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In this paper, the fatigue characteristics of the electric drive system in driving load cases and random vibration load cases are analyzed numerically and experimentally. The fatigue life of the driving system under these two load cases is analyzed by using the time domain method and frequency domain method respectively. The results show that the damage of rotating parts (gear and bearing) mainly occurs in driving load cases, and the damage of gear and bearing in the driving load cases is 71.78% and 43.46% respectively. Fixed components (housing and suspension support) have certain damage in driving load cases and random vibration load cases, and the damage is greater in driving load cases. The damage of housing and suspension support in driving load cases is 10.6% and 0.167% respectively; the damage under random vibration load cases is 1.32 × 10−11and 3.12 × 10−11respectively. Based on the above conclusions, it is suggested that the driving load case tests for electric driving system are necessary, but it is not necessary to do random vibration tests only for electric driving system, or the number of random vibration tests can be reduced. This not only ensures the reliability of the components, but also helps to reduce the test cost.

We show that the synthetic spin-orbit coupling created in current ultracold atom experiments provides physicists a unique tool to control the Luttinger liquid parameter K of weakly interacting bosons in one dimension. At a critical value of the Raman coupling strength Ωc, K is suppressed down to zero, and the characteristic quasilong- range order for ordinary one-dimensional quantum systems disappears. Consequently, the single-particle correlation function decays exponentially at the ground state, signifying the rise of a one-dimensional quantum many-body state beyond the standard Luttinger liquid paradigm. Momentum distribution, as well as scaling relations for various quantities in the vicinity of the critical point, can be used as a direct diagnosis of this non-Luttinger quantum liquid. [ABSTRACT FROM AUTHOR]

Motivated by the recent rapid development of the field of quantum gases in optical lattices, we present a comprehensive study of the spectrum of ultracold atoms in a one-dimensional optical lattice subjected to a periodic lattice modulation. Using the time-dependent density matrix renormalization group method, we study the dynamical response due to lattice modulations in different quantum phases of the system with varying density. For the Mott-insulating state, we identify several excitation processes, which provide important information about the density profile of the gases. For the superfluid, the dynamical response can be well described in a local density approximation. This simplification can be valuable in understanding the strong-correlated superfluid in a slow-varying harmonic potential. All these spectroscopic features of an inhomogeneous system can be used as a test for the validity of the Bose-Hubbard model in a parabolic trapping potential. [ABSTRACT FROM AUTHOR]