CuO-CoO-MnO/SiO₂ nanocomposite aerogels were prepared by using tetraethyl orthosilicate (TEOS) as Si source, and aqueous solution of Cu, Co and Mn acetates as transition metal sources via solgel process and supercritical drying (SCD) technique. The effect of synthesis conditions on gelation was investigated. Moreover, the composition of the CuO-CoO-MnO/SiO₂ nanocomposite aerogels was characterized by electron dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS), and the specific surface area of the nanocomposite aerogels was determined by the Brunauer-Emmett-Teller (BET) method. Diphenyl carbonate (DPC) as the product was analyzed by gas chromatography (GC). The experimental results show that the range of optimal temperature for gelation is 30–45 °C, and the pH is 3.0–4.5. CuO-CoO-MnO/SiO₂ nanocomposite aerogels are porous with a specific surface area of 384.9–700.6 m²/g. Compared to CO₂ SCD, ethanol SCD is even favorable to the formation of aerogel with high specific surface area. The transition metals content in the nanocomposite aerogels can be controlled to be 0.71at%–13.77at%. With CuO-CoO-MnO/SiO₂ nanocomposite aerogels as catalyst carrier, the yield of DPC is in direct proportion to the atomic fraction of transition metals in the nanocomposite aerogels, and it is up to 26.31 mass%, which is much higher than that via other porous carriers.

High purity anatase nano-TiO₂ powders with high photocatalytic activity were prepared by a hydrothermal synthesis method. X-ray diffraction (XRD), field emission transmission electron microscopy (FETEM), ultraviolet-visible (UV-Vis) light absorption spectrum and photoluminescence (PL) spectrum were adopted to characterize the catalyst. Effects of temperature, time and sol concentration of hydrothermal synthesis on particle size and phases were investigated. Photocatalytic activities in the degradation of Rhodamine B Dye were studied. The experimental results indicated that photocatalytic activity of the nano-TiO₂ powers was much higher than that of P25 (Degussa).

Pachyman based nanoparticles loading salicylic acid as model drug (SA-PNPs) were prepared by an inverse microemulsion crosslinking approach using epichlorohydrin (ECH) as crosslinker. The effects of crosslinking reaction time, initial volume ratio of oil to aqueous phase and dosage of crosslinker on the particle size of SA-PNPs were optimized by orthogonal experimental design. SA-PNPs prepared under the optimal conditions had the average size of 230 nm and high encapsulation efficiency of 90%. The in vitro drug release was also investigated and the release data were analyzed using zero order, first order and Higuchi’s kinetics model. According to the determined coefficients, release data fitted to Higuchi’s model, which suggested that the release of SA from SA-PNPs in phosphate buffer (pH 7.4) was diffusion controlled release. The experimental results indicated that pachyman possesses a promising potential to be applied as nanocarriers for controlled drug release.

Monodisperse ZrO₂ nanoparticles capped by trioctylphosphine oxide (TOPO) were prepared in non-aqueous solvent using in-situ synthesis method. Transmission electron microscopy(TEM), X-ray diffraction(XRD), X-ray photoelectron spectrometer(XPS), Fourier transformation infrared spectroscopy (FTIR), and thermogravimetric analysis(TGA) were adopted to characterize and investigate the size, structure, composition, and the binding manners between organic capping agent TOPO and inorganic ZrO₂ nanocores of the as-prepared nanoparticles. In addition, the nanoparticles were also studied to determine their solubility and relative stability. The experimental results show that the prepared nanoparticles contain about 25% organic capping shell TOPO, 75% inorganic ZrO₂ nanocores, and can be easily dissolved and be stably disersed in nonpolar organic solvents.

Attapulgite fibers were modified by polyurethane, forming polyurethane grafted attapulgite (AT-PU), which was confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Nylon 6/AT-PU nanocomposites of different modified attapulgite loadings were prepared by melt blending in a twin screw extruder. Scanning electron microscopy (SEM) observation on the fracture surfaces of the nanocomposites showed not only a uniform dispersion of AT-PU but also a strong interfacial adhesion with the matrix. Differential scanning calorimeter (DSC) and Thermogravimetric analyzer (TGA) were used to illustrate the influence of AT-PU particles on the thermal properties of the nylon 6/AT-PU nanocomposites. The results indicated that the addition of attapulgite probably induced the heterogeneous nucleation and was favorable for the formation of γ -crystalline form, and that the higher thermal stability was obtained for the composites.

