Advanced Materials Research Vols. 311-313

Abstract: The nanocrystalline Cu-5wt.%Cr alloy powders were prepared by mechanical alloying. The structural changes were characterized by X-ray diffraction (XRD) technique. A thermodynamic analysis was carried out to predict the change in the solubility limit of this system. It was found that the energy resulting from the MA process is sufficient to increase the solid solubility of immiscible Cr-Cu system. The solid solubility may be extended up to 5 wt.% Cr in Cu after 20 h milling. The formation of the supersaturated solid solution leads to the decrease of Cu lattice parameter. However, it decomposes with the further increase of the milling time, which leads to the increase of Cu lattice parameter.

Abstract: Abstract. Foam, as a mobility control agent in enhanced oil recovery, is becoming more and more attractive. However, this method may be inefficient when water channeling appears in the reservoir due to its heterogeneity. Therefore, it is reasonable to block its flow through preferential channels by an enhanced foam system. A novel foam system is developed by the combination of general two phase foam system with solid particles to improve its performance for deep conformance control in reservoirs. This new foam system involves gas, liquid and particles. Firstly, micro-sphere shape and morphological distribution of particles have been observed through the microscope. Destruction mechanism and stability of multi-phase foam were analyzed in theory. In addition, the concentration of polymer and solid micro-sphere used as the foam agent were determined by orthogonal experiments. Next, micro-sphere displacement experiment shows that it can not only block throats but also migrate through throats by deformation, which can be represented by the pressure curves. Multi-phase foam system presents a similar pressure fluctuation with micro-sphere flooding. Finally, the parallel core experiments were conducted to investigate pressure distribution of two phase foam and multi-phase foam system in porous media respectively. The results show that multi-phase foam can effectively improve the profile control ability and it is adaptable for deep conformance in reservoir.

Abstract: Terahertz spectroscopy (THz) is a brand-new radiation source with many unique advantages. It owns many potential applications in all area. An experiment was carried out on soil heavy metal detection using THz in Jun., 2010 at Oklahoma State University. Two types of sample holders (1.5mm thickness and 3 mm thickness) were designed based on specific requirements and applications in this paper. The optical material, size, thickness of the sample, thickness of the side-wall, property of samples for holding, adhesive materials, cost were discussed in detail; then, an integrated description were given and a 3-D model was established. Real holders were manufactured based on the former design and their THz characteristics were measured. At last, the holders were used in the current soil heavy metal detection experiment. The results showed that, the designed holders showed low absorption of THz and low reflection. Two thickness samples holders all performed well in the experiments, however, for the soil measurement, the sample information could not be completely collected before echo wave came. The 1.5mm thickness holder was selected in our experiment. The designed sample holders are feasible and this research provides a good solution for the difficulties we met in our experiment.

Abstract: Zn-doped Bi-Mo complex metal oxide photocatalysts were prepared via hydrothermal process. The prepared samples were characterized by X-ray powder diffraction and UV-vis diffuse reflectance spectroscopy. The results display that Zn doping can not alter the crystal form of the complex metal oxide and the band gap of the samples are all about 2.56 eV. The photocatalytic activity of the samples for the decomposition of Rhodamine B under visible light irradiation shows that the concentration of Zn2+ has great effect on the photocatalytic activity and the best photocatalytic activity is obtained by the sample with 0.6% Zn doping amount.

Abstract: Composite electrodes based on vertically aligned multi-walled carbon nanotubes (MWCNTs) coated with vanadium oxide (V₂O₅) have used in supercapacitors. The vanadium (V) oxide (V₂O₅) cathodically deposited on titanium collector in vanadium oxide solution. The novel supercapacitor performed by V₂O₅/MWCNTs/Ti electrode in 1.0 M HCl aqueous solution can reach a specific capacitance of 713.3 F/g at 10 mV/s, which is larger than that of MWCNTs/Ti. To characterize the V₂O₅/MWCNTs/Ti composite electrode, cyclic voltammetry and galvanostatic charge-discharge method were executed, and the morphology of the composite electrode was examined by scanning electron microscope. This nanocomposite electrode greatly enhanced the utilization efficiency of supercapacitor electrode material, low material cost and provided both high capacitance and power density.

