High purity one-dimensional ZnO nanobelts were synthesized by thermally evaporating commercial ZnS powders in a hydrogen-oxygen mixture gas at 1050 degrees C. It was found that these ZnO nanobelts had a single crystal hexagonal wurtzite structure growing along the [0001] direction. They had a rectangle-shaped cross-section with typical widths of 20 to 100 nanometers and lengths of up to hundreds of micrometers with lattice constants of a = 0.325 nm and c = 0.520 nm. The self-catalytic hydrogen-oxygen assisted growth of ZnO nanobelt is discussed. The photoluminescence (PL) characterization of the ZnO nanobelts shows strong near-band UV emission (about 383 nm) and one broad peak at 501 nm, which indicates that the ZnO nanobelts have good potential application in optoelectronic devices.

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As further research on space exploration and space platform technology, space-based electromagnetic launchers (EML) have aroused widespread attention and interest. This paper presents analysis and optimization of ironless permanent magnet linear synchronous motor (ILPMLSM) which easily meet requirements such as fast response, light weight, small volume and high precision positioning for space-based EML. Electromotive thrust and thrust per volume of ILPMLSM with non-overlapping and overlapping air-cored windings are compared based on the analysis of the magnetic field. It is shown that the overlapping winding machine has certain important advantages compared to the non-overlapping winding machine for space platform. Further, we propose a design optimization to improve thrust density and thrust ripple simultaneously by optimizing structure and dimensions of magnets and windings.The design optimization is verified by 2-D Finite Element analysis.Index Terms-linear electromagnetic launchers, overlapping windings, thrust density, optimization, Halbach permanentmagnet array,finite-element analysis (FEA).