Interference in transport through double barriers in interacting quantum wires

We investigate interference effects of the backscattering current through a double-barrier structure in an interacting quantum wire attached to noninteracting leads. Depending on the interaction strength and the location of the barriers, the backscattering current exhibits different oscillation and scaling characteristics with the applied voltage in the strong and weak interaction cases. However, in both cases, the oscillation behaviors of the backscattering current are mainly determined by the quantum mechanical interference due to the existence of the double barriers.Comment: 6 pages, 3 fig

Spin relaxation in submonolayer and monolayer InAs structures grown in a GaAs matrix

Electron-spin dynamics in InAs/GaAs heterostructures consisting of a single layer of InAs (1/3-1 monolayer) embedded in (001) and (311)A GaAs matrix was studied by means of time-resolved Kerr rotation spectroscopy. The spin-relaxation time of the submonolayer InAs samples is significantly enhanced, compared with that of the monolayer InAs sample. The electron-spin-relaxation time and the effective g factor in submonolayer samples were found to be strongly dependent on the photogenerated carrier density. The contribution from both the D'yakonov-Perel' mechanism and Bir-Aronov-Pikus mechanism are discussed to interpret the temperature dependence of spin decoherence at various carrier densities. © 2009 The American Physical Society.published_or_final_versio

Inhibitory Effect of Polysaccharides from Scutellaria barbata D. Don on Invasion and Metastasis of 95-D Cells Lines via Regulation of C-MET and E-CAD Expressions

Purpose: To investigate the inhibitory effect of polysaccharides from Scutellaria barbata (PSB) on invasion and metastasis of lung cancer, and study the possible mechanism.Methods: PSB was extracted with water and by alcohol precipitation, and purified by DEAE-52 column chromatography. A highly invasive and metastatic lung carcinoma cell, 95-D cell line, was used for the study. Cell adhesion and invasion assays in vitro were performed to evaluate the anti-invasive and antimetastatic effects of PSB (50 - 200 μg/ml) on 95-D cell. Immunocytochemical staining and Western blot techniques were employed to study the regulatory effects of PSB on the expression of C-MET and ECAD.Results: The results indicate that PSB significantly inhibited cell invasion and migration of 95-D in a concentration-dependent manner (p < 0.05). The adhesion of 95-D cells to fibronectin was also inhibited by PSB (p < 0.05). The expression of C-MET and E-CAD in 95-D cells treated with PSB were significantly down-regulated and up-regulated, respectivelt (p < 0.05).Conclusion: Treatment with PSB can significantly inhibit the invasion and metastasis of 95-D cells in vitro, probably through the regulation of C-MET and E-CAD.Keywords: Polysaccharide, Scutellaria barbata, 95-D cell lines, Invasion, Metastasi

Magnetoelectric photocurrent generated by direct interband transitions in InGaAs/InAlAs two-dimensional electron gas

We report the observation of magnetoelectric photocurrent generated via direct interband transitions in an InGaAs/InAlAs two-dimensional electron gas by a linearly polarized incident light. The electric current is proportional to the in-plane magnetic field, which unbalances the velocities of the photoexcited carriers with opposite spins and consequently generates the electric current from a hidden spin photocurrent. The spin photocurrent can be evaluated from the measured electric current, and the conversion coefficient of spin photocurrent to electric current is self-consistently estimated to be 10-3-10 -2 per Tesla. The observed light-polarization dependence of the electric current is well explained by a theoretical model which reveals the wave vector angle dependence of the photoexcited carrier density. © 2010 The American Physical Society.published_or_final_versio

Multiterminal junctions formed by heating ultrathin single-walled carbon nanotubes

Author name used in this publication: S. Q. Shi2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Studies on fermentation of synthesizing poly-β - hydroxyalkanoate(pha) by sphaerotilus sp.

2000-2001 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Species composition, plant cover and diversity of recently reforested wild lands near Dabao Highway in Longitudinal Range-Gorge Region of Yunnan Province, China

Deforestation, over-cultivation and rural growth have severely damaged native vegetation of woodlands along roadsides in the Longitudinal Range-Gorge Region of Yunnan Province. This study wasconducted to evaluate the effect of different reforestation practices, which consisted of natural restoration or planting with tree seedlings that varied in species composition, coverage and diversity,on damaged roadside woodlands. Three randomly selected 10 m x 10 m plots in each reforestation practice were investigated. The results showed that the species composition, plant cover and speciesdiversity of the planted communities varied with reforestation strategies and time since planting. A higher number of species, proportion of native species and woody plants, canopy cover and speciesdiversity were found in naturally restored plots and in 3 - 4 year old plots that were planted with native plants. In the early stages of reforestation, herbs dominated the plant community in most plots, andwoody plants became more important with time after reforestation. Preliminary results suggest that plant height can be used an auxiliary indicator of plant cover to assess ecosystem function status ofthe restoration project. Also, evenness may be easier to restore than species richness. Natural restoration or reforestation with native dominant plants is a good management strategy for vegetationrestoration or improvement

One-step fabrication of biocompatible chitosan-coated ZnS and ZnS:Mn2+ quantum dots via a γ-radiation route

Biocompatible chitosan-coated ZnS quantum dots [CS-ZnS QDs] and chitosan-coated ZnS:Mn2+ quantum dots [CS-ZnS:Mn2+ QDs] were successfully fabricated via a convenient one-step γ-radiation route. The as-obtained QDs were around 5 nm in diameter with excellent water-solubility. These QDs emitting strong visible blue or orange light under UV excitation were successfully used as labels for PANC-1 cells. The cell experiments revealed that CS-ZnS and CS-ZnS:Mn2+ QDs showed low cytotoxicity and good biocompatibility, which offered possibilities for further biomedical applications. Moreover, this convenient synthesis strategy could be extended to fabricate other nanoparticles coated with chitosan

CNN Confidence Estimation for Rejection-Based Hand Gesture Classification in Myoelectric Control

Convolutional neural networks (CNNs) have been widely utilized to identify hand gestures from surface electromyography (sEMG) signals. However, due to the nonstationary characteristics of sEMG, the classification accuracy usually degrades significantly in the daily living environment involving complex hand movements. To further improve the reliability of a classifier, unconfident classifications are expected to be identified and rejected. In this study, we propose a novel approach to estimate the probability of correctness for each classification. Specifically, a confidence estimation model is established to generate confidence scores (ConfScore) based on posterior probabilities of CNN, and an objective function is designed to train the parameters of this model. In addition, a comprehensive metric that combines the true acceptance rate (TAR) and the true rejection rate (TRR) is proposed to evaluate the rejection performance of ConfScore, so that the tradeoff between system security and control lag could be fully considered. The effectiveness of ConfScore is verified using data from public databases and our online platform. The experimental results illustrate that ConfScore can better reflect the correctness of CNN classifications than traditional confidence features, i.e., maximum posterior probability and entropy of the probability vector. Moreover, the rejection performance is observed to be less sensitive to variations in rejection thresholds