We propose a simple and catalyst-free method to grow quasi-aligned single crystalline Cu(3)Mo(2)O(9) nanorods in terms of a mechanism differing from the conventional vapor-solid (VS) and vapor-liquid-solid (VLS) ones for chemical vapor deposition (CVD) methods by directly heating Cu foils in a mixed atmosphere of MoO(3) vapor and air. High quality Cu(3)Mo(2)O(9) nanorods can be simply grown in a temperature range from 450 to 550 degrees C whose diameter, length, and distribution density are dependent on both heating temperature and time. Interestingly, the growth rate at 550 degrees C drops significantly after 6 h. All nanorods grow along the [010] direction. On the basis of a proposed growth model, the nucleation of Cu(3)Mo(2)O(9) nanorods is believed to be governed by formation of initial polycrystalline Cu(x)O protuberances with nanoscale diameters on Cu foils which may act as growth "templates". This novel method can be applied to grow other similar tertiary transition metal oxide nanostructures on substrates with large sizes. Most importantly, these Cu(3)Mo(2)O(9) nanorods decrease the ignition temperature of Printex U model soot from 600 to 438 degrees C, being in between 200 and 450 degrees C of the exhaust of diesel-powered combustion engines, which are therefore expected to be a potential efficient and environmentally friendly catalyst for diesel exhaust combustion.

Slope failure behaviour of noncohesive media with the consideration of gravity and ground excitations is examined using the two-dimensional combined finite-discrete element method (FDEM). The FDEM aims at solving large-scale transient dynamics and is particularly suitable for this problem. The method discretises an entity into a couple of individual discrete elements. Within each discrete element, the finite element method (FEM) formulation is embedded so that contact forces and deformation between and of these discrete elements can be predicted more accurately. Noncohesive media is simply modelled with assembly of individual discrete elements without cohesion, that is, no joint elements need to be defined. To validate the effectiveness of the FDEM modelling, two examples are presented and compared with results from other sources. The FDEM results on gravitational collapse of rectangular soil heap and landslide triggered by the Chi-Chi earthquake show that the method is applicable and reliable for the analysis of slope failure behaviour of noncohesive media through comparison with results from other known methods such as the smoothed particle hydrodynamics (SPH), the discrete element method (DEM) and the material point method (MPM).

Small-angle X-ray scattering (SAXS) is an effective method to obtain microstructural information of materials. However, due to the influence of crystal surface effects, SAXS has a deviation in the characterization of the crystal microstructure. In order to solve the influence of crystal surface effect on the internal defect signal, the microstructure of Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) crystal was characterized by soaking the sample in the matching solution. We found that the absolute scattering intensity, specific surface and volume fraction of the sample in the matching solution are significantly lower than the initial sample, which solves the influence of the crystal surface effect on the test results. Comparing the scattering results of the samples in different electron density matching solutions, it was found that the best result was obtained when using GPL-107 perfluoropolyether (PFPE) matching solution and the same law was obtained by controlling the experiment with 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20) crystal. The fitting density was calculated according to the theoretical density and void volume fraction of the sample, and the calculated results are close to the test results of Particle Density Distribution Analyzer (PDDA). Based on this paper, we provide a method to obtain the correct information of crystal microstructure.