Laplacian spectral characterization of roses

A rose graph is a graph consisting of cycles that all meet in one vertex. We show that except for two specific examples, these rose graphs are determined by the Laplacian spectrum, thus proving a conjecture posed by Lui and Huang [F.J. Liu and Q.X. Huang, Laplacian spectral characterization of 3-rose graphs, Linear Algebra Appl. 439 (2013), 2914--2920]. We also show that if two rose graphs have a so-called universal Laplacian matrix with the same spectrum, then they must be isomorphic. In memory of Horst Sachs (1927-2016), we show the specific case of the latter result for the adjacency matrix by using Sachs' theorem and a new result on the number of matchings in the disjoint union of paths

Torque Ripple Suppression of Brushless DC Motor Drive System Based on Improved Harmonic Injection Active Disturbance Rejection Control

The positioning accuracy and speed stability of the brushless DC motor (BLDC motor), as the drive element of the optomechanically scanned system (OMSS), are closely interrelated to the final imaging quality of the system. Active disturbance rejection control (ADRC) with strong anti-interference ability, fast response and good robustness is one of the extensively used control strategies. However, the performance of ADRC working in a complicated environment will be limited due to the controller structure, parameter tuning and the influence of multi-source nonlinear disturbance. Therefore, an improved ADRC method is proposed, which can switch between ‘point-to-point control mode’ and ‘stable speed control mode’ according to the system requirements. To further suppress the torque ripple and improve the control performance of the system, an improved harmonic injection scheme is added, and the parameters of improved ADRC are tuned by a slime mould algorithm based on a Levy flight operator (LF-SMA). The stability of the proposed ADRC is proved by Lyapunov stability theory. The experimental results show that the proposed control scheme could be available to reduce the torque ripple of the system

Study on the fault slip rule and the rockburst mechanism induced by mining the panel through fault

Abstract When mining near the fault can cause the fault to slip and release energy, resulting in rockburst and posing a significant safety risk to coal mine production. This paper proposes a numerical simulation method, based on FLAC3D numerical simulation, for calculating the dynamic response of fault slip below the impact of mining. The release patterns of energy from fault slip are compared between mining via the fault from the hanging wall and mining via the fault from the footwall. The dynamic response characteristics of coal and rock mass under the disturbance of fault slip induced dynamic loading are revealed. This research suggests that the fault slip seismic moment (M 0) of the panel mined via the fault from footwall is substantially higher than from hanging wall. Moreover, the disturbance of the footwall panel mining via the fault leads to a more severe disturbance of the surrounding rock mass, resulting in a higher risk of rockburst. Plastic failure of the rock surrounded in the mining area under the strong dynamic loading of fault slip leads to a significant reduction in peak abutment stress, releasing tremendous energy. When the disturbance caused by fault slip dynamic load is relatively small, the maximum abutment stress increases, and the dynamic load increases the energy storage of surrounding rock. Based on energy theory, an energy criterion for the occurrence of fault slip type rockburst has been proposed. The results suggest that strong fault slip dynamic load has an obvious inducing effect on rockburst, and the stronger the dynamic load and greater static load of the rock, the more the manifestation of rockburst

Hupo powder promotes autophagy of menstrual blood-derived stem cells from patients with endometriosis

Objective: To explore the effect of Hupo powder (HP) on autophagy in menstrual blood-derived stem cells (MenSCs) with endometriosis (EMT). Methods: EMT MenSCs (E-MenSCs) and healthy MenSCs (H-MenSCs) were isolated from the menstrual blood of patients with EMT and healthy female participants, respectively. We identified their stem cells’ characteristics via adipogenic and osteogenic differentiation. Twelve male Sprague–Dawley rats received 0.9% NaCl and HP-dispensing granules by gastric irrigation to prepare blank serum and medicated serum, respectively. We used serum concentrations of 5%, 10%, and 20%, each at administered times of 12, 24, and 48 h to select the best condition. These cells were divided into three groups: blank serum of the control group, blank serum of the model group, and medicated serum of the HP group. H-MenSCs were used in the control group, while E-MenSCs were used in the model and HP groups. We analyzed cell viability using a cell counting kit-8 assay, observed cell morphology, evaluated the amounts of autophagosomes and autolysosomes by transmission electron microscopy, and detected the protein expression of autophagy markers (LC3-II and Beclin1) by Western blot. Results: E-MenSCs and H-MenSCs became long fusiform with a diffuse radial pattern, forming lipid droplets and calcium nodules after adipogenic and osteogenic differentiation. We then used the best condition—20% serum and 48 h—for the subsequent experiments. In contrast to the model group, the HP group exhibited lower cell viability (P = .007), larger amounts of autophagosomes and autolysosomes (P < .001 and P = .001, respectively), and higher expression of LC3-II and Beclin1 (P = .021 and P = .019, respectively). Conclusion: Hupo powder can promote autophagy in E-MenSCs, which might be one of the mechanisms underlying its therapeutic effects