature on the engineered properties of bentonite-sand mixtures (B/S) is of major concern in the design of engineered barriers in underground repositories for high-level radioactive waste disposal. We experimentally studied the influence of temperature on soil unsaturated hydraulic properties related to water holding capacity and permeability of GMZ B/S in China. The vapor equilibrium method and water infiltration apparatus were used to measure the soil water characteristic curve (SWCC) and unsaturated hydraulic conductivity (k _u). The results show that the SWCC under different temperatures from 20 °C to 60 °C tends to be the same. Temperature influence on unsaturated permeability is more relevant at low suctions, no clear effect is detected below a degree of saturation of 74%, and experimental data show that temperature dependence on unsaturated permeability is small.

To make better use of 2.5D C/SiC composites in industry, it is necessary to understand the mechanical properties. A finite element model of 2.5D composites is established, by considering the fiber undulation and the porosity in 2.5D C/SiC composites. The fiber direction of warp is defined by cosine function to simulate the undulation of warp, and based on uniform strain assumption, analytical model of the elastic modulus and coefficient of thermal expansion (CTE) for 2.5D C/SiC composites were established by using dualscale model. The result is found to correlate reasonably well with the predicted results and experimental results. The parametric study also demonstrates the effects of the fiber volume fraction, distance of warp yarn, and porosity in micro-scale on the mechanical properties and the coefficients of thermal expansion.

The synthesis and characterization of Fe-doped CuAlO₂ semiconductor were reported. The samples were synthesized by a simple and cost effective spin-on technique from solid state reaction of Cu₂O and Al₂O₃ on sapphire (001) substrate. Appropriate ethyl-cellulose (EC) and terpineol are useful for the formation of Fe-doped CuAlO₂ films. X-ray diffraction (XRD) revealed the growth of pure delafossite CuAlO₂ phase ruled out elemental metallic Fe clusters in all the Fe incorporated CuAlO₂ films. The existence of ferromagnetism at room temperature is evidenced by well-defined hysteresis loops. Specially, the saturation magnetization (M _s) values at room temperature have been monotonously enhanced with the increase of Fe composition from 1% to 5%.

Cu/Ti₂AlC composites were fabricated by vacuum hot-pressing technique. Phase composition was analyzed by XRD and morphology of fracture was observed by SEM. Physical performance such as density, resistivity, hardness and friction coefficient with different volume fraction of Cu/Ti₂AlC composites were studied. When the content of Ti₂AlC increased from 10% to 70%, the relative density reduced from 99.38% to 90.56% and the resistivity increased significantly. Hardness reached the maximum value when Ti₂AlC was at 60% and friction coefficient declined with the increasing of Ti₂AlC. Cu/Ti₂AlC composites, showing good conductivity properties and friction performance. Oxidation resistance enhanced obviously with the content of Ti₂AlC increasing. Cu-60%Ti₂AlC sample possessed optimum thermal shock resistance, and no cracking was found at 600 °C cycled for 10 times and 900 °C cycled for 1 time.

The bonding mechanism between straw and concrete was analyzed through testing the compressive strength and flexural strength of hollow block, with different straw amount and different dosage and types of admixtures. The test results show that the mechanical properties of hollow blocks reduced after adding straws, and the more straws was added, the more hollow block density decreased. But adding Al₂(SO₄)₃ and CaCl₂ could improve the dense degree between rice straw and concrete. And when the proportion of straw mixing amount was 10%, the flexural strength of the early strength agent (2% Al₂(SO₄)₃, CaCl₂) added hollow block reached as maximal as 3.1 MPa, while the compressive strength was 9.1 MPa, consisting with the strength grade of common concrete hollow block MU7.5.

The mechanical properties are essentially different when rock material is subjected to loading or unloading conditions. In this study, loading and unloading tests with various confining pressures are conducted to investigate the mechanical properties of marble material samples taken from the deep diversion tunnels of Jinping II Hydropower Station. The stress-strain relationship, failure characteristics and strength criterion are compared and analyzed based on the experiment results. The results show: in the loading and unloading test, peak strength, lateral strain, axial strain and plastic deformation increase significantly as the confining pressure increases. Lateral strain increased significantly and obvious lateral dilatancy can be observed to the change of confining pressure; The fracture mode is mainly the single shear fracture for the triaxial compression test and post-peak test, angle between the failure surface and the ends of the rock material becomes smaller as the confining pressure increases. Hoek-Brown strength criterion reflects the strength characteristics of marble material under two different unloading conditions, and has some supplementary effects to the rock material of mechanical field.

