Natural rubber (NR)/multi-walled carbon nanotube (MWCNTs) composites were prepared by combining self-assembly and latex compounding techniques. The acid-treated MWCNTs (H₂SO₄: HNO₃=3:1, volume ratio) were self-assembled with poly (diallyldimethylammonium chloride) (PDDA) through electrostatic adhesion. In the second assembling, NR/MWCNTs composites were developed by mixing MWCNTs/PDDA solution with NR latex. The results show that MWCNTs are homogenously distributed throughout the NR matrix as single tube and present a great interfacial adhesion with NR phase when MWCNTs contents are less than 3 wt%. Moreover, the addition of the MWCNTs brings about the remarkable enhancement in tensile strength and crosslink density compared with the NR host, and the data peak at 2 wt% MWCNTs loadings. When more MWCNTs are loaded, aggregations of MWCNTs are gradually generated, and the tensile strength and crosslink both decrease to a certain extent.

Carbon nanotube (CNT) filled silicone rubber (SR) composites were synthesized by in situ polymerization. The effect of strain on the electrical resistance of the CNT/SR composites and the structure evolution of CNT networks during tensile deformation were investigated. The results showed that the CNT/SR composites had high sensitivity of resistance-strain response. In a wide strain range (0-125%), the change of resistivity could reach 10⁷, which was closely associated with the evolution process of the conductive CNT-network structure. The volume expansion of the composites in the tensile process led to a gradual decrease in the volume fraction of CNTs with the strain increase. When CNT loading was lower than the percolation threshold, CNT network was in disconnected state with a rapid increase in electrical resistance of the composites. Furthermore, the CNT loading had remarkable effect on the sensitivity of resistance-strain response in the composites.

H⁺-rectorite clay, which was prepared by modifying the raw rectorite with 10% hydrochloric acid at 60 °C for 24 h, was used as an absorbent for removal of methyl blue (MB) from aqueous solutions. The morphology and the structure and crystallinity of the pristine rectorite and the H⁺-rectorite were characterized by scanning electron microscopy (SEM) technique and X-ray diffraction (XRD) technique, respectively. The results showed that the H⁺-rectorite exhibited high adsorption ability than the raw rectorite, and it was found that the removal percentage of MB increased with increasing in adsorbents dose, whereas the adsorption amount q _e (mg/g) decreased. The equilibrium was attained within 30 min in adsorption process, and the maximum adsorption capacity of H⁺-rectorite for methylene blue reached as high as 37 mg/g. Besides, the effect of temperature on the adsorption of MB with H⁺-rectorite was investigated and the equilibrium data were well fitted to Freundlich equations. The H⁺-rectorite absorbent saturated with MB can be regenerated by calcinating at 400 °C for 2 h and the regenerated absorbent still showed higher percentage removal of MB.

Titanium nitride (TiN) films were deposited on Si(100) substrates by laser molecular beam epitaxy(LMBE), and their properties of structure and resistivity with varying N₂ pressure were investigated. The results showed that atomically flat TiN films with layer-by-layer growth mode were successfully grown on Si(100) substrates, and (200) was the preferred orientation. With the increasing of N₂ pressure, the N/Ti ratio gradually increased and the diffraction peak progressively shifted towards lower diffraction angle. At pressure of 0.1 Pa, stoichiometric TiN film was formed which exhibited the characteristic diffraction angle of (200) plane. All films showed high reflectance to infrared spectrum and the films with overstoichiometry and understoichiometry had a higher resistivity owing to the surface particles and lattice distortion, while the stoichiometric TiN film depicted the minimum resistivity, around 19 μΩ·cm.

A novel technique of electroforming with orbital moving cathode was carried out for the fabrication of non-rotating thin-walled parts. This technique features a large number of insulating and insoluble hard particles as a real-time polishing to the cathode. When cathode moves, hard particles polish its surface and provide the nickel non-rotating parts with near-mirror finishing. Morphology, microstructure, surface roughness and micro hardness of deposits fabricated by novel method were studied in contrast with the sample produced by traditional electroforming methods. Theoretical analysis and experimental results showed that the novel technique could effectively remove the hydrogen bubbles and nodules, disturb the crystal nucleation, and refine the grains of layer. The mechanical properties were significantly improved over traditional method. The microhardness of the layer was in a uniform distribution ranging from 345 HV to 360 HV. It was confirmed that this technique had practical significance to non-rotating thin-walled parts.

