Point Defects in Pb-, Bi-, and In-Doped CdZnTe Detectors: Deep-Level Transient Spectroscopy (DLTS) Measurements

We studied, by current deep-level transient spectroscopy (I-DLTS), point defects induced in CdZnTe detectors by three dopants: Pb, Bi, and In. Pb-doped CdZnTe detectors have a new acceptor trap at around 0.48?eV. The absence of a V_Cd trap suggests that all Cd vacancies are compensated by Pb interstitials after they form a deep-acceptor complex [[Pb_Cd]⁺-V _Cd ^2? ]^?. Bi-doped CdZnTe detectors had two distinct traps: a shallow trap at around 36?meV and a deep donor trap at around 0.82?eV. In detectors doped with In, we noted three well-known traps: two acceptor levels at around 0.18?eV (A-centers) and 0.31?eV (V_Cd), and a deep trap at around 1.1?eV.     

Cathodoluminescence investigation of silicon nanowires fabricated by thermal evaporation of SiO

Silicon nanowire samples fabricated by thermal evaporation of SiO powder were investigated by Cathodoluminescence. Three main bands were found at low temperatures, namely, peak 1 at about 620–650 nm (2.0–1.91 eV), peak 2 at 920 nm (1.35 eV), and peak 3 at 1280 nm (0.97 eV). An additional broad band (peak 4) in the infrared region with its maximum at ∼1570 nm (0.79 eV) appears at room temperature. The origins of the emission bands are discussed. The text was submitted by the authors in English.     

Phase Equilibria of BaO-R2O3-CuO z Systems (R = Y and Lanthanides) under CO2-free Conditions

For applications ranging from phase equilibria to the processing of second-generation high T _c superconductor-coated-conductors, phase diagrams constructed under carbonate-free conditions are needed. Subsolidus phase equilibria of BaO-R₂O₃-CuO _z (R = Ho) have been investigated at (810°C), 21 kPa (875°C) and 0.1 MPa (850 and 930°C) by applying controlled atmosphere methods to minimize the presence of carbonate and CO₂ and H₂O contamination. Under carbonate-free conditions, most of these phase diagrams are different from those reported in the literature. In this paper, we also review and compare the phase diagrams of ten BaO-R₂O₃-CuO _z systems (R = Nd, Sm, Eu, Gd, Dy, Y, Ho, Er, Tm and Yb) that were previously determined in this laboratory under Among these diagrams, a distinct trend of phase formation and tie-line relationships is observed.     

Multigrid geometric active contour models.

Geometric active contour models are very popular partial differential equation-based tools in image analysis and computer vision. We present a new multigrid algorithm for the fast evolution of level-set-based geometric active contours and compare it with other established numerical schemes. We overcome the main bottleneck associated with most numerical implementations of geometric active contours, namely the need for very small time steps to avoid instability, by employing a very stable fully 2-D implicit-explicit time integration numerical scheme. The proposed scheme is more accurate and has improved rotational invariance properties compared with alternative split schemes, particularly when big time steps are utilized. We then apply properly designed multigrid methods to efficiently solve the occurring sparse linear system. The combined algorithm allows for the rapid evolution of the contour and convergence to its final configuration after very few iterations. Image segmentation experiments demonstrate the efficiency and accuracy of the method.     

Genomic processing for cancer classification and prediction - Abroad review of the recent advances in model-based genomoric and proteomic signal processing for cancer detection

This article discusses signal processing and modelling of genomic and proteomic data from two cutting edge technologies, namely microarray technology and mass spectrometry (MS) technologies, as they are clearly among the leading frontiers that can reshape cancer study. The paper is organised as follows: first, a review of the few major design methodologies for cancer classification and prediction using genomic pr proteomic data. We then present an ensemble dependence model (EDM)-based framework and discuss the concept of dependence network. The EDM network is applied to both microarray gene expression and MS data sets in cancer study. We also present the performance-based idea and dependence network-based idea for biomarker identification. Our goal is to provide a broad review of the recent advances on model-based genomic and proteomic signal processing for cancer detection and prediction     

