Advanced Materials Research Vols. 183-185

Abstract: The effect of different tillage systems on the soil organic carbon (SOC), active organic carbon (AOC) and remaining organic carbon (ROC) were studied in a long-term experiment in Chongqing, China. The experiment included five tillage treatments, which are conventional tillage with rice only system (DP), conventional tillage with rotation of rice and rape system (SH), no-till and ridge culture with rotation of rice and rape system (LM), no-till and plain culture with rotation of rice and rape system (XM) and tillage and ridge culture with rotation of rice and rape system (LF), respectively. The results showed that the content of SOC declined as the soil depth increased, and presented obvious surface enrichment phenomenon under the no-tillage systems. The order of SOC, AOC, ROC and ROC/SOC in the 0–60 cm soil layer under different tillage systems was LM (22.74 g kg-1) > DP (14.57 g kg-1) > XM (13.73 g kg-1) > LF (13.10 g kg-1) > SH (11.92 g kg-1), DP (3.67 g kg-1) > LF (3.49 g kg-1) > LM (3.28 g kg-1) > XM (3.17 g kg-1) > SH (2.69 g kg-1), LM (18.09 g kg-1) > DP (10.34 g kg-1) > XM (10.12 g kg-1) > LF (9.20 g kg-1) > SH (8.80 g kg-1) and LM (85%) > SH (78%) > XM 77%) > LF (75%) > DP (74%). Compared with other systems, LM significantly increased SOC, ROC and ROC/SOC, which indicated long-term LM system performed good effect for carbon sequestration.

Abstract: The bundle/matrix interfacial strength in carbon/carbon composites was evaluated via the fiber-bundle pushed-out method. The determined data having a certain difference resulted from different interface fracture behavior via the analyses of the load-displacement curves of the loaded bundles and the observations of SEM images of the pushed-out bundle surface and its bundle/matrix interface. In order to better research bundle/matrix interface properties, Micro-CT was adopted to analyze bundle/matrix interface structure in c/c composites with nondestructive method, and its 2D and 3D images of real interfacial structure were obtained. Thus, the bundle pushed-out method, SEM and Micro-CT are better analysis and characterization methods of interfacial properties at bundle/matrix interface.

Abstract: Novel Kraft fiber reinforced unsaturated polyester (UPE) composites were prepared at various molding pressures in order to investigate the effects of molding pressure on resin content, the mechanical properties and creep resistance. The results indicated that the novel composites had much higher mechanical properties and better creep resistances than traditional wood plastic composites because of the applications of strong Kraft fibers as reinforcement and thermosetting UPE as matrix. Molding pressure had various effects on the many properties of composites. With molding pressure increased from 6MPa to 25MPa, the mechanical properties and creep resistances increased gradually until about 20MPa and then decreased, which were attributed to the different interface adhesions between UPE resin and Kraft fibers at various molding pressures as evidenced by DMA analysis. Benefited from the use of low-viscosity UPE resin, the resin content of Kraft fiber reinforced UPE composites could reduce to 28.3% while strength and creep resistance were still much better than that of the thermoplastic wood-plastic composite (WPC) with 40% polymer matrix.

Abstract: The effects of titanium modification, which was added along with the pouring liquid in ladles, on the hardness and its distribution of cast steel ZG45 smelted in intermediate frequency induction furnace were studied. Titanium modification increased the hardness of cast steel effectively. By scanning electron microscope (SEM) and energy disperse spectroscope (EDS) analysis, it was found that TiC, acting as heterogeneous nuclei, could refine the structure grains, causing the serious crystallographic lattice distortion. So the hardness increased. Proper content of titanium prompted more even hardness distribution across the whole temperature front section. However, overdoes titanium modification easily caused mass nitrides or oxides, which kept solid phases with high meting point in metal liquid to cause difficulties in metal liquid filling and shrinkage, resulting in less concentrated shrinkage cavity and serious structure rarefaction. The hardness ratio between that of internal and external with overdose titanium modification decreased instead compared to that of none modification.

