We present an empirical stellar spectra library created using spectra from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR5. This library represents a uniform data set ...ranging from 3750 through 8500 K in effective temperature (Teff), from −2.5 through +1.0 dex in metallicity (Fe/H), and from 0 to 5.0 dex in gravity (log g). The spectra in the library have resolutions R ∼ 1800, with well-calibrated fluxes and rest-framed wavelengths. Using a large number of red stars observed by LAMOST, we generated denser K-type templates to fill in data missing from current empirical spectral libraries, particularly the late K type. For K giants, we calibrated the spectroscopic surface gravities against the asteroseismic surface gravities. To verify the reliability of the parameters labeled for this library, we performed an internal cross-validation using a χ2 minimization method to interpolate the parameters of each individual spectrum using the remaining spectra in the library. We obtained precisions of 41 K, 0.11 dex, and 0.05 dex for Teff, log g, and Fe/H, respectively, which means the templates are labeled with correct stellar parameters. Through external comparisons, we confirmed that measurements of the stellar parameters through this library can achieve accuracies of approximately 125 K in Teff, 0.1 dex in Fe/H and 0.20 dex in log g without systematic offset. This empirical library is useful for stellar parameter measurements because it has large parameter coverage and full wavelength coverage from 3800 to 8900 .
Highlights • Type-I–III receptors for histamine expresses in nodose of male and female rats. • H2 R and H3 R expressions are higher in females than those in males. • H2 R highly expresses in ...low-threshold and sex-specific subset of Ah-type neurons. • Sex- and afferent-specific expression of histamine receptors in vagal afferents. • This difference in HR expression may contribute greatly to incidence of asthma.
The results of recent research on the dynamic response, failure mechanism, and changes in the load-transfer paths of a half-scale three-story, three-bay, and three-span reinforced concrete frame ...subjected to a series of sudden column removals are presented. Three phases of testing were carried out, including the removal of a corner column and a column adjacent to the corner column along the short span direction, two middle exterior columns along the long span direction, and one interior column. The column removal was enabled by using a gas cannon. The dynamic response at critical locations after the imposed failure of the respective columns was observed. The removal of the corner column followed by the adjacent column resulted in only an essentially elastic response of the structure. The removal of an interior column resulted in only small deflections. The removal of the two first-story exterior columns resulted in significant vertical deflections of the middle exterior columns and significant yielding at adjacent beams that framed into the two middle exterior columns.
From December 2011 to May 2014, about 5 fb^-1 of data were taken with the BESIII detector at center-of- mass energies between 3.810 GeV and 4.600 GeV to study the charmonium-like states and higher ...excited charmonium states. The time-integrated luminosity of the collected data sample is measured to a precision of 1% by analyzing events produced by the large-angle Bhabha scattering process.
Abstract We report the timing analysis of PSR J1846−0513, a pulsar discovered by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in Commensal Radio Astronomy FAST Survey. The pulsar ...possesses a spin period of 23.36 ms and a spin-down rate ( P ̇ ) of 1.0106(3) × 10 −18 s s −1 , and it is located in an eccentric orbit ( e ∼0.208) with an orbital period of 0.61 days. The characteristic age and surface magnetic field of the pulsar are found to be 366.62 Myr and 4.9178 × 10 9 G, respectively, indicating that it is a recycled pulsar. Using over two years of timing data, we measure the periastron advance ω ̇ = 0.8956(8) deg yr −1 . By assuming that this effect is purely relativistic, we have estimated the total mass M = 2.6287(35) M ⊙ and obtained an upper limit for the pulsar mass and a lower limit for the companion’s mass. Our results indicate that this is a double neutron star system.
•Significant melting enthalpy reduction was found in NPCMs.•Interaction between nanoparticles and PCM contributes to the reduction.•A parameter was defined to evaluate the effect of the ...interaction.•Dense phase is the internal reason for NPCM melting enthalpy reduction.
In order to enhance the thermal conductivity of phase change material (PCM), many studies on preparation of composite PCM with nanoparticles (NPCM) have been performed. However, most of the studies only focused on PCM thermal conductivity enhancement, and ignored the melting enthalpy reduction caused by nanoparticles. In present paper, molecular dynamics (MD) method was adopted to study the effect of nanoparticles (CuO) on PCM (paraffin) melting enthalpy and to reveal the mechanism of PCM melting enthalpy reduction. The results showed that the melting enthalpy quickly decreased with the increase of nanoparticle mass fractions. For the NPCM with 19.72 wt.% nanoparticles, the melting enthalpy decreased by about 51.5%. The interactions between nanoparticles and PCM also contribute to melting enthalpy reduction except the nanoparticle mass fraction. Then, a parameter (Fc) was defined to reveal the effect of the interactions on NPCM melting enthalpy. With the nanoparticle mass fraction increasing, the interaction was strengthened and the value of Fc was quickly decreased, especially when the nanoparticle mass fraction was lower than 10 wt.%. The dense phase of paraffin was found around nanoparticles. The existence of dense phase caused by the interaction between nanoparticles and PCM is the internal reason for NPCM melting enthalpy reduction.
