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41.
海洋拥有巨大的能源资源潜力,而储能技术是新能源革命的关键,推动海上储能技术发展势在必行。本文首先阐述了海上储能技术的出现与发展,以风电、锂电、多能互补技术在海上储能的实际应用为例,介绍了储能技术从陆地到海洋的技术转移模式。其次列举了能够利用海水特点、适应海洋环境的储能技术与形式。海水运动虽复杂多变却蕴含丰富的能量,纳米发电机能够对海水运动能量进行有效收集。最后从长期、短期、应用场景三方面展望了海上储能技术的发展前景,总结指出海上储能技术在清洁开发利用海洋能源中的重要性以及推进海上储能技术发展在新能源革命时代的必要性。 相似文献
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43.
Uniaxial compressive behavior of Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass at room temperature was characterized with high-sensitivity strain gauges directly attached to test samples. Displacement–time curves exhibited micron-size serrations (or bursts) after the onset of yielding, apparently associated with discrete shear band formation. Each displacement burst disclosed three-step (acceleration, steady-state, and deceleration) process in shear band propagation. The viscosity of a propagating shear band was found to be relatively low and, actually, in a similar range usually measured in the supercooled liquid region. A detailed analysis of the experimental results using a self-consistent Vogel–Fulcher–Tamann (VFT) equation based on free volume model suggested that shear band propagation was mainly resulted from free volume accumulation. 相似文献
44.
A ductile phase-separated Zr-based bulk metallic glass (BMG) deformed to different strains at room temperature and low strain rate was characterized. The BMG samples were compressed to nominal strains of 3%, 7%, and 10%, after which the samples were unloaded for morphological observation using scanning electron microscopy. The morphological observation was subsequently used for the interpretation of the measured load–displacement curves. It was found that the BMG exhibited apparent uniform deformation initially (at plastic strain <1%) and, then, visible local shear bands began to developed. Afterwards, a principal shear band was soon developed and dominated the deformation process until fracture. In this study, we also found that the local shear strain varies along the principal shear plane and decreases monotonically from the shear band initiation site. 相似文献
45.
Akihiko Hirata Yoshihiko Hirotsu Satoru Kuboya T.G. Nieh 《Journal of Alloys and Compounds》2009,483(1-2):64
Local structural fluctuation in relation to the medium range order (MRO) in a Pd–Ni–P bulk metallic glass was examined using nanobeam electron diffraction (NBED) technique. We found diffraction spots with strong intensities in the NBED patterns taken from any observation sites in the specimen. This indicates a presence of MRO regions densely formed in the specimen. The diffraction spots in NBED were normally dispersed around positions corresponding to the first halo-diffraction ring in selected area diffraction. A low-temperature annealing led to form a nanocrystalline microstructure consisting of unidentified phosphides. In the course of annealing, the MRO structures deduced from the NBED patterns have no structural similarity to the phosphides found in the primary crystallization stage. The MRO structure changes into a similar structure with the primary crystals just before the crystallization. A discussion is made for the MRO structure and its relation to the glass stability and also to the phosphide nucleation in the primary crystallization. 相似文献
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47.
Selection and performance comparison of jet fuel surrogates for autothermal reforming 总被引:3,自引:0,他引:3
Three fuel mixtures were investigated as possible surrogates for low-sulfur JP-8. The selected fuel mixtures were chosen based on a desire to match hydrocarbon chemical composition classes found in real jet fuels. The surrogate fuels selected consisted of single, binary and tertiary-component mixtures of n-dodecane, decalin and toluene in liquid volume ratios of 10:0:0, 9:1:0 and 7:1:2. The hydrocarbon components selected represented the largest chemical classes within JP-8 of normal paraffin, cyclo-paraffin and aromatic. The surrogate fuels and individual surrogate fuel components were reacted in an atmospheric pressure autothermal reformer with noble metal catalysts under conditions of steam-to-carbon ratio of 2.0, fuel equivalency energy flow of 3.3 kW thermal, space velocities of 21,000-28,000 h−1 and variable oxygen-to-carbon ratios of 0.8-1.2. For all fuels investigated fuel conversion of greater than 96% could be achieved. The single component n-dodecane proved to be the least reactive resulting in lower hydrogen yields, lower reforming efficiency and increased olefin products in the reformate. The binary mixture of n-dodecane and decalin resulted in a closer match with JP-8, but did not correlate well in terms of fuel conversion and hydrogen yield. Aliphatic mixtures also exhibited greater olefin production. The three-component mixture of n-dodecane/decalin/toluene provided the best correlation to JP-8 and appears to be a good three-component surrogate fuel, particularly over the operating range of oxygen to carbon ratio of 0.95-1.10. 相似文献
48.
