Photoemission and x-ray absorption study of MgC_(1-x)Ni_3

We investigated electronic structure of MgC_(1-x)Ni_3 with photoemission and x-ray absorption spectroscopy. Both results show that overall band structure is in reasonable agreement with band structure calculations including the existence of von Hove singularity (vHs)near E_F. However, we find that the sharp vHs peak theoretically predicted near the E_F is substantially suppressed. As for the Ni core level and absorption spectrum, there exist the satellites of Ni 2p which have a little larger energy separation and reduced intensity compared to the case of Ni-metal. These facts indicate that correlation effects among Ni 3d electrons may be important to understand various physical properties.Comment: 12 pages, 4 figure

Continuous cropping of endangered therapeutic plants via electron beam soil treatment and neutron tomography

Various medicinal plants are threatened with extinction owing to their over exploitation and the prevalence of soil borne pathogens. In this study, soils infected with root rot pathogens, which prevent continuous cropping, were treated with an electron beam. The level of soil borne fungus was reduced to amp; 8804;0.01 by soil electron beam treatment without appreciable effects on the levels of antagonistic microorganism or on the physicochemical properties of the soil. The survival rate of 4 year old plant was higher in electron beam treated soil 81.0 than in fumigated 62.5 , virgin 78 , or untreatedreplanting soil 0 . Additionally, under various soils conditions, neutron tomography permitted the monitoring of plant health and the detection of root pathological changes over a period of 4 6 years by quantitatively measuring root water content in situ. These methods allow continual cropping on the same soil without pesticide treatment. This is a major step toward the environmentally friendly production of endangered therapeutic herb

Raman characterization of strain and composition in small-sized self-assembled Si/Ge dots

A detailed Raman characterization of the structural properties of as-grown and annealed self-assembled Si/Ge dot multilayers is reported in this paper. Several new modes in as-grown or annealed Si/Ge dots and a frequency splitting of 4.2 cm(-1) between the longitudinal (LO) and transversal optical (TO) Ge-Ge modes in as-grown Si/Ge dots are observed in Raman spectra. An average Ge content of 0.8 and lateral strain of -3.4% are consistently obtained from these spectral features for as-grown Si/Ge dots with a lateral size of about 20 nm and a height of about 2 nm. It suggests that a certain amount of intermixing between Si spacer layers and Si/Ge dots takes place for the Si/Ge dot multilayers. The annealing behavior of the Ge-Si mode in Si/Ge dots indicates that the observed sharp Ge-Si mode is a Ge-Si alloy mode within the core regions of Si/Ge dots, rather than a Ge-Si interface mode in the interface regions of dots. The phonon strain-shift coefficients of the Ge-Ge and Ge-Si modes are determined for the small-sized Si/Ge dots with a high Ge content under a biaxial strain condition. The results show that the LO-TO frequency splitting of the Ge-Ge mode and the frequencies of the Ge-Ge and Ge-Si modes can be used as an efficient way to determine the average strain and composition in uncorrelated small-sized Si/Ge dot multilayers in which the mean strain field is close to the biaxial case