The morphology and the formation of Y₂BaCuO₅ phase in powder melting processed YBa₂Cu₃O_7−x superconductors were investigated. The experimental results show the heat treatment can not change the shape of Y₂BaCuO₅ particles in powder melting processed samples. The formation of round Y₂BaCuO₅ phase is due to relative content of each constitution of precursor powders in powder melting process. For powder melting process, the excessive liquid phase is eliminated, which restrains the preferred growth of Y₂BaCuO₅ particles.

LiFePO₄ nanorods were facilely synthesized under hydrothermal condition. The crystalline structure and particle morphology of LiFePO₄ powders were characterized by X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). The electrochemical properties of LiFePO₄/Li cells were investigated by galvanostatic test and cyclic voltammetry (CV). The XRD result demonstrated LiFePO₄ powder had an orthorhombic structure with a space group of Pnma. The synthesized LiFePO₄ nanorods exhibited a first discharge capacity of 155 mAh·g⁻¹ (91% of theorectical capacity) close to the theorectical capacity of LiFePO₄ (170 mAh · g⁻¹) at 0.1 C.

A kind of slow release drug-loaded microspheres were prepared with gelatin, chitosan and montmorillonite(MMT) by an emulsification/chemical cross-linking method using glutaraldehyde as crosslinking agent and acyclovir as model drug. The microspheres were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM), respectively. The morphology, drug content, encapsulation efficiency and drug-release behavior were investigated with different MMT contents. The experimental results indicated that intercalated microspheres could be prepared, the morphology of microspheres was markedly affected by MMT. The glomeration performance of uncross-linked microspheres was improved because of the physical cross-linking of MMT. Drug content and encapsulation efficiency were decreased when increased the content of MMT, but burst release and the drug release were signifi cantly decreased with the addition of MMT. Effective physical cross-linking could be formed when added MMT, and MMT could reduce the content of toxic chemical cross-linking agents.

The effect of culture in KLD-12 self-assembling peptide nanofiber scaffold containing TGF-β3 gene on differentiation of precartilaginous stem cells (PSCs) into chondrocytes was studied. KLD-12 was synthesized by solid-state method. After TGF-β3 plasmid was loaded into KLD-12 self-assembling peptide nanofiber scaffold, DNA release ability was investigated. PSCs and hTGF-β3 gene were loaded into KLD-12 3-D scaffold, and MTT assay was performed to investigate the cell proliferation, and ELASA assay was used to investigate the expression of TGF-β3. Specific cartilage matrix was examined by quantitative real-time PCR, immunohistochemistry and Alcian Blue staining. Compared with control group, DNA synthesis level of PSCs reached the peak within 3 days when PSCs were cultured in self-assembling peptide nanofiber scaffold loading TGF-β3 plasmid, and maintained this high level within 2 weeks. MTT results showed that the proliferation ability of experimental group was statistically higher than that in control group (P<0.05). Quantitative realtime PCR suggested that the percentage of TGF-β3 positive PSCs in experimental group was higher than that in control group (P<0.01). ELISA assay showed that the TGF-β3 protein level increased in supernatant of experimental group’s PSCs, reached the peak after 72 h and then declined a little to the plateau phase. Compared with the control group, the specific gene of chondrocyte typical extracellular matrix significantly up-regulated (P<0.01). The results showed that PSCs differentiated into chondrocytes in self-assembling peptide nanofiber scaffold loading TGF-β3 plasmid, which provided a fresh approach to cartilage tissue engineering.

The electrochemical behaviors of 2205 duplex stainless steel in NaCl solution with different temperatures and concentrations were studied by gravimetric tests, potentiodynamic polarization, electrochemical impedance spectroscopy and scanning electron microscopy. The experinental results show that temperature and chloride concentration have a great influence on the pitting resistance of 2205 duplex stainless steels. They not only effect the corrosion rate of pitting, but also change the shape of the pits. When NaCl solution was in low concentration and temperature below the critical pitting temperature, pits were very small and scattered with hemisphere-like shape. On the contrary, the pits of 2205 duplex stainless steel were large and sometimes had a lacy cover when the NaCl concentration was higher and the temperature was 70°C.

