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991.
A novel hybrid carbon material 总被引：2，自引：0，他引：2
Nasibulin AG Pikhitsa PV Jiang H Brown DP Krasheninnikov AV Anisimov AS Queipo P Moisala A Gonzalez D Lientschnig G Hassanien A Shandakov SD Lolli G Resasco DE Choi M Tománek D Kauppinen EI 《Nature nanotechnology》2007,2(3):156-161
Both fullerenes and single-walled carbon nanotubes (SWNTs) exhibit many advantageous properties. Despite the similarities between these two forms of carbon, there have been very few attempts to physically merge them. We have discovered a novel hybrid material that combines fullerenes and SWNTs into a single structure in which the fullerenes are covalently bonded to the outer surface of the SWNTs. These fullerene-functionalized SWNTs, which we have termed NanoBuds, were selectively synthesized in two different one-step continuous methods, during which fullerenes were formed on iron-catalyst particles together with SWNTs during CO disproportionation. The field-emission characteristics of NanoBuds suggest that they may possess advantageous properties compared with single-walled nanotubes or fullerenes alone, or in their non-bonded configurations. 相似文献
992.
This paper presents the fabrication of self-folding devices with minimal human intervention. The devices utilize two easily obtainable and commercially available materials, namely, PVC shrink wrap (contraction layer) and copper foil tape (structural layer). The selffolding structure uses predefined crease patterns to create mountain and valley folds when subjected to a temperature change (67 °C to 91 °C). A unique crease pattern is designed through defined gap widths to act as hinges. The fabrication technique involves a rapid prototyping methodology that employs low-cost materials. The rapid and efficient manufacturing of the self-folding assembly has an advantage over other fabrication techniques that require numerous layers and complex manufacturing steps. As a result, the self-folding technology in this study achieves the 3D transformation of a cubic and pyramid structure from a 2D framework. 相似文献
993.
Vladimir V. Dmitriev David E. Crowley Anton N. Zvonarev Tatiana G. Rusakova Maria C. Negri Svetlana A. Kolesnikova 《Yeast (Chichester, England)》2016,33(2):55-62
Electron‐microscopic examinations have demonstrated local modifications in the cell wall of the yeast Candida maltosa grown on hexadecane. In our earlier studies, these modified sites, observed in other yeasts grown on oil hydrocarbons, were conventionally called 'canals'. The biochemical and cytochemical studies of C. maltosa have revealed a correlation between the formation of 'canals' and decrease in the amount of cell wall polysaccharides, glucan and mannan. The ultrathin sections and surface replicas have shown that the 'canals' are destroyed by pronase, thus indicating that a significant proportion of their content is represented by proteins. This finding was compatible with our earlier data on the localization of oxidative enzymes in 'canals' and possible participation of the 'canals' in the primary oxidation of hydrocarbons. A completely unexpected and intriguing phenomenon has been the appearance of 'canals' in the yeast C. maltosa under starvation conditions. Unlike the yeasts grown on hexadecane, mannan almost disappears in starving cells, while the quantity of glucan first decreases and then is restored to its initial level. The role of 'canals' in starving cells is as yet unclear; it is assumed that they acquire exoenzymes involved in the utilization of products of cell lysis in the starving population. In the future, 'canals' of starving cells will be studied in connection with their possible participation in apoptosis. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
994.
Shuyan Shao Mustapha Abdu‐Aguye Tejas S. Sherkar Hong‐Hua Fang Sampson Adjokatse Gert ten Brink Bart J. Kooi L. Jan Anton Koster Maria Antonietta Loi 《Advanced functional materials》2016,26(44):8094-8102
Despite the rich experience gained in controlling the microstructure of perovskite films over the past several years, little is known about how the microstructure affects the device properties of perovskite solar cells (HPSCs). In this work, the effects of the perovskite film microstructure on the charge recombination and light‐soaking phenomenon in mixed halide HPSCs are investigated. Devices with noncompact perovskite morphology show a severe light soaking effect, with the power conversion efficiency (PCE) improved from 3.7% to 11.6% after light soaking. Devices with compact perovskite morphology show a negligible light soaking effect, with PCE slightly increased from 11.4% to 11.9% after light soaking. From device investigations, photoluminescence, and impedance spectroscopy measurements, it is demonstrated that interface electron traps at the grain boundaries as well as at the crystal surface dominate the light soaking effect. Severe trap‐assisted recombination takes place in HPSCs using noncompact films, while it is effectively eliminated in devices with compact films. Moreover, how the grain size of the perovskite film affects the light soaking phenomenon is investigated. In the case of compact perovskite films, the size of the grains has a limited effect on the light soaking. In these compact films, grains are fused and trap states are effectively reduced. 相似文献
995.
