Advanced Materials Research Vols. 287-290

Abstract: Due to the easy cracking of shotcrete, shrinkage-compensating shotcrete is researched and its micro-structure and strength properties are analyzed. Firstly, cement slurry is made by CSA, accelerating agent and two different cements. When hydrated 3 days and 28 days , hydration products of cement slurry are analyzed by SEM and XRD in feature, crystal characteristics and mineral compositions. The compatibility of the two different cements and admixtures is studied in apparent characteristics, and the fact that Portland cement is more suitable for making shrinkage-compensating shotcrete is obtained. Then, mechanical properties of concrete which consists of Portland cement, expansive agent and steel fiber are did to analyze the influence of strength characteristics caused by mix amount of expansive agent and steel fiber. The results show that the compression strength and tensile strength of concrete improve with the increasing mix of steel fiber. Incorporation of the expansive agent is greater impact on concrete strength, when mix amount of expansive agent is 8%, strength properties are the best. When mix amount of steel fiber is 1.0% and expansive agent is 8%, the effect of cooperative enhancement is the best.

Abstract: on the analysis of the ageing kinetics model, ageing kinetics equation has been established on the basis of complex modulus. Rheological properties test have been carried out on SBS modified asphalt and base asphalt. The results demonstrate that when asphalt material in ageing process, the hypothesis that complex modulus is inversely proportional to the concentration of reactant assumptions of ageing reaction is established, on the basis of which, ageing kinetics constant has been obtained. Ageing kinetics equation has been validated by using measured data, it shows that, SBS modified asphalt owns higher reaction activation energy, a good anti-ageing property as well, that the measured data can keep accordance with calculated data, which demonstrates ageing kinetics equation is established reasonably on the basis of complex modulus. The equation can well describe rheological state changes of asphalt in ageing process.

Abstract: Nip type flexible a-Si solar cells for application in building integrated photovoltaics (BIPV) were deposited by plasma enhanced chemical vapor deposition (PECVD) method. In order to improve the efficiency and stability of the device, p-type microcrystalline silicon (μc-Si:H) film was used as the window layers. H plasma treatment was applied on the p/i interface and nucleation layer was introduced to enhance the deposition of p-type μc-Si:H film on the surface of a-Si:H. Results suggest that with the application of H plasma treatment and the nucleation layer introduction, high quality p-type μc-Si:H film and high efficiency flexible solar cells were obtained.

Abstract: In order to estimate late strength of high performance concrete on based of early strength, so which can realize shorting time cycle of proportion design and proportion verification of high performance concrete, and can realize controlling node of key working procedure for the structure of high performance concrete in the course of construction. The paper obtained early strength and established relationship between early compressive strength and late compressive strength of high performance concrete on based of method of microwave promoting curdle. Getting early strength can realize to predict compressive strength through applying in the method of microwave promoting curdle.

Abstract: The means of current experimental study on expansive soil dilatancy primarily count on triaxial apparatus and compression apparatus. The narrative revealed in the article is in relation with expansive soil trial by means of CBR test, with outcome linked to regulation among swelling amount rating with time, initial moisture content, and dry density, which leads to high value associated with implication for predicting expansive soil deformation with moisture.

Abstract: Compression-tension test and direct shear test are used to evaluate the shear behavior of remolded loess under different water content and different dry weight density. Through massive analysis of test data, it is found that the valves of c and φ determined by compression-tension test can be used to characterize the shear strength index of soil.

Abstract: Compound binding material was prepared by the alkali activation of metakaolin and ground granulated blast furnace slag. Hydration product components, microstructure and mechanical properties of the hardened paste were investigated by IR, XRD, SEM, MIP, and compressive strength measurement. Results indicated that hydration products included C-S-H and geopolymer, and both of them were amorphous although there were differences in their structure and morphology. When the dosage of slag was less than 50%, the compressive strength of hardened paste increased as the dosage increased, which was mainly because C-S-H produced by the reaction of GGBFS and alkali filled void in geopolymer phase, and part of unreacted slag particles acting as microaggregate to prevent from extension of microcrack in the hardened paste, so the porosity of hardened paste decreased and compressive strength increased.

Abstract: In order to overcome the limitation of Li-ion batteries at low temperature, series of electrolytes are prepared. Specially，FEC is chose to work as electrolyte solvent to enhance its poor performance. Electrolytes are composed of EC, PC, EMC and FEC, while VC is added as additive. Electrolytes with different ratio are examined, then the electrolyte with the best conductivity is studied in detail. Its characters are evaluated by CV, EIS and charge/discharge tests et al. The discharge curves of LiCo_1/3Ni_1/3Mn_1/3O₂/Li show that battery with this FEC-based electrolyte at 233K could yield 51% of room temperature capacity. Most obviously, MCMB/Li half cell with this electrolyte could fill 91% of its normal capacity at 233K while batteries barely charge any with traditional electrolyte（LiPF6/EC+DMC(1:1 in volume)）. This nice charge behavior won’t emerge unless the conductivity could basically meet the demand at 233K. The property of FEC-based electrolyte outweighs commercialized electrolyte as this article confirms.

Abstract: Nanostructured elements, including: manganese-molybdenum (Mn-Mo) oxide, manganese-molybdenum-tungsten (Mn-Mo-W) oxide, manganese-molybdenum-iron (Mn-Mo-Fe) oxide, manganese-molybdenum-cobalt (Mn-Mo-Co) oxide, manganese-vanadium-tungsten (Mn-V-W) oxide, manganese-vanadium-iron (Mn-V-Fe) oxide and manganese-iron (Mn-Fe) oxide, have been anodically deposited onto titanium substrates by employing an iridium dioxide interlayer (Ti/IrO₂ anode). The electrochemical characteristics of the resultant oxide deposits have been investigated by cyclic voltammetry (CV) in an aqueous 0.1 M Na₂SO₄ solution. The voltammetric behaviors of the oxide deposits observed are significantly influenced by the doped elements. Molybdenum doping is found to be advantageous at improving the capacitance characteristics of anodically deposited manganese oxide. Comparatively, iron and vanadium doping are found to be unfavorable. The structure and crystallinity of these deposits have been identified by X-ray diffraction (XRD). The surface morphologies of these oxides were acquired from field emission scanning electron microscopes (FESEM). The high values of electrical parameters for the doped deposits are attributed to the net-like and sponge-like nanostructure, and low crystallinity of the doped manganese oxides. The deposit of Mn-Mo oxides exhibits an excellent capacitive-like behavior, possessing the maximum specific capacitance of 810 F g^-1 at a CV scan rate of 5 mV s^-1 in aqueous 0.1 M Na₂SO₄ solution.

Abstract: The LiMnPO₄ cathode materials for lithium-ion batteries were synthesized by microwave processing combined with precursor synthesized by sol-gel method. The structure, surface morphology and charge-discharge performance of LiMnPO₄ were characterized by X-ray diffractometry, scanning electron microscopy and electrochemical measurement respectively, and the effect of pH, microwave power and heating time on the electrochemistry properties were explored. The results show that when the pH value of the solution was kept at 9, pure phase LiMnPO₄ cathode material could be synthesized by microwave heating for 20 min under 480W, with a initial discharge capacity of 57.3mAh/g at 0.1C and a stable cycle ability.