Whether the immunostimulatory effects of CpG-oligonucleotides (CpG ODNs) could be enhanced by the use of gold nanoparticles (Au-NP) was investigated. The CpG ODNs were modified by the Au-NP (CpG / Au-NP) and their uptake and distribution in murine N9 microglial cells were studied. The immunostimulatory effects of CpG / Au-NP on N9 cells, human B cells and plamacytoid dendritic cells (pDCs) were examined. Results showed that the uptake of CpG / Au-NP in N9 cells was much higher than that of CpG ODNs and CpG / Au-NP localized in the cytoplasm of N9 cells. The amount of TNF-α and IL12p40 in N9 cells was increased greatly by the use of Au-NP. And the amount of IL-6 in B cells and IFN-α in pDCs was also significantly increased, while the activation of B cells was not changed. These results reveal that the Au-NP can be used as a delivery media for the oligonucleotides-based therapeutics.

In order to improve the proton conductivity of hollow silica spheres (HSS)/perfluorosulfonic acid ion-exchange (PFSA) composite membranes as proton exchange membrane, sulfonic acid groups were grafted onto the surfaces of HSS via post grafting methods. TEM images and FT-IR spectra of the obtained sulfonic acid groups modified hollow silica spheres (SAMHSS) illustrated that the sulfonic acid groups were successfully grafted onto the surfaces of HSS. Water uptake and swelling degree of SAMHSS/PFSA composite membranes were found much higher than those of HSS/PFSA membranes due to the introduction of hydrophilic sulfonic acid groups. In a range from 50 °C to 130 °C, the highest conductivity of composite membranes was obtained when 5 wt% SAMHSS was loaded. The maximum conductivity reached 7.5×10⁻² S·cm⁻¹ at 100 °C and 100% relative humidity, even the temperature increased to 130 °C, the conductivity of composite membranes with 5 wt% SAMHSS could reach 3.7×10⁻² S·cm⁻¹ at 100 % relative humidity, while the conductivity of the recast PFSA was only 2.2×10⁻³ S·cm⁻¹.

In order to get foam zinc materials of porous metal electrode, a novel method for preparing foam zinc was proposed, in which the polyurethane foam with diameter of 0.3 mm as substrate was processed by degreasing, roughening, activating, electroless plating and electrodeposition. The main factors affecting the process, such as ZnSO₄ content, temperature, pH value, current density, and electrodes distance, were investigated comprehensively. The optimal process conditions are 250 g/L ZnSO₄, 20 g/L Al₂(SO₄)₃, 40 g/L KAl(SO₄)₂, 30 g/L Na₂SO₄, pH=3.5, 4.0 cm of electrodes distance and 0.04 A/cm² current density at 30 °C. The result shows that adding ultrasonic on the process can elevate the deepening plating ability and current efficiency. Foam zinc material with a high porosity of 92.2% and a three-dimensional network structure can be fabricated by electrodeposition.

The effects of CuO and H₃BO₃ additions on the low-temperature sintering, microstructure, and microwave dielectric properties of Ba₂Ti₃Nb₄O₁₈ ceramics were investigated. The addition of less amount of CuO (< 1 wt%) considerably facilitated the densification of Ba₂Ti₃Nb₄O₁₈ ceramics. Appropriate addition of H₃BO₃ (< 3.5 wt%) remarkably improved the microwave dielectric properties of ceramics. The addition of H₃BO₃ and CuO successfully reduced the sintering temperature of Ba₂Ti₃Nb₄O₁₈ ceramics from 1300 to 1050 °C. Ba₂Ti₃Nb₄O₁₈ ceramics sintered at 1 050 °C for 4 h with the addition of 1.0 wt% CuO and 3.5 wt% H₃BO₃ exhibited good microwave dielectric properties: ɛ _r = 33.74, Q·f = 13 812 GHz, and τ _f = −5.35 ppm/°C at about 5.0 GHz.

The ZrO₂/TiO₂ pillared laponite (Ti-Zr-lap) photocatalysts were prepared with intercalation reaction by supercritical fluid drying (SCFD), and characterized by XRD,TEM, SEM and BET surface area analysis, and the photocatalytic properties of Ti-Zr-lap were investigated by degradation of azo dye acid red B (ARB). The results showed that the ZrO₂/TiO₂ pillared structures in laponite could be formed, with the mass fraction of (Zr⁴⁺+Ti⁴⁺)/laponite (X _m) increasing, the basal spacing and the BET surface area of Ti-Zr-lap significantly increased. The Ti-Zr-lap used as photocatalyst had the advantages of stable and porous layered structure, large surface area with the anatase type TiO₂. Compared with the Ti-Zr-lap dried by air drying, the Ti-Zr-lap dried by SCFD showed better photocatalytic property which was very close to that of P25 TiO₂. Using the Ti-Zr-lap as photocatalyst with the optimum X _m of 0.16 and the calcination temperature of 500 °C, under the conditions of the initial concentration of ARB 20 mg/L, photocatalyst concentration of 1.5 g/L and irradiation time 60 min, the decoloring rate of ARB could achieve 98.3%, indicating that the Ti-Zr-lap had excellent photocatalytic property.