Phosphogypsum-slag-clink (PSC) cement were prepared by original phosphogypsum(PG), which was grinded after dried at 60 °C combined with different contents of phosphogypsum (15%, 20%, 30%), and a small amount of different C₃A, C₄AF contents of finely ground cement clinker, and ground granulated blast furnace slag (GGBFS). Physical mechanical and sugaring properties were studied. The results show that compressive strength of PSC cement with 20% phosphogypsum at 3 d ages would be higher than 17 MPa and even 50 MPa at 28 days. Compressive strength at longer curing stage and sugaring properties of PSC with lower content of C₃A higher C₄AF clinker were improved. pH value of PSC cement system at early stage was relatively low, and pH gradually increased with the addition of clinker. pH increased firstly and then decreased with the hydration stage. SEM analyses showed that the amount of ettringite, which was influenced by pH and content of Al, must be controlled in PSC cement system, which may cause damage to microstructure or even expansive cracks if large amount of ettringite formed in hardened paste.

To obtain the fracture parameters of concrete, fracture tests were conducted with three-point bending beam method aiming at 30 concrete beams with different sizes and different intensity. The concrete specimen with prefabricated crack to determine the fracture parameters of concrete were conducted and the fracture performance of the specimen was analyzed. The test results show that, initial fracture toughness is unrelated to the size of specimens; while unstable fracture toughness is related to the size of specimens. As for specimens of bastard size, when concrete intensity is relatively low, unstable fracture toughness increases along with the increase of intensity; when concrete intensity is relatively high, unstable fracture toughness will decrease; when concrete intensity increases continuously, unstable fracture toughness will further increase somewhat. As for specimens of standard size, unstable fracture toughness will increase along with the increase of intensity. Aiming at concrete beam specimens, we conducted two-dimensional non-linear finite element analysis, obtained the stress intensity factor, and carried out contrastive analysis with the experimental results.

Phosphogypsum(PG) calcined at 500 °C was activated by K₂SO₄ and salt lime with loose structure as seed crystal. To determine the effect of activation, hydration of the anhydrate PG activated was investigated by examination of the setting time, the proportion of hydrated anhydrate PG, the microstructure of the hardenite and the resistance to water. Results show that activated anhydrate PG hydrates much more rapidly than that in the absence of activators. The activated anhydrate PG has proper setting time and hydrated proportion. The resistance to water was greatly improved. SEM photos show that the set activated PG has hydrated products of rod-like and closely connected crystals. The different addition of activator leads to different compact structure.

We studied the corrosion characteristics of reinforcing bars in concrete under different corrosion conditions. The area-box (AB) value was used to classify the shape of pitting corrosion morphology in meso-scale, and fractographs of reinforcing bars with different corrosion morphology were discussed in micro- and macro-scales. The results show that the existence of the tensile stress affects the corrosion characteristics of reinforcing bars. The pitting morphology and fractograph of reinforcing bars exhibit a statistical fractal feature. The linear regression model fits the relationship between fractal dimensions of corrosion morphology and fractal dimension of fractograph fairly well. Using fractal dimension as the characterization parameter can not only reflect the characteristics of pitting corrosion morphology in reinforcing bars, but also reveal the fracture feature of corroded reinforcing bars.

Porous haydite used as waste filter medium was prepared by dreging lake sludge to help solve the treatment problem of sludge and realize its reclamation. Several calcination regimes were considered and their effects on the pore structure and the properties such as the strength, the density, the filtering ability and the phosphate absorption ability of the haydite were investigated. For the mixture of 60% lake sludge and 40% fly ash in this experiment, the calcination regime with a pre-calcination period at about 600 °C, a temperature keeping period at 1 200 °C and a moderate cooling rate are recommended to prepare haydite with reasonable pore structure and good performances for its usage as the waste water filter media.

