Abstract: The structure of austenitic steel before and after 25% of total number of cycles of low cycle fatigue tests conducted at room temperature is studied using TEM. It is shown that the cyclic deformation of the steel proceeds heterogeneously. The microstructure of the steel is investigated in the area between the deformed and undistorted parts of the samples. The crystallography of the observed
twins and the slip bands is specified. The value of local plastic deformation within a micro area of a grain is measured, and the influence of microstructure on crack initiation is discussed.
Abstract: Large area well-aligned ZnO nanowire arrays have successfully been synthesized on an unconventional substrate: stainless-steel mesh at a low growth temperature of 400oC. The as-grown ZnO nanowires have uniform diameters about 20 nm and a strong UV peak was observed in photoluminescence spectra. The growth method provides a novel way to produce high quality ZnO nanowire arrays, and can be also used to direct the controllable growth of other nanomaterials.
Abstract: Large-scale single-crystalline In2O3 nanowires were successfully synthesized by simply evaporating the pure indium at 950ı. The as-synthesized products, characterized by XRD, SEM, and TEM, were pure, structurally uniform, and single crystalline with typical diameters of 10 to 100 nanometers and lengths of up to a few hundreds of micrometers. The growth mechanism of the nanowires also was discussed.
Abstract: PbTiO3 nano-sized powders were synthesized at 150oC by a new hydrothermal [denoted as sol-hydrothermal] method by using modified titanium tetra-n-butoxide and lead acetate as the precursors. Furthermore, tetragonal PbTi0.8O2.6 nano-sized powders were obtained by this method at 80oC. Compared with hydrothermal synthesis, the effect of temperature on the formation of products prepared by sol-hydrothermal was investigated. The characteristics of products were studied by XRD, TEM and SAXS. The results show sol-hydrothermal method choosing
acetylacetonate-modified titanium tetra-n-butoxide and lead acetate to form a sol could obtain PbTiO3 in 120nm size and PbTi0.8O2.6 powders with average diameter of 30nm, and both of them are pure tetragonal phase. In addition, PbTi0.8O2.6 could be converted into PbTiO3 gradually after annealed at giving condition.
Abstract: MS2(M=Mo, W, S=S, Se) are often used as solid lubricants in high/low temperature, high load, vacuum, in which oil lubrication is failed. Although WS2 is much more expensive than MoS2, it has better high temperature properties than MoS2. Thermal decomposition method is used to produce fullerence-like WS2 nanotube on Al2O3 template using (NH4)2WS4. The fabricated WS2
nanotube’s diameter is about 100nm and its length is longer than 2µm.The morphology, microstructure and tribological behavior of WS2 nanotube are investigated by means of SEM, TEM, XRD and AFM. The friction force between Si3N4 probe of AFM with WS2 nanotube is lower than that with MoS2 powder. Similar results are also found in pin-disc tester by GCr15 pin and lubricants
coating disc. The results of HETEM show that WS2 nanotube has rolling debris between the two antagonist surfaces, and MoS2 powder only has flattened debris. It may be the fullerence structure brings the chemical stability and leads to low friction.
Abstract: In this paper, we investigated the Raman scattering and photoluminescence of Zn1-xMnxO nanowires synthesized by the vapor phase growth. The changes of E2(High) and A1(LO) phonon frequency in Raman spectra indicate that the tensile stress increases while the free carrier concentration decreases with the increase of manganese. The Raman spectra exited by the different
lasers exhibit the quantum confinement effect of Zn1-xMnxO nanowires. The photoluminescence spectra reveal that the near band emission is affected by the content of manganese obviously. The values of IUV/G decrease distinctly with the manganese increase also demonstrate that more stress introduced with the more substitution of Mn for Zn.
Abstract: A novel Cu2O nano-whiskers with diameter of 6 ~ 12nm has been synthesized with the method of chemical deposition by adding surfactant cetyltrimethylammonium bromide (CTAB) as a template. The structure of the nano-whiskers has been characterized with XRD, SAED, TEM and XPS. The results show that the nano-whiskers exhibit a well crystallized 1D structure about 300 nm in length, and they are self-assembled by Cu2O quantum dots. Under visible light, the degradation
efficiency of p-chloronitrobenzene with the Cu2O nano-whiskers as photocatalyst can reach 85.8%.
Abstract: Two kinds of ZnO nanowires with different morphologies and characters were produced on Si (100) using a new PVD approach by heating and oxidizing Zn powders directly without any catalysts. The nanowires have an average diameter of 80nm (deposited at the evaporation source) and 30nm (deposited downstream of the evaporation source) respectively, and are evenly distributed over
an area of > 20mm2. The two nanowires have complete different photoluminescence properties. One has a strong green emission (510nm) with a weak UV emission (380nm). The other has a strong and sharp UV emission (385nm), showing the capability for UV laser emitters.
Abstract: Sr1-xBi2+yTa2O9 (x, y=0.2, 0) nanoparticles, synthesized by a sol-gel method, are investigated by X-ray diffraction and Raman spectroscopy. Large structure distortion shows the size effects in nanoparticles, which gives rise to the Raman bands broadening. The Bi content is the most important factor responsible for non-stoichiometric SrBi2Ta2O9 structure distortion and providing the larger ferroelectric spontaneous polarization and the higher Curie temperature. The stability of the crystal structure is discussed in consideration of inner compressive stress in
Abstract: Nanoparticles of MgO were successfully prepared in Triton X-100/n-hextnol/cyclohexane/water W/O microemulsion system. Basic preparation conditions were determined. TG-DTA showed that the proper calcination temperature was 450 oC. The nanoparticles were characterized by XRD and IR measurements in order to determine the crystal phase and component of the products. The morphological feature of the nanoparticles has been investigated by
TEM. The result of XRD pattern demonstrated that the particles were exactly indexed to a cubic rock salt structure of MgO. There are no organic or inorganic impurities appeared after 450 oC calcination. The result of TEM showed that the MgO nanoparticles were spherical and uniform. The UV-visible spectra demonstrated the phenomenon of absorption blue shift, which is the evidence
of quantum confinement effect, with the decrease of water/surfactant(R) value. Average size of the nanoparticles increased with increasing R value.