We consider almost output synchronization for directed heterogeneous time‐varying networks where agents are non‐introspective (i.e., agents have no access to their own states or outputs) in the presence of external disturbances. The nonlinear agents have a triangular structure and are globally Lipschitz continuous. The network can be time‐varying with network switches occurring at arbitrary moments. A purely decentralized time‐invariant protocol based on a low‐gain and high‐gain method is designed for each agent to achieve almost output synchronization while reducing the impact of disturbances on the output synchronization error. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
996.
Johanna Rousson Patrick De Visschere Anton Vasiliev Arnout Vetsuypens Tom Kimpe 《Journal of the Society for Information Display》2016,24(7):454-464
The tendency of the display market is towards displays with higher resolutions. Therefore, patterned retarder‐based stereoscopic displays require smaller front glass thickness to maintain good vertical viewing angle and limited crosstalk. To properly design these stereoscopic displays and quantify these requirements, we developed a simulation platform to predict radiance, polarization profile, and crosstalk over viewing angles and over wavelengths. Tunable parameters such as the distance between the pixels and the patterned retarder, and the optical properties of the patterned retarder are included. The simulation platform has been validated by comparing outcomes of simulations with measurements. We predict crosstalk accounting for both the human eye field of view and the diameter of the pupil. We found that to obtain a vertical viewing angle of at least ± 30° and crosstalk of at most 0.11 for a display with a pixel pitch beyond 0.27 mm, the display should include black absorbers, and the thickness of the front glass should be at most 0.5 mm. For higher resolution displays (pixel pitch no more than 0.21 mm), a front glass thickness at most 0.15 mm is required to produce a vertical viewing angle beyond ± 14° and a minimum viewing distance of 0.3 m. 相似文献
997.
Sergey Guminov Alexander Gasnikov Anton Anikin Alexander Gornov 《Optimization methods & software》2019,34(3):560-577
In the late sixties, N. Shor and B. Polyak independently proposed optimal first-order methods for solving non-smooth convex optimization problems. In 1982 A. Nemirovski proposed optimal first-order methods for solving smooth convex optimization problems, which utilized auxiliary line search. In 1985 A. Nemirovski and Yu. Nesterov proposed a parametric family of optimal first-order methods for solving convex optimization problems with intermediate smoothness. In 2013 Yu. Nesterov proposed a universal gradient method which combined all good properties of the previous methods, except the possibility of using auxiliary line search. One can typically observe that in practice auxiliary line search improves performance for many tasks. In this paper, we propose the apparently first such method of non-smooth convex optimization allowing the use of the line search procedure. Moreover, it is based on the universal gradient method, which does not require any a priori information about the actual degree of smoothness of the problem. Numerical experiments demonstrate that the proposed method is, in some cases, considerably faster than Nesterov's universal gradient method. 相似文献
998.
This paper studies state synchronization of homogeneous multiagent systems (MAS) via a static protocol with partial‐state coupling in the presence of a time‐varying communication topology, which includes general time‐varying graphs as well as switching graphs. If the agents are squared‐down passive or squared‐down passifiable (via static output feedback or static input feedforward), then a static protocol can be designed for balanced, time‐varying graphs. Moreover, this static protocol works for arbitrary switching directed graphs if the agents are squared‐down minimum phase with relative degree one. The static protocol is designed for each agent such that state synchronization is achieved without requiring exact knowledge about the time‐varying network. 相似文献
999.
This paper studies H2 and H∞ almost output synchronization problems for heterogeneous continuous‐time multiagent systems with passive agents and strongly connected communication graph. For non‐introspective passive agents, a linear static protocol can be designed to achieve almost output synchronization with arbitrarily small H2 norm. Moreover, we show that the H∞ almost output synchronization problem via static protocol is not solvable for this class of systems. 相似文献
1000.
Technostress—defined as stress that individuals experience due to their use of Information Systems—represents an emerging phenomenon of scholarly investigation. It examines how and why the use of IS causes individuals to experience various demands that they find stressful. This paper develops a framework for guiding future research in technostress experienced by individuals in organizations. We first review and critically analyse the state of current research on technostress reported in journals from the IS discipline and the non‐IS disciplines that study stress in organizations (eg, organizational behaviour and psychological stress). We then develop our framework in the form of the “technostress trifecta”—techno‐eustress, techno‐distress, and Information Systems design principles for technostress. The paper challenges 3 key ideas imbued in the existing technostress literature. First, it develops the argument that, in contrast to negative outcomes, technostress can lead to positive outcomes such as greater effectiveness and innovation at work. Second, it suggests that instead of limiting the role of IS to that of being a stress creator in the technostress phenomenon, it should be expanded to that of enhancing the positive and mitigating the negative effects of technostress through appropriate design. Third, it lays the groundwork for guiding future research in technostress through an interdisciplinary framing that enriches both the IS and the psychological stress literatures through a potential discourse of disciplinary exchange. 相似文献