The microwave permeability of laminated composites based on thin FeCoBSi films was under study. The level of permeability increased with increasing of the ferromagnetic inclusions in the laminates. The intrinsic permeability spectra of ferromagnetic inclusion are parametrically reconstructed. The obtained parameters of magnetic resonance were specially analyzed. To avoid the effect of eddy current and to obtain large-volume fractions of ferromagnetic constituent, laminates consisting of alternating FeCoBSi/SiO₂ multilayers and mylar substrates were also investigated. For the same volume fractions of ferromagnetic constituent (8.7%), laminates based on multi-layered films are found to possess higher values of permeability than those based on one-layered films.

The surface infiltrated composite (Ni/WC) layers on gray iron substrate were fabricated through a vacuum infiltration casting technique (VICT) using Ni-based composite powder with different WC particles content as raw materials. The microstructures of surface infiltrated composite layer, the interface structures between surface composite layer and the substrate, the changes of macro-hardness with the increasing of WC content and the micro-hardness distribution are investigated. The infiltrated composite layer includes a surface composite layer and a transition layer, and the thickness of the transition layer decreases with the increasing content of WC. The thickness of transition layer with 20%WC content in the surface infiltrated composite layer was 170 μm which was the thickest for all transition layers with different WC content. The surface composite layer was mainly composed of WC, W₂C, FeB and NiB, along with Ni-Cr-Fe, Ni (Cr) solid solution, Ni (Si) solid solution and Ni (Fe) solid solution. The transition layer was composed of Ni (Cr) solid solution, Ni (Fe) solid solution, Ni (Si) solid solution, Fe (Ni) solid solution and eutectic. The surface macro-hardness and micro-hardness of the infiltrated layer had been evaluated. The macro-hardness of the surface composite layer decreases with the WC content increasing, and the average macro-hardness is HRC60. The distribution of micro-hardness presents gradient change. The average micro-hardness of the infiltrated layer is about HV1000.

A combination of carbon nanotubes (CNTs) and titanium (Ti) modified with TiO₂ nanotubes (TiO₂ NTs) was fulfilled with the aim of improving bioactivity of Ti implant. First, well-ordered TiO₂ NTs were prepared by the electrochemical anodization of Ti in an ethylene glycol electrolyte containing 1 wt% NH₄F and 10 wt% H₂O at 20 V for 50 min, followed by annealing. Then, the carboxylated CNTs were coated onto the TiO₂ NTs using electrophoretic deposition (EPD) technique. The growth of hydroxyapatite (HA) on the samples was investigated by soaking them in simulated body fluid (SBF). The result showed the CNTs-coated Ti with the modification of TiO₂ NTs (CNTs-TiO₂ NTs) was more efficient to induce HA formation than the CNTs-coated smooth Ti (CNTs-Ti). The vitro cell response was evaluated using osteoblast cells (MC3T3-E1). The good cell proliferation and strong cell adhesion could be obtained on the CNTs-TiO₂ NTs. These results indicated that CNT coating on the Ti modified with TiO₂ NTs could be potentially useful for the periodontal ligament combination on dental implants.

Modeling the kinetics of the preparing process is necessary to produce a product with the appropriate particle properties and minimum production cost. Owing to the lackness of crystal size distributor (CSD) information, however, solvent-mediated phase transformation encounters difficulty in modeling the kinetics as compared to solution crystallization. Consequently, a model was established by making the product CSD to move along by horizontal translation to obtain the CSDs of the stable phase in the process of transformation. Then the moment method was used to solve the popular balance equation, and the least square nonlinear regression method was applied to estimate the kinetics parameters. The model has been successfully used to simulate the transformation of CaSO₄·2H₂O to α-CaSO₄·1/2H₂O in an isothermal seeded batch crystallizer with different stirring speeds, and it is beneficial to producing high performance α-CaSO₄·1/2H₂O crystals which have the right particle characteristics.

