NBTI and hot-carrier effects in accumulation-mode Pi-gate pMOSFETs

Negative bias temperature instability (NBTI) and hot-carrier induced device degradation in accumulation-mode Pi-gate pMOSFETs have been studied for different fin widths ranging from 20 to 40 nm. The NBTI induced device degradation is more significant in narrow devices. This result can be explained by enhanced diffusion of hydrogen at the corners in multiple-gate devices. Due to larger impact ionization, hot-carrier induced device degradation is more significant in wider devices. Finally, hot-carrier induced device degradation rate is highest under stress conditions where V_GS = V_TH.     

Elucidating the Impact of Mg Substitution on the Properties of NASICON-Na3+yV2−yMgy(PO4)3 Cathodes

Vanadium multiredox-based NASICON-Na_zV_2−yM_y(PO₄)₃ (3 ≤ z ≤ 4; M = Al³⁺, Cr³⁺, and Mn²⁺) cathodes are particularly attractive for Na-ion battery applications due to their high Na insertion voltage (>3.5 V vs Na⁺/Na⁰), reversible storage capacity (≈150 mA h g⁻¹), and rate performance. However, their practical application is hindered by rapid capacity fade due to bulk structural rearrangements at high potentials involving complex redox and local structural changes. To decouple these factors, a series of Mg²⁺-substituted Na_3+yV_2−yMg_y(PO₄)₃ (0 ≤ y ≤ 1) cathodes is studied for which the only redox-active species is vanadium. While X-ray diffraction (XRD) confirms the formation of solid solutions between the y = 0 and 1 end members, X-ray absorption spectroscopy and solid-state nuclear magnetic resonance reveal a complex evolution of the local structure upon progressive Mg²⁺ substitution for V³⁺. Concurrently, the intercalation voltage rises from 3.35 to 3.45 V, due to increasingly more ionic V O bonds, and the sodium (de)intercalation mechanism transitions from a two-phase for y ≤ 0.5 to a solid solution process for y ≥ 0.5, as confirmed by in operando XRD, while Na-ion diffusion kinetics follow a nonlinear trend across the compositional series.     

An early comparison between endoscopic ultrasound-guided fine-needle aspiration and mediastinoscopy for diagnosis of mediastinal malignancy

Precise mediastinal lymph node staging is essential in non-small cell lung cancer for proper evaluation and treatment. In addition to CT, mediastinoscopy is routinely used for staging and diagnosis of mediastinal malignancy. Recently, endoscopic ultrasound (EUS) combined with fine-needle aspiration (FNA) biopsy has been used to evaluate mediastinal disease. The purpose of this study was to assess and compare mediastinoscopy with EUS/FNA in the evaluation of mediastinal masses. From August 1995 to July 1997, 21 patients with suspected mediastinal malignancy underwent cervical mediastinoscopy with biopsy. During this same period, seven patients with suspected mediastinal malignancy were evaluated using EUS/FNA. All patients were retrospectively studied. Both mediastinoscopy and EUS/FNA were highly sensitive in diagnosing mediastinal malignancy (100% and 86%, respectively). Specificity and positive predictive value were 100 per cent for both procedures. Mediastinoscopy and EUS/FNA are highly accurate methods of staging mediastinal malignancy. Mediastinoscopy provides better access to the upper and anterior mediastinum, whereas EUS/FNA can safely be used to biopsy subcarinal and posterior mediastinal masses. Mediastinoscopy and EUS/FNA target different areas of the mediastinum and may be complimentary in the evaluation of mediastinal malignancy and staging of bronchogenic carcinoma.     

Comparison of different surface orientation in narrow fin MuGFETs

Device performance characteristics are investigated for different surface orientation and doping concentration on accumulation-mode p-type and inversion-mode n-type MuGFETs. Short-channel effects and drain breakdown voltage are better is carrier transport is in the (1 0 0) direction than in the (1 1 0) direction. This is due to the larger Si/SiO₂ interface roughness, the higher density of interface state at (1 1 0) surfaces, and to the difference of effective mass. The mobility in PMOS devices, however, is much higher in the (1 1 0) direction than that in the (1 0 0) direction. For better performance of device, our results show that optimized fin orientation can improve device stability and performance.     

Enhanced photoelectrochemical water splitting efficiency: Increasing the photo anode’s properties by doping on the fluorine doped tin oxide glass surface

The recent accomplishments in using Sn or Ge, Mn and Ti-doped hematite photoanodes for solar water splitting are highlighted in this paper. Magnetron sputtering and hydrothermal methods were applied for depositing the alloyed films on Fluorine doped Tin Oxide (FTO) glasses. Results were compered by structural and morphology analysis using scanning electronic microscopy (SEM) images and XRD. Similarly, a comparison was done by using optical properties and photocatalytic activities. Doping elements for all samples illustrated higher photocurrent density to compare un-doped hematite. This research confirms that doped elements enhance the charge carriers and reduce the recombination losses, and it emphasizes that these treatment results in better photoelectrochemistry performance of Fe₂O₃ nanostructured photoanodes.     

All-optical photonic crystal AND,XOR, and OR logic gates using nonlinear Kerr effect and ring resonators

In this article, two structures are proposed for all-optical AND, XOR, and OR logic gates based on nonlinear photonic crystals. The proposed structures include a Y-junction and ring resonator-based limiters. Two different structures are designed as the limiter in order to produce AND–XOR and AND–OR logic gates. Nonlinear rods of proposed structure have been used in order to create the frequency shift for different values of input power. Finite difference time domain method has been utilized to simulate the performance of proposed logic gates. Simulation results show that the smallest ON–OFF logic-level contrast ratio for the structures proposed for AND–XOR and AND–OR logic gates are 20.29 dB and 16.7 dB, respectively.     

Alias-Component Matrices of Nonuniform Transmultiplexers

Nonuniform transmultiplexers can be used for interconversion of signals with different sampling rates between the time-division multiplexing format and the frequency-division multiplexing format. Here, we review the polyphase representation and discuss the ℋ_∞ model-matching design of finite impulse response nonuniform transmultiplexers by semidefinite programming. Then, we study the alias-component matrices. It will be shown that the alias-component matrices of nonuniform transmultiplexers are generalizations of those of linear periodically time-varying systems. In particular, it is shown that the output at any given frequency is only dependent on the input at a finite set of frequencies. This work was supported by the Natural Sciences and Engineering Research Council of Canada.     

Decentralized DES Supervisory Control for Coordination of ULTC and SVC

This paper discusses the issues involved in modeling and synthesizing a discrete‐event supervisory control system in a decentralized structure to coordinate the behavior of an under‐load tap‐changing transformer (ULTC) and a static VAR compensator (SVC) in electrical power systems. The control specifications are modeled as some automata, and it is shown that they are controllable. The designed closed‐loop control system is non‐blocking. The consistency of the high‐level model in a two‐level hierarchical control system is investigated. The proposed supervisory control is tested by inspecting its behavior in a simulated situation. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society