Normal spinel LiMn₂O₄ was synthesized by sol-gel method using lithium nitrate, manganese nitrate, citric acid and ethylene glycol as raw materials. LiMn₂O₄ was characterized by XRD, TG-DTA, IR, SEM and AAS. The optimum conditions for the synthesis were explored. Citric acid and ethylene glycol were mixed with molar ratio of 0.25, and the mixture was esterified at 140°C for 4 hours. Then lithium nitrate and manganese nitrate were added with molar ratio of 0.6. In the system, the total molar of cations was equal to that of citric acid. At last, reflux the system at 105°C for 2 hours. Dried gel was fired at 600°C for 8 hours. Particle diameters of raw product were about 100 nm mainly. Further research shows that lithium ion of LiMn₂O₄ is easy to be extracted, and normal spinel λ-MnO₂ can be obtained after lithium ion extraction.

BN ceramic is an advanced engineering ceramics with excellent thermal shock resistance, good workability and excellent dielectricity. TiB₂ ceramic has excellent electric conductivity, high melting points, and corrosion resistance to molten metal. Therefore, the composite consisting of BN and TiB₂ ceramics is expected to have a combination of above-mentioned properties, thereby can be used as self- heating crucible. In this paper, hot pressing technology was used to fabricate the high performance BN-TiB₂ composite materials. microstructure and electric conducting mechanism were studied, and the relationship between the microstructure and physical property was discussed. The results show that the microstructure of composites has a great influence on the physical property of composites. The BN-TiB₂ composites with excellent mechanical strength and stable resistivity can be obtained by optimizing the processing parameter and controlling the microstructure of composites.

Effects of Ba filling fraction on the thermoelectric properties of p-type filled skutterudite compounds Ba_yFe_1.6Co_2.4Sb₁₂ (y=0−0.63) were investigated. Ba_yFe_1.6Co_2.4Sb₁₂ showed p-type conduction. The hall coefficient (R_h) and seebeck coefficient (α) increased with increasing Ba filling fraction. But hole concentration (p) and electrical conductivity (σ) decreased. While Ba filling fraction was about 0.4, the lattice thermal conductivity (k_L) reached the minimum value. The results show that effect of Ba rattling on phonon scattering is the strongest as Sb-icosahedron partial voids are filled by Ba. A maximum dimensionless thermoelectric figure of merit (ZT) value of 0.7 was obtained for Ba_0.38Fe_1.6Co_2.4Sb₁₂ at 750 K.

An Al-50wt% TiC composite was directly synthesized by self-propagating high-temperature synthesis (SHS) technology, and then was used as a grain refining master alloy for commercially pure aluminum. the microstructure and grain refining performance of the synthesized master alloy were emphatically investigated. The SHS master alloy only contained submicron TiC particles except for Al matrix. Moreover, TiC particles were relatively free of agglomeration. Grain refining tests show that adding only 0.1 wt% of the master alloys to the aluminum melt could transform the structure of the solidified samples from coarse columnar grains to fine equiaxed grains (average grain size 120 μm), and that this grain refining effectiveness could be maintained for almost 1. 5h at 1003 K. Therefore, it is concluded that the SHS master alloy is an effective grain refiner for aluminum and its alloys, and that it is highly resistant to the grain refining fading encountered with most grain refiners.

The manner by which the particles settle in the laminar flow region is first described and the characteristics of co-sedimentation of two-species particles are summarized. The subsequent introduction is focused on the fabrication process of continuously graded composites using co-sedimentation technique. Finally, the authors point out the key problem that should be solved immediately, based on their current work.

Ag−TiO₂ thin films were prepared on glasses. The morphology and structure of Ag−TiO₂ films were investigated by XRD, SEM and FT-IR. The photocatalytic and hydrophilic properties of Ag−TiO₂ thin films were also evaluated by examining photocatalytic degradation dichlorophos under sunlight illumination and the change of contact angle respectively. The research results show that the Ag−TiO₂ thin film is mainly composed of 20–100 nm Ag and TiO₂ particles. The Ag−TiO₂ thin films possess a super-hydrophilic ability and higher photocatalytic activity than that of pure TiO₂ thin film.

