Advanced Materials Research Vols. 415-417

Abstract: Abstract：preparation fulvic acid(FA) from lignite in particular process，fulvic acid- phenol-formaldehyde foams(FAPF) were synthesized using the FA as the replacement of phenol at varying ratios from 15-60 wt.%. The effects of foaming agent (dichlormethan)，surface active agent(tween-80) ，curing agengt(hydrochloric acid and phosphoric acid 1:1wt/wt), foaming temperature and FA amount on the property of foam were determined.Curing and foaming were synchronized when foaming agent was 2-6wt.% of the resin, surface active agent was 3-4wt.%,curing agengt was 12-16wt%,foaming temperature was 70-80 °C and FA less than 40wt.%. structure and characterized performance analysis of FAPF Through the Fourier infrared spectroscopy (IR), thermogravimetric (TG) and compressive strength. The results show that: FA could be used as a very good material of partly replace phenol.

Abstract: Optimum amount of rare earths (RE) for treating potassium titanate whiskers (PTW) surface and effects of different PTW contend on tribologieal behavior of Polytetrafluoroethylene (PTFE) composites under dry friction condition were investigated．Worn surfaces were observed and analyzed by scanning electron microscope(SEM)．Experimental results showed that the friction coefficient of PTW/PTFE composites increased with the content of PTW increasing, and the composites performed the best wear resistance occurs at 5wt% PTW content. Moreover, the composites filled with treated PTW performed the best wear resistance occurs at 0.2wt% rare earth content. Under dry friction condition, PTFE composites filled with treated PTW exhibit better tribologieal performance than those of the PTFE composite filled with untreated PTW did. Rare earth elements acting as surface modifier of PTW can increase interfacial adhesion and toughness between PTW and PTFE matrix, and it improves tribologieal performance of the composites．

Abstract: Erosion soil loss is an important problem to be solved. Polyacrylamide (PAM), a biodegradable polymer, has been used in irrigating ditch to reduce soil loss for a long time. It can also be used as an aggregate agent to keep the balance of soil water. The performance of PAM as a soil aggregate agent of silty clay loams was conducted by the wet-sieving method in this study. The effects of PAM on the germination and growth of Bermuda and Bahia were observed. The experiments were conducted in a controlled box with constant temperature and humility. An out-door experiment was also conducted to understand the germination rate of seeds and the development of roots of grasses in ambient condition. Experimental results showed that the addition of PAM would delay the germinations of seeds. However it could enhance the growth of the Bermuda and Bahia grasses.

Abstract: The present study described the effect of the starting NCO/OH molar ratio on the structure and properties of castable polyurethanes based on polytetrahydrofuran glycol (PTMG) and 2,4- toluene diisocyanate (TDI). The structural was tested by SEM. The result showed that higher starting NCO/OH molar ratio can lead to higher degree of microphase separation, decrease the compression set and improve the dynamic mechanical properties.

Abstract: Miscanthus is a highly productive, rhizomatous, C4 perennial grass that should be considered as an excellent active carbon precursor. This paper compares the charcoal characterization and chemical composition between M. sinensis and M. floridulus. Species differed in water content, hot water extract, 1% NaOH extract, organic solvent extract, cellulose, lignin and ash. Carbonization temperatures have effects on charcoal yields of Miscanthus, which ranged from 23.5% to 48.0% for M. sinensis and 11.3% to 37.2% for M. floridulus. Water content, charcoal density, pH value, and specific surface area of charcoal characterization varied between two species of Miscanthus. The specific surface area increased with the increase of carbonization temperature. The highest specific surface area of M. sinensis and M. floridulus was 351.74 m² g⁻¹ and 352.74 m² g⁻¹, respectively, when the carbonization temperature was 800°C.

