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M. Liu Q. Fang G. He L.Q. Zhu S.S. Pan L.D. Zhang 《Materials Science in Semiconductor Processing》2006,9(6):876
High-k HfOxNy thin films have been grown by radio frequency (rf) reactive sputtering of metal Hf target in N2/Ar/O2 ambient at different substrate temperatures. The chemical compositions of the films have been investigated as a function of substrate temperature by X-ray photoelectron spectroscopy (XPS). XPS measurements showed that nitrogen concentration increases with an increase in substrate temperature. Room-temperature spectroscopic ellipsometry (SE) with photon energy 0.75–6.5 eV was used to investigate the optical properties of the films. SE results demonstrated that refractive index n increases with an increase in substrate temperature. Based on TL parameters which were obtained from the best fit results used in a simulation of the measured spectra, meanwhile, we conclude that the energy band gap (Eg) decreases with an increase in substrate temperature. 相似文献
985.
986.
A Novel Segmentation and Feedback Model for Resolving Contention in Optical Burst Switching 总被引:2,自引:0,他引:2
A novel segmentation and feedback model (SFM) applied to resolve contention is proposed. Simulation and performance analyses show that the SFM effectively avoids contentions in optical burst switching (OBS). The long delay time of deflection routing and the immature technology of wavelength converters and optical buffers are not deployed in the SFM. The SFM does not only realize fast switching but also allows preemption by higher priority bursts. 相似文献
987.
988.
Many recent studies have convincingly demonstrated that network traffic exhibits a noticeable self-similar nature, which has a considerable impact on network performance, and most studies of optical burst switching (OBS) networks are under a fundamental assumption that full wavelength conversion is available throughout the network. In practice, however, economic and technical considerations are likely to dictate a more limited and sparse deployment of wavelength converters in the optical network. Therefore, we present a novel scheme for OBS networks, called logical cascaded private subnet (LCPN) with start wavelength assignment policy. We define the concept of canoe relative to cluster in self-similar traffic, and introduce a new device named payload segregator at the edge node as a gateway to the core node in OBS Networks. According to the changes in the edge node framework, we put forward the concept of cluster private subnet and canoe private subnet in the core node correspondingly. A new start wavelength assignment policy is proposed for the absence of (full) wavelength conversion capabilities in the core node of OBS Networks. The performance study indicates that, our new scheme is robust under self-similar traffic and wavelength continuity constraint. 相似文献
989.
This study focuses on numerical simulation of ductile failure in the Co binder phase of WC–Co hardmetal. The growth of edge cracks under mode I loading is considered. A computational micromechanics approach is taken where the Co binder ligaments are explicitly represented in finite element models. An embedding technique is employed. Crystal plasticity theory is used to represent plastic deformation in the Co ligaments. Crack propagation in the binder is simulated using an element removal technique based on a modified Rice and Tracey model for ductile void growth, and fracture resistance curves are generated. Parameter studies are performed for variations in microstructrual parameters such as numbers of Co ligaments ahead of the crack tip and local Co volume fraction. The importance of thermal residual stresses and finite element mesh density are also investigated. 相似文献
990.
The aim of this research is to investigate how ammonia treatment of the surface can influence the activity of a viscose-based activated carbon cloth (ACC) for the oxidative retention of H2S and SO2 in humid air at 25 °C. Surface basic nitrogen groups were introduced either by treatment with ammonia/air at 300 °C or with ammonia/steam at 800 °C. The pore structure of the samples so prepared was examined by adsorption measurements. Changes in the surface chemistry were assessed by X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and temperature programmed desorption (TPD). The change of ACC activity could not be merely attributed to surface nitrogen groups but to other changes in the support. Ammonia/steam treatment improved ACC performance the most, not only by introducing nitrogen surface groups, but also by extending the microporosity and by modifying the distribution of surface oxygen groups. Successive adsorption-regeneration cycles showed important differences between oxidative retention of H2S and SO2 and the subsequent catalyst/support regeneration process. 相似文献