The interactions of 4-aminosalicylic acid (4-ASA) and surfactants in aqueous solutions were investigated by using UV-Vis spectra and steady-state fluorescence spectroscopy. The results showed that the strongest peak at UV-vis spectra of 4-ASA aqueous solution in the presence of cationic surfactant and cetyltrimethyl ammonium bromide (CTAB) appeared at 206 nm and took a red shift from 206 nm to 221 nm with the increase of 4-ASA concentrations from 0.8×10⁻⁵ to 4.4×10⁻⁴ mol/L. Similarly, the strongest peak at UV-vis spectra of 4-ASA aqueous solution in the presence of nonionic surfactant and polyvinylpyrrolidone (PVP) appeared at 206 nm and took a red shift from 206 nm to 219 nm with the increase of 4-ASA concentrations from 0.8×10⁻⁵ to 4.4×10⁻⁴ mol/L. However, the similar phenomena did not appeared in the presence of anion surfactant, sodium dodecyl sulfate (SDS), the UV-vis spectra of 4-ASA aqueous solution remained the same peak position and the peak value increased with the 4-ASA concentration increase. The results could be attributed to the electrostatic attraction between 4-ASA and CTAB or PVP, as well as the electrostatic repulsion between 4-ASA and SDS. Furthermore, the value of critical micelle concentration (CMC) of surfactants in the presence of 4-ASA was determined with Fluorescence method. The first and second CMC of CTAB was 1.2× 10⁻⁴ M and 2.4×10⁻⁴ M, respectively. The first and second CMC of PVP was 1.2×10⁻⁴ M and 2.8×10⁻⁴ M. SDS realized the multiple micellizations to form multiple CMC.

With a two-phase method, well-dispersed 5.2 nm Ag nanoparticles with narrow size distribution (±0.5 nm) are synthesized. The assembled structures of colloidal Ag nanoparticles on highly oriented pyrolytic graphite (HOPG), silicon chip and microscopic glass have been investigated by atomic force microscopy (AFM). With different spin-coating speeds and concentrations of colloidal silver nanoparticles, various assembly structures could form on those substrates. On HOPG, Ag nanoparticles were absorbed and aligned along single-atom-height step edges to form a linear one-layer structure. And on silicon chip and microscopic glass, one-layer closed packing fractal structure and two-layer closed packing ring were observed respectively.

MgO thin films were deposited on Si(100) substrates by laser ablation under various substrate temperatures (T _sub), expecting to provide a candidate buffer layer for the textured growth of functional perovskite oxide films on Si substrates. The effect of T _sub on the preferred orientation, crystallinity and surface morphology of the films was investigated. MgO films in single-phase were obtained at 473–973 K. With increasing T _sub, the preferred orientation of the films changed from (200) to (111). The crystallinity and surface morphology was different too, depending on T _sub. At T _sub=673 K, the MgO film became uniform and smooth, exhibiting high crystallinity and a dense texture.

Three series of Al₂O₃/Al laminated ceramic matrix composites, named SPA, SPV and HP, were fabricated by different methods. SPA and SPV were prepared using Al₂O₃ slices and Al slurry via screen printing and subsequent heat treatment in air or vacuum. HP samples were made by hot pressing the layered stack of Al foils and Al₂O₃ slices. SEM and XRD were applied to analyze the microstructure and the interlayer crystal phase. The bending strength, fracture toughness and fracture work of the samples made by the three methods were measured and compared. The results show that the composites have much better toughness and higher fracture work than the Al₂O₃ slice. Among the samples made by the three methods, the samples made by hot pressing have the optimum mechanical performance. The displacement-load curves and fracture mechanism were analyzed.

Epitaxial BaTiO₃ films with embedded metallic Ni nanocrystal (Ni-BaTiO₃) were successfully fabricated on SrTiO₃ (001) single-crystalline substrate through the laser molecular beam epitaxial (L-MBE) technique. High resolution transmission electron microscopy (HRTEM) and electron energy loss spectrum (EELS) with Kramers-Kronig analysis methods were employed to characterize the microstructures, elementary distribution and the electron structure of these films. HRTEM results suggested that the structure of BaTiO₃ was tetragonal with lattice parameters of a=0.399 nm and c=0.403 nm. Energy dispersive X-Ray spectroscopy (EDX) confirmed metallic Ni nanocrystal embedded successfully in BaTiO₃ epitaxial films. The Ni-BaTiO₃ composite films were compound of the epitaxial BaTiO₃ (110) layers alternating with Ni NCs array (111) layers. Furthermore, the existence of the misfit dislocations induced by the embedding of Ni nanoparticles was also clearly demonstrated by the HRTEM images. The Ni L_2,3 edges of EELS revealed that Ni NCs in their metallic state were embedded uniformly in the BaTiO₃ matrix. A chemical shift of about 7 eV regarding L₃ edges in the Ni EELS was also observed. The optical band gap of BaTiO₃ in these films was about 3.84 eV, higher than 3.55 eV for pure BaTiO₃ films at room temperature.

