Ammonium metatungstate and cobalt nitrate were mixed at the molecular level in distilled water and then spray-decomposed to CoWO₄/WO₃ nanocomposite powder. The particle morphology, crystalline size, forming course, chemical composition and phase structure of the powder were studied by SEM, TEM, DTA-TG, IR and XRD, respectively. Results show that the powder is homogeneous, spherical and nano-aggregated.

Aligned carbon nanotubes (CNTs) were prepared on Nicoated Ni substrate by microwave plasma chemical vapor deposition (MWPCVD) with a mixture of methane and hydrogen gases at temperature of 550°C. The experimental results show a direct correlation between the alignment of CNTs and the density of the catalyst particles at low temperature. When the particle density is high enough, among CNTs there are strong interactions that can inhibit CNTs from growing randomly. The crowding effect among dense CNTs results in the aligned growth of CNTs at low temperature.

By adopting sodium silicate as a major material, SiO₂ nanoparticles (size in 8–15 nm waterdispersiod was prepared by ion exchanging. The effects of sodium silicate concentration, surfacemodifying time, temperature and technological conditions on their diameter, size distribution and dispersion stability were also studied. The result show that, the hydrophilic lipophlic and hydrophiliclipophilic SiO₂ nanoparticles waterdispersoid can be prepared through different kinds of surfacemodifiers and the optimum reaction conditions have been determined as follows: sodium silicate solution concentration: 8 w%; silicone dosage: 3% of the total mass of nano SiO₂ waterdispersoid; adding way and time of surfacemodifier: continual dropping for 2h; surfacemodifying temperature: 60–70°C.

In the process of particle settling in a dilute, a density graded distribution of the liquid below the suspension needs to be designed according to the gravity of the suspension prior to sedimentation. In the present paper a compositionally graded W-Mo composite was formed via the settling of the W and Mo particles, with a density gradient distributed in the initial clear liquid along the settling direction.

Rectorite, Talc and alumina were used to obtain high-quality cordierite with stoichiometric composition (51.3wt% SiO ₂, 34.9wt% Al ₂ O₃, 13.8wt% Al ₂O₃).The water absorption, apparent porosity, bulk density, thermal expansion coefficient, crystalline phases and microstructure were tested by means of X-ray diffractometer (XRD), scanning electronic microscopy (SEM), Archimedes immersion technique, etc. This work systematically studied the synthesizing process of the cordierite. The result shows that the cordierite can be synthesized at a lower temperature and within a wider temperature range by using the rectorite as clay raw materiah.

The single-phase Ba(Mg_1/3 Nb_2/3)O₃ (BMN) powder was successfully prepared by the KCl molten salt synthesis (MSS) method. The temperature for single-phase BMN powders by MSS was about 400°C lower than that by the solid-phase method. The average particle size (APS) was about 0.91 μm at 900°C and increased with increasing synthesis temperature. Based on the APS, the activation energy for particle growth in the MSS, whose value was 64.1 kJmol^-1, was attained. The sinterability of the powder prepared by MSS method was better than that prepared by solid-phase method.

To determine whether a biodegradable calcium phosphate cement (CPC) provides significant augmentation of pedicle screw fixation or not, an in vitro biomechanical study was carried out to evaluate the biomechanical effect of CPC in the restoration and augmentation of pedicle screw fixation. Axial pullout test and cyclic bending resistance test were employed in the experiment, and polymethylmethacrylate (PMMA) was chosen as control. The results demonstrate that the pullout strengths following CPC restoration and augmentation are 74%greater on an average than those of the control group, but less than those of PMMA restoration group and augmentation group respectively (increased by 126%versus control). In cyclic bending resistance test, the CPC augmented screws are found to withstand a greater number of cycles or greater loading with less displacement before loosening, but the augmentation effect of PMMA is greater than that of CPC.

Nanosized particles of hydroxyapatite (HAP) were synthesized by reacting Ca (H₂ PO₄)₂· H₂ 0 solution complex with equimolar Ca(OH)₂ saturated solution in sodium bis (2-ethylhexyl) sulfosuccinate (AOT)/isooctane water-in-oil microemulsion. The formation of microemulsion strongly depended on water content w (w = [H₂O]/[AOT] molar ratio) and concentration of surfactant and cosurfactant (1-octanol). By the variety of conductivity with w and the partial ternary phase diagram derived from a series of demarcation points, we set the basic component of microemulsions: [AOT] = 0. 1 M(mol/ dm₃), [1-octanol] = 0.1 M and w = 3–9. Dynamic light scattering (DLS), UV-visible absorbance, TEM analysis and X-ray diffraction were used to characterize the microemulsion, formation of particles and resulting HAP particles. At low water content (w < 9), the water pool radius of the droplet in the Ca(H₂ PO₄)₂ · H₂O microemulsion lineally depended on w. The size of final HAP particles was strongly affected by water content w and reactant concentration. With increasing water content w from 3 to 9, the size of HAP particles increased from 10–20 nm to 40–50 nm at reactant concentration [Ca(H₂ PO₄) 2 · H₂ 0] = 12 × 10^-3 mol/ dm³. The resulting HAP particles were poorly crystallized and spherical in morphology.

