Advanced Materials Research Vol. 465

Abstract: Au-TiO₂ composite photocatalysis material was fabricated by the photodeposition method. The SEM and TEM images demonstrate that Au-TiO₂ NPs are with inerratic geometry and their diameters are in the range of 10 nm to 20 nm. The UV-vis spectra shows the strong peaks in 200-400 nm and near 550 nm which are attributed to the characteristic absorption peak of TiO₂ and the strong surface-plasmon-resonance of Au NPs, respectively. Under visible light irradiation, the phenol degradation dynamics constant on Au-TiO₂ was 0.008 min-1 which was 4 times of that on Degussa P25. The effects of Au amount on the photocatalytic capability of Au-TiO₂ were also investigated.

Abstract: In this paper, the WC-5TiC-10 Co mixture mixed by WC2.96μm, (Ti, W)C 2.52μm and Co2.38μm and prepared by high-energy ball milling. The result shows: After 60h’s ball milling the powder began to reunite more and more as the time extended . The average grain size of powder is 50 nm after144h. After 1300°C~1400°C vacuum-sintering the hardness of the sample is 94.8 ~ 95.4HRA. 4.2 ~ 5.2 HRA higher than the traditional cemented carbides with the same composition. After 1400°C vacuum-sintering the compressive strength and flexural strength of cemented carbides is 2060 MPa and 1200 MPa. Slightly less than the traditional cemented carbides with the same composition.

Abstract: 12-tungstophosphoric acid was supported on amine-modified SBA-15 by impregnation. The structure and properties of the catalyst were characterized by FT-IR spectroscopy, X-ray diffraction, N2 adsorption-desorption, TEM,Raman spectra and NH3–TPD technology.the result confirmed the mesostructure for SBA-15 and the Keggin structure of the heteropolyanions was preserved. The tungstophosphoric acid can disperse in the pore of the support SBA-15/NH2, but the acidity of the catalyst reduced. The catalytic activities of the catalysts were evaluated for the esterification reaction of ethyl acetoacetate and ethylene glycol .and the catalysts supported on amine-modified SBA-15 show excellent reusability and selectivity.

Abstract: Polymethylmethacrylate (PMMA) modified poly(vinylidene fluoride) (PVDF) hollow fiber ultrafiltration membranes were prepared by wet spinning method using polyvinylpyrrolidone (PVP) as pore-foaming agent and mixture of dimethyl formamide (DMF)/methyl ethyl ketone (MEK) as solvent. The effects of PVDF, PMMA, PVP, and solvent ratios in the spinning solution on the permeation properties of the formed membranes were studied. The results showed that the performance of the membrane is the best with a pure water flux of 117 L/m2•h and rejection rate of 82% to bovine serum albumin (BSA), when the concentrations of PVDF, PMMA, PVP, DMF and MEK are 17, 3, 3, 60 and 17 wt%, respectively.

Abstract: Abstract: Ascorbic acid is important for human, but it will be oxidized fast when dissolved in water. However, in recent years, a major breakthrough has been achieved in the preparation of w/o/w multiple emulsions containing ascorbic acid (AA). And this study shows how to prepare and evaluate the stable gel-like multiple emulsions which can be easily used in personal care products. The concentration of ascorbic acid was analyzed by UV, and the viscosity of multiple emulsions thickened with xanthan was also appraised. The retention rate of ascorbic acid in multiple emulsions was 92.4% after 30 days preparation, and it was of significance for cosmetic use.

Abstract: A compact hydrophobic nanoparticles (HNPs) adsorption layer，which had miro- and nano- dual structural properties, can be built by adsorption of HNPs on core surfaces, and then the wettability of core surface can be change from hydrophilic into strong hydrophobic. Measurements validated that the maximum contact angle of HNPs adsorption surface was close to 150°. This method has a very good prospect for industrial application. The flow resistance can be significantly reduced when the water flow through the core micro-channel walls adsorbed HNPs. Core displacement experimental results show that the largest drag reduction rate can be up to 159%, and the average to 73.4%. The results have important significance to the studies of the HNPs drag reduction technology.

Abstract: First principle calculations have been performed to study the interface structure effect on physical properties of the Fe/BaTiO₃/Fe junction. It is identified that Fe on top of the TiO₂- terminated plane with two Fe atoms adsorbed on the two O top sites is the most stable interface. The interface structure is found to affect the ferroelectric behavior of BaTiO₃ layer. With BaO-terminated interface, BaTiO₃ shows larger Ti-O distance compared with TiO₂-teminated interface. In addition, there is a sizable difference in magnetic moments on interfacial atoms at the two interfaces.

Abstract: Colloidal packing by evaporation is a process that particles are packed by Stokes’ forces. As particles are far from each other, interactions among them are too weak to be taken into account and it’s the Stokes’ force on free particles that is in charge of packing. However, when they are close to some extent, the force is countered by particle interactions. Here, with the aid of force balance model, we demonstrate that the further packing is achieved by all drag forces of particles in the upstream.

Abstract: Abstract: In order to prepare natural anti-mosquito agent, the volatile oil was extracted from artemisia argyi by three-step of water extraction, steam distillation and organic solvent extraction. Three factors have been optimized. They were material/liquid ratio, distillation time and crushing particle size having influence on the extraction efficiency. The experimental results showed as: the optimum extraction process was that material/liquid ratio for 1:20, distillation time for 4 hours and crashing particle size for 40 meshes. At optimized extraction process condition, the extraction efficiency was 0.71%. Chemical constituents were determined by gas chromatography-mass spectrometry apparatus (GC-MS). They were mainly single terpenoids and its derivatives, including monocylic single terpenoids and 2-ring single terpenoids. Primary components were eucalyptol, camphor, camphene, borneol and so on. This provided good foundation for preparation of anti-mosquito and anti-insect agent.

Abstract: CdSe films have been prepared successfully by an ultrasonic chemical bath method, with CdCl2•2.5H2O and Na2SeSO3 as precursors, and trisodium citrate as complexing agent. The films were characterized by XRD, AFM, and UV-Vis. The results showed that the CdSe films were n-type semiconductor and had absorption in the visible region. The CdSe film electrode had higher electron transfer rate, which leads to a substantial improvement on the photocurrent. Optimal condition for preparing the CdSe thin films were as following: the ratio of Cd2+ to trisodium citrate was 1:1.5, the ratio of Cd2+ to Se2- was 2.5:1, the pH value was 10, the deposition time was 2.5h, and the annealing temperature was 350°C.