The oxide dispersion strengthened copper alloys are attractive due to their excellent combination of thermal and electrical conductivities, high-temperature strength and microstructure stability. To date, the state-of-art to fabrication of them was the internal oxidation (IO) process. In this paper, alumina dispersion strengthened copper (ADSC) powders of nominal composition of Cu-2.5 vol%Al₂O₃ were produced by reaction milling (RM) process which was an in-situ gas-solid reaction process. The bulk ADSC alloys for electrical and mechanical properties investigation were obtained by sintering and thereafter hot extrusion. After the hot consolidation processes, the fully densified powder compacts can be obtained. The single γ-Al₂O₃ phase and profile broaden effects are evident in accordance with the results of X-ray diffraction (XRD); the HRB hardness of the ADSC can be as high as 95; the outcomes should be attributed to the pinning effect of nano γ-Al₂O₃ on dislocations and grain boundaries in the copper matrix. The electrical conductivity of the ADSC alloy is 55%IACS (International Annealing Copper Standard). The room temperature hardness of the hot consolidated material was approximately maintained after annealing for 1 h at 900 °C in hydrogen atmosphere. In terms of the above merits, the RM process to fabricating ADSC alloys is a promising method to improve heat resistance, hardness, electrical conductivity and wear resistance properties etc.

Inconel 718 superalloys deposited by laser solid forming (LSF) were heat treated with solution treatment, intermediate heat treatment (IHT) and two-stage aging treatment in sequence (SITA heat treatment). The effect of IHT temperature on microstructure, tensile property and notch sensitivity of LSFed Inconel 718 superalloy at 500 °C were investigated. As-deposited columnar grains have transformed to equiaxed grains and the grains were refined due to the recrystallization during the SITA heat treatment. It is found that the size and amount of δ phase dispersed at grain boundaries decreased with the increasing of IHT temperature, and δ phase disappeared when the IHT temperature reached 1 020 °C. The ultimate tensile strength (UTS) and yield strength (YS) of smooth samples increased to a maximum when the IHT temperature reached 980 °C and then decreased slightly to a minimum when the IHT temperature was 1 000 °C, and followed by slight increasing again till the IHT temperature reached 1 020 °C, resulted from the competition of precipitation strengthening effect of γ″ and γ′ phase and the grain boundary weakening effect caused by the gradual disappearance of δ phase with increasing the IHT temperature. The notch sensitivity factor (q _e) decreased but still greater than 1 as the IHT temperature increased, which is attributed to the decrease of the size and amount of δ precipitation.

The stability of Ti₂AlN at high pressure of 5 GPa and different temperatures of 700–1 600 °C was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with an energy dispersive spectrometer (EDS). Ti₂AlN was found to be stable at temperatures as high as 1 400 °C under 5 GPa for 20 min, and was proved that it held better structure stability than Ti₂AlC under 5 GPa through comparative experiments of Ti₂AlN and Ti₂AlC (representative compounds of M ₂ AX phases (211 phase)). The reaction process at high pressure had some difference from that at ambient pressure/vacuum, and Ti₂AlN directly decomposed to TiN and TiAl at 5 GPa and 1 500 °C for 20 min. Moreover, the mechanism of phase segregation was discussed. In addition, the behavior of Ti₂AlN contacting with Zr at high pressure and high temperature (HPHT) was also studied.

In-situ TiB₂/7055Al nanocomposites are fabricated by in situ melt chemical reaction from 7055Al-K₂TiF₆-KBF₄ system under high intensity ultrasonic field, and the mechanism and kinetic model of insitu melt chemical reaction are investigated. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses indicate that the sizes of in-situ TiB₂ nanoparticles are in the range of 80–120 nm. The results of icewater quenched samples show that the whole process contains four stages, and the overall in-situ reaction time is 10 minutes. The in situ synthesis process is controlled mainly by chemical reaction in earlier stage (former 3 minutes), and by the particulate diffusing in later stage. The mechanism of key reaction between Al₃Ti and AlB₂ under high intensity ultrasonic in the 7055Al-K₂TiF₆-KBF₄ system is the reaction-diffusion-crack-rediffusion. Furthermore, the reactive kinetic models in 7055Al-K₂TiF₆-KBF₄ system are established.

One-step pretreatment, anodization, is used to activate the polyacrylonitrile (PAN)-based carbon fibers instead of the routine two-step pretreatment, sensitization with SnCl₂ and activation with PdCl₂. The effect of the anodization pretreatment on the graphitization of PAN-based carbon fibers is investigated as a function of Ni-P catalyst. The PAN-based carbon fibers are anodized in H₃PO₄ electrolyte resulting in the formation of active sites, which thereby facilitates the following electroless Ni-P coating. Carbon fibers in the presence and absence of Ni-P coatings are heat treated and the structural changes are characterized by X-ray diffraction and Raman spectroscopy, both of which indicate that the graphitization of PAN-based carbon fibers are accelerated by both the anodization treatment and the catalysts Ni-P. Using the anodized carbon fibers, the routine two-step pretreatment, sensitization and activation, is not needed.