To improve the osteogenesis ability of a-tricalcium phosphate (α-TCP) bone cement, a novel BMP/ α-TCP composite bone cement was prepared. By measuring the setting time and compressive strength, the hydration characteristic of bone cement was evaluated. Animal experiments including histological observation, radiographic investigation as well as digital image analyses reveal the difference of osteogenesis ability among BMP,a-TCP bone cement and BMP/α-TCP composite bone cement. Results show that α-TCP bone cement possesses excellent hydration and setting properties as well as high mechanical property. Comparison experiments show that BMP/ α-TCP composite bone cement has a stronger osteogenesis ability. The gross observation of the implant site does not exhibit any inflammation or necrosis. Histological analyses reveal that the material has good osteointegration with host bone, and new bone formation is detected within the materials, which are degrading. Strong osteogenesis ability of the composite is due to not only the excellent osteoconductive potential but also the osteoinductive potential contributed by active BMP releasing and the material degradation. Large skull defect could be well-healed by filling BMP/α-TCP composite bone cement. This novel material proves itself to be an absorbable and bioactive bone cement with an osteogenesis ability.

Microstructure of the eco-material combining vegetation recovery with slope protection is important for determining plant-growing properties. Several techniques for analyzing the eco-material microstructwe are presented, including the freeze-cut-drying method of preparing samples for scanning electronic microscopy (SEM), the SEM image processing technique and quantifying analysis method of the SEM images, and etc. The aggregates and pores in SEM images are identified using the different mathematics operators, and their effects are compared. The areas of aggregates and pores are obtained using the operator of morphology, and the influences of different thresholds in image segmentation are also discussed. The results show that the method, in which the variation of non-maximum grey-level gradient is limited, improves the effect of edge detections due to a weak distinction existing at the edge between the aggregates and pores in image. The determination of the threshold should combine the image characteristic with filling operation, so as to assure the precision of the image analysis, in which the contact-segmentation is the simplest and most effective method. The results also show that the pore areas in eco-materials are generally larger than those in the correlative soils, and their increment is large as soil fabric being fine. These differences are related to admixture of expansive perlitic. The operator of morphology provides a new method for the image analysis of other porous material microstructure such as soils and concretes.

Biodegradable polymers have been widely used in the field of tissue engineering. The adhesive characteristic of polymer surfaces must be modified for cell seeding and growth before being used. The modified method poly-β-hybroxybutyric acid (PHB) was introduced and the biocompatibility of modified PHB to adrenocortical cells was studied here, Gelatin was used as a modifier to retrofit PHB and adrenocortical cells were seeded in the modified PHB. The effects of PHB on the proliferation and secreting function of adrenocortical cells were evaluated by MTT and RIA methods. It shows that adrenocortical cells were able to grow and survived in PHB and no influence on the proliferation and secreting function of the cells was observed. The morphology study shows that the modified PHB was easy for cells seeding and growing. The modified PHB is a good biodegradable material as cell carrier for transplantation of adrenocortical cells.

The repairing of damaged composite materials becomes a hot research subject in the late 1990s. In this paper a new technology of repairing composite materials is given on the basis of our previous research. The light wave of 675 nm transmitted by optical fiber is used as repairing light source, special repairable adhesive which can be stimulated by the light is adopted. By comparing the stiffness of the composite material before and after being damaged, it can be concluded that the mechanical property will not be changed with the feasible repairing technology.

Diamond-like carbon (DLC) films have recently been pursued as the protection of MEMS against their friction and wear. Plasma enhanced chemical vapor deposition (PECVD) technique is very attractive to prepare DLC coating for MEMS. This paper describes the preparation of DLC films using twinned electron cyclotron resonance (ECR) microwave PECVD process. Raman spectra confirmed the DLC characteristics of the films. Fourier-transform infrared (FT-IR) characterization indicates the carbon is bonded in the form sp³ and sp² with hydrogen participating in bonding. The surface roughness of the films is as low as approximately 0.093 nm measured with an atomic force microscope. A CERT microtribometer system is employed to obtain information about the scratch resistance, friction properties, and sliding wear resistance of the films. The results show the deposited DLC films have low friction and good scratch/ wear resistance properties.