To develop a new generation of absorbable fracture fixation devices with enhanced biocompatibility, the biodegradation mechanism and its influence on the cellular response at the tissue/implant interface of hydroxyapatite/poly-DL-lactide (HA/PDLIA) composites were investigated in vitro and in vivo. HA/PDLIA rods were immersed in phosphate-buffered saline, or implanted in muscle and bony tissue for 52 weeks. Scanning electron microscopic and histological studies were done. The degradation rate was the slowest in vitro, slower in muscle tissue and fast in bone. In vitro, the composites degraded heterogeneously and a hollow structure was formed. In bone, the limited clearing capacity leads to the accumulation of oligomeric debris, which contribute totally to the autocatalytic effect. So, the fastest degradation and intense tissue response were seen. In muscle tissue, oligomeric debris migrated into vicinal fibers over a long distance from the original implant cavity and the tissue reactions were, however, quite moderate. For the same size organic/inorganic composite, the environment where it was placed is the major factor in determining its biodegradation process and cellular reaction. In living tissue, factors such as cells, enzymes and mechanical stress have an obvious influence on the biodegradation and biological process at the tissue/implant interface. The biocompatibility of the HA/PDLIA composites is enhanced with the incorporating of the resorbable HA microparticles.

Tissue engineering has confronted many difficulties mainly as follows: 1) How to modulate the adherence, proliferation, and oriented differentiation of seed cells, especially that of stemcells. 2) Massive preparation and sustained controllable delivery of tissue inducing factors or plasmid DNA, such as growth factors, angiogenesis stimulators, and so on. 3) Development of “intelligent biomimetic materials” as extracellular matrix with a good superficial and structural compatibility as well as biological activity to stimulate predictable, controllable and desirable responses under defined conditions. Molecular biology is currently one of the most exciting fields of research across life sciences, and the advances in it also bring a bright future for tissue engineering to overcome these difficulties. In recent years, tissue engineering benefits a lot from molecular biology. Only a comprehensive understanding of the involved ingredients of tissue engineering (cells tissue inducing factors, genes, biomaterials) and the subtle relationships between them at molecular level can lead to a successful manipulation of reparative processes and a better biological substitute. Molecular tissue engineering, the offspring of the tissue engineering and molecular biology, has gained an increasing importance in recent years. It offers the promise of not simply replacing tissue, but improving the restoration. The studies presented in this article put forward this new concept for the first time and provide an insight into the basic principles, status and challenges of this emerging technology.

α-tricalcium phosphate (α-TCP)/tetracalcium phosphate (TTCP) composite bone cement had good hydration characteristic. In our system, α-TCP/TTCP powder mixture was mixed with water at a powder/liquid (P/L) ratio of 1.50g·mL⁻¹. The setting time could be adjusted, the maximum compressive strength was 45.36MPa, and the hydration product was hydroxyapatite (HAP). In vitro biological simulated experiments indicate that α-TCP/TTCP bone cement has α certain dissolubility. The hardened product is mainly HAP after soaking in simulated body fluid (SBF) for 10 weeks. The results of in vitro test and animal experiments and SEM analyses show that no local or general toxicity response, no muscle stimulation, no haemolysis, no cruor, no inflammatory reaction and no exclusion response are caused by α-TCP/TTCP cement, which can be contributed to bone tissue spreading and impinging. α-TCP/TTCP cement hydrated and hardened continually in vivo. The materials fused with host bone together with implanting time prolonging. Therefore, it is believed that α-TCP/TTCP composite bone cement has a high biocompatibility and bioactivity, a certain biodegradation and good osteogenesis as well.