The effect of pre-corrosion on fatigue behavior of high strength steel 38CrMoAl was investigated with a fatigue test method using the accelerated pre-corrosion specimen in the neutral salt spray environment. The methods of weight-loss and energy dispersive spectrum (EDS) were adopted. The corrosion weight-loss rate was fitted with the test time using power law, and the relationship between the corrosion weightloss rate and the time was formulated. Moreover, the fatigue behaviors of the steel for different pre-corrosion time were investigated by the axis-direction tensile fatigue test. The fatigue life distribution characteristics of the pre-corrosion specimens were studied using the statistical probability methods, and the mathematical expectations and the standard tolerances of the material fatigue lives after different pre-corrosion time were obtained. It was found that the crack initiation of the high strength steel was accelerated by the preferential corrosion at the local plastic deform areas. The fatigue life obeys the lognormal distribution perfectly. Furthermore, within the common time range of the engineering, the standard tolerances of the logarithm of the fatigue life were independent of the pre-corrosion time.

Microstructure evolution of AZ31 Mg alloy during change-channel angular extrusion (CCAE) was investigated. The grains of AZ31 Mg alloy were refined significantly from 500 μm to 15 μm after CCAE deformed at 523 K. Dislocations were induced at the initial stage of extrusion and they rearranged themselves to form dislocation boundaries and sub-grain boundaries during deformation. When the specimen through the horizontal change channel with the strain increased, the sub-boundaries evolved to high angle grain boundaries (HAGB). The process of grain refinement can be described as continuous dynamic recovery and recrystallization (CDRR).

Molecular dynamics (MD) simulations were used to study a sliding friction process between DLC films on various boundary conditions. The experimental results revealed that, in the absence of a lubricant, a transfer film between the DLC films was formed. In contrast, when the oil or water lubricants were added to lubricate between the DLC films, a boundary lubrication layer was found. The friction forces on the water and oil lubrication were almost the same, but the friction force in the absence of a lubricant was larger than those on the water and oil lubrication. The conclusions were in good agreement with the experiments.

Using organo-tin Sn(OC₄H₉)₄ as precursor, sodium dodecyl sulfonate (SDS) and SDS-gelatin (SDS-G) complex as template, two tin dioxide colloidal particles were prepared by a self-assembly method. Both SnO₂ products were respectively labelled SnO₂-B particles with SDS and SnO₂-C particles with SDS-G, which are applied in fabricating SnO₂ gas sensors corresponding to SnO₂-B′ and SnO₂-C′ sensors. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetry and different thermal analysis (TG/DTA) were used for characterizations. The experimental results show that SnO₂-B colloidal particles are composed of mesoporous piece-like particles, while SnO₂-C particles mainly consist of spherical particles. Gas sensing measurements show that SnO₂-B′ sensor performs the best sensing response to all target gases, including H₂, C₂H₅OH and liquid petroleum gas (LPG). In particular, the sensing response of SnO₂-B′ sensor is achieved at 32 in H₂ atmosphere at the concentration of 1000×10⁻⁶ M. The gas sensing mechanism was purposely discussed from the electron transfer process and the microstructures of the as-prepared SnO₂ products. It is found that serious agglomerations in SnO₂-B′ particles facilitate the high gas sensing performance of SnO₂-B′ sensor, while mesoporous structures in SnO₂-C′ particles decrease the gas sensing response of SnO₂-C′ sensor.

