Abstract
We report the timing and spectral analyses of the type-II X-ray bursts from the rapid burster (MXB 1730–335) observed by the Hard X-ray Modulation Telescope (Insight-HXMT) and Swift/X-Ray ...Telescope (XRT). By stacking the long-duration bursts, we find for the first time that the hard X-rays are lagging behind the soft X-rays by 3 s. However, such a lag is not visible for the short-duration bursts, probably because of the poor statistics. For all bursts the energy spectrum is found to be nonthermal, thanks to the broadband coverage of Insight-HXMT. These findings provide new insights into the type-II bursts and require a temporally visible corona for possible interpretation.
The iron-pnictide superconductors have a layered structureformed by stacks of FeAs planes from which the superconductivity originates. Given the multiband and quasi three-dimensional (3D) electronic ...structure of these high-temperature superconductors, knowledge of the quasi-3D superconducting (SC) gap is essential for understanding the superconducting mechanism. By using the kz capability of angle-resolved photoemission, we completely determined the SC gap on all five Fermi surfaces (FSs) in three dimensions on Ba0.6K0.4Fe2As2 samples. We found a marked kz dispersion of the SC gap, which can derive only from interlayer pairing. Remarkably, the SC energy gaps can be described by a single 3D gap function with two energy scales characterizing the strengths of intralayer Δ1 and interlayer Δ2 pairing. The anisotropy ratio Δ1/Δ2, determined from the gap function, is close to the c-axis anisotropy ratio of the magnetic exchange coupling Jc/Jab in the parent compound. The ubiquitous gap function for all the 3D FSs reveals that pairing is short-ranged and strongly constrains the possible pairing force in the pnictides. A suitable candidate could arise from short-range antiferromagnetic fluctuations.
Full text
Available for:
IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
We present X-ray timing results of the new black hole candidate MAXI J1535−571 during its 2017 outburst from Hard X-ray Modulation Telescope (Insight-HXMT) observations taken from 2017 September 6 to ...23. Following the definitions given by Belloni, we find that the source exhibits transitions from the low/hard state to the hard intermediate state, and eventually to the soft intermediate state. Quasi-periodic oscillations (QPOs) are found in the intermediate states, which suggest different types of QPOs. With the large effective area of Insight-HXMT at high energies, we are able to present the energy dependence of the QPO amplitude and centroid frequency up to 100 keV, which has rarely been explored by previous satellites. We also find that the phase lag at the type-C QPOs centroid frequency is negative (soft lag) and strongly correlated with the centroid frequency. Assuming a geometrical origin of type-C QPOs, the source is consistent with being a high-inclination system.
The singly Cabibbo-suppressed decay D+s → K + π + π − π 0 is observed by using a data set corresponding to an integrated luminosity of 6.32 fb − 1 recorded by the BESIII detector at the ...centre-of-mass energies between 4.178 and 4.226 GeV. The first amplitude analysis of D+s → K + π + π − π 0 reveals the sub-structures in this decay and determines the fractions and relative phases of different intermediate processes. The dominant intermediate process is D+s → K *0 ρ + , with a fit fraction of (40 . 5 ± 2 . 8 stat . ± 1 . 5 syst . )%. With the detection efficiency based on our amplitude analysis, the absolute branching fraction for D+s → K + π + π − π 0 is measured to be (9 . 75 ± 0 . 54 stat . ± 0 . 17 syst . ) × 10 − 3 .
•The bulk-equivalent hardness values and their increments of tungsten irradiated with 200keV He+ at 800°C were investigated.•Vacancy like defects in tungsten induced by 200keV He+ at 800°C were ...investigated.•The irradiation induced hardening behavior in tungsten could be explained by the dispersed barrier hardening model.•The irradiation induced hardening in tungsten was consistent with the vacancy like defects.