This paper discussed the preparing process of hydroxyapatite fibers which were widely used as reinformcement for biomedical materials by homogeneous precipitation method. The needle-like hydroxyapatite crystals were synthesized in an aqueous system. They were transferred from precursors-dicalcium phosphate anhydrate and octacalcium phosphate crystals. The reaction conditions were well controlled in order to obtain crystals in given morphology. The products were characterized by X-ray powder diffractometry (XRD), scanning electron microscopy (SEM) and infrared spectroscopy(IR). They were verified to be hydroxyapatite crystals with needle-like in shape.

The effect of the melt superheating temperature on the as-cast microstructure of a cast nickel-base superalloy M963 has been investigated. The results show that the as-cast microstructure of the alloy consists of γ solid solution matrix, γ′ precipitate in cubic shape, (γ+γ′) eutectic and MC carbide, and the morphology of MC carbide in the microstructure can be varied from coarse scriplike, fine scriptlike to fine cubelike or discontinuous particles by increasing the melt superheating temperature. The mechanism of melt superheating is discussed by means of differential thermal analysis (DTA) technique.

The bonding of steel plate to Al-7 graphite slurry was studied for the first time. The relationship model about preheat temperature of steel plate, solid fraction of Al-7 graphite slurry, rolling speed and interfacial shear strength of bonding plate could be established by artificial neural networks perfectly. This model could be optimized with a genetic algorithm. The optimum bonding parameters are: 516°C for preheat temperature of steel plate, 32.5% for solid fraction of Al-7 graphite slurry and 12 mm/s for rolling speed, and the largest interfacial shear strength of bonding plate is 70.6MPa.

CaSO₄ whisker reinforcing and toughening mechanisms for polyurethane elastomer were studied. The effects of dispersity of CaSO₄ whisker and interfacial bonding state on reinforcement and toughness were discussed. The microanalyses showed that CaSO₄ whisker reinforcing mechanism for polyurethane elastomer mainly was load transferring and its toughening mechanism involved crack deflection and whisker pullout. The results indicated that composites with 5%–10% CaSO₄ whisker exhibited the best mechanical properties. Good bonding interface was formed between whisker and matrix after the surface of CaSO₄ whisker was treated by silane coupling agent. The fairly improved strength and toughness are attributed to the better interfacial bonding state.

The method of controlling separating anode and separating power source was used to perform orthogonal optimization for the parameters in electroplating Zn-Al alloy. The electroplating Zn-Al alloy technology was decided, in which the content of Al is about 12%–15%.

The effects of mineral admixtures on fluidity, mechanical and hydrational exothermic behavior were studied. The results show that, double-adding ways, i e, fly ash and slag were added at the same time, not only improves the fluidity of fresh concrete with low W/B and compensates the lower early compressive strength of harden concrete caused by high adding amount of fly ash, but also greatly reduces the highest temperature rise, exothermic rate and total heat liberation of 3 day of binder pastes in HLPC, and postponed the arrival time of the highest temperature rise. HLPC was prepared and applied to project practice successfully.

By means of “Mortar Bar Method”, the ratio of cement to aggregate was kept as a constant 1∶2,25 the water-cement ratio of the mixture was 0.40, and six prism specimens were prepared for each batch of mixing proportions with dimensions of 10×10×60mm³ at 38±2°C and RH≧95%, the influences of content and particle size of active aggregate, sort and content of alkali component and type of slag on the expansion ratios of alkali-activated slag cement (ASC) mortars due to alkali aggregate reaction (AAR) were studied. According to atomic absorption spectrometry, the amount of free alkali was measured in ASC mortars at 90d. The results show above factors affect AAR remarkably, but no dangerous AAR will occur in ASC system when the amount of active aggregate is below 15% and the mass fraction of alkali is not more than 5% (Na₂O). Alkali participated in reaction as an independent component, and some hydrates containing alkali cations were produced, free alkalis in ASC system can be reduced enormously. Moreover, slag is an effective inhibitor, the possibility of generating dangerous AAR in ASC system is much lower at same conditions than that in ordinary Portland cement system.

A type of recycling agent was developed and its use for modifying used asphalt is described. The results show that the viscosity and three main properties of the aged asphalt were remarkably improved. With 5%–7% content of recycling agent, the main properties of recycled asphalt comported with China GB asphalt standard AH—70 and the recycled asphalt concrete could be used as high-grade highway. Furthermore, the recycling mechanism of the aged asphalt is discussed.