The effects of rare earths (RE)-Mg-Ti compound modification on the structures and properties of high-carbon high speed steel (HSS) were researched. The impact toughness (α_k), the fracture toughness (K_1c) and threshold of fatigue crack growth (ΔK_th) are tested. The thermal fatigue test is done on a self-straining thermal fatigue tester, the wear test is done on a high temperature wear test machine. The results show that the matrix can be refined by the RE-Mg-Ti compound modification, the eutectic carbides are inclined to spheroidicize and are distributed evenly, the morphology and distribution of eutectic carbides are unproved by appropriate RE-Mg-Ti complex modification. After RE-Mg-Ti compound modification, a little effects can be found on the strength, hardness and red hardness, but the fracture toughness (K_1c) and threshold of fatigue crack growth (ΔK_th) are improved in the meantime, the impact toughness (α_k) is increased by over one time, and the resistance to thermal fatigue and wear resistance at an elevated temperature are remarkably improved.

The adsorption of Cu²⁺ on kaolinite under magnetic field was studied at 25°C. The magnetic effects were investigated by designing the variation of exposure time, magnetic flux density and the method of magnetic exposure. The results from these study show that the magnetic treatment significantly enhance the fraction of adsorption of Cu²⁺, the adsorption of Cu²⁺ by kaolinite increases with the increase of pH value from 2 to 6. Both the magnetic exposure time and the magnetic flux density promote the fraction of adsorption Cu²⁺ on kaolinite.

The Mg₂ Si-matrix thermoelectric material was synthesized by low temperature solid-state reaction. This paper studies the effects of holding time and reaction temperature on the particle size and the properties of the material, and also studies effects of doping elemental Sb, Te and their doping seqence on the properties of the material. The result shows that excessively high temperature and elongated holding time of solid-state reaction are harmful, there is a range of particle size to ensure optimum properties and the doping sequence of Sb or Te without influencing the properties.

The hydrogen content in liquid binary aluminum alloys with 1, 3, 5and 8wt% iron has been determined in the temperature range from 973K to 1103K. The hydrogen content in molten Al-Fe alloys increases remarkably when the temperature of the melt rises to about 1053K. This work indicates that the alloying element iron plays an important role in hydrogen content in superheated Al-Fe alloy melts below about 1053K. The results make it clear that the hydrogen content in the melt aluminum reduces with the increasing element levels. A conclusion is drawn that the degree of gassing in molten Al-Fe alloys is bound up with the properties of oxide film of aluminum alloy melts. The element iron has no effect on the compact structure of oxide film in aluminum melts. The effects of alloying element are theoretically analyzed in terms of Wagner interaction parameter. According to the values of the first order interaction parameter, it is concluded that the interaction between iron atom and aluminum is much stronger than that between hydrogen atom and aluminum, and the addition of the alloying element decreases the affinity of liquid aluminum for hydrogen.

A series of bulk ceramic samples of La_1−x Ca_xMn0₃ and Y_1−x Ca_xMnO₃ was prepared by the conventional solid state reaction method, and the samples of x = 1/3 were investigated particularly. The colossal magnetoresistance phenomenon and the properties of magnetic and transport were studied in detail by the experiments of magnetic susceptibility and low temperature resistance. Small angle X-ray scattering (SAXS) was used to investigate the charge inhomogeneities in our samples at room temperature for the first time, and phase separation and colossal magnetoresistance phenomena induced by charge inhomogeneities above T_c were discovered.

The control using piezoelectric smart moment (PSM) controllers for seismically excited structures was studied. The radical principle of PSM controller was introduced firstly and then the different formulae of control shear force for different structures were derived with the stiffness ratio of columns taken into consideration. With the active control algorithm based on the theory of modem optimal control, this study proposes a simulative computation on the frame structure and mill structure respectively, and the results indicate that the installation of this smart controller with proper parameters can significantly reduce seismic responses of different structures. The optimal parameters of the damper can be identified through a parameter study.

A new-type underwater non-dispersible concrete admixture NDA was prepared, its function mechanism was analyzed, and C40 high performance non-dispersible underwater concrete was manufactured by applying NDA. The results indicate that NDA has a suitable workability, low strength loss, and excellent anti-dispersion; the fresh non-dispersible underwater concrete with NDA has high anti-dispersion, excellent workability such as self-compacting and not bleeding; hardened non-dispersible underwater concrete with NDA has a high strength, high durability such as high anti — abrasion, impermeability and anticorrosion.