Influences of addition of CaO, CoO and V₂O₅ on the microstructure and magnetic properties of (Mg_0.476Mn_0.448Zn_0.007)(Fe_1.997Ti_0.002)O₄ ferrites were investigated. The powders of (Mg_0.476Mn_0.448Zn_0.007) (Fe_1.997Ti_0.002)O₄ composition were prepared by using a conventional ceramic powder processing technique. The experimental results showed that the average grain size of the sintered ferrites codoped with 0.03wt% CaO, 0.04wt% CoO and 0.06wt% V₂O₅ was about 15 μm; the saturation magnetization of ferrites was 68.78 emu/g. The addition of V₂O₅ in the ferrites can not only increase value of the saturation magnetization, but also decrease the average grain size of (Mg_0.476Mn_0.448Zn_0.007)(Fe_1.997Ti_0.002)O₄ ferrites. Simultaneous incorporation of CoO, CaO and V₂O₅ dopants into (Mg_0.476Mn_0.448Zn_0.007)(Fe_1.997Ti_0.002)O₄ ferrites can not only improve the saturation magnetization of the materials, but also inhibit abnormal grain growth.

Aluminum foam sandwich was prepared by rolling-bonding/powder metallurgical foaming technology, and the effects of rolling on bond strength of face sheet/powders and powder density were studied. Moreover, the foaming agent, TiH₂, was heat treated and a certain amount of Mg was added into powder in an attempt to understand how the stability and uniformity of foam was improved. The experimental results show that the foaming precursors with ideal quality were obtained by rolling-bonding process. When rolling reduction is 67%, the consistency of powders reach to 99.87%. Throughout consideration of the bonding of face sheet/core layer powders and deformation characteristic of powders, the optimum rolling reduction is 60%–70%. Cracks and drainage during foaming were inhibited by heat treatment of foaming agent TiH₂ and the addition of a certain amount of Mg. The optimum heat treatment way of TiH₂ is that heat preserving 1 hour at 450 °C; the amount of adding Mg is 1wt%.

A novel antibacterial material (L-PET) was prepared by immobilizing ɛ-polylysine on polyethylene terephthalate (PET) nonwoven fabrics. Surface modifications of the fabric were performed by using a chemical modification procedure where carboxyl groups were prepared on the PET surface, a coupling agent was grafted, and the ɛ-polylysine was immobilized. Scanning electron microscopy (SEM) was used to analyze the surface morphology of the fabrics, while the toluidine blue method and X-ray photoelectron spectroscopy (XPS) were used to evaluate the grafting densities. The antibacterial activities of the L-PET were investigated by using the shaking-flask method. The electron micrographs showed that the surface of the blank PET and the modified fabrics did not change. The results of XPS analysis confirmed that ɛ-polylysine was successfully grafted onto the surface of PET. The results of the antibacterial experiments showed that L-PET fabrics had excellent antibacterial activity against Escherichia coli and Staphylococcus aureus, and that L-PET fabrics were stable in storage for at least two years.

In order to get a homogenous mixture and compact of TiB₂-Al₂O₃, hybridization as a surface modification method was used to prepare nano-scale Al₂O₃ coated TiB₂ particles. PE-wax particles were first coated onto TiB₂ particles by hybridization, and then the nano-scale Al₂O₃ particles were coated onto the surface of TiB₂ coated by PE-wax particles again. SEM, TEM and EDS were used to characterize the microstructure of as-received core/shell particles and its compacts. The experimental results show that a particle-scale homogenous dispersion of TiB₂ and Al₂O₃ can be formed not only in mixed powder but also in dewaxed compacts. The compacts then were sintered by gas-pressing sintering (GPS). Finial products show improved mechanic properties comparing with reference samples fabricated by normal ways.

Absorption/desorption properties of some humidity controlling materials which contain gypsum as basic cement materials and activated Sepiolite powder as humidity controlling media were tested. The kinetics curve of moisture adsorption/desorption were drawn and humidity controlling performance in nature environment was verified. The experimental results show that moisture absorption/desorption rates are increased, and the speed is also accelerated. These materials, which can adjust environmental humidity effectively, are new ones with good humidity controlling performance.

1 064 nm, 532 nm frequency-doubled antireflection (AR) coatings with buffer layer of SiO₂ between the coating and the substrate were fabricated by the electron beam evaporation technology on the substrate of lithium triborate (LiB₃O₅ or LBO) crystals. The residual reflectance of the sample is 0.07% and 0.11% at 1 064 nm and 532 nm, respectively. The adhesion and the laser-induced damage threshold (LIDT) of the sample are greater than 200 mN and 18.6 J/cm². The strengthening mechanism of adhesion and LIDT of the buffer layer of SiO₂ were discussed by considering full plastic indentation and shear theory, and spallation of a plated film induced by thermal shock stress, respectively.

