10,186 research outputs found
Asian Dust Storm as a Natural Source of Air Pollution in East Asia; its Nature, Aging and Extinction
Dark information of black hole radiation raised by dark energy
The "lost" information of black hole through the Hawking radiation was
discovered being stored in the correlation among the non-thermally radiated
particles [Phys. Rev. Lett 85, 5042 (2000), Phys. Lett. B 675, 1 (2009)]. This
correlation information, which has not yet been proved locally observable in
principle, is named by dark information. In this paper, we systematically study
the influences of dark energy on black hole radiation, especially on the dark
information. Calculating the radiation spectrum in the existence of dark energy
by the approach of canonical typicality, which is reconfirmed by the quantum
tunneling method, we find that the dark energy will effectively lower the
Hawking temperature, and thus makes the black hole has longer life time. It is
also discovered that the non-thermal effect of the black hole radiation is
enhanced by dark energy so that the dark information of the radiation is
increased. Our observation shows that, besides the mechanical effect (e.g.,
gravitational lensing effect), the dark energy rises the the stored dark
information, which could be probed by a non-local coincidence measurement
similar to the coincidence counting of the Hanbury-Brown -Twiss experiment in
quantum optics.Comment: 21 pages, 3 figures, complete journal-info of Ref.[4] is added,
comments are welcome ([email protected]
The Chemical Nature of Individual Size-Resolved Raindrops and Their Residual Particles Collected During High Atmospheric Loading for PM<sub>2.5</sub>
Although it is well known that rain plays an important role in capturing air pollutants, its quantitative evaluation has not been done enough. In this study, the pollutant scavenging effect by size of raindrops was investigated by clarifying the chemical nature of individual size-resolved raindrops and their residual particles. Raindrops as a function of their size were collected using the raindrop collector devised by ourselves during high atmospheric loading for PM2.5. The raindrop number concentration (m−2 h−1) tended to drastically decrease as the drop size goes up. Particle scavenging rate, Rsca.(%), based on the actual measurement values were 38.7, 69.5, and 80.8% for the particles with 0.3–0.5, 0.5–1.0, and 1.0–2.0 μm diameter, respectively. S, Ca, Si, and Al ranked relatively high concentration in raindrops, especially small ones. Most of the element showed a continuous decrease in concentration with increasing raindrop diameter. The source profile by factor analysis for the components of residual particles indicated that the rainfall plays a valuable role in scavenging natural as well as artificial particles from the dirty atmosphere
Improving the Performance of R17 Type-II Codebook with Deep Learning
The Type-II codebook in Release 17 (R17) exploits the angular-delay-domain
partial reciprocity between uplink and downlink channels to select part of
angular-delay-domain ports for measuring and feeding back the downlink channel
state information (CSI), where the performance of existing deep learning
enhanced CSI feedback methods is limited due to the deficiency of sparse
structures. To address this issue, we propose two new perspectives of adopting
deep learning to improve the R17 Type-II codebook. Firstly, considering the low
signal-to-noise ratio of uplink channels, deep learning is utilized to
accurately select the dominant angular-delay-domain ports, where the focal loss
is harnessed to solve the class imbalance problem. Secondly, we propose to
adopt deep learning to reconstruct the downlink CSI based on the feedback of
the R17 Type-II codebook at the base station, where the information of sparse
structures can be effectively leveraged. Besides, a weighted shortcut module is
designed to facilitate the accurate reconstruction. Simulation results
demonstrate that our proposed methods could improve the sum rate performance
compared with its traditional R17 Type-II codebook and deep learning
benchmarks.Comment: Accepted by IEEE GLOBECOM 2023, conference version of
Arxiv:2305.0808
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