Mode coupling dynamics and communication strategies for multi-core fiber systems

2011-2012 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Interface characterisation and internal electric field evaluation of a-Si:H pin solar cell by variable energy positron annhilation spectroscopy

Symposium Theme: Amorphous and microcrystalline silicon technologyBy means of the slow positron beam Doppler-broadening technique, the depth profile of microvoids across a p-i-n double junction solar cell has been resolved. VEPFIT fitting results indicate an approximately uniform density of the defects throughout the solar cell, but with an enhanced concentration at all of the interfaces possibly due to network mismatch. In order to evaluate the internal electric field, Variable Energy Positron Annihilation Spectroscopy (VEPAS) measurements have been performed on a single junction pin solar cell at different biases. The internal electric field effect on positrons has also been examined in terms of the bias dependence of positron drift in a-Si:H single junction pin solar cell.published_or_final_versio

Identification of vacancy-like defects in high-rate grown a-Si before and after ligh soaking by vepas

Symposium Theme: Amorphous and microcrystalline silicon technologyWe show how positron annihilation can distinguish vacancies in undoped hydrogenated amorphous silicon by performing Variable Energy Positron Annihilation Spectroscopy experiments before and after light soaking. We find that vacancy clusters, di-vacancies and a new type of single vacancies are created in undoped as-grown a-Si:H thin film by light illumination. The fact that the vacancy clusters are eliminated by the thermal annealing suggests that the Staebler-Wronski effect is closely related to vacancy clusters in a-Si:H material. The creation of vacancy clusters and redistribution of di-vacancies and even single vacancies probably result in photo-induced structural changes in this material.published_or_final_versio

Predicting 1-year risk for relapse in patients who have discontinued or continued quetiapine after remission from first-episode psychosis

Objective: Relapse is common among patients with psychotic disorders. Identification of relapse predictors is important for decision regarding maintenance medication. Naturalistic studies often identify medication non-adherence as a dominant predictor. There are relatively few studies for predictors where adherence is already known. It is this situation i.e., discontinuation of medication that predictors will be most useful. We identify predictors for relapse in situations of (i) discontinuation and (ii) continuation of maintenance medication. Method: Analysis of relapse predictors is based on a randomized controlled study (n= 178) comparing relapse rates between patients who discontinued or continued medication for at least 1. year following first-episode psychosis. Demographic, clinical and neurocognitive variables were assessed at baseline as predictors of relapse within 1. year. Results: Risk of relapse was 79% in the discontinuation group and 41% in the maintenance group. Predictors in the discontinuation group were diagnosis of schizophrenia, poorer semantic fluency performance, and higher blink rate. Predictors in the continuation group were disinhibition soft signs and more general psychopathology symptoms. Conclusion: Different predictors of relapse were identified for first episode psychosis patients who discontinued and continued maintenance medication. Neurocognitive dysfunctions are important predictors for both groups. While signs of frontal dysfunction and dopamine hyperactivity predict relapse in the discontinuation group, sign of cognitive disinhibition predicts relapse in the continuation group. © 2013 Elsevier B.V.link_to_subscribed_fulltex