731 research outputs found
Electric Character of Strange Stars
Using the Thomas-Fermi model, we investigated the electric characteristics of
a static non-magnetized strange star without crust in this paper. The exact
solutions of electron number density and electric field above the quark surface
are obtained. These results are useful if we are concerned about physical
processes near the quark matter surfaces of strange stars.Comment: 4 pages, 2 figures, LaTeX, Published in Chinese Physics Letters,
Vol.16, p.77
Functional characterization of a short peptidoglycan recognition protein from Chinese giant salamander (Andrias davidianus)
This work was supported by the National Natural Science Foundation of China (Grant no. 31302221, 31172408 and 31272666) and Jiangsu Province (Grant no. BK20171274 and BK2011418), and partially by the Opening Project of Jiangsu Key Laboratory of Biochemistry and Biotechnology of Marine Wetland (Grant no. K2016-08). QZ was supported by the âQinglanâ project of Jiangsu province of China.Peer reviewedPublisher PD
Nearby SNR: a possible common origin to multi-messenger anomalies in spectra, ratios and anisotropy of cosmic rays
The multi-messenger anomalies, including spectral hardening or excess for
nuclei, leptons, ratios of and B/C, and anisotropic reversal, were
observed in past years. AMS-02 experiment also revealed different spectral
break for positron and electron at 284 GeV and beyond TeV respectively. It is
natural to ask whether all those anomalies originate from one unified physical
scenario. In this work, the spatially-dependent propagation (SDP) with a nearby
SNR source is adopted to reproduce above mentioned anomalies. There possibly
exists dense molecular cloud(DMC) around SNRs and the secondary particles can
be produced by pp-collision or fragmentation between the accelerated primary
cosmic rays and DMC. As a result, the spectral hardening for primary, secondary
particles and ratios of and can be well reproduced. Due to the
energy loss at source age of 330 kyrs, the characteristic spectral break-off
for primary electron is at about 1 TeV hinted from the measurements. The
secondary positron and electron from charged pion take up energy from
their mother particles, so the positron spectrum has a cut-off at 250
GeV. Therefore, the different spectral break for positron and electron together
with other anomalies can be fulfilled in this unified physical scenario. More
interesting is that we also obtain the featured structures as spectral
break-off at 5 TV for secondary particles of Li, Be, B, which can be served to
verify our model. We hope that those tagged structures can be observed by the
new generation of space-borne experiment HERD in future.Comment: 16 pages, 12 figure
Monopole-charged pulsars and relevant issues
The aligned pulsars whose rotation axes and magnetic dipole axes are parallel
should be positively charged. The total charge of pulsars is calculated after
considering the electromagnetic field in and out the star under a specific
condition. The statistical relation between the pulsar's rotation energy loss
rate (or the period derivative) and the period may hint that the millisecond
radio pulsars with small periods could be low-mass bare strange stars.Comment: 4 pages, 1 figures, and 1 tabl
5 GHz TMRT observations of 71 pulsars
We present integrated pulse profiles at 5~GHz for 71 pulsars, including eight
millisecond pulsars (MSPs), obtained using the Shanghai Tian Ma Radio Telescope
(TMRT). Mean flux densities and pulse widths are measured. For 19 normal
pulsars and one MSP, these are the first detections at 5~GHz and for a further
19, including five MPSs, the profiles have a better signal-to-noise ratio than
previous observations. Mean flux density spectra between 400~MHz and 9~GHz are
presented for 27 pulsars and correlations of power-law spectral index are found
with characteristic age, radio pseudo-luminosity and spin-down luminosity. Mode
changing was detected in five pulsars. The separation between the main pulse
and interpulse is shown to be frequency independent for six pulsars but a
frequency dependence of the relative intensity of the main pulse and interpulse
is found. The frequency dependence of component separations is investigated for
20 pulsars and three groups are found: in seven cases the separation between
the outmost leading and trailing components decreases with frequency, roughly
in agreement with radius-to-frequency mapping; in eleven cases the separation
is nearly constant; in the remain two cases the separation between the outmost
components increases with frequency. We obtain the correlations of pulse widths
with pulsar period and estimate the core widths of 23 multi-component profiles
and conal widths of 17 multi-component profiles at 5.0~GHz using Gaussian
fitting and discuss the width-period relationship at 5~GHz compared with the
results at at 1.0~GHz and 8.6~GHz.Comment: 46 pages, 14 figures, 8 Tables, accepted by Ap
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