Papers by Keyword: Property Analysis

Abstract: Polycarboxylate was synthesized by using polyethylene glycol monomethyl ether methyl-acrylate (PEG16), methylacrylamide sodium (MAS), methacrylic acid (MAA), methyl acrylate (MA), acryl amide (AM), and sodium persulfate (SPS) and evaluated as a superplasticizer for cement particles. The formulation of the superplasticizer: n (PEG16): n (MAS): n (MAA): n (MA): n (AM) =10:18:20:37:20, and the content of the SPS was 1.2wt% of all the monomers and optimized reaction conditions (80°C, 6h) were obtained via orthogonal test and single factor experiments. The water reducing effect of the synthesized copolymers was studied in terms of reaction temperature, reaction time and PEG side chain length. In this study, flow test of cement paste measurements were performed to compare the molecular weight effect on fluidity of the copolymers. It was observed that the reaction temperature had a noticeable effect on the molecular weight of the PEG-grafted samples thus causing a significant effect on fluidity. The polycarboxylate synthesized at about 80°C has given the highest fluidity result. In addition, the reaction time 6~7 hrs was identified for the best. Furthermore, copolymers with mPEG side chains with a degree of 16 gave the highest fluidity and viscosity average molecular weight value. The initial fluidity of the cement paste containing the prepared superplasticizer (1wt%, w(water)/w(cement)=(0.29)) was 316 mm.

Abstract: Ants System is one bionic algorithm developed in recent years, lacking rigorous theoretical instructions. In this paper, studies on the properties of Ants System are made and several parameters concerned, include: ant initial number m、transfer control parameter q0、importance of visibility β and stigmergy decay parameter , are analyzed, which is of reference significance.

Abstract: The influences of ZnO photoanode structure on the properties of ZnO dye-sensitized solar cell were studied in this paper. Four kinds of ZnO photoanode films prepared from ZnO nanopowders, nanorods, nanosheets and aggregates were investigated. Their photovoltaic parameters were discussed and compared. ZnO cell consisted of ZnO aggregates had optimal properties, photoelectric conversion efficiency, open circuit voltage, short-circuit current and the fill factor of ZnO aggregates cells were 2.15%, 0.64V, 6.47mA•cm-2 and 0.52, respectively.

Abstract: Based on the background that large amount of iron ore tailings are stockpiled in China, the utilization of iron ore tailings to prepare sintering brick was studied. The main objective of this paper was to investigate the influence of sintering temperature on sintering bricks from iron ore tailings, in the presence of clay, coal refuses and bentonite. Sintering bricks were prepared at different temperature with 40 wt% iron ore tailings. Drying was investigated as well as the loss on ignition, bulk density and compressive strength of the specimens. Their mechanical and microstructure properties were also investigated by radioactivity, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that compressive strengths of the specimens produced were higher than that required by the standards MU20 of GB5101-2003, up to 128.0Mpa at 1100°C corresponding to its higher bulk density completely.

Abstract: Oxidized MWNTs were obtained by the oxidization in the mixture of concentrated HNO3 and H2SO4. Amino-functionalized MWNTs were obtained by the oxidized MWNTs reacting with aliphatic amines. The structure and properties of functionalized MWNTs were characterized by FT-IR, TGA, XRD and nanoparticle size analyzer.

Abstract: Five groups of polyacrylate dispersion are prepared with emulsion polymerization technique. Methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA) and styrene (St) are employed as basic polymerizing monomers; acrylic acid (AA) and glycidyl methacrylate (GMA) as reactive monomers; sodium dodecylsulfate (SDS), composite fatty alcohol ether polyethylene oxide (composite AEO) as emulsifier and ammonium persulfate (APS) as initiator. The polymerizing monomers and their charge ratio, pH of pre-emulsions and product emulsions as well as the dosage of ecological cross linker GMA are changed for their effects on the reaction conversion rate, gelatinization rate and staining resistance, yellowing resistance and water tolerance of samples. The studies show that the pH value of pre-emulsion and product emulsion as well as GMA content act on remarkable effects on the application properties of the ecological polyacrylate pigment binder.

Abstract: The extruded microstructure and properties of Mg-2.7Nd-1.2Gd-0.4Zn-0.3Zr alloy by squeeze casting were investigated. After aging process (T5), the dislocation density was enhanced and the dislocation interaction was increased; the factors of grain refinement, RE phases redistribution, the increment of dislocations and the interaction between dislocations and precipitate phases were contributed to the strength increase after hot extrusion and aging treatment, the fracture mode of the hot-extruded alloy was the fracture of the secondary phases and the trans-grain fracture.

Abstract: Taking L-Lysine Diisocyanate (LDI) as hard segments, poly-ε-caprolactone diol (PCL) as soft segments, a kind of nontoxic and biodegradable waterborne polyurethanes were synthesized using two-step polymerization. And then the effects of isocyanate/macroglycol molar ratio(NCO/OH, R value), the 1,4-butylene glycol (BDO) content and prepolymerization temperature on the properties of waterborne polyurethanes were investigated. The experimental results showed that when R value is 1.5, the BDO content used is 4% and the reaction temperature is 80°C, the products prepared were best in application. The mechanical property tests showed that it has good mechanical properties, tensile strength is up to 46.5MPa and the loss amounts of the hydrolytic degradation after 80 days is 42%. The waterborne polyurethanes prepared have excellent biodegradability, which can be widely used as a biological medical material.

Abstract: Amide surfactants have modified structures with lipophilic groups connecting hydrophilic groups through amido bond. The preparation of three families of amide surfactants including long chain N-acyl sarcosinates, amidopropyl dimethyl hydroxypropyl sulfobetaines and lauryl amidopropyl trimethyl ammoniums were discussed. The study of the surface activity of these compounds by measuring the equilibrium surface tensions of their dilute aqueous solutions were described. The minimum surface tension and the critical micelle concentration values of these compounds are given.

Abstract: his paper studies the feasibility of preparation high strength fired bricks from iron tailings with addition of clay and coal gangue. The results indicated that the optimum conditions were found to be that the hematite tailings content were 35%–50%; the firing temperature was 1000 °C. Under these conditions, the mechanical strength, the water absorption and the bulk density of the fired bricks were 21.17–26.14 MPa, 14.55–15.47% and 1.648–1.629g/cm³, respectively, these were well conformed to standards MU20 of Chinese Fired Common Bricks Standard (GB/T5101-2003).The phase composition and microstructure of the fired specimen were characterized by XRD and SEM. The results showed that the major crystalline phases present in fired brick were quartz, albite, amphibole, hematite and muscovite, and glass phase encapsulated and cement the crystalline phases forming strong entirety which promoted the strength of bricks.