The influence of various alumina additions on the optical property of zirconia/alumina composite ceramics was investigated. The relative sintered densities, transmittances, color and the microstructure of the composite ceramics were studied. The experimental results showed that the relative sintered densities and transmittances decreased with alumina addition. The lightness increased obviously but the chroma change was small. Pure zirconia nanopowders sintered densely could obtain the relatively high transmittance, while the transmittance and the lightness of slight addition changed significantly. The zirconia/alumina composite ceramics with alumina addition less than 7.5wt% could achieve the relatively stable and reliable optical properties.

Effects of Al₂O₃ and Ni as the additives on the sinterability, microstructure and mechanical properties were systematic studied. The experimental results show that only a relative density about 96.2% of hot-pressing TiB₂-30%Al₂O₃ can be attained due to the plate-like TiB₂ particle and its random orientation and excessive Al₂O₃ grain growth. When sintering temperature is higher than 1 700 °C, TiB₂ grain growth can be found, which obvious improves flexural strength of TiB₂ matrix but decreases toughness. It seems that mechanical properties of TiB₂-Al₂O₃ composites are mainly depended on relative density besides grain growth. otherwise, they will be determined by relative density and TiB₂ matrix strength together. Anyway, Al₂O₃ addition can weaken the grain boundary and thus improve the toughness of the materials. A flexural strength of 529 MPa, Vickers hardness of 24.8 GPa and indentation toughness of 4.56 MPa·m^1/2 can be achieved inTiB₂-30vol% Al₂O₃.

The ZnO powder with hexagonal-pyramids structure was prepared by the low-temperature combustion process. Ammonium acetate was used as the fuels, whereas zinc nitrate acted as the oxidant. The effect of different ration between fuel and oxidant on the morphology and photoluminescence (PL) characteristic was studied. The formation of hexagonal-pyramids structure was discussed. The optimum preparing parameter for fine morphology is that the ratio of zinc nitrate and ammonium acetate is 1:5, and ignition temperature is 500 °C. The PL measurement indicates all samples have the strong blue and yellow emission peak. The changes of surface energy of the polar surfaces result in the formation of micro-pyramids structure.

Two kinds of new room temperature ionic liquids (RTILs), 1-allyl-3-methylimidazolium chloride (AMIMCl) and 1-butyl-3-methylimidazolium chloride (BMIMCl), were synthesized and used for the dissolution of konjac glucomannan (KGM). The experimental results showed that the solubility of KGM in AMIMCl was better than that in BMIMCl. Regenerated KGM were obtained by adding anhydrous alcohol to the KGM / ionic liquids solutions. Solubility, molecular weight, structure, and thermal property of the regenerated KGM were investigated by polarized optical microscopy (POM), viscosimetry, infrared spectroscopy (IR), X-ray diffraction technique (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). It was demonstrated that the viscosity-averaged molecular weight of the KGM samples decreased after regeneration because of the molecular degradation of KGM. Results from IR and XRD indicated that the chemical structure and the crystalline form of regenerated KGM were not changed. Results from TG and DSC showed that the thermal stability of the regenerated KGM samples only slightly decreased. These results suggest that AMIMCl and BMIMCl are direct and effective solvents for KGM.

The precursor with TiC_0.7N_0.3@WO₃-MO₃ microspheres were prepared by a novel method from the WO₃-MoO₃ sol dipping. Subsequently, TiC_0.7N_0.3@WC-MoC₂ core-shell structural microspheres were successfully obtained by carburizing the precursor at 900 °C in a flowing mixture of CH4 (20 ml · min⁻¹) and H₂ (200 ml · min⁻¹) for 2 h. Then TiC_0.7N_0.3@WC-MoC₂-15Co cermets were prepared utilizing the core-shell powders by spark plasma sintering (SPS). Powders of the precursors with TiC_0.7N_0.3@WO₃-MO₃ microspheres, TiC_0.7N_0.3@WC-MoC₂ microspheres and TiC_0.7N_0.3@WC-MoC₂-15Co cermets were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The obtained TiC_0.7N_0.3@WC-MoC₂ microspheres have a dense WC-MoC₂ coatings shell. The thickness of the shell could be easily controlled by adjusting the number of sol dipping cycles. It was found that the TiC0.7N_0.3@WC-MoC₂ microspheres were more beneficial to fabricate the “core-rim” structures by SPS.