Chloride binding is often described by chloride binding isotherm, which is closely related to the service life of concrete structures in chloride environments. Many methods have been proposed to determine chloride binding isotherm. Compared to other methods, chloride binding isotherms obtained directly from nonsteady-state diffusion tests seem closer to the reality. We studied the chloride binding isotherm from both nonsteady-state electrical-accelerated migration and diffusion tests at different temperatures. Twelve concrete mixes with different supplementary cementing materials and water-to-binder ratios of 0.35, 0.48 and 0.6 were cast for study. The specimens after diffusion (or migration) tests were sliced layer by layer, and acid-soluble and free chloride contents of each layer were measured. A chloride binding isotherm was obtained from one specimen. Experimental results indicated that electrical voltage had a slight effect on the chloride binding isotherm of concrete. Temperature had a positive effect on chloride binding. The higher the water-to-binder ratio was, the higher the chloride binding was.

Modified asphalt binders were prepared by adding conductive materials, graphite and carbon fiber. The rotation thin film oven test (RTFOT) and pressure age vessel test (PAV) were conducted to simulate the binder aging in the field. Rheological properties of graphite and carbon fiber modified asphalt binder were investigated by the empirically rheological properties (penetration and softening point) and the dynamic shear rheometer (DSR) test. Results show that physical properties of asphalt binder change with conductive material mixed. DSR tests present that the values of complex modulus increase while phase angles decrease under a proper amount of graphite and carbon fiber. Rutting parameters point out that graphite can improve the rutting resistance of asphalts. Rheological parameters can be used to assess aging.

To study the applicability of the basalt fiber through various experimental works in thermal and chemical environments, glass fiber and carbon fiber were compared and discussed. The tensile strength testing was used to investigate the corrosive resistance of basalt fiber, meanwhile, surface study by scanning electron microscopy and microanalysis with complementary X-ray diffraction analysis (SEM/EDS) was also used to ascertain the durability of basalt fiber. The basalt fiber showed better strength retention than the glass fiber at relatively high temperature. Its tensile strength increased when exposed at 300 °C for several hours, and still maintain about 70% of the initial strength at 400 °C, whereas that of the glass fiber decreased dramatically. The better stability of the basalt fiber was observed in hydrothermal and chemical environment. The tensile strength of the basalt fiber increased by 20% after the immersion in boiling water and remained well in acid solution, when it comes to glass fiber, the tensile strength decreased to some extent. Although the alkali resistance of basalt fiber was poor at the initial stage, it shows better resistance than the glass fiber after long time treatment.

A 2-acrylamide-2-methyl propylene sodium sulfonic (AMPS)-modified polyacrylic acid superplasticizer was synthesized using aqueous solution polymerization with the major monomers including the self-made active macromers polyethylene glycol mono-methyl ether acrylate acrylic (MPEGAA), acrylic acid (AA), AMPS, and sodium methyl allyl sulfonate (SMAS). The ratios of the monomers were determined using an orthogonal experiment. This research focused on the effects of the dosages of different macromers, the polymerization conditions, and the length of MPEGAA side chains on the properties of the AMPS-modified polyacrylic acid superplasticizer. The best polymerization conditions of the AMPS-modified polyacrylic acid superplasticizer are when (n(MPEGAA):n(SMAS):n(AMPS):n(AA) equals 0.1:0.1:0.2:0.65, the molecular weight of monomethoxypolyethylene glycol is 1 200, the initiator ammonium persulfate accounts for 5% of the total mass of the polymerized monomers, the polymerization temperature is 80 °C, and the reaction time is 4 h. The AMPS-modified polyacrylic acid superplasticizer synthesized in the best conditions exhibited excellent dispersivity and dispersion retainability. When the dosage ratio was 0.24%, the initial fluidity was 400 mm and the fluidity had nearly no loss after 1 h.

