Advanced Materials Research Vols. 233-235

Abstract: Single factor method was used to investigate the effects of the main technical parameters ,which was on the Pd deposition rate in electroless Pd plating process. The kinetic equation of palladium deposition was established. When the concentration of EDTA-2Na was less than 6g/L，V= 0.783 C_A^1.00784 C_B^0.15225 Cc^-0.3373 C_D^0.29417 exp[10.76×10³(T-298)/(298RT)] .When the concentration of EDTA-2Na was more than 6g/L ,V= 2.147C_A^1.00784 C_B^0.15225 Cc^-0.3373 C_D^-0.33376 exp[10.76×10³(T-298)/(298RT)] .

Abstract: Selective laser melting(SLM) is driven by the need to fabricate functional metallic parts and tools with near shape and density. The method of process to fabricate a metal part will save materials, time and energy compared to the traditional manufacturing methods. Unlike the selective laser sintering (SLS), the metal powder particles are molten by the laser beam during the process of selective laser melting. In this paper, IN625 powders were adopted to investigate the characters of single molten track. The factors that affect the surface quality and relative density are the process parameters such as the laser energy, scan speed and so on. They were studied to find out the correlation between the parameters and formation of single-track. It has been found that Optimal ratio between laser power and scanning speed (P/v) is 1-1.5 for IN625 SLM. P/v is the linear energy density. It also has been found that the width and height of single-track can be calculated when the linear energy density is given. In this study the laser power, scan spacing and the hatch spacing which affect the surface quality and the relative density of the metallic parts were optimized.

Abstract: In this article, the antioxidant activity of the crude extract from peanut hulls was tested with phosphomolybdenum complex method, the reduction of K₃Fe(CN)₆ and DPPH assay. The IC₅₀ value for DPPH radical scavenging lied 14.86μg ml^-1, and 28 μg mL^-1 of PHF exhibited total antioxidant activity and reducing power which were comparable to that of the ascorbic acid standard at 52.41 and 15.41 μg mL^-1, respectively.

Abstract: Uniform design was adopted, and two factors, i.e., frozen at different time postmortem with six levels, thawing at different thawing rate with three levels, were considered. Water holding capacity under pressure (WHC), thawing loss (TL) and production rate (PR) were measured to study the different effects of the two factors considered. The results showed: All the two factors considered had significant effects on WHC, TL and PR, and the effects of the two factors on them were nonlinear, there were interactions between the two factors considered. The optimization calculation showed that the later the frozen time postmortem and the smaller the thawing rate was, the higher the production rate of Chinese sausage was.

Abstract: Two types of catalysts, V₂O₅-P₂O₅/SiO₂ and Cs-Sb₂O₅/SiO₂, were separately prepared with SiO₂ as carrier. Their catalytic properties were investigated in the process of synthesizing methyl acrylate through aldol condensation with methylal and methyl acetate, and the influence of the catalyst’s filling up technique on the reaction was studied. Reactions were performed in a fixed-bed reactor. The research results indicate that aldol condensation reaction is effectively promoted when the two catalysts were filled up in appropriate subsections of the reaction tube. Specifically, when V-Si-P Oxide was filled up at the 4^th subsection and Cs-Sb₂O₅/SiO₂ catalyst at the 6^th subsection with the temperature of the reactor at 400 °C and the mol ratio of methyl acetate and methylal at 1.6:1 and the space velocity at 3.2 h^-1, then the conversion rate of methylal was 50.9%, the selectivity of methyl acrylate was 90.63%, and the ester yield of methyl acrylate was 46.15%.