In order to produce the hear-resistant inner layer of hot-forging die, plasma spraying and plasma re-melting and plasma spray welding were adopted. Substrate material was W6Mo5Cr4V2, including 10%, 20%, 30% SiC ceramic powder used as coating material to obtain different Ni-based SiC alloys coating. Micro-structure and micro-hardness analysis of the coating layer were followed, as well as thermophysical properties for the coating layer were measured. The experimental results show that the coating prepared with 70% Ni60, 30% SiC powder has best properties with plasma spray welding, in which the micro-hardness can achieve 1100 HV, meanwhile can improve the thermal property of hot-forging die dramatically.

The formation process of calcium suphoaluminate(C₄A₃S) was investigated by the X-ray diffraction technique and then the thermodynamics was analyzed, finally the kinetics of which was studied by SC-132. XRD results show that the formation of C₄A₃S is accomplished in three different kinds of ways: one is by solid reaction of Ca (OH)₂/CaO, Al₂O₃ and CaSO₄, other two ways are through such interstitial products as CaO·Al₂O₃ and CaO·₂Al₂O₃. The formation thermodynamics shows that C₄A₃S begins to form at 900 °C–1 000 °C and increases as temperature rising; the quantity of reaches the highest at 1 300 °C–1 350 °C and then falls at >1350°C. Kinetics study shows that the formation rate of C₄A₃S can be described as first-order kinetics at high temperature, and it belongs to the random nucleation growth mechanism. The apparent activation energy is 456.37 kJ·mol⁻¹ and pre-exponential factor is 1.545×10¹².

Waste solid propylene oxide sludge (POS) and fly ash were used as main raw material to prepare propylene oxide sludge aggregate (POSA) under the condition of autoclaved (180 °C, 1.0 MPa) curing. Three different test methods namely cylinder compressive strength (CCS), individual aggregate compressive strength (IACS) and strength contribution rate (SCR) proposed were used to characterize the mechanical properties of the autoclaved POSA. POS shell-aggregate with SCR of 94% were prepared under the hydrothermal synthesis and autoclaved curing. The experimental results indicate that CCS and IACS have good consistency in characterizing mechanical properties of POSA. It is suggested that SCR not only can characterize the strength of POSA core, but also can reflect the effect of shell on the performance of POSA. By means of least square method, relationships between CCS and IACS, CCS and SCR, IACS and SCR were deduced.

The behaviour of square concrete-filled steel tube columns under concentrical loading was studied. More than one hundred specimens were tested to investigate the effects of thickness of steel tube on the load carrying capacity of the concrete-filled tubular columns (CFTs). The effect of the grade of concrete and content of expansive agent were also investigated. The effect of these parameters on the confinement of the concrete core was studied as well. From the experimental study it was found that for both CFTs with different strength grade concrete core, the ultimate load carrying capacity increases with the increase in percentage of expansive agent up to 20% but it again decreases at 25% of expansive agent content. It was also shown that the failure mode of CFTs depends on the strength grade of concrete core.

The inhibition and its mechanism of sodium tripolyphosphate (STP) composited with super plasticizers (SPs) on hydration of α-calcium sulfate hemihydrate were studied by setting time, strength, hydration heat, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electronic probe micro analysis (EPMA), scanning electron microscopy (SEM) and differential scanning calorimeter (DSC) measurements. The experimental results show that compared with STP addition, compositing STP with polycarboxylate (PC) plasticizer, the final setting time is prolonged from 0.5h to 2hs. While formulating STP with naphthalene-based plasticizer (NAP) or sulfonate melamine formaldehyde plasticizer (SMF), the final setting time is reduced to quarter of an hour. Similar changes can also be found in the rate of exothermic hydration and hydration degree. Formulating STP with suitable addition of PC can enhance the strength, while compositing STP and NAP or SMF weakens the strength. Besides, adding STP or STP and SMF, obvious movement (more than 1ev) of binding energy of Ca2p1/2 and Ca2p3/2 is detected. Compared with STP addition, content of the characteristic element (P) of STP is cut down form 1.1% to 0.49% by compositing STP with SMF. Furthermore, as hydration age increases, hydration inhibition in the presence of admixtures weakens and even disappears within 56 h.