Abstract: By the macroscopic tensile tests of the 3D four-directional braided composites, the failure pattern and fracture morphology of specimens with different geometric sizes have been observed. It is obtained that the different failure mechanisms and the material properties are relevant to the geometric sizes of samples under tensile states. The elastic properties of the braided composites are obtained by volume average method. The variation of shear modulus and Poisson ratio is obtained as well. It is shown that the elastic modulus increases with the increase of number of interior cells. The predicted results are in agreement with the experimental results. The results may provide experimental basis for further study on strength prediction and the establishment of strength criterion for 3D four-directional braided composites.

Abstract: By the Langmuir-Blodgett(LB) technique, the zinc ion containing multilayer was prepared by transferring the zinc acetate, spread on the surface of subphase of ultrapure water and stearic acid-chloroform mixtures, onto a hydrophilic silicon wafer or glass plate. Then the multilayer was converted into ZnO ultrathin films after pre-heating and annealing. The optimized parameters for monolayer formation, such as concentration of subphase, barrier speed and spreading volume, were determined by the measurement of the surface pressure-surface area (Π-A) isotherms. The expended areas after deposition with zinc ions inferred the interaction of stearic acid with zinc ion during the formation of monolayer at air-water interface. The optimized parameters for multilayer deposition, such as surface pressure and lifting speed were determined by the measurement of the transfer coefficient. The X-ray diffraction(XRD) was used to investigate the crystal structures of ZnO nanoparticles and ultrathin film. The surface morphologies of the LB multilayer and ultrathin film were observed by the atomic force microscopy (AFM). A uniform and flat surface of ZnO ultrathin film within nanometer ranges(<35nm) were obtained.

Abstract: The photoelectrocatalytic activation and semiconductor character parameter have been investigated by the electrochemical impedance spectroscopy (EIS) and Mott-Schottky test on the Ti/TiO2 photoanode in ammonia system. Based on the evolution of electrical parameters of the equivalent circuit, the most probable dynamics has been stated that the redox reaction in the Ti/TiO2 film photoanode interface is the main rate-determining step. According to the products analysis, the reaction mechanism of ammonia degradation by TiO2 has been presented.

Abstract: A nonlinear waves equation of an elastic circular rod taking account of finite deformation and transverse Poisson effect is derived by means of Hamilton variation principle in this paper. Nonlinear wave equation and corresponding truncated nonlinear wave equation are solved by the hyperbolic tangent function and cotangent function finite expansion method. Two different types of exact traveling wave solutions, the shock wave solution and the solitary wave solution are obtained. The necessary condition of these solutions existence is given also.

Abstract: The SiOx thin films were deposited by RF magnetron sputtering physical vapor technology on the substrates of 20μm polyethylene terephthalate（PET）, using a pure SiO2 target. An L15 (33) orthogonal experiment was designed with three factors and three values including deposition time, sputtering power, sputtering pressure. Using OTR test the effect of process parameters were researched. The primary and secondary sequence of the design parameters were acquired by the quadratic multinomial. The result showed that deposition time affected more strongly the OTR of the films than the sputtering pressure, the sputtering power affected least between them. The best SiOx thin films were prepared at a deposition time of 27.9min，a sputtering power of 1825W，a sputtering pressure of 0.3455Pa. The calculated OTR was 0.8387 cc/(m2×day)，which was consistent with the test one.

Abstract: The aim of this study was to define that the expression of inducible nitric oxide synthase (iNOS)in cell blocks from ascites was a certain value to evaluate hepatopulmonary syndrome(HPS). iNOS can stimulate the liver and lung to produce excess NO. Excessive production of NO can cause pulmonary vasodilatation and impaire arterial oxygenation. HPS is characterized by shortness of breath and hypoxemia caused by impaired arterial oxygenation due to pulmonary microvascular dilatation in patients with liver disease or PTH. Therefore.the positive rates of iNOS was a certain value to evaluate the conditions of HPS.