The physical and mechanical properties of wet-milling ultra-fine grouting cement were studied, and its microstructure was observed through modern instrumentation analysis such as scanning electronic microscopy (SEM), X-ray diffraction and Hg-intrusion micromeritics. The experimental results indicate that wet-milling ultra-fine cement possesses high rheological properties and groutability. It can be filled densely in cracks of rock and hydrate fully, which may endow hydrated cement with high mechanical strength. Main hydration products of wet-milling ultra-fine cement are poorly crystalline C-S-H(I), acicular AFt and plank-shape Ca(OH)₂. The dense crystal-network structure can be formed in the rock gaps filled with cement paste, but some weak regions exist owing to Ca(OH)₂. The features of micro-pore structure of hydrated wet-milling ultra-fine cement are few big harmful pores, abundant harmless micro pores and little most possible pore radius.

Several different experiments, including freezing-thawing, freezing-thawing + drying-wetting, and drying-wetting, in salt solution and in water respectively, were designed to determine the durability of concrete. The durability damage features of concrete in the above experiments were studied. It is demonstrated that the damage extent of concrete under freezing-thawing and freezing-thawing + drying-wetting in salt solution is larger than that in water. Thus, freezing-thawing and freezing-thawing + drying-wetting in salt solution are stricter and more effective methods to evaluate the durability of concrete in salt-existing environment in cold regions. The damage extent of concrete under freezing-thawing + drying-wetting shows an ultra-superposition effect. The order of concrete durability deterioration degree in these experiments is determined. It shows that effects of multi-damage factors are greater than those of single-damage factor.

Due to a viscoelastic damping middle layer, sandwich structures have the capacity of energy consumption. In this paper, we describe the frequency-dependent property of viscoelastic materials using complex modulus model, and iterative modal strain energy method and iterative complex eigenvalue method are presented to obtain frequency and loss factor of sandwich structures. The two methods are effective and exact for the large-scale complex composite sandwich structures. Then an optimum analysis method is suggested to apply to sandwich structures. Finally, as an example, an optimum analysis of a clamped-clamped sandwich beams is conducted, theoretical closed-form solution and numerical predictions are studied comparatively, and the results agree well.

The induction method of improving the strength of Portland cement by adding fine slag powder, high aluminate component and hydrated paste was investigated through determining the physical properties, hydration heat and pore size distribution, and its mechanism was discussed. The experimental results reveal that a certain content of high aluminate component, fine slag powder and hydrated paste can improve remarkably the strength of Portland cement.

Based on the advantages of the fiber Bragg grating sensing technology, this paper presents a principle of a novel smart concrete with fiber optical Bragg grating sensor, analyses the theory and characteristics, illustrates the key technology and method to make the fiber Bragg grating sensor for the smart concrete, and proves the feasibility with experiments. The results indicate that the smart concrete with fiber Bragg grating sensors is feasible in the structure monitoring and damage diagnosing in the long run.

To improve the rate capability and cyclability of natural graphite anode for Li-ion batteries, a novel modification approach was developed. The modification approach included two steps: (a) high-energy ball milling in a rotary autoclave containing alumina balls, H₃ PO₄ and ethanol; (b) coating with pyrolytic carbon from phenlic resin. The treated graphite shows obvious improvement compared with the original natural graphite in electrochemical properties such as cyclability and rate capability, especially at high current density. The primary reasons leading to the improvement in rate capability and cyclability are that the diffusion impedance of Li⁺ in graphite is reduced due to the fact that P filtered into graphite layers can mildly increase interlayer distances, and the fact that the structural stability of graphite surface is enhanced since the coated pyrolytic carbon can depress the co-intercalation of solvated lithium ion.

The graft polymerization of acrylic acid (A) and acrylamide (B) was carried out onto bi-oriented polyester BOPET corona film. The influence of monomer concentration, reducer concentration and reaction time on the graft polymerization was investigated. The surface tension of the films increased with an increase of monomer concentration, till the concentration of monomer A reached 1.5 × 10^-2 g/mL and the concentration of monomer B reached 4.0 × 10^-2 g/mL. The surface tension of the films reached a maximum value at 7 × 10^-4 M of reducer concentration and subsequently decreased with further increase in reducer concentration. The surface tension of the films increased with the increase of the reaction time apparently within 50min. The grafted corona BOPET films were characterized with IR and XPS. The presence of graft on the film surface was confirmed. The attenuation experiments on grafted corona BOPET films in air at 50°Cand in water were carried out to investigate the persistence of graft polymerization of acrylic acid and arylamide onto BOPET corona films.

The present work considered the capillary micro-flow through a fiber bundle. The resin heights in the fiber bundle as a function of time were used to determine the experimental values of capillary pressure and the permeability by the nonlinear regression fitting method. The fitting curves showed a good agreement with experiments. However, these values of capillary pressure from short-time experiments were much lower than the theoretical results from the Yang-Laplace Equation. More accurate capillary pressure was predicted from the presented long-run experiment.