Hag-Ju Cho Chang Seok Kang Onishi K. Gopalan S. Nieh R. Rino Choi Krishnan S. Lee J.C. 《Electron Device Letters, IEEE》2002,23(5):249-251
A novel technique to control the nitrogen profile in HfO2 gate dielectric was developed using a reactive sputtering method. The incorporation of nitrogen in the upper layer of HfO2 was achieved by sputter depositing a thin HfxNy layer on HfO2, followed by reoxidation. This technique resulted in an improved output characteristics compared to the control sample. Leakage current density was significantly reduced by two orders of magnitude. The thermal stability in terms of structural and electrical properties was also enhanced, indicating that the nitrogen-doped process is effective in preventing oxygen diffusion through HfO2. Boron penetration immunity was also improved by nitrogen-incorporation. It is concluded that the nitrogen-incorporation process is a promising technique to obtain high-k dielectric with thin equivalent oxide thickness and good interfacial quality 相似文献
49.
Mudanai S. Li F. Samavedam S.B. Tobin P.J. Kang C.S. Nieh R. Lee J.C. Register L.F. Banerjee S.K. 《Electron Device Letters, IEEE》2002,23(12):728-730
A comprehensive analysis of the bump/kink observed in the experimental capacitance-voltage (C-V) curves of HfO/sub 2/ and ZrO/sub 2/ capacitors was performed using self-consistent numerical simulations. Both HfO/sub 2/ samples grown by sputter deposition and grown by metal-organic chemical vapor deposition (MOCVD) were examined. The bumps in the C-V curves were found to be consistent with an interface state centered 0.25 eV above the valence bandedge for the sputter deposited devices, and 0.30 eV above the bandedge for the MOCVD devices. Annealing of the HfO/sub 2/ devices reduced the densities of these traps, but also increased the effective oxide thickness. Similar defect states were detected for the ZrO/sub 2/ devices centered 0.25 eV above the valence bandedge. 相似文献
50.
Warm-temperature tensile ductility in Al-Mg alloys 总被引:2,自引:0,他引:2
Eric M. Taleff Gregory A. Henshall T. G. Nieh Donald R. Lesuer Jeffrey Wadsworth 《Metallurgical and Materials Transactions A》1998,29(3):1081-1091
Several binary and ternary Al alloys containing from 2.8 to 5.5 wt pct Mg were tested in tension at elevated temperatures
(200 °C to 500 °C) over a range of strain rates (10−4 to 2.0 s−1). Tensile ductilies of up to 325 pct were obtained in binary Al-Mg alloys with coarse grains deformed in the solute-drag
creep regime. Under test conditions in which solute-drag creep controls deformation, Mg in concentrations from 2.8 to 5.5
wt pct neither affects tensile ductility nor influences strain-rate sensitivity or flow stress significantly. Strength is
shown to increase with increasing Mg concentration, however, in the power-law-breakdown regime. The solute-drag creep process,
which leads to superplastic-like elongations, is shown to have no observable grain-size dependence in a binary Al-Mg material.
Ternary alloying additions of Mn and Zr are shown to decrease the strain-rate sensitivity during solute-drag creep, negatively
influencing ductility. An important cause of reduced ductility in the ternary alloys during creep deformation is found to
be a transition from necking-controlled failure in the binary alloys to cavitation-controlled failure in the ternary alloys
investigated. An increase in ternary element concentration, which can increase the relative volume percentage of proeutectic
products, increases cavitation. 相似文献