Modified null broadening adaptive beamforming: constrained optimisation approach

A constrained optimisation approach for null broadening adaptive beamforming is proposed. This approach improves the robustness of the traditional MVDR beamformer by broadening nulls for interference direction and the mainlobe for the desired direction. This optimisation is efficiently solved by semidefinite programming. The proposed approach, when applied to high altitude platform communications using a vertical linear antenna array, provides significantly better coverage performance than a previously reported null broadening technique     

Using Nonadditive Fuzzy Integral to Assess Performances of Organizational Transformation Via Communities of Practice

Organizational transformations have been widely adopted by firms who wish to improve their competitive advantage to be better prepared to face external challenges. This research has chosen Communities of Practice (CoPs) as the subject of discussion for an assessment model to reform organizations that undertake CoPs for collective knowledge to enhance their core competencies. Given the interrelationships between criteria, this research uses the nonadditive fuzzy integral to develop a framework for the CoPs performance assessment. The purposes of this paper are to identify the key dimensions/criteria in the CoPs, to use fuzzy logic method to analyze the relative importance of each criterion, and to rank the criteria so that proper resources can be allocated while managing the CoPs. Through interviews with experts, four strategy alternatives and 16 criteria along four dimensions are generated. A survey of the CoPs practitioners is then conducted to compare the results of each criterion. The results will not only help organizations that intend to initiate changes via the CoPs activities to decide the ranking of their appraisal criteria, but it can also assist them in guiding the behavior of their staff while effectively monitoring and improving the performances of the CoPs     

量子链和量子点光学特性的比较研究

比较研究了InGaAs/GaAs量子链和量子点的稳态和瞬态光学特性.实验发现,量子链的荧光寿命有很强的探测能量依赖关系,而量子点的荧光寿命随能量变化较小;量子链的荧光寿命随着激发功率迅速增加,高功率时趋于饱和,而量子点的荧光寿命随激发功率变化缓慢;此外,量子链样品的荧光上升时间也比量子点的小得多.这些结果清楚表明,在量子链结构中,参与发光的载流子之间存在很强的耦合和输运.进一步分析表明,这种耦合作用主要发生在量子链方向.荧光的偏振特性进一步证实了这一点.     

The Design and Construction of a Movable Image-Based Rendering System and Its Application to Multiview Conferencing

Image-based rendering (IBR) is an promising technology for rendering photo-realistic views of scenes from a collection of densely sampled images or videos. It provides a framework for developing revolutionary virtual reality and immersive viewing systems. While there has been considerable progress recently in the capturing, storage and transmission of image-based representations, most multiple camera systems are designed to be stationary and hence their ability to cope with moving objects and dynamic environment is somewhat limited. This paper studies the design and construction of a movable image-based rendering system based on a class of dynamic representations called plenoptic videos, its associated video processing algorithms and an application to multiview audio-visual conferencing. It is constructed by mounting a linear array of 8 video cameras on an electrically controllable wheel chair and its motion is controllable manually or remotely through wireless LAN by means of additional hardware circuitry. We also developed a real-time object tracking algorithm and utilize the motion information computed to adjust continuously the azimuth or rotation angle of the movable IBR system in order to cope with a given moving object in a large environment. Due to imperfection in tracking and mechanical vibration encountered in movable systems, the videos may appear very shaky and a new video stabilization technique is proposed to overcome this problem. The usefulness of the system is illustrated by means of a multiview conferencing application using a multiview TV display. Through this pilot study, we hope to disseminate useful experience for the design and construction of movable IBR systems with improved viewing freedom and ability to cope with moving object in a large environment.     

Features of the performance of a transient voltage suppressor in the pulsed mode

It is experimentally shown that the pulse withstand capacity of transient voltage suppressors, independent of power rating, decreases by the same law with increasing pulse duration, which indicates their optimum design parameters. The interrelation between transition times (turned on and off) and the characteristic parameters of the transient voltage suppressor structure is shown. The possibility of emitting a power fraction at the resonance frequency is an additional stimulus to increasing the withstand power.