Advanced Materials Research Vols. 396-398

Abstract: Use ANSYS / LS-DYNA software to build a numerical model for studying influence of projectile’s penetration velocity, penetration angle and ceramic/metal composite structure on protective capacity of multilayer ceramic composite. The results showed that velocity loss range of projectile running through the multilayer ceramic composite decreased with initial penetration velocity of projectile increased and that the shape of bullet hole showed growing asymmetry with penetration angle increased. Anti-penetration capacity of multilayer ceramic composite protective structure is better than that of single-layer ceramic composite protective structure or single-layer homogeneous steel structure with equal quality.

Abstract: The effects of the polyamine chelating agent and nonions surfactant additive on the surface defectivity reduction in the final polishing of the mono silicon wafers were investigated using high-purity nano colloidal silica based organic alkaline slurry. Experimental results reveal that the chemical enhanced silicon final polishing slurry containing FA/O polyamine chelating agent and FA/O nonions surfactant changed the chemistry character of silicon surface, can realize the chemical uniform etch the surface areas with defects and defect-free area, deeply lower the surface microroughness of silicon polished wafer, achieving defect-free with perfect quality of flat mirror-surface.

Abstract: Two low alloy steels were selected. Inclusions in them were analyzed by electronic probe micro-analyzer. The Influence of inclusions in low alloy-steels were discussed by polarization tests and simulated occluded corrosion cell combined with micro-analyse. The results showed that the inclusions in low alloy-steels were the main pitting initiation and the sulfide inclusions were easier to cause pitting corrosion than other inclusions. The inclusions also accelerated pitting corrosion propagating.

Abstract: The acidfied sulfur-prevulcanized natural rubber (NR) latex was mixed with 1～20 parts per hundred rubber (phr) of a 2wt% solution of chitosan (CS) in 1wt% acetic acid, then cast to preapare a series of NR/CS semi-interpenetrating polymer network (semi-IPN) films; the NR/CS semi-IPN films were further treated with 0.5wt% glutaraldehyde（GA）solution for respectively 1, 3 and 6h to obtain NR/CS IPN films. The mechanical properties and swelling behavours in various media of water, toluene and reference olis of IRM901 and IRM 903 of these films were studied and compared with those pure sulfur-prevulcanized natural rubber latex (SNRL) film. Results showed that, NR/CS IPN films with better mechanical properties could be obained by treating the 24h-leached NR/CS semi-IPN films than by treating directly the unleached ones with 0.5wt% GA solution; the tear strength, 300% modulus, Shore A hardness, hydrophilicity and resistance to non-polar solvents and oil of the SNRL films increased with the incorporation of CS, while the NR/CS IPN films exhibited better than the NR/CS semi-IPN films, especially in tear strength enhancement; the tensile strength and elongation at break of NR/CS semi-IPN and IPN films gradually decreased with the increase in CS content. However, most of the elasticity of pure NR vulcanizate could be reserved, when the CS content was not greater than 15 phr.

Abstract: Fluid friction characteristics were experimented and studied on four group narrow annuli with the gap size ranging from 0.50 mm to 2.5 mm which are composed of copper tube and PVC pipe, and distilled water used as working fluid in the experiment. The experimental results show comparing with circular pipe, the narrow annuli advance the Reynolds number from the laminar to the rapids and friction factor goes down with decrease of the gap size. It w as found that the critical gap size of the conventional annuli size and the narrow annuli approximately is 2.5 mm, friction factor increased with the increase of the gap size when the gap is smaller than 2.5 mm.

Abstract: NiO-coupled NiTiO3 nanocomposites have been synthesized by calcining a precursor dodecylbenzensulfonate (DBS) modified Ni-Ti LDH (DBS-Ni5Ti) and characterized by XRD, ICP, TG/DTA, SEM and DRS methods. The results show that the photocatalytic activity is gradually enhanced with increasing calcination temperatures, consistent with the marked increase in the content of NiTiO3 phase. The pentachlorophenol (PCP) degradation percentage over DBS-Ni5Ti-800 is up to 66%. The NiTiO3 phase in the nanocomposites may act as a major one of the photocatalytic active phases in the degradation of PCP under UV-light irradiation.

Abstract: A novel method is proposed to modify montmorillonite with anionic surfactants, cationic surfactants and halides stearyl cationic surfactants made by our group (Z-surfactant). The structure of organophilic montmorillonite (OMMT) was characterized by XRD and TG. The results of X-ray diffraction show that cationic surfactants and anionic surfactants are all intercalated into the layer of MMT. When modified with cationic surfactants, the interlayer spacing of MMT increases from 1.24 nm to the maximum of 3.76 nm. When it was secondary modified, the insertion order is to insert the cation first and then the anion. The interlayer spacing of montmorillonite increases to 4.80 nm, the modification effect is well.

Abstract: A adsorbent for cadmium has been prepared by loading an anion-exchange resin with a novel supramolecular compound named thiacalix[4]arenetetrasulfonate (TCAS). The adsorption properties of Pb²⁺ on TCAS-loaded resin had been studied and the effects of varying temperature, pH value, adsorption time and initial concentration. Batch extraction studies had revealed a high adsorption ability of the TCAS-loaded resin toward this heavy metal ion with high selectivity. The maximum adsorption capacity of the TCAS-loaded resin toward Pb2+ was 26.32 mg•g^-1. The removal rate of Pb²⁺ in water was up to 99% after 40min at 20°C when a 50mL aqueous solution of Pb²⁺ (10 mg•L^-1) was adsorbed by 0.5g TCAS-loaded resin. The removal percentage steadily retained above 99% when the pH values were in the range of 4 to 7. The adsorption isotherm of the TCAS-loaded resin to Pb²⁺ ions fits well to linear form of Langmuir sorption equation.

Abstract: It is of great significance to study on the dislocation density distribution of different types of doped indium phosphide (InP) crystal wafers for fabricating high-quality InP single crystal with low dislocation density. In the paper, a new etched pits density mapping (EPD mapping) measurement is introduced to measure the dislocation density distribution of the S-doped, Fe-doped and non-doped InP wafers pulled by high-pressure liquid encapsulated Czochralski (HP-LEC) technique. Test results show that in the three types of InP wafers， the S-doped InP wafer’s dislocation density is lowest and uniformity is best; the non-doped InP wafer’s dislocation density is maximum and uniformity is the worst; the Fe-doped InP wafer’s dislocation density and uniformity are between the S-doped and non-doped InP wafers. In the paper, the measurement results are analyzed in detail also from the faces of the doping and crystal growth process and thermodynamic mechanism. This study shows that in addition to traditional methods, using reasonable doping process can also effectively reduce the dislocation in the crystal, enhance the lattice strength and improve the uniformity of the InP single crystal.

Abstract: AZO nanometer powders were prepared by combustion synthesis. The influence on the synthesis of AZO nanometer powders were investigated in conditions of using single fuel or dual fuel by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The results showed that the AZO powders were well-distributed with smaller grain size when using dual fuel.