The chemorheological behaviors of a low viscosity epoxy resin system (Huntsman 1564/3486) for vacuum infusion moulding process (VIMP) were studied with viscosity experiments. The dual-Arrhenius rheological model and the engineering viscosity model were established and compared with the experimental data. The result showed that the viscosity in the earlier stage calculated by dual-Arrhenius model were smaller than the experimental data, while the data calculated by the engineering model were larger. Combining the two models together can predict the rheological behaviors of the resin system in a more credible manner. The processing windows of the resin system for VIMP were determined based on the two models. The optimum processing temperature is 30–45 °C.

Hexagonal boron nitride (h-BN) is an important structural material with layered microstructure. Because of the plastic anisotropy, this material shows obvious mechanical hysteresis (nonlinear elastic deformation). There are hysteretic loops at the cyclical load-unload stress-strain curves of h-BN. Consequently, two hot-pressed h-BN cylinders with different textures were studied. The mechanical hysteresis is heavily texture-dependent. The area of hysteretic loop is linearly related with the square of loading stresslevel. Two minor loops attached on the hysteretic loops with the same extreme stresses have congruent shapes. It can be concluded that the mechanical hysteresis of h-BN can be explained by a Kink Nonlinear Elastic model developed from the study of a ternary carbide Ti₃SiC₂.

Single component rare earth phenolates substituted by various alkyl groups have been prepared and the correlation between the aryloxides’ structure and catalytic activity in the ring-opening polymerization of D, L-lactide has also been investigated. The catalytic activity of all rare earth aryloxides, characteristics of the ring-opening polymerization as well as polymerization kinetics and mechanism were investigated. The results showed that both phenolates’ catalytic activities and polymerization characteristics changed regularly, keeping in good concordance with variations in substitutents’ number on phenol and structure of aryloxide ligands. The stronger ability of electron-donation of alkyl groups, the higher catalytic activity. Moreover, the more numbers of substituted alkyl on phenyl ring, the higher catalytic activity. The analyses of polymer ends revealed that the polymerization proceeded via a coordination-acyl-oxygen bond cleavage-insertion mechanism.

Fiber-class modified kaolin and PET have been blended in the twin-screw and granulated to chips containing 4 wt% of kaolin. Non-isothermal crystallization process of kaolin modified polyester was investigated using a differential scanning calorimetry (DSC), and the addition of kaolin enhances either the melting temperature (T _m) or the crystallization temperature (T _c). The morphology of kaolin modified polyester, the melt of which is cooled at different cooling rate, was observed by scanning electron microscope (SEM). The relationship between T _c and cooling rate F was studied. Semi-crystalline phase t _1/2 makes an exponential decline with increasing F, and the higher the cooling rate, the shorter the time of crystallization completion. Non-isothermal crystallization kinetics parameters and the activation energy were calculated, indicating that the higher rate of cooling needs the higher relative crystallinity in the unit crystallization time, the crystallization rate increased while speeding up the temperature reduction, and the activation energy ΔE was calculated to be −204.1566 kJ/mol for the non-isothermal crystallization processes by the Kissinger’s methods.

Polyethylene terephthalate (PET, Dacron) was modified by surface immobilization of hirudin with glutaraldehyde(GA) as coupling reagent to improve the blood compatibility. Hirudin-immobilized PETs were characterized by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The blood compatibility of the PETs was evaluated by platelet adhesion evaluation and fibrinogen conformational change measurements in vitro. The results showed the decrease of platelet adhesion and activation on hirudin-immobilized PET with increasing of glutaraldehyde concentration. Fibrinogen experiment showed that fibrinogen adherence and conformational changes of PET-HRD were less than those of untreated PET, which made the materials difficult to form thrombus. The proper reason of blood compatibility improvement was low interface tension between hirudin-immobilized PETs and blood, as well as blood proteins, and low ratio of dispersive/polar component of the surface energy(γ _sd/γ _sp) and high hydrophilicity.

