Advanced Materials Research Vols. 850-851

Abstract: Chitosan has good biocompatibility and physiological activity, tourmaline possesses characteristics of generation of anion, reduction of water molecular beam and emission of far infrared radiation, so the two composite materials will hopefully possesses the two excellent properties, thus show good application prospect in the biomedical and cosmetic field. Experiment utilized chitosan as wrapped base material, adopt method of suspension solution compound precipitation to manufacture chitosan/tourmaline compound powder, using XRD, SEM, IR and other means to represent powders prepared, and the experimental results show that the synthetic compound powder with irregular granular, chitosan wrapped tourmaline well, the composite of tourmaline and chitosan is physical composite, with the increment of tourmaline , the degree of crystallization of chitosan in compound powder weaken, the composite powder has good absorptive and preservative liquid ability.

Abstract: A novel chitosan-based composite nanofibers which was composited poly (vinylpyrrolidone) (PVP) and poly (vinylalcohol) (PVA) was prepared by electrospinning, and the spinnability and morphology of CS-based composite nanofibers were investigated. The result of SEM showed that with the introduction of PVP to composite fibers the spinnability of the system was improved. And the CS/PVA/PVP composite fibers displayed mean diameter of 71 nm and narrower diameter distribution than CS/PVA composite fibers. IR demonstrated that there were intermolecular hydrogen bonds in CS/PVA/PVP fibers. XRD showed that the crystalline microstructure of the fibers was not well developed.

Abstract: Scanning electron microscope (SEM), X-ray diffraction (XRD), VSP electrochemical workstation and friction and wear tester equipment are applied for comparing the effects on organizations and properties of micro-arc oxidation fabricated on a piece of aluminum alloy sample with additives of La (NO3)3 or Ce (SO4)2. The results revealed that both coatings with these two different additives are consisted of α-Al2O3 and γ-Al2O3, but the peaks of main phases are evident with La (NO3)3. Compared the two different coatings, it could be found that less micro-cracks can be observed from the coating with La (NO3)3 additive. Beside this, aperture in this coating is also smaller and corrosion resistance and wear resistance are much better.

Abstract: In this paper, Samples are subjected to tensile test, metallographic microscope observation, scanning electron microscopy (SEM) analysis for exploring the effect of different retrogression and re-aging (RRA) treatments on the organization and properties of casting aluminum alloy. Results show that after aging at 170°C for 10h ,then regression at 230°C for 10min ,finally aging at 170°C for 10h, tensile strength of the sample is 430.19MPa, elongation is 6.18%, compared with the sample aged at 170°C for 10h (The tensile strength was 426.78MPa, elongation was 3.68%). It demonstrated that through the RRA process, strength of sample can effectively maintain at a similar high level as the samples processed single-stage aging. Meanwhile, the elongation of the sample increase nearly 67.9%. The microstructure characterizations indicate that RRA treatment induced the formation and growth of rod-like T phase, and the T phase homogeneously dispersed in the matrix of alloy. This process is proposed to be the major reason for the improvement of ductility.

Abstract: The effects of support modification on cobalt based catalysts in Fischer-Tropsch synthesis were investigated. Part of silica support was modified with ammonia solution and the other part not. The Co/SiO₂ catalyst with the support surface modified by ammonia solution showed larger particle size, strong Co-Si interaction, higher activity and selectivity in Fischer-Tropsch synthesis. It could be concluded that the support acidity can be controlled thus affected the reaction property of the catalysts in Fischer-Tropsch synthesis.

Abstract: In this study, Porphyrin functionalized graphene is used to electrochemically detect dimethoate. It is found that synergistic effects from the good adsorptive properties of porphyrin and the large electroactive surface area and fast charge transfer of graphene contribute to the sensitive detection. Under the optimum experimental conditions, the oxidation current of dimethoate was proportional to its concentration from 1.0×10^-6 to 2.0×10^-4 M .The detection limit was estimated to be 8.0×10^-7 M (S/N = 3).

Abstract: TiO₂ nanosheets have been successfully synthesized via a simple sol-gel process. These nanostructures were characterized by transmission electron microscopy (TEM) and x-ray energy dispersive spectrometer (EDS). The sheet-shaped single-crystalline nanostructures are pure rutile-phase structure, with landscape dimension of 10-45 nm. EDS investigation confirms that the TiO₂ nanosheets are only composed of Ti and O, and the atomic ration of Ti and O is close to 1:2. High photocatalytic activity might be expected for those TiO₂ nanosheets due to their large surface area.

Abstract: The thermal properties of calcium oxalate were studied by means of TG analyzer. The factors such as heating rate, filling amounts of specimens and filling atmosphere etc., which may affect thermo gravimetric (TG) curves in TG analysis test were investigated. The results showed that, with the improving of heating rate, filling amounts of specimens and close packing, the starting reaction temperature was postponed more obviously and the width of reaction temperature range rises. The flow of the nitrogen gas enhanced heat transmission, caused the starting reaction temperature to shift to the low temperature zone, and it could also affect the response course. But the factors above didnt obviously influence the weightlessness of specimens.

Abstract: The polyethylene glycol is a kind of phase change energy storage material with small thermal hysteresis effect, the phase change enthalpy and phase transition temperature varies with its different molecular weight. This article summarizes polyethylene glycol as research progress of phase change energy storage material, which mainly discusses the preparation methods and outlook about form-stable phase change materials.

Abstract: A new TiO₂-nanoSiO₂ hybrid film is prepared through adding the nanosized SiO₂ into the TiO₂. A more environmental and simpler method is found to prepare CdSe quantum dots (QDs) sensitized TiO₂nanoSiO₂ hybrid films for the quantum dots-sensitized solar cells (QDSSCs) application. The prepared colloidal CdSe QDs (~2.6nm) was linked to the TiO₂-nanoSiO₂ hybrid film using 3-mercaptopropionic acid (3-MPA) as a linker molecule slowly with drop and drop. The power conversion efficiency of 1.33% was achieved using the sensitization photo-electrode prepared by using TiO₂nanoSiO₂ hybrid film modified with CdSe (TiO₂-nanoSiO₂/CdSe) under the illumination of one sun.