Gravitational‐wave high‐energy Electromagnetic Counterpart All‐sky Monitor (GECAM) is a space‐borne instrument dedicated to monitoring high‐energy transients, including Terrestrial Gamma‐ray Flashes ...(TGFs) and Terrestrial Electron Beams (TEBs). We implemented a TGF/TEB search algorithm for GECAM, with which 147 bright TGFs, 2 typical TEBs and 2 special TEB‐like events are identified during an effective observation time of ∼9 months. We show that, with gamma‐ray and charged particle detectors, GECAM can effectively identify and distinguish TGFs and TEBs, and measure their temporal and spectral properties in detail. A very high TGF‐lightning association rate of ∼80% is obtained between GECAM and GLD360 in east Asia region.
Plain Language Summary
Terrestrial gamma‐ray flashes (TGFs) and Terrestrial Electron Beams (TEBs) represent the most energetic radioactive phenomena in the atmosphere of the Earth. They reflect a natural particle accelerator that can boost electrons up to at least several tens of mega electron volts and produce gamma‐ray radiation. With novel detection technologies, Gravitational‐wave high‐energy Electromagnetic Counterpart All‐sky Monitor (GECAM) is a new powerful instrument to observe TGFs and TEBs, as well as study their properties. For example, it is difficult for most space‐borne high‐energy instruments to distinguish between TGFs and TEBs. However, we show here that, with the joint observation of gamma‐ray and charged particle detectors, GECAM can effectively identify TGFs and TEBs. GECAM can also reveal their fine features in the light curves and spectra.
Key Points
During 9‐month observation, Gravitational‐wave high‐energy Electromagnetic Counterpart All‐sky Monitor (GECAM) has detected 147 bright Terrestrial Gamma‐ray Flashes (TGFs), 2 typical Terrestrial Electron Beams (TEBs), and 2 special TEB‐like events
With novel detector design, GECAM can effectively classify TGFs and TEBs, and reveal their fine temporal features
We obtained a very high TGF‐lightning association rate (∼80%) between GECAM and GLD360 in east Asia region
ABSTRACT
Based on Insight-HXMT data, we report on the pulse fraction evolution during the 2017–2018 outburst of the newly discovered first Galactic ultraluminous X-ray (ULX) source Swift ...J0243.6+6124. The pulse fractions of 19 observation pairs selected in the rising and fading phases with similar luminosity are investigated. The results show a general trend of the pulse fraction increasing with luminosity and energy at supercritical luminosity. However, the relative strength of the pulsation between each pair evolves strongly with luminosity. The pulse fraction in the rising phase is larger at luminosity below 7.71 × 1038 erg s−1, but smaller at above. A transition luminosity is found to be energy independent. Such a phenomenon is first confirmed by Insight-HXMT observations and we speculate that it may have relation with the radiation-pressure-dominated accretion disc.
Based on an e+e− collision data sample corresponding to an integrated luminosity of 567 pb−1 taken at the center-of-mass energy of s=4.6 GeV with the BESIII detector, we measure the absolute ...branching fraction of the inclusive decay Λc+→Λ+X to be B(Λc+→Λ+X)=(38.2−2.2+2.8±0.9)% using the double-tag method, where X refers to any possible final state particles. In addition, we search for direct CP violation in the charge asymmetry of this inclusive decay for the first time, and obtain ACP≡B(Λc+→Λ+X)−B(Λ¯c−→Λ¯+X)/B(Λc+→Λ+X)+B(Λ¯c−→Λ¯+X)=(2.1−6.6+7.0±1.6)%, a statistically limited result with no evidence of CP violation.
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The study ofCoNb2O6sits at the confluence of simplicity and complexity: on one hand, the model for Ising chains—the building blocks ofCoNb2O6—in a transverse field can be exactly solved and, thus, ...serves as an archetype of quantum criticality; on the other hand, the weak but nonzero interchain coupling adds geometric frustration to the stage, substantially complicating the phase diagram. Here we utilize low-temperature specific heat and thermal conductivity measurements to study the low-lying magnetic excitations inCoNb2O6and its spin-1 analogNiNb2O6. The thermal conductivity is found to be suppressed around the quantum critical point, where the specific heat is enhanced due to gapless magnetic excitations, pointing to the localized nature of the latter. These results highlight the predominant role of frustration in determining the quantum critical magnetic excitations of spin chains, which may furthermore underlie the remarkable similarities between the phenomenology of these spin-1/2and spin-1 systems.
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