Shallow-terrace-like interface in dilute-bismuth GaSb/AlGaSb single quantum wells evidenced by photoluminescence

Photoluminescence (PL) measurements are performed on one GaSb/AlGaSb single-quantum-well (SQW) sample and two dilute-bismuth (Bi) GaSb/AlGaSb SQW samples grown at 360 and 380 °C, at low temperatures and under magnetic fields. Bimodal PL features are identified in the dilute-Bi samples, and to be accompanied by abnormal PL blueshift in the sample grown at 360 °C. The bimodal PL features are found to be from similar origins of band-to-band transition by magneto-PL evolution. Analysis indicates that the phenomenon can be well interpreted by the joint effect of interfacial large-lateral-scale islands and Al/Ga interdiffusion due to Bi incorporation. The interdiffusion introduces about 1-monolayer shrinkage to the effective quantum-well thickness, which is similar to the interfacial islands height, and the both together result in an unusual shallow-terrace-like interface between GaSbBi and AlGaSb. A phenomenological model is established, the Bi content of isoelectronic incorporation and the exciton reduced effective mass are estimated for the GaSbBi sample grown at 380 °C, and a value of about 21 meV/% is suggested for the bandgap bowing rate of GaSbBi. An effective routine is suggested for determining the Bi content and the depth of the shallow-terraces at interface in dilute-Bi SQW structures

Synchronization Control for Stochastic Neural Networks with Mixed Time-Varying Delays

Synchronization control of stochastic neural networks with time-varying discrete and continuous delays has been investigated. A novel control scheme is proposed using the Lyapunov functional method and linear matrix inequality (LMI) approach. Sufficient conditions have been derived to ensure the global asymptotical mean-square stability for the error system, and thus the drive system synchronizes with the response system. Also, the control gain matrix can be obtained. With these effective methods, synchronization can be achieved. Simulation results are presented to show the effectiveness of the theoretical results

«Conselho de amigo, aviso do céu»: contributos para a análise semântico-pragmática dos atos ilocutórios de conselho e de aviso em confronto com o de ameaça

Com base em exemplos de um corpus oral de Português Europeu, o presente texto discute a organização e funcionamento do ato ilocutório de conselho e de aviso, destacando as semelhanças e diferenças entre eles e os atos de discursos como ameaças e promessas, avisos hipotéticos e ameaças condicionais. Depois da análise das noções do “querer dizer NN” de Grice e de “uptake” de Austin, destacamos a importância da relação entre intenção e convenção na análise dos atos ilocutórios de Searle com o levantamento das regras que determinam os indicadores de força ilocutória. A interpretação dos valores ilocutórios na sequencialidade das intervenções destaca a relação entre práticas discursivas e figuração.info:eu-repo/semantics/publishedVersio

An animal model of SARS produced by infection of Macaca mulatta with SARS coronavirus.

A new SARS animal model was established by inoculating SARS coronavirus (SARS-CoV) into rhesus macaques (Macaca mulatta) through the nasal cavity. Pathological pulmonary changes were successively detected on days 5-60 after virus inoculation. All eight animals showed a transient fever 2-3 days after inoculation. Immunological, molecular biological, and pathological studies support the establishment of this SARS animal model. Firstly, SARS-CoV-specific IgGs were detected in the sera of macaques from 11 to 60 days after inoculation. Secondly, SARS-CoV RNA could be detected in pharyngeal swab samples using nested RT-PCR in all infected animals from 5 days after virus inoculation. Finally, histopathological changes of interstitial pneumonia were found in the lungs during the 60 days after viral inoculation: these changes were less marked at later time points, indicating that an active healing process together with resolution of an acute inflammatory response was taking place in these animals. This animal model should provide insight into the mechanisms of SARS-CoV-related pulmonary disease and greatly facilitate the development of vaccines and therapeutics against SARS