The anti-inflammatory effect and mechanism of Usnic acid (UA) were explored on lipopolysaccharide (LPS)-stimulated RAW264.7 cell line. The effects of UA on pro-inflammatory cytokines including tumor necrosis factor-alfa (TNF-α), interleukin-6 (IL-6) and interleukin-1 beta (IL-1β), pro-inflammatory mediators such as nitric oxide (NO), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were studied by sandwich ELISA, real-time PCR and western blot analyses. Similarly, the effect of UA on anti-inflammatory cytokine interleukin-10 (IL-10) and anti-inflammatory mediator heme oxygenase-1 (HO-1) were also studied following the same methods. Furthermore, nuclear factor-κB (NF-κB) was assayed by immunocytochemistry. The results showed that UA has anti-inflammatory effect by down-regulatinng iNOS, COX-2, IL-1β, IL-6 and TNF-α, COX-2 gene expression through the suppression of NF-κB activation and increasing anti-inflammatory cytokine IL-10 and anti-inflammatory mediator HO-1 production.

A new form of foam cement was produced by mixing alkali-activated slag, clay, a small amount of polypropylene fibers with prepared foam during stirring. The preparation of the material is quite different from the normal one, which is produced just at room temperature and without baking. The fabrication of this energy-saving and low-price material can be favorable for lowering carbon emission by using recycled industrial wastes. Thermal conductivity of 0.116 W/(m·k), compressive strength of 3.30 MPa, flexural strength of 0.8 MPa and density of 453 kg/m³ can be achieved after 28 days aging. The hydration product is C-S-H with less Ca(OH)₂, calcium aluminum and zeolite, which was characterized by X-ray diffraction(XRD) measurement. This prospective foam cement may be expected to be an excellent economical energy-saving building material.

The electrical resistivity of concretes with various aggregate volume fractions (V _a) of 0%–70% at water/cement (W/C) ratios of 0.4 and 0.5 during 1 day was monitored. It is found that the addition of normal aggregate to cement paste leads to a regular increase in concrete resistivity at each hydration stage and the electrical resistivity has a deeper increase for the lower W/C at a fixed aggregate volume fraction. The number of normalized resistivity (NR) of concrete to its paste matrix was introduced, which is only a function of aggregate volume fraction (V _a). The quantitative relationships give an alternative method for the prediction of aggregate volume in the concrete. A logarithmic relation is established between the elastic modulus of concrete at 7 days or 28 days and the electrical resistivity of concrete at 1 day. The equations are obtained, the compressive strength of concrete at 7 days or 28 days can be determined by the electrical resistivity of concrete at 1 day and the used aggregate content in the concrete. The quantitative relationships give a non-destructive test (NDT) method for prediction of concrete elastic modulus and compressive strength.

Clinker has long been regarded as a critical factor for cement hydration and solidification. α-C₂S and β-C₂S in 2CaO·SiO₂(C₂S) phase and C₃S Monoclinic 1(C₃S M1) and C₃S Monoclinic 3 (C₃S M3) in 3CaO·SiO₂ (C₃S) phase were clearly recorded in the ²⁹Si MAS NMR spectra. The content of C₃S phase in the clinker deduced from the fine peak analysis coincides with the phase quantification analysis calculated by the Taylor-Bogue method based on XRF, which also accords to the statistical data in industrial production. NMR provides a proof that C₃S M1 and β-C₂S phases have a prior reaction in the early age hydration of clinker, and demonstrates that aluminum coordination changes from tetracoordinated 4CaO·Al₂O₃·Fe₂O₃(C₄AF) to hexacoordinated [Ca₂Al(OH)₆](SO₄)_0.3·3H₂O(Aft) in one day hydration and changes to the 3CaO·Al₂O₃·CaSO₄·nH₂O (Afm) in a seven-day hydration.

2D, 3D chloride ion concentration at the edge and corner zones were systematically investigated for fly ash concretes made with different cement replacement percentage by fly ash (0%, 10%, 20%, 40%, 60%), water to binder ratios (0.3, 0.35, 0.4), and curing ages (28 d, 90 d). An interaction effect caused by 2D and 3D diffusion could obviously be observed through the comparison with 1D testing results. In order to quantify the interaction effect, 2D and 3D diffusion interaction coefficients was proposed in this paper. Finally, the changes of 2D and 3D interaction coefficients with the change in the free chloride ion concentration were given. The above research provide an insight into chloride ion attack on the edge and corner reinforcing bars of concrete structures in the field of civil engineering.

The compressive strength development of Portland cement pastes was investigated by the electrical resistivity method and the maturity method. The experiments were carried out on the cement pastes with different water-cement ratios at different curing temperatures. The results show that the application of the maturity method has limitation to obtain the strength. It is found that both of the compressive strength and the electrical resistivity follow hyperbolic trend for all the mixes. The hyperbolic equation of each mix is obtained to estimate the ultimate resistivity value which can probably be reached. The relationship between electrical resistivity and compressive strength of the cement pastes is established based on the test results and interpreted by the empirical Archie equation and a strength-porosity equation. The relationship between the electrical resistivity after temperature correction and the compressive strength was linear and independent of curing temperature and water-cement ratio.

