Abstract: Biological multilayer films of redox polymer and horseradish peroxidase (HRP) were successfully assembled on a screen-printed carbon electrode using layer-by-layer (LBL) assembled method based on the electrostatic interaction. The screen-printed carbon electrode surface was modified by the positively charged redox polymer, and the negatively charged HRP by LBL method.
Abstract: Cu-1.37Cr alloy powders were prepared by gas atomization process, and the cooling rates of alloy powders were calculated through the convection heat transfer principle. The morphology, distribution of alloy elements and microstructure of Cu-1.37Cr alloy powders were characterized by X-ray diffractometer and Scanning Electron Microscope (SEM).The results show that the cooling rate increases from 9.75×103 to 1.08×105 K/s as grain size decreases from 150 to 45µm. The morphology of alloy powders are spherical or similar spherical shape along with smooth surfaces. The grains have uniform size, and Cr particles are uniformly distributed in Cu matrix. With decrease of particle sizes, the diffraction angle shifts into small angle, suggesting that the larger solubility of Cr in Cu phase.
Abstract: Nanofluids are a new class of heat transfer fluids and offer an important advantage on conventional heat transfer fluids. The nanometer-sized metallic and non-metallic solid particles or tubes are dispersed in base heat transfer fluids such as water, engineering oil and emulsion. It is a interdisciplinary field between nanoscience, nanotechnology, and thermal engineering. The nanofluids study work attracts a lot of interest from the worldwide researchers because of their fascinating thermal characteristics and potential applications in microelectronics, transportation and biomedical fields. Many important theoretical and experimental study works on convective heat transfer appeared in literature. The purpose of this article is to study theoretical and experimental findings on the enhancement of the convection heat transfer with nanofluids and analyze the key factors of thermal conductivity and convective heat transfer enhancement with nanofluids.
Abstract: Fast-growing plant wood, Micheliamacclurel wood, was modified by formation of wood-polymer composite to improve its decay resistance. Two functional monomers, glycidyl methacrylate and ethylene glycol dimethacrylate, added with a few Azo-bis-isobutryonitrile as initiator, and maleic anhydride as catalyst, were first impregnated into wood cell lumen under a vacuum-pressure condition, and then in-situ polymerized into copolymers through a catalyst-thermal treatment. The decay resistances of untreated wood and wood-polymer composites were assessed by weight loss and compared by SEM observations. SEM and FTIR analysis indicated that the in-situ polymerized copolymers fully filled up wood cell lumen and also grafted onto wood cell walls, resulting in the blockage of passages for microorganisms and moisture to wood cell walls. Thus, the decay resistance of the wood-polymer composite against brown rot fungus and white rot fungus in terms of weight loss achieved 1.04%~1.33%, improved 95.10%~95.35% than those of untreated Micheliamacclurel wood; and also higher than that of boron-treated wood. The SEM observations presented the remarkable improvement of decay resistance of wood after such treatment, which effectively protected wood from degradation by fungi.
Abstract: In this study, a new composite was prepared for aniline adsorption by melt blending with EPDM as the matrix and natural zeolite was modified by microwave as the filler. The properties and some influential factors of composite for adsorption of aniline in the solutions were experimentally investigated, such as composite dosage, adsorption time and pH values. The results showed that in the case of the initial concentration of the aniline wastewater was 50mg/L, when the use level of composite was 1 g, pH value was 1, and the oscillating adsorption time was 2 h, the removal rate could be up to 92%.
Abstract: To obtain high properties of laser cladding layer, and to expand the service life of the mold, the laser cladding layer with Ni-WC and SiC on the surface of H13 steel made by using a laser. Then the cross-section and surface morphologies of the coatings and wear tracks were observed with a JSM-5610 type scanning microscope. The friction and properties were examined under dry sliding conditions using a WTM-1E type ball-on-disc machine. The wear mechanisms are discussed as well. The results show that the composite coating is very compact and good blinding with the substrate after laser remelting, and the wear mass loss of the composite coating reduced to about 1/4 of the matrix material.
Abstract: The γ-LiAlO2:Co 3+ ceramics were successfully fabricated by using multi-mode cavity microwave furnace, and the sample’s infrared absorption and photoluminescence spectra were measured at room temperature. There are nine bands in the range of 1300-48000 cm-1. Using the crystal-field theory and introducing the average covalent factor model, we calculated the energy splittings of Co3+ ions in γ-LiAlO2. These bands were firstly explained and assigned. These calculation results are in good agreement with the optical experiment data.
Abstract: EPS light-aggregate concrete is a new kind of light aggregate concrete and is paid more attention by engineers in the field for superior thermal technology performance and prominent economic benefits, in which the Nano-SiO2 can not only fill the lacuna of concrete to improve the performance of concrete but also can improve the mechanics performance and the strength of concrete obviously. The compressive strength and flexural strength of EPS light-aggregate concrete in 3d and 28d were the maximum with 5% Nano-SiO2 in concrete. It is very significant to research the effect of nano-materials on EPS light-aggregate concrete performance, and its application in construction industry will bring great value to practical engineering and social economic benefits to our society.
Abstract: Some experiments found that the low-frequncy sound absorption performance can be improved by inserting MPP into the multi-layer porous materials, but the theory modeling of this MPP-multi-layer porous combined absorber is too difficult to provide the guidance. Therefore, a new method is proposed in this paper, according to Atalla’s theory, the MPP can be treated as a rigid porous layer in this composite absorber, then the acoustic software (such as VA One) usually for dealing with multi-layer porous absorber can be chosen to its optimal design. Based on this method, a two-layer porous absorber is designed using the Foam Module of VA One, and the influence of different insert location of MPP in the two-layer porous absorber is analyzed, which shows the existence of optimum location. Moreover, the sound absorption of different MPP structure at the optimum location is also discussed which shows inserting the wider-band MPP structure is better.
Abstract: Electrolytically deposited palladium on polypyrrole film, which is electropolymerized using potentiostatic method, covered foam nickel electrode as a support was used as cathode for the electrocatalytic hydrodechlorination of 2, 4-dichlorophenol in aqueous solution. It is well known that the morphologies of polypyrrole films have dramatic influences on the dispersion of metals and the performance of the composite electrode. The influence of applied potential, temperature and polymerization time on the morphology of the films was studied by scanning electron microscopy (SEM). The fundamental electrocatalytic hydrodechlorination (ECH) results indicated that the electrocatalytic activity of Pd loaded polypyrrole foam nickel electrode is excellent for dechlorination of 2,4-dichlorophenol. The present study shows a promising choice of this kind of composite electrode for ECH.