The paste was prepared by mixing MgO, microsilica and H₂O in the presence of water reducer at different reaction ratios and temperatures, and characterized by XRD, DTA, TGA, IR, and solid-state 29Si NMR. The experimental results showed that, besides Mg(OH)₂, magnesium silicate hydrate (M-S-H) was formed at a low temperature such as 25 and 50 °C. At a high temperature of 100 °C, Mg(OH)₂ can be further transformed into M-S-H completely, for instance, within ca. 1 month in an excess of microsilica. The average composition and structure of M-S-H was mainly related to the reaction mixture and curing temperature and was discussed in detail.

In order to explore the serviceability and reinforcement of CaCO₃ whisker in portland cement matrix, the durability of CaCO₃ whisker and effect of low whisker content(0%–4.0%) on the working performance and mechanical properties of portland cement were investigated. The experimental results show that CaCO₃ whiskers have a good stability and serviceability in cement, and should not significantly alter the rheological properties of the cement paste. The flexural and compressive strength of portland cement reinforced by CaCO₃ whiskers was increased by 33.3% and 12.83%, respectively.

A self-compacting ultra-high toughness cementitious composite (UHTCC) reinforced by discontinuous short polyvinyl alcohol (PVA) fibers, which exhibits self-compacting performance in the fresh state and strain-hardening and multiple cracking behavior in the hardened state, was developed through controlling flow properties of fresh mortar matrix at constant ingredients concentrations determined by micromechanical design and ensuring uniform fibers dispersion. The superplasticizer was utilized to adjust its flow properties in the fresh state. A series of flow tests, including deformability test, flow rate test, and self-placing test, were conducted to characterize and quantify the fluidity performance of fresh mortar matrix and self-compactability of fresh UHTCC. It is revealed that the utilization of superplasticizer is efficient in producing the fresh mortar matrix with desirable fluidity and the resulting self-compacting UHTCC. In addition, results of four point bending tests on the developed self-compacting UHTCC confirm the insensitivity of mechanical performance of self-compacting UHTCC to the presence of external vibrations as well as the flexural characteristics of deformation hardening and multiple cracking.

Uniaxial compression tests were conducted to characterize the main compressive performance of ultra high toughness cementitious composite (UHTCC) in terms of strength and toughness and to obtain its stress-strain relationships. The compressive strength investigated ranges from 30 MPa to 60 MPa. Complete stress-strain curves were directly obtained, and the strength indexes, including uniaxial compressive strength, compressive strain at peak stress, elastic modulus and Poisson’s ratio, were calculated. The comparisons between UHTCC and matrix were also carried out to understand the fiber effect on the compressive strength indexes. Three dimensionless toughness indexes were calculated, which either represent its relative improvement in energy absorption capacity because of fiber addition or provide an indication of its behavior relative to a rigid-plastic material. Moreover, two new toughness indexes, which were named as post-crack deformation energy and equivalent compressive strength, were proposed and calculated with the aim at linking up the compressive toughness of UHTCC with the existing design concept of concrete. The failure mode was also given. The study production provides material characteristics for the practical engineering application of UHTCC.

The samples of the C-S-H series were synthesized by hydrothermal reaction of fumed silica, CaO and deionized water at initial C/S ratios between 1.0–1.7. Phase composition and structural and morphology characteristics of C-S-H samples were analyzed by XRD, IR and SEM. The experimental results showed that the d-spacing of (002), (110) and (020) decreased, the d-spacing of (200) increased, and the d-spacing of (310) varied randomly, the polymerization of silica tetrahedra of C-S-H decreased, and morphology of C-S-H samples varied from sheet shapes to long reticular fibers as C/S ratio increased.

