Abstract

[(Mo,Sn)(Ti,Zr)14]Nb1 serial alloy compositions were designed using a cluster-plus-glue-atom model to receive BCC β-Ti alloys with low Youngs modulus (E) in Ti-based multi-component systems, where the square brackets enclose the coordination polyhedron cluster CN14 of the BCC structure and Nb is the glue atom. These serial alloys were prepared into rods with a diameter of 6 mm by copper-mould suction casting method. XRD and tensile test results indicated that all these alloy series possessed a monolithic BCC structure except [SnTi14]Nb1 and [(Mo0.5Sn0.5)Ti14]Nb1 due to Sn deteriorating BCC structural stability. A combination of Mo0.5Sn0.5 at the cluster center, as well as low-E Nb and Zr in the glue and cluster shell respectively, can reach simultaneously low E and high BCC stability, incarnated in the [(Mo0.5Sn0.5)(Ti13Zr)]Nb1 alloy which has the lowest E of 48 GPa in the suction-cast state.

100nm thin Mg/B precursor films were prepared on SiC substrates in ZZSX-500 vacuum coating machine. They were annealed by electron-beam(EB) which only took fractions of a second. In this paper the best annealing duration to fabricate the superconducting MgB2 thin films was investigated. Under the optimized annealing condition(accelerating voltage 15kV, electron beam current 5mA, annealing duration 0.7s), the superconducting MgB2 thin film with critical temperature Tconset~35.3 K and transition width ∆Tc~1K was fabricated. Besides that, a nano-bridge (about 100×200nm2) was etched on the superconducting MgB2 thin film by Focused Ion Beam (FIB). It’s a relative simple and efficient method. The nano-bridge exhibited the effect of Josephson junction with RSJ characteristics. At the same time a little loss of superconducting property was detected.

No abstract

.Adult Tessaratoma papillosa (Drury) (Hemiptera: Pentatomidae) secreted volatiles from metathoracic glands (MTG). Behavior and olfactory responses of adult bugs to their MTG secretions were tested using a Y-tube olfactometer and an electroantennogram (EAG). The results indicated that males were obviously attracted by female secretions and repelled by male secretions. Secretions of adult males elicited the greatest response of male antennae, whereas the lower response of male antennae to MTG secretions of adult females was recorded. The four compounds, (E)-2-octenal, undecane, dodecane and tridecane were tested for the EAG activity and behavior response with male adults at different concentrations. In EAG assays, the antenna of male T. papillosa showed the highest sensitivity to (E)-2-octenal (10 μL /μL) and the second highest sensitivity to undecane (10 μL /μL), but a similar sensitivity to other stimuli. Unlike EAG results, males were attractive to (E)-2-octenal (10-2 and 10-1 μL /μL) and tridecane (10 μL /μL), and repelled by (E)-2-octenal (10-3, 1, 10 and 102 μL /μL) and tridecane (10-1 μL /μL) in the Y-tube olfactometer. Our data suggested that (E)-2-octenal and tridecane may be part of a complex pheromone system in T. papillosa.