The performances of dry-grinding fine cemenT (DFC) in grouting procedure were experimentally studied. The measurement of its fineness and simulated test for injectability showed that this DFC could be used to inject rock mass with micro-fissure. In order to improve the grouting quality, the water-cement ratio and discarding time of slurry should be controlled precisely. If the water-cement ratio is over 2∶1 in slurry that is made from DFC, it is not suitable to grout. Finally, the influence of different mixing times on strength of hydrated cement made from the DFC is explained by microstructure analysis with SEM.

The smart properties of homogeneous electrorheological fluid (HERF) containing side—chain type liquid crystalline polymer were studied and an actual HERF damper with an adjustable viscosity was produced. A mechanical model of the HERF smart damper was established on the basis of experiment and theoretical analysis. Then a controlled equation of SDOF structure by HERF damper was derived and a semi-active control strategy based on optimal sliding displacement of damper was presented. The simulation results for a single story frame structure indicate that HERF, which may avoid some defects of common particles-suspended ER fluids, is an excellent smart material with better stability. Using the semi-active control strategy presented, HERF smart damper controlled could effectively reduce seismic responses of structures and keeps the control stable at all times.

The relationship between the electrical resistivity of carbon fiber reinforced concrete (CFRC) containing different carbon fiber contents and temperature was studied. it is found that carbon fiber contents influence greatly on the temperature sensibility of CFRC road material. Only with a certain amount of carbon fiber can CFRC show a sensitive and stable temperature sensibility.

A program control was applied in the fuel gas shuttle kiln, and its principle and disadvantge were analyzed. An advanced set point control method, in which the change rate of temperature is the controlled variable, is also described, and the new control system makes the control precision of temperature improved.

The strength of rockmass from two aspects is analyzed. Firstly, the strength of the rockmass is mainly controlled by the critical stress value of rock, and the contribution of joints is to increase the effective stresses of rock and to decrease the damage strength of rockmass according to the macro-damage mechanics of rockmass. Secondly, the strength of rockmass is mainly controlled by the fracture strength of joints. Based on the comprehensive analysis and comparison for the damage strength of rockmass and the fracture strength of joints, a composite damage theory of rockmass may be established.

The properties and tensile behaviors of polypropylene (PP) geogrids and geonets for reinforcement of soil structures are investigated. Mass per unit area of the geogrids and geonets was weighed using an electronic balance and aperture sizes of the geonets were exactly measured using a computer. Laboratory tests were performed using a small tensile machine capable of monitoring tensile force and displacement. Tensile failure behaviors were described, and tensile index properties such as tensile strength, maximum tensile strain, tensile forces corresponding to different strains in the geogrids and gronets were obtained. The characterization of these indexes is discussed.

Based on the principle of Tuned Mass Damper (TMD), the test of a new quake-reduction system was investigated. The main structure of the system is connected with the top floor through Laminated Rubber Bearing (LRB) to make up a huge TMD system-suspended structure. It was shown from the test that the new TMD quake-reduction system can reduce the acceleration of the top floor by more than one quarter if the parameters are chosen efficiently. Since the good effectiveness and easy availability, this system has the practical value in earth quake engineering.

The synthesis and characterization of a series of novel poly (aryl amide imide) s based on odiphenyltrimellitic anhydride are described. The poly (aryl amide-imide) s having inherent viscosities of 0.39–1. 43 dL/g in N-methyl-2-pyrrolidinone at 30°C, were prepared by polymerization with aromatic diamines in N, N-dimethylacetamide and subsequent chemical imidization. All the polymers were amorphous, readily soluble in aprotic polar solvents such as DMAC, NMP, DMF, DMSO, and m-cresol, and could be cast to form flexible and tough films. The glass trsanition temperatures were in the range of 284–336°C, and the temperatures for 5% weight loss in nitrogen were above 468°C.