27,538 research outputs found
Semileptonic Meson Decays Into A Highly Excited Charmed Meson Doublet
We study the heavy quark effective theory prediction for semileptonic
decays into an orbital excited -wave charmed doublet, the (, )
states (, ), at the leading order of heavy quark expansion.
The corresponding universal form factor is estimated by using the QCD sum rule
method. The decay rates we predict are and . The branching ratios are
and
, respectively.Comment: 6 pages,2 figure
Solving the Dirac equation with nonlocal potential by Imaginary Time Step method
The Imaginary Time Step (ITS) method is applied to solve the Dirac equation
with the nonlocal potential in coordinate space by the ITS evolution for the
corresponding Schr\"odinger-like equation for the upper component. It is
demonstrated that the ITS evolution can be equivalently performed for the
Schr\"odinger-like equation with or without localization. The latter algorithm
is recommended in the application for the reason of simplicity and efficiency.
The feasibility and reliability of this algorithm are also illustrated by
taking the nucleus O as an example, where the same results as the
shooting method for the Dirac equation with localized effective potentials are
obtained
A quantitative evaluation of metallic conduction in conjugated polymers
As the periodicity in crystalline materials creates the optimal condition for
electronic delocalization, one might expect that in partially crystalline
conjugated polymers delocalization is impeded by intergrain transport. However,
for the best conducting polymers this presumption fails. Delocalization is
obstructed by interchain rather than intergrain charge transfer and we propose
a model of weakly coupled disordered chains to describe the physics near the
metal-insulator transition. Our quantitative calculations match the outcome of
recent broad-band optical experiments and provide a consistent explanation of
metallic conduction in polymers.Comment: 4 pages incl. 3 figure
Effect of ludwigite (B2O3) on high Al2O3 slag and its mechanism used as a new blast furnace welding flux
Based on the measurement of viscosities and critical temperatures of CaO-MgO-SiO2- Al2O3-B2O3 slag system with various B2O3 contents, the slag with higher than 15 mas. % Al2O3 content has the lowest critical temperature and the widest solid-liquid coexisting region at about 2,0 mas. % B2O3. Furthermore, the X-ray diffractometer (XRD) result verified that bechilites whose melting point are low forms. Raman spectra revealed that the effect of network forming on viscosity is smaller than the effect of bechilites, which leads to the slag viscosity decrease with B2O3 addition. Base on the above research, so ludwigite can meet the requirements of a BF welding flux to decrease the critical temperature and improve the fluidity of the high Al2O3 slag
Integration of gradient least mean squares in bidirectional long short-term (LSTM) memory networks for metallurgical bearing ball fault diagnosis
This paper introduces a novel diagnostic approach for bearing ball failures: a synergistic implementation of a bidirectional Long Short-Term Memory (LSTM) network, empowered by Gradient Minimum Mean Square. This method leverages deep analysis of operational data from bearings, enabling the precise identification of incipient bearing ball failures at early stages, thus markedly improving prediction accuracy. Our empirical results underscore the superior performance of this composite methodology in accurately detecting a spectrum of five mechanical bearing ball failure types, achieving a substantial enhancement in diagnostic precision
- …