Non-condensable gas (NCG) is one of the main causes affecting the thermal performance and lifespan of the two-phase heat transfer devices. In this work, the effect of NCG on the operating performance of an ammonia-stainless steel loop heat pipe (LHP) was experimentally investigated. Nitrogen was selected as NCG, and the steady-state operating characteristics of the LHP with NCG was systematically studied for different NCG inventories, heat loads applied to the evaporator, heat load cycles and heat sink temperatures. Experimental results reveal that NCG elevates the operating temperature of the evaporator, and the more NCG exists, the higher the operating temperature of the evaporator and the larger the heat load range corresponding to the variable conductance mode. Meanwhile, the effect of NCG is notable for a smaller heat load or lower heat sink temperature. The increase of the operating temperature attributes to that NCG breaks the original energy/pressure balance of the components of the LHP, which leads to further change of heat and mass transfer as well as the redistribution of the working fluid in the loop. With NCG in the LHP, the temperature hysteresis is a common phenomenon for different heat load cycles. In addition, unique temperature oscillation was observed in the experiments, and it may be associated with the frequent repeated processes of the generation/collapse of the bubbles in the evaporator core. (C) 2013 Elsevier Ltd. All rights reserved.
Clusters are important drivers of regional economic growth. Although their benefits are well recognized, research into their evolution is still ongoing. Most real-world clusters seem to have emerged spontaneously without deliberate policy interventions, each cluster having its own evolutionary path. Since there is a significant gap in our understanding of the forces driving their evolution, this study uses a quantitative approach to investigate the role of inventor collaboration networks in it. Inventor collaboration networks for 30 top-performing American metropolitan clusters were constructed on the basis of patent co-authorship data. The selected clusters operate in hi-tech fields: information technology, communications equipment and the biopharmaceutical industry. Starting from a widely accepted hypothesis that the 'small-world' structure is an optimal one for knowledge spillovers and promotes innovation effectively, the authors statistically tested the impact of 'small-world' network properties on cluster innovation performance proxied by patent output. The results suggest that the effect of the small-world structure is not as significant as theorists hypothesized, not all clusters benefit from the presence of inventor collaboration networks, and cluster performance can be affected by policy interventions. Our analyses also suggest that cluster typology moderates the impact of inventor network properties on cluster innovation performance.
Disclosed are a self-focusing lens thermopile sensor and an assembly process thereof. The self-focusing lens thermopile sensor comprises a body (1) having a through hole, an infrared lens (2) fixedly arranged at the through hole of the body (1) transmissive to infrared light, and a sensing unit (3) arranged in the body (1) for sensing the infrared light focused by the infrared lens (2). Such a self-focusing lens thermopile sensor is integrated with the functions of infrared light transmission and focusing. After an infrared lens (2) transmissive to infrared light is arranged on a surface, infrared light is focused onto a sensing unit (3). Since there is only one lens, the transmittance of infrared light is increased; moreover, the infrared lens (2) can be made into a size as that of the sensor, reducing the size of the self-focusing lens thermopile sensor, thus reducing the costs, and simply and practically achieving the purpose of relatively long distance precise detection.
Bujny, Miriam V.
Davidson, Michael W.
Barclay, Wendy S.
As an obligatory pathogen, influenza virus co-opts host cell machinery to harbor infection and to produce progeny viruses. In order to characterize the virus-host cell interactions, several genome-wide siRNA screens and proteomic analyses have been performed recently to identify host factors involved in influenza virus infection. CD81 has emerged as one of the top candidates in two siRNA screens and one proteomic study. The exact role played by CD81 in influenza infection, however, has not been elucidated thus far. In this work, we examined the effect of CD81 depletion on the major steps of the influenza infection. We found that CD81 primarily affected virus infection at two stages: viral uncoating during entry and virus budding. CD81 marked a specific endosomal population and about half of the fused influenza virus particles underwent fusion within the CD81-positive endosomes. Depletion of CD81 resulted in a substantial defect in viral fusion and infection. During virus assembly, CD81 was recruited to virus budding site on the plasma membrane, and in particular, to specific subviral locations. For spherical and slightly elongated influenza virus, CD81 was localized at both the growing tip and the budding neck of the progeny viruses. CD81 knockdown led to a budding defect and resulted in elongated budding virions with a higher propensity to remain attached to the plasma membrane. Progeny virus production was markedly reduced in CD81-knockdown cells even when the uncoating defect was compensated. In filamentous virus, CD81 was distributed at multiple sites along the viral filament. Taken together, these results demonstrate important roles of CD81 in both entry and budding stages of the influenza infection cycle.