204 research outputs found
Mobile charging and data gathering in multiple sink wireless sensor networks: how and why
Recently, the problem of using efficient the number of mobile devices starting from multi-sink to go to charge and collect data of sensors such that sensors can work forever has received a great deal of attention in Wireless Rechargeable Sensor Network (WRSN). Many methods have been proposed for the WRSN systems such that mobile device can charge and collect data from sensors. However, most of previous works often require lots of mobile devices while the cost of mobile device is very high. In this paper, we investigate the Periodic Energy Replenishment and Data Collection with multiple sink (PERDCMS) problem and propose a new algorithm, called the Mobile Device Scheduling Algorithm (MDSA), to using limited number of mobile devices for charging and collecting data for sensors. Simulation results show that the MDSA has better performance than other method
Site-specific incorporation of phosphotyrosine using an expanded genetic code.
Access to phosphoproteins with stoichiometric and site-specific phosphorylation status is key to understanding the role of protein phosphorylation. Here we report an efficient method to generate pure, active phosphotyrosine-containing proteins by genetically encoding a stable phosphotyrosine analog that is convertible to native phosphotyrosine. We demonstrate its general compatibility with proteins of various sizes, phosphotyrosine sites and functions, and reveal a possible role of tyrosine phosphorylation in negative regulation of ubiquitination
Corrigendum: Revealing the mechanism of Huazhi Rougan granule in the treatment of nonalcoholic fatty liver through intestinal flora based on 16S rRNA, metagenomic sequencing and network pharmacology
Graphical Abstrac
An Updated Search of Steady TeV Ray Point Sources in Northern Hemisphere Using the Tibet Air Shower Array
Using the data taken from Tibet II High Density (HD) Array (1997
February-1999 September) and Tibet-III array (1999 November-2005 November), our
previous northern sky survey for TeV ray point sources has now been
updated by a factor of 2.8 improved statistics. From to
in declination (Dec) range, no new TeV ray point
sources with sufficiently high significance were identified while the
well-known Crab Nebula and Mrk421 remain to be the brightest TeV ray
sources within the field of view of the Tibet air shower array. Based on the
currently available data and at the 90% confidence level (C.L.), the flux upper
limits for different power law index assumption are re-derived, which are
approximately improved by 1.7 times as compared with our previous reported
limits.Comment: This paper has been accepted by hepn
Observation of GRB 221009A early afterglow in X/-ray energy band
The early afterglow of a Gamma-ray burst (GRB) can provide critical
information on the jet and progenitor of the GRB. The extreme brightness of GRB
221009A allows us to probe its early afterglow in unprecedented detail. In this
letter, we report comprehensive observation results of the early afterglow of
GRB 221009A (from +660 s to +1860 s, where is the
\textit{Insight}-HXMT/HE trigger time) in X/-ray energy band (from 20
keV to 20 MeV) by \textit{Insight}-HXMT/HE, GECAM-C and \textit{Fermi}/GBM. We
find that the spectrum of the early afterglow in 20 keV-20 MeV could be well
described by a cutoff power-law with an extra power-law which dominates the low
and high energy bands respectively. The cutoff power-law is
30 keV and the power-law photon index is 1.8 throughout the early
afterglow phase. By fitting the light curves in different energy bands, we find
that a significant achromatic break (from keV to TeV) is required at +
1246 s (i.e. 1021 s since the afterglow starting time =+225 s), providing compelling evidence of a jet break. Interestingly,
both the pre-break and post-break decay slopes vary with energy, and these two
slopes become closer in the lower energy band, making the break less
identifiable. Intriguingly, the spectrum of the early afterglow experienced a
slight hardening before the break and a softening after the break. These
results provide new insights into the understanding of this remarkable GRB.Comment: Accepted for publication in ApJ Letters on 19-Jan-2024, 11 pages, 7
figures and 2 table
Ground calibration of Gamma-Ray Detectors of GECAM-C
As a new member of GECAM mission, GECAM-C (also named High Energy Burst
Searcher, HEBS) was launched onboard the SATech-01 satellite on July 27th,
2022, which is capable to monitor gamma-ray transients from 6 keV to 6
MeV. As the main detector, there are 12 gamma-ray detectors (GRDs) equipped for
GECAM-C. In order to verify the GECAM-C GRD detector performance and to
validate the Monte Carlo simulations of detector response, comprehensive
on-ground calibration experiments have been performed using X-ray beam and
radioactive sources, including Energy-Channel relation, energy resolution,
detection efficiency, SiPM voltage-gain relation and the non-uniformity of
positional response. In this paper, the detailed calibration campaigns and data
analysis results for GECAM-C GRDs are presented, demonstrating the excellent
performance of GECAM-C GRD detectors.Comment: third versio
Synchrotron Radiation Dominates the Extremely Bright GRB 221009A
The brightest Gamma-ray burst, GRB 221009A, has spurred numerous theoretical
investigations, with particular attention paid to the origins of ultra-high
energy TeV photons during the prompt phase. However, analyzing the mechanism of
radiation of photons in the MeV range has been difficult because the high
flux causes pile-up and saturation effects in most GRB detectors. In this
letter, we present systematic modeling of the time-resolved spectra of the GRB
using unsaturated data obtained from Fermi/GBM (precursor) and
SATech-01/GECAM-C (main emission and flare). Our approach incorporates the
synchrotron radiation model, which assumes an expanding emission region with
relativistic speed and a global magnetic field that decays with radius, and
successfully fits such a model to the observational data. Our results indicate
that the spectra of the burst are fully in accordance with a synchrotron origin
from relativistic electrons accelerated at a large emission radius. The lack of
thermal emission in the prompt emission spectra supports a
Poynting-flux-dominated jet composition.Comment: 12 pages, 6 figures, 2 tables. Accepted for publication in ApJ
Calibration of the Timing Performance of GECAM-C
As a new member of the Gravitational wave high-energy Electromagnetic
Counterpart All-sky Monitor (GECAM) after GECAM-A and GECAM-B, GECAM-C
(originally called HEBS), which was launched on board the SATech-01 satellite
on July 27, 2022, aims to monitor and localize X-ray and gamma-ray transients
from 6 keV to 6 MeV. GECAM-C utilizes a similar design to GECAM but
operates in a more complex orbital environment. In this work, we utilize the
secondary particles simultaneously produced by the cosmic-ray events on orbit
and recorded by multiple detectors, to calibrate the relative timing accuracy
between all detectors of GECAM-C. We find the result is 0.1 , which
is the highest time resolution among all GRB detectors ever flown and very
helpful in timing analyses such as minimum variable timescale and spectral
lags, as well as in time delay localization. Besides, we calibrate the absolute
time accuracy using the one-year Crab pulsar data observed by GECAM-C and
Fermi/GBM, as well as GECAM-C and GECAM-B. The results are and , respectively. Finally, we investigate the
spectral lag between the different energy bands of Crab pulsar observed by
GECAM and GBM, which is .Comment: submitte
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