Abstract: The optimal parameters of the chitosan-coated ferrofluid under two patterns of irradiation were investigated in this study. The quality characteristics were set both to the SAR (specific absorption rate, W/g) and the particle size (nm). The control factors were chosen as the gamma irradiation dose (Gy), the quantities of chitosan (g), and the molar ratio of Fe ³⁺ to Fe²⁺. It shows that SAR is a better choice for determining the quality characteristic. The quantities of chitosan have a less significant impact on SAR. The optimal condition for the Fe³⁺ /Fe²⁺ ratio was found to be between 2.0 to 2.5 when synthesizing the magnetite Fe₃O₄ cores. High dose (100 k Gy in this study) of gamma ray irradiation given only to the solid chitosan will have a significantly positive effect on SAR of the chitosan-coated ferrofluid for hyperthermia. However, high dose irradiation of the chitosan-coated ferrofluid tends to destroy the chitosan-magnetite cores bonds.

Abstract: Catalytic combustion of toluene on Cu-Mn complex oxides was investigated. The catalysts were prepared by urea-based hydrothermal method and characterized by XRD and SEM. It was found that both the decrease of the Cu/Mn molar ratio and the increase of reaction time contributed to improving catalytic activity for toluene combustion. The temperature for 99% conversion of toluene (T₉₉) was lowered to 210°C. The main crystalline phases of Cu-Mn complex oxides were CuO and Cu_0.45Mn_0.55O₂. It was showed that the existence and high dispersion of Cu-Mn complex oxides were related to the catalytic combustion activity.

Abstract: In this study, a competitive assay format using superparamagnetic nanoparticle-based lateral flow immunoassay (LFIA) was developed for rapid, quantitative detection of shellfish major allergen tropomyosin (Tm). Sartorius CN140 nitrocellulose membrane and 0.05mg/mL Tm immobilized in the test line (T line) were optimized in order to improve the performance of the LFIA system. Calibration curves for Tm under PBS-T diluents and carp muscle extraction diluents were established. Limit of detection (LOD) for Tm calibrated by carp muscle matrix was 12.4ng/mL with a work range of 0.01 to 20μg/mL. According to magnetic signals change with the time of sample flowing on the strip, the qualitative time of the LFIA was about 10min, while the quantitative time of the LFIA was about 25min. 30 food species were detected separately by the LFIA and Western blot method to evaluate the specificity of the LFIA. Overall relative agreement of the two methods was 96.7% (29/30). Moreover, intra- and inter-assay precisions of the LFIA for Tm detection were <10.20% and <12.34%, respectively. The average recovery range in different food matrices was 80.3~111.8%, within a reasonable range. Our data confirmed that the superparamagnetic nanoparticle-based LFIA method developed in this study is rapid, simple, high specificity and capable of quantitative test. Consequently, the LFIA has the potential application in the field of point-of-care test of shellfish major allergen Tm.

Abstract: Magnesium aluminate (MgAl₂O₄) spinel nanoparticles were prepared by non-hydrolytic sol-gel method using anhydrous alcohols as oxygen donor. XRD and FTIR were used to characterise the effect of anhydrous alcohols on synthesis of MgAl₂O₄ spinel nanoparticles.The results showed that when the oxygen donor used in stoichiometric ratio for synthesizing MgAl₂O₄, anhydrous ethanol was the more effective oxygen donor than anhydrous isopropanol. But there was no remarkable effect on synthesis of MgAl₂O₄ spinel when the amount of anhydrous ethanol exceeded the stoichiometric ratio. The mean particle size MgAl₂O₄ spinel nanoparticles was in the range of 40 to 50 nm.

Abstract: Electrospinning is an effective and versatile technology to fabricate ultrafine nanofiber,however further development is urgently limited due to the low uniformity distribution and unpredictable feature of the fiber deposited. For that sake, experiment has been done and analyzed to address these problems. Relation between process physics-Taylor cone and fiber diameter characters has been discovered. Furthermore, the feature parameters of the Taylor cone are extracted effectively by CCD detection and image processing. The above experiments results and processing data is analysis and examed by the steady jet theory. This paper offers significant theoretical guidance and technical support to the online control of electrospinning fiber diameter.