The irradiation induced hardening and vacancy like defects are investigated as a function of irradiation fluences with 200keV He ion implantation at 800°C in this work. Nano-indentation tests show the irradiation induces hardening and the hardness values increase with increasing irradiation fluences. Doppler broadening spectroscopy analyses of slow positron annihilation find that a large amount of vacancy like defects are produced under irradiation. When the He/dpa ratio is less than about 2.2%He/dpa, the vacancy like defects include mainly empty vacancy clusters and loops, and HenVm complexes. When the He/dpa ratio is more than about 2.2%He/dpa, the vacancy like defects become mainly HenVm complexes with increasing irradiation fluences. Meanwhile, these complexes increase in size and He/V ratio while the irradiation fluences increase. Based on the Orowan hardening mechanism, we discuss the relationship between irradiation induced hardening and defects under indentation, especially the contribution of HenVm complexes to the hardening.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
It was recently suggested that the non-neuronal cholinergic system has a regulatory role in pulmonary inflammation. We investigated this system's involvement in the control of cytokine production by ...the A549 human alveolar epithelial cell line. CXCL8 and acetylcholine (ACh) concentrations were measured using ELISA and LC–MS/MS, respectively. The mRNA expression of muscarinic receptor (MR) subtypes was determined using RT-PCR. In A549 cells, TNF-α increased the release of CXCL8 and ACh and the expression of the subtype 3 MR (M3R). Furthermore, TNF-α-induced CXCL8 secretion was (i) inhibited by the MR antagonist tiotropium and the M3R antagonist 4-DAMP and (ii) enhanced by the M1/M3R agonist pilocarpine and the cholinesterase inhibitor physostigmine. Taken as a whole, these results suggest that ACh release by A549 cells enhances TNF-α-induced CXCL8 secretion through activation of the M3R. Western blot analysis revealed that pilocarpine and physostigmine enhanced the TNF-α-induced phosphorylation of ERK1/2 and p38 MAPK and the degradation of IκBα. Inhibition of these pathways with specific inhibitors abrogated the pilocarpine-induced CXCL8 release. Our results suggest that the TNF-α-induced secretion of CXCL8 in A549 cells is regulated by the release of ACh, the latter's binding to the M3R and the downstream activation of NF-κB and the ERK1/2 and p38 MAPK signaling pathways. Our findings suggest that MR antagonists may have anti-inflammatory effects by preventing pro-inflammatory events driven by endogenous, non-neuronal ACh.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We demonstrate a kilowatt level Quasi-continuous-wave (QCW) diode-side-pumped Nd:YAG ceramic laser at 1064
nm. The laser system adopts a master oscillator power amplifier scheme (MOPA). The master ...oscillator contains two diode-pumped laser modules. Under the pump power of 2000
W, an output power of 686
W was obtained. After amplified by an identical ceramic laser module, a maximum output power of 1020
W was obtained under a total incident pump power of 3433
W, corresponding to an optical–optical conversion efficiency of 29.7%. At the maximal output power, the repetition frequency was measured to be 1
kHz and the pulse width was 114
μs. To the best of our knowledge, this is the first time to realize QCW side-pumped Nd:YAG ceramic laser system with output power above 1
kW.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Underground Nuclear Astrophysics Experiment in China (JUNA) takes the advantage of the ultra-low background in Jinping underground lab. High current mA level 400 KV accelerator with an ECR source, ...BGO and neutron detectors were commissioned. JUNA studies directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies. In the first quarter of 2021, JUNA performed the direct measurements of
25
Mg
(
p
,
γ
)
26
Al
,
19
F
(
p
,
α
)
16
O
,
13
C
(
α
,
n
)
16
O
and
12
C(
α
,
γ
)
16
O near the Gamow window. The experimental results reflect the potential of JUNA with higher statistics, precision and sensitivity of the data. The preliminary results of JUNA experiment and future plan are given.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Air bubbles may be injected and attached on the surface of a moving underwater vehicle to enhance its speed. Thus the nonlinear interactions between the moving body at a variable speed and the ...deformable bubble attached are of importance. In this paper, a body with an air bubble attached at a variable speed is simulated using the boundary-element method together with the potential theory. The motion of the body and deformation of the bubble under the action of gravity are considered in a moving coordinate system fixed on the body. Bernoulli equation and auxiliary function method in this moving coordinate system are adopted to calculate the pressure and fluid force on the body. Convergence study with mesh and time step has been undertaken with good convergence obtained. Simulated results have also been compared with other published numerical results and good agreement achieves. On this basis, the influences of different parameters have been further studied, such as Froude number, cavitation number and body acceleration. It is found that bubble shape and jet direction are influenced by the gravity a lot in the range of parameters considered and various jet patterns may generate such as inward jet, oblique jet or upward jet.
•The fully nonlinear interaction between moving body, deformable bubble and gravity is simulated.•A numerical method to study the pressure on the body in a moving coordinate system is proposed.•The bubble jet will change from inward to oblique and then to upward as Froude number decreases.•Acceleration of the body has little influence on bubble evolution but important impact on resultant fluid force.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
PDF
