Advanced Materials Research Vol. 852

Abstract: This paper introduces the antibacterial white carbon black produced by the method of sol-gel,and explores the preparation conditions of antibacterial white carbon black copper and its antibacterial effect.By changing the concentration of metal ions , the reaction time, the speed in the process of preparation,the experiment results obtained optimum conditions is Cu²⁺ concentration of 0.05mol / L, reaction time 4h, speed 300r/min.

Abstract: Exfoliated graphite with large expanding volume (EV) was prepared by two-step intercalation, in which the mixture of nitric acid and phosphoric acid, and that of nitric acid and acetic acid were employed as intercalating agent step by step, and potassium permanganate was used as oxidant. Its preparation conditions were optimized by orthogonal experiment and parallel experiment, and its microstructure was analyzed by scanning electron microscope. The results show that the optimal preparation conditions for the first step intercalation are as follows: the mass-volume ratio of natural graphite (NG) to mixed acid is 1: 4, the volume ratio of nitric acid to phosphoric acid is 1: 2, the mass ratio of NG to potassium permanganate is 1: 0.2, and the reaction temperature is 20~30°C for 40~60 minutes. Those for the second step intercalation are as follows: the mass-volume ratio of acidized graphite (AG) to acetic acid is 1: 5, the mass-volume ratio of AG to nitric acid is 1: 1.5, the mass ratio of AG to potassium permanganate is 1: 0.15, and the reaction temperature is 20~30°C for 40~60 minutes, the EV is 450ml/g under the conditions listed above. The interlayers of graphite are fully opened and become a worm-like fluffy rope.

Abstract: Low grade ore iron with high phosphorus (LGIOWHP) is used as an adsorbent to remove phosphate from aqueous solution. The orthogonal experiment of L₁₆ (4⁵) was used to study the effects of experimental parameters on the phosphate removal rate. The important degree of the effects of parameters on the phosphate removal rate is as follows: initial pH > stirring speed > reaction time > reaction temperature > adsorbent dosage. The results show that the phosphate removal rate exceed 99% under the conditions of pH 5.6, temperature 65 °C, reaction time 75 min, particle size <0.147 mm, initial phosphate concentration 20 mg/L, adsorbent dosage 60g·L^-1 and stirring speed 200 r·min^-1. After phosphate removal reaction, the phosphate concentrations completely meet the requirement of national discharge standards of the second category pollution (GB 8978-1996 ).

Abstract: Finance and economics university practice teaching with teaching software platform based on network, the software platform to the large server to run the computer room environment, the server determines the success of practice teaching. Creep corrosion can lead to the production of lead-free process card function failure, cause the server can not operate normally. This paper analyzes on the creep corrosion the mechanism analysis, the conditions of. At the same time according to the proposed scheme, the high humidity and high sulfur environment of computer lab and practice prove, through the control room environment, to eliminate creep corrosion.

Abstract: Using poly (vinyl alcohol) (PVA) crosslinked with formaldehyde as matrix, starch or calcium hydrogen carbonate as the foaming agent and powdered activated carbon (AC) as the adsorptive constituent, porous PVA/AC composite was prepared by means of chemical crosslinking method. The adsorption behavior of simulated wastewater containing methyl orange dye on porous PVA/AC composite was studied. The experiment indicates that the optimal dosage of AC, sulphuric acid and formaldehyde (37% solution) are 5.0 g, 18 wt. % and 10 ml respectively at the condition of 10.0 g dosage of poly (vinyl alcohol), 95 ml distilled water and 10.0 g starch. It was found that starch was preferably incorporated into the PVA matrix in the form of an aqueous dispersion. In addition, the key factors of influence on water-absorbency including the amount of activated carbon and formaldehyde as well as the concentration of sulphuric acid have been discussed.

Abstract: The tungsten carbide reinforced Ni-based alloy composite coatings are prepared on the surface of 45 steel by plasma spray welding in back feeding method. The dissolution of Ni-based WC composite coatings was investigated. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy diffraction spectrum (EDS) were used to examine the microstructure and composition of the coatings. The results show that the WC particles are well-distributed in the matrix. The WC particles have a good wettability with Ni-based substrate. In the spraying process, the WC particles have been dissolved obviously, and the diffusion occurs between the WC particles and Ni-based substrate. The surface of the coatings has a microstructure consisting of WC, W2C, Fe7C3, Cr7C3 and γ- (Fe, Ni) solid solution. The hardness increases from the matrix to the surface of coatings and is up to 2311 HV.

Abstract: SiC_p/Al composites would produce a large thermal residual stresses field during cooling process. The thermal residual stress has a greater impact to the composites dimension stability and the accuracy of application. In this paper, the thermal residual stress in SiC_p/A356 composites was measured by X-ray diffraction and simulated by finite element method (FEM), the influence of particle shapes and cooling rates are considered, the stress field contour nephogram and stress-time curve during cooling was simulated. The studies present residual stress formed during cooling process because of the difference of thermal expansion coefficient (CTE) between SiC particle and aluminum alloy, the maximum stress distributes near the interface of matrix/SiC_p mainly. The stress-time curves are inconsistent under different cooling rates, the higher cooling rate, the more dramatic variety in stress.

Abstract: The reaction of copper 2,2-dichloroacetic acid, heterocyclic diimine (bipy) ligands under mildconditions affords one novel supramolecular complexes, [Cu (bipy)₂[[H₂₂ (bipy=2,2-bipyridine X=dichloroacetic acid). The compounds were constituted through hydrogen bonding and ππ interactions between the heterocyclic rings.

Abstract: The foundation backfill materials with pulverized coal ash and admixture gypsum fly ash were studied. The laboratory experiments were designed to determine its compaction characteristics, compressibility, intensity and bearing capacity of foundation with different mixture ratio. Dry density and strength property of fly ash with different water content were analysed. The result shows that the modulus, strength and foundation bearing capacity all have been greatly improved when gypsum was added into fly ash The proper mix proportion of the gypsum fly ash is very suitable for engineering application and this research provides a scientific reference for the similar projects.

Abstract: Ni/HCl-PANI composites were formed by depositing Ni films on HCl-doped polyaniline (HCl-PANI) substrates. A simple parallel resistor model is used to analyze the resistance-temperature (R-T) characteristic of the composite within 30-300 K. The theoretical analysis reveals that the composite exhibits a metal-semiconductor transition within a certain thickness of the Ni film or the HCl-PANI substrate. The composite shows a semiconducting behavior at temperatures over the transition temperature and a metallic conduction behavior at temperatures below the transition temperature. The transition temperature increases with increasing Ni film thickness whereas it decreases with increasing HCl-PANI substrate thickness. When the Ni film thickness exceeds its upper limit or the HCl-PANI substrate thickness is below its lower limit, the composite only shows the metallic R-T characteristic. When the HCl-PANI substrate thickness exceeds its upper limit, the composite only exhibits the semicoducting R-T characteristic.