Advanced Materials Research Vols. 989-994

Abstract: Conventional pesticide applications repeatedly failed to adequately control mosquito and sandflypopulations in desert areas, due to effects of either intense heat, blowing sand, ultraviolet light and/or combinations of them under severe environmental conditions. Application of citral oil to the skin provides temporary relief from pests only until the volatile terpene evaporates or is photodegraded by light. It would be advantageous to encapsulate the citral into a solid or waxy polymer that would slowly release a constant stream of citral from reservoir of the naturally occuring pesticide dissolved in the solid polymer. Polysilsesquioxanes have already proven to block UVB and are known to be oxidatively robust. In this study, a solid polysilsesquioxane pesticide delivery system was prepared free radical polymerization of an oligovinylsilsesquioxane in the presence of citral.The molecular consequences of the free radical polymerization were analyzed by MALDITOF spectrometry and the UV absorption properties of the resulting polymer-citral solution were measured by scanning spectrophotometry (SSP).

Abstract: In this study, the optimum reaction conditions of preparing bridged monomer by dodecylamine (DDA) and of γ-(2,3-epoxypropyl) trimethoxysilane (GPMS) were obtained at 60°C water bath for 36h. The synthesized materials were characterized by infrared spectroscopy (IR), atomic force microscopy (AFM), Scanning Electron Microscopy (SEM) and water contact angle (CA). The result of FTIR indicates the formation of the DDA and GPMS bonded reactions during the synthesis of monomer, and preparation of the skeleton structure. Characterization of AFM on the structure of the surface morphology of the acid-catalyzed materials indicates the formation of layered structure. The acid-catalyzed materials were characterized by SEM indicates the rough structure of micron-level, which was conducive to the hydrophobic properties of the material.

Abstract: In this study, we report the first example of a fullerene-like cage, a stable hedgehog buckyball (HBB). The HBB preparation can be performed using a normal hydrolytic condensation which we previously produced based on [(3-methacryloxy) propyl] trimethoxysilane (MPMS). MPMS was also used as a precursor for this study, but a longer condensation time was employed to produce more viscous products with a larger molecular weight (denoted MPOSS or MSSO).A high-symmetry complete POSS formulated as R₆₀Si₆₀O₉₀ or T₆₀ (T=RSiO_1.5). The MSSO characterization can be determined by FTIR and GPC and NMR and is assigned from the peaks of UV-MALDI-TOF MS.

Abstract: Under the laboratory conditions, the effect of temperature (10, 15, 20, 25, 30°C) on growth and biochemical composition of Sargassum muticum was studied, the results showed that: the optimum growth temperature of S. muticum was 15 °C in the range of 10-30 °C; the contents of chlorophyll a, carotenoid, soluble protein, soluble sugar and brown algae polyphenols were the highest at the temperature of 25 °C, it was speculated that these components appeared compensatory increase duo to the high temperature stress. The contents of these biochemical components were the lowest at 30 °C.

Abstract: The excessive residual stress induced by quenching in steels will easily result in distortion and failure of parts. In order to obtain the more suitable quenchant, quenching process of Cr12MoV steel with different mediums involving water and oil are simulated, respectively. In present paper, the influence of nonlinear surface heat transfer coefficient, thermodynamic parameters and latent heat are considered comprehensively. The distribution of temperature, microstructure, hardness and residual stress after quenching for Cr12MoV steel are simulated by DEFORM finite element software. According to the results mentioned above, the variations of each field of the steel are analyzed.

Abstract: CaS:Eu²⁺ phosphors were prepared by two steps method at a relatively low temperature (1050°C) using NH₄Cl as a flux. The influences of NH₄Cl flux concentrations on the crystal structure, morphology and photoluminescent properties of CaS:Eu²⁺ phosphors were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence (PL), respectively. XRD analysis shows that when the raw materials added with the NH₄Cl flux, the crystal structure was not changed .The SEM images indicate that increase of the NH₄Cl flux enlarged the grain size of the phosphor particles. The luminescence intensity of CaS:Eu²⁺ was enhanced with adding NH₄Cl flux and up to the maximum emission intensity when the addition of NH₄Cl flux is 1wt%.

Abstract: Multi-elements doped LaCoO₃-based mixed conductors La_0.7Sr_0.1Ca_0.1Co_0.8Fe_0.2O_2.9 (LSCCF-112) and La_0.7Sr_0.2Ca_0.1Co_0.7Fe_0.3O_2.85 (LSCCF-213) were synthesized by conventional solid state reaction (CSSR). The forming process, microstructure and crystal structure of the prepared samples were analyzed by TG/DTA, SEM and XRD. The mixed conductivities of the samples were measured using DC four-terminal method in 150-950 °C. Thermal expansion coefficients (TEC) of the samples were tested in 20-950°C. LSCCF-112 and LSCCF-213 exhibit pure perovskite phase and porous structure after sintered at 1200 °C. The average TECs of LSCCF-112 and LSCCF-213 are 18.17×10^-6 K^-1 and 17.52×10^-6 K^-1 respectively. The mixed conductivity of the samples shows semiconducting behavior up to 700-750°C and then decreases as the temperature is further raised. At intermediate temperature (IT), the conductivity values of the samples are both much higher than 100 S/cm.

Abstract: Plasma powder spray welding method is used for depositing successive layers of metal, which forms a 3-Demensional (3D) solid component. Fe45 alloy powder is chosen to spray welding on Q235 steel. Welding process parameters of plasma powder spray welding are studied, which affected the performance of carbon steel weld layer. Then changes of alloy powder spray welding and influences of weld microstructure after spray welding are analyzed. Experiments results show that in the case of only changing transferred arc current, the microstructure and mechanical properties of the weld is obviously better, grain size distributes uniformity, and hardness is moderate.

Abstract: To improve bioactivity of gradient bioceramic coating, the coating with two kinds of rare earth oxide was produced by wide band laser cladding technique. As the experimental results, whichadded0.6wt.% La₂O₃ fixedly, and increased the addition amount of the CeO₂, when the addition of CeO₂fulfill 0.4wt.%, the amount of HA-β-TCP is the largest in this experiment. Soaking the specimens in SBF for 14 days, the coating blended 0.6wt% La₂O₃ and 0.4wt% CeO₂, then a great quantity of Ca-P white particles can be found on coating, which confirmation this bioceramic coating is of best bioactivity.

Abstract: The air-conditioning/cotton blended fiber was pretreatment to investigate the effects of the sodium hydroxide, hydrogen peroxide, scouring agent, tea saponin, oil removing agent, the processing temperature and the processing time on the fabric. The values of capillary, strength, whiteness were got after single factor tests. The results showed that the best pretreatment process was at 90°C, tea saponin 4g/L,oil removing agent 3g/L and the processing time 30min.Through this process, the strength of the fiber was 165cN, the whiteness was 71.2% and the capillary is 10cm.Tea saponin is a main factor only second to temperature.