Different doses of electron beam was imposed on the polyacrylonitrile(PAN) precursor fibers before the fibers were stabilized. The effect of electron beam irradiation on the chemical structure, crystallite size of PAN precursor fibers and density, oxygen content, transverse section morphology of the stabilized fibers in the stabilization process were characterized by the use of fourier transform infrared spectroscopy(FTIR), float-sink procedure, elemental analysis and scanning electron microscope(SEM), respectively. The results showed that the extent of cyclization was increased and the crystallite size was decreased. We found that electron beam irradiation could accelerate the cyclization reaction and stabilization reaction in the stabilization process through density test and elemental analysis. We also found that the effect of 200 kGy electron beam irradiated fibers with the stabilization time of 75 min was better than that of the original stabilized fibers with 90 min. These results demonstrate that electron beam irradiation can shorten the stabilization time.

Polyoxometalates (POMs) are useful catalysts in both redox and acid catalysis reactions since its catalytic features can be controlled at a molecular level. We investigated POM (POM = H₃PW₁₂O₄₀) on tantalum pentoxide (Ta₂O₅) via hydrolysis of tantalum pentachloride (TaCl₅) in the presence of POM using the sol-gel method for acid catalytic reaction. All obtained amorphous materials have been characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES), Fourier transform infrared (FT-IR) spectra, Raman scattering spectroscopy, ³¹P magic-angle spinning (MAS) NMR, field emission scanning electron microscopy (FESEM), and nitrogen adsorption/desorption analysis, in order to confirm the structure integrity of the Keggin unit in as-prepared composites and investigate the morphology and surface textural property of the composites. Catalytic activity of the catalysts has been evaluated for esterification of acetic acid with ethanol as a model reaction with different catalytic reaction parameters such as POM loading, reaction time, catalyst dose, molar ratio of the reactants, etc. The conversion of ethanol reached 87.4 % and the turnover frequency (TOF) was 2.9×10³.Meanwhile, it is easy to separate and recover POM/Ta₂O₅ from the reaction system.

We prepared and characterized a form-stable composite phase change material (PCM) with higher thermal conductivity. Capric acid(CA)-myristic acid(MA) eutectic as core, poly-methyl methacrylate (PMMA) as supportive matrix and modified graphite (MG) powders serving as the thermal conductance improver were blended by bulk-polymerization method. The composite PCMs with different MG mass fraction (2%, 5%, 7%, 10% and 15%) were characterized by FT-IR, SEM, DSC technique and mechanical tests. Thermal conductivities of the composites were measured by transient hot-wire method. The results indicate that MG powders have been successfully inserted into the CA-MA/PMMA matrix without any chemical reaction with each other. The MG/CA-MA/PMMA composites maintain good thermal storage performance while the thermal conductivity has been enhanced significantly. The composite PCM added with 15 wt% MG powders increases approximately as 195.9% in thermal conductivity. Moreover, the thermal conductivity improvement of the composite PCMs is also verified by the melting-freezing experiment, which is profitable for the heat transfer efficiency in latent heat thermal energy storage system.

Microstructure evolution in neutron irradiated Reactor Pressure Vessel (RPV) steels was experimentally simulated through an improved degradation procedure in this study. The degradation procedure includes austenitizing at 1 150 °C and water quench, deformation 10% and 30% respectively, and then thermal aging at 500 °C for different period of time. The microstructure of the specimens was analyzed in details using transmission electron microscopy (TEM). The micro-hardness test results showed that all the hardness curves of undeformed, 10% pre-deformed and 30% pre-deformed specimens have two micro-hardness peaks with the first peak value corresponding to different thermal aging time of 1 hour, 5 hours and 10 hours, respectively. It was revealed that the hardness curves were influenced by the precipitation of Cu-rich precipitates (CRPs) and carbides, deposition of martensite and work hardening.

The thermodynamics and kinetics of the reaction between Titanium powder and 7075 aluminum alloy were investigated to assess the possibility of preparing TiAl₃/7075 composites by in-situ synthesis method. Results show that Ti and Al melt can form TiAl₃ spontaneously, which is considered as a reinforced phase of the matrix. Measurements such as XRD, SEM, and EDX were performed to characterize the as-synthesized samples, and results confirmed the formation of TiAl₃ in aluminum matrix composites. The reactive kinetics was controlled by three main factors, which are the system temperature, particle size of Ti, and the thickness of external diffusion layer.

