External uniform electric field removing flexoelectric effect in epitaxial ferroelectric thin films

Using the modified Landau-Ginsburg-Devonshire thermodynamic theory, it is found that the coupling between stress gradient and polarization, or flexoelectricity, has significant effect on ferroelectric properties of epitaxial thin films, such as polarization, free energy profile and hysteresis loop. However, this effect can be completely eliminated by applying an optimized external, uniform electric field. The role of such uniform electric field is shown to be the same as that of an ideal gradient electric field which can suppress the flexoelectricty effect completely based on the present theory. Since the uniform electric field is more convenient to apply and control than gradient electric field, it can be potentially used to remove the flexoelectric effect induced by stress gradient in epitaxial thin films and enhance the ferroelectric properties.Comment: 5 pages, 3 figure

Effect of salidroside on ventricular remodeling after acute myocardial infarction

Purpose: To investigate the remodeling influence of salidroside (SAL) on the ventricles following acute myocardial infarction (AMI) in rats, and the processes involved.Methods: A total of 65 Sprague Dawley (SD) rats were assigned to 5 groups: sham (n = 13), model, and low-, medium- and high-dose SAL groups given SAL at doses of 12, 34, and 36 mg/day, respectively, with 13 rats in each group. Changes in pathological structure, collagen area, ratio of collagen I/collagen III, left ventricular mass index (LVW/BW), ratio of cardiac weight to body weight (HW/BW), creatine kinase MB isoenzyme (CK-MB), lactate dehydrogenase-1 (LDH-1), endothelin (ET), laminin (LN), and hyaluronic acid (HA) were evaluated. Expression levels of dishevelled-1 (DVL-1) and β-catenin in myocardial tissues of the rats were also determined.Results: The LVW/BW values were significantly higher in the low SAL and medium SAL groups than those in AMI rats, while the ratio of collagen I/III and expression levels of DVL-1 and β-catenin proteins were significantly lower than those in the model group (p < 0.05). The myocardial structure of rats in the sham group was normal, with no obvious lesions. The levels of CK-MB, LDH-1, ET, LN, and HA in medium and high-dose SAL groups were significantly lower than those in the model group (p < 0.05).Conclusion: Salidroside mitigates remodeling of ventricles following AMI in rats by modulating the Wnt/β-catenin signal route

Deformation Analysis and Fixture Design of Thin-walled Cylinder in Drilling Process Based on TRIZ Theory

Thin-walled cylindrical workpiece is easy to deform during machining and clamping processes due to the insufficient rigidi. Moreover, it’s also difficult to ensure the perpendicularity of flange holes during drilling process. In this paper, the element birth and death technique is used to obtain the axial deformation of the hole through finite element simulation. The measured value of the perpendicularity of the hole was compared with the simulated value to verify then the rationality of the simulation model. To reduce the perpendicularity error of the hole in the drilling process, the theory of inventive principle solution (TRIZ) was used to analyze the drilling process of thin-walled cylinder, and the corresponding fixture was developed to adjust the supporting surface height adaptively. Three different fixture supporting layout schemes were used for numerical simulation of drilling process, and the maximum, average and standard deviation of the axial deformation of the flange holes and their maximum hole perpendicularity errors were comparatively analyzed, and the optimal arrangement was optimized. The results show that the proposed deformation control strategy can effectively improve the drilling deformation of thin-walled cylindrical workpiece, thereby significantly improving the machining quality of the parts

Hetero2^2Net: Heterophily-aware Representation Learning on Heterogenerous Graphs

Real-world graphs are typically complex, exhibiting heterogeneity in the global structure, as well as strong heterophily within local neighborhoods. While a growing body of literature has revealed the limitations of common graph neural networks (GNNs) in handling homogeneous graphs with heterophily, little work has been conducted on investigating the heterophily properties in the context of heterogeneous graphs. To bridge this research gap, we identify the heterophily in heterogeneous graphs using metapaths and propose two practical metrics to quantitatively describe the levels of heterophily. Through in-depth investigations on several real-world heterogeneous graphs exhibiting varying levels of heterophily, we have observed that heterogeneous graph neural networks (HGNNs), which inherit many mechanisms from GNNs designed for homogeneous graphs, fail to generalize to heterogeneous graphs with heterophily or low level of homophily. To address the challenge, we present Hetero$^2$Net, a heterophily-aware HGNN that incorporates both masked metapath prediction and masked label prediction tasks to effectively and flexibly handle both homophilic and heterophilic heterogeneous graphs. We evaluate the performance of Hetero$^2$Net on five real-world heterogeneous graph benchmarks with varying levels of heterophily. The results demonstrate that Hetero$^2$Net outperforms strong baselines in the semi-supervised node classification task, providing valuable insights into effectively handling more complex heterogeneous graphs.Comment: Preprin