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91.
A model is presented that describes the wall-to-bed heat transfer in a circulating fluidized bed (CFB) used for the prereduction
of iron ore in the smelting-reduction iron-making process. The model incorporates the core-annulus type flow structure and
the wall emulsion layer growing downward along the surface. Model predictions showed good agreements with measured data taken
from the literature. The hydrodynamic behavior near the wall surface was able to be properly described by the core-annulus
flow structure. A higher heat-transfer coefficient with higher solid circulation flux was obtained in the upper part of the
bed because of the heat input caused by the lateral diffusion of particles from the core. The predicted and measured data
also showed the minima in the heat-transfer coefficients in the lower part of the bed. Model predictions indicated that in
the CFB for the reduction of iron ore particles, it is important to properly control the inlet temperature of the reducing
gas, rather than that of the solid particles. The implications of the behavior of heat transfer in the CFB are discussed for
the reduction of iron oxides. 相似文献
92.
Jyh-Dar Fan L. James Lee Junil Kim Yong-Taek Im 《Polymer Engineering and Science》1989,29(11):740-748
The effects of material flow, heat transfer, part geometry, and curing agents on the cure of sheet molding compounds (SMC) in molds with substructures were analyzed both experimentally and numerically. It was found that heat transfer during mold filling has a profound effect on the cure pattern, especially for fastcure resins molded for parts with thin dimensions. 相似文献
93.
94.
Imène Lahouij Fabrice Dassenoy Ludvig de Knoop Jean-Michel Martin Béatrice Vacher 《Tribology Letters》2011,42(2):133-140
Inorganic fullerene-(IF)-like nanoparticles made of metal dichalcogenides (IF-MoS2, IF-WS2) have been known to be effective as anti-wear and friction modifier additives under boundary lubrication. The lubrication
mechanism of these nanoparticles has been widely investigated in the past and even if the exfoliation and third body transfer
of molecular sheets onto the asperities constitute the prevalent mechanism for the improved tribological behavior of IF nanoparticles,
it has also been suggested that a rolling friction process could also play a role for well crystallized and spherical particles.
In this study, in situ Transmission Electron Microscopy (TEM) observations of the behavior of single IF-MoS2 nanoparticles were conducted using a sample holder that combines TEM and Atomic Force Microscopy (AFM) which simultaneously
can apply normal and shear loads. It was shown that depending on the test conditions, either a rolling process or a sliding
of the fullerenes could be possible. These in situ TEM observations are the first carried out with IF nanoparticles. 相似文献
95.
96.
A PbS-sensitized photovoltaic photodetector responsive to near-infrared (NIR) light was fabricated by depositing monolayered PbS nanoparticles on a mesoporous TiO(2) (mp-TiO(2)) film via the spin-assisted successive ionic layer adsorption and reaction (SILAR) method. By adjusting the size and morphology of the PbS nanoparticles through repeated spin-assisted SILAR cycles, the PbS-sensitized photovoltaic photodetector achieved an external quantum efficiency of 9.3% at 1140 nm wavelength and could process signals up to 1 kHz. 相似文献
97.
Ad hoc networks have a scalability problem. When the nodes of an ad hoc network increase in number or mobility, the amount
of control traffic for routing increases and could cause traffic congestion. Cluster-based routing schemes have been proposed
as a solution to this problem. Typical cluster-based ad hoc networks use a proactive routing scheme for intra-cluster routes
and a reactive routing scheme for inter-cluster routes. In this study, we propose a new cluster-based routing scheme for ad
hoc networks which makes use of the mobility of nodes. Nodes are divided into two groups on the basis of their mobility. For
a route search within a cluster, a proactive routing scheme is used for low-mobility nodes and a flooding-based reactive routing
scheme is used for high-mobility nodes. The required control traffic of the proposed scheme is analyzed and optimal parameters
of the proposed scheme are derived from the analysis. The numerical results show that the proposed scheme produces far less
control traffic than a typical cluster-based routing scheme. 相似文献
98.
Donghyun Kim Jaewook Jeong Hwarim Im Sungmo Ahn Heonsu Jeon Changhee Lee Yongtaek Hong 《Organic Electronics》2011,12(11):1841-1845
Vertical organic field-effect transistors (VOFETs) with nanoscale channel openings have been fabricated using pentacene as an active layer material. To achieve uniform nanoscale two-dimensional channel openings, a laser holography lithography has been introduced. Uniformly distributed and well-aligned holes with 250 nm diameter were successfully obtained with the laser holography lithography. VOFET devices with these channel openings have shown high on/off ratio of about 103 without any further treatment. Gate leakage current was also decreased with an additional insulating layer generated on the gate electrode sidewall via plasma oxidation. 相似文献
99.
Distributed Virtual Inertia Based Control of Multiple Photovoltaic Systems in Autonomous Microgrid 下载免费PDF全文
Won-Sang Im Cheng Wang Wenxin Liu Liming Liu Jang-Mok Kim 《IEEE/CAA Journal of Automatica Sinica》2017,4(3):512-519
The large inertia of a traditional power system slows down system's frequency response but also allows decent time for controlling the system. Since an autonomous renewable microgrid usually has much smaller inertia, the control system must be very fast and accurate to fight against the small inertia and uncertainties. To reduce the demanding requirements on control, this paper proposes to increase the inertia of photovoltaic (PV) system through inertia emulation. The inertia emulation is realized by controlling the charging/discharging of the direct current (DC)-link capacitor over a certain range and adjusting the PV generation when it is feasible and/or necessary. By well designing the inertia, the DC-link capacitor parameters and the control range, the negative impact of inertia emulation on energy efficiency can be reduced. The proposed algorithm can be integrated with distributed generation setting algorithms to improve dynamic performance and lower implementation requirements. Simulation studies demonstrate the effectiveness of the proposed solution. 相似文献
100.