The nanocrystalline and amorphous Mg₂Ni-type Mg₂Ni_1−xCo _x (x = 0, 0.1, 0.2, 0.3, 0.4) alloys were synthesized by melt quenching technology. The structures of the as-cast and quenched alloys were characterized by XRD, SEM and HRTEM. The gaseous hydrogen storage kinetics of the alloys was measured using an automatically controlled Sieverts apparatus. The alloy electrodes were charged and discharged with a constant current density in order to investigate the electrochemical hydrogen storage kinetics of the alloys. The results demonstrate that the substitution of Co for Ni results in the formation of secondary phases MgCo₂ and Mg instead of altering the major phase Mg₂Ni. No amorphous phase is detected in the as-quenched Cofree alloy, however, a certain amount of amorphous phase is clearly found in the as-quenched alloys substituted by Co. Furthermore, both the rapid quenching and the Co substitution significantly improve the gaseous and electrochemical hydrogen storage kinetics of the alloys, for which the notable increase of the hydrogen diffusion coefficient (D) along with the limiting current density (I _L) and the obvious decline of the electrochemical impedance generated by both the Co substitution and the rapid quenching are basically responsible.

A top electrophoresis coating was deposited on the surface microarc oxidation (MAO) modified ceramic coating on AZ31 magnesium alloy. Microstructure and corrosion resistance of this composite coating were studied by SEM, electrochemical potentiodynamic polarization, and acid corrosion test. The results showed that the composite coating with a top electrophoresis coating on the surface of ceramic coating exhibited a better corrosion resistance compared with the coating formed by chemical conversion film combined with electrophoresis process. Corrosive ions could permeate into the substrate with corrosion time, and the composite coating was firstly destroyed around the scratch. The formation of composite coating with a higher adhesive force due to the porosity of the ceramic coating contributed to the improved corrosion resistance property.

Chitosan-stavudine (d4T) conjugate with a succinic spacer was synthesized via carbodiimide coupling reaction and structurally characterized. In order to nanosize it for improving its therapeutic properties, the chitosan-5′-O-succinyl-d4T conjugate was crosslinked with sodium tripolyphosphate (TPP) to obtain the chitosan-d4T conjugate nano-prodrug. The morphologies of chitosan-d4T conjugate nanoparticles were observed by transmission electron microscopy (TEM), and their zeta potential, particle size, and polydispersity (size distribution) were measured by the dynamic light scattering (DLS) techniques. In vitro drug release studies at pH 1.1 and pH 7.4 indicate that the crosslinked chitosan-d4T conjugate nano-prodrug can prevent the coupled d4T from leaking out before entering the target viral reservoirs and provide a mild sustained release without the burst release. The results reveal that constructing conjugated chitosan nano-prodrugs may be a promising approach for improving the therapy efficacy of drugs in antiviral treatment.

The reassembly of a half-sequence ionic self-complementarity peptide CH₃CO-Pro-Ser-Phe-Cys-Phe-Lys-Phe-Glu-Pro-NH₂ was reported, which could self-assemble into stable nanofibers and formed hydrogel consisting of >99% water. In this study, the nanofiber scaffold was sonicated by an ultrasonic cell disruptor. The effects of sonication were detected by circular dichroism (CD), atomic force microscopy (AFM), and rheology. AFM image illustrated that the sonicated fragments could quickly reassemble into nanofibers, while the morphology was distinguishable from the original one. CD spectrum revealed that the conversion occurred mainly between regular β-strand structure and distorted β-strand structure. Rheological analyses showed that the storage modulus (G′) of the peptide solution at the 7th day after sonication decreased by nearly 40% compared with the value of the solution before sonication. Finally, a plausible conversion model was proposed to interpret the reassembly process.

We introduced the hydrophilic groups to acrylic bone cement to improve compliance and achieve more interdigitation between the bone and the acrylic bone cement in order to create better substrates for immediate loading. FTIR-ATR, contact angle, and maximum breach torque were employed for measurement. The results reveal that the introduction of hydrophilic functional groups has increased PMMA’s surface hydrophilicity after contact angle test. FTIR-ATR results suggest the hydrophilic groups participate in the polymerization reactions, and maximum breach torque of the hydrophilic acrylic bone cements is near 110 Ncm torque. Those effects make it possible for conventional acrylic bone cement application in immediate loading of dental implant.