Effects of Spartina alterniflora invasion on distribution of Moerella iridescens in a tidal flat of western Pacific Ocean

The invasion of Spartina alterniflora significantly affected the local ecosystem of Western Pacific Ocean where Moerella iridescens lives. Five patches with different invasion stages of S. alterniflora were selected and the influence on distribution of M. iridescens was studied on the coast of Wenzhou Bay, China in 2007. The aggregated distribution pattern was proved by using Taylor's power regression and Iwao's plot regression methods (p<0.001). The densities were significantly affected by the factors of S. alterniflora invasion stage and season (p<0.001), but no significant effect of interaction (p=0.805) occurred. M. iridescens mainly clumped in the habitats of no invasion and initial invasion of S. alterniflora was in the high tidal zone, and the lowest density was recorded where complete invasion occurred. The densities were larger in warmer than in cooler seasons. There were significant positive correlations among the average densities in seasons. Density variation must be the response of M. iridescens to the environment, including S. alterniflora invasion stage, temperate stress and interspecific associations

Generation of high-energy-density ion bunches by ultraintense laser-cone-target interaction

A scheme in which carbon ion bunches are accelerated to a high energy and density by a laser pulse (similar to 10(21) W/cm(2)) irradiating cone targets is proposed and investigated using particle-in-cell simulations. The laser pulse is focused by the cone and drives forward an ultrathin foil located at the cone's tip. In the course of the work, best results were obtained employing target configurations combining a low-Z cone with a multispecies foil transversely shaped to match the laser intensity profile. (C) 2014 AIP Publishing LLC

THE TEMPERATURE CHARACTERISTICS OF THE PHOTOLUMINESCENCE FROM GaAs-GaAlAs MULTIPLE QUANTUM WELL STRUCTURES

The temperature behavior of the photoluminescence from GaAs-GaAlAs multiple quantum well structures indicates that the maintaining of the excitonic properties of the luminescence at higher temperature is a good assessment of the material quality, and the temperature dependence of the luminescence intensity ratio from the intentionally arranged wide and narrow wells is discussed by the vertical transport process of the photoexcited electrons

Resonant Raman scattering and photoluminescence emissions from above bandgap levels in dilute GaAsN alloys

The transitions of E₀, E₀ + Δ₀, and E₊ in dilute GaAs_1-xN_x alloys with x = 0.10%, 0.22%, 0.36%, and 0.62% are observed by micro-photoluminescence. Resonant Raman scattering results further confirm that they are from the intrinsic emissions in the studied dilute GaAsN alloys rather than some localized exciton emissions in the GaAsN alloys. The results show that the nitrogen-induced E₊ and E₀ + Δ₀ transitions in GaAsN alloys intersect at a nitrogen content of about 0.16%. It is demonstrated that a small amount of isoelectronic doping combined with micro-photoluminescence allows direct observation of above band gap transitions that are not usually accessible in photoluminescence

Optical study of localized and delocalized states in GaAsN/GaAs

Taking advantages of short pulse excitation and time-resolved photoluminescence (PL), we have studied the exciton localization effect in a number of GaAsN alloys and GaAsN/GaAs quantum wells (QWs). In the PL spectra, an extra transition located at the higher energy side of the commonly reported N-related emissions is observed. By measuring PL dependence on temperature and excitation power along with PL dynamics study, the new PL peak has been identified as a transition of the band edge-related recombination in dilute GaAsN alloy and delocalized transition in QWs. Using selective excitation PL we further attribute the localized emission in QWs to the excitons localized at the GaAsN/GaAs interfaces. This interface-related exciton localization could be greatly reduced by a rapid thermal annealing