Insect mortality studies were performed with a high-power microwave source operating at a frequency of 10.6 GHz at power levels of 9-20 kW to irradiate samples of soft wite wheat, Triticum aestivum (L.), infested with maize weevil, Sitophilus zeamais Motschul-sky, and ground wheat infested with red flour beetle, Tribolium castaneum (Herbst). These pests are common internal and external feeders in stored products, respectively. Samples at various age intervals from egg to adult were exposed. The results support the hypothesis that the insect-to-host dissipation ratio increases at frequencies >2.45 GHz. Mean mortalities 93% occurred for all ages of S. zeamais and 94% for adults and larvae of T. castaneum for mean specific input energies of 51 J/g and 53 J/g, respectively, indicating that S. zeamais is more susceptible.
Using quasielastic neutron scattering, we have studied the self-diffusion of alkali-metal atoms in stage-1 and stage-2 graphite intercalation compounds.For stage-1 compounds the diffusion proceeds via jumps to potential wells provided by the graphite substrate potential. The activation energies for diffusion in LiC6 and KC8 are 1.0 and 0.18 eV, respectively, and agree very well with theoretical values derived by Mele [Phys. Rev. B 32, 2538 (1985)] for the saddlepoint energy between C -C bonds. The diffusion of alkali-metal atoms in stage-2 compounds is qualitatively very different from that in stage-1 compounds. The characteristics of the diffusive motion appear to be intermediate between those of a free liquid and a lattice liquid. The activation energies are considerably lower and compare with those of hydrogen in metals: E, =0.126, 0.063, and 0.077 eV for K, Rb, and Cs, respectively, in stage-2 compounds. Moreover, the stage-2 compounds exhibit a continuous melting transition, which extends over several hundred degrees centigrade. Over this temperature range, liquidlike diffusive motion and solidlike phonon excitations coexist. We argue that this behavior is characteristic of the melting of a two-dimensional structure on a periodic substrate.
A detailed X-ray study of HOPG reveals extensive wings on the 00.1 Bragg reflections whose width in a scan normal to 00.l is comparable to the mosaic spread. These wings, which are absent in singlecrystal profiles, are attributed to rotational or twist (T) defects between perfect substacks of pyrolyzed graphite. Along 11.1, the twists destroy coherence and produce an effective 'particle-size' broadening. The average substack size, or spacing between T defects, is estimated through profile fitting to be about 110 A,. The lateral extent of T defects is comparable to a mosaic-block size.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.