No abstract

A passive radiative cooling method has a significant influence on thermal management applications because it can cool without any energy input. This work both experimentally and theoretically demonstrates a multilayer thin film structure with high solar reflectance, which can be applied to passive daytime radiative cooling. The combination of physical vapor deposition and spin-coating prepared the samples, which were also characterized experimentally by spectrometers. On-site measured results show that the emitter can effectively achieve daytime radiative cooling, and the cooling performance can be further improved with the increase of the ambient air temperature. When the emitter is exposed to direct solar radiation (AM1.5) of about 880 W/m2 on a rooftop under dry air conditions, it can achieve an average temperature reduction of about 12.6 °C from the ambient air temperature with nonradiative heat transfer (11 a.m.–1 p.m.). Theoretical simulations reveal that the emitter can still have a certain cooling performance in the presence of significant nonradiative heat exchange and nonideal atmospheric conditions. The influence of ambient air temperature on the cooling performance of the emitter is also theoretically analyzed.

Hyperloop is envisioned as a novel transportation way with merits of ultra-high velocity and great traveling comforts. In this paper, we present some concepts on the key technologies dedicated to the train-to-ground communication system based on some prevailing fifth-generation communication (5G) technologies from three aspects: wireless channel, network architecture, and resource management. First, we characterize the wireless channel of the distributed antenna system (DAS) using the propagation-graph channel modelling theory. Simulation reveals that a drastic Doppler shift variation appears when crossing the trackside antenna. Hence, the leaky waveguide system is a promising way to provide a stable receiving signal. In this regard, the radio coverage is briefly estimated. Second, a cloud architecture is utilized to integrate several successive trackside leaky waveguides into a logical cell to reduce the handover frequency. Moreover, based on a many-to-many mapping relationship between distributed units (DUs) and centralized units (CUs), a novel access network architecture is proposed to reduce the inevitable handover cost by using the graph theory. Simulation results show that this scheme can yield a low handover cost. Then, with regards to the ultra-reliable and low latency communication (uRLLC) traffic, a physical resource block (PRB) multiplexing scheme considering the latency requirements of each traffic type is exploited. Simulation presents that this scheme can maximize the throughput of non-critical mission communication services while guaranteeing the requirements of uRLLC traffic. Finally, in terms of the non-critical mission communication services, two cache-based resource management strategies are proposed to boost the throughput and reduce the midhaul link burden by pre-fetching and post-uploading schemes. Simulation demonstrates that the cache-based schemes can boost the throughput dramatically.

This work theoretically demonstrates a quasi-periodic selective multilayer emitter for sub-ambient daytime radiative cooling. In the design process, by inserting well-defined materials with different refractive-index profiles in suitable layers, there are absorption bands at different regions and the absorption bands are enhanced and broad in atmospheric transparency windows. Combined with the interference effects of the surface and the high reflectivity of Ag, the solar reflectance of the emitter is maximal in the solar spectrum. The influence of different nonradiative heat exchanges and the ambient air temperatures on the cooling performance of the multilayer emitter are calculated. At the same time, the mechanism of radiative cooling is analyzed. All the results show that the proposed emitter can effectively achieve sub-ambient daytime radiative cooling. Due to the superior durability and mechanical robustness of the multilayer emitter, it may be a key element in the realization of energy-efficient radiative cooling devices.

The zinc complex of 3,5-di-tert-butyl salicylate (Zn{[CH3)3C]2Sal}22−) is a zinc ion chelate of salicylate. In this study, we found that this compound inhibits viability, invasion, and migration and induces apoptosis in triple-negative breast cancer 4T1 cells. RNA-seq showed that the expression of 17 genes was upregulated and 26 genes were downregulated significantly by Zn{[CH3)3C]2Sal}22− treatment. Further GO and KEGG analysis showed that the activity of Zn{[CH3)3C]2Sal}22− against triple-negative breast cancer cells may be involved in the JAK-STAT3, HIF-1, and TNF signaling pathways. The expression of key genes was verified by RT–PCR. The phosphorylation of STAT3 and its upstream SRC decreased drastically upon Zn{[CH3)3C]2Sal}22− treatment, as demonstrated by western blot. Our results indicate that Zn{[CH3)3C]2Sal}22− inhibits the activity of TNBC cells by downregulating the STAT3 signaling through the SRC pathway.