Leaching is one of the major factors that alter the mechanical properties of cement-based composites. This study is aimed to investigate the effect of leaching on the properties of cement-based composites. Specimens with two water/cementitious ratios and two mineral admixtures were tested. An electrical potential was applied to accelerate the leaching process. Compressive strength test, scanning electronic microscopy, thermogravimetric analysis and X-ray diffraction analysis were conducted. Test results demonstrated that the calcium leaching reduced compressive strengths of concrete specimens, and such effect was prominent on the specimens without mineral admixtures. The leaching resistance increased with a decrease in water/cementitious ratio and an increase in amount of mineral admixtures. The mineral admixtures would reduce the amount of calcium hydroxide and refine the pore structure through pozzolanic reactions. A fair relationship was found between the calcium leaching and the compressive strength.

The compressive strength developing process and the microstructure of cement-asphalt mortar (CA mortar) were investigated. The fluidity of CA mortar has a great influence on its strength. The optimum value of spread diameter of slump flow test is in the range of 300 to 400 mm. The compressive strength of CA mortar keeps a relatively high growth rate in 56 days and grows slowly afterwards. The residual water of hydration in CA mortar freezes under minus environmental temperature which can lead to a significant reduction of the strength of CA mortar. Increasing A/C retards asphalt emulsion splitting and thus prolongs the setting process of CA mortar. The hydration products of cement form the major structural framework of hardened CA mortar and asphalt is a weak phase in the framework but improves the viscoelastic behavior of CA mortar. Therefore, asphalt emulsion should be used as much as possible on the condition that essential performance criterions of CA mortar are satisfied.

Composite Portland cement (PC) played an important role in various kinds of construction engineering owing to low hydration heat, low-cost, and application of solid industrial waste, but its brittleness and low strength limited its use in stress-bearing locations. The aim of this study is to improve the toughness and fracture resistance by incorporating CaCO₃ whisker in cement matrix. Effect of different content of calcium carbonate whiskers on the mechanical properties of PC was investigated. The results showed that the flexural strength, impact strength and split tensile strength were increased by 39.7%, 39.25% and 36.34% at maximum, respectively. Microstructure and elements of the whiskers in hardened cement were observed and analyzed by SEM/EDS. The mechanisms of the reinforcement of CaCO₃ whisker on cement were also discussed, and the conclusion was that the improvement could be correlated to energy-dissipating processes owing to crack bridging, crack deflection, and whisker pull-out at the crack tips.

The strength curves of lightweight aggregate concrete (LWAC) were tested based on detecting LWAC with density of 1 400–1 900 kg/m³ and LWAC with strength grade of LC15–LC50 by rebound method and ultrasonic-rebound combined method. The results show that the common measured strength curves tested by above two methods can not satisfy the required accuracy of LWAC strength test. In addition, specified compressive strength curves of testing LWAC by rebound method and ultrasonic-rebound combined method are obtained, respectively.

The advanced temperature and stress test machine was introduced to determine the early cracking tendency of concrete with inclusion of light-burnt MgO under full restraint by tracking the development of thermal, physical and deformation properties. Results showed that light-burnt MgO being incorporated ranging between 4 wt% and 6 wt% of cementitious materials was beneficial to increase the maximum compressive stress and cracking stress of concrete by 0.37 MPa and 0.2 MPa on average respectively. The second zero stress temperature was reduced by 11.4 °C and the maximum temperature was slightly reduced while cracking thermal impact was significantly enhanced from 59.8 °C to 66.2 °C. Sensitive anti-cracking coefficient F was forwarded to assess the early cracking tendency of concrete and the inclusion of 4 wt% light-burnt MgO with activity of 109 s ranked the best in crack resistance.

The mechanism of activator to fluorgypsum and the fluorine solidification were investigated by the performances of composite binding material. Through the setting time testing of fluorgypsum with NaOH, Na₂SO₄ and NaF, the least activator dosage were all 1%. And the cementitious material over 80% of fluorgypsum was processed to improve its quality with slag, fly ash and clinker. The maximum compressive strength of composite binding material was over 12.90 MPa in 28 days, and the concentration of fluroride reduced 64.7% which compared with the pure fluorgypsum binding material. Analysis of X-ray diffraction and scanning electron microscopy images showed that ettringite crystals, dihydrate gypsum crystals and C-S-H gel were filled with each other. The unreacted CaF₂ crystals were embedded by a great deal of network and filamentous C-S-H gel. It was the main reason that the composite binding material strength improved, water resistance increased and leaching toxicity reduced.