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Effects of supply air temperature and inlet location on particle dispersion in displacement ventilation rooms 总被引:1,自引:0,他引:1
The effects of supply temperature and vertical location of inlet air on particle dispersion in a displacement ventilated (DV) room were numerically modeled with validation by experimental data from the literature. The results indicate that the temperature and vertical location of inlet supply air did not greatly affect the air distribution in the upper parts of a DV room, but could significantly influence the airflow pattern in the lower parts of the room, thus affecting the indoor air quality with contaminant sources located at the lower level, such as particles from working activities in an office. The numerical results also show that the inlet location would slightly influence the relative ventilation efficiency for the same air supply volume, but particle concentration in the breathing zone would be slightly lower with a low horizontal wall slot than a rectangular diffuser. Comparison of the results for two different supply temperatures in a DV room shows that, although lower supply temperature means less incoming air volume, since the indoor flow is mainly driven by buoyancy, lower supply temperature air could more efficiently remove passive sources (such as particles released from work activities in an office). However, in the breathing zone it gives higher concentration as compared to higher supply air temperature. To obtain good indoor air quality, low supply air temperature should be avoided because concentration in the breathing zone has a stronger and more direct impact on human health. 相似文献
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Ion implantation technique is used to study the magnetic properties of Cu-dopecl ZnO. The room temperature ferromagnetism in the Cu-implanted ZnO samples is observed. From the photoluminescence spectrum of implanted samples we observe a broad green emission around 510nm, which is related to defects in the samples. X-ray photoelectron spectroscopy measurement shows that Cu ions are in the mixed oxidation state of 4-1 or +2 and substitute for the Zn^2+ ions of the ZnO matrix. We argue that the ferromagnetism is related to these defects, and the substitution of Cu^2+ into Zn^2+ sites in crystal ZnO could contribute to the observed ferromagnetism. 相似文献
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A room division multiplexing(RDM)-based hybrid visible light communication(VLC) network for realizing indoor broadband communication within a multi-room house is presented.The downlink information is transmitted by light-emitting diode lamps,whereas the uplink information is transmitted through WiFi.RDM is introduced to improve the VLC network throughput;in addition,the associated signaling localization and active handoff mechanisms are designed for implementation.The experimental platform demonstrates the effectiveness of the proposed hybrid architecture,along with the RDM and active handoff mechanisms. 相似文献
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