Showing papers by "Yu-xi Liu published in 2022"
2 citations
TL;DR: In this article , the ringing phenomenon was observed in a magnomechanical system for the first time, which is induced by the interference between the microwave photons converted from the damped phonons and the probing microwave photons.
Abstract: The ringing phenomenon has been studied in optical whispering gallery mode (WGM) resonators and can be used to sense the ultrafast process in spectroscopy. Here we observe the ringing phenomenon in a magnomechanical system for the first time, which is induced by the interference between the microwave photons converted from the damped phonons and the probing microwave photons. This interference eventually appears as a transparency window even along with the ringing phenomenon in the measured microwave reflection spectrum, which is influenced by the scanning speed and the input power. Then, the ringing spectroscopy is used to measure the coupling strength between the magnon and phonon modes, and outline the displacement profile of S 1 , 2 , 2 mechanical mode in a YIG microsphere, demonstrating the theoretical analysis. In addition, the ring-up spectroscopy is developed in our magnomechanical system, laying the foundation for fast sensing based on mechanical motion.
1 citations
1 citations
TL;DR: In this paper , a two-dimensional axial-symmetric particle-in-cell code with Monte Carlo collisions is used in the numerical simulation of tip-to-plate electrode configuration.
Abstract: The breakdown of a vacuum arc under high applied voltage conditions usually occurs on very short time and space scales, and a deep understanding of these processes is essential to extend the application of vacuum arc devices. To study the time and spatial evolution of plasma parameters during vacuum breakdown, a two-dimensional axial-symmetric particle-in-cell code with Monte Carlo collisions is used in the numerical simulation of tip-to-plate electrode configuration. In this simulation, in addition to considering the primary and secondary ionization of copper atoms, the excitation and de-excitation processes of copper atoms are also introduced so that the evolution of the light intensity of the vacuum arc in the different stages of breakdown processes can be obtained by tracking the de-excitation process of the atoms, which can be considered a virtual camera. In this way, the cathode radiance, anode light expansion, arc channel establishment, and arc quenching processes can be visually observed, and the trends are consistent with the images taken by Intensified Charge-Coupled Device (ICCD) and streak cameras reported in the literature. The analysis of the sputtering amount of the anode material due to the impact of the cathode plasma to the anode surface shows that the contribution of atoms, singly, and doubly ionized ions to the sputtering of the anode material varies at different stages of the discharge.
1 citations
TL;DR: Wang et al. as mentioned in this paper explored systemic glucocorticoid prescription pattern and factors of inappropriate use in primary care institutions in Guizhou province of Southwest China in 2020.
Abstract: Inappropriate use of glucocorticoids in primary care institutions is serious. It not only causes economic burden, but leads to many adverse reactions. The purpose of this study is to explore systemic glucocorticoid prescription pattern and factors of inappropriate use in primary care institutions.This is a retrospective study. Systemic glucocorticoids prescribed in 58 primary care institutions in Guizhou province of Southwest China in 2020 were selected from the Health Information System. All prescriptions were classified as appropriate or inappropriate use. Inappropriate use was classified into the following two categories: (a) Inappropriate indications; (b) Inappropriate selection of glucocorticoids. Multivariate analysis was used to explore the factors associated with inappropriate use of systemic glucocorticoids.A total of 63,315 glucocorticoid prescriptions were included in the analysis. Diseases of the respiratory system (60.8%) and diseases of the skin and subcutaneous tissue (23.1%) were the most common indications for use. Injections (89.8%) predominated and dexamethasone (86.5%) was the most prescribed glucocorticoid. 68.2% of all prescriptions were inappropriate. Compared to physicians with a college degree, physicians with a junior college (OR: 1.12, 95% CI: 1.08-1.17) and technical secondary education (OR: 1.12, 95% CI:1.05-1.19) were more likely to prescribe glucocorticoids inappropriately as were attending physicians (OR: 1.12, 95% CI: 1.01-1.25) and resident physicians (OR: 1.31, 95% CI: 1.15-1.48) compared to associate chief physicians. The risk of inappropriate glucocorticoid use was highest in patients 65 years of age and older (OR: 6.00, 95% CI: 5.62-6.40). In contrast, prescriptions given by injection were more likely to be used inappropriately than those given orally (OR: 0.44, 95% CI: 0.41-0.46).Inappropriate use of systemic glucocorticoids without appropriate indications was extremely prominent in primary care institutions of Guizhou Province, especially in diseases of the respiratory system and among the elderly. The risk of inappropriate glucocorticoid use was highest in patients 65 years of age and older. It is important to note that physicians younger than 33, with more than 40 years of service, and attending or residents were more likely to inappropriately prescribe glucocorticoids.
27 May 2022
TL;DR: In this paper , the authors proposed that finding the best angle of the workpiece can significantly improve the efficiency of the algorithm and make the marking path more efficient, and compared and discussed the time-consuming situation of their respective algorithms.
Abstract: The laser marking technology integrates Laser Technology, Computer Technology and Mechatronics Technology. In this paper, we design the sawtooth parallel trajectory generation algorithm, the contour parallel trajectory generation algorithm and the pixel model algorithm for the laser marking trajectory model. For three different marking modes, this paper compares and discusses the time-consuming situation of their respective algorithms. Based on the sawtooth parallel traj ectory generation algorithm, this paper proposes that finding the best angle of the workpiece can significantly improve the efficiency of the algorithm and make the marking path more efficient.
TL;DR: In this article , the authors show that common environments shared by nearest neighboring sites in the SSH chain can result in dissipative couplings between sites, and thus change the topologically trivial phase to a nontrivial one.
Abstract: The edge states in a one-dimensional Su-Schrieffer-Heeger (SSH) chain have been extensively studied for their topologically protected properties when there are onsite dissipations induced by independent environments. We here show that common environments shared by nearest neighboring sites in the SSH chain can result in dissipative couplings between sites, and thus change the topologically trivial phase to a nontrivial one. In contrast to usual hybridization of two edge states in the SSH chain with finite size, we find that the dissipative couplings result in oscillations of these hybridized edge states, which are similar to those of Majorana modes in the semiconductor-superconductor nanowire. The parameter for controlling the topological phase of the SSH chain plays the role of the magnetic field in a nanowire for controlling Majorana oscillation. A measurement method for oscillations is proposed. Our study provides a useful way to manipulate and ascertain edge states, and is experimentally feasible within current technology of superconducting quantum circuits.
24 Feb 2022
TL;DR: In this article , the authors demonstrate the resonance fluorescence of a two-level artificial atom strongly coupled to a single-mode cavity field and find that the central peak is determined by the atom spontaneous emission to the open space and the widths of side peaks are largely determined by coherent interaction between the atom and the cavity.
Abstract: We experimentally demonstrate the resonance fluorescence of a two-level artificial atom strongly coupled to a single-mode cavity field. The effect was theoretically predicted thirty years ago by Savage [Phys. Rev. Lett. 63, 1376 (1989)]. The system consists of a superconducting qubit circuit and a one-dimensional transmission line resonator. In addition, a one-dimensional transmission line strongly coupled to the atom serves as an open space. The effect takes place, when a microwave field is applied to the cavity, which in turn is resonantly coupled to the atom. The fluorescence spectrum is measured via the emission into the transmission line. We find that the central peak is determined by the atom spontaneous emission to the open space and the widths of side peaks are largely determined by the coherent interaction between the atom and the cavity, that is, the fluorescence spectrum here is very different from that of the Mollow triplet. We also derive analytical form for the spectrum. Our experimental results agree well with theoretical calculations.