Abstract: Dipping borosilicate glass in modified sol-gel solution was used to prepare thin film TiO₂. The sol was prepared from titaniumtetraisopropoxide(TTIP), hydrochloric acid (conc. HCl), ethanol(EtOH), TritonX-100 surfactant and acetic acid(AcOH). The mole ratios of the starting solution were surfactant: EtOH: AcOH: TTIP: conc.HCl= R: 45: 6: 1: 0.1. The amounts of surfactant (R value) were varied as 0, 0.5, 1, 2, 3 and 4 moles, respectively. After dip-coated, the borosilicate glasses were dried at room temperature and heated for 15 minutes at 500 ^°C (rate3^°C/min). The obtained films were uniform; however, varied in transparency, decreasing when the TritonX-100/TTIP mole ratios had been increased. The crystal structure, optical property and the morphology of thin films TiO₂ were characterized by X-ray diffraction (XRD), UV–Vis spectroscopy, Environment Scanning Electron Microscope (E-SEM) and Atomic Force Microscopy (AFM). Spectra of XRD showed that all the TiO₂ thin films were anatase phase. From UV–Vis technique, it was found that their UV absorption edges were approximately 380 nm. A cracking on the surface of TiO₂ thin films appeared when the amounts of the surfactant were increased. From AFM image, TiO₂ particles were spherical size, ranged from 11.2 to 35.5 nm and the roughness of the films increased with the increasing of TritonX-100/TTIP mole ratios. Under UV illumination, the photodegradation results of Reactive Yellow17 was pseudo the first order reaction and the film of TritonX-100/TTIP mole ratio = 1 : 1 was the highest removal efficiency with the apparent rate constant (k) = 2x10^-2 min^-1 and half life (t_1/2) = 34.65 min.

Abstract: The excited states of methyl methacrylate(MMA) were calculated by CIS method, MMA molecules on the ground and excited states of molecular structures were optimized. The HOMO and LUMO molecular orbitals of MMA molecule are given in the ground state and excited state . The results show that: MMA is excited, the molecular orbital from 27 → 28, the excitation energy is 1.4310eV, Carbon-carbon（C=C）double bonds break.

Abstract: The governing equations of flow of the second-order fluid with variable coefficients through concentric annuli with isometric ring slots on the inner cylinder under the cylindrical coordinate system were established. The governing equations were numerically solved by the finite difference method, the influence of slot width, slot depth, slot interval and slot number on velocity distribution is analyzed. The results show that slot width and slot depth is related with radial velocity, axial velocity and resultant velocity, slot interval is related with radial velocity, which is little related with axial velocity and resultant velocity, slot number is little related with radial velocity, axial velocity and resultant velocity.

Abstract: The waste fluorgypsum was modified and its comprehensive utilization with fly ash in concrete was studied. Eight-channel micro-calorimeter (TAM Air) and scanning electron microscopy were employed to study the basic properties and application performance of the modified fluorgypsum. Experimental results indicated that the modifying made the fluorgypsum crystal staggered mutually and improved the strength of the hardened body. The modified fluorgypsum and fly ash could delay reaction of cement hydration and reduce the heat of hydration of cement. When fluorgypsum was added to the cement, the fluorgypsum beared the function of enhancing the early stage compressive strength of concrete.

Abstract: The photo decomposition of formaldehyde (HCHO) in an air stream in a bamboo charcoal loaded Ce-doped TiO₂ coated photo-reactor was systematically investigated and demonstrated to be effective at relatively short retention times. The TiO₂ loading and the photo-reactor’s structure’s influences on the efficiency of photochemical catalysis degradation of formaldehyde was reviewed. The TiO₂ / bamboo charcoal adsorption of formaldehyde, as well as the influences of a certain amount of formaldehyde after adsorption on its photochemical catalysis effect were discussed. The sol-gel preparation method was used to prepare TiO₂. Compare a series of experiment data, we get: after supported by TiO₂, the surface of bamboo Charcoal still has strong catalysis degradation ability. After adsorbing formaldehyde, the photochemical catalysis degradation efficiency of formaldehyde of the catalyst at steady state is generally the same with pure catalyst. When the thickness of the catalyst layer of the multi-ladder-type structure photo-reactor is 2mm, the interval is 20mm, the best absorption efficiency of formaldehyde of TiO₂ / bamboo charcoal is reached. TiO₂ without doped Ce has no degradation of formaldehyde after 2 hours, but the degradation rate of formaldehyde of the Ce-doped TiO₂ still is 15% 2 hours later, and the formaldehyde decontamination of the equipment reached 94%.