An experimental program was carried out to investigate whether EVA (ethylene vinyl acetate copolymer) heat-melt adhesive can potentially act as a self-healing agent in cement-based material. The effects of incorporation of EVA and heating on the properties of mortar were studied. Self-healing capacity of EVA specimens was also verified. The experimental results show that the addition of EVA would not greatly affect original characteristics of the matrix when EVA content was less than 5%; the interface between EVA and cement matrix was well improved after heating, which allows a significant improvement in flexural strength and toughness of specimen; pre-damaged specimens in various degrees (30%, 50% and 70%) were effectively repaired by EVA and the repair efficiency all exceeded 100%.

The expansive behaviors of the expensive concrete under different restraining conditions were systemically studied. The experimental results indicate that expansive deformation obviously increases before 10 days and tends to be constant after 25 days regardless of the restraining conditions. The mixture ratio of expansive cement and restraining conditions are the main factors affecting expansive deformation. Self-stress can be obtained when the expansive deformation is restrained. The higher self-stress could be obtained when the expensive concrete is restrained by steel tube. For specimens under steel tube restraining, the wall thickness and the length of the steel tube have important influence on self-stress. Both the radial self-stress and axial self-stress in concrete core increase when wall thickness or length of the steel tube increases.

The effect of combination of steel fiber and MgO-type expansive agent (MEA) on strength, air-permeability and porosity of concrete was investigated. The porosity and air-permeability of concrete were determined by method of evaporated water and Torrent permeability tester, respectively. Pore structures of mortars in concrete were analyzed using mercury intrusion porosimetry (MIP). Interfacial structures between steel fibers and matrix were examined by use of optical microscope. The experimental results show that improvement of pore structures of mortar and fiber-matrix interfacial structure in concrete by combination of steel fiber and MEA may remarkably increase properties of concrete. In comparison with plain concrete, compressive strength and splitting tensile strength of steel fiber reinforced expansive concrete increased by 15.3% and 38.1%, permeability coefficient K _t, penetration depth L and porosity of concrete decreased by 41.1%, 21.3% and 13.1% at 28 days, respectively.

A very simple model for predicting thermal conductivity based on its definiensis was presented. The thermal conductivity obtained using the model provided a good coincidence to the investigations performed by other authors. The heat transfer coefficient was determined by inverse analysis using the temperature measurements. From experimental results, it is noted that heat transfer coefficient increases with the increase of wind velocity and relative humidity, a prediction equation on heat transfer coefficient about wind velocity and relative humidity is given.

New Mg₂Si based alloy were prepared by mechanical alloying. Sintering temperature was from 825 to 865K, which indicated that few Mg₂Si were produced at lower temperature while MgO were produced at higher temperature. Microstructure image showed that at sintering temperature of 855K, Mg₂Si were mostly synthesized with the reaction of purity magnesia powder and silicon powder. Hardness and wear tests proved that the new synthetic silicon magnesium alloy had higher hardness and good wear resistance. Under the same testing conditions, it is found that the hardness of the new material is 420.50, and pure magnesium is only 41.65.In the same experiments it is also found that under the same pressure, pure magnesium alloys than silicon wearing capacity of pure magnesium is 2 times as high that of Mg₂Si based alloy. It shows that Mg₂Si based alloy is the ideal material for the wear parts of car engine cylinder liner because of its small density, stable dimension, high hardness and wear-resisting.

Based on the car front-wheel-hub forging forming process of numerical simulation, the temperature gradient expression of forging model cavity near the surface layer was got ten, which illustrates that the forging temperature gradient is related to forging die materials thermal conductivity, specific heat and impact speed, and the correlation coefficient is 0.97. Under the different thermal conductivity, heat capacity and forging speed, the temperature gradient was compared with each other. The paper obtained the relevant laws, which illustrates the temperature gradient relates to these three parameters in a sequence of thermal conductivity > impact speed> specific heat capacity. To reduce thermal stress in the near-surface layer of hot forging cavity, the material with greater thermal conductivity coefficient and specific heat capacity should be used.