Abstract: Novel salt-resistance superabsobent microspheres based on acrylamide (AM), 2-acrylamido-2-methylpropane sulphonic acid (AMPS) by inverse suspension copolymerization using ammonium persulfate (APS) as the initiator and N,N-methylene bisacrylamide (MBA) as the crosslinking agent and surfactant PVA as disperse agent are prepared. The experimental results of salt-resistance superabsobent microspheres show the salt absorbency decreased with the increase of salt concentration; The maximum salt absorbency is 132g/g within 75min in 0.9% NaCl solution and the effect of calcium ion on salt absorbency is much greater than that of sodium ion. FTIR indicates the structure of the acrylamide and 2-acrylamido-2- methylpropane sulphonic acid copolymer. SEM indicates that the number of the micropores largely decreased with the water/oil ratio increasing from 4% to 10%. Elemental analysis indicate that the measured values of carbon, sulfur, nitrogen, hydrogen four elements is very close to theoretical value.

Abstract: In this paper, self-assembled monolayers (SAMs) of stearic acid (SA) surface treatment on pure magnesium were studied to improve bioactivity and corrosion resistance of pure Mg. Three pre-treatment methods (HCl-NaOH treatment, alkali-heat treatment and heat treatment) were used. SAMs treated samples were soaked in simulated body fluid (SBF) and untreated samples were taken as control. The pH variation of SBF solution was examined everyday. The electrochemical property of treated and untreated samples was tested to evaluate the anticorrosion performance of organic surface layer. Scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analysis were performed to observe the surface appearance and to identify the composition and phases of samples. The results showed that stearic acid SAMs had successfully been assembled on the surface of the samples, which had a good effect on corrosion resistance of materials and decreased the electric current density of SAM-sample 1% to that untreated sample; SAM inhibited the form of Mg(OH)₂ and had a good influence on bioactivities of pure magnesium.

Abstract: Transition metal phthalocyanine complexes have been applied in the dye-sensitized solar cells (DSSCs), owing to their high absorbance coefficient in red-light region, good thermodynamic stability and facile synthesis. Structures of carboxyphthalocyanine complexes containing zinc, cadmium and mercury were optimized using the B3LYP functional. The M-N distances (M = Zn, Cd and Hg) were calculated to be 2.03, 2.12 and 2.16 Å, respectively. On the basis of these geometries, the electronic spectra in ethanol were predicted at the time-dependent density functional theory (TD-DFT) level. It was shown that the variation of Zn→Cd→Hg changes the transition nature of lower-energy absorption, but slightly affects the excitation energies. In addition, the effects of basis sets (Lan2DZ and SDD), solvent-effect models (PCM and CPCM) and solvents (ethanol and methanol) on absorption spectra were discussed in detail.

Abstract: In the present study, the TiO₂-Ti compacts with Magneli phases Ti_nO_2n-1 were fabricated using the mixed powder of TiO₂ powder and addition Ti powder by spark plasma sintering (SPS). The composition and the crystal types of Magneli phases Ti_nO_2n-1 were examined. The results showed that various Magneli phases Ti_nO_2n-1 (single or multi Magneli phases) with the composition of Ti_1+yO_2-x were obtained. The Magneli phases Ti_nO_2n-1 were formed in the transformation from the mother phase rutile TiO₂ to TiO with increase in Ti addition fraction. In addition, the thermoelectric properties of the sintered compacts were also measured. The electrical resistivity of the sintered compacts decreased with increase in Ti addition fraction. The thermoelectric performance of the sintered compacts was improved by the formation of Magneli phases Ti_nO_2n-1 with the composition of Ti_1+yO_2-x.

Abstract: In this paper, experimental results and Monte Carlo simulation methods used to study irradiation damage of Electron-beam on high-power AlInGaP red LED. The electron beam range and distribution of energy loss in the LED chip are analyzed by CASINO program in detail, the high-power AlInGaP red LED is irradiated by different energy and dose of electron beam irradiation produced by the low energy electron beam irradiation equipment. We contrast the optical parameter of the irradiated LED with the unirradiated LED. The experimental result is analyzed and discussed by the mechanism of electron beam irradiation. The results show that: the luminous flux and power change of the irradiated and unirradiated LED are showed by dose-response. In process of irradiation, the elastic collision and ionization are occurred between the incident particles and atoms within the material, which cause defect in the internal structure of the AlInGaP material and form the color centers.