The numbers of psi(3686) events accumulated by the BESIII detector for the data taken during 2009 and 2012 are determined to be (107.0 +/- 0.8)x10(6) and (341.1 +/- 2.1)x10(6), respectively, by ...counting inclusive hadronic events, where the uncertainties are systematic and the statistical uncertainties are negligible. The number of events for the sample taken in 2009 is consistent with that of the previous measurement. The total number of psi(3686) events for the two data taking periods is (448.1 +/- 2.9) x 10(6).
The electronic and transport properties of the half-Heusler compound LaPtSb are investigated by performing first-principles calculations combined with semi-classical Boltzmann theory and deformation ...potential theory. Compared with many typical half-Heusler compounds, LaPtSb exhibits an obviously larger power factor at room temperature, especially for the n-type system. Together with the very low lattice thermal conductivity, the thermoelectric figure of merit (
ZT
) of LaPtSb can be optimized to a record high value of 2.2 by fine tuning the carrier concentration.
The electronic and transport properties of the half-Heusler compound LaPtSb are investigated by performing first-principles calculations combined with semi-classical Boltzmann theory and deformation potential theory.
As typical and significant structural elements, double-beam systems widely exist in practical engineering applications such as some subgrades and highway bridges. This paper focuses on presenting the ...closed-form solutions of the forced transverse vibration of a coupled Timoshenko double-beam system under compressive axial load. The solutions are generalized and can be suitable for any boundary conditions. The present model is generalized and can be reduced to any existing double-beam systems. Timoshenko model is employed to express the two beams of the double-beam system. Using the Laplace transform, the steady-state Green's functions of the coupled double-beam system can be derived. Since the Green's functions are fundamental solutions of the system, the steady-state forced vibration solutions can be obtained with the help of the superposition principle. In the numerical section, the present solutions are compared with the other known results along with FEM solutions for verification. In addition to the influences of the stiffness modulus of Winkler elastic layer and axial force on the present solutions that should be discussed, the influences of some physical parameters, such as the height-to-length ratio, external frequency, shearing effect, rotational inertia, on the closed-form solutions will also be presented. The effect of the compressive axial load is studied in this work.
The forced transverse vibration of a coupled Timoshenko double-beam system under compressive axial load, and the boundary conditions are generalized ones. Display omitted
•Forced vibration solutions for Timoshenko double-beam systems are obtained.•A generalized model that can be reduced to a Double-Euler beam model is proposed.•The solutions are generalized and can be suitable to any boundary conditions.•Green's function method is used to obtain the closed-form solutions.•Dynamic buckling phenomena induced by the axial force are studied.
ABSTRACT
We report on the Insight-HXMT observations of the new black hole X-ray binary MAXI J1820+070 during its 2018 outburst. Detailed spectral analysis via the continuum fitting method shows an ...evolution of the inferred spin during its high soft sate. Moreover, the hardness ratio, the non-thermal luminosity and the reflection fraction also undergo an evolution, exactly coincident to the period when the inferred spin transition takes place. The unphysical evolution of the spin is attributed to the evolution of the inner disc, which is caused by the collapse of a hot corona due to condensation mechanism or may be related to the deceleration of a jet-like corona. The studies of the inner disc radius and the relation between the disc luminosity and the inner disc radius suggest that, only at a particular epoch, did the inner edge of the disc reach the innermost stable circular orbit and the spin measurement is reliable. We then constrain the spin of MAXI J1820 + 070 to be $a_*=0.2^{+0.2}_{-0.3}$. Such a slowly spinning black hole possessing a strong jet suggests that its jet activity is driven mainly by the accretion disc rather than by the black hole spin.
A
bstract
Using 6
.
32 fb
−
1
of
e
+
e
−
collision data collected at the center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we perform an amplitude analysis of the decay
D
...s
+
→ K
+
π
+
π
−
and determine the amplitudes of the various intermediate states. The absolute branching fraction of
D
s
+
→ K
+
π
+
π
−
is measured to be (6
.
11
±
0
.
18
stat
.
±
0
.
11
syst
.
)
×
10
−
3
. The branching fractions of the dominant intermediate processes
D
s
+
→ K
+
ρ
0
, ρ
0
→ π
+
π
−
and
D
s
+
→ K
*
(892)
0
π
+
, K
*
(892)
0
→ K
+
π
−
are determined to be (1
.
96
±
0
.
19
stat
.
±
0
.
23
syst
.
)
×
10
−
3
and (1
.
85
±
0
.
12
stat
.
±
0
.
13
syst
.
)
×
10
−
3
, respectively. The intermediate resonances
f
0
(500),
f
0
(980), and
f
0
(1370) are observed for the first time in this channel.
A recent model developed to predict the smallest grain sizes obtainable by severe plastic deformation has worked well for materials with medium to high stacking fault energies (SFEs) but not for ...those with low SFEs. To probe this issue, experiments were conducted using a Cu–30wt.% Zn alloy with a very low SFE of 7mJ/m2 as the model material. High-pressure torsion was used as the grain refinement technique. The results indicate that stacking faults and twin boundaries play a key role in the grain refinement process such that the smallest achievable grain size is determined by the highest stacking fault and twin density that the system is able to produce. An amorphization of grain boundaries was also observed in the final structure. These observations are very different from those reported for materials having medium to high SFEs and they confirm the operation of a different grain refinement mechanism.
A
bstract
Using a sample of (10
.
09
±
0
.
04)
×
10
9
J/ψ
decays collected with the BESIII detector, partial wave analyses of the decay
J
/
ψ
→
γ
K
S
0
K
S
0
π
0
are performed within the
K
S
0
K
S
0
...π
0
invariant mass region below 1.6 GeV/
c
2
. The covariant tensor amplitude method is used in both mass independent and mass dependent approaches. Both analysis approaches exhibit dominant pseudoscalar and axial vector components, and show good consistency for the other individual components. Furthermore, the mass dependent analysis reveals that the
K
S
0
K
S
0
π
0
invariant mass spectrum for the pseudoscalar component can be well described with two isoscalar resonant states using relativistic Breit-Wigner model, i.e., the
η
(1405) with a mass of
1391.7
±
0.7
−
0.3
+
11.3
MeV/
c
2
and a width of
60.8
±
1.2
−
12.0
+
5.5
MeV, and the
η
(1475) with a mass of
1507.6
±
1.6
−
32.2
+
15.5
MeV/
c
2
and a width of
115.8
±
2.4
−
10.9
+
14.8
MeV. The first and second uncertainties are statistical and systematic, respectively. Alternate models for the pseudoscalar component are also tested, but the description of the
K
S
0
K
S
0
π
0
invariant mass spectrum deteriorates significantly.
A
bstract
With data samples collected with the BESIII detector at seven energy points at
s
= 3
.
68
−
3
.
71 GeV, corresponding to an integrated luminosity of 333 pb
−
1
, we present a study of the Λ ...transverse polarization in the
e
+
e
−
→
Λ
Λ
¯
reaction. The significance of polarization by combining the seven energy points is found to be 2.6
σ
including the systematic uncertainty, which implies a non-zero phase between the transition amplitudes of the
Λ
Λ
¯
helicity states. The modulus ratio and the relative phase of EM-
psionic
form factors combined with all energy points are measured to be
R
Ψ
=
0.71
−
0.10
+
0.10
±
0.03 and ∆Φ
Ψ
=
23
−
8.0
+
8.8
±
1.6
°
, where the first uncertainties are statistical and the second systematic.
PDF
