Abstract: Knitted fabrics have been widely used in different fields due to their high strength and elastic properties. However, these can only be used in limited applications due to poor liquid absorption owing to the large pore size of knitted fabrics. This study is focused on the structural characteristics of micro- and nano-filament warp as well as weft knitted fabrics. Nano-filament fabrics are manufactured by means of alkali treatment. Filament diameters are significantly reduced according to SEM micrographs. The decreased porosity of nano-filament fabrics indicates that nano-filament knitted fabrics possess excellent water absorptive capacity due to capillary action in the fabrics. Tensile behaviors of knitted fabrics in the wale and course directions are investigated as well.
Abstract: Recently, self-assembly synthesis of metal nano-particles has attracted great interest due to its unique size dependent properties. In this study, an easy synthesis would be developed to form Au nano-particles which are without toxicity. The Au particles could be applied in biological and biological toxicity experiments. Some phenomena could be discovered in this paper. First, the concentration ratio of Au and trisodium citrate would be adjusted to control the Au nano-particles size. And the particle size is limited because of the size dependent energy would be discovered in this paper. The minimum particle size is also found. The one phase liquid reduction method is easy and without toxicity, it is low-cost, high-throughput, and suitable to be applied in biological and biological toxicity studies.
Abstract: The regulation of stress concentration generated by the edge effect of shrink fit is studied in this paper. Firstly, experiment is designed with Latin hypercube (LH) method; then the maximum compound stress of the shrink fit is obtained by means of FEM; at last, the relationship among the maximum compound stress, shrink range, dimensional sizes of the shrink fit parts and material properties is fitted into a empirical formula via BP neural network. The formula is capable of offering good forecast to the maximum compound stress, and makes up the deficiencies of the design of shrink fit by using elastic mechanics (EM). At the end of this paper, the shrink fit of the drive axle housing is optimized with the empirical formula, and the maximum compound stress is abated greatly on the condition of ensuring the normal use of drive axle housing.
Abstract: The Cu-based friction materials with nano-AlN (n-AlN) and nano-graphite (n-C) were prepared by powder metallurgy technology, respectively. The microstructures and friction performance were studied through scanning electron microscope (SEM) and friction tester rig, respectively. The results indicate that the n-AlN and n-C particles can enhance the properties of Cu-based friction materials remarkably. Compared with the friction materials without any nanometer materials, the wear resistance of the friction materials with n-AlN and n-C has been improved by 25 % and 11 %, respectively. The heat resistance of the materials with n-AlN and n-C has been improved 18 % and 25 %, respectively. The n-AlN and n-C particles can reduce the abrasive wear and enhance the wear resistance of the Cu-based friction materials.
Abstract: Subscript textThe Co3O4 nanocubes were synthesized by hydrothermal process. The products are characterized in detail by multiform techniques: scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray analysis. The results show that the products are uniform nanocubes with an average crystallite size about 20-40 nm. Electrocatalytic property of the prepared Co3O4 nanocubes was characterized by linear sweep voltammetry. LSV results indicate that Co3O4 nanocubes exhibit a remarkable electrocatalytic activity for the H2O2 reduction.
Abstract: Poly(3-methylthiophene) (PMeT) was electrochemically synthesized on an ITO surface in the ionic liquid 1-butyl-3-metyllimidazolium hexafluorophosphate ([BMIM]PF6) by a potentiodynamic polymerization method. The poly(3-methylthiophene) was characterized by fourier-transform infrared spectroscopy (FT-IR) and energy-dispersive X-ray analysis(EDS). Scanning electron microscopy (SEM) was used to show the morphology of the PMeT film. Electrochemical properties of the prepared film were characterized by cyclic voltammetry.
Abstract: Formation of layered nanosheets and micro-spheres from a simple self-assembly and polycondensation of n-octadecylsilane (PODS) in water and toluene is demonstrated, respectively. The structure of the micro-spheres was characterized by Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD). According to the TEM images, it was firstly confirmed that the micro-spheres consist of stacks of bilayered polymerized n-octadecylsilane with head-to-head arrangements. The co-effects of water and solvent were proposed to control the octadecyltrichlsilane hydrolysis process and eventually the morphology of the micro-spheres. A micelle formation mechanism for the formation of the PODS micro-spheres under the co-effects of water and solvent were firstly proposed.
Abstract: Hot rolled high plastic stain ratio structural steel sheets was used to study the effect of cold reduction ratio and annealing process on the microstructures and mechanical properties. The results showed that the structural steel sheets was recrystallize finished after cold rolling follow different cold reduction ratio and batch annealing(annealing temperature 670°C and soaking time 5h) under experimental condition. When the cold reduction ratio was increased, the yield strength and tension strength increase, the elongation reduced followed different heating speed. The plastic strain ratio r value reached the maximum with cold reduction ratio of 50%, when the cold reduction ratio was increased, the r value was gradually reduced, However, the strain hardening exponent n value was gradually reduced. In the end, that suggested the optimal cold reduction ratio is 40% to 50%, and heating speed is 20°C/h, consequently that obtained good match of mechanical properties and punching property.
Abstract: α-Ni(OH)2 with hierarchical structures were synthesized via a simple route using Ni(NO3)2•6H2O and urea as the starting materials. The experimental results from XRD and FT-IR showed that the samples prepared by this method had the typical α-phase and the size of samples can be control by adjusting the reaction conditions. SEM images showed many uniform flowerlike or spherelike architectures with diameters of 4-6μm consisted of dozens of nanosheets. The effects of nickel sources on the phase and morphology of the prepared samples were studied, the nickel sources had an effect on both the crystallinity and size of the prepared samples.
Abstract: Commercial Cu0.62Zn0.38foil was subjected to surface mechanical attrition treatment (SMAT) processing. The original and SMAT Cu0.62Zn0.38 foils are thermally oxidized at 500°C under N2-5%O2 gas environments, at a pressure of 1 atm for 3 hours. The oxidized specimens were characterized with a scanning electron microscope, an X-ray diffractometer. It is found that nanosheets are easily formed on the SMAT specimen surface. The favorable formation of nanosheets relates to twin–matrix lamellae structure.